Process for improving the dyeability of fabrics and fibers

Abstract: The printability and/or dyeability of fabrics or fibers comprising polyhydroxylized polymers is improved by treating a dry causticized fabric or fiber with a dilute solution of an ammonium salt of Formula I or II: and mixtures thereof, wherein R, R', R'' and R''' are C₁-C₂₀; X is sulfate, sulfonate or halide; and Z is selected from sulfate, sulfonate and halide . After wetting to a water content of less than 50 percent by weight, the wetted fabric or fiber is heated to fix the ammonium salt.

Description: The present invention relates to a process for improving the printability or dyeability of textile fibers and fabrics. More particularly, the invention relates to an improvement over the process disclosed in US-A-3,685,953 for printing or dyeing of polyhydroxylized polymers, such as cellulosic fibers and/or fabrics, by the pretreatment with an epoxy alkyl ammonium salt prior to printing or dyeing. In the dyeing of cellulosic textile materials and/or the printing thereof, it has been recognized that it is necessary to utilize various reactive compounds of an electropositive character to improve the fixing of the dyestuff on the fabric. Dyestuffs are employed of different characteristics for different textile material and, in general, some fabrics are less susceptible to dyeing with certain dyestuffs. Consequently, it has been recognized that there are certain additives which can be used to treat the fabric beforehand and/or simultaneously with the dyestuff to improve dye takeup and the fixing of the dyestuff to the fabric. It was known to use an epoxy ammonium compound having the following formula: wherein R, R' and R" are alkyl radicals and R"' is an alkylene radical, each independently having from 1 to 20 carbon atoms and X is an anionic group selected from sulfate, sulfonate and halide. The halides which may be used are fluoride, chloride, bromide or iodide. The additive may be utilized in two distinct processes. The epoxy compound may be applied to the textile material within the dyeing bath or the printing pastes, that is in the presence of the dyestuff which is to be taken up by the textile material. Also, the fabric prior to carrying out the dyeing process can be treated with the epoxy compound. It is known to fix the additive to cellulosic materials in the presence of an alkaline substance whose concentration increases inversely with the treatment temperature. In other words, higher concentrations of the alkaline substance are necessary with lower temperatures, and higher temperatures are required when lower concentrations of the alkaline substance are used. Generally, the alkaline substance is a strong base, preferably caustic soda, and extremely high concentrations are applied by the prior art to ensure fixation at low temperatures. However, treatments at elevated temperatures have become preferable to lower-temperature treatments utilized in the prior art because of faster processing and higher yields obtainable with the use of industrial equipment. It is known that treatment of the textile at high temperature, after it has been impregnated with an epoxypropylammonium salt, gives rise invariably to a strong yellowing thereof. The yellowing may not be removed in the course of the usual subsequent treatments. Such yellowing constitutes a considerable handicap to the use of epoxypropylammonium salts at high temperatures. The yellowing modifies or dulls the desired color and makes it impossible to obtain a white background in the printing of fabrics. Cuvelier et al., US-A-3,685,953, discloses a process of treating a hydrolyzed polymer such as cellulose with a solution of an epoxypropylammonium salt or the corresponding chlorohydrin, the solution also containing a strong mineral base as a fixation catalyst at a concentration of 0.5 to 10 % by weight, removing excess water and then drying at 80 to 140°C. However, the process results in low yields. Balland, US-A-3,853,460, relates to the use of alkylsulfosuccinates and alkylsulfosuccinamates with epoxypropylammonium salts to prevent hydrolysis of the salt to the dihydroxy compounds. Balland, US-A-4,072,464, relates to the use of boric acid with epoxypropylammonium salts to improve dye penetration of a cellulosic fabric and to decrease yellowing. The fabric is then heat treated at an elevated temperature. Gipp et al., US-A-4,035,145, relates to the use of N-(2,3-epoxyalkyl) ammonium salts such as N-methyl-N-(2,3-epoxypropyl)-morpholinium chloride in the presence of alkaline compounds to improve the dyeability of cellulosic textiles. Patton et al., US-A-5,006,125 discloses the use of epoxyalkyl ammonium salts or the corresponding chlorohydrin salts to improve the whiteness and/or dyeing characteristics of cellulosic fabrics (or fibers). When using an epoxyalkyl ammonium salt, the fabric is scoured with aqueous alkali; the scoured fabric treated with steam; excess alkali removed; and the fabric then treated with a solution of the epoxypropyl ammonium salt. Optionally, epoxyalkyl ammonium salt also is present in the scouring solution or applied to the scoured fabric prior to steaming. Specified methods of excess alkali removal are use of vacuum or aspirator means or washing with brine or water. Preferably, the fabric is steam treated after bleaching. When using a chlorohydrin salt, the scouring step is replaced by a bleaching step. Some Examples in US-A-5,006,125 reflux the scoured fabric in the scouring bath instead of treating with steam and in one of these Examples (Example 3) the fabric is then drained in a paper towel and passed through a laboratory padder to remove moisture. DE-A-3,129,990 discloses the pretreatment of cellulosic fibres, prior to dyeing with anionic dyestuffs, by treatment with aqueous alkali and then impregnation with aqueous solution of a quaternary ammonium salt of an epoxyalkyl or chlorohydrin. After the alkali treatment the fabric can be passed through a Foulard (padder) to reduce the wet pick-up. The impregnated fabric thereafter can be neutralised and/or washed with water. In a preferred embodiment the impregnated fabric is kept for 2 to 24 h at 15 to 30 °C or steamed for 20 to 60 sec at 100 to 110°C. It is understood that the term "polyhydroxylized polymer" as used herein relates to natural and synthetic polymers containing free hydroxyl groups which include cotton, flax, linen, rayon, and polyvinyl alcohol. The term "fabric" as used herein refers to fibers, yarns, tows, mats, battings, and cloth which comprise the polyhydroxylized polymer alone or in blends with other natural or synthetic fibers such as wool, polyester, and nylon. It is an object of the present invention to provide an improvement in printability and/or dyeability of fabrics comprising polyhydroxylized polymers by preconditioning the fabrics prior to dyeing or printing. It is a further object of the invention to improve the fixation yield of the epoxy ammonium salt of Formula I on cellulosic fabrics over that disclosed in US-A-3,685,953. It is yet another object of the invention to improve printability and/or dyeability of cellulosic fabrics without yellowing. The present invention provides in a first aspect an improved process for increasing the printability and/or dyeability of fabrics containing polyhydroxylized polymers. According to the process the fabric is first treated with a dilute alkaline solution and then the fabric is dried to an absorbent state so that the percentage of on weight fabric water is less than 8 percent. The dried fabric is then treated with a dilute solution of at least one ammonium salt selected from: and a mixture thereof, wherein R, R' and R'' are alkyl radicals and R"' is an alkylene radical, each independently having from 1 to 20 carbon atoms; X is selected from sulfate, sulfonate and halide; and Z is selected from sulfate, sulfonate and halide. R''' is preferably a lower alkylene group, that is, less than eight carbon atoms, and most preferably R"' is methylene. Advantageously, an aqueous solution containing from 0.1 to 10 percent by weight, preferably from 0.1 to 4 percent by weight, of the ammonium salt is utilized. Immediately after application of the ammonium salt solution, the fabric is dried and heated at an elevated temperature to fix the salt. Advantageously, the treating solution containing the ammonium salt is substantially free of any dihydroxyalkyltrialkylammonium salts which result from the hydrolysis of the epoxy compound in the presence of water at an alkaline pH especially of 11 to 13. The formation of the dihydroxyalkyltrialkyammonium salts has been found to constitute the primary yield loss in the reaction of the epoxy compound with cellulose. Cooling the treating solution temperatures below ambient conditions, preferably to 0°C, retards the hydrolysis reaction. Representative of the preferred compounds of Formula I include epoxypropyldiethylmethylammonium iodide, epoxypropyldiethylmethylammonium sulfate, epoxypropyltrimethylammonium chloride, and epoxypropyldimethyloctylammonium chloride. In order to increase the yield of fixation of the ammonium salt of Formula I or Formula II, it is essential that the fabric is first treated with an effective amount of an alkaline substance selected from alkali metal hydroxide, alkaline earth metal hydroxide, or a mixture thereof, preferably in the form of a dilute solution. The alkaline solution should have a concentration of less than 10 percent by weight, preferably from 2 to 4 percent and should be applied at a rate of less than 4 percent NaOH (dry basis) OWF to minimize irreversible yellowing of the fabric during the drying or curing steps. Optionally, a small but effective amount of sodium sulfite or other compatible reducing agent, for example, preferably from 0.1 to 10 percent by weight of the solution, more preferably from 1 to 4 weight percent, can be added to the alkaline solution to inhibit the formation of oxycellulose and thereby aid in minimizing yellowing. Use of sodium sulfite or other reducing agent is generally known in the art to be useful in minimizing yellowing of cellulosic fabric during processing steps carried out at elevated temperature. The molar ratio of base on the fabric to ammonium salt being applied to the fabric is optimally from 5:1 to 6:1, but this ratio may vary depending on the particular fabric and the amount of ammonium salt being applied. Any one or more of the alkali metal hydroxides, alkaline earth metal hydroxides or mixtures thereof may be utilized. The alkali metal hydroxides are preferred and sodium hydroxide is most preferred. It is known that the etherate group which is formed when the fabric is treated with a dilute alkali metal hydroxide solution is more reactive with an epoxy group than it is with a hydroxyl. It is further known that the alkali metal etherate form of the hydroxyls do not exist to any useful degree in the presence of water. It is also critical to achieving fixation of a higher amount of the epoxy form of the compound that the fabric is dry. That is, the amount of water present in the fabric prior to treatment with the ammonium salt should be less than 8 percent on weight fabric, preferably less than 0.5 percent on weight fabric in order to achieve uniform reagent application rapidly utilizing minimum water. The drying step conditions are not critical, but in combination are selected so as to accomplish drying to an absorbent state as promptly as is practical without causing irreversible yellowing. For example, drying of the fabric can be achieved at ambient pressure by drying at a temperature between 70 and 150°C and preferably in a low humidity atmosphere to minimize take up of any water from the atmosphere prior to treatment with the ammonium salt. As used herein, "low humidity" means an environment in which dry heat, rather than directly applied steam, is utilized as a source of thermal energy. With some drying equipment which can be used in practicing this invention, particularly heated rolls known as drying cans such as those available from Greenville Machinery Corp., Greenville, South Carolina U.S.A, or Morrison Textile Machinery Co., Ft. Lawn, South Carolina U.S.A., commonly used in the textile industry to dry broad woven textiles, the atmosphere in the vicinity of the equipment is humid because of water being driven off, but sufficiently rapid drying nevertheless results because the water of evaporation is allowed to dissipate rather than being deliberately confined or maintained by the addition of steam or water to the fabric. The fabric, having been treated with alkali metal hydroxide or other alkaline substance and dried, is left in a somewhat swollen state with sodium or other alkali ions remaining inside of the fiber. In this state, the fiber is capable of very rapidly imbibing an aqueous solution such as the aqueous solution of the ammonium salt. This rapid imbibition, along with the fact that the sodium or other alkali ions are already located within the fiber close to the desired reaction sites, allows a reduction in the time that the ammonium salt is in the presence of both alkali pH and water before the fabric can be dried to restore the reactive alkali metal etherate ligands. The epoxy compound is prone to hydrolyze in the presence of water, high pH, and high temperature. A reduction in the time during which the ammonium salt is exposed to these conditions is reflected in higher yield of the reagent ultimately reacted with the polyhydrolized medium. Hence the most desirable application of epoxy reagents is done from a solution which itself is at neutral pH but to a fabric which has been treated with an alkali hydroxide, and this application is followed as quickly as possible with flash drying. When the dry fabric with the etherate groups is wetted with the dilute aqueous solution of the reagent of Formula I or II respectively, a concentration of from 0.1 percent to 10 percent by weight reagent usually is used, and preferably, from 0.1 percent to 4 percent by weight. The dilute solution permits rapid penetration into the fibers and ultimately shortens the time required to take the epoxy/cellulose system to reaction conditions. The reagent solution containing at least one compound of Formula I or II is applied so that the fabric is wetted to achieve substantially uniform distribution of the reagent throughout the fabric, which may require a wet pickup of as little as 10 weight percent solution by weight of dry fabric. Using conventional dip and pad equipment, the wet pickup at the conclusion of this step of the process is usually at least 50 weight percent solution by weight dry fabric but not more than 100% (which is equivalent to the wetted fabric containing less than 50 weight percent water, respectively, by weight of the wet article). If a different application technique is used, such as applying the reagent solution as a spray or foam, or if the fabric is passed across a vacuum slot to remove excess reagent solution, the wet pickup at the conclusion of this step can be less than 50% solution by weight dry fabric Excess water is to be avoided since it necessitates a longer drying time to get to practical reactive conditions. The fabric is then heated and rapidly dried so as to cure or fix the ammonium salt in the fibers. Preferably, the heating is carried out as a flash drying operation in a low humidity environment to minimize the time at elevated temperature with water and reactive epoxy compound present because such conditions also promote hydrolysis of the epoxide to a dihydroxide and thereby reduce the yield of epoxide on the fabric. The heating preferably is at a temperature of at least 70°C, more preferably at least 100°C. Upper temperatures of 180°C, preferably 120°C, are sufficient. The fabric is heated at the preselected temperature for a period of time sufficient to effect the fixation without causing irreversible yellowing. Typically heating for 2 to 5 minutes, preferably 3 minutes. When a reducing agent is optionally employed to aid in minimizing yellowing, a heat treatment at from 120°C to 140°C for 1 to 5 minutes has been found to be quite practical. Heating may be carried out using commercial textile processing equipment, for example by passing the fabric over heated rollers or through a turbulent air drying oven. After the heat treatment, the fabric can be washed to remove any excess materials and then further processed under conventional means prior to treatment with a dyestuff or printing. When using the epoxy compound of Formula I, it is preferably prepared just prior to use by admixing the corresponding chlorohydroxylalkyltrialkyl ammonium salt with a base to avoid or at least to minimize the formation of the dihydroxy form caused by degradation of the epoxy compound due to the presence of water, high temperature and high pH. Figures 1 and 2 show the magnitude of the loss of yield due to the thermal instability of epoxypropyltrimethylammonium chloride derived from a 65 percent solution of 3-chloro-2-hydroxy-propyltrimethylammonium chloride which has been epoxidized using a 10-50 percent by weight solution of NaOH and which was at a pH between 10.5 and 12.5 at a temperature between 20°C and 50°C. Specifically, Figure 1 shows the half life of epoxidized Quat 188, that is, 65 percent 3-chloro-2-hydroxy-propyltrimethyl-ammonium chloride which has been epoxidized, as a function of temperature at a respective pH of 10.5, 11.0 and 11.5, and Figure 2 shows the half life of epoxidized Quat 188 as a function of temperature at a respective pH of 11.5, 12.0 and 12.5. An improvement in dyeability, printability and ease of handling at the point of application has also been found with the starting material used to prepare the epoxy ammonium salt, namely a compound of the formula: wherein R, R', R'', R''', X and Z are as hereinbefore described, preferably chlorohydroxypropyltrimethylammonium chloride. By following the steps of this invention, one can apply a solution of the halohydrin of Formula II without the need to premix the halohydrin with a base at the textile mill, as was customary practice. Having to premix the halohydrin with a base to form the active epoxy compound adds to the loss of the active species due to hydrolysis. According to the invention, there is provided a process for treating a fabric or fiber containing a polyhydroxylized polymer with at least one ammonium salt of Formula I or Formula II: wherein R, R' and R'' are alkyl radicals and R"' is an alkylene radical, each independently having from 1 to 20 carbon atoms; X is selected from sulfate, sulfonate and halide; and Z is selected from sulfate, sulfonate and halide, characterized by, in sequence: A. treating said fabric or fiber with an aqueous solution of at least one alkali metal hydroxide or alkaline earth metal hydroxide or mixture thereof; B. thermally drying the fabric or fiber from Step A to an absorbent state containing less than 8 percent water on weight fabric; C. contacting the dried fabric or fiber from Step B with a solution of the ammonium salt to wet the fabric or fiber, and then D. immediately heating the treated fabric or fiber from Step C at an elevated temperature in a low humidity environment. When a solution of the compound (I) is used, the polymer is contacted in step (A) with an aqueous solution of at least one alkali metal hydroxide or alkaline earth metal hydroxide or mixture thereof in a concentration which is sufficient, when Steps B and C are carried out, to promote reaction of the epoxy ammonium salt with the polymer. According to a specific embodiment of the invention, wherein the ammonium salt is an epoxy salt of formula (I), the dried fabric or fiber from Step B of said embodiment can include unreacted residue of the base, in which case Step C includes (i) contacting the dried fabric or fiber from step B with a dilute solution of at least one compound of the formula: wherein R, R' and R" are alkyl radials and R"' is an alkylene radical, each independently having 1 to 20 carbon atoms; X is selected from sulfate, sulfonate and halide; and Z is selected from sulfate, sulfonate and halide, and (ii) reacting said compound with unreacted residue of the base to form the epoxy ammonium salt in situ. The present invention will now be explained in detail by reference to the following non-limiting examples. Unless otherwise indicated, all percentages were by weight. A Despatch textile oven was used for all textile drying and curing steps. An Antek Total Nitrogen Analyzer was used for all nitrogen analyses of the fabric samples. Example 1 (INVENTION) The following experiment was performed to determine the washfast yield of epoxypropyltrimethylammonium chloride applied at a rate of 2 percent dry basis of epoxypropyltrimethylammonium chloride by weight of fabric to cotton fabric precausticized with 3 percent caustic by weight of fabric. To 15.38 grams of 65 percent 3-chloro-2-hydroxypropyltrimethylammonium chloride (Quat 188-The Dow Chemical Company) was added deionized water to make up a 400 gram solution. A 10 percent NaOH solution was added drop-wise to the Quat 188 solution until a pH of 11 was reached. 21.4 grams of the 10 percent NaOH solution was required. Two weighed cotton Testfabrics Style 400 printcloth samples were single dipped and padded with a 3 percent NaOH solution so as to achieve 100 percent wet pickup, and were dried on pin frames at 80°C for 3 minutes so as to have less than 8 percent water OWF. The fabric samples were mounted on pin frames and then sprayed with a 2 percent epoxidized Quat 188 solution from a range of 12" (30 cm) to be wetted and have a water pickup of less than 50 percent. The samples were weighed to determine the amount of solution uptake, mounted on a pin frames and then cured without delay for 2 minutes at 120°C. The samples were then washed by rinsing for 30 minutes in tap water followed by three rinses with deionized water. Several small pieces of fabric were cut from each cured sample, were weighed, and were visually checked for yellowing and then analyzed for nitrogen content. The nitrogen analyses showed the yields of reacted, washfast epoxidized Quat 188 to be 79.49 percent and 77.02 percent on the two samples. These yields were considerably higher than that found in US-A-3,685,953 in spite of the fact that the curing was done for a much shorter time in order to reduce yellowing of the fabric. The increase in yield shows the importance of pretreating the fabric with caustic and then bringing the pretreated fabric to a dry state. Comparative Run 1 The experiment was performed in order to determine the washfast yield of epoxypropyltrimethylammonium chloride. The procedure of Example 1 was repeated except that two weighed cotton Testfabrics Style 400 printcloth samples were pre-dried at 80°C for 3 minutes without dipping in the NaOH solution. The nitrogen analyses showed the yield of reacted, washfast epoxidized Quat 188 to be 9.77 percent and 12.38 percent on the two samples. This comparison shows the reduced yields which result from not including caustic in the reacting media. Example 2 (INVENTION) This experiment was performed to determine the washfast yield of epoxypropyltrimethylammonium chloride to cotton fabric precausticized with a 1 percent caustic solution. The procedure of Example 1 was repeated except that the two weighed cotton Testfabrics Style 400 printcloth samples were single dipped and padded with a 1 percent NaOH solution so as to achieve 100 percent wet pickup. The nitrogen analyses showed the yields of reacted, washfast epoxidized Quat 188 to be 31.82 percent and 21.72 percent on the two samples. This example shows the importance of the amount of caustic with which the cotton sample was pretreated relative to the amount of epoxy Quat with which the sample was treated. Comparative Run 2 This experiment was performed to determine the washfast yield of epoxypropyltrimethylammonium chloride first mixed with NaOH to a pH of approximately 13 and then applied at a rate of 1.65 percent epoxy compound dry basis of epoxypropyltrimethylammmonium chloride by weight of fabric to dry untreated cotton fabric. To 15.38 grams of 65 percent Quat 188 was added deionized water to make up 400 grams of solution. A 10 percent NaOH solution was added drop-wise to the Quat 188 solution until a pH of 11 was reached. 21.4 grams of 10 percent NaOH solution was required. A sample of Testfabrics Style 400 printcloth was cut, pre-dried at 80°C for 3 minutes and weighed. A 2 percent epoxidized Quat 188 solution was placed in a beaker with a magnetic stirrer together with a precalibrated Corning combination pH electrode. 10 percent NaOH was added to the 2 percent solution to obtain a pH of 13. The caustic treated solution was poured, without delay into a 8" (20 cm) x 10" (25 cm) Pyrex® baking dish immersed in an ice bath to maintain the treating solution near 0°C to minimize hydrolysis of the epoxide to the inactive dihydroxy alkyl compound. The sample was then dipped until visibly wetted throughout and padded without delay and weighed. The calculated amount of dry add-on Quat organic was found to be 1.65 percent. The fabric sample was placed on a pin frame and after exactly 5 minutes from treatment, it was placed in a Despatch oven to cure for 2 minutes at 120°C. The cotton fabric was then rinsed for 30 minutes in tap water followed by three rinses with deionized water. Several small pieces of fabric were cut from each cured sample, were weighed, and were then analyzed for nitrogen content. The nitrogen analyses showed the yields of reacted, washfast Quat 188 to be 64.67 percent, a greater yield than that found in US-A-3,685,953. This experiment shows the importance of minimizing the time duration during which the epoxy reagent is in the presence of water at an elevated pH. By lowering the temperature of the reagent bath, the reaction rate was reduced to the point that yield loss due to hydrolysis was less than usually encountered during the padding operation and before the water was removed by drying. Comparative Run 3 This experiment was performed to determine the washfast yield of 3-chloro-2-hydroxypropyltrimethylammonium chloride first mixed with NaOH at a concentration of approximately 2 percent and then applied at a rate of 6.0 percent organic compound dry add-on to dry untreated cotton fabric and was cured for 3 minutes at 120°C on a pin frame. This was performed to verify data from Example 13 of US-A-3,685,953. The prior art example used the same caustic and organic concentrations but used a cure time of 10 minutes at 120°C. The prior art example did not call for low temperature handling of the solution nor did it give any indication of the age of the solutions used. Since these factors were undefined, this sample was mixed and used at or near 0°C. The sample was cured with absolutely no delay after the padding operation. The one deviation from the prior art example was that a shorter cure time of 180 seconds at 120°C was used instead of the 10 minutes of the example, since it was known that the cited cure conditions would give severe yellowing of the sample. 18.5 grams of 65 percent Quat 188 chilled to approximately 0°C was weighed into a tared beaker. A solution of 40 grams of 10 percent NaOH diluted to 181.5 grams and chilled to 0°C, was added to the chilled Quat 188. A sample of Testfabrics Style 400 printcloth was cut, pre-dried at 80°C for 3 minutes and weighed. The chilled solution was poured into a 8" (20 cm) x 10" (25 cm) Pyrex® baking dish immersed in an ice bath, the fabric sample was then dipped until visibly wetted throughout, and padded without delay to have a water pickup of less than 50 percent. The fabric sample was then quickly put on a pin frame and placed in a Despatch oven to cure for 180 seconds at 120°C. The cotton fabric was then rinsed for 30 minutes in tap water followed by three rinses with deionized water. Several small pieces of fabric were cut from each cured sample, were weighed, and were then analyzed for nitrogen content. The nitrogen analyses showed the yields of reacted, washfast epoxidized Quat 188 to be 48.81 percent. The results thus obtained were only slightly lower than the 55 percent yield cited in Example 13 of US-A-3,685,953 and this difference was probably due to the reduced curing time required to reduce fabric yellowing. Comparative Run 4 This experiment was performed to verify data from US-A-3,685,953. It differs from Comparative Run 3 only in curing conditions. This experiment duplicates the curing time, (10 minutes) of the cited patent as well as all of the other conditions. The yield of washfast 3-chloro-2-hydroxy propyltrimethylammonium chloride was found to be 55 percent. The sample showed severe yellowing which was not removed with washing. This was in agreement with the cited 55 percent yield in US-A-3,685,953. Example 3 (INVENTION) This experiment was performed to determine the yield possible from the application of 3-chloro-2-hydroxypropyltrimethylammonium chloride to precausticized very dry cotton fabric. The experiment was performed using 3-chloro-2-hydroxypropyl-trimethylammonium chloride (Quat 188) applied at a rate of 2 percent dry add-on to cotton fabric precausticized with 3 percent caustic add-on and then dried. 65 percent Quat 188 was diluted with deionized water to make up 200 gram of 2 percent active ingredient solution. A cotton sample was single dipped and padded with a 3 percent NaOH solution so as to achieve 100 percent wet pickup. The sample was pre-dried at 80°C for 3 minutes followed by drying with bone dry nitrogen at room temperature for 16 hours. The causticized and dried sample was mounted on a pin frame and sprayed from a range of 12" (30 cm) with a 2 percent epoxidized Quat 188 solution. The sample was weighed to determine the amount of solution uptake. The sample was then mounted on a pin frame and cured without delay for 2 minutes at 120°C. The sample was then rinsed for 30 minutes in tap water followed by three rinses with deionized water. Several small pieces of fabric were cut from each cured sample, were weighed, and were then analyzed for nitrogen content. The nitrogen analysis showed the yield of reacted, washfast Quat 188 to be 61.6 percent. This yield was appreciably higher than the yield of 55 percent cited in US-A-3,685,953 and utilized curing conditions which were less severe, resulting in much less irreversible yellowing of the fabric. Based on the yield achieved in Example 1 using the epoxy compound, it is expected that a further improved yield above the 61.6 percent obtained in this experiment could be achieved by increasing the caustic to 3-chloro-2-hydroxytrimethylammonium chloride ratio, preferably by reducing the concentration of the chlorohydrin rather than increasing the caustic to minimize risk of yellowing.

Claims: A process for treating a fabric or fiber containing a polyhydroxylized polymer with at least one ammonium salt of Formula I or Formula II: wherein R, R'and R'' are alkyl radicals and R''' is an alkylene radical, each independently having from 1 to 20 carbon atoms; X is selected from sulfate, sulfonate and halide; and Z is selected from sulfate, sulfonate and halide, characterized by, in sequence: A. treating said fabric or fiber with an aqueous solution of at least one alkali metal hydroxide or alkaline earth metal hydroxide or mixture thereof; B. thermally drying the fabric or fiber from Step A to an absorbent state containing less than 8 percent water on weight fabric; C. contacting the dried fabric or fiber from Step B with a solution of the ammonium salt to wet the fabric or fiber, and then D. immediately heating the treated fabric or fiber from Step C at an elevated temperature in a low humidity environment. A process for printing or dyeing a fabric or fiber containing a polyhydroxylized polymer characterized in that the fabric or fiber is treated by a process of Claim 1 and the treated fabric or fiber is printed or dyed. A process as claimed in Claim 1 or Claim 2, wherein said ammonium salt is an epoxy ammonium salt of said Formula I. A process as claimed in Claim 3, wherein said epoxy ammonium salt is epoxypropyltrimethylammonium chloride. A process as claimed in Claim 1 or Claim 2, wherein said ammonium salt is an ammonium salt of said Formula II. A process as claimed in Claim 5, wherein said ammonium salt is a halohydrin. A process as claimed in Claim 6, wherein said ammonium salt is 3-chloro-2-hydroxypropyltrimethylammonium chloride. A process as claimed in any one of Claims 1, 2, 3 and 5, wherein R'' is C 1 -C 7 alkylene. A process as claimed in Claim 8, wherein R"' is methylene. A process as claimed in any one of the preceding claims, wherein said solution of Step A contains 2 to 4 weight percent alkali metal or alkaline earth metal hydroxide. A process as claimed in any one of the preceding claims, wherein the alkali of Step A is applied at a rate of less than 4 percent (calculated as NaOH) alkali on weight fabric. A process as claimed in any one of the preceding claims, wherein Step B is carried out until the fabric has less than 0.5 percent water on weight fabric. A process as claimed in any one of the preceding claims, wherein said solution of Step C contains 0.1 to 4 weight percent of said ammonium salt. A process as claimed in any one of the preceding claims, wherein the solution of Step C is substantially free of dihydroxyalkyltrialkylammonium salts. A process as claimed in any one of the preceding claims, wherein the solution of Step C is sprayed on said fabric. A process as claimed in any one of the preceding claims, wherein the solution of Step C has a pH of from 11 to 13 and until brought into contact with the fabric or fiber is maintained at a temperature of less than ambient in order to minimize the reaction of the ammonium salt with the water in the solution. A process as claimed in any one of the preceding claims, wherein the molar ratio of base on the fabric or fiber to ammonium salt is 5:1 to 6:1. A process as claimed in any one of the preceding claims, wherein Step B is carried out at a temperature of from 70 to 150°C and Step D is carried out at a temperature of from 70°C to 180°C for 2 to 5 minutes. A process as claimed in any one of the preceding claims, wherein said fabric or fiber comprises cotton. A process as claimed in any one of the preceding claims, wherein the ammonium salt is an epoxy ammonium salt of Formula I, the dried fabric or fiber from Step B includes unreacted residue of the base, and Step C includes (i) contacting the dried fabric or fiber from step B with a dilute solution of at least one compound of Formula II, and (ii) reacting said compound with unreacted residue of the base to form the epoxy ammonium salt in situ.

Inventors: HILL STEPHEN E, PATTON ROBERT THOMAS, ROERDEN DOROTHY L, HILL, STEPHEN E., PATTON, ROBERT THOMAS, ROERDEN, DOROTHY L.
Applicants: DOW CHEMICAL CO, THE DOW CHEMICAL COMPANY
Application year: 1993
Main classification: D06P5
IPC codes: D06P5, D06P1, D06M13