JP2003206119A - Carbon foam and graphite foam and method for producing the same - Google Patents

Abstract

[Problem] To provide a carbon foam having a uniform cell structure and having properties such as heat resistance, thermal conductivity, chemical stability, electric conductivity, strength, and gas diffusibility under low pressure conditions. And a method for producing a carbon foam capable of controlling the properties of the carbon foam under low-pressure production conditions, and a graphite foam from the carbon foam and a method for producing the same. SOLUTION: A specific mesophase pitch prepared from a pitch obtained by polymerizing a condensed polycyclic hydrocarbon or a substance containing the same with hydrogen fluoride / boron trifluoride as a catalyst is used as a raw material at 400 ° C. A carbon foam produced under a pressure of 5 MPa or less of an inert gas when producing a carbon foam by heat treatment at the above temperature, and a graphite foam and a carbon foam which are heat treated at a temperature of 2000 ° C. or more; Manufacturing method of graphite foam.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a carbonaceous or graphitic carbon material which is made of mesophase pitch as a raw material and which has excellent heat resistance and chemical stability and has a uniform cell structure.

[0002]

2. Description of the Related Art Carbon foams having various unprecedented properties such as heat resistance, thermal conductivity, chemical stability, electrical conductivity, strength and gas diffusivity have been investigated. Since conventional thermosetting resin-based foams form non-graphitizable carbon, they have low oxidation resistance at high temperatures, low corrosion resistance to chemical reactions, and insufficient thermal conductivity.

As a material meeting these requirements, a novel foam material having high chemical stability, heat resistance and oxidation resistance, which is produced by heat-treating mesophase pitch under pressure with an inert gas, has been proposed ( Preparat
ion, structure and application of mesophase pitche
s prepared from aromatic hydrocarbons using HF / BF3
as catalysts "TANSO 1992 [155] 370-378, I. Mochi
da, Y. Korai, K. Shimizu, SH. Yoon, R. Fujiur
a.). Further, the inventors of the present invention, in Japanese Patent Application No. 2001-13987, heat-treat a specific mesophase pitch at a temperature of 400 ° C. to 500 ° C. under a pressure of 0.1 MPa or more by an inert gas, thereby obtaining a uniform and open-cell cell. It is proposed that a specific carbon foam having a structure can be industrially produced more stably.

US Pat. No. 6,033,506 also discloses that the mesophase pitch pitch is 1000 psi (about 6.8MPa) with an inert gas.
A method of producing carbon foam by heat treatment under pressure in a) is disclosed.

[0005]

As described above, it has been found that a foam material can be produced by heat treating the mesophase pitch under the pressure of an inert gas.
Further, it has been clarified in Japanese Patent Application No. 2001-13987, for example, that the pressurizing pressure at the time of heat treatment is dominant as an operating condition for controlling the bulk density of the foam and the size of the cell. That is, it was necessary to make the pressurizing pressure very high in order to increase the bulk density of the foam.

However, at a high temperature of 500 ° C. or higher,
For example, in order to carry out heat treatment under a high pressure condition of 6 MPa or more, a special reactor capable of withstanding high temperature and high pressure is required, which makes it difficult to industrially produce foam at a low cost, and it is difficult to produce carbon foam under low pressure conditions. There is a demand to control properties such as bulk density.

An object of the present invention is to have a uniform cell structure,
Providing carbon foam having properties such as heat resistance, thermal conductivity, chemical stability, electrical conductivity, strength and gas diffusivity under low pressure conditions, and controlling the properties of the above carbon foam under low pressure manufacturing conditions. The present invention provides a method for producing a carbon foam that can be used. A further object of the present invention is to graphitize the carbon foam at 2000 ° C. or higher to provide a graphite foam having a uniform and open-cell cell structure and at the same time a high graphitization degree in an industrially stable manner. There is.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that condensed polycyclic hydrocarbons or substances containing them are polymerized using hydrogen fluoride / boron trifluoride as a catalyst. By using a specific mesophase pitch prepared from the pitch obtained by the above as a raw material, the pressurizing pressure of the inert gas when heat-treating at a temperature of 400 ° C. or higher to produce carbon foam is 5 MPa or less, preferably 4 MPa or less, Further, it has been found that a good carbon foam having a bulk density of 0.20 g / cm ³ or more can be produced even at 3 MPa or less. Further, by subjecting this carbon foam to a heat treatment at a temperature of 2000 ° C. or higher, the bulk density becomes 0.30 g / cm 3.
The inventors have found that a graphite foam having a size of ³ or more can be stably produced, and have completed the present invention.

That is, the mesophase pitch used in the present invention is obtained by (1) polymerizing a condensed polycyclic hydrocarbon or a substance having the same with hydrogen fluoride / boron trifluoride as a catalyst, and removing the catalyst. Maximum processing temperature after 30
A mesophase pitch having an aromatic carbon index fa value of 0.90 to 0.97, which is obtained by heat treatment in a temperature range of 0 ° C. to 500 ° C., (2) a condensed polycyclic hydrocarbon or a substance having the same, The catalyst molar ratio (condensed polycyclic hydrocarbon / hydrogen fluoride / boron trifluoride) when polymerizing with hydrogen fluoride / boron trifluoride as a catalyst is hydrogen fluoride / condensed polycyclic hydrocarbon = 0. 2 to
1.0, boron trifluoride / condensed polycyclic hydrocarbon = 0.01-
0.1, the reaction temperature is 100-350 ℃, obtained by polymerization under conditions, after removing the catalyst, the maximum treatment temperature 300 ℃ ~
Mesophase pitch obtained by heat treatment in the temperature range of 500 ° C, (3) condensed polycyclic hydrocarbon or a substance having the same is polymerized under the reaction conditions described in (2) above, and after removing the catalyst, the maximum treatment is performed. A fa value of 0.90 to 0.97 obtained by heat treatment in a temperature range of 400 ° C to 500 ° C,
When solvent-extracted pitch synthesized from a mesophase pitch having a softening point of 300 ° C or less as determined by a flow tester, (4) condensed polycyclic hydrocarbon or a substance containing it using hydrogen fluoride / boron trifluoride as a catalyst Is a mesophase pitch having a softening point of 250 ° C. or higher as obtained by the flow tester.

In the present invention, the above mesophase pitch is 0.1 to 5 MPa, preferably 0.1 to 4 MPa, and more preferably 0.1 to 3 MPa by an inert gas.
The present invention relates to a carbon foam obtained by heat-treating at a temperature of 400 to 800 ° C. under pressure, a method for producing the carbon foam, a graphite foam obtained by heat-treating the carbon foam at a temperature of 2000 ° C. or more, and a method for producing the same. .

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a synthetic mesophase pitch obtained by polymerizing a condensed polycyclic hydrocarbon or a substance containing the same in the presence of hydrogen fluoride / boron trifluoride is used as a raw material. To be Since the petroleum-based and coal-based mesophase pitches that have been known for a long time are derived from by-products, it is difficult to precisely control the physical properties of the mesophase pitch to be carried out in the present invention, which is inferior in the stability of properties, and also metal. It is not preferable because there are many impurities such as impurities.

0.1-5 MPa, preferably 0.1-4
The specific pitch used for obtaining the carbon foam, which is obtained by heat treatment under a pressure of an inert gas of MPa, more preferably 0.1 to 3 MPa, includes (1) a condensed polycyclic hydrocarbon or a polycondensed hydrocarbon containing the same. After the substance is polymerized with hydrogen fluoride / boron trifluoride as a catalyst and the catalyst is removed, the maximum treatment temperature higher than the usual post-treatment temperature condition 30
Method of heat treatment in a temperature range of 0 ° C to 500 ° C, (2) Reaction conditions (temperature, catalyst) for polymerizing a condensed polycyclic hydrocarbon or a substance containing the same with hydrogen fluoride / boron trifluoride as a catalyst The maximum processing temperature is 300 ° C-5
Method of heat treatment at 00 ° C., (3) Polymerization of condensed polycyclic hydrocarbon or a substance having the same under the reaction conditions described in (2) above, after removing the catalyst, the maximum treatment temperature is 400 ° C. to 5 ° C.
Heat treatment in the temperature range of 00 ° C., fa value of 0.90
0.97, the softening point determined by a flow tester is 300
Method for obtaining mesophase pitch below ℃, (4) Solvent extraction residue of pitch obtained by polymerizing condensed polycyclic hydrocarbon or substances containing it with hydrogen fluoride / boron trifluoride as catalyst Can be manufactured by any of the following methods. The mesophase pitch has a bulk density of 0.20 g.
Suitable for the production of carbon foams with a / cm ³ or more.

In the method for obtaining mesophase pitch by heat treatment after the reaction described in (1) above, condensed polycyclic hydrocarbons are polymerized under autogenous pressure by a catalyst and then depressurized to recover the catalyst, and the maximum treatment temperature is 300 It is performed by heat treatment at a temperature of ℃ or more. At this time, an inert gas such as nitrogen may be blown in as in the case of the usual light components removal operation. Alternatively, the light component may be removed, the obtained pitch may be once taken out, and heat treatment may be performed at a maximum treatment temperature of 300 to 500 ° C. in an inert atmosphere. The obtained aromatic carbon index fa value is 0.9.
The mesophase pitch of 0 to 0.97 is converted to 0.1 to 5 MPa, preferably 0.1 to 4 MP by an inert gas.
a, more preferably 40 under a pressure of 0.1 to 3 MPa.
By performing heat treatment at a temperature of 0 ° C. to 800 ° C., carbon foam having a bulk density of 0.20 g / cm ³ or more can be obtained. When the pitch has an aromatic carbon index fa of more than 0.97, it is estimated that the amount of the aliphatic hydrogen effective as a foaming agent is small, and a good cell structure cannot be formed. On the other hand, except when a pitch polymerized under a specific catalyst condition described below is used, a pitch having an aromatic carbon index fa of less than 0.90 has a bulk density of 0.20 g / in a pressure of 3 MPa or less by an inert gas. It is difficult to produce carbon foam with a size of ³ cm ³ or more. The method of changing the reaction conditions (temperature, catalyst molar ratio) in the above (2) depends on the size of the reactor and the charged amount, but the ratio of boron trifluoride in the catalyst to the molar ratio of naphthalene to 0.
It is effective to reduce the amount to 1 or less, and the catalyst molar ratio (condensed polycyclic hydrocarbon / hydrogen fluoride / boron trifluoride) during polymerization is
Polymerization under the conditions of hydrogen fluoride / condensed polycyclic hydrocarbon = 0.2 to 1.0, boron trifluoride / condensed polycyclic hydrocarbon = 0.01 to 0.1, reaction temperature 100 to 350 ° C. Then, after removing the catalyst, heat treatment is performed at a maximum processing temperature of 300 ° C. to 500 ° C. Under these reaction conditions,
In some cases, a mesophase pitch having an aromatic carbon index of 0.90 to 0.97 cannot be obtained.
A carbon foam having a bulk density of 0.20 g / cm ³ or more can be produced even under a pressure of MPa. Further, in the above method (3), the polymerization is conducted under the above catalyst conditions, and the heat treatment after removing the catalyst is performed at the maximum treatment temperature of 400 ° C to 500
Performed at a higher temperature of ℃, which is advantageous for improving the foam bulk density f
Even when a mesophase pitch having an a value of 0.90 to 0.97 was manufactured, the softening point determined by the flow tester was 3
The temperature is not higher than 00 ° C, the meltability can be maintained, and it is suitable for producing a carbon foam having an arbitrary shape using a mold. Also,
There is also a method in which after the polymerization is carried out at a reaction temperature of 200 ° C. or lower, most of the catalyst is removed to reduce the catalyst ratio, and the reaction is further continued at a reaction temperature of 200 ° C. or higher to obtain a synthetic pitch.

In the method (4) using the solvent extraction residue of synthetic pitch, various solvents such as hexane, benzene, toluene, pyridine, quinoline, chloroform, and tar washing oil are used as the extraction solvent. The mesophase pitch obtained from the extraction residue is 0.1 to 5 MPa, preferably 0.1 to 4 MPa, more preferably 0.1 to 3 MP.
A bulk density of 0.20 g / cm ³ by heat treatment at a temperature of 400 ° C. to 800 ° C. under pressure with an inert gas of a.
The above carbon foam can be manufactured.

As a method of charging mesophase pitch in a pressure vessel, (A) a method of charging powder, pellets or lumpy mesophase pitch into a metal vessel such as aluminum or stainless steel for forming a foam, (B)
The mesophase pitch is placed in a metal container such as aluminum or stainless steel and charged into a heating furnace, and the mesophase pitch is maintained at a temperature of softening point plus about 100 ° C. for about 10 hours in a non-oxidizing atmosphere of a nitrogen gas flow to obtain the mesophase pitch. Examples of the method include a method of forming a uniform lump containing almost no bubbles in a metal container, a method of crushing (C) pitch, molding at room temperature or under heating, and then charging the container in a container made of aluminum or stainless steel.

In the method of (C), after crushing the pitch and molding at room temperature or under heating, and then charging into a container, the softening point of the raw material mesophase pitch satisfying the parameters of the present invention becomes high, and almost all the bubbles are contained in the metal container. It is effective to obtain a uniform carbon foam when it is difficult to form a uniform mass.

The above-mentioned specific pitch is 0.1 to 5 MP
a, preferably 0.1 to 4 MPa, more preferably 0.1 to 3 MPa under pressure with an inert gas at 400 ° C.
The method of heat treatment at a temperature of up to 800 ° C. is not particularly limited, but the following procedure may be adopted, for example.

Add a metal container containing mesophase pitch
It is charged in a heatable pressure vessel and the inside is nitrided by vacuum replacement.
After changing to the basic atmosphere, at atmospheric pressure at a rate of 3 ° C / min
The temperature is raised to 350 ° C. and kept for 1 hour. Then 350
While maintaining at ℃, pressurize to 3.0MPa with nitrogen, and
The temperature is raised to 550 ° C. at a rate of ° C./min. 1 hour as it is
After holding, turn off the heater and let it cool naturally in the furnace,
Remove the sample and place it in a metal container as described above.
Bulk density with uniform cell structure 0.20 g / cm ^ThreeMore than
Carbon foam is formed. In addition, due to inert gas
The pressurization may start at room temperature.

Depending on the application, the carbon foam obtained can be subsequently heat treated at a temperature above 600 ° C. and below 2000 ° C. The pressure at this time may be normal pressure or increased pressure. By applying the above heat treatment, the density, electrical properties or thermal properties can be controlled within an appropriate range.

Further, the carbon foam is heat-treated at a temperature of 2000 ° C. or higher and graphitized to produce a graphite foam having a bulk density of 0.3 g / cm ³ or higher. Before graphitizing, it is more preferable to perform heat treatment (calcination) in advance at a temperature of 800 ° C. or higher and lower than 2000 ° C. The graphite foam having such specific physical property values can be a foam having high strength and high thermal conductivity.

[0021]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to these examples. The pitch analysis method and analysis conditions in this example are described below.

(Elemental analysis) In order to calculate the atomic ratio of hydrogen to carbon (hereinafter, simply referred to as (H / C)), simultaneous analysis of carbon, nitrogen and hydrogen was performed by using PerkinElmer (PERKINELMER) as an analyzer. 2400CHN-type elemental analyzer manufactured by K.K. 1.5 ± 0.2 mg of sample pitch in a tin container
After weighing and setting in the apparatus, it was burned at a temperature of 975 ° C. for 5 minutes, and detected by TCD by He gas carrier and measured. In the measurement of the sample, it was corrected in advance with acetanilide (2.0 ± 0.1 mg) as a standard substance.

To 100 parts of (FT-IR) KBr powder, 1 part of modified pitch powder was added and mixed in an agate mortar, and then FT / IR-41 manufactured by JASCO Corporation.
0, the diffuse reflection method measuring device DR-81 was set for measurement. The obtained diffuse reflectance spectrum was analyzed by Kubelka.
-3050 on the spectrum obtained by the Munk transform
cm ^-1 vicinity of the peak intensity of the (absorption intensity of the aromatic C-H stretching vibration = Daromatic), the absorption intensity of a peak intensity at around 2930 cm ^-1 (aliphatic C-H stretching vibration = Daliphati
The ratio (Daromatic / Daliphatic) to c) was determined.

Example 1 Super Strong Acid Catalyst HF-BF ₃ (Catalyst Molar Ratio: Naphthalene / H
F / BF ₃ = 1 / 0.35 / 0.15) in the presence of naphthalene at a reaction temperature of 270 ° C. under autogenous pressure,
The pressure was dropped to recover the catalyst, and nitrogen was blown at 350 ° C. for 10 hours to remove light components to obtain a mesophase pitch having a softening point of 230 ° C. measured by a flow tester. By further heat-treating the mesophase pitch at 470 ° C. for 0.5 hour, the softening point by a flow tester is 295 ° C.,
(H / C) is 0.526, (Daromatic / Daliphati
c) is 1.341, aromatic carbon index fa value is 0.929
The heat-treated mesophase pitch which is is obtained.

8 g of the heat-treated mesophase pitch was used as the inner diameter 3
It was placed in a cylindrical aluminum container (internal volume of 30.175 cm ³ ) having a diameter of 1 mm and a depth of 40 mm, and was placed in an SUS closed container having an outer diameter of 50 mm, an inner diameter of 35 mm and a length of 450 mm. This SUS closed container was placed in the center of a crucible furnace with an inner diameter of 55 mm and equipped with a temperature controller, and the inside was changed to a nitrogen atmosphere by vacuum substitution. Then, at atmospheric pressure, 3
The temperature was raised to 350 ° C. at a rate of ° C./minute, the temperature was maintained for 1 hour, and then, the pressure was increased to 3.0 MPa. The temperature was raised to 550 ° C. at a rate of 2 ° C./min and maintained for 1 hour while maintaining 3 MPa, the heater was turned off, the SUS closed container was naturally cooled in the furnace, and then the sample was taken out. Pitch was foamed and carbonized in the aluminum container to form carbon foam. Bulk density of carbon foam in aluminum container is 0.36 g / cm
It was ³ .

The carbon foam was heated in a nitrogen atmosphere at 10 ° C./hour, reached 1000 ° C., and held for 2 hours for calcination. Subsequently, the temperature was raised at 500 ° C./hour in an argon atmosphere and graphitization treatment was performed at 2800 ° C. for 1 hour to prepare a graphite foam. The bulk density of the graphite foam is 0.47 g /
It was cm ³ . The results are shown in Table 1.

Example 2 The same mesophase pitch as that used in Example 1 was used.
By heat treatment at 75 ° C for 0.5 hours, the softening point by the flow tester is 300 ° C or higher, and (H / C) is 0.4.
92, (Daromatic / Daliphatic) was 1.806, and a heat-treated mesophase pitch having an aromatic carbon index fa value of 0.947 was obtained.

The heat-treated mesophase pitch was crushed with a coffee mill, and 8 g of the heat-treated mesophase pitch was pressure-molded into a disk shape having a diameter of 28 mm and a thickness of 13 mm at 3 MPa to obtain a bulk density of about 1.1 g / cm.
A pitch molded body of No. ³ was prepared. Inner diameter of the pitch compact 3
It was placed in a cylindrical aluminum container (internal volume 30.175 cm ³ ) having a depth of 1 mm and a depth of 40 mm, charged into the SUS closed container used in Example 1, and after changing the inside to a nitrogen atmosphere by vacuum substitution, The pressure was increased to 3.0 MPa at room temperature. 550 at a rate of 2 ° C./min while maintaining 3 MPa
The temperature was raised to 0 ° C. and the temperature was maintained for 1 hour to produce a carbon foam. The bulk density of the carbon foam was 0.50 g / cm ³ . The results are shown in Table 1.

The carbon foam was heated in a nitrogen atmosphere at 10 ° C./hour to reach 1000 ° C. and held for 2 hours for calcination. Subsequently, the temperature was raised at 500 ° C./hour in an argon atmosphere and graphitization treatment was performed at 2800 ° C. for 1 hour to prepare a graphite foam. The bulk density of the graphite foam is 0.62 g /
It was cm ³ . The results are shown in Table 1.

Example 3 Super Strong Acid Catalyst HF-BF ₃ (Catalyst Molar Ratio: Naphthalene / H
F / BF ₃ = 1 / 0.32 / 0.074) was used to polymerize naphthalene at a reaction temperature of 245 ° C. under autogenous pressure.
The pressure was dropped to recover the catalyst, and nitrogen was blown at 350 ° C. for 20 hours to remove light components to obtain mesophase pitch. The flow tester of the mesophase pitch has a softening point of 220 ° C., (H / C) of 0.590, and (Daromatic
/ Daliphatic) was 0.576 and the aromatic carbon index fa value was 0.863.

When a carbon foam was produced under the same conditions as in Example 1, the carbon foam obtained had a bulk density of 0.2.
It was 5 g / cm ³ .

The carbon foam was heated in a nitrogen atmosphere at 10 ° C./hour to reach 1000 ° C. and held for 2 hours for calcination. Subsequently, the temperature was raised at 500 ° C./hour in an argon atmosphere and graphitization treatment was performed at 2800 ° C. for 1 hour to prepare a graphite foam. The bulk density of the graphite foam is 0.35 g /
It was cm ³ . The results are shown in Table 1.

Example 4 After polymerizing naphthalene under the same conditions as in Example 3, the pressure was dropped to recover the catalyst, and nitrogen was blown into the catalyst at 350 ° C. for 2 hours to give a mesophase pitch having an anisotropic content of 70%. Got By heat-treating the pitch at 450 ° C. for 1 hour, the softening point by the flow tester is 234 ° C., (H /
A heat-treated mesophase pitch having a C) of 0.550, a (Daromatic / Daliphatic) of 1.68 and an aromatic carbon index fa value of 0.937 was obtained. When a carbon foam was produced under the same conditions as in Example 1, the bulk density was 0.28 g.
A carbon foam of / cm ³ was obtained.

The carbon foam was heated in a nitrogen atmosphere at 10 ° C./hour to reach 1000 ° C. and held for 2 hours for calcination. Subsequently, the temperature was raised at 500 ° C./hour in an argon atmosphere and graphitization treatment was performed at 2800 ° C. for 1 hour to prepare a graphite foam. The bulk density of the graphite foam is 0.36 g /
It was cm ³ . The results are shown in Table 2.

Example 5 The same mesophase pitch used in Example 1 was ground in a coffee mill and solvent extracted with a Soxhlet extractor in toluene solvent. The extraction residue has a softening point of 300 ° C or higher by a flow tester, (H / C) of 0.621,
The extracted mesophase pitch had a (Daromatic / Daliphatic) of 0.596 and an aromatic carbon index fa value of 0.858.

The extracted mesophase pitch powder has an inner diameter of 31
mm into a cylindrical aluminum container having a depth of 40 mm (internal volume of 30.175 cm ³ ), charged into the SUS closed container used in Example 1, and after changing the inside to a nitrogen atmosphere by vacuum replacement, The pressure was increased to 3.0 MPa at room temperature. 550 ° C at a rate of 2 ° C / min while maintaining 3 MPa
When the temperature was raised to 1 hour and held for 1 hour to produce a carbon foam, the bulk density of the carbon foam was 0.26 g / cm ³ . The carbon foam was heated at 10 ° C./hour in a nitrogen atmosphere, and after reaching 1000 ° C., it was held for 2 hours for calcination. Subsequently, the temperature was raised at 500 ° C./hour in an argon atmosphere and graphitization treatment was performed at 2800 ° C. for 1 hour to prepare a graphite foam. The bulk density of the graphite foam is 0.34 g / c
It was m ³ . The results are shown in Table 2.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

As described above in detail, by using the raw material pitch according to the present invention, a cell structure of uniform and open cells can be obtained at a pressure within the industrially stable operation range of 5 MPa or less. A carbon foam having
Further, by graphitizing the carbon foam at 2000 ° C. or higher, a graphite foam having a uniform and open cell structure and a high degree of graphitization can be produced industrially and stably.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Ryuji Fujiura             22 Wadai, Tsukuba City, Ibaraki Mitsubishi Gas Chemical             Research Institute, Inc. F-term (reference) 4G046 CA04 CA07 CB01 CB05 CB10                       CC02 CC03 EA02 EA03 EB02                       EB04 EC01 EC05

Claims (10)

[Claims] 1. A condensed polycyclic hydrocarbon or a substance having the same is polymerized by using hydrogen fluoride / boron trifluoride as a catalyst, and after removing the catalyst, heat treatment is carried out at a maximum treatment temperature of 300 to 500 ° C. The mesophase pitch having an aromatic carbon index fa value of 0.90 to 0.97 obtained by the above is heated to 400 ° C. to 8 ° C. under a pressure of 0.1 to 5 MPa with an inert gas.
A carbon foam obtained by heat treatment at a temperature of 00 ° C. (The aromatic carbon index fa is calculated from the following formula (1). Fa = 1− (H / C) / x (1+ (Daromatic / Daliphatic) × (εaliphatic / εaromatic)) (1) (H / C) is the atomic ratio of hydrogen to carbon in the pitch, and x is the average number of hydrogen bonds other than aromatic carbon (=
2), (Daromatic / Daliphatic) is FT-I
Absorption intensity of aromatic CH stretching vibration measured by R (Darom
atic) and the absorption intensity of aliphatic C-H stretching vibrations (Daliphati
c) ratio, εaliphatic / εaromatic is the specific extinction coefficient (= 2
It is). ) 2. When polymerizing a condensed polycyclic hydrocarbon or a substance having the same with hydrogen fluoride / boron trifluoride as a catalyst, a catalyst molar ratio (condensed polycyclic hydrocarbon / hydrogen fluoride / trifluoride) is used. Boron fluoride) is hydrogen fluoride / condensed polycyclic hydrocarbon = 0.2 to
1.0, boron trifluoride / condensed polycyclic hydrocarbon = 0.01-
0.1, the polymerization temperature was 100 to 350 ° C, and after removing the catalyst, the maximum treatment temperature was 300 ° C to
A carbon foam characterized by being obtained by heat-treating mesophase pitch obtained by heat treatment in a temperature range of 500 ° C. at a temperature of 400 ° C. to 800 ° C. under a pressure of 0.1 to 5 MPa with an inert gas. 3. A condensed polycyclic hydrocarbon or a substance having the same is polymerized under the reaction conditions according to claim 2, the catalyst is removed, and then heat treatment is performed at a maximum treatment temperature of 400 to 500 ° C. The obtained mesophase pitch having an fa value of 0.90 to 0.97 and a softening point determined by a flow tester of 300 ° C. or lower was treated with an inert gas in an amount of 0.1 to 5M.
A carbon foam obtained by heat treatment at a temperature of 400 ° C. to 800 ° C. under a pressure of Pa. 4. Mesophase pitch obtained as a residue when solvent-extracted pitch synthesized from condensed polycyclic hydrocarbon or a substance containing the same using hydrogen fluoride / boron trifluoride as a catalyst Carbon foam obtained by heat treatment at a maximum treatment temperature of 400 ° C. to 800 ° C. under a pressure of 1 to 5 MPa. 5. The carbon foam according to claim 1, which has a bulk density of 0.20 g / cm ³ or more. 6. A carbon foam obtained by further heat-treating the carbon foam according to any one of claims 1 to 4 at a temperature of 600 ° C. or more and less than 2000 ° C. 7. When producing the carbon foam according to any one of claims 1 to 4, after the ground mesophase pitch is molded at room temperature or under heating, under a pressure of 0.1 to 5 MPa with an inert gas. A method for producing a carbon foam, characterized in that the heat treatment is performed at a temperature of 400 ° C to 800 ° C. 8. A method for producing carbon foam, further comprising heat-treating the carbon foam according to claim 1 at a temperature of 600 ° C. or higher and lower than 2000 ° C. 9. A bulk density of 0.30 g / c, which is obtained by heat-treating the carbon foam according to any one of claims 1 to 4 and 7 at a temperature of 2000 ° C. or higher.
Graphite foam that is m ³ or more. 10. A method for producing a graphite foam, which comprises heat-treating the carbon foam according to any one of claims 1 to 4 and 7 at a temperature of 2000 ° C. or higher.