| 摘要 |
PURPOSE:To obtain a long-life vertical magnetic recording medium which obviates the exfoliation of a magnetic alloy layer from a substrate by forming a ferromagnetic alloy layer on the surface of the substrate whose the ratio of the residual solvent incorporated into a high-polymer film to be used for the substrate of the magnetic recording medium is specified to a specific value or below. CONSTITUTION:The substrate 1 is subjected to a heating treatment in a vacuum or atm. to remove the solvent remaining in the stage of producing the high-polymer film consisting of polyethylene terephthalate, polyimide, etc. to <=0.7wt% when said film is used as the substrate. The treated film is used as the substrate and the ferromagnetic alloy layer 2 consisting of a Co-Cr alloy, etc. is first formed on one or both surfaces (both surfaces in the figure) by orienting the axis of easy magnetization in the direction perpendicular to the layer plane by a sputtering method, etc. A protective film 3 consisting of Al2O3, etc., and a lubricating layer 4 consisting of fluorocarbon, etc. are then provided on the layer 2. The residual solvent of the substrate 1 is decreased and the weakened adhesive strength as a result of the bleeding of the solvent onto the surface by the effect of the heat in the stage of forming the magnetic layer 2 is obviated. The long-life recording medium which obviates the exfoliation of the layer 2 during use is thus obtd.
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