| 摘要 |
PURPOSE:To obtain a material for a lithographic printing plate having superior photosensitivity without deteriorating the developability or the suitability to exposure giving a visible image by forming a photosensitive layer contg. a compound producing an acid by exposure and a prescribed compound on a support. CONSTITUTION:A photosensitvie layer of a photosensitive composition contg. a compound producing an acid by exposure and a compound having at least three acetal bonds which are decomposed by the acid in the molecule is formed on a support. Novolak resin represented by formula I (where Ar is an aromatic group, R<1> is 2-cyclic ether, each of R<2> and R<3> is H, alkyl or phenyl and n>=3) may be used as the compound having at least three acetal bonds in the molecule. The about of the compound used is 20-80wt%, preferably 50-60wt% of the total amount of the solid substances in the photosensitive composition. An alkali-soluble resin such as cresol-formaldehyde resin or phenol-cresol formaldehyde resin may be added to the composition. |
