JP2002047596A - Surface-treatment method for aluminum or alloy thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-treatment method for aluminum or the alloy thereof by which antibacterial properties, thermal conductivity or the like can be imparted to base materials by simple surface treatment. SOLUTION: Base material 12 and 14 formed of aluminum or the alloy thereof are subjected to electrolytic treatment in an electrolytic solution in which one or two of silver nitrate and copper nitrate are added as the nitrate of metal to a sulfuric acid bath, an oxalic acid bath or their mixed bath in such a manner that the electric current of PR of flowing negative waves or of pulse waves of flowing negative wave is applied under the superimposition of alternate and direct current. By this treatment, oxidized films are formed on the surfaces of the base materials 12 and 14, and simultaneously, the added metal of nitrate can be precipitated into the oxidized films.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a surface treatment method for treating a surface of aluminum or an alloy thereof.

[0002]

2. Description of the Related Art As a surface treatment method for aluminum or its alloy, one disclosed in Japanese Patent Publication No. 5-14033 is known. According to this known surface treatment method, a surface of a base material formed of aluminum or an alloy thereof is subjected to anodization treatment to form an anodized film, and then a mother material having an anodized film in an electrolytic solution containing a metal salt. This is a method of depositing a metal in an anodic oxide film by applying an AC voltage to a material, and is mainly intended to bring a surface color of a base material to a required color tone.

Further, as a surface treatment method for aluminum or its alloy, a method disclosed in Japanese Patent Application Laid-Open No. 9-71897 is known. Such a known surface treatment forms an anodized film by performing anodizing on the surface of a base material formed of aluminum or an alloy thereof, and then forms the anodized film in a dispersion containing semiconductor fine particles having a photocatalytic action. This is a method in which semiconductor particles are filled by electrophoresis into the pores of the anodic oxide film of the base material immersed in the base material thus immersed, and mainly to impart antibacterial properties, antifouling properties, etc. to the base material. The purpose is. This surface treatment method further discloses that, in addition to the semiconductor fine particles, an antibacterial metal such as silver or copper is deposited on the surface of the anodic oxide coating. Is increasing.

[0004]

However, in such a known surface treatment method, an anodic oxide film is first formed on the surface of a base material, and then a metal is deposited by electrolytic treatment (or by electrophoresis). Semiconductor particles). Therefore, two or three treatment steps are required to perform the required surface treatment on the base material, and due to this, the time required for the surface treatment is increased,
There is a problem that the equipment for surface treatment is also large and complicated, and the cost for performing the surface treatment is also increased.

[0005] Further, a base material formed of aluminum or an alloy thereof, such as an inner pot of a rice cooker or a hot plate, is provided with a fluororesin coating on the surface thereof. When the fluororesin coating is formed in this manner, the heat conductivity of the cooking utensils is not high because the thermal conductivity of the fluororesin coating is relatively small, and it is desired to improve the heating efficiency (cooking heating efficiency). Further, such a base material is desired to have antibacterial properties from the viewpoint of safety and health.

An object of the present invention is to provide a surface treatment method for aluminum or an alloy thereof, which can impart antibacterial property, deodorization property, heat conductivity, conductivity and the like to a base material by a simple surface treatment. is there. Another object of the present invention is to provide a surface treatment of aluminum or its alloy which can impart antibacterial, deodorant, thermal conductivity, conductivity, etc. to a base material having a particulate resin coating with a simple surface treatment. Is to provide a way.

[0007]

According to the present invention, a base material formed of aluminum or an alloy thereof is treated in a sulfuric acid bath, an oxalic acid bath or a mixed bath thereof as one of silver nitrate and copper nitrate as a metal nitrate. PR in which an alternating superimposition and a minus wave are flown in an electrolytic solution to which one or two of silver sulfate and copper sulfate as metal sulfates are added.
Alternatively, an electrolytic treatment is performed by applying a pulse wave current flowing a minus wave, thereby forming an anodic oxide film on the surface of the base material and simultaneously depositing the added nitrate or sulfate metal on the anodic oxide film. This is a method for surface treatment of aluminum or an alloy thereof.

According to the present invention, one or two of silver nitrate and copper nitrate as nitrates, or silver sulfate and sulfuric acid as sulfates in a sulfuric acid bath, an oxalic acid bath or a mixed bath thereof as an electrolytic solution. Using one or two of copper is added, and the electrolytic treatment is performed by applying an alternating current and direct current in the electrolytic solution and applying a current of a PR or a pulse wave of a negative wave. At the same time as forming an anodized film on the surface of the base material formed from
The nitrate or sulfate metal added to the anodic oxide film can be deposited, and the formation of the anodic oxide film and the deposition of the metal can be performed by a single electrolytic treatment. For example, silver nitrate (or silver sulfate) as nitrate (or sulfate)
And silver nitrate and copper nitrate (or silver sulfate and copper sulfate) as nitrate (or sulfate), silver when copper is used, copper nitrate (or copper sulfate) as nitrate (or sulfate). ) Can be used to precipitate silver and copper. By performing such a surface treatment, the electrolytic treatment process can be simplified and shortened, and the cost required for the surface treatment of the base material can be reduced.

In the base material subjected to such a surface treatment, silver (or copper, silver and copper) is precipitated in the pores of the anodic oxide film formed on the surface of the base material, so that the antibacterial property, Deodorant,
Thermal conductivity and conductivity are enhanced, and coloring can be performed. When a hard film is formed as the anodic oxide film, the base material can have sufficient wear resistance and high hardness. Such base materials include architectural members or members for transportation or transportation equipment.

[0010] Further, the present invention provides a method of forming a base material having at least a part thereof on a surface of a base material formed of aluminum or an alloy thereof. Electrolysis in which one or two of silver nitrate and copper nitrate as a metal nitrate, or one or two of silver sulfate and copper sulfate as a metal sulfate are added to an acid bath or a mixed bath thereof. In the liquid, AC / DC superposition, a current of a PR for flowing a negative wave or a pulse wave for flowing a negative wave is applied for electrolytic treatment, thereby forming an anodic oxide film on the surface of the base material, and simultaneously adding nitrate or sulfuric acid. A surface treatment method for aluminum or an alloy thereof, comprising depositing a salt metal on the anodic oxide film.

According to the present invention, first, a particulate resin film is formed on at least a part of a base material formed from aluminum or an alloy thereof, that is, a part or the whole thereof, and thereafter, a particulate resin film is formed. The base material is electrolytically treated. Either one or two of silver nitrate and copper nitrate as a nitrate, or any one of silver sulfate and copper sulfate as a sulfate in a sulfuric acid bath, an oxalic acid bath or a mixed bath thereof as an electrolytic solution for the electrolytic treatment. Alternatively, an electrolytic treatment is performed by using a mixture obtained by adding the two, and applying a current of PR in which an alternating current is superimposed and a negative wave or a pulse wave in which a negative wave is applied to the electrolytic solution. By performing the electrolytic treatment in this manner, the electrolytic solution acts on the surface of the base material through the fine voids of the particulate resin film, and can form an anodic oxide film on the surface of the base material, and the added nitrate or sulfuric acid. The metal salt can be deposited. For example, silver when silver nitrate (or silver sulfate) is used, copper when copper nitrate (or copper sulfate) is used, and silver when silver nitrate and copper nitrate (or silver sulfate and copper sulfate) are used. And copper can be deposited.

In the base material subjected to such surface treatment, silver (or copper, silver and copper) is precipitated on the anodic oxide film formed on the surface of the base material, so that the base material has antibacterial properties and deodorization. Properties, thermal conductivity, and conductivity are enhanced. Further, in the present invention, a fluororesin film as the particulate resin film is formed on one surface of the base material, and the base material is subjected to an electrolytic treatment in the electrolytic solution, whereby the base material is passed through the fluororesin film. At the same time as forming the anodic oxide film on one side, the metal of nitrate or sulfate added to the anodic oxide film is deposited, and at the same time as forming the anodic oxide film on the other surface of the base material, Characterized in that a metal of a nitrate or a sulfate is deposited.

According to the present invention, a fluororesin film is formed on one surface of the base material, and the above-described electrolytic processing is performed on the base material on which the fluororesin film is formed. When the electrolytic processing is performed in this manner, the electrolytic solution acts on the base material through the fluorine film on one side of the base material, and an anodic oxide film can be formed on one side of the base material. Nitrate or sulfate metals can be deposited. Further, on the other surface of the base material, a metal of nitrate or sulfate can be deposited on the formed anodic oxide film at the same time as forming an anodic oxide film on the surface. At this time, since silver (or copper, silver and copper) precipitates, antibacterial properties, deodorizing properties, thermal conductivity, and conductivity on both sides of the base material can be enhanced. Examples of such a base material include a pot (for example, a cooking pot, a frying pan or the like) having a fluororesin coating on one side, a pot (an inner pot of a rice cooker or the like), a hot plate, and the like.

Further, the present invention provides a base material formed of aluminum or an alloy thereof, wherein the base material has a particulate resin film formed on at least a part of the surface thereof. Immersion in a bath or a mixed bath thereof to perform anodic oxidation treatment to form an anodic oxide film on the surface of the base material, and then use one or two of silver nitrate and copper nitrate as metal nitrate, or metal Electrolytic treatment in an electrolytic solution to which one or two of silver sulfate and copper sulfate are added as sulfates, thereby precipitating the metal of nitrate or sulfate added to the anodic oxide film. This is a method for surface treatment of aluminum or an alloy thereof.

According to the present invention, a particulate resin coating is formed on at least a part of the surface of a base material formed from aluminum or an alloy thereof, that is, a part or the whole thereof, and then a particulate resin coating is formed. The base material is immersed in a sulfuric acid bath, an oxalic acid bath, or a mixed bath thereof to perform anodizing treatment. At this time,
The treatment liquid in the bath acts on the surface of the base material through the voids of the particulate resin film, whereby an anodic oxide film can be formed on the surface of the base material having the particulate resin film. Thereafter, electrolytic treatment is performed using an electrolytic solution to which one or two of silver nitrate and copper nitrate as nitrates or one or two of silver sulfate and copper sulfate as sulfates is added. At this time, the electrolytic solution acts on the anodic oxide film on the surface of the base material through the particulate resin film, thereby allowing nitrate or sulfate metal to be deposited on the anodic oxide film formed thereby. As described above, even if a predetermined electrolytic treatment is performed after a general anodic oxidation treatment, an anodized film is formed on a base material having a particulate resin film, and a predetermined metal is deposited on the anodized film. can do. At the time of electrolytic treatment, AC, which is a commercial power source, AC / DC superposition,
The electrolytic treatment can be performed by applying a current such as a PR for flowing a negative wave or a pulse wave for flowing a negative wave.

In the base material subjected to such a surface treatment, silver (or copper, silver and copper) is precipitated on the anodic oxide film formed on the surface of the base material, so that the base material has antibacterial properties and deodorization. Properties, thermal conductivity, and conductivity are enhanced. Further, the present invention is characterized in that an added nitrate or sulfate metal is deposited on the anodized film and the particulate resin film by subjecting the base material to an electrolytic treatment. According to the present invention,
In addition to the anodized film of the base material, nitrate or sulfate metal is also deposited on the particulate resin film covering the surface of the base material. , Deodorization, thermal conductivity, and conductivity can be further enhanced.

Further, the present invention is characterized in that the particulate resin coating is a fluororesin coating, a phenolic resin coating or an acrylic resin coating. In the present invention, since the coating formed on the surface of the base material is a fluororesin coating, a phenolic resin coating or an acrylic resin coating, the electrolytic solution for performing the electrolytic treatment (or the treating solution for performing the anodic oxidation treatment in addition to these) is used. By acting on the surface of the base material through the voids present in the resin film, an anodic oxide film is formed on the surface of the base material, and a predetermined metal can be deposited on the anodic oxide film.

Further, in the present invention, the base material is a pot, a pot,
It is characterized by being a hot plate, tableware, kettle or foil. According to the present invention, since the anodic oxide film is formed on the surface of the aluminum or aluminum alloy base material and silver (or copper, silver and copper) is deposited on the anodic oxide film, antibacterial properties and deodorizing properties are obtained. It can be applied to pots, pots, hot plates, tableware, kettles, and foils for wrapping foods with good heat conductivity and conductivity. In addition to this, the heating efficiency when performing the heating cooking can be improved.

Further, a particulate resin film, for example, a fluororesin film is formed on the surface of the aluminum or aluminum alloy base material, and silver (or copper, silver, and silver) is formed on the anodic oxide film on the surface of the base material through the particulate resin film. Copper) is deposited,
Antibacterial, deodorizing, heat conductive, and conductive properties are improved despite the application of a particulate resin coating, for example, a fluororesin coating, making it suitable for pots (cooking pots, etc.) and pots (cooking pots, etc.) It can be conveniently applied, and by applying to them, the safety of foods and cooked products can be improved, and the heating efficiency when heating and cooking can be improved.

Further, in the present invention, the base material is a building member or a member for transportation or transportation equipment. According to the present invention, since the anodic oxide film is formed on the surface of the base material (particularly, a hard material is formed), the wear resistance and hardness of the base material can be sufficiently increased. Since the metal of nitrate or sulfate is deposited on the oxide film, the thermal conductivity of the anodic oxide film, in other words, the heat radiation property, can be increased. It can be advantageously applied, and by applying such a material, the fire resistance, wear resistance, and hardness of this member can be increased.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a method for surface treating aluminum or an alloy thereof according to the present invention will be described with reference to the accompanying drawings. First, with reference to FIG. 1 and FIG. 2, an embodiment of a surface treatment method for aluminum or an alloy thereof according to the present invention will be described. FIG. 1 is a simplified diagram schematically illustrating an example of a processing apparatus for performing an embodiment of a surface treatment method according to the present invention. FIG. 2 is a diagram illustrating a part of a base material processed by the processing apparatus of FIG. FIG. 4 is a partially enlarged cross-sectional view that is enlarged and simplified.

In FIG. 1, the illustrated processing apparatus includes a rectangular parallelepiped electrolytic cell 2, and electrodes 4 and 6 are arranged on both sides of the electrolytic cell 2. In this embodiment, the electrodes 4, 6
Is composed of four plate-shaped electrodes 8, 10 arranged at intervals in the longitudinal direction, that is, in the left-right direction in FIG.
These plate-shaped electrodes 8, 10 are formed of carbon. The electrodes 4 and 6 are electrically arranged in parallel, the four plate-like electrodes 8 of one electrode 4 are electrically connected in series, and the four plate-like electrodes 10 of the other electrode 6 are electrically connected. They are connected in series.

Base materials 12, 14 to be surface-treated are arranged between the pair of electrodes 4, 6. One base material 12 is disposed inside the electrode 4 so as to face the electrode 4, and the other base material 14 is
And is disposed inside thereof in opposition to. The base materials 12, 14
For example, the base material 12 is formed of a plate-shaped member.
14 is formed from aluminum or an aluminum alloy. This processing apparatus performs a surface treatment on base materials 12 and 14 formed of aluminum or an alloy thereof as described later.

The electrolytic cell 2 is filled with an electrolytic solution for surface treatment, and the base materials 12 and 14 to be treated are immersed in the electrolytic solution. As the electrolytic solution, a sulfuric acid bath, an oxalic acid bath, or a mixed bath thereof is used. Then, one or two of silver nitrate and copper nitrate, that is, silver nitrate, copper nitrate, or both are added to such a bath as a metal nitrate. When a sulfuric acid bath is used, the sulfuric acid is, for example, 150
In the case where an oxalic acid bath is used, for example, it is dissolved at a rate of 20 to 40 g / liter. In addition, silver nitrate or copper nitrate added to such a bath is added, for example, at a rate of 2 to 10 g / liter. When the amount of metal nitrate is less than 2 g / l, the amount of precipitated metal during the surface treatment is reduced. When the amount of metal nitrate exceeds 10 g / l, pits are formed on the anodic oxide film during the surface treatment. (Pitting corrosion) occurs and coating defects easily occur.

Instead of nitrate, one or two of silver sulfate and copper sulfate as metal sulfates, ie, silver sulfate,
Copper sulfate or both of them may be added. In this case, the added silver sulfate or copper sulfate is, for example, 2%.
It is added at a rate of 〜１０10 g / liter. Base material 12,1
When surface treatment is applied to the base material 4, a current having an alternating superimposed waveform, that is, a current obtained by superimposing an alternating current and a DC positive current is applied to the base materials 12 and 14, and the base material 1 is added by adding such a current.
2 and 14 are subjected to electrolytic treatment. In this embodiment, the DC power supply 1
The positive side of the DC power supply 6 is electrically connected to the reactor 18, and the negative side of the DC power supply 16 is electrically connected to the electrodes 4, 6 (plate-shaped electrodes 8, 10). Further, an AC power supply 20 is electrically connected to the reactor 18 and the reactor 1
8 superimposes the current on the positive side of the DC power supply 16 on the AC current from the AC power supply 20 and supplies the superimposed current to the base materials 12 and 14 to be processed.

At the time of surface treatment, the current density is, for example, 1 to 1
The current density is selected so as to be in the range of 0 A / dm ² , and the current is continuously supplied for a predetermined time. Current density is 10
If it exceeds A / dm ² , discoloration such as burns is likely to occur in the anodic oxide film formed by the surface treatment.
Damage due to electric discharge is likely to occur in the contact portions between the jigs 2 and 14 and the jig holding the jigs. On the other hand, when the current density is 1 A / dm ²
When it is smaller, the current flowing in the electrolyte is small, and the treatment efficiency of the surface treatment is deteriorated.

At the time of this surface treatment, the temperature of the electrolytic solution bath is selected, for example, so as to fall within a range of -10 to 25 ° C. When the temperature of the bath exceeds 25 ° C., the anodic oxide film formed on the surfaces of the base materials 12 and 14 becomes soft, and in some cases, a flat film cannot be obtained. On the other hand, when the temperature of the bath is lower than −10 ° C., the processing efficiency of the surface treatment is deteriorated, and the processing cost is increased. With the processing apparatus described above, the base material 12, 1
When the surface treatment is applied to 4, the surfaces of the base materials 12, 14 are formed as shown in FIG. Referring to FIG. 2, anodized film 22 (so-called alumite film) is formed on surfaces of base materials 12 and 14 formed of aluminum or an alloy thereof.
This anodic oxide film 22 is composed of a barrier layer 24 formed on the surface of the base material 12 (14) and a porous layer 26 formed on the surface of the barrier layer 24. The thickness of the barrier layer 24 is About 0.01 to 0.1 μm, and the porous layer 2
6 has a thickness of about 10 to 200 μm.

When the surface is treated by the above-described surface treatment method, when a metal of a nitrate, for example, silver nitrate (or silver sulfate) is used in a large number of holes 28 in the porous layer 26, silver or copper nitrate (or copper sulfate) is used. When used, copper, and when silver nitrate and copper nitrate (or silver sulfate and copper sulfate) are used, silver and copper precipitate, and a deposited metal 30 is formed at the bottom of the hole 28. Accordingly, since metal, in this embodiment, silver and / or copper is deposited in the holes 28 of the porous layer 26, the base material 12 (1
4) Antibacterial properties and antifouling properties are imparted, hygiene safety is maintained, and the thermal conductivity and conductivity of the anodic oxide film 22 on the surface are enhanced, thereby improving heat dissipation and reducing static electricity. The effect of prevention is obtained. In addition, since the anodic oxide film 22 is formed on the surface of the base material, the hardness of the surface of the base material 12 (14) is increased, the wear resistance is improved, and particularly, the hard anodic oxide film 22 is formed. By doing so, sufficient wear resistance and high hardness can be provided.

Such processing is performed by using various products made of aluminum or an alloy thereof as the base materials 12 and 14, such as tableware (tea bowls, plates, cups, etc.) and aluminum foil tableware (various containers,
Plates), aluminum foil for cooking, pots (cooking pans, frying pans, etc.), kettles, etc., and by applying to them, heating efficiency during cooking can be improved, Food safety can also be ensured.

Further, since such surface treatment increases the hardness of the anodic oxide film 22 and also improves the heat conductivity (in other words, the heat dissipation), it can be used for members other than the field of cooking appliances, for example. It can be conveniently applied to architectural members (aluminum sash members, doors, wall members, etc.) and traffic or transportation equipment members (automobiles, aircraft, ships, etc.). ,
Fire resistance and abrasion resistance can be improved.

In the above-described embodiment, the electrolytic treatment is performed by applying a current having an alternating superimposed waveform during the surface treatment.
In place of the current of the superimposed AC / DC, a current of a PR that causes a negative wave or a current of a pulse wave that causes a negative wave to be added may be used.
As described above, the predetermined surface treatment can be performed by one electrolytic treatment. The anodic oxide film 22 is formed on the surfaces of the base materials 12 and 14, and a metal is applied to the formed anodic oxide film 22. Can be deposited.

In the above-described example, the present invention has been described as applied to the formation of the anodic oxide film 22 on the base materials 12 and 14 formed of aluminum or an alloy thereof, but is not limited thereto.
In addition to forming an anodic oxide coating on a base material having a particulate resin coating, for example, a fluororesin coating, on the surface of a base material made of aluminum or an alloy thereof, it is also possible to deposit silver and / or copper on the formed anodic oxide coating. Can be applied. The surface treatment is performed in the same manner as described above using the processing apparatus described above, that is, the base material having the fluororesin coating as the particulate resin coating is immersed in the above-described electrolytic solution, and the same as described above in this immersion state Is applied, a base material having a particulate coating is formed as shown in FIG. That is, the base material 3
An anodic oxide film 34 is formed on the surface of the substrate 2, and the anodic oxide film 34 is composed of a barrier layer 36 on the surface of the base material 32 and a porous layer 38 on the surface of the barrier layer 36. in this case,
Since the fluororesin coating 40 exists on the surface of the base material 32,
The amount of electrolyte acting on the surface of the base material 32 is small, and the base material 3
The thickness of the anodic oxide film 34 formed on the surface of
For example, the thickness is about 2 to 4 μm, and the coating of 2 to 4 μm includes the barrier layer 36 and the porous layer 38. In addition, when such treatment is performed, when a metal of nitrate (or sulfate) such as silver nitrate (or silver sulfate) is used in a large number of holes 42 in the porous layer 38 on the surface side of the anodic oxide film 34, silver When copper nitrate (or copper sulfate) is used, copper, silver nitrate, and copper nitrate (or silver sulfate and copper sulfate) are used, silver and copper precipitate in the holes 42, and in addition, a fluororesin coating is formed. 40, and the deposition proceeds from the anodic oxide film 34 toward the surface of the fluororesin film 40. At this time, as shown in FIG. 3, the fluororesin coating 40 is a collection of fine spherical particles, and there are voids communicating with each other inside the resin coating 40. The liquid acts on the surface of the base material 32 through these voids. In connection with this, the thickness of the anodic oxide film 34 formed on the surface of the base material 32 is reduced, and the metal in the electrolytic solution passes through the voids of the fluororesin film 40 to form the porous layer of the anodic oxide film 34. 38, and also precipitates in the voids of the fluororesin coating 40. Since the anodic oxide film 34 is formed on the surface of the base material 32 even with the fluororesin film 40 as described above, the hardness of the surface of the base material 32 can be increased to provide wear resistance. Since a metal of nitrate or sulfate, ie, silver and / or copper, is deposited on the generated anodized film 34 and the fluororesin film 40, the thermal conductivity and conductivity of the base material 32 and the fluororesin film 40 on the surface thereof are increased. , Thereby improving the heat dissipation and preventing static electricity. In addition, antibacterial properties of the base materials 12, 14 and the fluororesin coating 40,
Antifouling properties can be imparted and sanitary safety can be maintained.

Such treatment is performed by various products made of aluminum or an alloy thereof having the fluororesin coating 40, such as a pot (cooking pot, frying pan, etc.), a pot (an inner pot of a rice cooker, etc.),
It can be conveniently applied to a hot plate or the like, and by applying to them, it is possible to improve the heating efficiency at the time of cooking and to ensure food safety. Inner pot (or pot) of rice cooker as base material
In this case, the inner pot body (or the pot body) is made of aluminum, and its inner surface is coated with a fluororesin. When the above-described surface treatment is performed on such a rice cooker (or pan), on the inner surface side of the rice cooker (or pan),
The electrolytic solution acts on the inner pot body through the gap of the fluororesin coating on the surface side, and a thin anodic oxide film is formed on the inner surface of the inner pot body (or the pot main body), and nitrate or sulfate in the electrolytic solution is formed. Metal deposits on the anodized film and the fluororesin film on the surface. In addition, on the outer surface side of the rice cooker inner pot (or pot), as understood from the above description, the electrolyte directly acts on the inner pot main body, and the outer surface of the inner pot main body (or pot main body). A relatively thick anodic oxide film is formed on
Nitrate or sulfate metal is deposited on the anodized film. Therefore, the thermal conductivity of the rice cooker itself (or the pot itself) is enhanced, thereby improving the heating efficiency and enabling efficient rice cooking (or cooking).

In the embodiment described above, the present invention is applied to the case where the fluororesin coating 40 is provided on the surface of the base material 32. However, the present invention is not limited to this, and a particulate resin coating such as a phenol resin coating or an acrylic resin coating is used. The same electrolytic treatment is applied to a base material having a continuous gap in the resin coating layer to form an anodic oxide film on the surface of the base material, and the formed anodic oxide film, Metal (silver, copper or both) can be deposited on the particulate resin coating covering the surface.

In the above-described example, the anodic oxide film is formed on the surface of the base material having the particulate resin film by one electrolytic treatment, and at the same time, the metal is deposited on the anodic oxide film. The formation of the oxide film and the deposition of the metal may be performed in different steps. In this case, the base material on which the particulate resin film is formed is immersed in a sulfuric acid bath, an oxalic acid bath, or a mixed bath thereof to perform anodizing treatment, and thereafter, one or two of silver nitrate and copper nitrate as nitrates. One
Alternatively, the electrolytic treatment may be performed using an electrolytic solution containing one or two of silver sulfate and copper sulfate as sulfates.
Even in this manner, similar formation of the anodic oxide film and deposition of the metal on the anodic oxide film can be performed. In this case, various currents are used as the current for the electrolytic treatment, for example, a commercial power source such as AC, AC / DC superposition,
A predetermined electrolytic treatment can be performed by applying a current such as a pulse wave for flowing R or a minus wave.

Examples and Comparative Examples Example 1 In order to confirm the effects of the present invention, a base material was subjected to the following surface treatment. As Example 1, electrolytic treatment was performed using the processing apparatus shown in FIG. 1 and using an electrolytic solution obtained by adding 5 g / L of silver sulfate as a sulfate to a sulfuric acid bath of 200 g / L of sulfuric acid. Aluminum as base material (material: A10
50) Plate (100mm long x 50mm wide x 1 thickness)
mm), this plate is the anode (plus) side,
The carbon electrode was the cathode (negative) side. The temperature of the electrolytic solution at the time of the electrolytic treatment was 5 ° C., and during the electrolytic treatment, an AC / DC superimposed current with a current ratio of AC to DC of 1: 1 was applied, and the current density was 3.0 A / dm ² . . The electrolytic treatment was performed for 30 minutes under the conditions described above, and the thickness of the anodic oxide film formed on the surface of the base material was measured, and the color tone of the surface was examined.

[0037] As Example 2 Example 2 was subjected to electrolytic treatment using an electrolytic solution prepared by adding 5 g / l of copper sulfate as a sulfate salt in sulfuric acid bath of sulfuric acid 200 g / l. The same base material as in Example 1 was used, and the base material was subjected to electrolytic treatment under the same conditions as in Example 1 to measure the thickness of the anodic oxide film formed on the surface of the base material. The color of the surface was examined. Example 3 As Example 3, an electrolytic treatment was performed using an electrolytic solution in which 5 g / l of silver nitrate was added as a nitrate to a sulfuric acid bath of 150 g / l of sulfuric acid. The same base material as in Example 1 was used, and the base material was subjected to electrolytic treatment under the same conditions as in Example 1 to measure the thickness of the anodic oxide film formed on the surface of the base material. The color of the surface was examined.

[0038] Example 4 Example 4, using the processing device shown in FIG. 1, sulfuric acid 23
2 g of copper nitrate as a nitrate in a 0 g / liter sulfuric acid bath
Electrolytic treatment was performed using an electrolytic solution to which liter was added.
A fiber cloth (length: 200 mm × width: 200 mm × thickness: 1.0 mm) made of aluminum (material: A1050) was used as a base material, and this fiber cloth was used as an anode (plus) side and a carbon electrode was used as a cathode (minus) side. The temperature of the electrolytic solution at the time of the electrolytic treatment was 20 ° C., and during the electrolytic treatment, a current of AC / DC superposition with an AC / DC current ratio of 2: 1 was applied, and the current density was 2.0 A / dm ² . . The electrolytic treatment was performed for 30 minutes under the conditions described above, and the thickness of the anodic oxide film formed on the surface of the base material was measured, and the color tone of the surface was examined.

[0039] As Example 5 Example 5, using the processing device shown in FIG. 1, sulfuric acid 23
10 g of silver sulfate as sulfate in a 0 g / liter sulfuric acid bath
The electrolytic treatment was performed using an electrolytic solution to which 1 / liter was added. Aluminum alloy as base material (material: ADC12)
Plate (length 70mm x width 150mm x thickness 5mm)
This plate was used as the anode (plus) side, and the carbon electrode was used as the cathode (minus) side. The temperature of the electrolytic solution at the time of the electrolytic treatment was 15 ° C., and during the electrolytic treatment, a current of AC / DC superposition with a current ratio of AC to DC of 1: 1 was applied, and the current density was 4.0 A / dm ² . . The electrolytic treatment was performed for 30 minutes under the conditions described above, and the thickness of the anodic oxide film formed on the surface of the base material was measured, and the color tone of the surface was examined.

[0040] As Example 6 Example 6, using the processing device shown in FIG. 1, sulfuric acid 25
10 g of silver nitrate as nitrate in a 0 g / liter sulfuric acid bath
The electrolytic treatment was performed using an electrolytic solution to which 1 / liter was added. Aluminum (Material: A2024) plate as base material (length 50 mm x width 150 mm x thickness 0.8 mm)
This plate was used as the anode (plus) side, and the carbon electrode was used as the cathode (minus) side. The temperature of the electrolytic solution at the time of the electrolytic treatment was 5 ° C., and during the electrolytic treatment, an AC / DC superimposed current with a current ratio of AC to DC of 1: 1 was applied, and the current density was 3.0 A / dm ² . . The electrolytic treatment was performed for 60 minutes under the conditions described above, and the thickness of the anodic oxide film formed on the surface of the base material was measured, and the color tone of the surface was examined.

[0041] As Example 7 Example 7, using the processing device shown in FIG. 1, sulfuric acid 15
10 g of silver nitrate as nitrate in a 0 g / liter sulfuric acid bath
The electrolytic treatment was performed using an electrolytic solution to which 1 / liter was added. Using aluminum (material: A3004) rice cooker inner pot (the inner surface is coated with fluorine) as the base material,
The rice cooker inner pot was used as an anode (plus) side, and the carbon electrode was used as a cathode (minus) side. The temperature of the electrolytic solution at the time of the electrolytic treatment was 5 ° C., and during the electrolytic treatment, an AC / DC superimposed current with a current ratio of AC to DC of 1: 1 was applied, and the current density was 3.0 A / dm ² . . The electrolytic treatment was performed for 30 minutes under the conditions described above, and the thickness of the anodic oxide film formed on the surface of the base material was measured, and the color tone of the surface was examined.

Example 8 Example 8 uses the processing apparatus shown in FIG.
10 g of silver nitrate as nitrate in a 0 g / liter sulfuric acid bath
The electrolytic treatment was performed using an electrolytic solution to which 1 / liter was added. An aluminum (material: A6063) plate (length 50 mm × width 100 mm × thickness 1 mm) was used as a base material, and this plate was used as an anode (plus) side and a carbon electrode was used as a cathode (minus) side. The temperature of the electrolytic solution at the time of the electrolytic treatment was 5 ° C., and during the electrolytic treatment, an AC / DC superimposed current with a current ratio of AC to DC of 1: 1 was applied, and the current density was 3.0 A / dm ² . . The electrolytic treatment was performed for 50 minutes under the conditions described above, and the thickness of the anodic oxide film formed on the surface of the base material was measured, and the color tone of the surface was examined.

Comparative Example 1 As Comparative Example 1, the treatment apparatus shown in FIG.
The electrolytic treatment was performed using a sulfuric acid bath of 0 g / liter (containing neither a metal nitrate nor a sulfate) as an electrolytic solution. Aluminum as base material (material: A1050)
Plate (100mm long x 150mm wide x 1m thick)
m), the plate was used as the anode (plus) side, and the carbon electrode was used as the cathode (minus) side. The temperature of the electrolytic solution at the time of the electrolytic treatment was 5 ° C., and during the electrolytic treatment, an AC / DC superimposed current with a current ratio of AC to DC of 1: 1 was applied, and the current density was 3.0 A / dm ² . . The electrolytic treatment was performed for 30 minutes under the conditions described above, and the thickness of the anodic oxide film formed on the surface of the base material was measured, and the color tone of the surface was examined.

[Thickness of coating film and color tone]
Table 1 shows the thickness of the anodized film formed on the surface of the base material and the color tone of the surface in Comparative Example 8 and Comparative Example.

[0045]

[Table 1] As can be understood from Table 1, in Examples 1 and 3 to 8, the color tone of the anodic oxide coating formed on the surface of the base material is golden to ocher or violet brown, and such a color tone is This is because silver or copper, which is a metal of nitrate or sulfate, was precipitated, and the deposition of silver or copper could be confirmed visually. In Comparative Example 1, the nitrate and the sulfate were not added at all, so that no metal was deposited and an anodic oxide film was formed. However, the color tone of the surface was almost colorless and transparent, This indicates that no precipitation occurred.

[Thermal Conductivity Test] In order to confirm the thermal conductivity, the following test was performed. In Example 9, an aluminum (material: A1050) plate (length 100 mm × width 50 mm × thickness 1 mm) was used as a base material, and a 4 μm anodic oxide film was formed on the surface of the base material under the same conditions as in Example 1. Formed. Then, the thermal conductivity of the plate of Example 9 was measured. Further, in Example 10, the same base material as that of Example 9 was used, and an anodic oxide film having a thickness of 25 μm was formed on the surface of the base material under the same conditions. Using the base material,
Under the same conditions, a 50 μm anodic oxide film was formed on the surface of the base material, and the thermal conductivity of the plates of Examples 10 and 11 was measured. These measurement results are as shown in Table 2.

As a comparative example 2, a plate made of aluminum (material: A1050) as a base material of the ninth embodiment, and as a comparative example 3, an aluminum having a hard alumite film (anodized film without deposition of metal) having a thickness of 50 μm. The thermal conductivity of the plate (same as the plate of Example 9) was measured, and the results are shown in Table 2.

[0048]

[Table 2] As can be understood from Table 2, the plates of Examples 9 to 11, that is, the plates having the anodic oxide coating on which silver as a metal is deposited, have almost the same thermal conductivity as the aluminum base material as the base material, and Above ℃, the plates of Examples 9 to 11 are larger than the aluminum cloth. On the other hand, the heat conductivity of the plate of Comparative Example 3, that is, the plate having a mere hard alumite coating, is smaller than the heat conductivity of the aluminum fabric by about 1/3. From these facts, it was confirmed that the thermal conductivity was increased by the precipitation of silver as a metal of the nitrate, and the thermal conductivity was greatly improved.

[Antibacterial test] To confirm the antibacterial properties,
The following experiment was performed. As Example 12, an antibacterial test was carried out using an electrolytically treated one in the same manner as in Example 3 (having the same surface treatment as in Example 3 and having a surface anodic oxide film having a thickness of 30 μm). Was. In the antibacterial activity test, bacterial liquids containing Escherichia coli, Staphylococcus aureus, Vibrio parahaemolyticus and Salmonella were each dropped, stored for 24 hours in an atmosphere at an ambient temperature of 35 ° C., and the number of viable bacteria after 24 hours was measured.

As Comparative Example 4, an electrolytic treatment was performed in the same manner as in Example 3 except that a solution obtained by removing silver nitrate from the electrolytic solution in Example 3 was used (an anodic oxide film having a thickness of 30 μm was present on the surface). An antibacterial activity test was performed in the same manner as in Example 12 except that silver was not precipitated.

[0051]

[Table 3] The measurement results of Example 12 and Comparative Example 4 are as shown in Table 3. In Comparative Example 4, Escherichia coli, Staphylococcus aureus, Vibrio parahaemolyticus, and Salmonella survived even after 24 hours, but in Example 12, the number of surviving bacteria after 24 hours could not be detected. . From these, it was confirmed that excellent antibacterial properties were obtained by depositing silver on the anodized film.

[Odor test] As Example 13, Example 1
An odor test was carried out using the electrolytically treated product in the same manner as in Example 2. In the odor test, 1 liter of river water was put into a beaker, the one subjected to the electrolytic treatment in Example 13 was immersed therein, and the degree of odor emitted from the beaker after one week had elapsed was examined. Further, as Comparative Example 5, an odor test was conducted in the same manner as in Example 13 by using an electrolytically treated one in the same manner as in Comparative Example 4, and the degree of odor was examined.

In Example 13, almost no odor was emitted even after one week, whereas in Comparative Example 5, an odor was emitted. From these facts, it was confirmed that excellent deodorizing property was obtained by depositing silver on the anodized film. [Fire Resistance Test] In order to confirm the fire resistance performance, the following experiment was performed. As Example 14, Example 8 (Material: A60
A fire resistance test was carried out using an electrolytically treated one in the same manner as in (63). In the fire resistance test, a gas burner flame was exposed to the electrolytic treatment in Example 14. The flame temperature of the gas burner was 1400 ° C., and heating was performed with a flame of the gas burner at intervals of 150 mm, and the heating time was 20 seconds.

For comparison, Comparative Example 2 was used as Comparative Example 6.
(Material: A1050) The same as in Example 14 was used, which had been subjected to electrolytic treatment in the same manner as in Example 14, and used as a comparative example 7 was a plate made of aluminum (material A6063) (having no electrolytic treatment). And a fire resistance test was performed.

[0055]

[Table 4] The results of the fire resistance tests of Example 14 and Comparative Examples 6 and 7 are shown in FIG.
In Example 14, there was no change in surface color or shape even after heating. In contrast,
In Comparative Example 6, the surface color was lightened and its shape was slightly deformed. In Comparative Example 7, although the surface color was not changed, its shape was greatly bent and deformed. From these, the presence of an anodic oxide film on the surface of the aluminum plate improves the fire resistance performance compared to that of the fabric, and when silver is deposited on this anodic oxide film, the fire resistance performance is further improved, It was confirmed that sufficient refractory performance was obtained by depositing silver.

[Silver Precipitation Confirmation Test] In Example 15, a fluororesin film was formed on a part of the surface of an aluminum (A3004) plate, and the plate having the fluororesin film was electrolyzed under the same conditions as in Example 1. Process,
An anodic oxide film of 30 μm was formed on the surface (the portion where no fluororesin film was present). In the plate of Example 15 thus prepared, the surface of the aluminum portion (the portion where the fluororesin film does not exist) has a golden color, which indicates that silver is deposited on the generated anodized film. On the other hand, the fluororesin film portion was subjected to electrolytic treatment, but no change in appearance was observed.

In order to confirm whether or not silver was precipitated on the plate of Example 15, a silver deposition confirmation test was performed. This confirmation test was performed by observing the aluminum part and the fluororesin part of the plate of Example 15 with a scanning electron microscope from the aluminum part side and the fluororesin coating part side.
The presence of silver was examined by the line diffraction method. The result of the aluminum portion is as shown in FIG. 4, in which silver is deposited and present. In addition, the result of the fluororesin coating part,
As shown in FIG. 5, silver is also precipitated and present in this portion. From these, it was confirmed that silver as a metal of nitrate was deposited on the anodic oxide film and the fluororesin film.

[Cooking rice heat retention test] In order to confirm the rice cooking heat retention performance, the following experiment was conducted. Example 16 As Example 16, a rice cooking heat retention test was performed using a rice cooker subjected to electrolytic treatment in the same manner as in Example 7. In the rice cooker heat retention test, rice was cooked using the rice cooker electrolyzed in Example 16 (the inner surface of the cooker inner cooker was coated with a fluororesin coating, and a metal of silver nitrate was deposited on the fluororesin coat). At the time of cooking, changes in the color and odor of cooked rice on the first, second, and third days after the cooking were examined. Further, as Comparative Example 8, rice was cooked using a conventional rice cooker without electrolytic treatment (in which the inner surface of the rice cooker was simply coated with a fluororesin), and cooked in the same manner as in Example 16. When raising, 1 from cooking
The changes in the color and odor of the cooked rice on the second, third and third days were examined.

[0059]

[Table 5] The results of Example 16 and Comparative Example 8 are as shown in Table 5. In the rice cooker of Example 16, there was no change in the color of the cooked rice even after three days had elapsed after cooking, and no odor was generated. Was.
On the other hand, in the rice cooker of Comparative Example 8, the color of the cooked rice began to turn yellow on the second day after cooking, and the smell was 1 after cooking.
On the day, the smell began to come out, and on the second day after cooking, a strong smell began to be emitted. From these facts, it was possible to confirm the deposition of silver on the anodic oxide film on the surface of the base material, and it was also possible to confirm the deodorizing effect of the deposited silver.

[0060]

According to the surface treatment method of the first aspect of the present invention, an anodic oxide film is formed on the surface of a base material formed of aluminum or an alloy thereof, and nitrate or sulfuric acid added to the anodic oxide film is simultaneously formed. The metal of the salt can be deposited, and the formation of the anodic oxide film and the deposition of the metal can be performed by a single electrolytic treatment, thereby simplifying and shortening the electrolytic treatment step, and The cost required for the surface treatment can be reduced. And
In the base material subjected to such a surface treatment, silver (or copper, silver and copper) is precipitated on the anodic oxide film on the surface, so that antibacterial properties, deodorizing properties, heat conductivity, and conductivity are enhanced. .

According to the surface treatment method of the second aspect of the present invention, the surface of the base material is passed through fine voids of the particulate resin film formed on at least a part of the base material formed of aluminum or its alloy. Along with forming the anodized film, nitrate or sulfate metals (silver, copper, silver and copper) added to the formed anodized film can be deposited. Even in the base material subjected to such a surface treatment, silver (or copper, silver, and copper) is deposited on the formed anodic oxide film, so that the base material has antibacterial properties, deodorizing properties, thermal conductivity, and conductivity. Is enhanced. According to the surface treatment method of claim 3 of the present invention, an anodic oxide film is formed on the surface of the base material through a fluororesin film on one surface of the base material, and the formed anodic oxide film is formed of nitrate or sulfate. A metal can be deposited, and an anodized film can be directly formed on the other surface of the base material, and a metal of nitrate or sulfuric acid can be deposited on the formed anodized film.

According to the surface treatment method of the present invention, the base material having the particulate resin film formed thereon is immersed in a sulfuric acid bath, an oxalic acid bath, or a mixed bath thereof to perform anodizing treatment. Thereafter, two steps of performing an electrolytic treatment with an electrolytic solution to which one or two of silver nitrate and copper nitrate as nitrates, or one or two of silver sulfate and copper sulfate as sulfates are added. By forming an anodized film on the surface of the base material having a particulate resin film,
A nitrate or sulfate metal can be deposited on the formed anodic oxide film. According to the surface treatment method of the fifth aspect of the present invention, the nitrate or sulfate metal precipitates on the particulate resin coating in addition to the anodic oxide coating on the base material. , Deodorization, thermal conductivity, conductivity, etc. can be further enhanced.

According to the surface treatment method of claim 6 of the present invention, since the particulate resin coating is a fluororesin coating, a phenolic resin coating or an acrylic resin coating, the electrolytic solution to be subjected to the electrolytic treatment is applied to these resin coatings. It acts on the surface of the base material through the existing voids, so that the base material can be subjected to a predetermined electrolytic treatment.

According to the surface treatment method of the present invention, an anodic oxide film is formed on the surface of a base material of aluminum or aluminum alloy, and silver (or copper, silver and copper) is formed on the anodic oxide film. ), Antibacterial,
Good deodorization, heat conductivity, conductivity, can be conveniently applied to pots, kettles, hot plates, dishes, kettles, and foils wrapping foods, and by applying to them, the safety of foods and cooked goods And the heating efficiency when performing heating cooking can be improved. Further, an anodic oxide film is formed on the surface of the base material through the particulate resin film on the surface of the aluminum or aluminum alloy base material, and silver (or copper, silver and copper) is deposited on the formed anodic oxide film. Therefore, antibacterial property, deodorization property, heat conductivity, and conductivity are enhanced despite the application of the particulate resin coating, and it can be conveniently applied to pots (cooking pots, etc.) and pots (rice cooker inner pots, etc.) By applying to these, the safety of foods and cooked products can be improved, and the heating efficiency when performing heating cooking can be improved.

Further, according to the surface treatment method of the present invention, since the anodic oxide film is formed on the surface of the base material,
The wear resistance and hardness of the base material can be sufficiently increased, and since the metal of nitrate or sulfate is deposited on the anodic oxide film, the thermal conductivity of the anodic oxide film, in other words, the heat dissipation, must be improved. From these, building materials,
It can be conveniently applied to members for traffic or transportation equipment, and by applying to such members, the fire resistance, abrasion resistance and hardness of this member can be increased.

[Brief description of the drawings]

FIG. 1 is a simplified diagram schematically showing an example of a processing apparatus for performing an embodiment of a surface treatment method according to the present invention.

FIG. 2 is a partially enlarged cross-sectional view showing a part of a base material processed by the processing apparatus of FIG. 1 in an enlarged and simplified manner.

FIG. 3 is a partially enlarged cross-sectional view showing a part of another base material processed by the processing apparatus of FIG. 1 in an enlarged and simplified manner.

FIG. 4 shows an aluminum part of the plate of Example 15
It is a figure showing the result of having investigated by the line diffraction method.

FIG. 5 is a view showing a result of examining a fluororesin coating portion of a plate of Example 15 by an X-ray diffraction method.

[Explanation of symbols]

 2 Electrolyte 4,6 Electrode 12,14,32 Base material 16 DC power supply 18 AC power supply 22,34 Anodized film 24,36 Barrier layer 26,38 Porous layer 30,42 Precipitated metal

Claims (8)

[Claims] 1. A base material formed of aluminum or an alloy thereof is placed in a sulfuric acid bath, an oxalic acid bath or a mixed bath thereof as a metal nitrate, one or two of silver nitrate and copper nitrate or a metal nitrate. In an electrolytic solution to which one or two of silver sulfate and copper sulfate as sulfates are added, AC / DC superposition, PR is applied by passing a minus wave, or a pulse wave is applied by passing a minus wave. A surface treatment method for aluminum or an alloy thereof, wherein an anodized film is formed on the surface of the base material, and at the same time, an added nitrate or sulfate metal is deposited on the anodized film. 2. After forming a particulate resin coating on at least a part of the surface of a base material formed of aluminum or an alloy thereof, the base material having the particulate resin coating is subjected to a sulfuric acid bath,
One or two of silver nitrate and copper nitrate as a metal nitrate, or one or two of silver sulfate and copper sulfate as a metal sulfate were added to an oxalic acid bath or a mixed bath thereof. In the electrolytic solution, AC / DC superposition, PR for flowing a negative wave or a pulse wave current for flowing a negative wave is applied for electrolytic treatment, thereby forming an anodized film on the surface of the base material, and simultaneously adding nitrate or A method for surface-treating aluminum or an alloy thereof, wherein a metal of sulfate is deposited on the anodic oxide film. 3. A fluororesin film as the particulate resin film is formed on one surface of the base material, and the base material is subjected to an electrolytic treatment in the electrolytic solution, so that one surface of the base material passes through the fluororesin film. At the same time as forming the anodic oxide film, the metal of nitrate or sulfate added to the anodic oxide film was precipitated, and at the same time as forming the anodic oxide film on the other surface of the base material, the metal was added to the anodic oxide film. 3. The method according to claim 2, wherein a metal of nitrate or sulfate is deposited. 4. A particulate resin film is formed on at least a part of the surface of a matrix formed from aluminum or an alloy thereof, and the matrix having the particulate resin film is treated with a sulfuric acid bath, an oxalic acid bath, or a mixture thereof. Anodized by immersing in a mixed bath to form an anodized film on the surface of the base material, and then as one or two of silver nitrate and copper nitrate as a metal nitrate, or as a metal sulfate Characterized in that aluminum is subjected to electrolytic treatment in an electrolytic solution to which one or two of silver sulfate and copper sulfate are added, thereby precipitating a metal of nitrate or sulfate added to the anodic oxide film. Or a surface treatment method for the alloy. 5. The electrolytic treatment of the base material,
The method for treating aluminum or an alloy thereof according to claim 2 or 4, wherein a metal of added nitrate or sulfate is deposited on the anodized film and the particulate resin film. 6. The method according to claim 1, wherein the particulate resin film is a fluororesin film,
The surface treatment method for aluminum or its alloy according to claim 2, 4 or 5, which is a phenol resin film or an acrylic resin film. 7. The base material is a pot, a pot, a hot plate,
The surface treatment method for aluminum or an alloy thereof according to any one of claims 1 to 6, wherein the method is a tableware, a kettle, or a foil. 8. The method according to claim 1, wherein the base material is a building member or a member for transportation or transportation equipment.