| 摘要 |
PROBLEM TO BE SOLVED: To provide an inkjet ink having improved optical density and chroma saturation of images, especially improved brightness and clarity (DOI).SOLUTION: There is provided an aqueous pigment inkjet ink containing an urea terminal polyurethane ink additive and an aqueous pigment dispersion in an aqueous vehicle, the aqueous pigment dispersion contains a polymeric ionic dispersion and a pigment, (a) the polymeric ionic dispersion is physically adsorbed to the pigment, (b) the polymeric ionic dispersion disperses the pigment in the aqueous vehicle stably, (c) the dispersion has an average particle diameter of less than 300 nm and the weight percentage of an urea terminal polyurethane part of the polyurethane determined by dividing mass of an amine chain terminator by the sum of other polyurethane components containing the chain terminator is 2 wt.% to 6.8 wt.% based on the total weight of the urethane resin, and the urethane terminal polyurethane is crosslinked in the inkjet ink of the amount of over 0.5 wt.% to 30 wt.% based on the total weight of the aqueous ink, and the amount of crosslink in the crosslinked polyurethane is over 1% and less than 50% in a measurement by a THF insoluble fraction test. |
