Electrolytic copper foil and method for producing the same

Abstract

The application discloses electrolytic copper foil and a preparation method thereof, and the preparation method comprises the following steps: providing an electrolyte and an electrolytic green foil and post-processing, preparing a copper sulfate solution, and adding an additive into the obtained copper sulfate solution to obtain an electrolyte; the additive comprises A agent, B agent and E agent; the A agent comprises 8-16 g / L of polypeptide protein in terms of mass concentration, the B agent comprises 5-10 g / L of polydithiodipropyl sulfone sodium and 1-3 g / L of 3-mercapto-1-propane sulfonic acid sodium, and the E agent comprises 1-5 g / L of gelatin. In the preparation method, the additive for the electrolytic copper foil is added in the preparation process of the electrolytic copper foil, so that the prepared electrolytic copper foil can dynamically respond to changes in temperature and other conditions in the environment, the mechanical properties remain stable under different temperature conditions, and the reliability of electronic equipment is improved.

Description

Technical Field

[0001] This invention relates to the field of copper foil processing technology, and in particular to an electrolytic copper foil and its preparation method. Background Technology

[0002] Electrolytic copper foil, a key material in the fields of electronics, information technology, and new energy, plays a crucial role in high-power-density chips, electric vehicle battery management systems, and high-frequency communication equipment, performing essential functions such as conductivity, heat conduction, and signal transmission. During operation, these components generate significant heat, causing drastic temperature fluctuations (from -40°C to 150°C or even higher) on both the components themselves and the supporting circuit board (PCB). Because the mechanical properties of existing electrolytic copper foil, including tensile strength and elongation, are unsuitable for such harsh environments, the reliability and lifespan of electronic devices are affected, limiting the development of high-end electronic equipment.

[0003] Therefore, it is essential to provide an electrolytic copper foil and its preparation method that can dynamically respond to changes in environmental conditions such as temperature, maintain stable mechanical properties under different temperature conditions, and improve the reliability of electronic devices. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned problems and provide an electrolytic copper foil and its preparation method. By adding the additives for electrolytic copper foil described in this invention to the preparation process of the electrolytic copper foil, the prepared electrolytic copper foil can dynamically respond to changes in environmental conditions such as temperature, maintain stable mechanical properties under different temperature conditions, and improve the reliability of electronic devices.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a method for preparing electrolytic copper foil, comprising the steps of: Provide electrolyte: Prepare copper sulfate solution, add additives to the obtained copper sulfate solution to obtain electrolyte; the additives include agent A, agent B and agent E; by mass concentration, agent A includes 8-16 g / L of polypeptide protein, agent B includes 5-10 g / L of sodium polydisulfide dipropanesulfonate and 1-3 g / L of sodium 3-mercapto-1-propanesulfonate, and agent E includes 1-5 g / L of gelatin; Electrolytic foil production and post-processing: The obtained electrolyte is fed into the foil production equipment for electrolytic foil production to generate basic copper foil; the post-processing includes passivation treatment and baking treatment of the obtained basic copper foil.

[0006] Optionally, when adding additives to the obtained copper sulfate solution, the usage amounts of each component of the additives are as follows: the usage amount of agent A is 40-100 mL / min, the usage amount of agent B is 50-100 mL / min, and the usage amount of agent E is 100-200 mL / min.

[0007] Optionally, the mass concentration of copper sulfate in the copper sulfate solution is 55-140 g / L.

[0008] Optionally, the current density during the electrolysis of the foil is 500-6000 A / m. 2 The temperature of the copper sulfate solution is 45-75℃, and the time is 1-5 minutes.

[0009] Optionally, after the passivation treatment, a passivation film layer with a thickness of 50-150 nm is formed on the surface of the base copper foil.

[0010] Optionally, the baking temperature is 75-90℃, and the baking time is greater than 5 hours.

[0011] Optionally, the preparation of copper sulfate solution includes the following steps: mixing raw copper with sulfuric acid to dissolve and generate a first solution; coarsely filtering the obtained first solution to obtain a first filtrate; purifying the obtained first filtrate to obtain a purified solution; finely filtering the obtained purified solution to obtain the copper sulfate solution; and then adjusting the temperature of the obtained copper sulfate solution using a plate heat exchanger.

[0012] Optionally, in the purification process, the amount of activated carbon added is 100-200g / 2h.

[0013] Optionally, the preparation method further includes electrolyte reflux, wherein the electrolyte reflux includes the step of: refluxing the lean electrolyte generated during the electrolytic foil production process to participate in the preparation of copper sulfate solution.

[0014] Secondly, the present invention provides an electrolytic copper foil, which is prepared by the preparation method described above.

[0015] The beneficial effects of this invention include at least the following: This invention regulates the microstructure and interfacial properties of electrolytic copper foil by synergistically adding Agent A, Agent B, and Agent E to the electrolyte. This endows the copper foil with dynamic response to changes in ambient temperature, ensuring stable mechanical properties under different temperature conditions and thus improving the reliability of electronic devices. Agent A includes polypeptides as a flexible polymer component that can bind to the copper foil grain boundaries to form an elastic buffer layer. During temperature changes, the stretching and deformation of the molecular chains effectively alleviates the internal stress caused by thermal expansion and contraction of the copper foil, preventing performance degradation such as grain boundary cracking and embrittlement. Agent B, composed of SPS and MPS, precisely refines the copper foil grains, reduces grain boundary defects, and improves the thermal stability of the copper foil's microcrystalline structure, ensuring that its crystalline structure is not easily distorted under temperature fluctuations and guaranteeing the stability of core mechanical properties such as tensile strength and ductility. Agent E, with its synergistic effect of gelatin and polypeptides, further optimizes the grain boundary bonding force of the copper foil, enhances the flexibility of the copper foil substrate, and improves its adaptability to temperature changes. The synergistic combination of components enables the copper foil to dynamically respond to changes in ambient temperature from multiple dimensions, including microstructure regulation, thermal stress mitigation, and substrate toughness optimization. This ensures that the mechanical properties of the prepared electrolytic copper foil remain stable under different temperature conditions, effectively preventing electronic equipment failures caused by copper foil temperature changes, and significantly improving the operational stability and service life of electronic equipment in complex temperature-changing environments. Attached Figure Description

[0016] Figure 1 This is a process flow diagram for preparing the electrolytic copper foil of the present invention. Detailed Implementation

[0017] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0018] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0019] In a first aspect, the present invention provides a method for preparing electrolytic copper foil, see [link to previous section]. Figure 1 As shown, it includes the following steps: Provide electrolyte: Prepare copper sulfate solution, add additives to the obtained copper sulfate solution to obtain electrolyte; the additives include agent A, agent B and agent E; by mass concentration, agent A includes 8-16 mg / L of polypeptide protein, agent B includes 5-10 mg / L of sodium polydisulfide dipropane sulfonate (SPS) and 1-3 mg / L of sodium 3-mercapto-1-propane sulfonate (MPS), and agent E includes 1-5 mg / L of gelatin; Electrolytic foil production and post-processing: The obtained electrolyte is fed into the foil production equipment for electrolytic foil production to generate basic copper foil; the post-processing includes passivation treatment and baking treatment of the obtained basic copper foil.

[0020] This invention regulates the microstructure and interfacial properties of electrolytic copper foil by synergistically adding Agent A, Agent B, and Agent E to the electrolyte. This endows the copper foil with dynamic response to changes in ambient temperature, ensuring stable mechanical properties under different temperature conditions and thus improving the reliability of electronic devices. Agent A includes polypeptides as a flexible polymer component that can bind to the copper foil grain boundaries to form an elastic buffer layer. During temperature changes, the stretching and deformation of the molecular chains effectively alleviates the internal stress caused by thermal expansion and contraction of the copper foil, preventing performance degradation such as grain boundary cracking and embrittlement. Agent B, composed of SPS and MPS, precisely refines the copper foil grains, reduces grain boundary defects, and improves the thermal stability of the copper foil's microcrystalline structure, ensuring that its crystalline structure is not easily distorted under temperature fluctuations and guaranteeing the stability of core mechanical properties such as tensile strength and ductility. Agent E, with its synergistic effect of gelatin and polypeptides, further optimizes the grain boundary bonding force of the copper foil, enhances the flexibility of the copper foil substrate, and improves its adaptability to temperature changes. The synergistic combination of components enables the copper foil to dynamically respond to changes in ambient temperature from multiple dimensions, including microstructure regulation, thermal stress mitigation, and substrate toughness optimization. This ensures that the mechanical properties of the prepared electrolytic copper foil remain stable under different temperature conditions, effectively preventing electronic equipment failures caused by copper foil temperature changes, and significantly improving the operational stability and service life of electronic equipment in complex temperature-changing environments.

[0021] Optionally, when adding additives to the obtained copper sulfate solution, the usage amounts of each component of the additives are as follows: the usage amount of agent A is 40-100 mL / min, the usage amount of agent B is 50-100 mL / min, and the usage amount of agent E is 100-200 mL / min.

[0022] Optionally, the mass concentration of copper sulfate in the copper sulfate solution is 55-140 g / L.

[0023] Optionally, the current density during the electrolysis of the foil is 500-6000 A / m. 2 The temperature of the copper sulfate solution is 45-75℃, and the time is 1-5 minutes.

[0024] Optionally, after the passivation treatment, a passivation film layer with a thickness of 50-150 nm is formed on the surface of the base copper foil.

[0025] Optionally, the baking temperature is 75-90℃, and the baking time is greater than 5 hours. The baking conditions provided by this invention allow the passivation film to cure slowly and fully, improving film adhesion and density, thoroughly removing residual moisture from the surface, avoiding appearance defects such as watermarks, while gently eliminating electrolytic internal stress, improving the flexibility of the copper foil, adapting to the temperature-sensitive characteristics of ultra-thin copper foil, and preventing thermal deformation. This low-temperature, long-time process avoids the problems of passivation film cracking, copper foil oxidation, and grain coarsening and embrittlement caused by high-temperature baking, ensuring the corrosion resistance, conductivity, and dimensional stability of the copper foil, and meeting the requirements of subsequent processing and storage.

[0026] Optionally, the preparation of the copper sulfate solution includes the following steps: mixing raw copper with sulfuric acid to dissolve and generate a first solution; coarsely filtering the obtained first solution to remove large particulate solid impurities, obtaining a first filtrate; purifying the obtained first filtrate to adsorb and remove organic impurities, heavy metal ions (iron / lead / zinc, etc.), and oil residues, obtaining a purified solution; finely filtering the obtained purified solution to remove activated carbon powder and trace impurities, obtaining the filtrate as the copper sulfate solution; and then adjusting the temperature of the obtained copper sulfate solution using a plate heat exchanger to adjust the temperature of the copper sulfate solution to the process threshold for the subsequent electrolytic foil production.

[0027] Optionally, in the purification process, the amount of activated carbon added is 100-200 g / 2 h. This amount of activated carbon is designed to avoid both insufficient addition leading to purification failure and excessive addition causing secondary contamination of the electrolyte or loss of components.

[0028] Optionally, in some other embodiments, the preparation method further includes electrolyte reflux, which includes the step of refluxing the electrolyte-poor solution generated during the electrolytic foil production process to participate in the preparation of copper sulfate solution. Specifically, the electrolyte-poor solution formed in the electrolytic foil production step is refluxed and mixed with the first filtrate obtained after the coarse filtration step. The electrolyte reflux operation forms a closed-loop circulation of the electrolyte and a dynamic balance of the electrolyte. During the electrolytic foil production process, a reduction reaction occurs on the surface of the cathode roller of the foil production equipment, and copper ions in the electrolyte continuously deposit into copper foil, resulting in a decrease in the concentration of copper ions in the electrolyte and the formation of electrolyte-poor solution, while the concentration of sulfuric acid increases relatively. Refluxing the electrolyte-poor solution and re-participating it in the step of preparing copper sulfate electrolyte replenishes the first solution with copper ions and dilutes excess sulfuric acid, thus recycling the electrolyte, reducing production costs, ensuring the stability of the composition of the copper sulfate electrolyte, and ensuring uniform thickness and consistent performance of the copper foil product.

[0029] Secondly, the present invention provides an electrolytic copper foil, which is prepared by the preparation method described above.

[0030] The preparation process of the electrolytic copper foil samples in Examples 1 to 10 all include the preparation of copper sulfate solution, electrolysis of raw foil, and post-treatment; the only difference is the amount of each component added in the additives.

[0031] Example 1: The additive composition of this example includes: 8-16 g / L of polypeptide protein, 5-10 g / L of SPS, 1-3 g / L of MPS and 1-5 g / L of gelatin; the usage of agent A is 50 mL / min, the usage of agent B is 70 mL / min and the usage of agent E is 120 mL / min.

[0032] Example 2: The additive composition of this example includes: 8-16 g / L of polypeptide protein, 5-10 g / L of SPS, 1-3 g / L of MPS and 1-5 g / L of gelatin; the usage of agent A is 100 mL / min, the usage of agent B is 150 mL / min and the usage of agent E is 200 mL / min.

[0033] Example 3: The additive composition of this example includes: 8-16 g / L of polypeptide protein, 5-10 g / L of SPS, 1-3 g / L of MPS and 1-5 g / L of gelatin; the usage of agent A is 75 mL / min, the usage of agent B is 110 mL / min and the usage of agent E is 160 mL / min.

[0034] Example 4: The additive composition of this example includes: 8-16 g / L of polypeptide protein, 5-10 g / L of SPS, 1-3 g / L of MPS and 1-5 g / L of gelatin; the usage of agent A is 60 mL / min, the usage of agent B is 90 mL / min and the usage of agent E is 140 mL / min.

[0035] Example 5: The additive composition of this example includes: 8-16 g / L of polypeptide protein, 5-10 g / L of SPS, 1-3 g / L of MPS and 1-5 g / L of gelatin; the usage of agent A is 80 mL / min, the usage of agent B is 130 mL / min and the usage of agent E is 180 mL / min.

[0036] Example 6: The additive composition of this example includes: 8-16 g / L of polypeptide protein, 5-10 g / L of SPS, 1-3 g / L of MPS and 1-5 g / L of gelatin; the usage of agent A is 55 mL / min, the usage of agent B is 140 mL / min and the usage of agent E is 190 mL / min.

[0037] Example 7: The additive composition of this example includes: 8-16 g / L of polypeptide protein, 5-10 g / L of SPS, 1-3 g / L of MPS and 1-5 g / L of gelatin; the usage of agent A is 95 mL / min, the usage of agent B is 80 mL / min and the usage of agent E is 130 mL / min.

[0038] Example 8: The additive composition of this example includes: 8-16 g / L of polypeptide protein, 5-10 g / L of SPS, 1-3 g / L of MPS and 1-5 g / L of gelatin; the usage of agent A is 65 mL / min, the usage of agent B is 120 mL / min and the usage of agent E is 170 mL / min.

[0039] Example 9: The additive composition of this example includes: 8-16 g / L of polypeptide protein, 5-10 g / L of SPS, 1-3 g / L of MPS and 1-5 g / L of gelatin; the usage of agent A is 85 mL / min, the usage of agent B is 100 mL / min and the usage of agent E is 150 mL / min.

[0040] Example 10: The additive composition of this example includes: 8-16 g / L of polypeptide protein, 5-10 g / L of SPS, 1-3 g / L of MPS and 1-5 g / L of gelatin; the usage of agent A is 70 mL / min, the usage of agent B is 115 mL / min and the usage of agent E is 165 mL / min.

[0041] Electrolytic copper foils prepared in Examples 1 to 10 were used to create test samples of the same specifications, with dimensions of length × width = 12.7 mm × 12.7 mm; corresponding to sample numbers 1 to 10. Tensile strength and elongation were tested on samples numbered 1 to 10 under ambient temperature, medium temperature (130℃), and high temperature (150℃) conditions. The tensile strength test included longitudinal and transverse tensile strength tests, and the elongation test also included longitudinal and transverse elongation tests.

[0042] Table 1. Test table of tensile strength and elongation of test samples numbered 1 to 10 under normal temperature conditions.

[0043] Table 2. Test table of tensile strength and elongation of test samples numbered 1 to 10 under medium temperature conditions.

[0044] Table 3. Test table of tensile strength and elongation of test samples numbered 1 to 10 under normal temperature conditions.

[0045] Table 1 shows the tensile strength and elongation test results for samples numbered 1 to 10 at room temperature. Table 2 shows the tensile strength and elongation test results for samples numbered 1 to 10 at medium temperature; the medium temperature test conditions are: test temperature 130℃, test time 10 min. Table 3 shows the tensile strength and elongation test results for samples numbered 1 to 10 at room temperature; the medium temperature test conditions are: test temperature 150℃, test time 180 min.

[0046] Referring to Tables 1 to 3, as the test temperature increases, the tensile strength of the electrolytic copper foil decreases moderately, while the elongation increases significantly. Its core properties are as follows: Intelligent temperature-dependent mechanical properties: In the room temperature / medium temperature range, it maintains high tensile strength (e.g., >450MPa), ensuring excellent mechanical support and processability; in the high temperature range, the tensile strength decreases gradually, while the elongation increases sharply (e.g., at 150℃, the elongation can be more than 100% higher than at room temperature), exhibiting extraordinary toughness. Excellent thermal fatigue resistance: The extremely high high temperature elongation can effectively buffer and disperse thermal stress, greatly improve the life of the circuit in extreme temperature cycling test (TCT), and reduce the risk of failure such as circuit cracking and copper separation caused by thermal expansion coefficient mismatch. Stable electrical performance: Maintains low resistivity and stable signal transmission performance over a wide temperature range to meet the requirements of high-frequency and high-speed applications; Excellent compatibility: Compatible with mainstream PCB manufacturing processes (such as subtractive and semi-additive processes) without requiring changes to existing production processes.

[0047] This invention demonstrates that by synergistically adding Agent A, Agent B, and Agent E to the electrolyte, the microstructure and interfacial properties of the electrolytic copper foil are regulated, thereby endowing the copper foil with dynamic response to changes in ambient temperature, maintaining stable mechanical properties under different temperature conditions, and thus improving the reliability of electronic devices.

[0048] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0049] The above embodiments merely illustrate preferred implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A method for preparing electrolytic copper foil, characterized in that, Including the following steps: Provide electrolyte: Prepare copper sulfate solution, add additives to the obtained copper sulfate solution to obtain the electrolyte; the additives include agent A, agent B and agent E; by mass concentration, agent A includes 8-16 mg / L of polypeptide protein, agent B includes 5-10 mg / L of sodium polydisulfide dipropanesulfonate and 1-3 mg / L of sodium 3-mercapto-1-propanesulfonate, and agent E includes 1-5 mg / L of gelatin; Electrolytic foil production and post-processing: The obtained electrolyte is fed into the foil production equipment for electrolytic foil production to generate basic copper foil; the post-processing includes passivation treatment and baking treatment of the obtained basic copper foil.

2. The method for preparing electrolytic copper foil according to claim 1, characterized in that, When adding additives to the obtained copper sulfate solution, the usage amounts of each component of the additives are as follows: the usage amount of agent A is 40-100 mL / min, the usage amount of agent B is 50-100 mL / min, and the usage amount of agent E is 100-200 mL / min.

3. The method for preparing electrolytic copper foil according to claim 1, characterized in that, The copper sulfate solution contains copper sulfate with a mass concentration of 55-140 g / L.

4. As described in claim 1, characterized in that, The current density during the electrolysis of the foil is 500-6000 A / m 2 The temperature of the copper sulfate solution is 45-75℃, and the time is 1-5 minutes.

5. The method for preparing electrolytic copper foil according to claim 1, characterized in that, After the passivation treatment, a passivation film with a thickness of 50-150 nm is formed on the surface of the base copper foil.

6. The method for preparing electrolytic copper foil according to claim 1, characterized in that, The baking temperature is 75-90℃, and the baking time is greater than 5 hours.

7. The method for preparing electrolytic copper foil according to claim 1, characterized in that, The preparation of copper sulfate solution includes the following steps: mixing raw copper with sulfuric acid to dissolve and generate a first solution; The first solution is coarsely filtered to obtain the first filtrate; the first filtrate is purified to obtain the purified solution; the purified solution is finely filtered to obtain the copper sulfate solution; and the temperature of the copper sulfate solution is adjusted by a plate heat exchanger.

8. The method for preparing electrolytic copper foil according to claim 7, characterized in that, In the purification process, the amount of activated carbon added is 100-200g / 2h.

9. The method for preparing electrolytic copper foil according to claim 7, characterized in that, The preparation method further includes electrolyte reflux, wherein the electrolyte reflux includes the step of: refluxing the lean electrolyte generated during the electrolytic foil production process to participate in the preparation of copper sulfate solution.

10. An electrolytic copper foil, characterized in that, The electrolytic copper foil is prepared using the preparation method described in any one of claims 1-9.

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