Electromagnetic shielding composite film

Abstract

The utility model relates to an electromagnetic shielding composite film which comprises a low-density graphite layer and at least one high-density graphite layer, the low-density graphite layer and the high-density graphite layer are bonded through a double-sided adhesive layer, a plurality of expansion holes are formed in the low-density graphite layer, and a plurality of convex structures are arranged on the side face, away from the double-sided adhesive layer, of the low-density graphite layer. The electromagnetic shielding composite film has good flexibility, conductivity and electromagnetic shielding performance, is suitable for assembly of electronic components with special-shaped or boss structures, and is wide in application range; and the adhesive can be stably attached to electronic components, and has good electromagnetic wave interference resistance and heat dissipation performance.

Description

Technical Field

[0001] This application relates to the field of electromagnetic shielding materials, and in particular to an electromagnetic shielding composite film. Background Technology

[0002] During the assembly process, electronic components need to be covered with a layer of electromagnetic shielding material. The electromagnetic shielding material can effectively shield the electromagnetic waves generated inside the electronic components, avoiding interference with the surrounding environment and other equipment. At the same time, it can also prevent external electromagnetic waves from entering the electronic components and causing electromagnetic interference, thereby affecting the normal operation of the electronic components.

[0003] Currently, commonly used electromagnetic shielding materials are generally conductive foam or conductive lining. Conductive foam is lightweight and easy to install and use, but its electromagnetic shielding effect is relatively poor. Conductive lining is generally made of woven conductive metal wires, which has a better electromagnetic shielding effect, but its overall density is high, resulting in poor adhesion during the assembly of electronic components with irregular shapes or protrusions, and also poor heat dissipation performance for electronic components. Therefore, further research is needed on the electromagnetic shielding materials currently in use. Utility Model Content

[0004] To address the issues of low electromagnetic shielding performance, poor bonding performance in the assembly of electronic components with irregular or protruding structures, and low heat dissipation performance of existing electromagnetic shielding materials, this application provides an electromagnetic shielding composite film.

[0005] This application provides an electromagnetic shielding composite film, which adopts the following technical solution:

[0006] An electromagnetic shielding composite film includes a low-density graphite layer and at least one high-density graphite layer, wherein the low-density graphite layer and the high-density graphite layer are bonded together by a double-sided adhesive layer, wherein the low-density graphite layer has a plurality of expansion holes, and wherein the side of the low-density graphite layer away from the double-sided adhesive layer has a plurality of convex structures.

[0007] By adopting the above technical solutions, the convex structure of the low-density graphite layer gives it a larger specific surface area, which increases the contact area with electromagnetic waves and attenuates them through multiple reflections, thus improving the electromagnetic shielding effect. The inclusion of several expansion holes in the low-density graphite layer further increases the multiple reflections and dissipation of internal electromagnetic waves, further enhancing the electromagnetic shielding performance. The high-density graphite layer, with its dense graphite structure, can reflect electromagnetic waves and effectively dissipate heat from electromagnetic waves and electronic components. By using double-sided adhesive to stably bond low-density graphite layers and high-density graphite layers, during bonding, the high-density graphite layer is close to and covers the electronic components, while the low-density and high-density graphite layers work together to reflect and shield external electromagnetic waves and prevent internal electromagnetic waves from interfering with other electronic components. The resulting electromagnetic shielding composite film has good flexibility and conductivity, good bonding stability to electronic components, and good anti-electromagnetic interference and heat dissipation performance. It is suitable for assembling flat electronic components as well as electronic components with irregular shapes or protruding structures, and has a wide range of applications.

[0008] Preferably, an adhesive layer is provided on the side of the high-density graphite layer away from the double-sided adhesive layer.

[0009] By adopting the above technical solution, the adhesive layer enables the electromagnetic shielding composite film to be directly bonded and fixed to electronic components, improving the convenience and stability in practical applications.

[0010] Preferably, the high-density graphite layer is configured as two layers, and the two high-density graphite layers are bonded together by the adhesive layer.

[0011] By adopting the above technical solution, the addition of two high-density graphite layers increases the multiple reflections and absorption of electromagnetic waves, thereby further improving the electromagnetic shielding performance of the electromagnetic shielding composite film. The adhesive layer plays a good bonding role, which can improve the structural stability between the two high-density graphite layers.

[0012] Preferably, at least one side of the high-density graphite layer is provided with a first copper plating layer.

[0013] By adopting the above technical solution, the first copper plating layer can improve the conductivity of the electromagnetic shielding composite film, enhance its ability to reflect and absorb electromagnetic waves, thereby effectively reducing the penetration of electromagnetic waves and further improving the electromagnetic interference resistance of the electromagnetic shielding composite film. Simultaneously, it can further improve the bonding stability between the double-sided adhesive layer and / or the adhesive layer and the high-density graphite layer. Because the polarity difference between the high-density graphite layer and the double-sided adhesive layer and / or the adhesive layer is significant, the electromagnetic shielding composite film is prone to delamination or bulging and bubble problems during the assembly of electronic components with irregular shapes or protruding structures. The surface of the first copper plating layer is prone to oxidation, which can enhance the bonding stability between the high-density graphite layer and the double-sided adhesive layer and / or the adhesive layer.

[0014] Preferably, a second copper plating layer is provided on the side of the low-density graphite layer near the double-sided adhesive layer.

[0015] By adopting the above technical solution, the second copper plating layer can further improve the conductivity and electromagnetic wave reflection capability of the electromagnetic shielding composite film, thereby enhancing the shielding effect against electromagnetic waves. Simultaneously, the second copper plating layer can also improve the adhesion stability between the double-sided adhesive layer and the low-density graphite layer, making the resulting electromagnetic shielding composite film more suitable for assembling electronic components with irregular shapes or protruding structures, and reducing the likelihood of problems such as delamination, bulging, and bubbles during bonding.

[0016] Preferably, the thickness of both the first copper plating layer and the second copper plating layer is 0.1-5µm.

[0017] By adopting the above technical solution, the optimal thickness of the first and second copper plating layers can significantly improve the conductivity and electromagnetic shielding effect of the electromagnetic shielding composite film. If the thickness is too thick, the overall thickness of the electromagnetic shielding composite film will increase, reducing its flexibility and consequently decreasing its bonding stability and increasing costs; if the thickness is too thin, the electromagnetic shielding performance of the electromagnetic shielding composite film will decrease.

[0018] Preferably, the plurality of the convex structures are arranged in a wave-like shape, and the height of the convex structures is 1-10µm.

[0019] By adopting the above technical solution, the convex structure with its wave-like arrangement can increase the contact area with electromagnetic waves, thereby improving the multiple reflections and attenuation effects of electromagnetic waves and effectively enhancing electromagnetic shielding performance. The height of the convex structure is controlled within the range of 1-10µm to ensure that the structural dimensions are moderate. Without affecting the overall thickness, the reflection path of electromagnetic waves is further optimized, improving electromagnetic shielding efficiency.

[0020] Preferably, the thickness of the low-density graphite layer is 30-500µm.

[0021] By adopting the above technical solution, the low-density graphite layer of optimal thickness enables the electromagnetic shielding composite film to maintain good mechanical strength while also possessing excellent flexibility. It can fully form an expansion pore structure, thereby enhancing the multi-reflection dissipation effect on electromagnetic waves and further improving electromagnetic shielding performance.

[0022] Preferably, the double-sided adhesive layer contains a plurality of conductive particles, and the thickness of the double-sided adhesive layer is 3-30µm.

[0023] By employing the above technical solution, conductive particles are incorporated into the double-sided adhesive layer, enabling it to function as both an adhesive and possess high electrical and magnetic permeability. This further enhances the electromagnetic shielding composite film's ability to reduce electromagnetic wave conduction and magnetic losses. Controlling the thickness of the double-sided adhesive layer within the range of 3-30µm ensures that it exhibits both excellent adhesive properties and good electromagnetic wave dissipation performance.

[0024] Preferably, the thickness of the high-density graphite layer is 17-150µm.

[0025] By adopting the above technical solution, the thickness of the high-density graphite layer is set to 17-150µm, ensuring that the electromagnetic shielding composite film has good mechanical strength and flexibility, while also maintaining excellent electromagnetic shielding performance. It can work synergistically with the low-density graphite layer and double-sided adhesive layer to ensure the stability of the overall structure, making it suitable for assembling electronic components with irregular shapes or protruding structures, further improving the shielding effect and heat dissipation performance against electromagnetic waves.

[0026] In summary, this application includes at least one of the following beneficial technical effects:

[0027] 1. The electromagnetic shielding composite film of this application comprises a low-density graphite layer, a double-sided adhesive layer, and a high-density graphite layer. The low-density graphite layer contains expansion holes and a convex structure on the side away from the double-sided adhesive layer. The convex structure increases the contact area with electromagnetic waves and achieves multiple reflection attenuation. The internal expansion hole structure further promotes the multiple reflection dissipation of electromagnetic waves. The high-density graphite layer reflects electromagnetic waves and also effectively dissipates heat from electromagnetic waves and electronic components. The resulting electromagnetic shielding composite film can reflect and shield external electromagnetic waves while preventing internal electromagnetic waves from interfering with other electronic components. It exhibits good flexibility, electromagnetic interference resistance, and heat dissipation performance, and provides good bonding stability to electronic components. It is suitable for assembling flat electronic components as well as those with irregular shapes or protruding structures, making it widely applicable.

[0028] 2. By setting the high-density graphite layer to two layers, the electromagnetic shielding performance of the electromagnetic shielding composite film is further improved.

[0029] 3. By setting a first copper plating layer between the high-density graphite layer and the double-sided adhesive layer and / or adhesive layer, the conductivity of the electromagnetic shielding composite film can be improved, the reflection and absorption of electromagnetic waves can be enhanced, the anti-electromagnetic interference performance of the electromagnetic shielding composite film can be further improved, and the bonding stability between the double-sided adhesive layer and / or adhesive layer and the high-density graphite layer can also be further improved.

[0030] 4. By setting a second copper plating layer between the low-density graphite layer and the double-sided adhesive layer, the conductivity of the electromagnetic shielding composite film can be further improved, enhancing its anti-electromagnetic interference performance. At the same time, the bonding stability between the double-sided adhesive layer and the low-density graphite layer can also be further improved.

[0031] 5. By setting the convex structure in a wave shape, the contact area with electromagnetic waves can be increased, thereby improving the multiple reflection and attenuation performance of electromagnetic waves, and thus enhancing the electromagnetic shielding performance. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the layer structure of an electromagnetic shielding composite film according to Embodiment 1 of this application.

[0033] Figure 2 This is a schematic diagram of the layer structure of an electromagnetic shielding composite film according to Embodiment 2 of this application.

[0034] Figure 3 This is a schematic diagram of the layer structure of an electromagnetic shielding composite film according to Embodiment 3 of this application.

[0035] Figure 4 This is a schematic diagram of the layer structure of an electromagnetic shielding composite film according to Embodiment 4 of this application.

[0036] Figure 5 This is a schematic diagram of the layer structure of an electromagnetic shielding composite film according to Embodiment 5 of this application.

[0037] Explanation of reference numerals in the attached drawings: 1. Low-density graphite layer; 11. Expansion hole; 2. Double-sided adhesive layer; 3. High-density graphite layer; 4. Convex structure; 5. Adhesive layer; 6. First copper plating layer; 7. Second copper plating layer. Detailed Implementation

[0038] The following is in conjunction with the appendix Figure 1-5 This application will be described in further detail. Example 1

[0039] Example 1 discloses an electromagnetic shielding composite film.

[0040] Reference Figure 1An electromagnetic shielding composite film includes a low-density graphite layer 1, a double-sided adhesive layer 2, and at least one high-density graphite layer 3, wherein the low-density graphite layer 1 and the high-density graphite layer 3 are bonded together by the double-sided adhesive layer 2. Specifically, the low-density graphite layer 1 is obtained by carbonizing and graphitizing a polyimide film, followed by intercalation and expansion foaming, and the true density of the low-density graphite layer 1 is less than 2.0 g / cm³. 3 The low-density graphite layer 1 has a plurality of expansion holes 11 inside; the thickness of the low-density graphite layer 1 is 30-500µm, preferably, the thickness of the low-density graphite layer 1 can be 30µm, 40µm, 50µm, 60µm, 70µm, 80µm, 90µm, 100µm, 125µm, 150µm, 200µm, 250µm, 300µm, 350µm, 400µm, 450µm or 500µm, and in this embodiment, the preferred thickness of the low-density graphite layer 1 is 50µm. A plurality of convex structures 4 are provided on the side of the low-density graphite layer 1 away from the double-sided adhesive layer 2. Preferably, the plurality of convex structures 4 are arranged in a wave shape. The convex structures 4 are formed by calendering the surface of the low-density graphite layer 1 with a concave-convex wave-shaped calendering roller. The wave-shaped structure is beneficial for a larger area of ​​material surface to participate in the multiple reflection attenuation of electromagnetic waves. The height of the convex structure 4 is 1-10µm. It should be noted that the height here refers to the vertical height between the highest point and the lowest point of the convex structure 4 with the horizontal direction of the low-density graphite layer 1 as the reference. Preferably, the height of the graphic structure in this embodiment can be 1µm, 2µm, 3µm, 4µm, 5µm, 6µm, 7µm, 8µm, 9µm or 10µm. In this embodiment, the preferred height of the convex structure 4 is 2µm. The double-sided adhesive layer 2 contains several conductive particles. Specifically, the double-sided adhesive layer 2 is an acrylic double-sided adhesive containing nickel powder. The thickness of the double-sided adhesive layer 2 is 3-30µm. Preferably, the thickness of the double-sided adhesive layer 2 can be 3µm, 5µm, 7µm, 10µm, 12µm, 15µm, 20µm, 22µm, 25µm, or 30µm. In this embodiment, the preferred thickness of the double-sided adhesive layer 2 is 5µm. In this embodiment, the high-density graphite layer 3 is a single layer. The high-density graphite layer 3 is obtained by intercalation and densification calendering of a graphite layer. The true density of the high-density graphite layer 3 is greater than 2.0 g / cm³. 3The thickness of the high-density graphite layer 3 is 17-150µm. Preferably, the thickness of the high-density graphite layer 3 can be 17µm, 20µm, 25µm, 30µm, 35µm, 40µm, 50µm, 60µm, 70µm, 80µm, 90µm, 100µm, 110µm, 120µm, 130µm, 140µm, 150µm, 160µm, or 170µm. In this embodiment, the preferred thickness of the high-density graphite layer 3 is 30µm. It should be noted that the specific preparation processes of the high-density graphite layer 3 and the low-density graphite layer 1 in this application can be obtained by those skilled in the art through existing technology; therefore, they will not be described in detail in this embodiment.

[0041] The implementation principle of Example 1 is as follows: Double-sided adhesive layer 2 is bonded to the surface of high-density graphite layer 3, and then low-density graphite layer 1 is bonded to the side of the double-sided adhesive layer away from the high-density graphite layer 3. A convex structure 4 is then formed on the surface of the low-density graphite layer 1 through calendering, thereby obtaining the electromagnetic shielding composite film of this embodiment. Through the combination of high-density graphite layer 3 and low-density graphite layer 1, it can both reflect and shield external electromagnetic waves and prevent internal electromagnetic waves from interfering with other electronic components. It has good flexibility, anti-electromagnetic interference performance, and heat dissipation performance, and good bonding stability to electronic components. It is suitable for assembling electronic components with irregular shapes or protruding structures. Example 2

[0042] The difference between Example 2 and Example 1 is that, based on Example 1, reference is made to... Figure 2 An adhesive layer 5 is provided on the side of the high-density graphite layer 3 away from the double-sided adhesive layer 2. The adhesive layer 5 is preferably an acrylic adhesive, and the thickness of the adhesive layer 5 is 2-10µm. Preferably, the thickness of the adhesive layer 5 can be 2µm, 3µm, 4µm, 4µm, 6µm, 7µm, 8µm, 9µm or 10µm. In this embodiment, the preferred thickness of the adhesive layer 5 is 2µm, and the other properties are the same as in Embodiment 1.

[0043] The implementation principle of Example 2 is as follows: the adhesive layer 5 enables the electromagnetic shielding composite film to be directly bonded and fixed to electronic components, which improves the convenience and stability in practical applications. Example 3

[0044] The difference between Example 3 and Example 2 is that, based on Example 2, reference is made to... Figure 3 In this embodiment, the high-density graphite layer 3 is set as two layers, and the two high-density graphite layers 3 are bonded together by an adhesive layer 5. An adhesive layer 5 is also provided on the side of the outermost high-density graphite layer 3 away from the double-sided adhesive layer 2. In this embodiment, the thickness of the low-density graphite layer 1 is 50µm, the thickness of the high-density graphite layer 3 is 20µm, and the rest is the same as in embodiment 2.

[0045] The implementation principle of Example 3 is as follows: by setting an adhesive layer 5 on the side of the high-density graphite layer 3 away from the double-sided adhesive layer 2, and setting two layers of high-density graphite layer 3, the adhesive layer 5 can bond the two layers of high-density graphite layer 3 together, which can further improve the electromagnetic shielding performance and flexibility of the electromagnetic shielding composite film. Example 4

[0046] The difference between Example 4 and Example 2 is that, based on Example 2, referring to... Figure 4 At least one side of the high-density graphite layer 3 is provided with a first copper plating layer 6. Specifically, there are three ways to provide the first copper plating layer 6: First, the first copper plating layer 6 is provided on the side of the high-density graphite layer 3 near the double-sided adhesive layer 2; second, the first copper plating layer 6 is provided on the side of the high-density graphite layer 3 near the adhesive layer 5; third, the first copper plating layer 6 is provided on both sides of the high-density graphite layer 3. In this embodiment, the third method is preferred. The first copper plating layer 6 is attached to the surface of the high-density graphite layer 3 by PVD copper plating. The thickness of the first copper plating layer 6 is 0.1-5µm. Preferably, the thickness of the first copper plating layer 6 can be 0.1µm, 0.5µm, 1µm, 1.2µm, 1.5µm, 2µm, 2.5µm, 3µm, 3.5µm, 4µm, 4.5µm, or 5µm. In this embodiment, the preferred thickness of the first copper plating layer 6 is 0.5µm.

[0047] The implementation principle of Example 4 is as follows: By setting a first copper plating layer 6 on the surface of the high-density graphite layer 3, the bonding stability between the double-sided adhesive layer 2 and the adhesive layer 5 and the high-density graphite layer 3 can be improved. The electromagnetic shielding composite film is used in the coating of electronic components with bending angles or protrusion structures, and it is not easy to have problems such as delamination and bubbles. At the same time, it can improve the conductivity and anti-electromagnetic interference performance of the electromagnetic shielding composite film. Example 5

[0048] The difference between Example 5 and Example 4 is that, based on Example 4, referring to... Figure 5 A second copper plating layer 7 is provided on one side of the low-density graphite layer 1 near the double-sided adhesive layer 2. The second copper plating layer 7 is attached to the surface of the low-density graphite layer 1 by PVD copper plating. The thickness of the second copper plating layer 7 is 0.1-5µm. Preferably, the thickness of the second copper plating layer 7 can be 0.1µm, 0.5µm, 1µm, 1.2µm, 1.5µm, 2µm, 2.5µm, 3µm, 3.5µm, 4µm, 4.5µm or 5µm. In this embodiment, the preferred thickness of the second copper plating layer 7 is 0.5µm.

[0049] The implementation principle of Example 5 is as follows: by setting a second copper plating layer 7 between the low-density graphite layer 1 and the double-sided adhesive layer 2, the bonding stability between the double-sided adhesive layer 2 and the low-density graphite layer 1 can be improved, further enhancing the bonding stability of the electromagnetic shielding composite film in the wrapping of electronic components with bending angles or protrusion structures, making it less prone to problems such as delamination and bubbles, and further improving the conductivity and anti-electromagnetic interference performance of the electromagnetic shielding composite film.

[0050] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An electromagnetic shielding composite film, characterized by: It includes a low-density graphite layer (1) and at least one high-density graphite layer (3), the low-density graphite layer (1) and the high-density graphite layer (3) are bonded together by a double-sided adhesive layer (2), the low-density graphite layer (1) is provided with a plurality of expansion holes (11), and the side of the low-density graphite layer (1) away from the double-sided adhesive layer (2) is provided with a plurality of convex structures (4).

2. The electromagnetic shielding composite film according to claim 1, characterized in that: An adhesive layer (5) is provided on the side of the high-density graphite layer (3) away from the double-sided adhesive layer (2).

3. The electromagnetic shielding composite film according to claim 2, wherein: The high-density graphite layer (3) is configured as two layers, and the two high-density graphite layers (3) are bonded together by the adhesive layer (5).

4. An electromagnetic shielding composite film according to any one of claims 1-3, characterized in that: At least one side of the high-density graphite layer (3) is provided with a first copper plating layer (6).

5. The electromagnetic shielding composite film according to claim 4, wherein: The low-density graphite layer (1) has a second copper plating layer (7) on one side near the double-sided adhesive layer (2).

6. The electromagnetic shielding composite film according to claim 5, wherein: The thickness of the first copper plating layer (6) and the second copper plating layer (7) is 0.1-5µm.

7. The electromagnetic shielding composite film according to claim 1, wherein: Several of the convex structures (4) are arranged in a wave shape, and the height of the convex structure (4) is 1-10µm.

8. The electromagnetic shielding composite film according to claim 1, wherein: The thickness of the low-density graphite layer (1) is 30-500µm.

9. The electromagnetic shielding composite film according to claim 1, wherein: The double-sided adhesive layer (2) contains a number of conductive particles, and the thickness of the double-sided adhesive layer (2) is 3-30µm.

10. The electromagnetic shielding composite film according to claim 1, wherein: The thickness of the high-density graphite layer (3) is 17-150µm.

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