Preparation and application of electromagnetic wave absorption and transmission integrated material

Abstract

The invention relates to the technical field of composite materials, and provides preparation and application of an electromagnetic wave absorption and transmission integrated material. The electromagnetic wave absorbing and transmitting integrated material comprises a wave-transmitting substrate layer and a functional layer which are sequentially arranged from top to bottom, the material of the wave-transmitting substrate layer comprises the following components in parts by weight: 50-70 parts of polyolefin and 30-50 parts of a hydroxyl acrylate polymer, and the material of the functional layer comprises the following components in parts by weight: 2-10 parts of carbon nanotubes, 15-45 parts of a rare earth material and 40-70 parts of polymer glue; the pattern of the functional layer is of a periodic array structure. By means of the technical scheme, the problem that in the prior art, a wave-absorbing material cannot achieve high wave-transparent performance and high wave-absorbing performance at the same time is solved.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, specifically to the preparation and application of an integrated electromagnetic wave absorbing and penetrating material. Background Technology

[0002] With the rapid development of modern electronic technology, electromagnetic compatibility and electromagnetic protection issues have become increasingly prominent. In fields such as radar systems, communication equipment, and stealth technology, materials often need to possess both wave-transmitting and wave-absorbing capabilities. For example, in the design of radomes for stealth aircraft, high wave transmission is required to ensure the smooth transmission of friendly communication signals, while high wave absorption is needed to effectively absorb enemy detection radar waves.

[0003] Traditional absorbing materials such as ferrites and conductive rubbers have good absorption properties, but they often lack frequency selectivity, making it difficult to form a "transmission window" in a specific frequency band. While existing frequency selective surface (FSS) technology can achieve a frequency-selective "transmission window," it cannot effectively absorb electromagnetic waves in a specific frequency band, and it also suffers from problems such as complex processing technology, high cost, and difficulty in effectively integrating with absorbing materials.

[0004] Therefore, developing a new material that can simultaneously achieve high wave transmission and high wave absorption performance, and has a designable "wave transmission window" and "wave absorption window", has important practical application value. Summary of the Invention

[0005] This invention proposes a method for preparing and applying an integrated electromagnetic wave absorbing and penetrating material, which solves the problem that absorbing materials in related technologies cannot simultaneously achieve high wave transmission and high wave absorption performance.

[0006] This invention proposes an integrated electromagnetic wave absorbing and penetrating material, comprising a wave-transparent substrate layer and a functional layer arranged sequentially from top to bottom. The material of the wave-transparent substrate layer includes the following components in parts by weight: 50-70 parts of polyolefin and 30-50 parts of hydroxy acrylate polymer; The material of the functional layer includes the following components in parts by weight: 2-10 parts carbon nanotubes, 15-45 parts rare earth materials, and 40-70 parts polymer adhesive. The pattern of the functional layer is a periodic array structure.

[0007] As a further technical solution, the electromagnetic wave absorbing and penetrating integrated material has a wave transmittance of >90% in the target frequency band within the 0~6GHz frequency range, and a wave absorption rate better than -10dB in other frequency bands.

[0008] As a further technical solution, the hydroxy acrylate polymer includes one or more of the following: hydroxyethyl polyacrylate, hydroxyethyl polymethacrylate, hydroxypropyl polyacrylate, hydroxypropyl polymethacrylate, hydroxybutyl polyacrylate, and hydroxybutyl polymethacrylate.

[0009] As a further technical solution, the carbon nanotubes include one or both of single-walled carbon nanotubes and multi-walled carbon nanotubes.

[0010] As a further technical solution, the rare earth material includes one or more of samarium cobalt, neodymium iron boron, or yttrium iron garnet.

[0011] As a further technical solution, the polymer adhesive includes one or more of polyurethane, epoxy resin, and epoxy-modified silicone resin.

[0012] As a further technical solution, the polymer adhesive comprises a mixture of polyurethane and epoxy-modified silicone resin in a mass ratio of 1:2~3.

[0013] This invention also proposes a method for preparing the aforementioned electromagnetic wave-absorbing integrated material, comprising the following steps: S1. Polyolefin and hydroxy acrylate polymer are mixed and extruded into a film to obtain a wave-transparent substrate layer; Carbon nanotubes, rare earth materials and polymer adhesives are mixed and then added to a solvent. Dispersant and curing agent are added and mixed evenly to obtain a composite slurry. S2. The mixed slurry is coated on the wave-transparent substrate layer and cured to form a functional layer, thus obtaining an integrated electromagnetic wave absorbing and penetrating material.

[0014] As a further technical solution, in step S2, the coating is performed according to a pattern of a periodic array structure.

[0015] The present invention also proposes applications of the electromagnetic wave penetrating integrated material, including applications in stealth radomes, electromagnetic compatibility devices, or communication devices.

[0016] The working principle and beneficial effects of this invention are as follows: In this invention, the electromagnetic wave absorbing and penetrating integrated material includes both a wave-transmitting substrate layer and a functional layer, enabling the material to exhibit high wave transmission characteristics within a specific frequency band and high wave absorption characteristics in other specific frequency bands. Unlike traditional wave-absorbing materials, the technical solution of this invention has the following advantages: (1) The wave-transparent substrate material is made of polyolefin and hydroxy acrylate polymer. Polyolefin material has low dielectric constant and low dielectric loss, which can reduce the reflection of electromagnetic waves at the material interface and reduce the energy loss when electromagnetic waves penetrate the material. Hydroxy acrylate polymer optimizes the molecular structure. The two are used together to make the material transmittance >90% in the target frequency band of 0~6GHz, ensuring efficient penetration of electromagnetic waves in a specific frequency band. The combination of polyolefin and hydroxy acrylate polymer ensures the long-term stability of the wave-transparent substrate performance. (2) Carbon nanotubes, rare earth materials and polymer adhesives are added to the functional layer material. Carbon nanotubes have high strength and impact resistance, making the functional layer thinner and more durable. Rare earth materials have unique electromagnetic property regulation, and polymer adhesives have excellent high temperature resistance. The composite slurry prepared by mixing these three materials forms a functional layer with a periodic array structure through a patterning process. It has high transmittance to the working frequency band and high absorption to other specific frequency bands. At the same time, the functional layer is thin, heat resistant and durable. (3) Polyolefin materials and hydroxy acrylate polymers are selected in the wave-transparent substrate material, so that the electromagnetic wave absorption and penetration integrated material has good flexibility and processability. The electromagnetic wave absorption and penetration integrated material composed of wave-transparent substrate layer and functional layer has a simple preparation process, low cost, and is suitable for large-scale production. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] It should be understood that, unless the context clearly indicates otherwise, the terms “comprising,” “including,” or “having” as used herein refer to the presence of an element, but do not exclude the presence or addition of one or more other elements. Furthermore, as used herein, “comprising” and / or “including” indicate the presence of shapes, numbers, steps, operations, members, elements, and / or combinations thereof, and do not exclude the presence or addition of one or more other shapes, numbers, operations, elements, and / or combinations thereof.

[0019] In this application, the numerical range indicated by "~" refers to the range of values ​​specified as the lower and upper limits, respectively, before or after the term. When multiple values ​​for the upper or lower limit of any numerical range are mentioned, the range disclosed herein can be understood as a range with any one of the mentioned upper limits as its upper limit and any one of the mentioned lower limits as its lower limit.

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the preparation and application of an integrated electromagnetic wave absorbing and penetrating material according to an embodiment of this invention will be described in detail below.

[0021] According to one aspect of the present invention, an electromagnetic wave absorbing and penetrating integrated material is provided, comprising a wave-transparent substrate layer and a functional layer arranged sequentially from top to bottom. The material of the wave-transparent substrate layer includes the following components in parts by weight: 50-70 parts of polyolefin and 30-50 parts of hydroxy acrylate polymer; In this invention, polyolefins and hydroxy acrylate polymers are selected. The polyolefins can be, for example, polyethylene or polypropylene, which have good dielectric properties and reduce electromagnetic wave scattering and absorption. The hydroxy acrylate polymers include one or more of polyhydroxyethyl acrylate, polyhydroxyethyl methacrylate, polyhydroxypropyl acrylate, polyhydroxypropyl methacrylate, polyhydroxybutyl acrylate, and polyhydroxybutyl methacrylate. The introduction of hydroxy acrylate polymers improves the processing fluidity of polyolefins, makes the wave-transparent substrate layer more uniform, and is more conducive to wave transmission.

[0022] The functional layer consists of the following components by weight: 2-10 parts carbon nanotubes, 15-45 parts rare earth materials, and 40-70 parts polymer adhesive; the pattern of the functional layer is a periodic array structure.

[0023] In this invention, carbon nanotubes, rare earth materials, and polymer adhesives are added to the functional layer. The carbon nanotubes include one or two types of single-walled carbon nanotubes and multi-walled carbon nanotubes, preferably multi-walled carbon nanotubes. Multi-walled carbon nanotubes provide a larger specific surface area and higher strength. After being added to the functional layer, not only are the mechanical properties of the functional layer enhanced, but also the wave absorption and wave transmission effects of the functional layer are enhanced.

[0024] Rare earth materials include one or more of samarium cobalt, neodymium iron boron, or yttrium iron garnet. Among rare earth materials, samarium cobalt has high magnetocrystalline anisotropy and saturation magnetization, neodymium iron boron has high magnetic energy crystal, and yttrium iron garnet has low magnetic loss and high gyromagnetic ratio. Using samarium cobalt, neodymium iron boron, or yttrium iron garnet as rare earth materials can ensure the long-term stable operation of the functional layer and even the entire absorber-permeable integrated material, maintaining high transmittance in the 0~6GHz target frequency band and good absorption in other frequency bands.

[0025] The polymer adhesive includes one or more of polyurethane, epoxy resin, and epoxy-modified silicone resin. On the one hand, polyurethane, epoxy resin, and epoxy-modified silicone resin, as polymer adhesives, have excellent bonding ability and high temperature resistance, ensuring the stability of the internal structure of the functional layer. On the other hand, polyurethane, epoxy resin, and epoxy-modified silicone resin can all form hydrogen bonds with hydroxyl acrylate polymers, thereby enabling the wave-transparent substrate layer and the functional layer to be tightly bonded through intermolecular forces. This improves the peel strength of the electromagnetic wave penetrating integrated material and avoids the delamination phenomenon that occurs during the use of the electromagnetic wave penetrating integrated material, which would lead to a decrease in wave absorption and transmission functions.

[0026] In one embodiment of the present invention, the electromagnetic wave transmission-absorbing integrated material has a transmittance of >90% in the target frequency band within the 0~6GHz frequency range, and an absorption rate better than -10dB in other frequency bands.

[0027] The target frequency band is any frequency band within the 0-6 GHz range, such as any one of the following: 0.5 GHz, 1 GHz, 1.5 GHz, 2 GHz, 2.5 GHz, 3 GHz, 3.5 GHz, 4 GHz, 4.5 GHz, 5 GHz, 5.5 GHz, and 6 GHz. Other frequency bands are any frequency bands other than the 0-6 GHz range, such as any one of the following: 12-18 GHz, 8-12 GHz, 8-18 GHz, 8-13.5 GHz, and 5-10 GHz.

[0028] In one embodiment of the present invention, the polymer adhesive comprises a mixture of polyurethane and epoxy-modified silicone resin in a mass ratio of 1:2 to 3.

[0029] In this invention, the mass ratio of polyurethane to epoxy-modified silicone resin is 1:2 to 3, for example, it can be 1:2, 1:2.5, 1:3, etc. Using a specific mass ratio of polyurethane and epoxy-modified silicone resin as a polymer adhesive further improves the peel strength of the integrated electromagnetic wave absorbing material, making the performance of the integrated electromagnetic wave absorbing material more stable.

[0030] According to another aspect of the present invention, the present invention also provides a method for preparing an integrated electromagnetic wave absorbing material, comprising the following steps: S1. Polyolefin and hydroxy acrylate polymer are mixed and extruded into a film to obtain a wave-transparent substrate layer; Carbon nanotubes, rare earth materials and polymer adhesives are mixed and then added to a solvent. Dispersant and curing agent are added and mixed evenly to obtain a composite slurry. S2. The mixed slurry is coated onto the wave-transparent substrate layer and cured to form a functional layer, thus obtaining an integrated electromagnetic wave absorbing and penetrating material.

[0031] In the composite slurry, the solvent is selected to have high solubility in the polymer adhesive, such as one or more of N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide. The mass of the solvent is based on the solid content of the composite slurry, which is 40% to 60%, for example, 40%, 45%, 50%, 55%, and 60%.

[0032] In the composite slurry, the dispersant is selected from substances that can promote the dispersion of carbon nanotubes, rare earth materials, etc. in the solvent. For example, it can be a silane coupling agent, preferably an aminosilane coupling agent KH550. The mass of the dispersant is 2% to 5% of the sum of the mass of carbon nanotubes, rare earth materials and polymer glue, for example, 2%, 3%, 4% and 5%.

[0033] In composite slurries, the curing agent is selected as a closed-type curing agent that is deactivated at room temperature but deactivated at high temperature, which can promote the curing of the polymer adhesive under high temperature conditions. The mass of the curing agent is 20%-30% of the mass of the polymer adhesive.

[0034] In one embodiment of the present invention, in step S2, the coating is performed according to a preset pattern, which is a periodic array structure.

[0035] In this invention, the pattern of the functional layer is a periodic array structure, and the geometry and size of its unit structure are designed according to the target transmission frequency band. Specifically, its structural unit can be cross-shaped, square, circular or polygonal, etc.

[0036] In this invention, a composite paste is coated onto a wave-transparent substrate layer according to a preset pattern using screen printing, inkjet printing, or photolithography. A stepped temperature curing process is then employed to fully cross-link the polymer adhesive, curing it to form a functional layer and obtaining an integrated electromagnetic wave absorbing and permeating material. Stepped temperature curing is a commonly used curing method in this field; for example, it can be cured at 80℃, 120℃, and 180℃.

[0037] In one embodiment of the present invention, the thickness of the wave-transparent substrate layer is 0.05~0.2mm, for example, it can be 0.05mm, 0.1mm, 0.15mm, or 0.2mm; the thickness of the functional layer is 0.05~0.2mm, for example, it can be 0.05mm, 0.1mm, 0.15mm, or 0.2mm.

[0038] According to another aspect of the invention, the invention also proposes the application of electromagnetic wave penetrating integrated materials, including applications in stealth radomes, electromagnetic compatibility devices, or communication devices.

[0039] In the following embodiments, all raw materials are commercially available, and the specifications of each raw material are as follows: Polyethylene: weight average molecular weight is 100,000; Polypropylene: weight average molecular weight is 100,000; Poly(hydroxyethyl methacrylate): Poly(2-hydroxyethyl methacrylate) with a weight-average molecular weight of 300,000; Polyurethane: Model number TPU 5712; Epoxy resin: E-44; Epoxy-modified silicone resin: viscosity 40~80 seconds (Ford cup 4), solid content (25℃, 2h) 50%, epoxy value 0.06~0.16; Multi-walled carbon nanotubes, with an outer diameter of 4-8 nm, purity >98%, length of 0.5-2 μm, and specific surface area of ​​380-550 m² / g. 2 / g; Samarium cobalt powder, particle size 200 mesh; Neodymium iron boron powder, particle size 200 mesh; Yttrium iron garnet powder, particle size 200 mesh; Wave absorption and transmission performance: The CST electromagnetic simulation software was used to simulate the electromagnetic wave under perpendicular incidence to measure the transmittance and reflection loss of each material. Peel strength test: Peel strength test is performed using a peel testing machine.

[0040] Example 1 Polyethylene and polyhydroxyethyl methacrylate were mixed in a mass ratio of 1:1 and then extruded into a film with a thickness of 0.15 mm to obtain a wave-transparent substrate layer. 5g of multi-walled carbon nanotubes, 35g of samarium cobalt powder and 60g of polyurethane were mixed and then added to 200g of N-methylpyrrolidone solvent. 1.5g of dispersant KH550 and 15g of blocked isocyanate curing agent Y-311EA were added and mixed. After shearing and ball milling, the shearing speed was 1500 rpm and the shearing time was 10 min. The ball milling speed was 400 rpm and the ball milling time was 20 min to obtain a composite slurry. The composite paste is printed onto the wave-transparent substrate using screen printing technology. The pattern is a cross-shaped array with a period of 10 mm. The paste is then cured in stages at 80℃, 120℃, and 180℃ to form a 0.1 mm thick functional layer, resulting in an integrated electromagnetic wave absorbing and penetrating material.

[0041] Tests showed that the electromagnetic wave absorbing and penetrating integrated material exhibits a wave transmission window at 2.5GHz with a wave transmission rate of 96.2%; within the 8~18GHz frequency band, the reflection loss is better than -10dB, and the peeling force is 12.53kgf.

[0042] Example 2 Polyethylene and polyhydroxyethyl methacrylate were mixed at a mass ratio of 7:3 and then extruded into a 0.1 mm thick film to obtain a wave-transparent substrate layer. 2g of multi-walled carbon nanotubes, 15g of neodymium iron boron powder and 40g of epoxy resin were mixed and then added to 145g of N-methylpyrrolidone solvent. 3g of dispersant KH550 and 10g of blocked isocyanate curing agent Y-311EA were added and mixed. After shearing and ball milling, the shearing speed was 1500 rpm and the shearing time was 20 min. The ball milling speed was 400 rpm and the ball milling time was 30 min to obtain a composite slurry. The composite paste is printed onto the wave-transparent substrate using screen printing technology. The pattern is a square array with a period of 10 mm. The paste is then cured in stages at 80℃, 120℃ and 180℃ to form a 0.05 mm thick functional layer, resulting in an integrated electromagnetic wave absorbing and penetrating material.

[0043] Tests showed that the electromagnetic wave absorbing and penetrating integrated material exhibited a wave transmission window at 4GHz with a wave transmission rate of 93.6%; within the 12~18GHz frequency band, the reflection loss was better than -10dB, and the peeling force was 13.28kgf.

[0044] Example 3 Polypropylene and poly(hydroxyethyl methacrylate) were mixed in a mass ratio of 1:1 and then extruded into a 0.15 mm thick film to obtain a wave-transparent substrate layer. 10g of multi-walled carbon nanotubes, 45g of yttrium iron garnet powder and 70g of epoxy modified silicone resin were mixed and then added to 230g of N-methylpyrrolidone solvent. 4g of dispersant KH550 and 17.5g of blocked isocyanate curing agent Y-311EA were added and mixed. After shearing and ball milling, the shearing speed was 1500 rpm and the shearing time was 25 min. The ball milling speed was 400 rpm and the ball milling time was 40 min to obtain a composite slurry. The composite paste is printed onto the wave-transparent substrate using screen printing technology. The pattern is a circular array with a period of 10 mm. The mixture is then cured in stages at 80℃, 120℃ and 180℃ to form a 0.15 mm thick functional layer, resulting in an integrated electromagnetic wave absorbing and penetrating material.

[0045] Tests showed that the electromagnetic wave absorbing and penetrating integrated material exhibited a wave transmission window at 5.5 GHz with a wave transmission rate of 96.2%; within the 8~12 GHz frequency band, the reflection loss was better than -10 dB, and the peeling force was 12.95 kgf.

[0046] Example 4 Polyethylene and polyhydroxyethyl methacrylate were mixed in a mass ratio of 1:1 and then extruded into a film with a thickness of 0.15 mm to obtain a wave-transparent substrate layer. 5g of multi-walled carbon nanotubes, 35g of samarium cobalt powder and 60g of epoxy-modified silicone resin were mixed and then added to 200g of N-methylpyrrolidone solvent. 1.5g of dispersant KH550 and 15g of blocked isocyanate curing agent Y-311EA were added and mixed. After shearing and ball milling, the shearing speed was 1500 rpm and the shearing time was 10 min. The ball milling speed was 400 rpm and the ball milling time was 20 min to obtain a composite slurry. The composite paste is printed onto the wave-transparent substrate using screen printing technology. The pattern is a cross-shaped array with a period of 10 mm. The paste is then cured in stages at 80℃, 120℃, and 180℃ to form a 0.1 mm thick functional layer, resulting in an integrated electromagnetic wave absorbing and penetrating material.

[0047] Tests showed that the electromagnetic wave absorbing and penetrating integrated material exhibited a wave transmission window at 2.5 GHz with a wave transmission rate of 96.2%; within the 8-18 GHz frequency band, the reflection loss was better than -10 dB, and the peel strength was 13.19 kgf.

[0048] Example 5 Polyethylene and polyhydroxyethyl methacrylate were mixed in a mass ratio of 1:1 and then extruded into a film with a thickness of 0.15 mm to obtain a wave-transparent substrate layer. 5g of multi-walled carbon nanotubes, 35g of samarium cobalt powder, 20g of polyurethane, and 40g of epoxy-modified silicone resin were mixed and then added to 200g of N-methylpyrrolidone solvent. 1.5g of dispersant KH550 and 15g of blocked isocyanate curing agent Y-311EA were added and mixed. After shearing and ball milling, the shearing speed was 1500 rpm and the shearing time was 10 min. The ball milling speed was 400 rpm and the ball milling time was 20 min to obtain a composite slurry. The composite paste is printed onto the wave-transparent substrate using screen printing technology. The pattern is a cross-shaped array with a period of 10 mm. The paste is then cured in stages at 80℃, 120℃, and 180℃ to form a 0.1 mm thick functional layer, resulting in an integrated electromagnetic wave absorbing and penetrating material.

[0049] Tests showed that the electromagnetic wave absorbing and penetrating integrated material exhibits a wave transmission window at 2.5GHz with a wave transmission rate of 96.2%; within the 8-18GHz frequency band, the reflection loss is better than -10dB, and the peeling force is 15.83kgf.

[0050] Example 6 Polyethylene and polyhydroxyethyl methacrylate were mixed in a mass ratio of 1:1 and then extruded into a film with a thickness of 0.15 mm to obtain a wave-transparent substrate layer. 5g of multi-walled carbon nanotubes, 35g of samarium cobalt powder, 15g of polyurethane, and 45g of epoxy-modified silicone resin were mixed and then added to 200g of N-methylpyrrolidone solvent. 1.5g of dispersant KH550 and 15g of blocked isocyanate curing agent Y-311EA were added and mixed. After shearing and ball milling, the shearing speed was 1500 rpm and the shearing time was 10 min. The ball milling speed was 400 rpm and the ball milling time was 20 min to obtain a composite slurry. The composite paste is printed onto the wave-transparent substrate using screen printing technology. The pattern is a cross-shaped array with a period of 10 mm. The paste is then cured in stages at 80℃, 120℃, and 180℃ to form a 0.1 mm thick functional layer, resulting in an integrated electromagnetic wave absorbing and penetrating material.

[0051] Tests showed that the electromagnetic wave absorbing and penetrating integrated material exhibited a wave transmission window at 2.5GHz with a wave transmission rate of 96.2%; within the 8-18GHz frequency band, the reflection loss was better than -10dB, and the peel strength was 16.07kgf.

[0052] Example 7 Polyethylene and polyhydroxyethyl methacrylate were mixed in a mass ratio of 1:1 and then extruded into a film with a thickness of 0.15 mm to obtain a wave-transparent substrate layer. 5g of multi-walled carbon nanotubes, 35g of samarium cobalt powder, 10g of polyurethane, and 50g of epoxy-modified silicone resin were mixed and then added to 200g of N-methylpyrrolidone solvent. 1.5g of dispersant KH550 and 15g of blocked isocyanate curing agent Y-311EA were added and mixed. After shearing and ball milling, the shearing speed was 1500 rpm and the shearing time was 10 min. The ball milling speed was 400 rpm and the ball milling time was 20 min to obtain a composite slurry. The composite paste is printed onto the wave-transparent substrate using screen printing technology. The pattern is a cross-shaped array with a period of 10 mm. The paste is then cured in stages at 80℃, 120℃, and 180℃ to form a 0.1 mm thick functional layer, resulting in an integrated electromagnetic wave absorbing and penetrating material.

[0053] Tests showed that the electromagnetic wave absorbing and penetrating integrated material exhibited a wave transmission window at 2.5 GHz with a wave transmission rate of 96.2%; within the 8-18 GHz frequency band, the reflection loss was better than -10 dB, and the peeling force was 14.51 kgf.

[0054] Example 8 Polyethylene and polyhydroxyethyl methacrylate were mixed in a mass ratio of 1:1 and then extruded into a film with a thickness of 0.15 mm to obtain a wave-transparent substrate layer. 5g of multi-walled carbon nanotubes, 35g of samarium cobalt powder, 30g of polyurethane, and 30g of epoxy-modified silicone resin were mixed and then added to 200g of N-methylpyrrolidone solvent. 1.5g of dispersant KH550 and 15g of blocked isocyanate curing agent Y-311EA were added and mixed. After shearing and ball milling, the shearing speed was 1500 rpm and the shearing time was 10 min. The ball milling speed was 400 rpm and the ball milling time was 20 min to obtain a composite slurry. The composite paste is printed onto the wave-transparent substrate using screen printing technology. The pattern is a cross-shaped array with a period of 10 mm. The paste is then cured in stages at 80℃, 120℃, and 180℃ to form a 0.1 mm thick functional layer, resulting in an integrated electromagnetic wave absorbing and penetrating material.

[0055] Tests showed that the electromagnetic wave absorbing and penetrating integrated material exhibited a wave transmission window at 2.5 GHz with a wave transmission rate of 96.2%; within the 8-18 GHz frequency band, the reflection loss was better than -10 dB, and the peeling force was 14.29 kgf.

[0056] Comparative Example 1 Polyethylene and polyhydroxyethyl methacrylate were mixed in a mass ratio of 1:1 and then extruded into a film with a thickness of 0.15 mm to obtain a wave-transparent substrate layer. 5g of multi-walled carbon nanotubes, 35g of samarium cobalt powder and 60g of polyurethane were mixed and then added to 200g of N-methylpyrrolidone solvent. 1.5g of dispersant KH550 and 15g of blocked isocyanate curing agent Y-311EA were added and mixed. After shearing and ball milling, the shearing speed was 1500 rpm and the shearing time was 10 min. The ball milling speed was 400 rpm and the ball milling time was 20 min to obtain a composite slurry. By using screen printing technology, the composite paste is directly coated onto the wave-transparent substrate layer, and then cured in stages at 80℃, 120℃ and 180℃ to form a 0.1mm thick functional layer, thus obtaining an integrated electromagnetic wave absorbing and penetrating material.

[0057] Tests showed that the electromagnetic wave absorbing and penetrating integrated material had a transmittance of less than 50% across the entire 2-18GHz frequency band, making it unable to form a wave-transmitting window.

[0058] Comparative Example 2 The wave-transparent substrate layer is a 0.15mm thick polyethylene film; 5g of multi-walled carbon nanotubes, 35g of samarium cobalt powder and 60g of polyurethane were mixed and then added to 200g of N-methylpyrrolidone solvent. 1.5g of dispersant KH550 and 15g of blocked isocyanate curing agent Y-311EA were added and mixed. After shearing and ball milling, the shearing speed was 1500 rpm and the shearing time was 10 min. The ball milling speed was 400 rpm and the ball milling time was 20 min to obtain a composite slurry. The composite paste is printed onto the wave-transparent substrate using screen printing technology. The pattern is a cross-shaped array with a period of 10 mm. The paste is then cured in stages at 80℃, 120℃, and 180℃ to form a 0.1 mm thick functional layer, resulting in an integrated electromagnetic wave absorbing and penetrating material.

[0059] Tests showed that the electromagnetic wave absorbing and penetrating integrated material exhibited a wave transmission window at 2.5 GHz with a wave transmission rate of 83.2%; within the 8-18 GHz frequency band, the reflection loss was better than -10 dB, and the peeling force was 6.68 kgf.

[0060] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An electromagnetic wave permeability-absorbing integrated material, characterized in that, It includes a wave-transparent substrate layer and a functional layer arranged from top to bottom. The material of the wave-transparent substrate layer includes the following components in parts by weight: 50-70 parts of polyolefin and 30-50 parts of hydroxy acrylate polymer; The material of the functional layer includes the following components in parts by weight: 2-10 parts carbon nanotubes, 15-45 parts rare earth materials, and 40-70 parts polymer adhesive. The pattern of the functional layer is a periodic array structure.

2. The electromagnetic wave absorbing integrated material according to claim 1, characterized in that, The electromagnetic wave transmission-absorbing integrated material has a transmittance of >90% in the target frequency band within the 0~6GHz frequency range, and an absorption rate better than -10dB in other frequency bands.

3. The electromagnetic wave absorbing integrated material according to claim 1, characterized in that, The hydroxyacrylate polymers include one or more of the following: hydroxyethyl polyacrylate, hydroxyethyl polymethacrylate, hydroxypropyl polyacrylate, hydroxypropyl polymethacrylate, hydroxybutyl polyacrylate, and hydroxybutyl polymethacrylate.

4. The electromagnetic wave absorbing integrated material according to claim 1, characterized in that, The carbon nanotubes include one or both of single-walled carbon nanotubes and multi-walled carbon nanotubes.

5. The electromagnetic wave absorbing integrated material according to claim 1, characterized in that, The rare earth material includes one or more of samarium cobalt, neodymium iron boron, or yttrium iron garnet.

6. The electromagnetic wave absorbing integrated material according to claim 1, characterized in that, The polymer adhesive includes one or more of polyurethane, epoxy resin, and epoxy-modified silicone resin.

7. The electromagnetic wave absorbing and penetrating integrated material according to claim 6, characterized in that, The polymer adhesive comprises a mixture of polyurethane and epoxy-modified silicone resin in a mass ratio of 1:2 to 3.

8. The method for preparing the electromagnetic wave permeability-absorbing integrated material according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Polyolefin and hydroxy acrylate polymer are mixed and extruded into a film to obtain a wave-transparent substrate layer; Carbon nanotubes, rare earth materials and polymer adhesives are mixed and then added to a solvent. Dispersant and curing agent are added and mixed evenly to obtain a composite slurry. S2. The mixed slurry is coated on the wave-transparent substrate layer and cured to form a functional layer, thus obtaining an integrated electromagnetic wave absorbing and penetrating material.

9. The method for preparing the electromagnetic wave permeation-absorbing integrated material according to claim 8, characterized in that, In step S2, the coating is performed according to a pattern of a periodic array structure.

10. The application of the electromagnetic wave absorbing and penetrating integrated material according to any one of claims 1 to 7 or the electromagnetic wave absorbing and penetrating integrated material prepared by the preparation method according to any one of claims 8 to 9, characterized in that, The applications include those in stealth radomes, electromagnetic compatibility devices, or communication devices.