A broadband electromagnetic shielding rubber material and a preparation method and application thereof

Abstract

The application belongs to the technical field of new materials, and specifically provides a wide-band electromagnetic shielding rubber material, a preparation method thereof and an application thereof. Raw materials include a rubber matrix, white carbon black, conductive fillers, a plasticizer, a coupling agent, an antioxidant, an ultraviolet absorber, a metal ion passivator and a vulcanizing agent. In particular, the conductive fillers are compounded from silver powder, silver-plated aluminum powder and nickel-plated carbon powder, and the thiol-containing silane coupling agent is used in combination, so that the water vapor invading the material interior in the use process can cause the coupling agent corrosion-inhibiting layer to hydrolyze and crosslink, a crosslinked siloxane network is formed, and the corrosion-inhibiting layer is more dense. Not only can the salt mist aging resistance be improved, but also the compatibility and bonding force with the rubber matrix are enhanced, and the conductivity of the matrix is improved. The overall aging resistance of the material is improved by using a composite anti-aging system, thereby meeting the working condition use requirements of the wide-band, aging-resistant electromagnetic shielding rubber material for electronic shelters.

Description

Technical Field

[0001] This invention belongs to the field of new materials, and specifically relates to a broadband electromagnetic shielding rubber material, its preparation method, and its application. Background Technology

[0002] Modular shelters, with their excellent airtight protection and high mobility, have been widely used in command systems, electronic warfare systems, and other fields. However, electromagnetic waves emitted by high-power microwave weapons and electromagnetic pulse weapons can enter these systems through gaps and holes, damaging the electronic and electrical components inside the shelter and directly affecting the performance of information-based weaponry. The hatch, being the largest opening in the shelter, is a significant pathway for electromagnetic wave leakage; its sealing and shielding performance is crucial to the overall shielding effectiveness of the shelter.

[0003] Currently, the outer shielding structure of domestic modular shelter doors generally uses shielding wire mesh gaskets. These wire meshes are woven from metal wires, and due to the presence of gaps on their surface, they are difficult to provide an effective environmental seal. Especially in high-salt-spray, humid, and hot environments, they are highly susceptible to corrosion of internal components. Furthermore, metal wires lack elasticity and are prone to irreversible deformation during use, creating electromagnetic leakage points and failing to meet the requirements for efficient electromagnetic protection across a wide frequency range.

[0004] Electromagnetic shielding rubber is a type of composite rubber material that combines elastic sealing and conductivity. It is prepared by incorporating conductive powder into a rubber matrix through mixing and vulcanization processes. Its core advantage lies in its ability to achieve both dustproof sealing between equipment components and electromagnetic interference shielding, making it widely used in sealed conductive components of electronic, aerospace, and electronic communication equipment. However, traditional electromagnetic shielding rubber materials only achieve electromagnetic shielding effectiveness of around 60 dB or even lower in a wide frequency range (30 MHz-40 GHz), while new electronic shelters place higher demands on electromagnetic shielding seals (≥85 dB). Electromagnetic shielding materials with good performance in the 30 MHz-40 GHz wide frequency range should have high electrical conductivity and magnetic permeability. The lower the resistance of the shielding material, the larger the eddy current generated, the stronger the countermagnetic field, and the better the shielding effect at high frequencies. Materials with high magnetic permeability are used for shielding low-frequency magnetic fields; the higher the relative magnetic permeability, the better the shielding effect.

[0005] Meanwhile, new electronic modular equipment requires all-terrain operational capabilities and places certain demands on the lifespan of electromagnetic shielding seals. Traditional electromagnetic shielding rubber has poor aging resistance and is easily affected by the combined effects of external factors such as ozone, humidity, heat, and salt spray during use, gradually losing its functionality and leading to performance failure, posing a serious threat to the normal operation of electronic equipment and critical compartments. Currently, improving the aging resistance of electromagnetic shielding rubber mainly involves two approaches: firstly, improving the salt spray resistance of the conductive powder itself; and secondly, improving the anti-aging properties of the rubber formulation.

[0006] Patent CN112646377A discloses a conductive silicone rubber for electromagnetic shielding and its preparation method. Its key feature is the surface modification of the conductive filler and fumed silica by reacting them with a coupling agent, resulting in a significant increase in the amount of conductive filler used in the silicone rubber compound. This increased content of conductive filler enhances the electromagnetic shielding performance of the conductive silicone rubber, thus leading to a substantial increase in production costs.

[0007] Patent CN107936343A discloses an electromagnetic shielding rubber material, characterized by the addition of nickel-plated carbon nanotubes, silver-plated copper powder, and stainless steel powder as conductive materials to a rubber matrix, giving the material excellent electrical and thermal conductivity. However, due to the low volume resistivity of the added conductive fillers, the wide-band shielding effectiveness is poor, and the silver-plated copper powder is easily oxidized, resulting in insufficient material durability. Furthermore, electronic shelters require electromagnetic shielding seals with aging resistance and high wide-band electromagnetic shielding effectiveness; therefore, the aforementioned material is insufficient to meet the operational requirements of electronic shelters.

[0008] Patent CN107236161A discloses a high thermal conductivity electromagnetic shielding rubber and its preparation method. The matrix used is styrene-butadiene rubber (SBR), nitrile rubber (NBR), natural rubber (NR), and chloroprene rubber (CR). The upper limit of the conductive material added to this type of rubber is relatively low, basically around 50 phr. Therefore, the conductive fillers used are mainly conductive carbon black and large particle size (0.2-5mm) metal fillers, and the addition amount is small. The final material is only suitable for use in ultra-low frequency (10KHz~20MHz) environments, and it cannot meet the operating conditions requirements of electronic shelters.

[0009] Therefore, providing a broadband, aging-resistant electromagnetic shielding rubber material that is more suitable for use in our military's electronic container has become one of the key research focuses of the inventors. Summary of the Invention

[0010] To address the aforementioned problems, this invention provides a broadband electromagnetic shielding rubber material, its preparation method, and its application. The raw materials include a rubber matrix, silica, conductive filler, plasticizer, coupling agent, antioxidant, ultraviolet absorber, metal ion passivator, and vulcanizing agent. Specifically, it employs a conductive filler composed of silver powder, silver-plated aluminum powder, and nickel-plated carbon powder, along with a mercapto-containing silane coupling agent. During use, moisture penetrating the material causes hydrolysis and cross-linking of the coupling agent's corrosion-inhibiting layer, forming a cross-linked siloxane network, resulting in a denser corrosion-inhibiting layer. This not only improves salt spray aging resistance but also enhances compatibility and adhesion with the rubber matrix, improving the matrix's conductivity. The composite anti-aging system improves the overall aging resistance of the material, thus meeting the operational requirements of broadband, aging-resistant electromagnetic shielding rubber materials for electronic shelters.

[0011] The innovation of this invention lies in the compounding of three conductive fillers: silver powder, silver-plated aluminum powder, and nickel-plated carbon powder, with specified compounding ratios and addition amounts. Utilizing the attenuation effect of each conductive particle at different frequency bands, a high-efficiency electromagnetic shielding rubber material meeting the requirements for use across a wider frequency range (30MHz-40GHz) is obtained. Simultaneously, by selecting a superior coupling agent, leveraging the strong affinity between mercapto-based silane coupling agents and the silver layer, the coupling agent forms a corrosion-inhibiting layer on the surface of the conductive filler, acting as a "bridge" between the silver layer and the rubber, thereby improving the mechanical properties of the composite material. Furthermore, the denser corrosion-inhibiting layer significantly improves the material's salt spray resistance, effectively preventing corrosion and aging failure of the conductive filler, thus extending the material's service life. For the rubber formulation, a composite anti-aging system is preferentially adopted, combining antioxidants, ultraviolet absorbers, and metal ion passivators to synergistically resist combined aging caused by ozone, salt spray, and other factors.

[0012] Based on the above inventive concept, the specific technical solution of this application is as follows: A broadband electromagnetic shielding rubber material, the raw material composition by weight is as follows: 100 parts by weight of rubber matrix 15-40 parts by weight of silica 180-300 parts by weight of conductive filler 1-4 parts by weight of plasticizer 2-8 parts by weight of coupling agent Compound anti-aging system 1.8–4 parts by weight 1 to 3 parts by weight of vulcanizing agent.

[0013] The rubber matrix is ​​methyl vinyl silicone rubber, wherein the vinyl content in the methyl vinyl silicone rubber is 0.05-0.12%, and the specific alternative types are 110-2 or 110-3.

[0014] The particle size of the silica is controlled between 12 and 200 nm, and it can be one of HL-200, TS-530, HB-630, and RD-201. The conductive filler is a blend of silver powder, silver-plated aluminum powder, and nickel-plated carbon powder in a specific ratio of (20-40):(80-140):(80-120). Compared with existing technologies, the above-mentioned conductive filler combines highly conductive fillers such as pure silver powder, highly magnetic materials such as nickel-plated carbon powder, and silver-plated aluminum powder, which has both excellent electrical conductivity and a certain degree of magnetic permeability. The blending ratio of the three is strictly controlled. The larger-particle-size pure silver powder and nickel-plated carbon powder form the main framework, with the conductive powder particles in contact with each other, resulting in numerous micro-voids. The smaller-particle-size silver-plated aluminum powder fills the spaces between the larger-particle-size framework fillers, thus filling a significant portion of the voids. This reduces the voids between the conductive powder particles, lowering the contact resistance and forming a dense, continuous conductive network. The combined use of these three materials results in a material with high shielding effectiveness (≥85dB) in the low-frequency range of 30MHz to ultra-high-frequency range of 40GHz. Furthermore, the inventors verified the preparation of conductive rubber using only silver-plated aluminum powder and nickel-plated carbon powder. Electromagnetic shielding effectiveness tests revealed that neither of these conductive powders alone could achieve high shielding effectiveness across a wide frequency range. Pure silver powder is expensive, making the cost of preparing conductive rubber solely with pure silver powder prohibitively high. Therefore, the aforementioned specially formulated conductive filler was ultimately chosen.

[0015] More preferably, the pure silver powder has a silver content of ≥97% and a particle size of 80-120 μm; the silver content in the silver-plated aluminum powder is 10-30% and the particle size is 10-50 μm; the nickel content in the nickel-plated carbon powder is ≥60% and the particle size is 100-150 μm; and more preferably, the amount of conductive filler is 250-300 parts by weight.

[0016] The coupling agent is a mercapto-containing silane coupling agent, specifically one of KH590, A189, and KH-802. The above-mentioned mercapto-containing silane coupling agent has a strong affinity for the silver layer compared to other coupling agents, making it easier to form a corrosion-inhibiting layer on the surface of the conductive filler. It acts as a "bridge" between the silver layer and the rubber, thereby improving the mechanical properties of the composite material. On the other hand, the corrosion-inhibiting layer can significantly improve the salt spray resistance of the material, thereby increasing the service life of the material.

[0017] The plasticizer is a hydroxyl silicone oil, specifically one of OH-72, OH-82, OH-81, and JF-203; The compound anti-aging system consists of three components: antioxidant, ultraviolet absorber, and metal particle passivator, used in a weight ratio of (0.5-1):(0.3-1):(1-2). The antioxidant is a hindered phenolic antioxidant, specifically one of 1010 and 1790; the ultraviolet absorber is specifically one of UV-531, UV-327, and HALS; and the metal particle passivator is specifically one of PVP-K30, SY-88, and TEGO Protect 5000.

[0018] Among them, the hindered phenolic antioxidant can inhibit and prevent the conductive powder from being oxidized to form an insulating layer, thus avoiding the increase in volume resistivity and the decrease in electromagnetic shielding effectiveness from the root. At the same time, since the amount of conductive powder added in this invention is large, the metal filler will accelerate the aging of the rubber. The hindered phenolic antioxidant can stabilize the rubber matrix, so that the compound rubber has stable performance during long-term service. Ultraviolet absorbers can effectively protect the rubber matrix from aging and cracking due to ultraviolet rays, thus extending its service life; at the same time, they can prevent conductive fillers from undergoing oxidation reactions induced by ultraviolet rays, forming an oxide layer, and affecting the shielding effectiveness. Conductive powder metals can release trace amounts of metal ions, which act as a strong aging catalyst, causing rubber to soften rapidly, become sticky, and crack at high temperatures. Metal particle passivators can lock in the released metal ions, eliminating the aging catalyst. At the same time, metal particle passivators can prevent the accelerated oxidation of conductive ions, improving the stability of materials during long-term service.

[0019] The aforementioned metal particle passivator, ultraviolet absorber, and hindered phenolic antioxidant work synergistically to form a protective system, providing more comprehensive and efficient protection. The ultraviolet absorber is responsible for blocking external ultraviolet radiation, the antioxidant is responsible for internal oxidation prevention, and the metal particle passivator is responsible for stabilizing the conductive filler.

[0020] The vulcanizing agent is one of dicumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butyl peroxide), or di-(tert-butylperoxyisopropyl)phenylhexane.

[0021] All of the above-mentioned additives can be purchased directly from the market, and the inventor will not elaborate further.

[0022] In existing technologies, without proper protection, silver particles in the conductive filler of electromagnetic shielding rubber are directly exposed to heat, oxygen, and salt spray environments. Severe corrosion of the silver layer directly reduces the material's conductivity, thereby lowering its electromagnetic shielding performance. This application addresses this issue by utilizing the strong interaction between the thiol groups of the mercaptosilane coupling agent and silver. During use, moisture penetrating the material causes hydrolysis and cross-linking of the coupling agent corrosion inhibitor layer, forming a cross-linked siloxane network, making the corrosion inhibitor layer denser. Simultaneously, the silane coupling agent enhances the bonding force between the filler and the rubber matrix. By controlling the thickness of the silane coupling agent corrosion inhibitor layer, both the aging resistance of the electromagnetic shielding rubber and the overall shielding effectiveness of the compound are improved. Electromagnetic shielding rubber is usually processed using internal mixing and open milling. Due to the high shear strength of internal mixers and open mills, the conductive particles in the electromagnetic shielding rubber are severely damaged, which can easily cause the coating to peel off and seriously affect the conductivity of the compound. This application improves the mixing method and strictly controls the mixing time, effectively avoiding the damage of the conductive powder coating and ensuring the various properties of the electromagnetic shielding compound.

[0023] Therefore, the inventors further provided a method for preparing the aforementioned broadband electromagnetic shielding rubber material, the specific steps of which are as follows: (1) Mix the coupling agent and the dispersing solvent evenly to obtain a modified solution. The amount of the dispersing solvent is 50 to 100 times the mass of the coupling agent. The dispersing solvent used is acetone or anhydrous ethanol. (2) Stir and disperse the conductive filler in the modified solution obtained in (1), and heat treat it with stirring at 40-60°C for 2-4 hours; this step can form a corrosion inhibitor layer on the surface of the conductive filler. (3) After removing the solvent from the modified conductive filler mixture obtained in (2) by negative pressure filtration or centrifugation, wash it with ethanol 1 to 3 times and let it air dry at room temperature for 24 to 48 hours to ensure that the solvent is completely evaporated, and obtain the modified conductive powder. (4) Heat the feed chamber of the internal mixer to 120-160°C, add the rubber matrix, mix for 1-2 minutes, then add the silica and continue mixing for 10-30 minutes to obtain the mixed masterbatch. (5) The masterbatch obtained in step (4) is mixed with the vulcanizing agent of the formulation through a two-roll mill. The mixing temperature is controlled to be ≤40℃ and the mixing time is 4-6 minutes to obtain a first-stage rubber. (6) Add the section of rubber obtained in step (5) into the kneader, and add the modified conductive powder, plasticizer, antioxidant, ultraviolet absorber and metal ion passivator obtained in step (3) in sequence. After adding, knead for 10 to 20 minutes, control the kneading temperature to ≤40℃, and discharge the material to obtain the target broadband electromagnetic shielding rubber material.

[0024] Compared with existing technologies, the addition of conductive powder affects the dispersion of the vulcanizing agent, thus affecting the vulcanization effect (e.g., reducing the vulcanization speed, resulting in insufficient vulcanization of the compound). Therefore, the preparation method of the present invention adds the vulcanizing agent to the rubber matrix first, ensuring the uniform dispersion of the vulcanizing agent. Furthermore, if a traditional internal mixer is used for mixing, the strong shear strength of the internal mixer will cause wear and damage to the conductive filler to some extent during the mixing process. In addition, if the vulcanizing agent is added through an open mill after all the filler has been mixed evenly, the vulcanizing agent is difficult to disperse evenly at this point and can only be dispersed by increasing the number of thin passes. Due to the strong shear force during the thin passes in the open mill, the conductive powder coating will be severely damaged, affecting the conductivity of the material. The preparation method of this application avoids the above drawbacks. In addition, the conductive powder in this application is dispersed by a smaller kneader with adjustable shear force during mixing, which solves the problem of abrasion of conductive powder. The mixing time is strictly controlled, which effectively avoids wear of conductive powder during the mixing process. By strictly controlling the mixing temperature and discharge temperature, the scorching of the compound during vulcanization is effectively avoided.

[0025] This invention also claims protection for the application of the above-mentioned broadband electromagnetic shielding rubber material as electromagnetic shielding material for electronic shelters, including but not limited to: electromagnetic shielding sealing strips, gaskets and sealing rings and other electromagnetic shielding sealing products.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows: The mechanical properties of the broadband electromagnetic shielding rubber material prepared by this invention are as follows: Shore A hardness 75±5, tensile strength ≥3MPa, elongation at break ≥150%, volume resistivity ≤0.004Ω•cm, electromagnetic shielding effectiveness (30MHz-40GHz) ≥85dB, and electromagnetic shielding effectiveness retention rate ≥95% after damp heat (240h) / salt spray (240h) aging. The electromagnetic shielding rubber prepared by this invention meets the requirements for high-efficiency protection over a wide frequency range, satisfies the working environment and usage requirements of electronic shelter sealing components, and has excellent application prospects. Detailed Implementation

[0027] To better understand this invention, the following embodiments further illustrate its content. Obviously, the described embodiments are merely some, not all, of the embodiments of this invention. The specific embodiments described herein are only for explaining the invention and are not intended to limit it. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0028] Raw material composition of Examples 1-3 and Comparative Examples 1-2 The raw material composition (parts by weight) of the above embodiments and comparative examples is shown in Table 1 below: Table 1 .

[0029] The preparation method of Example 1 is as follows: (1) Dilute 4 parts of KH590 in 400 parts of acetone solution; add 30 parts of silver powder, 130 parts of silver-plated aluminum powder and 110 parts of nickel-plated carbon powder to the above mixture, stir at 50°C for 4 hours, filter, and then air dry at room temperature for 24 hours to obtain modified conductive powder. (2) Heat the feed chamber of the internal mixer to 140°C, add the rubber matrix, mix for 1-2 minutes, then add the silica and continue mixing for 20 minutes to obtain the mixed masterbatch. (3) The masterbatch obtained in step (2) is mixed with the vulcanizing agent of the formulation through a two-roll mill. The mixing temperature is controlled to be ≤40℃ and the mixture is mixed for 5 minutes to obtain a first-section rubber. (4) Add the section of rubber obtained in step (3) into the kneader, and add the modified conductive powder, plasticizer, antioxidant, ultraviolet absorber and metal ion passivator obtained in step (1) in sequence. After adding, knead for 15 minutes, control the kneading temperature to ≤40℃, and discharge the material to obtain the target broadband electromagnetic shielding rubber material.

[0030] The preparation method of Example 2 is the same as the method described above, except that: Step (1) involves diluting 6 parts of KH-802 in 400 parts of acetone solution; adding 35 parts of silver powder, 125 parts of silver-plated aluminum powder, and 115 parts of nickel-plated carbon powder to the above mixture, stirring at 60°C for 34 hours, filtering, and then drying at room temperature for 24 hours to obtain modified conductive powder; the remaining steps are the same as the above method.

[0031] The preparation method of Comparative Example 1 is as follows: (1) Dilute 4 parts of KH590 in 400 parts of acetone solution; add 30 parts of silver powder, 130 parts of silver-plated aluminum powder and 110 parts of nickel-plated carbon powder to the above mixture, stir at 50°C for 4 hours, filter, and then air dry at room temperature for 24 hours to obtain modified conductive powder. (2) Heat the feed chamber of the internal mixer to 140°C, add the rubber matrix, mix for 1-2 minutes, then add the silica and continue mixing for 20 minutes to obtain the mixed masterbatch. (3) Add the masterbatch obtained in step (2) into the internal mixer, and add the modified conductive powder, plasticizer, antioxidant, ultraviolet absorber and metal ion passivator obtained in step (1) in sequence. After adding, mix for 15 minutes and discharge.

[0032] (4) The compound obtained in step (3) and the vulcanizing agent of the formulation are mixed sequentially on a two-roll mill, passing through the mill 6-8 times, and then sheeting to obtain electromagnetic shielding rubber material.

[0033] The preparation method of Comparative Example 2 is as follows: (1) Heat the feed chamber of the internal mixer to 140°C, add the rubber matrix, mix for 1-2 minutes, then add the silica and continue mixing for 20 minutes to obtain the mixed masterbatch; (2) The masterbatch obtained in step (1) is mixed with the vulcanizing agent of the formulation through a two-roll mill. The mixing temperature is controlled to be ≤40℃ and the mixture is mixed for 5 minutes to obtain a first-section rubber. (3) Add the section of rubber obtained in step (2) into a kneader, and add the conductive powder, plasticizer, antioxidant, ultraviolet absorber and metal ion passivator in sequence. After adding, knead for 15 minutes, control the kneading temperature to ≤40℃, and discharge to obtain electromagnetic shielding rubber material.

[0034] The preparation method of Comparative Example 3 is basically the same as that of Comparative Example 2, except that: Step (3) Add the section of rubber obtained in step (2) into a kneader, and add the conductive powder and plasticizer in sequence. After adding, knead for 15 minutes, control the kneading temperature to ≤40℃, and discharge the material to obtain electromagnetic shielding rubber material.

[0035] In the experimental examples, the inventors conducted tests on the mechanical properties, electromagnetic shielding effectiveness, and aging performance of the electromagnetic shielding rubber materials of Examples 1-2 and Comparative Examples 1-3. The specific results are shown in Table 2. Table 2 As shown in Table 2, Comparative Example 1, using a traditional mixing method, suffered severe damage to the integrity of the conductive powder coating, resulting in a significant decrease in the material's electromagnetic shielding performance and aging resistance. Comparative Example 3, lacking a composite anti-aging system and with untreated conductive powder, exhibited an electromagnetic shielding effectiveness of only 51 dB before hygrothermal salt spray aging, which decreased to 68% of its original value after aging. Comparative Example 2, although a composite anti-aging system was added, lacked coupling agent treatment for the conductive powder, resulting in an electromagnetic shielding effectiveness of only 78 dB for the electromagnetic shielding compound. Furthermore, after hygrothermal salt spray aging, the shielding effectiveness decreased significantly to 77% of its original value. Compared to Comparative Example 1, Example 1, with its treated filler, showed a significant improvement in shielding effectiveness, increasing from 75 dB to 90 dB, a substantial 20% increase. Moreover, the material maintained a good electromagnetic shielding effectiveness retention rate after the hygrothermal salt spray test, ≥94%, demonstrating excellent aging resistance.

[0036] Experiment Example 2 The performance of the conductive rubber strip prepared using the compound rubber of Example 1, commercially available conventional conductive rubber strips, and the shielding wire mesh currently used in electronic shelters were tested. The results are shown in Table 3 below. Table 3 It is evident that the conductive rubber strips obtained by further preparing the compound rubber prepared in this application have significantly improved performance compared to commercially available conventional conductive rubber strips and the shielding mesh currently used in electronic cabins. They can be used as electromagnetic shielding materials for electronic cabins, including but not limited to: electromagnetic shielding sealing strips, sealing gaskets and sealing rings and other electromagnetic shielding sealing products.

[0037] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The description of the above embodiments can help understand the principles and methods of the present invention. However, the above embodiments are not unique and should not be construed as limiting the present invention. At the same time, those skilled in the art can make flexible changes to the specific implementation methods and application scope based on the principles and methods of the present invention.

Claims

1. A broadband electromagnetic shielding rubber material, characterized in that, Its raw material composition by weight is as follows: 100 parts by weight of rubber matrix 15-40 parts by weight of silica 180-300 parts by weight of conductive filler 1-4 parts by weight of plasticizer 2-8 parts by weight of coupling agent Compound anti-aging system 1.8–4 parts by weight 1 to 3 parts by weight of vulcanizing agent.

2. The broadband electromagnetic shielding rubber material according to claim 1, characterized in that, The rubber matrix is ​​methyl vinyl silicone rubber, wherein the vinyl content in the methyl vinyl silicone rubber is 0.05-0.12%; the particle size of the silica is controlled between 12 and 200 nm, specifically one of HL-200, TS-530, HB-630, and RD-201.

3. The broadband electromagnetic shielding rubber material according to claim 1, characterized in that, The conductive filler is a compound of silver powder, silver-plated aluminum powder, and nickel-plated carbon powder in a specific ratio of (20-40):(80-140):(80-120); wherein the pure silver powder has a silver content of ≥97% and a particle size of 80-120 μm; the silver content of the silver-plated aluminum powder is 10-30% and the particle size is 10-50 μm; and the nickel-plated carbon powder has a nickel content of ≥60% and a particle size of 100-150 μm.

4. The broadband electromagnetic shielding rubber material according to claim 1, characterized in that, The amount of conductive filler used is 250-300 parts by weight.

5. The broadband electromagnetic shielding rubber material according to claim 1, characterized in that, The coupling agent is a mercapto-containing silane coupling agent, selected from one of KH590, A189, and KH-802.

6. The broadband electromagnetic shielding rubber material according to claim 1, characterized in that, The plasticizer is a hydroxyl silicone oil, and the antioxidant is a hindered phenolic antioxidant; the compound anti-aging system is a combination of three substances: antioxidant, ultraviolet absorber, and metal particle passivator, in a weight ratio of (0.5-1):(0.3-1):(1-2).

7. The broadband electromagnetic shielding rubber material according to claim 6, characterized in that, The plasticizer is one of OH-72, OH-82, OH-81, and JF-203; the antioxidant is one of 1010 and 1790; the ultraviolet absorber is one of UV-531, UV-327, and HALS; the metal particle passivator is one or more of PVP-K30, SY-88, and TEGO Protect5000; and the vulcanizing agent is one of dicumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butyl peroxide), and di-(tert-butylperoxyisopropyl)phenylhexane.

8. The method for preparing the broadband electromagnetic shielding rubber material according to claim 1, characterized in that, The specific steps are as follows: (1) Mix the coupling agent and the dispersing solvent evenly to obtain a modified solution. The amount of the dispersing solvent is 50 to 100 times the mass of the coupling agent. The dispersing solvent used is acetone or anhydrous ethanol. (2) Disperse the conductive filler in the modified solution obtained in (1) by stirring, and heat treat it by stirring at 40-60°C for 2-4 hours; (3) After the modified conductive filler mixture obtained in (2) is desolventized by negative pressure filtration or centrifugation, it is washed with ethanol 1 to 3 times and left to dry at room temperature for 24 to 48 hours to obtain modified conductive powder. (4) Heat the feed chamber of the internal mixer to 120-160°C, add the rubber matrix, mix for 1-2 minutes, then add the silica and continue mixing for 10-30 minutes to obtain the mixed masterbatch. (5) The masterbatch obtained in step (4) is mixed with the vulcanizing agent of the formulation through a two-roll mill. The mixing temperature is controlled to be ≤40℃ and the mixing time is 4-6 minutes to obtain a first-stage rubber. (6) Add the section of rubber obtained in step (5) into the kneader, and add the modified conductive powder, plasticizer, antioxidant, ultraviolet absorber and metal ion passivator obtained in step (3) in sequence. After adding, knead for 10 to 20 minutes, control the kneading temperature to ≤40℃, and discharge the material to obtain the target broadband electromagnetic shielding rubber material.

9. The application of the broadband electromagnetic shielding rubber material of claim 1 as an electromagnetic shielding material for electronic shelters.

10. The application according to claim 9, characterized in that: Electromagnetic shielding materials for electronic modular shelters include, but are not limited to: electromagnetic shielding sealing strips, gaskets and sealing rings, and various electromagnetic shielding sealing products.

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