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. 16, 1995
Filed:
Sep. 17, 1993
Applicant:
Inventors:
Michael L Becraft, Woodstock, MD (US);
David L Ramsey, Mt. Vernon, IN (US);
Assignee:
General Electric Company, Pittsfield, MA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C08G / ;
U.S. Cl.
CPC ...
528196 ; 528198 ; 528199 ;
Abstract
A method for producing polycarbonates by the interfacial reaction of phosgene bisphenol in a two phase reaction medium of an aqueous hydroxide and an organic solvent is disclosed. In the reaction, the amount of water in the reaction medium is controlled such that high ionic strength conditions resulting from high salt concentrations are reached at the end of phosgenation and the pH of the medium is controlled to a range between 8 and 10 whereby excess phosgene usage is less than about 15% of theoretical conditions.