.beta.-modified crystalline red pigment

US4719292A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Franz Schui · Frankfurt am Main, DE
• Reinhold Deubel · Bad Soden am Taunus, DE
• Norbert Wester · Hofheim, DE

Key dates

• Filing date: Jun 23, 1983
• Grant date: Jan 12, 1988
• Expiry date: Jun 23, 2003

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C09B63/00
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

A novel crystallographic modification (.beta.-modification) of the pigment C. I. Pigment Red 53:1 is described and claimed which has characteristic reflection values in its X-ray diffraction pattern obtained by means of Cu-K.sub..alpha. radiation. This novel pigment form is obtained by reacting an aqueous solution of an alkali metal or ammonium salt of the formula 1 ##STR1## with the equivalent amount of a water-soluble barium salt in the presence of a compound of the formula 2 ##STR2## The modification is distinguished by a more yellowish-red shade as compared to the known .alpha.-modification.