Document Type and Number:
Japanese Patent JPH0132267
Kind Code:
B2
Abstract:
PURPOSE:To obtain a magnetic ink having a high magnetization intensity in a low magnetic field and in a black solution, by adding surfactant to an aqueous suspension of Mn-Fe ferrite powder, acidifying the resultant mixture, and dispersing acidified mixture in an oil. CONSTITUTION:A surfactant, e.g. sodium oleate, consisting of a unsaturated fatty acid (salt) is added to an aqueous suspension of fine Me-Fe ferrite powder having the composition of 35-60mol% Fe2O3, 1-60mol% FeO and 1-64mol% MnO prepared by the wet method. An acid is then added thereto to give an acidic aqueous solution having a pH of 7-5. The resultant flocculate is then filtered and washed with water or a polar solvent, dehydrate and then dispersed in a solvent of low polarity, e.g. kerosene.
Inventors:
SHIMOIIZAKA JUNZO
Application Number:
JP4067481A
Publication Date:
June 30, 1989
Filing Date:
March 20, 1981
Export Citation:
Assignee:
SHIMOIIZAKA JUNZO
International Classes:
G11B5/62; C09D5/23; C09D7/12; C09D9/04; C09D11/00; H01F1/00; H01F1/34
Next Patent: JPH0132268