Silicon aryl acetylene modified resin-based high temperature resistant microwave absorbing coating and preparation method and application thereof

Abstract

The present invention discloses a silicon aryl acetylene modified resin-based high temperature resistant wave absorbing coating and its preparation method and application, and relates to the technical field of wave absorbing materials. The wave absorbing coating raw materials include an absorbent, a silicon aryl acetylene resin solution, a matrix resin solution, a diluent, a dispersant and an anti-settling agent: the mass ratio of the absorbent, the silicon aryl acetylene resin solution, the matrix resin solution, the diluent, the dispersant and the anti-settling agent is (30-90): (2.5-25): (16.42-122.5): (10-40): (0.3-0.9): (0.3-0.9). The silicon aryl acetylene resin and the organosilicon resin used in the present invention can form intermolecular interactions and chemical bonds, and there is a synergistic effect between the two, which can greatly enhance the heat resistance, flexibility and impact resistance of the wave absorbing coating.

Description

Technical Field

[0001] The present invention relates to the technical field of absorbing materials, and in particular to a silicon aryl yne modified resin-based high-temperature resistant absorbing coating, a preparation method thereof, and applications thereof. Background Art

[0002] With the continuous development of new equipment in my country, high-temperature components such as engine tail nozzles are also facing stealth requirements. However, most of the radar-absorbing coatings currently reported in China are designed for use at room temperature and are not suitable for high-temperature radar absorption scenarios. This greatly limits the application of stealth-absorbing coatings on high-temperature components. The stealth problem of these high-temperature components has become a bottleneck in equipment stealth, and high-temperature radar-absorbing materials are a key technology to solve this bottleneck.

[0003] The prior art discloses a high-temperature resistant absorbing coating that uses silicon carbide micropowder as the main absorber, adjusts the frequency band of the absorbing coating by controlling the ratio of silicon carbide micropowder with different morphologies, and obtains it through heat treatment. This absorbing coating has good high-temperature resistance, but the use of ceramic materials as the matrix narrows the effective bandwidth, weakening the absorbing performance. In addition, ceramic-based absorbing materials have high density, are difficult to process and shape, are brittle, and have poor stability in use. The prior art discloses a conductive polymer-based absorbing material composed of thiophene microspheres and resins such as epoxy resin and polyurethane. This absorbing material has advantages such as thin coating and light weight, but it is difficult to use stably in high-temperature environments. The prior art also discloses a double-layer high-temperature resistant absorbing material that uses materials such as metal oxide fibers and ruthenium dioxide-based conductive glass to prepare an absorbing structure based on a frequency-selective surface. It has good high-temperature resistance and broadband absorbing performance, but its absorbing performance varies significantly with rising temperature. Summary of the Invention

[0004] In response to the shortcomings of the aforementioned background technology, the present invention addresses the bottlenecks in existing high-temperature radar-absorbing coating technology. The present invention provides a silicon aryl acetylene-modified resin-based high-temperature absorbing coating, its preparation method, and its application. This method is simple and controllable, and the resulting coating exhibits excellent high-temperature resistance and radar-absorbing properties, meeting high-temperature requirements.

[0005] The first object of the present invention is to provide a silicon aryl acetylene modified resin-based high-temperature resistant radar absorbing coating, the raw materials of which include an absorbent, a silicon aryl acetylene resin solution, a base resin solution, a diluent, a dispersant, and an anti-settling agent;

[0006] The mass ratio of the absorbent, silicon aromatic resin solution, base resin solution, diluent, dispersant and anti-settling agent is (30-90):(2.5-25):(16.42-122.5):(10-40):(0.3-0.9):(0.3-0.9);

[0007] The absorbent is one or more of an iron-silicon-aluminum alloy powder, an iron-silicon-chromium alloy powder, graphite microspheres, and carbonyl iron powder;

[0008] The matrix resin solution is obtained by mixing matrix resin and xylene, and the solid content of the matrix resin solution is 50% to 70%;

[0009] The matrix resin is silicone resin, epoxy resin, polyamide resin or acrylic resin;

[0010] The diluent is xylene, acetone, chloroform or tetrahydrofuran;

[0011] The dispersant is DISPERBYK-110 dispersant;

[0012] The anti-settling agent is wax.

[0013] Preferably, the silicon aryl acetylene resin solution is obtained by mixing silicon aryl acetylene resin and xylene; the solid content of the silicon aryl acetylene resin solution is 50% to 70%.

[0014] Preferably, the particle size of the absorbent is 5 to 40 μm.

[0015] Preferably, the thickness of the radar absorbing coating is 0.5 to 2 mm.

[0016] A second object of the present invention is to provide a method for preparing a silicon aryl acetylene modified resin-based high-temperature resistant radar absorbing coating, comprising the following steps:

[0017] The absorbent, the silicon aromatic acetylene resin solution, the base resin solution, the diluent, the dispersant and the anti-settling agent are fully mixed to obtain a mixed slurry;

[0018] Under grinding conditions, adding a diluent to the mixed slurry to adjust the viscosity of the mixed slurry to obtain an absorbing coating;

[0019] The microwave-absorbing coating is sprayed on the surface of the substrate and cured to obtain a silicon aryl acetylene modified resin-based high-temperature resistant microwave-absorbing coating.

[0020] Preferably, the mixed slurry is prepared according to the following steps:

[0021] The silicon aryl acetylene resin solution and the matrix resin solution are uniformly blended under stirring conditions to obtain a blended resin solution, and then the absorbent is mixed with the blended resin solution, and a diluent, a dispersant and an anti-settling agent are added under stirring conditions, and stirred for 20 to 40 minutes to obtain the mixed slurry.

[0022] Preferably, under grinding conditions, a diluent is added to the mixed slurry to adjust the viscosity of the mixed slurry to 10-30 Pa·s to obtain the radar absorbing coating.

[0023] Preferably, when spraying the absorbing coating on the surface of the substrate, the diameter of the spray gun is set to 1-2 mm, the spraying pressure is set to 0.2-0.8 MPa, and the spraying distance is set to 10-50 cm;

[0024] The curing temperature is 80~300℃ and the curing time is 1~24h.

[0025] The third object of the present invention is to provide a silicon aryl yne modified resin-based high-temperature resistant wave-absorbing coating for use in absorbing electromagnetic waves.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention provides a silicon aryl acetylene modified resin-based high-temperature resistant radar-absorbing coating, a preparation method, and an application thereof. The radar-absorbing coating introduces silicon aryl acetylene resin as a filler. This is mainly because silicon aryl acetylene resin is a type of organic-inorganic hybrid polymer containing -Si-C≡C-Ar- structural units, is easy to process, and has excellent dielectric properties. In particular, it forms an organic-inorganic hybrid ceramic structure at high temperatures. This ceramic structure is uniformly distributed in the base resin matrix, which can significantly improve the high-temperature resistance of the base resin, so that the radar-absorbing coating is not destroyed in a high-temperature environment, thereby protecting its radar-absorbing properties and having high heat resistance. Silicon aryl acetylene resins are organic-inorganic hybrid polymers. Compared to traditional inorganic heat-resistant fillers, silicon aryl acetylene resins can form bonds with the absorbing coating resin matrix through intermolecular interactions and chemical bonding. The highly reactive alkynyl groups (-C≡C-) in silicon aryl acetylene resins and the active hydrogen (-Si-H-) in methylphenylsilanes can undergo an addition reaction to form alkenyl silanes. This synergistic effect between the silicon aryl acetylene resin filler and the absorbing coating matrix enhances the coating's flexibility and impact resistance. Inorganic heat-resistant fillers, on the other hand, typically have high surface energy and are prone to agglomeration. The mechanical properties of the coating depend largely on the dispersion of the inorganic heat-resistant filler in the matrix and the interface between the filler and the matrix. Furthermore, the density of silicon aryl acetylene resin fillers is lower than that of inorganic heat-resistant fillers, significantly reducing the weight of the absorbing coating, achieving the goal of being both lightweight and thin. The preparation method of the present invention is simple, and the resulting absorbing coating exhibits excellent high-temperature resistance and absorption properties, meeting high-temperature requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The graphs show the real part of the dielectric constant (a), the imaginary part of the dielectric constant (b), the real part of the magnetic permeability (c), and the imaginary part of the magnetic permeability (d) of the high-temperature resistant absorbing coating provided in Example 1 of the present invention and Comparative Example 1 at room temperature and after heat treatment at 350°C / 48h.

[0029] Figure 2The graphs show the real part of the dielectric constant (a), the imaginary part of the dielectric constant (b), the real part of the magnetic permeability (c), and the imaginary part of the magnetic permeability (d) of the high-temperature resistant absorbing coating provided in Example 2 of the present invention and Comparative Example 2 at room temperature and after heat treatment at 350°C / 48h.

[0030] Figure 3 Graphs of the real part of the dielectric constant (a), the imaginary part of the dielectric constant (b), the real part of the magnetic permeability (c), and the imaginary part of the magnetic permeability (d) of the high-temperature resistant absorbing coatings provided in Example 3 of the present invention and Comparative Example 3 at room temperature and after heat treatment at 350°C / 48h are shown.

[0031] Figure 4 Graphs of the real part (a) and imaginary part (b) of the dielectric constant of the high-temperature resistant absorbing coatings provided in Example 4 of the present invention and Comparative Example 4 at room temperature and after heat treatment at 350°C / 48h are shown.

[0032] Figure 5 This is the infrared spectrum of the organosilicon resin, silicon aryl acetylene resin and the product after the two react at high temperature in Example 1 of the present invention. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention is further described below with reference to specific embodiments and drawings, but the embodiments are not intended to limit the present invention.

[0034] The present invention aims to provide a method for preparing and applying a high-temperature absorbing coating based on a silicon-arylacene-modified resin. The silicon-arylacene resin used in this coating is a type of organic-inorganic hybrid polymer containing -Si-C≡C-Ar- structural units. At high temperatures, it forms an organic-inorganic hybrid ceramic structure. This ceramic structure is uniformly distributed within the resin matrix, significantly enhancing the high-temperature resistance of the matrix resin, thereby protecting the absorbing coating from damage in high-temperature environments and preserving its absorbing properties. At room temperature, because inorganic heat-resistant fillers typically have high surface energy and are prone to agglomeration, the mechanical properties of the coating depend largely on the dispersion of the inorganic heat-resistant filler within the matrix and the interface between the filler and the matrix. However, the affinity between the silicon-arylacene resin and the absorbing coating matrix is ​​much greater than that between the inorganic heat-resistant filler and the absorbing coating matrix. The silicon-arylacene resin is well dispersed within the absorbing coating matrix, resulting in the coating having excellent flexibility and impact resistance. The preparation method of the present invention is simple, and the prepared microwave-absorbing coating has excellent high-temperature resistance and microwave-absorbing performance, and can meet high-temperature requirements.

[0035] To achieve the above-mentioned object, the first aspect of the present invention provides a silicon aryl acetylene modified resin-based high-temperature resistant absorbing coating, wherein the raw materials of the absorbing coating include an absorbent, a silicon aryl acetylene resin solution, a matrix resin solution, a diluent, a dispersant, and an anti-settling agent; the mass ratio of the absorbent, silicon aryl acetylene resin solution, the matrix resin solution, the diluent, the dispersant, and the anti-settling agent is (30-90):(2.5-25):(16.42-122.5):(10-40):(0.3-0.9):(0.3-0.9);

[0036] The absorbent is one or more of an iron-silicon-aluminum alloy powder, an iron-silicon-chromium alloy powder, graphite microspheres, and carbonyl iron powder;

[0037] The matrix resin solution is obtained by mixing matrix resin and xylene, and the solid content of the matrix resin solution is 50% to 70%;

[0038] The matrix resin is silicone resin, epoxy resin, polyamide resin or acrylic resin.

[0039] The silicon aryl acetylene resin and organosilicon resin employed in this invention react with the temperature of the absorbing coating to form alkenylsilanes. The highly reactive alkynyl groups (-C≡C-) in the silicon aryl acetylene resin and the reactive hydrogen groups (-Si-H-) in organosilicon resins, such as methylphenyl silicone resin. This allows for intermolecular interactions and chemical bonding between the silicon aryl acetylene resin filler and the resin matrix of the absorbing coating, creating a synergistic effect that significantly enhances the absorbing coating's heat resistance, flexibility, and impact resistance. Furthermore, the density of the silicon aryl acetylene resin filler is lower than that of inorganic heat-resistant fillers, significantly reducing the weight of the absorbing coating, achieving the goal of being both lightweight and thin.

[0040] The silicon aryl acetylene resin solution is obtained by mixing silicon aryl acetylene resin and xylene; the solid content of the silicon aryl acetylene resin solution is 50% to 70%.

[0041] The diluent is xylene, acetone, chloroform or tetrahydrofuran;

[0042] The dispersant is DISPERBYK-110 dispersant;

[0043] The anti-settling agent is wax.

[0044] The particle size of the absorbent is 5 to 40 μm.

[0045] The thickness of the wave-absorbing coating provided by the present invention is 0.5 to 2 mm.

[0046] A second aspect of the present invention provides a method for preparing a silicon aryl yne modified resin-based high-temperature resistant radar absorbing coating, comprising the following steps:

[0047] The absorbent, the silicon aromatic acetylene resin solution, the base resin solution, the diluent, the dispersant and the anti-settling agent are fully mixed to obtain a mixed slurry;

[0048] Under grinding conditions, adding a diluent to the mixed slurry to adjust the viscosity of the mixed slurry to obtain an absorbing coating;

[0049] The microwave-absorbing coating is sprayed on the surface of the substrate and cured to obtain a silicon aryl acetylene modified resin-based high-temperature resistant microwave-absorbing coating.

[0050] The method provided herein comprises thoroughly mixing an absorbent, a silicon aryl acetylene resin solution, a base resin solution, a diluent, an anti-settling agent, and a dispersant to obtain a mixed slurry; adding the diluent to the mixed slurry while stirring to adjust the viscosity of the mixed slurry to obtain an absorbing coating; then spraying the absorbing coating onto the surface of a substrate and curing it in an oven to obtain a high-temperature resistant absorbing coating. By controlling the amounts of the absorbent, silicon aryl acetylene resin solution, base resin solution, diluent, dispersant, and anti-settling agent within the aforementioned ranges, the method produces a mixed slurry in which the absorbent, silicon aryl acetylene resin, and base resin are uniformly dispersed. This ensures that the resulting absorbing coating exhibits both excellent temperature resistance and absorbing properties and can be directly sprayed onto the surface of a structural component.

[0051] The preparation method of the present invention is simple, and the prepared microwave-absorbing coating has excellent high-temperature resistance and microwave-absorbing performance, and can meet high-temperature requirements.

[0052] Wherein, the mixed slurry is prepared according to the following steps:

[0053] The silicon aryl acetylene resin solution and the matrix resin solution are uniformly blended under stirring conditions to obtain a blended resin solution, and then the absorbent is mixed with the blended resin solution, and a diluent, a dispersant and an anti-settling agent are added under stirring conditions, and stirred for 20 to 40 minutes to obtain the mixed slurry.

[0054] Under grinding conditions, a diluent is added to the mixed slurry to adjust the viscosity of the mixed slurry to 10-30 Pa·s to obtain the radar absorbing coating.

[0055] When spraying the absorbing coating on the substrate surface, set the spray gun diameter to 1-2 mm, the spraying pressure to 0.2-0.8 MPa, and the spraying distance to 10-50 cm;

[0056] Specifically, the curing temperature is 80-300°C, and the curing time is 1-24 hours. Specifically, when the matrix resin is a silicone resin, the curing temperature is 240°C / 1 hour; when the matrix resin is an epoxy resin, the curing temperature is 80°C / 24 hours; when the matrix resin is a polyamide resin, the curing temperature is 80°C / 24 hours; and when the matrix resin is an acrylic resin, the curing temperature is 80°C / 24 hours.

[0057] Exemplarily, a method for preparing a silicon aryl yne modified resin-based high-temperature resistant radar absorbing coating comprises:

[0058] S1. Fully mix the absorbent, silicon aromatic acetylene resin solution, base resin solution, diluent, dispersant and anti-settling agent to obtain a mixed slurry;

[0059] In step S1, a silicon aryl acetylene resin solution and a matrix resin solution are uniformly blended under stirring conditions to obtain a blended resin solution. An absorbent is then mixed with the blended resin solution, and a diluent, a dispersant, and an anti-settling agent are added under stirring conditions to obtain a mixed slurry. Specifically, after the silicon aryl acetylene resin solution and the matrix resin solution are mixed, they are stirred at a speed of 400 to 1200 r / min for 10 to 30 minutes to ensure that the two resins are uniformly mixed to obtain a blended resin.

[0060] S2. Under grinding conditions, adding a diluent to the mixed slurry to adjust the viscosity of the mixed slurry to obtain an absorbing coating;

[0061] In step S2, the mixed slurry is placed in a grinder and ground at a speed of 40 to 80 r / min for 2 to 4 hours. During the grinding process, a diluent is added to the mixed slurry to adjust the viscosity of the mixed slurry to 10 to 30 Pa·s, thereby obtaining the radar absorbing coating.

[0062] S3. Spraying the microwave-absorbing coating onto the surface of the substrate and curing it in an oven to obtain a silicon aryl acetylene modified resin-based high-temperature resistant microwave-absorbing coating.

[0063] In step S3, the absorbing coating is placed in a spray can and sprayed on the surface of the substrate 50 to 150 times with a spray gun to obtain a high-temperature resistant absorbing coating; when spraying, the diameter of the spray gun is set to 1 to 2 mm, the spraying pressure is set to 0.2 to 0.8 MPa, and the spraying distance is set to 10 to 50 cm.

[0064] In step S1, the absorbent is sendust alloy powder, sendust alloy powder, graphite microspheres or carbonyl iron powder; the particle size of the absorbent is 5 to 40 μm.

[0065] The present invention controls the particle size of the absorbent within the range of 5 to 40 μm, which not only ensures that the absorbent can be evenly dispersed in the resin solution, but also ensures that the coating has excellent wave absorbing performance.

[0066] The silicon aryl acetylene resin solution is obtained by mixing silicon aryl acetylene resin and xylene; the solid content of the silicon aryl acetylene resin solution is 50%. The base resin solution is obtained by mixing base resin and xylene; the solid content of the base resin solution is 50%. The dispersant is DISPERBYK-110 dispersant, which reduces agglomeration of the absorbent in the absorbing coating and ensures more uniform dispersion. The anti-settling agent is wax, which prevents the absorbent from settling in the absorbing coating.

[0067] In steps S1 and S2, the diluent is xylene, acetone, chloroform, or tetrahydrofuran. In step S1, the diluent primarily serves to fully disperse the absorbent, silicon aryl acetylene resin solution, base resin solution, dispersant, and anti-settling agent to produce a uniformly dispersed mixed slurry. In step S2, the diluent adjusts the viscosity of the mixed slurry to produce an absorbing coating that meets spraying requirements.

[0068] In step S2, the viscosity of the mixed slurry is regulated by adding a diluent. There is no limit on the specific amount of the diluent, as long as the viscosity of the absorbing coating is controlled within the target range. By controlling the viscosity of the absorbing coating within the above range, the obtained slurry is suitable for spraying and can be directly sprayed on the surface of the structural part.

[0069] In step S3, during the spraying process, the number of spraying times, the setting of the caliber of the spray gun, the spraying pressure, and the spraying distance can be adjusted according to actual needs. Generally, limiting the number of spraying times, the setting of the caliber of the spray gun, the spraying pressure, and the spraying distance related parameters to the above range can meet most needs.

[0070] In the present invention, the substrate can be tinplate, aluminum alloy, or stainless steel; the thickness of the high-temperature resistant absorbing coating is 0.5 to 2 mm. The substrate material and the thickness of the absorbing coating used in the present invention can be selected based on actual needs and application scenarios, and the absorbing coating of the aforementioned thickness can be obtained by combining appropriate spraying parameters.

[0071] When the matrix resin used in the present invention is a silicone resin, the curing temperature is 240°C / 1h; when the matrix resin is an epoxy resin, the curing temperature is 80°C / 24h; when the matrix resin is a polyamide resin, the curing temperature is 80°C / 24h; when the matrix resin is an acrylic resin, the curing temperature is 80°C / 24h.

[0072] The microwave-absorbing coating prepared by the present invention can be directly sprayed on the surface of a structural part. The formed microwave-absorbing coating has excellent temperature resistance and microwave-absorbing performance, and the coating is not easy to crack.

[0073] A third aspect of the present invention provides an application of a silicon aryl yne modified resin-based high-temperature resistant wave-absorbing coating in absorbing electromagnetic waves.

[0074] It should be noted that the experimental methods used in the present invention are all conventional methods unless otherwise specified; the reagents and materials used are all commercially available unless otherwise specified.

[0075] Wave absorption performance test standard: refer to GJB2038A-2011.

[0076] Example 1

[0077] S1. After mixing 51.4 g of silicon aryl acetylene resin solution and 154.28 g of organosilicon resin solution, the mixture was stirred at a speed of 800 r / min for 30 min to obtain a blended resin solution. Under stirring conditions, 420 g of sendust powder, 10 g of xylene, 4.2 g of DISPERBYK-110, and 4.2 g of wax were added to the blended resin solution and stirred for 30 min to obtain a mixed slurry.

[0078] The average particle size of the sendust alloy powder is 25 μm; the solid content of the silicon arylacetylene resin solution is 50%; and the solid content of the silicone resin solution is 50%.

[0079] S2. Place the mixed slurry into a grinder and grind it at a speed of 60 r / min for 3 h. During the grinding process, add xylene to the mixed slurry to adjust the viscosity of the mixed slurry to 30 Pa·s to obtain an absorbing coating. When adjusting the viscosity, the amount of xylene added is 20 g.

[0080] S3. Weigh 500 g of the absorbing coating into a spray can and spray it on the tinplate surface with a spray gun to obtain a high-temperature absorbing coating with a thickness of 1.5 mm. When spraying, set the spray gun diameter to 1.5 mm, the pressure to 0.7 MPa, and the spray gun distance to 25 cm.

[0081] The high-temperature resistant radar-absorbing coating can be directly sprayed on the surface of a structural part. The obtained radar-absorbing coating has excellent temperature resistance and radar-absorbing properties, and the coating is not easy to crack.

[0082] Example 2

[0083] S1. After mixing 51.4 g of silicon aryl acetylene resin solution and 154.28 g of organosilicon resin solution, the mixture was stirred at a speed of 800 r / min for 30 min to obtain a blended resin solution. Under stirring conditions, 420 g of iron-silicon-chromium alloy powder, 5 g of xylene, 4.2 g of DISPERBYK-110, and 4.2 g of wax were added to the blended resin solution and stirred for 30 min to obtain a mixed slurry.

[0084] The average particle size of the iron-silicon-chromium alloy powder is 8 μm; the solid content of the silicon-arylacetylene resin solution is 50%; and the solid content of the organic silicone resin solution is 50%.

[0085] S2. Place the mixed slurry into a grinder and grind it at a speed of 60 r / min for 3 h. During the grinding process, add xylene to the mixed slurry and adjust the viscosity of the mixed slurry to 30 Pa·s to obtain an absorbing coating. When adjusting the viscosity, the amount of xylene added is 15 g.

[0086] S3. Weigh 500 g of the absorbing coating into a spray can and spray it on the tinplate surface with a spray gun to obtain a high-temperature absorbing coating with a thickness of 1.5 mm. When spraying, set the spray gun diameter to 1.5 mm, the pressure to 0.7 MPa, and the spray gun distance to 25 cm.

[0087] The high-temperature resistant radar-absorbing coating can be directly sprayed on the surface of a structural part. The obtained radar-absorbing coating has excellent temperature resistance and radar-absorbing properties, and the coating is not easy to crack.

[0088] Example 3

[0089] S1. After mixing 51.4 g of silicon aryl acetylene resin solution and 154.28 g of organosilicon resin solution, stir at 800 r / min for 30 min to obtain a blended resin solution. Under stirring conditions, 420 g of carbonyl iron powder, 10 g of xylene, 4.2 g of DISPERBYK-110, and 4.2 g of wax were added to the blended resin solution and stirred for 30 min to obtain a mixed slurry.

[0090] The average particle size of the carbonyl iron powder is 25 μm; the solid content of the silicon aryl acetylene resin solution is 50%; and the solid content of the organic silicone resin solution is 50%.

[0091] S2. Place the mixed slurry into a grinder and grind it at a speed of 60 r / min for 3 h. During the grinding process, add xylene to the mixed slurry to adjust the viscosity of the mixed slurry to 30 Pa·s to obtain an absorbing coating. When adjusting the viscosity, the amount of xylene added is 20 g.

[0092] S3. Weigh 500 g of the absorbing coating into a spray can and spray it on the tinplate surface with a spray gun to obtain a high-temperature absorbing coating with a thickness of 1.5 mm. When spraying, set the spray gun diameter to 1.5 mm, the pressure to 0.7 MPa, and the spray gun distance to 25 cm.

[0093] The high-temperature resistant radar-absorbing coating can be directly sprayed on the surface of a structural part. The obtained radar-absorbing coating has excellent temperature resistance and radar-absorbing properties, and the coating is not easy to crack.

[0094] Example 4

[0095] S1. Mix 120 g of silicon aryl acetylene resin solution and 660 g of organosilicon resin solution, stir at 800 r / min for 30 min to obtain a blended resin solution. Add 180 g of graphite microspheres, 5 g of xylene, 1.8 g of DISPERBYK-110, and 1.8 g of wax to the blended resin solution under stirring, and stir for 30 min to obtain a mixed slurry.

[0096] The average particle size of the graphite microspheres is 15 μm; the solid content of the silicon aromatic acetylene resin solution is 50%; and the solid content of the organic silicone resin solution is 50%.

[0097] S2. Place the mixed slurry into a grinder and grind it at a speed of 60 r / min for 3 h. During the grinding process, add xylene to the mixed slurry to adjust the viscosity of the mixed slurry to 30 Pa·s to obtain an absorbing coating. When adjusting the viscosity, the amount of xylene added is 25 g.

[0098] S3. Weigh 500 g of the absorbing coating into a spray can and spray it on the tinplate surface with a spray gun to obtain a high-temperature absorbing coating with a thickness of 1.5 mm. When spraying, set the spray gun diameter to 1.5 mm, the pressure to 0.7 MPa, and the spray gun distance to 25 cm.

[0099] The high-temperature resistant radar-absorbing coating can be directly sprayed on the surface of a structural part. The resulting radar-absorbing coating has excellent heat resistance and radar-absorbing properties, and is not prone to cracking.

[0100] Comparative Example 1

[0101] Comparative Example 1 is the same as Example 1, except that: in step S1, 154.28 g of the silicone resin solution is taken, 420 g of sendust powder, 10 g of xylene, 4.2 g of DISPERBYK-110, and 4.2 g of wax are added to the silicone resin solution, and the mixture is stirred at a speed of 800 r / min for 30 min to obtain a mixed slurry.

[0102] Comparative Example 2

[0103] Comparative Example 2 is the same as Example 2, except that: in step S1, 154.28 g of the silicone resin solution was taken, 420 g of iron-silicon-chromium alloy powder, 5 g of xylene, 4.2 g of DISPERBYK-110, and 4.2 g of wax were added to the silicone resin solution, and the mixture was stirred at a speed of 800 r / min for 30 min to obtain a mixed slurry.

[0104] Comparative Example 3

[0105] Comparative Example 3 is the same as Example 3, except that: in step S1, 154.28 g of the silicone resin solution was taken, 420 g of carbonyl iron powder, 10 g of xylene, 4.2 g of DISPERBYK-110, and 4.2 g of wax were added to the silicone resin solution, and the mixture was stirred at a speed of 800 r / min for 30 min to obtain a mixed slurry.

[0106] Comparative Example 4

[0107] Comparative Example 4 is the same as Example 4, except that: in step S1, 660 g of the silicone resin solution was taken, 180 g of graphite microspheres, 5 g of xylene, 1.8 g of DISPERBYK-110, and 1.8 g of wax were added to the silicone resin solution, and the mixture was stirred at a speed of 800 r / min for 30 min to obtain a mixed slurry.

[0108] In order to illustrate the performance of the radar absorbing coating provided by the present invention, a description is given with reference to the accompanying drawings.

[0109] The test performances of the silicon aryl yne modified organosilicon-based microwave absorbing coatings provided in Examples 1 to 4 and the unmodified organosilicon-based microwave absorbing coatings provided in Comparative Examples 1 to 4 are shown in Table 1.

[0110] Table 1 Test performance of silicon aryl acetylene modified silicone-based microwave absorbing coating and unmodified silicone-based microwave absorbing coating

[0111]

[0112] As shown in Table 1, the adhesion, flexibility, and impact resistance of the silicon-arylacetylene-modified and unmodified silicone resin-based absorbing coatings at room temperature are similar. However, after heat treatment at 350°C for 48 hours, the adhesion, flexibility, and impact resistance of the unmodified silicone resin-based absorbing coating significantly degraded, and the coating also exhibited cracking and powdering. However, the adhesion, flexibility, and impact resistance of the silicon-arylacetylene-modified silicone resin-based absorbing coating declined somewhat, but the coating remained intact, without cracking or powdering. This indicates that the unmodified silicone resin-based absorbing coating is difficult to withstand long-term exposure to 350°C, resulting in deterioration in performance. This further demonstrates that without the silicon-arylacetylene resin solution blending modification, the unmodified silicone resin-based absorbing coating exhibits poorer heat resistance.

[0113] Figure 1 The graphs show the real part of the dielectric constant (a), the imaginary part of the dielectric constant (b), the real part of the magnetic permeability (c), and the imaginary part of the magnetic permeability (d) of the high-temperature resistant absorbing coating provided in Example 1 of the present invention and Comparative Example 1 at room temperature and after heat treatment at 350°C / 48h.

[0114] like Figure 1As shown, the dielectric constant and magnetic permeability of the silicon aryl yne modified silicone resin-based absorbing coating provided in Example 1 are compared with the unmodified silicone resin-based absorbing coating provided in Comparative Example 1 at room temperature and after heat treatment at 350°C. The changes are small, indicating that the silicon aryl yne modified silicone resin-based absorbing coating can withstand 350°C without deterioration in absorbing performance.

[0115] Figure 2 The graphs show the real part of the dielectric constant (a), the imaginary part of the dielectric constant (b), the real part of the magnetic permeability (c), and the imaginary part of the magnetic permeability (d) of the high-temperature resistant absorbing coating provided in Example 2 of the present invention and Comparative Example 2 at room temperature and after heat treatment at 350°C / 48h.

[0116] like Figure 2 As shown, the dielectric constant and magnetic permeability of the silicon-aryl-yne modified silicone resin-based absorbing coating provided in Example 2 are similar at room temperature and after heat treatment at 350°C, with little change, compared with the unmodified silicone resin-based absorbing coating provided in Comparative Example 2. This indicates that the silicon-aryl-yne modified silicone resin-based absorbing coating can withstand 350°C without deterioration in absorbing performance.

[0117] Figure 3 Graphs of the real part of the dielectric constant (a), the imaginary part of the dielectric constant (b), the real part of the magnetic permeability (c), and the imaginary part of the magnetic permeability (d) of the high-temperature resistant absorbing coatings provided in Example 3 of the present invention and Comparative Example 3 at room temperature and after heat treatment at 350°C / 48h are shown.

[0118] like Figure 3 As shown, the dielectric constant and magnetic permeability of the silicon aryl yne modified silicone resin-based absorbing coating provided in Example 3 are significantly different before and after heat treatment at 350°C compared with the unmodified silicone resin-based absorbing coating provided in Comparative Example 3 at room temperature. This is because the carbonyl iron powder is oxidized at high temperature.

[0119] Figure 4 Graphs of the real part (a) and imaginary part (b) of the dielectric constant of the high-temperature resistant absorbing coatings provided in Example 4 of the present invention and Comparative Example 4 at room temperature and after heat treatment at 350°C / 48h are shown.

[0120] like Figure 4 As shown, the dielectric constants of the silicon aryl yne modified silicone resin-based absorbing coating provided in Example 4 and the unmodified silicone resin-based absorbing coating provided in Comparative Example 4 are similar at room temperature and after heat treatment at 350°C, with little change. This indicates that the silicon aryl yne modified silicone resin-based absorbing coating can withstand 350°C without deterioration in absorbing performance.

[0121] Figure 5 This is the infrared spectrum of the product of the reaction of the silicone resin (organic silicon), silicon aryl acetylene resin (PSA) and the two (organic silicon + PSA) at high temperature in Example 1 of the present invention. Figure 5 It can be seen that the more active alkynyl group (-C≡C-) in the silicon aryl acetylene resin is at 2200 cm -1 There is an obvious absorption peak at 2100 cm-1. Organic silicone resins such as methylphenyl silicone resin contain active hydrogen (-Si-H-) at 2100 cm-1. -1 There is an obvious absorption peak at 1680cm after the reaction of silicone resin and silicon aryl acetylene resin. -1 There is an obvious absorption peak at , indicating that the alkynyl group (-C≡C-) and active hydrogen (-Si-H-) have undergone an addition reaction to form a carbon-carbon double bond (-C=C-), proving that the two have reacted successfully.

[0122] In summary, the present invention provides a preparation and application of a silicon aryl acetylene-modified resin-based high-temperature absorbing coating. The method comprises thoroughly mixing an absorbent, a silicon aryl acetylene resin solution, a matrix resin solution, a diluent, an anti-settling agent, and a dispersant to obtain a mixed slurry; adding the diluent to the mixed slurry under stirring conditions to adjust the viscosity of the mixed slurry to obtain an absorbing coating; then spraying the absorbing coating onto the surface of a substrate and curing it in an oven to obtain a high-temperature absorbing coating. At room temperature, the affinity between the silicon aryl acetylene resin and the absorbing coating matrix is ​​much greater than the affinity between the inorganic heat-resistant filler and the absorbing coating matrix. The silicon aryl acetylene resin is well dispersed within the absorbing coating matrix, resulting in the absorbing coating having excellent flexibility and impact resistance. As the temperature of the absorbing coating increases, intermolecular interactions and chemical bonds can form between the silicon aryl acetylene resin filler and the absorbing coating resin matrix, creating a synergistic effect that can significantly enhance the heat resistance, flexibility, and impact resistance of the absorbing coating. In addition, the density of silicon aromatic acetylene resin filler is lower than that of inorganic heat-resistant filler, which can greatly reduce the weight of the absorbing coating and achieve the goal of "light and thin".

[0123] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A silicon aryl acetylene modified resin-based high temperature resistant radar absorbing coating, characterized in that: The raw materials of the wave absorbing coating include absorbent, silicon aromatic acetylene resin solution, matrix resin solution, diluent, dispersant and anti-settling agent; The mass ratio of the absorbent, silicon aromatic acetylene resin solution, base resin solution, diluent, dispersant and anti-settling agent is (30-90):(2.5-25):(16.42-122.5):(10-40):(0.3-0.9):(0.3-0.9); The absorbent is one or more of iron-silicon-aluminum alloy powder, iron-silicon-chromium alloy powder, graphite microspheres, and carbonyl iron powder; The matrix resin solution is obtained by mixing a matrix resin and xylene, and the solid content of the matrix resin solution is 50% to 70%; The base resin is an organic silicon resin containing an active hydrogen group -Si-H-; The diluent is xylene, acetone, chloroform or tetrahydrofuran; The dispersant is DISPERBYK-110 dispersant; The anti-settling agent is wax; The silicon aryl acetylene resin solution is obtained by mixing silicon aryl acetylene resin and xylene; the solid content of the silicon aryl acetylene resin solution is 50% to 70%; The particle size of the absorbent is 5 to 40 μm; The thickness of the radar absorbing coating is 0.5 to 2 mm.

2. A method for preparing the silicon aryl acetylene modified resin-based high temperature resistant radar absorbing coating according to claim 1, characterized in that: The following steps are involved: Fully mixing the absorbent, the silicon aromatic acetylene resin solution, the base resin solution, the diluent, the dispersant and the anti-settling agent to obtain a mixed slurry; Under grinding conditions, adding a diluent to the mixed slurry to adjust the viscosity of the mixed slurry to obtain an absorbing coating; The microwave-absorbing coating is sprayed on the surface of the substrate and cured to obtain a silicon aryl acetylene modified resin-based high-temperature resistant microwave-absorbing coating.

3. The method for preparing the silicon aryl acetylene modified resin-based high temperature resistant radar absorbing coating according to claim 2, characterized in that: The mixed slurry is prepared according to the following steps: The silicon aromatic acetylene resin solution and the matrix resin solution are uniformly blended under stirring conditions to obtain a blended resin solution, and then the absorbent is mixed with the blended resin solution, and a diluent, a dispersant and an anti-settling agent are added under stirring conditions, and stirred for 20 to 40 minutes to obtain the mixed slurry.

4. The method for preparing the silicon aryl acetylene modified resin-based high temperature resistant radar absorbing coating according to claim 3, characterized in that: Under the grinding condition, a diluent is added to the mixed slurry to adjust the viscosity of the mixed slurry to 10-30 Pa·s to obtain the radar absorbing coating.

5. The method for preparing the silicon aryl acetylene modified resin-based high temperature resistant radar absorbing coating according to claim 4, characterized in that: When spraying the absorbing coating on the substrate surface, the caliber of the spray gun is set to 1-2 mm, the spraying pressure is set to 0.2-0.8 MPa, and the spraying distance is set to 10-50 cm; The curing temperature is 80~300℃ and the curing time is 1~24h.

6. Use of the silicon aryl acetylene modified resin-based high temperature resistant wave absorbing coating according to claim 1 in absorbing electromagnetic waves.

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