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:
Dec. 01, 1992
Filed:
Mar. 23, 1992
Applicant:
Inventors:
Volker Wilhelm, Bergisch Gladbach, DE;
Dieter Messer, Odenthal, DE;
Assignee:
Bayer Aktiengesellschaft, Leverkusen, DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C09C / ;
U.S. Cl.
CPC ...
106453 ; 106441 ;
Abstract
A process for the preparation of chromate-free, Cr.sub.2 O.sub.3 -containing pigments having a spinel, haematite or corundum structure comprises blending pigment-forming raw materials corresponding to the Cr.sub.2 O.sub.3 -containing pigments with from 0.5 to 10% by weight of boric acid or phosphoric acid, calculated as B.sub.2 O.sub.3 or P.sub.2 O.sub.5, respectively, and then annealing the blend whereby the chromate-free, Cr.sub.2 O.sub.3 -containing pigment is obtained.