Variable-frequency phase-change wave-absorbing gasket and preparation method thereof

Abstract

The invention provides a variable-frequency phase-change wave-absorbing gasket and a preparation method thereof. The phase-change wave-absorbing gasket comprises a solid wave-absorbing shell and a phase-change wave-absorbing material filled in the solid wave-absorbing shell; the phase-change wave-absorbing material comprises the following raw materials in parts by mass: 30-60 parts of a wave-absorbing agent, 40-70 parts of heat-conducting powder and 5-15 parts of a composite phase-change matrix, and the composite phase change matrix has more than two phase change points. The phase-change wave-absorbing material is composed of the wave-absorbing agent, the heat-conducting powder and the composite phase-change matrix, so that the phase-change wave-absorbing material can be subjected to multi-stage phase change along with temperature change, and reflection, refraction and absorption paths of electromagnetic waves in the material are increased through particle distribution and lattice arrangement change, so that the absorption effect on the electromagnetic waves is enhanced, and the service life of the material is prolonged. The wave-absorbing frequency band of the phase change wave-absorbing gasket is widened; and meanwhile, the phase change wave-absorbing gasket has high heat absorption capacity, heat generated during operation of equipment can be fully absorbed, and the phase change wave-absorbing gasket adapts to application scenes needing efficient heat dissipation.

Description

Technical Field

[0001] This application relates to the technical field of microwave absorbing materials, in particular to a frequency-variable phase-change microwave absorbing gasket and a preparation method thereof. Background Art

[0002] With the rapid development of modern wireless communication, radar and electronic devices, the problems of electromagnetic interference (EMI) and electromagnetic compatibility (EMC) have become increasingly prominent.

[0003] To suppress unnecessary electromagnetic interference, microwave absorbing materials have received extensive attention. Microwave absorbing materials can reduce electromagnetic wave reflection and interference by absorbing electromagnetic wave energy and converting it into heat energy. Common microwave absorbing materials include ferrite microwave absorbing materials and carbon-based microwave absorbing materials. Ferrite microwave absorbing materials utilize the high magnetic permeability and loss characteristics of ferrite to absorb electromagnetic waves; carbon-based microwave absorbing materials utilize the conductive loss and dielectric loss characteristics of graphene, carbon nanotubes, etc. to absorb electromagnetic waves.

[0004] However, the microwave absorption frequency band of existing microwave absorbing materials is usually fixed and cannot dynamically adjust the microwave absorption frequency band with increasing temperature to achieve wide-band coverage; moreover, the heat absorption capacity of microwave absorbing materials is limited and cannot fully absorb the heat generated during device operation, making it unable to adapt to application scenarios that require efficient heat dissipation. Summary of the Invention

[0005] In view of the above-mentioned problems, this application is proposed to provide a frequency-variable phase-change microwave absorbing gasket and a preparation method thereof that overcome or at least partially solve the above problems, including:

[0006] A frequency-variable phase-change microwave absorbing gasket, comprising: a solid microwave absorbing housing and a phase-change microwave absorbing material filled inside the solid microwave absorbing housing; the phase-change microwave absorbing material comprises the following raw materials by mass parts: 30-60 parts of a microwave absorber, 40-70 parts of a heat-conducting powder, and 5-15 parts of a composite phase-change matrix; wherein, the composite phase-change matrix has more than two phase-change points.

[0007] Preferably, the first phase-change point of the composite phase-change matrix is 40-50 °C, and the second phase-change point is 65-75 °C.

[0008] Preferably, the composite phase-change matrix comprises at least two of paraffin wax, phase-change microcapsules, polyols, polyethylene glycol, and stearic acid.

[0009] Preferably, the solid-state wave-absorbing housing comprises the following raw materials by mass parts: 60-80 parts of wave-absorbing agent, 20-30 parts of heat-conducting powder, 3-7 parts of vinyl silicone oil, 0.5-2 parts of hydrogen-containing silicone oil, 0.1-0.5 parts of catalyst, and 0.01-0.05 parts of inhibitor.

[0010] Preferably, the wave-absorbing agent comprises at least one of carbonyl iron powder, acetylene black, ferrite, silicon carbide, expanded graphite, iron-platinum alloy, iron-nickel-cobalt-titanium alloy, and nickel-manganese-based Heusler alloy.

[0011] Preferably, the heat-conducting powder comprises at least one of alumina, zinc oxide, copper powder, silver powder, indium-bismuth alloy, and Cerrolow-136 alloy.

[0012] Preferably, the catalyst is a platinum catalyst.

[0013] Preferably, the inhibitor is an ethynylcyclohexanol inhibitor.

[0014] A preparation method of a phase-change wave-absorbing gasket as described in any one of the above, comprising:

[0015] Stir and mix the wave-absorbing agent, heat-conducting powder, vinyl silicone oil, hydrogen-containing silicone oil, inhibitor, and catalyst according to the ratio, and place them in a mold for curing treatment to obtain a wave-absorbing housing monomer; wherein, the surface of the wave-absorbing housing monomer is provided with grooves;

[0016] Stir and mix the wave-absorbing agent, heat-conducting powder, and composite phase-change matrix according to the ratio to obtain a phase-change wave-absorbing material;

[0017] Fill the phase-change wave-absorbing material into the grooves of the wave-absorbing housing monomer;

[0018] Adopt an adhesive to buckle and bond two wave-absorbing housing monomers filled with the phase-change wave-absorbing material to obtain a phase-change wave-absorbing gasket.

[0019] Preferably, the adhesive is an organosilicon adhesive.

[0020] This application has the following advantages:

[0021] In view of the problems that the wave absorption frequency band of existing wave absorption materials is fixed and the heat absorption capacity is limited, the present application provides a solution of filling a phase change wave absorption material inside a solid wave absorption housing and selecting a wave absorber, a heat conduction powder, and a composite phase change matrix to form the phase change wave absorption material to dynamically adjust the wave absorption performance and improve the heat absorption performance. Specifically: a frequency-variable phase change wave absorption gasket, comprising: a solid wave absorption housing and a phase change wave absorption material filled inside the solid wave absorption housing; the phase change wave absorption material comprises the following raw materials by mass fraction: 30-60 parts of a wave absorber, 40-70 parts of a heat conduction powder, and 5-15 parts of a composite phase change matrix; wherein, the composite phase change matrix has more than two phase change points.

[0022] By filling the phase change wave absorption material inside the solid wave absorption housing, the overall wave absorption performance can be ensured, and at the same time, it plays a role in supporting and shaping the phase change wave absorption material. By selecting a wave absorber, a heat conduction powder, and a composite phase change matrix with multiple phase change points to form the phase change wave absorption material, the phase change wave absorption material can undergo multi-stage phase changes with temperature changes. Through changes in particle distribution and lattice arrangement, the reflection, refraction, and absorption paths of electromagnetic waves inside the material are increased, thereby enhancing the absorption effect of electromagnetic waves and broadening the wave absorption frequency band of the phase change wave absorption gasket; at the same time, the phase change wave absorption gasket has a strong heat absorption capacity, can fully absorb the heat generated during equipment operation, and is suitable for application scenarios that require efficient heat dissipation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the present application, the drawings required to be used in the description of the present application will be briefly introduced below. Obviously, the drawings in the following description are only a part of the embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 is a schematic structural diagram of a phase change wave absorption gasket provided by an embodiment of the present application;

[0025] Figure 2 is a step flow chart of a preparation method of a phase change wave absorption gasket provided by an embodiment of the present application.

[0026] The reference numerals in the accompanying drawings of the specification are as follows:

[0027] 10. Solid wave absorption housing; 20. Phase change wave absorption material. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] To make the objectives, features, and advantages of this application more apparent and understandable, the following further elaborates on this application in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are part of this application, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts belong to the scope of protection of this application.

[0029] Through analysis of the prior art, the inventors found that the arrangement and loss characteristics of the internal particles of existing microwave absorbing materials (such as ferrite microwave absorbing materials and carbon-based microwave absorbing materials) are less affected by temperature, and the microwave absorption range cannot be dynamically adjusted by temperature change; moreover, existing microwave absorbing materials are mainly single-functional materials with limited heat absorption capacity, unable to fully absorb the heat generated during equipment operation, and not suitable for application scenarios that require efficient heat dissipation.

[0030] Refer to Figure 1 , in an embodiment of this application, a phase-change microwave absorbing gasket with variable frequency is provided, including: a solid microwave absorbing housing 10 and a phase-change microwave absorbing material 20 filled inside the solid microwave absorbing housing 10; the phase-change microwave absorbing material 20 includes the following raw materials by mass fraction: 30-60 parts of a microwave absorber, 40-70 parts of a thermally conductive powder, and 5-15 parts of a composite phase-change matrix; wherein, the composite phase-change matrix has more than two phase-change points.

[0031] It should be noted that the volume of the phase-change microwave absorbing material 20 accounts for more than 10% of the total volume of the phase-change microwave absorbing gasket, so as to exhibit good performance in terms of microwave absorption and thermal management;

[0032] The composite phase-change matrix includes more than two phase-change components, and each of the phase-change components undergoes a phase change at different temperatures. For example, the first phase-change component undergoes a phase change at the first phase-change point, and the second phase-change component undergoes a phase change at the second phase-change point, where the second phase-change point is higher than the first phase-change point. Thus, the composite phase-change matrix undergoes a phase change at both the first phase-change point and the second phase-change point; when the temperature is lower than the first phase-change point, the phase-change microwave absorbing gasket has a first microwave absorption bandwidth; when the temperature is higher than the first phase-change point and lower than the second phase-change point, the phase-change microwave absorbing gasket has a second microwave absorption bandwidth; wherein, the second microwave absorption bandwidth is greater than the first microwave absorption bandwidth; when the temperature is higher than the second phase-change point, the phase-change microwave absorbing gasket has a third microwave absorption bandwidth; wherein, the third microwave absorption bandwidth is greater than the second microwave absorption bandwidth.

[0033] By filling the phase change absorbing material 20 inside the solid-state absorbing shell 10, the overall absorbing performance can be ensured, and at the same time, it plays a role in supporting and shaping the phase change absorbing material 20. By selecting an absorbing agent, a heat-conducting powder, and a composite phase change matrix with multiple phase change points to form the phase change absorbing material 20, the phase change absorbing material 20 can undergo multi-stage phase changes with temperature changes. Through the changes in particle distribution and lattice arrangement, the reflection, refraction, and absorption paths of electromagnetic waves inside the material are increased, thereby enhancing the absorption effect of electromagnetic waves and broadening the absorbing frequency band of the phase change absorbing gasket; at the same time, the phase change absorbing gasket has a strong heat absorption capacity, can fully absorb the heat generated during the operation of the device, and is suitable for application scenarios that require efficient heat dissipation.

[0034] Next, the phase change absorbing gasket provided by this exemplary embodiment will be further described.

[0035] In an embodiment of the present application, the first phase change point of the composite phase change matrix is 40 - 50 °C, and the second phase change point is 65 - 75 °C. The first phase change point is in a relatively low temperature range, close to the short-term working temperature of common devices (for example, for electronic devices, communication devices, etc., the temperature usually rises rapidly above 40 °C after startup). When the temperature reaches 40 - 50 °C, the composite phase change matrix undergoes the first phase change, thereby effectively increasing the absorbing bandwidth, absorbing a large amount of heat at the same time, reducing the device temperature, and ensuring the stability of device operation. The second phase change point is in a relatively high temperature range, close to the long-term working temperature of common devices (for example, for electronic devices, communication devices, etc., the temperature may rise above 65 °C after high load or long-term operation). When the temperature reaches 65 - 75 °C, the composite phase change matrix undergoes the second phase change, thereby further increasing the absorbing bandwidth and absorbing a large amount of heat at the same time, avoiding overheating damage to the device.

[0036] In an embodiment of the present application, the composite phase change matrix includes at least two of paraffin wax, phase change microcapsules, polyols, polyethylene glycol, and stearic acid. Paraffin wax, phase change microcapsules, polyols, polyethylene glycol, and stearic acid have different phase change characteristics and can absorb and release heat in different temperature ranges. Through the synergistic effect of the above phase change components, the composite phase change matrix can achieve multi-stage phase changes with temperature changes.

[0037] In one embodiment of the present application, the solid absorbing shell 10 includes the following raw materials by mass: 60-80 parts of absorbent, 20-30 parts of thermal conductive powder, 3-7 parts of vinyl silicone oil, 0.5-2 parts of hydrogenated silicone oil, 0.1-0.5 parts of catalyst and 0.01-0.05 parts of inhibitor. Through the reasonable proportion of absorbent, thermal conductive powder, vinyl silicone oil, hydrogenated silicone oil, catalyst and inhibitor, the thermal conductivity, thermal stability, mechanical strength and processability of the solid absorbing shell 10 can be improved on the basis of ensuring excellent absorbing performance.

[0038] In one embodiment of the present application, the absorbent includes at least one of carbonyl iron powder, acetylene black, ferrite, silicon carbide, expanded graphite, iron-platinum alloy, iron-nickel-cobalt-titanium alloy and nickel-manganese-based Heusler alloy. By selecting the above absorbent, the phase change absorbing gasket can be provided with efficient electromagnetic wave absorption performance.

[0039] In one embodiment of the present application, the thermally conductive powder includes at least one of aluminum oxide, zinc oxide, copper powder, silver powder, indium bismuth alloy and Cerrolow-136 alloy. By selecting the above thermally conductive powder, the phase change absorbing pad can be provided with good thermal conductivity.

[0040] In one embodiment of the present application, the catalyst is a platinum catalyst. The platinum catalyst can efficiently promote the cross-linking reaction without destroying the stability of other components.

[0041] In one embodiment of the present application, the inhibitor is an acetylene cyclohexanol inhibitor. The acetylene cyclohexanol inhibitor can effectively control the cross-linking reaction and avoid unstable material performance due to overly fast reaction.

[0042] Reference Figure 2 In one embodiment of the present application, there is also provided a method for preparing a phase change absorbing pad as described in any of the above embodiments, comprising:

[0043] S110, mixing the wave absorbing agent, the thermal conductive powder, the vinyl silicone oil, the hydrogenated silicone oil, the inhibitor and the catalyst according to the proportion, and placing the mixture in a mold for curing to obtain a wave absorbing shell monomer; wherein the surface of the wave absorbing shell monomer is provided with a groove;

[0044] S120, mixing the absorbent, the thermal conductive powder and the composite phase change matrix according to a ratio to obtain a phase change absorbing material 20;

[0045] S130, filling the phase change absorbing material 20 into the groove of the absorbing shell monomer;

[0046] S140, using an adhesive to buckle and bond the two absorbing shell monomers filled with the phase change absorbing material 20 to obtain a phase change absorbing gasket.

[0047] Next, the preparation method of the phase change wave-absorbing gasket provided by this exemplary embodiment will be further described.

[0048] As described in step S110, the wave-absorbing agent, heat-conducting powder, vinyl silicone oil, hydrogen-containing silicone oil, inhibitor, and catalyst are stirred and mixed according to the ratio, and then placed in a mold for curing treatment to obtain a wave-absorbing housing monomer; wherein, grooves are provided on the surface of the wave-absorbing housing monomer.

[0049] The wave-absorbing agent, heat-conducting powder, vinyl silicone oil, hydrogen-containing silicone oil, inhibitor, and catalyst are placed in a homogenizer and stirred and mixed. During the stirring process, the temperature of the material is controlled to be less than or equal to the curing temperature (e.g., 40 °C) to avoid the problem of cured dead material. After being mixed evenly, it is placed in a special mold for high-temperature curing and molding to obtain a wave-absorbing housing monomer; wherein, grooves are provided on the surface of the wave-absorbing housing monomer.

[0050] As described in step S120, the wave-absorbing agent, heat-conducting powder, and composite phase change matrix are stirred and mixed according to the ratio to obtain the phase change wave-absorbing material 20.

[0051] The wave-absorbing agent, heat-conducting powder, and composite phase change matrix are placed in an oven and baked at a first temperature (e.g., 50 °C) for 30 min to ensure that the material is in a semi-solid state for easy mixing. Then, it is placed in a homogenizer and stirred and mixed. During the mixing process, vacuum is pumped, and the temperature is controlled to be less than or equal to the second temperature (e.g., 60 °C) to avoid unnecessary phase change losses, thereby obtaining the phase change wave-absorbing material 20.

[0052] As described in step S130, the phase change wave-absorbing material 20 is filled into the grooves inside the wave-absorbing housing monomer.

[0053] The phase change wave-absorbing material 20 is poured into the grooves inside the wave-absorbing housing monomer while it is hot to ensure that the surface of the wave-absorbing housing monomer is filled smoothly.

[0054] As described in step S140, two wave-absorbing housing monomers filled with the phase change wave-absorbing material 20 are butted and bonded with an adhesive to obtain a phase change wave-absorbing gasket.

[0055] Two wave-absorbing housing monomers filled with the phase change wave-absorbing material 20 are butted and bonded with an organosilicon adhesive to obtain a phase change wave-absorbing gasket.

[0056] Example 1

[0057] A variable-frequency phase-change wave-absorbing gasket, comprising: a solid wave-absorbing housing and a phase-change wave-absorbing material filled at the central position inside the solid wave-absorbing housing; the length and width of the solid wave-absorbing housing are both 10 cm, and the height is 2 cm; the length and width of the phase-change wave-absorbing material are both 5 cm, and the height is 1 cm;

[0058] The solid wave-absorbing housing comprises the following raw materials by mass parts: 70 parts of carbonyl iron, 20 parts of alumina, 3 parts of zinc oxide, 5.8 parts of vinyl silicone oil, 1 part of hydrogen-containing silicone oil, 0.18 part of platinum catalyst, and 0.02 part of ethynylcyclohexanol;

[0059] The phase-change wave-absorbing material comprises the following raw materials by mass parts: 20 parts of carbonyl iron, 10 parts of iron-nickel-cobalt-titanium alloy, 1 part of expanded graphite, 11 parts of β-silicon carbide, 50 parts of alumina, 5 parts of paraffin, 1 part of polyol, and 2 parts of polyisobutylene; wherein, the paraffin, the polyol, and the polyisobutylene form a composite phase-change matrix, and the phase-change points are 45 °C and 70 °C.

[0060] The preparation method of the phase-change wave-absorbing gasket comprises:

[0061] Placing wave-absorbing agents, heat-conducting powders, vinyl silicone oil, hydrogen-containing silicone oil, inhibitors, and catalysts in a homogenizer according to the ratio and stirring and mixing them. During the stirring process, control the temperature of the material body to be less than or equal to 40 °C to avoid the problem of curing dead materials. After mixing evenly, place them in a special mold and cure them at high temperature to form a single wave-absorbing housing; wherein, grooves are provided on the surface of the single wave-absorbing housing;

[0062] Placing wave-absorbing agents, heat-conducting powders, and the composite phase-change matrix in an oven and baking them at 50 °C for 30 min to ensure that the materials are in a semi-solid state for easy mixing. Then place them in a homogenizer and stir and mix them. During the mixing process, evacuate the air and control the temperature to be less than or equal to 60 °C to avoid unnecessary phase-change losses, and obtain the phase-change wave-absorbing material;

[0063] Pour the phase-change wave-absorbing material into the grooves inside the single wave-absorbing housing while it is hot to ensure that the surface of the single wave-absorbing housing is filled smoothly;

[0064] Adopt an organosilicon adhesive to buckle and bond two single wave-absorbing housings filled with the phase-change wave-absorbing material to obtain the phase-change wave-absorbing gasket.

[0065] Example 2

[0066] A variable-frequency phase-change wave-absorbing gasket, comprising: a solid wave-absorbing housing and a phase-change wave-absorbing material filled at the central position inside the solid wave-absorbing housing; the length and width of the solid wave-absorbing housing are both 10 cm, and the height is 2 cm; the length and width of the phase-change wave-absorbing material are both 5 cm, and the height is 1 cm;

[0067] The solid-state wave-absorbing housing includes the following raw materials by mass fraction: 70 parts of carbonyl iron, 20 parts of alumina, 3 parts of zinc oxide, 5.8 parts of vinyl silicone oil, 1 part of hydrogen-containing silicone oil, 0.18 part of platinum catalyst, and 0.02 part of ethynylcyclohexanol;

[0068] The phase-change wave-absorbing material includes the following raw materials by mass fraction: 20 parts of carbonyl iron, 10 parts of iron-nickel-cobalt-titanium alloy, 1 part of expanded graphite, 11 parts of β-silicon carbide, 50 parts of alumina, 5 parts of paraffin wax, and 3 parts of phase-change microcapsules; wherein, the paraffin wax and the phase-change microcapsules form a composite phase-change matrix with phase-change points of 42 °C and 75 °C.

[0069] The preparation method of the phase-change wave-absorbing gasket is the same as that of Example 1.

[0070] Example 3

[0071] A frequency-variable phase-change wave-absorbing gasket includes: a solid-state wave-absorbing housing and a phase-change wave-absorbing material filled in the central position inside the solid-state wave-absorbing housing; the length and width of the solid-state wave-absorbing housing are both 10 cm, and the height is 2 cm; the length and width of the phase-change wave-absorbing material are both 5 cm, and the height is 1 cm;

[0072] The solid-state wave-absorbing housing includes the following raw materials by mass fraction: 35 parts of carbonyl iron, 38 parts of silicon carbide, 20 parts of alumina, 5.8 parts of vinyl silicone oil, 1 part of hydrogen-containing silicone oil, 0.18 part of platinum catalyst, and 0.02 part of ethynylcyclohexanol;

[0073] The phase-change wave-absorbing material includes the following raw materials by mass fraction: 20 parts of carbonyl iron, 10 parts of indium-bismuth alloy, 1 part of expanded graphite, 11 parts of β-silicon carbide, 50 parts of alumina, 5 parts of paraffin wax, and 3 parts of phase-change microcapsules; wherein, the paraffin wax and the phase-change microcapsules form a composite phase-change matrix with phase-change points of 42 °C and 75 °C.

[0074] The preparation method of the phase-change wave-absorbing gasket is the same as that of Example 1.

[0075] Comparative Example 1

[0076] A phase-change wave-absorbing gasket includes: a solid-state wave-absorbing housing; the length and width of the solid-state wave-absorbing housing are both 10 cm, and the height is 2 cm;

[0077] The solid-state wave-absorbing housing includes the following raw materials by mass fraction: 70 parts of carbonyl iron, 20 parts of alumina, 3 parts of zinc oxide, 5.8 parts of vinyl silicone oil, 1 part of hydrogen-containing silicone oil, 0.18 part of platinum catalyst, and 0.02 part of ethynylcyclohexanol.

[0078] The preparation method of the phase-change wave-absorbing gasket includes:

[0079] Mix the microwave absorber, thermal conductive powder, vinyl silicone oil, hydrogen-containing silicone oil, inhibitor and catalyst in a homogenizer according to the ratio. During the stirring process, control the temperature of the material to be less than or equal to 40 °C to avoid the problem of solidified dead materials. After mixing evenly, place it in a mold and cure it at high temperature to obtain a solid microwave-absorbing housing.

[0080] Test the microwave absorption performance of Comparative Example 1 and Examples 1 to 3 at 25 °C, 50 °C and 80 °C respectively. The results are shown in Table 1.

[0081] Table 1 Microwave absorption performance test results of Comparative Example 1 and Examples 1 to 3

[0082]

[0083] It can be seen from the data in Table 1 that in Comparative Example 1, regardless of whether it is at 25 °C, 50 °C or 80 °C, the microwave absorption peak always remains at 6 GHz @ -18 dB, and the microwave absorption band always remains at 5.2 - 6.8 GHz, and the microwave absorption performance has no significant change; while in Examples 1 to 3, at 50 °C and 80 °C, compared with 25 °C, additional microwave absorption peaks appear, and the microwave absorption band is also significantly broadened, showing a wider microwave absorption ability.

[0084] In summary, the phase change microwave absorption gasket of the present application can perform multi-stage phase change through temperature change, significantly improving the ability to absorb electromagnetic waves.

[0085] The above embodiments are all described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same and similar parts between the embodiments, reference can be made to each other.

[0086] Although the preferred embodiments of the present application have been described, once those skilled in the art learn the basic creative concepts, additional changes and modifications can be made to these embodiments. Therefore, the interpretation of the appended claims includes the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present application.

[0087] Finally, it should also be noted that in this specification, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or terminal device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or terminal device. Without further limitation, an element defined by the statement "comprising one..." does not exclude the existence of additional identical elements in the process, method, article or terminal device comprising the said element.

[0088] The above has introduced in detail a variable-frequency phase-change wave-absorbing gasket and its preparation method provided by the present application. Specific embodiments are used in this specification to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A frequency-variable phase-change absorbing pad, characterized in that: include: A solid-state absorbing shell and a phase-change absorbing material filled inside the solid-state absorbing shell; The phase change absorbing material comprises the following raw materials by weight: 30-60 parts of absorber, 40-70 parts of thermal conductive powder and 5-15 parts of composite phase change matrix; wherein the composite phase change matrix has more than two phase change points.

2. The phase change absorbing pad according to claim 1, characterized in that: The first phase change point of the composite phase change matrix is ​​40-50°C, and the second phase change point is 65-75°C.

3. The phase change absorbing pad according to claim 1, characterized in that: The composite phase change matrix includes at least two of paraffin wax, phase change microcapsules, polyols, polyethylene glycol and stearic acid.

4. The phase change absorbing pad according to claim 1, characterized in that: The solid-state wave-absorbing shell comprises the following raw materials by mass: 60-80 parts of wave-absorbing agent, 20-30 parts of thermal conductive powder, 3-7 parts of vinyl silicone oil, 0.5-2 parts of hydrogen-containing silicone oil, 0.1-0.5 parts of catalyst and 0.01-0.05 parts of inhibitor.

5. The phase change absorbing pad according to claim 1 or 4, characterized in that: The wave absorbing agent comprises at least one of carbonyl iron powder, acetylene black, ferrite, silicon carbide, expanded graphite, iron-platinum alloy, iron-nickel-cobalt-titanium alloy and nickel-manganese-based Heusler alloy.

6. The phase change absorbing pad according to claim 1 or 4, characterized in that: The thermally conductive powder includes at least one of aluminum oxide, zinc oxide, copper powder, silver powder, indium bismuth alloy and Cerrolow-136 alloy.

7. The phase change absorbing pad according to claim 4, characterized in that: The catalyst is a platinum catalyst.

8. The phase change absorbing pad according to claim 4, characterized in that: The inhibitor is an acetylene cyclohexanol inhibitor.

9. A method for preparing a phase change absorbing pad according to any one of claims 1 to 8, characterized in that: include: The wave absorbing agent, thermal conductive powder, vinyl silicone oil, hydrogen-containing silicone oil, inhibitor and catalyst are stirred and mixed according to the proportion, and placed in a mold for curing treatment to obtain a wave absorbing shell monomer; wherein the surface of the wave absorbing shell monomer is provided with a groove; The microwave absorbing agent, the thermal conductive powder and the composite phase change matrix are stirred and mixed according to a ratio to obtain a phase change microwave absorbing material; Filling the phase change absorbing material into the groove of the absorbing shell unit; Adhesive is used to butt-bond two absorbing shell monomers filled with the phase-change absorbing material to obtain a phase-change absorbing gasket.

10. The preparation method according to claim 9, characterized in that: The adhesive is a silicone adhesive.

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