| 摘要 |
An active energy ray-curable sealing agent composition, comprising (A) at least one unsaturated group-containing urethane oligomer having a number average molecular weight Mn of from 1,000 to 100,000 and a degree of unsaturation of from 0.1 to 1 mol/kg obtained by reacting at least one hydrogenated diene-based oligomer diol (a) having a number average molecular weight Mn of from 500 to 3,000, at least one bifunctional epoxy (meth)acrylate (b) containing two hydroxyl groups and two ethylenically unsaturated groups in the molecule thereof, and at least one polyisocyanate (c); (B) at least one (meth)acrylic ester monomer obtained by esterification of (meth)acrylic acid or a (meth)acrylic acid derivative with an alcohol of the formula R—OH, wherein R corresponds to an organic radical containing 1 to 20 carbon atoms and having a molecular weight of 1,000 or less; and (C) at least one photopolymerization initiator; exhibits an improved curability and is suitable for the preparation of gaskets exhibiting low hardness, enhanced flexibility and elongation, enhanced durability, and very low moisture vapor transmission rate for encasing high precision electronic instruments. |
