Composite anti-oxidation coating and preparation method thereof

Abstract

The invention belongs to the technical field of copper foil processing, and particularly relates to a composite anti-oxidation coating and a preparation method thereof.The composite anti-oxidation coating is prepared from a first component and a second component; the first component is prepared from the following components in percentage by mass: 0.5 percent to 1 percent of L-methionine, 0.2 percent to 0.26 percent of 3-amino-1, 2-propylene glycol, 0.05 percent to 0.12 percent of inositol hexaphosphate and the balance of solvent ultrapure water; the second component comprises the following components in percentage by mass: 4%-8% of a silane coupling agent and 0.02%-0.04% of an azole compound; the rest component is an alcohol solvent; the mass ratio of the first component to the second component is (3-5): (4-4.5). Through the synergistic effect of multiple components, a composite protective layer with high density, strong adhesive force and low resistance is constructed on the surface of the copper foil, so that an excellent anti-oxidation effect is achieved, the salt mist resistance and the corrosion resistance are also remarkably improved, and the industrial production requirements of high-end electronic copper foils can be met.

Description

Technical Field

[0001] This invention relates to a composite antioxidant coating and its preparation method, belonging to the field of copper foil processing technology. Background Technology

[0002] Electronic copper foil typically requires anti-oxidation treatment during production to improve its oxidation resistance and long-term stability. Currently, the industry commonly uses surface chromium plating, which involves treating the foil in a chromium plating bath with an electroplating solution containing only chromium ions, followed by rinsing with large amounts of pure water to achieve the anti-oxidation effect. However, this process has significant limitations. On the one hand, the repeated rinsing after chromium plating consumes a large amount of pure water, increasing production costs; on the other hand, the resulting large amount of chromium-containing wastewater is difficult and costly to treat, placing a serious burden on the environment. In recent years, chromium-free environmentally friendly anti-oxidation technology has become a research hotspot. Although chromium-free environmentally friendly anti-oxidation technology avoids chromium pollution, the oxide film it forms does not perform well in terms of oxidation resistance and salt spray resistance, making it difficult to meet the requirements of industrial production, thus preventing the technology from being practically applied to date.

[0003] Therefore, there is an urgent need to develop a new type of composite antioxidant coating that can ensure the antioxidant properties of copper foil while guaranteeing the green and environmentally friendly process. Summary of the Invention

[0004] This invention addresses the problems of poor environmental performance, high water consumption, and insufficient performance of chromium-free technologies in existing technologies by providing a composite antioxidant coating and its preparation method.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: One objective of this invention is to provide a composite antioxidant coating, the raw materials of which include a first component and a second component; The first component comprises, by mass fraction: 0.5%–1% L-methionine, 0.2%–0.26% 3-amino-1,2-propanediol, 0.05%–0.12% inositol hexaphosphate, and the remainder is ultrapure water as solvent; The second component, by mass fraction, comprises: 4%–8% silane coupling agent, 0.01%–0.04% azole compound; the remainder is an alcohol solvent. The mass ratio of the first component solute to the second component solute is 3-5:4-4.5.

[0006] The beneficial effects of this invention are: The antioxidant coating of this invention uses independently formulated first and second components to ensure that the substances in each component are fully dissolved and stably exist. During use, by precisely controlling the mass ratio of the first to the second component to 3-5:4-4.5, the active substances in each component exert a synergistic effect, thereby forming a dense and uniform passivation film on the copper foil surface. This effectively blocks the penetration of oxygen and moisture, thus significantly improving the antioxidant performance of the copper foil.

[0007] Compared to traditional chromium-containing anti-oxidation processes, this invention uses an organic, chromium-free formula, completely avoiding chromium pollution and offering greater environmental friendliness and safety. Specifically: In the first component of this invention, L-methionine acts as a complexing stabilizer to form a stable complex with copper ions; 3-amino-1,2-propanediol acts as a penetrant and emulsifier to promote the uniform dissolution of inositol hexaphosphate; while inositol hexaphosphate can optimize the passivation membrane structure, making it denser and thinner, while reducing membrane resistance and improving conductivity.

[0008] In the second component of this invention, the silane coupling agent hydrolyzes to generate Si-OH bonds, which then undergo dehydration condensation to form a Si-O-Si network structure. This network structure bonds with Cu-OH on the copper foil surface to form Si-O-Cu, constituting a three-dimensional cross-linked protective layer. Furthermore, through the chemical adsorption of azole compounds with copper, Cu-nitrogen complexes perpendicular to the copper foil are formed, acting like "nails" to fix the silane network and anchor it, preventing Si-O-Si desorption. This enhances the adhesion and corrosion resistance of the passivation film, collectively constructing a denser and more effective protective passivation film layer, further improving corrosion resistance while preventing oxidation.

[0009] In summary, this invention constructs a composite protective layer on the surface of copper foil with high density, strong adhesion and low resistance through the synergistic effect of multiple components. This not only achieves excellent anti-oxidation effect, but also significantly improves salt spray resistance and corrosion resistance, which can meet the industrial production needs of high-end electronic copper foil.

[0010] Based on the above technical solution, the present invention can also be improved as follows: Furthermore, the silane coupling agent is selected from any one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, or vinyltriethoxysilane.

[0011] Furthermore, the azole compound is selected from any one of benzimidazole, benzotriazole and their derivatives.

[0012] Furthermore, the alcohol solvent is selected from ethylene glycol or glycerol.

[0013] A second objective of this invention is to provide a method for preparing the above-mentioned composite antioxidant coating, comprising the following steps: First component and second component are prepared separately. Second component is slowly added to first component and mixed evenly to obtain composite antioxidant coating liquid. Metal is completely immersed in composite antioxidant coating liquid and passivated. After passivation treatment, composite antioxidant coating is formed on metal surface.

[0014] Furthermore, the preparation of the first component specifically includes the following steps: Step 1: Add L-methionine to ultrapure water, stir to dissolve, and obtain an L-methionine solution; Step 2: Add 3-amino-1,2-propanediol to ultrapure water, stir to dissolve, and heat to 55℃~65℃ to obtain a 3-amino-1,2-propanediol solution. Step 3: Slowly add 3-amino-1,2-propanediol to the L-methionine solution and stir to mix, thus obtaining a mixture. Step 4: Add inositol hexaphosphate to the above mixture, stir and mix, make up to volume, stir at a constant temperature of 55℃~65℃ for 1h~3h, cool, and the first component is obtained.

[0015] Furthermore, the preparation of the second component specifically includes the following steps: Step 1: Slowly dissolve the silane coupling agent in a portion of an alcohol solvent, stirring to dissolve, to obtain a silane coupling agent solution; Step 2: Add the nitrazole compound to another portion of the alcohol solvent, and after dissolving, obtain a nitrazole compound solution; Step 3: Mix the silane coupling agent solution and the nitrile compound solution evenly, add alcohol solvent to the required amount, and stir for 1 to 2 hours to obtain the second component.

[0016] Furthermore, the passivation treatment is performed in an ultrasonic machine with an ultrasonic power of 30W to 50W, a frequency of 40kHz to 50kHz, and a temperature of 20℃ to 30℃.

[0017] Furthermore, after passivation, an ethanol solution is sprayed onto the metal surface, and then dried at a temperature of 30℃~35℃.

[0018] Furthermore, the metal is copper foil.

[0019] The beneficial effects of this invention are as follows: the composite antioxidant coating and its preparation method are significantly environmentally friendly and economical, avoiding the repeated water washing process after chromium plating, significantly reducing the consumption of pure water, and thus reducing production costs. The preparation method of this invention is simple, easy to operate, and readily applicable to industrial production. Detailed Implementation

[0020] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0021] Example 1 The specific steps for preparing the first component are as follows: Step 1: Add 80 mL of 80 g / L L-methionine to 300 mL of ultrapure water and stir thoroughly to dissolve, thus obtaining an L-methionine solution; Step 2: Add 65 mL of 40 g / L 3-amino-1,2-propanediol to 500 mL of ultrapure water, stir thoroughly to dissolve, heat to 60℃, and store at a constant temperature to obtain a 3-amino-1,2-propanediol solution. Step 3: Slowly add the 3-amino-1,2-propanediol solution to the L-methionine solution and stir thoroughly. Then add 25 mL of 25 g / L inositol hexaphosphate (phytic acid), stir thoroughly, add ultrapure water, and bring the volume to 1 L. Finally, heat to 60±2℃ and stir for 2 hours. After cooling to room temperature, the first component antioxidant coating liquid is obtained.

[0022] The specific steps for preparing the second component are as follows: Step 1: Slowly dissolve 10 mL of 3-aminopropyltrimethoxysilane in 50 mL of ethylene glycol, stirring thoroughly to obtain a silane coupling agent solution; Step 2: Add 20 mL of 3 g / L benzotriazole to 100 mL of ethylene glycol, stir to dissolve, and obtain BTA solution; Step 3: Mix the silane coupling agent solution and benzotriazole solution evenly, add ethylene glycol to make up to 200 mL, stir at room temperature for 1 h to obtain the second component antioxidant coating liquid.

[0023] Then, the second component of the antioxidant coating solution is slowly added to the first component of the antioxidant coating solution and mixed evenly to obtain a composite antioxidant solution, wherein the mass ratio of the first component solute to the second component solute is 3.85:4.13. The specific calculation process is as follows: Calculate the amount of each raw material used: First component solute: The mass of L-methionine is 0.08L × 80g / L = 6.4g; The mass of 3-amino-1,2-propanediol is 0.065 L × 40 g / L = 2.6 g; Inositol hexaphosphate 0.025L × 25g / L = 0.625g.

[0024] In summary, the total mass of the solute in the first component is 6.4 + 2.6 + 0.625 = 9.625 g.

[0025] Second component solute: 3-Aminopropyltrimethoxysilane (density 1.027 g / cm³) has a mass of 10 mL × 1.027 g / cm³ = 10.27 g; The mass of benzotriazole is 0.02L × 3g / L = 0.06g.

[0026] In summary, the total mass of the solute in the second component is 10.27 + 0.06 = 10.33 g.

[0027] The mass ratio of the solute in the first component to the second component is 9.625 / 10.33, which is approximately 3.85:4.13.

[0028] Untreated commercial copper foil was placed in a 75% (v / v) ethanol solution and cleaned of impurities on its surface in an ultrasonic cleaner. The cleaned copper foil was then squeezed dry by a squeeze roller. The cleaning power was 60W, the cleaning frequency was 40kHz, the cleaning temperature was 25℃, and the cleaning time was 2min.

[0029] The copper foil was then completely immersed in a composite antioxidant solution and passivated in an ultrasonic machine for 3 minutes. The ultrasonic power was 40W, the frequency was 40kHz, and the temperature was 25℃. A 75% ethanol solution was then sprayed onto the copper foil surface, and the foil was dried using a fan at an outlet temperature of 30℃.

[0030] After drying the copper foil in this embodiment, it was placed in an oven at 200°C and baked for 30 minutes. The copper foil did not oxidize or change color, which proves that the composite anti-oxidation coating of this embodiment has excellent anti-oxidation performance.

[0031] Based on Example 1, Examples 2-5 were set up. In Examples 2-5, except for the different concentrations of each raw material component, the amounts of substances not specified for addition in the first and second components were the same as in Example 1 (i.e., L-methionine, 3-amino-1,2-propanediol, inositol hexaphosphate; and azole compounds, with the same volume added as in Example 1) (see Table 1). In Example 2, the silane coupling agent was selected from 3-aminopropyltriethoxysilane, and the alcohol was selected from glycerol; in Example 3, the silane coupling agent was selected from vinyltrimethoxysilane, and the azole was selected from benzimidazole; in Example 4, the silane coupling agent was selected from vinyltriethoxysilane, and the azole was selected from 4-carboxylic acid benzotriazole; in Example 5, the azole was selected from benzimidazole. The silane coupling agent and the azole can be freely combined without restriction.

[0032] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the first component does not include L-methionine.

[0033] The copper foil in this comparative example was dried and baked in an oven at 200℃ for 30 minutes. After being removed, the copper foil showed signs of oxidation and discoloration, indicating poor anti-oxidation performance.

[0034] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the first component does not include 3-amino-1,2-propanediol.

[0035] After drying the copper foil in this comparative example and baking it in a 200℃ oven for 30 minutes, the copper foil underwent oxidation and discoloration, indicating poor anti-oxidation performance.

[0036] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the first component does not include inositol hexaphosphate.

[0037] After drying, the copper foil in this comparative example was placed in an oven at 200℃ and baked for 30 minutes. The copper foil was then removed and showed slight oxidation and discoloration, indicating poor anti-oxidation performance.

[0038] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the first component does not contain L-methionine, and the second component does not contain a silane coupling agent.

[0039] The copper foil in this comparative example was dried and baked in an oven at 200℃ for 30 minutes. After being removed, the copper foil showed signs of oxidation and discoloration, indicating poor anti-oxidation performance.

[0040] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that the first component does not contain inositol hexaphosphate, and the second component does not contain azole.

[0041] The copper foil in this comparative example was dried and baked in an oven at 200℃ for 30 minutes. After being removed, the copper foil showed signs of oxidation and discoloration, indicating poor anti-oxidation performance.

[0042] The copper foils prepared in each embodiment and comparative example were subjected to salt spray testing. The specific testing process is as follows: After placing each copper foil for 24 hours, conduct a 96-hour NSS neutral salt spray corrosion resistance test according to the standard GB / T 10125-2021. If no oxidation or discoloration occurs after 96 hours of testing, it indicates that the electroplated copper foil has better corrosion resistance.

[0043] The concentrations and performance parameters of the substances used to prepare the antioxidant coatings in each embodiment and comparative example are shown in Table 1 below: Table 1. Concentration of raw materials and performance test results of antioxidant coatings in each embodiment and comparative example.

[0044] Note: In Table 1, “√” indicates no oxidation or discoloration, and “×” indicates oxidation or discoloration.

[0045] As can be seen from the performance results in the table above, after the dried copper foils of Examples 1-5 of the present invention were baked in an oven at 200℃ for 30 minutes, no oxidation or discoloration occurred on the copper foils, indicating that the composite anti-oxidation coating prepared by the present invention has excellent anti-oxidation performance. In the salt spray test, no obvious corrosion occurred on the surface of the copper foils of Examples 1-5 of the present invention, indicating that the composite anti-oxidation coating prepared by the present invention also has excellent corrosion resistance. However, after the dried copper foils of Comparative Examples 1-5 were baked in an oven at 200℃ for 30 minutes, the copper foils all showed different degrees of oxidation coloration, indicating that the various substances in the anti-oxidation coating of the present invention work synergistically to achieve the best anti-oxidation effect, and each substance and its dosage are indispensable.

[0046] 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.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A composite antioxidant coating, characterized in that, The raw materials include a first component and a second component; The first component comprises, by mass fraction: 0.5%–1% L-methionine, 0.2%–0.26% 3-amino-1,2-propanediol, 0.05%–0.12% inositol hexaphosphate, and the remainder is ultrapure water as solvent; The second component, by mass fraction, comprises: 4%–8% silane coupling agent, 0.01%–0.04% azole compound; the remainder is an alcohol solvent. The mass ratio of the first component solute to the second component solute is 3-5:4-4.

5.

2. The composite antioxidant coating according to claim 1, characterized in that, The silane coupling agent is selected from any one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, or vinyltriethoxysilane.

3. The composite antioxidant coating according to claim 1, characterized in that, The nitrazole compounds are selected from any one of benzimidazole, benzotriazole and their derivatives.

4. The composite antioxidant coating according to claim 1, characterized in that, The alcohol solvent is selected from ethylene glycol or glycerol.

5. A method for preparing a composite antioxidant coating as described in any one of claims 1-4, characterized in that, Includes the following steps: First component and second component are prepared separately. Second component is slowly added to first component and mixed evenly to obtain composite antioxidant coating liquid. Metal is completely immersed in composite antioxidant coating liquid and passivated. After passivation treatment, composite antioxidant coating is formed on metal surface.

6. The method for preparing the composite antioxidant coating according to claim 5, characterized in that, The preparation of the first component specifically includes the following steps: Step 1: Add L-methionine to ultrapure water, stir to dissolve, and obtain an L-methionine solution; Step 2: Add 3-amino-1,2-propanediol to ultrapure water, stir to dissolve, and heat to 55℃~65℃ to obtain a 3-amino-1,2-propanediol solution. Step 3: Slowly add 3-amino-1,2-propanediol to the L-methionine solution and stir to mix, thus obtaining a mixture. Step 4: Add inositol hexaphosphate to the above mixture, stir and mix, make up to volume, stir at a constant temperature of 55℃~65℃ for 1h~3h, cool, and the first component is obtained.

7. The method for preparing the composite antioxidant coating according to claim 5, characterized in that, The preparation of the second component specifically includes the following steps: Step 1: Slowly dissolve the silane coupling agent in a portion of an alcohol solvent, stirring to dissolve, to obtain a silane coupling agent solution; Step 2: Add the nitrazole compound to another portion of the alcohol solvent, and after dissolving, obtain a nitrazole compound solution; Step 3: Mix the silane coupling agent solution and the nitrile compound solution evenly, add alcohol solvent to the required amount, and stir for 1 to 2 hours to obtain the second component.

8. The method for preparing the composite antioxidant coating according to claim 5, characterized in that, The passivation treatment is performed in an ultrasonic machine with an ultrasonic power of 30W to 50W, a frequency of 40kHz to 50kHz, and a temperature of 20℃ to 30℃.

9. The method for preparing the composite antioxidant coating according to claim 8, characterized in that, After passivation, an ethanol solution is sprayed onto the metal surface and then dried at a temperature of 30℃~35℃.

10. The method for preparing the composite antioxidant coating according to claim 5, characterized in that, The metal is copper foil.

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