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:
Oct. 08, 1991
Filed:
Jun. 14, 1989
Applicant:
Inventors:
Assignee:
Bayer Aktiengesellschaft, Leverkusen, DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C09C / ;
U.S. Cl.
CPC ...
106456 ; 106499 ;
Abstract
A heat-stable iron oxide black pigment resistant to hydrothermal treatment in air at temperatures above 180.degree. C. and which has a specific BET surface of 0.5 to 5 m.sup.2 /g is useful as a coloring agent for building materials, paints, cements, bricks and so forth and is prepared by reacting an aqueous solution of FeOOH, iron (II) salts and alkalis at elevated temperature and precipitating iron oxide from the solution with Na.sub.2 CO.sub.3 at temperatures in the range from 80.degree. C. to the boiling point of the solution.