JPS6484416A - Disk-shaped magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve the dispersibility of magnetic powder as well as electromagnetic conversion characteristics and durability in and under a wide range of service environment and conditions by incorporating a specific resin and ferromagnetic material particles having a prescribed BET value into the binder of a magnetic layer. CONSTITUTION:The magnetic layer is formed by incorporating the vinyl chloride resin having at least one kind of acid groups or the acid groups forming the salts thereof as well as an epoxy group and hydroxyl group into the binder resin of the above-mentioned magnetic layer, incorporating the ferromagnetic particles having 15-25m<2>/g BET value into said resin, kneading and dispersing the mixture and coating the mixture on a nonmagnetic substrate. The ferromagnetic powder is preferably gamma-iron oxide, Co-deposited=gamma-iron oxide, iron, etc. The BET value is 15-25m<2>/g and the axial ratio of acicular particles is preferably 3-15, more particularly preferably 5-9. The acid groups to be introduced into the vinyl chloride resin are preferably a sulfo group, phospho group and carboxyl group. The metals for forming the salts are preferably Li, K and Na.