Pre-treating textiles with dispersions of graft polymers based on polyalkylene oxides to impart soil release properties thereto

A process for the pre-treatment of textile surfaces which impart soil release properties, comprising contacting a textile with a dispersion graft copolymer of: PA0 (a) a polyalkylene oxide which has a number average molecular weight of from 300 to 100,000, is based on ethylene oxide, propylene oxide and/or butylene oxide and may be capped at one end through etherification, esterification, amidation or reaction with a isocyanate, and PA0 (b) at least one vinyl ester derived from a saturated monocarboxylic acid containing 1 to 6 carbon atoms and/or a methyl or ethyl ester of acrylic or methacrylic acid in a weight ratio (a):(b) of from 1:0.2 to 1:10 in an aqueous liquor.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to the use of a dispersion of a graft 
copolymer based on a polyalkylene oxide as a pre-treatment for 
polyester/cotton and polyester fabric surfaces. The fabrics so treated 
exhibit improved dirty motor oil soil release properties when compared to 
fabrics which are not so treated. 
The present invention further relates to pre-treatment of cotton fabrics 
and polyester fibers, which fibers are pre-treated with a graft copolymer 
based on a polyalkylene oxide, and then woven into a fabric composition. 
The textile so woven and pre-treated exhibits improved oily soil release 
properties over fabrics which have not been treated before being woven 
into a textile. 
2. Description of the Prior Art 
Kud et al, U.S. Pat. No. 4,746,456 disclose detergents which contain added 
graft copolymers which have an antiredeposition action and are obtainable 
by grafting polyalkylene oxides with vinyl acetate or vinyl propionate. 
The detergents of Kud et al are useful for creating a wash liquor for the 
washing of textiles and which prevents soil from redepositing on clean 
textile surfaces. 
Williams et al, U.S. Pat. No. 3,563,795 disclose water soluble copolymers 
of maleic anhydride and vinyl acetate for use as soil release agents. 
Dickson et al, U.S. Pat. No. 3,798,169 disclose polycarboxylate polymers as 
soil release agents in a dilute solution in the presence of a polyvinyl 
metal salt. 
Dickson, U.S. Pat. No. 3,821,147 discloses compositions for imparting 
non-permanent soil release characteristics comprising an aqueous solution 
of polycarboxylate copolymer and a water soluble amine. 
Dickson, U.S. Pat. No. 3,836,496 discloses polycarboxylate copolymers and 
polyacrylamides for use as detergent compositions. 
Kakar et al, U.S. Pat. No. 4,007,305 disclose a method for imparting 
non-durable soil release and soil repellant properties to textile 
materials by treating the textile with a dissolved water soluble 
hydrophilic soil release polymer having carboxylic acid groups and a 
dispersed hydrophobic soil repellant fluoro chemical. 
SUMMARY OF THE INVENTION 
Fabrics woven from polyester fibers or consisting of blends of polyester 
and cotton fibers are often difficult to clean. Because polyester fibers 
are hydrophobic, they are difficult to wet in aqueous solution, and are 
relatively easy to stain with oily (lipophilic) soils. Textile 
manufacturers have addressed this problem by applying surface finishes to 
these fabrics. These surface coatings are often hydrophilic in nature and 
can enhance the wetting of the fabric by detergent solutions thus 
promoting the rollup of oily soils. In addition, the fiber coating can act 
as a barrier between the surface and the soil. 
Surface finishes can be applied to textiles in a variety of ways. Often, an 
aqueous bath is employed in the pre-treatment process with polymer 
concentrations ranging from 0.05-15% active. In some cases, a 
non-permanent coating can be deposited in the rinse cycle of a 
conventional laundry process. In instances where a more permanent finish 
is required, the overlayer can be "heat set" to the fabric by drying at 
elevated temperatures often with mechanical pressure on the textile. 
The present invention is a dispersion of a graft copolymer based on 
polyalkylene oxides which are used to pre-treat polyester/cotton and 
polyester fabric surfaces. The fabric surfaces so treated exhibit improved 
dirty oil soil release properties when compared to fabrics which are not 
pre-treated. 
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
It has been discovered that dispersions of a polyethylene oxide (PEO)/vinyl 
acetate graft copolymer in water (20%, or 5% active) impart dirty motor 
oil soil release properties to fabrics which contain polyester; single 
knit filament polyester, staple polyester and D(65)/C(35) blends. 
Significantly, it has also been observed that PEO/vinyl propionate graft 
copolymers impart a soil release finish at even lower concentrations (5% 
active) when applied to these fabrics from a (95%/5%) (ethanol/water) 
dispersion. 
It is an object of the present invention to provide polymeric additives for 
the pre-treatment of goods containing synthetic/natural fiber blends and 
synthetic fibers. We have found that this object is achieved, in 
accordance with the invention, by the use of graft copolymers which are 
obtainable by grafting 
(a) a polyalkylene oxide which has a number average molecular weight of 
from 300 to 100,000, is based on ethylene oxide, propylene oxide and/or 
butylene oxide and may be capped at at least one end, by etherification, 
esterification, amidation, or reaction with an isocyanate, with 
(b) at least one vinyl ester derived from a saturated monocarboxylic acid 
containing 1 to 6 carbon atoms and/or a methyl or ethyl ester of acrylic 
or methacrylic acid in a weight ratio (a):(b) of from 1:0.2 to 1:10 and 
whose grafted-on monomer (b) may optionally be hydrolyzed up to 15 mole 
percent. 
The products to be used according to the invention are known for example 
from GB Patent 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, are based on ethylene oxide, propylene oxide and/or 
butylene oxide and may be capped at at least one end. Preference is given 
to using homopolymers of ethylene oxide or ethylene oxide copolymers 
having an ethylene oxide content of from 40 to 99 mole percent. For the 
ethylene oxide polymers which are preferably used, the proportion of 
ethylene oxide present as copolymerized units is thus from 40 to 100 mole 
percent. Suitable comonomers for these copolymers are propylene oxide, 
n-butylene oxide and/or isobutylene oxide. Suitable copolymers are those 
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 percent, the propylene oxide content from 
1 to 60 mole percent and the butylene oxide content in the copolymers from 
1 to 30 mole percent. Aside from straight-chain, it is also possible to 
use branched homopolymers or copolymers which may be end group capped, at 
at least one end, as a graft base. Branched copolymers may be prepared by 
addition of ethylene oxide with or without propylene oxide and/or butylene 
oxides onto polyhydric, low molecular weight alcohols, such as, 
trimethylolpropane, glycerol, pentoses or hexoses and mixtures thereof. 
The alkylene oxide unit can be randomly distributed in the polymer or be 
present therein as blocks. One or more terminal OH groups of the 
polyalkylene oxides can be end group capped. This is to be understood as 
meaning that it may be etherified, esterified, aminated or modified by 
reaction with an isocyanate. 
In the case of etherification, suitable substituents for the terminal 
hydrogen atoms of the hydroxyl groups on the polyalkylene oxides are alkyl 
groups having 1 to 18 carbon atoms, substituted alkyl, such as benzyl, or 
even phenyl. Polyalkylene oxides whose end groups are esterified may be 
obtained by esterifying the above-described polyalkylene oxides with 
carboxylic acids of 1 to 18 carbon atoms, for example by reaction with 
formic acid, acetic acid, propionic acid, butyric acid, malonic acid, 
succinic acid, stearic acid, maleic acid, terephthalic acid or phthalic 
acid. If carboxylic anhydrides are available, the end group cap on the 
polyalkylene oxides can also be obtained by reaction with the 
corresponding anhydrides, such as maleic anhydride. The polyalkylene 
oxides can also be modified at at least one end by reaction with 
isocyanates, such as phenyl isocyanate, naphthyl isocyanate, methyl 
isocyanate, ethyl isocyanate or stearyl isocyanate and mixtures thereof. 
Aminated products are obtained by autoclave reaction of the corresponding 
alkylene oxide with amines such as C.sub.1 -C.sub.18 -alkylamines. 
Component (b) comprises vinyl esters derived from a saturated 
monocarboxylic acid containing 1 to 6 carbon atoms, and also methyl 
acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate and 
mixtures thereof. Suitable vinyl esters may be selected from the group 
consisting of vinyl formate, vinyl acetate, vinyl propionate, vinyl 
butyrate, vinyl valerate, vinyl i-valerate and vinyl caproate. Of the 
monomers of group (b), preference is given to using vinyl acetate, vinyl 
propionate, methyl acrylate, methyl methacrylate and mixtures thereof. 
The graft copolymers are prepared in a conventional manner, such as by 
grafting the polyalkylene oxides of component (a), which may be end group 
capped at at least one end, 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 component (a) 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 only a part, for example 10%, of the 
mixture of end group capped polyalkylene oxide to be polymerized, at least 
one monomer of group (b) and an 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 to completion. The weight 
ratio of components (a):(b) is from 1:0.2 to 1:10, preferably from 1:0.5 
to 1:6. 
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 mixtures thereof, redox initiators and azo starters and mixture 
thereof. 
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 superatmospheric pressure. If desired, the graft copolymerization 
described above can also be carried out in a solvent. Suitable solvents 
are, for example, alcohols, e.g. methanol, ethanol, n-propanol, 
isopropanol, n-butanol, sec-butanol, tert-butanol, n-hexanol and 
cyclohexanol and mixture thereof; 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 and mixtures thereof. 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, and can take on a 
dispersion character. To transfer any water-insoluble products which form 
during the polymerization into solution, it is possible to add organic 
solvents such as monohydric alcohols having 1 to 3 carbon atoms, acetone 
or dimethylformamide and mixtures thereof. 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, such as polyvinyl alcohol. 
The emulsifiers used may be selected from the group consisting of 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 polymer is from 
5 to 200, preferably from 10 to 100, parts by weight. 
The graft polymers have a K value of from 5 to 200, preferably from 5 to 50 
(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 optionally be subjected to a partial hydrolysis 
where up to 15 mole percent of the grafted-on monomers of component (b) 
are hydrolyzed. For instance, the hydrolysis of graft polymers prepared 
using vinyl acetate as preferred monomers of group (b) gives graft 
polymers containing vinyl alcohol units. The hydrolysis can be carried out 
by adding a base, such as a sodium hydroxide solution, potassium hydroxide 
solution, ammonia or amines, such as triethanolamine, morpholine or 
triethylamine, and mixtures thereof or alternatively, by adding acids, 
such as HCL, and if necessary, heating the mixture. 
The graft copolymers are useful as additives in the pre-treatment of goods 
containing synthetic and synthetic/natural fiber blends. Specifically, the 
textiles to be treated may be coated in a bath containing aqueous, or 
organic solvents, and employing polymer concentrations of from about 
0.05-15% active. The textile is immersed in the bath, and the polymer is 
deposited onto the fabric. The polymer may be heat set to the fabric by 
drying at a temperature of at least 100.degree. C.

The following examples are given to illustrate various aspects of the 
invention. Those skilled in the art recognize that they are not to be 
construed as limiting the scope and spirit of the invention. 
In the Examples, the following test methodology was used. 
Three fabric types (5 replicates of each) were soaked in a dispersion of 
the graft copolymer for 10 minutes at room temperature, removed from the 
bath and placed on a metal rack. The swatches were dried with a heat gun 
and placed between two pieces of aluminum foil. Each fabric was pressed 
with a clothes iron (setting=5; cotton) for two minutes on each side and 
allowed to cool. Three drops of dirty motor oil (obtained from a 1975 Ford 
Granada) were added to each swatch and the stain was allowed to wick 
overnight. Reflectance readings were taken with a Gardner colorimeter for 
each stained fabric (Rd.sub.2). The swatches were washed at 120.degree. F. 
in Wyandotte tap water using a Whirlpool Imperial washer (17 gallons). A 
ten minute cycle was employed and 1/4 cup of FRESH START laundry detergent 
was added to clean the swatches. The fabrics were dried for 30 minutes in 
a Whirlpool Imperial dryer and reflectance readings for the washed 
swatches (Rd.sub.3) were measured. Standard clean swatches were used to 
determine an initial reflectance value (Rd.sub. 1) for each fabric type. 
Percent soil release (% SR) was calculated using these three reflectance 
values (Rd.sub.1, Rd.sub.2 and Rd.sub.3) as follows: 
EQU (Rd.sub.3 -Rd.sub.2)/(Rd.sub.1 -Rd.sub.2).times.100=% SR 
where Rd.sub.1 =the reflectance of the virgin fabric 
Rd.sub.2 =the reflectance of the stained fabric 
Rd.sub.3 =the reflectance of the washed fabric 
In Table I, we show data obtained with fabrics that were pre-treated with a 
20% dispersion of SOKALAN.RTM. HP-22 (a PEO/vinyl acetate graft copolymer) 
in water. Least significant differences at 95% confidence are shown in 
parenthesis. As the table indicates, a 20% dispersion of SOKALAN.RTM. 
HP-22 in water provided significant soil release on cotton, staple 
polyester and D(65)/C(35) blend fabrics. A very high loading of polymer 
was required to achieve 100% SR on these fabrics, however. 
Additional experiments were carried out at lower dispersion concentrations 
(5% PEO/vinyl acetate). In this study, the PEO/vinyl acetate (PEO/VAc) 
graft was compared to a PEO/vinylpropionate (PEO/VPr) graft copolymer. The 
PEO/VPr graft was applied from a (95/5) (ethanol/water) dispersion. 
Results shown in Table II indicated better performance for the PEO/VPr 
graft than for the PEO/vinyl acetate on filament polyester, staple 
polyester, and D(65)/C(35) blend fabrics. 
Since both PEO/VAc and PEO/VPr impart soil release properties to polyester 
containing textiles, these copolymers could be used alone or in 
conjunction with other compounds to prevent oily stains from setting in. 
TABLE I 
______________________________________ 
Pre-treatment with a 20% 
Dispersion of PEO/Vinyl Acetate Graft Copolymer in Water 
Fabric Type 
Cotton Staple Poly. 
Blend 
(S-405) (S-767) (S-7435) 
______________________________________ 
20% PEO/vinyl 
86.8% (1.9%) 
98.1% (0.8%) 
98.1% (0.4%) 
acetate in Water 
No 33.8% (3.8%) 
5.1% (0.6%) 
10.6% (1.5%) 
Pre-treatment 
Advantage Over 
+53.0% +93.0% +87.5% 
The Control 
______________________________________ 
95% confidence intervals are shown in parenthesis. 
TABLE II 
______________________________________ 
Comparison of Pre-treatment with 
PEO/Vinyl Acetate and PEO/VPr Graft Copolymers 
Fabric Type 
Single Knit 
Staple Poly. 
D(65)/C(35) 
Poly. (S-730) 
(S-767) (S-7435) 
______________________________________ 
5% PEO/Vinyl 
37.0% (6.1%) 
16.6% (3.1%) 
55.0% (5.1%) 
Acetate in Water 
No 6.5% (1.3%) 
8.3% (0.5%) 
10.9% (8.3%) 
Pre-treatment 
Advantage Over 
+31.5% +8.3% +44.1% 
The Control 
PEO/VPr 5% 84.7% (3.5%) 
48.0% (3.9%) 
75.4% (6.4%) 
Active Disper. 
In 95/5 
EtOH/H.sub.2 O 
Advantage Over 
+78.2% +39.7% +64.5% 
The Control 
______________________________________ 
95% confidence intervals are shown in parenthesis.