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:
Aug. 21, 1984
Filed:
Feb. 18, 1983
Wolfgang Habermann, Mainz, DE;
Peter Hammes, Ruppertsberg, DE;
Joachim Felger, Walheim, DE;
Karl-Ludwig Hock, Ludwigshafen-Ruchheim, DE;
Friedrich Brunnmueller, Ludwigshafen, DE;
Helmut Knittel, Ludwigsburg, DE;
Joachim Kranz, Ludwigshafen, DE;
Rolf Schneider, Mannheim, DE;
Peter Thoma, Frankenthal, DE;
BASF Aktiengesellschaft, Ludwigshafen, DE;
Abstract
Blue iron hexacyanoferrate-III pigments are produced by a process wherein complex iron-II hexacyanoferrate-II (Berlin white) is prepared by electrolysis of an aqueous catholyte solution containing (a) an iron-II salt, (b) an alkali metal salt, an ammonium salt or a mixture of these, and (c) hydrogen cyanide, in an electrolysis cell in which the anode chamber and cathode chamber are separated by an ion exchange membrane, using an electrically conductive aqueous liquid in the anode chamber, and the iron-II hexacyanoferrate-II obtained is then converted to the blue pigment. The process gives Berlin white, which is substantially free from salt, in high yield and high purity. Pollution caused by the process is very low, since only a small amount of salt is produced. Compared with the corresponding blue pigments produced by prior art processes, the pigments obtained give purer colorations with better gloss, and are of higher color strength.