Structural adhesive materials

• US 8,840,813 B2
• Filed: 06/02/2008
• Issued: 09/23/2014
• Est. Priority Date: 06/01/2007
• Status: Active Grant

• Current Assignee: Hexcel Composites Limited (Hexcel Corporation)
• Original Assignee: Hexcel Composites Limited (Hexcel Corporation)
• Inventors: Aspin, Ian, Godot, Marine
• Primary Examiner(s): Pyon, Harold
• Assistant Examiner(s): Diggs, Tanisha
• Application Number:
  US12/601,826
• Publication Number:
  US 20100276645A1
• Time in Patent Office: 2,304 Days
• Field of Search: 252/500
• US Class Current: 252/512
• CPC Class Codes: C08K 2201/016 Additives defined by their aspect ratio
• CPC Class Codes: C08K 7/00 Use of ingredients characterised by shape
• CPC Class Codes: C08K 9/02 Ingredients treated with inorganic substances
• CPC Class Codes: C09J 11/00 Features of adhesives not provided for in group C09J9/00, e.g. additives
• CPC Class Codes: C09J 11/04 inorganic
• CPC Class Codes: C09J 2301/412 presence of microspheres
• CPC Class Codes: C09J 9/02 Electrically-conducting adhesives
• CPC Class Codes: H01B 1/20 Conductive material dispersed in non-conductive organic material organic macromolecular compounds or compositions C08
• CPC Class Codes: H01B 1/22 the conductive material comprising metals or alloys
• CPC Class Codes: H01B 1/24 the conductive material comprising carbon-silicon compounds, carbon or silicon
• CPC Class Codes: H05K 1/0259 Electrostatic discharge [ESD] protection
• CPC Class Codes: H05K 3/321 by conductive adhesives
• CPC Class Codes: H05K 9/0083 comprising electro-conductive non-fibrous particles embedded in an electrically insulating supporting structure, e.g. powder, flakes, whiskers H05K9/0086 takes precedence
• CPC Class Codes: Y10T 428/249933 Fiber embedded in or on the surface of a natural or synthetic rubber matrix
• CPC Class Codes: Y10T 428/249937 Fiber is precoated
• CPC Class Codes: Y10T 428/24994 Fiber embedded in or on the surface of a polymeric matrix
• CPC Class Codes: Y10T 428/249948 Fiber is precoated
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/31515 As intermediate layer

Abstract

An adhesive material comprising at least one adhesive polymeric resin, at least one low aspect ratio metal-coated additive, and at least one high aspect ratio metal-coated additive. There is additionally provided an adhesive material comprising at least one adhesive polymeric resin, and one of either; a) low aspect ratio metal-coated additives present in the range 0.2 wt. % to 30 wt. % of the adhesive material; or b) discrete high aspect ratio metal-coated additives present in the range 0.2 wt. % to 25 wt. % of the adhesive material.

Claims

1. An adhesive material that provides electrical conductance across a bondline having a thickness in the range between 50 microns and 400 microns, said adhesive material comprising:

a) an adhesive polymeric resin that is in the form of a bondline between two substrates wherein the thickness of said bondline is in the range between 50 microns and 400 microns and wherein said adhesive polymeric resin has a lap shear strength; and

b) low aspect ratio metal-coated additives disbursed in said adhesive polymeric resin; and

c) high aspect ratio metal-coated additives disbursed in said adhesive polymeric resin in an amount in the range of 2 weight percent to 15 weight percent so as to provide electrical conductance across said bondline and wherein the weight ratio of said high aspect ratio metal-coated additives to said low aspect ratio metal-coated additives is about 3 to 1, wherein the lap shear strength of said adhesive material is equal to or greater than the lap shear strength of said adhesive polymeric resin.

2. An adhesive material according to either claim 1 wherein the low aspect ratio metal-coated additives are selected from metal-coated particles, metal-coated spheres, metal-coated dendrites, metal-coated beads, any other metal-coated three-dimensional bodies, or any combination thereof.

3. An adhesive material according to claim 1, wherein the low aspect ratio metal-coated additives comprise a core material which is completely or partially coated by at least one suitable metal.

4. An adhesive material according to claim 3, wherein the core material is formed from polymer, rubber, ceramic, glass, carbon, metal, metal alloy, mineral, or refractory products.

5. An adhesive material according to claim 3 wherein the core material is porous or hollow, or comprises a core-shell structure.

6. An adhesive material according to claim 1, wherein the high aspect ratio metal-coated additives are selected from metal-coated particles, metal-coated flakes, metal-coated rods, metal-coated nanofibres, any other metal coated three-dimensional bodies, or any combination thereof.

7. An adhesive material according to claim 1, wherein the high aspect ratio metal-coated additives comprise a core material which is completely or partially coated by at least one suitable metal.

8. An adhesive material according to claim 7, wherein the core material is selected from polymer, rubber, ceramic, glass, carbon, metal, metal alloy, mineral, carbon nanotubes, and carbon nanofibres.

9. An adhesive material according to claim 1, wherein the metal coating for the low aspect ratio is selected from silver, gold, nickel, copper, tin, aluminium, platinum, palladium, bronze, brass, pewter, cupronickel, and duralumin.

10. An adhesive material according to claim 9, wherein the electrical resistivity of the metal coating is less than 3×

10<sup>−

5</sup> Ω

m.

11. An adhesive material according to claim 1, wherein the adhesive polymeric resin of the adhesive material is a thermoset or thermoplastic resin.

12. An adhesive material according to claim 1, wherein the adhesive material further comprises metallic or non-metallic particles.

13. An adhesive material according to claim 12, wherein the metallic particles are formed from silver, gold, nickel, copper, tin, aluminium, platinum, palladium, bronze, brass, sterling silver, pewter, cupronickel, or duralumin.

14. An adhesive material according to claim 12, wherein the non-metallic particles are selected from any of the following, either alone or in combination;

graphite flakes, graphite powders, graphite particles, graphene sheets, carbon nanotubes, carbon nanofibres, fullerenes, carbon black, intrinsically conducting polymers, or charge transfer complexes.

15. An adhesive material according to claim 1, wherein the adhesive material comprises at least one carrier.

16. An adhesive material according to claim 1, wherein the adhesive material comprises at least one curing agent.

17. An adhesive material according to claim 1, wherein the adhesive material comprises additional ingredients selected from flexibilisers, toughening particles/agents, additional accelerators, core shell rubbers, flame retardants, wetting agents, expanding and blowing agents, pigments/dyes, flame retardants, plasticisers, UV absorbers, anti-fungal compounds, fillers, viscosity modifiers/flow control agents, tackifiers, stabilisers, and inhibitors.

18. An adhesive material according to claim 1 wherein the bond line thickness is between 90 microns and 110 microns.

19. An adhesive material according to claim 1 wherein said low aspect ratio metal-coated additives are metal-coated beads and said high aspect ratio metal-coated additives are metal-coated fibers.

20. An adhesive material according to claim 19 wherein said low aspect ratio metal-coated additives have a sizes in the range of 10 to 40 microns and wherein said high aspect ratio metal-coated additives have lengths in the range of 150 to 300 microns.