| 摘要 |
<p>To obtain inks for oily ballpoint pens and oily ballpoint pens which are excellent in the clearness of the written trace and drying properties thereof and can give favorable written trace and writing performance, ink compositions are prepared from an oil-soluble dye, water, an organic solvent in which water is soluble and which has a vapor pressure at 20 °C of 0.5 mmHg or more and another organic solvent in which the above-described organic solvent having a vapor pressure at 20°C of 0.5 mmHg or more is soluble and which has a vapor pressure at 20 °C of 0.1 mmHg or less. The sum of these three components amounts to 20 to 75% by mass based on the whole ink composition. The content of water ranges from 3.0 to 15.0% by mass based on the whole ink composition. The ink viscosity at 20 °C ranges from 100 to 5,000 mPa.s.</p> |
