Japan Synthetic Rubber Co., Ltd.

Mitsuo Kurokawa

Koei Komatsu

Isao Nagaoka

Fumitake Imaizumi

Yoshiyuki Harita

Kunihiro Harada

Yoshihiro Hosaka

Yasuyuki Takimoto

Eijiro Tagami

Hidefumi Kusuda

A photosensitive resin composition comprising (I) a copolymer containing (A) 10 to 95 mol % of a conjugated diolefinic hydrocarbon, (B) 5 to 90 mol % of an .alpha.,.beta.-ethylenically unsaturated carboxylic acid and (C) 0 to 85 mol % of a monoolefinically unsaturated compound, (II) a photosensitizer and/or a photosensitive crosslinking agent, and, if necessary, (III) a photopolymerizable unsaturated monomer. Said copolymer may have been reacted with an inorganic alkali, an alkali salt or an amine compound in a proportion of 0.05 to 1.0 equivalent per equivalent of the carboxyl group of the .alpha.,.beta.-ethylenically unsaturated carboxylic acid in said copolymer. This photosensitive resin composition is excellent in storage stability, quick in photosetting upon exposure to actinic light rays including ultraviolet rays, that is, high in sensitivity, capable of development with water or a dilute aqueous alkaline solution and possesses satisfactory rubber elasticity, and a printing plate formed from the composition is excellent in water resistance though the composition is developable with an aqueous developing solution, so that the composition can be used for a flexographic printing plate, to which an aqueous flexographic printing ink can be applied. Said composition can also be used for a pohote-resist which is high in sensitivity, developable with water or a dilute alkaline solution and excellent in resolving power.

Photosensitive compositions and printing plates containing same

A process for producing a maleic anhydride adduct of high molecular weight 1,2-polybutadiene by contacting with heat maleic anhydride with high molecular weight 1,2-polybutadiene in the absence of a radical initiator in a halogenated aromatic hydrocarbon solvent. The adduct obtained by this process has a high molecular weight of more than 10,000 and is quite free from gel. Said process enables the addition of maleic anhydride in any desired proportion.

Process for producing maleic anhydride adduct of high molecular weight

A photosensitive composition comprising (1) a maleic anhydride adduct of 1,2-polybutadiene having a molecular weight of 10,000 or higher, (2) at least one photosensitizer and/or at least one photosensitive crosslinking agent, and, if necessary, (3) at least one acrylic monomer. This composition can be developed with water or a polar solvent such as an alcohol, and its layer formed on a support provides a printing plate. When the acrylic monomer is contained, the composition is suitable for use in flexographic printing.

Photosensitive composition using maleic anhydride adduct of a 1,2

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Yokohama, Japan

Mitsuo Kurokawa