| 摘要 |
PROBLEM TO BE SOLVED: To provide an original plate for a lithographic printing plate requiring no damping water which shows high shelf stability, high sensitivity to a writing laser and a high-safety recording layer generating no harmful substance during recording. SOLUTION: This original plate for the lithographic printing plate requiring no damping water comprises a photothermal conversion layer for converting a laser light to heat and a silicone rubber layer laminated, in that order, on a support. The photothermal conversion layer is characterized in that it contains a photothermal conversion agent and a polyurethane which has at least one kind of a carboxyl group and uses a diol compound and an isocyanate compound as raw materials and is compounded at such a molar ratio of 1.03 or less of an isocyanate group of the isocyanate compound to the total amount of a hydroxyl group of the diol compound and a hydroxyl group contained in the moisture of a reaction system. |
