Wave-absorbing agent suitable for 5G base station shielding material and preparation method of wave-absorbing agent

Abstract

The invention relates to the technical field of electromagnetic wave absorbing materials, in particular to a wave absorbing agent suitable for a 5G base station shielding material and a preparation method of the wave absorbing agent. The preparation method of the wave-absorbing agent comprises the following steps: mixing carbonyl iron powder and a dielectric material, then carrying out three-stage ball milling, and then carrying out annealing treatment to obtain the wave-absorbing agent, the three-stage ball milling is specifically as follows: stage 1: the ball-to-material ratio is 10: 1, the rotating speed is 300-350 rpm, and the time is 2 hours; stage 2: the ball-to-material ratio is (20-25): 1, the rotating speed is 600-700 rpm, and the time is 3.5-5 h; and stage 3, adding an additive accounting for 1% of the total mass of the carbonyl iron powder and the dielectric material, and then carrying out ball milling in the stage 3, with the ball-to-material ratio being 5: 1, the rotating speed being 200-250 rpm and the time being 1 h. According to the invention, a staged ball-milling process is adopted to realize morphology regulation and control of wave-absorbing agent particles, so that the wave-absorbing capacity of the wave-absorbing agent at a P wave band below 1GHz is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic wave absorbing materials, and in particular to a wave absorbing agent suitable for 5G base station shielding materials and a preparation method thereof. Background Art

[0002] Carbonyl iron powder is one of the commonly used absorbing materials because of its high magnetic permeability and adjustable dielectric constant. However, the carbonyl iron powder absorbers currently on the market usually work in the 1GHz-18GHz frequency band. From the current commonly used communication frequency band, it can be seen that the low-frequency end has extended to 700MHz. In order to expand the working frequency band of the absorbing material, the commonly used technical means is to compound carbonyl iron powder with other absorbers. For example, Chinese invention patent CN114899618B discloses a 700MHz 5G base station absorbing patch in the P band and a preparation method, which is made of a ternary magnetic composite absorber and rubber; wherein the ternary magnetic composite absorber includes secondary sintered ferrite, flaky carbonyl iron and flaky iron silicon aluminum; the secondary sintered ferrite includes ferric oxide, zinc oxide, cobalt oxide and barium carbonate; its preparation process is complicated, which is not conducive to large-scale production, and the thickness is relatively thick and the efficiency needs to be improved.

[0003] Therefore, providing an absorbent suitable for 5G base station shielding materials with a simple preparation process, simple component composition, and wave absorbing capability in the P band below 1 GHz is of great significance to the technical field of electromagnetic wave absorbing materials. Summary of the invention

[0004] Based on the above content, the present invention provides an absorbent suitable for 5G base station shielding materials and a preparation method thereof. The absorbent is used to prepare an absorbing material, which can achieve strong absorption of 5G base station electromagnetic radiation around 700MHz; the preparation method of the present invention is simple and environmentally friendly.

[0005] To achieve the above object, the present invention provides the following solutions: One of the technical solutions of the present invention is a method for preparing a wave absorbing agent suitable for 5G base station shielding materials, comprising the following steps: The carbonyl iron powder is mixed with the dielectric material and subjected to three-stage ball milling, followed by annealing to obtain the absorbent; The three-stage ball milling is specifically as follows: Stage 1: ball-to-material ratio is 10:1, rotation speed is 300-350 rpm, and time is 2 h; Stage 2: ball-to-material ratio is (20-25):1, speed is 600-700 rpm, and time is 3.5-5 h; Stage 3: After adding additives accounting for 1% of the total mass of carbonyl iron powder and dielectric material, stage 3 ball milling was carried out, with a ball-to-material ratio of 5:1, a rotation speed of 200-250 rpm, and a time of 1 h.

[0006] The second technical solution of the present invention is the wave absorbing agent prepared according to the above-mentioned preparation method.

[0007] The third technical solution of the present invention is the application of the above-mentioned absorber in the preparation of 5G base station shielding materials.

[0008] The fourth technical solution of the present invention is a 5G base station shielding material, the raw materials of which include the above-mentioned absorber.

[0009] A fifth technical solution of the present invention is a method for preparing the above-mentioned 5G base station shielding material, which comprises mixing the absorber with the rubber, and then performing internal mixing, open mixing, sheeting, and vulcanization in sequence to obtain the 5G base station shielding material.

[0010] The present invention discloses the following technical effects: The present invention provides a method for preparing an absorber suitable for 5G base station shielding materials by high-energy ball milling. A staged ball milling process is adopted to achieve morphology control of the absorber particles, thereby improving the absorber's absorbing ability in the P band below 1 GHz.

[0011] The absorber prepared by the method of the present invention has significantly improved magnetic permeability in the low frequency band below 1 GHz, with the real part of the magnetic permeability being greater than 7 and the imaginary part of the magnetic permeability being greater than 2, and can be effectively used for electromagnetic shielding of 5G base stations. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0013] Figure 1 This is a SEM image of the absorber prepared in Comparative Example 1 of the present invention.

[0014] Figure 2 This is a SEM image of the absorber prepared in Example 2 of the present invention.

[0015] Figure 3 This is a particle size distribution diagram of the absorber prepared in Example 2 of the present invention. DETAILED DESCRIPTION

[0016] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0017] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0018] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0019] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0020] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0021] The "%" mentioned in the present invention, unless otherwise specified, refers to mass percentage.

[0022] A first aspect of the present invention provides a method for preparing a wave absorbing agent suitable for a 5G base station shielding material, comprising the following steps: The carbonyl iron powder and the dielectric material are mixed and then subjected to three-stage ball milling (argon or nitrogen is filled for protection during the ball milling process, and the gas flow rate is 0.5-1.5 L / min), followed by annealing to obtain the absorbent; The three-stage ball milling is specifically as follows: Stage 1: The ball-to-material ratio is 10:1, the rotation speed is 300-350 rpm, and the time is 2 h. The main function of stage 1 is to crush large particles. Stage 2: The ball-to-material ratio is (20-25):1, the rotation speed is 600-700 rpm, and the time is 3.5-5 h; the main function of stage 2 is to form a flake structure; Stage 3: After adding additives accounting for 1% of the total mass of carbonyl iron powder and dielectric material, stage 3 ball milling is carried out, with a ball-to-material ratio of 5:1, a rotation speed of 200-250 rpm, and a time of 1 h; the main function of stage 3 is surface activation.

[0023] The present invention realizes the "crushing-flattening-surface activation" graded treatment by regulating the rotation speed, ball-to-material ratio and time of ball milling in stages, thereby realizing the absorbing ability of the absorber for the P band below 1 GHz (about 700 MHz).

[0024] In a preferred embodiment of the present invention, the mass ratio of the carbonyl iron powder to the dielectric material is (3-10):1, and more preferably (5-8):1; the dielectric material is carbon nanotubes.

[0025] In a preferred embodiment of the present invention, hard stainless steel grinding balls (hardness HRC 60) are used, and Φ8 mm grinding balls (70%) + Φ10 mm grinding balls (30%) are used in stage 1; Φ8 mm grinding balls (50%) + Φ5 mm grinding balls (50%) are used in both stage 2 and stage 3.

[0026] In a preferred embodiment of the present invention, the additive is stearic acid and / or a silane coupling agent.

[0027] In a preferred embodiment of the present invention, the annealing treatment adopts overall annealing or segmented annealing; the overall annealing is specifically: annealing at 200~400℃ for 1~3 hours under a protective atmosphere; the segmented annealing is specifically: under a protective atmosphere, first keep the temperature at 200℃ for 1 hour, then heat to 300℃ in 1 hour, keep the temperature for 2 hours, and then heat to 400℃ in 1 hour and keep the temperature for 1 hour.

[0028] The protective atmosphere is argon, or a mixed atmosphere of argon and hydrogen with a hydrogen content of 1-5 vol%.

[0029] A second aspect of the present invention provides a wave absorbing agent prepared according to the above-mentioned preparation method.

[0030] A third aspect of the present invention provides the use of the above-mentioned absorber in the preparation of 5G base station shielding materials.

[0031] A fourth aspect of the present invention provides a 5G base station shielding material, the raw materials of which include the above-mentioned absorber.

[0032] A fifth aspect of the present invention provides a method for preparing the above-mentioned 5G base station shielding material, wherein the absorber is mixed with the rubber, and then the mixture is subjected to internal mixing, open mixing, sheeting, and vulcanization in sequence to obtain the 5G base station shielding material.

[0033] The present invention does not impose any particular limitation on the conditions for internal mixing, open mixing, sheeting and high temperature plate vulcanization, and the conditions for internal mixing, open mixing, sheeting and high temperature plate vulcanization well known to those skilled in the art may be used.

[0034] In a preferred embodiment of the present invention, the mass ratio of the absorber to the rubber is 73:27.

[0035] The absorbing material prepared using the absorber of the present invention can achieve strong absorption of electromagnetic radiation around 700 MHz and can be used as a 5G base station shielding material.

[0036] The technical solutions described in the present invention, unless otherwise specified, are all conventional solutions in the art, and the reagents or raw materials used, unless otherwise specified, are purchased from commercial channels or have been disclosed.

[0037] The carbonyl iron powder used in the embodiments of the present invention is spherical with a particle size of 1-5 μm, purchased from Jiangsu Tianyi Ultrafine Metal Powder Co., Ltd.; the carbon nanotubes are purchased from Beijing Dekedaojin Technology Co., Ltd. with a tube diameter of 1-2 nm and a length of 5-30 μm.

[0038] The silane coupling agent used in the embodiment of the present invention is a conventional model KH560 purchased from Nanjing Chengong Organic Silicone Material Co., Ltd.; the rubber used in the embodiment of the present invention is specifically methyl vinyl silicone rubber (PDMS is also applicable to the present invention).

[0039] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0040] Example 1

[0041] Step 1: Mix carbonyl iron powder and carbon nanotubes in a mass ratio of 6:1, and then perform three-stage ball milling (argon gas protection is used during the ball milling process, and the gas flow rate is 1.0 L / min): Stage 1 (coarse grinding): ball-to-material ratio 10:1, speed 300 rpm, time 2 h; Stage 2 (fine grinding): ball-to-material ratio 20:1, speed 600 rpm, time 4 h; Stage 3 (surface modification): adding stearic acid and silane coupling agent (mass ratio of stearic acid to silane coupling agent is 1:1) accounting for 1% of the total mass of carbonyl iron powder and carbon nanotubes, ball-to-material ratio of 5:1, rotation speed of 200 rpm, time of 1 h.

[0042] Hard stainless steel grinding balls (hardness HRC 60) are used to provide high impact energy and reduce pollution; Φ8 mm grinding balls (70%) + Φ10 mm grinding balls (30%) are used in stage 1; Φ8 mm grinding balls (50%) + Φ5 mm grinding balls (50%) are used in both stage 2 and stage 3. Larger grinding balls are used in stage 1 to increase the collision energy density; smaller grinding balls are used in subsequent stages to increase the collision frequency and refine the surface structure.

[0043] Step 2, annealing treatment: after the ball milling is completed, annealing is performed at 300° C. for 2 h, the protective atmosphere is argon containing 3 vol% hydrogen, and the absorber is obtained after the annealing is completed.

[0044] The absorber prepared in this embodiment has high integrity of sheet structure and strong surface activity. The absorber and paraffin are melted in a mass ratio of 83:17 to form a ring test piece, and the real part of the magnetic permeability of the ring test piece in the low frequency band below 1 GHz is measured by a vector network analyzer and a coaxial air transmission line. The imaginary part of the magnetic permeability is greater than 7 and the imaginary part of the magnetic permeability is greater than 2.

[0045] The absorbent prepared in Example 1 and the rubber were mixed in a mass ratio of 73:27, and subjected to internal mixing, open mixing, sheeting, and high-temperature plate vulcanization to obtain a flat plate-shaped absorbent material. The internal mixing time was 15 minutes, the open mixing time was 60 minutes, the vulcanization temperature was 150° C., the vulcanization time was 15 minutes, and the plate test sample size was 800*800 mm and the thickness was 3.0 mm. The reflection loss of the prepared flat plate-shaped absorbent material to 700 MHz electromagnetic waves was ≤-10 dB.

[0046] Example 2

[0047] Step 1: Mix carbonyl iron powder and carbon nanotubes in a mass ratio of 7:1, and then perform three-stage ball milling (argon gas protection is used during the ball milling process, and the gas flow rate is 1.0 L / min): Stage 1: ball-to-material ratio 10:1, rotation speed 350 rpm, time 2 h; Stage 2: ball-to-material ratio 25:1, rotation speed 650 rpm, time 3.5 h; Stage 3: Add stearic acid accounting for 1% of the total mass of carbonyl iron powder and carbon nanotubes, ball-to-material ratio 5:1, rotation speed 250 rpm, time 1 h.

[0048] Hard stainless steel grinding balls (hardness HRC 60) were used. In stage 1, Φ8 mm grinding balls (70%) + Φ10 mm grinding balls (30%) were used; in stages 2 and 3, Φ8 mm grinding balls (50%) + Φ5 mm grinding balls (50%) were used.

[0049] Step 2, annealing treatment: after the ball milling is completed, annealing is performed at 350° C. for 1.5 h, the protective atmosphere is pure argon, and the absorber is obtained after the annealing is completed.

[0050] The SEM image of the absorber prepared in this example is as follows Figure 2 As shown by Figure 2 It can be seen that the flaky structure of the absorber is thinner and evenly distributed, with the flaky particles accounting for more than 90% and the thickness less than 200 nm. Figure 3 As shown by Figure 3 It can be seen that D50 = 4.880 microns, D90 = 8.486 microns, and the equivalent particle size measured is significantly larger than that of the raw material carbonyl iron powder, which is the result of ball milling. The absorber and paraffin are melted at a mass ratio of 83:17 to form a ring test piece. The real part of the magnetic permeability of the ring test piece in the low frequency band below 1GHz is measured by a vector network analyzer and a coaxial air transmission line. It is greater than 7, and the imaginary part of the magnetic permeability is greater than 2.

[0051] The absorbent prepared in Example 2 was used to prepare a flat-plate absorbing material in the same manner as in Example 1. The results showed that the absorbing band was broadened to 600-800 MHz, and the reflection loss of 600-800 MHz electromagnetic waves was ≤-10 dB.

[0052] Example 3

[0053] The only difference from Example 1 is that in step 1, the mass ratio of carbonyl iron powder to carbon nanotubes is 8:1; in step 2, the annealing treatment adopts segmented annealing: first, keep warm at 200°C for 1 h, then heat to 300°C in 1 hour and keep warm for 2 h, then heat to 400°C in 1 hour and keep warm for 1 h, and the protective atmosphere is argon containing 2 vol% hydrogen; the remaining steps and parameters are the same as in Example 1.

[0054] The absorber prepared in this embodiment and paraffin were melted at a mass ratio of 83:17 to form a ring-shaped test piece. The real part of the magnetic permeability of the ring-shaped test piece in the low frequency band below 1 GHz was measured by a vector network analyzer and a coaxial air transmission line, and the imaginary part of the magnetic permeability was greater than 7 and greater than 2. After annealing in the annealing method of Example 3, the crystallinity of the absorber was improved, and the thermal stability of the material was enhanced. The high and low temperature cycle test (reference standard GB / T 2423.22-2012) confirmed that the electromagnetic shielding performance can be maintained at an ambient temperature of 200°C.

[0055] Example 4

[0056] Step 1: Mix carbonyl iron powder and carbon nanotubes in a mass ratio of 5:1, and then perform three-stage ball milling (argon gas protection is used during the ball milling process, and the gas flow rate is 1.0 L / min): Stage 1: ball-to-material ratio 10:1, rotation speed 300 rpm, time 2 h; Stage 2: ball-to-material ratio 20:1, rotation speed 700 rpm, time 5 h; Stage 3: Add stearic acid accounting for 1% of the total mass of carbonyl iron powder and carbon nanotubes, ball-to-material ratio 5:1, rotation speed 200 rpm, time 1 h.

[0057] Hard stainless steel grinding balls (hardness HRC 60) were used. In stage 1, Φ8 mm grinding balls (70%) + Φ10 mm grinding balls (30%) were used; in stages 2 and 3, Φ8 mm grinding balls (50%) + Φ5 mm grinding balls (50%) were used.

[0058] Step 2, annealing treatment: after the ball milling is completed, annealing is performed at 400°C for 1 h, the protective atmosphere is argon containing 4 vol% hydrogen, and the absorber is obtained after the annealing is completed.

[0059] The thickness of the sheet structure of the absorber prepared in this embodiment is reduced to the nanometer level, with a thickness of less than 200nm. The absorber and paraffin are melted into a ring-shaped test piece in a mass ratio of 83:17. The real part of the magnetic permeability of the ring-shaped test piece in the low frequency band below 1GHz is measured by a vector network analyzer and a coaxial air transmission line. The real part of the magnetic permeability is greater than 7, and the imaginary part of the magnetic permeability is greater than 2; in the 1-3 GHz frequency band, the real part of the magnetic permeability is greater than 7, and the imaginary part of the magnetic permeability is greater than 2.5. The absorber of this embodiment is prepared into a 3.0mm thick flat plate-shaped absorbing material using the same method as in Example 1, and its reflection loss for 600MHz-3.2GHz electromagnetic waves is ≤-10dB.

[0060] Comparative Example 1 Step 1: Mix carbonyl iron powder and carbon nanotubes in a mass ratio of 6:1, and then perform two-stage ball milling (argon gas protection is used during the ball milling process, and the gas flow rate is 1.0 L / min): Stage 1 (rough grinding + surface modification): ball-to-material ratio 10:1, adding stearic acid and silane coupling agent (the mass ratio of stearic acid to silane coupling agent is 1:1) accounting for 1% of the total mass of carbonyl iron powder and carbon nanotubes, speed 300 rpm, time 2 h; Stage 2 (fine grinding): ball-to-grinding ratio 20:1, speed 600 rpm, time 4 h.

[0061] Hard stainless steel grinding balls (hardness HRC 60) were used. In stage 1, Φ8 mm grinding balls (70%) + Φ10 mm grinding balls (30%) were used; in stage 2, Φ8 mm grinding balls (50%) + Φ5 mm grinding balls (50%) were used.

[0062] Step 2, annealing treatment: after the ball milling is completed, annealing is performed at 300° C. for 2 h, the protective atmosphere is argon containing 3 vol% hydrogen, and the absorber is obtained after the annealing is completed.

[0063] The difference between this example and Example 1 is that the addition of the surface modifier in stage 3 of Example 1 is adjusted to stage 1 and the ball milling in stage 3 is omitted, and the steps are simplified compared with Example 1. The SEM image of the absorber obtained in this comparative example is as follows Figure 1 As shown. Figure 1 It can be seen that the integrity of the sheet structure is acceptable, but the size is uneven. The absorber and paraffin were melted in a mass ratio of 83:17 to make a ring test piece. The real part of the magnetic permeability of the ring test piece in the low frequency band below 1 GHz was measured using a vector network analyzer and a coaxial air transmission line. The imaginary part of the magnetic permeability is <7 and the imaginary part is <2.

[0064] Comparative Example 2 The only difference from Example 2 is that the addition of stearic acid in step 1 is omitted, and the remaining steps and parameters are the same as those in Example 2.

[0065] The absorber prepared in this comparative example was verified in the same way as in Example 2. The results showed that the particle size distribution became wider and the proportion of large-sized particles increased. The real part of the magnetic permeability of the annular test piece measured by a vector network analyzer and a coaxial air transmission line was <5 and the imaginary part of the magnetic permeability was <2 in the low-frequency band below 1 GHz.

[0066] Comparative Example 3 The only difference from Example 2 is that the timing of adding stearic acid in step 1 is adjusted from adding in stage 3 to adding stearic acid in stage 2; the remaining steps and parameters are the same as in Example 2.

[0067] The absorber prepared in this comparative example was verified in the same effect as in Example 2, and the results showed that the particle size became relatively smaller, and D50 changed to below 4 um, so that the real part of the magnetic permeability in the low frequency band below 1 GHz obtained by the test became smaller, and the performance in the high frequency band was improved.

[0068] Comparative Example 4 The only difference from Example 2 is that the three-stage ball milling in step 2 is adjusted to two-stage ball milling, specifically: stage 1: ball-to-material ratio of 10:1, rotation speed of 350 rpm, time 2 h; stage 2: adding stearic acid accounting for 1% of the total mass of carbonyl iron powder and carbon nanotubes, ball-to-material ratio of 25:1, rotation speed of 650 rpm, time 4.5 h.

[0069] The absorbent prepared in this comparative example was verified in the same manner as in Example 2. The results showed that the real part of the magnetic permeability of the annular test piece measured by a vector network analyzer and a coaxial air transmission line in the low frequency band below 1 GHz was <6.5, and the imaginary part was <1.8.

[0070] Comparative Example 5 The only difference from Example 2 is that no protective gas (argon) is added during the ball milling process of stages 1 to 3, and the remaining steps and parameters are the same as those of Example 2.

[0071] The same effect verification as in Example 2 was carried out on the absorber prepared in this comparative example. The results showed that the absorber particle surface was severely oxidized, the real part of the magnetic permeability was less than 5, the imaginary part was less than 1.5, and the absorbing frequency band was significantly narrowed.

[0072] Comparative Example 6 The only difference from Example 2 is that nitrogen protection (flow rate 1.0 L / min) is used instead of argon protection during stage 3 ball milling, and the other parameters are the same as those in Example 2.

[0073] The absorber prepared in this comparative example was subjected to the same effect verification as in Example 2. The results showed that the real part of the absorber's magnetic permeability was greater than 6.8, and the imaginary part was greater than 1.9, but the uniformity of the flaky structure was slightly lower than that in Example 2 (the flaky particles accounted for about 85%).

[0074] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing a wave absorbing agent suitable for 5G base station shielding materials, characterized in that: The following steps are involved: The carbonyl iron powder is mixed with the dielectric material and subjected to three-stage ball milling, followed by annealing to obtain the absorbent; The three-stage ball milling is specifically as follows: Stage 1: ball-to-material ratio is 10:1, rotation speed is 300-350 rpm, and time is 2 h; Stage 2: ball-to-material ratio is (20-25):1, speed is 600-700 rpm, and time is 3.5-5 h; Stage 3: After adding additives accounting for 1% of the total mass of carbonyl iron powder and dielectric material, stage 3 ball milling was carried out, with a ball-to-material ratio of 5:1, a rotation speed of 200-250 rpm, and a time of 1 h.

2. The method for preparing the wave absorbing agent suitable for 5G base station shielding material according to claim 1, characterized in that: The mass ratio of the carbonyl iron powder to the dielectric material is (3-10):1; the dielectric material is carbon nanotubes.

3. The method for preparing the wave absorbing agent suitable for 5G base station shielding material according to claim 1, characterized in that: The additive is stearic acid and / or a silane coupling agent.

4. The method for preparing the wave absorbing agent suitable for 5G base station shielding material according to claim 1, characterized in that: The annealing treatment adopts overall annealing or segmented annealing; the overall annealing is specifically: annealing at 200-400°C for 1-3 hours under a protective atmosphere; the segmented annealing is specifically: under a protective atmosphere, first keeping the temperature at 200°C for 1 hour, then heating to 300°C in 1 hour and keeping the temperature for 2 hours, and then heating to 400°C in 1 hour and keeping the temperature for 1 hour.

5. The wave absorbing agent prepared according to the preparation method according to any one of claims 1 to 4.

6. Use of the absorber as claimed in claim 5 in the preparation of 5G base station shielding materials.

7. A 5G base station shielding material, characterized in that: The raw materials include the wave absorbing agent described in claim 5.

8. A method for preparing the 5G base station shielding material according to claim 7, characterized in that: After the absorber is mixed with the rubber, the 5G base station shielding material is obtained by sequentially performing internal mixing, open mixing, sheeting and vulcanization.

9. The method for preparing a 5G base station shielding material according to claim 8, characterized in that: The mass ratio of the absorber to the rubber is 73:27.

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