| 摘要 |
A magnetic recording medium excellent in electromagnetic characteristics and running durability and a method for producing the same are disclosed, the magnetic recording medium comprising a non-magnetic support and a magnetic layer formed thereon, the magnetic layer containing a magnetic alloy powder and a binder, wherein said magnetic alloy powder has a length in the long axis of 2,000 ANGSTROM or less and a saturation magnetization ( sigma s) of 100 emu/g or more; said binder contains a vinyl chloride copolymer, a polyisocyanate, and a polyurethane resin, wherein the polyurethane resin has at least 3 hydroxyl groups per molecule and at least 1x10-5 eq/g of at least one type of polar group selected from the group consisting of -SO3M, -OSO3M, -COOM, -PO(OM')2 and -OPO(OM')2 (wherein each of M and M' represents a hydrogen atom, an alkali metal or ammonium ion) and the polyurethane resin is used in an amount equal to or more than by weight that of the polyisocyanate, and wherein the vinyl chloride copolymer has at least 1x10-5 eq/g of at least one type of polar group selected from the group consisting of -SO3M, -OSO3M, -COOM, -PO(OM')2 and -OPO(OM')2 (wherein each of M and M' represents a hydrogen atom, an alkali metal or ammonium ion); and a Kerr rotational angle measured at a surface of the magnetic layer is 5 minutes or more.
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