Pressure-sensitive adhesive compositions and constructions

• US 20040202814A1
• Filed: 04/08/2004
• Published: 10/14/2004
• Est. Priority Date: 04/10/2003
• Status: Active Grant

• Current Assignee: Morgan Adhesives Company (Amcor Plc)
• Original Assignee: Morgan Adhesives Company (Amcor Plc)
• Inventors: Smith, Timothy, Moeller, Scott Allen, McMaster, Gary A.
• Granted Patent: US 7,081,498 B2
• Time in Patent Office: Days
• US Class Current: 428/40.1
• CPC Class Codes: C08K 5/01 Hydrocarbons C08K5/0091 takes precedence
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C08L 2666/24 Graft or block copolymers according to groups C08L51/00, C08L53/00 or C08L55/02; Derivatives thereof
• CPC Class Codes: C09J 153/02 Vinyl aromatic monomers and conjugated dienes
• CPC Class Codes: C09J 7/387 Block-copolymers
• CPC Class Codes: Y10T 428/14 Layer or component removable to expose adhesive

Abstract

The present invention is directed to pressure-sensitive adhesive compositions and pressure-sensitive adhesive constructions fabricated using the pressure-sensitive adhesive compositions. The pressure-sensitive adhesive compositions comprise about 10 to about 40% of a styrene-isoprene block copolymer, about 5 to about 30% of a styrene-butadiene block copolymer, about 30 to about 65% of an aromatically modified tackifying resin, about 8 to about 30% of a plasticizing oil and optionally about 0.2 to about 2% of an antioxidant, wherein the percentages are based on the total weight of the composition.

Claims

1. A pressure-sensitive adhesive composition comprising:

a) about 10 to about 40 wt. % of a styrene-isoprene block copolymer;

b) about 5 to about 30 wt. % of a styrene-butadiene block copolymer;

c) about 30 to about 65 wt. % of an aromatically modified tackifying resin; and

,

d) about 8 to about 30 wt. % of a plasticizing oil.

2. The adhesive composition of claim 1 further comprising about 0.2 to about 2.0 wt. % of an antioxidant.

3. The adhesive composition of claim 2 wherein said antioxidant comprises a pre-blended antioxidant in a resin carrier.

4. The adhesive composition of claim 1 wherein said styrene-isoprene block copolymer comprises from about 13 to about 27 wt. % of said composition.

5. The adhesive composition of claim 4 wherein said styrene-isoprene block copolymer comprises about 5 to about 80% by weight styrene-isoprene diblock component.

6. The adhesive composition of claim 4 wherein said styrene-isoprene block copolymer comprises about 40 to about 60% by weight styrene-isoprene diblock component.

7. The adhesive composition of claim 1 wherein said styrene-butadiene block copolymer comprises from about 8 to about 25 wt. % of said composition.

8. The adhesive composition of claim 7 wherein said styrene-butadiene block copolymer comprises from about 20 to about 35 wt. % bound styrene.

9. The adhesive composition of claim 8 wherein said styrene-butadiene block copolymer comprises from about 15 to about 20 wt. % block styrene.

10. The adhesive composition of claim 1 wherein said styrene-butadiene block copolymer comprises from about 10 to about 18 wt. % of said composition.

11. The adhesive composition of claim 10 wherein said styrene-butadiene block copolymer comprises from about 20 to about 35 wt. % bound styrene.

12. The adhesive composition of claim 11 wherein said styrene-butadiene block copolymer comprises from about 15 to about 20 wt. % block styrene.

13. The adhesive composition of claim 12 further comprising about 0.2 to about 2.0 wt. % of an antioxidant.

14. The adhesive composition of claim 1 wherein said aromatically modified tackifying resin has a softening point above about 85°

C.

15. The adhesive composition of claim 14 wherein said aromatically modified tackifying resin comprises about 6 to about 35% by weight aromatic content.

16. The adhesive composition of claim 14 wherein said aromatically modified tackifying resin has a softening point above about 90°

C.

17. The adhesive composition of claim 1 wherein said aromatically modified tackifying resin comprises about 6 to about 35% by weight aromatic content.

18. The adhesive composition of claim 1 wherein said aromatically modified tackifying resin has a softening point above about 90°

C.

19. The adhesive composition of claim 1 wherein said aromatically modified tackifying resin comprises about 40 to about 52 wt. % of said composition.

20. The adhesive composition of claim 19 wherein said aromatically modified tackifying resin comprises about 6 to about 35% by weight aromatic content.

21. The adhesive composition of claim 19 wherein said aromatically modified tackifying resin has a softening point above about 85°

C.

22. The adhesive composition of claim 21 further comprising about 0.2 to about 2.0 wt. % of an antioxidant.

23. The adhesive composition of claim 1 wherein said plasticizing oil comprises about 16 to about 22 wt. % of said composition.

24. The adhesive composition of claim 1 wherein said composition expresses a single glass transition temperature.

25. The adhesive composition of claim 1 wherein said adhesive composition has a tangent δ

value of greater than 0.5 at all temperatures in the range of about −

20°

C. to about 100°

C.

26. The adhesive composition of claim 1 wherein said composition has a composite midblock glass transition temperature of about 258 Kelvin to about 288 Kelvin.

27. The adhesive composition of claim 26 wherein said composition has a composite midblock glass transition temperature of about 263 Kelvin to about 283 Kelvin.

28. The adhesive composition of claim 26 wherein said composition has a composite midblock glass transition temperature of about 268 Kelvin to about 282 Kelvin.

29. The adhesive composition of claim 1 wherein said composition has a loop tack adhesion value to high density polyethylene greater than about 0.5 psi at 35°

F.

30. The adhesive composition of claim 1 wherein said composition has a loop tack adhesion value to high density polyethylene greater than about 2.5 psi at 70°

F.

31. The adhesive composition of claim 1 wherein said composition has a loop tack adhesion value to corrugated paperboard greater than about 0.3 psi at 35°

F.

32. The adhesive composition of claim 1 wherein said composition has a loop tack adhesion value to corrugated paperboard greater than about 1.5 psi at 70°

F.

33. A hot-melt pressure-sensitive adhesive composition comprising:

a) about 10 to about 40 wt. % of a styrene-isoprene block copolymer having about 5 to about 80% by weight styrene-isoprene diblock component;

b) about 5 to about 30 wt. % of a styrene-butadiene block copolymer having from about 20 to about 35 wt. % bound styrene and about 15 to about 20 wt. % block styrene;

c) about 30 to about 65 wt. % of an aromatically modified tackifying resin having between about 6 to about 35% aromatic content and a softening point above about 85°

C.; and

d) about 8 to about 30 wt. % of a plasticizing oil, wherein said composition expresses a single glass transition temperature and has a tangent δ

value of greater than about 0.5 for all temperatures in the range of about −

20°

C. to about 100°

C.

34. The adhesive composition according to claim 33 wherein said styrene-isoprene block copolymer comprises about 13 to about 27 wt. % of said composition.

35. The adhesive composition according to claim 33 wherein said styrene-isoprene block copolymer comprises about 14 to about 22 wt. % of said composition.

36. The adhesive composition according to claim 33 wherein said styrene-butadiene block copolymer comprises about 8 to about 25 wt. % of said composition.

37. The adhesive composition according to claim 33 wherein said styrene-butadiene block copolymer comprises about 10 to about 18 wt. % of said composition.

38. The adhesive composition according to claim 33 wherein said aromatically modified tackifying resin comprises about 40 to about 52 wt. % of said composition.

39. The adhesive composition according to claim 33 wherein said aromatically modified tackifying resin comprises about 45 to about 52 wt. % of said composition.

40. The adhesive composition according to claim 33 wherein said composition has a composite midblock glass transition temperature of about 258 Kelvin to about 288 Kelvin.

41. The adhesive composition according to claim 40 wherein said composition has a composite midblock glass transition temperature of about 263 Kelvin to about 283 Kelvin.

42. The adhesive composition according to claim 40 wherein said composition has a composite midblock glass transition temperature of about 268 Kelvin to about 282 Kelvin.

43. The adhesive composition according to claim 33 further comprising about 0.2 to about 2.0 wt. % of an antioxidant.

44. A pressure-sensitive adhesive construction comprising:

a) a face stock; and

b) a pressure-sensitive adhesive layer coated on at least one surface of said face stock, said pressure-sensitive adhesive comprising;

i) about 10 to about 40 wt. % of a styrene-isoprene block copolymer;

ii) about 5 to about 30 wt. % of a styrene-butadiene block copolymer;

iii) about 30 to about 65 wt. % of an aromatically modified tackifying resin; and

,

iv) about 8 to about 30 wt. % of a plasticizing oil.

45. The pressure-sensitive adhesive construction of claim 44 further comprising a release layer in contact with said pressure-sensitive adhesive layer.

46. The pressure-sensitive adhesive construction of claim 44 wherein said styrene-isoprene block copolymer comprises about 40 to about 60% by weight styrene-isoprene diblock component.

47. The pressure-sensitive adhesive construction of claim 44 wherein said aromatically modified tackifying resin has a softening point of greater than about 85°

C.

48. The pressure-sensitive adhesive construction of claim 44 wherein said aromatically modified tackifying resin has a softening point of greater than about 90°

C.

49. The pressure-sensitive adhesive construction of claim 44 wherein said aromatically modified tackifying resin has between from about 6% to about 35% by weight aromatic content.

50. The pressure-sensitive adhesive construction of claim 44 wherein said pressure-sensitive adhesive comprises:

i) about 10 to about 40 wt. % of a styrene-isoprene block copolymer having about 5 to about 80% by weight styrene-isoprene diblock component;

ii) about 5 to about 30 wt. % of a styrene-butadiene block copolymer having from about 20 to about 35 wt. % bound styrene and about 15 to about 20 wt. % block styrene;

iii) about 30 to about 65 wt. % of an aromatically modified tackifying resin having between about 6 to about 35% aromatic content and a softening point above about 85°

C.;

iv) about 8 to about 30 wt. % of a plasticizing oil, and

v) about 0.2 to about 2.0 wt. % of an antioxidant,

wherein said pressure-sensitive adhesive expresses a single glass transition temperature and has a tangent δ

value of greater than about 0.5 for all temperatures in the range of about −

20°

C. to about 100°

C.

51. The pressure-sensitive adhesive construction of claim 50 further comprising a release layer in contact with said pressure-sensitive adhesive layer.

52. The pressure-sensitive adhesive construction of claim 50 wherein said styrene-isoprene block copolymer comprises about 40 to about 60% by weight styrene-isoprene diblock component.

53. The pressure-sensitive adhesive construction of claim 50 wherein said styrene-isoprene block copolymer comprises about 50 to about 58% by weight styrene-isoprene diblock component.

54. The pressure-sensitive adhesive construction of claim 50 wherein said aromatically modified tackifying resin has a softening point of greater than about 85°

C.

55. The pressure-sensitive adhesive construction of claim 50 wherein said aromatically modified tackifying resin has a softening point of greater than about 90°

C.