| 摘要 |
<p>A magnetic recording medium has a magnetic layer consisting essentially of a binder and magnetic particles on one surface of a non-magnetic substrate. The thermoplastic polyurethane-urea resin in which unsaturated bonds sensitive to radiation are introduced is used as the binder.</p><p>The thermoplastic polyurethane-urea resin in which the radiation-sensitive unsaturated bonds are introduced has both urethane and urea bonds in the molecular structure thereof. It is synthesized from long chain diol with a molecular weight of approximately 500 to 5000, a short chain diol with a molecular weight of approximately 50 to 500, an organic diisocyanate, an organic diamine, and a compound containing radiation-sensitive unsaturated double bonds, and cured by radiation.</p><p>The thermoplastic polyurethane-urea resin in which not only the radiation-sensitive double bonds but also hydrophilic polar groups are introduced may also be used as the binder. These hydrophilic polar groups may for example include -S0<Sub>3</Sub>M, -OS0<Sub>3</Sub>M, -COOM, and
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