MAGNETIC RECORDING MEDIUM

摘要

PURPOSE:To obtain adequate resilience and substantial durability by incorporating ferromagnetic powder of which the surface is treated with the salt of a copolymer consisting of a polycarbonate urethane resin and monomer unit having at least one electromagnetic layer. CONSTITUTION:The ferromagnetic powder of which the surface is treated with the salt of the copolymer consisting of the polycarbonate urethane resin and the monomer unit having at least one electro-negative org. group as the constituting component is incorporated into the magnetic layer 2. The polycarbonate urethane resin is used as the binder resin for the layer. The wear resistance intrinsic to the urethane resin is provided; in addition, the heat resistance is improved by the presence of the carbonate component and the running stability is obtd. by the decreased coefft. of friction. The solubility into a solvent is improved and the film strength can be increased by increasing the concn. of the urethane. The surface of the magnetic powder is preliminarily treated with the salt of the copolymer and therefore the magnetic powder is satisfactorily dispersed into the polycarbonate urethane resin.