| 摘要 |
PURPOSE:To improve the magnetic and mechanical characteristics of the titled medium by coating a magnetic layer contg. magnetic powder almost the whole surface of which is covered with a monomolecular layer consisting essentially of acylated lecithins, a necessary binder, etc., on a nonmagnetic carrier. CONSTITUTION:A magnetic layer consisting of magnetic powder almost the whole surface of which is covered with a monomolecular layer consisting essentially of a mixture of acylated lecithins, a desired binder, etc., is coated on a carrier. Animal and plant lecithins such as yolk lecithin, soybean lecithin, rate seed lecithin, etc., are exemplified as the material of the mixture of acylated lecithins. When the content of impurities such as oil and fatty acids in the mixture of acylated lecithins is low, a greater effect can be obtained. When the content of oil, etc., in high-purity lecithins is regulated to <=5%, the effect is enhanced. Acylation is conducted by dissolving the lecithin in one or <=2 kinds of solvents such as hexane and benzene and the lecithins are allowed to react with an acylating reagent at 50-150 deg.C. Consequently, the magnetic and mechanical characteristics are improved.
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