Magnetic recording medium in the form of a floppy disc having a magnetic layer with a specified surface feature

摘要

A novel magnetic disc and process for the preparation thereof is disclosed, comprising a nonmagnetic support having thereon a magnetic layer comprising ferromagnetic metal particles and a binder resin containing at least a vinyl chloride copolymer, wherein the crystallite size of the ferromagnetic metal particles as determined by X-ray diffraction method is 300 (Aangstroem) or less, and the ratio (alpha) at the surface of the magnetic layer of the integrated intensity of the Cl-2P spectrum as determined by X-ray photoelectron spectroscopy to that of the Fe-2P(3/2) spectrum is in the range of from 0.50 to 0.90. In a preferred embodiment, the vinyl chloride copolymer contains at least one polar group selected from the group consisting of -SO3M, -OSO3M, -PO3M2, and -CO2M wherein M represents hydrogen, an alkali metal or ammonium and at least one epoxy ring in the copolymer molecule.