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Bleach systems to deliver hygiene benefits in laundry detergents
Consumers require new aspects of performance from detergent components, driving the demand for laundry detergents with ‘hygiene’ or ‘sanitising’ claims. Jane Mathews and Eve De Maesschalck of Lubrizol Advanced Materials explain the importance of bleach systems in laundry detergents where hygiene effectiveness is key.
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overnments and the
Discussion and results
Figure 2). Results show detergent alone fails
World Health Organization
Within a laundry detergent formulation,
to pass the ASTM test (49g detergent with
have released a variety
a bleach system is primarily employed
12 minutes contact time at 30°C), which
of guidelines and
for the removal of coloured bleachable
requires a Log 3 reduction in bacteria to be
recommendations to manage, control
stains through the oxidation of stains
achieved. However, the addition of TAED/
and reduce the spread of diseases. The
either on a fabric surface or in the
PCS to deliver 150ppm PAAH clearly passes
most basic protection usually involves
wash liquor. In addition to stain removal
the ASTM E2406-09 test.
frequent hand washing with soap and
and maintaining the colour of white
water or using alcohol-based hand rub.
textiles, the bleach system also provides
However, disinfecting clothes, linens and
the functions of ensuring fabric and
Preventing microbial contamination
washing machines can also help reduce
machine hygiene. The most well-
It has been widely reported that microbial
possible spread of germs and ensure
established laundry bleach system is
build-up can occur in washing machines3.
hygiene in the home.
the bleach activator TAED (tetra acetyl
The impact of ineffective biocidal control
ethylene diamine) which is used
can result in the appearance of unsightly
Historically, laundry detergents have been employed to clean clothing and domestic household items, primarily to remove specific stains from the laundry wash load. Yet dirt and microbes can contaminate textiles. Clothing and linen are a risk factor for transmission
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in conjunction with sodium percarbonate (PCS) to form
As laundry wash habits peracetic acid (PAAH), and machine wash shown in the reaction in conditions continue to evolve globally, the focus Figure 1. on sustainability presents PAAH generated from challenges to detergent formulators. TAED is gentle the PCS/TAED contained on the environment, readily biodegradable, and of very in powder detergent low toxicity, delivering formulations is responsible the safe generation of PAAH. for low temperature
of infections and illnesses. The spread of diseases via soiled clothing,
bleaching and broad-spectrum biocidal performance ensuring both the
dark coloured biofilms, which adhere to the inner machine seal, fabric conditioner dispensing drawer and sump (see Figure 3). These biofilms can detach during the wash cycle and attach to washed fabrics contaminating the clean clothes and resulting in the need to re-wash fabrics. The results of testing under multicycle washing conditions at 30°C, in the presence and absence of an activated bleach system, are shown in Figure 4. The gradual build-up of microbial
as well as malodour issues, can be
washing machine and laundered fabrics
contamination over 30 wash cycles
prevented through the use of laundry
are hygienically clean¹. The hygiene
is clearly indicated when a non-
detergents with antimicrobial efficacy.
benefit delivered through the bleach
bleach detergent is used with a fabric
Over recent years several changes
system is now becoming increasingly
conditioner. After only 10 cycles, the total
have occurred in the laundry detergent
important, particularly under conditions
aerobic bacterial count reaches Log 4 (10
market which have in turn driven changes
of high soil loading and as high
000 bacteria cells/cm³), in the sump and
in consumer washing practises. The
temperature washing is now less frequent,
drum. This level of bacteria amounts to
heating of water in the washing machine
preventing thermal disinfection.
hygiene concerns.
cycle is widely recognised as the activity
Many washing machines also have the
Malodour was also noted in the
that consumes the most energy. To
option of quick wash cycles, which include
machine from 10 cycles, again indicating
address the needs of sustainability,
a reduced length of main wash time and
a microbial increase. This build up can
consumers are advised to wash at lower
result in reduced exposure to the biocidal
be reduced through the presence of a
wash temperatures to deliver energy
effect of detergent and temperature2.
bleaching agent generating 130ppm
savings. Additionally, the amount of water
In the absence of a bleach system,
used in a wash cycle has decreased over
ineffective control of microorganisms
the last 20 years.
on fabrics can potentially cause health
A study by Lubrizol Advanced
problems for society’s most vulnerable,
Materials demonstrates that the use of
including young children, the elderly
tetraacetylethylenediamine (TAED) in
and people with compromised
combination with sodium percarbonate
immune systems2.
(PCS) can deliver effective hygiene
Testing has shown that in the
performance benefits and compensate
absence of bleach a reduced kill of
for the loss of hygiene effectiveness of
microorganisms is delivered – illustrated
washing at lower temperatures.
in the ASTM HE laundry test E2406-09 (see
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| APRIL 2020 | P C Review
Figure 1: Bleach activator chemistry of TAED used in conjunction with a peroxide source to form PAAH in a laundry detergent
