Silicon aryne modified resin-based high-temperature-resistant wave-absorbing coating as well as preparation method and application thereof

Abstract

The invention discloses a silicon aryne modified resin-based high-temperature-resistant wave-absorbing coating as well as a preparation method and application thereof, and relates to the technical field of wave-absorbing materials. The wave-absorbing coating is prepared from the following raw materials: an absorbent, a silicon aryne resin solution, a matrix resin solution, a diluent, a dispersing agent and an anti-settling agent, wherein the mass ratio of the absorbent to the silicon aryne resin solution to the matrix resin solution to the diluent to the dispersing agent to the anti-settling agent is (30 to 90) to (2.5 to 25) to (16.42 to 122.5) to (10 to 40) to (0.3 to 0.9) to (0.3 to 0.9). Intermolecular interaction and chemical bonding can be formed between the silicon aryne resin and the organic silicon resin, and the heat resistance, the flexibility and the impact resistance of the wave-absorbing coating can be greatly enhanced due to the synergistic effect between the silicon aryne resin and the organic silicon resin.

Description

Technical Field

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

[0002] With the continuous development of new equipment in my country, high-temperature components such as engine tail nozzles have also put forward stealth requirements. However, most of the absorbing coatings reported in China are used under normal temperature conditions and are not suitable for high-temperature absorbing scenarios. This has largely limited the application of stealth absorbing coatings on high-temperature components. The stealth problem of these high-temperature components has become a bottleneck problem for equipment stealth, and high-temperature absorbing materials are the key technology to solve this bottleneck problem.

[0003] The prior art discloses a method of using silicon carbide micropowder as the main absorber, adjusting the frequency band of the absorbing coating by controlling the proportion of silicon carbide micropowder with different morphologies, and obtaining a high-temperature resistant absorbing coating by heat treatment. The absorbing coating has good high-temperature resistance, but using ceramic materials as the matrix will narrow the effective bandwidth and weaken the absorbing performance. In addition, the ceramic-based absorbing material has a high density, is difficult to process and is brittle, and has poor stability in use. The prior art discloses a conductive polymer-based absorbing material, which is composed of thiophene microspheres and resins such as epoxy resin and polyurethane. The absorbing material has the advantages of thin coating and light weight, but is difficult to use stably in a high-temperature environment. The prior art also discloses a high-temperature resistant absorbing material with a double-layer structure, which uses materials such as metal oxide fibers and ruthenium dioxide conductive glass to prepare an absorbing structure based on a frequency selective surface, which has good high-temperature resistance and broadband absorbing performance, but its absorbing performance changes greatly with temperature rise. Summary of the invention

[0004] In view of the shortcomings of the above-mentioned background technology, the present invention addresses the bottleneck problem of the existing high-temperature absorbing coating technology. The present invention provides a silicon aryl acetylene modified resin-based high-temperature absorbing coating and its preparation method and application. The method is simple and controllable, and the prepared coating has excellent high-temperature resistance and absorbing performance, which can meet 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 radar absorbing coating raw materials include absorbent, silicon aryl acetylene resin solution, base resin solution, diluent, dispersant and anti-settling agent; The mass ratio of the absorbent, the silicon aromatic acetylene resin solution, the base 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 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 matrix resin is silicone resin, epoxy resin, polyamide resin or acrylic resin; The diluent is xylene, acetone, chloroform or tetrahydrofuran; The dispersant is DISPERBYK-110 dispersant; The anti-settling agent is wax.

[0006] 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%.

[0007] Preferably, the particle size of the absorbent is between 5 and 40 μm.

[0008] Preferably, the thickness of the radar absorbing coating is 0.5-2 mm.

[0009] The 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: 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; 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.

[0010] Preferably, 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.

[0011] 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.

[0012] Preferably, when the absorbing coating is sprayed on the surface of the substrate, 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.

[0013] The third object of the present invention is to provide a silicon aryl acetylene modified resin-based high temperature resistant wave absorbing coating for use in absorbing electromagnetic waves.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 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, mainly because silicon aryl acetylene resin is a type of organic-inorganic hybrid polymer containing -Si-C≡C-Ar- structural units, has easy processing and excellent dielectric properties, and especially forms an organic-inorganic hybrid ceramic structure at high temperature. The ceramic structure is uniformly distributed in a base resin matrix, which can greatly 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 performance and having high heat resistance. Silicon aryl acetylene resin is an organic-inorganic hybrid polymer. Compared with traditional inorganic heat-resistant fillers, silicon aryl acetylene resin and the absorbing coating resin matrix can interact with each other through intermolecular interactions and chemical bonding. Silicon aryl acetylene resin contains highly active alkynyl groups (-C≡C-), and methylphenyl silicon contains active hydrogen (-Si-H-). The two active groups can undergo addition reactions to generate alkenyl silanes. There is a synergistic effect between the silicon aryl acetylene resin filler and the absorbing coating matrix, which can enhance the flexibility and impact resistance of the absorbing coating. Inorganic heat-resistant fillers usually have high surface energy and are very easy to agglomerate. The mechanical properties of the coating depend to a large extent on the dispersion state of the inorganic heat-resistant filler in the matrix and the interface between the inorganic heat-resistant filler and the matrix. In addition, the density of the silicon aryl acetylene resin filler is lower than that of the inorganic heat-resistant filler, which can greatly reduce the weight of the absorbing coating and achieve the goal of "light and thin". The preparation method of the present invention is simple, and the obtained absorbing coating has excellent high temperature resistance and absorbing performance, which can meet high temperature requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The graphs are 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 coating provided in Example 1 of the present invention and Comparative Example 1 at room temperature and after heat treatment at 350°C / 48h.

[0016] Figure 2 The graphs are 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 coating provided in Example 2 of the present invention and Comparative Example 2 at room temperature and after heat treatment at 350°C / 48h.

[0017] Figure 3The graphs are 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 coating provided in Example 3 of the present invention and Comparative Example 3 at room temperature and after heat treatment at 350°C / 48h.

[0018] Figure 4 The graphs are the real part (a) and imaginary part (b) of the dielectric constant of the high temperature resistant absorbing coating provided by Example 4 of the present invention and Comparative Example 4 at room temperature and after heat treatment at 350°C / 48h.

[0019] Figure 5 This is the infrared spectrum of the organic silicon resin, the silicon aryl acetylene resin and the product after the two react at high temperature in Example 1 of the present invention. DETAILED DESCRIPTION

[0020] 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 in conjunction with specific embodiments and drawings, but the embodiments are not intended to limit the present invention.

[0021] The purpose of the present invention is to provide a preparation and application of a silicon aryl acetylene modified resin-based high temperature resistant wave absorbing coating. The silicon aryl acetylene resin used in the wave absorbing coating is a type of organic-inorganic hybrid polymer containing -Si-C≡C-Ar- structural units, which forms an organic-inorganic hybrid ceramic structure at high temperature. The ceramic structure is evenly distributed in the resin matrix, which can greatly improve the high temperature resistance of the matrix resin, so that the wave absorbing coating is not destroyed in a high temperature environment, thereby protecting its wave absorbing performance. Under normal temperature conditions, since inorganic heat-resistant fillers usually have high surface energy and are very easy to agglomerate, the mechanical properties of the coating depend to a large extent on the dispersion state of the inorganic heat-resistant fillers in the matrix and the interface between the inorganic heat-resistant fillers and the matrix. However, the affinity between the silicon aryl acetylene resin and the wave absorbing coating matrix is ​​much greater than the affinity between the inorganic heat-resistant fillers and the wave absorbing coating matrix. The silicon aryl acetylene resin is well dispersed between the wave absorbing coating matrix, so that the wave absorbing coating has 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.

[0022] In order 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, the 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 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 matrix resin is silicone resin, epoxy resin, polyamide resin or acrylic resin.

[0023] The silicon aryl acetylene resin and the organosilicon resin used in the present invention, as the temperature of the absorbing coating increases, the highly active acetylenic group (-C≡C-) in the silicon aryl acetylene resin and the active hydrogen (-Si-H-) in the organosilicon resin such as methylphenyl silicone resin, the two active groups can undergo addition reaction to generate alkenyl silane. Therefore, the silicon aryl acetylene resin filler and the resin matrix of the absorbing coating can form intermolecular interaction and chemical bonding, and there is a synergistic effect between the two, which can greatly enhance the heat resistance, flexibility and impact resistance of the absorbing coating. In addition, the density of the silicon aryl acetylene resin filler is lower than that of the inorganic heat-resistant filler, which can greatly reduce the weight of the absorbing coating and achieve the goal of "light and thin".

[0024] 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%.

[0025] The diluent is xylene, acetone, chloroform or tetrahydrofuran; The dispersant is DISPERBYK-110 dispersant; The anti-settling agent is wax.

[0026] The particle size of the absorbent is 5 to 40 μm.

[0027] The thickness of the wave absorbing coating provided by the invention is 0.5 to 2 mm.

[0028] The second aspect of the present invention provides a method for preparing a silicon aryl acetylene modified resin-based high temperature resistant radar absorbing coating, comprising the following steps: 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; 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.

[0029] The method provided by the present invention comprises fully 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; under stirring conditions, adding a diluent to the mixed slurry to adjust the viscosity of the mixed slurry to obtain an absorbing coating; then spraying the absorbing coating on the surface of the substrate, curing it in an oven, and obtaining a high-temperature resistant absorbing coating. The present invention controls the amount of the absorbent, silicon aryl acetylene resin solution, base resin solution, diluent, dispersant and anti-settling agent within the above range, that is, obtaining a mixed slurry in which the absorbent, silicon aryl acetylene resin and base resin are uniformly dispersed, ensuring that the obtained absorbing coating has excellent temperature resistance and absorbing performance at the same time, and can be directly sprayed on the surface of the structural part.

[0030] 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.

[0031] Wherein, 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.

[0032] 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.

[0033] 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; Specifically, the curing temperature is 80-300°C, and the curing time is 1-24 hours. When the matrix resin is silicone resin, the curing temperature is 240°C / 1 hour; when the matrix resin is epoxy resin, the curing temperature is 80°C / 24 hours; when the matrix resin is polyamide resin, the curing temperature is 80°C / 24 hours; when the matrix resin is acrylic resin, the curing temperature is 80°C / 24 hours.

[0034] Exemplarily, a method for preparing a silicon aryl acetylene modified resin-based high temperature resistant radar absorbing coating comprises: S1. Fully mix 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; In step S1, 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 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 make the two resins uniformly mixed to obtain a blended resin.

[0035] S2. Under grinding conditions, adding a diluent to the mixed slurry to adjust the viscosity of the mixed slurry to obtain an absorbing coating; In step S2, the mixed slurry is put into a grinder and ground at a speed of 40 to 80 r / min for 2 to 4 hours, and a diluent is added to the mixed slurry under the grinding condition to adjust the viscosity of the mixed slurry to 10 to 30 Pa·s to obtain the radar absorbing coating; 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.

[0036] In step S3, the absorbing coating is put into 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 caliber 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.

[0037] In step S1, the absorbent is an iron-silicon-aluminum alloy powder, an iron-silicon-chromium alloy powder, graphite microspheres or carbonyl iron powder; and the particle size of the absorbent is 5 to 40 μm.

[0038] The present invention controls the particle size of the absorbent within the range of 5 to 40 μm, which can not only ensure that the absorbent can be evenly dispersed in the resin solution, but also ensure that the coating has excellent wave absorbing performance.

[0039] 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 matrix resin solution is obtained by mixing matrix resin and xylene; the solid content of the matrix resin solution is 50%. The dispersant is DISPERBYK-110 dispersant, which reduces the agglomeration of the absorbent in the absorbing coating and makes the dispersion more uniform. The anti-settling agent is wax, which prevents the absorbent from settling in the absorbing coating.

[0040] In steps S1 and S2, the diluent is xylene, acetone, chloroform or tetrahydrofuran. In step S1, the diluent is mainly used to fully disperse the absorbent, the silicon aryl acetylene resin solution, the matrix resin solution, the dispersant and the anti-settling agent to obtain a uniformly dispersed mixed slurry; in step S2, the diluent is used to adjust the viscosity of the mixed slurry to obtain an absorbing coating that meets the spraying requirements.

[0041] In step S2, the viscosity of the mixed slurry is regulated by adding a diluent, and the specific amount of the diluent is not limited, as long as the viscosity of the absorbing coating is controlled within the target range; when the viscosity of the absorbing coating is controlled within the above range, the obtained slurry is suitable for spraying and can be directly sprayed on the surface of the structural part.

[0042] In step S3, during the spraying process, the number of spraying times, 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 caliber of the spray gun, the spraying pressure, and the spraying distance related parameters to the above range can meet most needs.

[0043] The substrate in the present invention can be tinplate, aluminum alloy or stainless steel; the thickness of the high temperature resistant absorbing coating is 0.5 to 2 mm. The thickness of the substrate material and the absorbing coating used in the present invention can be selected according to actual needs and application scenarios, and the absorbing coating of the above thickness can be obtained by combining corresponding spraying parameters.

[0044] 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.

[0045] The radar absorbing coating prepared by the present invention can be directly sprayed on the surface of a structural part, and the formed radar absorbing coating has excellent temperature resistance and radar absorbing performance, and the coating is not easy to crack.

[0046] A third aspect of the present invention provides an application of a silicon aryl acetylene modified resin-based high temperature resistant wave absorbing coating in absorbing electromagnetic waves.

[0047] 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.

[0048] Wave absorption performance test standard: refer to GJB2038A-2011.

[0049] Example 1 S1. Take 51.4 g of silicon aryl acetylene resin solution and 154.28 g of organosilicon resin solution, mix them, and stir them at a speed of 800 r / min for 30 min to obtain a blended resin solution. Under stirring conditions, add 420 g of sendust powder, 10 g of xylene, 4.2 g of DISPERBYK-110 and 4.2 g of wax to the blended resin solution, stir for 30 min to obtain a mixed slurry; The average particle size of the sendust alloy powder is 25 μm; the solid content of the silicon aromatic acetylene resin solution is 50%; and the solid content of the silicone resin solution is 50%.

[0050] S2. Put the mixed slurry into a grinder and grind it at a speed of 60 r / min for 3 hours. During the grinding, add xylene to the mixed slurry to adjust the viscosity of the mixed slurry to 30 Pa·s to obtain an absorbing coating; wherein, when adjusting the viscosity, the amount of xylene added is 20 g.

[0051] S3, weigh 500g of absorbing paint and put it into a spray can, and spray it on the tinplate surface with a spray gun to obtain a high temperature resistant absorbing coating with a thickness of 1.5mm; when spraying, set the spray gun caliber to 1.5mm, the pressure to 0.7MPa, and the spray gun distance to 25cm; The high temperature resistant radar absorbing coating can be directly sprayed on the surface of a structural part, and the obtained radar absorbing coating has excellent temperature resistance and radar absorbing performance, and the coating is not easy to crack.

[0052] Example 2 S1. Take 51.4 g of silicon aryl acetylene resin solution and 154.28 g of organosilicon resin solution, mix them, and stir them at a speed of 800 r / min for 30 min to obtain a blended resin solution. Under stirring conditions, add 420 g of iron-silicon-chromium alloy powder, 5 g of xylene, 4.2 g of DISPERBYK-110 and 4.2 g of wax to the blended resin solution, stir for 30 min to obtain a mixed slurry; The average particle size of the iron-silicon-chromium alloy powder is 8 μm; the solid content of the silicon aromatic acetylene resin solution is 50%; and the solid content of the silicone resin solution is 50%.

[0053] S2. Put the mixed slurry into a grinder and grind it at a speed of 60 r / min for 3 hours. During the grinding, 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 15 g.

[0054] S3, weigh 500g of absorbing paint and put it into a spray can, and spray it on the tinplate surface with a spray gun to obtain a high temperature resistant absorbing coating with a thickness of 1.5mm; when spraying, set the spray gun caliber to 1.5mm, the pressure to 0.7MPa, and the spray gun distance to 25cm; The high temperature resistant radar absorbing coating can be directly sprayed on the surface of a structural part, and the obtained radar absorbing coating has excellent temperature resistance and radar absorbing performance, and the coating is not easy to crack.

[0055] Example 3 S1. Mix 51.4 g of silanol resin solution and 154.28 g of organosilicon resin solution, and stir at a speed of 800 r / min for 30 min to obtain a blended resin solution. Under stirring conditions, add 420 g of carbonyl iron powder, 10 g of xylene, 4.2 g of DISPERBYK-110 and 4.2 g of wax to the blended resin solution, and stir for 30 min to obtain a mixed slurry; The average particle size of the carbonyl iron powder is 25 μm; the solid content of the silanol resin solution is 50%; and the solid content of the silicone resin solution is 50%.

[0056] S2. Put the mixed slurry into a grinder and grind it at a speed of 60 r / min for 3 hours. During the grinding, add xylene to the mixed slurry to adjust the viscosity of the mixed slurry to 30 Pa·s to obtain an absorbing coating; wherein, when adjusting the viscosity, the amount of xylene added is 20 g.

[0057] S3, weigh 500g of absorbing paint and put it into a spray can, and spray it on the tinplate surface with a spray gun to obtain a high temperature resistant absorbing coating with a thickness of 1.5mm; when spraying, set the spray gun caliber to 1.5mm, the pressure to 0.7MPa, and the spray gun distance to 25cm; The high temperature resistant radar absorbing coating can be directly sprayed on the surface of a structural part, and the obtained radar absorbing coating has excellent temperature resistance and radar absorbing performance, and the coating is not easy to crack.

[0058] Example 4 S1. Mix 120 g of silicon aryl acetylene resin solution and 660 g of organosilicon resin solution, stir at a speed of 800 r / min for 30 min to obtain a blended resin solution. Under stirring conditions, 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, stir for 30 min to obtain a mixed slurry; 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%.

[0059] S2. Put the mixed slurry into a grinder and grind it at a speed of 60 r / min for 3 hours. During the grinding, 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.

[0060] S3, weigh 500g of absorbing paint and put it into a spray can, and spray it on the tinplate surface with a spray gun to obtain a high temperature resistant absorbing coating with a thickness of 1.5mm; when spraying, set the spray gun caliber to 1.5mm, the pressure to 0.7MPa, and the spray gun distance to 25cm; The high temperature resistant radar absorbing coating can be directly sprayed on the surface of the structural parts, and the obtained radar absorbing coating has excellent heat resistance and radar absorbing performance, and the coating is not easy to crack; Comparative Example 1 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 alloy 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.

[0061] Comparative Example 2 Comparative Example 2 is the same as Example 2, except that: in step S1, 154.28 g of the silicone resin solution is 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 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.

[0062] Comparative Example 3 Comparative Example 3 is the same as Example 3, except that: in step S1, 154.28 g of the silicone resin solution is taken, 420 g of carbonyl iron 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.

[0063] Comparative Example 4 Comparative Example 4 is the same as Example 4, except that: in step S1, 660 g of the silicone resin solution is taken, 180 g of graphite microspheres, 5 g of xylene, 1.8 g of DISPERBYK-110 and 1.8 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.

[0064] In order to illustrate the performance of the radar absorbing coating provided by the present invention, a description is given in conjunction with the accompanying drawings.

[0065] The test performances of the silanylene 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.

[0066] Table 1 Test performance of silanol-modified silicone-based microwave absorbing coating and unmodified silicone-based microwave absorbing coating

[0067] As shown in Table 1, the adhesion, flexibility and impact resistance of the silicon aryl acetylene modified silicone resin-based absorbing coating and the unmodified silicone resin-based absorbing coating are similar at room temperature. After heat treatment at 350℃ / 48h, the adhesion, flexibility and impact resistance of the unmodified silicone resin-based absorbing coating are greatly attenuated, and the coating cracks and powders occur, while the adhesion, flexibility and impact resistance of the silicon aryl acetylene modified silicone resin-based absorbing coating are attenuated, but the coating is still intact without cracks and powders, indicating that the unmodified silicone resin-based absorbing coating is difficult to exist at 350℃ for a long time and its performance deteriorates. It further indicates that the unmodified silicone resin-based absorbing coating has poor temperature resistance without the silicon aryl acetylene resin solution blending modification.

[0068] Figure 1 The graphs are 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 coating provided in Example 1 of the present invention and Comparative Example 1 at room temperature and after heat treatment at 350°C / 48h.

[0069] like Figure 1 As shown, the silicon aryl yne modified silicone resin based absorbing coating provided in Example 1 and the unmodified silicone resin based absorbing coating provided in Comparative Example 1 are compared at room temperature with those after heat treatment at 350°C. The dielectric constant and magnetic permeability of the silicon aryl yne modified silicone resin based absorbing coating before and after heat treatment are similar, with little change, indicating that the silicon aryl yne modified silicone resin based absorbing coating can withstand 350°C and the absorbing performance is not deteriorated.

[0070] Figure 2 The graphs are 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 coating provided in Example 2 of the present invention and Comparative Example 2 at room temperature and after heat treatment at 350°C / 48h.

[0071] like Figure 2 As shown, the dielectric constant and magnetic permeability of the silicon aryl acetylene modified silicone resin-based absorbing coating provided in Example 2 and the unmodified silicone resin-based absorbing coating provided in Comparative Example 2 are similar before and after heat treatment at room temperature and at 350°C, with little change, indicating that the silicon aryl acetylene modified silicone resin-based absorbing coating can withstand 350°C and the absorbing performance is not deteriorated.

[0072] Figure 3The graphs are 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 coating provided in Example 3 of the present invention and Comparative Example 3 at room temperature and after heat treatment at 350°C / 48h.

[0073] like Figure 3 As shown, the dielectric constant and magnetic permeability of the silicon aryl acetylene modified silicone resin-based absorbing coating provided in Example 3 and the unmodified silicone resin-based absorbing coating provided in Comparative Example 3 are greatly different before and after heat treatment at room temperature and at 350°C. This is because the carbonyl iron powder is oxidized at high temperature.

[0074] Figure 4 The graphs are the real part (a) and imaginary part (b) of the dielectric constant of the high temperature resistant absorbing coating provided by Example 4 of the present invention and Comparative Example 4 at room temperature and after heat treatment at 350°C / 48h.

[0075] 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 before and after heat treatment at room temperature and change little, indicating that the silicon aryl yne modified silicone resin-based absorbing coating can withstand 350°C and the absorbing performance is not deteriorated.

[0076] Figure 5 This is the infrared spectrum of the product of the reaction of the silicone resin (organic silicon), the silylene 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 2200cm -1 There is an obvious absorption peak at 2100cm. Organic silicone resins such as methylphenyl silicone resin contain active hydrogen (-Si-H-) at 2100cm -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 an addition reaction to form a carbon-carbon double bond (-C=C-), proving that the two have reacted successfully.

[0077] In summary, the present invention provides a preparation and application of a silicon aryl acetylene modified resin-based high temperature resistant absorbing coating, the method comprising fully 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; under stirring conditions, adding a diluent to the mixed slurry to adjust the viscosity of the mixed slurry to obtain an absorbing coating; then spraying the absorbing coating on the surface of the substrate, curing in an oven, and obtaining a high temperature resistant absorbing coating. Under normal 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, and the silicon aryl acetylene resin is well dispersed between the absorbing coating matrix, so that the absorbing coating has excellent flexibility and impact resistance. As the temperature of the absorbing coating increases, intermolecular interactions and chemical bonds can be formed between the silicon aryl acetylene resin filler and the absorbing coating resin matrix, and there is a synergistic effect between the two, which can greatly 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".

[0078] Although 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 the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present 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 matrix resin is silicone resin, epoxy resin, polyamide resin or acrylic resin; The diluent is xylene, acetone, chloroform or tetrahydrofuran; The dispersant is DISPERBYK-110 dispersant; The anti-settling agent is wax.

2. The silicon aryl acetylene modified resin-based high temperature resistant radar absorbing coating according to claim 1, characterized in that: 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%.

3. The silicon aryl acetylene modified resin-based high temperature resistant radar absorbing coating according to claim 1, characterized in that: The particle size of the absorbent is 5 to 40 μm.

4. The silicon aryl acetylene modified resin-based high temperature resistant radar absorbing coating according to claim 1, characterized in that: The thickness of the radar absorbing coating is 0.5 to 2 mm.

5. A method for preparing the silicon aryl acetylene modified resin-based high temperature resistant radar absorbing coating according to any one of claims 1 to 4, 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.

6. The method for preparing the silicon aryl acetylene modified resin-based high temperature resistant radar absorbing coating according to claim 5, 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.

7. The method for preparing the silicon aryl acetylene modified resin-based high temperature resistant radar absorbing coating according to claim 5, 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.

8. The method for preparing the silicon aryl acetylene modified resin-based high temperature resistant radar absorbing coating according to claim 5, 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.

9. Use of the silicon aryl acetylene modified resin-based high temperature resistant wave absorbing coating according to any one of claims 1 to 4 in absorbing electromagnetic waves.

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