Poly(urethane-urea) microcellular elastomer compositions

摘要

Poly(urethane-urea) reaction injection molded compositions having improved processing and lower water absorption are prepared by reacting an isocyanate-terminated prepolymer prepared by reacting 4,4'-MDI or modified 4,4'-MDI and a polyoxypropylene glycol having a molecular weight of from 400 to 2500 with a polyether polyol and a hindered amine or glycol chain extender, in the presence of a urethane-reaction promoting catalyst, optionally including a hydroxyl terminated chain extender and internal mold release agent.