Abstract
The chemistry and technology of urethane elastomers has advanced rapidly since their inception in Europe in the late 1930'a and early 1940's. The earliest elastomers were Vulkollan, developed by I. G. Farbenindustrie (IGF) and Vulcaprene, developed by Imperial Chemical Industries (ICI). IGF developed a casting process for Vulkollan, while the processing of Vulcaprene was carried out on conventional rubber equipment. While these elastomers were crosslinked, new types of urethane elastomers were developed which were thermoplastic in nature and allowed processing by means of conventional thermoplastic processing equipment. Urethane elastomers were also developed in various other forms such as latices, solutions in organic solvents, poromeric sheets, spandex fibers, sealants and caulks (consisting generally of low modulus elastomers), and expanded or micro-cellular elastomers. Omitting spandex fibers and poromerics, urethane elastomers can be classified according to the method of processing by which they are produced: