Patent ID: 6599356
Filing Date: 2003-07-29
Classification: C01P,C09B,C09C,C09D

Abstract:
A method for manufacturing a pigment dispersed liquid, comprising the steps of:(A) introducing a hydrophilic dispersibility-imparting group directly and/or via another atomic group to the surface of pigment particles; (B) dispersing the pigment particles obtained in Step A in an aqueous medium to obtain a dispersed liquid; and (C) conducting a refining treatment of the dispersed liquid comprising (i) subjecting the dispersed liquid to ultra filtration in which an ultrafiltration film is used to separate the dispersed liquid into the pigment dispersed liquid that does not permeate through the ultrafiltration film and a filtrated liquid comprising impurities that permeate through the ultrafiltration film and a filtrated liquid comprising impurities that permeate through the ultrafiltration film, and (ii) recovering the pigment dispersed liquid, wherein the ultrafiltration film has a molecular cutoff size that results in the filtrated liquid having an absorbance which, at a maximum absorption wavelength, is 1.0 or less when a pigment concentration in the pigment dispersed liquid is converted to 10 wt. %.