FINE PARTICLE RED IRON OXIDE PIGMENT, ITS PRODUCTION, COATING MATERIAL USING THE SAME AND RESIN COMPOSITION

摘要

PROBLEM TO BE SOLVED: To obtain a fine particle red iron oxide pigment excellent in transparency by suppressing the geometric standard deviations of major axis size and minor axis size of fine hematite particles below a specified value and specifying the average major axis size of the particles. SOLUTION: The fine particle red iron oxide pigment comprises fine hematite particles having a geometric standard deviation of major axis size of <=1.5, a geometric standard deviation of minor axis size of <=1.3 and 0.005-0.1μm average major axis size. Fine particulate goethite powder having a geometric standard deviation of major axis size of <=1.8, a geometric standard deviation of minor axis size of <=1.7, 0.005-0.1μm average major axis size and 0.0025-0.05μm average minor axis size is heated at 100-200 deg.C for 5-60 min to absorb hyperfine goethite particles into fine goethite particles. The powder is then dehydrated by heating at 250-500 deg.C to obtain the fine hematite particles. Preferably, the average major to minor axis size ratio of the red iron oxide pigment is 2-20 and the BET specific surface area is appropriately 40-250 mm2/g.