Pressure sensitive adhesive composition and intermediate copolymers for the preparation thereof.

摘要

A coupled alkenyl aromatic compound-conjugated diene block copolymer having a total bound alkenyl aromatic compound content from 3 to 70% by weight is represented by the general formula: [(A-B)m]n X or [(A-B-A min m]n X wherein A and A min are each blocks of an alkenyl aromatic compound polymer, B is a block of a conjugated diene polymer or a block of a conjugated diene-alkenyl aromatic compound copolymer, X is the residue of a tin coupling agent or a mixture of the residue of a tin coupling agent and the residue of a non-tin coupling agent, m is an integer of 1 or more and n is an integer from 2 to 4 corresponding to the functionality of X. This coupled block copolymer is suitable for use in hot-melt pressure-sensitive adhesives, and pressure-sensitive adhesive compositions containing 100 parts by weight of a block copolymer containing at least 20% by weight of said coupled block copolymer, 20 to 200 parts by weight of a tackifier, 0 to 20 parts by weight of an organic acid and 0 to 100 parts by weight of a softener are effectively used in such applications as pressure-sensitive adhesive tapes, labels, backing pastes for fixing light weight plastic articles and backing pastes for fixing carpets.