Patent ID: 8580914
Filing Date: 2013-11-12
Classification: B01J,C08G

Abstract:
1. A process for producing an aliphatic polyester, comprising: Step 1: performing ring-opening polymerization of a cyclic ester to produce a partial polymer in a molten state of the aliphatic polyester, Step 2: continuously introducing the partial polymer in the molten state into a twin-screw stirring device to continuously obtain a partial polymer in a solid powdery particle state, at a conversion of 50-95%, Step 3: subjecting the partial polymer in the solid powdery particle state to solid-phase polymerization in an atmosphere of inert gas to obtain a solid polymer, and Step 4: melt-kneading the solid polymer after solid-phase polymerization together with a thermal stabilizer to form pellets of the aliphatic polyester, wherein the twin-screw stirring device is set at a temperature below a melting point of the partial polymer in the molten state, and contains an inert gas atmosphere.