Acrylic hot melt adhesives
High durable polarized film comprising a radiation curable PSA layer for lamination in TFT/LCD applications have high humidity and heat resistance. In one embodiment, the adhesive comprises a UV curable acrylic polymer, a compatible tackifier, a multifunction unsaturated oligomer, and a long chain alkyl acrylate monomer.
1. A radiation curable hot melt adhesive composition comprising an acrylic polymer and a long chain alkyl acrylate monomer.
2. The composition of claim 1 further comprising a compatible tackifier.
3. The composition of claim 1 wherein said alkyl acrylate monomer is selected from the group consisting of lauryl acrylate, isodecylate acrylate and mixtures thereof.
4. The composition of claim 1 comprising a photoinitiator.
5. The composition of claim 4 wherein the photoinitiator is bound to said acrylic polymer.
6. The composition of claim 5 wherein the acrylic polymer comprises a C4 to C8 alkyl acrylate.
7. The composition of claim 6 wherein the UV curable acrylic polymer comprises 2-ethylhexyl acrylate.
8. The composition of claim 7 wherein the photoinitiator comprises a benzophenone group.
9. The composition of claim 1 further comprising a multifunctional unsaturated oligomer.
10. The composition of claim 5 comprising 1 to 20 wt % alkyl acrylate monomer, 0 to 30 wt % of a compatible tackifier, 0 to 15 wt % of a multifunctional unsaturated oligomer, 0 to 2 wt % of added photoinitiator and 0 to 2% of a stabilizer.
11. The composition of claim 1 which has been cured by UV irradiation.
12. An article of manufacture comprising the cured hot melt adhesive composition of claim 11 .
13. A polarized film comprising a UV cured pressure sensitive adhesive composition.
14. The polarized film of claim 13 wherein the adhesive composition was prepared by curing a composition comprising a UV curable acrylic polymer and a long chain alkyl acrylate monomer.
15. The polarized film of claim 14 wherein the composition further comprises a compatible tackifier and a multifunctional unsaturated oligomer.
16. The polarized film of claim 15 wherein the composition comprises a hydrogenated rosin ester tackifier having a softening point of about 105° C.
17. The polarized film of claim 16 wherein the composition comprises an alkyl acrylate monomer selected from the group consisting of lauryl acrylate, isodecylate acrylate and mixtures thereof.
18. The polarized film of claim 17 further comprising a release liner.
19. The polarized film of claim 13 wherein the adhesive is applied as a melt.
20. The polarized film of claim 13 wherein the adhesive is applied in the form of a solution.