| abstract |
PROBLEM TO BE SOLVED: To provide a novel production method for obtaining a polyester copolymer having high molecular weight, impact resistance, flexibility, and biodegradability, and a method for imparting impact resistance to polyhydroxycarboxylic acid. Offer. SOLUTION: The weight average molecular weight is 5,000 to 40. 0000 of a polyhydroxycarboxylic acid (A) and a polyester (B) comprising a dicarboxylic acid having a weight average molecular weight of 5,000 to 200,000 and a diol are melted, and then a transesterification catalyst (C) is added. A method for producing a polyhydroxycarboxylic acid-based copolymer, wherein the transesterification reaction is performed under reduced pressure. And an impact-imparting agent for polyhydroxycarboxylic acid comprising a polyhydroxycarboxylic acid-based copolymer obtained by the production method, And a polyester composition containing the impact modifier and a polyhydroxycarboxylic acid. |