摘要 |
PROBLEM TO BE SOLVED: To provide an oil-based ink composition for a ball-point pen having suppressed defect of dropping the ink in a mass by controlling the inner cohesive force of the ink. SOLUTION: The oil-based ink composition for ball-point pen at least contains a coloring material, a resin and 0.01-1.5 wt.% high-polymer polybutyl vinylal having a polymerization degree of≥900 (calculated molecular weight:≥60,000) and further contains a solvent selected from an alcohol, a polyhydric alcohol and a glycol ether having a vapor pressure of≥0.001 mmHg at 25°C as a main solvent accounting for≥50% of the total solvent. COPYRIGHT: (C)2004,JPO |