| 摘要 |
PURPOSE:To obtain magnetic iron oxide particles having large bulk density and excellent milling characteristics by adding acetic acid of 0.1-2.0wt% to Fe2O3 to magnetic iron oxide particles and treating the surfaces of the particles with acetic acid. CONSTITUTION:Acicular crystal goethite particles are formed by oxidizing a reaction aqueous solution of a ferrous salt aqueous solution and alkali by air. Acicular crystal maghemite particle powder is obtained by heating-dehydrating, reducing and re-oxidizing said particles. The 1,000g particle powder and 5.7ml 0.1-2.0wt% acetic acid are charged into an edge runner, and compaction-ground for 60min. Acicular crystal maghemite particle powder on which obtained acetic acid adheres is used, a mixed solvent consisting of a proper amount of a dispersant, a vinyl-chloride vinyl-acetate copolymer resin, a thermoplastic polyurethane resin, toluene, methyl ethyl ketone and methyl isobutyl ketone is compounded at a predetermined composition, and mixed and dispersed, thus manufacturing magnetic paints. |
