| 摘要 |
PURPOSE:To obtain a magnetic recording medium having high electromagnetic conversion characteristics and physical characteristics by using a copolymer consisting of vinyl chloride, vinyl ester of alkylcarboxylic acid, a monomer copolymerizable with vinyl chloride, and a saponification product of vinyl ester of alkylcarboxylic acid as an impregnating agent for nitrocellulose. CONSTITUTION:Nitrocellulose is impregnated with a quaternary vinyl chloride- vinyl acetate type copolymer. For example, 10kg nitrocellulose impregnated with 30% isopropyl alcohol, 0.5-12kg quaternary vinyl chloride-vinyl acetate type copolymer [the absorption ratio of OH/CH: 0, 0.2, 0.3, 0.5, 0.7 or 0.9, and the monomer (maleic acid) content: 0, 0.5, 1.0, 1.5, 2.0, 2.5 or 3.0(%)], and methyl ethyl ketone are kneaded with a kneader to mix the nitrocellulose with the copolymer. The amount of the methyl ethyl ketone is 15% of the total amount of the resins. The mixture is formed into a resin sheet with a heat roll at 30-40 deg.C while evaporating the solvent, and the residual solvent is evaporated at room temp. The resulting sheet is crushed to form chips. |
