Polyurethane Rubbers and Spandex Fibers

Use Preparation of polyurethane resin and spandex fibers bonding rubber to rayon and nylon. 

OTHER COMMENTS useful in bonding rubber to rayon and nylon used in two-component polyurethane coating systems used for aircraft, tank trucks, and truck trailers also used to produce polyurethane lacquer coatings applied to certain automobile body components other uses are in production of thermoplastic polyurethane resins and spandex fibers. 

Uses preparation of polyurethane resin and Spandex fibers bonding of rubber to rayon diisocyanate in the production of polyurethane lacquers, foam plastics, rubber, and glues A... 

Spandex fibers are elastomeric fibers that are >85 % segmented polyurethane formed through reaction of a diisocyanate with polyethers or polyesters and subsequent crossl inking of polyurethane units. The spandex fibers resemble rubber in both stretch and recovery properties, but are far superior to mbber in their resistance to sunlight, heat, abrasion, oxidation, oils, and chemicals. They find the widest use of any of the elastomeric fibers. 

One particular form of thermoplastic polyurethane elastomer is the elastic fiber known as Spandex. Several commercial materials of this type have been introduced, which include Lycra (Du Pont), Dorlastan (Bayer) Spanzelle (Courtaulds), and Vyrene (U.S. Rubber). Spandex fibers have higher modulus, tensile strength, and resistance to oxidation, and are able to produce finer deniers than natural rubber. They have enabled lighter-weight garments to be produced. Staple fiber blends of Spandex fiber with non-elastic fibers have also been introduced. 

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). 

Elastic fibers that are at least 85% by weight of polyurethanes have the generic name spandex. The fibers may be produced by wet-spinning (see Section 14.3). One commercial fiber appears to be a prepolymer based on MDI and poly(tetrahydrofuran) that has been chain-extended with a diamine. The fibers find use in foundation garments, surgical hose, and swimsuits. In these applications, they appear to have displaced natural rubber thread that was made by slitting extruded, vulcanized rubber sheets. 

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