Reinforced polyurethane tires

Claim 1

In a reinforced urethane tire formed by injecting a polyurea/polyurethane forming composition comprising a prepolymer having an excess of isocyanate groups and an aromatic diamine chain extender, into a tire mold, encapsulating a reinforcing cord in said tire and then curing said composition, the improvement for producing polyurea/polyurethane composition having low hysteresis which comprises reacting: (a) a prepolymer formed by the reaction of (1) an aromatic polyisocyanate represented by the formula: ##STR5## where R 1 R 2 R 3 R 4 represents H, alkyl from 1-4 carbon atoms, CN, halogen, CO 2 R 5 , CONR 6 R 7 where R 5 represents alkyl of 1-6 carbon atoms and R 6 R 7 represents alkyl of 1-6 carbon atoms and H, and mixtures thereof and (2) a polyol of about 500-5000 molecular weight of which at least 90% of the polyol is difunctional in a quantity sufficient to provide from about 2 to 12 weight % isocyanate groups in said prepolymer; with (b) a chain extender mix comprising (1) an aromatic diamine represented by the formula: ##STR6## where R 1 R 2 R 3 R 4 represents H, alkyl from 1-4 carbon atoms, CN, halogen, CO 2 R 5 , CONR 6 R 7 where R 5 represents alkyl of 1-6 carbon atoms and R 6 R 7 represents alkyl of 1-6 carbon atoms and H, and mixtures thereof and (2) a polyol having a molecular weight of from 500-5,000 of which at least 90% of polyol is difunctional, said diamine being present in said chain extender mix to provide a proportion of from 0.5-5 equivalents amine per equivalent polyol.