C&EN A N N U A L
REVIEW—!951
Activity continues ot on accelerated pace with problems of production and end use becoming increasingly important in the field o f
Textile ChenrtlcoS Development M I L T O N KARRIS A N D A N T H O N Y M . S C H W A R T Z Harris Research Laboratories, Washington, D. G
X H E year 1951 marks the fiftieth anniversary of t h e introduction of chemically made fibers in the United States, a n d during this year the production of such fibers reached a total of 1.5 billion pounds. A major part of this volume is accounted for by the cellulosic fibers, viscose, acetate and cuprammoniiim, but predictions have been advanced that the production of the newer noncellulosic fibers such as Vicara, Dacron, Dynel, Orion, and Acrilan will reach 1 billion pounds annually b y 1960. Such development will profoundly affect the dyeing and chemical finishing practices throughout a large segment of the industry, particularly as related to goods m a d e from these fibers. Furthermore, the potential for new synthetic fibers may unbalance the existing supplies of raw materials, and at least one newer fiber awaits increased production of raw material in o r d e r to meet existing demands. T h e major problem of textile fabrication, however, remains that of selecting the right fiber or combination of fibers for a given end use. E n d use evaluation in terms of t h e chemical as well as mechanical properties is being more carefully scrutinized, and in this re-examination t h e older fibers as well as the n e w ones have n e w t r i u m p h s . T h e decision of t h e military establishment to consider blends of wool w i t h synthetic fibers such as nylon, Dacron, a n d the acrylic fibers for uniform fabrics is of particular interest in this connection. O n the o t h e r h a n d , the Air Force has successfully tested cargo parachutes of cotton, said to cost one quarter as m u c h as the standard nylon chute. Synthetic Fibers Activity in the synthetic fiber field h a s c o n t i n u e d at an accelerated p a c e with problems of production a n d end utilization becoming increasingly important. Dacron, t h e U. S. version of the British polyethylene terephthalate fiber, Terylene, is n e a r i n g full scale production a n d 16
Acrilan, Chemstrand's acrylonitrile fiber, is scheduled to attain a 30-million-pound production capacity during t h e coming year. T h e C h e m s t r a n d Corp. h a s also become the first domestic licensee to produce nylon. The growth of the acrylonitrile fiber industry is indicated in a forecast that by 1952 it will be the largest single consumer of cyanide. It is known t h a t several other acrylonitrile fibers, polymers or copolymers, are being actively developed, and n e w methods for producing the monomer from acetylene are being explored. Increased production of Vicara, Virginia-Carolina's protein fiber, is awaiting expanded facilities for Zein preparation. Among newcomers in the synthetic field are Algil, produced by Polymers, Inc., a polystyrene fiber of unusual fineness, characterized by its low density and complete resistance to acids and alkalies. In batting form it is stated to be an excellent filtering medium for air and gases. A low denier saran staple is being introduced for use in carpets. Inherent llame resistance as well as resistance to biological agents is claimed, together with a pleasing lustrous appearance. Foreign manufacturers have also introduced several new synthetic fibers during the past year. Phrilon, produced in Germany, is stated to b e a true nylon type, and will b e competitive w i t h the well established Perlon which is based on aminocaprolactam. Manufacture of another aminocaprolactam fiber to be called Mirlon has been started in Switzerland. IG Farben is developing an acrylonitrilebased product to b e called Tanfiber. A new type of wet-spun polyvinyl chloride fiber is being introduced u n d e r the name PCU to supplement the older dry-spun P C fiber. T h e Japanese fiber Vinylon, which is m a d e by spinning a polyvinyl alcohol and subsequently hardening, is reaching a production rate of 10 million pounds annually. In the protein fiber C H E M I C A L
field, ArdiL based o n peanut protein, has been launched in E n g l a n d and is expected to reach a 20-million-pound annual rate within t h e coming year. Caspian a, t h e D u t c h casein fiber, is again in production, the plant where it w a s first m a d e before the war having b e e n reactivated. Cellulosic Fibers Research on c o t t o n a n d natural cellulose fibers has continued to emphasize chemical modification a n d finishing treatmentsT h e controlled reaction of cotton with formaldehyde is said to produce increased resistance to microorganisms, decreased swelling, and g r e a t e r light fastness of a p plied dyestuffs. Blocking of aldehyde e n d groups b y reaction with methanol p r o duces low-viscosity celluloses w h i c h are unusually resistant to further action of alkalies. T r e a t m e n t s which include t h e introduction of a c e t y l , carboxymethyl, a n d aminoethyl groups modify chemically t h e surfaces of cotton fibers and p r o d u c e a varier}· of v a l u a b l e specific properties. Commercially finished cottons w i t h h a n d and drape properties simulating wool, a n d with increased flame resistance, h a v e b e e n introduced- T h e production of all-cotton felts, by a combination of chemical a n d mechanical ' t a n g l i n g , h a s been described in a series of p a t e n t s . A n e w mercerizing process h a s b e e n described in w h i c h cotton is p r e t r e a t e d w i t h a chlorinated solvent, t h u s affording faster treatment a n d lower costs. T h e effect of agricultural factors o n the fundamental physical a n d chemical behavior of cotton h a s been t h e subject of much rescent study, a n d other fundamental p r o g r a m s aimed a t strengthening t h e position of cotton as against t h e newer fibers a r e also b e i n g sponsoredIn t h e viscose r a y o n field t h e importance of crimp continues to b e recognized a n d several n e w p a t e n t s h a v e b e e n issued. F i b e r E , a viscose fiber particularly susceptible to c r i m p i n g processes, is recomm e n d e d for u s e i n plush fabrics, terry AND
ENGINEERING
NEWS
DEVELOPMENTS I N THE C H E M I C A L A N D PROCESS INDUSTRIES eio-'tbu knits, a n d carpets, where the high co>ver it affords is advantageous. Foreign aetr^Ety in the rayon field has increased greatK. with japane>e production nearing its prewar peak. Italian producers have offered new· combed y arns of exceptional fineness in counts up to 100*s. and a new Sat filament >arn called Viscol. V:>o>>e staple with a roughened "s-.ale> ** suniace has also been introduced- It is >^:d t*> be niadr· b> the use ou a vibrating ek-nrc-nî ixt the spinning apparatus. Extert>:vr >tud:e> on the delustering ci: acetate- ra>o>n are expected to lead to further adv. itères tiL tSi> field. Woo! The growing scarcity ot wool, which e-arher in the year led to record high prices and IUter to rapid fluctuation* in t h e market, has stimulated both basic a n d applied research on this fiber. Λ major in terest is in blends, with the object of .U'nubining the advantages of wool with those of the blending fiber. There is. how ever, an a-rrt to usty increased interest in >:r:d>Lng and improving the properties of ali-^oo-l rnaterials. Several new processes for overcoming felting vhrinkaue have been described in patents, among these b e ing treatment wtth resins, dry bleaching pOrt&JUrr. ehlorosulfamic; acid, and superhe-ated permanganate solutions. T h e feltabilrty and shrinkage properties of woolnylUa biends have been studied. Λ newly introdu-eed ~dry-in~ bleaching process, tnsing hydrogen peroxide, is said to afford raore ec^onorctical processing and a higher qtinahty end product. lodinated wool has been introduced for medicated dressings a n d is also said to be moth resistant. A British patent claims to improve t h e wash i-issn-ess oi dyed wool by treatment with epkMo)ro)hydrxn. Processes for reclaiming amd reworking wool have assumed increas ing nroupo>rtanee with the rising cost of new
A worker at the Carndert- S. C . plant of Dis Font inspects Orion acrylic fibers
fiber. A stripping process which con serves the original fiber properties has be come well established since its introduc tion two years ago. "ecently two new stripping processes have oeen announced, one of which features continuous operation in a conventional scouring train, while the other uses selected dyestuffs to effect stripping and redyeing in one bath. Processing, Dyeing, a n d Finishing Processing and finishing development has probably received a greater impetus from the arrival of t h e new fibers than any other branch of textile science. The dye ing of acrylic fibers a n d Dacron has pre sented challenging difficulties. Dispersion or solution of appropriate coloring mat ters in the melt before spinning has been suggested, but this seriously limits the range of possible color effects. An im portant advance has been made in the dis covery that a pretreatment with cuprous ions will facilitate the dyeing of both these fibers with acid, direct or even vat colors. High temperature dyeing techniques and t h e inclusion of chemical swelling agents are also effective, as in the case of nylon dyeing. Special ranges of acid and acetate colors have heen selected and recom m e n d e d by the major dyestuff suppliers for use on these fibers or their blends. Assistants such as benzoic and salicylic acid are said to promote t h e stripping of Dacron. Rapid continuous dyeing processes, ap plicable to a variety of fibers, continue to b e emphasized. Following the introduc tion of the Standfast process, which uses a bath of molten metal to fix the dyestuff, a new process utilizing hot oil is being offered and recommended for fixing pig ment padded vat and sulfur colors. A new series of dyestuffs a n d a process for color ing glass fibers without sacrificing flame resistance or draping qualities marks an other step forward in the technology of this material. The recent popular vogue for fluorescent clothing fabrics and the general adoption of fluorescent whites ( "optical bleaches") in household deter gents has stimulated increased activity in this field. Colors which will glow in the dark, applicable to cotton, rayon, and n> Ion, are being introduced in t h e clothing field together with a n array of n e w optical bleaches for finishing and scouring baths. Kmphasis in the latter field appears to be toward more uniform and spectrally pure whites. Information has been released that dyes and finishes have been devel oped which are not responsive to infra red detecting devices. Several new crease resistant and shrink resistant processes for cellulosic fabrics have been announced, both as commercial items and in patents. Many involve new developments in t h e application of low molecular weight aldehyde or ketone con densates. Treatments of cotton with vinyl sulfone and with strongly alkaline stannate solutions to impart dimensional sta bility have been claimed. A newly de-
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scribed system for minimizing the shrink age of cotton and cotton blend knits de pends on close control of temperature and humidity throughout the processing. Fire resistant finishes continue to occ jpy the attention of various research and de velopment groups, with several recent patents specifying phosphate-cyanamide combinations as well as the metallic oxides and chlorinated thermoplastics. A new thiourea-formaldehyde fire retardant finish for nylon is said to have high wash fast ness and very' little effect on handle or strength. A specially treated and modi fied Orion material has been exhibited which has fire resistant properties similar to those of t h e inorganic fibers. Soil re sistant finishes and the mechanisms whereby fabrics become soiled have been t h e subjects of several publications. Prod ucts such as carboxymethyl cellulose have been included in sizes and finishes to diminish soil pick-up and facilitate' soil removal. Studies of detergency effects on nylon and some of the newer fibers have also been reported. Considerable effort has been devoted to the study of heating and drying techniques in textile processing. Dielectric or induction heating systems as well as infrared units have been intro d u c e d . The latter are claimed to be par ticularly effective in curing resin finishes and setting fibers such as nylon. T h e ab sence of visible and ultraviolet rays is said to diminish yellowing and color altera tion. In t h e field of surface finishes polyamide suspensions are being promoted to in crease the warmth, softness and absorbency of the newer synthetic fibers. The static generating properties of these latter materials is arousing new interest in anti static finishes. Fatty derivatives of the strong nitrogen bases, and the polyethyl ene glycols, as well as alkyl phenols, have proved useful in fabrication, but the prob lem of a practical wash resistant finish of this type still awaits successful solution.
At a recent major textile meeting one of t h e speakers decried the flood of "nostrums, balms, elixirs and soothing sirups," offered in the past to a textile industry which was not fully clear as to its research needs. The impact of chem istry on textiles has brought many dra matic results, but possibly the most im portant is an appreciation of the dynamic research philosophy which has made this t h e chemical era. It is recognized that each major development, along with its advantages, brings new problems. The hydrophobicity of many of the new fibers, for example, facilitates the design of crease resistant and quick drying fabrics, but it creates problems of dyeing, static gener ation, and handle. The answers to such will probably be sought in chemical modi fications of t h e base fibers, old and new, and in new finishing treatments. Such a prospect promises an exciting continua tion of new developments for the future. 17
