Copper foil anti-oxidation surface treating agent as well as preparation method and use method thereof

Abstract

The invention belongs to the technical field of surface treatment, and particularly discloses a copper foil anti-oxidation surface treating agent and a preparation method and a use method thereof, and the copper foil anti-oxidation surface treating agent is composed of the following components by mass: 0.5-5% of a silane coupling agent; 0.1 to 5.0 percent of organic silicon resin; 0.1 to 2.0 percent of benzotriazole; 0.5-5% of ammonia water; 2-5% of ethanol; and the balance of deionized water. Before use, the anti-oxidation surface treating agent and water are mixed to obtain surface treating fluid, and then the surface treating fluid is applied to the surface of the copper foil in a spraying or soaking mode. The copper foil anti-oxidation surface treating agent disclosed by the invention is environment-friendly, safe, simple in preparation process and low in cost, and has good anti-oxidation performance and anti-stripping performance.

Description

Technical Field

[0001] The invention belongs to the technical field of surface treatment, relates to copper foil surface treatment, and specifically relates to an anti-oxidation surface treatment agent for copper foil and a preparation method and a use method thereof. Background Art

[0002] Copper foil is widely used in industrial communications, microcomputer systems, electronic products and other fields due to its excellent thermal conductivity, electrical conductivity and good processing performance. Especially in recent years, driven by the craze of 5G, big data and intelligence, new energy and electronic products are developing in the direction of high precision, small size and light weight. As the core component of printed circuit boards and negative current collectors of lithium-ion batteries, the production of copper foil is gradually becoming more refined and ultra-thin.

[0003] In the application of printed circuit boards, electrolytic copper foil that has not been passivated has poor resistance to high-temperature oxidation and low peeling strength, and is prone to copper diffusion, causing short circuits and short circuits in printed circuit boards. In the application of lithium-ion batteries, copper foil, as a negative electrode current collector, is also required to have certain anti-oxidation and anti-peeling properties to prevent battery performance degradation due to oxidation or shedding of negative electrode materials during use. Therefore, whether it is a printed circuit board or a lithium-ion battery application, it needs to undergo surface passivation treatment to meet the use requirements of electronic components.

[0004] Traditional copper foil passivation uses hexavalent chromium or trivalent chromium passivation technology, which has good effect, low cost, and can achieve self-repair. However, with the increase of people's environmental awareness and the increasingly stringent environmental regulations, chromate passivation has been banned. Therefore, the development of environmentally friendly copper foil passivation technology is a technical problem that technicians in this field are looking forward to solving. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide an antioxidant surface treatment agent for copper foil and a preparation method and a use method thereof. The antioxidant surface treatment agent for copper foil of the present invention is environmentally friendly and safe, has a simple preparation process, low cost, and has good antioxidant and anti-stripping properties.

[0006] The technical solution of the present invention is achieved in this way: A copper foil anti-oxidation surface treatment agent is composed of the following components in percentage by mass: 0.5-5% of silane coupling agent; 0.1-5.0% of organic silicon resin; 0.1-2.0% of benzotriazole; 0.5-5% of ammonia water; 2-5% of ethanol; and the rest is deionized water.

[0007] Furthermore, the silane coupling agent is one or more of 1,2-bis-(triethoxysilyl)ethane, bis-[γ-(triethoxysilyl)propyl]tetrasulfide, γ-glycidyloxypropyltrimethoxysilane or other silane coupling agents or silane coupling agent modified products.

[0008] Furthermore, the organic silicone resin is one or more of alkoxy silicone resin, amino silicone resin, carboxyl silicone resin or other organic silicone resins or modified products of organic silicone resin.

[0009] Furthermore, the mass percentage of each component is as follows: silane coupling agent 1-3%; silicone resin 2-4%; benzotriazole 0.5-1.5%; ammonia water 1-3%; ethanol 2.5-4%; and the rest is deionized water.

[0010] Furthermore, the mass percentage of each component is as follows: silane coupling agent 1.2%; silicone resin 2.5%; benzotriazole 1.1%; ammonia water 2.5%; ethanol 3%; deionized water 89.7%.

[0011] The method for preparing the above-mentioned copper foil anti-oxidation surface treatment agent specifically comprises the following steps: (1) Prepare the materials according to the components of the copper foil antioxidant surface treatment agent described above, and divide the deionized water into two parts, A and B, with the deionized water in part A accounting for 70-80% of the total mass of the deionized water; (2) Add benzotriazole into ammonia water, stir until dissolved, then add it into part A of deionized water and stir thoroughly to obtain a first solution.

[0012] (3) adding ethanol into a reaction kettle, and then slowly adding a silane coupling agent and an organosilicon resin into the reaction kettle in sequence, stirring while adding, to obtain a second solution; (4) slowly adding the second solution into the first solution and stirring for more than 4 h to obtain a third solution; (5) Pour the deionized water (part B) into the third solution while stirring, and stir evenly to obtain the copper foil antioxidant surface treatment agent.

[0013] Furthermore, before use, the copper foil antioxidant surface treatment agent and water are mixed to obtain a surface treatment liquid, which is then applied to the copper foil surface by spraying or immersion and dried; wherein the copper foil antioxidant surface treatment agent accounts for 3-5% of the surface treatment liquid, and the pH of the surface treatment liquid is 7.5-8.5.

[0014] Furthermore, during spraying, the spraying time is 0.5-1 min, the spraying pressure is 0.5-1.5 bar, and the drying temperature is 60-80°C.

[0015] Furthermore, during soaking, the soaking time is 1-3 min and the soaking temperature is 10-40°C.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The use of the copper foil antioxidant surface treatment agent of the present invention can form a film layer with a thickness of 100-1000nm on the surface of the copper foil. Ammonia increases the solubility of benzotriazole and provides a weak alkaline environment to promote the hydrolysis of silane coupling agent and silicone resin. After hydrolysis, the silane coupling agent and silicone resin form silanol groups, and some of the silanol groups combine with the hydroxyl groups on the metal surface to form Si-O-Me adsorbed on the surface of the copper foil, thereby forming a surface film on the surface of the copper foil, improving the antioxidant performance and corrosion resistance of the copper foil; some of the silanol groups are dehydrated and condensed to form oligosiloxanes containing silanol groups, further increasing the thickness of the surface film and improving the protective performance; the lone pair of electrons of the nitrogen atom in benzotriazole forms a coordination bond with the empty orbit of the metal copper, adsorbed on the copper surface to increase the thickness of the protective film; some of the silanol groups are linked to -NH- in benzotriazole, and such mutual cross-linking makes the silane coupling agent, silicone resin and benzotriazole form a whole with a certain thickness, which is adsorbed on the surface of the copper foil.

[0017] At the same time, the remaining silanol groups in the adsorption film can also combine with the subsequent matching resin rubber sheet or negative electrode binder to improve the adhesion strength between the resin rubber sheet or negative electrode binder and the copper foil surface, improve the anti-peeling performance, and prevent the resin rubber sheet or negative electrode binder from falling off.

[0018] 2. The raw materials used in the present invention are all common substances, free of phosphorus, heavy metals, and BOD / COD emissions, complying with the EU ROHS environmental protection directive and REACH standards, and the preparation process is simple, low in cost, and low in energy consumption, which is conducive to industrial promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 -Microscopic morphology of the surface treatment film layer of untreated copper foil and copper foil treated with the copper foil antioxidant treatment agent of Example 1.

[0020] Figure 2 - Macroscopic photos of the untreated copper foil and the copper foil treated with the antioxidant treatment agents of Examples 1 to 3 and Comparative Examples 1 to 3 after high temperature oxidation resistance test. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0022] Example 1 In this embodiment, the copper foil anti-oxidation surface treatment agent is composed of the following components in percentage by mass: 1.2% silane coupling agent (KH550); 2.5% organic silicone resin (alkoxy silicone resin); 1.1% benzotriazole; 2.5% ammonia water; 3% ethanol; and 89.7% deionized water.

[0023] The copper foil anti-oxidation surface treatment agent is prepared according to the following steps: (1) Prepare the materials according to the composition of the copper foil antioxidant surface treatment agent described above, and divide the deionized water into two parts, A and B, with the deionized water in part A accounting for 80% of the total mass of the deionized water; (2) Add benzotriazole into ammonia water, stir to dissolve, then add to part A of deionized water, and stir thoroughly to obtain a first solution; (3) adding ethanol into a reaction kettle, and then slowly adding a silane coupling agent and an organosilicon resin into the reaction kettle while stirring, to obtain a second solution; (4) Slowly adding the second solution into the first solution and stirring for 4 h to obtain a third solution; (5) Pour the deionized water (part B) into the third solution while stirring, and stir evenly to obtain the copper foil antioxidant surface treatment agent.

[0024] When in use, first mix the copper foil antioxidant surface treatment agent and deionized water to obtain a surface treatment liquid, in which the copper foil antioxidant surface treatment agent accounts for 3%, and then spray it onto the surface of the copper foil. The spraying time is 1 min and the spraying pressure is 1 bar. Finally, dry it at a drying temperature of 80°C to obtain a surface treatment film layer on the surface of the copper foil.

[0025] Example 2 This embodiment is the same as Embodiment 1, except that the anti-oxidation surface treatment agent for copper foil in this embodiment is composed of the following components in percentage by mass: 3.0% silane coupling agent (KH560); 2.0% organic silicone resin (alkoxy silicone resin); 1.2% benzotriazole; 1.8% ammonia water; 4% ethanol; and 88.0% deionized water.

[0026] Example 3 This embodiment is the same as Embodiment 1, except that the anti-oxidation surface treatment agent for copper foil in this embodiment is composed of the following components in percentage by mass: 1% silane coupling agent (KH560); 2% organic silicone resin (amino silicone resin); 1.4% benzotriazole; 2.3% ammonia water; 3% ethanol; and 90.3% deionized water.

[0027] Comparative Example 1 This embodiment is the same as Embodiment 1, except that the anti-oxidation surface treatment agent for copper foil in this embodiment is composed of the following components in percentage by mass: 3% silane coupling agent (KH550); 0.05% organic silicone resin (amino silicone resin); 0.9% benzotriazole; 1.6% ammonia water; 4% ethanol; and 90.45% deionized water.

[0028] Comparative Example 2 This embodiment is the same as Embodiment 1, except that the anti-oxidation surface treatment agent for copper foil in this embodiment is composed of the following components in percentage by mass: 0.3% silane coupling agent (KH560); 4% organic silicone resin (alkoxy silicone resin); 1.1% benzotriazole; 1.8% ammonia water; 3% ethanol; and 89.8% deionized water.

[0029] Comparative Example 3 This embodiment is the same as Embodiment 1, except that the anti-oxidation surface treatment agent for copper foil in this embodiment is composed of the following components in percentage by mass: 2.5% silane coupling agent (KH560); 3.5% organic silicone resin (amino silicone resin); 0.3% benzotriazole; 0.4% ammonia water; 4% ethanol; and 89.3% deionized water.

[0030] Comparative Example 4 This embodiment is the same as the embodiment 1, except that the anti-oxidation surface treatment agent for the copper foil in this embodiment does not contain silicone resin.

[0031] 1. The microscopic morphology of the surface treatment film layer of the untreated copper foil and the copper foil treated with the copper foil antioxidant treatment agent of Example 1 is as follows Figure 1 As shown, and correspond to Figure 1 (a) and Figure 1 (b) As can be seen from the figure: the surface of the untreated copper foil is evenly covered with fine precipitated copper nodules with clear edges and corners. After treatment, the surface becomes slightly smoother.

[0032] 2. The high temperature antioxidant performance of the untreated copper foil and the copper foil treated with the antioxidant treatment agent of Examples 1 to 3 and Comparative Examples 1 to 3 was tested. The test was carried out in an electric constant temperature drying oven, the temperature was set to 160°C, and the baking time was 30 minutes. The obtained macroscopic photos are as follows: Figure 2 As shown, Figure 2 (a) is untreated copper foil. Figure 2 (b) to (g) are copper foils treated with the anti-oxidation surface treatment agents of Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2 and Comparative Example 3, respectively.

[0033] It can be seen from the figure that the surface of the untreated copper foil has undergone serious oxidation discoloration. The copper foil treated by Examples 1, 2, and 3 still shows the original metallic luster, and no oxidation discoloration occurs, indicating that the surface treatment film has played a very good protective role on the copper foil substrate. The surface of the copper foil treated by Comparative Examples 1, 2, and 3 is significantly improved compared with the untreated one, but the phenomenon of oxidation discoloration still occurs, and the area of ​​oxidation discoloration accounts for approximately 50%, 30%, and 80% of the total area.

[0034] 3. The untreated copper foil and the copper foil treated with the antioxidant treatment agent of Examples 1 to 3 and Comparative Examples 1 to 4 were subjected to adhesion test. Specifically: the negative electrode slurry was coated on the above copper foil respectively, and the side coated with the negative electrode slurry was attached to the stretching piece using cyanoacrylate resin glue, with an attachment area of ​​1 cm 2 ; The other side of the copper foil is glued to the fixing part with glue, and the pasting area is larger than 5cm 2 , 80℃ curing for 20 minutes, placed at room temperature for 24 hours and then tested the tensile force when the tensile part fell off, the tensile angle was 45°, and the average value was taken after 8 tests. The test results are as follows: It can be seen from the above table that, compared with the untreated copper foil, the adhesion between the treated copper foil and the negative electrode slurry is significantly improved, and the improvement in Examples 1, 2, and 3 is more obvious.

[0035] Finally, it should be noted that the above embodiments of the present invention are only examples for illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes and modifications can be made based on the above description. It is impossible to list all implementation methods here. Any obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A copper foil anti-oxidation surface treatment agent, characterized in that: The copper foil anti-oxidation surface treatment agent is composed of the following components in percentage by mass: 0.5-5% of silane coupling agent; 0.1-5.0% of organic silicon resin; 0.1-2.0% of benzotriazole; 0.5-5% of ammonia water; 2-5% of ethanol; and the rest is deionized water.

2. The anti-oxidation surface treatment agent for copper foil according to claim 1, characterized in that: The silane coupling agent is one or more of 1,2-bis-(triethoxysilyl)ethane, bis-[γ-(triethoxysilyl)propyl]tetrasulfide, γ-glycidyloxypropyltrimethoxysilane or other silane coupling agents or silane coupling agent modified products.

3. The anti-oxidation surface treatment agent for copper foil according to claim 1, characterized in that: The organic silicone resin is one or more of alkoxy silicone resin, amino silicone resin, carboxyl silicone resin or other organic silicone resins or modified products of organic silicone resin.

4. The anti-oxidation surface treatment agent for copper foil according to claim 1, 2 or 3, characterized in that: The mass percentage of each component is as follows: 1-3% of silane coupling agent; 2-4% of silicone resin; 0.5-1.5% of benzotriazole; 1-3% of ammonia water; 2.5-4% of ethanol; and the rest is deionized water.

5. The anti-oxidation surface treatment agent for copper foil according to claim 4, characterized in that: The mass percentage of each component is: silane coupling agent 1.2%; silicone resin 2.5%; benzotriazole 1.1%; ammonia water 2.5%; ethanol 3%; deionized water 89.7%.

6. The method for preparing a copper foil anti-oxidation surface treatment agent according to any one of claims 1 to 5, characterized in that: The specific steps include: (1) preparing the components of the copper foil antioxidant surface treatment agent according to any one of claims 1 to 5, and dividing deionized water into two parts, A and B, wherein the deionized water in part A accounts for 70-80% of the total mass of the deionized water; (2) putting benzotriazole into ammonia water, stirring to dissolve, then adding it into part A of deionized water, stirring thoroughly to obtain a first solution; (3) adding ethanol into a reaction kettle, and then slowly adding a silane coupling agent and an organosilicon resin into the reaction kettle in sequence, stirring while adding, to obtain a second solution; (4) slowly adding the second solution into the first solution and stirring for more than 4 h to obtain a third solution; (5) Pour the deionized water (part B) into the third solution while stirring, and stir evenly to obtain the copper foil antioxidant surface treatment agent.

7. The method for using the anti-oxidation surface treatment agent for copper foil according to any one of claims 1 to 5, characterized in that: Before use, the copper foil antioxidant surface treatment agent and deionized water are mixed to obtain a surface treatment solution, which is then applied to the copper foil surface by spraying or immersion and dried; wherein the copper foil antioxidant surface treatment agent accounts for 3-5% of the surface treatment solution.

8. The method for using the anti-oxidation surface treatment agent for copper foil according to claim 7, characterized in that: When spraying, the spraying time is 0.5-1 min, the spraying pressure is 0.5-1.5 bar, and the drying temperature is 60-80℃.

9. The method for using the anti-oxidation surface treatment agent for copper foil according to claim 7, characterized in that: When soaking, the soaking time is 1-3 min and the soaking temperature is 10-40 ℃.

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