Biodegradable Laminated Sheet: No. 7,235,287; Yosuke Egawa, assignors to Mitsubishi Plastics, Inc., Tokyo, Japan.

Biodegradable Laminated Sheet: No. 7,235,287; Yosuke Egawa, assignors to Mitsubishi Plastics, Inc., Tokyo, Japan. Filed 9/29/04. Issued 7/3/07.

A biodegradable laminated sheet comprising at least two layers was patented. Each of the two layers has a resin composition containing 75 to 25 mass percent of a polylactic acid resin, and 25 to 75 mass percent of a polyester resin with a glass transition temperature not exceeding 0 degrees C. The melting point is higher than the glass transition temperature of the polylactic acid resin, and does not exceed the melting point of the polylactic acid resin, based on 100 mass percent of the total amount of the polylactic acid resin and the polyester resin. The content Da (%) of D-lactic acid of the polylactic acid resin contained in one of the two layers and the content Db (%) of D-lactic acid of the polylactic acid resin contained in the other of the two layers satisfy the following relations: Da [less than or equal to] 7 and Db-Da>3. The laminated sheet is subjected to crystallization treatment.