Electromagnetic wave shielding element, formula, preparation method and electromagnetic wave shielding equipment

Abstract

The invention provides an electromagnetic wave shielding element, a formula, a preparation method and electromagnetic wave shielding equipment, the electromagnetic wave shielding element comprises a liquid silica gel substrate, and the liquid silica gel substrate can be processed into a preset shape according to needs; shell-core structure conductive powder and a microsphere shell-core structure are mixed in the liquid silica gel substrate, an outer shell of the microsphere shell-core structure is made of an elastic material, the microsphere shell-core structure is filled with a replacement medium, and the replacement medium forms a closed cavity in the microsphere shell-core structure after being heated. The microsphere shell-core structure replaces a part of the liquid silica gel substrate in the liquid silica gel substrate to reduce the weight of the electromagnetic wave shielding element, the shell-core structure conductive powder is used for shielding electromagnetic waves, and the microsphere shell-core 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 the electromagnetic wave shielding effect is improved. And electromagnetic waves can be absorbed.

Description

Technical Field

[0001] The present application belongs to the field of electromagnetic shielding and sealing technology, and more specifically, relates to an electromagnetic wave shielding element, a formulation, a preparation method and an electromagnetic wave shielding device. Background Art

[0002] With the rapid development of modern science and technology, the demand for electromagnetic shielding technology in the fields of intelligent driving cars, national defense and military industry, high-speed communication base stations, data centers, etc. is increasing. In these applications, electromagnetic interference (EMI) has become one of the key factors restricting the stability and performance of equipment. 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 technical research and engineering applications.

[0003] In electronic devices, PCBA circuit boards are the most basic unit for electromagnetic interference protection. Electromagnetic shielding at the PCBA board level is not only related to the stability of individual components, but also determines the electromagnetic compatibility (EMC) of the entire device.

[0004] Traditional electromagnetic shielding technology usually relies on the use of conductive materials, such as conductive metal shielding covers, conductive coatings, and shielding strips. Although these materials can effectively isolate electromagnetic waves, they are solid structures and often have high density, weight, and high cost. They are also difficult to meet the performance requirements in extreme environments such as high and low temperatures, and their elastic properties need to be improved. In addition, Figure 1 As shown, the traditional shielding material is only filled with core-shell structure conductive powder, so the shielding material only has electromagnetic shielding function, lacks wave absorbing ability, and cannot effectively reduce electromagnetic wave reflection, resulting in unsatisfactory shielding effect. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide an electromagnetic wave shielding element, a formulation, 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, the first aspect of the present application is to provide an electromagnetic wave shielding element, comprising:

[0007] Liquid silicone base, which can be processed into preset shapes;

[0008] Core-shell structure conductive powder is mixed in the liquid silicone base and evenly distributed in the liquid silicone base 10;

[0009] A microsphere shell-core structure is mixed in the liquid silicone base and evenly distributed in the liquid silicone base to replace a portion of the liquid silicone base in the liquid silicone base;

[0010] The microsphere core-shell structure comprises an outer shell and a displacement medium filled in the outer shell, the displacement medium is used to form the inner core structure of the microsphere core-shell structure, the outer shell is made of elastic material, and the displacement medium is used to vaporize at high temperature and place air in the outer shell to form a closed cavity in the outer shell;

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

[0012] Optionally,

[0013] The outer shell is made of polymethacrylic acid.

[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 outer shell has a diameter less than or equal to 40 microns.

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

[0018] Optionally, when the preset shape is a strip, the cross-section of the preset shape is 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 / cm 3 .

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

[0022] Compared with the prior art, the electromagnetic wave shielding element provided by the present application is filled with a microsphere shell-core structure in the liquid silicone base to replace part of the liquid silicone base in the liquid silicone base, and the outer shell of the microsphere shell-core structure is made of an elastic material, and a closed cavity is formed inside it after heating. The beneficial effects of the electromagnetic wave shielding element provided by the present application are:

[0023] 1. After the microsphere shell-core structure is filled into the liquid silicone substrate, a closed cavity is formed inside it after heating, which reduces the density of the electromagnetic wave shielding element. Compared with the prior art, the density of the electromagnetic wave shielding element is 1.3-1.8 g / cm 3, thereby reducing the mass of the electromagnetic wave shielding element, so as to facilitate lightweighting of electronic products using the electromagnetic wave shielding element;

[0024] 2. After the microsphere shell-core structure is filled into the liquid silicone base, it does not affect the mutual distribution between the particles of the conductive powder structure. Since the outer shell of the microsphere shell-core structure is made of elastic material and a closed cavity is formed inside it after heating, the electromagnetic wave shielding element is easier to be compressed. After compression, it is easier to form conductive contact between the conductive powders of the shell-core structure, thereby improving the conductivity of the electromagnetic wave shielding element, thereby reducing the resistance of the electromagnetic wave shielding element, so as to improve the shielding performance of electromagnetic waves. At the same time, after the electromagnetic wave shielding element is compressed, the internal compression stress is lower than that of the electromagnetic wave shielding element in the prior art, so that the electromagnetic wave shielding element is suitable for the use environment requiring low compression stress in automotive electronic components;

[0025] 3. Since the liquid silicone substrate and the outer shell of the microsphere core-shell structure are both elastic after curing, after the liquid silicone substrate is cured and formed, due to its low density and small 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, so that the electromagnetic wave shielding element is not easy to produce permanent deformation, resulting in the electromagnetic wave shielding element not easy to crack and short-circuit;

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

[0027] 5. Since a closed cavity is formed inside the microsphere shell-core structure after heating, after the microsphere shell-core structure is filled into the liquid silicone substrate, the impedance of the electromagnetic wave shielding element is changed, so that the electromagnetic wave shielding element also has the function of absorbing electromagnetic waves;

[0028] 6. Since a closed cavity is formed inside the microsphere shell-core structure after heating, liquid and gas will not penetrate the electromagnetic wave shielding element compared to the existing open-pore foam structure, making the electromagnetic wave shielding element more widely applicable. The closed cavity formed inside the microsphere shell-core structure has a certain volume, and the microsphere shell-core structure is made of elastic material, and the diameter of the microsphere shell-core structure can be adjusted by heating. Since there is gas in the cavity, after the microsphere shell-core structure is compressed, the shape of the microsphere shell-core structure recovers well, so that the appearance of the electromagnetic wave shielding element will not be significantly deformed.

[0029] In a second aspect, the present application provides an electromagnetic wave shielding device, comprising:

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

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

[0032] In a third aspect, the present application provides a formula for an electromagnetic wave shielding element, which comprises the following components:

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

[0034] 2-5 parts of antioxidant;

[0035] 1 to 10 parts of anti-sulfurization agent;

[0036] 15-50 parts of liquid silicone;

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

[0038] 5-20 parts of deoxytrimethoxysilane;

[0039] Microsphere core-shell structure 0.5 to 3 parts.

[0040] Compared with the prior art, the formula of the electromagnetic wave shielding element provided in the present application is used to produce the electromagnetic wave shielding element provided by any of the above items, and its beneficial effects are the same as the beneficial effects of the above electromagnetic wave shielding elements, which will not be repeated here.

[0041] In a fourth aspect, the present application provides a method for preparing an electromagnetic wave shielding element, which is used to prepare the electromagnetic wave shielding element provided by any one of the above items, comprising the following steps:

[0042] S1, preparing a liquid electromagnetic wave shielding element;

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

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

[0045] S4, curing the liquid electromagnetic wave shielding element at high temperature, vaporizing the replacement medium in the microsphere shell core structure in the electromagnetic wave shielding element, and forming the liquid electromagnetic wave shielding element into an elastic and solid electromagnetic wave shielding element.

[0046] Optionally, in step S1, it specifically includes:

[0047] S1.1, stirring and preheating the core-shell structure conductive powder, adding an antioxidant and an anti-sulfurizing agent, continuing to stir, and cooling;

[0048] S1.2, mixing the platinum catalyst solution and trimethoxysilane into the liquid silica gel, stirring in stages and controlling the stirring temperature;

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

[0050] S1.4, mixing the core-shell structured conductive powder into the initial mixture and stirring, and controlling the stirring temperature to obtain the electromagnetic wave shielding element in the state.

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

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

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

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

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

[0056] S1.2.1, first stirring stage: 10 rpm, stirring time is 3 minutes;

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

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

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

[0060] Wherein, 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, fifth stirring stage, stirring speed is 15 rpm, stirring time is 5 min;

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

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

[0065] Wherein, 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 by any one of injection molding, coating molding, compression molding, extrusion molding or dispensing molding.

[0068] Optionally, in step S3:

[0069] Magnetizing the core-shell structure conductive powder structure by magnetic forming or magnetic shaping;

[0070] Wherein, when the core-shell structure conductive powder is magnetized, 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 temperature of high temperature curing is 130-200 degrees Celsius;

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

[0074] Compared with the prior art, the preparation method of the electromagnetic wave shielding element provided in the present application is used to prepare the electromagnetic wave shielding element provided by any of the above items, and its beneficial effects are the same as the beneficial effects of the above electromagnetic wave shielding elements, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

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

[0077] Figure 2A schematic diagram of the internal structure of an electromagnetic wave shielding element provided in an embodiment of the present application;

[0078] Figure 3 A schematic diagram of the internal structure of the electromagnetic wave shielding element after being magnetized provided in an embodiment of the present application;

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

[0080] Figure 5 A schematic diagram of the structure of the cavity in the microsphere core-shell structure provided in an embodiment of the present application;

[0081] Figure 6 A cross-sectional view of an electromagnetic wave shielding element provided in one embodiment of the present application;

[0082] Figure 7 A cross-sectional view of an electromagnetic wave shielding element provided in another embodiment of the present application;

[0083] Figure 8 A cross-sectional view of an electromagnetic wave shielding element provided in another embodiment of the present application;

[0084] Fig. 9 is a curve diagram showing the relationship between the diameter of the microsphere core-shell structure and the temperature in the present application;

[0085] Fig.10 This is a curve diagram showing the relationship between the compression rate and the electromagnetic wave shielding rate of the electromagnetic wave shielding element in this application.

[0086] Among them, the reference numerals in the figure are:

[0087] 10. Liquid silicone substrate; 20. Core-shell structure conductive powder; 30. Microsphere core-shell structure; 31. Outer shell; 32. Replacement medium; 33. Cavity. DETAILED DESCRIPTION

[0088] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

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

[0090] Please also read Figures 1 to 10, an electromagnetic wave shielding element, formulation, preparation method and electromagnetic wave shielding equipment provided in the embodiments of the present application are now described.

[0091] To achieve the above objectives, a first aspect of the present application is to provide an electromagnetic wave shielding element, comprising a liquid silicone substrate 10 , a core-shell structured 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 one of injection molding, coating molding, compression molding, extrusion molding or dispensing molding. After being processed into a preset shape, the liquid silicone substrate 10 is set at a preset position, such as at a gap in the electromagnetic shielding device, or at a position between an opening of a shielding box and a cover plate in the electromagnetic device.

[0093] See also Figure 2 and Figure 3 The core-shell structured conductive powder 20 is mixed in the silica gel base and evenly distributed in the silica gel base, and the core-shell structured conductive powder 20 is a particle with conductivity and ferromagnetism.

[0094] When the core-shell structure conductive powder 20 is formed or shaped by magnetic force, when a magnetic field is applied to the liquid silicone base 10 material, since the core-shell structure conductive powder 20 has ferromagnetism, under the influence of the magnetic field, the core-shell structure conductive powder 20 is oriented in the same direction as the magnetic field, such as the core-shell structure conductive powder 20 is arranged along the direction of the magnetic field, and after the liquid silicone base 10 is processed into a preset shape, the core-shell structure conductive powder 20 contacts each other to conduct electricity, thereby electromagnetically shielding electromagnetic waves.

[0095] At the same time, since the core-shell structured conductive powder 20 is ferromagnetic and can be affected by the magnetic field, the strength and action time of the magnetic field can be adjusted as needed to orient the core-shell structured conductive powder 20 in the liquid silicone substrate 10 and adapt to preset shapes of different shapes.

[0096] When the liquid electromagnetic wave shielding element is processed into a preset shape as required, the liquid silicone substrate 10 can be cured by heating to keep the electromagnetic wave shielding element in the preset shape.

[0097] The microsphere core-shell structure 30 is mixed in the liquid silicone base 10 and evenly distributed in the liquid silicone base 10 to replace a portion of the liquid silicone base 10 in the liquid silicone base 10 .

[0098] The microsphere core-shell structure 30 includes an outer shell 31 and a replacement medium 32 filled inside the outer shell 31. The replacement medium 32 is used to form the core structure of the microsphere core-shell structure 30. The outer shell 31 is made of elastic material. The replacement medium 32 is used to vaporize at high temperature and place air into the outer shell 31 to form a closed cavity 33 in 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 cured into a preset shape by heating, the displacement medium 32 vaporizes at high temperature and displaces the air into the outer shell 31 to form a closed cavity in the outer shell 31.

[0100] See also Figure 4 , Figure 5 and Fig. 9 , when initially set, the diameter of the outer shell 31 is D1, and the diameter of the inner core structure formed by the displacement medium 32 is D2. When the liquid silicone substrate 10 is cured into a preset shape by heating, the displacement medium 32 is vaporized by heat and displaces air into the outer shell 31 to form a cavity 33 with a diameter of D2', and D2' is greater than D2. Since the outer shell 31 is made of elastic material, at this time, 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 shell core structure 30 and the diameter of the internal cavity 33 thereof can be adjusted by adjusting the temperature.

[0101] Among them, Fig. 9 In the figure, the bottom curve is the curve of the diameter change at different temperatures when the initial diameter of the microsphere shell core structure 30 is 5 microns; the middle curve is the curve of the diameter change at different temperatures when the initial diameter of the microsphere shell core structure 30 is 15 microns; the top curve is the curve of the diameter change at different temperatures when the initial diameter of the microsphere shell core structure 30 is 20 microns.

[0102] Depend on Fig. 9 It can be seen that as the temperature increases, the diameter of the microsphere core-shell structure 30 gradually increases, and the increase in the diameter of the microsphere core-shell structure 30 gradually slows down. Therefore, the diameter of the microsphere core-shell structure 30 and the diameter of its internal cavity 33 can be adjusted by adjusting the temperature.

[0103] When an electromagnetic wave passes through a microsphere core-shell structure 30 having a cavity 33, the electromagnetic wave is reflected on the surface of the microsphere core-shell structure 30. The electromagnetic wave is reflected on the surface of the microsphere core-shell structure 30 and returns, resulting in an increase in the energy loss of the electromagnetic wave. In addition, the propagation path of the electromagnetic wave inside the cavity 33 is deflected, resulting in part of the electromagnetic energy being reflected from the original direction, while the other part is scattered in other directions by the inner wall of the cavity 33. This scattering will reduce the energy of the electromagnetic wave, thereby changing the impedance of the electromagnetic wave when it passes through the microsphere core-shell structure 30, and further changing the impedance of the electromagnetic wave when it passes through the electromagnetic wave shielding element, thereby absorbing the electromagnetic wave.

[0104] In the present application, the core-shell structure conductive powder 20 is at least one of a nickel-carbon structure with carbon inside and nickel wrapped in an outer layer, a silver-carbon structure with carbon inside and silver wrapped in an outer layer, a silver-glass structure with glass inside and silver wrapped in an outer layer, and a silver-aluminum structure with aluminum inside and silver wrapped in an outer layer.

[0105] Specifically, in the present application, the outer shell 31 is made of polymethacrylic acid. 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 replacement medium 32 is heated and vaporized under the action of high temperature, and replaces the air into the cavity 33 .

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

[0108] When the diameter of the closed 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 in the cavity 33, resulting in its inability to penetrate. 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 79 GHZ electromagnetic waves as an example, its wavelength is 3.8 mm. When the diameter of the cavity 33 is smaller than the target 0.3*3.8=0.114 mm, the 79 GHZ electromagnetic waves cannot penetrate the closed cavity 33 with a diameter less than or equal to 0.114 mm, so that the electromagnetic wave shielding element has an absorbing function for electromagnetic waves.

[0110] When the electromagnetic wave shielding element is set at a preset position, it will be compressed by the components located on both sides thereof, and 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 becomes smaller than 0.3 times the wavelength of the target electromagnetic wave, further preventing the electromagnetic wave from penetrating the cavity 33.

[0111] In one embodiment of the present application, the diameter of the outer shell 31 is less than or equal to 40 microns.

[0112] Since the cavity 33 is arranged in the outer shell 31 and its diameter is smaller than the diameter of the outer shell 31, when the diameter of the outer shell 31 is less than or equal to 40 microns, the diameter of the cavity 33 inside it is much smaller than 40 microns. Electromagnetic waves of various wavelengths can be diffracted in the cavity 33 when passing through the micropores, making them unable to penetrate, thereby enabling the electromagnetic wave shielding element to achieve the wave absorbing function for electromagnetic waves of various wavelengths.

[0113] In the present application, since the silicone base is in liquid form, the liquid silicone base 10 can be made into a sheet or strip shape by any one of 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 a desired shape, such as a triangle, a rectangle or a circle. When the liquid silicone substrate 10 is made into a strip structure, its shape can be a long strip structure, or a ring structure, and can be made into a shape suitable for the place of use as needed.

[0115] In this application, please refer to Figures 6 to 8 When the preset shape is a strip, the cross-section of the preset shape is any one of a trapezoid, an N-shape, a D-shape or a triangle, or can be processed into a shape adapted to the place of use as needed.

[0116] In the present application, since the microsphere shell core structure 30 having 33 is filled in the liquid silicone substrate 10, the density of the electromagnetic wave shielding element can be set at 1.3-1.8 g / cm by adjusting the proportion of the microsphere shell core structure 30 in the liquid silicone substrate 10. For example, when the microsphere shell core structure 30 is filled in the liquid silicone substrate 10 with the largest proportion, since part of the silicone substrate in the liquid silicone substrate 10 is replaced by more cavities 33, the density of the electromagnetic wave shielding element is 1.4 g / cm. When the microsphere shell core structure 30 is filled in the liquid silicone substrate 10 with the smallest proportion, the density of the electromagnetic wave shielding element is 1.75 g / cm.

[0117] Compared with the electromagnetic wave shielding element in the prior art which is not filled with the microsphere core-shell structure 30, the electromagnetic wave shielding element provided in the present application which is filled with the microsphere core-shell structure 30 has a lower mass, so that the electronic products using the electromagnetic wave shielding element can be lightweight.

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

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

[0120] For example, when the volume of the electromagnetic wave shielding element is compressed, the shell-core structure conductive powder 20 inside it is easier to form conductive contact, thereby improving the electromagnetic wave shielding element. At the same time, the diameter of the microsphere shell-core structure 30 and the volume of the cavity 33 inside it are also compressed. When the volume of the electromagnetic wave shielding element is compressed by 10%, the diameter of the microsphere shell-core structure 30 and the volume of the cavity 33 inside it are also compressed by 10%. At this time, the diameter of the microsphere shell-core structure 30 is 40*(1-10%)=36 microns. At this time, the diameter of the cavity 33 inside the microsphere shell-core structure 30 is further compressed, further improving the electromagnetic wave shielding element to achieve the wave absorption function of electromagnetic waves of multiple wavelengths.

[0121] Table 1: When the core-shell structure conductive powder 20 is a nickel-carbon structure, the internal compressive stress of electromagnetic wave shielding components of different sizes at different compression processes in the present application;

[0122]

[0123] Table 2: Compressive stress inside electromagnetic wave shielding components 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] It can be seen from Table 1 and Table 2 that, compared with the technical solution in the prior art in which the silicone base is only filled with a core-shell structured conductive powder 20, the electromagnetic wave shielding elements provided by the present application have electromagnetic wave shielding elements of different sizes and at different compression processes, and their internal compressive stress is smaller than the internal compressive stress of the electromagnetic wave shielding elements of the same size and the same compression degree in the prior art. Since the smaller the internal compressive stress at different compression degrees, it represents that the electromagnetic wave shielding element has a stronger deformation ability, higher plasticity, and better toughness and ductility. Therefore, compared with the prior art, the electromagnetic wave shielding element provided by the present application has better deformation ability, plasticity, toughness and ductility than the electromagnetic wave shielding elements in the prior art. Therefore, the electromagnetic wave shielding element provided by the present application can adapt to greater stress and is not prone to rupture.

[0126] Table 3: In the present application, when the core-shell structure conductive powder 20 is a nickel-carbon structure, the internal resistance of electromagnetic wave shielding components of different sizes at different compression ranges;

[0127]

[0128] It can be seen from Table 3 that the electromagnetic wave shielding element proposed in the present application, under the same size, with the increase of compression rate, the resistance value component of the electromagnetic wave shielding element decreases, and after the electromagnetic wave shielding element is compressed, it is easier to form conductive contact between the shell-core structure conductive powder 20, thereby improving the conductivity of the electromagnetic wave shielding element, so as to improve the shielding performance of electromagnetic waves.

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

[0130] See also Fig.10 , Fig.10 In the example, the core-shell structure conductive powder 20 is a nickel-carbon structure, H: 1.6 mm, the vertical axis is SE (Shielding Effectiveness, electromagnetic shielding rate), and the horizontal axis is the compression rate of the electromagnetic wave shielding element. Fig.10 It can be seen that, under the same size, as the compression rate of the electromagnetic wave shielding element increases, the electromagnetic shielding rate of the electromagnetic wave shielding element against electromagnetic waves gradually increases.

[0131] Compared with the prior art, the electromagnetic wave shielding element provided by the present application is filled with a microsphere shell-core structure 30 in the liquid silicone substrate 10, and the liquid silicone substrate 10 replaces part of the liquid silicone substrate 10, and the outer shell 31 of the microsphere shell-core structure 30 is made of elastic material, and a closed cavity 33 is formed inside after heating. The electromagnetic wave shielding element provided by the present application has the following beneficial effects:

[0132] 1. After the microsphere core-shell structure 30 is filled into the liquid silicone substrate 10, a closed cavity 33 is formed inside the microsphere core-shell structure 30 after heating, thereby reducing the density of the electromagnetic wave shielding element. Compared with the prior art, the density of the electromagnetic wave shielding element is 1.3-1.8 g / cm, thereby reducing the mass of the electromagnetic wave shielding element, so that the electronic product using the electromagnetic wave shielding element can be lightweight;

[0133] 2. After the microsphere core-shell structure 30 is filled into the liquid silicone substrate 10, the mutual distribution between the particles of the conductive powder 20 of the core-shell structure is not affected. Moreover, since the outer shell 31 of the microsphere core-shell structure 30 is made of elastic material and a closed cavity 33 is formed inside it after heating, the electromagnetic wave shielding element is more easily compressed, and after compression, it is easier to form conductive contact between the core-shell structure conductive powder 20, thereby improving the conductivity of the electromagnetic wave shielding element, thereby reducing the resistance of the electromagnetic wave shielding element, so as to improve the shielding performance of electromagnetic waves. At the same time, after the electromagnetic wave shielding element is compressed, the internal compression stress is lower than that of the electromagnetic wave shielding element in the prior art, so that the electromagnetic wave shielding element is suitable for the use environment requiring low compression stress in automotive electronic components;

[0134] 3. Since the liquid silicone substrate 10 is elastic after solidification and the outer shell 31 of the microsphere core-shell structure 30 is elastic, after the liquid silicone substrate 10 is solidified and formed, due to its low density and small 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, so that the electromagnetic wave shielding element is not easy to produce permanent deformation, resulting in the electromagnetic wave shielding element not easy to crack and short-circuit;

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

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

[0137] 6. After the microsphere shell-core structure 30 is heated, a closed cavity 33 is formed inside it. Compared with the existing open-pore foam structure, liquid and gas will not penetrate the electromagnetic wave shielding element, making the electromagnetic wave shielding element more widely applicable. The closed cavity 33 formed 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, and the diameter of the microsphere shell-core structure 30 can be adjusted by heating. Since there is gas in the cavity 33, after the microsphere shell-core structure 30 is compressed, the shape of the microsphere shell-core structure 30 is well restored, so that the appearance of the electromagnetic wave shielding element will not be significantly deformed.

[0138] In a second aspect, the present application provides an electromagnetic wave shielding device, comprising an electromagnetic wave shielding element, where the electromagnetic wave shielding element is the electromagnetic wave shielding element provided by any one of the above embodiments.

[0139] The electromagnetic wave shielding element is arranged at the gap of the electromagnetic wave shielding device to electromagnetically shield and absorb electromagnetic waves at the gap of the electromagnetic wave shielding device, thereby improving the shielding effect of the electromagnetic wave shielding device on electromagnetic waves.

[0140] It should be noted that the electromagnetic wave shielding device can be used to shield electromagnetic waves from various communication base stations, mobile phones or controllers in smart car driving control.

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

[0142] In a third aspect, the present application provides a formula for an electromagnetic wave shielding element, which comprises the following components:

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

[0144] 2-5 parts of antioxidant;

[0145] 1 to 10 parts of anti-sulfurization agent;

[0146] 15-50 parts of liquid silicone;

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

[0148] 5-20 parts of deoxytrimethoxysilane;

[0149] Microsphere core-shell structure 0.5 to 3 parts.

[0150] Compared with the prior art, the formula of the electromagnetic wave shielding element provided in the present application is used to produce the electromagnetic wave shielding element provided by any of the above items, and its beneficial effects are the same as the beneficial effects of the above electromagnetic wave shielding elements, which will not be repeated here.

[0151] In the present application, antioxidants and anti-sulfurizing agents are added to the core-shell structure conductive powder 20, and heated and stirred to mix evenly, and then cooled to room temperature for use. Platinum catalyst solution and deoxytrimethoxysilane are mixed into liquid silica gel and stirred to mix evenly, and then added into the microsphere core-shell structure 30 structure and stirred to mix to obtain an initial mixture, and then the core-shell structure conductive powder 20 mixed with antioxidants and anti-sulfurizing 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 one of 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 plasticity, and the core-shell structure conductive powder 20 is contacted with each other to form a conductive structure to electromagnetically shield the electromagnetic waves, and then the liquid electromagnetic wave shielding element is cured and shaped by high temperature to keep the electromagnetic wave shielding element in the preset shape.

[0153] In one embodiment of the present application, the formula of the electromagnetic wave shielding element includes, by components: 40 parts of core-shell structure conductive powder, 2 parts of antioxidant, 1 part of anti-sulfurization agent, 15 parts of liquid silicone, 1 part of platinum catalyst solution, 5 parts of deoxytrimethoxysilane, and 0.5 parts of microsphere core-shell structure.

[0154] In another embodiment of the present application, the formula of the electromagnetic wave shielding element includes, by components: 80 parts of core-shell structure conductive powder, 5 parts of antioxidant, 10 parts of anti-sulfurization agent, 50 parts of liquid silicone, 10 parts of platinum catalyst solution, 20 parts of deoxytrimethoxysilane, and 3 parts of microsphere core-shell structure.

[0155] In a fourth aspect, the present application provides a method for preparing an electromagnetic wave shielding element, which is used to prepare the electromagnetic wave shielding element provided by any one of the above embodiments, and comprises the following steps:

[0156] S1, preparing a liquid electromagnetic wave shielding element;

[0157] S2, processing the liquid electromagnetic wave shielding element into a preset shape;

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

[0159] S4, curing the liquid electromagnetic wave shielding element at high temperature, vaporizing the replacement medium 32 in the microsphere shell core structure 30 in the electromagnetic wave shielding element, and forming the liquid electromagnetic wave shielding element into an elastic and solid electromagnetic wave shielding element.

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

[0161] S1.1, stirring and preheating the core-shell structure conductive powder 20, adding an antioxidant and an anti-sulfurizing agent, and continuing to stir, cooling to room temperature, and storing in a dry environment for later use;

[0162] S1.2, mixing the platinum catalyst solution and trimethoxysilane into the liquid silica gel, stirring in stages and controlling the stirring temperature;

[0163] S1.3, mixing the microsphere core-shell structure 30 into the liquid silicone substrate 10, stirring in sections and controlling the stirring temperature to obtain an initial mixture;

[0164] S1.4, mixing the core-shell structure conductive powder 20 into the initial mixture and stirring, and controlling the stirring temperature to obtain an electromagnetic wave shielding element in a solid state.

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

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

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

[0168] S1.1.2, after completing step S1.1.2, adding an antioxidant and an anti-sulfurizing agent to the core-shell structure conductive powder 20 and stirring, wherein the rotation speed is 30 rpm and the stirring time is 10 to 20 minutes;

[0169] S1.1.3, after completing step S1.1.2, cool to room temperature, and after cooling to room temperature, 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 rpm, stirring time is 3 minutes;

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

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

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

[0175] Wherein, in step S1.2, the stirring temperature is between 30 and 40 degrees Celsius. In step S1.2, the stirring temperature is controlled to prevent the material from being overheated due to shearing during the preparation process, thereby preventing the effective ingredients of the reagent from becoming ineffective.

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

[0177] S1.3.1, fifth stirring stage, stirring speed is 15 rpm, stirring time is 5 min;

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

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

[0180] Among them, 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 technical solution is adopted to prevent the microspheres from being unable to fully mix with the liquid silicone substrate 10 due to their low density during the stirring process. At the same time, it is also convenient to control the temperature inside the liquid silicone substrate to ensure the chemical stability of the microspheres in this process, especially the stability of the low-boiling point replacement 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 injection molding, coating molding, compression molding, extrusion molding or dispensing molding.

[0182] In the present application, in step S3, the core-shell structure conductive powder 20 is magnetized by magnetic forming or magnetic shaping. When the core-shell structure conductive powder 20 is magnetized, the magnetic flux is 100 to 2500 Gauss, and the magnetization time is 1 to 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 evenly 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 fully in contact with each other to form a conductive path in the liquid silicone substrate 10.

[0184] In the present application, in step S4, the liquid electromagnetic wave shielding element is cured at high temperature. Since the replacement 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 the air into the cavity 33, thereby forming a closed cavity 33 in the microsphere shell core structure 30.

[0185] Specifically, in step S4 of the present application, the temperature of high temperature curing is any temperature 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 preparation method of the electromagnetic wave shielding element provided in the present application is used to prepare the electromagnetic wave shielding element provided by any of the above items, and its beneficial effects are the same as the beneficial effects of the above electromagnetic wave shielding elements, which will not be repeated here.

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

Claims

1. An electromagnetic wave shielding element, characterized in that: include: Liquid silicone base, which can be processed into preset shapes; Core-shell structure conductive powder is mixed in the liquid silicone base and evenly distributed in the liquid silicone base; A microsphere shell-core structure is mixed in the liquid silicone base and evenly distributed in the liquid silicone base to replace a portion of the liquid silicone base in the liquid silicone base; The microsphere core-shell structure comprises an outer shell and a displacement medium filled in the outer shell, the displacement medium is used to form the inner core structure of the microsphere core-shell structure, the outer shell is made of elastic material, and the displacement medium is used to vaporize at high temperature and place air in the outer shell to form a closed cavity in the outer shell; The core-shell structure conductive powder is used for shielding electromagnetic waves, and the core-shell structure of the microsphere is used for changing the impedance of the electromagnetic wave shielding element.

2. The electromagnetic wave shielding element according to claim 1, characterized in that The outer shell is made of polymethacrylic acid.

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 has a diameter less than or equal to 40 microns.

6. The electromagnetic wave shielding element according to claim 1 or 5, characterized in that: The preset shape is a sheet or a strip.

7. The electromagnetic wave shielding element according to claim 6, characterized in that When the preset shape is a strip, the cross-section of the preset shape is any one of a trapezoid, an n-shape, a D-shape or a triangle.

8. The electromagnetic wave shielding element according to claim 1, wherein The density of the electromagnetic wave shielding element is between 1.3 and 1.8 g / cm 3 .

9. The electromagnetic wave shielding element according to claim 1, wherein: The compression rate 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 to 9.

11. A formula for an electromagnetic wave shielding element, characterized in that: In terms of components, it includes the following components: 40-80 parts of core-shell structure conductive powder; 2-5 parts of antioxidant; 1 to 10 parts of anti-sulfurization agent; 15-50 parts of liquid silicone; 1 to 10 parts of platinum catalyst solution; 5-20 parts of deoxytrimethoxysilane; Microsphere core-shell structure 0.5 to 3 parts.

12. A method for preparing an electromagnetic wave shielding element, used for preparing the electromagnetic wave shielding element as claimed in claim 1 or 11, characterized in that: The steps include: S1, preparing a liquid electromagnetic wave shielding element; S2, processing the electromagnetic wave shielding element of the liquid into a preset shape; S3, magnetizing the core-shell structure conductive powder in the electromagnetic wave shielding element; S4, curing the liquid electromagnetic wave shielding element at high temperature, vaporizing the replacement medium in the microsphere shell core structure in the electromagnetic wave shielding element, and forming the liquid electromagnetic wave shielding element into an elastic and solid electromagnetic wave shielding element.

13. The method for preparing an electromagnetic wave shielding element according to claim 12, characterized in that: In step S1, it specifically includes: S1.1, stirring and preheating the core-shell structure conductive powder, adding an antioxidant and an anti-sulfurizing agent, continuing to stir, and cooling; S1.2, mixing the platinum catalyst solution and trimethoxysilane into the liquid silica gel, stirring in stages and controlling the stirring temperature; S1.3, mixing the microsphere core-shell structure into the liquid silica gel substrate, stirring in stages and controlling the stirring temperature to obtain an initial mixture; S1.4, mixing the core-shell structured conductive powder into the initial mixture and stirring, and controlling the stirring temperature to obtain the electromagnetic wave shielding element in the state.

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

2.

15. The method for preparing an electromagnetic wave shielding element according to claim 14, characterized in that: In step S1.2, the segmented stirring specifically includes: S1.2.1, first stirring stage: 10 rpm, stirring time is 3 minutes; S1.2.2, second stirring stage: 15 rpm, stirring time is 10 minutes; S1.2.3, third stirring stage: 30 rpm, stirring time is 5 minutes; S1.2.4, fourth stirring stage: 10 rpm, stirring time is 2 minutes; Wherein, in step S1.2, the stirring temperature is between 30 and 40 degrees Celsius.

16. The method for preparing an electromagnetic wave shielding element according to 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 min; S1.3.2, sixth stirring stage, stirring speed is 40 rpm, stirring time is 15 minutes; S1.3.3, seventh stirring stage, stirring speed is 30 rpm, stirring time is 5 minutes; Wherein, in step S1.3, the shear temperature during stirring is less than or equal to 60 degrees Celsius.

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

18. The method for preparing an electromagnetic wave shielding element according to claim 12, wherein: In step S3: Magnetizing the core-shell structure conductive powder structure by magnetic forming or magnetic shaping; Wherein, when the core-shell structure conductive powder is magnetized, the magnetic flux is 100 to 2500 Gauss and the magnetization time is 1 to 15 seconds.

19. The method for preparing an electromagnetic wave shielding element according to claim 12, wherein: In step S4: The temperature of high temperature curing is 130-200 degrees Celsius; The high temperature curing time is 10 to 40 minutes.

Images