PROCESS FOR PREPARING THERMOPLASTIC POLYURETHANES BY A JOINT THERMOPLASTIC TREATMENT OF HYDROXYL-POLYURETHANE AND ISOCYANATE-POLYURETHANE

摘要

A process is disclosed for the production of thermoplastic polyurethanes by the combined thermoplastic treatment of a) a polyurethane and/or polyurethane polycarbamide with free hydroxyl groups and/or amino groups and b) a polyurethane and/or polyurethane polycarbamide obtainable by the isocyanate-polyaddition process with a characteristic number of above 100. The process is characterized by the fact that : i) in the production of component b) the characteristic number is between 110 and 150 and ii) in the thermoplastic treatment of components a) and b), the molar ratio of the theoretical isocyanate surplus of component b) to the free hydroxyl groups and/or amino groups content of component a) ranges from 1.02:1 (mol NCO:mol OH or NH2) to 100:1.