| 摘要 |
PROBLEM TO BE SOLVED: To provide a water-based ink composition for ballpoint pens which exhibits excellent sag-proof performance without harming dry-up-proof performance, and to provide a ballpoint pen filled therewith. SOLUTION: The ink composition comprises at least water, a coloring agent, a water-soluble organic solvent and a carboxymethylcellulose sodium salt. The carboxymethylcellulose sodium salt has viscosity of 1% aqueous solution thereof by a Brookfield viscometer (at 20°C and 30 rpm) of 20-1,000 mPa×s and a degree of substitution (a degree of etherification) by a carboxymethyl group of 0.7-1.3. The ballpoint pen is filled with the ink composition. COPYRIGHT: (C)2005,JPO&NCIPI |
