Carbon fiber composite material

Patent metadata

Field	Value
Publication number	US-9481770-B2
Application number	US-201314403677-A
Country	US
Kind code	B2
Filing date	May 15, 2013
Priority date	May 29, 2012
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

A carbon fiber composite material which includes a carbon fiber sheet as a reinforcing material and a thermoplastic resin as a matrix resin, the carbon fiber sheet exhibiting a work per areal weight of 1×10 −3 to 30×10 −3 [(N·mm)/(g/m 2 )] in a tensile test using a specimen having a width of 25 mm. The carbon fiber composite material exhibits excellent flowability in molding and ensures excellent moldability even when molded into a complicated shape. Further, the composite material can yield a molded product which has high mechanical properties with minimized dispersion, thus being suitable for press molding.

First claim

The invention claimed is:

1. A carbon fiber composite material comprising a carbon fiber sheet as a reinforcing material and a thermoplastic resin as a matrix resin, said carbon fiber sheet exhibiting a work per areal weight of 1×10 −3 to 30×10 −3 [(N·mm)/(g/m 2 )] in a tensile test using a specimen having a width of 25 mm.

2. The carbon fiber composite material according to claim 1 , wherein a slope after reaching the maximum load in a load [N/(g/m 2 )]×10 −3 -strain [%] curve obtained in said tensile test of said carbon fiber sheet is −0.1 to −0.01.

3. The carbon fiber composite material according to claim 1 , wherein a slope after applying an initial load in a load [N/(g/m 2 )]×10 −3 -strain [%] curve obtained in said tensile test of said carbon fiber sheet is 0.1 to 0.7.

4. The carbon fiber composite material according to claim 1 , wherein a fiber length of carbon fibers forming said carbon fiber sheet is 5 to 30 mm.

5. The carbon fiber composite material according to claim 1 , wherein said carbon fiber sheet is formed from a starting material of a sheet-like carbon fiber aggregate formed from carbon fiber bundles cut at a predetermined length and thermoplastic resin short fibers.

6. The carbon fiber composite material according to claim 5 , wherein a proportion Y, relative to the total weight of carbon fibers, of carbon fiber bundles for which Mn/(Ln×D) is 8.5×10 −1 (mg/mm 2 ) or more, is 30≦Y<90 (wt %), an average value X of Mn/Ln for said carbon fiber bundles is 1.1×10 −2 ≦8.1×10 −2 (mg/mm), and said Y satisfies Y≧100X+30, where Mn: weight of carbon fiber bundles, Ln: fiber length, D: fiber diameter.

7. The carbon fiber composite material according to claim 5 , wherein with respect to said carbon fiber bundles forming said carbon fiber sheet, a number average “x” of numbers of carbon fibers forming carbon fiber bundles each having a weight of 0.01 mg or more and a number of carbon fibers of 90 or more for forming each carbon fiber bundle is 90 to 1,000/bundle, and a standard deviation a of said numbers of carbon fibers forming said carbon fiber bundles is 50 to 500.

8. The carbon fiber composite material according to claim 5 , wherein a sizing agent is applied to said carbon fiber bundles.

9. The carbon fiber composite material according to claim 1 , wherein a coefficient of fluidity, represented as a ratio of an area after being pressed at conditions of predetermined temperature and pressure to an area before being pressed, is 170% or more.

10. A carbon fiber reinforced plastic press molded with a carbon fiber composite material according to claim 1 .

11. The carbon fiber composite material according to claim 2 , wherein a slope after applying an initial load in a load [N/(g/m 2 )]×10 −3 -strain [%] curve obtained in said tensile test of said carbon fiber sheet is 0.1 to 0.7.

12. The carbon fiber composite material according to claim 2 , wherein a fiber length of carbon fibers forming said carbon fiber sheet is 5 to 30 mm.

13. The carbon fiber composite material according to claim 3 , wherein a fiber length of carbon fibers forming said carbon fiber sheet is 5 to 30 mm.

14. The carbon fiber composite material according to claim 2 , wherein said carbon fiber sheet is formed from a starting material of a sheet-like carbon fiber aggregate formed from carbon fiber bundles cut at a predetermined length and thermoplastic resin short fibers.

15. The carbon fiber composite material according to claim 3 , wherein said carbon fiber sheet is formed from a starting material of a sheet-like carbon fiber aggregate formed from carbon fiber bundles cut at a predetermined length and thermoplastic resin short fibers.

16. The carbon fiber composite material according to claim 4 , wherein said carbon fiber sheet is formed from a starting material of a sheet-like carbon fiber aggregate formed from carbon fiber bundles cut at a predetermined length and thermoplastic resin short fibers.

17. The carbon fiber composite material according to claim 6 , wherein a sizing agent is applied to said carbon fiber bundles.

18. The carbon fiber composite material according to claim 7 , wherein a sizing agent is applied to said carbon fiber bundles.

Assignees

• Toray Industries

Inventors

• Naruse Yoshihiro
• Miyoshi Katsuhiro
• Shimada Takashi
• Hashimoto Takafumi
• Ohara Tetsuya

Classifications

• B32B2250/05

  5 or more layers · CPC title

• B32B2260/046

  Synthetic resin · CPC title

• B32B2262/106

  Carbon fibres, e.g. graphite fibres · CPC title

• C08J5/042

  with carbon fibres · CPC title

• C08J5/06 Primary

  using pretreated fibrous materials · CPC title