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:
Mar. 09, 1999
Filed:
Jul. 08, 1996
Hitomi Ohara, Kyoto, JP;
Seiji Sawa, Ohtsu, JP;
Yasuhiro Fujii, Kyoto, JP;
Masahiro Ito, Kyoto, JP;
Masaaki Oota, Mukou, JP;
Shimadzu Corporation, Kyoto, JP;
Abstract
A method for producing a polylactic acid includes the steps of (a) crystallizing polylactic acid pellets obtainable by direct polymerization of lactic acid or ring-opening polymerization of lactide; and (b) removing low-molecular components having a weight-average molecular weight of 1,000 or less in the resulting crystallized, solid polylactic acid pellets by gasifying the low-molecular components to obtain polylactic acids with substantially no low-molecular components. In this method, an apparatus for removing low-molecular components in polylactic acid pellets includes a crystallizing means for maintaining a temperature between equal to or higher than a glass transition temperature of polylactic acid pellets and equal to or lower than the melting point thereof, while fluidizing the polylactic acid pellets; and a reactor for allowing a heated inert gas and/or heated air to pass through the resulting crystallized, solid polylactic acid pellets obtained by the crystallizing means.