| 摘要 |
PROBLEM TO BE SOLVED: To provide a water-based ink composition for a ballpoint pen, with which fine writing quality and handwriting are obtained and which exhibits stable writing performance for a long period of time, by imparting high water resistance thereto, even when a copolymer exhibiting excellent pigment dispersion stability when added to a water-based ink using a shear-viscosity reducing agent is used, and to provide a ballpoint pen incorporating the same.SOLUTION: A water-based ink composition for a ballpoint pen contains a pigment, water, a shear-viscosity reducing agent, a copolymer of N-vinylpyrrolidone or a derivative thereof and an alkene compound, and a glycol ether of which the main skeleton is a glycol having 4 or more carbon atoms. The ballpoint pen incorporates the water-based ink composition for the ballpoint pen. |
