text: The present invention relates to a photopolymerizable composition which is curable by irradiation of ultraviolet rays and more in detail, relates to a novel photopolymerizable composition particularly suitable as an etching-resist ink for the production of a printed-circuit board.
  As the etching-resist ink of an ultraviolet curing type, a composition containing polyester, hydroxyalkyl acrylate, a photopolymerizable monomer, a carboxylic acid having 2 to 36 carbon atoms and a photopolymerization-initiator (refer to Japanese Patent Application Laid-Open No. 51-2503 (1976) U.S. Pat. No. 3,953,214,) and a composition containing polyester, half ester of hydroxy alkyl acrylate and polybasic acid, a vinyl monomer having an ethylenic unsaturated bond and a photopolymerization-initiator, (refer to Japanese Patent Application Laid-Open No. 57-13444 (1982) U.S. Pat. No. 4,293,636) have been known.
  However, the techniques have a demerit that in the case of removing the resist-film by an aqueous alkaline solution, the resist-film is swollen and exfoliated without being dissolved and accordingly, the thus swollen and exfoliated film causes blockade of the filter or the spouting nozzle for the aqueous alkaline solution.
  As a result of the present inventors' studies for solving the above-mentioned problem, the present inventors have found a photopolymerizable composition suitable for preparing an etching-resist ink which is curable by irradiation of ultraviolet rays and in which the thus cured etching-resist ink is soluble in an aqueous alkaline solution, and based on the finding, the present invention has been attained.