Preparation method of composite copper foil and composite copper foil

Abstract

The present application provides a preparation method of a composite copper foil and the composite copper foil, the preparation method comprising: providing a substrate; modifying the surface of the substrate using a coupling agent; chemically plating the modified substrate to form a metal seed layer on the surface of the substrate; and electroplating the substrate with the metal seed layer to form a copper plating layer. Specifically, the surface of the substrate is modified using a coupling agent to improve the interface bonding force between the substrate surface and the subsequently formed copper plating layer, thereby improving the mechanical properties of the composite copper foil.

Description

Technical Field

[0001] The present application relates to the technical field of conductive films, and in particular to a preparation method of a composite copper foil and the composite copper foil. Background Art

[0002] Composite copper foil is widely used in the current collector of battery negative electrode materials, which includes an intermediate substrate layer and a conductive metal layer located on both sides of the intermediate substrate layer, similar to a sandwich structure. This composite current collector not only has excellent ductility, but also reduces the amount of metal copper and reduces the weight of the battery, thereby increasing the energy density of the battery and greatly improving the safety performance.

[0003] Among them, the existing technology for preparing composite copper foil mostly adopts magnetron sputtering to form a metal seed layer on the substrate layer, and then electroplating to form a copper plating layer. However, the bonding force between the copper plating layer formed by this method and the substrate layer is poor, resulting in poor mechanical properties of the composite copper foil. Summary of the invention

[0004] In order to solve the above problems, the present application provides a method for preparing a composite copper foil and a composite copper foil, which can solve the problem of poor bonding strength between a base material layer and a copper plating layer in existing composite copper foils.

[0005] In order to solve the above problems, the first technical solution provided in the present application is: to provide a method for preparing a composite copper foil, comprising:

[0006] providing a substrate;

[0007] Using a coupling agent to modify the surface of the substrate;

[0008] Performing chemical plating on the surface-modified substrate to form a metal seed layer on the surface of the substrate;

[0009] The substrate having the metal seed layer formed thereon is electroplated to form a copper plating layer.

[0010] In one embodiment, the surface modification of the substrate using a coupling agent comprises:

[0011] The substrate is treated with hydrolyzed aminosilane; wherein the surface of the treated substrate has aminosilane groups.

[0012] In one embodiment, the surface modification of the substrate using a coupling agent further comprises:

[0013] The treated substrate is subjected to ultraviolet irradiation.

[0014] In one embodiment, the step of subjecting the treated substrate to ultraviolet radiation comprises:

[0015] The treated substrate is irradiated with ultraviolet light at a power of 280-350W.

[0016] In one embodiment, before the surface treatment of the substrate with a coupling agent, the method further comprises:

[0017] Spraying the substrate with an acetone solution to form a plurality of grooves on the surface of the substrate;

[0018] The substrate after spraying is soaked in an ethanol solution to remove the residual acetone solution on the surface of the substrate.

[0019] In one embodiment, the step of performing chemical plating on the treated substrate to form a metal seed layer on the surface of the substrate comprises:

[0020] The substrate is immersed in a first mixed solution containing copper sulfate, ethylenediaminetetraacetic acid and polyethylene glycol;

[0021] Then, the soaked substrate is sprayed with an aqueous solution containing formaldehyde to form a metal seed layer on the surface of the substrate.

[0022] In one embodiment, before soaking the treated substrate with the first mixed solution containing copper sulfate, ethylenediaminetetraacetic acid and polyethylene glycol, the method further comprises:

[0023] The substrate treated with the coupling agent is immersed in a sensitizing liquid, wherein the sensitizing liquid includes tin element;

[0024] The substrate treated with the sensitizing liquid is sprayed with an activation liquid, wherein the activation liquid includes a lead element;

[0025] Then wash with water to remove the excess activation solution;

[0026] After forming the metal seed layer on the surface of the substrate, the method further comprises:

[0027] The substrate on which the metal seed layer is formed is washed with water; wherein the substrate is subjected to ultrasonic treatment during the washing process;

[0028] The washed substrate is dried.

[0029] In one embodiment, the step of forming a copper plating layer on the substrate having the metal seed layer formed thereon by electroplating comprises:

[0030] acid washing the substrate on which the metal seed layer is formed;

[0031] Then, a second mixed solution containing copper ions, chloride ions, sulfuric acid and polyethylene glycol is used to perform a first electroplating on the substrate having the metal seed layer formed thereon;

[0032] Washing the substrate after the first electroplating;

[0033] Then, a third mixed solution containing copper ions, chloride ions, sulfuric acid, polyethylene glycol and sodium polypropylene sulfonate is used to perform a second electroplating on the substrate after the first electroplating;

[0034] Washing the substrate after the second electroplating;

[0035] Then, the washed substrate is subjected to surface anti-oxidation treatment.

[0036] In order to solve the above problems, the second technical solution provided in the present application is: to provide a composite copper foil, wherein the composite copper foil is prepared by any of the preparation methods described above.

[0037] In order to solve the above problems, the third technical solution provided by the present application is: to provide a composite copper foil, the composite copper foil comprising:

[0038] Base material;

[0039] A metal seed layer is disposed on two opposite surfaces of the substrate, and the substrate is connected to the metal seed layer via an aminosilane group;

[0040] The copper plating layer is located on the surface of the metal seed layer facing away from the substrate.

[0041] The beneficial effect of the present application is that, different from the prior art, the preparation method of the composite copper foil provided by the present application uses a coupling agent to modify the surface of the substrate to improve the interface bonding force between the substrate surface and the subsequently formed copper plating layer, thereby improving the mechanical properties of the composite copper foil. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0043] Figure 1 A schematic diagram of a process for preparing a composite copper foil provided in one embodiment of the present application;

[0044] Figure 2 A schematic diagram of a process for preparing a composite copper foil provided in another embodiment of the present application;

[0045] Figure 3 for Figure 1 A schematic flow chart of an embodiment of step S3;

[0046] Figure 4 for Figure 1 A schematic diagram of a flow chart of an embodiment of step S4;

[0047] Figure 5 A schematic diagram of a portion of the intermediate product of the composite copper foil after step S1;

[0048] Figure 6 A schematic diagram of a portion of an intermediate product of a composite copper foil after step S01;

[0049] Figure 7 A schematic diagram of a portion of the intermediate product of the composite copper foil after step S2;

[0050] Figure 8 A schematic diagram of a portion of the intermediate product of the composite copper foil after step S3;

[0051] Fig. 9 is a schematic diagram of a portion of the structure of the composite copper foil after step S4;

[0052] Fig.10 A schematic diagram of a partial structure of a composite copper foil provided in one embodiment of the present application.

[0053] Description of labels:

[0054] Substrate-10; aminosilane group-20; metal seed layer-30; copper plating layer-40. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0056] The terms "first", "second", "third", etc. in this application are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first", "second", "third" may explicitly or implicitly include at least one of the features.

[0057] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0058] The above are only implementation methods of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

[0059] See also Figure 1 , Figure 1 A schematic diagram of a process for preparing a composite copper foil provided in one embodiment of the present application.

[0060] The present application embodiment provides a method for preparing a composite copper foil, comprising:

[0061] Step S1: providing a substrate 10.

[0062] See Figure 5 , Figure 5 Schematic diagram of some intermediate products of composite copper foil after step S1. Optionally, the substrate 10 can be formed of materials such as PE (polyethyene), PC (Polycarbonate), PTFE (polytetrafluoroethylene), PET (polyethylene glycol terephthalate) or PP film. Among them, PE, PC, PET and PP have good flexibility, which can ensure that the composite copper foil has good bending properties so that it can be wound and easy to transport; PTFE has good acid and alkali resistance, and chemical plating requires the substrate 10 to be acid and alkali resistant, and resistant to chemical corrosion.

[0063] Step S2: using a coupling agent to modify the surface of the substrate 10.

[0064] In the present application, the substrate 10 has two opposite surfaces. Specifically, the coupling agent can improve the interface bonding force between the surface of the substrate 10 and the subsequent film layer, thereby improving the mechanical properties, electrical properties and environmental resistance of the composite material.

[0065] In the present application, the coupling agent is a silane coupling agent, and the silane coupling agent includes but is not limited to aminosilane, epoxysilane, and methacryloxysilane.

[0066] Of course, in other embodiments, titanate coupling agents, aluminate coupling agents, phosphate coupling agents, etc. may also be used, which is not limited here.

[0067] In the embodiment of the present application, step S2 includes: treating the substrate 10 with hydrolyzed aminosilane.

[0068] See Figure 7 , Figure 7 Schematic diagram of a portion of the intermediate product of the composite copper foil after step S2. Specifically, the surface of the substrate 10 treated with the hydrolyzed aminosilane has an aminosilane group 20. The side of the aminosilane containing silicon and oxygen will be connected to the substrate 10, while the amino side can be used as an active point for subsequent chemical plating to form a metal seed layer 30.

[0069] In one scenario, hydrolyzed aminosilane is used to spray the surface of the substrate 10, and in this scenario, the linear speed of the substrate 10 is 1.2-2.4 m / min. For example, the linear speed of the substrate 10 can be 1.2 m / min, 1.6 m / min, 2 m / min, or 2.4 m / min, etc., which is not limited here.

[0070] In one embodiment, step S2 further includes: subjecting the treated substrate 10 to ultraviolet radiation.

[0071] Specifically, after the substrate 10 is treated with the hydrolyzed aminosilane, the substrate 10 is subjected to ultraviolet irradiation cross-linking, in order to provide reaction conditions for increasing the connection between the aminosilane and the substrate 10 .

[0072] In one embodiment, the ultraviolet irradiation on the treated substrate 10 includes: ultraviolet irradiation on the treated substrate 10 with a power of 280-350W.

[0073] For example, the treated substrate 10 may be irradiated with ultraviolet light at a power of 280 W, 300 W, 320 W or 350 W.

[0074] See also Figure 2 , Figure 2 A schematic diagram of a process for preparing a composite copper foil provided in another embodiment of the present application. In the embodiment of the present application, before step S2, the process further includes:

[0075] Step S01 : spraying the substrate 10 with an acetone solution to form a plurality of grooves 101 on the surface of the substrate 10 .

[0076] Step S02 : soaking the sprayed substrate 10 with an ethanol solution to remove the residual acetone solution on the surface of the substrate 10 .

[0077] See Figure 6 , Figure 6 Schematic diagram of a portion of the intermediate product of the composite copper foil after step S01. Specifically, compared with laser drilling, the substrate 10 is sprayed with an acetone solution to form a plurality of grooves 101 on the surface of the substrate 10. The groove depths of the plurality of grooves 101 are more uniform, which can improve the consistency of the groove depths.

[0078] The plurality of grooves 101 may be evenly distributed on two opposite surfaces of the substrate 10 .

[0079] In one scenario, the substrate 10 passes through two micro-etching tanks, two water washing tanks, and finally is dried. Specifically, the first micro-etching tank uses acetone as a solvent and adopts a spraying method. The main function of acetone is to dissolve the substrate 10 to form a number of grooves 101 on the surface of the substrate 10; the second micro-etching tank uses ethanol as a solvent and adopts an immersion method to clean the acetone remaining on the surface of the substrate 10; the first water washing tank adopts an immersion water washing method, and the second water washing tank adopts a spraying method to clean the organic residue on the surface of the substrate 10; finally, the surface of the substrate 10 is dried.

[0080] In this scenario, the linear speed of the substrate 10 is about 4-7 m / min. For example, the linear speed of the substrate 10 can be 4 m / min, 5 m / min, 7 m / min, etc., which is not limited here.

[0081] Step S3 : performing chemical plating on the surface-modified substrate 10 to form a metal seed layer 30 on the surface of the substrate 10 .

[0082] See Figure 8 , Figure 8 Schematic diagram of some intermediate products of the composite copper foil after step S3. In the embodiment of the present application, the metal seed layer 30 is a copper seed layer. Specifically, by forming the metal seed layer 30 on the surface of the substrate 10, the metal seed layer 30 serves as the basis for the subsequent electroplated copper layer, providing the necessary conductivity, so that the subsequent electroplating process can be carried out uniformly on the entire film surface. In addition, the metal seed layer 30 can also improve the interface bonding force between the substrate 10 and the final copper plating layer 40, ensuring that the composite copper foil is structurally stable and not easy to delaminate during subsequent processing and use.

[0083] See also Figure 3 , Figure 3 for Figure 1 Schematic diagram of a flow chart of an embodiment of step S3 in the embodiment of the present application. In the embodiment of the present application, step S3 includes:

[0084] Step S31: soaking the substrate 10 treated with the coupling agent in a sensitizing liquid; wherein the sensitizing liquid includes tin element.

[0085] In one scenario, the substrate 10 treated with the coupling agent is moved to a sensitization tank, which uses 5.4-6.3 g / l tin sulfate and 32.5-46.8 g / l sulfuric acid as sensitization liquids, and the tank is immersed, the main purpose of which is to absorb part of Sn. 2 + On the surface of the substrate 10 or in the cavity (groove 101) after etching the substrate 10.

[0086] Step S32: spraying the substrate 10 treated with the sensitizing solution with an activation solution; wherein the activation solution includes lead element.

[0087] In one scenario, the substrate 10 treated with the sensitizing solution is moved to an activation tank, which uses lead sulfate with a concentration of 0.44-1.1 g / l and sulfuric acid with a concentration of 8.8-9.5 g / l as the activation solution, and the tank adopts a spray type, the main purpose of which is to allow Pb 2+ The reduction of tin ions provides activation sites on the surface of the substrate 10 for subsequent copper plating.

[0088] Step S33: then wash with water to remove excess activation solution.

[0089] In one scenario, the substrate 10 treated with the activation solution is moved to a water washing tank, and the tank is a spray type, the main purpose of which is to wash away the activation solution remaining on the surface of the substrate 10 .

[0090] Step S34: soaking the substrate 10 with a first mixed solution containing copper sulfate, ethylenediaminetetraacetic acid and polyethylene glycol.

[0091] In one scenario, the washed substrate 10 is moved to a chemical plating tank, which uses a copper sulfate solution with a concentration of 6.2-8.0 g / l, ethylenediaminetetraacetic acid with a concentration of 25-34 g / l, polyethylene glycol with a concentration of 150-250 ppm, and 150-250 ppm as the first mixed solution. Its main function is to fix copper ions in an activated position through chelation to prepare for the next reduction reaction. The chemical plating tank adopts an immersion type.

[0092] Step S35 : spraying the soaked substrate 10 with an aqueous solution containing formaldehyde to form a metal seed layer 30 on the surface of the substrate 10 .

[0093] In one scenario, the chemically plated substrate 10 is moved to a reduction tank, which uses a formaldehyde aqueous solution with a concentration of 5.42-10.83 g / l and sodium hydroxide is used to adjust the pH to 11.2-13.4. The tank adopts a spray type with a liquid temperature of 60-70°C. Its main function is to adsorb copper ions on the surface of the substrate 10 through the reduction of formaldehyde to form a metal seed layer 30.

[0094] Step S36: washing the substrate 10 with the metal seed layer 30 formed thereon with water; wherein, during the washing process, the substrate 10 is subjected to ultrasonic treatment.

[0095] In one scenario, the substrate 10 formed with the metal seed layer 30 is moved to a water washing tank. The water washing tank is of immersion type and equipped with ultrasonic waves. The main function of the water washing tank is to clean and remove the unreacted copper solution and reducing solution on the surface of the substrate 10 .

[0096] Step S37: Drying the washed substrate 10.

[0097] In one scenario, the surface of the substrate 10 is dried at 80-150 degrees Celsius. In this scenario, the linear speed of the substrate 10 is about 0.3-0.6 m / min. For example, the linear speed of the substrate 10 can be 0.3 m / min, 0.5 m / min, 0.6 m / min, etc., which is not limited here.

[0098] It can be understood that in the preparation method provided by the present application, in the process of forming the metal seed layer 30 on the surface of the substrate 10, there is no need to use magnetron sputtering equipment, thereby avoiding the high cost of using magnetron sputtering equipment to generate composite copper foil equipment, the need for a vacuum environment, and many difficulties in production process control.

[0099] Step S4: forming a copper plating layer 40 on the substrate 10 with the metal seed layer 30 formed thereon by electroplating.

[0100] See Fig. 9 , Fig. 9 Schematic diagram of a part of the structure of the composite copper foil after step S4, wherein the substrate 10 formed with the metal seed layer 30 is electroplated to increase the thickness of the copper layer to form a copper plating layer 40, thereby forming a composite copper foil.

[0101] Specifically, the preparation method of the composite copper foil provided in the present application uses a coupling agent to modify the surface of the substrate 10 to improve the interface bonding strength between the surface of the substrate 10 and the subsequently formed metal seed layer 30, and finally improves the interface bonding strength between the substrate 10 and the copper plating layer 40, thereby improving the mechanical properties of the composite copper foil.

[0102] See also Figure 4 , Figure 4 for Figure 1 FIG. 1 is a flow chart of an embodiment of step S4 in FIG. 1 . In the embodiment of the present application, step S4 includes:

[0103] Step S41 : acid-washing the substrate 10 on which the metal seed layer 30 is formed.

[0104] In one scenario, the substrate 10 formed with the metal seed layer 30 is moved to an acid pickling tank. The acid pickling tank uses sulfuric acid with a concentration of 90-120 g / l. Its main purpose is to clean and remove copper oxide on the surface of the substrate 10.

[0105] Step S42: Then, a second mixed solution containing copper ions, chloride ions, sulfuric acid and polyethylene glycol is used to perform a first electroplating on the substrate 10 formed with the metal seed layer 30 .

[0106] In one scenario, the pickled substrate 10 is moved to a first electroplating tank, which uses a copper ion concentration of 85-95 g / l, sulfuric acid of 102-115 g / l, chloride ions of 20-30 ppm and polyethylene glycol of 150-230 ppm as the second mixed solution, which mainly acts on the surface of the substrate 10 formed with the metal seed layer 30, and forms a copper plating layer 40 through electroplating thickening.

[0107] Among them, in this scenario, the current density is 9-15A / dm 2 For example, the current density can be 9A / dm 2 、11A / dm 2 、13A / dm 2 or 15A / dm 2 , no limitation is made here.

[0108] Step S43: washing the substrate 10 after the first electroplating.

[0109] In one scenario, the substrate 10 after the first electroplating is moved to a water washing tank. The water washing tank is a spray type, and its main function is to clean and remove the second mixed solution remaining on the surface of the substrate 10.

[0110] Step S44: Then, a third mixed solution containing copper ions, chloride ions, sulfuric acid, polyethylene glycol and sodium polypropylene sulfonate is used to perform a second electroplating on the substrate 10 after the first electroplating.

[0111] In one scenario, the washed substrate 10 is moved to a second electroplating tank, which uses a third mixed solution of 85-95 g / l copper ions, 95-105 g / l sulfuric acid, 25-30 ppm chloride ions, 150-200 ppm polyethylene glycol and 0.65-0.75 g / l sodium polypropylene sulfonate, which is mainly used to further finely electroplate the surface of the copper plating layer 40 to form a dense copper plating layer 40.

[0112] Among them, in this scenario, the current density is 5-9A / dm 2 For example, the current density can be 5A / dm 2 、6A / dm 2, 8A / dm 2 or 9A / dm 2 , no limitation is made here.

[0113] Step S45: washing the substrate 10 after the second electroplating.

[0114] In one scenario, the substrate 10 after the second electroplating is moved to a water washing tank, which is a spray type. Its main function is to clean and remove the third mixed solution remaining on the surface of the composite copper foil.

[0115] Step S46: Then, the washed substrate 10 is subjected to surface anti-oxidation treatment.

[0116] In one scenario, the surface of the composite copper foil is chrome-plated at a speed of 4-8 m / min. For example, the speed may be 4 m / min, 6 m / min, 8 m / min, etc., which is not limited here.

[0117] The following are specific examples and comparative examples of the method for preparing the composite copper foil provided in this application.

[0118] Example 1

[0119] In Example 1, the substrate is a PET substrate, and the surface and grooves of the substrate are surface modified by hydrolyzed aminosilane. The surface-modified substrate is chemically plated with a first mixed solution to form a metal seed layer, and the substrate with the metal seed layer is electroplated to form a copper plating layer.

[0120] Example 2

[0121] In Example 2, the substrate is a PET substrate, and the surface and grooves of the substrate are surface-modified by using hydrolyzed aminosilane, and the surface-modified substrate is irradiated with ultraviolet light. Then, the surface-modified substrate is chemically plated with a first mixed solution to form a metal seed layer, and the substrate with the metal seed layer is electroplated to form a copper plating layer.

[0122] Example 3

[0123] In Example 3, the substrate is a PET substrate, and the surface and grooves of the substrate are surface-modified using hydrolyzed aminosilane, and the surface-modified substrate is treated with a sensitizing solution and an activation solution. The surface-modified substrate is then chemically plated with a first mixed solution to form a metal seed layer, and a copper plating layer is formed on the substrate with the metal seed layer by electroplating.

[0124] Example 4

[0125] In Example 4, the substrate is a PET substrate, and the surface and grooves of the substrate are surface-modified using hydrolyzed aminosilane, and the surface-modified substrate is irradiated with ultraviolet light, and then the substrate after ultraviolet irradiation is treated with a sensitizing solution and an activation solution, and then the surface-modified substrate is chemically plated with a first mixed solution to form a metal seed layer, and the substrate with the metal seed layer is electroplated to form a copper plating layer.

[0126] Comparative Example 1

[0127] In Comparative Example 1, the substrate is a PET substrate, and a metal seed layer is formed by magnetron sputtering. Then, a copper plating layer is formed on the substrate having the metal seed layer by electroplating.

[0128] The results of the interfacial bonding strength between the substrate and the copper plating layer in the composite copper foil formed in the above Examples 1-4 and Comparative Example 1 are shown in the following Table 1.

[0129] Table 1

[0130] serial number Interface bonding strength between substrate and copper plating Example 1 5-7N / cm Example 2 5-8N / cm Example 3 5-8N / cm Example 4 6-9N / cm Comparative Example 1 3-4N / cm

[0131] It can be seen from Table 1 that in the metal copper foil formed by forming a metal seed layer by magnetron sputtering and then electroplating, the interface bonding force between the substrate and the copper plating layer is the worst.

[0132] And it can be seen from Table 1 that compared with Example 1, that is, after the surface of the substrate is modified by aminosilane, the surface-modified substrate is directly chemically plated with the first mixed solution to form a metal seed layer, Example 2 uses aminosilane to modify the surface of the substrate and then uses ultraviolet irradiation, which can improve the interface bonding strength between the substrate and the copper plating layer.

[0133] And it can be seen from Table 1 that compared with Example 1, that is, after the surface of the substrate is modified by aminosilane, the surface-modified substrate is directly chemically plated with the first mixed solution to form a metal seed layer, Example 3 also treats the surface-modified substrate with a sensitizing solution and an activating solution before chemically plating the surface-modified substrate with the first mixed solution to form a metal seed layer, which can enhance the interfacial bonding strength between the substrate and the copper plating layer.

[0134] And it can be seen from Table 1 that compared with Comparative Example 1, Example 1, Example 2, and Example 3, the surface of the substrate and the grooves are surface modified by hydrolyzed aminosilane, and the surface-modified substrate is subjected to ultraviolet irradiation, and then the ultraviolet-irradiated substrate is treated with a sensitizing solution and an activation solution, and then the surface-modified substrate is chemically plated with a first mixed solution to form a metal seed layer, and the substrate with the metal seed layer is electroplated to form a copper coating. In the final composite copper foil, the interface bonding force between the substrate and the copper coating is the largest, reaching 6-9N / cm, which effectively improves the mechanical properties of the composite copper foil.

[0135] See also Fig.10 , Fig.10 A schematic diagram of a partial structure of a composite copper foil provided in one embodiment of the present application.

[0136] Specifically, the present application also provides a composite copper foil, including a substrate 10 , a metal seed layer 30 and a copper plating layer 40 .

[0137] The material of the substrate 10 may be PE (polyethyene), PC (Polycarbonate), PTFE (polytetrafluoroethylene), PET (polyethylene glycolterephthalate) or PP film, etc.

[0138] Specifically, PE, PC, PET and PP have good flexibility, which can ensure that the composite copper foil has good bendability, so that it can be rolled up for easy transportation; while PTFE has good acid and alkali resistance, and chemical plating requires the substrate 10 to be acid and alkali resistant, and resistant to chemical corrosion. Therefore, the material of the substrate 10 can be selected according to actual needs.

[0139] The metal seed layer 30 is located on two opposite surfaces of the substrate 10, and the copper plating layer 40 is located on the surface of the seed layer away from the substrate 10. In the embodiment of the present application, the metal seed layer 30 is a copper seed layer, and the substrate 10 is connected to the metal seed layer 30 through the aminosilane group 20.

[0140] Specifically, by forming a metal seed layer 30 on the surface of the substrate 10, the metal seed layer 30 serves as the basis for the subsequent electroplated copper layer and provides the necessary conductivity, so that the subsequent electroplating process can be carried out evenly on the entire film surface. In addition, the metal seed layer 30 can also improve the interface bonding force between the substrate 10 and the final copper plating layer 40, ensuring that the composite copper foil is structurally stable and not easy to delaminate during subsequent processing and use.

[0141] In the embodiment of the present application, the substrate 10 is connected to the metal seed layer 30 through the aminosilane group 20. The side of the aminosilane group 20 containing silicon and oxygen will be connected to the substrate 10, and the amino side can be connected to the metal seed layer 30 as an active point, thereby improving the interface bonding force between the substrate 10 and the metal seed layer 30 and the final copper plating layer 40, and improving the mechanical properties of the composite copper foil.

[0142] In one embodiment, the composite copper foil can be prepared by the preparation method provided in any of the above embodiments. Specifically, the composite copper foil prepared by the above preparation method in the present application can not only save equipment costs, but also can be produced by only primary low-cost production equipment, and can improve the interface bonding force between the surface of the substrate 10 and the subsequently formed metal seed layer 30 and the finally formed copper plating layer 40, thereby improving the mechanical properties of the composite copper foil.

[0143] The above are only implementation methods of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for preparing a composite copper foil, characterized in that: include: Providing a substrate; Using a coupling agent to modify the surface of the substrate; Performing chemical plating on the surface-modified substrate to form a metal seed layer on the surface of the substrate; The substrate having the metal seed layer formed thereon is electroplated to form a copper plating layer.

2. The preparation method according to claim 1, characterized in that: The method of using a coupling agent to modify the surface of the substrate comprises: The substrate is treated with hydrolyzed aminosilane; wherein the surface of the treated substrate has aminosilane groups.

3. The preparation method according to claim 2, characterized in that: The method of using a coupling agent to modify the surface of the substrate further comprises: The treated substrate is subjected to ultraviolet irradiation.

4. The preparation method according to claim 3, characterized in that: The step of subjecting the treated substrate to ultraviolet irradiation comprises: The treated substrate is irradiated with ultraviolet light at a power of 280-350W.

5. The preparation method according to any one of claims 1 to 4, characterized in that: Before the substrate is surface treated with a coupling agent, the method further comprises: Spraying the substrate with an acetone solution to form a plurality of grooves on the surface of the substrate; The substrate after spraying is soaked in an ethanol solution to remove the residual acetone solution on the surface of the substrate.

6. The preparation method according to any one of claims 1 to 4, characterized in that: The step of chemically plating the treated substrate to form a metal seed layer on the surface of the substrate comprises: The substrate is immersed in a first mixed solution containing copper sulfate, ethylenediaminetetraacetic acid and polyethylene glycol; Then, the soaked substrate is sprayed with an aqueous solution containing formaldehyde to form a metal seed layer on the surface of the substrate.

7. The preparation method according to claim 6, characterized in that: Before soaking the treated substrate with the first mixed solution containing copper sulfate, ethylenediaminetetraacetic acid and polyethylene glycol, the method further comprises: The substrate treated with the coupling agent is immersed in a sensitizing liquid, wherein the sensitizing liquid includes tin element; The substrate treated with the sensitizing liquid is sprayed with an activation liquid, wherein the activation liquid includes a lead element; Then wash with water to remove the excess activation solution; After forming the metal seed layer on the surface of the substrate, the method further comprises: The substrate on which the metal seed layer is formed is washed with water; wherein the substrate is subjected to ultrasonic treatment during the washing process; The washed substrate is dried.

8. The preparation method according to any one of claims 1 to 4, characterized in that: The step of forming a copper plating layer on the substrate having the metal seed layer formed thereon by electroplating comprises: acid washing the substrate on which the metal seed layer is formed; Then, a second mixed solution containing copper ions, chloride ions, sulfuric acid and polyethylene glycol is used to perform a first electroplating on the substrate having the metal seed layer formed thereon; Washing the substrate after the first electroplating; Then, a third mixed solution containing copper ions, chloride ions, sulfuric acid, polyethylene glycol and sodium polypropylene sulfonate is used to perform a second electroplating on the substrate after the first electroplating; Washing the substrate after the second electroplating; Then, the washed substrate is subjected to surface anti-oxidation treatment.

9. A composite copper foil, characterized in that: The composite copper foil is prepared by the preparation method described in any one of claims 1 to 8.

10. A composite copper foil, characterized in that: The composite copper foil comprises: Base material; A metal seed layer is disposed on two opposite surfaces of the substrate, and the substrate is connected to the metal seed layer via an aminosilane group; The copper plating layer is located on the surface of the metal seed layer facing away from the substrate.

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