Patent ID: 8658252
Filing Date: 2014-02-25
Classification: C08L,C09D,D06N,E04D,Y10T

Abstract:
1. A process for production of a sealing membrane having stability to UV exposure and formed of a support or reinforcement, the support or reinforcement being coated on at least one surface and impregnated throughout, with a bitumen base composition, the bitumen base composition being a thermoplastic bituminous coating and or impregnation composition that has a following weight proportion based on a total weight of the composition: 60 to 80% bitumen, 15 to 40% thermoplastic polyurethane, 0 to 5% aromatic oil, 0 to 40% filler, and 0 to 0.5% catalyst, the bituminous coating and or impregnation composition is softenable by reheating and recover its properties after subsequent cooling, wherein the sealing membrane is applied by heating by torch welding or hot air, wherein the sealing membrane is stable to UV exposure, wherein the thermoplastic polyurethane is obtained from a diisocyanate of a functionality substantially equal to 2, a polyol of functionality substantially equal to 2, and a chain elongation agent, wherein the polyurethane molecules are free of double carbon-carbon bonds, and wherein the polyols are free of ethylene linkages, said process comprising: synthesizing a prepolymer of the thermoplastic polyurethane, introducing said prepolymer into the bitumen heated to a temperature higher than a melting temperature of the bitumen, adding a chain elongating agent, the catalyst and other components if present, heating and agitating to achieve polymerization, and applying the hot bitumen base composition in a layer on the support by one or more operations of coating or impregnation.