Toray Industries, Inc.

Tamio Adachi

Shigetora Kashio

Shinji Tanaka

Michihiko Ichikawa

Hiroshi Tamada

Yoshiki Ichii

A photosensitive resin printing plate precursor including: a photosensitive resin layer (A) containing a water-soluble or water-dispersible resin and an ultraviolet-curable monomer; and a water-insoluble heat-sensitive mask layer (C) containing an infrared-absorbing material, deposited in that order on a support is disclosed. By introducing a crosslinked structure or a hydrophobic constituent to the heat-sensitive mask layer (C) so as to be insoluble in water, a difference in polarity is produced between the layers (A) and (C) and, thus, mass transfer between the two layers can be prevented. Also, the scratch resistance of the heat-sensitive mask layer (C) can be dramatically enhanced and, thus, the printing plate precursor becomes easy to handle.

Photosensitive resin printing plate original, process for producing the same and process for producing resin relief printing plate therewith

Disclosed are a photosensitive resin composition essentially comprising 100 parts by weight of modified polyvinyl alcohol comprising a structural units of formulae (I), (II) and (III): ##STR1## wherein R represents a hydrocarbon group having 1 to 20 carbon atoms; X represents an aliphatic, alicyclic or aromatic divalent hydrocarbon group having 1 to 20 carbon atoms or a divalent group having at least one carboxyl group in the molecule thereof, the proportion of the structural unit of formula (I) being from 1 to 40 mol %, the total proportion of the structural units of formulae (II) and (III) being from 60 to 99 mol %, and the carboxyl equivalent attributed to the structural unit of formula (III) being from 0.3 to 5 mol/kg, (B) from 0.1 to 10 parts by weight of an unsaturated epoxy compound, (C) from 20 to 200 parts by weight of a polymerizable unsaturated compound having an ethylenical double bond in the molecule thereof, and (D) from 0.1 to 10 parts by weight of a photopolymerization initiator. A photosensitive resin composition containing modified polyvinyl alcohol obtained by reacting partially saponified polyvinyl alcohol having a degree of saponification of 60 to 99 mol % and a number average degree of polymerization of 300 to 2,000 with a carboxylic acid anhydride in a molten state is also disclosed. Additionally, and a process for producing a photopolymerizable resin composition comprising reacting partially saponified polyvinyl alcohol having a degree of saponification of 60 to 99 mol % and a number average degree of polymerization of 300 to 2,000 with a carboxylic acid anhydride in a molten state to prepare (A-2) modified polyvinyl alcohol and mixing modified polyvinyl alcohol (A-2) with (C) a polymerizable unsaturated compound having an ethylenical double bond in the molecule thereof, and (D) a photopolymerization initiator is disclosed. The photosensitive resin compositions provide a printing plate material having high sensitivity and highly precise image reproducibility, from which material is obtained a printing plate whose relief has excellent toughness. The use of the modified polyvinyl alcohol obtained by a molten reaction makes it easy to prepare a solution of a photosensitive resin composition.

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Okazaki, Japan

Tamio Adachi