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:
Sep. 11, 2001
Filed:
May. 05, 1999
Akihiro Shishikura, Chiba, JP;
Seiji Takahashi, late of Saitama, JP;
Idemitsu Petrochemical Co., Ltd., Tokyo, JP;
Abstract
Processes for producing polycarbonate by solid phase polymerization which simplify the crytallization to be conducted prior to the solid phase polymerization to thereby permit further shortening in the treatment time. A process for producing polycarbonate is characterized in that an amorphous polycarbonate prepolymer prepared by transesterification of aromatic dihydroxy compound with a diester of carbonic acid is prepolymerized in a solid phase under an atmosphere containing gaseous swollen solvent while the prepolymer is kept in a fluid state. Another process for producing polycarbonate is characterized in that a mixture comprising an amorphous polycarbonate prepolymer prepared by transesterification of an aromatic dihydroxy compound with a diester of carbonic acid and a polycarbonate prepolymer which has undergone crystallization is prepolymerized in a solid phase under an atmosphere containing a gaseous swollen solvent.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile