JP2002020894A - Method for coating metal and insulator-coated metallic conductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a flawless coating excellent in adhesion to a metallic conductor is conventionally difficult to form due to the effect of the oxide layer or surface-treated layer of the conductor surface, when a polymer film is formed on the metallic conductor by electrolytic polymerization to coat the conductor. SOLUTION: Electrolysis is conducted with the metallic conductor as an anode to oxidize and dissolve the conductor, then electrolysis is performed with the oxidized and dissolved conductor as a working electrode in an aqueous solution containing a polymerizable monomer, a supporting electrolyte and an alkylamine to form a polymer film on the conductor, and the conductor is coated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method 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 organic polymer film formed by an electrolytic polymerization method and a method for forming the same, and a method for insulating a metal material using the same and an insulating coated metal conductor.

[0002]

2. Description of the Related Art By forming a polymer coating on a metal surface, the excellent properties of a polymer material such as electrical insulation and corrosion resistance are imparted to the metal. Such a polymer-coated metal material is widely used in the field of electronics as a conductive wire, an electronic component, an exterior member, and the like. As a method of coating a metal with a polymer film, a method of applying a polymer solution to a metal material, or dipping the metal material in the polymer solution, followed by baking or a curing reaction using an electron beam or ultraviolet light is generally performed. is there.

[0003] One of the techniques for forming a polymer thin film on a metal electrode is an electrolytic polymerization method. A method for forming an insulating polymer thin film on a conductor by electrolytic polymerization is described in the literature, Electrokimika Actor, Vol. 22, pp. 451-457,
977 (Electrochimica Acta, 22,451-457 (1977))
And Journal of Applied Electrochemistry, Vol. 9, pp. 483-493, 1979 (Jornal
of Applied Electochemistry, 9,483-493 (1979)).

[0004]

In recent years, with the rapid progress of miniaturization and high efficiency of electronic equipment, further miniaturization of materials and parts used is indispensable. Therefore, it is desired that the polymer coating formed on the metal conductor be made as thin as possible. However, it is difficult to stably form a uniform thin film on the end of a coil having a flat plate or a rectangular cross section by a conventional method of forming a polymer thin film by solution coating or dip. Therefore, for example, a rectangular coil having an insulating thin film having a thickness of several μm or less has not been developed at present.

[0005] In recent years, efforts to save resources in the manufacturing process have been promoted due to increasing awareness of the global environment. If the technology to selectively form a uniform polymer coating only on the metal conductor part is established, the amount of the polymer coating attached to unnecessary parts other than the metal conductor will decrease, and the chemicals necessary for forming the thin film will be removed. The amount of use can be reduced, leading to resource saving in the process. In addition, if it is possible to form an insulating polymer coating only on insulation defects of conductive wires and electronic components, defective products can be reused. But,
It is difficult to achieve selective coating formation by a conventional solution coating or dipping method.

As a means for solving these problems, it is conceivable to selectively form a polymer film only on the surface of a metal conductor by performing an electrolytic polymerization method using a metal conductor as an electrode. However, since the growth of the polymer film by the electrolytic polymerization method is affected by the shape and cleanliness of the oxide layer metal surface on the metal surface, it has been conventionally difficult to form a defect-free thin film.

[0007]

SUMMARY OF THE INVENTION In order to solve these problems, the metal coating method of the present invention comprises contacting a metal conductor as an electrode with an electrolyte, and applying a voltage so that the metal conductor acts as an anode. Applying and oxidizing and dissolving the surface of the metal conductor, and bringing the metal conductor subjected to the electrolysis into contact with an aqueous solution containing a polymerizable monomer, a supporting electrolyte and an alkylamine, and using the metal conductor as an electrode, A step of forming a polymer film on the surface of the metal conductor by performing electrolytic polymerization of the conductive monomer.

[0008] A second method of coating a metal according to the present invention is as follows.
Bringing the metal conductor into contact with the electrolytic solution as an electrode, applying a voltage so that the metal conductor acts as an anode, and oxidizing and dissolving the metal conductor to roughen the surface of the metal conductor; The metal conductor having been subjected to the surface roughening is brought into contact with an aqueous solution containing a polymerizable monomer, a supporting electrolyte and an alkylamine, and the metal conductor is used as an electrode to perform electrolytic polymerization of the polymerizable monomer. A step of forming a polymer film on the surface.

[0009] A third method of coating a metal according to the present invention comprises:
A solution containing sulfuric acid or hydrochloric acid is used as the electrolytic solution in the oxidative dissolution step.

A fourth aspect of the present invention is a method for coating a metal,
A solution containing sodium hydroxide or potassium hydroxide is used as the electrolytic solution in the oxidative dissolution step.

[0011] The metal coating method according to a fifth aspect of the present invention includes:
A solution containing ammonia or an alkylamine is used as the electrolytic solution in the oxidative dissolution step.

A sixth aspect of the present invention is a method for coating a metal,
The method of electrolysis is characterized in that the potential of the metal conductor with respect to the standard electrode is kept constant.

Further, a metal coating method according to a seventh aspect of the present invention comprises:
The metal conductor has copper as a composition.

An eighth method of coating a metal according to the present invention comprises the steps of:
As a polymerizable monomer, the 4-position is unsubstituted, and 2,
It is characterized in that a phenol derivative in which the 3, 5, and 6 positions are substituted or unsubstituted is used.

A ninth aspect of the present invention is a method for coating a metal,
As the polymerizable monomer, the 4-position is unsubstituted and 2, 3,
One or more of the 5- and 6-positions are substituted, and any of the substituents is a phenol derivative having two or more carbon atoms.

In a tenth aspect of the present invention, there is provided a method of coating a metal according to the present invention, wherein the 4-position is unsubstituted, and at least one of positions 2, 3, 5, and 6 is substituted, and one of the substituents is carbon. As a phenol derivative having two or more atoms, 2-allylphenol, 2- (2-propenyl) phenol or 2-allyl-6-methylphenol is used.

An eleventh metal coating method according to the present invention is characterized in that pyrrole and its derivatives are used as the polymerizable monomer.

The twelfth metal coating method of the present invention is characterized in that aniline and its derivatives are used as the polymerizable monomer.

A thirteenth metal coating method according to the present invention is characterized in that the metal conductor has an electrically insulating coating portion, and that a coating is formed at a defective portion of the coating portion by the coating method. Features.

According to a fourteenth aspect of the present invention, there is provided the insulating-coated metal conductor, wherein a coating is formed on a part or the entire surface of the metal conductor by the coating method.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a metal coating method and an insulated metal conductor according to the present invention will be described.

First, the first invention is a step of bringing a metal conductor into contact with an electrolytic solution as an electrode, applying a voltage so that the metal conductor acts as an anode, and oxidizing and dissolving the surface of the metal conductor. The metal that has been subjected to the electrolysis is brought into contact with an aqueous solution containing a polymerizable monomer, a supporting electrolyte and an alkylamine, and the metal is used as an electrode to perform electrolytic polymerization of the polymerizable monomer, whereby a polymer film is formed on the metal surface. A method for coating a metal, which includes a step of forming a metal, will be described.

The electrolytic polymerization method is a method in which an active species is generated electrically on the surface of a working electrode, and a polymer is obtained by a coupling reaction of the active species. If the resulting polymer is insoluble in the electrolyte, it will deposit as a film on the electrode. The state of the formed polymer film is greatly affected by the state of the working electrode. When a metal is used as the working electrode, its surface is usually covered with an oxide layer. Further, from the viewpoint of rust prevention and the like, surface treatment such as application of oils and fats or chemicals is often performed. Their presence acts to reduce the current efficiency during electrolysis and hinders the formation of a uniform electropolymerized polymer film.

When electrolysis is performed using a metal as an electrode, the oxidation state differs depending on the potential of the metal and the hydrogen ion index of the electrolyte. Depending on the type of metal, when it is kept at a high potential in an electrolyte having a hydrogen ion index within a certain range, it is oxidized to metal cations or metal complex ions and dissolved in the electrolyte. As a result, the oxide layer covering the metal surface is dissolved, and at the same time, the surface treatment film and the attached dirt are decomposed or removed. Therefore, a clean and uniform metal surface can be obtained by the oxidative dissolution process using this electrolysis.

Before the step of forming a polymer film by electrolytic polymerization, the metal layer to be coated is subjected to the above-described oxidative dissolution step by electrolysis, whereby an oxide layer and a surface treatment layer that reduce current efficiency are removed. Since the electrolytic reaction on the surface is promoted, it is possible to form a polymer film having no defects, excellent adhesion to metal, and a large film thickness.

The composition of the electrolytic solution and the hydrogen ion index in the case of performing the oxidative dissolution process differ depending on the composition and shape of the metal used, the surface condition before the process is performed, and the like. Usually, acids such as sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid and hydrofluoric acid, alkalis such as potassium hydroxide, sodium hydroxide and calcium hydroxide, sodium chloride, potassium chloride, ammonium chloride, sodium orthosilicate, sodium metasilicate, A water or organic solvent solution of a metal salt such as trisodium phosphate and sodium carbonate can be used. If necessary, additives such as a chelating agent, a surfactant, and an inhibitor may be mixed.

The electrolytic potential in the oxidative dissolution step is appropriately set according to the composition of the metal used. The electrolysis time is determined according to the composition of the electrolyte, the electrolysis potential, the state of the metal surface before electrolysis and the required cleanliness, and is not particularly limited.

The polymerizable monomer used for forming the polymer film is not particularly limited as long as it can be dissolved in an aqueous solution to form a polymer product by electrolytic polymerization.
For example, heterocyclic compounds such as pyrrole and triazinethiol, aromatic compounds having a hetero substituent such as aniline and phenol, and derivatives thereof can be used. The supporting electrolyte is dissolved in the aqueous solution used,
There is no particular limitation as long as it generates ions in the solution.

Examples of the alkylamine include methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, tertiary butylamine, dimethylamine, diethylamine, di (n-propyl) amine, and di (n-propylamine). Isopropyl) amine, di (n-butyl) amine, di (isobutyl) amine, di (tert-butyl) amine, trimethylamine, triethylamine, tri (n-propyl) amine,
Tri (isopropyl) amine, tri (n-butyl) amine, tri (isobutyl) amine, tri (tert-butyl) amine, or mono-, di-, or trialkylamine having an alkyl group larger than these, or ethanolamine And substituted alkylamines such as diethanolamine and triethanolamine.

At this time, considering the solubility in an aqueous solution described later, a mono- or dialkylamine having a small alkyl chain is suitable, and for example, ethylamine, dimethylamine, and diethylamine can be used. For the same reason, alkylamines having a hydrophilic substituent such as ethanolamine, diethanolamine, and triethanolamine are also preferable.

Further, the 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 the like, to which a polar solvent such as is added as necessary.

The concentration of the polymerizable monomer is from 0.01 to 10 mol /
l, preferably 0.05 to 2 mol / l. The concentration of the supporting electrolyte is 0.01 to 10 mol / l, preferably 0.05 to 2 mol / l.
It is. The concentration of the alkylamine is between 0.05 and 1 mol / l.

The composition of the metal is not particularly limited. Gold, silver,
A metal foil containing copper, platinum, palladium, aluminum, zinc, tin, nickel, iron, titanium, palladium, indium, or the like as a composition can be used. In addition, the shape of the metal is not particularly limited, other than wires, foils, plates, coils,
It is possible to form a uniform polymer film on the surface of an object having a complicated shape, such as an electronic component such as a motor, a capacitor, and a transformer. Various electrodes such as iron, stainless steel, aluminum, palladium, platinum, gold, and carbon can be used as the counter electrode for the electrolytic polymerization reaction.

Next, according to the second aspect of the present invention, the metal conductor is brought into contact with an electrolytic solution as an electrode, a voltage is applied so that the metal conductor acts as an anode, and the metal conductor is oxidized and dissolved. Roughening the surface of the metal conductor, and contacting the roughened metal conductor with an aqueous solution containing a polymerizable monomer, a supporting electrolyte and an alkylamine, and using the metal conductor as an electrode, A method for coating a metal, which includes a step of forming a polymer film on the surface of the metal conductor by performing electrolytic polymerization of a monomer, will be described.

In the above-described oxidative dissolution step by electrolysis, the surface roughness of the metal conductor after the oxidative dissolution step can be controlled by appropriately selecting conditions such as the composition of the electrolytic solution, the electrolysis time, and the processing temperature. It is possible. Perform the oxidative dissolution process under appropriate conditions, for the metal conductor roughened surface,
When the polymer film is formed by the above-described electrolytic polymerization, the adhesion between the polymer film formed by the development of the anchor effect and the metal conductor is further improved.

Next, a metal coating method according to a third aspect of the present invention, which comprises using a solution containing sulfuric acid or hydrochloric acid as the electrolytic solution in the oxidation dissolution step, will be described.
Since sulfuric acid and nitric acid have excellent ability to dissolve metal oxides, the oxidative dissolution step can be performed quickly and efficiently. In addition, the cost is low, and simple equipment can be used for the process, so that the cost can be reduced.

The concentrations of sulfuric acid and hydrochloric acid are appropriately set according to the composition, shape and surface condition of the metal used. If necessary, additives such as an inhibitor, an oxidizing agent, and a surfactant may be added to the electrolytic solution. It is desirable that the temperature of the electrolytic solution is in the range from room temperature to 80 ° C.

Next, a metal coating method according to a fourth aspect of the present invention, which comprises using a solution containing sodium hydroxide or potassium hydroxide as the electrolytic solution in the oxidation dissolution step, will be described.

When a solution containing sodium hydroxide or potassium hydroxide is used in the oxidative dissolution step, the dissolution of the metal base does not proceed easily as compared with the acidic solution.
Excellent dimensional stability after process. Further, the effect of removing dirt due to organic substances such as oils and fats attached to the metal surface is great. This is because the basic solution has a high permeability to fats and oils, and can further decompose fats and oils by a saponification reaction.

Further, since sodium hydroxide and potassium hydroxide have high electric conductivity, the oxidative dissolution step can be carried out quickly and efficiently.

The concentration of the alkali metal or alkaline earth metal hydroxide is appropriately set in accordance with the composition, shape, surface state, etc. of the metal used. Also, if necessary,
A basic metal salt such as sodium carbonate, sodium silicate and sodium phosphate, a surfactant and the like may be added. The temperature of the electrolyte is below the boiling point, preferably from 60 ° C to 100 ° C.
Heating in the range of ° C. can shorten the process time.

Next, a metal coating method according to a fifth aspect of the present invention, which comprises using a solution containing ammonia or an alkylamine as an electrolytic solution in the oxidation dissolution step, will be described.

Ammonia and amines exhibit large coordination abilities due to the lone pair of electrons of the nitrogen atom, especially for transition metal ions. When complex ions generated by coordination of ammonia or amine show solubility in a solution, the addition of these promotes dissolution of the metal. This is due to the fact that the complex ions are usually stabilized as compared to the original metal ions.

By using a solution of ammonia or amine as the electrolytic solution in the oxidation dissolution step, stabilization of metal ions by this complex ion formation reaction proceeds, and dissolution of the metal conductor surface is promoted. As a result, it is possible to reduce the time required for the oxidative dissolution step and the applied voltage.

Any amine can be used as long as the amine itself and the complex ion formed between the amine and the metal ion show solubility in the solvent of the electrolytic solution. For example, methylamine, ethylamine, n-propylamine, isopropylamine, dimethylamine, diethylamine, di (n-propyl) amine, di (isopropyl)
Amines, trimethylamine, triethylamine, tri (n-propyl) amine, tri (isopropyl) amine, or mono-, where the alkyl group is larger than these,
Di- or trialkylamine, ethylenediamine, 1,3-propanediamine, phenylenediamine, diethylenetriamine, ethylenediaminetetraacetic acid, ethanolamine, diethanolamine, triethanolamine and the like can be used. The concentration of ammonia or amine is 0.01 to 10 mol / l, preferably 0.05 to 2 mol / l.
l.

Next, a metal coating method according to a sixth aspect of the present invention, which is characterized in that a potential of a metal conductor with respect to a standard electrode is kept constant, will be described.

As described above, the oxidation state of the metal surface is
It depends on the potential of the metal and the hydrogen ion index of the electrolyte. If the potential of the metal conductor changes during the electrolysis step and is out of the range where metal cations or metal complex ions are eluted, the metal surface is not sufficiently cleaned by elution of these ions and subsequently formed. This causes a reduction in the uniformity, adhesion, and film thickness of the electropolymerized polymer film.

In the electrolysis step, by keeping the potential of the metal conductor with respect to the standard electrode constant, the elution reaction of metal cations or metal complex ions from the metal surface can be easily controlled, and the metal surface can be cleaned. Can be performed sufficiently. When a metal is used as the conductor and the potential with respect to the standard electrode is kept constant, the elution amount of the ions may be considered to be proportional to the electrolysis time. Therefore, it is possible to control the cleanliness of the metal conductor surface by adjusting the electrolysis time. The holding potential and the electrolysis time are set according to the type of metal used as the conductor, and are not particularly limited.

Next, a metal coating method according to a seventh aspect of the present invention, wherein the metal conductor has copper as a composition, will be described.

Copper has excellent electrical conductivity and is most commonly used as a conductive material for electrical and electronic equipment such as conductive wires and coils. Since copper has a higher affinity for alkylamines than other metals, activation of the passivation layer made of an oxide formed on the surface of the metal conductor with alkylamines proceeds more effectively. That is, when a polymer film is formed on copper by electrolytic polymerization, passivation of the copper foil serving as a working electrode in the electrolytic solution is suppressed, and the polymerization reaction proceeds efficiently. As a result, a good polymer film can be formed.

As the metal conductor having copper as a composition,
In addition to electrolytic copper, metal-free copper, oxygen-free copper and oxygen-free copper that do not contain metal elements other than copper, zinc, lead, tin, phosphorus, aluminum, nickel, silicon, manganese, nickel, beryllium, copper, cadmium, It is also possible to use a metal conductor containing chromium or the like.

For a metal conductor having copper as a composition,
When performing the above-mentioned electrolysis step, the hydrogen ion index of the electrolytic solution used is set to 4 or less to 12 or more. Acids such as sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid and acetic acid, and alkalis such as potassium hydroxide, sodium hydroxide and calcium hydroxide can be used as the electrolyte. The potential of the metal foil with respect to the standard hydrogen electrode is 0.3 volts or more, and more preferably 0.3 to 1 volt.

Next, an eighth aspect of the present invention is characterized in that a phenol derivative in which the 4-position is unsubstituted and the 2, 3, 5, and 6-positions are substituted or unsubstituted is used as the polymerizable monomer. A method for coating a metal to be formed will be described.

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

As shown in FIG. 1, the electrolytic reaction is an anodic oxidation of a phenol derivative which is unsubstituted at position 4 and substituted or unsubstituted at positions 2, 3, 5, and 6. In particular,
Potassium hydroxide, sodium hydroxide, as supporting electrolyte
By using a basic compound such as calcium hydroxide or an alkali metal alcoholate, the phenol derivative is converted into a phenoxide ion, and the phenoxide ion undergoes oxidation to a phenoxy radical on the anode. The electrode potential of the working electrode in the electropolymerization reaction depends on the chemical structure, aqueous solution conditions, and the like of the phenol derivative whose 4-position is unsubstituted and whose 2, 3, 5, and 6-positions are substituted or unsubstituted. Things. At this time, the voltage applied between the electrodes is not particularly limited.

The reaction in which the electropolymerization reaction starts and grows into a polymer film is achieved by the coupling of the phenoxy radicals of the monomer or polymer and the increase of the number of polymerized units one by one as shown in FIG. . And
Since this polymer film is electrically insulating, the anode side, which is the working electrode, is inactivated due to its growth. Therefore, the amount of current in the electrolysis is reduced, and the growth stops soon.

Next, as the polymerizable monomer of the ninth invention, the 4-position is unsubstituted and one of the 2, 3, 5, 6-positions.
One or more substituents, and any of the substituents has 2 carbon atoms.
A metal coating method using a phenol derivative having at least one phenol derivative will be described.

A phenol derivative in which the 4-position is unsubstituted and one or more of the 2, 3, 5, and 6-positions are substituted and any of the substituents has two or more carbon atoms is used as a polymerizable monomer. When the polymerization is carried out, the resulting product swells with the electrolyte and exhibits an oil. Due to this swelling, even after the originally insulating polymerized product covers the electrode surface, the electrolytic solution reaches the vicinity of the electrode, and the electrolytic reaction continues for a long time without stopping. By removing the solution components from the swollen polymerization product, a polymer film having a thickness of about several tens of μm can be formed. Since the molecular structure of this polymer is linear with sterically bulky substituents in the side chains, a polymer film having excellent flexibility is obtained.

In the phenol derivative, the type of the substituent having two or more carbon atoms is not particularly limited. For example, a saturated alkyl group such as ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, vinyl group, allyl group, allenyl group,
In addition to an unsaturated alkyl group such as a propargyl group, a substituent such as an aromatic hydrocarbon group such as a phenyl group, an alkoxy group, a carbonylalkyl group, a carbonyloxyalkyl group, and an amide group can be used. In addition, 2 carbon atoms
There is also no particular limitation on the type of the substituent other than the substituent having at least one substituent.

The concentration of the phenol derivative in which the 4-position is unsubstituted and one or more of the 2, 3, 5, and 6 positions are substituted and any of the substituents has two or more carbon atoms has a concentration of 0.01 to
It is 10 mol / l, preferably 0.1 to 2 mol / l.

Next, a metal coating characterized by using 2-allylphenol, 2- (2-propenyl) phenol or 2-allyl-6-methylphenol as the polymerizable monomer according to the tenth aspect of the present invention. The method will be described.

2-allylphenol, 2- (2-propenyl) phenol and 2-allyl-6-methylphenol have a carbon-carbon unsaturated bond in the substituent.

The 4-position is unsubstituted, and one or more of the 2, 3, 5, and 6-positions are substituted.
The reaction formula of the phenol derivative having an unsaturated bond between carbon atoms in the electrolytic polymerization is shown in FIGS. 3, 4 and 5. FIG.
Shows a reaction in which the phenol derivative becomes phenoxide ion in an alkaline aqueous solution and generates a phenoxy radical by oxidation. FIG. 4 shows a reaction in which phenoxy radicals of a monomer or a polymer are coupled with each other and polymerization proceeds. There is no particular limitation on the applied voltage. FIG. 5 shows a radical crosslinking reaction of carbon-carbon unsaturated bonds contained in the substituents of the polymer obtained by the coupling. The radical crosslinking reaction proceeds by adding an initiator such as a peroxide, an azo compound, or a vulcanizing agent to the polymer product as necessary, and performing post-treatment such as heating or irradiation with ultraviolet light after completion of the electrolysis.

Thus, 2-allylphenol, 2- (2-
Propylene) phenol or 2-allyl-6-methylphenol is polymer-polymerized by a radical cross-linking reaction, if necessary, to achieve high strength without defects, and to improve electrical insulation. An excellent polymer film can be obtained.

Next, a metal coating method according to the eleventh aspect of the present invention, which is characterized in that pyrrole and its derivatives are used as the polymerizable monomer, will be described.

It is known that a conductive polymer film is formed on a working electrode by electrolytic oxidation of pyrrole and its derivatives. Since the product is conductive, the thickness of the polymer film can be easily 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.

When pyrrole and its derivatives are used as the polymerizable monomer, the electropolymerized polymer film has electrical conductivity. This is generally due to charge transfer by the dopant component contained in the coating. For this reason, it is also possible to insulate the coating on the metal conductor by desorbing the dopant from the polymer film formed on the metal conductor and reducing the electric conductivity of the polymer film. Examples of the method for removing the dopant include application of an electric field having a polarity different from that during electrolysis, contact with a solution of a compound having a reducing anion such as thiosulfate or hyposulfite as a component, and a combination of these methods. .

Next, a metal coating method according to the twelfth invention, wherein aniline and its derivative are used as the polymerizable monomer, will be described.

It is known that a conductive polymer film is formed on a working electrode by electrolytic oxidation of aniline and its derivatives. Since the product is conductive, the thickness of the polymer film can be easily 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.

When aniline and its derivatives are used as the polymerizable monomer, the electropolymerized polymer film has electric conductivity. This is due to the charge transfer by the dopant component contained in the film as described above. For this reason, by the same method as when using pyrrole and its derivatives, by removing the dopant from the polymer film, by lowering the electrical conductivity of the polymer film,
It is possible to insulate the coating formed on the metal conductor.

Next, a thirteenth embodiment of the present invention is characterized in that the metal conductor has an electrically insulating coating portion, and a coating is formed at a defective portion of the coating portion by the above-described coating method. A method for coating a metal will be described.

The metal conductor having an electrically insulating covering portion refers to an enameled wire whose surface is insulated and coated by so-called varnish coating, a metal conductor having an oxide film formed on the surface, and the like. If an insulating defect exists in these surface coating portions, the defective portion can be electrically connected to the outside, and this is used as an electrode. After performing the above-described electrolytic process or roughening process on the defective portion, the polymer is selectively contacted with an aqueous solution containing a polymerizable monomer and a voltage is applied to selectively form a polymer film on the defective portion, thereby forming an insulating coating. It can be performed.

By performing the electrolytic process or the roughening process,
Since an oxide layer and a surface treatment layer on the surface of the insulation defect, dirt, and the like are removed, a uniform electrolytic polymerized polymer film is efficiently formed. Further, the adhesion between the formed polymer film and the insulation defect is improved. Therefore, it is possible to more effectively perform selective insulation repair of electronic components such as insulated wires, transformer conductors, and capacitors having insulation defects.

Next, an insulating coated metal conductor according to a fourteenth aspect of the present invention, in which a coating is formed on a part or the entire surface of the metal conductor by the above-described coating method, will be described.

According to the above-described metal coating method, a polymer film having a film thickness ranging from submicron to several μm or tens of μm can be formed. Since the coating has no defect and has excellent adhesion to the metal conductor, it is possible to manufacture an insulating-coated metal conductor with higher productivity and reliability. For example, when the present invention is applied to an insulated wire, the thickness of the insulated wire can be reduced as compared with a conventional insulated 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.

FIG. 6 shows an example of a manufacturing process of the insulated metal conductor according to the present invention. The one-dimensional or two-dimensional metal conductor 1 is first introduced into the electrolytic cell 2, and electrolysis is performed in the electrolytic solution 3, and the surface is cleaned. The roughened metal conductor 8 is conveyed to the electrolytic polymerization tank 9 and electrolyzed in the electrolytic solution 10 to form a polymer film on the surface. After the polymer film is formed, if necessary, wash solution 1
4 and a heating process by the drying furnace 15 may be provided. Through the above steps, the metal conductor 16 having the polymer film on the surface is manufactured.

[0079]

EXAMPLE Next, a specific example will be described.

(Example 1) 5x60
x0.1mm strip-shaped copper plate and platinum plate, and silver-silver chloride standard electrode were immersed respectively, a voltage was applied so that the potential difference between the copper plate and the standard electrode was 1V, and electrolysis was performed for 1 minute. . After taking out the copper plate and platinum plate and washing them with water,
Immerse in an aqueous solution of dimethylphenol 0.5 mol, potassium hydroxide 0.5 mol, diethylamine 0.2 mol, water: methanol = 75: 25% by volume, and apply a DC voltage of 3 V between both electrodes using the copper plate as the anode. The electrolysis was performed for 5 minutes. After the electrolysis was completed, the copper plate was taken out, washed with water, and dried at 50 ° C. for 1 hour in a thermostat. A uniform polymer film is formed on the copper plate, and its thickness is 3
μm. A gold film was formed by vapor deposition on the polymer film, and the electrical insulation between the gold film and the portion of the copper electrode where the polymer film was not formed was measured to be 1.5 ×
It showed 1013 Ωcm, and no defect and peeling of the polymer film were confirmed.

(Example 2) 5 x 60
x0.02 mm strip-shaped copper foil, 5x60x0.1 mm platinum plate, and silver-silver chloride standard electrode were each immersed, and a voltage was applied so that the potential difference between the copper plate and the standard electrode was 1 V. The electrolysis was performed for minutes. After taking out the copper plate and the platinum plate and washing them with water, water of 0.7 mol concentration of 2-allylphenol, 0.7 mol concentration of potassium hydroxide, and 0.3 mol concentration of diethylamine:
Each was immersed in an aqueous solution of methanol = 75: 25% by volume, and a DC voltage of 3 V was applied between both electrodes using a copper foil as an anode to perform electrolysis for 1 minute. After the electrolysis was completed, the copper foil was taken out and washed with water, and then heated at 150 ° C. for 1 hour in a thermostat. A uniform polymer film was formed on the copper foil, and its thickness was 4 μm according to the gravimetric method. A gold film was formed on the polymer film by vapor deposition, and the electrical insulation between the gold film and the portion of the copper electrode where the polymer film was not formed was measured. No peeling was observed.

Example 3 A 5 × 60 × 0.02 mm strip-shaped copper foil and 5 × 60 × 0.02 mm strip-shaped copper foil were added to a 0.1 normal sodium hydroxide aqueous solution heated to 80 ° C.
A x60x0.1 mm platinum plate and a silver-silver chloride standard electrode were immersed, respectively, and a voltage was applied so that the potential difference between the copper plate and the standard electrode was 1 V, and electrolysis was performed for 2 minutes. The copper plate and the platinum plate are taken out, washed with water, immersed in an aqueous solution of water: methanol = 75: 25% by volume of 0.7 mol of 2-allylphenol, 0.7 mol of potassium hydroxide, and 0.3 mol of diethylamine, respectively. Was used as an anode, a DC voltage of 3 V was applied between both electrodes, and electrolysis was performed for 1 minute. After the electrolysis, remove the copper foil and wash it with water.
For 1 hour. A uniform polymer film was formed on the copper foil, and its thickness was 4 μm according to the gravimetric method. A gold film was formed on the polymer film by vapor deposition, and the electrical insulation between the gold film and the portion of the copper electrode where the polymer film was not formed showed 3.0 × 10 14 Ωcm,
No defects or peeling of the polymer film were observed.

Example 4 A 5 × 60 × 0.02 mm strip-shaped copper plate and a 5 × 60 × 0.1 m
m of a platinum plate and a silver-silver chloride standard electrode were immersed, and a voltage was applied so that the potential difference between the copper plate and the standard electrode was 1 V, and electrolysis was performed for 1 minute. After taking out the copper plate and the platinum plate and washing them with water, 2-allylphenol 0.7 molar concentration, potassium hydroxide 0.7 molar concentration, diethylamine
A 5x60x0.1mm strip-shaped platinum plate was immersed in an aqueous solution of 0.3 molar water: methanol = 75: 25% by volume, and a DC voltage of 3V was applied between both electrodes using a copper plate as an anode, and electrolysis was performed for 1 minute. Carried out. After the electrolysis was completed, the copper plate was taken out, washed with water, and then heated in a thermostat at 150 ° C. for 1 hour. A uniform polymer film is formed on the copper plate, and its thickness is determined by the gravimetric method.
It was 5 μm. A gold film was formed by vapor deposition on the polymer film, and the electrical insulation between the portion of the copper electrode where the polymer film was not formed and the gold film was measured.
It showed 10 14 Ωcm, and no defects and peeling of the polymer film were confirmed.

(Example 5) 5x60
x0.1mm strip-shaped copper plate and platinum plate, and silver-silver chloride standard electrode were immersed respectively, a voltage was applied so that the potential difference between the copper plate and the standard electrode was 1V, and electrolysis was performed for 1 minute. . After taking out the copper plate and platinum plate and washing them with water, water: methanol = 75: 25% by volume of pyrrole 0.1 mol, potassium hydroxide 0.1 mol, diethylamine 0.3 mol
, And a voltage was applied so that the potential difference between the copper plate and the standard electrode was 1.5 V, and electrolysis was performed for 5 minutes. After the electrolysis was completed, the copper plate was taken out, washed with water, and dried at 50 ° C. for 1 hour in a thermostat. A uniform polymer film is formed on the copper plate, and its film thickness is 1.5
μm. A tape peeling test was performed on this polymer film, but no peeling of the polymer film was confirmed.

(Example 6) 5x60
x0.1mm strip-shaped copper plate and platinum plate, and silver-silver chloride standard electrode were immersed respectively, a voltage was applied so that the potential difference between the copper plate and the standard electrode was 1V, and electrolysis was performed for 1 minute. . After taking out the copper plate and the platinum plate and washing them with water, water: methanol = 75: 25% by volume of aniline 0.1 mol, potassium hydroxide 0.1 mol, diethylamine 0.3 mol
Each was immersed in an aqueous solution of the above, and a DC voltage of 3 V was applied between both electrodes using the copper electrode as an anode, and electrolysis was performed for 5 minutes.
After the electrolysis was completed, the copper plate was taken out, washed with water, and dried at 50 ° C. for 1 hour in a thermostat. A uniform polymer film was formed on the copper plate, and its thickness was 2 μm according to the gravimetric method.
A tape peel test was performed on this polymer film,
No peeling of the polymer film was observed.

Example 7 An enamel-coated lead wire having a diameter of 1 mm was wound into a loop having a diameter of 2 cm, and a part of the enamel coating was removed with sandpaper to prepare an electrode having an insulating defect portion formed thereon. In a 0.01 standard sulfuric acid aqueous solution,
A strip-shaped platinum plate of x60 × 0.1 mm and a silver-silver chloride standard electrode were respectively immersed, a voltage was applied so that a potential difference between the electrode and the standard electrode was 1 V, and electrolysis was performed for 1 minute. After taking out the electrode and the platinum plate and washing with water,
2-allylphenol 0.7 mol concentration, potassium hydroxide 0.7 mol concentration, diethylamine 0.3 mol concentration water: methanol = 75:25 volume% aqueous solution, respectively, 3V direct current voltage is applied between both electrodes, 5 The electrolysis was performed for minutes. After the electrolysis was completed, the electrode was taken out, washed with water, and heated at 150 ° C. in a constant temperature bath. As a result, a polymer film was selectively formed on the portion of the electrode where the enamel coating was removed. The electrode and the platinum plate were immersed in a 0.1 molar aqueous solution of lithium perchlorate, and the conduction between the two electrodes was examined. As a result, the insulation was good.

(Example 8) A fan motor for vehicle electrical equipment having a poorly insulated portion in a winding portion using an enamel-coated conductor was used as an electrode. The motor, a 5 × 60 × 0.1 mm strip-shaped platinum plate, and a silver-silver chloride standard electrode were each immersed in a 0.01 standard sulfuric acid aqueous solution, and a voltage was applied so that the potential difference between the motor and the standard electrode was 1 V. The electrolysis was performed for 1 minute. The motor and the platinum plate were taken out, washed with water, immersed in an aqueous solution of 0.7 mol of 2-allylphenol, 0.7 mol of potassium hydroxide, and 0.3 mol of diethylamine in water: methanol = 75: 25% by volume, respectively. A DC voltage of 3 V was applied between the electrodes, and electrolysis was performed for 10 minutes. After electrolysis, take out the motor and wash it with water,
As a result of heating at 150 ° C. in a thermostat, an insulating film was selectively formed on the insulation defect existing in the winding of the motor. The motor and the platinum plate were immersed in a 0.1 molar aqueous solution of lithium perchlorate, and the conduction between the two electrodes was examined.

(Example 9) A polymer film was continuously formed on a copper wire having a diameter of 0.1 mm by using a polymer film forming apparatus by electrolytic polymerization as shown in FIG. For anodizing electrolyte
A 0.01 standard sulfuric acid aqueous solution is used in the electrolytic solution for electropolymerization, and water: methanol = 75: 25% by volume is 0.7 mol of 2-allylphenol, 0.7 mol of potassium hydroxide, 0.1 mol of hydroxyethyl methacrylate, and 0.2 mol of diethylamine. Were used in each case. In the anodizing bath, a voltage was applied so that the potential of the copper wire electrode was 1 V with respect to the silver-silver chloride standard electrode. In the electrolytic polymerization polymer forming tank, a DC voltage of 3 V was applied between the copper wire electrode and the counter electrode. Electrolysis was carried out under the conditions that the 10 m anodizing tank and the polymer forming tank were run at a linear velocity of 0.2 m / sec. The coil was formed using the copper wire coated with the insulation in this way, but the film strength was sufficient and the insulation was good.

(Comparative Example 1) 2,6-dimethylphenol 0.5
A 5 × 60 × 0.1 mm strip-shaped copper plate and a platinum plate were immersed in an aqueous solution of molarity, potassium hydroxide 0.5 molarity, diethylamine 0.2 molarity in water: methanol = 75: 25% by volume, and the copper plate was used as an anode. A DC voltage of 3 V was applied between the electrodes, and electrolysis was performed for 5 minutes. After the electrolysis was completed, the copper plate was taken out, washed with water, and dried at 50 ° C. for 1 hour in a thermostat.
An oil-drop-like product was observed on the copper plate, and a uniform polymer film was not formed.

Comparative Example 2 0.7 mol of 2-allylphenol, 0.7 mol of potassium hydroxide, 0.3 mol of diethylamine
A 5x60x0.02mm strip-shaped copper foil and a 5x60x0.1mm platinum plate are immersed in an aqueous solution of molarity water: methanol = 75: 25% by volume, and 3V DC is applied between both electrodes using the copper foil as the anode. A voltage was applied and electrolysis was performed for 1 minute. After electrolysis,
The copper foil was taken out, washed with water, and heated in a thermostat at 150 ° C. for 1 hour. The polymer film was formed only on a part of the copper foil, and on other parts, only oil-drop-like products were confirmed.

(Comparative Example 3) A water solution of 0.1 mol of pyrrole, 0.1 mol of potassium hydroxide and 0.3 mol of diethylamine in a 75: 25% by volume aqueous solution of methanol: 5 × 60 × 0.1
mm strip copper plate, platinum plate, and silver-silver chloride standard electrode are immersed, respectively, and the potential difference between the copper plate and the standard electrode is reduced.
A voltage was applied to 1.5 V, and electrolysis was performed for 5 minutes. After electrolysis, remove the copper plate and wash it with water.
After drying at ℃ for 1 hour, the formed polymer film was peeled off from the copper plate.

[0092]

As described above, according to the present invention, it is possible to form a coating having no defects and excellent adhesion to a metal conductor on a metal.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an oxidation reaction of electrolytic polymerization according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a growth reaction in electrolytic polymerization according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating an oxidation reaction of electrolytic polymerization in a second embodiment of the present invention.

FIG. 4 is a diagram for explaining a growth reaction in electrolytic polymerization according to a second embodiment of the present invention.

FIG. 5 is a view for explaining a crosslinking reaction of a polymer film in a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a polymer film forming apparatus used in a metal coating method according to an eighth embodiment of the present invention.

[Description of Signs] 1 Untreated metal conductor 2 Anodizing bath 3 Anodizing electrolytic solution 4 Anodizing power supply 5 Opposing electrode for anodizing 6 Cleaning bath 7 Cleaning solution 8 Surface roughened metal foil 9 Electropolymerized polymer forming bath 10 Electrolytic solution for electrolytic polymerization 11 Power supply for electrolytic polymerization 12 Counter electrode for electrolytic polymerization 13 Cleaning tank 14 Cleaning liquid 15 Drying furnace 16 Drum for winding metal conductor with polymer film formed metal

Claims (14)

[Claims] A step of contacting the metal conductor as an electrode with an electrolytic solution, applying a voltage so that the metal conductor acts as an anode, and oxidizing and dissolving the surface of the metal conductor; A polymer film is formed on the surface of the metal conductor by contacting the metal conductor with an aqueous solution containing a polymerizable monomer, a supporting electrolyte and an alkylamine, and using the metal conductor as an electrode to perform electrolytic polymerization of the polymerizable monomer. A method for coating a metal, comprising the steps of: 2. A metal conductor is brought into contact with an electrolytic solution as an electrode, a voltage is applied so that the metal conductor acts as an anode, and the metal conductor is oxidized and dissolved to roughen the surface of the metal conductor. And contacting the metal conductor subjected to the surface roughening with an aqueous solution containing a polymerizable monomer, a supporting electrolyte and an alkylamine, and performing the electrolytic polymerization of the polymerizable monomer using the metal conductor as an electrode. Forming a polymer film on the surface of the metal conductor. 3. The metal coating method according to claim 1, wherein a solution containing sulfuric acid or hydrochloric acid is used as an electrolytic solution in the oxidative dissolution step. 4. The metal coating method according to claim 1, wherein a solution containing sodium hydroxide or potassium hydroxide is used as an electrolytic solution in the oxidative dissolution step. 5. The metal coating method according to claim 1, wherein a solution containing ammonia or an alkylamine is used as the electrolytic solution in the oxidative dissolution step. 6. The metal coating method according to claim 1, wherein a voltage of the metal conductor with respect to a standard electrode is kept constant as a method of applying the voltage. . 7. The metal coating method according to claim 1, wherein the metal conductor has copper as a composition. 8. The method according to claim 1, wherein the polymerizable monomer is a phenol derivative which is unsubstituted at the 4-position and substituted or unsubstituted at the 2-, 3-, 5- and 6-positions. 8. The method for coating a metal according to any one of 3, 4, 5, 6 and 7. 9. The polymerizable monomer is unsubstituted at the 4-position and substituted at one or more of the 2, 3, 5, and 6-positions, and any of the substituents has two or more carbon atoms. A phenol derivative is used, wherein the phenol derivative is used.
8. The method for coating a metal according to any one of 3, 4, 5, 6 and 7. 10. The method according to claim 10, wherein the 4-position is unsubstituted, and
As a phenol derivative in which at least one of positions 5 and 6 is substituted and any of the substituents has two or more carbon atoms, 2-allylphenol, 2- (2-propenyl) phenol or 2-allyl-6 The metal coating method according to any one of claims 1, 2, 3, 4, 5, 6, 7, and 9, wherein -methylphenol is used. 11. The method according to claim 1, wherein pyrrole or a derivative thereof is used as the polymerizable monomer.
8. The method for coating a metal according to any one of 2, 3, 4, 5, 6, and 7. 12. The method according to claim 1, wherein aniline or a derivative thereof is used as the polymerizable monomer.
8. The method for coating a metal according to any one of 2, 3, 4, 5, 6, and 7. 13. The method according to claim 1, wherein the metal conductor has an electrically insulating covering portion, and the defective portion of the covering portion has
2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 1
3. A method for coating a metal, comprising forming the coating by the coating method according to any one of the above items 2. 14. A part or all of a metal conductor surface,
Claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1
13. An insulated metal conductor, wherein a coating is formed by the coating method according to any one of 1 and 12.