| abstract |
A water-based ink composition for ballpoint pen, which comprises at least a colorant, water, a shear-thinning tackifier and a thickening inhibitor, wherein a ratio (x) of a viscosity after evaporation of 40 wt % of water from the total ink amount to an initial ink viscosity (as measured by EMD viscometer at 1 rpm and 20° C.) is 2 or less; and a ballpoint pen comprising the same. |