Wednesday, 30 March 2011 02:23

Synthetic Fibres

Written by
Rate this item
(1 Vote)

Adapted from 3rd edition, Encyclopaedia of Occupational Health and Safety.

Synthetic fibres are made from polymers that have been synthetically produced from chemical elements or compounds developed by the petrochemical industry. Unlike natural fibres (wool, cotton and silk), which date back to antiquity, synthetic fibres have a relatively short history dating back to the perfection of the viscose process in 1891 by Cross and Bevan, two British scientists. A few years later, rayon production started on a limited basis, and by the early 1900s, it was being produced commercially. Since then, a large variety of synthetic fibres has been developed, each designed with special characteristics that make it suitable for a particular kind of fabric, either alone or in combination with other fibres. Keeping track of them is made difficult by the fact that the same fibre may have different trade names in different countries.

The fibres are made by forcing liquid polymers through the holes of a spinneret to produce a continuous filament. The filament can be directly woven into cloth or, to give it the characteristics of natural fibres, it can, for example, be textured to add bulkiness, or it can be chopped into staple and spun.

Classes of Synthetic Fibres

The main classes of synthetic fibres used commercially include:

  • Polyamides (nylons). The names of the long-chain polymeric amides are distinguished by a number which indicates the number of carbon atoms in their chemical constituents, the diamine being considered first. Thus, the original nylon produced from hexamethylene diamine and adipic acid is known in the United States and the United Kingdom as nylon 66 or 6.6, since both the diamine and the dibasic acid contain 6 carbon atoms. In Germany, it is marketed as Perlon T, in Italy as Nailon, in Switzerland as Mylsuisse, in Spain as Anid and in the Argentine as Ducilo.
  • Polyesters. First introduced in 1941, polyesters are made by reacting ethylene glycol with terephthalic acid to form a plastic material made of long chains of molecules, which is pumped in molten form from spinnerets, allowing the filament to harden in cold air. A drawing or stretching process follows. Polyesters are known, for example, as Terylene in the UK, Dacron in the United States, Tergal in France, Terital and Wistel in Italy, Lavsan in the Russian Federation, and Tetoran in Japan.
  • Polyvinyls. Polyacrylonitrile or acrylic fibre, first produced in 1948, is the most important member of this group. It is known under a variety of trade names: Acrilan and Orlon in the United States, Crylor in France, Leacril and Velicren in Italy, Amanian in Poland, Courtelle in the UK and so on.
  • Polyolefins. The most common fibre in this group, known as Courlene in the UK, is made by a process similar to that for nylon. The molten polymer at 300 °C is forced through spinnerets and cooled in either air or water to form the filament. It is then drawn or stretched.
  • Polypropylenes. This polymer, known as Hostalen in Germany, Meraklon in Italy and Ulstron in the UK, is melt spun, stretched or drawn, and then annealed.
  • Polyurethanes. First produced in 1943 as Perlon D by the reaction of 1,4 butanediol with hexamethylene diisocyanate, the polyurethanes have become the basis of a new type of highly elastic fibre called spandex. These fibres are sometimes called snap-back or elastomeric on account of their rubber-like elasticity. They are manufactured from a linear polyurethane gum, which is cured by heating at very high temperatures and pressures to produce a “vulcanized” cross-linked polyurethane which is extruded as a monofil. The thread, which is widely used in garments requiring elasticity, can be covered by rayon or nylon to improve its appearance while the inner thread provides the “stretch”. Spandex yarns are known, for example, as Lycra, Vyrene and Glospan in the United States and Spandrell in the UK.

 

Special Processes

Stapling

Silk is the only natural fibre that comes in a continuous filament; other natural fibres come in short lengths or “staples”. Cotton has a staple of about 2.6 cm, wool of 6 to 10 cm and flax from 30 to 50 cm. The continuous synthetic filaments are sometimes passed through a cutting or stapling machine to produce short staples like the natural fibres. They can then be re-spun on cotton or wool spinning machines in order to produce a finish free of the glassy appearance of some synthetic fibres. During the spinning, combinations of synthetic and natural fibres or mixtures of synthetic fibres may be made.

Crimping

To give synthetic fibres the look and feel of wool, the twisted and tangled cut or stapled fibres are crimped by one of a number of methods. They may be passed through a crimping machine, in which hot, fluted rollers impart a permanent crimp. Crimping can also be done chemically, by controlling the coagulation of the filament so as to produce a fibre with an asymmetrical cross section (i.e., one side being thick-skinned and the other thin). When this fibre is wet, the thick side tends to curl, producing a crimp. To make crinkled yarn, known in the United States as non-torque yarn, the synthetic yarn is knitted into a fabric, set and then wound from the fabric by back-winding. The newest method passes two nylon threads through a heater, which raises their temperature to 180 °C and then passes them through a high-speed revolving spindle to impart the crimp. The spindles in the first machine ran at 60,000 revolutions per minute (rpm), but newer models have speeds of the order of 1.5 million rpm.

Synthetic Fibres for Work Clothes

The chemical resistance of polyester cloth makes the fabric particularly suitable for protective clothing for acid-handling operations. Polyolefin fabrics are suitable for protection against long exposures to both acids and alkalis. High-temperature-resistant nylon is well adapted for clothing to protect against fire and heat; it has good resistance at room temperature to solvents such as benzene, acetone, trichlorethylene and carbon tetrachloride. The resistance of certain propylene fabrics to a wide range of corrosive substances makes them suitable for work and laboratory clothing.

The light weight of these synthetic fabrics makes them preferable to the heavy rubberized or plastic-coated fabrics that would otherwise be required for comparable protection. They are also much more comfortable to wear in hot and humid atmospheres. In selecting protective clothing made from synthetic fibres, care should be taken to determine the generic name of the fibre and to verify such properties as shrinkage; sensitivity to light, dry-cleaning agents and detergents; resistance to oil, corrosive chemicals and common solvents; resistance to heat; and susceptibility to electrostatic charging.

Hazards and Their Prevention

Accidents

In addition to good housekeeping, which means keeping floors and passageways clean and dry to minimize slips and falls (vats must be leak proof and, where possible, have baffles to contain splashes), machines, drive belts, pulleys and shaftings must be properly guarded. Machines for spinning, carding, winding and warping operations should be fenced to keep materials and parts from flying out and to prevent workers’ hands from entering the dangerous zones. Lockout devices must be in place to prevent restart of machines while they are being cleaned or serviced.

Fire and explosion

The synthetic-fibres industry uses large amounts of toxic and flammable materials. Storage facilities for flammable substances should be out in the open or in a special fire-resistant structure, and they should be enclosed in bunds or dykes to localize spills. Automation of the delivery of toxic, flammable substances by a well-maintained system of pumps and pipes will reduce the hazard of moving and emptying containers. Appropriate fire-fighting equipment and clothing should be readily available and workers trained in their use through periodic drills, preferably conducted in concert with or under the observation of local fire-fighting authorities.

As the filaments emerge from the spinnerets to be dried in air or by means of spinning, large amounts of solvent vapours are released. These constitute a considerable toxic and explosion hazard and must be removed by LEV. Their concentration must be monitored to be sure that it remains below the solvent’s explosive limits. The exhausted vapours may be distilled and recovered for further use or they may be burned off; on no account should they be released into the general environmental atmosphere.

Where flammable solvents are used, smoking should be prohibited and open lights, flames and sparks eliminated. Electrical equipment should be of certified flameproof construction, and machines should be earthed (grounded) to prevent the build-up of static electricity, which might lead to catastrophic sparks.

Toxic hazards

Exposures to potentially toxic solvents and chemicals should be maintained below the relevant maximum allowable concentrations by adequate LEV. Respiratory protective equipment should be available for use by maintenance and repair crews and by workers charged with responding to emergencies caused by leaks, spillage and/or fire.

 

Back

Additional Info

Read 5288 times Last modified on Wednesday, 29 June 2011 08:17

" DISCLAIMER: The ILO does not take responsibility for content presented on this web portal that is presented in any language other than English, which is the language used for the initial production and peer-review of original content. Certain statistics have not been updated since the production of the 4th edition of the Encyclopaedia (1998)."

Contents

Preface
Part I. The Body
Part II. Health Care
Part III. Management & Policy
Part IV. Tools and Approaches
Part V. Psychosocial and Organizational Factors
Part VI. General Hazards
Part VII. The Environment
Part VIII. Accidents and Safety Management
Part IX. Chemicals
Part X. Industries Based on Biological Resources
Part XI. Industries Based on Natural Resources
Part XII. Chemical Industries
Part XIII. Manufacturing Industries
Part XIV. Textile and Apparel Industries
Clothing and Finished Textile Products
Leather, Fur and Footwear
Textile Goods Industry
Part XV. Transport Industries
Part XVI. Construction
Part XVII. Services and Trade
Part XVIII. Guides

Textile Goods Industry References

American Textile Reporter. 1969. (10 July).

Anthony, HM and GM Thomas. 1970. Tumors of the urinary bladder. J Natl Cancer Inst 45:879–95.

Arlidge, JT. 1892. The Hygiene, Diseases and Mortality of Occupations. London: Percival and Co.

Beck, GJ, CA Doyle, and EN Schachter. 1981. Smoking and lung function. Am Rev Resp Dis 123:149–155.

—. 1982. A longitudinal study of respiratory health in a rural community. Am Rev Resp Dis 125:375–381.

Beck, GJ, LR Maunder, and EN Schachter. 1984. Cotton dust and smoking effects on lung function in cotton textile workers. Am J Epidemiol 119:33–43.

Beck, GJ, EN Schachter, L Maunder, and A Bouhuys. 1981. The relation of lung function to subsequent employment and mortality in cotton textile workers. Chest suppl 79:26S–29S.

Bouhuys, A. 1974. Breathing. New York: Grune & Stratton.

Bouhuys, A, GJ Beck, and J Schoenberg. 1979. Epidemiology of environmental lung disease. Yale J Biol Med 52:191–210.

Bouhuys, A, CA Mitchell, RSF Schilling, and E Zuskin. 1973. A physiological study of byssinosis in colonial America. Trans New York Acad Sciences 35:537–546.

Bouhuys, A, JB Schoenberg, GJ Beck, and RSF Schilling. 1977. Epidemiology of chronic lung disease in a cotton mill community. Lung 154:167–186.

Britten, RH, JJ Bloomfield, and JC Goddard. 1933. Health of Workers in Textile Plants. Bulletin No. 207. Washington, DC: US Public Health Service.

Buiatti, E, A Barchielli, M Geddes, L Natasi, D Kriebel, M Franchini, and G Scarselli. 1984. Risk factors in male infertility. Arch Environ Health 39:266–270.

Doig, AT. 1949. Other lung diseases due to dust. Postgrad Med J 25:639–649.

Department of Labor (DOL). 1945. Special Bulletin No. 18. Washington, DC: DOL, Labor Standards Division.

Dubrow, R and DM Gute. 1988. Cause-specific mortality among male textile workers in Rhode Island. Am J Ind Med 13: 439–454.

Edwards, C, J Macartney, G Rooke, and F Ward. 1975. The pathology of the lung in byssinotics. Thorax 30:612–623.

Estlander, T. 1988. Allergic dermatoses and respiratory diseases from reactive dyes. Contact Dermat 18:290–297.

Eyeland, GM, GA Burkhart, TM Schnorr, FW Hornung, JM Fajen, and ST Lee. 1992. Effects of exposure to carbon disulphide on low density lipoprotein cholesterol concentration and diastolic blood pressure. Brit J Ind Med 49:287–293.

Fishwick, D, AM Fletcher, AC Pickering, R McNiven, and EB Faragher. 1996. Lung function in Lancashire cotton and man-made fibre spinning mill operatives. Occup Environ Med 53:46–50.

Forst, L and D Hryhorczuk. 1988. Occupational tarsal tunnel syndrome. Brit J Ind Med 45:277–278.

Fox, AJ, JBL Tombleson, A Watt, and AG Wilkie. 1973a. A survey of respiratory disease in cotton operatives: Part I. Symptoms and ventilation test results. Brit J Ind Med 30:42-47.

—. 1973b. A survey of respiratory disease in cotton operatives: Part II. Symptoms, dust estimation, and the effect of smoking habit. Brit J Ind Med 30:48-53.

Glindmeyer, HW, JJ Lefante, RN Jones, RJ Rando, HMA Kader, and H Weill. 1991. Exposure-related declines in the lung function of cotton textile workers. Am Rev Respir Dis 144:675–683.

Glindmeyer, HW, JJ Lefante, RN Jones, RJ Rando, and H Weill. 1994. Cotton dust and across-shift change in FEV1 Am J Respir Crit Care Med 149:584–590.

Goldberg, MS and G Theriault. 1994a. Retrospective cohort study of workers of a synthetic textiles plant in Quebec II. Am J Ind Med 25:909–922.

—. 1994b. Retrospective cohort study of workers of a synthetic textiles plant in Quebec I. Am J Ind Med 25:889–907.

Grund, N. 1995. Environmental considerations for textile printing products. Journal of the Society of Dyers and Colourists 111 (1/2):7–10.

Harris, TR, JA Merchant, KH Kilburn, and JD Hamilton. 1972. Byssinosis and respiratory diseases in cotton mill workers. J Occup Med 14: 199–206.

Henderson, V and PE Enterline. 1973. An unusual mortality experience in cotton textile workers. J Occup Med 15: 717–719.

Hernberg, S, T Partanen, and CH Nordman. 1970. Coronary heart disease among workers exposed to carbon disulphide. Brit J Ind Med 27:313–325.

McKerrow, CB and RSF Schilling. 1961. A pilot enquiry into byssinosis in two cotton mills in the United States. JAMA 177:850–853.

McKerrow, CB, SA Roach, JC Gilson, and RSF Schilling. 1962. The size of cotton dust particles causing byssinosis: An environmental and physiological study. Brit J Ind Med 19:1–8.

Merchant, JA and C Ortmeyer. 1981. Mortality of employees of two cotton mills in North Carolina. Chest suppl 79: 6S–11S.

Merchant, JA, JC Lumsdun, KH Kilburn, WM O’Fallon, JR Ujda, VH Germino, and JD Hamilton. 1973. Dose-response studies in cotton textile workers. J Occup Med 15:222–230.

Ministry of International Trade and Industry (Japan). 1996. Asia-Pacific Textile and Clothing Industry Form, June 3-4, 1996. Tokyo: Ministry of International Trade and Industry.

Molyneux, MKB and JBL Tombleson. 1970. An epidemiological study of respiratory symptoms in Lancashire mills, 1963–1966. Brit J Ind Med 27:225–234.

Moran, TJ. 1983. Emphysema and other chronic lung disease in textile workers: An 18-year autopsy study. Arch Environ Health 38:267–276.

Murray, R, J Dingwall-Fordyce, and RE Lane. 1957. An outbreak of weaver’s cough associated with tamarind seed powder. Brit J Ind Med 14:105–110.

Mustafa, KY, W Bos, and AS Lakha. 1979. Byssinosis in Tanzanian textile workers. Lung 157:39–44.

Myles, SM and AH Roberts. 1985. Hand injuries in the textile industry. J Hand Surg 10:293–296.

Neal, PA, R Schneiter, and BH Caminita. 1942. Report on acute illness among rural mattress makers using low grade, stained cotton. JAMA 119:1074–1082.

Occupational Safety and Health Administration (OSHA). 1985. Final Rule for Occupational Exposure to Cotton Dust. Federal Register 50, 51120-51179 (13 Dec. 1985). 29 CFR 1910.1043. Washington, DC: OSHA.

Parikh, JR. 1992. Byssinosis in developing countries. Brit J Ind Med 49:217–219.
Rachootin, P and J Olsen. 1983. The risk of infertility and delayed conception associated with exposures in the Danish workplace. J Occup Med 25:394–402.

Ramazzini, B. 1964. Diseases of Workers [De morbis artificum, 1713], translated by WC Wright. New York: Hafner Publishing Co.

Redlich, CA, WS Beckett, J Sparer, KW Barwick, CA Riely, H Miller, SL Sigal, SL Shalat, and MR Cullen. 1988. Liver disease associated with occupational exposure to the solvent dimethylformamide. Ann Int Med 108:680–686.

Riihimaki, V, H Kivisto, K Peltonen, E Helpio, and A Aitio. 1992. Assessment of exposures to carbon disulfide in viscose production workers from urinary 2-thiothiazolidine-4-carboxylic acid determinations. Am J Ind Med 22:85–97.

Roach, SA and RSF Schilling. 1960. A clinical and environmental study of byssinosis in the Lancashire cotton industry. Brit J Ind Med 17:1–9.

Rooke, GB. 1981a. The pathology of byssinosis. Chest suppl 79:67S–71S.

—. 1981b. Compensation for byssinosis in Great Britain. Chest suppl 79:124S–127S.

Sadhro, S, P Duhra, and IS Foulds. 1989. Occupational dermatitis from Synocril Red 3b liquid (CI Basic Red 22). Contact Dermat 21:316–320.

Schachter, EN, MC Kapp, GJ Beck, LR Maunder, and TJ Witek. 1989. Smoking and cotton dust effects in cotton textile workers. Chest 95: 997–1003.

Schilling, RSF. 1956. Byssinosis in cotton and other textile workers. Lancet 1:261–267, 319–324.

—. 1981. Worldwide problems of byssinosis. Chest suppl 79:3S–5S.

Schilling, RSF and N Goodman. 1951. Cardiovascular disease in cotton workers. Brit J Ind Med 8:77–87.

Seidenari, S, BM Mauzini, and P Danese. 1991. Contact sensitization to textile dyes: Description of 100 subjects. Contact Dermat 24:253–258.

Siemiatycki, J, R Dewar, L Nadon, and M Gerin. 1994. Occupational risk factors for bladder cancer. Am J Epidemiol 140:1061–1080.

Silverman, DJ, LI Levin, RN Hoover, and P Hartge. 1989. Occupational risks of bladder cancer in the United States. I. White men. J Natl Cancer Inst 81:1472–1480.

Steenland, K, C Burnett, and AM Osorio. 1987. A case control study of bladder cancer using city directories as a source of occupational data. Am J Epidemiol 126:247–257.

Sweetnam, PM, SWS Taylor, and PC Elwood. 1986. Exposure to carbon disulphide and ischemic heart disease in a viscose rayon factory. Brit J Ind Med 44:220–227.

Thomas, RE. 1991. Report on a multidisciplinary conference on control and prevention of cumulative trauma disorders (CDT) or repetitive motion trauma (RMT) in the textile, apparel and fiber industries. Am Ind Hyg Assoc J 52:A562.

Uragoda, CG. 1977. An investigation into the health of kapok workers. Brit J Ind Med 34:181–185.
Vigliani, EC, L Parmeggiani, and C Sassi. 1954. Studio de un epidemio di bronchite asmatica fra gli operi di una tessiture di cotone. Med Lau 45:349–378.

Vobecky, J, G Devroede, and J Caro. 1984. Risk of large-bowel cancer in synthetic fiber manufacture. Cancer 54:2537–2542.

Vobecky, J, G Devroede, J La Caille, and A Waiter. 1979. An occupational group with a high risk of large bowel cancer. Gastroenterology 76:657.

Wood, CH and SA Roach. 1964. Dust in cardrooms: A continuing problem in the cotton spinning industry. Brit J Ind Med 21:180–186.

Zuskin, E, D Ivankovic, EN Schachter, and TJ Witek. 1991. A ten year follow-up study of cotton textile workers. Am Rev Respir Dis 143:301–305.