| 摘要 |
PURPOSE:To imoprove the dispersibility and durability of magnetic powder by adding polyurethane elastomer which uses a vinyl chloride copolymer and cellulosic resin, and TDI as an isocyanate component to a binder for a magnetic layer. CONSTITUTION:A binder for a magnetic layer contains polyurethane elastomer which uses a vinyl chloride copolymer and cellulosic resin, and tolylenediisocyanate (TDI) as an isocyanate component and has >=10,000 mean molecular weight. In this case, said polyurethane elastomer is obtained through the condensation polymerization of a polyol component and TDI as the isocyanate component in the usual way, and as the polyol component, a polyester polyol component of polyhydric alcohol such as 1.4 butanediol, etc., and polybasic acid such as adipic acid, various polyether polyol components, etc., are usable. |
