| 摘要 |
PURPOSE:To improve the adhesion between a polyester film and an under-coat layer, to improve the adhesion between a magnetic layer and the undercoat layer, and to improve the adhesion between the magnetic layer and a base body by incorporating a vinyl chloride copolymer having <=200 polymerization degree and contg. >=2wt% OH group into the undercoat layer. CONSTITUTION:A vinyl chloride-vinyl acetate-vinyl alcohol copolymer, a vinyl chloride-vinyl propionate-vinyl alcohol copolymer, a vinyl chloride-acrylic ester copolymer, and a vinyl chloride-vinylidene chloride copolymer each having <=200 polymerization degree and contg. >=2wt% OH group are examplified as the vinyl chloride copolymer having <=200 polymerization degree and contg. >=2wt% OH group. A single compd. among the compds. or a mixture of >=2 kinds of the compds. are used. The vinyl chloride copolymers can be used jointly with a curing agent such as an isocyanate compd., an epoxy compd., and an ethyleneimine compd. When the curing agent is jointly used, a tough undercoat layer is formed, and the adhesion with a magnetic layer is improved.
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