| 摘要 |
PROBLEM TO BE SOLVED: To provide a magnetic recording medium having excellent dispersibility of ferromagnetic powder, and excellent electromagnetic conversion characteristics, running performance, storage stability at high temperature, and still durability. SOLUTION: The magnetic recording medium has at least one magnetic layer in which ferromagnetic powder and a binder are dispersed is provided on a substrate via an underlying layer or directly. The binder of the magnetic layer includes a polyurethane obtained by causing materials including a polyester polyol, a chain extender, and an organic diisocyanate to react. The ferromagnetic powder includes cobalt-containing iron as a main component and yttrium. The polyurethane includes an aliphatic dibasic acid in the polyester polyol. A diol component incudes an aliphatic diol component having a cyclic structure-free alkyl branched side chain. The chain extender includes an aliphatic diol having an alkyl branched chain. The underlying layer binder includes a chain extender having a polyol having an ether group and a diol having a cyclic structure in the polyurethane, and an organic diisocyanate. COPYRIGHT: (C)2007,JPO&INPIT
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