JPH07228996A - Production of metallic foil - Google Patents

Abstract

PURPOSE:To obtain metallic foil having consistent and good quality with good productivity and to prolong the life of a cathode body by subjecting the surface of the cathode body exposed after peeling to electrolytic oxidation at the time of producing the foil by peeling an electrodeposited metallic thin film from the surface of the cathode body. CONSTITUTION:An electrolytic treating liquid holding part 14 of an anodically oxidized film forming device 11 is brought into elastic contact with the surface 3a exposed after the metallic foil of the cathode body 3 rotating in a direction p is peeled and is rotated into a direction r. The electrolytic treating liquid 15a is supplied in this state to a pipe 15 and is dropped from apertures 15b onto the electrolytic treating liquid holding part 14 so as to be impregnated therein. Consequently, the conductive roll 13 and the surface 3a of the rotary cathode body 3 are made conducting via the electrolytic treating liquid 15a. Terminals 13a, 13a installed to the conductive roll 13 are then connected to a minus side of a power source and an electrolytic current is passed between the conductive roll 13 and the rotating cathode body 3, by which the surface 3a is continuously or intermittently anodically oxidized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a metal foil, more specifically, an anode body and a cathode body are arranged in an electrolytic cell filled with a predetermined electrolytic solution, and an electric current is applied between them. After depositing a predetermined metal on the surface of the cathode body by advancing the electrolytic reaction, the thin metal layer is peeled from the surface of the cathode body to produce a metal foil such as an electrolytic copper foil. The present invention relates to a method for producing a metal foil, which can extend the service life of the cathode body and improve the properties of the obtained metal foil.

[0002]

2. Description of the Related Art Metal foils of iron, copper, chromium, nickel or the like, or alloy foils of these metals, generally contain a predetermined amount of ions of these metals between an insoluble cathode body and an insoluble anode body. The target metal is deposited on the surface of the cathode body to a desired thickness by conducting an electrolytic reaction while supplying the electrolytic solution of to form a thin metal layer, and then the formed thin metal layer is formed into a cathode body. It is manufactured by peeling from the surface. In that case, a drum-shaped or plate-shaped cathode body is used.

By the way, the production of the above-mentioned metal foil is performed by using the method shown in FIG.
It is customary to use an apparatus having a structure as shown in FIG. That is, first, in the electrolytic cell 1, an insoluble anode body 2 made of, for example, lead and an insoluble rotating cathode body 3 made of, for example, titanium, stainless steel, or chromium-coated stainless steel and having a drum shape are arranged at predetermined intervals. Are arranged so as to face each other with a gap 4 therebetween, and the tank is filled with, for example, an electrolytic solution 5 of a predetermined type and concentration.

Then, the rotating cathode body 3 is rotated as shown by an arrow p while supplying the electrolytic solution 5 to the gap 4 by the distributor (electrolytic solution outlet) 6, so that the rotating cathode body 3 is rotated between the anode body 2 and the rotating cathode body 3. The electrolytic reaction proceeds by energizing at a predetermined current density. A metal is electrodeposited on the surface 3a of the rotating cathode body 3 with a predetermined thickness, and a thin layer of the electrodeposited metal is peeled off from the surface 3a of the rotating cathode body 3 as a metal foil,
The obtained metal foil 7 is passed through the guide rollers 8a and 8b,
It is wound by the winder 9, and desired metal foils are continuously produced here.

[0005]

By the way, when the above-mentioned conventional apparatus is operated for a long period of time, metal deposition on the surface of the cathode body may occur due to repeated electrodeposition of metal and peeling of the metal foil. The bare surface 3a of the rotating cathode body 3 exposed after the foil 7 has been peeled off becomes non-uniform due to long-term exposure to an atmosphere containing oxygen gas generated from the anode body 2 and splashes of the electrolytic solution 5. It will be oxidized. As a result, on the surface 3a, a non-uniform oxide film whose thickness varies in various places is formed. Then, when metal is electrodeposited on the rotating cathode body 3 in a state where such a nonuniform oxide film is formed on the surface 3a,
The resulting metal foil 7 has structural defects such as surface unevenness and pinholes.

In order to solve such a problem, conventionally, after continuously operating the apparatus for a predetermined time, while rotating the rotating cathode body 3, as shown in FIG.
The buff 10 rotating as indicated by the arrow q is brought into contact with a and the surface 3
The treatment is carried out by exposing the active surface of the rotating cathode body 3 by buffing a and removing the uneven oxide film formed on the surface 3a. This procedure is performed cyclically, which
The quality of the metal foil produced is kept constant. When manufacturing an electrolytic copper foil, buffing is usually performed, for example, about every 48 hours.

However, in order to keep the quality of the metal foil constant, it is indispensable to perform the buffing in a predetermined cycle while operating the apparatus, and therefore, the buffing is performed in the process of performing the buffing. Since the metal foil used as a product does not have the properties of a product, it must be discarded. This causes a problem that the productivity of the metal foil is reduced.

Further, foreign substances such as polishing powder and buff pieces are generated in the process of buffing, and defective products may be produced in the metal foil due to the inclusion of these foreign substances in the electrolytic solution. Further, the buffing abrades the surface of the cathode body, especially both ends of the surface of the cathode body, and shortens the service life of the cathode body. Therefore, the frequency of exchanging the cathode body increases, which causes an increase in manufacturing cost.

On the other hand, the former East German publication: DD 21
7 828 A1 discloses a method of forming an oxide film on the surface by anodizing a titanium or titanium alloy cathode body used for copper foil production. In this method, a part or all of the cathode body is immersed in an electrolytic solution such as sulfuric acid to generate an electrolysis voltage of 15 to 40 V and a current density of 50 to 3
Anodization is performed for 10 to 60 minutes under the condition of 00 mA / dm ² .

However, this prior art only discloses that after the anodizing treatment of the cathode body, the treated cathode body is placed in an electrolytic bath for copper foil production to produce the copper foil. . Further, in the case of continuously producing a copper foil using this prior art, the process of producing the copper foil has to be interrupted once when performing the anodizing treatment on the surface of the cathode body. That is, when the copper foil is manufactured using the above-mentioned prior art, the productivity in continuously producing a long copper foil is low.

The present invention solves the above-mentioned problems in the continuous production of metal foils and forms a uniform oxide film on the surface of the cathode body to be used, thereby eliminating the need for conventional buffing. It is an object of the present invention to provide a metal foil manufacturing method capable of manufacturing a metal foil having a constant quality and a good quality and extending the service life of the cathode body.

[0012]

In order to achieve the above-mentioned object, in the present invention, an electric current is caused to flow between an anode body and a cathode body which are immersed in an electrolytic solution to cause an electrolytic reaction. When a metal thin layer is formed by electrodepositing a metal on the surface of the cathode body and then the metal thin layer is peeled from the surface of the cathode body to continuously produce a metal foil, the metal thin layer is used. The method for producing a metal foil is characterized in that the surface of the cathode body exposed after peeling is electro-oxidized continuously or intermittently to form an anodic oxide film on the exposed surface.

The greatest feature of the method of the present invention is that the exposed surface of the cathode body from which the metal foil has been peeled off is not harmful to electrodeposition of the metal on the surface of the cathode body while operating the apparatus for producing the metal foil. The point is to form a uniform anodic oxide film having a uniform thickness. In particular, according to the method of the present invention, since the exposed surface of the cathode body can be anodized online, an extremely thin oxide film having a certain thickness can be secured on the surface of the cathode body,
This has the advantage that a thin electrolytic metal foil having relatively stable mechanical properties can be manufactured for a long time.

This uniform anodic oxide film has corrosion resistance itself. Therefore, even if exposed to oxygen gas generated from the anode body or droplets of the electrolytic solution generated during the electrolytic reaction during the production of the metal foil for a long time, non-uniform oxidation on the exposed surface of the cathode body after peeling the metal foil occurs. It functions as a protective film that prevents the formation of a film. As a result, the produced metal foil can effectively prevent the occurrence of surface defects and texture defects such as pinholes.

Further, since this anodic oxide film has a good releasability from the thin metal layer formed thereon, metal fatigue on the surface of the cathode body due to repeated electrodeposition of metal and peeling of the metal foil. Effectively suppress the occurrence of. Therefore, in the case of the cathode body on which this anodized film is not formed, the occasional localized damage on the surface of the cathode body is prevented.

As described above, according to the method of the present invention, the extremely thin uniform anodic oxide film described above is continuously formed on-line or intermittently as necessary on the surface of the cathode body. It can be maintained in a stable and uniform state for a long period of time. Therefore, it is not necessary to perform buffing in a short cycle as in the conventional case. This anodic oxide film is formed by mounting an anodic oxide film forming device, which will be described later, on the surface of the cathode body that is exposed after the metal foil is peeled off, and operating the device continuously or intermittently. .

In this case, the anodic oxide film forming apparatus 11 is
As shown in FIG. 2, the surface 3 a of the cathode body 3 is mounted at a position in the front stage where the surface 3 a contacts the electrolytic solution 5. Therefore, the electrodeposition of the metal on the cathode body 3 proceeds on the anodized film formed by operating the anodized film forming apparatus prior to the electrolytic reaction.

An example of the anodized film forming apparatus of the present invention is shown in FIG. In the case of this example, the device has a shaft 12 for mounting the device in the center, and at the time of anodization, a conductive roll 13 that functions as a counter electrode facing the rotating cathode body 3, and a conductive roll 13 is arranged so as to surround this conductive roll. It is configured by an electrolytic treatment liquid holding portion 14 for anodization provided and a pipe which is an electrolytic treatment liquid supply means 15 for supplying the electrolytic treatment liquid 15a for anodization to the electrolytic treatment liquid holding portion. . Then, with the electrolytic treatment liquid holding portion 14 in contact with the surface 3a of the rotating cathode body 3 shown by the phantom line, the shaft 12 is rotatably supported by means (not shown) so that the entire apparatus 11 is As shown in (3), it is mounted on the surface 3a of the rotating cathode body 3.

As the conductive roll 13, a roll made entirely of a material having corrosion resistance such as titanium, nickel, chromium, copper, and stainless, or the surface of these materials, for example, silver, silver alloy, gold, gold alloy It is also possible to use a material such as palladium, palladium alloy, etc., which is coated with a material that is electrically conductive and, at the same time, has corrosion resistance to the electrolytic treatment liquid used for anodization. In addition, the surface of the roll made of non-conductive plastic material such as polypropylene or polyvinyl chloride is covered with a foil or wire or mesh made of a material having conductivity and corrosion resistance, or the roll surface has conductivity and corrosion resistance. Plating material with
A coated product can be used. In short, at least the surface of the roll having conductivity and corrosion resistance is used as a counter electrode for electrolytic oxidation of the surface of the cathode body.

The electrolytic treatment liquid holding portion 14 surrounding the conductive roll (counter electrode) 13 has liquid permeability and appropriate elasticity. This electrolytic treatment liquid holding part 1
4 is a material having corrosion resistance to the electrolytic treatment liquid used,
For example, it is formed by covering the periphery of the conductive roll 13 with polyurethane, polyvinyl formal or polyester felt, non-woven fabric, split yarn, or the like.

A pipe 15 having a plurality of openings 15b in the axial direction of the electrolytic treatment liquid holding portion 14 is arranged above the electrolytic treatment liquid holding portion 14, and the pipe 15 has a pump 15c. The predetermined electrolytic treatment liquid 15a is supplied by the. Electrolytic treatment liquid 15 supplied
Although a is not particularly limited, those which do not harm the production of the metal foil even when mixed with the electrolytic solution used for the production of the metal foil are used. For example, in the production of the metal foil, the surface of the cathode body is used. It is possible to use the same electrolyte as the one currently used for electrodepositing the metal, or one having the same components as the above electrolyte but having different component ratios.

As the electrolytic solution, for example, an aqueous solution of copper sulfate can be used when manufacturing an electrolytic copper foil, an aqueous solution of nickel sulfate or nickel sulfamate when manufacturing a nickel foil, and an aqueous solution of zinc sulfate when manufacturing a zinc foil. . In addition, when these electrolytic solutions currently used for forming the thin metal layer or electrolytic solutions having the same composition but different composition ratios are used, the temperature is dissolved in the electrolytic solution. It is preferable to set the temperature higher than the deposition temperature of the electrolyte used.

When the temperature of the electrolytic solution is set to a temperature lower than the deposition temperature of the electrolyte dissolved in the electrolytic solution, the deposition of the electrolyte occurs, which adheres to the surface of the cathode body to hinder the anodization. This is because a microstructure defect locally occurs in the metal foil due to the above, and thus mechanical properties of the metal foil are deteriorated and a bump-like structure on the surface of the metal foil is likely to occur.

Further, as the electrolytic treatment liquid 15a to be supplied, it is possible to use a liquid which does not contain metal ions deposited on the surface 3a of the cathode body 3. Examples of such an electrolytic treatment solution include acidic aqueous solutions such as aqueous sulfuric acid solution, aqueous phosphoric acid solution and aqueous hydrochloric acid solution, and neutral aqueous solutions in which sodium sulfate, potassium sulfate, sodium chloride, potassium chloride and the like are dissolved. . Among them, a sulfuric acid aqueous solution is suitable for producing a copper foil.

When a sulfuric acid aqueous solution is used as the electrolytic treatment liquid, its concentration is preferably 10 g / l or less. The reason is as follows. In FIG. 2, the sulfuric acid aqueous solution used for anodizing the surface of the cathode body 3 flows down along the surface of the cathode body 3 to the liquid surface of the electrolytic cell 1. Then, almost no electrolytic current flows on the surface of the cathode body 3 located below the device 11 after the electrolytic oxidation treatment, and therefore, the anodic oxide film does not grow. Therefore, if an aqueous solution of sulfuric acid having a concentration of more than 10 g / l flows down here, erosion of the thin anodic oxide film having a uniform thickness may occur.

The means for supplying the electrolytic treatment liquid for anodic oxidation is not limited to the pipe type described above. For example, the conductive roll 13 is a hollow body and a large number of openings are formed on the peripheral surface thereof. By supplying the electrolytic treatment liquid to the hollow portion of the conductive roll 13, the electrolytic treatment liquid may be supplied from the inside to the electrolytic treatment liquid holding portion 14 through the opening of the peripheral surface thereof.

When the apparatus 11 is used, the anodized film on the surface of the cathode body is formed as follows. First, the surface 3a of the rotating cathode body 3 rotating as indicated by the arrow p.
Then, the electrolytic treatment liquid holding portion 14 of the device 11 is brought into contact with the elastic treatment liquid holding portion 14 with elasticity. Therefore, the electrolytic treatment solution holder 14 automatically rotates in the direction of arrow r in the figure. While maintaining this state, a predetermined electrolytic treatment liquid 15a is supplied to the pipe (electrolytic treatment liquid supply means) 15.

The electrolytic treatment liquid 15a is dripped into the electrolytic treatment liquid holding portion 14 from the opening 15b to impregnate the inside of the electrolytic treatment liquid holding portion 14 and is held therein. As a result, the conductive roll (counter electrode for electrolytic oxidation) 13 and the rotating cathode body 3
The surface 3a is electrically connected through the electrolytic treatment liquid 15a.

Next, the terminals 13a, 13a attached to the conductive roll 13 are connected to the negative side of the power source (not shown), and the surface 3a of the rotating cathode body 3 is connected to the positive side of the power source, and the conductive roll 13 is connected. And the surface 3a of the rotating cathode body 3
During this period, an electrolytic current is passed to anodize the surface 3a. At this time, the conductive roll (counter electrode) is energized so that the potential becomes lower than the potential when the metal foil is electrodeposited on the surface of the rotating cathode, and at the same time the potential of the anode rotates. It is necessary to make it higher than the potential of the cathode body. When the potential of the cathode body is higher than that of the anode body, metal foil is not deposited on the surface of the cathode body, or electricity is applied so that the potential of the conductive roll becomes higher than that of the rotating cathode body. And the conductive roll 13 becomes the positive electrode, and the surface 3a of the rotating cathode body 3
Is a negative electrode and the surface 3a of the rotating cathode body 3 is not anodized, which causes a disadvantage.

In this way, the surface 3 of the rotating cathode body is
An anodized film having a desired thickness is formed on a. For example, when the rotating cathode body is made of titanium, the thickness of the anodic oxide film formed is preferably 1.4 to 140 Å. When the thickness of this film is more than 140Å, the film begins to become electrically insulating and its insulating property becomes non-uniform, and the metal foil obtained by electrodeposition on the surface of the rotating cathode body has uneven surface. , Pinholes are more likely to occur. As a result, mechanical properties of the metal foil such as tensile strength and elongation are deteriorated. Also, the thickness is 1.4Å
When it becomes thinner, it functions as a protective film to protect the surface of the rotating cathode body from the oxygen gas generated from the anode body and the splash of the electrolytic solution, and it also accompanies repeated electrodeposition of metal and peeling of the thin metal layer. This is because the function of suppressing metal fatigue on the surface of the rotating cathode body is lost.

The preferred thickness of the anodic oxide film is about 50Å, although it varies depending on the roughness of the surface of the titanium rotating cathode body, the homogeneity of the structure, or the thickness of the thin metal layer to be formed. Since the anodic oxide film with a thickness of about 50Å has a relatively epitaxial or amorphous film structure with almost no anatase type crystal structure peculiar to titanium oxide, the metal thin layer formed on it is microscopic. It is considered that this is because no microstructure defect occurs at all and the microstructure becomes fine.

When an anodized film is formed on the surface of the rotating cathode body made of titanium, the surface roughness is JIS
The Rz value defined by B0601 is preferably 2.0 μm or less. Optimally a mirror surface, but Rz is 1.
About 0 μm is sufficient. The formation of this anodic oxide film may be performed continuously or intermittently.

When the target metal is electrodeposited on the surface of the rotating cathode body on which the anodic oxide film having a predetermined thickness is formed and then the thin metal layer is peeled off, a part of the anodic oxide film is also deposited on the metal foil side at the same time. Since the film is peeled off, the thickness of the anodized film is gradually reduced by repeating the electrodeposition-peeling. Therefore, in order to complement the thinned state, the formation of the anodic oxide film needs to be performed continuously or intermittently.

As a method for performing the above anodic oxidation, there are a constant current method and a constant voltage method. Among these methods, by adopting the constant voltage method that holds the potential constant, when the thin metal layer is peeled from the surface of the cathode body, the amount of the oxide film removed on the thin metal layer is automatically and automatically removed. This can be complemented immediately, and the situation in which the thickness of the oxide film grows to an unnecessarily large thickness can be suppressed.

In particular, the thinner the thin metal layer formed on the surface of the cathode body, the worse the peelability of the thin metal layer from the surface of the cathode body, and therefore the anodic oxidation that the thin metal layer removes. In such a case, it is preferable to apply the above-mentioned constant voltage method because the thickness of the film tends to increase. The rate of anodic oxidation, and thus the thickness of the anodic oxide film formed, is more than the treatment time.
It is almost determined by the electrolytic voltage used during anodizing. It is known that the adopted electrolysis voltage and the film thickness of the formed anodic oxide film are in direct proportion to each other, and that the electrolysis voltage of 1 V corresponds to the film thickness of the anodic oxide film of about 14 to 15 Å. Conference Bulletin Vol.27 No.4 2
96-298, 1988).

Therefore, as described above, since the film thickness of the anodized film is preferably 1.4 to 140Å,
When adopting the constant voltage method, set the electrolytic voltage to 0.1 to 10
It would be preferable to set it to V. FIG. 4 is a partially cutaway perspective view showing a state in which another anodized film forming apparatus 16 of the present invention is mounted on the surface of the rotating cathode body.

In the case of this device, the electrolytic treatment liquid holding portion 16a
Is a box-shaped container, and the portion on the surface 3a side of the rotating cathode body 3 is open. A plurality of electrolytically treated solution ejection holes 19a are formed in that portion, and a perforated plate body 19 having a curved surface that matches the curvature of the surface 3a of the rotating cathode body 3 is attached. This perforated plate body 19
Are liquid-tightly attached to the surface 3a of the rotating cathode body 3 and are arranged so as to be in sliding contact with or close to the surface 3a of the rotating cathode body 3.

The container 16a is made of a material having corrosion resistance to the electrolytic treatment liquid used, for example, polyvinyl chloride or polypropylene, and the porous plate body 19 may be brought into sliding contact with the surface 3a of the rotating cathode body. Therefore, it is preferable to use a material having abrasion resistance, lubricity, and elasticity, such as polyethylene, polyester, polyurethane, or silicone rubber.

A metal powder removing filter 20 is provided approximately in the center of the container 16a to divide the interior of the container 16a into two spaces, an upper space 21a and a counter electrode 1a.
7 is arranged. The electrolytic treatment liquid is supplied to the upper space 21a from the supply pipe 18c and the discharge pipe 1
8b, and the electrolytic treatment liquid is supplied from the supply pipe 18a to the lower space 21b.
It jets from 9a toward the surface 3a of the rotating cathode body.

At this time, a liquid film of the electrolytically treated liquid having a uniform thickness is formed on the surface 3a of the rotating cathode body 3. This apparatus is useful when the electrolytic treatment solution is the electrolytic solution used for producing the metal foil. When the electrolytic solution used in the production of the metal foil is pumped up and used as it is as an electrolytic treatment solution for anodizing, the electrolytic solution is formed on the surface of the counter electrode 17 when the anodized film is formed. The contained metal may be electrodeposited. Then, depending on the conditions at the time of forming the film, abnormal deposition may occur as metal powder. Then, these metal powders deposited on the counter electrode body 17 are separated from the surface of the counter electrode body 17 by the flow force of the supplied electrolytic treatment liquid, and the surface 3a of the rotating cathode body, that is, the anodized film is being formed. May move to a location.

When such a situation occurs, these metal powders are co-deposited on the surface 3a of the rotating cathode body, so that the anodic oxide film thus formed has a nodular structure mixed therein. However, in the case of this device, even if the metal powder is abnormally deposited on the counter electrode body 17 and it is separated from the surface of the counter electrode body 17, since the separated metal powder is captured or blocked by the metal powder removal filter 20, It does not move toward the lower space 21b, that is, toward the surface 3a of the rotating cathode body. In this way, the metal powder removing filter 20 functions to prevent these detached metal powders from being co-deposited on the surface 3a of the rotating cathode body so that the anodic oxide film is mixed with a bump-like structure.

The metal powder removing filter 20 having such a function may be a film having fine pores.
Corrosion-resistant cloth that does not allow passage of ion-exchange resin membranes or metal powder but allows passage of metal ions may be used. When the ion exchange resin film is used, the effect of preventing the movement of the metal powder described above and the effect of preventing the metal electrodeposition on the counter electrode 17 can be obtained.

In this case, the electrolytic solution for producing the metal foil is supplied as it is to the upper space 21a as an electrolytic treatment solution, and the electrolytic solution or metal ion having a different composition ratio from the electrolytic solution is supplied to the lower space 21b. The supply mode of the electrolytic treatment liquid may be changed such that the electrolytic solution not containing is supplied.
The container 16a may be mounted so that the surface 3a of the rotating cathode body 3 and the end portion 19b of the porous plate body 19 are in sliding contact with each other, and a slight clearance is formed between the surface 3a and the porous plate body 19. It may be mounted as described above.

However, in the case of the former mounting mode, plate-like or annular end portions 3b made of an insulating material are attached to both ends of the surface 3a of the rotating cathode body 3, and the end portions 3b and the porous plate body are attached. A slight clearance is formed between the other portion of the perforated plate body 19 and the surface 3a of the rotating cathode body so that the end portions of 19 slidably contact each other. Alternatively, the wear resistance, lubricity, and
For example, foamed plastic such as foamed polyethylene having a high elasticity may be attached.

In the latter case, the electrolytic treatment liquid ejected from the holes 19a forms a liquid film of the electrolytic treatment liquid having a uniform thickness on the surface 3a of the rotating cathode body, which corresponds to the clearance. 5 and FIG. 6, which is a cross-sectional view taken along the line VI-VI of FIG. 5, are views showing a state in which still another device example of the present invention is mounted on the surface of the rotating cathode body.

In this device 22, the electrolytic treatment liquid holding portion 23 is an elongated closed container having a convex lens cross section. That is, in this closed container 23, the mounting portion 23b of the counter electrode body 17 for anodic oxidation is liquid-tightly mounted on the back portion of the curved curved plate 23a, and both end portions 23 in the longitudinal direction are formed.
c and 23d are sealed, an electrolytic treatment liquid supply pipe 24 is attached to a substantially central position of the container, and an electrolytic treatment liquid jetting means 23e is formed at the tip of the curved plate 23a. An electrolytic treatment liquid supply means is configured to the surface 3a of the rotating cathode body 3. The ejection means 23e described above
Examples thereof include a plurality of holes formed along the longitudinal direction of the curved plate 23a, slits formed in the longitudinal direction of the curved plate 23a with a predetermined width, and the like.

The counter electrode body 17 is disposed in the counter electrode body mounting portion 23b, and the entire container has the rotating cathode body 3 in its longitudinal direction.
And the ejection means 23e formed on the curved plate 23a thereof are arranged so as to face the surface 3a of the rotating cathode body 3 at a predetermined interval. The electrolytically treated liquid, which has been fed into the container 23 from the supply pipe 24 by pumping up or the like, jets from the jetting means 23e after filling the container 23, and then onto the surface 3a of the rotating cathode body 3 rotating in the direction of arrow p. By being blown and flowing down along the surface 3a, a liquid film having a uniform thickness is formed there.

As the electrolytic treatment solution, the electrolytic solution used for producing the metal thin film may be used as it is, but if necessary, other electrolytic solution, for example, dilute sulfuric acid aqueous solution may be used. Good. While maintaining this state, the rotating cathode body 3 is used as an anode and the counter electrode body 17 is used as a cathode, and a predetermined voltage is applied between both electrodes, whereby the surface 3a of the rotating cathode body is anodized. The rotating cathode body 3 is indicated by the arrow p in the figure.
Since it rotates in the direction, the anodized film is formed on the surface 3a continuously or intermittently.

In the apparatus of this embodiment, the surface of the rotating cathode facing the surface 3a is a curved surface, but the shape is not limited to this, and the electrolytic treatment solution filled inside the rotating cathode is used. Any shape is acceptable as long as it can be ejected toward the surface 3a of the body. In addition, inside the container 23,
A means for uniformly dispersing the electrolytic treatment liquid, for example, a means for forming uniform small holes in the pipe, supplying the electrolytic treatment liquid to the pipe, and ejecting the electrolytic treatment liquid from the small holes may be provided. Furthermore, the position where the supply pipe 24 is attached does not have to be the central position of the device 22, and may be any position as long as the electrolytic treatment liquid can be uniformly ejected from the ejection means 23e.

A metal powder removing filter similar to that described above is provided between the counter electrode body 17 and the jetting means 23e so that the metal powder electrodeposited on the counter electrode body does not flow out to the surface 3a of the rotating cathode body 3. You may do it. In the apparatus of this embodiment, when an electrolytic solution for producing a metal foil having a relatively high metal concentration is used as the electrolytic treatment solution for anodization, the ejection port of the ejection unit 23e is made as small as possible, thereby reducing the amount of the electrolytic solution used. It is possible to reduce the amount of the electrolytic solution, and to reduce the scattering amount of the electrolytic solution, thereby suppressing the precipitation of the metal salt in the electrolytic solution used as much as possible.

For example, when an electrolytic copper foil is manufactured, a copper sulfate solution having a relatively high copper concentration is used as an electrolytic solution, but when the electrolytic solution is used as an electrolytic treatment solution for anodization, the temperature is low. In that case, crystals of copper sulfate may be generated and adhere to the device or the copper foil, which may hinder the smooth operation of the device. Therefore, in the apparatus of the embodiment shown in FIGS. 5 and 6, the shape of the ejection means 23e and the surface 3a of the cathode body 3a.
The inconveniences described above can be easily eliminated by simply changing the distance between the and.

[0052]

【Example】

Example 1 In the electrolytic copper foil manufacturing apparatus shown in FIG. 2, the rotating cathode body 3 was a titanium drum having a diameter of 3000 mm and a length of 1500 mm. Then, the surface of this drum was buffed.

Then, as shown in FIG.
mm, 1500 mm long stainless steel pipe 13 is coated with a polyester felt 14 having a thickness of 10 mm, and the polyester felt 14 is brought into contact with the polishing surface 3a of the titanium drum 3 to have a diameter above the polyester felt 14. A pipe 15 made of polyvinyl chloride having a diameter of 30 mm having 2 mm openings 15b formed at intervals of 10 mm was arranged.

An aqueous sulfuric acid solution having a concentration of 10 g / l (liquid temperature 50 ° C.) was supplied to the pipe 15 as an electrolytic treatment liquid for anodization, and was made to flow down to the polyester felt 14 through the opening 15b, while rotating the titanium drum 3. Terminals 13a, 1
The electrolytic voltage between the drum 3a and the titanium drum 3 is kept constant at 2V, and the anodic oxidation treatment for three rotations of the drum is performed so that an oxide film having a thickness of approximately 28Å is obtained (total treatment time is 3
Second).

The surface of the titanium drum 3 was uniformly discolored to a relatively light gold color, and it was confirmed that an anodized film made of titanium oxide was formed on the drum surface. Then, the electrolytic voltage was kept constant at 0.5 V, and anodizing treatment was continuously performed.
Then, the surface 3a of the titanium drum 3 is sequentially rotated toward the electrolytic apparatus of FIG. 2, where Cu: 80 g / l,
_{H 2 SO 4: 80g / l} , made glue 2 ppm, the liquid electrolyte used in the temperature 55 ° C., a current density of 50A / dm ^2, the thin copper layer by electrolytic deposition of copper on the surface 3a under the conditions of a flow rate 2m / sec Was formed, and then peeled from the surface 3a of the titanium drum 3, and the electrolytic copper foil 7 having a thickness of 18 μm was continuously manufactured while continuing the above-mentioned continuous anodizing treatment of 0.5 V. .

This work was continued for 15 days, during which
It was not necessary to perform buffing once. The tensile strength (kg / mm ² ), elongation (%), roughness (Rz) of the shiny surface, and folding strength (times) of the obtained electrolytic copper foil were measured. The results are shown in Table 1. For comparison, the titanium drum was not subjected to anodizing treatment, but was buffed in a cycle of 24 hours, and the characteristics of the obtained electrolytic copper foil were measured (Comparative Example 1). The results are also shown in Table 1.

The thickness of the anodized film was measured using an Auger spectroscopic analyzer. According to this measurement method,
It has been confirmed that there is a relationship between the electrolytic voltage during anodic oxidation and the thickness of the formed anodic oxide film that a film having a thickness of about 14Å is formed per 1 V of the electrolytic voltage. Also in the following examples, the thickness of the anodized film is a value measured in the same manner as above.

[0058]

[Table 1] * 1: Based on JISC6511 * 2: JISC6
Compliant with 511 * 3: Compliant with JIS B0601 * 4: JISP8
Compliant with 115 As is clear from the data in Table 1, the electrolytic copper foil produced by the method of the present invention is superior in tensile strength to conventional ones and is useful as a copper foil for copper-clad laminates. is there.

In Example 1, the formation of the anodic oxide film is continuously carried out. However, the anodic oxidation is intermittently performed every 1 hour, 6 hours, and 12 hours for one revolution of the drum by using an automatic timer. The properties of the obtained electrolytic copper foil were the same as those of Example 1. In addition, as another comparative example, the electrolytic voltage at the time of anodization is 0.5 V (the thickness of the coating is 7
(Corresponding to Å) and a sulfuric acid aqueous solution having a concentration of 20 g / l was used to continuously produce an electrolytic copper foil in the same manner as in Example 1 (Comparative Example 2). In Comparative Example 2, it was necessary to buff the drum 7 days after the start of the work.

Next, the influence of the thickness of the anodized film on the characteristics of the copper foil was examined. In Example 1, the electrolytic voltage during the initial formation of the anodic oxide film was changed to form anodic oxide films having different thicknesses on the drum surface. In each case, the thickness was 18 μm under the same conditions as in Example 1.
m electrolytic copper foil was continuously manufactured. The tensile strength (kg / mm ² ), elongation (%), roughness of the shiny surface (Rz), and the number of pinholes per 10 m ^{2 of} copper foil area of each obtained electrolytic copper foil were measured. The results are shown in FIG. 7 as a relationship with the initial thickness of the anodized film.

As is clear from FIG. 7, when the initial thickness of the anodized film is thicker than 140Å, the obtained electrolytic copper foil has a low tensile strength and a low elongation, and pinholes are more likely to occur.

Example 2 Instead of the stainless steel pipe 13, a poly having a diameter of 200 mm was used.
68 μm thick copper foil is attached to the outer circumference of the vinyl chloride pipe
Used electrolytic solution, electrolytic treatment liquid 1 for anodic oxidation
5a is an aqueous solution of sulfuric acid having a concentration of 1 g / l (liquid temperature 60 ° C.)
That is, the diameter of the opening 15b of the pipe 15 was 2.5 mm.
That is, the anodic oxidation treatment for 3 rotations of the drum (total treatment time
The electrolysis voltage at the time of 6 seconds is a constant value of 5 V (of the anodized film)
The thickness was equivalent to about 70Å), the electrolytic solution for copper electrodeposition
Is Cu: 100 g / l, H₂SO _Four: 100 g / l, d
It consisted of 3 ppm of water, the liquid temperature was 60 ° C, electrolysis
The condition is a current density of 60 A / dm², The flow rate is 2m / sec
Except for the above, the anodizing treatment was performed in the same manner as in Example 1.
While keeping the electrolysis voltage at a constant value of 0.5 V, the thickness of 3
A 5 μm electrolytic copper foil was continuously manufactured.

This work was continued for one month,
There was no need to buff once. The tensile strength (kg / mm ² ), elongation (%), roughness (Rz) of the shiny surface, and folding strength (times) of the obtained electrolytic copper foil were measured. The results are shown in Table 2.

For comparison, the titanium drum was subjected to buffing at a cycle of 40 hours without anodizing.
The characteristics of the obtained electrolytic copper foil were measured (Comparative Example 3). Further, as another comparative example, an electrolytic copper having a thickness of 35 μm was prepared in the same manner as in Example 2 except that the electrolytic voltage was 15 V at the time of anodization at a constant value (corresponding to a thickness of about 210 Å of the anodized film). A foil was produced continuously (Comparative Example 4). These results are also shown in Table 2.

[0065]

[Table 2] As is clear from the data in Table 2, the electrolytic copper foil produced under the conditions of Example 2 also has superior tensile strength as compared with the conventional one, and is useful as a copper foil for copper-clad laminates. .

In Example 2, the formation of the anodic oxide film is continuously carried out. However, 0.5 V anodic oxidation is performed by using an automatic timer for every 12 hours and 24 hours per drum revolution. Although it was carried out intermittently, the properties of the obtained electrolytic copper foil were similar to those of Example 2.

Example 3 In the apparatus of FIG. 3, the polyvinyl chloride pipe 13 had a diameter of 150 mm, the opening 15b of the pipe 15 had a diameter of 1.5 mm, and the anodization of three rotations of the initial drum was performed. Electrolysis voltage is 10V during treatment (total treatment time is 12 seconds)
Was constant (the thickness of the anodized film was equivalent to about 140Å), and the electrolytic conditions during copper electrodeposition were current density 7
Except that the flow rate was 0 A / dm ² and the flow rate was 3 m / sec,
Under the same conditions as in Example 2, an electrolytic copper foil having a thickness of 70 μm was continuously manufactured.

This work was continued for one month,
There was no need to buff once. The tensile strength (kg / mm ² ), elongation (%), roughness (Rz) of the shiny surface, and folding strength (times) of the obtained electrolytic copper foil were measured. The results are shown in Table 3. For comparison, the titanium drum was not subjected to anodizing treatment, but was buffed in a cycle of 50 hours, and the characteristics of the obtained electrolytic copper foil were measured (Comparative Example 5). The results are also shown in Table 3.

[0069]

[Table 3] As is clear from the data in Table 3, the electrolytic copper foil manufactured under the conditions of Example 3 also has superior tensile strength as compared with the conventional one, and is useful as a copper foil for copper-clad laminates. .

In Example 3, the formation of the anodic oxide film is continuously performed. However, after the anodic oxidation for 3 rotations of the drum is performed at 10 V, the anodic oxidation of 1 V is performed by using the automatic timer. The performance was intermittently performed for one round of the drum every 12 hours and 24 hours, and the properties of the obtained electrolytic copper foil were the same as those of Example 3.

As another comparative example, the sulfuric acid aqueous solution used in Example 3 was filled in an electrolytic bath different from the electrolytic bath for producing electrolytic copper foil, and a drum whose surface was buffed was immersed in the electrolytic bath for electrolysis. Anodizing treatment was performed at a constant value of voltage 10V. The treated drum was set in an electrolytic bath for producing an electrolytic copper foil, and an electrolytic copper foil was continuously produced in the same manner as in Example 3 (Comparative Example 6). In the case of Example 3, the anodizing treatment-manufacturing of the electrolytic copper foil can be continuously carried out, but the above-mentioned Comparative Example 6
In this case, the copper foil production had to be interrupted for 24 hours in order to move the treated drum to an electrolytic bath for producing electrolytic copper foil.

Example 4 In the anodized film forming apparatus of Example 1, the pipe 15 was used.
The opening 15b has a diameter of 3 mm, and the electrolytic voltage during operation is constant at 1 V (the thickness of the anodized film is equivalent to about 14 Å)
Then, the surface 3a of the cathode drum 3 was continuously oxidized for 4 rotations (total treatment time was 2.5 seconds), and the electrolysis conditions during copper electrodeposition were the same as in Example 3. In the same manner as in Example 1, set the electrolytic voltage of the anodizing treatment to 0.1 V.
While continuing the anodizing treatment while maintaining a constant value of, an electrolytic copper foil having a thickness of 12 μm was continuously manufactured.

This work was continued for 1 week, during which 1
There was no need to buff again. The tensile strength (kg / mm ² ), elongation (%), roughness (Rz) of the shiny surface, and folding strength (times) of the obtained electrolytic copper foil were measured. The results are shown in Table 4. For comparison, buffing is performed in a 24-hour cycle without anodizing the titanium drum,
The characteristics of the obtained electrolytic copper foil were measured (Comparative Example 7). The results are also shown in Table 4 as Comparative Example 7.

In another anodic oxidation treatment tank, an electrolytic voltage of 1
An anodized film is previously formed on the surface by performing anodization treatment of V, and this titanium drum is set on a copper foil production line to produce an electrolytic copper foil having a thickness of 12 μm under the same conditions as in Example 4. did. After the operation for about 3 hours, the peeling property of the electrolytic copper foil was deteriorated, the peeling tension of the electrolytic copper foil was partially non-uniform, and wrinkles were observed in the obtained electrolytic copper foil. Therefore, it became necessary to remove the drum from the line and perform anodizing treatment on the drum surface again.

As described above, when the anodizing treatment is performed outside the line in advance, the anodizing treatment must be performed every 3 hours, and therefore, the length of the electrolytic copper foil manufactured by one continuous operation is long. Since the length is at most about 600 m, it is not possible to continuously manufacture a long product, and not only workability but also productivity is deteriorated. The characteristics of the obtained electrolytic copper foil are also shown in Table 4 as Comparative Example 8.

[0076]

[Table 4]

Example 5 The porous plate member 19 was attached to the surface 3a of the titanium drum 3 which was buffed by using the anodized film forming apparatus shown in FIG.
It was attached so that the clearance between the surface and the surface 3a was 1 mm. The counter electrode 17 is a stainless steel plate, and the metal powder removal filter 20 is a microporous film in which fine pores having a pore diameter of 1 μm are distributed.

The electrolytic solution used in Example 1 is supplied to the supply pipe 18c.
Is supplied to the upper space 21a as an electrolytically treated liquid from the above, and then is discharged from the discharge pipe 18b and refluxed again to the electrolytic cell,
Further, the electrolytic solution via the filter was supplied from the supply pipe 18a to the lower space 21b and ejected from the hole 19a of the perforated plate 19 to the surface 3a of the rotating cathode body to form a liquid film of the electrolytic solution there.

In this state, the electrolytic voltage between the titanium drum 3 and the stainless steel plate (counter electrode) 17 was kept constant at 2 V, and anodization treatment was performed so that an anodized film with a thickness of about 28 Å was obtained. Subsequently, an electrolytic copper foil having a thickness of 35 μm was formed on the anodized film under the same conditions as in Example 1. This work was continued for one month, but during that time, it was not necessary to perform buffing once.

Tensile strength (kg / mm ² ) of the obtained electrolytic copper foil,
The elongation (%), the roughness of the shiny surface (Rz), and the folding endurance (times) were measured. The results are shown in Table 5. For comparison, the titanium drum was not anodized and
Buffing was performed in an 8-hour cycle, and the characteristics of the obtained electrolytic copper foil were measured (Comparative Example 9). The results are also shown in Table 5.

[0081]

[Table 5]

Example 6 In the apparatus of Example 5, an anion exchange resin membrane (high temperature type AMH manufactured by Tokuyama Soda Co., Ltd.) was used as the metal powder removing filter 20 and the end portion 19b of the porous plate 19 was used. A flexible foamed polyethylene sheet was interposed between the surface 3a of the titanium drum and the device 16 and the surface 3a of the titanium drum were brought into sliding contact with each other.

Almost no leakage of the supplied electrolytic solution occurred, and the electrolytic solution could be effectively used. Upper space 21a
1 g / l of a sulfuric acid aqueous solution is circulated and supplied from a supply pipe 18c by a pump, and the lower space 21b is an electrolytic solution for producing an electrolytic copper foil, Cu: 100 g / l, H ₂ S.
O _4: 90g / l, is made liquid temperature from glue 4ppm 65
The electrolytic solution at ℃ is supplied from the supply pipe 18a, the electrolytic voltage between the titanium drum 3 and the stainless steel plate 17 is kept constant at 5 V, and anodization is performed so that an oxide film with a thickness of about 70 Å is obtained. Then, on this anodized film,
Using the above electrolytic solution, current density 50 A / dm ² , flow rate 1 m /
An electrolytic copper foil having a thickness of 35 μm was formed under the condition of sec.

The surface 3a of the titanium drum was subjected to anodizing treatment for 2 rotations of the drum (total treatment time was 4 seconds), and then electrolytic copper foil was continuously produced for about 15 days.
During that time, it was not necessary to perform buffing once. The tensile strength (kg / mm ² ), elongation (%), roughness (Rz) of the shiny surface, and folding strength (times) of the obtained electrolytic copper foil were measured.
The results are shown in Table 6.

For comparison, the titanium drum was subjected to buffing at a cycle of 48 hours without anodizing.
The characteristics of the obtained electrolytic copper foil were measured (Comparative Example 1).
0). The results are also shown in Table 6.

[0086]

[Table 6]

Example 7 A heat-resistant polyvinyl chloride material was used, and the overall shape was 15
5 and 6, a slit 23e having a width of 2 mm and a length of 1400 mm is formed in the longitudinal direction at the tip of the curved plate 23a having a length of 00 mm, a width of 200 mm, and a thickness of 100 mm, and a supply pipe 27 having a diameter of 25 mm is attached. The sealed container 23 shown in was manufactured. Inside this container 23, a length of 1400 mm and a width of 10
A copper plate having a thickness of 0 mm and a thickness of 1 mm is arranged as the counter electrode 17.

This container 23 was mounted on a titanium drum 3 having the same size and shape as in Example 1 and having its surface buffed, with its slit 23e facing the drum surface. The electrolytic solution used in Example 1 was supplied from the supply pipe 24 into the container 23 to fill the same, and then was jetted from the slit 23e to the surface 3a of the titanium drum 3 to form a liquid film of the electrolytic solution there. .

In this state, the electrolytic voltage was kept at 5 V by the stabilized DC power supply, and while performing the anodic oxidation treatment for two rotations of the titanium drum (total treatment time was 8 seconds), the thickness was 68 μm.
After manufacturing the electrolytic copper foil of m for 24 hours, anodizing treatment with an electrolytic voltage of 2V is performed for 3 rotations (total processing time is 12 seconds), and then, while keeping the electrolytic voltage constant at 0.5V,
An electrolytic copper foil having a thickness of 18 μm was manufactured under the same conditions as in Example 1. This operation was continued for 2 weeks, but during that time, it was not necessary to perform buffing once. The obtained copper foil also had the same performance as in Example 1.

[0090]

As is clear from the above description, the anodic oxide film formed on the surface of the cathode body by the method of the present invention functions as a protective film having a uniform and excellent corrosion resistance. Therefore, during the production of the metal foil, it is possible to effectively prevent the surface defects of the metal foil and the texture defects such as pinholes which are caused by the non-uniform oxide film formation on the surface of the cathode body, and it is possible to produce a good quality metal foil. it can.

Further, it is not necessary to perform buffing on the surface of the cathode body in a short period as in the conventional case, the material cost and work cost involved in the buffing work are reduced, and the wear of the cathode body itself is reduced, so that the service life is shortened. Therefore, the frequency of replacement of the cathode body is reduced, and the productivity of the metal foil can be significantly increased. Further, as shown in Examples 1 to 4, when the cathode body is a rotating drum and the counter electrode body of the anodized film forming apparatus is a conductive roll, this conductive roll responds to the rotation of the rotating drum. Since it can be automatically rotated, it is not necessary to attach a driving means.

In the case of the anodized film forming apparatus used in Examples 5 to 6, an electrolytic solution having a relatively high metal ion concentration for producing a metal foil can be used as the electrolytic treatment solution. And even if the electrolytic solution is mixed in the electrolytic bath for metal foil production, the same solution does not cause any inconvenient problems.
There is no need to install a special liquid mixture prevention device. Furthermore, it is not necessary to separately prepare an electrolytic treatment liquid for forming the anodized film, and the electrolytic treatment liquid can be directly taken out from the electrolytic cell and used. Also, by interposing an ion exchange membrane as a metal powder removal filter between the counter electrode and the surface of the cathode body, it is possible to prevent the situation where metal is electrodeposited on the counter electrode, and when a conductive roll is used. Similarly, it is possible to prevent the movement of the metal powder generated in the counter electrode to the cathode body, which adversely affects the production of the metal foil.

Further, in the case of the apparatus used in Example 7, even if the electrolytic treatment solution for anodic oxidation is the electrolytic solution used for the production of the metal foil, the width of the slit is narrowed to reduce the ejection amount. The area of the cathode body to be ejected can be minimized and reduced. Therefore, it is possible to prevent a situation where the metal salt does not deposit from the electrolytic solution on the surface of the insulator or the like at the end portion or the peripheral edge of the cathode body, and the metal salt adheres to the obtained metal foil.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a conventional metal foil manufacturing apparatus.

FIG. 2 is a cross-sectional view showing an example of a metal foil manufacturing apparatus equipped with the anodized film forming apparatus of the present invention.

FIG. 3 is a cutaway perspective view showing an example of an anodized film forming apparatus of the present invention.

FIG. 4 is a partially cutaway perspective view showing another example of the anodized film forming apparatus of the present invention.

FIG. 5 is a partially cutaway perspective view showing still another example of the anodized film forming apparatus of the present invention.

6 is a sectional view taken along line VI-VI in FIG.

FIG. 7 is a graph showing the relationship between the thickness of an anodized film and the characteristics of copper foil.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Electrolyte tank 2 Anode body 3 Rotating cathode body 3a Surface of the rotating cathode body 3b 3 End part of the rotating cathode body 3 Gap 5 Electrolyte solution 6 Distributor (electrolyte solution outlet) 7 Metal foil 8a, 8b Guide roller 9 Winder DESCRIPTION OF SYMBOLS 10 Buff 11 Anodized film forming apparatus of the present invention 12 Shaft 13 Conductive roll (counter electrode) 13a Conductive roll terminal 14 Felt (electrolytic treatment liquid holding part) 15 Pipe (electrolytic treatment liquid supply means) 15a Electrolytic treatment liquid 15b Opening 15c Pump 16 Another anodized film forming apparatus of the present invention 16a Container (electrolytic treatment liquid holding part) 17 Counter electrode 18 Electrolytic treatment liquid supply means 18a Electrolytic treatment liquid supply pipe 18b Electrolytic treatment liquid discharge pipe 18c Electrolytic treatment liquid supply pipe 19 Perforated Plate 19a Hole for Ejection of Electrolytic Treatment Liquid 19b End of Perforated Plate 19 20 Metal Powder Removal File 21a Upper space 21b Lower space 22 Still another anodic oxide film forming apparatus 23 of the present invention 23 Sealed container (electrolytic treatment solution holding part) 23a Curved plate 23b Mounting part (of counter electrode) 23c, 23d Both ends 23e of sealed container 23 Ejection means 24 Electrolyte supply pipe

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Ashizawa 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd.

Claims (10)

[Claims] 1. A thin metal layer is formed by applying an electric current between an anode body and a cathode body which are immersed in an electrolytic solution to cause an electrolytic reaction, and depositing a metal on the surface of the cathode body by the electrolytic reaction. After that, when the metal thin layer is peeled from the surface of the cathode body to continuously produce a metal foil, the surface of the cathode body exposed after peeling the metal thin layer is continuously or intermittently exposed. A method for producing a metal foil, which comprises electrolytically oxidizing and forming an anodized film on the exposed surface. 2. The method for producing a metal foil according to claim 1, wherein the metal foil is a copper foil. 3. The electrolytic oxidation is performed at an electrolytic voltage of 0.1 to 10 V.
The method for producing a metal foil according to claim 1, which is performed by the constant voltage method. 4. The thickness of the anodized film is 1.4 to 14
The method for producing a metal foil according to claim 1, wherein the metal foil is 0Å. 5. The electrolytic treatment liquid used during the electrolytic oxidation is
The method for producing a metal foil according to claim 1, wherein the electrolytic solution for producing a metal foil or the same component as the electrolyte has a different component ratio. 6. The method for producing a metal foil according to claim 5, wherein the temperature of the electrolytic treatment liquid is higher than the deposition temperature of the electrolyte dissolved in the electrolytic treatment liquid. 7. The electrolytic treatment liquid used in the electrolytic oxidation is
The method for producing a metal foil according to claim 1, which is an electrolytic solution containing no metal ion to be electrodeposited on the surface of the cathode body. 8. The method for producing a metal foil according to claim 1, wherein the metal foil is a copper foil, and the electrolytic treatment liquid used in the electrolytic oxidation is a sulfuric acid aqueous solution having a concentration of 10 g / l or less. 9. The method for producing a metal foil according to claim 1, wherein at least the surface of the cathode body is made of titanium or a titanium alloy. 10. The method for producing a metal foil according to claim 1, wherein the cathode body has a drum shape.