| US 7,491,434 B2 | ||
| Adhesive for bonding to low surface energy surfaces | ||
| Ashish K. Khandpur, Lake Elmo, Minn. (US); JingJing Ma, Woodbury, Minn. (US); Mark D. Gehlsen, Eagan, Minn. (US); Bradley S. Momchilovich, Stillwater, Minn. (US); and John J. Stradinger, Roseville, Minn. (US) | ||
| Assigned to 3M Innovative Properties Company, St. Paul, Minn. (US) | ||
| Filed on Jun. 15, 2004, as Appl. No. 10/868,480. | ||
| Application 10/868480 is a continuation of application No. 10/203046, abandoned, previously published as PCT/US01/03463, filed on Feb. 02, 2001. | ||
| Application 10/203046 is a continuation in part of application No. 09/496831, filed on Feb. 02, 2000, granted, now 6,630,531. | ||
| Prior Publication US 2004/0229000 A1, Nov. 18, 2004 | ||
| This patent is subject to a terminal disclaimer. | ||
| Int. Cl. B32B 3/00 (2006.01) | ||
| U.S. Cl. 428—36.5 [524/474; 524/50; 524/571; 524/577; 521/146; 428/500; 428/521] | 16 Claims |
| 1. 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 Tg 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 Qn 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.
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