Process for preparing copper phthalocyanine pigments of the .alpha.-modification

US3984433A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Ernst Spietschka · Idstein, DE
• Siegfried Schiebler · Bad Soden am Taunus, DE
• Wolfgang Tronich

Key dates

• Filing date: Dec 21, 1973
• Grant date: Oct 5, 1976
• Expiry date: Dec 21, 1993

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/31678
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

A process for preparing very pure copper phthalocyanine pigments of the .alpha.-modification, wherein substituted or unsubstituted copper phthalocyanines having different degrees of purity are converted into copper phthalocyanine salts capable of being isolated, with the aid of suitable acids which dissolve the impurities contained in the dyestuff, wherein these salts are separated from the acid, the copper phthalocyanines of the .alpha.-modification are set free in a pure form from the copper phthalocyanine salts by the action of water and wherein the isolated copper phthalocyanine is subject in an aqueous suspension to a mechanical fine division. This process yields copper phthalocyanines of the .alpha.-modification in a very pure form without causing problems with respect to the waste water.