Siloxane-based gel adhesives and articles
Siloxane-based gel adhesives with improved shear holding power are prepared from curable compositions. The curable compositions include a siloxane fluid with a viscosity of at least 1,000,000 centiPoise, a siloxane-(meth)acrylate co-polymer, and siloxane tackifying resin. The curable compositions can contain an initiator or can be cured by e-beam radiation without an initiator. The siloxane-(meth)acrylate copolymer is the reaction product of a reaction mixture of an ethylenically unsaturated siloxane-containing macromer, an alkyl (meth)acrylate monomer; optionally a reinforcing monomer, and an initiator.
1. A curable composition, comprising:
63-80 parts by weight of at least one siloxane fluid with a viscosity of at least 1,000,000 centiPoise;
1-20 parts by weight of at least one siloxane-(meth)acrylate co-polymer; and
16-20 parts by weight of siloxane tackifying resin.
2. The curable composition of claim 1 , wherein the siloxane-(meth)acrylate co-polymer comprises a reaction product of a reaction mixture, the reaction mixture comprising:
at least one ethylenically unsaturated siloxane-containing macromer;
at least one alkyl (meth)acrylate monomer; and
an initiator.
3. The curable composition of claim 2 , wherein the reaction mixture further comprises a reinforcing monomer selected from the group consisting of an acid-functional (meth)acrylate monomer and a base-functional (meth)acrylate monomer.
4. The curable composition of claim 1 , wherein the at least one siloxane fluid with a viscosity of at least 1,000,000 centiPoise comprises a linear polydimethyl siloxane fluid.
5. The curable composition of claim 1 , wherein the curable composition is curable to a siloxane gel adhesive comprising a siloxane-based crosslinked matrix and extractable siloxane fluid upon exposure to actinic radiation.
6. The curable composition of claim 1 , wherein the curable composition further comprises a peroxide initiator.
7. A gel adhesive article comprising:
a substrate with a first major surface and a second major surface; and
a siloxane-based gel adhesive composition disposed on at least a portion of the first major surface of the substrate, wherein the siloxane-based gel adhesive composition comprises the cured reaction product of a curable composition comprising:
a siloxane fluid with a viscosity of at least 1,000,000 centiPoise;
a siloxane-(meth)acrylate co-polymer; and
siloxane tackifying resin.
8. The gel adhesive article of claim 7 , wherein the substrate comprises a polymeric film, a fabric, a non-woven, a foam, a paper, a mesh, an adhesive, or a release liner.
9. The gel adhesive article of claim 7 , wherein the siloxane-(meth)acrylate copolymer comprises the reaction product of a reaction mixture comprising:
at least one ethylenically unsaturated siloxane-containing macromer;
at least one alkyl (meth)acrylate monomer; and
an initiator.
10. The gel adhesive article of claim 9 , wherein the reaction mixture further comprises a reinforcing monomer selected from an acid-functional (meth)acrylate monomer or a base-functional (meth)acrylate monomer.
11. The gel adhesive article of claim 7 , wherein curable composition comprises:
63-80 parts by weight of at least one siloxane fluid with a viscosity of at least 1,000,000 centiPoise;
1-20 parts by weight of at least one siloxane-(meth)acrylate co-polymer; and
16-20 parts by weight of siloxane tackifying resin.
12. The gel adhesive article of claim 7 , wherein the gel adhesion article has a 180° Peel Adhesion value to stainless steel of at least 3.0 Newtons/inch.
13. The gel adhesive article of claim 7 , wherein the gel adhesion composition has a Static Shear Holding Power value with a 500 gram weight of at least 10,000 minutes.
14. A method for preparing a gel adhesive article comprising:
providing a substrate with a first major surface and a second major surface;
providing a curable composition that upon curing forms a siloxane-based gel adhesive composition, wherein the curable composition comprises:
a siloxane fluid with a viscosity of at least 1,000,000 centiPoise;
a siloxane-(meth)acrylate co-polymer; and
siloxane tackifying resin;
disposing the curable composition on at least a portion of the first major surface of the substrate; and
curing the curable composition to form siloxane-based gel adhesive.
15. The method of claim 14 , wherein the siloxane-(meth)acrylate copolymer comprises the reaction product of a reaction mixture comprising:
at least one ethylenically unsaturated siloxane-containing macromer;
at least one alkyl (meth)acrylate monomer; and
an initiator.
16. The method of claim 15 , wherein the reaction mixture further comprises a reinforcing monomer selected from an acid-functional (meth)acrylate monomer or a base-functional (meth)acrylate monomer.
17. The method of claim 14 , wherein curable composition comprises:
63-80 parts by weight of at least one siloxane fluid with a viscosity of at least 1,000,000 centiPoise;
1-20 parts by weight of at least one siloxane-(meth)acrylate co-polymer; and
16-20 parts by weight of siloxane tackifying resin.
18. The method of claim 14 , wherein curing the curable composition comprises exposure to actinic radiation.
19. The method of claim 14 , wherein the curable composition further comprises a peroxide initiator, and wherein curing the curable composition comprises exposure to heat sufficient to activate the peroxide initiator.
20. A curable composition, comprising:
a siloxane fluid with a viscosity of at least 1,000,000 centiPoise;
a siloxane-(meth)acrylate co-polymer; and
siloxane tackifying resin, wherein the curable composition is curable to a siloxane gel adhesive comprising a siloxane-based crosslinked matrix and extractable siloxane fluid upon exposure to actinic radiation.
21. A curable composition, comprising:
a siloxane fluid with a viscosity of at least 1,000,000 centiPoise;
a siloxane-(meth)acrylate co-polymer;
siloxane tackifying resin; and
a peroxide initiator.