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:
Mar. 27, 1990
Filed:
May. 02, 1988
Wilfried Burow, Krefeld, DE;
Hans-Ulrich Hofs, Krefeld, DE;
Karl-Werner Ganter, Krefeld, DE;
Gerd-Hermann Schulten, Duisburg, DE;
Bayer Aktiengesellschaft, Leverkusen-Bayerwerk, DE;
Abstract
Iron oxide red pigments comprise clusters of a plurality of pigment particles, preferably at least five intergrown spherical particles, are prepared by conducting nuclear formation of iron oxide yellow .alpha.-FeOOH in the presence of compounds of the elements, B, Al, Ga, Si, Ge, Sn or mixtures thereof in quantities of from 0.05 to 10% by weight, calculated as tri- or tetravalent oxides and based on the arithmetically calculated precipitated .alpha.-FeOOH nuclei, separating brine from the resulting yellow slurry to isolate an iron oxide yellow paste, drying and annealing the paste to form iron oxide red pigment and grinding the red pigment, which pigment is useful in coloring foodstuffs, lacquers, plastics and building materials.