Field of the Invention The present invention relates to polymeric stain-resist compositions. 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 composition containing a sulfonated phenol-formaldehyde condensation product to the substrate. However, sulfonated phenolformaldehyde condensation products are themselves subject to discoloration; commonly they turn yellow. Yellowing problems are described by W. H. Hemmpel in a March 19, 1932 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 problem, the condensation products were modified by Liss et al. in U.S. Patent Number 4,963,409 by acylation or etherification of some of the phenolic hydroxyls. My U.S. Application Serial Number 07/809,843 filed December 18, 1991, of which this is a continuation-in-part, descloses and claims polyamide fibrous substrates treated with water-soluble or water-dispersible maleic anhydride/alpha-olefin polymers to make them stain resistant and methods for preparing them. Stain-resistant polyamide substrates treated with the compositions of this invention are disclosed and claimed in my copending application filed of even date herewith, Attorney Docket No. CH-2261. Brief Summary of the Invention

The present invention provides a composition useful for imparting stain resistance to a polyamide fibrous substrate comprising

(i) a water-soluble or water-dispersible alpha-olefin/maleic anhydride polymer or a mixture of said polymers ; and

(ii) a sulfonated phenol-formaldehyde condensation product, which is useful as a dye resist agent, a dye fixing agent, a dye reserving agent or an agent which improves the wet-fastness of dyeing on polyamide fibers.

The compositions of the present invention show enhanced durability to shampoo washing of polyamide substrates treated with the compositions. In addition, the invention provides stain resists which are more resistant to yellowing when exposed to UV light or NO _x gases than are the sulfonated phenol/formaldehyde condensates. At least some embodiments of the invention seek to provide a stain-resistant composition capable of imparting good stain resistance together with a low propensity to yellowing and having good substantive properties. A further problem associated with prior art compositions is that they have low solubility in water at the low pH preferably used to treat textile articles unless surfactant is used. At least some embodiments of the invention seek to provide a stain-resistant composition having a good water-solubility. Detailed Description of the Invention

The Blend The two components may be blended together in a wide range of relative proportions. For example, the weight ratio of maleic anhydride copolymer to resin may lie in the range of between about 95:5 and 5:95, preferably between about 90:10 and about 10:90, more preferably between about 60:4040:60. The pH of the blend is adjusted to the required pH preferably in the range about 1 to 3 more preferably 1.5 to 2.5 with acid. Surprisingly the stain-resistant compostion of the present invention remains clear at such low pH. This finding is advantageous since the stain-resistant compostion of this invention need not contain any surfactant to solubilize the active ingredient. If desired however, the composition may contain a surfactant. Higher pH in the range up to about pH 7 to 9 may be used as well.

The maleic anhydride/alpha-olefin polymer The polymers useful for the purposes of this invention comprise one or more water-soluble or water-dispersible hydrolyzed maleic anhydride polymers.

A variety of linear and branched chain alpha-olefins can be used for the purposes of this invention. Particularly useful alpha-olefins are dienes containing 4 to 18 carbon atoms, such as butadiene, chloroprene, isoprene, and 2- methyl-l,5-hexadiene; 1-alkenes containing 4 to 8 carbon atoms, such as isobutylene, 1-butene, 1-hexene, 1-octene, and the like, 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 (C1.4) acrylates, alkyl (Ci .4) methacrylates, vinyl sulfides, N- vinyl pyrrolidone, acrylonitrile, acrylamide, as well as mixture of the same.

A part (preferably 1-75% by weight) of the maleic anhydride can be replaced by maleimide. N-alkyl (Cj .4) maleimides, N-phenyl-maleimide, fumaric acid, itaconic acid, citraconic acid, aconitic acid, crotonic acid, cinnamic acid, alkyl (CJ-18) ^{es ers} of the foregoing acids, cycloalkyl (C3.8) esters of the foregoing acids, sulfated castor oil, or the like. At least 95 wt% of the maleic anhydride co- or terpolymers have a number average molecular weight of in the range between about 700 and 200,000, preferably between about 1,000 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 aqueous alkali, or they can also be reacted with C1.4 alkyl alcohol to provide polymeric alpha-olefin/maleic acid monoesters, which have stainblocking properties.

The polymers suitable for the purposes of this invention contain between about 0.7 and 1.3 polymer units derived from one ore more alpha-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 contaimng 4 to 8 carbon atoms, or terminally unsaturated diene containing 4 to 18 carbon atoms, and (b) 0 to 20 mol% of at least one 1- alkene containing 3, or 10 to 18, 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 copolymer having number average molecular weights between about 6,000 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 6,000 and 100,000 remained in solution in water at 60°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 or alkali.

Suitable maleic anhydride polymers can 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. A commercially available product usable without further treating is "Lindron" 10 (ex Lindau Chemical), a butadiene/maleic anhydride copolymer having a molecular weight of about 5,000 to 10,000. Other suitable copolymers include monoesters of C4.8 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 _j .g 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 efal. 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 sulfonated phenol-formaldehyde resin The sulfonated phenol-formaldehyde condensation products which can be used for the purposes of this invention include any sulfonated hydroxy aromatic-formaldehyde condensation products which have been described in the prior art as being useful as dye-resist agents or dye-fixing agents, in other words, dye-reserving agents or agents which improve wetfastness or dyeings on polyamide fibers. See for example U.S. 4,592,940, U.S. 4,591,591, U.S. 3,790,344 and GB 1,291,784, the disclosure of which is specifically incorporated herein by reference. Examples of commercially available condensation products suitable for the invention are MESITOL NBS, product of Bayer AG (a condensation product prepared from bis(4-hydroxyphenyl)-sulfone, formaldehyde, and phenol sulfonic acid; U.S. Patent No. 3,790,344), as well as 'Εrional" NW, a product of Ciba-Geigy Corp., (formed by condensing a mixture of naphthalene monosulfonic acid, bis(hydroxyphenyl) sulfone and formaldehyde; U.S. Patent Number 3,716,393) and 'Εrional" LY. The sulfonated hydroxyaromatic formaldehyde products sold as

"Stainfree" by Cybron Chemicals and "Algard" NS by Allied Colloid Co. are also suitable.

Application The stain-resistant composition 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. The stain-resist components of the present invention can be applied to the substrate separately or together as a blend. In the case of the present invention, stain- resistance of polyamide substrates is slightly better if the maleic anhydride/olefin polymer is applied to the polyamide substrate followed by the sulfonated phenol/formaldehyde condensate. On the other hand, carpet mills in general prefer to apply components of a stain-resist mixture together, and such would be expected with the composition of this invention.

The stain resistant compositions of this invention can be applied by the foregoing methods to dyed or undyed polyamide textile substrates. In addition, they can be applied to such substrates in the absence or presence of a polyfluoro- organic 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 compositions of this invention thereto.

More effective stainblocking is obtained if the stain-resistant compositions are applied to the textile substrate at either 20°C followed by heat treatment at a temperature in the range between about 50 to 150°C for about 1 to 60 minutes, or applied at temperatures in the range between about 40 and 95°C for about 1 to 60 minutes. For example, at a pH between about 2 and 3, a temperature between about 70 and 90°C is preferred. However, stain-blocking can be obtained when application is effected even at that of cold tap water (10-15°C).

The stain-resistant compositions of this invention can also be applied in situ to polyamide ca eting 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 polyfluoro- organic oil-, water-, and/or soil- repellent materials. They may be applied at the

levels described above, at temperature described, and at a pH between about 1 and 9, preferably between about 2 and 7.

In the Examples that follow, all viscosities were determined at room temperature about 20°C and all percentages are by weight, and the following application and testing procedures were used.

Method of Application A light blue dyed cut-pile carpet constructed from 70 oz/sq yd superba-set BCF nylon 66 is treated in a laboratory Beck apparatus for 20 minutes at 80°C (176°F) at a 20:1 liquor-to-goods ratio with a solution of a stain resist agent described in one of the examples of pH of 2.0 and in the presence of 2.0 g per liter of magnesium sulfate to give an application load of 0.8% owf. Based on active ingredients. The carpet was then rinsed under tap water, partially de-watered by squeezing and dried in an forced-air oven for about 20 minutes at 121°C (250°F). A commercially available latex composition (Textile Rubber Co. Calhoun, GA) was applied as to carpet backing adhesive, with a secondary polypropylene backing under the trade name Actionbac (AMOCO, Atlanta, GA).

Stain Test A carpet specimen (3x5 inch) was placed on a flat non-absorbent surface. 20 ml of a solution made from 45 g of cherry-flavored, sugar sweetened, commercially available dilutable soft drink containing FD&C Red Dye No. 40 and 500 ml of water was poured into a 2-inch diameter cylinder which was tightly placed over the specimen. The cylinder was removed after all the liquid had been absorbed. The stained carpet specimen was left undisturbed for 24 hours, after which it was rinsed thoroughly under cold tap water and squeezed dry. The specimens were visually inspected and the amount of color remaining in the stained area rated according to the following stain rating scale: 5 = no staining 4 = slight staining 3 = noticeable staining 2 = considerable staining

1 = heavy staining

In other words, a stain rating of 5 is excellent, showing outstanding stain resistance, whereas 1 is the worst rating comparable to an untreated control sample.

Shampoo Wash Durability Test A 3x5 inch carpet specimen was submerged for 5 minutes at room temperature in a detergent solution consisting of Duponol WAQE (1.5 g per liter) and adjusted with dilute sodium carbonate to a pH of 10 OJ. The specimen was then removed, rinsed thoroughly under tap water, de-watered by squeezing and air- dried. The dry carpet specimen was then tested according to the stain test described above.

UV Lightfastness Colorfastness to UV light was measured according to AATCC Test Method 16E-1987. The specimens were rated after exposure to 40 AATCC Fading

Units (AFU) with the Gray Scale for color change.

NO _x Lightfastness

Colorfastness to oxides of nitrogen was carried out according to AATCC Test Method 164-1987. At the end of 2 cycles the specimens were rated to the Gray Scale for color change.

Treatment in accordance with this invention lead to stain-resistant carpets. Furthermore, carpeting washed with shampoo after application of the stain-resists of this invention, but before staining, still possessed a high degree of stain- resistance. Example 1

To a solution of 649.5 g of sodium hydroxide in 5184 g of deionized water at 40°C was slowly added under agitation 2,500 g of an isobutylene-maleic anhydride copolymer of 10,000 molecular weight, commercially available as "Isobam" -01 from Kuraray Corp., Japan. The exotherm during hydrolysis reached 70-90°C. The reaction mass was held about 15-20 hours 80-85°C before cooling to

65°C. To the clear, amber solution was added under agitation 1457.5 g of a 30% sulfuric acid solution which lowered the pH to 2.65. After cooling to about 55°C, the amount of 1764.7 g of a sulfonated hydroxy-aromatic formaldehyde condensation product available from Ciba-Geigy Corp. as 'Εrional" LY was added under agitation to give 11764.8 g of a clear, brownish solution having an active ingredient content of about 25%, a pH of 2.61 and a viscosity of 286 Pa.s. Addition of 12% sulfamic acid solution to a 1% solution of Example 1 did not cause precipitation at a pH as low as 1.5.

Example 2 To a solution of 259.7 of sodium hydroxide in 2073.6 g of dionized water at 60°C was slowly added under agitation 1,000 g of an isobutylene-maleic

anhydride copolymer of molecular weight of about 40,000 and commercially available as "Isobam" -04 from Kuraray Corp., Japan. The reaction mass was agitated for 18 hours at 80-85°C. To this clear, amber liquid was then added at 60°C under stirring a solution of 683.3 g 30% sulfuric acid in 983.3 g deionized water to give a clear product having an active ingredient content of 20%, a viscosity of 606 Pa.s at a pH of 2.40. To 400 g of polymer prepared in the manner described above was added at room temperature and under agitation 80.0 g of a sulfonated hydroxyaromatic formaldehyde condensation product available from Ciba-Geigy Corp. as 'Εrional" LY. The clear brownish liquid had an active ingredient content of 20.8%. A 1% solution remained clear after adjusting the pH to 1.5 with dilute sulfuric acid.

Example 3 To a solution of 77.9 g of sodium hydroxide in 622.1 g deionized water at 40°C was slowly added 300 g of an isobutylene-maleic anhydride copolymer of 10,000 molecular weight, commercially available as "Isobam" -01 from Kuraray Corp., Japan. The exotherm during hydrolysis reached 70-90°C. The reaction mass was held for about 15 to 20 hours at 80-85°C. After cooling to 60°C a solution of 208.6 g 30% sulfuric acid in 80 g deionized water was added under agitation to give 1288.6 g of a clear, amber solution having 23.3% of active ingredients, a pH of 2.47 and a viscosity of 340 Pa.s. To 364.8 g polymer prepared in the manner described above was added to room temperature under agitation 50 g of a sulfonated hydroxyaromatic formaldehyde condensation product available from C bron Chemicals as "Stainfree'' (30% active ingredients) to give a clear brownish product having an active ingredient content of about 24.1%. This material remained clear when applied at a pH of 2.0 at any desired concentration.

Example 4 To 364.8 g of the polymer used in Example 3 was added under agitation at room temperature 50 g of a sulfonated hydroxyaromatic formaldehyde condensate available from Allied Colloid Co. as "Algard" NS (30% active ingredients) to give a clear brownish liquid having an active ingredient content of about 24.1%. This material remained clear at a pH of 2.0 at any desired concentration.

Example 5 To a solution of 26.0 g of sodium hydroxide in 207.4 g of deionized water was slowly added at 50°C under stirring 100 g of an isobutylene-maleic anhydride copolymer having a molecular weight of 10,000 and commercially

available as "Isobam"-01 from Kuraray Co., Japan. A solution of 58.8 g of a sulfonated hydroxyaromatic formaldehyde condensate available from Bayer AG. as "MESITOL" NBS (30% active ingredients) and 24.7 g of a 30% sodium hydroxide solution in 759.3 g of deionized water was added under stirring to give 1176.2 g of a clear, brownish liquid at a pH of 8.55 and an active ingredient content of 10.0%. A 1% solution remained clear after adjusting the pH to 2.0 with dilute sulfamic acid.