PROCESS FOR THE THERMOPLASTIC WORKING UP OF POLYURETHANES

摘要

A PROCESS FOR THE THERMOPLASTIC PROCESSING OF POLYURETHANES The present invention relates to a process for the thermoplastic processing of polyurethanes via the melt phase wherein said polyurethanes have a melt viscosity which is substantially independent of the molar ratio of isocyanate groups to active hydrogen containing groups. These polyurethanes comprise the reaction product of A) one or more polydiols having an average molecular weight of from 550 to 10,000, B) one or more chain extending agents having a molecular weight below 500, an average functionality of about 2, and containing amino and/or hydroxyl groups as functional groups, and C) one or more diisocyanates wherein said components are present in quantities such that the molar ratio of the isocyanate groups to the Zerewitinoff-active hydrogen containing groups is at least 1.10:1, and the polyurethanes are subjected to a temperature treatment prior to thermoplastic processing.