| 摘要 |
PURPOSE:To improve electromagnetic conversion characteristics, running stability and running durability by incorporating specific ferromagnetic powder, two kinds of binder resist and Al2O3 into a magnetic layer provided on a nonmagnetic base. CONSTITUTION:The ferromagnetic powder having 40m<2>/g specific surface area by a BET method is incorporated into the magnetic layer which is provided on the nonmagnetic base and consists essentially of the ferromagnetic powder and the binder. A vinyl chloride resin contg. the phosphate group expressed by the formula (M1, M2 are Na, K, Li, H, NR4 or NHR3, R is alkyl or H) as a functional group in the molecule as the 1st component and a functional group-contg. resin, except the vinyl chloride system, having -SO3M, -OSO3M, -COOM and >=1 kinds of the groups expressed by the formula (M, M1 and M2 are the same as mentioned above) in the molecule as the 2nd component are incorporated into the above-mentioned magnetic layer in such a manner that the weight ratio of the 1st component/2nd component attains 0.4-2.5. In addition, the Al2O3 having 0.1-0.5mum average grain size is incorporated therein. The higher density, smoother, surface, etc., of the magnetic recording medium are obtd. and the coefft. of friction of the medium surface is decreased by such constitution of the magnetic layer. |
