JP2011148680A - Carbon microparticle and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a carbon microparticle that has a high quality as a carbon microparticle, a narrow particle size distribution and a high degree of graphitization, and the carbon microparticle. <P>SOLUTION: The method for obtaining the carbon microparticle comprises carbonizing and firing a polyamideimide microparticle used as a starting material. The method for manufacturing the carbon microparticle comprises: mixing the polyamideimide and a polymer that is different from the polyamideimide in an organic solvent; forming an emulsion in a system wherein phase separation occurs between a solution phase essentially comprising the polyamideimide and a solution phase essentially comprising the other polymer; contacting the emulsion with a poor solvent for the polyamideimide, thereby causing the polyamideimide to precipitate and producing a polyamideimide microparticle; and carbonizing and firing the polyamideimide microparticle. The carbon microparticle manufactured thereby is also provided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fine carbon particle and a method for producing the same.

  Carbon fine particles have excellent mechanical properties, chemical resistance, heat resistance, wear resistance, and electrical conductivity, so heat resistant fillers, composite material reinforcements, fillers, automotive parts, electrical parts, industrial machinery, office work It is used in a wide range of equipment and applications, and in the future, high-quality and highly practical carbon particles are required for further enhancement of functionality.

  Conventionally, a method for producing fine carbon particles has disclosed a method in which coke, pitch, and the like as raw materials are fired and then mechanically pulverized, and a method in which synthetic resin fine particles are prepared and then fired.

  Although the degree of graphitization of coke and pitch-fired carbon materials is high, the fine particle size is reduced by mechanical pulverization, resulting in a wide particle size distribution of the resulting carbon fine particles and non-spherical particle shape. When used, there are problems such as inferior dispersibility and filling properties in the resin.

  As a method of firing synthetic resin fine particles to produce carbon fine particles, a method of firing phenol / formaldehyde resin fine particles or polyacrylonitrile fine particles is disclosed. In the case of the production method in which the phenol / formaldehyde resin fine particles are fired, the phenol / formaldehyde fine particles obtained by polycondensation of phenol and formaldehyde as raw materials are insufficient in quality. In addition, since the particle size distribution is wide, the obtained carbon fine particles also have a wide particle size distribution accordingly (Patent Document 1). On the other hand, when carbon fine particles are produced from polyacrylonitrile-based polymer fine particles, since the fine particles are produced by polymerization, water-based polymerization with a high copolymerization ratio of polyacrylonitrile is likely to aggregate and difficult to control the reaction. It was insufficient in terms of sex. Further, it is disclosed that the particle size distribution becomes wide and it is difficult to obtain true spherical fine particles (Patent Documents 2 and 3). Although a method for producing carbon fine particles having a narrow particle size distribution by using a special polymerization method is also disclosed, fine particles of a copolymer obtained by copolymerizing a copolymer component such as divinylbenzene and styrene with acrylonitrile are used. For this reason, there is a problem that the quality is not sufficient and sufficient characteristics cannot be obtained (Patent Documents 4 and 5). That is, in the conventional method, it is difficult to produce practical carbon fine particles with an industrially simple method and with good quality.

JP-A 63-129006 JP 2003-226720 A JP 61-26505 A Japanese Patent Laid-Open No. 05-139711 International Publication No. 2005/098998

  An object of the present invention is to provide a method for producing high-quality carbon fine particles. In a more preferred embodiment, an object is to provide a simple method for producing carbon fine particles having a narrow particle size distribution and a high degree of graphitization.

  As a result of intensive studies, the present inventors have found that the above object can be achieved by carbonizing and firing the polyamideimide fine particles.

That is, the present invention has the following configuration.
[1] A method for producing carbon fine particles, comprising carbonizing and firing polyamideimide fine particles,
[2] In a system in which a polyamideimide and a polymer different from polyamideimide are mixed in an organic solvent and phase-separated into a solution phase mainly composed of polyamideimide and a solution phase mainly composed of a different polymer. The carbon fine particles according to [1], wherein the polyamideimide fine particles are obtained by depositing the polyamideimide by contacting with a poor solvent of the polyamideimide to form a polyamideimide fine particles. Method,
[3] The method for producing carbon fine particles according to any one of [1] to [2], wherein the number average particle diameter of the carbon fine particles is 0.1 to 100 μm,
[4] The method for producing carbon fine particles according to any one of [1] to [3], wherein the particle size distribution index of the carbon fine particles is 1.0 to 2.0.
[5] The method for producing carbon fine particles according to any one of [1] to [4], wherein the sphericity of the carbon fine particles is 80 or more,
[6] The method for producing carbon fine particles according to any one of [1] to [5], wherein the degree of graphitization of the carbon fine particles is 1.0 or more,
[7] Carbon fine particles obtained by the production method according to any one of [1] to [6],
[8] Carbon having a number average particle size of 0.1 to 100 μm, a particle size distribution index of 1.0 to 2.0, a sphericity of 80 or more, and a graphitization degree of 1.0 or more. Fine particles.

  According to the present invention, it is possible to obtain carbon fine particles having good quality and excellent practicality. In a more preferred embodiment, carbon fine particles having a narrow particle size distribution and a high degree of graphitization can be obtained.

  The fine carbon particles obtained by the present invention have good quality, and in a preferred embodiment, since the particle size distribution is narrower, the carbon fine particles exhibit high dispersibility and filling properties in resins and rubbers, and further have a high degree of graphitization. , Resin modifiers, conductive rubber, anisotropically conductive particles, chromatography carriers, molecular adsorbents, toners, negative electrode materials for lithium ion batteries, catalyst carriers, activated carbon, capacitor electrodes, and the like.

FIG. 1 is a scanning electron micrograph of polyamideimide fine particles obtained in Production Example 1. FIG. 2 is a scanning electron micrograph of carbon fine particles obtained by carbonizing and firing the polyamideimide fine particles obtained in Example 1.

  The present invention will be described in more detail below.

  The carbon fine particles of the present invention are fine particles consisting essentially of carbon, and the method for producing carbon fine particles of the present invention is a method for producing carbon fine particles characterized by carbonizing and firing polyamideimide fine particles.

  The present invention is characterized in that polyamideimide fine particles are used as a raw material and carbonized and fired. Although the details of the reason why high-quality carbon fine particles can be obtained by using polyimide fine particles have not been fully elucidated, the fact that the polymer chain has a cyclic imide structure and an amide structure is carbonized and cyclized during carbonization firing. Since it has an easy structure, it is presumed that high-quality carbon fine particles can be obtained. Therefore, in the present invention, polyamideimide fine particles are used as a raw material.

  Furthermore, in the present invention, from the viewpoint of obtaining carbon fine particles having a narrow particle size distribution, it is preferable to use polyamideimide fine particles having a narrow particle size distribution as a raw material.

  The polyamideimide constituting the polyamideimide fine particles is a polymer having an imide bond and an amide bond in the polymer main chain skeleton, and includes a polymer having a structure represented by the general formula (1).

(Wherein R ₁ and R ₂ each independently represent an aromatic or aliphatic hydrocarbon group, and have a structural group having an ether bond, a thioether bond, a carboquinyl group, a halogen bond, or an amide bond inside. May be.)

The polyamide-imide preferably contains an aromatic hydrocarbon group in the main chain, and the above R ₁ and R ₂ are aromatic hydrocarbon groups, so that higher quality carbon fine particles can be obtained. This is preferable.

  Specifically, a copolymer of trimellitic anhydride and phenylenediamine or a derivative thereof, a copolymer of trimellitic anhydride and 4,4′-diaminobiphenyl or a derivative thereof, trimellitic anhydride or a derivative thereof Copolymer of o-tolidine, copolymer of trimellitic anhydride and 4,4'-diaminodiphenyl ether or its derivative, copolymer of trimellitic anhydride and 4,4'-methylenedianiline or its derivative Copolymers, copolymers of trimellitic anhydride and 4,4'-isopropylidenedianiline or derivatives thereof, copolymers of trimellitic anhydride and hexamethylenediamine or derivatives thereof, trimellitic anhydride and pentamethylenediamine Or a copolymer thereof, trimellitic anhydride and 4,4′-diaminodicyclohexyl Such styrene or copolymers of derivatives thereof.

  As a copolymer here, the halogen group, a C1-C4 hydrocarbon group, etc. may be contained as a substituent in the structure.

  The weight average molecular weight of the polyamideimide in the present invention is 1,000 to 100,000,000, preferably 1,000 to 10,000,000, more preferably 5,000 to 1,000,000, particularly preferably. Is in the range of 10,000 to 500,000, most preferably 10,000 to 100,000.

  The weight average molecular weight here refers to a weight average molecular weight measured by gel permeation chromatography (GPC) using dimethylformamide as a solvent and converted to polystyrene.

  When the measurement cannot be performed with dimethylformamide, the measurement is performed using hexafluoroisopropanol.

  The number average particle diameter of the polyamideimide fine particles used in the present invention is usually 100 μm or less as an upper limit, preferably 50 μm or less, and more preferably 30 μm or less. Moreover, as a minimum, it is 0.1 micrometer or more, More preferably, it is 0.5 micrometer or more, More preferably, it is 0.7 micrometer or more, Most preferably, it is 1 micrometer or more.

  If the number average particle diameter is too small, the handleability deteriorates, and if it is too large, the resulting carbon fine particles are increased, and the dispersibility as a filler is lowered, which is not preferable.

  The number average particle diameter is calculated from the following formula (1) by observing 100 arbitrary particles in a scanning electron micrograph, measuring the diameter. When the particle is not a perfect circle, the major axis is measured.

  In the present invention, in order to obtain carbon fine particles having a narrow particle size distribution, it is preferable to narrow the particle size distribution of the polyamideimide fine particles.

  The particle size distribution of the polyamideimide fine particles can be represented by a particle size distribution index, and is in the range of 1.0 to 2.0, preferably 1.0 to 1.8, more preferably 1.0 to 2.0. 1.5, particularly preferably 1.0 to 1.3. A particle size distribution index within this range is preferable because carbon fine particles having a narrow particle size distribution can be obtained. The particle size distribution index is calculated from the ratio of the volume average particle size to the number average particle size according to the following formula (3). The volume average particle diameter is calculated from the following formula (2) by observing 100 arbitrary particles in a scanning electron micrograph, measuring the diameter. When the particle is not a perfect circle, the major axis is measured.

  Ri: particle diameter of each particle, n: number of measurement 100, Dn: number average particle diameter, Dv: volume average particle diameter, PDI: particle diameter distribution index.

  The sphericity of the polyamideimide used in the present invention is preferably 80 or more, more preferably 85 or more, still more preferably 90 or more, and most preferably 95 or more. When the sphericity is within the above range, it is preferable because true spherical carbon fine particles can be obtained. The sphericity is calculated according to the formula (4) from the average of 30 arbitrary particles by observing the particles with a scanning electron microscope, measuring the short diameter and the long diameter.

  Note that n is 30 measurements.

  Next, the method for producing carbon fine particles of the present invention will be described.

  The polyamideimide fine particles used as a raw material in the present invention can be obtained by applying a conventionally known fine particle resin fine particle technique. For example, as a batch type fine particle method, a polymerization precipitation method, an emulsion solidification method, or the like. Examples thereof include a submerged drying method and a continuous micronization method such as a forced melt kneading method and an emulsion method using a microchannel.

  Among them, as a preferable method in that the quality of the carbon fine particles after carbonization is further improved and polyamideimide fine particles having a narrow particle size distribution can be obtained, the polyamideimide to be microparticulated and a different type that dissolves in the poor solvent of the polyamideimide are preferred. A polymer phase (hereinafter sometimes referred to as a heterogeneous polymer) and an organic solvent are dissolved and mixed, and a solution phase containing polyamideimide as a main component (hereinafter also referred to as a polyamideimide solution phase), and a heterogeneous polymer as a main component. In a system that phase-separates into two phases of a solution phase (hereinafter also referred to as a different polymer solution phase), after forming an emulsion, polyamideimide fine particles are precipitated by contacting with a poor solvent of polyamideimide Such a method is mentioned.

  Polyamideimide microparticles made by this method not only have a narrow particle size distribution, but the folded state of the polymer chain inside the microparticles becomes a thermodynamically stable orientation, so the cyclization reaction during carbonization proceeds. It is considered that the cyclization reaction is likely to occur due to the easy arrangement, and the degree of graphitization is likely to be improved.

  The above method will be described more specifically.

  In the above, “polyamideimide, a different polymer that dissolves in a poor solvent of the polyamideimide, and an organic solvent are dissolved and mixed, so that the solution phase is mainly composed of polyamideimide and the solution phase is composed mainly of a different polymer. The term “phase-separating system” refers to a system that, when mixed with polyamideimide, a different polymer, and an organic solvent, is divided into two phases: a solution phase mainly containing polyamideimide and a solution phase mainly containing different polymer.

  By using such a phase-separating system and mixing under the phase-separating conditions, an emulsified state can be obtained and an emulsion can be formed.

  In the above, whether the polyamideimide and the different polymer are dissolved or not is determined with respect to the organic solvent at the temperature at which this method is carried out, that is, the temperature at which the polyamideimide and the different polymer are dissolved and mixed and separated into two phases. It discriminate | determines by whether it melt | dissolves exceeding 1 mass%.

  This emulsion has a polyamideimide solution phase as a dispersed phase and a heterogeneous polymer solution phase as a continuous phase, and the polyamideimide solution phase in the emulsion is brought into contact with the emulsion by contacting the polyamideimide with a poor solvent. Imide precipitates, and polyamideimide fine particles can be obtained.

  The heterogeneous polymer is a heterogeneous polymer different from the polyamideimide, and includes a thermoplastic resin and a thermosetting resin, but is soluble in an organic solvent that dissolves the polyamideimide used in this method and a poor solvent of the polyamideimide. Among these, those that dissolve in the above-mentioned organic solvents and dissolve in alcohol solvents or water are more preferable in terms of industrial handling, and further dissolve in organic solvents and dissolve in methanol, ethanol, or water. Those are particularly preferred.

  To specifically illustrate different types of polymers, poly (vinyl alcohol) (which may be fully saponified or partially saponified poly (vinyl alcohol)), poly (vinyl alcohol-ethylene) copolymer ( Fully saponified or partially saponified poly (vinyl alcohol-ethylene) copolymer), polyvinylpyrrolidone, poly (ethylene glycol), sucrose fatty acid ester, poly (oxyethylene fatty acid ester), poly (Oxyethylene laurin fatty acid ester), poly (oxyethylene glycol monofatty acid ester), poly (oxyethylene alkylphenyl ether), poly (oxyalkyl ether), polyacrylic acid, sodium polyacrylate, polymethacrylic acid, polymethacrylic acid Sodium, polystyrene sulfonic acid, poly Sodium restyrenesulfonate, polyvinylpyrrolidinium chloride, poly (styrene-maleic acid) copolymer, aminopoly (acrylamide), poly (paravinylphenol), polyallylamine, polyvinyl ether, polyvinyl formal, poly (acrylamide), poly (Methacrylamide), poly (oxyethyleneamine), poly (vinylpyrrolidone), poly (vinylpyridine), polyaminosulfone, polyethyleneimine and other synthetic resins, disaccharides such as maltose, cellobiose, lactose, sucrose, cellulose, chitosan, Hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, ethyl cellulose, ethyl hydroxy cellulose, carboxymethyl ethyl cellulose, carboxymethyl cell Lose, cellulose derivatives such as sodium carboxymethyl cellulose, cellulose ester, amylose and derivatives thereof, starch and derivatives thereof, polysaccharides or derivatives thereof such as dextrin, cyclodextrin, sodium alginate and derivatives thereof, gelatin, casein, collagen, albumin, fibroin , Keratin, fibrin, carrageenan, chondroitin sulfate, gum arabic, agar, protein, etc., and preferably poly (vinyl alcohol) (fully saponified or partially saponified poly (vinyl alcohol)) ), Poly (vinyl alcohol-ethylene) copolymer (may be fully saponified or partially saponified poly (vinyl alcohol-ethylene) copolymer), polyethylene glycol, sucrose fat Acid ester, poly (oxyethylene alkylphenyl ether), poly (oxyalkyl ether), poly (acrylic acid), poly (methacrylic acid), carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, methylcellulose, ethylcellulose, ethylhydroxycellulose, carboxy Cellulose derivatives such as methyl ethyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, cellulose ester, and polyvinyl pyrrolidone, and more preferably poly (vinyl alcohol) (fully saponified or partially saponified poly (vinyl alcohol) Good), poly (vinyl alcohol-ethylene) copolymer (fully saponified or partially saponified poly (vinyl alcohol-ethylene) Copolymer), polyethylene glycol, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, ethyl cellulose, ethyl hydroxy cellulose, carboxymethyl ethyl cellulose, carboxymethyl cellulose, carboxymethyl cellulose sodium, cellulose ester and other cellulose derivatives, especially polyvinylpyrrolidone, Preferably, poly (vinyl alcohol) (which may be fully saponified or partially saponified poly (vinyl alcohol)), poly (ethylene glycol), carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, methylcellulose, ethylcellulose, Cellulose derivatives such as ethyl hydroxycellulose, Vinylpyrrolidone.

  The molecular weight of the heterogeneous polymer is preferably a weight average molecular weight of 1,000 to 100,000,000, more preferably 1,000 to 10,000,000, and still more preferably 5,000 to 1,000,000. 000, particularly preferably in the range of 10,000 to 500,000, and most preferably in the range of 10,000 to 100,000.

  The weight average molecular weight here refers to a weight average molecular weight measured by gel permeation chromatography (GPC) using water as a solvent and converted into polyethylene glycol.

  Use dimethylformamide when it cannot be measured with water, use tetrahydrofuran when it cannot be measured with water, and use hexafluoroisopropanol when it cannot be measured with water.

  The organic solvent for dissolving the polyamideimide and the different polymer is an organic solvent capable of dissolving the polyamideimide and the different polymer to be used, and is selected according to the type of each polymer.

  Specific examples include aromatic hydrocarbon solvents such as benzene, toluene, xylene and 2-methylnaphthalene, ester solvents such as ethyl acetate, methyl acetate, butyl acetate, butyl propionate and butyl butyrate, chloroform, bromoform, and chloride. Halogenated hydrocarbon solvents such as methylene, carbon tetrachloride, 1,2-dichloroethane, 1,1,1-trichloroethane, chlorobenzene, 2,6-dichlorotoluene, hexafluoroisopropanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl Ketone solvents such as butyl ketone, alcohol solvents such as methanol, ethanol, 1-propanol, 2-propanol, N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF) Aprotic polar solvents such as N, N-dimethylacetamide (DMA), propylene carbonate, trimethyl phosphoric acid, 1,3-dimethyl-2-imidazolidinone, sulfolane, formic acid, acetic acid, propionic acid, butyric acid, lactic acid, etc. Carboxylic acid solvents, anisole, diethyl ether, tetrahydrofuran, diisopropyl ether, dioxane, diglyme, dimethoxyethane, and other ether solvents, 1-butyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium hydrogen sulfate Ionic liquids such as 1-ethyl-3-imidazolium acetate, 1-ethyl-3-methylimidazolium thiocyanate, or a mixture thereof. Preferred are aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, halogenated hydrocarbon solvents, alcohol solvents, ether solvents, aprotic polar solvents, carboxylic acid solvents, and more preferred are: Alcohol solvents that are water-soluble solvents, aprotic polar solvents, and carboxylic acid solvents are preferred, and aprotic polar solvents and carboxylic acid solvents are particularly preferred, and are readily available and have a wide range of polyamideimides. Most preferably, N-methyl-2-pyrrolidone, dimethyl sulfoxide, N, and the like can be dissolved, and can be uniformly mixed with a solvent that can be preferably used as a poor solvent described later, such as water and alcohol solvents. , N-dimethylformamide, N, N-dimethylacetamide, propylene carbonate, formic acid and acetic acid.

  These organic solvents may be used in a plurality of types, or may be used in combination. However, particles having a relatively small particle size and a small particle size distribution can be obtained, and when used solvents are recycled. From the viewpoint of avoiding the troublesome separation process, reducing the manufacturing process load, it is preferable to use a single organic solvent, and it should be a single organic solvent that dissolves both polyamideimide and different polymers. Is preferred.

  The poor solvent for polyamideimide in this method refers to a solvent that does not dissolve polyamideimide. When the solvent is not dissolved, the solubility of the polyamideimide in the poor solvent is 1% by mass or less, more preferably 0.5% by mass or less, and further preferably 0.1% by mass or less.

  In this method, a poor solvent for polyamideimide is used, and the poor solvent is preferably a poor solvent for polyamideimide and a solvent that dissolves a different polymer. Thereby, polyamideimide fine particles can be efficiently precipitated. Moreover, it is preferable that the solvent for dissolving the polyamideimide and the different polymer and the poor solvent for the polyamideimide are uniformly mixed.

  The poor solvent in this method varies depending on the type of polyamideimide used, desirably the type of polyamideimide used, and both types of different polymers, but specific examples include benzene, toluene, xylene, 2-methylnaphthalene. Aromatic hydrocarbon solvents such as ethyl acetate, methyl acetate, butyl acetate, butyl propionate, butyl butyrate and the like, chloroform, bromoform, methylene chloride, carbon tetrachloride, 1,2-dichloroethane, 1,1 , 1-trichloroethane, chlorobenzene, 2,6-dichlorotoluene, halogenated hydrocarbon solvents such as hexafluoroisopropanol, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl butyl ketone, methanol, ethanol, 1-propanol Alcohol solvents such as 2-propanol, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, trimethyl phosphoric acid, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone , Aprotic polar solvents such as sulfolane, carboxylic acid solvents such as formic acid, acetic acid, propionic acid, butyric acid and lactic acid, ether solvents such as anisole, diethyl ether, tetrahydrofuran, diisopropyl ether, dioxane, diglyme and dimethoxyethane, water Examples include a solvent selected from at least one of them.

  From the viewpoint of efficiently granulating polyamideimide, an aromatic hydrocarbon solvent, an aliphatic hydrocarbon solvent, an alcohol solvent, an ether solvent, and water are preferable, and an alcohol solvent, water is most preferable. Particularly preferred is water.

  In this method, polyamideimide fine particles can be obtained by efficiently precipitating polyamideimide by appropriately selecting and combining polyamideimide, a different polymer, an organic solvent for dissolving them, and a poor solvent for polyamideimide. In this case, the solution obtained by mixing and dissolving the polyamideimide, the different polymer, and the organic solvent for dissolving them is phase-separated into two phases, a solution phase mainly composed of polyamideimide and a solution phase mainly composed of the different polymer. It is necessary to.

  The conditions for generating the state of two-phase separation are as follows: polyamideimide, type of different polymer B, polyamideimide, molecular weight of different polymer, type of organic solvent, polyamideimide, concentration of different polymer, temperature at which this method is carried out, It depends on the pressure.

  In order to obtain conditions that are likely to result in a phase separation state, it is preferable that the difference in solubility parameter (hereinafter also referred to as SP value) between the polyamideimide and the different polymer is separated.

At this time, the difference in SP value is 1 (J / cm ³ ) ^1/2 or more, more preferably 2 (J / cm ³ ) ^1/2 or more, and further preferably 3 (J / cm ³ ) ^1/2 or more. Particularly preferably, it is 5 (J / cm ³ ) ^1/2 or more, and very preferably 8 (J / cm ³ ) ^1/2 or more. When the SP value is within this range, phase separation is easily performed.

There is no particular limitation as long as both the polyamideimide and the heterogeneous polymer are dissolved in an organic solvent and phase-separated into two phases, but the upper limit of the difference in SP value is preferably 20 (J / cm ³ ) ^1/2 or less, More preferably, it is 15 (J / cm ³ ) ^1/2 or less, and further preferably 10 (J / cm ³ ) ^1/2 or less.

  Here, the SP value is calculated based on the Fedor's estimation method, and is calculated based on the cohesive energy density and the molar molecular volume (hereinafter also referred to as a calculation method). ("SP Value Basics / Applications and Calculation Methods" by Hideki Yamamoto, Information Organization Co., Ltd., published on March 31, 2005).

  When the calculation cannot be performed by this estimation method, the SP value is calculated by an experimental method by determining whether or not the solubility parameter is dissolved in a known solvent (hereinafter also referred to as an experimental method). ("Polymer Handbook Fourth Edition" by J. Brand, published in Wiley 1998).

  In order to select the conditions for the phase separation state, a three-component phase diagram can be prepared by a simple preliminary experiment by observing the ratio of the three components of polyamidoimide, a heterogeneous polymer and an organic solvent for dissolving them. Can be distinguished.

  The phase diagram is prepared by mixing and dissolving the polyamideimide, the heterogeneous polymer and the solvent at an arbitrary ratio, and determining whether an interface is formed when left standing, preferably at least 3 points, preferably 5 points or more, More preferably, it is carried out at 10 or more points, and by separating the region that separates into two phases and the region that becomes one phase, the conditions for achieving the phase separation state can be determined.

  At this time, in order to determine whether or not the phase is separated, the polyamideimide and the different polymer are adjusted to a ratio of the desired polyamideimide, different polymer and solvent at the temperature and pressure at which the present invention is to be carried out. Thereafter, the polyamideimide and the different polymer are completely dissolved, and after dissolving, the mixture is sufficiently stirred and left for 3 days to confirm whether or not the phase separation is macroscopically performed.

  However, in the case of a sufficiently stable emulsion, macroscopic phase separation may not occur even after standing for 3 days. In this case, phase separation is determined by using an optical microscope, a phase contrast microscope, or the like based on whether the phase is microscopically separated.

  The phase separation is formed by separating a polyamideimide solution phase mainly composed of polyamideimide and a heterogeneous polymer solution phase mainly composed of a different polymer in an organic solvent. In this case, the polyamideimide solution phase is a phase in which polyamideimide is mainly distributed, and the different polymer solution phase is a phase in which different polymers are mainly distributed. At this time, the polyamideimide solution phase and the different polymer solution phase seem to have a volume ratio according to the type and amount of polyamideimide and different polymer used.

  As a concentration at which phase separation can be obtained and industrially feasible, it is assumed that the concentration of the polyamidoimide and the heterogeneous polymer in the organic solvent is within the possible range of dissolution in the organic solvent. Preferably, it is more than 1% by mass to 50% by mass, more preferably more than 1% by mass to 30% by mass, and still more preferably 2% by mass to 20% by mass.

  In this method, the interfacial tension between the two phases of the polyamideimide solution phase and the heterogeneous polymer solution phase is an organic solvent, so the interfacial tension is small, and the resulting emulsion can be stably maintained due to its nature. The particle size distribution seems to be smaller. In particular, when the organic solvent of the polyamideimide phase and the different polymer phase are the same, the effect is remarkable.

Since the interfacial tension between the two phases in this method is too small, it cannot be measured directly by the hanging drop method in which a different kind of solution is added to a commonly used solution. The interfacial tension can be estimated by estimating from the surface tension. When the surface tension of each phase with air is r ₁ and r ₂ , the interfacial tension r ₁₂ can be estimated by the absolute value of r ₁₂ = r ₁ −r ₂ . At this time, a preferable range of r ₁₂ is more than 0 to 10 mN / m, more preferably more than 0 to 5 mN / m, still more preferably more than 0 to 3 mN / m, and particularly preferably 0. Super-2 mN / m.

  The viscosity between the two phases in this method affects the average particle size and particle size distribution, and the smaller the viscosity ratio, the smaller the particle size distribution. In the case where the viscosity ratio is defined as a polyamideimide solution phase / different polymer solution phase under a temperature condition where the present invention is to be carried out, a preferable range is 0.1 or more and 10 or less, and a more preferable range is 0. .2 or more, 5 or less, more preferably 0.3 or more and 3 or less, particularly preferable range is 0.5 or more and 1.5 or less, and remarkably preferable range is 0.8 or more and 1.2 or less. It is.

  Polyamideimide fine particles are produced using the phase separation system thus obtained. The atomization is performed in a normal reaction tank. The temperature suitable for carrying out the present invention is in the range of −50 ° C. to 200 ° C., preferably −20 ° C. to 150 ° C., more preferably 0 ° C. to 120 ° C. from the viewpoint of industrial feasibility. More preferably, it is 10-100 degreeC, Most preferably, it is 20-80 degreeC, Most preferably, it is the range of 20-50 degreeC. From the viewpoint of industrial feasibility, the pressure suitable for carrying out the present invention is in the range of 100 atm from the reduced pressure state, preferably in the range of 1 to 5 atm, and more preferably in the range of 1 to 2 atm. Atmospheric pressure, particularly preferably atmospheric pressure.

  An emulsion is formed by mixing the phase-separated system state under such conditions.

  That is, an emulsion is formed by applying a shearing force to the phase separation solution obtained above.

  In forming the emulsion, the emulsion is formed so that the polyamideimide solution phase becomes particulate droplets. Generally, when the volume of the different polymer solution phase is larger than the volume of the polyamideimide solution phase after phase separation. , The emulsion in such a form tends to be easily formed, and the volume ratio of the polyamideimide solution phase is particularly preferably 0.4 or less with respect to the total volume 1 of both phases, 0.4 to 0.1 It is preferable to be between. When preparing the phase diagram, it is possible to set an appropriate range by simultaneously measuring the volume ratio in the concentration of each component.

  The polyamideimide fine particles obtained by this production method become fine particles having a small particle size distribution, because a very uniform emulsion can be obtained at the stage of emulsion formation. This tendency is remarkable when a single solvent that dissolves both polyamideimide and a different polymer is used. For this reason, in order to obtain a sufficient shearing force to form an emulsion, it is sufficient to use stirring by a conventionally known method, such as a liquid phase stirring method using a stirring blade, a stirring method using a continuous biaxial mixer, or a homogenizer. They can be mixed by a generally known method such as a mixing method or ultrasonic irradiation.

  In particular, in the case of stirring with a stirring blade, although depending on the shape of the stirring blade, the stirring speed is preferably 50 rpm to 1200 rpm, more preferably 100 rpm to 1000 rpm, still more preferably 200 rpm to 800 rpm, and particularly preferably 300 rpm to 600 rpm.

  Specific examples of the stirring blade include a propeller type, a paddle type, a flat paddle type, a turbine type, a double cone type, a single cone type, a single ribbon type, a double ribbon type, a screw type, and a helical ribbon type. However, it is not particularly limited as long as a sufficient shearing force can be applied to the system. Moreover, in order to perform efficient stirring, you may install a baffle plate etc. in a tank.

  In order to generate an emulsion, not only a stirrer but also a widely known device such as an emulsifier and a disperser may be used. Specifically, a batch emulsifier such as a homogenizer (manufactured by IKA), polytron (manufactured by Kinematica), TK auto homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), Ebara Milder (manufactured by Ebara Seisakusho) , TK fill mix, TK pipeline homomixer (manufactured by Koki Kogyo Co., Ltd.), colloid mill (manufactured by Shinko Pantech Co., Ltd.), slasher, trigonal wet pulverizer (manufactured by Mitsui Miike Chemical Co., Ltd.), ultrasonic homogenizer, static For example, a mixer.

  The emulsion thus obtained is subsequently subjected to a step of precipitating polyamideimide fine particles.

  In order to obtain polyamideimide fine particles, polyamideimide fine particles are deposited with a diameter corresponding to the emulsion diameter by bringing a poor solvent for polyamideimide into contact with the emulsion produced in the above-described step.

  The contact method of the poor solvent and the emulsion may be a method of putting the emulsion in the poor solvent or a method of putting the poor solvent in the emulsion, but a method of putting the poor solvent in the emulsion is preferable.

  At this time, the method for introducing the poor solvent is not particularly limited as long as the polyamideimide fine particles produced in the present invention are obtained, and any of the continuous dropping method, the divided addition method, and the batch addition method may be used. In order to prevent the emulsion from agglomerating, fusing and coalescing to increase the particle size distribution and to easily generate a lump exceeding 1000 μm, the continuous dropping method and the divided dropping method are preferable. In order to carry out efficiently, the continuous dropping method is most preferable.

  The time for adding the poor solvent is from 10 minutes to 50 hours, more preferably from 30 minutes to 10 hours, and further preferably from 1 hour to 5 hours.

  If the time is shorter than this range, the particle size distribution may increase or a lump may be generated due to the aggregation, fusion and coalescence of the emulsion. Moreover, when it implements in the time longer than this, when industrial implementation is considered, it is unrealistic.

  By carrying out within this time range, when converting from emulsion to polyamideimide fine particles, aggregation between particles can be suppressed, and polyamideimide fine particles having a small particle size distribution can be obtained.

  The amount of the poor solvent to be added depends on the state of the emulsion, but is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 1 part by mass of the total emulsion. Parts, more preferably 0.2 parts by weight to 3 parts by weight, particularly preferably 0.2 parts by weight to 1 part by weight, most preferably 0.2 parts by weight to 0.5 parts by weight. is there.

  The contact time between the poor solvent and the emulsion may be a sufficient time for the polyamideimide fine particles to precipitate. However, in order to cause sufficient precipitation and obtain efficient productivity, 5 times after the addition of the poor solvent is completed. Min to 50 hours, more preferably 5 minutes to 10 hours, even more preferably 10 minutes to 5 hours, particularly preferably 20 minutes to 4 hours, and most preferably 30 minutes. This is within 3 hours.

  Polyamideimide fine particle dispersions thus produced are usually known, such as filtration, decantation, vacuum filtration, pressure filtration, centrifugation, centrifugal filtration, spray drying, acid precipitation, salting out, freeze coagulation and the like. The fine particle powder can be recovered by solid-liquid separation by this method.

  The solid-liquid separated polyamideimide microparticles are purified with a solvent or the like as necessary to remove attached or contained impurities and the like. In this case, the preferred solvent is the above poor solvent, and more preferably one or more mixed solvents selected from water, methanol, and ethanol.

  The obtained polyamideimide fine particles can be dried to remove the residual solvent. In this case, examples of the drying method include air drying, heat drying, reduced pressure drying, and freeze drying. The temperature for heating is preferably lower than the glass transition temperature, and specifically 50 to 150 ° C is preferable.

  In the method of the present invention, it is advantageous that the organic solvent and the heterogeneous polymer separated in the solid-liquid separation step performed when the polyamideimide fine particles are obtained can be recycled.

  The solvent obtained by solid-liquid separation is a mixture of a heterogeneous polymer, an organic solvent and a poor solvent. By removing the poor solvent from this solvent, it can be reused as a solvent for forming an emulsion. The method for removing the poor solvent is usually performed by a known method, and specific examples include simple distillation, vacuum distillation, precision distillation, thin film distillation, extraction, membrane separation, and the like. This is a method by distillation or precision distillation.

  When performing distillation operations such as simple distillation and vacuum distillation, it is preferable to carry out in a state free of oxygen as much as possible because it takes heat to the system and may promote thermal decomposition of different polymers and organic solvents. Preferably, it is performed under an inert atmosphere. Specifically, it is carried out under nitrogen, helium, argon, carbon dioxide conditions.

  A method of carbonizing and firing the polyamideimide fine particles thus obtained will be described.

  Carbonization firing is usually performed by heating the polyamideimide fine particles in an atmosphere in which a substance that reacts with the polyamideimide fine particles does not exist. Preferably, an inert gas such as helium, argon or nitrogen is used. The atmosphere during heating may be either a flow system or a closed system, but the flow system is preferable because the gas generated by heating can be removed. The pressure during heating may be under pressure or under reduced pressure, but is usually carried out under normal pressure. The heating temperature in normal pressure should just be 400 degreeC or more, Preferably it is 800 degreeC or more.

  The degree of graphitization of the carbon fine particles tends to be higher as the heating temperature is higher and the holding time of the heating temperature is longer. The preferred heating temperature is 400 ° C. or higher, more preferably 800 ° C. or higher, and most preferably 1000 ° C. or higher. Although there is no limitation in particular as an upper limit, it is 3000 degreeC normally, Preferably it is 2500 degrees C or less.

  The rate of temperature increase to the heating temperature is usually 20 ° C./min or less, preferably 10 ° C./min or less, more preferably 5 ° C./min or less. When the firing temperature exceeds 20 ° C./min, the fine particles tend to be fused with each other.

  Although the holding time of the heating temperature varies depending on the heating temperature, a preferable lower limit is 0.5 hour or more, more preferably 1 hour or more, further preferably 5 hours or more, particularly preferably 10 hours or more, and extremely preferably , 50 hours or more, and a preferable upper limit is 1000 hours or less, more preferably 500 hours or less, and still more preferably 100 hours or less. Furthermore, the heating temperature may be maintained at an appropriate temperature for a certain period of time, and further raised to a desired heating temperature.

  In the case of calcining and firing the polyamideimide fine particles, it is possible to use the above method, but by performing the pretreatment described below, the polyamideimide fine particles form a flame-resistant structure and improve the carbonization yield. And the fusion between fine particles can be suppressed.

  A flameproof structure can be formed by heating the polyamideimide fine particles in an oxidizing atmosphere. Under an oxidizing atmosphere is an atmosphere containing oxygen, sulfur, etc., but preferably under air. Although there will be no restriction | limiting in particular if heating temperature forms a flameproof structure, It is 100-300 degreeC, Preferably it is 150-250 degreeC. If the heating temperature is less than 100 ° C., the flameproof structure does not proceed, and if it exceeds 300 ° C., the polyamideimide fine particles melt before forming the flameproof structure. The rate of temperature rise to the heating temperature is usually 20 ° C./min or less, preferably 10 ° C./min, more preferably 5 ° C./min. When the firing temperature exceeds 20 ° C./min, it is not preferable because the fine particles are fused. Moreover, you may hold | maintain heating temperature for a fixed time, after heating to predetermined temperature. The holding time varies depending on the heating temperature, but a holding time of 0.5 to 10 hours, preferably 0.5 to 5 hours is sufficient. Furthermore, the heating temperature may be maintained at an appropriate temperature for a certain period of time, and further raised to a desired heating temperature.

  According to the method for producing carbon fine particles of the present invention, it is possible to easily obtain carbon fine particles having good quality, narrow particle size distribution, and high degree of graphitization.

  The number average particle size of the carbon fine particles obtained as described above is usually 100 μm or less as an upper limit, preferably 50 μm or less, and more preferably 30 μm or less. Moreover, as a minimum, it is 0.1 micrometer or more normally, More preferably, it is 0.5 micrometer or more, More preferably, it is 0.7 micrometer or more, Most preferably, it is 1 micrometer or more. When the number average particle size is too small, the handleability is deteriorated, and when the number average particle size is too large, the dispersibility in a resin or the like is deteriorated.

  The number average particle diameter of the carbon fine particles is calculated from the following formula (1) by observing 100 arbitrary particles in a scanning electron micrograph and measuring the diameter. When the particle is not a perfect circle, the major axis is measured. The carbon particle in the present invention is characterized by a narrow particle size distribution. The particle size distribution of the carbon fine particles of the present invention can be represented by a particle size distribution index, and this particle size distribution index is in the range of 1.0 to 2.0, preferably 1.0 to 1.8. Yes, more preferably 1.0 to 1.5, and particularly preferably 1.0 to 1.3. If the particle size distribution index exceeds this range, the fluidity and filling properties of the resin and the like are lowered, which is not preferable. The particle size distribution index is calculated from the ratio of the volume average particle size to the number average particle size according to the following formula (3). The volume average particle diameter is calculated from the following formula (2) by observing 100 arbitrary particles in a scanning electron micrograph, measuring the diameter. When the particle is not a perfect circle, the major axis is measured.

  Ri: particle diameter of each particle, n: number of measurement 100, Dn: number average particle diameter, Dv: volume average particle diameter, PDI: particle diameter distribution index.

  The carbon of the carbon fine particles of the present invention may be amorphous carbon, graphite-like carbon, crystallized graphite having a graphite layer having a laminated structure, or diamond-like carbon composed of sp3 bonds. Or a mixture. Preferably, it is graphite-like carbon, crystallized graphite in which the graphite layer has a laminated structure, or a mixture thereof, and more preferably a mixture of graphite-like carbon and crystallized graphite in which the graphite layer has a laminated structure.

  The degree of graphitization of the carbon fine particles in the present invention is preferably as high as possible, but is preferably 0.9 or more, more preferably 1.0 or more, and still more preferably 1.2 or more. A graphitization degree of less than 1.0 is not preferable because, for example, electrical conductivity, thermal conductivity, and the like are lowered. Although there is no restriction | limiting in particular about an upper limit, Usually, it is about 3.0.

The degree of graphitization is determined by Raman shift (A) (D derived from defects of amorphous carbon and graphite) found in the vicinity of Raman spectrum 1350 ± 100 cm ⁻¹ measured with a laser beam having a wavelength of 532 nm by Raman spectroscopy. Band), calculated from the height ratio (B) / (A) of Raman shift (B) (G-band derived from graphite) found in the vicinity of 1590 ± 100 cm ⁻¹ .

  The carbon fine particles in the present invention can be produced in a shape close to a true sphere. The sphericity of the carbon fine particles in the present invention is usually 80 or more, preferably 85 or more, more preferably 90 or more, particularly preferably 92 or more, more preferably 95 or more, and particularly preferably 99 or more. Such carbon fine particles can be produced according to the preferred embodiment. When the sphericity is too small, the filling property to the resin or the like is deteriorated, which is not preferable. The sphericity is calculated according to the formula (4) from the average of 30 arbitrary particles by observing particles with a scanning electron microscope, measuring the short diameter and the long diameter.

  Note that n is 30 measurements.

  Since the carbon fine particles obtained by the present invention have good quality and a narrow particle size distribution, they exhibit high dispersibility and filling properties in resins and rubbers, and have a high degree of graphitization. It can be suitably used for conductive rubber, anisotropic conductive particles, chromatography carrier, molecular adsorbent, toner, negative electrode material for lithium ion battery, catalyst carrier, activated carbon, capacitor electrode and the like.

  Next, the present invention will be described in more detail based on examples. The present invention is not limited to these examples. In the examples, the measurements used are as follows.

(1) Measurement of weight average molecular weight The weight average molecular weight was calculated by using a gel permeation chromatography method and comparing it with a calibration curve using polystyrene.
Apparatus: LC-10A series manufactured by Shimadzu Corporation Column: KD-806M manufactured by Showa Denko KK
Mobile phase: 10 mmol / L Lithium bromide / dimethylformamide solution Flow rate: 1.0 ml / min
Detection: differential refractometer column temperature: 40 ° C.

(2) Number-average particle size, volume-average particle size, and particle size distribution index calculation method The particles were observed with a scanning electron microscope (JEOL scanning electron microscope JSM-6301NF), and the number-average particle size was measured. did. When the particles were not perfect circles, the major axis was measured as the particle diameter.

  The number average particle diameter (Dn) and the volume average particle diameter (Dv) were calculated from the average of 100 arbitrary particles according to the formulas (1) and (2).

  The particle size distribution index (PDI) was calculated according to Equation (3).

  Ri: particle diameter of each particle, n: number of measurement 100, Dn: number average particle diameter, Dv: volume average particle diameter, PDI: particle diameter distribution index.

(3) Measurement of sphericity The particles are observed with a scanning electron microscope (JSM-6301NF, manufactured by JEOL Ltd.), the minor axis and the major axis are measured, and an equation is calculated from the average of 30 arbitrary particles. Calculated according to (4).

  Note that n is 30 measurements.

(4) Degree of graphitization Carbon fine particles were placed in a resonance Raman spectrometer (INF-300 manufactured by Horiba Joban Yvon), and measurement was performed using a laser beam having a wavelength of 532 nm, and 1360 ± 100 cm ⁻¹ (A) and 1580 ± 100 cm. ^-1 Height ratio (B) / (A) of (B) was calculated.

[Production Example 1]
In a reaction vessel equipped with a reflux tube and a stirring blade, 15 parts by mass of polyamideimide (TI 5013E-P manufactured by Toray Industries, Inc.), 30 parts by mass of N-methyl-2-pyrrolidinone, polyvinyl alcohol (Nippon Synthetic Chemical) “GOHSENOL (registered trademark)” GL-05 manufactured by Kogyo Co., Ltd., 5 parts by mass of weight average molecular weight 10,600, SP value 32.8 (J / cm ³ ) ^1/2 ) were added, and heated at 80 ° C., Stirring was performed until all the polymer was dissolved. After returning the temperature of the system to room temperature, while stirring at 450 rpm, 50 parts by mass of ion-exchanged water as a poor solvent is dropped at a speed of 3.2 parts by mass / minute via a liquid feed pump. Was precipitated. The obtained fine particles were isolated, washed with water, and dried. The number average particle size of the obtained polyamideimide fine particles was 21.4 μm, the particle size distribution index was 1.22, and the sphericity was 97. The SP value of this polymer was 31.0 (J / cm ³ ) ^1/2 according to the calculation method. A scanning electron micrograph of the obtained fine particles is shown in FIG. FIG. 1 is a scanning electron micrograph of the polyamideimide fine particles obtained here.

[Production Example 2]
In a reaction vessel equipped with a reflux tube and a stirring blade, 5 parts by mass of polyamideimide (TI 5013E-P manufactured by Toray Industries, Inc., weight average molecular weight 66,000), 40 parts by mass of dimethyl sulfoxide, polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) Gohsenol (registered trademark) 'GL-05, weight average molecular weight 10,600, SP value 32.8 (J / cm ³ ) ^1/2 ) 5 parts by mass are added and heated at 80 ° C. to dissolve all polymers. Stirring was continued until After returning the temperature of the system to room temperature, while stirring at 450 rpm, 50 parts by mass of ion-exchanged water as a poor solvent is dropped at a speed of 0.4 parts by mass / min via a liquid feed pump, and particles Was precipitated. The obtained fine particles were isolated, washed with water, and dried. The number average particle size of the obtained polyamideimide fine particles was 4.9 μm, the particle size distribution index was 1.41, and the sphericity was 97. The SP value of this polymer was 31.0 (J / cm ³ ) ^1/2 according to the calculation method.

[Example 1]
10.0 g of polyamideimide fine particles prepared in Production Example 1 were placed in a magnetic dish, heated in a muffle furnace (FP41, manufactured by Yamato Scientific Co., Ltd.) to 250 ° C. over 50 minutes, and held for 1 hour. Thereafter, the temperature was raised to 1000 ° C. over 3 hours and 30 minutes under a nitrogen stream to obtain 5.5 g of carbon fine particles. The obtained carbon fine particles have a number average particle size of 18.6 μm, a particle size distribution index of 1.30, a sphericity of 94, and a height ratio (B) / (A) that is an index of the degree of graphitization. Was 1.00. A scanning electron micrograph of the carbon fine particles obtained is shown in FIG. FIG. 2 is a scanning electron micrograph of carbon fine particles obtained by carbonizing and firing the obtained polyamideimide fine particles.

[Example 2]
10.0 g of polyamideimide fine particles prepared in Production Example 2 were placed in a magnetic dish, heated to 1000 ° C. over 6 hours and 40 minutes in a muffle furnace (FP41, manufactured by Yamato Scientific Co., Ltd.), and carbon fine particles 2 0.7 g was obtained. The number average particle size of the obtained carbon fine particles is 4.1 μm, the particle size distribution index is 1.29, the sphericity is 96, and the height ratio (B) / (A) which is an index of the degree of graphitization. Was 1.02.

[Comparative Example 1]
Carbon fine particles were prepared according to Patent Document 1 (Japanese Patent Laid-Open No. 63-129006) as a method for producing carbon fine particles from phenol resin fine particles, which is known as a method for carbonizing and firing a carbon fine particle precursor formed by polymerization. That is, 100 parts by mass of a mixed aqueous solution composed of 18 parts by mass of hydrochloric acid and 9 parts by mass of formaldehyde was added to the reaction vessel, 3.3 parts by mass of an aqueous solution of phenol / water = 90/10 parts by mass was added, and the mixture was stirred for 60 seconds. When the stirring was stopped and the mixture was allowed to stand, the inside of the system gradually became cloudy, and a pink resinous product was observed after 30 minutes. Next, while stirring, the temperature was raised to 80 ° C. over 60 minutes and held for 20 minutes. After being isolated and washed with water, it was treated with 0.2 parts by mass of an aqueous ammonia solution at 60 ° C. for 60 minutes, washed with water, and dried at a temperature of 100 ° C. to obtain phenol / formaldehyde resin particles. . The number average particle size of the phenol / formaldehyde resin particles was 19.2 μm, the particle size distribution index was 2.79, and the sphericity was 57. 9.2 g of the obtained particles are placed in a magnetic dish, heated in a muffle furnace (FP41, manufactured by Yamato Kagaku Co., Ltd.) in a nitrogen stream, heated to 800 ° C. over 2 hours, and held for 80 minutes to obtain 2.7 g of carbon fine particles. Got. The obtained carbon fine particles have a number average particle size of 10.1 μm, a particle size distribution index of 2.84, a sphericity of 86, and a height ratio (B) / (A) that is an index of the degree of graphitization. Was 0.85.

Claims (7)

A method for producing carbon fine particles, comprising calcining and firing polyamideimide fine particles. In a system in which polyamideimide and a polymer different from polyamideimide are mixed in an organic solvent and phase-separated into a solution phase mainly composed of polyamideimide and a solution phase mainly composed of a different polymer, an emulsion is formed. 2. The method for producing carbon fine particles according to claim 1, wherein the polyamideimide fine particles are produced by depositing polyamideimide by contacting with a poor solvent of polyamideimide to obtain polyamideimide fine particles. The method for producing carbon fine particles according to claim 1, wherein the number average particle diameter of the carbon fine particles is 0.1 to 100 μm. The method for producing carbon fine particles according to any one of claims 1 to 3, wherein the particle size distribution index of the carbon fine particles is 1.0 to 2.0. 5. The method for producing carbon fine particles according to claim 1, wherein the sphericity of the carbon fine particles is 80 or more. 6. The method for producing carbon fine particles according to claim 1, wherein the degree of graphitization of the carbon fine particles is 1.0 or more. Carbon fine particles obtained by the production method according to claim 1.

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