| 摘要 |
PURPOSE:To increase the durability of a magnetic recording medium by incorporating a phosphate deriv. into the magnetic layer contg. ferromagnetic metallic iron or alloy powder as a magnetic body. CONSTITUTION:When a magnetic coating material contg. ferromagnetic metallic iron or alloy powder as a magnetic body is coated on a nonmagnetic support to form a magnetic layer, a phosphate deriv. is incorporated into the magnetic layer. When an active metallic surface appears even during the preparation of the coating material, the phosphate deriv. adsorbs on the surface to form a protective film, so the durability of the resulting magnetic tape is improved. Tricresyl phosphate, triphenyl phosphate or the like is used as the phosphate deriv., and the amount of the phosphate deriv. to be added is only 0.1-5pts.wt. of the amount of the magnetic powder. In case of <0.1pts.wt., the effect is not produced, and in case of >6pts.wt., the phosphate deriv. rises to the surface of the coated magnetic film. |
