Composite materials

Patent metadata

Field	Value
Publication number	US-9296869-B2
Application number	US-201013379025-A
Country	US
Kind code	B2
Filing date	Jun 25, 2010
Priority date	Jun 26, 2009
Publication date	Mar 29, 2016
Grant date	Mar 29, 2016

Abstract

A prepreg comprising a structural layer of packed unidirectional conductive fibres comprising thermosetting resin in the interstices, and a first outer layer of resin comprising thermosetting resin, and being essentially free of unidirectional conductive fibres, which when cured under elevated temperature, produces a cured composite material comprising a cured structural layer of packed unidirectional conductive fibres and a first outer layer of cured resin comprising unidirectional conductive fibres dispersed within.

First claim

The invention claimed is:

1. A prepreg comprising a structural layer comprising a population of unidirectional conductive fibres having a cross-sectional diameter of from 3 to 12 microns and thermosetting resin, said prepreg further comprising a first outer layer of resin comprising thermosetting resin, said first outer layer of resin being located adjacent to a first surface of said structural layer and being essentially free of unidirectional conductive fibres, said structural layer comprising a first outer region located adjacent to said first outer layer of resin, said first outer region comprising a first portion of said population of unidirectional conductive fibres wherein the unidirectional conductive fibres in said first portion have been disrupted so as to form disrupted interstices located therebetween, said disrupted interstices having a disrupted size, said structural layer comprising a first inner region located adjacent to said first outer region, said first inner region comprising a second portion of said population of unidirectional conductive fibres wherein the unidirectional conductive fibres in said second portion have not been disrupted, said population of unidirectional conductive fibres in said second portion having non-disrupted interstices located therebetween which have a non-disrupted size wherein the non-disrupted size of said non-disrupted interstices is smaller than the disrupted size of said disrupted interstices, said prepreg comprising a first particulate material wherein the ratio of the mean particle size of the first particulate material to the mean diameter of the unidirectional conductive fibres is from 1.5:1 to 1:1.5 and wherein the size of said first particulate material is sufficiently small so that said first particulate material is located in said disrupted interstices and wherein the size of said first particulate material is sufficiently large so that said first particulate material is not located in said non-disrupted interstices, and wherein the amount of first particulate material located in said disrupted interstices is from 5 to 40 weight percent of the total amount of first particulate material in said prepreg and wherein said prepreg, when cured, produces a cured composite material wherein said first portion of disrupted unidirectional fibres migrates into said first outer layer of resin.

2. A prepreg according to claim 1 wherein said first particulate material has a sphericity of greater than 0.8.

3. A prepreg according to claim 1 , which comprises a second outer layer of resin which is located adjacent to a second surface of said structural layer that is opposite from said first outer layer of resin and wherein said second outer layer of resin is also essentially free of unidirectional conductive fibres and wherein said structural layer further comprises a second outer region located adjacent to said second outer layer of resin, said second outer region comprising a third portion of said population of unidirectional conductive fibres wherein the unidirectional conductive fibres in said third portion have been disrupted so as to form disrupted interstices located therebetween, said disrupted interstices having a disrupted size, said structural layer comprising a second inner region located adjacent to said second outer region, said second inner region comprising a fourth portion of said population of unidirectional conductive fibres wherein the unidirectional conductive fibres in said fourth portion have not been disrupted, said population of unidirectional conductive fibres in said fourth portion having non-disrupted interstices located therebetween which have a non-disrupted size wherein the non-disrupted size of said non-disrupted interstices in said fourth portion is smaller than the disrupted size of said disrupted interstices in said third portion, said prepreg comprising a second particulate material wherein the ratio of the mean particle size of the second particulate material to the mean diameter of the unidirectional conductive fibres is from 1.5:1 to 1:1.5 and wherein the size of said second particulate material is sufficiently small so that said second particulate material is located in said disrupted interstices of said third portion and wherein the size of said second particulate material is sufficiently large so that said second particulate material is not located in said non-disrupted interstices of said fourth portion, and wherein the amount of second particulate material located in said disrupted interstices of said third portion is from 5 to 40 weight percent of the total amount of second particulate material in said prepreg and wherein said prepreg, when cured, produces a cured composite material wherein said third portion of disrupted unidirectional fibres migrates into said second outer layer of resin.

4. A prepreg according to claim 3 , wherein said second particulate material consists of polyamide particles.

5. A cured composite laminate comprising a prepreg according to claim 3 that has been cured such that from 10 to 20% of the population of said unidirectional conducting fibres has migrated into said second outer layer of resin.

6. A prepreg according to claim 3 wherein said population of unidirectional conductive fibres have cross-sectional diameters 6 microns.

7. A prepreg according to claim 6 wherein said first and second particulate materials consist of polyamide particles having a nominal diameter of 8 microns.

8. A prepreg according to claim 7 wherein said first and second particulate materials consist of polyamide particles that have a sphericity of greater than 0.8.

9. A prepreg according to claim 1 , wherein the thermosetting resin in the structural layer is the same composition as the thermosetting resin in the first outer layer of resin.

10. A cured composite laminate comprising a prepreg according to claim 1 that has been cured such that from 10 to 20% of the population of said unidirectional conducting fibres has migrated into said first outer layer of resin.

11. A prepreg according to claim 1 , wherein said first particulate material consists of polyamide particles.

12. A prepreg according to claim 1 , wherein said unidirectional conductive fibers in said structural layer are carbon fibres.

13. A prepreg according to claim 1 wherein said population of unidirectional conductive fibres have cross-sectional diameters 6 microns.

14. A prepreg according to claim 13 wherein said first particulate material consists of polyamide particles having a nominal diameter of 8 microns.

15. A prepreg according to claim 14 wherein said first particulate material consists of polyamide particles that have a sphericity of greater than 0.8.

Assignees

• Ellis John
• Fisset Emille
• Tilbrook David
• Mackenzie Paul
• Hexcel Composites Ltd

Inventors

• Ellis John
• Fisset Emille
• Tilbrook David
• Mackenzie Paul

Classifications

• Y10T428/249942

  Fibers are aligned substantially parallel · CPC title

• B29K2995/0005

  Conductive · CPC title

• Y10T428/25

  Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles · CPC title

• B32B5/28

  impregnated with or embedded in a plastic substance {(not used)} · CPC title

• B29C70/882 Primary

  partly or totally electrically conductive, e.g. for EMI shielding (conductive floors or floor coverings H05F3/025; EMI shielding in general H05K9/00) · CPC title