Abstract: This invention relates to a process for the production of polyurethane/urea moldings from a reaction injection molding process by processing the reaction mixture consisting of a diisocyanate and an isocyanate-reactive component via the one-shot process at an isocyanate index of about 80 to 130. The diisocyanate is an unmodified cycloaliphatic diisocyanate. The isocyanate-reactive component consists of 1) at least one polyol having functional groups which are hydroxyl groups, amine groups, or mixtures of hydroxyl groups and amine groups such that the equivalent ratio of hydroxyl groups to amine groups is from 0:1 to 1:1, and 2) at least one chain extender which is selected from diols, triols, primary aliphatic amines, secondary aliphatic amines, aminoalcohols and mixtures thereof. The equivalent ratio of hydroxyl groups to amine groups in the chain extender component is from 1:2 to 10:1.

Abstract: 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.