JPS5453187A - Photo-setting resin composition - Google Patents

Abstract

PURPOSE: To obtain the title composition suitable for a relief of letterpress printing having improved printability, capable of aqueous solvent developing, consisting of a reaction product of a specific unsaturated polyester and glycidyl methacrylate, an thylenic unsaturated monomer, and a photosensitizer.

CONSTITUTION: A) An unsaturated polyester is obtained by polycondensation of (a) an acid component consisting of (1) 5-30 mol.% of a tri-or polycarboxylic acid, such as trimesic acid, etc., (2) preferably 30-80 mol.% of an unsaturated dicarboxylic acid, such as maleic acid, and (3) 0-70 mol.% of a dicarboxylic acid, such as phthalic acid, etc., and (b) a glycol component, such as ethylene glycol. The resulting polyester is reacted with glycidyl methacrylate in an amount preferably 3-75 wt.% based on the total equivalent weight of carboxyl groups in the polyester. A) The resulting product is incorporated with B) a monomer having an ehylenic unsaturated double bond (e.g. styrene, etc.) in an amount preferably 20-75 wt.% based on the component A). A photosensitizer e.g. benzoin is added to the resulting blend thus obtained to give the desired composition

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