JP2003306835A - Vapor-grown carbon fiber and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To economically produce a vapor-grown carbon fiber with high productivity and further produce the carbon fiber by using an economical catalyst with a small amount of the added catalyst. <P>SOLUTION: The method for producing the vapor-grown carbon fiber comprises carrying out a pyrolytic reaction of an organic compound and an inorganic transition metal compound used as main raw materials. In the method, a transition metal chloride is used as the inorganic transition metal compound and the amount of the transition metal chloride used is 0.01-20 mass% based on the organic compound. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a vapor-grown carbon fiber by a thermal decomposition reaction of an organic compound as a carbon source and an inorganic transition metal compound as a catalyst, the carbon fiber and its use. Is.

[0002]

2. Description of the Related Art As a method for producing fine carbon fibers, an organic compound such as benzene is used as a raw material, an organic transition metal compound such as ferrocene is used as a metal catalyst, and these are introduced into a high temperature reactor together with a carrier gas. A method of forming fine carbon fibers on a substrate (JP-A-60-277).
No. 00), a method of generating in a floating state (Japanese Patent Laid-Open No. Sho 60).
No. 54998), or a method of growing on a reactor wall (Patent 2778434). The carbon fibers produced by these methods are called vapor grown carbon fibers. Method using an inorganic transition metal compound that is relatively easy to evaporate as a catalyst (Japanese Patent Publication No. 4-13449)
However, this method has a problem in productivity from the viewpoint of effective utilization of the catalyst, because the catalyst must be added at a high concentration depending on the type of the catalyst used.

When the catalyst is added in a high concentration, a large amount of metal is mixed in the product, and there is a problem that it cannot be removed sufficiently even in the heat treatment step after the reaction. Affect. In addition, when it is necessary to heat treat the carbon fibers, heating the carbon fibers mixed with a large amount of metal at a high temperature causes deposition of impurities metals and damages the apparatus, which also causes a problem of reducing productivity. is there.

[0004]

As a method for generating fine particles of a transition metal catalyst used in the production of vapor-phase pyrolysis carbon fiber, a method using ferrocene, which is an organic transition metal compound, as a catalyst raw material is generally carried out. However, this method
Utilizing the sublimability of ferrocene, ferrocene is heated to evaporate, and it is entrained in a carrier gas and supplied to a reactor (production zone), where iron catalyst fine particles are generated by thermal decomposition of ferrocene. Method or ferrocene as a raw material (organic compound as a carbon source)
And then evaporated and supplied to a reaction device, where iron catalyst fine particles are generated by thermal decomposition of ferrocene. These methods are excellent in that they can be uniformly dispersed and supplied into the reaction apparatus by gasifying them by utilizing the sublimation property of ferrocene, and are widely used industrially. However, ferrocene used in these methods is expensive, and it is desired to use a cheaper catalyst raw material in order to industrially produce a large amount of carbon fiber at low cost.

As the transition metal compound, there are carbonyl compounds, carboxylic acid compounds and the like in addition to ferrocene, but all of them have a low thermal decomposition temperature and are easily decomposed in the reaction apparatus to form fine transition metal fine particles. Is difficult,
It cannot be an effective carbon fiber forming reaction catalyst. As the inorganic transition metal compound, oxides, glass compounds, sulfur compounds, fluorides, bromides, etc. are known, but it is difficult to gasify any of them. In addition, a compound whose thermal decomposition temperature is lower than the evaporation temperature cannot be supplied as a gas to the reaction device because the thermal decomposition occurs before gasification, and cannot be a carbon fiber forming reaction catalyst.

An object of the present invention is to produce carbon fibers economically and with high productivity, and to produce carbon fibers using an economical catalyst with a small amount of catalyst added.

[0007]

In order to solve the above problems, the inventors of the present invention have made extensive studies on the type of catalyst and the supply method, and as a result, by using an inorganic transition metal chloride such as iron chloride as a catalyst, We have completed a technology to reduce the amount of catalyst added and achieved high productivity. The present invention has the following configurations.

That is, according to the present invention, 1) an organic compound and an inorganic transition metal compound are used as main raw materials,
In the method for producing a vapor-grown carbon fiber by these thermal decomposition reactions, a transition metal chloride is used as the inorganic transition metal compound, and the transition metal chloride is added in an amount of 0.01 to 0.01 to the organic compound.
20% by mass of a vapor-grown carbon fiber, which is characterized by using 2%, 2) a step of dissolving a transition metal chloride in an organic compound and evaporating it to obtain a mixed gas thereof, and then mixing a carrier gas And the step of supplying to the carbon fiber production zone, the method for producing the vapor grown carbon fiber according to the above 1, 3) a step of obtaining a mixed gas of a carrier gas and a vaporized gas of an organic compound, and then a transition metal chloride The method for producing a vapor-grown carbon fiber as described in 1 above, including the step of mixing a vaporized gas and supplying it to the carbon fiber production zone. 4) A transition metal chloride solution is sprayed to produce transition metal chloride fine particles. A step of obtaining a mixed gas of a carrier gas and a vaporized gas of an organic compound, the transition metal chloride fine particles, a carrier gas and a vaporized gas of the organic compound to form carbon fibers The method for producing a vapor-grown carbon fiber according to 1 above, which further comprises: 5) The transition metal chloride is at least one transition metal chloride selected from the group consisting of iron, nickel, cobalt, molybdenum, and vanadium. The above-mentioned 1 characterized by being a thing
5. The method for producing a vapor-grown carbon fiber according to any one of 1 to 4, 6) The vapor phase according to 5, wherein the transition metal chloride is at least one selected from the group consisting of iron chloride, nickel chloride, and cobalt chloride. Method for producing grown carbon fiber, 7) The above-mentioned 1 in which the organic compound is an aromatic compound, acetylene, ethylene, butadiene, or a mixture thereof.
5) A method for producing a vapor-grown carbon fiber according to any one of 5 to 8), 8) A method for producing a vapor-grown carbon fiber according to 7, wherein the aromatic compound is benzene, toluene, xylene or naphthalene, 9) An organic compound 3. In the step of obtaining a mixed gas of these by dissolving a transition metal chloride in, and evaporating this, methanol, ethanol, and acetone are added as dissolution aids, and the vapor phase according to the above 2 is characterized. Manufacturing method of grown carbon fiber, 10) Vapor grown carbon fiber manufactured by the manufacturing method according to any one of the above 1 to 9, 11) Fiber outer diameter is 1 to 500 nm, fiber length is 0.5
The vapor-grown carbon fiber according to 10 above, which is ˜100 μm, 12) The vapor-grown carbon fiber produced by the production method according to 1 above, wherein the transition metal chloride is iron chloride, wherein the fiber outer diameter is 1 -500 nm, fiber length is 0.5-100 μm, and iron content in the fiber is 5 mass% or less, vapor-grown carbon fiber, 13) The resin described in any one of 10 to 12 above. A resin composition containing vapor grown carbon fiber, and 14) a secondary battery using the electrode material containing vapor grown carbon fiber according to any one of 10 to 12 above.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

The main raw materials used for producing the carbon fiber of the present invention are an organic compound as a carbon source and a transition metal chloride.

As the carbon source, any organic compound containing carbon having a vaporization temperature lower than its decomposition temperature and containing carbon can be applied. Specifically, aromatic compounds such as benzene, toluene and xylene, acetylene, ethylene and methane are used. Although linear hydrocarbons such as ethane, propane, butane, and butadiene, alicyclic hydrocarbons, alcohols such as methanol, and methanol can be used, aromatic compounds are preferable, and benzene and xylene are more preferable. Further, these carbon sources can be used alone or in a mixture of two or more kinds.

It is effective to use a transition metal chloride as a catalyst raw material. It is a transition metal chloride such as iron, nickel, cobalt, molybdenum, vanadium, which has a subliming property and a low boiling point as compared with these oxides, nitric oxides, sulfates, fluorides, bromides, etc. Therefore, it is possible to easily gasify. In addition, since the thermal decomposition temperature and the reduction reaction temperature with hydrogen are higher than the thermal decomposition reaction temperature of organic transition metal compounds, fine transition metal fine particles are produced in the reactor, which is effective as a carbon fiber production reaction catalyst. To function.

For example, benzene is converted into carbon (cluster)
In the case where the source, ferric chloride as a catalyst source, and hydrogen gas as a carrier gas, these mixed gases are supplied to the reactor, ferric chloride is reduced with hydrogen gas at about 350 ° C.,
Iron atoms are released. The iron atoms gradually increase in size due to repeated collisions and agglomerations, and when they grow into fine particles of several nanometers, they function as a catalyst for the carbon fiber forming reaction. At the same time, the generation of carbon clusters due to the thermal decomposition reaction of benzene progresses, and this grows using the above iron fine particles as nuclei to form carbon fibers.

As the iron chloride, ferrous chloride (FeCl ₂ ) and ferric chloride (FeCl ₃ ) can be used, and these may be used alone or in combination. Further, a hydrate or anhydrate may be used.

Further, it is possible to further improve the productivity by adding a sulfur source to the raw material. As the sulfur source, elemental sulfur, organic sulfur compounds such as thiophene, and inorganic sulfur compounds such as hydrogen sulfide can be used, and sulfur or thiophene is preferable. Sulfur is more desirable because it is easy to handle. These sulfur and sulfur compounds can be used alone or in combination of two or more kinds.

As a method of supplying the transition metal chloride to the reaction apparatus, for example, a transition metal chloride is dissolved in an organic compound and the mixture gas is evaporated to obtain a mixed gas thereof, and then hydrogen is used as a carrier gas. A method of mixing and supplying to a carbon fiber production furnace, a method of gasifying transition metal chloride and mixing with hydrogen as a carrier gas and supplying to a carbon fiber production furnace, and fine particles obtained by spraying a transition metal chloride solution. There is a method in which a carrier gas and a vaporized gas of an organic compound are supplied together to a carbon fiber production furnace.

(Method of Dissolving Transition Metal Chloride in Organic Compound and Supplying it) Dissolving transition metal chloride in a raw material organic compound and sending this to an evaporator, and the mixed gas evaporated here is fed to a reactor. The method for obtaining the fed carbon fiber is excellent in that a transition metal chloride supply device is not required, and the transition metal chloride can be supplied to the reaction device in a state in which the transition metal chloride and the starting organic compound are uniform. However, the solubility of the transition metal chloride in the starting organic compound is not so great. in this case,
As a dissolution aid, methanol, ethanol, acetone,
Etc. is effective in increasing the solubility. For example, when ferric chloride is dissolved in benzene, by adding 1% by mass of ethanol to benzene, about 0.9% by mass of ferric chloride can be dissolved. This mixed liquid can be evaporated by supplying this mixed liquid to an evaporator and heating it at about 80 ° C. under normal pressure. In this case, it is effective to supply a part of the carrier gas to the evaporator in order to stir the evaporator and improve heat transfer. The mixed gas evaporated here is mixed with the remaining carrier gas by a line mixer, and then sent to the reactor. Further, the carrier gas may be preheated so as to obtain a temperature distribution as uniform as possible in the reactor. In the reactor, the reduction reaction between the transition metal chloride and hydrogen gas occurs, releasing the transition metal atoms, which then collide and
By repeating the aggregation, fine transition metal fine particles are formed. At the same time, the thermal decomposition reaction of the raw material organic compound proceeds to generate carbon clusters, which form carbon fibers with the transition metal fine particles as nuclei.

(Method of Gasifying and Supplying Transition Metal Chloride) The above-mentioned method of supplying transition metal chloride by dissolving it in the raw material organic compound has a limited solubility of the transition metal chloride in the raw material organic compound. Therefore, it is not suitable when it is necessary to obtain a large amount of transition metal fine particles. In this case, a method utilizing the physical properties of the transition metal chloride is advantageous. That is, the boiling point of the transition metal chloride is lower than that of other transition metal compounds. For example, under normal pressure, ferric chloride is 319 ° C. and nickel dichloride is 987.
C., cobalt dichloride is 1049.degree. In the case of supplying these transition metal chlorides by gas, it is not always necessary to heat these transition metal chlorides to the boiling point, and in a state in which these transition metal chlorides are heated to a predetermined temperature,
By supplying the carrier gas, it becomes possible to supply the transition metal chloride gas at a temperature below the boiling point. That is,
Operating pressure, operating temperature of heater containing transition metal chloride,
By changing the supply amount of the carrier gas, an arbitrary amount of transition metal chloride can be supplied. For example, when ferric chloride is used, argon is used as a carrier gas, and when operating at an operating pressure of 0.15 MPa, it is heated to 260 ° C. to give ferric chloride at 0.37 g / min. Can be supplied. In this case, when the reduction reaction between the transition metal chloride and hydrogen gas poses a problem, nitrogen, argon,
It is preferable to use an inert gas such as helium. The transition metal chloride gasified by the heater is mixed with hydrogen as a carrier gas by a line mixer or the like, and then sent to the reactor. Further, the carrier gas may be preheated so as to obtain a temperature distribution as uniform as possible in the reactor.
In the reaction apparatus, a reduction reaction between the transition metal chloride and hydrogen gas occurs, transition metal atoms are released, and the collision and aggregation are repeated, and fine transition metal fine particles are formed. At the same time, the thermal decomposition reaction of the raw material organic compound proceeds,
Carbon clusters are generated, and the carbon fibers are formed by using the transition metal fine particles as nuclei.

(Method of Supplying Fine Particles Obtained by Spraying Transition Metal Chloride Solution) The above-described method of supplying the raw material organic compound by gasifying the transition metal chloride controls the particle size of the fine particles of transition metal. However, in order to improve the utilization efficiency of the catalyst, it is necessary to prolong the life of the transition metal particles having a particle size that acts as a catalyst. A transition metal chloride solution, preferably an aqueous transition metal chloride solution as an aqueous solution, is sprayed to produce transition metal chloride fine particles, which are fed into a reactor and subjected to a reduction reaction with hydrogen gas, whereby the surface of the transition metal chloride fine particles is reduced. The transition metal is generated from. The life of the catalyst is longer than that of the methods described above.

The carbon fiber obtained by the reaction can be used as it is, but in order to reduce impurities to improve the quality and to improve the crystallinity, it is 100 to 1500.
C. preferably 500 to 1400 ° C., more preferably 10 ° C.
After firing at 00 to 1300 ° C, graphitization can be performed by heat treatment at 2000 ° C or higher, preferably 2400 ° C or higher, more preferably 2700 ° C or higher, and particularly preferably 2900 ° C or higher. It is also possible to carry out classification to remove impurities such as granular graphite. In the production method of the present invention, the addition amount of the catalyst can be reduced by using the inorganic transition metal chloride as the catalyst. The inorganic transition metal chloride is added in an amount of 0.01 to 20% by mass, preferably 0.1 to 10% by mass, and more preferably 0.2 to 5% by mass, based on the organic compound as a raw material. Therefore, the carbon fiber obtained from a small amount of the inorganic transition metal chloride has a small amount of transition metal contained as an impurity. For example, when iron chloride is used as the transition metal chloride, the content of iron contained in the carbon fiber becomes about 3 mass% or less after heat treatment (calcination) at about 1000 ° C.

The heating rate of the heat treatment does not particularly affect the performance within the range of the maximum heating rate and the minimum heating rate in the known apparatus. However, from the viewpoint of cost, it is better that the temperature rising rate is faster. The time required to reach the maximum temperature from room temperature is preferably 12 hours or less, more preferably 6 hours or less, and particularly preferably 2 hours or less.

The heat treatment apparatus for firing is an Acheson furnace,
Known devices such as a direct current heating furnace can be used. In addition, these devices are also advantageous in terms of cost. However, the presence of nitrogen gas may reduce the resistance of the powder, or the strength of the carbon material may be reduced by the oxidation by oxygen. Therefore, it is preferable to keep the atmosphere in the furnace at an inert gas such as argon or helium. A furnace of various constructions is preferred. For example, a batch furnace in which the container itself can be evacuated and then replaced with gas, a tubular furnace in which the atmosphere in the furnace can be controlled, or a continuous furnace is used.

As a method for improving the crystallinity of the carbon fiber, known graphitization catalysts such as boron, beryllium, aluminum, silicon and the like can be used, if necessary.

Among them, boron can enter into the graphite network crystal by substituting it with carbon atom, and at that time, the carbon-carbon bond is once cut and then re-bonded to reconstruct the crystal structure. it is conceivable that. Therefore, even for the part where the graphite crystal is slightly disturbed, by reconstructing the crystal structure,
It is considered that it becomes possible to make highly crystalline particles. When the carbon film layer contains boron (boron element), it means that a part of boron is solid-solved and exists between the carbon surface and the layer between the carbon hexagonal mesh plane laminates, or the carbon atom and the boron atom are partially replaced. State.

The boron compound may be boron by heating.
Any substance that produces
Solids and liquids such as arsenic oxides and organic boron oxides
May be a gas, for example, simple B, boric acid (H₃B
O₃), Borate, boron oxide (B ₂O₃), Boron carbide
(B_FourC), BN, etc. can be used.

The amount of the boron compound added is not limited because it depends on the chemical and physical properties of the boron compound used. For example, when boron carbide (B ₄ C) is used, the carbon powder to be heat treated is used. In the range of 0.05 to 10% by mass, preferably 0.1 to 5% by mass.

A preferred form of the vapor grown carbon fiber of the present invention is a branched fiber, but the branched portion has a hollow structure in which all the fibers including the branched portion communicate with each other. Therefore, the carbon layer forming the cylindrical portion of the fiber is continuous. The hollow structure is a structure in which a carbon layer is wound in a cylindrical shape and is not a perfect cylinder, has a partially cut portion, or has two laminated carbon layers bonded to one layer. Including. Further, the cross section of the cylinder is not limited to a perfect circle but includes an ellipse and a polygonal one. Regarding the crystallinity of the carbon layer, the interplanar spacing d ₀₀₂ of the carbon layer is not limited. Incidentally, a preferable one has d ₀₀₂ of 0.33 by X-ray diffraction method.
It is 9 nm or less, more preferably 0.338 nm or less, and the thickness Lc of the crystal in the C-axis direction is 40 nm or less. The vapor grown carbon fiber of the present invention has a fiber outer diameter of 500 n.
A carbon fiber having an m or less and an aspect ratio of 10 or more,
Preferably, the fiber outer diameter is 50 to 500 nm, and the fiber length is 1 to 10.
0 μm (aspect ratio 2 to 2000), or fiber outer diameter 2 to 50 nm and fiber length 0.5 to 50 μm (aspect ratio 10 to 25000). After the production of the vapor-phase carbon fiber, heat treatment at 2000 ° C. or higher can further increase the crystallinity and increase the conductivity. Also in this case, it is effective to add boron or the like which has a function of promoting the degree of graphitization before the heat treatment.

(Preparation of Secondary Battery) A publicly known method can be used to prepare a lithium secondary battery using the carbon material of the present invention.

First of all, in the production of electrodes, a binder (binder) is diluted with a solvent and kneaded with a negative electrode material as usual.
It can be produced by applying it to a current collector (base material).

As the binder, known ones such as fluorine-based polymers such as polyvinylidene fluoride and polytetrafluoroethylene and rubber-based such as SBR (styrene butadiene rubber) can be used. As the solvent, known solvents suitable for the respective binders can be used, such as toluene and N-methylpyrrolidone for fluoropolymers and water for SBR.

The amount of the binder used is 10 for the negative electrode carbon material.
When the amount is 0 parts by mass, 1 to 30 parts by mass is suitable,
Particularly, about 3 to 20 parts by mass is preferable.

The negative electrode material and the binder are kneaded by a ribbon mixer, a screw type kneader, a Spartan Luzer,
Known devices such as a Ledige mixer, a planetary mixer, and a universal mixer can be used.

When applied to the current collector after kneading, it can be carried out by a known method. For example, a method of applying with a doctor blade or a bar coater and then forming with a roll press or the like can be used.

As the current collector, known materials such as copper, aluminum, stainless steel, nickel and alloys thereof can be used.

Known separators can be used, but polyethylene or polypropylene non-woven fabric is particularly preferable.

As the electrolytic solution and electrolyte in the lithium secondary battery of the present invention, known organic electrolytic solutions, inorganic solid electrolytes, and polymer solid electrolytes can be used. From the viewpoint of electrical conductivity, the organic electrolytic solution is preferable.

As the organic electrolytic solution, diethyl ether,
Ethers such as dibutyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, ethylene glycol phenyl ether; formamide, N-methylformamide, N, N-dimethylformamide, N-ethylformamide, N, N-diethylformamide, N-methylacetamide, N, N-dimethylacetamide, N-ethylacetamide, N, N-diethylacetamide, N, N-dimethylpropionamide , Amides such as hexamethylphosphorylamide; dimethyl sulfoxide, sulfur Sulfur-containing compounds such as Holland; methylethylketone, dialkyl ketones such as methyl isobutyl ketone; ethylene oxide, propylene oxide, tetrahydrofuran, 2-methoxy tetrahydrofuran,
Cyclic ethers such as 1,2-dimethoxyethane and 1,3-dioxolane; carbonates such as ethylene carbonate and propylene carbonate; γ-butyrolactone; N-
Methylpyrrolidone; a solution of an organic solvent such as acetonitrile or nitromethane is preferable. Further, preferably ethylene carbonate, butylene carbonate, diethyl carbonate, dimethyl carbonate, propylene carbonate, vinylene carbonate, esters such as γ-butyrolactone, ethers such as dioxolane, diethyl ether, diethoxyethane, dimethyl sulfoxide, acetonitrile, tetrahydrofuran and the like. It is particularly preferable to use a carbonate-based non-aqueous solvent such as ethylene carbonate or propylene carbonate. These solvents may be used alone or in combination of two or more.

A lithium salt is used as the solute (electrolyte) of these solvents. Commonly known lithium salts include LiClO ₄ , LiBF ₄ , LiPF ₆ , and LiAlC.
l ₄ , LiSbF ₆ , LiSCN, LiCl, LiCF ₃
There are SO ₃ , LiCF ₃ CO ₂ , LiN (CF ₃ SO ₂ ) _{2 and the} like.

Examples of the polymer solid electrolyte include polyethylene oxide derivatives and polymers containing the derivatives, polypropylene oxide derivatives and polymers containing the derivatives, phosphoric acid ester polymers, polycarbonate derivatives and polymers containing the derivatives. To be

In the lithium secondary battery using the negative electrode material according to the present invention, a lithium-containing transition metal oxide (chemical formula Li _X MO ₂ , where M is Co, N
By using at least one transition metal selected from i, Mn, and Fe, and X in the range of 0 ≦ X ≦ 1.2), a lithium secondary battery having excellent safety and high rate charge / discharge characteristics can be obtained. . The positive electrode active material may be Li _X CoO ₂ , Li _X NiO ₂ ,
Li _X Mn ₂ O ₄ and those obtained by substituting a part of Co, Ni and Mn thereof with another element such as another transition metal are preferable.

There is no restriction on the selection of members other than those described above, which are necessary for battery construction.

[0042]

The present invention will be described in more detail below by showing typical examples. Note that these are merely examples for description, and the present invention is not limited to these.

Example 1 Carbon fibers were manufactured using the apparatus shown in FIG. In FIG. 1, 1 is a carrier gas heating furnace, 2 is an organic compound evaporator, 3 is a reaction tube, 4 is a collector, and 5 is a transition metal chloride heater. 11, 21, 3
Reference numerals 3 and 51 are heaters for heating the inside of the furnace to a predetermined temperature. Benzene, which is a raw material of carbon fiber, and hydrogen gas, which is supplied to improve the heat transfer by evaporation, are introduced into the inlet 22.
Sent in. Hydrogen as a carrier gas was fed through the hydrogen gas feed port 12. Further, ferric chloride was used as the transition metal chloride 53 as a catalyst raw material, which was filled in the transition metal chloride heater 5 and heated by the heater 51, and argon gas was supplied from the inlet 52. The ferric chloride evaporated here was instantaneously mixed with the raw material benzene and hydrogen gas by the line mixer 6, and was supplied to the reaction tube 3 via the expansion tube 32 and the rectifying plate 31. The carbon fiber 42 produced in the reaction tube 3 entered the collector 4 and was collected by the filter 41. The carrier gas was discharged from the gas discharge port 43.

The operating conditions and results are as follows. (1) Carrier gas heating furnace Temperature 300 ~ 1200 ℃ Hydrogen gas feed rate 150 NL / min (2) Organic compound heating furnace Types of organic compounds Benzene Temperature 200 ~ 300 ℃ Organic compound delivery rate 10g / min (3) Transition metal chloride heater Heating temperature 250-280 ℃ Operating pressure 0.15-0.25MPa Types of transition metal chlorides Ferric chloride Ferric chloride supply rate 0.6g / min Argon gas supply rate 1-2 NL / min (4) Reaction conditions Reaction temperature 1000-1300 ° C Reaction time 0.5-10 sec (5) Result Carbon fiber yield 0.92 g / min (yield * 10%) Shape of carbon fiber Thickness 0.01μm, Length 10μm (* Yield is based on carbon in benzene)

(Example 2) The reactor used was a silicon carbide sintered body having an inner diameter of 90 mm and a length of 260 mm. The raw material liquid was prepared by dissolving 20 g of ferric chloride in 20 g of ethanol to prepare solution 1, dissolving 2 g of sulfur in 2000 g of benzene to prepare solution 2, and mixing solution 1 and solution 2. The prepared raw material liquid was held in a raw material container. The ratio of ferric chloride in the raw material liquid was 0.9% by mass, and the ratio of sulfur was 0.1% by mass. Nitrogen gas was circulated in the system and oxygen gas was driven out, then hydrogen gas was circulated and the system was replaced with a hydrogen gas atmosphere. Then, start to raise the temperature of the reactor 1
The temperature was raised to 200 ° C.

The raw material liquid was supplied to the vaporizer at a flow rate of 10 g / min by a pump to vaporize the entire amount and hydrogen gas at 20 L / min.
Was mixed with 60 L / min of hydrogen gas which was transported to the reactor and heated to 400 ° C. immediately before the reactor, and was supplied to the reactor. In this state, reaction was carried out for 3 hours to obtain carbon fibers.

When the produced carbon fiber was observed with an electron microscope, the average fiber diameter was 21 nm. When the mass was measured, the carbonization recovery rate (= mass of carbon fiber obtained / mass of benzene supplied) was 3%. 1 carbon fiber
After heat treatment (calcination) at 000 ° C., the iron content in the obtained fiber was 3.2 mass%.

Example 3 The reactor used was an alumina sintered body having an inner diameter of 90 mm and a length of 260 mm. The raw material liquid was prepared by dissolving 26 g of ferrous chloride in 20 g of ethanol to prepare solution 1, dissolving 2 g of sulfur in 2000 g of benzene to prepare solution 2, and mixing solution 1 and solution 2. The prepared raw material liquid was held in a raw material container. The ratio of ferrous chloride in the raw material liquid was 1.3% by mass, and the ratio of sulfur was 0.1% by mass. Nitrogen gas was circulated in the system and oxygen gas was driven out, then hydrogen gas was circulated and the system was replaced with a hydrogen gas atmosphere. Then, start to raise the temperature of the reactor 1
The temperature was raised to 200 ° C.

The raw material liquid was conveyed by a pump at a flow rate of 10 g / min, and hydrogen gas 60 heated to 400 ° C. immediately before the reactor was used.
It was mixed with L / min and fed to the reactor. 3 in this state
After reacting for a time, carbon fibers were obtained. When the produced carbon fiber was observed with an electron microscope, the average fiber diameter was 40 nm. When the mass was measured, the carbonization recovery rate (= mass of carbon fiber obtained / mass of benzene supplied) was 4%. After heat treating (calcining) the carbon fiber at 1000 ° C,
The iron content in the obtained fiber was 3.0% by mass.

Example 4 The reactor used was an alumina sintered body having an inner diameter of 90 mm and a length of 260 mm. The raw material liquid was prepared by dissolving 2 g of sulfur in 2000 g of benzene. The prepared raw material liquid was held in a raw material container.
The proportion of sulfur in the raw material liquid was 0.1% by mass.

Nitrogen gas was circulated in the system to expel oxygen gas, and then hydrogen gas was circulated to replace the atmosphere in the system with a hydrogen gas atmosphere. Then, the temperature of the reactor was started to be raised to 1200 ° C.

The raw material liquid was supplied to the vaporizer at a flow rate of 10 g / min by a pump, and the entire amount was vaporized to obtain hydrogen gas of 20 L / min.
Was mixed with 60 L / min of hydrogen gas which was transported to the reactor and heated to 400 ° C. immediately before the reactor, and was supplied to the reactor. Moreover, 500 g of ferric chloride is placed in the vaporizer, and the temperature is 300 ° C.
The generated steam was conveyed to hydrogen gas of 1 L / min and supplied to the reactor.

In this state, reaction was carried out for 3 hours to obtain carbon fibers. When observing the produced carbon fiber with an electron microscope,
The average fiber diameter was 22 nm. When the mass was measured,
The carbonization recovery rate (= mass of carbon fiber obtained / mass of benzene supplied) was 2%. After heat treating (calcining) the carbon fiber at 1000 ° C., the iron content in the obtained fiber was 2.5 mass%.

Reference Example 1 The reactor used was a silicon carbide sintered body having an inner diameter of 90 mm and a length of 260 mm.

The raw material liquid was prepared by dissolving 2 g of sulfur in 23 g of ferrocene and 2000 g of benzene. The prepared raw material liquid was held in a raw material container. The ratio of ferrocene in the raw material liquid is 1.1% by mass, and the ratio of sulfur is 0.1.
It was mass%. Nitrogen gas was circulated in the system and oxygen gas was driven out, then hydrogen gas was circulated and the system was replaced with a hydrogen gas atmosphere. After that, the temperature rise of the reactor is started and 1200
The temperature was raised to ° C.

The raw material liquid was supplied to the vaporizer at a flow rate of 10 g / min by a pump to vaporize the entire amount and hydrogen gas at 20 L / min.
Was mixed with 60 L / min of hydrogen gas which was transported to the reactor and heated to 400 ° C. immediately before the reactor, and was supplied to the reactor. In this state, the reaction was carried out for 3 hours to obtain a black powder.

When the black powder produced was observed with an electron microscope, it was found that there were few fibers and most of the particles. Although the same concentration of iron as in Example 2 was supplied, it was found that the type of catalyst compound affects the fiber formation.

Comparative Example 1 The reactor used was a silicon carbide sintered body having an inner diameter of 90 mm and a length of 260 mm. The raw material liquid was prepared by dissolving 49 g of Fe ₂ (SO ₄ ) ₃ and 2 g of sulfur in 2000 g of benzene. The prepared raw material liquid was held in a raw material container. Fe ₂ (SO ₄ ) ₃ in the raw material liquid
Was 2.4 mass%, and the proportion of sulfur was 0.1 mass%. Nitrogen gas was circulated in the system and oxygen gas was driven out, then hydrogen gas was circulated and the system was replaced with a hydrogen gas atmosphere. Then, the temperature of the reactor was started to be raised to 1200 ° C.

The raw material liquid was supplied to the vaporizer at a flow rate of 10 g / min by a pump to vaporize the entire amount and hydrogen gas at 20 L / min.
Was mixed with 60 L / min of hydrogen gas which was transported to the reactor and heated to 400 ° C. immediately before the reactor, and was supplied to the reactor. In this state, the reaction was carried out for 3 hours to obtain a black powder.

When the produced black powder was observed with an electron microscope, it was found that there were few fibers and most of the particles.

Although iron was supplied at the same concentration as in Example 2, it was found that the type of catalyst compound affects the formation of fibers.

[0062]

EFFECTS OF THE INVENTION According to the production method of the present invention, vapor-grown carbon fibers having a fine and uniform diameter can be obtained, and can be obtained at a lower cost than ferrocene, which is an organic transition metal compound that has been conventionally used. It has become possible to use readily inorganic transition metal chlorides such as ferric chloride as a catalyst source.

Further, according to the production method of the present invention, carbon fibers can be produced with high productivity with a small amount of added catalyst.

The carbon fiber of the present invention has a low content of transition metal used as a catalyst, such as iron, and is suitable for resin compositions and electrode materials for secondary batteries.

[0065]

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an apparatus used for carrying out a manufacturing method of the present invention.

[Explanation of symbols]

1 Carrier gas heating furnace 2 raw material containers 3 reactor 4 collector 5 Transition metal chloride heater 6 line mixer 11, 21, 33, 51 heater 12, 22, 52 gas inlet 31 Current plate 32 Expansion tube 41 Filter 42 carbon fiber 43 gas outlet

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kotaro Yano             Showa 5-1 Okawa-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa             Denko Research and Development Center F-term (reference) 4G146 AA01 AB06 AC03A AC03B                       AD37 BA12 BC08 BC43 BC44                 4L037 CS03 FA02 PA09 PA13 UA04

Claims (14)

[Claims] 1. A method for producing a vapor-grown carbon fiber by a thermal decomposition reaction of an organic compound and an inorganic transition metal compound as main raw materials, wherein a transition metal chloride is used as the inorganic transition metal compound, and Transition metal chloride is used in an amount of 0.01 to 20% by mass. 2. A transition metal chloride is dissolved in an organic compound,
The method for producing a vapor grown carbon fiber according to claim 1, further comprising a step of obtaining a mixed gas of these by evaporating the mixed gas and a step of mixing a carrier gas and supplying the mixed gas to a carbon fiber production zone. 3. The gas according to claim 1, comprising a step of obtaining a mixed gas of a carrier gas and a vaporized gas of an organic compound, and then a step of mixing the vaporized gas of a transition metal chloride and supplying the mixed gas to a carbon fiber production zone. Method for producing phase-grown carbon fiber. 4. A step of producing transition metal chloride fine particles by spraying a transition metal chloride solution, a step of obtaining a mixed gas of a carrier gas and a vaporized gas of an organic compound, the transition metal chloride fine particles and a carrier. The method for producing a vapor-grown carbon fiber according to claim 1, comprising a step of supplying a gas and a vaporized gas of an organic compound to the carbon fiber production zone. 5. The transition metal chloride is at least one kind of transition metal chloride selected from the group consisting of iron, nickel, cobalt, molybdenum and vanadium, according to any one of claims 1 to 4. A method for producing a vapor-grown carbon fiber as described above. 6. The transition metal chloride is at least one selected from the group consisting of iron chloride, nickel chloride and cobalt chloride.
The method for producing a vapor-grown carbon fiber according to claim 5, which is a seed. 7. The method for producing a vapor grown carbon fiber according to claim 1, wherein the organic compound is an aromatic compound, acetylene, ethylene, butadiene, or a mixture thereof. 8. The aromatic compound is benzene, toluene,
The method for producing a vapor-grown carbon fiber according to claim 7, which is xylene or naphthalene. 9. A transition metal chloride is dissolved in an organic compound,
The method for producing a vapor-grown carbon fiber according to claim 2, wherein methanol, ethanol, or acetone is added as a dissolution aid in the step of obtaining the mixed gas by evaporating the mixed gas. 10. A vapor grown carbon fiber produced by the production method according to any one of claims 1 to 9. 11. The vapor grown carbon fiber according to claim 10, wherein the fiber outer diameter is 1 to 500 nm and the fiber length is 0.5 to 100 μm. 12. The vapor grown carbon fiber produced by the production method according to claim 1, wherein the transition metal chloride is iron chloride, the fiber outer diameter is 1 to 500 nm, and the fiber length is 0.5 to. 1
A vapor grown carbon fiber having a diameter of 00 μm and an iron content in the fiber of 5% by mass or less. 13. A resin composition containing a vapor grown carbon fiber according to claim 10 in a resin. 14. A secondary battery using the electrode material containing the vapor grown carbon fiber according to claim 10. Description: