| abstract |
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, -SO3M, -OSO3M 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, 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. |