| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a water-based pigment dispersion having excellent water- dispersibility and dispersion stability with time, and a method for producing the dispersion, and further to provide a method for producing a water-based pigment dispersion having excellent light resistance, water resistance, hue and print density after the printing, and a reproduction range of the color range when being printed on regular paper, further having good jetting stability at a nozzle, and usable for a water-based recording liquid for inkjet, in the recording liquid for the inkjet by using the water-based pigment dispersion. SOLUTION: This method for producing the water-based pigment dispersion is characterized in that the method comprises a step for sulfonating a pigment to introduce one or more sulfo groups into the molecule, a step for removing pigment derivatives having two or more sulfo groups from the reaction product to concentrate the sulfo group-containing organic pigment derivative having only one sulfo group, and a step for dispersing a pigment having the molecular structure of the pigment akin to the sulfo group-containing pigment derivative in the presence of the sulfo group-containing pigment derivative obtained at the above step, in water.</p> |
