POLYURETHANE/UREAS USEFUL FOR THE PRODUCTION OF SPANDEX AND A PROCESS FOR THEIR PRODUCTION

摘要

Segmented polyurethane/ureas useful in the production of spandex are produced by chain extending an isocyanate-terminated prepolymer in the presence of a solvent. The isocyanate-terminated prepolymer is formed by reacting a stoichiometric excess of an isocyanate with an isocyanate-reactive component that includes more than 50 equivalent percent of a high molecular weight polyoxyalkylene diol having an unsaturation level no greater than about 0.015 meq/g and up to about 50 equivalent percent of a polytetramethylene ether glycol.