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:
Mar. 29, 1983
Filed:
Nov. 04, 1981
Applicant:
Inventors:
Kevin F Dick, Lake Jackson, TX (US);
George E Ham, Lake Jackson, TX (US);
James R Gross, Lake Jackson, TX (US);
Assignee:
The Dow Chemical Company, Midland, MI (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C08G / ;
U.S. Cl.
CPC ...
526 59 ; 526 60 ; 526 71 ; 528196 ; 528199 ;
Abstract
Polycarbonates are prepared in homogeneous solutions from dihydric phenols and phosgene wherein the stoichiometric end point for the addition of phosgene is accurately controlled by using 4-(p-nitrobenzyl) pyridine as a colorometric indicator for the end point in a series of samples of the reaction solution.