Manufacturing method for base plates for specially shaped electrodeposited materials

Abstract

The present invention provides a method for manufacturing a base plate for specially shaped electrodeposited materials that can form an insulating layer of a desired thickness regardless of the ambient temperature. [Solution] The method for manufacturing a base plate for specially shaped electrodeposited material includes a preparation step of preparing multiple types of screens 20 with different ink volumes in the screen mesh, a screen selection step of selecting one of the multiple types of screens 20 according to the ambient temperature, and a printing step of obtaining a base plate by masking the surface of the metal plate 11 with insulating resin 31, leaving multiple electrodeposited parts 12, by screen printing using the selected screen 20. By selecting a suitable type of screen 20 according to the ambient temperature, an insulating layer 13 with a desired thickness can be formed regardless of the ambient temperature.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a base plate for specially shaped electrodeposited materials. More specifically, the present invention relates to a method for manufacturing a base plate used in electrolytic smelting for manufacturing specially shaped electrodeposited materials, wherein the surface of a metal plate is masked with an insulating resin while leaving the electrodeposited portion intact. [Background technology]

[0002] In the electrolytic extraction of nickel, a metal plate made of a reusable material other than nickel is used as a cathode. After electrolysis for a predetermined time, the electrodeposited material is peeled off the metal plate and recovered. In this process, by masking the surface of the metal plate with insulating resin while leaving the electrodeposited portion intact, electrodeposited material of any special shape can be obtained.

[0003] For electroplating, electrolytic nickel used as an anode is preferably in the form of small, rounded lumps (e.g., hemispherical or disc-shaped) with no sharp edges, considering factors such as ease of filling into the anode box of the electroplating apparatus and ease of handling. To produce electrolytic nickel of this shape, electroplating is performed using a base plate, where the surface of a metal plate is masked with insulating resin while leaving numerous circular electrodeposited areas, as the cathode.

[0004] Patent Document 1 discloses a method for manufacturing a base plate for specially shaped electrodeposited materials by screen printing. In this method, first, a screen having a masking pattern is placed on a metal plate, and insulating resin is supplied onto the screen. Next, a squeegee is moved while pressing it against the screen to transfer the insulating resin to the metal plate, and the screen is peeled off from the metal plate. This results in a base plate in which the surface of the metal plate is covered with an insulating layer, leaving the electrodeposited portion intact. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-172432 [Overview of the project] [Problems that the invention aims to solve]

[0006] If the insulating layer surrounding the electrodeposited area formed on the base plate is thin, the electrodeposition process may involve the insulating layer. Electrodeposited material that involves the insulating layer is considered a defective product with resin adhesion defects and is not accepted as a product; it is re-melted. Therefore, a high defect rate reduces production efficiency and increases manufacturing costs. To reduce the occurrence rate of resin adhesion defects, it is preferable, for example, to make the insulating layer at least 300 μm thick.

[0007] Furthermore, the base plate is repeatedly used in electrolytic smelting. After repeated use, the base plate undergoes refurbishment because the insulating layer deteriorates, such as peeling of the insulating layer around the electrodeposited area due to the resin adhesion defects mentioned above. Refurbishment of the base plate is performed by removing the insulating layer from the metal plate by blasting or the like, and then masking the surface of the metal plate again with insulating resin. Since the efficiency of blasting and the like decreases if the insulating layer is too thick, for example, the thickness of the insulating layer is preferably 400 μm or less.

[0008] As described above, the thickness of the insulating layer is preferably in the range of 300 to 400 μm. However, the thickness of the insulating layer fluctuates under the influence of ambient temperature, such as the ambient temperature during screen printing, the temperature of the insulating resin, and the temperature of the metal plate. For example, when the ambient temperature during screen printing is low, the insulating layer tends to be thicker, and when the ambient temperature is high, the insulating layer tends to be thinner. Therefore, there is a need for a technology that can form an insulating layer with a desired thickness regardless of the ambient temperature.

[0009] In view of the above circumstances, the present invention aims to provide a method for manufacturing a base plate for specially shaped electrodeposited materials that can form an insulating layer having a desired thickness regardless of the ambient temperature. [Means for solving the problem]

[0010] The first embodiment of the method for manufacturing a base plate for specially shaped electrodeposited material is characterized by comprising: a preparation step of preparing a screen in which a masking pattern is formed on the screen mesh, wherein a plurality of types of screens are prepared, each having a different ink volume of the screen mesh represented by the following formula (1); a screen selection step of selecting one of the plurality of types of screens according to the ambient temperature; and a printing step of obtaining a base plate by masking the surface of a metal plate with an insulating resin, leaving a plurality of electrodeposited parts, by screen printing using the selected screen. V=(W 2 ×T) / (W+φ) 2 ...(1) Here, V is the ink volume of the screen mesh [cm³] 3 / m 2 ], W is the opening width of the screen mesh [μm], T is the mesh thickness of the screen mesh [μm], and φ is the wire diameter of the screen mesh [μm]. The second embodiment of the method for manufacturing a base plate for specially shaped electrodeposited material is characterized in that, in the first embodiment, the ambient temperature is the ambient temperature, the temperature of the insulating resin, or the temperature of the metal plate. The third embodiment of the method for manufacturing a base plate for specially shaped electrodeposited material is characterized in that, in the first embodiment, in the screen selection step, when the ambient temperature is high, a screen with a larger ink volume in the screen mesh is selected compared to when the ambient temperature is low. The fourth embodiment of the method for manufacturing a base plate for specially shaped electrodeposited material is characterized in that, in the first embodiment, the thickness of the insulating layer formed with the insulating resin in the printing step is 300 to 400 μm. The fifth embodiment of the method for manufacturing a base plate for specially shaped electrodeposited material is characterized in that, in any of the first to fourth embodiments, the insulating resin is a resin composition containing a bisphenol A type epoxy resin and a phenol novolac type epoxy resin. [Effects of the Invention]

[0011] According to the present invention, by selecting a suitable type of screen according to the ambient temperature, an insulating layer having a desired thickness can be formed regardless of the ambient temperature.

Brief Description of the Drawings

[0012] [Figure 1] It is a front view of the mother board. [Figure 2] Figure (A) is a front view of the screen. Figure (B) is an enlarged cross-sectional view of the screen. [Figure 3] Figure (A) is an enlarged front view of the screen mesh. Figure (B) is an enlarged cross-sectional view of the screen mesh. [Figure 4] It is a detailed process diagram of the printing process.

Modes for Carrying Out the Invention

[0013] Next, embodiments of the present invention will be described based on the drawings. The method according to an embodiment of the present invention is a method for manufacturing a mother board for a special-shaped electrodeposit (hereinafter, simply referred to as "mother board"). The mother board is used in electrolytic smelting for manufacturing a special-shaped electrodeposit. The special-shaped electrodeposit refers to an electrodeposit of any shape such as a hemispherical shape or a disk shape obtained without cutting, with respect to a rectangular electrodeposit obtained by cutting a plate-shaped electrodeposit into a grid shape. The material of the electrodeposit is a metal such as nickel or cobalt. Examples of electrolytic smelting include electrolytic extraction and electrolytic refining.

[0014] Prior to the description of the mother board manufacturing method according to the present embodiment, as an example of a special-shaped electrodeposit, a method for manufacturing a hemispherical or disk-shaped nickel electrodeposit (generally referred to as "button-type electric nickel") by electrolytic extraction will be described.

[0015] First, a mother board is manufactured. As shown in FIG. 1, the mother board 10 is obtained by covering the surface of a metal plate 11 made of stainless steel or titanium with an insulating layer 13 while leaving a plurality of electrodeposited portions 12. The metal plate 11 is, for example, a rectangle with a length of 1,000 to 1,200 mm and a width of 800 to 900 mm. A beam 15 made of copper or a clad material containing copper is provided at the upper edge of the metal plate 11 via a hanging handle 14. The manufacturing method of the mother board 10 will be described in detail later.

[0016] In the example shown in FIG. 1, the metal plate 11 is masked in a pattern where a large number of circular electrodeposited portions 12 are arranged in a staggered manner. For example, the diameter of the electrodeposited portion 12 is 12 to 16 mm. The shortest distance between adjacent electrodeposited portions 12 is 5 to 6 mm. Both sides of the metal plate 11 are masked. The number of electrodeposited portions 12 is 3,000 to 5,000 on both sides of the metal plate 11. Note that the shape of the electrodeposited portion 12 is not limited to circular, and other shapes such as elliptical or rectangular may also be used.

[0017] Next, electrolytic extraction is performed using the mother plate 10 as a cathode. Specifically, a plurality of cathodes and a plurality of anodes are alternately inserted into an electrolytic cell filled with an electrolytic solution, and electrolysis is performed by applying an electric current. In the case of electrolytic extraction of nickel, an insoluble electrode equipped with an anode box is used as the anode. Also, an aqueous nickel chloride solution is used as the electrolytic solution, and this is continuously supplied to the electrolytic cell. By applying an electric current for a predetermined time (for example, 4 to 10 days), electro-nickel is electrodeposited on the electrodeposited portion 12 of the mother plate 10.

[0018] After the electrodeposit deposited on the electrodeposited portion 12 grows to the thickness of the insulating layer 13, it grows in both the direction perpendicular and parallel to the metal plate 11. That is, the electrodeposit grows beyond the range of the electrodeposited portion 12 and into the region where the insulating layer 13 exists. When the shape of the electrodeposited portion 12 is circular, the electrodeposit grows into a button shape with a flat central portion and a raised peripheral portion.

[0019] Electrolytic extraction is operated under conditions where the electrodeposit grows to the target dimensions. Specifically, operating conditions such as the composition of the electrolytic solution, the current between the anode and cathode, and the energization time are set so that the electrodeposit grows to the target dimensions. For example, after the completion of electrolytic extraction, the electrodeposit is in the shape of a button with a diameter of 16 to 19 mm and a thickness of about 5 mm.

[0020] After applying an electric current for a predetermined time, the mother plate 10 is removed from the electrolytic cell. Vibration is applied to the mother plate 10 by a method such as hammering to peel off the electrodeposit deposited on the mother plate 10. The electrodeposit peeled off from the mother plate 10 undergoes polishing, washing, and drying to become a product.

[0021] The base plate 10, from which the electrodeposited material has been stripped, is reinserted into the electrolytic cell as a cathode and used for electrolytic extraction. In other words, the base plate 10 is repeatedly used for electrolytic extraction. Repeated use of the base plate 10 causes the insulating layer 13 to deteriorate and peel off, resulting in a higher failure rate. When the failure rate exceeds a standard value, it is determined that the insulating layer 13 has reached the end of its lifespan, and the base plate 10 is refurbished.

[0022] The refurbishment of the base plate 10 is first carried out by removing the insulating layer 13 from the metal plate 11. The insulating layer 13 is removed, for example, by blasting. The metal plate 11 from which the insulating layer 13 has been removed is then masked again with insulating resin.

[0023] Next, the manufacturing method of the base plate 10 in this embodiment will be described. The base plate 10 is manufactured by screen printing. The screen 20 shown in Figures 2(A) and 2(B) is used for screen printing.

[0024] The screen 20 is formed by creating a masking pattern on the screen mesh 21 that corresponds to multiple electrodeposited areas 12. The masking pattern is such that the areas to be coated with insulating resin are open, and the areas not to be coated with insulating resin are closed. In the screen 20, the areas corresponding to the electrodeposited areas 12 are closed, and the other areas are open.

[0025] The screen mesh 21 is a net formed by weaving together wire materials such as synthetic fibers and metal wires. The masking pattern is formed, for example, by the following procedure. First, tension is applied to the screen mesh 21 to make it taut, and its outer circumference is adhered to the frame. Next, a photosensitive agent is applied to the screen mesh 21, and a positive film of the masking pattern is placed on top of it. Ultraviolet light is shone through the positive film onto the photosensitive agent to partially harden it. The hardened areas of the photosensitive agent become the positive areas 22. The unhardened photosensitive agent is washed away with water to expose the mesh area 23. This forms the masking pattern.

[0026] In this specification, the standard values ​​for the screen mesh 21 are defined as follows. As shown in Figure 3(A), the diameter of the wires constituting the screen mesh 21 before weaving is called the wire diameter φ [μm]. The distance between the edges of two adjacent wires is called the opening width W [μm]. As shown in Figure 3(B), the thickness of the screen mesh 21 is called the mesh thickness T [μm]. The theoretical ink permeation volume is called the ink volume V [cm³]. 3 / m 2 The ink volume V can be calculated using the following formula (1). Note that all standard values ​​used are those under tension-free conditions. V=(W 2 ×T) / (W+φ) 2 ...(1)

[0027] In this embodiment, multiple types of screens 20 with different ink volumes V of the screen mesh 21 are prepared in advance (preparation step). As can be seen from equation (1), the ink volume V is determined by the opening width W, mesh thickness T, and wire diameter φ. Therefore, for example, increasing the opening width W increases the ink volume V. Also, increasing the mesh thickness T increases the ink volume V.

[0028] When manufacturing the base plate 10, one type of screen 20 is selected from several types of screens 20 according to the ambient temperature (screen selection process). Here, ambient temperature refers to the temperature that affects the thickness of the insulating layer 13 formed on the metal plate 11. Examples of ambient temperature include the outside temperature, the temperature of the insulating resin used in the subsequent printing process, and the temperature of the metal plate 11.

[0029] The temperature of the insulating resin and the metal plate 11 can be adjusted. The temperature of the insulating resin can be adjusted, for example, by heating or cooling the entire container in which the insulating resin is stored. A water bath can be used to heat the container, and a water cooler can be used to cool the container. The temperature of the metal plate 11 can be adjusted, for example, by adjusting the temperature and time when the metal plate 11 is stored in a drying oven.

[0030] On the other hand, controlling the ambient temperature is difficult. For example, one could consider installing the screen printing equipment in a cleanroom and controlling the ambient temperature by air conditioning the cleanroom. However, since insulating resins contain volatile organic solvents, this would create problems in the working environment. Because controlling the ambient temperature is difficult in this way, the ambient temperature is particularly important as a surrounding temperature when selecting the screen 20.

[0031] When the ambient temperature is high, a screen 20 with a larger ink volume V of the screen mesh 21 is selected compared to when the ambient temperature is low. When the ambient temperature is high, a screen 20 with a larger opening width W of the screen mesh 21 may be selected compared to when the ambient temperature is low, or a screen 20 with a thicker mesh T of the screen mesh 21 may be selected, or a screen 20 with both a large opening width W and a thicker mesh T may be selected. When the ambient temperature is low, a screen 20 with a smaller ink volume V of the screen mesh 21 is selected compared to when the ambient temperature is high.

[0032] For example, two types of screens 20 are prepared: one for spring, summer, and autumn, and another for winter. The spring, summer, and autumn screen 20 has a larger ink volume V in the screen mesh 21 compared to the winter screen 20. The spring, summer, and autumn screen 20 is selected when the outside temperature is high. The winter screen 20 is selected when the outside temperature is low.

[0033] Next, the base plate 10 is manufactured by screen printing using the selected screen 20 (printing process). As shown in Figure 4, the printing process mainly consists of three sub-processes: (1) screen placement process, (2) insulating resin supply process, and (3) transfer process.

[0034] (1) Screen placement process In the screen placement process, the screen 20 is placed on the surface of the metal plate 11.

[0035] (2) Insulating resin supply process Next, in the insulating resin supply step, insulating resin 31 is supplied onto the screen 20. The insulating resin 31 is spread uniformly on the screen 20 by moving the scraper 32 along the surface of the screen 20. The insulating resin 31 is preferably an epoxy resin, and among these, a resin composition containing bisphenol A type epoxy resin and phenol novolac type epoxy resin is preferred.

[0036] (3) Transfer process Next, in the transfer process, the squeegee 33 is pressed down onto the screen 20 and moved along the surface of the screen 20. This transfers the insulating resin 31 present in the mesh portion 23 of the screen 20 to the metal plate 11. As a result, the insulating resin 31 is applied to the metal plate 11 along the masking pattern of the screen 20. The squeegee 33 may have a spatula structure or a roller structure.

[0037] As the squeegee 33 is moved, the portion of the screen 20 that the squeegee 33 has passed over is lifted and peeled away from the metal plate 11. This can be done by grasping one end of the screen 20 located on the opposite side of the direction of movement of the squeegee 33 (the right end in the example shown in Figure 4) and lifting it. By peeling off the screen 20, the insulating resin 31 applied to the surface of the screen 20 is extracted from the mesh portion 23 of the screen 20, forming an insulating layer 13 on the surface of the metal plate 11. The area of ​​the surface of the metal plate 11 that was not coated with insulating resin 31 becomes the electrodeposited portion 12. In this way, the base plate 10 is obtained by masking the surface of the metal plate 11 with insulating resin 31 while leaving the electrodeposited portion 12.

[0038] The thickness of the insulating layer 13 formed on the metal plate 11 is greater than the mesh thickness of the screen 20. Although the detailed mechanism is largely unknown, it is presumed to be as follows: When the insulating resin 31 is spread on the screen 20 with the scraper 32, the insulating resin 31 forms a layer of a certain thickness on the screen 20. When the insulating resin 31 is transferred to the metal plate 11 with the squeegee 33, the layer of insulating resin 31 formed on the screen 20 flows through the mesh portion 23 to the underside of the screen 20 and onto the metal plate 11. As a result, an insulating layer 13 thicker than the mesh thickness of the screen 20 is formed.

[0039] Generally, when the ambient temperature during screen printing is low, the insulating layer 13 tends to be thicker, and when the ambient temperature is high, the insulating layer 13 tends to be thinner. This is because when the ambient temperature is low, the insulating resin 31 cools rapidly, increasing its viscosity. As a result, it bonds strongly with the metal plate 11, and it is thought that a large amount of insulating resin 31 passes through the mesh portion 23 and adheres to the metal plate 11, resulting in a thicker insulating layer 13. Conversely, when the ambient temperature is high, the insulating resin 31 does not cool easily, so its viscosity decreases. As a result, some of the insulating resin 31 remains on the screen 20 during transfer, which is thought to result in a thinner insulating layer 13.

[0040] If the ambient temperature is low, the insulating layer 13 may become too thick, and conversely, if the ambient temperature is high, the insulating layer 13 may become too thin. Thus, the thickness of the insulating layer 13 is affected by the ambient temperature, and may not be at an appropriate thickness.

[0041] As mentioned above, the insulating resin 31 and the metal plate 11 can be preheated. However, since the insulating layer 13 is extremely thin, only 300-400 μm thick, the insulating resin 31 cools rapidly as soon as it is uniformly spread on the screen 20, especially in winter. Conversely, the same applies if the insulating resin 31 and the metal plate 11 are preheated based on winter conditions. Therefore, it is practically difficult to maintain a constant temperature of the insulating resin 31 during transfer, regardless of the season, as ambient temperatures fluctuate.

[0042] In contrast, in this embodiment, a suitable type of screen 20 is selected according to the ambient temperature, so that an insulating layer 13 with a desired thickness can be formed regardless of the ambient temperature. For example, when the ambient temperature is high, a screen 20 with a large ink volume V of the screen mesh 21 is selected. This makes it possible to form an insulating layer 13 of a desired thickness. The thickness of the insulating layer 13 is preferably 300 to 400 μm. An insulating layer 13 of such thickness can be formed regardless of the ambient temperature. [Examples]

[0043] Next, we will describe some examples. The base plate was manufactured using a screen printing type masking device manufactured by TEC Corporation. A SUS316L stainless steel plate measuring 1,090 mm in length and 830 mm in width was used as the metal plate. A resin composition containing bisphenol A type epoxy resin and phenol novolac type epoxy resin was used as the insulating resin. An insulating layer was formed on both sides of the metal plate in a pattern of staggered arrangement of perfectly circular electrodeposited areas with a diameter of 15 mm. The number of electrodeposited areas on one side of the metal plate was 2,021.

[0044] Base plates were prepared under various conditions, and the average thickness of the insulating layer was measured. Here, the average thickness of the insulating layer was calculated by selecting one plate from a population of 20-30 plates, measuring the thickness at nine locations on each side (top, middle, bottom) x (left, middle, right) (18 locations in total for both sides), and averaging the measured values. An electromagnetic measuring device was used to measure the thickness.

[0045] (Example 1) As the screen mesh, Smartmesh-P (registered trademark), product number 70S manufactured by Nippon Special Weaving Co., Ltd. was used to prepare the first screen. The screen mesh 70S has a wire diameter of 71 μm, an opening width of 292 μm, a yarn thickness of 115 μm, and an ink volume of 75 cm 3 / m 2 It is. At an outside air temperature of 21 °C, a mother board was manufactured using the first screen. When the average film pressure of the formed insulating layer was measured, it was 317 μm.

[0046] (Comparative Example 1) Using the same first screen as in Example 1, a mother board was manufactured at an outside air temperature of 31 °C. When the average film pressure of the formed insulating layer was measured, it was 293 μm. Thus, when the outside air temperature is high, the insulating layer becomes thin and cannot maintain 300 μm or more.

[0047] (Example 2) As the screen mesh, Smartmesh-P (registered trademark), product number 36SS manufactured by Nippon Special Weaving Co., Ltd. was used to prepare the second screen. The screen mesh 36SS has a wire diameter of 100 μm, an opening width of 606 μm, a yarn thickness of 173 μm, and an ink volume of 128 cm 3 / m 2 It is. At an outside air temperature of 31 °C, a mother board was created using the second screen. When the average film pressure of the formed insulating layer was measured, it was 357 μm. Thus, when the outside air temperature is high, by using the second screen with a large ink volume, an insulating layer having a preferable thickness can be formed.

Explanation of Signs

[0048] 10 Mother board 11 Metal plate 12 Electrodeposition part 13 Insulating layer 20 Screen 21 Screen mesh 22 Positive area 23 Mesh part 31 Insulating resin 32 Scraper 33 Squeegee

Claims

1. A preparation step of preparing a screen in which a masking pattern is formed on the screen mesh, wherein a plurality of types of the screen are prepared, each having a different ink volume of the screen mesh represented by the following formula (1), A screen selection step in which one of several types of screens is selected according to the ambient temperature, The printing process includes a step of obtaining a base plate by screen printing using the selected screen, masking the surface of a metal plate with an insulating resin while leaving multiple electrodeposited areas. A method for manufacturing a base plate for specially shaped electrodeposited materials, characterized by the following features. V=(W ２ ×T) / (W+φ) ２ ・・・(1) Here, V is the ink volume of the screen mesh [cm³]. ３ / m ２ ], W is the opening width of the screen mesh [μm], T is the mesh thickness of the screen mesh [μm], and φ is the wire diameter of the screen mesh [μm].

2. The ambient temperature is the ambient temperature, the temperature of the insulating resin, or the temperature of the metal plate. A method for manufacturing a base plate for specially shaped electrodeposited material according to claim 1.

3. In the screen selection step, when the ambient temperature is high, a screen with a larger ink volume in the screen mesh is selected compared to when the ambient temperature is low. A method for manufacturing a base plate for specially shaped electrodeposited material according to claim 1.

4. In the printing process, the thickness of the insulating layer formed with the insulating resin is 300 to 400 μm. A method for manufacturing a base plate for specially shaped electrodeposited material according to claim 1.

5. The insulating resin is a resin composition comprising a bisphenol A type epoxy resin and a phenol novolac type epoxy resin. A method for manufacturing a base plate for specially shaped electrodeposited material according to any one of features 1 to 4.

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