uranose-3,5-cyclic carbonate (IPXTC) which is an aliphatic cyclic carbonate, and a polylactic acid. According to this, it is described that the copolymer of 60 mol % of IPXTC as an aliphatic polycarbonate component, with a polylactic acid has Tg of 90° C. However, a compositional ratio of the copolymer of PLA and IPXTC, containing 60 mol % of IPXTC is converted into a weight ratio of PLA/IPXTC=18/82 (wt %), and an expensive IPXTC must be used in a large amount. Further, there are the problems that where the amount of IPXTC added is increased, the yield decreases, and the molecular weight of a copolymer obtained becomes low.
From the above facts, an aliphatic polymer having adequately high heat resistance and molecular weight and capable of producing economically is not known.    Patent Document 1: U.S. Pat. No. 6,093,792, pages 5-10    Non-Patent Document 1: Journal Fur Praktische Chemie Chemiker-Zeitung (1992), 334 (4), pages 298-310

Gray scale images of various documents are often stored on microfilm for subsequent retrieval in order to conserve storage space by advantageously eliminating the need to store bulky originals. Retrieving (accessing) a microfilmed image of a document, on a manual basis, typically requires locating a desired roll of microfilm that houses the desired image, loading the roll into a manual reader and then advancing the microfilm to a desired frame at which the image is located. Thereafter, the image is optically enlarged and displayed on the reader.
Now, to minimize image retrieval time, particularly for archives that store a substantial number of documents, and also to permit the retrieved image to be electronically enhanced and processed, image management systems have been developed in the art. These systems are typified, for example, by the Kodak Image Management System (KIMS) system currently manufactured by the present assignee (KIMS is a trademark of the Eastman Kodak Company). Essentially, the KIMS system first locates the desired microfilm roll and frame through a computerized