Fluorine-free coating and method for preparing the same, fluorine-free coating layer, photovoltaic backsheet, and photovoltaic device

Abstract

The application relates to a fluorine-free coating and a preparation method thereof, a fluorine-free coating layer, a photovoltaic backboard and a photovoltaic device. The fluorine-free coating comprises the following components in parts by mass: 30-50 parts of silicone resin; 20-30 parts of epoxy resin; 1-5 parts of isocyanate; and 5-10 parts of a rare earth ketone light conversion agent. The epoxy resin comprises an aliphatic glycidyl ether epoxy resin, and the isocyanate is an aliphatic diisocyanate. After the specific types of epoxy resin and silicone resin are combined with the specific type of isocyanate, the adhesion of the fluorine-free coating can be effectively improved, especially the adhesion strength of the fluorine-free coating to the PET substrate can be effectively improved, so that the problem that the silicone resin is easy to be powdered and the powder is dropped can be effectively solved. The rare earth ketone light conversion agent is combined with the silicone resin, the specific type of epoxy resin and the isocyanate, so that the rare earth ketone light conversion agent can effectively reflect the ultraviolet light into the air or convert the ultraviolet light into visible light, the photodegradation influence caused by the ultraviolet light is eliminated, and the aging resistance and weather resistance of the backboard are effectively prolonged.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to a fluorine-free coating and its preparation method, a fluorine-free coating layer, a photovoltaic backsheet, and a photovoltaic device. Background Technology

[0002] Solar photovoltaic (PV) modules are crucial for photoelectric conversion, while PV backsheets, as a key component protecting these modules, play an irreplaceable role due to their advantages such as light weight, reliable mechanical properties, superior weather resistance, and excellent insulation. Traditional CPC backsheets typically use fluorinated raw materials in their coatings to address UV photodegradation and improve weather resistance, thus extending the backsheet's lifespan. However, fluorinated materials cause environmental pollution, and the presence of fluorine in the product can affect the export of PV modules.

[0003] Therefore, it is necessary to improve traditional technologies. Summary of the Invention

[0004] Based on this, this application provides a fluorine-free coating with good weather resistance, a method for preparing the same, a fluorine-free coating, a photovoltaic backsheet, and a photovoltaic device.

[0005] The technical solution to the above-mentioned technical problems in this application is as follows.

[0006] The first aspect of this application provides a fluorine-free coating, comprising the following components by parts by weight:

[0007] 30-50 parts of silicone resin;

[0008] 20-30 parts epoxy resin;

[0009] 1-5 parts isocyanate; and

[0010] 5-10 parts of rare earth ketone-based optical conversion agent;

[0011] The epoxy resin includes aliphatic glycidyl ether epoxy resin, and the isocyanate is aliphatic diisocyanate.

[0012] In some embodiments, the fluorine-free coating comprises, by weight, the following components:

[0013] 40-45 parts of organosilicon resin;

[0014] 20-25 parts epoxy resin;

[0015] 3-5 parts isocyanate; and

[0016] 5-8 parts of rare earth ketone-based light-converting agent.

[0017] In some embodiments, the isocyanate in the fluorine-free coating includes at least one of hexamethylene diisocyanate and isoflurane diisocyanate.

[0018] In some embodiments, in the fluorine-free coating, the mass ratio of the silicone resin to the epoxy resin is (2~2.5):1.

[0019] In some embodiments, the rare earth ketone light-converting agent in the fluorine-free coating includes at least one of rare earth-α-thiophene trifluoroacetylacetone-o-phenanthroline complex, rare earth-2-octyl-1,3-diphenyl-1,3-propanedione-o-phenanthroline complex, and rare earth-3-allyl-2,4-pentanedione-o-phenanthroline complex.

[0020] In some embodiments, the fluorine-free coating further includes 5 to 15 parts by weight of a silane coupling agent.

[0021] In some embodiments, the silane coupling agent in the fluorine-free coating includes at least one of vinyltriethoxysilane, vinyltrimethoxysilane, and vinylmethoxyethoxysilane.

[0022] In some embodiments, the fluorine-free coating further includes 1 to 5 parts by weight of a matting agent.

[0023] In some embodiments, the matting agent in the fluorine-free coating includes at least one of polyacrylamide, aluminum stearate, calcium stearate, silica, and talc.

[0024] The second aspect of this application provides a method for preparing a fluorine-free coating, comprising the following steps:

[0025] By weight, 30-50 parts of silicone resin, 20-30 parts of epoxy resin, 1-5 parts of isocyanate and 5-10 parts of rare earth ketone light-converting agent are mixed to prepare a fluorine-free coating; wherein the epoxy resin includes aliphatic glycidyl ether epoxy resin and the isocyanate is aliphatic diisocyanate.

[0026] The third aspect of this application provides a fluorine-free coating, which is formed by curing a fluorine-free coating prepared using the fluorine-free coating provided in the first aspect or the preparation method provided in the second aspect.

[0027] The fourth aspect of this application provides a photovoltaic backsheet, including a substrate and a fluorine-free coating provided in the third aspect disposed on at least one surface of the substrate.

[0028] The fifth aspect of this application provides a photovoltaic device, including the photovoltaic backsheet provided in the fourth aspect.

[0029] Compared with existing technologies, the fluorine-free coating of this application has the following beneficial effects:

[0030] The fluorine-free coating of this application includes silicone resin, epoxy resin, isocyanate, and rare earth ketone light-converting agent. By combining fluorine-free silicone resin with a specific type of epoxy resin, the curing temperature of the fluorine-free coating can be effectively reduced, and the mechanical and abrasion resistance of the resulting fluorine-free coating can be effectively improved, while also being environmentally friendly. Simultaneously, the interaction of the specific type of epoxy resin and silicone resin with a specific type of isocyanate can effectively improve the adhesion of the fluorine-free coating, especially the adhesion strength to PET substrates, thereby effectively solving the problem of silicone resin easily turning powdery. To address the issue of powdering, rare earth ketone light-converting agents are combined with silicone resins, specific types of epoxy resins, and isocyanates. The rare earth ketones form hydrogen bonds and other chemical bonds with the isocyanates, effectively preventing the migration and precipitation of the rare earth ketones. Simultaneously, the epoxy resin stabilizes and cures the dispersed rare earth ketones, effectively promoting uniform dispersion of the rare earth ketones in the fluorine-free coating. This effectively allows the rare earth ketones to reflect ultraviolet light into the air or convert it into visible light, eliminating the photodegradation caused by ultraviolet light and preventing yellowing. This, in turn, effectively extends the aging and weather resistance of the backing panel. Detailed Implementation

[0031] Reference will now be made to detailed embodiments of the present invention, one or more of which are described below. Each example is provided for explanation and not for limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the invention without departing from its scope or spirit. For example, features described or illustrated as part of one embodiment may be used in another embodiment to produce further embodiments.

[0032] Therefore, this invention is intended to cover such modifications and variations falling within the scope of the appended claims and their equivalents. Other objects, features, and aspects of the invention are disclosed in or will be apparent from the following detailed description. It will be understood by those skilled in the art that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of the invention.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0034] The terms “comprising,” “including,” or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element preceded by the phrase “comprising one…” does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. The indefinite articles “a” and “an” preceding an element or component of the invention are not restrictive in terms of the number of elements or components (i.e., the number of times they appear). Therefore, “an” or “an” should be interpreted as including one or at least one, and singular elements or components also include plural forms, unless the quantity clearly refers only to the singular. “A plurality” means at least two, such as two, three, etc., unless otherwise expressly specified.

[0035] The weights of the relevant components mentioned in the embodiments of this invention can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this invention is within the scope disclosed in the embodiments of this invention. Specifically, the weights mentioned in the embodiments of this invention can be well-known units of mass in the chemical industry, such as μg, mg, g, and kg.

[0036] Unless otherwise shown or indicated in the operational embodiments, all figures used to represent the amounts, physicochemical properties, etc., of ingredients in the specification and claims are to be understood to be adjusted by the term "about" in all cases. For example, therefore, unless stated to the contrary, the numerical parameters listed in the foregoing specification and appended claims are approximations, and those skilled in the art can appropriately modify these approximations to obtain the desired characteristics by utilizing the teachings disclosed herein. The use of numerical ranges indicated by endpoints includes all numbers within that range and any range within that range; for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4, and 5, etc.

[0037] One embodiment of this application provides a fluorine-free coating, comprising the following components by mass parts:

[0038] 30-50 parts of silicone resin;

[0039] 20-30 parts epoxy resin;

[0040] 1-5 parts isocyanate; and

[0041] 5-10 parts of rare earth ketone-based optical conversion agent;

[0042] Epoxy resins include aliphatic glycidyl ether epoxy resins, and isocyanates are aliphatic diisocyanates.

[0043] It is understandable that silicone resins and epoxy resins do not contain fluorine atoms.

[0044] The fluorine-free coating of this application includes silicone resin, epoxy resin, isocyanate, and rare earth ketone light-converting agent. By combining fluorine-free silicone resin with a specific type of epoxy resin, the curing temperature of the fluorine-free coating can be effectively reduced, and the mechanical and abrasion resistance of the resulting fluorine-free coating can be effectively improved, while also being environmentally friendly. Simultaneously, the interaction of the specific type of epoxy resin and silicone resin with a specific type of isocyanate can effectively improve the adhesion of the fluorine-free coating, especially the adhesion strength to PET substrates, thereby effectively solving the problem of silicone resin easily turning powdery. To address the issue of powdering, rare earth ketone light-converting agents are combined with silicone resins, specific types of epoxy resins, and isocyanates. The rare earth ketones form hydrogen bonds and other chemical bonds with the isocyanates, effectively preventing the migration and precipitation of the rare earth ketones. Simultaneously, the epoxy resin stabilizes and cures the dispersed rare earth ketones, effectively promoting uniform dispersion of the rare earth ketones in the fluorine-free coating. This effectively allows the rare earth ketones to reflect ultraviolet light into the air or convert it into visible light, eliminating the photodegradation caused by ultraviolet light and preventing yellowing. This, in turn, effectively extends the aging and weather resistance of the backing panel.

[0045] The fluorine-free coating provided by this invention has good thermal stability, insulation, weather resistance and mechanical properties due to the synergistic effect of its components. It can improve the weather resistance of the backing plate and reduce the coating cost.

[0046] Studies have shown that when specific types of aliphatic diisocyanates are used, the coating formed by this fluorine-free paint will not yellow under light. If yellowing does occur, the molecular weight changes, leading to a decrease in weather resistance.

[0047] It is understood that, by weight parts, silicone resin includes, but is not limited to, 30 parts, 32 parts, 35 parts, 38 parts, 40 parts, 42 parts, 45 parts, 48 ​​parts, and 50 parts; epoxy resin includes, but is not limited to, 20 parts, 22 parts, 25 parts, 28 parts, and 30 parts; isocyanate includes, but is not limited to, 1 part, 2 parts, 3 parts, 4 parts, and 5 parts; and rare earth ketone light conversion agents include, but are not limited to, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, and 10 parts. In some examples, any two of these point values ​​can be used as endpoints within a range, and the same applies below.

[0048] In some of these examples, the fluorine-free coatings comprise, by weight, the following components:

[0049] 40-45 parts of organosilicon resin;

[0050] 20-25 parts epoxy resin;

[0051] 3-5 parts isocyanate; and

[0052] 5-8 parts of rare earth ketone-based light-converting agent.

[0053] In some of these examples, the fluorine-free coatings comprise, by weight, the following components:

[0054] 42-45 parts of organosilicon resin;

[0055] 20-22 parts epoxy resin;

[0056] 4-5 parts isocyanate; and

[0057] 5-8 parts of rare earth ketone-based light-converting agent.

[0058] In some of these examples, the isocyanate in the fluorine-free coating includes at least one of hexamethylene diisocyanate (HMDI) and isoflurone diisocyanate (IPDI).

[0059] It is understandable that aliphatic glycidyl ether epoxy resins will hydrolyze to form diols during the reaction. Taking hexamethylene diisocyanate as an example, the reaction includes the following:

[0060]

[0061] It is understood that silicone resins include, but are not limited to, at least one of polymethyl silicone resin, polyethyl silicone resin, polyaryl silicone resin, polyalkylaryl silicone resin, methyl silicone resin, methylphenyl silicone resin, and MQ silicone resin.

[0062] In some of these examples, the mass ratio of silicone resin to epoxy resin in the fluorine-free coating is (2~2.5):1.

[0063] It is understood that the mass ratio of silicone resin to epoxy resin includes, but is not limited to, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, and 2.5:1.

[0064] In some of these examples, the rare earth ketone light-converting agents in the fluorine-free coatings include at least one of the following: rare earth-α-thiophene trifluoroacetylacetone-o-phenanthroline complex, rare earth-2-octyl-1,3-diphenyl-1,3-propanedione-o-phenanthroline complex, and rare earth-3-allyl-2,4-pentanedione-o-phenanthroline complex.

[0065] Furthermore, the rare earth elements in rare earth ketone light-converting agents include, but are not limited to, at least one of samarium (Sm), europium (Eu), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), and thulium (Tm).

[0066] In some of these examples, the rare earth ketone light-converting agents in the fluorine-free coatings include at least one of samarium-3-allyl-2,4-pentanedione-o-phenanthroline complex, europium-3-allyl-2,4-pentanedione-o-phenanthroline complex, etc.

[0067] It is understood that the fluorine-free coatings provided in this application may also include at least one of commonly used additives in the art, such as dispersants, matting agents, thickeners, antioxidants, leveling agents, and defoamers. Further, common types of dispersants mainly include polymer dispersants, small organic molecule dispersants, mineral oil dispersants, and surfactant dispersants. Defoamers include, but are not limited to, at least one of polydimethylsiloxane, fluorosiloxane, ethylene glycol siloxane, and polyether defoamers.

[0068] In some of these examples, the dispersant includes, but is not limited to, silane coupling agents, such as at least one of tetraethyl silicate, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and vinyltri(2-methoxyethoxy)silane.

[0069] In some of these examples, the fluorine-free coatings also include 5 to 15 parts by weight of silane coupling agent.

[0070] It is understandable that, by mass percentage, the silane coupling agent in fluorine-free coatings includes, but is not limited to, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, and 10 parts.

[0071] In some of these examples, the silane coupling agent in the fluorine-free coating includes at least one of vinyltriethoxysilane, vinyltrimethoxysilane, and vinylmethoxyethoxysilane.

[0072] In some of these examples, the fluorine-free coatings also include 1 to 5 parts by weight of matting agent.

[0073] It is understandable that, by weight, the matting agent in fluorine-free coatings includes, but is not limited to, 1 part, 2 parts, 3 parts, 4 parts, and 5 parts.

[0074] In some of these examples, the matting agent in the fluorine-free coating includes at least one of polyacrylamide, aluminum stearate, calcium stearate, silica, and talc.

[0075] One embodiment of this application provides a method for preparing a fluorine-free coating, comprising the following steps:

[0076] By weight, 30-50 parts of silicone resin, 20-30 parts of epoxy resin, 1-5 parts of isocyanate and 5-10 parts of rare earth ketone light-converting agent are mixed to prepare a fluorine-free coating; the epoxy resin includes aliphatic glycidyl ether epoxy resin and the isocyanate is aliphatic diisocyanate.

[0077] It is understood that the preparation method of the fluorine-free coating provided in this application can prepare the above-mentioned fluorine-free coating, and the above-mentioned fluorine-free coating can be obtained by the preparation method of the fluorine-free coating provided in this application; further, it is understood that the technical features of the above-mentioned fluorine-free coating are applicable to the preparation method of the fluorine-free coating.

[0078] The fluorine-free coating prepared by the method provided in this application has good adhesion and weather resistance.

[0079] One embodiment of this application provides a fluorine-free coating, which is formed by curing a fluorine-free coating prepared by the above-described fluorine-free paint or the above-described preparation method.

[0080] It is understood that the fluorine-free coating provided in this application is formed by curing the fluorine-free coating prepared by the above-mentioned fluorine-free coating or the fluorine-free coating prepared by the above-mentioned preparation method, and has the advantages of the fluorine-free coating prepared by the above-mentioned fluorine-free coating or the fluorine-free coating prepared by the above-mentioned preparation method.

[0081] One embodiment of this application provides the application of the above-described fluorine-free coating in the preparation of photovoltaic backsheets.

[0082] Another embodiment of this application provides a photovoltaic backsheet, including a substrate and a fluorine-free coating disposed on at least one surface of the substrate.

[0083] Applying the aforementioned fluorine-free coating to the substrate can effectively improve the weather resistance of photovoltaic backsheets.

[0084] It is understandable that a fluorine-free coating can be applied to both surfaces of the substrate, or only to one surface of the substrate.

[0085] In some of these examples, the substrate in the photovoltaic backsheet includes, but is not limited to, at least one of PET substrate, PE substrate, PP substrate and PA substrate.

[0086] In some of these examples, the thickness of the substrate in the photovoltaic backsheet is 250 mm to 300 mm.

[0087] It is understood that the thickness of the substrate includes, but is not limited to, 250 mm, 260 mm, 270 mm, 275 mm, 280 mm, 285 mm, 290 mm, and 300 mm.

[0088] One embodiment of this application provides a method for preparing a photovoltaic backsheet, comprising the following steps:

[0089] The above-mentioned fluorine-free coating or the fluorine-free coating prepared by the above preparation method is applied to at least one surface of the substrate, and after curing, a fluorine-free coating is formed on the surface of the substrate.

[0090] In some of these examples, the curing temperature in the photovoltaic backsheet preparation method is 140℃~170℃, and the time is 2h~6h.

[0091] It is understood that the curing temperature includes, but is not limited to, 140℃, 145℃, 150℃, 155℃, 160℃, and 170℃, and the time includes, but is not limited to, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, and 6 h.

[0092] In some examples, the method of preparing a photovoltaic backsheet involves applying a fluorine-free coating to the surface of the substrate, including but not limited to one of the following: extrusion coating, anilox coating, blade coating, spraying, inkjet printing, or transfer printing.

[0093] In some of these examples, the method for preparing a photovoltaic backsheet includes a step of corona treatment of the substrate before the step of applying a fluorine-free coating to the substrate surface.

[0094] In some of these examples, the method for preparing a photovoltaic backsheet includes, after the curing step, steps of aging and winding the resulting material.

[0095] One embodiment of this application provides a photovoltaic device, including the photovoltaic backsheet described above or the photovoltaic backsheet prepared by the above method.

[0096] The photovoltaic device provided in this application has at least the same advantages as the photovoltaic backsheet or the photovoltaic backsheet prepared by the above-mentioned preparation method because it has the photovoltaic backsheet or the photovoltaic backsheet prepared by the above-mentioned preparation method.

[0097] The present application will be described in further detail below with reference to specific embodiments, but the embodiments of the present application are not limited thereto.

[0098] Example 1

[0099] Raw materials provided: by weight, 40 parts methyl silicone resin (organic silicone resin), 20 parts aliphatic glycidyl ether epoxy resin, 5 parts hexamethylene diisocyanate, 5 parts europium-3-allyl-2,4-pentanedione-o-phenanthroline complex (rare earth ketone light conversion agent), 15 parts vinyltriethoxysilane (silane coupling agent), and 5 parts polyacrylamide; the mass ratio of organic silicone resin to epoxy resin is 2:1.

[0100] Organosilicon resin, aliphatic glycidyl ether epoxy resin, hexamethylene diisocyanate, rare earth ketone light conversion agent, silane coupling agent and polyacrylamide are mixed, 50 parts of solvent are added, and the mixture is stirred and reacted at 60℃~120℃ for 2~4 hours. No particulate matter is found in the reactor, thus obtaining a fluorine-free coating.

[0101] Example 2

[0102] The process is essentially the same as in Example 1, except that the components or proportions in the fluorine-free coating differ by mass, as detailed below:

[0103] By mass fraction, the composition includes 45 parts methyl silicone resin, 20 parts aliphatic glycidyl ether epoxy resin, 5 parts hexamethylene diisocyanate, 5 parts europium-3-allyl-2,4-pentanedione-o-phenanthroline complex, 15 parts vinyltriethoxysilane, and 5 parts polyacrylamide; the mass ratio of silicone resin to epoxy resin is 2.25:1.

[0104] Example 3

[0105] The process is essentially the same as in Example 1, except that the components or proportions in the fluorine-free coating differ by mass, as detailed below:

[0106] By mass fraction, the composition includes 50 parts methyl silicone resin, 20 parts aliphatic glycidyl ether epoxy resin, 5 parts hexamethylene diisocyanate, 5 parts europium-3-allyl-2,4-pentanedione-o-phenanthroline complex, 15 parts vinyltriethoxysilane, and 5 parts polyacrylamide; the mass ratio of silicone resin to epoxy resin is 2.5:1.

[0107] Example 4

[0108] The process is essentially the same as in Example 1, except that the components or proportions in the fluorine-free coating differ by mass, as detailed below:

[0109] By mass fraction, the composition includes 45 parts methyl silicone resin, 20 parts aliphatic glycidyl ether epoxy resin, 5 parts hexamethylene diisocyanate, 8 parts europium-3-allyl-2,4-pentanedione-o-phenanthroline complex, 15 parts vinyltriethoxysilane, and 5 parts polyacrylamide; the mass ratio of silicone resin to epoxy resin is 2.25:1.

[0110] Example 5

[0111] The process is essentially the same as in Example 1, except that the components or proportions in the fluorine-free coating differ by mass, as detailed below:

[0112] By mass fraction, the composition includes 45 parts methyl silicone resin, 20 parts aliphatic glycidyl ether epoxy resin, 5 parts hexamethylene diisocyanate, 10 parts europium-3-allyl-2,4-pentanedione-o-phenanthroline complex, 15 parts vinyltriethoxysilane, and 5 parts polyacrylamide; the mass ratio of silicone resin to epoxy resin is 2.25:1.

[0113] Comparative Example 1

[0114] The comparison is basically the same as Example 1, except that the silicone resin in Example 1 is replaced with an equal mass of polyolefin resin.

[0115] Comparative Example 2

[0116] The comparison is basically the same as Example 1, except that the epoxy resin in Example 1 is replaced with an equal mass of terpene resin in Comparative Example 2.

[0117] Comparative Example 3

[0118] The comparison is basically the same as Example 1, except that the aliphatic glycidyl ether epoxy resin in Example 1 is replaced with an equal mass of bisphenol A type epoxy resin in Comparative Example 3.

[0119] Comparative Example 4

[0120] The comparison example is basically the same as Example 1, except that the aliphatic glycidyl ether epoxy resin in Example 1 is replaced with an equal mass of bisphenol F type epoxy resin in Comparative Example 4.

[0121] Comparative Example 5

[0122] The comparison is basically the same as Example 1, except that the aliphatic glycidyl ether epoxy resin in Example 1 is replaced with an equal mass of glycidyl amine epoxy resin in Comparative Example 5.

[0123] Comparative Example 6

[0124] The comparison is basically the same as Example 1, except that the aliphatic glycidyl ether epoxy resin in Example 1 is replaced with an equal mass of glycidyl ester type epoxy resin in Comparative Example 6.

[0125] Comparative Example 7

[0126] This is basically the same as Example 1, except that the proportions of the components in the fluorine-free coating are different, as detailed below:

[0127] By mass, the composition includes 20 parts of silicone resin, 50 parts of aliphatic glycidyl ether epoxy resin, 5 parts of hexamethylene diisocyanate, 5 parts of europium-3-allyl-2,4-pentanedione-o-phenanthroline complex, 15 parts of vinyltriethoxysilane (silane coupling agent), and 5 parts of polyacrylamide; the mass ratio of silicone resin to epoxy resin is 0.4:1.

[0128] Comparative Example 8

[0129] The comparison is basically the same as Example 1, except that in Comparative Example 8, the hexamethylene diisocyanate in Example 1 is replaced with an equal mass of diphenylmethane diisocyanate.

[0130] A PET substrate is provided, which has been corona treated; the fluorine-free coatings prepared in each embodiment and comparative example are respectively coated on the surface of the PET substrate and dried and cured at 150°C to obtain a light-converting fluorine-free backsheet.

[0131] The light-converting fluorine-free backsheets coated with each embodiment and comparative example were subjected to cross-cut adhesion test, UVDH aging test, and UV test, with the test standards referring to IEC61215 & 61730; the test results are shown in Table 1.

[0132] Table 1

[0133]

[0134] As can be seen from Table 1, compared with the comparative examples, the fluorine-free coatings prepared in the examples have better weather resistance. However, comparative examples 1 and 2, which replaced polyolefin resin and terpene resin respectively, will yellow under strong ultraviolet irradiation, reduce weather resistance, and crack when used at -40℃ to 80℃. In comparative examples 3 to 5, the aliphatic glycidyl ether epoxy resin was replaced with equal masses of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and glycidyl ester type epoxy resin respectively. Under ultraviolet irradiation, the yellowing was severe, affecting the appearance, reducing weather resistance, and shortening the service life. In comparative example 6, glycidyl ester type epoxy resin was used, which reduced weather resistance. In comparative example 7, which was mainly epoxy resin, the weather resistance was not satisfactory, and the coating was brittle and its mechanical properties were reduced.

[0135] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0136] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A fluorine-free coating, characterized in that, By mass, it includes the following components: 30-45 parts of silicone resin; 20-30 parts epoxy resin; 1-5 parts isocyanate; and 5-9 parts of rare earth ketone-based optical conversion agent; The epoxy resin is an aliphatic glycidyl ether epoxy resin, and the isocyanate is an aliphatic diisocyanate.

2. The fluorine-free coating as described in claim 1, characterized in that, By mass, it includes the following components: 40-45 parts of organosilicon resin; 20-25 parts epoxy resin; 3-5 parts isocyanate; and 5-8 parts of rare earth ketone-based light-converting agent.

3. The fluorine-free coating as described in claim 1, characterized in that, The isocyanate includes at least one of hexamethylene diisocyanate and isoflurone diisocyanate.

4. The fluorine-free coating as described in claim 1, characterized in that, The mass ratio of the silicone resin to the epoxy resin is (2~2.25):

1.

5. The fluorine-free coating as described in claim 1, characterized in that, The rare earth ketone-based light-converting agents include at least one of the following: rare earth-α-thiophene trifluoroacetylacetone-phenanthroline complex, rare earth-2-octyl-1,3-diphenyl-1,3-propanedione-phenanthroline complex, and rare earth-3-allyl-2,4-pentanedione-phenanthroline complex.

6. The fluorine-free coating according to any one of claims 1 to 5, characterized in that, The fluorine-free coating also includes 5 to 15 parts of silane coupling agent by weight.

7. The fluorine-free coating as described in claim 6, characterized in that, The silane coupling agent includes at least one of vinyltriethoxysilane, vinyltrimethoxysilane, and vinylmethoxyethoxysilane.

8. The fluorine-free coating according to any one of claims 1 to 5 and 7, characterized in that, The fluorine-free coating also includes 1 to 5 parts of matting agent by weight.

9. The fluorine-free coating as described in claim 8, characterized in that, The matting agent includes at least one of polyacrylamide, aluminum stearate, calcium stearate, silica, and talc.

10. A method for preparing a fluorine-free coating, characterized in that, Includes the following steps: By weight, 30-45 parts of silicone resin, 20-30 parts of epoxy resin, 1-5 parts of isocyanate and 5-9 parts of rare earth ketone light-converting agent are mixed to prepare a fluorine-free coating; wherein the epoxy resin is an aliphatic glycidyl ether epoxy resin and the isocyanate is an aliphatic diisocyanate.

11. A fluorine-free coating, characterized in that, The fluorine-free coating is formed by curing the fluorine-free coating obtained by any one of claims 1 to 9 or by the preparation method described in claim 10.

12. A photovoltaic backsheet, characterized in that, It includes a substrate and a fluorine-free coating as described in claim 11 disposed on at least one surface of the substrate.

13. A photovoltaic device, characterized in that, Including the photovoltaic backsheet as described in claim 12.

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