JP5388162B2 - Method for producing corrosion-resistant conductive coating material - Google Patents

Description

  The present invention relates to a corrosion-resistant conductive coating material in which a conductive polymer layer that functions as an anticorrosion layer and a conductive layer is formed on copper or an alloy thereof having a very low electric resistance, and a method for producing the same. The present invention relates to a corrosion-resistant conductive coating material that exhibits excellent corrosion resistance and conductivity over a long period of time in an environment in which a metal is easily corroded, such as a halide solution, and a method for producing the same.

  Copper has been widely used as a wiring material or a current collecting material because of its very low electrical resistance compared to other metals. However, since it tends to corrode, it is generally used in a corrosive environment, for example, after being subjected to anticorrosion processing such as a wire cord coated with polyvinyl. Currently, as the main anticorrosion methods for metal substrates such as copper, a method of coating the surface with an organic material or an inorganic material, a method of adding a corrosion inhibitor such as benzotriazole to the bath liquid in an environment where the metal is easily corroded, Examples include an electrochemical protection method that electrochemically suppresses the corrosion current.

  By the way, in the case of applications such as wiring materials and current collecting materials, not only anticorrosion properties but also electrical conductivity are required. Specific examples include power supply rolls used in continuous plating apparatuses for thin metal plates and flexible printed boards, and separators for polymer electrolyte fuel cells that are expected as compact power sources. Conventional materials suitable for these applications include noble metal coating materials by plating or materials coated with a conductive paint.

  However, since noble metal materials are very expensive, thick plating is difficult. When thin plating is performed in order to reduce costs, there is a problem that local batteries are formed due to plating defects such as pinholes and corrosion progresses, and the reliability is also poor. In addition, the noble metal plating bath contains harmful cyanide and the like, and has a problem of high environmental load. Furthermore, it is difficult to uniformly apply a conductive paint to a substrate having many irregularities such as a metal separator and having a complicated shape.

  Various methods have been proposed for these problems. In Patent Document 1, a pinhole is formed by providing two Ni plating layers having different electrode potentials and forming Au plating as the uppermost layer so that the upper layer becomes a more basic Ni layer on the metal substrate. A method of preventing pitting corrosion due to the above and improving the life of the metal substrate is disclosed. Patent Document 2 discloses a technique for uniformly forming a conductive paint by electrodeposition coating.

  Patent Document 1 has two Ni layers and a gold plating layer on a base metal, and a local battery is formed by a pin hole of the gold plating layer and a Ni plating layer having a base electrode potential. Although the Ni plating layer is dissolved, this self-sacrifice utilizes a mechanism for protecting the noble Ni plating layer and the metal substrate. Since the Ni plating layer having a low electrode potential continues to be corroded, the effect disappears with the disappearance of the Ni plating layer, and there is a problem in durability. Patent Document 2 uses an electrodeposition coating composition containing conductive powder as an essential component for coating film formation, and tungsten carbide powder or the like is used as the conductive powder. There is a problem that it is very expensive. Moreover, since an electrodeposition coating composition contains many insulating resin components, it is difficult to achieve high electrical conductivity.

  In order to overcome these problems, there is a method in which a metal coating is coated with a conductive polymer by electrolytic polymerization as a method capable of forming a uniform coating film at a low cost, having both anticorrosion and conductivity. According to Patent Document 3, the surface of the metal substrate is treated by a specific method, and then electropolymerized in an electrolytic solution containing a monomer that is a raw material for the conductive polymer and a carboxylic acid anion. A uniform first conductive polymer layer is formed, and a dense second conductive polymer layer is formed on the first layer by using a specific compound as a dopant compound. A method for providing a corrosion-resistant conductive coating material having excellent properties and conductivity is disclosed.

  However, in the method of Patent Document 3, the first step of treating the metal substrate surface by the specific method, the second step of forming the first conductive polymer layer, and the third step of forming the second conductive polymer layer. A total of three processes were required, and there was a problem inferior in productivity. Furthermore, although the electrical conductivity is higher than that of Patent Document 2, the conductive polymer layer doped with a carboxylate anion inferior in conductivity formed in the oxide layer formed in the first step and in the second step is a resistance component. Therefore, there is a problem that the conductivity is still low as compared with the noble metal plating method.

  Furthermore, when a conductive polymer film is formed on a copper or its alloy substrate by electrolytic polymerization, since the dissolution reaction potential of copper is very low compared to the electrolytic polymerization potential, a general electrolytic polymerization solution is used. In the conventional method in which electrolytic polymerization film formation is performed using a copper substrate as an anode, the dissolution reaction of the copper substrate occurs preferentially, so that the formation of the conductive polymer film is difficult, and the copper polymer or its alloy adheres closely. There remains room for improvement with respect to a method for forming a conductive polymer layer having excellent properties, conductivity and corrosion resistance.

JP 2001-234361 A JP 2004-031166 A JP 2007-250466 A

  It is an object of the present invention to provide a conductive polymer coating material in which a conductive polymer layer is coated on inexpensive copper, even if it is used in an environment where copper is easily corroded, such as in an acidic atmosphere or a halide solution, It is an object to provide a conductive polymer coating material that can suppress dissolution and generation of an insulating film without impairing electrical conductivity and that can withstand long-term use, and a method for manufacturing the same. In addition, it provides a coating method that can be suitably used in obtaining such a coating material having excellent anticorrosion and electrical conductivity, and can be coated with a uniform conductive polymer with excellent adhesion to a copper substrate. It is to be.

  As a result of diligent research on a method for coating a conductive polymer on a substrate made of copper or an alloy thereof, the present inventors have found that when forming a conductive polymer by an electrolytic polymerization method, a plurality of electrolytic polymerization solutions are used. By containing a dopant and appropriately selecting the dopant concentration ratio, it is possible to form a highly conductive polymer film with high adhesion using an electrolytic polymerization method without any special substrate treatment. I found it. Further, the conductive polymer coating material obtained by such a method has been found to have excellent conductivity and long-term corrosion resistance without impairing the good electrical conductivity characteristics of the copper substrate, and completes the present invention. It came to.

That is, the present invention is as shown in (1) below.

( 1 ): Containing a conductive polymer monomer, a carboxylic acid anion, and a sulfonic acid anion, and the carboxylic acid anion was prepared at a concentration ratio (molar ratio) of 0.15 to 0.75 with respect to the sulfonic acid anion. A method for producing a corrosion-resistant conductive coating material, wherein an electroconductive polymer layer is formed on a substrate made of copper or an alloy thereof by electrolytic polymerization using an electrolytic solution.

  It contains a conductive polymer monomer, a carboxylic acid anion and a sulfonic acid anion, and is higher than the copper substrate by electrolytic polymerization in an electrolytic solution in which the carboxylic acid anion concentration is adjusted to the specific ratio. It becomes possible to easily form a dense conductive polymer layer that can express adhesiveness. Furthermore, by using the sulfonate anion as the specific compound, a denser conductive polymer layer can be formed, and the conductive polymer is highly conductive and can be used in an environment such as a corrosive liquid. It works effectively as a barrier film that protects. In addition, by using a compound that exhibits redox activity that is electrochemically reversible as the sulfonate anion, the electrode potential of the coating material can be controlled in accordance with the environment, and the metal anticorrosion effect is dramatically improved. To do. In addition, a coating material having both conductivity and corrosion resistance can be formed without using an expensive noble metal.

  The conductive polymer coating material of the present invention will be described. Examples of the substrate include copper, alloys thereof, zinc, tin, aluminum, and alloys thereof, and copper and alloys thereof are preferably used from the viewpoint of productivity and electrical conductivity. Metal bases such as copper are inexpensive and have excellent electrical conductivity. However, when a conductive polymer is formed on a copper base by electrolytic polymerization, the dissolution reaction potential of copper is very low compared to the electrolytic polymerization potential. . Therefore, in the conventional method of performing electrolytic polymerization film formation using a general electrolytic polymerization solution and using a copper substrate as an anode, the dissolution reaction of the copper substrate occurs preferentially. Have difficulty. Therefore, it is necessary to create an environment in which the conductive polymer is deposited even on the copper substrate.

  As an environment in which the conductive polymer is deposited on the copper substrate, a surface treatment method in which the corrosion resistance is higher than that of the copper substrate while maintaining electrical conductivity may be used. This method includes an oxide film treatment, which is effective when corrosion resistance is particularly required. However, this treatment may not be performed when emphasis is placed on conductivity. As a method for forming the oxide film having conductivity, conventionally known methods can be used. For example, there are a heat treatment method, an oxidizing gas exposure method, an alkali solution treatment method, a sputtering method, etc. A heat treatment method that can easily control the film thickness is suitable.

  Next, a method for forming a dense conductive polymer layer having excellent corrosion resistance by electrolytic polymerization will be described with reference to the drawings. First, a compound containing a carboxylic acid anion and a sulfonic acid anion as a supporting electrolyte and a conductive polymer monomer are dissolved in a solvent to prepare an electrolytic polymerization solution, and the copper base is used as an electrode (anode), and the cathode is made of carbon or stainless steel. In the initial stage of electrolytic polymerization, three reactions occur on the copper substrate.

In general, when a conductive polymer film is formed by electrolytic polymerization, hydrochloric acid, sulfuric acid, tetrabutylammonium tetrafluoroborate (TBABF ₄ ), etc. are used as a supporting electrolyte. Since the copper dissolution reaction potential is lower than the potential, the copper dissolution reaction occurs preferentially. Therefore, until now, it has been difficult to form a conductive polymer film directly on a copper substrate. However, the present invention is characterized in that a conductive polymer film having high adhesion is formed by actively utilizing this reaction.

  FIG. 1 is a schematic view showing a mechanism for depositing a conductive polymer on a copper substrate according to the present invention. As shown in the first stage in FIG. 1, as the first reaction, the etching reaction proceeds on the copper surface of the anode by the sulfonate anion released from the supporting electrolyte added for forming the conductive polymer film. To do. By this etching reaction, the copper surface is roughened, and a surface serving as an anchor of the conductive polymer layer is formed.

  In the second reaction, a carboxylate anion present in the electrolytic polymerization solution reacts with copper, whereby copper carboxylate having high corrosion resistance and electrical conductivity is deposited on the surface of the substrate. Since the reaction proceeds almost simultaneously with the copper etching reaction in the first stage, as shown in the second stage in FIG. 1, copper carboxylate is deposited on the surface of the copper substrate.

  In general, the deposition potential of a conductive polymer doped with a carboxylate anion is lower than the deposition potential of a copper salt of carboxylate, which is a salt skin substance. Therefore, as the third reaction shown in the third stage in FIG. The conductive polymer doped with the carboxylic acid anion present in the electrolytic polymerization solution starts to deposit on the carboxylic acid copper. That is, the conductive polymer doped with a carboxylic acid anion starts to precipitate so as to cover the carboxylic acid copper scattered on the surface of the copper substrate.

  Through the third stage or simultaneously with the third stage, it is possible to deposit a conductive polymer doped with a sulfonate anion having high corrosion resistance and high conductivity, which is the fourth reaction shown in the fourth stage in FIG. It becomes. That is, deposition of a conductive polymer doped with a sulfonate anion having a lower deposition potential starts on or in the vicinity of the conductive polymer doped with a carboxylate anion. Actually, the above-described reaction occurs instantaneously, and precipitation occurs in a state in which copper carboxylate, a conductive polymer doped with a carboxylate anion, and a conductive polymer doped with a sulfonate anion are mixed. As a result, on the copper surface, a mixed layer is formed in which a conductive polymer doped with a highly conductive sulfonate anion is dispersed in a conductive polymer doped with copper carboxylate and carboxylic acid, which have poor conductivity. By passing through the conductive polymer, a conductive path is formed in the conductive polymer layer doped with copper carboxylate and carboxylic acid having poor conductivity. As a result, good conductivity between the copper base and the conductive polymer doped with the sulfonate anion can be maintained.

  As an environment where the metal is corroded, there are not only an acidic atmosphere such as an aqueous hydrochloric acid solution or an aqueous sulfuric acid solution but also an oxidizing atmosphere such as an aqueous sodium hypochlorite solution. In such an environment, a dopant having a carboxylic acid group does not function as an anion when the carboxyl group of the dopant is oxidized, so that the electrical conductivity of the conductive polymer may be impaired. Therefore, in an oxidative corrosive environment, the anti-corrosion and oxidation resistance is very high, and the electropolymerization solution is doped with a large amount of sulfonate anions so that a dense conductive polymer layer can be formed. There is a need to pay particular attention to the composition. By the way, the number of sulfonic acid groups in the sulfonic acid anion compound used in the present invention can be monovalent or polyvalent, and is not particularly limited.

  Examples of the conductive polymer monomer formed on the surface of the copper substrate include pyrrole, thiophene, alkylthiophene, alkylenedioxythiophene, aniline, phenylene, acetylene, furan, phenylene vinylene, acene, azulene and derivatives thereof, or 2 Examples of the copolymer include pyrrole, alkylthiophene, alkylenedioxythiophene, aniline and derivatives thereof, which are excellent in corrosion resistance and electrical conductivity.

  In order to obtain a high barrier property for protecting the substrate from high electrical conductivity and corrosive environment, the electrolytic polymerization method or the solution method is suitable for polypyrrole derivatives and aniline derivatives, and electrolysis is used for polyalkylthiophene derivatives and polyalkylenedioxythiophenes. A polymerization method or a chemical polymerization method is preferred. In particular, a conductive polymer film formed by an electrolytic polymerization method has a high electrical conductivity because of a high doping rate, and easily obtains a dense conductive polymer film having a higher orientation than other forming methods. Therefore, it is most suitable as a method for forming a conductive polymer film.

It is preferable that the carboxylate anion used as the dopant has a concentration ratio (molar ratio) of 0.15 to 0.75 with respect to the sulfonate anion present in the electrolytic polymerization solution. This is because, it is less than 0.15, in order to deposit the copper carboxylate is a main etching reaction becomes difficult, deposition of the conductive polymer becomes difficult, a 0.75 greater than the conductive polymer in the precipitated This is because a carboxylate anion is mainly used as an anion to be doped in the metal, and oxidation resistance may be deteriorated.

Regarding the above ratio, when emphasis is placed on conductivity, the carboxylic acid anion may have a concentration ratio (molar ratio) of 0.15 to 0.5 with respect to the sulfonic acid anion present in the electrolytic polymerization solution. More preferably, when emphasizing the anticorrosion property, it is more preferable to set the carboxylate anion to a concentration ratio (molar ratio) of 0.4 to 0.75 with respect to the sulfonate anion present in the electrolytic polymerization solution. The ratio of the sulfonate anion and the carboxylate anion in the electrolytic polymerization solution may be changed as appropriate according to the environment and purpose of use.

Examples of the carboxylate anion include aminoindane carboxylic acid, aminotetralin carboxylic acid, tetrahydroisoquinoline carboxylic acid, tetrahydro-β-carboline carboxylic acid, aurine tricarboxylic acid, acridine carboxylic acid, acetyl piperidine carboxylic acid, acetylenedicarboxylic acid, acetone dicarboxylic acid, Azetidinenedicarboxylic acid, adamantanecarboxylic acid, aminoindanedicarboxylic acid, aminocarbonylcyclopropanecarboxylic acid, aminocyclopropanecarboxylic acid, aminocyclohexanecarboxylic acid, aminocyclopentanecarboxylic acid, aminodihydrophenalenecarboxylic acid, aminodimethylpyridinecarboxylic acid Acid, aminotetralin carboxylic acid, aminotriazole carboxylic acid, aminobicycloheptane carboxylic acid, aminopirine Gin carboxylic acid, aminopyrazole carboxylic acid, aminomethylcyclohexane carboxylic acid, anthracene carboxylic acid, anthraquinone carboxylic acid, isoquinoline carboxylic acid, imidazole dicarboxylic acid, indole carboxylic acid, indoline carboxylic acid, uracil carboxylic acid, ethyl thiazolidine carboxylic acid, ethyl biphenyl Carboxylic acid, oxotetrahydrofuran carboxylic acid, oxopiperidine carboxylic acid, oxobenzopyran carboxylic acid, carboxylic quinoxaline carboxylic acid, quinoline carboxylic acid, chloroindole carboxylic acid, chloroethylfluorooxohydroquinoline carboxylic acid, chloroethylenedioxybicycloheptane carboxylic acid , Chlorooxo-bicycloheptanecarboxylic acid, chlorocyclopropylfluorooxohydroquino Phosphorus carboxylic acid, chlorothiophene carboxylic acid, chlorophenyl cyclobutane carboxylic acid, chlorophenyl cyclopropane carboxylic acid, chlorophenyl cyclohexane carboxylic acid, chlorophenyl cyclopentane carboxylic acid, chlorofluorocyclopropyl dihydrooxoquinoline carboxylic acid, chlorofluorophenyl cyclohexane carboxylic acid, chlorofluoro Phenylcyclohexanecarboxylic acid, chlorofluorophenylcyclopentanecarboxylic acid, chlorofluorophenylcyclopentanecarboxylic acid, chlorobenzoylcyclohexanecarboxylic acid, chloromethylpyridinecarboxylic acid, ethyl chloromethylfurancarboxylate, salicylic acid, cyanocyclopropanecarboxylic acid, cyclobutanecarboxylic acid Acid, cyclobutane dicarboxylic acid, cyclo Lopancarboxylic acid, cyclohexanecarboxylic acid, cyclohexanedicarboxylic acid, cyclohexenecarboxylic acid, cyclopentanecarboxylic acid, cyclopentanetetracarboxylic acid, dichlorophenylcyclopropanecarboxylic acid, dichlorofluoropyridinecarboxylic acid, dihydroxyanthraquinonecarboxylic acid, dihydroxypyrimidinecarboxylic acid, dihydrodimethyl Oxopyrancarboxylic acid, difluorodihydromethyloxopyridobenzoxazinecarboxylic acid, hydroxybenzenecarboxylic acid, hydroxynaphthoic acid, dimethylaminoazobenzenecarboxylic acid, dimethyldiphenyldicarboxylic acid, thiazolidinecarboxylic acid, thiophenecarbonylcyclohexanecarboxylic acid, thiophenecarbonylcyclohexanecarboxylic acid Acid, thiophenecarbo Acid, tetrahydroacridinecarboxylic acid, tetrahydroisoquinolinecarboxylic acid, tetrahydrooxofurancarboxylic acid, tetrahydrofurantetracarboxylic acid, tetramethylimidazolineoxylcarboxylic acid, tetramethylpiperidineoxylaminocarboxylic acid, tetramethylpyrrolineoxylcarboxylic acid, decanedicarboxylic acid, tosyl Pyrrole carboxylic acid, trihydroxycyclohexene carboxylic acid, trimethylthiazoline carboxylic acid, cyclopentane carboxylic acid, dodecanedicarboxylic acid, naphthalenedicarboxylic acid, naphthoquinone carboxylic acid, nitroindole carboxylic acid, benzenetetracarboxylic acid, benzophenonetetracarboxylic acid, perylenetetracarboxylic acid Acid, noradamantanecarboxylic acid, rubornene dicarboxylic acid, hydroxy Indole carboxylic acid, hydroxyquinoquinoxaline carboxylic acid, hydroxy quinoline carboxylic acid, hydroxy cyclopropane carboxylic acid, hydroxy tetrahydroisoquinoline carboxylic acid, hydroxy trifluoromethyl quinoline carboxylic acid, hydroxy (2-hydroxy-4-sulfo-1-naphthylazo) naphthalene Carboxylic acid, hydroxybiphenylcarboxylic acid, hydroxypyridinecarboxylic acid, hydroxypyrrolidinecarboxylic acid, hydroxymethylquinolinecarboxylic acid, hydroxymethylpyridinecarboxylic acid, bicyclooctenetetracarboxylic acid, biphenylcarboxylic acid, bibenzylcarboxylic acid, piperazinecarboxylic acid, piperidine Carboxylic acid, pyrazine carboxylic acid, pyrazine dicarboxylic acid, pyrazole dicarboxylic acid, pyridine cal Acid, pyridinedicarboxylic acid, pyrrolidinecarboxylic acid, pyrrolidinecarboxylic acid, pyrrolidonecarboxylic acid, phenylcyclopropanecarboxylic acid, phenylcyclohexanecarboxylic acid, phenylcyclopentanecarboxylic acid, phenylthiazolidinecarboxylic acid, phenylpyrrolidinecarboxylic acid, ferrocenedicarboxylic acid, Furancarboxylic acid, fluorenonecarboxylic acid, fluoroindolecarboxylic acid, (fluorophenyl) cyclohexanecarboxylic acid, (fluorophenyl) cyclopentanecarboxylic acid, (fluorobenzoyl) cyclohexanecarboxylic acid, butylcyclohexanecarboxylic acid, (tert-butyldimethylsilyl) Azetidinone carboxylic acid, butylpyridine carboxylic acid, (tert-butoxycarbonylamino) cyclohexane Rubonic acid, (tert-butoxycarbonylamino) cyclopentanecarboxylic acid, (tert-butoxycarbonylamino) tetrahydronaphthalene-2-carboxylic acid, bromoethylenedioxybicycloheptanecarboxylic acid, (bromobenzoyl) cyclohexanecarboxylic acid, propylcyclohexanecarboxylic acid Acid, propylbiphenylcarboxylic acid, (benzyloxycarbonylamino) cyclohexanecarboxylic acid, (benzyloxycarbonylamino) bicycloheptenecarboxylic acid, (benzyloxycarbonyl) tetrahydroisoquinolinecarboxylic acid, benzenetetracarboxylic acid, benzenetricarboxylic acid, benzoylcyclohexane Carboxylic acid, benzoylbicycloheptanecarboxylic acid, benzoylphenylcyclohexanecarboxylic acid , Thiophenecarboxylic acid, benzotellophenecarboxylic acid, benzophenonecarboxylic acid, benzofurancarboxylic acid, pentylcyclohexanecarboxylic acid, cyclohexanedicarboxylic acid, dihydrodithiindicarboxylic acid, norbornene dicarboxylic acid, bicyclooctene dicarboxylic acid, pyridinedicarboxylic acid, phenylcyclohexane Dicarboxylic acid, hexachloronorbornene dicarboxylic acid, benzenetricarboxylic acid, methylnorbornene dicarboxylic acid, methylcyclopropanecarboxylic acid, methylcyclohexanecarboxylic acid, methylthiazolidinecarboxylic acid, methylthiophenecarboxylic acid, methyltetrahydroisoquinolinecarboxylic acid, methylpyrazinecarboxylic acid, methyl Pyrrole carboxylic acid, methyl pyrrolidine carboxylic acid, methyl pyrrolidine Rubonic acid, (methylphenyl) cyclopropanecarboxylic acid, (methylphenyl) cyclohexanecarboxylic acid, methylbenzimidazolecarboxylic acid, methylbenzenesulfonic acid phenylpiperidinecarboxylic acid, (p-methylbenzoyl) cyclohexanecarboxylic acid, (p-methylbenzoyl) ) Cyclohexanecarboxylic acid, methylenecyclopropanedicarboxylic acid, methylenebis (hydroxy-naphthalenecarboxylic acid) methoxyindolecarboxylic acid, (methoxyphenyl) cyclopropanecarboxylic acid, (methoxyphenyl) cyclohexanecarboxylic acid, (methoxyphenyl) cyclopentanecarboxylic acid, Adamantaneacetic acid, anilinoacetic acid, aminoacetic acid, aminophenylacetic acid, isodehydroacetic acid, iminodiacetic acid, indoleacetic acid, ethylacetate Acid, ethylenediaminetetraacetic acid, ethoxyacetic acid, oxalacetic acid, oxydiacetic acid, cresyl violet acetic acid, chlormadinone acetic acid, chlorodifluoroacetic acid, chlorophenylacetic acid, guanidine acetic acid, glucose pentaacetic acid, iminodiacetic acid, tetramethyl acetate, cyanoacetic acid, cyclohexane Diacetic acid, cyclohexylacetic acid, cyclohexylphenylacetic acid, cyclopentylacetic acid, diphenylacetic acid, diethylphosphonoacetic acid, diethylenetriaminepentaacetic acid, dichloroindoleacetic acid, dichloroacetic acid, dichlorophenylacetic acid, dihydroxyphenylacetic acid, difluorophenylacetic acid, butylmethylphenyldiazoacetic acid, dibromo Acetic acid, styryl acetic acid, thiol acetic acid, sulfoacetic acid, thioacetic acid, thiophene acetic acid, dehydroacetic acid, triethylenetetramine hexaacetic acid, trichloro Acetic acid, tribromoacetic acid, trimethylacetic acid, trimethoxyphenylacetic acid, tolylacetic acid, naphthaleneacetic acid, naphthylacetic acid, naphthoxyacetic acid, nitrilotriacetic acid, nitrophenylacetic acid, nitrophenoxyacetic acid, nonylphenoxyacetic acid, hydantoinacetic acid, hydrazineacetic acid, hydroxyacetic acid , Hydroxyphenylacetic acid, hydroxyphenoxyacetic acid, hydroquinoneacetic acid, vinylacetic acid, biphenylacetic acid, phenylcyclopentaneacetic acid, phenylenediacetic acid, phenylenediacetic acid, phenoxyacetic acid, fluorophenylacetic acid, butylacetic acid, butoxyacetic acid, bromoacetic acid, bromophenylacetic acid , Pentafluorophenylacetic acid, formylphenoxyacetic acid, chloroacetic anhydride, acetic anhydride, trifluoroacetic anhydride, trimethylacetic anhydride, iodoacetic anhydride, methylaminoacetic acid, Louisinodiacetic acid, methylsulfonylphenylacetic acid, methylphenylacetic acid, methoxyindoleacetic acid, methoxyacetic acid, methoxyphenylacetic acid, mercaptoacetic acid, monochloroacetic acid, iodoacetic acid, oxalic acid, formic acid, tartaric acid, citric acid and alkali metal salts thereof and their derivatives Anionic components such as ammonium salts of
More preferably, benzenecarboxylic acid, hydroxybenzenecarboxylic acid, naphthoquinonecarboxylic acid, anthracenecarboxylic acid, anthraquinonecarboxylic acid, ethylenediaminetetraacetic acid, trifluoroacetic acid, naphthalenedicarboxylic acid, butoxyacetic acid, vinylacetic acid, oxalic acid, ferrocenedicarboxylic acid, oxalic acid And anionic components such as tartaric acid, citric acid and alkali metal salts of derivatives thereof and ammonium salts thereof.

  The molecular weight of the sulfonate anion, which is the other dopant, is preferably 240 or more. If the molecular weight is less than 240, the molecular weight is small, that is, the molecule is small, so that the dedoping action occurs in the solution. This is because the electrical conductivity of the conductive polymer may be lost. Specific examples of the dopant compound having one or more sulfonic acid groups and a molecular weight of 240 or more include anionic components such as sodium ferrocenesulfonate and sodium ligninsulfonate. A conductive polymer film containing such a dopant is suitable because it has a large barrier effect for blocking the corrosive environment from the substrate.

  Furthermore, as the molecular structure of the sulfonate anion, the sulfonate anion having a benzene condensed ring and / or two or more aromatic rings can be intricately intertwined with the polymer chain of the conductive polymer, resulting in a more precise structure. It is possible to produce and increase the barrier effect more preferably. In addition, the sulfonate anion is suitable because it has an effect of being difficult to dedope by being intricately entangled with the conductive polymer chain.

  Examples of the sulfonic acid anion include anthracene sulfonic acid, anthracene sulfonic acid, diphenylamine sulfonic acid, alkali metal salts of diphenylamine sulfonic acid and ammonium salts thereof, acid black 1, acid blue 1, acid blue 3, acid Blue 9, Acid Blue 20, Acid Blue 74, Acid Blue 83, Acid Blue 92, Acid Blue 119, Acid Blue 147, Acid A, Acid Brilliant Green J, Acid Brown M, Acid Captor H, Acid Captor 9M, Acid Cyanine 6B , Acid First Yellow G, Acid Faxin, Acid Green 1, Acid Green 3, Acid Green 5, Acid Green 9, Acid G 16, Acid Green 50, Acid Green B, Acid Green GG, Acid Light Yellow 2G, Acid Orange 5, Acid Orange 6, Acid Orange 7, Acid Orange 17, Acid Orange 20, Acid Red, Acid Red 1, Acid Red 2, Acid Red 9, Acid Red 13, Acid Red 18, Acid Red 18, Acid Red 26, Acid Red 27, Acid Red 29, Acid Red 52, Acid Red 60, Acid Red 87, Acid Red 88, Acid Red 91, Acid Red 92, Acid Red 94, Acid Red 112, Acid Red 265, Acid Bio Red 6B, Acid Bio Red 34, Acid Bio Red 43, Acid Bio Red 49, Acid Yellow 3, Acid Yellow 23, Acid Red 36, Acid Yellow 73, Acid Yellow 186, Sulfonazo III, Moldant 29, Sun Chromaine Blue Black R, Sun Chromaine Blue Black MB, Sun Chromaine Blue Black MD, Sunset And anionic components such as Yellow FCF, Alpha Mine Red R, Alpha Mine Red R base, Arsenazo I, Arsenazo III and their derivatives.

  Further, as the sulfonate anion, those having at least one carboxyl group and at least one sulfonate group in the molecule can be used. Examples of such anions include sulfosalicylic acid and derivatives thereof.

  In addition, among the sulfonate anions having the above-described structure, a conductive polymer film containing a sulfonate anion having at least one sulfonate group and exhibiting electrochemically reversible oxidation-reduction activity is also provided. In addition to having the function of providing a barrier property between the corrosive liquid and the substrate, when exposed to a corrosive environment, the sulfonate anion performs a redox reaction in accordance with the environment. This is preferable because the anticorrosion effect of the substrate becomes particularly remarkable in order to electrochemically control the electrode potential of the conductive polymer coating material.

  The electrochemically reversible redox activity described above is a compound capable of exhibiting an electrochemically reversible redox reaction, that is, oxidized at the anode and reduced at the cathode to return to the original state. Refers to a compound. For example, the quinone structure site contained in naphthoquinonesulfonic acid is oxidized at the anode to become a hydroxy group, but the hydroxy group site is reduced at the cathode to return to the quinone structure. This reaction can be confirmed by the cyclic voltammetry method, and the reaction peak during the oxidation reaction and the reaction peak during the reduction reaction appear at substantially the same potential.

  Examples of the sulfonic acid anion containing at least one sulfonic acid group having electrochemically reversible redox activity include ferrocene sulfonic acid, hydroquinone sulfonic acid, anthoquinone sulfonic acid, naphthoquinone sulfonic acid, and azaxanthone sulfonic acid. , Anionic components such as benzanthraquinone sulfonic acid, benzanthrone sulfonic acid, phenylazobenzene sulfonic acid, benzoquinone sulfonic acid, dye anthraquinone irin R, anthraquinone bio red RN-3RN, but with oxidation resistance and dedoping action From the viewpoint of inhibition, ferrocene sulfonic acid, anthraquinone sulfonic acid, naphthoquinone sulfonic acid, azaxanthone sulfonic acid, benzanthraquinone sulfonic acid, benzanthrone sulfonic acid, pheny Azobenzene sulfonic acid, dye and is anthraquinone Irene R, and it is more preferable to use the anionic component of the anthraquinone violet RN-3RN.

  Among them, a sulfonate anion having a sulfonic acid group containing a quinone structure and one or more aromatic rings has high electrochemical activity and a high redox potential. Therefore, the redox potential of the conductive polymer film containing the sulfonate anion is shifted to the most noble and the effect of protecting the copper substrate can be maximized. Therefore, the sulfonate anion is used. Most preferred. Specific examples of the dopant having such a sulfonate anion include anthraquinone sulfonic acid and naphthoquinone sulfonic acid.

  The above-mentioned supporting electrolyte containing each sulfonate anion may be contained alone in the electrolytic polymerization solution, or may be prepared so as to exist in plural. Furthermore, the total content of the dopant contained in the conductive polymer film is preferably 0.001 to 1 mol with respect to 1 mol of the monomer.

  In addition, the conductive polymer film is damaged when forming a substrate having a complicated shape by performing a conductive polymer formation process after bending, such as pressing, cutting, etching, etc., on the substrate in advance. Therefore, the effect of the conductive polymer film can be reliably obtained. That is, regarding the formation of the conductive polymer film, if the electropolymerization is performed using the processed substrate as an electrode as described above, the conductive polymer film is uniformly formed even if the substrate surface is uneven by processing. And stable performance can be obtained.

  The thickness of the conductive polymer to be formed is suitably from 0.001 μm to 100 μm, but from an economic point of view, 0.001 μm to 50 μm is more preferable, and 0.01 μm to 35 μm is most preferable.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited at all by the Example.

Example 2
A phosphorous deoxidized copper plate was used as the substrate. The phosphorous deoxidized copper plate was a rolled material having a size of 20 × 30 mm and a thickness of 0.2 mm. This substrate was degreased by immersing it in a solution adjusted to 10 g / L of sodium hydroxide, 40 g / L of sodium carbonate, 10 g / L of sodium silicate, and 0.1 g / L of dodecylbenzenesulfonic acid, The substrate surface treatment was performed by immersing in a copper surface activation solution adjusted to 1.0 mol / L of hydrochloric acid for 1 minute, and the resulting solution was supplied into an electrolytic polymerization solution.

Next, a conductive polymer film containing a carboxylate anion and a sulfonate anion as dopants was formed by electrolytic polymerization. Using an electrolytic solution containing pure water as a solvent, 0.5 mol / L of pyrrole as a monomer, 0.05 mol / L of sodium trifluoroacetate as a supporting electrolyte, and 0.25 mol / L of tetraethylammonium-2-anthracenesulfonic acid. Then, the base was the anode, the SUS304 was the cathode, the electropolymerization time was 15 minutes, the current density was 10 mA / cm ² , electropolymerization was performed to form a polypyrrole film, and a total of 10 corrosion-resistant conductive coating materials were produced.

Example 3
A brass plate (copper 75% -zinc 25%) was used as the substrate. The brass plate was a rolled material having a size of 20 × 30 mm and a thickness of 0.2 mm. The substrate was degreased with acetone, and then immersed in a copper surface activation solution adjusted to 2.0 mol / L of sulfuric acid for 1 minute to subject the substrate to a surface treatment, which was used in an electrolytic polymerization solution.

Next, a conductive polymer film containing a carboxylate anion and a sulfonate anion as dopants was formed by electrolytic polymerization. Propylene carbonate as solvent, ethylenedioxythiophene 0.3 mol / L as monomer, tetraethylammonium-6-hydroxy-2-naphthoic acid 0.05 mol / L, tetraethylammonium acid black 0.20 mol / L as supporting electrolyte Electrolytic polymerization is performed using an electrolytic solution containing the substrate as an anode, SUS304 as a cathode, an electropolymerization time of 30 minutes, and a current density of 5 mA / cm ² to form a polyethylene dioxythiophene film, and a corrosion-resistant conductive coating material. A total of 10 sheets were produced.

Example 4
A phosphorous deoxidized copper plate was used as the substrate. The phosphorous deoxidized copper plate was a rolled material having a size of 20 × 30 mm and a thickness of 0.2 mm. This substrate was degreased by immersing it in a solution adjusted to 10 g / L of sodium hydroxide, 40 g / L of sodium carbonate, 10 g / L of sodium silicate, and 0.1 g / L of dodecylbenzenesulfonic acid, The substrate surface treatment was performed by immersing in a copper surface activation solution adjusted to 1.0 mol / L of hydrochloric acid for 1 minute, and the resulting solution was supplied into an electrolytic polymerization solution.

  Next, a conductive polymer film containing a carboxylate anion and a sulfonate anion as dopants was formed by electrolytic polymerization. The solvent is pure water, the monomer is aniline 0.5 mol / L, the supporting electrolyte is tetraethylammonium-3,5-dihydroxy-2-naphthoic acid 0.10 mol / L, tetraethylammonium-1,5-naphthoquinone-4- Using an electrolyte containing 0.20 mol / L of sulfonic acid, the base is an anode, Au is a cathode, silver / silver chloride (saturated KCl) is a reference electrode, the electrode electropolymerization time is 1 hour, and the electrolysis voltage is 0.9 V ( (vs silver / silver chloride reference electrode) was subjected to constant potential electropolymerization to form a polyaniline film, to form a polyaniline film, and a total of 10 corrosion-resistant conductive coating materials were produced.

Example 5
A white copper plate (copper 90% -nickel 10%) was used as the substrate. The copper silicate plate was a rolled material having a size of 20 × 30 mm and a thickness of 0.2 mm. After degreasing the substrate with acetone, the substrate surface treatment was performed by immersing in a copper surface activation solution adjusted to 0.5 mol / L hydrofluoric acid and 0.1 mol / L nitric acid for 3 minutes. It was used for.

Next, a conductive polymer film containing a carboxylate anion and a sulfonate anion as dopants was formed by electrolytic polymerization. Electrolyte containing pure water as solvent, 0.3 mol / L thiophene as monomer, 0.04 mol / L sodium 2,5-dihydroxybenzoate as support electrolyte, and 0.12 mol / L tetraethylammonium anthraquinone-2-sulfonate Using the solution, the substrate is the anode, the SUS304 is the cathode, the electropolymerization time is 20 minutes, the current density is 7.5 mA / cm ² , the polythiophene film is formed, and a total of 10 corrosion-resistant conductive coating materials are formed. Produced.

Example 6
A phosphorous deoxidized copper plate was used as the metal substrate. The phosphorous deoxidized copper plate was a rolled material having a size of 20 × 30 mm and a thickness of 0.2 mm. This substrate was degreased by immersing it in a solution adjusted to 10 g / L of sodium hydroxide, 40 g / L of sodium carbonate, 10 g / L of sodium silicate, and 0.1 g / L of dodecylbenzenesulfonic acid, The substrate surface treatment was performed by immersing in a copper surface activation solution adjusted to 1.0 mol / L of hydrochloric acid for 1 minute, and the resulting solution was supplied into an electrolytic polymerization solution.

Next, a conductive polymer film containing a carboxylate anion and a sulfonate anion as dopants was formed by electrolytic polymerization. Electrolysis containing pure water as solvent, pyrrole 0.3 mol / L as monomer, ammonium anthraquinone-2-carboxylate 0.03 mol / L, anthraquinone-2,6-disulfonate ammonium 0.07 mol / L as supporting electrolyte Using the solution, the substrate was the anode, the SUS304 was the cathode, the electropolymerization time was 15 minutes, the current density was 10 mA / cm ² , and the polypyrrole film was formed to produce a total of 10 corrosion-resistant conductive coating materials. .

Reference example 1
In Example 3, the electrolytic solution was propylene carbonate, the monomer was ethylenedioxythiophene 0.3 mol / L, the supporting electrolyte was tetraethylammonium-6-hydroxy-2-naphthoic acid 0.09 mol / L, tetraethyl Except having adjusted so that it might contain 0.01 mol / L of ammonium acid black, it implemented similarly and produced ten sheets of corrosion-resistant electrically conductive coating materials.

Comparative Example 2
In Example 2, it was carried out in the same manner except that tetraethylammonium-2-anthracenesulfonic acid was not added as a supporting electrolyte and an electrolytic solution containing only 0.3 mol / L of sodium trifluoroacetate was used. 10 sheets were produced.

Comparative Example 3
According to the method described in Patent Document 3, a corrosion-resistant conductive coating material was produced. First, a brass plate (copper 75% -zinc 25%) was used as a metal substrate. The brass plate was a rolled material having a size of 20 × 30 mm and a thickness of 0.2 mm. The substrate was degreased with an acetone solvent and then immersed in a NaOH 40% aqueous solution (90 ° C.) for 90 minutes to form an oxide film on the substrate surface.

Next, a conductive polymer film containing a carboxylic acid anion as a dopant was formed by electrolytic polymerization. The substrate was anoded using an electrolyte containing propylene carbonate as the monomer, ethylenedioxythiophene 0.3 mol / L as the monomer, and tetraethylammonium-6-hydroxy-2-naphthoic acid 0.9 mol / L as the supporting electrolyte. Then, SUS304 was used as the cathode, the electropolymerization time was 15 minutes, and the current density was 5 mA / cm ² , and the electropolymerization was performed to form a polyethylenedioxythiophene film.

Subsequently, a dense conductive polymer film was formed by electrolytic polymerization. Conductivity containing propylene carbonate as solvent, ethylenedioxythiophene as a monomer 0.20 mol / L, electrolyte containing tetraethylammonium-trifluoromethanesulfonic acid 0.9 mol / L as a supporting electrolyte, and carboxylate anion as a dopant The base on which the conductive polymer film is formed is the anode, Pt is the cathode, the electropolymerization time is 15 minutes, the current density is 5 mA / cm ² , and the polyethylenedioxythiophene film is formed, and the corrosion-resistant conductive coating material is formed. Ten sheets were produced.

Comparative Example 4
In Example 4, ten pieces of corrosion-resistant conductive coating materials were produced in the same manner except that tetraethylammonium hexafluorophosphoric acid was used instead of tetraethylammonium-1,5-naphthoquinone-4-sulfonic acid as the supporting electrolyte. did.

Comparative Example 5
According to the method described in Patent Document 3, a corrosion-resistant conductive coating material was produced. First, a white copper plate (copper 90% -nickel 10%) was used as a metal substrate. The white copper plate was a rolled material having a size of 20 × 30 mm and a thickness of 0.2 mm. The substrate was degreased with an acetone solvent and then immersed in a NaOH 40% aqueous solution (90 ° C.) for 90 minutes to form an oxide film on the substrate surface.

Next, a conductive polymer film containing a carboxylic acid anion as a dopant was formed by electrolytic polymerization. A solvent is acetonitrile, an electrolyte containing 0.3 mol / L of thiophene as a monomer, and 0.15 mol / L of tetraethylammonium-2,5-dihydroxybenzoic acid as a supporting electrolyte, a substrate as an anode, SUS304 as a cathode, Electropolymerization was carried out for 30 minutes at a current density of ² mA / cm ² to form a polythiophene film.

Subsequently, a dense conductive polymer film was formed by electrolytic polymerization. The solvent is pure water, an electrolysis solution containing 0.20 mol / L of thiophene as a monomer and 0.1 mol / L of anthraquinone-2-sulfonic acid tetraethylammonium as a supporting electrolyte, and a conductive high ion containing a carboxylate anion as a dopant. The substrate on which the molecular film was formed was the anode, Pt was the cathode, the electropolymerization time was 1 hour, the current density was 5 mA / cm ² , the electropolymerization was performed to form the polythiophene film, and 10 corrosion-resistant conductive coating materials were produced.

Comparative Example 6
The same procedure as in Example 6 was carried out except that tetraethylammonium tetrafluoroborate was used instead of ammonium anthraquinone-2-carboxylate as the supporting electrolyte, and ammonium perchlorate was used instead of ammonium anthraquinone-2,6-disulfonate. As a result, a polypyrrole film could not be formed by a copper dissolution reaction.

Corrosion-proof and conductivity evaluation With respect to the corrosion-resistant conductive coating materials of Examples 2 to 6, Reference Example 1 and Comparative Examples 2 to 5 prepared as described above, sulfuric acid was adjusted to 100 g / L and the bath temperature was maintained at 65 ° C. A 90-day immersion test was carried out in a corrosive aqueous solution that was stirred with air. After the test is completed, the ion concentration of the metal substrate contained in the sulfuric acid aqueous solution was measured with a sequential high-frequency plasma emission analyzer, and the results of comparing the anticorrosion properties are shown in Table 1. Table 3 shows the result of comparison between the initial resistance at a load of 10 kg / cm ² and the implementation after the immersion test by the contact resistance measurement method shown in FIG.

Moreover, with respect to the corrosion-resistant conductive coating materials of Examples 2 to 6, Reference Example 1 and Comparative Examples 2 to 5 produced in this way, hydrochloric acid was adjusted to 3.0 mol / L, and the bath temperature was maintained at 30 ° C. and air A 90-day immersion test was carried out in the stirred corrosive aqueous solution. Table 2 shows the results obtained by measuring the ion concentration of the metal substrate contained in the hydrochloric acid aqueous solution with a sequential high-frequency plasma emission spectrometer after the test, and comparing the corrosion resistance. Table 4 shows the result of comparison between the initial resistance at a load of 10 kg / cm ² and after the immersion test by the contact resistance measurement method shown in FIG.

Evaluation of Fuel Cell Separator A polythiophene film was formed on a 0.1 mm thick copper foil having a gas flow path formed by press working by the method described in Example 5 and Comparative Example 5 to obtain a solid polymer fuel A battery separator was produced. A cell was assembled using a solid electrolyte membrane carrying a catalyst on both electrodes, a gas diffusion electrode, and the separator described above, and power generation was performed using high-purity hydrogen gas and air as fuel, and IV characteristics were examined. Subsequently, the results of examining the IV characteristics in the same manner after the continuous power generation test for 1000 hours was shown in FIG.

According to the results in Table 1, each of the corrosion-resistant conductive coating materials of Examples 2 to 6 according to the present invention protected the substrate without any change even after 90 days of the immersion test, and excellent corrosion resistance even in an acidic atmosphere. It was found to have an effect. On the other hand, peeling of the conductive polymer film was confirmed in the materials produced in Comparative Examples 2 and 4 in which the immersion test was similarly performed due to corrosion of the substrate.

According to the results of Table 2, each of the corrosion-resistant conductive coating materials of Examples 2 to 6 according to the present invention protected the substrate without any change even after 90 days of immersion test, and excellent corrosion protection even in an acidic halogen atmosphere. It was found to have sexual effects. On the other hand, peeling of the conductive polymer film was confirmed in the materials produced in Comparative Examples 2 and 4 in which the immersion test was similarly performed due to corrosion of the substrate.

According to the results in Table 3, it is recognized that each of the corrosion-resistant conductive coating materials of Examples 2 to 6 according to the present invention retains good contact resistance even after 90 days of immersion test and has excellent current collecting characteristics. It was. On the other hand, in the coating materials prepared in Comparative Examples 2 and 4 in which the immersion test was conducted in the same manner, the corrosion of the substrate also progressed with time, and after 90 days, the contact resistance became 1000 mΩ · cm ² or more, and the conductive characteristics disappeared. Was. In the materials prepared in Comparative Examples 3 and 5, it was found from the results in Table 1 that the corrosion characteristics were good, but the conductivity characteristics were inferior to the corrosion resistance conductive coating material according to the present invention.

According to the results of Table 4, it is recognized that each of the corrosion-resistant conductive coating materials of Examples 2 to 6 according to the present invention retains good contact resistance even after 90 days of immersion test and has excellent current collecting characteristics. It was. On the other hand, in the coating materials prepared in Comparative Examples 2 and 4 in which the immersion test was conducted in the same manner, the corrosion of the substrate also progressed with time, and after 90 days, the contact resistance became 1000 mΩ · cm ² or more, and the conductive characteristics disappeared. Was. In the materials prepared in Comparative Examples 3 and 5, it was found from the results in Table 1 that the corrosion characteristics were good, but the conductivity characteristics were inferior to the corrosion resistance conductive coating material according to the present invention.

  According to FIG. 3, the IV characteristic curve of Example 5 showed good power generation characteristics. However, in Comparative Example 5, the resistance of the corrosion-resistant conductive coating material was slightly higher than that in Example 5, so that the current that can be extracted was It was found that the density was slightly reduced. Further, when comparing the IV characteristic curves after the continuous power generation test for 1000 hours, the performance was hardly deteriorated in Example 5, and the current collecting performance of the corrosion-resistant conductive coating material was maintained and excellent. The power generation characteristics were confirmed. On the other hand, in Comparative Example 5, the resistance of the corrosion-resistant conductive coating material tends to increase, and due to the influence, the current collecting performance is deteriorated, and the power generation characteristics are greatly reduced.

  The corrosion-resistant conductive coating material of the present invention is mainly used for a power supply roll of a plating apparatus and a metal separator for a fuel cell, but can be suitably used for an electrical contact, a terminal, an electrolytic anode, and the like.

The schematic diagram which shows the mechanism in which a precise | minute conductive polymer excellent in corrosion resistance deposits on a copper base | substrate by this invention. The figure which showed the contact resistance measuring method for measuring a current collection characteristic. It is a figure which shows the battery characteristic (IV characteristic curve) of the single cell using the separator manufactured according to Example 5 and Comparative Example 5. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Copper base body 2 Carboxylic acid copper particle 3 Conductive polymer particle doped with carboxylic acid anion 4 Conductive polymer particle doped with sulfonate anion 11 Load load device 12 Gold electrode 13 Carbon electrode 14 Conductive polymer coating Material

Claims (1)

Using an electrolytic solution containing a conductive polymer monomer, a carboxylic acid anion, and a sulfonic acid anion, and the carboxylic acid anion prepared at a concentration ratio (molar ratio) of 0.15 to 0.75 with respect to the sulfonic acid anion A method for producing a corrosion-resistant conductive coating material, comprising forming a conductive polymer layer on a copper substrate by electrolytic polymerization.

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