Patent ID: 8507633
Filing Date: 2013-08-13
Classification: A43B,C08G

Abstract:
1. A process for the preparation of thermoplastic polyurethane by reacting (a) the isocyanate diphenylmethane 4,4′-diisocyanate with (b) compounds reactive toward isocyanates and having a molecular weight (M w ) of from 500 to 10 000 g/mol and (c) chain extenders having a molecular weight of from 50 to 499 g/mol, optionally in the presence of (d) catalysts and/or (e) conventional additives, wherein the chain extender is a mixture consisting of a main chain extender 1,4-butanediol (c1) and a co-chain extender 1,3-propanediol (c2) and the thermoplastic polyurethane prepared has a rigid phase fraction of greater than 0.40, said rigid phase fraction being defined by the following formula: wherein: M m M m k: number of chain extenders wherein the proportion of n1 of the main chain extender (c1), based on the total amount of n of the chain extender (c) used, is from 0.80 to 0.999.