Compositions comprising an acrylic block copolymer and a UV-curable copolymer and methods of making and using the same

1. A composition comprising:

an acrylic block copolymer comprising a polymer block P(A) and a polymer block P(B), wherein the polymer block P(A) represents a homopolymer or copolymer block derived from monomer A, the polymer block P(A) having a measured glass transition temperature of 50° C. to 200° C.; wherein the polymer block P(B) represents a homopolymer or copolymer block derived from monomer B, the polymer block P(B) having a measured glass transition temperature of −100° C. to 10° C.; and wherein the polymer blocks P(A) and P(B) are not homogenously miscible with one another; and

a UV-curable, non-block copolymer derived from a (meth)acrylate monomer, the UV-curable copolymer comprising a photoinitiator bonded to a monomer unit of the UV-curable, non-block copolymer, said UV-curable, non-block copolymer being capable of being crosslinked by means of ultraviolet radiation.

2. The composition according to claim 1 , wherein a (meth)acrylate monomer unit in the UV-curable, non-block copolymer has a pendant benzophenone group bonded to it.

3. The composition according to claim 1 , wherein the acrylic block copolymer includes a diblock copolymer.

4. The composition according to claim 1 , wherein the acrylic block copolymer includes a triblock copolymer.

5. The composition according to claim 1 , wherein the acrylic block copolymer comprises the unit P(A)-P(B)-P(A).

6. The composition according to claim 1 , wherein the monomer A includes methyl methacrylate, a vinyl aromatic, or a mixture thereof.

7. The composition according to claim 1 , wherein the monomer A includes styrene.

8. The composition according to claim 1 , wherein the monomer B includes an alkyl (meth)acrylate wherein the alkyl group has 4 to 9 carbon atoms.

9. The composition according to claim 8 , wherein the monomer B includes from 60% by weight to 100% by weight of the alkyl (meth)acrylate.

10. The composition according to claim 8 , wherein the monomer B includes butyl acrylate, 2 ethyl hexyl acrylate, or mixtures thereof.

11. The composition according to claim 1 , wherein the monomer B includes a vinyl monomer.

12. The composition according to claim 1 , wherein the monomer B includes from 0% by weight to 25% by weight of vinyl monomer.

13. The composition according to claim 1 , wherein the monomer B includes an acrylic monomer having a functional group that is susceptible to undergo crosslinking by UV initiation of the photoinitiator.

14. The composition according to claim 1 , wherein the polymer block P(A) is present in the acrylic block copolymer in an amount of from 5% by weight to 50% by weight, and the polymer block P(B) is present in the acrylic block copolymer in an amount of from 50% by weight to 95% by weight.

15. The composition according to claim 1 , wherein the (meth)acrylate monomer in the UV-curable, non-block copolymer includes a (meth)acrylate monomer selected from the group consisting of butyl acrylate, 2 ethylhexyl acrylate, and mixtures thereof.

16. The composition according to claim 1 , wherein the acrylic block copolymer includes a diblock copolymer and a triblock copolymer.

17. A pressure-sensitive adhesive, comprising the composition of claim 1 .

18. A label, film, or tape comprising the pressure-sensitive adhesive of claim 17 , wherein after adherence the adhesive can be removed without leaving a residue on a stainless steel panel at a peel force of from 0.5 lb/in to 2 lb/in.

19. A method of making a copolymer blend, comprising:

providing an acrylic block copolymer comprising a polymer block P(A) and a polymer block P(B), wherein the polymer block P(A) represents a homopolymer or copolymer block derived from monomer A, the polymer block P(A) having a measured glass transition temperature of 50° C. to 200° C., wherein the polymer block P(B) represents a homopolymer or copolymer block derived from monomer B, the polymer block P(B) having a measured glass transition temperature of −100° C. to 10° C., and wherein the polymer blocks P(A) and P(B) are not homogenously miscible with one another;

providing a UV-curable, non-block copolymer derived from a (meth)acrylate monomer, wherein the UV-curable copolymer comprising a photoinitiator bonded to a monomer unit of the UV-curable, non-block copolymer, said UV curable, non-block copolymer is capable of being crosslinked by means of ultraviolet radiation; and

melt mixing the UV-curable, non-block copolymer and the acrylic block copolymer at a temperature sufficient to soften the UV-curable, non-block copolymer and the acrylic block copolymer to produce a copolymer blend.

20. The composition according to claim 1 , wherein the composition comprises 15 to 50 parts by weight of the acrylic block copolymer, 15 to 30 parts by weight of a tackifier, and 40 to 75 parts by weight of the UV-curable, non-block copolymer.

21. The composition according to claim 1 , wherein the UV-curable, non-block copolymer includes a photoinitiator incorporated in the polymer backbone selected from 4-acryloxyloxy benzophenone, 4-acryloxyethoxy benzophenone, 4-acryloxybutoxy benzophenone, and 4-acryloxyhexoxy benzophenone.

22. The method of claim 19 , wherein melt mixing the UV-curable, non-block copolymer and the acrylic block copolymer comprises:

heating the acrylic block copolymer at a temperature sufficient to soften the acrylic block copolymer;

agitating the softened acrylic block copolymer; and

adding the UV-curable, non-block copolymer to the agitated, softened acrylic block copolymer, thereby producing a copolymer blend.