To provide an aqueous pigment dispersion in which a pigment is finely dispersed, and an agglomerated pigment precipitated in a head-cleaning operation can be made resoluble easily when applying to an inkjet printer, and by which an ink discharge stability is retained and the ink having excellent storage stability can be provided.
The aqueous pigment dispersion for inkjet ink includes the pigment, a pigment derivative and a polymeric dispersant. In the pigment derivative, one or more acidic groups in the molecule thereof are chemically modified. The polymeric dispersant is a diblock polymer comprising a hydrophilic block and a hydrophobic block, and PDI (polydispersivity) of the diblock polymer is ≤1.5. The dispersant contains at least benzyl methacrylate or cyclohexyl methacrylate as a monomer composing the hydrophobic block. The number-average molecular weight of the hydrophobic block is 500 to 50,000.
WATANABE MASARU
SHIMANAKA HIROYUKI
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