Patent ID: 6964626

Claim:
A power transmission belt subject to dynamic loading in use formed from a solid polyurethane/urea elastomer composition having high temperature resistance to about 140° C. and low temperature resistance to about −35° C. in dynamic applications, comprising the reaction product of: (a) a polyisocyanate prepolymer composition being prepared by reacting, (i) a diisocyanate selected from the group consisting of, (A) para-phenylene diisocyanate, (B) 2,6-toluene diisocyanate, and (C) a cycloaliphatic diisocyanates with trans or trans, trans geometric structure, with; (ii) a polyol substantially free of moieties oxidative at less than about 150° C. and selected from the group consisting of; (A) polycarbonate polyols, (B) polyester polyols, and (C) mixtures of said polycarbonate polyols and said polyester polyols, and; (b) a chain extender which contributes increased thermal stability to the polyurethane/urea elastomer, selected from the group consisting of; (i) aromatic symmetric primary diamine chain extenders, (ii) mixtures of said aromatic symmetric primary diamine chain extenders and aromatic secondary diamine chain extenders, and; (iii) mixtures of said aromatic symmetric primary diamine chain extenders and said polyols; said polyurethane/urea elastomer composition having an isocyanate to amine or amine/hydroxyl equivalent ratio of from about 0.95:1 to about 1.20:1, and said polyisocyanate prepolymer composition having an isocyanate group content of from about 2% to about 12% by weight.