Conductive releasable adhesive and method of making same

• US 5,262,229 A
• Filed: 11/04/1991
• Issued: 11/16/1993
• Est. Priority Date: 11/04/1991
• Status: Expired due to Term

• Current Assignee: Columbia Insurance Company (Berkshire Hathaway Incorporated)
• Original Assignee: United Technical Products, Inc.
• Inventors: Klein, William, Lampert, Bruce G.
• Primary Examiner(s): Davis, Jenna L.
• Application Number:
  US07/787,372
• Time in Patent Office: 743 Days
• Field of Search: 428/40, 428/261, 428/288, 428/290, 428/301, 428/344, 428/354, 428/356, 428/343, 428/922, 428/220, 524/424, 524/435
• US Class Current: 428/220
• CPC Class Codes: C08L 2666/54 Inorganic substances
• CPC Class Codes: C09J 133/08 Homopolymers or copolymers of acrylic acid esters
• CPC Class Codes: D04H 1/4242 Carbon fibres
• CPC Class Codes: D04H 1/4291 Olefin series
• CPC Class Codes: D04H 1/4334 Polyamides
• CPC Class Codes: D04H 1/43828 sheath-core
• CPC Class Codes: H01B 1/20 Conductive material dispersed in non-conductive organic material organic macromolecular compounds or compositions C08
• CPC Class Codes: H01B 1/24 the conductive material comprising carbon-silicon compounds, carbon or silicon
• CPC Class Codes: H05K 3/321 by conductive adhesives
• CPC Class Codes: Y10S 428/922 Static electricity metal bleed-off metallic stock
• CPC Class Codes: Y10T 428/2804 Next to metal
• CPC Class Codes: Y10T 428/2857 including metal or compound thereof or natural rubber

Abstract

A conductive releasable adhesive and method of making same for electrostatic discharge controlled surfaces in which a multiplicity of interlacing electrically conductive fibers is suspended in a releasable adhesional substance forming a conductive matrix throughout the volume of the adhesional substance for facilitating dissipation of electrical charges.

Claims

1. A conductive releasable adhesive for electrostatic discharge controlled surfaces comprising:

a spreadable, releasable adhesional substance for dispersion between an electrostatic discharge controlled surface and a support surface; and

a multiplicity of interlacing electrically conductive fibers suspended in said adhesional substance forming a conductive matrix throughout the volume of the adhesional substance for dissipating charges which come into contact with the electrostatic discharge controlled surface.

2. The adhesive of claim 1 in which said releasable adhesional substance is a pressure sensitive acrylic polymer aqueous emulsion.

3. The adhesive of claim 1 in which said fibers comprise from 0.1 to 10 percent of the adhesive by weight.

4. The adhesive of claim 1 in which fibers are inert with respect to said adhesional substance not adversely affecting the tackiness or adhesive strength of said adhesional substance.

5. The adhesive of claim 1 in which said fibers are acrylic fibers conductively coated with copper sulfide.

6. The adhesive of claim 1 in which said fibers are carbon coated nylon conductive fibers.

7. The adhesive of claim 1 in which said fibers are carbon coated acrylic conductive fibers.

8. The adhesive of claim 1 in which said fibers are carbon coated polypropylene conductive fibers.

9. The adhesive of claim 1 in which said fibers have a Denier value of between 0.5 and 25.

10. The adhesive of claim 1 in which said fibers have diameter of between 0.0005 to 0.0025 inches.

11. The adhesive of claim 1 in which said fibers have a length of between 0.5 to 15 mm.

12. The adhesive of claim 1 in which said conductive matrix has a maximum surface electrical resistance of 2×

10⁷ ohms.

13. A method of making a conductive releasable adhesive for electrostatic discharge controlled surfaces comprising:

providing a spreadable, releasable adhesional substance for releasably securing electrostatic discharge controlled surfaces to a support surface; and

mixing said adhesional substance with a multiplicity of conductive fibers to suspend said fibers in said adhesional substance forming a conductive matrix throughout the volume of the adhesional substance.

14. The method of claim 13 in which said releasable adhesional substance is a pressure sensitive acrylic polymer aqueous emulsion.

15. The method of claim 13 in which said fibers comprise from 0.1 to 10% of the adhesive by weight.

16. The method of claim 13 in which said fibers are acrylic fibers conductively coated with copper sulfide.

17. The method of claim 13 in which said fibers are carbon coated nylon conductive fibers.

18. The method of claim 13 in which said fibers are carbon coated acrylic conductive fibers.

19. The method of claim 13 in which said fibers are carbon coated polypropylene conductive fibers.

20. The method of claim 13 in which said fibers have a Denier value of between 0.5 and 25.

21. The method of claim 13 in which said fibers have a diameter of between 0.0005 to 0.0025 inches.

22. The method of claim 13 in which said fibers have a length between 0.5 to 15 mm.

23. The method of claim 13 in which said mixing is accomplished by means of a ribbon blender.

24. The method of claim 13 in which said fibers are inert with respect to said adhesional substance not adversely affecting the tackiness adhesive strength of said adhesional substance.