JP2023038471A - Method and apparatus for producing carbon composite - Google Patents

Abstract

Kind Code: A1 A method for producing a carbon composite is provided in which carbon spherical particles and carbon rod-shaped particles are uniformly dispersed and a carbon composite having excellent electrical conductivity can be produced. A production method for producing a carbon composite containing carbon spherical particles and carbon rod-shaped particles comprises reacting a mixed gas containing a first carbon source and a precursor of a rod-shaped catalyst, a first step of obtaining a reaction product containing carbon spherical particles; A method for producing a carbon composite, comprising a second step of obtaining a carbon composite containing [Selection drawing] Fig. 2

Description

Application for application of Article 30, Paragraph 2 of the Patent Act is filed Date of issue: September 10, 2020 Publication: Abstracts of the 51st Autumn Meeting of the Society of Chemical Engineers, Japan (online publication) [Publications, etc.] Date: September, 2020 26th Meeting Name, Venue The 51st SCEJ Autumn Meeting (held online)

The present invention relates to a method for producing a carbon composite containing carbon spherical particles and carbon rod-shaped particles, and a production apparatus for producing the carbon composite.

BACKGROUND ART Conventionally, carbon black is contained in rubber, resin or the like to impart electrical conductivity.

In recent years, there has been a demand for a conductive agent capable of imparting high conductivity without deteriorating the inherent properties of resins and the like, and the use of carbon nanotubes as a conductive agent has been investigated. However, carbon nanotubes have problems such as poor dispersibility and high cost.

In order to solve these problems, for example, Patent Document 1 discloses a method for manufacturing a composite in which fibrous carbon and spherical carbon particles are combined.

JP 2010-77313 A

However, the production method described in Patent Document 1 has a problem that it is difficult to uniformly disperse fibrous carbon in the reaction field for forming spherical carbon particles, making it difficult to produce a uniform composite.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method for producing a carbon composite, in which carbon spherical particles and carbon rod-shaped particles are uniformly dispersed and a carbon composite having excellent electrical conductivity can be produced. Another object of the present invention is to provide a manufacturing apparatus capable of manufacturing the carbon composite.

One aspect of the present invention is a production method for producing a carbon composite containing carbon spherical particles and carbon rod-shaped particles, wherein a mixed gas containing a first carbon source and a rod-shaped catalyst precursor is reacted. a first step of obtaining a reaction product containing carbon spherical particles; and a second carbon source is added to the reaction product produced in the first step to react with the carbon spherical particles. and a second step of obtaining a carbon composite containing carbon rod-shaped particles.

In one embodiment, the first step may be a step of obtaining a reaction product containing carbon spherical particles and decomposition products of the precursor from the mixed gas.

In one aspect, the first step may be a step of reacting the gas mixture at a temperature _T1 , and the second step is a step of reacting the mixture of the reaction product and the second carbon source at the temperature T. It may be a step of reacting at a temperature _T2 of less than ₁ .

In one aspect, the difference between T ₁ and T ₂ (T ₁ −T ₂ ) may be 100° C. or more.

The production method according to one aspect further includes a mixing step of obtaining the mixed gas by mixing the first gas containing the first carbon source and the second gas containing the precursor. good.

In one aspect, the precursor may contain iron atoms.

In one aspect, the precursor may include ferrocene.

In one aspect, the mixed gas may further contain at least one sulfur component selected from the group consisting of elemental sulfur and sulfur-containing compounds containing sulfur atoms.

In one aspect, the first carbon source may comprise acetylene.

Another aspect of the present invention is a production apparatus for producing a carbon composite containing carbon spherical particles and carbon rod-shaped particles, comprising a first reaction section, a first carbon source and a rod-shaped catalyst A first supply path for supplying a mixed gas containing a precursor of and to the first reaction part, a second reaction part, and a reaction product obtained in the first reaction part, It relates to a production apparatus comprising a second supply channel for supplying two reaction parts, and a third supply channel for supplying a second carbon source to the second reaction part.

According to the present invention, there is provided a method for producing a carbon composite, in which carbon spherical particles and carbon rod-shaped particles are uniformly dispersed and a carbon composite having excellent conductivity can be produced. Further, according to the present invention, there is provided a manufacturing apparatus capable of manufacturing the carbon composite.

FIG. 1 is a schematic cross-sectional view showing one mode of a carbon composite manufacturing apparatus. 2 is a diagram showing an example of an SEM observation image of the carbon composite of Example 1. FIG. 3 is a diagram showing an example of an SEM observation image of the black powder of Comparative Example 1. FIG. 4(a) and 4(b) are diagrams showing examples of SEM observation images of the composite of Comparative Example 2. FIG.

Preferred embodiments of the present invention are described in detail below.

The production method of the present embodiment is a method for producing a carbon composite containing carbon spherical particles and carbon rod-shaped particles. The production method of the present embodiment includes a first step of reacting a mixed gas containing a first carbon source and a rod-shaped catalyst precursor to obtain a reaction product containing carbon spherical particles; and a second step of adding a second carbon source to the reaction product produced in the step of (1) and reacting it to obtain a carbon composite containing carbon spherical particles and carbon rod-like particles.

In the first step of this embodiment, carbon spherical particles are produced by thermal decomposition of the first carbon source. In the first step, the precursor of the rod-shaped catalyst is decomposed, and the decomposed product of the precursor (metal vapor or metal fine particles obtained by agglomeration of metal vapor) is uniformly dispersed in the reaction system.

According to the findings of the present inventors, the metal vapor does not function as a rod-shaped catalyst, but the metal fine particles obtained by agglomeration thereof function as a rod-shaped catalyst. Therefore, when no metal fine particles are present in the system during the thermal decomposition of the first carbon source in the first step (for example, when the decomposition product of the precursor is present as metal vapor), only the carbon spherical particles are A reaction product is obtained which is formed to contain carbon spherical particles and decomposition products of the precursor. Further, when fine metal particles are present in the system during thermal decomposition of the first carbon source in the first step, carbon rod-shaped particles are formed to obtain a reaction product containing carbon spherical particles and carbon rod-shaped particles. be done.

In the second step of this embodiment, a second carbon source is added to the reaction product. When the reaction product contains carbon rod-shaped particles, the second carbon source causes the carbon rod-shaped particles to grow radially. When the reaction product does not contain carbon rod-shaped particles, carbon rod-shaped particles are generated from the second carbon source starting from the rod-shaped catalyst. Specifically, for example, when the reaction product contains carbon spherical particles and metal vapor, the metal vapor aggregates due to the temperature drop due to the addition of the second carbon source, etc., and metal fine particles (that is, rod-shaped catalyst) are generated. Then, carbon rod-shaped particles are generated starting from the fine metal particles. Thus, in the second step, a carbon composite containing carbon spherical particles and carbon rod-like particles is obtained.

In the production method of the present embodiment, the decomposition product of the rod-shaped catalyst precursor is uniformly dispersed in the reaction system in the first step. Therefore, according to the production method of the present embodiment, a carbon composite having excellent electrical conductivity in which the carbon spherical particles and the carbon rod-shaped particles are uniformly dispersed is produced.

Each step of the manufacturing method of this embodiment will be described in detail below.

(First step)
The first step is a step of reacting a mixed gas containing a first carbon source and a precursor of a rod-shaped catalyst to obtain a reaction product containing carbon spherical particles.

The first carbon source may be any compound capable of forming carbon spherical particles by thermal decomposition. Examples of the first carbon source include saturated hydrocarbons such as methane, ethane, propane and butane; unsaturated hydrocarbons having double bonds such as ethylene, propylene, butene and butadiene; Unsaturated hydrocarbons having bonds, aromatic hydrocarbons such as benzene, toluene and xylene can be used. As the first carbon source, vaporized oily hydrocarbons such as gasoline, kerosene, light oil and heavy oil can also be used.

When the first carbon source generates a large amount of heat during thermal decomposition, it is preferable because the reaction system can be easily maintained at a high temperature. From this viewpoint, the first carbon source is preferably an unsaturated hydrocarbon, more preferably an unsaturated hydrocarbon having a triple bond, and particularly preferably acetylene.

Examples of rod-shaped catalysts include fine metal particles made of metals such as iron, cobalt, nickel, molybdenum, titanium, vanadium, and chromium. Iron microparticles are preferable from the viewpoint of the price of the body and the like.

The precursor of the rod-shaped catalyst may be a metal compound containing the metal that constitutes the rod-shaped catalyst. As a precursor of the rod-shaped catalyst, for example, an inorganic metal compound, an organic metal compound, or the like can be used. Examples of inorganic metal compounds include iron chloride, iron bromide, iron oxide, cobalt carbonate, cobalt chloride, cobalt bromide, cobalt oxide, nickel chloride, nickel bromide, and nickel oxide. Examples of organometallic compounds include ferrocene, nickelocene, cobaltocene, iron carbonyl, iron acetylacetonate, and iron oleate.

The precursor of the rod-shaped catalyst is preferably a compound that can be gas-mixed with the first carbon source by vaporization. As the precursor of the rod-shaped catalyst, an organometallic compound is preferable, and ferrocene is particularly preferable, because it is relatively easy to vaporize and easy to prevent contamination with foreign elements.

The content of the precursor of the rod-shaped catalyst is not particularly limited. For example, the content of the metal element in the precursor is 0.01 parts by mass or more with respect to 100 parts by mass of carbon atoms in the first carbon source. The amount may be The content of the metal element in the precursor of the rod-shaped catalyst is preferably 0.03 parts by mass or more, more preferably 0.1 parts by mass or more, relative to 100 parts by mass of carbon atoms in the first carbon source, More preferably, it is 0.3 parts by mass or more. The content of the metal element in the precursor of the rod-shaped catalyst may be, for example, 100 parts by mass or less, preferably 30 parts by mass or less, with respect to 100 parts by mass of carbon atoms in the first carbon source. It is more preferably 10 parts by mass or less, still more preferably 3 parts by mass or less.

The gas mixture of the first step may further contain a promoter. Examples of the promoter include sulfur components such as elemental sulfur and sulfur-containing compounds containing sulfur atoms (eg, thiophene, hydrogen sulfide, carbon disulfide).

The content of the promoter may be, for example, 0.1 parts by mass or more, preferably 0.3 parts by mass or more, and more preferably 1 part by mass or more, relative to 100 parts by mass of the precursor of the rod-shaped catalyst. . The content of the promoter may be, for example, 100 parts by mass or less, preferably 30 parts by mass or less, and more preferably 10 parts by mass or less with respect to 100 parts by mass of the precursor of the rod-shaped catalyst.

The mixed gas in the first step may further contain other components than those mentioned above. Other components include, for example, inert gases such as argon, helium, and nitrogen; oxidizing gases such as oxygen, air, and water vapor; and reducing gases such as hydrogen and ammonia.

The mixed gas in the first step may be obtained, for example, by a mixing step of mixing the above components to obtain a mixed gas. The mixing step may be, for example, a step of mixing a first gas containing a first carbon source and a second gas containing a precursor of a rod-shaped catalyst.

When the mixed gas contains a co-catalyst, the co-catalyst may be blended with the first gas or the second gas, but may be blended with the second gas. preferable. Also, the mixing step may be a step of further mixing a third gas containing a co-catalyst.

In the first step, the mixed gas is reacted at a temperature equal to or higher than the thermal decomposition temperature of the first carbon source. The reaction temperature T ₁ (°C) in the first step may be, for example, 1200°C or higher, preferably 1300°C or higher, and more preferably 1400°C or higher. The upper limit of the reaction temperature T ₁ (°C) is not particularly limited. The reaction temperature T ₁ (° C.) may be, for example, 2500° C. or lower, 2300° C. or lower, or 2000° C. or lower. In this specification, the reaction temperature _T1 indicates the maximum temperature when the temperature distribution is measured by moving the thermocouple on the central axis of the first reaction section where the first step is performed. When the first reaction section is not axially symmetrical, the maximum temperature when the temperature distribution is measured along the approximate center of the channel can be regarded as the reaction temperature _T1 .

In a preferred embodiment, the first step is a step of obtaining a reaction product containing carbon spherical particles, a rod-shaped catalyst, and carbon rod-shaped particles (hereinafter sometimes referred to as step (1-1)), good.

In step (1-1), for example, in the first step, the metal vapor generated by the decomposition of the precursor of the rod-shaped catalyst aggregates to form the rod-shaped catalyst (fine metal particles). _1. It can be carried out by adjusting the volume of the first reaction section, the flow rate of the mixed gas, and the like. Specifically, for example, by lowering the reaction temperature _T1 , lengthening the residence time of the mixed gas in the first reaction section, etc., the metal vapor tends to aggregate, and the step (1-1) It becomes easy to obtain a reaction product.

In another preferred embodiment, the first step is a step of obtaining a reaction product containing carbon spherical particles and a decomposed product of a precursor of a rod-shaped catalyst and not containing carbon rod-shaped particles (hereinafter referred to as step (1- 2) may be used).

In the step (1-2), for example, the reaction temperature T ₁ , the first reaction It can be carried out by adjusting the volume of the part, the flow rate of the mixed gas, and the like. Specifically, for example, by increasing the reaction temperature _T1 , shortening the residence time of the mixed gas in the first reaction section, etc., it becomes difficult for the metal vapor to aggregate, and the step (1-2) It becomes easy to obtain a reaction product.

In the step (1-2), the reaction product containing the carbon spherical particles and the metal vapor may be subjected to the second step, and after the carbon spherical particles are formed, the metal vapor is aggregated to form the carbon spherical particles and the metal microparticles. may be subjected to the second step.

(Second step)
The second step is a step of adding a second carbon source to the reaction product produced in the first step and reacting them to obtain a carbon composite containing carbon spherical particles and carbon rod-like particles.

The second carbon source may be any compound that can be thermally decomposed in the presence of the rod-shaped catalyst to form carbon rod-shaped particles. Examples of the second carbon source include saturated hydrocarbons such as methane, ethane, propane and butane; unsaturated hydrocarbons having double bonds such as ethylene, propylene, butene and butadiene; Unsaturated hydrocarbons having bonds, aromatic hydrocarbons such as benzene, toluene and xylene, alcohols, ethers, carbon monoxide and the like can be used.

Carbon rod-shaped particles suppress the generation of carbon by-products due to non-catalytic reactions that take precedence at high temperatures, and promote catalytic reactions that take precedence at low temperatures. ) tends to be easily formed. The second carbon source is preferably a compound that is more stable than the first carbon source and generates less heat during thermal decomposition, from the viewpoint of easily maintaining the reaction system at a temperature suitable for forming carbon rod-shaped particles. As the second carbon source, saturated hydrocarbons, unsaturated hydrocarbons having double bonds and aromatic hydrocarbons are preferred, and methane, ethylene, toluene and the like can be particularly preferably used.

The amount of the second carbon source added is such that, for example, the amount of carbon atoms in the second carbon source is 1 mass with respect to 100 parts by mass of carbon atoms in the first carbon source supplied in the first step. The amount may be 1 part or more. The amount of carbon atoms in the second carbon source may be, for example, 1 part by mass or more, preferably 3 parts by mass or more, more preferably 10 parts by mass with respect to 100 parts by mass of carbon atoms in the first carbon source. It is at least 30 parts by mass, more preferably at least 30 parts by mass. Further, the amount of carbon atoms in the second carbon source may be, for example, 10000 parts by mass or less, preferably 3000 parts by mass or less, more preferably 100 parts by mass of carbon atoms in the first carbon source. is 1000 parts by mass or less, more preferably 300 parts by mass or less.

In the second step, components other than the second carbon source may be further added. Other components include, for example, inert gases such as argon, helium, and nitrogen, hydrogen, water vapor, carbon dioxide, and the like. The inert gas can be used as a diluent, and the addition of the inert gas can reduce the concentration of the carbon source and suppress tar formation. Hydrogen is also useful for controlling the equilibrium between the hydrogenation reaction and the dehydrogenation reaction. Steam and carbon dioxide can also play a role in removing carbon by-products on the rod-shaped catalyst to maintain catalytic activity.

When adding an inert gas to the reaction product, the amount of the inert gas added is not particularly limited, and may be, for example, 10 parts by mass or more with respect to 100 parts by mass of carbon atoms in the second carbon source, Preferably, it is 30 parts by mass or more. The amount of the inert gas added may be, for example, 1000 parts by mass or less, preferably 400 parts by mass or less with respect to 100 parts by mass of carbon atoms in the second carbon source.

When hydrogen is added to the reaction product, the amount of hydrogen added is not particularly limited, and may be, for example, 1 part by mass or more, preferably 3 parts by mass, with respect to 100 parts by mass of carbon atoms in the second carbon source. parts or more, more preferably 10 parts by mass or more, and still more preferably 30 parts by mass or more. In addition, the amount of hydrogen added may be, for example, 5000 parts by mass or less, preferably 3000 parts by mass or less, more preferably 1000 parts by mass or less, with respect to 100 parts by mass of carbon atoms in the second carbon source. Preferably, it is 300 parts by mass or less.

When carbon dioxide is added to the reaction product, the amount of carbon dioxide added is not particularly limited, and may be, for example, 1 part by mass or more, preferably 1 part by mass or more with respect to 100 parts by mass of carbon atoms in the second carbon source. It is 3 parts by mass or more. The amount of carbon dioxide added may be, for example, 100 parts by mass or less, preferably 30 parts by mass or less, with respect to 100 parts by mass of carbon atoms in the second carbon source.

When steam is added to the reaction product, the amount of steam added is not particularly limited, and may be, for example, 0.01 parts by mass or more, preferably 100 parts by mass of carbon atoms in the second carbon source. It is 0.1 parts by mass or more. The amount of water vapor to be added may be, for example, 100 parts by mass or less, preferably 10 parts by mass or less with respect to 100 parts by mass of carbon atoms in the second carbon source.

The second carbon source and other components may be added individually to the reaction product, or may be premixed and then added to the reaction product.

In the second step, the reaction product and the second carbon source are reacted at a temperature equal to or higher than the thermal decomposition temperature of the second carbon source. The reaction temperature T ₂ (°C) may be, for example, 800°C or higher, preferably 900°C or higher, and more preferably 1000°C or higher. The upper limit of the reaction temperature T ₂ (°C) is not particularly limited. The reaction temperature T ₂ (°C) may be, for example, less than 1400°C, preferably less than 1350°C, more preferably less than 1300°C. In this specification, the reaction temperature _T2 indicates the maximum temperature when the temperature distribution is measured by moving the thermocouple on the central axis of the second reaction section where the second step is performed. If the second reaction section is not axially symmetrical, the maximum temperature when the temperature distribution is measured along the approximate center of the channel can be regarded as the reaction temperature _T2 .

The reaction temperature T ₂ (°C) in the second step is preferably lower than the reaction temperature T ₁ (°C) in the first step. The difference (T ₁ −T ₂ ) between the reaction temperature T ₁ and the reaction temperature T ₂ is preferably 100° C. or higher, more preferably 300° C. or higher, still more preferably 500° C. or higher. As a result, the carbon spherical particles and the carbon rod-like particles are efficiently formed in each step, and the above effects are exhibited more remarkably.

When the first step is step (1-1), the second step may be a step of radially growing carbon rod-shaped particles in the reaction product. At this time, the second carbon source may be used only for the growth of the carbon rod-shaped particles in the radial direction, and in addition to the growth of the carbon rod-shaped particles in the radial direction, the formation of the carbon spherical particles and the growth of the carbon spherical particles. , the formation of carbon rod-shaped particles, the growth of carbon rod-shaped particles in the length direction, and the like.

When the first step is step (1-1), in the second step, a solid columnar shape or a hollow cylindrical carbon rod shape having an outer diameter three times or more the inner diameter is formed by growth in the radial direction. Particles are easily formed.

When the first step is the step (1-2), the second step is, if necessary, aggregating the metal vapor in the reaction product to form a rod-shaped catalyst (fine metal particles) to form a rod-shaped catalyst. It may be a step of forming carbon rod-shaped particles starting from the catalyst. At this time, the second carbon source may be used only for the formation of carbon rod-shaped particles, in addition to the formation of carbon rod-shaped particles, the formation of carbon spherical particles, the growth of carbon spherical particles, the radial direction of It may be provided for growth in the length direction and the like.

When the first step is step (1-2), in the second step, hollow cylindrical carbon rod-shaped particles having an outer diameter less than three times the inner diameter are likely to be formed, preferably single-walled carbon nanotubes. It is formed.

The production method of the present embodiment includes, for example, a first reaction section, and a first supply path that supplies a mixed gas containing a first carbon source and a precursor of a rod-shaped catalyst to the first reaction section. , a second reaction section, a second supply channel for supplying the reaction product obtained in the first reaction section to the second reaction section, and a second carbon source for supplying the second reaction section and a third supply channel.

The production apparatus may have heating means in the first reaction section and the second reaction section. In addition, in the production method of the present embodiment, the thermal decomposition of the first carbon source and/or the second carbon source may be an exothermic reaction. The reaction section and/or the second reaction section may not have heating means, and preferably have heat retaining means (for example, heat insulating material).

FIG. 1 is a schematic cross-sectional view showing one mode of a carbon composite manufacturing apparatus. The carbon composite manufacturing apparatus 100 shown in FIG. A second supply path L2 that supplies the reaction product obtained in the first reaction section 1 to the second reaction section 2, and a third supply path that supplies the second carbon source to the second reaction section 2. and L3. The manufacturing apparatus 100 also includes a heating means 10 for heating the first reaction section 1 and a heating means 20 for heating the second reaction section 2 .

The manufacturing apparatus 100 may be airtightly configured with heat-resistant members. Since the reaction temperature T1 is high, the first reaction section ₁ is preferably made of a material with high heat resistance (for example, boron nitride, graphite, ceramics, etc.). The heating means 10 for heating the first reaction section 1 is not particularly limited, and may be, for example, one that heats the first reaction section 1 by electrical heating using carbon, ceramics, or the like, dielectric heating, or the like. When the thermal decomposition of the first carbon source is an exothermic reaction, a heat insulating material is placed around the first reaction section 1 to heat the inside of the first reaction section 1 by the heat of decomposition of the first carbon source. may

The second reaction section 2 may be made of the same material as the first reaction section 1, or may be made of quartz glass, ceramics, metal members, or the like. The heating means 20 for heating the second reaction section 2 is not particularly limited, and various electric furnaces, dielectric heating furnaces, etc. can be used without particular limitations. Moreover, when a high-temperature reaction product is supplied from the second supply path L2, by arranging a heat insulating material around the second reaction section 2, the heat of the reaction product can be effectively used. The second supply path L2 is preferably shorter than the first reaction section 1 and the second reaction section 2 from the viewpoint of avoiding a temperature drop of the reaction product. In addition, since the reaction in the second reaction section 2 has a lower reaction temperature and a lower reaction rate than the reaction in the first reaction section 1, from the viewpoint of ensuring a sufficient residence time in the second reaction section 2, It is preferable that the volume of the second reaction section 2 is larger than the volume of the first reaction section 1 .

The material of the heat insulating material is not particularly limited, and known heat insulating materials such as refractory heat insulating bricks, ceramic fibers, and calcium silicate heat insulating materials can be used, for example.

The carbon composite produced by the production method of the present embodiment (hereinafter also referred to as the carbon composite of the present embodiment) contains carbon spherical particles and carbon rod-shaped particles. The carbon spherical particles may be carbon black and the carbon rod particles may be carbon nanofibers and/or carbon nanotubes.

The structure of the carbon composite of the present embodiment can be appropriately controlled depending on the purpose.

The smaller the particle size of the carbon spherical particles in the carbon composite, the larger the specific surface area, which tends to facilitate the formation of conductive paths with the addition of a small amount. In addition, the larger the particle diameter of the carbon spherical particles in the carbon composite, the higher the bulk density, which tends to make it easier to increase the amount added to the resin. The average particle diameter of the carbon spherical particles in the carbon composite is not particularly limited, but may be, for example, 10 to 1000 nm, preferably 10 to 300 nm, more preferably 10 to 100 nm, still more preferably 10 to 50 nm. In this specification, the average particle size of the carbon spherical particles is obtained by observing 100 particles with an electron microscope image, calculating the equivalent circle diameter from the area of each particle, and calculating the area average of the equivalent circle diameters. shows the value obtained by

The carbon rod-shaped particles in the carbon composite tend to have a larger specific surface area as the diameter is smaller, making it easier to form a conductive path with the addition of a small amount. In addition, the carbon rod-shaped particles in the carbon composite tend to have a higher bulk density as the diameter increases, making it easier to increase the amount added to the resin. The average diameter of the carbon rod-shaped particles in the carbon composite is not particularly limited, but may be, for example, 0.6 nm or more, preferably 1 nm or more. Also, the average diameter of the carbon rod-shaped particles in the carbon composite may be, for example, 300 nm or less, preferably 100 nm or less, and more preferably 50 nm or less. In the present specification, the average diameter of carbon rod-shaped particles is a value obtained by observing 100 rod-shaped particles with an electron microscope image, taking the width of each particle as the diameter, and calculating the number average of the diameters. .

The carbon rod-shaped particles in the carbon composite tend to form conductive paths more easily when added in small amounts as the length increases. The average length of the carbon rod-shaped particles in the carbon composite is not particularly limited, but may be, for example, 0.3 μm or longer, preferably 1 μm or longer, and more preferably 3 μm or longer. Also, the average length of the carbon rod-shaped particles in the carbon composite may be, for example, 300 μm or less, preferably 100 μm or less, and more preferably 30 μm or less. In this specification, the average length of carbon rod-shaped particles is obtained by observing 100 rod-shaped particles with an electron microscope image, determining the length of each particle, and calculating the length average of the length. indicate a value.

When the content ratio of the carbon spherical particles in the carbon composite is high, the dispersibility tends to improve and the addition to the resin tends to become easier. Further, when the content ratio of carbon rod-shaped particles in the carbon composite is high, there is a tendency that a small amount of addition tends to facilitate the formation of a conductive path. The content ratio of the carbon rod-shaped particles in the carbon composite may be, for example, 3 parts by mass or more, preferably 10 parts by mass or more, more preferably 30 parts by mass with respect to 100 parts by mass of the carbon spherical particles in the carbon composite. Department or above. Further, the content ratio of the carbon rod-shaped particles in the carbon composite may be, for example, 3000 parts by mass or less, preferably 1000 parts by mass or less, more preferably 100 parts by mass or less with respect to 100 parts by mass of the carbon spherical particles in the carbon composite. It is 300 mass parts or less.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments.

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples.

(Example 1)
A carbon composite was produced using the manufacturing apparatus 100 in which the first supply path L1 is an alumina nozzle having an inner diameter of 4 mm and the distance between the outlet of the first supply path L1 and the heating means 10 is 5 cm.
Specifically, a mixed gas containing acetylene gas, ferrocene, and sulfur is supplied to the first reaction section 1 from the first supply path L1, and a mixed gas of methane and hydrogen is supplied from the third supply path L3. It was supplied to the second reaction section 2, and the black powder was recovered downstream of the second reaction section 2 using a membrane filter. The mixed gas supplied to the first reaction unit 1 contains 1.5 parts by mass of iron element in ferrocene and 0.002 parts by mass of sulfur per 100 parts by mass of carbon atoms in acetylene gas. The component ratio was adjusted so that In addition, the mixed gas supplied to the second reaction section 2 was adjusted so that the amount of hydrogen was 111 parts by mass with respect to 100 parts by mass of carbon atoms in methane.
In Example 1, the reaction temperature _T1 was 1564°C and the reaction temperature _T2 was 1000°C.

When the obtained black powder was observed with an SEM, it was confirmed that the black powder was a composite of carbon spherical particles (carbon black) and carbon rod-like particles (carbon nanofibers).

Further, when the carbon composite of Example 1 was observed by SEM in a plurality of fields of view, carbon spherical particles (carbon black) and carbon rod-shaped particles (carbon nanofibers) were uniformly dispersed in all fields of view. was confirmed. 2 is a diagram showing an example of an SEM observation image of the carbon composite of Example 1. FIG.

<Measurement of surface resistivity>
4 mg of the carbon composite of Example 1 was dispersed in 20 mL of a 0.5 wt % sodium dodecylbenzenesulfonate (SDBS) aqueous solution using ultrasonic waves to prepare a dispersion liquid. The resulting dispersion was suction filtered and washed with 50 mL of warm water to produce a circular carbon composite sheet with a diameter of 18 mm. When the surface resistivity of the obtained carbon composite sheet was measured, it was 67.7Ω/□.

(Comparative example 1)
A black powder was obtained in the same manner as in Example 1, except that the gas supplied from the first supply path L1 was changed to acetylene gas, and the gas supplied from the third supply path L3 was changed to argon gas.

When the obtained black powder was observed with SEM, it was confirmed that the obtained black powder was only carbon black. 3 is a diagram showing an SEM observation image of the black powder of Comparative Example 1. FIG.

4 mg of the resulting black powder was dispersed in a 0.5 wt % SDBS aqueous solution to prepare a dispersion. The resulting dispersion was suction filtered and washed with 50 mL of hot water to prepare a circular sheet with a diameter of 18 mm. The surface resistivity of the obtained sheet was measured and found to be 163Ω/□.

(Comparative example 2)
Black powder was produced in the same manner as in Example 1, except that the gas supplied from the first supply path L1 was changed to acetylene gas, and a mixed gas containing ferrocene and sulfur was supplied in the middle of the second supply path L2. got a body

When the obtained black powder was observed by SEM, it was confirmed to be a composite containing carbon spherical particles and carbon rod-like particles.

Further, when the carbon composite of Comparative Example 2 was subjected to SEM observation in a plurality of fields, the existence ratio of carbon spherical particles and carbon rod-shaped particles differed greatly in each field, and carbon nanotubes were scarcely observed in some fields. 4(a) and 4(b) are diagrams showing examples of SEM observation images of the carbon composite of Comparative Example 2. FIG.

Using the carbon composite of Comparative Example 2, a carbon composite sheet was produced in the same manner as in Example 1. When the surface resistivity of the obtained carbon composite sheet was measured, it was 107Ω/□.

From the results of Example 1 and Comparative Examples 1 and 2, it can be seen that the method for producing a carbon composite of the present invention can provide a carbon composite in which carbon spherical particles and carbon rod-like particles are uniformly dispersed and which has excellent electrical conductivity. confirmed.

(Example 2)
The procedure was the same as in Example 1, except that the first supply path L1 was an alumina nozzle with an inner diameter of 0.8 mm, and that the distance between the outlet of the first supply path L1 and the heating means 10 was 2 cm. to obtain a black powder.

When the obtained black powder was observed with an SEM, it was confirmed to be a carbon composite containing carbon spherical particles (carbon black) and carbon rod-like particles (carbon nanotubes). Further, when the carbon composite of Example 2 was analyzed by Raman spectroscopy, it was confirmed that it contained single-walled carbon nanotubes.

From the results of Examples 1 and 2, in the method for producing a carbon composite of the present invention, by adjusting the production conditions, a composite containing carbon black and carbon nanofibers and a composite containing carbon black and carbon nanotubes can be produced. , can be easily produced separately.

DESCRIPTION OF SYMBOLS 1... 1st reaction part, 2... 2nd reaction part, 10, 20... Heating means, 100... Manufacturing apparatus.

Claims (10)

A manufacturing method for manufacturing a carbon composite containing carbon spherical particles and carbon rod-shaped particles,
a first step of reacting a mixed gas containing a first carbon source and a rod-shaped catalyst precursor to obtain a reaction product containing carbon spherical particles;
a second step of adding a second carbon source to the reaction product produced in the first step and reacting it to obtain a carbon composite containing carbon spherical particles and carbon rod-like particles;
A method of manufacturing a carbon composite, comprising: 2. The manufacturing method according to claim 1, wherein said first step is a step of obtaining a reaction product containing carbon spherical particles and decomposition products of said precursor from said mixed gas. The first step is a step of reacting the mixed gas at a temperature _T1 ,
3. The production method according to _claim 1 or 2, wherein said second step is a step of reacting a mixture of said reaction product and said second carbon source at a temperature _T2 lower than said T1. 4. The manufacturing method according to claim 3, wherein the difference (T ₁ −T ₂ ) between said T ₁ and said T ₂ is 100° C. or more. 5. Any one of claims 1 to 4, further comprising a mixing step of mixing a first gas containing the first carbon source and a second gas containing the precursor to obtain the mixed gas. The manufacturing method described in the item. The production method according to any one of claims 1 to 5, wherein the precursor contains iron atoms. The manufacturing method according to any one of claims 1 to 6, wherein the precursor comprises ferrocene. 8. The production method according to claim 7, wherein the mixed gas further contains at least one sulfur component selected from the group consisting of elemental sulfur and sulfur-containing compounds containing sulfur atoms. The production method according to any one of claims 1 to 8, wherein said first carbon source comprises acetylene. A production apparatus for producing a carbon composite containing carbon spherical particles and carbon rod-shaped particles,
a first reaction section;
a first supply passage for supplying a mixed gas containing a first carbon source and a precursor of a rod-shaped catalyst to the first reaction section;
a second reaction section;
a second supply path for supplying the reaction product obtained in the first reaction section to the second reaction section;
a third supply channel for supplying a second carbon source to the second reaction section;
manufacturing equipment.

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