JP2002309175A - Electrolyte for forming polymer film and method for forming polymer film using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrolyte for electrolytic polymerization relieved from problems concerning workability, safety and hygiene heretofore caused by use of an alkylamine, a volatile liquid having a specific smell. SOLUTION: The electrolyte for forming a polymer film comprises a reagent capable of forming a complex with a metal constituting a main component of an electrode, and a polymerizable monomer, and has a hydrogen ion concentration index in the passivity range of the metal constituting the main component of the electrode, where the reagent is selected from at least one of a dicarboxylate, an α-hydroxycarboxylate, an α-amino acid and a nitrogen- containing heterocyclic compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrolytic solution used for coating a metal coil, a metal foil, a metal plate, a metal part and the like. In particular, the present invention relates to an electrolytic solution used for an organic polymer film formed by an electrolytic polymerization method.

[0002]

2. Description of the Related Art A polymer-coated metal material is provided with excellent properties of a polymer material, such as electrical insulation and corrosion resistance, to a metal. Widely used in the electronics field. As a method of coating a metal with a polymer film, after forming a polymer layer on the surface of the metal material by applying a polymer solution or dipping, baking or curing reaction by electron beam or ultraviolet light, strength, heat resistance and A method of imparting corrosion resistance is generally used.

[0003] On the other hand, as one of methods for selectively forming a polymer film on an electrically conductive substrate such as a metal,
Electropolymerization is mentioned. As a method of forming an insulating polymer thin film on a conductor by electrolytic polymerization, there is electrochemica.
Acta, Vol. 22, pp. 451-457, 1977, and Journal of Applied Electrochemistry, Vol. 9, pp. 483-493, 1979.

[0004]

There are two types of electrolytic polymerization, electrolytic oxidative polymerization in which electrolysis is carried out using a base material as an anode and the oxidized monomer is polymerized on the electrode, and the reverse, electrolytic reduction polymerization. The former is more widely practiced. When performing this electrolytic oxidation polymerization on metal, when the conductor is held at a high potential as an anode during electrolysis,
Depending on the hydrogen ion concentration of the electrolyte and the metal species, the passivation of the surface stops the electrolytic current, and as a result,
The formed polymer film is very thin and may not be practical.

As a method for solving these problems, a phenol derivative in which the 4-position is unsubstituted and the 2, 3, 5, and 6-positions are substituted or unsubstituted, and an alkaline aqueous solution containing an alkylamine are used. Discloses a method of forming an electropolymerized polymer film on a metal by performing an electrolytic oxidation polymerization of a phenol derivative (Japanese Patent Application Laid-Open No. 2000-2000).
-104014). In this method, a high affinity for transition metal ions is exerted on the metal surface passivated in an alkaline aqueous solution, and the alkylamine acts on the surface, thereby preventing the termination of the electrolytic current and allowing the electrolytic oxidation polymerization to proceed for a long time. It is thought that it is progressing over.

However, in the above-mentioned method, since a low molecular weight alkylamine, which is a volatile liquid having a peculiar odor, is used from the viewpoint of solubility, care must be taken from the viewpoint of workability and safety and health. .

[0007]

According to the present invention, dicarboxylates, α-carboxylates, etc. are used as compounds used in electrolytic polymerization, which have a complex forming ability with respect to the metal constituting the main component of the electrode and are easy to handle. Provided are an electrolyte for forming a polymer film using a compound selected from at least one of a hydroxycarboxylate, an α-amino acid and a nitrogen-containing heterocyclic compound, and a method for forming a polymer film using the same.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) First, a hydrogen ion concentration in a passive region of a metal containing a drug capable of forming a complex with a metal constituting a main component of an electrode and a polymerizable monomer is included. The polymer film forming electrolyte having an index will be described.

[0009] By using an aqueous solution having a hydrogen ion concentration index in the passive region of the metal formed by the polymer film, the dissolution of the metal can be suppressed. By dissolving the passivation layer formed on the metal surface to prevent the stop of the electrolytic current due to passivation, the electrolytic polymerization proceeds for a long time. As a result, a selective coating of the metal with the polymer coating is possible.

[0010] The oxidation state of the metal depends on the hydrogen ion concentration index of the electrolytic solution and the electrolytic potential. For this reason, it is necessary to adjust the composition of the aqueous solution used as the electrolytic solution so that the hydrogen ion concentration index is in a range where the main component of the metal is passivated at the potential during the electrolytic polymerization.

The above-mentioned aqueous solution uses water as a solvent,
Methanol, ethanol, 1-propanol, 2
-Alcohols such as propanol, 1-butanol, 2-butanol, tert-butyl alcohol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol and ethylene glycol, acetonitrile, dimethylformamide, dimethylsulfoxide, NMP, propylene carbonate And a polar solvent such as a polymerizable monomer and a complex-forming agent.

The polymerizable monomer is not particularly limited as long as it can be dissolved in an aqueous solution to form a polymer product by electrolytic polymerization. Examples thereof include heterocyclic compounds such as pyrrole and triazinethiol, aniline, and phenol. And aromatic compounds having a hetero substituent, derivatives thereof, and the like. The concentration of the polymerizable monomer is 0.01 to 10 mol / l, preferably 0.05 to 10 mol / l.
２2 mol / l.

The supporting electrolyte may be an acid such as sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid or hydrofluoric acid, or an alkali such as sodium hydroxide, potassium hydroxide, calcium hydroxide or metal alcoholate, or a chloride of an alkali metal. ,
It is appropriately selected from metal salts represented by perchlorates and carbonates according to the hydrogen ion concentration index required for the electrolytic solution. The concentration of the supporting electrolyte and the drug capable of forming a complex is preferably 0.01 to 10 mol / l, more preferably 0.05 to 2 mol / l.

The metal constituting the main component of the electrode is not particularly limited as long as it has a passivation region. Can be used. Also,
The electrodes containing these metals as main components include those obtained by coating these metals. For example, when the metal constituting the main component of the electrode is copper, electrolytic copper containing no metal element other than copper, oxygen-free copper, oxygen-free copper, etc. can be used as the electrode, and further, zinc, lead, tin, phosphorus, and the like. And those containing metal elements such as aluminum, nickel, silicon, manganese, nickel, beryllium, copper, cadmium and chromium can also be used.

The shape of the metal is not particularly limited, and a uniform polymer film can be formed on an object having a complicated shape such as a wire, a foil, a plate, a coil, an electronic component such as a motor, a capacitor, and a transformer. It can be formed on the surface. As the counter electrode of the electrolytic polymerization reaction, iron, stainless steel, aluminum, palladium, platinum, gold, carbon, etc.
Various things can be used.

In addition, in order to form a polymer film having more uniform and excellent physical properties, in combination with the present invention, a metal cleaning step such as pickling and electrolytic cleaning as a pre-treatment, a cleaning step as a post-treatment, heating and electron beam irradiation -It is advisable to carry out a curing step represented by ultraviolet irradiation.

(Embodiment 2) The total formation constant β _{m, n} is determined by a reaction (Equation 1) in which a complex MmLn is formed by a reaction between a metal ion M and a complexing agent L.

[0018]

(Equation 1)

It is represented as the following (Equation 2);

[0020]

(Equation 2)

Here, [M] is the metal ion concentration, [L]
Represents the complexing agent concentration, and [MmLn] represents the concentration of the complex.

The function of the agent capable of forming a complex is to suppress the stop of the electrolytic current by dissolving the passive layer on the metal surface. When a drug having a very small total formation constant of the complex formation reaction is used, the passivation layer cannot be dissolved, so that no electrolytic current flows, and as a result, the formation of the electropolymerized polymer film does not progress. Conversely, when a chemical having an extremely large total formation constant of the complex formation reaction is used, the metal elution reaction and the electropolymerization reaction compete with each other, making it difficult to form a polymer film efficiently. Dissolution proceeds not only in the active layer but also inside the metal to increase the damage, and there are problems such as an increase in metal ions eluted in the electrolytic solution, making it difficult to control the reaction.

From the above viewpoint, the drug used in the present invention is:
At least one of the group consisting of dicarboxylates, α-hydroxycarboxylates, α-amino acids, and nitrogen-containing heterocyclic compounds
Are preferred.

In general, many compounds having a large formation constant of a complex formation reaction with a metal have a polar substituent having strong coordination to the metal. The dicarboxylate ionizes in an aqueous solution to generate a divalent dicarboxylate anion. Since oxygen of two carboxyl groups of this dicarboxylate anion strongly coordinates to various transition metals to form a chelate complex,
The formation constant of the complex formation reaction with the metal is large.

The α-hydroxycarboxylate is ionized in an aqueous solution to produce an α-hydroxycarboxylate anion. In the α-hydroxycarboxylic acid anion, oxygen of a carboxyl group and oxygen of a hydroxyl group are strongly coordinated to various transition metals to form a chelate complex.

The α-amino acid is ionized in the aqueous solution, and generates a carboxyl anion, an amphoteric ion or an ammonium ion according to the hydrogen ion concentration index of the aqueous solution. Of these ions, the nitrogen of the amino group and the oxygen of the carboxyl group are strongly coordinated to various transition metal ions to form a chelate complex, so that many compounds have a large formation constant of the complex formation reaction with the metal.

The lone pair of a nitrogen atom present in a nitrogen-containing heterocyclic compound inherently exhibits strong coordination to various transition metals, and its cyclic structure suppresses the movement of the lone pair. Coordination is more enhanced. For this reason, many nitrogen-containing heterocyclic compounds have a large formation constant of a complex formation reaction with a metal.

The dicarboxylates include sodium oxalate, potassium oxalate, ammonium oxalate, sodium malonate, potassium malonate, ammonium malonate, sodium succinate, potassium succinate, ammonium succinate, sodium tartrate, potassium tartrate, and tartaric acid. Ammonium, sodium phthalate, potassium phthalate, or ammonium phthalate is preferred.

The type of the dicarboxylate used as the agent having a complex-forming ability is not particularly limited, but considering the use of an aqueous solution as the electrolyte,
From the viewpoint of solubility, the dicarboxylate used in the present invention preferably has a small molecular weight. In general, dialkali metal salts and diammonium salts of dicarboxylates show good solubility in water, and therefore, among the above compounds, those showing an appropriate complex formation constant for the metal to be coated are preferred. preferable.

Further, α-hydroxycarboxylates include sodium glycolate, potassium glycolate, ammonium glycolate, sodium lactate, potassium lactate,
Alternatively, ammonium lactate is preferred.

The kind of the α-hydroxycarboxylate used as the drug having a complex-forming ability is not particularly limited, but similar to the above-mentioned dicarboxylate,
From the viewpoint of solubility in an aqueous solution used as an electrolyte, those having a small molecular weight are preferred. In addition, generally, alkali metal salts and ammonium salts of α-hydroxycarboxylic acid show good solubility in water.Therefore, the α-hydroxycarboxylic acid salt used in the present invention is selected from the compounds shown above. Those exhibiting an appropriate complex formation constant for the metal to be coated are preferred.

The α-amino acid is preferably glycine, alanine or α-aminobutyric acid. This is because, as described above, those having a small molecular weight are preferable from the viewpoint of solubility in an aqueous solution used as an electrolytic solution. Therefore, the α-amino acid used in the present invention is preferably one of the above compounds that shows an appropriate complex formation constant for the metal to be coated.

Further, the nitrogen-containing heterocyclic compound is pyridine,
Preferred are imidazole, triazole, tetrazole, phenanthroline and derivatives thereof. Because
As described above, from the viewpoint of solubility in an aqueous solution used as an electrolytic solution, those having a small molecular weight are preferable. Therefore, the nitrogen-containing heterocyclic compound used in the present invention is preferably one of the above compounds that shows an appropriate complex formation constant for the metal to be coated.

(Embodiment 3) Copper is excellent in electric conductivity,
Widely used as conductive materials for electrical and electronic equipment such as conductors and coils. Many of the above-mentioned chemicals have a complex forming ability with copper, so that the dissolution of a passive layer formed of an oxide formed on the surface of a metal containing copper can be effectively advanced. By using the agent of the present invention, passivation of copper serving as a working electrode in the electrolytic solution is suppressed,
The polymerization reaction proceeds efficiently. As a result, a good electrolytic polymerized polymer film can be formed on the metal surface.

Examples of the electrode containing copper as a main component include electrolytic copper containing no metal element other than copper, oxygen-free copper, oxygen-free copper, zinc, lead, tin, phosphorus, aluminum, nickel, silicon, and the like.
Those containing manganese, nickel, beryllium, copper, cadmium, chromium and the like can be used. Further, the hydrogen ion concentration index of the aqueous solution is preferably from 7 to 12.

FIG. 1 shows the relationship between the oxidation state of copper, the hydrogen ion concentration index of the electrolytic solution, and the electrolytic potential prepared by Pourbaix (Atlas of Ele).
trochemical Equilibria i
n Aqueous Solution, quoted from 1966). In FIG. 1, the vertical axis represents the potential (V), the horizontal axis represents the pH of the electrolytic solution, and the dotted line a represents the equilibrium line of the hydrogen electrode reaction (E _h = −).
0.059 pH), dotted line b is the equilibrium line of the oxygen electrode reaction (E
_O2 = 1.23-0.059 pH). According to FIG. 1, when copper is kept in an oxidized state, the hydrogen ion concentration index of the electrolytic solution in which copper is passivated is in the range of 7 to 12. Therefore, when a metal having a composition of copper is used in the present invention, the film can be efficiently formed by setting the hydrogen ion concentration index of the electrolytic solution in the range of 7 to 12.

When a metal having copper as a composition is used, the supporting electrolyte may be an alkali such as sodium hydroxide, potassium hydroxide, calcium hydroxide, or a metal alcoholate, an alkali metal or an alkali metal chloride, or perchlorine. It may be selected from metal salts such as acid salts and carbonates. In the electrolyte, polymerizable monomers,
In addition to the supporting electrolyte and the agent capable of forming a complex, an additive for suppressing a change in the hydrogen ion concentration index may be added.

The polymerizable monomer is preferably a phenol derivative in which the 4-position is unsubstituted and the 2, 3, 5, and 6-positions are substituted or unsubstituted.

The phenol derivative which is unsubstituted at the 4-position and substituted or unsubstituted at the positions 2, 3, 5, and 6 is
The substituents at positions 3, 5, and 6 are not particularly limited,
For example, a saturated or unsaturated aliphatic or aromatic hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group, an alkoxyalkyl group, a carbonylalkyl group, a carbonyloxyalkyl group, an amide group, an aminocarbonylalkyl group, a hydroxyalkyl group Etc. can be used.

In particular, when a phenol derivative in which at least one of positions 2, 3, 5, and 6 is substituted and any of the substituents has two or more carbon atoms is used, the swelling of the resulting polymerization product As a result, a decrease in the electrolytic current caused by the insulating product is suppressed, so that a polymer film having a sufficient film thickness can be obtained, and the molecular structure of the polymer has a sterically bulky substituent in a side chain. It is particularly preferable because it has excellent flexibility because it is linear.

The type of the substituent having two or more carbon atoms is not particularly limited, and examples thereof include an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group and a t-butyl. Saturated alkyl group such as group, unsaturated alkyl group such as vinyl group, allyl group, allenyl group, propargyl group, aromatic hydrocarbon group such as phenyl group, alkoxy group, carbonylalkyl group, carbonyloxyalkyl group, amide Substituents such as groups can be used. In addition, the types of the substituents other than the substituent having two or more carbon atoms are not particularly limited.

The electrode potential of the working electrode in the electropolymerization reaction may be determined based on the chemical structure of the phenol derivative used in which the 4-position is unsubstituted and the substituted, unsubstituted 2, 3, 5, and 6 positions, the composition of the electrolytic solution, and the like. It depends on. At this time, the voltage applied between the electrodes is not particularly limited.

The phenol derivative is preferably 2-allylphenol. When electrolytic polymerization is carried out using 2-allylphenol as a polymerizable monomer, a polymer film having a reactive carbon-carbon unsaturated bond in a side chain is obtained. An initiator such as a peroxide, an azo compound, or a vulcanizing agent is added to the polymer film, if necessary, and post-treatment such as heating or irradiation with an electron beam or ultraviolet light is performed after the completion of the electrolytic polymerization. The radical crosslinking reaction of the carbon-carbon unsaturated bond in the chain proceeds. As a result, it is possible to obtain a polymer film having no defect, high strength, and excellent physical properties such as electrical insulation.

As the polymerizable monomer, pyrrole and its derivatives are preferable. Electrolytic oxidation of pyrrole and its derivatives forms a conductive polymer film on the working electrode. Since the product is conductive, the polymer film can be controlled by the applied voltage and the electrolysis time.

The type of the pyrrole derivative is not particularly limited as long as it shows solubility in the aqueous solution to be used, but 2-pyrrolecarboxylic acid, 2-pyrrolecarboxylic acid ester, indole and the like can be used.

The conductivity of an electropolymerized polymer film obtained from pyrrole or a derivative thereof is generally caused by charge transfer by a dopant component contained in the film. For this reason, the dopant is desorbed from the polymer film,
By reducing the conductivity of the polymer coating, it is also possible to make the coating on the metal insulative. Examples of the method for removing the dopant include application of an electric field having a polarity opposite to that of electrolysis, contact with a solution of a compound having a reducing anion such as thiosulfate and hyposulfite as a component, and a combination of these methods. .

As the polymerizable monomer, aniline and its derivatives are preferable. A conductive polymer film is formed on the working electrode by electrolytic oxidation of aniline and its derivatives. Since the product is conductive like pyrrole, the thickness of the polymer film can be controlled by the applied voltage and the electrolysis time.

The type of the aniline derivative is not particularly limited as long as it shows solubility in the aqueous solution to be used, but 2-methylaniline, 2-aminobenzoic acid, o-anisidine and the like can be used.

The conductivity of the electropolymerized polymer film obtained from aniline and its derivatives is due to the charge transfer by the dopant component contained in the film as described above. For this reason, it is possible to desorb the dopant from the polymer film and to insulate the film formed on the metal by the same method as when pyrrole and its derivatives are used.

(Embodiment 4) A metal having an electrically insulating coating portion refers to an enameled wire having an insulating coating on the surface by applying a so-called varnish, a metal having an oxide film formed on the surface, or the like. When an insulating defect exists in these surface coating portions, the defective portion can be electrically connected to the outside, and is used as an electrode. By performing the coating method by electrolytic polymerization described above, a polymer film can be selectively formed on the defective portion, and an insulating film can be formed.

Further, by using the above-mentioned electrolytic solution, the film thickness can be from submicron to several μm or tens of μm.
, Etc. can be formed. Since the coating has no defects and excellent adhesion to the metal, it is possible to manufacture an insulating coating metal with higher productivity and reliability. For example, when the present invention is applied to an insulated wire,
The thickness of the insulating coating can be reduced as compared with a conventional coated electric wire. Therefore, by applying this electric wire to an electronic component, it is possible to contribute to miniaturization and high efficiency of the electronic device.

[0052]

EXAMPLES (Example 1) A copper plate (5 x 60 x 0.1 mm strip) was used as an electrode. The electrolyte was prepared by dissolving 0.7 mol of 2-allylphenol, 0.7 mol of potassium hydroxide, and 0.3 mol of potassium tartrate in an aqueous solution of water: methanol = 75: 25% by volume. , The total volume was 50 ml (hydrogen ion concentration index: 11.
7). Here, the logarithmic value of the total formation constant of the complex formation reaction of copper with the tartrate anion derived from potassium tartrate in water is 6.51.

A strip-shaped copper plate and a platinum plate were immersed in the electrolytic solution, and a DC voltage of 3 V was applied between the two metal plates so that the potential of the copper electrode became an anode, and electrolysis was performed for 5 minutes. Thereafter, the copper electrode was taken out, sufficiently washed with water, and heat-treated at 150 ° C. for 1 hour.

The formation of the coating was confirmed by the amount of change in weight before and after electrolytic polymerization. That is, the weight of the film formed on the electrode by electrolytic polymerization was divided by the specific gravity of the polymer of allylphenol, and the value was divided by the immersion area of the copper plate. As a result, the film thickness formed on the electrode was 8 μm. Therefore, it can be said that the thickness of the film formed in this example has a sufficient thickness.

The electrical insulation of the electrode formed in this example was measured by forming a gold film on the film, and found to be 5 × 10 ¹³ Ωcm. Thus, it was confirmed that the film formed by the method of this example can be sufficiently used as an insulating film.

(Example 2) Copper plate (5 × 60 × 0.1 mm)
Was used as an electrode. The electrolyte was prepared by dissolving 0.7 mol of 2-allylphenol, 0.7 mol of potassium hydroxide, and 0.3 mol of sodium lactate in an aqueous solution of water: methanol = 75: 25% by volume. , Total volume 50 ml (hydrogen ion concentration index 11.9)
Created as. Here, the logarithm of the total formation constant of the complex formation reaction of copper with the lactate anion derived from sodium lactate in water is 4.85.

A strip-shaped copper plate and a platinum plate were immersed in this electrolytic solution, and a DC voltage of 3 V was applied between the two metal plates so that the potential of the copper electrode became an anode, and electrolysis was performed for 5 minutes. Thereafter, the copper electrode was taken out, sufficiently washed with water, and heat-treated at 150 ° C. for 1 hour.

The thickness of the film formed in this example was measured in the same manner as in Example 1, and it was 3.5 μm. Therefore, it can be said that the thickness of the film formed in this example has a sufficient thickness.

The electrical insulation of the electrode formed in this example by forming a gold film on the film was 1 × 10 ¹³ Ωcm. Thus, it was confirmed that the film formed by the method of this example can be sufficiently used as an insulating film.

Example 3 Copper plate (5 × 60 × 0.1 mm)
Was used as an electrode. The electrolyte was prepared by dissolving 0.7 molar 2-allylphenol, 0.7 molar potassium hydroxide, and 0.3 molar glycine in an aqueous solution of water: methanol = 75: 25% by volume, The total volume was prepared as 50 ml (hydrogen ion concentration index: 9.3). Here, the logarithmic value of the total formation constant of the complex formation reaction of glycine with copper in water is 12.2.

A strip-shaped copper plate and a platinum plate were immersed in the electrolytic solution, and a DC voltage of 3 V was applied between the two metal plates so that the potential of the copper electrode became an anode, and electrolysis was performed for 5 minutes. Thereafter, the copper electrode was taken out, sufficiently washed with water, and heat-treated at 150 ° C. for 1 hour.

The thickness of the film formed in this example was measured in the same manner as in Example 1, and it was 2.8 μm. Therefore, it can be said that the thickness of the film formed in this example has a sufficient thickness.

The electrical insulation of the electrode formed in this example by forming a gold film on the film was 2 × 10 ¹³ Ωcm. Thus, it was confirmed that the film formed by the method of this example can be sufficiently used as an insulating film.

Example 4 Copper plate (5 × 60 × 0.1 mm)
Was used as an electrode. The electrolytic solution is obtained by dissolving 0.7 mol of 2-allylphenol, 0.7 mol of potassium hydroxide, and 0.3 mol of pyridine in an aqueous solution of water: methanol = 75: 25% by volume, The total volume was made 50 ml (hydrogen ion concentration index 10.8). Here, the logarithmic value of the total formation constant of the complex formation reaction of pyridine with copper in water is 10.2. A strip-shaped copper plate and a platinum plate were immersed in the electrolytic solution, and a DC voltage of 3 V was applied between the two metal plates so that the potential of the copper electrode became the anode, and electrolysis was performed for 5 minutes. Thereafter, the copper electrode was taken out, sufficiently washed with water, and heat-treated at 150 ° C. for 1 hour.

When the thickness of the film formed in this example was measured in the same manner as in Example 1, it was 10 μm. Therefore, it can be said that the thickness of the film formed in this example has a sufficient thickness.

The electrical insulation of the electrode formed in this example by forming a gold film on the film was 1 × 10 ¹⁴ Ωcm. Thus, it was confirmed that the film formed by the method of this example can be sufficiently used as an insulating film.

Example 5 A copper plate (5 × 60 × 0.1 mm)
Was used as an electrode. The electrolyte was prepared by dissolving 0.5 mol of pyrrole, 0.1 mol of potassium perchlorate, and 0.3 mol of potassium tartrate in an aqueous solution of water: methanol = 75: 25% by volume. The volume was set to 50 ml (hydrogen ion concentration index: 10.2). A strip-shaped copper plate and a platinum plate were immersed in this electrode, and a DC voltage of 3 V was applied between the two metal plates so that the potential of the copper electrode became an anode, and electrolysis was performed for 5 minutes. Then, the copper electrode was taken out, washed with a 0.1 molar sodium thiosulfate aqueous solution, and heated at 150 ° C. for 1 hour.

When the film thickness of the film formed in this example was measured in the same manner as in Example 1, it was 2 μm. Therefore,
It can be said that the thickness of the film formed in this example has a sufficient thickness.

Further, the electrical insulation of the electrode formed in this example by forming a gold film on the film was 2 × 10 ¹³ Ωcm. Thus, it was confirmed that the film formed by the method of this example can be sufficiently used as an insulating film.

Example 6 A copper plate (5 × 60 × 0.1 mm)
Was used as an electrode. The electrolyte solution is 0.5 molar aniline, 0.1 molar potassium hydroxide,
And 0.3 molar potassium tartrate are dissolved in an aqueous solution of water: methanol = 75: 25 vol.
It was prepared as 0 ml (hydrogen ion concentration index: 11.9). A strip-shaped copper plate and a platinum plate were immersed in the electrolytic solution, and a DC voltage of 3 V was applied between the two metal plates so that the potential of the copper electrode became the anode, and electrolysis was performed for 5 minutes. Next, the copper electrode was taken out, washed with 0.1 N hydrochloric acid, and heated at 150 ° C. for 1 hour.

The thickness of the film formed in this example was 3 μm when measured in the same manner as in Example 1. Therefore, it can be said that the thickness of the film formed in this example has a sufficient thickness.

The electrical insulation of the electrode formed in this example by forming a gold coating on the coating was 1.5 × 10 ¹³ Ωcm. This allows
It was confirmed that the film formed by the method of this example can be sufficiently used as an insulating film.

(Embodiment 7) In this embodiment, it will be described that a polymer film is selectively formed on a part of an electrode by using the electrolytic solution of the present invention.

An enamel-coated lead wire (diameter 1 mm) has a diameter 2
After forming an annular shape of cm, a part of the enamel coating was scraped off with sandpaper to prepare an electrode having an insulating defect portion. As an electrolyte, 0.7 molar 2-allylphenol, 0.7 molar potassium hydroxide, and 0.3 molar potassium tartrate were dissolved in an aqueous solution of water: methanol = 75: 25% by volume. One used. The electrolyte was added to the above electrode and a 5 × 60 electrode as a counter electrode.
A 0.1 mm × 0.1 cm strip-shaped platinum plate was immersed, and a DC voltage of 3 V was applied between both electrodes to perform electrolysis for 10 minutes. After the electrolysis was completed, the electrode was sufficiently washed with water and heat-treated at 150 ° C. for 1 hour. This confirmed that the black polymer film was selectively formed on the portion of the electrode where the enamel film was removed. The electrode and the platinum electrode were immersed in a 0.1 molar sodium chloride aqueous solution, and the conduction between the two electrodes was examined. As a result, the insulation was good.

Comparative Example 1 A copper plate (5 × 60 × 0.1 mm)
Was used as an electrode. The electrolyte was prepared by dissolving 0.7 mol of 2-allylphenol, 0.7 mol of potassium hydroxide, and 0.3 mol of imidazole in an aqueous solution of water: methanol = 75: 25% by volume, The total volume is 50 ml (hydrogen ion concentration index 10.8)
Created as. Here, the logarithmic value of the total formation constant of the complex formation reaction of imidazole with copper in water is 30. Immerse a strip of copper plate and platinum plate in this electrolyte,
3V between both metal plates so that the potential of the copper electrode becomes the anode
, And electrolysis was performed for 5 minutes.

When the copper electrode was taken out and sufficiently washed with water, the surface of the copper plate was etched, and no polymer film was formed.

Comparative Example 2 Copper plate (5 × 60 × 0.1 mm)
Was used as an electrode. The electrolyte was prepared by dissolving 0.7 mol of 2-allylphenol, 0.7 mol of potassium hydroxide, and 0.3 mol of acetic acid in an aqueous solution of water: methanol = 75: 25% by volume, The total volume was prepared as 50 ml (hydrogen ion concentration index: 9.8). Here, the logarithmic value of the total formation constant of the complex formation reaction of acetic acid with copper in water is 3.2. A strip-shaped copper plate and a platinum plate were immersed in this electrolytic solution, and a DC voltage of 3 V was applied between the two metal plates so that the potential of the copper electrode became the anode, and electrolysis was performed for 5 minutes. When the copper electrode was taken out and washed sufficiently with water, the surface of the copper plate was exposed while maintaining the metallic luster, and no polymer film was formed.

(Comparison results between the present embodiment and the comparative example) The results of the above embodiment and the comparative example are summarized in the following (Table 1).

[0079]

[Table 1]

Examples of the chemicals used in the examples were potassium tartrate as a dicarboxylate (Examples 1, 5, and 6), sodium lactate as an α-hydroxycarboxylic acid (Example 2), and glycine as an α-amino acid (Example 2). Example 3), pyridine (Example 4) which is a nitrogen-containing heterocyclic compound was used. On the other hand, in the comparative example, an example in which imidazole (Comparative Example 1) and acetic acid (Comparative Example 2) were used as examples of the electrolytic solution using a chemical other than the above.

Since potassium tartrate, potassium lactate, and glycine used as drugs in this example are solid, they are easier to handle than liquids, and glycine is an amino acid, so it is safe to handle. Therefore, according to the present invention, an electrolytic solution can be prepared and used more easily and safely than a conventional method using a volatile liquid.
In addition, it was confirmed that an electrode having a sufficient insulating property was able to be prepared using the electrolyte solution thus prepared.

[0082]

As described above, an electrolyte for forming a polymer film using a compound which is easy to handle as a chemical having an ability to form a complex with the metal constituting the main component of the electrode, and an electrolyte for forming the polymer film. It was possible to provide a polymer coating method using a liquid.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the oxidation state of copper and the hydrogen ion concentration index and electrolytic potential of an electrolytic solution.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C25D 9/02 C25D 9/02 13/08 13/08 F term (reference) 4J038 DC001 DJ001 DK001 HA096 HA106 HA156 HA176 HA186 HA236 HA256 HA266 HA336 HA366 HA416 JA19 JA20 JA44 JA48 JA52 JB08 JB10 JB18 JB28 JB29 JB32 JB35 JB37 JC11 JC27 KA12 MA08 NA17 NA23 NA25 PA21 PC02

Claims (6)

[Claims] 1. An electrode comprising a drug capable of forming a complex with a metal constituting a main component of an electrode and a polymerizable monomer, and having a hydrogen ion concentration index in a passive region of the metal constituting the main component of the electrode. An electrolyte for forming a polymer film having a function of forming a polymer film on the surface of the electrode by electrolytic polymerization, wherein the agent comprises a dicarboxylate, an α-hydroxycarboxylate, an α-amino acid, and a nitrogen-containing salt. An electrolyte for forming a polymer film, selected from at least one of heterocyclic compounds. 2. The electrolytic solution for forming a polymer film according to claim 1, wherein the metal constituting the main component of the electrode is copper. 3. The polymerizable monomer is a phenol derivative which is unsubstituted at the 4-position and is substituted or unsubstituted at the 2, 3, 5, 6-positions, or a pyrrole or a pyrrole derivative, or an aniline or an aniline derivative. The electrolytic solution for forming a polymer film according to claim 1 or 2, wherein: 4. The electrolytic solution according to claim 3, wherein the phenol derivative is 2-allylphenol. 5. A method for forming a polymer film, comprising: a step of immersing a metal in the electrolytic solution for forming a polymer film according to any one of claims 1 to 4; and a step of performing electropolymerization of the drug using the metal as an electrode. Method. 6. The method according to claim 5, wherein a supporting electrolyte is added to the electrolyte for forming a polymer film so that the hydrogen ion concentration index is in the range of 7 to 12.