| 摘要 |
PURPOSE:To obtain a magnetic recording medium which hardly generates flaws on the surface of a magnetic layer, decreases the generation of drop-outs and is less deteriorated in the S/N characteristic of the magnetic material by providing a back coat layer contg. carbon black and inorg. filler having a prescribed particle size and harness on the surface of a base on the side opposite from the magnetic layer. CONSTITUTION:The magnetic layer is provided on the nonmagnetic substrate and the back coat layer consisting of the carbon black and a binder dispersed with the inorg. filler particles is formed on the surface of the base on the side opposite therefrom. The thickness of the back coat layer is <=0.6mum and the average grain size of the inorg. filler particles is smaller than the layer thickness of the back coat layer and >=1/5 the layer thickness of the back coat layer. The max. particle size thereof is <=11/10 the thickness of the back coat layer. The Mohs' hardness of said particles is >=5. For example, chromium dioxide, alpha-alumina, titanium dioxide, silicon oxide, etc., are used for said particles. |
