Processing, Chemistry and Applications of LAC by Kisan Forum Pvt. Ltd.

Processing, Chemistry and Applications of Lac

Technical Editors

Bangali Baboo National Director, NAIP, ICAR Krishi Anusandhan Bhavan I, New Delhi 110 012

D N Goswami Ex-Principal Scientist, Indian Institute of Natural Resins and Gums Namkum, Ranchi, Jharkhand 834 010

ICAR

Pubished by Directorate of Information and Publications of Agriculture Indian Council of Agricultural Research New Delhi 110 012 www.icar.org.in

Printed

Project Director

Incharge (English Editorial Unit) Editing

Chief Production Officer Technical Officer (Production)

July 2010

Dr T P Trivedi

Dr R P Sharma Dr Sudhir Pradhan V K Bharti Punit Bhasin

ISBN : 978-81-7164-065-2

Price: Rs 200

Publishedby Dr T P Trivedi, Project Director, Directorate ofInformation andPublications of Agriculture, Indian Council of Agricultural Research, Krishi Anusandhan Bhavan I, Pusa, New Delhi 110 012 Telephone: 011-25842787, Fax: 011-25843285, E-mail: tptrivedi@icar.org.in; Lasertypeset by M/s Xpedite Computer Systems, D-20, 2nd Floor, Ranjit Nagar Commercial Complex, New Delhi 110 008 and printed at M/s Chandu Press, D-97, Shakarpur, Delhi 110 092

Contents Foreword

Preface

iii iv

Lac: an introduction B Baboo and D N Goswami

Processing of lac D N Goswami and P C Sarkar

Chemistry of lac resins and its constituent acids Niranjan Prasad

Chemistiy of lac dye and wax S Srivastava, MF Ansari and DN Goswami

Physical properties of lac D N Goswami

Spectral properties of lac S Srivastava, MF Ansari and D N Goswami

Electrical properties of lac

D N Goswami

Applications of lac D N Goswami and P C Sarkar

118

Shellac versus synthetic resin: the advantages and disadvantages Bangali Baboo, D N Goswami and S Srivastava

154

10.

Quality evaluation, standard specification of lac and lac products NPrasad, D Ghosh and K MSinha

159

11.

Future scope of use of shellac DN Goswami and B Baboo

177

Subject Index

183

1 Lac: an introduction B

Baboo1 and D N Goswami2

Indian Institute of Natural Resins and Gums Ranchi (Jharkhand) 834 010

T AC is derived from the Sanskrit word “lakh” which means 100,000 J—/and refers to the vast swarms of insect larvae that cover twigs of host trees during brood season. Lac is a general term used in the trade for all forms of natural resin, which is secreted by the tiny lac insects on certain host trees, principally found in India, Thailand, China and Indonesia. Lac history can be traced back to Vedic period (C.1500 to 500 B C). Atharva Veda devotes a chapter containing vivid description of ‘Laksha\lac insect) and its use in invigorating potion and wound healing. In the great epic, Mahabharata, Purochak constructed ‘Lakshagriha ’ (house of lac) at the instance of Kauravas for killing Pandavas. The works of a number of foreign travellers reveal the trade of lac from India to a number of countries during post-Vedic and medieval periods. Use of lac is known in India for centuries especially as the source of dye and decorative coatings. Records from the late 1500’s reveal its use for decorating public buildings duringMoghul ruler Akbar (Martin, 1982). Its use in China is reported, for application molten waxes to oranges and lemons, as early as 12th or 13th century. It was also known to ancient Greek and Roman writers and widely used in Europe for furniture finishing during late fifteenth century (Class, 1991). The superb adhesive quality of the resin made it useful for setting jewels and sword hilts as well as repairing broken pottery. The residue left after extraction of the dye was made into a grinding wheel for jade — the technique is used even today. Shellac (refined commercial form of lac resin) and different shellacbased products began to make their way into European commerce and industry after historical journey of Marco Polo to Orient in late 13th century. Detailed description about the cultivation, harvesting, processing and use of lac is available in the literature as early as 1534. Painters started use of shellac resin, shellac dye and shellac wax not only to create their masterpieces, but also to provide them with a protective finish by the mid17th century. Shellac became the coating of choice for costly furniture, woodcarvings, and turnings for craftsmen and artisans. Even today some of the finest museum pieces still have their original shellac finish. 'Ex-Director, 2Ex-Principal Scientist.

PROCESSING, CHEMISTRY AND APPLICATIONS OF LAC

COMPOSITION AND APPLICATIONS OF LAC (A natural resin of insect origin with unmatched versataiity) Varnish and printing ink industry

LAC WAX (Mixture of higher alcohols, acids, esters and hydrocarbons)

tellae is m toxic and ivironmenti

Furniture polish (French polish) 4 Floor polish ÂŁ Sealers # Pattern paints for wood 4 Flexible and fast-drying agent for printing ink <1 Heat and water-proof varnishes

U Shoe automobile and flow polishes

4 Bottle sealer ÂŁ Tailor's chalk

LAC DYE (anthrapnone derivative) -# Dyeing of wool and silk

Soft drink formulations Pill coating 4 Sausage finishing 4 Confectionery and chocolate coating 4 Finished food coating 4

Crayons fesp. for writing on glass)

*4 Electrical Lipstick

potting compounds

4 Fruit coating

Lac dye 1%

25%

4 Water-thinned shellac red-

Cosmetic industry

oxide primer and paints Metal lacquers and dry lacquering of wood

Adhesive industry

# Hair spray, lacquer 4 Eyeshadows

d Gasket cement

Lac resin 68%

4 Microencapsulated perfumes 4 Lipstick, nail polish, mascara, etc.

4 Optical cement 4 Sealing wax

LAC RESIN (An ester complex of long chain hydroxy fatly acids and sesqaiferpenic acids)

Electrical industry # Air-drying and baking-type insulating varnishes

4 Grinding wheel 4 Hot-melt adhesive 4 Polymer adhesives Adhesives for si-chips and solar ceils

# Coating of isolators, PCB's, etc.

Food industry

4 Micarates {sheets, tubes and moulded insulators)

4 Coating of fruits

Miscellaneous 4 Diamond and crystal cutting 4 Jewelfary 4 Polishing stone 4 High efficiency igniter-cum-fuei 4 Slow release fertilizer, pesticide, etc. si Proofing and stiffening in hat

4 Coating of chocolates,lozenges, coffee beans 4 Coating of aluminium foils for making pizzas 4 Non-toxic ink of marking food stuff # Internal can coating

4 Cement for sockets of electrical lamps 4 Shellac bond powder 4 Anti-tracking insulating varnish 4 Coating of spark plugs

making

Leather Industry 4 Adhering coating of leather with metallic and plastic foils

4 Top-dressing material

Water-soiubie lac for earthenware 4 Shellac etch primer 4

Lac wax 6% Others

Pharmaceutical industry

\4 Coating of tablets 14

Microencapsulation of vitamins

Iis a renewable" I

1 4 Coating of medicines tor slow[

release/deiayed action

[ 4 Marking ink for capsules, tabs, etc. j

iiource. It can be

as a substitute r synthetic mate? !. several

Fig. 1.1. Composition and aplications of lac

appiicati

LAC: AN INTRODUCTION

Two English brothers had set up a big commercial lac industry in India in 1855 mainly for supply of lac dye. First record of the lac dye export to Europe was, however, in 1607, which flourished up to close of 19th century till the advent of aniline dyes. Subsequently, the lac resin exports picked up particularly for use in gramophone industry, varnishes, etc. The use of lac has now diversified into a wide range of areas (Fig.1.1).

LAC: A PRODUCT OF PLANT AND INSECT INTERACTION Shellac is derived from the hardened secretion of lac insect Kerria spp. feeding on resiniferous trees and bushes cultivated in India, Burma, Thailand, Laos, Cambodia, China and Vietnam. The resin is secreted as a covering for the insect larvae. Even though 87 species of lac insects have been reported world-wide, only a few species are useful for commercial lac production. Lac production Lac was primarily collected from the forests till the end of 19th century and during the beginning of 20th century, its cultivation started due to its varieties of applications and increasing demand. The Indian Lac Research Institute provided a scientific cult to lac cultivation after its establishment in 1924 at Namkum. Lac production in India is contributed by Jharkhand, Chhattisgarh, Madhya Pradesh, West Bengal, Orissa and Maharashtra. Lacgrowing regions are generally dominated by economically resourceconstrained tribal population. The areas comprise high proportions of forest and uncultivable land with poor irrigation facilities and the areas possess low literacy levels, high proportion of scheduled tribes and population below poverty line. Considering available resources, economic and cultural aspects of the inhabitants, lac cultivation is ideally suitable for livelihood enhancement/economic progress in such regions. Lac cultivation has proved to be an important source of cash income in such areas, especially, at the failure of the national agricultural crops. There had been a major drop in lac production in 1998, due to crop failure in Jharkhand because of adverse climate (Fig.1.2). The production has recovered to normal levels in the recent years. Speedy recovery of lac production after failures is constrained by storability and transportation of brood lac over long distances. Therefore, there is a greater need to expand production base to a larger area over different agro-climatic regions of the country and to establish brood lac production farms in different locations to ensure production stability in the country. Interaction with representatives of lac industry indicated a very large unrealized demand for lac in the country and overseas. It is felt that there is an ample scope for aiming a quantum increase in the lac production to realise this untapped potential.

PROCESSING, CHEMISTRY AND APPLICATIONS OF LAC

25000 ®

20000-

15000-

.1 -g

10000 -

5000 0

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Year Fig. 1.2. Production of stick-lac in India

Lac insects and lac hosts

In India, lac cultivation is done mainly through culture of Indian lac insect Kerria lacca on hosts, viz. kusum (Schleichera oleosa),palas (Butea monosperma) and ber (Ziziphus mauritiana). Two lac crops are produced in a year corresponding to two cycles completed by insect in an year. The Indian lac insect has two strains, kusmi and rangeeni, differing in lifecycle pattern, host-plant preference and quality of lac (resin) produced. Kusmi insect is characterized by high productivity and best quality of resin produced in the world. To produce 1 kg of lac resin around 50,000 insects are required (Table 1.1). Table 1.1. Important host trees for lac insects in different lac-producing countries Country

Common host trees

Scientific name

Family

India, Principal hosts

Kusum

Schleichera oleosa (Lour.) oken Butea monosperma (Lam.) Taub. Ziziphus mauritiana Lam. Acacia catechu (L.f.)Willd. A. nilotica (L.) Delile Cajanus cajan (L.) Millsp. Caesalpinea sappan L. Ficus religiosa L. Ficus benghatensis Samanea saman (Jacq.) Merr. Cajanus cajan (L.) Millsp. Dalbergia balencea. Hibiscus spp.

Sapindaceae

Palas/dhak Ber India, other hosts

Khair/cutch Babul Arhar Sappan Pipai Banyan

Thailand, most common China

Rain tree Arhar

Leguminosae

Rhamnaceae Leguminosae Leguminosae Leguminosae Leguminosae Moraceae Moraceae Leguminosae Leguminosae Leguminosae Malvaceae

LAC: AN INTRODUCTION

Climate Lac insects can be cultured over a fairly wide range of tropics and sub¬ tropics and on a large number of host trees, 40° north and south of equator. Moderately hot to mild temperature and humid conditions are favourable for lac culture. Thus, lac production is limited to a few south, south-east and east Asian countries in the tropical forests region. A large part of India offers climate suitable for lac production.

. ..

MERITS OF LAC CULTIVATION IN INDIA It is good source of livelihood of limited-resource farmers, tribals

inhabiting sub-hilly tracts.

It requires no irrigation, meagre fertilizers, labour and pesticides. A good crop for marginal and degraded lands; no competition for land or farm operation with agricultural/ horticultural crops. Highly remunerative cultivation, a hectare of ber plantation with kusmi lac cultivation can provide net returns of Rs 3 to 5 lakh/year. It is like an insurance crop especially, during drought years as the crop is very good during such adverse climate. Lac cultivation involves significant women participation and helps ecosystem development. • Vast natural resources of untapped lac hosts are available for

. .

commercial exploitation. Rich traditional knowledge and skill in production and processing are available. Good infrastructural support for research, development and export is available. Nature’s unique gift of kusmi lac is not available in any other country. • LAC PRODUCING COUNTRIES

India, Thailand and the People’s Republic of China are the major producers of stick-lac and its derivatives; the first two are also the major exporters of lac products and share almost equally export market; while China’s production is mainly consumed in the domestic market. Indonesia, Bangladesh, Myanmar, Vietnam and Sri Lanka are the minor producers of lac. The present production of lac in India is about 20,000 tonnes per annum. The main lac-collecting centres in Thailand are Chiengmai, Obol, Denchai and Rahang. Bangkok is, however, the main trading centre. Thailand’s production and exports of lac commenced in 1950s and progressively eroded India’s share of the internationalmarket through keen pricing. Recent exports have been of the order of 7,000 tonnes annually, mainly of the partially refined seedlac. China’s main cultivation area for stick-lac is the province of Yunnan, where recent annual production volumes have been 4,000 to 5,000 tonnes

PROCESSING, CHEMISTRY AND APPLICATIONS OF LAC

of crude stick-lac and 2,000 to 3,000 tonnes of processed shellac, together with some quantity of lac dye. Production has also been initiated on a smaller scale in the province of Fujian since mid-1950s. Exports of shellac are comparatively small at approximately 500 tonnes per annum; Japan being its principal buyer. A Japanese company is operating a lac factory in Thailand. Lac industrial scenario: national and international In our country, the main lac-processing centre is at Balarampur, West Bengal, where lac is manufactured at cottage industry level. Besides, there are a few around at Kolkata (West Bengal), Chhattisgarh, Madhya Pradesh, Maharashtra and Jharkhand. In all, about 200 units of lac-processing centres are involved in the trade, in the country, ranging from very small to larger ones with the processing capacity of less than 100 kg to 5,000 kg per day. There are about 20 units in Germany, USA, China, Thailand and Japan. The individual capacities of these units are higher than an average Indian unit. A processing center is also reported at Pegu in Myanmar.

LAC COMPOSITION Raw lac (stick-lac) contains resin, wax, dye, insect body, bark of host trees as well as other impurities. This is, therefore, refined to obtain purified material of commerce (called shellac). The chemical composition and constituents of shellac have been discussed in chapters 3 and 4. The lac resin is a polyester complex of long-chain hydroxyfatty acids and sesquiterpenic acids. Indian lac dye is a mixture of at least 5 anthraquinone derivatives called laccaic acids. Lac wax is complex mixture of long-chain

acids, alcohols, esters and hydrocarbons.

LAC APPLICATIONS Some general information about applications of lac are given as follows:

Resin The first use of shellac as a protective coating appeared as early as 1590 in a work by an English writer who was sent to India to observe the country and its people. Commenting on the procedure for applying lac to wood still on the lathe he wrote â&#x20AC;&#x153;they take a piece of lac of what colour they will, and as they tume it when it commeth to his fashion they spread the lac upon the whole piece of wood which presently, with the heat of the turning (melteth the waxe) so that it entreth into the crestes and cleaveth unto it, about the thicknesse of a manâ&#x20AC;&#x2122;s naile: then they burnish it (over) with a broad straw or dry rushes so (cunningly) that all the woode is covered with all, and it shineth like glasse, most pleasant to behold, and continueth as long as the woode being well looked unto: in this sort they cover all

LAC: AN INTRODUCTION

kinde of household stuffe in India”. It’s interesting that many wood turners still finish this same method even today (Jewitt, 1935). Wax

In the United States, waxes used on citrus initially were paraffin based in 1930’s, evolved to solvent-based resins in late 1940’s. Use of camauba waxes was in vogue in late 1950’s but became less popular due to lack of shine. Waxes containing shellac and various alkali soluble resins plus adjuvants were introduced in early 1960’s and are being widely used in citrus-producing areas since then (Kaplan, 1986).

Dye Vinaya texts of Buddhists described use of lac dye in dyeing of fabrics. Kalidasa’s works contain descriptions of use of lac dye for cosmetic purposes. The original cultivation of lac was not for resin, but rather, for dye that gives the resin its characteristic colour. Use of lac dye can be traced back to 250 A.D., mentioned by Claudius Aelianus, a Roman writer, in a volume on natural history. The dye remained a valuable commodity until the mid-nineteenth century, when Perkins, an English chemist, synthesized first chemical ‘aniline’ dye, which killed natural dye industry. Ancient Chinese and Indian civilizations used the dye extracted from lac for dyeing silk, leather, as cosmetic rouge and a colouring for head ornaments.

Product standardization Lac being an export commodity, quality evaluation, particularly acceptable at international level, is of utmost importance as it assures reliability/consumer confidence, quality related product price, desired product/by-product recovery and promotes healthy manufacturing and trade practices. The Institute is actively associated with the Bureau of Indian Standards, New Delhi for formulating and finalizing different standards for different forms of lac and lac-based products for stringent quality control in the country. The institute represents CHD 23 sub-committee of the BIS meant for lac and lac-based products. Lac and lac products exports

Out of the different lac-based products exported during the VIII and IX Plan (Fig.1.3), there exists a tremendous potential for export of valueadded lac-based products (dewaxed decolourized lac, bleached lac, lac dye, aleuritic acid, isoambrettolide) provided a stable price structure is maintained.

PROCESSING, CHEMISTRY AND APPLICATIONS OF LAC

450-1 400-

Dewaxed shellac Bleached lac Aleuritic acid

350

1 I250300-

I200150UJ

100-

-A-

50-

2000-01

2001-02

-kc

2003-04 2002-03 Year

2004-05

2005-06

Fig. 1.3. Export of three value-added lac-based products-dewaxed shellac, bleached lac and aleuritic acid

LAC RELATED ORGANIZATIONS Some of the organizations, which are engaged in the support of the lac industry and the trade in India, are as follows:

Indian Institute of Natural Resins and Gums, Ranchi

The Indian Institute of Natural Resins and Gums (IINRG), is the nodal Institute at the national level for research and development on all aspects of lac, production, on-farm and off-farm training on lac production; processing, training on lac processing, product development; manufacture of lac-based products; entrepreneurship development training; repository of information; consultancy and quality evaluation service of lac and lacbased products for entrepreneurs, lac exporters and also co-operation at the national and international levels for formulation of standards of different lac and lac-based products. Its quality evaluation laboratory has received licence for the Quality Management Systems Certification from the Bureau of Indian Standards, New Delhi, in accordance with IS/ISO 9001:2000 to render laboratory services for collection, analysis, testing and reporting of lac and lac-based product samples. Its website is www.icar.org.in/ilri. Shellac and Forest Products Export Promotion Council, Kolkata It is the nodal Export Promotion Council (formerly, Shellac Export Promotion Council, www.shellacepc.com) to promote exports of “Minor Forest Produce” and registering authority for related exporters under the Foreign Trade Policy. Its mission is “to enable and assist members of the Shellac Export Promotion Council to discharge their responsibilities and obligations under foreign trade policies and to strengthen the plans and initiatives for enhancing exports of shellac and lac-based products and to realize the full potential of exports from India through collective action.”

LAC: AN INTRODUCTION

It plays a catalytic role in promoting Indiaâ&#x20AC;&#x2122;s MFP exports, acting as a bridge between exporters and various government agencies to ensure smooth growth.

Institute of Forest Productivity, Ranchi Institute of Forest Productivity (www.envfor.nic.in/icfre/ifp/ijp.html) is an research and development organization under the aegis of the Indian Council of Forestry Research and Education (ICFRE), Ministry of Environment and Forests, Government of India. It is mandated to steer, undertake and co-ordinate research, development and extension in forestry sector in Bihar, Jharkhand, West Bengal and Sikkim. The Institute aims at enhancing productivity of faunal and floral resources, conservation of biodiversity, eco-restoration of degraded lands and protection of diverse and fragile ecosystems unique to the region. Jharkhand State Co-operative Lac Marketing and Procurement Federation Ltd, Ranchi The main objective of the Federation (www.jascolampf.com) is to help lac growers in obtaining remunerative price of their produce. It also undertakes procurement of raw lac, processing into different products and their disposal. Tribal Co-operative Marketing Development Federation of India Ltd, New Delhi This is a body of Government of India (www. trifed. co. in) for sustainable development of natureâ&#x20AC;&#x2122;s bounty for tribal people through marketing of non-wood produce. Besides other activities, it provides assured market and remunerative prices for tribal produce and undertakes price support operations wherever and whenever required.

FUTURE PERSPECTIVES Stability of lac prices during the recent years despite steady increase in production is indicative of strong demand of lac. Feedback from lac industries also supports this contention. There is increased stress on use of eco-friendly and safe natural material particularly associated with human contact and consumption. Thus, very good increase in demand of lac is envisaged. There is already demand picking up for bleached lac, and lacdye in food processing industry and aleuritic acid in perfumery. Two-fold increase in demand for lac is anticipated over the next decade. Indian lac industry would have to assure steady supply and price of lac to meet demands. To match this, we have to develop and maintain a suitable pace of increase in lac production in the country to minimize any adverse impact on the processing and supply of lac.

PROCESSING, CHEMISTRY AND APPLICATIONS OF LAC

Based on the current trend, it is envisaged that by 2012, there will he shortage of lac host-plants, particularly palas and kusum, due to their exploitation for timber and other purposes; increase in soil salinity, accompanied by decrease in water-table; decrease in working hands in rural areas due to migration to cities and increased education; increase in prices of inputs such as fertilizers and pesticides; higher level of air pollution especially, due to industries and vehicles; and abnormal changes in temperature due to climate change. While increase in price of inputs such as pesticides, fertilizers, accompanied by water scarcity might not have direct impact on the lac cultivation and utilization, but migration of rural populace to urban areas, coupled with decreasing forest cover, insect mortality due to air pollution and abnormal temperature rise and loss of interest in farm-related activities could have an adverse impact on the lac production. Despite the advantages of lac, the challenge posed by the cheaper available synthetic substitutes, constant product refinement and development of newer areas are imperative for sustaining existing application areas and to offset eroding areas. The consumption of lac is mainly due to several of its unique properties, making it virtually indispensable in certain areas of its application. Besides, demand for lac dye is also showing revival in food industry. Yet, complex interactions of various marketing forces, both intra- and extra-sectoral, might adversely affect the demand pattern of the commodities. A concerted effort is required to be undertaken by all those involved in the lac trade to achieve goal of enhancing lac productivity, production, raw material or process product quality export, reduced cost, diversified uses, domestic consumption, employment and provide assured source of livelihood to resource poor population of sub-hilly tracts of different states of the country described above. The lac industry is of great importance to India not only that it earns valuable foreign exchange, but it provides employment to a considerable number of people, e.g cultivators, middlemen, processors, brokers, exporters, product manufacturers etc. Any government or quasi-government intervention to stabilize lac prices can ease out fluctuations in prices of raw material as well as processed products. It would augment continuous demand of the product by the users, who, at times of high price, start looking for other alternatives. It is hopefully envisaged that in the coming years, lac cultivation and processing would generate enough employment to unemployed tribal youth and women at village level, ensuring livelihood support to lac-growers and others associated with lac trade. Trends in export of various grades of processed lac from the country, over the past decade are indicative of increase in value-added products. It is hoped that in future value-addition of lac products will be maximized

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