A water-based thermal insulation coating and its application in thermal insulation curtains

Abstract

This invention provides a water-based thermal insulation coating and its application in thermal insulation curtains. The water-based thermal insulation coating, by mass fraction, comprises 25-40 wt% elastic acrylic emulsion, 7-18 wt% water-based polyurethane dispersion, 30-40 wt% modified vitrified microspheres, 5-10 wt% nano-titanium dioxide, 1-3 wt% far-infrared radiation filler, 2.5-5.5 wt% additives, and 5-15 wt% water; wherein the modified vitrified microspheres comprise a vitrified microsphere body and a nano-silica transition layer and a flexible buffer shell layer sequentially coating the surface of the vitrified microsphere body. This invention constructs a three-layer shell-core structure of modified vitrified microspheres, creating a chemically active elastic interface layer on the surface of rigid vitrified microspheres. This allows the vitrified microspheres to participate in the cross-linking reaction of the coating resin network through covalent bonds, and eliminates stress concentration between the rigid microspheres and the flexible resin when the coating deforms under stress, effectively preventing cracking and improving flexibility.

Description

Technical Field

[0001] This invention relates to the field of thermal insulation materials technology, specifically to a water-based thermal insulation coating and its application in thermal insulation curtains. Background Technology

[0002] With the increasing demands for building energy conservation and indoor thermal comfort, heat-insulating curtains with solar heat reflection and blocking functions have gradually become a research hotspot. Compared with traditional coated or laminated heat-insulating curtains, the coating method, which directly constructs a heat-insulating functional layer on the fabric surface, has the advantages of flexible processes, controllable costs, and the ability to retain some of the original properties of the fabric. However, there are still some problems in effectively applying heat-insulating coatings to curtain fabrics, which are flexible, deformable, and require frequent use and washing.

[0003] Currently, commercially available thermal insulation coatings are mainly based on rigid substrates such as concrete and metal. Their film-forming materials are mostly hard resins with high glass transition temperatures, and the filler systems primarily consist of rigid hollow glass microspheres and ceramic microspheres. When this type of coating is directly applied to polyester curtain fabrics, adhesion is severely insufficient. Polyester fibers have low surface energy, high crystallinity, and lack reactive polar groups, making it difficult to form an effective interfacial bond using traditional physical adsorption and mechanical intercalation. Furthermore, the significant modulus difference between the rigid coating and the flexible fabric leads to intense application concentration at the interface and within the coating during daily opening, closing, and folding, resulting in large-area cracking and peeling of the coating.

[0004] To improve the flexibility of the coating, elastic acrylic emulsions or waterborne polyurethane are typically used as film-forming materials. However, introducing a high volume fraction of inorganic insulating materials to achieve effective heat insulation drastically degrades the coating's flexibility. Furthermore, existing heat-insulating coatings for curtains often sacrifice the fabric's feel, drape, and aesthetics while achieving insulation. Thick, opaque coatings make curtains stiff and rigid, lacking drape and a skin-friendly feel. Nano-coatings, often used to achieve transparency, often fail to achieve the desired insulation effect. Simultaneously, curtains undergo repeated sun exposure and regular washing. Conventional coatings are prone to yellowing and deterioration under long-term UV exposure, and after multiple washes, they exhibit deterioration in feel, significant reduction in insulation performance, and even coating peeling.

[0005] Therefore, there is an urgent need for a heat-insulating curtain that simultaneously possesses high heat insulation, flexibility and crack resistance, high adhesion, soft feel, and water resistance. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a water-based heat-insulating coating and its application in heat-insulating curtains, thus solving the problems mentioned in the background section.

[0007] To achieve the above objectives, the present invention provides the following technical solution: According to a first aspect of the present invention, an aqueous heat-insulating coating is provided, comprising, by mass fraction, 25-40 wt% of an elastic acrylic emulsion, 7-18 wt% of an aqueous polyurethane dispersion, 30-40 wt% of modified vitrified microspheres, 5-10 wt% of nano-titanium dioxide, 1-3 wt% of far-infrared radiation filler, 2.5-5.5 wt% of additives and 5-15 wt% of water; The modified vitrified microspheres include a vitrified microsphere body and a nano-silica transition layer and a flexible buffer shell layer sequentially coated on the surface of the vitrified microsphere body.

[0008] This application employs modified vitrified microspheres with a surface sequentially coated with a nano-silica transition layer and a flexible buffer shell. The nano-silica transition layer constructs a rough chemically anchored substrate on the surface of the vitrified microspheres, and then a flexible buffer shell is coated onto the surface of the nano-silica transition layer. This creates an elastic interface with a modulus gradient between the rigid vitrified microspheres and the organic resin matrix. When the coating is subjected to bending, stretching, or other external forces, this flexible shell effectively dissipates interfacial stress, preventing interface debonding and crack propagation. Furthermore, the film-forming system selected in this invention, a blend of elastic acrylic emulsion and waterborne polyurethane dispersion, not only ensures the coating's flexibility and elasticity but also guarantees film-forming properties and weather resistance, maintaining excellent flexibility and crack resistance even under high filler loading conditions. Nano-titanium dioxide and far-infrared radiation fillers synergistically enhance the thermal insulation performance with the modified vitrified microspheres.

[0009] Preferably, the modified vitrified microspheres are prepared by the following method: a. Nano-silica is grown in situ on the surface of vitrified microspheres using the sol-gel method to form a nano-silica transition layer; b. Immerse the vitrified microspheres prepared in step a in an ethanol aqueous solution containing vinyltriethoxysilane for surface grafting. c. Disperse the vitrified microspheres prepared in step b in a dispersion of fully soft segment aliphatic polyurethane prepolymer, and spray dry to obtain modified vitrified microspheres.

[0010] In the preparation of modified vitrified microspheres, the nano-silica transition layer prepared by the sol-gel method is mainly used to provide a silanol active layer with nanoscale roughness, increasing the specific surface area and surface energy of the vitrified microspheres. Then, vinyl functional groups are introduced into an ethanol aqueous solution containing vinyltriethoxysilane to enhance the chemical reactivity of the vitrified microspheres. Finally, the vitrified microspheres are coated by spray drying with a dispersion of all-soft-segment aliphatic polyurethane prepolymer. The vinyl functional groups introduced in step b are chemically bonded to the all-soft-segment aliphatic polyurethane prepolymer, improving the stability of the flexible buffer shell.

[0011] Preferably, the concentration of vinyltriethoxysilane in the ethanol-water solution containing vinyltriethoxysilane is 2-5 wt%. The pH of the aqueous ethanol solution containing vinyltriethoxysilane is 4-5.

[0012] By limiting the concentration of vinyltriethoxysilane, this invention can ensure the formation of a monolayer chemical graft on the surface of the nano-silica transition layer. Under pH conditions of 4-5, it can effectively promote the hydrolysis of the siloxy groups of vinyltriethoxysilane to generate active silanol groups, while inhibiting the self-condensation between silanol groups. This allows the coupling agent molecules to undergo dehydration condensation with the hydroxyl groups on the nano-silica layer at a suitable reaction rate, forming a stable Si-O-Si covalently bonded graft layer.

[0013] Preferably, the surface grafting temperature is 70~80℃ and the time is 3~4h.

[0014] Preferably, the solid content in the all-soft segment aliphatic polyurethane prepolymer dispersion is in a mass ratio of 5~15:100 to the vitrified microspheres.

[0015] If the solid content in the all-soft segment aliphatic polyurethane prepolymer dispersion is less than 5%, the resulting flexible buffer shell is too thin and cannot provide sufficient elastic buffer space, resulting in insufficient interfacial stress dissipation capacity. The coating may still develop microcracks when repeatedly bent. On the other hand, if the solid content is too high, the shell will be too thick, which will affect its dispersion uniformity in water-based thermal insulation coatings. Therefore, this application limits the solid content in the all-soft segment aliphatic polyurethane prepolymer dispersion to between 5 and 15 wt%, with 10 wt% being optimal.

[0016] More preferably, the all-soft-segment aliphatic polyurethane prepolymer dispersion further includes an aliphatic polyurethane prepolymer containing disulfide bonds, wherein the mass ratio of the aliphatic polyurethane prepolymer containing disulfide bonds to the all-soft-segment aliphatic polyurethane prepolymer is 1:1.

[0017] This invention adds an aliphatic polyurethane prepolymer containing disulfide bonds to a dispersion of fully soft aliphatic polyurethane prepolymer, enabling the flexible buffer shell on the surface of vitrified microspheres to self-heal cracks through disulfide bond exchange reaction triggered by light or heat when microcracks occur in the coating. This significantly improves the durability and heat insulation performance retention of the coating during long-term bending, washing and aging processes.

[0018] Specifically, the aliphatic polyurethane prepolymer containing disulfide bonds in this invention is prepared by reacting bis(2-hydroxyethyl) disulfide with aliphatic diisocyanate.

[0019] Preferably, the additives include dispersants, defoamers, thickeners, and film-forming aids.

[0020] According to a second aspect of the present invention, an application of a water-based heat-insulating coating in a heat-insulating curtain is provided, wherein the heat-insulating curtain is prepared as follows: S1. Immerse the curtain base fabric in the flexible coating and dry it to obtain a flexible coating. S2. Apply the water-based heat-insulating coating to the surface of the flexible coating, allow it to dry on the surface and then cure it to obtain a heat-insulating layer. S3. Apply a flexible functional coating to the surface of the insulation layer, dry it, and then perform post-treatment to obtain the heat-insulating curtain.

[0021] Preferably, the flexible coating comprises an aqueous polyurethane dispersion, an aqueous acrylate emulsion, and a silane coupling agent, wherein the mass ratio of the aqueous polyurethane dispersion to the aqueous acrylate emulsion is 1:1 to 3. The mass of the silane coupling agent accounts for 0.5-2% of the total solids content of the aqueous polyurethane dispersion and the aqueous acrylic emulsion.

[0022] Preferably, the flexible functional coating comprises, by mass fraction, 90-96 wt% of waterborne polyurethane emulsion, 3-5 wt% of amino silicone oil microemulsion, 1-3 wt% of crosslinking agent and 0.2-0.5 wt% of leveling agent.

[0023] Preferably, the crosslinking agent is selected from carbodiimide or blocked aliphatic isocyanate.

[0024] This invention provides a water-based heat-insulating coating and its application in heat-insulating curtains. It offers the following beneficial effects: (1) The water-based heat insulation coating provided by this solution constructs a modified vitrified microsphere with a three-layer shell-core structure, and constructs a chemically active elastic interface layer on the surface of the rigid vitrified microsphere, so that the vitrified microsphere can participate in the cross-linking reaction of the coating resin network through covalent bonds, and eliminates the stress concentration between the rigid microsphere and the flexible resin when the coating is deformed by force, effectively preventing cracking and improving flexibility.

[0025] (2) The water-based heat insulation coating provided by this solution has a flexible buffer layer on the surface of the vitrified microspheres. As a stress dissipation medium, it effectively eliminates the stress concentration between the rigid microspheres and the flexible resin when the coating is deformed under stress. Under the condition of high filler filling, it still has excellent flexibility and crack resistance.

[0026] (3) The solution provides a water-based heat insulation coating, in which elastic acrylic emulsion and water-based polyurethane are compounded to form a film, providing an elastic carrier for the highly filled functional filler. Modified vitrified microspheres bear the responsibility of solar heat reflection and heat conduction barrier, and nano titanium dioxide assists in enhancing visible light and near-infrared scattering reflection. Together with far-infrared radiation filler, it achieves a highly efficient heat insulation effect.

[0027] (4) The application of a water-based heat insulation coating in heat insulation curtains provided by this solution is that the flexible coating in contact with the curtain base fabric is chemically anchored by the hydrogen bonds of water-based polyurethane and the silane coupling agent, which firmly locks the flexible coating onto the smooth curtain base fabric. The water-based heat insulation coating is applied to the surface of the flexible coating, and finally the flexible functional coating is applied to the surface of the heat insulation layer. The crosslinking agent and the silane coupling agent work together to build a chemical crosslinking and physical interpenetration network that runs through the layers in the coating system, which can significantly improve the anti-fall-off property and avoid the decay of heat insulation performance. Detailed Implementation

[0028] To better illustrate the content of this invention, the following description is provided in conjunction with specific embodiments.

[0029] Example 1 Preparation of modified vitrified microspheres: a. 100g of vitrified microspheres with a particle size of 20~80μm were dispersed in 500mL of ethanol aqueous solution, 3.5g of tetraethyl silane was added, and the pH of the system was adjusted to 9.0 under the catalysis of ammonia water. The mixture was stirred continuously at 50℃ for 6h. After the reaction was completed, the mixture was filtered, washed three times with anhydrous ethanol, and dried at 80℃ for 4h to grow roughened vitrified microspheres with a nano silica transition layer on the surface. b. Dissolve 4.0 g of vinyltriethoxysilane in 100 mL of ethanol aqueous solution, adjust the pH to 4.5 with acetic acid, hydrolyze at room temperature for 30 min to obtain a coupling agent pre-hydrolyzed solution, immerse the roughened vitrified microspheres in the pre-hydrolyzed solution, heat to 75 °C, stir and react for 3 h, wash repeatedly with anhydrous ethanol after the reaction, filter, and vacuum dry at 80 °C to obtain surface vinyl functionalized active vitrified microspheres. c. Disperse 100g of active vitrified microspheres in an aqueous dispersion of 200g of aliphatic polyurethane prepolymer (Tg=-35℃) containing 10g of solids. After thorough mixing, dry and granulate using a spray drying agent with an inlet air temperature of 140℃ and an outlet air temperature of 65℃ to obtain modified vitrified microspheres with a flexible buffer shell. Preparation of water-based heat-insulating coatings: By mass fraction, 33 wt% of elastic acrylic emulsion, 15 wt% of waterborne polyurethane dispersion, 34 wt% of modified vitrified microspheres, 7 wt% of rutile nano-titanium dioxide, 1.5 wt% of far-infrared ceramic powder, 0.8 wt% of ammonium polyacrylate dispersant, 0.2 wt% of mineral oil defoamer, 0.5 wt% of polyurethane associative thickener, 2.0 wt% of alcohol ester twelve film-forming aid, and 6.0 wt% of water are uniformly dispersed in a high-speed dispersant to obtain a waterborne heat-insulating coating.

[0030] Example 2 The preparation method of this embodiment is the same as that of Example 1, except that the concentration of vinyltriethoxysilane is 2wt% in the preparation of the modified vitrified microspheres.

[0031] Example 3 The preparation method of this embodiment is the same as that of Example 1, except that the mass ratio of the solid content in the all-soft segment fatty polyester prepolymer dispersion to the active vitrified microspheres is 5:1 during the preparation of the modified vitrified microspheres.

[0032] Example 4 The preparation method of this embodiment is the same as that of Example 1, except that the solid content in the all-soft segment fatty polyester prepolymer dispersion and the mass ratio of the active vitrified microspheres in the preparation process of the modified vitrified microspheres are 15:1.

[0033] Example 5 The preparation method of this embodiment is the same as that of Example 1. The difference is that in the preparation process of the modified vitrified microspheres, an aliphatic polyurethane prepolymer containing disulfide bonds is added to the dispersion of the all-soft segment fatty polyester prepolymer. The mass ratio of the aliphatic polyurethane prepolymer containing disulfide bonds to the all-soft segment fatty polyester prepolymer is 1:1.

[0034] Example 6 The preparation method of this embodiment is the same as that of Example 1, except that, in the preparation process of the water-based heat insulation coating, by mass fraction, it includes 25wt% elastic acrylic emulsion, 7wt% water-based polyurethane dispersion, 30wt% modified vitrified microspheres, 5wt% rutile nano titanium dioxide, 1wt% far-infrared ceramic powder, 0.5wt% ammonium polyacrylate dispersant, 0.1wt% mineral oil defoamer, 0.2wt% polyurethane associative thickener, 2wt% alcohol ester twelve film-forming aid and 29.2wt% water.

[0035] Example 7 The preparation method of this embodiment is the same as that of Example 1, except that, in the preparation process of the water-based heat insulation coating, by mass fraction, it includes 35wt% elastic acrylic emulsion, 15wt% water-based polyurethane dispersion, 40wt% modified vitrified microspheres, 5wt% rutile nano titanium dioxide, 1wt% far-infrared ceramic powder, 1wt% ammonium polyacrylate dispersant, 0.5wt% mineral oil defoamer, 0.2wt% polyurethane associative thickener, 0.5wt% alcohol ester twelve film-forming aid and 1.8wt% water.

[0036] Comparative Example 1 The preparation method of this comparative example is the same as that of Example 1, except that the vitrified microspheres were not treated in any way and were directly added to the water-based heat insulation coating with a particle size of 20~80μm.

[0037] Comparative Example 2 The comparative example is prepared using the same method as Example 1, except that a nano-silica layer is grown in situ only on the surface of the vitrified microspheres, without surface grafting or flexible polymer coating.

[0038] Comparative Example 3 The comparative example is prepared using the same method as Example 1, except that only the nano-silica layer is prepared and surface grafted on the surface of the vitrified microspheres, without flexible polymer coating.

[0039] Comparative Example 4 The comparative example was prepared using the same method as Example 1, except that the concentration of vinyltriethoxysilane was 1.5 wt% during the preparation of the modified vitrified microspheres.

[0040] Comparative Example 5 The preparation method of this comparative example is the same as that of Example 1, except that the concentration of vinyltriethoxysilane is 5 wt% in the preparation of the modified vitrified microspheres.

[0041] Comparative Example 6 The preparation method of this comparative example is the same as that of Example 1, except that the mass ratio of the solid content in the all-soft segment fatty polyester prepolymer dispersion to the active vitrified microspheres is 3:1 during the preparation of the modified vitrified microspheres.

[0042] Comparative Example 7 The preparation method of this comparative example is the same as that of Example 1, except that the mass ratio of the solid content in the all-soft segment fatty polyester prepolymer dispersion to the active vitrified microspheres is 20:1 during the preparation of the modified vitrified microspheres.

[0043] Application Examples 1-7 The water-based heat-insulating coatings prepared according to Examples 1 to 7 are applied in the preparation process of heat-insulating curtains. The specific preparation process is as follows: Step 1: Mix the waterborne polyurethane dispersion and the waterborne acrylic emulsion at a solids mass ratio of 1:2, add 1.0 wt% of silane coupling agent KH-560, and stir until homogeneous to prepare a flexible primer coating. The coating weight is 80 g / m². 2 The polyester plain weave curtain base fabric is immersed in a flexible primer coating with a roll-off rate of 60% and dried with hot air at 100°C to form a flexible primer coating with a dry film thickness of approximately 8μm. Step 2: Apply the water-based heat insulation coatings prepared in Examples 1-6 evenly to the surface of the flexible base layer by scraping, control the dry film thickness to 45 μm, surface dry at 70℃ for 15 min, then heat up to 130℃ for 3 min to cure, forming a heat insulation layer. Step 3: Take 96 wt% of polyether-type waterborne polyurethane emulsion (Tg=-42℃), 3 wt% of reactive amino silicone oil microemulsion, 1 wt% of carbodiimide crosslinking agent, 0.2 wt% of polyether-modified organosilicon leveling agent, and the balance water and stir evenly to obtain a flexible functional coating. Apply the flexible functional coating to the surface of the heat insulation layer by kissing method, control the wet film thickness to 25 μm, and after coating, the curtain is put into the hot air drying tunnel for drying and curing to obtain a flexible functional layer with a dry film thickness of 10 μm, thus completing the preparation of the heat insulation curtain.

[0044] Application Comparative Examples 1-7 The preparation methods in Comparative Examples 1-7 are the same as those in Application Examples 1-7, except that in step 2, the water-based heat-insulating coatings prepared in Examples 1-7 are replaced with the water-based heat-insulating coatings prepared in Comparative Examples 1-7.

[0045] Comparative Application Example 8 The preparation method of this application example is the same as that of application examples 1 to 6, except that the preparation of the flexible base coating in step 1 is omitted.

[0046] Comparative Application Example 9 The preparation method of this application example is the same as that of application examples 1 to 6, except that the preparation of the flexible functional layer in step 3 is omitted.

[0047] The performance of the heat-insulating curtain samples prepared in Application Examples 1-7 and Comparative Examples 1-9 above was tested, and the test methods are as follows: Thermal insulation test: The solar reflectance was tested according to the test standard GB / T 2680-2021; the thermal conductivity of the coating was tested according to ASTM C518 "Standard Test Method for Determination of Thermal Conductivity by Steady Heat Flow". Flexibility test: With the coating of the heat insulation curtain sample facing outward, bend it repeatedly 100,000 times around a 2mm diameter rod to simulate the daily opening and closing of the curtain. Use a magnifying glass to observe the formation of oil stains and cracks on the coating surface, record the number of bends that first cause cracks to appear, and evaluate the crack level. Adhesion test: The ease with which the coating adheres to the glass from the base fabric is evaluated according to the tape slap test method in AATCC TM8 "Rubbing Discoloration Test Method"; Washability test: According to GB / T 8629-2017 "Home Washing and Drying Procedures for Textile Testing", the product was washed 30 times at 40℃, and air-dried after each wash. After washing, the solar reflectance was tested again, the heat insulation performance retention rate was calculated, and the appearance after washing was observed.

[0048] The specific test results are shown in Table 1.

[0049] Table 1

[0050] According to the data in Table 1, the solar reflectance of Application Examples 1 to 6 is between 82% and 87%, and the thermal conductivity is between 0.071 and 0.080 W / (m·K). Compared with other application examples, Application Example 1 has better performance, with excellent flexibility, adhesion and water resistance.

[0051] Comparing Comparative Example 1 with Application Example 1, it can be seen that although the initial thermal insulation performance of the vitrified microspheres was similar to that of Application Example 1, the flexibility and water washability were significantly different. Comparing Application Example 2 with Application Example 1, it can be seen that simply increasing the surface roughness of the vitrified microspheres increases the surface area of ​​the vitrified microspheres and enhances the physical interlocking effect. However, after bending, Raed patterns still appear, and the water washing retention rate is low, still far lower than that of the application example. Comparative Example 3 shows that vinyl groups were grafted onto the surface of the nano-silica layer. The microspheres can be cross-linked with the resin network through a process. After bending, the cracks are reduced and the water washing retention rate is increased to 72.1%. However, there is still a problem of modulus matching between the rigid vitrified microspheres and the resin. Stress will concentrate at the interface, and the retention rate is still insufficient after long-term service. In Comparative Examples 4-5, if the amount of vinyltriethoxysilane used is too low, more microcracks will appear and the water washability will decrease. If the amount of vinyltriethoxysilane used is too high, the heat insulation effect, flexibility and water washability are excellent, but the improvement effect is not obvious compared with Application Example 1. From the perspective of cost control, the amount of vinyltriethoxysilane used is better at 2~5wt%. In Comparative Examples 6-7, the amount of fully soft aliphatic polyurethane prepolymer used was too low, resulting in microcracks after bending and peeling after washing, with a low retention rate. However, when the amount of fully soft aliphatic polyurethane prepolymer used was too high, the test results were good, but in the actual preparation process, the modified vitrified microspheres would stick together when dispersed in the coating, affecting storage stability. As can be seen from the comparison between Application Examples 8-9 and Application Example 1, the flexible base layer provides an anchoring foundation and stress buffer, while the flexible functional layer serves as a protective barrier and tactile interface. These two layers work together with the thermal insulation layer, and the absence of either layer will lead to a reduction in the overall performance of the thermal insulation curtain.

[0052] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A water-based heat-insulating coating, characterized in that: By mass fraction, it includes 25-40 wt% elastic acrylic emulsion, 7-18 wt% aqueous polyurethane dispersion, 30-40 wt% modified vitrified microspheres, 5-10 wt% nano titanium dioxide, 1-3 wt% far-infrared radiation filler, 2.5-5.5 wt% additives and 5-15 wt% water. The modified vitrified microspheres include a vitrified microsphere body and a nano-silica transition layer and a flexible buffer shell layer sequentially coated on the surface of the vitrified microsphere body.

2. The water-based heat-insulating coating according to claim 1, characterized in that: The modified vitrified microspheres were prepared by the following method: a. Nano-silica is grown in situ on the surface of vitrified microspheres using the sol-gel method to form a nano-silica transition layer; b. Immerse the vitrified microspheres prepared in step a in an ethanol aqueous solution containing vinyltriethoxysilane for surface grafting. c. Disperse the vitrified microspheres prepared in step b in a dispersion of fully soft segment aliphatic polyurethane prepolymer, and spray dry to obtain modified vitrified microspheres.

3. The water-based heat-insulating coating according to claim 2, characterized in that: The concentration of vinyltriethoxysilane in the ethanol-water solution containing vinyltriethoxysilane is 2-5 wt%; The pH of the aqueous ethanol solution containing vinyltriethoxysilane is 4-5.

4. The water-based heat-insulating coating according to claim 2, characterized in that: The surface grafting temperature is 70~80℃, and the time is 3~4h.

5. The water-based heat-insulating coating according to claim 2, characterized in that: The solid content of the fully soft segment aliphatic polyurethane prepolymer dispersion is in a mass ratio of 5~15:100 to the vitrified microspheres.

6. The water-based heat-insulating coating according to claim 2, characterized in that: The all-soft-segment aliphatic polyurethane prepolymer dispersion also includes an aliphatic polyurethane prepolymer containing disulfide bonds, wherein the mass ratio of the aliphatic polyurethane prepolymer containing disulfide bonds to the all-soft-segment aliphatic polyurethane prepolymer is 1:

1.

7. The water-based heat-insulating coating according to claim 1, characterized in that: The additives include dispersants, defoamers, thickeners, and film-forming aids.

8. The application of the water-based heat-insulating coating according to any one of claims 1 to 7 in heat-insulating curtains, characterized in that: The method for preparing the heat-insulating curtain is as follows: S1. Immerse the curtain base fabric in the flexible coating and dry it to obtain a flexible coating. S2. Apply the water-based heat-insulating coating to the surface of the flexible coating, allow it to dry on the surface and then cure it to obtain a heat-insulating layer. S3. Apply a flexible functional coating to the surface of the insulation layer, dry it, and then perform post-treatment to obtain the heat-insulating curtain.

9. An application according to claim 8, characterized in that: The flexible coating comprises an aqueous polyurethane dispersion, an aqueous acrylic emulsion, and a silane coupling agent, wherein the mass ratio of the aqueous polyurethane dispersion to the aqueous acrylic emulsion is 1:1 to 3. The mass of the silane coupling agent accounts for 0.5-2% of the total solids content of the aqueous polyurethane dispersion and the aqueous acrylic emulsion.

10. An application according to claim 8, characterized in that: The flexible functional coating comprises, by mass fraction, 90-96 wt% of an aqueous polyurethane emulsion, 3-5 wt% of an amino silicone oil microemulsion, 1-3 wt% of a crosslinking agent and 0.2-0.5 wt% of a leveling agent, wherein the crosslinking agent is selected from carbodiimide or blocked aliphatic isocyanate.

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