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. 14, 1977
Filed:
Aug. 06, 1975
Applicant:
Inventors:
Karlheinz Neisius, Darmstadt, DT;
Wilhelm Baumer, Darmstadt, DT;
Assignee:
E. Merck A. G., Darmstadt, DT;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01N / ; G01N / ;
U.S. Cl.
CPC ...
252408 ; 2325 / ; 260200 ; 428411 ;
Abstract
In colorimetric indicators comprising a carrier such as cellulose saturated with one or more azo dyes having reactive groups capable of forming a chemical bond with the carrier material, the improvement wherein the indicator is made non-bleeding by using such dyes which, in addition to the reactive group, contain at least one additional sulfonic acid and/or carboxylic acid group, an example of such a dye being 4-anilino-3'-(2-hydroxysulfonyloxyethylsulfonyl)-azobenzene-6'-carboxylic acid.