| 摘要 |
PURPOSE:To provide a heat sensitive recording material which is superior in keeping properties such as whiteness, heat resistance, moisture resistance, chemical resistance and plasticizer resistance and has favorable image keeping properties, by a method wherein the heat sensitive recording material is allowed to contain at least one kind of a leuco indigo derivative represented by a specific formula as a dye precursor. CONSTITUTION:In a heat sensitive recording material wherein a heat sensitive recording layer containing a colorless or light-colored dye precursor and a basic compound which is capable of making color development in contact with the dye precursor is provided, the heat sensitive recording material is made to contain at least one kind of leuco indigo derivatives represented by formula I as the dye precursor. In the formula I, R, R' are respectively independently 1-10C primary alkyl group or 3-10C secondary alkyl group or a halogen atom or an aryl group which may be replaced with 1-6C alkyl group or 1-6C alkyl group. X, Y show respectively independently -NR9-, or -S-, the X, Y may be bonded in a form of formula II. |
