| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a water-color ink obtained by using a pigment as a coloring matter, and having good discharge stability by adding a specific acetylene glycol compound as a surfactant to water, the pigment as a coloring matter and an organic solvent. SOLUTION: This water-color ink comprises (A) water, (B) a pigment as a coloring matter (e.g. carbon black), (C) an organic solvent (e.g. ethylene glycol) and (D) a surfactant of the formula. The compound of the formula (m and n are each an integer of >=1, with the proviso that m+n is 1-30) is preferable as the component D. Preferably, 0.5-25 wt.% component B, 5-50 wt.% component C and 0.01-1 wt.% component D are added to the aqueous ink composition. The objective product preferably has 20-50 dyne/cm static surface tension, pH 6.5-10 and 1-10 cps viscosity, and preferably providing <=10 deg. contact angle at 30 s after the impact of the ink, and <=30 deg. contact angle at 0.1 s after the impact of the ink.</p> |
