WO2007058299A1

WO2007058299A1 - Composite material

Info

Publication number: WO2007058299A1
Application number: PCT/JP2006/322972
Authority: WO
Inventors: Takayuki Tsukada; Jiayi Shan; Jin Chen
Original assignee: Bussan Nanotech Research Institute Inc.
Priority date: 2005-11-18
Filing date: 2006-11-17
Publication date: 2007-05-24
Also published as: JP2007138338A

Abstract

Disclosed is a composite material which has a backbone structure formed by binding carbon fiber structures through a carbon in a three-dimensional manner. In the composite material, each carbon fiber structure has a three-dimensional network structure formed with carbon fibers having an outer diameter of 15 to 100 nm and has a particulate part which binds up the carbon fibers in such a state where the carbon fibers are extended from the particulate part, and the particulate part is formed in the growing process of the carbon fibers. In a void formed in the backbone structure, a resin, a rubber, a metal or a carbon-containing material is impregnated. The composite material takes full advantages of the specific properties of the microfine carbon fiber.

Description

Specification

Composite material

Technical field

The present invention relates to a composite material using fine carbon fibers (so-called carbon nanotubes).

Background art

[0002] Conventionally, there has been proposed a resin composition, so-called composite material, to which desired characteristics (for example, conductivity, mechanical characteristics, etc.) are imparted by blending a filler such as carbon black with the resin. Yes.

[0003] In recent years, fine carbon fibers have been used in place of carbon black, which has been used in the past, in order to impart even better electrical conductivity and mechanical properties to a molded body formed of a composite material. Attempts have been made to blend (V, so-called carbon nanotubes). The graphite layer constituting carbon nanotubes is a substance that usually has an ordered six-membered ring arrangement structure, and has stable electrical, chemical, mechanical, and thermal properties along with its unique electrical properties. Therefore, for example, such fine carbon fibers are dispersed and blended in solid materials such as various types of resin, ceramics, metals, etc., or liquid materials such as fuel oils, lubricants, etc. to make use of the physical properties as described above. If possible, it is expected that an excellent composite material can be provided.

[0004] Specifically, for example, Patent Documents 1 and 2 propose composite materials containing carbon nanotubes in a matrix. Further, in Patent Document 3, when carbon nanotubes are blended in a resin composition, aggregates are formed by carbon nanotubes that are not simply blended with carbon nanotubes as they are, or entangled with each other. It is also known to form things and blend them.

Patent Document 1: Japanese Patent No. 2641712

Patent Document 2: Japanese Unexamined Patent Publication No. 2003-12939

Patent Document 3: Japanese Patent No. 3034027

Disclosure of the invention Problems to be solved by the invention

[0005] However, in the conventional composite materials represented by the above-mentioned documents, the excellent characteristics of fine carbon fibers (carbon nanotubes) have not been fully utilized, and fine carbon There was room for improvement of the fiber itself.

[0006] The present invention is an invention made in such a situation, and a main object is to provide a novel skeletal structure and a composite material that make the most of the unique properties of fine carbon fibers. .

Means for solving the problem

[0007] In order to solve the above problems, the present inventors have intensively studied, and in order to impart various properties such as conductivity and strength properties to the composite material, the finest possible carbon A structure in which fibers are firmly bonded to each other without being separated from each other, and each of the carbon fibers constituting the structure has few defects as much as possible. The present inventors have found that it is effective to use a skeletal structure bonded in three dimensions and to impregnate voids formed in the skeleton structure with a resin or the like, and have reached the present invention. It is.

[0008] That is, the present invention that solves the above problems is a three-dimensional network formed by carbon fiber cables having an outer diameter of 15 to: LOOnm, and a plurality of the carbon fibers extend. The carbon fiber has a granular part for bonding the carbon fibers to each other, and the granular part is formed by three-dimensionally bonding a carbon fiber structure formed in the carbon fiber growth process with carbon. It is a skeleton structure characterized by the above.

[0009] Further, the skeleton structure may contain boron!

[0010] The boron content may be 0.001 to 10 mass% with respect to the skeleton structure.

[0011] Further, the carbon fiber structure may have an area-based circle-equivalent mean diameter of 50 to 500 m.

[0012] Further, the skeletal structure is not more than I / \ 1S1.4 measured by Raman spectroscopy.

D G

And I

G '/ \ may be 1.5 or less.

G

[0013] The skeletal structure may have a bulk density of 0.2 to 2.3 gZcm ³ . [0014] The skeleton structure may have a combustion start temperature in air of 700 ° C or higher! /

[0015] In addition, the particle diameter of the granular portion may be larger than the outer diameter of the carbon fiber at the bonding position of the carbon fibers.

[0016] Further, the carbon fiber structure may be produced using at least two carbon compounds having different decomposition temperatures as a carbon source.

[0017] In addition, the present invention that solves the above problems is a three-dimensional network formed by carbon fiber cables having an outer diameter of 15 to: LOOnm, and in a mode in which a plurality of the carbon fibers extend, The carbon fiber structure has a granular part for bonding carbon fibers to each other, and the granular part is formed by joining carbon fiber structures formed in the carbon fiber growth process in three dimensions with carbon. And a void formed inside the skeleton structure is impregnated with resin, rubber, metal, or carbon-based material.

[0018] The skeleton structure may contain boron.

[0019] The boron content may be 0.001 to 10 mass% with respect to the skeleton structure.

[0020] Further, the carbon fiber structure may have an area-based circle equivalent average diameter of 50 to 500 m.

[0021] Further, the skeletal structure is measured by Raman spectroscopy. I / \ 1S 1.4

D G or less and I is 1.5 or more

It may be under G '/ \.

G

[0022] The skeleton structure may have a bulk density of 0.2 to 2.3 gZcm ³ .

[0023] The skeleton structure may have a combustion start temperature in air of 700 ° C or higher! /

[0024] In addition, the particle diameter of the granular portion may be larger than the outer diameter of the carbon fiber at the bonding position of the carbon fiber.

[0025] Further, the carbon fiber structure may be produced using at least two carbon compounds having different decomposition temperatures as a carbon source.

The invention's effect [0026] In the present invention, the skeletal structure force that becomes the framework of the composite material As described above, the fine-diameter carbon fiber force arranged in a three-dimensional network shape The granular portion formed in the growth process of the carbon fiber The carbon fiber structure itself has a structure in which the carbon fiber structure having a shape in which a plurality of the carbon fibers extend is bonded in three dimensions with carbon. In addition to the three-dimensional expansion, the carbon fiber structures are further bonded in three dimensions, so that a skeletal structure with an unprecedented expansion can be obtained, and the conductive properties of the fine carbon fibers. It is possible to fully exhibit the properties, mechanical properties and heat conduction properties.

[0027] In addition, since carbon fibers originally having a three-dimensional network shape are used as starting materials, unlike the aggregates that are forcibly created by applying external force as in the past, there is no defect in each carbon fiber. ! / ヽ is also a feature of the present invention, and this feature can also improve electrical conductivity, mechanical properties, and heat conduction properties.

[0028] Furthermore, in the present invention, when boron is contained in the skeletal structure, high conductivity can be obtained even if the structure contains a few defects.

Brief Description of Drawings

[0029] FIG. 1 is a SEM photograph of an intermediate of a carbon fiber structure used in the skeleton structure of the present invention.

FIG. 2 is a TEM photograph of an intermediate of a carbon fiber structure used in the skeleton structure of the present invention.

FIG. 3 is an SEM photograph of a carbon fiber structure used in the skeleton structure of the present invention.

FIG. 4 is a drawing showing a schematic configuration of a production furnace used for producing a carbon fiber structure in an example of the present invention.

Explanation of symbols

[0030] 1 Generation furnace

2 Introduction nozzle

3 Collision

4 Source gas supply port

a Inner nozzle inner diameter

b Inner diameter of the generating furnace

c Inner diameter of collision part d Distance from the top of the generator to the raw material gas inlet

e Raw material mixed gas introduction loca Distance to the bottom of the collision part

f Distance from the raw material gas inlet to the bottom of the generator

BEST MODE FOR CARRYING OUT THE INVENTION

[0031] Hereinafter, the present invention will be described in detail based on preferred embodiments.

The composite material of the present invention is composed of a skeleton structure composed of a carbon fiber structure and a resin, rubber, metal, or carbon-based material impregnated in a void formed inside the skeleton structure. The

First, the skeletal structure that is one of the features of the present invention will be described.

The skeletal structure is formed by bonding carbon fiber structures in three dimensions with carbon.

[0033] Here, the carbon fiber structure used in the present invention is composed of carbon fibers having an outer diameter of 15 to: LOOnm as seen in, for example, the SEM photograph shown in FIG. 1 or the TEM photograph shown in FIG. The carbon fiber structure is a three-dimensional network-like carbon fiber structure, and the carbon fiber structure has a granular portion that binds the carbon fibers to each other in a form in which a plurality of the carbon fibers extend! This is a carbon fiber structure.

[0034] The carbon fiber constituting the carbon fiber structure has an outer diameter in the range of 15 to LOONm. When the outer diameter is less than 15 nm, the carbon fiber has a polygonal cross section as described later. However, on the other hand, the smaller the diameter of the carbon fiber, the greater the number per unit amount, and the longer the length of the carbon fiber in the axial direction, resulting in higher conductivity. Having a diameter is because it is not suitable as a carbon fiber structure to be arranged as a modifier or additive in a matrix such as rosin. In particular, the outer diameter of the carbon fiber is more preferably in the range of 20 to 70 nm. This outer diameter range, in which cylindrical dalafen sheets are laminated in the direction perpendicular to the axis, that is, a multilayer, is difficult to bend and is elastic, that is, has the property of returning to its original shape after deformation. Because.

[0035] It should be noted that when annealing is performed at 1800 ° C or higher, the surface spacing of the laminated graph ensheets is reduced and the true density is increased, and the carbon fiber has a polygonal axial cross section. Laminating direction and face of cylindrical graphene sheet constituting carbon fiber Bending rigidity (EI) is improved because it is dense and has few defects in both directions.

[0036] It is desirable that the fine carbon fiber has an outer diameter that changes along the axial direction. If the outer diameter of the carbon fiber is constant and changes along the axial direction in this way, it is considered that when carbon fiber is impregnated, a kind of anchoring effect is produced on the carbon fiber. It is possible to cause the movement of the urinary resin to be moved.

[0037] In the carbon fiber structure used in the present invention, fine carbon fibers having such a predetermined outer diameter exist in a three-dimensional network, and these carbon fibers are composed of the carbon fibers. The granular portions formed during the fiber growth process are bonded to each other, and the granular portion has a shape in which a plurality of the carbon fibers extend. In this way, since the fine carbon fibers are not simply entangled with each other but are firmly bonded to each other in the granular portion, a strong structure is obtained when the skeleton structure is formed. be able to. Further, in the carbon fiber structure used in the present invention, since the carbon fibers are bonded to each other by the granular portion formed during the growth process of the carbon fiber, the structure is obtained. For example, the electrical resistance value measured at a constant compression density is a simple entanglement of fine carbon fibers, or the junction between fine carbon fibers. Compared with the value of a structure or the like that is later adhered by a carbonaceous substance or its carbide, the value is very low, and a good conductive path can be formed when a composite material is used.

[0038] Since the granular part is formed in the growth process of the carbon fiber as described above, the carbon-carbon bond in the granular part is sufficiently developed, and it is not clear exactly. Appears to contain a mixed state of sp ² and sp ³ bonds. After generation (intermediate and first intermediate described later), the granular part and the fiber part are continuous with a structure in which patch-like sheet pieces having carbon atomic force are bonded together, and thereafter After the high-temperature heat treatment, at least a part of the graphene layer constituting the granular portion is continuous with the graphene layer constituting the fine carbon fiber extending from the granular portion. In the carbon fiber structure used in the present invention, between the granular portion and the fine carbon fiber, it is a symbol that the graphene layer constituting the granular portion as described above is continuous with the darafen layer constituting the fine carbon fiber. Carbon crystal structural bonds (as at least (Some of them) are connected! /, Which forms a strong bond between the granular portion and the fine carbon fiber.

[0039] In this specification, the term "carbon fiber strength extends from the granular part" means that the granular part and the carbon fiber are merely apparently formed by other binders (including carbonaceous ones). It is not intended to indicate a state where they are connected with each other, but as described above, it is mainly connected with a carbon crystal structural bond.

[0040] Further, as described above, the granular part is formed in the growth process of the carbon fiber. As a trace, at least one catalyst particle or the catalyst particle is subjected to a subsequent heat treatment inside the granular part. In the process, there are vacancies generated by volatilization and removal. These pores (or catalyst particles) are essentially independent of the hollow portion formed inside each fine carbon fiber extending from the granular portion (note that only a small part is incidental) Some of them are connected to the hollow part;).

[0041] The number of catalyst particles or pores is not particularly limited, but there are about 1 to about LOOO, more preferably about 3 to 500 per granular part. By forming the granular portion in the presence of such a number of catalyst particles, it is possible to obtain a granular portion having a desired size as described later.

[0042] The size of each catalyst particle or hole existing in the granular part is, for example, 1 to: LOOnm, more preferably 2 to 40 nm, and still more preferably 3 to 15 nm. .

[0043] Further, although not particularly limited, it is desirable that the particle diameter of the granular portion is larger than the outer diameter of the fine carbon fiber as shown in FIG. Specifically, for example, the outer diameter of the fine carbon fiber is 1.3 to 250 times, more preferably 1.5 to: LOO times, and further preferably 2.0 to 25 times. In addition, the said value is an average value. In this way, if the particle size of the granular part, which is the bonding point between the carbon fibers, is sufficiently large as 1.3 times or more of the outer diameter of the fine carbon fiber, it is higher than the carbon fiber extending from the granular part When a skeleton structure is formed using this to form a composite material of the present invention and a composite material of the present invention is obtained, even if a certain amount of elasticity is applied, the three-dimensional network structure is maintained. Become. On the other hand, if the size of the granular portion is extremely large exceeding 250 times the outer diameter of the fine carbon fiber, the fibrous properties of the carbon fiber structure may be impaired, and the composite material according to the present invention. The skeletal structure that forms This is not desirable because there is a possibility that the structure is not suitable. As used herein, the “particle size of the granular part” is a value measured by regarding the granular part, which is a bonding point between carbon fibers, as one particle.

[0044] The specific particle size of the granular portion is a force that depends on the size of the carbon fiber structure and the outer diameter of the fine carbon fibers in the carbon fiber structure. For example, the average value is 20 to 5000 nm. It is preferably 25 to 2000 nm, more preferably about 30 to 500 nm.

[0045] Further, since the granular portion is formed in the carbon fiber growth process as described above, it has a relatively spherical shape, and its circularity is 0.2 on average. ~ <1, preferably ί or 0.5 to 0.99, more preferably ί or about 0.7 to 0.98.

[0046] As described above, the granular portion is formed in the carbon fiber growth process, and for example, the carbonaceous material is formed after the carbon fiber is synthesized at the junction between the fine carbon fibers. In addition, the bonding between the carbon fibers in the granular portion is very strong compared to a structure or the like attached by the carbide, and the carbon fiber breaks in the carbon fiber structure. Even below, this granular part (joint part) is kept stable. Specifically, for example, as shown in Examples described later, the carbon fiber structure is dispersed in a liquid medium, and an ultrasonic wave with a predetermined output and a predetermined frequency is applied to the carbon fiber structure, so that the average length of the carbon fibers is almost halved. Even under such a load condition, the change rate of the average particle diameter of the granular part is less than 10%, more preferably less than 5%, and the granular part, that is, the bonded part of the fibers is stably held. It is what has been.

[0047] The carbon fiber structure used in the present invention preferably has an area-based circle-equivalent mean diameter of about 50 to 500 m. Here, the area-based circle-equivalent mean diameter is obtained by photographing the outer shape of the carbon fiber structure using an electron microscope or the like, and in this photographed image, the contour of each carbon fiber structure is represented by appropriate image analysis software, for example, Using WinRoof (trade name, manufactured by Mitani Shoji Co., Ltd.), the area within the contour was obtained, the equivalent circle diameter of each fiber structure was calculated, and this was averaged. When the circle-equivalent average diameter is 50 m or less, the three-dimensional structure cannot sufficiently exhibit the effects such as conductivity and strength. The carbon fiber structure used for the skeletal structure is preferably larger, but if it is too large, it becomes difficult to handle as a powder, and therefore it is preferably 500 m or less. [0048] Further, as described above, in the carbon fiber structure used in the present invention, the carbon fibers existing in a three-dimensional network are bonded to each other in the granular portion, and the granular portion force is described above. In a single carbon fiber structure, if there are multiple granular parts that combine carbon fibers to form a three-dimensional network, there is a gap between adjacent granular parts. The average distance is, for example, 0.5 m to 300 m, more preferably 0.5 to: LOO / zm, more preferably about 1 to 50 / ζ πι. The distance between the adjacent granular parts is a distance measured from the central part of one granular body to the central part of the granular part adjacent thereto. If the average distance between the granular materials is less than 0.5 m, the carbon fiber does not fully develop into a three-dimensional network. On the other hand, if the average distance exceeds 300 m, the skeletal structure constituting the composite material becomes rough! / !, sufficient strength This is because there is a drowning that cannot be obtained.

[0049] In addition, the carbon fiber structure used in the present invention is such that carbon fibers existing in a three-dimensional network form are bonded to each other in the granular portion formed during the growth process! Therefore, as described above, the force that the electrical characteristics of the structure itself is very excellent, for example, the powder resistance value force measured at a constant compression density of 0.8 gZcm ³ is 0.02 Ω • cm or less. Desirably, it is preferably 0.001-0.010 Ω'cm. This is because when the powder resistance value exceeds 0.02 Ω'cm, it becomes difficult to form a good conductive path when a composite material is formed.

[0050] Next, a skeletal structure formed using the carbon fiber structure described above! I will explain in a moment.

The skeletal structure that forms the skeleton of the composite material of the present invention is configured by further three-dimensionally joining the above-described three-dimensional network-like carbon fiber structure with carbon. According to such a skeletal structure, compared to the conventional skeletal structure obtained by bonding carbon fibers alone, the carbon fiber that is the starting material itself has a three-dimensional network, so that it has a strong bond. It is a skeletal structure with high power and high conductivity.

[0051] The skeletal structure used in the present invention may contain boron. By containing boron, each carbon fiber can be made into a highly crystalline carbon fiber. You can. In the present invention, “boron is contained in the skeletal structure” means that boron is present on the surface of the skeletal structure in addition to a state in which a part of carbon atoms constituting the skeletal structure is substituted with boron. It also includes those that are attached.

[0052] The method for containing (doping) boron in the carbon fibers and the bonding carbon constituting the skeleton structure is not particularly limited, but for example, the carbon fiber and the bonding carbon may be heat-treated at a low temperature (eg, 1500 ° C or lower). The crystal is still developing! / Carbon fiber in the ヽ state, and after heat treatment! /, The carbon fiber in the グロ state is mixed with boron (including boron compounds), and then By annealing at a high temperature, boron can be contained in the carbon fiber and the bonded carbon. It is not impossible to incorporate boron into carbon fiber that has been treated with graphite at temperatures of 2000 ° C or higher, or even 2300 ° C or higher. Since boron also acts as a catalyst for accelerating crystallization of carbon fibers, it is preferable to contain boron before the graphite soot treatment.

[0053] The boron contained in the skeleton structure is not particularly limited. Here, “boron” in the present invention is a concept including not only elemental boron but also boron compounds. As described above, when boron is included in the skeletal structure, annealing is performed at a high temperature (for example, 1800 ° C or higher), so boron that has not evaporated by decomposition or the like before reaching at least 1800 ° C is used. It is necessary to use it. Examples of boron that satisfies this condition include elemental boron, B O, H BO, B C, and BN.

2 3 3 4 4

Can be mentioned.

[0054] The boron content is preferably 0.001 to 10 mass%, more preferably 0.01 to 3.0 mass%, based on the skeletal structure. If the boron content is less than 0.001% by mass, it is difficult to improve the effect of boron content, that is, the crystallinity of the carbon fiber. On the other hand, if the content exceeds 10% by mass, the heat treatment will not only increase the processing cost, but it may be easily melted and consolidated, or the fiber surface may be coated with boron, conversely deteriorating conductivity. There is a case to let you.

[0055] The size and shape of the skeleton structure constituting the composite material of the present invention are not particularly limited, and can be appropriately selected depending on the application field, required performance, and the like. However, for example, the bulk density is desirably 0.2 to 2.3 gZcm ³ , more preferably 0.4 to 2.1 cm ³ . If the bulk density exceeds 2.3 gZcm ³ , it will be difficult to impregnate the voids of the skeletal structure with resin or the like.

[0056] Further, the skeletal structure used in the present invention desirably has high strength and conductivity, and preferably has few defects in the graph sheet constituting the carbon fiber. Specifically, , For example, I measured by Raman spectroscopy,

D Λ ratio is

It is desirable that G is 0.25 or less, more preferably 0.1 or less, and I ZI is 0.6 to 1.5. here

G 'G

, Do, appear only 1580 cm ^_1 vicinity of the peak (G band) of graphite in the Raman spectroscopic analysis of up to 2000 cm ^_1, large single crystals. A peak (D band) appears in the vicinity of 1360 cm- ^{1 due} to the fact that the crystal is finite in size and lattice defects. In addition, when the measurement range is expanded, a G 'band appears near 27 OOcnT ¹ . For this reason, the intensity ratio of D band and G band (R = I

13

/ \ = 1 Zi) and G, the intensity ratio of band to G band (I / \ = I ZI)

60 1580 D G 2700 1580 G 'G As described above, it is recognized that the amount of defects in the graph sheet is small when it is within the predetermined range.

[0057] It should be noted that it is desirable to add boron to the graph ensheet when it is intended to obtain high conductivity even if it contains some defects in the structure. For example, the I measured by Raman spectroscopy is

D Λ ratio

G 0.2 to 1.4, and I G 'ZI is

G 0

It is desirable to be 2 to 0.8. The intensity ratio of this D band and G band (R = I / \ = 1

1360 1580

Zi) and G, and the intensity ratio of band to G band (I / \ = 1 Zi)

D G 2700 1580 G 'G

Within a certain range, the force is considered to contain boron in the graph ensheet. If boron is contained in the graph ensheet, the G-band waveform in Raman spectroscopy becomes asymmetric, and a shoulder appears on the high wavenumber side.

[0058] The skeletal structure used in the present invention desirably has a combustion start temperature in air of 700 ° C or higher, more preferably 800 to 900 ° C. As described above, since the carbon fiber structure constituting the skeleton structure has few defects and the carbon fiber has an intended outer diameter, it has such a high thermal stability. Become.

[0059] The carbon fiber structure having the desired shape as described above is not particularly limited, and can be prepared, for example, as follows. [0060] Basically, an organic compound such as a hydrocarbon is chemically pyrolyzed by a CVD method using a transition metal ultrafine particle as a catalyst to obtain a fiber structure (hereinafter referred to as an intermediate). When the metal fiber contains boron, after separating hydrocarbons such as this stage or tar, boron or a boron compound is mixed. Further, a high temperature heat treatment is performed. Note that boron or a boron compound may be mixed in advance with an organic compound such as a hydrocarbon (that is, boron is added before obtaining an intermediate), and further boron is mixed after a high-temperature heat treatment. It is also possible.

[0061] As the raw material organic compound, hydrocarbons such as benzene, toluene and xylene, alcohols such as carbon monoxide (CO) and ethanol can be used. Although not particularly limited, in obtaining the fiber structure used in the present invention, it is preferable to use at least two or more carbon compounds having different decomposition temperatures as the carbon source. As used herein, “at least two or more carbon compounds” does not necessarily mean that two or more kinds of raw material organic compounds are used, but a case where one kind of raw material organic compound is used. Even in the process of synthesizing the fiber structure, for example, a reaction such as hydrodealkylation of toluene-xylene occurs, and the subsequent pyrolysis reaction system! It also includes a mode in which two or more carbon compounds having different!

[0062] When two or more kinds of carbon compounds are present as carbon sources in the thermal decomposition reaction system, the decomposition temperature of each carbon compound is not limited to the type of carbon compound. Therefore, by adjusting the composition ratio of two or more carbon compounds in the raw material gas, a relatively large number of combinations are used as the carbon compounds. be able to.

[0063] For example, alkanes or cycloalkanes such as methane, ethane, propanes, butanes, pentanes, hexanes, heptanes, cyclopropane, cyclohexane, etc., particularly alkanes having about 1 to 7 carbon atoms; ethylene, Alkenes such as propylene, butylenes, pentenes, heptenes, cyclopentene, etc., especially alkenes having about 1 to 7 carbon atoms; alkynes such as acetylene and propyne, especially alkynes having about 1 to 7 carbon atoms; benzene, tolylene , Styrene, xylene, naphthalene, methenolenaphthalene, indene, Aromatic or heteroaromatic hydrocarbons such as phenanthrene, especially aromatic or heteroaromatic hydrocarbons having about 6 to 18 carbon atoms, alcohols such as methanol and ethanol, especially alcohols having about 1 to 7 carbon atoms; In addition, the gas partial pressure should be adjusted so that two or more types of carbon compounds, such as carbon monoxide, ketones, ethers, etc., selected in the middle, can be used in the desired thermal decomposition reaction temperature range to exhibit different decomposition temperatures. It is possible to adjust and use in combination, and to adjust the residence time in a predetermined temperature range or Z, and by optimizing the mixing ratio, the carbon fiber structure used in the present invention can be efficiently used. Can be manufactured

[0064] Among such combinations of two or more carbon compounds, for example, in the combination of methane and benzene, the molar ratio of methane / benzene is> 1 to 600, more preferably 1.1 to 200, More preferably, 3 to: LOO is desirable. This value is the gas composition ratio at the inlet of the reactor. For example, when toluene is used as one of the carbon sources, toluene is decomposed 100% in the reactor and methane and benzene are 1 : In consideration of what occurs in 1, it is sufficient to supply the shortage of methane separately. For example, if the molar ratio of methane to benzene is 3, add 2 moles of methane to 1 mole of toluene. Note that methane to be added to toluene is not limited to the method of preparing fresh methane separately, but unreacted methane contained in the exhaust gas discharged from the reactor is circulated and used. It is also possible to use it.

[0065] By setting the composition ratio within such a range, it is possible to obtain a carbon fiber structure having a structure in which both the carbon fiber portion and the granular portion are sufficiently developed.

[0066] As the atmospheric gas, an inert gas such as argon, helium, xenon, or hydrogen can be used.

[0067] Further, as the catalyst, a mixture of transition metals such as iron, cobalt and molybdenum, transition metal compounds such as iron cene, and metal acetates, and sulfur compounds such as sulfur, thiophene and iron sulfide is used.

[0068] The synthesis of the intermediate is performed by using a CVD method such as hydrocarbon, which is usually performed, and evaporating the mixed liquid of hydrocarbon and catalyst as raw materials and introducing hydrogen gas or the like into the reactor as a carrier gas. And pyrolyze at a temperature of 800-1300 ° C. As a result, the outer diameter is 15 ~: An assembly of several centimeters of force and several tens of centimeters in which a plurality of carbon fiber structures (intermediates) having a sparse three-dimensional structure joined together by granular materials grown using the catalyst particles as cores. Synthesize.

[0069] The pyrolysis reaction of the hydrocarbon as a raw material is mainly produced on the surface of granular particles that are grown using the catalyst particles as a nucleus, and the recrystallization of carbon generated by the decomposition is caused by the catalyst particles or granular materials. By proceeding in a certain direction, it grows in a fibrous form. However, in order to obtain the carbon fiber structure according to the present invention, the tolerance between the thermal decomposition rate and the growth rate is intentionally changed, for example, as described above, the decomposition temperature as a carbon source. By using at least two or more different carbon compounds, the carbon material is grown three-dimensionally around the granular material that does not grow the carbon material only in one-dimensional direction. Of course, the growth of such three-dimensional carbon fibers is not dependent only on the balance between the pyrolysis rate and the growth rate, but the crystal face selectivity of the catalyst particles, the residence time in the reactor, The temperature distribution is also affected, and the balance between the pyrolysis reaction and the growth rate is affected not only by the type of carbon source as described above but also by the reaction temperature and gas temperature. In general, when the growth rate is faster than the pyrolysis rate as described above, the carbon material grows in a fibrous form, whereas when the pyrolysis rate is faster than the growth rate, the carbon material becomes a catalyst particle. Grows in the circumferential direction. Therefore, by intentionally changing the balance between the thermal decomposition rate and the growth rate, the growth direction of the carbon material as described above is made to be a multi-direction under control without making the growth direction constant. Such a three-dimensional structure can be formed. In order to easily form a three-dimensional structure as described above in which the fibers are bonded together by granular materials in the produced intermediate, the composition of the catalyst, the residence time in the reaction furnace, the reaction temperature, and the gas It is desirable to optimize the temperature and the like.

[0070] In addition, as a method for efficiently producing the carbon fiber structure used in the present invention, a reaction other than the above-described approach using two or more carbon compounds having different decomposition temperatures at an optimum mixing ratio may be used. One approach is to generate turbulence in the vicinity of the supply port of the raw material gas supplied to the furnace. The turbulent flow here is a turbulent and turbulent flow.

[0071] In the reaction furnace, immediately after the source gas is introduced into the reaction furnace from the supply port. In addition, the metal catalyst fine particles are formed by the decomposition of the transition metal compound as the catalyst in the raw material mixed gas, and this is brought about through the following steps. That is, the transition metal compound is first decomposed into metal atoms, and then, cluster formation occurs by collision of a plurality of, for example, about 100 atoms. At the stage of this generated cluster, it does not act as a catalyst for fine carbon fibers, and the generated clusters further gather together by collision, resulting in about 3ηπ! It grows to crystalline particles of about lOnm and is used as metal catalyst fine particles for the production of fine carbon fibers.

[0072] In this catalyst formation process, if there is a vortex due to intense and turbulent flow as described above, more intense collisions are possible compared to collisions between metal atoms or clusters with only Brownian motion, By increasing the number of collisions per unit time, metal catalyst fine particles can be obtained in a high yield in a short time, and by concentrating the concentration, temperature, etc. by eddy current, metal catalyst fine particles with uniform particle size can be obtained. be able to. Furthermore, in the process of forming the metal catalyst fine particles, an aggregate of metal catalyst fine particles in which a large number of metal crystalline particles are gathered is formed by vigorous collision due to the vortex. Since the metal catalyst fine particles are generated promptly in this way, the decomposition of the carbon compound is promoted and sufficient carbon material is supplied, and each metal catalyst fine particle of the aggregate is radially formed as a nucleus. On the other hand, if the thermal decomposition rate of some of the carbon compounds is faster than the growth rate of the carbon material as described above, the carbon material also grows in the circumferential direction of the catalyst particles, A granular portion is formed around the aggregate to efficiently form a carbon fiber structure having an intended three-dimensional structure. The aggregate of metal catalyst fine particles may include catalyst fine particles that are less active than other catalyst fine particles or that have been deactivated during the reaction. The non-fibrous or very short fibrous shape that has grown on the surface of such a catalyst fine particle before agglomerating as an aggregate, or has grown with such a catalyst fine particle as a nucleus after becoming an aggregate. This carbon material layer is considered to form the granular part of the carbon fiber structure according to the present invention by being present at the peripheral position of the aggregate.

[0073] Specific means for generating a turbulent flow in the raw material gas flow in the vicinity of the raw material gas supply port of the reaction furnace is not particularly limited. For example, a collision part is provided at a position where it can interfere with the flow of the raw material gas Measures can be taken. The shape of the collision part is not limited in any way as long as a sufficient turbulent flow is formed in the reactor by the vortex generated from the collision part. For example, various shapes of baffle plates If one or more paddles, taper tubes, umbrellas, etc. are used alone or in combination, a plurality of forms can be adopted.

[0074] In this way, the intermediate obtained by heating the catalyst and hydrocarbon mixed gas at a constant temperature in the range of 800 to 1300 ° C is pasted with patch-like sheet pieces that also contain carbon nuclear power. It has a combined (incomplete, burnt-in) structure, and when it is analyzed by Raman spectroscopy, there are many defects that are very large. In addition, since the generated intermediate contains unreacted raw materials, non-fibrous carbides, tar content and catalytic metal, it was heated at 800-1200 ° C to remove volatile content such as unreacted raw materials and tar content. You can use it later for the skeletal structure! In addition, high-temperature heat treatment (1800 ° C or higher) may be applied to the intermediate and then used for the skeleton structure. However, as described above, it is preferable that the surface energy of boron doping is also good! /.

[0075] It should be noted that before or after such high-temperature heat treatment, the carbon fiber structure has a circle equivalent average diameter of 50 to 500 m, and is subjected to a step of crushing and pulverizing to obtain a desired circle equivalent average diameter. A carbon fiber structure is obtained.

[0076] The method for producing a skeleton structure according to the present invention having such characteristics is not particularly limited, but specific examples are as follows.

[0077] First, the carbon fiber structure described above and the organic noinder are mixed and kneaded by using a double-arm / single-mixer type kneader. Examples of the noda include thermosetting resin or pitch. Thermosetting resin is in a liquid state at room temperature, or in a solid state but becomes a liquid state at a heating temperature of about 50 to 90 ° C. It is crosslinked by a curing process by heating at about 100 to 200 ° C. It has the property of polymerizing into a polymer and solidifying. If it is decomposed and carbonized without heating even when heated to a high temperature!ヽぅ Have properties! / Anything that can be used is acceptable. There are various types of pitch, but any pitch such as isotropic pitch and mesophase pitch may be used.

[0078] In the thermosetting resin using a solvent during kneading, the solvent is dried at a temperature that does not cure the thermosetting resin after kneading. [0079] Subsequently, when the carbon fiber structure is mixed and kneaded with the thermosetting resin to form a lump, the carbon fiber structure is crushed and used for the next forming step.

[0080] In the molding step, a method in which vertical force pressing is performed using a mold, a method in which isotropic pressing is performed with a hydrostatic pressure using a rubber mold, and the like are preferable.

[0081] The molding pressure during pressing is preferably about 1 to 2000 kg / cm ³ . The carbon fiber structures are bonded with thermosetting resin during molding, but if the pressure is weakened if the thermosetting resin is not cured, the carbon fiber structure will be restored. Since the bonded material is removed due to the property, it is preferable to heat the thermosetting resin by heating to a temperature of about 100 to 200 ° C. during pressing to increase the bonding force.

[0082] Next, the thermosetting resin is carbonized by heating the molded product obtained by curing the thermosetting resin in a deoxygenated atmosphere or an inert gas atmosphere. The thermosetting resin is decomposed and carbonized within a range of 300 to 900 ° C, and further subjected to an annealing treatment at a high temperature, whereby the patch-like sheet pieces constituting the carbon fiber structure are bonded to each other. A plurality of dalafen sheet-like layers are formed. In the annealing process, the carbonized portion of the thermosetting resin is also modified and graphitized in the same manner as the carbon fiber structure.

[0083] When pitch is used for the noinder, it is infusibilized in an oxidizing atmosphere at 150 to 400 ° C after press molding, and then carbonized at 800 to 1500 ° C.

[0084] In the stage of performing the high-temperature heat treatment, boron can be contained (doped) in the crystal of the carbon fiber by mixing the compact and boron. Here, in order to efficiently contain boron in the crystal of the carbon fiber structure, it is necessary to mix the carbon fiber structure and boron well so that they are in uniform contact. . For this purpose, it is preferable to use boron (or boron compound) particles having a particle size as small as possible. If the particles are large, a high-concentration region is partially generated, which may cause consolidation. Specifically, the average particle size of boron is 100 m or less, preferably 50 m or less, more preferably 20 m or less. In addition, when boric acid or the like is used as the boron source, a method of adding it as an aqueous solution and evaporating water in advance or a method of evaporating water in a caloric heat process can be used. If the aqueous solution is uniformly mixed, the boron compound can be uniformly adhered to the fiber surface after the water evaporation. [0085] Even if a deviation of the thermosetting resin or pitch is used, pressure is applied to the molded body until the binder is cured or infusible to prevent contact and separation of the joint portion due to restoration of the carbon fiber structure. It is preferable. More preferably, it is preferable to keep the pressure under pressure when the binder in the carbonization and graphite process is carbonized and the carbon fiber structure and carbon derived from the binder are graphitized. When heat treatment is performed at a high temperature of 1800 ° C or higher, the carbon fiber structure is heat-treated while being restrained, and the shape of the carbon fiber structure in the molded body can be fixed by annealing.

[0086] Next, after the above carbonization and graphitization steps, a resin, rubber, metal, carbon-based resin is formed in a void formed inside a skeleton structure in which a carbon fiber structure is bonded with carbon. An impregnation process for impregnating the material is performed.

[0087] Examples of the resin to be impregnated in the impregnation step include polypropylene, polyethylene, polystyrene, polychlorinated butyl, polyacetal, polyethylene terephthalate, polycarbonate, polybutyrate, polyamide, polyamideimide, polyetherimide, polyetheretherketone. , Polyvinyl alcohol, polyphenylene ether, poly (meth) acrylate, liquid crystal polymer and other thermoplastic resins, epoxy resins, burester resin, phenol resin, unsaturated polyester resin, furan resin, imide resin Examples thereof include various thermosetting resins such as fats, urethane resins, melamine resins, silicone resins and urea resins. Natural rubber, styrene butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), ethylene propylene rubber (EPD M), nitrile rubber (NBR), chloroprene rubber (CR ), Butyl rubber (IIR), urethane rubber, silicone rubber, fluorine rubber, acrylic rubber (ACM), epichlorohydrin rubber, ethylene acrylic rubber, norbornene rubber and the like. Examples of the metal to be impregnated include aluminum, magnesium, lead, copper, tungsten, titanium, niobium, hafnium, vanadium, and alloys and mixtures thereof. Further, as an impregnating force, the one-bon-based material includes, for example, glassy carbon.

[0088] As the impregnation method, either a pressure method or a suction method can be applied. When a pressure type impregnation apparatus is used, the aforementioned skeletal structure and impregnation material are inserted into a compression mold composed of a female mold and a male mold, and the impregnation material is placed inside the skeleton structure by pressure. Formed Impregnated into the voids. The compression mold can be heated by a heater. When the impregnating material is a resin monomer that is cured by a curing agent, heating by the heater is not necessary. This pressure method is applicable to all of the above impregnated materials

On the other hand, in the case of using a suction type impregnation apparatus, it is not applicable when the impregnation material is a metal or a carbon-based material, but it is an effective method for a resin monomer cured by a curing agent.

[0090] The volume% of the skeletal structure with respect to the entire composite material of the present invention depends on the porosity of the skeletal structure and the type of impregnating material, and cannot be generally specified. 99.9% is preferred 30 to 90% is particularly preferred. When the volume% of the skeletal structure is 10% or less, the strength of the skeletal structure is not sufficient. On the other hand, if the volume% of the skeletal structure is 99.9% or more, it is difficult to impregnate the material into the voids.

[0091] Further, regarding the composite material according to the present invention, when specific examples are shown according to the function of the carbon fiber structure to be blended, the following are exemplified, but of course, the present invention is not limited to these. Is not something

[0092] 1) Using electrical conductivity

As a conductive resin and a conductive resin molding by impregnating the resin, it is suitably used for packaging materials, gaskets, containers, resistors, electric wires, and the like. The same effect can be expected for composite materials impregnated with inorganic materials, especially ceramics, metals, etc., in addition to composite materials with resin.

[0093] 2) Using thermal conductivity

It can be used in the same manner as in the case of using the conductivity.

[0094] 3) Using electromagnetic wave shielding

It is suitable as an electromagnetic shielding material or the like by impregnating with rosin.

[0095] 4) Using physical properties

By impregnating with grease or metal to improve slidability, it can be used for rolls, brake parts, tires, bearings, lubricants, gears, pantographs, and the like. In addition, it will be possible to use it for the body of electric wires, home appliances 'vehicles' airplanes, etc., and the housing of machinery by utilizing its light weight and tough characteristics. In addition, it can also be used as a substitute for conventional carbon fibers and beads, and can be applied to battery pole materials, switches, and vibration-proof materials, for example.

[0096] 5) Using filler properties

The fine fibers of the carbon fiber structure have excellent strength, flexibility, and excellent filler characteristics that constitute a network structure. By utilizing this characteristic, it can contribute to the enhancement of the electrodes of the energy devices such as lithium-ion secondary battery, lead-acid battery, capacitor, fuel cell and the improvement of cycle characteristics.

Example

Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the following examples.

In the following, each physical property value of the carbon fiber structure used in the present invention was measured as follows.

[0098] <Area-based circle-equivalent mean diameter>

First, take a photograph of the pulverized product with SEM. In the obtained SEM photograph, only the carbon fiber structure with a clear outline was the target, and the carbon fiber structure that was broken was unclear because the outline was unclear. All carbon fiber structures (about 60 to 80) that can be targeted in one field of view were used, and about 200 carbon fiber structures were targeted in three fields of view. The contour of each carbon fiber structure is traced using image analysis software WinRoof (trade name, manufactured by Mitani Corporation), the area within the contour is obtained, and the equivalent circle diameter of each fiber structure is calculated. This was averaged.

[0099] <Measurement of bulk density>

Fill a transparent cylinder with an inner diameter of 70 mm with lg powder, pressure 0. IMpa, capacity 1.3 liters of air. Measure the height of the powder layer after settling at the time of blowing out 5 times. At this time, the number of measurement locations was assumed to be 6, and the average of the 6 locations was obtained, and then the bulk density was calculated.

[0100] <Raman spectroscopy>

Using LabRam800 manufactured by Horiba Jobin Yvon, the wavelength of 514nm of the argon laser And measured.

[0101] <Conductivity>

The conductivity of the obtained plate-shaped test piece was measured using a four-point probe low resistivity meter (Made by Mitsubishi Kagaku Co., Ltd., Loresta GP), and the volume resistance (Ω'cm) was measured using the same resistance meter. Converted and calculated the average value

[0102] <TG combustion temperature>

Using Mac Science TG-DTA, the temperature was increased at a rate of 10 ° CZ while flowing air at a flow rate of 0.1 liters Z, and the combustion behavior was measured. During combustion, TG shows a weight loss and DTA shows an exothermic peak, so the top position of the exothermic peak was defined as the combustion start temperature.

[0103] <Restorability>

CNT powder lg is weighed, filled and compressed into a resin die (inner dimensions L 40mm, W 10mm, H 80mm), and the displacement and load are read. When the density of 0.9 gZcm ³ was measured, the pressure was released and the density after restoration was measured.

[0104] <Average particle diameter of granular part, circularity, ratio with fine carbon fiber>

As with the measurement of the circle-based average diameter based on area, first take a picture of the carbon fiber structure with SEM. In the obtained SEM photographs, only the carbon fiber structure with a clear outline was targeted, and those with a collapsed carbon fiber structure were not targeted because the outline was unclear. All carbon fiber structures (about 60 to 80) that can be targeted in one field of view were used, and about 200 carbon fiber structures were targeted in three fields of view.

[0105] For each target carbon fiber structure, the granular part, which is the bonding point between carbon fibers, is regarded as one particle, and its outline is image analysis software WinRoof (trade name, Mitani Corp. The area within the contour was obtained, and the equivalent circle diameter of each granular part was calculated and averaged to obtain the average particle diameter of the granular part. Also, the circularity (R) is calculated based on the following equation from the area (A) in the contour measured using the image analysis software and the measured contour length (L) of each granular portion. The degree was obtained and averaged.

[0106] [Equation 1]

R = A water 4 TU / L ² [0107] Further, the outer diameter of the fine carbon fiber in each target carbon fiber structure is obtained, and from this and the equivalent circle diameter of the granular part of each carbon fiber structure, the granular part in each carbon fiber structure Was determined as a ratio to the fine carbon fiber and averaged.

[0108] <Average distance between granular parts>

[0109] In each of the targeted carbon fiber structures, all the portions where the granular portions are connected by the fine carbon fibers are searched, and the distance between the adjacent granular portions connected by the fine carbon fibers in this way (granularity at one end) Body center force The length of the fine carbon fiber including the center of the granular material at the other end) was measured and averaged.

[0110] <Destructive test of carbon fiber structure>

A carbon fiber structure was added to 100 ml of toluene placed in a vial with a lid at a rate of 30 gZml to prepare a dispersion sample of the carbon fiber structure.

[0111] With respect to the carbon fiber structure dispersion liquid sample thus obtained, using an ultrasonic cleaner with a transmission frequency of 38 kHz and an output of 150 w (trade name: USK-3, manufactured by SNEUDY Co., Ltd.) Ultrasonic waves were irradiated, and changes in the carbon fiber structure in the dispersion sample were observed over time.

[0112] First, an ultrasonic wave is irradiated, and after 30 minutes, a predetermined amount of 2 ml of the dispersion liquid sample is withdrawn from the bottle, and a photograph of the carbon fiber structure in the dispersion liquid is taken with an SEM. 200 fine carbon fibers (fine carbon fibers with at least one end bonded to the granular part) in the carbon fiber structure of the obtained SEM photograph were randomly selected, and each selected fine carbon fiber was selected. The length was measured to determine the D average value, which was used as the initial average fiber length.

50

[0113] On the other hand, 200 granular parts that are the bonding points between carbon fibers in the carbon fiber structure of the obtained SEM photograph were randomly selected, and each selected granular part was regarded as one particle. The contour is traced using image analysis software WinRoof (trade name, manufactured by Mitani Trading Co., Ltd.), the area within the contour is obtained, and the equivalent circle diameter of each granular part is calculated. The average value was obtained. The obtained D average value was used as the initial average diameter of the granular portion.

0 50

[0114] Thereafter, a fixed amount 2 ml of the dispersion liquid sample was taken out from the bottle at regular time intervals in the same manner as described above, and a photograph of the carbon fiber structure in the dispersion liquid was taken with an SEM. SEM photo D Fine length of carbon fiber in carbon fiber structure and D of granular part

The 50 50 average diameter was determined in the same manner as described above.

[0115] Then, the calculated D average length of fine carbon fibers is about half of the initial average fiber length.

50

The D average diameter of the granular portion at the time (in this example was irradiated with ultrasonic waves and after 500 minutes had elapsed) was compared with the initial average diameter, and the fluctuation ratio (%) was examined.

50

[0116] (Example 1)

i) Synthesis of carbon fiber structure

A carbon fiber structure was synthesized using toluene as a raw material by the CVD method.

[0117] The catalyst was a mixture of phlocene and thiophene, and the reaction was performed in a reducing atmosphere of hydrogen gas. Toluene and catalyst were heated together with hydrogen gas to 380 ° C, supplied to the production furnace, and pyrolyzed at 1250 ° C to obtain a carbon fiber structure (first intermediate).

[0118] FIGS. 1 and 2 show SEM and TEM photographs of the first intermediate dispersed in toluene and observed after preparing a sample for an electron microscope.

[0119] Fig. 4 shows a schematic configuration of the generating furnace used in producing this carbon fiber structure (first intermediate). As shown in FIG. 4, the generating furnace 1 has a power having an introduction nozzle 2 for introducing a raw material mixed gas composed of toluene, a catalyst and hydrogen gas as described above into the generating furnace 1 at its upper end. Further, a cylindrical collision portion 3 is provided outside the introduction nozzle 2. The collision part 3 can interfere with the flow of the raw material gas introduced into the reactor through the raw material gas supply port 4 located at the lower end of the introduction nozzle 2. In the production furnace 1 used in this example, the inner diameter a of the introduction nozzle 2, the inner diameter b of the production furnace 1, the inner diameter c of the cylindrical collision part 3, and the raw material mixed gas from the upper end of the production furnace 1 Each dimension is defined as follows: distance d to inlet 4; distance e from raw material mixed gas inlet 4 to the lower end of collision section 3; and f from raw material mixed gas inlet 4 to the lower end of generation furnace 1. The ratio was approximately a: b: c: d: e: f = l. 0: 3.6: 1.8: 3.2: 2.0: 21.0. The feed gas introduction rate into the reactor was 1850 NLZmin and the pressure was 1.03 atm. [0120] The intermediate synthesized as described above was calcined in nitrogen at 900 ° C to separate hydrocarbons such as tar to obtain a second intermediate. The R value of this second intermediate measured by Raman spectroscopy was 0.82.

[0121] Fig. 3 shows the SEM photograph of the obtained carbon fiber structure as it is placed on the electron microscope sample holder, and Table 1 shows the particle size distribution.

[0122] Further, the obtained carbon fiber structure had a circle-equivalent mean diameter of 155 m, a bulk density of 0.000029 g / cm ³ , a Raman I / \ ratio value of 0.82, and a density after restoration of 0. 25 g / cm ³ .

D G

[0123] Further, the average particle size of the granular portion in the carbon fiber structure was 443 nm (SD207 nm), which was 7.38 times the outer diameter of the fine carbon fiber in the carbon fiber structure. The circularity of the granular part was 0.67 (SD 0.14) on average.

[0124] Further, when the carbon fiber structure was subjected to a destructive test according to the procedure described above, the initial average fiber length (D) after 30 minutes of ultrasonic application was 12.8 m. 500 minutes later

50

The average fiber length (D) of 6.7 m is almost half of 6.7 m.

50

It was shown that many cuts occurred in the fine carbon fibers. The average diameter (D) of the granular part 500 minutes after ultrasonic application was compared with the initial average diameter (D) 30 minutes after ultrasonic application.

However, the fluctuation (decrease) rate is only 4.8%, and considering the measurement error etc., the cut granular part itself is almost destroyed even under the load condition where many cuts are generated in the fine carbon fiber. It became clear that it functions as a bonding point between fibers.

[0125] Table 2 summarizes various physical property values of the carbon fiber structure synthesized in Example 1.

[0126] [Table 1]

[0127] [Table 2] Example 1

Circle equivalent average diameter 1 55 / i m

^ Density 0.0029 g / cm ³

I n / I G ratio 0.82

Density after restoration 0.25 g / cm ³

[0128] ii) Formation of skeletal structure

A skeleton structure was formed using the carbon fiber structure synthesized in i) above.

Specifically, phenolic resin (Gunei Chemical Industry Co., Ltd., Resid Top) using methanol as a solvent was added to and mixed with the carbon fiber structure synthesized in i). The binder was added in an amount of 25% by mass with respect to the carbon fiber structure. Next, the obtained kneaded material was dried on a hot plate at 70 ° C., dried, and then heat-molded at 150 ° C. to cure the phenolic resin. Next, the obtained molded body was heated to 2500 ° C. in an argon gas atmosphere to obtain a skeleton structure in which the binder component was carbonized and graphitized.

[0129] Table 3 shows the physical property values of the skeleton structure of Example 1.

[0130] (Example 2)

A solution in which B 2 O is dissolved in methanol in a molded body obtained by curing rosin as in Example 1.

twenty three

The step of impregnating and drying was repeated so that the amount of boron added was 3.5% by mass relative to the compact. The formed body supporting boron was heated to 2500 ° C. in an argon gas atmosphere in the same manner as in Example 1 to obtain a skeleton structure in which the binder component was carbonized and graphitized.

[0131] Table 3 shows the physical property values of the skeleton structure of Example 2.

[0132] [Table 3] Example 1 Example 2

Bulk density (gZcm ³ ) 0. 71 0. 71

Raman I _π / 1 G ratio 0.22 0. 67

Raman I _G 'ZI (; ratio 0. 70 0. 23

Compressive strength (kN)> 10> 1 0

Volume resistance (Ω cm) 0. 010 0. 004

TG combustion temperature (° C) 707 720

Claims

The scope of the claims

[1] Outer diameter 15 ~: It has a three-dimensional network configuration that also includes the LOOnm carbon fiber force, and has a granular part that binds the carbon fibers to each other in a form in which a plurality of the carbon fibers extend. The skeletal structure is characterized in that the granular part is formed by joining a carbon fiber structure formed in the carbon fiber growth process in three dimensions with carbon.

[2] Contains boron! 2. The skeletal structure according to claim 1, wherein the skeleton structure is wound.

[3] The skeletal structure according to claim 2, wherein a content of the boron is 0.001 to 10% by mass with respect to the skeleton structure.

[4] The skeleton structure according to any one of claims 1 to 3, wherein the carbon fiber structure has an area-based circle-equivalent mean diameter of 50 to 500 m.

[5] The skeletal structure is measured by Raman spectroscopy.

D Λ G is the following, and I / \ is 1.5 or less, according to any one of claims 1 to 4,

G 'G

Skeletal structure.

[6] The skeleton structure has a bulk density of 0.2 to ^2.3 g / cm3.

The skeletal structure according to any one of 1 to 5.

7. The skeletal structure according to any one of claims 1 to 6, wherein the skeletal structure has a combustion start temperature in air of 700 ° C or higher.

[8] The bonding portion of the carbon fiber according to any one of claims 1 to 7, wherein a particle size of the granular portion is larger than an outer diameter of the carbon fiber. Skeletal structure.

[9] The skeleton according to any one of claims 1 to 8, wherein the carbon fiber structure is produced using at least two or more carbon compounds having different decomposition temperatures as a carbon source. Structure.

[10] Outer diameter 15 ~: It exhibits a three-dimensional network configuration that also includes the LOOnm carbon fiber force, and has a granular portion that binds the carbon fibers to each other in a manner in which a plurality of the carbon fibers extend. And the granular part has a skeletal structure formed by joining a carbon fiber structure formed in the carbon fiber growth process in three dimensions with carbon, A composite material characterized in that voids formed inside the skeleton structure are impregnated with resin, rubber, metal, or carbon-based material.

[11] The composite material according to [10], wherein the skeleton structure contains boron.

12. The composite material according to claim 11, wherein a content of the boron is 0.001 to 10% by mass with respect to the skeleton structure.

[13] The composite material according to any one of [10] to [12], wherein the carbon fiber structure has an area-based circle-equivalent mean diameter of 50 to 500 m.

[14] The skeletal structure is measured by Raman spectroscopy.

D Λ is 1.4 or less, and G

The I / \ is not more than 1.5, according to any one of claims 10 to 13,

G 'G

Composite material.

[15] the framework structure, the claims bulk density, characterized in that it is a 0. 2~2. 3gZcm ³

The composite material according to any one of 10 to 14.

16. The composite material according to any one of claims 10 to 15, wherein the skeletal structure has a combustion start temperature in air of 700 ° C or higher.

[17] The method according to any one of [10] to [16], wherein a particle diameter of the granular portion is larger than an outer diameter of the carbon fiber at a bonding portion of the carbon fibers. Composite material.

[18] The composite according to any one of [10] to [17], wherein the carbon fiber structure is formed using at least two or more carbon compounds having different decomposition temperatures as a carbon source. material.