COMPOSITIONS COMPRISING AN ACRYLIC BLOCK COPOLYMER AND A UV-CURABLE COPOLYMER AND METHODS OF MAKING AND USING THE SAME

• US 20140066539A1
• Filed: 08/28/2013
• Published: 03/06/2014
• Est. Priority Date: 08/31/2012
• Status: Active Grant

• Current Assignee: BASF SE
• Original Assignee: BASF SE
• Inventors: Tobing, Singa D., Yigezu, Hiruy
• Granted Patent: US 9,334,423 B2
• Time in Patent Office: Days
• US Class Current: 522/46
• CPC Class Codes: C09J 153/00 Adhesives based on block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers

Abstract

Disclosed herein are compositions comprising an acrylic block copolymer and a UV-curable copolymer, wherein the composition is capable of being crosslinked by means of ultraviolet radiation. Also disclosed herein are methods of making the compositions disclosed herein, comprising providing an acrylic block copolymer, providing a UV-curable copolymer, heating the acrylic block copolymer, heating the UV-curable copolymer, and mixing them together to form a copolymer blend. The compositions and methods disclosed can be used, for instance, in pressure-sensitive adhesive applications including, but not limited to, labels, films, or tapes.

Claims

1. A composition comprising:

an acrylic block copolymer comprising the unit P(A)-P(B) composed of one polymer block P(A) and one polymer block P(B), wherein the one 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 copolymer derived from a (meth)acrylate monomer, the UV-curable copolymer being capable of being crosslinked by means of ultraviolet radiation; and

a photoinitiator,

wherein the composition is capable of being crosslinked by means of ultraviolet radiation.

2. The composition according to claim 1, wherein the photoinitiator is bonded to a monomer unit of the UV-curable copolymer.

3. The composition according to claim 2, wherein the (meth)acrylate monomer unit has a pendant benzophenone group bonded to it.

4. The composition according to claim 1, wherein the composition comprises a photoinitiator that is not bonded to the copolymer.

5. The composition according to claim 4, wherein the photoinitiator includes benzophenone.

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

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

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

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

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

11. 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.

12. The composition according to claim 11, wherein the monomer B includes from 60% by weight to 100% by weight of the alkyl (meth)acrylate.

13. The composition according to claim 11, wherein the monomer B includes butyl acrylate, 2 ethyl hexyl acrylate, or mixtures thereof.

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

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

16. 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.

17. 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.

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

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

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

21. A label, film, or tape comprising the pressure-sensitive adhesive of claim 20, 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.

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

providing an acrylic block copolymer comprising the unit P(A)-P(B) composed of 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 copolymer derived from a (meth)acrylate monomer, wherein the UV-curable copolymer is capable of being crosslinked by means of ultraviolet radiation;

providing a photoinitiator; and

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