Composite metal foil and preparation method and application thereof

Abstract

The invention relates to the technical field of cables, in particular to a composite metal foil and a preparation method and application thereof. The composite metal foil comprises a composite base material layer and a shielding layer which are arranged in a stacked mode, and the melting temperature of the composite base material layer is 120-280 DEG C; the composite base material layer comprises a connecting layer and a base material layer which are laminated, and the shielding layer is connected with the base material layer through the connecting layer; the base material layer and the shielding layer can be tightly connected together through the material of the connecting layer, so that the composite metal foil has excellent elongation, meanwhile, during tin immersion welding, the composite base material layer is melted after reaching the melting temperature, the copper layer is exposed, a good tinning effect is achieved, and the manufacturing quality of the cable is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of cable technology, and in particular to a composite metal foil and a preparation method and application thereof. Background Art

[0002] Wires and cables include outer insulation layer, cable shielding layer, internal conductor, insulation filling, etc. The function of the cable shielding layer is to reduce the impact of external electromagnetic interference on the signal. The shielding layer can be metal foil, metal wire braiding layer or metal coating layer to form an electromagnetic barrier and improve the anti-interference ability of the cable.

[0003] Common shielding layer types include: aluminum foil shielding material, copper foil shielding material, and aluminum-copper double-layer shielding material. Aluminum foil, as a lightweight and flexible material, is often used in single-layer or multi-layer shielding structures. It can effectively block the interference of high-frequency electromagnetic waves and is widely used in communication cables and data transmission cables. Compared with aluminum foil, copper foil shielding has better conductivity and oxidation resistance, and has longer shielding effect and service life. At present, some manufacturers choose composite copper foil as the shielding layer. It has better ductility and tensile resistance when used as cable shielding, and is lighter in weight and uses less copper.

[0004] Generally speaking, the composite copper foil shielding layer is set on the cable by spiral winding. Since server cables usually require a longer length, in order to ensure that the composite copper foil does not break during the winding process, the composite copper foil must show sufficient tensile strength and ductility. In addition, the composite copper foil acts as a shielding layer, so the composite copper foil insulation layer must also meet welding requirements. During welding, it is difficult to expose the composite copper foil when doing grounding soldering after wrapping the cable. The traditional method relies on flux containing multiple halogen activators to promote welding, but this is inconsistent with the growing environmental protection trend and the halogen-free standards vigorously promoted by the electronics industry. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the existing composite copper foil cannot take into account both the shielding effect and the material quality when used for cable shielding, thereby providing a composite metal foil and its preparation method and application.

[0006] A first aspect of the present invention protects a composite metal foil, wherein the composite metal foil includes a composite substrate layer and a shielding layer stacked together, the melting temperature of the composite substrate layer is 120°C to 280°C; the composite substrate layer includes a connecting layer and a substrate layer stacked together, and the shielding layer is connected to the substrate layer through the connecting layer.

[0007] According to the present invention, the melting temperature of the composite substrate layer is 140-200°C.

[0008] In the present invention, the substrate layer material is a conventional substrate layer material in the art, typically but not limitingly, the substrate layer material includes one or more of PET, PP, PI, PVC, PE, EVA, and PC; the shielding layer is a conventional shielding layer material in the art, typically but not limitingly, the shielding layer material is a metal, specifically including one or more of copper, aluminum, gold, silver, iron, nickel, chromium, and zinc.

[0009] According to the present invention, the bonding force between the composite substrate layer and the shielding layer is greater than 0.4 N / cm.

[0010] In the present invention, a tensile peeling test is used to measure the bonding force between the substrate layer and the shielding layer.

[0011] According to the present invention, the thermal expansion coefficient of the composite substrate layer is 40 ppm / °C to 140 ppm / °C.

[0012] According to the present invention, the connecting layer material is a polymer material, including one or more of polyurethane, water-soluble epoxy resin, acrylic acid, polyamide, and phenolic resin, preferably a combination of water-soluble epoxy resin and polyurethane.

[0013] In the present invention, the weight average molecular weight of polyurethane is 3000-10000 g / mol; the weight average molecular weight of water-soluble epoxy resin is 2000-8000 g / mol; the weight average molecular weight of acrylic acid is 2000-8000 g / mol; the weight average molecular weight of polyamide is 2000-8000 g / mol; and the weight average molecular weight of phenolic resin is 3000-7000 g / mol.

[0014] According to the present invention, the thickness D1 of the substrate layer and the thickness D2 of the connecting layer satisfy the following relationship: 5 μm ≤ D1 + D2 ≤ 8 μm.

[0015] According to the present invention, the thickness D1 of the substrate layer and the thickness D2 of the connecting layer satisfy the following relationship: 2 μm ≤ D1 / D2 ≤ 7 μm.

[0016] According to the present invention, the thickness D2 of the connection layer is 1 μm-5 μm.

[0017] According to the present invention, the thickness D1 of the substrate layer is 4 μm-6 μm.

[0018] According to the present invention, the thickness D3 of the shielding layer is 0.5 μm-2 μm.

[0019] In the present invention, the thicknesses of the connecting layer, the substrate layer and the shielding layer are measured by electron microscope observation and software processing.

[0020] According to the present invention, the elongation of the composite metal foil is 40%-120%.

[0021] According to the present invention, the tensile strength of the composite metal foil is 20kgf / mm 2 -30kgf / mm 2 .

[0022] In the present invention, a tensile testing machine is used to perform a tensile test on a sample to measure the elongation and tensile strength of the composite metal foil.

[0023] The second aspect of the present invention protects a method for preparing a composite metal foil, wherein the preparation method comprises the following steps:

[0024] forming a connecting layer on one surface of the substrate layer to obtain a composite substrate layer;

[0025] forming a shielding layer on a surface of the connecting layer away from the substrate layer;

[0026] Wherein, the melting range of the composite substrate layer is 120°C to 280°C.

[0027] According to the present invention, the connection layer is formed on the substrate layer by coating or co-extrusion with the substrate layer.

[0028] According to the present invention, the shielding layer is formed by at least one of lamination, electroplating, chemical plating and vacuum sputtering.

[0029] A third aspect of the present invention protects a cable material, which includes the aforementioned composite metal foil or the composite metal foil prepared by the aforementioned preparation method.

[0030] The technical solution of the present invention has the following advantages:

[0031] 1. The present invention provides a composite metal foil, wherein the composite metal foil comprises a composite substrate layer and a shielding layer which are stacked, the melting temperature of the composite substrate layer is 120°C to 280°C; the composite substrate layer comprises a connecting layer and a substrate layer which are stacked, the shielding layer is connected to the substrate layer through the connecting layer; the composite substrate layer and the shielding layer are tightly connected together, providing a stable structure and making the composite metal foil have excellent elongation and tensile strength, and at the same time, during welding, the composite substrate layer melts, so that the copper layer is exposed, having a good tinning area, and being able to ensure the production quality of the cable.

[0032] 2. When the bonding force between the composite substrate layer and the shielding layer in the present invention is greater than 0.4 N / cm, it can bring better structural stability, reduce or even avoid delamination and fracture of the substrate layer and the shielding layer during welding and winding.

[0033] 3. The specific thermal expansion coefficient of the composite substrate layer in the present invention can ensure that the connection layer material will not produce cracks or deformation during the welding temperature change process, and has excellent tin liquid resistance.

[0034] 5. In the present invention, when the thickness D1 of the substrate layer and the thickness D2 of the connecting layer satisfy 5μm≤D1+D2≤8μm, it can further ensure that the total thickness of the composite metal foil meets the use of cable materials, ensure the applicability of the use scenario, and at the same time improve the service life; when the thickness D1 of the substrate layer and the thickness D2 of the connecting layer satisfy 2μm≤D1 / D2≤7μm, it can bring a more uniform composite metal foil structure and further improve the structural stability.

[0035] 6. The present invention provides a method for preparing a composite metal foil, wherein the preparation method comprises the following steps: forming a connecting layer on one surface of a substrate layer to obtain a composite substrate layer; forming a shielding layer on a surface of the connecting layer away from the substrate layer; wherein the melting range of the composite substrate layer is 120°C to 280°C; the preparation method of the present invention is simple, and the prepared composite metal copper foil has excellent elongation and tinning area, thereby ensuring the production quality of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 This is a schematic structural diagram of a composite metal foil according to an embodiment 1 of the present invention;

[0038] Figure 2 This is a schematic structural diagram of a composite metal foil in Comparative Example 1 of the present invention;

[0039] Reference numerals: 1 - shielding layer; 2 - connecting layer; 3 - substrate layer; 4 - composite substrate layer. DETAILED DESCRIPTION

[0040] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0041] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0042] The tensile peel test was used to measure the bonding strength between the substrate layer and the shielding layer.

[0043] The weight average molecular weight of PET is 50,000 g / mol;

[0044] The weight average molecular weight of PI is 30000 g / mol;

[0045] The weight average molecular weight of the water-soluble epoxy resin is 3000 g / mol;

[0046] The weight average molecular weight of the polyamide is 6000 g / mol;

[0047] The weight average molecular weight of acrylic acid is 4000 g / mol.

[0048] Example 1

[0049] This embodiment provides a composite metal foil, which is as follows:

[0050] A water-soluble epoxy resin connecting layer is formed on one side of the PET substrate layer by coating, and a copper shielding layer is formed on the surface of the water-soluble epoxy resin connecting layer away from the PET substrate layer by vacuum sputtering and electroplating. The bonding force between the composite substrate layer and the shielding layer is 0.5 N / cm, the melting temperature of the composite substrate layer material is 140° C., and the thermal expansion coefficient is 40 ppm / ° C. The structural schematic diagram of Example 1 is shown in FIG. Figure 1 As shown, the stacked composite substrate layer and the shielding layer can be seen. The composite substrate layer includes a stacked connection layer and a substrate layer, and the shielding layer is connected to the substrate layer via the connection layer.

[0051] Example 2

[0052] This embodiment provides a composite metal foil, which is as follows:

[0053] Different from Example 1, a water-soluble epoxy resin connecting layer is formed on one surface of the PI substrate layer by coating, and a copper shielding layer is formed on the surface of the connecting layer away from the PET substrate layer by vacuum sputtering and electroplating. The bonding force between the composite substrate layer and the shielding layer is 0.56 N / cm, the melting point of the composite substrate layer material is 180°C, and the thermal expansion coefficient is 100 ppm / °C.

[0054] Example 3

[0055] This embodiment provides a composite metal foil, which is as follows:

[0056] A water-soluble epoxy resin and polyamide connecting layer is formed on one surface of the PET substrate layer by coating (wherein the mass ratio of the water-based epoxy resin to the polyurethane is 1:1), and a copper shielding layer is formed on the surface of the epoxy resin and polyamide connecting layer away from the PET substrate layer by vacuum sputtering and electroplating. The bonding force between the composite substrate layer and the shielding layer is 0.67 N / cm, the melting temperature of the composite substrate layer material is 150°C, and the thermal expansion coefficient is 90 ppm / °C.

[0057] Comparative Example 1

[0058] This comparative example provides a composite metal foil, which is as follows:

[0059] A copper shielding layer is formed on one side of the PET substrate layer by vacuum sputtering and electroplating. The bonding force between the substrate layer and the shielding layer is 0.21 N / cm. The melting temperature of the substrate layer material is 255° C., and the thermal expansion coefficient is 43 ppm / ° C. The structural schematic diagram of Comparative Example 1 is shown in FIG. Figure 2 As shown, the stacked substrate layer and the shielding layer can be seen, and there is no connecting layer in Comparative Example 1.

[0060] Comparative Example 2

[0061] This comparative example provides a composite metal foil, which is as follows:

[0062] An acrylic connecting layer is formed on one side of the PET substrate layer by coating, and a copper shielding layer is formed on the surface of the connecting layer away from the PET substrate layer by vacuum sputtering and electroplating. The bonding force between the composite substrate layer and the shielding layer is 0.28 N / cm, the melting temperature of the connecting layer material is 80°C, and the thermal expansion coefficient is 60 ppm / °C.

[0063] Comparative Example 3

[0064] This comparative example provides a composite metal foil, which is as follows:

[0065] A water-soluble epoxy resin connecting layer is formed on one surface of the PET substrate layer by coating, and a copper shielding layer is formed on the surface of the connecting layer away from the PET substrate layer by vacuum sputtering and electroplating. The bonding force between the composite substrate layer and the shielding layer is 0.25 N / cm, the melting temperature of the composite substrate layer is 350°C, and the thermal expansion coefficient is 180 ppm / °C.

[0066] Test Case

[0067] The thickness of each layer was detected by electron microscope observation and software processing; the details are shown in Table 1.

[0068] Table 1

[0069] <![CDATA[D1(μm)]]> <![CDATA[D2(μm)]]> <![CDATA[D3(μm)]]> <![CDATA[D1+D2(μm)]]> <![CDATA[D1 / D2(μm)]]> Example 1 6 1 1 7 6 Example 2 6 1 1 7 6 Example 3 4.5 1.5 1.5 6 3 Comparative Example 1 6 0 1 6 / Comparative Example 2 6 0.5 0.5 6.5 12 Comparative Example 3 4.5 2 1.5 6.5 2.25

[0070] The elongation at break and the tensile strength were tested using a tensile testing machine according to the tensile testing method, wherein the elongation was specifically calculated as follows: (total length at break - initial length) / initial length × 100%;

[0071] The melting area of ​​the composite substrate layer after tinning is detected by using visual software processing statistics. The specific method is: taking a photo sampling method to obtain an image of the outer side of the composite substrate layer after tinning, analyzing the obtained image by image processing software or program, and counting the area of ​​the tinned area (silver metal area) as the ratio of the melting area of ​​the substrate layer or the composite substrate layer;

[0072] The specific test results are shown in Table 2.

[0073] Table 2

[0074] Elongation(%) <![CDATA[Tensile strength (kgf / mm 2 )]]> Area of ​​tinning area (%) Example 1 94.35 24.35 90 Example 2 78.84 21.77 80 Example 3 108.24 26.54 70 Comparative Example 1 25.54 20.30 65 Comparative Example 2 61.1 21.84 35 Comparative Example 3 56.5 22.31 25

[0075] The composite metal foil prepared in the present invention has excellent elongation and tensile strength. At the same time, during welding, the composite base material layer melts, so that the copper layer is exposed, and has a good tinning area, which can ensure the production quality of the cable.

[0076] Comparison of Example 1 with Example 3 shows that when water-soluble epoxy resin and polyamide are selected for use together, the mechanical properties and tinning performance of the composite metal foil can be further improved.

[0077] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention.

Claims

1. A composite metal foil, characterized in that: The composite metal foil comprises a composite substrate layer and a shielding layer which are stacked, and the melting temperature of the composite substrate layer is 120° C. to 280° C.; The composite substrate layer includes a connection layer and a substrate layer which are stacked, and the shielding layer is connected to the substrate layer via the connection layer.

2. The composite metal foil according to claim 1, characterized in that: The melting temperature of the composite substrate layer is 140-200°C.

3. The composite metal foil according to claim 1, characterized in that: The bonding force between the composite substrate layer and the shielding layer is greater than 0.4 N / cm; And / or, the thermal expansion coefficient of the composite substrate layer is 40 ppm / °C to 140 ppm / °C.

4. The composite metal foil according to claim 1, characterized in that: The connecting layer material is a polymer material, including one or more of polyurethane, water-soluble epoxy resin, acrylic acid, polyamide, and phenolic resin, preferably a combination of water-soluble epoxy resin and polyurethane.

5. The composite metal foil according to claim 1, characterized in that: The thickness D1 of the substrate layer and the thickness D2 of the connecting layer satisfy the following: 5 μm ≤ D1 + D2 ≤ 8 μm; And / or, the thickness D1 of the substrate layer and the thickness D2 of the connecting layer satisfy: 2 μm≤D1 / D2≤7 μm.

6. The composite metal foil according to claim 1, characterized in that: The thickness D2 of the connecting layer is 1 μm-5 μm; and / or, the thickness D1 of the substrate layer is 4 μm-6 μm; And / or, the thickness D3 of the shielding layer is 0.5 μm-2 μm.

7. The composite metal foil according to claim 1, characterized in that: The elongation of the composite metal foil is 40%-120%; And / or, the tensile strength of the composite metal foil is 20kgf / mm 2 -30kgf / mm 2 .

8. A method for preparing a composite metal foil, characterized in that: The preparation method comprises the following steps: forming a connecting layer on one surface of the substrate layer to obtain a composite substrate layer; forming a shielding layer on a surface of the connecting layer away from the substrate layer; Wherein, the melting range of the composite substrate layer is 120°C to 280°C.

9. The preparation method according to claim 8, characterized in that: The connection layer is formed on the substrate layer by coating or co-extrusion with the substrate layer; And / or, the shielding layer is formed by at least one of lamination, electroplating, chemical plating and vacuum sputtering.

10. A cable material, characterized in that: The invention comprises the composite metal foil described in any one of claims 1 to 7 or the composite metal foil prepared by the preparation method described in claim 8 or 9.

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