Broadband wave-absorbing and anti-bullet integrated material and preparation method thereof

Abstract

The invention relates to a broadband wave-absorbing and anti-bullet integrated material and a preparation method thereof. The broadband wave-absorbing and anti-bullet integrated material sequentially comprises an outer skin layer, a wave-absorbing and anti-bullet layer and an inner skin layer, the wave-absorbing anti-elastic layer comprises a plurality of anti-elastic plate layers and wave-absorbing material layers arranged among the plurality of anti-elastic plate layers; the anti-elastic plate layer is a high-density polyethylene fiber anti-elastic plate layer; the wave-absorbing material layer is of a hollowed-out woven structure. According to the broadband wave-absorbing and anti-bullet integrated material, the broadband wave-absorbing and anti-bullet integrated effect is achieved, the advantages of being small in thickness, low in surface density and the like are further achieved, and the maximum radar reflectivity of the broadband wave-absorbing and anti-bullet integrated wave-absorbing material is-10 dB or below within the range of 2 GHz to 18 GHz and 26.5 GHz to 40 GHz.

Description

Technical Field

[0001] The invention belongs to the technical field of wave-absorbing materials, and in particular relates to a broadband wave-absorbing and anti-ballistic integrated material and a preparation method thereof. Background Art

[0002] With the continuous advancement of informatization, ground equipment is facing attacks from various light and heavy weapons, and necessary measures need to be taken to make the equipment bulletproof to protect the safety of personnel or equipment in the vehicle. It is difficult for a single type of material to meet the requirements, which requires adding new features to the equipment in terms of multifunctional integration, combining electromagnetic and physical protection capabilities to protect the equipment to the maximum extent.

[0003] Wideband wave-absorbing and anti-ballistic integrated materials combine the functions of wave-absorbing and anti-ballistic. If the wave-absorbing material and the anti-ballistic material can be reasonably combined and designed in a coordinated manner, so that both can play a role in the same material system, it can avoid focusing on a single performance and increasing the thickness and weight of the material system. This is an important development direction for equipment designed for lightweight needs.

[0004] In summary, it is very necessary to provide a broadband wave-absorbing and anti-ballistic integrated material and a preparation method thereof. Summary of the invention

[0005] In order to solve one or more technical problems existing in the prior art, the present invention provides a broadband wave-absorbing and anti-ballistic integrated material and a preparation method thereof.

[0006] In a first aspect, the present invention provides a broadband wave-absorbing and ballistic-resistant integrated material, which comprises an outer skin layer, a wave-absorbing and ballistic-resistant layer and an inner skin layer in sequence; the wave-absorbing and ballistic-resistant layer comprises a multi-layer ballistic-resistant plate layer and a wave-absorbing material layer arranged between the multi-layer ballistic-resistant plate layers; the ballistic-resistant plate layer is a high-density polyethylene fiber ballistic-resistant plate layer; and the wave-absorbing material layer is a hollow woven structure.

[0007] Preferably, the thickness of the broadband radar absorbing and anti-ballistic integrated material is 25-40 mm; and / or the maximum value of the radar reflectivity of the broadband radar absorbing and anti-ballistic integrated material in the range of 2-18 GHz and 26.5-40 GHz is less than -10 dB.

[0008] Preferably, the absorbing material layer is prepared by first using fibers to form a hollow woven structure, and then compounding the absorbing material on the fiber surface of the hollow woven structure; preferably, the absorbing material is a dielectric loss material or a magnetic loss material.

[0009] Preferably, 1 to 2 layers of wave absorbing material are arranged between every two adjacent anti-ballistic plate layers.

[0010] Preferably, the thickness of each anti-ballistic board layer is 1-4 mm; the resistance of each absorbing material layer is 20-1000Ω; and / or the thickness of each absorbing material layer is 0.05-0.1 mm.

[0011] Preferably, the outer skin layer is a fiber cloth formed by one or more fiber materials selected from aramid fiber material, glass fiber material, and quartz fiber material; and / or the relative dielectric constant of the outer skin layer is 1.5-3 and the thickness is 0.2-0.5 mm.

[0012] Preferably, the inner skin layer is a carbon fiber layer or a metal layer, preferably, the metal layer is an aluminum plate layer; and / or the thickness of the inner skin layer is 0.4-0.8 mm.

[0013] Preferably, the outer skin layer and the wave-absorbing and anti-ballistic layer, the wave-absorbing and anti-ballistic layer and the inner skin layer, and the anti-ballistic plate layer and the wave-absorbing material layer are all bonded by low-dielectric resin.

[0014] Preferably, the low dielectric resin is one or more of epoxy resin, bismaleimide resin and polyphenylene ether resin.

[0015] In a second aspect, the present invention provides a method for preparing the broadband wave-absorbing and ballistic-resistant integrated material according to the first aspect of the present invention, the method comprising the following steps:

[0016] (1) stacking the outer skin layer, the radar-absorbing and anti-ballistic layer, and the inner skin layer in sequence into a laminated structure;

[0017] (2) Vacuum-introducing a low-dielectric resin between the outer skin layer and the wave-absorbing and anti-ballistic layer, between the wave-absorbing and anti-ballistic layer and the inner skin layer, and between the anti-ballistic plate layer and the wave-absorbing material layer, and vacuum-introducing and molding the resin to obtain a broadband wave-absorbing and anti-ballistic integrated material.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects:

[0019] (1) The broadband wave-absorbing and ballistic-resistant integrated material provided by the present invention is a broadband wave-absorbing and ballistic-resistant structural integrated lightweight material that is particularly suitable for ground equipment to resist ballistics. The present invention can complement the ballistic-resistant plate layer by reasonably designing the structure and layout of the wave-absorbing material layer, which can effectively avoid the problem of excessive material accumulation and mutual interference of their respective performances when they are designed independently, thereby reducing the redundancy of thickness and weight. The present invention adopts an integrated molding design of the laminated structure of ballistic-resistant material and wave-absorbing material, and reasonably combines the wave-absorbing material and the ballistic-resistant material, which can not only realize multi-functional integration, but also ensure the effectiveness of the function and the optimization of the overall performance while meeting the lightweight requirements. This is an important development direction for equipment oriented to lightweight design.

[0020] (2) The wave-absorbing and anti-ballistic layer of the present invention is composed of a multi-layer anti-ballistic board layer and a wave-absorbing material layer arranged between the multi-layer anti-ballistic board layers, and the anti-ballistic board layer adopts a high-density polyethylene fiber anti-ballistic board, and the wave-absorbing material layer is designed as a hollow woven structure. The present invention finds that the combination of the high-density polyethylene fiber anti-ballistic board and the hollow woven wave-absorbing material layer fully utilizes the high anti-elasticity and low-density characteristics of the high-density polyethylene (HDPE) fiber material and the multiple reflection and wave-absorbing advantages of the hollow woven structure to form a broadband wave-absorbing and anti-ballistic integrated material with optimized performance. This coordinated design effectively achieves the lightweight and high performance of the material while ensuring the wave-absorbing and anti-ballistic performance. Integration meets the dual needs of modern equipment for stealth performance and protection performance; in addition, the present invention finds that HDPE fiber is a non-conductive polymer material with a lower dielectric constant and loss factor. Compared with bullet-proof plates made of metal materials, ceramic materials or carbon fiber composite materials, this makes it easier for electromagnetic waves to penetrate HDPE fibers without significant reflection or shielding effects. The present invention arranges an absorbing material layer with a hollow woven structure between the high-density polyethylene fiber bullet-proof plates. The HDPE fiber bullet-proof plates will not produce unnecessary reflections with the absorbing material layer, ensuring that electromagnetic waves effectively enter the absorbing material layer with a hollow woven structure, achieving higher absorption The dielectric properties of HDPE fiber enable it to achieve better electromagnetic impedance matching when combined with the hollow woven structure absorbing material layer, reduce electromagnetic wave reflection, and improve absorbing performance. In contrast, if other materials are used to make anti-ballistic plates, it may cause impedance mismatch, increase reflection loss, and reduce the overall absorbing effect of the material. The present invention designs the absorbing material layer as a hollow woven structure. Compared with other structures (such as dense solid structure or needle-punched woven structure or puncture woven structure, etc.), the present invention finds that the hollow woven structure can form complex multiple reflection paths inside the material, and the incident electromagnetic waves undergo multiple reflections in the pores and intersections of the hollow woven structure. Secondary reflection, scattering and refraction make the energy be gradually absorbed, thereby effectively expanding the absorbing frequency band and improving the broadband absorbing effect. The hollow woven structure provides controllable porosity, which makes the overall impedance matching of the absorbing material closer to the air and the external environment, reduces the reflection of electromagnetic waves, and exhibits excellent absorbing performance especially in the broadband range. The hollow woven structure has good stress dispersion characteristics under the action of external impact load. The impact energy can be evenly dispersed to the entire absorbing material layer through the pores of the hollow woven structure, avoiding local excessive stress leading to material failure, thereby forming a synergistic protection effect with the HDPE fiber anti-ballistic plate and improving the anti-ballistic performance.

[0021] (3) The thickness of each layer of the wave absorbing and anti-ballistic layer of the present invention can be designed separately. The wave absorbing and anti-ballistic layer is composited with a wave absorbing material layer of a hollow woven structure. The thickness of each layer, the electromagnetic parameters of the wave absorbing material layer and the hollow part work together to make the entire wave absorbing body match the impedance of the free space. The design of the wave absorbing and anti-ballistic layer of the present invention can meet both the requirements of the wave absorbing function and the requirements of the anti-ballistic function. The inner skin layer of the present invention is a carbon fiber layer or a metal layer, which is used to reflect electromagnetic waves not absorbed by the upper layer. The electromagnetic waves not absorbed by the upper layer can be reflected back to the wave absorbing and anti-ballistic layer, so that the electromagnetic waves are secondary propagated and absorbed in the wave absorbing material, thereby improving the overall wave absorbing performance. In the present invention, the outer skin layer, the wave absorbing and anti-ballistic layer and the inner skin layer are composited with a low dielectric resin. The composite process can be, for example, vacuum introduction.

[0022] (4) Through the design of the present invention, the broadband radar absorbing and anti-ballistic integrated material of the present invention achieves the effects of broadband radar absorbing and anti-ballistic integration, and realizes the advantages of thin thickness and low surface density. The thickness of the broadband radar absorbing and anti-ballistic integrated material of the present invention is 25-40 mm, and the maximum value of the radar reflectivity in the range of 2-18 GHz and 26.5-40 GHz is less than -10 dB. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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 or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are 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.

[0024] Figure 1 A schematic diagram of the structure of the broadband wave-absorbing and anti-ballistic integrated material provided by the present invention; wherein the upper layer (upper surface layer) is an outer skin layer, the middle layer is a wave-absorbing and anti-ballistic layer, and the lower layer (lower surface layer) is an inner skin layer;

[0025] Figure 2 is the reflectivity test value of the broadband radar absorbing and anti-ballistic integrated material in Example 1 of the present invention in the range of 2-18 GHz;

[0026] Figure 3 is the reflectivity test value of the broadband wave absorbing and anti-ballistic integrated material in Example 1 of the present invention in the range of 26.5-40 GHz; Figure 2 and Figure 3 In the figure, the horizontal axis Frequency represents the frequency, and the vertical axis Reflectivity represents the reflectivity. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are 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 work are within the scope of protection of the present invention.

[0028] In a first aspect, the present invention provides a broadband wave-absorbing and ballistic-resistant integrated material, which comprises an outer skin layer (also referred to as an outer skin), a wave-absorbing and ballistic-resistant layer and an inner skin layer (also referred to as an inner skin) in sequence. Specifically, the broadband wave-absorbing and ballistic-resistant integrated material of the present invention is an integral layered structure formed by an outer skin layer, a wave-absorbing and ballistic-resistant layer and inner and outer skin layers stacked and connected in sequence; the wave-absorbing and ballistic-resistant layer comprises a plurality of ballistic-resistant plate layers and a wave-absorbing material layer arranged between the plurality of ballistic-resistant plate layers; the ballistic-resistant plate layer is a high-density polyethylene fiber ballistic-resistant plate layer. In the present invention, the high-density polyethylene fiber ballistic-resistant plate layer is made of high-density polyethylene fibers; the wave-absorbing material layer is a hollow woven structure.

[0029] In the present invention, the broadband wave-absorbing and anti-ballistic integrated material can be prepared by an integrated vacuum induction molding process to achieve the effects of broadband wave absorption and anti-ballistic integration; the broadband wave-absorbing and anti-ballistic integrated material in the present invention comprises an outer skin layer, a wave-absorbing and anti-ballistic layer and an inner skin layer in sequence along the propagation direction of electromagnetic waves, the outer skin layer is used as the outermost layer, directly facing the incident wave direction of the electromagnetic wave, so the outer skin requires high wave transmittance; the inner skin layer is at the bottom layer, in contact with the surface of the wave-absorbing and anti-ballistic layer, and reflects the electromagnetic waves that have not been absorbed after passing through the outer skin layer and the wave-absorbing and anti-ballistic layer in sequence, so that they are reflected again to the incident direction for re-absorption, and so on, until more electromagnetic waves are lost internally and the echo is reduced.

[0030] The broadband wave-absorbing and ballistic-resistant integrated material provided by the present invention is a broadband wave-absorbing and ballistic-resistant structural integrated lightweight material that is particularly suitable for ground equipment to resist ballistics. The present invention can complement the ballistic-resistant plate layer by reasonably designing the structure and layout of the wave-absorbing material layer, which can effectively avoid the problem of excessive material accumulation and mutual interference of their respective performances when they are designed independently, thereby reducing the redundancy of thickness and weight. The present invention adopts an integrated molding design of the laminated structure of ballistic-resistant material and wave-absorbing material, and reasonably combines the wave-absorbing material and the ballistic-resistant material, which can not only realize multi-functional integration, but also ensure the effectiveness of the function and the optimization of the overall performance while meeting the lightweight requirements. This is an important development direction for equipment oriented to lightweight design.

[0031] The wave-absorbing and anti-ballistic layer of the present invention is composed of a multi-layer anti-ballistic board layer and a wave-absorbing material layer arranged between the multi-layer anti-ballistic board layers, and the anti-ballistic board layer adopts a high-density polyethylene fiber anti-ballistic board, and the wave-absorbing material layer is designed as a hollow woven structure. The present invention finds that the combination of the high-density polyethylene fiber anti-ballistic board and the hollow woven wave-absorbing material layer fully utilizes the high anti-elasticity and low-density characteristics of the high-density polyethylene (HDPE) fiber material and the multiple reflection and wave-absorbing advantages of the hollow woven structure to form a broadband wave-absorbing and anti-ballistic integrated material with optimized performance. This collaborative design effectively realizes the lightweight and high-performance integration of materials while ensuring the wave-absorbing and anti-ballistic performance. It meets the dual needs of modern equipment for stealth performance and protective performance; in addition, the present invention finds that HDPE fiber is a non-conductive polymer material with a lower dielectric constant and loss factor. Compared with bullet-proof plates made of metal materials, ceramic materials or carbon fiber composite materials, this makes it easier for electromagnetic waves to penetrate HDPE fibers without significant reflection or shielding effects. The present invention arranges an absorbing material layer with a hollow woven structure between the high-density polyethylene fiber bullet-proof plates. The HDPE fiber bullet-proof plates will not produce unnecessary reflections with the absorbing material layer, ensuring that electromagnetic waves effectively enter the absorbing material layer with a hollow woven structure, achieving a higher absorbing effect. The dielectric properties of HDPE fiber enable it to achieve better electromagnetic impedance matching when combined with the hollow woven structure absorbing material layer, reduce electromagnetic wave reflection, and improve absorbing performance. In contrast, if other materials are used to make anti-ballistic plates, it may cause impedance mismatch, increase reflection loss, and reduce the overall absorbing effect of the material. The present invention designs the absorbing material layer as a hollow woven structure. Compared with other structures (such as dense solid structure or needle woven structure or puncture woven structure, etc.), the present invention finds that the hollow woven structure can form complex multiple reflection paths inside the material, and the incident electromagnetic wave occurs multiple times in the pores and intersections of the hollow woven structure. Reflection, scattering and refraction make the energy gradually absorbed, thereby effectively expanding the absorbing frequency band and improving the broadband absorbing effect. The hollow woven structure provides a controllable porosity, which makes the impedance matching of the absorbing material as a whole closer to the air and the external environment, reduces the reflection of electromagnetic waves, and exhibits excellent absorbing performance in a wide frequency range. The hollow woven structure has good stress dispersion characteristics under the action of external impact loads. The impact energy can be evenly dispersed to the entire absorbing material layer through the pores of the hollow woven structure, avoiding local excessive stress leading to material failure, thereby forming a synergistic protection effect with the HDPE fiber anti-ballistic plate and improving anti-ballistic performance. Through the design of the present invention, the broadband absorbing and anti-ballistic integrated material of the present invention achieves the effect of broadband absorbing and anti-ballistic integration, and realizes its advantages of thin thickness and low surface density. The thickness of the broadband absorbing and anti-ballistic integrated material of the present invention is 25-40mm, and the maximum value of the radar reflectivity in the range of 2-18GHz and 26.5-40GHz is less than -10dB.

[0032] According to some preferred implementations, electromagnetic simulation calculations can be used to further optimize the design of the laminated structure of absorbing materials with different electromagnetic parameters and different grades of anti-ballistic materials, so that it has more excellent broadband absorbing performance.

[0033] According to some preferred embodiments, the thickness of the broadband wave-absorbing and anti-ballistic integrated material is 25-40 mm; and / or the maximum value of the radar reflectivity of the broadband wave-absorbing and anti-ballistic integrated material in the ranges of 2-18 GHz and 26.5-40 GHz is less than -10 dB; in some specific embodiments, the maximum value of the radar reflectivity of the broadband wave-absorbing and anti-ballistic integrated material in the ranges of 2-18 GHz and 26.5-40 GHz is less than -10 dB.

[0034] According to some preferred embodiments, the preparation of the absorbing material layer is: first, a hollow woven structure is made of fibers, and then the absorbing material is composited on the fiber surface of the hollow woven structure; in the present invention, the hollow woven structure is a mesh hollow woven structure; in the present invention, for example, the absorbing material is coated and / or scraped on the fiber surface of the hollow woven structure to form the absorbing material layer. In the present invention, the use of a hollow woven structure is also conducive to achieving air permeability and adhesive permeability; in the present invention, preferably, the fiber used in the hollow woven structure is glass fiber, and the absorbing material is carbon black or modified carbon black; the absorbing material coated in the present invention will also penetrate into the hollow woven structure. The present invention does not specifically limit the thickness of the coated absorbing material, and those skilled in the art can conventionally select it, for example, it can be 0.05-0.1 mm; the present invention has no special limitation on carbon black or modified carbon black, and products that can be directly purchased or products synthesized by existing methods can be used.

[0035] According to some preferred embodiments, 1 to 2 layers (eg 1 or 2 layers) of wave absorbing material layers are arranged between every two adjacent anti-ballistic plate layers.

[0036] The present invention adopts a method of superimposing a plurality of single-layer anti-ballistic plate layers with an absorbing material layer to form an overall absorbing and anti-ballistic layer, which is more beneficial to improving the absorbing and anti-ballistic effects. The interaction between the layers can play a certain buffering role on the impact force. More importantly, the absorbing material layer is arranged between the anti-ballistic plate layers, which is beneficial to improving the broadband absorbing performance. In some specific embodiments, for example, the absorbing and anti-ballistic plate can adopt a single-layer anti-ballistic layer with a thickness of 4 mm, and the number is 6 layers; an outer skin layer with a thickness of 0.2 mm is arranged on the top, a absorbing material layer with a thickness of 0.05 mm is arranged between every two layers of anti-ballistic plates, and an inner skin layer with a thickness of 0.6 mm is arranged below, forming a broadband absorbing and anti-ballistic integrated material with an overall thickness of 25.05 mm; in some more preferred designs, a single anti-ballistic plate layer with a thickness of 1 mm / 1.5 mm / 2 mm is used for multi-layer superposition, and one or more absorbing material layers are arranged at intervals to form an absorbing and anti-ballistic layer.

[0037] According to some preferred embodiments, the thickness of each ballistic sheet layer is 1 to 4 mm (e.g., 1, 1.5, 2, 2.5, 3, 3.5 or 4 mm); the resistance (resistance value) of each absorbing material layer is 20-1000 Ω (e.g., 20, 50, 80, 100, 200, 300, 400, 500, 600, 700, 800, 900 or 1000 Ω); and / or the thickness of each absorbing material layer is 0.05 to 0.1 mm (e.g., 0.05 or 0.1 mm).

[0038] In the present invention, the parameters of each absorbing material layer, including resistance and film thickness, etc., can be the same or different, and the impedance matching characteristics of the entire broadband absorbing and anti-ballistic integrated material can be adjusted; in the present invention, the thickness of each anti-ballistic plate layer, the resistance and thickness of each absorbing material layer are obtained through a large number of experimental optimization designs. Preferably, the thickness of each anti-ballistic plate layer is 1 to 4 mm, the resistance of each absorbing material layer is 20-1000Ω, and the thickness of each absorbing material layer is 0.05 to 0.1 mm, which is conducive to obtaining a broadband absorbing and anti-ballistic integrated material with better broadband absorbing performance and anti-ballistic performance.

[0039] According to some preferred embodiments, the outer skin layer has high wave transmission performance and stable physical and chemical properties. Preferably, the outer skin layer is a fiber cloth formed by one or more fiber materials selected from aramid fiber material, glass fiber material, and quartz fiber material; and / or the relative dielectric constant of the outer skin layer is 1.5-3 and the thickness is 0.2-0.5 mm.

[0040] According to some preferred embodiments, the inner skin layer is a carbon fiber layer or a metal layer, preferably, the metal layer is an aluminum plate layer (also referred to as an aluminum plate conductive reflective layer); and / or the thickness of the inner skin layer is 0.4 to 0.8 mm.

[0041] According to some preferred embodiments, the outer skin layer and the wave-absorbing and anti-ballistic layer, the wave-absorbing and anti-ballistic layer and the inner skin layer, and the anti-ballistic plate layer and the wave-absorbing material layer are bonded by means of a low dielectric resin; in the present invention, the bonding process is, for example, vacuum introduction.

[0042] According to some preferred embodiments, the low dielectric resin is one or more of epoxy resin, bismaleimide resin, and polyphenylene ether resin; the present invention does not specifically limit epoxy resin, bismaleimide resin, and polyphenylene ether resin, and epoxy resin, bismaleimide resin, and polyphenylene ether resin that can be used as an adhesive can be used.

[0043] According to some preferred embodiments, the preparation of the absorbing material layer is as follows: first, a hollow woven structure is made of fiber (such as glass fiber), and then a plurality of conical structures are formed on the surface of the hollow woven structure by a plasma etching method, and then the absorbing material is coated on the fiber surface of the hollow woven structure etched with the conical structure; the conical structure can be, for example, a hexagonal pyramid structure or an octagonal pyramid structure; in the present invention, when plasma etching is performed, oxygen and argon are used as etching gases, and the flow rate of oxygen is, for example, 20 to 40 sccm, the flow rate of argon is, for example, 40 to 60 sccm, the etching power is, for example, 140 to 160 W, the RF frequency during etching is, for example, 13.56 MHz, the etching pressure is, for example, 40 to 60 mTorr, the etching time is, for example, 20 to 30 min, and the etching is performed at room temperature of 15 to 35° C., which is conducive to forming a uniform plurality of conical structures on the surface of the hollow woven structure.

[0044] The present invention finds that forming a conical structure on the surface of a hollow woven structure and then coating it with an absorbing material can help improve the broadband absorbing performance of the broadband absorbing and anti-ballistic integrated material. The possible reason is that the concave-convex cone tip array of the conical structure is conducive to causing the incident electromagnetic wave to be reflected, scattered and refracted multiple times on the surface and inside. Each reflection and scattering will extend the propagation path of the electromagnetic wave and increase the number of interactions with the absorbing material, thereby helping to improve the absorption rate of the electromagnetic wave; in addition, the resonance effect formed by the electromagnetic wave between the conical structures also helps the electromagnetic wave to be efficiently absorbed; and the conical structure can be compared to the bionic characteristics of the moth-eye structure. This structural design is conducive to weakening the reflection peak and achieving broadband absorption. Therefore, the broadband absorbing and anti-ballistic integrated material in the present invention can show very excellent absorbing performance under broadband electromagnetic wave conditions while maintaining the original anti-ballistic performance; in addition, in the present invention, it is more preferred that the conical The shaped structure is a hexagonal pyramid structure or an octagonal pyramid structure. The present invention finds that the hexagonal pyramid structure or the octagonal pyramid structure has more corners and sharp edges, which can induce stronger surface scattering and diffraction effects; the sharp edges and corners can cause scattering, reflection and diffraction of electromagnetic waves, and produce multiple reflections and interference effects in different frequency ranges, which are helpful to optimize the absorption of electromagnetic waves, and the hexagonal pyramid structure or the octagonal pyramid structure will form a local electromagnetic field enhancement effect at each corner of the structure due to multiple refractions and reflections. These local field enhancement effects help to absorb more electromagnetic wave energy, especially in a wide frequency range, and can more effectively absorb electromagnetic waves of different frequencies, thereby enhancing the wide-band absorption effect, while the surface of the conical structure is relatively smooth, without the corners of the polygonal structure, so its effects on the scattering, diffraction and reflection of electromagnetic waves are relatively weak, and the improvement of the broadband absorption performance is relatively unobvious.

[0045] In a second aspect, the present invention provides a method for preparing the broadband wave-absorbing and ballistic-resistant integrated material according to the first aspect of the present invention, the method comprising the following steps:

[0046] (1) stacking the outer skin layer, the radar-absorbing and anti-ballistic layer, and the inner and outer skin layers in sequence to form a laminated structure;

[0047] (2) vacuum-introducing a low-dielectric resin between the outer skin layer and the wave-absorbing and anti-ballistic layer, between the wave-absorbing and anti-ballistic layer and the inner skin layer, and between the anti-ballistic plate layer and the wave-absorbing material layer, and performing vacuum-introducing molding to obtain a broadband wave-absorbing and anti-ballistic integrated material; the present invention does not specifically limit the amount of the introduced low-dielectric resin, and a person skilled in the art can conventionally select, for example, the amount of the low-dielectric resin introduced between the two-layer structure is 200-220 g / m 2 × The bonding area between the two layers.

[0048] The present invention will be further described below by way of examples, but the protection scope of the present invention is not limited to these embodiments. The present invention may also have other various embodiments, and those skilled in the art may make various corresponding changes and deformations according to the present invention without departing from the spirit and essence of the present invention, but these corresponding changes and deformations shall all belong to the protection scope of the claims attached to the present invention.

[0049] Example 1

[0050] A broadband wave-absorbing and anti-bullet integrated material, the structure of which is as follows Figure 1 As shown, the overall layered structure is formed by the outer skin layer, the wave absorbing and anti-bullet layer and the inner skin layer. When in use, the outer skin layer faces the direction of electromagnetic wave irradiation, that is, the direction of electromagnetic wave arrival. The specific design and function of each part are as follows:

[0051] The outer skin layer is a fiber cloth formed of quartz fiber material, the relative dielectric constant of which is 1.7±0.2 in the frequency range of 2-18 GHz and 26.5-40 GHz, and the thickness is 0.3±0.05 mm.

[0052] The wave-absorbing and anti-ballistic layer includes 13 single-layer anti-ballistic plate layers, and wave-absorbing material layers are arranged between the single-layer anti-ballistic plates; specifically, the thickness of the single-layer anti-ballistic plate layer bonded to the outer skin layer is 1 mm, and from top to bottom it also includes 2 single-layer anti-ballistic plate layers with a thickness of 1.5 mm, 10 single-layer anti-ballistic plate layers with a thickness of 2 mm, one layer of wave-absorbing material layer is arranged between the 1 mm thick single-layer anti-ballistic plate layer and the 1.5 mm thick single-layer anti-ballistic plate layer, between the 1.5 mm thick single-layer anti-ballistic plate layer and the 1.5 mm thick single-layer anti-ballistic plate layer, and between the 1.5 mm thick single-layer anti-ballistic plate layer and the 2 mm thick single-layer anti-ballistic plate layer, and two layers of wave-absorbing material layers are arranged between the 2 mm thick single-layer anti-ballistic plate layer and the 2 mm thick single-layer anti-ballistic plate layer. Among them, each ballistic-resistant board layer is a high-density polyethylene fiber ballistic-resistant board layer; the absorbing material layer is a hollow woven structure, the resistance of each absorbing material layer is 80Ω, the thickness is 0.05mm, the resistance of every two absorbing material layers is 80Ω, and the overall thickness is 0.1mm; the preparation of the absorbing material layer is: firstly, glass fiber is used to make a hollow woven structure, and then the absorbing material (carbon black) is coated on the surface of the glass fiber of the hollow woven structure.

[0053] The inner skin layer is an aluminum plate conductive reflective layer (aluminum plate layer), and the thickness of the inner skin layer is 0.6±0.05mm.

[0054] The preparation of the broadband wave absorbing and anti-ballistic integrated material in this embodiment is as follows: the outer skin layer, the wave absorbing and anti-ballistic layer and the inner skin layer are stacked in sequence into a laminated structure; low dielectric resin (epoxy resin) is vacuum introduced between the outer skin layer and the wave absorbing and anti-ballistic layer, between the wave absorbing and anti-ballistic layer and the inner skin layer, and between the anti-ballistic plate layer and the wave absorbing material layer included in the laminated structure, and connection is performed through the low dielectric resin, and vacuum introduction molding is performed to obtain the broadband wave absorbing and anti-ballistic integrated material.

[0055] After testing, the reflectivity test results of the broadband wave absorbing and anti-ballistic integrated material in this embodiment are as follows: Figure 2 and Figure 3 As shown, the maximum value of radar reflectivity in the frequency ranges of 2-18 GHz and 26.5-40 GHz is less than -10 dB.

[0056] Example 2

[0057] Embodiment 2 is substantially the same as Embodiment 1, except that:

[0058] Among them, the preparation of the absorbing material layer is as follows: first, a hollow woven structure is made of glass fiber, and then a plurality of hexagonal pyramid structures are formed on the surface of the hollow woven structure by a plasma etching method, and then the absorbing material (carbon black) is coated on the fiber surface of the hollow woven structure etched with the hexagonal pyramid structure; when performing plasma etching, oxygen and argon are used as etching gases, the oxygen flow rate is: 30sccm, the argon flow rate is 50sccm, the etching power is 150W, the RF frequency during etching is 13.56MHz, the etching pressure is 50mTorr, the etching time is 20min, and the etching is carried out at room temperature.

[0059] It was measured that the maximum value of the radar reflectivity of the broadband wave-absorbing and anti-ballistic integrated material described in this embodiment in the frequency ranges of 2-18 GHz and 26.5-40 GHz was less than -15 dB.

[0060] Example 3

[0061] Embodiment 3 is substantially the same as Embodiment 2, except that:

[0062] The preparation of the absorbing material layer is as follows: first, a hollow woven structure is made of glass fiber, then a plurality of conical structures are formed on the surface of the hollow woven structure by a plasma etching method, and then the absorbing material (carbon black) is coated on the fiber surface of the hollow woven structure etched with the conical structure.

[0063] It was measured that the maximum value of the radar reflectivity of the broadband wave-absorbing and anti-ballistic integrated material in this embodiment in the frequency ranges of 2-18 GHz and 26.5-40 GHz was less than -12 dB.

[0064] Comparative Example 1

[0065] Comparative Example 1 is substantially the same as Example 1, except that each bullet-proof plate layer is a UHMWPE (ultra-high molecular weight polyethylene) bullet-proof plate layer.

[0066] It was measured that the maximum value of the radar reflectivity of the integrated wave-absorbing and anti-ballistic material obtained in this comparative example was only less than -5dB in the frequency ranges of 2-18GHz and 26.5-40GHz.

[0067] Comparative Example 2

[0068] Comparative Example 1 is substantially the same as Example 1, except that each bullet-proof plate layer is a ceramic composite bullet-proof plate layer.

[0069] It was measured that the maximum value of the radar reflectivity of the integrated wave-absorbing and anti-ballistic material obtained in this comparative example was only less than -3dB in the frequency ranges of 2-18GHz and 26.5-40GHz.

[0070] Comparative Example 3

[0071] Comparative Example 3 is substantially the same as Example 1, except that:

[0072] The absorbing material layer is a needle-punched woven structure, and the preparation of the absorbing material layer is as follows: firstly, glass fiber is used to make the needle-punched woven structure, and then carbon black is coated on the fiber surface of the needle-punched woven structure.

[0073] It was measured that the maximum value of the radar reflectivity of the integrated wave-absorbing and anti-ballistic material obtained in this comparative example was only less than -5dB in the frequency ranges of 2-18GHz and 26.5-40GHz.

[0074] Comparative Example 4

[0075] A broadband absorbing material, which is an overall layered structure formed by an outer skin layer, an absorbing material layer and an inner skin layer. When in use, the outer skin layer faces the direction of electromagnetic wave irradiation, that is, the direction of electromagnetic wave arrival. The specific design and function of each part are as follows:

[0076] The outer skin layer is a fiber cloth formed of quartz fiber material, the relative dielectric constant of which is 1.7±0.2 in the frequency range of 2-18 GHz and 26.5-40 GHz, and the thickness is 0.3±0.05 mm.

[0077] The absorbing material layer includes 12 single-layer absorbing material layers, each of which is a hollow woven structure, and the resistance of each absorbing material layer is 80Ω and the thickness is 0.05mm; the preparation of the absorbing material layer is: first, glass fiber is used to make a hollow woven structure, and then the absorbing material (carbon black) is coated on the fiber surface of the hollow woven structure.

[0078] The inner skin layer is an aluminum plate conductive reflective layer (aluminum plate layer), and the thickness of the inner skin layer is 0.6±0.05mm.

[0079] The broadband absorbing material in this comparative example is prepared by stacking the outer skin layer, the absorbing material layer and the inner skin layer in sequence into a laminated structure; vacuum introducing a low dielectric resin (epoxy resin) between the outer skin layer and the absorbing material layer and between the absorbing material layer and the inner skin layer included in the laminated structure, and vacuum introducing and molding to obtain the broadband absorbing material.

[0080] It was measured that the maximum value of the radar reflectivity of the absorbing material obtained in this comparative example was only less than -2dB in the frequency ranges of 2-18GHz and 26.5-40GHz.

[0081] Comparative Example 5

[0082] Comparative Example 5 is substantially the same as Example 1, except that:

[0083] The preparation of the wave-absorbing and anti-ballistic layer is as follows: (1) epoxy resin with a mass ratio of 10:90 is evenly dipped on the surface of PE non-woven fabric, and 8 PE non-woven fabrics dipped in epoxy resin are orthogonally laid layer by layer to prepare the anti-ballistic layer; (2) 10 μm-diameter flake ferrite and epoxy resin with a mass ratio of 20:80, 30:70, 40:60, 50:50, and 80:20 are evenly dispersed and evenly scraped on the surface of polyester fiber fabric to prepare a concentration of The electromagnetic wave absorbing layers are 20%, 30%, 40%, 50% and 80% respectively; the anti-ballistic layer described in step (1) and the electromagnetic wave absorbing layers with different concentrations described in step (2) are alternately combined, the anti-ballistic layer is 6 layers, the electromagnetic wave absorbing layer is 5 layers, the concentration of the electromagnetic wave absorbing layer is 20%, 30%, 40%, 50% and 80% from top to bottom respectively, and the wave absorbing anti-ballistic layer is prepared through mold input, pressurization, temperature increase, molding, cooling, pressure reduction and demoulding.

[0084] The preparation of the integrated wave-absorbing and anti-ballistic material in this comparative example is as follows: the outer skin layer, the wave-absorbing and anti-ballistic layer and the inner skin layer are stacked in sequence to form a laminated structure; a low dielectric resin (epoxy resin) is vacuum-introduced between the outer skin layer and the wave-absorbing and anti-ballistic layer and between the wave-absorbing and anti-ballistic layer and the inner skin layer included in the laminated structure, and vacuum-introduced molding is performed to obtain the integrated wave-absorbing and anti-ballistic material.

[0085] It was measured that the maximum value of the radar reflectivity of the integrated wave-absorbing and anti-ballistic material obtained in this comparative example was only less than -4 dB in the frequency ranges of 2-18 GHz and 26.5-40 GHz.

[0086] Comparative Example 6

[0087] Comparative Example 6 refers to Example 2 of CN 104763100 A to obtain a large square cabin panel with radar stealth and bulletproof functions.

[0088] The maximum radar wave reflectivity of the large panel of the cabin is less than -10dB in the range of 4GHz to 18GHz, but the minimum radar reflectivity in the range of 26.5-40GHz is greater than -8dB.

[0089] Parts of the present invention that are not described in detail are well known to those skilled in the art.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A broadband wave-absorbing and anti-ballistic integrated material, characterized in that: The broadband wave-absorbing and anti-ballistic integrated material comprises an outer skin layer, a wave-absorbing and anti-ballistic layer and an inner skin layer in sequence; The wave-absorbing and anti-ballistic layer comprises a plurality of anti-ballistic board layers and a wave-absorbing material layer arranged between the plurality of anti-ballistic board layers; The anti-ballistic board layer is a high-density polyethylene fiber anti-ballistic board layer; The wave absorbing material layer is a hollow woven structure.

2. The broadband wave-absorbing and anti-ballistic integrated material according to claim 1, characterized in that: The thickness of the broadband wave-absorbing and anti-ballistic integrated material is 25-40 mm; and / or The maximum value of the radar reflectivity of the broadband wave-absorbing and anti-ballistic integrated material in the ranges of 2-18 GHz and 26.5-40 GHz is less than -10 dB.

3. The broadband wave-absorbing and anti-ballistic integrated material according to claim 1, characterized in that: The preparation of the wave absorbing material layer is as follows: firstly, fibers are used to form a hollow woven structure, and then the wave absorbing material is compounded on the fiber surface of the hollow woven structure; Preferably, the absorbing material is a dielectric loss material or a magnetic loss material.

4. The broadband wave-absorbing and anti-ballistic integrated material according to claim 1, characterized in that: One to two layers of wave absorbing material are arranged between every two adjacent anti-bullet plate layers.

5. The broadband wave-absorbing and anti-ballistic integrated material according to claim 4, characterized in that: The thickness of each bullet-resistant plate layer is 1 to 4 mm; The resistance of each absorbing material layer is 20-1000Ω; and / or The thickness of each absorbing material layer is 0.05-0.1 mm.

6. The broadband wave-absorbing and anti-ballistic integrated material according to claim 1, characterized in that: The outer skin layer is a fiber cloth formed by one or more fiber materials selected from aramid fiber material, glass fiber material, and quartz fiber material; and / or The relative dielectric constant of the outer skin layer is 1.5-3, and the thickness is 0.2-0.5 mm.

7. The broadband wave-absorbing and anti-ballistic integrated material according to claim 1, characterized in that: The inner skin layer is a carbon fiber layer or a metal layer, preferably, the metal layer is an aluminum plate layer; and / or The thickness of the inner skin layer is 0.4-0.8 mm.

8. The broadband wave-absorbing and anti-ballistic integrated material according to claim 1, characterized in that: The outer skin layer and the wave-absorbing and anti-ballistic layer, the wave-absorbing and anti-ballistic layer and the inner skin layer, and the anti-ballistic plate layer and the wave-absorbing material layer are all bonded by low-dielectric resin.

9. The broadband wave-absorbing and anti-ballistic integrated material according to claim 8, characterized in that: The low dielectric resin is one or more of epoxy resin, bismaleimide resin and polyphenylene ether resin.

10. The method for preparing a broadband radar absorbing and anti-ballistic integrated material according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: (1) stacking the outer skin layer, the radar-absorbing and anti-ballistic layer, and the inner skin layer in sequence into a laminated structure; (2) Vacuum-introducing a low-dielectric resin between the outer skin layer and the wave-absorbing and anti-ballistic layer, between the wave-absorbing and anti-ballistic layer and the inner skin layer, and between the anti-ballistic plate layer and the wave-absorbing material layer, and vacuum-introducing and molding the resin to obtain a broadband wave-absorbing and anti-ballistic integrated material.

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