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:
Apr. 29, 1986
Filed:
Apr. 04, 1985
Applicant:
Inventors:
Konrad Opitz, Liederbach, DE;
Gunther Schwaiger, Frankfurt am Main, DE;
Assignee:
Hoechst Aktiengesellschaft, , DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C09B / ;
U.S. Cl.
CPC ...
8527 ; 8549 ; 8685 ; 534575 ; 534618 ; 534652 ;
Abstract
A process is described for separating sodium sulfate from aqueous solutions, containing less than 2% by weight of chloride, of certain fiber-reactive copper-formazan dyestuffs wherein this dyestuff solution is cooled down to a temperature between +5.degree. C. and -15.degree. C. In the course of the cooling the sodium sulfate precipitates in the form of the decahydrate and can be separated off in conventional manner, for example by filtration. The products obtained in this way are liquid low-salt aqueous copper-formazan dyestuff preparations which contain less than 4% by weight of sodium sulfate.