Photopolymerizable presensitized plate for use in making lithographic printing plate and method for making lithographic printing plate

Abstract

The present invention provides a PS plate for use in making a lithographic printing plate, comprising an aluminum substrate provided thereon with a light-sensitive layer comprising a polyurethane resin binder, an addition polymerizable ethylenically unsaturated bond-containing compound and a photopolymerization initiator, wherein the polyurethane resin binder is one synthesized from at least the following compounds (i) to (iv): (i) at least one di-isocyanate compound; (ii) at least one diol compound having at least one carboxyl group; (iii) at least one diol compound whose log P value is less than 0; and (iv) at least one diol compound whose log P value is higher than 0. The PS plate and a method for making a lithographic printing plate therefrom according to the present invention satisfy the requirements for high resistance to staining and high printing durability, which permits the dissolution, in a developer, of the foregoing compounds insoluble in the developer or the stable dispersion of the compounds in the developer over a long period of time and improve the stable processing ability of the developer, without impairing the image-forming ability at all.