Coated fabric with radiation cooling and infrared stealth functions and preparation method thereof

Abstract

The invention discloses a coated fabric with radiation cooling and infrared stealth functions and a preparation method of the coated fabric. The coated fabric with the radiation cooling and infrared stealth functions comprises a fabric substrate, and a radiation cooling coating and an infrared stealth coating which are respectively coated on two side surfaces of the fabric substrate, the radiation cooling coating is a water-based environment-friendly coating coated with inorganic nanoparticles; and the infrared stealth coating is a binder polymer coating coated with reflective particles. According to the coated fabric with the radiation cooling and infrared stealth functions, the two contradictory functions of infrared stealth and radiation cooling are combined together in a double-sided coating mode.

Description

Technical Field

[0001] The present invention relates to the technical field of functional fabric preparation, and in particular to a coated fabric with both radiation cooling and infrared stealth functions and a preparation method thereof. Background Art

[0002] With the continuous advancement of optoelectronic technology, infrared detection and reconnaissance technology has been widely used in modern warfare, posing a serious challenge to weaponry and personnel safety. According to the Stefan-Boltzmann law, all objects with a temperature above absolute zero continuously emit infrared thermal radiation. Therefore, reducing an object's surface temperature and emissivity is an effective way to reduce its probability of detection.

[0003] Infrared stealth coatings utilize their low emissivity to minimize the difference in thermal radiation between a target object and its background, thereby achieving infrared stealth. Meanwhile, global warming exacerbates the urban heat island effect, further increasing surface temperatures. Daytime passive radiative cooling technology reduces surface temperatures by increasing solar reflectivity and radiating heat through atmospheric windows, without consuming additional energy.

[0004] Chinese patent publication CN118703102A utilizes a water-based polyurethane emulsion, graphene powder, MXene dispersion, silica aerogel powder, and hollow glass microspheres to prepare an infrared stealth coating that effectively reduces a target's infrared thermal radiation while also exhibiting flame retardancy. Chinese patent publication CN118185444A utilizes a two-component formulation of acrylic resin and HDI as an adhesive, metallic aluminum powder as a functional filler, and a catalyst to shorten the curing time, resulting in an infrared stealth coating with a short room-temperature curing time and excellent mechanical properties. Chinese patent publication CN118621455A utilizes zinc sulfide nanoparticles grown in situ on cellulose fibers. This radiative cooling fiber exhibits excellent mechanical properties, water absorption, and moisture permeability, while also exhibiting high reflectivity in the sunlight band and high infrared emissivity in the atmospheric window band. It effectively achieves daytime radiative cooling.

[0005] However, most current radiative cooling fabric coatings lack durability and use organic solvents, which pollute the environment during curing. For equipment with complex and irregular surfaces, such as fighter jets and missiles, the development of flexible metal coatings (such as coated fabrics) is needed because these materials offer greater adaptability and flexibility. Summary of the Invention

[0006] The present invention provides a coated fabric with both radiation cooling and infrared stealth functions, combining the two contradictory functions of infrared stealth and radiation cooling together through double-sided coating.

[0007] The technical solutions of the present invention are as follows: A coated fabric with both radiation cooling and infrared stealth functions, comprising a fabric base, and a radiation cooling coating and an infrared stealth coating respectively coated on both sides of the fabric base; The radiation cooling coating is a water-based environmentally friendly coating coated with inorganic nanoparticles; the infrared stealth coating is a binder polymer coating coated with reflective particles.

[0008] The infrared stealth coating of the present invention uses a polymer as a binder, reflective particles as infrared reflective particles, and metal powder with low mid-infrared emissivity, resulting in an infrared stealth coating with low mid-infrared emissivity, good wear resistance, and excellent flexibility. The radiative cooling coating uses a water-based environmentally friendly emulsion as a binder and inorganic nanoparticles as functional particles. It emits no VOCs during curing, exhibits high fastness, and has high solar reflectivity and atmospheric window emissivity.

[0009] The coated fabric of this invention combines radiative cooling with infrared stealth, solving both the infrared stealth and radiative cooling problems without requiring energy input. On the radiative cooling side, it has high atmospheric window emissivity and solar reflectivity, providing excellent cooling performance. On the infrared stealth side, it has low infrared emissivity and strong stability, and the transition between radiative cooling and infrared stealth is achieved simply by flipping.

[0010] Preferably, based on the area of the fabric, the coating amount of the infrared stealth coating is 3-25 mg·cm -2 The coating amount of the radiation cooling coating is 2~25 mg·cm -2 .

[0011] As the amount of infrared stealth coating applied increases, the metal powder on the surface becomes denser and the gaps between the metal powders become smaller, forming a dense mid-infrared reflective layer. This increases the surface's mid-infrared reflectivity, thereby reducing its mid-infrared emissivity. The reflectivity and emissivity of radiative cooling coatings also increase with increasing application, improving their ability to scatter sunlight and radiate heat. However, further application of infrared stealth coatings and radiative cooling coatings results in a slight decrease in reflectivity and emissivity, rather than a change in reflectivity.

[0012] Further preferably, based on the area of the fabric, the coating amount of the infrared stealth coating is 10-20 mg·cm -2 The optimal coating amount of the radiation cooling coating is 15~25 mg·cm -2 .

[0013] Preferably, the radiation cooling coating is solidified from an environmentally friendly aqueous emulsion containing inorganic nanoparticles; the environmentally friendly aqueous emulsion contains an emulsifier, a polymer, an organosilicon material, and a catalyst.

[0014] The emulsifier is formed by condensation polymerization of a hydrophilic polymer and a lipophilic polymer, wherein the hydrophilic polymer is at least one of polyethylene glycol, polyvinyl alcohol, ethylene oxide propylene oxide copolymer, and polyhydroxyethyl methacrylate; the lipophilic polymer is an epoxy resin, including one of bisphenol A epoxy resin, alicyclic epoxy resin, and phenolic epoxy resin.

[0015] Furthermore, the emulsifier is prepared by polycondensation of polyethylene glycol and bisphenol A epoxy resin.

[0016] The ratio of polyethylene glycol to bisphenol A epoxy resin determines the HLB value of the macromolecular emulsifier. When synthesizing the emulsifier, the higher the proportion of polyethylene glycol, the more hydrophilic segments there are, and the more hydrophilic the emulsifier is. Preferably, the optimal ratio of polyethylene glycol to bisphenol A epoxy resin is 3-5:1.

[0017] The polymer is at least one of bisphenol A epoxy resin, alicyclic epoxy resin and phenolic epoxy resin.

[0018] The catalyst is one of triphenylphosphine, dibutyltin dilaurate, potassium persulfate and boron trifluoride etherate.

[0019] The organic silicon material is at least one of polyether modified silicone oil, amino silicone oil, phosphate modified silicone oil, carboxyl modified silicone oil and betaine type organic silicon.

[0020] Preferably, the surface of the radiation cooling coating also has a hydrophobic layer.

[0021] The hydrophobic layer is an organic silicon polymer layer coated with hydrophobic inorganic particles.

[0022] The organosilicon polymer is at least one of polydimethylsiloxane, polymethylphenylsiloxane and polyhydrogenmethylsiloxane.

[0023] The organosilicon polymer in the hydrophobic layer contains a large number of methyl groups, resulting in a low surface energy. Furthermore, the Si-O-Si bonds in the organosilicon have a high bond energy, making them less susceptible to breakage by ultraviolet radiation, resulting in excellent weather resistance. Hydrophobic inorganic particles create a rough surface in the hydrophobic layer, creating a hydrophobic effect. This surface hydrophobic layer imparts excellent self-cleaning properties to the fabric.

[0024] Preferably, the binder polymer in the infrared stealth coating is at least one of polyurethane, styrene-butadiene-styrene block copolymer, silicone resin, propylene glycol rubber, epoxy resin, and polyethylene.

[0025] Preferably, the reflective particles in the infrared stealth coating are at least one of aluminum powder, silver powder, copper powder, indium tin oxide, and nickel powder.

[0026] The material of the fabric base is at least one of cotton, polyester, nylon, linen and non-woven fabric.

[0027] Most preferably, the fabric base is polyester. Polyester offers high strength and excellent abrasion resistance. It has excellent elasticity, quickly recovering after stretching, and exhibits excellent wrinkle resistance. Furthermore, polyester is chemically stable and highly resistant to most chemicals. Even under certain acidic conditions, polyester maintains good acid resistance and is not easily corroded.

[0028] The present invention also provides a method for preparing the coated fabric having both radiation cooling and infrared stealth functions, comprising the following steps: (1) The hydrophilic polymer and the lipophilic polymer are mixed and stirred uniformly in an inert protective atmosphere, a catalyst is added, and the mixture is reacted at 150-200°C for 1-5 hours to obtain an emulsifier; (2) emulsifying an emulsifier, an organosilicon material, a hydrophilic polymer and deionized water to obtain an organosilicon-modified epoxy resin emulsion; (3) mixing and stirring the silicone-modified epoxy resin emulsion, curing agent, and inorganic nanoparticles, applying the mixture to a fabric substrate, and drying and curing the mixture to obtain a radiant cooling coating; (4) dissolving the organosilicon polymer in an organic solvent, adding hydrophobic inorganic particles to obtain a suspension, and spraying the suspension onto the surface of the radiation cooling coating to obtain a hydrophobic layer; (5) Add reflective particles to the adhesive polymer, stir evenly, and apply them to the other side of the fabric substrate to obtain an infrared stealth coating.

[0029] The fabric substrate is treated with anhydrous ethanol and ultrasonically before finishing to remove impurities on the surface of the fabric substrate.

[0030] In step (2), the emulsification includes: first obtaining a crude emulsion by a mechanical stirring method, then homogenizing it with a homogenizer, and obtaining a stable silicone-modified epoxy resin emulsion after filtering.

[0031] In step (3) and step (5), the method for applying the mixed liquid to the fabric surface can be any one of scraping, spraying, and spin coating.

[0032] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention combines the two contradictory functions of infrared stealth and radiation cooling by means of double-sided coating.

[0033] (2) The radiant cooling coating uses a water-based environmentally friendly emulsion, and the curing process is environmentally friendly and has no VOC emissions. The introduction of silicone and hydrophobic layers improves the coating's UV resistance and hydrophobic properties, making it easier to use outdoors for a long time.

[0034] (3) The infrared stealth coating prepared by the present invention has good mechanical stability, low emissivity and high fastness.

[0035] (5) The raw materials used in the present invention are cheap and easily available, the preparation method is simple, and it is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a photograph of the surface water contact angle of the radiation cooling side coating of the infrared stealth radiation cooling dual-function Janus coated fabric prepared in Example 3.

[0037] Figure 2 This is a real-time temperature change curve of the infrared stealth radiation cooling dual-function Janus coated fabric prepared in Example 3 and the environment.

[0038] Figure 3 This is an infrared thermal imaging image of the infrared stealth side of the infrared stealth radiation cooling dual-function Janus coated fabric prepared in Example 3. DETAILED DESCRIPTION

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be noted that the following examples are intended to facilitate understanding of the present invention and do not have any limiting effect on the present invention.

[0040] The following examples disclose a method for preparing a Janus coated fabric having the dual functions of infrared stealth, radiation and cooling.

[0041] Example 1 (1) Place 400 parts by mass of polyethylene glycol-6000 and 105 parts of epoxy resin E-51 in a three-necked flask, add a small amount of cosolvent, introduce nitrogen, and stir evenly at 65°C. After the polyethylene glycol and epoxy resin are completely dissolved, add 5 parts of potassium persulfate catalyst and a small amount of cosolvent and slowly add them dropwise to the mixture. Raise the temperature to 180°C and react for 4 hours to obtain a light yellow transparent macromolecular emulsifier.

[0042] (2) Take 15 parts of the above emulsifier, 40 parts of epoxy resin E-51, and 8 parts of hydrophilic silicone resin (polyether silicone resin) and stir them thoroughly in a three-necked flask at 60 degrees. First, slowly add deionized water, then increase the dropwise addition rate to a total of 150 parts of deionized water. Stir and disperse the emulsion at high speed for 40 minutes, then homogenize it in a homogenizer for 30 minutes, and filter it through a gauze to obtain a stable silicone-modified epoxy resin emulsion.

[0043] (3) Take 65 parts of the above emulsion and 5 parts of curing agent and stir and mix them evenly. Then add 80 parts of silicon dioxide (particle size 1 μm) and stir and mix them evenly to obtain a radiant cooling coating. Apply it on the polyester fabric substrate and cure it at high temperature for 1 hour.

[0044] (4) Take 10 parts of PDMS, 1 part of PDMS curing agent (Dow Corning), and 100 parts of tetrahydrofuran, stir thoroughly and dissolve evenly. Then add 20 parts of hydrophobic silica and disperse evenly to obtain a mixed solution. Spray this mixed solution onto the surface of the radiation cooling layer and cure at high temperature for 1 hour. The hydrophobic radiation cooling coating is obtained. The total coating amount of the radiation cooling coating and the hydrophobic coating is 18.4 mg cm -2 .

[0045] (5) Take 100 parts of polyurethane emulsion and 90 parts of aluminum powder, disperse them evenly to obtain infrared stealth coating, apply it to the other side of the polyester fabric, and cure it at high temperature. The coating amount is 14.5 mg·cm -2 The Janus coated fabric with dual functions of infrared stealth, radiation and cooling was obtained.

[0046] Example 2 (1) Place 400 parts by mass of polyethylene glycol-6000 and 105 parts of epoxy resin E-51 in a three-necked flask, add a small amount of cosolvent, introduce nitrogen, and stir evenly at 65°C. After the polyethylene glycol and epoxy resin are completely dissolved, add 5 parts of potassium persulfate catalyst and a small amount of cosolvent and slowly add them dropwise to the mixture. Raise the temperature to 180°C and react for 4 hours to obtain a light yellow transparent macromolecular emulsifier.

[0047] (2) Take 15 parts of the above emulsifier, 40 parts of epoxy resin E-51, and 8 parts of hydrophilic silicone resin and stir them thoroughly in a three-necked flask at 60 degrees. First, slowly add deionized water, then increase the dropwise addition rate to a total of 150 parts of deionized water. Stir and disperse the emulsion at high speed for 40 minutes, then homogenize it in a homogenizer for 30 minutes, and filter it through a gauze to obtain a stable silicone-modified epoxy resin emulsion.

[0048] (3) Take 65 parts of the above emulsion and 5 parts of curing agent and stir and mix them evenly. Then add 85 parts of calcium carbonate and stir and mix them evenly to obtain a radiant cooling coating. Apply it on the polyester fabric substrate and cure it at high temperature for 1 hour.

[0049] (4) Take 10 parts of PDMS, 1 part of PDMS curing agent, and 100 parts of tetrahydrofuran, stir thoroughly and dissolve evenly. Then add 20 parts of hydrophobic silica and disperse evenly to obtain a mixed solution. Spray this mixed solution onto the surface of the radiation cooling layer and cure it at high temperature for 1 hour. The hydrophobic radiation cooling coating is obtained, and the final coating amount is 20.5 mg cm -2 .

[0050] (5) Take 100 parts of polyurethane emulsion and 90 parts of aluminum powder, disperse them evenly to obtain infrared stealth coating, apply it to the other side of the polyester fabric, and cure it at high temperature. The coating amount is 14.5 mg·cm -2 The Janus coated fabric with dual functions of infrared stealth, radiation and cooling was obtained.

[0051] Example 3 (1) Place 400 parts by mass of polyethylene glycol-6000 and 105 parts of epoxy resin E-51 in a three-necked flask, add a small amount of cosolvent, introduce nitrogen, and stir evenly at 65°C. After the polyethylene glycol and epoxy resin are completely dissolved, add 5 parts of potassium persulfate catalyst and a small amount of cosolvent and slowly add them dropwise to the mixture. Raise the temperature to 180°C and react for 4 hours to obtain a light yellow transparent macromolecular emulsifier.

[0052] (2) Take 15 parts of the above emulsifier, 40 parts of epoxy resin E-51, and 8 parts of hydrophilic silicone resin and stir them thoroughly in a three-necked flask at 60 degrees. First, slowly add deionized water, then increase the dropwise addition rate to a total of 150 parts of deionized water. Stir and disperse the emulsion at high speed for 40 minutes, then homogenize it in a homogenizer for 30 minutes, and filter it through a gauze to obtain a stable silicone-modified epoxy resin emulsion.

[0053] (3) Take 65 parts of the above emulsion and 5 parts of curing agent and stir and mix them evenly. Then add 75 parts of zinc oxide and stir and mix them evenly to obtain a radiant cooling coating. Apply it on the polyester fabric substrate and cure it at high temperature for 1 hour.

[0054] (4) Take 10 parts of PDMS, 1 part of PDMS curing agent, and 100 parts of tetrahydrofuran, stir thoroughly and dissolve evenly. Then add 20 parts of hydrophobic silica and disperse evenly to obtain a mixed solution. Spray this mixed solution onto the surface of the radiation cooling layer and cure it at high temperature for 1 hour. The hydrophobic radiation cooling coating is obtained, and the final coating amount is 18.7 mg cm -2 .

[0055] (5) Take 100 parts of polyurethane emulsion and 90 parts of aluminum powder, disperse them evenly to obtain infrared stealth coating, apply it to the other side of the polyester fabric, and cure it at high temperature. The coating amount is 14.5 mg·cm -2 The Janus coated fabric with dual functions of infrared stealth, radiation and cooling was obtained.

[0056] Example 3 (1) According to the mass fraction, 400 parts of polyethylene glycol-6000 and 105 parts of epoxy resin E-51 were placed in a three-necked flask, a small amount of cosolvent was added, nitrogen was introduced, and the mixture was stirred at 65°C until the polyethylene glycol and epoxy resin were completely dissolved. 5 parts of potassium persulfate catalyst and a small amount of cosolvent were added and slowly added dropwise to the mixture. The temperature was raised to 180°C and the reaction was carried out for 4 hours to obtain a light yellow transparent macromolecular emulsifier.

[0057] (2) Take 15 parts of the above emulsifier, 40 parts of epoxy resin E-51, and 8 parts of hydrophilic silicone resin and stir them thoroughly in a three-necked flask at 60 degrees. First, slowly add deionized water, then increase the dropwise addition rate to a total of 150 parts of deionized water. Stir and disperse the emulsion at high speed for 40 minutes, then homogenize it in a homogenizer for 30 minutes, and filter it through a gauze to obtain a stable silicone-modified epoxy resin emulsion.

[0058] (3) Take 65 parts of the above emulsion and 5 parts of curing agent and stir and mix them evenly. Then add 75 parts of zinc oxide and stir and mix them evenly to obtain a radiant cooling coating. Apply it on the polyester fabric substrate and cure it at high temperature for 1 hour.

[0059] (4) Take 10 parts of PDMS, 1 part of PDMS curing agent, and 100 parts of tetrahydrofuran, stir thoroughly and dissolve evenly. Then add 20 parts of hydrophobic silica and disperse evenly to obtain a mixed solution. Spray this mixed solution onto the surface of the radiation cooling layer and cure it at high temperature for 1 hour. The hydrophobic radiation cooling coating is obtained, and the final coating amount is 18.7 mg cm -2 .

[0060] (5) Take 30 parts of SBS polymer and 150 parts of xylene and dissolve them completely at room temperature. Then add 85 parts of aluminum powder and disperse them evenly to obtain infrared stealth coating. Apply it to the other side of the polyester fabric and cure it at high temperature. The coating amount is 16.4 mg·cm -2 The Janus coated fabric with dual functions of infrared stealth, radiation and cooling was obtained.

[0061] Example 4 (1) Place 400 parts by mass of polyethylene glycol-6000 and 105 parts of epoxy resin E-51 in a three-necked flask, add a small amount of cosolvent, introduce nitrogen, and stir evenly at 65°C. After the polyethylene glycol and epoxy resin are completely dissolved, add 5 parts of potassium persulfate catalyst and a small amount of cosolvent and slowly add them dropwise to the mixture. Raise the temperature to 180°C and react for 4 hours to obtain a light yellow transparent macromolecular emulsifier.

[0062] (2) Take 15 parts of the above emulsifier, 40 parts of epoxy resin E-51, and 8 parts of hydrophilic silicone resin and stir them thoroughly in a three-necked flask at 60 degrees. First, slowly add deionized water, then increase the dropwise addition rate to a total of 150 parts of deionized water. Stir and disperse the emulsion at high speed for 40 minutes, then homogenize it in a homogenizer for 30 minutes, and filter it through a gauze to obtain a stable silicone-modified epoxy resin emulsion.

[0063] (3) Take 65 parts of the above emulsion and 5 parts of curing agent and stir and mix them evenly. Then add 75 parts of zinc oxide and stir and mix them evenly to obtain a radiant cooling coating. Apply it on the polyester fabric substrate and cure it at high temperature for 1 hour.

[0064] (4) Take 10 parts of PDMS, 1 part of PDMS curing agent, and 100 parts of tetrahydrofuran, stir thoroughly and dissolve evenly. Then add 20 parts of hydrophobic silica and disperse evenly to obtain a mixed solution. Spray this mixed solution onto the surface of the radiation cooling layer and cure it at high temperature for 1 hour. The hydrophobic radiation cooling coating is obtained, and the final coating amount is 18.7 mg cm -2 .

[0065] (5) Take 30 parts of SBS polymer and 150 parts of xylene and dissolve them completely at room temperature. Then add 80 parts of copper powder and disperse them evenly to obtain infrared stealth coating. Apply it to the other side of the polyester fabric and cure it at high temperature. The coating amount is 18.9 mg·cm -2 The Janus coated fabric with dual functions of infrared stealth, radiation and cooling was obtained.

[0066] Example 5 (1) Place 400 parts by mass of polyethylene glycol-6000 and 105 parts of epoxy resin E-51 in a three-necked flask, add a small amount of cosolvent, introduce nitrogen, and stir evenly at 65°C. After the polyethylene glycol and epoxy resin are completely dissolved, add 5 parts of potassium persulfate catalyst and a small amount of cosolvent and slowly add them dropwise to the mixture. Raise the temperature to 180°C and react for 4 hours to obtain a light yellow transparent macromolecular emulsifier.

[0067] (2) Take 15 parts of the above emulsifier, 40 parts of epoxy resin E-51, and 8 parts of hydrophilic silicone resin and stir them thoroughly in a three-necked flask at 60 degrees. First, slowly add deionized water, then increase the dropwise addition rate to a total of 150 parts of deionized water. Stir and disperse the emulsion at high speed for 40 minutes, then homogenize it in a homogenizer for 30 minutes, and filter it through a gauze to obtain a stable silicone-modified epoxy resin emulsion.

[0068] (3) Take 65 parts of the above emulsion and 5 parts of curing agent and stir and mix them evenly. Then add 75 parts of zinc oxide and stir and mix them evenly to obtain a radiant cooling coating. Apply it on the polyester fabric substrate and cure it at high temperature for 1 hour.

[0069] (4) Take 10 parts of PDMS, 1 part of PDMS curing agent, and 100 parts of tetrahydrofuran, stir thoroughly and dissolve evenly. Then add 20 parts of hydrophobic silica and disperse evenly to obtain a mixed solution. Spray this mixed solution onto the surface of the radiation cooling layer and cure it at high temperature for 1 hour. The hydrophobic radiation cooling coating is obtained, and the final coating amount is 18.7 mg cm -2 .

[0070] (5) Take 100 parts of acrylic emulsion and add 70 parts of copper powder. Disperse evenly to obtain infrared stealth coating. Apply it to the other side of the polyester fabric and cure at high temperature. The coating amount is 20.1 mg·cm -2 The Janus coated fabric with dual functions of infrared stealth, radiation and cooling was obtained.

[0071] Example 6 (1) According to the mass fraction, 400 parts of polyethylene glycol-6000 and 105 parts of epoxy resin E-51 were placed in a three-necked flask, a small amount of cosolvent was added, nitrogen was introduced, and the mixture was stirred at 65°C until the polyethylene glycol and epoxy resin were completely dissolved. 5 parts of potassium persulfate catalyst and a small amount of cosolvent were added and slowly added dropwise to the mixture. The temperature was raised to 180°C and the reaction was carried out for 4 hours to obtain a light yellow transparent macromolecular emulsifier.

[0072] (2) Take 15 parts of the above emulsifier, 40 parts of epoxy resin E-51, and 8 parts of hydrophilic silicone resin and stir them thoroughly in a three-necked flask at 60 degrees. First, slowly add deionized water, then increase the dropwise addition rate to a total of 150 parts of deionized water. Stir and disperse the emulsion at high speed for 40 minutes, then homogenize it in a homogenizer for 30 minutes, and filter it through a gauze to obtain a stable silicone-modified epoxy resin emulsion.

[0073] (3) Take 65 parts of the above emulsion and 5 parts of curing agent and stir and mix them evenly. Then add 85 parts of calcium carbonate and stir and mix them evenly to obtain a radiant cooling coating. Apply it on the polyester fabric substrate and cure it at high temperature for 1 hour.

[0074] (4) Take 10 parts of PDMS, 1 part of PDMS curing agent, and 100 parts of tetrahydrofuran, stir thoroughly and dissolve evenly. Then add 20 parts of hydrophobic silica and disperse evenly to obtain a mixed solution. Spray this mixed solution onto the surface of the radiation cooling layer and cure it at high temperature for 1 hour. The hydrophobic radiation cooling coating is obtained, and the final coating amount is 19.4 mg cm -2 .

[0075] (5) Take 100 parts of silicone emulsion and add 70 parts of copper powder. Disperse evenly to obtain infrared stealth coating. Apply it to the other side of the polyester fabric and cure at high temperature. The coating amount is 19.4 mg·cm -2The Janus coated fabric with dual functions of infrared stealth, radiation and cooling was obtained.

[0076] Figure 1 This is a photograph of the surface water contact angle of the radiation cooling side coating of the infrared stealth radiation cooling dual-function Janus coating fabric prepared in Example 3. The water contact angle is 130.5°, which has good hydrophobicity.

[0077] The radiative cooling performance of the infrared stealth and radiative cooling dual-function Janus-coated fabric prepared in Example 3 was measured using equipment equipped with a thermocouple (PT100 model) and a paperless recorder (SIN-R200F model). The infrared stealth and radiative cooling dual-function Janus-coated fabric and a control PET fabric were placed in a box filled with polystyrene foam and wrapped in aluminum foil. The top of the box was covered with a polyethylene film to prevent heat convection and conduction.

[0078] Figure 2 This is a real-time temperature change curve of the infrared stealth and radiation cooling dual-function Janus coated fabric prepared in Example 3 and the environment. The temperature of the coated fabric is reduced by up to 5.1°C compared to the PET fabric; compared with the air temperature in the box, the coated fabric is cooled by up to 9.8°C, showing excellent radiation cooling performance.

[0079] Figure 3 This is an infrared thermal image of the infrared stealth side of the Janus coated fabric with dual functions of infrared stealth, radiation and cooling prepared in Example 3. The coated fabric was tested for its infrared stealth performance on a 50°C constant temperature heating table. After 20 minutes, its surface temperature was 33.7°C, a decrease of 16.3°C, which can effectively achieve infrared stealth.

[0080] The infrared stealth and radiation cooling dual-function Janus coated fabrics prepared in Examples 1-2 and 4-6 have radiation cooling performance and infrared stealth performance similar to those in Example 3.

[0081] The embodiments described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A coated fabric with both radiative cooling and infrared stealth functions, characterized in that: It includes a fabric base, and a radiation cooling coating and an infrared stealth coating respectively coated on both sides of the fabric base; The radiation cooling coating is a water-based environmentally friendly coating coated with inorganic nanoparticles; The infrared stealth coating is a binder polymer coating coated with reflective particles.

2. The coated fabric with both radiative cooling and infrared stealth functions according to claim 1, characterized in that: Based on the area of the fabric, the coating amount of the infrared stealth coating is 3~20 mg·cm -2 The coating amount of the radiation cooling coating is 2~25 mg·cm -2 .

3. The coated fabric with both radiative cooling and infrared stealth functions according to claim 1, characterized in that: The radiation cooling coating is formed by solidifying an environmentally friendly aqueous emulsion containing inorganic nanoparticles; the environmentally friendly aqueous emulsion contains an emulsifier, a polymer, an organic silicon material, and a catalyst.

4. The coated fabric with both radiative cooling and infrared stealth functions according to claim 3, characterized in that: The emulsifier is formed by polycondensation of a hydrophilic polymer and a lipophilic polymer, wherein the hydrophilic polymer is at least one of polyethylene glycol, polyvinyl alcohol, ethylene oxide propylene oxide copolymer, and polyhydroxyethyl methacrylate; and the lipophilic polymer is an epoxy resin; The polymer is at least one of bisphenol A epoxy resin, alicyclic epoxy resin, and novolac epoxy resin; The organosilicon material is at least one of polyether modified silicone oil, amino silicone oil, phosphate modified silicone oil, carboxyl modified silicone oil, and betaine type silicone; The catalyst is one of triphenylphosphine, dibutyltin dilaurate, potassium persulfate and boron trifluoride etherate.

5. The coated fabric with both radiative cooling and infrared stealth functions according to claim 1, characterized in that: The surface of the radiation cooling coating also has a hydrophobic layer; the hydrophobic layer is an organic silicon polymer layer coated with hydrophobic inorganic particles.

6. The coated fabric with both radiative cooling and infrared stealth functions according to claim 5, characterized in that: The organosilicon polymer is at least one of polydimethylsiloxane, polymethylphenylsiloxane and polyhydrogenmethylsiloxane.

7. The coated fabric with both radiative cooling and infrared stealth functions according to claim 1, characterized in that: The adhesive polymer in the infrared stealth coating is at least one of polyurethane, styrene-butadiene-styrene block copolymer, silicone resin, propylene rubber, epoxy resin and polyethylene.

8. The coated fabric with both radiative cooling and infrared stealth functions according to claim 1, characterized in that: The reflective particles in the infrared stealth coating are at least one of aluminum powder, silver powder, copper powder, indium tin oxide, and nickel powder.

9. A method for preparing a coated fabric having both radiation cooling and infrared stealth functions, characterized in that: The following steps are involved: (1) The hydrophilic polymer and the lipophilic polymer are mixed and stirred uniformly in an inert protective atmosphere, a catalyst is added, and the mixture is reacted at 150-200°C for 1-5 hours to obtain an emulsifier; (2) emulsifying an emulsifier, an organosilicon material, a hydrophilic polymer and deionized water to obtain an organosilicon-modified epoxy resin emulsion; (3) mixing and stirring the silicone-modified epoxy resin emulsion, curing agent, and inorganic nanoparticles, applying the mixture to a fabric substrate, and drying and curing the mixture to obtain a radiant cooling coating; (4) dissolving the organosilicon polymer in an organic solvent, adding hydrophobic inorganic particles to obtain a suspension, and spraying the suspension onto the surface of the radiation cooling coating to obtain a hydrophobic layer; (5) Add reflective particles to the adhesive polymer, stir evenly, and apply them to the other side of the fabric substrate to obtain an infrared stealth coating.

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