| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a color changeable black ink composition which can form a deep writing on the writing surface, can be decolored by coating a color changing fluid on the writing, and excels in safety and utility, color changeable writing utensils having the composition built-in, and a set of writing utensils composed of the color changeable writing utensils and a color changing applicator housing a color changing fluid. <P>SOLUTION: The color changeable black ink is composed of at least water, C. I. Basic Green 1 as a decoloring dye by a reducing agent, and a decoloring dye by the reducing agent which is in a hue of the complementary color pair with the above C. I. Basic Green 1, and has a pH of 6 or less, and the color changeable writing utensils in the form of marking pens have the color changeable black ink composition built-in. The set of writing utensils is composed of the color changeable writing utensils and a color changing applicator housing a color changing fluid. <P>COPYRIGHT: (C)2007,JPO&INPIT |
