| 摘要 |
PURPOSE:To obtain a magnetic material which has excellent dispersibility and magnetic characteristics and gives a magnetic film having excellent wear resistance, etc., by immersing a powdered magnetic material in an aq. soln. of a specified phosphate ester, filtering the material and drying it. CONSTITUTION:An aq. soln. of one member selected from phosphate monoester of formulaI, phosphate diester of formula II (wherein R is 4-24C alkyl, alkenyl, alkylphenyl; n is 0, 1-30; m is 1-30) and derivatives thereof, is prepd. A powdered magnetic material such as gamma-Fe2O3 or magnetite is immersed in the aq. soln., filtered and dried to obtain the desired magnetic material. The compds. of formulasI, II can be prepd. by addition-polymerizing propylene oxide or ethylene oxide and propylene oxide with a 4-24C alcohol or an alkylphenol and then seterifying the obtained addition polymer with phosphoric acid. |
