Biodegradable copolyesters and their preparation

摘要

A copolyester resin composition which has good physical properties and processability, wherein (i) 0.1wt% to 30wt% of an "aromatic-aliphatic prepolymer" having number average molecular weight of from 300 to 30,000; (ii) ) 40wt% to 71wt% of one or more aliphatic or alicyclic dicarboxylic acids or anhydrides and (iii) 29wt% to 60wt% of one or more aliphatic or alicyclic glycols are reacted together. The copolyester resin has a number average molecular weight of from 30,000 to 70,000, a weight average molecular weight of from 100,000 to 600,000, melting point of from 55 DEG C to 120 DEG C, and melt index (190 DEG C, 2,160g) of from 0.1 to 30 g/10min. The product is a high molecular weight copolyester which has biodegradability and physical properties required for packaging film and rubbish bags.