literature Cited (1) Am. Dyestuff Reptr. 38, 582 (1949). (2) Brennan, W. E., Zbid., 46, 583 (1957). (3) Coke, C. E., Can. Textile J . 73, 51-5 (June 29, 1956). (4) Coke, C. E., Textile Mf7. 77, 12-14 (January 1951). (5) Leventhal, H. L., A n . Dyestuff Reptr. 44,464-6 (1955). ( 6 ) Lovin, L. G., Wenzell, L. P., Ibid., 46, 326 (1957).
17) Moffett, R. P., Modern Textiles M a g . 37.62-5 (1956). ( 8 ) Ryan, 3. F.; A m . Dyestuj' Reptr. 40, 262 (1951). 19) Seymour, R. B., Zbid., 38, 453 (1949). (10) Shearer, H. E., Zbid., 41, 429 (1952). (11) Shearer, H. E., Symposium on Nonwoven Fabrics, Textile Sect., New York Board of Trade, January 28,1958. (12) Sherwood, N. H., A m . Dyestuj Reptr. 46, 323 (1957). (13) Taylor, J. T., Zbid.,46,437 11957).
(14) Wrotnowski, A. C., Chem. Eng. Progr. 53, 313 (1957). (15) Wrotnowski, A. C., Textile Research J.7,480 (1952).
RECEIVED for review February 18, 1959 ACCEPTED May 1, 1959 Division of Industrial and Engineering Chemistry, Symposium on Nonwoven Fabrics, 135th Meeting, ACS, Boston, Mass.. April 1959.
D. C. NICELY The Chemstrand Corp., Decatur, Ala.
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Nonwoven Fabrics Their Growing Importance to the Textile Industry
NONWOVEN
fabrics were pioneered by a few mills of the textile industry, and those mills are now among the leaders in the growing list of nonwoven producers. I n the first few years production of nonwovens was entirely in the hands of the textile industry, but today only about 35y0of the productive capacity for nonwoven fabrics is owned or controlled by companies whose interest is the conventional textile industry. About 307, of the productive capacity is controlled by companies whose major interest is something other than textile business. Almost 20% of the capacity is owned by independent interests. The textile industry has apparently relinquished leadership in the nonwoven field to others. In general the first nonwoven products were made of carded mill wastes held together with simple binders and were designed for disposable or nondurable end uses such as wiping cloths, sanitary products, etc. However, as quality standards were raised, more and more virgin fiber was consumed. This has been the trend in fiber consumption from almost exclusive mill wastes to virgin staple cellulosics and to considerable poundage of the higher priced synthetics : acrylics, polyamides, and polyesters. Similarly, as new binders with interesting characteristics emerged from the chemical laboratories, new fabrics have become realities, and the emphasis in development of new products has been pointed toward the durable type of product. There has been a change from simulated woven goods to engineered, bonded fiber sheets. Recently there has been development of bulky, lofty, resilient bonded fiber batts for specialized end uses. These new concepts are materials for which there is no counter part in woven or knitted goods. When apparel fabrics and home furnishing fabrics reach fruition in nonwoven form, finishing techniques now
910
employed in the textile industry or modifications required for specific cases will be of prime importance. Dyeing, brushing, napping, shearing, printing, and the variety of secondary treatments given to woven goods will undoubtedly be major factors in preparing nonwoven fabrics for the consumer market. Laboratory and development samples of skirting fabrics, blankets, jacket linings, and the like show promise of commercialization of these materials. However, the finest fabric produced will not yield profits unless it is styled and merchandised, and certainly the well organized merchandising departments of existing related textile companies may well be one of the keys to market acceptance of the new nonwoven fabrics. Certain properties of fabrics such as hand and drape are difficult to define and measure because of the intangible nature. They play a very important role in the commercial success of all fabrics. The trained operators in the textile business evaluate these properties and the st)lists are aware of the problems and demands of the market. The nonwoven producers affiliated with textile companies may utilize the functions of these merchandising groups. Textile fiber consumption in this country is about 6.5-billion pounds per year or some 35 to 40 pounds per capita. O n the basis of an estimated 90-million pounds per year of fiber used in nonwoven fabrics this represents a total usage of only about l1/,Y0 of all textile fibers consumed. In five years nonwovens might consume 370 of all textile fibers, and ultimately 5% of the fiber will go into nonwovens.
Impact o n Textile industry In many cases, the nonwoven products will complement orthodox textiles in the high-loft bonded fabrics which cannot be produced on conventional textile
INDUSTRIAL AND ENGINEERING CHEMISTRY
equipment, and other engineered fabrics tailored for specialized end uses. However, some volume might be lost from woven goods to the new nonwoven apparel, blanket, and home furnishing fabrics, on the basis of price or performance. Some synthetic fiber felts are available commercially and volume use is expected in the future. Nonwoven carpet constructions will be an interesting development. Aside from the normal growth curve of nonwovens expected, accelerated growth will result from technological breakthroughs in binder, fibers, web formation, and finishing. In the early days of nonwoven production, the basic line consisted of a series of cotton cards placed in tandem from w-hich a sandwich of full width webs was assembled for passage through a roll padder or discontinuous print bonding followed by dry cans and a windup. Later several organizations developed systems for the production of randomly oriented webs. About 60 of the mills in this country now use the random web process. One machine, Rando-Webber (Curlator Corp.), is commercially available. Garnetts with cross-lay equipment are in use as well as woolen cards for web production. Fibrous webs may be made in a wide range of weights, from an extremely fine gauzy web up to batts of two inches or more in thickness. A carded web has no appreciable strength or dimensional stability, and the binder added to the fiber imparts strength and other characteristics to the final fabric. In the initial phases of development nonwoven production lines were equipped with two-roll padders or resin printing devices. Now, the trend is to use wire screen saturators of either a single wire and drum type or the two double screen saturator. The single wire type is usually operated with a vacuum extraction system for removal of excess bonding liquor. Vacuum extraction is
NONWOVEN FABRICS
i
The Rando-Webber feeder 1.
Opener and tuft former 2. Elevating apron 3. Stripper apron 4. Air bridge 5. Feed material condenser screen 6. Roller conveyor 7. Air bridge fan 8. Trash chamber 9. Feed roll 10. Lickerin
not necessary with the double wire type, and in addition the double wire machine provides positive web control through the saturating operation. Another web stabilization system is the bonding method in which the binder is applied with an automatic horizontal reciprocating spraying machines. Fabrics made in this manner are characterized by resilience and very low density or high volume to weight ratio. This product is accepted for cushioning, padding, innerlinings, comforter, and filter materials, replacing conventional glazed waddings or garnetted batts in many applications. After saturation of the web or application of the binder by spraying the wet
11. 12. 13. 14. 15. 16. 17. 1 a. 19. 20.
Saber tube Condenser for forming Rando-web Adiustable duct cover Rando-web Webber fan Humidifier Creeping delivery apron Delivery conveyor Venturi Dust collection
web is dried and in case of a compounded binder is cured at an elevated temperature. Dry cans are used for drying the fabrics. The newer installations incorporate tunnel-type ovens of one, two, or three passes. T h e ovens are heated by steam, gas, oil, or electricity. Some resin cures may require temperatures as high as 350' to 400' F. Spray bonded webs are dried by radiant heat either from electric units or gas fired ceramic burners. Webs to be bonded with thermoplastic binders in powder or fiber form may be subjected to heat sufficient to melt the resin. Pressure may or may not be used concurrently with the application of heat.
Winders, slitters, and allied equipment may be installed downstream along with calenders and packaging facilities. How are these new and improved fabrics to be produced? I n the selection of fiber content there is a wide range of fiber lengths and deniers, fiber types: natural and synthetic, cellulosic, acrylic, polyamide, polyester, polyethylene, etc., fibers with high and low melting points, hydrophobic and hydrophilic, high and low chemical resistance, etc., and more new fibers in the offing. Certainly there is a large number of fibers to choose from and to use in fabric design. There are many binder types available on the market today-powders, fibers, solutions and emulsions, all of which have some desirable performance characteristics. Some systems other than water based may provide performance superior to that now obtainable. In web formation, new or modified fiber working machines may be developed to produce improved webs at higher production rates. Saturating units of the future will probably be designed to handle efficiently the expected bonding systems. The same applies to the drying equipment in that modifications might be required to handle toxic or hazardous vapors. I t is possible that existing finishing equipment might be used as installed, although there might be changes in settings or operational cycles. However, it is also possible that new finishing techniques may evolve concurrently with fabric development in order to exploit the unique properties of these materials. RECEIVED for review February 18, 1959 ACCEPTED May 1, 1959 Division of Industrial and Engineering Chemistry, Symposium on Nonwoven Fabrics, 135th Meeting, ACS, Boston, Mass., April 1959.
WILLARD E. CARLSON and KENNETH A. ARNOLD St. Regis Paper Co., Carthage, N. Y.
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Nonwoven Fabrics Their Growing Importance to the Paper Industry T
1 HE types of paper produced by the paper industry may be divided into production grades, which are usually of high volume and low unit profit, and into specialty grades, which are generally of much lower volume. Profits on pro-
duction grades are related closely to wood costs, paper machine speeds, and customer acceptability, coupled with efficient and sound business practices. Profits on specialty grades, however, are more closely related to the research and
development efforts that serve as the basis for the specialty, the equipment modifications, and know-how associated with production of uniform quality and customer acceptance. As specialty grades are usually premium priced, raw VOL. 51, NO. 8
AUGUST 1959
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