Acrylic emulsion adhesives
Methods of forming acrylate polymers using emulsion polymerization techniques are described. The resulting acrylate polymers exhibit characteristics enabling their use in adhesives and replacing acrylic polymers formed by solvent-based polymerization methods. Various polymers and adhesives utilizing such polymers are also described.
1. A polymer emulsion composition comprising:
an acrylic block copolymer including a surfactant copolymerized with the acrylic block copolymer, the surfactant being chemically bound to the polymer chain;
the acrylic copolymer including a first segment of controlled molecular weight and position and a second segment of controlled molecular weight and position;
the first segment including a monomer having a functional group selected from the group consisting of a self reactive functional group, a reactive functional group, and combinations thereof.
2. The composition of claim 1 wherein the second segment is non-reactive with the functional group of the first segment.
3. The composition of claim 1 wherein the second segment does not contain a crosslinkable functional group.
4. The composition of claim 1 wherein the second segment includes a monomer having a reactive functional group.
5. The composition of claim 4 wherein the functional groups of the second segment are capable of undergoing crosslinking reactions while remaining reactive with each other.
6. The composition of claim 4 wherein the second segment is non-reactive with the functional group of the first segment.
7. The composition of claim 4 wherein the reactive functional groups are spaced apart along the length of the polymer chain.
8. The composition of claim 1 wherein the functional groups of the first segment are capable of undergoing crosslinking reactions while remaining reactive with each other.
9. The composition of claim 1 wherein the first segment and the second segment are positioned adjacent to the polymer chain ends.
10. The composition of claim 1 comprising two first segments and one second segment.
11. The composition of claim 10 wherein the first segments are positioned on either side of the second segment on the polymer chain.
12. The composition of claim 1 wherein the first segment and the second segment are miscible before cure.
13. The composition of claim 1 wherein the composition is a single phase polymer at room temperature.
14. The composition of claim 1 wherein the composition is a single phase liquid polymer at room temperature.
15. The composition of claim 1 wherein the first segment and the second segment are immiscible before cure.
16. The composition of claim 1 wherein the composition is a phase separated polymer at room temperature.
17. The composition of claim 1 wherein the composition is a phase separated liquid polymer at room temperature.
18. The composition of claim 1 wherein the composition is a liquid polymer at room temperature.
19. The composition of claim 1 wherein the glass transition temperature of the composition is about 10° C. to about −115° C.
20. The composition of claim 1 wherein the glass transition temperature of the composition is about 0° C. to about −80° C.
21. The composition of claim 1 wherein the glass transition temperature of the composition is about −10° C. to about −40° C.
22. The composition of claim 1 wherein the self reactive functional group is selected from the group consisting of silanes, anhydrides, epoxies, alkoxymethylol, and cyclic ethers.
23. The composition of claim 22 wherein the self reactive functional group is an epoxy.
24. The composition of claim 1 wherein the reactive functional group is selected from the group consisting of acids, hydroxyls, amines, thiols, (meth)acrylates, benzophenone, acetophenone, acyl phosphine, thioxanthone, and derivatives of benzophenone, acetophenone, acyl phosphine, and thioxanthone.
25. The composition of claim 24 wherein the reactive functional group is an acid.
26. The composition of claim 1 further including a tackifier.
27. The composition of claim 26 wherein the tackifier is selected from the group consisting of a hydrocarbon resin, hydrogenated hydrocarbon resin, a fully hydrogenated hydrocarbon resin, a hydrogenated rosin ester, a fully hydrogenated rosin ester, and combinations thereof.
28. The composition of claim 26 wherein the tackifier is a hydrocarbon resin.
29. The composition of claim 1 wherein the copolymerizable surfactant is selected from the group consisting of allyl or vinyl substituted alkyl phenolethoxylates and their sulfates; block copolymers of polyethylene oxide, propylene oxide or butylene oxide with polymerizable end groups; allyl or vinyl substituted ethoxylated alcohols and their sulfates; maleate half esters of fatty alcohols; monoethanolamide ethoxylates of unsaturated fatty acids capable of undergoing autoxidative polymerization; allyl or vinyl polyalkylene glycol ethers; alkyl polyalkylene glycolether sulfates; functionalized monomer and surfactants; and combinations thereof.
30. The composition of claim 1 wherein the emulsion particles have a size within a range of from about 2,000 to about 10 nm.
31. The composition of claim 30 wherein the particles have a size within a range of from about 500 to about 10 nm.
32. The composition of claim 31 wherein the particles have a size within a range of from about 300 to about 10 nm.
33. The composition of claim 1 wherein the polymer has a number average molecular weight (Mn) of equal to or greater than two times the polymer's entanglement molecular weight (Me).
34. The composition of claim 1 wherein the polymer has a number average molecular weight (Mn) within a range of from about 500,000 to about 100,000 g/mol.
35. The composition of claim 34 wherein the polymer has a number average molecular weight (Mn) within a range of from about 250,000 to about 110,000 g/mol.
36. The composition of claim 35 wherein the polymer has a number average molecular weight (Mn) within a range of from about 200,000 to about 125,000 g/mol.
37. The composition of claim 36 wherein the polymer has a number average molecular weight (Mn) within a range of from about 170,000 to about 130,000 g/mol.
38. The composition of claim 1 wherein the polymer has a polydispersity of less than 4.0.
39. The composition of claim 38 wherein the polymer has a polydispersity of less than 3.0.
40. The composition of claim 39 wherein the polymer has a polydispersity of less than 2.5.
41. The composition of claim 40 wherein the polymer has a polydispersity of less than 2.0.
42. A pressure sensitive adhesive comprising:
the composition of claim 1 ; and
a crosslinking agent.
43. The adhesive of claim 42 wherein the glass transition temperature of the adhesive is about 10° C. to about −115° C.
44. The adhesive of claim 42 wherein the glass transition temperature of the composition is about 0° C. to about −80° C.
45. The adhesive of claim 42 wherein the glass transition temperature of the composition is about −10° C. to about −40° C.
46. The adhesive of claim 42 wherein the pressure sensitive adhesive polymer exhibits a delta opacity of less than 10%.
47. The adhesive of claim 46 wherein the pressure sensitive adhesive polymer exhibits a delta opacity of less than 6%.
48. The adhesive of claim 47 wherein the pressure sensitive adhesive polymer exhibits a delta opacity of less than 2%.