Oil-based ball-point pen refill, oil-based ball-point pen, and oil-based ball-point pen ink composition

摘要

An oil-based ball-point pen refill includes a ball-point pen tip in which a ball is held, in which the ball-point pen tip is mounted on a leading end of an ink housing cylinder, an ink composition including a coloring agent consisting of a dye, an organic solvent, and polyvinyl butyral resin is housed in the ink housing cylinder, the arithmetic mean roughness of a surface of the ball is 0.1 to 15 nm, the content of the polyvinyl butyral resin is 50 mass % or more based on the total mass of the whole resin, and an ink viscosity is 5000 to 50000 mPa·s. In an oil-based ball-point pen, the refill is disposed in a barrel cylinder. An oil-based ball-point pen ink composition including a specific salt-forming dye, polyvinyl butyral resin, and an aromatic alcohol can be utilized in the refill.