Process for the preparation of an organic pigment dispersion

摘要

An organic pigment dispersion in a non-aqueous medium is prepared directly from an aqueous slurry containing 0.1-20% by weight of the pigment by mixing the aqueous slurry with the non-aqueous medium under vigorous agitation and subsequently isolating the organic pigment dispersion from the residual aqueous phase. A substantial part of water in the resulting pigment dispersion can be removed by passing the organic pigment dispersion in the non-aqueous medium over a series of surfaces, the surface material thereof having different affinity for water and the non-aqueous medium, respectively, and then removing water and pigment dispersion in the non-aqueous medium, respectively, from respective surfaces.