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:
Aug. 06, 1991
Filed:
Apr. 06, 1990
Applicant:
Inventors:
John W Weston, Lake Jackson, TX (US);
Jose L Aguilar, Richwood, TX (US);
Ronald R Smith, II, Lake Jackson, TX (US);
Assignee:
The Dow Chemical Company, Midland, MI (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C08G / ;
U.S. Cl.
CPC ...
528196 ; 525462 ; 528198 ; 528199 ;
Abstract
Polycarbonate prepolymers are produced by adding phosgene, one or more dihydric phenols, a halogenated organic solvent, and an aqueous caustic solution together with mixing in motionless mixers to form fine dispersions of partially phosgenated phenols, allowing for interfacial reactions to occur in residence time sections and repeating the steps after the addition of caustic to form high molecular weight prepolymers. These prepolymers are then polymerized with amines to form high molecular weight polycarbonates.