| 摘要 |
PURPOSE:To restrain scumming and enhance plate wear characteristics, by incorporating at least one resin comprising at least one functional group which has at least two hydroxyl groups located sterically close to each other in the state of being simultaneously protected by a protective group, as a main constituent of a binder in an image-receiving layer. CONSTITUTION:A resin comprising at least one functional group having at least two hydroxyl groups located sterically close to each other in the state of being simultaneously protected by a protective group is used as a main constituent of a binder in an image-receiving layer. The resin generates hydroxyl groups when being hydrolyzed or decomposed through hydrogen addition by a desensitizing liquid or dampening water used at the time of printing. Therefore, when an image is drawn on the image-receiving layer of a direct drawing type planographic plate material comprising the resin in a surface layer, by using an oil based ink or the like as a printing area, the oleophilic functional groups having hydroxyl groups being protected ensure favorable adhesion between the image receiving layer and the oil based ink or the like, whereby plate wear characteristics are enhanced. In a non-image area, the oleophilic functional groups are hydrolyzed or decomposed through hydrogen addition by the desensitizing liquid and dampening water to become hydroxyl groups, whereby the non-image area is made to be hydrophilic, as clearly contrasted to the oleophilic property of the printing area. Thus, a printing ink is prevented from being adhered to the non-image area at the tine of printing.
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