Spandex elastomers

摘要

Spandex-type segmented polyurethane/urea elastomers having exceptional elongation, hysteresis, recovery, and other physical properties are prepared by the amine chain extension of an isocyanate-terminated prepolymer prepared by the reaction of a stoichiometric excess of isocyanate with a polyol blend comprising a low molecular weight diol having a molecular weight below 750 Da with a high molecular weight glycol which may be a 1500 Da to 20,000 Da molecular weight, ultra-low unsaturation polyoxypropylene glycol with an unsaturation of less than about 0.010 meq/g.