| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a reversible thermochromic oil-based ink composition for writing instruments which does not cause deterioration of the capsule wall film due to erosion by a solvent, although the film wall thins and decreases in solvent resistance, even when a reversible thermochromic microcapsule pigment of a small average particle size is used in an oil-based ink composition as a colorant, and is excellent in temporal stability over a long period without inhibition of color change properties.SOLUTION: A reversible thermochromic oil-based ink composition for writing instruments includes a resin-coated pigment formed by coating, with a thermoplastic resin, a reversible thermochromic microcapsule containing a reversible thermochromic composition which comprises (A) an electron-donating coloring organic compound, (B) an electron-accepting compound and (C) a reaction medium determining the causing temperature for the coloring reaction of (A) with (B) and an organic solvent, and the solubility of the thermoplastic resin in the organic solvent is 0.2 or smaller. A writing instrument containing the oil-based ink composition is also provided.</p> |
