Molded article

• US 6,440,593 B2
• Filed: 02/01/2001
• Issued: 08/27/2002
• Est. Priority Date: 02/16/2000
• Status: Expired due to Fees

• Current Assignee: University Of Massachusetts
• Original Assignee: University Of Massachusetts
• Inventors: Lucke, Robert, McCarthy, Stephen P., Ellison, Thomas M., Delusky, Arthur K.
• Primary Examiner(s): DIXON, MERRICK L
• Application Number:
  US09/775,416
• Publication Number:
  US 20010031349A1
• Time in Patent Office: 572 Days
• Field of Search: 428/34.5, 428/373, 428/388, 428/929, 428/930, 428/931, 428/923, 428/925, 428/293.7, 428/294.1, 428/294.4, 428/295.4, 428/332, 428/379, 428/374
• US Class Current: 428/294.1
• CPC Class Codes: B32B 27/20 using fillers, pigments, thixotroping agents
• CPC Class Codes: Y10S 428/923 Physical dimension
• CPC Class Codes: Y10S 428/925 Relative dimension specified
• CPC Class Codes: Y10S 428/931 Components of differing electric conductivity
• CPC Class Codes: Y10T 428/249924 Noninterengaged fiber-containing paper-free web or sheet which is not of specified porosity
• CPC Class Codes: Y10T 428/24993 Fiber is precoated
• 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 428/2931 Fibers or filaments nonconcentric [e.g., side-by-side or eccentric, etc.]
• CPC Class Codes: Y10T 428/294 including metal or compound thereof [excluding glass, ceramic and asbestos]

Abstract

A molded plastic article having improved electromagnetic interference (EMI) shielding properties. The article includes a plastic layer and an outer film layer over the plastic layer. The outer film layer has an inner surface adjacent to and bonded to the plastic layer and an outer surface opposed to the inner surface. The plastic layer and outer layer are electrically conductive. Preferably the outer layer has higher conductivity than the plastic layer.

Claims

1. A molded plastic article, which comprises:

a plastic layer;

an outer film layer over said plastic layer and forming a composite laminate therewith, said outer film layer having an inner surface adjacent to and bonded to said plastic layer, and an outer surface opposed to said inner surface;

wherein said plastic layer and said outer layer are electrically conductive to provide resistance to electromagnetic interference, and wherein the plastic layer has a higher resistivity than the outer layer.

2. Article according to claim 1, wherein the plastic layer and outer film layer include conductive material incorporated therein.

3. Article according to claim 1, wherein the conductivity of the plastic layer is provided by incorporating therein at least one of conductive fibers and conductive particles.

4. Article according to claim 1, Wherein the outer film layer includes at least one of the following conductive materials:

conductive fibers, conductive particles, metal foil, metal mesh, carbon fiber, metallized film, metallized fiber and woven conductive fabric.

5. Article according to claim 1, including a third layer bonded to said plastic layer on the side thereof opposed to said outer film layer.

6. Article according to claim 5, wherein said third layer is electrically conductive.

7. Article according to claim 5, wherein the conductivity of the third layer is provided by incorporating therein at least one of conductive fibers and conductive particles.

8. Article according to claim 3, wherein plastic layer includes carbon fibrils as conductive fibers, said fibrils having fiber lengths of from 1 to 10 microns.

9. Article according to claim 8, wherein the plastic layer includes 3-5% by weight of said carbon fibrils.

10. Article according to claim 1 wherein said article is compression molded.

11. Article according to claim 1, including a reinforcing layer between the outer film layer and plastic layer.

12. Article according to claim 1, wherein said outer film layer is colored.

13. Article according to claim 1, wherein said outer film layer is plastic.

14. Article according to claim 1, wherein said outer film layer has a colored topcoat.

15. Article according to claim 14, wherein said outer film has a clear coat on top of the colored topcoat.

16. Article according to claim 1, wherein the volume resistivity of the plastic layer ranges from 3×

10⁶ to 3×

10² ohm meters.

17. Article according to claim 1, wherein the surface resistance of the outer layer is from 10¹ to 10⁻

3 ohms/square.

18. Article according to claim 1, wherein the surface resistance of the outer layer is at most 10¹ ohms/square.

19. Article according to claim 1, wherein the volume resistivity of the plastic layer is at most 3×

10⁶ ohm meter.

20. Article according to claim 1, the surface resistance of the plastic layer is from 10⁹ to 10⁵ ohms per square.

21. Article according to claim 1, wherein the outer film layer is a laminate.