Pressure-sensitive adhesive composition having high shear strength

摘要

This invention provides a normally tacky pressure-sensitive adhesive composition comprising (1) a radial teleblock copolymer having at least three monoalkenyl arene polymer blocks and a branched elastomeric conjugated diene polymer block, (2) a tackifying resin, and (3) from about 5 to about 20 parts by weight extending oil per 100 parts by weight of radial copolymer. The copolymer preferably has a molecular weight of about 180,000 to about 250,000, as expressed in polystyrene equivalent molecular weight units. The monoalkenyl arene polymer blocks preferably comprise from about 17% to about 23% by weight of the total molecular weight of the copolymer. The preferred polymer for the monoalkenyl arene block is polystyrene; the preferred polymer for the elastomeric conjugated diene block is polyisoprene.