ALIPHATIC POLYESTER COPOLYMER AND PROCESS FOR PRODUCING THE SAME, BIODEGRADABLE RESIN MOLDING BASED ON ALIPHATIC POLYESTER, AND LACTONE-CONTAINING RESIN

摘要

A high molecular weight aliphatic polyester copolymer, a high molecular weight aliphatic polyester copolymer containing polylactic acid; process for industrially producing these copolymers; composition of these copolymers; and various uses thereof. These copolymers have practical properties which make the copolymers moldable. They are free from the problem of plasticizer bleeding and can be degraded by microorganisms present in soils or water. They give moldings, such as sheets and films, which combine a sufficient strength with tear resistance. When the copolymers are ones having a branched structure, they give a molding having excellent mechanical properties. The moldings obtained from compositions containing either of these copolymers are excellent in elongation and biodegradability and have a satisfactory balanc therebetween. In particular, blending with one or more other biodegradable resins gives a molding having better moldability.