| 摘要 |
PURPOSE:To provide lightweight/mass-producible/low manufacturing cost magnetic particles by forming cavity parts inside of resin particles in the magnetic particles formed by dispersing magnetic powder in the resin particles. CONSTITUTION:Magnetic particles are formed by dispersing magnetic powder in resin particles, and cavity parts are formed inside of the magnetic particles, and apparent density is 0.9-2.0g/cc. Such magnetic particles can be obtained by carrying out suspension polymerization on a constituent containing polymeric monomer, the magnetic powder and an azo type polymerization initiator. The cavity parts are formed inside of the particles by sealing cracked gas of the azo type polymerization initiator in the particles when the suspension polymerization is carried out. |
