WO2012173148A1 - Conductive polymer precursor, conductive polymer, and solid electrolyte capacitor - Google Patents

Abstract

The present invention relates to a conductive polymer precursor represented by general formula (1). (In formula (1), R¹ to R⁴ are each independently selected from among the group comprising a hydrogen atom, a straight chain or branched chain alkyl group having 1 to 24 carbon atoms, a straight chain or branched chain alkoxy group having 1 to 24 carbon atoms, an acidic group or a salt thereof, a hydroxyl group, a nitro group and a halogen atom; A is an acidic group or a salt thereof, and n is an integer between 1 and 20.)

Description

Conductive polymer precursor, conductive polymer, and solid electrolytic capacitor

The present invention relates to a conductive polymer precursor suitable as a precursor of a conductive polymer, a conductive polymer obtained by polymerizing the conductive polymer precursor, and a solid electrolytic capacitor including a solid electrolyte layer containing the conductive polymer. This application claims priority based on Japanese Patent Application No. 2011-132184 filed in Japan on June 14, 2011 and Japanese Patent Application No. 2012-110285 filed on May 14, 2012 in Japan. , The contents of which are incorporated herein.

As conductive polymers used in various applications, polyaniline-based, polythiophene-based, and polypyrrole-based conductive polymers are known.
In general, the conductivity (σ) of a conductive polymer depends on the carrier charge (q), the number of carriers (n), and the mobility (μ) between and within the molecular chains of the carrier, It is derived from the following formula (I).
σ = qnμ (I)

In the case of a polyaniline-based conductive polymer, the carrier charge (q) is an eigenvalue determined by the type of carrier. Therefore, in order to improve conductivity, the number of carriers (n) and mobility (μ) must be set. It is important to increase.
In order to increase the mobility (μ), it is considered effective to increase the molecular weight of the conductive polymer or reduce the proportion of impurities contained in the conductive polymer.
On the other hand, in order to increase the number (n) of carriers, it is considered effective to introduce an acidic group such as a sulfonic acid group or a carboxyl group and remove a base that inhibits dope.

As a polyaniline-based conductive polymer having an acidic group introduced therein, for example, a conductive polymer obtained by polymerizing a compound (II) shown below: 2-aminoanisole-4-sulfonic acid as a precursor has been proposed (Patent Literature). 1).

In addition, a solid electrolytic capacitor having a solid electrolyte layer containing a conductive polymer has a metal foil of a valve metal such as aluminum, tantalum, or niobium, or an anodized film of a porous molded body on the surface of a sintered metal body. A capacitor formed and having the anodic oxide coating as a dielectric. An electrolyte is in contact with the anodic oxide coating, and this electrolyte functions as a cathode for drawing an electrode from the anodic oxide coating.

Since the electrolyte as the cathode has a great influence on the electrical characteristics of the electrolytic capacitor, electrolytic capacitors employing various types of electrolytes have been proposed. In solid electrolytic capacitors, a conductive polymer such as polyethylenedioxythiophene (PEDOT) is widely used as a solid electrolyte. Further, by immersing the capacitor element in a mixed solution of an oxidant solution and a monomer solution, the capacitor element is impregnated with the oxidant and the monomer, and a polymerization reaction between the oxidant and the monomer is performed on the insulating film in the capacitor element. Methods for promoting and forming solid electrolytes are known.

Moreover, as a method for improving the conductive performance of the electrolyte, an oxidant and a dopant (conducting aid) are added to the monomer, and the monomer and the oxidant are directly reacted on the anodized film to form a solid electrolyte layer (conductive polymer layer). A chemical oxidative polymerization method is used to form. As its production method, a chemical oxidative polymerization method in which 3,4-ethylenedioxythiophene (EDOT), an oxidizing agent and a dopant are dissolved in an organic solvent and reacted on an anodic oxide film to form a conductive polymer layer (Patent Document) 2) has been proposed.

In addition, as a method of manufacturing an electrolytic capacitor with reduced equivalent series resistance (hereinafter abbreviated as ESR), a capacitor element is immersed in a solution containing a doping agent and then dried, and a monomer that becomes a conductive polymer by oxidation polymerization is used. A method of forming a solid electrolyte layer in the capacitor element by sequentially dropping and impregnating the capacitor element with an aqueous solution of an oxidant (Patent Document 3), or a conductivity containing a dopant agent having high electrical conductivity An electrolytic capacitor (Patent Document 4) impregnated with a polymer and an electrolytic solution has been proposed.

Also proposed is a method of forming a solid electrolyte layer by preparing a solution of a conductive polymer, impregnating the solution into an anodic oxide coating, drying and forming a coating (Patent Document 5).

Also, a method for improving the heat resistance by adding a basic compound to a conductive polymer solution has been proposed (Patent Document 6).

Japanese Unexamined Patent Publication No. 7-196791 Japanese Patent Laid-Open No. 02-15611 JP 2000-223364 A Japanese Patent Laid-Open No. 11-186110 JP 09-22833 A JP 2010-116441 A

By the way, the conductive polymer is used for various applications such as a capacitor. For example, when used for a capacitor, a conductive polymer is usually applied on a metal electrode and heat-treated at a predetermined temperature to form a conductive polymer layer (electrolyte layer).
However, although the conductive polymer described in Patent Document 1 has excellent conductivity, it does not satisfy the thermal stability. Therefore, when used in applications such as capacitors that include a heat treatment step in the manufacturing process, sufficient conductivity cannot be exhibited.

As for the solid electrolyte layer, in the above-described method of polymerizing the solid electrolyte on the anodic oxide coating, the conductive polymer layer is not easily formed up to the fine irregularities of the anodic oxide coating, and further a solid containing a dopant agent. The electrolyte layer has a problem that since the dopant agent easily escapes (de-dope) from the solid electrolyte layer in the electrolytic solution, the electrical conductivity of the solid electrolyte layer decreases and the ESR gradually increases.
On the other hand, the method of preparing a conductive polymer solution having an acidic group as a dopant in the molecule and forming a coating film in advance is a simpler manufacturing method than the method of polymerizing on an anodic oxide coating, The performance is not sufficient and has similar problems.
Also, the method of adding a basic compound to a conductive polymer is not sufficient in heat resistance for use in applications such as capacitors, and has the same problem.

The present invention has been made in view of the above circumstances, and has a high conductivity and a conductive polymer precursor suitable as a precursor of a conductive polymer excellent in thermal stability, and a high conductivity, An object of the present invention is to provide a conductive polymer excellent in thermal stability and a conductive composition containing the conductive polymer. Another object of the present invention is to provide a solid electrolytic capacitor having excellent heat resistance and low equivalent series resistance.

As a result of intensive studies, the present inventors have found that when an electrically conductive polymer into which an acidic group has been introduced is heated, the acidic group is eliminated, which causes a decrease in electrical conductivity.
Therefore, by using a soluble aniline-based conductive polymer having a repeating unit (also referred to as a conductive polymer precursor) in which an acidic group is introduced via an alkylene group having a specific carbon number, the conductivity is maintained while maintaining the conductivity. It has been found that the thermal stability of the polymer can be improved, and the present invention has been completed.

Furthermore, it has been found that a solid electrolytic capacitor having excellent heat resistance and low equivalent series resistance can be obtained by using a soluble aniline-based conductive polymer having the repeating unit.
In addition, the soluble aniline-based conductive polymer of the present invention has high solubility in water, an organic solvent, and a water-containing organic solvent, and does not require a doping step after film formation, thereby simplifying the method for manufacturing a capacitor.

The present invention has the following aspects.

The first aspect of the present invention is a conductive polymer precursor represented by the following general formula (1).

In formula (1), R ¹ to R ⁴ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, an acidic group Or a salt thereof, a hydroxyl group, a nitro group, and a halogen atom, A is an acidic group or a salt thereof, and n is an integer of 1-20.

In a second aspect of the present invention, the R ² is a hydrogen atom, and at least one of R ¹ , R ³ , and R ⁴ is a linear or branched alkoxy group having 1 to 24 carbon atoms. It is a conductive polymer precursor as described in 1 aspect.

In a third aspect of the present invention, R ² is a hydrogen atom, one of R ¹ , R ³ , and R ⁴ is a linear or branched alkoxy group having 1 to 24 carbon atoms, and the rest is a hydrogen atom The conductive polymer precursor according to the second aspect.

The fourth aspect of the present invention is a conductive polymer obtained by polymerizing the conductive polymer precursor according to any one of the first to third aspects.

The fifth aspect of the present invention is a conductive composition comprising an aniline conductive polymer (a) having a repeating unit represented by the following general formula (1-A) and a solvent (b).

In formula (1), R ¹ , R ³ and R ⁴ each independently represent a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, or a linear or branched alkoxy group having 1 to 24 carbon atoms. , An acidic group or a salt thereof, a hydroxyl group, a nitro group, and a halogen atom, A is an acidic group or a salt thereof, and n is an integer of 1 to 20.

The sixth aspect of the present invention is the conductive composition according to the fifth aspect, wherein at least one of R ¹ , R ³ and R ⁴ is a linear or branched alkoxy group having 1 to 24 carbon atoms. It is a thing.

A seventh aspect of the present invention is the fifth aspect, wherein ^one of R ¹ , R ³ , and R ⁴ is a linear or branched alkoxy group having 1 to 24 carbon atoms, and the remainder is a hydrogen atom. It is an electroconductive composition of description.

The eighth aspect of the present invention is the conductive composition according to any one of the fifth to seventh aspects, further including a basic compound (c).

9th aspect of this invention is a conductor which has a coating film formed from the conductive polymer as described in the said 4th aspect.

A tenth aspect of the present invention is a conductor having a coating film formed from the conductive composition according to any one of the fifth to seventh aspects.

The eleventh aspect of the present invention is a conductor having a coating film formed from the conductive composition according to the eighth aspect.

A twelfth aspect of the present invention is a solid electrolytic capacitor comprising a solid electrolyte layer containing the conductive polymer according to the fourth aspect on an anodized film formed on a valve action metal body.

A thirteenth aspect of the present invention comprises a solid electrolytic layer formed from the conductive composition according to any one of the fifth to seventh aspects on an anodized film formed on a valve action metal body. It is a solid electrolytic capacitor.

A fourteenth aspect of the present invention is a solid electrolytic capacitor comprising a solid electrolyte layer formed from the conductive composition according to the eighth aspect on an anodized film formed on a valve action metal body. is there.

The fifteenth aspect of the present invention is the following general formula (1):

(In the formula (1), R ¹ to R ⁴ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, an acidic group. A conductive polymer precursor of a compound selected from the group consisting of a group or a salt thereof, a hydroxyl group, a nitro group, and a halogen atom, wherein A is an acidic group or a salt thereof, and n is an integer of 1 to 20. As a use.

In a sixteenth aspect of the present invention, the conductive polymer precursor according to any one of the first to third aspects is polymerized in the presence of an oxidizing agent, and is represented by the following general formula (1-A). This is a method for producing an aniline-based conductive polymer (a) having a repeating unit.

In formula (1-A), R ¹ , R ³ and R ⁴ each independently represent a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkyl group having 1 to 24 carbon atoms. It is selected from the group consisting of an alkoxy group, an acidic group or a salt thereof, a hydroxyl group, a nitro group and a halogen atom, A is an acidic group or a salt thereof, and n is an integer of 1-20.

R ¹ in the formula (1) and the formula (1-A) is preferably a hydrogen atom, a linear or branched alkyl group having 1 to 10 carbon atoms, and a hydrogen atom, a linear chain having 1 to 3 carbon atoms or A branched alkyl group is more preferable, and a hydrogen atom is particularly preferable.

R ² in Formula (1) and Formula (1-A) is preferably a hydrogen atom, a linear or branched alkyl group having 1 to 10 carbon atoms, a hydrogen atom, a linear chain having 1 to 3 carbon atoms or A branched alkyl group is more preferable, and a hydrogen atom is particularly preferable.

R ³ in formula (1) and formula (1-A) is preferably a hydrogen atom, a linear or branched alkyl group having 1 to 10 carbon atoms, and a hydrogen atom, a linear chain having 1 to 3 carbon atoms or A branched alkyl group is more preferable, and a hydrogen atom is particularly preferable.

R ⁴ in Formula (1) and Formula (1-A) is a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, or a linear or branched alkoxy group having 1 to 10 carbon atoms. A linear or branched alkoxy group having 1 to 10 carbon atoms is more preferable, and a linear or branched alkoxy group having 1 to 5 carbon atoms is particularly preferable.

In Formula (1) and Formula (1-A), A is an acidic group or a salt thereof, preferably a carboxyl group, a sulfonic acid group or a salt thereof, and more preferably a sulfonic acid group or a salt thereof.

N in the formula (1) and the formula (1-A) is preferably 1 to 10, more preferably 1 to 6, further preferably 1 to 3, and particularly preferably 1 or 2.

The conductive polymer precursor of the present invention is suitable as a precursor of a conductive polymer having high conductivity and excellent thermal stability.
Moreover, the conductive polymer of this invention has high electroconductivity, and is excellent in thermal stability.
In addition, by using the conductive polymer and conductive composition of the present invention, a solid electrolytic capacitor having a high conductivity solid electrolytic layer with low equivalent series resistance and excellent heat resistance can be produced.

In Example 2 and Comparative Example 1, the heating temperature (° C.) is plotted on the X axis and the surface resistance value (Ω / □) of the test piece is plotted on the Y axis. FIG. 2 is a cross-sectional view schematically showing an example of the solid electrolytic capacitor of the present invention.

Hereinafter, the present invention will be described in detail.
[Conductive polymer precursor]
The conductive polymer precursor of the present invention is a compound represented by the following general formula (1) (hereinafter referred to as “compound (1)”).
In the present invention, “conductive” means that a coating film having a film thickness of about 0.1 μm has a surface resistance value of 10 ¹⁴ Ω / □ or less.

In formula (1), R ¹ to R ⁴ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, an acidic group Or it is chosen from the group which consists of the salt, a hydroxyl group, a nitro group, and a halogen atom.
Examples of the alkyl group include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, sec-butyl group, t-butyl group, pentyl group, hexyl group and the like.

Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, a sec-butoxy group, a t-butoxy group, a pentoxy group, and a hexoxy group.

Examples of acidic groups include sulfonic acid groups and carboxyl groups.
Each of these may be contained in an acid state (—SO ₃ H, —COOH) or may be contained in an ionic state.
Among these, a sulfonic acid group or a carboxyl group is preferable, and a sulfonic acid group is more preferable from the viewpoint that the affinity for water can be increased, and when a conductive polymer is obtained, higher conductivity can be expressed.
As the salt of an acidic group, at least one of an alkali metal salt, an alkaline earth metal salt, an ammonium salt, and a substituted ammonium salt of an acidic group is shown.

Examples of the alkali metal include lithium, sodium, and potassium.
Examples of the alkaline earth metal include magnesium and calcium.
Examples of substituted ammonium include alicyclic ammoniums, cyclic saturated ammoniums, and cyclic unsaturated ammoniums.
Examples of the aliphatic ammoniums include ammoniums represented by the following general formula (III).

In formula (III), R ⁵ to R ⁸ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
Specific examples of such fatty ammoniums include methylammonium, dimethylammonium, trimethylammonium, ethylammonium, diethylammonium, triethylammonium, methylethylammonium, diethylmethylammonium, dimethylethylammonium, propylammonium, dipropylammonium, Isopropyl ammonium, diisopropyl ammonium, butyl ammonium, dibutyl ammonium, methyl propyl ammonium, ethyl propyl ammonium, methyl isopropyl ammonium, ethyl isopropyl ammonium, methyl butyl ammonium, ethyl butyl ammonium, tetramethyl ammonium, tetramethylol ammonium, tetraethyl ammonium, tetra n- Chill ammonium, tetra sec- butyl ammonium, and the like can be exemplified tetra t- butyl ammonium. Among these, from the viewpoint of solubility, it is most preferable that one of R ⁵ to R ⁸ is a hydrogen atom, and the other three are alkyl groups having 1 to 4 carbon atoms, and then two of R ⁵ to R ⁸ are A hydrogen atom and the other two are preferably alkyl groups having 1 to 4 carbon atoms.

Examples of the cyclic saturated ammoniums include piperidinium, pyrrolidinium, morpholinium, piperazinium, and derivatives having these skeletons.
Examples of the cyclic unsaturated ammonium include pyridinium, α-picolinium, β-picolinium, γ-picolinium, quinolinium, isoquinolinium, pyrrolinium, and derivatives having these skeletons.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Moreover, in Formula (1), A is an acidic group or its salt.
Here, “acidic group” means a sulfonic acid group or a carboxyl group.
Examples of the acidic group and the acidic group salt include the acidic group and acidic group salts exemplified above in the description of R ¹ to R ⁴ . Among these, A is preferably a sulfonic acid group or a salt thereof from the viewpoint that the affinity for water can be increased, and when a conductive polymer is obtained, higher conductivity can be expressed.

In the formula (1), n is an integer of 1 to 20. When n is 1 or more, a conductive polymer excellent in thermal stability can be obtained.

N is preferably 1 to 10, more preferably 1 to 6, further preferably 1 to 3, and particularly preferably 1 or 2.

As the compound (1), from the viewpoint that the thermal stability of the conductive polymer is improved and the production of the compound (1) is easy, R ² is a hydrogen atom, and R ¹ , R ³ , and R ⁴ At least one is preferably a linear or branched alkoxy group having 1 to 24 carbon atoms. Among them, R ² is a hydrogen atom, and one of R ¹ , R ³ , and R ⁴ is 1 carbon atom. It is preferably a linear or branched alkoxy group of ˜24, with the remainder being a hydrogen atom.

Compound (1) can be produced, for example, by the following steps (a) and (b).
Step (a): A compound represented by the following general formula (2) (hereinafter referred to as “compound (2)”) is sulfonated or carboxylated to give a compound represented by the following general formula (3) (hereinafter referred to as “compound (2)”). , “Compound (3)”).
(B) Step: A step of obtaining compound (1) by reducing compound (3).

In the general formula ^{(3), R 1 ~ R} 4, A and n are the same as the general formula (1) of ^R 1 ^{~ R} 4, A and n. Further, D in the general formula (2) is a detachable substituent and may be any group that can be converted to A by the reaction in the step (a). Specifically, for example, a chlorine atom , Halogen atoms such as bromine atom and iodine atom, mesyl group, tosyl group and the like.

Hereinafter, each step will be described in detail. In the method shown below, among compounds (1), a compound in which A is an alkali metal salt, ammonium salt or substituted ammonium salt of a sulfonic acid group (hereinafter referred to as “compound (1-1)”), Alternatively, it is a method for producing a compound in which A is a sulfonic acid group (hereinafter referred to as “compound (1-2)”).
In the reaction formulas shown below, M is an alkali metal, ammonium, or substituted ammonium.

<Production of Compound (1-1)>
(Step (a))
The step (a) includes the following step (a-1).
Step (a-1): The compound (2) and the sulfonating agent (M ₂ SO ₃ ) are reacted in a solvent to give a compound represented by the following general formula (3-1) (hereinafter referred to as “compound ( 3-1) ").

The reaction ratio (mol ratio) between the compound (2) and the sulfonating agent is preferably 1: 0.5 to 1: 5. When there are too few sulfonating agents, it will become difficult to complete reaction. When there are too many sulfonating agents, it is necessary to remove the unreacted sulfonating agent, which requires labor and manufacturing costs.
The reaction temperature is preferably 0 ° C. or higher, and the reaction time is preferably 0.5 to 12 hours.

Examples of the sulfonating agent include sodium sulfite, potassium sulfite, lithium sulfite, ammonium sulfite, sodium hydrogen sulfite, and potassium hydrogen sulfite.
Examples of the solvent include alcohols such as water, methanol, ethanol and propanol; ethers such as tetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane and diisopropyl ether; amides such as dimethylformamide and dimethylacetamide. It is done. These solvents may be used alone or in combination of two or more.

((B) Process)
In the step (b), the compound (3-1) is reduced to obtain the compound (1-1).

The reaction conditions in the step (b) are not particularly limited as long as they are general reduction conditions for a nitro group. Specific examples include catalytic hydrogenation using a reducing agent such as palladium carbon and Raney nickel, and reduction using a reducing agent such as zinc powder and tin under acidic conditions.

<Production of Compound (1-2)>
(Step (a))
The step (a) has the following steps (a-1) and (a-2).
Step (a-1): A step of obtaining a compound (3-1) by reacting the compound (2) with a sulfonating agent in a solvent.
Step (a-2): A step of protonating the compound (3-1) to obtain a compound represented by the following general formula (3-2) (hereinafter referred to as “compound (3-2)”).

(A-1) Step:
The step (a-1) is the same as the step (a-1) included in the production step of the compound (1-1).

(A-2) Process:
The step (a-2) is a step of protonating the salt of the sulfonic acid group in the compound (3-1) to a sulfonic acid group, and the protonation conditions in the step (a-2) are general protonation conditions. The conditions are not particularly limited, but the reaction ratio (mol ratio) between the compound (3-1) and the reagent used for protonation (protonating agent) is preferably 1: 0.5 to 1:10. When there are too few protonating agents, it becomes difficult to complete the reaction. When there are too many protonating agents, it is necessary to remove unreacted protonating agents, which requires labor and manufacturing costs.
The reaction temperature is preferably 0 ° C. or higher, and the reaction time is preferably 0.5 to 12 hours.

Protonating agents include inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid and phosphoric acid; organic acids such as methanesulfonic acid and trifluoromethanesulfonic acid.

((B) Process)
In the step (b), the compound (3-2) is reduced to obtain the compound (1-2).

The step (b) is the same as the step (b) included in the production step of the compound (1-1).

In addition, as the compound (2) used in the step (a), a commercially available product or a synthetic product may be used. When a synthetic product is used as the compound (2), the compound (2) is obtained through, for example, the following step (c).
(C) Step: A step of obtaining a compound (2) by subjecting a compound represented by the following general formula (4) (hereinafter referred to as “compound (4)”) to halogenation, mesylation, or tosylation. .

Step (c) is a step of substituting the hydroxyl group (alcohol) in compound (4) with a substituent (D), and the reaction conditions in step (c) are general halogenation conditions and mesylation conditions for alcohol. Or any tosylation conditions.
In addition, as a reagent used in the step (c), when an alcohol is halogenated, thionyl chloride, sulfuryl chloride, phosphorus trichloride, phosphorus pentachloride, phosphorus tribromide, phosphorus pentabromide, hydrogen chloride, hydrogen bromide , Hydrogen iodide, N-chlorosuccinimide, N-bromosuccinimide and the like. Moreover, when mesylating alcohol, methanesulfonyl chloride etc. are mentioned. Moreover, when alcohol is tosylated, para-toluenesulfonyl chloride etc. are mentioned.

Of the compounds (2), R ⁴ is R ^{4 ′} (alkoxy group), R ¹ to R ³ are hydrogen atoms, and D is D ² (halogen atom) (hereinafter “compound”) (2-1) ") can also be obtained by, for example, haloalkylating a compound represented by the following general formula (5) (hereinafter referred to as" compound (5) ").

The reaction ratio (mol ratio) between the compound (5) and the reagent used for the haloalkylation (haloalkylating agent) is preferably 1: 0.5 to 1:10. When there are too few haloalkylating agents, it will become difficult to complete reaction. When there are too many haloalkylating agents, by-products are likely to be generated, and it is necessary to remove the by-products after the reaction, which requires labor and manufacturing costs.
The reaction temperature is preferably −10 ° C. or higher, and the reaction time is preferably 0.5 to 24 hours.

Examples of the haloalkylating agent include methoxymethyl chloride, methoxyethyl chloride, methoxypropyl chloride, a mixture of hydrogen chloride and formalin.

In the conductive polymer precursor of the present invention thus obtained, an acidic group or a salt thereof (corresponding to A in the compound (1)) is bonded to an aromatic ring via an alkylene group having a specific carbon number. .

By the way, since an acidic group has electron withdrawing property, the electron density on the unsaturated carbon atom bonded to the acidic group is lowered. As a result, when heated, the bond between the acidic group and the carbon atom is easily broken.
Therefore, in the case of a conductive polymer obtained by polymerizing a compound in which an acidic group is directly bonded to an aromatic ring, such as 2-aminoanisole-4-sulfonic acid, the acidic group and It is considered that the bond of the carbon atom is broken, the acidic group is eliminated, and the conductivity is lowered.

However, in the case of the conductive polymer precursor of the present invention, as described above, an acidic group or a salt thereof is bonded to an aromatic ring via an alkylene group. Therefore, the carbon atom on the aromatic ring bonded to the alkylene group is less affected by electron withdrawing than the case where the acidic group is directly bonded to the aromatic ring, and the decrease in electron density is reduced. Conceivable. Therefore, the conductive polymer using the conductive polymer precursor of the present invention can maintain the conductivity because the acidic group is not easily detached even by heat treatment. In particular, in the general formula (1), R ² is a hydrogen atom, and at least one of R ¹ , R ³ and R ⁴ is an alkoxy group, more preferably R ² is a hydrogen atom. If a conductive polymer precursor in which one of R ¹ , R ³ , and R ⁴ is an alkoxy group and the rest is a hydrogen atom, a conductive polymer that can exhibit higher conductivity can be obtained.
Therefore, the conductive polymer precursor of the present invention is suitable as a precursor (raw material) of a conductive polymer having high conductivity and excellent thermal stability.

[Conductive polymer (aniline-based conductive polymer (a))]
The conductive polymer of the present invention (also referred to as aniline-based conductive polymer (a)) is obtained by polymerizing an aniline-based monomer component containing the conductive polymer precursor of the present invention, and has the following general formula (1-A ).

In formula (1-A), R ¹ , R ³ and R ⁴ each independently represent a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkyl group having 1 to 24 carbon atoms. It is selected from the group consisting of an alkoxy group, an acidic group or a salt thereof, a hydroxyl group, a nitro group, and a halogen atom, A is an acidic group or a salt thereof, and n is an integer of 1-20.
In particular, from the viewpoint of conductivity and solubility, n is preferably 1 to 10, more preferably 1 to 5, and particularly preferably 1 to 3.
This is considered to be because the elimination of the acidic group due to heating can be suppressed by inserting a spacer between the acidic group and the aromatic ring.

The aniline-based conductive polymer contains the conductive polymer precursor of the present invention as an essential component, but is soluble, conductive as a structural unit (monomer component) other than that represented by the general formula (1-A). A group consisting of substituted or unsubstituted aniline (other aniline monomers), thiophene, pyrrole, phenylene, vinylene, other divalent unsaturated groups and divalent saturated groups, as long as the properties and properties are not affected. It may contain at least one structural unit (monomer component) selected from the above.
The content of the conductive polymer precursor is preferably 1 to 100% by mass, more preferably 10 to 100% by mass in 100% by mass of the aniline monomer component, and has high conductivity and thermal stability. It becomes easy to obtain an excellent conductive polymer.

The aniline-based conductive polymer of the present invention preferably contains 70% or more of the content of the acidic group with respect to the repeating unit of the general formula (1-A), that is, the aromatic ring, from the viewpoint of improving the solubility. % Or more is preferable, and especially 90% or more is preferable. Here, those having an acidic group content of 70% or less with respect to the aromatic ring are not preferable because of insufficient solubility in water. Further, the higher the content of acidic groups with respect to the aromatic ring, the better the solubility, which is suitable for capacitor production.
In addition, the conductive polymer precursor may be used alone, or two or more different conductive polymers may be mixed and used in an arbitrary ratio within the range corresponding to the general formula (1-A).

The weight average molecular weight of the aniline-based conductive polymer is preferably 3000 to 500,000, more preferably 5000 to 200,000, and more preferably 7000 to 10 in terms of sodium polystyrene sulfonate, from the viewpoint of conductivity, film formability and film strength. Many are particularly preferred.
Here, when the weight average molecular weight is 3000 or less, the solubility is excellent but the film formability and conductivity are insufficient. When the weight average molecular weight is 500,000 or more, the solubility and impregnation into the porous molded body are inferior. It is enough.
In addition, as the solid electrolytic capacitor has better performance such as frequency characteristics, a soluble conductive polymer having a conductivity of 0.01 S / cm or more, preferably 0.05 S / cm or more is used.

The other aniline monomer is not particularly limited as long as it is an aniline monomer copolymerizable with the conductive polymer precursor of the present invention. For example, aniline, methylaniline, dimethylaniline, trimethylaniline, tetramethyl Aniline, ethylaniline, diethylaniline, triethylaniline, tetraethylaniline, propylaniline, dipropylaniline, tripropylaniline, tetrapropylaniline, butylaniline, dibutylaniline, tributylaniline, tetrabutylaniline, methoxyaniline, dimethoxyaniline, trimethoxy Aniline, tetramethoxyaniline, ethoxyaniline, diethoxyaniline, triethoxyaniline, tetraethoxyaniline, bromoaniline, chloroaniline, aniline fluoride, shear Aniline, hydroxyaniline, nitroaniline, dibromoaniline, dichloroaniline, difluorinated aniline, dicyanoaniline, dihydroxyaniline, dinitroaniline, diaminobenzene, N-methylaniline, N-ethylaniline, Nn-propylaniline, N-iso -Propylaniline, N-butylaniline, aminobenzenesulfonic acid, aminobenzenedisulfonic acid, aminophenolsulfonic acid, aminophenoldisulfonic acid, methoxyanilinesulfonic acid, aminobenzoic acid, aminobenzenedicarboxylic acid, aminobenzenephosphoric acid, aminobenzene Diphosphoric acid, aminobenzenesulfonamide, aminobenzenethiol, aminobenzamide, acetotoluidine, aminoacetophenone, aminobenzenethiol, amino Chlorophenol, aminonaphthalene, aminonaphthalenesulfonic acid, aminonaphthalenecarboxylic acid, aminonaphthalenephosphoric acid, aminonitrophenol, aminophenyl, aminophenylphenol, aminoquinline, aminobenzotrifluoride, aminobenzyl alcohol, aminophenylboronic acid, amino Examples include cresol, aminoindole, and luminol.

The content of the other aniline monomer is preferably 0 to 99% by mass, more preferably 0 to 90% by mass in 100% by mass of the aniline monomer component, has high conductivity, and is thermally stable. It becomes easy to obtain a conductive polymer having excellent properties.

It does not specifically limit as a manufacturing method of the conductive polymer of this invention, Well-known manufacturing methods, such as the chemical polymerization method and electrolytic polymerization method by an oxidizing agent, can be used.
Hereinafter, an example of the manufacturing method of the conductive polymer of this invention is demonstrated concretely.

The conductive polymer of the present invention can be obtained, for example, by polymerizing the above aniline monomer component with an oxidizing agent in a polymerization solvent.
The aniline monomer used in the present invention has a sulfone group and / or a carboxyl group. Examples of such an acid group-substituted aniline monomer include an acid group-substituted aniline, an alkali metal salt thereof, and an alkaline earth metal. A compound selected from the group consisting of a salt, an ammonium salt, and a substituted ammonium salt is preferred.
In addition, as the acidic group-substituted aniline monomer, a compound represented by the general formula (1) is preferable in view of exhibiting excellent conductivity and improving water solubility.

<Oxidizing agent>
Examples of the oxidizing agent include peroxodisulfuric acids such as peroxodisulfuric acid, ammonium peroxodisulfate, sodium peroxodisulfate, and potassium peroxodisulfate; hydrogen peroxide.
These oxidizing agents may be used individually by 1 type, and 2 or more types may be mixed and used for them in arbitrary ratios.

The amount of the oxidizing agent used is preferably 1 to 5 mol, more preferably 1 to 3 mol, relative to 1 mol of the aniline monomer component. When the amount of the oxidizing agent used is within the above range, the conductive polymer can be sufficiently polymerized and the main chain can be oxidized sufficiently.
It is also effective to use a transition metal compound such as iron or copper in combination with an oxidizing agent as a catalyst.

<Polymerization solvent>
Examples of the polymerization solvent include water and organic solvents. Examples of the organic solvent include alcohols such as methanol, ethanol, isopropyl alcohol, propyl alcohol and butanol; ketones such as acetone and ethyl isobutyl ketone; ethylene glycols such as ethylene glycol and ethylene glycol methyl ether; propylene glycol and propylene glycol Propylene glycols such as methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether and propylene glycol propyl ether; Amides such as N, N-dimethylformamide and N, N-dimethylacetamide; N-methylpyrrolidone, N-ethylpyrrolidone and the like Pyrrolidones and the like.
As the polymerization solvent, water or a mixed solvent of water and an organic solvent is preferable.

<Polymerization process>
A conductive polymer is obtained by chemically oxidatively polymerizing the above aniline monomer component with an oxidizing agent in a polymerization solvent (polymerization step).
Specifically, an aniline monomer component solution (precursor solution) is dropped into an oxidant solution, an oxidizer solution is dropped into an aniline monomer component solution, an aniline simple substance is added to a reaction vessel or the like. By various methods, such as a method of dropping a monomer component solution and an oxidant solution simultaneously, a method of continuously supplying an aniline monomer component solution and an oxidant solution to a reaction vessel or the like, and a method of polymerizing in an extruded flow, A conductive polymer is obtained.
In the polymerization, the above-described polymerization solvent can be used.

In the polymerization, a protonic acid may be added to the reaction system.
Examples of the protic acid include mineral acids such as hydrochloric acid, nitric acid, sulfuric acid, and borofluoric acid, super strong acids such as trifluoromethanesulfonic acid, and organic substances such as methanesulfonic acid, dodecylbenzenesulfonic acid, toluenesulfonic acid, and camphorsulfonic acid. Examples thereof include sulfonic acids, and polymer acids such as polystyrene sulfonic acid, polyacrylic acid, polyvinyl sulfonic acid, poly-2-methylpropane-2-acrylamide sulfonic acid, and the like.

The internal temperature of the polymerization reaction is preferably 50 ° C. or less, more preferably −15 to 50 ° C., and further preferably −10 to 20 ° C. In particular, if the internal temperature of the polymerization reaction is 20 ° C. or lower, it is possible to suppress a decrease in conductivity due to the progress of side reactions and changes in the redox structure of the main chain. Further, when the internal temperature of the polymerization reaction is −15 ° C. or higher, a sufficient reaction rate can be maintained and the reaction time can be shortened.

<Purification process>
The conductive polymer is obtained in the state of a polymer solution dissolved or dispersed in a solvent. The conductive polymer may be used for various applications as it is after removing the solvent, but the polymer solution may contain unreacted monomers (aniline monomer components), oligomers, impurities, and the like. Therefore, it is preferable to use the conductive polymer after purification (purification step).
Examples of the method for purifying the conductive polymer include a cleaning method using a solvent, a membrane filtration method, and a cation exchange method.

The conductive polymer thus obtained can be obtained by polymerizing an aniline monomer component containing the conductive polymer precursor of the present invention. As described above, the conductive polymer precursor of the present invention is a monomer in which an acidic group or a salt thereof is bonded to an aromatic ring via an alkylene group having 1 to 20 carbon atoms. Salt is not easily released. Therefore, the conductive polymer of the present invention has high conductivity and is excellent in thermal stability. Therefore, conductivity can be maintained even after heat treatment.

The conductive polymer of the present invention is considered to have a phenylenediamine structure (reduced type) and a quinodiimine structure (oxidized type) represented by the following general formula (6).

In formula (6), R ⁹ to R ²⁴ each independently represent a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, an acidic group A group or a salt thereof, a hydroxyl group, a nitro group, and a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), and at least one of R ¹¹ , R ¹⁵ , R ¹⁹ , and R ²³ Is — (CH ₂ ) _n —A. Here, A is an acidic group or a salt thereof, and n is an integer of 1-20. Y represents the degree of polymerization.

This phenylenediamine structure (reduced type) and quinodiimine structure (oxidized type) can be reversibly converted at an arbitrary ratio by oxidation or reduction. The ratio (x) of the phenylenediamine structure to the quinodiimine structure is preferably in the range of 0.2 <x <0.8 from the viewpoint of conductivity and solubility, and more preferably 0.3 <x <0.7.

The conductive polymer of the present invention can be dissolved in simple water, water containing a base and a basic salt, water containing an acid, a solvent such as methanol, ethanol, iso-propanol, or a mixture thereof. Excellent workability.

The conductive polymer of the present invention forms a conductor by a simple method such as spray coating, dip coating, roll coating, gravure coating, reverse coating, roll brushing, air knife coating, curtain coating, etc. can do.

The composition comprising the conductive polymer of the present invention as a main component includes various antistatic agents, capacitors, batteries, EMI shields, chemical sensors, display elements, nonlinear materials, anticorrosion, adhesives, fibers, antistatic paints, anticorrosion. It can be applied to paints, electrodeposition paints, plating primers, electrostatic coating bases, cathodic protection, and battery storage capacity improvement.
Among these, since the conductive polymer of the present invention is excellent in thermal stability and can maintain conductivity even after heat treatment, it is suitable for applications such as a capacitor including a heat treatment step in the production process.

The aniline-based conductive polymer (a) obtained by the above production method may form a salt with a cation, which is a factor that impedes conductivity, and it is desirable to remove these cations. .

In order to remove impurities such as cations, a method of bringing the conductive polymer dispersion or solution into contact with a cation exchange resin is preferred. When the conductive polymer is subjected to impurity removal with a cation exchange resin, it is used in a state dispersed or dissolved in a solvent.

Solvents include alcohols such as water, methanol, ethanol, isopropanol, propanol, and butanol; ketones such as acetone, methyl ethyl ketone, ethyl isobutyl ketone, methyl isobutyl ketone; ethylene glycol, ethylene glycol methyl ether, ethylene glycol mono-n- Ethylene glycols such as propyl ether; propylene glycols such as propylene glycol, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether and propylene glycol propyl ether; amides such as dimethylformamide and dimethylacetamide; N-methylpyrrolidone; Pyrrolidones such as N-ethylpyrrolidone; methyl lactate, ethyl lactate, β-methoxy Methylbutyric acid, hydroxy esters such as α- hydroxy methyl isobutyrate, and a mixture of these preferred.

The concentration when the conductive polymer is dispersed or dissolved in the solvent is preferably from 0.1 to 20% by mass, more preferably from 0.1 to 10% by mass, from the viewpoint of industrial properties and purification efficiency.

Commercially available products can be used as the cation exchange resin, and for example, strong acid type cation exchange resins such as “Amberlite” manufactured by Organo Corporation are preferred.
The form of the cation exchange resin is not particularly limited, and various forms can be used. Examples thereof include spherical fine particles, membranes, and fibers.
The amount of the cation exchange resin with respect to the conductive polymer is preferably 1 to 20 parts by mass, more preferably 5 to 15 parts by mass with respect to 1 part by mass of the conductive polymer from the viewpoint of industrial properties and purification efficiency.

As a method of contacting the dispersion or solution of the conductive polymer with the cation exchange resin, the dispersion or solution of the conductive polymer and the cation exchange resin are placed in a container, and the mixture is stirred or rotated to exchange the cation. The method of making it contact with resin is mentioned.
In addition, the column is filled with a cation exchange resin, and the dispersion or solution of the conductive polymer is preferably passed at a flow rate of SV = 0.01 to 20, more preferably SV = 0.2 to 5, A method of performing cation exchange treatment may be used.
Here, space velocity SV (1 / hr) = flow rate (m ³ / hr) / filter medium amount (volume: m ³ ).
From the viewpoint of purification efficiency, the time for which the conductive polymer dispersion or solution is brought into contact with the cation exchange resin is preferably 0.1 hour or longer, and more preferably 0.5 hour or longer.
The upper limit of the contact time is not particularly limited, and may be appropriately set in accordance with conditions such as the concentration of the dispersion or eluent of the conductive polymer, the amount of the cation exchange resin, and the contact temperature described later.

The temperature at which the conductive polymer dispersion or solution is brought into contact with the cation exchange resin is preferably 10 to 50 ° C., more preferably 10 to 30 ° C., from an industrial viewpoint.

The conductive polymer purified in this way exhibits a superior conductivity because low molecular weight substances such as oligomers and monomers and impurities such as cations are sufficiently removed.

<Solvent (b)>
The solvent (b) used in the conductive composition is not particularly limited as long as it is a solvent that dissolves the conductive polymer (a), but water and / or a water-soluble organic solvent is preferable.
Specific examples of water-soluble organic solvents include alcohols such as acetonitrile, methanol, ethanol, isopropanol, n-propanol, and n-butanol, ketones such as acetone, methyl ethyl ketone, ethyl isobutyl ketone, and methyl isobutyl ketone, ethylene glycol, Ethylene glycols such as ethylene glycol methyl ether, propylene glycols such as propylene glycol and propylene glycol methyl ether, amides such as dimethylformamide and dimethylacetamide, pyrrolidones such as N-methylpyrrolidone and N-ethylpyrrolidone, and lactic acid Examples thereof include hydroxy esters such as methyl, ethyl lactate, methyl β-methoxyisobutyrate and methyl α-hydroxyisobutyrate.
Among these, alcohols, acetone, acetonitrile, dimethylformamide, dimethylacetamide and the like are preferable from an industrial viewpoint.

The concentration of the conductive composition is preferably from 0.1 to 20% by mass, more preferably from 0.5 to 10% by mass from the viewpoint of industrial properties and purification efficiency. A solid electrolyte layer having a sufficient thickness can be formed as the concentration is higher. On the other hand, the lower the concentration, the more the agglomeration of the conductive polymer and compound in the solution can be suppressed, the higher the viscosity becomes, and the fine irregularities of the anodized film can be easily impregnated.

<Basic compound (c)>
Heat resistance improves by containing the basic compound (c) in the electrically conductive composition of this invention. The reason is considered that the basic compound (c) prevents decomposition of the conductive polymer (a). Examples of the basic compound (c) include inorganic bases such as sodium hydroxide, potassium hydroxide, lithium hydroxide and calcium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrahydroxide Organic hydroxides such as butylammonium, primary alkylamines such as methylamine, ethylamine, propylamine, butylamine, pentylamine and hexylamine, primary amines such as benzylamine and aniline, dimethylamine, diethylamine and dipropylamine Secondary alkylamines such as dibutylamine, dipentylamine and dihexylamine, secondary amines such as methylaniline, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, Tertiary alkylamines such as silamine, tertiary amines such as dimethylaniline, alcohol amines such as 2-aminoethanol, diethanolamine, and triethanolamine, α-picoline, β-picoline, γ-picoline, pyridine, pyreridine, etc. Examples include heterocyclic amine water, benzylamine, methoxyethylamine, aminopyridine, hydroxymethylpyridine, pyridinol, ethylenediamine, and ammonia. Among these, sodium hydroxide or ammonia is preferable. Any one of these basic compounds may be used alone, or two or more thereof may be mixed and used.

The basic compound (c) is an acidic group-substituted aniline or the like, and remains in the conductive composition that is used when the monomer that is a raw material of the conductive polymer (a) is oxidatively polymerized in a solution. In addition, the same or different basic compound may be added to the conductive composition.
In addition, the addition amount of the basic compound (c) is preferably 0.01 to 2.0 mol with respect to 1 mol of the repeating unit of the conductive polymer (a) from the viewpoint of conductivity and / or heat resistance. 1 to 1.5 mol is more preferable, 0.15 to 1.0 mol is more preferable, and 0.2 to 0.65 mol is particularly preferable.

<Solid electrolyte layer (conductive polymer layer)>
In the present invention, the solid electrolyte layer is formed from a conductive composition obtained by mixing the aniline conductive polymer and a solvent.

As a method for forming a solid electrolyte layer, a dip coating method, a brush coating method, a spin coating method, a casting method, a micro gravure coating method, a gravure coating method, a bar coating method, a roll coating method, a wire bar coating method, a spray coating method, Examples thereof include a flow coating method, a screen method printing, a flexographic printing method, an offset printing method, and an ink jet printing method. Among these, the dip coating method is preferable because it is easy to operate.
When the conductive composition is applied by the dip coating method, the immersion time in the conductive composition is preferably 1 to 30 minutes from the viewpoint of workability. In addition, when dip-coating, it is also effective to dip at the time of depressurization to return to normal pressure, or to pressurize at the time of dip.

As a drying method after forming the solid electrolyte layer, heat drying is preferable, but for example, air drying, spinning and physical drying may be used.
The drying conditions are determined by the types of the conductive polymer (a) and the solvent (b). Usually, the drying temperature is preferably 50 ° C. to 190 ° C. from the viewpoint of drying properties, and the drying time is 1 to 120 minutes is preferred.

<Method for manufacturing wound solid electrolytic capacitor>
In the embodiment of the present invention, the wound solid electrolytic capacitor is manufactured by a known technique in addition to the solid electrolyte layer forming step.
For example, after the surface layer vicinity of the aluminum foil is made porous by etching, an anodic oxide film is formed by anodic oxidation, the solid charge including the solid electrolyte layer according to the present embodiment is formed, and then the cathode portion is formed. The wound solid electrolytic capacitor according to the present embodiment can be obtained by connecting external terminals to the anode part and the cathode part and providing an exterior.
The anodized film is formed by anodizing an electrode (valve action metal body) made of a metal material (film forming metal) such as aluminum, tantalum, niobium or nickel. An anodized film formed by anodizing a porous valve metal body reflects the surface state of the valve metal body, and has a concavo-convex structure with a fine surface. The period of the unevenness is usually about 200 nm or less, although it depends on the type of valve action metal body.
In addition, the depth of the recesses (pores) forming the irregularities is not easily determined because it is particularly dependent on the type of valve action metal body, but when using aluminum, for example, the depth of the recesses is It is about several tens of nm to 1 μm.

<Manufacturing method of multilayer solid electrolytic capacitor>
In the embodiment of the present invention, the multilayer solid electrolytic capacitor is manufactured by a known technique in addition to the solid electrolyte layer forming step.
For example, after the surface layer vicinity of the valve action metal body such as an aluminum foil is made porous by etching, an anodized film is formed by anodization. Next, after forming a solid electrolyte layer on the anodized film, this is immersed in a graphite solution, or a graphite solution is applied to form a graphite layer on the solid electrolyte layer, and a metal layer is further formed on the graphite layer. Form. Furthermore, the multilayer solid electrolytic capacitor according to the present embodiment can be obtained by connecting and externally connecting external terminals to the cathode part and the anode part.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.
In addition, the measurement / evaluation method in an Example and a comparative example is as follows.

(NMR measurement)
^The compound was identified by measuring ¹ H-NMR spectrum. This measurement was performed by using FT-NMR (“JNM-GX270” manufactured by JEOL Ltd.) and dissolving a measurement sample in deuterated dimethyl sulfoxide to a concentration of about 5% by mass. The sample was placed in a 5 mmφ test tube, and the measurement was performed at a measurement temperature of 25 ° C., a measurement frequency of 270 MHz, and a single pulse mode with 64 integrations.

(Measurement of mass average molecular weight of conductive polymer)
First, in a mixed solvent in which water (ultra pure water) and methanol are mixed so that the volume ratio is water: methanol = 8: 2, sodium carbonate and sodium hydrogen carbonate, each solid content concentration is 20 mmol / L, The eluent was prepared by adding 30 mmol / L. The resulting eluent had a pH of 10.8 at 25 ° C. In this eluent, the conductive polymer was dissolved so that the solid content concentration was 0.1% by mass to prepare a test solution.
About the obtained test solution, molecular weight distribution was measured using the polymeric material evaluation apparatus provided with the gel permeation chromatograph.
Subsequently, about the obtained chromatogram, the retention time was converted into the molecular weight (M) of polystyrene sulfonate conversion, and the mass average molecular weight of the conductive polymer was obtained.

(Evaluation of thermal stability and conductivity)
A conductive polymer solution is applied on a glass substrate using a spin coater, heated on a hot plate at a predetermined temperature for 5 minutes, and a test piece having a coating film (film thickness: about 100 nm) formed on the glass substrate is obtained. Obtained.
The surface resistance value of the obtained test piece was measured by attaching a two-probe probe to a resistivity meter (manufactured by Mitsubishi Chemical Analytech Co., Ltd., “Hiresta IP”).

(Capacitance measurement / Equivalent series resistance measurement)
The electric capacity and equivalent series resistance were measured by using an LCR meter (E4980A Precision LCR meter manufactured by Agilent Technologies) at an electric frequency of 120 Hz and an equivalent series resistance at 100 kHz.

(Repeating unit of conductive polymer (monomer unit) [mol])
With respect to the conductive polymer powder, the weight of the powder was divided by the molecular weight of the polymer repeating unit to determine the repeating unit (monomer unit) [mol] of the conductive polymer.
In the case of a dispersion or solution of a conductive polymer, the solution or dispersion is dried at 100 ° C. for 1 hour, and the remaining solid is used as a conductive polymer powder. Similarly, the conductive polymer is a repeating unit (monomer unit). [Mol] was determined.

[Example 1]
<Synthesis of conductive polymer precursor>
Step (c): Synthesis of 3-nitro-4-methoxybenzyl chloride Thionyl chloride was added to a solution of 4.8 g (26.2 mmol) of 3-nitro-4-methoxybenzyl alcohol (4-1) in 48 mL of methylene chloride. 6.2 g (52.4 mmol) was added. The solution was stirred for 20 hours at room temperature, 30 mL of toluene was added, and the mixture was concentrated under reduced pressure. The obtained solid was suspended in hexane, then filtered, and the residue was dried to obtain 5.13 g of 3-nitro-4-methoxybenzyl chloride (2-2) (yield 97.2). %).

Step (a): Synthesis of 3-nitro-4-methoxyphenylmethanesulfonic acid 3.0 mL (14.9 mmol) of 3-nitro-4-methoxybenzyl chloride (2-2) and 3.48 g of sodium sulfite in 6 mL of water ( 9.21 mmol) was mixed and heated to reflux at 100 ° C. for 3 hours (step (a-1)).
After cooling the reaction solution, water was added to the precipitated solid (3-3) to dissolve it, and 6.18 g of 50% by mass sulfuric acid was added thereto. This solution was concentrated under reduced pressure, 80 mL of ethanol was further added, and the mixture was concentrated again under reduced pressure. The obtained solid was suspended in methanol and then filtered under reduced pressure. The filtrate was concentrated under reduced pressure to obtain 2.64 g of 3-nitro-4-methoxyphenylmethanesulfonic acid (3-4) (step (a-2)) (yield 71.7%).

Assignment of the ¹ H-NMR spectrum of the obtained 3-nitro-4-methoxyphenylmethanesulfonic acid (3-4) is shown below.
¹ H-NMR (270 MHz in DMSO): δ 7.79 (s, 1 H), δ 7.58 (d, 1 H, J = 8.37 Hz), δ 7.27 (d, 1 H, J = 8.37 Hz), δ 3 .90 (s, 3H), δ 3.73 (s, 2H).

Step (b): Synthesis of 3-amino-4-methoxyphenylmethanesulfonic acid 2.2 g (8.9 mmol) of 3-nitro-4-methoxyphenylmethanesulfonic acid (3-4) was dissolved in 27.7 mL of methanol. Then, 0.22 g of palladium carbon (Pd—C) was added thereto. The reaction vessel was purged with hydrogen and stirred at room temperature (25 ° C.) for 3 hours. The reaction solution was filtered, and the filtrate was concentrated under reduced pressure to give 3-amino-4-methoxyphenylmethanesulfonic acid (1-3) 1.95 g was obtained (90% yield).

Assignment of ¹ H-NMR spectrum of the obtained 3-amino-4-methoxyphenylmethanesulfonic acid (1-3) is shown below.
¹ H-NMR (270 MHz in DMSO): δ 6.65 (d, 1H, J = 9.99 Hz), δ 6.64 (s, 1H), δ 6.44 (d, 1H, J = 9.99 Hz), δ3 .72 (s, 3H), δ 3.51 (s, 2H).

[Example 2]
<Production of conductive polymer (a)>
2.24 g (100 mmol) of ammonium peroxodisulfate (molecular weight 224.20) was stirred and dissolved in 25 g of water to prepare an oxidant solution.
Separately, an aniline monomer component consisting of 2.17 g (100 mmol) of 3-amino-4-methoxyphenylmethanesulfonic acid (molecular weight 217.24) was dissolved in 25 g of water, and an aniline monomer component solution (precursor) Solution) was prepared.
While the oxidant solution was cooled in an ice bath and stirred, the precursor solution was added dropwise over 1 hour. After completion of the addition, stirring was continued for 2 hours under ice cooling. Subsequently, stirring was continued at room temperature (25 ° C.) for 2 hours to conduct a polymerization reaction, thereby obtaining a black precipitate.
The resulting black precipitate was filtered, and the residue was washed with water and then dried under reduced pressure to obtain 1.5 g of a conductive polymer (poly (3-amino-4-methoxyphenylmethanesulfonic acid)) (a). . The obtained poly (3-amino-4-methoxyphenylmethanesulfonic acid) had a weight average molecular weight of 25,000.

The obtained poly (3-amino-4-methoxyphenylmethanesulfonic acid) (a) was dissolved in 0.2 mol / L ammonia water to prepare a conductive polymer solution.
Using this conductive polymer solution, thermal stability and conductivity were evaluated.
A total of seven test pieces were prepared by changing the heating temperature, and the surface resistance value of each test piece was measured. From the obtained results, a graph was prepared by plotting the heating temperature (° C.) on the X axis and the surface resistance value (Ω / □) of the test piece on the Y axis. The graph is shown in FIG.

[Comparative Example 1]
<Synthesis of Conductive Polymer Precursor (a ′)>
2.24 g (100 mmol) of ammonium peroxodisulfate (molecular weight 224.20) was stirred and dissolved in 10 g of a mixed solvent of water and acetonitrile (volume ratio = 1: 1) to prepare an oxidant solution.
Separately, 2.03 g (100 mmol) of 2-aminoanisole-4-sulfonic acid (molecular weight 203.22) commercially available from Tokyo Chemical Industry Co., Ltd. and 1.1 g of triethylamine were mixed with 10 g of water and acetonitrile (volume). The solution was dissolved in a ratio = 1: 1) to prepare a precursor solution.
Except for using these oxidant solution and precursor solution, the polymerization reaction was carried out in the same manner as in Example 1. The resulting black precipitate was filtered, the residue was washed with water, dried under reduced pressure, and electrically conductive. 1.2 g of a functional polymer (poly (2-aminoanisole-4-sulfonic acid)) (a ′) was obtained. The obtained poly (2-aminoanisole-4-sulfonic acid) had a mass average molecular weight of 23,000.
The obtained poly (2-aminoanisole-4-sulfonic acid) was dissolved in water at room temperature (25 ° C.) and ion exchanged with a strongly acidic ion exchange resin (manufactured by Organo Corporation, “Amberlite IR-120B”). This was treated to obtain a conductive polymer solution (a′-2).
Using the obtained conductive polymer solution, thermal stability and electrical conductivity were evaluated in the same manner as in Example 2. The results are shown in FIG.

As is clear from FIG. 1, the conductive polymer obtained in Example 2 has a stable surface resistance value and can maintain high conductivity even when the heating temperature is increased. Therefore, it was shown that the conductive polymer obtained from the conductive polymer precursor of the present invention has excellent thermal stability and high conductivity even when heat-treated at a high temperature of 200 ° C. or higher.
On the other hand, a conductive polymer (Comparative Example 1) obtained from a monomer in which an acidic group or a salt thereof is bonded to an aromatic ring without an alkylene group has a higher surface resistance as the heating temperature is higher, and the conductivity is higher. Declined.

[Example 3]
<Manufacture of conductive composition>
5 parts by mass of the obtained conductive polymer (a) was dissolved in 95 parts by mass of water at room temperature to obtain a conductive polymer solution (a-1).
“Room temperature” means 25 ° C.
An acidic cation exchange resin (manufactured by Organo Co., Ltd., “Amberlite”) is packed into a column so as to be 50 parts by mass with respect to 100 parts by mass of the obtained aqueous conductive polymer solution (a-1). Then, the conductive polymer solution (a-1) was passed at a flow rate of SV = 8 to perform a cation exchange treatment to obtain a purified conductive polymer solution (a-2).
In the obtained conductive polymer solution (a-2), the proportion of the conductive polymer was 4.5% by mass (4.7 parts by mass with respect to 100 parts by mass of the solvent). Further, the content of the basic compounds (triethylamine and ammonia) forming the salt contained in the conductive polymer solution (a-2) was 0.1% by mass or less.

[Example 4]
A conductive composition solution was prepared using the conductive polymer solution (a-2) obtained in Example 3. After immersing the conductive composition solution in the anodic oxide coating of the aluminum capacitor for 2 minutes, it is dried by a hot air dryer at 120 ° C. for 30 minutes, and further subjected to heat treatment at 180 ° C. for 120 minutes, and then on the anodic oxide coating. A solid electrolyte layer was formed. Table 1 also shows the equivalent series resistance of the obtained wound solid electrolytic capacitor.

[Comparative Example 2]
Except for using the conductive polymer solution (a′-2) obtained in Comparative Example 1, the same procedure as in Example 4 was performed, and the equivalent series resistance of the obtained solid electrolytic capacitor is shown in Table 1.

[Example 5]
A solid electrolyte layer was formed in the same manner as in Example 4 except that diethanolamine was added as a basic compound to the polymer solution (a-2) obtained in Example 3, and the resulting wound solid was obtained. Table 1 also shows the equivalent series resistance of the electrolytic capacitor.

[Example 6]
Further, a solid electrolyte layer was formed by the same method as in Example 4 except that lithium hydroxide was added as a basic compound to the polymer solution (a-2) obtained in Example 3. Table 1 also shows the equivalent series resistance of the wound solid electrolytic capacitor.

Evaluation of heat resistance in Table 1 was performed according to the following criteria.
A: Compared to the equivalent series resistance value when heat-dried at 120 ° C. for 30 minutes, the increase in equivalent series resistance value when heated at 180 ° C. for 120 minutes is less than 5 times.
B: Compared with the equivalent series resistance value when heated at 120 ° C. for 30 minutes, the increase in equivalent series resistance value when heated at 180 ° C. for 120 minutes is 5 times or more.

From Table 1, Example 4 using the conductive polymer solution (a-2) containing the conductive polymer (a) suppressed the increase in equivalent series resistance even after the heat treatment, and was excellent after the heat treatment. It showed heat resistance.
Moreover, even if Example 5 and Example 6 which respectively added diethanolamine and lithium hydroxide as a basic compound (c) were heat-processed, the increase in equivalent series resistance was suppressed.
On the other hand, unlike the conductive polymer (a), Comparative Example 2 using a conductive polymer solution (a′-2) containing a conductive high polymer (a ′) in which an acidic group is directly bonded to an aromatic ring is As a result, the equivalent series resistance significantly increased and the heat resistance was poor after the heat treatment.

The conductive polymer precursor of the present invention is particularly suitable as a precursor of a conductive polymer used for applications such as capacitors including a heat treatment step in the production process, and is practically useful.
The conductive polymer of the present invention can also be suitably used for applications such as capacitors that include a heat treatment step in the production process.

20 Solid Electrolytic Capacitor 21 Anode 22 Cathode 23 Separator 24 External Terminal

Claims (15)

1. A conductive polymer precursor represented by the following general formula (1).
   

   

   In formula (1), R ¹ to R ⁴ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, an acidic group Or a salt thereof, a hydroxyl group, a nitro group, and a halogen atom, A is an acidic group or a salt thereof, and n is an integer of 1-20.
2. The conductive polymer precursor according to claim 1, wherein R ² is a hydrogen atom, and at least one of R ¹ , R ³ and R ⁴ is a linear or branched alkoxy group having 1 to 24 carbon atoms. .
3. The R ² is a hydrogen atom, one of R ¹ , R ³ , and R ⁴ is a linear or branched alkoxy group having 1 to 24 carbon atoms, and the remainder is a hydrogen atom. Conductive polymer precursor.
4. A conductive polymer obtained by polymerizing the conductive polymer precursor according to any one of claims 1 to 3.
5. A conductive composition comprising an aniline-based conductive polymer (a) having a repeating unit represented by the following general formula (1-A) and a solvent (b).
   

   

   In formula (1), R ¹ , R ³ and R ⁴ each independently represent a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, or a linear or branched alkoxy group having 1 to 24 carbon atoms. , An acidic group or a salt thereof, a hydroxyl group, a nitro group, and a halogen atom, A is an acidic group or a salt thereof, and n is an integer of 1 to 20.
6. The conductive composition according to claim 5, wherein R ² is a hydrogen atom, and at least one of R ¹ , R ³ and R ⁴ is a linear or branched alkoxy group having 1 to 24 carbon atoms.
7. 6. The conductive composition according to claim 5, wherein ^{one of} R ¹ , R ³ and R ⁴ is a linear or branched alkoxy group having 1 to 24 carbon atoms, and the rest is a hydrogen atom.
8. The conductive composition according to any one of claims 5 to 7, further comprising a basic compound (c).
9. A conductor having a coating film formed from the conductive polymer according to claim 4.
10. A conductor having a coating film formed from the conductive composition according to any one of claims 5 to 7.
11. A conductor having a coating film formed from the conductive composition according to claim 8.
12. A solid electrolytic capacitor comprising a solid electrolyte layer containing the conductive polymer according to claim 4 on an anodized film formed on a valve action metal body.
13. A solid electrolytic capacitor comprising a solid electrolyte layer formed of the conductive composition according to any one of claims 5 to 7 on an anodized film formed on a valve action metal body.
14. A solid electrolytic capacitor comprising a solid electrolyte layer formed from the conductive composition according to claim 8 on an anodized film formed on a valve action metal body.
15. An aniline-based conductive polymer having a repeating unit represented by the following general formula (1-A) by polymerizing the conductive polymer precursor according to any one of claims 1 to 3 in the presence of an oxidizing agent ( Method for producing a).
    

    

    In formula (1-A), R ¹ , R ³ and R ⁴ each independently represent a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkyl group having 1 to 24 carbon atoms. It is selected from the group consisting of an alkoxy group, an acidic group or a salt thereof, a hydroxyl group, a nitro group and a halogen atom, A is an acidic group or a salt thereof, and n is an integer of 1-20.

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