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. 14, 2000
Filed:
Dec. 09, 1997
Kyosuke Komiya, Kurashiki, JP;
Kazumi Hasegawa, Kurashiki, JP;
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 selected from a molten monomer mixture of an aromatic dihydroxy compound and a diaryl carbonate, and a molten prepolymer obtained from the monomer mixture, wherein the transesterification reaction is performed in one or more polymerizers which is or are connected through a pipeline system toward an outlet for a final aromatic polycarbonate product, wherein 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, and wherein a molten aromatic polycarbonate having a number average molecular weight of less than 2,500 is passed through the pipe or pipes at a velocity of 0.05 m/sec. or more and a molten aromatic polycarbonate having a number average molecular weight of 2,500 or more is passed through the pipe or pipes at a velocity of 0.005 m/sec. or more. By the method of the present invention, a high quality aromatic polycarbonate which is not only highly colorless but also has a low foreign matter content can be produced by using an ordinary pipeline system comprising the pipe or pipes made of an ordinary material.