| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a positive lithographic printing original plate for IR laser for direct platemaking, the plate which suppresses production of a residual film during development, which can form an image with excellent contrast and which has excellent sensitivity/storage stability. <P>SOLUTION: The plate has an image recording layer formed on a hydrophilic supporting body. The layer contains (A) a novolac phenol resin prepared by condensing phenol and alkyl-substituted phenol with the molar fraction of the phenol higher than the molar fraction of the alkyl substituted phenol, and (B) a photo-thermal converting agent. The layer increases its solubility with an alkali aqueous solution by exposure to IR laser light. The novolac phenol resin is preferably a resin prepared by condensing phenol and substituted phenols expressed by general formula (I), cresol or xylenol with aldehydes. In formula (I), each of R<SP>1</SP>and R<SP>2</SP>represents a hydrogen atom, an alkyl group or a halogen atom, and R<SP>3</SP>represents an alkyl group or a cycloalkyl group. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
