Low-glossiness, corrosion-resistant and low-infrared-emissivity filler and infrared stealth coating

Abstract

The invention relates to a filler with low glossiness, corrosion resistance and low infrared emissivity and an infrared stealth coating. The low-infrared-emissivity filler is prepared from the following raw material components in parts by mass: 20-40 parts of Cu powder, 5-15 parts of Al powder, 2-5 parts of matting powder, 1-2 parts of a first additive, 1-2 parts of a second additive and 1-12 parts of a coupling agent. The infrared stealth coating is prepared from the following raw material components in parts by mass: 2-4 parts of low-infrared-emissivity filler, 2-4 parts of a resin matrix, 2.5-3.5 parts of a curing agent and 2-15 parts of an organic solvent. Compared with the prior art, the filler and the infrared stealth coating with low infrared emissivity, low glossiness and corrosion resistance are prepared.

Description

Technical Field

[0001] The invention belongs to the technical field of coatings, and in particular relates to a low-gloss, corrosion-resistant, low-infrared emissivity filler and an infrared stealth coating. Background Art

[0002] The use of metal pigments and fillers represented by Al powder is still a commonly used technical means for low-emissivity coatings at home and abroad. In particular, flaky aluminum powder is one of the most important fillers for reducing the infrared emissivity of coatings. Because this form of Al powder is light and floating, this low-emissivity coating has a glittering appearance, which is difficult to blend with the background and is not conducive to visible light invisibility. In addition, Al powder itself easily reacts with oxygen to form an aluminum oxide film, which provides a certain degree of protection. However, in harsh environments (such as high humidity, salt spray, etc.), the oxide film may be destroyed, leading to corrosion; and the larger surface area of ​​flaky aluminum powder also increases the risk of corrosion. In actual use, the coating cannot be separated from complex environments such as acid rain and heavy fog. It is of great significance to study and solve the corrosion resistance of low-infrared emissivity coatings and obtain low-emissivity coatings with stable performance in corrosive environments.

[0003] Commonly used matting agents such as silica and titanium dioxide have a large pore volume and a uniform particle size distribution, with the particle size and dry film thickness being well matched. They offer excellent matting properties and are readily available and inexpensive. However, the addition of such matting agents increases the infrared emissivity of the coating, making compatibility difficult. Another method for coating matting that has been widely studied in recent years is the use of matting resins. Low-gloss resins are obtained by mixing or modifying multiple resins. The matting mechanism primarily utilizes the different curing temperatures of the resin and curing agent, causing uneven shrinkage of the coating surface and producing a matting effect. Furthermore, certain monomers that are incompatible with the resin are introduced into the resin. During the film-forming process, the monomers precipitate, creating microscopic roughness and thus achieving low gloss. However, these methods present practical application challenges such as a complex preparation process and unstable coating and coating properties.

[0004] CN117720831A discloses a low-gloss, low-infrared emissivity pigment and filler, as well as its preparation and testing methods. The pigment comprises the following raw materials, calculated by mass: 40-50% flake-leafing aluminum powder, 50-60% phthalocyanine blue powder, and 0.25-0.35% silane coupling agent. This technical solution uses phthalocyanine blue powder to mask the metallic luster of the aluminum powder, achieving a low gloss, deep-sea blue color, and low infrared emissivity. However, the combination of flake-leafing aluminum powder and phthalocyanine blue powder still fails to improve the corrosion resistance of the coating.

[0005] Therefore, it is urgent to develop a new filler and infrared stealth coating that has low gloss, corrosion resistance and low infrared emissivity. Summary of the Invention

[0006] The purpose of the present invention is to provide a low-gloss, corrosion-resistant, low-infrared emissivity filler and infrared stealth coating in order to overcome the defects of the prior art that it is difficult to achieve low gloss, corrosion resistance and low infrared emissivity.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] The present invention first provides a low-gloss, corrosion-resistant, low-infrared emissivity filler, which is prepared from the following raw material components in parts by weight: 20-40 parts of Cu powder, 5-15 parts of Al powder, 2-5 parts of matting powder, 1-2 parts of a first additive, 1-2 parts of a second additive, and 1-12 parts of a coupling agent;

[0009] The first additive includes one or more of stearic acid, palmitic acid, oleic acid, and citric acid;

[0010] The second additive includes one or more of glycine, p-aminobenzoic acid, and β-alanine;

[0011] The matting powder includes one or more of bronze powder, nano titanium dioxide, and fumed silica, preferably bronze powder.

[0012] Furthermore, the coupling agent includes one or more of an aminosilane coupling agent, an epoxysilane coupling agent, a methacryloxysilane coupling agent, and a mercaptosilane coupling agent, preferably silane coupling agent KH-550.

[0013] Furthermore, the low infrared emissivity filler is prepared from the following raw material components in parts by mass: 20 parts of Cu powder, 10 parts of Al powder, 1 part of matting powder, 1-2 parts of the first additive, 1-2 parts of the second additive, and 1-12 parts of a coupling agent.

[0014] Furthermore, the particle size of the Cu powder is 10-25 μm.

[0015] Furthermore, the particle size of the Al powder is 10-25 μm.

[0016] Furthermore, the average particle size of the low infrared emissivity filler is 10-25 μm.

[0017] Furthermore, the low infrared emissivity filler has an aspect ratio of 50-500.

[0018] Furthermore, the Cu powder is prepared by the following method:

[0019] S1: heating an aqueous solution containing copper salt, alkali and glucose under alkaline conditions, and separating the supernatant containing Cu2O after standing;

[0020] S2: adding an anti-settling agent, NH4Cl and a reducing agent to the upper clear liquid, and performing a reduction reaction in a protective gas atmosphere to obtain the Cu powder.

[0021] Furthermore, in step S1, the mass ratio of the copper salt, the base and the glucose is (1.2-1.8):1:(2-3).

[0022] Furthermore, in step S1, the heating temperature is 75-85° C., and the heating time is 0.5-1.5 h.

[0023] Furthermore, in step S2, the anti-precipitation agent is polyvinyl pyrrolidone, and the mass ratio of the anti-precipitation agent to Cu2O is 1:(45-60).

[0024] Furthermore, in step S2, the molar ratio of NH4Cl to Cu2O is (0.2-0.5):1.

[0025] Furthermore, in step S2, the reducing agent is hydrazine hydrate, and the mass ratio of hydrazine hydrate to Cu2O is (2.2-2.8):1.

[0026] Furthermore, in step S2, the temperature of the reduction reaction is 75-85° C., and the time of the reduction reaction is 4-8 hours.

[0027] Furthermore, the low infrared emissivity filler is prepared by the following method: Cu powder, Al powder, matting powder, a first additive and a second additive are weighed and mixed in proportion, followed by ball milling, filtering and drying to obtain floating Al-Cu powder; the floating Al-Cu powder is dispersed in an organic solvent and a coupling agent is added to react, and the low infrared emissivity filler is obtained by filtering and drying.

[0028] Furthermore, the ball-to-material ratio of the ball mill is (5-15):1, the ball milling time is 4-8 hours, and the ball milling speed is 300-400 rpm.

[0029] The present invention also provides an infrared stealth coating comprising a low infrared emissivity filler. The infrared stealth coating is prepared from the following raw material components in parts by mass: 1.2-1.5 parts of a low infrared emissivity filler, 0.52-4.9 parts of a resin matrix, 0.32-2.4 parts of a curing agent, and 2-15 parts of an organic solvent.

[0030] Furthermore, the infrared stealth coating is prepared from the following raw material components in parts by mass: 2-4 parts of low infrared emissivity filler, 2-4 parts of resin matrix, 2.5-3.5 parts of curing agent, and 2-15 parts of organic solvent.

[0031] Furthermore, the resin matrix includes one or more of polyurethane resin, epoxy-modified polyurethane resin, and modified acrylic resin.

[0032] Furthermore, the curing agent includes one or more of an isocyanate curing agent, an aliphatic curing agent, and a polyol curing agent.

[0033] Furthermore, the organic solvent includes one or more of butyl acetate, acetone, xylene, ethanol, and isopropanol.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The present invention adds a matting agent to Cu powder and Al powder and performs mixed ball milling to matt the powder. At the same time, the Al and Cu powders are modified by interface modification technology. The matting effect and corrosion resistance are greatly improved while maintaining the low emissivity of the coating. A filler and an infrared stealth coating with low infrared emissivity, low gloss and corrosion resistance are successfully prepared.

[0036] (2) The present invention uses mixed ball milling to cause the -OH groups of the Al-Cu powder to undergo a condensation reaction with the -COOH in the first additive, so that the Cu powder has polar groups, and the carboxyl groups of the second additive can be directionally adsorbed on the powder surface, so that the Al-Cu powder has floating properties.

[0037] (3) The present invention uses a coupling agent to modify the surface of Al and Cu powders, improving the interface between the polymer and the filler. The addition of a coupling agent to the Cu powder further enhances the density of the composite coating system, significantly reducing the porosity compared to the unmodified coating. This in turn reduces the permeation rate of corrosive ions, effectively slowing the corrosion of the coating by corrosive factors. This results in the resulting coating possessing environmental and aging resistance properties.

[0038] (4) The floating filler prepared by the present invention has leaf-spreading characteristics. As the solvent in the coating evaporates, its molecules move toward the air surface, driving the light-weight powder flakes to float to the air surface. Numerous flaky Al-Cu powders are connected to each other, and the gaps between large and small particles and between layers are filled to form a continuous, dense, and basically pore-free metal film. Therefore, it has the characteristics of high reflection and low absorption of infrared radiation and has a very low infrared emissivity.

[0039] (5) The preparation method of the filler and infrared stealth coating of the present invention has the advantages of simple process, low cost, high output and low requirement for synthesis equipment, and can be produced on a large scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is the infrared transmittance spectrum of the infrared filler of Example 1 of the present invention before and after ball milling.

[0041] Figure 2 1 is an infrared spectrum of the filler powder of Example 1 of the present invention before and after coupling modification.

[0042] Figure 3 These are SEM images of the filler powder of Example 1 of the present invention before and after coupling modification.

[0043] Figure 4 This is the SEM image of the infrared stealth coating of Example 1 of the present invention.

[0044] Figure 5 This is a test data chart of the infrared emissivity of the coatings of Examples 1-3 of the present invention and Comparative Example 1.

[0045] Figure 6 This is a glossiness test data diagram of Example 1 and Comparative Example 2 of the present invention.

[0046] Figure 7 Graph showing the infrared emissivity of Examples 1, 4-6 and Comparative Examples 3-4 versus corrosion time. DETAILED DESCRIPTION

[0047] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0048] Unless otherwise specified, the reagents, methods, instruments, and equipment used in this invention are conventional in the art. Unless otherwise specified, the reagents and materials used in the following examples were commercially available. Specifically, bronze powder was used as the matting agent; stearic acid was used as the first additive; aminoacetic acid was used as the second additive; KH550 was used as the coupling agent; polyurethane resin was used as the resin matrix; and N-75 was used as the curing agent.

[0049] Example 1:

[0050] This embodiment provides a low-gloss, corrosion-resistant, low-infrared emissivity filler and an infrared stealth coating containing the filler. The preparation method of the low-infrared emissivity filler is as follows:

[0051] (1) 850 mL of water containing 40 g CuSO4, 27 g NaOH and 60 g C6H 12 The aqueous solution of O6 was heated at 80°C for 1 hour to prepare a Cu2O solution, which was allowed to stand and then the supernatant was decanted.

[0052] (2) The obtained Cu2O was transferred to a 500mL four-necked flask and 100mL of deionized water was added to form a turbid solution of Cu2O. 10mL of PVP was added and NH4Cl was added at a molar ratio of NH4Cl:Cu2O=0.5:1. Nitrogen was then introduced and the temperature was raised to 80°C.

[0053] (3) Slowly add 65 g of 10% hydrazine hydrate dropwise, and the reaction ends after 6 hours.

[0054] (4) The obtained Cu powder was centrifugally washed 5 times with deionized water and then 2 times with anhydrous ethanol. The generated Cu powder was placed in oleic acid for storage.

[0055] (5) 10 g of Cu powder, 5 g of Al powder, 1.5 g of matting powder, 0.5 g of the first additive, and 0.5 g of the second additive were weighed and mixed, and then ball-milled at 350 rpm for 6 h under zirconia balls (ball-to-material ratio of 10:1), and then filtered and dried to obtain Al-Cu powder.

[0056] (6) 10 g of Al-Cu powder was weighed and added to 100 mL of acetone and pre-dispersed using ultrasonication. A total of 1.0 g of coupling agent KH550 was then added dropwise and treated with ultrasonication. The mixture was then filtered, washed with acetone, and vacuum-dried to obtain a low infrared emissivity filler, which was subsequently designated AC-K.

[0057] Based on the prepared low-gloss, corrosion-resistant, low-infrared emissivity filler, the preparation method of the infrared stealth coating of this embodiment is as follows:

[0058] (1) 3.55 g of polyurethane resin was weighed and dissolved in 10 mL of butyl acetate solution. The mixture was stirred and ultrasonically defoamed. 4 g of AC-K filler was added and dispersed evenly. 2.9 g of curing agent N-75 was added and solvent was added to adjust the viscosity.

[0059] (2) Using manual spraying technology, the spray gun pressure is 0.3-0.5 MPa, the nozzle diameter is 1.5 mm, and the spraying distance is controlled at 20-25 cm. It is sprayed on the treated substrate and then cured at 80 ° C for 3 h to obtain an infrared stealth coating, which is recorded as PU / AC1.

[0060] Figure 1 The infrared transmittance spectra of the infrared filler of this embodiment before and after ball milling are shown in Figure (a). Figure (b) and Figure (c) are the infrared transmittance spectra of the first additive and the second additive, respectively. Figure (d) is the infrared transmittance spectra of the filler powder after ball milling. As shown in Figure (a), the infrared transmittance of the Al-Cu powder before ball milling is 3467cm -1 and 1637cm -1 There is an -OH group at the bottom of the powder. Due to the condensation reaction between -OH and -COOH in the first additive, the Cu powder has a polar group, which can make the carboxyl group of the second additive directional adsorbed on the powder surface, and finally make the Al-Cu powder have floating characteristics. The floating Al-Cu powder is at 1585cm -1 and 1114cm -1There are characteristic peaks of C=O and CO at 2956cm -1 , 2916cm -1 , 2849cm -1 and 1466cm -1 The presence of a characteristic peak of CH at indicates that the first and second additives are coated on the Al-Cu powder. Without the addition of these two additives during filler preparation, the floatability of the Al-Cu powder cannot be achieved, which in turn affects the filler's low infrared emissivity performance.

[0061] Figure 2 The following are SEM images of the filler powder used in this example before and after modification with the silane coupling agent KH550. Figure (a) shows the SEM image of the unmodified filler powder, while Figure (b) shows the SEM image of the modified filler powder. It can be seen that the modified filler powder is flaky with a large aspect ratio of approximately 50-500. This makes it difficult to observe the coating of the silane coupling agent KH-550 on the powder surface, thus requiring further infrared testing.

[0062] Figure 3 The following are the infrared spectra of the filler powder before and after modification in this example. Curve (a) represents the FTIR spectrum of the filler powder without coupling agent modification, and curve (b) represents the FTIR spectrum of the filler powder after coupling agent modification. It can be seen that at 3467.50 cm -1 The presence of a sharp peak indicates the presence of -OH on the filler surface, which may be due to the partial oxidation of Cu powder exposed to air. -1 The NH bond bending vibration absorption peak of -NH2 appears at 1062.55cm -1 There is an absorption peak of Si-OM (M=Si, Cu) bond at , indicating that the silane coupling agent KH550 has been grafted to the filler surface through covalent bonds.

[0063] Figure 4 The following are SEM images of the infrared stealth coating of this embodiment. Figure (a) shows the SEM image of the coating made using unmodified filler powder, and Figure (b) shows the SEM image of the coating made using modified filler powder. It can be seen from the figure that the density of the composite coating system is further improved after the filler powder is modified by the coupling agent, and the porosity is significantly reduced compared to the unmodified coating. This may reduce the permeation rate of corrosive ions, thereby effectively slowing down the corrosion of the coating by corrosion factors; secondly, due to the improvement of the adhesion of the modified coating, after the coating is immersed in acid, alkali and salt solution, its attachment point does not move due to the relaxation of the coating, but remains fixed to the original attachment point, and the coating is not prone to blistering or falling off. Therefore, the coating can maintain its emissivity unchanged for a long time in the corrosive medium.

[0064] Floating fillers exhibit leaf-like properties. When mixed with a binder to form a coating, the solvent in the coating evaporates, causing its molecules to move toward the air surface. This kinetic energy is sufficient to propel the lightweight flakes to the surface. As the solvent evaporates, the numerous flaky Al-Cu powders connect with each other, filling the gaps between large and small particles and between layers, forming a continuous, dense metal film. Because the coating is dense and virtually porosity-free, it exhibits high reflectivity and low absorption of infrared radiation, resulting in very low emissivity. Furthermore, the significant reduction in porosity further reduces the transmission rate of corrosive ions, effectively slowing the corrosion of the coating by corrosive agents.

[0065] Example 2:

[0066] This embodiment provides a low-gloss, corrosion-resistant, low-infrared emissivity filler and an infrared stealth coating containing the filler. The difference from Example 1 is that in this embodiment, 3 g of AC-K filler is added to the polyurethane resin solution during the preparation of the infrared stealth coating.

[0067] Example 3:

[0068] This embodiment provides a low-gloss, corrosion-resistant, low-infrared emissivity filler and an infrared stealth coating containing the filler. The difference from Example 1 is that in this embodiment, 2 g of AC-K filler is added to the polyurethane resin solution during the preparation of the infrared stealth coating.

[0069] Example 4:

[0070] This example provides a low-gloss, corrosion-resistant, low-infrared emissivity filler and an infrared stealth coating containing the filler. The difference from Example 1 is that in this example, 2 g of KH550 is added during the preparation of the low-infrared emissivity filler. Other addition amounts and preparation methods are similar to those in Example 1.

[0071] Example 5:

[0072] This example provides a low-gloss, corrosion-resistant, low-infrared emissivity filler and an infrared stealth coating containing the filler. The difference from Example 1 is that this example uses 4 g of KH550 when preparing the low-infrared emissivity filler. Other addition amounts and preparation methods are similar to those in Example 1.

[0073] Example 6:

[0074] This example provides a low-gloss, corrosion-resistant, low-infrared emissivity filler and an infrared stealth coating containing the filler. The difference from Example 1 is that in this example, 6 g of KH550 is added to prepare the low-infrared emissivity filler. Other addition amounts and preparation methods are similar to those in Example 1.

[0075] Comparative Example 1:

[0076] This comparative example provides a filler and an infrared coating containing the filler. The difference from Example 1 is that in this comparative example, 1 g of AC-K filler is added to the polyurethane resin solution when preparing the infrared stealth coating. Other addition amounts and preparation methods are similar to those of Example 1.

[0077] Comparative Example 2:

[0078] This comparative example provides a filler and an infrared coating containing the filler. The difference from Example 1 is that bronze powder is not added when preparing the low infrared emissivity filler in this comparative example, and other addition amounts and preparation methods refer to Example 1.

[0079] Comparative Example 3:

[0080] This comparative example provides a filler and an infrared coating containing the filler. The difference from Example 1 is that KH550 is not added when preparing the low infrared emissivity filler in this comparative example, and other addition amounts and preparation methods refer to Example 1.

[0081] Comparative Example 4:

[0082] This comparative example provides a filler and an infrared coating containing the filler. The difference from Example 1 is that the amount of KH550 added in this comparative example when preparing the low infrared emissivity filler is 8g, and the other addition amounts and preparation methods are the same as those in Example 1.

[0083] The present invention performs the following tests on the infrared coatings obtained in the above-mentioned embodiments and comparative examples:

[0084] (1) Infrared emissivity test:

[0085] Test standards: emissivity range 0.05-1, temperature range 20-500°C, spectral range 8-14μm; uncertainty 0.02-0.07;

[0086] Test conditions: ambient temperature 20°C, ambient humidity 40% RH, test temperature 30°C;

[0087] Test equipment: 20-500℃ electric focus temperature measurement thermal imager;

[0088] Test method: Place the test sample on a heating platform, set the temperature, and wait for it to stabilize. Use an infrared camera to record the measured temperature of the test sample and a material of known emissivity. Calculate the true temperature of the material of known emissivity using a formula. Calculate the infrared emissivity of the test sample in the 8-14μm band based on its infrared temperature.

[0089] (2) Glossiness test:

[0090] Test standard: A three-angle gloss meter (such as 20°, 60°, and 85°) is an instrument that quantifies gloss by measuring the intensity of specular reflection from the paint film surface. The test principle is based on the law of specular reflection of light and the difference in gloss sensitivity at different angles.

[0091] Test conditions: ambient temperature: 20°C, ambient humidity: 40% RH;

[0092] Testing equipment: three-angle gloss meter;

[0093] Test method: Place the calibration sample under the glossmeter, completely covering the optical window. Connect the power cord, select the test angle, and rotate the knob to calibrate. After calibration, place the sample to be tested under the glossmeter, completely covering the optical window. The value displayed on the screen is the gloss value at that angle. Recalibration is required when changing the test angle.

[0094] (3) Corrosion performance test: The corrosion resistance of the coating is evaluated by testing the change in infrared emissivity of the coating after experiencing different corrosion times.

[0095] Test standards: emissivity range 0.05-1, temperature range 20-500°C, spectral range 8-14μm, uncertainty 0.02-0.07;

[0096] Test conditions: ambient temperature 20°C, ambient humidity 40% RH, test temperature 30°C;

[0097] Test equipment: 20-500℃ electric focus temperature measurement thermal imager;

[0098] Test method: Place the prepared coating in an existing salt solution for immersion. After a certain period of time, take it out and wipe off the liquid on the surface, and then test the infrared emissivity.

[0099] Figure 5 This is a graph showing the infrared emissivity test data for the coatings of Examples 1-3 and Comparative Example 1. It can be seen from the graph that as the amount of AC-K filler added decreases, the measured infrared emissivity gradually increases. In Comparative Example 1, when only 1 g of filler is added, the infrared emissivity is as high as 0.597, which means it has lost its low emissivity performance and has no practical application value.

[0100] Figure 6 The following graph shows gloss test data for Example 1 and Comparative Example 2. The graph shows that the gloss of Comparative Example 2, which does not include a matting agent in the filler, increases to 14.9, while the gloss of Example 1, which does include a matting agent, is only 7.1. These results demonstrate that the addition of a matting agent can effectively reduce the gloss of the coating, offering advantages in practical applications.

[0101] Figure 7 The graph shows the infrared emissivity of Examples 4-6 and Comparative Examples 3-4 as a function of corrosion time. As can be seen from the graph, the corrosion resistance of the modified coating is greatly improved compared to the unmodified coating. The emissivity of the coating before modification (Comparative Example 3) increased from 0.10 to 0.70 after being immersed in salt water for 700 hours; and although the emissivity of the coating after modification with the coupling agent also increased, the emissivity changed relatively little in the early stages of corrosion during the corrosion process. As the corrosion time increased, the change in emissivity gradually decreased, and finally tended to a stable value (the emissivity of the coating increased from 0.10 to 0.58, 0.47, 0.35, 0.45 after 700 hours of corrosion). This stable value is lower than the emissivity value of the coating before modification after corrosion. Figure 7 It can also be seen that coatings modified with different coupling agent concentrations exhibit differences in corrosion resistance. The coating modified with an excessive coupling agent concentration (Comparative Example 4) has a significantly higher emissivity after 400 hours of corrosion than the coatings in the other examples, indicating that its corrosion resistance is weaker than the coatings modified with appropriate coupling agent concentrations (Examples 1, 4-6). Therefore, the present invention confirms that the amount of coupling agent in the modified filler powder must also be controlled within a reasonable range.

[0102] In summary, the present invention successfully prepared a low-gloss, corrosion-resistant, low-infrared emissivity filler and an infrared stealth coating through a liquid-phase reduction method and surface modification with a coupling agent. Surface modification of Al and Cu powders using a coupling agent can effectively improve the interfacial interaction between the polymer and the filler. After the Cu powder is modified with a coupling agent, the density of the composite coating system is further improved, and the porosity is significantly reduced compared to the unmodified coating, thereby reducing the permeation rate of corrosive ions and effectively slowing down the corrosion of the coating by corrosion factors. In addition, the present invention reduces the gloss of the coating while maintaining low infrared emissivity by adding a matting agent to the filler, which has practical application value.

[0103] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. A low-gloss, corrosion-resistant, low-infrared emissivity filler, characterized in that: The low infrared emissivity filler is prepared from the following raw material components in parts by mass: 20-40 parts of Cu powder, 5-15 parts of Al powder, 2-5 parts of matting agent, 1-2 parts of the first additive, 1-2 parts of the second additive, and 1-12 parts of coupling agent; The matting powder includes one or more of bronze powder, nano titanium dioxide, and fumed silica; The first additive includes one or more of stearic acid, palmitic acid, oleic acid, and citric acid; The second additive includes one or more of glycine, p-aminobenzoic acid, and β-alanine.

2. The low-gloss, corrosion-resistant, low-infrared emissivity filler according to claim 1, characterized in that: The coupling agent includes one or more of an aminosilane coupling agent, an epoxysilane coupling agent, a methacryloxysilane coupling agent, and a mercaptosilane coupling agent.

3. The low gloss, corrosion-resistant, low infrared emissivity filler according to claim 1, characterized in that: The particle size of the Cu powder is 10-25 μm, and the particle size of the Al powder is 10-25 μm; The average particle size of the low infrared emissivity filler is 10-25 μm; The low infrared emissivity filler has an aspect ratio of 50-500.

4. The low-gloss, corrosion-resistant, low-infrared emissivity filler according to claim 1, characterized in that: The Cu powder is prepared by the following method: S1: heating an aqueous solution containing copper salt, alkali and glucose under alkaline conditions, and separating the supernatant containing Cu2O after standing; S2: adding an anti-settling agent, NH4Cl and a reducing agent to the upper clear liquid, and performing a reduction reaction in a protective gas atmosphere to obtain the Cu powder.

5. The low gloss, corrosion-resistant, low infrared emissivity filler according to claim 4, characterized in that: In step S1, the mass ratio of the copper salt, the base and the glucose is (1.2-1.8):1:(2-3); The heating temperature is 75-85° C., and the heating time is 0.5-1.5 h.

6. The low gloss, corrosion-resistant, low infrared emissivity filler according to claim 4, characterized in that: In step S2, the anti-settling agent is polyvinyl pyrrolidone, and the mass ratio of the anti-settling agent to Cu2O is 1:(45-60); The molar ratio of NH4Cl and Cu2O is (0.2-0.5):1; The reducing agent is hydrazine hydrate, and the mass ratio of hydrazine hydrate to Cu2O is (2.2-2.8):1; The temperature of the reduction reaction is 75-85° C., and the time of the reduction reaction is 4-8 hours.

7. The low gloss, corrosion-resistant, low infrared emissivity filler according to claim 1, characterized in that: The low infrared emissivity filler is prepared by the following method: Cu powder, Al powder, matting powder, a first additive, and a second additive are weighed and mixed in proportion, and then ball-milled, filtered, and dried to obtain floating Al-Cu powder; The floating Al-Cu powder is dispersed in an organic solvent and a coupling agent is added to react, and the mixture is filtered and dried to obtain the low infrared emissivity filler.

8. The low gloss, corrosion-resistant, low infrared emissivity filler according to claim 7, characterized in that: The ball-to-material ratio of the ball mill is (5-15):1, the ball milling time is 4-8 hours, and the ball milling speed is 300-400 rpm.

9. An infrared stealth coating comprising the low infrared emissivity filler according to any one of claims 1 to 8, characterized in that: The infrared stealth coating is prepared from the following raw material components in parts by mass: 2-4 parts of a low infrared emissivity filler, 2-4 parts of a resin matrix, 2.5-3.5 parts of a curing agent, and 2-15 parts of an organic solvent.

10. The infrared stealth coating according to claim 9, characterized in that: The resin matrix includes one or more of polyurethane resin, epoxy-modified polyurethane resin, and modified acrylic resin; The curing agent includes one or more of an isocyanate curing agent, an aliphatic curing agent, and a polyol curing agent; The organic solvent includes one or more of butyl acetate, acetone, xylene, ethanol, and isopropanol.

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