Adhesive blends, articles, and methods

• US 20040202879A1
• Filed: 04/11/2003
• Published: 10/14/2004
• Est. Priority Date: 04/11/2003
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Xia, Jianhui, Lu, Ying-Yuh
• Granted Patent: US 7,927,703 B2
• Time in Patent Office: Days
• US Class Current: 428/500
• CPC Class Codes: B32B 2307/7246 Water vapor barrier
• CPC Class Codes: B32B 2551/00 Optical elements
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/308 comprising acrylic (co)polymers
• CPC Class Codes: B32B 27/365 comprising polycarbonates
• CPC Class Codes: B32B 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C09J 133/00 Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
• CPC Class Codes: C09J 133/06 of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
• CPC Class Codes: C09J 201/02 characterised by the presence of specified groups , e.g. terminal or pendant functional groups
• CPC Class Codes: C09J 2433/00 Presence of (meth)acrylic polymer
• CPC Class Codes: C09J 7/10 without carriers
• CPC Class Codes: C09J 7/35 Heat-activated
• CPC Class Codes: Y10T 428/2804 Next to metal
• CPC Class Codes: Y10T 428/2848 Three or more layers
• CPC Class Codes: Y10T 428/2891 including addition polymer from alpha-beta unsaturated carboxylic acid [e.g., acrylic acid, methacrylic acid, etc.] Or derivative thereof
• CPC Class Codes: Y10T 428/31507 Of polycarbonate
• CPC Class Codes: Y10T 428/31855 Of addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31909 Next to second addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31938 Polymer of monoethylenically unsaturated hydrocarbon

Abstract

Described are adhesive compositions containing a mixture of a pressure sensitive adhesive, a high Tg polymer, and a crosslinker to form a compatibilized blend that is optically clear. Methods of using the adhesive compositions, and multilayer assemblies such as optical elements prepared using the adhesives, are also provided.

Claims

1. An adhesive composition comprising a blend of:

a majority of a pressure sensitive adhesive component comprising at least one polymer with an acid or base functionality,

a high Tg polymer with an weight average molecular weight greater than 100,000 comprising an acid or base functionality, and

a crosslinker;

wherein the functionality of the pressure sensitive adhesive component and the functionality of the high Tg polymer form an acid-base interaction when mixed.

2. The adhesive composition of claim 1 wherein after aging at 80°

C. and 90% relative humidity for 500 hours, the composition is optically clear on visual observation.

3. The adhesive composition of claim 1 wherein after aging at 80°

C. and 90% relative humidity for 500 hours, the composition has a luminous transmission greater than 90%, and a haze less than 2%.

4. The adhesive composition of claim 1 wherein the high Tg polymer has a glass transition temperature greater than 20°

C.

5. The adhesive composition of claim 4 wherein the high Tg polymer has a glass transition temperature greater than 50°

C.

6. The adhesive composition of claim 1 wherein the high Tg polymer comprises a monomer selected from the group consisting of vinyl esters, (meth)acrylamide, styrenes, (meth) acrylontriles, substituted styrenes, vinyl halides, vinyl propionate, (meth)acrylates, and mixtures thereof.

7. The adhesive composition of claim 1 wherein the high Tg polymer is a basic copolymer.

8. The adhesive composition of claim 1 wherein the pressure sensitive adhesive comprises a copolymer with an weight average molecular weight less than 800,000.

9. The adhesive composition of claim 1 wherein the pressure sensitive adhesive is formed from free-radically polymerizable monomers selected from the group of (meth)acrylates, vinyl monomers, and mixtures thereof.

10. The adhesive composition of claim 1 comprising a crosslinker selected from the group consisting of multifunctional aziridine, peroxides, benzophenones, triazines, monoethylenically unsaturated mono-, di-, and trialkoxy silane compounds, diacrylates, triacrylates, and tetraacrylates, isocyanates, epoxies, and mixtures thereof.

11. The adhesive composition of claim 1 wherein the acid-base interaction increases the miscibility of the mixture such that the domain size of the high Tg polymer is reduced to less than the wavelength of light.

12. The adhesive composition of claim 11 wherein the domain size of the high Tg polymer is less than 100 nm.

13. The adhesive composition of claim 12 wherein the domain size of the high Tg polymer is less than 50 nm.

14. The adhesive composition of claim 1 further comprising an additive.

15. The adhesive composition of claim 1 wherein the pressure sensitive adhesive component comprises from 70 to 90 percent based on the weight of the total composition.

16. The adhesive composition of claim 1 wherein the high Tg polymer comprises from 10 to 30 percent based on the total weight of the composition.

17. The adhesive composition of claim 1 wherein the adhesive composition is a pressure sensitive adhesive.

18. An article comprising the adhesive composition of claim 1 coated on at least one surface of a substrate.

19. The article of claim 18 wherein the substrate is selected from the group consisting of a release liner, a film, and a rigid material.

38. The adhesive composition of claim 1 wherein after aging at 80°

C. and 90% relative humidity for 500 hours, the composition is optically clear on visual observation.

39. The adhesive composition of claim 1 wherein after aging at 80°

C. and 90% relative humidity for 500 hours, the composition has a luminous transmission greater than 90%, and a haze less than 2%.

20. A multi-layer assembly coated with an adhesive composition comprising an a mixture of:

a majority of a pressure sensitive adhesive component comprising at least one polymer with an acid or base functionality,

a high Tg polymer with an weight average molecular weight greater than 100,000 comprising an acid or base functionality, and

a crosslinker;

wherein the functionality of the pressure sensitive adhesive component and the functionality of the high Tg polymer form an acid-base interaction when mixed;

wherein the adhesive composition is optically clear, and wherein the adhesive composition bonds at least two layers together.

21. The multilayer assembly of claim 20 wherein the layers are selected from the group consisting of release liner, a film, and a rigid material.

22. The multilayer assembly of claim 20 wherein the adhesive composition bonds a low moisture vapor transfer layer to an outgassing layer.

23. The multilayer assembly of claim 22 wherein the outgassing layer comprises a material selected from the group consisting of a polycarbonate and a poly(methyl methacrylate).

24. The multilayer assembly of claim 22 wherein after aging at 80°

C. and 90% relative humidity for 500 hours, the bond between the outgassing layer and the low moisture vapor transfer layer does not delaminate or bubble, and the optical product remains optically clear.

25. The multilayer assembly of claim 22 wherein the low moisture vapor transfer layer is selected from the group consisting of a metallized polymeric film, an infrared reflecting film and a multilayer optical film.

26. The multilayer assembly of claim 20 wherein the assembly comprises a conductive optical element comprising a rigid polycarbonate layer adhered with the adhesive to a surface of a polymeric film layer, an opposite surface of the polymeric film layer being coated with a conductive layer.

27. A method of preparing a multi-layer article, the method comprising

coating onto a substrate an adhesive composition comprising a mixture of:

a majority of a pressure sensitive adhesive component comprising at least one polymer comprising an acid or base functionality,

a high Tg polymer with an weight average molecular weight greater than 100,000 comprising an acid or base functionality, and

a crosslinker;

wherein the functionality of the pressure sensitive adhesive component and the functionality of the high Tg polymer form an acid-base interaction when mixed.

28. The method of claim 27 further comprising the step of laminating the adhesive coated substrate on a second substrate.

29. The method of claim 27, wherein the adhesive composition is in a solvent before coating on the substrate.

30. The method of claim 29, further comprising the step of drying the adhesive composition to remove the solvent.

31. The method of claim 27, wherein the adhesive composition is crosslinked after coating the adhesive composition on the substrate.

32. An adhesive composition comprising a blend of:

a majority of a pressure sensitive adhesive component comprising at least one polymer with an acid functionality,

a high Tg polymer comprising a base functionality imparted by an amide group, and

a crosslinker;

wherein the functionality of the pressure sensitive adhesive component and the functionality of the high Tg polymer form an acid-base interaction when mixed; and

wherein the pressure sensitive adhesive component is free of alkoxy (meth)acrylates.

33. The adhesive composition of claim 32 wherein after aging at 80°

C. and 90% relative humidity for 500 hours, the composition is optically clear on visual observation.

34. The adhesive composition of claim 32 wherein after aging at 80°

C. and 90% relative humidity for 500 hours, the composition has a luminous transmission greater than 90%, and a haze less than 2%.

35. The adhesive composition of claim 32 wherein the pressure sensitive adhesive component comprises a copolymer with an weight average molecular weight less than 600,000.

36. The adhesive composition of claim 32 wherein a high Tg polymer with an weight average molecular weight greater than 50,000.

37. An adhesive composition comprising a blend of:

a majority of a pressure sensitive adhesive component comprising at least one polymer with a base functionality,

a high Tg polymer comprising an acid functionality, and

a crosslinker;

wherein the functionality of the pressure sensitive adhesive component and the functionality of the high Tg polymer form an acid-base interaction when mixed.