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. 22, 1977
Filed:
Dec. 04, 1975
Applicant:
Inventors:
Jean-Pierre L Cartier, Evry, FR;
Jean-Pierre G Senet, Vaux le Penil, FR;
Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C07C / ;
U.S. Cl.
CPC ...
260463 ; 260 / ;
Abstract
The free and bonded residual phenol content of oligocarbonates prepared by transesterification between a diol and a diphenyl carbonate is substantially reduced by a process comprising (i) introducing water into the oligocarbonate in the liquid state at an elevated temperature under reduced pressure and (ii) purging the mixture with an inert gas to effect degassing. The purified oligocarbonates are particularly resistant to yellowing.