Shielding cover based on silicone rubber conductive adhesive and preparation method thereof

Abstract

The invention relates to the technical field of electromagnetic shielding materials, in particular to a shielding cover based on silicone rubber conductive adhesive and a preparation method of the shielding cover. Aluminum magnesium alloy raw materials are subjected to die-casting forming, and the shielding shell is obtained; a composite magnetic adhesive, a silver-loaded-copper conductive composite adhesive and a silver-loaded conductive composite adhesive are sequentially dispensed at the fixed position of the shielding cover, and a finished product is obtained through vulcanization and packaging. The finished product prepared by the invention has excellent electromagnetic shielding performance, so that the electromagnetic shielding material has a wide application prospect in the technical field of electromagnetic shielding materials.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic shielding materials, in particular to a shielding cover based on silicone rubber conductive adhesive and a preparation method thereof. Background Art

[0002] In today's rapidly advancing technology, electronic devices permeate every corner of our lives. Shielding covers, as key components in electronic devices, are playing a significant role in modern life. As electronic devices become increasingly powerful, their internal electronic components become densely packed and operate at extremely high speeds, creating a significant challenge for electromagnetic interference. Shielding covers based on silicone rubber conductive adhesive can effectively block mutual interference between electromagnetic signals, creating a pure operating environment for electronic components. For example, in smartphones, shielding covers prevent interference between chip modules, ensuring stable signals and smooth operation during calls, browsing the internet, gaming, and other activities, significantly enhancing the user experience.

[0003] However, with the increasing integration of electronic devices, numerous electronic components are closely packed together. These components generate complex electromagnetic signals during operation. Interference between these signals can lead to performance degradation and problems such as data transmission errors, signal loss, and malfunction. Applying conductive silicone rubber adhesive to fixed locations on the shielding cover effectively prevents signal leakage through the gaps in the cover, effectively blocking electromagnetic interference and ensuring independent and stable operation of components within the electronic device, safeguarding the overall performance and reliability of the device.

[0004] In order to overcome the defects of the prior art, the present invention provides a shielding cover based on silicone rubber conductive adhesive and a preparation method thereof. Summary of the Invention

[0005] The object of the present invention is to provide a shielding cover based on silicone rubber conductive adhesive and a preparation method thereof, so as to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions: A method for preparing a shielding cover based on silicone rubber conductive adhesive comprises the following steps: die-casting an aluminum-magnesium alloy raw material to obtain a shielding shell; sequentially applying a composite magnetic adhesive, a silver-copper conductive composite adhesive, and a silver-loaded conductive composite adhesive to a fixed position of the shielding cover, vulcanizing the shielding cover at 100-120°C for 30-40 minutes, and packaging the shielding cover to obtain a finished product.

[0007] More optimally, in parts by mass, 20-25 parts of composite magnetic material, 50-60 parts of vinyl polysiloxane, 8-10 parts of hydrogen-containing polysiloxane, 0.02-0.03 parts of chloroplatinic acid, and 0.02-0.03 parts of methylpentynol are mixed to obtain a composite magnetic adhesive; 20-25 parts of silver-loaded-copper conductive composite material, 50-60 parts of vinyl polysiloxane, 8-10 parts of hydrogen-containing polysiloxane, 0.02-0.03 parts of chloroplatinic acid, and 0.02-0.03 parts of methylpentynol are mixed to obtain a silver-loaded-copper conductive composite adhesive; 20-25 parts of silver-loaded conductive composite material, 50-60 parts of vinyl polysiloxane, 8-10 parts of hydrogen-containing polysiloxane, 0.02-0.03 parts of chloroplatinic acid, and 0.02-0.03 parts of methylpentynol are mixed to obtain a silver-loaded conductive composite adhesive.

[0008] More optimally, the preparation process of the silver-loaded conductive composite material and the silver-loaded-copper conductive composite material is as follows: Step S1: adding polymethyl methacrylate powder to deionized water to obtain polymethyl methacrylate solution; then adding Ti3C2T X MXene powder is added to a polymethyl methacrylate solution, stirred thoroughly for 25-30 minutes, and centrifuged to obtain a composite material. The composite material and graphene oxide are then added to deionized water, stirred thoroughly for 3-4 hours under an argon atmosphere, and freeze-dried to obtain a conductive composite material. The conductive composite material is heat-treated at 440-450°C under an argon atmosphere for 1.2-1.5 hours to obtain a porous conductive composite material. Step S2: adding silver nitrate to deionized water to obtain a silver nitrate solution; then adding the porous conductive composite material, ultrasonically dispersing for 20-30 minutes, then adding ethylene glycol, and continuing ultrasonically dispersing for 15-20 minutes. After uniform dispersion, react in a water bath at 35-40° C. for 15-20 hours. After the reaction is completed, cooling, centrifuging, washing, and drying to obtain a silver-loaded conductive composite material; Step S3: adding polyvinyl alcohol to deionized water to obtain a polyvinyl alcohol solution; adding silver nitrate to deionized water to obtain a silver nitrate solution; adding copper nitrate trihydrate to deionized water to obtain a copper nitrate solution; mixing the silver nitrate solution and the copper nitrate solution, stirring evenly, then adding the porous conductive composite material, ultrasonically dispersing for 20-30 minutes, then adding the polyvinyl alcohol solution, continuing ultrasonic dispersion for 15-20 minutes, and after uniform dispersion, reacting in a water bath at 80-90°C for 1.0-1.5 hours. After the reaction is completed, cooling, centrifuging, washing, and drying are performed to obtain a silver-copper conductive composite material.

[0009] More optimally, in step S1, polymethyl methacrylate powder, Ti3C2T X The reaction mass ratio of MXene powder and graphene oxide is (6-7):1:(4-5).

[0010] More optimally, in step S2, when preparing the silver-loaded conductive composite material, the mass volume ratio of silver nitrate, porous conductive composite material, and ethylene glycol is (0.35-0.40) g:2.5 g:20 mL.

[0011] More optimally, in step S3, the reaction mass ratio of silver nitrate, copper nitrate trihydrate, porous conductive composite material, and polyvinyl alcohol is 0.15: (0.075-0.078): 1.8: 7.5.

[0012] More optimally, the preparation process of the composite magnetic material is: Step S1: adding xylose to deionized water to obtain a 0.45-0.50 mol / L xylose solution; heat-treating the xylose solution at 180-200° C. for 11-13 hours, cooling, filtering, washing, and drying after the reaction to obtain carbon microspheres; Step S2: adding carbon microspheres to deionized water, and adding sodium hydroxide to adjust the pH to 11.0-11.2 to obtain a carbon microsphere solution; adding nickel nitrate hexahydrate and ferric nitrate nonahydrate to deionized water to obtain a salt solution; adding the salt solution dropwise to the carbon microsphere solution, and then adding urea and ammonium fluoride after the addition is completed, ultrasonically dispersing the mixture, reacting at 110-120° C. for 11-13 hours, and cooling, washing, and drying the mixture after the reaction is completed to obtain a carbon microsphere-hydrotalcite composite material; Step S3: adding ferrous sulfate heptahydrate and ferric nitrate nonahydrate to deionized water and stirring thoroughly to obtain an iron salt solution; then adding the carbon microsphere-hydrotalcite composite material and deionized water to the iron salt solution, ultrasonically dispersing the mixture uniformly, adding sodium hydroxide to adjust the pH to 10.0-10.2, and reacting in a water bath at 80-85° C. for 20-30 minutes. After the reaction is completed, the mixture is cooled, washed, and dried to obtain a composite magnetic material.

[0013] More optimally, in step S2, the reaction mass ratio of carbon microspheres, nickel nitrate hexahydrate, ferric nitrate nonahydrate, urea, and ammonium fluoride is (0.08-0.1): 0.22: 0.1: 0.35: 0.08.

[0014] More optimally, in step S3, the reaction mass ratio of ferrous sulfate heptahydrate, ferric nitrate nonahydrate, and carbon microsphere-hydrotalcite composite material is 0.07:0.17:(0.02-0.03).

[0015] Beneficial effects of the present invention: The present invention is characterized in that by adding polymethyl methacrylate, Ti3C2T XMXene powder and graphene oxide are used to obtain a conductive composite material. After high-temperature heat treatment, polymethyl methacrylate decomposes and graphene oxide undergoes thermal reduction, so the conductive composite material becomes a porous conductive composite material. The porous structure greatly increases the specific surface area of ​​the material, allowing electromagnetic waves to have more propagation paths and reflection interfaces inside the material. When electromagnetic waves enter the porous structure, they will continuously reflect and scatter between the pore walls, thereby consuming a large amount of energy. In addition, the conductive material reduces graphene oxide and Ti3C2T X MXenes are intertwined with each other and can form a conductive network within the composite material.

[0016] Furthermore, a silver-loaded conductive composite material is obtained by adding a porous conductive composite material, ethylene glycol, and silver nitrate to a chemical reduction method; and a silver-loaded conductive composite adhesive is obtained by mixing the silver-loaded conductive composite material, vinyl polysiloxane, hydrogen-containing polysiloxane, chloroplatinic acid, and methylpentynol. Silver is introduced into the porous conductive composite material by adding ethylene glycol and silver nitrate and using a chemical reduction method. Silver is a metal with excellent conductivity, and the silver particles are evenly distributed in the pores and surface of the porous conductive composite material, further enhancing the conductivity of the material. The silver particles interact with the porous structure and other conductive components, further increasing the chances of electromagnetic waves being scattered and absorbed within the material.

[0017] Furthermore, a porous conductive composite material, polyvinyl alcohol, silver nitrate, and copper nitrate trihydrate were added and subjected to in-situ reduction in a water bath to obtain a silver-copper conductive composite material. The silver-copper conductive composite material was then mixed with vinyl polysiloxane, hydrogen-containing polysiloxane, chloroplatinic acid, and methylpentynol to obtain a silver-copper conductive composite adhesive. Silver and copper, both highly conductive metals, are evenly distributed throughout the pores and surface of the porous conductive composite material. This not only further enhances the material's conductivity and its ability to reflect electromagnetic waves, but also the silver and copper nanoparticles synergize with the porous structure and other components to increase the scattering and absorption of electromagnetic waves within the material.

[0018] The present invention is characterized in that xylose, nickel nitrate hexahydrate, ferric nitrate nonahydrate, urea, and ammonium fluoride are added to form a carbon microsphere-hydrotalcite composite material. The carbon microsphere-hydrotalcite composite material, ferrous sulfate heptahydrate, and ferric nitrate nonahydrate are added to coat the surface of the carbon microsphere-hydrotalcite composite material with a ferroferric oxide magnetic material to form a composite magnetic material. The composite magnetic material is then mixed with vinyl polysiloxane, hydrogen-containing polysiloxane, chloroplatinic acid, and methylpentynol to form a composite magnetic adhesive.

[0019] The carbon microspheres possess a certain degree of conductivity, while metal ions such as nickel and iron in the hydrotalcite structure impart a degree of magnetism. The coating of ferroferric oxide, a highly magnetic material, significantly enhances the magnetic properties of the entire composite magnetic material. Magnetic materials interact with the magnetic field component of electromagnetic waves, generating hysteresis and eddy current losses, converting the energy of the electromagnetic waves into heat, thereby effectively absorbing them. Therefore, this composite magnetic adhesive leverages the fundamental properties of the carbon microsphere-hydrotalcite composite, the reinforcing effect of the composite magnetic material, and the synergistic effects of the various components within the adhesive to form a highly effective electromagnetic shielding system, resulting in excellent electromagnetic shielding performance.

[0020] The aluminum-magnesium alloy raw material is die-cast to obtain a shielding shell; then a composite magnetic adhesive, a silver-copper conductive composite adhesive, and a silver-copper conductive composite adhesive are sequentially applied to the fixed position of the shielding cover, and after vulcanization and packaging, a shielding cover based on silicone rubber conductive adhesive is obtained. The advantage of this adhesive structure setting is that: first, the composite magnetic adhesive is applied, and by utilizing its unique magnetic microstructure and electromagnetic properties, it can preferentially interact with external electromagnetic waves, efficiently absorb electromagnetic wave energy and convert it into other forms of energy such as heat energy, thereby achieving preliminary processing of electromagnetic waves. Then, on the basis of the coated composite magnetic adhesive, the silver-copper conductive composite adhesive is applied. Due to the metallic silver, copper and Ti3C2T X MXene powder and reduced graphene oxide exhibit excellent electrical conductivity, and this adhesive possesses high electrical conductivity, forming a conductive network within it. When the remaining electromagnetic waves, after being absorbed by the composite magnetic adhesive, enter this adhesive layer, they are continuously reflected within this conductive network. Each reflection is accompanied by energy loss, resulting in multiple reflection attenuation, further reducing the intensity of the electromagnetic waves. Finally, a silver-loaded conductive composite adhesive is applied. This adhesive has moderate conductivity and further processes the electromagnetic waves after multiple reflections and attenuation by the silver-copper conductive composite adhesive. Similarly, multiple reflections within the adhesive layer further dissipate the electromagnetic wave's energy, achieving secondary multiple reflection attenuation.

[0021] In summary, the finished product prepared by the present invention has excellent electromagnetic shielding performance, and therefore has broad application prospects in the field of electromagnetic shielding material technology. DETAILED DESCRIPTION

[0022] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0023] Source of raw materials: Polymethyl methacrylate powder, provided by Ruixiang Plastics Company, with an average microsphere diameter of 3 μm; Ti3C2T X MXene powder, provided by Forsman Technology (Beijing) Co., Ltd., model 2203006; graphene oxide, provided by Changzhou Yaobang Friction Material Factory, particle size 2nm; polyvinyl alcohol, provided by Kaimaoxing (Hebei) Cellulose Co., Ltd., molecular weight 120,000; xylose, provided by Henan Qinuo Food Ingredients Co., Ltd., XOS-35; hydrogenated polysiloxane, provided by Shandong Qimin Chemical Technology Co., Ltd., molecular weight 222.5; vinyl polysiloxane, Shandong Huachen New Materials Co., Ltd., model HC04; in terms of mass, one portion is 1g.

[0024] Example 1: Step S1: adding polymethyl methacrylate powder to deionized water to obtain a polymethyl methacrylate solution; then adding Ti3C2T X MXene powder was added to polymethyl methacrylate solution, stirred for 30 minutes, and centrifuged to obtain a composite material; the composite material and graphene oxide were then added to deionized water, stirred for 4 hours under an argon environment, and freeze-dried to obtain a conductive composite material; the conductive composite material was heat-treated at 450°C for 1.5 hours under an argon environment to obtain a porous conductive composite material; polymethyl methacrylate powder, Ti3C2T X The reaction mass ratio of MXene powder and graphene oxide is 6.5:1:4.5; Step S2: adding silver nitrate to deionized water to obtain a silver nitrate solution; then adding the porous conductive composite material, ultrasonically dispersing for 30 minutes, and then adding ethylene glycol, continuing ultrasonic dispersion for 20 minutes, and reacting in a 40°C water bath for 20 hours after uniform dispersion. After the reaction is completed, cooling, centrifuging, washing, and drying to obtain a silver-loaded conductive composite material; the mass volume ratio of silver nitrate, porous conductive composite material, and ethylene glycol is 0.37g:2.5g:20mL; Step S3: adding polyvinyl alcohol to deionized water to obtain a polyvinyl alcohol solution; adding silver nitrate to deionized water to obtain a silver nitrate solution; adding copper nitrate trihydrate to deionized water to obtain a copper nitrate solution; mixing the silver nitrate solution and the copper nitrate solution, stirring evenly, then adding the porous conductive composite material, ultrasonically dispersing for 30 minutes, then adding the polyvinyl alcohol solution, continuing ultrasonic dispersion for 20 minutes, and reacting in a 90°C water bath for 1.5 hours after uniform dispersion. After the reaction is completed, cooling, centrifuging, washing, and drying to obtain a silver-copper conductive composite material; the reaction mass ratio of silver nitrate, copper nitrate trihydrate, porous conductive composite material, and polyvinyl alcohol is 0.15:0.076:1.8:7.5; Step S4: adding xylose to deionized water to obtain a 0.50 mol / L xylose solution; heat-treating the xylose solution at 200° C. for 13 h, and cooling, filtering, washing, and drying the solution after the reaction to obtain carbon microspheres; Step S5: adding carbon microspheres to deionized water, and adding sodium hydroxide to adjust the pH to 11.2 to obtain a carbon microsphere solution; adding nickel nitrate hexahydrate and ferric nitrate nonahydrate to deionized water to obtain a salt solution; adding the salt solution dropwise to the carbon microsphere solution, and then adding urea and ammonium fluoride after the addition is completed, and then ultrasonically dispersed and reacted at 120° C. for 13 hours. After the reaction is completed, the mixture is cooled, washed, and dried to obtain a carbon microsphere-hydrotalcite composite material; the reaction mass ratio of carbon microspheres, nickel nitrate hexahydrate, ferric nitrate nonahydrate, urea, and ammonium fluoride is 0.09:0.22:0.1:0.35:0.08; Step S6: adding ferrous sulfate heptahydrate and ferric nitrate nonahydrate to deionized water and stirring thoroughly to obtain an iron salt solution; then adding the carbon microsphere-hydrotalcite composite material and deionized water to the iron salt solution, ultrasonically dispersing the mixture uniformly, adding sodium hydroxide to adjust the pH to 10.2, and reacting the mixture in a water bath at 85° C. for 30 minutes. After the reaction is completed, the mixture is cooled, washed, and dried to obtain a composite magnetic material; the reaction mass ratio of ferrous sulfate heptahydrate, ferric nitrate nonahydrate, and carbon microsphere-hydrotalcite composite material is 0.07:0.17:0.025; Step S7: 25 g of composite magnetic material, 60 g of vinyl polysiloxane, 10 g of hydrogen-containing polysiloxane, 0.03 g of chloroplatinic acid, and 0.03 g of methylpentynol are mixed to obtain a composite magnetic adhesive; 25 g of silver-loaded copper conductive composite material, 60 g of vinyl polysiloxane, 10 g of hydrogen-containing polysiloxane, 0.03 g of chloroplatinic acid, and 0.03 g of methylpentynol are mixed to obtain a silver-loaded copper conductive composite adhesive; 25 g of silver-loaded conductive composite material, 60 g of vinyl polysiloxane, 10 g of hydrogen-containing polysiloxane, 0.03 g of chloroplatinic acid, and 0.03 g of methylpentynol are mixed to obtain a silver-loaded conductive composite adhesive; A shielding shell is obtained by die-casting an aluminum-magnesium alloy raw material; a composite magnetic adhesive, a silver-copper conductive composite adhesive, and a silver-loaded conductive composite adhesive are sequentially applied to a fixed position of the shielding cover, and the shielding shell is vulcanized at 120° C. for 40 minutes and packaged to obtain a finished product.

[0025] Example 2: Step S1: adding polymethyl methacrylate powder to deionized water to obtain a polymethyl methacrylate solution; then adding Ti3C2T XMXene powder was added to polymethyl methacrylate solution, stirred for 27 minutes, and centrifuged to obtain a composite material. The composite material and graphene oxide were then added to deionized water, stirred for 3.5 hours under an argon environment, and freeze-dried to obtain a conductive composite material. The conductive composite material was heat-treated at 445°C for 1.3 hours under an argon environment to obtain a porous conductive composite material. Polymethyl methacrylate powder, Ti3C2T X The reaction mass ratio of MXene powder and graphene oxide is 6.5:1:4.5; Step S2: adding silver nitrate to deionized water to obtain a silver nitrate solution; then adding the porous conductive composite material, ultrasonically dispersing for 25 minutes, and then adding ethylene glycol, continuing ultrasonic dispersion for 17 minutes, and reacting in a 37°C water bath for 17 hours after uniform dispersion. After the reaction is completed, cooling, centrifuging, washing, and drying to obtain a silver-loaded conductive composite material; the mass volume ratio of silver nitrate, porous conductive composite material, and ethylene glycol is 0.37 g:2.5 g:20 mL; Step S3: adding polyvinyl alcohol to deionized water to obtain a polyvinyl alcohol solution; adding silver nitrate to deionized water to obtain a silver nitrate solution; adding copper nitrate trihydrate to deionized water to obtain a copper nitrate solution; mixing the silver nitrate solution and the copper nitrate solution, stirring evenly, then adding the porous conductive composite material, ultrasonically dispersing for 25 minutes, then adding the polyvinyl alcohol solution, continuing ultrasonic dispersion for 17 minutes, and reacting in an 85°C water bath for 1.2 hours after uniform dispersion. After the reaction, cooling, centrifuging, washing, and drying to obtain a silver-copper conductive composite material; the reaction mass ratio of silver nitrate, copper nitrate trihydrate, porous conductive composite material, and polyvinyl alcohol is 0.15:0.076:1.8:7.5; Step S4: adding xylose to deionized water to obtain a 0.50 mol / L xylose solution; heat-treating the xylose solution at 190° C. for 12 h, and cooling, filtering, washing, and drying the solution after the reaction to obtain carbon microspheres; Step S5: adding carbon microspheres to deionized water, and adding sodium hydroxide to adjust the pH to 11.1 to obtain a carbon microsphere solution; adding nickel nitrate hexahydrate and ferric nitrate nonahydrate to deionized water to obtain a salt solution; adding the salt solution dropwise to the carbon microsphere solution, and then adding urea and ammonium fluoride after the addition is completed, and then ultrasonically dispersed and reacted at 115° C. for 12 hours. After the reaction is completed, the mixture is cooled, washed, and dried to obtain a carbon microsphere-hydrotalcite composite material; the reaction mass ratio of carbon microspheres, nickel nitrate hexahydrate, ferric nitrate nonahydrate, urea, and ammonium fluoride is 0.09:0.22:0.1:0.35:0.08; Step S6: adding ferrous sulfate heptahydrate and ferric nitrate nonahydrate to deionized water and stirring thoroughly to obtain an iron salt solution; then adding the carbon microsphere-hydrotalcite composite material and deionized water to the iron salt solution, ultrasonically dispersing the mixture uniformly, adding sodium hydroxide to adjust the pH to 10.1, and reacting in a water bath at 82° C. for 25 minutes. After the reaction is completed, cooling, washing, and drying are performed to obtain a composite magnetic material; the reaction mass ratio of ferrous sulfate heptahydrate, ferric nitrate nonahydrate, and carbon microsphere-hydrotalcite composite material is 0.07:0.17:0.025; Step S7: 25 g of composite magnetic material, 60 g of vinyl polysiloxane, 10 g of hydrogen-containing polysiloxane, 0.03 g of chloroplatinic acid, and 0.03 g of methylpentynol are mixed to obtain a composite magnetic adhesive; 25 g of silver-loaded copper conductive composite material, 60 g of vinyl polysiloxane, 10 g of hydrogen-containing polysiloxane, 0.03 g of chloroplatinic acid, and 0.03 g of methylpentynol are mixed to obtain a silver-loaded copper conductive composite adhesive; 25 g of silver-loaded conductive composite material, 60 g of vinyl polysiloxane, 10 g of hydrogen-containing polysiloxane, 0.03 g of chloroplatinic acid, and 0.03 g of methylpentynol are mixed to obtain a silver-loaded conductive composite adhesive; A shielding shell is obtained by die-casting an aluminum-magnesium alloy raw material; a composite magnetic adhesive, a silver-copper conductive composite adhesive, and a silver-loaded conductive composite adhesive are sequentially applied to a fixed position of the shielding cover, and the shielding shell is vulcanized at 110° C. for 35 minutes and packaged to obtain a finished product.

[0026] Example 3: Step S1: adding polymethyl methacrylate powder to deionized water to obtain polymethyl methacrylate solution; then adding Ti3C2T X MXene powder was added to polymethyl methacrylate solution, stirred for 25 minutes, and centrifuged to obtain a composite material; the composite material and graphene oxide were then added to deionized water, stirred for 3 hours under an argon environment, and freeze-dried to obtain a conductive composite material; the conductive composite material was heat-treated at 440°C for 1.2 hours under an argon environment to obtain a porous conductive composite material; polymethyl methacrylate powder, Ti3C2T X The reaction mass ratio of MXene powder and graphene oxide is 6.5:1:4.5; Step S2: adding silver nitrate to deionized water to obtain a silver nitrate solution; then adding the porous conductive composite material, ultrasonically dispersing for 20 minutes, and then adding ethylene glycol, continuing ultrasonic dispersion for 15 minutes, and reacting in a 35°C water bath for 15 hours after uniform dispersion. After the reaction is completed, cooling, centrifuging, washing, and drying to obtain a silver-loaded conductive composite material; the mass volume ratio of silver nitrate, porous conductive composite material, and ethylene glycol is 0.37g:2.5g:20mL; Step S3: adding polyvinyl alcohol to deionized water to obtain a polyvinyl alcohol solution; adding silver nitrate to deionized water to obtain a silver nitrate solution; adding copper nitrate trihydrate to deionized water to obtain a copper nitrate solution; mixing the silver nitrate solution and the copper nitrate solution, stirring evenly, then adding the porous conductive composite material, ultrasonically dispersing for 20 minutes, then adding the polyvinyl alcohol solution, continuing ultrasonic dispersion for 15 minutes, and after uniform dispersion, reacting in an 80°C water bath for 1.0 hour. After the reaction is completed, cooling, centrifuging, washing, and drying to obtain a silver-copper conductive composite material; the reaction mass ratio of silver nitrate, copper nitrate trihydrate, porous conductive composite material, and polyvinyl alcohol is 0.15:0.076:1.8:7.5; Step S4: adding xylose to deionized water to obtain a 0.50 mol / L xylose solution; heat-treating the xylose solution at 180° C. for 11 h, and cooling, filtering, washing, and drying the solution after the reaction to obtain carbon microspheres; Step S5: adding carbon microspheres to deionized water, and adding sodium hydroxide to adjust the pH to 11 to obtain a carbon microsphere solution; adding nickel nitrate hexahydrate and ferric nitrate nonahydrate to deionized water to obtain a salt solution; adding the salt solution dropwise to the carbon microsphere solution, and then adding urea and ammonium fluoride after the addition is completed, and then ultrasonically dispersed and reacted at 110° C. for 11 hours. After the reaction is completed, the mixture is cooled, washed, and dried to obtain a carbon microsphere-hydrotalcite composite material; the reaction mass ratio of carbon microspheres, nickel nitrate hexahydrate, ferric nitrate nonahydrate, urea, and ammonium fluoride is 0.09:0.22:0.1:0.35:0.08; Step S6: adding ferrous sulfate heptahydrate and ferric nitrate nonahydrate to deionized water and stirring thoroughly to obtain an iron salt solution; then adding the carbon microsphere-hydrotalcite composite material and deionized water to the iron salt solution, ultrasonically dispersing the mixture uniformly, adding sodium hydroxide to adjust the pH to 10, and reacting the mixture in an 80° C. water bath for 20 minutes. After the reaction is completed, the mixture is cooled, washed, and dried to obtain a composite magnetic material; the reaction mass ratio of ferrous sulfate heptahydrate, ferric nitrate nonahydrate, and carbon microsphere-hydrotalcite composite material is 0.07:0.17:0.025; Step S7: 25 g of composite magnetic material, 60 g of vinyl polysiloxane, 10 g of hydrogen-containing polysiloxane, 0.03 g of chloroplatinic acid, and 0.03 g of methylpentynol are mixed to obtain a composite magnetic adhesive; 25 g of silver-loaded copper conductive composite material, 60 g of vinyl polysiloxane, 10 g of hydrogen-containing polysiloxane, 0.03 g of chloroplatinic acid, and 0.03 g of methylpentynol are mixed to obtain a silver-loaded copper conductive composite adhesive; 25 g of silver-loaded conductive composite material, 60 g of vinyl polysiloxane, 10 g of hydrogen-containing polysiloxane, 0.03 g of chloroplatinic acid, and 0.03 g of methylpentynol are mixed to obtain a silver-loaded conductive composite adhesive; A shielding shell is obtained by die-casting an aluminum-magnesium alloy raw material; a composite magnetic adhesive, a silver-copper conductive composite adhesive, and a silver-loaded conductive composite adhesive are sequentially applied to a fixed position of the shielding cover, and the shielding shell is vulcanized at 100° C. for 30 minutes and packaged to obtain a finished product.

[0027] Comparative Example 1: The silver-loaded conductive composite adhesive was removed, and the rest was the same as in Example 1. The specific steps were as follows: Step S1: polymethyl methacrylate powder was added to deionized water to obtain a polymethyl methacrylate solution; Ti3C2T X MXene powder was added to polymethyl methacrylate solution, stirred for 30 minutes, and centrifuged to obtain a composite material; the composite material and graphene oxide were then added to deionized water, stirred for 4 hours under an argon environment, and freeze-dried to obtain a conductive composite material; the conductive composite material was heat-treated at 450°C for 1.5 hours under an argon environment to obtain a porous conductive composite material; polymethyl methacrylate powder, Ti3C2T X The reaction mass ratio of MXene powder and graphene oxide is 6.5:1:4.5; Step S2: adding polyvinyl alcohol to deionized water to obtain a polyvinyl alcohol solution; adding silver nitrate to deionized water to obtain a silver nitrate solution; adding copper nitrate trihydrate to deionized water to obtain a copper nitrate solution; mixing the silver nitrate solution and the copper nitrate solution, stirring evenly, then adding the porous conductive composite material, ultrasonically dispersing for 30 minutes, then adding the polyvinyl alcohol solution, continuing ultrasonic dispersion for 20 minutes, and reacting in a 90°C water bath for 1.5 hours after uniform dispersion. After the reaction is completed, cooling, centrifuging, washing, and drying to obtain a silver-copper conductive composite material; the reaction mass ratio of silver nitrate, copper nitrate trihydrate, porous conductive composite material, and polyvinyl alcohol is 0.15:0.076:1.8:7.5; Step S3: adding xylose to deionized water to obtain a 0.50 mol / L xylose solution; heat-treating the xylose solution at 200° C. for 13 h, and cooling, filtering, washing, and drying the solution after the reaction to obtain carbon microspheres; Step S4: adding carbon microspheres to deionized water, and adding sodium hydroxide to adjust the pH to 11.2 to obtain a carbon microsphere solution; adding nickel nitrate hexahydrate and ferric nitrate nonahydrate to deionized water to obtain a salt solution; adding the salt solution dropwise to the carbon microsphere solution, and then adding urea and ammonium fluoride after the addition is completed, and then ultrasonically dispersed and reacted at 120° C. for 13 hours. After the reaction is completed, the mixture is cooled, washed, and dried to obtain a carbon microsphere-hydrotalcite composite material; the reaction mass ratio of carbon microspheres, nickel nitrate hexahydrate, ferric nitrate nonahydrate, urea, and ammonium fluoride is 0.09:0.22:0.1:0.35:0.08; Step S5: adding ferrous sulfate heptahydrate and ferric nitrate nonahydrate to deionized water and stirring thoroughly to obtain an iron salt solution; then adding the carbon microsphere-hydrotalcite composite material and deionized water to the iron salt solution, ultrasonically dispersing the mixture uniformly, adding sodium hydroxide to adjust the pH to 10.2, and reacting the mixture in a water bath at 85° C. for 30 minutes. After the reaction is completed, the mixture is cooled, washed, and dried to obtain a composite magnetic material; the reaction mass ratio of ferrous sulfate heptahydrate, ferric nitrate nonahydrate, and carbon microsphere-hydrotalcite composite material is 0.07:0.17:0.025; Step S6: 25 g of composite magnetic material, 60 g of vinyl polysiloxane, 10 g of hydrogen-containing polysiloxane, 0.03 g of chloroplatinic acid, and 0.03 g of methylpentynol are mixed to obtain a composite magnetic adhesive; 25 g of silver-loaded-copper conductive composite material, 60 g of vinyl polysiloxane, 10 g of hydrogen-containing polysiloxane, 0.03 g of chloroplatinic acid, and 0.03 g of methylpentynol are mixed to obtain a silver-loaded-copper conductive composite adhesive; A shielding shell is obtained by die-casting an aluminum-magnesium alloy raw material; a composite magnetic adhesive and a silver-copper conductive composite adhesive are sequentially applied to a fixed position of the shielding cover, and the shielding cover is vulcanized at 120° C. for 40 minutes and packaged to obtain a finished product.

[0028] Comparative Example 2: The silver-copper conductive composite adhesive and the silver-loaded conductive composite adhesive were removed, and the rest was the same as in Example 1, with the following specific steps: Step S1: xylose was added to deionized water to obtain a 0.50 mol / L xylose solution; the xylose solution was heat-treated at 200° C. for 13 h, and after the reaction was completed, the solution was cooled, filtered, washed, and dried to obtain carbon microspheres; Step S2: adding carbon microspheres to deionized water, and adding sodium hydroxide to adjust the pH to 11.2 to obtain a carbon microsphere solution; adding nickel nitrate hexahydrate and ferric nitrate nonahydrate to deionized water to obtain a salt solution; adding the salt solution dropwise to the carbon microsphere solution, and then adding urea and ammonium fluoride after the addition is completed, and then ultrasonically dispersed and reacted at 120° C. for 13 hours. After the reaction is completed, the mixture is cooled, washed, and dried to obtain a carbon microsphere-hydrotalcite composite material; the reaction mass ratio of carbon microspheres, nickel nitrate hexahydrate, ferric nitrate nonahydrate, urea, and ammonium fluoride is 0.09:0.22:0.1:0.35:0.08; Step S3: adding ferrous sulfate heptahydrate and ferric nitrate nonahydrate to deionized water and stirring thoroughly to obtain an iron salt solution; then adding the carbon microsphere-hydrotalcite composite material and deionized water to the iron salt solution, ultrasonically dispersing the mixture, and then adding sodium hydroxide to adjust the pH to 10.2. The mixture was reacted in a water bath at 85° C. for 30 minutes. After the reaction, the mixture was cooled, washed, and dried to obtain a composite magnetic material; the reaction mass ratio of ferrous sulfate heptahydrate, ferric nitrate nonahydrate, and carbon microsphere-hydrotalcite composite material was 0.07:0.17:0.025; Step S4: 25 g of a composite magnetic material, 60 g of vinyl polysiloxane, 10 g of hydrogen-containing polysiloxane, 0.03 g of chloroplatinic acid, and 0.03 g of methylpentynol were mixed to obtain a composite magnetic adhesive; A shielding shell is obtained by die-casting an aluminum-magnesium alloy raw material; a composite magnetic adhesive is applied to a fixed position of the shielding cover, and the shielding cover is vulcanized at 120° C. for 40 minutes and packaged to obtain a finished product.

[0029] Comparative Example 3: The composite magnetic adhesive, the silver-copper conductive composite adhesive, and the silver-loaded conductive composite adhesive were removed, but some adhesive preparation steps were retained; the rest were the same as in Example 1, and the specific steps were as follows: Step S1: 60 g of vinyl polysiloxane, 10 g of hydrogen-containing polysiloxane, 0.03 g of chloroplatinic acid, and 0.03 g of methylpentynol were mixed to obtain an adhesive; Step S2: die-casting the aluminum-magnesium alloy raw material to obtain a shielding shell; applying adhesive at a fixed position of the shielding cover, vulcanizing at 120° C. for 40 minutes, and packaging to obtain a finished product.

[0030] Detection test: Electromagnetic shielding performance test: The adhesive prepared by the present invention was sequentially added to the mold (following the corresponding dispensing order of the embodiment / comparative example) and vulcanized to obtain a sample. The sample was a circular sample with a diameter of 12 mm and a thickness of 2 mm. The electromagnetic shielding performance of the sample was tested using a vector network analyzer at a test frequency of 12 GHz. The test data were substituted into the formula to calculate the electromagnetic absorption shielding effectiveness SE. A , electromagnetic reflection shielding effectiveness SE R , the total electromagnetic shielding effectiveness SE of the material T The results are shown in the following table: Conclusion: The dosages used in Examples 1 to 3 remained unchanged, and only some reaction parameters were modified. The experimental data show that there was no significant fluctuation in the performance of the samples.

[0031] Comparative Example 1: The silver-loaded conductive composite adhesive is removed, and the rest is the same as Example 1. It can be seen from the experimental data that compared with Example 1, the electromagnetic absorption shielding effectiveness is reduced to 40.5dB, and the electromagnetic reflection shielding effectiveness is reduced to 28.3dB. The reasons are analyzed as follows: the silver-loaded conductive composite adhesive is based on the porous conductive composite material, and the chemical reduction method is used to introduce metallic silver with excellent conductivity, which further enhances the conductivity of the material, thereby effectively improving the scattering and absorption opportunities of electromagnetic waves inside the material. Therefore, after removing it, the electromagnetic absorption shielding effectiveness is reduced and the electromagnetic reflection shielding effectiveness is reduced.

[0032] Comparative Example 2: The silver-loaded copper conductive composite adhesive and the silver-loaded conductive composite adhesive are removed, and the rest are the same as Example 1. It can be seen from the experimental data that compared with Example 1, the electromagnetic absorption shielding effectiveness is reduced to 38.5 dB, and the electromagnetic reflection shielding effectiveness is reduced to 23.7 dB. The reasons are analyzed as follows: on the basis of Comparative Example 1, Comparative Example 2 removes the silver-loaded copper conductive composite adhesive, and the silver-loaded copper conductive composite adhesive is based on the porous conductive composite material and uses a reduction method to simultaneously introduce metallic silver and copper with excellent conductivity, so it has more excellent conductive properties, which can effectively improve the scattering and absorption opportunities of electromagnetic waves inside the material. Therefore, after removing it, the electromagnetic absorption shielding effectiveness is reduced and the electromagnetic reflection shielding effectiveness is reduced.

[0033] Comparative Example 3: The composite magnetic adhesive, silver-copper conductive composite adhesive, and silver conductive composite adhesive are removed, and the rest are the same as Example 1. It can be seen from the experimental data that compared with Example 1, the electromagnetic absorption shielding effectiveness is reduced to 26.2dB, and the electromagnetic reflection shielding effectiveness is reduced to 30.1dB. The reason is analyzed as follows: on the basis of Comparative Example 2, Comparative Example 3 removes the composite magnetic adhesive, and the composite magnetic adhesive includes ferromagnetic material ferrosoferric oxide, ferromagnetic material hydrotalcite structure and conductive carbon microspheres, so an efficient electromagnetic shielding system is formed. Therefore, after removing it, the electromagnetic absorption shielding effectiveness is reduced and the electromagnetic reflection shielding effectiveness is reduced.

[0034] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include," "comprise," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0035] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a shielding cover based on silicone rubber conductive adhesive, characterized in that: The following steps are involved: The aluminum-magnesium alloy raw material is die-cast to obtain a shielding shell; a composite magnetic adhesive, a silver-copper conductive composite adhesive, and a silver-loaded conductive composite adhesive are sequentially applied to a fixed position of the shielding cover, and the product is vulcanized at 100-120°C for 30-40 minutes and packaged to obtain a finished product.

2. The method for preparing a shielding cover based on silicone rubber conductive adhesive according to claim 1, characterized in that: The method comprises mixing 20-25 parts of a composite magnetic material, 50-60 parts of vinyl polysiloxane, 8-10 parts of hydrogen-containing polysiloxane, 0.02-0.03 parts of chloroplatinic acid, and 0.02-0.03 parts of methylpentynol in parts by mass to obtain a composite magnetic adhesive; mixing 20-25 parts of a silver-copper conductive composite material, 50-60 parts of vinyl polysiloxane, 8-10 parts of hydrogen-containing polysiloxane, 0.02-0.03 parts of chloroplatinic acid, and 0.02-0.03 parts of methylpentynol in parts by mass to obtain a silver-copper conductive composite adhesive; and mixing 20-25 parts of a silver-loaded conductive composite material, 50-60 parts of vinyl polysiloxane, 8-10 parts of hydrogen-containing polysiloxane, 0.02-0.03 parts of chloroplatinic acid, and 0.02-0.03 parts of methylpentynol in parts by mass to obtain a silver-loaded conductive composite adhesive.

3. The method for preparing a shielding cover based on silicone rubber conductive adhesive according to claim 2, characterized in that: The preparation process of silver-loaded conductive composite materials and silver-loaded copper conductive composite materials is as follows: Step S1: adding polymethyl methacrylate powder to deionized water to obtain polymethyl methacrylate solution; then adding Ti3C2T X MXene powder is added to a polymethyl methacrylate solution, stirred thoroughly for 25-30 minutes, and centrifuged to obtain a composite material. The composite material and graphene oxide are then added to deionized water, stirred thoroughly for 3-4 hours under an argon atmosphere, and freeze-dried to obtain a conductive composite material. The conductive composite material is heat-treated at 440-450°C under an argon atmosphere for 1.2-1.5 hours to obtain a porous conductive composite material. Step S2: adding silver nitrate to deionized water to obtain a silver nitrate solution; then adding the porous conductive composite material, ultrasonically dispersing for 20-30 minutes, then adding ethylene glycol, and continuing ultrasonically dispersing for 15-20 minutes. After uniform dispersion, react in a water bath at 35-40° C. for 15-20 hours. After the reaction is completed, cooling, centrifuging, washing, and drying to obtain a silver-loaded conductive composite material; Step S3: adding polyvinyl alcohol to deionized water to obtain a polyvinyl alcohol solution; adding silver nitrate to deionized water to obtain a silver nitrate solution; adding copper nitrate trihydrate to deionized water to obtain a copper nitrate solution; The silver nitrate solution and the copper nitrate solution are mixed, stirred evenly, and then the porous conductive composite material is added. After ultrasonic dispersion for 20-30 minutes, the polyvinyl alcohol solution is added and ultrasonic dispersion is continued for 15-20 minutes. After uniform dispersion, the mixture is reacted in a water bath at 80-90° C. for 1.0-1.5 hours. After the reaction is completed, the mixture is cooled, centrifuged, washed, and dried to obtain a silver-copper conductive composite material.

4. The method for preparing a shielding cover based on silicone rubber conductive adhesive according to claim 3, characterized in that: In step S1, polymethyl methacrylate powder, Ti3C2T X The reaction mass ratio of MXene powder and graphene oxide is (6-7):1:(4-5).

5. The method for preparing a shielding cover based on silicone rubber conductive adhesive according to claim 3, characterized in that: In step S2, when preparing the silver-loaded conductive composite material, the mass volume ratio of silver nitrate, porous conductive composite material, and ethylene glycol is (0.35-0.40) g:2.5 g:20 mL.

6. The method for preparing a shielding cover based on silicone rubber conductive adhesive according to claim 3, characterized in that: In step S3, the reaction mass ratio of silver nitrate, copper nitrate trihydrate, porous conductive composite material, and polyvinyl alcohol is 0.15:(0.075-0.078):1.8:7.

5.

7. The method for preparing a shielding cover based on silicone rubber conductive adhesive according to claim 2, characterized in that: The preparation process of composite magnetic materials is as follows: Step S1: adding xylose to deionized water to obtain a 0.45-0.50 mol / L xylose solution; The xylose solution is heat-treated at 180-200°C for 11-13 hours, and after the reaction is completed, it is cooled, filtered, washed, and dried to obtain carbon microspheres; Step S2: adding carbon microspheres to deionized water, and adding sodium hydroxide to adjust the pH to 11.0-11.2 to obtain a carbon microsphere solution; Nickel nitrate hexahydrate and ferric nitrate nonahydrate are added to deionized water to obtain a salt solution; the salt solution is added dropwise to the carbon microsphere solution, and urea and ammonium fluoride are added after the addition is completed. After ultrasonic dispersion, the mixture is reacted at 110-120° C. for 11-13 hours. After the reaction is completed, the mixture is cooled, washed, and dried to obtain a carbon microsphere-hydrotalcite composite material; Step S3: adding ferrous sulfate heptahydrate and ferric nitrate nonahydrate to deionized water and stirring thoroughly to obtain an iron salt solution; then adding the carbon microsphere-hydrotalcite composite material and deionized water to the iron salt solution, ultrasonically dispersing the mixture uniformly, adding sodium hydroxide to adjust the pH to 10.0-10.2, and reacting in a water bath at 80-85° C. for 20-30 minutes. After the reaction is completed, the mixture is cooled, washed, and dried to obtain a composite magnetic material.

8. The method for preparing a shielding cover based on silicone rubber conductive adhesive according to claim 7, characterized in that: In step S2, the reaction mass ratio of carbon microspheres, nickel nitrate hexahydrate, ferric nitrate nonahydrate, urea, and ammonium fluoride is (0.08-0.1): 0.22: 0.1: 0.35: 0.

08.

9. The method for preparing a shielding cover based on silicone rubber conductive adhesive according to claim 7, characterized in that: In step S3, the reaction mass ratio of ferrous sulfate heptahydrate, ferric nitrate nonahydrate, and carbon microsphere-hydrotalcite composite material is 0.07:0.17:(0.02-0.03).

10. A shielding cover based on silicone rubber conductive adhesive, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 9.

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