Showa Shell Sekiyu K.k.

Nikkato Corporation

Shougo Kodama

Masayoshi Nakamura

Teruaki Ohki

Hiroyoshi Kawase

A method for dispersing a pigment is disclosed, wherein the pigment is dispersed in a medium solution by using sintered zirconia beads having an average particle diameter of 40 to 192 .mu.m, a density of 5.9 g/cm.sup.3 or more, and a sphericity of 1.07 or smaller. The method is particularly useful for providing an excellent coating gloss when the medium solution is a binder for forming a paint or a coating composition or a binder for forming an ink composition.

Method for dispersing pigments

A method for producing ultra fine particles is disclosed, wherein the method includes wet grinding particles with a media agitation mill, wherein ceramic particles having an average diameter of about 300 .mu.m or smaller are used as grinding media in the media agitation mill. Desirably, the media has an average particle diameter standard deviation of 15 or smaller, a sphericity of 1.07 or smaller, and a density of 6.0 g/cm.sup.3 or more.

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Tokyo, Japan

Shougo Kodama