Viscose rayon industry

However, since reliable data on exposure levels were not available, it is impossible to establish a dose-response relationship or a NOAEL. In addition, coronary heart disease has a multicausal origin that is in part related to the saturated fat intake of the population and is also influenced by a large number of other risk factors such as smoking, other dietary habits, diabetes, and physical inactivity. A combination of two or more risk factors greatly increases the incidence of coronary heart disease, and therefore carbon disulfide may be a cofactor in the presence of other risk factors (WHO 1979). Another limitation with occupational studies reported from the viscose rayon industry is concurrent exposure to other chemicals such as hydrogen sulfide (Hemberg et al. 1970 Rubin and Arieff 1945 Swaen et al. 1994 Tolonen et al. 1979). 

Trends in carbon disulfide production have closely paralleled those of the viscose rayon industry, one of its largest users (HSDB 1995 Mannsville Chemical Products Corp. 1985 Timmerman 1978 WHO 1981). Production increased by nearly 50% between 1941 and 1969, from 242,000 to 362,000 metric tons. This increase was partly due to a sudden rise in demand for carbon tetrachloride, an intermediate in the production of fluorocarbon propellants and refrigerants carbon disulfide is used in the production of carbon tetrachloride. The 1969 production level remained relatively stable until about 1974 when it declined sharply to the 1975 level of 217,000 metric tons (Timmerman 1978). Carbon disulfide production levels continued to decline, with fluctuations, to 168,000 metric tons in 1984 (Mannsville Chemical Products Corp. 1985 Timmerman 1978). In 1985, production was estimated to be 143,000 metric tons (Mannsville Chemical Products Corp. 1985). No information was found on production levels after 1985. 

Production, Import/Export, Use, Release, and Disposal. Little specific information is available on the levels of carbon disulfide emitted from industrial sources. Most of the literature concentrates on the viscose rayon industry (EPA 1975b Battista and Connelly 1989 Carroll 1985 CIS 1989 Cooper et al. 1987 DeMello et al. 1987 EPA 1979, 1978a Fain et al. 1987 Rasmussen et al. 1982 Ruby et al. 1987 Sax and Lewis 1987 South Carolina DOH 1986 Spencer 1982 SRI 1989 Staubes et al. 1987 Timmerman 1978 TRI93 1995 View 1989 Vogt and Walsh 1985 WHO 1979, 1981 Windholz 1983 ... 

Cirla AM, Villa A, Tomasini M. 1972. [Investigation of the incidence of coronary disease in workers exposed to carbon disulfide in a viscose-rayon industry], Med Lav 63 431-441. (Italian, with English summary)... 

Freitag. 1931. Injury to health in the viscose rayon industry. Melliand Textile Monthly 3 758-759. 

Reece GM, White B, Drinker P. 1948. Determination and recording of carbon disulfide and hydrogen sulfide in the viscose-rayon industry. J Ind Hyg Toxicol 22 416-424. 

Seppalainen AM, Tolonen MT. 1974. Neurotoxicity of long-term exposure to carbon disulfide in the viscose rayon industry A neurophysiological study. Work Environ Health 11 145-153. 

This chapter deals merely with exposure to common organic solvents which are used in large quantities to dissolve fats, resins, and other materials. Very dangerous chemicals, such as benzene, which are no more used as solvents due to their toxic properties, will not be discussed even though they may have had even extensive uses as solvents earlier and even though those may be still important chemicals as petroleum components or as intermediates for other chemicals. Also, solvents with very specialized uses, such as carbon disulfide the use of which is practically limited to viscose rayon industry and laboratories, are only... 

Carbon disulfide was the first solvent studied and had adverse effects observed by Delpech in 1863. Neuropsychiatric abnormalities were described 13 years later by Eulenberg in workers in the rubber and viscose rayon industries. A Finnish psychologist, Helen Hanninen tested 100 carbon disulfide exposed workers in 1970,50 were poisoned, 50 exposed and compared them to 50 unexposed.She found intelligence, tasks of attention, motor skill vigilance and memory were impaired in clinically poisoned and exposed men compared to unexposed. Digit symbol substitution from the Wechsler s scale showed the most effect of exposure. Additional studies of spray painters in the 1970 s and compared to computer augmented tomography (CT) scans of the brain and function tests. Symptomatic painters after 20 years or more of exposure had brain atrophy associated with impairment."" ... 

Commencing in the late 1930s, new developments to make very strong yams allowed the viscose rayon to replace cotton as the fiber of choice for longer life pneumatic tires. The pace of this line of development increased during World War II, and by the 1960s a significant part of the production of viscose yam was for tires and industrial appHcations. 

CeUulose is the most abundant polymer, an estimated 10 t being produced aimuaUy by natural processes. SuppUes for the rayon industry can be obtained from many sources, but in practice, the wood-pulping processes used to supply the needs of the paper and board industries have been adapted to make the necessary speciaUy pure grade. Of the 3 x 10 t of wood used by the paper and board industry (13) in 1989, about 6 x 10 t were purified to provide the 2.5 x 10 t of dissolving pulp required by the viscose processes. 

Neste patented an industrial route to a cellulose carbamate pulp (90) which was stable enough to be shipped into rayon plants for dissolution as if it were xanthate. The carbamate solution could be spun into sulfuric acid or sodium carbonate solutions, to give fibers which when completely regenerated had similar properties to viscose rayon. When incompletely regenerated they were sufficientiy self-bonding for use in papermaking. The process was said to be cheaper than the viscose route and to have a lower environmental impact (91). It has not been commercialized, so no confirmation of its potential is yet available. 

World production in 1991 was about 1 million tonnes the principal industrial uses being in the manufacture of viscose rayon (35-50%), cellophane films (15%) (see below), and CCI4 (15 30%) depending on country. Indeed the CCI4 application dropped to zero in USA in 1991 because of environmental concerns (p. 304). 

Other uses of HCI are legion and range from the purification of fine silica for the ceramics industry, and the refining of oils, fats and waxes, to the manufacture of chloroprene mbbers, PVC plastics, industrial solvents and organic intermediates, the production of viscose rayon yam and staple fibre, and the wet processing of textiles (where hydrochloric acid is used as a sour to neutralize residual alkali and remove metallic and other impurities). 

There are ten viscose rayon manufacturing plants in the U.S., all of which are believed to use zinc sulfate in their spinning bath. This process greatly enhances the economics of removing this source of zinc pollution, allowing neutralization of the acid stream and recovery of the zinc while generating a good profit for industrial yarns and at a moderate cost for textile yams. 

Since bacterial cellulose from all suitable carbohydrate substrates i8 identical with natural cellulose, its industrial importance20 is obvious. Relatively large amounts of bacterial cellulose were produced in Germany during the first World War. More recently products similar to parchment, mercerized cotton, cellulose nitrate,21 acetate14 and viscose rayons have been produced from bacterial cellulose. 

In the original process the cellulose nitrate itself was used as the fiber (hence its satirical description as mother-in-law silk ). The regenerating agent is ammonium hydrosulfide. The basic process was first demonstrated by J. W. Swan in London in 1885 but commercialized by Count L. M. H. B. de Chardonnet ( Father of the rayon industry ) in France in 1891 and operated there until 1934. The last working factory, that in Brazil, was burnt down in 1949. The other processes for making rayon fibers by regenerating cellulose ( viscose, cupram-monium) gave superior products. See also Rayon. 

Rigid PVC is one of the polymers which are sometimes colored by P.R.112. Transparent systems (0.1% pigment) equal step 8 on the Blue Scale for lightfastness while the lightfastness of white reductions is only step 5-6. The spin dyeing industry employs P.R.142 for viscose rayon and viscose cellulose, in which the pigment exhibits excellent lightfastness and performs, if not perfectly, then almost satisfactorily. 

P.R.170 is not always heat stable enough to allow application in polyolefins. In HDPE systems formulated at 1/3 SD, the pigment tolerates exposure to 220 to 240°C for one minute. Its tinctorial strength, on the other hand, is excellent. P.R.170 is also occasionally used in polypropylene and polyacrylonitrile spin dyeing in the latter medium, it satisfies the specifications of the clothing and home textiles industries. Besides, P.R.170 lends color to viscose rayon and viscose cellulose it is used for the mass coloration of semisynthetic fibers made of cellulose last but not least, it colors yarns, fibers, and films made of secondary acetate. 

In a few cases other redox systems are recommended to initiate grafting to cellulose. Asahi Chemical Industries (62) was granted a patent to graft acrylonitrile to viscose rayon fibers using ferrous sulphate and sodium formaldehyde-sulphoxylate as initiator. 

Also other oxidants have been used successfully to initiate graft copolymerization onto cellulose substrates. Toyo Rayon (79) achieved grafting by pretreatment of viscose rayon fibers with potassium permanganate-sulfuric acid and contacting it subsequently with acrylonitrile. Methyl methacrylate is being grafted to rayon when heated together with potassium bromate, as claimed by Asahi Chemical Industry... 

The production of aldehyde groups through periodate oxidation and subsequent formation of oxime groups is being used as a basis for an anionic initiation of grafting with titanium chloride as catalyst according to a process claimed by Asahi Chemical Industries Company (135). With this method styrene was grafted onto viscose rayon. Also bi- and tri-valent vanadium salts can be used as initiators. 

The natural fibers obtained from cotton, wood, flax, hemp, and jute all are cellulose fibers and serve as raw materials for the textile and paper industries. In addition to its use as a natural fiber and in those industries that depend on wood as a construction material, cellulose is used to make cellulose acetate (for making rayon acetate yarn, photographic film, and cellulose acetate butyrate plastics), nitric acid esters (gun cotton and celluloid7), and cellulose xanthate (for making viscose rayon fibers). The process by which viscose rayon is manufactured involves converting wood pulp or cotton Iinters into cellulose xanthate by reaction with carbon disulfide and sodium hydroxide ... 

Substances that can be metabolized to y-diketones, such as -hexane, which is metabolized to 2,5-hexanedione, cause the same disorders. Examples of the many other substances known to cause axonopathies are colchicine, disulhram, hydralazine, misonidazole, and insecticidal pyrethroids. Peripheral neuropathy is the most common kind of axonopathic disorder. However, other symptoms may be observed. Numerous cases of manic psychoses were produced in workers exposed to carbon disulfide, CS2, in the viscose rayon and vulcan rubber industries. 

Use and exposure Pure carbon disulfide is a colorless liquid with a sweet odor similar to that of chloroform, while impure carbon disulfide is a yellowish liquid with an unpleasant odor like that of rotting radishes. Exposure to carbon disulhde occurs in industrial workplaces. Industries associated with coal gasihcation plants release carbon disulfide, carbonyl sulfide, and hydrogen sulhde. Carbon disulhde is used in large quantities as an industrial chemical for the production of viscose rayon hbers. In fact, the major... 

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