A support for a metal foil and use thereof

Abstract

This invention provides a support for a metal foil and its application. The support is a thin-film layered structure, comprising a bright surface and a rough surface arranged opposite each other. The arithmetic mean roughness R(at) of any point X1 on the bright surface in the transverse direction satisfies the following relationship with the surface resistance Rs of any point X2: Rs = -211.06 × R(at). 2 +113.18×R(at)-14.075; the correlation coefficient of the relationship is r=0.9954, and the unit of R(at) is μm, and the unit of Rs is mΩ; X1 and X2 are the same location point or different location points. This invention improves the surface properties and subsequent processing performance of the metal foil by rationally controlling the surface roughness and surface resistance of the support body to adjust the surface roughness of the metal foil.

Description

Technical Field

[0001] This invention belongs to the field of battery manufacturing technology, and relates to a metal foil support, and more particularly to a metal foil support and its application. Background Technology

[0002] As a support for ultra-thin peelable metal foil (generally also called a conductive layer), the properties of the bright surface of this support, that is, the surface in contact with the release layer, including surface resistance and roughness, significantly affect the smooth electroplating deposition and surface morphology replication of the peelable metal foil. If the roughness of the bright surface of the support is too large, the roughness of the application surface (the surface closest to the bright surface of the support) of the ultra-thin peelable metal foil replicating that surface morphology will also increase. Consequently, when the metal foil is subsequently applied to a high-frequency circuit board, it is prone to severe skin effect, resulting in signal transmission impairment. However, if the roughness of the bright surface of the support is too small, the surface morphology will become further smoothed due to the adhesion of the release layer and the electroplating deposition of the metal foil. This results in the application surface roughness of the ultra-thin peelable metal foil replicating that surface morphology being significantly too low. Multiple roughening treatments are then required on the surface where the metal foil is bonded to the substrate to meet the morphology roughness requirements and improve the adhesion between the metal foil and the substrate. This process undoubtedly reduces product processing efficiency and increases processing costs.

[0003] Furthermore, those skilled in the art know that the surface resistivity of thin-film materials is significantly affected by the material's surface morphology, surface properties, and external temperature and humidity. However, how the surface properties of specific material surfaces, such as the glossy surface of the support, affect their surface resistivity is rarely studied. Therefore, researching the surface properties and surface resistivity of the glossy surface of the support is of significant application value for controlling these parameters within ideal ranges, thereby minimizing or even avoiding the adverse effects of the support's surface properties on the subsequent formation of ultra-thin peelable metal foils and improving the quality of ultra-thin peelable metal foils.

[0004] Currently, researchers have never properly controlled the surface roughness Rz of metal foils with different orientations of MD and TD to improve their surface smoothness. If the roughness fluctuation range of the metal foil is too large, i.e., the surface smoothness is poor, it will be difficult to complete the etching in one go in subsequent applications, such as the etching process in circuit board manufacturing, and may even lead to incomplete etching or local over-etching and open circuits. Therefore, proper control of the above parameters is crucial for improving the surface properties and subsequent processing performance of metal foils.

[0005] Therefore, how to provide a support for metal foil, and how to adjust the surface roughness of the metal foil by reasonably controlling the surface roughness and surface resistance of the support, thereby improving the surface properties and subsequent processing performance of the metal foil, has become an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a support for metal foil and its application. By reasonably controlling the surface roughness and surface resistance of the support, the surface roughness of the metal foil can be adjusted, thereby improving the surface properties and subsequent processing performance of the metal foil.

[0007] To achieve this objective, the present invention employs the following technical solution:

[0008] In a first aspect, the present invention provides a support for a metal foil, the support being a thin film layer structure comprising a bright surface and a rough surface disposed opposite to each other;

[0009] The arithmetic mean roughness R(at) of any point X1 on the bright surface in the transverse direction and the surface resistance Rs of any point X2 satisfy the following relationship:

[0010] Rs = -211.06 × R(at) 2 +113.18×R(at)-14.075

[0011] The correlation coefficient of the relationship is r = 0.9954, and the unit of R(at) is μm, and the unit of Rs is mΩ; X1 and X2 are the same location point or different location points.

[0012] This invention clarifies the correlation between the roughness of the polished surface of the support and the surface resistance by performing a function fitting. This facilitates the subsequent adjustment of the surface resistance by controlling the roughness of the polished surface of the support, thereby obtaining a support with an ideal surface resistance range.

[0013] Furthermore, by controlling the lateral roughness of the bright surface of the support within a reasonable range, the surface resistance of the application surface (the side closest to the bright surface of the support) of the ultrathin peelable metal foil that replicates its surface morphology can be predicted in advance. This ensures that when the ultrathin metal foil is subsequently deposited as a support for the release layer and ultrathin metal layer, its adverse effects on the surface morphology of the ultrathin metal layer are minimized. This results in an ultrathin metal layer with a reasonable surface morphology and surface resistance, meeting the requirements of high-frequency transmission and reducing signal loss. Simultaneously, this invention facilitates efficient prediction of the roughness of the bonding surface (the side furthest from the bright surface of the support) of the ultrathin peelable metal foil, allowing for the prior determination of the specific process and number of roughening treatments required. This facilitates optimization of the roughening process on the bonding surface of the ultrathin metal layer, thereby improving the adhesion performance between the metal foil and the circuit board substrate.

[0014] In this invention, the glossy surface and the rough surface have a significant difference in roughness, and the rough surface with higher roughness comes into contact with the conveyor roller, which increases the friction force, meets the conveying requirements, improves the conveying efficiency, and avoids problems such as slippage, skewing or wrinkling during the conveying process.

[0015] Preferably, R(at) in the relation satisfies 0.2μm≤R(at)≤0.34μm, for example, R(at) can be 0.2μm, 0.22μm, 0.24μm, 0.26μm, 0.28μm, 0.3μm, 0.32μm or 0.34μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0016] Preferably, Rs in the relation satisfies 0.45mΩ≤Rs≤1.1mΩ, for example, Rs can be 0.45mΩ, 0.5mΩ, 0.55mΩ, 0.6mΩ, 0.65mΩ, 0.7mΩ, 0.75mΩ, 0.8mΩ, 0.85mΩ, 0.9mΩ, 0.95mΩ, 1mΩ, 1.05mΩ or 1.1mΩ, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0017] This invention limits the surface resistance Rs of the bright surface of the support to a reasonable range, that is, limits the arithmetic mean roughness R(at) of the bright surface of the support in the transverse direction to a reasonable range, thereby affecting the ultra-thin peelable metal foil that replicates its surface morphology. This allows for indirect knowledge of the surface resistance range of the metal foil application surface, enabling reasonable control in advance, improving the quality of the metal foil, and synergistically reducing transmission loss when the metal foil is applied to a circuit board.

[0018] Preferably, the absolute value of the difference between the average roughness Rz(ta) in the transverse direction and the average roughness Rz(ma) in the longitudinal direction, |Rz(ta)-Rz(ma)|, is ≤0.5μm. For example, it can be 0.05μm, 0.1μm, 0.15μm, 0.2μm, 0.25μm, 0.3μm, 0.35μm, 0.4μm, 0.45μm, or 0.5μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0019] Preferably, the gloss of the glossy surface is 28-120 GU, for example, it can be 28 GU, 30 GU, 40 GU, 50 GU, 60 GU, 70 GU, 80 GU, 90 GU, 100 GU, 110 GU or 120 GU, more preferably 35-100 GU, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0020] Preferably, the absolute value of the difference between the average roughness Rz(tb) in the transverse direction and the average roughness Rz(mb) in the longitudinal direction, |Rz(tb)-Rz(mb)|, is ≤0.6μm. For example, it can be 0.05μm, 0.1μm, 0.15μm, 0.2μm, 0.25μm, 0.3μm, 0.35μm, 0.4μm, 0.45μm, 0.5μm, 0.55μm, or 0.6μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] This invention optimizes the roughness Rz of the bright and rough surfaces in the transverse and longitudinal directions, respectively, to ensure that the roughness of different orientations on both sides of the support body is close to each other, thereby ensuring the uniformity of different orientation roughness and the flatness of the surface, which is beneficial to further improving the quality and performance of the ultra-thin metal layer formed on the support body.

[0022] Preferably, the roughness Rz of the rough surface is 0.7-6.5 μm, for example, it can be 0.7 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm or 6.5 μm, more preferably 1.8-5 μm, but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0023] By limiting the roughness of the rough surface of the support body to a reasonable range, the present invention achieves the optimal contact effect between the rough surface and the conveying roller, further improving the conveying efficiency and avoiding problems such as slippage, skewing or wrinkling during the conveying process.

[0024] Preferably, the material of the support includes any one or a combination of at least two of copper, aluminum, zinc, nickel, chromium, iron, silver, gold, or stainless steel. Typical but non-limiting combinations include copper and aluminum, aluminum and zinc, zinc and nickel, nickel and chromium, chromium and iron, iron and silver, silver and gold, copper, aluminum and zinc, aluminum, zinc and nickel, zinc, nickel and chromium, nickel, chromium and iron, chromium, iron and silver, or iron, silver and gold.

[0025] Preferably, the thickness of the support is 3-25 μm, for example, it can be 3 μm, 4 μm, 6 μm, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm or 25 μm, more preferably 3-15 μm, and even more preferably 3-8 μm, but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0026] Preferably, the basis weight of the support is 1.2-3.5 g / dm³. 2 For example, it could be 1.2g / dm 2 1.4g / dm 2 1.6g / dm 2 1.8g / dm 2 2.0g / dm 2 2.2g / dm 2 2.4g / dm 2 2.6g / dm 2 2.8g / dm 2 3.0g / dm 2 3.2g / dm 2 3.4g / dm 2 Or 3.5g / dm 2 Further preferred values ​​are 1.2-2.0 g / dm³. 2 However, this does not apply to all values ​​listed; other unlisted values ​​within the same range also apply.

[0027] This invention limits the thickness and weight of the support body to a reasonable range, which helps to reduce product weight and manufacturing costs while taking into account product performance.

[0028] In a second aspect, the present invention provides a metal foil comprising a support as described in the first aspect, the metal foil comprising a support and a metal layer stacked together, wherein the metal layer is disposed on the same side of the bright surface of the support.

[0029] Preferably, the ratio of the roughness of the surface of the metal layer near the support to the roughness of the rough surface in the support is 0.94-1.06, for example, it can be 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1.01, 1.02, 1.03, 1.04, 1.05 or 1.06, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0030] Preferably, the metal layer is made of copper.

[0031] Preferably, a release layer is further provided between the support and the metal layer.

[0032] This invention provides a release layer between the support and the metal layer, ensuring appropriate adhesive strength between them and facilitating subsequent peeling while retaining a certain degree of adhesion to prevent delamination of the metal foil during hot pressing.

[0033] Preferably, the material of the release layer includes metal and / or non-metal.

[0034] Preferably, the metal comprises any one or a combination of at least two of zinc, nickel, cadmium, copper, molybdenum, titanium, or niobium. Typical but non-limiting combinations include combinations of zinc and nickel, nickel and cadmium, cadmium and copper, copper and molybdenum, molybdenum and titanium, titanium and niobium, zinc, nickel and cadmium, nickel, cadmium and copper, cadmium, copper and molybdenum, copper, molybdenum and titanium, or molybdenum, titanium, and niobium.

[0035] Preferably, the non-metal includes any one or a combination of at least two of silicon, graphite, or organic polymer materials. Typical but non-limiting combinations include combinations of silicon and graphite, graphite and organic polymer materials, silicon and organic polymer materials, or silicon, graphite, and organic polymer materials.

[0036] In this invention, the organic polymer material is a conventionally used organic polymer material in the art, such as polyethylene, polypropylene, polyvinyl chloride or polyester film, as long as it can be used as a release layer, so no specific type is particularly limited here.

[0037] In this invention, when the material of the release layer is non-metallic, it can be in the form of a release layer, and the release layer includes any one of a silicone-free release layer, a silicone oil release layer, or a nitrogen-based release layer. The specific material can be HDPE (high-density polyethylene) and PMA (propylene glycol methyl ether acetate) solvent, etc.; the release layer can be formed by coating and drying a release agent.

[0038] Preferably, the thickness of the release layer is 1-8 nm, for example, it can be 1 nm, 1.5 nm, 2 nm, 2.5 nm, 3 nm, 3.5 nm, 4 nm, 4.5 nm, 5 nm, 5.5 nm, 6 nm, 6.5 nm, 7 nm, 7.5 nm or 8 nm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0039] Preferably, the support and / or the release layer are filled with a heat-absorbing medium.

[0040] This invention fills the support and / or release layer with a heat-absorbing medium, so that when the metal foil is hot-pressed onto the circuit board substrate or as a negative electrode material of a new energy battery and hot-pressed to bond with the negative electrode active material, the heat-absorbing medium absorbs heat in time, reducing the heat on the bonding surface of the metal layer, thereby avoiding phenomena such as blistering, wrinkling or cracking of the metal foil during the bonding process.

[0041] Preferably, the heat-absorbing medium comprises filler particles.

[0042] Preferably, the filler particles include any one or a combination of at least two of carbon nanoparticles, carbon nanotubes, or carbon nanofibers. Typical but non-limiting combinations include combinations of carbon nanoparticles and carbon nanotubes, combinations of carbon nanotubes and carbon nanofibers, combinations of carbon nanoparticles and carbon nanofibers, or combinations of carbon nanoparticles, carbon nanotubes, and carbon nanofibers, and more preferably carbon nanofibers.

[0043] In this invention, the carbon nanofibers are lightweight and have good thermal conductivity, and can form a skeleton structure as a heat exchange medium, which further enhances the strength of the support.

[0044] In this invention, the filler particles can be spherical, teardrop-shaped, triangular, sheet-like, strip-shaped, or other shapes, as long as they can fill the support and / or release layer and play a heat-absorbing role. Therefore, their specific shape is not particularly limited here.

[0045] Preferably, an adhesive layer is further provided between the support and the release layer.

[0046] This invention facilitates a tight bond between the support and the release layer by providing an adhesive layer between them. During peeling, the release layer, adhesive layer, and support are peeled off together from the surface of the ultra-thin metal layer, ensuring that the release layer does not remain on one side of the ultra-thin metal layer. This reduces the volume resistivity of the ultra-thin metal layer, thereby mitigating current loss and heat generation when applied to circuit boards, and improving the circuit's conductivity and safety.

[0047] In addition, the presence of the adhesive layer and the release layer can cover the uneven surface of the support, making the metal layer formed on the side of the release layer away from the adhesive layer smoother, more uniform and denser, reducing the number of pinholes and facilitating the subsequent circuit fabrication process.

[0048] Preferably, the adhesive layer is made of metal and / or non-metal.

[0049] Preferably, the metal includes any one or a combination of at least two of copper, zinc, nickel, iron, or manganese. Typical but non-limiting combinations include combinations of copper and zinc, zinc and nickel, nickel and iron, iron and manganese, copper, zinc, and nickel, zinc, nickel, and iron, or nickel, iron, and manganese.

[0050] Preferably, the non-metallic material comprises thermoplastic resin and / or thermosetting resin.

[0051] In this invention, the thermoplastic resin is a thermoplastic resin conventionally used in the art, such as polystyrene, vinyl acetate, polyester, polyethylene, polyamide, rubber, or acrylate thermoplastic resin; similarly, the thermosetting resin is a thermosetting resin conventionally used in the art, such as phenolic, epoxy, thermoplastic polyimide, urethane, melamine, or alkyd thermosetting resin.

[0052] Thirdly, the present invention provides an application of the support as described in the first aspect, the application including using the support for any one of the following: fabrication of a laminated copper plate, a printed circuit board, or a battery negative electrode current collector.

[0053] Specifically, when the support provided by the present invention is used to prepare a copper-clad laminate, a metal layer is formed on the support, and a composite metal foil containing the support and the metal foil is bonded to the substrate by hot pressing; when the support provided by the present invention is used to prepare a printed circuit board, a metal layer is formed on the support, and a composite metal foil containing the support and the metal layer is bonded to the substrate by hot pressing to form a copper-clad laminate, the support is removed, and the desired circuit pattern is formed on the metal layer by etching; when the support provided by the present invention is used to prepare a battery negative electrode current collector, a metal layer is formed on the support, a battery negative electrode active material is coated on the metal layer, the support is removed, and the metal layer is used as the negative electrode current collector.

[0054] The metal layer formed on the support can be achieved using conventional techniques in the art, such as electroplating.

[0055] Furthermore, when the support is used in the preparation of the negative electrode current collector of a battery, the surface morphology and surface resistance of the metal layer can be indirectly controlled and predicted through roughness. This facilitates the early prediction of its performance as a negative electrode current collector. Simultaneously, by optimizing its surface properties, including suitable roughness, the adhesion between the current collector and the negative electrode active material is improved, preventing problems such as increased internal battery losses, reduced energy density, and insufficient safety and stability caused by active material detachment. At the same time, predicting and controlling the surface resistance of the metal layer helps reduce the battery's internal resistance, thereby improving electrochemical reaction efficiency and energy density.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] (1) This invention clarifies the correlation between the roughness of the bright surface of the support and the surface resistance by fitting the relationship between the two parameters, which makes it easier to adjust the surface resistance by controlling the roughness of the bright surface of the support, thereby obtaining a support with an ideal surface resistance range.

[0058] (2) By controlling the roughness of the bright surface of the support in the transverse direction within a reasonable range, the present invention can predict in advance the surface resistance of the application surface (the side surface near the bright surface of the support) of the ultrathin peelable metal foil that replicates its surface morphology. This ensures that when it is used as a support to deposit the release layer and the ultrathin metal layer, the adverse effect on the surface morphology of the ultrathin metal layer is minimized, thereby obtaining an ultrathin metal layer with reasonable surface morphology and reasonable surface resistance, which meets the requirements of high-frequency transmission and reduces signal loss.

[0059] (3) The present invention is beneficial to efficiently predict the roughness of the bonding surface (the side surface away from the bright surface of the support) of the ultrathin peelable metal foil, thereby determining the specific process and number of roughening treatments required in advance, which facilitates the optimization of the roughening treatment process on the bonding surface of the ultrathin metal layer, thereby improving the bonding performance between the metal foil and the circuit board substrate. Attached Figure Description

[0060] Figure 1 These are schematic diagrams of the metal foil structure including the support provided in Examples 1-4.

[0061] Wherein, 1-support; 2-adhesive layer; 3-release layer; 4-metal layer. Detailed Implementation

[0062] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0063] Example 1

[0064] This embodiment provides a metal foil including a support, such as Figure 1 As shown, the metal foil includes a support 1, an adhesive layer 2, a release layer 3, and a metal layer 4 stacked sequentially; the support 1 is a thin film layer structure, including a bright surface and a rough surface arranged opposite to each other, and the metal layer 4 is disposed on the same side of the bright surface of the support 1.

[0065] Specifically, the arithmetic mean roughness R(at) of a certain point X1 on the bright surface of the support 1 in the transverse direction and the surface resistance Rs of a certain point X2 are shown in Table 1 (X1 and X2 are different points); the absolute value of the difference between the average roughness Rz(ta) in the transverse direction and the average roughness Rz(ma) in the longitudinal direction of the bright surface |Rz(ta)-Rz(ma)|=0.3μm, and the gloss of the bright surface is 50GU; the absolute value of the difference between the average roughness Rz(tb) in the transverse direction and the average roughness Rz(mb) in the longitudinal direction of the rough surface |Rz(tb)-Rz(mb)|=0.5μm, and the roughness of the rough surface is 1.3μm; the material of the support 1 is stainless steel, with a thickness of 8μm and a basis weight of 1.8g / dm. 2 .

[0066] In this embodiment, the adhesive layer 2 is made of BT resin and has a thickness of 3 nm; the release layer 3 is made of graphite and has a thickness of 4 nm; the support 1 and the release layer 3 are respectively filled with carbon nanofibers as heat-absorbing media; the metal layer 4 is made of copper, and its thickness D, surface roughness Rz on the side near the release layer 3, thickness uniformity and peelability are shown in Table 1.

[0067] Example 2

[0068] This embodiment provides a metal foil including a support, such as Figure 1 As shown, the metal foil includes a support 1, an adhesive layer 2, a release layer 3, and a metal layer 4 stacked sequentially; the support 1 is a thin film layer structure, including a bright surface and a rough surface arranged opposite to each other, and the metal layer 4 is disposed on the same side of the bright surface of the support 1.

[0069] Specifically, the arithmetic mean roughness R(at) of a certain point X1 on the bright surface of the support 1 in the transverse direction and the surface resistance Rs of a certain point X2 are shown in Table 1 (X1 and X2 are different points); the absolute value of the difference between the average roughness Rz(ta) in the transverse direction and the average roughness Rz(ma) in the longitudinal direction of the bright surface, |Rz(ta)-Rz(ma)| = 0.2 μm, and the gloss of the bright surface is 86 GU; the absolute value of the difference between the average roughness Rz(tb) in the transverse direction and the average roughness Rz(mb) in the longitudinal direction of the rough surface, |Rz(tb)-Rz(mb)| = 0.4 μm, and the roughness of the rough surface is 1.5 μm; the support 1 is made of nickel-copper alloy, with a thickness of 10 μm and a basis weight of 2.2 g / dm. 2 .

[0070] In this embodiment, the adhesive layer 2 is made of ABF resin and has a thickness of 4 nm; the release layer 3 is made of silicon and has a thickness of 5 nm; carbon nanofibers are filled in the support 1 and the release layer 3 as heat-absorbing media; the metal layer 4 is made of copper, and its thickness D, surface roughness Rz on the side near the release layer 3, thickness uniformity and peelability are shown in Table 1.

[0071] Example 3

[0072] This embodiment provides a metal foil including a support, such as Figure 1 As shown, the metal foil includes a support 1, an adhesive layer 2, a release layer 3, and a metal layer 4 stacked sequentially; the support 1 is a thin film layer structure, including a bright surface and a rough surface arranged opposite to each other, and the metal layer 4 is disposed on the same side of the bright surface of the support 1.

[0073] Specifically, the arithmetic mean roughness R(at) of a certain point X1 on the bright surface of the support 1 in the transverse direction and the surface resistance Rs of a certain point X2 are shown in Table 1 (X1 and X2 are different points); the absolute value of the difference between the average roughness Rz(ta) in the transverse direction and the average roughness Rz(ma) in the longitudinal direction of the bright surface, |Rz(ta)-Rz(ma)| = 0.4 μm, and the gloss of the bright surface is 35 GU; the absolute value of the difference between the average roughness Rz(tb) in the transverse direction and the average roughness Rz(mb) in the longitudinal direction of the rough surface, |Rz(tb)-Rz(mb)| = 0.5 μm, and the roughness of the rough surface is 1.7 μm; the support 1 is made of copper-zinc alloy, with a thickness of 15 μm and a basis weight of 3.2 g / dm. 2 .

[0074] In this embodiment, the adhesive layer 2 is made of BT resin and has a thickness of 2nm; the release layer 3 is made of polypropylene and has a thickness of 3nm; carbon nanotubes are filled in the support 1 and the release layer 3 as heat-absorbing media; the metal layer 4 is made of copper, and its thickness D, surface roughness Rz on the side near the release layer 3, thickness uniformity and peelability are shown in Table 1.

[0075] Example 4

[0076] This embodiment provides a metal foil including a support, such as Figure 1 As shown, the metal foil includes a support 1, an adhesive layer 2, a release layer 3, and a metal layer 4 stacked sequentially; the support 1 is a thin film layer structure, including a bright surface and a rough surface arranged opposite to each other, and the metal layer 4 is disposed on the same side of the bright surface of the support 1.

[0077] Specifically, the arithmetic mean roughness R(at) of a certain point X1 on the bright surface of the support 1 in the transverse direction and the surface resistance Rs of a certain point X2 are shown in Table 1 (X1 and X2 are different points); the absolute value of the difference between the average roughness Rz(ta) in the transverse direction and the average roughness Rz(ma) in the longitudinal direction of the bright surface, |Rz(ta)-Rz(ma)|=0.5μm, and the gloss of the bright surface is 28GU; the absolute value of the difference between the average roughness Rz(tb) in the transverse direction and the average roughness Rz(mb) in the longitudinal direction of the rough surface, |Rz(tb)-Rz(mb)|=0.6μm, and the roughness of the rough surface is 1.6μm; the support 1 is made of iron-nickel alloy, with a thickness of 20μm and a basis weight of 3.5g / dm. 2 .

[0078] In this embodiment, the adhesive layer 2 is made of ABF resin and has a thickness of 3 nm; the release layer 3 is made of graphite and has a thickness of 3 nm; carbon nanospheres are filled in the support 1 and the release layer 3 as heat-absorbing media; the metal layer 4 is made of copper, and its thickness D, surface roughness Rz on the side near the release layer 3, thickness uniformity and peelability are shown in Table 1.

[0079] Example 5

[0080] This embodiment provides a metal foil containing a support. Except for removing the adhesive layer 2, the metal foil includes a support 1, a release layer 3 and a metal layer 4 stacked in sequence. All other conditions are the same as in embodiment 1, so they will not be described in detail here.

[0081] Comparative Example 1

[0082] This comparative example provides a metal foil including a support, and the differences between the metal foil and the metal foil provided in Example 1 are as follows:

[0083] The arithmetic mean roughness R(at) of a certain position X1 on the bright surface of the support body 1 in the transverse direction and the surface resistance Rs of a certain position X2 are shown in Table 1 (X1 and X2 are different positions); the absolute value of the difference between the average roughness Rz(ta) in the transverse direction and the average roughness Rz(ma) in the longitudinal direction of the bright surface |Rz(ta)-Rz(ma)|=0.7μm, and the gloss of the bright surface is 20GU; the absolute value of the difference between the average roughness Rz(tb) in the transverse direction and the average roughness Rz(mb) in the longitudinal direction of the rough surface |Rz(tb)-Rz(mb)|==0.7μm, and the roughness of the rough surface is 6μm; the other features are the same as in Example 1, so they will not be described in detail here.

[0084] Table 1

[0085]

[0086] In the table above, the uniformity of the metal layer thickness was observed by scanning electron microscopy and thickness testing to check the smoothness of the slice thickness and morphology; the peelability of the metal layer was determined by manually peeling off the carrier, repeating the process 10 times for each sample, and observing and recording the peeling results.

[0087] As shown in Table 1, the metal foils provided in Examples 1-5 have better uniformity of metal layer thickness and peelability than Comparative Example 1. Compared with Comparative Example 1, Examples 1-5 have lower surface resistance of the support when the metal layer thickness is similar, and the surface roughness of the metal layer formed on it near the release layer is also lower, which fully meets the requirement of reducing transmission loss when applied to high-frequency circuit boards.

[0088] Therefore, this invention clarifies the correlation between the roughness of the polished surface of the support and the surface resistance by performing a function fitting, which facilitates the subsequent adjustment of the surface resistance by controlling the roughness of the polished surface of the support, thereby obtaining a support with an ideal surface resistance range.

[0089] Furthermore, by controlling the roughness of the bright surface of the support within a reasonable range, this invention allows for the prediction of the surface resistance of the application surface (the side closest to the bright surface of the support) of the ultrathin peelable metal foil that replicates its surface morphology. This ensures that the adverse effects on the surface morphology of the ultrathin metal layer are minimized when it is subsequently deposited as a support for the release layer and ultrathin metal layer. This results in an ultrathin metal layer with a reasonable surface morphology and surface resistance, meeting high-frequency transmission requirements and reducing signal loss. Simultaneously, this invention facilitates efficient prediction of the roughness of the bonding surface (the side furthest from the bright surface of the support) of the ultrathin peelable metal foil, allowing for the prior determination of the specific process and number of roughening treatments required. This facilitates optimization of the roughening process on the bonding surface of the ultrathin metal layer, thereby improving the adhesion performance between the metal foil and the circuit board substrate.

[0090] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A support for a metal foil, characterized in that, The support is a thin film layered structure, including a glossy surface and a rough surface arranged opposite to each other; The arithmetic mean roughness R(at) of any point X1 on the bright surface in the transverse direction and the surface resistance Rs of any point X2 satisfy the following relationship: The correlation coefficient of the relationship is r=0.9954, and the unit of R(at) is μm, and the unit of Rs is mΩ; X1 and X2 are the same location point or different location points.

2. The support according to claim 1, characterized in that, In the given expression, R(at) satisfies 0.2μm≤R(at)≤0.34μm.

3. The support according to claim 1, characterized in that, The Rs in the relation satisfies 0.45mΩ≤Rs≤1.1mΩ.

4. The support according to claim 1, characterized in that, The gloss level of the glossy surface is 28-120 GU.

5. The support according to claim 4, characterized in that, The gloss level of the glossy surface is 35-100 GU.

6. The support according to claim 1, characterized in that, The roughness Rz of the rough surface is 0.7-6.5 μm.

7. The support according to claim 6, characterized in that, The roughness Rz of the rough surface is 1.8-5 μm.

8. The support according to claim 1, characterized in that, The material of the support includes any one or a combination of at least two of the following: copper, aluminum, zinc, nickel, chromium, iron, silver, gold, or stainless steel.

9. The support according to claim 1, characterized in that, The thickness of the support is 3-25 μm.

10. The support according to claim 9, characterized in that, The thickness of the support is 3-15 μm.

11. The support according to claim 10, characterized in that, The thickness of the support is 3-8 μm.

12. The support according to claim 1, characterized in that, The support has a grammage of 1.2-3.5 g / dm 2 .

13. The support according to claim 12, characterized in that, The support has a grammage of 1.2-2.0 g / dm 2 .

14. A metal foil comprising a support as described in any one of claims 1-13, characterized in that, The metal foil includes a support body and a metal layer stacked together, and the metal layer is disposed on the same side of the bright surface of the support body.

15. The metal foil according to claim 14, characterized in that, The metal layer is made of copper.

16. The metal foil according to claim 14, characterized in that, A release layer is also provided between the support and the metal layer.

17. The metal foil according to claim 16, characterized in that, The material of the release layer includes metal and / or non-metal.

18. The metal foil according to claim 17, characterized in that, The metal includes any one or a combination of at least two of zinc, nickel, cadmium, copper, molybdenum, titanium, or niobium.

19. The metal foil according to claim 17, characterized in that, The non-metals include any one or a combination of at least two of silicon, graphite, or organic polymer materials.

20. The metal foil according to claim 16, characterized in that, The thickness of the release layer is 1-8 nm.

21. The metal foil according to claim 16, characterized in that, The support and / or the release layer are filled with a heat-absorbing medium.

22. The metal foil according to claim 21, characterized in that, The heat-absorbing medium includes filler particles.

23. The metal foil according to claim 22, characterized in that, The filler particles include any one or a combination of at least two of carbon nanoparticles, carbon nanotubes, or carbon nanofibers.

24. The metal foil according to claim 23, characterized in that, The filler particles are carbon nanofibers.

25. The metal foil according to claim 16, characterized in that, An adhesive layer is also provided between the support and the release layer.

26. The metal foil according to claim 25, characterized in that, The adhesive layer is made of metal and / or non-metal.

27. The metal foil according to claim 26, characterized in that, The metal includes any one or a combination of at least two of copper, zinc, nickel, iron, or manganese.

28. The metal foil according to claim 26, characterized in that, The non-metals include thermoplastic resins and / or thermosetting resins.

29. An application of the support as described in any one of claims 1-13, characterized in that, The applications include using the support to prepare any one of a laminated copper plate, a printed circuit board, or a battery negative electrode current collector.

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