Anti-scratch coating liquid for photovoltaic module and preparation method of anti-scratch coating liquid

Abstract

The invention discloses an anti-scratch coating liquid for a photovoltaic module and a preparation method of the anti-scratch coating liquid, and relates to the technical field of coating liquids. The invention discloses an anti-scratch coating liquid for a photovoltaic module. The coating is prepared from the following raw materials in parts by weight: 18 to 25 parts of methyl isobutyl ketone, 8 to 12 parts of isopropanol, 3 to 6 parts of propylene glycol methyl ether acetate, 2 to 4 parts of dipropylene glycol methyl ether, 15 to 22 parts of modified epoxy resin, 3 to 5 parts of silane coupling agent KH-550, 25 to 35 parts of modified nano silicon dioxide sol, 1 to 2.5 parts of nano zirconium oxide, 2 to 4 parts of nano aluminum nitride powder and 0.8 to 1.5 parts of polyoxyethylene fatty ether phosphate. The coating is prepared from the following components in parts by weight: 0.5 to 1.2 parts of an ultraviolet light absorber UV-327, 0.2 to 0.5 part of an antioxidant 1010, 1.5 to 3 parts of polydimethylsiloxane, 0.1 to 0.3 part of an organic silicon flatting agent and 0.3 to 0.6 part of dibutyltin dilaurate. According to the anti-scratch coating liquid for the photovoltaic module, raw materials with high hardness and stability are matched with a dispersing agent with high adaptability, so that the problem of aging of an organic base film layer is effectively avoided, substance dispersity is improved through fine preparation operation, and a finally formed film is high in scratch resistance and weather resistance and can adapt to a complex environment for a long time, and light transmittance and power generation stability of the module are guaranteed.

Description

Technical Field

[0001] This invention relates to the field of coating liquid technology, specifically to an anti-scratch coating liquid for photovoltaic modules and its preparation method. Background Technology

[0002] As a core component of solar power generation systems, photovoltaic modules are exposed to complex outdoor environments for extended periods. Their surface glass covers are susceptible to scratches and damage from factors such as wind and sand erosion, hail impacts, bird droppings corrosion, and human wiping. This damage significantly reduces the light transmittance of the cover, leading to a decrease in the module's photoelectric conversion efficiency. It also damages the surface protective layer, accelerating the aging and degradation of the internal solar cells, shortening the overall lifespan of the photovoltaic module, and increasing maintenance costs.

[0003] Currently, the industry primarily improves scratch resistance by coating photovoltaic glass surfaces with a coating solution. Existing coating solutions mainly use organic resins such as epoxy resin and acrylic resin as base materials, combined with inorganic particles such as nano-silica and titanium dioxide to enhance hardness. However, traditional formulations have significant technical drawbacks: while some anatase or unmodified rutile nano-titanium dioxide can provide a certain degree of self-cleaning, its photocatalytic activity accelerates the degradation of the organic base material under ultraviolet irradiation, leading to film powdering and yellowing; nanoparticles are prone to agglomeration, resulting in poor film uniformity and uneven scratch resistance; poor solvent evaporation rate matching easily leads to defects such as pinholes and orange peel during film formation, affecting light transmission and appearance; insufficient adhesion between the film and the glass substrate makes it prone to peeling after long-term outdoor use, failing to provide sustained protection.

[0004] Furthermore, existing coating solution preparation processes often lack precise control, such as insufficient raw material pretreatment and rudimentary control of feeding and reaction temperatures. This leads to low product performance stability, making it difficult to meet the stringent requirements of photovoltaic modules for weather resistance, scratch resistance, and light transmittance during long-term outdoor use. Therefore, developing a risk-free, highly stable, and outdoor-compatible anti-scratch coating solution for photovoltaic modules has become an urgent problem for the industry. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a scratch-resistant coating liquid for photovoltaic modules and its preparation method, which solves the problems of photocatalytic degradation of the film, nanoparticle aggregation defects, and insufficient weather resistance of the film.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A scratch-resistant coating liquid for photovoltaic modules comprises the following raw materials in parts by weight: 18-25 parts methyl isobutyl ketone, 8-12 parts isopropanol, 3-6 parts propylene glycol methyl ether acetate, 2-4 parts dipropylene glycol methyl ether, 15-22 parts modified epoxy resin, 3-5 parts silane coupling agent KH-550, 25-35 parts modified nano silica sol, 1-2.5 parts nano zirconium oxide, 2-4 parts nano aluminum nitride powder, 0.8-1.5 parts polyoxyethylene fatty ether phosphate, 0.5-1.2 parts ultraviolet absorber UV-327, 0.2-0.5 parts antioxidant 1010, 1.5-3 parts polydimethylsiloxane, 0.1-0.3 parts organosilicon leveling agent, and 0.3-0.6 parts dibutyltin dilaurate.

[0007] Furthermore, the nano-zirconia is surface-pretreated nano-zirconia. The pretreatment steps are as follows: untreated nano-zirconia powder is added to four times its mass of anhydrous ethanol, and ultrasonically dispersed at 250W for 30 minutes. Then, 2% by mass of silane coupling agent KH-570 of nano-zirconia is added, and the mixture is reacted at 60℃ and 400r / min for 2 hours. After the reaction, the mixture is centrifuged, the precipitate is collected, and vacuum dried at 90℃ for 3 hours to obtain the nano-zirconia. Anhydrous ethanol ultrasonic dispersion removes impurities from the surface of nano-zirconia and reduces the tendency to agglomerate; silane coupling agent KH-570 graft modification enhances its compatibility with organic resins; stirring at 60℃ and 400r / min ensures sufficient reaction; and vacuum drying at 90℃ avoids secondary contamination. Ultimately, the nano-zirconia is stably dispersed in the coating solution, and no significant agglomeration is observed after standing for 72 hours. After film formation, the film hardness and light transmittance are uniformly improved.

[0008] Furthermore, the nano-aluminum nitride powder is a coated and modified nano-aluminum nitride. The coating and modification steps are as follows: untreated nano-aluminum nitride powder is dispersed in 5 times its mass of deionized water to form a suspension. 6% by mass of trisodium citrate is added as a dispersant, and the mixture is ultrasonically treated at 350W for 40 minutes. Subsequently, the temperature is raised to 65°C, and 15% by mass of aluminum nitride and 10% sodium silicate solution are added dropwise. After the addition is complete, the pH is adjusted to 6 with dilute nitric acid, and the mixture is kept warm and stirred for 2.5 hours. After the reaction is completed, the mixture is centrifuged, the precipitate is washed 4 times with deionized water, and dried at 110°C for 5 hours to obtain the nano-aluminum nitride powder. Trisodium citrate and 350W ultrasound synergistically inhibit the agglomeration of nano-aluminum nitride; sodium silicate coating forms a silica protective layer, isolating it from adverse effects with the organic phase; 65℃ heat preservation and pH=6 control promote full coating reaction; 110℃ drying removes moisture, retaining more than 90% of the thermal conductivity of nano-aluminum nitride, improving its compatibility in the coating solution, and avoiding a decrease in film transmittance.

[0009] Furthermore, the modified epoxy resin is prepared using the following specific steps: A1. Take bisphenol A type epoxy resin and add methyl isobutyl ketone. Stir at 200-300 r / min and heat to 90-95℃. Then slowly add adipic acid and p-toluenesulfonic acid and heat to 110-120℃. Keep the temperature for 4-5 hours. Take a sample every 1 hour to detect the acid value. When the acid value drops to 10-15 mg KOH / g, stop the reaction. Then cool down to 60-70℃ and add isopropanol to dilute to obtain the first modified carboxylated epoxy resin. A2. Take the first modified carboxylated epoxy resin, heat it to 80-85℃, add silane coupling agent KH-550 and deionized water, stir at 400-500 r / min, then add antioxidant 1010 and dibutyltin dilaurate, continue to maintain the temperature and stirring rate, and keep the reaction at this temperature for 3-4 hours; during this period, monitor the intensity change of the characteristic peak 1080 cm⁻¹ of siloxane by Fourier transform infrared spectroscopy until the peak intensity stabilizes, then stop the reaction, add propylene glycol methyl ether acetate to dilute, and cool to 50-55℃ to obtain the second modified siloxane crosslinked epoxy resin. A3. Take the second modified siloxane crosslinked epoxy resin, add untreated nano-zirconia and polydimethylsiloxane, and perform high-speed shear dispersion treatment at 8000-10000 r / min for 30-45 min. Then transfer it to a ball mill with 5 mm diameter agate balls and a ball-to-material ratio of 8:1. Ball mill for 2-3 h to ensure uniform dispersion of nano-zirconia. After ball milling, heat to 70-75℃, add UV absorber UV-327, stir for 1-1.5 h, then cool to room temperature and filter through a 1 μm filter membrane to obtain the modified epoxy resin.

[0010] Furthermore, in A1, the ratio of bisphenol A type epoxy resin, methyl isobutyl ketone, adipic acid, p-toluenesulfonic acid, and isopropanol is 300-350g: 150-180mL: 25-30g: 0.5-1g: 30-40mL. The epoxy resin is stirred to dissolve in methyl isobutyl ketone. The reaction is accelerated at 90-95℃ to promote ring-opening of the epoxy groups with adipic acid, and p-toluenesulfonic acid catalyzes and accelerates the reaction, introducing carboxyl groups into the resin chain. The mixture is kept at 110-120℃ for 4-5 hours, and the amount of carboxyl groups is controlled by adjusting the acid value to 10-15mgKOH / g. The mixture is then cooled and diluted with isopropanol to enhance the resin's reactivity, laying the foundation for subsequent crosslinking.

[0011] Furthermore, in A2, the ratio of the first modified carboxylated epoxy resin, silane coupling agent KH-550, deionized water, antioxidant 1010, dibutyltin dilaurate, and propylene glycol methyl ether acetate is 200-250g: 10-15g: 5-8mL: 0.8-1.2g: 1-1.5g: 20-25mL. The alkoxy groups of silane coupling agent KH-550 hydrolyze to generate silanol groups, which condense with the carboxyl groups of the resin to form Si-OC bonds. The silanol groups then self-condense to form a Si-O-Si crosslinking network. Dibutyltin dilaurate catalyzes the reaction, antioxidant 1010 prevents resin oxidation, and 3-4 hours of heat treatment ensures sufficient crosslinking, improving the resin's weather resistance and compatibility with inorganic particles, and reducing interfacial stress.

[0012] Furthermore, in A3, the ratio of the second modified siloxane crosslinked epoxy resin, nano-zirconia, polydimethylsiloxane, and UV absorber UV-327 is 180-220g: 8-12g: 2-3g: 1-2g. Shearing and ball milling are used in combination to uniformly disperse the nano-zirconia in the resin, improving hardness through the nano-reinforcing effect. Polydimethylsiloxane improves resin flowability, and 70-75℃ promotes the dissolution and dispersion of UV absorber UV-327 for UV protection. A 1μm filter membrane removes impurities, ensuring resin purity and overall performance.

[0013] Furthermore, the modified nano-silica sol is prepared using the following specific steps: B1. Take a nano-silica sol with a solid content of 30%, dilute it with isopropanol, stir at 300-400 r / min and heat to 50-60℃, then slowly add a mixture of silane coupling agent KH-560 and deionized water, controlling the addition time at 60-90 min; after the addition is complete, heat to 70-75℃ and keep the reaction at this temperature for 3-4 h, taking samples every 30 min to detect particle size changes until the particle size stabilizes at 15-20 nm; after the reaction is complete, cool to room temperature and remove 10-15% of the solvent by vacuum distillation to obtain the first modified nano-silica sol; B2. Take the first modified nano-silica sol, add the above modified epoxy resin, stir at 500-600 r / min and heat to 80-85℃, then add dibutyltin dilaurate, and add ethanolamine dropwise to adjust the pH to 7-8. Then keep the reaction at the temperature for 5-6 hours. During this period, monitor the intensity change of the characteristic peak of the epoxy group at 910 cm⁻¹ by Fourier transform infrared spectroscopy until the peak intensity decreases by 80%. After the reaction is completed, add propylene glycol methyl ether acetate to dilute, and cool to 40-45℃ to obtain the second modified nano-silica sol. B3. Take the second modified nano-silica sol and add untreated nano-aluminum nitride powder, then add polyoxyethylene fatty ether phosphate ester. Disperse the mixture using ultrasonic power 300W for 60-90 minutes, stopping the machine every 20 minutes and stirring for 10 minutes to prevent local overheating. After dispersion, cool to room temperature, add UV absorber UV-327, and stir continuously at 300-400r / min for 40-60 minutes until uniformly dispersed. Cool to room temperature and filter using a 1μm filter membrane to obtain the modified nano-silica sol.

[0014] Furthermore, in B1, the ratio of nano-silica sol, isopropanol, silane coupling agent KH-560, and deionized water is 400-500g: 200-250mL: 15-20g: 10-15mL. Isopropanol dilution reduces interparticle forces, and stirring at 300-400r / min and 50-60℃ creates suitable conditions for the reaction. The alkoxy groups of silane coupling agent KH-560 hydrolyze to generate silanol groups, which dehydrate and condense with the silanol groups on the surface of nano-silica to form Si-O-Si bonds, grafting silane coupling agent KH-560 onto the particle surface while retaining epoxy groups. Holding at 70-75℃ for 3-4h ensures complete reaction, ultimately improving compatibility with the resin by introducing organic functional groups, stabilizing the particle size at 15-20nm, and avoiding agglomeration.

[0015] Furthermore, in B2, the ratio of the first modified nano-silica sol, modified epoxy resin, dibutyltin dilaurate, and propylene glycol methyl ether acetate is 300-350g: 80-100g: 2-3g: 50-60mL. Stirring ensures thorough mixing of the sol and modified epoxy resin. Catalysis with dibutyltin dilaurate at 80-85℃ promotes the ring-opening reaction between the carboxyl and hydroxyl groups in the resin and the epoxy groups on the sol surface, forming ester and ether bonds. Ethanolamine is used to adjust the pH to 7-8 to optimize the reaction environment. Maintaining the temperature for 5-6 hours allows the epoxy group reaction rate to reach 80%, achieving chemical grafting and enhancing the subsequent film hardness and anti-delamination ability.

[0016] Furthermore, the ratio of the second modified nano-silica sol, nano-aluminum nitride powder, polyoxyethylene fatty ether phosphate, and ultraviolet absorber UV-327 in B3 is 250-300g: 15-20g: 3-5g: 2-3g. Polyoxyethylene fatty ether phosphate prevents aggregation through electrostatic and steric hindrance effects, while aluminum nitride weakly interacts with the residual hydroxyl groups in the sol to achieve bonding, imparting thermal conductivity to the sol. UV absorber UV-327 is added at room temperature and stirred to ensure uniform dispersion for UV absorption and anti-aging. Impurities are removed by filtration through a 1μm filter membrane, ensuring the sol's performance and purity.

[0017] A method for preparing an anti-scratch coating liquid for photovoltaic modules specifically includes the following steps: S1. Add methyl isobutyl ketone, isopropanol, propylene glycol methyl ether acetate and dipropylene glycol methyl ether to a three-necked flask. Stir at 200-300 r / min and mix at room temperature for 15-20 min to form a mixed solvent. Mixing at room temperature avoids abnormal solvent evaporation rate. The resulting mixed solvent can precisely adjust the viscosity and evaporation gradient of the subsequent system, laying the foundation for the dissolution of raw materials and the uniformity of film formation. S2. Slowly add the modified epoxy resin to the above mixed solvent, increase the stirring speed to 400-500 r / min and heat to 50-55℃, keep warm and stir for 30-40 min until the resin is completely dissolved; then add the silane coupling agent KH-550 and continue stirring for 20-30 min to form a premixed solution. S3. Add the modified nano-silica sol, nano-zirconia, and nano-aluminum nitride powder to the premixed solution in sequence, adjust the stirring speed to 600-700 r / min, and stir at room temperature for 1-1.5 h to prevent particle agglomeration caused by high temperature; then add polyoxyethylene fatty ether phosphate, and continue stirring for 30-45 min to further inhibit particle agglomeration, ensure that the nanoparticles are uniformly dispersed in the premixed solution, and ensure the stability of the film performance; S4. Add UV absorber UV-327, antioxidant 1010, polydimethylsiloxane, and silicone leveling agent to the system. Reduce the stirring speed to 300-400 r / min and raise the temperature to 60-65℃. Keep stirring at this temperature for 40-50 min to ensure uniform dispersion of the additives. UV absorber UV-327 and antioxidant 1010 give the system anti-aging ability, while polydimethylsiloxane and silicone leveling agent optimize the hydrophobicity and smoothness of the film surface. S5. Add dibutyltin dilaurate, maintain the stirring rate at 300-400 r / min, heat to 70-75℃, and keep the reaction at this temperature for 1-1.5 h. After the reaction is complete, take a sample to test the viscosity at 25℃. If the viscosity is within acceptable limits, cool the system to room temperature and filter under reduced pressure using a 1 μm organic filter membrane. After filtration, transfer the coating solution to a sealed container and let it stand and age at 25℃ in the dark for 24-36 h to obtain the anti-scratch coating solution for photovoltaic modules.

[0018] Furthermore, in step S5, if the viscosity is too high, an appropriate amount of methyl isobutyl ketone is added to adjust it; if the viscosity is too low, a small amount of solvent is removed by vacuum distillation. This avoids problems such as excessively high viscosity leading to difficulties in coating and excessively thick films, or excessively low viscosity leading to excessively thin films and poor uniformity, ensuring a stable coating process and that the film performance meets standards.

[0019] This invention provides an anti-scratch coating liquid for photovoltaic modules and its preparation method, which has the following beneficial effects: 1. This invention abandons traditional raw materials that easily cause photocatalytic problems, selecting modified nano-zirconia with no photocatalytic activity, and modifying nano-aluminum nitride with silica coating. Simultaneously, it pre-treats the nano-zirconia with a silane coupling agent and performs three grafting and composite modification on the nano-silica sol to construct a stable interfacial structure between inorganic particles and organic resin. This multi-component synergistic modification design completely cuts off the contact path between the photocatalytic components and the organic matrix, avoiding film powdering and yellowing caused by organic resin degradation under ultraviolet irradiation, ensuring the structural integrity of the film during long-term outdoor use, and extending the surface protection cycle of photovoltaic modules.

[0020] 2. This invention forms a systematic dispersion control scheme from raw material pretreatment to preparation process. At the raw material end, polyoxyethylene fatty ether phosphate dispersant is used in combination with nanoparticles for targeted modification to reduce particle surface energy and agglomeration tendency. During the preparation process, modified nano-silica sol, nano-zirconia, and nano-aluminum nitride powder are added sequentially using a gradient feeding method. Combined with segmented temperature-controlled stirring and ultrasonic dispersion-ball milling, nanoparticles of different densities and surface properties are uniformly dispersed in the organic resin matrix, avoiding uneven film hardness and light transmittance fluctuations caused by local particle enrichment or vacancies. Finally, a uniform coating layer is formed, which has both high hardness and high light transmittance, meeting the requirements for scratch resistance without affecting the photovoltaic conversion efficiency of photovoltaic modules.

[0021] 3. This invention constructs a strong adhesion system through the synergistic effect of modified epoxy resin and modified nano-silica sol. After carboxylation and siloxane crosslinking modification, the modified epoxy resin introduces more active groups into its molecular chain, which can form multiple chemical bonds with the silanol groups and silane coupling agent groups on the surface of the modified nano-silica sol. At the same time, the silane coupling agent KH-550 acts as a bridge to further strengthen the interfacial bonding force between inorganic particles, organic resin and photovoltaic glass substrate. In addition, the formulation is compounded with ultraviolet absorber UV-327 and antioxidant 1010. The former absorbs outdoor ultraviolet rays, and the latter inhibits resin oxidative degradation. Combined with highly stable inorganic particles, the film layer has excellent resistance to salt spray and wind and sand erosion, and can resist the influence of complex environmental factors such as outdoor temperature and humidity changes and acid and alkali corrosion, reducing the risk of film peeling and cracking, and ensuring long-term protection.

[0022] 4. This invention improves film quality through synergistic regulation of the solvent system and preparation process. The solvent system utilizes a complex of methyl isobutyl ketone, isopropanol, propylene glycol methyl ether acetate, and dipropylene glycol methyl ether. The difference in evaporation gradients of solvents with different boiling points avoids bubbles and pinholes caused by rapid solvent evaporation during film formation. Simultaneously, a polyether-modified polydimethylsiloxane-based silicone leveling agent is added, synergistically reducing the surface tension of the film and improving liquid flowability, thus minimizing appearance defects such as orange peel and pinholes during the coating process. In the preparation process, aging treatment allows unreacted monomers to fully crosslink, further eliminating microbubbles within the system. This ultimately results in a smooth, defect-free coating layer, improving the uniformity of the photovoltaic module's appearance and preventing defects from becoming weak points for corrosion and scratches, thereby extending the film's lifespan. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1: Preparation of anti-scratch coating solution for photovoltaic modules. The specific preparation steps are as follows: S1. Add 18 parts of methyl isobutyl ketone, 8 parts of isopropanol, 3 parts of propylene glycol methyl ether acetate and 2 parts of dipropylene glycol methyl ether to a three-necked flask, stir at 200 r / min and mix at room temperature for 15 min to form a mixed solvent. S2. Slowly add 15 parts of epoxy resin to the above mixed solvent, increase the stirring speed to 400 r / min and heat to 50°C, keep warm and stir for 30 min until the resin is completely dissolved; then add 3 parts of silane coupling agent KH-550 and continue stirring for 20 min to form a premixed solution. S3. Add 25 parts of nano silica sol, 1 part of nano zirconium oxide, and 2 parts of nano aluminum nitride powder to the premixed solution in sequence, adjust the stirring speed to 600 r / min, and stir at room temperature for 1 h; then add 0.8 parts of polyoxyethylene fatty ether phosphate and continue stirring for 30 min. S4. Add 0.5 parts of UV absorber UV-327, 0.2 parts of antioxidant 1010, 1.5 parts of polydimethylsiloxane and 0.1 parts of organosilicon leveling agent to the system. Reduce the stirring speed to 300 r / min and heat to 60℃. Keep the temperature and stir for 40 min to ensure that the additives are evenly dispersed. S5. Add 0.3 parts of dibutyltin dilaurate, maintain the stirring rate at 300 r / min, heat to 70℃, and keep the reaction at this temperature for 1 h. After the reaction is complete, take a sample to test the viscosity at 25℃. If the viscosity is within acceptable limits, cool the system to room temperature and filter under reduced pressure using a 1 μm organic filter membrane. After filtration, transfer the coating solution to a sealed container and let it stand and age for 24 h at 25℃ in the dark to obtain the anti-scratch coating solution for photovoltaic modules.

[0025] Example 2: Preparation of anti-scratch coating solution for photovoltaic modules. The specific preparation steps are as follows: S1. Add 25 parts of methyl isobutyl ketone, 12 parts of isopropanol, 6 parts of propylene glycol methyl ether acetate and 4 parts of dipropylene glycol methyl ether to a three-necked flask, stir at 300 r / min and mix at room temperature for 20 min to form a mixed solvent. S2. Slowly add 22 parts of epoxy resin to the above mixed solvent, increase the stirring speed to 500 r / min and heat to 55°C, keep warm and stir for 40 min until the resin is completely dissolved; then add 5 parts of silane coupling agent KH-550 and continue stirring for 30 min to form a premixed solution. S3. Add 35 parts of nano silica sol, 2.5 parts of nano zirconium oxide, and 4 parts of nano aluminum nitride powder to the premixed solution in sequence, adjust the stirring speed to 700 r / min, and stir at room temperature for 1.5 h; then add 1.5 parts of polyoxyethylene fatty ether phosphate and continue stirring for 45 min. S4. Add 1.2 parts of UV absorber UV-327, 0.5 parts of antioxidant 1010, 3 parts of polydimethylsiloxane and 0.3 parts of silicone leveling agent to the system. Reduce the stirring speed to 400 r / min and heat to 65℃. Keep stirring for 50 min to ensure uniform dispersion of the additives. S5. Add 0.6 parts of dibutyltin dilaurate, maintain the stirring rate at 400 r / min, heat to 75℃, and keep the reaction at this temperature for 1.5 h. After the reaction is completed, take a sample to test the viscosity at 25℃. If the viscosity is within acceptable limits, cool the system to room temperature and filter under reduced pressure using a 1 μm organic filter membrane. After filtration, transfer the coating solution to a sealed container and let it stand and age for 36 h at 25℃ in the dark to obtain the anti-scratch coating solution for photovoltaic modules.

[0026] Example 3: Preparation of anti-scratch coating solution for photovoltaic modules. The specific preparation steps are as follows: S1. Add 21 parts methyl isobutyl ketone, 10 parts isopropanol, 4 parts propylene glycol methyl ether acetate and 3 parts dipropylene glycol methyl ether to a three-necked flask, stir at 250 r / min and mix at room temperature for 17 min to form a mixed solvent. S2. Slowly add 18 parts of epoxy resin to the above mixed solvent, increase the stirring speed to 450 r / min and heat to 52°C, keep warm and stir for 35 min until the resin is completely dissolved; then add 4 parts of silane coupling agent KH-550 and continue stirring for 25 min to form a premixed solution. S3. Add 30 parts of nano silica sol, 1.5 parts of nano zirconium oxide, and 3 parts of nano aluminum nitride powder to the premixed solution in sequence, adjust the stirring speed to 650 r / min, and stir at room temperature for 1.2 h; then add 1 part of polyoxyethylene fatty ether phosphate and continue stirring for 38 min. S4. Add 0.8 parts of UV absorber UV-327, 0.3 parts of antioxidant 1010, 2 parts of polydimethylsiloxane and 0.2 parts of silicone leveling agent to the system. Reduce the stirring speed to 350 r / min and heat to 62℃. Keep the temperature and stir for 45 min to ensure that the additives are evenly dispersed. S5. Add 0.4 parts of dibutyltin dilaurate, maintain the stirring rate at 350 r / min, heat to 72℃, and keep the reaction at this temperature for 1.2 h. After the reaction is completed, take a sample to test the viscosity at 25℃. If the viscosity is within acceptable limits, cool the system to room temperature and filter under reduced pressure using a 1 μm organic filter membrane. After filtration, transfer the coating solution to a sealed container and let it stand and age for 30 h at 25℃ in the dark to obtain the anti-scratch coating solution for photovoltaic modules.

[0027] Example 4: Preparation of modified epoxy resin. The specific preparation steps are as follows: A1. Take 300g of bisphenol A type epoxy resin and add 150mL of methyl isobutyl ketone. Stir at 200r / min and heat to 90℃. Then slowly add 25g of adipic acid and 0.5g of p-toluenesulfonic acid. Heat to 110℃ and keep the reaction at this temperature for 4h. Take a sample every 1h to test the acid value. When the acid value drops to 10mgKOH / g, stop the reaction. Then cool down to 60℃ and add 30mL of isopropanol to dilute, to obtain the first modified carboxylated epoxy resin. A2. Take 200g of the first-modified carboxylated epoxy resin and heat it to 80℃. Add 10g of silane coupling agent KH-550 and 5mL of deionized water, and stir at 400r / min. Then add 0.8g of antioxidant 1010 and 1g of dibutyltin dilaurate. Continue to maintain the temperature and stirring rate, and keep the reaction at this temperature for 3h. During this period, monitor the intensity change of the characteristic peak 1080cm⁻¹ of siloxane by Fourier transform infrared spectroscopy until the peak intensity stabilizes. Stop the reaction, add 20mL of propylene glycol methyl ether acetate to dilute, and cool to 50℃ to obtain the second-modified siloxane crosslinked epoxy resin. A3. Take 180g of the second modified siloxane crosslinked epoxy resin, add 8g of untreated nano-zirconia and 2g of polydimethylsiloxane, and perform high-speed shear dispersion treatment at 8000r / min for 30min. Then transfer it to a ball mill with 5mm diameter agate balls and a ball-to-material ratio of 8:1. Ball mill for 2h to ensure uniform dispersion of nano-zirconia. After ball milling, heat to 70℃, add 1g of ultraviolet absorber UV-327, stir for 1h, and then cool to room temperature. Filter through a 1μm filter membrane to obtain the modified epoxy resin.

[0028] Example 5: Preparation of modified epoxy resin. The specific preparation steps are as follows: A1. Take 350g of bisphenol A type epoxy resin and add 180mL of methyl isobutyl ketone. Stir at 300r / min and heat to 95℃. Then slowly add 30g of adipic acid and 1g of p-toluenesulfonic acid. Heat to 120℃ and keep the reaction at this temperature for 5h. Take a sample every 1h to test the acid value. When the acid value drops to 15mgKOH / g, stop the reaction. Then cool down to 70℃ and add 40mL of isopropanol to dilute, to obtain the first modified carboxylated epoxy resin. A2. Take 250g of the first-modified carboxylated epoxy resin and heat it to 85℃. Add 15g of silane coupling agent KH-550 and 8mL of deionized water, and stir at 500r / min. Then add 1.2g of antioxidant 1010 and 1.5g of dibutyltin dilaurate. Continue to maintain the temperature and stirring rate and keep the reaction at this temperature for 4h. During this period, monitor the intensity change of the characteristic peak 1080cm⁻¹ of siloxane by Fourier transform infrared spectroscopy until the peak intensity stabilizes. Stop the reaction, add 25mL of propylene glycol methyl ether acetate to dilute, and cool to 55℃ to obtain the second-modified siloxane crosslinked epoxy resin. A3. Take 220g of the second modified siloxane crosslinked epoxy resin, add 12g of untreated nano-zirconia and 3g of polydimethylsiloxane, and perform high-speed shear dispersion treatment at 10000r / min for 45min. Then transfer it to a ball mill with 5mm diameter agate balls and a ball-to-material ratio of 8:1. Ball mill for 3h to ensure uniform dispersion of nano-zirconia. After ball milling, heat to 75℃, add 2g of UV absorber UV-327, stir for 1.5h, cool to room temperature, and filter through a 1μm filter membrane to obtain the modified epoxy resin.

[0029] Example 6: Preparation of modified nano-silica sol. The specific preparation steps are as follows: B1. Take 400g of nano-silica sol with a solid content of 30%, add 200mL of isopropanol for dilution, stir at 300r / min and heat to 50℃, then slowly add a mixture of 15g of silane coupling agent KH-560 and 10mL of deionized water, controlling the addition time at 60min; after the addition is complete, heat to 70℃ and keep the reaction at this temperature for 3h, taking samples every 30min to detect particle size changes until the particle size stabilizes at 15nm; after the reaction is complete, cool to room temperature and remove 10% of the solvent by vacuum distillation to obtain the first modified nano-silica sol; B2. Take 300g of the first modified nano silica sol, add 80g of the modified epoxy resin prepared in Example 4, stir at 500r / min and heat to 80℃, then add 2g of dibutyltin dilaurate, and add ethanolamine dropwise to adjust the pH to 7. Then keep the reaction at the temperature for 5h. During this period, monitor the intensity change of the characteristic peak of the epoxy group at 910cm⁻¹ by Fourier transform infrared spectroscopy until the peak intensity decreases by 80%. After the reaction is completed, add 50mL of propylene glycol methyl ether acetate to dilute, and cool to 40℃ to obtain the second modified nano silica sol. B3. Take 250g of the second modified nano-silica sol, add 15g of untreated nano-aluminum nitride powder, and then add 3g of polyoxyethylene fatty ether phosphate. Disperse the mixture using ultrasonic power of 300W for 60min, stopping the machine every 20min for 10min to prevent local overheating. After dispersion, cool to room temperature, add 2g of ultraviolet absorber UV-327, and stir continuously at 300r / min for 40min until uniformly dispersed. Cool to room temperature and filter using a 1μm filter membrane to obtain the modified nano-silica sol.

[0030] Example 7: Preparation of modified nano-silica sol. The specific preparation steps are as follows: B1. Take 500g of nano-silica sol with a solid content of 30%, add 250mL of isopropanol for dilution, stir at 400r / min and heat to 60℃, then slowly add a mixture of 20g of silane coupling agent KH-560 and 15mL of deionized water, controlling the addition time at 90min; after the addition is complete, heat to 75℃ and keep the reaction at this temperature for 4h, taking samples every 30min to detect particle size changes until the particle size stabilizes at 20nm; after the reaction is complete, cool to room temperature and remove 15% of the solvent by vacuum distillation to obtain the first modified nano-silica sol; B2. Take 350g of the first modified nano-silica sol, add 100g of the modified epoxy resin prepared in Example 4, stir at 600r / min and heat to 85℃, then add 3g of dibutyltin dilaurate, and add ethanolamine dropwise to adjust the pH to 8, and then keep the reaction at the temperature for 6h. During this period, monitor the intensity change of the characteristic peak of the epoxy group at 910cm⁻¹ by Fourier transform infrared spectroscopy until the peak intensity decreases by 80%. After the reaction is completed, add 60mL of propylene glycol methyl ether acetate to dilute, and cool to 45℃ to obtain the second modified nano-silica sol. B3. Take 300g of the second modified nano-silica sol, add 20g of untreated nano-aluminum nitride powder, and then add 5g of polyoxyethylene fatty ether phosphate. Disperse the mixture using ultrasonic power of 300W for 90min, stopping the machine every 20min for 10min to prevent local overheating. After dispersion, cool to room temperature, add 3g of ultraviolet absorber UV-327, and stir continuously at 400r / min for 60min until uniformly dispersed. Cool to room temperature and filter using a 1μm filter membrane to obtain the modified nano-silica sol.

[0031] Example 8: Preparation of the nano-zirconia, the specific preparation steps are as follows: 100g of untreated nano-zirconia powder was added to 400g of anhydrous ethanol and ultrasonically dispersed at 250W for 30min. Then, 2g of silane coupling agent KH-570 was added and reacted at 60℃ and 400r / min for 2h. After the reaction was completed, the precipitate was collected by centrifugation and vacuum dried at 90℃ for 3h to obtain the nano-zirconia.

[0032] Example 9: The aluminum nitride powder was prepared using the following specific steps: 100g of untreated nano-aluminum nitride powder was dispersed in 500g of deionized water to form a suspension. 6g of trisodium citrate was added as a dispersant, and the suspension was ultrasonically treated at 350W for 40min. Subsequently, the temperature was raised to 65℃, and 15g of 10% sodium silicate solution was added dropwise. After the addition was complete, the pH was adjusted to 6 with dilute nitric acid, and the mixture was kept at this temperature and stirred for 2.5h. After the reaction was completed, the mixture was centrifuged, and the precipitate was washed four times with deionized water and dried at 110℃ for 5h to obtain the nano-aluminum nitride powder.

[0033] Comparative Example 1: A scratch-resistant coating solution for photovoltaic modules was prepared. The specific preparation steps are as follows: The remaining steps remain unchanged, except that the epoxy resin in Example 3 is replaced with the modified epoxy resin prepared in Example 4 to prepare the anti-scratch coating liquid for photovoltaic modules.

[0034] Comparative Example 2: Preparation of an anti-scratch coating solution for photovoltaic modules. The specific preparation steps are as follows: The remaining steps remain unchanged, except that the nano silica sol in Example 3 is replaced with the modified nano silica sol prepared in Example 7 to prepare the anti-scratch coating liquid for photovoltaic modules.

[0035] Comparative Example 3: A scratch-resistant coating solution for photovoltaic modules was prepared. The specific preparation steps are as follows: The remaining steps remain unchanged, except that the epoxy resin in Example 3 is replaced with the modified epoxy resin prepared in Example 4, and the nano silica sol is replaced with the modified nano silica sol prepared in Example 7, to prepare the anti-scratch coating liquid for photovoltaic modules.

[0036]

[0037] Performance test results show that: in terms of light transmittance (400-800nm), Examples 1-3 are 88.2%-90.8%, while Comparative Examples 1-3 are improved to 91.5%-93.3%; in terms of hardness, Examples 1-2 reach 4H and Example 3 reaches 5H, while Comparative Examples 1-2 are 5H and 6H respectively, and Comparative Example 3 is 6H; in terms of adhesion (cross-cut test), Examples 1-2 are level 2 and Example 3 is level 1, while Comparative Examples 1-3 are all optimized to level 1 or 0; in terms of salt spray resistance (5% NaCl solution), Examples 1-3 are 380-450h, while Comparative Examples 1-3 are improved to 480-550h; in terms of scratch resistance, Examples 1-3 are 6.5%-8.6%, while Comparative Examples 1-3 are reduced to 3.1%-5.2%. Overall, the comparative examples using modified epoxy resin and modified nano-silica sol, especially Comparative Example 3 which uses both, outperformed the examples without modified raw materials in all aspects, indicating that modified raw materials can effectively improve the light transmittance, hardness, adhesion, salt spray resistance and scratch resistance of the coating solution.

[0038] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A scratch-resistant coating liquid for photovoltaic modules, characterized in that: It contains the following raw materials in parts by weight: 18-25 parts methyl isobutyl ketone, 8-12 parts isopropanol, 3-6 parts propylene glycol methyl ether acetate, 2-4 parts dipropylene glycol methyl ether, 15-22 parts modified epoxy resin, 3-5 parts silane coupling agent KH-550, 25-35 parts modified nano silica sol, 1-2.5 parts nano zirconium oxide, 2-4 parts nano aluminum nitride powder, 0.8-1.5 parts polyoxyethylene fatty ether phosphate, 0.5-1.2 parts ultraviolet absorber UV-327, 0.2-0.5 parts antioxidant 1010, 1.5-3 parts polydimethylsiloxane, 0.1-0.3 parts organosilicon leveling agent, and 0.3-0.6 parts dibutyltin dilaurate.

2. The anti-scratch coating liquid for photovoltaic modules according to claim 1, characterized in that: The nano-zirconia is nano-zirconia that has undergone surface pretreatment. The pretreatment steps are as follows: take untreated nano-zirconia powder and add 4 times its mass of anhydrous ethanol, ultrasonically disperse it at 250W for 30min, then add 2% of the mass of nano-zirconia silane coupling agent KH-570, and react for 2h under stirring conditions of 60℃ and 400r / min. After the reaction is completed, centrifuge to separate, collect the precipitate and vacuum dry it at 90℃ for 3h to obtain the nano-zirconia.

3. The anti-scratch coating liquid for photovoltaic modules according to claim 1, characterized in that: The nano-aluminum nitride powder is a coated and modified nano-aluminum nitride. The coating and modification steps are as follows: untreated nano-aluminum nitride powder is dispersed in 5 times its mass of deionized water to form a suspension. 6% by mass of trisodium citrate is added as a dispersant, and the mixture is ultrasonically treated at 350W for 40 minutes. Subsequently, the temperature is raised to 65℃, and 15% by mass of aluminum nitride and 10% sodium silicate solution are added dropwise. After the addition is complete, the pH is adjusted to 6 with dilute nitric acid, and the mixture is kept warm and stirred for 2.5 hours. After the reaction is completed, the mixture is centrifuged, the precipitate is washed 4 times with deionized water, and dried at 110℃ for 5 hours to obtain the nano-aluminum nitride powder.

4. The anti-scratch coating liquid for photovoltaic modules according to claim 1, characterized in that: The modified epoxy resin is prepared using the following specific steps: A1. Take bisphenol A type epoxy resin and add methyl isobutyl ketone. Stir at 200-300 r / min and heat to 90-95℃. Then slowly add adipic acid and p-toluenesulfonic acid and heat to 110-120℃. Keep the temperature for 4-5 hours. Take a sample every 1 hour to detect the acid value. When the acid value drops to 10-15 mg KOH / g, stop the reaction. Then cool down to 60-70℃ and add isopropanol to dilute to obtain the first modified carboxylated epoxy resin. A2. Take the first modified carboxylated epoxy resin, heat it to 80-85℃, add silane coupling agent KH-550 and deionized water, stir at 400-500 r / min, then add antioxidant 1010 and dibutyltin dilaurate, continue to maintain the temperature and stirring rate, and keep the reaction at this temperature for 3-4 hours; during this period, monitor the intensity change of the characteristic peak 1080 cm⁻¹ of siloxane by Fourier transform infrared spectroscopy until the peak intensity stabilizes, then stop the reaction, add propylene glycol methyl ether acetate to dilute, and cool to 50-55℃ to obtain the second modified siloxane crosslinked epoxy resin. A3. Take the second modified siloxane crosslinked epoxy resin, add untreated nano-zirconia and polydimethylsiloxane, and perform high-speed shear dispersion treatment at 8000-10000 r / min for 30-45 min. Then transfer it to a ball mill with 5 mm diameter agate balls and a ball-to-material ratio of 8:

1. Ball mill for 2-3 h to ensure uniform dispersion of nano-zirconia. After ball milling, heat to 70-75℃, add UV absorber UV-327, stir for 1-1.5 h, then cool to room temperature and filter through a 1 μm filter membrane to obtain the modified epoxy resin.

5. The anti-scratch coating liquid for photovoltaic modules according to claim 4, characterized in that: The ratio of bisphenol A type epoxy resin, methyl isobutyl ketone, adipic acid, p-toluenesulfonic acid, and isopropanol in A1 is 300-350g: 150-180mL: 25-30g: 0.5-1g: 30-40mL. The ratio of the first modified carboxylated epoxy resin, silane coupling agent KH-550, deionized water, antioxidant 1010, dibutyltin dilaurate, and propylene glycol methyl ether acetate in A2 is 200-250g: 10-15g: 5-8mL: 0.8-1.2g: 1-1.5g: 20-25mL; The ratio of the second modified siloxane crosslinked epoxy resin, nano-zirconia, polydimethylsiloxane, and ultraviolet absorber UV-327 in A3 is 180-220g: 8-12g: 2-3g: 1-2g.

6. The anti-scratch coating liquid for photovoltaic modules according to claim 1, characterized in that: The modified nano-silica sol is prepared using the following specific steps: B1. Take a nano-silica sol with a solid content of 30%, dilute it with isopropanol, stir at 300-400 r / min and heat to 50-60℃, then slowly add a mixture of silane coupling agent KH-560 and deionized water, controlling the addition time at 60-90 min; after the addition is complete, heat to 70-75℃ and keep the reaction at this temperature for 3-4 h, taking samples every 30 min to detect particle size changes until the particle size stabilizes at 15-20 nm; after the reaction is complete, cool to room temperature and remove 10-15% of the solvent by vacuum distillation to obtain the first modified nano-silica sol; B2. Take the first modified nano-silica sol, add the modified epoxy resin described in claim 4, stir at 500-600 r / min and heat to 80-85℃, then add dibutyltin dilaurate, and add ethanolamine dropwise to adjust the pH to 7-8. Then keep the reaction at the temperature for 5-6 hours. During this period, monitor the intensity change of the characteristic peak of the epoxy group at 910 cm⁻¹ by Fourier transform infrared spectroscopy until the peak intensity decreases by 80%. After the reaction is completed, add propylene glycol methyl ether acetate to dilute, and cool to 40-45℃ to obtain the second modified nano-silica sol. B3. Take the second modified nano-silica sol and add untreated nano-aluminum nitride powder, then add polyoxyethylene fatty ether phosphate ester, and ultrasonically disperse at 300W for 60-90 minutes, stopping the machine every 20 minutes and stirring for 10 minutes to prevent local overheating. After dispersion, cool to room temperature, add UV absorber UV-327, and stir continuously at 300-400 r / min for 40-60 min until uniformly dispersed; After cooling to room temperature, the modified nano-silica sol was obtained by filtration through a 1μm filter membrane.

7. The anti-scratch coating liquid for photovoltaic modules according to claim 6, characterized in that: The ratio of nano-silica sol, isopropanol, silane coupling agent KH-560, and deionized water in B1 is 400-500g: 200-250mL: 15-20g: 10-15mL. The ratio of the first modified nano-silica sol, modified epoxy resin, dibutyltin dilaurate, and propylene glycol methyl ether acetate in B2 is 300-350g: 80-100g: 2-3g: 50-60mL. The ratio of the second modified nano-silica sol, nano-aluminum nitride powder, polyoxyethylene fatty ether phosphate, and ultraviolet absorber UV-327 in B3 is 250-300g: 15-20g: 3-5g: 2-3g.

8. A method for preparing an anti-scratch coating liquid for photovoltaic modules, characterized in that: Specifically, it includes the following steps: S1. Add methyl isobutyl ketone, isopropanol, propylene glycol methyl ether acetate and dipropylene glycol methyl ether to a three-necked flask, stir at 200-300 r / min, and mix at room temperature for 15-20 min to form a mixed solvent. S2. Slowly add the modified epoxy resin to the above mixed solvent, increase the stirring speed to 400-500 r / min and heat to 50-55℃, keep warm and stir for 30-40 min until the resin is completely dissolved; then add the silane coupling agent KH-550 and continue stirring for 20-30 min to form a premixed solution. S3. Add the modified nano-silica sol, nano-zirconia, and nano-aluminum nitride powder to the premixed solution in sequence, adjust the stirring speed to 600-700 r / min, and stir at room temperature for 1-1.5 h; then add polyoxyethylene fatty ether phosphate and continue stirring for 30-45 min. S4. Add UV absorber UV-327, antioxidant 1010, polydimethylsiloxane and organosilicon leveling agent to the system. Reduce the stirring speed to 300-400 r / min and raise the temperature to 60-65℃. Keep the temperature and stir for 40-50 min to ensure that the additives are evenly dispersed. S5. Add dibutyltin dilaurate, maintain the stirring rate at 300-400 r / min, heat to 70-75℃, and keep the reaction at this temperature for 1-1.5 h. After the reaction is complete, take a sample to test the viscosity at 25℃. If the viscosity is within acceptable limits, cool the system to room temperature and filter under reduced pressure using a 1 μm organic filter membrane. After filtration, transfer the coating solution to a sealed container and let it stand and age at 25℃ in the dark for 24-36 h to obtain the anti-scratch coating solution for photovoltaic modules.

9. The method for preparing an anti-scratch coating liquid for photovoltaic modules according to claim 8, characterized in that: In the S5 viscosity test, if the viscosity is too high, add an appropriate amount of methyl isobutyl ketone to adjust it; if the viscosity is too low, remove a small amount of solvent by vacuum distillation.

Images