Electromagnetic wave shielding element, formulation, preparation method and electromagnetic wave shielding device

Abstract

The present application provides an electromagnetic wave shielding element, a formulation, a preparation method, and an electromagnetic wave shielding device. The electromagnetic wave shielding element comprises a liquid silicone rubber substrate. The liquid silicone rubber substrate can be processed into a preset shape according to requirements. Core-shell structured conductive powder and a microsphere core-shell structure are mixed in the liquid silicone rubber substrate. The shell of the microsphere core-shell structure is made of an elastic material. The microsphere core-shell structure is filled with a displacement medium. A sealed cavity is formed in the microsphere core-shell structure when the displacement medium is heated. The microsphere core-shell structure displaces part of the liquid silicone rubber substrate in the liquid silicone rubber substrate, so as to reduce the weight of the electromagnetic wave shielding element. Additionally, the core-shell structured conductive powder is used for shielding electromagnetic waves, and the microsphere core-shell structure is used for changing the impedance of the electromagnetic wave shielding element, so that the electromagnetic wave shielding element has an electromagnetic wave shielding function and can also absorb electromagnetic waves.

Description

Electromagnetic wave shielding elements, formulations, preparation methods, and electromagnetic wave shielding equipment Technical Field

[0001] This application belongs to the field of electromagnetic shielding and sealing technology, and more specifically, relates to an electromagnetic wave shielding element, formula, preparation method and electromagnetic wave shielding equipment. Background Technology

[0002] With the rapid development of modern technology, the demand for electromagnetic shielding technology is constantly increasing in fields such as intelligent driving vehicles, national defense and military industries, high-speed communication base stations, and data centers. In these applications, electromagnetic interference (EMI) has become one of the key factors restricting equipment stability and performance. Therefore, how to effectively solve the electromagnetic interference problem and ensure the normal operation of equipment, especially in high-frequency and high-power environments, has become the focus of current technological research and engineering applications. Technical issues

[0003] In electronic devices, PCBA (Printed Circuit Board Assembly) is the most basic unit for electromagnetic interference (EMI) protection. The electromagnetic shielding at the PCBA level not only affects the stability of individual components but also determines the electromagnetic compatibility (EMC) of the entire device.

[0004] Traditional electromagnetic shielding technologies typically rely on the use of conductive materials, such as conductive metal shielding covers, conductive coatings, and shielding strips. While these materials can effectively isolate electromagnetic waves, their solid structures often result in high density, weight, and cost. They also struggle to meet performance requirements in extreme environments such as high and low temperatures, and their elasticity needs improvement. Furthermore, as shown in Figure 1, traditional shielding materials are filled only with core-shell structured conductive powder. Therefore, these materials only provide electromagnetic shielding and lack wave absorption capabilities, failing to effectively reduce electromagnetic wave reflection and resulting in unsatisfactory shielding performance. Technical solutions

[0005] The purpose of this application is to provide an electromagnetic wave shielding element, a formula, a preparation method, and an electromagnetic wave shielding device to solve the technical problems existing in the prior art.

[0006] To achieve the above objectives, a first aspect of this application is to provide an electromagnetic wave shielding element, comprising:

[0007] Liquid silicone substrates can be processed into preset shapes;

[0008] Core-shell structured conductive powder is mixed in the liquid silicone substrate and uniformly distributed within the liquid silicone substrate 10;

[0009] The microsphere shell-core structure is mixed in the liquid silica substrate and uniformly distributed within the liquid silica substrate to replace a portion of the liquid silica substrate within the liquid silica substrate;

[0010] The microsphere shell-core structure includes an outer shell and a displacement medium filled inside the outer shell. The displacement medium is used to form the core structure of the microsphere shell-core structure. The outer shell is made of an elastic material. The displacement medium is used to vaporize at high temperature and place air inside the outer shell to form a sealed cavity inside the outer shell.

[0011] The core-shell structure conductive powder is used to shield electromagnetic waves, and the microsphere core-shell structure is used to change the impedance of the electromagnetic wave shielding element.

[0012] Optionally,

[0013] The outer shell is made of polymethyl methacrylate.

[0014] Optionally, the replacement medium is any one of n-hexane, ethyl acetate, chloroform, and dichloromethane.

[0015] Optionally, the diameter of the cavity is less than or equal to 0.3 times the wavelength of the target electromagnetic wave.

[0016] Optionally, the diameter of the outer casing is less than or equal to 40 micrometers.

[0017] Optionally, the preset shape is a sheet or a strip.

[0018] Optionally, when the preset shape is a strip, the cross-sectional shape of the preset shape can be any one of a trapezoid, an n-shape, a D-shape, or a triangle.

[0019] Optionally, it is characterized in that,

[0020] The density of the electromagnetic wave shielding element is between 1.3 and 1.8 g / cm³. 3 .

[0021] Optionally, the compression ratio of the electromagnetic wave shielding element is between 10% and 60%.

[0022] Compared with the prior art, the electromagnetic wave shielding element provided in this application, by filling a liquid silicone substrate with a microsphere core structure to replace part of the liquid silicone substrate, and by making the outer shell of the microsphere core structure into an elastic material, and by forming a sealed cavity inside it after heating, has the following advantages:

[0023] 1. After the microsphere core-shell structure is filled into a liquid silica substrate, the formation of a sealed cavity within it upon heating reduces the density of the electromagnetic wave shielding element. Compared to existing technologies, the density of this electromagnetic wave shielding element is 1.3–1.8 g / cm³. 3 This reduces the mass of the electromagnetic wave shielding element, making it easier to make electronic products using the electromagnetic wave shielding element lighter.

[0024] 2. After the microsphere shell-core structure is filled into the liquid silicone substrate, it does not affect the mutual distribution between the conductive powder particles. Furthermore, because the outer shell of the microsphere shell-core structure is made of an elastic material and a sealed cavity is formed inside after heating, the electromagnetic wave shielding element is easier to compress. After compression, it is easier for conductive powders in the shell-core structure to form conductive contacts, thereby improving the conductivity of the electromagnetic wave shielding element and reducing its resistance, thus improving the shielding performance against electromagnetic waves. At the same time, after the electromagnetic wave shielding element is compressed, its internal compressive stress is lower than that of electromagnetic wave shielding elements in the prior art, thus making the electromagnetic wave shielding element suitable for use in automotive electronic components where low compressive stress is required.

[0025] 3. Since both the liquid silicone substrate and the outer shell of the microsphere core structure are elastic after curing, the electromagnetic wave shielding element still has good resilience when the compression rate of the electromagnetic wave shielding element is between 10% and 60% after the liquid silicone substrate is cured and formed. This makes the electromagnetic wave shielding element less prone to permanent deformation, thus making it less likely to crack and short circuit.

[0026] 4. Since both the liquid silicone substrate and the outer shell of the microsphere core structure are elastic after curing, the electromagnetic wave shielding element is elastic after the liquid silicone substrate is cured and formed. After the electromagnetic wave shielding element has undergone multiple cycles of high and low temperature environments, it can still maintain good isolation performance against electromagnetic waves.

[0027] 5. Since the microsphere shell core structure forms a closed cavity after heating, the impedance of the electromagnetic wave shielding element is changed after the microsphere shell core structure is filled into the liquid silicone substrate, thereby giving the electromagnetic wave shielding element the function of absorbing electromagnetic waves.

[0028] 6. Because the microsphere shell core structure forms a sealed cavity inside after heating, compared with the existing open foam structure, liquids and gases cannot penetrate the electromagnetic wave shielding element, making the electromagnetic wave shielding element more widely applicable. In addition, the sealed cavity inside the microsphere shell core structure has a certain volume, and the microsphere shell core structure is made of elastic material, so the diameter of the microsphere shell core structure can be adjusted by heating. Furthermore, because there is gas inside the cavity, the shape of the microsphere shell core structure is well restored after being compressed, so that the appearance of the electromagnetic wave shielding element will not be significantly deformed.

[0029] Secondly, this application provides an electromagnetic wave shielding device, comprising:

[0030] An electromagnetic wave shielding element, wherein the electromagnetic wave shielding element is any one of the electromagnetic wave shielding elements described above.

[0031] Compared with the prior art, the electromagnetic wave shielding device provided in this application includes the electromagnetic wave shielding element provided by any of the above-mentioned items, and its beneficial effects are the same as those of the electromagnetic wave shielding element mentioned above, which will not be described in detail here.

[0032] Thirdly, this application provides a formulation for an electromagnetic wave shielding element, comprising the following components:

[0033] 40-80 parts of core-shell structured conductive powder;

[0034] Antioxidant 2-5 parts;

[0035] Anti-sulfurization agent 1-10 parts;

[0036] 15-50 parts of liquid silica gel;

[0037] 1-10 parts of platinum catalyst solution;

[0038] 5-20 parts of decanyltrimethoxysilane;

[0039] 0.5–3 parts of the microsphere shell-core structure.

[0040] Compared with the prior art, the formulation of the electromagnetic wave shielding element provided in this application, when used to produce the electromagnetic wave shielding element provided in any of the above-mentioned methods, has the same beneficial effects as the electromagnetic wave shielding element described above, and will not be repeated here.

[0041] Fourthly, this application provides a method for preparing an electromagnetic wave shielding element, used to prepare the electromagnetic wave shielding element provided in any of the above-mentioned methods, comprising the following steps:

[0042] S1, Prepare liquid electromagnetic wave shielding components;

[0043] S2, the electromagnetic wave shielding element of the liquid is processed into a preset shape;

[0044] S3, magnetize the core-shell structure conductive powder inside the electromagnetic wave shielding element;

[0045] S4, the liquid electromagnetic wave shielding element is cured at high temperature, and the displacement medium in the microsphere shell-core structure inside the electromagnetic wave shielding element is vaporized, and the liquid electromagnetic wave shielding element is formed into an elastic and solid electromagnetic wave shielding element.

[0046] Optionally, step S1 specifically includes:

[0047] S1.1 After stirring and preheating the core-shell structure conductive powder, add antioxidants and anti-sulfurization agents, continue stirring, and then cool;

[0048] S1.2, the platinum catalyst solution and decantrimethoxysilane are mixed into liquid silica gel, and the mixture is stirred in stages while controlling the stirring temperature;

[0049] S1.3, the microsphere shell-core structure is mixed into the liquid silica substrate and stirred in stages while controlling the stirring temperature to obtain an initial mixture;

[0050] S1.4, The core-shell structure conductive powder is mixed into the initial mixture and stirred, and the stirring temperature is controlled to obtain the electromagnetic wave shielding element in the state described above.

[0051] Optionally, step S1.1 specifically includes:

[0052] S1.1.1, the core-shell structure conductive powder is stirred and preheated, wherein the stirring speed is 15 rpm, the stirring temperature is between 50 and 80 degrees Celsius, and the stirring time is between 3 and 6 minutes;

[0053] S1.1.2 After completing step S1.1.2, the antioxidant and anti-sulfurization agent are added to the core-shell structure conductive powder and stirred, wherein the rotation speed is 30 rpm and the stirring time is 10-20 minutes;

[0054] S1.1.3 After completing step S1.1.2, cool to room temperature.

[0055] Optionally, in step S1.2, the segmented stirring specifically includes:

[0056] S1.2.1, First stirring stage: 10 revolutions per minute, stirring time is 3 minutes;

[0057] S1.2.2, Second mixing stage: 15 rpm, mixing time is 10 minutes;

[0058] S1.2.3, Third mixing stage: 30 rpm, mixing time is 5 minutes;

[0059] S1.2.4, Fourth mixing stage: 10 rpm, mixing time is 2 minutes;

[0060] In step S1.2, the stirring temperature is between 30 and 40 degrees Celsius.

[0061] Optionally, in step S1.3, the segmented stirring specifically includes:

[0062] S1.3.1, the fifth mixing stage, the mixing speed is 15 rpm, and the mixing time is 5 minutes;

[0063] S1.3.2, the sixth mixing stage, the mixing speed is 40 rpm, and the mixing time is 15 minutes;

[0064] S1.3.3, the seventh mixing stage, the mixing speed is 30 rpm, and the mixing time is 5 minutes;

[0065] In step S1.3, the shear temperature during stirring is less than or equal to 60 degrees Celsius.

[0066] Optionally, in step S2:

[0067] The liquid electromagnetic wave shielding element is processed into the preset shape using any one of the following molding methods: injection molding, coating molding, compression molding, extrusion molding, or dispensing molding.

[0068] Optionally, in step S3:

[0069] The core-shell conductive powder structure is magnetized by magnetic forming or magnetic shaping.

[0070] Specifically, when magnetizing the core-shell structure conductive powder, the magnetic flux is between 100 and 2500 Gauss, and the magnetization time is between 1 and 15 seconds.

[0071] Optionally, in step S4:

[0072] The high-temperature curing temperature is 130–200 degrees Celsius;

[0073] The high-temperature curing time is 10 to 40 minutes.

[0074] Compared with the prior art, the method for preparing the electromagnetic wave shielding element provided in this application is used to prepare the electromagnetic wave shielding element provided in any of the above-mentioned methods, and its beneficial effects are the same as those of the electromagnetic wave shielding element, which will not be elaborated here. Attached Figure Description

[0075] To more clearly illustrate the technical solutions in the embodiments of this application, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0076] Figure 1 is a schematic diagram of the internal structure of an electromagnetic wave shielding element in the prior art;

[0077] Figure 2 is a schematic diagram of the internal structure of the electromagnetic wave shielding element provided in the embodiment of this application;

[0078] Figure 3 is a schematic diagram of the internal structure of the electromagnetic wave shielding element provided in the embodiment of this application after being magnetized;

[0079] Figure 4 is a cross-sectional view of the microsphere shell-core structure provided in the embodiment of this application;

[0080] Figure 5 is a schematic diagram of the cavity in the microsphere shell-core structure provided in the embodiment of this application;

[0081] Figure 6 is a cross-sectional view of an electromagnetic wave shielding element provided in an embodiment of this application;

[0082] Figure 7 is a cross-sectional view of an electromagnetic wave shielding element provided in another embodiment of this application;

[0083] Figure 8 is a cross-sectional view of an electromagnetic wave shielding element provided in another embodiment of this application;

[0084] Figure 9 is a graph showing the relationship between the diameter of the microsphere shell-core structure in this application and temperature.

[0085] Figure 10 is a graph showing the relationship between the compression ratio of the electromagnetic wave shielding element and the electromagnetic wave shielding ratio in this application.

[0086] The following are the labeling elements in the figure:

[0087] 10. Liquid silica gel substrate; 20. Core-shell structure conductive powder; 30. Microsphere core-shell structure; 31. Outer shell; 32. Displacement medium; 33. Cavity. Embodiments of the present invention

[0088] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0089] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0090] Please refer to Figures 1 to 10 together. The electromagnetic wave shielding element, formula, preparation method and electromagnetic wave shielding device provided in the embodiments of this application will now be described.

[0091] To achieve the above objectives, a first aspect of this application is to provide an electromagnetic wave shielding element, comprising a liquid silicone substrate 10, a core-shell structure conductive powder 20, and a microsphere core-shell structure 30.

[0092] The liquid silicone substrate 10 can be processed into a preset shape by any of the following molding methods: injection molding, coating molding, compression molding, extrusion molding, or dispensing molding. After being processed into the preset shape, the liquid silicone substrate 10 is placed in a preset position, such as in a gap in an electromagnetic shielding device, or between the opening and the cover of the shielding box in the electromagnetic device.

[0093] Please refer to Figures 2 and 3. The core-shell structure conductive powder 20 is mixed in the silicone substrate and uniformly distributed in the silicone substrate. The core-shell structure conductive powder 20 is a particulate material with conductivity and ferromagnetism.

[0094] When the core-shell conductive powder 20 is formed or shaped by magnetic force, and a magnetic field is applied to the liquid silicone substrate 10, the core-shell conductive powder 20 is ferromagnetic. Under the influence of the magnetic field, the core-shell conductive powder 20 is oriented in the same direction as the magnetic field. For example, the core-shell conductive powder 20 is arranged along the direction of the magnetic field. After the liquid silicone substrate 10 is processed into a preset shape, the core-shell conductive powder 20 contacts each other to conduct electricity, thereby providing electromagnetic shielding for electromagnetic waves.

[0095] Meanwhile, since the core-shell structure conductive powder 20 is ferromagnetic and can be affected by a magnetic field, the strength and duration of the magnetic field can be adjusted as needed to orient the core-shell structure conductive powder 20 in the liquid silicone substrate 10 and adapt it to different preset shapes.

[0096] When processing the liquid electromagnetic wave shielding element into a preset shape as needed, the liquid silicone substrate 10 can be cured by heating so that the electromagnetic wave shielding element is kept in the preset shape.

[0097] The microsphere shell-core structure 30 is mixed in the liquid silicone substrate 10 and uniformly distributed within the liquid silicone substrate 10, thereby displacing part of the liquid silicone substrate 10.

[0098] The microsphere shell-core structure 30 includes an outer shell 31 and a displacement medium 32 filled inside the outer shell 31. The displacement medium 32 is used to form the core structure of the microsphere shell-core structure 30. The outer shell 31 is made of an elastic material. The displacement medium 32 is used to vaporize at high temperature and place air inside the outer shell 31 to form a sealed cavity 33 inside the outer shell 31.

[0099] It should be noted that the displacement medium 32 is made of a low-boiling-point material. When the liquid silicone substrate 10 is solidified into a preset shape by heating, the displacement medium 32 vaporizes at high temperature and displaces air into the interior of the outer shell 31 to form a sealed cavity inside the outer shell 31.

[0100] Please refer to Figures 4, 5, and 9. Initially, the diameter of the outer shell 31 is set to D1, and the diameter of the core structure formed by the replacement medium 32 is set to D2. When the liquid silicone substrate 10 is solidified into a preset shape by heating, the replacement medium 32 is heated and vaporized, and air is replaced into the outer shell 31 to form a cavity 33 with a diameter of D2', where D2' is larger than D2. Since the outer shell 31 is made of an elastic material, the diameter of the outer shell 31 increases from D1 to D1', and the wall thickness of the outer shell 31 becomes thinner. Therefore, the diameter of the microsphere core structure 30 and the diameter of its internal cavity 33 can be adjusted by adjusting the temperature.

[0101] In Figure 9, the bottom curve represents the change in diameter of the microsphere shell-core structure 30 at different temperatures when the initial diameter is 5 micrometers; the middle curve represents the change in diameter of the microsphere shell-core structure 30 at different temperatures when the initial diameter is 15 micrometers; and the top curve represents the change in diameter of the microsphere shell-core structure 30 at different temperatures when the initial diameter is 20 micrometers.

[0102] As shown in Figure 9, the diameter of the microsphere shell-core structure 30 gradually increases with increasing temperature, and the rate of increase in the diameter of the microsphere shell-core structure 30 gradually slows down. Therefore, the diameter of the microsphere shell-core structure 30 and the diameter of its internal cavity 33 can be adjusted by adjusting the temperature.

[0103] When electromagnetic waves pass through the microsphere shell core structure 30 with cavity 33, the electromagnetic waves are reflected on the surface of the microsphere shell core structure 30. The electromagnetic waves are reflected and return to the surface of the microsphere shell core structure 30, resulting in increased energy loss of the electromagnetic waves. Moreover, the propagation path of the electromagnetic waves inside the cavity 33 is deflected, causing some electromagnetic energy to be reflected from the original direction, while the other part is scattered in other directions by the inner wall of the cavity 33. This scattering reduces the energy of the electromagnetic waves, thereby changing the impedance of the electromagnetic waves when they pass through the microsphere shell core structure 30. This change in impedance causes the electromagnetic waves to pass through the electromagnetic wave shielding element, thus absorbing the electromagnetic waves.

[0104] In this application, the core-shell structure conductive powder 20 is at least one of the following: a nickel-carbon structure with a carbon interior and a nickel outer layer, a silver-carbon structure with a carbon interior and a silver outer layer, a silver-glass structure with a glass interior and a silver outer layer, and a silver-aluminum structure with an aluminum interior and a silver outer layer.

[0105] Specifically, in this application, the outer shell 31 is made of polymethyl methacrylate. The replacement medium 32 is any one of n-hexane, ethyl acetate, chloroform, and dichloromethane.

[0106] During the high-temperature curing stage of the electromagnetic wave element, the displacement medium 32 is heated and vaporized under high temperature, and air is displaced into the cavity 33.

[0107] In this application, the diameter of cavity 33 is less than or equal to 0.3 times the wavelength of the target electromagnetic wave.

[0108] When the diameter of the sealed cavity 33 is less than 0.3 times the wavelength of the target electromagnetic wave, the target electromagnetic wave usually cannot effectively penetrate the cavity 33. This is because when the wavelength of the electromagnetic wave is larger than the size of the cavity 33, the electromagnetic wave will be reflected and diffracted within the cavity 33, preventing it from penetrating. In particular, when the size of the cavity 33 is less than a certain proportion of the wavelength, such as 0.3 times, the electromagnetic wave will be significantly attenuated.

[0109] Taking a 79GHz electromagnetic wave as an example, its wavelength is 3.8 mm. When the diameter of the cavity 33 is less than the target 0.3*3.8=0.114 mm, the 79GHz electromagnetic wave cannot penetrate into the sealed cavity 33 with a diameter of less than or equal to 0.114 mm, thus enabling the electromagnetic wave shielding element to absorb electromagnetic waves.

[0110] When the electromagnetic wave shielding element is set in a preset position, it will be compressed by the components on both sides of it. At this time, the compression rate of the electromagnetic wave shielding element is 10% to 20%. After the electromagnetic wave shielding element is compressed, the diameter of the cavity 33 is less than 0.3 times the wavelength of the target electromagnetic wave, which further prevents the electromagnetic wave from penetrating the cavity 33.

[0111] In one embodiment of this application, the diameter of the outer casing 31 is less than or equal to 40 micrometers.

[0112] Since the cavity 33 is located inside the outer shell 31 and its diameter is smaller than that of the outer shell 31, when the diameter of the outer shell 31 is less than or equal to 40 micrometers, the diameter of the cavity 33 inside it is much smaller than 40 micrometers. When electromagnetic waves of various wavelengths pass through the micropore, they can be diffracted in the cavity 33, causing them to be unable to penetrate. Thus, the electromagnetic wave shielding element can absorb electromagnetic waves of various wavelengths.

[0113] In this application, since the silicone substrate is liquid, the liquid silicone substrate 10 can be formed into sheets or strips by any of the molding methods such as injection molding, coating molding, compression molding, extrusion molding or dispensing molding, as needed.

[0114] When the liquid silicone substrate 10 is made into a sheet structure, its shape can be made into the required shape, such as a triangle, rectangle, or circle. When the liquid silicone substrate 10 is made into a strip structure, its shape can be a long strip structure, a ring structure, or a shape adapted to the application environment as needed.

[0115] In this application, please refer to Figures 6 to 8. When the preset shape is strip-shaped, the cross-sectional shape of the preset shape is any one of trapezoid, n-shape, D-shape or triangle, or it can be processed into a shape that is suitable for the place of use as needed.

[0116] In this application, since a microsphere core structure 30 with 33 is filled into the liquid silicone substrate 10, the density of the electromagnetic wave shielding element can be made to be between 1.3 and 1.8 g / cm³ by adjusting the proportion of the microsphere core structure 30 in the liquid silicone substrate 10. When the microsphere core structure 30 is filled into the liquid silicone substrate 10 at its maximum proportion, the density of the electromagnetic wave shielding element is 1.4 g / cm³ because more of the silicone substrate in the liquid silicone substrate 10 is replaced by cavities 33. When the microsphere core structure 30 is filled into the liquid silicone substrate 10 at its minimum proportion, the density of the electromagnetic wave shielding element is 1.75 g / cm³.

[0117] Compared to existing electromagnetic wave shielding elements that do not have a microsphere shell core structure 30 inside, the electromagnetic wave shielding element provided in this application that has a microsphere shell core structure 30 inside has a lower mass, so that electronic products using this electromagnetic wave shielding element can achieve lightweighting.

[0118] In this application, the compression ratio of the electromagnetic wave shielding element is between 10% and 60%.

[0119] In this application, since the liquid silicone substrate 10 is elastic after curing, and the microsphere shell core structure 30 is also made of elastic material, the electromagnetic wave shielding element can be compressed after the liquid silicone substrate 10 is cured into a preset shape.

[0120] When the volume of the electromagnetic wave shielding element is compressed, it is easier for conductive contacts to form between the conductive powders 20 in its core-shell structure, thus improving the shielding effect. Simultaneously, the diameter of the microsphere core-shell structure 30 and the volume of its internal cavity 33 are also compressed. Taking a 10% compression of the electromagnetic wave shielding element's volume as an example, where the diameter of the microsphere core-shell structure 30 and the volume of its internal cavity 33 are also compressed by 10%, the diameter of the microsphere core-shell structure 30 becomes 40*(1-10%)=36 micrometers. Furthermore, the diameter of the cavity 33 inside the microsphere core-shell structure 30 is further compressed, further enhancing the shielding element's ability to absorb electromagnetic waves of various wavelengths.

[0121] Table 1: Compressive stress inside electromagnetic wave shielding elements of different sizes under different compression ranges when the core-shell structure conductive powder 20 is nickel-carbon structure in this application;

[0122]

[0123] Table 2: Compressive stress inside electromagnetic wave shielding elements of different sizes at different compression ranges when the core-shell structure conductive powder 20 is a nickel-carbon structure in the prior art;

[0124]

[0125] As shown in Tables 1 and 2, compared with the prior art electromagnetic wave shielding element where only the core-shell structure conductive powder 20 is filled in the silicone substrate, the electromagnetic wave shielding element provided in this application has lower internal compressive stress at different compression levels for different sizes than the electromagnetic wave shielding element of the same size and compression level in the prior art. Since the lower the internal compressive stress at different compression levels, the stronger the deformation ability and the higher the plasticity of the electromagnetic wave shielding element, and the better its toughness and ductility, the electromagnetic wave shielding element provided in this application has better deformation ability, plasticity, toughness and ductility than the electromagnetic wave shielding element in the prior art. Therefore, the electromagnetic wave shielding element provided in this application can adapt to greater stress and is not easy to break.

[0126] Table 3: Internal resistance of electromagnetic wave shielding elements of different sizes under different compression ranges when the core-shell structure conductive powder 20 is nickel-carbon structure in this application;

[0127]

[0128] As shown in Table 3, for the same size, the resistance of the electromagnetic wave shielding element proposed in this application decreases with the increase of compression ratio. After compression, the electromagnetic wave shielding element facilitates the formation of conductive contacts between the core-shell structure conductive powders 20, thereby improving the conductivity of the electromagnetic wave shielding element and enhancing its shielding performance against electromagnetic waves.

[0129] It should be noted that when the core-shell structure conductive powder 20 has a silver-copper, silver-nickel, or silver-aluminum structure, its resistance value will be less than that when the core-shell structure conductive powder 20 has a nickel-carbon structure.

[0130] Please refer to Figure 10. In Figure 10, taking the core-shell structure conductive powder 20 as an example with a nickel-carbon structure and a diameter of 1.6 mm, the vertical axis represents SE (Shielding Effectiveness), and the horizontal axis represents the compression ratio of the electromagnetic wave shielding element. As shown in Figure 10, under the same size, the electromagnetic shielding effectiveness of the electromagnetic wave shielding element gradually increases with the increase of the compression ratio.

[0131] Compared with the prior art, the electromagnetic wave shielding element provided in this application, by filling the liquid silicone substrate 10 with a microsphere shell core structure 30, replacing part of the liquid silicone substrate 10, and making the outer shell 31 of the microsphere shell core structure 30 made of an elastic material, and forming a sealed cavity 33 inside it after heating, has the following advantages:

[0132] 1. After the microsphere shell-core structure 30 is filled into the liquid silicone substrate 10, the density of the electromagnetic wave shielding element is reduced because a closed cavity 33 is formed inside it after heating. Compared with the prior art, the density of the electromagnetic wave shielding element is 1.3 to 1.8 g / cm, thereby reducing the mass of the electromagnetic wave shielding element, so as to make the electronic products using the electromagnetic wave shielding element lighter.

[0133] 2. After the microsphere shell-core structure 30 is filled into the liquid silicone substrate 10, it does not affect the mutual distribution between the conductive powder particles of the shell-core structure 20. Furthermore, since the outer shell 31 of the microsphere shell-core structure 30 is made of an elastic material and a sealed cavity 33 is formed inside after heating, the electromagnetic wave shielding element is easier to compress. After compression, it is easier for conductive contacts to be formed between the shell-core structure conductive powder 20, thereby improving the conductivity of the electromagnetic wave shielding element and reducing its resistance, thus improving the shielding performance of electromagnetic waves. At the same time, after the electromagnetic wave shielding element is compressed, its internal compressive stress is lower than that of electromagnetic wave shielding elements in the prior art, thus making the electromagnetic wave shielding element suitable for use in automotive electronic components where low compressive stress is required.

[0134] 3. Since both the liquid silicone substrate 10 and the outer shell 31 of the microsphere core structure 30 are elastic after curing, the liquid silicone substrate 10 has low density and low compressive stress. When the compression rate of the electromagnetic wave shielding element is between 10% and 60%, the electromagnetic wave shielding element still has good resilience, which makes it difficult for the electromagnetic wave shielding element to undergo permanent deformation, and thus makes it less likely for the electromagnetic wave shielding element to crack and short circuit.

[0135] 4. Since both the electromagnetic wave shielding electronic component of the liquid silicone substrate 10 and the outer shell 31 of the microsphere shell core structure 30 are elastic, the electromagnetic wave shielding element is elastic after the liquid silicone substrate 10 is cured and formed. After the electromagnetic wave shielding element has undergone multiple cycles of high and low temperature environments, the electromagnetic wave shielding element can still maintain good isolation performance against electromagnetic waves.

[0136] 5. Since the microsphere shell-core structure 30 forms a closed cavity 33 inside after heating, the impedance of the electromagnetic wave shielding element is changed after the microsphere is filled into the liquid silicone substrate 10, so that the electromagnetic wave shielding element also has the function of absorbing electromagnetic waves.

[0137] 6. Because the microsphere shell core structure 30 forms a sealed cavity 33 inside after heating, compared with the existing open foam structure, liquid and gas will not penetrate the electromagnetic wave shielding element, making the electromagnetic wave shielding element more widely applicable. In addition, the sealed cavity 33 inside the microsphere shell core structure 30 has a certain volume, and the outer shell 31 of the microsphere shell core structure 30 is made of elastic material, so the diameter of the microsphere shell core structure 30 can be adjusted by heating. Furthermore, because there is gas inside the cavity 33, the shape of the microsphere shell core structure 30 is well restored after being compressed, so that the appearance of the electromagnetic wave shielding element will not be significantly deformed.

[0138] Secondly, this application provides an electromagnetic wave shielding device, including an electromagnetic wave shielding element, wherein the electromagnetic wave shielding element is the electromagnetic wave shielding element provided in any of the above embodiments.

[0139] The electromagnetic wave shielding element is placed at the gap of the electromagnetic wave shielding device to perform electromagnetic shielding and absorption of electromagnetic waves at the gap, thereby improving the shielding effect of the electromagnetic wave shielding device.

[0140] It should be noted that this electromagnetic shielding device can be used to shield electromagnetic waves from various communication base stations, mobile phones, or controllers in intelligent vehicle driving control systems.

[0141] Compared with the prior art, the electromagnetic wave shielding device provided in this application includes the electromagnetic wave shielding element provided by any of the above-mentioned items, and its beneficial effects are the same as those of the electromagnetic wave shielding element mentioned above, which will not be described in detail here.

[0142] Thirdly, this application provides a formulation for an electromagnetic wave shielding element, comprising the following components:

[0143] 40-80 parts of core-shell structured conductive powder;

[0144] Antioxidant 2-5 parts;

[0145] Anti-sulfurization agent 1-10 parts;

[0146] 15-50 parts of liquid silica gel;

[0147] 1-10 parts of platinum catalyst solution;

[0148] 5-20 parts of decanyltrimethoxysilane;

[0149] 0.5–3 parts of the microsphere shell-core structure.

[0150] Compared with the prior art, the formulation of the electromagnetic wave shielding element provided in this application, when used to produce the electromagnetic wave shielding element provided in any of the above-mentioned methods, has the same beneficial effects as the electromagnetic wave shielding element described above, and will not be repeated here.

[0151] In this application, antioxidants and anti-sulfurization agents are added to the core-shell structure conductive powder 20, heated and stirred until homogeneous, and then cooled to room temperature for later use. Platinum catalyst solution and decantrimethoxysilane are mixed into liquid silica gel and stirred until homogeneous, then added to the microsphere core-shell structure 30 and stirred to obtain an initial mixture. Subsequently, the core-shell structure conductive powder 20 mixed with antioxidants and anti-sulfurization agents is stirred and mixed with the initial mixture to obtain a liquid electromagnetic wave shielding element.

[0152] After the liquid silicone substrate 10 is processed into a preset shape by any of the molding methods such as injection molding, coating molding, compression molding, extrusion molding or dispensing molding, the core-shell structure conductive powder 20 in the liquid electromagnetic wave shielding element is magnetized by magnetic molding or magnetic plasticizing, and the core-shell structure conductive powder 20 is brought into contact with each other to form conductivity and electromagnetic shielding of electromagnetic waves. Then, the liquid electromagnetic wave shielding element is cured and shaped at high temperature so that the electromagnetic wave shielding element is maintained in the preset shape.

[0153] In one embodiment of this application, the electromagnetic wave shielding element comprises, by composition, 40 parts of core-shell structure conductive powder, 2 parts of antioxidant, 1 part of anti-sulfurization agent, 15 parts of liquid silica gel, 1 part of platinum catalyst solution, 5 parts of decanyltrimethoxysilane, and 0.5 parts of microsphere core-shell structure.

[0154] In another embodiment of this application, the electromagnetic wave shielding element comprises, by composition, 80 parts of core-shell structure conductive powder, 5 parts of antioxidant, 10 parts of anti-sulfurization agent, 50 parts of liquid silica gel, 10 parts of platinum catalyst solution, 20 parts of decanyltrimethoxysilane, and 3 parts of microsphere core-shell structure.

[0155] Fourthly, this application provides a method for preparing an electromagnetic wave shielding element, used to prepare the electromagnetic wave shielding element provided in any of the above embodiments, comprising the following steps:

[0156] S1, Prepare liquid electromagnetic wave shielding components;

[0157] S2, The electromagnetic wave shielding element of the liquid is processed into a preset shape;

[0158] S3, magnetize the core-shell structure conductive powder 20 inside the electromagnetic wave shielding element;

[0159] S4, the liquid electromagnetic wave shielding element is cured at high temperature, and the displacement medium 32 in the microsphere shell core structure 30 inside the electromagnetic wave shielding element is vaporized, and the liquid electromagnetic wave shielding element is formed into an elastic and solid electromagnetic wave shielding element.

[0160] Specifically, in this application, step S1 includes:

[0161] S1.1 After stirring and preheating the core-shell structure conductive powder 20, add antioxidant and anti-sulfurization agent, continue stirring, cool to room temperature, and store in a dry environment for later use;

[0162] S1.2, the platinum catalyst solution and decantrimethoxysilane are mixed into liquid silica gel, and the mixture is stirred in stages while controlling the stirring temperature;

[0163] S1.3, the microsphere shell-core structure 30 is mixed into the liquid silica substrate 10 and stirred in stages while controlling the stirring temperature to obtain an initial mixture;

[0164] S1.4, mix the core-shell structure conductive powder 20 into the initial mixture and stir, and control the stirring temperature to obtain an electromagnetic wave shielding element.

[0165] It should be noted that steps S1.1 and S1.2 can be performed simultaneously to improve production efficiency, and the device used to achieve the stirring function in the above steps is a planetary dispersion stirring device.

[0166] Specifically, in this application, step S1.1 includes:

[0167] S1.1.1, Stir and preheat the core-shell structure conductive powder 20, wherein the stirring speed is 15 rpm, the stirring temperature is 50-80 degrees Celsius, and the stirring time is 3-6 minutes;

[0168] S1.1.2 After completing step S1.1.2, add the antioxidant and anti-sulfurization agent to the core-shell structure conductive powder 20 and stir. The stirring speed is 30 rpm and the stirring time is 10-20 minutes.

[0169] S1.1.3 After completing step S1.1.2, cool to room temperature and store in a dry environment for later use.

[0170] In step S1.2, the segmented stirring specifically includes:

[0171] S1.2.1, First stirring stage: 10 revolutions per minute, stirring time is 3 minutes;

[0172] S1.2.2, Second mixing stage: 15 rpm, mixing time is 10 minutes;

[0173] S1.2.3, Third mixing stage: 30 rpm, mixing time is 5 minutes;

[0174] S1.2.4, Fourth mixing stage: 10 rpm, mixing time is 2 minutes;

[0175] In step S1.2, the stirring temperature is between 30 and 40 degrees Celsius. By controlling the stirring temperature in step S1.2, the material may overheat due to shearing during the preparation process, thereby preventing the failure of the effective components of the reagent.

[0176] Optionally, in step S1.3, the segmented stirring specifically includes:

[0177] S1.3.1, the fifth mixing stage, the mixing speed is 15 rpm, and the mixing time is 5 minutes;

[0178] S1.3.2, the sixth mixing stage, the mixing speed is 40 rpm, and the mixing time is 15 minutes;

[0179] S1.3.3, the seventh mixing stage, the mixing speed is 30 rpm, and the mixing time is 5 minutes;

[0180] In step S1.3, the shear temperature during stirring is less than or equal to 60 degrees Celsius. In step S1.3, a segmented stirring technique is adopted to prevent the microspheres from not being able to mix fully with the liquid silica substrate 10 due to their low density during stirring. At the same time, it is also convenient to control the internal temperature of the liquid silica substrate, ensuring the chemical stability of the microspheres in this process, especially the stability of the low-boiling-point displacement medium 32.

[0181] In the application, in step S2, the liquid electromagnetic wave shielding element is processed into a preset shape by any one of the molding methods of injection molding, coating molding, compression molding, extrusion molding or dispensing molding.

[0182] In this application, in step S3, the core-shell structure conductive powder 20 is magnetized by magnetic forming or magnetic shaping. Specifically, during magnetization of the core-shell structure conductive powder 20, the magnetic flux is between 100 and 2500 Gauss, and the magnetization time is between 1 and 15 seconds.

[0183] When the core-shell structure conductive powder 20 is magnetized, the core-shell structure conductive powder 20 and the microsphere core-shell structure 30 are uniformly distributed in the liquid electromagnetic wave shielding element, and the core-shell structure conductive powder 20 is sorted in this process, so that the core-shell structure conductive powder particles are in full contact to form a conductive path in the liquid silicone substrate 10.

[0184] In this application, in step S4, the liquid electromagnetic wave shielding element is cured at high temperature. Since the displacement medium 32 inside the microsphere shell core structure 30 is made of a low boiling point material, it boils and evaporates after being heated to replace air into the cavity 33, thereby forming a sealed cavity 33 inside the microsphere shell core structure 30.

[0185] Specifically, in step S4 of this application, the high-temperature curing temperature is any value between 130 and 200 degrees Celsius, and the high-temperature curing time is between 10 and 40 minutes.

[0186] Compared with the prior art, the method for preparing the electromagnetic wave shielding element provided in this application is used to prepare the electromagnetic wave shielding element provided in any of the above-mentioned methods, and its beneficial effects are the same as those of the electromagnetic wave shielding element, which will not be elaborated here.

[0187] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An electromagnetic wave shielding element, characterized in that, include: Liquid silicone substrates can be processed into preset shapes; Core-shell structured conductive powder is mixed within the liquid silicone substrate and uniformly distributed within the liquid silicone substrate; The microsphere shell-core structure is mixed in the liquid silica substrate and uniformly distributed within the liquid silica substrate to replace a portion of the liquid silica substrate within the liquid silica substrate; The microsphere shell-core structure includes an outer shell and a displacement medium filled inside the outer shell. The displacement medium is used to form the core structure of the microsphere shell-core structure. The outer shell is made of an elastic material. The displacement medium is used to vaporize at high temperature and place air inside the outer shell to form a sealed cavity inside the outer shell. The core-shell structure conductive powder is used to shield electromagnetic waves, and the microsphere core-shell structure is used to change the impedance of the electromagnetic wave shielding element.

2. The electromagnetic wave shielding element as described in claim 1, characterized in that, The outer shell is made of polymethyl methacrylate.

3. The electromagnetic wave shielding element according to claim 2, characterized in that, The replacement medium is any one of n-hexane, ethyl acetate, chloroform, and dichloromethane.

4. The electromagnetic wave shielding element according to claim 3, characterized in that, The diameter of the cavity is less than or equal to 0.3 times the wavelength of the target electromagnetic wave.

5. The electromagnetic wave shielding element according to claim 4, characterized in that, The outer shell diameter is less than or equal to 40 micrometers.

6. The electromagnetic wave shielding element as described in claim 1 or 5, characterized in that, The preset shape is either sheet-like or strip-like.

7. The electromagnetic wave shielding element as described in claim 6, characterized in that, When the preset shape is strip-shaped, the cross-sectional shape of the preset shape can be any one of trapezoid, n-shape, D-shape or triangle.

8. The electromagnetic wave shielding element as described in claim 1, characterized in that, The density of the electromagnetic wave shielding element is between 1.3 and 1.8 g / cm³. 3 .

9. The electromagnetic wave shielding element as described in claim 1, characterized in that, The compression ratio of the electromagnetic wave shielding element is between 10% and 60%.

10. An electromagnetic wave shielding device, characterized in that, include: An electromagnetic wave shielding element, wherein the electromagnetic wave shielding element is the electromagnetic wave shielding element according to any one of claims 1-9.

11. A formulation for an electromagnetic wave shielding element, characterized in that, By composition, it includes the following components: 40-80 parts of core-shell structured conductive powder; Antioxidant 2-5 parts; Anti-sulfurization agent 1-10 parts; 15-50 parts of liquid silica gel; 1-10 parts of platinum catalyst solution; 5-20 parts of decanyltrimethoxysilane; 0.5–3 parts of the microsphere shell-core structure.

12. A method for preparing an electromagnetic wave shielding element, used to prepare the electromagnetic wave shielding element as described in claim 1 or 11, characterized in that, The following steps are included: S1, Prepare liquid electromagnetic wave shielding components; S2, the electromagnetic wave shielding element of the liquid is processed into a preset shape; S3, magnetize the core-shell structure conductive powder inside the electromagnetic wave shielding element; S4, the liquid electromagnetic wave shielding element is cured at high temperature, and the displacement medium in the microsphere shell-core structure inside the electromagnetic wave shielding element is vaporized, and the liquid electromagnetic wave shielding element is formed into an elastic and solid electromagnetic wave shielding element.

13. The method for preparing the electromagnetic wave shielding element as described in claim 12, characterized in that, Step S1 specifically includes: S1.1 After stirring and preheating the core-shell structure conductive powder, add antioxidants and anti-sulfurization agents, continue stirring, and then cool; S1.2, the platinum catalyst solution and decantrimethoxysilane are mixed into liquid silica gel, and the mixture is stirred in stages while controlling the stirring temperature; S1.3, the microsphere shell-core structure is mixed into the liquid silica substrate and stirred in stages while controlling the stirring temperature to obtain an initial mixture; S1.4, The core-shell structure conductive powder is mixed into the initial mixture and stirred, and the stirring temperature is controlled to obtain the electromagnetic wave shielding element in the state described above.

14. The method for preparing the electromagnetic wave shielding element as described in claim 13, characterized in that, Step S1.1 specifically includes: S1.1.1, the core-shell structure conductive powder is stirred and preheated, wherein the stirring speed is 15 rpm, the stirring temperature is between 50 and 80 degrees Celsius, and the stirring time is between 3 and 6 minutes; S1.1.2 After completing step S1.1.2, the antioxidant and anti-sulfurization agent are added to the core-shell structure conductive powder and stirred, wherein the rotation speed is 30 rpm and the stirring time is 10-20 minutes; S1.1.3 After completing step S1.1.2, cool to room temperature.

15. The method for preparing the electromagnetic wave shielding element as described in claim 14, characterized in that, In step S1.2, the segmented stirring specifically includes: S1.2.1, First stirring stage: 10 revolutions per minute, stirring time is 3 minutes; S1.2.2, Second mixing stage: 15 rpm, mixing time is 10 minutes; S1.2.3, Third mixing stage: 30 rpm, mixing time is 5 minutes; S1.2.4, Fourth mixing stage: 10 rpm, mixing time is 2 minutes; In step S1.2, the stirring temperature is between 30 and 40 degrees Celsius.

16. The method for preparing the electromagnetic wave shielding element as described in claim 15, characterized in that, In step S1.3, the segmented stirring specifically includes: S1.3.1, Fifth stirring stage, stirring speed is 15 rpm, stirring time is 5 minutes; S1.3.2, the sixth mixing stage, the mixing speed is 40 rpm, and the mixing time is 15 minutes; S1.3.3, the seventh mixing stage, the mixing speed is 30 rpm, and the mixing time is 5 minutes; In step S1.3, the shear temperature during stirring is less than or equal to 60 degrees Celsius.

17. The method for preparing the electromagnetic wave shielding element as described in claim 12, characterized in that, In step S2: The liquid electromagnetic wave shielding element is processed into the preset shape using any one of the following molding methods: injection molding, coating molding, compression molding, extrusion molding, or dispensing molding.

18. The method for preparing the electromagnetic wave shielding element as described in claim 12, characterized in that, In step S3: The core-shell conductive powder structure is magnetized by magnetic forming or magnetic shaping. Specifically, when magnetizing the core-shell structure conductive powder, the magnetic flux is 100–2500 Gauss and the magnetization time is 1–15 seconds.

19. The method for preparing the electromagnetic wave shielding element as described in claim 12, characterized in that, In step S4: The high-temperature curing temperature is 130–200 degrees Celsius; The high-temperature curing time is 10 to 40 minutes.

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