JP5323974B2 - Graphite composite film and method for producing the same - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a graphite composite film used as a heat dissipation film and heat spreader material for electronic equipment, precision equipment and the like, and a method for producing the same, and more particularly to a strong graphite composite film and a method for producing the same. The graphite film of this invention can be used for an electronic material, a housing | casing, an aircraft member, etc., for example.

In recent years, semiconductor elements of electronic devices have been improved in performance while being reduced in size, and a material capable of diffusing heat in a small space and a small size is required. The graphite film that occupies an important position as such a material is lightweight and excellent in thermal conductivity. Such a graphite film has a highly developed layered graphite structure in the plane direction of the film, and has anisotropy in thermal conductivity and electrical conductivity based on the anisotropy of such a structure.
As a generally available method for producing a highly heat-conductive graphite film, there are an expanding method in which expanded graphite is rolled into a sheet, or a polymer pyrolysis method. In the polymer pyrolysis method in which a polymer film such as a polyimide film is heat-treated and rolled, a graphite film having high quality, strong bending resistance and high flexibility can be obtained. In addition, the graphite film thus prepared is very excellent in crystallinity, electrical conductivity, and thermal conductivity (Patent Document 1). Therefore, the use as a heat radiating member of electronic equipment is increasing.

  However, the graphite film has a problem that it is easily broken during handling and has low mechanical strength.

  On the other hand, in the field of electronic devices such as notebook computers, mobile phones, DVDs, etc., the transition from the conventional heavy, large size to light, thin, short size is rapidly progressing.

  As electronic devices become more compact, ICs and CPUs have become more sophisticated. As a result, the amount of heat generated per unit volume has increased, and the heat generation density of electronic devices has rapidly increased. For example, carbon fiber reinforced plastic (CFRP), which has been used for housings such as personal computers, has a thermal conductivity of 5 W / (m · K) or less, and laminated heating of carbon fiber prepregs. Since the thermal conductivity of the pressure-molded product is 50 W / (m · K) or less, there is a problem of low-temperature burns due to the heat of the casing. Furthermore, if the housing only has a high thermal conductivity, the heat generated from the IC or CPU can be spot-transmitted instantaneously from the housing facing the IC or CPU. Just because the body's thermal conductivity is high, it is even more likely to cause burns. In order to prevent such burns, in addition to the high thermal conductivity of the casing itself, the thermal conductivity in the surface direction of the casing is significantly higher than the thermal conductivity in the thickness direction of the casing, It is necessary to prevent a local temperature rise by instantly spreading the heat of the component not in the thickness direction of the housing but in the surface direction.

  For this reason, a casing formed by impregnating a graphite film into a resin, laminating a graphite prepreg, and heating and pressing is also known (Patent Document 2). Since such a casing uses a graphite sheet, the thermal conductivity is high and local heat can be diffused in the surface direction. However, since the casing prepared in this way is also composed only of the graphite film and the resin, the mechanical strength may not be sufficient.

JP 61-275116 A JP 2006-95935 A

  An object of the present invention is to solve the above-mentioned problems, and to provide a graphite composite material that is light in weight, excellent in mechanical strength, and excellent in thermal conductivity.

  The present invention includes the following inventions.

  (1) A reinforcing fiber layer is formed on at least one surface of a graphite film having a through hole, and the reinforcing fiber layer is obtained by impregnating a fiber with a thermosetting resin and / or a thermoplastic resin, and the thermosetting A graphite composite film in which a conductive resin and / or a thermoplastic resin fills the through hole.

  (2) A reinforcing fiber layer is formed on at least one surface of a graphite film having a through hole, and the reinforcing fiber layer is obtained by impregnating a fiber with a thermosetting resin and / or a thermoplastic resin, and the thermosetting A graphite composite film in which a functional resin and / or a thermoplastic resin penetrates into the opposite surface of the graphite film through the through hole.

  (3) A reinforcing fiber layer is formed on at least one surface of a graphite film having a through hole, and the reinforcing fiber layer is obtained by impregnating a fiber with a thermosetting resin and / or a thermoplastic resin. A graphite composite film obtained by laminating a reinforcing fiber layer and melting and laminating a resin.

  (4) The graphite composite film according to (3), wherein the lamination is performed using a hot press, a vacuum press, a laminator, or an autoclave.

  (5) The graphite composite film according to any one of (1) to (4), wherein the reinforcing fiber layer is obtained by impregnating a fiber with an epoxy resin.

  (6) The ratio of the said through-hole is a graphite composite film in any one of (1)-(5) which is 3 to 50% by surface area with respect to a graphite film seeing from a surface direction.

(7) In the graphite composite film,
a) The thickness of the graphite film is 3 μm or more and 500 μm or less,
b) The thickness of the reinforcing fiber layer is 10 μm or more and 300 μm or less. c) The ratio T _F / T _G of the thickness T _F of the reinforcing fiber layer and the thickness T _G of the graphite film is 0.1 or more and 20 or less ( The graphite composite film according to any one of 1) to (6).

  (8) The graphite film is polyimide, polyamide, polyoxadiazole, polybenzothiazole, polybenzobisthiazole, polybenzoxazole, polybenzobisoxazole, polyparaphenylene vinylene, polybenzimidazole, polybenzobisimidazole, and The graphite composite film according to any one of (1) to (7), which is obtained by heat treatment of at least one polymer selected from the group consisting of polythiazoles.

  (9) The graphite composite film according to any one of (1) to (8), wherein the graphite film has an MIT of 10,000 times or more, and further has a water absorption of 2% or less.

  (10) The reinforcing fiber layer is a reinforcing fiber layer made of at least one kind of fiber selected from the group consisting of carbon fiber, aramid fiber, glass fiber, synthetic fiber, natural fiber, and nylon (1) to (9 The graphite composite film according to any one of the above.

  (11) The graphite composite film according to any one of (1) to (10), wherein the reinforcing fiber layer is a reinforcing fiber layer in which the orientation of fibers is aligned in one direction.

  (12) The graphite composite film according to (11), wherein at least one reinforcing fiber layer is oriented in different directions in a graphite composite film having two or more reinforcing fiber layers in which the fibers are aligned in one direction. .

  (13) The graphite composite film according to any one of (1) to (12), wherein a thermal conductivity in a plane direction of the graphite composite film is 10 W / (m · K) or more.

  (14) The graphite composite film according to any one of (1) to (13), wherein the graphite composite film has a tensile strength of 300 MPa or more.

  (15) A graphite composite film having a step of bonding a reinforcing fiber layer impregnated with a thermosetting resin and / or a thermoplastic resin to a fiber and melting and laminating the resin on at least one surface of the graphite film having a through-hole. Production method.

  (16) The method for producing a graphite composite film according to 15, wherein the lamination is performed using a hot press, a vacuum press, a laminator, or an autoclave.

  (17) The method for producing a graphite composite film according to (15) or (16), wherein the graphite composite film is described in any one of (1) to (14).

  According to the present invention, a graphite composite material that is lightweight and excellent in mechanical strength can be obtained. In addition, a composite material having better thermal conductivity than conventional CFRP can be obtained.

  The graphite composite film of the present invention has a reinforcing fiber layer formed on at least one surface of the graphite film.

<Reinforcing fiber layer>
The reinforcing fiber layer here is a layer made of reinforcing fibers, and the strength of the composite material can be increased by using the fibers.
Examples of the reinforcing fiber of the present invention include carbon fiber, aramid fiber, glass fiber, synthetic fiber, natural fiber, and nylon. Since these fibers are excellent in mechanical strength, the strength of the graphite film can be reinforced by compounding with the graphite film. Further, when carbon fiber is used as the reinforcing fiber, a composite material having particularly excellent thermal conductivity can be obtained.

The thickness of the reinforcing fiber layer is preferably 10 μm or more and 200 μm or less. When the thickness of the reinforcing fiber layer is 10 μm or less, the strength is weak because the reinforcing fiber layer is too thin, and defects such as tearing when combined with the graphite film are likely to occur. Further, the strength becomes weak when a graphite composite film is used.
On the other hand, if the reinforcing fiber layer is 300 μm or more, the influence of the reinforcing fiber layer on the thermal conductivity of the graphite composite film becomes too great, and the thermal conductivity of the graphite composite film is significantly reduced.

As the reinforcing fiber layer to be used, it is desirable to use a fiber layer in which the orientation of the fibers is aligned in one direction. The reinforcing fiber layer can be made to have a uniform thickness by aligning the orientation of the fibers in one direction. When a plurality of such reinforcing fiber layers are laminated, a graphite composite film that can withstand an impact from any direction can be obtained by orienting these reinforcing fiber layers in different directions. Furthermore, the structure aligned in one direction does not have a portion where fibers overlap each other like a woven structure, and the thickness can be easily adjusted, and many variations of a graphite composite film can be produced.
In the present invention, the plurality of reinforcing fiber layers are oriented in different directions means that when there are a plurality of reinforcing fiber layers aligned in one direction, these are when the graphite composite film is viewed from the plane direction. This means that the fiber direction differs by 5 ° or more.

<Graphite film>
The graphite film of the present invention has anisotropy in thermal conductivity, and has a thermal conductivity of 200 W / (m · K) or more, preferably 500 W / (m · K) in the direction showing good thermal conductivity. More preferably, it is 1000 W / (m · K) or more. As a result, even when composited with the reinforcing fiber layer, the thermal conductivity of the graphite composite film can be set to a good value.
The thickness of the graphite film is desirably 3 μm or more and 500 μm or less. When it is 3 μm or less, it is easy to break when it is combined with the reinforcing fiber layer, and when it is made into a graphite composite film, the graphite film is too thin with respect to the reinforcing fiber layer, so that the thermal conductivity is lowered. When the thickness of the graphite film is 500 μm or more, the influence of the graphite film having a low mechanical strength is conspicuous even when the graphite film is combined with the reinforcing fiber layer. Therefore, the graphite composite film tends to be a material having a low mechanical strength. .

The density of the graphite film of the present invention is usually 1.0 g / cm ³ or more, preferably 1.4 g / cm ³ or more, more preferably 1.8 g / cm ³ or more. The density of the graphite film of the present invention, aluminum (density: 2.70g / cm ³⁾ or copper (Density: 8.96g / cm ³⁾ is smaller than the like, it is possible to reduce the weight of graphite composite film, In the case of the same size and weight, the heat dissipating property can be improved and the heat radiation performance can be improved. Furthermore, the density of the graphite film of the present invention is usually 2.2 g / cm ³ or less. Since the graphite film of the present invention has a higher density than a general graphite film, high thermal conductivity can be realized without including an air layer inside the graphite. Furthermore, the cohesive strength of graphite itself is high, there is no peeling from the surface, and a strong graphite composite film can be obtained.

The MIT of the graphite film is preferably 10,000 times or more. Here, MIT refers to a MIT flex test result, and can be measured using, for example, an MIT fatigue resistance tester model D manufactured by Toyo Seiki Co., Ltd. Since the graphite film of the present invention has flexibility, it is resistant to bending even when a graphite composite film is formed, and the problem of cracks in the graphite film layer is improved.
The water absorption of the graphite film is 2% or less, preferably 1% or less, more preferably 0.5% or less. If the water absorption rate of the graphite film is greater than 2%, the water contained in the graphite film evaporates when the graphite film and the reinforcing fiber layer are bonded together, and floating tends to occur at the interface between the graphite film and the reinforcing fiber layer. If it is used, it becomes easy to cause peeling from the part. In addition, when the graphite film has a water absorption rate of 2% or more, when used in a state of being immersed in high humidity or water, the graphite film expands and deforms due to water absorption, or water is interposed between the graphite film and the reinforcing fiber layer. May be included and peeling may occur at the interface. Furthermore, when graphite composite films are used for electronic equipment and aerospace equipment, low humidity (10 ° C, 15%) and high humidity (30 ° C, 80%), repeated immersion and dryness of water Even in a heat cycle test, it is necessary to maintain quality (strength, interfacial adhesion), and in such a usage method, it is particularly preferable that the water absorption rate is low.

  Moreover, it is preferable that a graphite film has a through-hole. Here, the through hole refers to a hole through which resin penetrates. By providing the through hole, the resin permeates into the opposite surface of the graphite film through the through hole, so that it can be combined more firmly and peeling between layers can be prevented. The through-hole ratio is preferably 3 to 50%, more preferably 3 to 30%, in terms of surface area with respect to the graphite film as seen from the plane direction. If the ratio of the through-holes is 3% or less with respect to the surface of the graphite film, the amount of the resin penetrating the opposite surface of the graphite film is too small, so that there is almost no effect. Further, if the ratio of the through holes is 50% or more with respect to the surface of the graphite film, it is not preferable because the ability of the graphite film to diffuse heat becomes low.

<Production method of graphite film>
The first method for producing a graphite film preferably used for the purpose of the present invention is a graphite film obtained by pressing graphite powder into a sheet. In order for the graphite powder to be formed into a film, the powder needs to be in the form of flakes or flakes. The most common method for producing such graphite powder is a method called an expanded (expanded graphite) method. In this method, graphite is immersed in an acid such as sulfuric acid to produce a graphite intercalation compound, which is then heat treated and foamed to separate the graphite layers. After peeling, the graphite powder is washed to remove the acid to obtain a thin film graphite powder. The graphite powder obtained by such a method is further subjected to rolling roll molding to obtain film-like graphite. The graphite film produced using expanded graphite obtained by such a method is flexible and has a high thermal conductivity in the film surface direction, so that it is preferably used for the purpose of the present invention.

  A second method for producing a graphite film preferably used for the purpose of the present invention is one in which film-like graphite is produced by heat treatment of a polymer film such as a polyimide resin.

  The raw material film of the graphite film used in the second method is polyimide, polyamide, polyoxadiazole, polybenzothiazole, polybenzobisthiazole, polybenzoxazole, polybenzobisoxazole, polyparaphenylene vinylene, polybenzimidazole, It is at least one polymer film selected from polybenzobisimidazole and polythiazole.

  In particular, a polyimide film is preferable as a raw material film for the graphite film of the present invention. Polyimide film is more prone to carbonization and graphitization of film than raw film made from other organic materials, so the thermal diffusivity, thermal conductivity, and electrical conductivity of the film are likely to increase uniformly at low temperatures. In addition, the thermal diffusivity, thermal conductivity, and electrical conductivity itself tend to be high. Further, in addition to the case where the thickness is thin, even when it is thick, the graphite has high thermal conductivity. In addition, the resulting graphite has excellent crystallinity, excellent heat resistance and bendability, and when combined with a reinforcing fiber layer, it is easy to obtain a graphite composite film in which graphite does not easily fall from the surface.

  In order to obtain a graphite film from a polymer, the polymer film as a starting material is first carbonized by preheating treatment under reduced pressure or in an inert gas. This carbonization is usually performed at a temperature of about 1000 ° C., and for example, when the temperature is raised at a rate of 10 ° C./min, it is desirable to hold the temperature for about 30 minutes in the temperature range of 1000 ° C. The graphitization step is performed under reduced pressure or in an inert gas, and argon and helium are suitable as the inert gas. In the method for producing a graphite film of the present invention, the heat treatment temperature is required to be at least 2000 ° C., finally 2400 ° C. or more, more preferably 2600 ° C. or more, more preferably 2800 ° C. or more. By setting the heat treatment temperature to be high, it is possible to obtain graphite having excellent thermal conductivity. The higher the heat treatment temperature is, the higher the quality can be converted to graphite, but from the viewpoint of economy, it is preferable that the conversion to high quality graphite is possible at the lowest possible temperature. In order to obtain an ultra-high temperature of 2500 ° C. or higher, usually, a current is directly applied to the graphite heater, and heating using the Joule heat is performed.

<Resin>
The graphite composite film of the present invention may contain a resin.
The resin used in the present invention is a thermosetting resin and / or a thermoplastic resin.
As the thermosetting resin of the present invention, PU (polyurethane), phenol resin, urea resin, melamine resin, guanamine resin, vinyl ester resin, unsaturated polyester, oligoester acrylate, diallyl phthalate, DKF resin (resorcinol resin) 1 type), xylene resin, epoxy resin, furan resin, PI (polyimide) resin, PEI (polyetherimide) resin, PAI (polyamideimide) resin, and the like. Among them, a resin containing an epoxy resin is preferable because of a wide range of material selection and excellent adhesion between the reinforcing fiber layer and graphite. The epoxy resin is preferably an epoxy resin that is solid at room temperature and melts when heated. By heating and melting, it can be dissolved into the reinforcing fiber layer and the inside of the graphite, and can penetrate into the slight gap in the reinforcing fiber layer and the graphite surface. Furthermore, when cooled, the epoxy resin that has penetrated into the gap between the reinforcing fiber layer and the graphite is solidified, so that a high anchoring effect is expressed between the epoxy resin, the reinforcing fiber layer, and the graphite, and a high adhesive force is expressed, which is preferable. .

  Examples of the thermoplastic resin of the present invention include ionomer, isobutylene maleic anhydride copolymer, AAS (acrylonitrile-acryl-styrene copolymer), AES (acrylonitrile-ethylene-styrene copolymer), AS (acrylonitrile-styrene copolymer). , ABS (acrylonitrile-butadiene-styrene copolymer), ACS (acrylonitrile-chlorinated polyethylene-styrene copolymer), MBS (methyl methacrylate-butadiene-styrene copolymer), ethylene-vinyl chloride (vinyl chloride) copolymer , EVA (ethylene-vinyl acetate copolymer), EVA (ethylene-vinyl acetate copolymer system), EVOH (ethylene vinyl alcohol copolymer), polyvinyl acetate, chlorinated vinyl chloride, chlorinated polyethylene, chlorinated polypropylene , Carboxyvinyl polymer, ketone resin, norbornene resin, vinyl propionate, PE (polyethylene), PP (polypropylene), TPX (polymethylpentene), polybutadiene, PS (polystyrene), styrene maleic anhydride copolymer, methacryl, EMAA (Ethylene-methacrylic acid copolymer), PMMA (polymethyl methacrylate), PVC (polyvinyl chloride), polyvinylidene chloride, PVA (polyvinyl alcohol), polyvinyl ether, polyvinyl butyral, polyvinyl formal, cellulosic, nylon 6, nylon 6 copolymer, nylon 66, nylon 610, nylon 612, nylon 11, nylon 12, copolymer nylon, nylon MXD, nylon 46, methoxymethylated nylon, aramid, ET (polyethylene terephthalate), PBT (polybutylene terephthalate), PC (polycarbonate), POM (polyacetal), polyethylene oxide, PPE (polyphenylene ether), modified PPE (polyphenylene ether), PEEK (polyether ether ketone), PES (poly) Ether sulfone), PSO (polysulfone), polyamine sulfone, PPS (polyphenylene sulfide), PAR (polyarylate), polyparavinylphenol, polyparamethylenestyrene, polyallylamine, aromatic polyester, liquid crystal polymer, PTFE (polytetra) Fluoroethylene), ETFE (tetrafluoroethylene-ethylene copolymer), FEP (tetrafluoroethylene-hexafluoropropylene copolymer) Coalescence), EPE (tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), PCTFE (polychlorotrifluoroethylene copolymer), ECTFE (Ethylene-chlorotrifluoroethylene copolymer), PVDF (polyvinylidene fluoride type), PVF (polyvinyl fluoride) and the like. When used in combination with an epoxy resin, an amide-based resin is preferable because it can exhibit high adhesion. Moreover, by mixing with a thermoplastic resin, it becomes possible to obtain a sheet as a single body, and handling properties during molding are improved. Also, the toughness after molding is greatly improved.

<Composite method of graphite film and reinforcing fiber layer>
The method for producing the graphite composite film of the present invention can be broadly divided into the following two methods.

(1) The first method for producing the graphite composite film of the present invention is a method of laminating a reinforcing fiber layer impregnated with a resin on at least one surface of the graphite film. When the resin impregnated in the reinforcing fiber layer is made of a material containing an epoxy resin having a softening point of 50 ° C. or higher and 100 ° C. or lower, the resin is sufficiently melted and melted into the reinforcing fiber layer and the graphite to strengthen the resin. Penetration into a slight gap on the fiber layer and the graphite surface and cooling are preferable because a high anchoring effect is exhibited between the epoxy resin, the reinforcing fiber layer, and the graphite, and a high adhesive force is exhibited.
Although it does not specifically limit as a reinforcing fiber layer, It is desirable to use what aligned the orientation of the fiber to one direction. The reinforcing fiber layer can be made to have a uniform thickness by aligning the orientation of the fibers in one direction. When a plurality of such reinforcing fiber layers are laminated, a graphite composite film that can withstand an impact from any direction can be obtained by orienting these reinforcing fiber layers in different directions.

(2) The second method for producing the graphite composite film of the present invention is a method of separately preparing a graphite film, a resin film, and a reinforcing fiber layer and laminating them. When the resin layer used in the present invention is made of a material containing an epoxy resin having a softening point of 50 ° C. or higher and 100 ° C. or lower, the resin is sufficiently melted and melted into the reinforcing fiber layer and graphite, and the reinforcing fiber layer and When it penetrates into a slight gap on the graphite surface and is cooled, a high anchoring effect is exhibited between the epoxy resin, the reinforcing fiber layer, and the graphite, and a high adhesive force is exhibited.
The laminating method may be performed using a hot press, a vacuum press, a laminator, an autoclave, or the like.

  Although it does not specifically limit as a reinforcing fiber layer, It is desirable to use what aligned the orientation of the fiber to one direction. The reinforcing fiber layer can be made to have a uniform thickness by aligning the orientation of the fibers in one direction. When a plurality of such reinforcing fiber layers are laminated, a graphite composite film that can withstand an impact from any direction can be obtained by orienting these reinforcing fiber layers in different directions.

The ratio T _F / T _G of the thickness T _F of the reinforcing fiber layer and the thickness T _G of the graphite film is preferably 0.1 or more and 20 or less. If T _F / _TG is 0.1 or less, the strength of the graphite composite film is significantly reduced, which is not preferable. Further, if T _F / _TG is 20 or more, the thermal conductivity is remarkably lowered, which is not preferable.

  The graphite composite film of the present invention has anisotropy in thermal conductivity and a thermal conductivity in the plane direction of 10 W / (m · K) or more, preferably 50 W / (m · K) or more. As a result, when the graphite composite film prepared in this way is used as an electronic material, housing, aircraft member, etc., heat is quickly released to the entire graphite composite film before it is transferred to the outside of the graphite composite film. It is preferable because

  The graphite composite film of the present invention has a tensile strength of 300 MPa or more, preferably 500 MPa or more. When the tensile strength is 300 MPa or more, the handleability is remarkably improved, and a material having high strength can be provided.

Further, the present invention may include the following inventions.
(1) A first aspect of the present invention is a graphite composite film characterized in that a reinforcing fiber layer is formed on at least one surface of the graphite film.

(2) A second aspect of the present invention is the graphite composite film,
a) The thickness of the graphite film is 3 μm or more and 500 μm or less,
b) the thickness of the reinforcing fiber layer is at 10μm or 300μm or less c) the ratio T _F / T _G of the thickness T _G of the thickness T _F of the reinforcing fiber layer and the graphite film is 0.1 to 20 The graphite composite film according to claim 1.

  (3) A third aspect of the present invention is that the graphite film is formed of polyimide, polyamide, polyoxadiazole, polybenzothiazole, polybenzobisthiazole, polybenzoxazole, polybenzobisoxazole, polyparaphenylene vinylene, polybenzimidazole. The graphite composite according to (1) or (2), wherein the graphite composite is obtained by heat treatment of at least one polymer selected from the group consisting of polybenzobisimidazole and polythiazole It is a film.

  (4) In the fourth aspect of the present invention, any one of (1) to (3), wherein the graphite film has an MIT of 10,000 times or more, and the graphite film has a water absorption of 2% or less. The graphite composite film described in 1.

  (5) The graphite according to any one of (1) to (4), wherein the reinforcing fiber layer is obtained by impregnating a fiber with a thermosetting resin and / or a thermoplastic resin. It is a composite film.

  (6) A sixth aspect of the present invention is a reinforcing fiber layer in which the reinforcing fiber layer is composed of at least one kind of fiber selected from the group consisting of carbon fiber, aramid fiber, glass fiber, synthetic fiber, natural fiber, and nylon. It is a graphite composite film according to any one of (1) to (5).

  (7) A seventh aspect of the present invention is the graphite composite film according to any one of (1) to (6), wherein the graphite film has a through hole.

  (8) According to an eighth aspect of the present invention, in the graphite composite film according to any one of (1) to (7), the reinforcing fiber layer has a fiber orientation aligned in one direction. It is.

  (9) In the ninth aspect of the present invention, in the graphite composite film having two or more reinforcing fiber layers in which the fibers are aligned in one direction, at least one reinforcing fiber layer is oriented in different directions. The graphite composite film described in (8), which is characterized.

  (10) A tenth aspect of the present invention is the graphite composite film according to any one of (1) to (9), wherein the thermal conductivity in the surface direction of the graphite composite film is 10 W / (m · K) or more.

  (11) The eleventh aspect of the present invention is the graphite composite film according to any one of (1) to (10), wherein the graphite composite film has a tensile strength of 300 MPa or more.

Embodiments and effects of the present invention will be described below with reference to examples, but the present invention is not limited thereto.

<Graphite film>
[Graphite film A]
In a DMF (dimethylformamide) solution in which 1 equivalent of 4,4′-oxydianiline was dissolved, 1 equivalent of pyromellitic dianhydride was dissolved to obtain a polyamic acid solution (18.5 wt%). While this solution was cooled, an imidation catalyst containing 1 equivalent of acetic anhydride, 1 equivalent of isoquinoline, and DMF was added to the carboxylic acid group contained in the polyamic acid to degas. Next, this mixed solution was applied onto an aluminum foil so as to have a predetermined thickness after drying. The mixed solution layer on the aluminum foil was dried using a hot air oven and a far infrared heater. As described above, a polyimide film having a thickness of 50 μm (elasticity 3.1 GPa, water absorption 2.5%, birefringence 0.10, linear expansion coefficient 3.0 × 10 ⁻⁵ / ° C.) was produced.

The polyimide film thus prepared was sandwiched between graphite plates and heated to 1000 ° C. using an electric furnace to perform carbonization treatment (carbonization treatment). The carbonized film A obtained by the carbonization treatment was sandwiched between graphite plates, and was graphitized by raising the temperature to 2900 ° C. or higher using a graphitization furnace. The heat-treated graphite is compressed in the thickness direction by a single plate press to obtain a graphite film (thickness 25 μm, density 1.86 g / cm ³ , thermal diffusivity 9.1 cm ² / s, thermal conductivity 1200 W / (m · K ), MIT> 10000 times, water absorption 0%).

[Graphite film B]
A graphite film B (and a thickness of 40 μm, a density of 1.86 g / cm ³ , a thermal diffusivity of 9.5 cm ² / s, and a thermal conductivity of 1200 W except that a polyimide film having a thickness of 75 μm was used. / (M · K), MIT> 10000 times, water absorption 0%).

[Graphite film C]
In the presence of an oxidizing agent (hydrogen peroxide, perchloric acid, etc.), sulfuric acid, nitric acid, etc. are inserted between the layers of natural scaly graphite, and the formed intercalation compound is rapidly heated at 5 high temperatures of about 900 to 1200 ° C. The gas was decomposed and gas was expanded to expand the graphite layer by the gas pressure at this time. The expanded graphite obtained as described above is compression-preformed, and then rolled with a roll to obtain a graphite film F (thickness 100 μm, density 1.67 g / cm ³ , thermal diffusivity 3.0 cm ² / s, thermal conductivity 250 W / (m · K), MIT <10 times, water absorption 50%).

[Graphite film D]
In the presence of an oxidizing agent (hydrogen peroxide, perchloric acid, etc.), sulfuric acid, nitric acid, etc. are inserted between the layers of natural scaly graphite, and the formed intercalation compound is rapidly heated at 5 high temperatures of about 900 to 1200 ° C. The gas was decomposed and gas was expanded to expand the graphite layer by the gas pressure at this time. The expanded graphite obtained as described above is compression-preformed and then rolled with a roll to obtain a graphite film F (thickness 250 μm, density 1.67 g / cm ³ , thermal diffusivity 3.0 cm ² / s, thermal conductivity 250 W / (m · K), MIT <10 times, water absorption 50%).

[Graphite film E]
Through-holes having a diameter of 3 mm were equally provided in the graphite film A so as to be 20% of the surface area, thereby obtaining a graphite film E.
<Measurement of properties of graphite film>
As a method for measuring the thickness of the graphite film, a film of 50 mm × 50 mm was measured at any 10 points in a constant temperature room at 25 ° C. using a thickness gauge (HEIDENHAIN-CERTO, manufactured by HEIDENHAIN Co., Ltd.). The average value was taken as the measured value.

The density of the graphite film was calculated by dividing the weight (g) of the graphite film by the volume (cm ³ ) calculated by the product of the vertical, horizontal and thickness of the graphite film. In addition, the average value measured by arbitrary 10 points | pieces was used for the thickness of a graphite film. The higher the density, the more remarkable the graphitization.

The thermal diffusivity of the graphite film was measured by cutting the graphite film into a 4 × 40 mm sample shape using a thermal diffusivity measuring apparatus (“LaserPit” available from ULVAC-RIKO Co., Ltd.) by an optical alternating current method, The measurement was performed at 10 Hz under the atmosphere of The progress of graphitization was determined by measuring the thermal diffusivity in the film surface direction. Higher thermal diffusivity means more remarkable graphitization. The thermal conductivity of the graphite film was calculated from the thermal diffusivity, density, and specific heat as shown in the following equation.
λ = αdC
λ: thermal conductivity (W / (m · K))
α: Thermal diffusivity (m ² / s)
d: Density (kg / m ³ )
C: Specific heat (J / kg · K)
<MIT Film Flex Test>
A graphite film is cut to 1.5 × 10 cm, and a test load of 100 gf (0.98 N), a speed of 90 times / min, and a curvature of a bending clamp using a model D made by Toyo Seiki Co., Ltd. Measurement was performed with a radius of R1 mm and a bending angle of 135 ° to the right.

<Water absorption of graphite film>
The water absorption rate of the film was measured as follows. In order to completely dry the film, the film was dried at 100 ° C. for 30 minutes to prepare a sample having a 25 μm thickness and a 10 cm square. This weight is measured as W1. A 25 μm-thick 10 cm square sample was immersed in distilled water at 23 ° C. for 24 hours, and the surface water was wiped away and the weight was immediately measured. Let this weight be W2. The water absorption was determined from the following formula.
Water absorption rate (%) = (W2−W1) ÷ W1 × 100
<Reinforcing fiber layer>
The reinforcing fiber layer was used by impregnating the reinforcing fiber with epoxy resin in advance.

[Reinforcing fiber layer A]
Fiber: Carbon fiber, Fiber form: Unidirectional alignment, Resin: Epoxy resin,
Fiber content: 147 g / m ² , thickness: 0.14 mm, resin content: 34.0%
[Reinforcing fiber layer B]
Fiber: Carbon fiber, Fiber form: Unidirectional alignment, Resin: Epoxy resin,
Fiber content: 20 g / m ² , thickness: 0.025 mm, resin content: 40.0%
[Reinforcing fiber layer C]
Fiber: Carbon fiber, Fiber form: Textile, Resin: Epoxy resin,
Fiber content: 197 g / m ² , thickness: 0.22 mm, resin content: 40.0%
[Reinforcing fiber layer D]
Fiber: aramid fiber, fiber form: woven fabric, resin: epoxy resin fiber content: 140 g / m ² , thickness: 0.14 mm, resin content: 40.0%
[Reinforcing fiber layer E]
Fiber: Glass fiber, Fiber form: Textile, Resin: Epoxy resin Fiber content: 140 g / m ² , thickness: 0.14 mm, resin content: 40.0%
(Reference Example 1)
The graphite film A was bonded to the reinforcing fiber layer A, held at 80 ° C. and normal pressure for 30 minutes by hot pressing, and then held at 130 ° C. and pressure of 5 kg / cm ² for 90 minutes to cure the epoxy resin. Thereafter, cooling was performed by a cooling press to prepare a graphite composite film having a structure of graphite film A / reinforced fiber layer A. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Reference Example 2)
The graphite film A was bonded to the reinforcing fiber layer B, held at 80 ° C. and normal pressure for 30 minutes by hot pressing, and then held at 130 ° C. and pressure of 5 kg / cm ² for 90 minutes to cure the epoxy resin. Thereafter, cooling was performed by a cooling press to prepare a graphite composite film having a structure of graphite film A / reinforced fiber layer B. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Reference Example 3)
The graphite film B was bonded to the reinforcing fiber layer A, held at 80 ° C. and normal pressure for 30 minutes by hot pressing, and then held at 130 ° C. and pressure of 5 kg / cm ² for 90 minutes to cure the epoxy resin. Thereafter, cooling was performed by a cooling press to prepare a graphite composite film having a structure of graphite film B / reinforced fiber layer A. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Reference Example 4)
The graphite film B was bonded to the reinforcing fiber layer B, held at 80 ° C. and normal pressure for 30 minutes by hot pressing, and then held at 130 ° C. and pressure of 5 kg / cm ² for 90 minutes to cure the epoxy resin. Thereafter, cooling was performed by a cooling press to prepare a graphite composite film having a structure of graphite film B / reinforced fiber layer B. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Reference Example 5)
The graphite film C was bonded to the reinforcing fiber layer A, held at 80 ° C. and normal pressure for 30 minutes by hot pressing, and then held at 130 ° C. and pressure of 5 kg / cm ² for 90 minutes to cure the epoxy resin. Thereafter, cooling was performed by a cooling press to prepare a graphite composite film having a structure of graphite film C / reinforced fiber layer A. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Reference Example 6)
The graphite film C was bonded to the reinforcing fiber layer B, held at 80 ° C. and normal pressure for 30 minutes by hot pressing, and then held at 130 ° C. and pressure of 5 kg / cm ² for 90 minutes to cure the epoxy resin. Thereafter, cooling was performed by a cooling press to prepare a graphite composite film having a structure of graphite film C / reinforced fiber layer B. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Reference Example 7)
The graphite film D was bonded to the reinforcing fiber layer A, held at 80 ° C. and normal pressure for 30 minutes by hot pressing, and then held at 130 ° C. and pressure of 5 kg / cm ² for 90 minutes to cure the epoxy resin. Thereafter, cooling was performed by a cooling press to prepare a graphite composite film having a structure of graphite film D / reinforced fiber layer A. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Reference Example 8)
The graphite film D was bonded to the reinforcing fiber layer B, held at 80 ° C. and normal pressure for 30 minutes by hot pressing, and then held at 130 ° C. and pressure of 5 kg / cm ² for 90 minutes to cure the epoxy resin. Thereafter, cooling was performed by a cooling press to prepare a graphite composite film having a structure of graphite film D / reinforced fiber layer B. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Reference Example 9)
The films were bonded together in a configuration of reinforcing fiber layer A (0 °) / graphite film A / reinforcing fiber layer A (90 °), held at 80 ° C. for 30 minutes at normal pressure by hot pressing, then 130 ° C., 5 kg / cm. ^The epoxy resin was cured by holding at a pressure of ² for 90 minutes. Then, it cooled by the cooling press and produced the graphite composite film. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Reference Example 10)
The films were bonded together in the configuration of reinforcing fiber layer A (0 °) / graphite film B / reinforcing fiber layer A (90 °), held at 80 ° C. for 30 minutes at normal pressure by hot pressing, then 130 ° C., 5 kg / cm. ^The epoxy resin was cured by holding at a pressure of ² for 90 minutes. Then, it cooled by the cooling press and produced the graphite composite film. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Reference Example 11)
The films were bonded together in the configuration of reinforcing fiber layer A (0 °) / graphite film D / reinforcing fiber layer A (90 °), held at 80 ° C. for 30 minutes at normal pressure by hot pressing, then 130 ° C., 5 kg / cm. ^The epoxy resin was cured by holding at a pressure of ² for 90 minutes. Then, it cooled by the cooling press and produced the graphite composite film. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Example 12)
The films were bonded together in the configuration of reinforcing fiber layer A (0 °) / graphite film E (with through holes) / reinforcing fiber layer A (90 °), kept at 80 ° C. for 30 minutes at normal pressure by hot pressing, and then 130 The epoxy resin was cured by holding at 90 ° C. and a pressure of 5 kg / cm ² for 90 minutes. Then, it cooled by the cooling press and produced the graphite composite film. The constitution is summarized in Table 1, and the results are summarized in Table 2. Here, the ratio of the through holes of the graphite film was 20%.

(Reference Example 13)
The films were bonded together in the configuration of reinforcing fiber layer D (0 °) / graphite film A / reinforcing fiber layer D (90 °), kept at 80 ° C. for 30 minutes at normal pressure by hot pressing, then 130 ° C., 5 kg / cm. ^The epoxy resin was cured by holding at a pressure of ² for 90 minutes. Then, it cooled by the cooling press and produced the graphite composite film. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Reference Example 14)
The films were bonded together in the configuration of reinforcing fiber layer E (0 °) / graphite film A / reinforcing fiber layer E (90 °), kept at 80 ° C. for 30 minutes at normal pressure by hot pressing, then 130 ° C., 5 kg / cm. ^The epoxy resin was cured by holding at a pressure of ² for 90 minutes. Then, it cooled by the cooling press and produced the graphite composite film. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Reference Example 15)
A film is laminated with a configuration of reinforcing fiber layer A (−45 °) / reinforcing fiber layer A (0 °) / graphite film A / reinforcing fiber layer A (45 °) / reinforcing fiber layer A (90 °), and hot press Was held at 80 ° C. for 30 minutes at normal pressure and then held at 130 ° C. for 90 minutes at a pressure of 5 kg / cm ² to cure the epoxy resin. Then, it cooled by the cooling press and produced the graphite composite film. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Reference Example 16)
The films were bonded together in the form of graphite film A / reinforcing fiber layer A (0 °) / graphite film A, held at 80 ° C. and normal pressure for 30 minutes by hot pressing, and then at 130 ° C. and 5 kg / cm ² pressure. Hold for 90 minutes to cure the epoxy resin. Then, it cooled by the cooling press and produced the graphite composite film. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Reference Example 17)
The films were bonded together in the form of graphite film B / reinforcing fiber layer A (0 °) / graphite film B, held at 80 ° C. and normal pressure for 30 minutes by hot pressing, and then at 130 ° C. and 5 kg / cm ² pressure. Hold for 90 minutes to cure the epoxy resin. Then, it cooled by the cooling press and produced the graphite composite film. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Reference Example 18)
The films were bonded together in the form of graphite film D / reinforcing fiber layer A (0 °) / graphite film D, held at 80 ° C. and normal pressure for 30 minutes by hot pressing, and then at 130 ° C. and 5 kg / cm ² pressure. Hold for 90 minutes to cure the epoxy resin. Then, it cooled by the cooling press and produced the graphite composite film. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Reference Example 19)
The films were bonded together in the form of graphite film D / reinforcing fiber layer B (0 °) / graphite film D, held at 80 ° C. and normal pressure for 30 minutes by hot pressing, and then at 130 ° C. and 5 kg / cm ² pressure. Hold for 90 minutes to cure the epoxy resin. Then, it cooled by the cooling press and produced the graphite composite film. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Example 20)
The films were bonded together in the form of graphite film E (with through-holes) / reinforced fiber layer A (0 °) / graphite film E (with through-holes), held at 80 ° C. for 30 minutes at normal pressure by hot pressing, and then 130 The epoxy resin was cured by holding at 90 ° C. and a pressure of 5 kg / cm ² for 90 minutes. Then, it cooled by the cooling press and produced the graphite composite film. The constitution is summarized in Table 1, and the results are summarized in Table 2. Here, the ratio of the through holes of the graphite film was 20%.

(Reference Example 21)
The graphite film A was bonded to the reinforcing fiber layer C, held at 80 ° C. and normal pressure for 30 minutes by hot pressing, and then held at 130 ° C. and pressure of 5 kg / cm ² for 90 minutes to cure the epoxy resin. Thereafter, cooling was performed by a cooling press to prepare a graphite composite film having a structure of graphite film A / reinforced fiber layer C. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Reference Example 22)
The graphite film B was bonded to the reinforcing fiber layer C, held at 80 ° C. and normal pressure for 30 minutes by hot pressing, and then held at 130 ° C. and pressure of 5 kg / cm ² for 90 minutes to cure the epoxy resin. Thereafter, cooling was performed by a cooling press to prepare a graphite composite film having a structure of graphite film B / reinforced fiber layer C. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Reference Example 23)
The graphite film D was bonded to the reinforcing fiber layer C, held at 80 ° C. and normal pressure for 30 minutes by hot pressing, and then held at 130 ° C. and pressure of 5 kg / cm ² for 90 minutes to cure the epoxy resin. Thereafter, cooling was performed by a cooling press to prepare a graphite composite film having a structure of graphite film D / reinforced fiber layer C. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Comparative Example 1)
Using graphite film A, the constitution is summarized in Table 1, and the results are summarized in Table 2.

(Comparative Example 2)
Using graphite film D, the constitution is summarized in Table 1, and the results are summarized in Table 2.

(Comparative Example 3)
The films were bonded together with the configuration of reinforcing fiber layer A (0 °) / reinforced fiber layer A (90 °), kept at 80 ° C. and normal pressure for 30 minutes by hot pressing, and then adjusted to 130 ° C. and 5 kg / cm ² pressure. Held for 90 minutes to cure the epoxy resin. Thereafter, the sample was cooled by cooling with a cooling press. The constitution is summarized in Table 1, and the results are summarized in Table 2.

(Comparative Example 4)
A graphite prepreg prepared by applying and drying an epoxy resin on both sides of the graphite film A was held at 80 ° C. and normal pressure for 30 minutes by hot pressing, and then held at 130 ° C. and a pressure of 5 kg / cm ² for 90 minutes. The epoxy resin was cured. Thereafter, the sample was cooled by cooling with a cooling press. The constitution is summarized in Table 1, and the results are summarized in Table 2.

<Thermal conductivity of graphite composite film>
The thermal diffusivity and the thermal conductivity were measured by cutting the test piece into a diameter of 25.4 mm and measuring the thermal diffusivity by a laser flash method at room temperature. Moreover, the heat capacity of the graphite film was derived from a comparison with a reference standard substance Mo having a known heat capacity. The measured thermal conductivity of the graphite composite film was calculated from the thermal diffusivity, density, and specific heat as shown in the following equation.
λ = αdC
λ: thermal conductivity (W / (m · K))
α: Thermal diffusivity (m ² / s)
d: Density (kg / m ³ )
C: Specific heat (J / kg · K)
When the thermal conductivity is 200 W / (m · K) or more “◎”, when 50 W / (m · K) to 199 W / (m · K) “◯”, when 10 to 49 W / (m · K) “△” and “x” when less than 10 W / (m · K).

<Tensile strength measurement>
Measurement was performed in accordance with JIS K 7078 using a strograph VES1D manufactured by Toyo Seiki Seisakusho. The measurement was carried out three times at a room temperature of 100 mm, a tensile speed of 50 mm / min, and room temperature, and the average value was used. When the average value is 500 MPa or more, “◯” is indicated, and when the average value is less than 500 MPa, “X” is indicated. When there was anisotropy in the tensile strength, the measurement was performed using a sample in the direction in which the value was the largest, and evaluated.

<Measurement of bending strength>
A three-point bending test was performed in accordance with JIS K7074. The measurement was performed 5 times, and “◯” was given when the average value of bending strength was 500 MPa or more, “Δ” when the average value was 100 MPa to 499 MPa, and “x” when the average value was less than 100 MPa.

<Flexibility evaluation>
Cut the sample to 150mm width, grab the opposite sides, bend it so that the opposite sides come into contact, and if the sample breaks or breaks, scratches, etc. before the opposite sides come into contact, “×”, When it was bent until it contacted, it was set as “◯”.

The thermal conductivity of the reference example and Examples 1 to 23 all showed a good value of 10 W / (m · K) or more. It is considered that the smaller the value of T _F / T _G, the greater the effect of the graphite film having the characteristics of high thermal conductivity, and the higher the thermal conductivity, especially when the T _F / T _G is 5 or less. The thermal conductivity also showed a good value, showing a value of 200 W / (m · K) or more.

However, in the configuration of Reference Example 15, the thermal conductivity was a little lower than 50 W / (m · K). This is considered to be because the ratio of the carbon fiber to the graphite film is increased ( _TF / T _G = 22.4). When the thickness of the graphite film becomes extremely small with respect to the thickness of the carbon fiber, heat is generated. It means that the conductivity is getting lower. In addition, the graphite film obtained by heat-treating the polymer has a more advanced layered graphite structure in the plane of the film than the graphite film produced by compressing expanded graphite. Therefore, the effect of improving the thermal conductivity when the graphite composite film was used was also high. On the other hand, with respect to the strength, in the structure in which the graphite film was provided alone or on both sides of the graphite film as in Comparative Examples 1, 2, and 4, both the bending strength and the tensile strength were weak, and tearing was likely to occur. On the other hand, in the case where the reinforcing fiber layer was provided, the strength was improved in all cases, and when the total thickness of the reinforcing fiber layer was increased, the strength tended to increase. However, when the thickness (T _G ) of the graphite film becomes extremely thick with respect to the thickness (T _F ) of the reinforcing fiber layer as in Reference Example 19 (T _F / T _G = 0.05), the graphite film made of reinforcing fibers. Therefore, when the bending strength test is performed, the graphite layer portion is likely to be destroyed. On the other hand, flexibility is attributed to the thickness of the reinforcing fiber layer, and the configuration as in Comparative Example 3 in which two 140 μm thick reinforcing fiber layers are bonded together, and the total thickness of the reinforcing fiber layer is the largest. In the configuration as in Reference Example 15, the strength was high, but the flexibility was so hard that it was difficult to bend and easily cracked. However, when the reinforcing fiber layer has a thinner structure as in Reference Example 2, the graphite film can be easily folded without losing its flexibility. In addition, when the flexibility was evaluated, the type of graphite film used was a graphite film made by compressing expanded graphite, and cracks were likely to occur in the graphite part as the deflection increased. However, the configuration using a polymer obtained by heat treatment showed good flexibility even when bent, and improved flexibility compared to the former. From this, it can be said that the flexibility of the graphite composite film combined with the reinforcing fiber is also influenced by the flexibility of the graphite film itself. Therefore, it is considered that the better the MIT of the graphite film, the more flexible the graphite composite film. Moreover, when the graphite film provided with the through hole as in Examples 12 and 20 was used, the thermal conductivity was somewhat lowered, but the adhesiveness between the graphite film and the reinforcing fiber layer was improved by filling the through hole with the resin. As a result, peeling between layers is less likely to occur.

Claims (17)

A reinforcing fiber layer is formed on at least one side of the graphite film having a through hole,
The reinforcing fiber layer is obtained by impregnating a fiber with a thermosetting resin and / or a thermoplastic resin,
The graphite composite film, wherein the thermosetting resin and / or thermoplastic resin fills the through hole. A reinforcing fiber layer is formed on at least one side of the graphite film having a through hole,
The reinforcing fiber layer is obtained by impregnating a fiber with a thermosetting resin and / or a thermoplastic resin,
The graphite composite film, wherein the thermosetting resin and / or thermoplastic resin penetrates into the opposite surface of the graphite film through the through hole. A reinforcing fiber layer is formed on at least one side of the graphite film having a through hole,
The reinforcing fiber layer is obtained by impregnating a fiber with a thermosetting resin and / or a thermoplastic resin,
A graphite composite film obtained by bonding a reinforcing fiber layer to the graphite film and melting and laminating a resin.   4. The graphite composite film according to claim 3, wherein the lamination is performed using a hot press, a vacuum press, a laminator, or an autoclave.   The graphite composite film according to any one of claims 1 to 4, wherein the reinforcing fiber layer is a fiber impregnated with an epoxy resin.   The graphite composite film according to any one of claims 1 to 5, wherein a ratio of the through holes is 3 to 50% in terms of a surface area with respect to the graphite film when viewed from a plane direction. In the graphite composite film,
a) The thickness of the graphite film is 3 μm or more and 500 μm or less,
b) the thickness of the reinforcing fiber layer is at 10μm or 300μm or less c) the ratio T _F / T _G of the thickness T _G of the thickness T _F of the reinforcing fiber layer and the graphite film is 0.1 to 20 The graphite composite film according to any one of claims 1 to 6.   The graphite film is made of polyimide, polyamide, polyoxadiazole, polybenzothiazole, polybenzobisthiazole, polybenzoxazole, polybenzobisoxazole, polyparaphenylene vinylene, polybenzimidazole, polybenzobisimidazole, and polythiazole. The graphite composite film according to any one of claims 1 to 7, which is obtained by heat treatment of at least one polymer selected from the group consisting of:   The graphite composite film according to any one of claims 1 to 8, wherein the graphite film has an MIT of 10,000 times or more, and further has a water absorption of 2% or less.   The reinforcing fiber layer is a reinforcing fiber layer made of at least one kind of fiber selected from the group consisting of carbon fiber, aramid fiber, glass fiber, synthetic fiber, natural fiber, and nylon. The graphite composite film described.   The graphite composite film according to any one of claims 1 to 10, wherein the reinforcing fiber layer is a reinforcing fiber layer in which the orientation of fibers is aligned in one direction.   The graphite composite film having two or more reinforcing fiber layers in which fiber orientations are aligned in one direction, wherein at least one reinforcing fiber layer is oriented in different directions. Composite film.   The graphite composite film according to any one of claims 1 to 12, wherein a thermal conductivity in a plane direction of the graphite composite film is 10 W / (m · K) or more.   The graphite composite film according to any one of claims 1 to 13, wherein the graphite composite film has a tensile strength of 300 MPa or more.   A graphite composite film comprising a step of bonding a reinforcing fiber layer impregnated with a thermosetting resin and / or a thermoplastic resin to a fiber and melting and laminating the resin on at least one surface of the graphite film having a through hole Manufacturing method.   The method for producing a graphite composite film according to claim 15, wherein the lamination is performed using a hot press, a vacuum press, a laminator, or an autoclave. The said graphite composite film is what is described in any one of Claims 1-14, The manufacturing method of the graphite composite film of Claim 15 or 16 characterized by the above-mentioned.