Future Biorefinery Cellulose Programme Report 2011-2014 by Fibic

Ohjelmatunnukset

Future Biorefineries Products from Dissolved Cellulose Programme Report 2011-2014

FUBIO CELLULOSE PROGRAMME REPORT

13 Ohjelmatunnukset

Future Biorefinery Cellulose Programme Report 2011-2014

CONTENT

Foreword...........................................................................................................................................................5 Promising results in creating new cellulose-based products in novel value chains............6 Introduction.................................................................................................................................................... 8 Ionic liquid based dissolution and regeneration processes........................................................ 12 Water based dissolution and regeneration processes.................................................................40 Textile value chain related to FuBio textile fibres..........................................................................60 New cellulose products............................................................................................................................ 72 Cationic cellulose based chemicals................................................................................................... 102

Copyright Finnish Bioeconomy Cluster FIBIC 2013. All rights reserved. This publication includes materials protected under copyright law, the copyright for which is held by FIBIC or a third party. The materials appearing in publications may not be used for commercial purposes. The contents of publications are the opinion of the writers and do not represent the official position of FIBIC. FIBIC bears no responsibility for any possible damages arising from their use. The original source must be mentioned when quoting from the materials. ISBN 978-952-67969-4-9 (paperback) ISBN 978-952-67969-5-6 (PDF) Layout: Brand United Ltd Printing: Kirjapaino Lรถnnberg Scarf photo (cover) by: Mikko Raskinen

FOREWORD The Finnish forest industry is undergoing active renewal. This is being pursued partly due to changes in the traditional business environment, but also as a response to the opportunities presented by the emerging global bioeconomy. New wood-based products and related new and previously less known value chains are under scrutiny. Alongside paper, board and tissue, which remain the backbone of the pulp industry, the value and versatility of wood as a raw material is being intensively explored to its fullest potential, with a key focus on wood as a viable renewable alternative to petroleum-based resources. The five-year research programme Future Biorefinery (FuBio) was launched in 2009 by the Finnish Bioeconomy Cluster FIBIC (formerly Forestcluster Ltd.). During the first phase of FuBio, several new pathways for wood-based bio-products were studied and pre-evaluated. This laid the ground for the next phase of the programme, which was dedicated to exploiting the most promising results of phase one in order to create new value chains and future business opportunities for the participating companies. In this second phase, launched 2011, FuBio was split into two separate programmes, FuBio Joint Research 2, focusing on bioeconomy research, and the present programme FuBio Products from Dissolved Cellulose. During the programme planning stage, commercial interest towards manmade cellulosic fibres grew to new heights with the price of dissolving pulp peaking in early 2011. This market pull had a clear impact on the planning process. In addition, the first phase of FuBio had introduced some interesting processing alternatives for dissolving and regenerating cellulosic fibres and other shaped particles. These new technologies formed the basis of the new programme. FuBio Products from Dissolved Cellulose focused on developing new processes for dissolving and regenerating cellulose. The aim was twofold: to produce new fibres for use in textiles and nonwoven products, and to produce new cellulose-based materials – such as thermoformable cellulose and cationic cellulose derivatives – for use in water treatment. Understanding the business environment and cost structures as well as value chain formation and value generation were identified as critical, and these aspects were thus built in as a separate, generic work package. Considerable effort was focused on techno-economical modelling and business area and value chain analysis. It was of primary importance for the programme to include as programme partners companies active downstream in the studied value chains – i.e. potential new customers for pulp manufacturing companies. Another objective of the programme was to introduce demonstration products or materials in order to generate interest among potential future customers. This was largely successful, and also public interest was raised through the demo products. FuBio Products from Dissolved Cellulose achieved the majority of its set targets and succeeded in bringing Finland’s forest industry an important step closer to its ultimate goal of renewal. The success stories highlighted in this report are a true embodiment of this achievement.

Kari Kovasin Metsä Fibre, Industrial Coordinator of Programme

PROMISING RESULTS IN CREATING NEW CELLULOSE-BASED PRODUCTS IN NOVEL VALUE CHAINS New value chains will have a major impact on the renewal of the Finnish forest industry.

Jari Räsänen, Stora Enso:

Research performed in FIBIC programmes has

“Fibre processing by using ionic liquids is very

already shown the power of novel value chains

high on our research agenda for the future.”

in creating new processes and products based on new raw materials. The FuBio Cellulose programme (FuBio

A breakthrough in ionic liquids

Products from Dissolved Cellulose) has been the first programme in the FIBIC framework to

A clear breakthrough in the FuBio Cellulose

be focused on a value chain. This approach to

programme was made in research into ionic

a platform for promoting value creation in the

liquids used in the production of textile

Finnish forest industry of the future has proved

fibres. This work has achieved its targets and

to be a good choice. At the same time the

generated very valuable results.

programme has been able to improve general

Ionic liquids have been a key area in the

awareness of new wood-based biorefinery

programme. A team of researchers from the

opportunities among the industrial companies

University of Helsinki and Aalto University has

of the sector.

been developing new ionic liquids systems that

The specific target of the programme was

have high potential in industrial applications.

to develop novel sustainable processes for

They have even been able to spin regenerated

production of staple fibres, new cellulose-based

fibres produced from ionic liquids. This work

materials and water treatment chemicals.

was highlighted when a dress knitted from birch

The industrial partners of the programme believe that the targets have been met very well, although the original ambition level was high, as it has to be in this kind of research.

cellulose fibre was displayed at a Marimekko fashion show in the spring of 2014. The combined efforts of the University of Helsinki and Aalto University have contributed

The partners represented a broad selection of

to the formation of ionic liquids competence on

forest cluster companies. In the following chapters

which the future application-oriented research

the companies highlight the business relevance

can be built.

of the results achieved in the programme. Margareta Hulden, Suominen Nonwovens: “The results in the ionic liquids research indicate many new product opportunities for wood-based

Kari Kovasin, Metsä Fibre:

pulp as a feedstock. As our company makes

“The industrial concepts of ionic liquids will

nonwovens, we would be a downstream user of the

require further development, but the roadmap

potential new products, but we feel that it is always

has been clearly defined by the results achieved

beneficial to be involved at an early stage in the

in the FuBio Cellulose programme.”

development of raw materials that we can utilize.”

FUBIO CELLULOSE PROGRAMME REPORT

Feasibility studies proved to be of great importance

A good basis for further development The programme and its results have been very

Several industrial participants have expressed

innovative and future-oriented. And it has given a

appreciation for the techno-economic feasibility

proof of concept for the high-value precommercial

analyses of selected value chains and novel

research in forest-based sector in Finland.

cellulose-based processes performed in the FuBio Cellulose programme.

The joint research teams and knowhow platform created by the programme will make

Without understanding the characteristics of

it easy to continue the work. Many companies

new value chains that may provide companies

already have plans for how they will use some

in the pulp and paper industry with new

of the results in the company-specified future

businesses, it is extremely difficult to develop

development projects.

the concepts required and to steer the research in the correct direction. Moreover,

The participants agree that the results point in the right direction, but more work is needed

considering

the

techno-

before business potential can be determined.

economic aspect at an early stage of the

A good example of common interest for the

project, the management group and project

combined research efforts and cooperation is

teams were aided in the prioritisation and

the new Advanced Cellulose for Novel Products

selection of development paths.

(ACel) programme that FIBIC launched in the summer of 2014.

Esa Hassinen, UPM-Kymmene: “Upgrading wood-based cellulose to higher-value products fits well with our strategic targets. Broadening the use of wood and fibres, and using biomaterials for new and existing applications, are good candidates for future businesses.”

Kari Saari, Kemira: “The knowledge created in activation and modification of cellulose can be utilized broadly in future programmes. Kemira will continue to study production and utilization of cellulosebased products in different applications. We expect good ongoing collaboration with the competent partners we have had in the FuBio

Advances in several areas

Cellulose programme.”

Great advances were made in several research areas of the FuBio Cellulose programme. For example, it developed and demonstrated a new cellulose dissolving-regeneration process with high sustainability and quality features, which is seen as a promising new alternative. Non-fibre

products,

such

absorbent

materials, have also been regenerated. They will be suitable for a great variety of end-products in the future. Another major focus was to develop watersoluble cellulosic products to be used in various water

treatment

paper

manufacturing

processes. They are good bio-based candidates for the future processes.

FUBIO CELLULOSE PROGRAMME REPORT

INTRODUCTION Background Future Biorefinery (FuBio) has been a strategic

strategic targets of generating new end uses for

focus area of the Finnish Bioeconomy Cluster

wood and fibre and using biomaterials in new and

(FIBIC) during 2009-2014. The overall objective

existing applications. In Finland, industrial interest

of FuBio research and development was to

and activity towards novel, wood cellulose-based

establish

globally-competitive

regenerated fibre products are on the rise. This is

knowledge platforms for the renewal of

due mainly to promising market trends, especially

existing forest industry and the creation of new

in textile fibres, combined with environmental

business. The focus has been on creating new

considerations related to the current dominant

value chains in which biomass-based materials

raw material, cotton. In addition to fibre, other

and chemicals are applied in substantial global

products such as films, beads and other cellulosic

markets. The potential markets of focus are

particles can also be regenerated, opening

both well-known to the forest industry (e.g.

opportunities for a wide range of end products.

fibre-based packaging) as well as essentially

Furthermore,

new (e.g. textiles, nonwovens, polymers,

manipulation of the cellulose chain paves the way

resins

Finland

targeted

functionalization

composites).

towards generation of water soluble cellulosic

The creation of new biorefinery value chains

products for use in water treatment and paper

requires deep understanding of the biomass

manufacture, as well as an exciting new target

structure.

area â&#x20AC;&#x201C; thermoplastic cellulose.

and

thermoformable

addition,

new

processing

technologies must be developed hand in

FuBio Cellulose focused on the development

hand with new biorefinery concepts and their

and evaluation of novel sustainable processing

related value chains. Understanding of the

concepts for selected cellulose products. The

markets and freedom-to-operate are also

programme aimed to promote the development

needed, and the first steps towards future

industrial partnerships must be taken.

of sustainable wood cellulose dissolution,

the

basic

knowledge

and

techniques

Biorefinery

regeneration and functionalisation developed

programme (FuBio Joint Research 1) was

in FuBio 1 towards process concepts suitable

completed in May 2011. This research was

for industrial feasibility evaluation through

thereafter continued through two separate

cellulose-focused and process- and product-

programmes, FuBio Joint Research 2 (FuBio

oriented high-quality research.

The

first,

two-year

Future

JR2) and FuBio Products from Dissolved

The three-year FuBio Cellulose research

Cellulose (FuBio Cellulose). FuBio Cellulose,

programme had total budget of 11.6 million euros.

the focus of this report, was a value chain

The Finnish Funding Agency for Innovation

oriented programme building on the knowledge

(Tekes) provided 60% of the financing, with

generated in FuBio Joint Research 1 on novel

the remainder sourced from the participating

cellulose solvents and the modification of

companies and research institutes.

dissolved

cellulose

produce

bio-based

materials and chemicals. The motivation for the FuBio Cellulose value chain programme stemmed from the needs of the radically evolving forest industry. Upgrading of wood cellulose to higher value products fits the

FUBIO CELLULOSE PROGRAMME REPORT

Programme goals and structure The main goal of FuBio Cellulose was to develop

factors affecting the dissolution and regeneration

novel sustainable processes for the production

of pulp cellulose to state-of-the-art water-based

of i) regenerated cellulose staple fibres, ii) novel

Biocelsol system, which was used as a reference.

functional materials based on cellulose beads,

In both approaches, special emphasis was given

nonwovens

structural

to demonstration of the properties of novel

materials, and iii) cationic cellulose chemicals for

regenerated fibres in clothing applications and

water treatment. The programme was composed

modelling the technical and economic feasibility

of five interlinked work packages contributing

of the most promising novel processes.

thermoformable

to these selected focus areas (see Figure 1). The

The second target of the programme was

programmeâ&#x20AC;&#x2122;s value-chain approach aimed at

to develop processes for the production of

building technologies and expertise in dissolution,

two new high-volume products or product

regeneration and product development within

platforms based on cellulose beads, nonwovens

the selected areas, thus providing a platform

and thermoformable structures from dissolved

for future value creation for the Finnish forest

cellulose,

industry and cellulose converting industry value

regeneration. The end-product areas of focus

chains. Concrete process concepts were built

were hygienic products, packaging, and medical

based on the selected research paths. Techno-

component carriers, all selected based on market

economic evaluations were carried out for

studies carried out in the programme. The

selected concepts and these guided the technical

research focused on processes for producing

process development work throughout the

absorbing cellulose materials, thermoformable

programme. Market analyses provided valuable

cellulose derivatives and slow-release cellulose

information on the value chains in general and on

beads. Special attention was paid to economic

the value generation mechanisms of the selected

factors and the properties of the cellulose

value chains.

materials produced. Demonstrations of the

The first target of the programme was to develop a new process for the production of

without

the

use

spinning

most promising materials were targeted in all of the focus end-product areas.

cellulosic staple fibres from dissolving grade

The third target of the programme was to

pulp. The main emphasis was on sustainable,

develop a new process for producing a water-

techno-economically feasible process concepts

soluble,

that could replace the current industrial NMMO-

chemical product. The research focused on the

based lyocell process or viscose process. The

development of a techno-economically feasible

research focused on two approaches: ionic liquid

synthesis

based dissolution and fibre regeneration, and

cellulose derivatives from wood pulp. Two main

water-based dissolution and fibre regeneration.

synthesis lines â&#x20AC;&#x201C; water-based and organic solvent

The ionic liquid based process development drew

based â&#x20AC;&#x201C; were targeted after the initial screening

on the knowledge on cellulose-dissolving ionic

phase. The most promising synthesis products

liquids developed (at University of Helsinki) and

produced at laboratory scale were tested as

the new dry-wet spinning equipment line built (at

paper and/or water processing chemicals and

Aalto University) by FIBIC during FuBio JR1. The

benchmarked in selected applications against

research on water-based process development

commercial reference chemicals.

cellulose-based

route

for

cationic

polyelectrolyte

water-soluble

focused on generating basic understanding of the

FUBIO CELLULOSE PROGRAMME REPORT

Management of the programme The FuBio Cellulose programme was administered

the FuBio Cellulose programme and the whole

by a Management Group (MG) comprising

Future Biorefinery entity in Finland.

representatives from industry and academia. Execution of the programme was headed by a Programme Manager together with Industrial and Scientific Coordinators. Daily management

Participants and international cooperation

tasks were performed in each Work Package (WP) under the leadership of the WP manager.

The

The main tasks of the Management Group were

together the leading forest cluster companies,

FuBio

Cellulose

programme

brought

to supervise the progress of the programme with

selected value chain companies in nonwoven

respect to the objectives of the FuBio Cellulose

and staple fibre areas, and public research

programme plan, and to assess the scientific

groups related to chemical pulping technology,

progress and techno-economic feasibility of the

cellulose material science, modelling and

results. The MG had the following members:

simulation and cellulose product applications in Finland. Six companies (seven until 2013)

• Heikki Hassi, Carbatec, until March 2013

and six Finnish universities and research

• Esa Hassinen, UPM-Kymmene (Eeva

institutes participated in the programme. In

Jernström until September 2012)

addition, material demonstration work was also

• Margareta Huldén, Suominen

subcontracted from external partners.

• Ilkka Kilpeläinen, University of Helsinki, Scientific Coordinator

Industrial partners

• Kari Kovasin, Metsä Fibre, Chairman, Industrial Coordinator

• Carbatec, withdrawn 2013 • FIBIC

• Jukka Laakso, Tekes

• Kemira

• Markku Leskelä, FIBIC (Lars Gädda until April

• Metsä Fibre

2012)

• Stora Enso

• Jari Räsänen, Stora Enso

• Suominen

• Kari Saari, Kemira

• UPM-Kymmene

• Anna Suurnäkki, VTT, Programme Manager Research organizations

Dissemination

the

FuBio

Cellulose

• Lappeenranta University of Technology

programme results was achieved with a number

• Tampere University of Technology

of different tools, the most important being

• University of Helsinki

the FIBIC research portal, accessible to the

• University of Oulu

FuBio Cellulose programme participants, and

• VTT Technical Research Centre of Finland

the FIBIC Ltd website open to the wider public

• Åbo Akademi

(http://fibic.fi/programmes/fubio-cellulose).

Both internal and public programme seminars

International collaboration was integral to

were held annually. The public seminars held

the FuBio Cellulose programme. The research

jointly with the FuBio JR2 programme brought

and company networks generated play an

together experts from academic and industrial

important role in the further development of

fields and provided a comprehensive overview

the wood cellulose based value chains and

of the research activities and results of both

the Finnish knowledge base supporting this

FUBIO CELLULOSE PROGRAMME REPORT

development. The programme partners worked

The FuBio Cellulose programme has been

collaboratively with several research groups

closely linked to the FuBio Joint Research 2

from five countries: Germany, Latvia, Poland,

programme, especially in the development of

Portugal, Spain, and Sweden. Close links with

cellulose dissolving ionic liquids. It is also the

the international scientific community will be

basis for the new Advance Cellulose to Novel

maintained and strengthened in the future,

Products (ACel, 2014-2017) programme of FIBIC

particularly in the research areas of cellulose

Ltd. Many of the programme’s researchers

dissolution and regeneration as fibres by novel

have also been involved in other on-going,

methods, chemical modification of cellulose

related national and international projects. This

and cellulose structure characterization.

has ensured active information exchange and

Programme participants have been active in

presenting

programme

Finnish and international research community.

workshops.

FuBio Cellulose research groups participated,

Furthermore, programme results have been and

for example, in the European Community’s 7th

will continue to be published in scientific journals

Framework Programme projects and several

as peer reviewed papers. The programme

COST actions.

conferences

and

results

synergistic knowledge generation among the

international

the

results have also been communicated with the

The FuBio Cellulose programme’s results

value chain companies outside the programme

support industry-driven projects aimed at

consortium. The novel wood cellulose based

developing novel business based on wood

textile fibres produced using the processes

cellulose. Active participation of industrial

developed in FuBio Cellulose drew national

partners within the programme has ensured

attention in 2014 with the presentation of a

effective information flow from research to

dress manufactured from these fibres by design

innovation, thus speeding business development

company Marimekko (see: http://fibic.fi/results).

among the participating companies.

Dissolution of cellulose • New ionic liquid based processes • New water-based processes • Modification

Textiles and nonwovens via spinning regeneration • Regeneration to fibres • Modification • Nonwovens • Modelling cellulose in processing

Cellulose-based chemicals • Cellulose activation • Synthesis routes for cationic polymers • Synthesis of cationic particles • Application & scale-up

New products Absorbents for hygiene products Thermoformable structures Products based on cellulose beads Material demonstration

Markets and economics

Figure 1. FuBio Cellulose programme structure.

FUBIO CELLULOSE PROGRAMME REPORT

IONIC LIQUID-BASED DISSOLUTION AND REGENERATION PROCESSES

C O N TA C T P E R S O N Kristiina Poppius-Levlin, kristiina.poppius-levlin@vtt.fi

PA R T N E R S Aalto University Glocell Lappeenranta University of Technology Metsä Fibre Pöyry Management Consulting Stora Enso University of Helsinki University of Oulu UPM-Kymmene VTT Technical Research Centre of Finland

FUBIO CELLULOSE PROGRAMME REPORT

ABSTRACT The main objectives were to develop novel sustainable ionic liquid-based (IL) solvent systems with the capability to dissolve cellulose pulp of sufficiently high molecular weight to achieve the targeted mechanical fibre properties upon regeneration and to develop commercially viable cellulose staple fibre spinning processes for cellulose/IL solutions. Detailed knowledge of the rheological behaviour of the IL-cellulose solutions, i.e. dopes, is a prerequisite for determination of the viscoelastic properties and further processing of the dopes. Various pulps of different grade and origin were analysed and dissolved in different ILs. Obtained insights and knowledge of dope properties were crucial for the development of the spinning window, i.e. for the prediction of optimal spinning conditions. The hitherto unreported and distillable IL [DBNH][OAc] proved to be an excellent solvent for the production of cellulosic fibres with strength properties significantly higher than those of other man-made commercial fibres. Cellulosic textile fibres were produced with tensile strength properties (>50 cN/tex) exceeding the initial target (â&#x2030;Ľ35 cN/tex). Two demonstration products were manufactured: a scarf made of eucalyptus pulp and a dress (in collaboration with Marimekko) made of Enocell birch dissolving pulp. To assess sustainable chemical modifications of pulp cellulose prior to dissolution, a wide range of chemical reactions were carried out in commercially available and novel, distillable ILs. A sustainable acetylation process of pulp cellulose in distillable IL, i.e. [DBNH][OAc], was of high potential as the mechanical properties of the chemically modified and spun fibres were good. A new cellulose modification method â&#x20AC;&#x201C; cellulose alkoxy carbonylation â&#x20AC;&#x201C; was also developed using ILs as a direct dissolution solvent. In recovery and recycling studies of [emim] [OAc], polymeric ultrafiltration and nanofiltration (NF) membranes as well as a TiO2 ceramic NF membrane gave good retention of organics while not retaining the IL. Reverse osmosis was able to remove some water from IL-water solution ([DBNH][OAc]). In addition, pervaporation showed potential as a method for separating water from IL. Testing with ion-exchange resins showed their potential to remove possible metals from spinning bath solution. The most promising concept for DIL (distillable IL) recovery was based on evaporation and distillation technology.

Keywords: carbonate cellulose, chemical modification, distillable ionic liquid, dissolving pulp, dry-jet wet fibre spinning, fibre, ionic liquids, ion-exchange, membrane separation, purification technology, lyocell process, nanofiltration, pervaporation, reverse osmosis, rheology, solute exclusion, sustainable

FUBIO CELLULOSE PROGRAMME REPORT

1. Work background Increasing global demand for consumer goods

NMMO. Of the relatively few ionic liquids that

is generating robust growth in the textile

have been studied, the majority are imidazolium

fibre market. Total fibre consumption in 2030

based, thus having moderate thermal stability,

is predicted to rise to more than 130 million

and some reactivity towards cellulose via

tonnes, with a predicted share of cellulosic

carbene formation. Moreover, only little progress

fibre of ca. 30%. Paired with the stagnation of

in the formation of cellulosic fibres from IL

cotton production, this will create an annual

solutions has been reported so far.

shortage of 15 million tonnes of cellulosic fibre. This ‘cellulose gap’ opens up new opportunities

A big challenge for IL-based pulp dissolution

for man-made cellulosic fibres. For the Finnish

and regeneration systems is efficient and

forest industry, wood cellulose upgrading to

economical IL recovery. ILs need to be circulated

higher value products fits the strategic target

and reused efficiently. For this purpose, new,

of generating new uses for wood and wood-

easily recyclable ILs also had to be developed

based fibres. The promising market trends

as, for example, distillable ILs were not available.

in textile fibres have aroused interest and activity towards novel, wood cellulose-based regenerated fibre products. Accordingly, one

2. Objectives

of the strong platforms identified as the main outcome from the FuBio1 programme, which

The main objectives were to develop novel

ended in May 2011, was “New knowledge on

sustainable ionic liquid-based (IL) systems

cellulose dissolution in novel, recyclable ionic

with the capability to dissolve cellulose pulp of

liquids”. A further goal was set to convert the

sufficiently high molecular weight necessary

generated competences into market-driven

to achieve the targeted mechanical fibre

value chains.

properties

upon

regeneration.

Chemical

pulp modifications during dissolution were Many attempts have been made to develop

aimed at enhancing water uptake of the

alternative

regenerated fibres. The overall goal was

regenerated

cellulosic

fibre

processes that are competitive or even superior

to the well-established viscose process. So far,

staple fibre spinning processes for cellulose/

develop

commercially

viable

cellulose

only one technology fulfilling these criteria,

IL solutions and to improve the properties

lyocell, is in industrial use. The process is based

(fibrillation and mechanical properties) of

on pulp dissolution in N-methylmorpholine-

the obtained regenerated fibres so that they

N-oxide (NMMO) to form a spinning solution.

can be demonstrated in textile structures. In

However, certain intrinsic properties of NMMO

order to develop an efficient, commercially

render the solvent prone to thermal run-

and environmentally viable IL-based process,

away reaction and cellulose degradation, thus

recycling of ILs is of crucial importance.

necessitating an appropriate stabilizer. This limits the versatility of the process. Approximately a decade ago, ionic liquids were identified as powerful direct cellulose solvents. Their thermal and chemical stability can be utilized to circumvent problems associated with

FUBIO CELLULOSE PROGRAMME REPORT

3. Research approach The overall approach was to develop and

and an extensional rheometer to determine

demonstrate a novel IL-based textile value

the elongational-rheological properties were

chain spanning from wood and chemical pulp

used. The goal was to establish a relationship

production to pulp dissolution in ILs, fibre

between pulp properties (molecular weight

regeneration, yarn spinning and, finally, fabric

distribution), the rheological properties of the

production (Figure 1).

spin dope, and the spinnability. Spinnability describes the extrusion behaviour of the dope

In the commercial lyocell process, pulp is

and the filamentsâ&#x20AC;&#x2122; stability in the air gap when

dissolved

stretched, i.e. extensional stress exerted.

(NMMO)

monohydrate

N-methylmorpholine

N-oxide

(non-derivatizing

solvent) to achieve cellulosic textile fibres.

The chemical stability of cellulose in the IL is important for the final fibre properties and for

To circumvent the problems associated with

the development of a recycling strategy. Thus,

NMMO, the potential of different ionic liquids

respective pulp solutions in [emim][OAc] were

(IL) for the production of man-made cellulosic

tested

fibres was studied.

tests. All properties were compared to NMMO.

with

time-temperature

degradation

Once a basic understanding was established, A commercially available IL, [emim][OAc] (1-ethyl-

other ILs were tested. Besides known cellulose-

3-methylimiadzolium acetate), known to be an

dissolving ILs, promising novel, distillable ILs

excellent cellulose solvent, was used for initial

were developed and their suitability in fibre

trials. Several dissolving pulps were dissolved

spinning was tested. Hence, respective pulp

and the rheological properties of the resulting

solutions were prepared and characterized in

solutions were assessed. An understanding of

detail.

the factors governing the rheological properties of cellulose solution was of great importance

The strategy for chemical modification of

for solution processing. Thus, a classical shear

pulp cellulose in ILs was to modify cellulose

rheometer to assess the viscoelastic properties

to low DS (degree of substitution) in order to

Figure 1. Ioncell-F textile chain â&#x20AC;&#x201C; from wood to garment.

FUBIO CELLULOSE PROGRAMME REPORT

allow disruption of the crystallinity of cellulose

In the functionalization of regenerated fibres,

and hence increase the water absorptivity

the goal was to improve fibre properties, such

of the resulting regenerated fibres. Similar

as to reduce fibre fibrillation, through chemical

incorporation of other alternative functionalities

modification. In recent years, robust, quick, and

besides low DS may also afford novel properties

high fidelity chemical reactions tolerating both

and increased water retention. Therefore, the

water and oxygen have been developed under

research approach was to look for sustainable

the context of click chemistry. Alongside this,

chemical

for

irreversible adsorption of certain polysaccharides,

modification of cellulose in the chosen ionic

such as carboxymethyl cellulose (CMC), is a

liquid for fibre spinning. At the early stages the

well-established

fibre-spinning process was not established, so

concepts can be combined to provide a generic

a wide range of ionic liquids was tested. Many

modular platform. In the first step, modified

types of chemical modification were also tested

polysaccharide chains with clickable functional

to see which ones would be atom efficient, cause

groups were physically adsorbed on the cellulose

minimal degradation and be sustainable. It was

surface. Second step was the actual click reaction,

initially intended that the regenerated cellulose

in which the desired molecule was covalently

properties would guide the development, but

attached to the modified polysaccharide in-situ

this approach proved impractical. Instead, it was

as already adsorbed on the surface.

modification

procedures

phenomenon.

These

two

found to be more effective to examine a wide range of chemistries to see which ones were

To ensure the economic viability of IL-based pulp

suitable and then transfer these to the resource-

dissolution and regeneration systems, ILs need

intensive fibre spinning directly.

to be circulated and reused efficiently. Use of pressure-driven membrane separation processes

In the spinning trials, the commercially available

for purification, recovery and concentration of

ionic liquid [emim][OAc] was chosen as the first

ILs is one potential approach. To examine this

IL to be tested. Different dissolving pulps used

approach, the filterability and tolerance of selected

in the lyocell process were used to benchmark

membranes towards the ILs â&#x20AC;&#x201C; [emim][OAc] and

the first results. Since the formation of a single

distillable [DBNH][OAc] â&#x20AC;&#x201C; were first studied. After

monofilament is more straightforward, this was

identifying suitable membranes, their usability

studied first. Subsequently, other novel volatile

for removing impurities, such as carbohydrates

ILs were implemented. One new IL, [DBNH][OAc]

dissolved during the process, was proved.

(1,5-diazabicyclo(4.3.0)non-5-enium

acetate)

showed excellent spin stability, thus enabling

The efficient removal of water from the ionic

the

multi-filament

liquids used in the cellulose dissolution process

spinning process to be studied. Different pulps

is also a prerequisite for the feasibility of

of lower quality (higher hemicellulose and

the ionic liquid based fibre spinning process.

residual lignin content) were also spun, and the

Pervaporation proved to be a potential energy-

effects of chemical cellulose modification on

efficient separation, purification and recovery

spin stability and fibre properties were studied.

technology for this purpose.

effects

governing

the

A comprehensive set of analytical tools was

employed to shed light on the mechanisms

Preliminary techno-economic screening of

of solution spinning and to characterize the

DIL (distillable ILs) recovery concepts was

resulting fibres not only in terms of their

carried out, including identification of different

mechanical properties but also their (supra-)

recycling concepts and estimation of the main

molecular structure.

production costs of the concepts.

FUBIO CELLULOSE PROGRAMME REPORT

4. Results

and DBN-based distillable ionic liquids, the propionate versions were also briefly studied.

4.1 Programme pulps and ILs 4.2 Dope properties Pulps

Three different common pulps were selected for

Detailed knowledge of the rheological behaviour

the programme in order to be able to compare

of the IL-cellulose solution, i.e. dopes, is a

results between different partners in the

prerequisite for determination of viscoelastic

programme. Additional pulps were also used in

properties and for further processing of the

different programme activities as necessary. The

dopes. Various cellulosic solutes (pulps with

programme pulps were acquired, characterized

different cellulose content and intrinsic viscosity

with a number of methods and delivered to all

levels) were used for dope preparation. Figure

partners in the programme (FBC-pulp1: Domsjรถ

3 shows the complex viscosities and dynamic

softwood sulfite pulp; FBC-pulp2: Eucalyptus

moduli of three pulps in [emim][OAc]. Although

urograndis pre-hydrolysis kraft pulp, Bahia

the softwood and beech sulfite pulps have

Solucell; and FBC-pulp3: Borregaard spruce

similar intrinsic viscosity values (540 and 520

sulfite pulp) (Table 1).

ml/g, respectively) their respective IL-solutions differ significantly. On the other hand, solutions

Ionic liquids (ILs)

of the eucalyptus pre-hydrolysis kraft pulp (FBC-

The main ionic liquids used in the programme

pulp2) and beech sulfite pulp are similar in terms

are shown in Table 2 and the structures are

of their viscoelastic properties although the pulp

presented in Figure 2. In the case of the TMG

viscosities were different.

Table 1. Programme pulps and their properties. FBC-pulp1, Domsjรถ

FBC-pulp2, Bahia, HW/

FBC-pulp3, Borregaard,

Sulfite, SW/Spruce-Pine

Euca, PHK

SW/Spruce Sulfite

Viscosity, ml/g

520

470

1520

Kappa no

0.48

0.3

4.1

Glucan, rel%

89.8

95.8

90.8

1.4

2.6

3.6

2.1

Mn, g/mol (SEC)

47 600

34 300

32 100

Mw, g/mol (SEC)

405 000

358 000

1 307 000

8.5

10.4

40.7

Xylan, rel% Mannan, rel%

PD (Mw/Mn) (SEC) Mn, g/mol (MALLS)

41 300

62 900

67 200

Mw, g/mol (MALLS)

530 500

196 400

792 000

4.1

3.7

7.3

DP>2000, w%

14.6

58.7

PD (Mw/Mn) (MALLS)

12.9

3.1

11.8

DP<100, w%

Crystallinity, %

Fibrils, nm (Lateral

4.2

4.8

14.2

dimens.) Aggregates, nm

FUBIO CELLULOSE PROGRAMME REPORT

Table 2. Main ILs used in the programme. Name of IL

Abbreviation

Comments, main uses in the programme

1-ethyl-3-methylimidazolium acetate

[emim][OAc]]

For dope property and rheological studies; benchmark literature IL

1-ethyl-3-methylimidazolium methylhydrogenphosphonate

[emim][MeHPO3]

For IL phosphonate anionization of cellulose

N,N,N,N-tetramethylguanidinium acetate

[TMGH][OAc]

1st generation distillable IL

1,5-diazabicyclo(4.3.0)non-5-enium acetate

[DBNH][OAc]

Dope property studies; current fibre-spinning IL

1-methyl-1,5-diazabicyclo(4.3.0)non-5-enium dimethylphosphate

[mDBN][Me2PO4]

Alternative low-viscosity nondistillable structure for rheology testing

methyltrioctylphosphonium acetate

[P8881][OAc]

Phase-separable ionic liquid

Figure 2. Main ionic liquids studied during the programme.

Figure 3. Complex viscosity and dynamic moduli of FBC-pulp2 (Euca PHK pulp, 470 ml/g) (blue); FBC-pulp1 (DomsjĂś 540 ml/g) (black), beech sulfite pulp (Lenzing, 520 ml/g) (red) in [emim]OAc (all solutions 10 wt%, at 60Â°C).

FUBIO CELLULOSE PROGRAMME REPORT

It is known that cellulose undergoes degradation

be assessed without laborious regeneration of

in IL solutions. To study the stability in detail, a 10

the cellulose. Extensional studies show a very

wt-% solution of eucalyptus pre-hydrolysis kraft

sensitive response in elongational relaxation

pulp (FBC-pulp2) in [emim][OAc] was prepared

time to cellulose degradation. This is important

and then stored at different temperatures

for predicting the spinnability of various dopes.

for various periods. The solutions were then

It should be noted that substantial degradation

characterized in terms of rotational shear and

already occurs during the dissolution process.

extensional viscosity before the cellulose was

Thus, the effect of propyl galate (PG) as a stabilizer

regenerated and its intrinsic viscosity measured.

– as used in lyocell solutions – was studied. The addition of PG reduced degradation substantially.

Figure 4 (a) reveals substantial degradation of cellulose at temperatures of 90°C or higher.

In order to study the influence of molecular

However, the cellulose is not affected when

weight distribution on the spinnability of the

stored at 60°C for 24 h. The cellulose degradation

resulting dope, different (native and degraded)

is reflected in the viscoelastic properties of the

pulps were mixed and dissolved in [emim][OAc]

respective solutions (Figure 4 b) and can thus

(Figure 5.) Only Blend 2 showed good spinnability.

Figure 4. DP of the regenerated cellulose of IL-cellulose solutions stored at different temperatures as a function of storage time (a) and Zero shear viscosity from respective solutions (b); DP calculated from the intrinsic Cuen viscosity.

Figure 5. Molecular weight distribution (a) and zero-shear viscosity (full symbols) and crossover moduli (open symbols) as a function of COP-angular frequency (b).

FUBIO CELLULOSE PROGRAMME REPORT

The zero-shear viscosity and the angular frequency

Using recyclable IL systems, [DBNH][OAc] and

and dynamic modulus of the crossover point (COP)

[P8881][OAc] gave better product quality and

of a cellulose-IL solution need to be within specific

cleanliness than [emim][OAc]. The reaction is,

ranges to obtain successful spinning. A zero-shear

however, still not very atom-efficient (10 eq of

viscosity between 27000 and 30000 Pa·s and a

epoxide used) and cellulose and ionic liquid were

crossover point between 0.8 and 1.2 s-1 and 3000

found to degrade to some extent under the used

and 5500 Pa, respectively, seem to be required.

conditions, even in the presence of catalysts.

Furthermore, it seems that the spinnability of a cellulose-IL solution is very sensitive to the high

Cellulose alkoxycarbonylation using

molecular weight fraction of the cellulosic solute

dialkylcarbonates

and to the polydispersity index (PDI). For successful

New cellulose derivatives – cellulose alkyl

spinning, a high molecular weight content greater

(methyl or ethyl) carbonates – were successfully

than 20% and a PDI higher than 3 appeared to be

prepared (Figure 7). The optimum procedure for

favourable.

their preparation is by dissolution of cellulose in 10 wt% DMSO:[P8881][OAc] (phase-separable

Main achievements

ionic liquid electrolyte) and using dimethyl or

• Obtained insights and knowledge of dope

diethylcarbonate. Reaction also succeeded

properties were crucial for the development

in [P8881][OAc] and [emim][OAc]. Products with

of the spinning window, i.e. prediction of

a DS (degree of substitution) up to 1 were

optimum spinning conditions.

obtained. However, [DBNH][OAc] did not give

• Various pulps of different grade and origin

the desired product.

were analysed and dissolved in ionic liquids. Even low-grade pulps were successfully

See-through and flexible cellulose methyl-

spun in appropriate spinning conditions.

carbonate films were successfully prepared by solvent casting from pyridine.

4.3 Chemical modification of pulp cellulose in ILs

Corey-Kim oxidation

Corey-Kim oxidation is a method of selectively In examining the chemical modification of pulp

converting alcohols to aldehydes or ketones.

cellulose in ILs, several sustainable strategies

The reaction was confirmed to occur in LiCl/

were developed with the aim of imparting

DMA (lithium chloride / dimethyl acetamide), but

novel properties to the regenerated fibres,

overall the amounts of cellulose soluble at the low

such as increased water absorptivity, reduced

temperatures required by the method, combined

fibrillation or fire-resistance.

with the inability to recycle all reagents made it unlikely that this procedure could be transferred to the spinning dopes. Despite this being a novel

Cellulose etherification with epoxides

typical

reaction

scheme

for

cellulose

etherification, i.e. preparation of hydroxypropyl

and unpublished reaction in the literature, the decision was made not to continue this work.

cellulose, is shown in Figure 6. Cellulose (typically 5-10% w/w) was dissolved in different

Cellulose esterification using anhydrides or

ILs, typically [emim][OAc], [DBNH][OAc] and

esters

compositions of DMSO and [P8881][OAc] (0-

Esterification

40% w/w DMSO). After dissolution, propylene

anhydrides and esters was highly successful. A

oxide was added (10 eq) and the mixtures were

sustainable method of cellulose acetylation was

heated for a set time period.

developed. Fibres have been spun from these

cellulose

with

carboxylic

dopes and the initial results look promising.

FUBIO CELLULOSE PROGRAMME REPORT

Figure 6. Typical cellulose etherification conditions and reaction in DMSO:[P8881][OAc].

Figure 7. Scheme for preparation of cellulose alkyl carbonates using dimethyl carbonate (DMC) or diethylcarbonate (DEC) in [P8881][OAc]:DMSO solutions.

Main achievements

• Several new, potential strategies for chemical modification of pulp cellulose in different ILs were developed. • Esterification of cellulose in ILs with carboxylic anhydrides and esters was very successful. Fibres have been spun from the dopes and the initial results look promising. • Transesterification of a phosphonate ionic liquid with cellulose produced water-soluble, film-castable and fire-retardant cellulose. Unfunctionalized cellulose was found to be regenerated by dispersing in dilute acid, resulting in a novel cellulose regeneration process. • Alkoxycarbonylation of cellulose using the green reagents dimethyl and diethylcarbonate succeeded in ionic liquids.

FUBIO CELLULOSE PROGRAMME REPORT

4.4 Cellulose textile fibres via spinning regeneration

stage conical diminution (first cone 60°, second cone 10°) and a spin capillary aspect ratio of L/D = 0.2 showed no melt fracture. Fibres spun

Production of staple fibres – Ioncell-F process

from eucalyptus pre-hydrolysis kraft pulp

A novel process for producing staple fibres from

(FBC-pulp2)-[DBNH][OAc] solutions and their

ILs was developed and named Ioncell-F(iber)

extraordinarily high draw ratio are illustrated

in analogy to the lyocell process. Staple fibres

in Figure 8. Mechanical properties of Ioncell

from various pulps were produced successfully

fibres are significantly better than those of other

using a distillable IL ([DBNH][OAc]) as solvent.

man-made cellulosic fibres, such as viscose,

Optimized multi-hole spinnerets with a two-

modal and lyocell (Tencel) (Figure 9).

Figure 8. Fibres spun from FBC-pulp2 (eucalyptus PHK)-[DBNH][OAc] solutions (a). Linear density (titer) and tensile strength (tenacity) of fibres spun from FBC-pulp2-[DBNH][OAc] solutions as a function of draw (b).

Figure 9. Mechanical properties of Ioncell fibres in comparison to other man-made cellulosic fibres.

FUBIO CELLULOSE PROGRAMME REPORT

Fibre analysis

Standard

linear

orientation that was high and increasing with the

density (titer) and tensile strength (tenacity)

fibre

properties

such

draw ratio. The fibres showed a typical fibrillar

were measured on a routine basis. In addition,

morphology (Figure 10, a). Also, determination of

orientation and crystallinity were measured

the molecular weight of the cellulose before and

via optical birefringence and X-ray analyses,

after spinning showed that there is no significant

respectively. Morphology was assessed by means

degradation during the spinning process (Figure

of SEM. Similar to lyocell fibres, the Ioncell fibres

10, b). This is important not only for the fibre

showed high tenacity values that were retained

properties but also regarding purification and

under wet conditions. Crystalline and total

recycling of the IL.

Figure 10. SEM (a) and GPC (b) analysis of fibres spun from FBC-pulp2 (eucalyptus PHK)-[DBNH][OAc].

FUBIO CELLULOSE PROGRAMME REPORT

Demonstrations of textile production

The official presentation of the scarf (Figure

demonstrate the applicability of the fibres for

demonstration

run

was

performed

11g) at the FIBIC annual seminar (autumn 2013)

textile production. Ca. 20 litres of [DBNH][OAc]

attracted the attention of a Finnish textile and

were synthesized at Helsinki University and

design company Marimekko, who expressed

approximately 300 g of Ioncell staple fibres

an interest in jointly producing a full garment.

spun at Aalto University. Together with the

Fibres from birch dissolving pulp (Stora Enso)

Department of Design (School of Arts, Design

were subsequently similarly processed to

and Architecture, Aalto University) the fibres

produce a dress (Figure 12), which was exhibited

were ring spun to a yarn at the Swedish School

at Marimekkoâ&#x20AC;&#x2122;s Autumn and Winter Fashion

of Textiles (University of BorĂĽs, Sweden), dyed

show (Helsinki railway station, March 2014).

and flat-bed knitted (Figure 11). Fibre and yarn

This spin-off project of the FuBio Cellulose

properties are summarized in Table 3. Both

programme is summarized in a video available

the IL-fibres and the IL-yarns have significantly

online (http://youtu.be/AGFDPyzN1C8).

higher tenacity than commercial viscose fibres.

Figure 11. Process steps during yarn manufacture and the final knitted product: a) carding of [DBNH][OAc]spun staple fibres; b) sliver feeding to the drafting machine; c) preparing the roving; d) feeding the roving; e) ring spinning; f) plying; g) flat-bed knitted scarf.

FUBIO CELLULOSE PROGRAMME REPORT

yarn

fibre

Table 3. Properties of yarns spun from [DBNH][OAc] and commercial viscose fibres. [DBNH][OAc]

viscose

linear density (dtex)

1.9

1.5

dry tenacity (cN/tex)

elongation (%)

9.4

22.5

fibre length (mm)

finish

yes

linear density (tex)

54.3

62.7

tenacity (cN/tex)

34.4

17.3

elongation (%)

7.4

18.2

CV (%)

13.6

9.1

Figure 12. Marimekkoâ&#x20AC;&#x2122;s multi-functional dress produced from 100% Ioncell fibre (birch).

FUBIO CELLULOSE PROGRAMME REPORT

Structure formation process

Extensional rheology experiments have thus

A better understanding of the effects and

been conducted by means of a Capillary

factors governing the structure formation of the

Break-up Extensional Rheometer (CaBER) to

cellulosic fibre, i.e. the transition from solution

characterize the air gap phenomena. Once the

to solid state, is needed to tailor and improve

filament enters the spin bath, a complex solvent

the solvent-based spinning process. Several

exchange leads to the coagulation of the

stages in the spinning process influence the

cellulose and formation of the solid fibre. The

final (supra-)molecular structure of the cellulose

solvent exchange in the spin bath is suspected

polymer chains in the fibre. Shear stress in the

to proceed via spinodal decomposition, which

spin capillary causes pre-orientation of the

largely preserves the molecular orientation

polymers in solution. Thus, each prepared dope

created in the spin capillary and air gap.

was subjected to a routine shear rheological

Batch experiments were conducted to study

characterization. When the liquid filament

the diffusion kinetics of the solvent and anti-

enters the air gap, the shear stress is released

solvent. Upon solvent exchange, the water

instantaneously and the polymer chains tend

content in the filament increases gradually

to re-assume a random-coil formation which

from the surface while, concomitantly, the

leads to die-swell. This is counteracted by

solvent level decreases. This causes a radial

the draw acting on the filament. The exerted

gradient where the transition from filament

elongational stress causes a further orientation

to fibre passes through various gel-states

of the cellulose chains.

(Figure 13). These gel states were assessed in

Figure 13. Cut through a simulated filament in the coagulation bath. The graphs show the solvent and water content, respectively, as the coagulation proceeds. The solvent content decreases from blue to red. X-axis shows the radial distribution, y-axis along the fibre.

FUBIO CELLULOSE PROGRAMME REPORT

terms of their elastic strength and moduli in

also small (lab-scale) amounts of IL and thus gain

order to determine the weakest point of the

more flexibility, a small piston spinning unit (KS15)

filament in the spin bath. It was shown that the

was integrated into the existing spinning line,

structure formation can differ markedly due to

thus enabling full use of all previously installed

different diffusion constants and gel strengths

equipment (Figure 14). The piston speed was

of different ILs.

reduced accordingly to create the same shear stress conditions generated in the bigger unit

New ILs were constantly tested for their suitability

(KS42). The characteristics are summarized in

as fibre spinning solvents. In order to process

Table 4.

Figure 14. KS15 (left) and KS42 (right) piston spinning unit.

Table 4. Specification of spinning units. KS42

KS15

piston diameter

42 mm

15 mm

cylinder volume

500 ml

17 ml

extrusion velocity range

0.4 â&#x20AC;&#x201C; 5.0 ml/min

0.007 â&#x20AC;&#x201C; 0.06 ml/min

FUBIO CELLULOSE PROGRAMME REPORT

Main achievements

commercial triazine crosslinker (Figure 15).

• [DBNH][OAc] proved an excellent solvent for

The fibrillation index was reduced from 2.5

cellulose fibre spinning.

to 1.0. Similar positive effects of crosslinking

• The mechanical properties of Ioncell fibres

are also expected with other fibre types.

are significantly higher than those of other

Fibre

man-made cellulosic fibres.

the adsorption of pre-modified CMC and

• The chemical stability of the cellulose and

crosslinking

chemistries

based

click chemistry and those with commercial

mechanical properties of the resulting

crosslinking

fibres clearly exceeded the goals set at the

dichloro-1,3,5-triazine are shown in Figure 16.

agent

2-sodiumhydroxy-4,6-

beginning of the programme. Cellulosic textile fibres were produced with tensile

Main achievements

strength properties (>50 cN/tex) exceeding

• Pre-modified CMCs were irreversibly adsorbed

the initial target (≥35 cN/tex).

onto regenerated cellulose fibres. Further

• Different dissolving pulps were spun

functionalization of cellulose fibres was

successfully with only minimal difference

demonstrated using click chemistry reaction.

in final mechanical properties. Paper grade pulp was converted into textile fibres with

• Fibre fibrillation was reduced using a clickchemistry based crosslinker.

tenacity values of 48 cN/tex.

4.6 Recovery of ionic liquids

• Two demonstration products were manufactured: a scarf made of eucalyptus and a dress (in collaboration with

Efficient recovery of ILs in IL-based solution

Marimekko) made of Enocell birch dissolving

and spinning processes is a prerequisite for

pulp. The products were presented at the

an environmentally and economically feasible

FIBIC Annual Seminar November 2013 and at

process.

Marimekko’s autumn and winter collection fashion show (March 2014).

Pressure-driven membrane separations

Different

4.5 Functionalization of regenerated cellulose fibres

(ultrafiltration)

and

(nanofiltration) membranes were screened and tested for filtration of IL-water solutions and for removal of impurities, i.e. dissolved

The aim of the chemical functionalization

material, during the process.

of regenerated and spun fibres task was to give the fibres more added-value and better

Model solution (galactoglucomannan, GGM,

properties, such as reduced fibre fibrillation.

representing carbohydrate impurities in the spinning bath) filtration tests were conducted in

Crosslinking of spun fibres

cross-flow mode with a polymeric ultrafiltration

Due to the high orientation of Tencel (lyocell)

membrane (GM by GE Waters, USA) and a

fibres, the fibres have a high tendency for

ceramic nanofiltration membrane (Inopor®nano

fibrillation. The degree of fibrillation can be

by Inopor® GmbH, Germany) (Figure 17). With

taken as a direct indication of the abrasion

the ceramic membrane the flux was slightly

resistance of the fibre. Results using click

better than that with the GM membrane and

chemistry for crosslinking Tencel reference

the model compound retention was also better.

fibres to reduce the unwanted fibrillation

The normalized fluxes were more or less the

tendency of highly oriented fibres showed

same at the beginning of testing (around 13 L/

promising

m2hbar) but remained higher with the ceramic

results

similar

those

FUBIO CELLULOSE PROGRAMME REPORT

Figure 15. Fibrillation indexes of unmodified and crosslinked Tencel (commercial lyocell) fibres after mechanical abrasion test (ball bearing method). HO O OH

HO R1O

OH O

R1O

OR 1

R1O O

OR 1

R2O O

HO O

OR 1

N O N

R2O

O R2O

OR 2 O

HO O

O OR 2

R2O O

OR OH 2

HO O

R2O

O O

R1O

OH R O 1 O

HO O

R 1 =H, CH 2 COONa or azide group

R 2 =H, CH 2 COONa or alkyne group

O HO

O O

OR 2

HO O

O OH

oup

roup

b)O

O OH

HO O

O OH

N O

OH O

O OR 1

O OH

OH OH

O O OH

Figure 16. Chemical crosslinking via triazole ring (click chemistry) (a) and chemical crosslinking via triazine ring (commercial crosslinker) (b).

FUBIO CELLULOSE PROGRAMME REPORT

Figure 17. Filtration with the GM UF membrane (cross flow)(a); [emim][OAc]] 20w%/H2O 80w% + 1 g/L GGM, 7.5 bar, 25°C, initial feed volume 2.0 L, A = 100 cm2 and cross-flow velocity 1.7 m/s. Filtration with ceramic NF membrane (Inopore®nano TiO2) (cross-flow)(b); [emim][OAc]] 20w%/H2O 80 w% + ≈1 g/L GGM, 2.0 bar, 25°C, initial feed volume 2.0 L, A = 660 cm2 and cross-flow velocity 0.3 m.

membrane (10 L/m2hbar with the ceramic

is not retained, i.e., the solution can be purified

membrane and 7 L/m hbar with the polymeric

from organic contaminants). UF (ultrafiltration)

membrane, see Figure 17). This may be due to

can be used as a preceding step, although it will

more fouling of the GM membrane during the

not remove smaller molecules.

filter test. The filtration trial with real spinning bath solution It is possible to remove polysaccharides

was done with an NF 270 membrane in cross-

almost entirely and monosaccharides (glucose)

flow. Sugars in the spinning bath solution were

partially (more than 50%) by NF (nanofiltration)

retained totally, but the IL was also 90% retained.

if the IL concentration is high enough (thus IL

FUBIO CELLULOSE PROGRAMME REPORT

Reverse osmosis

The reverse osmosis (RO) process can remove

1) [emim][OAc]]

water from the spinning bath solution up to

• PVA-TiO2 and PVA-PDMS membranes

about 30 wt%. This limit derives from the

from HZG (Helmholtz-Zentrum Geesthacht)

osmotic pressure of the IL/water solution,

tolerated [emim][OAc]] and were able

which would require even higher pressures

to separate water from the [emim]OAc/

to be used to overcome the osmotic pressure

water solution (90 wt%/10 wt%) in the PV

resistance. In this study the highest operating

experiments.

pressure was 50 bar. A 15 wt% solution of IL ([DBNH][OAc]) in water would give about 40

2) [mDBN][Me2PO4]

bar osmotic pressure, theoretically. Pressures

• None of the seven studied pervaporation

above 50 bar would remove more water, but

membranes tolerated [mDBN][Me2PO4].

would be economically unfeasible due to energy consumption. A 30 wt% solution would

3) [DBNH][CO2Et]

give about 80 bar osmotic pressure (at 25°C

• PVA-TiO2 and PVA-PDMS membranes

and if IL is dissociated completely) which is,

from HZG and PERVAP 2255-30 membrane

however, already close to the recommended

from Sulzer tolerated [DBNH][CO2Et] in the

upper limits for RO membranes.

preliminary experiments. • PVA-TiO2 and PVA-PDMS membranes were

Metal removal by ion-exchange resins

able to separate water from the [DBNH]

A simple IEX (ion exchange) test to remove

[CO2Et] / water solution (90 wt%/10 wt%) in

metals from the model spinning bath solution

the PV experiments.

gave very positive results. SAC (Strong Acid Cation) exchange resin removed magnesium

DIL (distillable IL) recovery concepts

almost totally, whereas WAC (Weak Acid Cation)

Twelve DIL recovery concepts were identified

exchange resin showed significantly inferior

together with the research groups. Preliminary

performance.

production cost estimates of these concepts were analysed in six scenarios. In summary,

Recovery of ionic liquids by pervaporation

energy and capital costs dominated the costs

Several polymeric membranes were tested

in all concepts, while evaporation of water

for the recycling of ionic liquids used in the

made up the bulk of the energy costs. The

cellulose dissolution process. Pervaporation

lowest production costs were achieved in the

(PV) tests with tri-1,5-diazabicyclo propionate

concepts where IL was purified by distillation,

([DBNH][CO2Et]) showed that PVA-TiO2 and

followed by concepts with flotation and ion

PVA-PDMS membranes were able to separate

exchange based purification.

water from the [DBNH][CO2Et] / water solution. Also

1-ethyl-3-

methylimidazolium

acetate

[DBNH][OAc] hydrolysis and recycling

([emim][OAc]]) showed high selectivity to water

[DBNH][OAc] as the favoured distillable ionic

permeation with PVA-TiO2 and PVA-PDMS

liquid for Ioncell fibre spinning has a certain

membranes. The membranes did not, however,

degree of hydrolytic instability. This is dependent

tolerate mDBN-dimethyl phosphate ([mDBN]

on temperature and water content. IL hydrolysis

[Me2PO4]). In summary:

is faster as the water content decreases and temperature increases. Successive cycles of pulp dissolution and regeneration in a batch reactor were undertaken to determine how

FUBIO CELLULOSE PROGRAMME REPORT

many times the IL can be recycled whilst still

- Reverse osmosis (RO) was able to remove

maintaining its cellulose-dissolving capability.

some water from IL-water solution ([DBNH]

It was determined that under batch dissolution, regeneration and drying conditions the IL could

[OAc]). - Ion Exchange Resin (IEX) was highly

be reused seven times until the hydrolysis

effective at removing metals from IL-water

product reached a level preventing dissolution

solution

(15 mol% hydrolysis product). As compared to a dynamic process, the regeneration and recycling conditions under batch dissolution

• Pervaporation was shown to be a sufficient method for separating water from IL. • [DBNH][OAc] can be reused 7 times. A

conditions allow much longer solvent residence

certain degree of hydrolytic instability is

times in contact with hot surfaces. Therefore,

overcome by a recycling step that converts

hydrolysis was greatly increased. Nevertheless, the hydrolysis product needs to be converted

the hydrolysis products back to the IL. • The most promising concept for DIL

back to ionic liquid, and this requires a recycling

(distillable IL) recovery was based on

step. This was demonstrated to be possible

evaporation and distillation technology.

by preparing the hydrolysis product and converting it back to the IL in the presence of excess DBN and Amberlyst 15 (superacidic

4.7 Techno-economic modelling of Ioncell fibres

resin). This enabled recovery of [DBNH][OAc] (Figure 18), avoiding irreversible decomposition

The

to the amide decomposition product.

evaluations were to facilitate communication

objectives

between

researchers

the and

techno-economic decision-making

Main achievements

companies, to identify central R&D needs during

• It was proven that membrane filtration

the course of the programme, and to provide

and ion exchange resin processes can be

recommendations for further research. The

used as building blocks for solvent recovery

techno-economic modelling of Ioncell-F fibres

and recycling in novel cellulose processing

analysed the production of cellulosic stable fibres

techniques that utilize ILs.

using dissolution and regeneration technology

- Nanofiltration (NF) membranes were

based on novel ionic liquids developed at the

effective at separating dissolved organics

University of Helsinki. Lyocell staple fibre was

from IL-water solutions while not retaining IL

selected as a reference both for the production

([emim][OAc]).

concept and end-use market.

Figure 18. Hydrolysis and reconversion to [DBNH][OAc] under suitable experimental conditions.

FUBIO CELLULOSE PROGRAMME REPORT

The techno-economic modelling compared

Steam consumption in the SPINCELL process

two ionic liquid based processes with the

was about 16% higher than the corresponding

commercial NMMO process (Table 5). SPINCELL

NMMO

process concept included Ioncell-F process and

INTEGRATED process was somewhat higher

ionic liquid recycling process using dissolving

compared to SPINCELL. Optimization of ionic

pulp and INTEGRATED process concept had kraft

liquid recovery could lead to lower production

pulp as feedstock and the same ionic liquid to

costs via energy and IL savings. A block-flow

function both in hemicellulose dissolution and

diagram of the IL-based stable fibre production

fibre spinning. NMMO refers to the dissolution

process is illustrated in Figure 19.

process.

consumption

the

solvent used in the process of producing lyocell fibres from dissolving pulp feedstock.

Of all the techno-economic modelling cases studied in the FuBio Cellulose programme,

All studied cases showed good profitability at

the Ioncell fibres received the highest scores

a lyocell staple fibre price above 2 000 EUR/t.

in the qualitative opportunity assessment.

Table 5. Studied process concepts. Process concept

Feedstock

Solvent

SPINCELL

Dissolving pulp

[DBNH][OAc]

INTEGRATED

Kraft pulp

[DBNH][OAc]

NMMO

Dissolving pulp

NMMO

Dissolving Pulp DC 90% Makeup IL

Premixing

Thin film evaporation

IL Distillation

Impurities Filtering Evaporation Spinning

IL recovery Washing

Finishing

Drying

Water

Fibres Figure 19. Block-flow diagram of the IL-based staple fibre production process

FUBIO CELLULOSE PROGRAMME REPORT

Market opportunities were seen as promising,

whether the fibre producer should use kraft

with a large global market, increasing demand

or dissolving pulp as feedstock. The type and

for man-made cellulosic fibres and excellent

efficiency of the recycling concept has a great

product qualities recorded. However, technical

impact on total production costs, and thus

feasibility

with

should be studied as a top priority. Similarly, the

several uncertainties related to ionic liquid

maximum concentration of impurities in ionic

performance, recyclability and availability.

liquids should be analysed in order to define

The strengths and weaknesses of Ioncell fibre

the required level of IL purification, and thus

production are summarized in a SWOT analysis

purification costs.

still

remains

question

in Figure 20. Based on the techno-economic assessment, the key recommendations for further Ioncell fibre

5. Exploitation plan and impact of the results

research are related to ionic liquid preparation and recycling and the impact of various

Finland has a long tradition in the pulp and

impurities on the spinning process. In developing

paper industry. The importance of the wood

novel ionic liquids, researchers should take into

sector to the Finnish economy is reflected in the

account the industrial-scale availability and

multitude of university faculties that belong to

price of applied reagents. If the reagents are not

the leading institutes of wood technology and

commercially available, the complexity of the

chemistry worldwide. Industrial and academic

chemical synthesis to produce such chemicals

cooperation in the Finnish wood sector is truly

should

same

outstanding, providing the perfect foundation

ionic liquid is suitable for both hemicellulose

for cutting-edge research and innovative

dissolution and fibre spinning is likely to define

products. With the pressure of globalization

evaluated.

Whether

the

Helpful to achieving business success

Harmful to achieving business success

Process related

STRENGTHS • Excellent fibre product quality • Large market and growing demand of manmade cellulosic fibres

WEAKNESSES • Process concept is not yet demonstrated Ionic liquid performance and availability still on a vague basis • Ionic liquid recyclability remains a question • No clear cost advantages foreseen compared to commercial NMMO process

Business environment related

OPPORTUNITIES • Promising production economics • Political support for env. sustainable and safe fibres and production processes is very strong • Integration to pulp mill seems feasible with mutual benefits • Flexible product line with opportunities for various raw materials and product specs. • Ionic liquid screening is still at early stage. Even more promising solvents may be found.

THREATS • Price competitiveness against lyocell in niche applications and against viscose, cotton and other fibres in bulk textile end-uses • Market entry may be difficult due to close market with only few large players

Figure 20. SWOT analysis of textile fibre production via ionic liquids.

FUBIO CELLULOSE PROGRAMME REPORT

and the accompanying shift of big production sites

towards

the

southern

6. Networking

hemisphere

(especially South America, Indonesia and

The research was carried out jointly by

China), the need for new specialized products

Aalto

is urgent. The market for cellulosic fibres is

Lappeenranta, University of Helsinki, University

growing fast due to rapidly industrializing

of Oulu and VTT. Table 6 presents both the

nations, offering new possibilities for Finnish

research partners and industrial partners and

wood-based industry. The knowledge created

their roles in the programme.

University,

Technical

University

by this project opens new opportunities to utilize a broad spectrum of different grade

Aalto University has initiated collaboration

pulps for fibre spinning, enabling raw material

with the Department of Chemical Engineering,

costs to be saved and energy consumption in

University of Porto, in elongational viscosity of

subsequent process steps to be reduced. This

cellulose-IL solutions. The University of Helsinki

increases the economic feasibility and reduces

has collaborated with the University of Santiago

the environmental impact of the entire process.

in the development of analytics related to

Finnish companies are well positioned to take

recyclable ionic liquids. The University of Oulu

a leading role in the biorefinery concept. Stora

has collaborated with the Membrane Separation

Enso has already taken a lead by starting

Processes Group of the Chemistry Faculty at

dissolving pulp production at its Enocell plant

Nicolaus Copernicus University (TorĂşn, Poland)

in Uimaharju.

in the form of researcher exchanges in the area of pervaporation theory and research.

The successful production of textile fibres from local biomass resources has attracted the interest of Finnish textile and design companies and has already led to close collaboration with the leading Marimekko brand. The developed generic methodology for the chemical

functionalization

regenerated

fibres showed potential, and is expected to gain the attention of industrial viscose producers. However, the method has not yet reached the exploitation stage and further work is needed to gather additional data and to understand the full potential and feasibility of the new technique. The ability to use membranes in ILs recovery is important when considering the use of ILs in cellulose dissolution processes. Pervaporation offers a potential energy-efficient separation, purification

and

recovery

technology

for

biorefinery that can bring financial savings and competitiveness to producers. This finding is also of benefit to other industries using ILs as solvents.

FUBIO CELLULOSE PROGRAMME REPORT

Table 6. Partner organizations and their roles. Partner

Role

Aalto University

FPT: Pulp analyses, rheological characterizations

- Forest Products Technology (FPT)

of spinning dopes. IL fibre spinning. Pulp and fibre

- Biotechnology and Chemical Technology (BCT)

modification. BCT: Modelling of ionic liquid hydrolysis kinetics

Glocell

Quantitative economic modelling

Lappeenranta University of Technology

Membrane filtrations

- Separation Technology Metsä Fibre

Industrial tutor. Defining, steering and providing competence for the modelling. Providing industrial view insight to techno-economic assessments

Pöyry Management Consulting

Market study. Economic feasibility modelling. Business potential evaluation

Stora Enso

Industrial tutor. Providing industrial insight to technoeconomic assessments

University of Helsinki - Organic Chemistry

• Preparation of large-scale ionic liquid samples (for Aalto spinning trials, for UO for pervaporation and VLE studies, for LUT membrane purification studies) • Chemical modifications of cellulose in ILs • Designing optimal dope modification procedures in cooperation with Aalto • Understanding IL recyclability in cooperation with Aalto and VTT

University of Oulu

• Pervaporation studies

- Mass and Heat Transfer Process

• Role of pervaporation in cellulose dissolution and regeneration processes

UPM-Kymmene

Industrial tutor. Providing industrial insight to technoeconomic assessments

VTT

• Molar mass analyses • Techno-economic screening of DIL (distillable ionic liquid) recovery concepts • Process modelling, ionic liquid based processes

FUBIO CELLULOSE PROGRAMME REPORT

7. Publications and reports Publications:

Hauru, L. K. J., Hummel, M., Michud, A., Asaadi, S. and Sixta H. High-strength (870

García, V., Valkama, H., Sliz, R., King, A.,

mpa) cellulose filament spun from ionic liquid.

Myllylä, R., Kilpeläinen, I., Riitta L. and Keiski,

Proceedings

R.L. Pervaporation recovery of [AMIM]Cl during

International

Textile

wood dissolution; effect of [AMIM]Cl properties

Germany, 28th-29th November 2013.

the

7th

Aachen-Dresden

Conference,

Aachen,

on the membrane performance, Journal of Membrane Science, 2013, Vol. 444:9-15.

Hummel, M., Hauru, L. K. J., Michud, A. and Sixta, H. Mechanistic studies on the

Hauru, L. K. J., Hummel, M., Michud, A. and

regeneration of cellulose from ionic liquid

Sixta, H. Dry jet-wet spinning of strong cellulose

solutions. Proceedings of the 12th European

filaments from ionic liquid solution. Cellulose,

Workshop on Lignocellulosics and Pulp, Espoo,

2014. DOI: 10.1007/s10570-014-0414-0

Finland, 27th-30th August 2012, pp. 284-287.

Hummel, M., Michud, A., Tanttu, M., Asaadi,

Michud, A., Arnoul-Jarriault, B., Hummel, M.

S., Ma, Y., Hauru, L. K. J., Parviainen, A.,

and Sixta, H. Influence of molecular mass

King, A. W. T., Kilpeläinen, I. and Sixta, H.

distribution on the rheological behaviour of

Ionic liquids for the production of man-made

cellulose/ionic liquid solutions during dry-jet

cellulosic fibres – opportunities and challenges.

wet spinning process. Proceedings of the 12th

Advances in Polymer Science, 2014, accepted.

European Workshop on Lignocellulosics and Pulp, Espoo, Finland, 27th-30th August 2012, pp.

Stépán, A. M., King, A. W. T., Kakko, T., Toriz,

134-137.

G., Kilpeläinen, I. and Gatenholm, P. Fast and highly efficient acetylation of xylans in ionic

Michud, A., Hummel, M. and Sixta, H. Influence

liquid systems. 2013, Cellulose, 20 2813-2824.

of molar mass distribution on the final properties of regenerated fibres from cellulose dissolved in

Conference proceedings

ionic liquid by dry-jet wet spinning. Proceedings of the 13th European Workshop on Lignocellulosics

Asaadi, S., Michud, A., Hummel, M. and Sixta,

and Pulp, Seville, Spain, 24th-27th June 2014.

H. High tenacity cellulosic fibres from novel ionic liquid-cellulose solution by dry-jet wet

Presentations:

spinning. Proceedings of the 13th European Workshop on Lignocellulosics and Pulp, Seville,

Hummel, M., Michud, A. and Sixta, H.

Spain, 24th-27th June 2014.

Structure formation of cellulosic material upon regeneration from ionic liquid solutions. (Oral

Hauru, L. K. J., Hummel, M. and Sixta, H. Fibre

presentation at the 243rd American Chemical

spinning from ionic liquid dope. Proceedings of

Society (ACS) meeting, March 2012, San Diego,

the 12th European Workshop on Lignocellulosics

USA).

and Pulp, Espoo, Finland, 27th-30th August 2012, pp. 272-275

FUBIO CELLULOSE PROGRAMME REPORT

Hummel, M., Michud, A., Hauru, L. K. J. and

Mänttäri, M., Keiski, R., Pihlajamäki, A., Nakari,

Sixta, H. Ionic liquids as powerful tool to

O., Valkama, H. and Turkki, A., Recovery of

exploit renewable biomass. (Oral presentation

Ionic Liquid by Hybrid Membrane Process (oral),

at the Technoport conference, April 2012,

FuBio Cellulose Seminar: Cellulose activation,

Trondheim, NO).

dissolution

and

fibre

regeneration,

Åbo

Akademi, 11th March 2013, Turku. Hummel, M., Michud, A. and Sixta, H. Solution state of cellulose in ionic liquids. (Oral

Sixta, H., Hummel, M., Michud, A., Hauru,

presentation at the 245th American Chemical

L. K. J., Roselli, A., King, A., Kilpeläinen,

Society (ACS) meeting, March 2013, New

I., Froschauer, C. and Schottenberger, H.

Orleans, USA).

Progress in Processing Lignocellulose with Ionic Liquids. (Oral presentation at The 3rd

Hummel, M., Michud, A., Asaadi, S., Tanttu, M.

International Cellulose Conference, October

and Sixta, H. High tenacity cellulosic fibres via

2012, Sapporo, Japan).

ionic liquid processing. (Oral presentation at the FuBio open seminar day, August 2013, Helsinki,

Sixta, H. Progress in processing lignocellulose

Finland).

with ionic liquids. Invited lecture at the University of Leipzig, Institute of Chemical

Hummel, M., Michud, A., Tanttu, M., Asaadi,

Technology, July 2013, Leipzig, Germany.

S., Ma, Y., Hauru, L. K. J., Hartikainen, E. and Sixta, H. Rheological aspects of ionic liquid

Sixta, H. Progress in processing lignocellulose

based fibre spinning. (Oral presentation for

with ionic liquids. (Oral presentation at the

the Finnish section of the Nordic Rheological

FuBio JR2 WP2 summer seminar, August 2013,

Society, March 2014, Espoo, Finland).

Helsinki, Finland).

Hummel, M., Michud, A., Roselli, A., Tanttu, M.,

Sixta, H., Hummel, M., Roselli, A., Asaadi,

Asaadi, S., Ma, Y., Hauru, L. K. J., Hartikainen,

S., Hauru, L. and Tanttu, M. Processing

E. and Sixta, H. Ioncell: From pulp to high-

lignocellulosic materials in ionic liquids. (Oral

performance fibres via ionic liquids. (Oral

presentation at the 3rd EPNOE International

presentation at the “Journée Scientifique des

Polysaccharide Conference, Nice, France, 21th-

GDRs LIPs et Biomatpro: Liquides ioniques et

24th October 2013).

polymères biosourcés“, April 2014, SophiaAntipolis, France).

Posters:

Michud, A., Hummel, M. and Sixta, H. Dry-

Hummel, M., Michud, A. and Sixta, H.

jet wet spinning of cellulose/ionic liquid (IL)

Extensional rheology of cellulose-ionic liquid

solutions. (Oral presentation at the 245th

solutions. Extended abstract and poster at the

American Chemical Society (ACS) meeting,

Nordic Rheology Conference, 6th-8th June 2011,

March 2013, New Orleans, USA).

Helsinki, Finland.

Michud, A., Hummel, M., Tanttu, M., Ma, Y., Asaadi, S. and Sixta, H. IONCELL-F Ionic Liquid based Fibre Spinning. (Oral presentation at the FuBio seminar, April 2014, Espoo, Finland).

FUBIO CELLULOSE PROGRAMME REPORT

Hummel, M., Michud, A., Hauru, L. K. J. and

Valkama, H., Niemistö, J. and Keiski, R. L.

Sixta, H. Applicability of various ionic liquids

“Pervaporation in ionic liquid’s recovery: Effect

in dry-jet wet spinning of cellulose solutions

of 1-Ethyl-3-methylimidazolium acetate on

(poster presentation at the 5th International

permeability properties of hydrophilic polymeric

conference

membranes”

Ionic

Liquids,

April

2013,

Vilamoura, Portugal).

(poster

presentation

the

FuBio Cellulose Programme Internal Seminar 12.6.2012, at the FuBio Programme Seminar

Michud, A., Hauru, L. K. J., Hummel M. and

1.10.2012 and at the XXIX EMS Summer School

Sixta H. Dry-jet wet spinning of cellulose-

on Membranes in Nancy, France, 11.7.2012; the

ionic liquid solutions (poster presentation at

abstract was also published in the abstract

the FuBio Cellulose seminar, June 2012, Espoo,

book of the XXIX EMS Summer School 2012).

Finland).

Theses: Michud, A., Parviainen, A., Hauru, L. K. J., Mutikainen, I., Kilpeläinen, I., Sixta, H.,

Benoît

Hummel, M. and King A. W. T. Tailored ionic

molecular weight distribution of cellulose on the

liquids for dry jet wet spinning of cellulose

rheological properties of cellulose-ionic liquid

solutions (poster presentation at the FuBio

solutions (Master’s thesis, 2012, Aalto Univeristy)

Cellulose

seminar,

August

2013,

Arnoul-Jarriault.

Influence

the

Helsinki,

Finland).

Hartikainen, Eeva. Solution state of cellulose in ionic liquids – A rheological study (Master’s

Michud, A. and Rissanen, M. From cellulose

thesis, 2013, Aalto University).

to textile fiber and a ready products (poster presentation at the SHOK summit seminar, May

Saastamoinen,

2014, Helsinki, Finland).

solute’s molecular weight distribution on the

Jouni.

Influence

the

spinnability of cellulose-ionic liquid solutions Nakari, O., Pihlajamäki, A. and Mänttäri, M.

(Master’s thesis, 2011, Aalto University)

Membranes for Recovery of Water-Ionic Liquid Solutions (poster), Fubio Cellulose internal

Selg, Christoph. New amidinium, imidazolium

seminar, 12th June 2012, Innopoli 1, Otaniemi,

and phosphonium ionic liquids for cellulose

Espoo.

dissolution and modification, (Master’s thesis, 2012, University of Helsinki)

Nakari, O., Pihlajamäki, A. and Mänttäri, M. Membranes for Recovery of Water-Ionic Liquid Solutions (poster), Fubio Cellulose and JR2 joint seminar, 1st October 2012, Innopoli 2, Otaniemi, Espoo. Tanttu, M., Michud, A., Asaadi, S., Ma, Y., Hummel, M. and Sixta, H. Textile application of cellulosic fibres from ionic liquid solution (poster presentation at the FuBio Cellulose Textile Company Workshop 31st October 2013, Espoo, Finland).

FUBIO CELLULOSE PROGRAMME REPORT

WATER-BASED DISSOLUTION AND REGENERATION PROCESSES C O N TA C T P E R S O N Marja Rissanen, marja.rissanen@tut.fi

PA R T N E R S Aalto University Lappeenranta University of Technology Mets채 Fibre Suominen Stora Enso Tampere University of Technology University of Helsinki University of Oulu UPM-Kymmene VTT Technical Research Centre of Finland

FUBIO CELLULOSE PROGRAMME REPORT

ABSTRACT The objective was to develop novel, sustainable water-based dissolution and regeneration processes for the production of a cellulosic staple fibre, and to demonstrate the regenerated fibres in textile and nonwoven structures. The chosen water-based process was the Biocelsol process. The dissolution factors involved in the Biocelsol process were studied to generate new knowledge to support the development of novel up-scalable pre-treatment and dissolution processes. The studies showed that both mechanical and enzymatic treatments are needed in order to obtain a spinnable dope. The mechanical treatment opened up the pulp fibre matrix to enzymes, while the enzymatic treatment reduced the molecular mass of the cellulose for dissolution in sodium zincate. The novel combined mechanical shredding and enzyme pre-treatment developed decreased the treatment time and enzyme dosage significantly. Based on the pre-treatment studies, it is expected that the dissolution process can be up-scaled to the industrial scale. The regeneration studies focused on trials of spin dope and spin bath additives for controlling the regeneration process. The maximum tenacity of the novel Biocelsol fibres (19 cN/tex) was achieved by using both spin dope and spin bath additives. This value was slightly lower compared to commercial viscose (22 cN/tex), but further optimization of the spin bath could increase the tenacity value. Enzyme recycling and removal of oligosaccharides from the pre-treatment filtrates as well as separation of acid and salts from the spin bath were demonstrated by nanofiltration. Two demonstration products, i.e. spunlaced non-woven sheets and a knitted hat, were manufactured from Domsjรถ softwood dissolving pulp. The processing properties of novel Biocelsol fibres were comparable to commercial viscose fibres. The novel chemical pre- and post-modification methods were demonstrated to achieve improved solubility and/or water absorption of regenerated fibres. The fibres regenerated from the premodified (butylated) pulp had slightly lower tenacity (15 cN/tex) compared to fibres from unmodified pulp. Water absorption, measured in terms of swelling coefficient, was 300% for the butylated fibres, which was significantly higher than both the unmodified Biocelsol fibres (170%) and commercial viscose fibres (100%). Post-modification of the regenerated fibres further improved the swelling coefficient to 500-1200%. In addition, the cellulose and hemicellulose molecular weight distribution was modelled as a function of process conditions in order to optimize conventional viscose fibre production.

Keywords: Biocelsol, modification of cellulose, nanofiltration, pre-treatment of cellulose, spunlaced nonwovens, modelling of viscose process

FUBIO CELLULOSE PROGRAMME REPORT

1. Work background Global annual consumption of textile fibres

The viscose process also consumes large

reached 90 million tonnes in 2012 and is

amounts of water and chemicals, of which CS2

increasing continually along with population

is extremely volatile and highly toxic. One of

growth and rising living standards. Cellulose-

the most promising sustainable water-based

based textile fibres (natural and man-made)

processes for the manufacture of MMCF is

have a comfortable texture and high moisture

the Biocelsol process (WO 2009/135875 A1)

absorption and are thus used mainly in apparel

developed at Tampere University of Technology.

and home textiles. Cotton is the main natural

In this process, chemical pulp is pre-treated

cellulose textile fibre, with an annual production

mechanically and enzymatically and then

yield of between 20â&#x20AC;&#x201C;27 million tonnes. The total

dissolved directly in sodium zincate (NaOH/

global area dedicated to cotton cultivation has

ZnO) solution using a freezing/thawing cycle.

barely changed for 90 years, yet yields have

The solution is then regenerated into fibres

tripled during this period. This has been achieved

using the wet spinning method. The benefits

through intensive consumption of irrigation

of the Biocelsol process are the lack of CS2 in

water, chemical pesticides, insecticides, and

the process and the possibility to use existing

fertilizers, and at no small ecological cost. Man-

viscose fibre plants for the manufacture of

made cellulosic fibres (MMCF), such as viscose,

regenerated fibres.

modal, cupro, lyocell, acetate, and triacetate, are made from cellulose dissolving pulp. MMCF

In order to further develop the Biocelsol

production stood at about 5 million tonnes in

process, deep understanding of the starting

2012, the majority of which was viscose fibre.

material structure and cellulose modification

Man-made cellulosic staple fibre production

and dissolution were needed. Development

has increased markedly during the past 10

and up-scaling of the pre-treatment processes

years at an average annual growth rate of 7.5%,

were also essential in order to decrease

compared to 3.2% for synthetic staple fibres.

the energy demand and to minimize water

Total textile fibre production has increased

consumption. The coagulation conditions were

5.4% during the same period.

adjusted to enhance fibre properties such as tenacity. Modification tools needed to be

The viscose process was invented as early as

developed in order to modify key regenerated

1892. In the process, dissolving pulp is first

fibre properties, such as water absorption and

treated with caustic soda, then with carbon

holding capacity for nonwoven applications.

disulphide (CS2), and dissolved in diluted caustic soda. The cellulose solution is then spun using the wet spinning method. The process is relatively

2. Objectives

lengthy and cellulose undergoes degradation

reactions during the treatment process. The final

The main objectives were to develop novel,

fibre quality is strongly dependent on the degree

sustainable

of polymerization (DP) of cellulose, the degree of

regeneration processes for the production of

substitution and the by-products present in the

cellulosic staple fibres, and to demonstrate

viscose solution. Models developed in the FuBio

the regenerated fibres in textile and nonwoven

Cellulose programme for different viscose steps

structures. Examination of dissolution factors

can be used for optimization of product quality

involved in the aqueous process aimed to

or for determining optimal process conditions

generate basic understanding of the dissolution

for specific product grades.

process used in the development of pre-

water-based

dissolution

and

FUBIO CELLULOSE PROGRAMME REPORT

treatment processes. The modifications, both

differently treated pulp was studied by means

pre- and post-modifications, aimed to improve

of solute exclusion, thermoporosimetry, and

cellulose dissolution and regeneration as well

different NMR methods. Crystal structures

as the properties of regenerated fibres, such

were evaluated by 13C CPMAS NMR and wide-

as increased water uptake. The cellulose and

angle X-ray scattering (WAXS) measurements.

hemicellulose molecular weight distribution

The nanoscale structure was examined with

modelling as a function of process conditions

small-angle X-ray scattering (SAXS). X-ray

was aimed at optimizing conventional viscose

microtomography

fibre production.

structural changes at the micrometre scale.

3. Research approach

was

used

observe

A novel pulp pre-treatment was developed to improve alkaline solubility without extensive reduction in chain length, and to reduce energy

The overall approach was to manufacture textile

and

water

consumption.

The

state-of-art

products and nonwovens from wood via the

Biocelsol treatment was used as a starting point.

production of chemical pulp, pulp dissolution

Several up-scalable mechanical treatments and

and regeneration using the novel Biocelsol

enzyme preparations and their combinations

method, and subsequent production of textiles

were screened and the applicability of the novel

and nonwovens, as summarized in Figure 1.

treatments was evaluated by means of solubility

The chemical pulp used was DomsjĂś softwood

tests. The solutions were characterized by

sulphite pulp (spruce-pine, viscosity 520 ml/g).

optical microscope and by measuring ball drop viscosity, the quantity of dissolved and

The dissolution factors were studied to support

undissolved content, and total cellulose content.

the development of up-scalable pre-treatment

The dissolution process during the freezing/

and dissolution processes for use in the novel

thawing cycle was examined using an optical

Biocelsol process. The treatment time of

microscope equipped with a cooling stage.

shredding and enzymatic hydrolysis as well as the enzyme concentration were varied to

Spinning trials ranging from small scale (5 kg

evaluate the structural changes in the cellulose

spinning dope) to large scale (60 kg spinning

pulp fibre. The pore structure of untreated and

dope) were carried out. Factors affecting

Figure 1. The production chain â&#x20AC;&#x201C; from wood to textiles.

FUBIO CELLULOSE PROGRAMME REPORT

filterability and degassing of the solution

Finally, a textile demonstration product was

were studied. The effect of drawing and

manufactured from the novel Biocelsol fibres.

other spinning parameters were evaluated. In addition, the effect of spin dope additives

In order to develop physico-chemical models

and the content of the spin bath on the

for the different steps in the viscose process,

spinning process and on the fibre properties

detailed information about related reaction

were studied. The linear density, mechanical

chemistry, side reactions and component

properties,

properties

swelling

coefficient,

and

fibre

was

collected.

Modelling

morphology were characterized from the

xanthation, ripening, and dissolution was

regenerated fibres.

carried out. A population balance based method was used for prediction of the molecular weight

In order to obtain an efficient process system,

distribution of cellulose during alkali cellulose

the purification and circulation of pre-treatment

ageing. A high-order numerical method capable

process water and the spin bath was evaluated.

of extremely accurate prediction of the integral

Purification of the enzymatic pre-treatment

properties of the distribution was applied.

filtrate from sugars, salts and dissolved

The method was also capable of predicting

oligosaccharides and separation of acids and

the actual distribution shape even in complex

salts from the spin bath were studied by means

states,

of nanofiltration tests.

Several scission rate models were proposed

such

multimodal

distributions.

and evaluated against the experimental data. Chemical pre-modifications of cellulose with different substituents were studied to improve the solubility of cellulose. Additionally, the

4. Results

pre-modification formed tags for a postmodification step (grafting, crosslinking, etc.). The spinning properties of pre-modified pulps

4.1 Development of a novel water-based cellulose dissolution process

were evaluated. TEMPO oxidation as preand post-modification was used to improve

The

solubility and to create charged groups for

sustainable and techno-economically feasible

objective

was

develop

novel,

better water absorption. In addition, post-

water-based dissolution process for wood pulp

modification routes, such as grafting and

cellulose. Dissolution factors were studied

click-chemistry, were used to improve the

to generate new knowledge to support the

water absorption properties or to functionalize

development of pre-treatment and dissolution

regenerated fibres.

processes. The focus was on understanding the changes in the cellulose fine structure occurring

The Biocelsol fibres were demonstrated in

during mechanical treatment (shredding) and

spunlaced nonwovens and a textile product.

enzymatic hydrolysis, and understanding the

Non-woven sheets were manufactured in lab-

effect of process chemistry, including additives

scale pilots from the state-of-art, novel and

and

modified (with acrylic acid) Biocelsol fibres. The

The Biocelsol process was used as a model

fibres were carded and the webs hydroentangled

dissolution system.

physical

parameters,

dissolution.

with high-pressure water jets. The processing

properties of the fibres and the water absorption

Dissolution factors

and tensile properties of non-woven sheets

The

were compared to commercial viscose fibres.

mechanical treatment opened the pulp fibre

experimental

data

showed

that

the

FUBIO CELLULOSE PROGRAMME REPORT

matrix not linearly but stepwise according to

ml/g to 360 ml/g in 30 minutes). The enzymatic

the treatment time. The cellulose structure

treatment was found to first rapidly result in

broke down or collapsed after a certain amount

cellulose chain cleavage, leading to decreased

of stress (mechanical shredding). The molar

viscosity. Prolonging the treatment time did

mass and viscosity results showed that a

not cause further reduction in chain length or

longer mechanical treatment time increased

viscosity but merely increased the amount of

the susceptibility of the fibres to subsequent

carbohydrates dissolved from the pulp. Based

enzymatic hydrolysis. The solute exclusion

on this result the amount of accessible sites for

method, used for determination of micro and

enzyme seems to be the limiting factor for the

macro pores in the fibre wall, showed that the

degree of enzymatic modification. No effect

mechanical treatment has a dominant effect on

of enzymatic treatment on the crystal size or

fibre swelling. The results were confirmed with

crystallinity of cellulose was observed by the

X-ray diffraction, NMR-cryoporosimetry and

solid-state NMR spectroscopy studies.

thermoporosimetry analysis. The SAXS results showed a slight loosening of the microfibril

The molar mass and pore size of pre-treated

bundles during the mechanical treatment.

pulp were found to be the limiting factors for

According to the WAXS and solid-state NMR

dissolution in the Biocelsol system. Analyses

spectroscopy results, the duration of mechanical

of the soluble and insoluble fractions showed

treatment did not affect the cellulose crystal

that the soluble fractions had lower molar

size nor the crystallinity of the samples. The

mass compared to the original pulp, whereas

crystallinity of differently pre-treated cellulose

the insoluble fraction had the higher molar

samples varied between 60-62%, whereas

mass fraction. The solute exclusion method

the crystallinity of untreated pulp was 54%.

and

The slightly lower crystallinity of untreated

that the mechanical treatment opened the

pulp might be due to the dissolution of some

structure up for enzymatic treatment, and a

amorphous material during soaking of the pulp

higher enzyme dosage resulted in larger pores

sheets before mechanical shredding.

in the pulp. The larger pores most likely allowed

thermoporosimetry

studies

showed

NaOH/ZnO to penetrate more efficiently into of

the pulp fibre, thus increasing the quality

mechanically treated pulp was to decrease the

of the solution. The relationships between

pulp weight average molecular mass (Mw) and

molar mass and viscosity and solubility in the

thus viscosity to a targeted level (e.g. from 520

Biocelsol systems are shown in Figure 2.

2500 2000 1500 1000 500 0

enzymatic

treatment

3500

120

3000

100

2500

97%

2000 1500

E1, 1mg/g

1000

E1, 0.25 mg/g E1, 0.25 mg/g 98% 500 88% 88% 98% 0 99% 99% 100000 200000 300000 400000 500000 100000 0 200000 300000 400000 500000

Solubility, %

3000

aim

Solubility, %

3500

Drop ball viscosity, s/20cm

The

80 60 40

80 M5 60 40

M2.5

M2.5 M5 M2.5 M0.5 M0.5 M1 M1 M5 M0.5 M2.5 M1

M0 M0.5 M1 M0

Mw, g/mol Mw, g/mol

M0 E1, 1mg/g

E0 E1, 1mg/g

E1, 0.25 mg/g E1, 0.25 mg/g

20 0

0 0 200000 100000 200000 300000 400000 500000 100000 300000 400000 500000

Mw, g/mol Mw, g/mol

Figure . Ew ffect f a) Mw on viscosity b) on solubiltiy Figure 2. Effect of Figure a) 2M on voiscosity b) on solution solubiltiy 2. Effect of molecular mass (Mw) on viscosity of cellulose (alkaline solubility of the samples

shown as %) (left) and on solubility (right). MX = time of mechanical shredding before enzyme treatment. Solub. % Solub. % for treatment. E01mg/g E1, E1, 1mg/g Mw E0Mw E1, 0.25 mg/gE1, 0.25 mg/g

Fb-‐visc. Fb-‐visc. E0, E1=commercial enzyme preparations used Mw E1, 1mg/g Mw E1, 1mg/g E1, 0.25 mg/gE1, 0.25 mg/g 405000 405000 368431 368431 295540 2908 295540 2908 263724 484 263724 484 230572 172 230572 172 212931 60 212931 60 404518.5 404518.5 301632 301632 307629.5 307629.5 214167 214167 FUBIO CELLULOSE PROGRAMME REPORT 191074 436 191074 436

405000 368431 295540 263724 230572 212931 404518.5 301632 307629.5 214167 191074

405000 41 41 368431 66 66 29554097.347161 97.347161 263724 98.87594 98.87594 23057299.378971 99.378971 212931 100 100 404518.5 46.300552 301632 49.943442 307629.5 58.742995 214167 55.64942 191074 88.260604

46.300552 49.943442 58.742995 55.64942 88.260604

The Biocelsol system requires a freezing/thawing

Two novel mechanical treatment devices and

cycle during dissolution. The mechanically and

two commercial enzyme preparations were

enzymatically pre-treated pulp fibres dissolved

found to have the most potential for the novel

through

ballooning.

pre-treatments. The solubility of the novel pre-

Conversely, the untreated and only mechanically

treated pulp was better compared to the solubility

treated samples dissolved mainly by swelling

of state-of-art treated pulp, as shown in Figure

and ballooning. Dissolution of the pre-treated

4. In addition, the novel pre-treatment enabled a

samples started when the temperature reached

significant decrease in enzyme dosage (0.25 vs. 1

0 째C. The untreated pulp started to dissolve at

mg/g), higher treatment capacity (200 g/20 min

a much lower temperature (-15 째C) compared

vs. 70 g/h.), and higher cellulose concentration in

to the mechanically and enzymatically treated

the solution (7wt% vs. 5.5wt%).

fragmentation

without

samples, as shown in Figure 3. The most important process parameters in the freezing/

The pre-treatment consistency had no clear

thawing cycle were the cooling rate, the lowest

effect on dissolution in NaOH/ZnO. However,

temperature of sample, and the duration of the

if mixing at high consistency could be carried

sample at low temperature.

out at higher speed, the resulting fibre-fibre interactions might achieve better results. The

Pre-treatment process development

best pre-treatment process developed was up-

Several up-scalable, cost-effective mechanical

scaled to 200 g/20 min and the sodium zincate

methods and commercial enzyme preparations

dissolution process was up-scaled to 60 kg

and their combinations were screened. For

dope. It is now expected that both processes

example,

can further be up-scaled to the industrial scale.

horizontal

high-intensity

agitated

homogenizator,

laboratory

pearl

mill,

planetary ball mill, and ultrasound treatment

Preliminary

were trialled for mechanical treatment, but

showed that some of the enzyme can be

studies

enzyme

recycling

none proved sufficiently effective.

recycled. Two-stage filtration (NF270 and NF90

Figure 3. Microscopy images during dissolution of differently pre-treated pulp in NaOH/ZnO a) untreated, b) mechanically shredded (5h) and c) mechanically and enzyme treated. Upper row = 0 째C, lower row = -20 째C.

FUBIO CELLULOSE PROGRAMME REPORT

80 60 40 20 0

140

120

100

Novel mechanical tr. Novel mechanical tr. SCAN <220 SCAN <220 Novel mechanical tr. Novel mechanical tr. SCAN 250-‐260 SCAN 250-‐260 State-‐of-‐art mechanical State-‐of-‐art echanical tr. Sm CAN 240-‐250 tr. SCAN 240-‐250

80 60 40 20 0

4.5 5 5 5.5

4.5

5.5 6 6 6.5

6.5 7 7 7.5

100

7.5

Cellulose concentra)on, % Cellulose concentra)on, %

Figure 4 Drop ball time a) Figure 4 Drop ball time a)

80 60 40 20

140 Drop ball )me, s/20cm

100

140

Drop ball )me, s/20cm

120

Drop ball )me, s/20cm

140

1mg/g E1, 6.16% 1mg/g E1, 6.16% 1x with 0.25 mg/g E1, 1x with 0.25 mg/g E1, 6.26% 6.26% 1x + (1x with 0.25 mg/g E1) 1x + (1x with 0.25 mg/g E1) 6.13% 6.13%

120 100 80 60 40 20

Novel mechanical tr. Novel mechanical tr.

0 100 150

0 100

150 200

200 250

State-‐of-‐art mechanical 300 State-‐of-‐art mechanical tr. tr.

250 300

SCAN viscosity, ml/g SCAN viscosity, ml/g

Figure 4. Drop ball time of the alkaline solution b)as a function of cellulose concentration of the solution (left), and SCAN of the-‐> spulp (right). Kuviin muutettu extruder viscosity -‐> novel ja Baker Perkins tate-‐of-‐art

Kuviin muutettu extruder -‐> novel ja Baker Perkins -‐> state-‐of-‐art

alfa, %

matalin matalin alfa, % kuula, s/20cm kuula, s/20cm

Liuokset

Liuokset alfa, %

matalin matalin alfa, % kuula, s/20cm kuula, s/20cm

Novel mechanical State-‐of-‐art tr. SCAN Novel mechanical <220 mechanical tr. SCAN tr. water 2 SCAN 40-‐250 250-‐260 membranes) the process from the Novel mechanical State-‐of-‐art tr. of SCAN Novel mechanical <220 mechanical tr. SCAN tr. 2 SCAN 40-‐250 250-‐260

SCAN, ml/g Koodi Novel mechanical State-‐of-‐art tr. novel mechanical tr.pre(prepared developed SCAN, ml/g Koodi using the Novel mechanical State-‐of-‐art tr. mechanical tr.

6.05 32 enzymatic 6.05 32 treatment significantly improved the

200 process) 6.05 textile 32 product. TUT254b treatment 200 6.05 in a 32 TUT254b FBC-‐

6.13 56 removal of dissolved 6.13 56 organics and salts. The 6.3 44 treated water had 44 significantly higher purity, 6.3 6.49 56 and NF90 membrane was 6.49 fouling of the tighter 56 6.8

7 6.15 6.2624 6.17 6.1448 6.5932 6.9460 116 6.16 5.7 5.46

112

remarkably reduced.72 The total organic content 6.8

FBC-‐

250

FBC-‐ 250 TUT268 FBC-‐ 170 TUT269 FBC-‐ 260 TUT270 FBC-‐ 220 TUT271 FBC-‐ 250 TUT133

TUT268 6.13 FBC-‐

6.13 56

24 TUT269 Regeneration of 6.15 novel6.15Biocelsol dopes 24 170 FBC-‐

6.26 88 TUT270 The260regeneration of cellulose 6.26 or coagulation 88 FBC-‐

6.17 48 TUT271 should proceed through 6.17 48 the gelling process. 220 FBC-‐

of 7the process water 112 was about 8.2 ppm after 24

6.16 128 TUT133 If the coagulation process 6.16 128is too fast, the 250

the two-stage (unfiltered process 88 48 NF process

cellulose solidifies too quickly preventing the

6.15 6.26 6.17 6.14 6.59 6.94 6.16 5.7 5.46

32 water over 1400 ppm). The conductivity was 60

high draw ratios of as-spun fibres and resulting

6.2 μS/cm (at 25 °C) 128 (unfiltered process water

in low fibre tenacity. Spin dope and spin bath

52 μS/cm).

additives were tested for their effect on slowing

116

128 108 40

108 40

coagulation and increasing the draw ratio.

4.2 Regeneration of cellulosic fibres The combined effect of spin dope and spin bath

n dope The objective was to develop a commercially Raw cellulose staple fibre spinning process d bath viable ditives Filtration material for a water-based cellulose solution, and to

demonstrate the advanced Biocelsol fibres

additives proved most effective for increasing fibre tenacity, as shown in Figure 5. A clear effect on fibre properties was also obtained when the degree of filtration was altered.

Tenacity, cN/tex

18.80

Spin dope addifve

10 Spin bath addifve

5 0

17.40

Reference

20 22 24 ElongaBon, %

Spin dope and bath addifves Filtrafon

Figure 5. Tenacity and elongation of fibres at rupture.

11.90 12.00 14.20 15.60 14.90 15.40

1.46 FUBIO 1.45 CELLULOSE PROGRAMME REPORT 1.39 1.33

A dope additive (alkylpolyamine polyoxyethylene

The design of the textile product was produced

glycol) was needed to remove the air bubbles from

by Studio Tint Ltd, Finland, and included the

the filtered high-viscosity solutions. In addition,

colour and pattern of the knitted textile as well

the dope additive enabled storage of the dope at

as the model of a hat with an embroidered

ambient temperature for several days.

Biocelsol brand mark. The industrial-scale flatbed knitting and sewing was done by Nevil

The fibre tenacity of the advanced Biocelsol

Ltd, Finland. The knitted structure was dyed

fibres was 19 cN/tex (state-of-art Biocelsol fibre

at TUT according to a dyeing recipe obtained

13 cN/tex). Fibre spinning was scaled-up from

from Nanso Ltd, Finland. The Biocelsol mark

50 g to 3 kg of fibre.

was embroidered by Brodeca Ltd, Finland. The demonstration textile product, a Biocelsol hat,

Textile demonstration

is shown in Figure 6.

The applicability of the advanced Biocelsol fibres for textile products was demonstrated.

Spin bath recycling was studied using the

The fibres were regenerated, spin-finished, and

two-stage nanofiltration (NF) process. In the

opened at Tampere University of Technology

first stage, dissolved oligosaccharides were

(TUT). The carding, ring spinning, and plying

removed with the open NF membrane (NP030,

processes were performed at the Swedish

NP010 and NTR-7450). The oligosaccharide

School of Textiles (University of Bor책s, Sweden).

retentions were relatively low (<50%). In the

The carding and yarn spinning properties of the

second stage, salts and acids were separated

advanced Biocelsol fibres were good due to the

with the tight NF membrane (Desal-5 DK and

suitable crimping of the fibres. The crimps are

MPS-36), and only slight separation between

formed during the regeneration stage and no

acid and salts was achieved. Other membranes

further fibre crimping or texturization is needed.

should therefore be tested to achieve efficient separation of spin bath compounds.

Figure 6. Biocelsol knitted hat.

FUBIO CELLULOSE PROGRAMME REPORT

4.3 Modifications

The modification routes of cellulose (both pulp and regenerated fibres) are presented in Figure 7.

Chemical modifications were divided into pre-

Routes i, ii, and iv were used for pre-modification

modifications, i.e. modification of the pulp

and routes ii, iii, iv, and v for post-modification.

prior to dissolution, and post-modifications,

The chemical modification routes were:

i.e. modification of the regenerated fibres. Some of the modification routes used are

i. Functionalization of cellulose with butyl

suitable for both pre- and post-modification.

groups containing reactive double

The objectives of pre-modification were to

bonds. These can be further cross-

improve cellulose dissolution in NaOH/ZnO and/

linked and grafted with hydrophilic

or improve the water absorption properties of

monomers such as acrylic acid (AA) and/or

fibres regenerated from the modified pulp. The

2-acrylaminomethylpropane sulfonic acid

objectives of post-modification were to improve the water absorption of regenerated fibre and

(AMPS). ii. Functionalization of cellulose with allyl

to functionalize the obtained fibres. High water

groups, followed by grafting or cross-linking

absorption properties are required for nonwoven

as in route (i).

products such as wipes, diapers, incontinence products, and feminine hygiene products.

iii. Grafting of cellulose with hydrophilic monomers as in route (i).

Figure 7. Chemical modification routes: functionalization with (i) butyl or (ii) allyl groups followed by (iii) grafting, (iv) TEMPO oxidation, and (v) click chemistry.

FUBIO CELLULOSE PROGRAMME REPORT

iv. Oxidization of cellulose fibres, e.g. TEMPO

dissolved well in NaOH/ZnO. Due to the high

oxidization. Cellulose is oxidized to cellulose

surface activity of the pulp, extreme quantities

derivatives containing carboxylic acid

of air bubbles were formed in the alkaline

groups, which can be further modified

solutions, as shown in Figure 8.

for other functionalities or used as crosslinkable functionalities (pre- and post-

The spin dope made from the butylated pulp

modification).

regenerated easily into fibres. However, the

v. Click chemistry

spin dope made from the allylated pulp did not regenerated properly, and the allylated solution

Modification of pulp and its regeneration into

was thus mixed with unmodified solution in

fibres

ratios 1/4 and 1/10 prior to spinning.

For the dissolution and regeneration tests, 3-butoxy-2-hydroxypropyl (butylated, B in Figure

Tenacity and elongation of regenerated fibres

3-allyloxy-2-hydroxypropyl

from the modified pulps and reference pulp

(allylated, A in Figure 7) cellulose samples

were at the same level. However, the swelling

were prepared. The allylated sample with

coefficient of the regenerated fibres from

degree of substitution, DSA, 0.09 had higher

butylated pulp was huge compared to that of

solubility (7wt%) in NaOH/ZnO compared to the

the other fibres, as shown in Figure 9. Water

unmodified pulp (6wt%). Butylated pulp also

absorption values are measured as the swelling

cellulose

and

Figure 8. Effect of mixing on the formation of air bubbles in alkaline solution from butylated pulp, a) mixed with a laboratory mixer and b) mixed by hand.

Figure 9. Water absorption capacity of the regenerated fibres as measured by swelling coefficient value.

FUBIO CELLULOSE PROGRAMME REPORT

coefficient, which indicates the amount of

chains. This route was based on etherification

water that the sample is able to hold under

of cellulose fibres with substituents containing

centrifugation. For example, fibres regenerated

allyl functionalities, as shown in Figure 7

from butylated pulp can absorb three times

(ii). Fibres having reactive double bonds can

their own weight of water, whereas commercial

be grafted in very mild aqueous conditions.

viscose absorbs only its own weight of water.

Swelling ratio was improved up to 1200% (Table 1), meaning that 1 g of modified regenerated

TEMPO oxidation increased the carboxyl content

fibre can absorb 12 g of water. Water absorption

of the pulp, and this could be further increased

properties were highest when the samples

with NaClO2 treatment. The solubility of TEMPO-

were converted into neutralized sodium salt

oxidized pulp fibres in NaOH/ZnO was higher

form. The tenacities of the PAA grafted samples

compared to unmodified pulp. Unfortunately,

were slightly lower compared to the unmodified

the solutions made from TEMPO-oxidized pulp

fibres (8 cN/tex vs. 11 cN/tex) as the grafted PAA

were not suitable for fibre regeneration.

increased the fibre weight (linear density in tex is defined as mass in grams per 1000 metres of fibre).

Modification of regenerated fibres

The post-modifications reported in this chapter can be performed on all types of regenerated

Modification with some anhydrides, such as

cellulose

advanced

maleic anhydrides, gives the fibres reactive

Biocelsol fibres and commercial viscose fibres

double bonds, and at the same time enables

were used for the trials.

the hydrophilic-hydrophobic balance of the

fibre.

Reference

and

fibres to be adjusted. The advantage of For

non-woven

trials,

advanced

Biocelsol

etherification is that ether bonds are rather

fibres were first allylated and then grafted with

stabile in acidic and especially in strong alkaline

different amounts of acrylic acid to obtain post-

conditions. Ester bonds, as in the case of maleic

modified fibres containing poly(acrylic acid) (PAA)

acid derivatives, can be hydrolysed more easily

Table 1. Mechanical properties and water absorption capacities of the post-modified fibres measured by swelling coefficient value. Water absorption capacity %

Tenacity cN/tex

Elongation %

Biocelsol fibre

140

10.9

Lenzing viscose

22.5

in acid form

170

8.4

in neutralized form

1170

7.6

560

8.7

in acid form

160

6.0

in neutralized form

240

8.1

Sample Reference samples

Biocelsol fibres grafted with 32% PAA Small-scale batch

Bench-scale batch for non-woven trials in neutralized form Biocelsol fibres modified with maleate

FUBIO CELLULOSE PROGRAMME REPORT

in alkaline conditions. Some fibres with maleate

of CMC onto cellulose was combined with click

substituents were prepared, but grafting of

chemistry

these fibres was not performed. The results are

preparing cross-linked Biocelsol fibres. First,

presented in Table 1.

an azide derivative and an alkyne derivative

(alkyne-azide

cycloaddition)

for

were adsorbed on the fibre surface. Next, the Two different advanced Biocelsol fibre samples

click reaction was executed to bring together

were

modification

the modified regenerated fibres via crosslinking

improved water absorption if the fibres were

TEMPO

reaction with the aim of improving the

washed

oxidative

mechanical properties of the fibres. However,

treatment showed detrimental effects on the

no improvement in mechanical properties was

mechanical properties of regenerated fibre, as

found to have resulted from the crosslinking.

oxidized.

Na+-form.

The

However,

shown in Figure 10.

4.4 Nonwovens from Biocelsol fibres A click reaction can be used for postmodification of regenerated fibres, as shown

The objective of the non-woven trials was to test

in Figure 7 (v), and for functionalization of

the processing properties of the Biocelsol fibres

regenerated fibres. The irreversible adsorption

developed in the FuBio Cellulose programme,

Water absorp+on capacity,%

300 250 200

REF

150

H+

100

Na+

50 0

Biocelsol

Viscose

Tenacity, cN/tex

25 Figure 10 Effect of Tempo 20

Biocelsol-‐REF

Biocelsol-‐Na+ Biocelsol-‐H+

SwC, % 5

REF H+ 0 Na+ 0

Biocelsol Viscose 176 107 131 102 5 287 10 210

Viscose-‐REF Viscose-‐Na+ 15

Viscose-‐H+

Elonga+on, % Figure 10. Effect of TEMPO oxidation on the water absorbency (a) and mechanical properties of regenerated cellulose fibres (b).

Elong, %

Biocelsol-‐REF Biocelsol-‐Na+ Biocelsol-‐H+

Tenacity, cN/tex 20,47 10,9 12,63 15,47

8,6

FUBIO CELLULOSE PROGRAMME REPORT 9,20

and to characterize the properties of the

for all blended samples. Wet-state thicknesses

obtained nonwoven sheets. The nonwoven

varied between 0.4â&#x20AC;&#x201C;0.5 mm for non-blended,

sheets

and between 0.6â&#x20AC;&#x201C;0.7 mm for blended samples.

were

manufactured

spunlacing

(carding and hydroentanglement). The water absorption properties are presented The processing properties of state-of-art

in Table 2. The absorption capacity (measured

Biocelsol and advanced Biocelsol fibres were

as swelling coefficient, Table 1) of the fibres

comparable to commercial viscose fibres in

does not translate directly into the absorption

carding and hydroentanglement carried out in

capacity of the nonwovens because a lot of the

pilot line for preparing spunlaced non-woven

absorption correlates to the void space in the

(Figure 11). Both 100% Biocelsol nonwoven

nonwoven structure. This can clearly be seen in

sheets and 50% Biocelsol: 50% polyester blend

the higher absorption of the 50% regenerated

nonwoven sheets were manufactured. The

cellulose: 50% polyester blends compared to

basis weights of the samples varied between

the nonwovens of 100% regenerated cellulose

43-50 g/m2. Dry-state thicknesses were 0.5

fibre. It is well known that the addition of

mm for all non-blended samples, and 0.7 mm

synthetic fibres to a viscose mix increases the dry and wet thickness of the nonwoven, which is reflected in absorption increase. The highest absorptive capacity was reached with the 50% chemically modified Biocelsol: 50% polyester blend. This was, however, only a 15% increase over the comparable commercial blend, which cannot be considered a major improvement. The mechanical properties of nonwoven sheets are presented in Figure 12. The tensile strength values of nonwovens made from Biocelsol fibre were lower compared to nonwovens made from commercial viscose. The dry tensile strength of non-wovens made from 50% modified Biocelsol: 50% polyester blend was relatively good, but

Figure 11. Pilot line for preparing spunlaced nonwovens.

dropped to very low levels when wet.

Table 2. Water absorption properties of non-woven samples Property

Basis weight

Water absorptive

Water absorbency

(g/m2)

capacity (g/g)

time (s)

100% Lenzing viscose

43.3

11.8

1.3

100% state-of-art Biocelsol

53.5

9.9

4.9

100% novel Biocelsol

49.5

10.9

1.5

50% viscose : 50% polyester

45.9

12.9

4.6

50% state-of-art Biocelsol : 50% polyester

50.6

12.1

2.4

Fibre blend

50% advanced Biocelsol : 50% polyester

49.8

13.0

1.9

50% chem.modified Biocelsol : 50% polyester

44.3

14.8

2.2

FUBIO CELLULOSE PROGRAMME REPORT

100 Force (N)

80 60 40 20 0

Tensile strength MD, Tensile strength CD, Tensile strength MD, Tensile strength CD, dry dry wet wet 100% viscose

100% state-‐of-‐art Biocelsol

100% novel Biocelsol

50% state-‐of-‐art Biocelsol : 50% PES

Elonga/on (max %)

50% novel Biocelsol : 50% PES

140 120 100 80 60 40 20 0

ElongaSon MD, dry ElongaSon CD, dry ElongaSon MD, wet ElongaSon CD, wet 100% viscose

100% state-‐of-‐art Biocelsol

100% novel Biocelsol

50% viscose : 50% PES

50% state-‐of-‐art Biocelsol : 50% PES 50% novel Biocelsol : 50% PES

Figure 12. Mechanical properties of non-wovens (MD = machine direction, CD = cross direction).

4.5 Modelling of hemicellulose and cellulose chain length distribution evolution as functions of process conditions in the viscose process

Normally, fresh xanthated cellulose solution has DS values of 0.5–0.7 after 80–120 minutes of xanthation and seldom exceeds DS 1. The simulation results give DS 0.5–0.65 for the same xanthation period.

Physico-chemical

models

were

developed

for the different steps involved in viscose

The evolution of molecular weight distribution

fibre production (xanthation, ripening and

(MWD) can be modelled by population balance

dissolution).

amount

models. Discretization of MWD into categories

of experimental data was available in the

representing a certain DP range considerably

literature for development of the model, the

reduced the computational time. A model for

model provided basic information in accordance

prediction of changes in MWD during alkali-

with the literature, such as the relative

cellulose aging was developed and different

concentration of different species, changes in

equations for polymer scission rate were

the degree of substitution of cellulose, change

tested. Promising results were obtained from

in reactor pressure, etc. As an example, the

the scission rate equation given below.

Although

limited

simulated change in degree of substitution

during xanthation is illustrated in Figure 13.

ScissionRate = k(1-exp[-((DP-1)/c)d].exp(-a.t)

The degree of substitution was defined as the

Values of ‘k’, ‘a’, ‘c’, and ‘d’ are constant and

number of xanthate groups present on one

their values were optimized. ‘DP’ is degree of

anhydro-glucose unit of the cellulose chain.

polymerization and ‘t’ is ageing period.

FUBIO CELLULOSE PROGRAMME REPORT

Degree of subs6tu6on 0,8

0,7

0,6

DS (number/AGU)

0,5

0,4

0,3

0,2

0,1

120

160

Time (min)

Figure 13. Degree of substitution from simulation (xanthation).

Comparisons

model

process steps For the model development,

results for different ageing periods are shown

experimental

and

experimental MWDs from the other steps should

in Figure 14. Continuous lines represent the

be available for optimizing the parameters in

experimental MWD, while dots represent the

the scission rate equations. The experimental

discretized categories from the model. As

method generally used for analysis of MWD

cellulose degradation takes place continuously

does not provide very accurate results for the

throughout the viscose process, a model similar

lower molecular weight range, which makes

to ageing could be implemented for the other

accurate MWD modelling more challenging. 2 hr

1 hr 1.2

1 hr

1.0 1.2

dw/d(log Mw) dw/d(log Mw)

dw/d(log dw/d(log Mw) Mw)

1.2

0.8 1.0 0.6 0.8 0.4 0.6 0.2 0.4 0.0 0.2

0.0

0.6 0.8 0.4 0.6 0.2 0.4

0.0

log Mw 3

0.8 1.0

0.0 0.2

2 hr

1.0 1.2

log Mw

dw/d(log Mw) dw/d(log Mw)

dw/d(log dw/d(log Mw) Mw)

4 hr

0.8 1.0 0.6 0.8 0.4 0.6 0.2 0.4

0.0

8 hr

1.0 1.2 0.8 1.0 0.6 0.8 0.4 0.6 0.2 0.4 0.0 0.2

0.0

log Mw 3

8 hr 1.2

1.0 1.2

0.0 0.2

log Mw

4 hr 1.2

log Mw

log Mw 3

log Mw

Figure 14. Comparison of experimental (lines) and model (dots) MWDs for different ageing periods.

FUBIO CELLULOSE PROGRAMME REPORT

Population balance based modelling has now

Replacement of the current viscose process

been implemented to predict the evolution

with the novel water-based dissolution and

of molecular weight distribution of cellulose

regeneration

during alkali cellulose ageing. These models

environmental impact of regenerated fibre

can be used for optimizing viscose process

manufacturing. Price competitiveness, however,

conditions for a certain end product quality.

remains a key challenge for the implementation

process

would

reduce

the

of Biocelsol fibre.

5. Exploitation plan and impact of the results

Process models of different viscose process steps could be used for optimizing process conditions and product quality. The information

The results obtained on the effects of enzymatic

obtained from these models could, in turn,

pre-treatment on molecular weight and fibre

be used in the evaluation of various process

surface pores can be utilized in planning pre-

alternatives during the development of new

treatments to activate cellulose for dissolution

processes. The modelling work thus supports

to advanced Biocelsol or other water-based

the development of more cost-efficient and

systems, as well as for chemical synthesis. The

environmentally

results regarding combined mechanical and

is not only beneficial for industry but also for

enzymatic pre-treatments indicate that there is

the environment and society. New process

a potential to decrease the enzyme dosage and

understanding gained through modelling could

mechanical energy usage and thus enhance the

also be used in teaching at university level.

friendly

processes,

which

economic feasibility of mechanical-enzymatic pre-treatment. It is also expected that both the pre-treatment and the dissolution process can

6. Networking

be up-scaled to the industrial level. Recycling of water, enzymes and chemicals in the Biocelsol

The research was carried out jointly by research

process by membrane separation requires

organizations, Finnish forest cluster companies,

further development.

and other companies. Table 3 presents the research partners and their roles.

The

results

advanced

Biocelsol

fibre

regeneration and demonstrations of spunlaced nonwovens and textile products are promising. The unmodified and modified Biocelsol fibres have higher water uptake values compared to commercial viscose fibres. Applications for Biocelsol-based fibres should reflect this special property. However, the mechanical properties of Biocelsol fibres need further development. Further modification and improvement of the mechanical properties could be achieved, for example, by utilizing the reactive allylic double bonds of modified and regenerated fibres in suitable post-crosslinking and post-grafting techniques.

FUBIO CELLULOSE PROGRAMME REPORT

Table 3. Partner organizations and their roles. Partner

Role

Aalto University

FPT: Characterization of pore structure (thermoporosimetry and solute

- Forest Products Technology (FPT)

exclusion techniques); post-modification of regenerated fibres (click-

- Biotechnology and Chemical

chemistry, TEMPO oxidation)

Technology (BCT)

BCT: Physico-chemical modelling of viscose process steps.

Lappeenranta University of

Filtration studies.

Technology - Separation Technology Metsä Fibre

Industrial tutor. Defining, steering and providing competence for the viscose modelling.

Suominen

Industrial tutor, manufacturing and characterization of spunlaced nonwovens.

Stora Enso

Industrial tutor. Giving industrial insight and steering of the work.

Tampere University of

Solubility trials, SCAN viscosity measurements of pulp and regenerated

Technology

fibre, preparation of spin dopes, fibre spinning trials, management of

-Materials Science

textile demonstration.

University of Helsinki

PC&XP: Characterization of fibre pore structure (NMR methods, X-ray

- Polymer Chemistry (PC)

studies)

- X-ray Physics (XP)

PC: Characterization of dissolution process.

University of Oulu

Experiments of mechanical treatments.

-Fibre and Particle Engineering UPM-Kymmene

Industrial tutor. Giving industrial insight and steering of the work.

VTT

Mechanical and enzymatic treatments, factors affecting cellulose dissolution, pre-treatment process development; pre- and post-modifications.

7. Publications and reports Publications: Pahimanolis, N., Salminen, A., Penttilä, P.,

Rissanen, M., Syrjälä, S., Vehviläinen, M.

Korhonen, J., Johansson, L., Ruokolainen, J.,

and Nousiainen, P. Solubility and solution

Serimaa, R. and Seppälä, J. Nanofibrillated

rheology of enzymatically treated pulp. Annual

cellulose/carboxymethyl cellulose composite

Transactions of the Nordic Rheology Society,

with improved wet strength. Cellulose 20(3),

Vol. 19, 303-306, 2011.

1459-1468, 2013. Grönqvist, S., Hakala, T. K., Kamppuri, T., Vehviläinen, M., Hänninen, T., Liitiä, T., Maloney, T. and Suurnäkki, A. Fibre porosity development mechanical

of and

dissolving enzymatic

pulp

during

processing.

Cellulose 2014. DOI 10.1007/s10570-014-0352-x.

FUBIO CELLULOSE PROGRAMME REPORT

Presentations:

Posters:

Grönqvist, S., Maloney, T., Kamppuri, T.,

Michud, A. and Rissanen, M. From Cellulose

Vehviläinen,

T.,

to textile fibre and a ready product. Poster

Hänninen, T., Suurnäkki, A. Activation of

presentation at SHOK Summit 2014, May 15,

cellulose. Oral presentation in FuBio seminar,

2014, Helsinki, Finland.

M.,

Hakala,

T.K.,

Liitiä,

August 25, 2013, Helsinki, Finland. Hänninen, T., Kamppuri, T., Vehviläinen, M., Kamppuri, T., Vehviläinen, M., Grönqvist, S.

Grönqvist, S., Hakala, T.K. Dissolution of

and Rissanen, M. Novel regenerated cellulose

TEMPO oxidized pulps in aqueous alkaline

fibres with high water absorption properties.

solvents.

Oral presentation in Ambience'14 & 10i3m

seminar, November 20, 2013, Espoo, Finland.

Poster

presentation

FIBIC

Conference, Sept 7-9, 2014, Tampere, Finland. Rajala, S., Kamppuri, T., Vehviläinen, M. and Kamppuri, T., Vehviläinen, M., Grönqvist,

Setälä, H. Regeneration of modified cellulose

S., Setälä, H., Maloney, T. and Rissanen, M.

into fibres. Poster presentation in FIBIC seminar,

Fabrication of wood cellulose – from pulp to

November 20, 2013, Espoo, Finland.

textiles: Biocelsol. Oral presentation in FIBIC seminar April 15, 2014, Espoo, Finland.

Waqar A., Kuitunen, S., Alopaeus, V. Modelling of xanthation kinetics during viscose process.

Nousiainen, P., Vehviläinen, M. and Rissanen,

Poster presentation in FIBIC seminar, November

M. Enzymatic Modification of Pulp Cellulose

20, 2013, Espoo, Finland.

to Regenerated Fibres and Films via Aqueous Alkaline Solutions. Oral presentation in The Third

Rajala, S., Kamppuri, T., Vehviläinen, M. and

Nordic Wood Biorefinery Conference, March 22-

Setälä, H. Regeneration of modified cellulose

24, 2011, Stockholm, Sweden.

into fibres. Poster presentation in FuBio seminar, August 27, 2013, Helsinki, Finland.

Rissanen,

Sustainable

Development

in Textiles. Oral presentation in Cristal –

Penttilä, P., Kilpeläinen, P., Tolonen, L.,

Sustainable development in lifelong learning,

Suuronen, J.-P., Sixta, H., Willför, S. and

June 6, 2013, Valkeakoski, Finland.

Serimaa, R. Effects of Pressurized Hot Water Extraction on the Structure of Birch Sawdust.

Sixta, H., Nousiainen, P., Vehviläinen, M.

Poster presentation. COST FP1105 13.05.2013 -

and Rissanen, M. From wood to structural

14.05.2013, Edinburgh, UK.

materials: Regenerated fibres for textiles and nonwovens. Oral presentation in FuBio seminar,

Penttilä, P., Kilpeläinen, P., Suuronen, J.-P.,

October 1, 2012, Espoo, Finland.

Willför, S. and Serimaa, R. Effects of pressurised hot water extraction on the nanoscale structure

Vehviläinen, M., Kamppuri, T., Rissanen, M.

of birch sawdust. Poster presentation. Physics

and Nousiainen, P. Cellulose regeneration from

Days, 14–16. 3. 2013, Espoo, Finland.

aqueous solution. Oral presentation in FuBio seminar, March 11, 2013, Turku, Finland.

FUBIO CELLULOSE PROGRAMME REPORT

Maloney, T., Grönqvist, S., Hakala, T.K., Hänninen, T., Penttilä, P., Kamppuri, T., Vehviläinen, M., Serimaa, R. and Suurnäkki, A. Pore Analysis of Dissolving Pulps. Poster presentation at the FuBio open seminar day, August 2013, Helsinki, Finland. Rissanen, M., Syrjälä, S. and Vehviläinen, M. Nousiainen P. Solubility and solution rheology of enzymatically treated pulp. Poster presentation at The Nordic Rheology Conference, June 8-10, 2011, Helsinki, Finland.

Theses: Penttilä, P. Structural Characterization of Cellulosic Materials Using X-Ray and Neutron Scattering, PhD thesis, University of Helsinki, 1.11.2013. Report Series in Physics HU-P-D207. Rajala, S. Regeneration of modified cellulose into fibres. Master’s thesis. Tampere University of Technology, 5.6.2013.

FUBIO CELLULOSE PROGRAMME REPORT

TEXTILE VALUE CHAIN RELATED TO FUBIO TEXTILE FIBRES

C O N TA C T P E R S O N Katja Salmenkivi, katja.salmenkivi@poyry.com

PA R T N E R S Kemira Metsä Fibre Pöyry Management Consulting Stora Enso Suominen UPM-Kymmene

FUBIO CELLULOSE PROGRAMME REPORT

ABSTRACT

The key objective was to provide information on market prospects, needed end-use properties, and value chain dynamics in order to help Finnish Bioeconomy cluster (FIBIC) partners focus their research investments on the most lucrative market areas. The project included a market assessment on textile and nonwoven fibres, as well as an analysis of the value chain structure and value creation in the apparel industry. As the largest end-user of man-made cellulosic fibres, the apparel industry is a high-potential application area for the FuBio Cellulose fibres Ioncell and Biocelsol. Despite a clear trend towards more environmentally friendly and natural fibres, the industry is very price conscious with constant pressure from brand owners to trim the supply chain. Fibres that offer technical or cost benefits compared to existing products thus offer the greatest potential for success. Successful entry into the apparel value chain calls for brand owner cooperation as early as possible in the development process. FIBIC partners should locate end users that are able and willing to engage in R&D cooperation and provide industry insights regarding potential applications and needed fibre properties.

Keywords: apparel, technical textiles, nonwovens, Ioncell, Biocelsol, man-made cellulosic fibres, market forecast, value chain

FUBIO CELLULOSE PROGRAMME REPORT

1. Work background

2. Objectives

The target market for the novel fibres

The objective of this work was to analyse

developed in the FuBio Cellulose programme

the market opportunities for novel cellulose

(Ioncell and Biocelsol) is the global market for

products in textiles and nonwoven applications

man-made cellulosic fibres. The increasing

and to analyse the value chain structure and

global demand for cellulosic fibres cannot be

value creation in the apparel industry.

met by cotton alone. In addition, there are serious drawbacks related to the conventional viscose process, namely the use of extremely

3. Research approach

volatile and toxic carbon disulphide (CS2) and a complex process configuration. The lyocell

Market

process yields fibres with higher strength

analyses were carried out as desktop studies

properties than other cellulosic fibres with an

complemented by external expert interviews

environmentally friendlier process. However,

when applicable. All market assessments

the solvent used in the process, NMMO, has

were conducted with close guidance from the

low thermal stability and there is an increased

industrial partners. The industrial partners

risk of runaway reactions. The FuBio Cellulose

also took part in workshops to define the

programme

novel

frameworks and scope of the studies as well as

processes for the manufacture of regenerated

in result reviewing and dissemination activities.

aimed

developing

jelmatunnukset superior to viscose fibres but with significantly

assessments

and

value

chain

fibres, which yield intrinsic fibre properties less environmental impact.

4. Results

Man-made cellulosic fibres are widely used

4.1 Textile fibre markets

in the textile and nonwoven markets. In the FuBio programme, Pรถyry analysed cellulosic

Synthetic fibres dominate the textile market

fibre consumption in three main segments:

with over 50% of annual fibre consumption.

apparel, technical textiles, and nonwovens.

Cotton is the most widely used natural fibre,

The apparel industry represents over 70%

representing approximately a third of all fibre

of all fibre markets and thus this overview is

demand (Figure 2). In 2011, consumption of

exclusively focused on the textile fibre market

synthetic textile fibres was almost 20 times

and apparel value chain (Figure 1).

higher than in 1970. The main reasons for this dramatic growth are the low production cost of synthetic fibres, the development of novel synthetic fibre grades and the limited supply of cotton fibre. Man-made cellulosic fibres constitute approximately 5% of global fibre production.

Figure 1. Scope of market and techno-economic analyses related to FuBio textile fibres.

FUBIO CELLULOSE PROGRAMME REPORT

Although

fibres

consumed. The majority of the projected demand

represent only a small share of global fibre

man-made

cellulosic

growth in textile fibres will be realized in the BRIC

consumption, they have several advantages

(Brazil, Russia, India and China) and booming

compared to cotton and polyester, such as

Asian countries, to which manufacturing is

feel, wearer comfort, softness, smoothness,

also relocating. Today, over half of all man-

moisture absorbency and capability for fibre

made cellulosic fibres are produced in China. It

modification. The most significant factor

should be noted that the apparel value chain

limiting the use of man-made cellulosic fibres

as a whole is more energy and labour intensive

is the price difference compared to cotton

than, for example, the chemical or automotive

and polyester. Price is typically the strongest

industries. Due to higher energy prices, higher

driver of fibre selection, although the effect of

labour costs, restricting legislation, numerous

trends and traditions cannot be underrated.

standards, and the complexity of EU policies,

The choice of fibre is always a compromise

European

between cost and fibre properties. Different

against developing countries. Fibre innovations

blends are generally used both to reduce

are therefore essential for business survival and

the manufacturing price of the garment and

research and development of man-made fibres

to modify textile properties such as pilling,

is concentrated accordingly in the industrialised

softness, washability, and durability.

countries. Europeâ&#x20AC;&#x2122;s long-term opportunity is to

producers

struggle

compete

form a hub of specialized fiber production, while The demand for textile fibres is estimated to

commodities would be produced in countries

grow along with population growth, GDP growth,

such as Indonesia, India or Brazil.

and a growing middle class with rising disposable income, among other trends. The more the

Although

GDP of a nation grows, the more textiles are

represent only a marginal share of todayâ&#x20AC;&#x2122;s

man-made

cellulosic

fibres

Polyester

Cotton Polypropylene Acrylics Polyamide Wool

PĂśyry Management Consulting Oy

Silk

Knitted and woven textiles

Other synthetics

Nonwoven

Viscose

Modal

Cellulosics Other cellulosic fibres

High purity nonwoven Micro-denier Flame retardant Hygiene products

Figure 2. Global consumption of textile and nonwoven fibres

FUBIO CELLULOSE PROGRAMME REPORT

total fibre production, there is one widely-

to suffer. The apparel industry is dominated by

known but disputed scenario that predicts

strong brands that dictate each step of the

strong

fibres

value chain. This has resulted in an industry

(Figure 3). This ‘cellulose gap’ scenario is built

ready to relocate, always seeking the lowest

on the estimation that one third of all fibres

labour cost countries.

growth

for

cellulose-based

should be based on cellulose materials due to their softness and moisture management

The key trends shaping the apparel industry

properties. ‘Gap’ refers here to the supply gap

include fast-moving fashion trends, mass

in cellulose-based fibres, to which current

consumption,

cotton production methods are unlikely to be

the sector, growing interest in environmental

able to respond. Cotton production uses over

sustainability, and increasing demand for

twenty times more water than viscose, needs

functional textiles. Global fashion trends are

four times more high-grade arable land and

defined by a small number of players (e.g.

is one of the largest markets for pesticides.

Peclers Paris), which the majority of brand

Although viscose fibres have traditionally had

owners

a significant price premium over cotton, this

supplying low-price, short lifespan products

cellulose gap would provide an opportunity for

are among the strongest drivers of mass

man-made cellulosic fibres, including FuBio

consumption and increasing homogeneity of

Cellulose fibres, as cotton substitutes.

the apparel industry.

The global textile market is highly dependent

Environmental

on the general economic situation. In weaker

consumerism have increasing influence in

conditions, apparel is one of the first segments

the textile industry, especially in the mature

160

follow.

increasing

homogeneity

Multinational

sustainability

retail

and

chains

ethical

Million tons

140

Cellulose Gap

120

MMCF

100

Cotton

80 60

Synthetic Fibres

40 20

Wool

0 1900 1920 1940 1960 1980 2000 2005 2010 2015 2020 2025 2030

Pöyry Management Consulting Oy 1. Modified from

Figure 3. Cellulose gap scenario1.

‘The Cellulose Gap’ by Gherzi, Feb 2011

FUBIO CELLULOSE PROGRAMME REPORT

markets. Green products are gaining ground

harvesting and protection during transport.

but remain niche, as the majority of consumers

Downstream

are unwilling to pay a premium. One means of

substantial amounts of chemicals, including

justifying premium pricing and ensuring that

dyes for colouring and different finishes and

products live up to environmental and ethical

preservatives for ready-made garments.

processing

also

consumes

standards is labelling. One of the most wellknown labels in the textile industry is the Oeko-

The apparel value chain studied in the FuBio

Tex Standard, a globally uniform testing and

Cellulose programme starts with pulp and

certification system for textile raw materials,

cellulose

intermediate and end products at all stages of

distribution and sales. In this overview, the

production. The importance of these standards

beginning of the value chain is limited to viscose

and labels is emphasized with apparel items

and lyocell fibres. After fibre production the

that are in close contact to sensitive skin, such

fibre is spun into yarn, which is woven or knitted

as underwear and children’s clothing.

into a fabric and usually treated with finishing

fibre

producers

and

ends

with

chemicals. Finishing can be also done after Increasing demand for functional apparel is

garment manufacturing or in both steps. Each

interlinked with the development of technical

step in the value chain, from pulp to garment

textiles and materials. Functional textiles

manufacture, can be performed separately or

include smart features, such as responding to

be partially or wholly integrated (Figure 4).

variations in body temperature and absorbing heat and body moisture to give the clothing a

Distribution and sales can be roughly divided into

comfortable, dry feel. A common example is

two parts: the ‘traditional apparel value chain’,

the Gore-Tex fabric.

where retailers buy ready-made garments from garment manufacturers with little influence

4.2 Apparel value chain

on the value chain and the products, and the ‘new apparel value chain’, which is controlled by

Despite considerably varying end product

strong multinational brand owners.

requirements, textile supply chains share numerous close similarities and the apparel

The number of operators increases significantly

industry as a whole can be described using

towards the end of the apparel value chain

a single generic supply chain. The supply

(Figure 5). In the pulp production step there

chains all use similar raw materials, which

are only tens of operators, while in the retail

are further treated processed to gain specific

step there are tens of thousands of operators.

characteristics. Most differences therefore

Pulp producers are often forward integrated

occur at the consumer end of the chain. In the

with fibre producers due to demanding quality

apparel industry, retailing plays a significant

parameters, which makes switching costs

role in distribution, whereas technical and

notable resulting in notable switching costs

industrial textiles are typically a business-to-

between suppliers or fibre types. Also, barriers

business market. The textile industry is strongly

to entry are substantial in the dissolving pulp

connected to the chemical industry throughout

industry, for example, due to high investment

the chain, from fibre to finished product. The

costs of new plants, know-how issues and the

production of man-made fibres is an entirely

length of the product approval process.

chemical process, and many natural fibres require substantial amounts of pesticides,

Viscose fibre production is heavily concentrated

fertilizers and other chemicals for cultivation,

in China, with large companies dominating the

FUBIO CELLULOSE PROGRAMME REPORT

Synthetic fibre producer Cotton, wool, silk etc. producer

Wholesaling by brand owner

(Viscose staple) fibre producer

Pulp producer

Weaver/ Knitter

Spinner

Finishing

Distribution and sales by Brand owner or Retailer

Garment manufacturing

Design, marketing, advertising, supply chain management

Integrated dissolving pulp and viscose production (e.g. Birla) Integrated from the production of fibre to garment (Toray)

Integrated from yarn spinning to garment production (e.g. Bombay Rayon Fashions, Arvind) Integrated from yarn spinning to weaving/knitting (e.g. Weiqiao, Alok Industries, Toyobo, Huafu)

Pöyry Management Consulting Oy

Integrated from fabric manufacturing to retail (e.g. American Apparel)

Figure 4. Integration of operations within the apparel value chain.

Amount of operators

• Low investment costs make it easy to establish new operators if needed • Tens of thousands of operators

• ~30 Operators

Pulp producer Source:

• Thousands of operators.

• Focus in production is in China and rest of Asia

• Strong consolidation trend

•Strong consolidation trend

• Can be done by same operator as fabric or garment

• Tens of thousands of operators both in retailing and brands. • Some strong brands are more significant than others and drive the consumption.

• Focus in production is in Asia

• Less than hundred operators

Fibre producer

Spinner

Weaver/ Knitter

Pöyry, Interviews

Finishing

Garment manufacturing

Distribution and sales Pöyry Management Consulting Oy

Figure 5. Number of operators in the apparel value chain.

FUBIO CELLULOSE PROGRAMME REPORT

market. In addition, China also accounts for the

and industry changes are driven by a

bulk share of global viscose demand. The number

handful of a relatively small pool of strong

of yarn manufacturers, weavers and knitters is, on

and influential global brands. Brand owners

the other hand, substantially larger compared to

rarely own production capacity as it offers

fibre producers. The industry includes hundreds

no competitive advantage, and contracts

of large companies and thousands of operators,

between garment manufacturers and brand

which are mainly located in China and the rest

owners tend to be short-term.

of Asia (Figure 6). Finishing is usually done by the same company as the weaving or by the

The vast majority of apparel industry companies

garment manufacturer if finishing is applied to a

are affected by fashion trends driven by strong

ready-made garment. Overall, there is a strong

consumer brands. These trends are transferred

consolidation trend throughout the fibre industry.

to yarn and fabric manufacturers through demand for certain types of products. Trends

Garment manufacturing has notably more

rarely impact fibre selection directly, since

players than the previous steps in the value

brands are unlikely to commit to a specific fibre

chain. The industry is very labour intensive

type. However, trends can have an indirect

and characterized by high cost competition.

effect on fibre demand. For example, a new

Relocating a garment manufacturing company

trend for glossy garments will increase demand

is relatively cheap and easy, which is one of

for viscose in fibre blends. The freedom to

the reasons why the industry is in constant

switch between fibre materials also serves as a

search of new locations with readily available

dampener against price volatility. If, for example,

cheap labour.

cotton is readily available at a reasonable price, 100% cotton fabrics are used. If the cotton

There are tens of thousands of operators in

price soars, production costs can be easily cut

apparel distribution and sales. Consumption

by using blends of lower-cost fibres.

General retailer Brand retailer Garment manufacturer Weaver Spinner Fibre producer Pulp producer Pรถyry Management Consulting Oy

Figure 6. Geographical distribution of key companies in each step of the value chain.

FUBIO CELLULOSE PROGRAMME REPORT

The bargaining power of big brands is

of integrated brand owner retailers further

overwhelming compared to suppliers, with

illustrates the global success stories of the

practically no switching costs incurred in

rapidly growing ‘fast retailing’ companies such

changing suppliers. The gap in bargaining

as Inditex and H&M. Despite fierce competition

power is not likely to narrow, rather the

in apparel retailing, the big players are able to

opposite, which has an impact on the

run their operations with reasonable margins.

profitability of all players in the upstream value chain. Table 1 summarizes the competitive

The profitability of non-integrated companies

position of different operators in the apparel

located in the middle of the value chain

value

analogy

(fibre, yarn, fabric, and garment) is generally

illustrates how different parts of a value chain

lower than that of companies at the ends of

operate with different cadences, or at different

the chain. Some vertically integrated apparel

inherent clock speeds. In studying a long value

manufacturing companies have, however,

chain it is not only important to know the speed

reported relatively high profits. Although the

of its different parts, but also to understand the

number of fibre producers is significantly

key criteria determining this speed.

lower than that of apparel manufacturers,

chain.

The

‘clock

speed’

the value created by non-integrated fibre Integrated brand owner retailers are the most

producers is rather poor. This can be partly

profitable players in the value chain, which

explained by high raw material costs, strong

emphasizes the strong position of brands in

competition and low switching costs between

the apparel industry. Companies with strong

different fibre types, resulting in poor pricing

brands have strong bargaining power towards

power. Pulp and integrated pulp and fibre

their suppliers and can sell their products

producers, on the other hand, have recorded

with higher margins. The high profitability

solid financial results.

Table 1. Competitive position of operators in the apparel value chain. Pulp producer - Wood price and availability Key bottlenecks determining competitive position

Fibre producer - Pulp price - Price of competing fibres

- Cost - Price and price competitiveness variability of - Technology cotton advantage - Quality - Wood (compared Sources of power procurement to synthetic & profits fibres)

Clock speed

SLOW

(Investment cycle, (Investment raw material price) cycle)

Spinner - Competing yarn producers - Changes in material price/ availability (depending on flexibility & specialization)

Weaver/knitter - Competing fabric producers - Changes in material preferences (depending on flexibility & specialization)

Garment manufacturer - Competing garment producers

Retailer (general)

- Strong - Competing bargaining brands, private and pricing labels of power of brand retailers owners - Threat of - Competing forward retailers integration of big garment manufacturers

- Lowest cost - Lowest cost - Lowest cost - Marketing producers have producers have producers have - Brand and an advantage an advantage an advantage position of the - Vertical - Differentiation - Vertical retail chain integration with high integration - Bargaining to increase quality fabrics power of large control and - Vertical retail chains power integration - Raw material flexibility FAST (Labour price, competitors, fashion)

FAST (Labour price, competitors, fashion)

Retailer (brand owner)

FAST (Category management, fashion, colour industry)

- Bargaining & pricing power through strong brand - Control over the whole supply chain

FAST (Fashion trends, colour industry)

FUBIO CELLULOSE PROGRAMME REPORT

4.4 Conclusions

heavy competition, especially on price and quality. Therefore, fibres that offer technical or

The apparel industry – the largest end-user of

cost benefits compared to existing products

man-made cellulosic fibres – is an attractive

offer the greatest potential for success. Overall,

application area for Ioncell and Biocelsol fibres.

integrated companies seem to have better

In addition, the proposed ‘cellulose supply

profitability than companies focusing on only

gap’ scenario would have most significance

one step of the value chain. A major challenge

in the apparel market where there is a clear

for many industry operators is the volatile price

trend towards more environmentally friendly

and availability of cotton, which has an impact

and natural fibres. On the other hand, the

on the entire market from fibre suppliers to

apparel industry is highly price conscious,

brand owners. The main bottlenecks for FuBio

with constant pressure from brand owners to

Cellulose fibre in the apparel value chain are

trim the supply chain. The market is dictated

related to politics and legislation, product quality,

by fashion trends driven by strong brands,

technology, and the fibre market (Table 2).

which also make most of the profit in the value chain. The beginning of the apparel value

Successful entry into the apparel value chain

chain, especially fibre production, spinning and

calls for brand owner cooperation as early as

weaving, is concentrated in Asia, whereas the

possible in the development process. FIBIC

end of the value chain (brand and retailing) is

partners should locate end users that are willing

located mainly in the West.

and able to engage in active R&D cooperation and provide industry knowledge and insights

Operations in the middle of the apparel value

regarding potential applications and needed

chain are integrated in various ways. In general,

fibre properties. Cooperation with Marimekko is

the value chain as a whole is characterized by

a major step in this direction.

Table 2. Main bottlenecks for FuBio Cellulose fibres in the apparel value chain. Politics / legislation

Security of supply for viscose producers in China has to be ensured before you can build a new cellulose based fibre plant. India and China can increase their protection of home markets thus making it impossible to export to these countries.

Product quality

If the FuBio Cellulose fibre is expected to be technically similar to viscose, the quality barriers are:

Wet strength is not good as for synthetic fibres Highest yarn uniformity Resistance to rubbing, abrasion, pilling No hydrophobic properties

Technology

A certain capacity is required to be able to get customers. There are no high switching costs in the value chain for FuBio Cellulose fibre if the technical quality is similar to viscose.

Market

The availability of raw material for fibre producer has limited the production (dissolving pulps). The volatile price and availability of cotton affects the whole fibre market. Fashion trends can benefit or hinder the demand of the fibre.

FUBIO CELLULOSE PROGRAMME REPORT

5. Exploitation plan and impact of the results The work provided its industrial partners with

programme. The results clarified both the

important information on market prospects,

market potential and barriers for the most

end-use properties, and value chain dynamics

promising products as well as the current

that can be used to evaluate the opportunities

supply and demand situation. The impacts

and risks entailed in entering these markets.

of the market analyses from the industrial

It also provided key recommendations and

partners’ viewpoint can be summarized as:

actions for achieving further development and market entry.

- increasing understanding of the markets

The results of the different market analyses

- increasing understanding of the value chains

relevant to the programme, and were communicated not only to the industrial partners in question but also to all researchers in the FuBio Cellulose programme. Based on

relevant to the programme

6. Networking

the overall results, successful market entry in the studied value chains requires proactive

The

cooperation with brand owners, as the brand

communication

market

owners are the key decision makers in all of the

and industrial partners by bringing the latest

studied value chains. In 2013, FIBIC organized

research information into the business arena.

a textile value chain workshop in which

As stated in the research plan approach, all

selected brand owners took part in evaluating

work tasks were carried out in close cooperation

the industrial importance and applicability of

between the industrial partners, research work

the FuBio Cellulose results. As a result, new

package leaders and individual researchers.

cooperation was initiated with several brand

Key results were communicated to industrial

owners and FIBIC industrial partners.

partners

and

assessments between

researchers

the

facilitated researchers

during

internal

work package meetings, FIBIC seminars, and According to the industrial partners, the market analyses

provided

essential

industrial partners’ internal meetings.

information

regarding the market prospects of the selected

Table 3 presents the roles of Pöyry Management

end-product areas of the Fubio Cellulose

Consulting and industrial partners in this work.

Table 3. Partner organizations and their roles. Partner

Role

Kemira

Industrial tutor. Defining and guiding the market assessments.

Metsä Fibre

Industrial tutor. Defining and steering the value chain analysis. Defining and guiding the market assessments.

Pöyry Management

Market assessment. Value chain analysis.

Consulting

Suominen

Industrial tutor. Defining and guiding the market assessments.

Stora Enso

Industrial tutor. Defining and guiding the market assessments.

UPM-Kymmene

Industrial tutor. Defining and guiding the market assessments.

FUBIO CELLULOSE PROGRAMME REPORT

7. Publications and reports Posters: Rouhiainen, J. and Salmenkivi, K. Value chains and value creation: Case apparel value chain. Poster presentation at the FuBio seminar, August 2013, Helsinki, Finland.

FUBIO CELLULOSE PROGRAMME REPORT

NEW PRODUCTS

C O N TA C T P E R S O N Jaakko Hiltunen, jaakko.hiltunen@vtt.fi PA R T N E R S Glocell Metsä Fibre Pöyry Management Consulting Stora Enso Suominen Tampere University of Technology University of Helsinki UPM-Kymmene VTT Technical Research Centre of Finland Åbo Akademi University

FUBIO CELLULOSE PROGRAMME REPORT

ABSTRACT The main focus was to develop novel absorbent cellulose materials for wiping and hygienic applications and thermoprocessable celluloses for melt-spinning and extrusion coating by industrially feasible methods. Furthermore, the aim was to produce functional beads from wood-based cellulose. A heterogeneous esterification process for producing thermomeltable cellulose esters from different pulp materials at high pulp consistencies (15-25 wt-%) was demonstrated. The targeted material properties, including good film forming ability and melt-spinnable formulations, were, however, not fully obtained, likely due to the inhomogeneity of the starting materials. Melt extrusion of the best synthesis materials by laboratory-scale twin-screw microcompounder was successful, indicating that these materials could be utilized, for example, in injection moulding processes. Commercial cellulose acetate butyrate showed very good spinnability in the melt spinning process; the mechanical properties were comparable to polypropylene fibres. The processability of the various commercial cellulose acetates in extrusion was good and polymer films with good quality were produced. Absorbent cellulose materials were easily produced at the kilogram scale. The results showed that drying of chemically modified fibres is challenging when the target is to maintain improved absorption properties. Hence, the drying process itself can be considered as a bottleneck in developing novel absorbent materials competitive with currently used superabsorbents and thus it needs further development. Processing of novel absorbent fibres by foam forming was feasible and the foam-formed absorbent fibres were suitable for making novel nonwoven structures by hydroentanglement. The absorbent fibres also provided improved water absorption and water retention capacities in the evaluated fluff pulp compositions. Physicochemically and chemically functionalized cellulose beads were prepared using an environmentally-friendly water-based solvent. HyCellSolv pretreatment was developed for making cellulose beads from different wood pulps. The method was successfully up-scaled to meet the demands of the semi-pilot scale bead machine. Functional cellulose beads were utilized as drug carriers. Drug delivery was studied with physicochemically modified beads, oxidized anionic beads and CMC-cellulose blended beads. All of the beads demonstrated high loading capacity and extremely good uniformity. In addition, controlled release from the beads was recorded with various active pharmaceutical ingredients (APIs). The cellulose beads and oxidized cellulose beads both showed excellent properties as drug carriers.

Keywords: absorbents, cellulose, cellulose esters, beads, extrusion, fluff, hygiene products, melt spinning, nonwoven, synthesis

FUBIO CELLULOSE PROGRAMME REPORT

1. Work background Industrial

cellulose

sustainable absorbent materials in different

derivatives are typically rather complicated

processes

for

making

application forms. Fluff pulp is currently widely

multi-stage processes consisting of different

used as an absorbent in feminine hygiene

activation, hydrolysis and purification steps,

products and nappies. The absorption capacity

depending on the nature of the reaction

of fluff pulp cannot, however, compete with that

and the targeted end-product properties. In

of commercial SAP materials. If the fluff pulp

addition, use of expensive high-purity pulps

absorption capacity could be increased, the use

is typically a prerequisite, especially for the

of SAPs could be reduced respectively. As SAP

production of thermoprocessable cellulose

materials generally produced from oil-based

materials. For these reasons most cellulose

polymers are significantly more expensive than

derivatives are too expensive to compete with

fluff pulp, even partial replacement of SAPs by

conventional polymers such as polypropylene

fluff pulp could positively affect both the cost

(PP), polyamide (PA) or polylactide (PLA).

and sustainability of the final product.

Simplification of the manufacturing process, reduced chemical consumption and use of

Fibre

cheaper raw materials are factors that could

nonwovens are typically synthetic PET and

enable significantly lower market prices for

PP combined with certain cellulose fluff

cellulose derivatives. Additionally, general wet-

pulp fibres. Rayon, once a common fibre in

lay methods for obtaining cellulose filament

nonwovens, has now been largely replaced

material have the problem of low productivity

by synthetic fibres. Synthetic fibre blends

due to a low spinning rate. Therefore, a spun-lay

are wet-laid along with cellulose for single-

process not using an organic agent is necessary

use fabrics. Growing concern regarding the

for obtaining low-environmental-load fibres

sustainability of disposables has led to the

using cellulose as a raw material. Known

creation of new biopolymer-based fibres

examples

industrial

materials

applied

disposable

thermoprocessable

that offer more environmentally responsible,

cellulose products applicable for melt spinning

performance-designed alternatives to the

are plasticized cellulose acetate and cellulose

traditional oil-based fibres currently used in

acetate butyrate (CAB). However, these fibres

nonwovens manufacturing today. In technical

are still mainly produced via spinning from

applications, synthetic fibres are also being

acetone solution due to the different challenges

replaced with natural fibre, such as hemp or

associated with their melt spinning.

coir. The challenge of using cellulose fibres in nonwovens is their cost compared to

High volumes of absorbent fibres and nonwovens

synthetic fibres. Thus, the identification of

are used in producing hygiene products. In

suitable end product applications is key when

addition, superabsorbents (SAP) are used in

aiming for increased cellulose incorporation in

high quantities in applications where high water

nonwovens.

absorption and/or water retention capacities are

needed. Crosslinked polyacrylates, which can

Cellulose and modified cellulose matrixes

typically absorb 40Â 000â&#x20AC;&#x201C;50Â 000% of distilled

can be used as carrier material for specific

water and 4000-5000% of 0.9% saline solution

functionalities and for their controlled release.

by weight, are commonly used as SAPs in

Cellulose beads, for example, can be used for

hygiene products. New and innovative personal

various chromatographic and ion exchange

care products require increasing amounts of

purposes. The challenge of functional cellulose

FUBIO CELLULOSE PROGRAMME REPORT

beads is their biodegradability and techno-

viability of the optimized materials in the

economic feasibility. Current solutions based

selected end-use applications.

on synthetic materials are, however, relatively expensive, which can provide a competitive

Thermoprocessable celluloses consisted of

edge for cellulose beads. In addition, benefits

novel cellulose esters and synthesized cellulose

can also be found in the ability to produce

ethers as well as commercial cellulose acetates

biocompatible and very pure cellulose materials

(CA) and cellulose acetate butyrates (CAB)

suitable, for example, for medical applications.

as reference materials. Absorbent cellulose materials were prepared at laboratory scale by grafting hydrophilic monomers and/or

2. Objectives

allylated xylan to allylated cellulose fibres by TEMPO oxidation of the fibres or by dissolution

The main objective was to develop i) functional

and coagulation of cellulose as bead particles.

cellulose bead structures from novel cellulose

Domsjö dissolving pulp was used in most cases

starting materials, ii) nonwovens with cellulose

as raw material, but high molecular weight

adsorbents aiming at minimum 4 000-5 000%

Borregaard dissolving pulp, never-dried kraft

water uptake for hygiene products and ii) extruded

pulp and Sigma’s commercial α-cellulose were

paper laminates and/or fibres from thermoplastic

also evaluated as raw materials. Mechanical,

cellulose for nonwoven structures. The work

enzymatic and/or chemical pre-treatments

aimed at demonstrating the performance of novel

were used as pulp activation methods to

cellulose-based materials in target applications

overcome the low pulp reactivity generally

and facilitating their feasibility evaluation in WP5.

associated with the Domsjö dissolving grade pulp. Synthetized products were purified before material characterizations in order to remove

3. Research approach

chemical

waste

and

unreacted

reagents.

Water absorption capacities were measured The focus was to develop novel absorbent

from air-dried and freeze-dried samples using

cellulose materials for wiping and hygienic

standardized methods.

applications and thermoprocessable celluloses for melt-spinning and extrusion coating by

Nonwoven

industrially feasible methods.

two alternative web forming methods. Base

samples

were

prepared

using

structures were prepared from reference Various routes for making thermoprocessable

materials

celluloses

using

and

cellulose

water-absorbent

and

air-laid

novel or

absorbent

foam-forming

materials processes

materials were evaluated and critical technical

and the applicability of these methods for

parameters for material development were

making controlled structures was evaluated.

identified and investigated. Optimization and

The intermediate structures were combined

up-scaling of the most potential syntheses

with a polyester web by hydroentangling on

were carried out and the material applicability

a lab-scale pilot line at Suominen Nonwovens

for the target end-use applications was

Ltd. targeting 50:50 blends of absorbent

evaluated. Economic evaluations were carried

material:polyester. The final samples were

out to support the material development and to

characterized (e.g. mechanical properties) and

illustrate the technical feasibility and economic

their performance was assessed against the

FUBIO CELLULOSE PROGRAMME REPORT

prepared reference materials, which imitated

flocculation

commercially existing products.

the cellulose concentration of the solutions,

conditions,

determination

functionalization of the bulk and surface of the Beside nonwoven structures, novel fluff pulp

beads, and control of micro- and mesopores

compositions with improved water absorption

and bead shape and size.

capacities for use, for example, in nappies were targeted. Fluff pulp is typically produced

Chemical modification of the cellulose beads

via hammer milling of cellulose web. The

can be done either before or after coagulation.

same method was also used to prepare fluff

Both methods were applied. Heterogeneous

pulps from foam-formed absorbent sheets. It

modification was studied more intensively

was expected that the foam-forming method

due to better stability and higher content of

would be more suitable for absorbent material

functional groups.

processing than conventional papermaking technologies.

absorption

To evaluate the applicability of cellulose beads

capacities and water retention capacities were

Finally,

water

as slow-release drug carriers, the native and

measured from the samples.

chemically modified beads were loaded with two model drugs, freely soluble (riboflavin

Melt extrusion and melt spinning of selected

5`-monophosphate

commercial and novel thermoplastic cellulose

hydrochloride

derivatives were carried out with a micro

soluble

compounder

and

laboratory-scale

active

sodium

salt,

monohydrate) pharmaceutical

and

lidocaine poorly

ingredients,

melt

APIs (griseofulvin and piroxicam). In addition,

spinning line. The spinnability was studied

anionic beads were loaded with a cationic

by increasing the take-up velocity. The as-

drug (Ranitidine HCl). Incorporation of model

spun filaments were separately hot-drawn in

drug substances was achieved by immersing

an oven instead of the heated godet on the

unloaded water-swollen beads in a solution of

melt spinning line due to the small amount

the drugs. In-vitro drug release with the loaded

of polymer used. The fibre properties were

and dried beads was performed according to

characterized by an optical microscope and

the USP paddle method. The drug content of

combined linear density and tensile tester

the beads and the amount of drug released

equipment. The target of the small-scale and

from them was investigated with a UV/Vis

pilot-scale melt extrusion trials was to assess

spectrometer to determine the loading efficacy

the processability of commercial and novel

and drug release mechanism. The drugs

thermoprocessable cellulose compared to

incorporated in the beads were investigated

currently used synthetic plastics, such as PP,

in the solid state with field emission scanning

and to produce continuous film and moulded

electron microscopy (FE-SEM) and Fourier

structures from novel thermoprocessable

transform

celluloses.

to determine the crystallinity of the drug

infrared

spectroscopy

(FTIR)

substances and the reasons for the different Cellulose

bead

structures

were

prepared

release profiles. The drug distribution in the

by dissolving cellulose in environmentally

beads was studied with a hyperspectral near-

friendly NaOH/urea solvent and coagulated

infrared (NIR) imaging device to clarify the drug

via the sol-gel process in anti- or non-solvent

release profiles.

using dropping or spinning drop atomization techniques. The bead structure design process included selection of flocculation media and

FUBIO CELLULOSE PROGRAMME REPORT

4. Results

The raw material used for syntheses had a very significant impact on end product quality;

4.1 Thermoprocessable cellulose materials

especially materials made from high cellulose molecular

weight

dissolving

grade

pulp

displayed very poor thermal melting, whereas 4.1.1 Synthesis and processing of materials

esters from commercial Îą-cellulose were very

Thermomeltable cellulose esters and ethers

homogeneous and resembled the commercial

were prepared using several synthetic routes.

references. The synthesis product quality

The aim was to obtain materials suitable for

was slightly improved by pre-treatments. The

applications such as melt spinning and extrusion

molecular weight (Mw) and polydispersity (PD)

coating. Cellulose esters with specific end-

of the materials were at the same level or lower

product properties were prepared up to the

than the references. It appears that uneven

maximum theoretical degree of substitution

distribution of acyl substituents caused by

(DS 3). At least partial melting of materials by

irregularities in the starting pulp materials and

hot compression was observed in most cases,

possible transglycosylation reactions may partly

but the homogeneity of the materials was not

explain the synthesis product heterogeneity.

fully comparable to commercial thermomeltable

The current methods for determining DS

cellulose

acetate

values are not able to distinguish differences

butyrates, which were studied as references.

in substitution between the crystalline and

Generally, cellulose hexanoates and cellulose

amorphous regions of cellulose. Especially in

laurates resulted in ductile melt-compressed

the case of mixed cellulose esters, the order in

translucent films when the degree of substitution

which the substituents are added to the pulp

was over 1.0. An example of the melt-compressed

cellulose can affect the end-product properties

film is presented in Figure 1. Mixed esters of

remarkably.

cellulose acetate hexanoates and cellulose

determined by the size of the substituent, and

acetate laurates typically contained a high

large acyl groups, such as laurate groups, may

number of acetate groups and only a low number

not be able to react with highly crystalline

of long-chain esters (degree of substitution, DS,

regions of cellulose due to steric hindrance. It

0.1-0.5). Figure 2 presents the DSC scans for

was observed that sequential and simultaneous

the sequentially esterified cellulose hexanoate

addition of acetate and long-chain fatty acid

acetate sample (DStotal 2.0).

substituents resulted in remarkably different

acetates

and

cellulose

Regioselectivity

typically

! Figure 1. Acetate laurate before and after melt-compressing at 200 Â°C. The formed film was transparent, homogenous and brittle.

FUBIO CELLULOSE PROGRAMME REPORT

Figure 2. DSC (1st and 2nd heatings) thermograms for the cellulose hexanoate acetate before and after thermal processing with a microcompounder at 200 °C . Thermal processing at 200 °C had no effect on the glass transition temperature of cellulose hexanoate acetate.

synthesis products. The order in which the acyl

resulted in a translucent but brittle sample

substituents were added was also critical for

(Figure 3A and 3B). Interestingly, the sequentially

the thermal behavior of a sample.

esterified (Hex-Acet) melt was possible to draw as a fibre by hand. The rod diameter decreased

The thermoplasticity and melt processability of

from 1.3 mm to a 0.1 mm fibre by drawing (Figure

the cellulose esters of hexanoate and laurate

3C). This indicates that the sequentially esterified

as well as the sequentially esterified celluloses

cellulose

(Acet-Hex and Hex-Acet) were tested with

suitable for the melt spinning process. Based

a twin-screw microcompounder at 170 and

on these observations, sequential esterification

200 °C. The cellulose ester was fed into the

enhanced thermoprocessability, unlike single

compounder and mixed for 5 min prior to

esterification.

hexanoate-acetate

(Hex-Acet)

forming a homogenous melt. The melt was extruded through a 2 mm diameter circular die.

Etherification of cellulose was not successful

For the cellulose esters 170 °C was generally

using the method implemented to a high DS

found to be too low a temperature to obtain

level (highest level achieved DS 0.3). The dry and

desirable melt formation. Good melt formation

hornified pulp sheets may require novel types

was obtained with all cellulose esters and

of chemical or mechanical activation, such

when the temperature was raised to 200 °C

as strong swelling and/or partial dissolution,

the esters exited the microcompounder in rod

before higher DSs and reaction efficiencies can

form. The cellulose hexanoate and laurate

be achieved using the etherification method.

samples were opaque and broke when bent. The

sequentially esterified celluloses showed better

Melt spinning of commercial thermoplastic

melt formation than the other cellulose esters.

celluloses

The sequentially esterified cellulose (Hex-Acet)

The quality of the synthetized materials

resulted in a translucent and ductile rod, whereas

was not sufficient for extrusion coating and

the sequentially esterified cellulose (Acet-Hex)

melt spinning processes and, therefore, only

FUBIO CELLULOSE PROGRAMME REPORT

Figure 3. The sequentially esterified celluloses processed at 200 °C: A) cellulose acetate hexanoate and B) cellulose hexanoate acetate (1.3 mm) and C) hand-drawn cellulose hexanoate acetate fibre (0.1 mm).

commercial materials were used for making

of both cellulose derivatives was typical of

demonstration products. The melt spinning

melt-spun fibres. The spinning temperature

trials were carried out with a laboratory-scale

had an influence on the mechanical properties

melt spinning line. Two commercial cellulose

of the CAB. The maximum tenacity value

derivatives, cellulose acetate (Plastiloid CA)

was 1.2 cN/dtex for fibres spun at 220 °C and

and cellulose acetate butyrate (Sigma Aldrich

only 0.4 cN/dtex for fibres spun at 240 °C.

CAB Mn 70 000), were used for the spinning

The tenacity values can be increased by hot-

trials. The spinnability of cellulose acetate

drawing. The maximum obtained tenacity

was poor. The broad melting point caused a

value of subsequently hot-drawn CAB fibre

considerable gas formation at the spinning

was 6.4 cN/dtex, which is comparable to

temperature (225 °C). The obtained filaments

melt-spun polypropylene fibres. The hot-

were weak and the maximum take-up speed

drawing trial as a spin-drawing process (with

was only 30 m/min. The filaments were thick

heated godets) was not as successful as the

(160 μm) due to the slow take-up speed and

subsequent process. The tenacity value of

low drawing of the filaments. Melt spinning

the CAB fibre was only 0.7 cN/dtex, indicating

of CAB was easier. Gas formation was rather

that optimization of spin-drawing process

low at the spinning temperature of 220 °C.

conditions (godet temperature, velocity, linear

The obtained filaments had better spinnability,

density) would be needed. In melt spinning, the

and the maximum tested take-up speed was

requirements for novel cellulose derivatives

800 m/min. The spinning trials showed that

are narrow melting temperature, stability at

the spinning velocity of CAB could be even

melting temperature, high molecular weight,

higher than 800 m/min. The diameter of the

and narrow molecular weight distribution. This

CAB filaments was about 25 μm, comparable

melt spinning work is one of only a few studies

to commercial textile fibres, but can be further

reported in the literature based on cellulose

decreased if needed. The visual appearance

derivatives.

FUBIO CELLULOSE PROGRAMME REPORT

4.1.2 Techno-economic modelling of thermoplastic cellulose

The

objective

evaluate

the

modelling

techno-economic

thermoplastic cellulose esters were well above

feasibility

was

the market prices of the fossil-based reference

of thermoplastic cellulose in melt-spinning applications.

The

thermoplastic

products PE and PP.

cellulose

materials of focus were cellulose esters,

The techno-economic modelling task also

more specifically cellulose-acetate-butyrate

included an analysis of how the projected

(CAB), cellulose-acetate-hexanoate (CAH) and

oil price development would alter the cost

cellulose-acetate-laureate (CAL). The modelling

competitiveness of the studied cellulose

scope for material and energy balances

esters. Although the correlation with oil price

and quantitative modelling was limited to

development is not as strong in the case of

thermoplastic cellulose granules. Common

cellulose esters as it is in the case of PP, PE or

melt spinning materials polyethylene (PE),

even PLA, increasing oil price will also increase

polypropylene (PP) and polylactic acid (PLA)

the price of thermoplastic cellulose. Therefore,

were selected as reference products (Figure 4).

increasing oil price is not expected to improve the cost competitiveness of cellulose esters

The commercial cellulose acetate process

considerably.

was used as a starting point for the modelled production concept (Figure 5). For all studied

Although the modelled production costs of

cellulose esters, raw materials constituted the

thermoplastic cellulose esters exceed the

largest part of the costs. The total production

prices of commodity polymers, the costs

costs and the share of raw materials decrease

are not prohibitive. Figure 6 summarizes the

with lower degree of substitution and with

strengths, weaknesses, opportunities and

higher share of acetyl groups of total acyls. In

threats of cellulose esters in melt spinning

this analysis, the modelled production costs of

applications.

End-use examples:

Modelling scope 1) Kraft pulp 1 2) Kraft pulp 2 3) Dissolving pulp 4) Sulphite pulp

Cellulose acetate/butyrate process

Thermoplastic cellulose structures (granules)

Melt spinning Film extrusion Moulding

REFERENCE MATERIALS Lignocellulosic feedstock / Sugars

PLA

Crude oil

VARIABLES 1. Electricity price 2. Oil price 3. Chemicals, concentration and price 4. Biomass price 5. Pulp price 6. Hemicellulose price

Pรถyry Management Consulting Oy

Figure 4. Modelling scope for thermoplastic cellulose esters.

FUBIO CELLULOSE PROGRAMME REPORT

Pulp Butyric/ Hexanoic/ Lauric acid

Acetic acid

Activation

Acetic anhydride Esterification

Stopping Anhydride prod Acetic acid

Waste water

Hydrolysis

Acid Recovery

Precipitation

Water

Washing

Water

Press & Drying

CAB/CAH/CAL Figure 5. Block-flow diagram of cellulose acetate derivative production processes.

Helpful to achieving business success Process related

Business environment related

Harmful to achieving business success

STRENGTHS

WEAKNESSES

•  Exis%ng commercial process (cellulose-‐acetate) as a pla6orm for a new product.

•  Product is not (and is unlikely to become) cost compe%%ve with currently used melt spinning polymers PE, PET, PP, PLA.

•  Would open melt spinning process for cellulosic materials.

•  Compa%bility/suitability of studied material for melt spinning process is unknown.

OPPORTUNITIES

THREATS

•  Demand for melt spinning products is increasing.

•  High subs%tu%on poten%al from compe%tors (PLA, Bio PE, etc.).

•  Possibili%es for improved product proper%es, and thus, new end-‐use applica%ons.

•  Nonwoven industry is very consolidated with only few players.

Figure 6. SWOT analysis of thermoplastic cellulose in direct melt spinning.

FUBIO CELLULOSE PROGRAMME REPORT

4.1.3 Markets and business opportunities for

an interest in non-food based bioplastics.

thermoprocessable cellulose

However, cost competitiveness remains a key

Market assessment of thermoplastic cellulose

challenge in all end-use sectors. Thermoplastic

concentrated on five selected application

cellulose materials should be aimed at higher

areas divided into two categories: “short-term

value applications instead of as a substitute for

cases”, which focus on large volume end-uses

commodity polymers, such as polyethylene or

where market entry is relatively simple, and

polypropylene.

“long-term cases”, which represent end-uses where market entry is more complicated or the

A blister can be defined as a local partition

product development time is expected to be

of a surface layer that causes a raised area

long (Figure 7). The short-term end-uses include

on a flat surface that can hold items. The

blister and other high-visibility packaging,

three main end-use segments for blister

shrink sleeve labels and films used in coated

and other high visibility packaging are food,

nonwovens, whereas long-term applications

pharmaceuticals and consumer goods, such as

include food contact packaging with strict

toys and tools. Blister and other high-visibility

regulation

requirements

cellulose

packaging meets current product marketing

nonwovens

through

direct

and

spinning

needs extremely well. Being able to see what

where the technical material requirements are

melt

you buy is still considered one of the most

challenging to meet.

important marketing instruments, particularly in consumer goods. Despite fierce competition

Generally, the market opportunities for the

in the packaging sector, blister and other high-

product groups studied are lucrative. All

visibility packaging is winning market share

examined markets are growth markets with

from other packaging solutions. Shrink sleeve labels are film tubes that are applied over the head of a container and shrunk to the container shape using heat, hot air or steam. A shrunk-on label can be applied just

Shrink sleeve labels

Food packaging

to the shoulders or to the cap of the container, or it can cover the entire product to give 100% promotional area. This possibility is of particular

Cellulose nonwovens through direct melt spinning Film coated nonwovens

importance in the food and pharmaceutical segments, where the amount of compulsory Blister and other high visibility packaging

regulatory

information

labels

ever

increasing. Shrink sleeve tubes can be used to label, for instance, glass and plastic containers, aluminium cans, contoured packages or chilled and frozen products. Shrink sleeve labels are high-profile promotional tools and the fastest growing labelling category.

Pöyry Management Consulting Oy

Approximate market size

Figure 7. Selected application areas for the thermoplastic cellulose market assessment.

The film-coated nonwoven market is extremely performance oriented. Film is applied on top of the nonwoven to gain properties unattainable by the nonwoven or film on its own. Performance

FUBIO CELLULOSE PROGRAMME REPORT

depends on the chemical formulation, coating

owners outsource their entire packaging function.

thickness and weight, the number of layers, the

The largest companies by turnover are found at

form of the technical textile and the nature of

both ends of the value chain, whereas the middle

any pre-treatments. Currently, there are very

is characterized by a large number of small

few bio-based materials in use in the coated

and highly specialized producers. Raw material

nonwoven market. Increasing environmental

producers and brand owners create most value in

concerns are generally tackled by reducing

the high-visibility and blister packaging sectors.

material consumption or replacing harmful

The magnitude of the captured value varies

substances, such as PVC.

between end-use industries.

Food packaging is a promising market for bio-

The blister market is highly price conscious,

based materials, but also challenging due

and there is little or no willingness to pay a

to strict food contact regulations. Material

premium for bio-based packaging in large-

requirements depend strongly on both the

scale applications. New bio-based materials

packaging design and the type of food. For

should be compatible with existing converting

instance,

very

equipment, as there is low interest in developing

different packaging requirements from chilled

and investing in new converting lines. The food,

ready meals. Changes in the global diet towards

pharmaceutical and toy industries have strict

more meat and dairy are having their effect on

laws and regulations, making market entry

the food packaging market. Overall, the market

more difficult. However, the market is large

is strongly driven by consumer behaviour.

and growing with a growing packaging trend

confectionery

boxes

have

towards more sustainable solutions. Spunlaid nonwovens and bioplastics are the fastest growing segments with compound average growth rates of (CAGR) almost 10% per annum. Annual growth rates of both shortand long-term end uses are summarized in Figure 8. Today, cellulosic fibres cannot reach almost half of the nonwoven market due to technical incompatibility. Direct melt spinning makes possible the combination of fibre production, web-forming and web-bonding in a continuous single-step process with much lower production costs and enhanced efficiency than, for example, in viscosebased nonwovens. However, the technical fibre properties are challenging to meet with cellulose-based thermoplastics. The value chain analysis looked at the blister packaging value chain, which starts with the raw material producer and plastic manufacturer and continues with converter, brand owner and retailer. The converter and brand owner can be horizontally integrated and, in some cases, brand

FUBIO CELLULOSE PROGRAMME REPORT

Spunlaid nonwovens Bioplastics, total Film coated nonwovens Shrink-sleeve labels Bilster and other high vis. Packaging

Shortâ&#x20AC;?term

Packaging, total Food packaging PĂśyry Management Consulting Oy

Longâ&#x20AC;?term 0%

10%

Annual CAGR

Figure 8. Annual compound average growth rates of selected end-use markets.

4.2 Cellulose beads

the beads with different pore size distributions and surface areas (Figure 10).

4.2.1 Preparation and application of cellulose

Beads prepared from 5% cellulose solution

beads

in 2 M HNO3 at 25 °C were oxidized by the Preparation of physicochemically designed

TEMPO/NaClO2/NaClO

system.

The

main

beads and anionic beads

oxidizing component (NaClO2) had a molar

HyCellSolv pretreatment was developed for the

ratio of ~1.2 per anhydroglucose unit (AGU) of

production of cellulose beads from different

cellulose. Oxidation with the TEMPO/NaClO2/

wood pulps. Dissolving pulp was pretreated with

NaClO system yielded higher charge than with

acidic ethanol liquor (HyCellSolv-liquor) using

meta-periodate or blending with CMC and

different treatment times and temperatures

the beads were also more stable. The highest

(Figure 9). After 2 h at 75 °C the pulp was

charged measured for the oxidized cellulose

soluble in 7% NaOH-12% urea-water so that

beads was 1848 μmol/g.

the solution was clear without undissolved fragments. Cellulose was thus dissolved in

Beads as drug carriers

water-based

The applicability of cellulose beads as slow-

solvent

without

undissolved

fragments after HyCellSolv pretreatment.

release drug carriers was evaluated by loading the native and chemically modified beads with

By controlling the coagulation kinetics it was

two model drugs, freely-soluble (riboflavin

possible to physicochemically functionalize

5`-monophosphate

cellulose beads. A 4-6% cellulose solution was

hydrochloride

coagulated dropwise in nitric acid of different

soluble

temperatures and concentrations, as well as

APIs (griseofulvin and piroxicam). In addition,

in salt water. Physicochemical modification by

anionic beads were loaded with cationic drug

controlling the coagulation kinetics provided

(Ranitidine HCl). Figure 11 describes the loading

active

sodium

salt,

monohydrate) pharmaceutical

and

lidocaine poorly-

ingredients,

Figure 9. Degree of polymerization as a function of time and temperature. Optical images demonstrate the dissolution mechanism in diluted CED solution.

FUBIO CELLULOSE PROGRAMME REPORT

Figure 10. Effect of (A) temperature, (B) acid concentration and (C) cellulose concentration on specific surface area of the CPD cellulose beads. General coagulation conditions were: 5% cellulose solution coagulated into 2 M HNO3 at 25 째C.

UV/Vis Content Analysis

Empty water swollen beads

Dried and loaded beads

Loading and drying at room temperature

Swollen CBs crushed and immersed into 10 ml water solution and stirred for 24h

Surface and Interior Morphology

FE-SEM & FTIR

Drug distrubition

NIR imaginig

Field emission scanning electron microscopy

(SPECIM MCT based Spectral Camera)

UV/Vis Drug release rate studies

Drug loading

- USP paddle method - 0.1 N HCI, @ 37, 100 RPM - 4-20 beads per vessel

Drying

Cellulose beads in drug loading solution

Figure 11. Unloaded and loaded drugs and their morphology.

FUBIO CELLULOSE PROGRAMME REPORT

procedure and characterization methods for

Cationic Ranitidine hydrochlorine was used as

the cellulose beads and presents FE-SEM

a model drug in a study of release profiles from

pictures of unloaded and loaded beads.

oxidized cellulose beads. The release profiles were noted to be constant regardless of the

Drug loading studies were performed with

bead charge, ambient pH, or bead swelling

various different compounds and several

rate. Compared to native cellulose beads,

types of CBs (different charge, porosity,

oxidized cellulose beads could carry twice as

etc.). Table 1 summarizes the loaded drug

much drug, and the drug was observed to be in

substances, cellulose bead types and drug

amorphous form. This property could be utilized

loading efficacies. Drug loading is dependent

for the delivery of poorly soluble substances.

on the concentration of the drug loading

Additionally, the loaded and placebo beads

solution, drug choice and the properties of

demonstrated high mass uniformity, indicating

the beads. Table 1 shows that drug loading

a good capacity for personalized dosing of

increased with high porosity and anionic

patients.

charge of the beads (for cationic drugs). CMC-cellulose beads with a ratio of 2:8 were The release of freely soluble drugs was

prepared using high DS CMC (DS 1.15-1.45). The

controlled with physicochemically designed

total polymer concentration of the solution

beads (Figure 12). In addition, the amount

was 5%. Reference beads (5% cellulose, no

of drug release was doubled with anionic

CMC) and CMC-beads were loaded with three

cellulose beads (Figure 13). However, the

different model drugs and the release profiles

release profile of poorly soluble APIs could not

of drugs and drug-polymer interactions were

be improved with beads due to shrinkage of

studied.

the beads during the drying stage.

Table 1. T1, T2 and T3 refer to different cellulose bead types with different physical properties (porosity; T3>T2>T1). CB=cellulose beads, RSP=riboflavin 5'-phosphate sodium, LiHCl=lidocaine hydrochloride monohydrate, Thp=anhydrous theophylline, Ran HCl=ranitidine HCl. Solubility of drug substances Freely soluble drugs

Drug substance

Type of CBs

RSP

Non-ionic CBs

LiHCl

Sparingly soluble drug

Poorly soluble drugs

Cationic drugs

Thp

Piroxicam Griseofulvin Ran HCl Quinine Sulphate

Drug content (%) T1

12.7

13.0

14.3

23.2

26.6

27.3

3.7

4.2

5.0

10.8

22.1

Anionic CBs Non-ionic CBs

20.1

16.1

Anionic CBs Non-ionic CBs

11.8

3.3

FUBIO CELLULOSE PROGRAMME REPORT

Figure 12. Release profile of RSP-loaded beads.

Figure 13. Cumulative release of Ranitidine HCl from non-oxidized (reference) and oxidized (20-60 °C) cellulose beads.

Anionic CMC-beads can be used to delay

They demonstrated high mass uniformity

drug release. Also, higher amounts of poorly

and high loading capacity. Drug release

soluble drugs can be incorporated in anionic

was constant, regardless of environmental

CMC-beads. The release profiles showed

changes, such as pH.

an initial “burst” release, mainly due to unbound drug, followed by a subsequent more

Adsorption of metal ions on beads

controlled release of bound cationic drugs

Cellulose beads contain acidic groups, which

from anionic CMC-beads. Also poorly soluble

were studied by potentiometric titration. The

drugs demonstrated controlled release after

titration data was evaluated by the FITEQL

an initial burst. This can be explained by slow

software, giving detailed information about the

diffusion and solubility.

different acidic groups on the cellulose beads and modified cellulose beads. Modified cellulose

Cellulose beads and oxidized cellulose beads

beads had more than ten times the amount of

have excellent properties as drug carriers.

acidic groups than cellulose beads (Figure 14).

FUBIO CELLULOSE PROGRAMME REPORT

Cellulose

Cellulose deriva8ve

Iontosorb 12

Volume added of NaOH (mL)

Poten5ometric 5tria5on

8 Blank

Cellulose

Cellulose deriva8ve

2 0

Poten8ometric 8tria8ons were performed for a cellulose sample , a cellulose deriva8ve with 3-‐sulpho-‐ h y d r o x y p r o p y l g r o u p a n d a cellulose with carboxylic func8onal group (Iontosorb).

Blank

Iontosorb 12

Volume added of NaOH (mL)

Cellulose

Cellulose deriva5ve

Iontosorb

lgK Concentra8on lg K Concentra8on Poten8ometric 8tria8ons were performed ellulose s2.7 ample , 94.3 a 2.8 for a c112.8 cellulose 4.5 deriva8ve 3-‐sulpho-‐ 6.8 with 5.4 17.9 h y d r o x y6.1 p r o p y l 2.5 g r o u p 9.6 a n d 4a 5.0 total 122.1 157.2 cellulose with carboxylic func8onal group (Iontosorb).

lg K

Concentra8on

3.7

750.6

4.7

538.2

8.7

25.4

1314.2

Table 5. Protona8on constants(lgK) and concentra8on (µeq/g) of acid groups of cellulose beads, cellulose deriva8ve and cellulose with carboxylic func8onal group.

Figure 14. Potentiometric acid titration for cellulose and cellulose derivative with acidic group.

Cellulose

Cellulose deriva5ve

lgK

Concentra8on

lg K

Concentra8on

2.8

112.8

2.7

94.3

Iontosorb

lg K

Concentra8on

3.7

750.6

The Domsjö dissolving pulp was treated with

4.2.2 Markets and business opportunities for

HCl and ethanol to4.5 eliminate any lignin residue. 6.8 5.4 17.9

cellulose beads 4.7 538.2

during 122.1 groups wastotal inserted preparation of 157.2 the

1314.2 particles with diameters in the micro- to

cellulose beads. The new modified cellulose

millimetre scale. Cellulose beads can be

Cellulose

can

with

6.1 3-sulpho-2-hydroxypropyl 2.5 9.6 45.0

Cellulose beads are porous spherical cellulose 8.7 25.4

Table 5. Protona8on constants(lgK) and concentra8on (µeq/g) of acid groups of cellulose beads, cellulose exchanger, with carboxylic func8onal group. becellulose usedderiva8ve as a and cation a unique functionalized

by introducing different organic

characteristic that can be used to achieve

or inorganic materials to the bead structure.

better and higher sorption. In these studies,

Depending

cellulose beads were used as a stationary

cellulose bead properties can range from, for

phase in column chromatography in order to

example, steady drug release to rapid water

study metal ion affinities. The mechanism is

absorption.

the

derivatization

agent,

mainly ion exchange by complexation of metal ions to the cellulose, which contains carboxylic

There are thousands of potential applications

groups as a functional group. It was observed

for cellulose beads with such functionalization

that divalent ions show better sorption than

capacity.

monovalent ions (Figure 15).

commercially

Cellulose

beads

available

for

have

been

15-20

years,

but annual production volumes are very Preparation of cellulose beads with acidic cellulose derivatives SO3Na Domsjö Cellulose

Cellulose

0,2

4,5

0,18

0,16

+ Urea + NaoH + Water

Cellulose derivative

O ONa

1 h to -15°C

Cellulose

0,12 0,1 0,08 0,06

Collected in 10% HNO3 Cellulose beads

K Li Na Ba Ca Mg Sr Cd Zn Ni Mn pH

0,14 C , mmol /L

Cellulose

3,5

3 2,5 2 1,5

0,04

0,02

0,5

100

120

140

160

180

200

0 220

V, mL

Figure 15. Preparation of cellulose with anionic cellulose derivatives (left). Concentration of metal ions in the collected fractions as a function of elution volume for a chromatographic column filled with cellulose beads (right).

FUBIO CELLULOSE PROGRAMME REPORT

small.

currently

advantages of cellulose beads in over 30 potential

used in niche applications such as ion-

Cellulose

applications were identified and innovated in the

exchange,

dye-ligand

screening stage (Table 2). These end-uses could

interaction,

be divided into four main categories: consumer

exclusion

beads driven by business-to-consumer (B2C)

chromatography, filter material and core-

markets, industrial beads driven by industrial

particles for pellets. In the market assessment,

B2B markets, chemoactive beads, which refer

the objective was to identify potential end-uses

to laboratory-related end-uses, and “jokers”,

for cellulose beads (both existing and novel)

which can represent any end-use but with a

and to analyse which of these seemed the most

higher degree of unconventional elements.

favourable for commercial bead production.

The majority of the identified bead applications

chelating

chromatography, affinity

beads

are

sorbents,

hydrophobic

chromatography,

size

were related to industrial end uses. The screening of possible applications was based primarily on the unique properties

The

of cellulose beads, i.e. identifying end-uses

based on three criteria: (i) market potential

identified

end-uses

were

prioritized

where cellulose beads could offer significant

(including reference market size and annual

advantages compared to competing solutions.

growth), (ii) margin between reference price

Key properties for cellulose bead competitiveness

of competing solution and estimated cellulose

include mechanical stability, narrow particle

bead production costs, and (iii) applicability of

size distribution, high chemical resistance and

cellulose beads in a given end-use. As a result,

compatibility with most commonly used solvents,

eight potential end uses were ranked as hitting

high temperature stability, high selectivity of

the “sweet spot” with good market potential,

separation, excellent flow properties, chemical

adequate margin and technical applicability

reactivity in derivatization, non-toxicity, high

for the target end-use. These most interesting

porosity and large surface area.

applications included active food packaging, solid-phase synthesis support, composites,

In the market assessment reference markets,

feed additives, cosmetics, growth mediums,

key drivers, annual growth rates and competitive

plaster and dietary supplements (Figure 16).

Table 2. Potential end uses for cellulose beads. Potential end uses Chromatography

Composites

Acoustic boards and panels

Metal ion-exchange and water treatment

Growth medium

Smart sponges

Protein immobilization

Pollution recovery, e.g. oil

Light-adjusting paint

Cosmetics

Water damage clean up

eInk Lite

Air purification

Oil-water emulsion aid

Bending/origami sheet

Drug loading and release

Plaster

Reactive textiles

Ammunition

Active food packaging

Cellusensors

Dietary/ nutritional supplements

Mixing with CMC

Cellubots

Fertilizers

Absorbents

Cellubricks

Feed additive

Replacement of charcoal tablets

Swallowable perfume

Solid-phase synthesis support

FUBIO CELLULOSE PROGRAMME REPORT

grafting hydrophilic monomers and/or allylated xylan to activated cellulose fibres (Figure 17) or, alternatively, by TEMPO oxidation of fibres. In addition, blends of specific materials were also evaluated. Mechanically or enzymatically pre-treated dissolving pulps and bleached never-dried softwood kraft pulps (BNDS) were Figure 16. Eight end-uses were ranked in the â&#x20AC;&#x153;sweet spotâ&#x20AC;?.

mainly used as starting materials. Reaction efficiencies

cellulose

activations

were

low, with a typical degree of substitution for allylated fibres (DSallyl) of 0.05-0.10. TEMPO The majority of identified end-use opportunities

oxidation was more efficient with a degree of

were completely new applications as opposed

substitution for oxidized cellulose (DSoxidized)

to direct substitutes for existing products. All

of up to 0.2, which is close to the theoretical

in all, even if the required bead properties for

maximum DS. Unlike most other oxidative

a specific application were achieved, cellulose

reactions, TEMPO oxidation is highly selective

beads would still represent only a niche market

to primary alcohol groups. This decreases

for the forest industry. The greatest incentive

the maximum amount of carboxyl groups

for further development therefore most likely

introduced to cellulose drastically; however, it

lies outside the forest sector.

also enables oxidation without disrupting the crystalline structure of cellulose (Figure 18).

4.3 Novel absorbent materials for hygiene products

Absorbent

materials

were

freeze-dried

before analysis of their capacity to absorb 4.3.1 Preparation and application of absorbent

water and 0.9 wt-% NaCl solution. The water

cellulose materials

uptake values of the cellulose absorbent materials generally varied between 10-40

Production of novel absorbent materials

g water/g, with the highest values obtained

Various novel cellulose absorbent materials

with TEMPO-oxidized fibres, whose structure

were prepared at the laboratory scale by

was

subsequently

mechanically

loosened.

Figure 17. Preparation of novel cellulose absorbents by grafting hydrophilic monomers onto allylated cellulose fibre surface.

FUBIO CELLULOSE PROGRAMME REPORT

Glucose unit Oxidized glucose unit

TEMPO oxida,on Figure 18. Oxidation of surface anhydroglucose units of cellulose nanofibrils by TEMPO oxidation.

The mechanical loosening was a prerequisite

disintegration did not significantly improve the

for high water absorption capacity. Without

absorption capacity of the grafted materials.

mechanical treatment water-absorption values for TEMPO oxidized pulps were generally lower

Drying of absorbent fibres is crucial for

than 10 g water/g absorbent. The significant

preserving material performance. As freeze-

increase in water uptake capacity by light

drying may not be realistic at the industrial

mechanical treatment is apparently due to the

scale, the applicability of foam forming for

increase in available fibre surface. Even if the

the processing and drying of TEMPO-oxidized

chemical composition of the absorbents would

absorbent fibres was evaluated. The absorbent

favour very high water sorption, the sorptivity

properties of different structure types are

would remain low if the structure of the material

illustrated in Figure 19. Absorption capacity was

does not allow access of the water and swelling.

lowest for paper-like structures and highest for

The water uptake values of the grafted fibres were

porous and bulky freeze-dried structures.

maximum 15 g water/g fibre. Mild mechanical Improved (structural) absorption capasity

• • • •

100 % oxidized cellulose Foam-laid structure Air-laid drying Film structure

• • • •

Softwood & oxidized cellulose Foam-laid structure Air-laid drying Paper structure

• 100 % oxidized cellulose • Freeze-drying • Porous and bulky structure

Figure 19. Absorbent properties of different structures.

FUBIO CELLULOSE PROGRAMME REPORT

In addition to drying, further processing of

oxidized pulp were prepared. The aim was

the material is essential, especially when

to determine the optimum pulp composition

considering applications using fluff pulps. In end

for producing nonwoven base structures.

product (e.g. nappy) manufacture, a hammer

The target structure needed to have as high

mill is used for disintegrating the cellulose. In

water absorption capacity as possible. Foam-

the present small-scale studies, this process

formed sheets (80 g/m2) containing 80%

was simulated by dry blending the materials

softwood kraft pulp fibre and 20% TEMPO-

with a mixer. The results are shown in Figure

oxidized fibre were used. The foam-formed

20. Absorption capacity increased in the case

layers were combined with a polyester web

of foam-laid papers (target grammage 80 g/m2)

by hydroentangling, targeting 50:50 blends of

when the structure was dry blended.

pulp:polyester. As a reference, a pulp:polyester composition, using tissue sheets for the pulp,

Novel nonwoven structures

Novel

spunlaced

nonwoven

Dry-‐blended

was produced on the same pilot line.

structures

simulatingAbsortion commercial householdAbsortion wipes (50% polyester and 50% pulp) were produced [g/g] [g/g] in

Suominen pilot % / Consistency 0.5% 27 line. Both air-laid and foam / Consistency 2.0% technologies 28 forming were utilized in 18 making ation 4 absorbent cellulose sheet structures. Air laying Softwood 5was 0% suitable only for processing 16 19 pulp fluff Softwood 70% 20 25

The foam-formed structures provided a Grammage much [g/m2]stronger pulp:polyester nonwoven than the tissue-derived reference pulp. Also, the

decrease in wet strength was less for the foamformed product, even though all samples had

80 wet than dry strengths. The absorption lower 80

fibres, whereas foam forming was applicable

capacity was only marginally better with the

also for the production of sheet structures

foam-formed nonwoven compared to the

from novel absorbent materials, among which

reference. Both pulp-containing products had

TEMPO-oxidized fibres were identified as the

clearly lower absorption capacity than the 100%

most promising novel absorbent materials.

polyester nonwoven. The absorption capacity of the fibres does not translate directly into the

different

absorption capacity of the nonwovens, as a lot of

ratios of softwood kraft pulp and TEMPO-

the absorption is attributable to the void space

AbsorpIon [g/g]

Foam-formed

34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0

handsheets

with

Freeze-‐dried 27

Air-‐laid dried; not dry blended 28

Air-‐laid dried; dry blended

Target grammage 80 g/m2 25 19

Tempo oxidized cellulose 100% / Consistency 0.5%

Tempo oxidized cellulose 100% / Consistency 2.0%

Tempo oxidized cellulose 100%

Tempo oxidized cellulose 50% / SoEwood 50%

Tempo oxidized cellulose 30% / SoEwood 70%

Figure 20. Free swelling absorption capacity of cellulose-based materials when processing method was varied.

FUBIO CELLULOSE PROGRAMME REPORT

in the nonwoven structure. The pulp-containing

cellulose materials are given in Figures 21

products

product

and 22. According to the results, TEMPO-

compared to the 100% polyester nonwoven,

oxidized pulp did not improve the free swelling

which can be seen from the thickness of the

absorption capacity of fluff pulp and the

products at a given g/m2. Clearly, it is not enough

material performance was not comparable

to improve the absorption of the pulp alone; in

with commercial superabsorbents. However,

addition, the pulp needs to be in a favourable

gravity-based analysis may not be the most

nonwoven structure.

suitable method for determining absorption

make

much

denser

capacity. Improved fluff pulp

The applicability of TEMPO-oxidized pulp 0.9% NaCl-‐liuos

Correspondingly, the increase in absorption

for improving fluff pulp water absorption

capacity under load was enhanced by 40%

properties

when 100% fluff was compared to 100%

was

evaluated.

Besides

water

absorption capacity, also water [g/g] retention [%]TEMPO. [g/g] A range of different SAP grades are

Fluff 100% capacity, which is highly important 22 for many available, and when comparing the absorption Tempo 100% 19 of the TEMPO-based solution to the hygiene products, was characterized. Different -‐100 under load /m2 Fluff reel commercial & Foam coated T empo 2 .5% 22 0 superabsorbents were used as commercial bio-based SAP, the difference was Fluff 50% / Tempo 5materials. 0% reference Foam-formed and22air-dried 0 only 25%, as seen in Figure 22. Fluff 50% / SAP 50% 33 50 TEMPO-oxidized handsheets were defibrated Commercial SAP / Fubio 44 100 together with fluff pulp using a hammer mill. The applicability of the novel fluff pulp ORB T7061 Commercial SAP BASF HYSORB T7061 40 82 40 Alternatively, TEMPO-oxidized fibres were in a hygiene product application was Commercial Bio-‐based SAP 30 36material 30 applied onto a fluff pulp web using a semi-pilot

demonstrated at Delipap Oy. The target was

scale coating device. The oxidized cellulose

to demonstrate the potential of bio-based

containing fluff reel was also defibrated by a

absorbent material – oxidized cellulose – in a

hammer mill before material evaluation.

product application. The reference material was conventional fluff pulp used in different

The results of the gravity-based analysis of

kinds of hygiene products. Foam coating was

the absorption capacity of the absorbent

used as the coating method and the Surface

AbsorpJon [g/g]

40 33

35 30 25

20 15 10 5 0

Fluff 100% Tempo 100% Fluff reel & Fluff 50% / Fluff 50% / Commercial Commercial Commercial Foam coated Tempo 50% SAP 50% SAP / Fubio SAP BASF Bio-‐based Tempo 2.5% HYSORB SAP T7061

Figure 21. Free swelling absorption capacity of absorbent cellulose materials.

FUBIO CELLULOSE PROGRAMME REPORT

29 20

40 34

36 32 AbsorpKon [g/g]

29 20

28 24

+ 60%

23 16

16 12

+ 40% 14

"Tempo vs. Biobased -‐ 25%"

8 4 0

Fluff 100% Tempo 100% Fluff reel & Fluff 50% / Fluff 50% / Commercial Commercial Commercial Foam coated Tempo 50% SAP 50% SAP / Fubio SAP BASF Bio-‐based Tempo 2.5% HYSORB SAP T7061

Figure 22. Absorption under load (0.3 psi) of absorbent cellulose materials.

Treatment Concept (Sutco) as the research

energy and chemicals. Chemical and catalyst

environment for the manufacture of oxidized

recycling rates and doses were the most

cellulose containing fluff reel. The product

uncertain

process

demonstration was carried out on Delipap’s

chemical

recycling

hygiene

The

impact on the production economics. The

demonstrated bio-based absorbent material

competitiveness of the studied absorbents

was a fluff reel containing 10% oxidized

compared to commercial superabsorbents is

cellulose. The product demonstration was an

fully dependent on the absorption capacity,

anatomically shaped panty liner. The results of

which at the time of the modelling case was

the production-scale demonstration indicated

inferior to commercial SAPs. The lower the

improved absorption capacity in the case of the

absorbent capacity, the higher volumes are

bio-based absorbent material.

required. Because in the modelling scope

products

production

line.

parameters. could

have

Successful a

major

bio-based absorbents were defined as direct 4.3.2 Techno-economic modelling of bio-

substitutes for SAPs, the quantitative modelling

based absorbents

showed poor economic feasibility.

The objective of the modelling task was to evaluate the techno-economic feasibility of

In the qualitative opportunity assessment, the

bio-based and fully biodegradable absorbent

technical availability, political and health-related

materials as replacements for fossil-based

feasibility, as well as the bio-based absorbents’

superabsorbents and to increase the use

compatibility with the forest industry value

of cellulose materials in absorbent hygiene

chain were all very positive, but challenges

products (Figure 23).

arose

from

the

absorbent

markets

and

technical feasibility. The technical feasibility of

The main cost factor in bio-based absorbent

the recycling processes, purification and drying

production was feedstock pulp, followed by

were still a major question mark. On a general

FUBIO CELLULOSE PROGRAMME REPORT

Figure 23. Block-flow diagram of bio-based absorbent production.

level, the hygiene industry is a challenging

difficulty in demonstrating and communicating

market that is difficult to penetrate due to

the environmental benefits. The pros and cons

the dominance of a handful of strong brand

of bio-based absorbents in baby nappies are

owners, the large number of major absorbent

summarized in Figure 24.

producers that are developing their own biobased absorbents, a limited willingness to pay bio-premiums in the bulk nappy market, and

Helpful to achieving business success Process related

STRENGTHS

WEAKNESSES

•  Bio and non-‐food based raw material, increase of bio-‐based content in nappies

•  Low absorp;on proper;es

•  Biodegradability •  Growing demand of all absorbent hygiene products

Business environment related

Harmful to achieving business success

•  Rela;vely simple process with high yields

•  Overall performance s;ll unclear: absorbent capability in absorbent core, mixing performance, bulkiness and ability to distribute liquids to prevent SAP gel blocking •  Unknown recycling and drying process

OPPORTUNITIES

THREATS

•  Increasing demand of eco-‐nappies

•  Bio-‐based SAP already entering the market

•  Possibili;es in other end-‐uses, especially as “improved ﬂuﬀ”

•  Development of pulpless core and other technology breakthroughs such as nanocellulose •  Contaminants of WP3 products s;ll unclear •  Absorp;on proper;es remain low •  Recovery process proves to be too expensive

Figure 24. SWOT analysis of bio-based absorbents in baby nappies.

FUBIO CELLULOSE PROGRAMME REPORT

4.3.3 Markets and business opportunities for

exceeded sales of baby nappies. Increasing

bio-based absorbents

time pressure has led to the development of,

Hygiene

absorbent

products

dominate

for example, pull-up training pants and heavy

the absorbent market. Today, over 80% of

adult incontinence products that can absorb

fluff pulp and over 90% of superabsorbent

more than five litres of liquid.

polymers (SAPs) are consumed in baby nappies, training pants, feminine hygiene and

There are four key trends shaping today’s nappy

adult incontinence products (Figure 25). Fluff

development:

pulp can also be found in airlaid, spunlaced and

demand for ultra-thin products and increasing

other nonwovens, whereas there are numerous

concern

specialty

superabsorbents,

have gradually started to demand more

for example in agriculture, cable wraps and

environmentally friendly products. Currently,

packaging.

there is a vast number of different solutions

end

uses

for

sustainability, product

convenience,

safety.

Consumers

on the market including thinner, lighter and Two in three mothers in the US view disposable

more efficient nappies with less raw materials;

nappies as a “necessary evil” and have expressed

combinations of re-usable cloth nappies with

concerns about the environment, but not at

disposable absorbent pads; nappies with bio-

the expense of convenience. Only a marginal

based materials and reduced carbon footprint;

consumer group uses reusable cloth nappies

and a variety of partly biodegradable nappies.

in the West, despite the fact that absorbent

Whether the emphasis is on bio-based content

hygiene products alone make up as much as

or biodegradability depends strongly on the

2-3% of all municipal solid waste in Europe1.

region

and

regional

end-of-life

solutions.

At present, there are no 100% bio-based or Overall

hygiene

biodegradable nappies on the market due to

products is driven by population growth, GDP

demand

for

absorbent

the lack of substitutes for several fossil-based

development, urbanization, ageing population,

components.

growing middle-class and increasing time pressure. For instance, in Japan, sales of

Almost all new hygiene product launches focus

adult incontinence products have already

on convenience. Examples include pull-up training pants, body-conforming stretchable

1 Edana Sustainability Report: Baby Diapers and Incontinence

products, adult briefs with flexible waist belts,

Products (2005)

To other applications 0.8 million tons

Fluff pulp 4.2 million tons

SAP 1.5 million tons

Nappies

3.4 million tons

4.6 million tons

Hygiene absorbent products 8.2 million tons

Feminine hygiene products 1.7 million tons

1.4 million tons

To other applications

Pöyry Management Consulting Oy

0.1 million tons

Adult incontinence products 2.0 million tons

Figure 25. Market volume of hygiene absorbent products.

FUBIO CELLULOSE PROGRAMME REPORT

and light incontinence products designed for

each representing about a third of the nappy

everyday use. Ultra-thin products are win-win

weight. In the past few years, the drive towards

solutions not only for consumers and brand

ultra-thin products has led to a completely new

owners, but also for retailers. These lightweight

nappy design, the “pulpless” nappy. Pampers

products

Drymax nappies are one example of such a

convenient to wear, require less space, bring

product, with an absorbent core consisting

savings in logistic costs and reduce waste. For

of SAP between nonwoven sheets instead of

retailers, ultra-thin products provide reductions

bulky fluff pulp.

are

comfortable,

in valuable shelf and warehouse space. The nappy value chain consists of component In recent years, product safety has become a

producers (such as fluff, SAP, nonwoven

top priority in the hygiene industry. Families are

and adhesive producers), converters, brand

concerned about, for instance, chemical safety

owners and retailers. There is a great deal

and possible traces of contaminants. Many

of horizontal integration in the value chain:

eco-branded products are therefore marketed

many brand owners are backward integrated

as “chemical free”, “containing less chemicals”,

to convert their own products, and more and

or “certified free from harmful chemicals”.

more retailers are launching their own nappy

Two such chemicals commonly perceived as a

brands. There are hundreds of operators in

possible threat or allergen are TBT (tributyl tin)

the nappy industry, and yet innovation and

and latex.

product development are led by only a few multinational converter/brand owners. Two

The evolution of nappy composition in Figure

leading brand owners, Procter & Gamble and

26 demonstrates how the introduction of

Kimberly Clark, represent together more than

more efficient and lower cost superabsorbents

half of all nappy sales.

has resulted in lighter nappies with enhanced performance, more superabsorbents and less

Environmentally friendly nappies are still a

fluff pulp material. A typical modern nappy has

very small, but growing, segment. In addition

roughly the same amount of fluff pulp and SAP,

to leading brand owners having their own

Mass [g/nappy]

Other

Adhesives

Elastic back ear

Tape PP

LDPE

10 0

SAP 1987

1995

2005

2011

Fluff pulp

Average nappy composition [g/pad]

Figure 26. Evolution of nappy composition 1987-20112.

FUBIO CELLULOSE PROGRAMME REPORT

Modified from Edana Sustainability Report (2011)

eco-brands sold at a premium price, there are

as a significantly cheaper raw material than

smaller players focusing on online retail with

typical high-purity dissolving pulps (acetate-

a significant market share of the eco-nappies

grade pulps) industrially used in cellulose ester

segment. Unfortunately, â&#x20AC;&#x153;greenwashingâ&#x20AC;? is a

production. The targeted properties for cellulose

major issue in the hygiene industry, and thus

esters, including good film-forming abilities

all environmental claims should be supported

and melt-spinnable formulations were not fully

by, for example, LCAs.

obtained, probably due to the inhomogeneity of the materials and the hot-pressed (by static

Nappy performance and absorbency are more

laboratory press) film structures, which always

than the sum of the individual materials. In

contained some visible clods. Melt extrusion

addition to superabsorbents, each absorbent

of the materials was, however, successful

core needs other materials (typically fluff

indicating that these materials could be utilized

pulp) to distribute liquid into the structure

e.g. in injection moulding processes. The

and preventing gel blocking. Because water

degree of substitution (DS) of the materials

molecules are attracted to superabsorbents by

was theoretically sufficiently high to provide

electrical charges, the absorbency is strongly

completely homogeneous melts and it can

affected by electrolyte concentration. When

be speculated that the uneven distribution of

salinity is the most important factor reducing

the ester substituents may be at least partly

the absorbency of superabsorbent polymers,

explained by the raw material quality and

pressure has a similar role to fluff pulp. Hence

heterogeneous reaction conditions. The results

superabsorbent polymers are not only needed

show the importance of raw material quality in

to increase nappy absorption, but also to hold

producing thermoprocessable materials.

the liquids under pressure. The melt spinning studies provided new

5. Exploitation plan and impact of the results

insights regarding the property requirements of novel cellulose derivatives. Melt spinning offers a more economical and efficient method compared to dry or wet spinning, which both

Heterogeneous synthetic routes for producing

need a polymer solvent and a solvent recovery

thermomeltable cellulose esters from different

system for the spinning line. The only main

pulp materials at high pulp consistencies (15-25

environmental impact of melt spinning is the

wt-%) were demonstrated. Etherification, which

energy required for extruder heating and

is typically carried out in aqueous conditions,

running the machine.

would

economically

attractive

and

industrially easy to adopt, but the experiments

Cellulose absorbent materials can be easily

showed that more basic research on cellulose

produced at kilogram scale, for example

reactivity and synthesis development will be

by TEMPO oxidation. The results showed

needed before sufficiently high degrees of

that drying of chemically modified fibres

substitution providing thermal melting of an

is challenging when the objective is to

end-product can be obtained. The esterification

maintain

route was more efficient than etherification,

The drying process can thus be considered

and thermomeltable cellulose esters were

as a bottleneck in developing novel absorbent

obtained from various pre-treated and non-

materials competitive with currently used

treated cellulose pulps. The main raw material

superabsorbents, and the technology therefore

was a dissolving pulp that can be regarded

needs further development.

improved

absorption

properties.

FUBIO CELLULOSE PROGRAMME REPORT

The preparation of air-laid nonwovens provided new information on the requirements of the different materials (fluff pulps and SAP) and how to optimize the process parameters, and highlighted key air-laying technology development targets. Cellulose dissolution is generally challenging and untreated pulps cannot be properly dissolved in aqueous alkaline solutions for cellulose bead production. Controlling the degree of polymerization and primary cell wall rupturing enables the use of weaker environmentally friendly solvents. Additionally, an opened structure increases the penetration of derivatizing reagents. Understanding the roles of the different factors involved in the preparation of cellulose gel-based products enables the design of cellulose beads for multiple purposes. Oxidation post-processing, blending and physicochemical design during bead coagulation are tools that can be utilized to target certain functionalities. The knowledge accumulated on process parameters and the control of basic properties enables wellestablished methods to be readily modified for other functionalities, such as protein/ enzyme immobilization. More research is, however, required to harness the full potential of cellulose beads. Pharmaceutical companies are increasingly using more sophisticated excipients and blends in order to defend against generic competition. Greater use of so-called functional excipients â&#x20AC;&#x201C; which go beyond the traditional role of excipients as a carrier for active pharmaceutical ingredients (APIs) â&#x20AC;&#x201C; is one of the key drivers for growth in the excipients market. The commercialization of cellulose beads might thus be more feasibly pursued via excipient manufacturers rather than pharmaceutical companies. Both commercialization routes should, however, be explored.

FUBIO CELLULOSE PROGRAMME REPORT

6. Networking The research was carried out jointly by industrial and research partners. Table 3 presents the research partners and their roles in this topic. Table 3. Partner organizations and their roles Partner

Role

Glocell

Qvantitative economic modelling

MetsĂ¤ Fibre

Industrial tutor. Providing industrial view insight to technoeconomic assessments

PĂśyry Management Consulting

Market study. Economic feasibility modelling. Business potential evaluation

Stora Enso

Industrial tutor. Steering of work related to thermoplastic celluloses, material supply. Providing industrial view insight to techno-economic and market assessments

Suominen

Industrial tutor. Preparation and testing of nonwovens, steering of experimental work. Providing industrial view insight to technoeconomic and market assessments

Tampere University of Technology

Extrusion coating and melt spinning of thermoplastic cellulose;

Materials Science

mechanical processing of fibres into nonwoven structures

University of Helsinki

Research adviser

Organic Chemistry UPM-Kymmene

Industrial tutor. Development of absorbent fibre materials, steering of experimental work related to hygiene products. Providing industrial view insight to techno-economic and market assessments

VTT

Syntheses and testing of thermoplastic celluloses and cellulose absorbent material

Ă&#x2026;bo Akademi

FCT: Dissolution of cellulose in water-based systems, preparation

Fibre and Cellulose Technology (FCT)

and functionalization of cellulose beads, tailoring of beads for

Analytical Chemistry (AC)

applications in different value chains.

Pharmaceutical Sciences (PS)

PS: Beads as drug carriers AC: Chemical analyses

100

FUBIO CELLULOSE PROGRAMME REPORT

7. Publications and reports Publications

Posters

Gericke, M., Trygg, J. and Fardim, P. Functional

Rissanen, M., Wikström, L. and Lahti, J. 2012.

Cellulose Beads: Preparation, Characterization,

Commercial thermoplastic celluloses in melt

and Applications, Chem. Rev. 113, 2013:4812-

spinning and extrusion coating, FuBio Cellulose

4836.

seminar, 1st October 2012, Espoo, Finland.

Trygg, J., Fardim, P., Yildir, E., Kolakovic, R.

Setälä, H. 2012. The use and preparation

and Sandler, N. 2014. Anionic cellulose beads

for drug encapsulation and release. Cellulose

hydroxypropyl substituents, 3rd International

21(3)2014:1945-1955.

Cellulose conference, Nov 8-13, 2012, Sapporo,

fibrous

celluloses

with

1-allyloxy-2-

Japan. Trygg, J., Gericke, M. and Fardim, P. 10. Functional Cellulose Microspheres, in Popa,

Trygg, J., Kuzmanovski, G. and Fardim, P.

V. (Ed.) Pulp Production and Processing: From

Up-scaling of cellulose beads manufacturing.

Papermaking to High-Tech Products, Smithers

Poster presentation in FuBio seminar, August

Rapra Technology, 2013.

27, 2013, Espoo, Finland.

Trygg, J., Fardim, P., Gericke, M., Mäkilä, E.

Kolakovic, R., Redant, H., Trygg, J., Gericke,

and Salonen, J. Physicochemical design of the

M., Fardim, P. and Sandler, N. Porous cellulose

morphology and ultrastructure of cellulose

beads in drug delivery – comparison of anionic

beads. Carbohydr. Polym. 93, 2013:291-299.

and nonionic systems. Poster presentation in FuBio seminar, August 27, 2013, Espoo, Finland.

Trygg, J. and Fardim, P. 2011. Enhancement of cellulose dissolution in water-based solvent

Arroyo, J., Trygg, J. and Fardim, P. Targeted

via ethanol–hydrochloric acid pretreatment.

applications

Cellulose 18, 2011:987-994.

Chromatographic column and drug release.

modified

cellulose

beads:

Poster presentation in FuBio seminar, October Yildir, E., Kolakovic, R., Genina, N., Trygg, J.,

2012, Espoo, Finland.

Gericke, M., Hanski, L., Ehlers, H., Rantanen, J., Tenho, M., Vuorela, P., Fardim, P. and Sandler,

Rissanen, M., Lahti, J. and Wikström, L.

N. Tailored beads made of dissolved cellulose

Thermoplastic celluloses in extrusion coating

- Investigation of their drug release properties.

and melt spinning. Poster presentation in FuBio

Int.J.Pharm. 456, 2013:417–423.

seminar, October 2012, Espoo, Finland.

Presentations

Theses

Setälä, H. 2012. Novel materials based on wood

Redant, H. Cellulose beads in drug delivery –

polysaccharides. BiPoCon 2012 conference,

comparison of anionic and non-ionic systems,

May 27-31, 2012, Siófok, Hungary.

M.Sc. Thesis, Åbo Akademi University 2013.

Setälä, H. 2012. Cellulose absorbents. FuBio Cellulose seminar, 1st October 2012, Espoo, Finland.

FUBIO CELLULOSE PROGRAMME REPORT

101

CATIONIC CELLULOSE BASED CHEMICALS C O N TA C T P E R S O N Jonni Ahlgren, jonni.ahlgren@kemira.com

PA R T N E R S Glocell Kemira Metsä Fibre Pöyry Management Consulting Stora Enso University of Helsinki University of Oulu UPM-Kymmene VTT Technical Research Centre of Finland

102

FUBIO CELLULOSE PROGRAMME REPORT

ABSTRACT

The high molecular weight biopolymers such as cellulose become more and more important when alternatives for synthetic polymer raw materials for water soluble chemicals are considered. Synthesis of uncharged derivatives such as hydroxyethyl cellulose and anionic derivatives such as carboxymethyl cellulose are currently used in different commercial applications e.g. as rheology modifiers and as process additives. On the other hand the products from cationic derivatives of cellulose are practically non-existent. Cellulose was used here as a raw material in the production of flocculating agents for paper and wastewater treatment applications. Cationic water-soluble polymers and cationic nanoscale particles were targeted. It was shown that a water-soluble derivative can be made only if sufficient charge density is achieved (about DS 0.5). Three interesting reaction routes to a cationic cellulose product were identified, each of which requires further development towards commercialization. It was shown that, in addition to dissolving pulp, also ordinary kraft pulp can be used as a raw material for polymer synthesis. Hemicelluloses need not necessarily be removed, and the cationic product quality is better if the pulp is not heat-dried before use. Softwood performed better than hardwood, although hardwood also showed good properties. The same cationic cellulose polymer is not suitable for all applications. Sludge dewatering prefers high charge density, whereas retention and other flocculation requires high molecular weight. The cationic particle performed relatively well in both applications. The cationic cellulose derivatives as such did not perform as well as polyacrylamide in sludge dewatering or in flocculation. In flocculation under high shear and in fixing applications, however, certain cellulose derivatives exceeded the performance of the polyacrylamide reference.

Keywords: cationic cellulose, cationic particle, cellulose betainate, CST, dissolving pulp, FBRM, GTAC, kraft pulp, market analysis, never-dried kraft pulp, techno-economic modelling

FUBIO CELLULOSE PROGRAMME REPORT

103

1. Work background Cationic

molecule, water solubility would be achieved

important role in many industrial and municipal

and its use as a flocculating polymer would

applications, such as in papermaking as

become possible.

flocculating

retention

aid,

polymers

different

have

wastewater

treatments as a flocculant, and in sludge

This has been demonstrated in the TEKES

dewatering. Increasing environmental concern

project,

limits the use of synthetic cationic flocculating

Papermaking

polymers, and alternatives to them are needed.

water-soluble derivatives were made from

One good option for this is cellulose.

cellulose. The derivatives were also tested in

Novel â&#x20AC;&#x201C;

Cellulose CelPlus,

Chemicals where

cationic

papermaking applications such as retention, Wood cellulose has one of the highest molecular

dewatering and pitch control. Optimization of

weights of all natural polymers, i.e. biopolymers.

the manufacturing process was not included

Cellulose is also widely available, being the most

in the scope of CelPlus. Thus, identification of

abundant annually renewable biomass on the

the optimum manufacturing method and its

planet. Cellulose also has an important role in

optimization were the main goals of the current

many industrial processes, such as paper- and

research.

boardmaking and fibre production. Although the main goal was to obtain a waterCellulose in its raw state is not water soluble

soluble

and has no cationic charge and thus requires

approach was also questioned. An alternative

cationic

cellulose

derivative,

this

modification before it can be used as a cationic

approach involving the production of a cationic

flocculating polymer.

derivative of nano-scale cellulosic particles was investigated to determine whether an efficient

Cellulose

derivatization

water-soluble

cationic flocculant needs to be a water-soluble

products has long been known. Uncharged

polymer. Both approaches were tested in

water-soluble derivatives such as hydroxyethyl

different applications at laboratory scale.

cellulose, hydroxypropyl cellulose and methyl cellulose, and anionically charged derivatives

The economic feasibility of the selected

such as carboxymethyl cellulose are used

processes

widely in different applications, for example,

to compare how successful the cellulose

as rheology modifiers and process additives.

derivatives would be commercially compared

Cationic derivatives are much less known,

to synthetic cationic polymers.

was

also

evaluated

order

and their commercial utilization is currently negligible. The cationic polymer market is worth close to $4 billion, with global production (excluding starch in papermaking) at around 1 million tonnes a year. It has been previously proven that cellulose can be made water soluble by introducing either non-ionic or anionic polar groups. If cationic groups could also be introduced to the cellulose

104

FUBIO CELLULOSE PROGRAMME REPORT

2. Objectives

4. Results

A new process for producing a cationized,

4.1 Used pulps

water-soluble, cellulose-based polyelectrolyte chemical product was to be developed, verified

Different native and pretreated cellulosic pulps

at initial pilot scale and modelled economically.

were used as starting material during the

The polymeric product was to be tested and

research. The aim was to find a pulp for chemical

benchmarked in selected applications as a paper

synthesis having high reactivity and resulting

and/or water processing chemical.

in a cationic polymeric end product of as high as possible molecular weight. In the cationic

Cationized cellulose nano-scale particles were

nano-scale particles the molecular weight of the

also to be developed in order to compare them

cellulose did not play as important a role.

to water-soluble derivatives. The used pulps and some of their properties are

3. Research approach

listed in Table 1.

4.2 Activation The research was divided into five Tasks: • Activation and molecular weight control

The aim of the activation research was to

• Evaluation of routes for water-soluble

investigate means of improving the chemical

cationic cellulose • Development of routes for water-soluble cationic cellulose

reactivity of cellulose and to evaluate how the improved activation leading to reactivity improvement could best be characterized. For

• Cationic particles from reactive milling

the latter, the most straightforward method was

• Application testing

considered to be a chemical derivatization itself.

In ‘Activation and molecular weight control’

the aim was to improve the reactivity of wood

simple

pulp cellulose. In ‘Evaluation of routes for

monochloroacetate,

water-soluble cationic cellulose’ the aim was

selected. Using this method it was concluded

to evaluate different routes for synthesizing

that

cationic cellulose derivatives for flocculants.

In ‘Development of routes for water-soluble

disintegrated in dry or wet form, and that

cationic cellulose’ the objective was to identify

isopropanol was the best performing additive

the two most potential synthesis routes and

in the reaction media.

model

derivatization

carboxymethylation

there reactivity

was

CMC

whether

reaction, using

synthesis,

significant the

sodium was

difference

cellulose

was

optimize them with the aim of upscaling one of the routes to the pilot scale. ‘Cationic

Different

particles from reactive milling’ was devoted to

activation and CMC reaction stages were also

cationic nano-scale particle synthesis. Most

studied. Use of microwaves gave a better reaction

of the product characterization work of the

result

samples and application testing were done in

reaction with ultrawaves performed the worst.

‘Application testing’.

Three different heating techniques, conventional

energy

than

sources

conventional

during

heating,

the

pulp

whereas

heating, microwaves and ultrasound, were thereafter used for CMC reaction with Borregaard and Domsjö dissolving pulp. There was no clear

FUBIO CELLULOSE PROGRAMME REPORT

105

Table 1. Used cellulose and cellulose pulps. nd=not determined. Cellulose starting material

Abbreviation

Bahia dissolving pulp Blue Bear Ultra Ether, Borregaard dissolving pulp Domsjö dissolving pulp after mechanical treatment

Mw (kDa)

Bahia

360

Borregaard

1700

Domsjö

410

DAc

550

Domsjö dissolving pulp after standard Biocelsol mechanical and enzymatic pre-treatment (see Chapter “Water based dissolution and regeneration processes”)

DENz

Domsjö dissolving pulp after novel mechanical and enzymatic treatment (advanced Biocelsol pre-treatment, see Chapter “Water based dissolution and regeneration processes”)

Dext

160

Enoalfa

Birch

HWNDHP

SWND

SWNDHP

880

Acetylated softwood never-dried hemi-poor kraft pulp

Ac-SWNDHP

Butylated softwood never-dried hemi-poor kraft pulp

Domsjö dissolving pulp after acetylation

Enoalfa, Enocell dissolving pulp, Stora Enso Bleached birch kraft pulp, Kaskinen Never-dried hemi-poor hardwood kraft pulp (birch) – freeze dried before use Never-dried softwood kraft pulp (hemicelluloses not removed) – freeze dried before use Never-dried hemi-poor softwood kraft pulp – freeze dried before use when used in DMAc/LiCl or HC DIT reaction systems

B-SWNDHP

Thermomechanical pulp

TMP

Microcrystalline cellulose

MCC

Methylated cellulose

MeC

Micro- and nanofibrillated cellulose

MFC

Sigma α-cellulose

nd 670

difference between the reactivity of the two

Chemical pre-treatment methods, such as

dissolving pulps despite their different origin and

acetylation, hydroxypropylation or methylation,

cellulose degree of polymerization (DP) when the

did not give satisfactory results in increasing the

same energy source was used.

reactivity of cellulose in cationization. Moreover, methylation seemed to disturb the cationization

Different activation parameters were further

reaction, probably due to competing for the

studied using the actual cationization, GTAC

same active hydroxyl sites. It was considered

synthesis (see Figure 1). Of the energy sources

that in certain cases hydroxypropylation could

studied, microwaves gave again the best

help improve solubility if it is done after the

reaction results. Disintegration, especially wet

cationization step.

disintegration, had a higher effect on GTAC

106

than CMC reaction. It was also shown that

Freezing of alkaline water treated cellulose to

CMC and GTAC synthesis have different NaOH

-40 °C with and without ZnO as an additive was

concentration optimums. No better additive

also tested as a pre-treatment method, but

than isopropanol was found.

was not found to improve cationization.

FUBIO CELLULOSE PROGRAMME REPORT

4.3 Water-soluble derivatives 4.3.1 Reaction route screening

other cationizations were made only in the

In the first phase several alternative reaction

homogeneous systems. Table 3 lists the used

routes to cationic, water-soluble cellulose

reaction systems.

derivatives were screened. Figure 1 and Table 2 summarize the approaches tested.

The reaction routes with highest potential were GTAC modification in a DMAc/LiCl homogenous

The GTAC method was studied in several

system and in a HC DIT heterogeneous

reaction

system, cationization of cellulose acrylate,

and

systems,

heterogeneous

reaction

efficiencies

both

homogeneous

systems, were

and

compared.

their The

and cationization of cellulose betainate. These reaction routes were further optimized.

Figure 1. The first six selected preparation methods for cationized cellulose derivatives: (1) Williamson etherification, (2) glycidyl route (GTAC), (3) Mannich routes, (4) C6 activation, (5) Michael route, and (6) grafting methods. Table 2. Some homogenous system reaction routes. Reaction route

Utilized for pulps

Cellulose betainate

Borregaard, Domsjรถ, Bahia

Cationization of cellulose acrylate with 3-methylimidazolium propionate chloride

Borregaard, Domsjรถ

Cationization of cellulose acrylate with diethylamine

Borregaard

Cationization of cellulose 2-methylpropanoyl bromide with 1-methylimidazole

Borregaard

Cationization of low DS nitrocellulose

Borregaard

Mannich reactions with cellulose carbamate

Domsjรถ

Cellulose esterification with aromatic, tertiary amine group containing acid halide and its quaternization with methyl iodide

FUBIO CELLULOSE PROGRAMME REPORT

107

Table 3. Used reaction systems for water-soluble derivatives. Abbreviation

Reaction system

Aqueous system with cosolvent (typically 10-50% cosolvent) and 5-8 wt-% of cellulose (heterogeneous). With GTAC.

Biocelsol

5.5% NaOH/1.3% ZnO (homogeneous), 5-8 wt-% of cellulose. With GTAC.

DMAc/LiCl

System with 5% lithium chloride in dimethylacetamide. Typically 1-5 wt-% of cellulose depending on the cellulose type was dissolved in DMAc/LiCl yielding a homogeneous solution. With GTAC.

HC DIT

High-consistency DIT or other reactor system typically with 20-70 wt-% of cellulose (heterogeneous) without any cosolvents. With GTAC.

two-phase

E.g. water-toluene (heterogeneous) with 2-15 wt-% of cellulose. With GTAC.

MIPCl

Cationization of cellulose acrylate with 3-methylimidazolium propionate chloride

NClB

Cellulose betainate (N-chloro-betainate)

Other UH

The other routes studied.

4.3.2 Reaction efficiency of the GTAC routes

Reaction efficiencies were calculated from

There is a clear correlation between high DS

reacted GTAC amount, and they were evaluated

and good reaction efficiency. It seems, however,

for different GTAC routes. The results are shown

that with the reaction systems used it is difficult

in Figure 2, where the calculated reaction

to reach over 50% reaction efficiency. If a large

efficiencies are plotted against the DS achieved.

amount of GTAC reactant is lost, which is the

The plot forms three straight lines when the

case when the reaction efficiency is below

dominating factor is the used GTAC amount.

50%, the manufacturing costs are high, making

This is seen in Figure 3, where the parameter

GTAC cationization uneconomical. Thus, means

â&#x20AC;&#x2DC;Reaction efficiency per DSâ&#x20AC;&#x2122; is plotted against

of achieving a higher GTAC utilization rate need

the used GTAC amount. The best reaction

to be studied further.

efficiencies were obtained with the HC DIT route, thus in high consistency systems. When the best reaction efficiencies from Figure 2 are plotted against the achieved DS, the relationship between achievable reaction efficiency and DS is obtained (Figure 4).

108

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Reac%on eﬃciency (RE), %

50 40 Aq Biocelsol

DMAc/LiCl HC DIT

two-‐phase

10 a)

0,0

0,5

1,0 DS

1,5

2,0

Borregaard Domsjö

Reac%on eﬃciency (RE), %

DAc DENz

Dext SWNDHP

HWNDHP SWND Enoalfa

Ac-‐SWNDHP MeC

10 b)

B-‐SWNDHP MCC 0,0

0,5

1,0 DS

1,5

2,0

Figure 2. Reaction efficiency calculated from reacted GTAC against achieved DS. Classified by reaction system (a) and cellulose type (b).

FUBIO CELLULOSE PROGRAMME REPORT

109

Reac%on eﬃciency RE per DS achieved

140 120 100 Aq

Biocelsol 60

DMAc/LiCl HC DIT

two-‐phase

20 0

0,0

1,0

2,0 3,0 4,0 GTAC used, mol/AGU

5,0

6,0

Figure 3. Parameter ‘Reaction efficiency per DS’ against used GTAC amount.

Max reac(on eﬃciency (RE) based on GTAC, %

0,9

1,1

1,2

1,3

1,4 1,5 DS achieved

1,6

1,7

1,8

1,9

Figure 4. The best achieved reaction efficiencies against the DS values achieved (based on maximum points from Figure 2).

110

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4.3.3 Sample characterization

measured at lower pH was mostly used in the

For flocculating polymers, the key parameters are:

evaluations because the ester derivatives did not give reliable results due to decomposition

• Solubility

by hydrolysis at higher pH.

• Molecular weight (chain length) • Charge density

In the results, samples are classified based on both the reaction route used and the cellulose

The solubility of the cationic cellulose derivatives

starting material.

was characterized by measuring the turbidity of a 1% polymer solution. The effect of polymer

Figure 5 shows the relationship between

chain length was characterized by measuring

measured DS and measured charge density

the viscosity of a 2% polymer solution.

at pH 4. The charge density of most of the

Because the polyelectrolyte charge affects

derivatives is lower than expected based on the

the solution viscosity, salt viscosity was used

DS values. In some cases the charge density

as the main parameter to describe the effect

is, however, higher than expected, especially

of molecular weight. The charge density of the

with some of the DMAc/LiCl samples. The DS

polymer was characterized by polyelectrolyte

of the samples was measured partly based on

titration at pH's 4 and 7.5. The charge density

sample nitrogen content and partly by using

5,0 4,5 Charge density at pH 4, meq/g

4,0 Aq

3,5

Biocelsol

3,0

DMAc/LiCl HC DIT

2,5

two-‐phase

2,0

MIPCl

1,5

NClB

1,0

Other UH theoreEcal

0,5

0,0

0,5

1,0 DS

1,5

2,0

5,0

Borregaard

4,5

Domsjö DAc

3,5

DENz

Charge density at pH 4, meq/g

4,0

Dext

3,0

SWNDHP

2,5

HWNDHP

2,0

SWND Enoalfa

1,5

Ac-‐SWNDHP

1,0

MeC

0,5

Bahia

0,0

theoreHcal 0,0

0,5

1,0 DS

1,5

2,0

Figure 5. Charge density at pH 4 against DS. Classified by reaction system (a) and by cellulose type (b).

FUBIO CELLULOSE PROGRAMME REPORT

111

NMR. Further investigation is clearly required

compared to the majority of the samples. The

in order to clarify the relationship between DS

highest charge densities were achieved using

and charge density.

the DMAc/LiCl reaction system and Domsjö or extruded Domsjö (Dext) pulps.

The solubility behaviour of the samples is presented in Figure 6. Polymer solubility

The highest viscosities were achieved using

improves and thus solution turbidity decreases

cellulose

with increasing charge density. There is no

propionate chloride (MIPCl), HC DIT or DMAc/

exact definition of good solubility, but, for

LiCl reaction routes, and Borregaard pulp,

example,

with

SWNDHP or Domsjö pulp (Figure 7). When the

turbidity lower than 100 NTU, a charge density

salt viscosity correlating with polymer chain

of 2 meq/g of polymer or higher is required.

length is plotted against its charge density in

No significant difference between the reaction

the area of proper solubility (charge density

systems or cellulose types is found, although

>2 meq/g), the figure reveals a clear trend of

the HC DIT reaction system seems to give

reducing viscosity with higher charge density

somewhat lower and cellulose betainate

(Figure 7). This indicates that a very high

(NClB) and 3-methylimidazolium propionate

molecular weight product with very high charge

chloride (MIPCl) somewhat higher solubility

density cannot be obtained.

when

targeting

solutions

betainate,

3-methylimidazolium

Turbidity at 1 %, NTU

10000

1000

Aq DMAc/LiCl HC DIT

100

two-‐phase MIPCl NClB Other UH

0,0

0,5

1,0

1,5 2,0 2,5 3,0 3,5 Charge density at pH 4, meq/g

4,0

4,5

5,0

10000

Turbidity at 1 %, NTU

Borregaard Domsjö

1000

DAc Dext SWNDHP HWNDHP

100

SWND Enoalfa Ac-‐SWNDHP

MeC Bahia

0,0

0,5

1,0

1,5 2,0 2,5 3,0 3,5 Charge density at pH 4, meq/g

4,0

4,5

5,0

Figure 6. Turbidity against charge density at pH 4. Classified by reaction system (a) and by cellulose type (b).

112

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Salt viscosity at 2 %, mPas

10000

1000

Aq Biocelsol DMAc/LiCl HC DIT

100

two-‐phase MIPCl NClB

Other UH

a) 1

2,0

2,5

3,0 3,5 Charge density at pH 4, meq/g

4,0

4,5

10000 Borregaard

Salt viscosity at 2 %, mPas

Domsjö DAc

1000

DENz Dext SWNDHP

100

HWNDHP SWND Enoalfa Ac-‐SWNDHP

MeC Bahia

2,0

2,5

3,0 3,5 Charge density at pH 4, meq/g

4,0

4,5

Figure 7. Salt viscosity vs. charge density, when charge density is >2 meq/g. Classified by reaction system (a) and by cellulose type (b).

4.4 Cationic particles Two main cationization routes were used to

scale particles was the product suspension

produce cationic nano-scale particles, see

concentration, which remained <0.5% after

Table 4.

the comminution stage in a high intensity homogenizer.

Cationization was tested both before and after cellulose comminution. Comminution after

Concentration of the suspension was also

cellulose cationization was considered to be

tested, and promising results were obtained by

better. In addition, commercial microfibrillated

concentrating the suspension to 30-100% with

and nanofibrillated celluloses were tested in

no significant loss in performance efficiency. It

cationization.

was also found that drying without performance loss can be achieved if the particles have a

The main problem with the cationic nano-

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higher charge density.

113

Table 4. Cationic particle reaction systems and achieved charge densities. Abbreviation

Reaction system

Maximum charge density achieved at pH 4, meq/g

AminoG

Periodate oxidation of cellulose to dialdehyde cellulose and subsequent cationization using aminoguanidine

2.3

hydrochloride Girard’s T

Periodate oxidation of cellulose to dialdehyde cellulose and subsequent

1.2

cationization using Girard’s reagent T

4.5 Performance evaluation

route, perform better in sludge dewatering than expected based on their charge density.

Product performance was evaluated using

On the other hand, the HC DIT made samples

laboratory-scale methods. Sludge dewatering

seem to perform worse than expected based on

was tested using a CST (capillary suction time)

their charge density. One possible explanation

method where the speed of water drainage

for this is that because the HC DIT route is a

from a sludge into a standardized piece of board

heterogeneous system, the charge created

is measured; the shorter the drainage time, the

during the modification is not evenly distributed.

better the dewatering capacity. Flocculation

In addition, pulp type was found to have less

efficiency, describing, for example, retention on

of an impact on performance than expected;

the paper machine, was tested using the FBRM

the Dext and Domsjö pulps were among the

(focused

measurement)

best performers with the DMAc/LiCl route, but

method, which detects the particle or floc

well-performing samples were also made using

size of the suspension dynamically, with shear

Borregaard pulp.

beam

reflectance

forces induced in the suspension controlled by mixing speed and time of mixing; the bigger floc

None of the cellulose derivatives had as good

size, the better the flocculation efficiency. Pitch

performance in CST as the reference polyacryl-

control by fixing was tested by measuring how

amide, although their performance was not

much turbidity in a mechanical pulp suspension

far from the reference (Figure 8). There are

water is removed by adding the fixing agent;

indications that sludge dewatering performance

the higher the removal percentage, the better

of the derivatives improves with higher molecular

the fixing performance.

weight, but this requires further confirmation.

The relationship between CST time and charge

Typical FBRM curves are presented in Figure

density of the sample is shown in Figure 8,

9. When a flocculant is dosed, the floc size

which clearly reveals charge density to be the

increases rapidly. When shearing is induced,

dominating factor in CST performance. The

i.e. mixing is continued, the floc size starts to

best performing samples are those with the

decrease. With some cellulose derivatives it was

highest charge density.

found that even though the initial floc size was not as big as the reference, the decrease in floc

114

Some additional conclusions can also be drawn.

size due to shearing was not as severe as the

Certain products, such as the cationic nano-

reference. Moreover, after a certain shearing

scale particles and derivatives made via the

level the floc size of the cellulose derivative was

methylimidazolium propionate chloride (MIPCl)

larger than with the reference (Figure 9).

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260 240 220

200

Biocelsol

CST %me at 8 kg/t, s

180

DMAc/LiCl

160

HC DIT

140

two-‐phase

120

MIPCl

100

NClB

Other UH

AminoG

Girard's T

20 0

0,0

0,5

1,0

1,5 2,0 2,5 3,0 3,5 Charge density at pH 4, meq/g

4,0

4,5

5,0

260

Borregaard

240

Domsjö

220

DAc

200

DENz

CST %me at 8 kg/t, s

180

Dext

160 140

SWNDHP

120

HWNDHP

100

SWND

Enoalfa

Ac-‐SWNDHP

Bahia

20 b)

0,0

0,5

1,0

1,5 2,0 2,5 3,0 3,5 Charge density at pH 4, meq/g

4,0

4,5

5,0

Birch (Kaskinen) MFC

Figure 8. CST times vs. charge density at 8 kg/t dosage. Classified by reaction system (a) and by cellulose type (b). Reference polyacrylamide, Fennopol K506, gave a typical CST time of <10 s at 6-8 kg/t dosage. The sludge is a municipal digested sludge, pH 7-7.5 (all CST tests). Tests were performed at different times using different sludges from the same source.

FUBIO CELLULOSE PROGRAMME REPORT

115

Mean ﬂoc size, µm

50 45

Fennopol K3400R_4kg/t

UH-‐FBC-‐WP4-‐I_12kg/t

UH-‐FBC-‐WP4-‐I_8kg/t

UH-‐FBC-‐WP4-‐I 4 kg/t

25 20 15 10

15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Mixing 1me, s

Figure 9. Curves measured using the FBRM method. Fennopol K3400R is the polyacrylamide reference. UH-FBC-WP4-I is a sample made from Borregaard pulp using the cellulose betainate route. Dosing as kg active / t dry. See other details in Figure 10.

The dependence of flocculating efficiency on

increasing with higher shear levels. In high

salt viscosity remains an anomaly, see Figure 10.

shearing systems the cationic particle thus

In some cases high salt viscosity of the product

gave as good, or even better, final flocculation

clearly gave better flocculation efficiency. This

efficiency than the reference polyacrylamide.

was the case for samples made using cellulose betainate (NClB), MIPCl or HC DIT reaction

The fixing performance of selected samples

systems and mostly Borregaard, SWNDHP or

is presented in Figure 12. While some samples

Enoalfa pulps. However, the same pulps also

performed better than the reference, worse

resulted in samples that did not show good

performance was found in many cases. The

flocculating efficiency despite having high salt

cationic nano-scale particles performed clearly

viscosity. The reason for this odd behaviour is

worse in fixing than many other samples.

still unclear.

Some properties of the samples used in the

fixing tests are presented in Table 5. The best

The

performed

performing samples in the fixing tests clearly

well in the flocculation tests. The better

cationic

particles

also

belong to the group with the highest charge

performing cationic particle, made using the

densities. Interestingly, the fixing performance

aminoguanidine route, gave a maximum mean

of many of the cellulose derivatives with a

floc size of 24-27 µm at 12 kg/t dosage.

clearly lower charge density than the reference was comparable or better than that of the

The cationic particles had an odd effect on floc

polyamine reference having a charge density of

strength, see Figure 11. Floc size increase was

about 7 meq/g.

minimal, but shear resistance was high, even

116

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Max mean ﬂoc size at 12 kg/t, µm

Aq Biocelsol DMAc/LiCl

HC DIT two-‐phase MIPCl

NClB Other UH

100 1000 Salt viscosity at 2 %, mPas

10000

Max mean ﬂoc size at 12 kg/t, µm

Borregaard

Domsjö

DAc DENz Dext

SWNDHP HWNDHP SWND

Enoalfa Ac-‐SWNDHP Bahia

100 1000 Salt viscosity at 2 %, mPas

10000

Figure 10. Maximum mean floc sizes at dosing 12 kg/t from the FBRM experiments against salt viscosity. Classified by reaction system (a) and by cellulose type (b). Tests were made at different times using the same type of mechanical pulp from two different sources. Furnish suspension: 60% groundwood, 40% PCC, pH 7.5, mixing speed 1500 rpm (all FBRM tests).

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117

50 Fennopol K3400R 4 kg/t

45 40

Mean ﬂoc size, µm

AGDAC11_4 kg/t

AGDAC11_17 kg/t

30 25 20 15 10

15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Mixing 1me, s

Figure 11. Curves measured using the FBRM method. Fennopol K3400R is the polyacrylamide reference. AGDAC11 is a cationic nano-scale particle sample.

100

Turbidity removal (%)

VTT-‐312

Groundwood pulp

VTT-‐311

80 70

UH-‐FBC-‐ WP4-‐VII UH-‐1-‐1

Polyamine

VTT-‐313

VTT-‐320

UH-‐FBC-‐ WP4-‐VI AGDAC11

20 600

800

1000

1200 1400 Dosing, g/t

1600

1800

2000

Figure 12. Fixing performance of selected samples. Groundwood pulp, pH 6.9. Dosing as g active / t dry pulp. Polyamine is the reference polymer.

118

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Table 5. Some properties of the samples mentioned in the figures above. Nd=not determined.

Code

Cellulose

Reaction system

AGDAC11

Birch (Kaskinen)

Aminoguanidine

UH-1-1

Viscosity 2%, Salt viscosity Turbidity 1% mPas 2%, mPas (NTU) nd

Charge pH 4 meq/g

2.3

Domsjö

NClB

394

1.9

Borregaard

NClB

55000

4515

2.6

UH-FBC-WP4-VI

Domsjö

MIPCl

3.5

UH-FBC-WP4-VII

Bahia

NClB

3.6

VTT-311

Dext

DMAc/LiCl, GTAC

4.4

VTT-312

Dext

DMAc/LiCl, GTAC

4.3

VTT-313

Dext

DMAc/LiCl, GTAC

3.1

VTT-320

Domsjö

DMAc/LiCl, GTAC

4.5

UH-FBC-WP4-I

4.6 Summary of the results • The best pulp activation method found was wet disintegration. Chemical pre-treatment or freezing did not increase pulp reactivity. Use of microwaves during the activation and reaction stages gave better results than conventional heating. • The best reaction routes identified for cationization were GTAC synthesis, the

• Sludge dewatering performance (CST): - Prefers high charge density, except with cationic particles - Best reaction systems: MIPCl and other Michael routes, NClB and cationic particles - Best starting celluloses: no significant differences, only SWNDHP gave poorer results

cellulose betainate route, and cationic

• Flocculation performance (FBRM):

particles. All three routes have their benefits

- Prefers high molecular weight, except

and limitations, but none of them alone result in sufficient cationization. • High-consistency reaction systems were the best systems identified. • Good solubility of a cationic cellulose derivative requires a charge density of about 2 meq/g (DS about 0.5). • When the charge density of the cationic end product is higher, the molecular weight tends to be lower. • Different applications require different polymer properties.

with cationic particles where cellulose DP is irrelevant - Best reaction systems: NClB, HC DIT, MIPCl and other Michael routes, cationic particles - Best starting celluloses: Borregaard, SWNDHP and Enoalfa - Cellulose derivatives did not give as big floc size as the reference polyacrylamide, but flocs were more shear resistant • In pitch control by fixing, some derivatives performed better than the reference. • Normal kraft pulp can be used, hemicelluloses have no significant effect on performance.

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119

4.7 Markets and business opportunities for cationic water-soluble cellulose

Demand for cationic water-soluble cellulose in water treatment applications is driven by limited water availability, changes in water

About 20% of water-soluble polymers bear a

use, increasing quality requirements, types

cationic charge, while the remaining 80% consist

of pollutants, trade-offs between various

of anionic and neutral polymers. Key properties

chemical compounds, government policies,

of cationic polymers are molecular weight

and the emerging bio-based economy. Water

and charge density, which vary significantly

scarcity is the key driver behind all water-

depending on the end-use application. The

related businesses and has driven both public

cationic cellulose developed in the FuBio

and private sectors to focus on water recycling,

Cellulose programme has a molecular weight

reutilization and minimization of discharge

and charge density suitable for coagulation

water â&#x20AC;&#x201C; all of which increase the demand for

and flocculation applications. The key end-use

water treatment chemicals.

sectors for cationic cellulose therefore include the water treatment, pulp and paper, oil, mining,

Geographical location, seasons, and water

cosmetics and textile industries.

end-use have a major impact on the type and amount of coagulants and flocculants required.

The most widely used cationic polymer is

Demand for cationic polymers, in particular,

polyacrylamide (PAM), followed by quaternary

is growing alongside increasing energy and

ammonium polymers and polyamines. Less

resource efficiency targets. Municipal and

than 10% of cationic polymers are currently

many industrial wastewaters bearing impurities

based on natural materials such as chitosan.

with high anionic charge can be effectively

Large-scale

neutralized

manufacturers

bio-based

with

cationic

flocculants.

The

cationic chemicals are currently few in number,

required molecular weight and charge density

but there is significant research interest in this

of the applied cationic polymer depends on the

area. Because the FuBio Cellulose products

types of pollutants contained in the wastewater.

were developed specifically as coagulants

Selecting the optimum coagulant and flocculant

and flocculants, other potential water-soluble

combination includes trade-offs among various

polymers, such as cationic starch, were

chemicals. For instance, the ratio of metal salts

excluded from the market analysis.

to cationic polymers, or the ratio between different cationics may be altered based on

Water treatment and pulp and paper are the

chemical price changes to optimize overall

largest

together

cost efficiency. In most applications, the right

account for over 80% of annual cationic

coagulant and flocculant combination needs to

polymer consumption. Key applications in these

be confirmed by on-site sedimentation tests.

end-use

markets,

which

sectors include coagulation and flocculation in

120

raw water and wastewater treatment, sludge

Government

dewatering, and retention aid in pulp and

influence on the demand development of

policies

also

have

strong

paper processes. Different applications require

cationic polymers. Dosage volumes depend

different polymer properties. For example,

on the required purity levels (e.g. COD, BOD5

sludge dewatering requires a high molecular

and phosphorus), which vary in different

weight with linear, branched or cross-linked

administrative regions. There are planned

structures, whereas coagulant polymers have

legislative restrictions for cationic polymers in

much lower molecular weight but very high

Spain, Germany and Sweden driven by monomer

cationic charge.

residues, biodegradability and sustainability,

FUBIO CELLULOSE PROGRAMME REPORT

respectively. These restrictions would limit or

cosmetics is short and polymer quantities small.

even ban the use of the most common cationic

Cosmetic applications do not require very high

polymer, c-PAM, and thus, could open new

molecular weight or high cationic charge, and

opportunities for cationic cellulose. In addition,

therefore the technical substitution potential of

any actions supporting the creation of a bio-

cationic cellulose is very high.

based economy will support the adoption of alternative bio-based materials.

The pulp and paper industry was also an interesting end-use for cationic cellulose. Pulp

In order to identify the potential of cationic

and paper production is the second largest

cellulose in different end-use sectors, a variety

market for cationic chemicals in general. Both

of factors were analysed, including market

the end-use market and the use of cationic

size, growth of the end-use segment, growth

chemicals

of cationic chemical use in that segment, unit

mostly in emerging markets. The key factors

value, and capability and willingness to pay

determining the potential of cationic cellulose

for bio-based or biodegradable products.

in cosmetics and pulp and paper applications

However, the most crucial factors affecting

are summarized in Figure 13.

are

slightly

growing,

although

the potential for cationic cellulose were the technical substitution potential, unit value and regulatory environment. According

the

cosmetic

The techno-economic analysis examined the

applications seemed the most promising end-

production of cationic water-soluble cellulose

use for cellulose-based cationic chemicals.

production for water purification applications.

Although the market size of cationic chemicals

The process concept of carboxymethylcellulose

in cosmetics is small, both the cosmetic

(CMC) was used as a general reference for the

industry and the cationic chemicals used in

cationic cellulose process concept. Five different

hair care products (mainly polyquaternium) are

process variations were evaluated: (i) aqueous

estimated to grow at a respectable rate of over

media with GTAC as reagent, (ii) organic media

3% per annum. There is a clear demand for

with GTAC as reagent, (iii) reactive dissolving

bio-based raw materials in cosmetic products

with chloro-betainyl chloride as reagent, (iv)

and the industry has both the capability and

DMAc-LiCl as organic media and (v) a high-

willingness to pay a premium for specific

consistency process. Figure 14 shows a block-

products. However, the product cycle in

flow diagram of the studied process concept.

Cosmetics

analysis,

4.8 Techno-economic modelling of cationic cellulose

Technical substitution potential

Growth potential of the end‐use segment

Threat of subsitution chemicals

Growth potential

Threat of new technologies Legislative environment of the end‐use segment Pöyry Management Consulting Oy

Pulp & Paper

Market size

Unit value

Regulative restrictions

Capability and willingness to pay

Market size

Technical substitution potential

Growth potential of the end‐use segment

Threat of subsitution chemicals

Growth potential

Threat of new technologies Legislative environment of the end‐use segment

Unit value

Regulative restrictions

Capability and willingness to pay

Figure 13. Potential of cationic cellulose in cosmetics and pulp and paper applications.

FUBIO CELLULOSE PROGRAMME REPORT

121

Cellulose

water-soluble cellulose in water treatment

NaOH water

applications are summarized in a SWOT analysis in Figure 15.

Basification

DMAc LiCi

GTAC

Cationization

HCI

Neutralization

5. Exploitation plan and impact of the results Use of cellulose pulp as a raw material for the production of cationic flocculants was

Filtration

shown to have good potential for industrial utilization. The ready availability of cellulose,

Solvent recovery

as the largest annually renewable biomass on

Washing IPA

the planet, further underscores the potential of this raw material.

Drying

Cellulose derivatives are normally produced using a dissolving pulp. The present study,

Cationic cellulose

however, showed that normal kraft pulp can be

Figure 14. Block-flow diagram of cationic watersoluble cellulose production.

used irrespective of hemicellulose removal; only

Based on the techno-economic analyses,

was observed when hemicelluloses were not

the high-consistency process seems to be

removed. This is a key finding, as it affects the

the most promising of the five concepts. The

raw material price remarkably.

a minimal impact on final product performance

cationic derivatization agent GTAC was the biggest production cost factor and thus had

A major impact on end product properties was

a major impact on the economic feasibility.

found if the starting cellulose raw material

As a result, further research should focus

was not heat dried before use. This calls for

on reducing GTAC consumption either by

integrating cationic derivatization of cellulose

increasing reaction efficiency or by improving

close to pulp manufacturing. Although never-

chemical recovery and recycling.

dried pulp performed better, normal heatdried pulp can also be used.

Cationic water-soluble polymers are performance chemicals, and their performance thus defines

The preferred pulp is softwood. Hardwood pulp

their potential selling price. Product functionality

gives a higher molecular weight end product, but

and application testing should be a top priority

reacts less readily. The hemicellulose content of

of future research and product development.

hardwood is also higher than that of softwood.

Monomer

residues,

biodegradability

and

sustainability are the key driving forces

Although the majority of the present findings

behind planned legislative restrictions on

require further confirmation, the results at this

cationic polymers in Spain, Germany and

stage are very promising.

Sweden, respectively. Product development should

122

these

Several potential reaction types could be

unique opportunities for cationic cellulose.

also

focus

exploiting

developed, although none of them can be

The strengths and weaknesses of cationic

utilized directly.

FUBIO CELLULOSE PROGRAMME REPORT

Process related

Helpful to achieving business success

STRENGTHS

WEAKNESSES

• Growing demand for both bio-based water

• Reagent represents too high share of total

treatment chemicals and for cationic

production costs.

polymers as a whole

• DIT reactor can operate at high consistency

• Legislation may support development of bio-based cationic chemicals

but processing high viscosity material streams may be challenging.

• Economic feasibility seems attainable

• Expensive and harmful reagent needed with a risk of harmful residues

Business environment related

OPPORTUNITIES

THREATS

• Bio-based replacement for c-PAM

• Product quality cannot reach c-PAM

• New end-use for dissolved cellulose

• Full sustainability assessment (cradle-

• New business opportunities for FIBIC

to-grave) may not show significant

• CMC production is already existing, same analogy could be used here

improvements to c-PAM • Bio-based monomer development

• Potential biodegradability

Figure 15. SWOT analysis of cationic water-soluble cellulose.

GTAC

synthesis

lacks

reaction

efficiency,

cellulose

betainate

product,

namely

the

which increases reactant consumption and

stability of the dry product and, because they

thus manufacturing costs. The best reaction

are esters, the need for special attention in the

efficiency

application systems. Thus, further development

achieved

was

55%,

and

any

significant further increase on this is considered

of cellulose betainate is also required.

unlikely. One means of making the GTAC route more viable is to find a way to regenerate and

The third promising technique found is the use

circulate the extra reactant. This offers a very

of nano-sized cationic particles. The particles

interesting avenue for further research.

performed comparably to soluble polymers and, in some cases, even better. However, the

The GTAC synthesis results show how important

studied route has two weak aspects. One is

the processing consistency or concentration is

cationization through the aldehyde oxidation

during the reaction. The more solvents or other

route, which presents a challenge regarding

media that are needed, the higher the recycling

chemical recycling. Another weak point is the

costs. Low processing concentration is the

product concentration. After the comminution

weakest link in the cellulose betainate route

stage the product concentration is below 0.5%.

developed. The end product properties were

Good progress was made in the concentrating

good, but the processing cost became high due

studies, but the drying method used, freeze

to too low concentration during processing.

drying, is technically undesirable. While simple

The process economics would be dramatically

thermal drying is not effective, methods such

improved if the processing could be done in

as fluid bed drying or spray drying deserve

a high concentration system, such as in an

further study. Due to the large amounts of

extruder, kneader or such. This requires further

water removed, the drying technique used

study, with a focus on high viscous processing.

must be combined with mechanical dewatering

Uncertainties also remained regarding the

in order to become economically feasible.

FUBIO CELLULOSE PROGRAMME REPORT

123

Thus although none of the processes is ready

Flocculating applications that do not require very

as such, there are several options for further

high charge densities may be more attractive in

development, either each route separately or by

the first instance, as the reaction efficiency with

combining the best parts from each one. Other

these was the highest. However, this depends

interesting reaction routes, which remained

heavily on the chosen reaction route.

outside the scope of the present study, should also be examined. In addition, the Michael type

Efficient raw material utilization and low-cost

addition reactions, to which the MIPCl route

and low-toxic reactants are the key issues in

also belongs, gave very interesting and well-

the successful cationization of cellulose. The

performing samples, although more work is

ultimate solution for producing cationic cellulose

required to find a substitute for trifluoroacetic

may be based on one of these processes, or

acid used in it.

be a combination of several of them. The final success of cellulose cationization will depend

Although the derivatives did not generally

not only on process efficiency, but also on how

perform as well as the reference polyacrylamide,

raw material prices develop compared to the

their performance matched the reference

raw material prices of synthetic polymers.

when combined with polyacrylamides. In some applications, such as high shear condition flocculation and pitch control by fixing, some of

6. Networking

them performed even better than the reference products.

The research was carried out jointly and exclusively by the programme partners, see Table 7.

Table 7. Partner organizations and their roles.

124

Partner

Role

Glocell

Qvantitative economic modelling.

Kemira

Steering of overall work. Sample characterization and application testing. Defining, steering and providing competence for the modelling. Providing industrial insight to techno-economic assessments.

Metsä Fibre

Industrial tutor. Providing industrial insight to techno-economic assessments.

Pöyry Management Consulting

Market study. Economic feasibility modelling. Business potential evaluation.

Stora Enso

Industrial tutor. Providing industrial insight to techno-economic assessments.

University of Helsinki • Organic Chemistry

Synthesis development of water-soluble polymers. New routes.

University of Oulu • Fibre and Particle Engineering

Synthesis development of cationic particles.

UPM-Kymmene

Industrial tutor. Providing industrial insight to techno-economic assessments.

VTT

Synthesis development of water-soluble polymers. GTAC routes. Techno-economic modelling.

FUBIO CELLULOSE PROGRAMME REPORT

7. Publications and reports Publications

Kavakka,

J.,

Sievänen,

K.,

Labaf,

S.,

Lagerblom, L., Kilpeläinen, I., Karisalmi, K. Liimatainen, H, Suopajärvi, T, Sirviö, JA,

and Ahlgren, J. Towards Cationic Cellulose:

Hormi, O. and Niinimäki, J. Fabrication of

Reactive Dissolution Approach. FuBio Seminar,

Cationic Cellulosic Nanofibrils through Aqueous

Espoo, June 12, 2012.

Quaternization Pretreatment and Their Use in Colloid Aggregation. Carbohydrate Polymers

Kavakka, J., Sievänen, K., Labaf, S., Lagerblom,

103, 2014:187-192.

L., and Kilpeläinen, I. Cellulose:

Reaction

Towards

Dissolution

Cationic Approach.

Presentations

FuBio Seminar, Espoo, October 1, 2012.

Ahlgren, J., Jääskeläinen, H., Kurkinen, S.,

Liimatainen H, Sirviö J, Niinimäki J and Hormi

Rouhiainen, J., Salmenkivi, K., and Hult Mori,

O. Cationic cellulose particles as flocculation

E-L. New products: The market potential for

agents. FuBio Programme Seminar, Espoo, June

cationic cellulose chemicals. FuBio Cellulose

12th, 2012.

Seminar, Espoo, June 12, 2012. Sievänen, K., Kavakka, J., Fiskari, J., Vainio, P., Ahlgren, J. Cationic chemicals. FuBio Seminar,

Karisalmi, K. and Kilpeläinen, I. 2013. Synthesis

Espoo, October 1, 2012.

of Cationic Cellulose derivative for Wastewater Treatment. FuBio Programme seminar, Espoo,

Posters

August 27, 2013.

Karisalmi, K. and Kyllönen, L. Activation

Vuoti,

studies

2013. Cellulose cationization in water. FuBio

cellulose

derivatization.

seminar, Espoo, August 27, 2013.

FuBio

S.,

Setälä,

and

Karisalmi,

Programme seminar, Espoo, October 22th, 2013.

ABBREVIATIONS Pulp types: see Table 1 Reaction routes: see Table 3 • • • • • • • •

CMC = carboxymethyl cellulose CST = capillary suction time; a sludge dewatering testing method DP = degree of polymerization; corresponds to molecular weight DS = degree of substitution; corresponds to charge density FBRM = focused beam reflectance measurement; a dynamic floc size measuring method GTAC = glycidyltrimethylammonium chloride; a cationization reagent NMR = nuclear magnetic resonance spectroscopy PCC = precipitated calcium carbonate

FUBIO CELLULOSE PROGRAMME REPORT

125

The FuBio Cellulose programme focuses on promoting selected novel value chains starting from wood derived cellulose. The specific target of the programme is to develop novel sustainable processes for production of staple fibres, new cellulose based materials and water treatment chemicals. The programme provides knowledge and capabilities supporting the new value chains based on wood cellulose products.