| 摘要 |
The present invention provides a process for the preparation of a decomposable lactic copolymer polyester which exhibits a sufficiently high molecular weight, heat resistance and thermal stability and further exhibits a rigidity, flexibility and transparency depending on the purpose. The process for the preparation of a high molecular lactic copolymer polyester includes reacting a polyester terminated by hydroxyl group at both ends (B1) with a polyvalent isocyanate (E) having 2 or more functionalities to obtain a polyester (B4) having a weight-average molecular weight of from 10,000 to 300,000, and then allowing said polyester (B4) and lactide (A) to undergo ring opening copolymerization in the presence of a ring opening polymerization catalyst (D). A process is also provided which includes allowing a lactide (A) and a polyester terminated by hydroxyl group at both ends (B1) to undergo ring opening copolymerization in the presence of a ring opening polymerization catalyst (D) to prepare a polyester having a weight-average molecular weight of from 10,000 to 300,000, and then reacting said polyester with a polyvalent isocyanate having 3 or more functionalities.
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