Patent · US Expired

Process for the preparation of pigments containing Cr.sub.2 O.sub.3

US5167708A · kind A · utility

7Cited by

2References

4Claims

0Family size

Assignee

BAYER HEALTHCARE LLC · DE

Inventors

Volker Wilhelm · Bensberg, DE
Dieter Messer · Odenthal, DE

Key dates

Filing date	Mar 23, 1992
Grant date	Dec 1, 1992
Priority date	—
Expiry date	Mar 23, 2012

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC01P2002/32
WIPO fieldBasic materials chemistry
WIPO sectorChemistry

Abstract

A process for the preparation of chromate-free, Cr.sub.2 O.sub.3 -containing pigments having a spinel, haematite or corundum structure comprises blending pigment-forming raw materials corresponding to the Cr.sub.2 O.sub.3 -containing pigments with from 0.5 to 10% by weight of boric acid or phosphoric acid, calculated as B.sub.2 O.sub.3 or P.sub.2 O.sub.5, respectively, and then annealing the blend whereby the chromate-free, Cr.sub.2 O.sub.3 -containing pigment is obtained.

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