| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a water-based reversibly thermochromic ink composition which, even when left standing in an environment lower than 0°C where the ink freezes or even when put to practical use in the case in which the ink changes its color in a freezing temperature region and is encased, does not impair ink flowability in writing and therefore exhibits such writing performance as not to cause blurred writing and color lightening, and to provide a direct liquid-type writing utensil using the above ink composition. <P>SOLUTION: The water-based reversibly thermochromic ink composition is such as to be contained in a writing utensil with an ink contained directly in its cartridge. This ink composition comprises (i) an electron-donating colorable organic compound, (ii) an elctron-accepting compound and (iii) a vehicle comprising water, a polymeric flocculating agent and a reversibly thermochromic microencapsulated pigment including a reversibly thermochromic composition comprising a reactive medium that determines the temperature causing the coloring reaction between the components(i) and (ii). This ink composition is 35-45 mN/m in surface tension. The direct liquid-type writing utensil using the above ink composition is also provided. <P>COPYRIGHT: (C)2008,JPO&INPIT |
