Preparation method of metal plate imitating BIPV photovoltaic glass

Abstract

The application provides a preparation method of metal-imitating plate BIPV photovoltaic glass and belongs to the technical field of glass materials, and comprises the following steps: butyl acetate, nano cerium oxide and a dispersing agent are ground and pre-dispersed, polyurethane dipropylene acrylate, TPGDA and a photoinitiator are uniformly stirred, flaky interference pigments and EVA wax paste are added, the spraying viscosity is adjusted, metal-imitating interference coating is obtained, metal-imitating interference coating bottom spraying is performed, after leveling, UV curing is performed under N2 protection, a bottom metal-imitating interference coating layer is formed; isopropyl alcohol, TEOS, TMOS and TBOS are mixed, a mixed solution of hydrochloric acid and deionized water is added dropwise, hydrolysis is performed, closed aging is performed, and silane sol is obtained; the photovoltaic glass substrate with the coating layer is immersed in the silane sol, is pulled out, gradient curing is performed, cooling is performed, and the metal-imitating plate BIPV photovoltaic glass is obtained. The metal-imitating plate BIPV photovoltaic glass can realize the metal-imitating texture effect under the premise of maintaining high light transmittance.

Description

Technical Field

[0001] This invention relates to the field of glass materials technology, and specifically to a method for preparing metal-like BIPV photovoltaic glass. Background Technology

[0002] BIPV photovoltaic glass, also known as BIPV glass or photovoltaic glass, is a special type of glass specifically designed for Building Integrated Photovoltaics. It not only possesses the light transmission and insulation functions of ordinary glass, but also embeds or composites photovoltaic cells into the glass structure through a special process, thereby achieving power generation. BIPV photovoltaic glass not only generates electricity to provide green energy, but also blends seamlessly with the building structure, adding to its style and aesthetics. Meanwhile, imitation metal glass, also called imitation metallic glass, has a metallic-like color and luster, making it a type of glass with a metallic texture. It can replace traditional metal curtain walls and is highly favored in the architectural glass market. If BIPV glass could be combined with imitation metal glass, giving it both power generation capabilities and a metallic-like appearance, it would undoubtedly have a promising market prospect. Currently, there are two main paths to achieve the metallic effect in photovoltaic glass: one is magnetron sputtering of multilayer dielectric films, which presents structural colors through optical interference, but this approach involves large equipment investment, complex processes, and high energy consumption; the other is high-temperature glaze sintering, which involves melting metal oxides or mica titanium pearlescent pigments with glass powder to form a glaze layer, but the sintering temperature is as high as 1000℃ or more, which not only consumes a lot of energy but also easily leads to a decrease in the tempering of photovoltaic glass. Furthermore, the glaze layer is thick and severely blocks light, resulting in extremely low visible light transmittance, making it difficult to meet the requirements of photovoltaic glass that requires high transmittance.

[0003] Furthermore, achieving both high light transmittance and a metallic finish has always been a core challenge for decorative coatings on photovoltaic glass. A metallic finish requires sufficient directional specular reflection, but this inevitably reduces light transmittance. Traditional coatings often require large amounts of aluminum powder or pearlescent pigments, resulting not only in low directional specular reflection but also significant light loss and haze. Therefore, achieving a good metallic gloss (≥85 GU) while maintaining high visible light transmittance (≥80%) is a pressing technical challenge for realizing truly metallic-looking photovoltaic glass.

[0004] In addition, the surfaces of the two types of inorganic rigid coatings, namely magnetron sputtering interference film and high-temperature glaze, generally exhibit high surface energy and microscopic hydrophilicity, making them prone to adsorbing dust particles and oil stains in the urban atmosphere. During long-term outdoor service, the dirt accumulated on the glass surface will further affect the sunlight transmittance. Summary of the Invention

[0005] In view of this, the present invention provides a method for preparing a metal-like BIPV photovoltaic glass, which can achieve a metal-like texture effect while maintaining the high light transmittance of the photovoltaic glass, and improve the hydrophobic properties of the glass surface.

[0006] To achieve the above objectives, the specific solution of the present invention is as follows: a method for preparing metal-plate-like BIPV photovoltaic glass, comprising the following preparation steps: S1. Take butyl acetate, nano-cerium oxide and dispersant and grind and pre-disperse them. Add polyurethane diacrylate, TPGDA and photoinitiator and stir evenly. Add silver flake interference pigment and EVA wax paste, stir at low speed, adjust the spraying viscosity with butyl acetate, degas, filter and obtain the imitation metal interference coating. S2. After oxygen plasma treatment of the photovoltaic glass substrate, a metal interference-like coating is sprayed onto the substrate. After leveling, it is UV cured under N2 protection to form a metal interference-like coating on the surface of the photovoltaic glass substrate. S3. Mix isopropanol, TEOS, TMOS, and TBOS, add a mixture of hydrochloric acid and deionized water, stir at a constant temperature for hydrolysis, and then age in a sealed container to obtain silane sol. S4. Immerse the photovoltaic glass substrate with the underlying imitation metal interference coating into silane sol, pull it out, perform gradient curing, and cool it to obtain the imitation metal plate BIPV photovoltaic glass.

[0007] After pre-dispersing nano-cerium oxide through grinding, TPGDA (tripropylene glycol diacrylate) is used as an active diluent. EVA wax paste is adsorbed onto the surface of the interference pigment through hydrogen bonds and van der Waals forces to form a thin lubricating film, reducing inter-plate friction and thus maintaining the integrity of the pigment structure. In addition, the addition of nano-cerium oxide imparts ultraviolet blocking function.

[0008] The metal-like interference coating prepared by this invention is applied by spraying atomized droplets onto a glass surface. The pigment flakes are randomly oriented within the droplets. During the leveling period, the continuous evaporation of the solvent causes the film to shrink, generating a compressive force perpendicular to the substrate, which pushes the pigment flakes to lie horizontally. Finally, the steric hindrance effect of the EVA wax paste prevents direct contact or aggregation between the pigment flakes. Gravitational settling torque preferentially orients large-diameter pigment flakes, and capillary force "flattens" the pigment flakes onto the substrate during the later stages of solvent evaporation, thus completing the pigment flake orientation. Finally, UV curing is used for shaping. Chain polymerization is initiated by a photoinitiator, and oxygen inhibition is suppressed by nitrogen protection, ultimately achieving complete surface curing. This permanently fixes the horizontal orientation of the pigment flakes, thereby forming a bottom layer of metal-like interference coating with a large number of directional specular reflections on the surface of the photovoltaic glass substrate. In this underlying metallic interference coating, the pigment flakes are oriented, requiring only a small amount of pigment to create numerous directional specular reflections, resulting in very low pigment demand. Most of the coating is made of transparent resin, allowing light to pass through unimpeded. The semi-transparent silver-white flake-shaped interference pigments prevent some light from being reflected or absorbed, allowing it to pass directly through the pigment flakes and ensuring high visible light transmittance. Simultaneously, the countless flat pigment flakes act like numerous parallel semi-transparent nanomirrors, collectively producing strong and directional specular reflections of incident visible light, resulting in a clean, bright silver-white metallic luster. This achieves a metallic luster effect of over 85 GU while maintaining the high light transmittance of photovoltaic glass, allowing more than 80% of visible light to pass through the coating and be utilized by the photovoltaic cells, thus presenting a good silver-white metallic texture.

[0009] By employing the synergistic hydrolysis of ternary silane precursors TMOS (methyl orthosilicate), TEOS (ethyl orthosilicate), and TBOS (butyl orthosilicate), TMOS, containing methoxy groups, exhibits lower steric hindrance and faster hydrolysis, preferentially forming highly active Si(OH)4 monomers that rapidly condense into short-chain dense oligomers. TEOS, containing ethoxy groups, has a moderate hydrolysis rate and serves as the main body for continuously expanding the siloxane network. TBOS, containing butoxy groups, has higher steric hindrance and hydrolyzes the slowest. In the preparation of silane sols, TMOS and TEOS hydrolyze relatively easily, forming the initial network framework first, while TBOS hydrolyzes slowly later. Its long butyl segments spatially hinder the complete condensation of the network in this region, thus pre-embedding mesoporous "templates." Under acidic conditions, the hydrolysis rate is much greater than the condensation rate, resulting in the formation of linear or low-branched chains in the system, maintaining good fluidity and film-forming properties, and obtaining stable silane sols. In the subsequent immersion and pull-out of the photovoltaic glass substrate in silane sol, the uniformity of the film formation is improved by the coupling effect of gravity drainage, surface tension gradient, and evaporative cooling during the pulling process. Then, through gradient curing, the silanol groups are further condensed into a Si-O-Si network. At the same time, during the heating curing process, the low surface energy TBOS butoxy segments spontaneously migrate to the coating-air interface, and the residual butoxy groups in the TBOS micro-regions are further hydrolyzed to generate butanol. The butanol and solvent evaporate and leave nanoscale pores in the silica gel network, thereby increasing the surface roughness. The TMOS-dominated network near the bottom is completely hydrolyzed and further solidified and densified, thus forming a gradient refractive index SiO2 film layer with a dense bottom and a loose and porous top. Its refractive index gradually decreases from the bottom to the top, thereby reducing the reflection loss when light shines from the top of the coating into the air, and allowing more light passing through the inside of the coating to enter the coating, further improving the light transmittance. Furthermore, due to incomplete hydrolysis of TBOS, the low surface energy butoxy segments spontaneously migrate to the coating-air interface, forming a hydrophobic "brush layer" on the surface. This layer works in conjunction with the surface nano-roughness formed by the nano-pores, thereby improving the hydrophobicity of the glass surface without the need for additional fluorine-containing modifiers, giving the glass a self-cleaning function. At the same time, the top protective layer can also act as a physical barrier to protect the underlying metal-like interference coating.

[0010] Furthermore, this technical solution eliminates the need for magnetron sputtering or high-temperature sintering of glazes. By applying spraying and UV curing to the bottom layer of the photovoltaic glass substrate and using immersion lifting and gradient curing processes to the top layer, the entire process is compatible with conventional glass production lines. Overall, the operation is simple, economical, and environmentally friendly.

[0011] Preferably, in step S1, the photoinitiator is a mixture of photoinitiator 184 and photoinitiator TPO; and the dispersant is BYK-2151 dispersant.

[0012] In the imitation metal interference coating, photoinitiator 184 and TPO absorb ultraviolet photons and transition to an excited state. α-cleavage generates benzoyl radicals and phosphonyl radicals, which open the acrylate double bonds, initiating chain polymerization. Nitrogen protection inhibits oxygen polymerization, ultimately achieving complete surface curing. Simultaneously, the long-wavelength absorption (>380nm) of TPO compensates for the insufficient deep penetration of initiator 184, thus achieving synergistic curing of the "surface" and "deep" layers. This allows the coating to transform from a liquid state to a dense, hard, solid three-dimensional cross-linked network within seconds, promoting the fixation of oriented pigment flakes.

[0013] Preferably, in step S1, 60% of the amount of butyl acetate, nano-cerium oxide, and dispersant are added to a sand mill and pre-dispersed using 0.3mm zirconium beads in a circulating mill. The mixture is then transferred to a paint mixing tank, where polyurethane diacrylate, TPGDA, and a photoinitiator are added at 200-300 rpm. The mixture is stirred until homogeneous, and the speed is reduced to 100-150 rpm. Silver-white flake interference pigment and EVA wax are slowly added, and the mixture is stirred at low speed. The remaining 40% of the amount of butyl acetate is used to adjust the spraying viscosity to 25°C. The mixture is then coated with a Forco-4 cup for 30-40 seconds, degassed under vacuum, and filtered through a 200-mesh filter to obtain a metallic interference coating.

[0014] By employing the high shear force generated by a sand mill, the anchoring groups (carboxyl and amine groups) in the dispersant molecules are adsorbed onto the CeO2 surface. The solvated segments form a steric hindrance layer around the particles, effectively preventing re-agglomeration, thus obtaining a stable and transparent nano-CeO2 dispersion. The flake-like interference pigments are shear-sensitive particles; laminar flow stirring at 100-150 rpm only provides macroscopic uniformity without damaging the pigments. Furthermore, EVA wax paste is adsorbed onto the pigment surface through hydrogen bonds and van der Waals forces, forming a thin lubricating film that reduces inter-flake friction, thereby maintaining the integrity of the pigment structure. Low-speed stirring further promotes the pre-adsorption of EVA wax paste.

[0015] Among them, nano-cerium oxide can be purchased from Xuancheng Jingrui New Materials Co., Ltd., with a particle size of 10nm; EVA wax paste (ethylene-vinyl acetate copolymer wax paste) can be purchased from BYK, with a solid content of 20±2%; silver-white flake interference pigment can be purchased from Merck (Merck KGaA), silver-white interference color, synthetic fluorophlogopite-based, D50=15μm.

[0016] Preferably, the simulated metal interference coating comprises the following raw materials in parts by weight: 14-18 parts butyl acetate, 0.6-1 parts nano-cerium oxide, 0.2-0.4 parts BYK-2151 dispersant, 40-45 parts polyurethane diacrylate, 30-35 parts TPGDA, 2-3 parts photoinitiator 184, 0.3-0.6 parts photoinitiator TPO, 2.0-2.5 parts silver-white flake interference pigment, and 0.3-0.5 parts EVA wax paste.

[0017] Preferably, in step S2, after the embossed photovoltaic glass substrate is treated with oxygen plasma, it is coated with two wet-on-wet sprays using an automatic spray gun with a nozzle of 1.3mm and an atomizing pressure of 0.07MPa, with a 3-second flash-dry interval. Then, it is leveled in a 50℃ infrared oven for 5 minutes, and finally cured under N2 protection using a UV curing machine with a radiation energy of 1200mJ / cm². 2 The irradiation time is about 10-15 seconds, thereby forming a bottom layer of metal-like interference coating on the surface of the photovoltaic glass substrate.

[0018] Low-temperature leveling ensures that the evaporation rate of butyl acetate (boiling point 126℃) is moderate at 50℃, avoiding bubbles or orange peel on the surface caused by violent boiling. At the same time, infrared radiation heats from the inside, allowing the solvent to diffuse evenly and promoting full leveling and uniformity of the coating.

[0019] Preferably, the oxygen plasma treatment process in step S2 is as follows: the embossed photovoltaic glass substrate is subjected to oxygen plasma treatment for 90 seconds under the conditions of power 300W and O2 flow rate 50sccm.

[0020] By bombarding the glass surface with high-energy oxygen plasma, the Si-O-Si bonds on the surface are broken, and a large number of active silanol groups (Si-OH) are introduced. The active hydroxyl groups provide chemical bonding sites for the underlying UV coating, thereby improving the coating adhesion.

[0021] Preferably, in step S2, before subjecting the embossed photovoltaic glass substrate to oxygen plasma treatment, it is first ultrasonically cleaned at 50°C for 10 minutes with an alkaline cleaning agent of pH=11-12, rinsed with deionized water, and then dried with hot air. This cleans the substrate surface thoroughly, preventing the introduction of impurities and facilitating coating adhesion.

[0022] Preferably, in step S3, isopropanol, TEOS, TMOS, and TBOS are mixed and stirred, and a mixture of 0.1 mol / L hydrochloric acid and deionized water is added dropwise. The mixture is stirred at a constant temperature of 40°C for 2 hours and then aged in a sealed container for 24 hours to obtain a silane sol.

[0023] Preferably, in the silane sol, the mass ratio of TEOS, TMOS and TBOS is (38-43):(11-14):(8-11).

[0024] Preferably, in step S4, the photovoltaic glass substrate with the underlying imitation metal interference coating is immersed in silane sol, held for 30 seconds, and then smoothly pulled out and transferred to an oven for gradient curing. The temperature is increased to 180°C at a gradient of 2°C / min, held for 60 minutes, and then cooled to room temperature to obtain the imitation metal plate BIPV photovoltaic glass.

[0025] The photovoltaic glass substrate is immersed in silane sol and held for 30 seconds before being smoothly pulled out. This process promotes the uniformity of the liquid film formation under the coupling effect of gravity drainage, surface tension gradient, and evaporative cooling. Then, through gradient curing and heating, the silanol groups (Si-OH) are further condensed into a Si-O-Si network, and the solvent and water are fully evaporated, resulting in condensation and densification.

[0026] The above-described technical solution of the present invention has at least the following beneficial effects: This invention prepares a metallic-like interference coating by spraying atomized droplets onto a glass surface. During the leveling period, the continuous evaporation of the solvent causes the film to shrink, pushing the pigment flakes to lie horizontally. Finally, the spatial steric hindrance effect of EVA wax and the gravitational settling torque preferentially orient the large-diameter pigment flakes. In the later stage of solvent evaporation, capillary force "flattens" the pigment flakes onto the substrate, thus completing the orientation. Finally, UV curing and shaping are used, and nitrogen protection is used to inhibit oxygen polymerization, ultimately achieving complete surface curing. This permanently fixes the horizontal orientation of the pigment flakes. The numerous flat pigment flakes act like numerous parallel semi-transparent nanomirrors, producing strong and directional reflection. Thus, only a small amount of flake-shaped interference pigment is needed to produce a clean, bright silver-white metallic luster. At the same time, most areas of the coating are transparent resin, allowing light to pass through unimpeded. The use of semi-transparent silver-white flake-shaped interference pigment allows some light to directly penetrate the pigment, thus maintaining the overall high light transmittance. This achieves a silver-white metallic texture while maintaining the high light transmittance of photovoltaic glass.

[0027] The top protective layer of this invention employs the synergistic hydrolysis of ternary silane precursors TMOS, TEOS, and TBOS, utilizing the difference in alkyl chain length among the three to regulate hydrolysis and condensation, forming a gradient refractive index SiO2 film layer with a dense bottom and a loose, porous top. Its refractive index gradually decreases from bottom to top, thereby reducing the reflection loss of light when it shines from the top of the coating into the air, and also allowing more light passing through the interior of the coating to enter the coating, further improving the light transmittance.

[0028] 3. This invention combines a bottom layer of coloring and a top layer of protection on the surface of the glass substrate. The combined effect balances photovoltaic absorption and achieves a metallic appearance. The top protective layer also protects the bottom metallic interference coating, making the metallic coating more durable and improving surface hydrophobicity. Furthermore, by using spraying and UV curing on the bottom layer of the photovoltaic glass substrate and immersion lifting and gradient curing on the top layer, the entire process can be adapted to conventional glass production lines. The overall operation is simple, economical, and environmentally friendly. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. The described embodiments are some embodiments of the present invention, and all other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0030] In the following examples and comparative examples, the nano-cerium oxide used, CAS number 1306-38-3, was purchased from Xuancheng Jingrui New Materials Co., Ltd., model JR-CeO2-10, with a particle size of 10nm; The EVA wax paste used (ethylene-vinyl acetate copolymer wax paste), CAS number 24937-78-8 (EVA copolymer), was purchased from BYK Chemicals, model BYK CERAFLOUR 920, with a solid content of 20±2%; The silver-white flake interference pigment used was purchased from Merck (Merck KGaA), Iriodin 100 series, silver-white interference color, synthetic fluorophlogopite-based, D50=15μm.

[0031] Example 1: Take 8.4 kg of butyl acetate, 0.6 kg of nano-cerium oxide, and 0.2 kg of BYK-2151 dispersant, put them into a sand mill (0.3 mm zirconium beads), and circulate and grind for 30 min for pre-dispersion. Sand mill until the fineness is ≤5 μm, transfer to a paint mixing tank, add 40 kg of polyurethane diacrylate, 30 kg of TPGDA (tripropylene glycol diacrylate), 2.0 kg of photoinitiator 184, and 0.3 kg of photoinitiator TPO at 200 rpm, stir for 15 min until uniform, reduce the speed to 100 rpm, slowly add 2.0 kg of silver-white flake interference pigment and 0.3 kg of EVA wax paste, stir at low speed for 20 min, and adjust to the spraying viscosity (25℃, Ford cup 4, 30-40 s) with the remaining 5.6 kg of butyl acetate. Vacuum degassing and filter with 200 mesh to obtain the imitation metal interference coating.

[0032] The embossed photovoltaic glass substrate was ultrasonically cleaned for 10 minutes at 50℃ using an alkaline cleaning agent with pH=11, rinsed with deionized water, and dried with hot air. Then, it underwent oxygen plasma treatment for 90 seconds at a power of 300W and an O2 flow rate of 50sccm to obtain a pretreated glass substrate. A metallic interference coating undercoat was then applied using an HVLP automatic spray gun with a 1.3mm nozzle and an atomizing pressure of 0.07MPa, performing two wet-on-wet sprays with a 3-second flash-dry interval, resulting in a total wet film thickness of 25μm. After leveling in a 50℃ infrared oven for 5 minutes, it was cured under N2 protection using a UV curing machine (365+395nm mixed light source) with a radiation energy of 1200mJ / cm². 2(UV-A band) Irradiation time of 10s for curing to form a bottom layer of metal-like interference coating with a dry film thickness of about 10μm on the surface of photovoltaic glass substrate.

[0033] Mix 7.5L of isopropanol, 190g of TEOS, 55g of TMOS, and 40g of TBOS and stir for 15 minutes. Slowly add a mixture of 0.4L of 0.1mol / L hydrochloric acid and 1.4L of deionized water. Hydrolyze at a constant temperature of 40℃ for 2 hours and then age in a sealed container for 24 hours to obtain silane sol.

[0034] A photovoltaic glass substrate with a bottom layer of simulated metal interference coating is immersed in silane sol at a speed of 3 mm / s, held for 30 seconds, and then smoothly pulled out and transferred to an oven for baking. The temperature is increased to 180°C at a gradient of 2°C / min, held for 60 minutes, and then cooled to room temperature. This forms a top protective layer with a thickness of about 120 nm on the bottom layer of simulated metal interference coating, resulting in simulated metal plate BIPV photovoltaic glass.

[0035] Example 2: Take 10.8 kg of butyl acetate, 1.0 kg of nano-cerium oxide, and 0.4 kg of BYK-2151 dispersant, put them into a sand mill (0.3 mm zirconium beads), and circulate and grind for 30 min for pre-dispersion. Sand mill until the fineness is ≤5 μm, transfer to a paint mixing tank, add 45 kg of polyurethane diacrylate, 35 kg of TPGDA (tripropylene glycol diacrylate), 3.0 kg of photoinitiator 184, and 0.6 kg of photoinitiator TPO at 300 rpm, stir for 15 min until uniform, reduce the speed to 150 rpm, slowly add 2.5 kg of silver-white flake interference pigment and 0.5 kg of EVA wax paste, stir at low speed for 20 min, and adjust to the spraying viscosity (25℃, Ford cup 4, 30-40 s) with the remaining 7.2 kg of butyl acetate. Vacuum degassing and filter with 200 mesh to obtain the imitation metal interference coating.

[0036] The embossed photovoltaic glass substrate was ultrasonically cleaned for 10 minutes at 50℃ using an alkaline cleaning agent with pH=12, rinsed with deionized water, and dried with hot air. Then, it underwent oxygen plasma treatment for 90 seconds at a power of 300W and an O2 flow rate of 50sccm to obtain a pretreated glass substrate. A metallic interference coating undercoat was then applied using an HVLP automatic spray gun with a 1.3mm nozzle and an atomizing pressure of 0.07MPa, performing two wet-on-wet sprays with a 3-second flash-dry interval, resulting in a total wet film thickness of 35μm. After leveling in a 50℃ infrared oven for 5 minutes, it was cured under N2 protection using a UV curing machine (365+395nm mixed light source) with a radiation energy of 1200mJ / cm². 2 (UV-A band) Irradiation time is about 15 seconds for curing, thereby forming a bottom layer of metal-like interference coating with a dry film thickness of about 10μm on the surface of photovoltaic glass substrate.

[0037] Mix 8.5L of isopropanol, 215g of TEOS, 70g of TMOS, and 55g of TBOS and stir for 15 minutes. Slowly add a mixture of 0.6L of 0.1mol / L hydrochloric acid and 1.6L of deionized water. Hydrolyze at a constant temperature of 40℃ for 2 hours and then age in a sealed container for 24 hours to obtain silane sol.

[0038] A photovoltaic glass substrate with a bottom layer of simulated metal interference coating is immersed in silane sol at a speed of 5 mm / s, held for 30 seconds, and then smoothly pulled out and transferred to an oven for baking. The temperature is increased to 180°C at a gradient of 2°C / min, held for 60 minutes, and then cooled to room temperature. This forms a top protective layer with a thickness of about 120 nm on the bottom layer of simulated metal interference coating, resulting in simulated metal plate BIPV photovoltaic glass.

[0039] Example 3: Take 9.6 kg of butyl acetate, 0.8 kg of nano-cerium oxide, and 0.3 kg of BYK-2151 dispersant, put them into a sand mill (0.3 mm zirconium beads), and circulate and grind for 30 min for pre-dispersion. Sand mill until the fineness is ≤5 μm, transfer to a paint mixing tank, add 44 kg of polyurethane diacrylate, 32 kg of TPGDA (tripropylene glycol diacrylate), 2.5 kg of photoinitiator 184, and 0.5 kg of photoinitiator TPO at 250 rpm, stir for 15 min until uniform, reduce the speed to 120 rpm, slowly add 2.3 kg of silver-white flake interference pigment and 0.4 kg of EVA wax paste, stir at low speed for 20 min, and adjust to the spraying viscosity (25℃, Ford cup 4, 30-40 s) with the remaining 6.4 kg of butyl acetate. Vacuum degassing and filter with 200 mesh to obtain the imitation metal interference coating.

[0040] The embossed photovoltaic glass substrate was ultrasonically cleaned for 10 minutes at 50℃ using an alkaline cleaning agent with pH=12, rinsed with deionized water, and dried with hot air. Then, it underwent oxygen plasma treatment for 90 seconds at a power of 300W and an O2 flow rate of 50sccm to obtain a pretreated glass substrate. A metallic interference coating undercoat was then applied using an HVLP automatic spray gun with a 1.3mm nozzle and an atomizing pressure of 0.07MPa, performing two wet-on-wet sprays with a 3-second flash-dry interval, resulting in a total wet film thickness of 30μm. After leveling in a 50℃ infrared oven for 5 minutes, it was cured under N2 protection using a UV curing machine (365+395nm mixed light source) with a radiation energy of 1200mJ / cm². 2 (UV-A band) Irradiation time is about 13s for curing, thereby forming a bottom layer of metal-like interference coating with a dry film thickness of about 10μm on the surface of photovoltaic glass substrate.

[0041] Mix 8.0 L of isopropanol, 208.3 g of TEOS, 60.9 g of TMOS, and 48.1 g of TBOS and stir for 15 min. Slowly add a mixture of 0.5 L of 0.1 mol / L hydrochloric acid and 1.5 L of deionized water. Hydrolyze at 40 °C with stirring for 2 h. Then, age in a sealed container for 24 h to obtain silane sol.

[0042] A photovoltaic glass substrate with a bottom layer of simulated metal interference coating is immersed in silane sol at a speed of 4 mm / s, held for 30 seconds, and then smoothly pulled out and transferred to an oven for baking. The temperature is increased to 180°C at a gradient of 2°C / min, held for 60 minutes, and then cooled to room temperature. This forms a top protective layer with a thickness of about 120 nm on the bottom layer of simulated metal interference coating, resulting in simulated metal BIPV photovoltaic glass.

[0043] Example 4: Take 9.6 kg of butyl acetate, 0.8 kg of nano-cerium oxide, and 0.3 kg of BYK-2151 dispersant, put them into a sand mill (0.3 mm zirconium beads), and circulate and grind for 30 min for pre-dispersion. Sand mill until the fineness is ≤5 μm, transfer to a paint mixing tank, add 43 kg of polyurethane diacrylate, 32 kg of TPGDA (tripropylene glycol diacrylate), 2.5 kg of photoinitiator 184, and 0.5 kg of photoinitiator TPO at 250 rpm, stir for 15 min until uniform, reduce the speed to 120 rpm, slowly add 2.2 kg of silver-white flake interference pigment and 0.4 kg of EVA wax paste, stir at low speed for 20 min, and adjust to the spraying viscosity (25℃, Ford cup 4, 30-40 s) with the remaining 6.4 kg of butyl acetate. Vacuum degassing and filter with 200 mesh to obtain the imitation metal interference coating.

[0044] The embossed photovoltaic glass substrate was ultrasonically cleaned for 10 minutes at 50℃ using an alkaline cleaning agent with pH=12, rinsed with deionized water, and dried with hot air. Then, it underwent oxygen plasma treatment for 90 seconds at a power of 300W and an O2 flow rate of 50sccm to obtain a pretreated glass substrate. A metallic interference coating undercoat was then applied using an HVLP automatic spray gun with a 1.3mm nozzle and an atomizing pressure of 0.07MPa, performing two wet-on-wet sprays with a 3-second flash-dry interval, resulting in a total wet film thickness of 30μm. After leveling in a 50℃ infrared oven for 5 minutes, it was cured under N2 protection using a UV curing machine (365+395nm mixed light source) with a radiation energy of 1200mJ / cm². 2 (UV-A band) Irradiation time is about 13s for curing, thereby forming a bottom layer of metal-like interference coating with a dry film thickness of about 10μm on the surface of photovoltaic glass substrate.

[0045] Mix 8.0 L of isopropanol, 208.3 g of TEOS, 60.9 g of TMOS, and 48.1 g of TBOS and stir for 15 min. Slowly add a mixture of 0.6 L of 0.1 mol / L hydrochloric acid and 1.4 L of deionized water. Hydrolyze at 40 °C with stirring for 2 h. Then, age in a sealed container for 24 h to obtain silane sol.

[0046] A photovoltaic glass substrate with a bottom layer of simulated metal interference coating is immersed in silane sol at a speed of 4 mm / s, held for 30 seconds, and then smoothly pulled out and transferred to an oven for baking. The temperature is increased to 180°C at a gradient of 2°C / min, held for 60 minutes, and then cooled to room temperature. This forms a top protective layer with a thickness of about 120 nm on the bottom layer of simulated metal interference coating, resulting in simulated metal BIPV photovoltaic glass.

[0047] Example 5: Take 9.6 kg of butyl acetate, 0.8 kg of nano-cerium oxide, and 0.3 kg of BYK-2151 dispersant, put them into a sand mill (0.3 mm zirconium beads), and circulate and grind for 30 min for pre-dispersion. Sand mill until the fineness is ≤5 μm, transfer to a paint mixing tank, add 44 kg of polyurethane diacrylate, 33 kg of TPGDA (tripropylene glycol diacrylate), 2.5 kg of photoinitiator 184, and 0.5 kg of photoinitiator TPO at 250 rpm, stir for 15 min until uniform, reduce the speed to 130 rpm, slowly add 2.3 kg of silver-white flake interference pigment and 0.4 kg of EVA wax paste, stir at low speed for 20 min, and adjust to the spraying viscosity (25℃, Ford cup 4, 30-40 s) with the remaining 6.4 kg of butyl acetate. Vacuum degassing and filter with 200 mesh to obtain the imitation metal interference coating.

[0048] The embossed photovoltaic glass substrate was ultrasonically cleaned for 10 minutes at 50℃ using an alkaline cleaning agent with pH=11, rinsed with deionized water, and dried with hot air. Then, it underwent oxygen plasma treatment for 90 seconds at a power of 300W and an O2 flow rate of 50 sccm to obtain a pretreated glass substrate. A metallic interference coating undercoat was then applied using an HVLP automatic spray gun with a 1.3mm nozzle and an atomizing pressure of 0.07MPa, performing two wet-on-wet sprays with a 3-second flash-dry interval, resulting in a total wet film thickness of 30μm. After leveling in a 50℃ infrared oven for 5 minutes, it was cured under N2 protection using a UV curing machine (365+395nm mixed light source) with a radiation energy of 1200mJ / cm². 2 (UV-A band) Irradiation time is about 12s for curing, thereby forming a bottom layer of metal-like interference coating with a dry film thickness of about 10μm on the surface of photovoltaic glass substrate.

[0049] Mix 8.0 L of isopropanol, 208.3 g of TEOS, 60.9 g of TMOS, and 48.1 g of TBOS and stir for 15 min. Slowly add a mixture of 0.4 L of 0.1 mol / L hydrochloric acid and 1.6 L of deionized water. Hydrolyze at 40 °C with stirring for 2 h. Then, age in a sealed container for 24 h to obtain silane sol.

[0050] A photovoltaic glass substrate with a bottom layer of simulated metal interference coating is immersed in silane sol at a speed of 3.5 mm / s, held for 30 seconds, and then smoothly pulled out and transferred to an oven for baking. The temperature is increased to 180°C at a gradient of 2°C / min, held for 60 minutes, and then cooled to room temperature. This forms a top protective layer with a thickness of about 120 nm on the bottom layer of simulated metal interference coating, resulting in simulated metal BIPV photovoltaic glass.

[0051] The present invention also includes the following comparative experiments. Comparative Example 1: Compared with Example 3, no EVA wax paste was added, and all other preparation steps were the same, resulting in a metal-like BIPV photovoltaic glass.

[0052] Comparative Example 2: Compared with Example 3, no N2 protection was used, and UV curing was carried out directly in air. All other preparation steps were the same, resulting in metal-like BIPV photovoltaic glass.

[0053] Comparative Example 3: Compared with Example 3, TMOS was not added in the preparation of silane sol, and all other preparation steps were the same, resulting in a metal-like BIPV photovoltaic glass.

[0054] Comparative Example 4: Compared with Example 3, TBOS was not added in the preparation of silane sol, and all other preparation steps were the same, resulting in a metal-like BIPV photovoltaic glass.

[0055] Comparative Example 5: Compared with Example 3, TEOS was not added, but all other preparation steps were the same, resulting in a metal-like BIPV photovoltaic glass.

[0056] Comparative Example 6: Compared with Example 3, no photoinitiator TPO was added, and all other preparation steps were the same, resulting in a metal-like BIPV photovoltaic glass.

[0057] Performance testing Metallic gloss test: Referring to standard GB / T 9754-2007, the surface gloss (GU) of the metallic BIPV photovoltaic glass in Examples 1-5 and Comparative Examples 1-6 was measured using a 60° gloss meter. The results are summarized in Table 1 below.

[0058] Visible light transmittance test: Referring to standard GB / T 2680-2021, the visible light transmittance (%) of the metal-like BIPV photovoltaic glass obtained in Examples 1-5 and Comparative Examples 1-6 was tested using an ultraviolet-visible-near-infrared spectrophotometer (380-1100nm). The results are summarized in Table 1 below.

[0059] Adhesion test: Referring to standard GB / T 9286-2021, the surfaces of the metal-like BIPV photovoltaic glass obtained in Examples 1-5 and Comparative Examples 1-6 were scratched with a cross-cutting knife and peeled off with 3M tape. The degree of peeling was rated from 0 to 5, with 0 being the best. The results are summarized in Table 1 below.

[0060] Table 1

[0061] Hydrophobicity and self-cleaning performance tests: For the metal-like BIPV photovoltaic glass obtained in Examples 1-5 and Comparative Examples 1-6, the hydrophobicity was tested using a contact angle meter according to standard GB / T 30447-2013 to measure the water contact angle (°); the self-cleaning performance was tested using a carbon black / dust mixture coating method according to standard GB / T 9780-2013 to measure the residual rate (%) after rinsing. The results are summarized in Table 2 below.

[0062] UV aging resistance test: Referring to standard GB / T 23987-2009, a UV-A (340nm) fluorescent UV lamp was used. The lamp was irradiated at 60℃ for 4 hours. Then the irradiation was stopped and the UV lamp was turned off. The lamp was kept at 50℃ and high humidity (95-100% RH) in the chamber for 4 hours. The above UV irradiation and high humidity condensation cycle was repeated for 500 hours. The visible light transmittance (%) before and after the test was tested and recorded. The transmittance reduction rate (%) was calculated and summarized as shown in Table 2.

[0063] Table 2

[0064] Based on the data in Tables 1 and 2 of the above test results, it can be seen that the metal-like BIPV photovoltaic glass obtained in Examples 1-5 of the present invention can maintain good light transmittance (above 80.5%) while also achieving excellent gloss (above 85 GU), and the surface has good hydrophobicity and aging resistance.

[0065] Compared to Example 3, Comparative Example 1 did not include EVA wax paste, and the pigment flakes were not protected. The pigments were prone to agglomeration, resulting in a significant decrease in gloss and light transmittance. It was unable to maintain high transmittance and did not achieve an excellent imitation metal plate effect. Comparative Example 2, due to the lack of nitrogen protection to inhibit oxygen polymerization in the bottom curing process, had incomplete surface curing, making the coating sticky and prone to aging, leading to a decrease in gloss, poor adhesion, and significantly reduced aging resistance. Comparative Examples 3, 4, and 5, due to the lack of TMOS, TBOS, and TEOS, respectively, could not form a gradient refractive index layer, resulting in decreased light transmittance, increased surface energy, a significant decrease in self-cleaning function, and weakened aging resistance. It can be seen that the top protective layer requires the synergistic effect of TMOS, TBOS, and TEOS, and none of them can be missing. Furthermore, Comparative Example 6 lacked TPO. During photocuring, the deep curing of the coating was insufficient, and the pigment flakes were not firmly fixed, resulting in varying degrees of decrease in gloss, adhesion, and aging resistance.

[0066] The above are preferred embodiments of the present invention. For those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing metal-plate-like BIPV photovoltaic glass, characterized in that: The preparation steps include the following: S1. Take butyl acetate, nano-cerium oxide and dispersant and grind and pre-disperse them. Add polyurethane diacrylate, TPGDA and photoinitiator and stir evenly. Add silver flake interference pigment and EVA wax paste, stir at low speed, adjust the spraying viscosity with butyl acetate, degas, filter and obtain the imitation metal interference coating. S2. After oxygen plasma treatment of the photovoltaic glass substrate, a metal interference-like coating is sprayed onto the substrate. After leveling, it is UV cured under N2 protection to form a metal interference-like coating on the surface of the photovoltaic glass substrate. S3. Mix isopropanol, TEOS, TMOS, and TBOS, add a mixture of hydrochloric acid and deionized water, stir at a constant temperature for hydrolysis, and then age in a sealed container to obtain silane sol. S4. Immerse the photovoltaic glass substrate with the underlying imitation metal interference coating into silane sol, pull it out, perform gradient curing, and cool it to obtain the imitation metal plate BIPV photovoltaic glass.

2. The method for preparing a metal-like BIPV photovoltaic glass according to claim 1, characterized in that: The photoinitiator is photoinitiator 184 and photoinitiator TPO; the dispersant is BYK-2151.

3. The method for preparing a metal-like BIPV photovoltaic glass according to claim 2, characterized in that: In step S1, 60% of the amount of butyl acetate, nano-cerium oxide, and BYK-2151 dispersant are added to a sand mill and pre-dispersed using 0.3mm zirconium beads in a circulating mill. The mixture is then transferred to a paint mixing tank, where polyurethane diacrylate, TPGDA, photoinitiator 184, and photoinitiator TPO are added at 200-300 rpm. The mixture is stirred until homogeneous, and the speed is reduced to 100-150 rpm. Silver-white flake interference pigment and EVA wax are slowly added and stirred at low speed. The remaining 40% of the amount of butyl acetate is used to adjust the spraying viscosity to 25°C. The mixture is then coated with a Forco 4 cup for 30-40 seconds, degassed under vacuum, and filtered through a 200-mesh filter to obtain a metallic interference coating.

4. The method for preparing a metal-like BIPV photovoltaic glass according to claim 2, characterized in that: The simulated metal interference coating comprises the following raw materials in parts by weight: 14-18 parts butyl acetate, 0.6-1 parts nano cerium oxide, 0.2-0.4 parts BYK-2151 dispersant, 40-45 parts polyurethane diacrylate, 30-35 parts TPGDA, 2-3 parts photoinitiator 184, 0.3-0.6 parts photoinitiator TPO, 2.0-2.5 parts silver-white flake interference pigment, and 0.3-0.5 parts EVA wax paste.

5. The method for preparing a metal-like BIPV photovoltaic glass according to claim 1, characterized in that: In step S2, after the embossed photovoltaic glass substrate is treated with oxygen plasma, it is then coated with two wet-on-wet sprays using an automatic spray gun with a 1.3mm nozzle and an atomizing pressure of 0.07MPa. The coating is flash-dried with a 3-second interval between coats. After leveling in a 50°C infrared oven for 5 minutes, it is cured under N2 protection using a UV curing machine with a radiation energy of 1200mJ / cm². 2 The irradiation time is about 10-15 seconds, thereby forming a bottom layer of metal-like interference coating on the surface of the photovoltaic glass substrate.

6. The method for preparing a metal-like BIPV photovoltaic glass according to claim 1, characterized in that: The oxygen plasma treatment process in step S2 is as follows: the embossed photovoltaic glass substrate is subjected to oxygen plasma treatment for 90 seconds under the conditions of power 300W and O2 flow rate 50sccm.

7. The method for preparing a metal-plate-like BIPV photovoltaic glass according to claim 6, characterized in that: In step S2, before the embossed photovoltaic glass substrate is subjected to oxygen plasma treatment, it is first ultrasonically cleaned at 50°C for 10 minutes with an alkaline cleaning agent of pH=11-12, rinsed with deionized water, and dried with hot air.

8. The method for preparing a metal-like BIPV photovoltaic glass according to claim 1, characterized in that: In step S3, isopropanol, TEOS, TMOS, and TBOS are mixed and stirred, and a mixture of 0.1 mol / L hydrochloric acid and deionized water is added dropwise. The mixture is stirred at a constant temperature of 40°C for 2 hours and then aged in a sealed container for 24 hours to obtain silane sol.

9. The method for preparing a metal-like BIPV photovoltaic glass according to claim 8, characterized in that: In the silane sol, the mass ratio of TEOS, TMOS and TBOS is (38-43):(11-14):(8-11).

10. The method for preparing a metal-like BIPV photovoltaic glass according to claim 1, characterized in that: In step S4, the photovoltaic glass substrate with the bottom layer of imitation metal interference coating is immersed in silane sol, held for 30 seconds, and then steadily pulled out and transferred to an oven for gradient curing. The temperature is increased to 180°C at a rate of 2°C / min, held for 60 minutes, and then cooled to room temperature to obtain imitation metal plate BIPV photovoltaic glass.

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