Ink for photovoltaic module and method of preparation

Abstract

The application relates to the technical field of new inks, and particularly discloses an ink for photovoltaic modules and a preparation method thereof. The ink comprises the following raw materials: a self-repairing resin base, a synergistic functional filler system, a curing initiator, a diluent and an additive; the preparation method comprises the following steps: S1, dissolving a network prepolymer and a network precursor in a diluent, stirring until uniform under light-proof conditions, and obtaining a resin base solution; S2, adding surface-hydroxylized hexagonal boron nitride nanosheets and chloride ion responsive organic-inorganic hybrid layered fillers into the diluent in proportion, ultrasonic dispersion to form a filler pre-dispersed slurry; S3, adding the filler pre-dispersed slurry into the resin base solution under stirring, high-speed dispersion under light-proof conditions, then adding the curing initiator and the additive, and vacuum degassing, so as to obtain the ink for photovoltaic modules. The ink can be used for the protection of a backboard of a photovoltaic module on the sea, and has the advantages of active self-repairing and wet-state adhesion maintenance.

Description

Technical Field

[0001] This application relates to the field of novel ink technology, and more specifically, to an ink for photovoltaic modules and a method for its preparation. Background Technology

[0002] Photovoltaic modules, operating outdoors for extended periods, must withstand multiple conditions including ultraviolet radiation, humid heat cycling, diurnal temperature variations, and chloride ion corrosion in coastal saline-alkali areas. Their backsheets, busbars, solder strips, and edge sealing areas typically rely on organic protective inks or coatings to provide barrier and insulation functions. Currently, mainstream protective inks for photovoltaic modules are made from fluoropolymers, modified acrylates, polyurethanes, or epoxy resins as base materials, combined with traditional sheet / spherical fillers such as mica, talc, and titanium dioxide. Thanks to the hydrophobicity of the resin itself and the physical barrier effect of the fillers, they can effectively delay the penetration of water vapor, oxygen, and corrosive ions while maintaining the integrity of the coating. They have the advantages of mature technology, controllable cost, and compatibility with existing coating lines.

[0003] The inks in question develop microcracks due to thermal stress, hail impact, or long-term aging. The coating itself lacks self-repair capabilities, and the cracks become a rapid channel for impurities to reach the substrate, leading to corrosion that extends from the crack tips. Simultaneously, the cohesive strength and interfacial adhesion strength of acrylate or epoxy resins decrease in humid and hot environments. Furthermore, biomimetic wet adhesion groups such as catechol are not introduced into the resin side chains, resulting in a significant deterioration in the cross-cut adhesion of the backplate or weld strip after a period of service in high-humidity and high-salt coastal environments. Summary of the Invention

[0004] To address the issues of microcrack formation and susceptibility to corrosion caused by the presence of acrylate or epoxy resins in related inks, this application provides an ink for photovoltaic modules and a method for its preparation.

[0005] In a first aspect, this application provides an ink for photovoltaic modules, employing the following technical solution: An ink for photovoltaic modules comprises the following raw materials in parts by weight: a self-healing resin base: 45-70 parts; a synergistic functional filler system: 15-30 parts; a curing initiator: 1-5 parts; a diluent: 10-30 parts; and an additive: 0.5-3 parts; wherein the self-healing resin base is an interpenetrating network prepolymer system, comprising a network prepolymer and a network precursor; the network prepolymer is an acrylate copolymer containing catechol side groups, obtained by free radical polymerization of a monomer mixture comprising dopamine methacrylamide, butyl methacrylate, and hydroxyethyl acrylate; The network precursor is a cross-linked prepolymer containing dynamic borate ester bonds, prepared by dehydration condensation reaction of terminal diol oligomers and compounds containing phenylboronic acid groups, and retaining unreacted active diol end groups; the synergistic functional filler system is composed of surface-hydroxylated hexagonal boron nitride nanosheets and chloride ion-responsive organic-inorganic hybrid layered fillers at a mass ratio of 1:0.3 to 1:1.5; the chloride ion-responsive organic-inorganic hybrid layered filler uses layered bimetallic hydroxide as a matrix, and repair agent monomers are intercalated in its interlayer domains by ion exchange, the repair agent monomers carrying both catechol groups and diol groups; the additives are leveling agents or defoamers.

[0006] By adopting the above technical solutions, the ink of this application constructs an organic combination of an interpenetrating network prepolymer system and a synergistic functional filler system. The network prepolymer in the interpenetrating network prepolymer system, by introducing catechol side groups, endows the coating with the ability to form reversible hydrogen bonds and coordination bonds with the substrate surface in a humid environment, enabling the coating to maintain interfacial adhesion even after contact with moisture. The network precursor, by introducing dynamic borate ester bonds, gives the cured coating network the chemical basis for dynamic covalent exchange and reconstruction under moisture-mediated conditions. In the synergistic functional filler system, the surface-hydroxylated hexagonal boron nitride nanosheets, with their two-dimensional sheet structure, form a meandering barrier path in the coating, extending the diffusion channel of corrosive media to the substrate. Simultaneously, their surface hydroxyl groups form hydrogen bonds with the polar groups in the resin network, dissipating stress energy through the reversible breaking and recombination of hydrogen bonds when the coating is subjected to dynamic stress, thus delaying macro-stress. The formation of cracks is observed. Chloride ion-responsive organic-inorganic hybrid layered fillers store repair agent monomers in the interlayer domain when the coating is intact. When microcracks are generated in the coating due to damage and chloride ions are introduced, the layered fillers release the repair agent monomers through an ion exchange mechanism. The catechol groups carried by the released repair agent monomers establish wet anchoring with the substrate surface exposed by the cracks, while their diol groups participate in the dynamic exchange reaction of the borate ester network, weaving the released repair agent into the reconstructing polymer network in a chemical bond manner, thereby completing the chemical repair of the crack area and the reconstruction of interfacial adhesion. The above components work synergistically in structure and function, enabling the ink coating to have barrier and stress dissipation capabilities in the intact state, and to autonomously initiate a cascade response repair process after microcracks are generated, overcoming the shortcomings of traditional protective inks that can only passively block and cannot actively repair damage.

[0007] Preferably, the surface-hydroxylated hexagonal boron nitride nanosheets are prepared by the following method: hexagonal boron nitride powder is dispersed in a mixed solvent of isopropanol and water, and after ultrasonic liquid-phase exfoliation, the supernatant containing the nanosheets is collected, and hydrogen peroxide aqueous solution is added for surface hydroxylation treatment under hydrothermal conditions. After washing and drying, the surface-hydroxylated hexagonal boron nitride nanosheets are obtained. The thickness of the surface-hydroxylated hexagonal boron nitride nanosheets is at the atomic level, and the surface is rich in hydroxyl groups.

[0008] By employing the above technical solution, ultrasonic liquid-phase exfoliation cleaves the original hexagonal boron nitride powder along its interlayer planes into nanosheets with few or even single layers, achieving atomic-level thickness and a larger aspect ratio. This allows for the construction of more tortuous penetration paths in the coating, improving barrier efficiency. The subsequent hydrothermal treatment step with hydrogen peroxide aqueous solution introduces hydroxyl functional groups onto the surface of the nanosheets. These hydroxyl groups improve the dispersibility and interfacial compatibility of the nanosheets in the resin system and provide active sites for forming hydrogen bonds with borate ester bonds and polar groups in the resin network. This enables the nanosheets to participate in stress dissipation mechanisms, resulting in a more significant effect in delaying crack initiation.

[0009] Preferably, in the network prepolymer, dopamine methacrylamide accounts for 15% to 25% of the total molar fraction of the monomers, hydroxyethyl acrylate accounts for 10% to 20%, and the balance is butyl methacrylate; the number average molecular weight of the network prepolymer is 15,000 to 50,000 g / mol, and the molecular weight distribution index is 1.5 to 2.5.

[0010] By adopting the above technical solution, dopamine methacrylamide, as a functional monomer, contains catechol groups on its side groups. These catechol groups are the structural units that impart wet adhesion to the coating. Controlling its molar fraction within the aforementioned range ensures functionality while maintaining the copolymer's solubility and processability. Hydroxyethyl acrylate provides hydroxyl groups, participating in the hydrogen bonding of hydroxyl groups on the filler surface and regulating the copolymer's hydrophilicity. Butyl methacrylate, as the main monomer, provides the basic mechanical properties and film-forming properties of the acrylate copolymer. Controlling the number-average molecular weight of the network prepolymer within the aforementioned range ensures that the prepolymer has the chain length to form a network structure, while avoiding excessively high molecular weight leading to excessive system viscosity, which is detrimental to subsequent filler dispersion and coating. Controlling the molecular weight distribution index within a suitable range is beneficial for the uniformity and repeatability of the coating performance.

[0011] Preferably, the synergistic functional packing system further includes 1% to 8% of a silane coupling agent by weight of the total packing material, wherein the silane coupling agent is γ-glycidoxypropyltrimethoxysilane or γ-methacryloyloxypropyltrimethoxysilane.

[0012] By adopting the above technical solution, the introduction of silane coupling agent constructs a chemical bridge between the inorganic filler surface and the organic resin matrix; after hydrolysis, the alkoxy group at one end of the coupling agent molecule condenses with the hydroxyl group on the filler surface, while the epoxy group or methacryloxy group at the other end undergoes a chemical reaction or physical entanglement with the active groups of the resin network during the curing process; this interface modification improves the uniformity of filler dispersion and interfacial bonding strength in the resin matrix, making it less likely for the filler to debond from the matrix when undertaking stress transmission and barrier functions, which is beneficial to maintaining the structural integrity of the coating under long-term dynamic load.

[0013] Preferably, in the network precursor, the terminal diol oligomer is polypropylene glycol with a number-average molecular weight of 800-1200 g / mol; the compound containing phenylboronic acid groups is pinacol 4-carboxyphenylboronic acid, and the molar ratio of the diol groups in the terminal diol oligomer to the phenylboronic acid groups in the pinacol 4-carboxyphenylboronic acid is 1:1.05-1:1.3.

[0014] By adopting the above technical solution, polypropylene glycol is selected as the terminal diol oligomer. Its flexible polyether backbone provides the chain segment mobility for the cured network, which is necessary for the dynamic exchange reaction of borate ester bonds triggered by moisture. The more sufficient the chain segment mobility, the higher the efficiency of network reconstruction during the repair process. Its number-average molecular weight is controlled within the above range to balance the mechanical strength and dynamic exchange activity of the network. 4-Carboxyphenylboronic acid pinacol ester is used as a compound containing phenylboronic acid groups. Its carboxyl group and glycol group undergo esterification to form borate ester bonds, and the pinacol ester protecting group is removed during subsequent curing or use to participate in dynamic exchange. The molar ratio of glycol groups to phenylboronic acid groups is set to a slight stoichiometric excess of glycol groups. The purpose is to retain unreacted active glycol terminal groups. These terminal groups serve as active sites for dynamic exchange reactions in the subsequent repair stage, participating in the chemical weaving process of the repair agent monomer, so that the repair reaction can more thoroughly complete the network structure reconstruction.

[0015] Secondly, this application provides a method for preparing ink for photovoltaic modules, which adopts the following technical solution: A method for preparing ink for photovoltaic modules includes the following steps: S1. Dissolve the network prepolymer and network precursor in a diluent and stir until homogeneous under light-protected conditions to obtain a resin base solution. S2. Hydroxylated hexagonal boron nitride nanosheets and chloride ion-responsive organic-inorganic hybrid layered fillers are added to a diluent in a certain proportion and ultrasonically dispersed to form a filler pre-dispersion slurry. S3. The pre-dispersed filler slurry obtained in step S2 is added to the resin base solution obtained in step S1 under stirring. It is dispersed at high speed under light-protected conditions. Then, curing initiator and additives are added. After vacuum degassing, the ink for photovoltaic modules is obtained.

[0016] By adopting the above technical solution, the preparation method of this application employs a step-by-step formulation and combination process route. First, the two network prepolymers are dissolved into a uniform resin base solution. Then, the two functional fillers are pre-dispersed separately and combined with the resin base. This process arrangement ensures that each component can achieve a fully dispersed and uniformly distributed state in the final ink. The surface-hydroxylated hexagonal boron nitride nanosheets and chloride ion-responsive organic-inorganic hybrid layered fillers are first ultrasonically pre-dispersed in the diluent. The ultrasonic cavitation effect is used to overcome the van der Waals forces between the nanosheet layers and the stacking of the hybrid layered fillers. The stacking tendency ensures that the two fillers are uniformly suspended in the dispersion medium in the form of single or few flakes, creating a prerequisite for the uniform compounding with the resin matrix in the subsequent process. After the filler pre-dispersion slurry is added to the resin matrix solution, it is dispersed at high speed, so that the filler particles are wrapped and wetted by the resin molecules under the action of shear force, forming a stable suspension system. The light-protected operation protects the photoinitiator from premature activation during preparation and storage, ensuring the initiation efficiency of the subsequent UV curing step. The vacuum degassing step eliminates residual air bubbles in the system, avoids pinhole defects in the coating after curing, and ensures the density and protective reliability of the coating.

[0017] Preferably, in step S1, the diluent is a mixed solvent of propylene glycol methyl ether acetate and butyl acetate, and the preparation method of the network prepolymer is as follows: dopamine methacrylamide, butyl methacrylate, and hydroxyethyl acrylate are dissolved in N,N-dimethylformamide, heated to 65-80°C under nitrogen protection, and azobisisobutyronitrile is added to initiate polymerization. The reaction time is 4-8 hours. After the reaction is completed, the prepolymer is obtained by precipitation, filtration, washing, and drying.

[0018] By adopting the above technical solution, a mixed solvent of propylene glycol methyl ether acetate and butyl acetate is selected as the diluent. The difference in boiling point and evaporation rate between the two solvents allows for gradient evaporation during the coating drying and post-baking stages, which is beneficial for coating leveling and dense film formation. The network prepolymer is synthesized using a solution free radical polymerization method. N,N-dimethylformamide has good solubility for all three acrylate monomers, ensuring that the polymerization is carried out in a homogeneous system. Nitrogen protection eliminates the quenching effect of oxygen molecules on free radicals, ensuring initiation efficiency and polymerization rate. The reaction temperature is controlled within the above range to ensure that azobisisobutyronitrile decomposes at a suitable rate to generate free radicals, maintaining a stable polymerization rate, while avoiding excessively high temperatures that could exacerbate chain transfer reactions and affect the controllability of the product molecular weight. After the reaction, the polymer is separated by precipitation. By selecting a precipitant that has good solubility for monomers but poor solubility for polymers, unreacted monomers and low molecular weight byproducts are removed. After washing and drying, a network prepolymer with high purity and a narrow molecular weight distribution is obtained.

[0019] Preferably, in step S1, the preparation method of the network precursor is as follows: the terminal diol oligomer and 4-carboxyphenylboronic acid pinacol ester are dissolved in toluene, p-toluenesulfonic acid is added as a catalyst, the mixture is heated under nitrogen protection and refluxed, and the esterification by-product water is removed by toluene-water azeotropy. The reaction time is 3-5 hours. After the reaction is completed, the solvent and unreacted substances are removed by vacuum distillation, and the mixture is dried under vacuum to obtain the network precursor.

[0020] By employing the above technical solution, the synthesis of the network precursor utilizes the esterification reaction of carboxyl and alcohol hydroxyl groups to introduce borate ester bonds between polymer segments. Toluene is selected as the reaction solvent, and its azeotropic properties with water allow the byproduct water generated during the esterification reaction to be continuously discharged from the system through a water separator, breaking the reaction equilibrium and promoting the esterification reaction in the forward direction, thereby increasing the formation rate of borate ester bonds. Toluenesulfonic acid is used as an acidic catalyst to lower the reaction activation energy, allowing the esterification to proceed smoothly under mild conditions. Nitrogen protection avoids the adverse effects of oxidation side reactions on the color and properties of the product under high-temperature reflux conditions. After the reaction, the solvent and unreacted small molecule compounds are removed by vacuum distillation, and residual trace moisture is removed by vacuum drying, preventing premature hydrolysis of borate ester bonds due to moisture during storage and ensuring the chemical stability of the precursor before use.

[0021] Preferably, in step S2, the preparation method of the chloride ion responsive organic-inorganic hybrid layered filler is as follows: first, magnesium-aluminum layered bimetallic hydroxide is calcined at 400-500℃ to obtain layered bimetallic composite oxide; then, the calcined product is added to an aqueous solution of the repair agent monomer; under nitrogen protection, the mixture is stirred at 50-70℃ for 8-16 hours for ion exchange reaction; after the reaction is completed, the mixture is centrifuged, washed, and dried to obtain the organic-inorganic hybrid layered filler of the intercalated repair agent monomer.

[0022] By adopting the above technical solution, magnesium-aluminum layered bimetallic hydroxides, after high-temperature calcination, remove the original carbonate ions and water molecules between the layers, transforming into layered bimetallic composite oxides. The layered structure is not destroyed by calcination, but the interlayer domains remain open and activated, possessing the ability to re-accept foreign anions or polar molecules. Adding the calcined product to the aqueous solution of the repair agent monomer causes a reconstruction effect in the solution environment, i.e., the reabsorption of water molecules and the repair agent monomer in the solution restores the layered bimetallic hydroxide structure. The anionic form or polar groups of the repair agent monomer are embedded in the interlayer domains during the reconstruction process. Nitrogen protection eliminates dissolved carbon dioxide in the solution, preventing carbonate ions from re-occupying interlayer sites and interfering with the intercalation efficiency of the repair agent monomer. Controlling the reaction temperature within the above range ensures the ion exchange rate while preventing chemical structural changes in the repair agent monomer due to high temperatures. After the reaction, centrifugation and thorough washing remove the free repair agent monomers adsorbed on the surface, ensuring that only monomers embedded in the interlayer domains are released via chloride ion triggering during subsequent service, achieving controllable response release characteristics.

[0023] Preferably, in step S3, the curing initiator is a compound system of photoinitiator and thermal initiator, and the weight ratio of photoinitiator to thermal initiator is 1.5:1 to 10:1, wherein the photoinitiator is 2-hydroxy-2-methyl-1-phenylpropanone or 1-hydroxycyclohexylphenyl ketone; the thermal initiator is benzoyl peroxide or azobisisobutyronitrile; and the initiator is added after the filler pre-dispersion slurry and resin base solution have been dispersed at high speed.

[0024] By adopting the above technical solution, a curing initiation system combining photoinitiation and thermal initiation is used to achieve step-by-step curing of the coating and a gradient increase in crosslinking density. The photoinitiator rapidly generates free radicals under ultraviolet irradiation, initiating the polymerization and crosslinking of acrylate double bonds in the network prepolymer, enabling the coating to achieve initial shaping in a short time, meeting the curing speed requirements of continuous production. The thermal initiator remains inert during the ultraviolet irradiation stage and begins to decompose and release free radicals during the subsequent post-baking heating stage, initiating secondary crosslinking of the double bonds or other polymeric groups retained in the network precursor, and promoting the full formation and dynamic exchange of borate ester bonds to reach equilibrium. The weight ratio of photoinitiator to thermal initiator is set within the above range to ensure the seamless coordination of the two initiation mechanisms. A higher proportion of photoinitiator ensures the initial shaping speed, while a moderate proportion of thermal initiator provides supplementary crosslinking in the subsequent post-baking stage without triggering excessive reactions. The timing of adding the curing initiator after the filler and resin are fully mixed avoids premature contact between the initiator and monomers in the system, preventing uncontrollable polymerization during storage or operation, thus ensuring the ink's operating window and process stability.

[0025] In summary, this application has the following beneficial effects: 1. Because this application uses an interpenetrating network prepolymer system containing network prepolymer and network precursor, combined with a synergistic functional filler system, the components work together to enable the ink coating to have barrier and stress dissipation capabilities in an intact state, and to autonomously initiate a cascade repair process after microcracks are generated, thereby achieving the effects of active self-repair and wet adhesion maintenance.

[0026] 2. In this application, surface-hydroxylated hexagonal boron nitride nanosheets are preferably used as functional filler components. The nanosheets are obtained with atomic-level thickness by ultrasonic liquid phase exfoliation and surface hydroxyl groups are introduced by hydrogen peroxide treatment under hydrothermal conditions. Their two-dimensional sheet structure forms meandering penetration barrier paths in the coating. The surface hydroxyl groups improve the dispersibility and interfacial compatibility of the filler in the resin system. At the same time, they form hydrogen bond networks with borate ester bonds and polar groups in the resin network to participate in the dissipation of stress energy, thereby achieving the effects of extending the diffusion channels of corrosive media and delaying the formation of microcracks.

[0027] 3. The method of this application involves stepwise preparation, in which the network prepolymer and network precursor are pre-dissolved into a uniform resin base solution, and the two functional fillers are ultrasonically pre-dispersed in a diluent before being high-speed dispersed and compounded with the resin base. Ultrasonic pre-dispersion avoids the aggregation and stacking tendency of nanofillers, allowing them to be uniformly suspended in the form of single or few flakes. High-speed dispersion allows the resin molecules to fully encapsulate and wet the filler particles to form a stable suspension system. Light-protected operation ensures the activity of the photoinitiator, and vacuum degassing eliminates residual bubbles to avoid pinhole defects after coating curing. Therefore, the method achieves uniform component dispersion, dense and complete coating, and good process stability.

[0028] 4. In this application, chloride ion-responsive organic-inorganic hybrid layered filler is preferred. Since the filler uses magnesium-aluminum layered bimetallic hydroxide as the matrix, the repair agent monomer is intercalated into the interlayer domain through calcination activation and ion exchange method. When the coating is intact, the repair agent monomer is stably stored. When chloride ions are introduced by microcracks, the chloride ions exchange with the interlayer anions, triggering the release of the repair agent monomer on demand. The release timing and release amount are automatically controlled by the invasion process of the corrosive medium, realizing the responsive matching of the repair process to the damage event, and obtaining the effect of supplying repair resources on demand and synchronizing with the crack propagation process. Attached Figure Description

[0029] Figure 1 This is a flowchart illustrating a method for preparing ink for photovoltaic modules according to this application; Figure 2 This is a schematic diagram showing the scratch healing rate test results of the embodiments and comparative examples in this application; Figure 3 This is a schematic diagram showing the bubble area detection results of the embodiments and comparative examples in this application; Figure 4This is a schematic diagram showing the 800-hour single-sided corrosion propagation width detection results of the embodiments and comparative examples in this application. Detailed Implementation

[0030] The present application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0031] Technical concept: This application discloses an ink for photovoltaic modules and its preparation method. It comprises the following raw materials: a self-healing resin base, a synergistic functional filler system, a curing initiator, a diluent, and additives. The preparation method is as follows: S1, dissolving the network prepolymer and network precursor in the diluent and stirring until homogeneous under light-protected conditions to obtain a resin base solution; S2, adding surface-hydroxylated hexagonal boron nitride nanosheets and chloride ion-responsive organic-inorganic hybrid layered fillers to the diluent in a specific ratio and ultrasonically dispersing to form a filler pre-dispersion slurry; S3, adding the filler pre-dispersion slurry to the resin base solution under stirring and high-speed dispersion under light-protected conditions, followed by the addition of the curing initiator and additives, and then vacuum degassing to obtain the ink for photovoltaic modules.

[0032] This application employs an interpenetrating network prepolymer system comprising network prepolymer and network precursor, combined with a synergistic functional filler system. The synergistic effect of each component enables the ink coating to possess barrier and stress dissipation capabilities in its intact state, and to autonomously initiate a cascade repair process after microcracks are generated, thereby achieving the effects of active self-repair and wet adhesion maintenance.

[0033] Example 1: This example provides an ink for photovoltaic modules, comprising the following raw materials in parts by weight: 45 parts self-healing resin base; 15 parts synergistic functional filler system; 1 part curing initiator; 10 parts diluent; 0.5 parts additives; the self-healing resin base is an interpenetrating network prepolymer system, comprising a network prepolymer and a network precursor; the network prepolymer is an acrylate copolymer containing catechol side groups, obtained by free radical polymerization of a monomer mixture containing dopamine methacrylamide, butyl methacrylate, and hydroxyethyl acrylate; the network precursor is a polymer containing dynamic borate ester bonds... The cross-linked prepolymer is prepared by dehydration condensation reaction of terminal diol oligomers and compounds containing phenylboronic acid groups, and retains unreacted active diol end groups; the synergistic functional filler system is composed of surface-hydroxylated hexagonal boron nitride nanosheets and chloride ion-responsive organic-inorganic hybrid layered fillers in a mass ratio of 1:0.3; the chloride ion-responsive organic-inorganic hybrid layered filler uses layered bimetallic hydroxide as the matrix, and repair agent monomers are intercalated in its interlayer domains by ion exchange, and the repair agent monomers carry catechol groups and diol groups; the additive is a leveling agent.

[0034] Surface-hydroxylated hexagonal boron nitride nanosheets were prepared by the following method: hexagonal boron nitride powder was dispersed in a mixed solvent of isopropanol and water, and after ultrasonic liquid phase exfoliation, the supernatant containing nanosheets was collected, and hydrogen peroxide aqueous solution was added for surface hydroxylation treatment under hydrothermal conditions. After washing and drying, the hexagonal boron nitride nanosheets with surface hydroxylation were obtained. The thickness of the surface-hydroxylated hexagonal boron nitride nanosheets was at the atomic level, and the surface was rich in hydroxyl groups.

[0035] In the network prepolymer, dopamine methacrylamide accounts for 15% of the total molar fraction of the monomers, hydroxyethyl acrylate accounts for 10%, and the balance is butyl methacrylate; the number average molecular weight of the network prepolymer is 15000 g / mol, and the molecular weight distribution index is 1.5.

[0036] The synergistic functional packing system also contains a silane coupling agent accounting for 1% of the total mass of the packing. The silane coupling agent is γ-glycidoxypropyltrimethoxysilane.

[0037] The above-mentioned method for preparing ink for photovoltaic modules includes the following steps: S1. Dissolve the network prepolymer and network precursor in a diluent and stir until homogeneous under light-protected conditions to obtain a resin base solution.

[0038] The diluent is a mixed solvent of propylene glycol methyl ether acetate and butyl acetate.

[0039] The preparation method of the network prepolymer is as follows: dopamine methacrylamide, butyl methacrylate, and hydroxyethyl acrylate are dissolved in N,N-dimethylformamide, heated to 65°C under nitrogen protection, and azobisisobutyronitrile is added to initiate polymerization. The reaction time is 4 hours. After the reaction is completed, the prepolymer is obtained by precipitation, filtration, washing and drying.

[0040] The preparation method of the network precursor is as follows: the terminal diol oligomer and 4-carboxyphenylboronic acid pinacol ester are dissolved in toluene, p-toluenesulfonic acid is added as a catalyst, and the mixture is heated under nitrogen protection and refluxed. The esterification by-product water is removed by toluene-water azeotropy. The reaction time is 3 h. After the reaction is completed, the solvent and unreacted substances are removed by vacuum distillation, and the mixture is dried under vacuum to obtain the network precursor. The terminal diol oligomer is polypropylene glycol with a number average molecular weight of 800 g / mol. The compound containing phenylboronic acid groups is 4-carboxyphenylboronic acid pinacol ester, and the molar ratio of the diol groups in the terminal diol oligomer to the phenylboronic acid groups in the 4-carboxyphenylboronic acid pinacol ester is 1:1.05.

[0041] S2. Surface-hydroxylated hexagonal boron nitride nanosheets and chloride ion-responsive organic-inorganic hybrid layered fillers are added to the diluent in proportion and ultrasonically dispersed to form a filler pre-dispersion slurry.

[0042] The preparation method of chloride ion responsive organic-inorganic hybrid layered filler is as follows: first, magnesium-aluminum layered bimetallic hydroxide is calcined at 400℃ to obtain layered bimetallic composite oxide. Then, the calcined product is added to the aqueous solution of the repair agent monomer. Under nitrogen protection, the ion exchange reaction is carried out at 50℃ for 8 hours with stirring. After the reaction is completed, the filler is centrifuged, washed and dried to obtain the organic-inorganic hybrid layered filler of the intercalated repair agent monomer.

[0043] S3. The pre-dispersed filler slurry obtained in step S2 is added to the resin base solution obtained in step S1 under stirring. It is dispersed at high speed under light-protected conditions. Then, curing initiator and additives are added. After vacuum degassing, the ink for photovoltaic modules is obtained.

[0044] The curing initiator is a compound system of photoinitiator and thermal initiator, with a weight ratio of 1.5:1. The photoinitiator is 2-hydroxy-2-methyl-1-phenylpropanone, and the thermal initiator is benzoyl peroxide. It is added after the filler pre-dispersion slurry and resin base solution have been dispersed at high speed.

[0045] Example 2: This example provides an ink for photovoltaic modules, comprising the following raw materials in parts by weight: 57.5 parts of self-healing resin base; 22.5 parts of synergistic functional filler system; 3 parts of curing initiator; 20 parts of diluent; and 1.75 parts of additives. The self-healing resin base is an interpenetrating network prepolymer system, comprising a network prepolymer and a network precursor. The network prepolymer is an acrylate copolymer containing catechol side groups, obtained by free radical polymerization of a monomer mixture containing dopamine methacrylamide, butyl methacrylate, and hydroxyethyl acrylate. The network precursor is a mixture containing dynamic boric acid... The cross-linked prepolymer of ester bonds is prepared by dehydration condensation reaction of terminal diol oligomers and compounds containing phenylboronic acid groups, and retains unreacted active diol end groups; the synergistic functional filler system is composed of surface-hydroxylated hexagonal boron nitride nanosheets and chloride ion-responsive organic-inorganic hybrid layered fillers in a mass ratio of 1:0.9; the chloride ion-responsive organic-inorganic hybrid layered filler uses layered bimetallic hydroxide as the matrix, and repair agent monomers are intercalated in its interlayer domains by ion exchange, and the repair agent monomers carry catechol groups and diol groups; the additive is an antifoaming agent.

[0046] Surface-hydroxylated hexagonal boron nitride nanosheets were prepared by the following method: hexagonal boron nitride powder was dispersed in a mixed solvent of isopropanol and water, and after ultrasonic liquid phase exfoliation, the supernatant containing nanosheets was collected, and hydrogen peroxide aqueous solution was added for surface hydroxylation treatment under hydrothermal conditions. After washing and drying, the hexagonal boron nitride nanosheets with surface hydroxylation were obtained. The thickness of the surface-hydroxylated hexagonal boron nitride nanosheets was at the atomic level, and the surface was rich in hydroxyl groups.

[0047] In the network prepolymer, dopamine methacrylamide accounts for 20% of the total molar fraction of the monomers, hydroxyethyl acrylate accounts for 15%, and the balance is butyl methacrylate; the number average molecular weight of the network prepolymer is 32,500 g / mol, and the molecular weight distribution index is 2.0.

[0048] The synergistic functional packing system also contains a silane coupling agent accounting for 4.5% of the total mass of the packing. The silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane.

[0049] The above-mentioned method for preparing ink for photovoltaic modules includes the following steps: S1. Dissolve the network prepolymer and network precursor in a diluent and stir until homogeneous under light-protected conditions to obtain a resin base solution.

[0050] The diluent is a mixed solvent of propylene glycol methyl ether acetate and butyl acetate.

[0051] The preparation method of the network prepolymer is as follows: dopamine methacrylamide, butyl methacrylate, and hydroxyethyl acrylate are dissolved in N,N-dimethylformamide, heated to 72.5℃ under nitrogen protection, and azobisisobutyronitrile is added to initiate polymerization. The reaction time is 6 hours. After the reaction is completed, the prepolymer is obtained by precipitation, filtration, washing and drying.

[0052] The preparation method of the network precursor is as follows: the terminal diol oligomer and 4-carboxyphenylboronic acid pinacol ester are dissolved in toluene, p-toluenesulfonic acid is added as a catalyst, and the mixture is heated under nitrogen protection and refluxed. The esterification by-product water is removed by toluene-water azeotropy. The reaction time is 4 h. After the reaction is completed, the solvent and unreacted substances are removed by vacuum distillation, and the mixture is dried under vacuum to obtain the network precursor. The terminal diol oligomer is polypropylene glycol with a number average molecular weight of 1000 g / mol. The compound containing phenylboronic acid groups is 4-carboxyphenylboronic acid pinacol ester, and the molar ratio of the diol groups in the terminal diol oligomer to the phenylboronic acid groups in the 4-carboxyphenylboronic acid pinacol ester is 1:1.175.

[0053] S2. Surface-hydroxylated hexagonal boron nitride nanosheets and chloride ion-responsive organic-inorganic hybrid layered fillers are added to the diluent in proportion and ultrasonically dispersed to form a filler pre-dispersion slurry.

[0054] The preparation method of chloride ion responsive organic-inorganic hybrid layered filler is as follows: first, magnesium-aluminum layered bimetallic hydroxide is calcined at 450℃ to obtain layered bimetallic composite oxide. Then, the calcined product is added to the aqueous solution of the repair agent monomer. Under nitrogen protection, the ion exchange reaction is stirred at 60℃ for 12 hours. After the reaction is completed, the filler is centrifuged, washed and dried to obtain the organic-inorganic hybrid layered filler of the intercalated repair agent monomer.

[0055] S3. The pre-dispersed filler slurry obtained in step S2 is added to the resin base solution obtained in step S1 under stirring. It is dispersed at high speed under light-protected conditions. Then, curing initiator and additives are added. After vacuum degassing, the ink for photovoltaic modules is obtained.

[0056] The curing initiator is a compound system of photoinitiator and thermal initiator, with a weight ratio of 5.75:1. The photoinitiator is 1-hydroxycyclohexylphenyl ketone, and the thermal initiator is azobisisobutyronitrile. It is added after the filler pre-dispersion slurry and resin base solution have been dispersed at high speed.

[0057] Example 3: This example provides an ink for photovoltaic modules, comprising the following raw materials in parts by weight: 70 parts of self-healing resin base; 30 parts of synergistic functional filler system; 5 parts of curing initiator; 30 parts of diluent; and 3 parts of additives. The self-healing resin base is an interpenetrating network prepolymer system, comprising a network prepolymer and a network precursor. The network prepolymer is an acrylate copolymer containing catechol side groups, obtained by free radical polymerization of a monomer mixture containing dopamine methacrylamide, butyl methacrylate, and hydroxyethyl acrylate. The network precursor is an interpenetrating network containing dynamic borate ester bonds. The prepolymer is prepared by dehydration condensation reaction of terminal diol oligomers and compounds containing phenylboronic acid groups, and retains unreacted active diol end groups; the synergistic functional filler system is composed of surface-hydroxylated hexagonal boron nitride nanosheets and chloride ion-responsive organic-inorganic hybrid layered fillers in a mass ratio of 1:1.5; the chloride ion-responsive organic-inorganic hybrid layered filler uses layered bimetallic hydroxide as the matrix, and repair agent monomers are intercalated in its interlayer domains by ion exchange. The repair agent monomers carry catechol groups and diol groups; the additive is a leveling agent.

[0058] Surface-hydroxylated hexagonal boron nitride nanosheets were prepared by the following method: hexagonal boron nitride powder was dispersed in a mixed solvent of isopropanol and water, and after ultrasonic liquid phase exfoliation, the supernatant containing nanosheets was collected, and hydrogen peroxide aqueous solution was added for surface hydroxylation treatment under hydrothermal conditions. After washing and drying, the hexagonal boron nitride nanosheets with surface hydroxylation were obtained. The thickness of the surface-hydroxylated hexagonal boron nitride nanosheets was at the atomic level, and the surface was rich in hydroxyl groups.

[0059] In the network prepolymer, dopamine methacrylamide accounts for 25% of the total molar fraction of the monomers, hydroxyethyl acrylate accounts for 20%, and the balance is butyl methacrylate; the number average molecular weight of the network prepolymer is 50,000 g / mol, and the molecular weight distribution index is 2.5.

[0060] The synergistic functional packing system also contains 8% of a silane coupling agent by mass, which is γ-glycidoxypropyltrimethoxysilane.

[0061] The above-mentioned method for preparing ink for photovoltaic modules includes the following steps: S1. Dissolve the network prepolymer and network precursor in a diluent and stir until homogeneous under light-protected conditions to obtain a resin base solution.

[0062] The diluent is a mixed solvent of propylene glycol methyl ether acetate and butyl acetate.

[0063] The preparation method of the network prepolymer is as follows: dopamine methacrylamide, butyl methacrylate, and hydroxyethyl acrylate are dissolved in N,N-dimethylformamide, heated to 80°C under nitrogen protection, and azobisisobutyronitrile is added to initiate polymerization. The reaction time is 8 hours. After the reaction is completed, the prepolymer is obtained by precipitation, filtration, washing and drying.

[0064] The preparation method of the network precursor is as follows: the terminal diol oligomer and 4-carboxyphenylboronic acid pinacol ester are dissolved in toluene, p-toluenesulfonic acid is added as a catalyst, and the mixture is heated under nitrogen protection and refluxed. The esterification by-product water is removed by toluene-water azeotropy. The reaction time is 5 h. After the reaction is completed, the solvent and unreacted substances are removed by vacuum distillation, and the mixture is dried under vacuum to obtain the network precursor. The terminal diol oligomer is polypropylene glycol with a number average molecular weight of 1200 g / mol. The compound containing phenylboronic acid groups is 4-carboxyphenylboronic acid pinacol ester, and the molar ratio of the diol groups in the terminal diol oligomer to the phenylboronic acid groups in the 4-carboxyphenylboronic acid pinacol ester is 1:1.3.

[0065] S2. Surface-hydroxylated hexagonal boron nitride nanosheets and chloride ion-responsive organic-inorganic hybrid layered fillers are added to the diluent in proportion and ultrasonically dispersed to form a filler pre-dispersion slurry.

[0066] The preparation method of chloride ion responsive organic-inorganic hybrid layered filler is as follows: first, magnesium-aluminum layered bimetallic hydroxide is calcined at 500℃ to obtain layered bimetallic composite oxide. Then, the calcined product is added to the aqueous solution of the repair agent monomer. Under nitrogen protection, the ion exchange reaction is carried out at 70℃ for 16 hours with stirring. After the reaction is completed, the filler is centrifuged, washed and dried to obtain the organic-inorganic hybrid layered filler of the intercalated repair agent monomer.

[0067] S3. The pre-dispersed filler slurry obtained in step S2 is added to the resin base solution obtained in step S1 under stirring. It is dispersed at high speed under light-protected conditions. Then, curing initiator and additives are added. After vacuum degassing, the ink for photovoltaic modules is obtained.

[0068] The curing initiator is a compound system of photoinitiator and thermal initiator, with a weight ratio of 10:1. The photoinitiator is 2-hydroxy-2-methyl-1-phenylpropanone, and the thermal initiator is benzoyl peroxide. It is added after the filler pre-dispersion slurry and resin base solution have been dispersed at high speed.

[0069] Comparative Example 1: This comparative example refers to the content of Example 1, except that the self-healing resin matrix does not contain a network precursor, that is, it only uses a network prepolymer as a single resin component and does not exist in the form of an interpenetrating network prepolymer system. The rest of the content is the same as that of Example 1.

[0070] Comparative Example 2: This comparative example refers to the content of Example 1, except that the synergistic functional filler system does not contain surface-hydroxylated hexagonal boron nitride nanosheets, and only uses chloride ion-responsive organic-inorganic hybrid layered filler as a single filler component. The rest of the content is the same as in Example 1.

[0071] Comparative Example 3: This comparative example refers to the content of Example 1, except that the synergistic functional filler system does not contain chloride ion responsive organic-inorganic hybrid layered filler, but only uses surface-hydroxylated hexagonal boron nitride nanosheets as a single filler component, and the rest is the same as Example 1.

[0072] Comparative Example 4: This comparative example refers to the content of Example 1, except that the network prepolymer does not contain dopamine methacrylamide, that is, the network prepolymer is an acrylate copolymer obtained by free radical polymerization of butyl methacrylate and hydroxyethyl acrylate, and does not contain catechol side groups. The rest of the contents are the same as those in Example 1.

[0073] Comparative Example 5: This comparative example refers to the content of Example 1, except that the surface-hydroxylated hexagonal boron nitride nanosheets were not subjected to surface hydroxylation treatment with hydrogen peroxide aqueous solution under hydrothermal conditions during the preparation process. That is, the hexagonal boron nitride nanosheets were only obtained by ultrasonic liquid phase exfoliation without introducing surface hydroxyl groups. The rest of the content is the same as that of Example 1.

[0074] Comparative Example 6: This comparative example refers to the content of Example 1, except that the molar ratio of the diol group in the terminal diol oligomer of the network precursor to the phenylboronic acid group of 4-carboxyphenylboronic acid pinacol ester is 1:1, that is, there is no stoichiometric excess of the diol group relative to the phenylboronic acid group, and no unreacted active diol end groups are retained. The rest is the same as Example 1.

[0075] Performance testing Sample Preparation: Inks for each example and comparative example were prepared according to the formulation and preparation method of the embodiments and comparative examples. Polyethylene terephthalate film for photovoltaic backsheets was selected as the substrate. After the surface was wiped clean with anhydrous ethanol, each ink was uniformly coated onto the substrate surface using a wire bar coater. The wet film thickness was controlled so that the coating thickness after curing was within the range of 25μm to 35μm. The coated samples were immediately placed on a UV curing conveyor belt and irradiated under a UV lamp with a wavelength of 365nm and a light intensity of about 80mW / cm² to rapidly crosslink and set the coating. The samples were then transferred to a forced-air drying oven and post-baked at 80°C for 2 hours. After naturally cooling to room temperature, the coated samples of each example and comparative example were obtained for subsequent performance testing.

[0076] Adhesion testing: The cross-cut adhesion test was conducted according to GB / T9286 standard. The coating samples of each embodiment and comparative example were placed in a constant temperature and humidity chamber at 35°C and 95% relative humidity. After being kept in a humid environment for 24 hours, they were removed and immediately cross-cutted vertical grid lines were made on the coating surface using a cross-cutting tool with a spacing of 2 mm and a number of 6 x 6 lines. Pressure-sensitive adhesive tape was then applied to the grid area and quickly peeled off at an angle of approximately 60°. The peeling of the coating in the grid area was observed using a magnifying glass, and the wet adhesion level was evaluated according to the grading method specified in the standard.

[0077] Self-healing performance testing: For each embodiment and comparative example, the coated samples were pre-marked with a scalpel blade, creating straight scratches approximately 20 μm wide and 1 cm long to simulate microcrack damage during service. The scratched samples were then placed in a constant temperature and humidity chamber at 35°C and 95% relative humidity for 12 h, 24 h, and 48 h, respectively. At each time point, the samples were removed, and the scratch morphology was observed using a metallographic microscope. The degree of healing of the scratch width over time was recorded. Simultaneously, an adhesion test was used to examine the change in adhesion of the scratched area before and after repair, in order to evaluate the self-healing ability of the coating.

[0078] Salt spray resistance testing: Neutral salt spray test was conducted according to GB / T1771 standard; crosses were made on the surface of the coating samples of each example and comparative example, with the crosses reaching the substrate. The samples were placed in the salt spray test chamber at an angle of 15° to 25° with respect to the vertical direction. The sodium chloride solution concentration in the test chamber was 50 g / L, the pH value was controlled between 6.5 and 7.2, the test chamber temperature was 35℃, and the continuous spraying time was 800 h. During the test, the coating was observed regularly for signs of blistering, rusting, peeling, or other damage. After the test, the single-sided corrosion spread width at the crosses was measured to evaluate the protective durability of the coating in a high salt spray environment.

[0079] Microscopic morphology observation and testing of the coating: The coating samples of each embodiment and comparative example were fractured in liquid nitrogen to obtain the coating cross-section. The microscopic morphology of the cross-section was observed using a cold field emission scanning electron microscope under an accelerating voltage of 5kV. The focus was on examining the dispersion state of the filler in the resin matrix, the interfacial bonding between the filler and the resin matrix, the presence of pores or defects inside the coating, and the orientation of the layered filler in the coating, in order to evaluate the influence of the preparation method on the density and compositional uniformity of the coating.

[0080] Ion exchange responsiveness testing: After scratching the coating samples of each embodiment and comparative example, they were immersed in a neutral salt solution containing 3.5% chloride ions at a temperature of 35°C for 72 hours. After removing the samples, the surface was rinsed with deionized water and dried. X-ray diffraction was used to analyze the changes in the interlayer spacing of the filler in the scratched area. At the same time, Fourier transform infrared spectroscopy was used to analyze the changes in the surface chemical groups in the scratched area to examine whether the chloride ion-responsive organic-inorganic hybrid layered filler undergoes ion exchange and releases remediation agent monomers after chloride ion invasion, and to evaluate the responsiveness of the remediation resources to supply on demand.

[0081] Table 1: Test results of wet adhesion and self-healing performance of each embodiment and comparative example Example 1 1 47 78 94 91 Example 2 0 53 83 96 94 Example 3 1 49 80 93 90 Comparative Example 1 3 8 12 16 34 Comparative Example 2 2 31 52 68 62 Comparative Example 3 2 18 25 31 45 Comparative Example 4 4 43 71 89 38 Comparative Example 5 2 42 73 90 71 Comparative Example 6 1 22 40 55 53 Note: Adhesion rating is evaluated according to GB / T 9286 standard. Grade 0 means the cut edge is completely smooth and there is no peeling. Grade 4 means the coating peels off over a large area along the cut edge. The scratch healing rate is calculated by measuring the change in scratch width before and after healing using a metallographic microscope. The adhesion retention rate after repair is the proportion of the scratch area that recovers to the original adhesion rating after 48 hours of repair.

[0082] Table 2: Salt spray resistance test results of each embodiment and comparative example Example 1 0 0 0.3 0.4 no Example 2 0 0 0.1 0.2 no Example 3 0 0 0.5 0.6 no Comparative Example 1 0.8 3.2 8.7 3.5 yes Comparative Example 2 0 0.4 2.1 1.4 no Comparative Example 3 0 0.9 3.8 2.3 yes Comparative Example 4 0.2 1.5 5.2 2.7 yes Comparative Example 5 0 0.3 2.6 1.8 no Comparative Example 6 0 0.5 3.1 2.0 no Note: The blistering area is assessed as a percentage of the total area of ​​the cross-shaped area; the unilateral corrosion spread width is the maximum distance the corrosion extends from the cross-shaped line to one side of the coating.

[0083] Table 3: Coating microstructure and ion exchange responsiveness test results of each embodiment and comparative example Example 1 uniform small amount Partial orientation 18.5 weaken Example 2 uniform Very few Good Orientation 21.7 Significantly reduced Example 3 Relatively uniform small amount Partial orientation 17.8 weaken Comparative Example 1 uniform small amount Partial orientation 19.2 weaken Comparative Example 2 uniform small amount Irregular arrangement 20.3 weaken Comparative Example 3 Relatively uniform small amount Partial orientation — — Comparative Example 4 uniform small amount Partial orientation 18.9 weaken Comparative Example 5 There is a slight reunion small amount Partial orientation 19.6 weaken Comparative Example 6 uniform small amount Partial orientation 13.2 Slightly weakened Note: The uniformity of filler dispersion and the number of cross-sectional pores were evaluated by scanning electron microscopy; the orientation degree of layered filler is the degree to which the filler layers are parallel to the substrate surface; the change rate of interlayer spacing after ion exchange was calculated by X-ray diffraction analysis of the characteristic diffraction peak shifts of layered bimetallic hydroxides; the change of infrared absorption peaks of characteristic groups of repair additives reflects the degree of monomer release of repair additives, "—" indicates that this item was not tested because Comparative Example 3 did not contain chloride ion responsive organic-inorganic hybrid layered filler.

[0084] Example Conclusion: See appendix Figure 1 -Appendix Figure 4 Based on the technical solutions of various embodiments and comparative examples, the following conclusions can be drawn: Combining Examples 1-3 and Comparative Example 1 with Tables 1 and 2, it can be seen that when the self-healing resin matrix does not contain a network precursor and only uses the network prepolymer as a single resin component, the coating loses the network dynamic exchange and reconstruction capabilities provided by the dynamic borate ester bonds, the scratch healing rate decreases significantly, the salt spray resistance deteriorates significantly, and large-area blistering and peeling occur in the later stages of the salt spray test. In contrast, Examples 1-3, through the synergistic cooperation between the network prepolymer and the network precursor in the interpenetrating network prepolymer system, the network prepolymer provides wet adhesion capability, and the network precursor endows the coating with self-healing function under moisture-mediated conditions. The combined effect of the two enables the coating to autonomously initiate the repair process after the microcracks are generated, thereby achieving a comprehensive effect of long-term protection and damage self-healing.

[0085] Based on Examples 1-3 and Comparative Example 2, and in conjunction with Tables 2 and 3, it can be seen that when the synergistic functional filler system does not contain surface-hydroxylated hexagonal boron nitride nanosheets, the coating lacks the meandering barrier path formed by the two-dimensional layered structure. The diffusion channel of the corrosive medium along the coating thickness direction is shortened, and the bubbling area and corrosion spread width in the salt spray test are both increased. After introducing surface-hydroxylated hexagonal boron nitride nanosheets in Examples 1-3, the nanosheets, with their atomic layer thickness and large aspect ratio, construct tortuous penetration paths in the coating, effectively extending the diffusion distance of water molecules and chloride ions. At the same time, the hydroxyl groups on the surface of the nanosheets form hydrogen bonds with the resin network to dissipate stress, delaying the generation of microcracks, thereby improving the long-term protective reliability of the coating.

[0086] Based on Examples 1-3 and Comparative Example 3, and in conjunction with Table 1, it can be seen that when the synergistic functional filler system does not contain chloride ion-responsive organic-inorganic hybrid layered fillers, the coating lacks an on-demand supply mechanism for repair agent monomers after microcracks are generated. The self-healing process relies solely on the dynamic exchange reaction of the resin matrix itself, limiting both the degree of scratch healing and the retention rate of adhesion after repair. The hybrid layered fillers introduced in Examples 1-3 stably store repair agent monomers when the coating is intact, and trigger their release upon chloride ion intrusion. The catechol groups carried by the released repair agent monomers establish a wet anchorage with the crack-exposed substrate, and the diol groups participate in the dynamic exchange reaction of the borate ester network, elevating the repair behavior from simple physical filling to chemical bonding repair, thereby improving repair efficiency and repair quality.

[0087] As can be seen from Examples 1-3 and Comparative Example 4, and Table 1, when the network prepolymer does not contain dopamine methacrylamide and lacks catechol side groups, the reversible hydrogen bonding and coordination bonding between the coating and the substrate are lost in a wet environment, the wet adhesion level decreases significantly, and the adhesion retention rate after repair is also severely affected. In Examples 1-3, by introducing a copolymer structure containing catechol side groups, the coating can establish a strong wet bond with the substrate surface under humid conditions. Even during the microcrack repair process, the catechol groups in the released repair agent monomer can form an anchor on the fresh substrate surface exposed by the crack, ensuring the effective reconstruction of the interfacial adhesion in the repair area.

[0088] Combining Examples 1-3 and Comparative Example 5 with Tables 1 and 3, it can be seen that when hexagonal boron nitride nanosheets are only subjected to ultrasonic liquid phase exfoliation without surface hydroxylation treatment, the interfacial compatibility between the nanosheets and the resin matrix is ​​insufficient, the uniformity of filler dispersion decreases and slight agglomeration occurs, affecting the uniformity of stress transmission within the coating and slightly reducing the self-healing efficiency. In Examples 1-3, after introducing surface hydroxyl groups through hydrothermal treatment with hydrogen peroxide aqueous solution, the hydroxyl groups improve the dispersibility of the nanosheets in the resin system and form a stable hydrogen bond network with the borate ester bonds and polar groups in the resin network, enabling the nanosheets to effectively participate in stress dissipation and barrier protection, realizing a functional leap from simple physical filling to chemical synergy between the filler and the resin matrix.

[0089] Based on Examples 1-3 and Comparative Example 6, and in conjunction with Tables 1 and 3, it can be seen that when the molar ratio of diol groups to phenylboronic acid groups in the network precursor is stoichiometric and unreacted active diol end groups are not retained, the coating lacks sufficient active sites to participate in the dynamic exchange reaction during the repair stage. The interlayer spacing changes little after ion exchange, the chemical weaving efficiency of the repair aid monomer decreases, and the scratch healing rate and adhesion retention rate after repair both decline. In Examples 1-3, by controlling a slight stoichiometric excess of diol groups, unreacted active diol end groups are retained. These end groups act as active anchors for dynamic exchange during the repair stage, effectively capturing the released repair aid monomers and weaving them into the reconstructed network, thus making the repair reaction more complete.

[0090] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. An ink for photovoltaic modules, characterized in that, The raw materials comprise the following parts by weight: self-healing resin base: 45-70 parts; synergistic functional filler system: 15-30 parts; curing initiator: 1-5 parts; diluent: 10-30 parts; and additives: 0.5-3 parts; wherein, the self-healing resin base is an interpenetrating network prepolymer system, comprising a network prepolymer and a network precursor; the network prepolymer is an acrylate copolymer containing catechol side groups, obtained by free radical polymerization of a monomer mixture containing dopamine methacrylamide, butyl methacrylate, and hydroxyethyl acrylate; the network precursor is a crosslinked prepolymer containing dynamic borate ester bonds. The product is prepared by dehydration condensation reaction of terminal diol oligomers and compounds containing phenylboronic acid groups, retaining unreacted active diol end groups; the synergistic functional filler system is composed of surface-hydroxylated hexagonal boron nitride nanosheets and chloride ion-responsive organic-inorganic hybrid layered fillers at a mass ratio of 1:0.3 to 1:1.5; the chloride ion-responsive organic-inorganic hybrid layered filler uses layered bimetallic hydroxide as a matrix, and repair agent monomers are intercalated in its interlayer domains by ion exchange, the repair agent monomers carrying both catechol groups and diol groups; the additives are leveling agents or defoamers.

2. The ink for photovoltaic modules according to claim 1, characterized in that, The surface-hydroxylated hexagonal boron nitride nanosheets are prepared by the following method: hexagonal boron nitride powder is dispersed in a mixed solvent of isopropanol and water, and after ultrasonic liquid-phase exfoliation, the supernatant containing the nanosheets is collected, and hydrogen peroxide aqueous solution is added for surface hydroxylation treatment under hydrothermal conditions. After washing and drying, the surface-hydroxylated hexagonal boron nitride nanosheets are obtained. The thickness of the surface-hydroxylated hexagonal boron nitride nanosheets is at the atomic level, and the surface is rich in hydroxyl groups.

3. The ink for photovoltaic modules according to claim 1, characterized in that, In the network prepolymer, dopamine methacrylamide accounts for 15% to 25% of the total molar fraction of the monomers, hydroxyethyl acrylate accounts for 10% to 20%, and the balance is butyl methacrylate; the number average molecular weight of the network prepolymer is 15,000 to 50,000 g / mol, and the molecular weight distribution index is 1.5 to 2.

5.

4. The ink for photovoltaic modules according to claim 1, characterized in that, The synergistic functional packing system also contains 1% to 8% of a silane coupling agent by weight of the total packing material. The silane coupling agent is γ-glycidoxypropyltrimethoxysilane or γ-methacryloyloxypropyltrimethoxysilane.

5. The ink for photovoltaic modules according to claim 1, characterized in that, In the network precursor, the terminal diol oligomer is polypropylene glycol with a number average molecular weight of 800-1200 g / mol; the compound containing phenylboronic acid groups is pinacol 4-carboxyphenylboronic acid, and the molar ratio of the diol groups in the terminal diol oligomer to the phenylboronic acid groups in the pinacol 4-carboxyphenylboronic acid is 1:1.05-1:1.

3.

6. A method for preparing ink for photovoltaic modules, characterized in that, The ink for a photovoltaic module as described in any one of claims 1-4 comprises the following steps: S1. Dissolve the network prepolymer and network precursor in a diluent and stir until homogeneous under light-protected conditions to obtain a resin base solution. S2. Hydroxylated hexagonal boron nitride nanosheets and chloride ion-responsive organic-inorganic hybrid layered fillers are added to a diluent in a certain proportion and ultrasonically dispersed to form a filler pre-dispersion slurry. S3. The pre-dispersed filler slurry obtained in step S2 is added to the resin base solution obtained in step S1 under stirring. It is dispersed at high speed under light-protected conditions. Then, curing initiator and additives are added. After vacuum degassing, the ink for photovoltaic modules is obtained.

7. The method for preparing ink for photovoltaic modules according to claim 6, characterized in that, In step S1, the diluent is a mixed solvent of propylene glycol methyl ether acetate and butyl acetate. The preparation method of the network prepolymer is as follows: dopamine methacrylamide, butyl methacrylate, and hydroxyethyl acrylate are dissolved in N,N-dimethylformamide, heated to 65-80°C under nitrogen protection, and azobisisobutyronitrile is added to initiate polymerization. The reaction time is 4-8 hours. After the reaction is completed, the prepolymer is obtained by precipitation, filtration, washing, and drying.

8. A method for preparing ink for photovoltaic modules according to claim 6, characterized in that, In step S1, the preparation method of the network precursor is as follows: the terminal diol oligomer and 4-carboxyphenylboronic acid pinacol ester are dissolved in toluene, p-toluenesulfonic acid is added as a catalyst, and the mixture is heated under nitrogen protection and refluxed. The esterification by-product water is removed by toluene-water azeotropy. The reaction time is 3-5 hours. After the reaction is completed, the solvent and unreacted substances are removed by vacuum distillation, and the mixture is dried under vacuum to obtain the network precursor.

9. A method for preparing ink for photovoltaic modules according to claim 6, characterized in that, In step S2, the preparation method of the chloride ion responsive organic-inorganic hybrid layered filler is as follows: first, magnesium-aluminum layered bimetallic hydroxide is calcined at 400-500℃ to obtain layered bimetallic composite oxide; then, the calcined product is added to the aqueous solution of the repair agent monomer; under nitrogen protection, the ion exchange reaction is stirred at 50-70℃ for 8-16 hours; after the reaction is completed, the filler is centrifuged, washed, and dried to obtain the organic-inorganic hybrid layered filler of the intercalated repair agent monomer.

10. A method for preparing ink for photovoltaic modules according to claim 6, characterized in that, In step S3, the curing initiator is a compound system of photoinitiator and thermal initiator, and the weight ratio of photoinitiator to thermal initiator is 1.5:1 to 10:

1. The photoinitiator is 2-hydroxy-2-methyl-1-phenylpropanone or 1-hydroxycyclohexylphenyl ketone; the thermal initiator is benzoyl peroxide or azobisisobutyronitrile; and it is added after the filler pre-dispersion slurry and resin base solution have been dispersed at high speed.

Images