| 摘要 |
PROBLEM TO BE SOLVED: To provide a water-based ink composition for ballpoint pens, which includes a reversible thermochromic composition-encapsulating microcapsule pigment as a colorant, is excellent in drought resistance, can form lastingly excellent handwriting, and has reversible thermochromism rich in practicality, and to provide a ballpoint pen refill using the water-based ink composition for ballpoint pens, and the ballpoint pen.SOLUTION: The water-based ink composition 6 for ballpoint pens comprises, at the least, a pigment, water, a polysaccharide thickener and a collagen peptide having ≥2,000 average molecular weight. The ballpoint pen refill 1 using the water-based ink composition for ballpoint pens and the ballpoint pen are also provided. |
