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:
Jun. 28, 1988
Filed:
Dec. 26, 1985
Applicant:
Inventors:
Assignee:
Bayer Aktiengesellschaft, Leverkusen, DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C09C / ;
U.S. Cl.
CPC ...
106304 ; 106309 ;
Abstract
A bright, color-pure iron oxide red pigment is produced by an improved process by precipitation of iron(II) salts in aqueous solution with an alkaline precipitating agent, oxidation at temperatures of from 20.degree. C. to 100.degree. C. and annealing of the resulting precipitation products under air to form iron oxide red pigments, wherein the improvement comprises before adding the alkaline precipitating agent, the iron(III) content of the aqueous solution is adjusted to 1 to 15 mol %, based on the total iron content of the iron salt solution.