Abstract: Thermoplastic polyurethanes are treated in the solid particulate state with a volatile free agent selected from alcohols and amines which are reactive with NCO groups at a temperature below that at which aminolysis or alcoholysis of urethane groups takes place, continuing the treatment until the reagent is substantially diffused throughout the polyurethane, and then pulling a vacuum on the treated polyurethane to remove any unreacted reagent.

Abstract: Polyurethane resins of higher than desired molecular weight with or without gel fractions which comprise insoluble material due to crosslinking or excessive degree of polymerization are treated in the solid state with a liquid or gaseous primary or secondary amine under thermal conditions which cause aminolysis of both linear linkages and crosslinkages. By this procedure, the average molcular weights of the products can be reduced to acceptable levels. Also, if the product contains gel fractions, these too can be reduced to negligible levels. The procedure is applicable to both polyether and polyester urethanes and is effective to provide improved polymer characteristics for thermoplastic processing and solution applications.

Abstract: Polyurethane resins of higher than desired molecular weight with or without gel fractions which comprise insoluble material due to crosslinking or excessive degree of polymerization are treated with a liquid or gaseous primary or secondary amine under thermal conditions which cause aminolysis of both linear linkages and cross linkages. By this procedure, the average molecular weights of the products can be reduced to acceptable levels. Also, if the product contains gel fractions, these too can be reduced to negligible levels. The procedure is applicable to both polyether and polyester urethanes and is effective to provide improved polymer characteristics for solution applications.