JP3061247B2 - Graphite film, graphitic molded product, precursor film thereof, and production method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graphite film or sheet having excellent film strength and flexibility, and a spiral material, a laminate, a polyhedron, a sphere, etc. formed using the graphite film. The present invention relates to a graphitic molded article containing a three-dimensional structure having a complicated shape, a precursor film for producing a graphitic film, and methods for producing the same.

[0002] The graphitic molded article of the present invention has been processed in a free end state at a high temperature of 2500 ° C or higher,
It is composed of a graphite film with excellent strength and elongation. It is used for electrode materials, heating elements, structural materials, heat-resistant materials, heat-resistant seal materials, X-ray parts, etc. It can also be applied to molded articles and the like.

[0003]

2. Description of the Related Art Graphite materials have been widely used as industrial materials such as electrode materials, heating elements, and structural materials such as heat insulating materials because of their excellent heat resistance, chemical resistance, and electrical conductivity. A graphite material in the form of a film or a sheet for use in the above applications is already known (for example, see JP-A-5-4).
See JP-A-3213, JP-A-4-149013, and JP-A-3-75211. ).

[0004] The conventional method for producing a graphitic film is as follows.
A polymer film such as an aromatic polyimide film, which is a polymer, is used as a precursor, which is carbonized (fired) at a high temperature of 1000 ° C. or more to form a carbonized film, subjected to a rolling treatment, and further broken into molecular chains. A method of repeating a recombination to generate various gases as decomposition products and finally forming a graphitic film in which six-membered ring-like planar molecules are formed.

[0005]

When a three-dimensional three-dimensional structure is manufactured using the graphite film obtained by the conventional method for manufacturing a graphite film, the tensile strength and the tensile strength of the graphite film are reduced. Since the elongation is weak, the graphite film is broken by bending or the like, and there is a problem that processing characteristics are poor. In addition, it has been difficult to manufacture a three-dimensional three-dimensional structure such as a polygonal body or a spherical body having a complicated shape.

The conventional graphite film has a tensile strength of 10.0 kgf / mm ² or more and a tensile elongation of 1.0 kgf / mm ² .
There was no report of a tough and flexible graphite film of 5 % or more. In addition, there has been no report on a three-dimensionally complicated graphitic molded body having excellent strength and flexibility made of such a graphitic film.

In order to solve such a problem, the present invention is to form a three-dimensionally complicated graphitic structure such as a polyhedron or a sphere having a high tensile strength and tensile elongation. To provide a graphitic film which can be formed, to provide a graphitic molded article having a high strength and flexibility which can have a complicated shape in three dimensions, and to manufacture such a graphitic film and a graphitic molded article. It is an object of the present invention to provide a precursor film for producing the film, and to provide a method for producing the precursor film.

[0008]

In order to solve the above-mentioned problems, the graphite film of the present invention has a tensile strength of 1 %.
0.0kgf / mm ² or more, tensile elongation of 1.5% or more, and carbon content of 99% by weight or more.

The graphitic molded article of the present invention has a tensile strength of 1
It is characterized by being formed from a graphitic film having 0.0 kgf / mm ² or more, a tensile elongation of 1.5 % or more, and a carbon content of 99% by weight or more.

[0010] The method for producing a graphitic film of the present invention comprises:
(1) The glass transition temperature is 350 ° C or higher, and the tensile strength is 1
0 kgf / mm ² or more and tensile modulus of 200 kgf
/ Mm ² or more, and the difference in the tensile strength between the warp direction and the transverse direction of the film and the difference in the elastic modulus in each of these directions are within 10%, respectively. (2) Then, the obtained carbonized film is heat-treated at a temperature of 2500 ° C. or more in an inert gas or vacuum.

Another method for producing a graphitic film according to the present invention comprises the steps of (1) having a glass transition temperature of 350 ° C. or more, a tensile strength of 10 kgf / mm ² or more, and a tensile modulus of 200 k
gf / mm ² or more polyimide film having a difference in tensile strength between the longitudinal direction and the transverse direction of the film and a difference in elastic modulus in each direction of 10% or less in a free end state. (2) Then, the obtained carbonized film is heat-treated at a temperature of 2500 ° C. or more in an inert gas or vacuum, and (3) Then, the obtained graphitic film is It is characterized by performing a rolling process.

[0012] A method for producing a graphitic molded article of the present invention is characterized in that molding is performed using the above-mentioned graphitic film.

[0013] Another method for producing a graphitic molded article of the present invention comprises:
(1) The glass transition temperature is 350 ° C or higher, and the tensile strength is 1
0 kgf / mm ² or more and tensile modulus of 200 kgf
/ Mm ² or more polyimide film having a difference in tensile strength between the warp direction and the transverse direction and a difference in elastic modulus in each direction of 10% or less of the polyimide film at a free end. (2)
Next, the compact is carbonized in a free end state in an inert gas or vacuum, and (3) heat-treated at a temperature of 2500 ° C. or more.

The precursor film for producing a graphitic film of the present invention has a glass transition temperature of 350 ° C. or more, a tensile strength of 10 kgf / mm ² or more, and a tensile modulus of 200 kg.
a polyimide film of f / mm ² or more, and a difference in tensile strength between the longitudinal direction and the transverse direction of the film and a difference in elastic modulus in each of the directions within 10%. I do.

The present invention will be described in more detail. In the present invention, "free end", "free end state" refers to a state in which any two points in the film are not fixed, that is, a state in which the film can freely shrink,
Further, "processing at the free end" means processing in such a state, that is, processing in a state where it can be contracted freely. To make the film free end, for example,
In the case of a long film, the core can be removed after winding the film around the core to obtain a free end state. In addition, the film can be folded, and in the case of a short film, it may be used as it is.

In the present invention, polyimide which can be used as a precursor film for producing a graphitic film includes:
Polyimide reacted with a known method using tetracarboxylic dianhydride and aromatic diamine, or can be obtained by reacting with a known method using tetracarboxylic dianhydride, aromatic diamine and polyvalent amine. It is possible.

Representative monomer components of polyamic acid, which is a precursor of a polyimide film, include pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, and benzophenonetetracarboxylic dianhydride as tetracarboxylic dianhydrides. It is listed as. Examples of the aromatic diamine include paraphenylenediamine, metaphenylenediamine, benzidine, o-toluidine, 3,3'-dichloro-4,4'-diaminobiphenyl, 4,4'-diaminodiphenylmethane, and 4,4'-diaminodiphenyl ether. And the like are typical examples.

As another monomer component, a polyvalent amine having three or more amine groups and / or ammonium bases in one molecular structure may be used. Examples of polyamines include 3,3 ', 4,4'-tetraaminobiphenyl, 3,3', 4-triaminobiphenyl, 1,2,4
-Triaminobenzene, 3,3 ', 4,4'-tetraaminobiphenyl tetrahydrochloride, and the like.

A polyimide film prepared by reacting these tetracarboxylic dianhydrides with an aromatic diamine to prepare a polyamic acid as a precursor, or a tetracarboxylic dianhydride and an aromatic diamine and a polyamine are prepared. In the polyimide film produced by the reaction, it is possible to use a single or a mixture of two or more of the respective monomer components, respectively, the resulting polymer other than the copolymer, the polyimide consisting of a specific component, A polyimide blend film in which at least one of the constituent components of the polyimide is mixed with a different polyimide is also included.

Examples of the solvent used for solution polymerization of polyamic acid include amide solvents such as dimethylformamide and N-methyl-2-pyrrolidone.

[0021] The polyimide film serving as a precursor of the graphite film may contain other high molecular weight components at the time of film formation. As the high molecular weight component to be composited with the polyimide film, a known component can be used. At least one kind of high molecular weight component selected from the above can be used as the composite component. It is preferable that these high molecular weight components have a property of being thermally decomposed by a high temperature treatment for carbonization and tending to be graphitized.

The amount of the high molecular weight component depends on the type of the high molecular weight component to be compounded, but it is preferable to add the high molecular weight component within a range that does not impair the strength and elongation of the finally obtained graphite film. 20 mol% to 80 mol% of the whole
Is preferable. (One polymer repeating unit is 1
Mole). These high molecular weight components include modified products of the above polymers, copolymers, precursors, and oligomers, and in the case of precursors and oligomers, may be used by further increasing the molecular weight by a polymerization reaction or the like after compounding. I don't care.

The process for producing a precursor film for producing a graphitic film according to the present invention comprises the above-mentioned monomer components, for example, generally tetracarboxylic dianhydride and aromatic diamine, or tetracarboxylic dianhydride or aromatic diamine. And polyamines are reacted in a solvent by a polyaddition reaction by a low-temperature solution polymerization method, and the resulting polymer solution [polyamide acid (a precursor of polyimide) or a part of the polyamic acid component is partially dehydrated and subjected to ring closure reaction A polyamic acid solution that has been advanced to imidization) is cast and dried to produce a polyamic acid film first, followed by uniaxially and / or biaxially stretching this polyamic acid film as a precursor film, A polyimide film can be formed by performing a dehydration and ring closure reaction by heat treatment while suppressing film shrinkage. Kill. Examples of the stretching method include a tenter method and a roll method, and any stretching method that is generally used may be used.

The mechanical properties of the resulting polyimide film are governed by factors such as the type of monomer used for the polymerization, polymerization conditions, and film preparation conditions, and the like, so that the desired tensile strength and tensile modulus can be obtained. It is necessary to find out the types of monomers, polymerization conditions, film preparation conditions, and the like.

The polyimide film obtained by such a method has a thickness of 1 to 500 μm, a tensile strength of the film of 10 kgf / mm ² or more, and a tensile elasticity of the film of ² or more.
Those having a weight of 00 kgf / mm ² or more are preferable for obtaining a graphitic film having a high degree of graphitization, high elongation and toughness. A particularly preferred tensile strength of the polyimide film is 15 kgf.
/ Mm ² or more, the tensile modulus of the film is 500 kgf
/ Mm ² or more. In addition, the polyimide film has a small difference in tensile strength between the warp direction and the transverse direction of the film, and a difference in elastic modulus in each of the directions is less than 10%. Preferred for.

When the glass transition temperature of the polyimide film is lower than 350 ° C., the shrinkage of the film during the thermal decomposition process becomes extremely large, and the graphite film finally obtained contains many defects such as tears and wrinkles. Therefore, it is preferable that the glass transition temperature of the polyimide film is 350 ° C. or higher in order to obtain a high-quality graphite film without shrinkage, breakage, or the like.

The polyimide film having such characteristics has sufficient strength and elongation and does not break or break even when creased, so that it can be used for processing such as origami.
Processing can be performed. Therefore, using such a polyimide film, it is possible to fold up a three-dimensional three-dimensional structure such as a polygonal or spherical body with a complicated shape from a single film by a method generally used for origami. It is. For example, using a polyimide film having the above characteristics, a three-dimensional structure having a complicated structure such as a box, a flower, a crane, an airplane, or a balloon made of origami can be formed.

In the method for producing a graphitic molded article of the present invention, the molded article produced as described above using a homogeneous polyimide film having the above-mentioned properties and low anisotropy is in a free end state. Therefore, after applying a heat treatment at a temperature of 500 to 1000 ° C. at a heating rate of 20 ° C./min or less in an inert gas or vacuum without applying pressure to the molded body, By heat-treating at a temperature of 2500 ° C. or more, the carbonized, graphitized, graphitic molding is caused by isotropic shrinkage while maintaining a specific three-dimensional structure without being shrunk in one direction. You can get the body.

As described above, it is important to heat-treat the polyimide film molded article having the above-mentioned properties at the free end in order to maintain the complicated shape of the original polyimide film molded article to obtain a graphitic molded article. It is.

Since the obtained graphitic molded article has high elongation and toughness, it can be returned to a single sheet of film by unraveling a bent portion or the like. For example, a polyimide film can be wound in a spiral shape, and the graphite material formed under the above conditions can be returned to a single sheet of graphite film.

Next, a method for producing a graphite film of the present invention, as described above, the glass transition temperature of 350 ° C. or higher, a tensile strength of 10 kgf / mm ² or more and a tensile modulus of 200 kgf / mm ² or more Wherein the difference in the tensile strength between the warp direction and the transverse direction of the film and the difference in the elastic modulus in those directions are 1 respectively.
0% or less of the polyimide film is carbonized in an inert gas or vacuum in a free end state, and then the obtained carbonized film is heat-treated at a temperature of 2500 ° C. or more in an inert gas or vacuum.

In each of the above-mentioned methods for producing a graphite molding and a graphite film, it is preferable that the atmosphere for producing the graphite molding by a high temperature treatment of 500 ° C. or more is performed under an inert gas or vacuum. . As the inert gas, for example, argon, helium, nitrogen and hydrogen are used. In the carbonization process up to 1000 ° C, 20 ° C
Heat treatment at a heating rate of not more than / min is preferable because wrinkles and the like of the film due to rapid thermal decomposition hardly occur.

In order to bring the carbonized film closer to graphite, it is necessary to perform a further heat treatment at a temperature of 2500 ° C. or more. Means for performing the heat treatment at a temperature of 2500 ° C. or higher include high-frequency induction heating, microwave heating, and plasma arc heating. Heat treatment at a temperature exceeding 3000 ° C. has many problems in the selection of the heating method and the material of the apparatus. Further, when the treatment temperature exceeds 3500 ° C., remarkable chemical changes such as decomposition and sublimation of carbon components in the film occur, and the film may become brittle.

Graphitic film obtained by the above method
Has high heat resistance without ignition at a temperature in the air 500 ° C., it is excellent in mechanical properties.

Further, by subjecting the graphite film to a post-treatment such as rolling, the tensile strength becomes 10.0 kgf.
/ Mm ² or more and a tensile elongation of 1.5% or more. Since the film thus rolled is further enhanced in mechanical properties as described above, the processing and processing such as bending can be more easily performed, and a single graphite film can be used for origami. By a general method, a molded body having a three-dimensionally complicated shape can be machined and processed.

However, in this case, the polyimide film is susceptible to repeated bending and tends to break when subjected to fine processing. Work with
It is desirable to perform graphitization after the processing.

Further, the graphite film and the graphite molded article of the present invention have a high thermal conductivity because the graphite layer is well-developed in a direction parallel to the film surface, and have a high propagation property such as sound waves and electric conductivity. Excellent performance in gas and gas shielding properties,
Due to high tensile strength and tensile elongation, electrode materials, conductive materials, heating elements, structural materials, heat insulating materials, heat-resistant sealing materials, X-ray parts, acoustic materials, electromagnetic wave shielding materials, biocompatible materials, catalysts, electronic materials, etc. It can be widely used for industrial applications and is useful for many purposes.

Further, the molded article made of the graphite film of the present invention has a metallic luster and is flexible.
The novel design, or the graphitic film and its precursor film are useful as a novel design material.

[0039]

【Example】

[0040]

[0041]

[0042]

Comparative Example 1 4,4'-diaminodiphenyl ether (abbreviation: 4,
4'-DPE) and pyromellitic dianhydride (abbreviation:
PMDA) with N-methyl-2-pyrrolidone (abbreviation: NM)
P) An equimolar polyaddition reaction was performed in the solution to prepare a polyamic acid solution having a polymer concentration of 12% by weight. Using this polymer solution as a precursor, a continuous polyimide film having a width of 500 mm and a thickness of 50 μm was produced using a casting apparatus. The tensile strength in the length direction (vertical direction) of the film is 18 kgf / mm ² , and the tensile elastic modulus is 280 k
gf / mm ² , tensile strength in the width direction (width direction) is 17
kgf / mm ² , tensile modulus is 285 kgf / mm ²
Met. The glass transition temperature of the tensile method by thermomechanical analysis was 350 ° C. The polyimide film of length 10 m, wound graphite rods in the core end tubular shape fixed to the core of the film with a diameter of 50 mm, made of carbon fibers in a state of fixing the film to the core fabric Wrapped in high frequency
It was introduced into an induction heating furnace. Under nitrogen atmosphere, from room temperature 40
Heat up to 0 ° C at 5 ° C / min, then 2 ° C / min
After raising the temperature to 2000 ° C, switch the atmosphere to argon
The temperature is then raised to 2900 ° C at a rate of 3 ° C / min.
did. After holding at this temperature for 2 hours, the temperature is lowered at 10 ° C./min.
Cooled at warm rate.

When the film was taken out of the furnace, a graphite film having a metallic luster was obtained. However, the film was intermittently cracked due to shrinkage of the film, and the film was cut off. Could not be made into a continuous graphite film. The appearance of the film was also poor. The electrical conductivity of this film is 1.1 × 10 ⁴
S / cm.

Comparative Example 2 A polyimide film was produced by the same composition and the same method as in Comparative Example 1. The physical properties of the film were the same as in Comparative Example 1 . This polyimide film having a length of 10 m was spirally wound so as to have a diameter of 10 cm in a state of a free end having no core in the center, wrapped in a woven fabric made of carbon fiber, and introduced into a high-frequency induction heating furnace. Under a nitrogen atmosphere, the temperature was raised from room temperature to 400 ° C. at 5 ° C./min.
After raising the temperature to 2000 ° C. at a rate of 2 ° C./min , the atmosphere was switched to argon, and then the temperature was raised to 2300 ° C. at a rate of 3 ° C./min. After being kept at this temperature for 2 hours, it was cooled to room temperature at a rate of 10 ° C./min.

When the film wrapped in the carbon fiber woven fabric was taken out of the furnace, a spiral graphite-like molded product having a blackish metallic luster was obtained. The spirally wound film was brittle, and when the film was to be unwound, cracking occurred in the film, and a single continuous film could not be formed. This film had a (002) plane spacing of 3.39 as measured by wide-angle X-ray diffraction, and was slightly inferior in graphitic properties. The tensile strength is 10.0 kgf / mm ² ,
The tensile elongation was 0.8%, the electric conductivity was 500 S / cm, and as a result of elemental analysis, the carbon content was 99.0% by weight.

[Example 1 ] Paraphenylenediamine (abbreviation: PPD) and 3,3 ',
4,4'-biphenyltetracarboxylic dianhydride (abbreviation: BPDA) was subjected to an equimolar polyaddition reaction in an NMP solution to prepare a polyamic acid solution having a polymer concentration of 15% by weight. Using this polymer solution as a precursor, a continuous polyimide film having a width of 500 mm and a thickness of 50 μm was produced using a casting apparatus. The tensile strength in the length direction (vertical direction) of the film is 24 kgf / mm ² , the tensile modulus is 850 kgf / mm ² , and the width direction (width direction)
Has a tensile strength of 23 kgf / mm ² and a tensile modulus of 8
It was 65 kgf / mm ² . The glass transition temperature of the tensile method by thermomechanical analysis was 420 ° C.

From this polyimide film, one square film having a side length of 300 mm was cut out. According to the method described in "New Origami" issued by Nagaoka Shoten in 1992, a box having a size of 20 cm x 15 cm x 10 cm in height was made from this polyimide film.

The box made of the polyimide film was wrapped in a woven fabric made of carbon fiber and introduced into a high-frequency induction heating furnace. Under nitrogen atmosphere, from room temperature to 1000 ° C 2 ° C /
After raising the temperature to 2000 ° C. at a rate of 5 ° C./min, the atmosphere was switched to argon and
The temperature was raised to 2800 ° C at a rate of ° C / min. After being kept at this temperature for 2 hours, it was cooled to room temperature at a rate of 10 ° C./min. When the molded product wrapped in the carbon fiber woven fabric was taken out of the furnace, the overall size shrunk by about 20% on one side and became smaller, but a metallic glossy box-like graphite film molded product was obtained.

A test piece was cut out from the molded body as a rectangular graphite film having a length of 50 mm and a width of 5 mm, and the properties were examined. The tensile strength was 10.5 kgf / mm ² ,
Tensile elongation is 1.5%, electric conductivity is 8.9 × 10 ³ S
/ Cm. This box-shaped graphite film molded article is flexible and can be placed in a box without breaking by a small external force.
g of powder could be charged. Wide-angle X-ray diffraction showed that the (002) plane spacing of this graphite film was 3.36, and it was confirmed that the graphite film had almost a graphite structure. Also,
As a result of elemental analysis, the carbon content was 99.5% by weight.

[0051]

[0052]

[0053]

[0054]

[0055]

Example 2 Purified PPD and 3,3 ', 4,4'-tetraaminobiphenyl tetrahydrochloride (abbreviation: TABT) in a molar ratio of 9
2: 4 collected and added distilled NMP,
Stir and dissolve. Reaction temperature -10 ° C under nitrogen atmosphere
And controlled by molar ratio of PMDA: PPD: TA
PMDA was added in a solid state while keeping the temperature of the solution low so that BT = 100: 92: 4, and a polyaddition reaction was performed. After the addition, stirring was continued to prepare a uniform high-viscosity polyamic acid solution. The concentration of the polymer solution was 12% by weight.

This polyamic acid solution was applied to a casting apparatus to produce a continuous polyimide film having a width of 300 mm and a thickness of 40 μm. Tensile strength 20 kgf / mm ² in the longitudinal direction of the film (longitudinal direction), tensile modulus 900 kgf / mm ^2, a tensile strength in the width direction (transverse direction) is 19 kgf / mm ^2, tensile modulus 920k
gf / mm ² . The glass transition temperature of the tensile method by thermomechanical analysis was 440 ° C.

This polyimide film having a length of 5 m is wound into a cylindrical shape so as to have a diameter of 10 cm in a state of a free end having no core in the center portion, and is glued with a carbon fiber bundle having a diameter of 5 mm. Hanged. In a nitrogen atmosphere, the temperature was raised from room temperature to 500 ° C. at a rate of 10 ° C./min, and then at a rate of 2 ° C./min to 2000 ° C., the atmosphere was switched to argon, and then the temperature was raised at a rate of 3 ° C./min. 3000
℃. After holding at this temperature for 2 hours, 10 ° C
/ Min at room temperature.

When the film was taken out of the furnace, a spirally graphitic film molded product having a metallic luster was obtained. The spirally wound film could be rewound, and the one film that had been rewound and rolled could be processed without breaking even when bent.

The graphite film had a (002) plane spacing of 3.36 from wide-angle X-ray diffraction, confirming that it was almost a graphite structure. The tensile strength is 10kg
f / mm ² , tensile elongation 2.0%, electrical conductivity 2.
It was 0 × 10 ⁴ S / cm, and as a result of elemental analysis, the carbon content was 99.7% by weight.

Comparative Example 3 4,4'-bis (3-aminophenoxy) biphenyl (abbreviation: BAPP) and PMDA
Was subjected to an equimolar polyaddition reaction in an NMP solution to prepare a polyamic acid solution having a polymer concentration of 12% by weight. Using this polymer solution as a precursor, a continuous polyimide film having a width of 500 mm and a thickness of 50 μm was produced using a casting apparatus. The tensile strength in the length direction (vertical direction) of the film is 18 kgf / mm ² , and the tensile modulus is 285.
kgf / mm ² , tensile strength in the width direction (horizontal direction) is 1
7 kgf / mm ² , tensile modulus 265 kgf / mm
^{Was 2} . The glass transition temperature of the tensile method by thermomechanical analysis was 280 ° C.

This polyimide film having a length of 10 m is
Wrap it in a cylindrical shape around the core so that it has a diameter of 10 cm with respect to the core,
Next, by removing the core,
It was in the state of the end. The resulting cylinder is made of carbon fiber
And wrapped in a high-frequency induction heating furnace. Nitrogen atmosphere
In an atmosphere, the temperature was raised from room temperature to 400 ° C. at a rate of 5 ° C./min.
After raising the temperature to 2000 ° C. at a rate of 2 ° C./min.
The gas was switched to argon, and then the temperature was raised at a rate of 3 ° C / min.
To 2900 ° C. Let it stay at this temperature for 2 hours
After that, the mixture was cooled to room temperature at a rate of 10 ° C./min.

When the film was taken out of the furnace, the film was formed into a black mass due to fusing, and could not be rewound and could not be formed into a graphite film. In addition, the electrical conductivity of this mass could not be measured.

[0064]

The graphitic film of the present invention has a high tensile strength and tensile elongation, and can form a three-dimensionally complicated graphitic structure such as a polygonal or spherical body. . The graphite molding of the present invention can have a three-dimensional complicated shape, has high strength, and has flexibility.

Claims (8)

(57) [Claims] 1. A tensile strength of 10.0 kgf / mm ² or more, a tensile elongation of 1.5% or more, and a carbon content of 9
Graphite film of 9% by weight or more. (1) a glass transition temperature of 350 ° C. or more;
Tensile strength of 10 kgf / mm ² or more and a tensile modulus of a 200 kgf / mm ² or more polyimide film, and the difference between the vertical direction and the transverse direction of the tensile strength difference and modulus their direction of the film Are 10% each
(2) Then, the obtained carbonized film is heat-treated in an inert gas or vacuum at a temperature of 2500 ° C. or more in an inert gas or vacuum. A method for producing a graphite film. 3. A glass transition temperature of 350 ° C. or higher,
Tensile strength of 10 kgf / mm ² or more and a tensile modulus of a 200 kgf / mm ² or more polyimide film, and the difference between the vertical direction and the transverse direction of the tensile strength difference and modulus their direction of the film Are 10% each
(2) Then, the resulting carbonized film is heat-treated in an inert gas or vacuum at a temperature of 2500 ° C. or more at a temperature of 2,500 ° C. or more, Next, a method for producing a graphitic film, characterized by subjecting the obtained graphitic film to a rolling treatment. Wherein said carbonization is claim 2 or, characterized in that carbonized while raising the temperature from 500 to 1000 ° C. 20 ° C. / min with the following Atsushi Nobori rate in an inert gas or vacuum
4. The method for producing a graphitic film according to 3 . 5. A method for producing a graphitic molded body, comprising molding using the graphitic film according to claim 1 . 6. A glass transition temperature of 350 ° C. or higher,
Tensile strength of 10 kgf / mm ² or more and a tensile modulus of a 200 kgf / mm ² or more polyimide film, and the difference between the vertical direction and the transverse direction of the tensile strength difference and modulus their direction of the film Are 10% each
(2) Then, the molded body is carbonized in an inert gas or vacuum at a free end, and (3) Then, a temperature of 2500 ° C. or more A method for producing a graphitic molded body, characterized by heat-treating. 7. A graphitic molded article obtained by the production method according to claim 5 or 6 . 8. A glass transition temperature of 350 ° C. or more, a tensile strength of 10 kgf / mm ² or more, and a tensile modulus of 20
0 kgf / mm ² or more polyimide film,
A precursor film for producing a graphitic film, wherein the film is a polyimide film having a difference in tensile strength between the longitudinal direction and the transverse direction and a difference in elastic modulus in each of the directions within 10%.