| 摘要 |
PROBLEM TO BE SOLVED: To provide a photosensitive composition for a litho-graphic printing plate high in sensitivity, underdevelopability, overdevelopability, resistance to chemicals, exposure image-visualizability, and gradation. SOLUTION: This photosensitive composition for a lithographic printing plate comprises a novolak resin obtained by condensation of phenols composed essentially of pure phenol with aldehydes or ketones and a quinonediazido compound, and this novolak resin has an area of 30-90% and 0-40% and 20-90% of the total area of GPC patterns in the range of a weight average molecular weight of 6,000-30,000 and 2,000-5,000 and 150-1,000 in terms of a monodispersed polystyrene measured by the gel permeation chromatography(GPC), that is, the novolak resin comprises a combination of two or more kinds of the novolak resins different from each other in the weight average molecular weight. |
