Use of graft polymers based on polyalkylene oxides as grayness inhibitors in the wash and aftertreatment of textile material containing synthetic fibers

A detergent containing as grayness inhibitor in the wash and aftertreatment of textile material containing synthetic fibers graft polymers obtainable by grafting PA0 (a) polyalkylene oxides which have a number average molecular weight of from 300 to 100,000 and are based on ethylene oxide, propylene oxide and/or butylene oxide, with PA0 (b) at least one vinyl ester derived from a saturated monocarboxylic acid containing 3 to 6 carbon atoms, a methyl or ethyl ester of (meth)acrylic acid and optionally mixtures of at least one of the monomers mentioned and up to 95% by weight of vinyl acetate in a weight ratio (a):(b) of from 1:02 to 1:10.

Legislation in many countries makes it necessary to substantially reduce 
the phosphate content in detergents or to supply phosphate-free 
detergents. If, however, the phosphate content in detergents is reduced, 
the washing action of the products suffers. Phosphates act not only as 
sequestrants for alkaline earth metal ions but also as incrustation and 
grayness inhibitors. While the problem of incrustation, ie. deposits of 
mineral origin on the wash, can be successfully dealt with by replacing 
the phosphates in detergents by other substances, this is not the case 
with the problems of graying, ie. the redposition of soil particles and 
greases on the wash during washing. The problem of graying occurs in 
particular in fabrics containing synthetic fibers, in particular in 
polyester containing textiles. 
U.S. Pat. No. 4,444,561 discloses using copolymers which contain as 
characteristic monomers 
(a) from 50 to 90% by weight of at least one vinyl ester of a C.sub.1 - to 
C.sub.4 -aliphatic carboxylic acid, 
(b) from 5 to 35% by weight of at least one N-vinyl-lactam, 
(c) from 1 to 20% by weight of at least one monomer containing basic 
groups, or salts or quaternization products thereof, and 
(d) from 0 to 20% by weight of at least one other monomer free of carboxyl 
and basic groups and copolymerizable with monomers (a), (b) and (c), as 
copolymerized units, 
as grayness inhibitors in the wash and aftertreatment of textile material 
containing synthetic fibers. 
U.S. patent application Ser. No. 914,267 discloses using graft polymers 
obtainable by grafting 
(a) polyalkylene oxides of a molecular weight (by number average) from 
2,000 to 100,000 based on ethylene oxide, propylene oxide and/or butylene 
oxide with 
(b) vinyl acetate in a weight ratio of (a):(b) from 1:0.2 to 1:10 and whose 
acetate groups may optionally have been hydrolyzed up to 15%, 
as grayness inhibitors in the wash and aftertreatment of textile material 
containing synthetic fibers.

It is an object of the present invention to provide other grayness 
inhibitors for detergents and grayness inhibitors for aftertreating 
textile material containing synthetic fibers. 
We have found that this object is achieved according to the invention by 
using as grayness inhibitors a graft polymer which is obtainable by 
grafting 
(a) a polyalkylene oxide having a number average molecular weight of from 
300 to 100,000 and based on ethylene oxide, propylene oxide and/or 
butylene oxide, with 
(b) at least one ester selected from the group consisting of a vinyl ester 
derived from a saturated carboxylic acid having 3 to 6 carbon atoms, 
methyl acrylate, ethyl acrylate, methyl methacrylate and/or ethyl 
methacrylate, and mixtures of at least one of the said monomers with up to 
95% by weight of vinyl acetate in a weight ratio (a):(b) of from 1:0.2 to 
1:10 and whose ester groups may optionally have been hyrolyzed up to 15 
mole %. 
The products to be used according to the invention are known for example 
from GB Pat. No. 922,457. The graft bases used are the polyalkylene oxides 
specified above under (a), which have a number average molecular weight of 
300 to 100,000 and are based on ethylene oxide, propylene oxide and/or 
butylene oxide. Preference is given to using homopolymers of ethylene 
oxide or ethylene oxide copolymers having an ethylene oxide content of 
from 40 to 99 mole %. Suitable comonomers for these copolymers are 
propylene oxide, n-butylene oxide and/or isobutylene oxide. Suitable are 
for example copolymers of ethylene oxide and propylene oxide, copolymers 
of ethylene oxide and butylene oxide, and also copolymers of ethylene 
oxide, propylene oxide and at least one butylene oxide. The ethylene oxide 
content of the copolymers is preferably from 40 to 99 mole %, the 
propylene oxide content from 1 to 60 mole % and the butylene oxide content 
in the copolymers from 1 to 30 mole %. Aside from straight-chain it is 
also possible to use branched homopolymers or copolymers as graft base. 
Branched copolymers are prepared by for example addition of ethylene oxide 
with or without propylene oxide and/or butylene oxides onto polyhydric low 
molecular weight alcohols, for example trimethylolpropane, pentoses of 
hexoses. The alkylene oxide unit can be randomly distributed in the 
polymer or be present therein as blocks. Preferably, component (a) 
comprises polyethylene oxides having a number average molecular weight of 
from 1,000 to 50,000. 
Components (b) comprises vinyl esters derived from a saturated 
monocarboxylic acid containing 3 to 6 carbon atoms, and also methyl 
acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate and 
mixtures of at least one of the abovementioned monomers with up to 95% by 
weight of vinyl acetate. Suitable vinyl esters which can be used as sole 
graft component are for example vinyl propionate, vinyl butyrate, vinyl 
valerate, vinyl i-valerate and vinyl caproate. Of the monomers of group 
(b), preference is given to using vinyl propionate, methyl acrylate or 
mixtures of vinyl propionate with up to 95% by weight of vinyl acetate. 
To prepare the graft polymers, the polyalkylene oxides of component (a) 
which come into consideration are grafted with the monomers of component 
(b) in the presence of free radical initiators or by the action of 
high-energy radiation, which includes the action of high-energy electrons. 
This can be done by dissolving the polyalkylene oxide in at least one 
monomer of group (b), adding a polymerization initiator and polymerizing 
the mixture to completion. The graft copolymerization can also be carried 
out semicontinuously by first introducing a part, for example 10%, of the 
mixture of polyalkylene oxide to be polymerized, at least one monomer of 
group (b) and initiator, heating to polymerization temperature and, after 
the polymerization has started, adding the remainder of the mixture to be 
polymerized at a rate comensurate with the rate of polymerization. The 
graft copolymers can also be obtained by introducing polyalkylene oxides 
of group (a) into a reactor, heating to the polymerization temperature and 
adding at least one monomer of group (b) and polymerization initiator 
either all at once, a little at a time or preferably uninterruptedly and 
polymerizing. 
Suitable polymerization initiators are in particular organic peroxides, 
such as diacetyl peroxide, dibenzoyl peroxide, succinyl peroxide, 
di-tert-butyl peroxide, tert-butyl perbenzoate, tert-butyl perpivalate, 
tert-butyl permaleate, cumene hydroperoxide, diisopropyl 
peroxodicarbamate, bis(o-toluoyl) peroxide, didecanoyl peroxide, 
dioctanoyl peroxide, dilauroyl peroxide, tert-butyl perisobutyrate, 
tert-butyl peracetate, di-tert-amyl peroxide, tert-butyl hydroperoxide and 
also mixtures thereof, redox initiators and azo starters. 
The graft polymerization takes place at from 50.degree. to 200.degree. C., 
preferably at from 70.degree. to 140.degree. C. It is customarily carried 
out under atmospheric pressure, but can also be carried out under reduced 
or superatomspheric pressure. If desired, the graft copolymerization 
described above can also be carried out in a solvent. Suitable solvents 
are for example alcohols, eg. methanol, ethanol, n-propanol, isopropanol, 
n-butanol, sec-butanol, tert-butanol, n-hexanol and cyclohexanol, and also 
glycols, such as ethylene glycol, propylene glycol and butylene glycol, 
and also the methyl or ethyl ethers of dihydric alcohols, diethylene 
glycol, triethylene glycol, glycerol and dioxane. The graft polymerization 
can also be carried out in water as solvent. In this case, the first step 
is to introduce a solution which, depending on the amount of added 
monomers of component (b) is more or less soluble in water. To transfer 
any water-insoluble products which form during the polymerization into 
solution, it is possible for example to add organic solvents, for example 
monohydric alcohols having 1 to 3 carbon atoms, acetone or 
dimethylformamide. However in the graft polymerization in water it is also 
possible to transfer the water-insoluble graft polymers into a finely 
divided dispersion by adding customary emulsifiers or protective colloids, 
for example polyvinyl alcohol. The emulsifiers used are for example ionic 
or nonionic surfactants whose HLB value is within the range from 3 to 13. 
For the definition of the HLB value reference is made to the paper by W. 
C. Griffin in J. Soc. Cosmet. Chem. 5 (1954), 249. 
The amount of surfactant, based on the graft polymer, is from 0.1 to 5% by 
weight. If water is used as the solvent, solutions or dispersions of graft 
polymers are obtained. If solutions of graft polymers are prepared in an 
organic solvent or in mixtures of an organic solvent and water, the amount 
of organic solvent or solvent mixture used per 100 parts by weight of the 
graft copolymer is from 5 to 200, preferably from 10 to 100, parts by 
weight. 
The weight ratios of components (a):(b) in the graft polymer is from 1:0.2 
to 1:10, preferably 1:0.5 to 1:6. Such graft polymers have a K value of 
from 5 to 200, preferably from 5 to 70 (determined according to H. 
Fikentscher in 2% strength by weight solution in dimethylformamide at 
25.degree. C.). After the graft polymerization the graft polymer may be 
subjected to a hydrolysis where up to 15 mole % of the grafted-on monomers 
of component (b) may be hydrolyzed. For instance, the hydrolysis of graft 
polymers prepared using vinyl esters as component (b) gives graft polymers 
containing vinyl alcohol units. The hydrolysis can be carried out for 
example by adding a base, such as sodium hydroxide solution or potassium 
hydroxide solution, or alternatively by adding acids and if necessary 
heating the mixture. 
The graft polymers described above are used according to the invention in 
detergents of reduced phosphate content (which is to be understood as 
meaning a phosphate content of less than 25% by weight of sodium 
triphosphate) or in phosphate-free detergents. For grayness inhibition in 
the wash, the graft polymers described above are added to commercially 
available detergent formulations in an amount of from 0.1 to 5, preferably 
from 0.3 to 3, % by weight, based on the detergent mixture. For addition 
to the detergent formulation the graft polymers can be in the form of a 
paste, of granules or of a highly viscous material, or as a dispersion or 
solution in a solvent. The graft polymers can also be adsorbed on the 
surface of additives, for example sodium sulfate, or builders (zeolites) 
and other solid assistants making up the detergent formulation. 
Commercially available pulverulent detergents whose phosphate content is 
below 25% by weight and those which contan no phosphate at all contain as 
an essential constituent surfactants, for example C.sub.8 - to C.sub.12 
-alkylphenol ethoxylates, C.sub.12 - to C.sub.20 -alkanol ethoxylates, and 
also block copolymers of ethylene oxide and propylene oxide. The 
polyalkylene oxides are solid substances at from room temperature to 
50.degree. C. and readily soluble or dispersible in water. They comprise 
in particular linear or branched reaction products of ethylene oxide with 
propylene oxide and/or isobutylene oxide which have a block structure or 
which can also have a random structure. The end groups of the polyalkylene 
oxides are capped or uncapped. The term capping as used herein is to be 
understood as meaning that the free OH groups of the polyalkylene oxides 
can be etherified and/or esterified and/or aminated and/or reacted with 
isocyanates. 
Other suitable surfactants are anionic surfactants, such as C.sub.8 - to 
C.sub.12 -alkylbenzenesulfonates, C.sub.12 - to C.sub.16 
-alkanesulfonates, C.sub.12 -to C.sub.16 -alkylsulfates, C.sub.12 - to 
C.sub.16 -alkylsulfosuccinates and sulfated ethoxylated C.sub.12 - to 
C.sub.16 -alkanols. Pulverulent detergents customarily contain from 5 to 
20% by weight of a surfactant or a mixture of surfactants. The surfactant 
content in liquid deteregents is within the range from 15 to 50% by 
weight. 
Pulverulent detergents may optionally also contain polycarboxylic acids or 
salts thereof, for example tartaric acid and citric acid. 
A further important constituent of detergent formulations are incrustation 
inhibitors. These substances are for example homopolymers of acrylic acid, 
methacrylic acid and maleic acid and copolymers, for example copolymers of 
maleic acid and acrylic acid, copolymers of maleic acid and methacrylic 
acid and copolymers of (a) acrylic acid and/or methacrylic acid with (b) 
acrylic esters, methacrylic esters, vinyl esters, allyl esters, itaconic 
esters, itaconic acid, methylenemalonic acid, methylenemalonic esters, 
crotonic acid and crotonic esters. Also suitable are copolymers of olefins 
and C.sub.1 - to C.sub.4 -alkyl vinyl ethers. The molecular weight of the 
homopolymer or copolymer is from 1,000 to 100,000. The incrustation 
inhibitors are used in an amount of from 0.5 to 10% by weight in 
detergents. 
Further possible constituents of detergents are corrosion inhibitors, 
monomeric, oligomeric and polymeric phosphonates, ether sulfonates based 
on unsaturated fatty alcohols, for example oleyl alcohol ethoxylate butyl 
ether and alkali metal salts thereof. Pulverulent detergents may also 
contain zeolites in an amount of from 5 to 30% by weight. The detergent 
formulations may also contain bleaching agents. If bleaching agents are 
used, they are customarily employed in amounts of from 3 to 25% by weight. 
A suitable bleaching agent is for example sodium perborate. The detergent 
formulations may also contain bleach activators, softeners, antifoams, 
scent, wash alkali (sodium carbonate), optical brighteners and enzymes. 
Additives, for example sodium sulfate, may be present in the detergents in 
an amount of from 10 to 30% by weight. 
The graft polymers described above can also be used as additives in liquid 
detergents. Liquid detergents contain as admixture component liquid or 
even solid surfactants which are soluble or at least dispersible in the 
detergent formulation. Suitable surfactants for this purpose are those 
products which are also used in pulverulent detergents, and also liquid 
polyalkylene oxides or polyalkoxylated compounds. If the graft polymers 
are not directly miscible with the other constituents of the liquid 
detergent, a homogeneous mixture can be prepared by means of small amounts 
of solubilizers, for example water, or of a water-miscible organic 
solvent, for example isopropanol, methanol, ethanol, glycol, diethylene 
glycol or triethylene glycol. 
The graft polymers are also suitable for use as additives in the 
aftertreatment of textile material containing synthetic fibers. For this 
purpose they are added to the final rinse bath of a washing machine cycle 
either together with a fabric conditioner customarily used at this 
juncture or, if a fabric conditioner is undesirable, alone in place of the 
fabric conditioner. The quantities used are from 0.01 to 0.3 g/l of wash 
liquor. The use of graft polymers in the final rinse bath of a washing 
machine cycle has the advantage that the wash in the next wash cycle is 
substantially less soiled by detached dirt particles present in the wash 
liquor than without the addition of the grayness inhibitor in the 
preceding wash. 
In the Examples, the parts and percentages are by weight. The K values of 
the graft polymers were determined according to H. Fikentscher, 
Cellulosechemie, 13 (1932), 58-64, 71-74, in a polymer concentration of 2% 
strength by weight in dimethylformamide at 25.degree. C.; K is here 
k.10.sup.3. The Fikentscher K-value is an art recognized and accepted 
indication of relative molecular weights of polymers and is described in, 
"Vinyl and Related Polymers" by Schidlkneckt, John Wiley and Sons, New 
York 11, N.Y., 1952, at page 676. The number average moleculr weights of 
the polyalkylene oxides (a) used were calculated from the OH number. 
The following products were used: graft polymers 1 to 16 
The graft polymers were prepared using the process disclosed in GB Pat. No. 
922,457 by grafting the monomers (b) indicated in Table 1 onto 100 parts 
of a polyalkylene oxide having the number average molecular weight 
likewise indicated in Table 1. The K values of the graft polymers are 
likewise given in Table 1. 
TABLE 1 
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Graft 
poly- Weight ratio 
Mn of 
mer Monomer PEO/monomer PEO used 
K-value 
______________________________________ 
1 VPr 1:0.5 300 9.1 
2 VPr 1:2.0 300 12.4 
3 VPr 1:2.0 9,000 32.3 
4 VPr 1:1.72 35,000 57.9 
5 VPr 1:2.3 35,000 53.8 
6 VPr 1:3.44 35,000 56.0 
7 VPr 1:4.0 35,000 40.5 
8 MA 1:2.0 300 16.1 
9* VPr 1:1.72 35,000 62.9 
10 VAc/VPr (8:2) 
1:2.0 6,000 28.5 
11 VAc/VPr (1:1) 
1:2.0 6,000 25.3 
12 VAc/VPr (7:3) 
1:2.0 9,000 39.0 
13 VAc/VPr (9:1) 
1:1.75 6,000 27.3 
14 VAc/VPr (9:1) 
1:1.75 9,000 40.9 
15 VAc/MA (8:2) 
1:2.0 9,000 39.8 
16 VAc/MA (9:1) 
1:2.0 6,000 26.5 
______________________________________ 
VPr = vinyl propionate 
VAc = vinyl acetate 
MA = methyl acrylate 
PEO = polyethylene oxide 
Mn = number average molecular weight 
*corresponds to graft polymer 4 hydrolyzed to 15 mole % 
The grayness-inhibiting action of the graft polymers indicated above was 
tested as follows: polyester test fabrics and polyester/cotton blend 
fabrics were subjected to a series of 3 washes together with a standard 
soil cloth. The soil cloth is renewed after every wash, the test fabric 
becoming more soiled in every wash. The whiteness of the test fabric after 
the third wash is used to assess the degree of soiling. Confidence in the 
results is increased by multiple replication and averaging. Photometric 
measurement of the reflectance in % was carried out in the present case at 
a wavelength of 460 nm (barium primary white standard as laid down in 
German Standard Specification DIN 5,033) on an Elrepho 2000 (Datacolor). 
______________________________________ 
Test conditions: 
Test equipment: Launder-O-meter 
Water hardness: 3.5 mmol of Ca/l, 
Ca:Mg = 3:2 
Liquor quantity: 250 ml 
Liquor ratio: 10:1 
Test temperature: 35 to 60.degree. C. 
Test duration: 30 minutes (with heating- 
up time) 
Detergent concentration: 
8 g/l 
______________________________________ 
In the Examples, the grayness inhibitor was always used in an amount of 
0.5%, based on the test detergent. The test vessels each contain 15 g of 
test fabric (5 g of polyester, 5 g of polyester/cotton blend and 5 g of 
cotton fabric) and 10 g of soil cloth. The soil cloth used was cotton soil 
cloth from the Krefeld laundry research station, specifically WFK 10D. 
The test detergent used had the following composition: 
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C.sub.12 -alkylbenzenesulfonate 
6.25% 
Tallow fat alcohol reacted with 
4.7% 
11 ethylene oxide 
Soap 2.8% 
Na triphosphate (90% retention) 
20% 
Na perborate (tetrahydrate) 
20% 
Na.sub.2 SO.sub.4 24% 
Sodium disilicate 6% 
Mg silicate 1.25% 
Carboxymethylcellulose (CMC), Na salt 
0.6% 
Tetrasodium salt of ethylenediamine- 
acetic acid 0.2% 
Remainder water ad 100%. 
______________________________________ 
The test detergent is thus a phosphate-reduced detergent of the type 
commercially available since the second stage of the provisions of the 
West German Detergents Act concerning the maximum quantity of phosphate 
came into force in January 1984. 
Table 2 shows the increase in the reflectance of polyester and 
polyester/cotton blend fabrics after addition of 0.5% of the products to 
be used according to the invention, based on the weight of test detergent 
used. Table 2 also shows the results of comparative examples. 
TABLE 2 
______________________________________ 
Example Addition % reflectance 
No. 0.5% based on test detergent 
PES PES/Co 
______________________________________ 
1 Graft polymer 1 57.3 63.6 
2 Graft polymer 2 56.8 62.7 
3 Graft polymer 3 62.7 62.5 
4 Graft polymer 4 62.3 64.9 
5 Graft polymer 5 59.3 62.3 
6 Graft polymer 6 57.3 62.7 
7 Graft polymer 7 58.5 62.7 
8 Graft polymer 8 64.4 63.1 
9 Graft polymer 9 61.5 62.9 
10 Graft polymer 10 66.7 66.3 
11 Graft polymer 11 64.1 65.5 
12 Graft polymer 12 65.8 66.1 
13 Graft polymer 13 68.7 69.2 
14 Graft polymer 14 70.1 69.4 
15 Graft polymer 15 68.8 69.4 
16 Graft polymer 16 69.1 68.3 
Comparative Examples 
1 -- 44.8 61.2 
2 VAc/VP/DEAEA copolymer .sup.1) 
55.3 61.7 
as per Ex. 8 of U.S. Pat. 
3,333,561 
3 PEO (Mn = 300) 42.0 56.1 
4 PEO (Mn = 9,000) 42.5 58.6 
5 PEO (Mn = 35,000) 43.9 59.9 
6 Dispersed polyvinyl 41.8 55.6 
propionate (K value: 51.7) 
7 Dispersed polymethyl acrylate 
42.5 58.8 
(K value: 62.3) 
8 Dispersed polyvinyl acetate 
44.2 50.3 
(K value: 42.0) 
______________________________________ 
VP = vinyl pyrrolidone 
DEAEA = dimethylaminoethyl acrylate 
VAc = vinyl acetate 
Mn = number average molecular weight 
As Table 2 reveals, the graft copolymers to be used according to the 
invention have a better action as grayness inhibitors than the copolymer 
give in Example 8 of U.S. Pat. No. 4,444,561. The Comparative Examples 
clearly show that neither dispersed polyvinyl propionate, nor dispersed 
polyvinyl acetate, nor dispersed polymethyl methacrylate nor, 
alternatively, polyethylene oxide alone have any grayness-inhibiting 
action.