| 摘要 |
PURPOSE:To provide the titled material having a remarkably high sensitivity, free of fading of images or the like and having a high ground brightness, wherein two special bisphenol derivatives are used in combination as a color developer, and other specified bisphenol derivative is incorporated in an undercoat layer. CONSTITUTION:First, the undercoat layer is provided on a base by using a bisphenol derivative of formula I, wherein each of groups X is halogen, the groups X on the left and right benzene rings are located at symmetrical positions with respect to -SO2-, and (p) is an integer of 0-2, e.g., bis(4-hydroxy) sulfone, together with a filler and a binder. Then, a thermal color forming layer comprising a color developer consisting of bisphenol derivatives of formula II, wherein (n) is 1 or 2, and formula III, wherein each of groups X is halogen and the groups X on the left and right benzene rings are located at symmetrical positions with respect to -C(CH3)2-, and a leuco dye as main constituents is provided on the undercoat layer to obtain the objective material. The compound of formula III is, for example, 2,2'-bis(4-hydroquione-3,5-dibromophenyl)propane. |
