A water-based ink for inkjet printing comprising a water dispersion of
vinyl polymer particles prepared by containing a
pigment in a
vinyl polymer prepared by copolymerizing a
monomer mixture comprising (a) a salt-forming group-containing
monomer, (b) a macromer, and (c) a
monomer copolymerizable with the salt-forming group-containing monomer and the macromer; and a process for preparing a water-based ink for
inkjet printing comprising a water dispersion of
vinyl polymer particles prepared by containing a
pigment in a vinyl
polymer, comprising dissolving in an
organic solvent a vinyl
polymer prepared by copolymerizing a monomer mixture comprising (a) a salt-forming group-containing monomer, (b) a macromer, and (c) a monomer copolymerizable with the salt-forming group-containing monomer and the macromer; adding a
pigment to the resulting solution; pre-kneading the mixture; thereafter adding a neutralizing agent and water and kneading the mixture, to give an oil-in-water dispersion; and distilling off the
organic solvent from the resulting kneaded product.