Production method for aqueous pigment dispersion

Abstract

The present invention relates to [1] a process for producing a water-based pigment dispersion, including step 1 of subjecting an ionic group-containing monomer (a) and a hydrophobic monomer (b) to polymerization reaction using an ionic group-containing polymerization initiator (x) and an ionic group-containing chain transfer agent (y) to obtain an ionic group-containing polymer A, step 2 of mixing and dispersing the obtained polymer A and a pigment in an aqueous medium to obtain a pigment water dispersion, and step 3 of subjecting the polymer A in the obtained pigment water dispersion to crosslinking reaction with a polyfunctional compound to obtain the water-based pigment dispersion, and [2] a process for producing a water-based ink, including, in addition to the aforementioned steps 1 to 3, step 4 of mixing the obtained water-based pigment dispersion with an organic solvent to obtain the water-based ink. The resulting water-based pigment dispersion and water-based ink can exhibit excellent redispersibility and high flowability by which it is possible to suppress clogging of ink ejection nozzles owing to solidification of a pigment or a polymer in the ink ejection nozzles.

Dependencies are inferred from the claim text.