| 摘要 |
PURPOSE:To obtain a titled recording medium having high S/N and suitable for high-density recording by incorporating magnetic powder having >= about 28m<2>/g specific surface and granular alpha-Fe2O3 having about 0.05-1mum mean particles size into a magnetic layer. CONSTITUTION:Magnetic powder consisting of fine particles and having >=28m<2>/g specific surface (BET value) is used as the magnetic powder in a magnetic layer and granular alpha-Fe2O3 having about 0.05-1mum mean particle size is incorporated into the magnetic layer. For example, the mixture of 300pts. wt. Co-coated gamma-Fe2O3, 38pts.wt. vinyl chloride-vinyl acetate copolymer, 24pts.wt. polyurethane resin, 7pts.wt. stearic acid, 1pts.wt. silicone oil, a specific amt. of granular alpha-Fe2O3 having specific size and 800pts.wt. mixed solvent contg. the same amt. of methyl ethyl ketone and toluene is mixed and dispersed in a ball mill for 40hr. The obtained magnetic paint is then coated on a base film to make a magnetic film.
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