Patent · US Expired

Grayish-black encapsulated pigments and method of their production

US5008223A · kind A · utility

20Cited by

4References

8Claims

0Family size

Assignee

Degussa AG · DE

Inventors

Dietrich Speer · Hanau, DE
Akos Kiss · Alzenau, DE
Peter Kleinschmit · Hanau, DE
Juergen Hanich · Frankfurt, DE

Key dates

Filing date	Mar 2, 1990
Grant date	Apr 16, 1991
Priority date	—
Expiry date	Mar 2, 2010

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC01P2006/12
WIPO fieldBasic materials chemistry
WIPO sectorChemistry

Abstract

The grayish-black encapsulated pigments contain carbon black particles with specific surface areas of 10 to 1000 m.sup.2 /g (BET) encapsulated in colorless crystals of zirconium silicate. In order to produce the pigments, mixtures of zirconium oxide with a particle size distribution (D50 values) between 7 and 10 .mu.m and a spec. surface between 2 and 4 m.sup.2 /g, silicon oxide, carbon black and mineralizers are heated under reducing conditions to 900.degree. to 1400.degree. C. and calcined for 0.5 to 8 hours and recalcined under oxidizing conditions to remove the non-included carbon black. The encapsulated pigments of the invention are suitable for the pigmented coloration of glazes.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.