A superhydrophobic, highly durable, highly transparent and dust-proof coating, its preparation method and applications

Abstract

The present invention provides a highly durable superhydrophobic and highly light-transmissive dust-proof coating, a preparation method thereof, and an application. The present invention adopts a double-layer design concept, first applying a bottom coating and then a surface coating. After the bottom coating is cured, a rough surface is formed, which can protect the surface layer of nanoparticles and increase the adhesion of the coating; the surface coating is composed of nano-silica, wax powder and a solvent. The nano-silica plays a role in superhydrophobicity. After the wax powder melts at high temperature, due to the capillary force, it will fill the larger voids in the nano-silica, so that the voids between the nanoparticles are smaller than the wavelength of light, achieving the purpose of increasing the light transmittance. Based on the high durability, high light transmittance and dust-proof performance of the superhydrophobic coating in the present invention, it is particularly suitable for outdoor scenarios such as photovoltaic modules, photovoltaic glass, building facades, 5G base stations, etc.

Description

Technical Field

[0001] The present invention relates to the field of hydrophobic materials, and more particularly, to a highly durable superhydrophobic and highly light-transmissive dust-proof coating, a preparation method thereof, and an application thereof. Background Art

[0002] Silicone is a polymer elastic material with both inorganic and organic properties. Its molecular main chain is composed of alternating silicon atoms and oxygen atoms (—Si—O—Si—), and the side chains are hydrocarbon or substituted hydrocarbon organic groups connected to silicon atoms. The molecular structure endows silicone with the following characteristics: ① The bond energy of the silicone main chain is higher than that of ultraviolet rays, having thermal stability, chemical stability, radiation resistance and heat resistance, and the expected service life is 30 years; ② Silicone has high elasticity, and the better the elasticity, the better the impact resistance of the coating; ③ Silicone has hydrophobic migration properties. Hydrophobic silicone molecules can migrate onto dust and other particles on the surface of the silicone, making the dust change from hydrophilic particles to hydrophobic particles.

[0003] Desert areas have advantages such as low space cost, long sunshine hours, few clouds, and strong sunlight, and are one of the ideal places for photovoltaic power generation. However, in desert areas, frequent strong winds will blow yellow sand onto the photovoltaic panels, preventing the photovoltaic panels from directly contacting sunlight and reducing the power generation efficiency. At present, the main means of cleaning the surface of photovoltaic modules is water cleaning. The cleaning methods include manual cleaning, semi-automatic cleaning and automatic cleaning methods, which require a large amount of manpower and material resources, and are also a challenge for water-scarce and arid areas with little annual precipitation. Therefore, a multifunctional coating with the functions of dust-proof, highly light-transmissive, highly durable and superhydrophobic is one of the effective solutions to photovoltaic dust accumulation. This solution can effectively reduce the cleaning cycle and save manpower and material resources.

[0004] However, most of the currently prepared coatings adopt a single-layer design concept. The directly coated nano-layer is only a few hundred nanometers thick, and the adhesion is poor, and it is very easy to fall off and cause failure. Some literatures in the prior art adopt a double-layer design concept, which increases the adhesion, but the bottom layer material has poor aging resistance, elasticity and hydrophobicity, resulting in poor durability of the superhydrophobic material. At the same time, the above coatings all have the disadvantages of low light transmittance and poor dust-proof performance. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention adopts a double-layer design concept, first applying a bottom coating and then applying a surface coating. After the bottom coating is cured, a rough surface is formed, which can protect the surface layer nano and increase the adhesion of the coating; the surface coating is composed of nano-silica, wax powder and solvent. The nano-silica plays a role in superhydrophobicity. After the wax powder melts at high temperature, due to the capillary force, it will fill the larger voids in the nano-silica, so that the voids between the nanos are smaller than the wavelength of light, achieving the purpose of increasing the light transmittance. The technical solution of the present invention:

[0006] The first aspect of the present invention is to provide a method for preparing a highly durable superhydrophobic and highly transparent dustproof coating, which specifically includes the following steps:

[0007] (1) Preparation of the bottom layer coating: Mix silica gel, a curing agent, and solvent A in a certain proportion to obtain a superhydrophobic bottom layer coating. Apply it on the glass surface and let it stand for 0.1 - 30 minutes (preferably 5 - 10 minutes). After the coating levels off, spray water vapor on the coating surface with a steam generator for 1 - 1000 seconds (preferably 20 - 600 seconds). At this time, phase separation occurs on the surface of the silica gel coating. After the water vapor on the coating surface volatilizes, a superhydrophobic bottom layer with a micron-scale rough structure is obtained.

[0008] (2) Preparation and coating of the surface layer coating: Put nano-silica, wax powder, and an adhesive into solvent B, and disperse them evenly by mechanical stirring or ultrasonic treatment to obtain a superhydrophobic surface layer coating. Spray the superhydrophobic surface layer coating on the above-mentioned superhydrophobic bottom layer with a spray gun. After drying, place it in an oven at 100 - 200 °C (preferably 150 - 200 °C) and bake for 30 - 600 seconds to obtain a highly durable superhydrophobic and highly transparent dustproof coating.

[0009] Further, in the step (1), the silica gel includes but is not limited to high-temperature vulcanized silica gel (HTV) and room-temperature vulcanized silica gel (RTV);

[0010] Further, in the step (1), the curing agent includes but is not limited to acidic curing agents, peroxide curing agents, alkylating curing agents, platinum-based curing agents, sulfur-cured silica gel curing agents, heat-cured silica gel curing agents, and photo-cured silica gel curing agents;

[0011] Further, in the step (1), the solvent A includes but is not limited to good solvents for silica gel such as toluene, xylene, ethyl acetate, tetrahydrofuran, acetone, etc.;

[0012] Further, in the step (1), the mass ratio of silica gel to solvent A is 1:0 - 10; preferably, the mass ratio of silica gel to solvent A is 1:0.5 - 5; more preferably, the mass ratio of silica gel to solvent A is 1:1;

[0013] Further, in the step (1), the silica gel is room-temperature vulcanized silica gel, and the mass ratio of room-temperature vulcanized silica gel to the curing agent is 100:1 - 50; preferably, the mass ratio of room-temperature vulcanized silica gel to the curing agent is 100:1 - 20; more preferably, the mass ratio of room-temperature vulcanized silica gel to the curing agent is 100:4;

[0014] Further, in the step (1), the silica gel is high-temperature vulcanized silica gel, and the mass ratio of the high-temperature vulcanized silica gel to the curing agent is 10:0.1 - 5; preferably, the mass ratio of the high-temperature vulcanized silica gel to the curing agent is 10:0.5 - 3; more preferably, the mass ratio of the high-temperature vulcanized silica gel to the curing agent is 10:1.5;

[0015] Further, in the step (1), the silica gel, the curing agent, and the solvent A are mixed in proportion and then mechanically stirred to obtain a superhydrophobic bottom layer coating;

[0016] Preferably, in the step (1), the mechanical stirring time is 10 - 30 minutes;

[0017] Further, in the step (1), the application amount of the superhydrophobic bottom layer coating is 50 - 2000 mL / m²; preferably, the application amount of the superhydrophobic bottom layer coating is 800 - 2000 mL / m²;

[0018] Further, in the step (1), the thickness of the superhydrophobic bottom layer is 0.1 - 50 µm; preferably, the thickness of the superhydrophobic bottom layer is 2 - 8 µm.

[0019] Further, in the step (1), the coating application methods include but are not limited to dip coating, brush coating, scraping coating, and spraying.

[0020] Further, in the step (2), the particle size of the nano-silica is 3 - 100 nm; preferably, the particle size of the nano-silica is 7 - 100 nm;

[0021] Further, in the step (2), the morphology of the nano-silica includes but is not limited to nanorods, nanospheres, amorphous, flocculent, or reticular, etc.;

[0022] Further, in the step (2), the wax powder includes but is not limited to high-temperature meltable wax powders such as polyethylene wax powder, polypropylene wax powder, polytetrafluoroethylene wax powder, polyvinylidene fluoride wax powder, polyamide wax powder, and palm wax powder;

[0023] Further, in the step (2), the solvent B includes but is not limited to ethanol, propanol, methyl acetate, ethyl acetate, acetone, dimethylformamide, cyclohexane, etc.;

[0024] Further, in the step (2), the adhesives include but are not limited to silica gel, acrylic adhesives, and polyurethane adhesives;

[0025] Further, in the step (2), the mass ratio of the nano-silica: wax powder: solvent B: adhesive is 1: 0.1-3: 20-200: 0.1-1; preferably, the mass ratio of the nano-silica: wax powder: solvent B: adhesive is 1: 0.5-3: 50-200: 0.2-1; more preferably, the mass ratio of the nano-silica: wax powder: solvent B: adhesive is 1: 1: 100: 0.2;

[0026] Further, in the step (2), the time for mechanical stirring or ultrasonic treatment for dispersion is 5-30 minutes; preferably, the time for mechanical stirring or ultrasonic treatment for dispersion is 10 minutes;

[0027] Further, in the step (2), the application amount of the superhydrophobic surface coating is 100-3000 ml / m²; preferably, the application amount of the superhydrophobic surface coating is 200-3000 ml / m²;

[0028] Further, in the step (2), the thickness of the superhydrophobic surface layer coated on the rough silica gel bottom layer is 10-500 nm; preferably, the thickness of the superhydrophobic surface layer coated on the rough silica gel bottom layer is 50-300 nm.

[0029] The second aspect of the present invention is to provide a highly durable superhydrophobic and highly transparent dust-proof coating prepared by the preparation method described in the first aspect of the present invention.

[0030] The third aspect of the present invention is to provide the application of the highly durable superhydrophobic and highly transparent dust-proof coating described in the second aspect of the present invention in the manufacturing of photovoltaic modules, photovoltaic glass, building facades, and 5G base stations.

[0031] The beneficial effects of the present invention:

[0032] The bottom layer and the surface layer of the present invention jointly form a highly durable superhydrophobic and highly transparent dust-proof coating. The rough micron structure of the bottom layer and the nano structure of the surface layer jointly endow the coating with high firmness and high transparency. The bottom layer uses silica gel as the main raw material, and a rough silica gel surface is prepared by the vapor phase separation method. This surface has the following advantages: ① The elasticity of silica gel can buffer external loads and improve the friction resistance of the superhydrophobic coating; ② The high anti-aging performance of silica gel can give the superhydrophobic coating a very long outdoor service life; ③ The hydrophobic migration of silica gel can restore the superhydrophobic performance of the aged nanoparticles on the surface layer; ④ The rough silica gel surface prepared by the vapor phase separation method can well accommodate the surface layer nanoparticles, improving the firmness of the superhydrophobic coating. In addition, the dense nano structure formed by the surface layer coating of the present invention fills the micron voids of the bottom layer, improving both the light transmittance of the coating and the hydrophobicity and dust-proof performance of the coating. The surface layer uses nano-silica as the main hydrophobic principle, and the light transmittance is increased by adding wax powder. This surface layer has the following advantages: ① Nano-silica is relatively easy to obtain, reducing the cost of the product; ② After the wax powder melts, it fills the large voids between the wax powders, increasing the light transmittance and solving the problem of poor light transmittance commonly found in superhydrophobic coatings; ③ After the wax powder melts, the connection between the nanos is made tighter, increasing the firmness of the coating. Description of the Drawings

[0033] Figure 1 It is a scanning electron microscope (SEM) image of the silica gel superhydrophobic bottom layer prepared in Example 1 of the present invention.

[0034] Figure 2 It is a scanning electron microscope (SEM) image of the highly durable superhydrophobic and highly transparent dust-proof coating prepared in Example 1 of the present invention. Detailed Description of the Invention

[0035] The present invention provides a highly durable superhydrophobic and highly transparent dust-proof coating, its preparation method and application. The coating prepared by the present invention reduces the light reflectivity of the photovoltaic glass plate, improves the power generation efficiency; is not prone to dust accumulation, shortening the cleaning cycle of the photovoltaic module; at the same time, it is easy to clean after dust accumulation, reducing the cleaning cost; in addition, the present invention uses the vapor phase separation method and uses silica gel as the raw material to prepare a rough silica gel bottom layer, which well protects the surface layer nanoparticles and improves the durability. The following is a specific description of the present invention in combination with examples to facilitate the further understanding of the present invention by those skilled in the art. However, the following described examples are only a part of the examples of the present invention and should not be regarded as any form of limitation of the present invention. It should be noted that the adjustments and improvements made by those of ordinary skill in the art based on the concept of the present invention should be regarded as within the protection scope of the present invention. For the specific technical operation steps and operators not specified in the examples, they are all carried out according to the general technical conditions described in the literature in this field or the relevant product specifications.

[0036] Example 1:

[0037] Add 10 g of room temperature vulcanizing silicone rubber and 0.4 g of curing agent (a mixture of silane, silanol and acetic acid) to 10 g of tetrahydrofuran, and stir with a blender for 20 minutes to obtain a superhydrophobic bottom coating. Spray the coating onto a glass plate with a spray gun, and the spraying amount is 2000 ml / m². After standing for 10 minutes, spray with a steam generator at a distance of 10 cm from the coating for 30 seconds to cause phase separation on the silicone rubber surface. Place the coating after phase separation at room temperature for 1 hour until the coating is dry to obtain a superhydrophobic bottom layer with a micron-scale rough structure.

[0038] Add 1 g of nano-silica (AEROSIL R202) (particle size about 14 nm), 1 g of polyethylene wax powder, and 0.2 g of acrylic resin to 100 g of ethanol, and ultrasonically disperse for 10 minutes to obtain the surface layer. Spray it onto the bottom layer with a spray gun, and the spraying amount is 1000 ml / m². Place the sample in an oven at 80 °C and dry for 20 minutes. After the solvent evaporates, bake it in an oven at 150 °C for 60 seconds to obtain a highly durable superhydrophobic and highly transparent dust-proof coating.

[0039] Performance test:

[0040] 1. Thickness of the bottom layer and the surface layer: Observe the thickness of the bottom layer and the surface layer using an electron microscope.

[0041] 2. Hydrophobicity test: The measurement of the contact angle and the rolling angle is carried out according to the method in GB / T 42694-2023. The difference is that both the contact angle and the rolling angle in this experiment are measured with 10 μl of water;

[0042] 3. Transmittance test: Use a Shimadzu UV-3600i Plus ultraviolet spectrophotometer in Japan, with a test wavelength range of 200 - 800 nm, and test its transmittance and reflectance.

[0043] 4. Dust-proof test: Place an ordinary glass plate and a glass plate coated with a multifunctional coating outdoors at the same time. After 30 days, calculate the dust accumulation mass per square meter by weighing, with the unit of g / m². The dust accumulation amount on the blank glass sheet is 5 g / m².

[0044] 5. Dust removal test (water): Spray 10 g / m² of dust on both an ordinary glass plate and a glass plate coated with a multifunctional coating at the same time, and test the water consumption for cleaning it up, with the unit of L / m². The water consumption of the blank glass sheet is 1 L / m²;

[0045] 6. Dust removal test (wind): Spray 10 g / m² of dust on a 20 cm square ordinary glass plate and a glass plate coated with a multifunctional coating respectively. At a distance of 15 cm from the surface, use a wind gun with a speed of 20 m / s to blow for 15 seconds respectively, and test the remaining dust amount. The remaining dust amount on the blank glass sheet is 7 g / m².

[0046] 7. Power generation efficiency test: Place the blank photovoltaic panel (SYP-M1810) and the photovoltaic panel coated with the multifunctional coating (SYP-M1810) outdoors at the same time, with the placement angle of both being 45°. Measure the power generation of the two panels at 10 am on the first day and the thirtieth day of placement using Fuyang HY005.

[0047] 8. Influence of placement angle on power generation efficiency: The sample preparation and data collection are the same as in Test 5, except that the placement angle is 20°;

[0048] 9. Friction resistance test: Using the method of sandpaper polishing, press the glass sheet coated with the superhydrophobic coating on the sandpaper with a weight, and push the glass sheet to make the coating and the sandpaper rub against each other. Use 1000-mesh sandpaper, a pressure of 330 KPa, and a friction distance of 10 cm as one cycle. After each cycle, measure the rolling angle and the contact angle, and stop the experiment when the rolling angle is greater than 10° or the contact angle is less than 150°.

[0049] 10. Water impact resistance test: The water impact resistance experiment uses a self-built device that can provide a 1-mm diameter water column with a water pressure of 2000 Pa. The water column impacts the superhydrophobic surface, and the angle between the water column and the superhydrophobic surface is 45°. Stop the experiment when water droplets adhere to the surface, and record the water impact resistance time;

[0050] The test results are as follows:

[0051] Bottom layer thickness: 4 μm

[0052] Surface layer thickness: 120 nm

[0053] Contact angle (measured with 10 μL of water): 165°;

[0054] Rolling angle (measured with 10 μL of water): 5°;

[0055] Light transmittance: 95%;

[0056] Reflectance: 2%

[0057] Dust accumulation: 0.5 g / m²;

[0058] Dust removal test (water): 0.05 L / m²;

[0059] Dust removal test (wind): 0.1 g / m²;

[0060] Power generation efficiency (first day): 2 W for the blank photovoltaic panel and 2.1 W for the coated photovoltaic panel, with a difference of 5%;

[0061] Power generation efficiency (thirtieth day): 1.8 W for the blank photovoltaic panel and 2.2 W for the coated photovoltaic panel, with a difference of 22.2%;

[0062] Power generation efficiency at 20°: 1.6 W for the blank PV panel and 1.9 W for the coated PV panel, with a difference of 18.8%;

[0063] Abrasion resistance: 100 cycles;

[0064] Water impact resistance time: 200 minutes.

[0065] Example 2:

[0066] Add 10 g of high-temperature vulcanized silica gel and 1.5 g of curing agent (a mixture of silicone and platinum catalyst) to 10 g of tetrahydrofuran, stir with a blender for 20 minutes to obtain a superhydrophobic bottom coating. Use a glass rod to scrape the coating onto a glass plate, with a scraping amount of 1000 ml / m². After standing for 10 minutes, spray with a steam generator at a distance of 10 cm from the coating for 600 seconds to cause phase separation on the silica gel surface. Cure the coating obtained after phase separation at 80°C for 1 hour to obtain a superhydrophobic bottom layer with a micron-scale rough structure.

[0067] Add 1 g of nano-silica (AEROSIL R812) (particle size about 7 nm), 0.5 g of polypropylene wax powder, and 1 g of silica gel to 100 g of ethyl acetate, ultrasonically disperse for 10 minutes to obtain a surface coating. Spray it onto the bottom coating with a spray gun, with a spraying amount of 2000 ml / m². Place the sample in an 80°C oven and dry for 20 minutes. After the solvent evaporates, place it in a 160°C oven and bake for 400 seconds to obtain a highly durable superhydrophobic and highly light-transmissive dust-proof coating.

[0068] The test results are as follows:

[0069] Bottom layer thickness: 2 μm

[0070] Surface layer thickness: 190 nm

[0071] Contact angle (tested with 10 μl of water): 160°;

[0072] Rolling angle (tested with 10 μl of water): 6°;

[0073] Light transmittance: 92%;

[0074] Reflectivity: 2.5%

[0075] Dust accumulation amount: 1 g / m²;

[0076] Dust removal test (water): 0.07 l / m²;

[0077] Dust removal test (wind): 0.15 g / m²;

[0078] Power generation efficiency (on the first day): 2 W for the blank PV panel and 2.1 W for the coated PV panel, with a difference of 5%;

[0079] Power generation efficiency (on the 30th day): 1.8 W for the blank PV panel and 2.1 W for the coated PV panel, with a difference of 16.7%;

[0080] Power generation efficiency at a 20° angle: 1.6 W for the blank PV panel and 1.85 W for the coated PV panel, with a difference of 15.6%;

[0081] Water impact resistance time: 210 minutes.

[0082] Example 3:

[0083] Add 10 g of room temperature vulcanizing silicone rubber and 0.4 g of curing agent (a mixture of silane, silanol, and acetic acid) to 10 g of ethyl acetate, and stir with a blender for 20 minutes to obtain a superhydrophobic bottom coating. Use a glass rod to scrape the coating onto a glass plate, with a scraping amount of 800 ml / m². After standing for 10 minutes, spray with a steam generator at a distance of 5 cm from the coating for 20 seconds to cause phase separation on the silicone surface. Let the coated layer stand at room temperature for 1 hour until dry to obtain a superhydrophobic bottom layer with a microscale rough structure.

[0084] Add 1 g of nanosilica rods (particle size about 50 nm), 2 g of polyvinylidene fluoride wax powder, and 0.2 g of polyurethane adhesive to 50 g of ethyl acetate, and ultrasonically disperse for 10 minutes to obtain a surface coating. Spray it onto the bottom coating with a spray gun, with a spraying amount of 200 ml / m². Place the sample in an 80°C oven and dry for 20 minutes. After the solvent has evaporated, place it in a 200°C oven and bake for 600 seconds to obtain a highly durable superhydrophobic and highly transparent dust-proof coating.

[0085] The test results are as follows:

[0086] Bottom layer thickness: 2 µm

[0087] Surface layer thickness: 50 nm

[0088] Contact angle (tested with 10 µl of water): 161°;

[0089] Rolling angle (tested with 10 µl of water): 7°;

[0090] Light transmittance: 90%;

[0091] Reflectance: 2.7%

[0092] Dust accumulation amount: 0.7 g / m²;

[0093] Dust removal test (water): 0.07 l / m²;

[0094] Dust removal test (wind): 0.15 g / m²;

[0095] Power generation efficiency (first day): 2 W for the blank PV panel and 2.2 W for the coated PV panel, with a 10% difference.

[0096] Power generation efficiency (thirtieth day): 1.7 W for the blank PV panel and 2 W for the coated PV panel, with a 17.6% difference.

[0097] Power generation efficiency at a 20° angle: 1.6 W for the blank PV panel and 1.8 W for the coated PV panel, with a 12.5% difference.

[0098] Abrasion resistance: 70 cycles.

[0099] Water impact resistance time: 150 minutes.

[0100] Example 4:

[0101] Add 10 grams of room temperature vulcanized silicone rubber and 0.4 grams of curing agent (a mixture of silane, silanol, and acetic acid) to 10 grams of xylene, and stir with a blender for 20 minutes to obtain a superhydrophobic bottom coating. Use a glass rod to scrape the coating onto a glass plate, with a scraping amount of 2000 milliliters per square meter. After standing for 10 minutes, spray with a steam generator at a distance of 15 cm from the coating for 40 seconds to cause phase separation on the silicone surface. Let the coating obtained after phase separation stand at room temperature for 1 hour until dry to obtain a superhydrophobic bottom layer with a micron-scale rough structure.

[0102] Add 1 gram of nano-silica spheres (particle size about 100 nm), 3 grams of palm wax powder, and 0.2 grams of polyurethane adhesive to 200 grams of ethyl acetate, and ultrasonically disperse for 10 minutes to obtain a surface coating. Spray it onto the bottom coating with a spray gun, with a spraying amount of 3000 milliliters per square meter. Place the sample in an 80°C oven and dry for 20 minutes. After the solvent has evaporated, place it in a 150°C oven and bake for 120 seconds to obtain a highly durable superhydrophobic and highly transparent dust-proof coating.

[0103] The test results are as follows:

[0104] The thickness of the bottom layer is: 4 microns;

[0105] The thickness of the surface layer is: 300 nm;

[0106] Contact angle (tested with 10 μL of water): 158°;

[0107] Rolling angle (tested with 10 μL of water): 8°;

[0108] Light transmittance: 89%;

[0109] Reflectivity: 3%;

[0110] Dust accumulation amount: 1.2 g / m²;

[0111] Dust removal test (water): 0.08 L / m²;

[0112] Dust removal test (wind): 0.17 g / m²;

[0113] Power generation efficiency (first day): 2 W for the blank PV panel and 2.15 W for the coated PV panel, with a difference of 7.5%;

[0114] Power generation efficiency (thirtieth day): 1.75 W for the blank PV panel and 2.1 W for the coated PV panel, with a difference of 20%;

[0115] Power generation efficiency at a 20° placement: 1.6 W for the blank PV panel and 1.8 W for the coated PV panel, with a difference of 12.5%;

[0116] Abrasion resistance: 120 cycles.

[0117] Water impact resistance time: 260 minutes.

[0118] Example 5:

[0119] Mix 10 g of room temperature vulcanizing silicone rubber and 0.4 g of curing agent (a mixture of silane, silanol, and acetic acid), stir with a blender for 20 minutes to obtain a superhydrophobic bottom coating. Use a glass rod to scrape the coating onto a glass plate, with a scraping amount of 2000 ml / m². After standing for 10 minutes, spray with a steam generator at a distance of 15 cm from the coating for 40 seconds to cause phase separation on the silicone surface. Let the coated layer stand at room temperature for 1 hour until dry to obtain a superhydrophobic bottom layer with a micron-scale rough structure.

[0120] Add 1 g of nano-silica spheres (particle size of about 100 nm), 3 g of palm wax powder, and 0.2 g of polyurethane adhesive to 200 g of ethyl acetate, ultrasonically disperse for 10 minutes to obtain a surface coating. Spray it onto the bottom coating with a spray gun, with a spraying amount of 3000 ml / m². Place the sample in an 80°C oven and dry for 20 minutes. After the solvent has evaporated, place it in a 150°C oven and bake for 120 seconds to obtain a highly durable superhydrophobic and highly transparent dust-proof coating.

[0121] The test results are as follows:

[0122] Bottom layer thickness: 8 µm;

[0123] Surface layer thickness: 300 nm;

[0124] Contact angle (tested with 10 µl of water): 157°;

[0125] Rolling angle (tested with 10 µl of water): 6°;

[0126] Light transmittance: 88%;

[0127] Reflectivity: 3%;

[0128] Dust accumulation: 1.3 g / m²;

[0129] Dust removal test (water): 0.07 L / m²;

[0130] Dust removal test (wind): 0.18 g / m²;

[0131] Power generation efficiency (first day): 2 W for the blank PV panel and 2.14 W for the coated PV panel, with a difference of 7%;

[0132] Power generation efficiency (thirtieth day): 1.75 W for the blank PV panel and 2.1 W for the coated PV panel, with a difference of 20%;

[0133] Power generation efficiency at a 20° inclination: 1.6 W for the blank PV panel and 1.8 W for the coated PV panel, with a difference of 12.5%;

[0134] Abrasion resistance: 130 cycles.

[0135] Water impact resistance time: 280 minutes.

[0136] Comparative example 1:

[0137] 10 g of room temperature vulcanizing silicone rubber and 0.4 g of curing agent (a mixture of silane, silanol, and acetic acid) were added to 10 g of tetrahydrofuran, and the mixture was stirred for 20 minutes with a blender to obtain a superhydrophobic bottom coating. The coating was sprayed onto a glass plate using a spray gun at a spraying rate of 2000 mL / m². The coating was left at room temperature for 1 hour until it cured to obtain a smooth silicone rubber bottom layer.

[0138] 1 g of nano-silica (AEROSIL R202) (particle size of about 14 nm), 1 g of polyethylene wax powder, and 0.2 g of acrylic resin were added to 100 g of ethanol, and the mixture was ultrasonically dispersed for 10 minutes to obtain a surface layer. The surface layer was sprayed onto the bottom layer using a spray gun at a spraying rate of 1000 mL / m². The sample was placed in an 80°C oven and dried for 20 minutes. After the solvent had evaporated, the sample was placed in a 150°C oven and baked for 60 seconds to obtain a coating.

[0139] The test results are as follows:

[0140] Surface layer thickness: 130 nm

[0141] Contact angle (tested with 10 μL of water): 160°;

[0142] Rolling angle (tested with 10 μL of water): 6°;

[0143] Transmittance: 97%;

[0144] Reflectance: 2%

[0145] Abrasion resistance: 2 cycles.

[0146] Water impact resistance time: 5 minutes.

[0147] Comparative Example 2:

[0148] 10 g of room temperature vulcanizing silica gel and 0.4 g of curing agent (a mixture of silane, silanol and acetic acid) were added to 10 g of tetrahydrofuran, and stirred with a blender for 20 minutes to obtain a superhydrophobic bottom coating. The coating was sprayed onto a glass plate with a spray gun, and the spraying amount was 2000 ml / m². After standing for 10 minutes, water vapor was sprayed from a water vapor generator 10 cm away from the coating for 30 seconds to cause phase separation on the silica gel surface. The coating after phase separation was placed at room temperature for 1 hour until dry to obtain a superhydrophobic bottom layer with a micron-scale rough structure.

[0149] 1 g of nano-silica (AEROSIL R202) (particle size about 14 nm) and 0.2 g of acrylic resin were added to 100 g of ethanol, and ultrasonically dispersed for 10 minutes to obtain the surface layer. It was sprayed onto the bottom layer with a spray gun, and the spraying amount was 1000 ml / m². The sample was placed in an oven at 80 °C and dried for 20 minutes. After the solvent evaporated, it was placed in an oven at 150 °C and baked for 60 seconds to obtain the coating.

[0150] Performance test:

[0151] Bottom layer thickness: 4 µm

[0152] Surface layer thickness: 100 nm

[0153] Contact angle (tested with 10 µl of water): 166°;

[0154] Rolling angle (tested with 10 µl of water): 3°;

[0155] Light transmittance: 60%;

[0156] Reflectivity: 2%

[0157] Dust accumulation amount: 0.4 g / m²;

[0158] Abrasion resistance: 80 cycles.

[0159] Water impact resistance time: 180 minutes.

[0160] Conclusion:

[0161] Comparing Example 1 and Comparative Example 1, it was found that when the bottom layer has no rough micron-scale structure, the surface layer cannot be effectively protected, resulting in a significant reduction in its abrasion resistance. Therefore, the rough structure of the bottom layer is the key to improving the durability of superhydrophobic materials.

[0162] Comparing Example 1 and Comparative Example 2, it is found that: ① Without the addition of wax powder, the light transmittance of the coating is greatly reduced, indicating that the light transmittance can be improved after the wax powder melts; ② Without the addition of wax powder, the friction resistance and water flushing resistance are slightly reduced, indicating that the wax powder can also improve the firmness of the coating.

[0163] The above are only the preferred embodiments of the present invention and do not impose any limitations on the present invention. For those skilled in the art of this technology, any modifications and changes made to the above embodiments according to the technical essence of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a highly durable super-hydrophobic and highly transparent dustproof coating, characterized in that: The specific steps include: (1) Preparation of a base coating: Silica gel, a curing agent, and a solvent A are mixed in proportion to obtain a super-hydrophobic base coating, which is applied to a glass surface and allowed to stand for 0.1-30 minutes. After the coating is leveled, water vapor is sprayed onto the coating surface using a steam generator for 1-1000 seconds. Phase separation occurs on the surface of the silica gel coating. After the water vapor on the coating surface evaporates, a super-hydrophobic base coating having a micron-scale rough structure is obtained. The solvent A includes toluene, xylene, ethyl acetate or tetrahydrofuran; (2) placing nano-silica, wax powder and adhesive into solvent B, uniformly dispersing them by mechanical stirring or ultrasonic treatment to obtain a super-hydrophobic surface coating, applying the super-hydrophobic surface coating on the super-hydrophobic bottom layer with a spray gun, and after drying, placing the coating in an oven at 100-200° C. for 30-600 seconds to obtain a highly durable super-hydrophobic and highly transparent dustproof coating; The solvent B includes ethanol, propanol, methyl acetate, ethyl acetate, acetone, dimethylformamide or cyclohexane.

2. The preparation method according to claim 1, characterized in that: In the step (1), the silica gel includes high temperature vulcanized silica gel or room temperature vulcanized silica gel.

3. The preparation method according to claim 1, characterized in that: In the step (1), the mass ratio of silica gel to solvent A is 1:0-10.

4. The preparation method according to claim 1, characterized in that: In the step (1), the silicone is room temperature vulcanized silicone, and the mass ratio of the room temperature vulcanized silicone: curing agent is 100:1-50.

5. The preparation method according to claim 1, characterized in that: In the step (1), the silica gel is high temperature vulcanized silica gel, and the mass ratio of the high temperature vulcanized silica gel to the curing agent is 10:0.1-5; the application amount of the super hydrophobic primer is 50-2000 ml / m2; and the thickness of the super hydrophobic primer is 0.1-50 μm.

6. The preparation method according to claim 1, characterized in that: In the step (2), the nano-silicon dioxide has a particle size of 3-100 nanometers; the nano-silicon dioxide has a morphology including nanorods, nanospheres, amorphous, flocculent or mesh; the wax powder includes polyethylene wax powder, polypropylene wax powder, polytetrafluoroethylene wax powder, polyvinylidene fluoride wax powder, polyamide wax powder or palm wax powder; the adhesive includes silicone, acrylic adhesive or polyurethane adhesive.

7. The preparation method according to claim 1, characterized in that: In the step (2), the mass ratio of the nano-silicon dioxide: wax powder: solvent B: adhesive is 1:0.1-3:20-200:0.1-1.

8. The preparation method according to claim 1, characterized in that: In the step (2), the application amount of the super hydrophobic surface coating is 100-3000 ml / m2; the thickness of the super hydrophobic surface layer coated on the rough silica gel base layer is 10-500 nanometers.

9. A highly durable, super-hydrophobic, highly light-transmitting dust-proof coating prepared by the preparation method according to any one of claims 1 to 8.

10. Application of the highly durable super-hydrophobic and highly transparent dust-proof coating described in claim 9 in the manufacture of photovoltaic modules, photovoltaic glass, building exterior walls, and 5G base stations.

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