Preparation method of self-cleaning nano transparent heat insulation coating

Abstract

The application relates to the technical field of glass coating, and particularly discloses a preparation method of a self-cleaning nano transparent heat-insulating coating, which comprises the following steps: S1, preparing an acidic aqueous solution and adding polyoxyethylene dinonyl phenyl ether and graphene; S2, adding a titanate, a zinc alcoholate, an aluminum alcoholate and a siloxane into the acidic aqueous solution and reacting to obtain a transparent composite nano sol; S3, spraying the transparent composite nano sol to the surface of a transparent base material to form a primary coating; and S4, spraying a dilute alkaline solution to the primary coating, so that the components in the primary coating are condensed and crosslinked, and a transparent nano film is generated in situ on the surface of the transparent base material. The self-cleaning nano transparent heat-insulating coating prepared by the above preparation method has excellent visible light transmittance, and the durability, weather resistance, heat-insulating efficiency and surface self-cleaning capacity are all significantly improved, so that the purposes of energy saving and water saving, carbon reduction and environmental protection are achieved.

Description

Technical Field

[0001] This invention relates to the field of glass coating technology, and in particular to a method for preparing a self-cleaning nano-transparent heat-insulating coating. Background Technology

[0002] With the long-term reliance on traditional energy sources such as coal and oil, energy shortages and environmental pollution have become two major pressing issues in contemporary social development. In addition to accelerating the development of new energy sources, countries are also seeking more effective methods to reduce energy consumption and pollution emissions. Solar radiation, especially infrared radiation, generates a large amount of heat, which significantly impacts people's lives and production, particularly in fields such as construction and automobiles where the extensive use of transparent glass materials exacerbates energy consumption. To reduce the impact of solar heat radiation on daily life and production, people widely use refrigeration equipment, leading to ever-increasing energy consumption and exacerbating greenhouse gas emissions. Thermal insulation materials, due to their ability to block heat conduction, can effectively reduce internal temperatures when applied to the exterior surfaces of buildings or automobiles, reducing the need for refrigeration equipment and thus contributing to energy conservation and emission reduction. How to more conveniently, effectively, and sustainably insulate against solar heat radiation without reducing the light transmittance of materials such as glass has been a problem that researchers in related fields have been striving to solve.

[0003] Traditionally, there are two main approaches to solving the heat insulation problem of transparent substrates such as glass. One approach is to use heat-insulating films applied to the glass. While these films offer some insulation, they also have many drawbacks. For example, their transparency is insufficient, obstructing visibility; they are prone to aging under sunlight, leading to cracking, blistering, and peeling; they are expensive but have a short lifespan; and these films and the adhesives they use release volatile organic compounds (VOCs) such as formaldehyde, benzene, and toluene, which are harmful to health; discarded films are difficult to degrade, further contributing to environmental pollution. The other approach is to use heat-insulating coatings. This involves dispersing heat-insulating powders such as antimony tin dioxide (ATO), indium tin oxide (ITO), or lanthanum hexaboride (LaB6) into a transparent resin (e.g., waterborne polyurethane (WPU)), and then coating this coating onto the surface of the glass substrate to form a heat-insulating layer. Although this method has seen some development, the market has not yet gained significant acceptance for these products, and their practical application is limited. The main reasons for this are as follows: First, these powder materials have inherent colors, which affect transparency and appearance. Second, these heavy metal oxide powder materials are prone to agglomeration, making uniform dispersion difficult. Their density differs significantly from the resin, leading to sedimentation and poor stability. In practical use, this results in noticeable, visually unappealing "nodules" on the substrate surface, and coating uniformity is difficult to control. Third, the hardness, aging resistance, wear resistance, and water resistance of this resin coating are poor. Aging resistance is particularly problematic because the inorganic powder materials absorb infrared radiation, causing a significant increase in the coating's temperature, making the resin in the coating more susceptible to slow thermal aging. Furthermore, if the coating is applied to the outside of a substrate such as glass, its ability to withstand rainwater immersion is poor, leading to cracks, blistering, and even delamination, resulting in poor weather resistance. Therefore, developing a new, more effective, and weather-resistant transparent heat-insulating coating is essential. Summary of the Invention

[0004] Therefore, it is necessary to provide a method for preparing a self-cleaning nano-transparent thermal insulation coating to address the above-mentioned shortcomings. The self-cleaning nano-transparent thermal insulation coating prepared by this method has excellent visible light transmittance, and its durability, weather resistance, thermal insulation efficiency and surface self-cleaning ability are significantly improved, thus achieving the goals of energy saving, water saving, carbon reduction and environmental protection.

[0005] A method for preparing a self-cleaning nano-transparent heat-insulating coating includes the following steps:

[0006] S1: Prepare an acidic aqueous solution and add polyoxyethylene dinonylphenyl ether and graphene;

[0007] S2: Add titanate, zinc alkoxide, aluminum alkoxide and siloxane to an acidic aqueous solution and react to obtain a transparent composite nanosol;

[0008] S3: Spray the transparent composite nanosol onto the surface of a transparent substrate to form a primary coating;

[0009] S4: Spray a dilute alkaline solution onto the primary coating to cause the components in the primary coating to condense and crosslink, and to generate a transparent nanofilm in situ on the surface of the transparent substrate.

[0010] In one embodiment, the mass fraction of each component in the acidic aqueous solution is: 0.05-0.1% polyoxyethylene dinonylphenyl ether, 0.001-0.01% graphene, 2-3% titanate, 0.5-2% zinc alkoxide, 0.5-2% aluminum alkoxide, 1-3% siloxane, and the balance being acid and water.

[0011] In one embodiment, the titanate is at least one of ethyl titanate, butyl titanate, or tetraisopropyl titanate; the zinc alkoxide is at least one of 2-methoxyethoxyzinc, diisopropoxyzinc, or diethoxyzinc; the aluminum alkoxide is at least one of aluminum isopropoxide or aluminum triethoxy; and the siloxane is at least one of tetraethoxysilane, tetramethoxysilane, or 3-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0012] In one embodiment, the graphene is acidified monolayer graphene with a lateral dimension of 100-400 nm.

[0013] In one embodiment, the acidic aqueous solution is obtained by diluting at least one of acetic acid, hydrochloric acid, or nitric acid with distilled water, and the pH value of the acidic aqueous solution is 1-3.

[0014] In one embodiment, the dilute alkaline solution is obtained by diluting at least one of sodium hydroxide, potassium hydroxide, or ammonia water with distilled water, and the pH value of the dilute alkaline solution is 10-12.

[0015] In one embodiment, the reaction temperature in step S2 is 50-90°C, the reaction time is 4-6 hours, and the reaction is continuously stirred during the process.

[0016] In one embodiment, in steps S3 and S4, the spraying equipment is an electric nano-atomizing spray gun, the spraying distance is 10-30 cm, and the spraying amount is 30-50 grams of liquid per square meter.

[0017] The preparation method of the self-cleaning nano-transparent heat-insulating coating of the present invention involves hydrolyzing and condensing precursors such as titanate, zinc alkoxide, aluminum alkoxide, and siloxane to obtain a composite nano-coating of titanium dioxide, zinc oxide, aluminum oxide, and polysiloxane. Utilizing the infrared and ultraviolet absorption capabilities of these nano-oxides, along with the quantum synergistic effect of graphene, the coating achieves heat insulation and ultraviolet shielding. The polyhydroxy polysiloxane and titanium dioxide composite coating exhibits excellent hydrophilicity, giving the treated surface a superhydrophilic effect, which is beneficial for natural rainwater infiltration and automatic surface cleaning. The graphene-containing composite nano-coating also has antistatic effects, reducing dust adsorption. Combined with the superhydrophilic and easy-to-clean surface characteristics, it reduces cleaning steps and water usage. This composite nano-coating is generated and cross-linked in situ on the treated surface, resulting in better uniformity, density, and stronger adhesion, and is washable. As an inorganic self-crosslinking system, this composite nano-coating does not use easily aging resins, adhesives, or polymer films, thus exhibiting better weather resistance. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating a method for preparing a self-cleaning nano-transparent heat-insulating coating in one embodiment of the present invention. Detailed Implementation

[0019] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0020] This invention discloses a method for preparing a self-cleaning nano-transparent heat-insulating coating. The method uses titanate, zinc alkoxide, aluminum alkoxide, and siloxane as precursors, trace amounts of graphene as additives, and polyoxyethylene dinonylphenyl ether as a stabilizer. The titanate, zinc alkoxide, aluminum alkoxide, and siloxane are hydrolyzed in an acidic aqueous solution to obtain a transparent composite nanosol. The obtained nanosol is then uniformly sprayed onto the surface of a transparent substrate such as glass. After natural drying, a layer of dilute alkaline solution is sprayed on, further condensing and cross-linking the components in the coating. Finally, a dense transparent nanofilm is formed in situ on the substrate surface. The resulting transparent nanofilm possesses heat insulation, UV protection, and self-cleaning properties, which are beneficial for energy and water conservation, carbon reduction, and environmental protection. It also has advantages such as weather resistance and scrub resistance.

[0021] When preparing a self-cleaning nano-transparent heat-insulating coating using the above method, traditional heavy metal powder materials containing inherent colors such as ATO, ITO, or LaB6 are not used. This avoids affecting the coating's transparency and prevents problems such as agglomeration and dispersion difficulties. The composite nano-coating material prepared by this invention is environmentally friendly, safe, and has a simple processing technology. It can be applied at room temperature through two simple spraying and drying processes, making it particularly suitable for large-scale applications. After self-crosslinking and film formation, it is transparent and has excellent adhesion, heat insulation performance, UV protection performance, and hydrophilic and easy-to-clean properties. In addition, the nano-titanium dioxide and zinc oxide in the coating also have the self-cleaning ability to photocatalytically decompose organic stains and microorganisms on the substrate surface under light. While ensuring excellent visible light transmittance, it improves the heat insulation efficiency, durability, and easy-to-clean and self-cleaning ability of transparent materials such as glass, achieving the goals of energy saving, water saving, carbon reduction, and environmental protection.

[0022] For details, please refer to Figure 1 The preparation method of the self-cleaning nano-transparent heat-insulating coating in this embodiment includes the following steps:

[0023] S1: Prepare an acidic aqueous solution and add polyoxyethylene dinonylphenyl ether and graphene.

[0024] In this embodiment, the acidic aqueous solution is obtained by diluting at least one of acetic acid, hydrochloric acid, or nitric acid with distilled water, and the pH value of the acidic aqueous solution is 1-3. After polyoxyethylene dinonylphenyl ether and graphene are added to the acidic aqueous solution, they need to be stirred continuously for a period of time to ensure that the polyoxyethylene dinonylphenyl ether and graphene are mixed evenly in the acidic aqueous solution.

[0025] Furthermore, in this embodiment, the graphene is acidified single-layer graphene with a lateral dimension of 100-400 nm, and the molecular formula of polyoxyethylene dinonylphenyl ether is C 25 H 44 O6.

[0026] S2: Add titanate, zinc alkoxide, aluminum alkoxide and siloxane to an acidic aqueous solution and react to obtain a transparent composite nanosol.

[0027] In this embodiment, the titanate is at least one of ethyl titanate, butyl titanate, or tetraisopropyl titanate; the zinc alkoxide is at least one of 2-methoxyethoxyzinc, diisopropoxyzinc, or diethoxyzinc; the aluminum alkoxide is at least one of aluminum isopropoxide or aluminum triethoxy; and the siloxane is at least one of tetraethoxysilane, tetramethoxysilane, or 3-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0028] Furthermore, in the acidic aqueous solution, the mass fractions of each component are as follows: polyoxyethylene dinonylphenyl ether 0.05-0.1%, graphene 0.001-0.01%, titanate 2-3%, zinc alkoxide 0.5-2%, aluminum alkoxide 0.5-2%, siloxane 1-3%, and the balance being acid and water.

[0029] The purpose of steps S1 and S2 is to prepare a transparent composite nanosol, which can be obtained by a low-temperature bath sol-gel technique. In this embodiment, the raw materials are first dispersed in water, and an acidic environment is provided to hydrolyze precursors such as titanate, zinc alkoxide, aluminum alkoxide, and siloxane in the acidic aqueous solution, generating alkoxy-active monomers such as hydroxytitanium, hydroxyzinc, hydroxyaluminum, and hydroxysilane. Each precursor undergoes a hydrolysis reaction according to the following general formula:

[0030] Hydrolysis reaction: M(OR) n +xH₂O→M(OH) x (OR) n-x +xROH

[0031] Polyoxyethylene dinonylphenyl ether is used as a stabilizer to ensure the stability of the hydrolysis products. The reaction temperature in step S2 is 50-90℃ and the reaction time is 4-6h. The reaction is continuously stirred to ensure that each precursor is fully hydrolyzed.

[0032] S3: A transparent composite nano-sol is sprayed onto the surface of a transparent substrate to form a primary coating. This primary coating is obtained by spraying the transparent composite nano-sol onto the surface of the transparent substrate and then allowing it to dry naturally.

[0033] S4: A dilute alkaline solution is sprayed onto the primary coating to cause the components in the primary coating to condense and crosslink, forming a dense, transparent nanofilm in situ on the surface of the transparent substrate. Step S4 aims to induce polycondensation of the active monomers under alkaline conditions, thereby generating a gel with a specific spatial structure. The active monomers undergo polymerization reactions according to the following general formula:

[0034] Polymerization reaction: -M-OH + HO-M- → -MOM- + H2O

[0035] That is, alkoxyl-active monomers such as titanium hydroxyl, zinc hydroxyl, aluminum hydroxyl, and silicon hydroxyl undergo condensation polymerization under alkaline conditions to form condensation polymers such as titanium oxide, zinc oxide, aluminum oxide, and silicon oxide. After drying and dehydration, they form a composite nano-oxide particle layer, i.e., a transparent nanofilm.

[0036] In this embodiment, the dilute alkaline solution is obtained by diluting at least one of sodium hydroxide, potassium hydroxide, or ammonia water with distilled water, and the pH value of the dilute alkaline solution is 10-12. Further, in steps S3 and S4, the spraying equipment is an electric nano-atomizing spray gun, the spraying distance is 10-30 cm, and the spraying amount is 30-50 grams of liquid per square meter to ensure a uniform coating.

[0037] The purpose of steps S3 and S4 is to spray the substrate with the composite nanosol prepared in steps S1 and S2.

[0038] The process of preparing a self-cleaning nano-transparent heat-insulating coating using the above method will be explained below with specific examples.

[0039] Example 1

[0040] At room temperature, adjust 500 ml of distilled water to pH 1 using a mixture of hydrochloric acid and acetic acid. Add 0.3 g of dinonylphenyl ether and 10 mg of acidified monolayer graphene, and stir until homogeneous. Then, while stirring, add 12 g of tetraisopropyl titanate, 6 g of zinc diethoxy, 6 g of aluminum isopropoxide, and 10 g of tetraethoxysilane dropwise. After the addition is complete, stir the reaction mixture at 50-90℃ for 4-6 hours to obtain a transparent composite nanosol.

[0041] The obtained transparent composite nanosol was loaded into an electric nano-atomizing spray gun. The atomization effect was adjusted, and the mixture was evenly sprayed onto a 5mm thick transparent glass that had been cleaned beforehand at a distance of 10-30cm. After it dried naturally, a layer of dilute ammonia solution with a pH of 10-12 was sprayed on, and the mixture was left to stand for 6-12 hours.

[0042] Example 2

[0043] At room temperature, adjust the pH of 500 ml distilled water to 1 with nitric acid, add 0.5 g of polyoxyethylene dinonylphenyl ether and 10 mg of acidified monolayer graphene, and stir until homogeneous. Then, while stirring, add 15 g of ethyl titanate, 9 g of 2-methoxyethoxyzinc, 6 g of triethoxyaluminum, 8 g of tetraethoxysilane, and 4 g of 3-(2,3-epoxypropoxy)propyltrimethoxysilane dropwise. After the addition is complete, stir the reaction at 50-90℃ for 4-6 h to obtain a transparent composite nanosol.

[0044] The obtained transparent composite nanosol is loaded into an electric nano-atomizing spray gun. The atomization effect is adjusted, and the mixture is evenly sprayed onto a pre-cleaned 5mm thick transparent glass at a distance of 10-30cm. After natural drying, a layer of dilute sodium hydroxide solution with a pH of 10-12 is sprayed on, and then left to stand for 6-12 hours.

[0045] The glass treated by the methods in Examples 1 and 2 was subjected to performance tests, and the results are shown in the table below:

[0046] project Visible light transmittance (%) UV shielding rate (%) Wetting angle (°) Membrane hardness (H) Example 1 90 92 2 7 Example 2 88 96 1 7

[0047] As can be seen, in Example 1, the visible light transmittance of the treated glass was measured to be 90%, the ultraviolet shielding rate was 92%, the wetting angle (water contact angle) was 2°, and the film hardness was 7H; in Example 2, the visible light transmittance of the treated glass was measured to be 88%, the ultraviolet shielding rate was 96%, the wetting angle (water contact angle) was 1°, and the film hardness was 7H.

[0048] A blank glass (ordinary transparent glass without a heat-insulating coating) was used as a control group. Compared with the blank glass, the glass treated in Example 1 showed a temperature difference of 7 degrees Celsius under simulated solar infrared radiation. After 480 hours of accelerated aging testing, the appearance and color of the film remained unchanged. The glass treated in Example 1 showed a temperature difference of 9 degrees Celsius under simulated solar infrared radiation. After 480 hours of accelerated aging testing, the appearance and color of the film remained unchanged.

[0049] The preparation method of the self-cleaning nano-transparent heat-insulating coating of the present invention involves hydrolyzing and condensing precursors such as titanate, zinc alkoxide, aluminum alkoxide, and siloxane to obtain a composite nano-coating of titanium dioxide, zinc oxide, aluminum oxide, and polysiloxane. Utilizing the infrared and ultraviolet absorption capabilities of these nano-oxides, along with the quantum synergistic effect of graphene, the coating achieves heat insulation and ultraviolet shielding. The polyhydroxy polysiloxane and titanium dioxide composite coating exhibits excellent hydrophilicity, giving the treated surface a superhydrophilic effect, which is beneficial for natural rainwater infiltration and automatic surface cleaning. The graphene-containing composite nano-coating also has antistatic effects, reducing dust adsorption. Combined with the superhydrophilic and easy-to-clean surface characteristics, it reduces cleaning steps and water usage. This composite nano-coating is generated and cross-linked in situ on the treated surface, resulting in better uniformity, density, and stronger adhesion, and is washable. As an inorganic self-crosslinking system, this composite nano-coating does not use easily aging resins, adhesives, or polymer films, thus exhibiting better weather resistance.

[0050] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0051] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing a self-cleaning nano-transparent heat-insulating coating, characterized in that, Includes the following steps: S1: Prepare an acidic aqueous solution and add polyoxyethylene dinonylphenyl ether and graphene. The mass fraction of titanate in the acidic aqueous solution is 2-3%. S2: Add titanate, zinc alkoxide, aluminum alkoxide and siloxane to an acidic aqueous solution and react to obtain a transparent composite nanosol; S3: The transparent composite nano-sol is sprayed onto the surface of a transparent substrate to form a primary coating. This primary coating is obtained by spraying the transparent composite nano-sol onto the surface of the transparent substrate and then allowing it to dry naturally. S4: Spray a dilute alkaline solution onto the primary coating to cause the components in the primary coating to condense and crosslink, and to generate a transparent nanofilm in situ on the surface of the transparent substrate.

2. The preparation method according to claim 1, characterized in that, In the acidic aqueous solution, the mass fractions of each component are as follows: polyoxyethylene dinonylphenyl ether 0.05-0.1%, graphene 0.001-0.01%, zinc alkoxide 0.5-2%, aluminum alkoxide 0.5-2%, siloxane 1-3%, and the balance being acid and water.

3. The preparation method according to claim 2, characterized in that, The titanate is at least one of ethyl titanate, butyl titanate, or tetraisopropyl titanate; the zinc alkoxide is at least one of 2-methoxyethoxyzinc, diisopropoxyzinc, or diethoxyzinc; the aluminum alkoxide is at least one of aluminum isopropoxide or aluminum triethoxy; and the siloxane is at least one of tetraethoxysilane, tetramethoxysilane, or 3-(2,3-epoxypropoxy)propyltrimethoxysilane.

4. The preparation method according to claim 3, characterized in that, The graphene is acidified monolayer graphene with a lateral dimension of 100-400 nm.

5. The preparation method according to claim 4, characterized in that, The acidic aqueous solution is obtained by diluting at least one of acetic acid, hydrochloric acid or nitric acid with distilled water, and the pH value of the acidic aqueous solution is 1-3.

6. The preparation method according to claim 5, characterized in that, The dilute alkaline solution is obtained by diluting at least one of sodium hydroxide, potassium hydroxide, or ammonia water with distilled water, and the pH value of the dilute alkaline solution is 10-12.

7. The preparation method according to claim 6, characterized in that, The reaction temperature in step S2 is 50-90℃, the reaction time is 4-6h, and the reaction is continuously stirred during the process.

8. The preparation method according to claim 7, characterized in that, In steps S3 and S4, the spraying equipment is an electric nano-atomizing spray gun, the spraying distance is 10-30 cm, and the spraying amount is 30-50 grams of liquid per square meter.

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