Fast crystallizing polyester compositions

摘要

Fast crystallizing polyester compositions obtained by reacting a polyester which is a block copolyester containing the repeating polymeric segments A and B wherein A is a polymeric segment of ethylene terephthalate units and B is a polymeric segment having a glass-transition temperature of less than 0 DEG C. and preferably less than -20 DEG C., the concentration of the segments of B being between 0.05 and 10 mole % preferably 0.1 to 5 mole % of the block copolyester, and an ionizable metal salt of an organic compound having at least one acidic proton using a concentration of ionizable metal salt which will convert at least 4% of the end groups of the polyester into carboxylate end groups but is insufficient to result in the melt degradation performance of the composition being substantially inferior to that of the polyester in the absence of the salt.