A dynamic omniphobic coating for photovoltaic panels and a method for its preparation

Abstract

This invention discloses a dynamic dual-repellent coating for photovoltaic panels and its preparation method. The dynamically dual-repellent self-cleaning coating disclosed herein comprises a multi-crosslinked polycarbonate-type polyurethane prepolymer grafted with organosilicon segments. Specifically, the multi-crosslinked polycarbonate-type polyurethane prepolymer containing organosilicon segments is obtained by multiple crosslinking of an organosilicon-grafted isocyanate crosslinking agent with various polyols. In the first step of the polymerization reaction, reactive polysiloxane segments are grafted onto the isocyanate crosslinking agent, and then in the second step of the multi-component crosslinking process, the polysiloxane segments are fully embedded in the coating, resulting in a dynamically dual-repellent self-cleaning coating.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically relating to a dynamic dual-hydrophobic coating for photovoltaic panels and its preparation method. Background Technology

[0002] Globally, there is a strong push to develop renewable energy sources such as wind power and photovoltaics. Solar energy is an inexhaustible and clean energy source, and solar photovoltaic modules have become the most important way to utilize solar energy. However, under various operating conditions, dust, rainwater, salt crystals, and vehicle exhaust pollutants on the glass panels of photovoltaic modules can significantly reduce the light transmittance of the panels, thereby reducing power generation. Furthermore, long-term outdoor moisture penetration can also affect the efficiency and lifespan of the modules. Research has confirmed that a self-cleaning coating can be applied to photovoltaic panels, utilizing the coating's repellency against water-based media to achieve passive self-cleaning and alleviate panel contamination problems. This method is low-cost, widely applicable, and highly efficient, and has attracted widespread attention.

[0003] In recent years, numerous researchers have made some progress in the field of self-cleaning photovoltaic panels:

[0004] Patent CN113088190B utilizes ammonia as a catalyst to hydrolyze and condense ethoxy and methoxy groups in a constant temperature and humidity environment using a fluorosiloxane precursor and a siloxane prepolymer, resulting in a fluorinated organopolysiloxane self-cleaning coating with strong hydrophobicity and good self-cleaning effect. This method is convenient, efficient, and has high applicability; however, the coating does not exhibit oleophobicity, and the fluorinated substances pose certain environmental hazards, both of which limit its application in the self-cleaning field of photovoltaic panels.

[0005] Patent CN114231177B describes a method for preparing nano-TiO2 / SiO2 composite powder via a silica-titanium dioxide composite sol and then performing vinyl modification. Subsequently, a fluorosilane-modified hydrogen-containing silicone oil is prepared through the polycondensation of hydroxyl silicone oil, hydrogen-containing silanes, and fluorinated silanes. Finally, the two are mixed with a platinum catalyst, coated, and cured to obtain a self-cleaning coating. The self-cleaning coating prepared by this strategy exhibits hydrophobic and oleophobic properties and demonstrates good degradation ability against contaminants. However, the photocatalytic material in this coating may reduce the durability of the polymer material, causing the coating to be unable to withstand long-term outdoor light damage.

[0006] In summary, the development and application of self-cleaning coatings for photovoltaic panels still face numerous challenges. Firstly, existing self-cleaning coatings for photovoltaic panels are mostly superhydrophobic or superhydrophilic surfaces, whose superwetting properties are difficult to maintain after long-term outdoor use, and their mechanical durability is weak, making them unable to withstand wind and sand damage. Furthermore, developed self-cleaning coatings typically only possess hydrophobicity, lacking repellency against oily pollutants such as automotive exhaust and industrial waste gases, thus failing to meet the needs of various application scenarios. Finally, the preparation and application processes of many self-cleaning coatings are complex, making them unsuitable for application on already operational photovoltaic modules, thus limiting their application. Therefore, there is an urgent need to develop a photovoltaic panel protective coating that combines self-cleaning, dual hydrophobicity, and ease of application. Summary of the Invention

[0007] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0008] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0009] Therefore, the object of the present invention is to overcome the shortcomings of the prior art and provide a dynamic dual-repellent coating for photovoltaic panels, said coating comprising, by weight parts,

[0010] 50-75 parts of multi-crosslinked polycarbonate-type polyurethane prepolymer containing organosilicon segments, 0.5-1.0 parts of catalyst, and 25-50 parts of coating diluent.

[0011] Another objective of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a dynamic dual-repellent coating for photovoltaic panels.

[0012] To solve the above-mentioned technical problems, the present invention provides the following technical solution: including,

[0013] The isocyanate crosslinking agent, catalyst, and reaction solvent are mixed and kept at 70-90°C in a nitrogen atmosphere. The mixture is stirred and refluxed for 20-40 minutes. The organosilicon modifier is then added, and the reaction is maintained for 2-6 hours to obtain the organosilicon modifier-grafted isocyanate crosslinking agent.

[0014] Polycarbonate diol oligomers, hyperbranched polyols, and small molecule polyols are dissolved in a reaction solvent, and then an isocyanate crosslinking agent grafted with an organosilicon modifier is added. The multiple crosslinking reaction continues for 1 to 3 hours to obtain a multi-crosslinked polycarbonate polyurethane prepolymer containing organosilicon segments with a solid content of 30% to 60%.

[0015] The multi-crosslinked polycarbonate polyurethane prepolymer containing organosilicon segments is mixed with the catalyst and coating diluent at a mass ratio of 50-100:0.5-1.0:25-50 and stirred evenly to obtain a coating solution for later use.

[0016] The photovoltaic glass panel is thoroughly cleaned with water, an acid-containing surfactant, and ethanol. After it is completely dry, the coating solution is evenly sprayed onto the photovoltaic glass panel and cured at room temperature or 50-120°C for 1-24 hours to obtain a dynamic double-hydrophobic coating.

[0017] The mass ratio of the isocyanate crosslinking agent, catalyst, and reaction solvent is 10–30: 0.1–0.5: 10–20.

[0018] The mass ratio of the organosilicon-modified isocyanate crosslinking agent, polycarbonate diol, hyperbranched polyol, and small molecule polyol is 25–35:40–60:6–12:3–8.

[0019] As a preferred embodiment of the method for preparing the dynamic dual-repellent coating for photovoltaic panels according to the present invention, the isocyanate crosslinking agent includes one or more of toluene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, terephthalic diisocyanate, dimethylbiphenyl diisocyanate, polymethylene polyphenyl isocyanate, hexamethylene diisocyanate, hexamethylene diisocyanate trimer, trimethylhexamethylene diisocyanate, or isoflurane diisocyanate.

[0020] In a preferred embodiment of the method for preparing the dynamic dual-hydrophobic coating for photovoltaic panels according to the present invention, the catalyst includes one or more of dibutyltin dilaurate and stannous octoate; the amount of the catalyst is 0.5-2 wt%.

[0021] As a preferred embodiment of the method for preparing a dynamic dual-hydrophobic coating for photovoltaic panels according to the present invention, the reaction solvent includes one or more of acetone, butanone, butyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, propylene glycol methyl ether, propylene glycol butyl ether, dipropylene glycol butyl ether, ethylene glycol methyl ether acetate, and propylene glycol methyl ether acetate.

[0022] In a preferred embodiment of the method for preparing the dynamic dual-hydrophobic coating for photovoltaic panels according to the present invention, the organosilicon modifier is a reactive polydimethylsiloxane containing one or more hydroxyl / amino groups at one end or in the side chain; the mass of the organosilicon modifier is 0.5% to 16% of the mass of the isocyanate crosslinking agent.

[0023] In a preferred embodiment of the method for preparing the dynamic dual-hydrophobic coating for photovoltaic panels according to the present invention, the molecular weight of the polycarbonate diol oligomer is 1000-2000 g / mol.

[0024] In a preferred embodiment of the method for preparing a dynamic dual-hydrophobic coating for photovoltaic panels according to the present invention, the hyperbranched polyol has a molecular weight of 500-1500 g / mol and a terminal hydroxyl number of 5-12.

[0025] As a preferred embodiment of the method for preparing the dynamic dual-hydrophobic coating for photovoltaic panels according to the present invention, the small molecule polyol is one or more of ethylene glycol, diethylene glycol, 1,2-propanediol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, and neopentyl glycol.

[0026] As a preferred embodiment of the method for preparing a dynamic dual-hydrophobic coating for photovoltaic panels according to the present invention, the coating diluent includes one or more of butyl acetate, propylene glycol methyl ether acetate, and N,N-dimethylacetamide.

[0027] Beneficial effects of this invention:

[0028] (1) Hyperbranched polyols and small molecule polyols together provide hydroxyl groups as crosslinking sites to ensure the formation of highly crosslinked coatings. This is conducive to the uniform grafting of organosilicon segments in the coating system and their enrichment on the coating surface after curing, achieving dynamic dual repellency and self-cleaning properties. This coating not only achieves dynamic sliding of water-based pollutants but also resists the adhesion of oil-based pollutants and passively cleans the dust on the coating surface during the sliding of water / oil droplets.

[0029] (2) The coating obtained by multiple cross-linking has excellent adhesion. The polycarbonate type polyurethane also has excellent humid heat stability, which works in synergy with low surface energy organosilicon segments to resist outdoor moisture intrusion and light damage.

[0030] (3) The dynamic dual-hydrophobic self-cleaning coating of the present invention can take into account both self-cleaning and durability, and is expected to be used for a long time to alleviate the problem of dust and other stains deposited on photovoltaic panels and increase their power generation. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0032] Figure 1This is a schematic diagram of a self-cleaning testing device, including (a) a dust deposition device, (b) a light transmittance tester and (c) a water dripping cleaning device;

[0033] Figure 2 This is the water contact angle result of the coating in Embodiment 1 of the present invention;

[0034] Figure 3 This is the light transmittance result of the coating in Example 1 of the present invention;

[0035] Figure 4 This is the water contact angle result of the coating in Comparative Example 2 of the present invention;

[0036] Figure 5 This is the light transmittance result of the coating in Comparative Example 2 of the present invention;

[0037] Figure 6 This is the water contact angle result of the coating in Comparative Example 3 of the present invention;

[0038] Figure 7 This is the light transmittance result of the coating in Comparative Example 3 of the present invention;

[0039] Figure 8 The transmittance of the samples was compared in the initial state, after dust deposition, and after self-cleaning. Detailed Implementation

[0040] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0041] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0042] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0043] Unless otherwise specified, all raw materials used in this invention are commercially available.

[0044] The materials obtained in the embodiments of the present invention were tested for their dual repellency and self-cleaning properties using the following method:

[0045] (1) Water / oil / organic solvent contact angle and sliding angle test

[0046] The static contact angle of 10 μL of deionized water and 10 μL of sunflower seed oil on the coating surface was measured using a contact angle meter. The dynamic sliding angle of 30 μL of deionized water and 15 μL of sunflower seed oil on the coating surface was measured using the tilting stage of the contact angle meter. The average value of the measured values ​​at 3 to 5 different locations was taken as the final static contact angle or dynamic sliding angle of the coating.

[0047] (2) Transmittance test

[0048] The transmittance of the coating on the float glass substrate was measured using a UV-Vis spectrophotometer in the wavelength range of 300–800 nm, with air as the blank background.

[0049] (3) Self-cleaning test

[0050] We designed and built a simulation device for dust deposition and self-cleaning processes. The device diagram is shown below. Figure 1 As shown, specifically, an electric powder sprayer was used to spray dust powder onto the surface of the coated sample, while maintaining a consistent dust deposition density. The dusty coated sample was then cleaned with the same mass of cleaning water at the same drip rate to simulate natural rainfall and self-cleaning processes. A portable visible light band average transmittance meter was used to measure the transmittance of the samples, and the transmittance recovery rate (%) was defined as follows:

[0051] Average transmittance recovery rate = (transmittance of the coated glass sample after cleaning - transmittance of the coated glass sample after dust contamination) / (transmittance of the initial coated glass sample - transmittance of the coated glass sample after dust contamination) × 100%.

[0052] Example 1

[0053] This embodiment provides a method for preparing a dynamic dual-hydrophobic coating, specifically as follows:

[0054] The formulation of the dynamic dual-hydrophobic coating is as follows: 72 parts of multi-crosslinked polycarbonate polyurethane prepolymer containing organosilicon segments, 0.6 parts of catalyst, and 36 parts of coating diluent.

[0055] (1) 2.0 g of isophorone diisocyanate, 0.03 g of dibutyltin dilaurate and 1.5 g of butanone were placed in a four-necked flask and stirred under a nitrogen atmosphere at 80 °C for 30 min under reflux. 0.03 g of mono-amino-terminated polydimethylsiloxane was added and reacted for 3 h to obtain an isocyanate crosslinking agent grafted with an organosilicon modifier;

[0056] (2) Dissolve 3.0g polycarbonate diol, 0.59g hyperbranched polyol, 0.25g neopentyl glycol and 2.5g N,N-dimethylacetamide completely under ultrasound, and add them evenly to the reaction system of step (1) using a micro-injection pump. Continue the reaction for 1 hour to obtain a multi-crosslinked polycarbonate polyurethane prepolymer containing organosilicon segments.

[0057] (3) Take 2.4g of multi-crosslinked polycarbonate polyurethane prepolymer containing organosilicon segments, 0.02g of catalyst and 1.2g of butyl acetate, mix them and stir evenly to obtain a coating solution for later use.

[0058] (4) Use water, citric acid cleaner and ethanol to thoroughly clean the ultra-white glass and let it dry completely; then spray the coating solution evenly on the glass and cure it at 120°C for 1 hour to obtain a dynamic double hydrophobic coating.

[0059] Figure 2 This is a diagram showing the water contact angle of the dynamic dual-hydrophobic coating obtained in this embodiment. Figure 3 The image shows the transmittance results of the dynamic dual-repellent coating obtained in this embodiment. It can be seen that... Figure 2 and Figure 3 The results show that by combining polydimethylsiloxane modification, hyperbranched polyols and small molecule polyols, a multi-crosslinked coating can achieve excellent dynamic dual-repellency properties and maintain high transparency in the visible light band. This property is of positive significance for the self-cleaning of photovoltaic modules and long-term stable power generation.

[0060] Example 2

[0061] The difference between this embodiment and Example 1 is that the mass of the single-amino-terminated polydimethylsiloxane is adjusted to 0.01g, while the rest of the preparation process is the same as in Example 1, to obtain a dynamic double hydrophobic coating.

[0062] Example 3

[0063] The difference between this embodiment and Example 1 is that the mass of the single-amino-terminated polydimethylsiloxane is adjusted to 0.32g, while the rest of the preparation process is the same as in Example 1, to obtain a dynamic double hydrophobic coating.

[0064] Example 4

[0065] The difference between this embodiment and Example 1 is that the reaction temperature is adjusted to 70°C, while the rest of the preparation process is the same as in Example 1, resulting in a dynamic double-hydrophobic coating.

[0066] Example 5

[0067] The difference between this embodiment and Example 1 is that the reaction temperature is adjusted to 90°C, while the rest of the preparation process is the same as in Example 1, resulting in a dynamic double-hydrophobic coating.

[0068] Example 6

[0069] The difference between this embodiment and Example 1 is that the mass of the hyperbranched polyol is adjusted to 0.3g, while the rest of the preparation process is the same as in Example 1, to obtain a dynamic double hydrophobic coating.

[0070] Example 7

[0071] The difference between this embodiment and Example 1 is that the mass of the hyperbranched polyol is adjusted to 0.76g, while the rest of the preparation process is the same as in Example 1, resulting in a dynamic double-hydrophobic coating.

[0072] The coatings prepared in the above embodiments were subjected to comprehensive performance tests, and the comparison results with those of Example 1 are shown in Table 1.

[0073] Table 1

[0074]

[0075] As shown in Table 1, adjusting the mass of polydimethylsiloxane and hyperbranched polyol significantly affects the performance of the dynamic bihydrophobic coating. This is because a small amount of polydimethylsiloxane segments cannot be sufficiently enriched on the coating surface, thus weakening the bihydrophobicity of the coating. While an excessive amount of polydimethylsiloxane imparts excellent bihydrophobicity to the coating, its segments undergo significant micro-phase separation within the coating system, resulting in a significant negative impact on the coating's transparency. For hyperbranched polyol, insufficient dosage leads to a low density of the multi-linked network in the coating, limiting its bihydrophobicity; while excessive dosage does not result in superior overall performance but instead increases the coating cost. Based on the results in the table, the optimal technical effect is achieved when the amounts of polydimethylsiloxane and hyperbranched polyol in this invention are 0.03 g and 0.59 g, respectively.

[0076] Comparative Example 1

[0077] This comparative example provides a conventional method for preparing a dual-hydrophobic coating, specifically as follows:

[0078] (1) Dissolve 4.0g of commercially available fluorocarbon resin (FEVE) and 0.5g of commercially available hexamethylene diisocyanate trimer in 4.0g of butyl acetate solvent, mix and stir evenly to obtain a coating solution for later use.

[0079] (2) Use water, acid-containing surfactant cleaning agent and ethanol to thoroughly clean the ultra-white glass and let it dry completely; then spray the coating solution evenly on the glass and cure it at 120°C for 1 hour to obtain a conventional double-hydrophobic coating.

[0080] Comparative Example 2

[0081] The difference between this comparative example and Example 1 is that polydimethylsiloxane is not added, but the rest of the preparation process is the same as in Example 1, resulting in a dynamic double hydrophobic coating.

[0082] Figure 4 This is the water contact angle result of the coating prepared in this comparative example; Figure 5 The results show the light transmittance of the coating prepared in this comparative example; it can be seen that although the coating has excellent transparency, it does not exhibit amphoteric properties. Figure 4 and Figure 5 This confirms that although the comparative example is a polycarbonate polyurethane coating that has achieved multiple crosslinking, its system does not contain low surface energy flexible polydimethylsiloxane segments, thus exhibiting hydrophilicity and failing to achieve dynamic sliding of water droplets and oil droplets.

[0083] Comparative Example 3

[0084] The difference between this comparative example and Example 1 is that no hyperbranched polyol is added, but the rest of the preparation process is the same as in Example 1, resulting in a dynamic dual-hydrophobic coating.

[0085] Figure 6 This is the water contact angle result of the coating in this comparative example; Figure 7 This is the light transmittance result of the coating in the comparative example; it can be seen that the coating maintains high transparency while exhibiting dihydrophobicity. Figure 6 and Figure 7 It was confirmed that when only polydimethylsiloxane was introduced as a modifier without using hyperbranched polyol as a crosslinking agent, the coating had a low degree of crosslinking, the grafting and migration of modifier segments were restricted, and the coating surface was prone to reconstruction, which was specifically reflected in unsatisfactory contact angle and sliding angle performance.

[0086] Figure 8 As can be seen in Example 1, after self-cleaning, the light transmittance of the coating essentially returned to its initial level, demonstrating excellent self-cleaning performance. In contrast, Comparative Example 2, which did not introduce polydimethylsiloxane, only recovered about 10% of its light transmittance. Although Comparative Example 3 introduced polydimethylsiloxane, the lack of a hyperbranched polyol crosslinking agent resulted in the coating not achieving multiple crosslinking, leading to insufficient self-cleaning performance and a recovery of only about 75% of its light transmittance.

[0087] Table 2

[0088]

[0089] As shown in Table 2, compared with the comparative examples, the antifouling coating examples prepared by the method of this disclosure combine hydrophobicity, oleophobicity, and self-cleaning properties. Importantly, when the antifouling coating of this disclosure is used as a protective layer for ultra-clear glass panels of photovoltaic cells, it can achieve highly efficient self-cleaning, and the average light transmittance recovery rate of the glass panel can reach over 99%.

[0090] Specifically, as shown in the table above, Comparative Example 2 did not use reactive polydimethylsiloxane material to graft the isocyanate crosslinking agent. Although a dense, multi-crosslinked coating was formed during curing, its surface lacked a low-surface-energy segment enrichment layer, thus exhibiting both hydrophilic and oleophilic properties and failing to achieve a self-cleaning effect. Comparative Example 3, in the prepolymerization process of isocyanate with organosilicon grafts and polyols, did not use a hyperbranched polyol crosslinking agent. The system contained only small-molecule diols. Based on this, the resulting coating had low crosslinking density, weak strength, and low organosilicon segment enrichment density, making it difficult to achieve excellent amphoteric properties, especially severely limiting droplet slip and self-cleaning performance. This is because the degree of crosslinking has a significant impact on the grafting efficiency of organosilicon segments in the coating system. Without a hyperbranched crosslinking agent, the system cannot fully achieve multi-crosslinking of isocyanate and hydroxyl groups. The coating polymer is mainly linearly polymerized rather than multi-dimensionally polymerized. Therefore, when the coating surface comes into contact with droplets, surface reconstruction easily occurs, making it difficult to achieve excellent droplet slip performance. In contrast, Example 1 prepared a polycarbonate-type polyurethane prepolymer containing organosilicon segments based on modified isocyanate crosslinking agent and hyperbranched polyol / small molecule polyol crosslinking agent, and obtained a dynamic dual-repellent coating with high crosslinking density and weak surface reconstruction effect. It can maintain dynamic dual-repellent properties for a long time and achieve long-term self-cleaning application, which has great potential for anti-fouling applications in photovoltaic panels.

[0091] The coating of this invention is obtained by crosslinking and curing a silicone-modified multi-crosslinked polycarbonate-type polyurethane prepolymer at room temperature. The silicone-modified multi-crosslinked polycarbonate-type polyurethane is composed of a silicone-modified isocyanate crosslinking agent, polycarbonate diol oligomer, hyperbranched polyol crosslinking agent, small molecule polyol crosslinking agent, catalyst, and solvent. The silicone-modified isocyanate crosslinking agent is obtained by a covalent reaction between a single-end reactive polydimethylsiloxane and a polyfunctional isocyanate; the multi-crosslinked polycarbonate-type polyurethane prepolymer is obtained by co-crosslinking a silicone-modified isocyanate with polycarbonate diol, hyperbranched polyol, and small molecule polyol. The silicone-modified isocyanate crosslinking agent can introduce low surface energy flexible chemical segments into the coating, giving the coating dynamic amphiphilic properties, achieving high contact angles and low sliding angles for both water and oil droplets, and enabling self-cleaning applications; various polyols provide the coating with abundant crosslinking and curing reaction sites, resulting in a coating with high crosslinking density, high adhesion, and durability. This invention aims to address the shortcomings of photovoltaic (PV) panels, such as limited hydrophobicity and weak self-cleaning properties. Currently reported self-cleaning coatings for PV panels typically fail to prevent contamination by oily media and suffer from reduced light transmittance and self-cleaning properties after prolonged use, potentially impacting the safe and stable operation of other PV module components. Therefore, this invention provides a dynamic dual-hydrophobic coating that balances transparency and self-cleaning performance for long-term, high-efficiency protection of PV panels.

[0092] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A dynamic dual-hydrophobic coating for photovoltaic panels, characterized in that: The coating, by parts by weight, comprises, 50-75 parts of multi-crosslinked polycarbonate-type polyurethane prepolymer containing organosilicon segments, 0.5-1.0 parts of catalyst, and 25-50 parts of coating thinner; The method for preparing the dynamic dual-repellent coating for photovoltaic panels, include, The isocyanate crosslinking agent, catalyst, and reaction solvent are mixed and kept at 70-90°C in a nitrogen atmosphere. The mixture is stirred and refluxed for 20-40 minutes. The organosilicon modifier is then added, and the reaction is maintained for 2-6 hours to obtain the organosilicon modifier-grafted isocyanate crosslinking agent. Polycarbonate diol oligomers, hyperbranched polyols, and small molecule polyols are dissolved in a reaction solvent, and then an isocyanate crosslinking agent grafted with an organosilicon modifier is added. The multiple crosslinking reaction continues for 1 to 3 hours to obtain a multi-crosslinked polycarbonate polyurethane prepolymer with a solid content of 30% to 60% containing organosilicon segments. The multi-crosslinked polycarbonate polyurethane prepolymer containing organosilicon segments is mixed with the catalyst and coating diluent at a mass ratio of 50~100:0.5~1.0:25~50 and stirred evenly to obtain a coating solution for later use. The photovoltaic glass panel is thoroughly cleaned with water, an acid-containing surfactant, and ethanol. After it is completely dry, the coating solution is evenly sprayed onto the photovoltaic glass panel and cured at room temperature or 50~120℃ for 1~24 h to obtain a dynamic double-hydrophobic coating. The mass ratio of the isocyanate crosslinking agent, catalyst, and reaction solvent is 10~30:0.1~0.5:10~20; The mass ratio of the organosilicon-modified isocyanate crosslinking agent, polycarbonate diol, hyperbranched polyol, and small molecule polyol is 25~35∶40~60∶6~12∶3~8; The organosilicon modifier is 0.5% to 16% of the mass of the isocyanate crosslinking agent; the organosilicon modifier is a reactive polydimethylsiloxane containing one or more hydroxyl / amino groups at one end or in the side chain.

2. The dynamic dual-hydrophobic coating for photovoltaic panels as described in claim 1, characterized in that: The isocyanate crosslinking agent includes one or more of toluene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, terephthalic diisocyanate, dimethylbiphenyl diisocyanate, polymethylene polyphenyl isocyanate, hexamethylene diisocyanate, hexamethylene diisocyanate trimer, trimethylhexamethylene diisocyanate, or isoflurane diisocyanate.

3. The dynamic dual-hydrophobic coating for photovoltaic panels as described in claim 1, characterized in that: The catalyst includes one or more of dibutyltin dilaurate and stannous octoate; the amount of the catalyst used is 0.5~2 wt%.

4. The dynamic dual-hydrophobic coating for photovoltaic panels as described in claim 1, characterized in that: The reaction solvent includes one or more of acetone, butanone, butyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, propylene glycol methyl ether, propylene glycol butyl ether, dipropylene glycol butyl ether, ethylene glycol methyl ether acetate, and propylene glycol methyl ether acetate.

5. The dynamic dual-hydrophobic coating for photovoltaic panels as described in claim 1, characterized in that: The molecular weight of the polycarbonate diol oligomer is 1000~2000 g / mol.

6. The dynamic dual-hydrophobic coating for photovoltaic panels as described in claim 1, characterized in that: The hyperbranched polyol has a molecular weight of 500-1500 g / mol and a terminal hydroxyl number of 5-12.

7. The dynamic dual-hydrophobic coating for photovoltaic panels as described in claim 1, characterized in that: The small molecule polyol is one or more of ethylene glycol, diethylene glycol, 1,2-propanediol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, and neopentyl glycol.

8. The dynamic dual-hydrophobic coating for photovoltaic panels as described in claim 1, characterized in that: The coating thinner includes one or more of butyl acetate, propylene glycol methyl ether acetate, and N,N-dimethylacetamide.

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