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:
Jan. 27, 1981
Filed:
Feb. 26, 1979
Applicant:
Inventor:
Patrick H Fitzgerald, Edison, NJ (US);
Assignee:
E. I. Du Pont de Nemours and Company, Wilmington, DE (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C09B / ;
U.S. Cl.
CPC ...
546 49 ; 546 56 ; 546 57 ; 1062 / ;
Abstract
A process for preparing beta or gamma crystals of linear quinacridone, substituted quinacridone or solid solutions thereof by contacting premilled quinacridone with 45-60% by weight sulfuric acid and 0-10% by weight of a surfactant based on the quinacridone at a weight ratio of acid to quinacridone of 3:1-6:1 to form a slurry, agitating said slurry for a period of time at 45.degree.-75.degree. C., adding water to form a dilute slurry, agitating said dilute slurry for a period of time at 75.degree.-95.degree. C. and separating quinacridone from the liquid of the dilute slurry.