High modulus, high impact polyurethane/polyurea RIM

摘要

This invention relates to a process for the production of polyurethane/urea moldings which exhibit both high flexural modulus and high impact strength. The process comprises reaction injection molding of a reaction mixture in the presence of a catalyst via the one-shot process. The isocyanate component of this invention is a prepolymer of methylenebis(cyclohexyl isocyanate) having an NCO content of 12-27%, an average isocyanate functionality of less than 2.3, a monomer content of greater than about 25% by weight, and containing urethane or urea groups. The isocyanate-reactive blend comprises a high molecular weight polyether polyol and a low molecular weight chain extender, wherein the isocyanate-reactive blend has an OH:NH equivalent ratio of from 1:1 to 15:1. This invention also relates to the polyurethane/urea molded article produced by the above process.