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Hydroxymethanesulfonic acid (HMS) is effective as a catalyst for durable-press finishing of cotton and polyester /cotton fabrics by pad-dry-cure, mild cure, and one-step dry-cure treatments. The catalyst is readily formed upon addition of sulfurous acid to pad baths containing free formaldehyde although it can be prepared separately. HMS is a strong acid and can be used in relatively small concentrations. The catalyst appears to be "self-limiting." It dissociates into volatile components during the curing treatment which makes afterwashing unnecessary to prevent changes in strength or wrinkle resistance.HMS catalysis of treatments with dimethylol methyl carbamate and formaldehyde crosslinking agents produced fabrics with high levels of durable-press properties. Mild-cure finishing at 100°C, and pad-dry-cure and one-step dry-cure finishing at 120-140°C were effective with this catalyst.

A study of the accelerated lightfading of dyes caused by wash-wear agents on cotton fabric showed that substituent groups on the agent could change the effect unpredictably. Hydroxyl substituents, however, always gave a slower rate of fading. A previous mechanistic theory for the phenomenon is incomplete, since at least two separate actions occur. One requires the presence of residues from the agent at the time of exposure to light so that they may participate in the photochemical reaction. The other is a sensitization of the dye by the agent during treatment and does not require the presence of agent at the time of exposure.

The relative acid and alkali stabilities of various nitrogenous finishes for cotton have been compared. The effect the groups attached to the carbonyl and the substituents on the amido nitrogen exert on the electron density of the amido group has been related to acid and alkali resistance.The finishes studied included those derived from urea. cyclic ureas, carbamates, and carhoxylic amides. In general, the groups exerting strong electron-attracting force on the amido group will increase the acid stability of the resulting finish and decrease the alkali resistance, and the groups which are strong electron donors increase the alkali stability and decrease the acid resistance.

Wrinkle resistance can be imparted to cotton fabrics with a diepoxide when certain coreactant curing agents are used. Such materials coreact to become a part of the finished product and introduce linkages and chemical groups which differ from those obtained when a true catalyst is used. Several coreactants including, for example. phthalic anhydride, citric acid, 1-aminoethyl-2-methyl-imidazoline, triethanolamine, and potassium thiocyanate, were used with 1,3-diglycidylglycerol as the diepoxide. In some cases mere deposition seemed to occur while in other cases cross-linkage was accom plished. Some indications of the types of reaction were obtained from infrared data and from the responses of the treated fabrics to various classes of dyes. In some cases coreaction between the diepoxide and the curing agent appeared to take place at rela tively low temperatures, producing improved wrinkle resistance. Phthalic anhydride was used to investigate this aspect in more detail.For comparison with the coreactant materials, several acid salts were used as catalysts, and the results are reported. Among the more suitable acid catalysts are magnesium perchlorate, aluminum sulfate, and zinc fluoborate.The inorganic acid catalysts produced fabrics with excellent durability and wrinkle resistance. Tearing strength losses, however, were greater with epoxide-treated cotton than those observed, at equivalent crease recovery angle, when a typical methylolamide finishing agent with catalyst was used. The durability to alkaline solutions of some of the epoxide finishes applied with coreactant curing agents was not as good as that of fabrics prepared with the inorganic acid catalysts. Tearing strength and wrinkle re sistance of epoxide-treated cotton can be improved by inclusion of additives such as polvethylene, acrylic polymer, or silicone, in the finishing bath.

The effects of cross-linking with dimethylol ethyleneurea on several etherified cotton fabrics—carboxymethylated, hydroxyethylated, methylated, and cyanoethylated cottons— were studied and compared with its effects on unmodified cotton. The effect of re placing cellulosic hydroxyl groups on the reactivity toward dimethylol ethyleneurea is dependent on the nature of the substituent and the swellability of the etherified fiber. Hydroxyethylated and methylated cottons exhibit greater cross-linking efficiency with dimethylol ethyleneurea than does unmodified cotton. High moisture regain in con junction with high wet and conditioned wrinkle recovery is possible with hydroxy ethylated cotton. Increased extensibility observed in etherified cottons is directly re lated to the alkali concentration used in the etherifying reaction. The rate of strength loss on cross-linking, with unit improvement in crease recovery, is greater for etherified cottons, except hydroxyethylated, than for unmodified cotton.

The cross-linking of cotton fabric with several N-methylol finishing agents in combi nation with an additive, the dimethyl ether of tetraethylene glycol, was investigated in an effort to obtain wrinkle-resistant and wash-wear cotton fabrics that retain an ability to swell with water. By proper adjustment of the concentration of this additive in the pad bath, it is possible to obtain finished fabrics with moisture regains equal to or even greater than untreated cotton, while maintaining good wrinkle resistance and wash-wear appearance.Wet crease recovery is slightly increased and dry crease recovery is slightly decreased by the use of the additive. Chlorine resistance and the relationship of breaking strength to crease recovery are unaffected.The inclusion of this additive in the treating bath formulation appears to alter hoth the length and distribution of the cross-links formed.

Alkali-soluble, fibrous cellulosic textile materials may be prepared by the oxidation of partially etherified cottons with nitrogen dioxide. Modified cottons bearing ether substituents, such as aminoethyl, carboxymethyl, carboxyethyl, methyl, α-methylcarboxy methyl, or phosphonomethyl groups, were readily oxidized to yield products with high alkali solubility.Using milder oxidation conditions than are required with native or mercerized cottons, products were prepared that are almost completely soluble in dilute sodium hydroxide or sodium carbonate solutions. The oxidation may be carried out with gaseous nitrogen dioxide or with organic solvent solutions of nitrogen dioxide.Variables of the process and properties of the products were investigated most ex tensively with partially carboxymethylated cotton.

the Southern Regional Research Laboratory has initiated work on the application of resin formulations to cotton garments for the express purpose of imparting permanent creases to them. In its full scope, the project has two phases: application to finished garments and application to yard goods, with resin curing in each case being accom plished on the finished garment. Advantages and disadyantages of the processes are described.Methods of application, procedures, and results are given for application of a dimethylol cyclic ethylene urea (CEU) formulation to swatches of fabric and to gar ments. Description is given of the effect of a numler of variables, such as the effect of storage on impregnated cloth, possibilities of stripping, precautions in drying and curing, durability to laundering, effect of sizing, effect of catalysts, and results using related resins in varying the formulation.Ultimate objectives are given including cooperative work with other research agencies to utilize standard drycleaning equipment for commercial application, use on yard goods, and development of non-chlorine-retentive finishes suitable for white goods in imparting permanent creases to cotton garments.

Many cellulose derivatives are known to be water- or alkali-soluble, The solubility of these derivatives which are principally esters and ethers has been found to be a func tion of the degree of polymerization, the nature of the substituent group, decree of substi tution, method of preparation, and type of solvent. A few soluble fibers have been pre pared from cotton in which the fibrous form of the cotton is retained during the prepa ration; that is, the cellulosic hydroxyl group has been chemically modified to a group which confers solubility to the fiber. Hydroxyethylation. carboxymethylation, and oxi dation are examples of such procedures and details of the processes are given.Factors affecting the solubility of chemccally modified cotton are discussed. Among these are the mechanism of solution of a modified fiber; and the problems of uniformity of treatment encountered in the chemical modification of cotton fiber, yarns, and fabric.Some of the present uses of soluble fibers and possible future uses are discussed.

Cyanoethylated cotton has been subjected to treatment with excess 1% aqueous sodium hydroxide at temperatures of 22°, 60°, and 97° C. Rates of cleavage of cyanoethyl groups at these temperatures have been determined. Resistance to rotting is destroyed by re moval of part of the cyanoethyl groups. Heat resistance is decreased by the alkaline treatment, but only to the extent that nitrogen is removed. It appears that heat resistance is directly proportional to the nitrogen content regardless of the previous history of the sample. Dyeing characteristics, measured by a differential staining technique, show reversion to the color of untreated cotton even though only half the nitrogen is removed.Physical properties are not adversely affected by alkaline hydrolysis. Tenacity in creases as groups are cleaved but does not return to the original value of the gray yarn. This is the usual case with other cellulose derivatives. The knot strength data do not indicate brittleness. Hydrolysis has little effect on elongation.

Fluorine and iodine compounds, both organic and inorganic, were tested as flame retardants for cotton. Comparison with bromine and chlorine compounds showed that the effectiveness of the halogens, on an equal weight basis, increases in the order. fluorine, chlorine, bromine, iodine, with the last two about equally effective.

The effect of laundering, mercerizing, and simulated vat dyeing on the properties of partially cyanoethylated cotton was investigated. Cotton sheeting cyanoethylated to various nitrogen contents, from 2.2 to 6.4%, was subjected to laundering, mercerizing, or simulated vat dyeing. The samples were then analyzed for thread count, weight, and thickness and tested for breaking strength, elongation, tearing strength, abrasion resistance, air permeability, stiffness, moisture regain, heat resistance, and rot resistance. In addition, wrinkle recovery of the partially cyanoethylated and untreated cloth was determined.Results of the study indicate that neither laundering, mercerizing, nor simulated vat dyeing seriously affects the usual textile properties of partially cyanoethylated cotton. The rot resistance and heat resistance of samples of more than 4% nitrogen content were not greatly impaired by these treatments; however, a sample of 3.2% N was not rot- resistant after these subsequent treatments.

A combination of two existing flame retardants, THPC and the bromoform-triallyl phosphate polymer, produces a flame-retardant finish for cotton which is superior to that of either finish alone. Fabrics 8 oz. or heavier are made highly flame-resistant. The finish is durable and employs a single treating bath with a simple finishing procedure.

A number of the textile and chemical properties of cotton reacted with β-propiolactone have been investigated and are reported. Differences in the properties of the products of the reflux and of the alkali methods of treatment are shown.Reaction of cotton with β-propiolactone yields a cellulose derivative with a bound graft polymer. The results of this unusual reaction are shown by optical means with micro scopic cross sections and electron micrographs, by changes in X-ray diffraction patterns, by influence on textile properties, by chemical effects such as saponification to yield car boxyethylcellulose, and by the production of unsaturation in the cellulose derivative.

Water- and alkali-soluble cotton fibers, yarns, and threads have been prepared by two methods. The cotton is preferably pretreated by pressure-kiering in 2% sodium hydroxide to remove the noncellulosic materials, and then treated with monochloroacetic acid and sodium hydroxide by either a one-step or a two-step process. Where only disintegration or partial solubility is required, the one-step method is sufficient. Where complete solubility of the cot ton is required, the process must be carried out in two steps: a mild, followed by a stronger treatment. The treated cotton is neutralized in alcohol with acetic acid to produce water soluble products or with strong acids in alcohol to produce water-insoluble but alkali-soluble products. Cotton in the form of sliver, yarn, and thread has been successfully treated.

The prevention of the acid degradation of industrial cotton fabrics is a problem of considerable importance, since such degradation often causes serious financial loss. Some data gathered during an investigation of a special phase of the acid hydrolysis which occurs in the cotton sewing thread used to sew paper bags for certain types of fertilizer may prove of help in the eventual solution of the problem.

Additional studies have been made on partial carboxymethylation—the reaction between mono chloroacetic acid and cotton in the presence of sodium hydroxide—and on the products ob tained. A thorough investigation of the time and temperature of reaction and concentration of reagents showed that relatively small amounts of monochloroacetic acid, properly applied, alter the properties of cotton considerably.Pilot-scale carboxymethylation of cloth was conducted which showed that it is possible to use standard textile machinery in the process. The cloth resulting from this treatment had a crisp liand with a slightly starched feel.More detailed investigations than reported previously were made, and it was found that the tensile strength and elongation of treated cotton are increased, dyeing properties are changed, and soiling-resistance and soil removal are increased. It was also learned that the treated materials are unaffected after one year's storage.

A method of applying resin treatments to the acid form of partially carboxymethylated cot ton cloth to produce crease-resistance has been developed. The acidity of the carboxyl group and the higher swellability are advantageous for overcoming two difficulties met in the usual methods of producing crease-resistant cotton cloth by resin treatment. The presence of the acid carboxyl group supplies a built-in catalyst, making the addition of catalyst unnecessary, in this way avoiding the prepolymerization of resin baths which contain added catalysts. The high swellability of the modified cotton allows easier penetration of the resin-formers and larger pickup of resin, with the production of cloth of equivalent crease-resistance, of superior hand and abra sion-resistance, and better in most other physical properties, in comparison with the unmodified resin-treated cloth.The process of carboxymethylation, which consists of impregnating cotton cloth with a weak solution of monochloroacetic acid followed by treatment with strong sodium hydroxide, is com mercially feasible and can be carried out on ordinary textile equipment.

β-Propiolactone was reacted with purified cotton in the presence of organic solvents. The reaction was found to be affected by time, temperature, and concentration of reagents. Weight gains of upwards of 60% were obtained.In all reactions of purified cotton with β-propiolactone in organic solvents, etherification oc curs, apparently followed by polyesterification of the attached groups by additional lactone. At tempts to direct the reaction towards either etherification or esterification by means of acid and base catalysis were not successful.Increases in the extent of reaction were obtained by "activation" of purified cotton with acetic acid prior to the treatments with β-propiolactone.

The reaction of cotton cellulose with β-propiolactone may be effected in the presence of strong alkalies such as sodium hydroxide and potassium hydroxide. Monoethanol amine and trimethylbenzyl ammonium hydroxide will also catalyze the reaction, but to a lesser degree. Di- and triethanolamine are ineffective. Byproducts of the reaction are water soluble and may be removed with a hot-water wash.Conditions of the reaction such as time, temperature, concentration of reagents, and effect of diluents were investigated and are reported.The products are mixed ethers and esters of cellulose and polyesters thereof, in fibrous form. The ether linkages are stable to saponification, while the ester linkages are broken. Therefore, saponification removes all but the carboxyethyl groups attached directly to the cellulose molecule.

The preparation of partially cyanoethylated cotton with acrylonitrile in the presence of sodium hydroxide is described, including effects of changes in time, temperature, and concentration of reagents. Products with retention of the fibrous form have been ob tained with degrees of substitution up to 2.7 cyanoethyl groups per anhydroglucose unit.Hydrolysis of the cyanoethyl group occurs readily under alkaline conditions and re sults in both cleavage and conversion to the carboxyethyl group. Maximum conversion in the latter case was 29%.

Flame-resistant cotton fabrics have been prepared by treatment of the fabric with an aqueous emulsion of an organic polymer, prepared from bromoform and triallyl phosphate. The finish is durable to repeated laundering, and when applied with proper plasticization to fabrics of 8-9-oz weight does not materially change other textile properties. The treatment may be applied on conventional textile finishing equipment.

The mechanism of cyanoethylation of cotton is discussed, and it is shown that for best effi ciency the pick-up of sodium hydroxide must not exceed 15% of the weight of the cotton. Measurements of physical properties show that any increases in the breaking strength or elon gation of yarns are results of changes in frictional forces. The physical properties of cyano ethylated fabrics reflect the properties of the yarn and are also dependent on fabric construction. Extremely high resistance to flat abrasion is obtained with high cyanoethyl substitution.The density of cyanoethylated cotton is shown to be linearly related to the nitrogen content, and the spread of values obtained has been found to give an estimate of the uniformity of treatment.Cyanoethylated cotton can be dyed by methods developed for polyacrylonitrile fibers such as those employing acid dyes in the presence of cuprous ion, and the dyed samples so produced are suitable for cross sectioning for microscopic examination. The intensity of dye color can be used as a measure of the amount of cyanoethylation.

The cross-linking of cellulose in cotton fabric with three wrinkle-resistance finishing agents has been investigated. The three agents used were dimethylol urea, dimethylol ethyleneurea, and formaldehyde. With all three compounds, maximum crease recovery angles are obtained with a substitution of 0.04-0.05 cross links per anhydroglucose unit. As crease recovery angles increase, the elongation and permanent set caused by an 8-kg. tensile load on a 1-in. fabric strip decreases. Permanent set approaches zero near 135° warp crease recovery. Changes in the load-elongation curves indicate elastic modulus increases as crease recovery angles increase. Treatment of fabric to the same crease recovery angles with the three compounds reduces tearing and breaking strengths to different extents. The differences are due to different amounts of cellulose degradation caused by the aciclic catalyst systems and not to the structure of the cross links.

For the purpose of obtaining quickly swellable fibers to aid in making cloth less pervious to water, cotton fibers have been partially carboxymethylated. Different degrees of swelling have been obtained and the properties of the resulting products are described.

The effects of cross-linking cotton stretch fabrics with dimethylol ethyleneurea have been studied. Results are similar to those obtained with ordinary cotton; that is, the stretch cloth, after cross-linking, has wash–wear and wrinkle resistance properties but loses in tearing and breaking strength. The amount of add-on governs strength loss, and in practical use it must be balanced against the degree of wash–wear improvement desired.Stretchability of the fabric is not greatly lowered by cross-linking. The effect of prolonged stretching on size and on shape, measured as growth, is reduced by cross-linking, but washing is essential for recovery. Under conditions of repeated stretching without washing, permanent set, immediate recovery, and delayed resiliency are affected very little by cross-linking.

Stearamidomethylpyridinium chloride reacts with cellulosic hydroxyl groups to produce a stear amidomethyl ether of cellulose. Substitutions of 1 stearamidomethyl group per 150 anhydro glucose units have been obtained. The permanent water-repellency obtained on treatment of cotton fabrics with amidomethylpyridinium salts is due to this reaction.

Cotton can be etherified by treatment with chloroacetic acid and sodium hydroxide solution. The product, a partially carboxymethylated cotton, which retains the original fibrous nature of the cotton, has a number of properties valuable for textile and other uses. In addition, the etherified cotton bears two reactive functional groups—hydroxyl and carboxyl—capable of further chemical modification.The rate and extent of many reactions with the etherified cotton are greater than with native cotton similarly treated. Further modifications of this cotton derivative are discussed. Among these are salt formation for the preparation of bactericidal and fungistatic finishes, reactions for the introduction of cyanoethyl, carboxyethyl, and graft polyester groups, reaction with epoxy and aziridinyl compounds, and oxidation for the preparation of alkali-soluble textile products.

A study has been made of the mechanism by which cotton is made wrinkle resistant by dimethylol ethyleneurea. Estimates are made of the length of cross-links and the relative effect of several factors, including processing conditions, cross-linkage, and acid damage, on the loss in strength of the fabric on treatment. 'Various methylol derivatives of ethyleneurea were used in the study of the effect on chemical and physical properties. It has been demonstrated that the methylol deriva tives of ethyleneurea react chemically with cellulose under the influence of acidic catalysts. Metallic salts are most efficient in promoting this reaction. Both mono functional and difunctional compounds react with the cellulose. The latter, however, cause cross-linkage, which effects marked changes in the physical properties of the treated cotton fabric, particularly wrinkle resistance. Dimethylol ethyleneurea forms cross-links averaging 1.4-1.5 ethyleneurea residues in length. These residues are con nected by methylene groups. The effects of variations in catalyst, composition of the finishing agent, and curing conditions are shown. Relation of the findings to practical finishing is discussed.

Research is under way at the Southern Regional Research Laboratory to improve cotton by resin treatment to strengthen its competitive position with respect to other fibers. In preliminary stages of the work, garments were finished using improved formulations and improved methods of curing which yielded garments which are truly wash and wear in that they may be machine laundered, dried, and worn without ironing. Attention is now being concentrated on attempting to perfect a finish aimed particularly at men's "no muss" summer weight dress cotton suits and slacks, an 180 million square yard per year market of which cotton now holds only about 11%.In the phase of the work reported here, both fundamental and practical studies have been conducted on a "recuring" process, proposed by the National Cotton Council of America, in which cotton goods, already treated with resin and cured, are made into garments and aftercured by careful introduction of catalyst. The creases, pleats, cuffs, and so forth are then set by heat curing. Creases so introduced are not as durable to laundering as those which can be set in the fabric on an initial cure, but they compare favorably with those found in worsted wool garments. Two possible mechanisms for the recuring process are suggested and evidence in favor of each hypothesis is given. Results on the recuring of both laboratory and commercially resin-treated cotton fabrics are reported.

Cotton fiber, thread, and fabric were carboxymethylated by a nonaqueous process. Activated cotton was impregnated with an isopropanol solution of monochloroacetic acid and refluxed with 0.3% sodium hydroxide in a mixture of methanol and isopropanol. Degrees of substitution ranging up to 0.09 were achieved. Higher values can be ob tained by retreatment or premercerization.Four varieties of cotton fiber have been carboxymethylated by this method. Cor relation between the reactivity and the original physical properties of the fibers has been shown.Textile properties of fabric treated by this nonaqueous method and those of a sample treated by the usual aqueous alkali method were compared at equal substitution. The α-methyl-, α-ethyl-, α-propyl-, α-decyl-, and α-cetylcarboxymethyl derivatives of cotton were prepared in low degrees of substitution, using the appropriate α-halo carboxylic acid as etherifying agent in the nonaqueous reaction.

It was found that phosphorylated cotton cellulose made by the phosphoric acid-urea method has a high cation-exchange capacity and when used in the form of a coarse fabric it shows good now characteristics in the calcium-hydrogen cycle. Its cation-exchange capacity increases with increasing phosphorus content and at a phosphorus content of about 5 percent the cation- exchange capacity reaches about 1,000 milliequivalents per kilogram. It is possible that specialized uses may be found for phosphorylated cotton cellulose, especially in the fabric form.

The literature relating to the water-repellency of textile materials has been surveyed for those articles and patents dealing with the production of this property by chemical methods. The 332 pertinent references found have been abstracted and classified on the basis of the type of compound used to impart water-repellency. No attempt has been made at critical evaluation. Reactions, where known, have been described with the aid of equations. Additional references for collateral reading are given. An index which has been compiled of the chemical water-repellent agents proposed is being published by the U. S. Department of Agriculture as Research Publication AIC—179.

Reports in the public press have confused the two types of soluble yarns produced in the Southern Regional Research Laboratory. This letter differentiates between the alkali-soluble metal carboxymethylcellulose fibers previously described and the new water- or alkali-soluble modified cotton yarns. A typical method of preparation is described.

Methanesulfonic acid, because of its similarity to hydroxymethanesulfonic acid, has been investigated as a catalyst for finishing cotton to produce durable-press properties. It provides strong catalysis in mild cure and conventional pad- dry-cure treatments. However, fabric must be washed after treatment to remove residual acidity which otherwise causes undesirable changes in the finish.