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:
Dec. 01, 1998
Filed:
Sep. 10, 1996
Yasutoshi Kakizawa, Chiba, JP;
Dainippon Ink and Chemicals, Inc., Tokyo, JP;
Abstract
The present invention provides a process for the preparation of a lactic acid-based polyester having an excellent moldability, storage stability and biodegradability which has a less residual lactide left therein and is less susceptible to decomposition of lactic acid-based polyester and attachment of sublimed lactide to the molding apparatus, etc. at the devolatilization step and molding step after the polymerization reaction of lactic acid-based polyester. In the present invention, an organic chelating agent is added to a lactic acid-based polyester to deactivate the esterification catalyst used in the preparation of the lactic acid-based polyester, making it possible to inhibit the decomposition of lactic acid-based polyester at the devolatilizing process and molding process after polymerization reaction. Accordingly, a process for the preparation of a lactic acid-based polyester useful as a packaging material such as film and sheet having a high molecular weight, a high heat resistance, good mechanical properties and excellent moldability, storage stability and biodegradability can be provided.