Carbon fiber composite material and process for producing the same

• US 8,808,605 B2
• Filed: 02/13/2009
• Issued: 08/19/2014
• Est. Priority Date: 04/09/2003
• Status: Active Grant

• Current Assignee: Hitachi Astemo Ltd. (Hitachi, Ltd.)
• Original Assignee: Nissin Kogyo Company Limited (Hitachi, Ltd.)
• Inventors: Noguchi, Toru, Fukazawa, Shigeru, Shimizu, Shuichi
• Primary Examiner(s): Johnson, Christina
• Assistant Examiner(s): LIU, XUE H
• Application Number:
  US12/379,174
• Publication Number:
  US 20090166918A1
• Time in Patent Office: 2,013 Days
• Field of Search: 264/333.13
• US Class Current: 264/349
• CPC Class Codes: B29C 48/40 using two or more parallel screws or at least two parallel non-intermeshing screws, e.g. twin screw extruders
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C08J 2321/00 Characterised by the use of unspecified rubbers
• CPC Class Codes: C08J 5/005 Reinforced macromolecular compounds with nanosized materials, e.g. nanoparticles, nanofibres, nanotubes, nanowires, nanorods or nanolayered materials
• CPC Class Codes: C08J 5/042 with carbon fibres
• CPC Class Codes: C08K 2201/011 Nanostructured additives
• CPC Class Codes: C08K 7/06 Elements
• CPC Class Codes: C08K 7/24 inorganic
• CPC Class Codes: C08L 21/00 Compositions of unspecified rubbers
• CPC Class Codes: Y10S 428/903 Microfiber, less than 100 micron diameter
• CPC Class Codes: Y10S 977/778 within specified host or matrix material, e.g. nanocomposite films
• CPC Class Codes: Y10S 977/783 Organic host/matrix, e.g. lipid
• CPC Class Codes: Y10T 428/249924 Noninterengaged fiber-containing paper-free web or sheet which is not of specified porosity
• CPC Class Codes: Y10T 428/24994 Fiber embedded in or on the surface of a polymeric matrix
• CPC Class Codes: Y10T 428/249945 Carbon or carbonaceous fiber
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber

Abstract

The present invention provides a carbon fiber composite material comprising an elastomer and a carbon nanofiber dispersed in the elastomer, wherein the elastomer has an unsaturated bond or a group, having affinity to the carbon nanofiber. Also disclosed is a process for producing the carbon fiber composite material.

Claims

1. A process for producing a carbon fiber composite material comprising:

selecting an uncrosslinked elastomer having a spin-spin relaxation time (T2n) of its network component of 100 to 3,000 μ

sec as measured under conditions of an observing nucleus of ¹H at 30°

C. by the Hahn-echo method using pulsed NMR technique; and

substantially uniformly dispersing a plurality of carbon nanofibers into the elastomer by shear force at a temperature of 0 to 50°

C. by an open-roll method using two rolls with a roll distance of 0.5 mm or less,

wherein the elastomer has an unsaturated bond or a group, having affinity to the carbon nanofiber.

2. The process for producing a carbon fiber composite material according to claim 1, wherein the elastomer has a weight average molecular weight of 5,000 to 5,000,000.

3. The process for producing a carbon fiber composite material according to claim 1, wherein the elastomer has, in at least one of its main chain, side chains and terminal chains, at least one member selected from the group consisting of a double bond, a triple bond, a carbonyl group, a carboxyl group, a hydroxyl group, an amino group, a nitrile group, a ketone group, an amide group, an epoxy group, an ester group, a vinyl group, a halogen group, a urethane group, a biuret group, an allophanate group, and a urea group.

4. The process for producing a carbon fiber composite material according to claim 1, wherein the elastomer in the composite material is one of natural rubber (NR) and nitrile rubber (NBR).

5. The process for producing a carbon fiber composite material according to claim 1, wherein the carbon nanofibers have an average diameter of 0.5 to 500 nm.

6. The process for producing a carbon fiber composite material according to claim 1, wherein a surface velocity ratio of the two rolls is from 1.05 to 3.00.

7. The process for producing a carbon fiber composite material according to claim 1, further comprising crosslinking the elastomer in the composite material after the dispersion of the plurality of carbon nanofibers into the elastomer.

8. The process for producing a carbon fiber composite material according to claim 1, wherein substantially uniform dispersion of the plurality of nanofibers includes:

separating aggregations of nanofibers; and

preventing reaggregation of nanofibers,

wherein the non-aggregated nanofibers in the final carbon fiber composite material are homogenously dispersed throughout the elastomer.

9. A process for producing a carbon fiber composite material comprising:

selecting an uncrosslinked elastomer having a spin-spin relaxation time (T2n) of its network component of 100 to 3,000 μ

sec as measured under conditions of an observing nucleus of ¹H at 30°

C. by the Hahn-echo method using pulsed NMR technique;

substantially uniformly dispersing a plurality of carbon nanofibers into the elastomer by shear force, wherein the elastomer has an unsaturated bond or a group, having affinity to the carbon nanofiber;

ensuring that the resulting carbon fiber composite material in an uncrosslinked form has a first spin-spin relaxation time (T2n) of 100 to 3,000 μ

sec, and a second spin-spin relaxation time (T2nn) that is absent or 1,000 to 10,000 μ

sec, as measured under conditions of an observing nucleus of ¹H at 150°

C. by the Hahn-echo method using pulsed NMR technique; and

ensuring that a fraction (fnn) of components having the second spin-spin relaxation time, as compared to the first spin-spin relaxation time, is less than 0.2.

10. A process for producing a carbon fiber composite material comprising:

selecting an elastomer (1) in an uncrosslinked form having a spin-spin relaxation time (T2n) of its network component of 100 to 3,000 μ

sec as measured under conditions of an observing nucleus of ¹H at 30°

C. by the Hahn-echo method using pulsed NMR technique and (2) having an unsaturated bond or a group with an affinity to a carbon nanofiber;

dispersing a plurality of the carbon nanofibers into the elastomer; and

obtaining a carbon fiber composite material in an uncrosslinked form that has a first spin-spin relaxation time (T2n) of 100 to 3,000 μ

sec, a second spin-spin relaxation time (T2nn) that is absent or 1,000 to 10,000 μ

sec, as measured under conditions of an observing nucleus of ¹H at 150°

C. by the Hahn-echo method using pulsed NMR technique and a fraction (fnn) of components having the second spin-spin relaxation time, as compared to the first spin-spin relaxation time, of less than 0.2.