Film forming method of infrared stealth film with low emissivity

Abstract

The invention discloses a film forming method of an infrared stealth film with low emissivity, which comprises the following steps: placing a base cloth in a prepared pigment sol of an optical camouflage coating, pulling the base cloth and forming a liquid film of the optical camouflage coating on the surface of the base cloth, and forming a gel film of the optical camouflage coating after the liquid film is dried; immersing the gel film into the sol prepared by the protective layer, then lifting the base cloth, and forming a protective layer film on the surface of the gel film; spraying the low-emissivity nano functional coating solution on the protective layer film to form a low-emissivity nano functional coating film; and spraying the solution prepared by the protective layer on the low-emissivity nano functional coating film to form the infrared stealth film. According to the film forming method, the consistency of the thickness of a liquid film and the thickness of a protective layer film can be guaranteed, the problem that blockage is likely to be formed at a nozzle and an air cap in the spraying process is effectively solved, the spraying uniformity and the spraying quality can be effectively improved, and an infrared stealth film material with the low reflectivity is finally formed.

Description

Technical Field

[0001] The invention relates to the technical field of infrared stealth film material forming, and in particular to a film forming method of an infrared stealth film with low emissivity. Background Art

[0002] The rapid development of infrared reconnaissance technology has brought new threats to military targets. The role of infrared stealth is to change or reduce the infrared characteristics or thermal radiation characteristics of the target, reduce the difference in infrared radiation characteristics between the detected target and the complex environment, make it difficult for the detection system to detect or reduce the detection effect of the detection system, thereby improving the survivability of military targets. In order to protect military weapons and equipment from the attack of infrared guided weapons and improve their survivability in the battlefield environment, they need to have a certain infrared stealth capability. Therefore, infrared stealth materials and infrared stealth technologies for the purpose of countering enemy infrared reconnaissance and attack have received high attention and have developed rapidly.

[0003] To prevent thermal infrared reconnaissance, we must try to make the infrared characteristics of the target as close to the infrared characteristics of the background as possible. Therefore, there are two most effective ways to achieve infrared camouflage: one is to control the surface temperature of the target so that the temperature of the detected target surface is as close as possible to the surrounding environment; the other is to use low-emissivity materials to adjust the emissivity of the object surface so that the infrared radiation contrast between the target and the background is as small as possible. Low-emissivity coatings are the most commonly used and basic material form. The main reason for the current high emissivity of infrared stealth materials and their poor compatibility with visible light camouflage is not only the choice of materials, but also the process control during the film formation process of the material, which has a great influence on the emissivity of the stealth material. Summary of the invention

[0004] In response to the above-mentioned problems, the present invention aims to provide a method for forming an infrared stealth film with low emissivity, which can achieve consistency in liquid film thickness, while solving the blockage problem that is easily formed at the nozzle and the wind hood, and can effectively improve the spraying uniformity and spraying quality, and ultimately form an infrared stealth film material with low reflectivity.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows: a film-forming method of an infrared stealth film with low emissivity, wherein the infrared stealth film is a layered structure, including a protective layer, a low-emissivity nano-functional coating, an optical camouflage coating and a base fabric; characterized in that the film-forming method comprises the following steps:

[0006] S1, placing the base fabric in the prepared pigment sol of the optical camouflage coating, then pulling the base fabric to form a liquid film of the optical camouflage coating on the surface of the base fabric, and forming a gel film of the optical camouflage coating after the liquid film is dried;

[0007] S2, immersing the gel film into the sol configured with the protective layer, and then pulling the base cloth to form a protective layer film on the surface of the gel film;

[0008] S3, spraying the low-emissivity nano-functional coating solution on the protective layer film to form a low-emissivity nano-functional coating film;

[0009] S4. Spraying the solution prepared for the protective layer onto the low-emissivity nano-functional coating film to form an infrared stealth film.

[0010] Preferably, in steps S1-S2, the descending speed of the base fabric is 2 mm / s, the pulling-up speed is 1 mm / s, the dipping time is 30 s, and the stopping time is 60 s.

[0011] Preferably, in steps S1-S2, the drying temperature of the liquid film and the protective layer film is 30°C, and the drying time is 8-12 hours.

[0012] Preferably, in steps S3-S4, the spraying interval is 150-200 mm; and the running speed is 300-400 mm / s.

[0013] Preferably, the spraying includes a spray gun, and a first anti-clogging structure for driving and clearing the blockage is provided at the nozzle of the spray gun.

[0014] Preferably, the first anti-clogging mechanism is a filter screen arranged inside the nozzle and at the port thereof, and the filter screen is arranged obliquely inside the nozzle.

[0015] Preferably, the spray gun has a hood mounted at its nozzle, the hood has a center hole corresponding to the nozzle straight line, and a second anti-clogging structure for driving and clearing blockages formed by spraying is provided at the inner port of the center hole.

[0016] Preferably, the second anti-clogging structure is a storage tank opened outside the inner port of the central hole.

[0017] The beneficial effect of the present invention is that during the pulling operation, the lifting plate and other components can effectively block and limit the rolling of the sol liquid surface generated by the base cloth when the base cloth is lifted, especially when the base cloth is lifted up, so as to maintain the stability of the liquid surface, thereby avoiding the problem of sol adhering again to the surface of the base cloth pulled out of the liquid surface due to liquid level fluctuations, thereby ensuring the consistency of the liquid film thickness, and ultimately ensuring the consistency of the multi-layer structure of the formed thin film material and the low emissivity index.

[0018] Furthermore, through the filter screen and storage tank structure, the spray liquid can be sprayed continuously, solving the blockage problem that is easy to form at the nozzle and the wind cap, which can effectively improve the spraying uniformity and spraying quality, and finally form an infrared stealth film material with low reflectivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the base cloth lifting structure of the present invention.

[0020] Figure 2 It is a diagram of the base cloth lifting operation of the present invention.

[0021] Figure 3 It is a side view of base cloth lifting of the present invention.

[0022] Figure 4 This is a diagram showing the fluctuation of the sol when the base fabric of the present invention is lifted and adheres to the base fabric pulled out of the liquid surface.

[0023] Figure 5 The present invention is to provide a liquid level retaining plate in a container.

[0024] Figure 6 It is a schematic diagram of the spray gun structure of the present invention.

[0025] Figure 7 For the present invention Figure 6 Enlarged view of the structure at point A in the middle.

[0026] Figure 8 It is a diagram showing the sol liquid in the nozzle of the present invention ready to be ejected.

[0027] Fig. 9 It is a diagram showing the spraying of sol liquid from the middle hole of the hood of the present invention.

[0028] Fig.10 It is a diagram showing a blockage of a plug at the nozzle of the present invention.

[0029] Fig.11 This is a diagram showing that the present invention uses a filter screen to intercept and block the obstruction in the nozzle.

[0030] Fig.12 This is a diagram of a filter screen tilted in the present invention.

[0031] Fig.13 The figure shows that the middle hole of the hood of the present invention is blocked by a blocking object.

[0032] Fig.14 This is a diagram of a storage tank with a plugging object arranged outside the middle hole of the present invention.

[0033] Fig.15 For the present invention Fig.14 Illustration of the basic blockage entering the storage tank.

[0034] Fig.16 It is a diagram of a storage tank with different heights on both sides of the present invention.

[0035] Fig.17 For the present invention Fig.16 Illustration of the basic blockage entering the storage tank.

[0036] In the figure: 1-lifting plate; 2-base cloth; 3-container; 4-liquid level maintaining plate; 5-spray gun; 5a-nozzle; 51-wind cap; 51a-middle hole; 6-filter screen; 51b-storage tank. DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0038] Refer to the attached Figures 1 to 17 The film forming method of a low-emissivity infrared stealth film is shown, wherein the infrared stealth film is a layered structure, including a protective layer, a low-emissivity nano-functional coating, and an optical camouflage coating. The protective layer material preferably includes one of polyurethane, acrylic resin, and silicone-acrylate resin and a solvent; the solvent of the protective layer material includes one of butyl acetate and xylene; the thickness of the protective layer material is preferably 1μm to 2μm; and the solid content of the protective layer material is 5% to 20%.

[0039] The low-emissivity nano-functional coating comprises metal nanowires and a PMMA film; the thickness of the low-emissivity nano-functional coating is 2 μm-6 μm; the diameter of the metal nanowires is 20 nm-90 nm; and the length of the metal nanowires is 5 μm-60 μm.

[0040] The selection of the optical camouflage coating pigment is obtained by calculating the color difference tristimulus values.

[0041] The above structural layer is made into an infrared stealth film with low emissivity, and the performance of low emissivity can be ensured. The present application provides a film forming method, which specifically includes the following steps:

[0042] S1. Place the (film-forming) substrate in the prepared pigment sol of the optical camouflage coating, and then pull the substrate. The pulling adopts the immersion pulling coating process, using the Shanghai Sanyan SYDC-100H model Dip Coater, which is to immerse the substrate in the pre-prepared pigment sol of the optical camouflage coating at a certain speed, and then slowly and evenly pull the substrate out of the sol. Under the action of viscosity and gravity, a uniform liquid film is formed on the surface of the substrate, and then the solvent evaporates. After the liquid film is dried (drying temperature is 30°C, drying time is 8h), a layer of gel film is attached to the surface of the substrate.

[0043] The descending speed of the base fabric is preferably 2 mm / s, the lifting speed is 1 mm / s, the immersion time is 30 s, and the stop time is 60 s. The number of coating times is preferably 10 times.

[0044] S2, immersing the gel film into the sol configured with the protective layer, and then pulling the base fabric (using the same pulling equipment and parameters as above, the pulling times are preferably 5 times, and the drying time is 10 hours) to form a protective layer film on the surface of the gel film.

[0045] During the lifting operation of step S1-S2, the main structures are as follows Figure 1 As shown, the base fabric 2 is clamped at the bottom of the lifting plate 1, and the bottom side of the base fabric 2 has a container 3 containing the sol. During operation, the lifting plate 1 lifts the base fabric 2 up and down. Figure 2 As shown, the base fabric 2 is immersed in the sol liquid, and a liquid film is attached to the base fabric 2. In the process of pulling the base fabric 2 up and down, there is a certain pulling speed, which drives the sol liquid to have Figure 3 The tumbling action indicated by the middle arc arrow causes the liquid level of the sol liquid to fluctuate when the base cloth 2 is lifted. Figure 3 As shown in the figure on the right, the sol liquid will adhere to the surface of the base fabric 2 that has been lifted and detached again under the wave state, causing the thickness of the sol liquid on the surface of the base fabric 2 to increase, such as Figure 4 As shown in a, the consistency of the thickness of the single-attached sol cannot be guaranteed. At the same time, although the thickness of the re-attached sol liquid will decrease when it flows down along the surface of the base fabric 2, the thickness of the liquid film in the downstream area will increase to a greater extent. The thickness of the liquid film and the protective layer film is in the micron level, and thus the thickness consistency of the formed film material cannot be well guaranteed, affecting the emissivity of the final formed film.

[0046] Therefore, in order to solve the above-mentioned problems of pulling, Figure 5 As shown, a liquid level maintaining plate 4 is arranged on the liquid surface of the container 3 and close to the liquid surface, and a strip hole (not shown in the figure) through which the base cloth 2 is penetrated is opened in the liquid level maintaining plate 4. When the base cloth 2 is lifted, especially when the base cloth 2 is lifted up, the rolling of the sol liquid surface generated by the base cloth 2 can be effectively blocked and restricted to maintain the stability of the liquid surface, thereby avoiding the problem of sol adhering again to the surface of the base cloth 2 pulled out of the liquid surface due to liquid level fluctuations, thereby ensuring the consistency of the liquid film thickness, and finally ensuring the consistency of the multi-layer structure of the formed thin film material and the low emissivity index.

[0047] S3, spraying the low-emissivity nano-functional coating solution on the protective layer film to form a low-emissivity nano-functional coating film. Spraying is preferably spraying with a spray gun 5, which has the advantages of high production efficiency and convenient construction, and is suitable for industrial production. Therefore, this application is implemented by spraying with a spray gun 5 to provide a guiding basis for subsequent industrial production.

[0048] According to the experimental implementation of the present application, the spraying interval of the spray gun 5 is preferably 150-200 mm, and the running (moving) speed is 300-400 mm / s. The spraying interval is inversely proportional to the running speed.

[0049] At present, when spraying, the coating liquid is sprayed out in a mist state, and the coating liquid is usually mixed and stirred by multiple materials. Due to the influence of uneven stirring and impurities, it is inevitable that the spray liquid will gather into a solid state during the spraying process to block or partially block the nozzle 5a of the spray gun 5. Blockage occurs during the continuous spraying process. After cleaning the spray gun 5, the second spraying will form an overlapping edge, which will greatly affect the emissivity of the infrared stealth film; and after partial blockage, the aperture of the spray is reduced, that is, the spray range is affected, making the spraying uneven, which also affects the emissivity of the film. Therefore, the blockage of the spray gun 5 during spraying is one of the main factors affecting the molding of the film material.

[0050] Therefore, in order to avoid the influence of clogging of the spray gun 5 during the spraying process, the present application provides a first anti-clogging structure at the nozzle 5a of the spray gun 5 to drive and clean the clogging. The specific structure is as follows: Fig.11 As shown, the first anti-clogging mechanism is a filter screen 6 disposed inside the nozzle 5a and at the end thereof. When the sprayed coating liquid reaches the nozzle 5a, it is first filtered by the filter screen 6. Fig.11 As shown in the state, impurities that are blocking the nozzle 5a are filtered out to avoid clogging when reaching the nozzle 5a, thereby ensuring the continuous spraying process and having a consistent spraying range, ensuring continuous spraying effects, and improving the film forming quality.

[0051] In order to avoid the problem that more blockages accumulate on the filter screen 6 and affect the flow of the spray liquid, Fig.12 As shown, the filter screen 6 is tilted in the nozzle 5a. That is, under the action of continuous liquid spraying, the blockage on the filter screen 6 is driven to move toward one side. Fig.12 The state shown can avoid the blocking effect of blockage on the flow of spray liquid.

[0052] The conventional spray gun 5 has a hood 51 mounted at its nozzle 5a, such as Figure 7 As shown, the hood 51 has a central hole 51a corresponding to the nozzle 5a in a straight line. The shape of the spray can be adjusted through the hood 51. It is usually a fan-shaped structure. The width and size of the fan-shaped structure can be adjusted to adapt to different spray requirements. When the spray liquid is sprayed from the nozzle 5a and before entering the central hole 51a of the hood 51, if the raw material of the spray liquid or the mixed raw material has a certain viscosity, then under a larger spray pressure (because the hood 51 can change the shape and size of the spray, it has a different caliber size compared to the nozzle, so that the spray liquid sprayed from the nozzle is pressurized again), it is also easy to gather again in the gap between the nozzle and the hollow to form a blockage, Fig.13As shown, in order to avoid the problem of secondary blockage blocking the middle hole 51a of the wind cap 51, the present application provides a second anti-blockage structure at the inner port of the middle hole 51a to drive and clean the blockage formed by injection, so as to solve the problem of blockage at the middle hole 51a.

[0053] Specific structure such as Figure 14-15 As shown, the second anti-blocking structure is a storage tank 51b opened outside the inner port of the middle hole 51a. Preferably, the inner depth of the storage tank 51b is lower than the port of the middle hole 51a. When a blockage occurs, the pressure of the injection will drive the blockage into the lower storage tank 51b, thereby ensuring the penetration of the middle hole 51a, so that the spray can be sprayed continuously to solve the blockage formed twice. The width of the storage tank 51b is greater than the diameter of the conventionally formed blockage, so as to avoid the blocking effect of the blockage on the middle hole 51a caused by the blockage entering the storage tank 51b.

[0054] Furthermore, in order to avoid the problem that the blockage is squeezed at the end of the middle hole 51a by the spraying pressure and is difficult to smoothly enter the storage tank 51b, Figure 16-17 As shown, the depths of the left and right sides of the storage tank 51b are inconsistent, which means that the port of the middle hole 51a forms an oblique structure. When the blockage reaches the port of the middle hole 51a, it is driven by the injection and enters the storage tank 51b on the side with a larger depth along the oblique structure, thereby avoiding blockage caused by being squeezed at the port of the middle hole 51a by the spraying pressure.

[0055] The spray gun 5 can spray a uniform coating structure without overlapping edges, which can effectively improve the spraying quality of the coating.

[0056] S4, spraying the solution of the protective layer configuration on the low emissivity nano-functional coating film to form an infrared stealth film. This step also uses the spray gun 5 of the above step S3 to ensure the molding quality and low reflectivity of the final infrared stealth film.

[0057] The film material forming process disclosed in the present invention is as follows:

[0058] S1. The prepared pigment sol of the optical camouflage coating is placed in a container 3, and a liquid level holding plate 4 is positioned at the liquid level to be flat against the liquid surface. Then, the base fabric is repeatedly lifted by the lifting plate 1. A uniform liquid film is formed on the surface of the substrate under the action of viscosity and gravity. Subsequently, the solvent evaporates, and a gel film is attached to the surface of the base fabric after the liquid film is dried (drying temperature is 30°C, drying time is 8h).

[0059] S2, immersing the gel film into the sol configured with the protective layer in the same manner as step S1, and then pulling up the base fabric to form a protective layer film on the surface of the gel film.

[0060] S3, spraying the low emissivity nano functional coating solution onto the protective layer film through the spray gun 5 to form a low emissivity nano functional coating film. During the spraying process, the filter screen 6 and the storage tank 51b are used to timely clean the blockage to avoid the blockage problem during the spraying process.

[0061] S4, spraying the solution prepared for the protective layer onto the low-emissivity nano-functional coating film through a spray gun 5 to form an infrared stealth film.

[0062] The above shows and describes the basic principle, main features and advantages of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention claimed.

Claims

1. A method for forming a film with low emissivity infrared stealth film, wherein the infrared stealth film is a layered structure, including a protective layer, a low emissivity nano-functional coating, an optical camouflage coating and a base fabric; characterized in that: The film forming method comprises the following steps: S1, placing the base fabric in the prepared pigment sol of the optical camouflage coating, then pulling the base fabric to form a liquid film of the optical camouflage coating on the surface of the base fabric, and forming a gel film of the optical camouflage coating after the liquid film is dried; S2, immersing the gel film into the sol configured with the protective layer, and then pulling the base cloth to form a protective layer film on the surface of the gel film; S3, spraying the low-emissivity nano-functional coating solution on the protective layer film to form a low-emissivity nano-functional coating film; S4. Spraying the solution prepared for the protective layer onto the low-emissivity nano-functional coating film to form an infrared stealth film.

2. The film forming method according to claim 1, characterized in that: In step S1-S2, the descending speed of the base fabric is 2 mm / s, the lifting speed is 1 mm / s, the dipping time is 30 s, and the stopping time is 60 s.

3. The film forming method according to claim 2, characterized in that: In step S1-S2, the drying temperature of the liquid film and the protective layer film is 30°C, and the drying time is 8-12 hours.

4. The film forming method according to claim 3, characterized in that: In steps S3-S4, the spraying interval is 150-200 mm; the running speed is 300-400 mm / s.

5. The film forming method according to claim 4, characterized in that: The spraying comprises a spray gun, and a first anti-clogging structure for driving and clearing the blockage is arranged at the nozzle of the spray gun.

6. The film forming method according to claim 5, characterized in that: The first anti-clogging mechanism is a filter screen arranged inside the nozzle and at the port thereof, and the filter screen is arranged obliquely in the nozzle.

7. The film forming method according to claim 6, characterized in that: The spray gun has a hood mounted at its nozzle, the hood has a central hole corresponding to the nozzle straight line, and a second anti-clogging structure for driving and clearing the blockage formed by the spraying is arranged at the inner port of the central hole.

8. The film forming method according to claim 7, characterized in that: The second anti-blocking structure is a storage tank opened outside the inner port of the central hole.

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