MAGNETIC FLUID

摘要

A magnetic fluid comprises a mixture of a magnetic dispersion prepared by dispersing magnetic fine particles into an organic dispersion medium by the aid of a surfactant and a colorant prepared by pretreating a coloring material with a solubilizing treating agent or a dispersibilizing treating agent comprising a hydrophobic group and a functional group adsorbable or linkable to the coloring material. The hydrophobic group comprises alkyl, cycloalkyl, alkenyl or aralkyl and the functional group comprises carboxyl, carboxylic bromide, sulfonic acid, sulfonyl chloride, primary amino, secondary amino or phenyl.