The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 01, 1997
Filed:
Oct. 31, 1995
Hiroshi Itoh, Kobe, JP;
Yoshinobu Yamamoto, Suita, JP;
Koji Fukuhara, Osaka, JP;
Masahiro Shiroshima, Osaka, JP;
Hiroya Kobayashi, Minoo, JP;
Nippon Shokubai Co., Ltd., Osaka, JP;
Abstract
A method for producing an aliphatic polyester having a biodegradability and a higher melting point than conventional aliphatic polyester by suppressing a volatile component generated by side reaction or decomposition reaction with industrially good efficiency and economically in a relatively short period of time, the method enabling a polymerization at vacuum which permits a use of general vacuum pump. The aliphatic polyester can be obtained, for example, by a ring-opening copolymerization of a cyclic acid anhydride with a cyclic ether in a presence of a zirconium compound. The aliphatic polyester also can be obtained by performing a polymerization of raw materials of the aliphatic polyester so as to have a degree of viscosity in the range of 10-10,000 poise when 0.1-30 hours elapsed after the reaction started at reaction temperature of the reaction system under conditions of reaction temperature in the range of 180.degree. C. to 280.degree. C. and reaction pressure in the range of 0.3 mmHg to 3.0 mmHg.