| 摘要 |
PURPOSE:To improve the electromagnetic transducing characteristics and durability by forming a magnetic layer on one side of a nonmagnetic support and a back layer contg. fine-grained carbon black of a specified grain size, coarse- grained carbon black of a specified grain size and inorg. powder in a specified ratio to a binder on the other side. CONSTITUTION:A magnetic layer is formed on one side of a nonmagnetic support, and a back layer of <=2mum thickness on the other side. The back layer contains fine-grained carbon balck of 10-30mmu average grain size and coarse- grained carbon black of 150-500mmu average grain size in 99.5:0.5-60:80 ratio and further contains inorg. powder of CaCO3, SiO2 or the like by 0-10pts.wt. per 100pts.wt. carbon black. The weight ratio of the carbon black and the inorg. powder to a binder is adjusted to 1/10.5-1/3.5. A magnetic recording medium having a low coefft. of friction, high traveling durability and a high S/N ratio and suitable for use especially as a VHS type videotape is obtd. |
