ULTRAVIOLET-CURING COMPOSITION

摘要

PROBLEM TO BE SOLVED: To obtain an ultraviolet-curing composition which has low viscosity and can give a cured film of reduced curing shrinkage by including a urethane (meth)acrylate obtained by reacting a (meth)acrylic monomer obtained by reacting a hydroxyl-containing (meth)acrylate with a lactone compound with a polyisocyanate. SOLUTION: 1 mol. of a hydroxyl-containing (meth)acrylate is reacted with 1-50 mol. of a lactone compound at 50-80 deg.C in the presence of a Lewis acid to obtain a hydroxyl-containing (meth)acrylic monomer. This monomer is reacted with a polyisocyanate compound having an isocyanate equivalent in an amount sufficient to react with the hydroxyl equivalent of the monomer at 40-60 deg.C in the presence of a catalyst to obtain a urethane (meth)acrylate. 5 mass % obtained urethane (meth)acrylate is mixed with 95 mass % or above polymerizable monomer to obtain a composition having a viscosity (at 25 deg.C) of 200 mPa.s or below and a curing shrinkage of 8.5% or below.