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Magnetic recording medium

  • US 4,784,907 A
  • Filed: 12/22/1986
  • Issued: 11/15/1988
  • Est. Priority Date: 12/20/1985
  • Status: Expired due to Term
First Claim
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1. A magnetic recording medium comprising a non-magnetic support and a magnetic recording layer provided on the support, said magnetic recording layer comprising a binder and a ferromagnetic powder dispersed therein, which is characterized in that:

  • said magnetic recording layer comprises a fatty acid ester lubricant and a lubricant other than the fatty acid ester lubricant;

    said binder is composed of a resin component comprising a vinyl chloride copolymer resin containing a repeating unit which has a polar group and having a glass transition point of not lower than 50°

    C. and a polyurethane resin containing a repeating unit which has a polar group and having a glass transition point of lower than 50°

    C., a ratio by weight of said vinyl chloride copolymer resin to said polyurethane resin being in the range of 70/30 to 30/70; and

    at least one resin of said resins contains a repeating unit having at least one polar group selected from the group consisting of --SO3 M, --OSO3 M and --PO(OM'"'"')2, wherein M is hydrogen or an alkali metal atom, and M'"'"' is hydrogen, an alkali metal atom or a lower hydrocarbon group.

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