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. 18, 1985
Filed:
Dec. 12, 1983
Roger Lacroix, Village-Neuf, FR;
Ciba-Geigy Corporation, Ardsley, NY (US);
Abstract
The invention describes a process for the preparation of stable aqueous solutions of water-soluble reactive dyes, starting from an aqueous solution or suspension of the crude reactive dye which is concentrated and at least partially desalted by a membrane separation process. The process of the invention comprises continuously replacing part of the water which is drawn off from the dyestuff solution or suspension during the membrane separation process with demineralized water, whereby the concentration of calcium and magnesium ions in the dyestuff solution does not exceed 0.01% by weight. The concentrated and desalted dyestuff solution is stabilized by addition of a polyphosphate or dihydrogen phosphate/polyphosphate buffer, and a component which improves the water-solubility of the dye is optionally added. The formulations so obtained are readily storable for several months in the temperature range from -10.degree. to +40.degree. C.