Tdk Corporation

Tdx Corporation

Tohru Shimozawa

Masaharu Nishimatsu

Toshiaki Ide

A magnetic recording medium comprising a non-magnetic substrate, a magnetic recording layer formed on one side of the substrate and a back coating layer formed on the other side of the substrate, wherein the back coating layer contains an inorganic pigment having a Mohs hardness of at least 5 and carbon black, and the inorganic pigment is in an amount of at most 1/9 by weight relative to the carbon black.

Magnetic recording medium

A magnetic recording medium comprising a non-magnetic substrate, a magnetic recording layer formed on one side of the substrate and a back coating layer formed on the other side of the substrate, characterized in that the back coating layer is a radiation-cured coating layer containing a fine particulate pigment having an average particle size of the primary particles of at most 50 m.mu.m and a specific surface area of at least 35 m.sup.2 /g as measured by BET method.

A magnetic recording medium comprising a non-magnetic substrate, a magnetic recording layer formed on one side of the substrate and a back coating layer formed on the other side of the substrate, wherein said back coating layer contains graphitized carbon black having an average particle size of from 10 to 50 m.mu.m as measured by an electron microscope.

A magnetic recording medium comprising a non-magnetic substrate, a magnetic recording layer formed on one side of the substrate and a back coating layer formed on the other side of the substrate, characterized in that the back coating layer contains carbon black having an ash content of at most 0.05%, a specific surface area of from 20 to 350 m.sup.2 /g, an oil absorption of at most 200 ml/100 g and an average particle size of from 13 to 60 m.mu.m.

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Saku, Japan

Tohru Shimozawa