High-stable sulfuric acid-hydrogen peroxide copper plating stripping agent

Abstract

The application discloses a high-stability sulfuric acid-hydrogen peroxide copper plating stripping agent, which is composed of hydrogen peroxide, sulfuric acid, molybdenum-tin heteropoly acid complex stabilizer, pH responsive corrosion inhibitor and pure water; the content of each component is as follows: 8-12% of hydrogen peroxide, 10-20% of sulfuric acid, 5.5-6.5 g / L of molybdenum-tin heteropoly acid complex stabilizer, 1-1.4 g / L of pH responsive corrosion inhibitor, and the rest is pure water. The application optimizes the components and the ratio of the sulfuric acid-hydrogen peroxide copper plating stripping agent, solves the defects of poor environmental protection, insufficient stability, easy tank overturning and substrate corrosion of the traditional stripping system, realizes stable and efficient stripping of the copper layer, prolongs the service life of the chemical solution, reduces the processing cost and the work safety hazard, is suitable for the scene of high substrate protection requirement such as composite foil, and helps to improve the performance of the battery current collector.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and specifically to a highly stable sulfuric acid-hydrogen peroxide copper plating stripping agent. Background Technology

[0002] With the rapid development of new energy and electronic technology, battery cycle life, safety performance, and energy density have become top priorities in the industry. As a core component of the battery, the current collector plays a crucial role in collecting the current generated by the battery's active materials to form a larger output current. Its performance directly determines the battery's cycle life, energy density, and safety. Currently, copper and aluminum foils are commonly used as current collectors for the positive and negative electrodes of lithium and sodium batteries. These traditional foil materials suffer from high cost and weight, hindering cost control and energy density improvement. Against this backdrop, composite foil current collectors are gradually replacing traditional foils due to their significant advantages. These current collectors often have a "sandwich" structure, with an inner polymer layer as the base and metal conductive layers on both sides. Compared to traditional foil materials, functional current collectors have a thinner surface metal layer and a lighter inner polymer layer. This effectively reduces the overall weight of the current collector, thereby increasing the energy density of lithium-ion batteries. Furthermore, in the event of thermal runaway, the thin surface metal layer quickly disconnects the connection between the active materials and the current collector, preventing further spread of thermal runaway and ensuring battery safety. Meanwhile, in existing copper plating processes, copper layers easily deposit on the surface of the fixtures, requiring periodic stripping treatment. Traditional nitric acid-based stripping agents have many drawbacks, including severe acid mist volatilization that harms the operating environment, unstable copper layer dissolution rates that easily lead to over-corrosion risks, and high concentrations of heavy metals and nitrates in the waste liquid, resulting in high subsequent treatment costs. The organic corrosion inhibitor + hydrogen peroxide system currently used in the industry also has significant shortcomings. This system has extremely poor chemical stability, hydrogen peroxide is prone to decomposition leading to a shelf life of less than 7 days, and frequent tank overflows caused by the tank temperature rising to 100°C, which not only damages production pipelines but also poses serious industrial safety hazards. Therefore, the development of a high-efficiency, stable, and environmentally friendly copper plating stripping agent and related technologies has become an urgent need for the industry. Summary of the Invention

[0003] To address the shortcomings of existing copper plating stripping agents, such as poor stability, uneven stripping efficiency, poor environmental performance, and potential industrial safety hazards, as well as the poor compatibility of traditional stabilizers, this invention provides a method and apparatus for using a highly stable sulfuric acid-hydrogen peroxide copper plating stripping agent. The aim is to achieve long-term stability of the stripping agent, controllable stripping efficiency, environmental friendliness, and no industrial safety hazards. It is also suitable for applications requiring high substrate protection, such as composite copper foil, thus overcoming many deficiencies of existing technologies.

[0004] To achieve the above objectives, the technical solution provided by the present invention is as follows: The first aspect of this invention provides a highly stable sulfuric acid-hydrogen peroxide copper plating stripping agent, wherein the stripping agent is composed of hydrogen peroxide, sulfuric acid, a molybdenum-tin heteropoly acid complex stabilizer, a pH-responsive corrosion inhibitor, and pure water; The contents of each component are as follows: hydrogen peroxide 8~12%, sulfuric acid 10~20%, molybdenum-tin heteropolyacid complex stabilizer 5.5~6.5g / L, pH-responsive corrosion inhibitor 1~1.4g / L, and the remainder is pure water.

[0005] To optimize the above technical solution, the specific limitations also include: Furthermore, the molybdenum-tin heteropolyacid complex stabilizer is a compound of silicotungstic acid and sodium stannate in a molar ratio of 1:1.1~1.3.

[0006] The pH-responsive corrosion inhibitor is activated to accelerate peeling when pH < 1 and automatically passivates to form protection when pH > 3.

[0007] Preferably, the pH-responsive corrosion inhibitor is methylbenzimidazole-propanesulfonic acid inner salt.

[0008] No temperature control is required during the peeling and hanging process.

[0009] Using this stripping agent, the copper layer stripping rate is stable at 15~25 μm / min at room temperature.

[0010] The solution stability of the stripping agent is more than 3 months, and the decomposition rate of hydrogen peroxide is less than 5% after 72 hours.

[0011] The aforementioned stripping agent is used in conjunction with a stripping tank equipped with circulation and filtration functions.

[0012] The second aspect of the present invention provides a method for treating a functional current collector, wherein the above-mentioned highly stable sulfuric acid-hydrogen peroxide copper plating stripping agent is used to perform stripping treatment on the functional current collector after copper plating.

[0013] The functional current collector contains a polymer base film layer and copper layers on both sides, wherein the copper layers include an inner magnetron sputtered copper layer and an outer electroplated copper layer.

[0014] Compared with the prior art, the beneficial effects of the present invention are: This invention significantly reduces the hydrogen peroxide decomposition rate of the traditional hydrogen peroxide system by adding a molybdenum-tin heteropoly acid complex stabilizer and a pH-responsive corrosion inhibitor. The decomposition rate is reduced from >40% in the traditional system to <5% in the traditional system after 72 hours. Under accelerated testing at 40°C, the stability period of the stripping solution is no less than 3 months, and under sealed storage at room temperature, the shelf life is no less than 6 months. During storage, there is no significant decomposition of the components or precipitation, thus completely solving the problem of short shelf life of existing stripping solutions.

[0015] At room temperature of 25℃, the copper layer peeling rate is stable at 15~25μm / min, and the formula can be flexibly adjusted according to the needs. This stripping agent can peel off copper deposits with a thickness of 5~50μm. After peeling, there is no copper layer residue or scratches on the surface of the fixture, and it will not damage the substrate. It is suitable for scenarios with high requirements for substrate protection, such as composite copper foil.

[0016] The hydrogen peroxide decomposition rate in this stripping agent is controllable, with no significant exothermic reaction, effectively preventing the tank temperature from rising above 60°C. It eliminates the need for tank turnovers, completely resolving the problems of tank turnovers and pipeline damage in existing systems. This stripping agent does not contain nitric acid or ammonia nitrogen, resulting in no high concentrations of nitrate in the stripping wastewater, making wastewater treatment easier and less costly. Furthermore, copper ions in the wastewater can be recovered through simple chemical precipitation, further reducing environmental treatment costs and meeting industry environmental development requirements.

[0017] The compounding process of the molybdenum-tin heteropolyacid complex stabilizer does not require the addition of an additional catalyst and can be completed by stirring at room temperature, simplifying the preparation process; all components are conventional chemical raw materials, which are easy to obtain, can effectively control production costs, and facilitate large-scale industrial application.

[0018] The formulation of the stripping agent of the present invention can be finely adjusted within a preset range to adapt to different scenarios with different stripping efficiency requirements; the stripping method is simple to operate, requires no complex process control, and the adapted stripping device has a simple structure and is easy to maintain. It can be directly adapted to existing electroplating production lines without large-scale equipment modification, thus reducing production investment; it is suitable for various scenarios such as composite copper foil, precision electronic electroplating, and automotive parts electroplating. Detailed Implementation

[0019] The present invention will be further described in detail below through specific embodiments, but it should not be construed as limiting the scope of the subject matter of the present invention to the following embodiments. All technologies implemented based on the above content of the present invention fall within the scope of the present invention.

[0020] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the reagents, methods and equipment used are conventional reagents, methods and equipment in this technical field.

[0021] This invention provides a highly stable sulfuric acid-hydrogen peroxide copper plating stripping agent, which is composed of hydrogen peroxide, sulfuric acid, molybdenum-tin heteropoly acid complex stabilizer, pH-responsive corrosion inhibitor and pure water; The contents of each component are as follows: hydrogen peroxide 8~12%, sulfuric acid 10~20%, molybdenum-tin heteropolyacid complex stabilizer 5.5~6.5g / L, pH-responsive corrosion inhibitor 1~1.4g / L, and the remainder is pure water.

[0022] This invention solves the problems of traditional nitric acid stripping agents, such as severe acid mist volatilization, environmental damage, high risk of over-corrosion, and high wastewater treatment costs, by combining hydrogen peroxide, sulfuric acid, molybdenum-tin heteropoly acid complex stabilizer, and pH-responsive corrosion inhibitor. It also overcomes the problems of existing organic corrosion inhibitor + hydrogen peroxide systems, such as instability, easy decomposition of hydrogen peroxide, short shelf life, easy tank temperature rise and tank overflow, and potential safety hazards. The resulting stripping agent is free of nitric acid and ammonia nitrogen, has excellent environmental performance, and is easy to treat wastewater. It is suitable for applications requiring high substrate protection, such as composite copper foil and precision electronic electroplating, balancing stripping efficiency, solution stability, and environmental friendliness, providing a long-term and stable solution for removing residual copper from electroplating fixtures.

[0023] Compared to traditional single stabilizers such as stannates and sodium pyrophosphates, the molybdenum-tin heteropolyacid complex stabilizer of this invention can significantly improve the stability of hydrogen peroxide, effectively inhibit the decomposition of hydrogen peroxide, and optimize the uniformity of copper layer peeling, thus avoiding the problem of poor performance when single stabilizers are applied to composite copper foil scenarios.

[0024] In some embodiments, the molybdenum-tin heteropolyacid complex stabilizer is a mixture of silicotungstic acid and sodium stannate in a molar ratio of 1:1.1~1.3.

[0025] The pH-responsive corrosion inhibitor activates to accelerate stripping when pH < 1 and automatically passivates to form a protective layer when pH > 3. The pH-responsive characteristics of the inhibitor include: activating accelerated stripping when pH < 1, enabling rapid and efficient stripping of the copper deposit on the fixture surface, ensuring stripping efficiency and meeting the needs of industrial production; and automatically passivating to form a protective layer when pH > 3, effectively preventing excessive corrosion of the substrate during stripping. This is particularly suitable for scenarios with high substrate protection requirements, such as composite copper foil, solving the shortcomings of traditional stripping agents that cannot balance stripping efficiency and substrate protection. It ensures thorough copper layer stripping while protecting the integrity of the substrate, and reduces product loss due to substrate corrosion.

[0026] In some embodiments, the pH-responsive corrosion inhibitor is methylbenzimidazole-propanesulfonic acid inner salt. Compared with traditional corrosion inhibitors such as benzotriazole, this corrosion inhibitor has higher pH response sensitivity and better corrosion inhibition effect. At the same time, this corrosion inhibitor has excellent compatibility with other components in the stripping agent and will not produce adverse reactions, further improving the overall stability and safety of the stripping agent.

[0027] No temperature control is required during the peeling and hanging process. Compared with the existing peeling and hanging process that requires strict temperature control, the production process is greatly simplified, the production energy consumption and operation difficulty are reduced, and problems such as accelerated hydrogen peroxide decomposition, tank temperature rise and tank turnover, and unstable peeling and hanging rate caused by improper temperature control are avoided.

[0028] Using this stripping agent, the copper layer stripping rate remains stable at 15–25 μm / min at room temperature. This rate range meets the requirements of rapid stripping in industrial production, ensuring production efficiency, while avoiding problems such as substrate corrosion and uneven copper layer stripping caused by excessively fast stripping rates. Compared to traditional stripping agents, the stripping efficiency is significantly improved, greatly shortening the production cycle and increasing production capacity. Furthermore, the stable rate range with minimal fluctuations ensures consistent stripping results in mass production, reducing product quality variations. The solution stability of the described stripping agent is over 3 months, with a hydrogen peroxide decomposition rate of <5% within 72 hours. Compared to existing hydrogen peroxide-based stripping agents (storage period <7 days, hydrogen peroxide decomposition rate >40% within 24 hours), the stability improvement is extremely significant, completely solving the problems of rapid solution failure, frequent tank solution replacement, low production efficiency, large waste discharge, and high treatment costs caused by the easy decomposition of hydrogen peroxide in existing stripping agents.

[0029] Preferably, the stripping agent is used in conjunction with a stripping tank equipped with circulation and filtration functions. The circulation function ensures uniform distribution of the components of the stripping agent, avoiding problems such as uneven stripping rates and accelerated hydrogen peroxide decomposition caused by excessively high or low concentrations of local components, further improving the consistency of the stripping effect and the stability of the solution. The filtration function can promptly remove copper impurities generated during the stripping process, preventing impurity deposition from affecting the stripping efficiency and substrate protection effect, reducing the damage of impurities to the components of the stripping agent, and extending the service life of the stripping agent.

[0030] The present invention also provides a method for treating functional current collectors, wherein the above-mentioned highly stable sulfuric acid-hydrogen peroxide copper plating stripping agent is used to perform stripping treatment on the functional current collector after copper plating.

[0031] The functional current collector contains a polymer base film layer and copper layers on both sides. The copper layers include an inner magnetron sputtered copper layer and an outer electroplated copper layer.

[0032] Applying a highly stable sulfuric acid-hydrogen peroxide copper plating stripping agent to the stripping treatment of functional current collectors after copper plating solves the problems of poor compatibility, ineffective stripping, easy corrosion of substrates, poor environmental performance, and low safety associated with traditional stripping methods. This method can quickly and efficiently remove residual copper from the surface of the fixture during the copper plating process of functional current collectors without damaging the substrate, thus ensuring product quality. Furthermore, this treatment method is simple, requires no temperature control, and exhibits high stability, making it suitable for large-scale industrial production. Combined with the characteristics of functional current collectors, this method better leverages the advantages of the stripping agent, balancing stripping efficiency and substrate protection, providing a reliable post-treatment guarantee for the large-scale production of functional current collectors. The technical solution of the present invention will be further described in detail below with reference to specific embodiments: Example 1: 1. Experimental conditions At room temperature (25℃), the base film of the functional current collector is a 4μm thick polypropylene film, the transition layer is a 1μm thick magnetron copper layer, and the surface metal layer is a 1μm thick copper layer; the copper deposition layer on the surface of the electroplating fixture is 25μm thick; the stripping device is a 500L stripping tank with circulation and filtration functions, and operates without temperature control.

[0033] 2. Preparation of stripping agent Prepare a 500L stripping solution with the following components and concentrations: 12% hydrogen peroxide, 20% sulfuric acid, 6g / L molar ratio of molybdenum-tin heteropolyacid complex stabilizer (silicotungstic acid to sodium stannate molar ratio 1:1.2, mixed at room temperature with stirring), 1.2g / L methylbenzimidazole-propanesulfonic acid inner salt, and the remainder being pure water. Preparation process: First, add the pre-set amount of pure water to the stripping tank, then slowly add sulfuric acid and hydrogen peroxide in sequence. After stirring evenly, add the molybdenum-tin heteropolyacid complex stabilizer and methylbenzimidazole-propanesulfonic acid inner salt, and continue stirring for 10-15 minutes to ensure that all components are evenly mixed, thus completing the preparation of the stripping solution.

[0034] 3. Steps for implementing the stripping and hanging method Equipment preparation: Inspect the high vacuum winding magnetron sputtering equipment, electroplating line and 500L stripping tank device (including circulation mechanism and filtration mechanism) to ensure that all equipment is operating normally; Target and substrate preparation: Select copper with a purity of ≥99.9% as the target material. Grind and clean the target surface to remove the oxide layer and impurities to ensure a smooth surface. Select an electroplating fixture with a 25μm copper deposition layer on the surface and clean it to remove dust and oil. Magnetron sputtering and electroplating: Start the high-vacuum winding magnetron sputtering equipment to deposit a 60nm thick copper layer on the functional current collector transition layer; then feed the magnetron film into the electroplating line to deposit a 1μm thick surface metal copper layer. Copper layer stripping: The pretreated electroplating fixture is placed into the stripping solution in the stripping tank, and the circulation and filtration mechanisms are started to carry out the stripping treatment at room temperature. Post-processing: After the stripping is completed, remove the electroplating fixture, clean it with pure water, and let it dry for later use; continuously monitor the status of the stripping solution, and regularly replace the filter element through the filtration mechanism to remove impurities.

[0035] Experimental Results: In this embodiment, the copper layer peeling rate was 22 μm / min, the bath temperature remained stable at 25-28℃ during the peeling process, and there were no abnormal turnovers (0 turnovers). After peeling, there was no copper layer residue or scratches on the surface of the electroplating fixture, and the substrate showed no over-corrosion. After continuous use of the peeling solution for 136 days (approximately 4.5 months), it still maintained a stable peeling effect, and under accelerated testing at 40℃, the stability period reached 4.5 months. The hydrogen peroxide decomposition rate was 3.2% after 72 hours. The peeling waste liquid contained no nitric acid or ammonia nitrogen, and copper ions could be effectively recovered through chemical precipitation, making wastewater treatment convenient.

[0036] Example 2: This embodiment is an application of the modified stripping agent formulation. The only difference from Example 1 is that the content of the stripping agent components is adjusted to 8% hydrogen peroxide and 10% sulfuric acid. The content of the molybdenum-tin heteropoly acid complex stabilizer, methylbenzimidazole-propanesulfonic acid inner salt, and other experimental conditions and implementation steps are the same as in Example 1.

[0037] Experimental results: The copper layer peeling rate was 15 μm / min, meeting the requirements of industrial production; the bath temperature remained stable at 25-27℃ during the peeling process, with no abnormal tank turnover (0 turnovers); after continuous use of the peeling solution for 112 days (approximately 3.7 months), it still maintained a stable peeling effect, and under accelerated testing at 40℃, the stability period reached 3.7 months; the hydrogen peroxide decomposition rate was 4.1% after 72 hours; after peeling, there were no residues or scratches on the fixture surface, and the substrate protection effect was good; this fine-tuned formula is suitable for scenarios with lower peeling rate requirements and a pursuit of longer peeling solution service life.

[0038] Example 3: This embodiment is an application of a finely adjusted formulation of the stripping agent components. The only difference from Example 1 is that the content of the stripping agent components is adjusted to 10% hydrogen peroxide and 15% sulfuric acid. The content of the molybdenum-tin heteropoly acid complex stabilizer, methylbenzimidazole-propanesulfonic acid inner salt, and other experimental conditions and implementation steps are the same as in Example 1.

[0039] Experimental results: The copper layer peeling rate was 18 μm / min, which is within the stable range of 15-22 μm / min, meeting the requirements of industrial production efficiency; the bath temperature remained stable at 25-27℃ during the peeling process, with no abnormal tank turnover (0 turnovers); after continuous use of the peeling solution for 125 days (approximately 4.2 months), it still maintained a stable peeling effect, and under accelerated testing at 40℃, the stable period reached 4.2 months; the hydrogen peroxide decomposition rate was 3.8% after 72 hours; after peeling, there were no residues or scratches on the fixture surface, and the substrate protection effect was good; this fine-tuned formula can be adapted to conventional production scenarios with moderate requirements for peeling rate and solution life, further verifying the flexibility of the fine-tuning of the peeling agent formula of this invention.

[0040] Example 4: This embodiment demonstrates the application of a pH-responsive corrosion inhibitor formulation with fine-tuning. The only difference from Example 1 is that the amount of methylbenzimidazole-propanesulfonic acid inner salt added is adjusted to 1.4 g / L. All other components, contents, experimental conditions, and implementation steps are the same as in Example 1.

[0041] Experimental results: The copper layer peeling rate was 21 μm / min, close to the optimal formulation level; the bath temperature remained stable at 25-28℃ during the peeling process, with no abnormal tank turnover (0 turnovers); the peeling solution was used continuously for 132 days (approximately 4.4 months), and the stability period reached 4.4 months under accelerated testing at 40℃; the hydrogen peroxide decomposition rate was 3.5% after 72 hours; after peeling, there were no residues or scratches on the fixture surface, the substrate passivation protection effect was better, and there was no over-corrosion phenomenon; this fine-tuned formulation is suitable for precision electronic electroplating scenarios with extremely high substrate protection requirements.

[0042] Comparative Example 1: This example is a control experiment. The only difference from Example 1 is that 6 g / L sodium stannate is used instead of 6 g / L molybdenum-tin heteropolyacid complex stabilizer in the stripping agent. The other components, contents, experimental conditions, and implementation steps are the same as in Example 1.

[0043] Experimental results: The copper layer peeling rate was only 6 μm / min, far lower than that of Example 1; the peeling solution had extremely poor stability and could only be used for 6 days, after which the peeling effect decreased significantly; during the peeling process, the temperature of the bath solution rose to 65-70℃ multiple times, and there were two instances of abnormal bath turnover; the decomposition rate of hydrogen peroxide after 72 hours was 45.8%; after the peeling was completed, some fixtures showed slight over-corrosion, which could not meet the substrate protection requirements for composite copper foil scenarios.

[0044] Comparative Example 2: This example is a control experiment. The only difference from Example 1 is that 5 g / L sodium pyrophosphate is used instead of 6 g / L molybdenum-tin heteropolyacid complex stabilizer in the stripping agent. The other components, contents, experimental conditions, and implementation steps are the same as in Example 1.

[0045] Experimental results: The copper layer peeling rate was 7 μm / min, which is still at a low level; the peeling solution had an effective period of 14 days and poor stability; one tank overturning anomaly occurred during the peeling process, and the highest temperature of the tank solution reached 62℃; the decomposition rate of hydrogen peroxide after 72 hours was 38.5%; the peeling effect was uneven, with copper layer residue in some areas, and the substrate protection effect was not good.

[0046] Comparative Example 3: This example is a control experiment. The only difference between this example and Example 1 is that 1.2 g / L benzotriazole is used instead of 1.2 g / L methylbenzimidazole-propanesulfonic acid inner salt (pH-responsive corrosion inhibitor) in the stripping agent. All other components, contents, experimental conditions, and implementation steps are the same as in Example 1.

[0047] Experimental results: The copper layer peeling rate was 11 μm / min, which was lower than that in Example 1; the peeling solution had a shelf life of 22 days and insufficient stability; two abnormal tank turning occurred during the peeling process, and the tank temperature reached a maximum of 68℃; the hydrogen peroxide decomposition rate was 32.7% after 72 hours; after the peeling was completed, there were slight scratches on the surface of the fixture and local over-corrosion of the substrate, which could not be adapted to scenarios with high substrate protection requirements.

[0048] Comparative Example 4: This example is a control experiment. The only difference from Example 1 is that the molar ratio of silicotungstic acid to sodium stannate in the molybdenum-tin heteropolyacid complex stabilizer is adjusted to 1:2.0. The other components, contents, experimental conditions, and implementation steps are the same as in Example 1.

[0049] Experimental results: The copper layer peeling rate was 10 μm / min, lower than the standard range of 15 μm / min, indicating insufficient peeling efficiency; the shelf life of the peeling solution was 45 days, with significantly reduced stability, failing to meet the 3-month standard; there were no abnormal turnovers during the peeling process (0 turnovers), but the hydrogen peroxide decomposition rate was 8.3% after 72 hours; after peeling, a small amount of copper layer residue remained on the fixture surface, and the substrate showed no obvious over-corrosion; these results demonstrate that deviations in the molar ratio of silicotungstic acid to sodium stannate in the molybdenum-tin heteropolyacid complex disrupt its synergistic effect with the pH-responsive corrosion inhibitor, leading to a decrease in peeling performance.

[0050] Comparative Example 5: This example is a control experiment. The only difference between this example and Example 1 is that the stripping agent does not contain methylbenzimidazole-propanesulfonic acid inner salt (no pH-responsive corrosion inhibitor). The other components, contents, experimental conditions, and implementation steps are the same as in Example 1.

[0051] Experimental results: The copper layer peeling rate was 28 μm / min, which was too fast but unstable, resulting in localized over-corrosion; the peeling solution had a shelf life of 32 days and extremely poor stability; one tank overturning anomaly occurred during the peeling process, with the highest temperature of the solution reaching 63℃; the hydrogen peroxide decomposition rate after 72 hours was 12.7%; after peeling, there were obvious scratches on the fixture surface, and the substrate showed over-corrosion, making it unsuitable for scenarios with high substrate protection requirements; these results demonstrate that the pH-responsive corrosion inhibitor is the core component of the peeling agent of this invention and is indispensable. It can not only regulate the peeling rate and protect the substrate, but also help improve the stability of hydrogen peroxide.

[0052] Comparative Example 6: This example is a control experiment. The only difference from Example 1 is that 1.2 g / L hexamethylenetetramine, a traditional organic corrosion inhibitor, is used instead of 1.2 g / L methylbenzimidazole-propanesulfonic acid inner salt. All other components, contents, experimental conditions, and implementation steps are the same as in Example 1.

[0053] Experimental results: The copper layer peeling rate was 9 μm / min, indicating low peeling efficiency; the peeling solution had a shelf life of 28 days, indicating insufficient stability; one tank overturning anomaly occurred during the peeling process, with the highest tank temperature reaching 61℃; the hydrogen peroxide decomposition rate was 10.5% after 72 hours; after peeling, copper layer residue remained on the fixture surface, and the substrate showed slight over-corrosion; these results further demonstrate that traditional organic corrosion inhibitors cannot replace the pH-responsive corrosion inhibitor of this invention, and cannot achieve a balance between peeling rate, stability, and substrate protection.

[0054] The present invention uses the following method to determine the performance values ​​of the stripping solution in each example: Copper stripping rate: Under the same temperature of 25 degrees Celsius, fill a 500ml beaker with stripping solution and place a 25μm thick copper plate on it until it is completely etched. Record the time required. Copper stripping rate = copper plating thickness (μm) / copper stripping time (min). The higher the standard, the better.

[0055] Solution shelf life: The longest number of days that can be continuously peeled off and cleaned within one batch of open tank.

[0056] Number of tank turnovers: When the temperature of the hydrogen peroxide pyrolysis tank rises above 60 degrees Celsius, it is considered an abnormality, and the standard is ≤0 times.

[0057] The measurement results for each embodiment and comparative example are shown in the table below: Table 1 Performance determination of stripping solution

[0058] The stripping agents of the various embodiments of this invention possess excellent stability, completely solving the technical problems of short storage period and easy tank turnover in existing stripping solutions. The effective period of the solutions in each embodiment is much longer than that of all comparative examples, and the number of tank turnovers is 0. The tank temperature remains stable throughout the process, without any sudden temperature rise caused by the violent decomposition of hydrogen peroxide. In contrast, all comparative examples showed abnormal tank turnover and shorter effective periods of solution. This proves that the synergistic effect of the molybdenum-tin heteropolyacid complex stabilizer and pH-responsive corrosion inhibitor in this invention can significantly inhibit hydrogen peroxide decomposition, improve the stability of the stripping solution, and meet the requirements for long-term industrial use.

[0059] The copper stripping agent of this invention exhibits a controllable and efficient copper stripping rate, adaptable to various application scenarios, while effectively protecting the substrate. The copper stripping rates in each embodiment remain stable within a reasonable range, meeting the efficiency requirements of industrial production. Fine-tuning the formulation allows for adaptation to different scenarios, verifying the flexibility of the formulation. In the comparative examples, the copper stripping rates were either too low or too fast and unstable, with most exhibiting copper layer residue, substrate scratches, or over-corrosion. However, none of the embodiments exhibited these problems, demonstrating that the formulation of this invention achieves a balance between stripping rate and substrate protection, making it suitable for scenarios with high substrate protection requirements.

[0060] In particular, replacing the molybdenum-tin heteropolyacid complex stabilizer and the pH-responsive corrosion inhibitor with other substances, not adding the pH-responsive corrosion inhibitor, or deviating from the specified ratio of the molybdenum-tin heteropolyacid complex will all lead to a significant decrease in peeling performance.

[0061] This invention's stripping agent combines practicality and environmental friendliness, facilitating large-scale industrial application. All components are conventional chemical raw materials, the preparation process is simple, and the formula can be fine-tuned according to requirements. The stripping method is simple and can be directly adapted to existing production lines without large-scale equipment modifications. The stripping waste liquid contains no harmful components, copper ions can be easily recovered, and wastewater treatment is simple and cost-effective. Compared to traditional stripping solutions, it possesses significant technical advantages and application value.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent substitutions, and improvements made by those skilled in the art to the above embodiments without departing from the scope of the technical solution of the present invention, based on the technical essence of the present invention, shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A highly stable sulfuric acid-hydrogen peroxide copper plating stripping agent, characterized in that: The stripping agent is composed of hydrogen peroxide, sulfuric acid, molybdenum-tin heteropoly acid complex stabilizer, pH-responsive corrosion inhibitor and pure water; The contents of each component are as follows: hydrogen peroxide 8~12%, sulfuric acid 10~20%, molybdenum-tin heteropolyacid complex stabilizer 5.5~6.5g / L, pH-responsive corrosion inhibitor 1~1.4g / L, and the remainder is pure water.

2. The highly stable sulfuric acid-hydrogen peroxide copper plating stripping agent according to claim 1, characterized in that: The molybdenum-tin heteropolyacid complex stabilizer is a compound of silicotungstic acid and sodium stannate in a molar ratio of 1:1.1~1.

3.

3. The highly stable sulfuric acid-hydrogen peroxide copper plating stripping agent according to claim 1, characterized in that: The pH-responsive corrosion inhibitor is activated to accelerate peeling when pH < 1 and automatically passivates to form protection when pH > 3.

4. The highly stable sulfuric acid-hydrogen peroxide copper plating stripping agent according to claim 3, characterized in that: The pH-responsive corrosion inhibitor is methylbenzimidazole-propanesulfonic acid inner salt.

5. The highly stable sulfuric acid-hydrogen peroxide copper plating stripping agent according to claim 1, characterized in that: No temperature control is required during the peeling and hanging process.

6. The highly stable sulfuric acid-hydrogen peroxide copper plating stripping agent according to claim 1, characterized in that: Using this stripping agent, the copper layer stripping rate is stable at 15~25 μm / min at room temperature.

7. The highly stable sulfuric acid-hydrogen peroxide copper plating stripping agent according to claim 1, characterized in that: The solution stability of the stripping agent is more than 3 months, and the decomposition rate of hydrogen peroxide is less than 5% after 72 hours.

8. The highly stable sulfuric acid-hydrogen peroxide copper plating stripping agent according to claim 1, characterized in that: The aforementioned stripping agent is used in conjunction with a stripping tank equipped with circulation and filtration functions.

9. A method for processing a functional current collector, characterized in that: The highly stable sulfuric acid-hydrogen peroxide copper plating stripping agent according to any one of claims 1 to 8 is used to perform stripping treatment on the functional current collector after copper plating.

10. The method for processing a functional current collector according to claim 9, characterized in that: The functional current collector contains a polymer base film layer and copper layers on both sides, wherein the copper layers include an inner magnetron sputtered copper layer and an outer electroplated copper layer.

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