| 摘要 |
The present invention is directed to polyurethane moldings produced via the RIM process. These polyurethane moldings have excellent reactivity, demold properties (at a 30s demold), and good elongation and tear strength, and comprise the reaction product of an aliphatic polyisocyanate having a viscosity of less than about 20,000 mPa.cndot.s at 25.degree.C and a NCO functionality of 2.3 to 4.0 with an isocyanate-reactive component comprising b1) a relatively high molecular weight organic compound containing at least one of the groups selected from the group consisting of hydroxy groups and amine groups; and b2) a low molecular weight chain extender selected from the group consisting of diols, triols, primary amines, secondary amines, aminoalcohols, and mixtures thereof; in the presence of a catalyst. The OH:NH ratio of the chain extender is from 1:1 to 25:1.
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