Spandex production

In the early 1960s when spandex production started in earnest there were four manufacturers E.I. DuPont deNemours (Lycra spandex), Monsanto, Globe Manufacturing (Glospan Cleerspan spandex), and American Cyanamid. At that time DuPont controlled approximately 80% of the market. Since then, Monsanto and Cyanamid have ceased manufacturing and DuPont expanded international production, but eventually sold its fiber business to Invista. Additional competitors have appeared on both the national and international scene. In the USA Lycra spandex is the best known of the competitors. 

Polyurethanes. About 3% of the U.S. polyurethanes market in 1988 was derived from the condensation product of polyisocyanates with low molecular weight polyadipates having hydroxyl end groups (195). In 1986 this amounted to 29,000 t, or 4% of total adipic acid consumption. The percentage was similar in Western Europe. About 90% of these adipic acid containing polyurethanes are used in flexible or semirigid foams and elastomers, with the remainder used in adhesives, coatings, and spandex fibers. 

Prices of spandex fibers are highly dependent on thread size selling price generally increases as fiber tex decreases. Factors that contribute to the relatively high cost of spandex fibers include (/) the relatively high cost of raw materials, (2) the small size of the spandex market compared to that of hard fibers which limits scale and thus efficiency of production units, and (J) the technical problems associated with stretch fibers that limit productivity rates and conversion efficiencies. 

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. 

Formaldehyde. Worldwide, the largest amount of formaldehyde (qv) is consumed in the production of urea—formaldehyde resins, the primary end use of which is found in building products such as plywood and particle board (see Amino resins and plastics). The demand for these resins, and consequently methanol, is greatly influenced by housing demand. In the United States, the greatest market share for formaldehyde is again in the constmction industry. However, a fast-growing market for formaldehyde can be found in the production of acetylenic chemicals, which is driven by the demand for 1,4-butanediol and its subsequent downstream product, spandex fibers (see Fibers, elastomeric). 

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. 

Use of 1,3 cycloaHphatic diamines in polyamides may be similarly limited by internal amide dehydration of the conformationaHy labile cis isomers to form a tetrahydropyrimidine (38) rather than high molecular weight polyamide. 1,3-Cyclohexanediamine is, however, a component of Spandex polyureas Du Pont uses the hydrogenation product of y -phenylenediamine [108-45-2] (24) captively to produce Lycra (see Fibers, elastomeric). 

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. 

The first commercial production of Spandex fibers by du Pont... 

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