Preparation method of composite film on glass surface of solar photovoltaic module

Abstract

The invention relates to a preparation method of a solar photovoltaic module glass surface composite film, and belongs to the technical field of photovoltaic modules. The preparation method comprises the following steps: by taking PMMA as a film forming material, introducing a fluorosilicone enhancer for mixing modification, carrying out substitution reaction on brominated undecene and octafluoro-1, 6-hexanediol, introducing an undecene structure to two molecular ends of the octafluoro-1, 6-hexanediol, and carrying out hydrosilylation with dodecamethyldihydrohexasiloxane, so as to prepare a chain polymer with low molecular weight; the fluorosilicone enhancer has a fluorine chain segment, alkyl chain segment and silicon-oxygen chain block structure, has good compatibility with a PMMA matrix, forms a continuous gradient low-refraction structure in PMMA macromolecules, increases the overall light transmittance, reinforces the film layer through dipole-dipole interaction and microscopic non-uniform entanglement of molecular chains, and increases the scratch resistance of the film layer.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic modules, and in particular relates to a method for preparing a composite film on the surface of glass of a solar photovoltaic module. Background Art

[0002] In the development of functionalized thin films for solar photovoltaic module glass surfaces, polymethyl methacrylate (PMMA) is often chosen as the film-forming substrate due to its excellent light transmittance, ease of processing, and low cost. However, PMMA has the following limitations in practical applications: insufficient mechanical strength and susceptibility to scratching by external forces such as sand, gravel, and hail in outdoor environments, which leads to increased surface light scattering and significant transmittance reduction; and PMMA's high refractive index results in significant interfacial reflection losses when directly coated on glass surfaces.

[0003] In the field of functionalized films on the surface of solar photovoltaic module glass, in order to improve light transmittance and take into account surface protection performance, the existing technology often adopts two types of solutions: First, the use of fluorine-containing compounds for modification, by introducing fluorides to reduce the refractive index of the film to improve light transmittance; however, fluorides have poor compatibility with the matrix material, which can easily lead to weakening of the interfacial bonding force, and the low surface energy characteristics of the fluorine segment will significantly reduce the mechanical strength of the film, resulting in a decrease in scratch resistance, making it difficult to meet the needs of long-term outdoor use. Second, the use of inorganic fillers for reinforcement, such as adding nanoparticles such as silica to increase the hardness of the film, but there is a large difference in the refractive index of the inorganic filler and the organic matrix, forming a large number of uneven interfaces, resulting in a loss of light transmittance. In addition, excessive fillers will destroy the continuity of the film and reduce the adhesion of the film layer. In the existing technology, there is a significant contradiction in the synergistic improvement of light transmittance and scratch resistance. Summary of the Invention

[0004] In order to solve the technical problems mentioned in the background technology, the purpose of the present invention is to provide a method for preparing a composite film on the surface of solar photovoltaic module glass.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for preparing a composite film on the surface of solar photovoltaic module glass comprises the following steps: premixing PMMA resin, a fluorosilicone reinforcing agent, and a composite solvent; adding a leveling agent, mixing, and vacuum degassing to form a casting liquid; then coating the casting liquid on the surface of the photovoltaic glass; and forming the composite film through stepwise curing.

[0007] The preparation method of fluorosilicone reinforcing agent is as follows:

[0008] Step A1: octafluoro-1,6-hexanediol and dimethyl sulfoxide are mixed, undecene bromide and N,N-diisopropylethylamine are added, nitrogen is introduced, stirring is applied at 120-150 rpm, the temperature is raised to 100-120°C, and the reaction is carried out for 1.3-1.8 hours. After the reaction is completed, the dimethyl sulfoxide is evaporated under reduced pressure to obtain a fluoromonomer;

[0009] Furthermore, the feed ratio of octafluoro-1,6-hexanediol, brominated undecene, N,N-diisopropylethylamine, and dimethyl sulfoxide is 10 mmol:20 mmol:10-15 mL:30-40 mL. N,N-diisopropylethylamine is used as an acid-binding agent to promote the substitution reaction of brominated undecene with octafluoro-1,6-hexanediol, thereby introducing an undecene structure into both ends of the octafluoro-1,6-hexanediol molecule. The specific reaction route is as follows:

[0010]

[0011] Step A2: dodecamethyldihydrogen hexasiloxane, fluorine monomer and dimethylformamide are mixed, platinum carbon catalyst is added, the mixture is pressurized to 2-3 bar with nitrogen, the temperature is raised to 130-150°C and the mixture is kept for reaction for 6-7.5 hours. After the reaction is completed, water is added to wash the mixture, the water phase is removed and dried to obtain a fluorosilicone reinforcing agent;

[0012] Furthermore, the feed ratio of dodecamethyldihydrogen hexasiloxane, fluorine monomer, platinum carbon catalyst and dimethylformamide is 10mmol:10mmol:35-50mg:60-90mL. Under the catalysis of the platinum carbon catalyst, dodecamethyldihydrogen hexasiloxane and the fluorine monomer undergo a hydrosilylation reaction to produce a low molecular weight chain polymer. The specific reaction route is as follows:

[0013]

[0014] Furthermore, the content of PMMA resin in the casting solution is 25-32 wt %, and the content of fluorosilicone reinforcing agent is 5-8.5 wt %.

[0015] Furthermore, the photovoltaic glass surface is activated before coating, specifically: the surface is ultrasonically cleaned with ethanol and deionized water, and then plasma treated in a nitrogen environment until the surface energy is not less than 40mN / m.

[0016] Furthermore, the coating process of the casting solution is doctor blade coating, and the thickness of the composite film is 100-150 μm.

[0017] Furthermore, the composite solvent is prepared by compounding acetone, tetrahydrofuran and ethyl acetate.

[0018] Furthermore, the step-by-step curing process parameters are: pre-curing: temperature 45-60°C, curing time 20-30 minutes; final curing: temperature 80-100°C, curing time 1.2-1.6 hours; annealing: temperature 110-120°C, processing time 10-15 minutes.

[0019] Beneficial effects of the present invention:

[0020] The present invention adopts a coating method to prepare a composite film for the glass surface of a photovoltaic module, uses PMMA as a film-forming material, and introduces a fluorosilicone enhancer to improve the light transmittance and scratch resistance of the existing film layer. The fluorosilicone enhancer is prepared by a substitution reaction between brominated undecene and octafluoro-1,6-hexanediol, introducing an undecene structure into both ends of the octafluoro-1,6-hexanediol molecule, and then undergoing a silylation reaction with dodecamethyldihydrogen hexasiloxane to prepare a chain polymer with a low molecular weight, namely the fluorosilicone enhancer. Compared with the existing technology, the fluorosilicone enhancer has the following advantages: 1. The alkyl segment of the fluorosilicone enhancer is largely separated from PMMA. 1. The compatibility of the sub-main chains is high, which reduces the light scattering caused by phase separation, and the fluorine segments are dispersed in the PMMA macromolecules to form a continuous gradient low-refractive structure, increasing the overall light transmittance; 2. The Si-O polar bonds in the silicon oxide segments produce strong dipole-dipole interactions with the ester groups in the side chains of the PMMA molecules, weakening the segregation tendency of the fluorine segments and improving the scratch resistance of the film layer; 3. The fluorine segments, alkyl segments, and silicon oxide segments of the fluorosilicone enhancer form a gradient interfacial tension, forming a microscopic non-uniform entanglement of the molecular chains, further reducing the segregation of the fluorine structure, and strengthening the film layer in terms of microstructure. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0022] Example 1: Preparation of a composite film for the glass surface of a solar photovoltaic module. The specific implementation method is as follows:

[0023] 1. Synthetic fluorosilicone reinforcing agent

[0024] a1. Preparation of fluoromonomer: octafluoro-1,6-hexanediol and dimethyl sulfoxide were added and stirred to dissolve, and then undecene bromide and N,N-diisopropylethylamine were added. Nitrogen protection was introduced and stirred at 120 rpm. The temperature was raised to 100°C and the reaction was carried out for 1.8 hours. After the reaction was completed, the dimethyl sulfoxide was evaporated under reduced pressure to obtain a fluoromonomer. As in the above reaction, the feed ratio of octafluoro-1,6-hexanediol, undecene bromide, N,N-diisopropylethylamine and dimethyl sulfoxide was 10 mmol:20 mmol:10 mL:30 mL.

[0025] a2. Preparation of fluorosilicone enhancer: dodecamethyldihydrogen hexasiloxane, fluorine monomer and dimethylformamide were mixed, a platinum carbon catalyst was added, the mixture was pressurized to 2 bar with nitrogen, the temperature was raised to 130°C and the mixture was kept for reaction for 7.5 hours. After the reaction was completed, water was added to wash the mixture, the aqueous phase was removed and dried to obtain a fluorosilicone enhancer. In the above reaction, the platinum carbon catalyst was a commercially available product of type HiCaP40, and the feed ratio of dodecamethyldihydrogen hexasiloxane, fluorine monomer, platinum carbon catalyst and dimethylformamide was 10 mmol:10 mmol:35 mg:60 mL.

[0026] 2. Preparation of composite films

[0027] s1. Preparation of casting liquid: Ingredients are prepared according to weight percentage: 32wt% of PMMA resin, PLEXIGLAS 8N resin raw material, 5wt% of fluorosilicone reinforcing agent, prepared in this embodiment; 0.8wt% of leveling agent, AKN-1377 commercially available raw material; the remainder is a composite solvent, which is premixed and compounded with acetone, tetrahydrofuran and ethyl acetate in a volume ratio of 1:0.8:0.2; PMMA resin, fluorosilicone reinforcing agent and composite solvent are premixed, the leveling agent is added and mixed, and vacuum degassing is performed to prepare a casting liquid.

[0028] s2. Coating curing: Take photovoltaic glass, ultrasonically clean the surface with ethanol and deionized water, perform plasma treatment in a nitrogen environment, and detect the surface energy to reach 40mN to meet the standard. Then, apply the casting liquid to the surface of the photovoltaic glass by blade coating. During the implementation process, the coating is carried out according to the set dry film thickness of 120μm. After that, it is sent to the curing furnace and a step-by-step curing process is adopted. The process parameters are set as follows: pre-curing: temperature 45℃, curing time 30min; final curing: temperature 100℃, curing time 1.2h; annealing: temperature 120℃, treatment time 10min, to form a composite film on the surface of the photovoltaic glass.

[0029] Example 2, preparation of a composite film for the glass surface of a solar photovoltaic module, the specific implementation method is as follows:

[0030] 1. Synthetic fluorosilicone reinforcing agent

[0031] a1. Preparation of fluoromonomer: octafluoro-1,6-hexanediol and dimethyl sulfoxide were added and stirred to dissolve, and then undecene bromide and N,N-diisopropylethylamine were added. Nitrogen protection was introduced and stirred at 150 rpm. The temperature was raised to 120°C and the reaction was carried out for 1.3 hours. After the reaction was completed, the dimethyl sulfoxide was evaporated under reduced pressure to obtain a fluoromonomer. As in the above reaction, the feed ratio of octafluoro-1,6-hexanediol, undecene bromide, N,N-diisopropylethylamine and dimethyl sulfoxide was 10 mmol:20 mmol:15 mL:40 mL.

[0032] a2. Preparation of fluorosilicone enhancer: dodecamethyldihydrogen hexasiloxane, fluorine monomer and dimethylformamide were mixed, a platinum carbon catalyst was added, the mixture was pressurized to 3 bar with nitrogen, the temperature was raised to 150°C and the mixture was kept for reaction for 6 hours. After the reaction was completed, water was added to wash the mixture, the aqueous phase was removed and dried to obtain a fluorosilicone enhancer. In the above reaction, the platinum carbon catalyst was a commercially available product of type HiCaP40, and the feed ratio of dodecamethyldihydrogen hexasiloxane, fluorine monomer, platinum carbon catalyst and dimethylformamide was 10 mmol:10 mmol:50 mg:90 mL.

[0033] 2. Preparation of composite films

[0034] s1. Preparation of casting liquid: Ingredients are prepared according to weight percentage: 25wt% of PMMA resin, PLEXIGLAS 8N resin raw material, 8.5wt% of fluorosilicone reinforcing agent, prepared in this embodiment; 0.6wt% of leveling agent, AKN-1377 commercially available raw material; the remainder is a composite solvent, which is premixed and compounded with acetone, tetrahydrofuran and ethyl acetate in a volume ratio of 1:0.5:0.4; PMMA resin, fluorosilicone reinforcing agent and composite solvent are premixed, the leveling agent is added and mixed, and vacuum degassing is performed to prepare a casting liquid.

[0035] s2. Coating curing: Take photovoltaic glass, ultrasonically clean the surface with ethanol and deionized water, perform plasma treatment in a nitrogen environment, and detect that the surface energy reaches 40mN, then apply the casting liquid to the surface of the photovoltaic glass by blade coating, and then send it into the curing furnace. A step-by-step curing process is adopted, and the process parameters are set as follows: pre-curing: temperature 60°C, curing time 20min; final curing: temperature 80°C, curing time 1.6h; annealing: temperature 110°C, treatment time 15min, to form a composite film on the surface of the photovoltaic glass.

[0036] Example 3, preparation of a composite film for the glass surface of a solar photovoltaic module, the specific implementation method is as follows:

[0037] 1. Synthetic fluorosilicone reinforcing agent

[0038] a1. Preparation of fluoromonomer: octafluoro-1,6-hexanediol and dimethyl sulfoxide were added and stirred to dissolve, and then undecene bromide and N,N-diisopropylethylamine were added. Nitrogen protection was introduced and stirred at 120 rpm. The temperature was raised to 110°C and the reaction was carried out for 1.5 hours. After the reaction was completed, the dimethyl sulfoxide was evaporated under reduced pressure to obtain a fluoromonomer. As in the above reaction, the charging ratio of octafluoro-1,6-hexanediol, undecene bromide, N,N-diisopropylethylamine and dimethyl sulfoxide was 10 mmol:20 mmol:12 mL:35 mL.

[0039] a2. Preparation of fluorosilicone enhancer: dodecamethyldihydrogen hexasiloxane, fluorine monomer and dimethylformamide were mixed, a platinum carbon catalyst was added, the mixture was pressurized to 2.5 bar with nitrogen, the temperature was raised to 140°C and the mixture was kept for reaction for 7 hours. After the reaction was completed, water was added to wash the mixture, the aqueous phase was removed and dried to obtain a fluorosilicone enhancer. In the above reaction, the platinum carbon catalyst was a commercially available product of type HiCaP40, and the feed ratio of dodecamethyldihydrogen hexasiloxane, fluorine monomer, platinum carbon catalyst and dimethylformamide was 10 mmol:10 mmol:40 mg:80 mL.

[0040] 2. Preparation of composite films

[0041] s1. Preparation of casting liquid: Ingredients are prepared according to weight percentage: 30wt% of PMMA resin, PLEXIGLAS 8N type resin raw material, 6.8wt% of fluorosilicone reinforcing agent, prepared in this embodiment; 0.7wt% of leveling agent, AKN-1377 type commercially available raw material; the remainder is a composite solvent, which is premixed and compounded with acetone, tetrahydrofuran and ethyl acetate in a volume ratio of 1:0.6:0.3; PMMA resin, fluorosilicone reinforcing agent and composite solvent are premixed, the leveling agent is added and mixed, and vacuum degassing is performed to prepare a casting liquid.

[0042] s2. Coating curing: Take photovoltaic glass, ultrasonically clean the surface with ethanol and deionized water, perform plasma treatment in a nitrogen environment, and detect the surface energy to reach 40mN to meet the standard. Then apply the casting liquid to the surface of the photovoltaic glass by blade coating, and then send it into the curing furnace. A step-by-step curing process is adopted. The process parameters are set as follows: pre-curing: temperature 50℃, curing time 28min; final curing: temperature 90℃, curing time 1.5h; annealing: temperature 110℃, treatment time 15min, to form a composite film on the surface of the photovoltaic glass.

[0043] Example 4, preparation of a composite film for the glass surface of a solar photovoltaic module, the specific implementation method is as follows:

[0044] 1. Synthetic fluorosilicone reinforcing agent

[0045] a1. Preparation of fluoromonomer: octafluoro-1,6-hexanediol and dimethyl sulfoxide were added and stirred to dissolve, and then undecene bromide and N,N-diisopropylethylamine were added. Nitrogen protection was introduced and stirred at 150 rpm. The temperature was raised to 110°C and the reaction was carried out for 1.6 hours. After the reaction was completed, the dimethyl sulfoxide was evaporated under reduced pressure to obtain a fluoromonomer. As in the above reaction, the charging ratio of octafluoro-1,6-hexanediol, undecene bromide, N,N-diisopropylethylamine and dimethyl sulfoxide was 10 mmol:20 mmol:12 mL:30 mL.

[0046] a2. Preparation of fluorosilicone enhancer: dodecamethyldihydrogen hexasiloxane, fluorine monomer and dimethylformamide were mixed, a platinum carbon catalyst was added, the mixture was pressurized to 3 bar with nitrogen, the temperature was raised to 140°C and the mixture was kept for reaction for 6.5 hours. After the reaction was completed, water was added to wash the mixture, the aqueous phase was removed and dried to obtain a fluorosilicone enhancer. In the above reaction, the platinum carbon catalyst was a commercially available product of type HiCaP40, and the feed ratio of dodecamethyldihydrogen hexasiloxane, fluorine monomer, platinum carbon catalyst and dimethylformamide was 10 mmol:10 mmol:45 mg:80 mL.

[0047] 2. Preparation of composite films

[0048] s1. Preparation of casting liquid: Ingredients are prepared according to weight percentage: 28wt% of PMMA resin, PLEXIGLAS 8N type resin raw material, 7.2wt% of fluorosilicone reinforcing agent, prepared in this embodiment; 0.7wt% of leveling agent, AKN-1377 type commercially available raw material; the remainder is a composite solvent, which is premixed and compounded with acetone, tetrahydrofuran and ethyl acetate in a volume ratio of 1:0.7:0.3; PMMA resin, fluorosilicone reinforcing agent and composite solvent are premixed, the leveling agent is added and mixed, and vacuum degassing is performed to prepare a casting liquid.

[0049] s2. Coating curing: Take photovoltaic glass, ultrasonically clean the surface with ethanol and deionized water, perform plasma treatment in a nitrogen environment, and detect the surface energy to reach 40mN, then apply the casting liquid to the surface of the photovoltaic glass by blade coating, and then send it into the curing furnace. A step-by-step curing process is adopted, and the process parameters are set as follows: pre-curing: temperature 55°C, curing time 25min; final curing: temperature 100°C, curing time 1.4h; annealing: temperature 110°C, treatment time 15min, to form a composite film on the surface of the photovoltaic glass.

[0050] Comparative Example 1, referring to Example 4, the fluorosilicone reinforcing agent was replaced with RF-902 commercially available fluorosilicone resin, and the rest of the implementation process was exactly the same.

[0051] Comparative Example 2, referring to the prior art, the fluorosilicone reinforcing agent was replaced with 6 wt % of nano-silica and 1.2 wt % of tridecafluorooctyltrimethoxysilane, and the rest of the implementation process was exactly the same.

[0052] The samples prepared above were tested for adhesion according to ASTM D3359-23, transmittance according to GB / T 2410-2008, scratch resistance pencil hardness according to ASTM D3363-22, and water contact angle according to ASTM D7334-08. The specific test results are shown in Table 1:

[0053] Table 1

[0054]

[0055]

[0056] It can be seen from the test results in Table 1 that the composite film prepared in the embodiment has good bonding strength with the photovoltaic glass, high light transmittance, good scratch resistance of the film layer, and a certain anti-fouling and self-cleaning effect.

[0057] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0058] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a composite film on the surface of a solar photovoltaic module glass, characterized in that: Specifically, PMMA resin, fluorosilicone reinforcing agent and composite solvent are premixed, a leveling agent is added and mixed evenly, and vacuum degassing is performed to prepare a casting solution, which is then coated on the surface of photovoltaic glass and cured in a stepwise manner to form a composite film. Step A1: octafluoro-1,6-hexanediol and dimethyl sulfoxide are mixed, undecene bromide and N,N-diisopropylethylamine are added, nitrogen is introduced, and the mixture is stirred and heated to 100-120°C for reaction for 1.3-1.8 hours. After the reaction is completed, dimethyl sulfoxide is evaporated under reduced pressure to obtain a fluoromonomer; Step A2: dodecamethyldihydrogen hexasiloxane, fluorine monomer and dimethylformamide are mixed, a platinum carbon catalyst is added, the mixture is pressurized to 2-3 bar with nitrogen, the temperature is raised to 130-150°C and the mixture is kept in the reaction for 6-7.5 hours. After the reaction is completed, water is added to wash the mixture, the water phase is removed and dried to obtain a fluorosilicone enhancer.

2. The method for preparing a composite film on the surface of a solar photovoltaic module glass according to claim 1, characterized in that: The feeding ratio of octafluoro-1,6-hexanediol, undecene bromide, N,N-diisopropylethylamine and dimethyl sulfoxide is 10 mmol: 20 mmol: 10-15 mL: 30-40 mL.

3. The method for preparing a composite film on the surface of a solar photovoltaic module glass according to claim 2, characterized in that: The feed ratio of dodecamethyldihydrogen hexasiloxane, fluorine monomer, platinum carbon catalyst and dimethylformamide is 10 mmol: 10 mmol: 35-50 mg: 60-90 mL.

4. The method for preparing a composite film on the surface of a solar photovoltaic module glass according to claim 3, characterized in that: The content of PMMA resin in the casting solution is 25-32 wt%, and the content of fluorosilicone reinforcing agent is 5-8.5 wt%.

5. The method for preparing a composite film on the surface of a solar photovoltaic module glass according to claim 1, characterized in that: The photovoltaic glass surface is activated before coating, and the surface energy after treatment is not less than 40mN / m.

6. The method for preparing a composite film on the surface of a solar photovoltaic module glass according to claim 1, characterized in that: The coating process of the casting solution is doctor blade coating, and the thickness of the composite film is 100-150 μm.

7. The method for preparing a composite film on the surface of a solar photovoltaic module glass according to claim 1, characterized in that: The composite solvent is prepared by mixing acetone, tetrahydrofuran and ethyl acetate.

8. The method for preparing a composite film on the surface of solar photovoltaic module glass according to claim 1, characterized in that: The step-by-step curing process parameters are: pre-curing: temperature 45-60°C, curing time 20-30 minutes; final curing: temperature 80-100°C, curing time 1.2-1.6 hours; annealing: temperature 110-120°C, processing time 10-15 minutes.

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