| 摘要 |
PROBLEM TO BE SOLVED: To obtain an ink composition not suffering from the agglomeration or precipitation of the pigment as the colorant upon a long-term or temperature change and having excellent pigment dispersion stability by mixing a pigment with water or a water-soluble compound. SOLUTION: The water-soluble compound used is a combination of a compound of formula I and/or a salt thereof with a polyacrylic acid having a viscosity of 100 cP or below at 25 in a 5 wt.% aqueous solution and/or a salt thereof. In the formula, R1 is H or CH3; R2 is a 10-30C alkyl; M is H, Na, Li, amine, or ammonium; structural units of formula II amount to 40-98 wt.%, and structural units of formula III amount to 2-50 wt.%. Desirably, a compound of formula I and/or a salt thereof constitute 10-99 wt.% of the entire weight of the water-soluble compound. The dispersion medium used contains water as an essential component and a water-soluble organic solvent as an optional component. Desirably, the viscosity of the ink is set at 50-2,000 cP. |
