PROCESS FOR PRODUCING POLYMER-COATED FERROMAGNETIC PARTICLE, AND POLYMER-COATED FERROMAGNETIC PARTICLE

摘要

Polymer coated ferromagnetic particles could be obtained giving a solution to a problem of difficulty in dispersing ferromagnetic fine particles to a level of monodispersion because of their properties apt to form aggregates. Providing hydrophilic character to hydrophobic ferromagnetic particles obtained by adsorbing hydrophobizing agent to hydrophilic ferromagnetic particles, and dispersed using nonionic surface activating agent suppressing ionic strength increase of the particles. Monomer liquid was emulsified using nonionic surface activating agent and ionic surface activating agent. Mixing the dispersion liquid of ferromagnetic particles and the monomer emulsion were mixed and emulsion polymerization was conducted. Then well-dispersed homogeneous and stable polymer coated ferromagnetic particles showing good response to magnetic field were obtained.