Patent ID: 8236417
Filing Date: 2012-08-07
Classification: C08L,C09J,Y10T

Abstract:
1. A pressure-sensitive adhesive for optical films that comprises an acrylic triblock copolymer (I) at not less than 60% by mass based on the total mass of all solids contained in the pressure-sensitive adhesive, the acrylic triblock copolymer meeting requirements (E1), (E2), (E3) and (E4): (E1) the acrylic triblock copolymer is represented by Formula (1): wherein A1 and A2 are each independently an alkyl methacrylate polymer block having a glass transition temperature of not less than 100° C. and B is an alkyl acrylate polymer block having a glass transition temperature of not more than −20° C.; (E2) the content of the polymer block B is 50 to 95% by mass; (E3) the weight average molecular weight (Mw) is in the range of 50,000 to 300,000; and (E4) the molecular weight distribution (Mw/Mn) is in the range of 1.0 to 1.5 wherein the acrylic triblock copolymer (I) is a combination comprising an acrylic triblock copolymer (Ia) and an acrylic triblock copolymer (Ib) in a mass ratio (Ia):(Ib) of 45:55 to 75:25, the acrylic triblock copolymer (Ia) meeting requirements (E1), (E2), (E3′) and (E4), the acrylic triblock copolymer (Ib) meeting requirements (E1), (E2), (E3″) and (E4): (E3′) the weight average molecular weight (Mw) is in the range of 50,000 to less than 100,000; and (E3″) the weight average molecular weight (Mw) is in the range of 100,000 to 300,000.