PURPOSE: To improve electromagnetic, heat resistant and durability characteristics by incorporating respective polymers of a vinyl monomer contg. a sulfobetaine group and ≥1 kinds among many vinyl monomers contg. SO3M1 groups or hydroxyl groups, etc., and vinyl chloride monomer at respectively specific weight % into the binder resin compsn.
CONSTITUTION: A copolymer A of the vinyl monomer contg. sulfobetaine group, such as N-(3-sulfopropyl)-N-methacrylamide propyl-N and vinyl chloride monomer is obtd. A copolymer B is obtd. from ≥1 kinds among vinyl monomer group contg. SO3M1 group, PO2(OM2) group or hydroxyl group, etc., and vinyl chloride monomer. These copolymers A, B are incorporated respectively at ≤95wt.% ratios into the binder resin compsn., to obtain the binder resin compsn. C. The one surface of a base is provided with a magnetic layer consisting of magnetic powder and a compsn. C and the other surface is provided with a nonmagnetic layer consisting of the compsn. C to obtain the magnetic recording medium. As a result, the excellent affinity to magnetic powder is obtd. and the packing of the magnetic powder at a high density with high orientation is made possible. The electromagnetic characteristics, heat resistance, durability and wear resistance are thus improved.
KAKEI HIROSHI
KOYAMA HIROSHI
TOKUYAMA SEKISUI IND CORP