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:
Jul. 23, 1985
Filed:
Sep. 01, 1982
Kabushiki Kaisha Ueno Seiyaku Uno Kenkyujo, Osaka, JP;
Abstract
The color of azo pigments derived from 2-hydroxynaphthalene-3-carboxylic acid or its salts are improved by the coupling reaction of a diazonium compound of an aromatic aminosulfonic acid with a coupling component which is a mixture of (1) 2-hydroxynaphthalene-3-carboxylic acid or its salt, (2) .beta.-naphthol or its salt, and (3) a phenolic by-product having a molecular weight of about 300 and containing about 1 equivalent of phenolic hydroxy groups. The phenolic by-product can be obtained by evaporating .beta.-naphthol from a tarry substance formed as a by-product during the reaction of an alkali .beta.-naphtholate with carbon dioxide, extracting the residue with an alkali and precipitating the soluble matter with an acid. The color or tone of the azo pigment is stabilized by the use of the coupling component. The azo pigments range from those having dark color and a greater degree of transparency which are suitable for use in printing inks to those having increased brightness which are suitable for use in paints.