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. 10, 1978
Filed:
Feb. 06, 1976
Manfred Mansmann, Krefeld, DT;
Wolfgang Rambold, Krefeld, DT;
Bayer Aktiengesellschaft, Leverkusen, DT;
Abstract
A process for the production of chromium oxide green pigment comprising heating a mixture of ammonium dichromate with at least the stoichiometrically equivalent quantity of a sodium salt selected from the group consisting of chloride and sulfate over a period of at most about 15 minutes to a pigment-forming temperature of about 800 to 1100.degree. C in the presence of about 1 to 45% water based on the weight of the mixture, calcining the mixture at a temperature in the above-mentioned range, and separating the formed pigment from the salts. The mixture may be formed in situ by reaction of sodium dichromate with ammonium chloride or sulfate in the presence of water. The presence during calcining of organic modifiers such as sawdust or of boron compounds such as borax increases, tinting strength and disproportionately affect color. The pigments are brighter, and of higher tinting strength than heretofore produced.