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:
Feb. 28, 1989
Filed:
Sep. 15, 1986
Applicant:
Inventors:
Assignee:
Mitsubishi Chemical Industries Limited, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C09B / ; C09B / ;
U.S. Cl.
CPC ...
8527 ; 8620 ; 8680 ; 8937 ;
Abstract
In accordance with this invention an aqueous solution of a water-soluble dye containing lithium sulfonate group or ammonium sulfonate group can be obtained by a very simple and economical process in such a way that an aqueous solution of a water-soluble dye containing sodium sulfonate group is fed to a packed column packed with acid type cation exchange resin (H-form) to form an aqueous solution of a dye containing a free sulfonic acid group, and after neutralizing the resulting solution with LiOH or NH.sub.4 OH, the aqueous solution of the dye thus obtained is concentrated according to a process for separation through reverse osmotic membrane.