Investigation of Bleach Active Compounds in Washing Bath Assoc.Prof. Tanja Pu iæ, Ph.D.
Janka Jelièiæ, B.Sc.*
Mila Nuber, M.Sc.*
Prof. emeritus Ivo Soljaèiæ, Ph.D.
University of Zagreb, Faculty of Textile Technology
Zagreb, Croatia
*
Zagreb, Croatia
e-mail: tpusic@ttf.hr UDK 677.027.268:677.016 Received January 30, 2007Original scientific paper
The washing effects of standard EMPA fabric with special soilings, laboratory
soiled percale fabric and control RAL fabric have been investigated. Washing with
addition of hydrogene peroxide or peracetic acid was performed in the laborato-
ry machine, Lavamac, at 60 and 80°C. The washing performance of the bleach
active compounds was evaluated in the bath composition with nonionic surfactants
and sodium hydroxide for regulation of pH. Builders were not added in the laun-
dry bath. Pre-washing was performed in the alkaline bath, pH 9-10 with different
additions of enzymes and sodium hypochlorite. It was found that colored soiling
such as red pepper chutney, red wine and fruit juices were removed at both tem-
peratures, but more efficiently at the higher temperature. The washing effects with
hydrogen peroxide were better than with peractic acid. The protein soiling as
cocoa, milk/blood/ink and yolk were efficiently removed at lower washing tem-
perature with enzymes in pre-wash. The effect of non-ionic surfactants was im-
proved with enzymes. Pre-washing with sodium hypochlorite, followed by wash-
smaller
ing at 80 °C after 25 cycles, caud damage to textiles. The chemical wear s and
the decrea of tensile strength and depolymerization were higher than the limit-
ed values according RAL. The damage of textiles washed at 60 °C was not evi-
dent. The whiteness degree of textiles after 25 cycles was below the limited value.
The whiteness of the brightened fabric was not improved during 3 cycles indicat-
出国中介ing that the concentration of FBA should be incread or a different type of FBA
should be applied.
Key words: bleach active compounds, washing with hidrogene peroxide, wash-
ing with peracetic acid, washing effects
1. Introduction Bleaching agents are important in-gredients of a detergent composi-tion. The main pu
rpo is to remove bleachable stains becau the sur-factants and builders are not enough efficient to remove the stains dur-ing washing. The oxidative agents destroy chromophores of colored stains. The most dominant bleach-es are sodium hypochlorite, able to bleach in the cold bath, and sodium perborate as the most frequently encountered source of hydrogen peroxide. Its oxidation is evident at
a higher temperature, starting at
60 °C, and the optimum is reached
at 90 °C. The u of sodium percar-
bonate has gained the importance in
tho countries where the boron
compounds are restricted or banned
from environmental reasons or re-
gulations [1].
The washing habits in USA are
specified by low temperature baths
in the prence of sodium hypochlo-
rite as the bleach active compound.
The usage of hypochlorite in the
finishing of textiles in the Europe is
banned from environmental reasons
due to reaction of active chlorine
with amino acids producing toxic
compounds in the wastewaters [2].
Sodium hypochlorite is still applied
in the industrial laundries due to
disinfection feature. During the last
decade the satisfactory bleaching
potential of hydrogen peroxide in
the houhold and commercial
laundries has been achieved by in-
corporation of bleach activators.
The result is a peracid able to bleach
and wash at lower temperature than convenient. The acylating agents, TAED (tetraacetylethylenediamine) and NOBS (sodium nonanoyl-oxy-benzenesulfonate) react with hydro-gen peroxide producing peracids; peracetic in the ca of TAED and peroxynonanoic in the ca of NOBS. The low temperature bleaching effectiveness is evident even at 40 °C. The antimicrobial, anti
virus and antifungal perform-ance of bleach activators is known from literature data. The effective-ness is lower than in the ca of sodium hypochlorite [3, 4].
It was attempted to apply the origi-nal peracetic acid in the houhold washing machine, but it was very difficult due to its crumble during storage and trouble of incorporation in the powder detergent formula-tions. In spite of this, the application of peracetic acid in the textile indus-try and industrial laundry ctor is still actual [5, 6]. The main advan-tage of peracetic acid as bleaching agent is no n on the traces of heavy metals in the bleaching bath that are able to cau the damage of textiles in the ca of bleaching with hydrogen peroxide. The environ-mental reference of peracetic acid when compared with perborate is safety. The effectiveness of perace-tic acid is very similar to hydrogen peroxide utilized with bleach acti-vators. This is the benefit due to minimization of energy as well as decread amount of textiles washa-ble at high temperatures [3]. The tendency to low temperature wa-shing procedures has been actualized by increasing the portion of synthe-tic and regenerated fibres in textiles. The most frequently ud pro-gramme in the laundries includes the combination of two bleaching agents, sodium hypochlorite and hydrogen peroxide.
Peroxide is added into the washing bath, while hypochlorite, as disin-fection agent, is added into the rins-ing bath. It was proved that disinfec-tion feature of hypochlorite can be deactivated by residual a
ctive oxy-gen from perborate bleaching when
added in the start rinsing bath. It is
recommended to add the hypochlo-
rite at least 6 batches behind the
washing unit [7]. It is impossible to
follow in the laundries supplied
with low capacity equipment. The
most frequent recommendation is
addition of hypochlorite in the pre-
washing bath to avoid its crumble
caud by active oxygen. Hydrogen
peroxide is dod with other com-
ponents in the washing bath. It is ap-
plicable for the component wash-
ing, where amounts of particular
liquid component are dod auto-
matically in the machine.
It was interesting to investigate the
远程教育专升本influence of the components on
the effectiveness of stain removal.
For this purpo only a nonionic
surfactant was ud. Sodium hy-
droxide was added for pH regula-
tion and no other builders due to
exact evaluation of the bleaching
agents. The primary and condary
effects were compared as a result of
different combinations of bleaching
agents with or without enzymes in
the pre-washing bath.
2.Material, treatment and
testing methods
The investigation of different
bleach active compounds in the
washing bath was performed on the
EMPA test fabric No. 103 (EMPA-
六一儿童节发言稿
Eidgenössische Materialprüfungs
und Forschungsanstalt). Combined
EMPA washing test strips for Stain
Monitor IEC, EN 60456 strips (art.
103) consists of 8 different standard
stains (Tab.1).
GhiryÃ8 ÃÃ
!! Ã7yrhpurqÃÃ
ÃT vyrqà v uÃph i Ãiyhpx yv rÃ
vyÃ
ÃT vyrqà v uÃiy qÃ
!ÃT vyrqà v uÃp p hÃ
%ÃT vyrqà v uà vyx iy q v xÃ
$ÃT vyrqà v uÃv rqvhyÃiyhpxÃ
!!!ÃSh Ã
#ÃT vyrqà v uà rqà v rÃ
Tab.1 EMPA test fabric
Tab.2 Washing with addition of hydrogen peroxide
Additional testing was performed
on a laboratory soiled cotton percale
fabric. Different soils were applied:
yolk, cocoa, juice (peach/apple),
factory and domestic red pepper
chutney, coffee, lipstick Ro Crys-
tal No. 200 (Loreal), pumpkin oilcraftsmen
and grass were applied for the per-
cale fabric.
The characteristics of the percale
fabric were: 100% cotton; weight
per m2 190 g/m2; warp thread den-
sity: 36 threads/cm and weft thread
density: 27 threads/cm; warp yarn
count: 16.6 tex and weft yarn count:
29.4 tex; sateen weave: 5/1.
Secondary effects were controlled
after frequent washing of standard
control cotton fabric, with no fluo-
rescent whitening agents or addi-
tives according to DIN 53 919-1.
Washing was performed in the La-
vamac 7 laboratory machine. The
tested fabrics were agitated with a cotton ballast fabric (5 kg) at 40 °C in the pre-washing and washing bath following the standard proce-dure during 25 minutes at 60 and 80°C (Tab.2 and 3). After washing the fabrics were rind three times and neutralized with acetic acid. Cen-trifugal agitation followed pre-washing and rinsing procedures.
Dosing particular components from the tank devices was done automa-tically according to the following programmes (Tab.4).
Pre-washing bath was alkaline,from pH 9 to pH 10, while the pH of washing baths was approx. 10with peroxide and between pH 7and 8 with peracetic acid as bleach active compounds.
Standard control RAL and percale cotton fabrics were washed accord-ing to the following programmes (Tab.2 and 3) through 25 cycles.Secondary effects were tested after 25 cycles according to ISO 4312[8]. 3. Results and discussion Primary and condary washing effects were evaluated. The results obtained on the EMPA test strip fab-ric (EMPA) are prented in Tab.5and 6. The washing performance of different bleach compounds in order to remove standard stain varied sig-nificantly.The red wine and blood stains on the cotton fabrics were almost com-pletely removed achieving a remis-sion value similar to bleached cot-ton. A higher washing temperature (80 °C) is more favorable for the removal of red wine stains. A low-er washing temperature (60 °C) is optimal only in pre-washing with sodium hypochlorite and washing with a peracetic acid component.This result was expected becau it is possible to remove a colored stain with bleaching agents. The same effectiveness of both washing tem-peratures is evident in the ca of blood where the main part of the Tab.3 Washing with addition of peracetic acid
Tab.4The composition of dosing components in the pre-washing and washing process 8 r ÃÃ8 v v ÃT shp h à v u Ãr rÃI v vpà shp h à v uÃhqqv v à sÃAX6à yir rà q p ÃÃT shp h à v uÃr rÃI v vpà shp h à v uÃhqqv v à sÃAX6à yir rà q p Ãh qÃr rà rh r Ã6yxhyvÃT qv Ãu q vqrÃh qà y ph i yh rÃIh8GPà ! $ Ãt y ÃC P à "$È ÃÃ7yrhpuÃhp v rÃhtr ÃÃ8C 8PPPC à $È ÃIr hyv h v ÃÃ
6pr vpÃhpvqà ' È Ã Tab.5Remission values (R 460) of EMPA test fabric before and after washing with hydrogen peroxide ÃÃS Ã È ÃGhiryÃ8 Ãà à à ! à " à # à $ à % Ã!! Ã7yrhpurqÃÃ&& ( Ã'! !$Ã' "!Ã'" #"Ã'! #(Ã'$ $"Ã'# %à ÃT vyrqà v uÃph i Ãiyhpx yv rà vyà $ Ã"" "$Ã!& &$Ã!( 'Ã" %'Ã"# &Ã"$ %%à ÃT vyrqà v uÃiy qà % $(Ã&" !(Ã&! $#Ã&& %'Ã&" '#Ã&' !Ã&! %(à !ÃT vyrqà v u
Ãp p hà $ (&Ã"# $Ã"% ' Ã#( "'Ã"' #'Ã"& '%Ã#% #(à %ÃT vyrqà v uà vyx iy q v xà " "&Ã!$ !Ã!" #Ã## #Ã" "%Ã!' ( Ã#! "&à $ÃT vyrqà v uÃv rqvhyÃiyhpxÃ!( $ Ã"# $ Ã"! &Ã"! #Ã$% !'Ã"$ "Ã"$ "!Ã!!!ÃSh Ã$% '%Ã%$ ("Ã%$ % Ã%$ & Ã%( # Ã%( Ã%( ('à #ÃT vyrqà v uà rqà v rÃ## ' Ã%" $ Ã%! "&Ã%# $'Ã&& #Ã& !'Ã&! #!à Tab.6 Remission values (R 460) of EMPA standard fabric before and after washing with peracetic acid ÃÃS Ã È ÃGhiryÃ8 à Ã! Ã! ! Ã! " Ã! # Ã! $ Ã! % Ã!! Ã7yrhpurqÃÃ&& ( Ã'# %&Ã'! % Ã'" &$Ã'# $"Ã'$ 'Ã'$ !!à ÃT vyrqà v uÃph i Ãiyhpx yv rà vyà $ Ã!% '$Ã!$ %$Ã!& Ã"" "Ã!# '$Ã!( à ÃT vyrqà v uÃiy qà % $(Ã&# $&Ã%( & Ã&# '&Ã&# #$Ã% '%Ã&" #à !ÃT vyrqà v uÃp p hà $ (&Ã"' 'Ã"& % Ã#( $#Ã"# Ã"$ 'Ã#! #"à %ÃT vyrqà v uà vyx iy q v xà " "&Ã!& &&Ã!! $&Ã"& $'Ã!" !$à ( $Ã"# " à $ÃT vyrqà v uà Ã!( $ Ã#( !!Ã"! $!Ã"" &"Ã#% ' Ã"" &(Ã"$ (&Ã!!!ÃSh Ã$% '%Ã%' "'Ã%# Ã%" &$Ã%& $#Ã%' Ã%& #!à #ÃT vyrqà v uà rqà v rÃ## ' Ã&" ' Ã$' $!Ã% " Ã&& &!Ã&! " Ã%& #(Ã
stain is removed during pre-wash-ing. Enzyme prence is important for the removal of this stain. The addition of enzyme in the per-oxide and peracetic washing bath is positive due to a prominent protein nature of cocoa with milk stain. The removal of a mixed milk/blood/ink stain consisting of two protein bad components is similar. The washing performance of the detergent with
an enzyme component is prominent. The positive influence of a low washing temperature on the remnipple
ov-al of this stain is evident. The wash-ing performance of peroxide is more favorable than peracetic acid in this ca, too.
Carbon black in olive oil is a very obstinate stain. High-temperature washing is more applicable when pre-washing was performed in a hypochlorite bath.
Similar results were obtained after washing of the soiled percale fabric. The washing effectiveness of all washing baths was the same in the removal of red wine and fruit juice stains. Bleach active compounds are key ingredients for the stains. The washing results with peroxide were slightly better than with per-acetic acid. Pre-washing with hy-pochlorite is preferred to peroxide for the removal of lipstick stains in all wash baths.
Protein stains such are yolk and cocoa are better removed at 60 °C than at 80 °C in the peroxide bath. Peracetic acid as a bleach active compound was less effective than peroxide, but washing performance was satisfactory. The stains were removed almost completely in the peroxide bath at 60 °C. In most cas-es a red pepper chutney stain was also removed. Low-temperature washing is more efficient. Pumpkin oil is removed in washing both at 60 and 80 °C, but peracetic acid was more efficient than perox-ide.
The testing of EMPA standard stains, where intensity and density of soil are equal, is more convenient in order to ass the washing performance.The intensity, depth and density of
laboratory deposited soils on the
percale fabric are different and the
washing results were expresd de-
scriptively. In general, the tested
oncallstains were removed in low-tempe-
rature washing baths and a tempe-
rature ri in the ca of protein
stains produce a negative result due
to the destabilization and destruc-
tion of enzymes. The cond reason
was the u of only one type of sur-
factant in the washing bath. The
effectiveness of nonionic sur-
factants in high-temperature wash-
ing was weaker due to the cloud
point. Literature data showed that the
best washing performance of noni-
onic surfactants is around the cloud
point [1]. A higher washing tempe-
rature combined with hypochlorite
pre-washing was favorable only for
the removal of obstinate oil stains
(carbon black/olive oil). The testing
results obtained are in good correla-
tion with theoretical knowledge.
Secondary effects are also impor-
tant for the washing performance,
and they were evaluated after mul-
tiple cycles. The evaluation criteria
after 3 and 25 wash cycles include
testing breaking strength, polyme-Tab.7Secondary effects of standard control RAL fabric after 25 cycles in the washing bath with hydrogen peroxide and peracetic acid
ÃC P ÃÃ8C 8PPPCÃ
Q t h rÃ'AÃ
È Ã
ÃQÃ È ÃQ t h rÃ'AÃ
È Ã
ÃQÃ È Ã
à à " à (Ã! à ! à " à %à ! Ã% "à "à (Ã! ! Ã& (à à #à " Ã$ %à %à '!Ã! " Ã& "à !'à "à # à $à '(à (Ã! # à % %à '"à ! à $ Ã$ &à " à $"Ã! $ à %à #"à "à % Ã& (à !(à ##Ã! % à 'à " à $"Ã
Tab.8Whiteness degree with (W) and without UV (W*) stimulation of percale and standard control RAL fabrics before and after 1, 3 and 25 washing cycles
rization degree, Einhut chemical wear, whiteness degree with and without UV stimulation, ash content of standard control (RAL) fabric and whiteness degree of the percale fabric (Tab.7).
The limit value of breaking strength decrea (D F) after 25 cycles must not exceed 15% according the Ger-man regulations prescribed by RAL GZ-992/1 [9, 10]. The tested pre-wash and wash programmes ful-filled the RAL requirement, but the exception is only the sample washed with peracetic acid at 80 °C pre-washed with sodium hypochlorite (2.4). In general, better effects were obtained in peroxide than in perace-tic wash bath. A high washing tem-perature caud a higher damage of textiles than a low temperature. The decrea of the breaking strength is below 10% when the washing bath contains peroxide without hy-pochlorite in the pre-wash bath. Einhut chemical wear, s, of stan-dard RAL fabric pre-washed with hypochlorite, washed at 80 °C with peroxide and peracetic acid, exceed the limit value of 0.5 according RAL. The sodium hypochlorite, added in a small amount, damages textiles. A similar effect is the result of elevat-ed temperature. The washing per-formance at 60 °C is very good in each ca. The damage of textiles is below 0.3 indicating good washing performance according RAL. The ash content of RAL fabric after 25 washing cycles exceeded the limit value of 0.7% only in one ca. Meanwhile, the results are good due to washing conditions in hard water without addition of builders.The required whiteness degree was
not achieved in the tested wash pro-
grammes which can be explained by
the fact that the standard control
fabric was only pre-bleached
(Tab.8), and the basic whiteness is
only 77.2. The whiteness degree of
the percale fabric, previously
bleached with FWA, ranges from 10
to 15 units higher than in the ca
of RAL fabric. The RAL require-
ments are not fulfilled and a possi-
wap中文是什么意思ble correction is the incread
amount of FWA or application of
another FWA type. Remission
curves (Fig.1a) show that the re-
moved amount of FWA during
washing was compensated from the
new bath. The cumulative effect of
FWA is more pronounced on thehotstuds
RAL fabric becau it was not pre-
viously saturated with FWA
(Fig.1b).
4. Conclusion
The effectiveness of the tested wash
programmes is confirmed only in
the ca of colored stains such as red
wine, red pepper chutney and fruit
juices. The performance of bleach
active compounds able to destroy
colored pigments is evident. Better
results were obtained with peroxide
in comparison with peracetic acid.
Removing protein stains such as
coffee, yolk, milk and cocoa is more
efficient at 60 °C than at 80 °C,
where features of enzymes and no-
nionic surfactants are complete.
Removal of carbon black was effi-
cient at higher wash temperatures
when hypochlorite was a compo-
nent of the pre-wash bath.
The choice of washing procedure
would be bad on the soil type to
be removed.
Secondary washing effects tested
by standard fabric according RAL
are under tolerances.
Chemical wear of RAL fabric ex-
ceeded the limit value only after
frequent pre-washing with hy-
pochlorite, followed by washing at
80 °C, which should be taken in
consideration.
It is possible to achieve the optimal
whiteness through the additional
testing of concentration range as
well as different type of FWA.
R e f e r e n c e s:
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Wiley-VCH Verlag GmbH, Wein-
heim, 2002
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upotrebe natrijevog hipoklorita za
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zagaðivanje otpadnih voda, Tekstil
46 (1997.) 3, 139-144
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la, knjiga 1, Sveuèili te u Zagrebu,
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[4]Cai J.Y. et al: Bleaching of cotton
and cotton/wool blends with
TAED and NOBS activated perox-
ide systems, AATCC Book of Pa-
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[6]Hickman W.S.: Peracetic acid and
its u in fibre bleaching, Rev. Pro-
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[7]Gottlicher R.: Dezinfekcija u ku-
pelji za ispiranje natrijevim hipok-
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[8]ISO 4312: Surface active agents -
Evaluation of certain effects of laun-
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for unsoiled cotton control cloth
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parameters for washing in laun-
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niènih tekstilij, Tekstilec 49 (2006)
4-6, 72-80
Fig.1Remission curves of unwashed and washed a) PERCALE and b) standard control (RAL) fabrics
