JP2020033613A - Electrode for electrolytic plating - Google Patents

Abstract

To provide an electrode for an electrolytic plating that suppresses the depletion of catalyst.SOLUTION: An electrode 100 used for an electrolytic plating comprises: an electrode base material 10; a catalyst layer 30 arranged on the electrode base material; and a protective layer 50 arranged on the catalyst layer. In the electrode, a surface area of the electrode having the protective layer is relatively smaller than a surface area of the electrode having no protective layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrode for electrolytic plating. More specifically, the present invention relates to an electrode used for electrolysis in a plating method.

  Electroplating has been widely used industrially since before. For example, a technique for manufacturing a metal foil by electrolytic plating is known. Such electrolytic plating may be referred to as electroforming (especially "electroforming"). Electroforming can obtain metal foil continuously and relatively easily, and it is relatively easy to control metal foil characteristics such as surface smoothness, and is often used in the production of metal foil such as copper foil. I have.

  The production of metal foil by the electrolytic plating method utilizes the principle of electroplating, and uses electrodes. For example, as shown in FIG. 8, an electrode 520 immersed in an electrolytic solution 510 of an electrolytic cell 500 and a drum-shaped counter electrode 530 forming a pair with the electrode 520 are used. The electrode 520 for electrolytic plating is provided so as to face the counter electrode 530 having a drum shape. When a current is applied between the electrode 520 for electrolytic plating and the drum-shaped counter electrode 530, a metal component can be electrolytically deposited on the surface of the counter electrode 530. Therefore, the metal foil 550 is continuously obtained by conducting electricity while rotating the drum-shaped counter electrode 530 with respect to the electrode 520 and sequentially peeling the metal layer formed due to electrolytic deposition from the counter electrode 530. Can be.

Japanese Patent Publication No. 6-47758 Japanese Patent No. 3278492 JP 2006-503364 A Japanese Patent No. 3832645

  The inventor of the present application has noticed that there is still a problem to be overcome in a conventional electrode used for electrolytic plating, and has found that it is necessary to take measures for that. Specifically, the present inventor has found that there are the following problems.

  In the production of a metal foil by an electrolytic plating method, an insoluble electrode is generally used as an electrode facing a drum-shaped electrode. In particular, an insoluble anode placed opposite to a drum-shaped cathode is used. The reaction at such an insoluble anode generally involves an oxidation reaction of water, that is, an oxygen evolution reaction. However, although a chlorine generation reaction may occur depending on the components of the electrolytic solution, an oxygen generation reaction is a main reaction. Therefore, a catalyst having high activity against oxygen generation is often used for such an electrode for electrolytic plating.

  On the other hand, additives are often added to an electrolytic solution used for producing a metal foil by an electrolytic plating method. For example, additives may be added from the viewpoint of the surface smoothness and / or glossiness of the electrolytic metal foil. While such additives are desirable for obtaining the desired metal foil, they may not always be desirable for electrodes with catalyst.

  Specifically, it has been found that, depending on an additive contained in an electrolytic solution for producing a metal foil by an electroplating method, it contributes to promoting catalyst consumption, and the electrode catalyst is reduced with the production of the metal foil ( (See FIG. 7).

  The present invention has been made in view of such circumstances. That is, a main object of the present invention is to provide an electrode for electrolytic plating in which catalyst consumption is suppressed.

  The inventor of the present application has attempted to solve the above-described problem by responding in a new direction, not on an extension of the conventional technology. As a result, the inventors have arrived at the invention of an electrode for electrolytic plating in which the above main object has been achieved.

In the present invention, the electrode for electrolytic plating,
Electrode substrate,
Comprising a catalyst layer provided on the electrode substrate, and a protective layer provided on the catalyst layer,
An electrode for electrolytic plating is provided, wherein the surface area of the electrode having the protective layer is relatively smaller than the surface area of the electrode having no protective layer.

  The electrode of the present invention is an electrode for electrolytic plating in which catalyst consumption is suppressed.

  Specifically, in the electrode of the present invention, the surface area of the electrode having the protective layer has a relatively small surface area as compared with the surface area of the electrode having no protective layer. Effectively suppressed.

FIG. 2 is a schematic cross-sectional view showing a laminated structure of an electrode for electrolytic plating of the present invention. Schematic diagram and principle formula for explaining cyclic voltammetry Schematic cross-sectional view for explaining “electrode laminated structure having intermediate layer” Graph showing the results of "relative comparison of catalyst consumption rates" Cyclic voltammogram obtained in "Confirmation test of protective layer characteristics" Graph showing the result (relative ratio of surface area) of “Confirmation test of protective layer characteristics” Schematic cross-sectional view showing that the amount of the electrode catalyst is reduced with the production of the electrolytic metal foil Schematic cross-sectional view for illustrating an embodiment of manufacturing a continuous metal foil by electrolytic plating

  Hereinafter, the electrode for electrolytic plating according to the present invention will be described in detail. Although description will be made with reference to the drawings as necessary, the contents shown are merely schematic and exemplary for understanding the present invention, and the appearance, dimensional ratio, and the like may be different from the real ones.

  “Cross sectional view” used directly or indirectly in describing the present invention corresponds to a cross sectional view cut along the thickness direction of the electrode, and substantially corresponds to a figure in which an object is viewed from the side. To put it simply, the “cross-sectional view” may correspond to a diagram when viewed in a form as shown in FIG. 1 and the like. In addition, directional matters such as “up” and “down” used directly or indirectly in connection with the electrode for electrolytic plating are also based on the form as shown in FIG. .

  The various numerical ranges referred to in this specification are intended to include the lower and upper limit values themselves, unless specifically stated otherwise. That is, for example, a numerical range such as 1 to 10 can be interpreted as including the lower limit value “1” and the upper limit value “10” unless otherwise specified.

《Electrode of the present invention》
The electrode of the present invention is an electrode used for electrolytic plating. Electroplating is used, for example, for producing metal foil or the like, or used for rust prevention plating, steel plate plating, or the like. In particular, in the former case, it can be said that the electrode of the present invention is an electrode for producing an electrolytic metal foil. The term “electrolytic metal foil” as used herein refers to a metal foil manufactured by an electrolytic plating method. Examples of the electrolytic metal foil include a metal foil containing at least one selected from the group consisting of copper, nickel, and iron. As one typical example, the electrolytic metal foil is a copper foil (or a copper alloy foil).

  As shown in FIG. 1, the electrode 100 for electrolytic plating (for example, for producing an electrolytic metal foil) of the present invention is used so as to face a drum-shaped counter electrode 200. In a preferred metal foil production, the electrode 100 of the present invention corresponds to an “anode”, while the counter electrode 200 corresponds to a “cathode”. During production of an electrolytic metal foil, a current is passed between the anode and the cathode to form a metal foil (more precisely, a metal layer that is a precursor of the metal foil) on the cathode due to electrolytic deposition. Is done. The electrode 100 used as such an anode is preferably a so-called insoluble anode. In the case of an insoluble anode, the plating metal component is not supplied by dissolving the anode electrode, but the component originally contained in the electrolytic solution in the electrolytic cell becomes the supply source of the plating metal component.

  The counter electrode serving as a cathode has a drum shape as a whole and is provided rotatably. The “drum shape” here means that the counter electrode has a cylindrical shape or a substantially cylindrical shape that contributes to continuous production of metal foil. In use, the electrode of the present invention, which serves as an anode, is arranged so as to be separated from the drum-shaped cathode and surround a part thereof when used.

  The electrode for electrolytic plating of the present invention has a layered structure. In this regard, the electrode of the present invention has at least an electrode substrate, a catalyst layer, and a protective layer. Specifically, as shown in FIG. 1, a catalyst layer 30 is provided on an electrode substrate 10 forming a main body of the electrode, and a protection layer 50 is provided on the catalyst layer 30. As can be seen from the illustrated embodiment, in the electrode 100 of the present invention, the electrode substrate 10, the catalyst layer 30, and the protective layer 50 are provided so as to be stacked in layers.

  The electrode substrate 10 contributes to energization during electrolytic plating. For example, the electrode base material 10 contributes to energization during the production of an electrolytic metal foil, and is a portion that substantially functions as an anode during electroforming. The electrode substrate 10 forms a main body of the electrode 100 for electrolytic plating. The material of the electrode substrate 10 is not particularly limited, but may be a valve metal. More specifically, the electrode substrate may comprise at least one metal selected from the group consisting of tantalum, niobium, titanium, hafnium, zirconium, tungsten, bismuth and antimony. Although merely an example, the electrode base material 10 according to a preferred embodiment includes titanium or a titanium alloy from the viewpoint of corrosion resistance and / or versatility. The thickness (average thickness) of the electrode substrate is not particularly limited, but may be, for example, about 0.5 mm to 30 mm.

  In addition, regarding the “electrode substrate”, the electrode of the present invention may be a member that is separate from the electrolytic cell. This means that the electrode substrate and the electrolytic cell are separate from each other. In such a case, an electrode (for example, a plurality of plate-like electrodes) is attached to the electrolytic cell during electrolytic plating. Alternatively, the electrode of the present invention may have a form integrated with the electrolytic cell. This means that the electrolytic cell itself substantially forms the electrode substrate. This is merely an example, but in the case of “integration”, an electrolytic cell that is curved so as to face a drum-shaped counter electrode at a predetermined interval is used, and a catalyst layer and a protective layer are formed on the curved surface of the electrolytic cell. ing.

  The catalyst layer 30 is provided on the electrode substrate 10. Although another different layer may be interposed as an intermediate layer, the catalyst layer 30 may be provided directly on the surface of the electrode substrate 10. When the electrode 100 of the present invention is used as an insoluble anode when producing an electrolytic metal foil by an electrolytic plating method, the reaction of such an electrode is mainly an oxygen generation reaction. Therefore, a catalyst component having high activity for generating oxygen may be included in the catalyst layer 30. For example, a catalyst comprising a platinum group metal or an oxide thereof may be coated. That is, the catalyst layer 30 provided on the electrode substrate 10 is formed of at least one platinum group metal selected from the group consisting of iridium, ruthenium, platinum, palladium, rhodium and osmium, and / or oxidation of the platinum group metal. It may comprise at least an object. The catalyst layer 30 may include a metal component other than the platinum group metal and / or its oxide, and may additionally include, for example, a metal component of a Group 5 element. By way of example only, in an electrode of the present invention according to a preferred embodiment, the catalyst layer 30 comprises iridium (Ir) or such that it comprises tantalum (Ta). It may be. The thickness (average thickness) of the catalyst layer is not particularly limited, but may be, for example, about 1 μm to 20 μm.

  The protection layer 50 is provided on the catalyst layer 30. Preferably, the protective layer 50 is provided directly on the surface of the catalyst layer 30 of the electrode substrate 10. As shown in FIG. 1, it is preferable that the catalyst layer 30 does not come into direct contact with the electrolytic solution due to the presence of the protective layer 50. The protective layer 50 provided in the electrode of the present invention mainly corresponds to a layer for protecting the catalyst layer 30. In other words, the term "protective layer" as used in the present specification broadly refers to a layer that protects a catalyst used for an electrode for producing an electrolytic metal foil by electrolytic plating, and in a narrow sense, electrolytic plating. It refers to a layer that protects the electrode catalyst (particularly the anode catalyst) from additives contained in the electrolytic solution for producing an electrolytic metal foil by the method.

  An additive for improving the characteristics of a metal foil to be produced is usually added to an electrolytic solution for producing an electrolytic metal foil by an electrolytic plating method. For example, when a copper foil used for a printed circuit material and / or a current collector of a battery is manufactured by electroforming, an additive is added to the electrolytic solution from the viewpoint of improving the surface smoothness and / or glossiness of the copper foil. Is often added. That is, additives are often added to the electrolyte containing the aqueous solution of copper sulfate in view of improving the properties such as surface smoothness and / or gloss of the obtained electrolytic copper foil. By way of example only, such additives may include at least one selected from the group consisting of saccharin, gelatin, glue, thiourea, and PEG. Although the additive is desirable to obtain a desired metal foil, it becomes a factor of promoting the consumption of the electrode catalyst, and the electrode catalyst layer (particularly, the catalyst layer included in the anode at the time of manufacturing the electrolytic metal foil) is considered over time. The inventor of the present application has found that the reduction of the amount is promoted. Therefore, in the electrode of the present invention, a protective layer is provided on the catalyst layer in order to suppress such an undesirable promotion of reduction.

  In the electrode 100 for electrolytic plating (for example, for producing an electrolytic metal foil) of the present invention, the protective layer 50 preferably contains a transition metal. That is, the protection layer 50 provided on the catalyst layer 30 preferably includes a transition element metal. This is because the protective layer 50 containing a transition metal suitably contributes to protection of the catalyst layer.

  Among the transition metals, metals of Group 5 elements are particularly preferable. That is, it is preferable that the protective layer 50 includes a metal of a Group 5 element. In other words, it can be said that the protective layer 50 provided on the catalyst layer 30 preferably contains a vanadium group metal. This is because such a protective layer 50 containing a vanadium group, that is, a group 5 element, suitably contributes to protection of the catalyst layer. For example, the protective layer 50 comprises tantalum (Ta), and in the electrode of the present invention according to a preferred embodiment, the protective layer 50 is formed only from tantalum (Ta) (that is, 100% Ta-containing). May be a protective layer having a ratio.

  In another aspect, the material of the protective layer 50 in the present invention is preferably different from the material of the electrode substrate 10. In the electrode of the present invention according to a preferred embodiment, the protective layer 50 is made of a material consisting of only tantalum (Ta) or a material consisting of a combination of tantalum (Ta) and iridium (Ir), while the electrode base material 10 is made of The material is made of titanium or a titanium alloy.

  Here, the present invention is unique in terms of the surface area of the electrode having the protective layer. Specifically, in the electrode for electrolytic plating of the present invention (for example, for producing an electrolytic metal foil), the surface area of the electrode having the protective layer is relatively smaller than the surface area of the electrode having no protective layer. Have. This is because, for an electrode for electrolytic plating (for example, for producing an electrolytic metal foil), when comparing the electrode surface having a protective layer with the electrode surface having no protective layer, the former has a smaller surface area than the latter. It means that it has become. This also means that the surface area of the electrode (particularly, the electrode top surface) is reduced by providing the protective layer.

Specifically, in a preferred embodiment, the surface area of the electrode having the protective layer is as small as about 20% to 90% of the surface area of the electrode having no protective layer. That is, the surface area _{S a} of the electrode having a protective layer satisfies the condition of _{0.2 × S b ≦ S a ≦} 0.9 × S b in relation to the surface area _{S b} of the electrode having no protective layer. In an electrode having a protective layer having such a surface area characteristic, a protective effect of the catalyst layer is suitably brought about, as will be shown in Examples described later. In this regard, the inventor of the present application has found in the course of earnestly studying an electrode for electrolytic plating that suppresses catalyst exhaustion that the surface area of the electrode having the protective layer is at least partially related to the factor of catalyst exhaustion (described below). See "Relative Comparison of Catalyst Depletion Rates" in Examples). In particular, it has been found that the surface area of the electrode having the protective layer that exhibits the effect of suppressing catalyst consumption is smaller than the surface area of the electrode having no protective layer. The catalyst depleted velocity V _a of the electrode with a relatively low surface area protective layer is made of, for example 20% to 90% of the catalyst depletion rate V _b of such not provided with the protective layer electrode. More specifically, the catalyst depleted velocity V _a of the "protective layer present", although may be the difference depending on the firing temperature and the protective layer components during the protective layer formation, catalyst exhaustion velocity V _b of the "no protective layer" obtained is 20% to 85%, for example 20% to 30% of _{V b,} 35% to 45% of _{V b,} 70% to 80% of _{V b,} or may be such as 75% to 85% of _{V b.}

In the present invention, the surface area of the electrode having the protective layer is preferably as small as about 20% to 90% of the surface area of the electrode having no protective layer. More preferably, the surface area of the electrode having the protective layer is protected. is smaller and 25% to 85% of the surface area of the electrode having no layers, therefore, 0 the surface area S _a of the electrode having a protective layer, in relation to the surface area S _b of the electrode having no protective layer. satisfies more preferably the conditions of _{25 × S b ≦ S a ≦} 0.85 × S b. Although may difference depending on the firing temperature and the protective layer components during the protective layer formation, in terms of the further example, the surface area S _a of the electrode having a protective layer in relation to the electrode surface area S _b having no protective layer 0. or has become a condition of _{25 × S b ≦ S a ≦} 0.35 × S b, or may be or has become a condition of _{0.75 × S b ≦ S a ≦} 0.85 × S b. In particular, the former means that by providing the protective layer, the electrode surface area is reduced to about 1/4 as compared with an electrode without the protective layer.

  The “relatively small surface area of the electrode having the protective layer” with respect to the electrode of the present invention may be obtained by an electrochemical measurement, and particularly, the surface area / ratio obtained through the capacitance measurement of the electric double layer. It may be a surface area. In this regard, the “relatively small surface area of the electrode with the protective layer” may be based on cyclic voltammetry (CV), and is therefore calculated on the basis of the cyclic voltammogram -It may be a specific surface area.

  In cyclic voltammetry, the electrode potential is swept, and the surface area is determined based on the capacitance determined through measurement of the response current (see FIG. 2). In the electrode of the present invention, the surface area of the electrode having the protective layer is protected. It is as small as about 20% to 90% of the surface area of the electrode having no layer. That is, it can be said that the electrode having the protective layer is about 20% to 90% smaller than the electrode having no protective layer in terms of the surface area and the specific surface area obtained based on the cyclic voltammetry.

The term “specific surface area based on cyclic voltammetry” as used in the present invention means “Basic Edition of Electrochemical Measurement Manual” (9th edition, Maruzen Co., Ltd., The Institute of Electrical Chemistry, pp. 37-44). It refers to the surface area obtained in the described CV measurement. More specifically, the “specific surface area based on cyclic voltammetry” in the present invention refers to a surface area obtained by using a measuring device of an automatic polarization system HSV-110 (Hokuto Denko Corporation). I have. The measurement procedure (evaluation method) and measurement conditions in such a measurement device will be described below in detail.

Measurement procedure (evaluation method)
(1) First, a measurement cell as shown in FIG. 2 is assembled.
(2) Next, the terminals of the HSV-110 are connected to the working electrode, the counter electrode, and the reference electrode.
(3) Perform pretreatment of the working electrode.
(4) Perform measurement at a predetermined scanning speed.

Measurement conditions and temperature during measurement: room temperature (about 25 ° C)
-Electrolyte solution: 0.5M sulfuric acid aqueous solution-Working electrode: Either the electrode of the invention ("electrode with protective layer") or the electrode for comparison ("electrode without protective layer") (electrolysis area 10mm x 10mm)
-Counter electrode: Platinum plate (25 mm x 25 mm)
・ Reference electrode: Silver-silver chloride electrode

Pretreatment conditions: A cycle of 0.5 to 1.0 V (vs. Ag / AgCl) is performed at a scanning speed of 100 mV / s for 10 cycles.

Measurement conditions: A cycle of 0.5 to 1.0 V (vs. Ag / AgCl) is performed at a scanning speed of 10 mV / s for 3 cycles.

Previously described in detail the surface area S _b of the electrode having no protective layer. The electrode having no protective layer which has such a surface area may be an electrode before the protective layer is formed. That is, the electrode used for the surface area measurement may be an electrode before the formation of the protective layer which is a precursor of the electrode of the present invention.

  As understood from the above description, the “electrode without a protective layer” in the present invention means an electrode that can be regarded as a configuration in which only the protective layer is removed from the electrode for electrolytic plating of the present invention. Therefore, in a preferred embodiment, the “electrode without a protective layer” is an electrode composed of an electrode substrate and a catalyst layer provided thereon, wherein the catalyst layer is provided as the outermost layer. Electrodes. Note that such an electrode may have a configuration having an “intermediate layer” to be described later. Therefore, an “electrode without a protective layer” has a catalyst layer as the outermost layer, The electrode may additionally have an intermediate layer between the electrode base material.

In the present invention, the surface area S _b of the electrode having no protective layer, electrodes for electrolytic plating (e.g., Daiso Engineering Co., MD-100 or MD-160) surface for convenience may be adopted for. Such an electrode (for example, MD-100 or MD-160), which is a commercially available electrode for electrolytic plating, may correspond to the precursor electrode in that it has a catalyst layer provided on an electrode substrate. Therefore, the surface area of the electrode may be regarded as “surface area S _b ” in the present invention.

  The electrode for electrolytic plating of the present invention can be embodied in various modes. For example, the following aspects are considered.

(Top coat protective layer)
In such an embodiment of the electrode, the protective layer has a form of a top coat. That is, the protective layer 50 forms the uppermost layer in the electrode 100 as shown in FIG. This means that the protective layer is in direct contact with the electrolytic solution during the production of the metal foil by the electrolytic plating method, and the protective action of the catalyst layer against the electrolytic solution is directly provided by the presence of such a protective layer. I have.

  Since it forms the uppermost layer, the protective layer is exposed, and no additional layers or the like are provided thereon. In the present invention, the electrode having such a protective layer is preferably as small as about 20% to 90% of the surface area of the electrode having no protective layer.

(Protective layer in thin film form)
In such an embodiment, the protective layer has a thin film form. That is, the layer for protecting the catalyst layer is not in a thick form, and can at least contribute to the weight reduction of the electrode for electrolytic plating.

  Specifically, the protective layer has an average thickness of, for example, 15 μm or less. Even with such a protective layer in the form of a thin film having a thickness of 15 μm or less, the electrode of the present invention can exert an effect of suppressing catalyst consumption during the production of an electrolytic metal foil. The average thickness of the protective layer is more preferably 10 μm or less, and further preferably 8 μm or less. On the other hand, the lower limit of the average thickness of the protective layer is, for example, 4 μm, and may be 3 μm, 2 μm, or 1 μm.

  The “average thickness of the protective layer” in the present specification refers to a cross-sectional view of the protective layer based on a micrograph / image such as an SEM image (for example, a cross-sectional image taken by model JSM-IT500HR manufactured by JEOL Ltd.). , Mean 10 points (arithmetic mean). It should be noted that such "average" thickness implications can be applied to other layers as well.

(Electrode lamination structure with intermediate layer)
In such an embodiment, the laminated structure of the electrodes additionally has an intermediate layer. Specifically, as shown in FIG. 3, the electrode 100 for producing an electrolytic metal foil further includes an intermediate layer 60 between the electrode substrate 10 and the catalyst layer 30.

  Although not particularly limited, the presence of the intermediate layer can provide the effect of improving the protective properties of the electrode substrate or improving the adhesion strength of the catalyst layer to the electrode substrate. As can be seen from the illustrated embodiment and the like, the “intermediate” of the “intermediate layer” is based on the fact that a layer is provided between the portion forming the base material of the electrode and the catalyst.

  Although it is only an example, the average thickness of the intermediate layer may be about 5 μm to 20 μm. The material of the intermediate layer may be tantalum or the like, and may further include titanium or the like.

(Composite component embodiment of protective layer)
In such an embodiment, the material of the protective layer is not a single material but consists of a plurality of components. As described above, the protective layer preferably includes a transition metal. However, at least two kinds of transition metals are included in the protective layer. This makes it easier for the protective layer to exhibit more suitable protective properties.

  In a preferred embodiment, the two metals are a metal of a platinum group element and a metal of an element other than the platinum group element. For example, it is a metal of a group 5 element and a metal of a platinum group element. That is, the protective layer contains both metals of the platinum group element and the other elements, and preferably contains both metal components of the platinum group element and the fifth group element. In such a case, preferably, the metal other than the platinum group is relatively more than the metal of the platinum group element. This is because metals other than the platinum group have low activity as an electrode catalyst and do not cause an electrochemical reaction. For example, the content of a metal other than the platinum group element (for example, a Group 5 element metal) in the protective layer is 50% by weight (not including 50% by weight) to 98% by weight, preferably 60% by weight to 98% by weight, Preferably it is 70% to 98% by weight, for example 80% to 98% by weight, whereas the content of platinum group metal is 2% to 50% by weight, preferably 2% to 40% by weight. And more preferably 2% to 30% by weight, such as 2% to 20% by weight.

  As the composite component included in the protective layer, the Group 5 element may be tantalum (Ta) and the platinum group element may be iridium (Ir). That is, it may be a combination of tantalum (Ta) as a Group 5 element and iridium (Ir) as a platinum group element, and the protective layer may be made of a composite component of such a transition metal. To give a more specific example, for example, for a protective layer mainly containing tantalum (Ta) and iridium (Ir), the content of the tantalum (Ta) component is 50% by weight (not including 50% by weight). To 98% by weight, preferably 60% to 98% by weight, more preferably 70% to 98% by weight, for example 80% to 98% by weight, while the content of the iridium (Ir) component is It may be 2% to 50% by weight, preferably 2% to 40% by weight, more preferably 2% to 30% by weight, for example 2% to 20% by weight.

  Hereinafter, for a better understanding of the present invention, “a method for manufacturing an electrode for electrolytic plating” and “a device for manufacturing an electrolytic metal foil using an electrode for electrolytic plating” will be described.

<< Method of manufacturing electrode for electrolytic plating >>
The electrode for electrolytic plating of the present invention can be obtained by forming a catalyst layer on an electrode substrate to obtain an electrode with a catalyst layer, and then providing a protective layer thereon.

  The catalyst layer may be formed by any method as long as it can be provided on the electrode substrate. As one example, the catalyst layer can be formed by firing. Specifically, the catalyst layer can be formed by applying a raw material liquid corresponding to the catalyst layer precursor to the electrode base material, drying the applied material, and then subjecting it to firing. Such application, drying, and baking can be performed in the same manner as in the formation of the protective layer described in detail below. In addition, the electrode with a catalyst layer may use a commercially available electrode for electrolytic plating (for example, for electrolytic metal foil) or the like, for example, an electrode number MD-100 or MD-160 manufactured by Daiso Engineering Co., Ltd. May be used.

  Next, a protective layer is formed. The protective layer may be formed by any method as long as it can be provided on the catalyst layer of the electrode. As one example, the protective layer can be formed by firing.

  Specifically, a protective layer can be formed by applying a raw material liquid corresponding to the protective layer precursor on the catalyst layer, drying the resultant, and then subjecting it to firing. The raw material liquid is at least an example, but at least includes a transition metal and a solvent such as an organic solvent and / or water that dissolves the transition metal. The transition metal is a metal of Group 5 element as described above, for example, tantalum (Ta). In addition, the transition metal of the raw material liquid may further include a metal of a platinum group element, for example, a combination of tantalum (Ta) and iridium (Ir). Examples of the organic solvent include, but are not limited to, methanol, ethanol, propanol (n-propyl alcohol, isopropyl alcohol), and butyl alcohol (n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, and tert-butyl). Alcohols such as alcohols); ketones such as methyl ethyl ketone and methyl isobutyl ketone (MIBK); terpenes including α-terpineol, β-terpineol and γ-terpineol; ethylene glycol monoalkyl ethers; ethylene glycol dialkyl ethers; Diethylene glycol monoalkyl ethers; diethylene glycol dialkyl ethers; ethylene glycol monoalkyl ether acetates; ethylene glycol dialkyl ether acetate Tates; diethylene glycol monoalkyl ether acetates; diethylene glycol dialkyl ether acetates; propylene glycol monoalkyl ethers; propylene glycol dialkyl ethers; propylene glycol monoalkyl ether acetates can be used alone or selected from these solvents. Mixtures of at least one or two or more of the above solvents can also be used. Note that an additive (for example, an inorganic acid or the like is merely one example) may be added to the raw material liquid of the protective layer.

  The application of the protective layer precursor is not limited, but can be performed by, for example, a spraying method, a brush coating method, a dipping method, or the like. The protective layer precursor applied on the catalyst layer is dried so as to be reduced by evaporation of the solvent. Thus, the applied protective layer precursor may be subjected to drying at an elevated temperature, or the applied protective layer precursor may be placed under reduced pressure or vacuum. In the case of drying at a high temperature, for example, the applied protective layer precursor is dried under atmospheric pressure at a drying temperature of about 80 to 200 ° C. (one example is 100 ° C. to 150 ° C.) for about 2 to 40 minutes. It is preferred to attach. In the case where the protective layer precursor is placed under reduced pressure or under vacuum, the applied protective layer precursor is preferably placed under reduced pressure or vacuum of, for example, 7 to 0.1 Pa. If necessary, “under reduced pressure or under vacuum” and “heat treatment” may be combined. One more specific mode of applying the drying temperature condition is to exemplify a protective layer precursor applied by using an appropriate dryer (for example, Daido Kogyosho, explosion-proof dryer, DBO3-450, etc.). Drying of the body can be performed. After being subjected to such drying, the protective layer precursor is subjected to firing. The firing temperature is preferably from 300C to 600C, more preferably from 350C to 550C. The firing time is not particularly limited, but is preferably about 5 to 90 minutes, more preferably about 10 to 60 minutes. More specifically, the firing can be performed by using an appropriate firing furnace (for example, a heating furnace such as an electric furnace, a gas furnace, or an infrared furnace). Through the above-described coating, drying and baking, a desired protective layer is finally obtained.

  The application, drying, and baking are not limited to one time, and may be performed more times. This is because the thickness of the protective layer and the like can be appropriately adjusted. Although it is only an example, the steps of coating, drying and baking may be performed, for example, about 2 to 10 times.

<< Electrolytic metal foil manufacturing equipment using electrodes for electrolytic plating >>
An apparatus for manufacturing an electrolytic metal foil using the electrode of the present invention includes the electrode 100 of the present invention as an anode and the drum-shaped counter electrode 200 as a cathode (see FIG. 1).

  In the apparatus using an electrolytic metal foil, a desired separation distance (a distance between the proximal surfaces of both electrodes) is provided between the anode and the cathode, for example, about 5 to 25 mm. The electrode of the present invention used as an anode is mounted so as to face the cathode, while a drum-shaped counter electrode is rotatably provided as the cathode. That is, the cathode is provided in the electrolytic cell as a rotating drum. Specifically, it is preferable that approximately the lower half or more of the rotating drum of the cathode is provided so as to be immersed in the electrolytic solution (that is, the plating solution) of the electrolytic cell. The drum-shaped cathode itself may be conventional in the production of electrolytic metal foil. During metal foil production, the cathode drum rotates and electrodeposits when it contacts the electrolyte. Due to the rotation of the drum, a part of the cathode drum that has come into contact with the electrolyte is exposed to the air. At this time, the electrodeposition layer is mechanically separated from the drum surface. Thereby, a desired metal foil can be obtained. Since the metal foil is obtained continuously, a suitable reel means for winding it may be provided.

  The electrolytic metal foil device further comprises a bus bar for supplying power to the electrodes. For example, a busbar may be attached to the electrode substrate and / or support substrate of the electrode. With such a bus bar, a direct current can be passed between the anode and the cathode, and desired electroforming can be performed. Further, the support base or the like may have a supply port (for example, a gap) that contributes to the supply of the electrolytic solution. Through such a supply port, the consumed plating component may be appropriately replenished.

  As described above, various aspects of the present invention have been described. However, the present invention is not limited thereto, and various aspects may be embodied by those skilled in the art without departing from the scope of the invention defined in the claims. It will be understood that it gets.

  Various demonstration tests were performed in connection with the present invention.

`` Relative comparison of catalyst consumption rates ''
An electrolytic test was performed to confirm the effect of additives on the electrolyte and the effect of the protective layer in the present invention.

  Specifically, an electrolytic test simulating the production of an electrolytic metal foil was performed in accordance with Examples 1 to 4 and Comparative Example 1 and “conditions for“ without additives ”of the electrolytic solution”, and the catalyst consumption rates were compared.

● Example 1
An electrolytic test was performed using the following test electrodes.
Test electrode (anode for production of electrolytic metal foil)
・ Electrode laminated structure: (lower) electrode substrate / intermediate layer / catalyst layer / protective layer (upper)
・ Electrode base material: Valve metal (titanium)
Thickness: 1-3mm
・ Intermediate layer Material: Tantalum Thickness: 5-10 μm
・ Catalyst layer Material: Platinum group metal (iridium)
Thickness: 5-20 μm
-Protective layer Material: iridium and tantalum (weight ratio of Ir: Ta: 5:95) (iridium component: manufactured by Tokyo Chemical Industry, tantalum component: manufactured by Tokyo Chemical Industry),
Thickness: 5-10 μm
Solvent of raw material liquid (protective layer precursor): butanol (manufactured by Tokyo Chemical Industry)
Drying temperature after application of raw material liquid: 120 ° C
Firing temperature after drying: 400 ° C
Preparation method of protective layer A commercially available electrode for a metal foil having a laminated structure of an electrode substrate / intermediate layer / catalyst layer (a laminated structure in which a catalyst layer is provided on an electrode substrate with an intermediate layer interposed therebetween) (Daiso The protective layer was formed as a top coat by applying, drying, and baking a raw material liquid of the protective layer precursor to Engineering Co., Ltd., product number: MD-160). A series of steps of coating, drying and baking were repeated 5 to 10 times until a predetermined thickness was obtained.
Electrolysis test conditions -Counter electrode (cathode): Platinum plate (10 mm x 10 mm)
・ Reference electrode: Silver-silver chloride electrode
・ Current density: 100 A / dm ²
・ Electrolysis temperature: 80 ° C
Electrolytic solution: 20 wt% _H 2 SO ₄ and 10 wt% _Na 2 SO ₄
・ Additive: Saccharin (Tokyo Kasei Kogyo) 1000ppm
Catalyst depletion rate of grasping initial catalytic amount W _Initial from: Subtract "predetermined time (T 300 hours) a catalytic amount W _{after the electrolytic} after electrolysis", specifically the catalyst layer of the electrode by dividing it by the time T Was calculated. The calculation formula is as follows. The “initial catalyst amount W _initial stage” and “catalyst amount W _{after electrolysis} W _{after electrolysis} ” were each determined by X-ray fluorescence analysis (MESA Portable, a handheld X-ray fluorescence analyzer manufactured by Horiba, Ltd.).
V = (W _{initial- after} W _electrolysis ) / T

● Example 2
An electrode was prepared under the same conditions as in Example 1 except that the firing temperature of the protective layer was set to "490 ° C.", and the same electrolytic test was performed.
● Example 3
An electrode was prepared under the same conditions as in Example 1 except that the material condition of the protective layer was set to “100% tantalum”, and the same electrolytic test was performed.
● Example 4
An electrode was prepared under the same conditions as in Example 1 except that the material condition of the protective layer was “100% tantalum” and the firing temperature condition of the protective layer was “490 ° C.”, and the same electrolytic test was performed. Was.
● Comparative Example 1 (without protective layer)
Except that the protective layer was not provided, the same electrolysis test was performed using the electrode under the same conditions as in Example 1. More specifically, an electrode of product number MD-160 manufactured by Daiso Engineering Co., Ltd. was subjected to an electrolytic test.
● "No additive" condition of electrolyte solution The same electrolysis test as in Comparative Example 1 was performed except that the electrolyte solution did not contain any additives.

The test results are shown in FIG. The following items could be understood from the graph of FIG.
-The additives used in the electrolyte promote the consumption of the catalyst layer of the electrode.
-The protective layer contributes to protection of the catalyst layer.
In particular, the provision of the protective layer reduces the catalyst consumption rate, and the protective layer suppresses catalyst consumption.

"Confirmation test of protective layer characteristics"
A test was conducted to confirm the characteristics of the protective layer that suppresses catalyst consumption. In particular, the inventor of the present application has found that through the above test, the surface characteristics of the electrode surface (top surface) may be different, that is, the surface characteristics of the electrode having the protective layer may be different from those of the electrode having no protective layer. The test was conducted to confirm the surface area of the electrode.

Specifically, the following cyclic voltammetry was performed, and the surface areas of the electrodes A, B, and C were relatively compared.
-Electrode A : electrode used in "Comparative Example 1 (no protective layer)"- Electrode B : electrode used in "Example 2" -Electrode C : electrode used in "Example 1"
Cyclic voltammetry (CV)
As a CV measuring device, an automatic polarization system HSV-110 (Hokuto Denko Co., Ltd.) was used.
Measurement procedure (evaluation method)
(1) First, a measurement cell as shown in FIG. 2 was assembled.
(2) Next, the terminals of the HSV-110 were connected to the working electrode, the counter electrode, and the reference electrode.
(3) Pretreatment of the working electrode was performed.
(4) Measurement was performed at a predetermined scanning speed.
Measurement conditions and temperature during measurement: room temperature (about 25 ° C)
・ Electrolyte: 0.5M sulfuric acid aqueous solution ・ Working electrode: Each of the above electrodes A, B and C (electrolysis area 10 mm × 10 mm)
-Counter electrode: Platinum plate (25 mm x 25 mm)
-Reference electrode: Silver-silver chloride electrode-Pretreatment conditions: 10 cycles were performed in the range of 0.5 to 1.0 V (vs. Ag / AgCl) at a scanning speed of 100 mV / s.
Measurement conditions: Three cycles were performed at a scanning speed of 10 mV / s in the range of 0.5 to 1.0 V (vs. Ag / AgCl).

The results are shown in FIGS. The following items can be grasped from the graphs of FIGS.
-The surface area of the electrode having the protective layer is relatively smaller than the surface area of the electrode having no protective layer.
-Specifically, the surface area of the electrode having the protective layer is as small as 20% to 90% of the surface area of the electrode having no protective layer.

  Based on both the "relative comparison of catalyst consumption rate" and "confirmation test of protective layer characteristics", the electrode for electrolytic plating with a protective layer provided on the catalyst layer is used during the production of electrolytic metal foil. It has been found that the surface area of the electrode having the protective layer contributing to such a suppressing effect has a relatively smaller surface area than the surface area of the electrode having no protective layer.

  The electrode according to the present invention can be used in various fields where electrolytic plating is performed. In particular, it can be suitably used in electroforming for producing an electrolytic metal foil. Although merely an example, the electrode according to the present invention can be suitably used as an anode of an apparatus for producing an electrolytic metal foil used for a printed circuit material or an electrode current collector of a secondary battery.

DESCRIPTION OF SYMBOLS 10 Electrode base material 30 Catalyst layer 50 Protective layer 60 Intermediate layer 100 Electrode for electroplating 150 Substrate 200 Counter electrode

Claims (13)

An electrode for electrolytic plating,
Electrode substrate,
Comprising a catalyst layer provided on the electrode substrate, and a protective layer provided on the catalyst layer,
An electrode for electrolytic plating, wherein the surface area of the electrode having the protective layer is relatively smaller than the surface area of the electrode having no protective layer. The surface area _{S a} of the electrode having a protective layer satisfies the condition of _{0.2 × S b ≦ S a ≦} 0.9 × S b in relation to the surface area _{S b} of the electrode having no the protective layer, claim 2. The electrode for electrolytic plating according to 1. The electrode for electrolytic plating according to claim 1, wherein the surface area is a specific surface area based on cyclic voltammetry. The electrode for electrolytic plating according to any one of claims 1 to 3, wherein the protective layer forms an uppermost layer in the electrode. The electrode for electrolytic plating according to claim 1, wherein the electrode corresponds to an anode for electrolytic plating. The electrode for electrolytic plating according to any one of claims 1 to 5, wherein the protective layer comprises a transition metal. The electrode for electrolytic plating according to claim 6, wherein the transition metal is a metal of a Group 5 element. The electrode for electrolytic plating according to claim 6, wherein the protective layer comprises tantalum. The electrode for electrolytic plating according to claim 6, wherein at least two kinds of metals are included in the protective layer as the transition metal. The electrode for electrolytic plating according to claim 9, wherein the two kinds of metals are a metal of a group 5 element and a metal of a platinum group element. The electrode for electrolytic plating according to claim 1, wherein the catalyst layer includes a metal of a platinum group element. The electrode for electrolytic plating according to any one of claims 1 to 11, wherein the electrode base material includes a valve metal. The electrode for electrolytic plating according to any one of claims 1 to 12, further comprising an intermediate layer between the electrode substrate and the catalyst layer.

Images