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:
Jun. 28, 1983
Filed:
Mar. 26, 1981
Beat Bruttel, Bockten, CH;
Heinz Pfenninger, Lupsingen, CH;
Ciba-Geigy Corporation, Ardsley, NY (US);
Abstract
A process for producing solid dye compositions, which process comprises passing an aqueous solution or suspension of at least one water-soluble crude dye, to effect separation of synthesis by-products having a molecular weight of below 500 and partial separation of water, through a semipermeable membrane, subsequently drying the resulting aqueous preparation which has become more highly concentrated, and optionally adding further additives before and/or after passage of the aqueous solution or suspension through the semipermeable membrane, these additives being added beforehand only when they do not become separated by the membrane. There are obtained by this process low-dust to dust-free compositions which are distinguished by high mechanical strength, high bulk density, free-flowing characteristics and good dissolving behavior. Employing these compositions it is possible to prepare low-foam to foam-free aqueous dye liquors having very good solution stability, even in the presence of electrolytes.