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:
Nov. 20, 2001
Filed:
Nov. 01, 2000
Kyosuke Komiya, Kurashiki, JP;
Shinsuke Fukuoka, Kurashiki, JP;
Muneaki Aminaka, Okayama, JP;
Kazumi Hasegawa, Kurashiki, JP;
Asahi Kasei Kabushiki Kaisha, Tokyo, JP;
Abstract
Disclosed is a method for producing an aromatic polycarbonate, which comprises treating a molten aromatic polycarbonate prepolymer (obtained by reacting an aromatic dihydroxy compound with a diaryl carbonate) with an inert gas under a predetermined pressure to thereby cause the molten prepolymer to absorb the inert gas, and subjecting the resultant molten prepolymer having the inert gas absorbed therein to polymerization, under a pressure lower than the above-mentioned predetermined pressure employed for the inert gas absorption, to thereby polymerize the prepolymer to a predetermined degree of polymerization. By the method of the present invention, a high quality aromatic polycarbonate which is colorless and has excellent mechanical properties can be produced at high polymerization rate even without using a large amount of an inert gas. Further, even if the production of an aromatic polycarbonate is conducted in a continuous manner, the molecular weight of the produced aromatic polycarbonate can be maintained at a desired level, so that the high quality polycarbonate can be stably produced for a prolonged period of time. Therefore, the method of the present invention is commercially very advantageous.