PLASTIC MAGNETIC COMPOSITION

摘要

PURPOSE:To provide the titled compsn. having excellent physical properties and moldability, by a method wherein a mixt. of an elastomer such as butyl rubber and an ethylene-vinyl acetate copolymer is heated in the presence of an org. peroxide to produce a partially cured thermoplastic polymer compsn. and then a magnetic powder is dispersed in the partially cured thermoplastic polymer compsn. CONSTITUTION:A mixt. of at least one elastomer (a) selected from a butyl rubber and an ethylene-propylene copolymer rubber and an ethylene-vinyl acetate copolymer (b) is heated with mixing in the presence of an org. peroxide (e.g. benzoyl peroxide) to partially cure the mixt. to such an extent that the reaction product does not lose good melt frow characteristics. Then a magnetic powder is dispersed in the resulting thermoplastic polymer compsn. having good melt flow characteristics and elastic properties to obtain the titled magnet comspn. The compsn. is subjected to orientation in the magnetic field in a molding stage to obtain a permanent magnet.