Sughrue, Mion, Zinn, Macpeak & Seas
Magnetic recording medium
 An improved magnetic recording medium comprises a nonmagnetic support and a magnetic recording layer which comprises a ferromagnetic powder, a lubricant and an abrasive dispersed in a binder comprising a specific polyurethane resin and a specific vinyl chloride copolymer at a ratio (polyurethane resin:vinyl chloride copolymer) in the range of 15:85 to 90:10. The polyurethane resin has a polar group such as --COOM, --SO.sub.3 M, --OSO.sub.3 M and --PO(OM').sub.2, wherein M is hydrogen or an alkali metal atom, and M' is hydrogen, an alkali metal atom or a lower hydrocarbon group, one polar group being contained per 53,000 to 100,000 of the number-average molecular weight of the resin, and the vinyl chloride copolymer has one of the above-mentioned polar group, one polar group unit being contained per 10,000 to 100,000 of the number-average molecular weight of the copolymer. The recording layer contains a fatty acid ester lubricant having a low melting point, a carbon black having an average particle size of 90-150 .mu.m, and/or a .alpha.-alumina having a small average particle size. 
Fuji Photo Film Co., Ltd.
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Takahito Kazuko Yasuyuki Hiroo
Miyoshi Hanai Yamada Inaba