Super-hydrophobic anti-icing radome coating and preparation method thereof

Abstract

The application discloses a kind of super-hydrophobic anti-icing radome coating and preparation method thereof, the super-hydrophobic anti-icing radome coating includes micro-nano super-hydrophobic powder, modified fluorocarbon resin, trifluoro propyl methyl cyclotrisiloxane, solvent, curing agent and pigment;The micro-nano super-hydrophobic powder is prepared by the following steps: inorganic micro-nano powder is dispersed in mixed solvent, then water-oil double-solvent treatment agent is added to mix contact, finally, fraction, washing, drying, grinding, high-temperature curing, and the nano super-hydrophobic powder is obtained.The coating is about 80% less than conventional fluorocarbon resin coating at-10 ℃ The amount of ice, the ice melting speed is about 10 minutes faster.The dielectric constant of the coating is about 3.8, and the electrical performance test meets the technical requirements of civil aviation radome;After xenon lamp aging test for 500 hours, the coating still has good super-hydrophobic property and anti-icing performance, and has wide application.

Description

Technical Field

[0001] This invention relates to the technical field of radome coating materials, specifically to a superhydrophobic anti-icing radome coating and its preparation method. Background Technology

[0002] In modern air traffic control, radar control is a crucial tool for controllers. Multiple radar coverages are necessary to ensure signal stability and continuity, requiring the construction of radar stations in various locations. During winter or rainy weather, the radome surface of these radar stations may become icy or covered by rain film. This significantly reduces antenna efficiency, decreases the coverage area, and increases noise and temperature, thus affecting communication signal quality. Therefore, improving the anti-icing performance of radomes is essential to enhance radar operational stability and ensure civil aviation safety. Due to historical reasons, many navigation and related antenna products in my country did not consider the impact of icing during manufacturing. After years of use, some antenna radomes have aged or corroded severely. Antennas deployed in freezing environments are particularly vulnerable to icing and urgently require maintenance to extend their service life and ensure the safety of civil aviation operations.

[0003] Patent No. 202211130260 discloses a superhydrophobic glass microsphere and its preparation method and a superhydrophobic coating and its preparation method. The coating prepared by the method was tested and its electrical performance data exceeded the technical specifications of the radome, so it could not be used.

[0004] Although many studies have shown that superhydrophobic coatings have good anti-icing properties, most of them suffer from poor coating adhesion, or the powder used, although insulating, does not meet the technical specifications of the radome, requiring further research. Summary of the Invention

[0005] Purpose of the invention: In view of the shortcomings of the prior art, the purpose of this invention is to overcome the problems of poor adhesion of superhydrophobic materials, easy surface cracking, or the need for specific spraying processes in the prior art, and to solve the problem of small maintenance window for airport navigation antennas at night. The invention provides a superhydrophobic anti-icing antenna cover coating and its preparation method.

[0006] The method has a simple preparation process and can be scaled up industrially. The resulting superhydrophobic and anti-icing radome coating can be sprayed onto the radome to quickly obtain a superhydrophobic coating with a water contact angle greater than 150°. The coating surface is smooth and has good scratch resistance.

[0007] Technical solution:

[0008] To achieve the above objectives, the present invention provides a superhydrophobic anti-icing radome coating, wherein the superhydrophobic anti-icing radome coating comprises micro-nano superhydrophobic powder, modified fluorocarbon resin, trifluoropropylmethylcyclotrisiloxane, solvent, curing agent and pigment.

[0009] The micro-nano superhydrophobic powder is prepared by the following steps: dispersing inorganic micro-nano powder in a mixed solvent, then adding a water-oil dual-repellent agent and triethylamine for mixing and contact, and finally distilling, washing, drying, grinding and high-temperature curing to obtain the nano superhydrophobic powder.

[0010] The modified fluorocarbon resin is prepared by polymerization of quaternary ammonium salt fluorinated acrylate, methyl methacrylate and methacrylamide;

[0011] The quaternary ammonium salt fluorinated acrylate has the structure shown in Formula A:

[0012]

[0013] Furthermore, the solvent is butyl acetate.

[0014] Furthermore, the modified fluorocarbon resin is prepared by the following steps:

[0015] (1) In a reactor, add dimethylaminoethyl acrylate, perfluorohexyl propylene oxide, sodium hydroxide and anhydrous ethanol, heat to 50-60℃ and reflux for 3-4 hours, cool to crystallize, filter and dry to obtain quaternary ammonium salt fluorinated acrylate.

[0016] (2) In a reactor, quaternary ammonium salt fluorinated acrylate, methyl methacrylate and methacrylamide are added, heated to 70-80°C, and an initiator is added to react for 3-4 hours. After cooling, filtering and drying, the modified fluorocarbon resin is obtained.

[0017] Further, in step (1), the mass ratio of dimethylaminoethyl acrylate, perfluorohexyl propylene oxide and sodium hydroxide is (6-8):(18-21):(2-3);

[0018] In step (2), the initiator is selected from either azobisisobutyronitrile or azobisisoheptanenitrile;

[0019] In step (2), the mass ratio of quaternary ammonium salt fluorinated acrylate, methyl methacrylate and methacrylamide is (6-8):(3-5):(2-4).

[0020] Furthermore, the inorganic micro / nano powder is selected from at least one of nano-silica, pretreated boron nitride powder, or potassium titanate whiskers;

[0021] The water-oil dual-repellent agent is selected from at least one of tetraethoxysilane, fluoroalkyltrimethoxysilane or fluoroalkyltriethoxysilane;

[0022] The mass ratio of the inorganic micro / nano powder, the water-oil bihydrophobic agent, and triethylamine is 1:(0.4-1.0):(0.1-0.3).

[0023] Furthermore, the particle size of the nano-silica is 10-300 nm; the particle size of the pretreated boron nitride powder is 0.1-10 μm; and the potassium titanate whiskers are insulating potassium titanate whiskers.

[0024] The pretreated boron nitride powder is obtained by ball milling boron nitride at a speed of 80-120 r / min for 20-24 hours;

[0025] The mixed solvent is prepared by mixing an organic solvent with water, wherein the organic solvent is selected from at least one of ethanol or isopropanol.

[0026] Furthermore, the inorganic micro / nano powder comprises nano-silica, pretreated boron nitride powder, and potassium titanate whiskers in a mass ratio of (0.8-1.2):(1.8-2.2):(0.1-0.3).

[0027] When the amount of nano-silica exceeds the upper limit, the risk of cracking on the coating surface increases and the adhesion decreases; when the amount of nano-silica exceeds the lower limit, the risk of cracking on the coating surface decreases, but the roll-off angle of water droplets increases, affecting the hydrophobic properties; when the amount of nano-potassium titanate whiskers exceeds the upper limit, the coating surface becomes rougher, the adhesion decreases, and the roll-off angle of water droplets increases, affecting the hydrophobic properties; when the amount of nano-potassium titanate whiskers exceeds the lower limit, the risk of cracking on the coating surface increases.

[0028] Furthermore, the superhydrophobic anti-icing radome coating also contains perfluorosilanes and fluorinated surfactants.

[0029] Further, by weight, the superhydrophobic anti-icing radome coating comprises 2-4 parts of micro-nano superhydrophobic powder, 2-6 parts of modified fluorocarbon resin, 0.1-0.6 parts of trifluoropropylmethylcyclotrisiloxane, 0.1-0.6 parts of perfluorosilane, 0.1-0.6 parts of fluorinated surfactant, 15-25 parts of solvent, 0.5-1.2 parts of curing agent, and 0.1-0.8 parts of pigment.

[0030] Furthermore, in the preparation of the micro-nano superhydrophobic powder, the mixing and contact temperature is 20-60℃, and the mixing and contact time is 1-15h; the high-temperature curing temperature is greater than 140℃, and the time is greater than 10 minutes.

[0031] The preparation method of any of the above-mentioned superhydrophobic anti-icing radome coatings includes the following steps:

[0032] (1) Disperse the micro-nano superhydrophobic powder in a solvent, and then add modified fluorocarbon resin, trifluoropropylmethylcyclotrisiloxane, perfluorosilane and fluorinated surfactant to obtain a mixture;

[0033] (2) The superhydrophobic anti-icing radome coating is prepared by adding curing agent and pigment to the mixture.

[0034] Beneficial effects:

[0035] 1. The superhydrophobic composite powder in this invention uses industrially available boron nitride, potassium titanate whiskers, silicon dioxide, and pigments as raw materials. This not only saves on formulation costs but also creates a lotus leaf effect in the superhydrophobic material after coating treatment. When the superhydrophobic composite powder is applied to prepare superhydrophobic coatings, the resulting superhydrophobic coating exhibits excellent superhydrophobic properties, with a water contact angle greater than 150° and good self-cleaning function.

[0036] 2. The boron nitride powder used in this invention has good insulation and thermal conductivity, excellent electrical performance indicators, and a relatively fast ice melting speed, which can greatly improve the ability of navigation equipment to cope with extreme climates.

[0037] 3. The modified fluorocarbon resin prepared by copolymerizing quaternary ammonium salt fluorinated acrylate, methyl methacrylate and methacrylamide in this invention has the following advantages: First, by polymerizing quaternary ammonium salt fluorinated acrylate in the resin structure, the fluorinated groups can not only significantly improve the hydrophobicity of the coating, but also enhance the weather resistance of the coating and expand its application range. Second, the quaternary ammonium structure in the quaternary ammonium salt fluorinated acrylate can further improve the surface activity of the fluorocarbon resin, thereby improving the hydrophobicity of the coating.

[0038] 4. The superhydrophobic coating prepared by the method described in this invention, after final curing, not only has excellent superhydrophobic properties, but also excellent wear resistance and scratch resistance. The superhydrophobic properties of the coating are not affected before and after sanding and scratching, and the superhydrophobic properties of the coating are very stable.

[0039] 5. The anti-icing coating of the present invention has a simple construction process and can quickly achieve superhydrophobic properties, which is suitable for the short maintenance window of airport navigation equipment.

[0040] 6. The preparation method of this invention is simple and easy to implement, without the need for high temperature and high pressure and multi-step reaction, and the raw materials are cheap and readily available. It can be scaled up industrially and has great industrialization prospects. Moreover, the superhydrophobic coating obtained after industrial scale-up experiments still has good superhydrophobic properties, successfully overcoming the defects existing in the prior art. Attached Figure Description

[0041] Figure 1 This is a block diagram of the electrical performance testing system for radome components.

[0042] Figure 2 This is a curve showing the insertion loss of the material as a function of frequency in an embodiment of the present invention.

[0043] Figure 3 The curve shows the insertion loss of the comparative material of this invention as a function of frequency.

[0044] Figure 4 This is the insertion loss curve of the honeycomb panel material as a function of frequency.

[0045] Figure 5 This is a rain test diagram.

[0046] Figure 6 and Figure 7 The image shows the hydrophobic properties of the material after xenon lamp aging, as an example.

[0047] Figure 8 and Figure 9 This is a test image showing the anti-icing properties of the material of this invention.

[0048] Figure 5 , Figure 8 , Figure 9 In the examples of this application, “Test Sample M750-M5# Anti-icing Superhydrophobic Coating” refers to the anti-icing superhydrophobic coating sample, and “Comparative Sample Fluorocarbon Coating” refers to the product of the comparative example of this application. Detailed Implementation

[0049] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0050] The perfluorosilane is heptadecafluorodecyltrimethoxysilane; the fluorinated surfactant is sodium perfluorononenoxybenzenesulfonate; the curing agent is ethylenediamine; the pigment is nano-titanium dioxide; and the remaining reagents and equipment are conventional reagents and equipment in this technical field.

[0051] Preparation of modified fluorocarbon resin

[0052] Modified fluorocarbon resin was prepared by the following steps:

[0053] (1) 0.3g of dimethylaminoethyl acrylate, 0.9g of perfluorohexyl propylene oxide, 0.1g of sodium hydroxide and 50mL of anhydrous ethanol were added to a 250mL four-necked flask equipped with a spherical condenser, mechanical stirrer, thermometer and hollow stopper. After heating to 60℃ and refluxing for 4 hours, the quaternary ammonium salt fluorinated acrylate was obtained by cooling, crystallization, filtration and drying.

[0054] (2) In a reactor, 3g of quaternary ammonium salt fluorinated acrylate, 2g of methyl methacrylate and 1g of methacrylamide were added, heated to 75°C, and 0.1g of azobisisobutyronitrile was added and reacted for 3 hours. After cooling, filtering and drying, the modified fluorocarbon resin was obtained.

[0055] Example

[0056] 1. Micro / nano superhydrophobic powders were prepared by the following steps:

[0057] By weight, 1 part of inorganic micro / nano powder is dispersed in 20 parts of mixed solvent, then 0.5 parts of fluorinated alkyltrimethoxysilane and 0.2 parts of triethylamine are added and mixed at 50°C for 3 hours. Finally, the mixture is distilled, washed, dried, ground, and cured at 200°C for 20 minutes to obtain nano-superhydrophobic powder.

[0058] The inorganic micro / nano powders include nano-silica with a particle size of 15 nm, pretreated boron nitride powder with a particle size of 500 nm, and potassium titanate whiskers in a mass ratio of 1:2:0.2.

[0059] The pretreated boron nitride powder was obtained by ball milling boron nitride at a speed of 100 r / min for 24 hours;

[0060] The mixed solvent comprises isopropanol, ethanol, and water in a mass ratio of 15:0.1:1.

[0061] 2. Preparation of superhydrophobic anti-icing radome coating by the following steps: by weight parts,

[0062] (1) Disperse 3 parts of micro-nano superhydrophobic powder in 20 parts of butyl acetate, then add 5 parts of modified fluorocarbon resin, 0.3 parts of trifluoropropylmethylcyclotrisiloxane, 0.3 parts of perfluorosilane and 0.25 parts of fluorinated surfactant to obtain a mixture;

[0063] (2) The superhydrophobic anti-icing radome coating is prepared by adding 0.7 parts of curing agent and 0.7 parts of pigment to the mixture.

[0064] Comparative Example

[0065] The coating is prepared by the following steps: by weight parts,

[0066] (1) Disperse 3 parts of glass microspheres in 10 parts of butyl acetate, 15 parts of ethanol and 1 part of water, then add 1 part of perfluorosilane, 3 parts of triethylamine and 3.5 parts of epoxy resin to obtain a mixture;

[0067] (2) Add 0.7 parts of curing agent to the mixture to obtain the coating.

[0068] Performance testing

[0069] 1. Electrical performance testing:

[0070] In a microwave anechoic chamber, a vector network analyzer (model: MS46322A) and a double-ridged horn antenna (model: HD-10180DRHA10S) were used, and... Figure 1 The antenna test system is connected as shown and powered on for preheating. The auxiliary antenna is used for transmitting, and the antenna under test is used for receiving. The distance between the two antennas meets the far-field test requirements, i.e., d > 2D. 2 / λ, d is the distance between the transmitting and receiving antennas, D is the aperture of the antenna under test, λ is the operating wavelength, the two antennas are erected at the same height and have the same polarization.

[0071] The speaker model is HD-10180DRHA10S, with an operating frequency of 1~18GHz, a gain of 7~13dB, a beamwidth of 30~80°, and an aperture size of 284mm*160mm. Based on the actual test environment and far-field test requirements, the distance d between the transmitting and receiving antennas is 5 meters, and the speaker height is 1 meter above the ground.

[0072] Select the network analyzer's operating mode as frequency sweep test mode, set the target test parameter to S21 amplitude (i.e., port 1 transmits the signal, port 2 receives the signal), and set the starting frequency f. START and termination frequency f STOP The operating frequency of the radome unit under test is [f1, f2]. Set f... START <f1,f STOP >f2. After the instrument settings are complete and the system is stable, perform system calibration by storing the received frequency sweep test data into the instrument register. While keeping all instrument settings unchanged, place the radome unit under test between the transmitting and receiving antennas, close to the receiving antenna, at a distance of 0.5–1 m (adjust the position within this range to reduce spatial standing waves caused by the radome unit). Note: Do not move the initial position of the antennas when setting up the radome unit. Compare the test data after adding the radome unit with the data in the register (the instrument has this function and performs it automatically). The resulting amplitude curve (in dB) is the insertion loss curve of the radome unit as a function of frequency.

[0073] After testing, the insertion loss curve of the material in the example as a function of frequency is shown below. Figure 2 The insertion loss curve of the comparative material as a function of frequency is shown below. Figure 3 The insertion loss curve of the honeycomb panel material as a function of frequency is as follows: Figure 4 ;

[0074] The following is a statistical table of electrical performance test results:

[0075]

[0076] 2. Rain test:

[0077] Rain test results are as follows Figure 5 As shown. After rain testing, the anti-icing superhydrophobic coating sample in this embodiment of the invention has good hydrophobicity, and no water film forms on the coating surface; while the comparative material has a large number of water droplets accumulating on its surface.

[0078] 3. Dielectric constant test:

[0079] According to SGS testing, the dielectric constant of the anti-icing superhydrophobic coating sample in this embodiment of the invention is approximately 3.83.

[0080] 4. Aging performance test:

[0081] like Figure 6 and Figure 7 As shown, after 500 hours of xenon lamp aging test, the anti-icing superhydrophobic coating sample in the embodiment still exhibits good superhydrophobic properties.

[0082] 5. Anti-icing and de-icing tests:

[0083] Place the coating with anti-icing coating in a constant temperature freezer for more than 24 hours, then spray a mixture of water and ice at close to 0°C onto the coating surface, and observe and record the icing situation.

[0084] like Figure 8 and Figure 9 As shown, at -10°C, the anti-icing superhydrophobic coating of the present invention reduces the amount of ice formation by about 80% compared with conventional polytetrafluoroethylene coatings, and the melting speed is about 10 minutes faster; however, at a low temperature of -20°C, the formation rate of ice crystals is accelerated, and the anti-icing ability is not outstanding.

[0085] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A superhydrophobic anti-icing radome coating, characterized in that, By weight, the superhydrophobic anti-icing radome coating comprises 2-4 parts of micro-nano superhydrophobic powder, 2-6 parts of modified fluorocarbon resin, 0.1-0.6 parts of trifluoropropylmethylcyclotrisiloxane, 0.1-0.6 parts of perfluorosilane, 0.1-0.6 parts of fluorinated surfactant, 15-25 parts of solvent, 0.5-1.2 parts of curing agent, and 0.1-0.8 parts of pigment; The micro-nano superhydrophobic powder is prepared by the following steps: dispersing inorganic micro-nano powder in a mixed solvent, then adding a water-oil dual-repellent agent and triethylamine for mixing and contact, and finally distilling, washing, drying, grinding and high-temperature curing to obtain the micro-nano superhydrophobic powder. The modified fluorocarbon resin is prepared by polymerization of quaternary ammonium salt fluorinated acrylate, methyl methacrylate and methacrylamide; The mass ratio of the quaternary ammonium salt fluorinated acrylate, methyl methacrylate and methacrylamide is (6-8):(3-5):(2-4); The quaternary ammonium salt fluorinated acrylate has the structure shown in Formula A: ； The inorganic micro / nano powder comprises nano-silica, pretreated boron nitride powder, and potassium titanate whiskers in a mass ratio of (0.8-1.2):(1.8-2.2):(0.1-0.3).

2. The superhydrophobic anti-icing radome coating according to claim 1, characterized in that, The modified fluorocarbon resin is prepared by the following steps: (1) In a reactor, add dimethylaminoethyl acrylate, perfluorohexyl propylene oxide, sodium hydroxide and anhydrous ethanol, heat to 50-60℃ and reflux for 3-4 hours, cool to crystallize, filter and dry to obtain quaternary ammonium salt fluorinated acrylate. (2) In a reactor, quaternary ammonium salt fluorinated acrylate, methyl methacrylate and methacrylamide are added, heated to 70-80°C, and an initiator is added to react for 3-4 hours. After cooling, filtering and drying, the modified fluorocarbon resin is obtained.

3. The superhydrophobic anti-icing radome coating according to claim 2, characterized in that, In step (1), the mass ratio of dimethylaminoethyl acrylate, perfluorohexyl propylene oxide, and sodium hydroxide is (6-8):(18-21):(2-3). In step (2), the initiator is selected from either azobisisobutyronitrile or azobisisoheptanenitrile.

4. The superhydrophobic anti-icing radome coating according to claim 1, characterized in that, The water-oil dual-repellent agent is selected from at least one of tetraethoxysilane, fluoroalkyltrimethoxysilane, or fluoroalkyltriethoxysilane; The mass ratio of the inorganic micro / nano powder, the water-oil bihydrophobic agent, and triethylamine is 1:(0.4-1.0):(0.1-0.3).

5. The superhydrophobic anti-icing radome coating according to claim 1, characterized in that, The nano-silica has a particle size of 10-300 nm; the pretreated boron nitride powder has a particle size of 0.1-10 μm; and the potassium titanate whiskers are insulating potassium titanate whiskers. The pretreated boron nitride powder is obtained by ball milling boron nitride at a speed of 80-120 r / min for 20-24 hours; The mixed solvent is prepared by mixing an organic solvent with water, wherein the organic solvent is selected from at least one of ethanol or isopropanol.

6. The superhydrophobic anti-icing radome coating according to claim 1, characterized in that, In the preparation of the micro-nano superhydrophobic powder, the mixing and contact temperature is 20-60℃, and the mixing and contact time is 1-15h; the high-temperature curing temperature is greater than 140℃, and the time is greater than 10 minutes.

7. The method for preparing the superhydrophobic anti-icing radome coating according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Disperse the micro-nano superhydrophobic powder in a solvent, and then add modified fluorocarbon resin, trifluoropropylmethylcyclotrisiloxane, perfluorosilane and fluorinated surfactant to obtain a mixture; (2) The superhydrophobic anti-icing radome coating is prepared by adding curing agent and pigment to the mixture.

Images