CN114686055A - A fluorocarbon coating solution, a fluorocarbon coating, and a solar back panel - Google Patents

Abstract

The invention relates to the technical field of solar back plates, in particular to a fluorocarbon coating liquid, a fluorocarbon coating and a solar back plate. In order to solve the problem of poor heat resistance of the transparent fluorocarbon coating, the invention provides a fluorocarbon coating liquid, a fluorocarbon coating and a solar back plate. The fluorocarbon coating liquid comprises, by weight, 50% -80% of fluorocarbon resin, 3% -10% of inorganic nano cerium dioxide UV absorbent, 1% -5% of matting powder, 10% -20% of adhesion promoter, 0.3% -0.8% of additive and 5% -20% of isocyanate. The coating formed by the fluorocarbon coating liquid has good heat resistance at a hot spot temperature (such as 170 ℃), is not easy to precipitate micromolecules and degrade macromolecules, and does not yellow in the high-temperature hot spot test process after the assembly is subjected to heat sealing.

Description

A fluorocarbon coating solution, a fluorocarbon coating, and a solar back panel

technical field

The invention relates to the technical field of solar back sheets, in particular to a fluorocarbon coating solution, a fluorocarbon coating, and a solar back sheet.

Background technique

In order to solve the power generation problem of photovoltaic modules, the current size of silicon wafer cells has changed from the traditional 163mm, 166mm to 182mm, 210mm large size. Along with the increase in overall component power, more stringent demands are placed on traditional backplanes. The development and application of transparent components has made an indelible contribution to the improvement of component power. Compared with traditional modules, the power of transparent large-scale modules has exceeded 550W, and the current heating effect in the power generation process has become an inevitable fact.

Due to the thermal effect caused by high current, it can be simulated by the hot spot effect in photovoltaic modules. The hot spot temperature of large modules has exceeded 170°C, which is more than 20°C higher than that of traditional modules. This high temperature places higher thermal demands on the backside encapsulation material backplane. Small molecules added in general transparent fluorocarbon formulations face the risk of precipitation and degradation at this temperature.

SUMMARY OF THE INVENTION

In order to solve the problem of poor heat resistance of the transparent fluorocarbon coating, the present invention provides a fluorocarbon coating solution, a fluorocarbon coating, and a solar back sheet. The coating formed by the fluorocarbon coating solution has good heat resistance at the hot spot temperature (for example, 170°C), and there is no obvious change in appearance, indicating that the precipitation of small molecules and the degradation of macromolecules are not easy to occur. No yellowing of the coating occurs during the high temperature hot spot test.

Further, in order to solve the problem of thermal effect caused by the enlargement of the current photovoltaic modules, the present invention provides a fluorocarbon coating solution, a fluorocarbon coating, and a solar back sheet. The fluorocarbon coating is an ultraviolet absorber coating of inorganic nano-cerium oxide. Compared with the prior art, the solution provided by the present invention has the advantage of being sufficiently stable in heat resistance, and compared with the traditional organic UV absorber, the coating will not be consumed or damaged during the hot spot test. Therefore, the reasonable selection of more stable inorganic nano UV absorbers has far-reaching significance for improving the heat resistance of transparent coatings.

The invention provides a fluorocarbon coating solution, which comprises 50%-80% by weight of fluorocarbon resin, 3%-10% of inorganic nano-cerium dioxide UV absorber, 1% by weight ～5% Matting Powder, 10%～20% Adhesion Promoter, 0.3%～0.8% Additive, 5%～20% Isocyanate.

Further, the particle size of the inorganic ceria nanoparticles is 10-30 nm.

Further, the fluorocarbon coating solution further includes an organic solvent, and the solid content is 50% to 70%.

The fluorocarbon coating liquid is also called fluorocarbon coating.

The ratio of the fluorocarbon coating liquid is limited to the above range, which has excellent adhesion on the transparent layer after curing, and meets the requirements of packaging strength. At the same time, due to the use of inorganic nano-absorbents, it is not easy to decompose at high temperatures. , thereby improving the hot spot resistance of the overall assembly.

Further, the solid content of the fluorocarbon coating liquid is preferably 58% to 65%.

The solid content of the fluorocarbon coating solution is limited to this range, which is beneficial to the uniform coating of the fluorocarbon layer on the surface of the substrate.

Further, the fluorocarbon resin may be one or more of polyvinylidene fluoride, polyvinyl fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene, and polyhexafluoropropylene.

The fluorocarbon resin utilizes the characteristics of high bond energy of fluorocarbon bonds, and can achieve the characteristics of weather resistance.

Further, the fluorocarbon resin is a thermosetting resin.

The fluorocarbon resin was provided by Daikin Fluorochemical.

Further, the UV absorber is an inorganic ceria nano-molecule with a particle size of 10-30 nm.

Generally, the thermal stability of organic UV absorbers is limited. Now the power of the components is getting bigger and bigger, and the heat is getting higher and higher under the strong current. There is a standard for modules called hot spot temperature. In the past, the hot spot temperature of general modules was only 130-140, and now large-sized modules can reach 170-180. The present invention utilizes cerium oxide as an inorganic UV absorber. Compared with organic UV absorbers, cerium oxide has the advantage of long-term stability, especially high temperature stability. Cerium oxide UV absorbers are used in transparent modules. At present, high-power photovoltaic cells are double-sided power generation modules, and a transparent backsheet must be used. The transparent backplane requires a suitable light transmittance. Large particle size UV absorbers will cause a decrease in light transmittance, but too small particles are easy to agglomerate during the coating process, and their performance is also unstable. Therefore, inorganic ceria nano-molecules The particle size is 10 to 30 nm.

Further, the matting powder is silica particles.

Further, the silica particles are provided by Grace.

Further, the added auxiliary is used to modify the fluorocarbon resin, and the added type is polyacrylate type.

The polyacrylate type described is mainly used to adjust the adhesive force after the weather resistance of the fluorocarbon coating.

The polyacrylate was supplied by BYK.

Further, the adhesion promoting resin is thermoplastic polyurethane resin.

The thermoplastic polyurethane resin is provided by Croda Chemical.

Further, the type of curing agent is of isocyanate type.

Further, the isocyanate can be a trimer or polymer of toluene diisocyanate, a trimer or polymer of hexamethylene diisocyanate, and a trimer or polymer of isophorone diisocyanate.

Further, the isocyanate is provided by Bayer.

Further, the fluorocarbon resin is selected from one or more of polyvinylidene fluoride, polyvinyl fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene, and polyhexafluoropropylene; the matting powder is silicon dioxide ; Described adhesion promoter is thermoplastic polyurethane resin with low acid value; Described additive is polyacrylate auxiliary agent; Described isocyanate is selected from toluene diisocyanate trimer or polymer, hexamethylene Diisocyanate trimers or polymers, or isophorone diisocyanate trimers or polymers.

The organic solvent is selected from one or a combination of at least two of ethyl acetate, butyl acetate, butanone, or cyclohexanone.

Further, the fluorocarbon coating solution contains 62%-70% of fluorocarbon resin, 5-7% of nano-cerium oxide, 2%-3% of matting powder, 0.4%-0.5% of polyacrylate, 12% of -14.6% thermoplastic polyurethane resin, 9.5%～13.6% isocyanate, control solid content at 58%～65%. The above technical solutions include Embodiments 1, 4, and 5.

Limiting the fluorocarbon coating formulation within the above-mentioned preferred parameters can ensure that the coating has high resistance to damp heat aging, and can still maintain high strength after damp heat aging, and can maintain the thermal stability of the coating under hot spot test conditions. sex.

The present invention also provides a solar back sheet, which sequentially comprises a transparent fluorocarbon coating, a base material, an adhesive layer, and a fluorine film layer. The transparent fluorocarbon coating includes fluorocarbon resin, UV absorber, matting powder, polyacrylate, low acid value thermoplastic polyurethane resin, isocyanate and the like.

Further, the substrate is a transparent substrate, and the material of the substrate layer is selected from polyethylene terephthalate (PET).

Further, the adhesive is a polyester adhesive.

Further, the fluorine film is a transparent PVF film or PVDF film.

The invention provides a fluorocarbon coating. The fluorocarbon coating comprises 50% to 80% of a fluorocarbon resin, 3% to 10% of an inorganic nano-cerium dioxide UV absorber, 1% to 5% by weight of the fluorocarbon coating. % of matting powder, 10% to 20% of adhesion promoter, 0.3% to 0.8% of additive ester, 5% to 20% of isocyanate. Further, the particle size of the inorganic ceria nanoparticles is 10-30 nm. Further, the fluorocarbon resin is selected from one or more of polyvinylidene fluoride, polyvinyl fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene, and polyhexafluoropropylene; the matting powder is silicon dioxide ; Described adhesion promoter is thermoplastic polyurethane resin with low acid value; Described additive is polyacrylate auxiliary agent; Described isocyanate is selected from toluene diisocyanate trimer or polymer, hexamethylene Diisocyanate trimers or polymers, or isophorone diisocyanate trimers or polymers.

Further, in the preparation process, the fluorocarbon coating material is first configured into a fluorocarbon coating solution, which contains 50% to 80% of fluorocarbon resin and 3% to 10% of inorganic nano-dioxide according to the weight percentage. Cerium oxide UV absorber, particle size is 10～30nm, 1%～5% matting powder, 10%～20% thermoplastic polyurethane adhesion promoter, 0.3%～0.8% polyacrylate, 5%～20% isocyanate, the solid content is controlled at 50% to 70%.

Further, the solar back sheet sequentially includes a transparent fluorocarbon coating, a substrate layer, a bonding adhesive layer (also referred to as an adhesive layer) and a fluorine film layer.

Further, the thickness of the transparent fluorocarbon coating is 10-20 μm; the thickness of the substrate layer is 250-300 μm, preferably 275-300 μm; the thickness of the adhesive layer is 6-10 μm; The thickness of the film layer is 20 to 25 μm.

Further, the thickness of the fluorocarbon layer is preferably 15-17 μm.

The transparent solar back sheet provided by the present invention can be used for the outermost back sheet encapsulation material of photovoltaic modules.

The preparation method of the solar back sheet provided by the present invention comprises the following steps:

First coat the transparent fluorocarbon coating solution on the surface of the substrate, and place it in a circulating oven for thermal curing to form a transparent fluorocarbon coating (referred to as fluorocarbon layer); then coat the other side of the substrate with an adhesive layer, place it on Dry in a circulating oven and attach the fluorine film layer; finally do a curing reaction.

Further, the drying temperature of the transparent fluorocarbon circulating oven is 150° C. and the time is 2 minutes.

Further, the drying temperature of the adhesive layer was 90° C. and the time was 2 minutes.

Further, the aging reaction temperature was 50°C, and the time was 48 hours.

Further, the base material is the model KP20 base material provided by Ningbo Qinbang. The substrate is also referred to as a PET substrate.

The above-mentioned coating process, thermal curing process, and laminating process can be set according to the prior art.

Before coating the fluorocarbon coating liquid on the surface of the substrate, the above preparation method further includes the step of preparing the raw material into the fluorocarbon coating liquid.

The fluorocarbon resin and nano-cerium oxide in the fluorocarbon coating solution provided by the present invention have an important influence on damp heat and UV aging properties, the added thermoplastic polyurethane plays an important role in the adhesion on the surface of transparent PET, and the added matting powder Coating processability plays an important role.

The fluorocarbon coating provided by the invention has achieved the following technical effects:

1. After the above-mentioned fluorocarbon coating liquid is cured into a fluorocarbon layer, the inner layer material of the solar back sheet that is resistant to aging and meets the encapsulation strength can be realized.

2. The cerium oxide nanoparticles used in the coating have good stability during the heat-spot test, which can meet the heat resistance and outdoor use effect of high-power components.

The solution provided by the present invention has the advantage of being sufficiently stable in heat resistance, and the fluorocarbon coating will not be consumed or damaged during the hot spot test.

Description of drawings

FIG. 1 is a schematic structural diagram of a solar back panel provided by the present invention.

Detailed ways

In order to more easily understand the structure of the present invention and the functional features and advantages that can be achieved, the preferred embodiments of the present invention are described below in detail with the drawings as follows:

As shown in FIG. 1 , the solar back sheet structure includes a transparent fluorocarbon coating 40 , a polyethylene terephthalate substrate 30 , a bonding adhesive layer 20 and a fluorine film layer 10 .

(1) Coat the transparent fluorocarbon coating solution on the surface of the substrate, and place it in a circulating oven for curing to form a transparent fluorocarbon layer; (2) Coat the other side of the semi-finished substrate coated with the fluorocarbon layer with an adhesive layer , the adhesive layer is placed in a circulating oven for drying, and then the fluorine film layer is compounded; (3) the finished solar back sheet is cured; (4) the fluorocarbon coating of the solar back sheet is laminated with EVA to simulate and test the packaging strength.

Further, (1) in the process, the drying temperature of the circulating oven for the treatment of the fluorocarbon layer is 150° C., and the time is 2 minutes;

Further, (2) the circulating oven temperature of the process adhesive drying is 90 ℃, and the time is 2 minutes;

Further, the aging treatment temperature in the process (3) was 50° C. and the time was 48 hours.

Further, the lamination parameters of the process (4) are suggested as temperature 145°C, vacuuming for 6 minutes, degassing for 30 seconds, lamination pressure 0.1 MPa, and lamination for 12 minutes.

Further, the laminated EVA of choice is F806 supplied by Foster.

Further, the selected base material is the model KP20 base material provided by Ningbo Qinbang. The substrate is also referred to as a PET substrate.

Before coating the fluorocarbon coating solution on the surface of the substrate, the above preparation method further includes the step of configuring the raw material of the fluorocarbon layer into the fluorocarbon coating solution.

The fluorocarbon coating provided by the present invention carries out the following tests:

Adhesion of fluorocarbon layer: According to the standard of GB 1720-1979 "Determination of Paint Film Adhesion", test the adhesion of fluorocarbon layer to the substrate, of which 100/100 means no peeling, 90/100 means 10% off .

Encapsulation strength test: According to the standard of GB/T 31034-2014 "Insulating Backplane for Crystalline Silicon Solar Cell Modules", the bonding strength of the inner fluorocarbon layer and EVA is tested, using the 180° peel force test method.

QUV aging treatment: According to the standard of GB/T 31034-2014 "Insulation Backplane for Crystalline Silicon Solar Cell Modules", it is treated with an ultraviolet aging lamp, and the accumulated ultraviolet energy reaches 120kwh/㎡, and the sample is taken out to observe the appearance.

Reflectivity: The reflectivity test is carried out according to the standard of GB/T 31034-2014 "Insulation Backsheet for Crystalline Silicon Solar Cell Modules".

Damp heat aging treatment: According to the standard of GB/T 31034-2014 "Insulating Backplane for Crystalline Silicon Solar Cell Modules", set the temperature in the high temperature and high humidity box to 85°C, the humidity to 85%, the accumulation time to be 2000h, take out the sample for observation Appearance and test package strength. After testing the encapsulation strength, observe the appearance of the fluorocarbon coating, and those with no yellowing or bulging are qualified (ie OK) (see the appearance of the hot spot test in Table 1).

The module hot spot test is tested according to the IEC61215 standard, and 78 cell modules with 182mm silicon wafers are selected for laboratory testing. The test conditions were 85° C., 85% humidity, and the power decay (power change data) was tested for 96h and 192h, respectively. The lower the power decay value, the better the anti-PID performance.

The fluorocarbon coating solution and the fluorocarbon layer provided by the present invention will be further described below with reference to the examples.

Example 1

The preparation method of the fluorocarbon coating solution provided in this embodiment includes:

70% polytetrafluoroethylene type fluorocarbon resin, 5% nano ceria UV absorber, particle size is 10～30nm, 3% matting powder, 0.5% polyacrylate additive, 12% thermoplastic polyurethane, 9.5% isocyanate. The host resin was dispersed in an organic solvent to form a fluorocarbon coating liquid with a solid content of 58%. Among them, the PTFE type fluorocarbon resin is provided by Daikin Fluorochemical, the nano ceria absorber is provided by BYK, the matting powder is provided by Grace Co., Ltd., the polyacrylate is provided by BYK, and the thermoplastic polyurethane is provided by He The isocyanate was provided by DaChem, the isocyanate was provided by Bayer, and the organic solvent was butyl acetate.

The coating was applied on transparent PET (275 μm thick) with a coating thickness of 16 μm.

The performance test results of the prepared fluorocarbon coatings are shown in Table 1.

Example 2

The preparation method of the fluorocarbon coating solution provided in this embodiment includes:

50% polytetrafluoroethylene type fluorocarbon resin, 10% nano ceria UV absorber, particle size is 10～30nm, 4% matting powder, 0.8% polyacrylate additive, 15.2% thermoplastic polyurethane, 20% isocyanate. The host resin was dispersed in an organic solvent to form a fluorocarbon coating liquid with a solid content of 50%. Among them, the PTFE type fluorocarbon resin is provided by Daikin Fluorochemical, the nano ceria absorber is provided by BYK, the matting powder is provided by Grace Co., Ltd., the polyacrylate is provided by BYK, and the thermoplastic polyurethane is provided by He The isocyanate was provided by DaChem, the isocyanate was provided by Bayer, and the organic solvent was butyl acetate.

The coating was applied on transparent PET (300 μm thick) with a coating thickness of 25 μm.

The performance test results of the prepared fluorocarbon coatings are shown in Table 1.

Example 3

The preparation method of the fluorocarbon coating solution provided in this embodiment includes:

80% polytetrafluoroethylene type fluorocarbon resin, 1.4% nano ceria UV absorber, particle size 10-30nm, 1% matting powder, 0.5% polyacrylate additive, 10% thermoplastic polyurethane, 7.1% isocyanate. The host resin was dispersed in an organic solvent to form a fluorocarbon coating liquid with a solid content of 70%. Among them, the PTFE type fluorocarbon resin is provided by Daikin Fluorochemical, the nano ceria absorber is provided by BYK, the matting powder is provided by Grace Co., Ltd., the polyacrylate is provided by BYK, and the thermoplastic polyurethane is provided by He The isocyanate was provided by DaChem, the isocyanate was provided by Bayer, and the organic solvent was butyl acetate.

The coating was applied on transparent PET (250 μm thick) with a coating thickness of 10 μm.

The performance test results of the prepared fluorocarbon coatings are shown in Table 1.

Example 4

The preparation method of the fluorocarbon coating solution provided in this embodiment includes:

65% polytetrafluoroethylene type fluorocarbon resin, 6% nano ceria UV absorber, particle size 10-30nm, 2% matting powder, 0.4% polyacrylate additive, 13% thermoplastic polyurethane, 13.6% isocyanate. The host resin was dispersed in an organic solvent to form a fluorocarbon coating liquid with a solid content of 62%. Among them, the PTFE type fluorocarbon resin is provided by Daikin Fluorochemical, the nano ceria absorber is provided by BYK, the matting powder is provided by Grace Co., Ltd., the polyacrylate is provided by BYK, and the thermoplastic polyurethane is provided by He The isocyanate was provided by DaChem, the isocyanate was provided by Bayer, and the organic solvent was butyl acetate.

The coating was applied on transparent PET (275 μm thick) with a coating thickness of 17 μm.

The performance test results of the prepared fluorocarbon coatings are shown in Table 1.

Example 5

The preparation method of the fluorocarbon coating solution provided in this embodiment includes:

62% polytetrafluoroethylene type fluorocarbon resin, 7% nano ceria UV absorber, particle size 10-30nm, 3% matting powder, 0.4% polyacrylate additive, 14.6% thermoplastic polyurethane, 13% isocyanate. The host resin was dispersed in an organic solvent to form a fluorocarbon coating liquid with a solid content of 65%. Among them, the PTFE type fluorocarbon resin is provided by Daikin Fluorochemical, the nano ceria absorber is provided by BYK, the matting powder is provided by Grace Co., Ltd., the polyacrylate is provided by BYK, and the thermoplastic polyurethane is provided by He The isocyanate was provided by DaChem, the isocyanate was provided by Bayer, and the organic solvent was butyl acetate.

The coating was applied on transparent PET (300 μm thick) with a coating thickness of 15 μm.

The performance test results of the prepared fluorocarbon coatings are shown in Table 1.

Example 6

The preparation method of the fluorocarbon coating solution provided in this embodiment includes:

55% polytetrafluoroethylene type fluorocarbon resin, 3% nano ceria UV absorber, particle size is 10～30nm, 4.5% matting powder, 0.3% polyacrylate additive, 20% thermoplastic polyurethane, 17.2% isocyanate. The host resin was dispersed in an organic solvent to form a fluorocarbon coating liquid with a solid content of 54%. Among them, the PTFE type fluorocarbon resin is provided by Daikin Fluorochemical, the nano ceria absorber is provided by BYK, the matting powder is provided by Grace Co., Ltd., the polyacrylate is provided by BYK, and the thermoplastic polyurethane is provided by He The isocyanate was provided by DaChem, the isocyanate was provided by Bayer, and the organic solvent was butyl acetate.

The coating was applied on transparent PET (300 μm thick) with a coating thickness of 22 μm.

The performance test results of the prepared fluorocarbon coatings are shown in Table 1.

Example 7

The preparation method of the fluorocarbon coating solution provided in this embodiment includes:

58% polytetrafluoroethylene type fluorocarbon resin, 9% nano ceria UV absorber, particle size 10-30nm, 4% matting powder, 0.3% polyacrylate additive, 16.4% thermoplastic polyurethane, 12.3% isocyanate. The host resin was dispersed in an organic solvent to form a fluorocarbon coating liquid with a solid content of 68%. Among them, the PTFE type fluorocarbon resin is provided by Daikin Fluorochemical, the nano ceria absorber is provided by BYK, the matting powder is provided by Grace Co., Ltd., the polyacrylate is provided by BYK, and the thermoplastic polyurethane is provided by He The isocyanate was provided by DaChem, the isocyanate was provided by Bayer, and the organic solvent was butyl acetate.

The coating was applied on transparent PET (300 μm thick) with a coating thickness of 20 μm.

The performance test results of the prepared fluorocarbon coatings are shown in Table 1.

Example 8

The preparation method of the fluorocarbon coating solution provided in this embodiment includes:

63.5% polytetrafluoroethylene type fluorocarbon resin, 7.8% nano ceria UV absorber, particle size 10～30nm, 5% matting powder, 0.7% polyacrylate additive, 18% thermoplastic polyurethane, 5% isocyanate. The host resin was dispersed in an organic solvent to form a fluorocarbon coating liquid with a solid content of 56%. Among them, the PTFE type fluorocarbon resin is provided by Daikin Fluorochemical, the nano ceria absorber is provided by BYK, the matting powder is provided by Grace Co., Ltd., the polyacrylate is provided by BYK, and the thermoplastic polyurethane is provided by He The isocyanate was provided by DaChem, the isocyanate was provided by Bayer, and the organic solvent was butyl acetate.

The coating was applied on transparent PET (275 μm thick) with a coating thickness of 16 μm.

The performance test results of the prepared fluorocarbon coatings are shown in Table 1.

Comparative Example 1

The preparation method of the fluorocarbon coating solution provided in this comparative example includes:

65% PTFE type fluorocarbon resin, 0% nano ceria UV absorber, 2% matting powder, 0.4% polyacrylate additive, 19% thermoplastic polyurethane, 13.6% isocyanate. The host resin was dispersed in an organic solvent to form a fluorocarbon coating liquid with a solid content of 62%. Among them, PTFE type fluorocarbon resin is provided by Daikin Fluorochemical, matting powder is provided by Grace Co., Ltd., polyacrylate is provided by BYK, thermoplastic polyurethane is provided by Croda Chemical, isocyanate is provided by Bayer, organic The solvent was butyl acetate.

The coating was applied on transparent PET (275 μm thick) with a coating thickness of 16 μm.

The performance test results of the prepared fluorocarbon coatings are shown in Table 1.

Comparative Example 2

The preparation method of the fluorocarbon coating solution provided in this comparative example includes:

50% polytetrafluoroethylene type fluorocarbon resin, 20% nano ceria UV absorber, particle size is 10～30nm, 2% matting powder, 0.4% polyacrylate additive, 14% thermoplastic polyurethane, 13.6% isocyanate. The host resin was dispersed in an organic solvent to form a fluorocarbon coating liquid with a solid content of 62%. Among them, the PTFE type fluorocarbon resin is provided by Daikin Fluorochemical, the nano ceria absorber is provided by BYK, the matting powder is provided by Grace Co., Ltd., the polyacrylate is provided by BYK, and the thermoplastic polyurethane is provided by He The isocyanate was provided by DaChem, the isocyanate was provided by Bayer, and the organic solvent was butyl acetate.

The coating was applied on transparent PET (275 μm thick) with a coating thickness of 16 μm.

The performance test results of the prepared fluorocarbon coatings are shown in Table 1.

Comparative Example 3

The preparation method of the fluorocarbon coating solution provided in this comparative example includes:

65% polytetrafluoroethylene type fluorocarbon resin, 6% nano ceria UV absorber, particle size 50～80nm, 2% matting powder, 0.4% polyacrylate additive, 13% thermoplastic polyurethane, 13.6% isocyanate. The host resin was dispersed in an organic solvent to form a fluorocarbon coating solution with a solid content of 62%. Among them, the PTFE type fluorocarbon resin is provided by Daikin Fluorochemical, the nano ceria absorber is provided by BYK, the matting powder is provided by Grace Co., Ltd., the polyacrylate is provided by BYK, and the thermoplastic polyurethane is provided by He The isocyanate was provided by DaChem, the isocyanate was provided by Bayer, and the organic solvent was butyl acetate.

The coating was applied on transparent PET (275 μm thick) with a coating thickness of 16 μm.

The performance test results of the prepared fluorocarbon coatings are shown in Table 1.

Comparative Example 4

The preparation method of the fluorocarbon coating solution provided in this comparative example includes:

65% PTFE type fluorocarbon resin, 6% nano ceria UV absorber, particle size 200nm, 2% matting powder, 0.4% polyacrylate additive, 13% thermoplastic polyurethane, 13.6% of isocyanates. The host resin was dispersed in an organic solvent to form a fluorocarbon coating liquid with a solid content of 62%. Among them, the PTFE type fluorocarbon resin is provided by Daikin Fluorochemical, the nano ceria absorber is provided by BYK, the matting powder is provided by Grace Co., Ltd., the polyacrylate is provided by BYK, and the thermoplastic polyurethane is provided by He The isocyanate was provided by DaChem, the isocyanate was provided by Bayer, and the organic solvent was butyl acetate.

The coating was applied on transparent PET (275 μm thick) with a coating thickness of 16 μm.

The performance test results of the prepared fluorocarbon coatings are shown in Table 1.

Comparative Example 5

The preparation method of the fluorocarbon coating solution provided in this comparative example includes:

65% polytetrafluoroethylene type fluorocarbon resin, 6% benzotriazole type UV absorber, 2% matting powder, 0.4% polyacrylate additive, 13% thermoplastic polyurethane, 13.6% isocyanate. The host resin was dispersed in an organic solvent to form a fluorocarbon coating liquid with a solid content of 62%. Among them, the PTFE type fluorocarbon resin is provided by Daikin Fluorochemical, the nano ceria absorber is provided by BYK, the matting powder is provided by Grace Co., Ltd., the polyacrylate is provided by BYK, and the thermoplastic polyurethane is provided by He The isocyanate was provided by DaChem, the isocyanate was provided by Bayer, and the organic solvent was butyl acetate.

The coating was applied on transparent PET (275 μm thick) with a coating thickness of 16 μm.

The performance test results of the prepared fluorocarbon coatings are shown in Table 1.

The fluorine films (fluorocarbon coating+substrate) in Examples 1 to 8 and Comparative Examples 1 to 5 were tested as follows: According to the standard of GB1720-1979 "Determination of Paint Film Adhesion", the fluorocarbon layer was tested. Adhesion, where 100/100 means no release, 90/100 means 10% shedding. According to the standard of JISK7105-1981 "Test method for optical properties of plastics", the total light transmittance of each fluorine film (fluorocarbon coating + substrate) was tested. According to the standard of GB/T 31034-2014 "Insulation Backsheet for Crystalline Silicon Solar Cell Modules", the packaging strength, humidity and heat aging resistance and QUV change of the solar backsheet are tested. The component hot spot performance is tested according to the IEC61215 standard.

Table 1 Test results of fluorine films (fluorocarbon coating + substrate) in Examples 1 to 8 and Comparative Examples 1 to 5

As can be seen from Table 1, when an organic benzotriazole UV absorber is used, the UV test performance is poor, and the photovoltaic module made of the back sheet is also prone to yellowing in appearance when testing the hot spot performance. This is because benzotriazole-type absorbents have poor high temperature resistance and are prone to molecular pyrolysis. The use of 50-80 nm cerium oxide will directly cause the transmittance of the transparent backplane to decrease. The use of larger particles of cerium oxide has adverse effects on both the damp heat test and the UV test. The above results show that nano-cerium oxide with suitable particle size has more advantages than organic small molecule UV absorbers in the effect of high temperature heat resistance, and can show advantages in the process of hot spot test of high-power components.

The fluorine film (fluorocarbon coating + base material) provided by the present invention can simultaneously ensure the encapsulation strength, damp-heat resistance, UV resistance and hot spot effect. Among them, the fluorocarbon film (fluorocarbon coating + substrate) provided in Examples 1, 4 and 5 has the best performance, the fluorocarbon layer does not fall off, the light transmittance exceeds 90%, and the initial encapsulation strength is at least 90N/cm. After the test of 120kwh/㎡, there is no obvious change in appearance. After the high humidity and heat aging test, the package strength is at least 60N/cm, and the appearance is qualified after the hot spot test.

The above descriptions are merely preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. All equivalent changes and modifications made according to the content of the present invention are covered within the patent scope of the present invention.

Claims (10)

1. The fluorocarbon coating liquid is characterized by comprising 50-80 wt% of fluorocarbon resin, 3-10 wt% of inorganic nano cerium dioxide UV absorbent, 1-5 wt% of matting powder, 10-20 wt% of adhesion promoter, 0.3-0.8 wt% of additive and 5-20 wt% of isocyanate.

2. A fluorocarbon coating liquid as claimed in claim 1, wherein said fluorocarbon resin is selected from one or more of polyvinylidene fluoride, polyvinyl fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene, polyhexafluoropropylene; the matting powder is silicon dioxide; the adhesion promoter is a thermoplastic polyurethane resin with a low acid value; the additive is a polyacrylate auxiliary agent; the isocyanate is selected from toluene diisocyanate trimer or polymer, hexamethylene diisocyanate trimer or polymer, or isophorone diisocyanate trimer or polymer.

3. A fluorocarbon coating liquid as set forth in claim 1 wherein said inorganic ceria nanoparticles have a particle size of 10 to 30 nm.

4. A fluorocarbon coating liquid as set forth in claim 1, characterized in that said fluorocarbon coating liquid has a solid content of 50% to 70%.

5. The fluorocarbon coating is characterized by comprising 50-80 wt% of fluorocarbon resin, 3-10 wt% of inorganic nano cerium dioxide UV absorbent, 1-5 wt% of matting powder, 10-20 wt% of adhesion promoter, 0.3-0.8 wt% of additive ester and 5-20 wt% of isocyanate.

6. A fluorocarbon coating according to claim 5, characterized in that the inorganic ceria nanoparticles have a particle size of 10-30 nm.

7. Fluorocarbon coating according to claim 5, characterized in that said fluorocarbon resin is selected from one or more of polyvinylidene fluoride, polyvinyl fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene, polyhexafluoropropylene; the matting powder is silicon dioxide; the adhesion promoter is a thermoplastic polyurethane resin with a low acid value; the additive is a polyacrylate auxiliary agent; the isocyanate is selected from toluene diisocyanate trimer or polymer, hexamethylene diisocyanate trimer or polymer, or isophorone diisocyanate trimer or polymer.

8. The solar backboard is characterized by comprising a transparent fluorocarbon coating, a poly (p-xylylene glycol) base material, a bonding glue layer and a fluorine film layer.

9. The solar back sheet according to claim 8, wherein the transparent fluorocarbon coating is formed by a fluorocarbon coating liquid, the fluorocarbon coating liquid comprises 50-80% of fluorocarbon resin, 3-10% of inorganic nano cerium dioxide UV absorber, 10-30 nm of particle size, 1-5% of matting powder, 10-20% of thermoplastic polyurethane adhesion promoter, 0.3-0.8% of polyacrylate and 5-20% of isocyanate in percentage by weight, and the solid content of the fluorocarbon coating liquid is 50-70%.

10. The solar back sheet according to claim 9, wherein the transparent fluorocarbon coating has a thickness of 10 to 20 μm; the thickness of the base material is 250-300 mu m; the thickness of the adhesive layer is 6-10 micrometers; the thickness of the fluorine film layer is 20-25 μm.

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