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:
Feb. 15, 1994
Filed:
Dec. 18, 1991
Applicant:
Inventors:
Fridolin Babler, Hockessin, DE (US);
Edward E Jaffe, Wilmington, DE (US);
Assignee:
Ciba-Geigy Corporation, Ardsley, NY (US);
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
C09B / ;
U.S. Cl.
CPC ...
546 56 ; 546 49 ; 106497 ;
Abstract
A process for preparing quinacridone pigments comprising oxidizing 6,13-dihydroquinacridone or derivatives thereof at elevated temperatures in the presence of a base, dimethyl sulfoxide medium and a quinone catalyst, drowning the resulting pigment solution to precipitate the quinacridone pigment and isolating the desired quinacridone product.