Gray-black encapsulated pigments and method for their preparation

US5019169A · kind A · utility

Assignee

• Degussa AG · DE

Inventors

• Dietrich Speer · Hanau, DE
• Akos Kiss · Alzenau, DE
• Peter Kleinschmit · Hanau, DE

Key dates

• Filing date: Mar 2, 1990
• Grant date: May 28, 1991
• Expiry date: Mar 2, 2010

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01P2002/08
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

Gray-black pigments are prepared by encapsulating iron titanates of formula FeTiO.sub.3 in zirconium silicate crystals. Manufacture is by calcining a mixture of zirconium oxide having a particle size distribution of 6 to 10 .mu.m and a specific surface area of 2 to 5.2 m.sup.2 /g, silicon dioxide and iron and titanium oxides or Fe and Ti compounds forming oxides in the presence of mineralizers under oxidizing conditions at 800 to 1300.degree. C. Finely divided FeTiO.sub.3 can also be used.