1977 年 26 巻 288 号 p. 819-822
Copper particles, glass beads and enamel frit-polymer compound powders were prepared by the air suspension coating method, the spray drying method and the liquid suspension coating method. Epoxy resin, methyl methacrylate resin and polystyrene were employed as polymers. The mean particle sizes of the compound powders prepared by the air suspension coating method and the liquid suspension coating method were about 100μm, while the size of the powder prepared by the spray drying method was about 10μm.
The compound powder was pressed into a disc and the corona-charging potentials of the powder layers were measured. The corona-charging properties of the compound powders depended on the kind of polymers and on the preparation method. The compound powders using epoxy resin generally showed high surface potentials and the decaying of the surface potential was slow. The surface potentials increased with an increase in polymer content for all compound powders. The compound powders prepared by the air suspension coating method and the spray drying method showed high surface potentials, while the surface potentials of the corona-charged powder layers decayed very rapidly for the compound powders prepared by the liquid suspension coating method. The complexing situations of core materials and polymers are assumed to affect the corona-charging properties of compound powders.