Thermostable iron oxide pigments, processes for their preparation and their use

US4913063A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Friedrich Jonas · Aachen, DE
• Peter Schick · Eßlingen, DE
• Jurgen Wiese · Krefeld, DE

Key dates

• Filing date: Jul 25, 1988
• Grant date: Apr 3, 1990
• Expiry date: Jul 25, 2008

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01P2006/19
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

Improved iron oxide pigments useful in the manufacture of magnetic recording carriers or for coloring inorganic or organic materials are iron oxide pigments having an iron (II) content of at least 5% by weight calculated as FeO after-treated with a phenolic compounds of the formula ##STR1## wherein X is O or NH, and PA1 R is straight chained or branched alkyl with 1 to 30 carbon atoms, alkenyl with 2 to 30 carbon atoms, cycloalkyl with 5 to 12 carbon atoms, or hydrogen.