Abstract: A presensitized plate, for use in making a lithographic printing plate requiring no dampening water, comprises a substrate, a light-sensitive resin layer applied thereon and a silicone rubber layer formed on the light-sensitive layer which is cross-linked through a reaction of SiH groups with --CH.dbd.CH-- groups, the light-sensitive resin layer comprising:(1) a monomer or an oligomer having at least one photopolymerizable (meth)acryloyl group and at least one allyl group;(2) a photopolymerization initiator; and optionally(3) a polymeric compound having film-forming ability; and(4) a monomer or an oligomer having at least one photopolymerizable (meth)acryloyl groups and free of allyl groups.According to the presensitized plate, the adhesion between the addition type silicone rubber layer and the light-sensitive resin layer is greatly improved and excellent image-forming properties of the presensitized plate are thus ensured.

Abstract: A developer for PS plates requiring no dampening water which comprise a substrate provided thereon with a primer layer, photopolymerizable light-sensitive layer and a silicone rubber layer in this order, comprises: (i) an organic solvent which can dissolve or swell non-exposed portions of the photopolymerizable light-sensitive layer and whose solubility in water at ordinary temperature is not more than 20% by weight; (ii) a surfactant; and (iii) water. The developer is excellent in developing properties and dot reproduction, shows high stability and does not cause scratches on the silicone rubber layer during development.

Abstract: Disclosed is a process for preparing an image-bearing plate for use in a lithographic printing plate, a photoresist or the like. The process comprises, after imagewise exposing a light-sensitive plate comprising a support having provided thereon a light-sensitive layer comprising a compound capable of producing an acid upon irradiation with actinic rays, a compound having at least one acid-decomposable group, and an alkali-soluble resin, treating the exposed plate with hot water of at least 25.degree. C. for a period of at least 10 seconds, prior to development. It is possible to achieve high sensitivity regardless of the interval between the exposure and the development.

Abstract: The present invention relates to a photosensitive lithographic plate necessitating no damping water, which plate has an excellent image reproducibility and stability in the lapse of time. The plate comprises, on a support, a photosensitive layer and a silicone rubber layer in this order, the silicone rubber layer being formed by addition reaction of an SiH group with a --CH.dbd.CH- group to cause crosslinking, and the photosensitive layer comprising:(1) a polymer comprising at least a structural formula (I): ##STR1## wherein R represents a hydrogen atom or a methyl group; R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.

Abstract: A light-sensitive composition is herein disclosed, which comprises at least one light-sensitive s-triazine compound represented by the following general formula (I) and at least one compound having at least one ethylenically unsaturated double bond and capable of causing addition polymerization: ##STR1## wherein R.sub.1 and R.sub.2 independently represent hdyrogen atom, a substituted or unsubstituted alkyl or aryl group, or a group represented by the general formula: R.sub.5 --CO-- or N(R.sub.6) (R.sub.7)--CO-- (wherein R.sub.5 stands for a substituted or unsubstituted alkyl or aryl group; and R.sub.6 and R.sub.7 independently represent hydrogen atom or a substituted or unsubstituted alkyl or aryl group), provided that R.sub.1 and R.sub.2 may form a heterocyclic ring consisting of non-metallic atoms together with the nitrogen atom to which they are bonded; R.sub.3 and R.sub.4 represent hydrogen, a halogen, an alkyl or an alkoxyl; X and Y independently represent chlorine or bromine; and m and n are 0, 1 or 2.

Abstract: A light-sensitive composition containing a polymerizable compound having at least one ethylenically unsaturated group, and a photopolymerization initiator of general formula (I): ##STR1## wherein Y represents --COOR.sub.1, ##STR2## --R.sub.3 --COOR.sub.1, --R.sub.3 --CONHR.sub.1 or --NHCO--R.sub.4 (wherein R.sub.1 represents a hydrogen atom, an alkyl group, or an aryl group; R.sub.2 represents a hydrogen atom or a methyl group; R.sub.3 represents an alkylene group; R.sub.4 represents an alkyl group, an alkoxy group, an aryl group; and l and m respectively represents integers of 1 to 10.); Ar represents a phenylene, naphthylene or heterocyclic aromatic group; X represents a chlorine atom or a bromine atom; and n represents 1 or 2.The light-sensitive composition has a good stability over time since crystallization of the photopolymerization initiator on the surface of the light-sensitive layer is inhibited.

Abstract: The present invention relates to a photopolymerizable composition which comprises(i) a monomer having at least one ethylenic unsaturated radical which is photopolymerizable under actinic light,(ii) at least one photopolymerizable initiator selected from the group consisting of compounds represented by the formula (I) ##STR1## wherein X represents a halogen atom and Y represents --CH.sub.3, --NH.sub.2, --NHR', --NR.sub.2, --OR' (wherein R' represents alkyl, substituted alkyl, aryl or substituted aryl and R represents --CX.sub.3, alkyl, substituted alkyl, aryl, substituted aryl or substituted alkenyl) and compounds represented by the formula (II) ##STR2## wherein X and R are the same as those of the formula (I) respectively, and(iii) a carbazole compound represented by the formula (III) ##STR3## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7 and R.sub.