PURPOSE: To obtain a magnetic fluid excellent in both dissolvability and dispersibility, by incorporating a surfactant constituted by phosphoric ester of polyoxyalkylenemonoether in a mixture of solvent and ferromagnetic powder coated with unsaturated fatty acid.
CONSTITUTION: The objective magnetic fluid can be obtained by incorporating a mixture of (A) ferromagnetic particles (pref. of oxide with spinel structure) coated with unsaturated fatty acid such as oleic acid, linoleic acid and (B) a solvent (pref. of ester, polyphenyl oil) with (C) a surfactant consisting of phosphoric ester of polyoxyalkylenemonoether of formula [R is aliphatic or aromatic, X is polyoxyalkylene chain (with such a proviso as to bond to P at O-side); Y is H, or cation; l is 1W3, etc.].
HARADA HIROSHI
OKUYA KATSUNOBU
Next Patent: JPS6058498