High weather-resistant coating for black backboard of photovoltaic module and preparation method thereof

Abstract

This application relates to the field of coatings, specifically disclosing a high-weather-resistant coating for black backsheets of photovoltaic modules and its preparation method. The high-weather-resistant coating for black backsheets of photovoltaic modules, by weight, comprises 100-120 parts of fluorocarbon resin, 50-100 parts of acrylic resin, 20-40 parts of fluorinated graphene, 5-30 parts of toughening agent, 10-30 parts of curing agent, and 100-200 parts of solvent. The preparation method is as follows: fluorinated graphene is placed in a solvent and ultrasonically treated for 10-20 minutes to obtain a dispersion; the fluorocarbon resin, acrylic resin, toughening agent, and curing agent are added to the dispersion and stirred evenly to obtain a mixed coating; the mixed coating is stirred in a vacuum environment to remove air bubbles and allowed to stand to obtain the high-weather-resistant coating for black backsheets of photovoltaic modules. The high-weather-resistant coating for black backsheets of photovoltaic modules of this application has the advantage of improved weather resistance.

Description

Technical Field

[0001] This application relates to the field of coatings, and more specifically, to a high weather-resistant coating for a black backsheet of photovoltaic modules and a method for its preparation. Background Technology

[0002] A photovoltaic (PV) module is a minimal, indivisible assembly of integrated photovoltaic cells, capable of providing direct current (DC) output independently. The core component of a PV module, the photovoltaic cell, has a limited power output per cell and must be connected in series and packaged into a module to function as a power source. Typically, the photovoltaic cell is encapsulated between the front glass (sunlight-receiving side) and a backsheet (PV panel) on the back, sealed with EVA adhesive. To ensure the module's lifespan, the backsheet requires good weather resistance and a high degree of sealing with the EVA adhesive layer.

[0003] Integrated black modules are gaining popularity, and black photovoltaic backsheets are becoming increasingly widely used. Black solar cell backsheets are primarily used in distributed power stations, achieving a color matching the black crystalline silicon cells and black borders. The backsheet's color is aesthetically pleasing and can coordinate with buildings, while also ensuring the mechanical strength of the solar panel and preventing moisture penetration into the sealing layer, which could affect the cell's lifespan and power generation efficiency.

[0004] Because black photovoltaic modules have a greater heat absorption effect than other colored modules, stricter requirements are placed on the weather resistance of black backsheets in practical applications. They need not only good resistance to environmental corrosion and electrical insulation, and resistance to damp heat aging, but also high temperature resistance and UV protection. Currently, coatings used for photovoltaic backsheets have not addressed the shortcomings of black backsheets, and their poor weather resistance remains a problem during use. Summary of the Invention

[0005] To improve the weather resistance of photovoltaic backsheet coatings, this application provides a high weather-resistant coating for black backsheets of photovoltaic modules and a method for its preparation.

[0006] Firstly, the high weather-resistant coating for black backsheets of photovoltaic modules provided in this application adopts the following technical solution:

[0007] A high weather-resistant coating for black backsheets of photovoltaic modules, comprising, by weight, 100-120 parts of fluorocarbon resin, 50-100 parts of acrylic resin, 20-40 parts of fluorinated graphene, 5-30 parts of toughening agent, 10-30 parts of curing agent, and 100-200 parts of solvent.

[0008] By adopting the above technical solutions, the use of fluorocarbon resin provides excellent weather resistance and chemical resistance, offering protection against environmental erosion for photovoltaic backsheet coatings while also providing good electrical insulation. Acrylic resin exhibits high weather resistance and chemical stability, enhancing the coating's weather resistance. The longer carbon chains in the side chains of the acrylic resin blended with fluorocarbon resin enhance the molecular chain entanglement with EVA resin, improving adhesion. Furthermore, the abundance of ester groups in the acrylic resin backbone improves its adhesion to polyester-based films. Fluorinated graphene absorbs and scatters ultraviolet light, improving the coating's UV resistance; its high-temperature stability allows the coating to maintain stable performance under high-temperature conditions; simultaneously, the barrier properties and interfacial reinforcement of fluorinated graphene reduce the penetration of external corrosive substances, improve the coating's durability and mechanical strength, protect it from environmental erosion and aging, and extend its service life.

[0009] Optionally, by weight, it includes 110 parts of fluorocarbon resin, 66 parts of acrylic resin, 32 parts of fluorinated graphene, 15 parts of toughening agent, 18 parts of curing agent, and 175 parts of solvent.

[0010] By adopting the above technical solution, this ratio is the optimal solution in this application.

[0011] Optionally, the preparation method of the fluorinated graphene is as follows:

[0012] A1. Place graphite powder in an ethanol solution and ultrasonically disperse it for 5-10 min, then perform high-speed mechanical shearing and stirring at a speed of 1000-1200 r / min for 8-10 h. After stirring, centrifuge at 5000-6000 r / min for 5-10 min, and place the bottom precipitate in a vacuum drying oven at 50-70℃ for 10-12 h to obtain graphene powder.

[0013] A2. Hydrofluoric acid and N-methylpyrrolidone are mixed at a mass ratio of 1:(2-4) to obtain a fluorinating agent ionic liquid. Graphene powder is placed in the fluorinating agent ionic liquid for reaction. The mass ratio of graphene powder to fluorinating agent ionic liquid is 1:(1-2). The reaction time is 6-10 h and the temperature is 60-80℃ to obtain fluorinated graphene.

[0014] A3. After the reaction is complete, the fluorinated graphene is washed with acetone and then dried to obtain clean fluorinated graphene.

[0015] By employing the above technical solution, the high-speed rotation of the rotor in the mixing head generates a strong suction force during the rotation process, drawing liquid and solid substances from the bottom of the container upwards to the center of the mixing head. Then, centrifugal force carries the material to the periphery of the mixing head, where the strong shear force generated at high speed causes the graphite sheets to peel off, yielding graphene. Hydrofluoric acid and N-methylpyrrolidone are used as fluorinating ionic liquids to react with the graphite powder, achieving the fluorination of graphene. The hydrofluoric acid in the fluorinating ionic liquid can react with the hydroxyl or oxygen functional groups on the graphite surface to form CF bonds, thus realizing the preparation of fluorinated graphene.

[0016] Optionally, the weight ratio of the fluorocarbon resin and the acrylic resin is 1:(0.5-0.8).

[0017] By adopting the above technical solution, fluorocarbon resin and acrylic resin are mixed in a weight ratio of 1:(0.5-0.8), which can improve the weather resistance, chemical stability, and mechanical strength of the coating, and give the coating surface good gloss and smoothness. This ratio makes the coating more suitable for the requirements of black backsheets, improving the performance and durability of photovoltaic backsheet coatings.

[0018] Optionally, the toughening agent comprises 10-30% polyester polyol and 70-90% polyaspartic acid ester.

[0019] By adopting the above technical solutions, polyester polyols possess excellent flexibility and toughness, which can increase the ductility and impact resistance of coatings. Polyaspartic acid esters are also excellent toughening agents, providing high flexural strength and abrasion resistance. By mixing these two toughening agents in an appropriate ratio, their advantages can be combined to significantly improve the toughness and adhesion of the coating without affecting its weather resistance. A reasonable ratio allows the coating to be more evenly distributed on the coating surface, reducing coating defects and unevenness.

[0020] Optionally, the curing agent includes one or more of isocyanate, amino resin and melamine.

[0021] Optionally, the solvent includes one or more of toluene, xylene, ethyl acetate, and butyl acetate.

[0022] Secondly, this application provides a method for preparing a high weather-resistant coating for a black backsheet of photovoltaic modules, using the following technical solution:

[0023] A method for preparing a high weather-resistant coating for a black backsheet of photovoltaic modules includes the following steps:

[0024] S1. Place fluorinated graphene in a solvent and sonicate for 10-20 min to obtain a dispersion.

[0025] S2. Add fluorocarbon resin, acrylic resin, toughening agent and curing agent to the dispersion and stir for 5-10 minutes to mix evenly to obtain a mixed coating;

[0026] S3. Stir the mixed coating in a vacuum environment to remove air bubbles and let it stand for 5-15 minutes to obtain a high weather-resistant coating for black backsheets of photovoltaic cell modules.

[0027] By employing the above technical solution, fluorinated graphene particles can be effectively dispersed and uniformly dispersed in the solution through ultrasonic treatment in a solvent. This helps improve the uniformity and stability of the coating while maintaining the excellent properties of graphene. Stirring and mixing the coating in a vacuum environment effectively removes air bubbles, ensuring coating quality. The settling process further helps to allow air bubbles inside the coating to rise and dissipate, improving the coating's density and smoothness.

[0028] In summary, this application has the following beneficial effects:

[0029] 1. This application utilizes fluorocarbon resin, which possesses excellent weather resistance and chemical resistance, providing protection against environmental erosion for photovoltaic backsheet coatings while also exhibiting good electrical insulation. Acrylic resin has high weather resistance and chemical stability, enhancing the coating's weather resistance. The acrylic resin blended with fluorocarbon resin contains longer carbon chains in its side chains, which enhances the molecular chain entanglement with EVA resin and improves adhesion. Furthermore, the acrylic resin backbone has numerous ester groups, which is beneficial for improving its adhesion to polyester-based films. Fluorinated graphene has the ability to absorb and scatter ultraviolet light, improving the coating's resistance to ultraviolet radiation; its high-temperature stability allows the coating to maintain stable performance under high-temperature conditions; simultaneously, the barrier properties and interfacial reinforcement of fluorinated graphene can reduce the penetration of external corrosive substances, improve the coating's durability and mechanical strength, protect the coating from environmental erosion and aging, and extend the coating's service life.

[0030] 2. In this application, a preferred method is to utilize the high-speed rotation of the rotor in the mixing head during rotation to generate strong suction, drawing liquid and solid substances from the bottom of the container upwards to the center of the mixing head. Then, centrifugal force carries the material to the periphery of the mixing head, where the strong shear force generated at high speed causes the graphite sheets to peel off, yielding graphene. Hydrofluoric acid and N-methylpyrrolidone are used as fluorinating ionic liquids to react with the graphite powder, achieving the fluorination of the graphene. The hydrofluoric acid in the fluorinating ionic liquid can react with the hydroxyl or oxygen functional groups on the graphite surface to form CF bonds, thus preparing fluorinated graphene. This preparation method is simple and easy to operate, and the obtained fluorinated graphene has high purity.

[0031] 3. This application utilizes the excellent flexibility and toughness of polyester polyols, which can increase the ductility and impact resistance of the coating. Polyaspartic acid ester is also an excellent toughening agent, providing high flexural strength and abrasion resistance. By mixing these two toughening agents in an appropriate ratio, their advantages can be combined to significantly improve the toughness and adhesion of the coating without affecting its weather resistance. A reasonable ratio can make the coating more evenly distributed on the coating surface, reducing coating defects and unevenness. Detailed Implementation

[0032] The present application will be further described in detail below with reference to embodiments, but is not limited thereto.

[0033] Preparation example of fluorinated graphene

[0034] Preparation Example 1

[0035] The preparation method of fluorinated graphene is as follows:

[0036] A1. Add 5 kg of graphite powder to 8 kg of ethanol solution. Use an ultrasonic vibrator to ultrasonically disperse the ethanol solution for 8 min. Then, use a stirrer to mechanically stir the ethanol solution at high speed with a speed of 1100 r / min for 9 h. After stirring, transfer the mixture of graphite and ethanol to a centrifuge and centrifuge at 5500 r / min for 8 min. After centrifugation, remove the supernatant and place the bottom precipitate in a vacuum drying oven at 60°C for 10 h to obtain graphene powder.

[0037] A2. Mix 1.5 kg of hydrofluoric acid and 6 kg of N-methylpyrrolidone and stir evenly to obtain a fluorinating agent ionic liquid. Place graphene powder in the fluorinating agent ionic liquid for reaction. The graphene powder and fluorinating agent ionic liquid are added at a mass ratio of 1:1.5. The reaction time is 8 hours and the temperature is maintained at 70℃. After the reaction is completed, solid-liquid separation is performed, and the collected solid is fluorinated graphene.

[0038] A3. Fluorinated graphene is washed with sufficient acetone to remove residual liquid and impurities, and then dried to obtain clean fluorinated graphene.

[0039] Preparation Example 2

[0040] The preparation method of fluorinated graphene is as follows:

[0041] A1. Add 5 kg of graphite powder to 8 kg of ethanol solution. Use an ultrasonic vibrator to ultrasonically disperse the ethanol solution for 8 min. Then, use a stirrer to mechanically stir the ethanol solution at high speed with a speed of 1100 r / min for 9 h. After stirring, transfer the mixture of graphite and ethanol to a centrifuge and centrifuge at 5500 r / min for 8 min. After centrifugation, remove the supernatant and place the bottom precipitate in a vacuum drying oven at 60°C for 10 h to obtain graphene powder.

[0042] A2. Mix 2.5 kg of hydrofluoric acid and 5 kg of N-methylpyrrolidone and stir evenly to obtain a fluorinating agent ionic liquid. Place graphene powder in the fluorinating agent ionic liquid for reaction. The graphene powder and fluorinating agent ionic liquid are added at a mass ratio of 1:1.5. The reaction time is 8 hours and the temperature is maintained at 70℃. After the reaction is completed, solid-liquid separation is performed, and the collected solid is fluorinated graphene.

[0043] A3. Fluorinated graphene is washed with sufficient acetone to remove residual liquid and impurities, and then dried to obtain clean fluorinated graphene.

[0044] Preparation Example 3

[0045] The preparation method of fluorinated graphene is as follows:

[0046] A1. Add 5 kg of graphite powder to 8 kg of ethanol solution. Use an ultrasonic vibrator to ultrasonically disperse the ethanol solution for 8 min. Then, use a stirrer to mechanically stir the ethanol solution at high speed with a speed of 1100 r / min for 9 h. After stirring, transfer the mixture of graphite and ethanol to a centrifuge and centrifuge at 5500 r / min for 8 min. After centrifugation, remove the supernatant and place the bottom precipitate in a vacuum drying oven at 60°C for 10 h to obtain graphene powder.

[0047] A2. Mix 1.88 kg of hydrofluoric acid and 5.62 kg of N-methylpyrrolidone and stir evenly to obtain a fluorinating agent ionic liquid. Place graphene powder in the fluorinating agent ionic liquid for reaction. The graphene powder and fluorinating agent ionic liquid are added at a mass ratio of 1:1.5. The reaction time is 8 hours and the temperature is maintained at 70℃. After the reaction is completed, solid-liquid separation is performed, and the collected solid is fluorinated graphene.

[0048] A3. Fluorinated graphene is washed with sufficient acetone to remove residual liquid and impurities, and then dried to obtain clean fluorinated graphene.

[0049] Preparation Example 4

[0050] The preparation method of fluorinated graphene is as follows:

[0051] A1. Add 5 kg of graphite powder to 8 kg of ethanol solution. Use an ultrasonic vibrator to ultrasonically disperse the ethanol solution for 8 min. Then, use a stirrer to mechanically stir the ethanol solution at high speed with a speed of 1100 r / min for 9 h. After stirring, transfer the mixture of graphite and ethanol to a centrifuge and centrifuge at 5500 r / min for 8 min. After centrifugation, remove the supernatant and place the bottom precipitate in a vacuum drying oven at 60°C for 10 h to obtain graphene powder.

[0052] A2. Mix 1.25 kg of hydrofluoric acid and 3.75 kg of N-methylpyrrolidone and stir evenly to obtain a fluorinating agent ionic liquid. Place graphene powder in the fluorinating agent ionic liquid for reaction. The graphene powder and the fluorinating agent ionic liquid are added at a mass ratio of 1:1. The reaction time is 8 hours and the temperature is maintained at 70℃. After the reaction is completed, solid-liquid separation is performed, and the collected solid is fluorinated graphene.

[0053] A3. Fluorinated graphene is washed with sufficient acetone to remove residual liquid and impurities, and then dried to obtain clean fluorinated graphene.

[0054] Preparation Example 5

[0055] The preparation method of fluorinated graphene is as follows:

[0056] A1. Add 5 kg of graphite powder to 8 kg of ethanol solution. Use an ultrasonic vibrator to ultrasonically disperse the ethanol solution for 8 min. Then, use a stirrer to mechanically stir the ethanol solution at high speed with a speed of 1100 r / min for 9 h. After stirring, transfer the mixture of graphite and ethanol to a centrifuge and centrifuge at 5500 r / min for 8 min. After centrifugation, remove the supernatant and place the bottom precipitate in a vacuum drying oven at 60°C for 10 h to obtain graphene powder.

[0057] A2. Mix 2.5 kg of hydrofluoric acid and 7.5 kg of N-methylpyrrolidone and stir evenly to obtain a fluorinating agent ionic liquid. Place graphene powder in the fluorinating agent ionic liquid for reaction. The graphene powder and fluorinating agent ionic liquid are added at a mass ratio of 1:2. The reaction time is 8 hours and the temperature is maintained at 70℃. After the reaction is completed, solid-liquid separation is performed, and the collected solid is fluorinated graphene.

[0058] A3. Fluorinated graphene is washed with sufficient acetone to remove residual liquid and impurities, and then dried to obtain clean fluorinated graphene.

[0059] Preparation Example 6

[0060] The preparation method of fluorinated graphene is as follows:

[0061] A1. Prepare 5kg of fluorinated graphite, purchased from Huaxiang Kejie, CAS number 11113-63-6;

[0062] A2. Add 5 kg of fluorinated graphene powder to 8 kg of ethanol solution. Use an ultrasonic vibrator to ultrasonically disperse the ethanol solution for 8 min. Then, use a stirrer to mechanically stir the ethanol solution at high speed with a speed of 1100 r / min for 9 h. After stirring, transfer the graphene and ethanol mixture to a centrifuge and centrifuge at 5500 r / min for 8 min. After centrifugation, remove the supernatant and place the bottom precipitate in a vacuum drying oven at 60 °C for 10 h to obtain fluorinated graphene powder.

[0063] A3. Fluorinated graphene is washed with sufficient acetone to remove residual liquid and impurities, and then dried to obtain clean fluorinated graphene.

[0064] Example

[0065] Example 1

[0066] A method for preparing a high weather-resistant coating for a black backsheet of photovoltaic modules includes the following steps:

[0067] S1. Place 20 kg of fluorinated graphene in 100 kg of toluene solvent and ultrasonically disperse for 15 min to obtain a dispersion.

[0068] S2. Add 100 kg of tetrafluoroethylene fluorocarbon resin, 50 kg of acrylic resin, 5 kg of toughening agent and 10 kg of isocyanate to the dispersion, and stir at 500 r / min for 10 min to mix evenly to obtain a mixed coating.

[0069] S3. Stir the mixed coating at 100 r / min for 30 min in a vacuum environment of -0.1 MPa to remove air bubbles. After stirring, let it stand for 10 min to obtain a high weather-resistant coating for black backsheets of photovoltaic modules.

[0070] The toughening agent comprises 20% polyester polyol and 80% polyaspartic acid ester; the fluorinated graphene was prepared by Preparation Example 3.

[0071] Example 2

[0072] A method for preparing a high weather-resistant coating for a black backsheet of photovoltaic modules includes the following steps:

[0073] S1. Place 40 kg of fluorinated graphene in 200 kg of toluene solvent and ultrasonically disperse for 15 min to obtain a dispersion.

[0074] S2. Add 120 kg of tetrafluoroethylene fluorocarbon resin, 100 kg of acrylic resin, 30 kg of toughening agent and 30 kg of isocyanate to the dispersion, and stir at 500 r / min for 10 min to mix evenly to obtain a mixed coating.

[0075] S3. Stir the mixed coating at 100 r / min for 30 min in a vacuum environment of -0.1 MPa to remove air bubbles. After stirring, let it stand for 10 min to obtain a high weather-resistant coating for black backsheets of photovoltaic modules.

[0076] The toughening agent comprises 20% polyester polyol and 80% polyaspartic acid ester; the fluorinated graphene was prepared by Preparation Example 3.

[0077] Example 3

[0078] A method for preparing a high weather-resistant coating for a black backsheet of photovoltaic modules includes the following steps:

[0079] S1. Place 32 kg of fluorinated graphene in 175 kg of toluene solvent and ultrasonically disperse for 10-20 min to obtain a dispersion.

[0080] S2. Add 110 kg of tetrafluoroethylene fluorocarbon resin, 66 kg of acrylic resin, 15 kg of toughening agent and 18 kg of isocyanate to the dispersion, and stir at 500 r / min for 10 min to mix evenly to obtain a mixed coating.

[0081] S3. Stir the mixed coating at 100 r / min for 30 min in a vacuum environment of -0.1 MPa to remove air bubbles. After stirring, let it stand for 10 min to obtain a high weather-resistant coating for black backsheets of photovoltaic modules.

[0082] The toughening agent comprises 20% polyester polyol and 80% polyaspartic acid ester; the fluorinated graphene was prepared by Preparation Example 3.

[0083] Example 4

[0084] A method for preparing a high weather-resistant coating for a black backsheet of a photovoltaic module differs from Example 3 in that the fluorinated graphene is prepared by Example 1.

[0085] Example 5

[0086] A method for preparing a high weather-resistant coating for a black backsheet of a photovoltaic module differs from Example 3 in that the fluorinated graphene is prepared in Example 2.

[0087] Example 6

[0088] A method for preparing a high weather-resistant coating for a black backsheet of a photovoltaic module differs from Example 3 in that the fluorinated graphene is prepared in Example 4.

[0089] Example 7

[0090] A method for preparing a high weather-resistant coating for a black backsheet of a photovoltaic module differs from Example 3 in that the fluorinated graphene is prepared in Example 5.

[0091] Example 8

[0092] A method for preparing a high weather-resistant coating for a black backsheet of photovoltaic modules differs from Example 3 in that the toughening agent is 10% polyester polyol and 90% polyaspartic acid ester.

[0093] Example 9

[0094] A method for preparing a high weather-resistant coating for a black backsheet of photovoltaic modules differs from Example 3 in that the toughening agent is 30% polyester polyol and 70% polyaspartic acid ester.

[0095] Example 10

[0096] A method for preparing a high weather-resistant coating for a black backsheet of photovoltaic modules differs from Example 3 in that the weight ratio of tetrafluoroethylene-type fluorocarbon resin and acrylic resin is 1:0.5, and 110 kg of fluorocarbon resin and 55 kg of acrylic resin are added in step S2.

[0097] Example 11

[0098] A method for preparing a high weather-resistant coating for a black backsheet of photovoltaic modules differs from Example 3 in that the weight ratio of tetrafluoroethylene-type fluorocarbon resin and acrylic resin is 1:0.8, and 110 kg of fluorocarbon resin and 88 kg of acrylic resin are added in step S2.

[0099] Comparative Example

[0100] Comparative Example 1

[0101] A method for preparing a high weather-resistant coating for a black backsheet of photovoltaic modules includes the following steps:

[0102] S1. Place 32 kg of graphene in 175 kg of toluene solvent and ultrasonically disperse for 10-20 min to obtain a dispersion.

[0103] S2. Add 110 kg of tetrafluoroethylene fluorocarbon resin, 66 kg of acrylic resin, 15 kg of toughening agent and 18 kg of isocyanate to the dispersion, and stir at 500 r / min for 10 min to mix evenly to obtain a mixed coating.

[0104] S3. Stir the mixed coating at 100 r / min for 30 min in a vacuum environment of -0.1 MPa to remove air bubbles. After stirring, let it stand for 10 min to obtain a high weather-resistant coating for black backsheets of photovoltaic modules.

[0105] The toughening agent includes 20% polyester polyol and 80% polyaspartic acid ester.

[0106] Comparative Example 2

[0107] A method for preparing a high weather-resistant coating for a black backsheet of photovoltaic modules includes the following steps:

[0108] S1. Place 32 kg of fluorinated graphene in 175 kg of toluene solvent and ultrasonically disperse for 10-20 min to obtain a dispersion.

[0109] S2. Add 110 kg of tetrafluoroethylene fluorocarbon resin, 66 kg of acrylic resin, 15 kg of toughening agent and 18 kg of isocyanate to the dispersion, and stir at 500 r / min for 10 min to mix evenly to obtain a mixed coating.

[0110] S3. Stir the mixed coating at 100 r / min for 30 min in a vacuum environment of -0.1 MPa to remove air bubbles. After stirring, let it stand for 10 min to obtain a high weather-resistant coating for black backsheets of photovoltaic modules.

[0111] The toughening agent comprises 20% polyester polyol and 80% polyaspartic acid ester; the fluorinated graphene was prepared by Preparation Example 6.

[0112] Comparative Example 3

[0113] A method for preparing a high weather-resistant coating for a black backsheet of photovoltaic modules includes the following steps:

[0114] S1. Place 32 kg of fluorinated graphene in 175 kg of toluene solvent and ultrasonically disperse for 10-20 min to obtain a dispersion.

[0115] S2. Add 176 kg of tetrafluoroethylene fluorocarbon resin, 15 kg of toughening agent and 18 kg of isocyanate to the dispersion, and stir at 500 r / min for 10 min to mix evenly to obtain a mixed coating.

[0116] S3. Stir the mixed coating at 100 r / min for 30 min in a vacuum environment of -0.1 MPa to remove air bubbles. After stirring, let it stand for 10 min to obtain a high weather-resistant coating for black backsheets of photovoltaic modules.

[0117] The toughening agent comprises 20% polyester polyol and 80% polyaspartic acid ester; the fluorinated graphene was prepared by Preparation Example 3.

[0118] Comparative Example 4

[0119] A method for preparing a high weather-resistant coating for a black backsheet of photovoltaic modules includes the following steps:

[0120] S1. Place 32 kg of fluorinated graphene in 175 kg of toluene solvent and ultrasonically disperse for 10-20 min to obtain a dispersion.

[0121] S2. Add 110 kg of tetrafluoroethylene fluorocarbon resin, 66 kg of acrylic resin, 15 kg of toughening agent and 18 kg of isocyanate to the dispersion, and stir at 500 r / min for 10 min to mix evenly to obtain a mixed coating.

[0122] S3. Stir the mixed coating at 100 r / min for 30 min in a vacuum environment of -0.1 MPa to remove air bubbles. After stirring, let it stand for 10 min to obtain a high weather-resistant coating for black backsheets of photovoltaic modules.

[0123] The toughening agent comprises 50% polyester polyol and 50% polyaspartic acid ester; the fluorinated graphene was prepared by Preparation Example 3.

[0124] Performance testing

[0125] Peel strength test method: Peel strength tests were conducted on Examples 1-11 and Comparative Examples 1-4 according to GB / T2790 standard;

[0126] Damp heat test: Conducted according to IEC 61215-2005, accelerated aging was performed in a temperature and humidity chamber at 85℃±2℃ and (85±5)%RH. The peel strength of Examples 1-11 and Comparative Examples 1-4 after aging for 1000 hours was recorded.

[0127] Impact resistance test: Examples 1-11 and Comparative Examples 1-4 were tested according to GB / T1732-1993.

[0128] Wear resistance test: The wear resistance of the coating was tested using a CFT-I type material surface comprehensive performance tester. In the test, a ball-disc reciprocating friction method was adopted, with the friction ball being a 4mm diameter GCr15 steel ball. A force of 3N was applied in the vertical direction, and the ball was rubbed back and forth at a speed of 300r / min for 30 minutes. The test results were recorded and the wear rate was calculated.

[0129] Table 1. Statistical Analysis of Experimental Data

[0130]

[0131]

[0132] Combining Example 3 and Comparative Example 1 with Table 1, it can be seen that the graphene used in Comparative Example 1 was not fluorinated. After being added to the coating, it was significantly weaker than Example 3 in terms of peel strength, wear resistance, and impact resistance. This shows that the barrier properties and interface enhancement effect of fluorinated graphene can reduce the penetration of external corrosive substances, improve the durability and mechanical strength of the coating, effectively improve the wear resistance of the coating, protect the coating from environmental erosion and aging, and extend the service life of the coating.

[0133] As can be seen from Example 3 and Comparative Example 2, and in conjunction with Table 1, Comparative Example 2 used a method of preparing fluorinated graphene from fluorinated graphite through mechanical shearing. Compared with Example 3, the peel strength, wear resistance, and impact resistance were all lower than those of Example 3. This indicates that the method used in this application to prepare Example 3 resulted in a higher degree of fluorination of the fluorinated graphene. Highly fluorinated graphene exhibits better surface wettability and adhesion to substrates, significantly improving tribological properties.

[0134] Based on Example 3 and Comparative Example 3, and referring to Table 1, it can be seen that Comparative Example 3, which did not use acrylic resin in combination with fluorocarbon resin, has weaker performance than Example 3. This indicates that acrylic resin has high weather resistance and chemical stability, which can enhance the weather resistance of the coating. The acrylic resin side chain blended with fluorocarbon resin contains a longer carbon chain, which can enhance the entanglement between the molecular chains of EVA resin and improve the adhesion. In addition, the acrylic resin main chain has more ester bond groups, which is beneficial to improve its adhesion to the polyester film.

[0135] Combining Example 3 and Comparative Example 4 with Table 1, it can be seen that the toughening agent ratio in Comparative Example 4 is not within the range of 10-30% polyester polyol and 70-90% polyaspartic acid ester. This demonstrates that by mixing these two toughening agents in an appropriate ratio, their advantages can be comprehensively utilized, significantly improving the toughness and adhesion of the coating without affecting its weather resistance. A reasonable ratio allows the coating to be more evenly distributed on the coated surface, reducing defects and unevenness in the coating. Exceeding this ratio range will seriously affect the adhesion and surface quality of the coating.

[0136] As can be seen from Examples 1-3 and Table 1, by changing the proportions of each group, the performance of the coating can be improved, and the proportions in Example 3 are the optimal ones.

[0137] As can be seen from Examples 3-7 and Table 1, the performance of fluorinated graphene can be optimized by changing the reagent ratio in the preparation of fluorinated graphene, with Example 3 being the optimal one.

[0138] As can be seen from Examples 3 and 8-11 and Table 1, by changing the toughening agent ratio, the toughening and strengthening effect on the coating can be further optimized; by controlling the addition ratio of fluorocarbon resin and acrylic resin, the synergistic effect between fluorocarbon resin and acrylic resin can be maximized, thereby further improving the weather resistance, chemical stability and mechanical strength of the coating.

[0139] 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. A high weather-resistant coating for a black backsheet of photovoltaic modules, characterized in that, By weight, it includes 100-120 parts of fluorocarbon resin, 50-100 parts of acrylic resin, 20-40 parts of fluorinated graphene, 5-30 parts of toughening agent, 10-30 parts of curing agent and 100-200 parts of solvent. The weight ratio of the fluorocarbon resin to the acrylic resin is 1:(0.5-0.8). The toughening agent is composed of polyester polyol and polyaspartic acid ester, wherein the polyester polyol accounts for 10-30% of the total weight of the toughening agent, and the polyaspartic acid ester accounts for 70-90% of the total weight of the toughening agent; The fluorinated graphene is prepared by a method comprising the following steps: A1. Place graphite powder in an ethanol solution and ultrasonically disperse for 5-10 min, then perform high-speed mechanical shearing and stirring at a speed of 1000-1200 r / min for 8-10 h. After stirring, centrifuge at 5000-6000 r / min for 5-10 min, and place the bottom precipitate in a vacuum drying oven at 50-70℃ for 10-12 h to obtain graphene powder. A2. Hydrofluoric acid and N-methylpyrrolidone are mixed at a mass ratio of 1:(2-4) to obtain a fluorinating agent ionic liquid. The graphene powder is placed in the fluorinating agent ionic liquid for reaction. The mass ratio of graphene powder to fluorinating agent ionic liquid is 1:(1-2). The reaction time is 6-10 h and the temperature is 60-80℃ to obtain fluorinated graphene. A3. After the reaction is complete, the fluorinated graphene is washed with acetone and then dried to obtain clean fluorinated graphene.

2. The high weather-resistant coating for black backsheets of photovoltaic modules according to claim 1, characterized in that, By weight, it comprises 110 parts of fluorocarbon resin, 66 parts of acrylic resin, 32 parts of fluorinated graphene, 15 parts of toughening agent, 18 parts of curing agent, and 175 parts of solvent.

3. The high weather-resistant coating for black backsheets of photovoltaic modules according to claim 1, characterized in that, The curing agent includes one or more of isocyanate, amino resin and melamine.

4. The high weather-resistant coating for black backsheets of photovoltaic modules according to claim 1, characterized in that, The solvent includes one or more of toluene, xylene, ethyl acetate, and butyl acetate.

5. A method for preparing a high weather-resistant coating for a black backsheet of a photovoltaic module as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Place fluorinated graphene in a solvent and sonicate for 10-20 min to obtain a dispersion. S2. Add the fluorocarbon resin, acrylic resin, toughening agent, curing agent and remaining solvent to the dispersion, stir for 5-10 minutes to mix evenly, and obtain a mixed coating. S3. Stir the mixed coating in a vacuum environment to remove air bubbles, and then let it stand for 5-15 minutes to obtain the high weather-resistant coating for the black backsheet of photovoltaic modules.

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