Stripping processing method for coated copper material, processing device, processing device control unit, program, and computer-readable recording medium storing program

Abstract

[Solution] A sulfuric acid solution is brought into contact with a coating material coated on a copper material, the coating material is dissolved in the sulfuric acid solution and stripped off the copper material, high-purity copper material is recovered with good yield, and the coating material dissolved in the sulfuric acid solution is decomposed with an electrolytic sulfuric acid solution, making the sulfuric acid solution regenerable.

Description

Stripping treatment method for coated copper material, treatment device, treatment device control unit, program, and computer-readable recording medium storing the program

[0001] The present invention relates to a method for stripping a coated copper material, a processing device, a processing device control unit, a program, and a computer-readable recording medium storing the program, for stripping and removing a coating material from a copper material coated with the coating material.

[0002] Copper wire is widely used in automobiles, home appliances, industrial applications, etc. However, copper is a resource that is expected to run out in about 40 years, and there are concerns about its depletion. Furthermore, copper mines have been experiencing a gradual decline in the quality of copper concentrate in recent years, which is said to be increasing the burden on the mining and smelting processes. In the automotive industry, there has been a sudden movement, primarily among European manufacturers, to recycle materials and parts used, and there is a demand for copper recovery from copper wire used in windings.

[0003] Copper wires are often coated with a resin that has insulating properties, and copper recovery requires stripping the coating material from the copper wire. Currently, the coating material is stripped from some copper wires used for windings using a dry method. One dry method involves making cuts with a rotary blade, then crushing the wire with opposing rolling rollers, and separating the wires based on the difference in specific gravity (Patent Document 1). As another processing method, Patent Document 2 discloses a recovery method in which resin-coated copper wires are heated at 250°C to 380°C in an air atmosphere, and the thermally denatured insulating coating is mechanically stripped.

[0004] As for wet recycling methods, Patent Document 3 discloses a recovery method in which the material is heated at 500°C to 800°C using superheated steam, and then washed with 10 to 35 mass% hydrochloric acid to remove the material. Patent Document 4 discloses a recovery method in which the material is chemically stripped using a stripping solution containing an inorganic alkali, an alkanolamine having 1 to 10 carbon atoms, and water.

[0005] Patent No. 5828145 Patent No. 6604515 Patent No. 6056088 Japanese Patent Application Laid-Open No. 2021-108531

[0006] However, in Patent Documents 1 and 2, the stripping rate of the coating material is low (approximately 97%) due to contamination with insulating coating components, and recycling requires processing starting from the smelting process. Patent Document 3 describes heating at 500°C to 800°C using superheated steam, followed by chemical stripping using hydrochloric acid. These conventional techniques require high heating temperatures and the need for mechanical or chemical removal after heating, resulting in multiple processing steps and increased equipment and processing costs. Furthermore, high-temperature heating can cause problems such as oxide formation on the copper wire, impairing its purity. Patent Document 4 also raises concerns about the cleanliness of the copper wire after stripping, and makes no mention of the state of the solution after stripping, raising concerns about the insulating coating removal ability of the stripping / removal solution as the number of uses increases.

[0007] When recovering high-purity copper wire, further issues include the cleanliness of the copper wire after stripping and the yield of the copper wire during stripping. Furthermore, a challenge in this field is how to completely remove the insulating coating while reducing energy costs and carbon dioxide emissions during recovery. Chemical removal methods are effective in solving these issues, but the used stripping / removal solution contains dissolved insulating coating components, and the stripping / removal ability decreases with increasing use, which limits the number of times it can be used. Furthermore, when disposing of used stripping / removal solutions, the following issues can easily be imagined as the number of stripping / removal processes increases: (1) Increased waste liquid treatment / replacement costs and collection / transportation costs; (2) Increased waste liquid treatment costs due to multiple waste liquid treatment processes; and (3) Increased environmental burden from waste liquid treatment replacement to recycling.

[0008] The present invention has been made in consideration of the above-mentioned conventional problems, and aims to provide a recovery method, etc., which can recover high-purity copper material from coated copper material with a high yield using only chemical treatment and can autodecompose the coating material components dissolved in the used solution.

[0009] That is, in the first form of the method for stripping a coated copper material, a sulfuric acid solution is brought into contact with a coating material coating a copper material, and the coating material is dissolved in the sulfuric acid solution to be stripped and removed from the copper material, and the coating material dissolved in the sulfuric acid solution is decomposed in an electrolytic sulfuric acid solution containing persulfuric acid.

[0010] In another aspect of the invention, in the above aspect of the invention, the concentration of persulfuric acid in the electrolytic sulfuric acid solution is 0.5 g / L or more.

[0011] In another aspect of the invention, in the above aspect of the invention, the sulfuric acid solution used to decompose the coating material is reused for stripping and removing the coated copper material or other coated copper materials.

[0012] In another aspect of the invention, in the above aspect of the invention, the sulfuric acid solution brought into contact with the coating material coating the copper material has a persulfuric acid concentration of less than 0.5 g / L, a sulfuric acid concentration of 85.0 mass% or more, and a temperature within a range of 60 to 140°C.

[0013] In another aspect of the invention, in the above aspect of the invention, the sulfuric acid solution brought into contact with the coating material coated on the copper material is an electrolytic sulfuric acid solution having a persulfuric acid concentration of 0.5 g / L or more in part or all of the peeling and removal process, and the sulfuric acid concentration is 80.0 mass% or more and the temperature is within the range of 60 to 140°C.

[0014] In another aspect of the invention, in the above aspect of the invention, the electrolytic sulfuric acid solution is electrolyzed at a solution temperature of 20 to 60°C.

[0015] The decomposition state of the coating material is determined by one or both of the electrical conductivity and the oxidation-reduction potential of the sulfuric acid solution.

[0016] When the decomposition state of the coating material reaches a standard, it is determined that the regeneration is complete, and the regenerated sulfuric acid solution is used to peel and remove the coated copper material.

[0017] The invention of the coating copper material peeling and removal treatment device has a sulfuric acid solution contact section that brings the coating material of the coated copper material into contact with a sulfuric acid solution, and a decomposition section that decomposes the coating material dissolved in the sulfuric acid solution with an electrolytic sulfuric acid solution.

[0018] In another aspect of the invention, in the above aspect of the invention, the sulfuric acid solution contact section has one or both of an immersion treatment tank in which the coated copper material is immersed in a sulfuric acid solution and a release contact tank in which sulfuric acid solution is released onto the coated material to bring it into contact with the coated material.

[0019] In another aspect of the invention, in the above aspect of the invention, the decomposition section is provided with an electrolysis section that electrolyzes a sulfuric acid solution.

[0020] In another aspect of the invention, in the above aspect of the invention, a plurality of the sulfuric acid solution contact sections are provided, and one or more of the electrolysis sections are capable of selectively electrolyzing the sulfuric acid solutions in the plurality of sulfuric acid solution contact sections.

[0021] In another aspect of the invention, in the above aspect of the invention, the decomposition section comprises a decomposition storage tank and an electrolysis section, and an electrolysis circulation path for circulating a sulfuric acid solution between the decomposition storage tank and the electrolysis section.

[0022] In another aspect of the invention, in the above aspect of the invention, a decomposition / regeneration liquid transfer path is provided between the sulfuric acid solution contact section and the decomposition storage tank.

[0023] Another aspect of the invention is the invention of the above aspect, which further comprises a measurement unit that measures the decomposition state of the sulfuric acid solution in the decomposition unit, and a control unit that controls electrolysis in the electrolysis unit and the liquid supply through the electrolysis circulation path and the decomposition / regeneration liquid supply path, and the control unit receives the measurement results of the measurement unit and determines the content of the control based on the measurement results.

[0024] Another form of the stripping device control unit invention is provided in a processing device having a measuring unit that measures the decomposition state of the coating material in a sulfuric acid solution containing persulfuric acid, a sulfuric acid solution contact unit that dissolves the coating material of the coated copper material by contact with the sulfuric acid solution to strip and remove it, a decomposition storage tank that decomposes the coating material dissolved in the sulfuric acid solution using an electrolytic sulfuric acid solution, a decomposition / regeneration liquid supply path provided between the sulfuric acid solution contact unit and the decomposition storage tank, an electrolysis unit that electrolyzes the sulfuric acid solution, and an electrolysis circulation path that circulates the sulfuric acid solution between the decomposition storage tank and the electrolysis unit, and receives the measurement results from the measuring unit and controls the electrolysis in the electrolysis unit and the liquid supply through the electrolysis circulation path and the decomposition / regeneration liquid supply path, and receives the measurement results and performs control to determine the content of the control based on the measurement results.

[0025] Another form of the program invention is a program executed by a control unit that receives measurement results from a measurement unit that measures the decomposition state of a coating material in a sulfuric acid solution containing persulfuric acid, and controls the liquid feed through a decomposition / regeneration liquid feed path provided between a sulfuric acid solution contact unit that dissolves the coating material of the coated copper material by contact with the sulfuric acid solution to peel and remove it, and a decomposition storage tank that decomposes the coating material dissolved in the sulfuric acid solution using an electrolytic sulfuric acid solution, electrolysis in an electrolysis unit that electrolyzes the sulfuric acid solution, and liquid feed through an electrolysis circulation path that circulates the sulfuric acid solution between the decomposition storage tank and the electrolysis unit. The program instructs the control unit to execute the following steps: feed the sulfuric acid solution in which the coating material has been dissolved in the sulfuric acid solution contact unit to the decomposition storage tank through the decomposition / regeneration liquid feed path; receive the measurement results; execute electrolysis by the electrolysis unit and liquid feed through the electrolysis circulation path until the measurement results reach a reference value; and stop electrolysis by the electrolysis unit and feed the sulfuric acid solution from the decomposition storage tank to the sulfuric acid solution contact unit through the decomposition / regeneration liquid feed path when the measurement results reach a reference value.

[0026] Another form of computer-readable recording medium storing a program is a computer-readable recording medium storing a program executed by a computer that receives measurement results from a measurement unit that measures the decomposition state of a coating material in a sulfuric acid solution containing persulfuric acid, and controls liquid feeding through a decomposition / regeneration liquid feeding path provided between a sulfuric acid solution contact unit that dissolves the coating material of the coated copper material by contact with the sulfuric acid solution to peel and remove it, and a decomposition storage tank that decomposes the coating material dissolved in the sulfuric acid solution with an electrolytic sulfuric acid solution, electrolysis in an electrolysis unit that electrolyzes the sulfuric acid solution, and liquid feeding through an electrolysis circulation path that circulates the sulfuric acid solution between the decomposition storage tank and the electrolysis unit, wherein the program causes the computer to: send the sulfuric acid solution in which the coating material has been dissolved in the sulfuric acid solution contact unit to the decomposition storage tank through the decomposition / regeneration liquid feeding path; receive the measurement results; and execute electrolysis by the electrolysis unit and liquid feeding through the electrolysis circulation path until the measurement results reach a standard. When the measurement result reaches a reference value, the electrolysis by the electrolysis unit is stopped, and the sulfuric acid solution in the decomposition storage tank is sent to the sulfuric acid solution contact unit through the decomposition / regeneration liquid sending path.

[0027] According to the present invention, by contacting the coating material of the coated copper material with a sulfuric acid solution, the coating material can be peeled off and removed from the copper material, and high-purity copper material can be recovered. The dissolved coating material is decomposed in an electrolytic sulfuric acid solution containing persulfuric acid.

[0028] FIG. 1 is a schematic cross-sectional view showing an example of an apparatus used in an embodiment of the present invention. FIG. 2 is a process flow diagram illustrating an embodiment of the method for stripping and removing an insulating film and the method for regenerating a stripping solution of the present invention. FIG. 3 is a schematic cross-sectional view showing an example of an apparatus used in another embodiment. FIG. 4 is a flowchart showing the procedure of an electrolysis and regeneration process in another embodiment. FIG. 5 is a flowchart showing an embodiment in which an electrolytic sulfuric acid solution is used as the solution that is brought into contact with the coating material to strip and remove it. FIG. 6 is a schematic cross-sectional view showing an example of an apparatus used in another embodiment of the present invention. FIG. 7 is a process flow when a plurality of stripping tanks are prepared. FIG. 8 is a schematic cross-sectional view showing an example of an apparatus used in yet another embodiment of the present invention. FIG. 9 is a flowchart showing the procedure of a coating material stripping and electrolysis and regeneration process in yet another embodiment.

[0029] (Embodiment 1) FIG. 1 is a schematic cross-sectional view showing an example of an apparatus used in one embodiment of the present invention, and shows a treatment apparatus applicable to a method for stripping a resin coating material coated on a copper material and a method for regenerating a sulfuric acid solution after the stripping.

[0030] The copper material is preferably one with a high purity (for example, 99.96% or more), and examples thereof include wire and plate shapes, but the shape is not limited to a specific one.

[0031] The coating material may be a coating film having a small thickness relative to the surface area of ​​the copper material, and is preferably used for example with insulation and heat resistance. Examples of insulating materials include those with a high volume electrical resistivity (10 ７ The heat resistance required varies depending on the application, but in the preferred application of the present invention, the heat resistance must meet class B (130°C) or higher as specified in JIS standard C4003.

[0032] The coating material may be any of natural resins or synthetic resins, thermoplastic resins or thermosetting resins, and is not limited to a specific resin. For example, the coating material may be any of polyimide resins, polyesterimide resins, polyamideimide resins, polyurethane resins, and polyester resins. The coating material is not limited to one type, but may be multiple types, for example, layers of different materials stacked together.

[0033] The covering material may cover the entire copper material, or may cover only a portion of the copper material (in the cross-sectional or longitudinal direction). Examples of covering materials include those formed as a film on the surface of the copper material, but the thickness is not limited. In the following embodiments, a copper wire is used as the copper material.

[0034] The treatment device 1 has a treatment tank 5 that contains a sulfuric acid solution, and the treatment tank 5 immerses the resin-coated copper wire 2 in the sulfuric acid solution to strip the coating material. The treatment tank 5 corresponds to the sulfuric acid solution contact portion of the present invention.

[0035] The treatment device 1 also has an electrolytic sulfuric acid device 6 that electrolyzes a sulfuric acid solution to decompose the stripping material. The treatment tank 5 is one form of the sulfuric acid contact unit of the present invention and corresponds to an immersion contact tank. The electrolytic treatment device 6 constitutes part of the decomposition unit of the present invention and corresponds to an electrolysis unit. In this embodiment, the treatment tank 5 also serves as a decomposition storage tank in the decomposition unit.

[0036] If necessary, stirring means such as an external air pump 4 and a bubble generator 3 connected thereto may be provided within the treatment tank 5 to stir the tank. An electrolytic sulfuric acid device 6 for regenerating the sulfuric acid solution is connected to the treatment tank 5. A solution inlet path 9A and one end of a solution outlet path 9B are disposed in connection with the treatment tank 5, allowing the solution to be introduced into the treatment tank 5 and discharged from the treatment tank 5. The inlet path 9A and the outlet path 9B constitute an electrolytic circulation path.

[0037] The other ends of the solution inlet path 9A and the outlet path 9B are connected to the liquid passage of the electrolytic cell 10, and a circulation pump 8 is provided in the solution outlet path 9B. By operating the circulation pump 8 to send the solution to the electrolytic cell side, the solution is sent to the outlet path 9B, the electrolytic cell 10, the inlet path 9A, and the treatment tank 5, enabling the solution to circulate.

[0038] In the electrolytic cell 10, a solution outlet path 9B is connected to the lower end of the cell, and a solution inlet path 9A is connected to the upper end of the cell. An anode 10A and a cathode 10B are installed in the flow path between them, and a bipolar electrode 10C is installed between the anode 10A and the cathode 10B, so that the solution moves from bottom to top in the flow path between the electrodes. A DC power supply 7 for electrolysis is installed between the anode 10A and the cathode 10B.

[0039] In this embodiment, the device having bipolar electrodes has been described, but the presence or absence of bipolar electrodes is not particularly limited in this embodiment.

[0040] In this embodiment, the device shown in FIG. 1 is used, but the electrolysis method is not particularly limited, and is not limited to the device shown in FIG.

[0041] <Flowchart> FIG. 2 is a flowchart showing the steps of the resin peeling and removal method and the sulfuric acid solution decomposition and regeneration method of the present invention, which will be described below.

[0042] The method mainly includes a first step of a stripping process in which the coating material is stripped and removed from the surface of the copper wire 2 using a sulfuric acid solution, which is an acidic stripping solution, and a second step of a stripping solution regeneration process in which the sulfuric acid solution is electrolyzed to produce peroxodisulfuric acid and peroxomonosulfuric acid, which are generated by self-decomposition of the peroxodisulfuric acid, and other oxidizing agents, which are components of the coating material, react with each other to decompose the organic matter into carbon dioxide and water.

[0043] In the first stripping step (step S1), a sulfuric acid solution is placed in a treatment tank 5. The sulfuric acid solution is preferably adjusted to a sulfuric acid concentration of 85% by mass or more and a temperature within a range of 60 to 140°C. It is even more preferable to set the lower limit at 90°C and the upper limit at 100°C. The temperature of the sulfuric acid solution can be adjusted by heating it using a heater (not shown) installed in the tank. A copper wire 2 having a coating material (not shown) formed thereon is immersed in the sulfuric acid solution to bring the resin coating material into contact with the sulfuric acid solution.

[0044] Increasing the sulfuric acid concentration of the sulfuric acid solution reduces the degree of dissociation of sulfuric acid, resulting in a lower ion concentration in the solution. This results in a hydrophobic solution that can dissolve the coating material covering the copper wire. Since industrial processes cannot take a long time to strip and remove the coating material, it is desirable to set the lower limit of the sulfuric acid concentration in the sulfuric acid solution to 85.0% by mass. However, when electrolyzing the sulfuric acid solution in a later process, it is desirable to set the sulfuric acid concentration to 94.0% by mass or less from the perspective of electrolysis efficiency.

[0045] Furthermore, increasing the solution temperature of the sulfuric acid solution increases the dissolution rate. For this reason, it is desirable that the sulfuric acid solution and electrolytic sulfuric acid solution that come into contact with the insulating coating of the coating material have a temperature of 60°C or higher. For the same reason, it is desirable that it be 90°C or higher. On the other hand, if the solution temperature becomes too high, oxides are formed on the copper wire, reducing its purity and causing the copper wire to dissolve, resulting in a decrease in recovery yield. For this reason, it is desirable that the solution temperature be 140°C or lower. Furthermore, for the same reason, it is desirable that it be 100°C or lower.

[0046] Here, the sulfuric acid solution may be sulfuric acid itself or a sulfate, etc., as long as it can provide the above-mentioned sulfuric acid concentration. As for the solution for peeling and removing the coating material, a sulfuric acid solution containing persulfuric acid can be used as described below, but in this form, the action of persulfuric acid is not required, so a persulfuric acid-free solution or one with a persulfuric acid concentration of less than 0.5 g / L is used.

[0047] When the copper wire 2 coated with the coating material is immersed, the sulfuric acid solution can be appropriately agitated by sending air from an external air pump 4 to an air bubble generator 3. When the copper wire 2 coated with the coating material comes into contact with the sulfuric acid solution, the coating material is gradually peeled off and dissolved in the sulfuric acid solution.

[0048] Once the coating material has been removed from the copper wire 2, the copper wire 2 is subjected to a cleaning and drying step (step S2). In the cleaning and drying step (step S2), the copper wire 2 from which the coating material has been removed is removed from the treatment tank 5, washed with a cleaning solution (not shown), and dried. The cleaned and dried copper wire 2 can be recycled while maintaining its purity and achieving a high recovery rate. For example, the purity of the copper wire can be 99.96% or more, and the recovery rate can be 98% or more. In recycling, for example, a process can be adopted in which the recovered copper wire is melted and refined to produce a copper wire with high purity.

[0049] The sulfuric acid solution in which the coating material is dissolved is electrolyzed by the electrolytic sulfuric acid device 6 in the electrolytic sulfuric acid solution generation step (step S3). In the electrolytic sulfuric acid solution generation step, the circulation pump 8 is operated to circulate the sulfuric acid solution in the treatment tank 5 through the delivery line 9B, the electrolytic cell 10, the introduction line 9A, and the treatment tank 5. In the delivery line 9B, a cooler (not shown) or the like is provided to adjust the temperature of the sulfuric acid solution being delivered to a temperature of 20 to 60°C, which is a desirable electrolysis condition.

[0050] If the solution temperature during electrolysis is below 20°C, the diffusion rate of ions to the anode surface will be slow, and increasing the current density will cause wear on the diamond used in the electrode. On the other hand, if the temperature during electrolysis is above 60°C, adverse effects such as an increased rate of self-decomposition of the oxidant and reduction of the oxidant at the cathode will occur. Therefore, it is desirable to keep the temperature range between 20 and 60°C.

[0051] In the electrolysis cell 10, a voltage is applied between the anode 10A and the cathode 10B by the electrolysis DC power supply 7, and a current is passed between the anode 10A, the cathode 10B, and the bipolar electrode 10C to electrolyze the sulfuric acid solution flowing through the flow path, producing an electrolytic sulfuric acid solution such as peroxodisulfuric acid. The produced electrolytic sulfuric acid solution can be supplied to the treatment tank 5 via the inlet 9A, and can proceed to the sulfuric acid solution regeneration step (step S4). In the sulfuric acid solution regeneration step, the electrolytic sulfuric acid solution supplied to the treatment tank 5 is desirably heated to 60 to 140°C using a heater installed in the inlet 9A or a heater installed within the treatment tank 5 to enhance the oxidizing power. At temperatures below 60°C, the self-decomposition rate of the oxidizer is slow, and at temperatures above 140°C, the self-decomposition rate is too fast.

[0052] In the treatment tank 5 into which the electrolytic sulfuric acid solution is introduced, peroxodisulfuric acid (S ２ O ８ ２－ ), and peroxomonosulfuric acid (HSO ５ － ) and hydrogen peroxide (H ２ O ２ The persulfuric acid reacts with the organic matter, which is a component of the coating material dissolved in the sulfuric acid solution, and decomposes into carbon dioxide and water, regenerating the sulfuric acid solution. The regenerated sulfuric acid solution can be used again to strip and remove the coating material from another copper wire with a resin coating. For the decomposition of the coating material, a persulfuric acid concentration of 0.5 g / L or higher is desirable. At less than 0.5 g / L, the decomposition efficiency of the coating material is insufficient. However, because the released persulfuric acid reacts immediately with the organic matter, the persulfuric acid concentration only rises to about 5.0 g / L. Achieving a concentration above 5.0 g / L requires a large number of electrolytic cells, which is not practical from a cost perspective.

[0053] The present invention will now be explained chemically. The process in which the coating material dissolves in the electrolyzed sulfuric acid solution is a physical phenomenon in which a hydrophobic insulating coating dissolves and diffuses in the hydrophobic sulfuric acid solution, and no chemical reaction formula exists. The chemical reaction formula when a sulfuric acid solution is electrolyzed is shown below. From formula (1), when a sulfuric acid solution is electrolyzed, hydrogen sulfate ions (HSO ４ －) reacts to form peroxodisulfate (S ２ O ８ ２－ ) is produced. Also, since peroxodisulfuric acid is unstable, peroxomonosulfuric acid (HSO ５ － ) and hydrogen peroxide (H ２ O ２ ) (Equations (2) and (3)), and three types of oxidants exist in the electrolytic sulfuric acid solution. ４ － → 2H ＋ + S ２ O ８ ２－ + 2e － (1) S ２ O ８ ２－ + H ２ O → HSO ５ － + HSO ４ － (2) HSO ５ － + H ２ O → HSO ４ － + H ２ O ２ (3) Next, we will explain the reaction in which the insulating film, which is an organic material, reacts with an oxidizing agent such as peroxodisulfuric acid to decompose into carbon dioxide and water.

[0054] By generating an electrolytic sulfuric acid solution, the resin is decomposed into sulfate radicals and hydroxyl radicals as shown in formulas (4) and (5). The generated sulfate radicals and hydroxyl radicals completely oxidize and decompose the resin components in the stripping / removal solution as shown in formulas (6) and (7). S ２ O ８ ２－ → 2SO ４ － ・(4) 2SO ４ － ・ + 2H ２ O → 2HSO ４ － + 2OH・ (5) C, H + 2SO ４－ ・ → 2HSO ４ - + xCO ２ + yH ２ O (6) C, H + 2OH・ → xCO ２ + yH ２ O (7)

[0055] [Decrease in Decomposition Rate of Coating Material] The decomposition rate of insulating coating material decreases as the resin concentration in sulfuric acid solution or electrolytic sulfuric acid solution increases. The decomposition rate of coating material also decreases as the oxidizing agent concentration decreases. When an organic coating material dissolves, the electrical conductivity decreases as the concentration of the insulator organic material increases. Therefore, the organic material concentration can be estimated from the electrical conductivity to determine the decomposition rate. Direct analysis of organic material concentration is possible, but incorporating it into a device is too expensive. This method provides a simpler method. The oxidizing agent reacts with the organic material, decomposing it into carbon dioxide and water. Therefore, the balance between the oxidizing agent generation rate and the organic material dissolution rate is important. If the oxidizing agent generation rate is slower than the organic material dissolution rate, the organic material concentration in the sulfuric acid solution or electrolytic sulfuric acid solution gradually increases, and eventually the organic material no longer dissolves. Measuring the redox potential of the solution allows us to determine the amount (concentration) of the oxidizing agent and thus the decomposition rate of the coating material. Therefore, a measurement unit that measures the electrical conductivity and / or redox potential of the sulfuric acid solution is suitable for measuring the decomposition state of the sulfuric acid solution.

[0056] (Embodiment 2) Figure 3 shows an example of a treatment device 1A in which a measurement unit 11 for measuring electrical conductivity or redox potential is provided in a treatment tank 5. Electrical conductivity can be measured using a conductivity meter, and redox potential can be measured using a redox potentiometer. Note that components similar to those described above are denoted by the same reference numerals and will not be described again. With regard to electrical conductivity, as decomposition progresses, electrical conductivity increases, and when it reaches a predetermined reference value, it can be determined that decomposition has ended. With regard to redox potential, as decomposition progresses, the redox potential increases, and when it reaches a predetermined reference value, it can be determined that decomposition has ended.

[0057] The measurement results of the measurement unit 11 are received by the control unit 20 and can be used to control the electrolytic cell 10 and the circulation pump 8. That is, the control unit 20 can control each unit of the processing apparatus 1A by executing a program, and can receive the measurement results of the measurement unit 11 and control electrolysis in the electrolysis unit and liquid feeding in the electrolysis circulation path that circulates the sulfuric acid solution between the decomposition storage tank and the electrolysis unit. The program of the present invention causes the control unit 20 to operate as a computer.

[0058] The program may be stored in a portable recording medium. The control unit 20 of this embodiment has a computer-readable recording medium 21 that stores a program to be executed by a computer. The recording medium 21 can store various parameters for executing the program. The various parameters may also be stored in another recording medium. Examples of the recording medium 21 include a hard disk drive, an optical disk, a magnetic tape, a flash memory (SSD (Solid State Drive), a USB memory, a CompactFlash card, an SD card), etc., but this embodiment is not limited to a specific type of recording medium. The recording medium 21 may be fixed to the main body of the control unit 20 or may be removable, or may be connected to the control unit 20 via a network.

[0059] The operation of the electrolytic cell 10 and the operation of the circulation pump 8 continue until the measurement result of the measurement unit 11 reaches a predetermined standard. When the measurement result reaches the standard, the regeneration is completed and the operation of the electrolytic cell 10 and the circulation pump 8 can be stopped. At that time, a notification can be given via a display unit or the like, and depending on the device configuration, the sulfuric acid solution in the treatment tank 5 may be moved. These controls can be performed by the control unit 20. Note that in this embodiment, the measurement unit 11 has been described as measuring the electrical conductivity or oxidation-reduction potential of the sulfuric acid solution, but the present disclosure is not limited to this, and the configuration is not particularly limited as long as it can measure the decomposition state of the coating material in the sulfuric acid solution.

[0060] FIG. 4 is a flowchart showing the electrolytic sulfuric acid solution generation process and the regeneration process. Electrolysis is initiated based on the electrolytic sulfuric acid solution generation process, and the process proceeds to the regeneration process (steps S3 and S4). Next, measurement is performed using the measuring device 11 (step S5), and the measurement results are received by the control unit 20. The control unit 20 compares the measured value with a predetermined reference value stored in the memory unit and determines whether the measured value has reached the reference value (step S6). If the measured value has not reached the reference value (step S6, No), electrolysis and regeneration continue (go to step S3). If the measured value has reached the reference value (step S6, Yes), regeneration is considered complete, and electrolysis and operation of the circulation pump are stopped. Thereafter, the sulfuric acid solution can be reused as needed.

[0061] Third Embodiment Next, a third embodiment in which the coating material coated on the copper wire 2 is stripped and removed with a sulfuric acid solution containing persulfuric acid using the treatment device 1 will be described with reference to the flowchart of FIG.

[0062] First, the electrolytic sulfuric acid solution generation process (step S10) is carried out. The treatment tank 5 contains a sulfuric acid solution. The sulfuric acid solution in this case preferably has a sulfuric acid concentration of 80% by mass or more. The difference between the sulfuric acid solution in embodiment 1 and the electrolytic sulfuric acid solution in embodiment 2 is the presence or absence of a strong oxidizing agent. If an oxidizing agent is present, the dissolution rate increases due to its oxidizing power. Therefore, when stripping and removing a coating material using a sulfuric acid solution containing persulfuric acid, it is desirable to set the lower limit of the sulfuric acid concentration to 80% by mass or more. Furthermore, as with sulfuric acid solutions, increasing the solution temperature increases the dissolution rate, so it is desirable to set the temperature of the electrolytic sulfuric acid solution to 60°C or higher. For the same reason, 90°C or higher is desirable. On the other hand, it is possible to reduce the sulfuric acid concentration, thereby increasing the recovery rate of the copper wire.

[0063] In the electrolytic sulfuric acid solution generation process, the circulation pump 8 is operated to circulate the sulfuric acid solution in the treatment tank 5 through the delivery line 9B, the electrolytic cell 10, the introduction line 9A, and the treatment tank 5. In the delivery line 9B, a cooler (not shown) or the like is provided to adjust the temperature of the sulfuric acid solution being delivered to a temperature of 20 to 60° C. The temperature of the sulfuric acid solution contained in the treatment tank 5 may also be adjusted to this temperature.

[0064] In the electrolytic cell 10, a voltage is applied between the anode 10A and the cathode 10B by the electrolysis DC power supply 7, causing a current to flow, and the sulfuric acid solution flowing through the flow path is electrolyzed by the anode 10A, the cathode 10B, and the bipolar electrode 10C, thereby producing an electrolytic sulfuric acid solution such as peroxodisulfuric acid.

[0065] The generated electrolytic sulfuric acid solution is supplied to the treatment tank 5 via the inlet 9A. Once the sulfuric acid solution in the treatment tank 5 has been generated as the electrolytic sulfuric acid solution, the process proceeds to the resin stripping step (step S11). Electrolysis by the electrolytic sulfuric acid device 6 continues even during the resin stripping step. Note that, although the device having bipolar electrodes has been described in this embodiment, the presence or absence of bipolar electrodes is not particularly limited in this embodiment.

[0066] In this embodiment, the apparatus shown in Fig. 1 is used, but the electrolysis method is not particularly limited and is not limited to the apparatus shown in Fig. 1. For example, in each of the above embodiments, the treatment tank 5 and the electrolytic cell 10 are separately provided, but it is also possible to use a common tank to perform stripping and decomposition. However, it is more efficient to perform stripping and decomposition in separate devices (tanks).

[0067] In the coating material peeling and removal step (step S11), the copper wire 2 coated with the coating material is immersed in an electrolytic sulfuric acid solution. The temperature of the electrolytic sulfuric acid solution is preferably heated to 60° C. or higher.

[0068] The electrolyzed sulfuric acid solution comes into contact with the coating material on the copper wire 2, thereby effectively stripping and removing the coating material from the copper wire 2. The electrolytic sulfuric acid solution has a stronger oxidizing power than a sulfuric acid solution that does not contain an oxidizing agent, and therefore oxidizes the copper wire surface uniformly and thinly, thereby suppressing excessive oxidation and enabling the coating material to be stripped and removed while maintaining the purity of the copper wire.

[0069] The stripped material removed from the coated copper wire dissolves in the electrolytic sulfuric acid solution. The copper wire from which the coating material has been stripped is then subjected to a cleaning and drying process (copper wire cleaning and drying process; step S12) in the same manner as in the previous embodiment. At the same time, the dissolved components in the electrolytic sulfuric acid solution are decomposed by the oxidizing agent in the electrolytic sulfuric acid solution, and the sulfuric acid solution is regenerated (sulfuric acid solution regeneration process; step S13). According to this embodiment, the stripped and removed coating material from the copper wire and the decomposition of the coating material components dissolved in the electrolytic sulfuric acid solution can be performed simultaneously, resulting in efficient processing.

[0070] (Embodiment 4) In each of the above embodiments, the coated copper material was contacted with the sulfuric acid solution by immersing the coated copper material in the sulfuric acid solution. However, the contact between the coated material and the sulfuric acid solution can be achieved by any suitable method, such as spraying or flowing the sulfuric acid solution. Figure 6 shows a treatment device 1B in which a treatment tank 5 is provided with a nozzle 12 that sprays the sulfuric acid solution downward. The treatment tank 5 of this configuration is the sulfuric acid solution contact section in the present disclosure and corresponds to a release contact tank. Note that the same reference numerals are used for components similar to those of the above embodiments, and their description will be omitted or simplified.

[0071] A copper wire 2 coated with a coating material is placed on a stage 13 below the nozzle 12, and a sulfuric acid solution is sprayed downward from the nozzle 12 to bring the coating material into contact with the sulfuric acid solution. The coating material is stripped and removed from the copper wire 2 and transferred from the treatment tank 5A to the decomposition storage tank 14 via a feed line 15A. The stripped and removed coating material dissolves in the sulfuric acid solution. As in the above-described embodiment, this sulfuric acid solution can be electrolyzed in the electrolytic sulfuric acid device 6, decomposed with a sulfuric acid solution containing persulfuric acid, and regenerated. The regenerated sulfuric acid solution can be sent to the nozzle 12 by the feed pump 16 via a return line 15B and used in the stripping and removal process. The feed line 15A and the return line 15B form a decomposition and regeneration liquid transfer path.

[0072] (Embodiment 5) In each of the above-mentioned embodiments 1, a configuration having one treatment tank has been described, but a configuration having multiple treatment tanks may also be described. This embodiment 5 will be described with reference to Figure 7. In this embodiment, two treatment tanks, a first treatment tank 5A and a second treatment tank 5B, are provided, and one electrolytic sulfuric acid device 6 is also provided. The first treatment tank 5A and the second treatment tank 5B are each connected to the electrolytic sulfuric acid device 6 by an inlet line and an outlet line, respectively, and the first treatment tank 5A and the second treatment tank 5B can be connected to the electrolytic sulfuric acid device 6 by switching the inlet line and the outlet line. As in embodiment 1, the electrolytic sulfuric acid device 6 includes an anode, a cathode, a bipolar electrode, and an electrolysis DC power supply.

[0073] In this embodiment, a single treatment tank, e.g., a first treatment tank 5A, is used to immerse a copper wire coated with a coating material in a sulfuric acid solution to remove the coating material (see A in FIG. 7). When the decomposition rate of the coating film in the first treatment tank 5A decreases, the coating removal capacity is deemed insufficient, and the copper wire is removed. Sulfuric acid solution is circulated between the first treatment tank 5A and the electrolytic sulfuric acid device 6, and electrolytic sulfuric acid is generated in the electrolytic sulfuric acid device 6 to decompose the coating film components and regenerate sulfuric acid. Meanwhile, in the second treatment tank 5B, a sulfuric acid solution is stored in the treatment tank, and another copper wire coated with a coating film is immersed in the sulfuric acid solution to remove the coating film (see B in FIG. 7). When the solubility in the second treatment tank 5B decreases in this state, the copper wire is removed, and the solution is circulated between the first treatment tank 5A and the electrolytic sulfuric acid device 6 to decompose the coating film components and regenerate sulfuric acid. In the first treatment tank 5A, the coated copper wire is immersed in the regenerated sulfuric acid solution to remove the coating film (see C in FIG. 7).

[0074] By repeating the above procedure, multiple resins can be continuously treated without interrupting the process. While this embodiment has been described as having two treatment tanks, the number is not particularly limited, and the apparatus may have two or more electrolytic sulfuric acid devices. A specific form of apparatus for carrying out the coating material stripping method includes providing multiple tanks for stripping and removing the coating material, and terminating the coating material stripping and removal in a given tank according to a decrease in the decomposition rate of the coating material in that tank, and electrolyzing the sulfuric acid solution in that tank. Upon completion of the coating material stripping and removal, stripping and removal of the coating material in another tank can be continued or started.

[0075] (Embodiment 6) Next, another embodiment will be described with reference to Fig. 8. Note that the same components as those in the above embodiments are denoted by the same reference numerals, and their description will be omitted or simplified. <Flowchart> Fig. 9 is a flowchart showing the procedure for peeling and removing the coating material using a sulfuric acid solution, and for decomposing and regenerating the coating material using the sulfuric acid solution. This embodiment will be described below with reference to the flowchart.

[0076] The treatment device 1C includes multiple treatment tanks (treatment tanks 50A, 50B, 50C, and 50D) that contain sulfuric acid solution and in which the coated copper material is immersed. The treatment tanks 50A, 50B, 50C, and 50D also include a decomposition storage tank 30 that contains the sulfuric acid solution in which the coating resin is dissolved, and an electrolytic sulfuric acid device 6. The treatment tanks 50A, 50B, 50C, and 50D correspond to the sulfuric acid contact unit and immersion contact tank of the present disclosure. A measurement unit 11 is disposed in the decomposition storage tank 30 and is immersed in the sulfuric acid solution to measure the electrical conductivity or redox potential of the sulfuric acid solution.

[0077] Between the treatment tanks 50A, 50B, 50C, and 50D and the decomposition storage tank 30, there is an outlet path 29A that sends the sulfuric acid solution treated in the treatment tank to the decomposition storage tank 30, and an inlet path 29B that sends the sulfuric acid solution regenerated in the decomposition storage tank 30. The outlet path 29A is provided with a liquid feed pump 32A, and the inlet path 29B is provided with a liquid feed pump 32B. Furthermore, the inlet path 29B is provided with a heating unit 28 that heats the sulfuric acid solution to be sent. The outlet path 29A and the inlet path 29B branch off and are connected to the treatment tanks 50A, 50B, 50C, and 50D, respectively. The outlet path 29A and the inlet path 29B constitute the decomposition / regeneration liquid feed paths of the present disclosure.

[0078] In addition, between the decomposition storage tank 30 and the electrolytic sulfuric acid device 6, there are provided an inlet line 31A for feeding the sulfuric acid solution from the electrolytic sulfuric acid device 6 to the decomposition storage tank 30, and an outlet line 31B for feeding the sulfuric acid solution from the decomposition storage tank 30 to the electrolytic sulfuric acid device 6. The inlet line 31B is provided with a circulation pump 33 and a cooling unit 34 for cooling the sulfuric acid solution. In addition, there is provided a control unit 20 that receives the measurement results of the measurement unit 11 and controls the operation of the liquid feed pumps 32A, 32B and the circulation pump 33.

[0079] In this embodiment, the control unit 20 controls each part of the processing device 1C by executing a program, and upon receiving the measurement results of the measurement unit 11, can control the liquid supply through the decomposition / regeneration liquid supply path provided between the sulfuric acid solution contact unit and the decomposition storage tank in which the coating material dissolved in the sulfuric acid solution is decomposed by the electrolytic sulfuric acid solution, the electrolysis in the electrolysis unit, and the liquid supply through the electrolysis circulation path that circulates the sulfuric acid solution between the decomposition storage tank and the electrolysis unit.

[0080] The control unit 20 of this embodiment has a computer-readable recording medium 21 that stores a program to be executed by a computer. The recording medium 21 stores various parameters for executing the program. The recording medium 21 may be a hard disk drive, an optical disk, a magnetic tape, a flash memory (SSD (Solid State Drive), a USB memory, a CompactFlash card, an SD card), or the like, but this embodiment is not limited to a specific type of recording medium. The recording medium 21 may be fixed to the main body of the control unit 20, may be removable, or may be connected to the main body of the control unit 20 via a network.

[0081] Next, the operation of the processing apparatus 1C will be described. The processing baths 50A, 50B, 50C, and 50D contain sulfuric acid solution. The sulfuric acid solution is preferably maintained at 60 to 140°C. In all or some of these processing baths 50A, 50B, 50C, and 50D, the temperature is set to an appropriate temperature. Copper wires coated with a coating material are immersed in the sulfuric acid solution, and the coating material is dissolved and peeled off (step S20). In this step, as described above, the processing baths 50A, 50B, 50C, and 50D initially contain sulfuric acid solution.

[0082] That is, in step S20, the control unit 20 can control at least one of the following steps: initially, the sulfuric acid solution is placed in the treatment tanks 50A, 50B, 50C, and 50D, and then the sulfuric acid solution is heated to a desired temperature (e.g., 60 to 140° C.) by the heating unit 28, and the coating material is immersed in all or some of the treatment tanks 50A, 50B, 50C, and 50D. Note that an electromagnetic valve may be provided in each branch of the introduction line 29B, and the control unit 20 may control the opening and closing of the electromagnetic valve to select the treatment tank to which the solution is to be sent.

[0083] In the treatment tank in which the coated copper wire is immersed, the dissolution state is determined (step S21). While this determination may be made visually or based on the elapsed time, an appropriate dissolution measurement unit, such as a solution permeability measurement unit, may be used. The results are received by the control unit 20, and the control unit 20 compares the results with a dissolution reference value to determine the completion of stripping. In this embodiment, stripping completion is determined based on a set elapsed time after stripping begins. The elapsed time until stripping completion can be determined in advance through a similar process. If stripping completion is determined (step S21, YES), in any of the treatment tanks 50A, 50B, 50C, and 50D in which the coated copper wire is immersed and stripping is complete, the sulfuric acid solution in which the coating material has dissolved is sent to the decomposition storage tank 30 via the delivery path 29A by the liquid delivery pump 32A. If stripping completion is determined not to be reached in step S21 (step S21, NO), the stripping process in step S20 continues. The dissolution reference value and other information used for the determination are stored in the recording medium 21 or the like and are read and used for the determination when the program is executed. In this case, the control unit 20 can control the opening and closing of the electromagnetic valves of each branch path and the liquid sending pump 32A to send the liquid.

[0084] When the sulfuric acid solution in which the coating material is dissolved is stored in the decomposition storage tank 30, the circulation pump 33 is operated to circulate the sulfuric acid solution H ２ SO ４ The sulfuric acid solution is electrolyzed while circulating between the decomposition storage tank 30 and the electrolytic sulfuric acid device 6 (step S23). During circulation, the sulfuric acid solution sent from the decomposition storage tank 30 is cooled (for example, 20 to 60°C) by the cooling unit 34 provided in the delivery line 31B. Persulfuric acid H ２ S ２ O ８ is generated and sent to decomposition storage tank 30 via inlet line 31A and heating unit 35. At this time, the persulfuric acid concentration is desirably 0.5 to 5.0 g / L, and it is desirably heated to 60 to 140°C by heating unit 35. These controls can be performed by control unit 20, and each parameter can use data stored in advance in recording medium 21 or the like, and the program can read these parameters to control electrolysis, the temperature of the sulfuric acid solution, and the solution feed.

[0085] In the decomposition storage tank 30, the components of the coating material dissolved in the sulfuric acid solution are gradually decomposed by the sulfuric acid solution containing persulfuric acid introduced. By continuing the above-described operation, the concentration of the coating material dissolved in the sulfuric acid solution gradually decreases. The decomposition status of the coating material in the sulfuric acid solution is measured by the measurement unit 11 and transmitted to the control unit 20. The control unit 20 determines whether the measurement result reaches a reference value. If the reference value is not reached, circulation of the sulfuric acid solution and electrolysis continue (step S24, NO). In this embodiment, completion of decomposition is determined based on the measured value of electrical conductivity or redox potential. If the measured value reaches the reference value, decomposition is determined to be complete, and application of voltage to the electrolytic treatment device 6 is stopped, and operation of the circulation pump 33 is stopped (step S24, YES). The reference value is pre-stored in the recording medium 21 or the like and can be read and used for determination by the control unit 20.

[0086] If it is determined in step S24 that the decomposition is complete, the liquid supply pump 32B is operated to supply the sulfuric acid solution in the decomposition storage tank 30 to any or all of the treatment tanks 50A, 50B, 50C, and 50D (step S25), making it possible to reuse the sulfuric acid solution for stripping and removing coated copper material. After step S25, the treatment can be terminated at an appropriate time or a predetermined time, but if it is not terminated, the process proceeds to step S20, and the procedures from the stripping treatment for a new coated copper wire are repeated.

[0087] As described above, parameters such as the reference values ​​in the control unit 20 may be set in advance and stored in a nonvolatile memory unit, or may be acquired from a server or the like via a network or the like. Different values ​​may be set as the reference values ​​depending on the type of coating material, etc. The regenerated sulfuric acid solution may be used for purposes other than the same purpose.

[0088] In the above embodiment, the peeling and regeneration treatment of the coated copper material was described without specifying a treatment bath, but these treatments may be performed simultaneously in multiple treatment baths, or sequentially. By performing the treatment sequentially in multiple treatment baths, efficient treatment can be achieved without waste.

[0089] Although the present invention has been described above based on the above embodiment, appropriate modifications are possible without departing from the scope of the present invention. The resin-coated copper wire to be treated in this embodiment is generally referred to as magnet wire. The resin of the insulating coating coating that coats the copper wire may be, for example, any of polyimide resin, polyesterimide resin, polyamideimide resin, polyurethane resin, and polyester resin, and is not limited to a specific resin. Furthermore, the resin-coated copper wire may be in any shape, such as a rectangular wire or a round wire, and may be treated not only as a single resin-coated copper wire but also in a coiled state, for example. This embodiment is suitable for use in a method for peeling and removing an insulating coating from a resin-coated copper wire, which is a copper wire for winding electronic devices used in automobiles, home appliances, industrial applications, etc., and recovering the copper wire. However, the applications of this embodiment are not limited to these applications.

[0090] (Examples 1 and 3) In Examples 1 and 3, a coating film stripping treatment was performed using a sulfuric acid solution. In Example 1, the sulfuric acid solution was 94.0 mass %, the solution temperature was 100°C, and the oxidant concentration was 0.1 g / L, while in Example 3, the coating film stripping treatment was performed using a sulfuric acid solution of 90.0 mass %, the solution temperature was 110°C, and the oxidant concentration was 0.2 g / L. After visually determining the completion of the treatment, the copper purity and the copper remaining rate after the treatment were determined. In order to visually determine the completion of the treatment, a standard chart was created that lists the surfaces of various magnet wires treated for different times and the results of an analysis device to check for the presence or absence of an insulating coating.

[0091] [Conditions for peeling treatment test pieces] Test pieces were cut to a length of approximately 150 mm from magnet wires having polyimide insulating coatings with different peeling conditions. The same applies to the following: - Copper wire cross-sectional dimensions: 1.47 mm x 2.93 mm - Insulating coating cross-sectional dimensions: 1.68 mm x 3.14 mm - Nominal coating thickness: 102.5 μm [Specifications for peeling treatment tank] - Volume of treatment tank 5: 25 L

[0092] (Examples 2, 4, 5) In Examples 2, 4, and 5, the coating film removal treatment was performed using an electrolytic sulfuric acid solution. In Example 2, the sulfuric acid solution was 94.0 mass%, the solution temperature was 100 ° C, and the oxidant concentration was 0.5 g / L. In Example 4, the sulfuric acid solution was 90.0 mass%, the solution temperature was 110 ° C, and the oxidant concentration was 2.0 g / L. In Example 5, the coating film treatment was performed using an 80.0 mass% sulfuric acid solution, the solution temperature was 120 ° C, and the oxidant concentration was 5.0 g / L. [Generation of electrolytic sulfuric acid solution] The treatment conditions for electrolyzing the sulfuric acid solution are as follows. - Material of anode 10A and cathode 10B: diamond electrode (diameter 150 mm) - Material of bipolar electrode 10C: diamond electrode (diameter 150 mm) - Current density: 5 to 30 A / dm ２ Electrolysis cell circulation flow rate: 2 to 3 L / min

[0093] Comparative Example 1: A coating treatment was carried out using an alkaline stripping solution containing potassium hydroxide, monoethanolamine, and phosphoric acid as the main components, at 95° C. The amount of the treatment solution was 1 L. The test pieces and other materials used were the same as those used in Example 1.

[0094]

[0095] The oxidizing agent concentration in each test example was determined by taking a portion of the electrolyzed solution, subjecting the solution to a starch iodide reaction, and neutralizing titrating the solution to determine its total oxidizing power (KI value). The solution was also titrated with potassium permanganate to measure the amount of hydrogen peroxide in the solution, and the measured value was subtracted from the KI value to determine the oxidizing power of the solution.

[0096] In Reference Example 1, treatment was performed under the conditions of Example 1 for the same time as in Example 2. Although the stripping process progressed, it was found that the insulating film could not be completely removed within the set treatment time (the same time as in Example 2), and a longer treatment time was required. It was also found that the stripping and removal of the insulating film could be performed more efficiently in a sulfuric acid solution containing persulfuric acid, as in Examples 2, 4, and 5. Furthermore, in Reference Example 2, the treatment was performed with a sulfuric acid concentration lower than the desired value. Although the stripping process progressed, the treatment could not be completed within the 180-minute treatment time, so the treatment was interrupted after the 180-minute treatment time. It was found that the treatment efficiency decreased when the sulfuric acid concentration was lower than the desired value. In Reference Examples 1 and 2, the stripping and removal of the film was not completed, so the Cu purity and Cu residual rate were not measured.

[0097] 1 Processing device 1A Processing device 1B Processing device 1C Processing device 2 Copper wire 3 Bubble generator 4 Air pump 5 Processing tank 5A First processing tank 5B Second processing tank 6 Electrolytic sulfuric acid device 7 Electrolysis DC power supply 8 Circulation pump 9A Inlet line 9B Outlet line 10 Electrolytic cell 10A Anode 10B Cathode 10C Bipolar electrode 11 Measuring unit 12 Nozzle 14 Decomposition storage tank 15A Feed line 15B Return line 16 Liquid feed pump 20 Control unit 21 Recording medium 28 Heating unit 29A Outlet line 29B Inlet line 30 Decomposition storage tank 31A Inlet line 31B Outlet line 32A Liquid feed pump 32B Liquid feed pump 33 Circulation pump 34 Cooling unit 50A Processing tank 50B Treatment tank 50C Treatment tank 50D Treatment tank

Claims

1. A method for stripping a coated copper material, comprising contacting a coating material coated on a copper material with a sulfuric acid solution, dissolving the coating material in the sulfuric acid solution, and stripping and removing the coating material from the copper material, and then decomposing the coating material dissolved in the sulfuric acid solution with an electrolytic sulfuric acid solution containing persulfuric acid.

2. The method for stripping coated copper materials according to claim 1, wherein the concentration of persulfuric acid in the electrolytic sulfuric acid solution is 0.5 g / L or more.

3. A stripping method according to claim 1 or 2, wherein the sulfuric acid solution used to decompose the coating material is reused for stripping and removing the coated copper material or other coated copper materials.

4. A stripping treatment method according to claim 1 or 2, wherein the sulfuric acid solution brought into contact with the coating material covering the copper material has a persulfuric acid concentration of less than 0.5 g / L, a sulfuric acid concentration of 85.0 mass% or more, and a temperature within the range of 60 to 140°C.

5. The stripping treatment method according to claim 1, wherein the sulfuric acid solution brought into contact with the coating material covering the copper material is an electrolytic sulfuric acid solution having a persulfuric acid concentration of 0.5 g / L or more during part or all of the stripping and removal process, and the sulfuric acid concentration is 80.0 mass % or more and the temperature is within the range of 60 to 140°C.

6. A stripping treatment method according to claim 1 or 5, wherein the electrolytic sulfuric acid solution is electrolyzed at a solution temperature of 20 to 60°C.

7. A stripping method according to claim 5 or 6, wherein the decomposition state of the coating material is determined by one or both of the electrical conductivity and the oxidation-reduction potential of the sulfuric acid solution.

8. A stripping method according to claim 7, wherein when the decomposition state of the coating material reaches a standard, it is determined that regeneration is complete, and the regenerated sulfuric acid solution is used to strip and remove the coated copper material.

9. A peeling and removal treatment device having a sulfuric acid solution contact section that brings the coating material of the coated copper material into contact with a sulfuric acid solution, and a decomposition section that decomposes the coating material dissolved in the sulfuric acid solution with an electrolytic sulfuric acid solution.

10. A peeling and removal treatment device as described in claim 9, wherein the sulfuric acid solution contact section has one or both of an immersion treatment tank in which the coated copper material is immersed in the sulfuric acid solution and a release contact tank in which the sulfuric acid solution is released onto the coated material to bring it into contact with the coated material.

11. The peeling and removal treatment device according to claim 9 or 10, wherein the decomposition section is provided with an electrolysis section for electrolyzing a sulfuric acid solution.

12. The peeling and removal treatment device according to claim 11, wherein a plurality of the sulfuric acid solution contact sections are provided, and one or more of the electrolysis sections are capable of selectively electrolyzing the sulfuric acid solutions of the plurality of sulfuric acid solution contact sections.

13. A peeling and removal treatment device according to claim 9 or 10, wherein the decomposition section comprises a decomposition storage tank and an electrolysis section, and an electrolysis circulation path for circulating sulfuric acid solution between the decomposition storage tank and the electrolysis section.

14. The peeling and removal treatment device according to claim 13, further comprising a decomposition and regeneration liquid transfer path between the sulfuric acid solution contact section and the decomposition storage tank.

15. A peeling and removal processing device as described in claim 14, comprising a measurement unit that measures the decomposition state of the sulfuric acid solution in the decomposition unit, and a control unit that controls the electrolysis in the electrolysis unit and the liquid supply through the electrolysis circulation path and the decomposition / regeneration liquid supply path, wherein the control unit receives the measurement results of the measurement unit and determines the content of the control based on the measurement results.

16. A processing device having a measuring unit that measures the decomposition state of a coating material in a sulfuric acid solution containing persulfuric acid, a sulfuric acid solution contact unit that dissolves the coating material of the coated copper material by contact with the sulfuric acid solution to peel and remove it, a decomposition storage tank that decomposes the coating material dissolved in the sulfuric acid solution using an electrolytic sulfuric acid solution, a decomposition / regeneration liquid supply path provided between the sulfuric acid solution contact unit and the decomposition storage tank, an electrolysis unit that electrolyzes the sulfuric acid solution, and an electrolysis circulation path that circulates the sulfuric acid solution between the decomposition storage tank and the electrolysis unit, wherein the processing device control unit receives the measurement results from the measuring unit and controls the electrolysis in the electrolysis unit and the liquid supply through the electrolysis circulation path and the decomposition / regeneration liquid supply path, and receives the measurement results and performs control to determine the content of the control based on the measurement results.

17. A program executed by a control unit that receives measurement results from a measurement unit that measures the decomposition state of a coating material in a sulfuric acid solution containing persulfuric acid, and controls the liquid feed through a decomposition / regeneration liquid feed path provided between a sulfuric acid solution contact unit that dissolves the coating material of a coated copper material by contact with the sulfuric acid solution to peel and remove it, and a decomposition storage tank that decomposes the coating material dissolved in the sulfuric acid solution with an electrolytic sulfuric acid solution, electrolysis in an electrolysis unit that electrolyzes the sulfuric acid solution, and liquid feed through an electrolysis circulation path that circulates the sulfuric acid solution between the decomposition storage tank and the electrolysis unit, wherein the program receives measurement results from a measurement unit that measures the decomposition state of a coating material in a sulfuric acid solution containing persulfuric acid, and controls the liquid feed through a decomposition / regeneration liquid feed path provided between the measurement unit and a decomposition storage tank that dissolves the coating material dissolved in the sulfuric acid solution with an electrolytic sulfuric acid solution, the program causes the control unit to execute the following steps: feed the sulfuric acid solution in which the coating material has been dissolved in the sulfuric acid solution contact unit to the decomposition storage tank through the decomposition / regeneration liquid feed path; receive the measurement results; execute electrolysis by the electrolysis unit and liquid feed through the electrolysis circulation path until the measurement results reach a reference value; and stop electrolysis by the electrolysis unit when the measurement results reach a reference value, and feed the sulfuric acid solution from the decomposition storage tank to the sulfuric acid solution contact unit through the decomposition / regeneration liquid feed path.

18. A computer-readable recording medium storing a program executed by a computer that receives measurement results from a measurement unit that measures the decomposition state of a coating material in a sulfuric acid solution containing persulfuric acid, and controls liquid delivery through a decomposition / regeneration liquid delivery path provided between a sulfuric acid solution contact unit that dissolves the coating material of the coated copper material by contact with the sulfuric acid solution to peel and remove it, and a decomposition storage tank that decomposes the coating material dissolved in the sulfuric acid solution with an electrolytic sulfuric acid solution, electrolysis in an electrolysis unit that electrolyzes the sulfuric acid solution, and liquid delivery through an electrolysis circulation path that circulates the sulfuric acid solution between the decomposition storage tank and the electrolysis unit, wherein the program instructs the computer to: deliver the sulfuric acid solution in which the coating material has been dissolved in the sulfuric acid solution contact unit to the decomposition storage tank through the decomposition / regeneration liquid delivery path; receive the measurement results; and execute electrolysis by the electrolysis unit and liquid delivery through the electrolysis circulation path until the measurement results reach a standard. When the measurement result reaches a reference value, the electrolysis by the electrolysis unit is stopped, and the sulfuric acid solution in the decomposition storage tank is sent to the sulfuric acid solution contact unit via the decomposition / regeneration liquid sending path.

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