| 摘要 |
PURPOSE:To obtain a recording material having favorable color forming properties, raw preservability and stability of developed color images, by using a fluoran compound having an isopropyl group at 1-position as an electron-donative colorless dye. CONSTITUTION:A fluoran derivative having an isopropyl group at 1-position is used in a recording material utilizing a color forming reaction upon contact of an electron- donative colorless dye with an electron-acceptive compound. The dye rapidly forms a color upon making contact with the electron-acceptive substance. The coloring matter thus developed into color is substantially free of discoloration or fading even when being irradiated with light, heated or moistened for a long time, which is advantageous for long-time preservation of a record. The color former has excellent stability, so that it is free of changes in properties or coloring even after long-time preservation, and retains a sufficient color forming capability. The electron-acceptive compound may be an inorganic or organic Lewis acid or Bronsted acid. When the recording material is used as a thermal recording paper, the colorless dye and the electron- acceptive compound are used in the state of being dispersed through grinding to a particle diameter of not more than 10mum, preferably, not more than 3mum in a dispersant. |
