A fire-resistant electromagnetic shielding composite material and its preparation method

Abstract

This invention provides a fire-resistant electromagnetic shielding composite material and its preparation method. The method includes: Step S1: preparing a surface layer of high-temperature resistant prepreg and an inner layer of prepreg; Step S2: laying out a preform in the following order: several layers of surface layer high-temperature resistant prepreg, several layers of inner layer prepreg, several layers of metal mesh, several layers of inner layer prepreg, and several layers of surface layer high-temperature resistant prepreg; Step S3: hot-pressing the preform to prepare a fire-resistant electromagnetic shielding composite material. This invention is a multi-functional composite material with a multi-layer, multi-type structural design. It not only possesses high specific strength and specific modulus mechanical properties, but also better fire resistance and electromagnetic shielding characteristics. It simultaneously meets the protection requirements under electromagnetic and high-temperature environments. Furthermore, the surface layer material has low thermal conductivity, high thermal stability, and ablation resistance, effectively protecting the integrity of the internal composite material and maximizing the protection of the overall structure and mechanical properties of the composite material.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, and more specifically, to a fire-resistant electromagnetic shielding composite material and its preparation method. Background Technology

[0002] During flight, numerous onboard avionics devices are powered on, tested, or operated within the confined space of the aircraft. The resulting electromagnetic waves can severely impact the reliability and accuracy of these electronic devices. Therefore, electronic modules must not only overcome external electromagnetic interference but also function normally within this confined space, providing crucial support for the aircraft's normal flight. Consequently, in existing technologies, each mechanical and electronic equipment module in the aviation field has specific shielding performance requirements to ensure the proper functioning of the subsystems and equipment they comprise and to meet the overall electromagnetic compatibility requirements of the aircraft.

[0003] Electromagnetic shielding technology utilizes the electrical and magnetic properties of the shielding material to prevent or reduce the transmission of electromagnetic energy, making it an effective method for suppressing radiation interference. Furthermore, in the aerospace field, to reduce weight, some fire-resistant and high-temperature-resistant materials also utilize resin-based composites, placing high demands on their fire resistance. Traditional epoxy resins decompose at 300℃ and have low residual carbon content, resulting in a loss of mechanical strength in the composite material, making it difficult to meet the aerospace field's requirements for high-temperature-resistant and fire-resistant composite materials. The demand for high-temperature-resistant and fire-resistant electromagnetic shielding composite materials for aerospace applications is even more significant; improving the fire resistance and electromagnetic shielding effectiveness of aerospace composite materials is a key technology directly related to the normal and safe operation of avionics equipment.

[0004] Chinese Patent 202020577103.5 discloses a fireproof structure for an automotive composite battery box. It adopts a structural design with fireproof layers on the inner and outer sides and a composite material layer in the middle. The battery box body is formed into an integral structure through molding or liquid molding processes. The fireproof layer is designed on the inner and outer surfaces of the battery box, which improves the fireproof effect. The structure proposed in this patent has fireproof performance, but does not have electromagnetic shielding effectiveness.

[0005] Chinese Patent 202210054834.5 discloses an electromagnetic shielding anti-penetration material, its preparation method and application, which can reduce the surface density and thickness of the protective structure and has certain electromagnetic shielding performance, and can limit the penetration damage to a small area. The structure proposed in this patent has electromagnetic shielding and anti-penetration performance, but does not involve fireproof function. Summary of the Invention

[0006] The problem solved by this invention is that, in the prior art, the electromagnetic shielding or fire resistance of composite materials used in aviation is poor, and cannot simultaneously meet the requirements for electromagnetic shielding and fire resistance.

[0007] This invention discloses a method for preparing a fire-resistant electromagnetic shielding composite material, comprising the following steps:

[0008] Includes the following steps:

[0009] Step S1: Prepare the surface high-temperature resistant prepreg and the inner prepreg;

[0010] Step S2: Lay out layers of high-temperature resistant prepreg, layers of inner prepreg, layers of metal mesh, layers of inner prepreg, and layers of high-temperature resistant prepreg in sequence to form a precast body.

[0011] Step S3: Hot-press the preform to prepare a fire-resistant electromagnetic shielding composite material.

[0012] The surface layer high-temperature resistant prepreg is an ablation-resistant high-temperature composite material used to form the thermal protection layer of the fire-resistant electromagnetic shielding composite material, giving it thermal conductivity, high thermal stability, and ablation resistance, significantly improving the fire resistance of the finished fire-resistant electromagnetic shielding composite material. Simultaneously, the laying of a metal mesh gives the fire-resistant electromagnetic shielding composite material good electromagnetic shielding effectiveness, thus enabling the finished composite material to possess both electromagnetic shielding and good fire resistance. Furthermore, the inner layer prepreg has good specific strength and specific modulus, meeting the requirements of the aerospace industry. Through the above configuration, the finished composite material exhibits good high-temperature and ablation resistance, high structural strength, and excellent electromagnetic shielding performance, effectively meeting the functional requirements of composite materials in harsh environments (high temperature, dense electromagnetic fields). Further, step S1 includes:

[0013] Step S11: Heat the solid benzoxazine resin until it is in a molten or flowing state;

[0014] Step S12: The molten benzoxazine resin is uniformly brushed onto the high-silica fiber cloth to form a surface high-temperature resistant prepreg; the molten benzoxazine resin is uniformly brushed onto the carbon fiber cloth to form an inner prepreg.

[0015] The high-temperature resistant prepreg formed by combining benzoxazine resin and high-silica fiber cloth has advantages such as low shrinkage, low water absorption, and high residual carbon content after ablation. Using it as the surface layer material can effectively protect the inner structure, thus preventing its internal structure from being affected during ablation. The inner prepreg formed by combining benzoxazine resin and carbon fiber cloth is lightweight and has high structural strength. Combining it with the high-temperature resistant prepreg in the surface layer results in a finished material that possesses the advantages of both. Simultaneously, the inner prepreg effectively protects the internal metal mesh, ensuring stable electromagnetic shielding performance of the finished composite material. Through the above arrangement, a certain thickness of high-silica / benzoxazine resin composite material is formed on the surface of the fire-resistant electromagnetic shielding composite material, significantly improving the fire resistance of the finished composite material. Combined with the internal metal mesh 3, this gives the finished composite material excellent electromagnetic shielding performance.

[0016] Furthermore, the heating temperature in step S11 is between 30°C and 150°C.

[0017] Within this temperature range, solid benzoxazine resin can be transformed into a molten or fluid state without making the viscosity too low, which can effectively ensure the smooth preparation of the surface high-temperature resistant prepreg and the inner prepreg.

[0018] Furthermore, in step S11, the viscosity of the benzoxazine resin in a molten or flowing state is between 5000 and 30000 mPa·s.

[0019] When benzoxazine resin is in a molten or flowing state within this viscosity range, it can effectively ensure the smooth preparation of the surface high-temperature resistant prepreg and the inner prepreg.

[0020] Furthermore, in the surface high-temperature resistant prepreg and / or inner prepreg prepared in step S12, the mass percentage of benzoxazine resin is 20-80%.

[0021] When the mass percentage of benzoxazine resin in the prepreg is within the above range, the total weight, fire resistance, and electromagnetic shielding performance of the finished composite material are within a relatively good range.

[0022] Furthermore, in step S12, the density of the high-silica fiber cloth is 100 g / m³. 2 ~400g / m 2 The density of the carbon fiber cloth is 100 g / m³. 2 ~500g / m 2 .

[0023] Furthermore, the metal mesh is one or more of copper mesh, iron mesh, and nickel mesh.

[0024] Composite materials prepared using the metal mesh described above can possess excellent electromagnetic shielding capabilities.

[0025] Furthermore, the mesh count of the metal mesh is between 100 and 800.

[0026] Furthermore, in step S3, the thickness ratios of the surface high-temperature resistant prepreg, inner prepreg, and metal mesh in the electromagnetic shielding composite material are as follows: surface high-temperature resistant prepreg is 25%–40%, inner prepreg is 50%–70%, and metal mesh is 5%–10%.

[0027] The above configuration maximizes the thickness and volume ratio of the inner prepreg, thereby effectively reducing the weight of the finished composite material while ensuring its excellent fire resistance and electromagnetic shielding performance. This results in a final composite material with high specific strength and specific modulus, good shock absorption, and high fatigue resistance, meeting the protection requirements in complex environments. It can be widely used in the aerospace field for high temperature resistance, fire resistance, and electromagnetic interference resistance.

[0028] The present invention also discloses a fire-resistant electromagnetic shielding composite material, which is produced by the preparation method described above.

[0029] The fire-resistant electromagnetic shielding composite material has the same advantages over the prior art as the preparation method described above, and will not be repeated here.

[0030] Compared with existing technologies, the fire-resistant electromagnetic shielding composite material and its preparation method described in this invention have the following advantages:

[0031] 1) The resin system used in this invention has advantages such as low volume shrinkage, low water absorption, and high residual carbon rate after ablation, which meets the high precision requirements and fire resistance of the product during use.

[0032] 2) This invention uses a high-silica / benzoxazine composite material as the thermal protection layer of a multifunctional structural composite material. The surface material has low thermal conductivity, high thermal stability and ablation resistance; it can effectively protect the integrity of the internal composite material and maximize the protection of the overall structure and mechanical properties of the composite material.

[0033] 3) This invention is a multifunctional composite material with a multi-layered, multi-type structural design, allowing different materials to fully utilize their properties. It not only possesses the high specific strength and specific modulus of composite materials, but also exhibits better fire resistance and electromagnetic shielding characteristics. It simultaneously meets protection requirements under electromagnetic and high-temperature environments, with a shielding effectiveness of not less than 30dB in the 1MHz–900MHz range, and the structure remains intact after 5 minutes of flame ablation at 1200℃. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic cross-sectional view of the fire-resistant electromagnetic shielding composite material described in an embodiment of the present invention.

[0036] Figure 2 This is a schematic diagram of the production steps of the fire-resistant electromagnetic shielding composite material according to an embodiment of the present invention.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. First high-silica fiber prepreg; 2. First carbon fiber prepreg; 3. Metal mesh; 4. Second carbon fiber prepreg; 5. Second high-silica fiber prepreg; 6. Mold. Detailed Implementation

[0039] To make the technical means and objectives and effects of the present invention easier to understand, the embodiments of the present invention will be described in detail below with reference to specific illustrations.

[0040] It should be noted that all directional and positional terms used in this invention, such as "up," "down," "left," "right," "front," "back," "vertical," "horizontal," "inner," "outer," "top," "lower," "lateral," "longitudinal," and "center," are only used to explain the relative positional relationships and connections between components in a specific state (as shown in the accompanying drawings). They are merely for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. Furthermore, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0041] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0042] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0043] With the rapid development of aerospace technology, the demand for lightweight materials is constantly increasing, leading to a growing reliance on advanced composite materials with high specific strength, low density, high stiffness, high temperature and fire resistance, and electromagnetic shielding properties. Resin-based composite materials typically exhibit good specific strength and modulus, fatigue resistance, and corrosion resistance. If resin-based composite materials also possess high temperature and fire resistance and electromagnetic shielding capabilities, it would solve two major problems in the application of composite materials in the aerospace field.

[0044] The purpose of electromagnetic shielding technology is to prevent the propagation of electromagnetic waves. Whether it is a metal shielding material or a conductive polymer composite material, it is achieved by adding highly conductive fillers to the material to reflect the incident electromagnetic waves.

[0045] The following describes in detail, with reference to the accompanying drawings, an embodiment of the present invention: a fire-resistant electromagnetic shielding composite material and its preparation method.

[0046] Example 1

[0047] This embodiment provides a method for preparing a fire-resistant electromagnetic shielding composite material, including the following steps:

[0048] Step S1: Prepare the surface high-temperature resistant prepreg and the inner prepreg;

[0049] Step S2: Lay out layers of high-temperature resistant prepreg, layers of inner prepreg, layers of metal mesh, layers of inner prepreg, and layers of high-temperature resistant prepreg in sequence to form a precast body.

[0050] Step S3: Hot-press the preform to prepare a fire-resistant electromagnetic shielding composite material.

[0051] The surface high-temperature resistant prepreg is an ablation-resistant high-temperature composite material used to form the thermal protection layer of the fire-resistant electromagnetic shielding composite material. This gives it thermal conductivity, high thermal stability, and ablation resistance, significantly improving the fire resistance of the finished fire-resistant electromagnetic shielding composite material. Simultaneously, the metal mesh provides excellent electromagnetic shielding effectiveness, resulting in a composite material that combines electromagnetic shielding and good fire resistance. Furthermore, the inner prepreg has good specific strength and specific modulus, meeting the requirements of the aerospace industry. Through these features, the finished composite material exhibits good high-temperature and ablation resistance, high structural strength, and excellent electromagnetic shielding performance, effectively meeting the functional requirements of the composite material in harsh environments (high temperature, dense electromagnetic fields). In some optional embodiments, the surface high-temperature resistant prepreg is a benzoxazine resin / high-silica prepreg, and the inner prepreg is a benzoxazine resin / carbon fiber prepreg. In step S3, hot pressing can be performed using typical molding processes such as compression molding, autoclave molding, and vacuum bag molding. The preform after layup is heated and pressurized to cure, thus preparing a composite material that integrates high temperature resistance and electromagnetic shielding structure.

[0052] Step S1 includes:

[0053] Step S11: Heat the solid benzoxazine resin until it is in a molten or flowing state;

[0054] Step S12: The molten benzoxazine resin is uniformly brushed onto the high-silica fiber cloth to form a surface high-temperature resistant prepreg; the molten benzoxazine resin is uniformly brushed onto the carbon fiber cloth to form an inner prepreg.

[0055] The high-temperature resistant prepreg formed by combining benzoxazine resin and high-silica fiber cloth has advantages such as low shrinkage, low water absorption, and high residual carbon content after ablation. Using it as the surface layer material can effectively protect the inner structure, thus preventing its internal structure from being affected during ablation. The inner prepreg formed by combining benzoxazine resin and carbon fiber cloth is lightweight and has high structural strength. Combining it with the high-temperature resistant prepreg in the surface layer results in a finished material that possesses the advantages of both. Simultaneously, the inner prepreg effectively protects the internal metal mesh, ensuring stable electromagnetic shielding performance of the finished composite material. Through the above arrangement, a certain thickness of high-silica / benzoxazine resin composite material is formed on the surface of the fire-resistant electromagnetic shielding composite material, significantly improving the fire resistance of the finished composite material. Combined with the internal metal mesh 3, this gives the finished composite material excellent electromagnetic shielding performance. Based on this, the laying sequence corresponding to step S2 is as follows: several layers of first high-silica fiber prepreg 1, several layers of first carbon fiber prepreg 2, metal mesh 3, several layers of second carbon fiber prepreg 4, and several layers of second high-silica fiber prepreg 5. This laying process forms a multi-layer composite material with a metal mesh 3, resulting in a finished composite material that possesses fire resistance, electromagnetic shielding, and high structural strength. Specifically, the first high-silica fiber prepreg 1 and the second high-silica fiber prepreg 5 are both surface-layer high-temperature resistant prepregs formed in step S12, and the first carbon fiber prepreg 2 and the second carbon fiber prepreg 4 are both inner-layer prepregs formed in step S12. The first high-silica fiber prepreg 1 and the second high-silica fiber prepreg 5 are essentially the same, and the first carbon fiber prepreg 2 and the second carbon fiber prepreg 4 are essentially the same; the designation "first" and "second" is merely for ease of differentiation in their laying sequence. Optionally, in step S11, the solid benzoxazine resin can be heated using an electric heating box or oven, or other equipment capable of stable heating. It should be noted that before laying in step S2, molten or flowing benzoxazine resin can be uniformly coated on the metal mesh to avoid air from appearing inside the composite material and ensure the compactness of the material.

[0056] As an optional example, the heating temperature in step S11 is between 30°C and 150°C.

[0057] Within this temperature range, solid benzoxazine resin can be transformed into a molten or fluid state without making the viscosity too low, which can effectively ensure the smooth preparation of the surface high-temperature resistant prepreg and the inner prepreg.

[0058] As an example of the present invention, in step S11, the viscosity of the benzoxazine resin in a molten or flowing state is 5000 to 30000 mPa·s.

[0059] When benzoxazine resin is in a molten or flowing state within this viscosity range, it can effectively ensure the smooth preparation of the surface high-temperature resistant prepreg and the inner prepreg.

[0060] In this example, the benzoxazine resin accounts for 20-80% of the mass of the surface high-temperature resistant prepreg and / or inner prepreg prepared in step S12.

[0061] When the mass percentage of benzoxazine resin in the prepreg is within the above range, the total weight, fire resistance, and electromagnetic shielding performance of the finished composite material are within a relatively good range.

[0062] As an example of the present invention, in step S12, the density of the high-silica fiber cloth is 100 g / m³. 2 ~400g / m 2 The density of the carbon fiber cloth is 100 g / m³. 2 ~500g / m 2 .

[0063] As an example of the present invention, the mesh count of the metal mesh is between 100 and 800.

[0064] Specifically, the metal mesh is one or more of copper mesh, iron mesh, and nickel mesh.

[0065] Composite materials prepared using the metal mesh described above can possess excellent electromagnetic shielding capabilities.

[0066] In step S3, the thickness ratios of the surface high-temperature resistant prepreg, inner prepreg, and metal mesh in the electromagnetic shielding composite material are as follows: surface high-temperature resistant prepreg 25%–40%, inner prepreg 50%–70%, and metal mesh 5%–10%.

[0067] The above configuration maximizes the thickness and volume ratio of the inner prepreg, thereby effectively reducing the weight of the finished composite material while ensuring its excellent fire resistance and electromagnetic shielding performance. This results in a final composite material with high specific strength and specific modulus, good shock absorption, and high fatigue resistance, meeting the protection requirements in complex environments. It can be widely used in the aerospace field for high temperature resistance, fire resistance, and electromagnetic interference resistance.

[0068] Example 2

[0069] This embodiment provides a fire-resistant electromagnetic shielding composite material, which is prepared using the preparation method described in Example 1.

[0070] The requirements for the fire-resistant electromagnetic shielding composite material are as follows:

[0071] The enclosure should be designed to have good fire resistance and electromagnetic shielding performance, with a thickness of 4mm. The enclosure should have a shielding effectiveness of more than 30dB in the range of 1MHz to 900MHz and should remain structurally intact after being subjected to flame erosion at 1200℃ for 5 minutes.

[0072] Its preparation method is as follows:

[0073] Solid benzoxazine resin was placed in a heating chamber and heated to 60°C with a vacuum. The heating time was set to 40 minutes. After heating, 50% (percentage of the total weight of resin and fiber cloth) of the resin was weighed and evenly coated onto the surfaces of high-silica fiber, carbon fiber, and metal mesh to prepare the prepreg. The prepreg was orthogonally laid on the mold 6 in the following structural order: first high-silica fiber prepreg 1 / first carbon fiber prepreg 2 / metal mesh 3 / second carbon fiber prepreg 4 / second high-silica fiber prepreg 5. A total of 12 layers were laid, including 2 layers of first high-silica fiber prepreg 1, 3 layers of first carbon fiber prepreg 2, 2 layers of metal mesh 3, 3 layers of second carbon fiber prepreg 4, and 2 layers of second high-silica fiber prepreg 5. The mold is closed and the temperature is gradually increased by pressing. When the temperature reaches 90℃, the pressure is held for 1 hour. Then the pressure is increased by pressing each piece. When the temperature reaches 120℃ and the pressure reaches 4MPa, the pressure is held for 2 hours. When the temperature rises to 250℃, the pressure is held for 2 hours. Then the temperature is allowed to cool naturally. When the temperature is below 70℃, the piece is demolded.

[0074] Example 3

[0075] This embodiment provides a fire-resistant electromagnetic shielding composite material, which is prepared using the preparation method described in Example 1.

[0076] The requirements for the fire-resistant electromagnetic shielding composite material are as follows:

[0077] The enclosure should be designed to have good fire resistance and electromagnetic shielding performance, with a thickness of 4mm. The enclosure should have a shielding effectiveness of more than 30dB in the range of 1MHz to 900MHz and should remain structurally intact after being subjected to flame erosion at 1200℃ for 5 minutes.

[0078] Its preparation method is as follows:

[0079] Solid benzoxazine resin was placed in a heating chamber and heated to 150°C with a vacuum. The heating time was set to 20 minutes. After heating, 70% (percentage of the total weight of resin and fiber cloth) of the resin was weighed and evenly coated onto the surfaces of high-silica fiber, carbon fiber, and metal mesh to prepare the prepreg. The prepreg was orthogonally laid on the mold 6 in the following structural order: first high-silica fiber prepreg 1 / first carbon fiber prepreg 2 / metal mesh 3 / second carbon fiber prepreg 4 / second high-silica fiber prepreg 5. A total of 12 layers were laid, including 3 layers of first high-silica fiber prepreg 1, 2 layers of first carbon fiber prepreg 2, 2 layers of metal mesh 3, 2 layers of second carbon fiber prepreg 4, and 3 layers of second high-silica fiber prepreg 5. The mold is closed and the temperature is gradually increased by pressing. When the temperature reaches 120℃, the pressure is held for 40 minutes. Then the pressure is increased by pressing each piece. When the temperature reaches 180℃ and the pressure reaches 4MPa, the pressure is held for 2 hours. When the temperature rises to 250℃, the pressure is held for 2 hours. Then the temperature is allowed to cool naturally. When the temperature is below 50℃, the piece is demolded.

[0080] It should be noted that the thickness ratio of the surface high-temperature resistant prepreg, the inner prepreg, and the metal mesh in Example 3 is not within the range limited by the example. Compared with Comparative Document 1 and Comparative Document 2, its fire resistance is improved, but its structural strength is reduced. It can be used in different application environments.

[0081] The fire-resistant electromagnetic shielding composite material prepared by the above method has an outer layer made of high-silica material and an inner structural layer of high-strength, high-modulus carbon fiber composite material and multi-layer metal mesh. It not only exhibits excellent high-temperature resistance and fire resistance, and superior shielding effect, but also possesses high specific strength and high specific modulus, good shock absorption performance, and high fatigue resistance. This composite material can be used as a protective shell or enclosure for electronic devices or avionics equipment in high-temperature environments in aerospace equipment, effectively meeting the functional requirements of composite materials in harsh environments (high temperature, dense electromagnetic fields).

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a fire-resistant electromagnetic shielding composite material, characterized in that, Includes the following steps: Step S1: Prepare the surface high-temperature resistant prepreg and the inner prepreg; Step S2: Lay out layers of high-temperature resistant prepreg, layers of inner prepreg, layers of metal mesh, layers of inner prepreg, and layers of high-temperature resistant prepreg in sequence to form a precast body. Step S3: Hot-press the preform to prepare a fire-resistant electromagnetic shielding composite material; Step S1 includes: Step S11: Heat the solid benzoxazine resin until it is in a molten or flowing state; Step S12: The molten benzoxazine resin is uniformly brushed onto the high-silica fiber cloth to form the surface high-temperature resistant prepreg; the molten benzoxazine resin is uniformly brushed onto the carbon fiber cloth to form the inner prepreg. Before step S2, molten or flowing benzoxazine resin is uniformly coated onto the metal mesh.

2. The method for preparing the fire-resistant electromagnetic shielding composite material as described in claim 1, characterized in that, The heating temperature in step S11 is between 30°C and 150°C.

3. The method for preparing the fire-resistant electromagnetic shielding composite material as described in claim 1, characterized in that, In step S11, the viscosity of the benzoxazine resin in a molten or flowing state is 5000–30000 mPa·s.

4. The method for preparing the fire-resistant electromagnetic shielding composite material as described in claim 1, characterized in that, In the surface high-temperature resistant prepreg and / or inner prepreg prepared in step S12, the mass ratio of benzoxazine resin is 20-80%.

5. The method for preparing the fire-resistant electromagnetic shielding composite material as described in claim 1, characterized in that, In step S12, the density of the high-silica fiber cloth is 100 g / m³. 2 ~400g / m 2 The density of the carbon fiber cloth is 100 g / m³. 2 ~500g / m 2 .

6. The method for preparing the fire-resistant electromagnetic shielding composite material as described in claim 1, characterized in that, The metal mesh is one or more of copper mesh, iron mesh, and nickel mesh.

7. The method for preparing the fire-resistant electromagnetic shielding composite material as described in claim 1, characterized in that, The mesh count of the metal mesh is between 100 and 800.

8. The method for preparing the fire-resistant electromagnetic shielding composite material according to any one of claims 1-7, characterized in that, In step S3, the thickness ratios of the surface high-temperature resistant prepreg, inner prepreg, and metal mesh in the electromagnetic shielding composite material are as follows: surface high-temperature resistant prepreg 25%–40%, inner prepreg 50%–70%, and metal mesh 5%–10%.

9. A fire-resistant electromagnetic shielding composite material, characterized in that, Produced using the preparation method described in any one of claims 1-8.

Images