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. 14, 1999
Filed:
Apr. 02, 1998
Asahi Kasei Kogyo Kabushiki Kaisha, Osaka, JP;
Abstract
A method for producing an aromatic polycarbonate, which comprises subjecting to a transesterification polymerization reaction at least one polymerizable material for an aromatic polycarbonate. The transesterification polymerization reaction is performed in one or more polymerizers which is or are connected through a pipeline system. The pipeline system comprises one or more pipes through which a molten aromatic polycarbonate having a number average molecular weight increased by the transesterification polymerization reaction is passed while contacting an inner wall of the pipe or pipes. The pipeline system has at least one viscous polycarbonate passage region in which a molten aromatic polycarbonate having a number average molecular weight of 4,000 or more is passed through the pipe. The pipes in the viscous polycarbonate passage region of the pipeline system have no bent portion or not more than 50 bent portions in total. A high quality aromatic polycarbonate is produced, which is colorless and has a low foreign matter content.