MAGNETIC RECORDING MEDIUM AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To inhibit the rise of the viscosity of a coating material for a nonmagnetic underlayer and to enhance surface smoothness by using iron oxide hydrate surface-treated with an organic compound having terminal carboxyl groups as nonmagnetic particles contained in the nonmagnetic underlayer consisting essentially of the particles and a binder. SOLUTION: A nonmagnetic underlayer 2 and a magnetic recording layer 3 are successively formed on each of both faces of a nonmagnetic substrate 1. The magnetic recording layer 3 is formed by coating the top of the nonmagnetic underlayer 2 with a coating material for the magnetic recording layer containing a magnetic power dispersed in an organic binder or the nonmagnetic underlayer 2 and the magnetic recording layer 3 are simultaneously formed by double-layer coating. The nonmagnetic underlayer 2 contains iron oxide hydrate surface-treated with an organic compound having terminal carboxyl groups and a binder as essential components and preferably contains carbon black.