US3811210A - Mild cure finishing process incorporating improved catalyst systems to produce wrinkle resistant, durably pressed and creased cellulosic textile products - Google Patents

Abstract

Improved catalyst systems have been found that can be used in place of the strong mineral acid catalysts previously required in the mild cure finishing process for cellulosic textiles. These improved catalyst systems consist of mixtures of ammonium chloride and an acid selected from the group, phosphoric acid, citric acid, oxalic acid, tartaric acid, and trichloroacetic acid. Unlike cellulosic fabrics treated by the mild cure finishing process with strong mineral acid catalysis, fabrics similarly processed with the improved catalyst systems need not be neutralized and washed immediately after curing to prevent strength loss during subsequent storage. The wrinkle resistant fabric thus produced may be used as a precured product or may be additionally processed to impart shape and creases by a combination of steam pressing and dry pressing.

Description

United States Patent 191 Cashen et al. 9

[11] 3,811,210 May 21, 1974 [73] Assignee: The United States of America as represented by the Secretary of Agriculture, Washington, DC.

221 Filed: Jan. 26, 1972 211 'Appl.No.:221,079

[52] US. Cl 38/144, 2/243, 8/1 15.7,-

[51] Int. Cl. D06m 13/12 D06m 13/34 [58] Field of Search 8/183, 187, 185, 186; 38/144; 2/243 [56] References Cited UNITED STATES PATENTS 3/1968 Cotton 8/183 X 5/1972 Gordon 8/187 X 4/1969 Pierce et al 8/187 x 6/1969 Ross et al. 8/187 3,094,371 6/.1963 Van Loo et al....., ll7/l39.4 X

y OTHER PUBLICATIONS Pierce et al., American Dyestuff Reporter, Vol. 57, No. 22, Oct. 21', 1968, Pages 47-51. Reinhart et al., Textile Chemist and'Colorist, Vol. 1, Sept. 24, 1969, Pages 415-422.

Primary ExaminerHerbert B. Guynn Attorney, Agent, or Firm-M. Howard Silverstein; Max D. Hensley 57 ABSTRACT .Improved catalyst systems have been found that can be used in place of the strong mineral acid catalysts previously required in the mild cure finishing process for cellulosic textiles. These improved catalyst systems consist of mixtures of ammonium chloride and an acid selected from the group, phosphoric acid, citric acid, oxalic acid, tartaric acid, and trichloroacetic acid. Unlike cellulosic fabrics treated by the mild cure finishing process with strong mineral acid catalysis, fabrics similarly processed with the improved catalyst systems need not be neutralized and washed immediately after curing to prevent strength loss during subsequent storage. The wrinkle resistant fabric thus produced may be used as a precured product or may be additionally processed to impart shape and creases by a combination of steam pressing and dry pressing.

20 Claims, No Drawings MILD CURE FINISHING PROCESS INCORPORATING IMPROVED CATALYST SYSTEMS TO PRODUCE WRINKLE RESISTANT, DURABLY PRESSED AND CREASED CELLULOSIC TEXTILE PRODUCTS A non-exclusive, irrevocable,royalty-free license in the invention herein described throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

FIELD TO WHICH INVENTION RELATES This invention relates to the chemical finishing of cellulosic textiles. More particularly it relates to improved catalyst systems for use in the mild cure finishing process for producing wrinkle resistant, durably pressed and creased, cellulose-containing apparel and home furnishing textile items. Specifically, it relates to catalyst systems that can be used in combination with relatively mild heating for the curing step in the treatment of cellulosic textile materials with'crosslinking agents to produce a wrinkle resistant product that may be additionally processed to impart shape and creases.

THE PRIOR ART Recently, another type of finishing process to produce wrinkle resistance has been pioneered in Europe.

This new type of finishing has been called damp crosslinking or moist-cure finishing (feuchtvernetzung, in German). The process is taught in U.S. Pat. No. 3,409,462. In this process, cellulose fabric is impregnated with a solution containing a methylol-type crosslinking agent and strong acid catalyst, and the pickup adjusted in the usual manner. The fabric is then dried to a moisture content of between 4 percent and 30 percent, held in this damp state at about room temperature for from 4 to 30 hours, then neutralized, washed and dried. The products of damp crosslinking have certain properties that are desirable in finished cottons. Among these are high dry and high wet wrinkle resistance which give good smooth dry appearance when no tumble dryer is available and line drying is used.

A simpler process to produce treated fabrics with properties similar to those of the damp crosslinking method has been developed which is more suitable to American finishing practice. The new finishing method, called the mild-cure finishing process, has eliminated the need for the long treatment period during which the moisture content must be carefully controlled. The mild-cure finishing process is faster than the damp crosslinking method-it permits greater production rates, and requires less space in the plant as the fabric need not be held at an'intermediate stage during treatment.

The mild-cure finishing process was first described at the 8th Cotton Utilization Research Conference, May

1-3, 1968 (see Proceedings, pages 87-92, published by U.S. Department of Agriculture as ARS 72-70 in May 1969). Additional details of the process were published in Textile Chemist and Colorist, Vol. 1, pages 415-422, Sept. 24, l969and Textile Chemist and Colorist, Vol. 2, pages 337-340, Sept. 23, 1970. The mild-cure finishing process consists essentially of the following steps: (1) impregnating the fabric with an aqueous solution containing a cellulose crosslinking agent and a strong mineral acid catalyst; (2) heating the impregnated fabric under mild conditions for a relatively short time without prior drying; (3) neutralizing and washing the treated fabric; and (4) drying the washed fabric.

Wamock and Hubener in U.S. Pat. No. 2,974,432 disclosed a variation of the traditional pad-dry-cure process by which it was possible to produce durably pressed and creased garments. In their variation, which is now commonly called the post-cure process, Warnock and Hubener taught that after drying the finishing agent-catalyst impregnated fabric, garments could be cut,- sewn, trimmed, and pressed to shape, including creases, pleats, and the like, and then cured in an oven,

at temperatures ranging from 350 to 450 F, to' make the shape durable to laundering. This process is also referred to as deferred-cure finishing and delayed-cure finishing. The finishing agents used in post cure finishing and diand polyfunctional'N-methylolamides, such as dimethylol dihydroxyethylene-urea, dimethylol alkyl and modified alkyl carbamates, methylolated triazines, and the like Catalysts for post cure finishing are Lewis acid salts such as zinc nitrate, zinc chloride, magnesium chloride, and the like.

In U.S. Pat. No. 2,957,746 Buck and Getchell disclose another method for obtaining durable creases in garments made of wrinkle resistant cellulosic fabric. If fabric is wrinkle resistant, it is also resistant to receiving a durable crease. Buck and Getchell teach that creases can be introduced into wrinkle resistant fabric by wetting the area of the garment to be creased with a warm solution of an acidiccatalyst, folding the fabric along the wetted area, and applying heat and pressure until the wetted area is dry. Theacidic catalyst, under these conditions, breaks the chemical bonds between the fabric and the crosslinking agent, which bonds confer wrinkle resistance to the fabric, and then reforms the bonds so that the crease is durably set in the fabric. This method of creasing has a number of inherent difficulties. Among these are'water spotting from the acidic catalyst solution, shade change of dyes in the creased area, and additional tendering of the fabric in the creased area from the hot, acidic treatment.

THE PROBLEM The strong acid catalysts used in mild cure finishing, although they provide an excellent driving force for the cellulose crosslinking reaction under relatively mild heating, have a particularly bad disadvantage. After the curing step, acidity from the residual strong acid catalyst in the treated fabric must be neutralized and the fabric washed prior to prolonged storage to prevent degradation of fabric strength due to acid hydrolysis of the cellulosic substrate. This imposes a serious limitation on the attractiveness of the mild-cure finishing process as the general practice in textile finishing of fabrics for improved wrinkle resistance is to omit washing and drying operations after curing the treated fabrics.

wrinkle resistance are not universally applicable as catalysts in mild-cure finishing. a

Highly acitve catalyst systems for use in pad-dry-cure finishing have been disclosed by Pierceand Frick in US. Pat. No. 3,441,367 which are mixtures of magnesium chloride and an alkoxy or hydroxy substituted carboxylic acid. However, these catalysts must be used in finishing treatments in which the fabric is dried prior to the curing. Catalysts of this type have been tried in miId-cure finishing but have not produced sufficiently .high levels of wrinkle resistance in the finishing fabric.

Another catalyst system consisting of an acidic component and a salt component forwet fixation of aminoplasts in textiles is taught by Cotton in US. Pat. No. 3,374,l07. However, the wet fixation treatment process in which the catalysts are employed requires that the moisture content of the textile'must be maintained above the normal moisture regain of the fabric. In mildcure finishing, the process of the instant invention, the moisture content of the fabric during treatment goes down to a value considerably below that of the normal regain of the fabric. For example, the normal moisture regain of cotton is about 6-7 percent. In mild-cure finishing, the moisture content of the fabric after the heat treatment step is about 2-5 percent.

No satisfactory process has been developed to provide a fabric that is wrinkle resistant but is also amenable to creasing and shaping by a mere combination .of steam and heat atlow temperatures.

OBJECTS OF THE INVENTION HOW THE OBJECTIVES ARE ACHIEVED We have found that improved catalysis for mild-cure finishing of cotton and other cellulosic textiles is provided by catalyst systems consisting of mixtures of ammonium chloride and phosphoric acid or certain organic acids. These catalyst systems are effective as alternatives to strong mineral acids as catalysts in'mildcure finishing. They provide the added advantage of fabrics of the process of this invention in the home by ironing with a home-type hand iron.

The'process of the instant invention may thus be described asthat in which a cellulosic textile material is (a) impregnated with a solution containing (i.) a suitable N-methylol type finishing agent capable of crosslinking the cellulose and (ii.) a mixture of ammonium chloride and phosphoric, oxalic, tartaric, citric, or trichloroacetic acid which serves as catalyst for the cross linking reaction; and (b.) the impregnated fabric is then heated under mild conditions which dry the fabric down to about 25 percent moisture content and in so doing may promote the crosslinking reaction to impart wrinkle resistance properties in the fabric. After curing, the finishing fabric may be stored for prolonged periods without first neutralizing residual catalyst and washing out unboundresidues. No strength'loss occurs during storage by omission of these two steps.

If fabric is to be fabricated into garments in a post cure process, the impregnated fabric of step (b) need only be dried prior to storage. Subsequent steps then include after (b) above, the following: (0) cut and sew fabric into an apparel or home furnishing item, (d) shape and crease with steam pressing or steam ironing as is appropriate to the item; and (e) heat at a temperature of about lOO-l20 C. to set the finish or hand iron. The process durably sets the creases and smooth pressed appearance so that this appearance will persist through repeated laundering and drying without the need of further ironing or pressing. In addition to the finishing agent and catalyst, the treatment solution can contain softeners, hand-builders, or other textile finishing additives as desired by the operator and well-known to those skilled in the art. The process employs treatment temperatures for the curing operation that are markedly lower than those required in the widely used post-cure process, i.e., l00f-l20 C vs. about l80-230 C (about 350450 F). Such markedly lower operating temperatures afford great savings in plant power requirements to produce the heat needed in the present process. Much equipment that is incapable of operation at the temperatures required in the widely-used, high temperature post-cure durable-press process can readily operate at the relatively mild temperatures sufficient in the process of the present invention. Furthermore, the fabric is suitable for the home ironed and they dry ironed in the home to accomplish not requiring neutralization and washing of the treated fabric after drying or curing to prevent degradation of the fabric and consequentlosses of strengthduring prolonged storage. They further provide theme'ans to produce a fabric that can be shaped and creased by steam pressing and post curing at mild cure temperatures. Furthermore, creases can be cured into the finished the final setting operation. Heretofore, there has been no such product available to the home sewing market that could be simply processed to achieve durable creases and smooth drying appearance.

The textile materials processedmay be in the form of fibers, yarns, or fabric. The preferred form for treatment is fabric. The fabric may be composed of cellulosic fibers, either natural, such as cotton, linen, ramie, and the like, or regenerated fibers such as rayon, polynosic, and the like. Furthermore, the fabric may be I00 percent cellulosic fibers, or woven from a blend of cellulosic fibers and. synthetic fibers such as cotton/- polyester fabric, rayon/polyester fabric, cotton/nylon fabric and the like.

Carbamate finishing agents, that is, adducts of formaldehyde and various carbamic acid esters, such as methyl carbamate, ethyl carbamate, isopropyl carbamate, n-propyl carbamate, isobutyl carbamate, n-butyl carbamate, hydroxyethyl carbamate, hyd-roxypropyl carbamate, methoxyethyl carbamate, and the like, are the agents of choice for this process. These agents are generally termed dimethylol agents, that is, dimethylol methyl carbamate, dimethylol ethyl carbamate, etc. They may be represented by the formula ROCON(Cl-l Ol-l) in which R is an alkyl or modified alkyl group, that is, methyl, ethyl, isopropyl, n-propyl, isobutyl, n-butyl, hydroxyethyl, hydroxypropyl, or methoxyethyl. The concentration of carbamate finishing agent employed in the treatment may be varied in the range of from about 5 percent to about 35 percent by weight, based upon the total weight of the finishing solution. The preferred range of concentrations is from about percent to about percent. Other agents found suitable for the invention include dimethylol dihydroxyethyleneurea and bis-isopropoxymethyl dihydroxyethyleneurea.

Catalysis for the treatment is provided by mixtures of ammonium chloride and phosphoric, oxalic, tartaric, citric, or trichloroacetic acid. The catalyst mixtures may be varied in composition from that with aratio of about one mole of ammonium chloride to about two moles of the acid to that with a ratio of about two moles of ammonium chloride to about one mole of the acid. The concentration of the catalyst mixture used may be varied from about 0.5 percent to about 3.4 percent, by weight, based upon the total weight of the treatment solution.

Neither of the components of the mixed catalyst, if used alone, is suitable as catalyst in the process'of this invention. That is, the described mixtures of ammonium chloride and phosphoric, oxalic, tartaric, citric, or trichloroacetic acid provide effective catalysis to produce wrinkle resistance in the mild cure finishing process whereas ammonium chloride, phosphoric acid, oxalic acid, tartaric acid, citric acid, and trichloroacetic acid, singly as catalysts under mild cure conditions, give finishes with wrinkle resistances scarcely above that of the untreated fabric.

lmpregnation of the fabric with the solution containing the finishing agent and mixed catalyst may be accomplished by any convenient means. Conventionally, this is done by immersing the fabric in the treatment solution, and passing through pad rolls to adjust the pickup of solution and to give even penetration and distribution of the treatment solution throughout the fibers of the textile material. The pickup of treatment solution in the wet, impregnated fabric can be adjusted within the range'of from about 50 percent to about 120 percent based upon the dry weight of the untreated fabric. The preferred range of Wet pickup is from about 75 percent to about 100 percent based upon the dry weight of the untreated fabric.

To impart wrinkle resistance using only steps (a) and (b) of the process, curing conditions which may be employed in this invention include heating the fabric at a temperature of from about 80 C to about 100 C for period of time of from about 1 minute to about 6 minutes in an oven, chamber, tenter frame, or other equipment provided with means of circulating and exhausting the heated air. These mild-cure finishing conditions are adjusted so that in curing the moisture content of the treated fabric is reduced to about 2 to 5 percent. The exact conditions required vary with the equipment used and the material being treated. If the moisture content of the treated fabric is much higher than about 5 percent, the treatment fails to develop a suitable level of dry (conditioned) wrinkle resistance although a considerable degree of reaction may occur between the cellulose and the finishing agent. If the moisture content of the fabric is reduced to much below about 2 percent in the curing step, severe loss of strength is suffered by the treated material.

Although washing the treated fabric after the curing step is essential in mild-cure finishing with mineral acid catalysis, it is a special feature of this invention that omission of an afterwash does -not result in additional strength loss from degradation of the cellulosic substrate by residual catalyst and byproducts in the treated fabric. If an afterwash is included in the finishing treatment, any conventional washing procedure is suitable.

To impart durably pressed and creased fabric, following steps (a) through (e), the wet-impregnated fabric is preferably dried by heating at a temperature of about from C. to 100 C. for about from I to 12 minutes to reduce the moisture content to about 2 to 5 percent. After storageand apparel fabrication, creasing of the treated fabric is accomplished by use of steam and heat, preferably by employing a steam press or steam iron. This stepis necessary to redistribute crosslinks between the finishing agent and the cellulosic hydroxyl groups.

Post curing is accomplished by heating the creased and shaped material at 100l20 C in an oven, the time used will vary with the fabric construction and fiber constitution of the fabric, but generally 2 to 4 minutes is satisfactory. lf post curing is accomplished with a hand steam iron followed by dry ironing, the iron temperature should-not exceed 165 C.

SUMMARY OF THE INVENTION In summary, this invention may be described as a process for finishing cellulose-containing textile materials to produce wrinkle resistant and durably creased and pressed products. The utility of such fabrics is widely recognized. Once deemed only a convenience,

wrinkle resistance and durable press have gained in importance to the consumer as properties of clothing and household items until they are now considered by many to be a necessity. The process of the invention is carried out with mixed catalyst systems which are effective under mild-cure finishing conditions. The process may be summarized as:

1. To achieve wrinkle resistance only.

(a.) Impregnating a cellulosic fabric to about -100 percent wet pickup of a solution containing about 10-20 percent of a formaldehyde-carbamate adduct of the formula ROCON(CH OH) in which R is a methyl, ethyl, isopropyl, n-propyl, isobutyl, n-butyl, hydroxyethyl, hydroxypropyl or methoxyethyl group, and about 0.5-3.4 percent of -a mixture of ammonium chloride and phosphoric, oxalic, tartaric, citric, or trichloroacetic acid which may vary in content from a molar ratio of 1:2 to 2:1, said mixture serving as catalyst for the finishing reaction.

(b.) Heating the wet, impregnated fabric in a suitable apparatus at about 80-100 C for about l-6 minutes with circulation and exhaust so that the treated fabric contains about 2-5 percent moisture at the end of the treatment.

2. To achieve durably pressed and creased fabric:

(a.) lmpregnating a cellulosic fabric to about 80l00 percent wet pickup of a solution containing about -20 percent of an agent selected from the group consisting of a formaldehyde-carbamateadduct, a dimethylol dihydroxyethyleneurea and a bisisopropoxymethyl dihydroxyethylen'eurea, and about 0.3 to 3.4 percent of a mixture of ammonium chloride and phosphoric acid, citric acid, oxalic acid, tartaric acid, and trichloroacetic acid which may varyin content from a molar ratio of 1:2 to 2: 1, said mixture serving as catalyst for the finishing reaction;

(b.) Heating the wet, impregnated fabric in a suitable apparatus at a temperature of about from 60 C. to about 100 C. for about from 1 to 12 minutes to reduce moisture content of the fabric to 2-5 percent;

(c.) After storage, cut and sew into an apparel or home furnishing item;

(d.') Shape and crease with a steam press or steam iron as is appropriate to the item;

(c.) Heat at a temperature of about l00-l20 C to cure the finish, and alternatively iron with a home type hand iron at no greater than 165 C to cure the finish and durably set the creases and smooth, pressed appearance.

The following examples further describe many aspects of the invention in detail. All percentages cited are by weight. Recognized test procedures have been used for the determination of the properties of the fabl'lCS.

Example 1 Swatches of cotton printcloth were impregnated with a solution containing percent dimethylol methyl carbamate and 2 percent of an equimolar mixture of ammonium chloride and phosphoric acid. The wet, impregnated fabrics were pinned on frames and mild cured by heating in a forced air-circulation oven at 100 C for 4 minutes which reduced the moisture content of the treated fabrices to about 2-3 percent. One treated swatch (Sample 1A) was washed immediately and dried. The remaining treated swatches were stored, under ambient room conditions, approximately 22 C and 50-60 percent relative humidity, for various periods of time as follows:

Sample 18: Stored 2 weeks, then washed and dried.

Sample 1C: Stored 8 weeks, then washed and dried.

Sample 1D: Stored 12 weeks, then washed and dried.

Table I Sample Breaking Strength Wr. Rec. Angle (W+F), deg. (W), lb. 1 Cond. Wet

M 28.3 271 250 1H 30.7 262 258 IC 28.3 263 27) ID 29.) 262 280 8 From the results given in the table, it is obvious that there is no change in strength nor adverse effect on wrinkle resistance as a consequence of deferring the afterwash for periods as long as 12 weeks. That is, there is effectively no degradation of the finish nor of the fabric substrate from omission of the wash step in mild cure finishing when the mixed catalysts of the present invention are employed.

These results are in stark contrast with those obtained when a strong, mineral acid catalyst is employed in mild cure finishing and the treated fabric is not washed'immediately. The consequences of the latter have been shown in the technical literature (i.e., FIG. 4, on page 417 of the Textile Chemist and Colorist, Volume 1, No. 20, Sept. 24, 1969) in which a progressive strength loss resulted from storage of the mild cure finished fabric without neutralization and an afterwash.

V The loss of strength due to acidic degradation of the fabric substrate progressed to about 30 percent in 12 .weeks of storage without an afterwash to remove residual catalyst and byproducts after the mild cure treatment.

Examples 2-9 illustrate the efiectiveness of the new catalyst system in affecting reaction between the cellulosic substrate and carbamate-formaldehyde adducts to achieve high levels of fabric wrinkle resistance.

Example 2 A yardage of cotton printcloth was impregnated with a solution that contained:

15 parts of dimethylol methyl carbamate 0.67 parts of ammonium chloride 1.37 parts of phosphoric acid 82.96 parts of water by passing the fabric into the solution and then through pad rolls twice to adjust the wet pickup of solution to about 90 percent (i.e., 100 parts of dry fabric picked up 90 parts of solution). The wet, impregnated fabric was then given a mild-cure treatment by passing it through a tenter frame, equipped with heaters and blowers, at 100 C with a dwell time of 1 minute and 14 seconds. Moisture content of the treated fabric wasand phosphoric acid (H PO Concentration of the mixed catalyst was about 2 percent of the treatment solution.

Example 3 Samples of cotton printcloth were impregnated with solutions containing 15 percent dimethylol methyl carbamate and 2 percent of an equimolar mixture of ammonium chloride and tartaric, oxalic, citric, or trichloroacetic acid. The wet, impregnated fabrics were 9 duced the moisture content of the treated fabrics to about 3 percent. The treated fabrics were; analyzed for nitrogen content and wrinkle resistance after washing. Another set of samples were prepared as controls by similar treatment but with solutions containing. 15 percent dimethylol methyl carbamate and as catalyst one of the various components of the above treatments. All of the results are shown in Table 11. It is obvious from the data that the catalysis provided by the mixtures of ammonium chloride and the acids is much more effective than that of the mixed catalyst components used individually. I

Table II For Sample 5A: percent dimethylol methyl carbamate and 2.78 percent of a mixture of ammonium chloride and phosphoric acid in a 2:1 molar ratio of the former to the latter.

For Sample 58: 15 percent dimethylol methyl carbamate and 3.33 percent of a mixture of ammonium chloride and phosphoric acid in a 1:2 molar ratio of the former to the latter.

The wet, impregnated fabrics were mild cured as in Example 4. Results of analyses and tests after washing are given in Table W.

M Wr. Rec; Angle, Cond.

Catalyst %N (W+F), degrees 2% Equimolar mixturezNHfll/tartaric acid 1.03 257 2% Equimolar mix'turezNHfll/oxalic acid 1.15 259 2% Equimolar mixturezNH cllcitric acid 0.92 242 2% Equimolar mixture:NH Cl/trichloroacetic acid 1.17 245 1.3% phosphoric acid 0.39 191 1.5% tartaric acid 0.25 177 1.2% oxalic acid 0.79 223 1.9% citric acid 0.19 169 1.6% trichleroacetic acid 0.96 226 0.5% NH CI 0.20 199 Untreated 171 Example 4 Table IV Samples of cotton printcloth were impregnated with solutions containing 15 percent dimethylol methyl car- 53mph %N fzj fgi" Angle bamate and, as catalyst, various concentrations (0.5-3 Cond. Wet percent) of an equimolar mixture of ammonium chlor- 5A I 20 2'8 4 266 265 ide and phosphoric acid. The wet, impregnated fabrics 53 270 v 271 were pinned on frames and mild cured by heating in a forced air-circulation oven at 100 C for 4 minutes which reduced the moisture content of the treated fab rics to about 2-3 percent. The treated fabrics were analyzed and tested after washing. In addition to previously cited tests, the durable press ratings of the samples were determined after laundering and tumble drying by the procedure of the American Association of Textile Chemists and Colorists, AATCC Test Method l24l967 (AATCC Technical Manual, Volume 45, pages 181-2, 1969). Results are given in Table 111. Improved wrinkle resistance may be, achieved with as little as 0.5 percent of the catalyst in the treatment bath. ammonium chloride and phosphoric acid.

Table 11]- Fabric Properties Wr. Rec. Angle DP Catalyst Concentration, Break. str. (W+F). degrees Rating 71 kN (W), lb. Cond. Wet

Untreated 54.0 179 156 1.0

Example 5 For Sample 6C: 20 percent dimethylol hydroxyethyl Swatches of cotton printcloth were impregnated with solutions containing the following:

carbamate and 2 percent of an equimolar mixture of ammonium chloride and phosphoric acid.

The wet, impregnated fabrics weremildcured as in Example 3. Wrinkle resistance of the treatedfabrics was indicated by durable press appearance ratings. The

samples were rated for durable press appearance, by the standards of AATCC Test Method 124-1967 (op.

cit.), upon tumble-, line-, and drip-drying after laundering in an automatic (home-type) washing machine. The tabulated results are given in Table V and are compared with the ratings of untreated fabric.

Table V.

Durable Press Rating After Laundering and Sample Tumble-Drying Line-Drying Drip-Drying Untreated 1.0 1.0 l .0

This demonstrates the applicability of the catalyst system with hydroxyalkyl carbamate finishing agents.

Example 7 A swatch of 80 X 80 white cotton printcloth was impregnated with a solution containing 15 percent dimethylol isobutyl carbamate and 2.5 percent of an equimolar mixture of ammonium chloride and phosphoric acid. The wet, impregnated fabric was mild cured as in Example 4. The treated fabric after washing had a wrinkle recovery angle, conditioned (warp filling), of 263 and wrinkle-recovery angle, wet, of 247. This demonstrates the applicability of the catalyst system with alkyl carbamate finishing agents.

Example 8 A swatch of cotton printcloth was impregnated with a solution containing 15 percent dimethylol n-propyl carbamate and 2 percent of an equimolar mixture of ammonium chloride and phosphoric acid. The wet, impregnated fabric was mild cured as in Example 3. The wrinkle resistance of the treated fabric was indicated by a durable press appearance rating of 3.7 after laundering and tumble drying by the procedure of AATCC Test Method 124-1967. As in Example 7, the results demonstrate the applicability of the catalyst system with alkyl carbamate finishing agents.

Example 9 Swatches of cotton printcloth were impregnated with a solution containing 15 percent dimethylol methyl carbamate and 2 percent of an equimolar mixture of ammonium chloride and phosphoric acid. The wet, .impregnated fabrics were pinned on frames and mild' cured by heating in a forced air-circulation oven for various combinations of time (2-10 min.) and temperature (60l00 C), as detailed in Table VI. Properties produced by the various treatments, after washing also are given in the table. Table VI .These results demonstrate that high wrinkle resistance may be imparted to cotton fabric at mild curing temperatures as low as 80 C with heating times as little as 5 minutes.

Example 10 A solution was prepared comprising 7.5 parts dimethylol methyl carbamate, 1 part of an equimolar mixture of ammonium chloride and phosphoric acid, and 41.5 parts of water. Five grams of the solution was placed on a watch glass then placed in an oven at 100 C for 30 minutes. A tacky residue material weighing 0.6 grams remained on the watch glass. This residue was completely water soluble.

This demonstrates that noinsolubilization of a resin can occur in situ in fabrics when this finishing system is used.

Example 1 l A cotton printcloth was impregnated with a solution containing 15 percent dimethylol methyl carbamate and 2 percentof an equimolar mixture of ammonium chloride and phosphoric acid to obtain a wet pickup of aboutpercent. The fabric was heated at C for 2 minutes then a portion was washed and dried. A second portion was creased on a steam press then washed and dried, and a third portion was'creased on a steam press, mild cured 4 minutes at 100 C, then washed and.

dried. Results are givenin Table Vll.

Table Vll- Processing Step %N DP Rating Crease Rating I) Dried, washed L18 3.6 2) Dried,steam creased, 0.65 2.9 1.3

washed 3) Dried,steam creased. 1.12 4.4

4.9 m'ildcured, washed These results demonstrate the importance of the sequence of events in obtaining a creased fabric. Steam pressing is required to remove crosslinks as seen by drop in nitrogen content from step (1) to step (2) and mild curing is needed to reintroduce crosslinks in the shaped fabrics.

Example 12 A cotton printcloth was impregnated with a solution containing l5 percent dimethylol methyl carbamate and 2 percent of an equimolar mixture of ammonium chloride and phosphoric acid. The wet impregnated fabric was driedlminutes at 60 C. One portion (Sarnple 12A) of this fabric was washed and dried; a second portion (Sample 128) was wrapped in polyethylene,

stored one week, creased on a steam press, washed, and

Curing Conditions Fabric Properties 4 dried; a third portion (Sample 12C) was wrapped in polyethylene, stored one week, creased on a steam press, mild cured at 100 C for 2 minutes then washed and dried. Results are given in Table VIII.

Table VIII Sample WRA, W+F Crease %N 12A 202 0.05 128 200 l 0.30 12C 267 1.0]

Untreated I73 This demonstrates that the sequence of events is important even with a prolonged time period between initial heat treatment and creasing with the steam press.

Example 3 A cotton printcloth was impregnated'with a solution containing 15 percent dimethylol methyl carbamate and 2 percent of an equimolar mixture of ammonium chloride and phosphoric acid to obtain a wet pickup of about 90 percent. Portions of the wet impregnated fabric were dried to moisture contents of about 3 percent at C, 80 C, and 100 C then wrapped in polyethylene for 30 days. After the storage period the samples were creased on a steam press, mild cured at 100 C, 35

washed and dried. Results are seen in Table IX.

Table IX Results in FIG. 1 and Table IX demonstrate that although slow curing has occurred during storage (a serious problem encountered with sensitized fabrics using conventional catalysts) fabrics may be satisfactorily creased and mild cured at the low temperature of 100 C.

Example 14 A cotton twill fabric was impegnated with a solution containing 20 percent dimethylol methyl carbamate,

- 0.7 percent polyethylene softener, and 2.0 percent of an equimolar mixture of ammonium chloride and phosphoric acid to obtain a wet pickup of about. percent.

The wet impregnated fabric was divided into three se-.

ries and driedat 60 C on a tenter frame for 90, I20, and 180 seconds, respectively. A portion labelled Sample 14A of each dried fabric was then immediately washed and dried; another .portion, labelled Sample 14B, of each dried fabric was wrapped in polyethylene for 7 days then washed and dried; athird portion, labelled Sample 14C, of each dried fabric was stored 7 Dry Temperature Drying Time, Min. Curing Time, Min.

60 C 8 2 C 4 4 C 3 4 Crease Rating WRA, W+F

These results demonstrate the wide latitude in drying conditions operable before storage. High wrinkle resis tance and good creases are obtained after the storage period.

days, creased on a steam press, mild cured 2 minutes at 100 C, then washed and dried; a fourth portion, labelled Sample 14D, of each dried fabric was stored 30 days then washed and dried; and a fifth portion, la-

Additional cotton printcloths were treated but were 50 belled Sample 14E, of each dried fabric was stored 30 not creased by steam pressing and mild cured before washing and drying. FIG. 1 illustrates the effect of 30 days storage on wrinkle recovery change in the fabrics.

days, creased on a steam press, mild cured 2 minutes at 100 C, then washed and dried. Results are given in Table X.

Table X Drying Time, Storage Time, Mild Cure Time, Z Nitrogen WRA, W+F Crease Seconds Days Minutes I Ruling Sample I4A 90 0 O 0.23 I86 I20 0 O 0.29 I90 I80 0 O 0.35 189 Sample l4B Sam le l4C 90 7 4 I02 26! i 5 I20 7 4 1.05 264 5 I80 7 4 I03 263 5- Solutions. were prepared containing 15 percent dimethylol methyl carbamate and 2 percent catalyst. Each catalyst contained equimolar portions of ammonium chloride with the following acids; phosphoric acid, trichloroacetic acid, citric acid, tartaric acid, and oxalic acid. Each solution is identified in Table Xll.;

15 ,16 Table X-Coritinued Drying Time. Storage Time, Mild Cure Time. Nitrogen WRA, W+F' Crease Seconds Days Minutes Rating Sample l4D Untreated I60 From the results it is obvious that little change in Table Xll wrinkle resistance occurred in tenter drying times of 90 to 180 seconds at 60 C as seen for 14A samples. Slow Solution Catalyst Acid Used with NH Cl curing has occurred during storage as seen in Samples MMC 14A, I48 and 14D nitrogen and wrinkle recovery vallfiA l5 2 H,Po. ues. The substantial crosslinkage, as reflected in nitro- 'gg ClCHOriEJH gen and wrinkle recovery values increasing, has not, to l6D l5 '2 Tartaric our surprise, deterred development of effective creases 2 oxalic using a mild cure temperature of 100C as seen in Samples 14C f Swatches of cotton printcloth were impregnated by Example 15 each solution to obtain a wet pickup of about 90 percent. The wet impregnated fabrics were heated 12 min- A cotton twill fabric was impregnated with asolution Utes at 0 Each sample was the" Steam pressed containing 20 percent dlmethylolmethyl carbamate mild cured 2 minutes at C, washed and dried Percent Polyethylene softe'ferr and 2 percem of an Evaluation of the durable press performance is given in equimolar mixture of ammonium chloride and phos- Table XHL phoric acid to obtain a wet pickup of about 90 percent. The wet impregnated fabric was dried at 60 C for 3 Table xm minutes. A portion of the dried fabric was wrapped in polyethylene for storage. Another portion (Sample Solution Used lSA) of the dried fabric was washed and dried. A third On Fabric DP Rating Crease Rating portion (Sample 15B) of the dried fabric was creased 6A 4 O 5 on a steam press then mild cured 4 minutes at 100 C, m3 317 5 washed anddried. After storage of 90 days (3 months) :23 g the fabric in polyethylene was unwrapped and cut in 55 5 two portions. One portion (Sample l5C).was washed and dried, the other portion (Sample 15D) was creased on a steam press then mild cured 4 minutes at l00 C, The'effectwenesspfthe10W tempera? Catalys? washed and dried Results are given in Tab: XL tem is seen in the high DP and crease ratings obtained.

' V The wide applicability of acids compatible with ammo- Table Xl nium chloride is also demonstrated.

Sample Z Nitrogen lwai$$ l lin2r Crease Rating vExarnpk: 17 15A 0 30 I83 Cotton printcloth was impregnated with a solution 158 256 I 540 containing 15 percent dmiethylol dihydroxye- 15C 077 243 thyleneurea and 2 percent of amixture containing 2 257 moles ammonium chloride to one mole of tartaric acid,- said fabric, having a wet pickup of about 90 percent, was then dried for 7 minutes at C. Three portions Example 16 of the fabric were mild cured at 100 C. [Sample 17A for 2 minutes, Sample 178 for 4 minutes, and Sample 17C for 6 minutes] Three other portions were mild I cured at C [Sample 17D for 2 minutes, Sample 1713 for 3 minutes, and Sample 17F for 5 minutes] After washing and drying samples were evaluated for wrinkle resistance and tensile strength retention. Results are given in Table XIV.

Table XIV Time. Wrinkle Recovery Angle Breaking Strength Sample Temperature Minutes Warp Filling Retention, Warp l7A lOO C 2 240 70 17F l20 C 286 53 Untreated 100 These results demonstrate that a wide range of wrinkle resistance is obtainable at mild curing temperatures of 100 and 120 C.

Example 18 A 50/50 polyester/cotton blend fabric was impregnated with a solution containing percent dimethylol dihydroxyethyleneurea and 2 percent of an equimolar mixture of ammonium chloride and phosphoric acid. The fabric was dried on a tenter frame for 4 Va minutes at 65C. The treatedfabric was fabricated into a mans shirt by a housewife, ironed by her at a maximum iron temperature of 165 C then washed and dried. After 1 l wearings and washings the fabric still retains a smooth appearance.

This demonstrates the catalyst system with finishing agent is useful on textiles containing as little as 50 percent cellulosic fiber content, that the product is durable, and the utility for the home sewer.

Example 19 A cotton printcloth was impregnated with a solution containing 15 percent dimethylol dihydroxyethyleneurea and 2 percent of an equimolar mixture of ammonium chloride and phosphoric acid to obtain a wet pickup of about 90 percent and the fabric was dried for 7 minutes at 60 C.

One portion of the fabric, Sample 19A, was then Table XV Sample Durable Press After Crease Appearance After Tumble Drying Tumble Drying 19A 3.3 198 4.0 Very sharp 19C 4.0 Very sharp Samples 19B, and 19C demonstrate that the catalyst system is operative for home as well as commerical pressing operations.

Example 20 A cotton printcloth was impregnated with a solution containing 15 percent of the isopropoxy derivative of dimethylol dihydroxyethyleneurea and 2 percent of an equimolar mixture of ammonium chloride and phosphoric acid to obtain a wet pickup of about 100 percent.

' Oneportion (Sample 20A) of this fabric was heated for 7 minutes at 60 C and one portion (Sample 20B) was heated for 4 minuted at 100 C. Both samples were hand ironed using steam from the steam iron as a housewife does ironing in her home. Creases were produced in the warp, filling and bias direction during the steam ironing process. The steam was then cut off and each sample was ironed to dryness at a maximum temperature of 165 C. After washing and drying the samples, observation made on creases were very sharp for Sample 20A and sharp for Sample 20B.

These creases demonstrate the effectiveness of the mixed catalyst system which can be employed even on fabrics to be treated for the home sewer.

We claim:

1. A mild cure, cellulosic textile finishing process for imparting wrinkle resistance to a cellulosic fabric, comprising:

a. impregnating a cellulosic fabric, to a wet pickup of about from to percent, with an aqueous solution containing (1) as an agent for crosslinking cellulose, about from 5 to 35 percent of a formaldehyde-'carbamate adduct of the general formula where R is alkyl or hydroxyalkyl, and (2) as a catalyst for catalyzing the crosslinking reaction between the fabric cellulose and said crosslinking agent, about from 0.5 to 3.4 percent of a mixture consisting of ammonium chloride and an acid selected from the group consisting of phosphoric acid, citric acid, oxalic acid, tartaric acid, and trichloroacetic acid, where the molar ratio of the ammonium chloride to the acid ranges about from 1:2 to 2:1, and

b. heating the wet, impregnated fabric from step (a) for about from 1 to 6 minutes at a temperature of about from 80 C. to 100 C. to effect the crosslinking reaction between the fabric cellulose and the crosslinking agent while simultaneously reducing the moisture content of the fabric to about from 2 to 5 percent, thereby producing a wrinkle resistant fabric which, in its unwashed and un-neutralized state, is suitable for storage without suffering strength loss and which is addtionally suitable for further processing to impart desired shapes and creases.

2. The process of claim 1 wherein R is alkyl.

3. The process of claim 2 wherein R is methyl.

4. The process of claim 1 wherein R is hydroxyalkyl.

5. The process of claim 4 wherein R is hydroxyethyl.

6. The process of claim 1 wherein the acid is phosphoric acid.

7. The process of claim l'wherein the acid is citric acid.

8. The process of claim 1 wherein the acid is oxalic acid.

9. The process of claim I wherein the acid is tartaric acid. 2

10. The process of claim 1 wherein the acidis trichloroacetic acid.

11. A cellulosic textile finishing process for producing a durably creased and pressed cellulosic fabric, comprising: I

a. impregnating a cellulosic fabric,,to a wet pickup of about from 80 to 100 percent, with an aqueous solution containing (1) as an agent for crosslinking cellulose, about from to percent of a member selected from the group consisting of dimethylol methyl carbamate, dimethylol dihydroxyetliyl'eriurea, and isofiopoxymethyl dihydroxyethyleneurea, (2) as a catalyst forcatalyzing the crosslinking reaction between the fabric cellulose and said crosslinking agent, about from 0.5 to 3.4 percent of a mixture consisting of ammonium chloride and an acid selected from the group consisting of phosphoric acid, citric acid, oxalic acid, tartaric acid, and trichloroacetic acid, where the 1 molar ratio ofthe ammonium chloride to the acid ranges about from 1:2 to 2:1, and (3) about'from 0 to 0.7 percent of a polyethylene softener; b. heating the wet, impregnated fabric from step (a) for about from 1 to 12 minutes at a temperature of about from 60 C. to l00 C. to effect the crosslinking reaction between the fabric cellulose and the crosslinking agent while simultaneously reducing the moisture content of the fabric to about from 2 to 5 percent;

c. storing the crosslinked cellulosic fabric from step (b) for up to about 90 days;

d. converting the crosslinked cellulosic fabric from step (c) into a particular textile form;

e. steam pressing the crosslinked fabric from step (d) to remove the crosslinks and to crease and shape the fabric; and

f. curing the creased and shaped fabric from step (e) at a temperature of about from 100 C. to 120 C. for about from 2 to 4 minutes to reintroduce the crosslinks and to durably set the creases and the smooth, pressed appearance of the fabric.

12. The process of claim 11 wherein the crosslinking agent is dimethylol methylcarbamate.

13. The process of claim 11 wherein the crosslinking agent is dimethylol dihydroxyethylene urea.

14. The process of claim 11 wherein the crosslinking agent is isopropoxymethyl dihydroxyethyleneurea.

15. The process of claim 11 wherein the acid is phosphoric acid. I

16. The process of claim '11 wherein the acid is citric acid.

l The process of claim 11 wherein the acid is oxalic acid.

18. The process of claim 11 wherein the acid is tartaric acid.

19. The process of claim 11 wherein the acid is trichloroacetic acid.

20. A cellulosic textile finishing process for producing a durably creased and pressed cellulosic fabric,

comprising:

a. impregnating a cellulosic fabric, to a wet pickup of about percent, with an aqueous solution containing ('l) asan agent for crosslinking cellulose about 15 percent of a member selected from the group consisting of dimethylol methyl carbamate, dimethylol dihydroxyethyleneurea and isopropoxymethyl dihyroxyethyleneurea, (2) as a catalyst for catalyzing the crosslinking reaction between the fabric cellulose and said crosslinking agent, about 2 percent of an equimolar mixture of ammonium chloride and phosphoric acid;

' b. heating the wet, impregnated fabric from step (a) for about from 4 to 7 minutes at a temperature of about from 60 C. to 100 C. to effect the crosslinking reaction between the fabric cellulose and the crosslinking agent while simultaneously reducing the moixture content of the fabric to about from 2 to 5 percent;

0. storing the crosslinked fabric from step (b) for up to about 90 days;

d. converting the crosslinked cellulose fabric from step (c) into a particular textile form;

e. steam pressing the crosslinked fabric from step (d) with a home-type hand iron to remove the crosslinks and to crease and shape the fabric; and

f. curing the creased and shaped fabric from step (e) by dry-ironing with a home-type hand iron at a temperature not exceeding about C. for about from 2 to 4 minutes to reintroduce the crosslinks and to durably set the creases and the smooth, pressed appearance of the fabric.

Claims (19)

1. 2. The process of claim 1 wherein R is alkyl.
2. 3. The process of claim 2 wherein R is methyl.
3. 4. The process of claim 1 wherein R is hydroxyalkyl.
4. 5. The process of claim 4 wherein R is hydroxyethyl.
5. 6. The process of claim 1 wherein the acid is phosphoric acid.
6. 7. The process of claim 1 wherein the acid is citric acid.
7. 8. The process of claim 1 wherein the acid is oxalic acid.
8. 9. The process of claim 1 wherein the acid is tartaric acid.
9. 10. The process of claim 1 wherein the acid is trichloroacetic acid.
10. 11. A cellulosic textile finishing process for producing a durably creased and pressed cellulosic fabric, comprising: a. impregnating a cellulosic fabric, to a wet pickup of about from 80 to 100 percent, with an aqueous solution containing (1) as an agent for crosslinking cellulose, about from 10 to 20 percent of a member selected from the group consisting of dimethylol methyl carbamate, dimethylol dihydroxyethyleneurea, and isopropoxymethyl dihydroxyethyleneurea, (2) as a catalyst for catalyzing the crosslinking reaction between the fabric cellulose and said crosslinking agent, about from 0.5 to 3.4 percent of a mixture consisting of ammonium chloride and an acid selected from the group consisting of phosphoric acid, citric acid, oxalic acid, tartaric acid, and trichloroacetic acid, where the molar ratio of the ammonium chloride to the acid ranges about from 1:2 to 2:1, and (3) about from 0 to 0.7 percent of a polyethylene softener; b. heating the wet, impregnated fabric from step (a) for about from 1 to 12 minutes at a temperature of about from 60* C. to 100* C. to effect the crosslinking reaction between thE fabric cellulose and the crosslinking agent while simultaneously reducing the moisture content of the fabric to about from 2 to 5 percent; c. storing the crosslinked cellulosic fabric from step (b) for up to about 90 days; d. converting the crosslinked cellulosic fabric from step (c) into a particular textile form; e. steam pressing the crosslinked fabric from step (d) to remove the crosslinks and to crease and shape the fabric; and f. curing the creased and shaped fabric from step (e) at a temperature of about from 100* C. to 120* C. for about from 2 to 4 minutes to reintroduce the crosslinks and to durably set the creases and the smooth, pressed appearance of the fabric.
11. 12. The process of claim 11 wherein the crosslinking agent is dimethylol methyl carbamate.
12. 13. The process of claim 11 wherein the crosslinking agent is dimethylol dihydroxyethylene urea.
13. 14. The process of claim 11 wherein the crosslinking agent is isopropoxymethyl dihydroxyethyleneurea.
14. 15. The process of claim 11 wherein the acid is phosphoric acid.
15. 16. The process of claim 11 wherein the acid is citric acid.
16. 17. The process of claim 11 wherein the acid is oxalic acid.
17. 18. The process of claim 11 wherein the acid is tartaric acid.
18. 19. The process of claim 11 wherein the acid is trichloroacetic acid.
19. 20. A cellulosic textile finishing process for producing a durably creased and pressed cellulosic fabric, comprising: a. impregnating a cellulosic fabric, to a wet pickup of about 100 percent, with an aqueous solution containing (1) as an agent for crosslinking cellulose about 15 percent of a member selected from the group consisting of dimethylol methyl carbamate, dimethylol dihydroxyethyleneurea and isopropoxymethyl dihyroxyethyleneurea, (2) as a catalyst for catalyzing the crosslinking reaction between the fabric cellulose and said crosslinking agent, about 2 percent of an equimolar mixture of ammonium chloride and phosphoric acid; b. heating the wet, impregnated fabric from step (a) for about from 4 to 7 minutes at a temperature of about from 60* C. to 100* C. to effect the crosslinking reaction between the fabric cellulose and the crosslinking agent while simultaneously reducing the moixture content of the fabric to about from 2 to 5 percent; c. storing the crosslinked fabric from step (b) for up to about 90 days; d. converting the crosslinked cellulose fabric from step (c) into a particular textile form; e. steam pressing the crosslinked fabric from step (d) with a home-type hand iron to remove the crosslinks and to crease and shape the fabric; and f. curing the creased and shaped fabric from step (e) by dry-ironing with a home-type hand iron at a temperature not exceeding about 165* C. for about from 2 to 4 minutes to reintroduce the crosslinks and to durably set the creases and the smooth, pressed appearance of the fabric.