Polyester with high carboxyl end groups and methods for making

摘要

The present invention relates to a polyester or copolyester composition containing a substituted cyclic anhydride, having a carboxyl end group of greater or equal to 25 mmol/kg. The present invention also concerns a method of making such a polyester or copolyester by late injection of the substituted cyclic anhydride at the end of polycondensation, or alternatively adding the substituted cyclic anhydride to the preform injection molding machine, prior to stretch blow molding a container.