POLIURETANO E PROCESSO PARA SUA PREPARACAO

摘要

This invention is directed to polyurethanes and to a process for preparing polyurethanes having a flexural modulus ratio (-29 DEG C/70 DEG C) not greater than 3.4 and having at least three thermal transition temperatures between -100 DEG C and the decomposition temperature of the polyurethane as determined by thermomechanical analysis. The polyurethane is prepared by admixing and reacting three active hydrogen compounds with a polyisocyanate or polyisothiocyanate wherein one of the active hydrogen compounds has a reactivity with a polyisocyanate greater than the reactivity of either of the other two active hydrogen compounds. The polyurethanes of this invention are suitable for metal replacement applications wherein the polyurethane is formed by reaction injection molding.