WO1994002549A1

WO1994002549A1 - LOWERING THE pH OF TEXTILE PROCESSING SOLUTION WITH AN ACID/BASE SALT AS A pH ADJUSTING AGENT

Info

Publication number: WO1994002549A1
Application number: PCT/US1993/006995
Authority: WO
Inventors: Richard Sargent; Jeffrey R. Alender
Original assignee: Peach State Labs, Inc.
Priority date: 1992-07-24
Filing date: 1993-07-26
Publication date: 1994-02-03
Also published as: CA2140923A1; CA2140923C; US5234466A; AU5574894A; US5616151A

Abstract

A method for the adjustment of pH in textile processing solutions that includes the use of urea sulfate or other strong acid in the presence of a weak or strong base.

Description

LOWERING THE PH OF TEXTILE PROCESSING SOLUTION WITH AN ACID/BASE SALT AS A PH ADJUSTING AGENT

BACKGROUND OF THE INVENTION This application is in the area of methods for the adjustment of pH in textile processes.

Fibers are processed in a number of ways before incorporation into textile products such as fabric and carpet. In a typical procedure in the case of nylon, nylon chip is first extruded and then converted into either continuous filament or staple fiber. The filament or staple fiber is then spun into yarn, and twisted and heat set as desired. The undyed, untreated yarn can be dyed and finished before or after fabrication into a final product. The dying procedure can occur by batch or continuous operation. Again, in the case of nylon, in either operation, the dye bath typically includes an acid dye (i.e., a dye that adheres to the nylon under acidic conditions) , a chelating agent, an acid dye leveler (an agent that promotes the even absorption of dye by the yarn) , a wetting agent, and a pH adjuster (to insure acidic pH) . The dye bath for continuous processing is typically maintained at a pH of between 3 and 6.5, and more typically, between 4 and 5. The dye bath for exhaust application is typically maintained at a pH of between 6 and 7, and more typically at pH 6.5. The dyed yarn is then taken through a fixing step (usually moist heat) , and rinsed. The dyed yarn is finished by the application of desired finishing chemicals to the yarn, including stain blocking agents, fluorochemicals, fabric softeners, stabilizers, UV absorbers, optical brighteners, sewing assist agents, antistatic agents, waterproofing agents, durable resins, starches, and sizes. Some of these agents adhere more effectively when applied under acidic conditions. For example, common commercial stain blocking chemicals such as BASF Stain Protector and DuPont Stain resist chemicals are usually more effective when applied at a pH of between 1.9 and 2.5.

Fluorochemical polymeric finishes are usually applied at a pH of between 4 and 5. Coapplication of a stain blocking agent and a fluorochemical in a foam is often carried out at a pH of 3-5.

Yarns and fibers made from materials other than nylon can also be dyed or treated under acidic conditions. Wool and silk are typically acid dyed. Polyester is often disperse dyed with a solution that may have an acidic pH.

Traditional chemicals used for pH adjustment in textile processing include sulfamic acid, formic acid, sulfuric acid, phosphoric acid and combinations thereof. These pH adjusters can exhibit one or a combination of low efficiency (i.e., require large amounts of chemical for the desired effect) , high cost, difficulty in handling, hazards in handling, corrosiveness, or high acidity of the resulting effluent stream.

One of the most commonly used pH adjustment system used in carpet processing is sulfamic acid ( (HO) S(0)₂NH₂) . Lower pHs can be attained with sulfamic acid than with comparable amounts of formic acid. Sulfuric and phosphoric acids will lower pH more efficiently than either sulfamic or formic acids. Corrosivity tests performed on carbon steel and stainless steel coupons show that all of these acids can be harmful to metal equipment.

Sulfamic acid is a solid that can be dissolved in water up to a concentration of about 15% at room temperature. Dissolving the acid is cumbersome and represents an additional step in the textile manufacturing processes while creating another quality control step. Since sulfamic acid is only soluble in water to an extent of about 15% by weight at room temperature, and is usually used in a 13% solids solution, it is not a very efficient pH adjustment system. Approximately 6-14 grams/liter of 13% sulfamic acid solution is required to lower the pH of a typical stain resist application bath to a pH of 2 , depending on the concentration and type of stain blocking chemical used. While sulfamic acid is weaker than sulfuric acid, sulfamic acid powder can cause burns and thus requires special procedures for handling. Sulfamic acid solution is also quite corrosive, and thus has a damaging effect on machinery, structural supports and concrete. Sulfamic acid solution even corrodes 316 stainless steel coupons and carbon steel.

The use of sulfamic acid increases the cost of textile processes because of the time and expense incurred to dissolve the powder, and the cost involved to repair and maintain corroded equipment. Further, as a significant amount of the acid used is carried into the effluent stream, the effluent must be neutralized to a significant extent with caustic prior to discharge to the water treatment facility, further adding to the cost of the textile process.

The object of the present invention is to provide a method for pH adjustment in textile processing that includes the utilization of a chemical that exhibits one or more of the properties of convenience, low corrosivity, efficiency of use, and minimal adverse impact on the environment. SUMMARY OF THE INVENTION

In one embodiment, the invention as disclosed is a method for adjusting pH during textile processing that includes the addition of urea sulfate to the aqueous textile processing solution. Urea sulfate can be formed with any desired ratio of urea and sulfuric acid that performs the desired function. Examples of suitable salts include those formed by combining between 1:4 and 4:1 moles of urea with sulfuric acid, more usually between 2.5 and 0.25 moles of urea with one mole of sulfuric acid, or between 2.0 and 0.5 moles of urea to sulfuric acid. A preferred ratio is approximately 1 mole of sulfuric acid to one mole of urea, or alternatively, a slight molar excess of urea.

The use of urea sulfate to adjust pH in textile processing solutions has advantages over conventional methods of pH adjustment in textile processing. Urea sulfate is less corrosive to metal equipment and other contact surfaces when heated than the equivalent amount of sulfamic acid. Further, urea sulfate may decompose under heat or catalytic conditions (including acidic pH) to carbon dioxide and ammonium sulfate. These decomposition products have a decreased tendency to lower the pH of effluent streams, and are less corrosive than traditional chemicals used for pH adjustment in textile processing.

In an alternative embodiment, the invention includes the use of a salt formed from a strong acid and a weak base as the pH adjusting agent. Preferred salts are those that, like urea sulfate, efficiently lower the pH of textile processing baths but exhibit less corrosivity when heated than the strong acid alone, and therefore, are less harmful to persons and equipment with which it is in contact. In another embodiment, a pH adjusting agent for textile processes is provided that is the salt of a strong acid and a strong base. Mixtures of the pH adjusting agents can also be used. Urea sulfate, as well as the equivalent strong acid/weak base salts disclosed herein, can be used in any process that sulfamic acid or like acids have traditionally been used in, including but not limited to sulfation, metal cleaning, scale removal, manufacture of dyes and pigments for the removal of excessive nitrite from diazotization reactions, in paper manufacturing by reducing pulp degradation in the bleaching stages of electroplating, and as a catalyst in urea- formaldehyde resin manufacturing. Urea sulfate can also replace traditional acids for solvation, in aqueous cleaning solutions, and in processing solutions not related to textile processing. Materials that can be cleaned include metals, jewelry, printed circuit boards, wood, masonry, mortar, concrete, painted surfaces, plastics, polymeric substances, and the like.

DETAILED DESCRIPTION OF THE INVENTION

The term alkyl, as used herein, unless otherwise specified, refers to a saturated straight, branched, or cyclic hydrocarbon of C. to

Cio-

The term aryl, as used herein, refers to phenyl and substituted phenyl, wherein the substituent is alkyl, halo (chloro, bromo, iodo, or chloro) , hydroxy, sulfonyl, carboxylic acid, nitro, or a combination of these, and wherein the aromatic ring can have up to three substituents. The term textile processing solution as used herein refers to any aqueous solution that is used during the processing of fiber, yarn, or textile products, including carpets, carpet tile, and fabric, to treat the fiber, yarn, or textile product to improve its properties. Nonlimiting examples of textile processing solutions include dyebath solutions and finishing solutions, including those that apply stain blocking chemicals to the fiber, yarn, or textile product. The fiber, yarn, or textile product can be prepared from any material, including nylon (polyamide) , wool, silk, polyester, acrylics, modacrylics, polyolefins, and cellulosics, including rayon and cotton.

The term stain blocking agent, as used herein, refers to a chemical that imparts stain resistance to the fiber, yarn, or product. Nonlimiting examples of chemicals that impart stain resistance to nylon fibers are described in U.S. Patent No. 4,501,591 to Ucci, et al., U.S. Patent Nos. 4,592,940 and 4,680,212 to Blythe, et al., U.S. Patent No. 4,780,099 to Greschler, et al., U.S. Patent No. 4,822,373 to Olson et al., European Patent Application 87301180.3 by E.I. Du Pont Nemours & Co., U.S. Patent No. 4,937,123 to Chang et al., and U.S. Patent No. 4,940,757 and U.S. Patent No. 5,061,763 to Moss, et al..

The term polyamine, as used herein, refers to a monomer or polymer that has more than one -NH₂, - NH(alkyl), -N(alkyl)₂, -NH(hydroxyalkyl) , -N(hydroxyalkyl)₂, -NH(aryl), or -N(aryl), attached to the monomer or polymer. The invention as disclosed is a method to adjust pH in textile processing solutions that includes the use of urea sulfate or its equivalent in the processing solution. In particular, urea sulfate can be added to textile dye baths and to finishing solutions to adjust pH in a manner that is often less harmful to the equipment that it is in contact with than traditional pH adjusters used in textile processing.

It is known that urea decomposes when heated or under certain catalytic conditions to ammonia and C0₂. Although not confirmed, it is hypothesized that the application of heat to a processing solution that includes urea sulfate results in the decomposition of the salt to carbon dioxide and the ammonium salt of sulfuric acid (urea sulfate) . This decomposition process may result in an effluent that is less acidic, and thus less hazardous to the environment, than effluent containing traditional pH adjusters.

Since effluent resulting from textile processing that utilizes urea sulfate as the pH adjuster may have a higher pH than comparable effluent from textile processing activities using traditional pH adjusters, the effluent requires less neutralization before discharge to the waste water treatment system.

Urea sulfate can also replace traditional acids for solvation, in aqueous cleaning solutions, and in processing solutions not related to textile processing. Materials that can be cleaned include metals, jewelry, printed circuit boards, wood, masonry, mortar, concrete, painted surfaces, plastics, polymeric substances, and the like.

Preparation of Urea Sulfate

Urea is weakly basic, forming salts with strong acids. Urea sulfate is a salt formed from the simple mixture of urea with sulfuric acid. Common urea sulfate salts include the 1:1 urea to sulfuric acid salt (CAS 21351-39-3), and the 2:1 urea to sulfuric acid salt (CAS 17103-31-0). The 2:1 urea sulfuric acid salt is sold by Aldrich Chemical Company. Any desired ratio of urea to sulfuric acid that performs the desired function in a textile processing solution can be prepared by simply mixing the appropriate ratios of components, typically in water. The mixing of urea with sulfuric acid typically results in an exotherm that should be handled with care.

The preferred composition is a solution of sulfuric acid and urea combined in a 1:1 molar ratio or a slight excess of urea, in water. This composition results in a sulfuric acid urea salt solution that has the pH reduction ability of sulfuric acid when used, for example, to reduce the pH of stain resist application baths, but is less corrosive than sulfuric acid or sulfamic acid. It is easy to handle and much safer to handle than either sulfuric or sulfamic acid solutions.

Any amount of urea sulfate can be used, with any molar ratio of urea and sulfuric acid, that performs the desired function. Given the disclosure herein, one of ordinary skill in the art can easily manipulate the ratio of urea and sulfuric acid, and the amount of salt used, to obtain a desired pH. Methods to determine pH are well known to those of skill in the art.

EXAMPLE 1 Preparation of Urea Sulfuric Acid 1:1

Salt.

Prilled urea (17.5 grams, 0.29 moles) was dissolved in 53.5 grams water. To this solution was slowly added sulfuric acid (29.0 grams, 0.26 moles, 89.3%) at 66°C. The temperature was maintained below 50°C in a cooling bath during the addition. The final solution on titration with 0.5 N NaOH (phenolphthalein indicator) was 5.3 N, which is equal to the theoretical value. EXAMPLE 2 Comparison of Efficiency of Product of Example 1 and Sulfamic Acid in Adjusting pH

The product of Example 1 (44.5% solids, 26% sulfuric acid solution) , as well as a 13% solids solution of 1:1 urea sulfate was compared to a 13% solids solution of sulfamic acid in tap water for ability to decrease pH. The results are provided in Table 1. As indicated, a 13% solids solution of sulfamic acid was approximately equal to a 13% solids solution of urea sulfate in ability to reduce pH. However, the 44.5% solids solution of urea sulfate was significantly more efficient at lowering pH than the 13% sulfamic acid solution. Since 15% is the practical concentration limit of sulfamic acid in water, its efficiency as a pH adjuster cannot be significantly increased by increasing its concentration.

Table 1

GRAMS 13% solids 13% solids 44.5% solids acid/liter Sulfamic Urea Sulfate Urea Sulfate

0 7.6 7.6 7.6 1 3.2 3.0 2.4

3 2.4 2.3 . 1.9

5 2.1 2.1 1.7

6 2.0 2.0 1.7

EXAMPLE 3 Comparison of Corrosivity of Product of Example l and Sulfamic Acid

The corrosivity on 316 stainless steel coupons of a 13% solids solution of sulfamic acid and a 13% solids solution of urea sulfate was compared by immersion of the coupon in the two solutions for 96 hours at 90-100°C. The results are provided in

Table 2. As indicated, a 13% urea sulfate solution is less corrosive to 316 stainless steel than a comparable solution by weight of 13% sulfamic acid.

Sulfate

Weight of coupon, init Weight of coupon, fina Weight loss % weight loss

Strong Acid Weak Base Salts As Equivalents to Urea Sulfate

Chemicals other than urea sulfate that can be used to adjust pH in textile processing include salts formed by the combination of a strong acid with a weak base. Strong acids are acids that are completely ionized in water. Ebbing, D.D., and Wrighton, M.S., "General Chemistry, Second Edition," Houghton Mifflin Company, Boston, pp. 327 (1987) . Examples of strong acids include mineral acids such as phosphoric, alkylphosphoric, arylphosphoric, sulfuric, alkylsulfuric, arylsulf ric, nitric, hydrochloric, hydrobromic, and others. Some acids commonly considered "weak" acids are also suitable. These include acids such as sulfamic, ethylsulfamic, carboxylic acids such as formic, acetic, propionic, acrylic, methacrylic, benzoic, and citric; dicarboxylic acids such as oxalic, aleic, glutaric, and malonic; styrene sulfonic acid, phosphonoformic, phosphonoacetic, carbamic, carbonic, sulfonic, alkyl sulfonic acid, aryl sulfonic acid (specifically including xylene sulfonic acid, toluene sulfonic acid, benzene sulfonic acid, cumene sulfonic acid, dodecylbenzene sulfonic acid, dodecyl diphenyloxide disulfonic acid, naphthalene sulfonic acid, benzaldehyde sulfonic acid, ethylnaphthalene sulfonic acid, trimethylbenzenesulfonic acid, aminobenzene sulfonic acid, halobenzeneεulfonic acid, alkoxybenzenesulfonic acid, benzophenone sulfonic acid, benzophenone disulfonic acid, halonaphthalene sulfonic acid, alkylnaphthalene sulfonic acid, alkoxynaphthalene sulfonic acid, carboxybenzene sulfonic acid (3-sulfobenzoic acid) , hydroxybenzenesulfonic acid, hydroxynapthalenesulfonic acid, carboxymethylbenzene sulfonic acid, alkylbenzene disulfonic acid, dicarboxybenzene sulfonic acid, acetamidobenzene sulfonic acid, acetaminonaphthalene sulfonic acid, naphthalene disulfonic acid, alkyl naphthalene disulfonic acid, dialkylbenzene disulfonic acid, biphenyl-4,4'- disulfonic acid, benzene and naphthalene sulfonic acids that contain combinations of halo, alkyl, hydroxy, carboxy, alkoxy, and acetamino groups, and sulfonated dihydroxydiphenylsulfone) , methanesulfonic, methylenediphosphonic acid, boric, thiocyanic, and others.

Weak bases are bases that are only partly ionized in water. Ebbing, D.D., and Wrighton,

M.S., "General Chemistry, Second Edition," Houghton Mifflin Company, Boston, pp. 327 (1987) . Nonlimiting examples of organic and inorganic bases are found on pages 8-37 through 8-39 in the "CRC Handbook of Chemistry and Physics," 72d Edition, CRC Press, (1992) , hereby incorporated by reference. Examples of weak bases include ammonia, urea, acetylurea, guanidine, hydroxyurea, semicarbazide; mono-, di-, or tri(alkyl or aryl)urea, and wherein in the case of di(alkyl or aryl)urea the alkyl or aryl groups can be on the same or different nitrogen atoms; mono-, di- or trialkyl or hydroxyalkyl a ine, specifically including mono-, di- and triethanolamine, O-methyl hydroxyl amine (methoxylamine) , aniline, ammonia, butylamine, ethylamine, ethylenediamine, hydrazine, and polyamines, including (mono or di)- alkylaminoalkylacrylate, and (mono or di)- alkylaminoalkylmethacrylate. Preferred bases are nitrogenous bases. Certain metal hydroxides, such as calcium and barium hydroxide, are weak bases and have low solubility in neutral media. However, they react with strong acids to form water and metal salts. These bases are not preferred because the resulting metal salts are relatively insoluble, compared to the acid salts of nitrogenous bases, and have a limited ability to alter the pH of textile processing solutions.

In another embodiment, a pH adjusting agent for textile processes is provided that is the salt of a strong acid and a strong base. Strong bases are bases that are completely ionized in water. Any strong base that forms a salt that exhibits the desired performance in a textile processing bath is suitable. Nonlimiting examples of strong bases include lithium, sodium, and potassium hydroxide. It should be understood that the strong acid/strong base salt should have at least one acidic proton to facilitate the lowering of the pH of the textile solution. Non-limiting examples of suitable salts include sodium bisulfate and potassium dihydrogen phosphate.

Examples of suitable salts include any salt that is formed by the combination of one or more of the acids listed above with one or more of the bases listed above, in any desired molar ratio. Examples specifically include the monobasic lithium, sodium, potassium and ammonium salts of polyacidic compounds, mono-, di-, or triethanolamine salts of sulfuric acid, the mono-, di-, or triethanolamine salts of phosphoric acid, urea phosphate, salts of aryl sulfonic acids and urea with mono-, di-, or triethanolamine, guanidine carbonate, guanidine hydrochloride, guanidine nitrate, the salt of urea with sulfamic acid, guanidine sulfate, and ammonium hydrogen sulfate. Any molar ratio of strong acid to weak base that serves the desired pH adjusting or other purpose can be used within the scope of this invention. Typical ratios, in terms of acid or base equivalents, are typically between approximately 4 to 1 and 1 to 4 acid:base equivalent units or a slight excess of base, in equivalence units. As with the urea sulfate, a 1:1 ratio by equivalent units is preferred, or slight excess of base.

EXAMPLE 4 Preparation of Sulfuric Acid (Tri and Di)-ethanolamine Salt

A sulfuric acid (tri and di)-ethanolamine salt useful for pH adjustment in textile processing was prepared by dissolving 41.8 g of an 85/15 mixture by weight of triethanolamine and diethanolamine in 28 grams of water, and then adding 30.2 grams of 89.3% sulfuric acid. The final solids content of the product was 48.9% by weight (28% sulfuric acid) .

Use of Urea Sulfate or its Equivalent in Textile Processing

The following examples are nonlimiting examples of procedures for adjusting pH in nylon dying and finishing activities. Given these examples, anyone of skill in the appropriate art can use the method disclosed herein to adjust the pH in processing solutions that include fibers or yarn other than nylon, for example silk, wool, rayon, other cellulosics, polyester, cotton, acrylics, and modacrylics, and at a variety of pHs. It is recommended that the desired salt, as opposed to the individual components, be added to the textile processing solution, to avoid a dilution effect, as well as corrosivity and safety problems associated with addition of the strong acid in the uncomplexed form.

Urea sulfate or its above-described equivalents, can be easily used as the pH adjusting agent for textile processing applied with any equipment, including but not limited to a Kuster's Flui-con foam applicator, pad applicator, exhaust dye beck, Kuster's flood applicator, continuous roller screen, silk screen applicators, overflow pans, kiss rollers, Kusters flexnips, pressure dye baths, tanning wheels for leather, and Kuster's Fluidyer. Urea sulfate or its above-described equivalents, may be less corrosive to this equipment than the traditional chemicals used for pH adjustment.

EXAMPLE 5 Dyebath Formula for Continuously Dyed Nylon Carpet

Table 3 provides a formula for an acid dyebath solution for continuously dyed nylon yarn that has been incorporated into carpet. The pH of this dye solution is approximately 4.5. Table 3 as necessary Tectilon Dyes

(Ciba-Giegy Dyestuff Corp.)

0.25 grams/liter Chelating agent (tetrasodium ETDA)

0.50 grams/liter Dowfax 2A1

(anionic acid dye leveling agent)

0.50 grams/liter DOSS (Dioctyl sulfosuccinate wetting agent)

0.25 grams/liter Product. of Example 1

EXAMPLE 6 Stain Blocking Aftertreat Bath

Solution for Nylon Carpets Applied with a Kusters "Flui-con" Foam Applicator using BASF Stain Protector

Table 4 provides a formulation for a finishing solution for nylon carpet for the application of BASF Stain Protector using a Kusters "Flui-con" foam applicator.

Table 4

30.0 grams/liter BASF Stain Protector (Stain blocking agent)

2.5 grams/liter Product of Example 1

7.0 grams/liter Peach State Labs KAF 260 (foaming agent)

The pH of this finishing solution is approximately 2.5.

EXAMPLE 7 Stain Blocking Aftertreat Bath

Solution for Nylon Carpets Applied with a Kusters Flui-con Foam Applicator using DuPont StainMaster

Table 5 provides a formulation for a finishing solution for nylon fiber or yarn for the application of DuPont stain resist agent with a Kusters Flui-con foam applicator.

Table 5

30.0 grams/liter SR-200 (Dupont Stainmaster stain blocking agent for nylon fiber)

5.0 grams/liter Product of Example 1

7.0 grams/liter PS Labs KAF 260 (foaming agent)

The pH of this solution is approximately 2.5.

Modifications and variations of the present invention relating to methods to adjust the pH in textile processing solutions will be obvious to those skilled in the art from the foregoing detailed description of the invention. Such modifications and variations are intended to come within the scope of the appended claims.

Claims

We claim .

1. A method for adjusting pH in a textile processing solution comprising: a) providing a textile processing solution; b) lowering the pH of the processing solution using the salt of a strong acid in combination with a weak base other than urea sulfate as the pH adjusting agent; and c) contacting the textile with the pH lowered textile processing solution.

2. The method of claim 1, wherein the acid is selected from the group consisting of phosphoric, alkylphosphoric, arylphosphoric, sulfuric, alkylsulfuric, arylsulfuric, nitric, hydrochloric, hydrobromic, sulfamic, methylεulfamic, formic, acetic, propionic, acrylic, methacrylic, benzoic, citric, oxalic, arylsulfonic, alkylsulfonic, maleic, glutaric, malonic, styrene sulfonic acid, phosphonofor ic, phosphonoacetic, carbamic, carbonic, sulfonic, methanesulfonic, methylenediphosphonic acid, boric, and thiocyanic.

3. The method of claim 1, wherein the base is selected from the group consisting of urea, acetylurea, guanidine, hydroxyurea, semicarbazide, alkylurea, dialkylurea, mono-, di- and tri-alkyl or hydroxyalkyl amines, O-methyl hydroxy1 amine, ammonia, aniline, ethylenediamine, hydrazine, and polyamine.

4. The method of claim 1, wherein the base is selected from the group consisting of mono, di and triethanolamine.

5. The method of claim 1, wherein the ratio of acid to base is approximately 1:1.

6. The method of claim 1, wherein the textile processing solution is used to treat nylon.

7. The method of claim 1, wherein the textile processing solution is a dyebath.

8. The method of claim 1, wherein the textile processing solution is a finishing solution.

9. The method of claim 1, wherein the textile processing solution contains a stain blocking agent.

10. The method of claim 11, wherein the molar ratio of strong base to polyacidic compound is between 1:1 and 2:1.

11. A method for adjusting pH in a textile processing solution comprising: a) providing a textile processing solution; b) lowering the pH of the processing solution using a salt of a strong acid with a strong base, wherein the salt has at least one acidic proton, as the pH adjusting agent; and c) contacting the textile with the pH lowered textile processing solution.

12. The method of claim 11, wherein the acid is selected from the group consisting of phosphoric, alkylphosphoric, arylphosphoric, sulfuric, alkylsulfuric, arylsulfuric, nitric, hydrochloric, hydrobromic, sulfamic, methylsulfamic, formic, acetic, propionic, acrylic, methacrylic, benzoic, citric, oxalic, arylsulfonic, alkylsulfonic, maleic, glutaric, malonic, styrene sulfonic acid, phosphonoformic, phosphonoacetic, carbamic, carbonic, sulfonic, methanesulfonic, methylenediphosphonic acid, boric, and thiocyanic.

13. The method of claim 11, wherein the base is selected from the group consisting of sodium, lithium and potassium.

14. The method of claim 11, wherein the textile processing solution is used to treat nylon.

15. The method of claim 11, wherein the textile processing solution is a dyebath.

16. The method of claim 11, wherein the textile processing solution is a finishing solution.

17. The method of claim 11, wherein the textile processing solution contains a stain blocking agent.

18. The method of claim 11, wherein the molar ratio of strong base to strong acid is between 1:1 and 2:1.

19. A method for treating textiles comprising the steps of: a) providing a textile processing solution; b) lowering the pH of the processing solution using urea sulfate as a pH lowering agent; and c) contacting the textile with the pH lowered textile processing solution.

20. The method of claim 19, wherein the urea sulfate is formed from a ratio of between approximately 1:4 and 4:1 moles of urea to sulfuric acid.

21. The method of claim 19, wherein the urea sulfate is formed from a molar ratio of urea to sulfuric acid of between 2.5 and 0.25 moles of urea to 1 mole of sulfuric acid.

22. The method of claim 19, wherein the urea sulfate is formed from an approximate 1:1 molar ratio of urea to sulfuric acid.

23. The method of claim 19, wherein the textile processing solution is used to treat nylon.

24. The method of claim 19, wherein the textile processing solution is a dyebath.

25. The method of claim 19, wherein the textile processing solution is a finishing solution.

26. The method of claim 19, wherein the textile processing solution contains a stain blocking agent.