A block copolymer pressure-sensitive adhesive , the pressure-sensitive adhesive composition and the surface protective film .

摘要

PROBLEM TO BE SOLVED: To provide a block copolymer for a tacky adhesive, which can maintain a stable tacky adhesiveness properly for a long period and exerts the same level of tacky adhesiveness even under a low-temperature condition as that under a room-temperature condition.;SOLUTION: The block copolymer comprises two polymer blocks (A1, A2) having a vinyl aromatic monomer unit as a main component and a polymer block B having at least one hydrogenated conjugate diene monomer unit as a main component, and is equipped with the following conditions (1) to (5): (1) the content of the vinyl aromatic monomer unit of 15 to 30 mass%; (2) the mass ratio (A1/A2) of the polymer block (A1) to the polymer block (A2) of 0.9 to 1.1; (3) the vinyl bond content of the conjugate diene monomer unit before hydrogenation of 30 to 40%; (4) the melt flow rate (at 230°C, 2.16 kg-load) of 10 to 16 g/10 min; and (5) having a peak of tan δ(loss tangent) in the range of -35 to -45°C of the block copolymer.;COPYRIGHT: (C)2013,JPO&INPIT