A polyamide fibrous substrate having deposited on it an amount of a composition effective to impart stain-resistance comprising a water-soluble or water-dispersible alpha-olefin/maleic anhydride polymer or a mixture of said polymers, and processes for preparing the substrates. The maleic anhydride polymer is used either in hydrolyzed form or in the form resulting from reacting it with a lower alkyl alcohol so as to form an alpha-olefin/maleic acid monalkyl ester polymer.

FIELD OF THE INVENTION 
The present invention relates to polyamide textile substrates treated with 
stain-resistant compositions comprising water-soluble or water-dispersible 
maleic anhydride/alpha-olefin polymers, and processes for their synthesis. 
The substrates of this invention possess stain-resistance but do not 
suffer from yellowing to the extent that some previously known materials 
do. 
BACKGROUND OF THE INVENTION 
Polyamide substrates, such as nylon carpeting, upholstery fabric and the 
like, are subject to staining by a variety of agents, e.g., foods and 
beverages. An especially troublesome staining agent is FD&C Red Dye No. 
40, commonly found in soft drink preparations. Different types of 
treatments have been proposed to deal with staining problems. One approach 
is to apply a highly fluorinated polymer to the substrate. Another is to 
use a composition containing a sulfonated phenol-formaldehyde condensation 
product. 
For example, Liss et al., in U.S. Pat. No. 4,963,409, disclose 
stain-resistant synthetic polyamide textile substrates having deposited on 
them sulfonated phenol-formaldehyde polymeric condensation products. 
However, sulfonated phenol-formaldehyde condensation products are 
themselves subject to discoloration; commonly they turn yellow. Yellowing 
problems are described by W. H. Hemmpel in a Mar. 19, 1982 article in 
America's Textiles, entitled Reversible Yellowing Not Finisher's Fault. 
Hemmpel attributes yellowing to exposure of a phenol-based finish to 
nitrogen oxides and/or ultraviolet radiation. To deal with the yellowing 
problems, the condensation products were modified by Liss et al. by 
acylation or etherification of some of the phenolic hydroxyls. In a 
preferred embodiment disclosed by Liss et al., the modified condensation 
products were dissolved in a hydroxy-containing solvent, such as ethylene 
glycol prior to there being applied to the textile substrate. 
Allen et al., in U.S. Pat. No. 3,835,071, disclose rug shampoo compositions 
which upon drying leave very brittle, non-tacky residues which are easily 
removed when dry. The compositions comprise water-soluble metal, ammonium 
or amine salt of a styrene-maleic anhydride copolymer, or its half ester, 
and a detergent. Water-soluble metal salts of Group II and the alkali 
metals (particularly magnesium and sodium) are preferred and ammonium 
salts are most preferred by Allen et at. 
On the other hand, Fitzgerald et at., in U.S. patent application Ser. No. 
07/502819, filed 2 Apr. 1990, disclose the usefulness of aqueous solutions 
of hydrolyzed vinylaromatic/maleic anhydride copolymers in the treatment 
of textiles to render them resistant to staining. The preferred copolymer 
of Fitzgerald et al. is a hydrolyzed styrene/maleic anhydride copolymer. 
Fitzgerald et al. disclose that the monoalkyl ester of their maleic 
anhydride/vinyl aromatic polymer was ineffective as a stain-resist. 
Maleic anhydride/alphaolefin polymers are known. U.S. Reissue Patent No. 
28,475 discloses copolymerization of maleic anhydride and 1-olefins, such 
as, 1-hexene, 1-tetradecene and 1-octadecene. European Patent Application 
No. 306.992 published 15 Mar. 1989 discloses maleic anhydride/-1-alkene 
Terpolymerization of Maleic Anhydride With Vinyl Monomers, J. Polymer 
SGI., Part A: Polym. Chem., 27 (12), 4099-108, disclose terpolymers of 
maleic anhydride with (i) 1-hexene, propylene, isobutylene, styrene, 
isoprene or 1,3-butadiene, and (ii) methyl methacrylate, methyl acrylate 
or acrylonitrile. 
BRIEF SUMMARY OF THE INVENTION 
The present invention provides polyamide fibrous substrates treated with 
water-soluble or water-dispersible maleic anhydride/alpha-olefin polymers 
so as to impart stain-resistance to the substrates, and methods for 
preparing the same. Commonly, prior are materials known to be useful as 
stain-blockers were sulfonated phenol-formaldehyde condensates (excepting 
those of Fitzgerald et at., supra). Finding a non-sulfonated material, 
such as the water-soluble or water-dispersible alpha-olefin/maleic 
anhydride polymers of this invention, to be useful for this purpose was 
unexpected. 
DETAILED DESCRIPTION OF THE INVENTION 
The present invention relates to the use of water-soluble or 
water-dispersible maleic anhydride/alpha-olefin polymers, or mixtures of 
the same, as stain-resists for fibrous polyamides. A variety of linear and 
branched chain alpha-olefins can be used for the purposes of this 
invention. Particularly useful alpha-olefins are 1-alkenes containing 4 to 
12 carbon atoms, preferably C.sub.4-10, such as isobutylene, 1-butene, 
1-hexene, 1-octene, 1-decene, and dodecene, with isobutylene and 1-octene 
being preferred and 1-octene being most preferred. A part of the 
alpha-olefins can be replaced by other monomers, with isobutylene being 
most preferred. A part of the alpha-olefins can be replaced by other 
monomers, e.g. up to 50 wt % of alkyl(C.sub.1-4) acrylates, 
alkyl(C.sub.1-4) methacrylates, vinyl acetate, vinyl chloride, vinylidine 
chloride, vinyl sulfides, N-vinyl pyrrolidone, acrylonitrile, acrylamide, 
as well as mixtures of the same. 
In accordance with the present invention, it has been unexpectedly found 
that water-soluble or water-dispersible interpolymers (i.e. copolymers, 
terpolymers, and the like) of maleic anhydride and one or more 1-alkenes 
having 4 to 12 carbon atoms, particularly isobutylene and 1-octene, impart 
excellent stain-resistance to polyamide substrates (e.g. carpeting) at low 
pH. Copolymers of maleic anhydride with butadiene, ethylene, propylene or 
a 1-alkene containing having 14 to 24 carbon atoms were found by the 
inventor to be unsatisfactory for commercial purposes as stain-resists on 
such substrates. 
A part of the maleic anhydride (up to 30 weight %) can be replaced by 
acrylic or methacrylic acid. In another embodiment, a part (1-75%) of the 
maleic anhydride can be replaced by maleimide, N-alkyl(C.sub.1-4) 
maleimides, N-phenyl-maleimide, fumaric acid, crotonic acid, cinnamic 
acid, alkyl(C.sub.1-18) esters of the foregoing acids, 
cycloalkyl(C.sub.3-8) esters of the foregoing acids, sulfated castor oil, 
or the like. At least 95 wt % of the maleic anhydride co- or terpolymers 
having a number average molecular weight of in the range between about 700 
and 200,000, preferably between about 1000 and 100,000. 
The maleic anhydride polymers useful in the present invention can be 
prepared according to methods well-known in the art. The maleic anhydride 
polymers thus obtained can be hydrolyzed to the free acid or their salts 
by reaction with water or alkali, or they can also be reacted with 
C.sub.1-4 alkyl alcohol to provide polymeric alpha-olefin/maleic acid 
monoesters, which have stainblocking properties. Generally, the hydrolyzed 
maleic anhydride polymer, or the monoester polymer, should be sufficient 
water-soluble that uniform application to a fibrous polyamide surface can 
be achieved at an appropriate acidity. However, applications using water 
dispersions of the polymer mixed with a suitable surfactant may be used to 
impart stain-resistance. 
One can blend the stain-resists of the present invention with other known 
stain-resists, such as phenol-formaldehyde condensation products as 
disclosed in U.S. Pat. Nos. 4,833,009 and 4,965,325; methacrylic acid 
polymers disclosed in U.S. Pat. No. 4,937,123; or hydrolyzed polymers of 
maleic anhydride and one or more ethylenically unsaturated aromatic 
compounds described by Fitzgerald et al., supra. 
The polymers suitable for the purposes of this invention contain between 
about 0.4 and 1.3 polymer units derived from one or more olefin monomers 
per polymer unit derived from maleic anhydride. The alpha-olefin content 
of the polymers of this invention comprise between (a) 100 and 80 mol % of 
at least one 1-alkene containing 4 to 12 carbon atoms and (b) 0 to 20 mol 
% of at least one 1-alkene containing 3, or 14 to 24, carbon atoms. 
Polymers containing about one polymer unit derived from one or more olefin 
monomers per polymer unit derived from maleic anhydride are most effective 
in imparting stain resistance to textile substrates. The molecular weight 
of the polymers useful in the invention does not appear to be a limitation 
so long as the polymers are water-soluble or water-dispersible. Thus, for 
example, hydrolyzed isobutylene/maleic anhydride copolymers having number 
average molecular weights between about 6000 and 100,000 impart good 
stain-resistance to polyamide substrates. Even at a pH as low as 1.5, 
water-soluble isobutylene/maleic anhydride copolymers having number 
average molecular weights between about 6000 and 100,000 remained in 
solution in water at 60.degree. C. 
The polymers suitable for the purposes of this invention can be prepared by 
hydrolyzing the maleic anhydride/olefin polymers according to methods 
well-known in the art. For example, they can be hydrolyzed to the free 
acid or their salts by reaction with water of alkali. Generally, the 
maleic anhydride polymer should be sufficiently water-soluble that uniform 
application to a fiber surface can be achieved at an appropriate acidity. 
However, applications using dispersions of the polymers with suitable 
surfactants may be used to impart stain-resistance. 
Suitable maleic anhydride polymers can be conveniently obtained by 
hydrolysis of "Isobam"-01, an isobutylene maleic anhydride copolymer of 
molecular weight around 10,000, "Isobam"-04 a similar polymer having a 
molecular weight of around 40,000 or "Isobam"-10 a similar polymer having 
a molecular weight of around 100,000 with sodium hydroxide. Other suitable 
maleic anhydride polymers include BM-30 available from Kuraray Co. 
(Japan). BM-30 is an isobutylene/maleic anhydride/N-phenylmaleimide 
terpolymer having a molecular weight of around 40,000. Other suitable 
copolymers include monoesters of C.sub.4-12 alpha-olefin/maleic anhydride 
copolymers. The monoesters can be obtained by a range of reactions well 
known to those skilled in the art. A preferred method is by reaction with 
an alcohol by heating under reflux with the alcohol and then removing 
excess alcohol. Preferred alcohols are C.sub.1-4 alcohols, especially 
methanol and ethanol. 
Preparation of maleic anhydride/alpha-olefin polymers is also described in 
U.S. Reissue Patent No. 28,475, in EP 306992 and by Florjanczyk et at. in 
J. Polymer SCI., Part A, Polymer Chem., 27 (12) pages 4099 to 4108, the 
disclosure of which is specifically incorporated by reference. These 
references contain further teaching of techniques for the preparation of 
such polymers. 
The olefin/maleic anhydride polymers of this invention can be used as such 
in treating polyamide textile substrates. They can be effectively applied 
to polyamide fibrous substrates by a wide variety of methods known to 
those skilled in the art, such as: 
padding, 
spraying, 
foaming in conjunction with foaming agents, 
batch exhaust in beck dyeing equipment, or 
continuous exhaust during a continuous dyeing operation. They can be 
applied by such methods to dyed or undyed polyamide textile substrates. In 
addition, they can be applied to such substrates in the absence or 
presence of a polyfluoroorganic oil-, water-, and/or soil-repellent 
materials. In the alternative, such a polyfluoroorganic material can be 
applied to the textile substrate before or after application of the 
polymers of this invention thereto. 
The quantifies of the polymers of this invention which are applied to the 
textile substrate are amounts effective in imparting stain-resistance to 
the substrate. Those amounts can be varied widely; in general, one can use 
between 1 and 5% by weight of them based on the weight of the textile 
substrate, usually 2.5% by weight or less. The polymers can be applied, as 
is common in the art, at pHs ranging between about 2 an d7. However, more 
effective exhaust deposition can be obtained at a pH as low as 1.5. When 
the latter low pH is used, the preferred level of application to the 
textile substrate is about 2.5% by weight, based on the weight of the 
textile substrate. In an embodiment, a pH between about 2 and 3 is used. 
More effective stainblocking is obtained if the polymers are applied to 
the textile substrate at either 20.degree. C. followed by heat treatment 
at a temperature in the range between about 50.degree. and 150.degree. C. 
for about 1 to 60 minutes, or applied at temperatures in the range between 
about 40.degree. and 95.degree. C. for about 1 to 60 minutes. For example, 
at a pH between about 2 and 3, a temperature between about 70.degree. and 
90.degree. C. is preferred. However, stain-blocking can be obtained when 
application is effected even at that of cold tap water 
(10.degree.-15.degree. C.). 
The polymers of this invention can also be applied in-place to polyamide 
carpeting which has already been installed in a dwelling place, office or 
other locale. They can be applied as a simple aqueous preparation or in 
the form of aqueous shampoo preparation, with or without one or more 
polyfluoroorganic oil-, water-, and/or soil-repellent materials. They may 
be applied at the levels described above, at temperatures described, and 
at a pH between about 1 and 12, preferably between about 2 and 9. 
The following Examples are given to illustrate the invention not limit it. 
Unless otherwise indicated, all parts and percentages are by weight and 
temperature sin the Examples and Tests are in degrees Celsius. In the 
examples that follow, stain resistance was measured by the technique 
described below.

EXAMPLE 1 
An isobutylene/maleic anhydride copolymer (10g) having a number average 
molecular weight (GPC) of 32,600 and an MW/M.sub.n of 2.96, commercially 
available from Kuraray Co. (Japan) as "Isobam"-04, was hydrolyzed to a 10 
wt% solution in accordance. A 1% aqueous solution of the resulting 
isobutylene/maleic acid copolymer remained dear down to pH 1.5 at 
60.degree. C. 
EXAMPLE 2 
An isobutylene/maleic anhydride copolymer (10g) having a number average 
molecular weight (GPC) of 91,400 and an MW/M.sub.n of 2.86, commercially 
available from Kuraray Co. (Japan) as "Isobam"-10, was hydrolyzed to a 10 
wt% solution in accordance. A 1% aqueous solution of the resulting 
water-soluble maleic anhydride/isobutylene copolymer at 60.degree. C. 
became cloudy at pH 1.6. 
EXAMPLE 3 
An isobutylene/maleic anhydride/N-phenylmaleimide terpolymer (10g) having a 
molecular weight 40,000 (GPC), commercially available from Kuraray Co. 
(Japan) as BM-30 polymer, was hydrolyzed to a 10 wt % solution by. A 1% 
aqueous solution of the resulting water-soluble maleic 
anhydride/isobutylene/maleimide terpolymer at 60.degree. C. became cloudy 
at pH 2.5. 
EXAMPLE 4 
A solution of maleic anhydride (9.8g-0.1 mol) and 1-hexene (8.4g-0.1 mole) 
in propylene glycol methyl ether acetate (30g) was heated under agitation 
and nitrogen to 60 deg. C. A solution of 2.5 g of 75 wt % t-butyl 
peroxyneodecanoate in 6 g of propylene glycol methyl ether acetate was 
then injected into the reaction vessel within half hour via a syringe 
pump. The reactants were agitated for another hours at 60.degree. C. 
before being cooled to room temperature. The product was the poured into 
methanol which caused precipitation of a white solid which was filtered 
and air dried to give 10.5 g of a maleic anhydride/1-hexene copolymer. 
Hydrolysis was carried out by. 
EXAMPLE 5 
A solution of 9.8 g of maleic an_hydride (0.1 mole) and 11.2 g of 1-octene 
(0.1 mole) in 30 g of propylene glycol methyl ether acetate was heated 
under agitation and nitrogen to 95.degree. C. A solution of 2 g of t-butyl 
peroxy-2-ethylhexanoate in 6 g of propylene glycol methyl ether acetate 
was then injected into the reaction vessel within half hour via a syringe 
pump. The reactants were agitated for another hours at 95.degree. C. 
before being cooled to room temperature. The product was then poured into 
methanol which caused precipitation of a white solid which was filtered 
and air-dried to give 12.7 g of a maleic acid/1-octene copolymer having a 
number average molecular weight by vapor phase osmometry (VPO) of 2800. 
The approximate composition of the copolymer by .sup.13 C NMR: 
1-octene/maleic anhydride=0.72/1.00. Hydrolysis was carried out by. A 1% 
aqueous solution of the resulting maleic acid/1-octene copolymer at 
60.degree. C. became cloudy at about pH 2.7. 
EXAMPLE 6 
The procedures for preparation and hydrolysis were similar to those of 
Example 5. 
Reactants: 9.8 g of maleic anhydride (0.1 mole) 
16.8 g 1-dodecene (0.1 mole). 
EXAMPLE 7 
An isobutylene/maleic anhydride copolymer (50 parts) having a number 
average molecular weight (GPC) of 32,000, commercially available from 
Kuraray Co. (Japan) as "Isobam"-04, was reacted under agitation with 
methanol (50 parts) at reflux temperature (about 65.degree. C.) for 23 
hours. Excess methanol was then removed at reduced pressure (20 mm Hg) at 
70.degree.-90.degree. C. to give the isobutylene/maleic acid monomethyl 
ester which was then dissolved at room temperature in dilute ammonium 
hydroxide (2.5 parts of ammonia in 356 parts of water) to give a 14.5 wt % 
solution. 
EVALUATION METHOD 
Nylon fiber was treated with 1.2 wt % or 2.4 wt % stain resist at a 
goods-to-liquor ratio of 1:32 at a pH of 2.0 or 2.35 for 45 minutes at 
80.degree. or 95.degree. C. The fiber was then washed, air-dried and 
exposed at room temperature to a dye solution consisting of 0.2 g of FD&C 
Red Dye No. 40 and 3.2 g of citric acid in 1 liter of deionized water at a 
goods-to-liquor ratio of 1:40. After approximately 65 hours, the dye 
adsorbed onto the fiber was determined at a wavelength of 498-502 am by 
comparing the absorbance with that of the Control. Thus a number of 90 
means of the dye is adsorbed, indicating little stain resistance to the 
dye. The lower the number, the better is the resistance to stain. The 
results of the evaluation are set forth in TABLE 1. 
TABLE 1 
______________________________________ 
% Dye Adsorbed 
At 80.degree. C. 
At 95.degree. C. 
EXAMPLE pH 2.0 pH 2.35 pH 2.35 
pH 2.35* 
______________________________________ 
1 2 3 3 
2 2 1 1 
3 2 3 1 
4 3 30 1 
5 4 2 1 
6 14 22 
7 6 39 12 
CONTROL** 89 89 
______________________________________ 
*Fiber treated with 2.4 wt % stain resist 
**No stainblocker