| 摘要 |
PROBLEM TO BE SOLVED: To provide a lithographic printing plate having excellent sensitivity, developing property and printing durability required for a positive photosensitive lithographic printing plate, and having excellent ball-point pen suitability based upon a ball-point pen test. SOLUTION: At least two photosensitive layer containing a compd. which produces acids or radicals by irradiation of light, active radiation or electron beams are formed on a supporting body of this printing plate. The uppermost photosensitive layer and at least one photosensitive layer except for the uppermost layer are formed to have different physical properties described below. Moreover, the photosensitive layers contain polymer compds. The physical properties are (1) microindentation hardness, (2) plastic deformation, (3) Young's modulus, (4) fracture strength and (5) fracture elongation. Further, in the photosensitive layers containing polymer compds. above described, the value (D1) defined by D=Σμm×Mm/100 for the polymer in the uppermost layer is made different from the value (D2) for the polymer in the photosensitive layer except for the uppermost layer. In the formula,μm is the dipolar moment (D) of each monomer unit which constitutes the polymer compd., and Mm is the mol% of each monomer unit which constitutes the polymer compd. |
