Photosensitive resin composition

Abstract

Printing plate stock comprising a base, a photosensitive resin layer overlying the base, and a covering layer overlying the photosensitive resin layer, characterized in that said photosensitive resin layer comprises (i) a matrix phase comprising a hydrophobic polymer, and (ii) a dispersed phase, surrounded by said matrix phase, comprised of particles, wherein each of said particles comprises a hydrophobic polymer surrounded by a hydrophilic polymer, wherein said hydrophilic polymer is 5-30% wt of said photosensitive resin layer.

What is claimed is:  
     
         1 . A photosensitive resin composition which comprises (A) a hydrophobic polymer having a glass transition temperature not higher than 5° C., (B) a hydrophilic polymer, (C) an ethylenic unsaturated compound, (D) a solvent capable of dissolving said component (B) more than said component (A), and (E) a photopolymerization initiator, with said component (B) being less in content than said component (A).  
     
     
         2 . A photosensitive resin composition according to    claim 1   , wherein the hydrophilic polymer (B) contains a group represented by the formula —COOM (where M denotes a hydrogen atom, an element belonging to Groups I, II, and III of the Periodic Table, amine, or ammonium) in an amount of 50-50,000 equivalents/10 6  g.  
     
     
         3 . A photosensitive resin composition according to    claim 1   , wherein the content of the solvent (D) is 0.001 to 2.0 wt %.  
     
     
         4 . A printing plate stock having a base, a photosensitive resin layer, and a covering layer arranged one over another, characterized in that said photosensitive resin layer contains, as a dispersed phase, particles each composed of a phase consisting mainly of a hydrophobic polymer surrounded by a phase consisting mainly of a hydrophilic polymer.  
     
     
         5 . A printing plate stock according to    claim 4   , wherein said particles are partly in the form of aggregate.  
     
     
         6 . A printing plate stock according to    claim 4   , wherein said particles are dispersed in a density higher than 1×10 2  per cm 2 .  
     
     
         7 . A finished printing plate having a base and a photosensitive resin layer formed thereon, characterized in that said photosensitive resin layer contains, as a dispersed phase, particles each composed of a phase consisting mainly of a hydrophobic polymer surrounded by a phase consisting mainly of a hydrophilic polymer.  
     
     
         8 . A finished printing plate according to    claim 7   , wherein said particles are partly in the form of aggregate.  
     
     
         9 . A finished printing plate according to    claim 7   , wherein said particles are dispersed in a density higher than 1×10 2  per cm 2 .  
     
     
         10 . A method for producing a photosensitive resin layer containing (A) a hydrophobic polymer having a glass transition temperature not higher than 5° C., (B) a hydrophilic polymer, (C) an ethylenic unsaturated compound, (D) a solvent capable or dissolving said component (B) more than said component (A), and (E) a photopolymerization initiator, which comprises removing the component (D), at any stage of the production, so as to be a content of 0.001-2 % by weight.  
     
     
         11 . A method according to    claim 10   , wherein the removal of the component (D) is effected while stirring and mixing the components (A), (B), (C), (D) and (E).