Composite coating, preparation method therefor, and use thereof

Abstract

A composite coating, a preparation method therefor, and the use thereof. The composite coating, in parts by mass, comprises the following components: 5-95 parts of silanol-modified silicon dioxide nanoscale microspheres, 20-50 parts of polymethylhydrosiloxane, 5-20 parts of boric acid, 30-60 parts of propylene glycol, and 1-10 parts of an acrylate.

Description

Composite coating and its preparation method and application

[0001] Related applications

[0002] This application claims priority to Chinese patent application No. 202311617410.6, filed on November 30, 2023, entitled “Composite coatings, preparation methods and applications thereof,” the entire text of which is hereby incorporated by reference. Technical Field

[0003] The present application relates to the field of coating technology, and in particular to a composite coating and a preparation method and application thereof. Background Art

[0004] Solar energy is a clean, safe, and reliable energy source, and the photovoltaic industry is currently experiencing rapid development. Photovoltaic modules include solar panels. When photovoltaic modules are operated outdoors for long periods of time, dust and other pollutants will accumulate on the glass surface of the modules, causing the modules to heat up and reducing their light transmittance and power. To avoid dust contamination, a super-hydrophilic coating is often formed on the surface of photovoltaic modules to form a water film structure to avoid dust contamination. However, the use of super-hydrophilic coatings cannot prevent moisture, especially seawater and acid rain, from corroding the aluminum frames of photovoltaic modules, seriously affecting the reliability of photovoltaic modules. To improve this situation, the current technical solution mainly involves forming a super-hydrophobic coating on the surface of photovoltaic modules. Summary of the Invention

[0005] In a first aspect, the present application provides a composite coating comprising the following components in parts by mass:

[0006] 5-95 parts of silanol-modified silica nanospheres, 20-50 parts of polymethyl hydrogen siloxane, 5-20 parts of boric acid, 30-60 parts of propylene glycol and 1-10 parts of acrylate.

[0007] In some embodiments, in the silanol-modified silica nanospheres, the mass ratio of silanol to silica nanospheres is (0.02-0.04):1.

[0008] In some embodiments, the silanol includes one or more of methylsilanetriol, tris(trimethylsilyl)silanol, triethylsilanol, and triisopropylsilanol.

[0009] In some embodiments, the silica nanospheres have a particle size of 200 nm to 300 nm.

[0010] In some embodiments, the acrylic acid ester includes one or more of butyl acrylate, methyl acrylate, ethyl acrylate, methyl 2-methacrylate, and ethyl 2-methacrylate.

[0011] In some embodiments, the composite coating further comprises one or more of a UV blocker, a heat stabilizer, an antioxidant, and a flame retardant.

[0012] In some embodiments, the UV protection agent includes one or more of benzotriazole, salicylates, benzophenones, acrylonitrile derivatives, triazine compounds, 3,5-di-tert-butyl-4-hydroxybenzyl monoethyl phosphate nickel, 2,2-thiobis(4-tert-octylphenol)nickel-n-butylamine and dibutyldithiocarbamate nickel.

[0013] In some embodiments, the heat stabilizer includes one or more of methyl tin mercaptan, tribasic lead salt, dibasic lead salt, zinc stearate, cadmium stearate, calcium stearate, zinc stearate, dibutyltin dilaurate, dibutyltin dimaleate, antimony mercaptides, and antimony carboxylates.

[0014] In some embodiments, the antioxidant includes one or more of antioxidant 1010 , antioxidant 168 , and antioxidant 300 .

[0015] In some embodiments, the flame retardant includes one or more of melamine, aluminum hydroxide, red phosphorus, antimony trioxide, and magnesium hydroxide.

[0016] In some embodiments, the mass fraction of the UV blocker is 0.1 to 2 parts, the mass fraction of the heat stabilizer is 0.1 to 6 parts, the mass fraction of the antioxidant is 0.1 to 3 parts, and the mass fraction of the flame retardant is 1 to 15 parts.

[0017] In a second aspect, the present application provides a method for preparing the composite coating as described in the first aspect, comprising the following steps:

[0018] The composite coating is prepared by mixing the silanol-modified silica nanospheres, the polymethyl hydrogen siloxane, the boric acid, the propylene glycol and the acrylate and heating them.

[0019] In some embodiments, the step of mixing the silanol-modified silica nanospheres, the polymethylhydrogensiloxane, the boric acid, the propylene glycol, and the acrylate comprises:

[0020] dissolving the boric acid and the polymethylhydrogensiloxane in the propylene glycol to form a mixed solution;

[0021] The silanol-modified silica nanospheres and the acrylic ester are mixed with the mixed solution.

[0022] In some embodiments, the silanol-modified silica nanospheres are prepared by a method comprising the following steps:

[0023] The silicon dioxide nanoparticles and silanol are dissolved in a solvent and dried to prepare the silanol-modified silicon dioxide nanoparticles.

[0024] In some embodiments, the heating conditions include:

[0025] First heat at 70℃~80℃ for 20min~40min; then heat to 100℃~110℃ and heat for 5min~20min.

[0026] In a third aspect, the present application provides a photovoltaic module, comprising a photovoltaic module body and a coating formed on the surface of the photovoltaic module body, wherein the coating is formed by the composite coating described in the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of this application or the technical solutions in related technologies, the following is a brief introduction to the drawings required for use in the specific implementation methods or related technical descriptions. Obviously, the drawings described below are some implementation methods of this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0028] FIG1 is a schematic structural diagram of a photovoltaic module provided in one embodiment of the present application. DETAILED DESCRIPTION

[0029] To facilitate understanding of the present application, the present application is described in more detail below. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of the present application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0031] the term:

[0032] As used herein, the term "and / or" includes any one of two or more of the listed items, as well as any and all combinations of the listed items, including any combination of any two, any more, or all of the listed items. For example, "A and / or B" includes A, B, and the combination of A and B.

[0033] In this document, unless otherwise specified, "one or more" means any one of the listed items or any combination of the listed items. Similarly, "one or more" and other expressions that mean "one or more" are also understood in the same way unless otherwise specified.

[0034] As used herein, the terms "further," "further," "particularly," "for example," "such as," "example," and "for instance" are used for descriptive purposes to indicate that the preceding and following technical solutions are related in terms of their coverage, but should not be construed as limiting the preceding technical solution or the scope of protection herein. As used herein, unless otherwise specified, "A (such as B)" means that B is a non-limiting example of A, and it should be understood that A is not limited to B.

[0035] As used herein, "optionally," "optional," and "optional" mean optional, that is, any one of the two parallel options of "with" or "without." If multiple "optional" items appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "optional" item is independent of the other. In this application, descriptions such as "optionally contain" and "optionally include" mean "containing or not containing." "Optional component X" means the presence or absence of component X, or the presence or absence of component X.

[0036] In this document, the terms "first," "second," "third," and "fourth," etc., are used for descriptive purposes only and should not be understood as indicating or implying relative importance or quantity, nor as implicitly indicating the importance or quantity of the technical features indicated. Furthermore, "first," "second," "third," and "fourth," etc., serve only as non-exhaustive enumeration and description and should not constitute a closed-ended limitation on quantity.

[0037] In this article, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0038] Herein, when referring to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​within the numerical interval is considered continuous and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when a numerical interval refers only to integers within the numerical interval, including the two endpoint integers of the numerical range, and each integer between the two endpoints, is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed herein should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows for broad inclusion of numerical interval types such as percentage intervals, ratio intervals, and ratio intervals.

[0039] The mass or weight of the relevant components mentioned in this application not only refers to the specific content of each component, but also represents the proportional relationship of the mass or weight between the components. Therefore, as long as the content of the relevant components in this application is proportionally enlarged or reduced, it is within the scope provided in this application.

[0040] Herein, the term "room temperature" or "normal temperature" generally refers to 4°C to 35°C, for example, 20°C ± 5°C. In some embodiments herein, "room temperature" or "normal temperature" refers to 10°C to 30°C. In some embodiments herein, "room temperature" or "normal temperature" refers to 20°C to 30°C.

[0041] In this document, if a method flow involves multiple steps, unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and they can be performed in an order other than the order described. Moreover, any step can include multiple sub-steps or multiple stages, and these sub-steps or stages do not necessarily need to be completed at the same time, but can be performed at different times, and their execution order does not necessarily need to be sequential, but can be performed in rotation, alternation, or simultaneously with other steps or parts of sub-steps or stages of other steps.

[0042] Currently, the material cost of preparing super-hydrophobic coatings is high, and their environmental tolerance and mechanical strength are poor. The embodiments of the present application provide a composite coating to improve the above problems and enhance the hydrophobicity, tolerance and wear resistance of photovoltaic modules.

[0043] The present application provides a composite coating comprising the following components in parts by mass:

[0044] 5-95 parts of silanol-modified silica nanospheres, 20-50 parts of polymethyl hydrogen siloxane, 5-20 parts of boric acid, 30-60 parts of propylene glycol and 1-10 parts of acrylate.

[0045] The composite coating provided by the embodiment of the present application adopts silicon dioxide nano-microspheres as raw materials. The surface energy of silicon dioxide is low, which can play a good hydrophobicity. At the same time, the nano-scale silicon dioxide microspheres can be arranged irregularly in the process of forming the coating, providing the coating with a microscopic surface roughness structure, so that a larger gas-liquid contact surface can be formed when the coating contacts the water droplets, and a larger contact angle can be formed, so that the water droplets appear to be "lifted" on the coating surface, thereby improving the hydrophobicity of the coating. Further, the silanol in the coating can react with silicon dioxide, further reducing the surface energy of the formed coating and improving its hydrophobicity. Acrylate can improve the processing fluidity of the coating and give it low hygroscopicity; it can also ensure the weather resistance and wear resistance of the formed coating, and give it excellent optical properties, improving its light transmittance.

[0046] Furthermore, the complexation of boric acid and propylene glycol produces triangular boron sites, which can further bind to hydroxyl groups in polymethylhydrogensiloxane to form a three-dimensional network. The polymethylhydrogensiloxane serves as a backbone material in this three-dimensional network, providing low surface energy and further enhancing the hydrophobicity of the resulting coating. The BO bonds at the boron sites can undergo dynamic exchange, allowing for self-repair when the three-dimensional network is disrupted, thereby maintaining its existence.

[0047] In summary, the composite coating provided by the embodiment of the present application can form a coating with excellent hydrophobicity, wear resistance and blister resistance. Therefore, after the composite coating forms a coating on the surface of the photovoltaic module body, it can make the water droplets on the surface of the photovoltaic module body fall off quickly, and while falling off, it can take away the dust and pollutants on the coating surface, thereby achieving the self-cleaning of the photovoltaic module, while being able to improve the light transmittance of the glass structure in the photovoltaic module, and also avoid the problem of dust and other pollutants causing heat to the photovoltaic module, thereby improving its efficiency and reliability. In addition, in seawater or acid rain environments, the excellent hydrophobicity can also avoid the metal structure in the photovoltaic module from being corroded, further improving its long-term reliability. Moreover, the composite coating formula is simple and low in cost.

[0048] In some embodiments, the mass ratio of silanol to silica nanospheres in the silanol-modified silica nanospheres is (0.02-0.04):1. By regulating the mass ratio of silanol to silica nanospheres within the above range, the silica nanospheres can be further fully modified and their surface energy can be reduced without causing silanol residue, thereby avoiding adverse effects on the mechanical and thermal properties of the formed coating.

[0049] In some embodiments, the particle size of the silica nanospheres is 200 nm to 300 nm, for example, 210 nm, 220 nm, 230 nm, 240 nm, 250 nm, 260 nm, 270 nm, 280 nm, or 290 nm. By regulating the particle size of the silica nanospheres within this range, the surface roughness of the coating formed by the composite coating can be further improved while maximally maintaining the mechanical properties of the coating.

[0050] It should be noted that the particle size of the silica nanospheres refers to the average particle size of the silica nanospheres.

[0051] In some embodiments, the silanol includes one or more of methylsilanetriol, tris(trimethylsilyl)silanol, triethylsilanol, and triisopropylsilanol.

[0052] In some embodiments, the acrylate includes one or more of butyl acrylate, methyl acrylate, ethyl acrylate, methyl 2-methacrylate, and ethyl 2-methacrylate.

[0053] It is understood that in order to give the coating more properties, additives commonly used in the field of coating preparation can also be added to the composite coating. For example, the additives can include one or more of UV inhibitors, heat stabilizers, antioxidants and flame retardants.

[0054] In some embodiments, the UV blocking agent includes one or more of benzotriazole, salicylates, benzophenones, acrylonitrile derivatives, triazine compounds, 3,5-di-tert-butyl-4-hydroxybenzyl monoethyl phosphate nickel, 2,2-thiobis(4-tert-octylphenol)nickel-n-butylamine and dibutyldithiocarbamate nickel.

[0055] In some embodiments, the heat stabilizer includes one or more of methyl tin mercaptide, tribasic lead salt, dibasic lead salt, zinc stearate, cadmium stearate, calcium stearate, zinc stearate, dibutyltin dilaurate, dibutyltin dimaleate, antimony mercaptides, and antimony carboxylates.

[0056] In some embodiments, the antioxidant includes one or more of antioxidant 1010 , antioxidant 168 , and antioxidant 300 .

[0057] In some embodiments, the flame retardant includes one or more of melamine, aluminum hydroxide, red phosphorus, antimony trioxide, and magnesium hydroxide.

[0058] Furthermore, in the composite coating, the addition amount of the UV inhibitor can be 0.1 to 2 parts by mass, the addition amount of the heat stabilizer can be 0.1 to 6 parts by mass, the addition amount of the antioxidant can be 0.1 to 3 parts by mass, and the addition amount of the flame retardant can be 1 to 15 parts by mass.

[0059] In a second aspect, an embodiment of the present application provides a method for preparing the composite coating as described in the first aspect, comprising the following steps:

[0060] The composite coating is prepared by mixing and heating silanol-modified silica nanospheres, polymethylhydrogensiloxane, boric acid, propylene glycol and acrylate.

[0061] In some embodiments, the step of mixing silanol-modified silica nanospheres, polymethylhydrogen siloxane, boric acid, propylene glycol, and acrylate comprises:

[0062] dissolving boric acid and polymethylhydrogensiloxane in propylene glycol and performing ultrasonic treatment to form a mixed solution;

[0063] The composite coating is prepared by mixing silanol-modified silicon dioxide nanoparticles and acrylic ester with the mixed liquid and heating the mixture.

[0064] In some embodiments, the ultrasonic treatment time is 30 min to 60 min.

[0065] In some embodiments, the heating conditions include: first heating at 70°C to 80°C for 20 min to 40 min; then heating to 100°C to 110°C for 5 min to 20 min.

[0066] In some embodiments, the silanol-modified silica nanospheres are prepared by a method comprising the following steps:

[0067] The silicon dioxide nanoparticles and silanol are dissolved in a solvent and dried to prepare the silicon dioxide nanoparticles modified with silanol.

[0068] In some embodiments, the solvent is water, for example, ultrapure water.

[0069] It is understood that the drying may specifically be heating drying, and the drying conditions are not limited as long as the solvent can be removed to form a dry powder.

[0070] In a third aspect, an embodiment of the present application provides a photovoltaic module 10 , comprising a photovoltaic module body 14 and a coating 12 formed on a surface of the photovoltaic module body 14 , wherein the coating is formed of the composite coating described in the first aspect.

[0071] It is understood that the method for forming the composite slurry into a coating layer can be any method known in the field of coating preparation. For example, a coating method can be used to form a coating layer on the surface of the photovoltaic module body. Specifically, a dipping method can be used.

[0072] It can be understood that the coating can be formed on the entire surface of the photovoltaic module body, and can also be formed on the surface of the glass structure or metal structure in the photovoltaic module.

[0073] In some embodiments, the coating has a thickness of 8 nm to 10 nm.

[0074] The following is a further detailed description of the embodiments of the present application in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present application only and are not intended to limit the scope of the present application. For experimental methods in the following examples where specific conditions are not specified, reference should be made to the guidance provided in this application. Alternatively, the experimental manuals or conventional conditions in this field may be used, or the conditions recommended by the manufacturer may be used, or experimental methods known in the art may be used.

[0075] In the following specific examples, the measured parameters of raw material components may have slight deviations within the range of weighing accuracy unless otherwise specified. For temperature and time parameters, acceptable deviations due to instrument testing accuracy or operational accuracy are allowed. "Room temperature" refers to 25°C.

[0076] Example 1

[0077] In this embodiment, the content of each component is calculated in parts by mass.

[0078] 1) dissolving 85 parts of 300 nm silica nanospheres and 2.55 parts of methylsilanetriol in 0.5 L of ultrapure water, and after the mixture is fully dissolved, placing the mixture in a drying chamber to completely evaporate the water, thereby preparing methylsilanetriol-modified silica nanospheres;

[0079] 2) 30 parts of polymethylhydrogensiloxane and 10 parts of boric acid were dissolved in 50 parts of propylene glycol to form a mixed solution. The mixed solution was ultrasonically treated at room temperature for 30 minutes. Then, the methylsilanetriol-modified silica microspheres prepared in step 1) and 8 parts of butyl acrylate were added. The temperature was then raised to 75°C and stirred for 30 minutes. The temperature was then raised to 105°C and maintained for 10 minutes to prepare a slurry.

[0080] 3) The slurry prepared in step 2) was applied to a glass surface by a dip coating process, and then vacuum treated at 95° C. for 10 h to form a super-hydrophobic coating with a thickness of 10 nm on the glass surface.

[0081] Example 2

[0082] In this embodiment, the content of each component is calculated by weight. The preparation method of Example 2 is basically the same as the preparation method of Example 1, except that the content of silica nanospheres and methylsilanetriol is different. The specific steps are as follows:

[0083] 1) dissolving 45 parts of 200 nm silica nanospheres and 1.35 parts of methylsilanetriol in 0.5 L of ultrapure water, and after the mixture is fully dissolved, placing the mixture in a drying chamber to completely evaporate the water, thereby preparing methylsilanetriol-modified silica nanospheres;

[0084] 2) 30 parts of polymethylhydrogensiloxane and 10 parts of boric acid were dissolved in 50 parts of propylene glycol to form a mixed solution. The mixed solution was ultrasonically treated at room temperature for 30 minutes, and then the methylsilanetriol-modified silica microspheres prepared in step 1) and 8 parts of butyl acrylate were added. The temperature was then raised to 75°C and stirred for 30 minutes. The temperature was then raised to 105°C and maintained for 10 minutes to prepare a slurry.

[0085] 3) The slurry prepared in step 2) was applied to a glass surface by a dip coating process, and then vacuum treated at 95° C. for 10 h to form a super-hydrophobic coating with a thickness of 10 nm on the glass surface.

[0086] Example 3

[0087] In this embodiment, the content of each component is calculated by weight. The preparation method of Example 3 is basically the same as the preparation method of Example 1, except that the content of polymethylhydrogensiloxane is different. The specific steps are as follows:

[0088] 1) dissolving 85 parts of 250 nm silica nanospheres and 2.55 parts of methylsilanetriol in 0.5 L of ultrapure water, and after the mixture is fully dissolved, placing the mixture in a drying chamber to completely evaporate the water, thereby preparing methylsilanetriol-modified silica nanospheres;

[0089] 2) Dissolve 40 parts of polymethylhydrogensiloxane and 10 parts of boric acid in 50 parts of propylene glycol to form a mixed solution. After ultrasonically treating the mixed solution at room temperature for 30 minutes, add the methylsilanetriol-modified silica microspheres prepared in step 1) and 8 parts of butyl acrylate. The temperature is then raised to 75°C and stirred for 30 minutes. The temperature is then raised to 105°C and maintained for 10 minutes to prepare a slurry.

[0090] 3) The slurry prepared in step 2) was applied to a glass surface by a dip coating process, and then vacuum treated at 95° C. for 10 h to form a super-hydrophobic coating with a thickness of 8 nm on the glass surface.

[0091] Example 4

[0092] The preparation method of this embodiment is basically the same as that of Example 1, except that the particle size of the silicon dioxide nanospheres is 150 nm.

[0093] Example 5

[0094] The preparation method of this embodiment is basically the same as that of Example 1, except that the particle size of the silicon dioxide nanospheres is 350 nm.

[0095] Example 6

[0096] The preparation method of this embodiment is basically the same as that of embodiment 1, except that the amounts of silicon dioxide nanospheres and methylsilanetriol are 85 parts and 1.275 parts, respectively.

[0097] Example 7

[0098] The preparation method of this embodiment is basically the same as that of embodiment 1, except that the amounts of silicon dioxide nanospheres and methylsilanetriol are 85 parts and 3.825 parts, respectively.

[0099] Example 8

[0100] The preparation method of this embodiment is substantially the same as that of embodiment 1, except that: 1 part by weight of antioxidant 1010, 0.5 parts by weight of benzotriazole, 1 part by weight of methyl tin mercaptan, and 8 parts by weight of melamine are further included.

[0101] Comparative Example 1

[0102] In this comparative example, the content of each component is calculated by weight. The preparation method of comparative example 1 is basically the same as that of Example 3, except that methylsilanetriol is not used to modify the silica nanospheres. The specific steps are as follows:

[0103] 1) 85 parts of 250 nm silica nanospheres, 2.55 parts of methylsilanetriol, 40 parts of polymethylhydrogensiloxane, and 10 parts of boric acid were dissolved in 50 parts of propylene glycol to form a mixed solution. The mixed solution was ultrasonically treated at room temperature for 30 minutes, and then 8 parts of butyl acrylate was added. The temperature was then raised to 75°C and stirred for 30 minutes. The temperature was then raised to 105°C and maintained for 10 minutes to prepare a slurry.

[0104] 2) The slurry prepared in step 1) was applied to a glass surface by a dip coating process, and then vacuum treated at 95° C. for 10 h to form a coating with a thickness of 8 nm on the glass surface.

[0105] Comparative Example 2

[0106] In this comparative example, the content of each component is calculated by weight. The preparation method of comparative example 2 is basically the same as that of example 3, except that micron-sized silica is used instead of silica nanospheres. The specific steps are as follows:

[0107] 1) dissolving 85 parts of micron-sized silica with a diameter of 200 μm and 2.55 parts of methylsilanetriol in 0.5 L of ultrapure water, and after the silica is fully dissolved, placing the silica in a drying chamber to completely evaporate the water, thereby obtaining micron-sized silica modified with methylsilanetriol;

[0108] 2) 40 parts of polymethylhydrogensiloxane and 10 parts of boric acid were dissolved in 50 parts of propylene glycol to form a mixed solution. The mixed solution was ultrasonically treated at room temperature for 30 minutes. Then, the methylsilanetriol-modified micron-sized silica prepared in step 1) and 8 parts of butyl acrylate were added. The temperature was then raised to 75°C and stirred for 30 minutes. The temperature was then raised to 105°C and maintained for 10 minutes to prepare a slurry.

[0109] 3) The slurry prepared in step 2) was applied to a glass surface by a dip coating process, and then vacuum treated at 95° C. for 10 h to form a coating with a thickness of 8 nm on the glass surface.

[0110] Comparative Example 3

[0111] In this comparative example, the content of each component is calculated by weight. The preparation method of comparative example 3 is basically the same as that of embodiment 3, except that methylsilanetriol is not added. The specific steps are as follows:

[0112] 1) 85 parts of 250 nm silica nanospheres, 40 parts of polymethylhydrogensiloxane, and 10 parts of boric acid were dissolved in 50 parts of propylene glycol to form a mixed solution. The mixed solution was ultrasonically treated at room temperature for 30 minutes, and then 8 parts of butyl acrylate was added. The temperature was then raised to 75°C and stirred for 30 minutes. The temperature was then raised to 105°C and maintained for 10 minutes to prepare a slurry.

[0113] 2) The slurry prepared in step 1) was applied to a glass surface by a dip coating process, and then vacuum treated at 95° C. for 10 h to form a coating with a thickness of 8 nm on the glass surface.

[0114] Comparative Example 4

[0115] In this comparative example, the content of each component is calculated by weight. The preparation method of comparative example 4 is basically the same as that of example 3, except that silica nanospheres and methylsilanetriol are not added. The specific steps are as follows:

[0116] 1) 40 parts of polymethylhydrogensiloxane and 10 parts of boric acid were dissolved in 50 parts of propylene glycol to form a mixed solution. The mixed solution was ultrasonically treated at room temperature for 30 minutes, and then 8 parts of butyl acrylate was added. The temperature was then raised to 75°C and stirred for 30 minutes. The temperature was then raised to 105°C and maintained for 10 minutes to prepare a slurry.

[0117] 2) The slurry prepared in step 1) was applied to a glass surface by a dip coating process, and then vacuum treated at 95° C. for 10 h to form a coating with a thickness of 8 nm on the glass surface.

[0118] Comparative Example 5

[0119] In this comparative example, the content of each component is calculated by weight. The preparation method of comparative example 5 is basically the same as that of example 3, except that polymethylhydrogensiloxane and boric acid are not added. The specific steps are as follows:

[0120] 1) dissolving 85 parts of 250 nm silica nanospheres and 2.55 parts of methylsilanetriol in 0.5 L of ultrapure water, and after the mixture is fully dissolved, placing the mixture in a drying chamber to completely evaporate the water, thereby preparing methylsilanetriol-modified silica nanospheres;

[0121] 2) The methylsilanetriol-modified silica microspheres prepared in step 1) and 8 parts of butyl acrylate were dissolved in 50 parts of propylene glycol to form a mixed solution. The mixed solution was ultrasonically treated at room temperature for 30 minutes. The temperature was then raised to 75°C and stirred for 30 minutes. The temperature was then raised to 105°C and maintained for 10 minutes to prepare a slurry.

[0122] 3) The slurry prepared in step 2) was applied to a glass surface by a dip coating process, and then vacuum treated at 95° C. for 10 h to form a coating with a thickness of 8 nm on the glass surface.

[0123] The raw materials and other process parameters in the preparation methods of Examples 1 to 3 and Comparative Examples 1 to 5 are shown in Table 1:

[0124] Table 1

[0125] The coatings prepared in Examples 1 to 8 and Comparative Examples 1 to 5 were subjected to relevant performance tests, and the test results are shown in Table 2 below.

[0126] Among them, the test conditions or test standards for each performance test item are as follows:

[0127] 1) Contact angle: tested according to ISO 8296;

[0128] 2) Roll angle: tested according to ISO 8296;

[0129] 3) Water resistance: The coatings prepared in each example and comparative example were immersed in water for 12 hours, taken out, dried, and then tested for contact angle according to ISO 8296.

[0130] 4) Abrasion Resistance: A coated glass was placed at a 45° angle to the horizontal. 2 kg of sand was dropped from a height of 2 m above the surface to abrade the coating. After the sand had fallen, the abraded coating was removed and its contact angle was measured according to ISO 8296.

[0131] Table 2

[0132] As can be seen from Table 2 above, from the test results of Examples 1 to 3, the greater the mass ratio of silica nanospheres to polymethylhydrogensiloxane, the better the hydrophobicity of the prepared coating; from the test results of Example 1 and Examples 4 and 5, it can be seen that the particle size of the silica nanospheres will significantly affect the hydrophobicity of the prepared coating, and regulating the particle size of the silica nanospheres within a reasonable range can improve the surface roughness of the coating and improve its hydrophobicity; from the test results of Examples 1 and Examples 6 and 7, it can be seen that the mass ratio of silica nanospheres to methylsilanetriol is within the range provided in this application, which can fully modify the silica nanospheres by silanol, thereby reducing the surface energy of the formed coating and improving its hydrophobicity without residual silanol; from the test results of Example 3 and Comparative Example 1,3 and 4 test results show that after methylsilanetriol is modified to silica nanospheres, by the reaction of methylsilanetriol and silica, the surface energy of the coating can be reduced, so that the hydrophobicity of the coating can be significantly improved; By the test results of Example 3 and Comparative Example 2, compared to the silica of other levels (micrometer level), silica nanospheres with irregular arrangement structure are used, the roughness of the coating surface can be improved, the contact area of ​​the gas phase and the liquid phase is increased, so that the hydrophobicity of the coating can be significantly improved; By the test results of Example 3 and Comparative Example 5, after adding boric acid and polymethyl hydrogen siloxane, boric acid can be complexed with propylene glycol to form a triangular boron site, and the boron site can further be combined with the hydroxyl group in polymethyl hydrogen siloxane to form a three-dimensional network structure. The polymethyl hydrogen siloxane in the three-dimensional network structure serves as a skeleton, can provide low surface energy for the coating, and improve the hydrophobicity of the coating; and the BO bond in the boron site can realize dynamic exchange, and when the three-dimensional network structure is destroyed, self-repair can be carried out. The presence of a three-dimensional network structure can improve the hydrophobicity of the coating and also enhance the coating's tolerance to the environment.

[0133] In summary, the coating provided in this application has excellent hydrophobicity, thereby preventing corrosion of photovoltaic modules and improving their long-term reliability. Furthermore, the coating can also make photovoltaic modules self-cleaning and improve their light transmittance.

[0134] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0135] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A composite coating, characterized in that: According to the weight percentage, it includes the following components: 5-95 parts of silanol-modified silicon dioxide nanospheres, 20-50 parts of polymethyl hydrogen siloxane, 5-20 parts of boric acid, 30-60 parts of propylene glycol and 1-10 parts of acrylate.

2. The composite coating according to claim 1, characterized in that: In the silanol-modified silica nanospheres, the mass ratio of silanol to silica nanospheres is (0.02-0.04):

1.

3. The composite coating according to claim 2, characterized in that: The silanol includes one or more of methylsilanetriol, tris(trimethylsilyl)silanol, triethylsilanol and triisopropylsilanol.

4. The composite coating according to any one of claims 1 to 3, characterized in that: The particle size of the silicon dioxide nanospheres is 200nm to 300nm.

5. The composite coating according to any one of claims 1 to 4, characterized in that: The acrylic acid ester includes one or more of butyl acrylate, methyl acrylate, ethyl acrylate, 2-methyl methacrylate and 2-ethyl methacrylate.

6. The composite coating according to any one of claims 1 to 5, characterized in that: It also includes one or more of an anti-ultraviolet agent, a heat stabilizer, an antioxidant and a flame retardant.

7. The composite coating according to claim 6, characterized in that: The anti-ultraviolet agent includes one or more of benzotriazole, salicylates, benzophenones, acrylonitrile derivatives, triazine compounds, 3,5-di-tert-butyl-4-hydroxybenzyl phosphate monoethyl nickel, 2,2-thiobis(4-tert-octylphenol)nickel-n-butylamine and dibutyldithiocarbamate nickel.

8. The composite coating according to claim 6 or 7, characterized in that: The heat stabilizer includes one or more of methyl tin mercaptan, tribasic lead salt, dibasic lead salt, zinc stearate, cadmium stearate, calcium stearate, zinc stearate, dibutyltin dilaurate, dibutyltin dimaleate, antimony mercaptides and antimony carboxylates.

9. The composite coating according to any one of claims 6 to 8, characterized in that: The antioxidant includes one or more of antioxidant 1010 , antioxidant 168 , and antioxidant 300 .

10. The composite coating according to any one of claims 6 to 9, characterized in that: The flame retardant includes one or more of melamine, aluminum hydroxide, red phosphorus, antimony trioxide and magnesium hydroxide.

11. The composite coating according to any one of claims 6 to 10, characterized in that: The mass fraction of the anti-ultraviolet agent is 0.1 to 2 parts, the mass fraction of the heat stabilizer is 0.1 to 6 parts, the mass fraction of the antioxidant is 0.1 to 3 parts, and the mass fraction of the flame retardant is 1 to 15 parts.

12. A method for preparing a composite coating according to any one of claims 1 to 11, characterized in that: The following steps are involved: The silanol-modified silica nanospheres, the polymethyl hydrogen siloxane, the boric acid, the propylene glycol and the acrylate are mixed and heated to prepare the composite coating.

13. The preparation method according to claim 12, characterized in that: The step of mixing the silanol-modified silica nanospheres, the polymethylhydrogensiloxane, the boric acid, the propylene glycol and the acrylate comprises: dissolving the boric acid and the polymethylhydrogensiloxane in the propylene glycol to form a mixed solution; The silanol-modified silica nanospheres and the acrylic ester are mixed with the mixed solution.

14. The preparation method according to claim 12 or 13, characterized in that: The silanol-modified silica nanospheres are prepared by a method comprising the following steps: The silicon dioxide nano-microspheres and silanol are dissolved in a solvent and dried to prepare the silanol-modified silicon dioxide nano-microspheres.

15. The preparation method according to any one of claims 12 to 14, characterized in that: The heating conditions include: First heat at 70℃~80℃ for 20min~40min; then heat to 100℃~110℃ and heat for 5min~20min.

16. A photovoltaic module, characterized in that: It comprises a photovoltaic component body and a coating formed on the surface of the photovoltaic component body, wherein the coating is formed by the composite coating according to any one of claims 1 to 11.

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