| 摘要 |
The ink composition is composed of 0.2-1.5g phthalein indicator, 1-5cc dimethylformamide (DMF), 20-40cc alcohol, 0.5-1g sodium hydroxide, 2-5cc propyl gallate, and 40-70cc water. Among the composition, sodium hydroxide, propyl gallateand and water are used to regenerate the erased letters soon after writing, and the indicator is used to show the color change during the perishing of letters. The ink composion can be used as printing ink composition and in various writing pens. |
