MAGNETIC RECORDING MEDIUM

摘要

PURPOSE:To obtain a back layer having excellent smoothness of a coated film, traveling property and wear resistance by mixing carbon black of a thermal black type having 60-200mum average grain size and fine silica powder and incorporating the mixture composed thereof as a nonmagnetic powder component in the back coating layer into said layer. CONSTITUTION:The carbon black of the thermal black type having 60-200mum average grain size and the fine silica powder are incorporated as the nonmagnetic powder component in the back coating layer into said layer. The carbon black has the lower effect of lowering the coefft. of friction when the average grain size thereof is <=60mum. The smoothness of the coated film is lost when the average grain size is >=200mum. The carbon black of nearly spherical thermal system having no structure construction permits uniform dispersion into a binder and has a high effect of lowering the coefft. of friction. The fine silica powder is used in order to improve the wear resistance of the coated film of the back layer. The back layer which has the excellent repetitive traveling stability and the excellent antistatic and light shielding properties is thereby formed without impairing the electromagnetic conversion characteristic.