An integrated infrared stealth heat dissipation, impact prevention integrated polyurea-based foam material and a preparation method and application thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-04-28
- Publication Date
- 2026-07-24
Smart Images
Figure CN122443047A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of stealth protection materials, specifically relating to a polyurea-based foam material that integrates infrared stealth heat dissipation and impact resistance, as well as its preparation method and application. Background Technology
[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.
[0003] Currently, the demand for protective materials in modern military equipment has completely moved beyond the limitations of single functions and is rapidly developing towards multi-functional integration. For military equipment, protective materials not only need to possess excellent infrared stealth performance to evade enemy infrared detection, but also need to have good comprehensive protective performance, such as impact resistance, to cope with various complex risks in the battlefield environment. However, from the perspective of existing technology, most polyurea-based materials on the market are mainly single-function, with obvious performance shortcomings: In terms of impact resistance, although ordinary polyurea-based materials can meet the impact protection requirements in conventional environments, their toughness and fracture resistance are significantly insufficient under extreme impact loads such as ammunition impact, equipment collision, and heavy object compression, making it difficult to effectively resist impact energy.
[0004] Furthermore, existing composite technologies based on polyurea materials and functional materials such as aerogels are still immature, with problems such as loose bonding at the composite interface and poor functional synergy. They are difficult to achieve synergistic optimization of multiple protective functions such as impact resistance and cannot meet the comprehensive protection needs of military equipment in complex battlefield environments. Summary of the Invention
[0005] To address the shortcomings of existing technologies, the present invention aims to provide a polyurea-based foam material integrating infrared stealth, heat dissipation, and impact resistance, along with its preparation method and applications. This material utilizes the low infrared emission characteristics of a micro / nano particle composite coating to achieve efficient infrared stealth functionality, and leverages the polyurea foam structure to achieve efficient impact resistance. This meets the stealth and protection requirements of vehicles, field base stations, and weaponry. The present invention develops a micro / nano particle-polyurea composite material with excellent impact resistance that can be synergistically integrated with infrared stealth functionality. This has significant practical and engineering application value for improving the overall protection level of military equipment and ensuring its battlefield survivability.
[0006] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, the present invention provides a polyurea-based foam material that integrates infrared stealth heat dissipation and impact resistance, which is an integrated multi-layer structure including an infrared stealth layer and an impact-resistant layer. The infrared stealth layer is a micro-nano particle composite coating structure, which is a combination of micro-nano particles and polymer materials. The impact-resistant layer is a polymer material with a foam structure.
[0007] Secondly, the present invention provides a method for preparing the above-mentioned integrated infrared stealth heat dissipation and impact resistance polyurea foam material, which includes the following steps: preparing slurry components for the infrared stealth layer and the impact resistance layer respectively, and then placing them in a mold to form the material.
[0008] Thirdly, the present invention provides an application of the above-mentioned integrated infrared stealth heat dissipation and impact resistance polyurea-based foam material in the military field.
[0009] One or more of the above technical solutions have the following advantages or beneficial effects: 1. This multilayer polyurea-based foam material exhibits high emissivity in non-atmospheric wavelengths at high temperatures, enabling efficient heat dissipation. It maintains high emissivity in the visible and near-infrared bands, while maintaining low emissivity in other bands. Compared to current materials, this invention achieves better heat management while also providing infrared stealth capabilities.
[0010] 2. To quantitatively characterize the protective effect of materials or structures against shock waves, dynamic parameters such as limiting specific energy absorption (SEA) and pressure attenuation rate are commonly used to assess the attenuation degree of the shock wave. SEA is an important parameter considering the impact of mass on the ballistic resistance performance of a system; it is the ratio of the energy absorbed by the tested material to its surface density. SEA reflects the ballistic resistance of a protective material under the same mass and is of great significance in fields such as impact protection.
[0011] 3. This invention achieves a tight interface bond and strong functional synergy by using the same material (polyurea foam) as the adhesive for both the impact-resistant layer and the infrared stealth layer, thus solving potential problems such as loose bonding and poor functional synergy in composite interfaces. Attached Figure Description
[0012] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.
[0013] Figure 1 This is a schematic diagram of the structure of a polyurea-based foam material that integrates stealth heat dissipation and impact resistance. Figure 2 This is a schematic diagram of the integrated stealth heat dissipation and impact resistance polyurea-based foam material prepared in Example 1; Figure 3This is a schematic diagram of the integrated stealth heat dissipation and impact resistance polyurea-based foam material prepared in Example 3; Figure 4 This is a schematic diagram of the integrated stealth heat dissipation and impact resistance polyurea-based foam material prepared in Example 4; Figure 5 This is a schematic diagram of the integrated stealth heat dissipation and impact resistance polyurea-based foam material prepared in Example 5; Figure 6 This is a schematic diagram of the integrated stealth heat dissipation and impact resistance polyurea-based foam material prepared in Example 6; Figure 7 This includes a finished product drawing and a dimensional diagram of the material. Detailed Implementation
[0014] The core objective of this invention, achieving integrated shock protection based on polyurea foam materials, lies in overcoming the technical bottlenecks of existing polyurea-based materials, such as limited functionality, poor shock resistance, and insufficient multi-functional synergy. It fully leverages the superior mechanical properties of polyurea materials to develop a polyurea-based foam material with shock-resistant properties that can be integrated with infrared stealth capabilities, thus meeting the stringent comprehensive protection requirements of military equipment. This invention significantly improves the shock resistance and damage resistance of polyurea-based foam materials: by optimizing the internal foam structure (parameters such as the size of the polyurea foam can be controlled by adjusting the heating temperature and water ratio according to its performance) and precisely regulating the material's mechanical parameters, the material possesses excellent toughness, fracture resistance, and impact energy absorption efficiency, effectively resisting extreme impact loads (including typical battlefield impact scenarios such as ammunition impact, equipment collision, and heavy object compression); simultaneously, it can rapidly absorb and dissipate impact energy, reducing the transmission of impact energy to the internal structure of military equipment, effectively protecting the integrity of internal precision components and electronic equipment, preventing equipment performance failure due to impact, and thus significantly improving the shock protection level of military equipment in complex battlefield environments.
[0015] The key to this invention lies in breaking the technical paradox of "mutual constraint between stealth and heat dissipation" that is prevalent in existing infrared stealth materials. It overcomes the performance defects of traditional infrared stealth materials in terms of emissivity control, multi-band adaptation, and environmental adaptability, and provides an infrared stealth technology solution that can balance infrared stealth and efficient heat dissipation, adapt to multi-band integrated detection environments, and meet the practical engineering application needs of military equipment. The first step is to achieve the following: 1. Achieving precise band-selective control of material infrared emissivity hinges on ensuring the material possesses stable low emissivity within the atmospheric infrared window band and efficient high-temperature, high-emissivity characteristics outside the atmospheric window band. Specifically, it maintains a high emissivity level in the visible and near-infrared bands, while strictly controlling the material's infrared emissivity to a low level in the short-wave, mid-wave infrared bands and the atmospheric window band. This effectively reduces the infrared radiation intensity on the object's surface, evading detection by enemy infrared detection equipment and achieving reliable and stable infrared stealth. Simultaneously, it ensures the material maintains high emissivity in the 5–8 μm non-atmospheric transmission window band, fully utilizing the radiative cooling effect to rapidly and efficiently dissipate heat accumulated inside military equipment, completely resolving the core technical contradiction of "low emissivity hindering heat dissipation." Ultimately, this achieves a synergistic unity between infrared stealth performance and efficient heat control performance, balancing stealth effectiveness with equipment operational stability.
[0016] 2. Optimize the structural design and fabrication process of materials to overcome the technical shortcomings of existing wavelength-selective stealth materials: simplify material structural design, reduce material fabrication difficulty and production costs; simultaneously, improve the environmental stability, durability, and large-scale fabrication capability of materials, ensuring that materials maintain stable infrared emissivity control performance under extreme battlefield environments such as temperature, humidity, and impact, thereby enhancing the environmental adaptability and practicality of materials. Specifically: optimize the structure, doping depth, particle diameter, etc., using code, and employ optimization algorithms such as genetic algorithms and machine learning.
[0017] 3. Laying the foundation for the synergistic integration of infrared stealth function with other protective functions such as impact resistance: While achieving excellent infrared stealth performance, ensuring that the material has good structural compatibility, it can be effectively combined with impact resistance technology based on polyurea materials, so that the infrared stealth function and other protective functions such as impact resistance can work together to meet the needs of military equipment for multifunctional integrated protective materials and further improve the comprehensive protection level of military equipment.
[0018] In one typical embodiment, the present invention provides a polyurea-based foam material that integrates infrared stealth heat dissipation and impact resistance, which is an integrated multi-layer structure including an infrared stealth layer and an impact-resistant layer. The infrared stealth layer is a micro-nano particle composite coating structure, which is a combination of micro-nano particles and polymer materials. The impact-resistant layer is a polymer material with a foam structure.
[0019] The impact-resistant layer alone does not provide stealth capabilities; its infrared emissivity remains above 0.92.
[0020] The FOM value is 1.1 to 1.5, specifically 1.1, 1.2, 1.3, 1.4, 1.45, 1.48, 1.5, etc.
[0021] Polyurea-based foam material integrating infrared stealth heat dissipation and impact resistance generates a high average emissivity in the 5-8μm heat dissipation band, with an average emissivity of 0.5~0.6, specifically 0.5, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, etc.
[0022] Meanwhile, its average emissivity in the atmospheric window is relatively low, ranging from 0.2 to 0.5 in the short-wave infrared (specifically 0.2, 0.23, 0.3, 0.4, 0.41, 0.42, 0.43, 0.45, 0.5, etc.); from 0.3 to 0.5 in the mid-wave infrared (specifically 0.3, 0.31, 0.32, 0.35, 0.4, 0.42, 0.45, 0.48, 0.5, etc.); and from 0.05 to 0.1 in the long-wave infrared (specifically 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, etc.).
[0023] The limiting specific energy absorption is 8~15 J·m 2 / kg, specifically 8J·m 2 / kg, 9J·m 2 / kg, 10J·m 2 / kg, 10.5J·m 2 / kg, 11J·m 2 / kg, 12J·m 2 / kg, 12.5J·m 2 / kg, 13J·m 2 / kg, 14J·m 2 / kg, 15J·m 2 / kg, etc.
[0024] In one or more embodiments, the polymer material in the micro / nano particle composite layer includes polymer materials such as polyurea and polyethylene, preferably polyurea.
[0025] In one or more embodiments, the micro / nanoparticles are granular, including sheet-like, spherical, and other shapes. The internal structure of the micro / nanoparticles may be a core-shell structure, etc.
[0026] The micro-nano particles are arranged in a uniformly dispersed manner, preferably in a parallel and densely packed arrangement of sheet-like particles.
[0027] Furthermore, the micro-nano particles are core-shell structured micro-nano particles. The outer shell material of the core-shell structure is CaMg(CO3)2 or Ge, with a radius of 0.5~1μm; the inner shell material of the core-shell structure is Ge or VO2, with a radius of 0.5~1μm; the core of the core-shell structure is VO2 or air, with a radius of 0.05~0.5μm.
[0028] Preferably, in the core-shell structure of the micro / nanoparticles, the outer shell material is Ge with a radius of 0.5~1μm, the inner shell material is VO2 with a radius of 0.5~1μm, and the core is air with a radius of 0.05~0.5μm. When using this core-shell material as the micro / nanoparticles, the thickness of the micro / nanoparticle composite layer is 20~30μm, specifically 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30μm, preferably 24~26μm, and most preferably 25μm. A suitable thickness range is needed to achieve both stealth and heat dissipation effects.
[0029] Preferably, in the core-shell structure of the micro / nano particles, the outer shell material is CaMg(CO3)2 with a radius of 0.5~1μm, preferably 0.8μm; the inner shell material is Ge with a radius of 0.5~1μm, preferably 0.64μm; and the core is VO2 with a radius of 0.05~0.5μm, preferably 0.05~0.1μm, more preferably 0.08μm. When using this core-shell material as the micro / nano particles, the thickness of the micro / nano particle composite layer is 1~10μm, specifically 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, etc., preferably 5~7μm, and most preferably 6μm. A suitable thickness range is needed to achieve both stealth and heat dissipation effects.
[0030] Furthermore, in the micro / nano particle composite layer, the volume fraction of the core-shell structure is 1-10%, specifically 1%, 2%, 3%, 4%, 5%, 6%, 7%, 7.5%, 8%, 9%, 10%, etc., preferably 5-10%. Neither too large nor too small a volume fraction of the core-shell structure provides infrared stealth. Too large a fraction results in a dense particle layer, while too small a fraction results in a porous polyurea structure.
[0031] In one or more embodiments, the impact-resistant layer material includes high molecular weight polymers such as polyurea and polyethylene, preferably polyurea. The polyurea is prepared by reacting isocyanate and amino compounds.
[0032] Optionally, the adhesives for the impact-resistant layer and the infrared stealth layer can be one or different types of polymer materials.
[0033] In one or more embodiments, the impact-resistant layer material is a polyurea modified with polyethylene, Kevlar fiber, or basalt (i.e., polyurea doped with polyethylene, Kevlar fiber, or basalt fiber), with a thickness of 1 to 10 mm, specifically 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc., preferably 5 to 10 mm, more preferably 6 mm; the fiber content is 0.1 to 1% (mass percentage based on the impact-resistant layer), preferably 0.3 to 0.5%, more preferably 0.4%.
[0034] Modified polyethylene, modified Kevlar fiber, and modified basalt will enhance the impact resistance of polyurea foam.
[0035] In a preferred embodiment, the integrated infrared stealth and impact-resistant polyurea-based foam material is an integrated multi-layer structure, comprising an infrared stealth layer and an impact-resistant layer. The infrared stealth layer is a micro-nano particle composite coating structure, wherein the micro-nano particle composite layer is a combination of core-shell micro-nano particles and a polymer material; the polymer material is PE or polyurea polymer material; and the impact-resistant layer is a polyurea material.
[0036] In a typical embodiment, the present invention provides a method for preparing the above-mentioned integrated infrared stealth heat dissipation and impact resistance polyurea-based foam material, comprising the following steps: Prepare the slurry components for the infrared stealth layer and the impact-resistant layer separately, and then place them in a mold to form the material.
[0037] This invention adopts an integrated preparation method for the infrared stealth layer and the impact-resistant layer, which has the effect of stronger adhesion. If the method of preparing them separately and then bonding them together is adopted, problems such as weak adhesion may occur.
[0038] In one or more embodiments, when the polymer material in the infrared stealth layer is polyurea, the preparation method of the infrared stealth layer slurry component includes: mixing and stirring an amino compound, water and micro / nano particles, allowing it to stand to remove bubbles, and then adding isocyanate and stirring to obtain the slurry component of the infrared stealth layer.
[0039] Furthermore, the preparation process of the slurry components for the infrared stealth layer is carried out under water bath heating conditions of 50~70℃. Temperature affects the reaction rate and the speed of bubble generation, thus affecting the overall structure.
[0040] The amino compound includes poly-1,4-butanediol bis(4-aminobenzoate). Before adding the amino compound, it must be preheated to 50-70°C. Then, the preheated amino compound, water, and micro / nano particles are mixed.
[0041] Furthermore, the mass ratio of isocyanate, amino compound and water is (2~5):(6~8):1.
[0042] Furthermore, the amino compound, water, and micro / nano particles are mixed and stirred for 10-60 seconds, preferably 20-40 seconds, at a rotation speed of 200-500 r / min, thereby improving the uniformity of the micro / nano particles in the matrix.
[0043] Furthermore, the settling time is 0.5 to 1.5 hours, which allows air bubbles generated by stirring to be eliminated.
[0044] Further, when isocyanate is added, stirring is required for 2 to 10 minutes, preferably 4 to 6 minutes, to ensure that all components are fully mixed.
[0045] In one or more embodiments, when the polymer material in the infrared stealth layer is PE, the preparation method of the infrared stealth layer slurry component includes: heating and melting PE, then stirring or ultrasonically vibrating micro-nano particles, and allowing it to stand to remove bubbles, thus obtaining the final product. The heating temperature can be 160~220℃. Mechanical stirring or ultrasonic vibration can be used, and the stirring time or ultrasonic vibration time is not specifically limited, but the goal is to achieve uniform dispersion of micro-nano particles in PE as much as possible. For example, the mechanical stirring time can be 1~60min, and the ultrasonic vibration time can be 30s~30min, etc.
[0046] In one or more embodiments, the preparation method of the slurry component of the impact-resistant layer includes: mixing and stirring an amino compound, water and fiber, allowing it to stand to remove bubbles, and then adding isocyanate and stirring to obtain the final product.
[0047] Furthermore, the process is carried out under water bath heating conditions of 50~70℃.
[0048] Furthermore, the mass ratio of isocyanate, amino compound and water is (2~5):(6~8):1.
[0049] Furthermore, the amino compound, water, and fiber are mixed and stirred for 1-10 minutes to improve the uniformity of fiber dispersion.
[0050] Furthermore, the settling time is 0.5 to 1.5 hours, which allows air bubbles generated by stirring to be eliminated.
[0051] Further, when isocyanate is added, stirring is required for 2 to 10 minutes, preferably 4 to 6 minutes, to ensure that all components are fully mixed.
[0052] In one or more embodiments, the slurry components of the impact-resistant layer are first added to the mold, followed by the slurry components of the infrared stealth layer, and the mold is left to stand at room temperature to allow for foaming and molding.
[0053] Preferred methods for preparing polyurea-based foam materials that integrate stealth, heat dissipation, and impact resistance include: First, the preparation of micro-nano particle composite coatings involves stirring a matrix of polymers such as polyethylene and polydimethylsiloxane with materials such as micro-nano particles, which can be done using methods such as ultrasonic stirring.
[0054] Next, taking polyurea-based foam as an example, the impact-resistant layer is prepared by stirring the matrix material (amino compound), distilled water, and other additives (such as fibers) in a water bath. The uniformly dispersed material is then allowed to stand to remove air bubbles generated during stirring. After the air bubbles are eliminated, the isocyanate component is added and stirring continues in a water bath. The mixture is then placed in a vacuum heating device to ensure the polyurea structure is formed. Once the formation is confirmed, the material is removed and cut using appropriate tools to complete the material fabrication.
[0055] In one typical embodiment, the present invention provides an application of the aforementioned integrated infrared stealth heat dissipation and impact resistance polyurea-based foam material in the military field. For example, as military equipment, it is suitable for conditions such as ammunition impact, equipment collision, and heavy object compression.
[0056] This invention provides a polyurea-based foam material that integrates stealth and impact resistance. (Reference) Figure 1 The polyurea-based foam material provided by this invention integrates stealth and impact resistance, from top to bottom (relative to...) Figure 1 (In other words) it includes a micro-nano particle composite layer 1 and an impact-resistant layer 2.
[0057] This invention provides a polyurea-based foam material that integrates stealth and impact resistance, exhibiting good specific spectral emissivity. The spectral reflectance and spectral transmittance of this material can be obtained using electromagnetic field calculations. Based on Kirchhoff's law, the directional spectral emissivity of an opaque surface equals its directional spectral absorbance.
[0058] The emissivity of this material can be obtained based on its spectral directional reflectance and transmittance.
[0059] in, S solar ( λ (This refers to the heat flux of solar spectral radiation.) E bλ This represents the blackbody spectral radiative power.
[0060] The Field of Analysis (FOM) is used to evaluate the performance indicators of infrared stealth and radiative thermal management in order to find the optimal parameters for the material. Specifically, FOM equals the sum of the amplitude of infrared emissivity modulation in the non-atmospheric window band and the differences between the emissivity of other bands and the target emissivity. FOM=(1- )+
[0061] in, ε normal denoted as Total Normal Emissivity (FOM). "non" and "other" represent the non-atmospheric window band and other spectral bands, respectively. By finding the minimum value of FOM, the parameters of the micro / nano particle composite coating structure can be optionally obtained.
[0062] The limiting specific energy absorption of this invention is evaluated using the pressure decay rate, and the calculation method is as follows:
[0063]
[0064] Among them, among them, The surface density of the material. For the ballistic limit energy absorption of the structure, For the mass of the projectile, bl This represents the ballistic limit.
[0065] Core-shell multilayer spherical particles can be prepared by a layer-by-layer coating approach: first, dense core microspheres are prepared by polymerization, sol-gel or powder molding methods, and then single-layer shells of different materials are deposited sequentially on the surface of the core microspheres using electrostatic self-assembly, sol coating, in-situ deposition, emulsion composite polymerization or fluidized bed coating processes. After curing, drying or high-temperature heat treatment to stabilize the interface structure, the multilayer coating and post-processing process is repeated to finally obtain multilayer composite spherical particles with regular structure, controllable layer thickness and gradient distribution of components.
[0066] In this invention, unless otherwise specified, all other test materials and instruments are conventional test materials in the field and can be purchased through commercial channels.
[0067] In the following embodiments, the core-shell structured micro-nanoparticles may be commercially available or may be those disclosed in the literature (Bowei Xie, Jian Zhan, Mu Du, Composite coating with engineered micro-particles for multiband infrared stealth and efficient radiative heatdissipation, applied optics 64, 8011 (2025)).
[0068] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.
[0069] Example 1 A polyurea-based foam material integrating stealth heat dissipation and impact resistance includes a micro-nano particle composite layer 1 and an impact-resistant layer 2.
[0070] The micro / nano particle composite layer 1 consists of core-shell structured micro / nano particles combined with PE. The outer shell material is CaMg(CO3)2 with a radius of 0.8 μm, the inner shell material is Ge with a radius of 0.64 μm, and the core is VO2 with a radius of 0.08 μm. The volume fraction of the core-shell structure is 10%. The thickness of the micro / nano particle composite layer is 6 μm.
[0071] The impact-resistant layer 2 is made of basalt-modified polyurea with a thickness of 6 mm and a fiber content of 1.2% (by mass).
[0072] The preparation method of the polyurea-based foam material integrating stealth heat dissipation and impact resistance includes the following steps: The preparation method of the polyurea-based foam material that integrates stealth heat dissipation and impact resistance: The preparation process of material C includes: heating and melting PE at 160~220℃, then adding micro-nano particles, and mixing by stirring or ultrasonic vibration to improve the uniformity of micro-nano particles in the matrix. The uniformly dispersed material is then allowed to stand for 60 minutes to remove air bubbles generated by stirring, thus obtaining material C.
[0073] Simultaneously, component B (amino compound) was preheated in an electric oven at 60°C. Then, a certain amount of fiber material and distilled water were added, and the mixture was stirred at high speed (fixed 360 r / min) for 1 minute to improve the uniformity of the fibers in the matrix. The mixture was then kept at 60°C for another 5 minutes, and the uniformly dispersed material was allowed to stand for 60 minutes to remove air bubbles generated during stirring. After the air bubbles were completely eliminated, component A (isocyanate) was added, and the mixture was stirred for 5 minutes to obtain material D. In material D, the ratio of component A: component B: distilled water was 3:7:1 by mass.
[0074] Finally, at room temperature, first place material D into the mold, then add material C into the mold. After standing at room temperature until foaming is complete, polyurea-based foam material is obtained. After confirming the molding, remove the material and cut it with appropriate tools to complete the material production.
[0075] refer to Figure 2 The FOM value is 1.1364. The integrated stealth and impact-resistant polyurea-based foam material exhibits a high average emissivity of 0.5091 in the 5-8 μm heat dissipation band. Simultaneously, it displays relatively low average emissivity in the atmospheric window, at 0.2326 (shortwave infrared), 0.3208 (midwave infrared), and a significantly higher 0.0915 (longwave infrared). Its limiting specific energy absorption is 10.54 J·m. 2 / kg.
[0076] Example 2 A polyurea-based foam material integrating stealth heat dissipation and impact resistance includes a micro-nano particle composite layer 1 and an impact-resistant layer 2.
[0077] The micro / nano particle composite layer 1 is a combination of core-shell structured micro / nano particles and polyurea. The outer shell material is CaMg(CO3)2 with a radius of 0.8 μm, the inner shell material is Ge with a radius of 0.64 μm, and the core is VO2 with a radius of 0.08 μm. The volume fraction of the core-shell structure is 10%. The thickness of the micro / nano particle composite layer is 6 μm.
[0078] The impact-resistant layer 2 is made of basalt-modified polyurea with a thickness of 6 mm and a fiber content of 1.2% (by mass).
[0079] The preparation method of the polyurea-based foam material integrating stealth heat dissipation and impact resistance includes the following steps: First, isocyanate (referred to as component A) and amino compound (referred to as component B) are mixed. Component B is preheated in a 60°C electric oven. Component B is then added to distilled water and micro / nano particles, and stirred at high speed (fixed 360 rpm) for 30 seconds to improve the uniformity of the micro / nano particles in the matrix. The uniformly dispersed material is allowed to stand for 60 minutes to remove air bubbles generated by stirring. After the air bubbles are completely eliminated, component A is added, and stirring continues for 5 minutes in a 60°C water bath to obtain material C. In material C, the ratio of component A: component B: distilled water is 3:7:1, by mass.
[0080] Meanwhile, component B was preheated in an electric oven at 60℃, then a certain amount of fiber material and distilled water were added and mixed at high speed (fixed 360 r / min) for 1 minute to improve the uniformity of the fibers in the matrix. The mixture was then kept at 60℃ for another 5 minutes, and the evenly dispersed material was allowed to stand for 60 minutes to remove air bubbles generated during mixing. After the air bubbles were completely eliminated, component A was added and stirred for 5 minutes to obtain material D. In material D, the ratio of component A: component B: distilled water was 3:7:1 by mass.
[0081] Finally, at room temperature, first place material D into the mold, then add material C into the mold. After standing at room temperature until foaming is complete, polyurea-based foam material is obtained. After confirming the molding, remove the material and cut it with appropriate tools to complete the material production.
[0082] In this embodiment, the limiting specific energy absorption of the polyurea-based foam material integrating stealth heat dissipation and impact resistance is 11.05 J·m. 2 / kg.
[0083] Example 3 A polyurea-based foam material integrating stealth heat dissipation and impact resistance, comprising a micro-nano particle composite layer 1 and an impact-resistant layer 2 from top to bottom.
[0084] The micro / nano particle composite layer 1 consists of a core-shell structure bonded to a PE adhesive. The outer shell material is CaMg(CO3)2 with a radius of 0.8 μm, the inner shell material is Ge with a radius of 0.64 μm, and the core is VO2 with a radius of 0.08 μm. The volume fraction of the core-shell structure is 10%, and the thickness of the micro / nano particle composite layer is 6 μm.
[0085] The impact-resistant layer 2 is made of polyurea modified with Kevlar fiber, with a thickness of 6 mm and a fiber content of 0.4%.
[0086] The preparation method is the same as in Example 1.
[0087] refer to Figure 3The FOM value is 1.4893. Its limiting specific energy absorption is 12.38 J·m. 2 / kg.
[0088] Example 4 A polyurea-based foam material integrating stealth heat dissipation and impact resistance, comprising a micro-nano particle composite layer 1 and an impact-resistant layer 2 from top to bottom.
[0089] The micro / nano particle composite layer 1 consists of a core-shell structure bonded to a PE adhesive. The outer shell material is CaMg(CO3)2 with a radius of 0.8 μm, the inner shell material is Ge with a radius of 0.64 μm, and the core is VO2 with a radius of 0.08 μm. The volume fraction of the core-shell structure is 10%, and the thickness of the micro / nano particle composite layer is 6 μm.
[0090] The impact-resistant layer 2 is made of polyurea modified with Kevlar fiber, with a thickness of 6 mm and a fiber content of 0.4%.
[0091] The preparation method is the same as in Example 1.
[0092] refer to Figure 4 The FOM value is 1.4893. Its limiting specific energy absorption is 12.38 J·m. 2 / kg.
[0093] Example 5 A polyurea-based foam material integrating stealth heat dissipation and impact resistance, comprising a micro-nano particle composite layer 1 and an impact-resistant layer 2 from top to bottom.
[0094] The micro / nano particle composite layer 1 consists of a core-shell structure bonded to a PE adhesive. The outer shell material is CaMg(CO3)2 with a radius of 0.8 μm, the inner shell material is Ge with a radius of 0.64 μm, and the core is VO2 with a radius of 0.08 μm. The volume fraction of the core-shell structure is 10%, and the thickness of the micro / nano particle composite layer is 6 μm.
[0095] The impact-resistant layer 2 is made of polyethylene-modified polyurea, with a thickness of 6 mm and a fiber content of 0.4%.
[0096] The preparation method is the same as in Example 1.
[0097] refer to Figure 5 The FOM value is 1.4893. Its limiting specific energy absorption is 10.06 J·m. 2 / kg.
[0098] Example 6 A polyurea-based foam material integrating stealth heat dissipation and impact resistance, comprising a micro-nano particle composite layer 1 and an impact-resistant layer 2 from top to bottom.
[0099] The micro / nano particle composite layer 1 consists of a core-shell structure bonded to a PE adhesive. The outer shell material is CaMg(CO3)2 with a radius of 0.8 μm, the inner shell material is Ge with a radius of 0.64 μm, and the core is VO2 with a radius of 0.08 μm. The volume fraction of the core-shell structure is 10%, and the thickness of the micro / nano particle composite layer is 6 μm.
[0100] The impact-resistant layer 2 is made of polyethylene-modified polyurea, with a thickness of 6 mm and a fiber content of 1.2%.
[0101] The preparation method is the same as in Example 1.
[0102] refer to Figure 6 The FOM value is 1.4893. Its limiting specific energy absorption is 8.33 J·m. 2 / kg.
[0103] like Figure 7 As shown, the dimensions of the materials used in the experiment were all Φ90×30mm.
[0104] Example 7 A polyurea-based foam material integrating stealth heat dissipation and impact resistance comprises, from top to bottom, a micro / nano particle composite layer 1 and an impact-resistant layer 2. Unlike Example 2, the core-shell structure of the micro / nano particle composite layer 1 is different, specifically: The micro / nano particle composite layer 1 is a combination of core-shell structured micro / nano particles and polyurea. The outer shell material is Ge 1μm, the inner shell material is VO2 0.85μm, and the core is air 0.5μm. The volume fraction of the core-shell structure is 7.5%. The thickness of the micro / nano particle composite layer is 25μm.
[0105] The 5-8 μm heat dissipation band produces a high average emissivity of 0.5458. However, it exhibits lower average emissivity in the atmospheric window, at 0.4238 (shortwave infrared), 0.4872 (midwave infrared), and a significantly higher 0.0826 (longwave infrared). Its limiting specific energy absorption is 10.54 J·m⁻¹. 2 / kg.
[0106] Building upon Example 7, the influence of the thickness of the micro / nano particle composite layer was further explored. Specifically, micro / nano particle composite layer 1 is a combination of core-shell structured micro / nano particles and polyurea. The outer shell material of the core-shell structure is Ge 1μm, the inner shell material is VO2 0.85μm, and the core is air 0.5μm. The volume fraction of the core-shell structure is 7.5%. The results for different thicknesses are shown in Table 1 below. Therefore, when the above core-shell structure is applied to the micro / nano particle composite layer, the thickness of the micro / nano particle composite layer must be controlled within a suitable range (20~30μm) to achieve both good stealth and heat dissipation effects.
[0107] Table 1
[0108] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A polyurea-based foam material integrating infrared stealth heat dissipation and impact resistance, characterized in that, It has an integrated multi-layer structure, including an infrared stealth heat dissipation layer and an impact-resistant layer; The infrared stealth heat dissipation layer is a micro-nano particle composite coating structure, which is a combination of micro-nano particles and polymer materials. The impact-resistant layer is a polymer material with a foam structure.
2. The polyurea-based foam material according to claim 1, characterized in that, In the micro / nano particle composite layer, the polymer material includes polyurea or PE; Preferably, the impact-resistant layer material includes at least one of polyurea and polyethylene, with polyurea being the most preferred; Preferably, the thickness of the impact-resistant material is 1~10mm.
3. The polyurea-based foam material according to claim 2, characterized in that, The micro-nano particles are core-shell structured micro-nano particles; the outer shell material of the core-shell structure is CaMg(CO3)2 or Ge, with a radius of 0.5~1μm; the inner shell material of the core-shell structure is Ge or VO2, with a radius of 0.5~1μm; the core of the core-shell structure is VO2 or air, with a radius of 0.05~0.5μm.
4. The polyurea-based foam material according to claim 3, characterized in that, The outer shell material of the core-shell structure of the micro-nano particles is Ge with a radius of 0.5~1μm, the inner shell material is VO2 with a radius of 0.5~1μm, and the core is air with a radius of 0.05~0.5μm; the thickness of the micro-nano particle composite layer is 20~30μm. Alternatively, the outer shell material of the core-shell structure is CaMg(CO3)2 with a radius of 0.5~1μm; the inner shell material is Ge with a radius of 0.5~1μm; the core is VO2 with a radius of 0.05~0.5μm; and the thickness of the micro-nano particle composite layer is 1~10μm. Preferably, the volume fraction of the core-shell structure in the micro / nano particle composite layer is 1-10%.
5. The polyurea-based foam material according to claim 1, characterized in that, The impact-resistant material also contains fibers, with a fiber content of 0.1% to 1%. Preferably, the fiber is one or more of polyethylene, Kevlar fiber, and modified basalt.
6. A method for preparing a polyurea-based foam material integrating infrared stealth heat dissipation and impact resistance as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Prepare the slurry components for the infrared stealth layer and the impact-resistant layer separately, and then place them in a mold to form the material.
7. The preparation method according to claim 6, characterized in that, When the polymer material in the infrared stealth heat dissipation layer is polyurea, the preparation method of the infrared stealth layer slurry component includes: mixing and stirring an amino compound, water and micro-nano particles, letting it stand to remove bubbles, and then adding isocyanate and stirring to obtain the slurry component of the infrared stealth layer. Preferably, the preparation process is carried out under water bath heating conditions of 50~70℃; Preferably, the mass ratio of isocyanate, amino compound and water is (2~5):(6~8):1; Preferably, the amino compound, water, and micro / nano particles are mixed and stirred for 10-60 seconds; Preferably, the settling time is 0.5~1.5h; Preferably, after adding isocyanate, stirring for 2 to 10 minutes is required; Alternatively, when the polymer material in the infrared stealth heat dissipation layer is PE, the preparation method of the infrared stealth layer slurry component includes: heating and melting PE, then adding micro-nano particles for stirring or ultrasonic vibration, and allowing it to stand to remove bubbles, thus obtaining the final product.
8. The preparation method according to claim 6, characterized in that, The preparation method of the slurry components of the impact-resistant layer includes: mixing and stirring an amino compound, water and fiber, allowing it to stand to remove bubbles, and then adding isocyanate and stirring to obtain the final product; Preferably, the process is carried out under water bath heating conditions of 50~70℃; Preferably, the mass ratio of isocyanate, amino compound and water is (2~5):(6~8):1; Preferably, the amino compound, water, and fiber are mixed and stirred for 1 to 10 minutes; Preferably, the settling time is 0.5~1.5h; Preferably, isocyanate is added and stirring is required for 2 to 10 minutes.
9. The preparation method according to claim 6, characterized in that, In the mold, the slurry components of the impact-resistant layer are added first, followed by the slurry components of the infrared stealth layer. The mold is then left to stand at room temperature to allow for foaming and molding.
10. The application of a polyurea-based foam material integrating infrared stealth, heat dissipation, and impact resistance as described in any one of claims 1 to 5, or a polyurea-based foam material integrating infrared stealth and impact resistance prepared by the preparation method described in any one of claims 6 to 9, in the military field.