Patent ID: 7491434

Claim:
A pressure sensitive adhesive article comprising: a backing having first and second major surfaces; and a pressure sensitive adhesive on at least a portion of at least one of the major surfaces of said backing, at least one of said backing and said adhesive has a rubber phase and comprises: (a) 100 parts by weight of a polymodal asymmetric elastomeric block copolymer; (b) at least one tackifier in an amount sufficient to raise the calculated Fox T g of the rubber phase of said adhesive to at least 245°K; (c) 0 to about 50 parts by weight of a crosslinking agent; and (d) 0 to about 300 parts by weight of a plasticizer; wherein said polymodal asymmetric elastomeric block copolymer has the formula Q n Y and comprises from about 4 to about 40 percent by weight of a polymerized monovinyl aromatic compound and from about 96 to about 60 percent by weight of polymerized conjugated diene, wherein: Q represents an individual arm of said block copolymer and has the formula S-B; n represents the number of arms Q in said block copolymer and is a whole number of at least 3; and Y is the residue of a multifunctional coupling agent; and further wherein: (a) S is a nonelastomeric polymer segment endblock of a polymerized monovinyl aromatic homopolymer, there being at least two different molecular weight endblocks in said copolymer, a higher molecular weight endblock and a lower molecular weight endblock, wherein: (i) the number average molecular weight of said higher molecular weight endblock (Mn) H is in the range of from about 5,000 to about 50,000; (ii) the number average molecular weight of said lower molecular weight endblock (Mn) L is in the range of from about 1,000 to about 10,000; and (iii) the ratio (Mn) H /(Mn) L is at least 1.25; and (b) B is an elastomeric polymer segment midblock which connects each arm to the residue of a multifunctional coupling agent (Y) and comprises a polymerized conjugated diene or combination of conjugated dienes, wherein when said adhesive comprises said block copolymer, wherein said adhesive comprises a foam having at least one substantially smooth major surface having an Ra value less than about 75 micrometers, as measured by laser triangulation profilometry, and said foam comprises a plurality of microspheres, at least one of which is an at least partially expanded expandable polymeric microsphere.