| abstract |
(57) [Problem] To provide a method for easily producing an aliphatic polyester having a high molecular weight as a substitute for a general-purpose resin requiring toughness with high volumetric efficiency. SOLUTION: The weight average molecular weight is 2,000 to 100,0. The solid state polymerization temperature (reaction temperature) during the solid state polymerization of the crystallized aliphatic polyester prepolymer containing 50% or more of the aliphatic hydroxycarboxylic acid unit having a molecular weight of 00 in the presence of a catalyst. Of a weight average molecular weight of 50,000 to 1,000,000 A method for producing an aliphatic polyester containing at least 50% of an aliphatic hydroxycarboxylic acid unit. |