Flexible, formable conductive films

• US 20050247470A1
• Filed: 08/15/2003
• Published: 11/10/2005
• Est. Priority Date: 08/17/2002
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Fleming, Robert J., Condo, Peter D., Bright, Clark I., Anderson, Edward J.
• Granted Patent: US 7,261,950 B2
• Time in Patent Office: Days
• US Class Current: 174/394
• CPC Class Codes: H05K 9/0094 being light-transmitting, e.g. transparent, translucent
• CPC Class Codes: Y10T 428/12396 Discontinuous surface component
• CPC Class Codes: Y10T 428/12569 Synthetic resin
• CPC Class Codes: Y10T 428/12896 Ag-base component
• CPC Class Codes: Y10T 428/13 Hollow or container type article [e.g., tube, vase, etc.]
• CPC Class Codes: Y10T 428/24967 Absolute thicknesses specified
• CPC Class Codes: Y10T 428/24975 No layer or component greater than 5 mils thick
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
• CPC Class Codes: Y10T 428/265 1 mil or less
• CPC Class Codes: Y10T 428/31678 Of metal
• CPC Class Codes: Y10T 428/31688 Next to aldehyde or ketone condensation product
• CPC Class Codes: Y10T 428/31692 Next to addition polymer from unsaturated monomers

Abstract

Electrically conductive films comprising a flexible support, an extensible metal or metal alloy layer, and a crosslinked polymeric protective layer have at least one permanently deformed curved region. The films can be light transmissive and can have regions of compound curvature, and the metal or metal alloy layer can be substantially continuous. The films have reduced susceptibility to fracture or corrosion compared to commercially available electromagnetic interference (EMI) shielding films.

Claims

1. A conductive film comprising a flexible support, an extensible metal or metal alloy layer, and a crosslinked polymeric protective layer, wherein the film has at least one permanently deformed curved region.

2. A film according to claim 1, wherein the metal or metal alloy layer is substantially continuous, and the at least one permanently deformed curved region is compound curved.

3. A film according to claim 2, wherein the film is light transmissive.

4. A film according to claim 1, wherein the metal or metal alloy layer comprises silver and the crosslinked polymeric layer comprises an acrylate polymer.

5. A film according to claim 1, comprising two or more metal or metal alloy layers.

6. A film according to claim 5, wherein the layers are separated by a crosslinked polymeric spacing layer and provide an infrared-rejecting Fabry-Perot stack.

7. A film according to claim 1, wherein an interface between the metal or metal alloy layer and an adjacent layer within the film has been subjected to an adhesion-enhancing treatment, or one or more adjacent layers within the film comprise an adhesion-enhancing adjuvant, whereby the corrosion resistance of the film is increased.

8. A film according to claim 1, having a length and an electromagnetic shielding capability that is retained when the film is strained in a tensile mode by 5% of its length.

9. A film according to claim 1, having a length and an electromagnetic shielding capability that is retained when the film is strained in a tensile mode by 10% of its length.

10. A film according to claim 1, having an electromagnetic shielding capability that is retained when the film is bent at a 45°

angle.

11. A film according to claim 1, that exhibits color-shifting behavior when viewed from different viewing angles.

12. A film according to claim 1, further comprising at least one planar region.

13. A film according to claim 1, further comprising a thermoplastic supplemental support.

14. An electrical device comprising the film of claim 1.

15. The device of claim 14, wherein the device is selected from the group consisting of a cell phone, a personal digital assistant, a computer, and combinations thereof.

16. The device of claim 14, wherein the device comprises a heater.

17. A method for forming an article comprising:

a) providing a preform comprising a thermoplastic support having a metal or metal alloy layer and a crosslinked polymeric protective layer;

b) molding, embossing, thermoforming or otherwise deforming the preform to provide a self-supporting article having at least one permanently deformed curved region.

18. A method according to claim 17, wherein the metal or metal alloy layer is substantially continuous, and the at least one permanently deformed curved region is compound curved.

19. A method according to claim 18, wherein the metal or metal alloy layer and the crosslinked polymeric protective layer are light transmissive.

20. A method according to claim 17, wherein the metal or metal alloy layer comprises silver and the crosslinked polymeric layer comprises an acrylate polymer.

21. A method according to claim 17, wherein the preform comprises two or more metal or metal alloy layers.

22. A method according to claim 17, wherein the deforming is carried out by vacuum molding.

23. A method according to claim 17, wherein the deforming is carried out by thermoforming.

24. A method according to claim 17, wherein the deforming is carried Currently Amended by embossing.

25. A method according to claim 17, wherein the formed article has a length and an electromagnetic shielding capability that is retained when the article is strained in a tensile mode by 5% of its length.

26. A method according to claim 17, wherein the formed article has an electromagnetic shielding capability that is retained when the article is bent at a 45°

angle.

27. A method according to claim 17, wherein the perform has a first surface resistivity, wherein the deforming strains the article in a tensile mode by at least 5% of its length, and wherein the formed article has a second surface resistivity that is not substantially degraded relative to the first surface conductivity.

28. A method according to claim 27, wherein the second surface resistivity is no more than two times the first surface resistivity.

29. A method according to claim 27, wherein the second surface resistivity is less than the first surface resistivity.

30. A method according to claim 19, wherein perform has a first amount of haze, wherein the deforming strains the article in a tensile mode by at least 5% of its length, and wherein the formed article has a second amount of haze that is not substantially degraded relative to the first amount of haze.

31. A method according to claim 30, wherein the first and second amounts of haze are both below 5%, 3%, or 2%.