SURFACE TREATED PIGMENT, ITS PRODUCTION AND USE THEREOF

摘要

PROBLEM TO BE SOLVED: To obtain a surface-treated pigment that is excellent in dispersion stability in an aqueous dispersion and is useful as a water-based ink jet recording liquid by setting the ratio of a specific surface area of nitrogen gas to that of-carbon dioxide gas. SOLUTION: The objective pigment has a specific surface area of nitrogen gas (Sn) of 60-200 m<2> /g and its ratio to a specific surface area of carbon dioxide (Sc) is 0.7-3.0 (Sn/Sc). This pigment is prepared by dispersing (A) a pigment, particularly a phthalocyanine pigment together with (B) a dispersing agent, particularly a surfactant with an HLB of 11-40 in an aqueous medium to allow the component B to be adsorbed on the surface of the component A. In a preferred embodiment, the component A is subjected to a salt-milling treatment before the dispersion.