Magnetic recording medium comprising a polyoxyalkylene oxide binder, a phosphoric ester dispersant and a cicular magnetic powder

US5436070A · kind A · utility

Assignee

• BASF Magnetics GmbH · DE

Inventors

• Wolf-Dieter Schroer · Leverkusen, DE
• Attila Vass · Foster City, US
• Juergen Sauter · Munich, DE
• Juergen Schmidt · Goldkronach, DE
• Guenther Kuntz · Munich, DE

Key dates

• Filing date: Sep 26, 1994
• Grant date: Jul 25, 1995
• Expiry date: Sep 26, 2014

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/2998
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

A magnetic dispersion comprising finely divided iron power or iron alloy powder having a BET value of more than 35 m.sup.2 /g dispersed in a polymeric binder and organic solvent, whose filterability is markedly improved, is obtained by using certain low molecular weight phosphoric esters of the general formula I or II ##STR1## combined with a dispersion-active compound which contains at least one polar group capable of adsorption on the magnetic pigment. The polar group of the dispersion-active compound can be an acid or alkaline or amphoteric group or a group capable of hydrogen bonding or polarization. The dispersion-active compound can be a polycondensate, a polyaddition product or a chain growth copolymer which can also be used in the magnetic dispersion combined with customary other polymeric binders.