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.

Abstract: A photosensitive resin composition includes (A) a hydrophobic polymer having a glass transition temperature not greater than 5.degree. C., (B) a hydrophilic polymer, (C) an ethylenically unsaturated compound, (D) a solvent capable of dissolving the component (B) more than the component (A) and (E) a photopolymerization initiator, with the content of component (B) being less than that of component (A). The resin composition can be used to prepare a printing plate having a base, a photosensitive resin layer and a covering layer arranged one over another. The photosensitive resin layer contains a dispersed phase which includes particles having a phase which includes a hydrophobic polymer, surrounded by a phase which includes a hydrophilic polymer. The photosensitive resin layer can be prepared by removing the solvent (D) to a content of 0.001-2% by weight.

Abstract: A photosensitive resin composition includes (A) a hydrophobic polymer having a glass transition temperature not greater than 5.degree. C., (B) a hydrophilic polymer, (C) an ethylenically unsaturated compound, (D) a solvent capable of dissolving the component (B) more than the component (A) and (E) a photopolymerization initiator, with the content of component (B) being less than that of component (A). The resin composition can be used to prepare a printing plate having a base, a photosensitive resin layer and a covering layer arranged one over another. The photosensitive resin layer contains a dispersed phase which includes particles having a phase which includes a hydrophobic polymer, surrounded by a phase which includes a hydrophilic polymer. The photosensitive resin layer can be prepared by removing the solvent (D) to a content of 0.001-2% by weight.

Abstract: Disclosed herein are a process and apparatus for developing photopolymer plates which are useful for flexographic printing on account of their rubber-like elasticity, capability for development by water washing, and good ink resistance. The process and apparatus are designed to circulate by force the washout solution during the development operation in order to minimize the aggregation of photopolymer particles suspending in the washout solution and to completely catch scum which occurs when the unexposed part of the polymer plate is rubbed off in the washout solution.

Abstract: The invention provides a photosensitive resin composition containing a soluble synthetic linear high-molecular compound in an amount of 25 to 95 weight percent based on the whole composition, a monomer having at least one photopolymerizable unsaturated bond and a photopolymerization initiator and characterized in that part or all of the soluble synthetic linear high-molecular compound is an addition polymer of an organic diisocyanate compound with an amide compound, both terminals of the amide compound being either primary or secondary amide groups and the equivalent ratio of amino groups to isocyanate groups in the addition polymer is not less than 1.0. The high-molecular weight compound makes up at least 50% by weight base on the total amount of the polymer material present in the composition.

Abstract: A photosensitive resin composition which comprises a polymer having a basic nitrogen atom in the main or side chain, which is represented by the formula: ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 are each a hydrogen atom or a substituted or unsubstituted hydrocarbon group, at least one of R.sub.1 to R.sub.3 representing a polymeric chain, a photopolymerizable unsaturated monomer and a photosensitizer.

Abstract: Photosensitive polyamide resin composition which can be developed with water to give a relief printing plate having an excellent moisture resistance, comprising 30 to 90% by weight of a water-soluble polyamide having ammonium type nitrogen atoms and 5 to 70% by weight of a photopolymerizable unsaturated compound prepared by reacting (meth)acrylic acid (I) and a polyglycidyl ether of an aliphatic polyvalent alcohol (II) in an equivalent ratio of 0.5.ltoreq.(I)/(II).ltoreq.2.0, and 0.01 to 10% by weight of a photopolymerization initiator.

Abstract: A photosensitive resin composition which comprises a polyester having a nitrogen atom in the ammonium salt form in the main or side chain representable by the formula: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each a hydrogen atom or a substituted or unsubstituted hydrocarbon group, at least one of R.sub.1 to R.sub.4 representing a polymeric chain, and X is an anion to be paired with the ammonium ion, a photopolymerizable unsaturated monomer and a photosensitizer.

Abstract: A photosensitive resin composition which comprises a polymer having a basic nitrogen atom in the main or side chain, which is represented by the formula: ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 are each a hydrogen atom or a substituted or unsubstituted hydrocarbon group, at least one of R.sub.1 to R.sub.3 representing a polymeric chain, a photopolymerizable unsaturated monomer and a photosensitizer.