| 摘要 |
PURPOSE:To prevent generation of drop-out and to obtain excellent running durability by incorporating a binder contg. a specific vinyl chloride copolymer and polyurethane resin and alpha-alumina particles as a polishing agent into a magnetic layer on a nonmagnetic base. CONSTITUTION:The vinyl chloride copolymer or vinyl chloride/vinyl acetate copolymer and the polyurethane resin or polyester resin having at least one functional group among a -COOM group (M is H, alkali metal atom or hydrocarbon), -PO(OM')2 group (M is H, alkali metal, alkaline earth metal or hydrocarbon), -SO3M group, -OSO3M group (M is the same as above) and -CH2S(=O)M'' group (M'' is hydrocarbon), etc. are incorporated into the magnetic layer on the nonmagnetic base as the binder and the alpha-alumina particles are incorporated therein as the polishing agent. Such alpha-alumina- and functional group-contg. polyurethane vinyl chloride acetate system has a high Young's modulus and since the three-dimensional structure of the coated film binder develops, the wear with a head is decreased, the increase in running tension is low and an increase in YS/ND0 is good. The durability is thus enhanced.
|
