| 摘要 |
PURPOSE:To improve running durability and adhesiveness by incorporating specific zinc oxide, carbon black, oxide or carbonate of the II groups element of periodic table and resin binder into a back coating layer of a magnetic recording medium. CONSTITUTION:A back coat layer of a magnetic recording medium is formed of a coated film contg. zinc oxide having <=500mmu average grain size, carbon black having 10-100mmu average grain size, oxide or carbonate of the II group element of periodic table having <=500mmu average grain size and 5 Moh's hardness and a resin binder. The ratio of the zinc oxide and the resin binder is adequately in the range of 30-300pts.wt. zinc oxide with respect to 100pts.wt. the resin binder and the ratio of the oxide or carbonate of the II group element of periodic table having <=5 Moh's hardness is preferably made 1:9-9:1. The carbon black required for decreasing electric resistance is >=10%. |
