| abstract |
(57) Abstract: Aliphatic hydroxycarboxylic acids, polymers of aliphatic hydroxycarboxylic acids, aliphatic polycarboxylic acids and aliphatic polyhydric alcohols, and aliphatic polycarboxylic acids and aliphatic polyhydric alcohols Heating and refluxing at least one selected from the group consisting of polymers in an organic solvent in the presence of a catalyst, treating the organic solvent containing the distilled water produced with a desiccant and returning it to the reaction system again; A method for producing an aliphatic polyester by dehydration polycondensation by using an ion-exchange resin as a desiccant, regenerating and drying it after completion of the reaction, and repeatedly using it for the next reaction. . According to the present invention, a high-quality, high-molecular-weight aliphatic polyester having excellent color tone can be industrially, stably and efficiently produced. |