| abstract |
An ultraviolet-curable adhesive having an excellent moisture resistance and suitable for bonding optical disks having an information recording layer (vapor deposition layer), particularly optical disks having a thick vapor deposition layer, which contains, as essential components, (A) N-vinylpyrrolidone, (B) a urethane (meth)acrylate oligomer derived from a caprolactone-based polyol, an alicyclic diisocyanate and (meth)acrylic acid, and (C) a photopolymerization initiator containing (C-1) a photopolymerization initiator composed of only a carbon atom, a hydrogen atom and an oxygen atom without containing a nitrogen atom, a sulfur atom and a phosphorus atom and (C-2) a photopolymerization initiator containing a nitrogen atom and/or a sulfur atom in a (C-1)/(C-2) ratio of 70/30 to 100/0 by weight. |