| 摘要 |
PURPOSE:To impart sufficient dynamic developed color density and improve the stability of a developed color image by providing a thermal color forming layer based on a specific fluorane leuco dye and an org. developer and compounded with a specific sensitizer on a support. CONSTITUTION:Specified amounts of a fluorane leuco dye represented by formula I, an org. developer and at least one of o-xylylene-bis-(phenyl ether) and 4-(m-methylphenoxymethyl)biphenyl being sensitizers are finely ground by a grinder such as a ball mill and a binder is added to the ground mixture to prepare a coating solutin for a thermal color forming layer. This coating solution is applied to a support such as paper, synthetic paper or a plastic film and dried to form the thermal color forming layer to produce a thermal recording sheet. As a concrete example of the org. developer, there are bisphenol A, 4-hydroxybenzoate and the like. An undercoat layer containing an org. filler can be also provided under the thermal color forming layer for the purpose of enhancing preservability and sensitivity. |
