Method of manufacturing thin film, substrate having thin film, electron emission material, method of manufacturing electron emission material, and electron emission device

• US 20060214560A1
• Filed: 11/21/2005
• Published: 09/28/2006
• Est. Priority Date: 11/22/2004
• Status: Active Grant

• Current Assignee: Hitachi Astemo Ltd. (Hitachi, Ltd.)
• Original Assignee: Nissin Kogyo Company Limited (Hitachi, Ltd.)
• Inventors: Noguchi, Toru, Magario, Akira
• Granted Patent: US 7,927,169 B2
• Time in Patent Office: Days
• US Class Current: 313/498
• CPC Class Codes: B29C 43/24 Calendering
• CPC Class Codes: B29K 2105/162 Nanoparticles
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• 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: C08K 2201/011 Nanostructured additives
• CPC Class Codes: C08K 3/041 Carbon nanotubes
• CPC Class Codes: C08L 9/06 Copolymers with styrene
• CPC Class Codes: C09D 107/00 Coating compositions based on natural rubber
• CPC Class Codes: C09D 109/06 Copolymers with styrene
• CPC Class Codes: C09D 123/16 Elastomeric ethene-propene or ethene-propene-diene copolymers, e.g. EPR and EPDM rubbers
• CPC Class Codes: C09D 7/62 modified by treatment with other compounds
• CPC Class Codes: C09D 7/67 Particle size smaller than 100 nm
• CPC Class Codes: C09D 7/68 Particle size between 100-1000 nm
• CPC Class Codes: C09D 7/70 characterised by shape, e.g. fibres, flakes or microspheres
• CPC Class Codes: H01J 1/304 Field-emissive cathodes
• CPC Class Codes: H01J 2201/30469 Carbon nanotubes (CNTs)
• CPC Class Codes: H01J 31/123 Flat display tubes
• CPC Class Codes: H01J 61/0675 characterised by the material of the electrode
• CPC Class Codes: H01J 61/0735 : characterised by the material of the electrode
• CPC Class Codes: H01J 63/02 : Details, e.g. electrode, gas filling, shape of vessel
• CPC Class Codes: H01J 9/025 : of field emission cathodes
• CPC Class Codes: Y10T 428/249939 : Two or more layers
• CPC Class Codes: Y10T 428/2918 : including free carbon or carbide or therewith [not as steel]

Abstract

A method of manufacturing a thin film, including: mixing carbon nanofibers into an elastomer including an unsaturated bond or a group having affinity to the carbon nanofibers, and dispersing the carbon nanofibers by applying a shear force to obtain a carbon fiber composite material; mixing the carbon fiber composite material and a solvent to obtain a coating liquid; and applying the coating liquid to a substrate to form a thin film.

Claims

1. A method of manufacturing a thin film, the method comprising:

mixing carbon nanofibers into an elastomer including an unsaturated bond or a group having affinity to the carbon nanofibers, and dispersing the carbon nanofibers by applying a shear force to obtain a carbon fiber composite material;

mixing the carbon fiber composite material and a solvent to obtain a coating liquid; and

applying the coating liquid to a substrate to form a thin film.

2. The method of manufacturing a thin film as defined in claim 1,

wherein the elastomer has a molecular weight of 5,000 to 5,000,000.

3. The method of manufacturing a thin film as defined in claim 1,

wherein at least one of a main chain, a side chain, and a terminal chain of the elastomer includes at least one of a double bond, a triple bond, a-hydrogen, 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 method of manufacturing a thin film as defined in claim 1,

wherein a network component of the elastomer in an uncrosslinked form has a spin-spin relaxation time (T2n) measured at 30°

C. by a Hahn-echo method using a pulsed nuclear magnetic resonance (NMR) technique of 100 to 3,000 μ

sec.

5. The method of manufacturing a thin film as defined in claim 1,

wherein a network component of the elastomer in an crosslinked form has a spin-spin relaxation time (T2n) measured at 30°

C. by a Hahn-echo method using a pulsed nuclear magnetic resonance (NMR) technique of I 00 to 2,000 μ

sec.

6. The method of manufacturing a thin film as defined in claim 1,

wherein the carbon nanofibers have an average diameter of 0.5 to 500 nm.

7. The method of manufacturing a thin film as defined in claim 1,

wherein the step of obtaining the carbon fiber composite material includes tight milling a mixture of the carbon nanofibers and the elastomer by using an open-roll method with a roll interval of 0.5 mm or less.

8. The method of manufacturing a thin film as defined in claim 7,

wherein two rolls used in the open-roll method have a surface velocity ratio of 1.05 to 3.00.

9. The method of manufacturing a thin film as defined in claim 1,

wherein the step of obtaining the carbon fiber composite material is performed by an internal mixing method.

10. The method of manufacturing a thin film as defined in claim 1,

wherein the step of obtaining the carbon fiber composite material is performed by a multi-screw extrusion kneading method.

11. The method of manufacturing a thin film as defined in claim 1,

wherein the step of obtaining the carbon fiber composite material is performed at 0 to 50°

C.

12. The method of manufacturing a thin film as defined in claim 1,

wherein the step of forming the thin film is performed by a method selected from a spin coating method, a dipping method, a screen printing method, a spraying method, and an inkjet method.

13. A substrate having a thin film obtained by the method as defined in claim 1.

14. The substrate as defined in claim 13,

wherein the thin film has a g-value of a signal of an unpaired electron of carbon measured at 4.5°

K by using an electron spin resonance spectrometer of 2.000 or more and less than 2.002.

15. The substrate as defined in claim 14,

wherein the thin film has a line width of a signal of an unpaired electron of carbon measured at 4.5°

K by using an electron spin resonance spectrometer of 300 μ

T or more.

16. An electron emission material comprising a thin film obtained by the method as defined in claim 1.

19. An electron emission device comprising:

a cathode including the electron emission material as defined in claim 16;

and

an anode disposed at a specific interval from the cathode,

electrons being emitted from the electron emission material by applying voltage between the anode and the cathode.

17. An electron emission material comprising a carbon fiber composite material including an elastomer and carbon nanofibers dispersed in the elastomer.

20. An electron emission device comprising:

a cathode including the electron emission material as defined in claim 17;

and

an anode disposed at a specific interval from the cathode,

electrons being emitted from the electron emission material by applying voltage between the anode and the cathode.

18. A method of manufacturing an electron emission material, the method comprising:

mixing carbon nanofibers into an elastomer including an unsaturated bond or a group having affinity to the carbon nanofibers, and dispersing the carbon nanofibers by applying a shear force to obtain a carbon fiber composite material.