| 摘要 |
PURPOSE:To obtain good durability without impairing electromagnetic conversion characteristics by incorporating a specific binder at a prescribed ratio into a magnetic layer. CONSTITUTION:The binder of the magnetic recording medium provided with the magnetic layer essentially consisting of ferromagnetic metal powder having 40-60m<2>/g specific surface area by a BET method and binder on a nonmagnetic base consists of a -SO3M group-containing vinyl chloride copolymer (A), a -SO3M' group-containing polyurethane resin (B) and -COOM'' group-containing polyurethane resin (C) (M, M', M'' are a hydrogen atom or alkali metal), the weight ratios of which satisfy (A)/(B+C)=40/60-70/30, (A+B)/(C)=60/40-90/10 and in which both (B) and (C) of the total binder are >=10wt.%. The dispersibility of the ferromagnetic metal powder is thereby improved and travel ing flaws and sticking at the time of traveling are eliminated. The good durabil ity is thus obtd. without impairing the electromagnetic conversion characteristics.
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