JP7462426B2 - Method for producing modified conductive composite, method for producing modified conductive composite dispersion, and method for producing conductive film - Google Patents

Description

The present invention relates to a method for producing a modified conductive composite, a method for producing a modified conductive composite dispersion, a method for producing a conductive film, and a conductive film.

As a coating material for forming a conductive layer, a conductive polymer-containing liquid containing a conductive complex in which poly(3,4-ethylenedioxythiophene) is doped with polystyrene sulfonic acid may be used.
Patent Document 1 discloses an organic solvent-based coating material for forming a conductive release layer, which contains a conductive complex that has been hydrophobized by reacting the sulfo group of polystyrene sulfonic acid with an epoxy compound, and a curable silicone.

JP 2018-009052 A

Patent Document 1 discloses a method for producing a paint in which an epoxy compound is added to a conductive complex that has been dispersed in advance in an aqueous dispersion medium, and a conductive complex that has been hydrophobized by reaction (modified conductive complex) is precipitated in the aqueous dispersion medium. In order to advance the hydrophobization reaction, it was necessary to add an equal or greater amount of water-soluble organic solvent to the aqueous dispersion medium, and to mix the hydrophobic epoxy compound and the water-soluble conductive complex uniformly in the reaction liquid. This resulted in problems with the amount of water-soluble organic solvent used increasing production costs and the amount of waste liquid to be treated after the reaction.

The present invention provides a method for producing a modified conductive composite with improved production efficiency, a method for producing a modified conductive composite dispersion, a method for producing a conductive film, and a conductive film.

[1] A method for producing a modified conductive composite, comprising the steps of adding an epoxy compound having a carbon number of 7 or less to a conductive polymer aqueous dispersion liquid containing a conductive complex containing a π-conjugated conductive polymer and a polyanion, and an aqueous dispersion medium, obtaining a heterogeneous liquid phase in which at least a part of the epoxy compound is insoluble in the aqueous dispersion medium, reacting the conductive complex with the epoxy compound in the heterogeneous liquid phase, and isolating the modified conductive composite precipitated in the aqueous dispersion medium.
[2] The method for producing a modified electrically conductive composite according to [1], wherein the content of water relative to the total mass of the aqueous dispersion medium is 60 mass % or more and 100 mass % or less.
[3] The method for producing a modified electrically conductive composite according to [1] or [2], wherein the method for isolating the modified electrically conductive composite is filtration or decantation.
[4] The method for producing the modified electrically conductive composite according to any one of [1] to [3], further comprising a step of washing the separated modified electrically conductive composite with water.
[5] The method for producing a modified conductive composite according to any one of [1] to [4], wherein the π-conjugated conductive polymer is poly(3,4-ethylenedioxythiophene).
[6] The method for producing a modified electrically conductive composite according to any one of [1] to [5], wherein the polyanion is polystyrene sulfonic acid.
[7] The method for producing a modified conductive composite according to any one of [1] to [6], wherein the epoxy compound contains butylene oxide or butyl glycidyl ether.
[8] A method for producing a modified conductive composite dispersion, comprising obtaining a modified conductive composite by the production method according to any one of [1] to [7], and mixing the modified conductive composite with an organic solvent.
[9] The method for producing the modified conductive composite dispersion according to [8], further comprising mixing a binder component.
[10] The method for producing a modified conductive composite dispersion according to [9], wherein the binder component contains a compound that forms an acrylic resin after curing.
[11] The method for producing a modified conductive composite dispersion according to [9], wherein the binder component contains a curable silicone.
[12] The method for producing a modified conductive composite dispersion liquid according to [11], wherein the curable silicone includes an addition-curable silicone.
[13] A method for producing a conductive film, comprising: coating at least one surface of a film substrate with the modified conductive complex dispersion obtained by the production method according to any one of [8] to [12], and drying the formed coating film.
[14] A conductive film comprising a conductive layer formed on at least one surface of a film substrate, the conductive layer being a cured layer of the modified conductive composite dispersion obtained by the production method according to any one of [8] to [12].

In the method for producing a modified conductive composite of the present invention, the reaction liquid is a heterogeneous liquid phase, the conductive composite is contained in the aqueous phase, and the epoxy compound is contained in the organic phase. In other words, no water-soluble organic solvent is required to dissolve the epoxy compound in the aqueous phase. Surprisingly, when the epoxy compound has a small number of carbon atoms and is relatively low in hydrophobicity, the conductive composite contained in the aqueous phase reacts with the epoxy compound. As a result, the modified conductive composite, which is the reaction product, is obtained as a precipitate in the aqueous phase.
The method for producing a modified conductive composite of the present invention does not require the addition of a water-soluble organic solvent, which was previously required. Another advantage is that the time required to separate the modified conductive composite precipitated in the aqueous phase of a heterogeneous liquid phase is shorter than the time required to separate the composite from a homogeneous reaction solution containing a water-soluble organic solvent (see the Examples and Comparative Examples described below). Thus, the method for producing a modified conductive composite of the present invention has extremely excellent production efficiency.
Furthermore, the method for producing a modified conductive composite dispersion according to the present invention and the method for producing a conductive film using the method for producing a modified conductive composite according to the present invention also naturally have excellent production efficiency.
Furthermore, the conductive film of the present invention has excellent conductivity.

<Method for producing modified conductive composite>
A first aspect of the present invention is a method for producing a modified conductive composite, comprising the steps of adding an epoxy compound having a carbon number of 7 or less to a conductive polymer aqueous dispersion liquid containing a conductive composite containing a π-conjugated conductive polymer and a polyanion, and an aqueous dispersion medium, obtaining a heterogeneous liquid phase in which at least a part of the epoxy compound is insoluble in the aqueous dispersion medium, reacting the conductive composite with the epoxy compound in the heterogeneous liquid phase, and isolating the modified conductive composite precipitated in the aqueous dispersion medium.

[Conductive polymer aqueous dispersion]
The conductive polymer aqueous dispersion used in this embodiment contains a conductive complex containing a π-conjugated conductive polymer and a polyanion, and an aqueous dispersion medium. This conductive polymer aqueous dispersion may contain an organic solvent to the extent that the conductive complex is in a dispersed state in the liquid and to the extent that the formation of the heterogeneous liquid phase is not hindered.

The polyanion is doped into the π-conjugated conductive polymer to form a conductive complex having electrical conductivity. In the polyanion, only some of the anionic groups are doped into the π-conjugated conductive polymer, and there are excess anionic groups that are not involved in the doping. Since the excess anionic groups are hydrophilic groups, the conductive complex has dispersibility in water.

The conductive complex contained in the conductive polymer aqueous dispersion used in this embodiment is in a dispersed state. The dispersed state and precipitated state can be easily distinguished by visual inspection. The dispersion liquid in the dispersed state has high transparency, and no solid floating matter is found in the dispersion liquid. On the other hand, the liquid in the precipitated state has low transparency, and solid floating matter is observed in the liquid. Usually, the conductive complex in the dispersed state does not easily precipitate, and precipitation is unlikely to occur even if the liquid is left to stand for, for example, 12 hours. On the other hand, the floating matter in the precipitated liquid is likely to settle, and precipitation is likely to occur when the liquid is left to stand for, for example, about 12 hours.

When the conductive polymer aqueous dispersion used in this embodiment is passed through a filter with a retention particle size of 7 μm, the conductive complex in a dispersed state passes through the filter together with the dispersion medium, while the conductive complex in a precipitated state can be captured by the filter.
Here, the retention particle size of the filter paper is a measure of the coarseness of the mesh, and is determined from the leaking particle size when barium sulfate or the like is naturally filtered as specified in JIS P 3801 [filter paper (for chemical analysis)].

(π-conjugated conductive polymer)
The π-conjugated conductive polymer may be an organic polymer whose main chain is composed of a π-conjugated system, and examples thereof include polypyrrole-based conductive polymers, polythiophene-based conductive polymers, polyacetylene-based conductive polymers, polyphenylene-based conductive polymers, polyphenylenevinylene-based conductive polymers, polyaniline-based conductive polymers, polyacene-based conductive polymers, polythiophenevinylene-based conductive polymers, and copolymers thereof. From the viewpoint of stability in air, polypyrrole-based conductive polymers, polythiophenes, and polyaniline-based conductive polymers are preferred, and from the viewpoint of transparency, polythiophene-based conductive polymers are more preferred.

Examples of polythiophene-based conductive polymers include polythiophene, poly(3-methylthiophene), poly(3-ethylthiophene), poly(3-propylthiophene), poly(3-butylthiophene), poly(3-hexylthiophene), poly(3-heptylthiophene), poly(3-octylthiophene), poly(3-decylthiophene), poly(3-dodecylthiophene), poly(3-octadecylthiophene), poly(3-bromothiophene), poly(3-chlorothiophene), and poly(3-iodothiophene). thiophene), poly(3-cyanothiophene), poly(3-phenylthiophene), poly(3,4-dimethylthiophene), poly(3,4-dibutylthiophene), poly(3-hydroxythiophene), poly(3-methoxythiophene), poly(3-ethoxythiophene), poly(3-butoxythiophene), poly(3-hexyloxythiophene), poly(3-heptyloxythiophene), poly(3-octyloxythiophene), poly(3-decyloxythiophene), poly(3-dodecyloxythiophene), oxythiophene), poly(3-octadecyloxythiophene), poly(3,4-dihydroxythiophene), poly(3,4-dimethoxythiophene), poly(3,4-diethoxythiophene), poly(3,4-dipropoxythiophene), poly(3,4-dibutoxythiophene), poly(3,4-dihexyloxythiophene), poly(3,4-diheptyloxythiophene), poly(3,4-dioctyloxythiophene), poly(3,4-didecyloxythiophene), poly(3,4-di dodecyloxythiophene), poly(3,4-ethylenedioxythiophene), poly(3,4-propylenedioxythiophene), poly(3,4-butylenedioxythiophene), poly(3-methyl-4-methoxythiophene), poly(3-methyl-4-ethoxythiophene), poly(3-carboxythiophene), poly(3-methyl-4-carboxythiophene), poly(3-methyl-4-carboxyethylthiophene), and poly(3-methyl-4-carboxybutylthiophene).
Examples of polypyrrole-based conductive polymers include polypyrrole, poly(N-methylpyrrole), poly(3-methylpyrrole), poly(3-ethylpyrrole), poly(3-n-propylpyrrole), poly(3-butylpyrrole), poly(3-octylpyrrole), poly(3-decylpyrrole), poly(3-dodecylpyrrole), poly(3,4-dimethylpyrrole), poly(3,4-dibutylpyrrole), poly(3-carboxypyrrole), poly(3-methyl-4-carboxypyrrole), poly(3-methyl-4-carboxyethylpyrrole), poly(3-methyl-4-carboxybutylpyrrole), poly(3-hydroxypyrrole), poly(3-methoxypyrrole), poly(3-ethoxypyrrole), poly(3-butoxypyrrole), poly(3-hexyloxypyrrole), and poly(3-methyl-4-hexyloxypyrrole).
Examples of polyaniline-based conductive polymers include polyaniline, poly(2-methylaniline), poly(3-isobutylaniline), poly(2-anilinesulfonic acid), and poly(3-anilinesulfonic acid).
Among these π-conjugated conductive polymers, poly(3,4-ethylenedioxythiophene) is particularly preferable from the viewpoints of conductivity, transparency, and heat resistance.
The conductive composite may contain one type of π-conjugated conductive polymer, or two or more types of polymers.

(Polyanion)
A polyanion is a polymer having two or more monomer units each having an anionic group in the molecule. The anionic group of the polyanion functions as a dopant for a π-conjugated conductive polymer, thereby improving the conductivity of the π-conjugated conductive polymer.
The anion group of the polyanion is preferably a sulfo group or a carboxy group.
Specific examples of such polyanions include polymers having a sulfo group, such as polystyrene sulfonic acid, polyvinyl sulfonic acid, polyallyl sulfonic acid, polyacrylic acid esters having a sulfo group, polymethacrylic acid esters having a sulfo group (e.g., poly(4-sulfobutyl methacrylate, polysulfoethyl methacrylate, polymethacryloyloxybenzenesulfonic acid), poly(2-acrylamido-2-methylpropanesulfonic acid), and polyisoprene sulfonic acid; and polymers having a carboxy group, such as polyvinyl carboxylic acid, polystyrene carboxylic acid, polyallyl carboxylic acid, polyacrylic acid, polymethacrylic acid, poly(2-acrylamido-2-methylpropanecarboxylic acid), and polyisoprene carboxylic acid. The polyanion may be a homopolymer in which a single monomer is polymerized, or a copolymer in which two or more monomers are polymerized.
Among these polyanions, polymers having a sulfo group are preferred, and polystyrene sulfonic acid is more preferred, since they can provide higher electrical conductivity.
The polyanions may be used alone or in combination of two or more kinds.
The mass average molecular weight of the polyanion is preferably from 20,000 to 1,000,000, and more preferably from 100,000 to 500,000. The mass average molecular weight is the average molecular weight based on mass measured by gel permeation chromatography and calculated in terms of polystyrene.

The content of the polyanion in the conductive complex is preferably in the range of 1 to 1000 parts by mass, more preferably 10 to 700 parts by mass, and even more preferably 100 to 500 parts by mass, per 100 parts by mass of the π-conjugated conductive polymer. If the content of the polyanion is equal to or greater than the lower limit, the doping effect on the π-conjugated conductive polymer tends to be stronger, and the conductivity becomes higher. On the other hand, if the content of the polyanion is equal to or less than the upper limit, the π-conjugated conductive polymer can be sufficiently contained, so that sufficient conductivity can be ensured.

<Method of producing conductive polymer aqueous dispersion>
A conductive complex containing a π-conjugated conductive polymer and a polyanion can be obtained, for example, by chemically oxidizing and polymerizing a monomer that forms a π-conjugated conductive polymer in an aqueous solution of the polyanion.

The chemical oxidative polymerization can be carried out using a known catalyst and oxidizing agent. Examples of catalysts include transition metal compounds such as ferric chloride, ferric sulfate, ferric nitrate, and cupric chloride. Examples of oxidizing agents include persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate. The oxidizing agent can return the reduced catalyst to its original oxidized state.

The content of the conductive complex contained in the conductive polymer aqueous dispersion of this embodiment is, for example, preferably 0.1 mass % or more and 20 mass % or less, more preferably 0.5 mass % or more and 10 mass % or less, and more preferably 1.0 mass % or more and 5.0 mass % or less, relative to the total mass of the conductive polymer aqueous dispersion.
When the content is equal to or greater than the lower limit of the above range, precipitation of the modified conductive composite after the addition of the epoxy compound becomes easy. When the content is equal to or less than the upper limit of the above range, the dispersibility of the conductive composite in the conductive polymer aqueous dispersion is increased, so that unintended aggregation during storage of the conductive polymer aqueous dispersion can be prevented and the quality of the modified conductive composite precipitated after the addition of the epoxy compound can be made uniform.

The conductive polymer aqueous dispersion used in this embodiment may contain an organic solvent to the extent that the conductive complex is in a dispersed state and to the extent that the formation of a heterogeneous liquid phase is not hindered, but from the viewpoint of improving the dispersibility of the conductive complex, the smaller the content of the organic solvent, the more preferable. The content of the organic solvent relative to the total mass of the conductive polymer aqueous dispersion is, for example, preferably 10 mass% or less, more preferably 5 mass% or less, even more preferably 1 mass% or less, and particularly preferably substantially not contained.
The organic solvent that may be contained in the conductive polymer aqueous dispersion used in this embodiment is preferably one that is highly miscible with water, and examples thereof include alcohol-based solvents such as methanol, ethanol, and isopropanol.

[Heterogeneous liquid phase]
The method of adding an epoxy compound to a conductive polymer aqueous dispersion to obtain a heterogeneous liquid phase may be any method that can mix the conductive polymer aqueous dispersion and the epoxy compound. When the conductive polymer aqueous dispersion and the epoxy compound are mixed, a heterogeneous liquid phase separated into an aqueous phase and an organic phase is formed. In addition, the heterogeneous liquid phase may be separated again into an aqueous phase and an organic phase by stirring and then leaving it to stand. If the separation of the aqueous phase and the organic phase is unclear, the precipitation of the modified conductive complex formed by the reaction may be insufficient, or the time required for separating the modified conductive complex may be long.

In order to clearly separate the aqueous phase and the organic phase in the heterogeneous liquid phase, the water content relative to the total mass of the aqueous dispersion medium constituting the conductive polymer aqueous dispersion is preferably 60% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and even more preferably 98% by mass or more and 100% by mass or less.

In order to clearly separate the aqueous phase and the organic phase in the heterogeneous liquid phase, the temperature of the heterogeneous liquid phase is preferably 10°C or higher and 100°C or lower, more preferably 15°C or higher and 80°C or lower, and even more preferably 20°C or higher and 60°C or lower.

If the carbon number of the epoxy compound contained in the organic phase forming the heterogeneous liquid phase is 7 or less, the target reaction proceeds at the interface between the aqueous phase and the organic phase. Although the details of this mechanism are not yet clear, it is speculated that the epoxy compound with a small carbon number gradually diffuses from the organic phase to the aqueous phase and reacts with the conductive composite. In order for the above reaction to proceed in this way, it is preferable that the epoxy compound has low hydrophobicity and that the epoxy compound has a small number of carbon atoms, so the number of carbon atoms of the epoxy compound is 7 or less, preferably 6 or less, more preferably 5 or less, and even more preferably 4 or less. Specific examples of suitable epoxy compounds will be described later.

The temperature during the reaction in the heterogeneous liquid phase is preferably a temperature at which the aqueous phase and the organic phase are clearly separated, as described above.
The completion of the reaction in the heterogeneous liquid phase can be judged based on the amount of the modified conductive complex precipitated in the aqueous phase, and the reaction can be completed within, for example, 1 hour to 24 hours.

[Deposition of modified conductive composite]
There is no particular limitation on the method for precipitating the modified conductive complex in the aqueous phase of the heterogeneous liquid phase. The heterogeneous liquid phase may be left to stand to allow the reaction to proceed and to allow natural precipitation, but it is preferable to stir the heterogeneous liquid phase to increase the interface and promote the reaction. The modified conductive complex produced by the reaction is obtained in a state of being precipitated in the aqueous phase.

From the viewpoint of easily precipitating the modified conductive complex in the aqueous phase, the mass ratio of the aqueous phase to the organic phase constituting the heterogeneous liquid phase is preferably such that the mass of the aqueous phase is greater than the mass of the organic phase, and the mass of the aqueous phase/the mass of the organic phase is preferably 1.5 or more and 100 or less, more preferably 2 or more and 50 or less, even more preferably 3 or more and 25 or less, and particularly preferably 4 or more and 10 or less.
When the concentration is equal to or higher than the lower limit of the above range, the modified conductive complex easily precipitates in the aqueous phase, and when the concentration is equal to or lower than the upper limit of the above range, the interface area between the aqueous phase and the organic phase becomes appropriate, improving the reaction efficiency.

The content of the epoxy compound contained in the organic phase of the heterogeneous liquid phase is preferably 80% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and even more preferably 95% by mass or more and 100% by mass or less, based on the total mass of the organic phase. The organic phase may contain an organic solvent as a diluent for the epoxy compound, but from the viewpoint of increasing the reaction efficiency and the yield of the precipitate, it is preferable that the organic phase does not contain an organic solvent.
The epoxy compound contained in the organic phase of the heterogeneous liquid phase may be one type or two or more types.

The mass ratio of the conductive complex to the epoxy compound in the heterogeneous liquid phase is preferably 1 part by mass or more and 10,000 parts by mass or less of the epoxy compound per 100 parts by mass of the conductive complex, more preferably 100 parts by mass or more and 5,000 parts by mass or less, and even more preferably 200 parts by mass or more and 3,000 parts by mass or less. When the ratio of the epoxy compound added is within the above range, a modified conductive complex is easily formed, and the amount of the epoxy compound remaining unreacted can be reduced.

[Addition of epoxy compounds]
The modified conductive composite obtained by reacting an epoxy compound with some of the anion groups of the polyanion constituting the conductive composite is rendered hydrophobic compared to the conductive composite, and has high dispersibility in organic solvents.
The structure of the substituent formed by adding an epoxy compound to the excess anion group not involved in the doping of the polyanion is considered to be a substituent (A) represented by the following chemical formula (A1) or the following chemical formula (A2) formed by a ring-opening reaction of the epoxy group.

［式（Ａ１）中、Ｒ^１１、Ｒ^１２、Ｒ^１３、及びＲ^１４はそれぞれ独立に、水素原子、又は任意の置換基である。］

[In formula (A1), R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ each independently represent a hydrogen atom or any substituent.]

［式（Ａ２）中、ｍは２以上の整数であり、複数のＲ^１５、複数のＲ^１６、複数のＲ^１７、及び複数のＲ^１８はそれぞれ独立に、水素原子、又は任意の置換基であり、複数のＲ^１５は同一でも異なっていてもよく、複数のＲ^１６は同一でも異なっていてもよく、複数のＲ^１７は同一でも異なっていてもよく、複数のＲ^１８は同一でも異なっていてもよい。］

[In formula (A2), m is an integer of 2 or more, a plurality of R ^{15 s} , a plurality of R ^{16 s} , a plurality of R ^{17 s} , and a plurality of R ^{18 s} are each independently a hydrogen atom or any substituent, a plurality of R ^{15 s} may be the same or different, a plurality of R ^{16 s} may be the same or different, a plurality of R ^{17 s} may be the same or different, and a plurality of R ^{18 s} may be the same or different.]

In formula (A1) and formula (A2), the bond at the left end represents that the substituent (A) is substituted with a proton of an anionic group. Examples of the anionic group having a substituted proton include an anionic group having an active proton bonded to an oxygen atom, such as "-SO ₃ H".

In formula (A1), the optional substituents of R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ include an aliphatic hydrocarbon group having 1 to 4 carbon atoms which may have a substituent. R ¹¹ and R ¹³ may be bonded to form a ring which may have a substituent. For example, R ¹¹ and R ¹³ may be the above-mentioned hydrocarbon group, and a divalent hydrocarbon group obtained by removing any one hydrogen atom from the monovalent hydrocarbon group of R ¹¹ and a divalent hydrocarbon group obtained by removing any one hydrogen atom from the monovalent hydrocarbon group of R ¹³ may be bonded to each other via the carbon atoms from which the hydrogen atoms have been removed to form a ring.

In this specification, the term "optionally substituted" includes both the case where a hydrogen atom (-H) is replaced with a monovalent group and the case where a methylene group (-CH ₂ -) is replaced with a divalent group.
Examples of the monovalent group as a substituent include a halogen atom (such as a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), a trialkoxysilyl group (such as a trimethoxysilyl group), and the like.
Examples of the divalent group as a substituent include an oxygen atom (-O-), -C(=O)-, -C(=O)-O-, etc., except for the case where two oxygen atoms are adjacent to each other.

In formula (A2), the optional substituents of R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ include an aliphatic hydrocarbon group having 1 to 4 carbon atoms which may have a substituent. R ¹⁵ and R ¹⁷ may be bonded to form a ring which may have a substituent. Examples of the ring are the same as those mentioned above.

In formula (A2), m is an integer of 2 or more, preferably 2 to 100, more preferably 2 to 50, and even more preferably 2 to 25. When m is equal to or greater than the lower limit, the hydrophobicity of the modified conductive composite is sufficiently high. When m is equal to or less than the upper limit, it is possible to prevent the hydrophobicity from becoming too high or the conductivity from decreasing.

The epoxy compound is a compound having one or more epoxy groups in one molecule.
The epoxy compounds may be used alone or in combination of two or more.

Examples of monofunctional epoxy compounds having one epoxy group per molecule and 7 or less carbon atoms include ethylene oxide, propylene oxide, 2,3-butylene oxide, isobutylene oxide, 1,2-butylene oxide, 1,2-epoxyhexane, 1,2-epoxyheptane, 1,2-epoxypentane, 1,3-butadiene monoxide, glycidyl methyl ether, ethyl glycidyl ether, glycidyl isopropyl ether, tert-butyl glycidyl ether, 2-(chloromethyl)-1,2-epoxypropane, Pan, glycidol, epichlorohydrin, epibromohydrin, butyl glycidyl ether, 1,2-epoxyhexane, 2-(chloromethyl)-1,2-epoxybutane, allyl glycidyl ether, tetracyanoethylene oxide, glycidyl butyrate, glycidyl methacrylate, 1-methyl-1,2-epoxycyclohexane, 1,2-epoxycyclopentane, 1,2-epoxycyclohexane, 3,4-epoxytetrahydrofuran, epoxysuccinic acid, 2,3-epoxynorbornene, etc.

An example of a polyfunctional epoxy compound with two or more epoxy groups in one molecule and seven or less carbon atoms is 1,2:3,4-diepoxybutane.

Among the epoxy compounds listed above, butylene oxide or butyl glycidyl ether is preferred because it is easy to form a heterogeneous liquid phase and to obtain the desired product.

[Isolation of modified conductive composite]
The method for separating (recovering) the aqueous phase of the heterogeneous liquid phase, i.e., the modified conductive composite precipitated in the aqueous dispersion medium, is not particularly limited, and examples thereof include filtration, decantation, centrifugation, reduced pressure drying, freeze drying, spray drying, etc.
Among these, filtration or decantation is preferred because it is easy to separate the modified conductive complex from components other than the modified conductive complex contained in the aqueous phase of the heterogeneous liquid phase. Here, filtration is an operation of capturing the modified conductive complex in a filter through which the aqueous phase of the heterogeneous liquid phase has been passed. Decantation is an operation of precipitating the precipitated modified conductive complex and removing the supernatant.
Filtration is very suitable for separating out the modified conductive composite precipitated in the aqueous phase of a heterogeneous liquid phase. When separating out the modified conductive composite precipitated by a conventional method by filtration, it was necessary to deal with clogging of the filter. However, the modified conductive composite according to the present invention can be separated out by filtration in an extremely short time without causing clogging of the filter.
When the modified conductive composite precipitated in the aqueous phase of the heterogeneous liquid phase is separated by decantation, the modified conductive composite is obtained in a relatively soft powder state, which can be easily dispersed in a dispersion medium later. However, when separating by decantation, it is necessary to wait until the modified conductive composite precipitates in the aqueous phase. From the viewpoint of increasing the production speed of the modified conductive composite, it is more preferable to separate by filtration.

The separated modified conductive complex is preferably washed with water or an organic solvent that hardly dissolves the modified conductive complex. Specifically, for example, water may be poured onto the filter capturing the modified conductive complex, or water may be added to the modified conductive complex remaining at the bottom of the container after decantation, and the mixture may be stirred and then separated again by decantation or the like.
The water and the like adhering to the separated modified electrically conductive composite can be removed by drying to obtain a dried modified electrically conductive composite.

<Action and effect>
According to the method for producing a modified conductive composite of the present invention, 90 to 100 parts by mass of the conductive composite can be recovered as a precipitate based on 100 parts by mass of the conductive composite contained in the conductive polymer dispersion. In other words, the method for producing a modified conductive composite of this embodiment can show a high yield of 90 to 100% by mass.
In the method for producing a modified conductive composite of the present invention, if the carbon number of the epoxy compound contained in the organic phase of the heterogeneous liquid phase is 7 or less, the reaction with the conductive composite in the aqueous phase proceeds, and the desired modified conductive composite can be precipitated in the aqueous phase (see the Examples described later). Although the details of this mechanism are not yet clear, it is believed that if the carbon number of the epoxy compound is 7 or less, a part of the epoxy compound diffuses into the aqueous phase and reacts with the conductive composite. The epoxy compound does not entirely diffuse into the aqueous phase and dissolve, and it is observed to maintain an equilibrium state between diffusion and reabsorption.
On the other hand, if the carbon number of the epoxy compound is 8 or more, the reaction with the conductive composite does not proceed easily (see the Comparative Example described later). This is thought to be because an epoxy compound with a large carbon number and high hydrophobicity does not easily diffuse into the aqueous phase and does not easily react with the conductive composite even at the interface.
According to the method for producing a modified conductive composite of the present invention, it is not necessary to use a water-soluble organic solvent for dissolving an epoxy compound in an aqueous phase. Moreover, the modified conductive composite precipitated in the aqueous phase can be filtered in an extremely short time without clogging the filter paper. Conventionally, when a modified conductive composite precipitated in a homogeneous reaction solution containing an organic solvent is filtered, a considerable amount of time was required to filter the reaction solution. In this embodiment, since the modified conductive composite is precipitated in the aqueous phase, which is a poor solvent, it is considered that the morphology of the modified conductive composite is in a state suitable for filtration.
Furthermore, after the reaction in the heterogeneous liquid phase, the epoxy compound remaining unreacted in the organic phase can be recovered as it is and used as a material for forming the next heterogeneous liquid phase.
Thus, the present invention is more efficient in production than conventional manufacturing methods with less waste of materials. Furthermore, the conductive layer containing the modified conductive composite of the present invention has excellent conductivity.

<Method for producing modified conductive composite dispersion>
A second aspect of the present invention is a method for producing a modified conductive composite dispersion, comprising obtaining a modified conductive composite by the production method of the first aspect, and mixing the modified conductive composite with an organic solvent.
The modified conductive composite obtained in the first embodiment has high dispersibility in organic solvents and can be easily dispersed in organic solvents.
The modified conductive complex used in this embodiment may be separated by the production method of the first embodiment and then dried and stored, or may be used immediately without storage.

(Organic solvent)
Examples of the organic solvent used in the production method of this embodiment include hydrocarbon solvents, ketone solvents, alcohol solvents, ester solvents, nitrogen atom-containing compound solvents, etc. The organic solvents may be used alone or in combination of two or more.
Examples of the hydrocarbon solvent include aliphatic hydrocarbon solvents and aromatic hydrocarbon solvents. Examples of the aliphatic hydrocarbon solvent include pentane, hexane, heptane, octane, decane, cyclohexane, methylcyclohexane, etc. Examples of the aromatic hydrocarbon solvent include benzene, toluene, xylene, ethylbenzene, propylbenzene, isopropylbenzene, etc.
Examples of the ketone solvent include diethyl ketone, methyl propyl ketone, methyl butyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, methyl amyl ketone, diisopropyl ketone, methyl ethyl ketone, acetone, and diacetone alcohol.
Examples of the alcohol solvent include methanol, ethanol, isopropanol, n-butanol, t-butanol, and allyl alcohol.
Examples of the ester solvent include ethyl acetate, propyl acetate, and butyl acetate.
Examples of the nitrogen atom-containing compound solvent include N-methylpyrrolidone, dimethylacetamide, and dimethylformamide.

Among the above organic solvents, ketone-based solvents or alcohol-based solvents are preferred because they increase the wettability of the modified conductive composite dispersion liquid with respect to the plastic film substrate and can easily solubilize binder components with relatively high polarity. Among the ketone-based solvents, methyl ethyl ketone is preferred because it has good dispersibility of the modified conductive composite. Among the alcohol-based solvents, isopropanol is preferred because it has good dispersibility of the modified conductive composite.

The content of the organic solvent is preferably 50% by mass or more and 99.5% by mass or less, and more preferably 70% by mass or more and 99% by mass or less, based on the total mass of the modified conductive composite dispersion. When the content of the organic solvent is within the above range, the dispersibility of the modified conductive composite can be improved.

In this embodiment, the method for mixing the modified conductive composite with the organic solvent is not particularly limited, and a method in which the components are mixed and dispersed using a high-pressure homogenizer is preferred.

The content of the modified conductive complex relative to the total mass of the modified conductive complex dispersion of this embodiment is, for example, preferably 0.01 mass % or more and 10 mass % or less, more preferably 0.1 mass % or more and 5 mass % or less, and even more preferably 0.5 mass % or more and 1.0 mass % or less.
When the content is within the above range, the modified conductive composite can be dispersed more stably.

(Binder Component)
The modified conductive complex dispersion of this embodiment may contain a binder component. The binder component is a resin other than the π-conjugated conductive polymer and the polyanion or a precursor thereof, and is a thermoplastic resin, or a curable monomer or oligomer that is cured when forming a conductive layer (conductive film). The thermoplastic resin becomes the binder resin as it is, and the curable monomer or oligomer becomes the resin formed by curing becomes the binder resin.
The binder component may be used alone or in combination of two or more kinds.

The curable monomer or oligomer may be a thermosetting monomer or oligomer, or a photocurable monomer or oligomer. Here, the oligomer refers to a polymer having a mass average molecular weight of less than 10,000.
Examples of the curable monomer include an acrylic monomer (acrylic compound), an epoxy monomer, an organosiloxane, etc. Examples of the curable oligomer include an acrylic oligomer (acrylic compound), an epoxy oligomer, a silicone oligomer (curable silicone), etc.
When an acrylic monomer or an acrylic oligomer is used as the binder component, it can be easily cured by heating or light irradiation. When an organosiloxane or a silicone oligomer is used as the binder component, it is possible to impart releasability (non-adhesiveness) to the conductive layer.

When a curable monomer or oligomer is included, it is preferable to further include a curing catalyst. For example, when a thermosetting monomer or oligomer is included, it is preferable to include a thermal polymerization initiator that generates radicals by heating, and when a photocurable monomer or oligomer is included, it is preferable to include a photopolymerization initiator that generates radicals by light irradiation. Furthermore, when an organosiloxane or silicone oligomer is included, it is preferable to include a platinum catalyst for curing.

Specific examples of binder resins derived from binder components include acrylic resins, polyester resins, polyurethane resins, polyimide resins, polyether resins, melamine resins, polyacrylamide resins, and silicones.
As the binder resin contained in the modified conductive composite dispersion liquid of this embodiment, a compound that forms an acrylic resin after curing (acrylic compound), a polyurethane resin, a polyester resin, or an addition-curing silicone is preferred, since these have good dispersibility in organic solvents.

The content of the binder component in the modified conductive complex dispersion of this embodiment is preferably 500 parts by mass or more and 50,000 parts by mass or less, and more preferably 1,000 parts by mass or more and 20,000 parts by mass or less, relative to 100 parts by mass of the modified conductive complex. If the content of the binder component is equal to or more than the lower limit, the film formability and film strength when the modified conductive complex dispersion of this embodiment is applied to a film substrate can be improved. If the content of the binder component is equal to or less than the upper limit, the decrease in conductivity due to the decrease in the content of the modified conductive complex can be suppressed.

<Other additives>
The modified conductive composite dispersion of this embodiment may contain other additives.
The additives are not particularly limited as long as the effects of the present invention can be obtained, and examples thereof include surfactants, inorganic conductive agents, antifoaming agents, coupling agents, antioxidants, ultraviolet absorbers, etc. However, the additives are other than the π-conjugated conductive polymers, polyanions, organic solvents, and binder components.
The surfactant may be a nonionic, anionic or cationic surfactant, with the nonionic surfactant being preferred from the standpoint of storage stability. A polymer surfactant such as polyvinylpyrrolidone may also be added.
Examples of the inorganic conductive agent include metal ions, conductive carbon, etc. Metal ions can be generated by dissolving a metal salt in water.
The antifoaming agent includes silicone resin, polydimethylsiloxane, silicone oil, and the like.
The coupling agent may be a silane coupling agent having a vinyl group or an amino group.
Examples of the ultraviolet absorber include benzotriazole-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, salicylate-based ultraviolet absorbers, cyanoacrylate-based ultraviolet absorbers, oxanilide-based ultraviolet absorbers, hindered amine-based ultraviolet absorbers, and benzoate-based ultraviolet absorbers.
When the dispersion liquid of the modified conductive composite of this embodiment contains the above-mentioned additive, the content ratio thereof is appropriately determined depending on the type of additive, but can be, for example, in the range of 0.001 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the solid content of the modified conductive composite.

<Action and effect>
The method for producing a modified conductive composite dispersion of the present invention has excellent production efficiency because a modified conductive composite is obtained by the production method of the first embodiment.

<Conductive film manufacturing method>
The conductive film manufacturing method of the third aspect of the present invention is a conductive film manufacturing method comprising applying the modified conductive composite dispersion obtained by the manufacturing method of the second aspect to at least one surface of a film substrate and drying the formed coating film.

The film substrate used in this embodiment is, for example, a plastic film.
Examples of the resin for film substrate constituting the plastic film include ethylene-methyl methacrylate copolymer resin, ethylene-vinyl acetate copolymer resin, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinyl alcohol, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyacrylate, polycarbonate, polyvinylidene fluoride, polyarylate, styrene-based elastomer, polyester-based elastomer, polyethersulfone, polyetherimide, polyetheretherketone, polyphenylene sulfide, polyimide, cellulose triacetate, cellulose acetate propionate, etc. Among these resins for film substrate, polyethylene terephthalate is preferred because it is inexpensive and has excellent mechanical strength.
The resin for the film substrate may be either amorphous or crystalline.
The film substrate may be either unstretched or stretched.
Furthermore, the film substrate may be subjected to a surface treatment such as a corona discharge treatment, a plasma treatment, or a flame treatment in order to further improve the adhesion of the conductive layer to be formed.

The average thickness of the film substrate is preferably 10 μm or more and 500 μm or less, and more preferably 20 μm or more and 200 μm or less. If the average thickness of the film substrate is equal to or more than the lower limit, the film substrate is less likely to break, and if the average thickness is equal to or less than the upper limit, the film substrate can have sufficient flexibility.
In this specification, the thickness of the film substrate is a value obtained by measuring the thickness of 10 randomly selected cross sections and averaging the measured values.

(Coating process)
Examples of a method for applying the modified conductive complex dispersion to the film substrate include a coating method using a coater such as a gravure coater, a roll coater, a curtain flow coater, a spin coater, a bar coater, a reverse coater, a kiss coater, a fountain coater, a rod coater, an air doctor coater, a knife coater, a blade coater, a cast coater, or a screen coater; a spraying method using a sprayer such as an air spray, an airless spray, or a rotor dampening; and an immersion method such as dipping.
The amount of the dispersion applied to the film substrate is not particularly limited, but from the viewpoint of obtaining good electrical conductivity, the amount is preferably in the range of 0.1 g/m ² or more and 10.0 g/m ² or less in terms of solid content.

The coating film may be applied to the entire surface of the film substrate, or may be formed only on a portion of the surface, and any pattern may be formed on the film substrate. Examples of the pattern include electrodes, wiring, and electric circuits. Applying the coating by printing makes it easier to form a pattern.

(Drying process)
Examples of methods for drying the coating film formed on the film substrate include heat drying and vacuum drying. For heat drying, for example, a normal method such as hot air heating or infrared heating can be adopted. When heat drying is applied, the heating temperature is appropriately set according to the dispersion medium used, and can be set, for example, to 50°C or higher and 150°C or lower. Here, the heating temperature is the set temperature of the drying device. The drying time when drying at the above temperature can be, for example, 30 seconds or higher and 5 minutes or lower.

<Conductive film>
A fourth aspect of the present invention is a conductive film having a conductive layer formed on at least one surface of a film substrate, the conductive layer being a cured layer of the modified conductive composite dispersion obtained by the production method of the second aspect. The conductive film of this aspect can be produced by the production method of the third aspect.

The conductive film obtained by this embodiment comprises a film substrate and a conductive layer formed on at least one surface of the film substrate. The conductive layer contains the modified conductive complex of the first embodiment.

The average thickness of the conductive layer of the conductive film of this embodiment is, for example, preferably 10 nm to 30 μm, more preferably 30 nm to 10 μm. If the average thickness of the conductive layer is equal to or greater than the lower limit, the conductive layer can exhibit sufficiently high conductivity, and if the average thickness is equal to or less than the upper limit, the adhesiveness of the conductive layer to the film substrate is improved.
The thickness of the conductive layer is a value measured by using an optical microscope or an electron microscope on a cross section of the conductive layer at an arbitrarily selected location.
The conductive layer may be formed in a pattern on the surface of the film substrate, or may be formed over the entire surface of the film substrate.

The surface resistance of the conductive layer of the conductive film of this embodiment is, for example, preferably 1×10 ² Ω/□ to 1×10 ⁸ Ω/□, more preferably 1×10 ³ Ω/□ to 1×10 ⁷ Ω/□, and even more preferably 1×10 ⁴ Ω/□ to 1×10 ⁶ Ω/□.

(Production Example 1) Synthesis of polystyrene sulfonic acid 206 g of sodium styrene sulfonate was dissolved in 1000 ml of ion-exchanged water, and while stirring at 80° C., 1.14 g of an oxidizing agent solution of ammonium persulfate previously dissolved in 10 ml of water was added dropwise for 20 minutes, and the solution was stirred for 12 hours.
1000ml of sulfuric acid diluted to 10% by mass was added to the obtained sodium styrenesulfonate-containing solution, and about 1000ml of the polystyrenesulfonic acid-containing solution was removed by ultrafiltration. 2000ml of ion-exchanged water was added to the remaining liquid, and about 2000ml of the solution was removed by ultrafiltration. The above ultrafiltration operation was repeated three times. Furthermore, about 2000ml of ion-exchanged water was added to the obtained filtrate, and about 2000ml of the solution was removed by ultrafiltration. This ultrafiltration operation was repeated three times.
Water in the resulting solution was removed under reduced pressure to obtain colorless solid polystyrene sulfonic acid.

(Production Example 2) Synthesis of conductive polymer aqueous dispersion 14.2 g of 3,4-ethylenedioxythiophene and a solution in which 36.7 g of polystyrene sulfonic acid was dissolved in 2000 ml of ion-exchanged water were mixed at 20°C.
The resulting mixed solution was kept at 20° C. and, while stirring, 29.64 g of ammonium persulfate and 8.0 g of an oxidation catalyst solution of ferric sulfate dissolved in 200 ml of ion-exchanged water were slowly added, and the mixture was reacted with stirring for 3 hours.
To the reaction solution obtained, 2000 ml of ion-exchanged water was added, and about 2000 ml of the solvent was removed by ultrafiltration. This operation was repeated three times.
Then, 200 ml of sulfuric acid diluted to 10% by mass and 2000 ml of ion-exchanged water were added to the obtained solution, and about 2000 ml of the solvent was removed by ultrafiltration. 2000 ml of ion-exchanged water was added to the remaining liquid, and about 2000 ml of the solution was removed by ultrafiltration. This operation was repeated three times.
Further, 2000 ml of ion-exchanged water was added to the obtained solution, and about 2000 ml of the solvent was removed by ultrafiltration. This operation was repeated five times to obtain a 1.2 mass% aqueous dispersion of polystyrenesulfonic acid-doped poly(3,4-ethylenedioxythiophene) (PEDOT-PSS). The content of PSS relative to the PEDOT-PSS solid content was 75 mass%.
The PEDOT-PSS aqueous dispersion thus obtained does not substantially contain iron ions or ammonium persulfate.

Example 1
25 g of butyl glycidyl ether was added to 100 g of the PEDOT-PSS aqueous dispersion of Production Example 2. At this time, it was confirmed that butyl glycidyl ether did not dissolve in the PEDOT-PSS aqueous dispersion, and a heterogeneous liquid phase was formed. When the heterogeneous liquid phase was heated and stirred at 60°C for 4 hours and then allowed to stand at room temperature (25°C), a modified conductive composite was precipitated in the aqueous phase of the heterogeneous liquid phase. The precipitate in the aqueous phase was filtered and washed with 100 g of water to obtain 1.4 g of a modified conductive composite.
The time required for filtering the precipitate is shown in Table 1.
198.6 g of isopropanol was added to 1.4 g of the modified conductive composite obtained, and the mixture was dispersed in a high-pressure homogenizer to obtain a modified conductive composite dispersion. The modified conductive composite dispersion was then applied onto a PET film (Torel Mirror T60) using a #8 bar coater, and dried at 150° C. for 1 minute to obtain a conductive film.

Example 2
25 g of butylene oxide was added to 100 g of the PEDOT-PSS aqueous dispersion of Production Example 2. At this time, it was confirmed that butylene oxide did not dissolve in the PEDOT-PSS aqueous dispersion, and a heterogeneous liquid phase was formed. The heterogeneous liquid phase was heated and stirred at 60°C for 4 hours, and then allowed to stand at room temperature (25°C), whereupon a modified conductive complex was precipitated in the aqueous phase of the heterogeneous liquid phase. The precipitate in the aqueous phase was filtered and washed with 100 g of water to obtain 1.3 g of a modified conductive complex.
The time required for filtering the precipitate is shown in Table 1.
198.7 g of isopropanol was added to 1.3 g of the modified conductive composite obtained, and the mixture was dispersed in a high-pressure homogenizer to obtain a modified conductive composite dispersion. The modified conductive composite dispersion was then applied onto a PET film using a #8 bar coater, and dried at 150° C. for 1 minute to obtain a conductive film.

Example 3
The conductive complex was reacted with butyl glycidyl ether to obtain 1.4 g of a modified conductive complex in the same manner as in Example 1. The time required for filtering this modified conductive complex is shown in Table 1.
198.6 g of methyl ethyl ketone was added to 1.4 g of the modified conductive composite obtained, and the mixture was dispersed in a high-pressure homogenizer to obtain a modified conductive composite dispersion. The modified conductive composite dispersion was then applied onto a PET film using a #8 bar coater, and dried at 150° C. for 1 minute to obtain a conductive film.

(Comparative Example 1)
25 g of 1,2-epoxy-4-vinylcyclohexane was added to 100 g of the PEDOT-PSS aqueous dispersion of Preparation Example 2. At this time, it was confirmed that 1,2-epoxy-4-vinylcyclohexane did not dissolve in the PEDOT-PSS aqueous dispersion, and a heterogeneous liquid phase was formed. When the heterogeneous liquid phase was heated and stirred at 60°C for 4 hours and then allowed to stand at room temperature, no precipitate was found in the aqueous phase of the heterogeneous liquid phase. Next, when the aqueous phase was passed through filter paper, all the components passed through the filter paper, and the subsequent experiment was discontinued.

(Comparative Example 2)
25 g of Epolight M-1230 (Kyoeisha Chemical Co., Ltd., C12, 13 mixed higher alcohol glycidyl ether) was added to 100 g of the PEDOT-PSS aqueous dispersion of Production Example 2. At this time, it was confirmed that Epolight M-1230 did not dissolve in the PEDOT-PSS aqueous dispersion, and a heterogeneous liquid phase was formed. When the heterogeneous liquid phase was heated and stirred at 60°C for 4 hours and then allowed to stand at room temperature, no precipitate was found in the aqueous phase of the heterogeneous liquid phase. Next, when the aqueous phase was passed through filter paper, all the components passed through the filter paper, so the subsequent experiment was discontinued.

(Comparative Example 3)
300 g of methanol and 25 g of butyl glycidyl ether were added to 100 g of the PEDOT-PSS aqueous dispersion of Production Example 2. At this time, it was confirmed that the butyl glycidyl ether was dissolved in the PEDOT-PSS aqueous dispersion to form a homogeneous mixture. When this mixture was heated and stirred at 60°C for 4 hours and then allowed to stand at room temperature, a modified conductive composite was precipitated in the mixture. The precipitate in the mixture was filtered and washed with 100 g of water to obtain 1.4 g of a modified conductive composite.
The time required for filtering the precipitate is shown in Table 1.
198.6 g of isopropanol was added to 1.4 g of the modified conductive composite obtained, and the mixture was dispersed in a high-pressure homogenizer to obtain a modified conductive composite dispersion. The modified conductive composite dispersion was then applied onto a PET film using a #8 bar coater, and dried at 150° C. for 1 minute to obtain a conductive film.

(Comparative Example 4)
300 g of methanol and 25 g of butylene oxide were added to 100 g of the PEDOT-PSS aqueous dispersion of Production Example 2. It was confirmed that the butylene oxide was dissolved in the PEDOT-PSS aqueous dispersion to form a homogeneous mixture. When this mixture was heated and stirred at 60°C for 4 hours and then allowed to stand at room temperature, a modified conductive composite was precipitated in the mixture. The precipitate in the mixture was filtered and washed with 100 g of water to obtain 1.3 g of a modified conductive composite.
The time required for filtering the precipitate is shown in Table 1.
198.7 g of isopropanol was added to 1.3 g of the modified conductive composite obtained, and the mixture was dispersed in a high-pressure homogenizer to obtain a modified conductive composite dispersion. The modified conductive composite dispersion was then applied onto a PET film using a #8 bar coater, and dried at 150° C. for 1 minute to obtain a conductive film.

Example 4
A coating material was obtained by adding 10 g of Artresin UN-904M (manufactured by Negami Chemical Industries, urethane acrylate, solid content 80%, methyl ethyl ketone solution), 30 g of pentaerythritol triacrylate, 2.5 g of hydroxyethyl acrylamide, 10 g of diacetone alcohol, and 1.6 g of Irgacure 184 (manufactured by BASF, photopolymerization initiator) to 50 g of the modified conductive composite dispersion obtained in Example 1. Next, the coating material was applied onto a PET film using a #8 bar coater, dried at 100° C. for 1 minute, and irradiated with 400 mJ of ultraviolet light to obtain a conductive film.

Example 5
A conductive film was obtained in the same manner as in Example 4, except that 50 g of the modified conductive complex dispersion obtained in Example 2 was used.

Example 6
A coating material was obtained by adding 1.5 g of KS-3703T (addition curable silicone, solid content 30%, toluene solution, manufactured by Shin-Etsu Chemical Co., Ltd.), 25.5 g of toluene, 60 g of methyl ethyl ketone, and 0.3 g of CAT-PL-50T (platinum catalyst, manufactured by Shin-Etsu Chemical Co., Ltd.) to 2.7 g of the modified conductive composite dispersion obtained in Example 3. Next, the coating material was applied onto a PET film using a #8 bar coater and dried at 150° C. for 1 minute to obtain a conductive film.

<Evaluation method>
[Surface resistance value]
The surface resistance of the conductive film in each example was measured using a resistivity meter (Hiresta manufactured by Mitsubishi Chemical Analytech Co., Ltd.) with an applied voltage of 10 V. The measurement results are shown in Table 1. In the table, "Ω/□" means ohms per square, "1.0E+06" means "1.0×10 ⁶ ", and so on. The smaller the surface resistance value (unit: Ω/□), the higher the conductivity.

[Peeling force]
For the conductive film of Example 6 containing silicone in the conductive layer, the peel strength was measured by the following method.
A 25 mm wide polyester adhesive tape (Nitto Denko Corporation, No. 31B) was attached to the surface of the conductive layer of the conductive film, and a load of 1976 Pa was applied to the adhesive tape and pressure treated at 25° C. for 20 hours. Next, in accordance with JIS Z0237, the adhesive tape attached to the conductive layer was peeled off at an angle of 180° (peel speed 0.3 m/min) using a tensile tester to measure the peel force (unit: N). A smaller peel force means higher releasability.

As described above, at the interface of the heterogeneous liquid phase in Examples 1 to 3 according to the present invention, the conductive complex contained in the aqueous phase reacted with the epoxy compound that did not dissolve in the aqueous phase and formed an organic phase, and a modified conductive complex was formed on the aqueous phase side.
On the other hand, in Comparative Examples 1 and 2, the epoxy compound constituting the organic phase of the heterogeneous liquid phase had a large number of carbon atoms, so the reaction with the conductive complex in the aqueous phase did not proceed, and no modified conductive complex was produced.
In Comparative Examples 3 and 4, an epoxy compound was added together with an alcohol solvent in an amount three times that of the aqueous conductive polymer dispersion, so that a heterogeneous liquid phase was not formed, and a homogeneous mixed liquid was obtained. In this mixed liquid, a modified conductive composite was formed, but the filtration time required to filter the modified conductive composite from the mixed liquid was much longer than in the Examples. This is presumably because the mixed liquid contains a large amount of alcohol solvent, so that the dispersibility of the modified conductive composite in the solvent is relatively good, and the modified conductive composite does not have a form suitable for filtering.
Moreover, the electrical conductivity of Examples 1 to 3 according to the present invention was superior to that of Comparative Examples 3 and 4.

Claims (11)

adding an epoxy compound having 7 or less carbon atoms to an aqueous dispersion of a conductive polymer, the aqueous dispersion containing a conductive complex including a π-conjugated conductive polymer and a polyanion, and an aqueous dispersion medium, to obtain a heterogeneous liquid phase in which at least a part of the epoxy compound is insoluble in the aqueous dispersion medium;
a mass ratio of (mass of aqueous phase/mass of organic phase composed of the epoxy compound) in the heterogeneous liquid phase is 1.5 or more and less than 10;
The method includes a step of reacting the conductive composite with the epoxy compound in the heterogeneous liquid phase, and isolating the modified conductive composite precipitated in the aqueous dispersion medium by filtration ,
The method for producing a modified conductive composite , wherein the content of water relative to the total mass of the aqueous dispersion medium is 90 mass % or more and 100 mass % or less. The method for producing the modified conductive composite according to claim 1 , further comprising a step of washing the separated modified conductive composite with water. The method for producing a modified conductive composite according to claim 1 or 2 , wherein the π-conjugated conductive polymer is poly(3,4-ethylenedioxythiophene). The method for producing a modified conductive composite according to any one of claims 1 to 3 , wherein the polyanion is polystyrene sulfonic acid. The method for producing a modified conductive composite according to any one of claims 1 to 4 , wherein the epoxy compound contains butylene oxide or butyl glycidyl ether. A modified conductive composite is obtained by the production method according to any one of claims 1 to 5 ,
A method for producing a modified conductive composite dispersion, comprising mixing the modified conductive composite with an organic solvent. The method for producing the modified conductive composite dispersion according to claim 6 , further comprising mixing a binder component. The method for producing a modified conductive composite dispersion according to claim 7 , wherein the binder component contains a compound that forms an acrylic resin after curing. The method for producing a modified conductive composite dispersion according to claim 7 , wherein the binder component comprises a cured silicone. The method for producing a modified conductive composite dispersion according to claim 9 , wherein the curable silicone comprises an addition-curable silicone. A method for producing a conductive film, comprising: coating at least one surface of a film substrate with a modified conductive composite dispersion obtained by the production method according to any one of claims 6 to 10 ; and drying the formed coating film.