Aliphatic polycarbonates contg. hydroxyl end gps. - prepd. by alcoholysis of dihydric alcohols with glycol carbonate without catalyst

摘要

Parent Patent describes prepn. of aliphatic polycarbonates contg. aliphatically bonded OH gps., by alcoholysis of dihydric alcohols with glycol carbonate. In the presently disclosed method alcoholysis takes place in absence of catalysts. Terminal OH gp.-contg. aliphatic polycarbonate obtd. is free from cpds. which might impair its subsequent reaction with polyisocyanates. An example is prepn. of colourless, waxy polycarbonate having OH-no. 65-67, by reacting 2 mol. hexanediol-1,6 and 2.2 mol. glycol carbonate in cumene, at 155 degrees C.