Magnetic records medium having multiple magnetic layers for recording in long and short wavelength

摘要

A magnetic recording medium comprises a non-magnetic base material; a lower magnetic layer containing a magnetic powder for recording in a long wavelength range and a resin binder; an upper magnetic layer containing a magnetic powder for recording in a short wavelength range and a resin binder; and an intermediate layer disposed between the two magnetic layers. By properly selecting the type and amount of resin binder contained in the upper magnetic layer and by disposing the intermediate layer whose main component is a resin binder, dispersion property of the magnetic powder in the upper magnetic layer can highly be improved, and thin and smooth magnetic layers can be obtained. Thus, the recording medium provides excellent reproduction characteristics in the wide wavelength range and has excellent running durability. In particular, the reproduction characteristics in a short wavelength range can be improved. A hexagonal ferrite powder is suitably used as the magnetic powder for recording in the short wavelength range. As the resin binder for the intermediate layer, a polyisocyanate compound whose molecular weight is 1,000 or less is particularly effective.