Photovoltaic ECTFE transparent front plate

Abstract

The invention discloses a photovoltaic ECTFE transparent front plate, the photovoltaic ECTFE transparent front plate sequentially comprises an ECTFE film layer, an ultraviolet blocking layer, a water vapor blocking layer and a fiber reinforcement layer, and the ultraviolet blocking layer is made of a copolymer of fluorinated acrylate, acrylate containing ultraviolet absorption groups and acrylate containing hydroxyl and an aliphatic isocyanate cross-linking curing material. According to the photovoltaic ECTFE transparent front plate, the visible light transmittance is larger than or equal to 90%, the ultraviolet rejection rate is larger than or equal to 95%, and the water vapor transmittance is smaller than 0.01 g / m < 2 > 24h.

Description

Technical Field

[0001] The present invention relates to the field of polymer processing applications, and particularly to an ECTFE transparent front plate for photovoltaic use. Background Art

[0002] With the increasing global demand for renewable energy, the photovoltaic installed capacity has also grown rapidly. In recent years, in addition to large-scale ground power stations, distributed photovoltaics have also developed rapidly. Application scenarios such as industrial and commercial rooftops, mobile and portable components, and curtain walls have enabled components to continuously develop in the direction of light weight and flexibility. Lightweight and flexible components, due to their performance characteristics such as flexibility and light weight, will have a broad market development space.

[0003] Currently, the mainstream solution for lightweight components is to replace the traditional photovoltaic glass used for encapsulation with a transparent polymer material to achieve the characteristics of lightweight and partial bending of the lightweight components. In particular, as the outer layer protection on the front side of the component, the polymer material needs to withstand ultraviolet irradiation of more than 2000 kWh / m 2 In addition, in the face of complex environments such as hail, rain, and snow, it is still necessary to ensure that the solar cells do not undergo hidden cracks, and the encapsulation material does not show delamination, yellowing, etc. At the same time, the occurrence of the PID phenomenon is avoided, and thus the high power generation efficiency of the component for more than 25 years is ensured. This poses challenges to the key material selection and structural design of the polymer encapsulation material.

[0004] Due to its characteristics, polymer encapsulation materials generally suffer from yellowing, failure, delamination, etc. caused by intolerance to long-term aging. Components using polymer encapsulation materials have low mechanical strength, resulting in hidden cracks in the solar cells in snowy and icy weather, thereby causing a decline in the power generation efficiency of the components. At the same time, due to its low water vapor barrier, the PID phenomenon occurs in the components.

[0005] To solve the above technical problems, some research and exploration have been carried out on the encapsulation structure and material selection of lightweight components:

[0006] CN210167364U discloses a lightweight and flexible photovoltaic module. The photovoltaic module sequentially includes a TFB film layer, a water barrier film layer, a composite glass fiber layer, a battery string, and an FFC double-sided fluorinated back film layer from top to bottom. The TFB film layer is connected to the water barrier film layer, the water barrier film layer is connected to the composite glass fiber layer, the composite glass fiber layer is connected to the battery string, and the battery string is connected to the FFC double-sided fluorinated back film layer through an EVA film. A coating solution is sprayed on the side of the TFB film layer away from the water barrier film layer. The water barrier film layer sequentially includes an EVA adhesive layer, a PET film layer, a high barrier layer, a PE protective layer, and an EVA adhesive layer. Its key TFB layer adopts a structural method of PVF / PET / fluorinated binder. Due to its low fluorine content and lack of ultraviolet absorption function, the weather resistance of the front plate cannot meet the 25-year ultraviolet irradiation on the front side.

[0007] CN112420864A discloses a lightweight overlapping tile photovoltaic module based on a glass fiber pre - impregnation process. This photovoltaic module is sequentially laminated and encapsulated by a transparent flexible front film, a first - layer high - transparency EVA film, a high - transparency glass fiber pre - impregnated material, a second - layer high - transparency EVA film, an overlapping tile battery string, a first - layer high - cut - off EVA film, a rear - layer glass fiber pre - impregnated material, a second - layer high - cut - off EVA film, and a photovoltaic backplane. The water vapor transmission rate of this module is relatively high, which easily causes the EVA to hydrolyze and the module to exhibit the PID phenomenon, reducing the power generation efficiency of the module.

[0008] Both of the above two solutions use glass fiber reinforcement to increase the impact resistance of the module. Therefore, from the aspects of ultraviolet resistance and water vapor barrier performance, the above two solutions are not sufficient to enable the flexible module to meet the requirements of long - term high power generation efficiency in the photovoltaic industry. Summary of the Invention

[0009] In view of the above - mentioned technical problems, the present invention uses a highly weather - resistant ECTFE film as the base material, and realizes ultraviolet blocking of more than 95% through an ultraviolet - blocking layer made of a copolymer of fluoroacrylate, acrylate containing an ultraviolet - absorbing group, and acrylate containing a hydroxyl group and an aliphatic isocyanate cross - linking curing material, and realizes a water vapor transmission rate < 0.01g / m 2 24h through a water vapor barrier layer.

[0010] The technical solution of the present invention is as follows:

[0011] The present invention provides an ECTFE transparent front plate for photovoltaic use, which sequentially includes an ECTFE film layer, an ultraviolet - blocking layer, a water vapor barrier layer, and a fiber - reinforced layer. The ultraviolet - blocking layer is a material obtained by cross - linking and curing a copolymer of fluoroacrylate, acrylate containing an ultraviolet - absorbing group, and acrylate containing a hydroxyl group with an aliphatic isocyanate.

[0012] The thickness of the ECTFE film layer only needs to meet the photovoltaic requirements. Preferably, the thickness is 10 - 100um, and more preferably, it is 15 - 50um.

[0013] The preparation method of the ECTFE film layer is: ECTFE resin, processing aids such as antioxidants and heat stabilizers are granulated by a twin - screw extruder, and after granulation, it is obtained by single - screw extrusion casting or extrusion blow molding.

[0014] The thickness of the ultraviolet - blocking layer only needs to meet the photovoltaic requirements. Preferably, the thickness is 1 - 10um, and more preferably, it is 2 - 5um.

[0015] The copolymer of fluoroacrylate, acrylate containing an ultraviolet - absorbing group, and acrylate containing a hydroxyl group is shown in formula (1),

[0016]

[0017] Among them, R1 is selected from H and CH3,

[0018] R2 is where n is an integer from 1 to 3,

[0019] R3 is selected from -CH2CH2- and -CH2CH2CH2-,

[0020] x + y + z = 1, x = 0.5 to 0.8, y = 0.1 to 0.3, z = 0.1 to 0.2.

[0021] Furthermore, the fluoroacrylate is selected from at least one of trifluoromethyl acrylate and trifluoromethyl methacrylate; the hydroxy-containing acrylate is selected from at least one of methyl hydroxypropyl acrylate and methyl hydroxyethyl acrylate.

[0022] The aliphatic isocyanate is selected from at least one of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and dicyclohexylmethane - 4,4'-diisocyanate (HMDI).

[0023] The crosslinking and curing temperature of the compound shown in formula (1) and the aliphatic isocyanate is 100 to 120 °C, the time is 0.5 to 2 min, the curing temperature is 50 to 90 °C, and the time is 24 h to 72 h.

[0024] Since the ultraviolet barrier layer is a crosslinked and cured material, substances with ultraviolet absorption properties are not likely to precipitate, and the ultraviolet barrier performance can be achieved for a long time.

[0025] The thickness of the water vapor barrier layer only needs to meet the photovoltaic requirements. Preferably, the thickness is 10 to 100 μm.

[0026] The water vapor barrier layer is selected from at least one of silicon oxide, silicon nitride, and aluminum oxide.

[0027] The surface density of the fiber reinforced layer only needs to meet the photovoltaic light weight requirements. Preferably, it is 40 to 400 g / m 2 .

[0028] The preparation method of the fiber reinforced layer includes the steps of mixing a hydroxyl-terminated acrylic resin, a reactive ultraviolet absorber, a reactive light stabilizer, and an aliphatic isocyanate into a uniform first solution, and dipping a transparent glass fiber cloth into the first solution. The molecular weight of the hydroxyl-terminated acrylic resin is 10,000 to 500,000, and the hydroxyl value is 20 to 60.

[0029] The reactive ultraviolet absorber is selected from at least one of 2-[4-[2-hydroxy-3-tridecyloxypropyl]oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine and 2-[2-hydroxy-4-[3-(2-ethylhexyloxy)-2-hydroxypropoxy]phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, and the reactive light stabilizer is 2,4-di[N-butyl-(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)amino]-6-(2-hydroxyethylamine)-1,3,5-triazine.

[0030] The photovoltaic ECTFE transparent front plate of the present invention comprises an ECTFE film layer, an ultraviolet barrier layer, a water vapor barrier layer, and a fiber reinforcement layer in sequence;

[0031] The ultraviolet blocking layer is coated and laminated with the ECTFE film layer to obtain a first film, and the coating liquid is prepared by fully mixing the compound represented by formula (1), aliphatic isocyanate and a solvent.

[0032] After the ECTFE film layer is coated with the UV barrier layer, the side coated with the UV barrier layer is facing upward, and a method selected from vacuum evaporation, atomic deposition, magnetron sputtering or PECVD is used to laminate the water vapor barrier layer material to the UV barrier layer to obtain a second film.

[0033] The preparation method of the fiber reinforced layer includes the steps of mixing a terminal hydroxyl acrylic resin, a reactive ultraviolet absorber, a reactive light stabilizer and an aliphatic isocyanate into a uniform first solution, immersing a transparent glass fiber cloth in the first solution, and after the transparent glass fiber cloth comes out of the first solution, compounding, pre-curing and ripening with the second film to obtain the photovoltaic ECTFE transparent front plate.

[0034] The aliphatic isocyanate is selected from at least one of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and dicyclohexylmethane-4,4'-diisocyanate (HMDI).

[0035] The photovoltaic ECTFE transparent front plate of the present invention has a visible light transmittance of ≥90%, a UV blocking rate of ≥95%, and a water vapor transmittance of <0.01 g / m 2 .24h.

[0036] The ultraviolet radiation of the photovoltaic ECTFE transparent front plate of the present invention is 2000kWh / m 2 The yellowness value after aging is less than 0.5, and the yellowness value after aging for 96 hours at a temperature of 121°C and a humidity of 100RH is less than 0.5.

[0037] Compared with the prior art, the technical solution of the present invention has the following technical effects:

[0038] Using an ECTFE film as the base material, its good water vapor barrier property ensures that the acrylate structure in the ultraviolet barrier layer will not be hydrolytically damaged, and at the same time, wear of the ultraviolet barrier layer is avoided.

[0039] The fiber-reinforced layer is compounded with the ECTFE film layer loaded with the ultraviolet barrier layer and the water vapor barrier layer, avoiding the use of EVA / POE, realizing continuous production, and improving production efficiency. Description of the Drawings

[0040] Figure 1 It is a schematic diagram of the film lamination of the embodiment and the comparative example of the present invention, where 1 is a roll of fiberglass cloth, 2-5 are transition rollers, 6 is a tank for solution A, 7 is a transition roller, 8 is a roll of ECTFE film, 9 is an unwinding of the release film, 10 is a winding of the release film, 11-12 are pressure rollers, 13-16 are transition rollers, 17 is a heating drying channel, and 18 is an ECTFE photovoltaic panel. Detailed Embodiments

[0041] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all alternative, improved, and equivalent solutions that may be included within the scope of the claims.

[0042] Example 1

[0043] (1) 100 parts of ECTFE resin, 0.1 part of antioxidant 1790, and 0.4 part of antioxidant 9228 are mixed evenly at high speed. The mixed material is granulated by a twin-screw extruder, and the ECTFE pellets are extruded and cast by a single-screw extruder to obtain an ECTFE film with a thickness of 25 μm.

[0044] Extrusion and casting process parameters

[0045] Extrusion temperature Melt pump temperature Die temperature Cast roll temperature Screw speed Cast roll speed 265℃ 260℃ 270℃ 150℃ 50 rpm 20 m / min

[0046] (2) 112 g of trifluoromethyl acrylate, 15 g of 2-hydroxyethyl methacrylate, and 35 g of 2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]ethyl 2-methylacrylate are dissolved in 800 mL of xylene, added to a 5 L glass reaction kettle with mechanical stirring. After three nitrogen replacements, the temperature is raised to 70 °C, 1.5 g of azobisisobutyronitrile is added, and after reacting for 6 h, the temperature is lowered to obtain a fluorinated methyl acrylate copolymer solution.

[0047] After thoroughly mixing 2 g of HDI (hexamethylene diisocyanate), 100 g of methyl fluoroacrylate copolymer solution, and 0.01 g of dibutyltin dilaurate, it was slit-coated on a 25-μm ECTFE film. After passing through a 120°C drying oven for 0.5 min, it was placed in a 60°C oven for curing for 48 h to obtain Film1 with a 2-μm-thick ultraviolet barrier layer.

[0048] (3) Magnetron sputtering was carried out on the ultraviolet barrier layer of Film1, with the target material being SiO2 and the thickness of the inorganic sputtering layer (water vapor barrier layer) being 50 nm to obtain Film2.

[0049] (4) Mix 35 g of ultraviolet absorber 2-[4-[2-hydroxy-3-tridecyloxypropyl]oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 25 g of ultraviolet absorber 2,4-bis[N-butyl-(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)amine]-6-(2-hydroxyethylamine)-1,3,5-triazine, 4 g of HDI, and 1700 g of hydroxy-terminated acrylic resin 587 (molecular weight 17,000), and 5 L of ethyl acetate were thoroughly mixed together to obtain solution A. The pre-woven fiberglass cloth was immersed in solution A and then on-line laminated with the unwound Film 2 and the unwound release film. After heating in a 100°C drying oven for 0.5 min, it was on-line cut into specified sizes and cured at 60°C for 48 h to obtain the ECTFE transparent front plate Sheet1 for photovoltaic use.

[0050] Example 2

[0051] Same as Example 1, except that: the thickness of the ultraviolet barrier layer is 5 μm.

[0052] Example 3

[0053] Same as Example 1, except that: the thickness of the water vapor barrier layer is 100 nm.

[0054] Example 4

[0055] Same as Example 1, except that: 98 g of trifluoromethyl acrylate, 15 g of hydroxyethyl methyl acrylate, and 70 g of 2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]ethyl methacrylate were dissolved in 20 parts of xylene, added to a 5-L glass reaction kettle with mechanical stirring. After three nitrogen replacements, the temperature was raised to 70°C, 0.05 part of AIBN was added, and after reacting for 6 h, the temperature was lowered to obtain the methyl fluoroacrylate copolymer solution.

[0056] Example 5

[0057] Same as Example 1, except that: the target material is Al2O3 and the thickness of the water vapor barrier layer is 50 nm.

[0058] Comparative Example 1: Without an ultraviolet barrier layer

[0059] Magnetron sputtering was carried out on a 25um ECTFE film with a SiO2 target, and the thickness of the inorganic sputtering layer (water vapor barrier layer) was 50nm to obtain Film1.

[0060] 35g of ultraviolet absorber 2-[4-[2-hydroxy-3-tridecyloxypropyl]oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 25g of ultraviolet absorber 2,4-bis[N-butyl-(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)amine]-6-(2-hydroxyethylamine)-1,3,5-triazine, 4g of HDI, and 1700g of hydroxyl-terminated acrylic resin 587 (molecular weight 17,000), 5L of ethyl acetate were fully mixed to obtain Solution A. A pre-prepared fiberglass cloth was immersed in Solution A and laminated online with the unwound Film1 and the unwound release film. After heating in a drying oven at 100°C for 0.5 min, it was cut into a specified size online and cured at 60°C for 48 h to obtain an ECTFE transparent front plate for photovoltaic use.

[0061] Comparative Example 2: Without a water vapor barrier layer

[0062] 112g of trifluoromethyl acrylate, 15g of 2-hydroxyethyl methacrylate, and 35g of 2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]ethyl methacrylate were dissolved in 800mL of xylene and added to a 5L glass reaction kettle with mechanical stirring. After three nitrogen replacements, the temperature was raised to 70°C, and 1.5g of azobisisobutyronitrile was added. After reacting for 6h, the temperature was lowered to obtain a fluorinated methyl acrylate copolymer solution.

[0063] 2g of HDI (hexamethylene diisocyanate), 100g of fluorinated methyl acrylate copolymer solution, and 0.01g of dibutyltin dilaurate were fully mixed and then coated on a 25um ECTFE film through a slit coater. After passing through a drying oven at 120°C for 0.5 min, it was placed in an oven at 60°C for curing for 48 h to obtain Film1 with an ultraviolet barrier layer thickness of 2um.

[0064] 35g of ultraviolet absorber 2-[4-[2-hydroxy-3-tridecyloxypropyl]oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 25g of ultraviolet absorber 2,4-bis[N-butyl-(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)amine]-6-(2-hydroxyethylamine)-1,3,5-triazine, 4g of HDI, and 1700g of hydroxyl-terminated acrylic resin 587 (molecular weight 17,000), 5 L of ethyl acetate were thoroughly mixed together to obtain Solution A. A pre-prepared fiberglass cloth was immersed in Solution A and then laminated online with the unwound Film1 and the unwound release film. After heating in a drying oven at 100 °C for 0.5 min, it was cut into specified dimensions online and then cured at 60 °C for 48 h to obtain the ECTFE transparent front plate for photovoltaics.

[0065] Comparative Example 3: The reinforcing layer was PET

[0066] 112 g of trifluoromethyl acrylate, 15 g of 2-hydroxyethyl methacrylate, and 35 g of 2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]ethyl methacrylate were dissolved in 800 mL of xylene and added to a 5 L glass reaction kettle with mechanical stirring. After three nitrogen replacements, the temperature was raised to 70 °C, and 1.5 g of azobisisobutyronitrile was added. After reacting for 6 h, the temperature was lowered to obtain a copolymer solution of methyl fluoroacrylate.

[0067] 2 g of HDI (hexamethylene diisocyanate), 100 g of the copolymer solution of methyl fluoroacrylate, and 0.01 g of dibutyltin dilaurate were thoroughly mixed and then coated on a 25-μm ECTFE film through a slit coater. After passing through a drying oven at 120 °C for 0.5 min, it was placed in an oven at 60 °C for curing for 48 h to obtain Film1 with a UV barrier layer thickness of 2 μm.

[0068] Magnetron sputtering was carried out on the UV barrier layer of Film1, with the target material being SiO2 and the thickness of the inorganic sputtering layer (water vapor barrier layer) being 50 nm to obtain Film2.

[0069] Film2 and 250-μm PET were laminated by dry lamination to obtain the ECTFE transparent front plate for photovoltaics.

[0070] For the ECTFE transparent front plates for photovoltaics prepared in Examples 1-5 and Comparative Examples 1-3, their UV barrier rate, visible light transmittance, water vapor transmission rate, yellowness after 96 h of accelerated damp heat aging, yellowness after 2000 kWh / m 2 of UV irradiation, and component power loss (35-mm hail impact test) were tested. The test results are shown in Table 2 in detail.

[0071] The test methods are as follows:

[0072] UV barrier rate: Tested in accordance with ASTM G173.

[0073] Visible light transmittance: Tested in accordance with GB / T 18830.

[0074] Water vapor transmission rate: Tested in accordance with GB / T 1037.

[0075] Yellowing value: Tested according to GB / T 7921, read the initial state L0, a0, b0, and read the final state L1, a1, b1. The yellowing value db = b1 - b0.

[0076] Accelerated damp heat aging: Keep at a temperature of 121 °C and a humidity of 100RH for 96h.

[0077] UV irradiation: Irradiation intensity 1.55W / m 2 @340nm, blackboard temperature 65 °C, continuous light irradiation, cumulative irradiation dose 2000kWh / m 2 。

[0078] Component power loss (35mm hail impact test): Tested according to IEC 61215.

[0079] Table 2 Performance data of ECTFE transparent front plate for photovoltaics

[0080]

[0081] It can be seen from the data in Table 2 that:

[0082] It can be found from the data of Examples 1-5 that the transparent front plate prepared by the combination of the UV barrier layer, the water vapor barrier layer and the fiber reinforcement layer has excellent performance and can meet the 25-year use requirements of photovoltaic lightweight components. It can be found from the data of Comparative Example 1 that in the scheme without using the UV barrier layer, the resin in the fiber reinforcement layer will turn yellow, affecting the appearance of the component. It can be found from Comparative Example 2 that in the scheme without using the water vapor barrier layer, the permeation of water vapor leads to the yellowing of the glass fiber reinforcement layer. It can be found from Comparative Example 3 that using PET to replace the fiber reinforcement layer reduces the impact resistance of the transparent front plate, thereby reducing the power generation efficiency of the component.

Claims

1. An ECTFE transparent front plate for photovoltaics, characterized in that: The ECTFE transparent front plate for photovoltaic applications sequentially includes an ECTFE film layer, an ultraviolet barrier layer, a water vapor barrier layer, and a fiber reinforcement layer. The ultraviolet barrier layer is a material obtained by crosslinking and curing a copolymer of fluoroacrylate, acrylate containing an ultraviolet absorption group, and acrylate containing a hydroxyl group with an aliphatic isocyanate.

2. The ECTFE transparent front plate for photovoltaics according to claim 1, characterized in that: The copolymer of fluoroacrylate, acrylate containing an ultraviolet absorption group, and acrylate containing a hydroxyl group is shown in Formula (1). Wherein, R1 is selected from H and CH3. R2 is where n is an integer from 1 to 3 R3 is selected from -CH2CH2- and -CH2CH2CH2-. x + y + z = 1, x = 0.5 to 0.8, y = 0.1 to 0.3, z = 0.1 to 0.

2.

3. The ECTFE transparent front plate for photovoltaics according to claim 1, characterized in that: The aliphatic isocyanate is selected from at least one of hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane-4,4'-diisocyanate.

4. The ECTFE transparent front plate for photovoltaics according to any one of claims 1 - 3, characterized in that: The thickness of the ultraviolet barrier layer is 1 to 10 μm.

5. The ECTFE transparent front plate for photovoltaics according to claim 1, characterized in that: The water vapor barrier layer is selected from at least one of silicon oxide, silicon nitride, and aluminum oxide, and the thickness of the water vapor barrier layer is 10 to 100 nm.

6. The ECTFE transparent front plate for photovoltaics according to claim 1, characterized in that: The preparation method of the fiber reinforcement layer includes the steps of mixing a hydroxyl-terminated acrylic resin, a reactive ultraviolet absorber, a reactive light stabilizer, and an aliphatic isocyanate into a uniform first solution, and dipping a transparent glass fiber cloth into the first solution. The molecular weight of the hydroxyl-terminated acrylic resin is 10,000 to 500,000, and the hydroxyl value is 20 to 60.

7. The ECTFE transparent front plate for photovoltaics according to claim 6, characterized in that: The reactive ultraviolet absorber is selected from at least one of 2-[4-[2-hydroxy-3-tridecyloxypropyl]oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine and 2-[2-hydroxy-4-[3-(2-ethylhexyloxy)-2-hydroxypropoxy]phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, and the reactive light stabilizer is 2,4-bis[N-butyl-(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)amine]-6-(2-hydroxyethylamine)-1,3,5-triazine.

8. The ECTFE transparent front plate for photovoltaics according to claim 1, characterized in that: The thickness of the ECTFE film layer is 10 to 100 μm.

9. The ECTFE transparent front plate for photovoltaics according to claim 1, characterized in that: The visible light transmittance of the ECTFE transparent front plate for photovoltaics is ≥90%, the ultraviolet barrier rate is ≥95%, and the water vapor transmission rate is <0.01 g / m 2 24h.

10. The ECTFE transparent front plate for photovoltaics according to claim 1, characterized in that: The ECTFE for photovoltaic applications The yellowing value of the transparent front panel after ultraviolet irradiation of 2000 kWh / m 2 is < 0.5, and the yellowing value after aging at a temperature of 121 °C and a humidity of 100 RH for 96 h is < 0.5.

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