Textiles ALFRED E. BROWN and JOHN F. KRASNY Harris Research Laboratories, Inc., Washington 1 1 , D. C.
IN 1958, resin treatments of cotton for "wash-and-wear," the predominant use of chemicals in textile finishing today, have been applied to 2 billion yards of cotton goods, or approximately 2 0 % of the cotton used for apparel goods. This represents an increase of about 4 0 % over 1957, with further growth clearly indicated as the field of wash-and-wear expands to encompass work clothing and "easy care" sheets. Similar growth rates can be observed with the fully synthetic fibers. Nylon, the chemist's first synthetic fiber creation, celebrated its 20th birthday with a productive capacity in the U. S. alone of 350,000,000· pounds annually. Acrylic fibers, commercially developed only about 10 years ago, are being produced at a rate of about 200,000,000 pounds annually. The production of Du Pont's polyester fiber Dacron is slated to be 100,000,000 pounds in 1959, and this will be supplemented by capacity from three additional companies introducing their own versions of polyester fibers. Some of this expansion may be temporary overcapacity, but it testifies to the confidence of the chemical industry in the long-range potentialities of these synthetics. On the other hand, production of the regenerated cellulosic fibers has not expanded in the U. S., but other countries with expanding industrialization, such as Russia, are increasing their capacity for producing such fibers. This confidence in synthetics is backed u p by constant research to improve certain deficiencies associated with these fibers. Thus, the synthetics, in varying degrees, suffer from poor dyeability compared to cellulosic fibers, poor bulk compared to wool, low moisture absorption which is associated with poor comfort characteristics, excessive soiling especially by oil-borne soil, pilling, low melting point, and relatively high price. However, technical developments, designed to overcome
some of these deficiencies, continued unabated. First, and already realized on at least one commercial fiber, is the grafting of dye-receptive or hydrophilic groups onto one of the high-strength backbones such as acrylics or polypropylene. Entirely new fiber types—e.g., phenolformaldehyde, cross-linked polyurethane—were formed by chemical reaction of the polymer after extrusion ; other experiments were directed toward fibers with superior heat and chemical resistance, as from materials such as polymethylene sulfone. Polymerization of nylon at solution interfaces rather than in the melt, for example, was reported to result in better process control and a product with higher molecular weight. High-strength silica fibers which can be coated with metal have heat resistance exceeding that of glass. Following its introduction in Italy some years ago, polypropylene yarn production has been started in the U. S. The first applications seem to be in ropes and filters, with carpets, upholstery, and apparel to follow. A pilot plant for poly(vinyl alcohol) fibers, to be produced under Japanese license, will be built in the near future. Several companies have developed elastomer yarns to compete with natural rubber to use in bathing suits and foundation garments; the advantages are high strength and good resistance to dry cleaning and laundering. To improve their competitive positions, the manufacturers of existing fibers are expanding into new types "tailor made" for specific requirements. New viscose types include cross-linked, crimped staples for blending with wool and synthetics, higher strength staples for industrial uses and cotton blends, and special types for carpets, for upholstery (which crimp in bleaching and dyeing), and for filters. A new Dacron type is said to give better blending with wool, and a new
nylon with cotton. A special acrylic fiber for blanket manufacture has been announced. Production has been expanded of the lesser known monofils, such as polystyrene, acrylonitrile-styrene, and vinyl chlorideacetate, which are used for specific purposes. 1958 has also seen a great deal of activity in regard to the historic standards of the textile industry— namely, cotton and wool. Resin treatments, including the magic wash-and-wear fabrics, may have consumed as much as 80,000,000 pounds of chemicals during the year, with many chemical products competing in this growing market. Extensive research and development activities, both in Government and in industry, have produced a flood of treatments. Products now used in commercial quantities include, beside the well established urea-formaldehyde, melamine-formaldehyde, and cyclic ethylene-urea compounds, acetals, epoxies in blends with cyclic ethylene-urea, triazines, and triazones. Still experimental, and pricewise probably noncompetitive but reportedly excellent for this purpose, is tris-(l-aziridinyl)phosphine oxide (APO), which has been found to be also a good flameproofing agent. Continuing research in this field is designed toward better appearance of the fabrics after laundering and after daily wear; better durability to laundering; better processing economy; extension of wash and wear to rayon; reduction of the change in the elastic properties of the fibers (which reduces wear life) ; VOL. 5 1 , NO. 1
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elimination of chlorine retention during laundering (which damages and yellows the fabric) ; search for the most appropriate additives to the resin finish, such as softeners and surface resins (both of which are suspected of increasing the susceptibility to soiling) ; prevention of odor formation due to formaldehyde; and last but not least, a better understanding of the mechanism involved in the cross-linking reaction, to impart to cellulosic fibers optimum resilience both dry or wet, with minimum deleterious effects on breaking and tearing strengths. An interesting development, probably somewhat removed from practical use, concerned the reaction of amino groups in aminized cotton with iV-acetyl-D,L-homocysteine thiolactone to introduce sulfhydryl groups capable of forming dissulfide bonds between cellulose chains. Thus, certain fibers are still being modified to develop the desirable attributes of other fibers. Wool itself, now clearly surpassed in U. S. consumption by synthetics, stimulated a great deal of interest in 1958 with the introduction of the Siroset process, developed by research scientists in Australian Government Laboratories. In this process, ammonium thiogylcolate is used to impart permanent creases and pleats to wool fabrics during garment pressing operations. The process is now being used commercially both in Australia and in England, and is being explored in America. Dieldrin has also been used extensively in the U. S. during the past year to mothproof wool. Other finishes have made smaller, but still important progress. New silicones with better resistance to wet soiling and high temperature laundering and dry cleaning (one is an "epoxyorganosiloxane") were announced. Germ killers are now offered on carpet pads, yard goods, linings, and pillow cases. These products are based on chemicals such as hexachlorophene, o-phenylphcnol, quaternary ammonium salts, and mercurial compounds, and experimentation with antibiotics is under way. The main problems encountered are toxicity, instability in use, especially in laundering and dry cleaning, and incompatibility with other finishes and dyes. A new suspending agent for printing, a carboxyvinyl polymer, has
I/EC ANNUAL REVIEW been announced, to compete with starch and other products. On the other hand, starch products specifically designed for synthetic fiber sizing (a market held by gelatin and resins) have been developed. Interest in agents to prevent soiling of carpets and apparel by both water-and oil-borne soil, and in durable antistatic agents, continues. A catechol-formaldehyde treatment was reported to improve nylon's resistance to sunlight. A new Dacron to rubber adhesive (an aqueous solution of phenol-blocked isocyanate in combination with latex) permits use of this fiber in industrial uses where its low creep and high modulus are desirable, such as V-belts and coated fabrics for blimps. The versatility that chemical treatments lend to one fiber is best shown by a promotional exhibit by a British finisher, consisting of samples of a nylon taffeta which acquired a dozen different characteristics due to the finish: soft, absorbent for shirtings; semistiff, pliable, for foundation garments; delustered for lingerie; paper taffeta "crinoline" for petticoats; washable, antistatic finish for ladies' overalls; silicone-proofed for linings and rainwear; pebble-embossed for blouses and nightwear; permanently glazed for down-proof linings; antimildew finish for sailcloth; colored emboss for children's wear; antiodor and antiperspiration finish for corset cloth; fast colors, proofed for umbrellas and swim wear; dimensionally stable flat finish for coating, oiling, and rubberizing. Fiber-reinforced plastics have become of interest for nose cones for missiles, where demands are made for unprecedented heat and stress resistance and for lack of distortion of radio signals. Here phenolic resins reinforced with nylon and asbestos were found to be better than asbestos alone or glass. Also desirable were structures prepared by the deposition of polymers from aqueous solution on Teflon fibers. Competition among cotton, glass, synthetics, rayon, sisal, paper, and metal fibers remains keen for the reinforced plastics market. In the dyeing field, there is almost a race between the fiber producers
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to perfect synthetic fibers with dyeing properties similar to those of the hydrophilic fibers, and the dye manufacturers to perfect dyes and dyeing processes which make this unnecessary. A new, experimental class of dyes for nylon, Orion, and Dacron, based on percyano-olefins, is an example. Pretreatment of acrylic fibers with hydroxylamine sulfate or chloride is reported to improve their dyeability. Nor has interest in improved dyeing of the cellulosic fibers slackened. The pad steaming dyeing method and the use of solvents such as n-butyl alcohol with small amounts of water, applicable to a wide variety of dyes, are seen as steps toward greater efficiency, with elimination of aqueous dyeing baths as the goal. Dyes which react with cotton or wool via covalent cross linkages have been developed, as it now is possible to protect the fibers from damage during the application. Thus the market for chemicals in the textile industry continues to increase with both the growth of synthetics and the chemical finishing of natural fibers. Oftentimes there will be increased use of chemicals in one area, accompanied by a decrease in use in another—for example, as nylon replaces rayon in the automobile replacement tire field. Similarly, the answers to questions such as the following will influence the consumption of chemicals in the textile industry: Will the increasing popularity of wash-and-wear garments hurt the growing ($85,000,000 annual) drycleaning solvent and chemical specialty market, or alter the chlorine household bleach market, estimated at 600,000,000 quarts, and thereby aid the peroxy bleach market? How will the advance of nonwoven fabrics, which need binders and special softeners, affect the consumption of woven and knitted fabrics? How many textiles will be replaced by specially treated paper in such uses as sandbags and disposable garments? Regardless of how these questions are answered, the future for the chemical industry looks bright, as it finds the textile industry an expanding customer for a wide variety of chemical products. VOL. 5 1 , NO. 1
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