| 摘要 |
PURPOSE:To obtain the titled recording medium having a highly durable layer, superior in a light shielding property and having an excellent electromagnetic transducing characteristic by incorporating granular alpha-Fe2O3 having about 0.05-1mum mean particle size, carbon black and a vinyl chloride-vinyl alcohol copolymer into the magnetic layer. CONSTITUTION:A vinyl chloride-vinyl alcohol copolymer is used as a binder component. Granular alpha-Fe2O3 (about 0.05-1mum mean particle size) and carbon black are mixed into a magnetic layer consisting of a vinyl chloride-vinyl alcohol copolymer, etc. For example, the mixture of 100pts.wt. Co-contg. gamma-Fe2O3 having about 28-30m<2>/g specific surface, 10pts.wt. vinyl chloride-vinyl alcohol- vinyl acetate copolymer, 10pts.wt. granular gamma-Fe2O3 having about 0.3mum mean particle size, 8pts.wt. carbon black having 120 staining power and 230pts.wt. mixed solvent consisting of the same amt. of methyl ethyl ketone, toluene and methyl isobutyl ketone is mixed and dispersed in a sand mill to form a magnetic paint. An isocyanate curing agent is added to the paint and the mixture is coated on a tape to make a magnetic tape.
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