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:
May. 16, 1995
Filed:
May. 10, 1993
Iwao Sakaguchi, Hyogo, JP;
Katsutoshi Numano, Osaka, JP;
Toshiaki Kishimoto, Osaka, JP;
Hiroki Inoue, Osaka, JP;
Yoshiaki Hayashi, Osaka, JP;
Keisuke Ito, Osaka, JP;
Sumitomo Chemical Co., Ltd., Osaka, JP;
Abstract
4,4'-Diamino-1,1'-dianthraquinonyl compounds which are obtained in a known manner and which are easy to agglomerate or aggregate owing mainly to their too fine particle size are conditioned by heating an aqueous suspension consisting essentially of the 4,4'-diamino-1,1'-dianthraquinonyl compound and water in the presence or absence of a mineral acid or an alkali. The thus obtained 4,4'-diamino-1,1'-dianthraquinonyl pigments are used in paints, printing inks, coloring of plastics and the like. The aqueous suspension is preferably prepared by desulfonating a 4,4'-diamino-1,1'-dianthraquinonyl-3,3'-disulfonic acid compound in a mineral acid such as sulfuric acid and then mixing the desulfonation reaction mixture with water or by once isolating the resulting 4,4'-diamino-1,1'-dianthraquinonyl compound and mixing the isolated compound with water.