To obtain an acrylic pressure-sensitive adhesive composition which excels in the adhesion to a hardly adhering adherend and a surface undergone water repellency or antifouling treatment and the adhesion to a roughed surface, withstands long-term use, and furthermore excels in cohesion.
The acrylic pressure-sensitive adhesive composition has, as the major component, an acrylic copolymer obtained by the photopolymerization of a polymerizable composition comprising a monomer component having an alkyl (meth)acrylate having a 2-14C alkyl group and a polar group-containing vinyl monomer, and an acrylic monomer as the major component, an olefin polymer having a polymerizable unsaturated double bond at the terminal, and a photopolymerization initiator, and has a gel fraction represented by formula (1): gel fraction=(B/A)×100 (wherein A is a weight of the acrylic pressure-sensitive adhesive composition; and B is a dry weight of insolubles of the acrylic pressure-sensitive adhesive composition after dipping in 40°C tetrahydrofuran for 48 hours) in the range of 50-80%.
WATANABE JUICHI