Patent ID: 8426543

Claim:
An adhesive composition comprising, as a main component, a polymer produced by copolymerization of a monomer composition including: styrene; at least one (meth)acrylic acid alkyl ester having a chain structure; a (meth)acrylic acid ester having an aliphatic ring; and a (meth)acrylic acid ester having an aromatic ring, wherein the (meth)acrylic acid ester having the aliphatic ring is a compound represented by the following formula (2) wherein R 3 is a hydrogen atom or a methyl group; and R 4 is a C4 to C15 organic group having an aliphatic ring, wherein: the styrene is contained in a range of 40 to 69 parts by mass; the (meth)acrylic acid alkyl ester having the chain structure is contained in a range of 20 to 30 parts by mass; the (meth)acrylic acid ester having the aliphatic ring is contained in a range of 10 to 25 parts by mass; and the (meth)acrylic acid ester having the aromatic ring is contained in a range of 1 to 5 parts by mass, where the amount of styrene, the (meth)acrylic acid alkyl ester having the chain structure, the (meth)acrylic acid ester having the aliphatic ring, and the (meth)acrylic acid ester having the aromatic ring is based on 100 parts by mass of the total monomer composition, and the polymer has a glass transition temperature in a range of 65° C. to 95° C.