JP2012097274A - Conductive coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive coating film excellent in any of conductivity, thermal stability and film strength.SOLUTION: The conductive coating film is formed by coating a conductive polymer solution and has a surface resistance of 5,000 Ω or lower. The conductive polymer solution includes a π-conjugated conductive polymer, a polyanion, a (meth)acrylamide compound having one or more of an acrylamide group and/or a methacrylamide group, and a solvent. The polyanion is any of polystyrenesulfonic acid, polyisoprene sulfonic acid, polyacrylic acid ethyl sulfonate and polyacrylic acid butyl sulfonate. The content of the (meth)acrylamide compound is 2 to 50 mol equivalents to the polyanion.

Description

  The present invention relates to a conductive coating film containing a π-conjugated conductive polymer.

In recent years, conductive materials have been developed in which electron-donating compounds and electron-accepting compounds (dopants) are added (doping) to π-conjugated conductive polymers such as polypyrrole, polythiophene, polyacetylene, polyparaphenylene, and polyaniline. Applications are expanding.
In particular, attention has been paid to the transparency of the π-conjugated conductive polymer, and an alternative to an ITO film (indium-tin-oxide) that is currently widely used as a transparent conductor is being studied.
However, since the π-conjugated conductive polymer itself does not dissolve in any solvent, the processability is low and it is difficult to form a coating film or to perform patterning.

Therefore, as a method of forming a conductive coating film containing a π-conjugated conductive polymer, an oxidant, a vinyl chloride copolymer, and a precursor monomer that forms a π-conjugated conductive polymer are used as solvents. There has been proposed a method in which a precursor monomer is polymerized while being dissolved and coated on a substrate and controlling an oxidation potential with a solvent (see Patent Document 1).
Further, in the presence of polystyrene sulfonic acid (polyanion) having a molecular weight of 2,000 to 500,000, 3,4-dialkoxythiophene is chemically oxidatively polymerized using an oxidizing agent to produce poly (3,4-dialkoxy). A method of producing a (thiophene) solution and applying the solution to a substrate has been proposed (see Patent Document 2).

  By the way, as an electroconductive coating film, not only high electroconductivity but a thing with high thermal stability and film | membrane intensity | strength is calculated | required from a practical point. As a method for enhancing the thermal stability, a method in which a compound having a structure similar to a sulfonated substance that can be used as an antioxidant is mixed with a precursor monomer as a dopant and a thermal stabilizer and polymerized is proposed. (See Patent Document 3).

Japanese Patent Laid-Open No. 5-186619 Japanese Patent No. 2636968 Japanese Patent No. 2546617

However, in the method described in Patent Document 1, since the solvent is limited depending on the type of substrate, the precursor monomer is limited, and a π-conjugated conductive polymer having high conductivity cannot be obtained. In addition, the inclusion of a vinyl chloride copolymer, which is an insulating resin, is one factor that prevents high conductivity.
In the method described in Patent Document 2, the π-conjugated conductive polymer can be easily dispersed in water, but there is a problem that high conductivity is difficult to obtain because the amount of non-conductive polyanion increases.
The method described in Patent Document 3 has a problem that although the thermal stability is excellent, it is difficult to obtain the solvent solubility of the π-conjugated conductive polymer.
Moreover, the film strength could not be improved by the methods of Patent Documents 1 to 3.
In other words, a conductive polymer solution that is excellent in solvent solubility of a π-conjugated conductive polymer can be obtained in addition to the formation of a conductive coating film that is excellent in conductivity, thermal stability, and film strength. It was not done.
An object of this invention is to provide the electroconductive coating film which was excellent in all of electroconductivity, thermal stability, and film | membrane intensity | strength.

  The conductive coating film of the present invention is a conductive coating film formed by applying a conductive polymer solution, and has a surface resistance of 5000Ω or less, and the conductive polymer solution is a π-conjugated conductive material. A polymer, a polyanion, a (meth) acrylamide compound having at least one acrylamide group and / or methacrylamide group, and a solvent, wherein the polyanion is polystyrene sulfonic acid, polyisoprene sulfonic acid, polyethyl acrylate It is either sulfonic acid or polybutyl acrylate, and the content of the (meth) acrylamide compound is 2 to 50 molar equivalents relative to the polyanion.

  The conductive coating film of the present invention is excellent in all of conductivity, thermal stability and film strength. Such a conductive coating film can replace a conductive film of an inorganic material such as an ITO film, and can form a pattern by a method such as photolithography.

(Conductive polymer solution)
[Π-conjugated conductive polymer]
As the π-conjugated conductive polymer, any organic polymer having a main chain composed of a π-conjugated system can be used. Examples thereof include polypyrroles, polythiophenes, polyacetylenes, polyphenylenes, polyphenylene vinylenes, polyanilines, polyacenes, polythiophene vinylenes, and copolymers thereof. From the viewpoint of easy polymerization and stability in air, polypyrroles, polythiophenes and polyanilines are preferred.
Even if the π-conjugated conductive polymer remains unsubstituted, sufficient conductivity can be obtained. However, in order to further increase the conductivity, an alkyl group, a carboxyl group, a sulfo group, an alkoxyl group, a hydroxyl group, a cyano group It is preferable to introduce a functional group such as a group into the π-conjugated conductive polymer.

  Specific examples of such π-conjugated conductive polymers include polypyrrole, poly (N-methylpyrrole), poly (3-methylpyrrole), poly (3-ethylpyrrole), and 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), poly (3-methyl-4-hexyloxypyrrole), poly (3-methyl-4-hexyloxypyrrole), 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), poly (3-iodothiophene), poly (3-cyanothiophene), poly (3 -Phenylthiophene), poly (3,4-dimethylthiophene), poly (3,4-dibuty) Ruthiophene), poly (3-hydroxythiophene), poly (3-methoxythiophene), poly (3-ethoxythiophene), poly (3-butoxythiophene), poly (3-hexyloxythiophene), poly (3-heptyl) Oxythiophene), poly (3-octyloxythiophene), poly (3-decyloxythiophene), poly (3-dodecyloxythiophene), 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-dihexyl) Oxythiophene), poly (3,4-diheptyloxythiophene), poly (3 4-dioctyloxythiophene), poly (3,4-didecyloxythiophene), poly (3,4-didodecyloxythiophene), poly (3,4-ethylenedioxythiophene), poly (3,4-propylene) Dioxythiophene), poly (3,4-butenedioxythiophene), poly (3-methyl-4-methoxythiophene), poly (3-methyl-4-ethoxythiophene), poly (3-carboxythiophene), poly (3-methyl-4-carboxythiophene), poly (3-methyl-4-carboxyethylthiophene), poly (3-methyl-4-carboxybutylthiophene), polyaniline, poly (2-methylaniline), poly (3 -Isobutylaniline), poly (2-anilinesulfonic acid), poly (3-anilinesulfonic acid), etc. It is below.

Among these, one or two selected from polypyrrole, polythiophene, poly (N-methylpyrrole), poly (3-methylthiophene), poly (3-methoxythiophene), and poly (3,4-ethylenedioxythiophene) A (co) polymer consisting of seeds is preferably used from the viewpoint of resistance and reactivity. Furthermore, polypyrrole and poly (3,4-ethylenedioxythiophene) are more preferable because they have higher conductivity and improved heat resistance.
Moreover, in terms of excellent transparency, poly (3-methoxythiophene), poly (3,4-ethylenedioxythiophene), and polythienothiophene are preferable.
In addition, alkyl-substituted compounds such as poly (N-methylpyrrole) and poly (3-methylthiophene) are preferable because solvent solubility and compatibility and dispersibility when a hydrophobic resin is added are improved. Further, among the alkyl groups of the alkyl-substituted compound, a methyl group is preferable because it prevents a decrease in conductivity.

  The content of the π-conjugated conductive polymer in the conductive polymer solution is preferably 0.01 to 10% by mass.

[Polyanion]
The polyanion is a homopolymer or copolymer selected from substituted or unsubstituted polyalkylene, substituted or unsubstituted polyalkenylene, substituted or unsubstituted polyimide, substituted or unsubstituted polyamide, substituted or unsubstituted polyester And having a structural unit having an anionic group. Moreover, you may have a structural unit which does not have an anion group as needed.
The polyanion not only solubilizes the π-conjugated conductive polymer in a solvent, but also functions as a dopant for the π-conjugated conductive polymer.

  Here, polyalkylene is a polymer whose main chain is composed of repeating methylene. For example, polyethylene, polypropylene, polybutene, polypentene, polyhexene, polyvinyl alcohol, polyvinylphenol, poly (3,3,3-trifluoropropylene), polyacrylonitrile, polyacrylate, polystyrene and the like can be mentioned.

Polyalkenylene is a polymer composed of structural units containing one or more unsaturated bonds (vinyl groups) in the main chain. Among these, substituted or unsubstituted butenylene is preferable because of the interaction between the unsaturated bond and the π-conjugated conductive polymer and the ease of synthesis using substituted or unsubstituted butadiene as a starting material.
Specific examples of polyalkenylene include propenylene, 1-methylpropenylene, 1-butylpropenylene, 1-decylpropenylene, 1-cyanopropenylene, 1-phenylpropenylene, 1-hydroxypropenylene, 1-butenylene, 1-methyl-1-butenylene, 1-ethyl-1-butenylene, 1-octyl-1-butenylene, 1-pentadecyl-1-butenylene, 2-methyl-1-butenylene, 2-ethyl-1-butenylene, 2- Butyl-1-butenylene, 2-hexyl-1-butenylene, 2-octyl-1-butenylene, 2-decyl-1-butenylene, 2-dodecyl-1-butenylene, 2-phenyl-1-butenylene, 2-butenylene, 1-methyl-2-butenylene, 1-ethyl-2-butenylene, 1-octyl-2-butenylene 1-pentadecyl-2-butenylene, 2-methyl-2-butenylene, 2-ethyl-2-butenylene, 2-butyl-2-butenylene, 2-hexyl-2-butenylene, 2-octyl-2-butenylene, 2- Decyl-2-butenylene, 2-dodecyl-2-butenylene, 2-phenyl-2-butenylene, 2-propylenephenyl-2-butenylene, 3-methyl-2-butenylene, 3-ethyl-2-butenylene, 3-butyl 2-butenylene, 3-hexyl-2-butenylene, 3-octyl-2-butenylene, 3-decyl-2-butenylene, 3-dodecyl-2-butenylene, 3-phenyl-2-butenylene, 3-propylenephenyl- 2-butenylene, 2-pentenylene, 4-propyl-2-pentenylene, 4-butyl-2-pentenylene, 4-he Selected from sil-2-pentenylene, 4-cyano-2-pentenylene, 3-methyl-2-pentenylene, 4-ethyl-2-pentenylene, 3-phenyl-2-pentenylene, 4-hydroxy-2-pentenylene, hexenylene, etc. And polymers containing one or more structural units.

As polyimide, pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, benzophenonetetracarboxylic dianhydride, 2,2 ′, 3,3′-tetracarboxydiphenyl ether dianhydride, 2,2 ′-[ Examples include polyimides from anhydrides such as 4,4′-di (dicarboxyphenyloxy) phenyl] propane dianhydride and diamines such as oxydiamine, paraphenylenediamine, metaphenylenediamine, and benzophenonediamine.
Examples of the polyamide include polyamide 6, polyamide 6,6, polyamide 6,10 and the like.
Examples of the polyester include polyethylene terephthalate and polybutylene terephthalate.

When the polyanion has a substituent, examples of the substituent include an alkyl group, a hydroxyl group, an amino group, a cyano group, a phenyl group, a phenol group, an ester group, an alkoxyl group, and a carbonyl group. In view of solubility in a solvent, heat resistance, compatibility with a resin, and the like, an alkyl group, a hydroxyl group, a phenol group, and an ester group are preferable.
Alkyl groups can increase solubility and dispersibility in polar or nonpolar solvents, compatibility and dispersibility in resins, etc., and hydroxyl groups form hydrogen bonds with other hydrogen atoms and the like. It can be made easy and the solubility in an organic solvent, the compatibility with a resin, the dispersibility, and the adhesiveness can be increased. In addition, the cyano group and the hydroxyphenyl group can increase the compatibility and solubility in the polar resin, and can also increase the heat resistance.
Among the above substituents, an alkyl group, a hydroxyl group, an ester group, and a cyano group are preferable.

Examples of the alkyl group include chain alkyl groups such as methyl, ethyl, propyl, butyl, isobutyl, t-butyl, pentyl, hexyl, octyl, decyl, and dodecyl, and cycloalkyl groups such as cyclopropyl, cyclopentyl, and cyclohexyl. . In consideration of solubility in an organic solvent, dispersibility in a resin, steric hindrance, and the like, an alkyl group having 1 to 12 carbon atoms is more preferable.
Examples of the hydroxyl group include a hydroxyl group directly bonded to the main chain of the polyanion or a hydroxyl group bonded via another functional group. Examples of other functional groups include an alkyl group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an amide group, and an imide group. Hydroxyl groups are substituted at the ends or in these functional groups. In these, the hydroxyl group couple | bonded with the terminal of the C1-C6 alkyl group couple | bonded with the principal chain is more preferable from the compatibility to resin and the solubility to an organic solvent.
Examples of the ester group include an alkyl ester group directly bonded to the main chain of the polyanion, an aromatic ester group, and an alkyl ester group or an aromatic ester group having another functional group interposed therebetween.
The cyano group includes a cyano group directly bonded to the main chain of the polyanion, a cyano group bonded to the terminal of the alkyl group having 1 to 7 carbon atoms bonded to the main chain of the polyanion, and 2 to 2 carbon atoms bonded to the main chain of the polyanion. And a cyano group bonded to the terminal of 7 alkenyl group.

  The anion group of the polyanion may be a functional group capable of undergoing chemical oxidation doping to the π-conjugated conductive polymer. Among them, from the viewpoint of ease of production and stability, a monosubstituted sulfate group, A monosubstituted phosphate group, a phosphate group, a carboxyl group, a sulfo group and the like are preferable. Furthermore, a sulfo group and a monosubstituted sulfate group are more preferable from the viewpoint of the doping effect of the functional group on the π-conjugated conductive polymer.

Specific examples of polyanions include polyvinyl sulfonic acid, polystyrene sulfonic acid, polyallyl sulfonic acid, polyacrylic acid ethyl sulfonic acid, polyacrylic acid butyl sulfonic acid, poly (2-acrylamido-2-methylpropane sulfonic acid), polyisoprene. Sulfonic acid, polyvinyl carboxylic acid, polystyrene carboxylic acid, polyallyl carboxylic acid, polyacryl carboxylic acid, polymethacryl carboxylic acid, poly (2-acrylamido-2-methylpropane carboxylic acid), polyisoprene carboxylic acid, polyacrylic acid, etc. Can be mentioned.
These homopolymers may be sufficient and 2 or more types of copolymers may be sufficient.
Among these, polystyrene sulfonic acid, polyisoprene sulfonic acid, polyacrylic acid ethyl sulfonic acid, and polyacrylic acid butyl sulfonic acid are preferable. These polyanions can mitigate thermal decomposition of the π-conjugated conductive polymer.

  The degree of polymerization of the polyanion is preferably in the range of 10 to 100,000 monomer units, and more preferably in the range of 50 to 10,000 from the viewpoint of solvent solubility and conductivity.

  The content of the polyanion in the conductive polymer solution is preferably in the range of 0.1 to 10 mol and more preferably in the range of 1 to 7 mol with respect to 1 mol of the π-conjugated conductive polymer. preferable. When the polyanion content is less than 0.1 mol, the doping effect on the π-conjugated conductive polymer tends to be weak, and the conductivity may be insufficient. In addition, the dispersibility and solubility in the solvent are reduced, making it difficult to obtain a uniform dispersion. On the other hand, when the polyanion content is more than 10 mol, the content of the π-conjugated conductive polymer in the conductive polymer solution decreases, and it is difficult to obtain sufficient conductivity.

  In a conductive polymer solution, a π-conjugated conductive polymer and a polyanion often form a complex by chemical bonding. A preferable combination of the π-conjugated conductive polymer and the polyanion forming the composite has higher thermal stability and transparency of the coating film. Therefore, the π-conjugated conductive polymer is poly (3,4). -Ethylenedioxythiophene), poly (3-methoxythiophene), or polythienothiophene, and the polyanion is preferably polystyrene sulfonic acid.

[(Meth) acrylamide compound]
(Meth) acrylamide compound, an acrylamide group _{(CH 2 = CH-CO-} NR- (R is H or any substituent)) and / or methacrylamide group _{(CH 2 = C (CH 3} ) -CO-NR- (R is H or an arbitrary substituent))).
Specifically, N-methylacrylamide, N-methylmethacrylamide, N-ethylacrylamide, N-ethylmethacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N , N-diethylmethacrylamide, 2-hydroxyethylacrylamide, 2-hydroxyethylmethacrylamide, N-methylolacrylamide, N-methylolmethacrylamide and the like.

  The content of the (meth) acrylamide compound in the conductive polymer solution is preferably 0.001 to 95% by mass. When the content of the (meth) acrylamide compound in the conductive polymer solution is 0.001% by mass or more, the conductivity, thermal stability, and film strength can be further improved. However, if it exceeds 95% by mass, the proportion of the amount of the non-conductive (meth) acrylamide compound is increased, and the conductivity tends to be lowered, which is not preferable.

  The (meth) acrylamide compound is preferably contained in an amount of 0.001 to 10,000 molar equivalents relative to the polyanion, and more preferably 2 to 50 molar equivalents. When the content of the (meth) acrylamide compound is 0.001 molar equivalent or more with respect to the polyanion, film strength and thermal stability can be sufficiently secured. If it is 10,000 molar equivalents or less, since an excess (meth) acrylamide compound is not included, the fall of electroconductivity can be prevented reliably.

[solvent]
The solvent is not particularly limited. For example, water, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylene phosphortriamide, N-vinylpyrrolidone, N- Polar solvents such as vinylformamide, N-vinylacetamide, phenols such as cresol, phenol, xylenol, alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, glycerin, diglycerin, D-glucose, D-glucitol, isoprene glycol, butanediol, 1,5-penta Polyols such as diol, 1,6-hexanediol, 1,9-nonanediol and neopentyl glycol, ketones such as acetone and methyl ethyl ketone, hydrocarbons such as hexane, benzene and toluene, formic acid and acetic acid Carboxylic acids such as, carbonate compounds such as ethylene carbonate and propylene carbonate, ether compounds such as dioxane and diethyl ether, chain ethers such as ethylene glycol dialkyl ether, propylene glycol dialkyl ether, polyethylene glycol dialkyl ether, polypropylene glycol dialkyl ether, Heterocyclic compounds such as 3-methyl-2-oxazolidinone, acetonitrile, glutarodinitrile, methoxyacetonitrile, propionitrile, benzonitrile, etc. Nitrile compounds, and the like. These solvents may be used alone, as a mixture of two or more kinds, or as a mixture with other solvents.

[Dopant]
In the conductive polymer solution, a dopant other than the polyanion may be added in order to improve the conductivity of the π-conjugated conductive polymer.
Examples of other dopants include halogen compounds, Lewis acids, proton acids, and the like. Specifically, organic acids such as organic carboxylic acids and organic sulfonic acids, organic cyano compounds, fullerenes, hydrogenated fullerenes, fullerene hydroxides, Examples thereof include carboxylic acid fullerene and sulfonic acid fullerene.

Examples of organic acids include alkylbenzene sulfonic acid, alkyl naphthalene sulfonic acid, alkyl naphthalene disulfonic acid, naphthalene sulfonic acid formalin polycondensate, melamine sulfonic acid formalin polycondensate, naphthalene disulfonic acid, naphthalene trisulfonic acid, dinaphthylmethane disulfonic acid, Anthraquinone sulfonic acid, anthraquinone disulfonic acid, anthracene sulfonic acid, pyrene sulfonic acid, acetic acid, oxalic acid, benzoic acid, phthalic acid, maleic acid, fumaric acid, malonic acid and the like can be mentioned. These metal salts can also be used.
As the organic cyano compound, a compound containing two or more cyano groups in a conjugated bond can be used. Examples include tetracyanoethylene, tetracyanoethylene oxide, tetracyanobenzene, dichlorodicyanobenzoquinone (DDQ), tetracyanoquinodimethane, and tetracyanoazanaphthalene.

[Other ingredients]
In addition to the above-mentioned components, the conductive polymer solution includes pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, diester, in order to improve film strength and environmental resistance. Polyfunctional acrylates or polyfunctional methacrylates such as pentaerythritol triacrylate and dipentaerythritol tetraacrylate, silane coupling agents such as epoxy silane and vinyl silane, crosslinkable resins such as epoxy resins, vinyl resins and polyisocyanates, 2,6-di -Tert-butyl-p-cresol, 2,5-di-tert-butylhydroquinone, 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2-mercaptobe Antioxidants such as benzimidazole, ultraviolet absorbers and the like may be included.

[Production method]
Next, an example of a method for producing a conductive polymer solution will be described.
In the method for producing a conductive polymer solution of this example, first, a precursor monomer that forms a π-conjugated conductive polymer is chemically oxidatively polymerized in a solvent in the presence of a polyanion to obtain a π-conjugated conductive polymer. And a complex of polyanion is formed. When the complex is formed, the anion group of the polyanion forms a salt with the π-conjugated conductive polymer as the main chain of the π-conjugated conductive polymer grows. The main chain grows along the polyanion. Therefore, the obtained π-conjugated conductive polymer and polyanion become a complex in which an infinite number of salts are formed. In this composite, 1 unit of anionic group forms a salt with respect to 3 units of monomer of π-conjugated conductive polymer, and several short-grown π-conjugated conductive polymers follow along a long polyanion. It is presumed that a salt is formed.
Next, a (meth) acrylamide compound is added to the solution containing the complex to obtain a conductive polymer solution.

In the conductive polymer solution described above, the (meth) acrylamide compound is polymerized so that the complex of the π-conjugated conductive polymer and the polyanion can be pseudo-crosslinked, and the intermolecular distance is shortened to converge. be able to. Therefore, the activation energy required for hopping in electron transfer between π-conjugated conductive polymers is small, and the conductivity of the coating film is increased (specifically, the electrical conductivity is 100 S / cm or more). Is considered.) Therefore, even if the amount of polyanions that solubilize the π-conjugated conductive polymer is increased, high conductivity can be maintained, so that solvent solubility can be increased.
Moreover, the thermal stability and film strength of the coating film are improved by the crosslinking of the composite.

(Conductive coating)
The conductive coating film of the present invention is formed by applying the above-described conductive polymer solution and polymerizing a (meth) acrylamide compound.
Examples of the method for applying the conductive polymer solution include known methods such as coating, dipping, and spraying.
Examples of the substrate on which the conductive polymer solution is applied include a glass plate and a plastic film.

In the polymerization, polymerization by heat or radiation can be applied. For example, various polymerization methods such as a radical polymerization method, a thermal polymerization method, a photo radical polymerization method, a plasma polymerization, and a cationic polymerization method can be applied.
When radical polymerization is applied in the polymerization, examples of polymerization initiators include azo compounds such as azobisisobutyronitrile, peroxides such as benzoyl peroxide, diacyl peroxides, peroxyesters, hydroperoxides, etc. Is used. These polymerization initiators are preferably contained in advance in the conductive polymer solution.

  In the photo radical polymerization method, polymerization is performed using a carbonyl compound, a sulfur compound, an organic peroxide, an azo compound, or the like as a polymerization initiator. Specifically, benzophenone, 4,4-bis (dimethylamine) benzophenone, 4-methoxy-4′-dimethylaminobenzophenone, 4,4′-dimethoxybenzophenone, 4-dimethylaminobenzophenone, 4-dimethylaminoacetophenone , Anthraquinone, 2-t-butylanthraquinone, 2-methylanthraquinone, 2,4-diethylthioxanthone, fluorenone, accdrine, Michler's ketone, xanthone, thioxanthone, 2-ethylanthraquinone, acetophenone, trichloroacetophenone, 2-hydroxy-2-methyl- Propiophenone, 1-hydroxycyclohexyl phenyl ketone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin phenyl ether Ether, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, benzyl, methylbenzoylformate, 1-phenyl-1,2-propanedione-2- (o-benzoyl) oxime, 2, Examples include 4,6-trimethylbenzoyldiphenylphosphine oxide, tetramethylthiuram, dithiocarbamate, benzoyl peroxide, N-laurylpyridium azide, and polymethylphenylsilane. These photopolymerization initiators are preferably contained in the conductive polymer solution in advance.

In the case of photo radical polymerization, a sensitizer for improving photo sensitivity may be added. Specific examples of the sensitizer include 2,5-bis (4′-diethylaminobenzal) cyclopentanone, 2,6-bis (4′-dimethylaminobenzal) cyclohexanone, 2,6-bis (4 '-Diethylaminobenzal) -4-methylcyclohexanone, 4,4'-bis (dimethylamino) chalcone, 4,4'-bis (diethylamino) chalcone, 2- (p-dimethylaminophenylvinylene) benzothiazole, 2- (P-dimethylaminophenylvinylene) -isonaphthothiazole, 3,3′-carbonyl-bis (7-diethylaminocoumarin) and the like. One or more of these sensitizers can be used.
Some sensitizers also act as photopolymerization initiators.
In plasma polymerization, plasma is irradiated for a short time, receives energy from electron bombardment of the plasma, performs fragmentation and rearrangement, and then generates a polymer by recombination of radicals.

Since the conductive coating film described above is formed from the above conductive polymer solution, all of the conductivity, thermal stability, and film strength are excellent. In particular, the surface resistance can be 5 × 10 ³ Ω or less and the total light transmittance can be 80% or more. If the surface resistance of the conductive coating film is 5 × 10 ³ Ω or less and the total light transmittance is 80% or more, the requirement for high conductivity and high transparency can be sufficiently met.

(Preparation Example 1)
14.2 g (0.1 mol) of 3,4-ethylenedioxythiophene was mixed with a solution of 27.5 g (0.15 mol) of polystyrene sulfonic acid dissolved in 2000 ml of ion-exchanged water.
While maintaining this mixed liquid at 20 ° C., stirring was performed to prepare 8.0 g (0.02 mol) of ferric sulfate oxidation catalyst solution of 29.64 g (0.13 mol) of ammonium persulfate dissolved in 200 ml of ion-exchanged water. Slowly added and stirred for 3 hours to react.
The obtained reaction solution was dialyzed to remove unreacted monomers and oxidants to obtain about 1.5% by mass of a blue polystyrene sulfonic acid doped poly (3,4-ethylenedioxythiophene) solution. This was designated as Complex Solution 1.

(Preparation Example 2)
6.6 g (0.1 mol) of pyrrole and 27.5 g (0.15 mol) of polystyrene sulfonic acid dissolved in 2000 ml of ion exchange water were mixed.
While maintaining this mixed liquid at 20 ° C., stirring was performed to prepare 8.0 g (0.02 mol) of ferric sulfate oxidation catalyst solution of 29.64 g (0.13 mol) of ammonium persulfate dissolved in 200 ml of ion exchange water. Slowly added and allowed to react with stirring for 2 hours.
2000 ml of ion-exchanged water was added to the resulting reaction solution, and about 2000 ml of solution was removed using an ultrafiltration method. This operation was repeated three times.
The obtained reaction solution was dialyzed to remove unreacted monomers and oxidant to obtain about 1.5% by mass of a blue polystyrene sulfonic acid doped polypyrrole solution. This was designated as Complex Solution 2.

Example 1
In 100 ml of the complex solution 1, 3.48 g (6 molar equivalents relative to polystyrene sulfonic acid) of 2-hydroxyethyl acrylamide and 0.104 g (3 mass% relative to 2-hydroxyethyl acrylamide) of 4,4 '-Dimethoxybenzophenone was added and dispersed uniformly to obtain a conductive polymer solution. The obtained conductive polymer solution was applied onto a polyethylene terephthalate film having a thickness of 85 μm (T630E manufactured by Mitsubishi Polyester) using a # 12 bar coat. Thereafter, the film was dried in an oven at 100 ° C. and irradiated with an integrated light amount of 500 mJ / cm ² by a UV exposure machine to form a conductive coating film.
The conductivity, thermal stability, transparency, and film strength of the conductive coating film were evaluated as follows. The results are shown in Table 1.

Surface resistance (Ω): The surface resistance of the conductive coating film was measured using a Loresta (manufactured by Dia Instruments).
High-temperature surface resistance maintenance ratio (%): The surface resistance R _25B of the conductive coating film at a temperature of 25 ° C. is measured, and after the measurement, the conductive coating film is left in an environment at a temperature of 85 ° C. for 300 hours. The coating film was returned to a temperature of 25 ° C., and the surface resistance R _25A was measured. And it computed from the following formula.
High temperature surface resistance maintenance ratio (%) = 100 × R _25B / R _25A
High humidity surface resistance maintenance ratio (%): The surface resistance R _25B of the conductive coating film at a temperature of 25 ° C. is measured, and the conductive coating film after measurement is left in an environment of a temperature of 60 ° C. and a relative humidity of 95% for 300 hours. Then, the conductive coating film was returned to a temperature of 25 ° C., and the surface resistance R _25C was measured. And it computed from the following formula.
High humidity surface resistance maintenance rate (%) = 100 × R _25B / R _25C
Thermal stability can be evaluated by the high temperature surface resistance maintenance ratio and the high humidity surface resistance maintenance ratio.

  Total light transmittance (%), haze (%): A haze meter (manufactured by BYK Gardner, Haze guard plus (according to JIS K 7361-1)) was used.

The film strength was evaluated as follows. That is, the surface of the conductive coating film was wiped 10 times while applying a load of 50 mm in diameter and 200 g to the nonwoven fabric (Adclean Wiper F1 type). And the abrasion surface resistance maintenance factor (%) was calculated _| required from surface resistance _R25A of the conductive coating film before wiping, and surface resistance _R25D of the conductive coating film after wiping. The film strength can be evaluated by the wear surface resistance maintenance rate. Specifically, the higher the wear surface resistance maintenance rate, the higher the film strength.
Wear surface resistance maintenance rate (%) = 100 × R _25D / R _25A

(Example 2)
Conductivity was the same as in Example 1, except that 3.03 g (6 molar equivalents relative to polystyrene sulfonic acid) of N-methylolacrylamide was added to the complex solution 1 instead of 3.48 g of 2-hydroxyethylacrylamide. A functional polymer solution was obtained.
And the electroconductive coating film was formed like Example 1, and electroconductivity, thermal stability, and transparency were evaluated. The results are shown in Table 1.

(Example 3)
In 100 ml of the complex solution 2, 4.95 g (10 molar equivalents relative to polystyrene sulfonic acid) of N, N-dimethylacrylamide and 0.104 g (3% by mass relative to N, N-dimethylacrylamide) of 4 Conductive polymer solution was obtained in the same manner as in Example 1 except that 4,4′-dimethoxybenzophenone was added and dispersed uniformly to obtain a conductive polymer solution.
And the electroconductive coating film was formed like Example 1, and electroconductivity, thermal stability, and transparency were evaluated. The results are shown in Table 1.

(Comparative Example 1)
The composite solution 1 was applied onto a polyethylene terephthalate film whose surface was hydrophilized using a # 12 bar coat. Thereafter, the film was dried in an oven at 100 ° C. to form a conductive coating film.
And the electroconductive coating film was formed like Example 1, and electroconductivity, thermal stability, and transparency were evaluated. The results are shown in Table 1.

(Comparative Example 2)
The composite solution 2 was applied onto a polyethylene terephthalate film whose surface was hydrophilized using a # 12 bar coat. Thereafter, the film was dried in an oven at 100 ° C. to form a conductive coating film.
And the electroconductive coating film was formed like Example 1, and electroconductivity, thermal stability, and transparency were evaluated. The results are shown in Table 1.

The conductive coating film formed by applying the conductive polymer solutions of Examples 1 to 3 containing the (meth) acrylamide compound and polymerizing the (meth) acrylamide compound has a low surface resistance and high conductivity. It was. Moreover, the high temperature surface resistance maintenance factor and the high humidity surface resistance maintenance factor were high, and it was excellent in thermal stability. Further, the total light transmittance was high, the haze was low, the transparency was excellent, the wear surface resistance maintenance rate was high, and the film strength was also high.
On the other hand, the conductive coating film formed by applying the conductive polymer solutions of Comparative Examples 1 and 2 not containing the (meth) acrylamide compound had a high surface resistance value and a low conductivity. Moreover, the high temperature surface resistance maintenance factor and the high humidity surface resistance maintenance factor were low, and it was inferior to thermal stability. Furthermore, the total light transmittance was low, the haze was high, the transparency was inferior, the wear surface resistance maintenance rate was high, and the film strength was low.

Claims (1)

A conductive coating film formed by applying a conductive polymer solution,
The surface resistance is 5000Ω or less,
The conductive polymer solution contains a π-conjugated conductive polymer, a polyanion, a (meth) acrylamide compound having one or more acrylamide groups and / or methacrylamide groups, and a solvent, One of polystyrene sulfonic acid, polyisoprene sulfonic acid, polyacrylic acid ethyl sulfonic acid, polyacrylic acid butyl sulfonic acid,
Content of the said (meth) acrylamide compound is 2-50 molar equivalent with respect to the said polyanion, The electroconductive coating film characterized by the above-mentioned.