Multi-arm block copolymer, and pressure sensitive adhesive and tape employing a multi-arm elastomeric block copolymer.

摘要

The present invention provides a novel multi-arm block copolymer, a novel pressure-sensitive adhesive made from a multi-arm elastomeric block copolymer, and a novel tape made therefrom. The multi-arm block copolymer has the general structure (A-B)mY(C-D)n wherein A, B, C and D are polymer segments; Y is a residue of a multifunctional coupling agent; and m and n are the number of arms, where m and n are greater than 0 and the sum of m plus n is at least 3. A comprises a random copolymer of a monoalkenylarene and a conjugated diene; B and C comprise either a homopolymer of a conjugated diene or a polymer of two or more conjugated dienes; D comprises either a homopolymer of a monoalkenylarene or a copolymer of a monoalkenylarene and a conjugated diene wherein the Tg of D is greater than the Tg of A; and the weight percent of monoalkenylarene in the block copolymer is 40% or less. The pressure-sensitive adhesive of the invention comprises 100 parts by weight of either the previously described multi-arm block copolymer or a multi-arm block copolymer having the structure (A'-B)mY, about 20 to about 300 parts by weight of a tackifying resin, 0 to about 50 parts by weight of a crosslinking agent, and 0 to about 200 parts by weight of a plasticizer.