| abstract |
(57) Abstract: A method for efficiently and stably producing a modified biodegradable polyester is provided. SOLUTION: In the polymerization of an aliphatic polyester, a modifying component is added at a later stage of the polymerization reaction or after the completion of the polymerization reaction while keeping the polymerization reaction system in a molten state. In the case of polymerizing a lactic acid-based polymer, any of ring-opening polymerization of lactide and direct dehydration condensation of lactic acid may be used. After 70% by weight or more of the polymerization raw material has reacted, the modifying component is added. Modification components include aliphatic polyesters, alcohols, carboxylic acids, esters, lactic acid, and water. Decomposition of the modifying component can be minimized, and biodegradable polyesters of two or more varieties can be efficiently produced. |