| 摘要 |
PURPOSE:To improve the durability, magnetic characteristic, and electromagnetic transducing characteristic of the titled medium by incorporating an acrylic ester copolymer having a quaternary ammonium salt in the molecule into the magnetic layer as a binder. CONSTITUTION:A magnetic layer consisting essentially of ferromagnetic powder and a binder is formed on a nonmagnetic carrier to obtain the magnetic recording medium. The binder contains the acrylic ester copolymer having a quaternary ammonium salt in the molecule as a binding agent. An acrylic ester copolymer consisting essentially of an acrylic ester and obtained by introducing a quaternary ammonium salt into so-called acrylic rubber as a polar group is used as the acrylic ester copolymer to be used as the binder of the magnetic layer. Acrylic rubber is highly elastic and resistant to shock and has excellent resistance to water and oil. Moreover, the adhesion to the base film as the nonmagnetic carrier is excellent. The content of the acrylic ester is controlled to 95-50wt%. Consequently, the durability and surface property of the magnetic recording medium are improved, and further the electromagnetic transducing characteristic is extremely ameliorated.
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