Patent · US Expired

Magnetic recording medium and method of stabilization of chromium dioxide magnetic pigments

US4275114A · kind A · utility

4Cited by

1References

6Claims

0Family size

Assignee

BASF SE

Inventors

Eduard Schoenafinger
Herbert Motz · Beindersheim, DE
Manfred Ohlinger · Bischofswerda, DE
Paul Deigner · Bad Dürkheim, DE
Werner Grau · Frankenthal (Pfalz), DE

Key dates

Filing date	Mar 10, 1977
Grant date	Jun 23, 1981
Priority date	—
Expiry date	Mar 10, 1997

Classification

Technology area (CPC Y)Emerging Cross-Sectional Technologies
CPC primaryY10T428/31663
WIPO fieldBasic materials chemistry
WIPO sectorChemistry

Abstract

Chromium dioxide magnetic pigments are stabilized against loss of their magnetic properties by treating them, in aqueous and/or alcoholic suspension, with a block copolymer consisting of siloxane units and alkyleneoxy units of 2 to 4 carbon atoms, the alkyleneoxy units being bonded to the polysiloxane radical by a Si--O--C or Si--C group, in an amount of from 1 to 40% by weight based on the chromium dioxide, after which the latter is separated off and dried at from 50.degree. to 200.degree. C. The stabilized chromium dioxide magnetic pigments may be used for the manufacture of magnetic recording media exhibiting improved stability of the magnetic properties under adverse climatic conditions.

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