| 摘要 |
PURPOSE:To obtain the titled recording medium having a highly durable magnetic layer, superior in a light shielding property and having an excellent electromagnetic transducing characteristic by incorporating granular alpha-Fe2O3, carbon black, TiO2 and a vinyl chloride-vinyl alcohol copolymer into the magnetic layer. CONSTITUTION:A vinyl chloride-vinyl alcohol copolymer is used as the binder component. Granular alpha-Fe2O3, carbon black and TiO2 are mixed into a magnetic layer consisting of the vinyl chloride-vinyl alcohol copolymer, etc. For example, 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. polyurethane resin, 2pts.wt. lubricant, 2ptw.wt. carbon black having 100 staining power, 3pts. wt. TiO having about 0.2mum mean particle diameter, 10pts.wt. granular alpha-Fe2O3 and 250pts.wt. mixed solvent consisting of the same amt. of methyl ethyl ketone, toluene and methyl isobutyl ketone are mixed and dispersed in a sand mill to prepare a magnetic paint. An isocyanate curing agent is added to the magnetic paint and uniformly mixed and the mixture is coated on a tape to make a magnetic tape.
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