JP5488446B2 - Carbon fine particles and method for producing the same - Google Patents

Description

  The present invention relates to fine carbon particles having a narrow particle size distribution and high quality, 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 there is a need for carbon fine particles with good quality and narrow particle size distribution in order to further increase the functionality in the future.

  Conventionally, a method for producing fine carbon particles has disclosed a method in which coke, pitch, and the like, which are 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 a production method in which phenol / formaldehyde resin fine particles are baked, the phenol / formaldehyde fine particles obtained by polycondensation of phenol and formaldehyde as raw materials have a wide particle size distribution, and the resulting carbon fine particles have a wide particle size distribution accordingly. (Patent Document 1). On the other hand, when producing carbon fine particles from polyacrylonitrile-based polymer fine particles, since the fine particles are produced by polymerization, in water-based polymerization with a high copolymerization ratio of polyacrylonitrile, it is easy to agglomerate and it is difficult to control the reaction. It is disclosed that the diameter distribution is 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 carbon fine particles having a narrow particle size distribution and good quality by an industrially simple method.

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 simple method for producing fine carbon particles having a narrow particle size distribution and high quality, and further 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 synthetic resin fine particles having a narrow particle size distribution.

That is, the present invention has the following configuration.
[1] Polyolefin copolymers, polyacrylonitrile copolymers composed of copolymers of acrylonitrile monomers and hydrophilic vinyl monomers, polyacrylamide polymers, polyvinyl acetate polymers, polychlorinated A polymer A selected from the group consisting of vinyl polymers, polyvinylidene chloride polymers, polyamides, polyarylene ethers, polyarylene sulfides, polysulfones, polyether ketones, polyether ether ketones, polyarylates, and polyimides; In the system in which the polymer A and the different polymer B are mixed in an organic solvent and phase-separated into a solution phase containing the polymer A as a main component and a solution phase containing the polymer B as a main component, after forming an emulsion, the polymer By contacting the poor solvent of A, polymer A is precipitated The method of manufacturing the carbon particles, characterized in that to produce Rimmer particles, the resulting polymer particles to carbonization,
[2] the polymer A, characterized in that a polyacrylic nitrile copolymer comprising a copolymer of acrylonitrile monomer and a hydrophilic vinyl monomer [1] Production of carbon microparticle according Method,
[3] A polyacrylonitrile-based copolymer composed of a copolymer of an acrylonitrile-based monomer and a hydrophilic vinyl monomer is more than 0 to 25 parts by weight of hydrophilic vinyl with respect to 100 parts by weight of the acrylonitrile-based monomer. [1] or [2] carbon fine particle production method according to [1], which is an acrylonitrile copolymer obtained by copolymerizing monomers,
[4] Any one of [1] to [3], wherein the hydrophilic vinyl monomer contains at least one hydroxyl group, carboxyl group, amino group, amide group, sulfonic acid group, and phosphoric acid group The method for producing the carbon fine particles described
[5] The method for producing carbon fine particles according to any one of [1] to [4], wherein the hydrophilic vinyl monomer contains one or more amide groups or carboxyl groups,
[6] The carbon fine particle according to any one of [1] to [5], wherein the hydrophilic vinyl monomer is at least one selected from acrylic acid, methacrylic acid, itaconic acid and acrylamide. Production method,
[7] The method for producing carbon fine particles according to any one of [1] to [6], wherein the degree of graphitization is 1.0 or more,
[8] The method for producing carbon fine particles according to any one of [1] to [7], wherein the number average particle size is 0.1 to 100 μm and the particle size distribution index is 1.0 to 2.0.
[9] The number average particle size is 0.1 to 100 μm, the particle size distribution index is 1.0 to 2.0, the degree of graphitization is 1.0 or more, and the sphericity is 80 or more. 1] - [8] the method of producing carbon microparticle according to any one,
It is.

  According to the method for producing carbon fine particles of the present invention, it is possible to easily obtain carbon fine particles having a narrow particle size distribution and a high graphitization degree and good quality. Since the carbon fine particles obtained by the present invention have a narrow particle size distribution, they exhibit high dispersibility and filling properties in resins and rubbers, and also have a high degree of graphitization, so that resin modifiers, conductive rubbers, It can be suitably used for directionally conductive particles, chromatography carriers, molecular adsorbents, toners, negative electrode materials for lithium ion batteries, catalyst carriers, activated carbon, capacitor electrodes, and the like.

2 is a scanning electron micrograph of polyacrylonitrile copolymer fine particles obtained in Production Example 1. FIG. 4 is a scanning electron micrograph of polyacrylonitrile polymer fine particles obtained in Production Example 2. FIG. 2 is a scanning electron micrograph of carbon fine particles obtained in Example 1. FIG. 3 is a scanning electron micrograph of carbon fine particles obtained in Comparative Example 2.

  The present invention will be described in more detail below.

  The carbon fine particles in the present invention are fine particles consisting essentially of carbon.

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

  The carbon microparticles in the present invention are a polymer to be micronized, a polyolefin copolymer, a polyacrylonitrile copolymer comprising a copolymer of an acrylonitrile monomer and a hydrophilic vinyl monomer, a polyacrylamide polymer. Polymer, polyvinyl acetate polymer, polyvinyl chloride polymer, polyvinylidene chloride polymer, polyamide, polyarylene ether, polyarylene sulfide, polysulfone, polyether ketone, polyether ether ketone, polyarylate, polyimide A solution phase comprising, as a main component, polymer A, wherein polymer A selected from at least one group and polymer B different from polymer A (hereinafter sometimes referred to as different polymer B or polymer B) are mixed in an organic solvent. And phase separation into solution phase mainly composed of polymer B In the system, after forming an emulsion, a polymer A is precipitated by contacting with a poor solvent of the polymer A, and then fine particles are obtained. Then, the obtained polymer fine particles are carbonized and fired to produce carbon fine particles. It is a method to do.

  By the above method, fine carbon particles having a narrow particle size distribution and high quality can be obtained. Since the degree of graphitization becomes higher and carbon fine particles with better quality can be produced, among the above polymers A, a polyacrylonitrile system comprising a copolymer of an acrylonitrile monomer and a hydrophilic vinyl monomer It is preferable to use a copolymer, polyamide, polyarylene ether, polyarylene sulfide, polysulfone, polyetherketone, polyetheretherketone, polyarylate, polyimide, and acrylonitrile is less likely to cause fusion between particles during carbonization. Particularly preferred are polyacrylonitrile-based copolymers, polyetherimides, and polyimide fine particles comprising a copolymer of a acrylonitrile-based monomer and a hydrophilic vinyl monomer, and the copolymer of an acrylonitrile-based monomer and a hydrophilic vinyl monomer. A polyacrylonitrile copolymer consisting of a polymer is It is also preferred.

  Examples of the polyolefin copolymer include polyethylene, polypropylene, and copolymers thereof.

  Examples of the copolymer component include cyclopentene, dicyclopentadiene and derivatives thereof, cyclohexene, dicyclohexadiene and derivatives thereof, and the like.

  The polyacrylonitrile copolymer is a polyacrylonitrile copolymer composed of a copolymer of an acrylonitrile monomer and a hydrophilic vinyl monomer as described above. The acrylonitrile monomer is represented by the following general formula (1).

In this case, in the above formula, R ¹ and R ² are selected from substituents such as a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a halogen group, a hydroxyl group, an alkoxyl group, an ester group, a carboxyl group, and a sulfonic acid group. Indicates which one will be. These may be the same or different.

  Of these, preferred are a hydrogen atom, a methyl group, an ethyl group, and an isopropyl group, more preferred are a hydrogen atom, a methyl group, and an ethyl group, and particularly preferred are a hydrogen atom and a methyl group. Specific examples of such acrylonitrile monomers include (meth) acrylonitrile and chloroacrylonitrile. These can be used alone or in combination of two or more thereof. Most preferred is acrylonitrile.

  Examples of the hydrophilic vinyl monomer include unsaturated monomers in which at least one hydroxyl group, carboxyl group, amino group, amide group, sulfonic acid group and phosphoric acid group are substituted. Specifically, unsaturated monomers substituted with hydroxyl groups such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, (meth) acrylic acid, itaconic acid, crotonic acid Carboxylic acids such as fumaric acid, maleic acid, citraconic acid, methaconic acid, glutaric acid, tetrahydrophthalic acid, isocrotonic acid, nadic acid, butenetricarboxylic acid, monobutyl fumarate, monoethyl maleate, monomethyl itaconate, p-vinylbenzoic acid Unsaturated monomers substituted with acid groups and salts thereof, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, vinylpyrrolidone, N-methylvinylpyridinium chloride, (meth) allyltriethylammonium Methyl chloride, unsaturated monomer substituted with tertiary amino group such as 2-hydroxy-3- (meth) acryloyloxypropyltrimethylammonium chloride, or quaternary ammonium salt, (meth) acrylamide, N-hydroxyalkyl ( Unsaturated monomers substituted with amide groups such as (meth) acrylamide, N-alkyl (meth) acrylamide, N, N-dialkyl (meth) acrylamide, vinyl lactams, vinyl sulfonic acid, methyl vinyl sulfonic acid, styrene sulfonic acid , (Meth) acrylic sulfonic acid, ethyl (meth) acrylic acid-2-sulfonic acid, unsaturated monomer substituted with sulfonic acid group such as 2-acrylamido-2-hydroxypropane sulfonic acid, (meth) acrylic acid- 3-chloro-2-propyl phosphate, (meth) acryl Acid-2-phosphoric acid ethyl unsaturated monomer substituted with a phosphate group such as 3-allyloxy-2-hydroxypropane phosphate. Since the effect of suppressing fusion between fine particles at the time of firing is high, an unsaturated monomer substituted with at least one carboxyl group and amide group, particularly preferably (meth) acrylic acid, itaconic acid, (Meth) acrylamide is mentioned. These can be used alone or in combination of two or more thereof.

  The copolymerization amount of the hydrophilic vinyl monomer unit is preferably more than 0 to 25 parts by mass with respect to 100 parts by mass of the acrylonitrile monomer. A more preferred upper limit is 20 parts by mass, and a still more preferred upper limit is 15 parts by mass, particularly preferably 10 parts by mass, and extremely preferably 5 parts by mass. Moreover, as a more preferable minimum, it is 0.5 mass part, More preferably, it is 1 mass part, Especially preferably, it is 2 mass parts. When the hydrophilic vinyl unit exceeds this range, the degree of graphitization of the carbon fine particles tends to decrease.

  In the present invention, the polyacrylonitrile copolymer composed of a copolymer of an acrylonitrile monomer and a hydrophilic vinyl monomer is within the above range, and other copolymerizable unsaturated monomers are copolymerized. Polymerization may be performed. These may be polyfunctional monomers.

  Specific examples of the other copolymerizable unsaturated monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and n-butyl (meth) acrylate. T-butyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, chloromethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, (meth) acrylic acid 2 -Hydroxyethyl, 3-hydroxypropyl (meth) acrylate, 2,3,4,5,6-pentahydroxyhexyl (meth) acrylate and 2,3,4,5-tetrahydroxypentyl (meth) acrylate, Unsaturated carboxylic acid alkyl ester monomers such as phenyl (meth) acrylate and benzyl (meth) acrylate, styrene, α-methylstyrene , Aromatic such as 1-vinylnaphthalene, 3-methylstyrene, 4-propylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, 4- (phenylbutyl) styrene, halogenated styrene Vinyl monomer, butadiene, isoprene, 2,3-dimethylbutadiene, 2-methyl-3-ethylbutadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 2-ethyl-1,3- Pentadiene, 1,3-hexadiene, 2-methyl-1,3-hexadiene, 3,4-dimethyl-1,3-hexadiene, 1,3-heptadiene, 3-methyl-1,3-heptadiene, 1,3- Examples thereof include conjugated diene monomers such as octadiene, cyclopentadiene, chloroprene, and myrcene. These can be used alone or in combination of two or more thereof.

  Of these, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, t-butyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, styrene, and butadiene are particularly preferable. ) Methyl acrylate and ethyl (meth) acrylate are preferred.

  Other polyfunctional monomers that can be copolymerized are monomers having two or more carbon-carbon double bonds in the molecule, such as allyl (meth) acrylate and methallyl (meth) acrylate. , Allyl cinnamate, methallyl cinnamate, diallyl maleate, diallyl phthalate, diallyl terephthalate, diallyl isophthalate, divinylbenzene, ethylene di (meth) acrylate, butanediol di (meth) acrylate, hexanediol di (meth) acrylate, Trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) Acrylate, and the like. These can be used alone or in combination of two or more thereof. Of these, allyl (meth) acrylate, diallyl maleate, diallyl phthalate, divinylbenzene, ethylene di (meth) acrylate, polyethylene glycol di (meth) acrylate, and polypropylene glycol di (meth) acrylate are preferred, and allyl (meth) acrylate is particularly preferred. , Diallyl maleate, divinylbenzene, and ethylene di (meth) acrylate are preferred.

  The copolymerization amount of other unsaturated monomers that can be copolymerized is 0 to 25 parts by mass, preferably 0 to 15 parts by mass, and more preferably 0 to 100 parts by mass of the acrylonitrile monomer. -5 parts by mass. Note that when the copolymerization amount of other copolymerizable monomers exceeds 25 parts by mass, the degree of graphitization of the carbon fine particles tends to decrease.

  As a comonomer that is copolymerized with acrylonitrile, a combination of two or more of a hydrophilic vinyl monomer and another copolymerizable monomer as an optional component is (meth) acrylic acid. Methyl and (meth) acrylamide, methyl (meth) acrylate and itaconic acid, methyl (meth) acrylate and (meth) acrylic acid, (meth) acrylamide and (meth) acrylic acid, (meth) acrylamide and itaconic acid, itaconic Acid and (meth) acrylic acid are preferred.

  Examples of the polyamide include polyamides obtained by polycondensation of a lactam having three or more members, a polymerizable aminocarboxylic acid, a dibasic acid and a diamine or a salt thereof, or a mixture thereof.

  Specifically, polycaproamide (nylon 6), polyhexamethylene adipamide (nylon 66), polypentamethylene adipamide (nylon 56), polyhexamethylene sebamide (nylon 610), polyundecamide (Nylon 11), polydodecamide (nylon 12), polyhexamethylene terephthalamide (nylon 6T), amorphous polyamide, 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, isophthalic acid and 12 -Copolymer of aminododecanoic acid (for example, 'Grillamide (registered trademark)' TR55, manufactured by Mzavelke), copolymer of 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane and dodecanedioic acid Coalition (for example, 'Grillamide (registered trademark)' TR90, Mzavelke 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, a copolymer of isophthalic acid and 12-aminododecanoic acid, 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane and dodecane A mixture of an acid copolymer (for example, 'Grillamide (registered trademark)' TR70LX, manufactured by Mzavelke), a copolymer of 4,4'-diaminodicyclohexylmethane and dodecadioic acid (for example, 'TROGAMID (registered trademark)' CX7323, manufactured by Degussa).

  The polyarylene ether is a polymer in which aryl groups are connected by an ether bond, and examples thereof include those having a structure represented by the general formula (2).

  At this time, the aromatic ring may or may not have a substituent R, and the number m of the substituents is 1 or more and 4 or less. Substituents include saturated hydrocarbon groups having 1 to 6 carbon atoms such as methyl, ethyl and propyl groups, unsaturated hydrocarbon groups such as vinyl and allyl groups, halogens such as fluorine, chlorine and bromine atoms. Preferred examples include a group, an amino group, a hydroxyl group, a thiol group, a carboxyl group, and a carboxy aliphatic hydrocarbon ester group.

  Specific examples of polyarylene ether include poly (2,6-dimethylphenylene ether).

  The polyarylene sulfide is a polymer in which aryl groups are connected by a sulfide bond, and includes a polymer having a structure represented by the general formula (3).

  At this time, the aromatic ring may or may not have a substituent R, and the number m of the substituents is 1 or more and 4 or less. Substituents include saturated hydrocarbon groups such as methyl, ethyl and propyl groups, unsaturated hydrocarbon groups such as vinyl and allyl groups, halogen groups such as fluorine, chlorine and bromine, amino groups and hydroxyl groups. Thiol group, carboxyl group, carboxy aliphatic hydrocarbon ester group and the like. Further, instead of the paraphenylene sulfide unit of the general formula (3), a metaphenylene unit or an orthophenylene unit may be used, or a copolymer thereof may be used.

  Specific examples of the polyarylene sulfide include polyphenylene sulfide.

  As polysulfone, what has a structure represented by General formula (4) is mentioned preferably.

(R in the formula represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 8 carbon atoms, and m represents an integer of 0 to 3).

  Polyether ketone is a polymer having an ether bond and a carbonyl group. Specifically, what has a structure represented by General formula (5) is mentioned preferably.

(R in the formula represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 8 carbon atoms, and m represents an integer of 0 to 3).

  Among the polyether ketones, those having a structure represented by the general formula (6) are particularly referred to as polyether ether ketones.

(R in the formula represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 8 carbon atoms, and m represents an integer of 0 to 3).

  The polyarylate is a polyester composed of an aromatic polyhydric alcohol and an aromatic carboxylic acid among polyesters, specifically, a copolymer of bisphenol A or bisphenol F and an aromatic carboxylic acid, Examples include bisphenol A / terephthalic acid, bisphenol A / isophthalic acid, bisphenol A / terephthalic acid / isophthalic acid, bisphenol F / terephthalic acid, bisphenol F / isophthalic acid, and bisphenol F / terephthalic acid / isophthalic acid. "U polymer" can be used.

  The polyimide is a polymer having an imide bond, and typically includes a polymer having a structure represented by the general formula (7).

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

  Particularly in this system, a thermoplastic polyimide is preferable. Specifically, a polycondensate of 1,2,4,5-benzenetetracarboxylic anhydride and 4,4′-bis (3-aminophenyloxy) biphenyl, Examples include polycondensates of 3,3 ′, 4,4′-biphenyltetracarboxylic anhydride and 1,3-bis (4-aminophenyloxy) benzene.

  The weight average molecular weight of the resin 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. It 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 it cannot be measured with dimethylformamide, tetrahydrofuran is used. When it cannot be measured, hexafluoroisopropanol is used. When it cannot be measured with hexafluoroisopropanol, measurement is performed using 2-chloronaphthalene.

  Such synthetic resin fine particles are obtained by, for example, dissolving and mixing a polymer to be finely divided (hereinafter referred to as polymer A), a polymer B dissolved in a poor solvent of the polymer A, and an organic solvent, and a solution phase containing the polymer A as a main component. An emulsion is formed in a system that phase-separates into two phases (hereinafter also referred to as polymer A solution phase) and a solution phase mainly composed of polymer B (hereinafter also referred to as polymer B solution phase). Then, the polymer A can be obtained by a method in which the polymer A is precipitated by contacting with a poor solvent of the polymer A.

  Synthetic resin fine particles made by this method have an arrangement in which the cyclization reaction during carbonization tends to proceed because the folded state of the polymer chain inside the fine particles is thermodynamically stable, so that the cyclization reaction proceeds easily during carbonization. It is considered that the reaction is easy and the degree of graphitization improves when carbonized and fired.

  The above method will be described more specifically.

  In the above, “a system in which polymer A, polymer B, and an organic solvent are dissolved and mixed and phase-separated into two phases of a solution phase mainly composed of polymer A and a solution phase mainly composed of polymer B” means a polymer When A, polymer B, and an organic solvent are mixed, the system is divided into two phases, a solution phase mainly containing polymer A and a solution phase mainly containing polymer B.

  By using such a phase-separating system, it is possible to mix and emulsify under the phase-separating conditions to form an emulsion.

  In the above, whether or not the polymer is dissolved is more than 1% by mass with respect to the organic solvent at the temperature at which this method is carried out, that is, the temperature at which the polymer A and the polymer B are dissolved and mixed to separate into two phases Judged by whether or not to dissolve.

  This emulsion has a polymer A solution phase in the dispersed phase, a polymer B solution phase in the continuous phase, and a polymer A solution in contact with the polymer A poor solvent by contacting the emulsion with the polymer A poor solvent. A is precipitated, and synthetic resin fine particles composed of the polymer A can be obtained.

  In the present method, there is no particular limitation on the combination as long as the synthetic resin fine particles of the present method are obtained using the polymer A, the polymer B, the organic solvent for dissolving them, and the poor solvent for the polymer A.

  In the present method, the polymer A is preferably insoluble in the poor solvent, since the present method is intended to precipitate fine particles when contacting with the poor solvent, and a polymer that does not dissolve in the poor solvent described later is used. A water-insoluble polymer is particularly preferable.

  Here, the water-insoluble polymer is a polymer having a solubility in water of 1% by mass or less, preferably 0.5% by mass or less, and more preferably 0.1% by mass or less.

  Examples of the polymer B include thermoplastic resins and thermosetting resins, but those that are soluble in an organic solvent that dissolves the polymer A used in the present method and a poor solvent for the polymer A are preferable. And what dissolve | melts in an alcohol solvent or water is more preferable at the point which is excellent in industrial handleability, and also what melt | dissolves in an organic solvent and melt | dissolves in methanol, ethanol, or water is especially preferable.

  If the polymer B is specifically exemplified, poly (vinyl alcohol) (which may be completely 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, polystyrenesulfonic acid, poly Sodium styrenesulfonate, polyvinylpyrrolidinium chloride, poly (styrene-maleic acid) copolymer, aminopoly (acrylamide), poly (paravinylphenol), polyallylamine, polyvinyl ether, polyvinyl formal, poly (acrylamide), poly ( Methacrylamide), poly (oxyethyleneamine), poly (vinyl pyrrolidone), poly (vinyl pyridine), polyaminosulfone, polyethyleneimine, and other synthetic resins, disaccharides such as maltose, cellobiose, lactose, sucrose, cellulose, chitosan, hydroxy Ethyl cellulose, hydroxypropyl cellulose, methyl cellulose, ethyl cellulose, ethyl hydroxy cellulose, carboxymethyl ethyl cellulose, carboxymethyl cell Cellulose, cellulose derivatives such as sodium carboxymethylcellulose, 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, Examples include fibroin, keratin, fibrin, carrageenan, chondroitin sulfate, gum arabic, agar, protein, etc., preferably poly (vinyl alcohol) (fully saponified or partially saponified poly (vinyl alcohol)) Good), poly (vinyl alcohol-ethylene) copolymer (may be fully saponified or partially saponified poly (vinyl alcohol-ethylene) copolymer), polyethylene glycol, sucrose fatty acid Ester, poly (oxyethylene alkylphenyl ether), poly (oxyalkyl ether), poly (acrylic acid), poly (methacrylic acid), carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, methylcellulose, ethylcellulose, ethylhydroxycellulose, carboxymethyl Cellulose derivatives such as 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)). ), Poly (vinyl alcohol-ethylene) copolymer (fully saponified or partially saponified poly (vinyl alcohol-ethylene) Polymer), polyethylene glycol, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, methylcellulose, ethylcellulose, ethylhydroxycellulose, carboxymethylethylcellulose, carboxymethylcellulose, carboxymethylcellulose sodium, cellulose ester, and the like, and polyvinylpyrrolidone, particularly preferred Is poly (vinyl alcohol) (may be fully saponified or partially saponified poly (vinyl alcohol)), poly (ethylene glycol), carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, methylcellulose, ethylcellulose, ethyl Cellulose derivatives such as hydroxycellulose, poly Is Nirupiroridon.

  The molecular weight of the polymer B is preferably 1,000 to 100,000,000, more preferably 1,000 to 10,000,000, and still more preferably 5,000 to 1,000,000 in terms of weight average molecular weight. 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 that dissolves the polymer A and the polymer B is an organic solvent that can dissolve the polymer A and the polymer B to be used, and is selected according to the type of each polymer.

  Specific examples include aliphatic hydrocarbon solvents such as pentane, hexane, heptane, octane, nonane, n-decane, n-dodecane, n-tridecane, tetradecane, cyclohexane, cyclopentane, benzene, toluene, xylene, 2- Aromatic hydrocarbon solvents such as methylnaphthalene, ester solvents such as ethyl acetate, methyl acetate, butyl acetate, butyl propionate, butyl butyrate, 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 − Alcohol solvents such as propanol, 2-propanol, N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMA), propylene carbonate , Aprotic polar solvents such as trimethyl phosphoric acid, 1,3-dimethyl-2-imidazolidinone, sulfolane, carboxylic acid solvents such as formic acid, acetic acid, propionic acid, butyric acid, lactic acid, anisole, diethyl ether, tetrahydrofuran, diisopropyl Ether solvents such as ether, dioxane, diglyme, dimethoxyethane, 1-butyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium hydrogen sulfate, 1-ethyl-3-imidazolium acetate Ionic liquids or mixtures thereof, such as 1-ethyl-3-methylimidazolium thiocyanate, and the like. 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-based solvents, aprotic polar solvents, and carboxylic acid solvents that are water-soluble solvents are preferred, and aprotic polar solvents and carboxylic acid solvents are particularly preferable. Most preferred is N-methyl-2-, because it has a wide range of application to polymer A because it 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 or an alcohol solvent. Pyrrolidone, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, propylene carbonate, formic acid, It is an 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 standpoint of reducing the process load in manufacturing, avoiding the troublesome separation step, it is preferable to use a single organic solvent, and it should be a single organic solvent that dissolves both polymer A and polymer B. Is preferred.

  The poor solvent for polymer A in this method refers to a solvent that does not dissolve polymer A. When the solvent is not dissolved, the solubility of the polymer A 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 polymer A is used, and the poor solvent is preferably a poor solvent for polymer A and a solvent that dissolves polymer B. Thereby, the polymer fine particle comprised with the polymer A can be precipitated efficiently. Moreover, it is preferable that the solvent for dissolving the polymer A and the polymer B and the poor solvent for the polymer A are solvents that are uniformly mixed.

  The poor solvent in this method varies depending on the type of polymer A to be used, desirably both types of polymers A and B to be used. Specifically, for example, pentane, hexane, heptane, octane, nonane, n -Aliphatic hydrocarbon solvents such as decane, n-dodecane, n-tridecane, tetradecane, cyclohexane, cyclopentane, etc., aromatic hydrocarbon solvents such as benzene, toluene, xylene, 2-methylnaphthalene, ethyl acetate, methyl acetate Ester solvents such as butyl acetate, butyl propionate and butyl butyrate, chloroform, bromoform, methylene chloride, carbon tetrachloride, 1,2-dichloroethane, 1,1,1-trichloroethane, chlorobenzene, 2,6-dichlorotoluene, Halogenated hydrocarbons such as hexafluoroisopropanol Solvent, ketone solvent such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl butyl ketone, alcohol solvent such as methanol, ethanol, 1-propanol, 2-propanol, dimethyl sulfoxide, N, N-dimethylformamide, N, N -Aprotic polar solvents such as dimethylacetamide, trimethylphosphoric acid, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, sulfolane, carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, lactic acid Examples include acid solvents, ether solvents such as anisole, diethyl ether, tetrahydrofuran, diisopropyl ether, dioxane, diglyme and dimethoxyethane, and a solvent selected from at least one of water.

  From the viewpoint of efficiently atomizing the polymer A, 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, by appropriately selecting and combining the polymer A, the polymer B, the organic solvent for dissolving them, and the poor solvent for the polymer A, the polymer A can be efficiently precipitated to obtain synthetic resin fine particles.

  At this time, the liquid obtained by mixing and dissolving the polymers A and B and the organic solvent for dissolving them is phase-separated into two phases, a solution phase mainly composed of the polymer A and a solution phase mainly composed of the polymer B. is necessary.

  At this time, the solution-phase organic solvent containing polymer A as a main component and the organic solvent containing polymer B as a main component may be the same or different, but may be substantially the same solvent. preferable.

  Conditions for generating a state of two-phase separation vary depending on the types of polymers A and B, the molecular weights of polymers A and B, the types of organic solvents, the concentrations of polymers A and B, the temperature and pressure at which this method is performed. come.

  In order to obtain conditions that are likely to cause a phase separation state, it is preferable that the difference between the solubility parameters of the polymer A and the polymer B (hereinafter also referred to as SP values) 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 polymer A and polymer B can be dissolved in an organic solvent, but the upper limit of the difference in SP value is preferably 20 (J / cm ³ ) ^1/2 or less, more preferably 15 (J / Cm ³ ) ^1/2 or less, more 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 a state in which the ratio of the three components of the polymer A, the polymer B, and the organic solvent in which they are dissolved is changed. Can be distinguished.

  The phase diagram is prepared by mixing and dissolving the polymers A and B and the solvent at an arbitrary ratio and determining whether or not an interface is formed when allowed to stand at least 3 points, preferably 5 points or more. Preferably, the measurement is performed at 10 points or more, 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 it is in a phase-separated state, the polymers A and B are adjusted to any ratio of the polymers A and B and the solvent at the temperature and pressure at which the present invention is to be carried out. Then, the polymers A and B are completely dissolved, and after the dissolution, the mixture is sufficiently stirred and left for 3 days to confirm whether or not the phase separation is performed macroscopically.

  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 into a polymer A solution phase mainly composed of polymer A and a polymer B solution phase mainly composed of polymer B in an organic solvent. At this time, the polymer A solution phase is a phase in which the polymer A is mainly distributed, and the polymer B solution phase is a phase in which the polymer B is mainly distributed. At this time, the polymer A solution phase and the polymer B solution phase seem to have a volume ratio corresponding to the types and amounts of the polymers A and B used.

  The concentration of the polymers A and B with respect to the organic solvent is premised on being within a possible range that can be dissolved in the organic solvent. Are independently 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, since the interfacial tension between the two phases of the polymer A solution phase and the polymer B solution phase is an organic solvent, the interfacial tension is small, and the resulting emulsion can be stably maintained due to its properties. The particle size distribution seems to be smaller. In particular, when the organic solvents of the polymer A phase and the polymer B 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 the polymer A solution phase / polymer solution phase B under the temperature conditions for carrying out the present invention, the preferred range is 0.1 or more and 10 or less, and the more preferred 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.

  Synthetic resin 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 polymer A solution phase becomes particulate droplets. However, when the volume of the polymer B solution phase is larger than the volume of the polymer A solution phase after phase separation is generally performed. The emulsion in such a form tends to be easily formed, and the volume ratio of the polymer A 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 synthetic resin 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 the polymers A and B 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 depositing synthetic resin fine particles.

  In order to obtain the synthetic resin fine particles, a poor solvent for the polymer A is brought into contact with the emulsion produced in the above-described step, so that the synthetic resin fine particles are deposited with a diameter corresponding to the emulsion diameter.

  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 synthetic resin 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 even more 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 synthetic resin fine particles, aggregation between particles can be suppressed, and synthetic resin 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 to 3 parts by weight, particularly preferably 0.2 to 1 part by weight, and most preferably 0.2 to 0.5 parts by weight.

  The contact time between the poor solvent and the emulsion may be a time sufficient for the synthetic resin fine particles to precipitate. However, in order to cause sufficient precipitation and to 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.

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

  The synthetic resin fine particles separated by solid-liquid separation are purified with a solvent or the like, if 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 synthetic resin 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 polymer B separated in the solid-liquid separation step performed when the synthetic resin fine particles are obtained can be used for recycling.

  The solvent obtained by solid-liquid separation is a mixture of polymer B, 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 from oxygen as much as possible because heat is applied to the system and the thermal decomposition of the polymer B and the organic solvent may be accelerated. Preferably, it is performed under an inert atmosphere. Specifically, it is carried out under nitrogen, helium, argon, carbon dioxide conditions.

  The synthetic resin fine particles thus obtained usually have a number average particle size of about 100 μm or less, are not only fine particles having a narrow particle size distribution and high sphericity, but also high quality carbon fine particles derived from the production method. Can give.

  The number average particle diameter of the synthetic resin fine particles is usually 100 μm or less, preferably 50 μm or less, more preferably 30 μm or less as the upper limit. 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.

  Synthetic resin fine particles having a narrow particle size distribution can be obtained by the above method. The particle size distribution of the synthetic resin fine particles can be represented by a particle size distribution index, and is usually in the range of 1.0 to 2.0, preferably 1.0 to 1.8, more preferably 1.0. It is -1.5, Most preferably, it is 1.0-1.3. Synthetic resin fine particles having a narrow particle size distribution tend to give carbon fine particles having a narrow particle size distribution. Therefore, it is preferable that the particle size distribution index is in the above range 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.

  Synthetic resin fine particles with high sphericity can be obtained by the above method. The sphericity of the synthetic resin fine particles used in the present invention is usually 80 or more, preferably 85 or more, more preferably 90 or more, more preferably 92 or more, particularly preferably 95 or more, and most preferably 99 or more. Synthetic resin fine particles having a high sphericity tend to give carbon particles having a high sphericity. Therefore, if the sphericity is within the above range, spherical carbon fine particles can be easily 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.

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

  The carbonization firing is performed by heating the synthetic resin fine particles in an atmosphere in which a substance that reacts with the synthetic resin 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 usually 3000 degreeC, More 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 carbonizing and firing synthetic resin fine particles, it is possible to use the above method, but by performing the pretreatment described below, the synthetic resin fine particles form a flame-resistant structure and the carbonization yield is improved. And the fusion between fine particles can be suppressed.

  It is possible to form a flameproof structure by heating the synthetic resin 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 synthetic resin fine particles melt before the flameproof structure is formed. 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, 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.

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

  The number average particle diameter of the carbon fine particles of the present invention is 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. 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 fine particles in the present invention are 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 any of amorphous carbon, graphite-like carbon, crystallized graphite in which the graphite layer has a laminated structure, and 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.

In the present invention, the degree of graphitization of the carbon fine particles is 1.0 or more, preferably 1.2 or more. If the degree of graphitization is too small, for example, electrical conductivity, thermal conductivity and the like are lowered, which is not preferable. The upper limit is not particularly limited, but is usually 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 according to the present invention are also characterized in that the shape thereof is 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. If the sphericity is less than 80, the filling property to the resin or the like deteriorates, 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 a narrow particle size distribution, they exhibit high dispersibility and filling properties in resins and rubbers, and also have a high degree of graphitization, so that resin modifiers, conductive rubbers, It can be suitably used for directionally conductive particles, chromatography carriers, molecular adsorbents, toners, negative electrode materials for lithium ion batteries, catalyst carriers, activated carbon, capacitor electrodes, 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, 99 parts by mass of acrylonitrile and 1 part by mass of itaconic acid were dissolved in 400 parts by mass of dimethyl sulfoxide, 0.5 parts by mass of benzoyl peroxide was added, and the temperature was raised to 70 ° C. Polymerization was performed while maintaining the time to obtain a polyacrylonitrile copolymer solution. The weight average molecular weight of the solution was 530,000. 172 parts by mass of polyvinyl alcohol (“GOHSENOL (registered trademark)” GL-05, weight average molecular weight 10,600, SP value 32.8 (J / cm ³ ) ^1/2 ) manufactured by Nippon Synthetic Chemical Industry Co., Ltd., 2776 parts by mass of dimethyl sulfoxide was added, heated at 80 ° C., and stirred until all the polymers were dissolved. After returning the temperature of the system to room temperature, while stirring at 450 rpm, 1500 parts by mass of ion-exchanged water as a poor solvent is dropped at a speed of 25 parts by mass via a liquid feed pump, and particles are collected. Precipitated. The obtained fine particles were isolated, washed with water, and dried. The number average particle size of the obtained polyacrylonitrile copolymer fine particles was 8.0 μm, the particle size distribution index was 1.30, and the sphericity was 91. A scanning electron micrograph of the obtained fine particles is shown in FIG. The SP value of this polymer was 29.5 (J / cm ³ ) ^1/2 according to the calculation method.

[Production Example 2]
After dissolving 100 parts by mass of acrylonitrile in 400 parts by mass of dimethyl sulfoxide in a reaction vessel equipped with a reflux tube and a stirring blade, 0.5 part by mass of benzoyl peroxide is added, and the mixture is kept at 70 ° C. for 6 hours for polymerization. An acrylonitrile solution was obtained. The weight average molecular weight of the solution was 470,000. 100 parts by mass of polyvinyl alcohol (“GOHSENOL (registered trademark)” GL-05, weight average molecular weight 10,600, SP value 32.8 (J / cm ³ ) ^1/2 ) manufactured by Nippon Synthetic Chemical Industry Co., Ltd., 1400 parts by mass of dimethyl sulfoxide was added, heated at 80 ° C., and stirred until all the polymers were dissolved. After returning the temperature of the system to room temperature, while stirring at 450 rpm, 1500 parts by mass of ion-exchanged water as a poor solvent was added dropwise at a speed of 25 parts by mass via a liquid feed pump, and fine particles were collected. Precipitated. The obtained fine particles were isolated, washed with water, and dried. The number average particle size of the obtained polyacrylonitrile fine particles was 4.6 μm, the particle size distribution index was 1.16, and the sphericity was 96. A scanning electron micrograph of the obtained fine particles is shown in FIG. The SP value of this polymer was 29.5 (J / cm ³ ) ^1/2 according to the calculation method.

[Production Example 3]
In a reaction vessel equipped with a reflux tube and a stirring blade, 99 parts by mass of acrylonitrile and 1 part by mass of itaconic acid were dissolved in 400 parts by mass of dimethyl sulfoxide, 0.5 parts by mass of benzoyl peroxide was added, and the temperature was raised to 70 ° C. Polymerization was performed while maintaining the time to obtain a polyacrylonitrile copolymer solution. The weight average molecular weight of the solution was 530,000. 119 parts by mass of polyvinyl alcohol (“GOHSENOL (registered trademark)” GL-05, weight average molecular weight 10,600, SP value 32.8 (J / cm ³ ) ^1/2 ) manufactured by Nippon Synthetic Chemical Industry Co., Ltd., 1761 parts by mass of dimethyl sulfoxide was added, heated at 80 ° C., and stirred until all the polymers were dissolved. After the temperature of the system was set to 60 ° C., while stirring at 450 rpm, 2380 parts by mass of ion-exchanged water was dropped as a poor solvent via a liquid feed pump at a rate of 20 parts by mass / min, Precipitated. The obtained fine particles were isolated, washed with water, and dried. The resulting polyacrylonitrile copolymer fine particles had a number average particle size of 19.1 μm, a particle size distribution index of 1.38, and a sphericity of 91. The SP value of this polymer was 29.5 (J / cm ³ ) ^1/2 according to the calculation method.

[Production Example 4]
In a reaction vessel equipped with a reflux tube and a stirring blade, 96 parts by mass of acrylonitrile, 3 parts by mass of methacrylic acid, and 1 part by mass of itaconic acid were dissolved in 400 parts by mass of dimethyl sulfoxide, and 0.5 parts by mass of benzoyl peroxide was added. The temperature was raised to 0 ° C. and held for 6 hours for polymerization to obtain a polyacrylonitrile copolymer solution. The weight average molecular weight of the solution was 560,000. 172 parts by mass of polyvinyl alcohol (“GOHSENOL (registered trademark)” GL-05, weight average molecular weight 10,600, SP value 32.8 (J / cm ³ ) ^1/2 ) manufactured by Nippon Synthetic Chemical Industry Co., Ltd., 2776 parts by mass of dimethyl sulfoxide was added, heated at 80 ° C., and stirred until all the polymers were dissolved. After returning the temperature of the system to room temperature, while stirring at 450 rpm, 1500 parts by mass of ion-exchanged water as a poor solvent is dropped at a speed of 25 parts by mass via a liquid feed pump, and particles are collected. Precipitated. The obtained fine particles were isolated, washed with water, and dried. The number average particle size of the obtained polyacrylonitrile copolymer fine particles was 6.7 μm, the particle size distribution index was 1.36, and the sphericity was 88. The SP value of this polymer was 29.5 (J / cm ³ ) ^1/2 according to the calculation method.

[Production Example 5]
In a reaction vessel equipped with a reflux tube and a stirring blade, 95 parts by mass of acrylonitrile, 4 parts by mass of methyl acrylate and 1 part by mass of itaconic acid were dissolved in 400 parts by mass of dimethyl sulfoxide, and 0.5 parts by mass of benzoyl peroxide was added. The temperature was raised to 70 ° C. and held for 6 hours for polymerization to obtain a polyacrylonitrile copolymer solution. The weight average molecular weight of the solution was 490,000. 172 parts by mass of polyvinyl alcohol (“GOHSENOL (registered trademark)” GL-05, weight average molecular weight 10,600, SP value 32.8 (J / cm ³ ) ^1/2 ) manufactured by Nippon Synthetic Chemical Industry Co., Ltd., 2776 parts by mass of dimethyl sulfoxide was added, heated at 80 ° C., and stirred until all the polymers were dissolved. After returning the temperature of the system to room temperature, while stirring at 450 rpm, 1500 parts by mass of ion-exchanged water as a poor solvent is dropped at a speed of 25 parts by mass via a liquid feed pump, and particles are collected. Precipitated. The obtained fine particles were isolated, washed with water, and dried. The number average particle size of the obtained polyacrylonitrile copolymer fine particles was 8.2 μm, the particle size distribution index was 1.40, and the sphericity was 90. The SP value of this polymer was 29.5 (J / cm ³ ) ^1/2 according to the calculation method.

[Example 1]
10.0 g of polyacrylonitrile copolymer fine particles produced in Production Example 1 are placed in a magnetic dish, heated to 250 ° C. in the air in a muffle furnace (FP41, manufactured by Yamato Scientific Co., Ltd.) over 50 minutes, and then 1 hour. Retained. Thereafter, the temperature was raised to 1000 ° C. over 2 hours and 30 minutes under a nitrogen stream to obtain 3.3 g of carbon fine particles. The number average particle size of the obtained carbon fine particles is 5.7 μm, the particle size distribution index is 1.35, the sphericity is 90, and the height ratio (B) / (A) which is an index of the degree of graphitization. Was 1.03. A scanning electron micrograph of the fine particles obtained is shown in FIG.

[Example 2]
10.0 g of polyacrylonitrile copolymer fine particles produced in Production Example 1 are placed in a magnetic dish, heated to 250 ° C. in the air in a muffle furnace (FP41, manufactured by Yamato Scientific Co., Ltd.) over 50 minutes, and then 1 hour. Retained. Thereafter, the temperature was raised to 1300 ° C. over 3 hours and 30 minutes under a nitrogen stream to obtain 2.2 g of carbon fine particles. The obtained carbon fine particles have a number average particle size of 7.1 μm, a particle size distribution index of 1.32, a sphericity of 81, and a height ratio (B) / (A) that is an index of the degree of graphitization. Was 1.07.

[Example 3]
10.0 g of polyacrylonitrile copolymer fine particles produced in Production Example 3 are placed in a magnetic dish, heated in an atmosphere furnace (FP41, manufactured by Yamato Scientific Co., Ltd.) to 250 ° C. over 50 minutes, and then 1 hour. Retained. Thereafter, the temperature was raised to 1000 ° C. over 2 hours and 30 minutes under a nitrogen stream to obtain 5.3 g of carbon fine particles. The obtained carbon fine particles have a number average particle size of 17.7 μm, a particle size distribution index of 1.26, a sphericity of 88, and a height ratio (B) / (A) that is an index of the degree of graphitization. Was 1.00.

[Example 4]
10.0 g of the polyacrylonitrile copolymer fine particles produced in Production Example 4 are placed in a magnetic dish, heated in an atmosphere furnace (FP41, manufactured by Yamato Scientific Co., Ltd.) to 250 ° C. over 50 minutes, and then 1 hour. Retained. Thereafter, the temperature was raised to 1000 ° C. over 2 hours and 30 minutes under a nitrogen stream to obtain 6.1 g of carbon fine particles. The number average particle size of the obtained carbon fine particles is 4.4 μm, the particle size distribution index is 1.41, the sphericity is 86, and the height ratio (B) / (A) that is an index of the degree of graphitization. Was 1.01.

[Example 5]
10.0 g of the polyacrylonitrile copolymer fine particles produced in Production Example 5 are placed in a magnetic dish, heated in an atmosphere furnace (FP41, manufactured by Yamato Scientific Co., Ltd.) to 250 ° C. over 50 minutes, and then 1 hour. Retained. Thereafter, the temperature was raised to 1000 ° C. over 2 hours and 30 minutes under a nitrogen stream to obtain 5.2 g of carbon fine particles. The obtained carbon fine particles have a number average particle size of 6.8 μm, a particle size distribution index of 1.49, a sphericity of 84, and a height ratio (B) / (A) that is an index of the degree of graphitization. Was 1.02.

[Comparative Example 1]
10.0 g of the polyacrylonitrile fine particles prepared in Production Example 2 are placed in a magnetic dish, heated in a muffle furnace (FP41, manufactured by Yamato Kagaku Co., Ltd.) to 250 ° C. at a rate of 5 ° C./min. When held for a period of time, the particles fused together to form aggregates, and the particle diameter and sphericity could not be measured.

[Comparative Example 2]
As a method for producing carbon fine particles from phenol resin fine particles, which is known as a method for firing a carbon fine particle precursor formed by polymerization, carbon fine particles were prepared according to Patent Document 1 (Japanese Patent Laid-Open No. 63-129006). 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. A scanning electron micrograph of the obtained fine particles is shown in FIG.

Claims (9)

Polyolefin copolymers, polyacrylonitrile copolymers composed of copolymers of acrylonitrile monomers and hydrophilic vinyl monomers, polyacrylamide polymers, polyvinyl acetate polymers, polyvinyl chloride polymers Polymer A selected from the group consisting of polymer, polyvinylidene chloride polymer, polyamide, polyarylene ether, polyarylene sulfide, polysulfone, polyetherketone, polyetheretherketone, polyarylate, polyimide, and polymer A In a system in which a polymer B of a different type is mixed with an organic solvent and phase-separated into a solution phase mainly composed of the polymer A and a solution phase mainly composed of the polymer B, after the emulsion is formed, Polymer A is precipitated by bringing the solvent into contact with the polymer. The carbon microparticle preparation method, wherein the produced fine particles, the resulting polymer particles to carbonization. Wherein polymer A method for producing a acrylonitrile based monomer and hydrophilic carbon particles according to claim 1, wherein the vinyl is polyacrylic nitrile-based copolymer comprising a copolymer of monomer. The polyacrylonitrile copolymer comprising a copolymer of an acrylonitrile monomer and a hydrophilic vinyl monomer is more than 0 to 25 parts by weight of the hydrophilic vinyl monomer with respect to 100 parts by weight of the acrylonitrile monomer. The method for producing fine carbon particles according to claim 1, wherein the copolymer is an acrylonitrile copolymer. The carbon fine particle according to any one of claims 1 to 3, wherein the hydrophilic vinyl monomer contains at least one kind of hydroxyl group, carboxyl group, amino group, amide group, sulfonic acid group and phosphoric acid group. Production method. The method for producing carbon fine particles according to any one of claims 1 to 4, wherein the hydrophilic vinyl monomer contains at least one amide group or carboxyl group. 6. The method for producing carbon fine particles according to claim 1, wherein the hydrophilic vinyl monomer is at least one selected from acrylic acid, methacrylic acid, itaconic acid and acrylamide. The method for producing carbon fine particles according to any one of claims 1 to 6, wherein the degree of graphitization of the carbon fine particles is 1.0 or more. The method for producing carbon fine particles according to any one of claims 1 to 7, wherein the number average particle size of the carbon fine particles is 0.1 to 100 µm and the particle size distribution index is 1.0 to 2.0. The number average particle size of the carbon fine particles is 0.1 to 100 μm, the particle size distribution index is 1.0 to 2.0, the graphitization degree is 1.0 or more, and the sphericity is 80 or more. Item 9. A method for producing carbon fine particles according to any one of Items 1 to 8.

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