JP4426127B2 - Metal foil electrolytic manufacturing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrolytic production apparatus for metal foil, and more particularly to a production technique for achieving uniform thickness in the foil width direction of metal foil.
[0002]
[Prior art]
In recent years, metal foils have been produced in large quantities by being used in various applications, typically electrolytic copper foil, which is a printed wiring board material. As a method for producing such a metal foil, a method using an electrolytic reaction is known.
[0003]
As an apparatus for electrolytically producing metal foil utilizing this electrolytic reaction, for example, an apparatus for continuously producing metal foil using a drum-shaped rotating cathode shown in FIG. 4 is used. The metal foil electrolysis production apparatus 1 shown in FIG. 4 includes a drum-shaped rotating cathode 2 on which a metal foil is electrodeposited, an anode 3 disposed opposite to the circumferential surface of the rotating cathode 2, a rotating cathode 2 and an anode. 3 is provided with a liquid supply means 5 having an electrolyte supply port 4 for supplying an electrolyte from the lower side of the rotary cathode 2, and the rotary cathode 2 by an electrolytic reaction while supplying the electrolyte from the liquid supply means 5. A metal is electrodeposited on the peripheral surface, and the electrodeposited metal foil 6 is continuously peeled off from the rotating cathode 2.
[0004]
The metal foil obtained by such an electrolytic production apparatus has many characteristic requirements such as strength, surface properties, and thickness uniformity that can be used for each application, and must satisfy those requirements. In particular, in a copper foil used as a printed wiring board material, not only strength characteristics and surface properties, but also uniformity of the foil thickness is very important as the quality of the metal foil.
[0005]
The metal foil obtained by this metal foil electrolysis production apparatus is often produced in a roll shape from a long metal foil by continuously peeling off the metal deposited on the rotating cathode. In such a case, the thickness of the metal foil in the longitudinal direction can be controlled relatively easily by controlling the rotation speed of the rotating cathode, but it is possible to control the thickness uniformly in the width direction of the metal foil. It's not easy.
[0006]
Conventionally, in order to improve the thickness uniformity in the width direction of the metal foil obtained by this metal foil electrolytic manufacturing apparatus, the anode facing the rotating cathode is divided in the width direction, and the supply of the electrolytic current is controlled in the width direction. Countermeasures have been proposed.
[Problems to be solved by the invention]
[0007]
However, such an improvement in the current supply method can control the uniformity of the thickness in the width direction of the metal foil to some extent, but is not fully satisfactory. Moreover, in order to be able to supply different electrolysis currents to the divided anodes, the structure of the metal foil electrolysis production apparatus becomes complicated, which is not preferable in terms of apparatus design.
[0008]
Furthermore, the quality requirements for recent metal foils have become stricter with the technological progress of each application, and in particular, there is a tendency to strongly demand a metal foil with a thin foil thickness. For example, when viewed from an electrolytic copper foil used as a printed wiring board material, the conventional foil thicknesses of 35 μm and 18 μm have been mainstream, but recently, the demand for ultra-thin copper foils of 12 μm and 9 μm is increasing. When manufacturing such an ultra-thin copper foil with the above-described metal foil electrolysis manufacturing apparatus, if the thickness uniformity in the width direction is not accurately maintained, when the metal foil is peeled off from the rotating cathode and wound, It becomes difficult to use as a product. It is difficult to precisely control the uniformity of the thickness in the width direction necessary for manufacturing such an extremely thin metal foil in the conventionally proposed measures for the uniformity of the thickness in the width direction of the metal foil. . Therefore, in order to stably supply a thin metal foil such as ultra-thin copper foil to the market, it is essential to establish a metal foil electrolytic manufacturing technology that can make the thickness in the width direction even more precise than before. It can be said that.
[0009]
The present invention has been made in the background as described above. When a metal foil is continuously produced by electrodeposition using a drum-shaped rotating cathode, the foil thickness in the width direction of the metal foil is precisely determined. An object of the present invention is to provide a metal foil electrolytic production apparatus that can be uniformly controlled.
[0010]
[Means for Solving the Problems]
In order to solve the above problems, the present inventors have studied in detail a metal foil electrolysis production apparatus using a drum-shaped rotating cathode, and the liquid flow state of the electrolyte supplied between the rotating cathode and the anode However, focusing on the fact that the thickness uniformity in the width direction of the metal foil is greatly affected, the present invention has been conceived.
[0011]
The present invention provides a drum-shaped rotating cathode on which a metal foil is electrodeposited, an anode disposed oppositely along the circumferential shape of the rotating cathode, and an electrolyte solution from the lower side of the rotating cathode between the rotating cathode and the anode. A liquid supply means having an electrolyte supply port for supplying the electrode, and while supplying the electrolyte solution from the liquid supply means, a metal is electrodeposited on the peripheral surface of the rotating cathode by an electrolytic reaction, and the electrodeposited metal foil is continuously formed from the rotating cathode. In the metal foil electrolysis manufacturing apparatus that is to be peeled off, the liquid supply means is provided with a plate-like damper body extending in the width direction of the rotating cathode above the electrolyte supply port.
[0012]
When supplying the electrolyte from the lower side of the rotating cathode between the drum-shaped rotating cathode on which the metal foil is electrodeposited and the anode arranged opposite to the peripheral surface of the rotating cathode, the broken line arrow in FIG. As shown, the supplied electrolytic solution collides with the surface of the rotating cathode at a position facing the electrolytic solution supply port, and forms a liquid flow that rises in two directions along the circumferential shape of the rotating cathode.
[0013]
In the vicinity of the surface of the rotating cathode facing the electrolyte supply port, the electrolyte collides with the surface of the rotating cathode, so that an eddy current state is likely to occur, and compared with a liquid flow state that rises along the shape of the surface of the rotating cathode. Complicated liquid flow. In addition, since a new electrolyte is continuously supplied on the surface of the rotating cathode facing the electrolyte supply port, the metal ions to be subjected to electrodeposition are always sufficiently supplied. . Considering this, the liquid flow is complicated on the surface of the rotating cathode facing the electrolyte supply port, so the amount of electrolyte supplied when viewed in the width direction is less than that of other rotating cathode surfaces. It is thought that it becomes easy to become uniform. And, on the surface of the rotating cathode where the electrolytic solution collides, metal ions for electrodeposition are always sufficiently supplied, so that electrodeposition causing non-uniform thickness in the width direction of the metal foil occurs. The inventors have speculated.
[0014]
Accordingly, the present inventors have provided a plate-like damper body that extends in the width direction of the rotary cathode above the electrolyte supply port in order to eliminate the complicated liquid flow state that occurs on the surface of the rotary cathode that faces the electrolyte supply port. It was made to provide. As a result of eliminating this complicated liquid flow state that occurs near the surface of the rotating cathode at a position facing the electrolyte supply port by providing this plate-like damper body, the thickness uniformity in the width direction is as estimated by the present inventors. They found that it can be greatly improved. It was also found that the installation of this plate-like damper body has an effect of reducing abnormal precipitation that occurs on the surface of the metal foil.
[0015]
The plate-like damper body of the metal foil electrolysis production apparatus according to the present invention is in a liquid flow state in which the electrolyte supplied from the electrolyte supply port toward the surface of the rotating cathode directly collides with the surface of the rotating cathode. There is no restriction on its shape, arrangement, etc. In short, the state where the plate-like damper provided between the electrolytic supply port and the rotating cathode surface across the width direction of the rotating cathode obstructs the flow direction of the electrolytic solution supplied from the electrolytic solution supply port toward the rotating cathode surface. Any shape and arrangement may be used as long as they are.
[0016]
The plate-like damper body of the metal foil electrolytic production apparatus according to the present invention is desirably provided with a branching projection extending in the plate longitudinal direction at the plate width center. When a plate-like damper body is provided above the electrolyte solution supply port, the supplied electrolyte solution directly collides with the plate-like damper body, and a complicated liquid flow such as a vortex is easily formed in that portion. Therefore, if a projection for shunting is provided in the longitudinal direction of the plate at the center of the plate width of the plate-like damper body, the electrolytic solution that directly collides with the plate-like damper body is divided into two directions by the shunting projection, It rises smoothly along the rotating cathode peripheral surface shape. By providing the branching projections on the plate-like damper body, the thickness uniformity in the width direction of the metal foil can be improved more reliably.
[0017]
Moreover, in the metal foil electrolysis production apparatus according to the present invention, the electrolyte supply port is divided into a plurality in the width direction of the rotating cathode, and the flow rate of the electrolyte supplied from the divided electrolyte supply port can be adjusted. Is preferred. If it does in this way, it will become easy to control the thickness uniformity in the width direction of metal foil more precisely. In order to achieve high production efficiency, the metal foil electrolytic production apparatus according to the present invention often uses a relatively large rotating cathode or anode. In such a large metal foil electrolytic production apparatus, the apparatus is It is difficult to form the material of the rotating cathode and anode to be formed uniformly, and the larger the size, the easier the electrodeposition of each apparatus. Therefore, the thickness variation in the width direction of the manufactured metal foil also tends to be different for each apparatus. Even if there is a bias in electrodeposition for each device, the flow rate of the electrolyte supplied from the divided electrolyte supply port is adjusted in accordance with the thickness variation in the foil width direction of each device. Then, in synergy with the effect of the plate-like damper body according to the present invention, it is possible to easily control the thickness uniformity in the metal foil width direction with precision.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described.
[0019]
The metal foil electrolysis production apparatus of this embodiment has a structure basically similar to that of a conventionally used apparatus, and a schematic cross section thereof is shown in FIG. The metal foil electrolysis production apparatus 1 includes a drum-shaped rotating cathode 2 for electrodepositing a metal foil, and an anode 3 disposed so as to face the circumferential surface of the rotating cathode 2. The rotating cathode 2 and the anode 3 are connected to a power supply device (not shown). The rotating cathode 2 is so arranged that approximately half of its volume is immersed in the electrolyte. The anode 3 is divided into two parts, and an electrolyte supply means 5 having an electrolyte supply port 4 for supplying an electrolyte from below the rotary cathode 2 is provided between the divided anodes 3. . When the electrolytic solution is supplied from the electrolytic solution supply port 4 toward the rotating cathode 2, the electrolytic solution flows so as to rise along the circumferential shape of the rotating cathode 2 as shown by the broken line in FIG. It is supposed to overflow. The metal foil 6 electrodeposited on the peripheral surface of the rotating cathode 2 is peeled off from the rotating cathode 2 and wound on a winding roll 9 via a guide roll 8.
[0020]
FIG. 1 shows an enlarged perspective view of a portion surrounded by A in FIG. The electrolyte solution supply port 4 of the electrolyte solution supply means 5 is divided into a plurality of parts in the width direction of the rotary cathode 2, and the divided electrolyte solution supply ports 4 ′, 4 ′,. However, a flow rate adjusting means for adjusting the flow rate of the electrolyte to be supplied is provided.
[0021]
In FIG. 2, the cross-sectional enlarged view which has arrange | positioned the plate-shaped damper body to the upper part of the electrolyte solution supply port 4 in the metal foil electrolysis manufacturing apparatus 1 in this embodiment is shown. FIG. 3 is a partially enlarged perspective view of the plate-like damper body. The plate-like damper body 10 has a length substantially equal to the width of the rotary cathode 2 and slightly longer than the width of the electrolyte solution supply port 4. Is formed over the longitudinal direction of the plate. Further, a partition wall 12 is provided on the lower surface side of the plate-like damper body 10, that is, on the side facing the electrolyte solution supply port 4 according to the divided electrolyte solution supply port 4 ′. The partition wall 12 is erected on fixed plates 13 located on both sides of the electrolyte supply port 4. Therefore, a liquid outlet 14 is formed in the lower part of the plate-like damper body 10 in accordance with the divided electrolyte supply ports 4 ′, 4 ′,.
[0022]
When the plate-like damper body 10 shown in FIGS. 2 and 3 is arranged on the upper part of the electrolyte solution supply port 4, as shown by the arrow in FIG. 2, the electrolyte solution supplied from the electrolyte solution supply port 4 is the plate-like damper. It collides with the body 10, and the flow direction is changed by the diverting projection 11 to be divided into two directions, and a liquid flow state rising along the shape of the peripheral surface of the rotating cathode 2 is formed.
[0023]
Next, the result of investigating the thickness distribution and surface properties in the foil width direction of the produced copper foil by producing a copper foil as the metal foil by the metal foil electrolysis production apparatus according to the present embodiment will be described.
[0024]
When copper foil is manufactured as a metal foil, a drum-shaped rotating cathode (diameter 3 m, width 1.35 m) having a circumferential surface made of Ti and an insoluble anode called DSA are used, and the gap between the rotating cathode and the insoluble anode is small. A copper foil electrolytic production apparatus arranged to be about 20 mm was used. The plate-like damper body provided with the diverting projections is made of Ti material (the partition plate and the fixing plate are also made of Ti material), and at the intermediate position between the rotating cathode and the anode, Arranged above. The plate-like damper body was installed by interposing an insulating material between the anode and the fixed plate so that no electrolytic current flowed through the plate-like damper body. Moreover, the copper sulfate solution was used for electrolyte solution.
[0025]
In this copper foil electrolysis production apparatus, a copper foil is produced by performing an electrolytic treatment with and without a plate-like damper body, and the thickness distribution and surface properties in the copper foil width direction are comparatively investigated. did.
[0026]
First, the results of measuring the thickness distribution in the copper foil width direction will be described. The thickness distribution measurement in the width direction was performed with a copper foil that was electrolytically treated by supplying an electrolytic solution while the rotating cathode was stationary. The sample in which the thickness distribution in the width direction was measured was subjected to electrolytic treatment so that a copper foil having a thickness of 70 μm was formed, and after the electrolytic treatment was stopped, the electrodeposited copper foil was peeled off on the semicircular surface of the rotating cathode. Things were used. From the sample obtained by this static electrolysis, in the circumferential direction of the rotating cathode peripheral surface, a belt-like sample having a length of 150 mm × width of 1350 mm (rotating cathode width) is arranged in the front-rear direction around the portion facing the electrolyte supply port. A total of 4 sheets were cut out one by one (A to D).
[0027]
The cut strip samples were further subdivided into strips having a width of 10 mm and a length of 100 mm. By this subdivision, the strip sample was divided into 84 strips in the width direction. And by measuring each mass of this strip, mass thickness (g / m < ² >) was computed and this value was made into the thickness of copper foil.
[0028]
The four strip samples (A to D) cut out from the static electrolysis were measured for each mass of the 84 divided strips and plotted according to the position in the width direction as shown in FIG. 5 and FIG.
[0029]
FIG. 5 shows a case where a plate-like damper body is arranged, and FIG. 6 shows a case where the plate-like damper body is not arranged. In the strip samples A to D, a position between the strip samples B and C corresponds to a portion facing the electrolyte supply port. 5 and 6, the maximum mass thickness value is specified from 84 strips divided from the strip sample, the difference between the mass thickness value and the maximum mass thickness value of each strip is calculated, and each mass thickness difference is calculated. By dividing by the maximum mass thickness value, each thickness ratio (%) value is calculated and plotted.
[0030]
When the plate-like damper body is not arranged, when all the band-shaped samples A to D are viewed, a difference in mass thickness of 14.2% at maximum occurs, and there is a difference in mass thickness of 6.5% on average. It was. Further, as can be seen from FIG. 6, if the plate-like damper body is not arranged, the mass thickness in the width direction of each of the strip samples A to D varies considerably, and the standard deviation at this time is 3. 05 (value calculated from all data of A to D).
[0031]
On the other hand, when the plate-like damper body was arranged, the difference in mass thickness was reduced to 10.8% at the maximum, and the difference in mass thickness was 3.4% on average. Then, as can be seen from FIG. 5, when the plate-shaped damper body is arranged, the mass thickness in the width direction in each of the strip samples A to D becomes very uniform, and the standard deviation is 1.89 (all of A to D). It was confirmed that the value was calculated from the data of In addition, although the thickness distribution investigation in the width direction in the present embodiment is performed from those subdivided into strips having a width of 10 mm × a length of 100 mm, in the case of division at such a precise level in the copper foil width direction, The fact that it was possible to control the variation as small as the standard deviation of 1.89 was impossible at all with the conventional copper foil manufacturing apparatus.
[0032]
Then, the result of having investigated the surface property of copper foil is described. A comparative investigation of surface properties was performed by manufacturing a copper foil having a thickness of 35 μm and a length of 10 m, and observing abnormal precipitation on the rough surface (mat surface; surface corresponding to the electrodeposition end surface) of the obtained copper foil. went. This abnormal deposition refers to a portion that is deposited in an abnormally protruding state from the periphery on the electrodeposition end surface side of the surface of the metal foil to be manufactured. The surface property was examined by randomly collecting a 100 mm × 100 mm square sample from the produced copper foil, and observing the rough surface side of the sample with a stereomicroscope to confirm the presence or absence of abnormal precipitation. .
[0033]
As a result, many copper foils in which no plate-like damper body was provided were confirmed to be abnormal precipitation in almost all samples. On the other hand, in the copper foil in the case where the plate-like damper body is provided, in any sample, there are very few things that are seen as abnormal precipitation, and it was confirmed that the plate-like damper body is effective in reducing abnormal precipitation. .
[0034]
【The invention's effect】
According to the present invention, when a metal foil is continuously produced by electrodeposition using a drum-shaped rotating cathode, the thickness uniformity in the width direction of the metal foil can be precisely controlled. It is also possible to suppress the occurrence of abnormal precipitation.
[Brief description of the drawings]
FIG. 1 is a partially enlarged perspective view of a metal foil electrolytic production apparatus.
FIG. 2 is a partially enlarged cross-sectional view of a metal foil electrolytic manufacturing apparatus in which a plate-like damper body is disposed.
FIG. 3 is a partially enlarged perspective view of a plate-like damper body.
FIG. 4 is a schematic cross-sectional view of a metal foil electrolytic production apparatus.
FIG. 5 is a thickness distribution graph in the width direction when a plate-like damper body is arranged.
FIG. 6 is a thickness distribution graph in the width direction when a plate-like damper body is not arranged.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Metal foil electrolysis production apparatus 2 Rotating cathode 3 Anode 4, 4 'Electrolyte supply port 5 Liquid supply means 6 Metal foil 7 Electrolytic tank 8 Guide roll 9 Winding roll 10 Plate-shaped damper body 11 Dividing protrusion 12 Partition wall 13 Fixing Plate 14 Liquid outlet

Claims (3)

An electrolytic solution for supplying an electrolytic solution from below the rotating cathode between the rotating cathode and the anode, a drum-shaped rotating cathode for electrodepositing a metal foil, an anode disposed facing the circumferential surface of the rotating cathode, and the anode Liquid supply means having a supply port,
In the metal foil electrolysis production apparatus in which the metal is electrodeposited on the peripheral surface of the rotating cathode by electrolytic reaction while supplying the electrolyte from the liquid supply means, and the electrodeposited metal foil is continuously peeled off from the rotating cathode.
The liquid supply means comprises a plate-like damper body extending in the width direction of the rotating cathode above the electrolyte supply port. 2. The metal foil electrolytic manufacturing apparatus according to claim 1, wherein the plate-like damper body is provided with a branching projection extending in the plate longitudinal direction at the plate width center. 3. The metal foil electrolysis according to claim 1, wherein the electrolytic solution supply port is divided into a plurality of portions in the width direction of the rotating cathode, and the flow rate of the electrolytic solution supplied from the divided electrolytic solution supply port can be adjusted. Manufacturing equipment.

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