| 摘要 |
PROBLEM TO BE SOLVED: To improve resistance to water and bleeding, and, especially for an ink containing an insoluble colorant, to maintain or improve the stability and reliability of a dispersion while improving resistance to water and bleeding, by incorporating, in an aqueous carrier medium, a colorant insoluble in the medium, a branched polymer dispersant and an emulsion polymer additive. SOLUTION: (a) An aqueous carriers medium, which is a mixture of water and a polyhydric alcohol such as ethylene glycol, has a water content of 30 to 95% and accounts for 60 to 99.8wt.% of the total ink composition. (b) A colorant is a dye or a pigment which is insoluble in component (a). A pigment and a particulate metal or metal oxide having a particle diameter of 0.005 to 5 microns are used. Component (b) accounts for 0.05 to 8% of the total ink composition. (C) A branched polymer dispersant has a main chain containing both a hydrophilic and a hydrophobic portions and macromonomer side chains, and accounts for 0.1 to 8wt.% of the total ink composition. (d) The amount of an emulsion polymer additive is 0.1 to 20wt.% based on the total solids of this composition. This composition is prepared by compounding components (a), (b), (c) and (d) in respective amounts as mentioned above. |
