Abstract: A photosensitive constituent for a flexographic printing plate comprising a polyester film as support (B) and a photosensitive elastomer composition (C) and having an adhesive layer (A) therebetween, wherein the photosensitive elastomer composition (C) comprises, as essential components, (a) 50% by weight or more of at least one thermoplastic elastomer comprising a mono-vinyl-substituted aromatic hydrocarbon and a conjugated diene, (b) 5 to 40% by weight of at least one diene-based liquid rubber, (c) 1 to 20% by weight of at least one ethylenically unsaturated compound having 2 unsaturated bonds within its molecule, and (d) 0.1 to 3% by weight of at least one photopolymerization initiator, and wherein (1) the thermoplastic elastomer has an average ratio of vinyl bond units in conjugated diene segments thereof of 10 to 20 mol % and (2) the liquid rubber has a number average molecular weight (Mn) of 500 to 5,000 and an average ratio of vinyl bond units of 50 to 70 mol %.

Abstract: A photosensitive constituent for a flexographic printing plate comprising a polyester film as support (B) and a photosensitive elastomer composition (C) and having an adhesive layer (A) therebetween, wherein the photosensitive elastomer composition (C) comprises, as essential components, (a) 50% by weight or more of at least one thermoplastic elastomer comprising the reaction product of a mono-vinyl-substituted aromatic hydrocarbon monomer and a conjugated diene monomer, (b) 5 to 40% by weight of at least one diene-based liquid rubber, (c) 1 to 20% by weight of at least one ethylenically unsaturated compound having 2 unsaturated bonds within its molecule, and (d) 0.1 to 3% by weight of at least one photopolymerization initiator, and wherein (1) the thermoplastic elastomer has an average ratio of vinyl bond units in conjugated diene segments thereof of 10 to 20 mol % and (2) the liquid rubber has a number average molecular weight (Mn) of 500 to 5,000 and an average ratio of vinyl bond units of 50 to 70 mol %.

Abstract: A photosensitive element for flexographic printing which is composed of (a) a support layer; (b) a photosensitive resin layer which comprises, as a binder polymer, a thermoplastic elastomer obtained by polymerization of a monovinyl-substituted aromatic hydrocarbon and a conjugated diene, said photosensitive resin layer (b) being placed on the support layer (a); and (c) a non-infrared ray-shielding layer which can be ablated with an infrared laser, and comprises a binder polymer, an infrared absorber and a non-infrared ray-shielding material, said non-infrared ray-shielding layer (c) being placed on the photosensitive resin layer (b), wherein the binder polymer of the non-infrared ray-shielding layer (c) is a copolymer composed of a monovinyl-substituted aromatic hydrocarbon and a conjugated diene or a hydrogenation product of a copolymer composed of a monovinyl-substituted aromatic hydrocarbon and a conjugated diene.