| 摘要 |
<p>PURPOSE:To provide a color-dying marking pen ink capable of forming a holograph to be decolored with the passage of an arbitrary desired period within a prescribed range independently of the acidity of the subject surface. CONSTITUTION:A compound selected from cyclodextrin and its derivatives is contained in an aqueous colored solution in which the color of a phthalein- based pH indicator is developed with a basic substance.</p> |
