PRESSURE-SENSITIVE ADHESIVE FOR OPTICAL FILMS

摘要

[PROBLEMS] To provide a pressure-sensitive adhesive for optical films which exhibits high cohesive force, and excellent reworkability, pressure-sensitive adhesion characteristics, heat resistance and endurance in spite of its dispensing with chemical crosslinking. [MEANS FOR SOLVING PROBLEMS] A pressure-sensitive adhesive for optical films which contains at least 60% by mass (based on the whole solid matter) of an acrylic triblock copolymer (I) represented by the general formula: A1-B-A2 in which alkyl methacrylate polymer blocks (A1) and (A2) having Tg of 100°C or above are bonded to an acryl acrylate polymer block (B) having Tg of -20°C or below and which has a block (B) content of 50 to 95% by mass, Mw of 50,000 to 300,000 and a molecular weight distribution of 1.0 to 1.5. It is preferable to use as the acrylic triblock copolymer (I) a blend which comprises an acrylic triblock copolymer (Ia) having Mw of 50,000 or above but below 100,000 and an acrylic triblock copolymer (Ib) having Mw of 100,000 to 300,000 at a (Ia):(Ib) mass ratio of 45:55 to 75:25.