REVERSIBLY THERMOCHROMIC AQUEOUS INK COMPOSITION FOR USE IN BALLPOINT PEN, AND BALLPOINT PEN REFILL AND BALLPOINT PEN EACH USING SAME

摘要

Disclosed are a reversibly thermochromic aqueous ink composition for use in a ballpoint pen, which comprises a microcapsule pigment obtained by enclosing a reversibly thermochromic composition as a coloring agent, and which has excellent drying resistance, can permanently form good handwriting, and is very suitable for practical use, and a ballpoint pen refill and a ballpoint pen each using same. More specifically disclosed are a reversibly thermochromic aqueous ink composition for use in a ballpoint pen, comprising a microcapsule pigment obtained by enclosing a reversibly thermochromic composition containing (i) an electron-donating color-forming organic compound, (ii) an electron-accepting compound, and (iii) a reaction medium which controls a color-forming reaction between the compound (i) and the compound (ii) in microcapsules, water, a polysaccharide, and smectite, and a ballpoint pen refill and a ballpoint pen each using same.