JP2010024304A - Method for producing electroconductive polymer fine particle, electroconductive polymer fine particle obtained thereby and aqueous dispersion thereof, and circulation system reaction apparatus used in the production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production method by which electroconductive polymer fine particles forming an electroconductive thin film excellent in transparency even in a large film thickness can be efficiently obtained; to further provide a production method by which electroconductive polymer fine particles uniform in particle diameter in spite of fineness can be obtained while regulating or controlling their various properties such as electric properties, and which can meet the demand for mass production of the particles; and to provide electroconductive polymer fine particles obtained by the method, an aqueous dispersion of the particles, and a circulation system reaction apparatus used in the method. <P>SOLUTION: The method for producing electroconductive polymer fine particles includes introducing an electroconductive polymer precursor monomer solution into a passage of a circulation system reaction apparatus, circulating the solution, and subjecting the monomer to oxidation polymerization and microparticulation in the circulation process, wherein a magnetic field is applied to the circulating electroconductive polymer precursor monomer solution. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing conductive polymer fine particles, conductive polymer fine particles obtained thereby, an aqueous dispersion thereof, and a flow reactor used in the production method.

  The transparent conductive film is used for coating of a substrate such as a liquid crystal display, an electroluminescence display, a plasma display, an electrochromic display, a transparent electrode such as a solar cell and a touch panel, and an electromagnetic shielding material. The most widely applied transparent conductive film is a vapor-deposited film of indium-tin composite oxide (ITO). However, there is a problem that a high temperature is required for film formation or the film formation cost is high. The ITO film formed by the coating film formation method also requires a high temperature for film formation, and its conductivity depends on the degree of dispersion of ITO, and the haze value is not necessarily low. Furthermore, an inorganic oxide film such as ITO is likely to crack due to the bending of the base material, and therefore the conductivity tends to decrease. Further, indium is a rare metal and its supply source is limited, and the supply amount may fluctuate or stagnate. Therefore, a next-generation transparent conductive film material replacing ITO is eagerly desired to maintain more stable production of various display devices and the like.

  Polypyrrole and polythiophene, which are conductive polymers, have conductivity even in a fine particle dispersed state and are stable in the air. Conductive paints, rust preventive paints, semiconductor materials, electrolytes for capacitors, hole transport in organic EL devices It is expected to be used for materials, electrode materials, electrode materials for secondary batteries, and the like. A conductive polymer can be generally formed at a low temperature and at a low cost, and it has been proposed to use this as a transparent conductive film in place of an inorganic material such as ITO. However, the conductive polymer material is usually black and powder. Although it is an organic material, it is insoluble in a solvent, and it is difficult to achieve high transparency while maintaining conductivity while being used in a fine particle state.

  By the way, for the purpose of improving the molding processability of polypyrrole, a method for producing an apparently uniform aqueous dispersion by finely dispersing polypyrrole in an aqueous solvent using polyvinyl alcohol (PVA), a surfactant or the like is disclosed. (See Patent Document 1). In addition, a method for producing an aqueous dispersion of polythiophene suitable for an antistatic material by polymerizing in the presence of a polyacid is disclosed (see Patent Document 2). In addition, a method for producing a conductive polymer fine particle dispersion by chemical oxidative polymerization of a monomer that forms a conductive polymer in water in the presence of a reactive emulsifier has been disclosed (see Patent Document 3). However, any of the production methods disclosed above is a polymerization reaction in a batch method using a flask or an electrolytic cell.

  Further, in the case where a monomer or oligomer such as thiophene is electrochemically caused to polymerize on the electrode surface on the surface of the electrode by the monomer and / or oligomer, the reaction is carried out in the presence of a magnetic field of 10 e or more. The manufacturing method of the organic conductor implemented is disclosed (refer patent document 4). Thereby, it is said that anisotropic conductivity can be imparted to the organic conductor. However, this also discloses a method of reacting in an electrolytic cell, and the obtained organic conductor such as polythiophene is in the form of a film and is not a fine particle.

  In addition, there is disclosed a method in which a magnetic field is present in the monomer-containing electrolyte in the channel electrode cell containing the working electrode and the counter electrode, and an electropolymerization reaction is performed in the monomer-containing electrolyte that is caused to flow very gently by the action of the magnetic field. (See Patent Document 5). However, the polymer obtained here is also a film (thin film) and not fine particles.

Japanese Patent Publication No. 7-78116 Japanese Patent Laid-Open No. 7-90060 JP 2007-297500 A JP 7-179576 A JP-A-3-263424

When a conductive thin film is formed from a conventional aqueous dispersion of a conductive polymer, it is difficult to obtain a desired resistance value with a thin film thickness, and usually a film thickness of several tens of μm or more is required to achieve a sufficient resistance value. Met. However, a film having such a thickness may be black with low transparency.
An object of the present invention is to solve the above-mentioned problems and to provide a production method capable of efficiently obtaining conductive polymer fine particles capable of forming a conductive thin film excellent in transparency even when the film thickness is large. And Furthermore, the present invention is a fine conductive polymer fine particle having a uniform particle diameter, and can be obtained by adjusting and controlling each physical property such as its electrical characteristics, and is suitable for this mass production. An object of the present invention is to provide a production method that can be used, and to provide conductive polymer fine particles obtained thereby, an aqueous dispersion thereof, and a flow-type reaction apparatus used therefor.

The above object has been achieved by the following means.
(1) Conductive polymer precursor monomer liquid is introduced into a flow channel of a flow-type reaction apparatus and allowed to flow. In this flow process, the monomer is oxidized and polymerized, and the flow-through conductive polymer precursor is mixed. A method for producing conductive polymer fine particles, which comprises applying a magnetic field to a body monomer liquid.
(2) The method for producing conductive polymer fine particles according to (1), wherein the conductive polymer precursor monomer liquid is an emulsion containing the monomer in a dispersed phase.
(3) The method for producing conductive polymer fine particles according to (1) or (2), wherein the oxidative polymerization is electrolytic oxidative polymerization.
(4) The method for producing conductive polymer fine particles according to any one of (1) to (3), wherein the strength of the applied magnetic field is 0.1 T (tesla) or more.
(5) The flow rate of the conductive polymer precursor monomer liquid is set to 0.1 ml / min or more and 100 ml / min or less, and the conductivity high according to any one of (1) to (4), A method for producing molecular fine particles.
(6) The flow-type reaction device is configured to supply a magnetic field to the liquid flow drive means for flowing the conductive polymer precursor monomer, voltage application means for electrolytic oxidation polymerization of the monomer, and the flow-through monomer liquid. The method for producing conductive polymer fine particles according to any one of (1) to (5), further comprising a magnetic field applying means for applying.
(7) The method for producing conductive polymer fine particles according to any one of (1) to (6), wherein an equivalent diameter of a flow path of the flow reactor is 10 mm or less.
(8) The method for producing conductive polymer fine particles according to any one of (1) to (7), wherein an equivalent diameter of a flow path of the flow reactor is 1 mm or less.
(9) The method for producing conductive polymer fine particles according to any one of (1) to (8), wherein the conductive polymer fine particles are obtained as an aqueous dispersion obtained by dispersing the conductive polymer fine particles in an aqueous medium.
(10) The method for producing conductive polymer fine particles according to any one of (1) to (9), wherein the conductive polymer fine particles are fine particles of polythiophene.
(11) Conductive polymer fine particles produced by the method according to any one of (1) to (10).
(12) An aqueous dispersion containing the conductive polymer fine particles according to (11).
(13) The volume average particle size (MV) of the conductive polymer fine particles is 10 to 70 nm, and the volume average particle size (MV) / number average particle size (MN) is 1.2 to 3.0. (11) or the aqueous dispersion as described in (12) characterized by these.
(14) When the aqueous dispersion is spin-coated on a glass substrate and formed into a thin film having a thickness of 300 nm obtained through a drying step, the transmittance of visible light having a wavelength of 550 nm to the thin film is 95% or more. The aqueous dispersion according to any one of (11) to (13), which is characterized.
(15) When the aqueous dispersion is spin-coated on a glass substrate to obtain a thin film having a thickness of 300 nm obtained through a drying process, the surface resistivity of the thin film at 50% humidity is 1 × 10 ⁴ Ω / The aqueous dispersion according to any one of (11) to (14), wherein
(16) A flow-type reaction apparatus comprising a flow channel for flowing a conductive polymer precursor monomer and generating a conductive polymer obtained by polymerizing the monomer in the flow process as fine particles, wherein the conductive polymer A liquid flow driving means for flowing the precursor monomer liquid in the flow path; a voltage applying means for electrolytic oxidation polymerization of the conductive polymer precursor monomer in the flow state; and a magnetic field applied to the monomer liquid in the flow state. A flow-type reaction apparatus comprising a magnetic field applying means for applying.

According to the production method of the present invention, conductive polymer fine particles having excellent film formability, flexibility, sufficient transparency even when thick, and capable of forming a highly conductive conductive film, It can be obtained efficiently. Further, according to the production method of the present invention, fine conductive polymer fine particles having the same particle size that exhibit the above-mentioned excellent characteristics are prepared by adjusting / controlling each physical property such as its electrical characteristics as necessary. It is possible to cope with the mass production.
The conductive polymer fine particles of the present invention and the aqueous dispersion thereof are transparent conductive materials that form various transparent electrodes such as surface electrodes of electroluminescence panels, pixel electrodes of liquid crystal displays, electrodes of capacitors, and transparent electrodes of touch panels instead of ITO. It can be suitably used as a conductive material and an electromagnetic shielding material for cathode ray tube displays. In addition, low-temperature film formation is possible, and the thin film has flexibility, so that it can be applied to a highly transparent conductive film for plastic films.

The present invention is described in detail below.
In the production method of the present invention, the conductive polymer precursor monomer liquid is introduced and circulated into the flow channel of the flow type reaction apparatus, and the circulates in the flow process when the monomer is oxidized and finely divided. A magnetic field is applied to the conductive polymer precursor monomer solution.

  First, the magnetic field effect in the present invention will be described. In the present invention, it is considered that, for example, the following effects can be expected by performing the electropolymerization in a magnetic field. In general, when a charged particle having a charge (e) moves in a magnetic field having a magnetic flux density (B) at a velocity (V), the Lorentz force (F) is perpendicular to both the direction of the magnetic field and the direction in which the charged particle moves. ) Works. The size is represented by F = eV × B. Such an effect is called a magnetohydrodynamics (MHD) effect, and this effect can be used to control the structure of the polymer. Since a magnetic field is used, there is a possibility that the structure is controlled due to the diamagnetic anisotropy in the molecule, and it is possible that both of these effects act in a complicated manner.

  More specifically, in the present invention, application of a magnetic field can be used to control the growth form and fine structure of conductive polymer fine particles. Thus, physical properties such as thermal properties, electrical conductivity, crystal orientation, and optical properties (transparency) may be affected, and a desired function may be imparted. Regarding preferred embodiments of this magnetic field effect, including an estimation, it is conceivable that the anisotropic effect can sufficiently contribute to the polymerization in the emulsified droplets. Therefore, the effect of promoting polymerization in radical polymerization in the presence of a magnetic field, that is, the effect of stabilizing the radical intermediate and making it difficult to stop polymerization can be expected. Through such an action, according to the present invention, for example, the polymer chain of the conductive polymer can be lengthened, and the conductivity can be further improved while being a nanometer-sized fine particle. Details of the magnetic field applying means will be described later.

  A monomer used as a raw material for the conductive polymer compound used in the production method of the present invention (hereinafter referred to as “conductive polymer precursor monomer”) is selected from the group consisting of thiophene, pyrrole, aniline, and derivatives thereof. At least one selected is preferred. Examples of conductive polymer precursor monomers include thiophene derivatives such as alkylthiophenes (eg, 3-methylthiophene, 3,4-dimethylthiophene, 3-hexylthiophene, 3-stearylthiophene, 3-benzylthiophene, 3-methoxydithiophene). Ethoxymethylthiophene), halogenated thiophene (eg 3-chlorothiophene, 3-bromothiophene), allylthiophene (3-phenylthiophene, 3,4-diphenylthiophene, 3-methyl-4-phenylthiophene), alkoxythiophene (eg 3,4 dimethoxythiophene, 3,4-ethylenedioxythiophene) and the like. Examples of the pyrrole derivative include N-alkylpyrrole (for example, N-methylpyrrole, N-ethylpyrrole, methyl-3-methylpyrrole, N-methyl-3-ethylpyrrole), N-arylpyrrole (for example, N-phenylpyrrole, N -Naphthylpyrrole, N-phenyl-3-methylpyrrole, N-phenyl-3-ethylpyrrole), 3-alkylpyrrole (eg 3-methylpyrrole, 3-ethylpyrrole, 3-n-butylpyrrole), 3-aryl Pyrrole (eg, 3-phenylpyrrole, 3-toluylpyrrole, 3-naphthylpyrrole), 3-alkoxypyrrole (eg, 3-methoxypyrrole, 3-ethoxypyrrole, 3-n-propoxypyrrole, 3-n-butoxypyrrole), 3-aryloxypyrrole (eg 3-phenoxypyrrole) , 3-methylphenoxypyrrole), 3-aminopyrrole (for example, 3-dimethylaminopyrrole, 3-diethylaminopyrrole, 3-diphenylaminopyrrole, 3-methylphenylaminopyrrole, 3-phenylnaphthylaminopyrrole) and the like. It is done. Examples of aniline derivatives include alkyl anilines (eg, o-methyl aniline, m-methyl aniline, o-ethyl aniline, m-ethyl aniline, o-ethoxy aniline, m-butyl aniline, m-hexyl aniline, m-octyl). Aniline, 2,3-dimethylaniline, 2,5-dimethylaniline), alkoxyaniline (eg m-methoxyaniline, 2,5-dimethoxyaniline), aryloxyaniline (eg 3-phenoxyaniline) cyanoaniline (eg o- Cyanoaniline, m-cyanoaniline), halogenated aniline (for example, m-chloroaniline, 2,5-dichloroaniline, 2-bromoaniline, 5-chloro-2-methoxyaniline) and the like. A preferable conductive polymer precursor monomer is a thiophene derivative, and more preferably an alkoxythiophene. Particularly preferred is 3,4-dialkoxythiophene. 3,4-dialkoxythiophene will be described in detail below.

  3,4-dialkoxythiophene used in the method for producing conductive polymer fine particles of the present invention is represented by the following general formula (1).

In the formula, R ¹ and R ² are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, or R ¹ and R ² are bonded to form an alkylene group having 1 to 4 carbon atoms. And the alkylene group may be substituted with any substituent.

In the general formula (1), preferred examples of the alkyl group having 1 to 4 carbon atoms of R ¹ and R ² include a methyl group, an ethyl group, and an n-propyl group. Examples of the alkylene group having 1 to 4 carbon atoms formed by combining R ¹ and R ² include a 1,2-alkylene group and a 1,3-alkylene group, preferably a methylene group, 1, Examples include 2-ethylene group and 1,3-propylene group. Of these, a 1,2-ethylene group is particularly preferred. Moreover, the C1-C4 alkylene group may be substituted, and a C1-C12 alkyl group, a phenyl group, etc. are mentioned as a substituent. Examples of the substituted alkylene group having 1 to 4 carbon atoms include 1,2-cyclohexylene group and 2,3-butylene group.

  The conductive polymer precursor monomer liquid used in the production method of the present invention may be a liquid in which the monomer is uniformly dissolved in a solvent used for the oxidative polymerization reaction, or a dispersion in which a solid monomer is dispersed. It may be a liquid, or may be an emulsion containing the monomer in a continuous layer and / or a dispersed phase. In the present invention, emulsification means that liquid particles (dispersed phase) are dispersed in a liquid (continuous phase) as colloidal particles or coarser particles to form a stable milky dispersion. The conductive polymer precursor monomer liquid of the present invention is preferably an emulsion containing the monomer in the dispersed phase, and particularly preferably used as an emulsion containing water in the continuous phase. The method for preparing the emulsion is not particularly limited, but a method using a homogenizer or a method using a microreactor (micromixer) described later is preferable. In addition to the conductive polymer precursor monomer, the monomer solution may introduce a solvent and / or each additive described later. The concentration of the conductive polymer precursor monomer in the conductive polymer precursor monomer liquid is preferably 0.01 to 100% by mass, more preferably 0.1 to 50% by mass, and particularly preferably 1. It is 0-20 mass%. However, in the case of 80-100 mass%, it is restricted to a liquid monomer.

  The conductive polymer obtained from the conductive polymer precursor monomer of the present invention is a polymer composed of a structural unit represented by the general formula (2) as shown by 3,4-dialkoxythiophene which is a preferred monomer. is there. In addition, since the conductive polymer is insoluble in the solvent, it is difficult to specify the average molecular weight used for defining the physical properties of the polymer by a normal measurement method.

In the formula, R ¹¹ represents R ¹ and R ²² represents the same group as R ² .

The conductive polymer fine particles obtained by the production method of the present invention have a volume average particle size (Mv) measured by a dynamic light scattering method of 10 (particle diameter means the diameter of the particles in the present invention). It is preferably ˜70 nm, more preferably 10 to 50 nm. For monodispersity, the value (Mv / Mn) obtained by dividing the volume average particle size (Mv), which is the index, by the number average particle size (Mn) is used, and the value is 1.2 to 3.0. Is more preferable, and 1.2 to 2.0 is more preferable.
In addition, as a particle diameter measurement method, a microscope method, a dynamic light scattering method, an electric resistance method, or the like can be used. Unless otherwise specified, the particle diameter in the present invention is a value measured by a dynamic light scattering method (device is Nanotrack UPA-EX150 [trade name] manufactured by Nikkiso Co., Ltd.) at a dispersion concentration of 0.2% by mass. .

In the production method of the present invention, the conductive polymer precursor monomer liquid is oxidatively polymerized in the flow process in the flow type reactor, and the oxidative polymerization method will be described in detail below.
As a method of oxidative polymerization in the distribution process, there are chemical oxidation polymerization in which an oxidant is brought into contact with the distribution process for polymerization, and electrolytic oxidation polymerization in which the monomer liquid is passed between the electrodes in the distribution process to be electrically oxidized. Can be mentioned.

First, items common to chemical oxidative polymerization and electrolytic oxidative polymerization will be described.
In the oxidative polymerization in the distribution process of the present invention, an anion may coexist in order to enhance the transparency and conductivity of the obtained fine particle dispersion. In particular, coexistence of polyanions often gives good results. Examples of the polyanion that may coexist include polycarboxylic acids such as polyacrylic acid, polymethacrylic acid, and polymaleic acid, and polysulfonic acids such as polystyrene sulfonic acid and polyvinyl sulfonic acid. Of these, polystyrene sulfonic acid is particularly preferred. These carboxylic acids and sulfonic acids may also be copolymers of vinyl carboxylic acids or vinyl sulfonic acids and other polymerizable monomers (eg, acrylates, styrene, etc.). The number average molecular weight of the polyanion is preferably in the range of 1,000 to 2,000,000, more preferably in the range of 2,000 to 500,000, and particularly preferably in the range of 10,000 to 200,000. preferable. The amount of polyanion used is preferably in the range of 50 to 3,000, more preferably in the range of 100 to 1,000, and particularly preferably in the range of 150 to 500 with respect to 100 parts by weight of the conductive polymer precursor monomer. preferable.

  The solvent used in the oxidative polymerization reaction is not particularly limited as long as it is an inert solvent for the polymerization, but the solvent used in the oxidative polymerization process is preferably a solvent capable of sufficiently dissolving the oxidizing agent in chemical oxidative polymerization. In the oxidative polymerization, a solvent having conductivity is preferable. Specific examples of solvents that can be used for both oxidative polymerizations include alcohol compounds such as methanol, ethanol, 2-propanol, 1-propanol, and ethylene glycol, ketone compounds such as acetone or methyl ethyl ketone, and nitriles such as acetonitrile. Compound solvents, amide compound solvents such as dimethylacetamide or N-methylpyrrolidone, or aqueous media. Among these, an aqueous medium is particularly preferable (in the present invention, the aqueous medium refers to water or a solution obtained by dissolving an organic solvent and / or an acid or a base in water). As the aqueous medium, an aqueous medium mixed with the organic solvent or water is preferable, and water is particularly preferable. When a solvent containing an aqueous medium is used as a medium for a reaction liquid for oxidative polymerization, the resulting conductive polymer fine particle dispersion is obtained as an aqueous dispersion. In the present invention, the aqueous dispersion refers to a dispersion containing an aqueous medium as a main medium, and may contain other components. The conductive polymer fine particles of the present invention are preferably obtained as an aqueous dispersion thereof. At this time, an organic solvent may be added in consideration of the dispersion stability of the fine particles. In the present invention, the content of the conductive polymer fine particles contained in the dispersion is not particularly limited, but is preferably 0.1 to 50% by mass, more preferably 0.5 to 20% by mass. .

  The temperature of the reaction mixture during polymerization is preferably −78 to 100 ° C., more preferably −10 to 60 ° C., particularly preferably 0 to 50 ° C. from the viewpoint of suppressing side reactions, It is particularly preferable that the temperature is 30 ° C.

  Moreover, a dopant can also be introduce | transduced in a polymer by making a doping agent (dopant) coexist in a reaction system in the case of superposition | polymerization. The dopant to be used is not particularly limited as long as it is a commonly used acceptor-type dopant, for example, halogen such as chlorine, bromine and iodine, Lewis acid such as phosphorus pentafluoride, proton acid such as hydrogen chloride and sulfuric acid. Transition metal chlorides such as ferric chloride, and transition metal compounds such as silver perchlorate and silver fluoborate. In addition, a part of the oxidizing agent used for the polymerization may be taken into the polymer and serve as a dopant. The introduction of such a dopant is not essential in the present invention, but the introduction of a dopant can further improve the conductive performance.

  A surfactant may be used as long as the performance of the obtained conductive polymer fine particles is not deteriorated. When a (poly) anion is allowed to coexist as a dopant, it may be used instead of the surfactant. The surfactant is preferably (1) rapidly adsorbed on the surface of the precipitated fine particles to form fine particles, and (2) has an action of preventing these particles from aggregating again. In the present invention, as such a surfactant (dispersant), an anionic, cationic, amphoteric, nonionic or pigmentary low or high molecular dispersant, or high molecular dispersant may be used. it can. These dispersants can be used alone or in combination.

  Anionic dispersants (anionic surfactants) include acylmethyl taurate, fatty acid salts, alkyl sulfate esters, alkylbenzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinates, alkyl phosphate ester salts, naphthalene Examples thereof include sulfonic acid formalin condensate and polyoxyethylene alkyl sulfate ester salt. Of these, acylmethyl taurate is preferred. These anionic dispersants can be used singly or in combination of two or more.

  Cationic dispersants (cationic surfactants) include quaternary ammonium salts, alkoxylated polyamines, aliphatic amine polyglycol ethers, aliphatic amines, diamines and polyamines derived from aliphatic amines and fatty alcohols, fatty acids And imidazolines derived from these and salts of these cationic substances. These cationic dispersants can be used singly or in combination of two or more.

  An amphoteric dispersant (a zwitterionic surfactant) is a dispersant having both an anion group part in the molecule of the anionic dispersant and a cation group part in the molecule of the cationic dispersant. is there.

  Nonionic dispersants (nonionic surfactants) include polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylamine, Examples thereof include glycerin fatty acid esters. Of these, polyoxyethylene alkylaryl ether is preferable. These nonionic dispersants can be used singly or in combination of two or more.

Next, chemical oxidative polymerization will be described.
The oxidizing agent used for chemical oxidative polymerization in this embodiment is not particularly limited as long as it has the ability to sufficiently oxidize monomers in the flow process, but preferably peroxodisulfuric acid, sodium peroxodisulfate, potassium peroxodisulfate, Examples thereof include ammonium peroxodisulfate, inorganic ferric oxide salt, organic ferric oxide salt, hydrogen peroxide, peracetic acid, potassium permanganate, cerium sulfate, potassium dichromate, alkali perborate, and copper salt. Particularly preferred are peroxodisulfuric acid, sodium peroxodisulfate, potassium peroxodisulfate, and ammonium peroxodisulfate. Further, a catalytic amount of metal ions such as iron, cobalt, nickel, molybdenum, vanadium ions may be added as a co-oxidant (mediator). The amount of the oxidizing agent used is preferably in the range of 1 to 5 equivalents, more preferably in the range of 2 to 4 equivalents, per mole of the conductive polymer precursor monomer. The reaction temperature may be appropriately adjusted depending on the monomer used, the type and amount of the oxidizing agent, etc., but it is preferably -78 to 100 ° C, more preferably -10 to 60 ° C.

Next, electrolytic oxidation polymerization will be described.
The electrolytic oxidation polymerization can be carried out in the presence or absence of a solvent that is inert under electrolytic conditions, and is preferably carried out in the presence of an inert solvent. Moreover, you may add a predetermined additive to a solvent. Examples of the additive used for electrolytic oxidation polymerization include an electrolyte compound and a mediator (auxiliary agent).

  The electrolyte compound preferably used is a free acid having a certain degree of solubility in the solvent used or a salt having a standard conductivity. Suitable compounds as electrolyte compounds include, for example, p-toluenesulfonic acid, methanesulfonic acid as free acids, and alkyl sulfonates, aryl sulfonates, tetrafluorofolates, hexafluorophosphates, perchlorates as salts Acid salts, hexafluoroantimonate, hexafluoroarsenate, and hexachloroantimonate and alkali metals, alkaline earth metals, or optionally alkylated ammonium, phosphonium, sulfonium, and oxonium chaotene.

  The electrolyte compound is preferably used in an amount necessary for a current of at least 0.1 mA to flow during electrolysis. The concentration of the conductive polymer precursor monomer in the conductive polymer precursor monomer liquid during electrolytic oxidation polymerization is not particularly limited, but is preferably 0.01 to 100% by mass, and 0.05 to 20% by mass. % Is more preferable. 100 mass% is a case of a liquid monomer.

  In the electrolytic oxidation polymerization, it is preferable that a mediator (co-oxidant) that mediates electron transfer between the reaction substrate (monomer or oligomer) and the electrode coexists. Examples of mediators include organic, inorganic, and metal mediators, with organic or inorganic mediators being preferred. Specifically, organic mediators such as an N-oxyl compound of 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) and inorganic mediators such as iron chloride.

The electrolytic oxidation polymerization can be carried out discontinuously or continuously. Examples of a material suitable as an electrode material when applying a voltage to cause an electrolytic oxidation polymerization reaction include noble metals and steel. Specifically, a platinum sheet, a steel plate, a noble metal and a steel net, a carbon black filled polymer, a metal vapor-deposited insulating layer, a carbon felt, and the like. In addition, an electrode coated with a swellable polymer film (for example, a polyvinyl chloride film) can be used. The current density of the electrolytic oxidation polymerization can be varied over a wide range, the current density is preferably ^{0.0001~100mA / cm 2, 0.01~40mA / cm} 2 is more preferable. The voltage at such a current density is preferably about 0.1 to 50V, more preferably 0.5 to 30V. The reaction temperature during the electrolytic oxidation polymerization is preferably 0 to 100 ° C, more preferably 0 to 50 ° C, and particularly preferably 0 to 30 ° C from the viewpoint of suppressing side reactions.

  Regarding the electrolytic oxidation polymerization method, the descriptions in JP-A Nos. 61-8344, 63-137925 and 1-313521 can be referred to.

  In the production method of the present invention, the conductive polymer precursor monomer liquid is oxidatively polymerized in the flow process in the flow reactor, and the flow process in the flow reactor will be described in detail below. By conducting the oxidative polymerization in the flow process, the polymerization reaction can be performed under uniform conditions as compared with the batch method in which the oxidative polymerization of the conductive polymer precursor monomer is performed in the reaction kettle. In addition, in the case of electrolytic oxidation polymerization, the batch method using a flask or an electrolytic bath is difficult to obtain as desired fine particles because the conductive polymer is obtained as a film deposited on the electrode.

  In the present invention, it is preferable to perform oxidative polymerization in a flow process in a process under laminar flow or in a transient state located between laminar flow and turbulent flow. Laminar flow and turbulent flow are described as follows. When water is poured into the tube, a thin tube is inserted into its central axis and colored liquid is injected, the colored liquid flows as a single line while the flow rate of water is low, and the water flows on the tube wall. It flows straight in parallel. However, when the flow velocity is increased and reaches a certain flow velocity, the water flow suddenly becomes turbulent, and the colored liquid is mixed with the water flow to become a colored flow. The former flow is called laminar flow, and the latter flow is called turbulent flow. This is called a transient flow.

Whether the flow becomes laminar or turbulent depends on whether or not the Reynolds number, which is a dimensionless number indicating the state of the flow, is below a certain critical value. The smaller the Reynolds number, the easier it is to form a laminar flow. The Reynolds number Re of the flow in the pipe is expressed by the following equation.
Re = D <υ _x > ρ / μ
D is the equivalent diameter of the tube, <υ _x > is the average cross-sectional velocity, ρ is the density of the fluid, and μ is the viscosity of the fluid. As can be seen from this equation, the smaller the equivalent diameter, the smaller the Reynolds number. Therefore, in the case of an equivalent diameter of μm, it becomes easy to form a stable laminar flow. It can also be seen that the liquid physical properties of density and viscosity also affect the Reynolds number, and the smaller the density and the greater the viscosity, the smaller the Reynolds number and the more easily the laminar flow is formed.

The critical Reynolds number at which the flow changes is called the critical Reynolds number. The critical Reynolds number is not always constant, but the next value is the standard. (Edited by Fumimaru Kanno, “Chemical Engineering Handbook”, p. 37, 2004, Asakura Shoten)
Re <2300 laminar flow
Re> 4000 Turbulence 4000 ≧ Re ≧ 2300 Transient state (transition region)

  Examples of transient flows include Karman vortices and Taylor vortices that include flows from the laminar vortex region to the turbulent region (“Chemical Engineering Handbook 6th revised edition, Chemical Engineering Society, Maruzen Co., Ltd.”, “ RIKEN Dictionary 5th edition, Iwanami Shoten ”,“ M. Engler et al., “Effective Mixing by the Use of Conventional Micro Mixers”, Conference Proceedings, 2005 Spring 304, National IC, et al. reference).

  By forming fine particles in the flow process of laminar flow or transient state (Re <4000) and controlling the growth rate of the particles, a fine particle dispersion having a small particle size and a narrow distribution can be efficiently prepared. . The conductive polymer fine particle precipitation by oxidative polymerization in the distribution process is particularly preferable in view of excellent particle size, distribution and dispersion stability and high production efficiency. In particular, fine particles having a narrow particle size distribution (excelling in monodispersity) are preferable for forming a thin film having excellent transparency.

  In the production method of the present invention, a preferred flow reactor is a device having an equivalent diameter of a flow path of 10 mm or less, particularly preferably a device having an equivalent diameter of 1 mm or less. The flow-type reaction apparatus having an equivalent diameter of 1 mm or less in the flow path is generally called “microreactor” and has been greatly developed recently. A typical microreactor includes a plurality of microchannels (the above-described reaction apparatus) having an equivalent diameter of several μm to several hundreds of μm when the cross section is converted into a circle, and a mixing space connected to these microchannels. In this microreactor, by introducing a plurality of solutions into the mixing space through a plurality of microchannels, a plurality of solutions can be mixed, or a chemical reaction can be caused together with the mixing.

  Next, the difference between the reaction by the microreactor as described above and the batch method using a tank or the like will be described. That is, in the chemical reaction between the liquid phases, the reaction generally occurs when molecules meet at the interface of the reaction solution. Therefore, when the reaction is performed in a microspace (microchannel), the area of the interface becomes relatively large, The reaction efficiency increases significantly. In addition, as described above, the diffusion time of the molecule itself is proportional to the square of the distance. This means that as the scale is reduced, the reaction proceeds more easily by the diffusion of molecules in the circulation region without active mixing of the reaction solution. Also, in the micro space, since the scale is small, the flow is dominated by laminar flow, and the solutions are in a laminar flow state and are diffused and mixed with each other.

  By using the microreactor having the above-described features, it is possible to precisely control the reaction time and temperature between solutions as compared with the conventional batch system using a large volume tank or the like as a reaction field. In the case of the batch method, the reaction proceeds at the reaction contact surface at the initial stage of mixing, particularly between solutions with a high reaction rate, and the primary product generated by the reaction between the solutions continues to be reacted in the vessel. As a result, the product may become non-uniform or agglomeration or precipitation may occur in the mixing container. On the other hand, according to the microreactor, the solution continuously circulates with almost no stagnation in the mixing container. Therefore, while the primary product generated by the reaction between the solutions stays in the mixing container, it continues. It is possible to suppress the reaction, and it is possible to take out a pure primary product that has been difficult to remove in the past.

  In addition, when a small amount of chemical substances produced by an experimental production facility is manufactured (scaled up) in a large amount by a large-scale production facility, a large-scale batch method is conventionally used. It took a great deal of labor and time to obtain reproducibility at the production facility, but this reproducibility can be achieved by parallelizing production lines using microrear coolers according to the required production volume. The labor and time for obtaining the potential can be greatly reduced. The microreactor can be produced by a normal method, for example, refer to paragraphs [0035] to [0040] of JP-A-2005-307154.

  The equivalent diameter of the flow path in the apparatus used in the production method of the present invention is preferably 10 mm or less, more preferably 1 mm or less, further preferably 10 μm to 1 mm, and more preferably 20 to 500 μm. Particularly preferred. The length of the channel is not particularly limited, but is preferably 1 mm or more and 10 m or less, more preferably 5 mm or more and 10 m or less, and particularly preferably 10 mm or more and 5 m or less. Regarding microreactors, there have been reports on devices aimed at improving reaction efficiency. For example, Japanese Patent Application Laid-Open Nos. 2003-210960, 2003-210963, and 2003-210959 describe micromixers, and these microdevices can also be used.

  In order to introduce and circulate a predetermined liquid into the flow path, it is preferable to use a liquid flow driving means, and more preferably to use a fluid control means. In particular, since the behavior of the fluid in the microchannel has a property different from that of the macroscale, it is preferable to employ a control method suitable for the microscale. The liquid drive system is classified into a continuous flow system and a droplet (liquid plug) system when classified into forms, and an electrical drive system and a pressure drive system when classified into drive forces. For further details on these methods, reference can be made to paragraphs [0041] to [0046] of JP-A-2005-307154, for example.

  In the production method of the present invention, the velocity (flow rate) of the fluid flowing in the flow path is preferably 0.002 ml to 5000 ml / min, including chemical oxidative polymerization and electrolytic oxidative polymerization, and is 0.003 ml to 500 ml / min. More preferably, it is more preferably 0.01 ml to 250 ml / min, and particularly preferably 0.1 ml to 100 ml / min.

  In the production method of the present invention, by obtaining conductive polymer fine particles in a flow-type reaction apparatus, fine particles having a uniform particle size that cannot be obtained by forming particles in a flask can be obtained. Further, if this flow reactor is numbered up (in parallel), it is possible to produce a large amount of fine particles and an organic solvent dispersion thereof with high reproducibility.

  As an embodiment of a reaction apparatus suitably used when the oxidative polymerization in the present invention is carried out by electrolytic oxidation, an electrolytic oxidation apparatus having electrodes on the side surfaces of a flow path is schematically shown in FIGS. 2 is a cross-sectional view showing a cross section taken along line II-II of FIG. 1, and FIG. 3 is a cross-sectional view showing a cross section taken along line III-III of FIG. Needless to say, the present invention is not limited to these examples. In the apparatus of the present embodiment, only one flow path is shown. However, as described above, a plurality of flow paths may be provided, and the flow path is divided into two or more before reaching the inlet 111. Alternatively, a multi-liquid mixing type reaction apparatus in which multiple liquids are combined may be adapted to support chemical oxidative polymerization. At this time, it is preferable that the magnetic field is applied after the mixed region where multiple liquids join, but the magnetic field may be applied to the entire apparatus. In addition, the magnetic pole 115 for applying the magnetic field is not shown in the illustrated configuration on both sides of the electrode 114, but may be configured in such a manner that the magnetic pole is provided on the upper and lower sides of the electrode opposite to the flow path of the electrode 114. In this case, the magnetic flux generation direction of the magnetic field (magnetic field) and the current generation direction of the electric field (electric field) coincide with each other, and an electric field and a magnetic field parallel to each other are generated. The above arrangement of the electrode and the magnetic pole is a preferable arrangement, but the arrangement relationship is not limited to these, and the arrangement relationship is not particularly limited as long as it works most efficiently.

  In the apparatus 100 of this embodiment, reference numeral 114 denotes a platinum vapor deposition electrode. In the present embodiment, a power source, a conducting wire, a terminal, an electrode, and the like can be used as the voltage applying means, but only the electrode portion of the reaction apparatus is illustrated. The apparatus 100 has an introduction port 111, a discharge port 112, and a flow path 113, and the shape of the cross section perpendicular to the length direction of the flow path 113 can be finely processed as necessary, but in a shape close to a trapezoid or a rectangle. Preferably there is. If the channel width W and the channel depth H are set to the micrometer size, heating and cooling can be performed instantaneously. The monomer liquid introduced from the introduction port 111 is converted into a polymer fine particle dispersion by electrolytic oxidation polymerization in the process of flowing through the range indicated by the flow path length a containing the electrode. Magnetic field applying means 115 is arranged on both sides of the electrode 114. Therefore, an electric field (electric field) is generated between the upper electrode 114a and the lower electrode 114b. In contrast, a magnetic field (magnetic field) is generated between the left magnetic pole 115a and the right magnetic pole 115b. Thus, in this embodiment, the direction of the magnetic flux in the magnetic field (magnetic field) is orthogonal to the direction of the current in the electric field (electric field).

  In the manufacturing method of the present invention, any magnetic field applying means may be used as long as it has a magnetic pole capable of generating a magnetic field. For example, a permanent magnet, an electromagnet, a superconducting magnet, or a hybrid magnet is used. In addition, both a stationary magnetic field and a pulsed magnetic field can be used. In general, the magnetic strength is expressed by magnetic flux density (unit: T (Tesla), 1T = 10,000 Oe (Oersted)). The permanent magnet can cover 1.5T or less, and the iron magnet electromagnet can cover up to about 2T. It is said. Superconducting magnets (currently possible up to about 15T) and hybrid magnets (currently possible up to about 30T) can be used to achieve more. The magnetic field used in the present invention is preferably 0.01T to 10T, and more preferably 0.01T to 5T.

[Transmissivity]
A feature of the conductive polymer fine particle dispersion of the present invention is that a thin film produced using the same has a high transmittance and is transparent. In the present invention, unless otherwise specified, the thin film is formed on a quartz glass substrate by spin coating so as to have a thickness of about 300 nm after drying, and the thin film coating obtained through the drying step is performed. The glass plate refers to a transmittance value of 550 nm measured by a spectrophotometer (MPC-2200 manufactured by Shimadzu Corporation) with a base quartz glass substrate as a reference.

  The thin film on the glass substrate is manufactured to a thickness of about 300 nm through a spin coating / drying process. However, considering the thickness variation, the thickness of the thin film produced is measured using a stylus type step gauge (ULVAC, DEKTAK 6M [trade name]), and the transmittance at a thickness of 300 nm is calculated from the measured value. (Transmissivity is proportional to film thickness). The visible light transmittance (T) at a wavelength of 550 nm of the 300 nm-thick film on the glass substrate by the dispersion of the present invention thus obtained is 90% or more, preferably 95% or more. The film having a level of 95% or more is a film having a high level of transparency that can be applied to an image display device in the state of the art.

  The drying temperature in the case of applying and drying the dispersion of the present invention on a substrate is preferably 20 to 250 ° C, more preferably 50 to 130 ° C. The drying time is preferably 3 seconds to 1 week, more preferably 5 seconds to 60 seconds. In this way, a coated substrate having a transparent conductive film having the conductive polymer fine particles of the present invention is obtained. The thin film on the surface of the obtained substrate has flexibility, and particularly exhibits high transparency while having sufficient conductivity as compared with conventional thin films made of polythiophene-based conductive polymer dispersions. can do.

[Surface resistivity]
In the present invention, the conductivity of the film containing the conductive polymer fine particles is expressed by a manifest resistivity (unit Ω / □). Unless otherwise specified, the measurement refers to a value measured under a humidity of 50% by Loresta-EP MCP-T360 (trade name) manufactured by Mitsubishi Chemical. The surface resistivity is preferably in the range of 1 × 10 ² to 1 × 10 ⁷ Ω / □, and more preferably in the range of 1 × 10 ² to 1 × 10 ⁵ Ω / □.

  The transparent conductive film produced using the dispersion liquid of the conductive polymer fine particles of the present invention is a transparent electrode such as a surface electrode of an electroluminescence panel, a pixel electrode of a liquid crystal display, a capacitor electrode, a transparent electrode of a touch panel, and a cathode ray tube. It is suitably used for electromagnetic shielding of displays.

  The present invention will be described below in more detail based on examples, but the present invention is not limited to these examples. In the following examples and comparative examples, volume average particle diameter Mv, number average particle diameter Mn, transmittance measurement, and surface resistivity measurement were performed as follows.

[Measurement of Volume Average Particle Size (Mv) and Number Average Particle Size (Mn)]
4. After purifying the dispersion sample with an ultrafiltration device (Advantech Toyo Co., Ltd., UHP-62K (trade name), molecular weight cut off 50,000) while adding distilled water to eliminate the filtrate and keeping the volume constant, Concentrated to 0% by weight. The volume average particle diameter of the liquid particles and the volume average particle diameter Mv / number average particle diameter Mn, which is an index of monodispersibility, were measured. The particle size (Mv) and monodispersity (Mv / Mn) of the particles were diluted with distilled water to a fine particle concentration of 0.2% by mass using Nanotrac UPA-EX150 (trade name) manufactured by Nikkiso Co., Ltd. It measured at room temperature (about 25 degreeC).

[Measurement of transmittance]
A 5.0 mass% concentrated solution of the dispersion sample was spin-coated on the above glass substrate (using 1KA-PX2 [trade name] manufactured by MIKASA), dried at 70 ° C. for 60 minutes, and 300 nm A conductive polymer fine particle film was prepared so as to have a thickness. The film pressure of the obtained film sample was measured using a stylus type step gauge (manufactured by ULVAC, DEKTAK 6M [trade name]) (at this time, the error was corrected by the film thickness, and the transmittance at a thickness of 300 nm was measured. Value was calculated).

[Measurement of surface resistivity]
The surface resistivity of a film sample produced in the same manner as the above transmittance measurement was measured using a Loresta EP MCP-T360 (trade name) manufactured by Mitsubishi Chemical Corporation at a humidity of 50%.

Example 1
Conductive polymer precursor monomer (3,4-ethylenedioxythiophene) 14 g (0.1 mol), polystyrene sulfonic acid (mass average molecular weight 4,000) 18 g (0.1 mol SO ₃ H) anionic surface activity 2 g of the agent (Aqualon KH-10, trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 300 g of water were vigorously stirred and mixed (a homogenizer was used. The rotation speed was 5000 rpm for 1 minute). The prepared emulsion was designated as IA liquid.

  As the reaction apparatus shown in FIG. 1, a ceramic apparatus 100 having a flow path equivalent diameter of 300 μm was prepared. Two Teflon (registered trademark) tubes were connected to the inlet 111 using a connector with a check valve, and a syringe containing the IA solution was connected to the tip of the tube and set in a pump. A connector having a pressure control valve was connected to the discharge port 112, and a Teflon (registered trademark) tube was connected thereto.

  The size of the apparatus main body was 20 cm (length) × 2 cm (width) × 1 cm (thickness). The platinum electrodes 114 and 115 were respectively disposed above and below the flow path 113 over 10 cm (length a). They were connected to the potentiostat by wiring. The reaction temperature was adjusted to about 50 ° C. (At this time, a Peltier element cooling device was used), and a constant current of 22 mA (voltage was 6 to 7 V) was applied to the flowing IA liquid to carry out an electrolytic oxidation polymerization reaction. The magnetic field applying means 115 was manufactured using a permanent magnet device (permanent magnet lanternette [trade name] manufactured by NEC Tokin Corporation), and generated a magnetic field having a strength of 0.5 T.

  As a mediator, 1.4 g of 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) was mixed with the IA solution prepared under the above conditions, and the solution was introduced from the inlet 111 at a flow rate of 20 μL / min. When injected, a dispersion liquid of conductive polymer fine particles was obtained from the discharge port 112. The injection was continued for 1 hour, and the dispersion was collected from the tip of the tube. The particle size and monodispersity, transmittance, and surface resistivity of the obtained dispersion (Sample 1) were measured. The results are shown in Table 1 below.

(Example 2)
A dispersion of conductive polymer fine particles was obtained in the same manner as in Example 1, except that the conductive polymer precursor monomer of the IA liquid was replaced with pyrrole in an equimolar amount, and the mediator was changed to iron (II) chloride. . The particle diameter and monodispersity, transmittance, and surface resistivity of the fine particles in the obtained dispersion (Sample 2) were measured. The results are shown in Table 1 below.

(Example 3)
In the same manner as in Example 2, except that the magnetic field strength was set to 1.0 T using an electromagnet device (manufactured by NEC TOKIN Corporation, electromagnet SEE-2 [trade name] for variable magnetic pole gap experiment). A dispersion of fine particles was obtained. The particle size and monodispersity, transmittance, and surface resistivity of the obtained dispersion (sample 3) were measured. The results are shown in Table 1 below.

Example 4
In the same manner as in Example 1, except that the magnetic field strength was changed to 1.2 T using an electromagnet device (manufactured by NEC Tokin Co., Ltd., electromagnet SEE-2 for variable magnetic pole gap experiment). A liquid was obtained. The particle size and monodispersity, transmittance, and surface resistivity of the obtained dispersion (sample 4) were measured. The results are shown in Table 1 below.

(Example 5)
The apparatus was replaced with the apparatus of Example 4, and the apparatus which installed the magnetic field application means 115 so that it might each be located in the electrode outer side on the opposite side to a flow path with respect to the electrode 114 was used. A 1.2T magnetic field is applied here using an electromagnet device (NEC Tokin Co., Ltd. magnetic pole gap variable experiment electromagnet SEE-2), and a magnetic field in the same (parallel) direction as the electric field is generated. A dispersion sample was prepared. The particle size and monodispersity, transmittance, and surface resistivity of the obtained dispersion (sample 5) were measured. The results are shown in Table 1 below.

(Example 6)
A dispersion of conductive polymer fine particles was obtained in the same manner as in Example 1 except that the conductive polymer precursor monomer of the IA liquid was replaced with an equimolar amount of aniline. The particle size and monodispersity, transmittance, and surface resistivity of the obtained dispersion (sample 6) were measured. The results are shown in Table 1 below.

(Example 7)
A dispersion liquid of conductive polymer fine particles was obtained in the same manner as in Example 1 except that the equivalent diameter of the flow path was changed to 150 μm and the magnetic field strength was changed to 2T. The particle size and monodispersity, transmittance, and surface resistivity of the obtained dispersion (sample 7) were measured. The results are shown in Table 1 below.

(Example 8)
In the same manner as in Example 7, except that the equivalent diameter of the flow path was changed to 500 μm and the magnetic field strength was changed to 10 T using a superconducting magnet device (HF10-100VHT [trade name] manufactured by Sumitomo Heavy Industries, Ltd.). As a result, a dispersion of conductive polymer fine particles was obtained. However, the apparatus used was the same as in Example 5, and the apparatus in which the magnetic field was in the same direction as the electric field. The particle diameter and monodispersity, transmittance, and surface resistivity of the obtained dispersion (sample 8) were measured. The results are shown in Table 1 below.

Example 9
The IA solution was prepared. However, no mediator was used here. Separately from this, a solution prepared by dissolving 108 g (0.4 mol) of ammonium persulfate as an oxidizing agent in 600 g of water was designated as IIA solution. As a microreactor, an apparatus having a T-shaped channel having two inlets and two forks for the one shown in FIGS. In this apparatus, the magnetic field applying means is installed after the point where the liquid introduced and circulated from the introduction port joins, and is arranged so that the magnetic field is generated so as to be orthogonal to the flow path surface. The magnetic field strength was set to 0.5 T with a permanent magnet device (manufactured using a permanent magnet lanternette manufactured by NEC TOKIN Corporation). The equivalent diameter of the merged portion and the subsequent flow path was 10 mm. The electrodes were not arranged because no voltage was applied.

  In the state where 6m length (1m to 7m point from the outlet) of the Teflon (registered trademark) tube connected to the connector outlet using the above microreactor is immersed in an oil bath maintained at a temperature of 70 ° C, the IA liquid Was delivered at a delivery rate of 10 mL / min and the IIA solution at a delivery rate of 20 mL / min. Since the conductive polymer fine particle dispersion was obtained, it was collected. The volume average particle diameter of the particles of this dispersion (sample 9), volume average particle diameter Mv / number average particle diameter, which is an index of monodispersibility, transmittance, and surface resistivity were measured.

(Example 10)
A dispersion of conductive polymer fine particles was obtained in the same manner as in Example 9, except that the equivalent diameter of the flow path was 1 mm. In addition, in order to make the residence time in the microchannel 23 after joining the same, the liquid feed rate of the IA liquid was 0.3 ml / min, and the liquid feed speed of the IIA liquid was 0.6 ml / min. The volume average particle diameter of the particles of this dispersion (sample 10), volume average particle diameter Mv / number average particle diameter, which is an index of monodispersibility, transmittance, and surface resistivity were measured.

(Example 11)
Under the same conditions as in Example 9, except that the equivalent diameter of the flow path was changed to 300 μm, a dispersion of conductive polymer fine particles was obtained. The volume average particle diameter of the particles of this dispersion (sample 11), volume average particle diameter Mv / number average particle diameter, which is an index of monodispersibility, transmittance, and surface resistivity were measured.

(Reference example)
A dispersion sample was prepared in the same manner as in each of the above examples, except that no magnetic field was applied. The particle size, monodispersity, transmittance, and surface resistivity of the fine particles of the obtained dispersion (samples 12 to 22) were measured. The results are shown in Table 1.

[Table 1]
------------------------------------
Sample No. Mv (nm) Mv / Mn transmittance Surface resistivity
(Volume average diameter) (Monodispersity) (%) (Ω / □)
------------------------------------
1 27.5 1.20 98.8 1.3 × 10 ³
2 35.5 1.50 98.0 1.5 × 10 ⁴
3 25.5 1.20 98.8 7.0 × 10 ³
4 24.3 1.19 99.0 9.8 × 10 ²
5 28.0 1.22 98.5 1.5 × 10 ³
6 39.0 1.60 96.6 1.8 × 10 ⁵
7 18.5 1.19 99.6 8.8 × 10 ²
8 17.5 1.15 99.8 2.5 × 10 ²
9 55.0 2.60 92.0 9.5 × 10 ⁷
10 40.1 1.90 94.5 7.5 × 10 ⁶
11 35.4 1.65 96.6 2.5 × 10 ⁵
12 30.5 1.22 98.3 1.2 × 10 ⁴
13 40.3 1.55 97.2 2.0 × 10 ⁵
14 30.0 1.35 97.5 8.5 × 10 ⁴
15 27.7 1.22 98.6 1.5 × 10 ³
16 31.1 1.25 98.0 1.3 × 10 ⁴
17 45.5 1.72 95.5 2.0 × 10 ⁶
18 20.3 1.23 99.5 1.2 × 10 ⁴
19 20.4 1.22 99.4 1.3 × 10 ⁴
20 69.0 2.80 90.5 8.1 × 10 ⁸
21 45.5 2.05 92.3 5.3 × 10 ⁷
22 40.3 1.83 95.3 1.2 × 10 ⁶
------------------------------------

(Comparative example)
The conductive polymer precursor monomer liquid (IA liquid) used in Example 1 is put in a flask, a pair of platinum electrodes is introduced into the liquid, and a voltage is applied for 2 hours so that a constant current of 22 mA flows. Electrolytic oxidation polymerization was performed. As a result, the conductive polymer film adhered to the electrode and fine particles were not obtained.

From the above results, it can be seen that according to the production method of the present invention, a dispersion of conductive polymer fine particles having a nanometer size and a uniform particle diameter can be obtained efficiently. Moreover, the thin film formed using the dispersion liquid has electroconductivity and high transparency.
From the above results, the conductive polymer fine particle dispersion obtained by the production method of the present invention can form an industrially useful conductive thin film that maintains high transparency even with a thick film. I understand that. Furthermore, according to the present invention, it can be seen that the nanomail-sized fine particles can be further refined by applying a magnetic field, and the particle diameters can be further aligned. Moreover, it turns out that physical properties, such as an electrical property, of the electroconductive polymer fine particle obtained can be changed by changing the magnetic field strength to apply.

  On the other hand, in the electrolytic oxidation polymerization method using a flask (Comparative Example), the conductive polymer compound could not even be obtained as fine particles.

It is a top view which shows typically preferable embodiment of the flow-type reaction apparatus used for the manufacturing method of this invention. It is sectional drawing which shows the II-II line cross section of the flow-type reaction apparatus of FIG. It is sectional drawing which shows the III-III line cross section of the flow-type reaction apparatus of FIG.

Explanation of symbols

110 reactor main body 111 introduction port 112 discharge port 113 flow path 114 voltage application means (platinum vapor deposition electrode)
115 Magnetic field applying means

Claims (16)

  When the conductive polymer precursor monomer liquid is introduced into the flow channel of the flow-type reaction apparatus and circulated, the flow-through conductive polymer precursor monomer liquid described above is oxidized and polymerized in this flow process. A method for producing conductive polymer fine particles, wherein a magnetic field is applied to the substrate.   The method for producing conductive polymer fine particles according to claim 1, wherein the conductive polymer precursor monomer liquid is an emulsion containing the monomer in a dispersed phase.   The method for producing conductive polymer fine particles according to claim 1, wherein the oxidative polymerization is electrolytic oxidative polymerization.   The method for producing conductive polymer fine particles according to any one of claims 1 to 3, wherein the strength of the applied magnetic field is 0.1 T (Tesla) or more.   The method for producing conductive polymer fine particles according to any one of claims 1 to 4, wherein the flow rate of the conductive polymer precursor monomer liquid is 0.1 ml / min or more and 100 ml / min or less. .   The flow type reaction device has a liquid flow drive means for flowing the conductive polymer precursor monomer, a voltage applying means for electrolytic oxidation polymerization of the monomer, and a magnetic field for applying a magnetic field to the flowed monomer liquid. The method for producing conductive polymer fine particles according to claim 1, further comprising an applying unit.   The method for producing conductive polymer fine particles according to any one of claims 1 to 6, wherein the flow path of the flow reaction apparatus has an equivalent diameter of 10 mm or less.   The method for producing conductive polymer fine particles according to any one of claims 1 to 7, wherein an equivalent diameter of a flow path of the flow reactor is 1 mm or less.   The method for producing conductive polymer fine particles according to any one of claims 1 to 8, which is obtained as an aqueous dispersion in which the conductive polymer fine particles are dispersed in an aqueous medium.   The method for producing conductive polymer fine particles according to claim 1, wherein the conductive polymer fine particles are polythiophene fine particles.   Conductive polymer fine particles produced by the method according to any one of claims 1 to 10.   An aqueous dispersion containing the conductive polymer fine particles according to claim 11.   The conductive polymer fine particles have a volume average particle size (MV) of 10 to 70 nm and a volume average particle size (MV) / number average particle size (MN) of 1.2 to 3.0. The aqueous dispersion according to claim 11 or 12.   When the aqueous dispersion is spin-coated on a glass substrate to form a thin film having a thickness of 300 nm obtained through a drying step, the visible light transmittance at a wavelength of 550 nm to the thin film is 95% or more. The aqueous dispersion according to any one of claims 11 to 13. When the aqueous dispersion is spin-coated on a glass substrate to obtain a thin film having a thickness of 300 nm obtained through a drying process, the surface resistivity under a humidity of 50% is 1 × 10 ⁴ Ω / □ or less. The aqueous dispersion according to claim 11, wherein the aqueous dispersion is.   A flow-type reaction apparatus comprising a flow path for flowing a conductive polymer precursor monomer and generating a conductive polymer obtained by polymerizing the monomer in the flow process as fine particles, the conductive polymer precursor monomer A liquid flow driving means for flowing a liquid in the flow path, a voltage applying means for electrolytic oxidation polymerization of the conductive polymer precursor monomer in the flow state, and a magnetic field for applying a magnetic field to the monomer liquid in the flow state A flow reaction apparatus comprising an application means.

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