| 摘要 |
<p>PURPOSE:To prevent the wear of a ball seat at a ball-point pen tip and realize a long-term dispersion stability of a carbon black pigment bt using as a coloring agent a neutralized acidic carbon black having a group of an acidity above a specified value on its surface. CONSTITUTION:A prescribed amount of a carbon black pigment having an acid value of at least 0.2g of sodium hydroxide for 10g of carbon black is mixed with an aqueous solution containing an alkali metal hydroxide in an amount sufficient to neutralize the carbon black to give a paste. The paste is continuously milled or left to stand for a prescribed period of time after milling, thus completing neutralization in several hours or tens of hours after the mixing. The neutralized paste is then dispersed in an aqueous vehicle to prepare a water-base black ball-point ink.</p> |
