CARBON FIBER COMPOSITE SHEET, USE THEREOF AS A HEAT CONDUCTOR AND PITCH-BASED CARBON FIBER WEB SHEET FOR USE IN THE SAME

• US 20090061193A1
• Filed: 04/14/2006
• Published: 03/05/2009
• Est. Priority Date: 04/19/2005
• Status: Abandoned Application

• Current Assignee: Teijin Limited
• Original Assignee: Teijin Limited
• Inventors: Hirata, Masumi, Ban, Tetsuo, Hara, Hiroshi
• Application Number:
  US11/912,086
• Publication Number:
  US 20090061193A1
• Time in Patent Office: Days
• US Class Current: 428/220
• CPC Class Codes: C08J 5/042 with carbon fibres
• CPC Class Codes: D01F 9/145 from pitch or distillation residues
• CPC Class Codes: D04H 3/007 Addition polymers
• CPC Class Codes: D04H 3/16 with bonds between thermoplastic filaments produced in association with filament formation, e.g. immediately following extrusion
• CPC Class Codes: D21H 13/50 Carbon fibres
• CPC Class Codes: H01L 23/367 Cooling facilitated by shape of device H01L23/38, H01L23/40, H01L23/42, H01L23/44, H01L23/46 take precedence
• CPC Class Codes: H01L 23/373 Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H05K 3/4641 having integrally laminated metal sheets or special power cores
• CPC Class Codes: Y10T 428/24994 Fiber embedded in or on the surface of a polymeric matrix
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles

Abstract

A carbon fiber composite sheet comprising a pitch-based carbon fiber web and a matrix resin, wherein

• • carbon fibers constituting the pitch-based carbon fiber web have a crystallite size in the hexagonal net plane direction of 5 nm or more and a thermal conductivity in the thickness direction of 1 W/(m·K) or more.

This carbon fiber composite sheet is used for radio shielding and heat conduction.

Claims

1. A carbon fiber composite sheet comprising a pitch-based carbon fiber web and a matrix resin, wherein

carbon fibers constituting the pitch-based carbon fiber web have a crystallite size in the hexagonal net plane direction of 5 nm or more and a thermal conductivity in the thickness direction of 1 W/m·

K or more.

2. The carbon fiber composite sheet according to claim 1, wherein the amount of the matrix resin is 10 to 80 vol % of the carbon fiber composite sheet.

3. The composite sheet according to claim 1, wherein carbon fibers constituting the pitch-based carbon fiber web have a fiber diameter of 1 to 20 μ

m and a fiber length of 0.01 to 1,000 mm.

4. The composite sheet according to claim 1, wherein the matrix resin is a thermoplastic resin or a thermoplastic elastomer resin.

5. The composite sheet according to claim 4, wherein the thermoplastic resin is selected from polycarbonate, polyethylene terephthalate, polyethylene-2,6-naphthalene dicarboxylate, polyamide, polypropylene, polyethylene, polyepoxy ether ketone, polyphenylene sulfide or copolymers of each of these polymers.

6. The composite sheet according to claim 4, wherein the thermoplastic elastomer resin is a polyester elastomer.

7. The composite sheet according to claim 6, wherein the polyester elastomer is a block copolymer composed of a hard segment and a soft segment.

8. The composite sheet according to claim 6 which does not break in a bending test which is made on a test sample having a length of 160 mm and a width of 10 mm with a rod having a diameter of 15 mm under a load of 100 gf for 1 minute.

9. The composite sheet according to claim 1 which is used for radio shielding.

10. The composite sheet according to claim 9 which reflects 1 to 10 GHz radio waves in the neighboring field at 10 dB or more.

11. The composite sheet according to claim 1 which is used as a heat conductor.

12. A radiator plate for electronic parts which is composed of the composite sheet of claim 11.

13. A heat exchanger which is composed of the composite sheet of claim 11.

14. A carbon fiber sheet for pitch-based carbon fiber webs for use in the carbon fiber composite sheet of claim 1, which has a content of pitch-based carbon fibers having a crystallite size in the hexagonal net plane direction of 5 nm or more of 80 wt % or more, a carbon content of 80 wt % or more, a thickness of 0.05 to 5 mm and a porosity of 50 to 90 vol %.

15. The carbon fiber sheet according to claim 14, wherein the pitch-based carbon fibers have an average fiber diameter of 1 to 20 μ

m, a ratio of the degree of filament diameter distribution to average fiber diameter of 0.05 to 0.2 and a fiber length of 1 to 15 mm.

16. The carbon fiber sheet according to claim 14, wherein the pitch-based carbon fibers have a true density of 1.5 to 2.5 g/cc and a thermal conductivity in the fiber axial direction of 200 W/(m·

K) or more.

17. The carbon fiber sheet according to claim 14 which has a thermal conductivity in the thickness direction of 3 W/(m·

K) or more.

20. A method of manufacturing a carbon fiber composite sheet, comprising impregnating the carbon fiber sheet of claim 14 with a matrix resin.

21. The method of manufacturing a composite sheet according to claim 20, wherein impregnation is carried out under vacuum and increased pressure.

18. A method of manufacturing a carbon fiber sheet for pitch-based carbon fiber webs, which comprises manufacturing wet non-woven cloth from pitch-based carbon fibers in the presence of a binder in accordance with a papermaking method to obtain a sheet having a carbon content of 80 wt % or more, a thickness of 0.05 to 5 mm and a porosity of 50 to 90 vol %.

19. The method of manufacturing a carbon fiber sheet according to claim 18, wherein the wet non-woven cloth obtained by using a binder resulting carbon residue of at least 1 wt % based on the amount of the binder in accordance with the papermaking method is baked at 1,300 to 3,000°

C. in an inert gas atmosphere.