| 摘要 |
PURPOSE:To produce a magnetic fluid in high yield, excellent in dispersion stability and having a high saturation magnetization value. CONSTITUTION:To a suspension of coprecipitated ferrite fine particles is added polybutenylsuccinimide tetraethylenepentamine solution in a hydrocarbon solvent having higher boiling point than that of water and making no azeotrope with water to make an emulsion under agitation by heating. Then, water is distilled off by heating under agitation to only leave a solution of the hydrocarbon solvent, which is treated by heat under nitrogen flow at >=ca. 180 deg.C. A coagulating solvent us added and the solution is preferably treated to disperse in an aromatic hydrocarbon to obtain polybutenylsuccinimide tetraethylenepentamine adsorbed ferrite fine particles, which is dispersed in a base oil under a low steam pressure to obtain the magnetic fluid. |
