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:
Jul. 24, 2018
Filed:
Nov. 06, 2015
Idemitsu Kosan Co., Ltd., Tokyo, JP;
Noriyuki Kunishi, Ichihara, JP;
Kazuhiro Sekiguchi, Chiba, JP;
Yukiko Nagao, Tokyo, JP;
Masayuki Takahashi, Taipei, TW;
Kenji Sasaki, Ichihara, JP;
IDEMITSU KOSAN CO., LTD., Tokyo, JP;
Abstract
Provided is a method of producing a branched polycarbonate, including: a step (a) of subjecting an alkali aqueous solution of a dihydric phenol, phosgene, and a branching agent to a phosgenation reaction in the presence of an organic solvent to provide a reaction liquid; a step (b) of adding the alkali aqueous solution of the dihydric phenol and a polymerization catalyst to the reaction liquid obtained from the step (a) to provide a reaction liquid containing a polycarbonate oligomer; a step (c) of separating the reaction liquid containing the polycarbonate oligomer obtained in the step (b) into an organic solvent phase containing the polycarbonate oligomer and an aqueous phase; and a step (d) of causing the organic solvent phase containing the polycarbonate oligomer separated in the step (c) and the alkali aqueous solution of the dihydric phenol to react with each other to provide a reaction liquid containing the branched polycarbonate, in which a ratio (x/y) of an addition amount of the polymerization catalyst to be added in the step (b), which is represented by x mol/hr, to a chloroformate group amount of the polycarbonate oligomer in the reaction liquid obtained from the step (b), which is represented by y mol/hr, is 0.0035 or more.