Patent ID: 8779084

Claim:
A process for producing a polyether-polyester block copolymer, comprising: (a) carrying out a transesterification reaction of at least one di(C 1 -C 4 )alkyl ester of an aromatic dicarboxylic acid and at least one aliphatic diol or aliphatic polyol in an inert solvent to obtain a product of step (a) and an alcohol by-product, wherein the inert solvent, having a boiling point higher than the boiling point of the alcohol by-product, is one or more selected from the group consisting of diethylene glycol di(C 1 -C 4 )alkyl ethers, and dipropylene glycol di(C 1 -C 4 )alkyl ethers; and (b) carrying out a polycondensation reaction of the product of step (a) and at least one polyether to obtain the polyether-polyester block copolymer, wherein the polyether has at least one terminal hydroxyl group.