Spandex, manufacture

Gut Rubber and Extruded Latex. The manufacturing technology for cut and extmded mbber thread is much older and more widely known than that for spandex fibers. Because production faciUties can be installed with relatively modest capital investment, manufacture of mbber thread is fragmented and more widely distributed with a few major and many minor producers. On a worldwide basis, Fikattice of Italy is the largest mbber thread producer with modem extmded latex plants in Italy, Spain, Malaysia, and the United States. Second in production capacity is the Globe Manufacturing Co., Fall River, Massachusettes with production operations in the United States and the UK. These firms also produce spandex fibers. 

Spandex Fibers. Spandex fibers are suppHed for processing into fabrics in four basic forms as outlined in Table 3. Bare yams are suppHed by the manufacturer on tubes or beams and can be processed on conventional textile equipment with the aid of special feed and tension devices. In covered yams, the spandex fibers are covered with one or two layers of an inelastic filament or staple yam the hard yam provides strength and rigidity at full extension, which faciUtates knitting and weaving. 

Butanediol [110-63-4] (BDO) goes primarily into tetrahydrofuran [109-99-9] (THE) for production of polytetramethylene ether glycol (PTMEG), used ia the manufacture of polyurethane fibers, eg, Du Font s Spandex. THE is also used as a solvent for PVC and ia the production of pharmaceuticals (qv). Lesser amounts of BDO are employed ia the production of polybutylene terephthalate resias and y-butyrolactone. 

Polymeric isocyanates or PMDI ate cmde products that vary in exact composition. The main constituents are 40—60% 4,4 -MDI the remainder is the other isomers of MDI, trimeric species, and higher molecular weight oligomers. Important product variables are functionaHty and acidity. Rigid polyurethane foams are mainly manufactured from PMDI. The so-called pure MDI is a low melting soHd that is used for high performance polyurethane elastomers and spandex fibers. Liquid MDI products are used in RIM polyurethane elastomers. 

Uses. Approximately 70% of the U.S. production is used to make poly(tetramethylene ether glycol) [25190-06-1] (PTMEG), also known as poly-THE, which is used in the production of urethane elastomers, polyurethane fibers (ether-based spandex), and copolyester—ether elastomers. PTMEG is also the fastest growing use (see PoLYETPiERS, TETRAHYDROFURAn). The remaining production is used as a solvent for the manufacture of poly(vinyl chloride) cements and coating, precision magnetic tape, a reaction solvent in the production of pharmaceuticals, and other miscellaneous uses. 

Clothes have long been made of natural fibers such as cotton, wool, and silk. But beginning in the 20th century, textile manufactures have had other options. Nylon was the first synthetic (human-made) fiber, introduced in 1939. Others, such as polyester and spandex, followed. These... 

We all use spandex, that extremely stretchable fiber known as elastane in Europe or called Lycra if manufactured by DuPont It provides the "stretch" in panty hose and other undergarments, swimsuits, jeans, cycling shorts, tights, and many other articles of clothing. 

Spandex stretch fiber, based on polyurethanes, was developed by DuPont and appeared in 1962. From this time, polyurethanes would account for the greater part of demand for anilines. Aniline production alone had more than doubled, to over 100 million lbs. per year, between 1939 and 1957, in part to satisfy demand in products other than dyes. Half the US output was consumed in the production of rubber additives, mainly diphenylamine and cyclohexylamine, the latter used as a chain stopper in manufacture of polyurethanes (also as a boiler water additive and, in the US until banned in 1970, in the manufacture of cyclamate sweeteners). Other polymers, such as epoxy resins, relied on the bulk availability of various aromatic amines (Chapter 14). 

OTHER COMMENTS used as a chemical intermediate in the manufacture of agricultural chemicals, spandex fibers and antioxidants used as a reducing agent in elcetrodeless nickel plating and in plutonium extraction from reactor waste used as a rocket propellant. 

Butanediol is used entirely as a precursor for other intermediates, polymers, and solvents. Its principal derivatives are tetrahydrofuran, butyrolac-tone, and pyrrolidones. Tetrahydrofuran can be polymerized to polytetra-methylene ether glycol (PTMEG), a key component in manufacturing spandex fibers. Another derivative, 7-butyrolactone, is a solvent used primarily for spinning polyester fibers. Pyrrolidones such as normal methyl pyrrolidone (NMP) are used as extraction solvents for producing lubricating oils. Other pyrrolidone derivatives are used as binders for pharmaceuticals. 

Butanediol (1,4 BDO) is an intermediate used to produce several important petrochemical and polymer derivatives. One of the most visible and widely used polymers is spandex fiber (polyurethane fiber) however, many other high performance polymers and solvents are made from 1,4 BDO. A complete description of supply, demand, and uses for its derivatives is included in Chapter 6. The manufacture of 1,4 BDO by each of several alternative commercial routes are major users of hydrogen for hydrogenation. 

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