Pressure-sensitive adhesive composition

An optical device having a surface,

• wherein a protective film is adhered to the surface,
• wherein the protective film comprises a base film for protecting the surface and a pressure-sensitive adhesive layer on one surface of the base film,
• wherein the pressure-sensitive adhesive layer comprises a crosslinked pressure-sensitive adhesive composition,
• wherein the pressure-sensitive adhesive composition comprises:
• a polymer comprising a polymerization unit of a hydroxyalkyl (meth)acrylate in which an alkyl group has 1 carbon atom or 2 carbon atoms and a polymerization unit of a monomer represented by Formula 1;
• and an aliphatic isocyanate crosslinking agent,
• wherein the polymer does not include a polymerization unit induced from a carboxyl group-containing monomer,
• wherein crosslinking points of the polymer reacted with the crosslinking agent are only hydroxyl groups included in the polymerization unit of the hydroxyalkyl (meth)acrylate in which the alkyl group has 1 carbon atom or 2 carbon atoms or the polymerization unit of the monomer represented by Formula 1, wherein a weight ratio of the hydroxyalkyl (meth)acrylate in which the alkyl group has 1 carbon atom or 2 carbon atoms with respect to the monomer of Formula 1 in the polymer is more than 1 and not more than 5, and
• wherein the surface of the optical device has a surface energy of 30 mN/m or less, and the pressure-sensitive adhesive layer of the protective film is directly adhered on the surface having the surface energy of 30 mN/m or less:
• where the “Q” is hydrogen or an alkyl group, the “T” is an alkylene group, the “m” is a number ranging from 1 to 16, and a multiplication (m×c) of the “m” and the number (c) of carbon atoms in the alkylene group of the “T” is 4 or more.