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:
Jan. 26, 2016
Filed:
May. 14, 2013
Mitsubishi Gas Chemical Company, Inc., Tokyo, JP;
Yoshinori Isahaya, Ibaraki, JP;
Atsushi Hirashima, Chiba, JP;
Hidefumi Harada, Hyogo, JP;
Maki Ito, Ibaraki, JP;
Jun-ya Hayakawa, Chiba, JP;
Takehiko Isobe, Chiba, JP;
Taichi Tokutake, Tokyo, JP;
Yousuke Shinkai, Chiba, JP;
MITSUBISHI GAS CHEMICAL COMPANY, INC., Tokyo, JP;
Abstract
A high molecular weight polycarbonate resin is continuously produced by subjecting an aromatic polycarbonate prepolymer and an aliphatic diol compound to a linking and highly polymerizing reaction. Even an aliphatic diol compound having a comparatively low boiling point can be allowed to efficiently contribute to the linking and highly polymerizing reaction. An aromatic polycarbonate prepolymer is produced by a polycondensation reaction between an aromatic dihydroxy compound and a diester carbonate, adding an aliphatic diol compound having an aliphatic group bonding to a terminal hydroxyl group to obtain a prepolymer mixture, and subjecting the resulting prepolymer mixture to a linking and highly polymerizing reaction under reduced pressure. The aliphatic diol compound is added at a pressure exceeding 200 torr, and the prepolymer mixture is subjected to a linking and highly polymerizing reaction before the terminal hydroxyl group concentration of the aromatic polycarbonate prepolymer in the prepolymer mixture reaches 2000 ppm.