LOW DENSITY LIGHTNING STRIKE PROTECTION FOR USE IN AIRPLANES

• US 20090227162A1
• Filed: 03/09/2007
• Published: 09/10/2009
• Est. Priority Date: 03/10/2006
• Status: Active Grant

• Current Assignee: Goodrich Corporation (Raytheon Technologies Corporation d/b/a RTX), ROHR Incorporated (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Goodrich Corporation (Raytheon Technologies Corporation d/b/a RTX), ROHR Incorporated (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Mazany, Anthony Michael, Young, Eloise, Hill, Valerie A., Kruckenberg, Teresa M., Chiou, Song
• Granted Patent: US 8,962,130 B2
• Time in Patent Office: Days
• US Class Current: 442/1
• CPC Class Codes: B64D 45/02 Lightning protectors; Static dischargers in general H01T
• CPC Class Codes: C09D 5/24 Electrically-conducting paints conductive materials H01B1/00
• CPC Class Codes: Y10S 977/773 Nanoparticle, i.e. structure having three dimensions of 100 nm or less
• CPC Class Codes: Y10S 977/775 Nanosized powder or flake, e.g. nanosized catalyst
• CPC Class Codes: Y10S 977/778 within specified host or matrix material, e.g. nanocomposite films
• CPC Class Codes: Y10S 977/785 Electrically insulating host material
• CPC Class Codes: Y10S 977/92 Detection of biochemical
• CPC Class Codes: Y10S 977/961 for textile or fabric treatment
• CPC Class Codes: Y10T 428/24994 Fiber embedded in or on the surface of a polymeric matrix
• CPC Class Codes: Y10T 428/268 Monolayer with structurally defined element
• CPC Class Codes: Y10T 428/2918 including free carbon or carbide or therewith [not as steel]
• CPC Class Codes: Y10T 442/10 Scrim [e.g., open net or mesh, gauze, loose or open weave or knit, etc.]
• CPC Class Codes: Y10T 442/2475 Coating or impregnation is electrical insulation-providing, -improving, or -increasing, or conductivity-reducing
• CPC Class Codes: Y10T 442/3187 Triaxially woven fabric

Abstract

Surface films, paints, or primers can be used in preparing aircraft structural composites that may be exposed to lightning strikes. Methods for making and using these films, paints or primers are also disclosed. The surface film can include a thermoset resin or polymer, e.g., an epoxy resin and/or a thermoplastic polymer, which can be cured, bonded, or painted on the composite structure. Low-density electrically conductive materials are disclosed, such as carbon nanofiber, copper powder, metal coated microspheres, metal-coated carbon nanotubes, single wall carbon nanotubes, graphite nanoplatelets and the like, that can be uniformly dispersed throughout or on the film. Low density conductive materials can include metal screens, optionally in combination with carbon nanofibers.

Claims

1. A film for providing a desired level of lightning strike protection to a composite or metal substrate comprising a polymeric film with a low density conductive material comprising nanoparticles dispersed throughout or on the surface film at a loading level and in a manner which provides the desired lightning strike protection.

2. The film of claim 1, wherein the low density conductive material is selected from the group consisting of metal powders, metal nanowires, metal screens, metal-coated microspheres, and the following nanoparticles with or without metal coating:

carbon nanofibers, single wall carbon nanotubes, double wall carbon nanotubes, multi-wall carbon nanotubes, graphene oxide, graphene nanoplatelets, graphite nanoplatelets, and mixtures thereof.

3. The film of claim 1, wherein the low density conductive material is a carbon nanotube yarn, wherein the yarn is woven, braided, or fiber placed.

4. The film of claim 1, wherein the low density conductive material is in the form of a paper or felt comprising single wall carbon nanotubes, double wall carbon nanotubes, multi-wall carbon nanotubes, graphene oxide, graphene nanoplatelets, graphite nanoplatelets with or without metal coatings, and mixtures thereof.

5. The film of claim 1, wherein the low density conductive material comprises chemically-modified materials selected from chemically-modified single wall carbon nanotubes, double wall carbon nanotubes, multi-wall carbon nanotubes, graphene oxide, graphene nanoplatelets, and graphite nanoplatelets, and mixtures thereof.

6. The film of claim 1, wherein the film comprises a supported or unsupported thermoset polymer at an areal density of between about 0.015 and about 0.050 lb/ft² (70 to 232 gsm).

7. The film of claim 6, wherein the thermoset polymer comprises a polymeric material selected from the group consisting of epoxies, phenolics, cyanates, bismaleimides, polyimides, and polyurethanes.

8. The film of claim 6, wherein the support is a scrim.

9. The film of claim 1, wherein the surface film comprises a supported or unsupported thermoplastic polymer at an areal density of between about 0.015 and about 0.050 lb/ft² (70 to 232 gsm).

10. The film of claim 9, wherein the thermoplastic polymer comprises a polymeric material selected from the group consisting of polyvinylidene fluorides, polyetherimides, polyetheretherketones, polyaryletherketones, polyphenylene sulfides, polyetherketoneketones, polyurethanes, polyamides, polysulfones, polyimides, liquid crystalline polyesters, polymethyl methacrylate, and combinations thereof.

11. The film of claim 1, wherein the surface film comprises a two-phase combination of thermoset and/or thermoplastic polymers at a combined areal density of between about 0.015 and about 0.050 lb/ft² (70 to 232 gsm).

12. The film of claim 1, wherein the film provides Zone 1A lightning strike protection.

15. A composite material comprising the film of claim 1 and one or more layers formed by the lay-up and curing of one or more pre-preg layers, wherein the film and one or more layers are bonded to an aircraft component.

13. A composite material for providing lightning strike protection comprising:

a) a surface film, and

b) a structural fabric or prepreg layer underlying and adhered to the surface film,

wherein a low density conductive material is added to or dispersed onto the structural fabric or prepreg layer at a loading level and in a manner which provides the desired lightning strike protection.

14. The composite material of claim 13, wherein the structural fabric or prepreg layer is in the form of a woven fabric, braided fiber, or tape.

18. The paint or primer of claim 13, wherein the free flowing low density conductive material is made from chemically modified single wall carbon nanotubes, double wall carbon nanotubes, multi-wall carbon nanotubes, graphene oxide, graphene nanoplatelets, and graphite nanoplatelets, and mixtures thereof.

16. A paint or primer comprising:

a thermoset and/or thermoplastic resin in an amount ranging from about 10 to about 90% by weight, a solvent or thinner in an amount of a range from about 0 to about 80% by weight, and a free flowing low-density conductive material comprising nanoparticles, wherein the low-density conductive material is present in an amount ranging from about 1 to about 60% by weight.

17. The paint or primer of claim 16, wherein the free flowing low density conductive material is selected from the group consisting of metal powders, metal nanowires, metal-coated microspheres, and the following nanoparticles with or without metal coating:

carbon nanofibers, single wall carbon nanotubes, double wall carbon nanotubes, multi-wall carbon nanotubes, graphene oxide, graphene nanoplatelets, and graphite nanoplatelets, and mixtures thereof.

19. A method for preparing a film suitable for use in a low density lightning strike protection composite material, comprising:

a) melting a thermoplastic polymer,

b) adding a low density conductive material comprising nanoparticles to the melted thermoplastic polymer such that the low density conductive material is mixed throughout the melted thermoplastic polymer,

c) forming the melted thermoplastic polymer of step b) into a film, and

d) allowing the film to cool.

20. The method of claim 19, wherein the low density conductive material is selected from the group consisting of metal powders, metal nanowires, metal screens, metal-coated microspheres, and the following nanoparticles with or without metal coating:

carbon nanofibers, single wall carbon nanotubes, double wall carbon nanotubes, multi-wall carbon nanotubes, graphene oxide, graphene nanoplatelets, graphite nanoplatelets, and mixtures thereof.

21. A method for preparing a film suitable for use in a low density lightning strike protection composite material, comprising:

a) providing a monomer or mixture of monomers suitable for forming a thermoset polymer,

b) adding a low density conductive material comprising nanoparticles to the monomer or mixture of monomers, such that the low density conductive material is substantially uniformly mixed throughout the monomer(s),

c) forming the monomer(s) of step b) into the thickness of a film, and

d) curing the monomer(s).

22. The method of claim 21, wherein the low density conductive material is selected from the group consisting of metal powders, metal nanowires, metal screens, metal-coated microspheres, and the following nanoparticles with or without metal coating:

carbon nanofibers, single wall carbon nanotubes, double wall carbon nanotubes, multi-wall carbon nanotubes, graphene oxide, graphene nanoplatelets, graphite nanoplatelets, and mixtures thereof.

23. A method for forming a low-density lightning strike protection composite material, comprising:

a) obtaining a paper or felt comprising one or more low density conductive materials comprising nanoparticles,

b) applying a monomer or mixture of monomers to the paper or felt,

c) applying the monomer-applied paper or felt from step b) to a suitable substrate, and

d) curing the monomer(s).

24. The method of claim 23, wherein the low density conductive material(s) are selected from the group consisting of metal powders, metal nanowires, metal screens, metal-coated microspheres, and the following nanoparticles with or without metal coating:

carbon nanofibers, single wall carbon nanotubes, double wall carbon nanotubes, multi-wall carbon nanotubes, graphene oxide, graphene nanoplatelets, graphite nanoplatelets, and mixtures thereof.

25. A method for forming a low-density lightning strike protection composite material, comprising:

a) obtaining a yarn or fabric comprising one or more low density conductive materials comprising nanoparticles,

b) applying a monomer or mixture of monomers to the yarn or fabric,

c) applying the monomer-applied yarn or fabric from step b) to a suitable substrate, and

d) curing the monomer(s).

26. The method of claim 25, wherein the low density conductive material is selected from the group consisting of metal powders, metal nanowires, metal screens, metal-coated microspheres, and the following nanoparticles with or without metal coating:

carbon nanofibers, single wall carbon nanotubes, double wall carbon nanotubes, multi-wall carbon nanotubes, graphene oxide, graphene nanoplatelets, graphite nanoplatelets, and mixtures thereof.