A wave-absorbing material with anti-static surge performance and its application

Abstract

The present invention provides an absorbing material with anti-static surge performance and its application. According to the weight percentage, the raw materials for preparing the absorbing material include 85-90% FeSiAl magnetic powder and 8-13% resin; wherein the D of the FeSiAl magnetic powder is 50 The particle size is 50~70μm, and the apparent density (AD) is 0.38~0.45g / cm 3 The preparation of the absorbing material includes the following steps: S1. Mixing raw materials to obtain a slurry; S2. Applying the slurry to a film surface and simultaneously performing an orientation treatment to form a coating; then drying the coating to a coating with a solvent content of 15-25% and a thickness of 60-100 μm; S3. Performing a high-temperature hot pressing process on the coating, wherein the reaction temperature during the hot pressing process is not less than 160°C and the reaction pressure is not less than 160 kg. This absorbing material can reduce the damage caused by electrostatic surges to electronic devices.

Description

Technical Field

[0001] The present invention belongs to the field of wave-absorbing materials, and in particular relates to a wave-absorbing material with anti-static surge performance and application thereof. Background Art

[0002] The unexpected generation of excessive voltage or current due to electrostatic discharge is called an electrostatic surge. Typically, electrostatic discharge (ESD) can cause severe damage to electronic components in an instant because it involves the rapid discharge of high voltage, which can cause circuit damage or permanent failure. Therefore, in some cases, an electrostatic surge can cause more immediate and severe damage, especially to sensitive equipment that is not properly protected.

[0003] Current technologies protect electronic devices from electrostatic surges by introducing ESD diodes and TVS diodes to quickly conduct static electricity and limit voltage peaks, or by using components such as gas discharge tubes and varistors to absorb or conduct the energy released by transient electrostatic surges. However, while electromagnetic shielding technology can theoretically block the propagation of electromagnetic waves, it rarely mitigates the damage caused by electrostatic surges to electronic devices or their components. This is because electromagnetic shielding technology is primarily used to address electromagnetic interference, which is typically persistent signal interference that may affect the normal operation of electronic equipment but does not necessarily cause immediate damage to the equipment or its components.

[0004] The principles of electromagnetic shielding can be understood using transmission line theory. This approach considers the shield as a segment of a transmission line. When an electromagnetic wave radiation field approaches the shield, a portion is reflected from its surface, while the remainder is transmitted through the shield and continues to propagate. Within the shield, the electromagnetic wave is attenuated and undergoes multiple reflections and transmissions at two interfaces. Therefore, the shielding mechanism for electromagnetic waves propagating to the shield surface includes reflection dissipation at the incident surface, absorption by the shield material, and dissipation through multiple reflections and transmissions within the shield. Summary of the Invention

[0005] In order to improve the damage of electrostatic surge to electronic equipment, the present invention provides an absorbing material with anti-static surge performance and application thereof.

[0006] According to one aspect of the present invention, there is provided an absorbing material with anti-static surge performance. The raw materials for preparing the absorbing material include 85-90% FeSiAl magnetic powder and 8-13% resin, calculated by mass percentage. 50 The particle size is 50~70μm, and the apparent density (AD) is 0.38~0.45g / cm 3; The preparation of the absorbing material includes the following steps: S1. mixing the raw materials to obtain a slurry; S2. coating the slurry on the surface of the film, and at the same time performing an orientation treatment to form a coating film from the slurry; then drying the coating film to a coating with a solvent content of 15-25% and a thickness of 60-100 μm through a drying treatment; S3. performing a high-temperature hot pressing treatment on the coating, wherein the reaction temperature of the high-temperature hot pressing treatment is not lower than 160°C, and the reaction pressure is not lower than 160 kg.

[0007] The present invention, through a special process and formula, can prepare an absorbing material with anti-static surge performance. Specifically, the present invention can ensure that the absorbing material has a smooth magnetic circuit at the moment of static discharge by introducing a relatively high content of FeSiAl magnetic powder. Furthermore, by performing an orientation treatment with auxiliary FeSiAl magnetic powder during the coating process, it can ensure that the magnetic powders are connected to each other, which not only improves the magnetic permeability of the absorbing material, but also enables the absorbing material to have a smooth magnetic circuit when encountering the moment of static discharge, so that static electricity is released smoothly without affecting electronic components. In addition, the present invention can provide good reaction conditions for the preparation of absorbing materials by controlling the solvent content of the coating and the reaction temperature and pressure of the high-temperature hot pressing treatment, so that the surface of the absorbing material is smooth, free of bubbles and particles, thereby ensuring that the absorbing material can improve the damage caused by static surges to electronic equipment or its components.

[0008] Preferably, the resin includes a polyurethane resin, and the polyurethane resin includes at least one of a polyether polyurethane resin, a polyester polyurethane resin, a polyimide polyurethane resin, and a polyurea polyurethane resin.

[0009] Preferably, the resin also includes an acrylic resin, with the mass ratio of acrylic resin to polyurethane resin being 1-1.5:8.5-9. The inventors have discovered that by incorporating appropriate amounts of acrylic resin and polyurethane resin into the preparation of an absorbing material, the absorbing material can be endowed with excellent mechanical properties and chemical resistance, making it suitable for continuous industrial production (e.g., applications in electromagnetic shielding devices, electrostatic discharge protection devices, and electrostatic surge protection devices).

[0010] Preferably, in S1, the viscosity of the slurry is adjusted to 20,000-35,000 mPa / s. The viscosity of the slurry can be adjusted by introducing a solvent.

[0011] Preferably, the solvent includes at least one of ethyl acetate, sec-butyl acetate, cyclohexanone, N-dimethylformamide, N-dimethylacetamide, butanone, ethyl acetate, butyl acetate, toluene, and xylene.

[0012] Preferably, in S2, the drying process includes a first drying stage, a second drying stage, a third drying stage, a fourth drying stage, and a fifth drying stage; wherein the drying temperature of the first drying stage is 75-85°C, the drying temperature of the second drying stage is 95-105°C, the drying temperature of the third and fourth drying stages is 110-125°C, and the drying temperature of the fifth drying stage is 125-135°C. By controlling a reasonable temperature range, it is possible to ensure that the solvent content in the coating remains within a reasonable range and to avoid problems such as the product surface being rough and cracked due to boiling of the solvent, thereby affecting the anti-static surge performance of the absorbing material.

[0013] Preferably, the drying time for the first, second, third, fourth, and fifth drying stages is 2-3 minutes, respectively. If the drying time is too short, the coating will have a high residual solvent rate and high humidity. During high-temperature hot pressing, a large number of bubbles will form on the product surface (due to excessive solvent residue and the inability to expel gases in time under high temperature and pressure). This will also affect the normal winding of the product (the product layers will stick together). If the drying time is too long, the product will have a slight burnt odor. If a vulcanizing agent is added to the slurry, the coating will easily become semi-vulcanized before the high temperature and high pressure stage, which will reduce the performance of the subsequent product.

[0014] Preferably, in S3, the reaction temperature of the high-temperature hot pressing treatment is 160-200° C.; and / or the reaction pressure is 160-200 kg.

[0015] Preferably, in S3, at least two coating layers are stacked and completely overlapped before being subjected to high-temperature hot pressing.

[0016] Preferably, the raw materials for preparing the absorbing material further include a vulcanizing agent, and the amount of the vulcanizing agent added is 5-8% of the mass of the resin.

[0017] Preferably, the vulcanizing agent includes at least one of sulfur, 4,4'-methylenebis(2-chloroaniline) (MOCA), dicumyl peroxide (DCP), di-tert-butyl peroxide (DTBP), and di-tert-butylperoxyisopropylbenzene (BIPB).

[0018] Preferably, the raw materials for preparing the absorbing material further include a coupling agent, and the added amount of the coupling agent is 1-5% of the mass of the FeSiAl magnetic powder.

[0019] Preferably, the coupling agent includes a silane coupling agent, a titanate coupling agent, such as at least one of KH550, KH560, and vinyltriethoxysilane.

[0020] Preferably, the raw materials for preparing the absorbing material further include an auxiliary agent, and the auxiliary agent includes at least one of a wetting agent and a defoaming agent.

[0021] Preferably, the amount of the wetting agent added is 0.3-0.9% of the mass of the FeSiAl magnetic powder.

[0022] Preferably, the amount of the defoaming agent added is 0.3-0.9% of the mass of the FeSiAl magnetic powder.

[0023] Preferably, the film comprises a PET film.

[0024] Another aspect of the present invention provides an application of the above-mentioned absorbing material in the field of electromagnetic shielding. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a test chart of the magnetic permeability of the absorbing material provided by treatment group 1A of Example 1 of the present invention;

[0026] Figure 2 This is a coating image provided by treatment group 1A of Example 1 of the present invention;

[0027] Figure 3 This is a picture of the absorbing material product provided by treatment group 8A of Example 1 of the present invention;

[0028] Figure 4 This is a picture of the absorbing material product provided by treatment group 11A of Example 1 of the present invention;

[0029] Figure 5 This is a comparison between the image of the absorbing material product provided by treatment group 1A of Example 1 of the present invention and other samples that experienced powder loss. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention and the drawings in the embodiments. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0031] Example 1

[0032] Treatment group 1A

[0033] 1. Raw materials required for preparing absorbing materials

[0034] The absorbing material of this treatment group was prepared according to the formula provided in Table 1.

[0035] Table 1. Raw materials required for preparing absorbing materials in treatment group 1A

[0036]

[0037] 2. Method for preparing absorbing materials

[0038] S1. The raw materials shown in Table 1 are mixed to obtain a slurry;

[0039] S2. The slurry is applied to the surface of a PET film and simultaneously oriented to form a coating film. The coating film is then dried through a first drying stage, a second drying stage, a third drying stage, a fourth drying stage, and a fifth drying stage until the coating has a solvent content of 20% and a thickness of 80 μm.

[0040] Among them, the drying temperature of the first drying stage is 80°C, and the drying time is 2.5 minutes; the drying temperature of the second drying stage is 100°C, and the drying time is 3 minutes; the drying temperature of the third drying stage is 110°C, and the drying time is 2 minutes; the drying temperature of the fourth drying stage is 120°C, and the drying time is 3 minutes; the drying temperature of the fifth drying stage is 130°C, and the drying time is 3 minutes.

[0041] S3. Take 13 sheets of the above coating, completely overlap and stack them, and then perform high-temperature hot pressing to obtain an absorbing material with a thickness of 0.3 mm; wherein the reaction temperature of the high-temperature hot pressing treatment is 190°C and the reaction pressure is 180 kg.

[0042] Treatment group 2A

[0043] This treatment group prepared absorbing materials using the same formula and method as that of Treatment Group 1A in Example 1. However, this treatment group differed from Treatment Group 1A in that the coating thickness was 60 μm. In S3, 18 sheets of the coating were subjected to high-temperature hot pressing to obtain absorbing materials with a thickness of 0.3 mm. Aside from these differences, the procedures for preparing the absorbing materials in this treatment group were identical to those in Treatment Group 1A in Example 1.

[0044] Treatment group 3A

[0045] This treatment group prepared the absorbing material using the formula and method provided in Treatment Group 1A of Example 1. Unlike Treatment Group 1A of Example 1, this treatment group used a coating with a thickness of 100 μm. In S3, 18 coatings were subjected to high-temperature hot pressing to obtain an absorbing material with a thickness of 0.3 mm. Aside from these differences, the procedures for preparing the absorbing material in this treatment group were strictly consistent with those in Treatment Group 1A of Example 1.

[0046] Treatment group 4A

[0047] This treatment group prepared the absorbing material using the formula and method provided in Treatment Group 1A of Example 1. Unlike Treatment Group 1A of Example 1, this treatment group used a 25% solvent content in the coating layer. Other than these differences, the procedures for preparing the absorbing material in this treatment group were strictly consistent with those in Treatment Group 1A of Example 1.

[0048] Treatment group 5A

[0049] This treatment group prepared the absorbing material using the formula and method provided in Treatment Group 1A of Example 1. Unlike Treatment Group 1A of Example 1, this treatment group used a 15% solvent content in the coating layer. Other than these differences, the procedures for preparing the absorbing material in this treatment group were strictly consistent with those in Treatment Group 1A of Example 1.

[0050] Treatment group 6A

[0051] This treatment group prepared the absorbing material using the formula and method provided in Treatment Group 1A of Example 1. Unlike Treatment Group 1A of Example 1, this treatment group used a high-temperature autoclave reaction temperature of 160°C. Apart from these differences, the process steps for preparing the absorbing material in this treatment group were strictly consistent with those in Treatment Group 1A of Example 1.

[0052] Treatment group 7A

[0053] This treatment group prepared the absorbing material using the formula and method provided in Treatment Group 1A of Example 1. Unlike Treatment Group 1A of Example 1, this treatment group used a high-temperature autoclave reaction temperature of 200°C. Apart from these differences, the operational steps for preparing the absorbing material in this treatment group were strictly consistent with those in Treatment Group 1A of Example 1.

[0054] Treatment Group 8A

[0055] This treatment group prepared the absorbing material using the formula and method provided in Treatment Group 1A of Example 1. Unlike Treatment Group 1A of Example 1, this treatment group used a high-temperature autoclave reaction temperature of 210°C. Apart from these differences, the operational procedures for preparing the absorbing material in this treatment group were strictly consistent with those in Treatment Group 1A of Example 1.

[0056] Treatment Group 9A

[0057] This treatment group prepared the absorbing material using the formula and method provided in Treatment Group 1A of Example 1. Unlike Treatment Group 1A of Example 1, this treatment group used a high-temperature autoclave pressure of 160 kg. Aside from these differences, the process steps for preparing the absorbing material in this treatment group were strictly consistent with those in Treatment Group 1A of Example 1.

[0058] Treatment Group 10A

[0059] This treatment group prepared the absorbing material using the formula and method provided in Treatment Group 1A of Example 1. Unlike Treatment Group 1A of Example 1, this treatment group used a high-temperature autoclave pressure of 200 kg. Apart from these differences, the process steps for preparing the absorbing material in this treatment group were strictly consistent with those in Treatment Group 1A of Example 1.

[0060] Treatment Group 11A

[0061] This treatment group prepared the absorbing material using the formula and method provided in Treatment Group 1A of Example 1. Unlike Treatment Group 1A of Example 1, this treatment group used a high-temperature autoclave pressure of 250 kg. Aside from these differences, the process steps for preparing the absorbing material in this treatment group were strictly consistent with those in Treatment Group 1A of Example 1.

[0062] Comparative group 1A

[0063] This comparative group prepared absorbing material using the formula and method described in Treatment Group 1A of Example 1. Unlike Treatment Group 1A of Example 1, this comparative group used a coating with a thickness of 40 μm. In S3, 26 sheets of the coating were subjected to high-temperature hot pressing to obtain an absorbing material with a thickness of 0.3 mm. Aside from these differences, the procedures for preparing the absorbing material in this comparative group were strictly consistent with those in Treatment Group 1A of Example 1.

[0064] Comparative group 2A

[0065] This comparative group prepared absorbing material using the formula and method described in Treatment Group 1A of Example 1. Unlike Treatment Group 1A of Example 1, this comparative group used a coating with a thickness of 150 μm. Seven sheets of the coating were subjected to high-temperature hot pressing in S3 to obtain an absorbing material with a thickness of 0.3 mm. Aside from these differences, the procedures for preparing the absorbing material in this comparative group were identical to those in Treatment Group 1A of Example 1.

[0066] Comparative group 3A

[0067] This comparative group prepared the absorbing material using the formula and method provided in Treatment Group 1A of Example 1. Unlike Treatment Group 1A of Example 1, the solvent content of the coating layer in this comparative group was 30%. Other than these differences, the preparation procedures for the absorbing material in this comparative group were strictly consistent with those in Treatment Group 1A of Example 1.

[0068] Control group 4A

[0069] This comparative group prepared the absorbing material using the formula and method provided in Treatment Group 1A of Example 1. Unlike Treatment Group 1A of Example 1, the solvent content of the coating layer in this comparative group was 10%. Other than these differences, the preparation procedures for the absorbing material in this comparative group were strictly consistent with those in Treatment Group 1A of Example 1.

[0070] Control group 5A

[0071] This comparative group prepared the absorbing material using the formula and method provided in Treatment Group 1A of Example 1. Unlike Treatment Group 1A of Example 1, the reaction temperature for the high-temperature autoclaving process in this comparative group was 140°C. Aside from these differences, the operational procedures for preparing the absorbing material in this comparative group were strictly consistent with those in Treatment Group 1A of Example 1.

[0072] Control group 6A

[0073] This comparative group prepared absorbing materials using the formula and method provided in Treatment Group 1A of Example 1. Unlike Treatment Group 1A of Example 1, this comparative group used a high-temperature autoclave pressure of 100 kg. Aside from these differences, the procedures for preparing the absorbing materials in this comparative group were strictly consistent with those in Treatment Group 1A of Example 1.

[0074] Control group 7A

[0075] This comparative group prepared the absorbing material using the formula and method provided in Treatment Group 1A of Example 1. Unlike Treatment Group 1A of Example 1, this comparative group did not perform an orientation treatment in S2 during the preparation of the absorbing material. Aside from these differences, the operational steps for preparing the absorbing material in this comparative group were strictly consistent with those in Treatment Group 1A of Example 1.

[0076] Test Example 1

[0077] 1. Test subjects

[0078] The absorbing materials prepared in each treatment group and control group in Example 1.

[0079] 2. Test Method

[0080] (1) Magnetic permeability: The test object was cut into a ring with an inner diameter of 9 mm and an outer diameter of 16 mm on a mold and tested on an E4991B precision impedance analyzer.

[0081] (2) Density: tested using the Archimedes drainage method.

[0082] (3) Electrostatic test: Use an electrostatic gun (brand Noiseken, model: GT-30RA, host model: ESS-S3011A) to discharge vertically at the VGA port, 180 shots each time, for a total of 7 times. If the test object has the ability to resist electrostatic surges, the motherboard will work normally; otherwise, it will freeze. "O" indicates that the test object has passed the electrostatic test (it has anti-static surge performance); "X" indicates that the electrostatic test has failed (it does not have anti-static surge performance).

[0083] (4) Powder loss: First, take a 3M-610 tape longer than 150mm. The adhesive surface of the tape should not come into contact with hands or other materials. Stick the tape surface to the surface of the test object, leaving a 20mm tearing space. Then use a manual rolling roller (2KG) to roll back and forth on the test material 3 times at a nearly uniform speed under its own weight (no bubbles are allowed on the surface of the test object), so that the tape surface is fully fitted with the test surface, and let it stand for 10 seconds. Then, stand up one end of the tearing portion of the tape, make it 90 degrees to the test surface, and tear off the tape at a nearly uniform speed. Observe whether there is powder stuck in the tape, and use "O" to indicate that the test object does not shed powder; "X" indicates that the test object sheds powder.

[0084] (5) Appearance: Observe the surface condition of the test object visually, with the naked eye at a distance of 30 cm to 45 cm from the object. “O” indicates that the test object is smooth, particle-free, and bubble-free; “X” indicates that the test object is not smooth, has particles, or has bubbles.

[0085] (6) Solvent content in the coating: measured by Ohaus moisture analyzer.

[0086] 3. Test results and analysis

[0087] The test results of this test example are shown in Table 2. The magnetic permeability of the absorbing material obtained by the treatment group 1A of Example 1 is as follows: Figure 1 As shown (μ' represents magnetic permeability, μ' represents the real part of relative magnetic permeability; μ" represents the imaginary part of relative magnetic permeability; μ' characterizes the response degree of the material to the magnetic flux under the action of the magnetic field, and represents the magnetization intensity of the material in the magnetic field; μ" characterizes the material's ability to absorb or radiate the magnetic field, and represents the loss characteristics of the material). The coating is as shown Figure 2 shown.

[0088] The test results for treatment groups 1A-3A and comparison groups 1A-2A show that coating thickness not only affects the absorber's anti-static surge performance but also hinders normal production. Specifically, when the coating thickness is too thin, stringing can occur between the two scrapers during the coating process, hindering normal production. For comparison group 1A, molding was impossible, and therefore no corresponding data could be measured.

[0089] As shown in treatment group 1A, treatment groups 4A-5A, and control groups 3A-4A, the solvent content in the coating also affects the absorbing material's anti-static surge performance, magnetic permeability, and appearance. Specifically, when the solvent content in the coating is too high, the gas cannot be promptly expelled during high-temperature hot pressing, resulting in dense bubbles on the surface of the absorbing material, significantly reducing the absorbing material's anti-static surge performance. When the solvent content in the coating is too low, the resin components in the coating undergo a preliminary cross-linking reaction, preventing the resin from fully vulcanizing during the subsequent high-temperature hot pressing process, resulting in a soft and rough surface.

[0090] It can be seen from the treatment group 1A, treatment groups 6A~8A and comparison group 5A that when the reaction temperature in the high temperature hot pressing treatment is too low, the anti-static surge performance of the absorbing material will be affected; when the reaction temperature is too high, bubbles will appear, such as Figure 3 shown.

[0091] From the treatment group 1A, treatment groups 9A~11A and comparison group 6A, it can be seen that when the reaction pressure in the high temperature hot pressing treatment is too low, the anti-static surge performance of the absorbing material will be affected; when the reaction pressure is too high, cracks and bubbles will appear on the surface of the absorbing material. Figure 4 As shown. Figure 5 It can be seen that there are no powder loss, slight powder loss and severe powder loss in the absorbing material.

[0092] However, it can be seen from the treatment group 1A and the comparison group 7A that when the orientation treatment is not performed in S2, the absorbing material cannot be guaranteed to have a smooth magnetic circuit, thereby significantly reducing the anti-static surge performance of the absorbing material.

[0093] Furthermore, the present invention utilizes a multi-stage drying process, remedying the technical issues encountered by existing single-stage drying methods. For example, if the drying temperature is too low, the coating can contain excessively high levels of residual solvent, which can cause boiling during high-temperature hot pressing, resulting in a rough product surface. If the drying temperature is too high, the solvent in the slurry can boil during the drying process, resulting in a rough surface and a ruptured bubble pattern on the absorber, which can affect the absorber's performance.

[0094] Table 2. Test results of this test case

[0095]

[0096] Example 2

[0097] Treatment group 1B

[0098] This treatment group prepared the absorbing material strictly according to the formula and method provided in treatment group 1A of Example 1.

[0099] Treatment group 2B

[0100] This treatment group prepared the absorbing material by referring to the formula and method provided by treatment group 1B of Example 2. The difference from treatment group 1B of Example 2 is that the FeSiAl magnetic powder used in this treatment group is D 50 =65 μm. Except for the above differences, the operation steps for preparing the absorbing material in this treatment group are strictly consistent with those of treatment group 1B in Example 2.

[0101] Treatment group 4B

[0102] This treatment group prepared the absorbing material by referring to the formula and method provided by treatment group 1B of Example 2. The difference from treatment group 1B of Example 2 is that the FeSiAl magnetic powder used in this treatment group when preparing the absorbing material has an AD of 0.40 g / cm 3 Except for the above differences, the operation steps for preparing the absorbing material in this treatment group are strictly consistent with those of treatment group 1B in Example 2.

[0103] Treatment group 5B

[0104] This treatment group prepared the absorbing material by referring to the formula and method provided by treatment group 1B of Example 2. The difference from treatment group 1B of Example 2 is that the FeSiAl magnetic powder used in this treatment group when preparing the absorbing material has an AD of 0.45 g / cm 3 Except for the above differences, the operation steps for preparing the absorbing material in this treatment group are strictly consistent with those of treatment group 1B in Example 2.

[0105] Treatment group 6B

[0106] This treatment group prepared the absorbing material using the formula and method described in Treatment Group 1B of Example 2. However, this treatment group differed from Treatment Group 1B in that the resin used in preparing the absorbing material also included acrylic resin (Mitsubishi, brand MB2952). The mass ratio of acrylic resin to polyurethane resin was 1:9 (the total mass fraction of the resins remained unchanged). Aside from these differences, the procedures for preparing the absorbing material in this treatment group were identical to those in Treatment Group 1B of Example 2.

[0107] Treatment group 7B

[0108] This treatment group prepared the absorbing material using the formula and method described in Treatment Group 1B of Example 2. Unlike Treatment Group 1B of Example 2, this treatment group also used acrylic resin (Yoshida, brand 116) in the preparation. The mass ratio of acrylic resin to polyurethane resin was 1.5:8.5 (the total mass fraction of the resins remained unchanged). Aside from these differences, the procedures for preparing the absorbing material in this treatment group were identical to those in Treatment Group 1B of Example 2.

[0109] Treatment group 8B

[0110] This treatment group prepared the absorbing material using the formula and method described in Treatment Group 1B of Example 2. Unlike Treatment Group 1B of Example 2, this treatment group also used acrylic resin (Yoshida brand S-160) in the preparation of the absorbing material. The mass ratio of acrylic resin to polyurethane resin was 4:6 (the total mass fraction of the resins remained unchanged). Aside from these differences, the procedures for preparing the absorbing material in this treatment group were identical to those in Treatment Group 1B of Example 2.

[0111] Control group 1B

[0112] The comparative group prepared the absorbing material by using the formula and method provided by the treatment group 1B of Example 2. The difference from the treatment group 1B of Example 2 is that the magnetic powder used in the preparation of the absorbing material in the comparative group is FeSiCr (D 50 =68μm, AD=0.37g / cm 3 ). Except for the above differences, the operation steps for preparing the absorbing material in this comparative group were strictly consistent with those of the treatment group 1B in Example 2.

[0113] Control group 2B

[0114] The comparative group prepared the absorbing material by using the formula and method provided by the treatment group 1B of Example 2. The difference from the treatment group 1B of Example 2 is that the magnetic powder used in the preparation of the absorbing material in the comparative group is FeSiCr (D 50 =65μm, AD=0.40g / cm 3 ). Except for the above differences, the operation steps for preparing the absorbing material in this comparative group were strictly consistent with those of the treatment group 1B in Example 2.

[0115] Control group 3B

[0116] The comparative group prepared the absorbing material by the formula and method provided by the treatment group 1B of Example 2. The difference from the treatment group 1B of Example 2 is that the FeSiAl magnetic powder used in the comparative group is D 50=58 μm. Except for the above differences, the operation steps for preparing the absorbing material in this comparative group are strictly consistent with those of the treatment group 1B in Example 2.

[0117] Control group 4B

[0118] The comparative group prepared the absorbing material by the formula and method provided by the treatment group 1B of Example 2. The difference from the treatment group 1B of Example 2 is that the FeSiAl magnetic powder used in the comparative group is D 50 =80 μm. Except for the above differences, the operation steps for preparing the absorbing material in this comparative group were strictly consistent with those of treatment group 1B in Example 2.

[0119] Control group 5B

[0120] The comparative group prepared the absorbing material by using the formula and method provided by the treatment group 1B of Example 2. The difference from the treatment group 1B of Example 2 is that the FeSiAl magnetic powder used in the preparation of the absorbing material in this comparative group has an AD of 0.47 g / cm 3 Except for the above differences, the operation steps for preparing the absorbing material in this comparative group were strictly consistent with those of the treatment group 1B in Example 2.

[0121] Control group 6B

[0122] The comparative group prepared the absorbing material by using the formula and method provided by the treatment group 1B of Example 2. The difference from the treatment group 1B of Example 2 is that the FeSiAl magnetic powder used in the preparation of the absorbing material in this comparative group has an AD of 0.33 g / cm 3 Except for the above differences, the operation steps for preparing the absorbing material in this comparative group were strictly consistent with those of the treatment group 1B in Example 2.

[0123] Control group 7B

[0124] This comparative group prepared the absorbing material using the formula and method provided in Treatment Group 1B of Example 2. Unlike Treatment Group 1B of Example 2, this comparative group used 70% FeSiAl magnetic powder by weight (and the resin content in the formula was 8-13% by weight). Other than these differences, the preparation procedures for the absorbing material in this comparative group were strictly consistent with those in Treatment Group 1B of Example 2.

[0125] Control group 8B

[0126] This comparative group prepared the absorbing material using the formula and method provided in Treatment Group 1B of Example 2. Unlike Treatment Group 1B of Example 2, this comparative group used 95% FeSiAl magnetic powder (and the resin content in the formula was 8-13%). Other than these differences, the preparation procedures for the absorbing material in this comparative group were identical to those in Treatment Group 1B of Example 2.

[0127] Test Example 2

[0128] 1. Test subjects

[0129] The absorbing materials prepared in each treatment group and control group in Example 2.

[0130] 2. Test Method

[0131] Perform the test according to the method provided in Test Example 2.

[0132] 3. Test results and analysis

[0133] The test results of this test case are shown in Table 3.

[0134] The test results of treatment group 1B and comparison groups 1B to 2B show that if other types of soft magnetic powder are replaced, the resulting absorbing material will have difficulty passing the electrostatic test.

[0135] The test results of treatment groups 1B~5B and comparison groups 3B~6B show that the D 50 The bulk density will significantly affect the magnetic permeability and anti-static surge performance of the absorbing material. This is because the size of the magnetic powder will affect its vulcanization and cross-linking reaction during high-temperature hot pressing.

[0136] Treatments 1B and 6B-8B demonstrate that inappropriate inclusion of acrylic resin can reduce the mechanical properties, mechanical performance, and application of the absorbent material. The absorbent material produced by treatment 8B becomes sticky when used at high temperatures and brittle at low temperatures, limiting its application. Furthermore, the reduced adhesion leads to delamination and shedding of the coating and film. Combined with the data from treatments 6B-8B, a mass ratio of acrylic resin to polyurethane resin of 1-1.5:8.5-9 allows for a good bond between the polyurethane and acrylic resins, resulting in a polyurethane-acrylic composite emulsion (PUA) that combines the advantages of both polyurethane and acrylic emulsions, such as excellent mechanical properties and chemical resistance, making it suitable for continuous industrial production. However, when this mass ratio is not met (as in treatment 8B), the absorbent material may pass electrostatic testing, but its mechanical properties are too rigid to meet practical application standards.

[0137] From the treatment group 1B and the comparison groups 7B-8B, it can be seen that when the magnetic powder content is too low, a smooth magnetic circuit cannot be guaranteed at the moment of static discharge, resulting in the produced absorbing material failing the static test; and when the magnetic powder content is too high, there are too few colloid particles (which act as a binder) in the material as a whole, making it impossible to shape the magnetic powder in an orderly and uniform manner, which is not conducive to stable mass production.

[0138] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

[0139] Table 3. Test results of this test case

[0140]

Claims

1. A wave-absorbing material with anti-static surge performance, characterized by: Calculated by mass percentage, the raw materials for preparing the absorbing material include 85-90% FeSiAl magnetic powder and 8-13% resin; Wherein, the D of the FeSiAl magnetic powder 50 The particle size is 50~70μm, and the apparent density is 0.38~0.45g / cm 3 ; The resin is polyurethane resin and acrylic resin; calculated by mass ratio, the acrylic resin: the polyurethane resin = 1-1.5:8.5-9; The raw materials for preparing the absorbing material also include a vulcanizing agent, and the amount of the vulcanizing agent added is 5-8% of the mass of the resin; The vulcanizing agent includes at least one of sulfur, dicumyl peroxide, di-tert-butyl peroxide, and di-tert-butyl peroxyisopropylbenzene; The polyurethane resin includes at least one of a polyether polyurethane resin and a polyester polyurethane resin; The preparation of the absorbing material comprises the following steps: S1. mixing the raw materials to obtain a slurry; S2. The slurry is coated on the surface of the film, and at the same time, an orientation treatment is performed to form a coating film of the slurry; the coating film is then dried by a drying process to a solvent content of 15 to 25% and a thickness of 60 to 100 μm; S3. The coating is subjected to high-temperature hot pressing treatment, wherein the reaction temperature of the high-temperature hot pressing treatment is not less than 160°C and the reaction pressure is not less than 160Kg.

2. The absorbing material according to claim 1, wherein: In S1 , the viscosity of the slurry is adjusted to 20,000 to 35,000 mPa·s.

3. The absorbing material according to claim 1, wherein: In S2, the drying process includes first-stage drying, second-stage drying, third-stage drying, fourth-stage drying, and fifth-stage drying; wherein, the drying temperature of the first-stage drying is 75-85°C, the drying temperature of the second-stage drying is 95-105°C, the drying temperature of the third-stage drying and the fourth-stage drying is 110-125°C, and the drying temperature of the fifth-stage drying is 125-135°C.

4. The absorbing material according to claim 1, wherein: In S3, the reaction temperature of the high-temperature hot pressing treatment is 160-200° C.; and / or the reaction pressure is 160-200 kg.

5. The absorbing material according to claim 1, wherein: The raw materials for preparing the absorbing material also include a coupling agent, and the added amount of the coupling agent is 1-5% of the mass of the FeSiAl magnetic powder.

6. Use of the absorbing material according to any one of claims 1 to 5 in an electromagnetic shielding device, an electrostatic discharge protection device, or an electrostatic surge protection device.

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