High-temperature-resistant silicone rubber low-frequency wave-absorbing material and preparation method thereof

Abstract

The invention relates to the field of wave-absorbing materials, and particularly discloses a high-temperature-resistant silicone rubber low-frequency wave-absorbing material and a preparation method thereof. Comprising the following raw materials in parts by weight: 50-90 parts of diphenylmethane bismaleimide modified silicone rubber, 15-30 parts of silicon carbide, 10-12 parts of barium titanate, 10-12 parts of carbon nanotubes, 5-25 parts of conductive carbon black, 5-20 parts of graphite, 5-15 parts of silicon nitride, 5-10 parts of aluminum hydroxide and 3-5 parts of a vulcanizing agent. The wave-absorbing material disclosed by the invention is good in wave-absorbing performance and good in high-temperature resistance.

Description

Technical Field

[0001] The present application relates to the field of absorbing materials, and more specifically, to a high temperature resistant silicone rubber low frequency absorbing material and a preparation method thereof. Background Art

[0002] Absorbing materials refer to materials that can absorb electromagnetic waves, including absorbing fillers and substrates. Ultra-low frequency noise suppression sheets use the principle of reflection to shield electromagnetic noise, but the reflected electromagnetic waves will not only interfere with the operation of surrounding components, but also when the noise is reflected on the surface of the suppression sheet, electromagnetic eddy currents will be formed near its edge. This effect cannot be eliminated, so there will still be a small amount of noise that affects the operation of the protected components, and a small amount of electromagnetic noise will penetrate the suppression sheet. This phenomenon will gradually appear as the signal increases. Therefore, the absorbing noise suppression sheet is more suitable for use in precision electronic components; and the current absorbing materials are mainly in a dilemma between "lightness and high absorption". The magnetic material filling amount is large, the absorbing effect is good, but the mechanical strength is deteriorated: the tensile strength and softness are reduced; at the same time, because the absorbing materials are often used around electronic devices, there are higher requirements for the high temperature resistance of the absorbing materials, and silicone rubber will be thermally aged and degraded or become hard and brittle at high temperatures, and debond with the absorbing filler, resulting in the electromagnetic waves cannot be completely absorbed. Therefore, the development of an absorbing material that still has high absorption performance at high temperatures has a high market value. Summary of the invention

[0003] In order to solve the above problems, the present application provides a high temperature resistant silicone rubber low frequency absorbing material and a preparation method thereof.

[0004] In a first aspect, the present application provides a high temperature resistant silicone rubber low frequency absorbing material, comprising the following raw materials in parts by weight: 50-90 parts of diphenylmethane bismaleimide modified silicone rubber, 15-30 parts of silicon carbide, 10-12 parts of barium titanate, 10-12 parts of carbon nanotubes, 5-25 parts of conductive carbon black, 5-20 parts of graphite, 5-15 parts of silicon nitride, 5-10 parts of aluminum hydroxide, and 3-5 parts of vulcanizing agent.

[0005] By adopting the above technical scheme, diphenylmethane bismaleimide-modified silicone rubber is used as the substrate. After the silicone rubber is modified with diphenylmethane bismaleimide, it may be because the excess hydroxyl groups are consumed at this time, the moisture generated by the condensation of active hydroxyl groups and adsorbed water is reduced, the temperature resistance is improved to a certain extent, and the degradation of the main chain is reduced. Two phenyl groups and two maleimide groups are introduced to improve the main chain and side group structure of the silicone rubber, form a certain steric hindrance, and reduce the polar attack on the silicon-oxygen bond. The main chain of the silicone rubber obtained becomes less prone to thermal rearrangement and degradation, and because of its greater conjugation effect and steric hindrance effect, the thermal decomposition temperature is higher, and the side group is less likely to be oxidized at high temperature. The obtained absorbing material can maintain a relatively tight structure at high temperature, and low-frequency waves can better enter the absorbing material, further improving the temperature resistance. With the cooperation of a variety of absorbing fillers, the absorbing material can effectively absorb and disperse under the complex path inside the absorbing material, absorb electromagnetic waves through dielectric polarization and relaxation loss, and have a good absorbing effect.

[0006] In a specific embodiment, the preparation steps of diphenylmethane bismaleimide modified silicone rubber include: adding phthalate silane coupling agent to silicone rubber, stirring evenly, reacting, then adding diphenylmethane bismaleimide, stirring evenly, reacting, and drying to obtain diphenylmethane bismaleimide modified silicone rubber.

[0007] By adopting the above technical solution, the preparation method is relatively simple, and the surface of the prepared silicone rubber is more evenly distributed with diphenylmethane bismaleimide, which improves the temperature resistance of the material.

[0008] In a specific embodiment, the mass ratio of silicone rubber to diphenylmethane bismaleimide is 1:(0.8-0.9).

[0009] By adopting the above technical scheme, the linking effect of silicone rubber and diphenylmethane bismaleimide is good. At the same time, the phenyl groups introduced into the silicone rubber are relatively uniform and the quantity is appropriate. The introduction of too many phenyl groups will not make the obtained absorbing material too rigid, nor will too few phenyl groups limit the improvement of high temperature resistance. The obtained absorbing material has better tolerance under low-frequency waves.

[0010] In a specific embodiment, the silicone rubber includes methylphenyl silicone rubber and methylvinyl silicone rubber, and the mass ratio of the methylphenyl silicone rubber to the methylvinyl silicone rubber is 1:(0.8-0.9).

[0011] By adopting the above technical scheme, silicone rubber has the advantages of both methylphenyl silicone rubber and methylvinyl silicone rubber, the rigidity is not too large, and the compatibility with other components is good. At the same time, the maleimide group is electrophilic and can undergo electrophilic addition with methylvinyl silicone rubber. The cross-linking structure inside the absorbing material obtained by the addition of the two is more uniform and complex, the temperature resistance is better, and it still has excellent absorbing performance at high temperatures.

[0012] In a specific embodiment, the silicon carbide is vinyl silane modified silicon carbide whiskers.

[0013] By adopting the above technical scheme, silicon carbide whiskers have fewer defects and have quite good high temperature resistance, dielectric properties and strength. By adding silicon carbide whiskers, single crystal fibers are interspersed inside the absorbing material, so that the components are more closely combined, and electromagnetic waves are better absorbed after entering. After modification with vinyl silane, the distribution in the absorbing material is more uniform and stable, and it can also participate in cross-linking with diphenylmethane bismaleimide modified silicone rubber, further optimizing the cross-linking structure of the obtained absorbing material, and the obtained absorbing material has better high temperature resistance.

[0014] In a specific embodiment, the particle size of the silicon carbide whiskers is 50-100 nm.

[0015] By adopting the above technical solution, the whiskers are distributed more evenly in the absorbing material, which greatly improves the strength and high temperature resistance of the absorbing material. A better absorbing network is also constructed, and the absorbing performance is also greatly improved.

[0016] In a specific embodiment, the preparation steps of vinyl silane modified silicon carbide whiskers include: adding silicon carbide whiskers to ethanol aqueous solution, then adding vinyl silane coupling agent, stirring evenly, heating to react, filtering, washing, and drying to obtain vinyl silane modified silicon carbide whiskers.

[0017] By adopting the above technical solution, the preparation method is relatively simple, does not introduce a large number of impurities and redundant groups, and further reduces the thermal oxidation aging of the absorbing material.

[0018] In a second aspect, the present application provides a method for preparing a high temperature resistant silicone rubber low frequency absorbing material, characterized in that the preparation method comprises the following steps: S1: Weigh each component by weight, mix, and stir evenly to obtain a mixture; S2: The mixed material is milled at 120℃-135℃ for 8-10 minutes to obtain an intermediate rubber material; S3: The intermediate rubber material is allowed to stand for 20-24 hours, and then re-milled at 120℃-130℃ for 15-18 minutes to obtain a rubber material; S4: The rubber material obtained in S3 is heated at 12-15N / mm 2The absorbing sheet is rolled under a pressure of to obtain a absorbing thin sheet; S5: the absorbing thin sheet is compression molded to obtain a absorbing material.

[0019] By adopting the above technical scheme, the preparation method is relatively simple, the components are evenly distributed in the silicone rubber, the surface of the prepared silicone rubber is relatively flat and smooth, electromagnetic waves can enter and be absorbed better, the wave transmittance is good, the electromagnetic waves entering can be better scattered, and the millimeter waves are better absorbed.

[0020] In a specific embodiment, the mixture in S1 is further subjected to ultrasonic dispersion for 25-30 minutes at a power of 500-600W.

[0021] By adopting the above technical solution, the distribution of the mixed material is more uniform and stable, and the obtained absorbing material has better absorbing performance.

[0022] In summary, this application has the following beneficial effects: 1. The present application uses a variety of absorbers together and limits them to a certain mass ratio, and adopts a certain mass of diphenylmethane bismaleimide modified silicone rubber as a substrate, which consumes hydroxyl groups, increases steric protection, improves segment structure, and works together to reduce the degradation of silicone rubber at high temperatures, thereby improving the structural stability of the absorbing material so that it maintains a high absorbing ability at high temperatures.

[0023] 2. This application limits the silicone rubber to a certain mass ratio of methylphenyl silicone rubber and methylvinyl silicone rubber, limits the particle size of vinyl silane-modified silicon carbide whiskers, optimizes the cross-linking network of the absorbing material, and further improves the high temperature resistance of the absorbing material. DETAILED DESCRIPTION

[0024] To further help understand the technical solution of the present invention, several specific embodiments are provided to describe the technical solution of the present invention in more detail. All the embodiments described are only partial embodiments of the present invention, not all of them; the embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments. The following embodiments are further explanations of the present invention, and the present invention is not limited thereto.

[0025] Unless otherwise specified, the experimental reagents in the preparation examples, embodiments and comparative examples in this application are all conventional commercial brands or obtained through conventional preparation processes.

[0026] Preparation Example Preparation Example 1: Diphenylmethane bismaleimide modified silicone rubber: Add 300g of 1wt% phthalate silane coupling agent aqueous solution to 100g of methylphenyl silicone rubber, stir evenly, react at 75°C, then add 85g of diphenylmethane bismaleimide, stir evenly, react at 80°C, and dry to obtain diphenylmethane bismaleimide modified silicone rubber.

[0027] Preparation Example 2: Diphenylmethane bismaleimide modified silicone rubber: 300 g of 1 wt% phthalate silane coupling agent aqueous solution was added to 100 g of methylphenyl silicone rubber, stirred evenly, reacted at 75° C., and then 100 g of diphenylmethane bismaleimide was added, stirred evenly, reacted at 80° C., and dried to obtain diphenylmethane bismaleimide modified silicone rubber.

[0028] Preparation Example 3: Silicone rubber modified with vinyl silane coupling agent: 60 g of silane coupling agent KH-550 and 60 g of methylphenyl silicone rubber were added into 300 g of 80 wt % ethanol aqueous solution, mixed evenly, filtered and dried to obtain vinyl silane coupling agent modified silicone rubber.

[0029] Other commonly used preparation methods are all acceptable.

[0030] Preparation Example 4: Vinyl silane coupling agent modified silicon carbide whiskers: 60 g of silane coupling agent KH-550 and 60 g of silicon carbide whiskers were added into 300 g of 80 wt % ethanol aqueous solution, mixed evenly, filtered, and dried to obtain vinyl silane coupling agent modified silicon carbide whiskers.

[0031] The average particle size of the whiskers in this preparation example is 70 nm.

[0032] Other commonly used preparation methods are all acceptable.

[0033] Preparation Example 5: Diphenylmethane bismaleimide modified silicone rubber: 300 g of 1 wt% phthalate silane coupling agent aqueous solution was added to 100 g of methyl vinyl silicone rubber, stirred evenly, reacted at 75° C., then 85 g of diphenylmethane bismaleimide was added, stirred evenly, reacted at 80° C., and dried to obtain diphenylmethane bismaleimide modified silicone rubber. Example

[0034] Example 1 This example includes the following raw materials in mass: 500 g of diphenylmethane bismaleimide-modified silicone rubber obtained in Preparation Example 1, 150 g of silicon carbide, 100 g of barium titanate, 100 g of carbon nanotubes, 250 g of conductive carbon black, 100 g of graphite, 150 g of silicon nitride, 50 g of aluminum hydroxide, and 30 g of tert-butyl perbenzoate.

[0035] The preparation method is as follows: S1: Weigh each component by weight, mix, and stir evenly to obtain a mixture; S2: the mixed material was milled at 120℃ for 10 minutes to obtain an intermediate rubber compound; S3: the intermediate rubber compound was allowed to stand for 20 hours and then milled at 120℃ for 18 minutes to obtain a rubber compound; S4: the rubber compound obtained in S3 was heated at 12N / mm 2 The absorbing sheet is rolled under a pressure of to obtain a absorbing thin sheet; S5: the absorbing thin sheet is compression molded to obtain a absorbing material.

[0036] Example 2 This example includes the following raw materials: 900 g of diphenylmethane bismaleimide-modified silicone rubber obtained in Preparation Example 1, 200 g of silicon carbide, 100 g of barium titanate, 120 g of carbon nanotubes, 50 g of conductive carbon black, 100 g of graphite, 150 g of silicon nitride, 50 g of aluminum hydroxide, and 30 g of tert-butyl perbenzoate.

[0037] The preparation method is as follows: S1: Weigh each component by weight, mix, and stir evenly to obtain a mixture; S2: the mixed material was milled at 120℃ for 10 minutes to obtain an intermediate rubber compound; S3: the intermediate rubber compound was allowed to stand for 20 hours and then milled at 120℃ for 18 minutes to obtain a rubber compound; S4: the rubber compound obtained in S3 was heated at 12N / mm 2 The absorbing sheet is rolled under a pressure of to obtain a absorbing thin sheet; S5: the absorbing thin sheet is compression molded to obtain a absorbing material.

[0038] Example 3 This example includes the following raw materials in mass: 500 g of diphenylmethane bismaleimide-modified silicone rubber obtained in Preparation Example 1, 150 g of silicon carbide, 120 g of barium titanate, 120 g of carbon nanotubes, 250 g of conductive carbon black, 200 g of graphite, 150 g of silicon nitride, 100 g of aluminum hydroxide, and 50 g of tert-butyl perbenzoate.

[0039] The preparation method is as follows: S1: Weigh each component by weight, mix, and stir evenly to obtain a mixture; S2: the mixed material was milled at 120℃ for 10 minutes to obtain an intermediate rubber compound; S3: the intermediate rubber compound was allowed to stand for 20 hours and then milled at 120℃ for 18 minutes to obtain a rubber compound; S4: the rubber compound obtained in S3 was heated at 12N / mm 2 The absorbing sheet is rolled under a pressure of to obtain a absorbing thin sheet; S5: the absorbing thin sheet is compression molded to obtain a absorbing material.

[0040] Example 4 This example includes the following raw materials in mass: 500 g of diphenylmethane bismaleimide-modified silicone rubber obtained in Preparation Example 2, 150 g of silicon carbide, 100 g of barium titanate, 100 g of carbon nanotubes, 250 g of conductive carbon black, 100 g of graphite, 150 g of silicon nitride, 50 g of aluminum hydroxide, and 30 g of tert-butyl perbenzoate.

[0041] The preparation method is as follows: S1: Weigh each component by weight, mix, and stir evenly to obtain a mixture; S2: the mixed material was milled at 120℃ for 10 minutes to obtain an intermediate rubber compound; S3: the intermediate rubber compound was allowed to stand for 20 hours and then milled at 120℃ for 18 minutes to obtain a rubber compound; S4: the rubber compound obtained in S3 was heated at 12N / mm 2 The absorbing sheet is rolled under a pressure of to obtain a absorbing thin sheet; S5: the absorbing thin sheet is compression molded to obtain a absorbing material.

[0042] Example 5 This embodiment contains the following raw materials in mass: 277 g of diphenylmethane bismaleimide-modified silicone rubber prepared in Preparation Example 1, 223 g of diphenylmethane bismaleimide-modified silicone rubber prepared in Preparation Example 5, 150 g of silicon carbide, 100 g of barium titanate, 100 g of carbon nanotubes, 250 g of conductive carbon black, 100 g of graphite, 150 g of silicon nitride, 50 g of aluminum hydroxide, and 30 g of tert-butyl perbenzoate.

[0043] The preparation method is as follows: S1: Weigh each component by weight, mix, and stir evenly to obtain a mixture; S2: the mixed material was milled at 120℃ for 10 minutes to obtain an intermediate rubber compound; S3: the intermediate rubber compound was allowed to stand for 20 hours and then milled at 120℃ for 18 minutes to obtain a rubber compound; S4: the rubber compound obtained in S3 was heated at 12N / mm 2 The absorbing sheet is rolled under a pressure of to obtain a absorbing thin sheet; S5: the absorbing thin sheet is compression molded to obtain a absorbing material.

[0044] Example 6 This embodiment contains the following raw materials in mass: 250 g of diphenylmethane bismaleimide-modified silicone rubber prepared in Preparation Example 1, 250 g of diphenylmethane bismaleimide-modified silicone rubber prepared in Preparation Example 5, 150 g of silicon carbide, 100 g of barium titanate, 100 g of carbon nanotubes, 250 g of conductive carbon black, 100 g of graphite, 150 g of silicon nitride, 50 g of aluminum hydroxide, and 30 g of tert-butyl perbenzoate.

[0045] The preparation method is as follows: S1: Weigh each component by weight, mix, and stir evenly to obtain a mixture; S2: the mixed material was milled at 120℃ for 10 minutes to obtain an intermediate rubber compound; S3: the intermediate rubber compound was allowed to stand for 20 hours and then milled at 120℃ for 18 minutes to obtain a rubber compound; S4: the rubber compound obtained in S3 was heated at 12N / mm 2 The absorbing sheet is rolled under a pressure of to obtain a absorbing thin sheet; S5: the absorbing thin sheet is compression molded to obtain a absorbing material.

[0046] Example 7 This embodiment contains the following raw materials in mass: 277 g of diphenylmethane bismaleimide-modified silicone rubber prepared in Preparation Example 1, 223 g of diphenylmethane bismaleimide-modified silicone rubber prepared in Preparation Example 5, 150 g of vinyl silane coupling agent-modified silicon carbide whiskers prepared in Preparation Example 4, 100 g of barium titanate, 100 g of carbon nanotubes, 250 g of conductive carbon black, 100 g of graphite, 150 g of silicon nitride, 50 g of aluminum hydroxide, and 30 g of tert-butyl perbenzoate.

[0047] The preparation method is as follows: S1: Weigh each component by weight, mix, and stir evenly to obtain a mixture; S2: the mixed material was milled at 120℃ for 10 minutes to obtain an intermediate rubber compound; S3: the intermediate rubber compound was allowed to stand for 20 hours and then milled at 120℃ for 18 minutes to obtain a rubber compound; S4: the rubber compound obtained in S3 was heated at 12N / mm 2 The absorbing sheet is rolled under a pressure of to obtain a absorbing thin sheet; S5: the absorbing thin sheet is compression molded to obtain a absorbing material.

[0048] Comparative Example Comparative Example 1 This comparative example contains the following raw materials in mass: 500 g of the vinyl silane coupling agent modified silicone rubber obtained in Preparation Example 3, 150 g of silicon carbide, 100 g of barium titanate, 100 g of carbon nanotubes, 250 g of conductive carbon black, 100 g of graphite, 150 g of silicon nitride, 50 g of aluminum hydroxide, and 30 g of tert-butyl perbenzoate.

[0049] The preparation method is as follows: S1: Weigh each component by weight, mix, and stir evenly to obtain a mixture; S2: the mixed material was milled at 120℃ for 10 minutes to obtain an intermediate rubber compound; S3: the intermediate rubber compound was allowed to stand for 20 hours and then milled at 120℃ for 18 minutes to obtain a rubber compound; S4: the rubber compound obtained in S3 was heated at 12N / mm 2 The absorbing sheet is rolled under a pressure of to obtain a absorbing thin sheet; S5: the absorbing thin sheet is compression molded to obtain a absorbing material.

[0050] Comparative Example 2 This comparative example contains the following raw materials in mass: 400 g of diphenylmethane bismaleimide-modified silicone rubber obtained in Preparation Example 1, 150 g of silicon carbide, 150 g of barium titanate, 100 g of carbon nanotubes, 250 g of conductive carbon black, 100 g of graphite, 150 g of silicon nitride, 50 g of aluminum hydroxide, and 50 g of tert-butyl perbenzoate.

[0051] The preparation method is as follows: S1: Weigh each component by weight, mix, and stir evenly to obtain a mixture; S2: the mixed material was milled at 120℃ for 10 minutes to obtain an intermediate rubber compound; S3: the intermediate rubber compound was allowed to stand for 20 hours and then milled at 120℃ for 18 minutes to obtain a rubber compound; S4: the rubber compound obtained in S3 was heated at 12N / mm 2 The absorbing sheet is rolled under a pressure of to obtain a absorbing thin sheet; S5: the absorbing thin sheet is compression molded to obtain a absorbing material.

[0052] Performance test Test 1: An absorbing material of 150 mm × 150 mm × 2 mm size is set between the antennas of the KEC method evaluation device including a signal generator, an amplifier, a pair of magnetic field antennas and a spectrum analyzer, and the ratio of the received signal strength without the absorbing material to the received signal strength with the absorbing material at a frequency of 30-300 GHz is obtained as the absorbing capacity 1. KEC is the abbreviation of Kansai Electronic Industry Promotion Center. The test results are shown in Table 1.

[0053] Test 2: The absorbing materials of each embodiment were heated at 350°C for 24 hours, and the test 1 was repeated to test the absorbing capacity 2 of the absorbing materials. Then the absorbing capacity retention rate was calculated, and the reduction rate = absorbing capacity 2 / absorbing capacity 1 × 100%. The test results are shown in Table 1.

[0054] Table 1 It can be seen from Examples 1-3 and Comparative Example 2 and Table 1 that the absorbing material prepared in the present application has good absorbing ability and high temperature resistance.

[0055] It can be seen from Example 1, Examples 4-6, Comparative Example 1 and Table 1 that the absorbing material prepared in the present application has better absorbing ability and high temperature resistance by specifying special silicone rubber and limiting the mass ratio.

[0056] It can be seen from Example 1, Example 7 and Table 1 that the present application further optimizes the performance of the absorbing material by modifying the silicon carbide whiskers.

[0057] The specific embodiment adopted in this application is only an explanation of this application, and it is not a limitation of this application. After reading this specification, technical personnel in this field can make non-creative modifications to this embodiment as needed, but as long as it is within the scope of the claims of this application, it is protected by the patent law.

Claims

1. A high temperature resistant silicone rubber low frequency absorbing material, characterized by: The invention comprises the following raw materials in parts by weight: 50-90 parts of diphenylmethane bismaleimide modified silicone rubber, 15-30 parts of silicon carbide, 10-12 parts of barium titanate, 10-12 parts of carbon nanotubes, 5-25 parts of conductive carbon black, 5-20 parts of graphite, 5-15 parts of silicon nitride, 5-10 parts of aluminum hydroxide and 3-5 parts of vulcanizing agent.

2. The high temperature resistant silicone rubber low frequency absorbing material according to claim 1, characterized in that: The preparation steps of the diphenylmethane bismaleimide modified silicone rubber include: adding a phthalate silane coupling agent to the silicone rubber, stirring evenly, reacting, then adding diphenylmethane bismaleimide, stirring evenly, reacting, and drying to obtain the diphenylmethane bismaleimide modified silicone rubber.

3. The high temperature resistant silicone rubber low frequency absorbing material according to claim 2, characterized in that: The mass ratio of the silicone rubber to diphenylmethane bismaleimide is 1:(0.8-0.9).

4. The high temperature resistant silicone rubber low frequency absorbing material according to claim 1, characterized in that: The silicone rubber includes methylphenyl silicone rubber and methylvinyl silicone rubber, and the mass ratio of the methylphenyl silicone rubber to the methylvinyl silicone rubber is 1:(0.8-0.9).

5. The high temperature resistant silicone rubber low frequency absorbing material according to claim 4, characterized in that: The silicon carbide is vinyl silane modified silicon carbide whisker.

6. The high temperature resistant silicone rubber low frequency absorbing material according to claim 5, characterized in that: The particle size of the silicon carbide whisker is 50-100 nm.

7. The high temperature resistant silicone rubber low frequency absorbing material according to claim 5, characterized in that: The steps of preparing the vinyl silane modified silicon carbide whisker include: adding the silicon carbide whisker into an ethanol aqueous solution, then adding a vinyl silane coupling agent, stirring evenly, heating for reaction, filtering, washing, and drying to obtain the vinyl silane modified silicon carbide whisker.

8. A method for preparing the high temperature resistant silicone rubber low frequency absorbing material according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: S1: Weigh each component by weight, mix, and stir evenly to obtain a mixture; S2: The mixed material is milled at 120℃-135℃ for 8-10 minutes to obtain an intermediate rubber material; S3: The intermediate rubber material is allowed to stand for 20-24 hours, and then re-milled at 120℃-130℃ for 15-18 minutes to obtain a rubber material; S4: The rubber material obtained in S3 is heated at 12-15N / mm 2 The absorbing sheet is rolled under a pressure of to obtain a absorbing thin sheet; S5: the absorbing thin sheet is compression molded to obtain a absorbing material.

9. The method for preparing a high temperature resistant silicone rubber low frequency absorbing material according to claim 8, characterized in that: The mixture in S1 is further subjected to ultrasonic dispersion for 25-30 minutes at a power of 500-600W.

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