Broadband wave-absorbing patch with extreme environment tolerance as well as preparation method and application of broadband wave-absorbing patch
By designing a multi-layer structure and using chemical bonding bridging, the extreme environmental tolerance and broadband absorption performance of the absorbing patch were improved. This solved the problems of high temperature resistance, corrosion and delamination warping in the existing technology, and achieved stable operation in extreme environments and excellent electromagnetic stealth performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-17
- Publication Date
- 2026-04-07
AI Technical Summary
Existing absorbing patches have poor tolerance to extreme environments, especially lack of high-temperature stability, easy corrosion, delamination and warping, and insufficient broadband absorption performance and surface protection compatibility.
A broadband absorbing patch is designed, comprising a first corrosion-resistant layer, an absorbing layer, a second corrosion-resistant layer, and an adhesive layer arranged sequentially from top to bottom. A special fluorosilicone is used as the substrate, and the interlayer bonding force is improved by chemical bonding bridging method. The surface of the absorbing layer is treated with a siloxane-containing primer.
It achieves long-term stable operation in extreme environments, has ultra-long salt spray resistance and damp heat resistance, and improves the patch's broadband absorption performance and surface protection strength, thus resolving the contradiction between high temperature resistance and solvent resistance.
Smart Images
Figure CN121812955A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of stealth material preparation technology, and relates to a broadband absorbing patch with extreme environmental tolerance, its preparation method and application. Background Technology
[0002] As high-tech equipment such as aerospace, radar detection, high-temperature electronics, and marine platforms develop towards higher power density and higher integration, the electromagnetic interference and compatibility issues they face are becoming increasingly severe. As a core means of suppressing electromagnetic radiation, improving signal integrity, and achieving target stealth, the performance of absorbing materials directly affects the electromagnetic compatibility and survivability of equipment. Therefore, there is an urgent need to design an absorbing material that can efficiently attenuate electromagnetic waves over a wide frequency band and can operate stably for a long time in extreme and complex environments such as high temperature, thermal shock, salt spray, humid heat, and organic solvent corrosion, especially in a patch form that is easy to install and maintain.
[0003] Currently, flexible absorbing patches are mainly made of rubber (such as silicone rubber, fluorosilicone rubber, and polyurethane) as the matrix and filled with magnetic absorbers (such as carbonyl iron powder). However, existing technologies still have the following defects and contradictions in achieving synergistic optimization of environmental tolerance and broadband absorption performance: 1. Poor tolerance to extreme environments: Firstly, there is insufficient high-temperature stability. Mainstream rubber matrices, such as ordinary silicone rubber, fluorosilicone, and polyurethane rubber, generally have long-term operating temperatures below 200℃. Secondly, carbonyl iron powder, used as an absorbent, easily corrodes and rusts in high-humidity and high-salt-spray environments. Simultaneously, the high-temperature resistance and oil solvent resistance of absorbing patches present a trade-off. Fluorosilicone-based absorbing patches typically withstand temperatures up to 220℃, but swelling occurs after immersion in oil solvents such as aviation fuel and hydraulic oil. Furthermore, while ordinary fluorosilicone exhibits excellent oil solvent resistance, its high-temperature resistance is inferior to that of silicone rubber. Therefore, achieving both high-temperature resistance and solvent resistance in absorbing patches is a significant challenge that needs to be overcome.
[0004] 2. While broadband absorption performance can be achieved through multilayer structural design, the thermal shrinkage rates between layers differ, leading to delamination or warping of the patch under temperature shock. To meet the requirements for oil solvent resistance, fluorosilicone is typically used as the rubber matrix. However, fluorosilicone-based patches have low surface energy, resulting in poor interfacial compatibility between the corrosion-resistant coating and the patch surface. This leads to low adhesion between the corrosion-resistant coating and the patch, causing coating cracking and peeling.
[0005] In view of this, the present invention is hereby proposed. Summary of the Invention
[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a broadband absorbing patch with extreme environmental tolerance, its preparation method and application, so as to solve the comprehensive problem in the prior art that it is impossible to simultaneously achieve broadband high-efficiency absorption, long-term tolerance to extreme environments (high temperature, corrosion, solvents), high-temperature stability of multilayer structure and effective surface protection.
[0007] To achieve the above objectives, the present invention provides the following technical solution: On the one hand, the present invention provides a broadband absorbing patch with extreme environmental resistance, comprising: a first corrosion-resistant layer, a microwave absorbing layer, a second corrosion-resistant layer and an adhesive layer arranged sequentially from top to bottom, wherein the composition and amount of the second corrosion-resistant layer are the same as those of the first corrosion-resistant layer; The first corrosion-resistant layer comprises, by weight, the following components: 50 to 65 parts of film-forming substance, 1 to 5 parts of crosslinking agent, 0.1 to 1 part of catalyst, 5 to 10 parts of reinforcing agent, 1 to 3 parts of adhesion promoter, 5 to 10 parts of corrosion-resistant filler, and 10 to 40 parts of solvent; The microwave absorbing layer comprises the following components by weight: 20-23 parts of rubber substrate, 55-65 parts of first absorber, 10-20 parts of second absorber, 1-2 parts of silane coupling agent, and 1-3 parts of vulcanizing agent.
[0008] It should be noted that, in principle, the weight percentages of each component in the first corrosion-resistant layer should be within their respective required ranges; for example, the weight percentages of the film-forming substance can be 50 parts, 52 parts, 55 parts, 56 parts, 58 parts, 60 parts, 62 parts, 63 parts, 65 parts, etc., and will not be listed here; the weight percentages of the crosslinking agent can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, etc., and will not be listed here; the weight percentages of the catalyst can be 0.1 parts, 0.2 parts, 0.3 parts, 0.5 parts, 0.8 parts, 1 part, etc., and will not be listed here. The following are not listed individually: the mass fractions of reinforcing agents can be 5, 6, 7, 8, 9, 10, etc., and will not be listed individually here; the mass fractions of adhesion promoters can be 1, 1.5, 2, 2.5, 3, etc., and will not be listed individually here; the mass fractions of corrosion-resistant fillers can be 5, 6, 7, 8, 9, 10, etc., and will not be listed individually here; the mass fractions of solvents can be 10, 15, 20, 25, 30, 35, 40, etc., and will not be listed individually here.
[0009] It should be noted that, in principle, the weight percentages of each component in the absorbing layer should be within their respective required ranges. For example, the weight percentages of the rubber substrate can be 20, 21, 22, 23, etc., and will not be listed here; the weight percentages of the first absorbent can be 55, 56, 58, 60, 62, 65, etc., and will not be listed here; the weight percentages of the second absorbent can be 10, 12, 14, 15, 16, 18, 20, etc., and will not be listed here; the weight percentages of the silane coupling agent can be 1, 1.2, 1.4, 1.6, 1.8, 2, etc., and will not be listed here; the weight percentages of the vulcanizing agent can be 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3, etc., and will not be listed here.
[0010] Specifically, the thickness of the first corrosion-resistant layer is 15μm~25μm; the thickness of the microwave-absorbing layer is 0.5mm~0.55mm; the thickness of the second corrosion-resistant layer is 15μm~25μm; and the thickness of the adhesive backing layer is 60μm~70μm.
[0011] Further, the film-forming substance includes any one of vinyl fluorosilicone oil, side-chain vinyl fluorosilicone oil, and high-vinyl fluorosilicone oil; the crosslinking agent includes any one of hydrogen-containing silicone oil and hydrogen-containing fluorosilicone oil; the catalyst is a platinum catalyst; the reinforcing agent is fumed silica; the adhesion promoter includes any one of epoxy silane and bisamino silane; the corrosion-resistant filler includes any one of calcium fluoride and nano boron nitride; and the solvent includes any one of xylene and butyl acetate.
[0012] Specifically, the rubber substrate is a special fluorosilicone (model G413, manufactured by Northwest Rubber & Plastics Research and Design Institute Co., Ltd.); the first absorbent is flake carbonyl iron powder F01; the second absorbent includes either flake carbonyl iron powder F02 or iron-silicon-chromium alloy powder; the silane coupling agent is vinyltriethoxysilane; and the vulcanizing agent is 2,5-dimethyl-2,5-dihexane.
[0013] Furthermore, the particle size of the flake carbonyl iron powder F02 is 5-8 μm larger than that of the flake carbonyl iron powder F01, and the particle sizes of the two are on the same order of magnitude.
[0014] On the other hand, the present invention also provides a method for preparing a broadband absorbing patch with extreme environmental tolerance as described in part or all of the above, comprising the following steps: Step 1: Prepare the mixture for the corrosion-resistant layer and the mixture for the microwave absorbing layer respectively; Step 2: Mix the microwave absorbing layer with the mixture, vulcanizing agent and rubber substrate evenly, and mold the evenly mixed mixture. Then, perform a two-stage vulcanization on the molded sheet in a drying equipment to obtain the microwave absorbing layer. Step 3: First, pre-treat the surface of the absorbing layer to activate it; then, spray the corrosion-resistant layer with a mixture onto the upper and lower surfaces of the absorbing layer, and then place it in a drying equipment for curing. After curing, the preparation of the "first corrosion-resistant layer - absorbing layer - second corrosion-resistant layer" layer structure is completed. Step 4: Adhesive backing layer is attached to the surface of the second corrosion-resistant layer and left to stand at room temperature for 6-8 hours to complete the preparation of a broadband absorbing patch with extreme environmental resistance.
[0015] Specifically, in step 1, the mixture for the corrosion-resistant layer is prepared first, followed by the mixture for the microwave-absorbing layer; or, the mixture for the microwave-absorbing layer is prepared first, followed by the mixture for the corrosion-resistant layer. 1) The specific process for preparing the mixture for the corrosion-resistant layer is as follows: The film-forming substance, reinforcing agent, adhesion promoter, corrosion-resistant filler and solvent are added to the mixing container in the required weight proportions and mixed and stirred to obtain mixture A; Add the corresponding weight parts of crosslinking agent and catalyst to the mixture A and disperse them to obtain the corrosion-resistant layer mixture B; 2) Prepare the microwave absorbing layer mixture according to the required weight parts. The microwave absorbing layer mixture includes mixture C and mixture D. The specific preparation process is as follows: After the first absorbent and half of the silane coupling agent are mixed evenly and dried, mixture C is obtained; After the second absorbent and the remaining silane coupling agent are mixed evenly and dried, mixture D is obtained.
[0016] Specifically, the mixing speed is 900~1200 r / min, and the mixing time is 30~40 min; the dispersion speed is 400~600 r / min, and the dispersion time is 5~10 min; the drying temperature is 80~100℃, and the drying time is 60~90 min; the molding temperature is 160~170℃, and the time is 8~15 min; the two-stage vulcanization temperature is 150~160℃, and the time is 180~240 min; the curing temperature is 80~100℃, and the curing time is 180~240 min.
[0017] Specifically, in step 3, the surface of the absorbing layer is pretreated, including: First, wipe the surface of the absorbing layer with alcohol to remove surface impurities or oil stains, and then wipe the surface of the absorbing layer with a siloxane-containing primer to achieve surface activation.
[0018] Furthermore, the present invention also provides the application of broadband absorbing patches as described in part or all of the above, or broadband absorbing patches prepared by the methods described in part or all of the above, in extreme service environments.
[0019] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: 1) The broadband absorbing patch structure designed in this invention includes a first corrosion-resistant layer, a microwave-absorbing layer, a second corrosion-resistant layer and an adhesive layer arranged sequentially from top to bottom. The layer structure design improves the patch's resistance to extreme environments, especially giving the patch ultra-long salt spray resistance and damp heat resistance. 2) The rubber substrate in the absorbing layer of this invention is a special fluorosilicone. Compared with ordinary fluorosilicone, it not only meets the requirements for resistance to oil solvents, but also has high temperature resistance, thus solving the problem that ordinary fluorosilicone is resistant to oil but not to high temperatures. 3) This invention employs a chemical bonding bridging method to improve the adhesion between the corrosion-resistant layer and the microwave-absorbing layer. After treating the surface of the microwave-absorbing layer with a siloxane-containing primer, the fluorosilicone surface is activated. The isopropanol / alkane solvent in the primer swells the fluorosilicone surface, exposing the inert methyl groups (-CH3). These groups hydrolyze under ambient humidity, simultaneously generating active silanol groups (Si-OH), increasing the density of bonding sites. Simultaneously, the silane coupling agent in the primer acts as a bridge, forming a covalent bond network of fluorosilicone-O-Si-R-NH-infrared layer, resulting in a strong adhesion between the corrosion-resistant layer and the microwave-absorbing layer. 4) The patch in this invention has broadband absorption performance at an ultra-thin thickness. By compounding absorbers with different morphologies, different loss mechanisms and different particle sizes, the electromagnetic parameters are adjusted and the impedance matching inside the patch is optimized to achieve broadband absorption performance. Attached Figure Description
[0020] The accompanying drawings are incorporated in and form part of this specification, and together with the description serve to explain the principles of the invention.
[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 A schematic diagram of a broadband absorbing patch with extreme environmental tolerance provided by the present invention; Figure 2 A flowchart illustrating a method for fabricating a broadband absorbing patch with extreme environmental tolerance, provided by this invention. Figure 3 The radar reflectivity curve of a broadband absorbing patch with extreme environmental tolerance prepared in Embodiment 1 of the present invention; Figure 4 The radar reflectivity curve of a broadband absorbing patch with extreme environmental tolerance prepared in Embodiment 2 of the present invention; Figure 5 The radar reflectivity curve of a broadband absorbing patch with extreme environmental tolerance prepared in Example 3 of the present invention is shown.
[0023] The layers are: 1. First corrosion-resistant layer; 2. Wave-absorbing layer; 3. Second corrosion-resistant layer; 4. Adhesive backing layer. Detailed Implementation
[0024] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples consistent with some aspects of the invention as detailed in the appended claims.
[0025] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.
[0026] First, the broadband absorbing patches of Examples 1-3 and the absorbing patches of Comparative Examples 1-2 were prepared using the components and amounts of each layer structure in Table 1 below.
[0027] Table 1 Example 1 See Figure 1 This embodiment provides a broadband absorbing patch with extreme environmental resistance, comprising, from top to bottom, a first corrosion-resistant layer 1, an absorbing layer 2, a second corrosion-resistant layer 3, and an adhesive layer 4. The composition and amount of the second corrosion-resistant layer are the same as those of the first corrosion-resistant layer. The first corrosion-resistant layer 1 comprises, by weight, the following components: 50 parts vinyl fluorosilicone oil, 2 parts hydrofluorosilicone oil, 0.3 parts platinum catalyst, 5 parts fumed silica, 1 part epoxy silane, 5 parts calcium fluoride, and 36.7 parts xylene. The microwave absorbing layer 2, by weight, comprises the following components: 23 parts of special fluorosilicone (model G413, manufactured by Northwest Rubber & Plastics Research and Design Institute Co., Ltd., with a temperature resistance up to 300℃), 65 parts of flake carbonyl iron powder F01, 10 parts of flake carbonyl iron powder F02, 1 part of vinyltriethoxysilane, and 1 part of 2,5-dimethyl-2,5-dihexane; The adhesive backing layer 4 uses a common double-sided adhesive high-temperature resistant tape, preferably 3M-300LSE adhesive.
[0028] Furthermore, this embodiment also provides a method for preparing the aforementioned broadband absorbing patch with extreme environmental tolerance, specifically including the following steps: Step 1: Prepare the mixture for the corrosion-resistant layer and the mixture for the microwave-absorbing layer separately; specifically, 1) The specific process for preparing the mixture for the corrosion-resistant layer is as follows: Vinyl fluorosilicone oil, fumed silica, epoxy silane, calcium fluoride and xylene were added to a mixing container in sequence and mixed using a stirring mill dispersion machine at a speed of 900 r / min for 40 min to obtain mixture A. Before spraying, add hydrofluoric silicone oil and platinum catalyst to mixture A, and disperse it using a stirring mill dispersion machine at a speed of 400 r / min for 10 min to obtain mixture B; 2) Prepare the absorbing layer mixture according to the required parts by weight: The flake carbonyl iron powder F01 and half of vinyltriethoxysilane (0.5 parts) were mixed evenly and placed in an oven. The drying temperature was 80℃ and the drying time was 90 min to obtain mixture C. The flake carbonyl iron powder F02 and the remaining vinyltriethoxysilane (0.5 parts) were mixed evenly and placed in an oven. The drying temperature was 80°C and the drying time was 90 min to obtain mixture D. Step 2: Mix mixture C, mixture D, 2,5-dimethyl-2,5-dihexane, and special fluorosilicone evenly to obtain mixture E; then pass mixture E through a thin pass 4 times, form a triangular package 5 times, and roll it 2 times in sequence. Then, use an open mill to produce sheets, use a calender to control the thickness, and place them into the mold of a flat vulcanizing machine. At 160°C, mold and vulcanize for 15 minutes. Then, place the molded sheet in an oven and perform a second-stage vulcanization at 150°C for 240 minutes to obtain microwave absorbing layer 2. Step 3: First, wipe the surface of the microwave absorbing layer obtained in Step 2 with alcohol to remove surface impurities or oil stains, and then wipe the microwave absorbing layer with a siloxane-containing primer to activate the surface of the microwave absorbing layer; then spray the mixture B onto the upper and lower surfaces of the microwave absorbing layer, place it in an oven, and cure it at 80°C for 180 minutes. After curing, the layer structure of "first corrosion resistant layer 1 - microwave absorbing layer 2 - second corrosion resistant layer 3" is obtained. Step 4: Attach the adhesive backing layer 4 to the surface of the second corrosion-resistant layer 3, and let it stand at room temperature for 6 hours to complete the preparation of the broadband absorbing patch with extreme environmental tolerance. See the radar reflectivity curve for details. Figure 3 .
[0029] In this embodiment, the thickness of the first corrosion-resistant layer 1 is 25 μm, the thickness of the microwave absorbing layer 2 is 0.5 mm, the thickness of the second corrosion-resistant layer 3 is 25 μm, and the thickness of the adhesive layer 4 is 69 μm.
[0030] Example 2 This embodiment provides a broadband absorbing patch with extreme environmental resistance, comprising, from top to bottom, a first corrosion-resistant layer 1, an absorbing layer 2, a second corrosion-resistant layer 3, and an adhesive layer 4. The composition and amount of the second corrosion-resistant layer are the same as those of the first corrosion-resistant layer. The first corrosion-resistant layer 1 comprises, by weight, the following components: 60 parts of side-chain vinyl fluorosilicone oil, 3 parts of hydrofluorosilicone oil, 0.6 parts of platinum catalyst, 8 parts of fumed silica, 2 parts of epoxy silane, 8 parts of nano boron nitride, and 18.4 parts of xylene. The microwave absorbing layer 2, by weight, comprises the following components: 21.5 parts of special fluorosilicone (model G413, manufactured by Northwest Rubber & Plastics Research and Design Institute Co., Ltd., with a temperature resistance up to 300℃), 60 parts of flake carbonyl iron powder F01, 15 parts of flake carbonyl iron powder F02, 1.5 parts of vinyltriethoxysilane, and 2 parts of 2,5-dimethyl-2,5-dihexane; The adhesive backing layer 4 uses a common double-sided adhesive high-temperature resistant tape, preferably 3M-300LSE adhesive.
[0031] Furthermore, this embodiment also provides a method for preparing the aforementioned broadband absorbing patch with extreme environmental tolerance, specifically including the following steps: Step 1: Prepare the mixture for the corrosion-resistant layer and the mixture for the microwave-absorbing layer separately; specifically, 1) The specific process for preparing the mixture for the corrosion-resistant layer is as follows: Side-chain vinyl fluorosilicone oil, fumed silica, epoxy silane, nano boron nitride and xylene were added to a mixing container in sequence and mixed and stirred using a stirring mill dispersion machine at a speed of 1000 r / min for 35 min to obtain mixture A; Before spraying, add hydrofluoric silicone oil and platinum catalyst to mixture A, and disperse it using a stirring mill dispersion machine at a speed of 500 r / min for 8 min to obtain mixture B; 2) Prepare the absorbing layer mixture according to the required parts by weight: The flake carbonyl iron powder F01 and half of vinyltriethoxysilane (0.75 parts) were mixed evenly and placed in an oven. The drying temperature was 90°C and the drying time was 75 min to obtain mixture C. The flake carbonyl iron powder F02 and the remaining vinyltriethoxysilane (0.75 parts) were mixed evenly and placed in an oven. The drying temperature was 90°C and the drying time was 75 min to obtain mixture D. Step 2: Mix mixture C, mixture D, 2,5-dimethyl-2,5-dihexane, and special fluorosilicone evenly to obtain mixture E; then pass mixture E through a thin pass 6 times, form a triangular package 7 times, and roll it 4 times in sequence. Then, use an open mill to produce sheets, use a calender to control the thickness, and place them in the mold of a flat vulcanizing machine. At 165°C, mold and vulcanize for 12 minutes. Then, place the molded sheet in an oven and perform a second-stage vulcanization at 155°C for 210 minutes to obtain microwave absorbing layer 2. Step 3: First, wipe the surface of the microwave absorbing layer obtained in Step 2 with alcohol to remove surface impurities or oil stains, and then wipe the microwave absorbing layer with a siloxane-containing primer to activate the surface of the microwave absorbing layer; then spray the mixture B onto the upper and lower surfaces of the microwave absorbing layer, place it in an oven, and cure it at 90°C for 210 minutes. After curing, the layer structure of "first corrosion resistant layer 1 - microwave absorbing layer 2 - second corrosion resistant layer 3" is obtained. Step 4: Attach the adhesive backing layer 4 to the surface of the second corrosion-resistant layer 3, and let it stand at room temperature for 7 hours to complete the preparation of the broadband absorbing patch with extreme environmental tolerance. See the radar reflectivity curve for details. Figure 4 .
[0032] In this embodiment, the thickness of the first corrosion-resistant layer 1 is 20 μm, the thickness of the microwave absorbing layer 2 is 0.5 mm, the thickness of the second corrosion-resistant layer 3 is 20 μm, and the thickness of the adhesive layer 4 is 69 μm.
[0033] Example 3 This embodiment provides a broadband absorbing patch with extreme environmental resistance, comprising, from top to bottom, a first corrosion-resistant layer 1, an absorbing layer 2, a second corrosion-resistant layer 3, and an adhesive layer 4. The composition and amount of the second corrosion-resistant layer are the same as those of the first corrosion-resistant layer. The first corrosion-resistant layer 1 comprises the following components by weight: 65 parts of high vinyl fluorosilicone oil, 5 parts of hydrogen-containing silicone oil, 1 part of platinum catalyst, 8 parts of fumed silica, 3 parts of diaminosilane, 8 parts of nano boron nitride, and 10 parts of butyl acetate. The microwave absorbing layer 2, by weight, comprises the following components: 20 parts of special fluorosilicone (model G413, manufactured by Northwest Rubber & Plastics Research and Design Institute Co., Ltd., with a temperature resistance up to 300℃), 55 parts of flake carbonyl iron powder F01, 20 parts of iron-silicon-chromium alloy powder, 2 parts of vinyltriethoxysilane, and 3 parts of 2,5-dimethyl-2,5-dihexane. The adhesive backing layer 4 uses a common double-sided adhesive high-temperature resistant tape, preferably 3M-300LSE adhesive.
[0034] Furthermore, this embodiment also provides a method for preparing the aforementioned broadband absorbing patch with extreme environmental tolerance, specifically including the following steps: Step 1: Prepare the mixture for the corrosion-resistant layer and the mixture for the microwave-absorbing layer separately; specifically, 1) The specific process for preparing the mixture for the corrosion-resistant layer is as follows: High vinyl fluorosilicone oil, fumed silica, diaminosilane, nano boron nitride and butyl acetate were added to a mixing container in sequence and mixed and stirred using a stirring mill dispersion machine at a speed of 1200 r / min for 30 min to obtain mixture A. Before spraying, add hydrofluoric silicone oil and platinum catalyst to mixture A, and disperse it using a stirring mill dispersion machine at a speed of 600 r / min for 5 min to obtain mixture B; 2) Prepare the absorbing layer mixture according to the required parts by weight: The flake carbonyl iron powder F01 and half of the vinyltriethoxysilane (1 part) were mixed evenly and placed in an oven. The drying temperature was 100℃ and the drying time was 60 min to obtain mixture C. The iron-silicon-chromium alloy powder and the remaining vinyltriethoxysilane (1 part) were mixed evenly and placed in an oven. The drying temperature was 100℃ and the drying time was 60 min to obtain mixture D. Step 2: Mix mixture C, mixture D, 2,5-dimethyl-2,5-dihexane, and special fluorosilicone evenly to obtain mixture E; then process mixture E sequentially through a thin pass 8 times, form a triangular package 10 times, and roll it 6 times, then use an open mill to produce sheets, use a calender to control the thickness, and place it in the mold of a flat vulcanizing machine, and mold and vulcanize at 170°C for 8 minutes. Then place the molded sheet in an oven and perform a second-stage vulcanization at 160°C for 180 minutes to obtain microwave absorbing layer 2. Step 3: First, wipe the surface of the microwave absorbing layer obtained in Step 2 with alcohol to remove surface impurities or oil stains, and then wipe the microwave absorbing layer with a siloxane-containing primer to activate the surface of the microwave absorbing layer; then spray the mixture B onto the upper and lower surfaces of the microwave absorbing layer, place it in an oven, and cure it at 100°C for 240 minutes. After curing, the layer structure of "first corrosion resistant layer 1 - microwave absorbing layer 2 - second corrosion resistant layer 3" is obtained. Step 4: Attach the adhesive backing layer 4 to the surface of the second corrosion-resistant layer 3, and let it stand at room temperature for 8 hours to complete the preparation of the broadband absorbing patch with extreme environmental tolerance. See the radar reflectivity curve for details. Figure 5 .
[0035] In this embodiment, the thickness of the first corrosion-resistant layer 1 is 15 μm, the thickness of the microwave absorbing layer 2 is 0.5 mm, the thickness of the second corrosion-resistant layer 3 is 15 μm, and the thickness of the adhesive layer 4 is 69 μm.
[0036] Comparative Example 1 This comparative example provides a microwave absorbing patch. Based on Example 1, the difference between this comparative example and Example 1 is that the operation of "wiping the microwave absorbing layer with a siloxane-containing primer" is omitted. Otherwise, it is the same as Example 1.
[0037] In this comparative example, the thickness of the first corrosion-resistant layer 1 of the absorbing patch is 25 μm, the thickness of the absorbing layer 2 is 0.5 mm, the thickness of the second corrosion-resistant layer 3 is 25 μm, and the thickness of the adhesive layer 4 is 69 μm.
[0038] Comparative Example 2 This comparative example provides a microwave absorbing patch. The difference between this and Example 1 is that the first corrosion-resistant layer 1 and the second corrosion-resistant layer 3 are removed. The specific preparation process is as follows: The microwave absorbing patch comprises an absorbing layer 2 and an adhesive backing layer 4 arranged sequentially from top to bottom, wherein: The microwave absorbing layer 2 is composed of the following components by mass: 23 parts of special fluorosilicone, 65 parts of flake carbonyl iron powder F01, 10 parts of flake carbonyl iron powder F02, 1 part of vinyltriethoxysilane, and 1 part of 2,5-dimethyl-2,5-dihexane. The adhesive backing layer 4 uses a common double-sided adhesive high-temperature resistant tape on the market, preferably 3M-300LSE adhesive backing. This embodiment also provides a method for preparing a broadband absorbing patch with extreme environmental tolerance, specifically comprising the following steps: S1. Mix the flake carbonyl iron powder F01 and half of the vinyltriethoxysilane (0.5 parts) evenly and place them in an oven. Dry at 80°C for 90 minutes to obtain mixture C. S2. After mixing the flake carbonyl iron powder F02 and the remaining vinyltriethoxysilane (0.5 parts) evenly, place them in an oven and dry at 80°C for 90 minutes to obtain mixture D; S3. Mix mixture C, mixture D, 2,5-dimethyl-2,5-dihexane, and special fluorosilicone evenly to obtain mixture E; finally, mixture E is subjected to thin-passing 4 times, triangular wrapping 5 times, and rolling 2 times in sequence, and then sheeted out using an open mill, with the thickness controlled using a calender, and placed in the mold of a flat vulcanizing machine, and molded and vulcanized at 160°C for 15 minutes. Then, the molded sheet is placed in an oven and subjected to two-stage vulcanization at 150°C for 240 minutes to obtain microwave absorbing layer 2. S4. Attach the adhesive backing to the surface of the microwave absorbing layer and let it stand at room temperature for 6 hours to obtain the microwave absorbing patch.
[0039] In this embodiment, the absorbing layer 2 of the absorbing patch has a thickness of 0.5 mm and the adhesive layer 4 has a thickness of 69 μm.
[0040] To further verify the effectiveness of the technical solution provided by the present invention, the broadband absorbing patches with extreme environmental tolerance prepared in Examples 1-3 and the absorbing patches prepared in Comparative Examples 1-2 were tested. The test results are shown in Table 2 below: Table 2 Combination Figures 3-5 As shown in Table 2 above, the broadband absorbing patch with extreme environmental tolerance prepared by this invention has the characteristics of being thin and light, having excellent environmental resistance (high temperature resistance, damp heat resistance, salt spray resistance), and resistance to oil solvents (RP-3 aviation kerosene fuel, 4109 aviation lubricating oil, YH-15 aviation hydraulic oil, and No. 65 coolant). Furthermore, it breaks through the technical barrier of low adhesion of the surface coating of fluorosilicone-based absorbing patches. At the same time, the patch also has broadband absorbing performance, which can meet the requirements of stealth performance, environmental resistance, and resistance to oil solvents for stealth materials in special occasions.
[0041] In contrast, Comparative Example 1, based on Example 1, omits the step of "wiping the absorbing layer with a siloxane-based primer," resulting in a significant decrease in the adhesion between the corrosion-resistant layer and the absorbing layer, dropping from level 0 in Example 1 to level 4. The main reason for this is that after treating the absorbing layer surface with the siloxane-based primer, the fluorosilicone surface is activated. The isopropanol / alkane solvent in the primer swells the fluorosilicone surface, exposing the inert methyl groups (-CH3), which hydrolyze under ambient humidity, generating active silanol groups (Si-OH), thus increasing the density of bonding sites. Simultaneously, the silane coupling agent in the primer acts as a bridge, forming a covalent bond network of fluorosilicone-O-Si-R-NH-infrared layer, effectively improving the adhesion between the corrosion-resistant layer and the absorbing layer. Furthermore, the siloxane-based primer can reduce the critical surface tension of the absorbing layer, satisfying the coating wetting conditions, thereby improving the interfacial bonding strength between the corrosion-resistant layer and the absorbing layer, overcoming the technical barrier of low adhesion of the coating on the surface of fluorosilicone-based absorbing patches.
[0042] In contrast, Comparative Example 2, based on Example 1, removed the first corrosion-resistant layer 1 and the second corrosion-resistant layer 3, consisting only of the microwave absorbing layer 2 and the adhesive backing layer 4. Test results showed that the patch of Comparative Example 2 exhibited severe corrosion and rusting on its surface after undergoing damp heat, neutral salt spray, and acidic salt spray tests. This is because, without the protection of the first corrosion-resistant layer 1 and the second corrosion-resistant layer 3, the carbonyl iron powder in the microwave absorbing layer corroded and rusted under extreme environmental conditions. Therefore, the first corrosion-resistant layer 1 and the second corrosion-resistant layer 3 in this invention effectively improve the patch's resistance to extreme environments, possessing broad application prospects and market value.
[0043] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.
[0044] It should be understood that the present invention is not limited to the foregoing description, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.
Claims
1. A broadband absorbing patch with extreme environmental tolerance, characterized in that, include: The first corrosion-resistant layer (1), the microwave-absorbing layer (2), the second corrosion-resistant layer (3) and the adhesive layer (4) are arranged sequentially from top to bottom. The composition and amount of the second corrosion-resistant layer (3) are the same as those of the first corrosion-resistant layer (1). The first corrosion-resistant layer (1) comprises the following components by weight: 50 to 65 parts of film-forming substance, 1 to 5 parts of crosslinking agent, 0.1 to 1 part of catalyst, 5 to 10 parts of reinforcing agent, 1 to 3 parts of adhesion promoter, 5 to 10 parts of corrosion-resistant filler, and 10 to 40 parts of solvent; The microwave absorbing layer (2) comprises the following components by weight: 20 to 23 parts of rubber substrate, 55 to 65 parts of first absorbent, 10 to 20 parts of second absorbent, 1 to 2 parts of silane coupling agent, and 1 to 3 parts of vulcanizing agent.
2. The broadband absorbing patch with extreme environmental tolerance according to claim 1, characterized in that, The thickness of the first corrosion-resistant layer (1) is 15μm~25μm; the thickness of the microwave-absorbing layer (2) is 0.5mm~0.55mm; the thickness of the second corrosion-resistant layer (3) is 15μm~25μm; and the thickness of the adhesive layer (4) is 60μm~70μm.
3. The broadband absorbing patch with extreme environmental tolerance according to claim 1, characterized in that, The film-forming substance includes any one of vinyl fluorosilicone oil, side-chain vinyl fluorosilicone oil, and high-vinyl fluorosilicone oil; the crosslinking agent includes any one of hydrogen-containing silicone oil and hydrogen-containing fluorosilicone oil; the catalyst is a platinum catalyst; the reinforcing agent is fumed silica; the adhesion promoter includes any one of epoxy silane and diamino silane; the corrosion-resistant filler includes any one of calcium fluoride and nano boron nitride; and the solvent includes any one of xylene and butyl acetate.
4. The broadband absorbing patch with extreme environmental tolerance according to claim 1, characterized in that, The rubber substrate is a special fluorosilicone; the first absorbent is flake carbonyl iron powder F01; the second absorbent includes any one of flake carbonyl iron powder F02 and iron-silicon-chromium alloy powder; the silane coupling agent is vinyltriethoxysilane; and the vulcanizing agent is 2,5-dimethyl-2,5-dihexane.
5. The broadband absorbing patch with extreme environmental tolerance according to claim 4, characterized in that, The particle size of the flake carbonyl iron powder F02 is 5-8 μm larger than that of the flake carbonyl iron powder F01, and the particle sizes of the two are on the same order of magnitude.
6. The method for preparing a broadband absorbing patch with extreme environmental tolerance according to any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1: Prepare the mixture for the corrosion-resistant layer and the mixture for the microwave absorbing layer respectively; Step 2: Mix the microwave absorbing layer with the mixture, vulcanizing agent and rubber substrate evenly, and mold the evenly mixed mixture. Then, perform two-stage vulcanization on the molded sheet in a drying equipment to obtain the microwave absorbing layer (2). Step 3: First, pre-treat the surface of the absorbing layer to activate it. The corrosion-resistant layer is then sprayed onto the upper and lower surfaces of the microwave-absorbing layer with a mixture, and then placed in a drying equipment for curing. After curing, the preparation of the "first corrosion-resistant layer (1) - microwave-absorbing layer (2) - second corrosion-resistant layer (3)" layer structure is completed. Step 4: Adhesive backing layer (4) is attached to the surface of the second corrosion resistant layer (3) and left to stand at room temperature for 6-8 hours to complete the preparation of broadband absorbing patch with extreme environmental tolerance.
7. The method for preparing a broadband absorbing patch with extreme environmental tolerance according to claim 6, characterized in that, In step 1, the mixture for the corrosion-resistant layer is prepared first, followed by the mixture for the microwave-absorbing layer; or, the mixture for the microwave-absorbing layer is prepared first, followed by the mixture for the corrosion-resistant layer; wherein, 1) The specific process for preparing the mixture for the corrosion-resistant layer is as follows: The film-forming substance, reinforcing agent, adhesion promoter, corrosion-resistant filler and solvent are added to the mixing container in the required weight proportions and mixed and stirred to obtain mixture A; Add the corresponding weight parts of crosslinking agent and catalyst to the mixture A and disperse them to obtain the corrosion-resistant layer mixture B; 2) Prepare the microwave absorbing layer mixture according to the required weight parts. The microwave absorbing layer mixture includes mixture C and mixture D. The specific preparation process is as follows: After the first absorbent and half of the silane coupling agent are mixed evenly and dried, mixture C is obtained; After the second absorbent and the remaining silane coupling agent are mixed evenly and dried, mixture D is obtained.
8. The method for preparing a broadband absorbing patch with extreme environmental tolerance according to claim 7, characterized in that, The mixing speed is 900~1200 r / min, and the mixing time is 30~40 min; The dispersion speed is 400~600 r / min, and the dispersion time is 5~10 min; The drying temperature is 80~100℃, and the drying time is 60~90min; The temperature used for compression molding is 160~170℃, and the time is 8~15min; The vulcanization temperature used in the two-stage vulcanization is 150~160℃, and the time is 180~240min; The curing temperature is 80~100℃, and the curing time is 180~240min.
9. The method for preparing a broadband absorbing patch with extreme environmental tolerance according to claim 7, characterized in that, Step 3 involves pre-treating the surface of the absorbing layer, specifically including: First, wipe the surface of the absorbing layer with alcohol to remove surface impurities or oil stains, and then wipe the surface of the absorbing layer with a siloxane-containing primer to achieve surface activation.
10. The application of the broadband absorbing patch as described in any one of claims 1 to 5 or the broadband absorbing patch prepared by the preparation method as described in any one of claims 6 to 9 in extreme service environments.