| 摘要 |
PROBLEM TO BE SOLVED: To obtain a two-layered MP(metal particle) type magnetic recording medium having superior mechanical characteristics such as running performance and durability while reducing the thickness and surface roughness of the magnetic layer to levels comparable to those of the magnetic layer of an ME(metal evaporation) type magnetic recording medium. SOLUTION: A nonmagnetic coating film is formed on a PET film with a nonmagnetic coating material prepd. by blending a mixed solvent consisting of methyl ethyl ketone, toluene and cyclohexanone with PVC resin, polyurethane resin, acicular goethite powder having 0.10μm major axis size and an acicularity ratio of 15, granular iron oxide having an axial ratio of 1.5, carbon black, stearic acid, n-butyl stearate and a polyisocyanate. A magnetic coating film is formed on the nonmagnetic coating film with a magnetic coating material prepd. by blending a mixed solvent consisting of methyl ethyl ketone, toluene and cyclohexanone with PVC resin, polyurethane resin and ferromagnetic metal powder having 0.08μm major axis size, an acicularity ratio of 10, 180kA/m coercive force and 0.18T saturation magnetization. Orientation in a magnetic field, drying and calendering are then carried out.
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