| 摘要 |
PURPOSE:To improve the light and water resistance of a recording paper, by adding a specific fluoran derivative as an electron-donating color former to a substrate. CONSTITUTION:A fluoran derivative of the formula (where R<1> and R<2> are each a C1-C8 alkyl or alkenyl and R<3> is a C1-C8 cycloalkyl) as a color former capable of giving black color by an acid substance is added to a substrate. In the preparation of a heat-sensitive recording paper, said color former is dissolved in a solvent (e.g., dichlorobenzene, propylnaphthalene), and an acid substance (e.g., clays such as acid clay, attapulgite) is used. The specific fluoran derivatives are prepared by dehydrocondensation of phenolic derivatives of formulas II (where R<1> and R<2> are the same as above) and III (R<2> is the same as above and R is a C1-C4 alkyl). |
