| 摘要 |
PURPOSE:To obtain a diazo fixation type thermal recording medium having excellent chemical resistance, favorable raw preservability and high sensitivity, by providing on a photosensitive thermal recording layer a protective layer comprising a highly saponified polyvinyl alcohol having a saponification degree of at least a specified percent and a nonionic surfactant having an HLB of not less than a specified value. CONSTITUTION:A nonionic surfactant having a hydrophilic-lipophilic balance (HLB) of not less than 10 is incorporated particularly in an amount of 3-0.1wt% based on the amount of a highly saponified polyvinyl alcohol having a saponification degree of not less than 95%. With the nonionic surfactant used, a uniform coated layer can be obtained, and even when a solid black image is formed, the density of the image is uniform, resolution is excellent, and an extremely favorable image can be obtained. If a so-called partially saponified polyvinyl alcohol having a saponification degree of less than 95% is used in a protective layer, raw preservability is degraded although chemical resistance is surely enhanced by the protective layer. |
