Multiband infrared stealth composite material and preparation method thereof

Abstract

The present application relates to the technical field of military stealth material, and relates to a multi-band infrared stealth composite material and a preparation method thereof.The present application comprises an outer layer and an inner layer, wherein the outer layer and the inner layer both comprise a substrate layer and a functional plating layer arranged in sequence from outside to inside; the substrate layer is made of aramid fiber and conductive fiber blended together; the surface of the substrate layer is provided with an infrared regulation printing layer made of ITO / ATO composite oxide; the functional plating layer comprises a first aluminum plating layer and a first boron nitride layer arranged in sequence from outside to inside; the first boron nitride layer of the outer layer and the first boron nitride layer of the inner layer are connected by an adhesive layer; and the first aluminum plating layer and the first boron nitride layer are combined in a sequential plating manner.Through blending aramid fiber and conductive fiber, the mechanical properties of the material are ensured; the substrate layer cooperates with the infrared regulation printing layer and the functional plating layer to reduce the emissivity of the overall material and realize effective regulation in a wide band.

Description

Technical Field

[0001] This invention relates to the field of military stealth materials technology, and specifically to a multi-band infrared stealth composite material and its preparation method. Background Technology

[0002] With the rapid development of infrared detection technology, the performance requirements for infrared stealth materials are becoming increasingly stringent. Existing infrared stealth materials have significant shortcomings in key performance aspects such as lightweight design, wide-band tunability, and high mechanical strength. For example, many commercially available infrared stealth materials struggle to control their areal density to 350 g / m². 2 The following limitations fail to meet the equipment's lightweight requirements, which not only increases the equipment's weight but may also affect its mobility and endurance. Regarding wavelength control, existing materials struggle to achieve effective control over a wide 3-14μm band, significantly reducing stealth effectiveness against infrared detection devices of different wavelengths. In terms of mechanical strength, most materials have a strength of less than 400MPa, making them susceptible to damage from external forces during actual use, thus affecting the stability and durability of stealth performance.

[0003] In addition, although traditional sandwich infrared stealth materials can achieve stealth function to a certain extent, the coating and bonding interface are prone to delamination during long-term use, which affects the overall performance of the material. Therefore, developing a multi-band infrared stealth composite material with lightweight, wide-band control and high mechanical strength and its preparation method is of great practical significance. Summary of the Invention

[0004] To address the problems of existing technologies, this invention provides a multi-band infrared stealth composite material and its preparation method.

[0005] The objective of this invention can be achieved through the following technical solutions: A multi-band infrared stealth composite material includes an outer layer and an inner layer. Both the outer and inner layers include a substrate layer and a functional coating layer arranged sequentially from the outside to the inside. The substrate layer is made of a blend of aramid fiber and conductive fiber. An infrared-controlled printing layer is provided on the outer surface of the substrate layer. The infrared-controlled printing layer is made of ITO / ATO composite oxide. The functional coating layer includes a first aluminum plating layer and a first boron nitride layer arranged sequentially from the outside to the inside. The first boron nitride layer of the outer layer and the first boron nitride layer of the inner layer are compositely connected by an adhesive layer. The first aluminum plating layer and the first boron nitride layer are combined and arranged in a sequential plating manner.

[0006] In a further improvement, an intermediate layer is provided between the outer layer and the inner layer. The intermediate layer includes a PET substrate layer, a second aluminum plating layer, and a second boron nitride layer arranged sequentially from top to bottom. The second aluminum plating layer and the second boron nitride layer are combined in a sequential plating manner.

[0007] In a further improvement, the conductive fiber is silver-plated nylon, copper-plated carbon fiber, or MXene-coated polyester material.

[0008] In a further improvement, the aramid fiber content in the substrate layer is 80-95%, the conductive fiber content is 5-20%, and the substrate layer density is 120-180 g / m². 2 .

[0009] Further improvements include an infrared-controlled printing layer with a sheet resistance of <100Ω / Sq, forming a camouflage pattern with a zoned emissivity range of 0.3-0.7.

[0010] In a further improvement, the thickness of the first aluminum layer in the functional coating is 30-80 nm, and the thickness of the first boron nitride layer in the functional coating is 0.5-2 μm.

[0011] In a further improvement, the thickness of the second aluminum plating layer in the intermediate layer is 30-80 nm, and the thickness of the second boron nitride layer in the intermediate layer is 0.5-2 μm.

[0012] In a further improvement, the adhesive layer is primarily composed of flame-retardant polyurethane adhesive, which contains boron nitride or graphene filler, and the thermal conductivity of the flame-retardant polyurethane adhesive is >0.2 W / m·K.

[0013] A method for preparing a multi-band infrared stealth composite material includes the following steps: S1: Substrate layer preparation: 80-95% aramid fiber and 5-20% conductive fiber are blended to produce a surface density of 120-180 g / m². 2 The substrate layer; S2: Preparation of infrared-controlled printing layer: An infrared-controlled printing layer is made using ITO / ATO composite oxide, and a camouflage pattern is formed on the surface of the substrate layer obtained in step S1 by vacuum plating or rotary screen printing process. S3: Functional coating preparation: On the surface of the substrate layer after step S2, a first aluminum layer with a thickness of 30-80nm is first deposited by sequential plating, and then a first boron nitride layer with a thickness of 0.5-2μm is deposited to form a functional coating. S4: Outer and Inner Layer Production: Use the materials from step S3 as semi-finished products for the outer and inner layers, respectively, for later use.

[0014] S5: Two-layer composite: The outer first boron nitride layer and the inner first boron nitride layer are bonded together by an adhesive layer to complete the preparation of multi-band infrared stealth composite material.

[0015] Further improvements, S6: Intermediate layer preparation: After the outer and inner layers are prepared in step S4, an intermediate layer is set. On the PET substrate layer, a second aluminum layer with a thickness of 30-80nm and a second boron nitride layer with a thickness of 0.5-2μm are deposited by sequential plating to form the intermediate layer. S7: Three-layer composite: The outer first boron nitride layer is bonded to the middle PET substrate layer through an adhesive layer, and the inner first boron nitride layer is bonded to the middle second boron nitride layer through an adhesive layer, thus completing the preparation of the multi-band infrared stealth composite material.

[0016] Compared with existing technologies, the beneficial effects of the multi-band infrared stealth composite material and its preparation method of this invention are as follows: In the two-layer multi-band infrared stealth composite material, the outer and inner layers are connected by a coating to achieve synergistic optimization of infrared reflection and thermal conductivity. The blending of aramid and conductive fibers ensures both the material's mechanical properties and imparts conductivity, aiding in the regulation of infrared emissivity. Combined with an infrared-controlled printing layer made of ITO / ATO composite oxide, the emissivity is regulated by controlling sheet resistance and utilizing its selective absorption and emission characteristics in the infrared band, forming a camouflage pattern that further enhances stealth. Simultaneously, the boron nitride and aluminum layers in the functional coatings of the outer and inner layers achieve a double-layer combination, improving infrared reflection performance and providing good thermal stability. In the three-layer multi-band infrared stealth composite material, the outer, middle, and inner layers are connected by a coating through a sandwich gradient coating to achieve synergistic optimization of infrared reflection and thermal conductivity. The middle layer further optimizes the material's reflection and absorption performance in the infrared band. The substrate layer, in conjunction with the infrared-controlled printing layer and the functional coatings, reduces the overall emissivity of the material, achieving effective control over a wide wavelength range. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the two-layer composite structure of the present invention. Figure 2 This is a schematic diagram of the three-layer composite structure of the present invention. In the figure, 1-outer layer, 2-inner layer, 3-substrate layer, 4-functional coating layer, 41-first aluminum plating layer, 42-first boron nitride layer, 5-infrared controlled printing layer, 6-intermediate layer, 61-PET substrate layer, 62-second aluminum plating layer, 63-second boron nitride layer, 7-adhesive layer. Detailed Implementation

[0018] In the description of this invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0019] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] The following describes the embodiments and appendices. Figures 1-2 The technical solution of the present invention will be further described below.

[0021] Example 1 A multi-band infrared stealth composite material includes an outer layer 1 and an inner layer 2. Both the outer layer 1 and the inner layer 2 include a substrate layer 3 and a functional coating layer 4 arranged sequentially from the outside to the inside. The substrate layer 3 is made of a blend of aramid fiber and conductive fiber. An infrared-controlled printing layer 5 is disposed on the outer surface of the substrate layer 3. The infrared-controlled printing layer 5 is made of ITO / ATO composite oxide. The functional coating layer 4 includes a first aluminum plating layer 41 and a first boron nitride layer 42 arranged sequentially from the outside to the inside. The first boron nitride layer 42 of the outer layer 1 and the first boron nitride layer 42 of the inner layer 2 are compositely connected by an adhesive layer 7. The first aluminum plating layer 41 and the first boron nitride layer 42 are combined and disposed in a sequential plating manner. A method for preparing a multi-band infrared stealth composite material includes the following steps: S1: Substrate layer preparation: A blend of 92% aramid fiber and 8% silver-plated nylon conductive fiber is used to produce a surface density of 150 g / m². 2 The substrate layer contains para-aramid fibers with a single filament diameter of 12-15 μm; the conductive fibers have a single filament diameter of 10-12 μm and are woven in a 2 / 2 twill weave using a rapier loom with a warp density of 60 threads / cm and a weft density of 40 threads / cm to form a three-dimensional interwoven structure, thereby enabling the conductive fibers to form a continuous conductive network in the substrate layer. S2: Preparation of Infrared Controlled Printing Layer: An infrared controlled printing layer is prepared using ITO / ATO composite oxide, and a camouflage pattern is formed on the surface of the substrate layer obtained in step S1 by vacuum plating or rotary screen printing. The sheet resistance is controlled to be 80Ω / sq. The molar ratio of In2O3:SnO2:Sb2O5 in the ITO / ATO composite oxide is 85:10:5. Nanoparticles with a particle size of 50-80nm are synthesized by sol-gel method and screen printed to form a camouflage pattern with a thickness of 200-500nm. The doping concentration gradient varies in different regions (Sb content from 3% to 8%) to achieve regional control of mid-wave infrared emissivity of 0.3±0.05 in 3-5μm and long-wave infrared emissivity of 0.6±0.1 in 8-14μm. S3: Preparation of Functional Coating: On the surface of the substrate layer after step S2, a first aluminum coating layer with a thickness of 50 nm and an areal density of approximately 0.05 g / m² is first deposited using a sequential deposition method. 2 Then, a first boron nitride layer with a thickness of 1 μm and an areal density of approximately 1.5 g / m² is deposited. 2 This forms a functional coating. S4: Outer and Inner Layer Production: Use the materials from step S3 as semi-finished products for the outer and inner layers, respectively, for later use; S5: Two-layer composite: The outer first boron nitride layer and the inner first boron nitride layer are bonded together by an adhesive layer, with an areal density of 2 g / m³. 2 The adhesive layer is mainly composed of flame-retardant polyurethane adhesive, and boron nitride filler is added to the flame-retardant polyurethane adhesive to make its thermal conductivity 0.3 W / m・K, thus completing the preparation of multi-band infrared stealth composite material.

[0022] Aramid fibers, characterized by high strength and low density, are blended with conductive fibers to ensure the material's mechanical properties while imparting conductivity, which helps regulate infrared emissivity. The infrared-controlled printing layer, made of ITO / ATO composite oxide, controls emissivity by adjusting sheet resistance and utilizing its selective absorption and emission characteristics in the infrared band, forming a camouflage pattern that further enhances stealth. The first aluminum plating layer has excellent infrared reflectivity, while the first boron nitride layer possesses high hardness, high temperature resistance, and good thermal stability; their combination improves the material's overall performance. The substrate layer, working synergistically with the infrared-controlled printing layer and functional plating, reduces the overall emissivity of the material. The flame-retardant polyurethane adhesive, with boron nitride filler added as an adhesive layer, not only ensures a strong bond between the two layers but also improves the composite material's thermal conductivity and flame-retardant properties. Key Performance Comparison Table The surface density of the second-layer multi-band infrared stealth composite material is approximately 305 g / m². 2It has a tensile strength of approximately 450 MPa, an emissivity of approximately 0.22 in the 3-5 μm region and approximately 0.28 in the 8-14 μm region, and exhibits no delamination after more than 240 hours of damp heat resistance.

[0023] Example 2 A multi-band infrared stealth composite material includes: an outer layer 1 and an inner layer 2, with the outer layer 1 located above the inner layer 2; both the outer layer 1 and the inner layer 2 include a substrate layer 3 and a functional coating layer 4 arranged sequentially from the outside to the inside, with the side furthest from the center being the outer side; the substrate layer 3 is made of a blend of aramid fiber and conductive fiber, and an infrared-controlled printing layer 5 is provided on the outer surface of the substrate layer 3, with the side furthest from the center being the outer side; the infrared-controlled printing layer 5 is made of ITO / ATO composite oxide, and the functional coating layer 4 includes a first aluminum plating layer 41 and a first boron nitride layer 42 arranged sequentially from the outside to the inside, with the side furthest from the center being the outer side; the first boron nitride layer 42 of the outer layer 1 and the first boron nitride layer 42 of the inner layer 2 are compositely connected by an adhesive layer 7, and the first aluminum plating layer 41 and the first boron nitride layer 42 are combined in a sequential plating manner; An intermediate layer 6 is provided between the outer layer 1 and the inner layer 2. The intermediate layer 6 includes a PET substrate layer 61, a second aluminum plating layer 62 and a second boron nitride layer 63 arranged sequentially from top to bottom. The second aluminum plating layer 62 and the second boron nitride layer 63 are combined in a sequential plating manner.

[0024] A method for preparing a multi-band infrared stealth composite material includes the following steps: S1: Substrate layer preparation: A blend of 93% aramid fiber and 7% MXene-coated polyester conductive fiber is used to produce a surface density of 140 g / m². 2 The substrate layer, wherein the aramid fiber is para-aramid with a single filament diameter of 12-15μm and the conductive fiber has a single filament diameter of 8-10μm. It is woven in 2 / 2 twill on a rapier loom with a warp density of 60 threads / cm and a weft density of 40 threads / cm to form a three-dimensional interwoven structure, so that the conductive fiber forms a continuous conductive network in the substrate layer. S2: Preparation of Infrared Controlled Printing Layer: An infrared controlled printing layer is prepared using ITO / ATO composite oxide, and a camouflage pattern is formed on the surface of the substrate layer obtained in step S1 by vacuum plating or rotary screen printing. The sheet resistance is controlled to be 70Ω / sq. The molar ratio of In2O3:SnO2:Sb2O5 in the ITO / ATO composite oxide is 88:8:4. Nanoparticles with a particle size of 50-80nm are synthesized by sol-gel method and screen printed to form a camouflage pattern with a thickness of 200-500nm. The doping concentration gradient varies in different regions (Sb content from 3% to 8%) to achieve regional control of mid-wave infrared emissivity of 0.3±0.05 in 3-5μm and long-wave infrared emissivity of 0.6±0.1 in 8-14μm. S3: Preparation of Functional Coating: On the surface of the substrate layer after step S2, a first aluminum layer with a thickness of 60 nm is first deposited, followed by a first boron nitride layer with a thickness of 1.2 μm, to form the functional coating. The total areal density of the functional coating is approximately 3.1 g / m³. 2 ; S4: Outer and Inner Layer Production: Use the materials from step S3 as semi-finished products for the outer and inner layers, respectively, for later use; S5: Intermediate Layer Preparation: After the outer and inner layers are prepared in step S4, an intermediate layer is set on the PET substrate layer. The surface density of the PET substrate layer is 20 g / m². 2 A second aluminum layer with a thickness of 60 nm and a second boron nitride layer with a thickness of 1.2 μm were deposited using a sequential plating method. The density of the second aluminum layer was approximately 0.06 g / m². 2 The density of the second boron nitride layer is approximately 2.2 g / m³. 2 To form an intermediate layer; S6: Three-layer composite: The outer first boron nitride layer is bonded to the middle PET substrate layer via an adhesive layer. The adhesive layer is primarily composed of flame-retardant polyurethane adhesive, with graphene filler added within it. Due to the two bonding points, the adhesive layer density at each bonding point is 2 g / m³. 2 Total 4g / m 2 To achieve a thermal conductivity greater than 0.35 W / m·K, the first boron nitride layer of the inner layer and the second boron nitride layer of the middle layer are bonded together using an adhesive layer, thus completing the preparation of the multi-band infrared stealth composite material.

[0025] The intermediate layer further enhances the material's performance. The PET substrate layer exhibits excellent flexibility and dimensional stability. The combination of the second aluminum plating layer and the second boron nitride layer, along with the first aluminum plating layer and the first boron nitride layer in the functional coatings of the outer and inner layers, achieves an alternating gradient coating method, further optimizing the material's reflection and absorption performance in the infrared band.

[0026] Adding graphene filler to flame-retardant polyurethane adhesive improves the thermal conductivity and mechanical properties of the adhesive layer, resulting in superior overall performance of the composite material. Key Performance Comparison Table The surface density of the three-layer multi-band infrared stealth composite material is approximately 309 g / m³. 2 It has a tensile strength of approximately 490 MPa, an emissivity of approximately 0.27 in the 3-5 μm range and approximately 0.33 in the 8-14 μm range, and exhibits no delamination after more than 240 hours of damp heat resistance.

[0027] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A multi-band infrared stealth composite material, characterized in that, include: The outer layer and the inner layer each include a substrate layer and a functional coating layer arranged sequentially from the outside to the inside. The substrate layer is made of a blend of aramid fiber and conductive fiber. An infrared-controlled printing layer is provided on the outer surface of the substrate layer. The infrared-controlled printing layer is made of ITO / ATO composite oxide. The functional coating layer includes a first aluminum plating layer and a first boron nitride layer arranged sequentially from the outside to the inside. The first boron nitride layer of the outer layer and the first boron nitride layer of the inner layer are compositely connected by an adhesive layer. The first aluminum plating layer and the first boron nitride layer are combined and arranged in a sequential plating manner.

2. The multi-band infrared stealth composite material according to claim 1, characterized in that, An intermediate layer is provided between the outer layer and the inner layer. The intermediate layer includes a PET substrate layer, a second aluminum plating layer and a second boron nitride layer arranged sequentially from top to bottom. The second aluminum plating layer and the second boron nitride layer are combined in a sequential plating manner.

3. The multi-band infrared stealth composite material according to claim 1, characterized in that, The conductive fiber is silver-plated nylon, copper-plated carbon fiber, or MXene-coated polyester.

4. The multi-band infrared stealth composite material according to claim 1, characterized in that, The substrate layer contains 80-95% aramid fiber and 5-20% conductive fiber, and the substrate layer density is 120-180 g / m². 2 .

5. The multi-band infrared stealth composite material according to claim 1, characterized in that, The sheet resistance of the infrared-controlled printing layer is <100Ω / Sq, and the emissivity range of the camouflage pattern is 0.3-0.

7.

6. The multi-band infrared stealth composite material according to claim 1, characterized in that, The thickness of the first aluminum layer in the functional coating is 30-80 nm, and the thickness of the first boron nitride layer in the functional coating is 0.5-2 μm.

7. The multi-band infrared stealth composite material according to claim 2, characterized in that, The thickness of the second aluminum plating layer in the intermediate layer is 30-80 nm, and the thickness of the second boron nitride layer in the intermediate layer is 0.5-2 μm.

8. The multi-band infrared stealth composite material according to claim 1, characterized in that, The adhesive layer is mainly composed of flame-retardant polyurethane adhesive, which contains boron nitride or graphene filler. The thermal conductivity of the flame-retardant polyurethane adhesive is >0.2W / m·K.

9. A method for preparing a multi-band infrared stealth composite material according to any one of claims 1-8, characterized in that, Includes the following steps: S1: Substrate layer preparation: 80-95% aramid fiber and 5-20% conductive fiber are blended to produce a surface density of 120-180 g / m². 2 The substrate layer; S2: Preparation of infrared-controlled printing layer: An infrared-controlled printing layer is made using ITO / ATO composite oxide, and a camouflage pattern is formed on the surface of the substrate layer obtained in step S1 by vacuum plating or rotary screen printing process. S3: Functional coating preparation: On the surface of the substrate layer after step S2, a first aluminum layer with a thickness of 30-80nm is first deposited by sequential plating, and then a first boron nitride layer with a thickness of 0.5-2μm is deposited to form a functional coating. S4: Outer and Inner Layer Production: Use the materials from step S3 as semi-finished products for the outer and inner layers, respectively, for later use; S5: Two-layer composite: The outer first boron nitride layer and the inner first boron nitride layer are bonded together by an adhesive layer to complete the preparation of multi-band infrared stealth composite material.

10. The method for preparing a multi-band infrared stealth composite material according to claim 9, characterized in that, Includes the following steps: S6: Intermediate layer preparation: After the outer and inner layers are prepared in step S4, an intermediate layer is set. On the PET substrate layer, a second aluminum layer with a thickness of 30-80nm and a second boron nitride layer with a thickness of 0.5-2μm are deposited in sequence to form the intermediate layer. S7: Three-layer composite: The outer first boron nitride layer is bonded to the middle PET substrate layer through an adhesive layer, and the inner first boron nitride layer is bonded to the middle second boron nitride layer through an adhesive layer, thus completing the preparation of the multi-band infrared stealth composite material.

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