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:
May. 05, 2009
Filed:
Jun. 14, 2005
Shinsuke Fukuoka, Kurashiki, JP;
Hiroshi Hachiya, Kurashiki, JP;
Kazuhiko Matsuzaki, Yokohama, JP;
Asahi Kasei Chemicals Corporation, Tokyo, JP;
Abstract
It is a task of the present invention to provide a method which enables the production of a high quality, high performance aromatic polycarbonate (which is colorless and has excellent mechanical properties) from a molten aromatic polycarbonate prepolymer obtained from an aromatic dihydroxy compound and a diaryl carbonate, wherein the polycarbonate can be stably produced on a commercial scale at 1 to 50 t/hr for a long time without the need for a large amount of an inert gas. In the present invention, this task has been accomplished by a method for producing an aromatic polycarbonate by the melt transesterification process, in which the prepolymer is caused to absorb a specific amount of an inert gas, followed by polymerization using a guide-wetting fall polymerizer device having a specific structure, whereby a high quality, high performance aromatic polycarbonate as mentioned above can be stably produced on a commercial scale at 1 to 50 t/hr for a long time (more than several thousand hours, e.g., as long as 5,000 hours) without fluctuation of the molecular weight thereof.