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:
Sep. 25, 1990
Filed:
Apr. 28, 1989
Applicant:
Inventors:
Assignee:
Idemitsu Petrochemical Co., Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C08G / ;
U.S. Cl.
CPC ...
528371 ; 526 65 ; 528198 ; 528370 ;
Abstract
A process for producing polycarbonate from a polycarbonate oligomer and a phenol compound, comprising introducing the oligomer, caustic alkali and the phenol compound in the first reaction zone where polymerization is carried out to produce polycarbonate having a viscosity average molecular weight of 3,000 to 15,000, and then introducing the reaction mixture containing the above polycarbonate into the second reaction zone where polymerization is carried out while controlling the alkali concentration to the range of 0.05 to 0.7N by regulating caustic alkali supplied.