Packaging adhesive film and solar photovoltaic module

Abstract

The invention provides a packaging adhesive film and a solar photovoltaic module, and belongs to the technical field of photoelectricity. The packaging adhesive film is prepared from the following raw materials in parts by mass: vinyl resin, an ultraviolet light conversion agent and an ultraviolet light absorption agent, the structural formula of the ultraviolet light conversion agent is as shown in formula I, R4 and R6 are independently selected from any one of C1-C20 alkyl, C3-C20 alkyl with at least one methylene substituted by-NHCOO-, and substituted or unsubstituted C2-C20 alkenyl, and R5 is selected from C3-C20 alkyl substituted by at least one of epoxy group,-OH and-NCO; functional groups in the ultraviolet light absorber comprise at least one of vinyl, acrylic acid group, methacrylic acid group, carboxyl, epoxy group, acyl chloride group and isocyanate group. By using the packaging adhesive film, a corresponding photovoltaic module can have high module power for a long time.

Description

Technical Field

[0001] The present application relates to the field of optoelectronic technology, and in particular to a packaging film and a solar photovoltaic module. Background Art

[0002] As one of the main renewable energy sources, solar energy has the characteristics of wide sources, clean and harmless, and sustainable. The energy of solar radiation is mainly concentrated between the wavelength of 0.15 and 4 microns. This wavelength range can be divided into three main regions, namely the ultraviolet region with a shorter wavelength, the infrared region with a longer wavelength, and the visible region between the two. The energy of solar radiation is mainly distributed in the visible light region and the infrared region, the former accounting for 50% of the total solar radiation, and the latter accounting for 43%. Although the ultraviolet region accounts for only 7% of the total solar radiation energy, ultraviolet light has a high penetrating power, which will cause ultraviolet light decay of photovoltaic modules (for example, under the irradiation of ultraviolet light, the transmittance of dye-sensitized solar photovoltaic modules will decrease, and the silicon-hydrogen bonds in the heterojunction cell structure are easily destroyed by ultraviolet light), which will affect the power of the corresponding solar photovoltaic modules. Summary of the invention

[0003] The purpose of the present application is to provide a packaging film and a solar photovoltaic module. The use of the packaging film can enable the corresponding photovoltaic module to have a higher module power for a long time.

[0004] The embodiment of the present application is implemented as follows:

[0005] In a first aspect, an embodiment of the present application provides a packaging film. The raw materials for preparing the packaging film include a vinyl resin, an ultraviolet light conversion agent, and an ultraviolet light absorber in terms of weight fraction. The structural formula of the ultraviolet light conversion agent is shown in Formula I:

[0006]

[0007] Wherein, R4 and R6 are independently selected from any one of a C1-C20 alkyl group, a C3-C20 alkyl group in which at least one methylene group is substituted by -NHCOO-, and a substituted or unsubstituted C2-C20 alkenyl group; R5 is selected from a C3-C20 hydrocarbon group substituted by at least one of an epoxy group, -OH and -NCO; and the functional groups in the ultraviolet absorber include at least one of a vinyl group, an acrylic group, a methacrylic group, a carboxyl group, an epoxy group, an acyl chloride group and an isocyanate group.

[0008] In the above technical solution, the raw materials for preparing the encapsulation film contain both a UV converter with a specific structure and a UV absorber with a specific structure. On the one hand, the encapsulation film contains a UV converter with a specific structure, which can convert UV light into visible light that can be used by solar photovoltaic modules, thereby helping to improve the module power of the photovoltaic module; and the UV converter with a specific structure can also be stably grafted with the polymer matrix (mainly achieved through the R5 group in the structure), so that the photovoltaic module can have a high module power for a long time. On the other hand, the encapsulation film also contains a UV absorber with a specific structure, which can absorb the residual UV light that has not been converted (that is, it can effectively protect the photovoltaic module), thereby effectively solving the problem of poor module power caused by module light decay; and the UV absorber with a specific structure can also be stably grafted with the polymer matrix, so as to be able to protect the photovoltaic module for a long time and continuously (if the UV absorber cannot be grafted with the polymer matrix, it is easy to migrate during use, resulting in a reduced concentration and uneven distribution, making it difficult to effectively protect the photovoltaic module for a long time). Through the combined effect of these two aspects, the encapsulation film can convert most of the difficult-to-use and harmful ultraviolet light into usable visible light, and the remaining small amount of ultraviolet light can also be absorbed by it without affecting the photovoltaic modules. In addition, the ultraviolet converter and ultraviolet absorber in the encapsulation film can function stably for a long time, so that the photovoltaic modules using the encapsulation film can have a higher module power for a long time.

[0009] In some optional embodiments, R4 and R6 are each independently selected from any one of a C1-C10 alkyl group, a C3-C10 alkyl group in which at least one methylene group is substituted by -NHCOO-, and a substituted or unsubstituted C2-C10 alkenyl group; and / or, R5 is selected from a C3-C10 hydrocarbon group substituted by at least one of an epoxy group, -OH and -NCO.

[0010] In the above technical solution, R4~R6 are further limited to a specific range so that the ultraviolet converter can more effectively convert ultraviolet light into visible light. At the same time, it can also improve its grafting rate with the polymer matrix and the stability after grafting. In addition, it can also reduce the preparation cost of the corresponding packaging film.

[0011] In some optional embodiments, R5 further contains -NHCOO- and / or -CO-.

[0012] In the above technical solution, -NHCOO- and -CO- have a certain catalytic effect. The presence of the two helps the ultraviolet light conversion agent and the polymer matrix to be grafted more easily, thereby improving the grafting efficiency and the stability after grafting.

[0013] In some optional embodiments, the ultraviolet light absorber is selected from at least one of substituted triazine ultraviolet light absorbers, benzophenone ultraviolet light absorbers, salicylate ultraviolet light absorbers, benzotriazole ultraviolet light absorbers and substituted acrylonitrile ultraviolet light absorbers.

[0014] In the above technical solutions, the applicable types of ultraviolet absorbers are relatively rich, and more feasible implementation plans can be provided, thereby facilitating the promotion and application of the technical solutions provided in this application.

[0015] In some optional embodiments, the ultraviolet absorber is selected from at least one of 3-benzoyl-4-hydroxybenzoic acid, 3-(3-(2H-benzo[d][1,2,3]triazol-2-yl)-5-(tert-butyl)-4-hydroxyphenyl)propionyl chloride, 4-(4,6-bis(2-hydroxyphenyl)-1,3,5-triazine-2-yl)benzoic acid, 3-(2-benzotriazolyl)-4-hydroxy-5-tert-butylbenzenepropionic acid, 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 2-acrylic acid-2-(4-benzoyl-3-hydroxyphenoxy)ethyl ester and 2-(2'-hydroxy-3'-allyl-5'-methylphenyl)-2H-benzotriazole.

[0016] In the above technical solution, the specific type of ultraviolet absorber has the advantages of good ultraviolet light absorption effect and easy acquisition.

[0017] In some optional embodiments, the vinyl resin is selected from at least one of polyethylene, copolymers of ethylene and 1-butene, copolymers of ethylene and 1-octene, copolymers of ethylene and propylene, copolymers of ethylene and vinyl acetate, copolymers of ethylene and acrylic acid, copolymers of ethylene and maleic anhydride, and copolymers of ethylene and glycidyl methacrylate.

[0018] In the above technical scheme, the applicable types of vinyl resins are relatively rich, and more feasible implementation plans can be provided, thereby facilitating the promotion and application of the technical scheme provided in this application; in addition, the grafting rate of a specific type of vinyl resin with the UV conversion agent and the UV absorber is higher and the stability after grafting is also higher.

[0019] In some optional embodiments, the vinyl resin is selected from at least one of a copolymer of ethylene and vinyl acetate, a copolymer of ethylene and 1-butene, and a copolymer of ethylene and 1-octene.

[0020] Optionally, the number average molecular weight of the vinyl resin is 50,000 to 400,000 g / mol.

[0021] In the above technical solution, the type of vinyl resin is further limited so that the grafting rate with the ultraviolet light converting agent and the ultraviolet light absorbing agent is higher and the stability after grafting is also higher.

[0022] In addition, the number average molecular weight of the vinyl resin is further limited within a specific range so that the packaging film has a relatively excellent visible light transmittance.

[0023] In some optional embodiments, the encapsulation film includes an ultraviolet light conversion and light absorption layer, and the raw materials for preparing the ultraviolet light conversion and light absorption layer include 80 to 99.8 parts of vinyl resin, 0.01 to 9.9 parts of ultraviolet light conversion agent and 0.01 to 9.9 parts of ultraviolet light absorber by weight.

[0024] In some optional embodiments, the encapsulation film includes a stacked ultraviolet conversion layer and an ultraviolet light absorbing layer. In terms of weight, the raw materials for preparing the ultraviolet conversion layer include 80 to 99.8 parts of vinyl resin and 0.01 to 9.9 parts of ultraviolet conversion agent, and the raw materials for preparing the ultraviolet light absorbing layer include 80 to 99.8 parts of vinyl resin and 0.01 to 9.9 parts of ultraviolet absorber.

[0025] In the above technical solution, the specific type of the encapsulation film is not limited, for example, it can be a single-layer structure or a multi-layer structure (such as a double-layer), and can be adaptively adjusted according to actual application needs.

[0026] In a second aspect, an embodiment of the present application provides a solar photovoltaic module, comprising the encapsulation film provided in the embodiment of the first aspect.

[0027] In the above technical scheme, the solar photovoltaic module includes the encapsulation film provided by the first aspect embodiment. Since the encapsulation film can convert most of the difficult-to-use and harmful ultraviolet light into usable visible light, the remaining small part of the ultraviolet light can also be absorbed by it and will not act on the photovoltaic module, and the ultraviolet converter and ultraviolet absorber in the encapsulation film can play a role stably for a long time, so that the photovoltaic module using the encapsulation film can have a higher module power for a long time. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0029] It should be noted that “and / or” in this application, such as “Feature 1 and / or Feature 2”, refers to the three situations of “Feature 1” alone, “Feature 2” alone, or “Feature 1” plus “Feature 2”.

[0030] In addition, in the description of the present application, unless otherwise specified, the meaning of "multiple" in "one or more" refers to two or more; the range of "value a ~ value b" includes the two end values ​​"a" and "b", and the "unit" in "value a ~ value b + unit of measurement" represents the "unit of measurement" of both "value a" and "value b".

[0031] The following is a detailed description of a packaging film and a solar photovoltaic module according to an embodiment of the present application.

[0032] In a first aspect, an embodiment of the present application provides a packaging film. The raw materials for preparing the packaging film include a vinyl resin, an ultraviolet light conversion agent, and an ultraviolet light absorber in terms of weight fraction. The structural formula of the ultraviolet light conversion agent is shown in Formula I:

[0033]

[0034] Wherein, R4 and R6 are independently selected from any one of a C1-C20 alkyl group, a C3-C20 alkyl group in which at least one methylene group is substituted by -NHCOO-, and a substituted or unsubstituted C2-C20 alkenyl group; R5 is selected from a C3-C20 hydrocarbon group substituted by at least one of an epoxy group, -OH and -NCO; and the functional groups in the ultraviolet absorber include at least one of a vinyl group, an acrylic group, a methacrylic group, a carboxyl group, an epoxy group, an acyl chloride group and an isocyanate group.

[0035] It should be noted that the ultraviolet light converter refers to a substance that can convert ultraviolet light into visible light, and the ultraviolet light absorber refers to a substance that can absorb ultraviolet light.

[0036] In the present application, the raw materials for preparing the encapsulation film contain both a UV converter with a specific structure and a UV absorber with a specific structure. On the one hand, the encapsulation film contains a UV converter with a specific structure, which can convert UV light into visible light that can be used by solar photovoltaic modules, thereby helping to improve the module power of the photovoltaic modules; and the UV converter with a specific structure can also be stably grafted with the polymer matrix (mainly achieved through the R5 group in the structure), so that the photovoltaic modules can have a high module power for a long time. On the other hand, the encapsulation film also contains a UV absorber with a specific structure, which can absorb the residual UV light that has not been converted (that is, it can effectively protect the photovoltaic modules), thereby effectively solving the problem of poor module power caused by module light decay; and the UV absorber with a specific structure can also be stably grafted with the polymer matrix, so as to be able to protect the photovoltaic modules for a long time and continuously (if the UV absorber cannot be grafted with the polymer matrix, it is easy to migrate during use, resulting in a reduced concentration and uneven distribution, making it difficult to effectively protect the photovoltaic modules for a long time). Through the combined effect of these two aspects, the encapsulation film can convert most of the difficult-to-use and harmful ultraviolet light into usable visible light, and the remaining small amount of ultraviolet light can also be absorbed by it without affecting the photovoltaic modules. In addition, the ultraviolet converter and ultraviolet absorber in the encapsulation film can function stably for a long time, so that the photovoltaic modules using the encapsulation film can have a higher module power for a long time.

[0037] As an example, R4 and R6 are each independently selected from any one of a C1-C10 alkyl group, a C3-C10 alkyl group in which at least one methylene group is substituted by -NHCOO-, and a substituted or unsubstituted C2-C10 alkenyl group; and / or, R5 is selected from a C3-C10 hydrocarbon group substituted by at least one of an epoxy group, -OH and -NCO.

[0038] In this embodiment, R4 to R6 are further limited to a specific range so that the UV converter can more effectively convert UV light into visible light. At the same time, it can also improve its grafting rate with the polymer matrix and the stability after grafting. In addition, it can also reduce the preparation cost of the corresponding packaging film.

[0039] As an example, R5 also contains -NHCOO- and / or -CO-. In this embodiment, -NHCOO- and -CO- have a certain catalytic effect, and the presence of the two helps the ultraviolet light conversion agent and the polymer matrix to be grafted more easily, thereby improving the grafting efficiency and the stability after grafting.

[0040] As an example, the ultraviolet light absorber is selected from at least one of substituted triazine ultraviolet light absorbers, benzophenone ultraviolet light absorbers, salicylate ultraviolet light absorbers, benzotriazole ultraviolet light absorbers and substituted acrylonitrile ultraviolet light absorbers.

[0041] In this embodiment, the applicable types of ultraviolet absorbers are relatively abundant, and more feasible implementation plans can be provided, thereby facilitating the promotion and application of the technical solution provided in this application.

[0042] As an example, the ultraviolet absorber is selected from at least one of 3-benzoyl-4-hydroxybenzoic acid, 3-(3-(2H-benzo[d][1,2,3]triazol-2-yl)-5-(tert-butyl)-4-hydroxyphenyl)propionyl chloride, 4-(4,6-bis(2-hydroxyphenyl)-1,3,5-triazine-2-yl)benzoic acid, 3-(2-benzotriazolyl)-4-hydroxy-5-tert-butylbenzenepropionic acid, 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 2-acrylate-2-(4-benzoyl-3-hydroxyphenoxy)ethyl ester and 2-(2'-hydroxy-3'-allyl-5'-methylphenyl)-2H-benzotriazole.

[0043] In this embodiment, the specific type of ultraviolet absorber has the advantages of good ultraviolet light absorption effect and easy acquisition.

[0044] As an example, the vinyl resin is selected from at least one of polyethylene, copolymers of ethylene and 1-butene, copolymers of ethylene and 1-octene, copolymers of ethylene and propylene, copolymers of ethylene and vinyl acetate, copolymers of ethylene and acrylic acid, copolymers of ethylene and maleic anhydride, and copolymers of ethylene and glycidyl methacrylate.

[0045] In this embodiment, the applicable types of vinyl resins are relatively abundant, and more feasible implementation plans can be provided, thereby facilitating the promotion and application of the technical solutions provided in this application; in addition, the grafting rate of a specific type of vinyl resin with the UV conversion agent and the UV absorber is higher and the stability after grafting is also higher.

[0046] As an example, the vinyl resin is at least one selected from a copolymer of ethylene and vinyl acetate, a copolymer of ethylene and 1-butene, and a copolymer of ethylene and 1-octene.

[0047] In this embodiment, the number average molecular weight of the vinyl resin is further limited to a specific range, so that the packaging film has a relatively excellent visible light transmittance.

[0048] As an example, the number average molecular weight of the vinyl resin is 50,000 to 400,000 g / mol, for example but not limited to any one of 50,000 g / mol, 100,000 g / mol, 200,000 g / mol, 300,000 g / mol and 400,000 g / mol or a range between any two of them.

[0049] In this embodiment, the type of vinyl resin is further limited so that the grafting rate with the ultraviolet light converting agent and the ultraviolet light absorbing agent is higher and the stability after grafting is also higher.

[0050] It is understandable that the raw materials for preparing the encapsulation film contain some necessary auxiliary agents in addition to the vinyl resin, the UV conversion agent and the UV absorber.

[0051] As an example, the raw materials for preparing the encapsulation film further include 0.18 to 15 parts of an auxiliary agent, and the auxiliary agent includes at least one of an initiator, a cross-linking agent, a coupling agent, an antioxidant and a light stabilizer.

[0052] It should be noted that the types of various functional additives are not limited and can be set according to routine selection in the art.

[0053] As an example, the initiator is selected from at least one of tert-butyl peroxy isopropyl carbonate, 2,5-dimethyl-2,5-(bis-tert-butylperoxy)hexane, tert-butyl peroxy-2-ethylhexyl carbonate, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-amyl peroxy 2-ethylhexyl carbonate, azobisisobutyronitrile, azobisisovaleronitrile, azobisisobutyramidine hydrochloride, azobisisobutylimidazoline hydrochloride and azoisobutylcyanoformamide.

[0054] As an example, the crosslinking agent is selected from triallyl isocyanurate, triallyl cyanurate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, tris(2-hydroxyethyl)isocyanuric acid triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, trimethylolpropane tetraacrylate, ditrimethylolpropane At least one of 2,4,6-tris(2-propenyloxy)-1,3,5-triazine, tricyclopentane dimethanol diacrylate, propoxylated neopentyl glycol diacrylate, ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, 2-butyl-2-ethyl-1,3-propanediol diacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate and polyethylene glycol dimethacrylate.

[0055] As an example, the coupling agent is selected from at least one of vinyltriethoxysilane, vinyltrimethoxysilane, vinyltriperoxide tert-butylsilane, vinyltriacetoxysilane, vinyltri(β-methoxyethoxy)silane, γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethylsilane and 3-aminopropyltrimethylsilane.

[0056] As an example, the antioxidant is selected from at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, distearyl thiodipropionate, pentaerythritol tetrakis(3-laurylthiopropionate), didodecyl thiodipropionate, nonyl-N-(nonylphenyl)aniline and 4,6-bis(octylthiomethyl)-o-cresol.

[0057] As an example, the light stabilizer is selected from at least one of bis-2,2,6,6-tetramethylpiperidinol sebacate, 2,4-dichloro-6-(4-morpholinyl)-1,3,5-triazine, bis-1-decyloxy-2,2,6,6-tetramethylpiperidin-4-ol sebacate, a polymer of succinic acid and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol, a polymer of bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate and (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol), a polymer of methyl-1,2,2,6,6-pentamethyl-4-piperidinyl sebacate and (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol), and a polymer of succinic acid and (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol).

[0058] It should be noted that the specific type of the encapsulation film is not limited, for example, it can be a single-layer structure or a multi-layer structure (such as a double-layer), and can be adaptively adjusted according to actual needs.

[0059] As an example, the packaging film includes an ultraviolet light conversion and light absorption layer. The raw materials for preparing the ultraviolet light conversion and light absorption layer include 80 to 99.8 parts of vinyl resin, 0.01 to 9.9 parts of ultraviolet light conversion agent and 0.01 to 9.9 parts of ultraviolet light absorber in terms of weight.

[0060] As an example, the encapsulation film includes a stacked ultraviolet conversion layer and an ultraviolet light absorbing layer. In terms of weight, the raw materials for preparing the ultraviolet conversion layer include 80 to 99.8 parts of vinyl resin and 0.01 to 9.9 parts of ultraviolet conversion agent, and the raw materials for preparing the ultraviolet light absorbing layer include 80 to 99.8 parts of vinyl resin and 0.01 to 9.9 parts of ultraviolet absorber.

[0061] It should be noted that, since the UV converter and UV absorber in the two-layer packaging film are located in different functional layers, the two are relatively independent and can better perform their respective functions, so the embodiments of the present application all take the two-layer packaging film as an example.

[0062] As an example, the thickness ratio of the ultraviolet conversion layer and the ultraviolet absorption layer is (0.8-1.2):1, for example but not limited to the thickness ratio of any point value among 0.8:1, 0.9:1, 1:1, 1.1:1 and 1.2:1 or the range value between any two thereof.

[0063] It should be noted that the preparation process of the double-layer encapsulation film can be carried out according to conventional processes in the art and will not be further introduced in this application.

[0064] It should be noted that the components and their proportions in the packaging film that are not particularly described or limited can be set according to conventional selections in the art.

[0065] In a second aspect, an embodiment of the present application provides a solar photovoltaic module, comprising the encapsulation film provided in the embodiment of the first aspect.

[0066] In the present application, the solar photovoltaic module includes the encapsulation film provided by the first aspect embodiment. Since the encapsulation film can convert most of the difficult-to-use and harmful ultraviolet light into usable visible light, the remaining small part of the ultraviolet light can also be absorbed by it and will not act on the photovoltaic module, and the ultraviolet converter and ultraviolet absorber in the encapsulation film can play a role stably for a long time, so that the photovoltaic module using the encapsulation film can have a higher module power for a long time.

[0067] In order to better understand the technical solution of the present application, a double-layer packaging film is used for auxiliary explanation.

[0068] As an example, a solar photovoltaic module includes a photovoltaic glass panel, a first packaging film, a photovoltaic cell array, a second packaging film, a photovoltaic glass panel or an organic back panel that are stacked in sequence, wherein the first packaging film and / or the second packaging film is a double-layer packaging film provided in the first aspect embodiment, and the ultraviolet conversion layer is located on the side close to the photovoltaic glass panel, and the ultraviolet absorption layer is located on the side close to the cell array.

[0069] It should be noted that there is no limit to the type of cells in the photovoltaic cell array, for example, it can be any one of PERC (Passivated Emitter Rear Cell), TOPCon (Tunnel Oxide Passivated Contact), HJT (Heterojunction with Intrinsic Thin-film) and BC (Back Contact).

[0070] It should be noted that any structural or functional unit not specifically described or limited in the solar photovoltaic assembly may be arranged according to conventional selections in the art.

[0071] The features and performance of the present application are further described in detail below in conjunction with the embodiments.

[0072] Example 1

[0073] The present invention provides a method for preparing a double-layer packaging film, comprising the following steps:

[0074] Preparation of S1 UV conversion agent A:

[0075] Benzotriazole (5.96 g) was heated and dissolved in 30 mL of nitric acid. Liquid bromine (23.95 g) was slowly dripped into the reaction system under stirring conditions, and refluxed and stirred at 110°C for 24 h. The reaction mixture was placed in ice water, and the reaction was quenched with saturated sodium hydroxide solution and saturated sodium bisulfite solution. The solid precipitated, washed with water and filtered to obtain an off-white powdery initial product, which was recrystallized in ethanol to obtain 3.1 g of white solid powder with a yield of 22%.

[0076] 4,7-dibromo-2H-benzo[d][l,2,3]triazole (i.e., the above-mentioned white solid powder 1.37g), 4-tert-butylphenylboric acid (3.13g), potassium carbonate (3.3g), tetrakistriphenylphosphine palladium (0.23g) were mixed in a three-necked flask and replaced with nitrogen. 18mL of degassed toluene and 12mL of deionized water were added to the reaction system. Stir and heat to reflux for 48h. The reaction was quenched in ice water, washed with saturated sodium chloride aqueous solution, extracted with dichloromethane, and the organic phase was dried with anhydrous magnesium sulfate. The solvent was removed under reduced pressure, and the residue was chromatographed (silica gel, petroleum ether / dichloromethane / ethyl acetate) to finally obtain 1.3g of 4,7-bis(4-tert-butylphenyl)-2H-benzo[d][1,2,3]triazole crude product with a yield of about 65%.

[0077] The mixture of the above crude product of 4,7-bis(4-tert-butylphenyl)-2H-benzo[d][1,2,3]triazole (2.8 g), potassium hydroxide (3.8 g) and dimethylformamide (50 mL) was placed in ice water and fully replaced with nitrogen, then epibromopropane (1.2 g) was slowly added, and then the temperature was raised to 40°C and reacted for 24 hours. The reaction mixture was poured into ice water, washed with a saturated sodium chloride solution, and then extracted with dichloromethane. The organic phase obtained by extraction was dried with anhydrous magnesium sulfate, and the volatiles were removed under reduced pressure. The crude product of ultraviolet light conversion agent A was separated and purified by chromatography (silica gel, petroleum ether / dichloromethane / ethyl acetate) to obtain 1.2 g of the yield of about 37%.

[0078] The specific reaction equation is as follows:

[0079]

[0080] Preparation of S2 UV light conversion agent masterbatch and UV light absorber masterbatch

[0081] Preparation of UV conversion agent masterbatch: UV conversion agent A and EVA resin are fully mixed in a mass ratio of 5:95, vacuum dried in an oven at 60 degrees for 24 hours, 0.5wt% of di-tert-butyl peroxide is added, and 5wt% UV conversion agent A masterbatch is prepared by granulation at 90°C using a twin-screw extruder.

[0082] Preparation of UV absorber masterbatch: The UV absorber 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole and EVA resin were fully mixed in a mass ratio of 5:95, vacuum dried in an oven at 60 degrees for 24 hours, 0.5wt% of di-tert-butyl peroxide was added, and granulated at 100°C by a twin-screw extruder to prepare a 5wt% concentration of UV absorber masterbatch.

[0083] S3 Preparation of UV light conversion layer materials and UV light absorption layer materials

[0084] Preparation of raw materials for ultraviolet conversion layer: 4 parts of the above-mentioned ultraviolet conversion agent A masterbatch, 96 parts of Sulbang EVA resin, 0.51 parts of tert-butyl peroxycarbonate-2-ethylhexyl ester, 0.53 parts of triallyl isocyanurate, 0.25 parts of vinyl triisopropoxy silane, 0.32 parts of 3,5-di-tert-butyl-4-hydroxy-benzoic acid hexadecyl ester and 0.43 parts of 4,4'-thiobis(3-methyl-6-tert-butylphenol) were weighed in parts by mass, and placed in a mixing kettle for stirring and mixing to obtain the raw materials for the ultraviolet conversion layer.

[0085] Preparation of raw materials for ultraviolet light absorbing layer: Weigh 9 parts of the above-mentioned ultraviolet light absorbing agent masterbatch, 91 parts of Formosa Plastics EVA resin, 0.62 parts of tert-butyl peroxycarbonate-2-ethylhexyl ester, 0.61 parts of triallyl isocyanurate, 0.25 parts of γ-methacrylate acyloxypropyl trimethoxysilane, 0.32 parts of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and 0.43 parts of bis-2,2,6,6-tetramethylpiperidinol sebacate, place them in a mixing kettle for stirring and mixing, and obtain the raw materials for ultraviolet light absorbing layer.

[0086] S4 Extrusion Casting

[0087] The mixed raw materials of the ultraviolet light conversion layer and the raw materials of the ultraviolet light absorption layer are extruded into a double-layer EVA film in a mass ratio of 1:1 by a screw extruder, and then embossed, pulled and rolled to obtain a rolled packaging film with a film thickness of 0.50 mm, of which the thickness of the ultraviolet light conversion layer is 0.25 mm and the thickness of the ultraviolet light absorption layer is 0.25 mm.

[0088] Example 2

[0089] The present embodiment provides a method for preparing a double-layer packaging film, which differs from the embodiment 1 only in that:

[0090] In step S1, by replacing the raw materials, the ultraviolet light conversion agent prepared is ultraviolet light conversion agent C, and the structure is as follows:

[0091]

[0092] In step S2, the ultraviolet light absorber is 2-(4-benzoyl-3-hydroxyphenoxy)ethyl 2-acrylate.

[0093] Example 3

[0094] The present embodiment provides a method for preparing a double-layer packaging film, which differs from the embodiment 1 only in that:

[0095] In step S1, by replacing the raw materials, the ultraviolet light conversion agent prepared is ultraviolet light conversion agent D, and the structure is as follows:

[0096]

[0097] Comparative Example 1

[0098] The comparative example of the present application provides a method for preparing a double-layer packaging film, which is different from Example 1 only in that in step S2, the ultraviolet light absorber is 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole.

[0099] Comparative Example 2

[0100] The comparative example of the present application provides a method for preparing a double-layer packaging film, which differs from Example 1 only in that:

[0101] In step S1, by replacing the raw materials, the structure of the ultraviolet light conversion agent prepared is as follows:

[0102]

[0103] Comparative Example 3

[0104] The comparative example of the present application provides a method for preparing a double-layer packaging film, which differs from Example 1 only in that:

[0105] In step S1, by replacing the raw materials, the structure of the ultraviolet light conversion agent prepared is as follows:

[0106]

[0107] In step S2, the ultraviolet light absorber is 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole.

[0108] Comparative Example 4

[0109] The comparative example of the present application provides a method for preparing a double-layer packaging film, comprising the following steps:

[0110] S1 UV absorber masterbatch preparation

[0111] Preparation of UV absorber masterbatch: The UV absorber 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole and EVA resin were fully mixed in a mass ratio of 5:95, vacuum dried in an oven at 60 degrees for 24 hours, 0.5wt% of di-tert-butyl peroxide was added, and granulated at 100°C by a twin-screw extruder to prepare a 5wt% concentration of UV absorber masterbatch.

[0112] Preparation of S2 polymer layer raw materials and UV light absorbing layer raw materials

[0113] Preparation of polymer layer raw materials: 100 parts of Sulbang EVA resin, 0.51 parts of tert-butyl peroxycarbonate-2-ethylhexyl ester, 0.53 parts of triallyl isocyanurate, 0.25 parts of vinyl triisopropoxy silane, 0.32 parts of 3,5-di-tert-butyl-4-hydroxy-benzoic acid hexadecyl ester and 0.43 parts of 4,4'-thiobis(3-methyl-6-tert-butylphenol) were weighed in parts by mass, and placed in a mixing kettle for stirring and mixing to obtain the polymer layer raw materials.

[0114] Preparation of raw materials for ultraviolet light absorbing layer: Weigh 9 parts of the above-mentioned ultraviolet light absorbing agent masterbatch, 91 parts of Formosa Plastics EVA resin, 0.62 parts of tert-butyl peroxycarbonate-2-ethylhexyl ester, 0.61 parts of triallyl isocyanurate, 0.25 parts of γ-methacrylate acyloxypropyl trimethoxysilane, 0.32 parts of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and 0.43 parts of bis-2,2,6,6-tetramethylpiperidinol sebacate, place them in a mixing kettle for stirring and mixing, and obtain the raw materials for ultraviolet light absorbing layer.

[0115] S3 Extrusion Casting

[0116] The mixed polymer layer raw material and ultraviolet light absorbing layer raw material are extruded into a double-layer EVA film in a mass ratio of 1:1 by a screw extruder, and then embossed, pulled and rolled to obtain a rolled packaging film with a film thickness of 0.50 mm, of which the polymer layer thickness is 0.25 mm and the ultraviolet light absorbing layer thickness is 0.25 mm.

[0117] It should be noted that the difference between Comparative Example 4 and Comparative Example 1 is that no ultraviolet light conversion agent is used.

[0118] Test example

[0119] Performance test of packaging film

[0120] Test method:

[0121] The encapsulation films prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were numbered respectively, and then the transmittance of each sample was tested; then, each sample was assembled into a photovoltaic module, and the module power and the mobility of the active ingredients of each photovoltaic module were tested, and then the statistics were shown in Table 1.

[0122] Among them, the transmittance test steps are as follows: hot press the cast film at 150°C for 18 minutes to obtain a laminated film sample, and test the light transmittance according to the test method provided in "GB / T29848-2018", in units of %.

[0123] The assembly steps of the photovoltaic module are as follows: stack photovoltaic glass, packaging film sample, battery cell array, high-transmittance film (without UV conversion agent and UV absorber), and photovoltaic glass in this order, and seal the edges with a porous tape, wherein the UV absorption layer of the film is close to the battery cell, and the UV conversion layer is close to the photovoltaic glass, and then laminated with a vacuum laminator at a lamination temperature of 145°C and a lamination time of 18 minutes, and then cool to obtain a solar module.

[0124] The steps for the component power test of photovoltaic modules are as follows: prepare test samples in accordance with GB / T29848-2018 and perform current and voltage tests on photovoltaic modules in units of W.

[0125] The test steps for the mobility of the active ingredients are as follows: a rapid aging migration test is performed at the component end, the front of the photovoltaic component is a film sample, and the back of the component is a high-transmittance film without UV conversion agent and UV absorber. After the component has been aged at 120°C for 48 hours in an aging box, the film on the front of the component is removed and heated and soaked in an organic solvent (such as acetone) (stirring and heating and soaking at 60°C for 24 hours). The solution after soaking is analyzed for the components of UV cutoff agent and UV conversion agent to obtain the content of the corresponding components in the film after aging (A). The film on the front of the component that has not been aged is removed, and the same heating and soaking treatment is performed. The solution after soaking is analyzed to obtain the content of the corresponding components before aging (B). The mobility is: (BA) / B*100%. When the mobility is greater than 3%, it is considered that the migration of the corresponding component has occurred.

[0126] Table 1

[0127]

[0128] Referring to Table 1, it can be seen from the test results of Examples 1 to 3 and Comparative Examples 1 to 4 that the transmittance of ultraviolet light and visible light of the encapsulation film with a specific structure provided by the embodiments of the present application (i.e., the encapsulation film contains both an ultraviolet light converter with a specific structure and an ultraviolet light absorber with a specific structure) is substantially the same as that of the existing encapsulation film, and the corresponding photovoltaic module has a higher module power. Moreover, the ultraviolet light converter with a specific structure and the ultraviolet light absorber with a specific structure in the encapsulation film can both stably exist in the encapsulation film for a long time and play their respective roles, so that the module can have a higher module power for a long time.

[0129] It can be seen from the test results of Examples 1 to 3 and Comparative Examples 1 to 3 that only the UV conversion agents and UV absorbers with specific structures provided in the embodiments of the present application can achieve long-term and stable grafting with the polymer matrix while exerting their respective functions, while UV conversion agents and UV absorbers with conventional structures do not have the effect of stable grafting and cannot enable photovoltaic modules to have a higher module power for a long time.

[0130] It can be seen from the test results of Example 1 and Comparative Example 4 that the encapsulation film contains the UV conversion agent of the specific structure provided by the present application, and the photovoltaic module corresponding to the encapsulation film has a higher module power than the one without the UV conversion agent.

[0131] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

Claims

1. A packaging film, characterized in that: The raw materials for preparing the encapsulation film include vinyl resin, ultraviolet light conversion agent and ultraviolet light absorber in terms of weight percentage; The structural formula of the ultraviolet light conversion agent is shown in Formula I: wherein R4 and R6 are each independently selected from any one of a C1-C20 alkyl group, a C3-C20 alkyl group in which at least one methylene group is substituted with -NHCOO-, and a substituted or unsubstituted C2-C20 alkenyl group, and R5 is selected from a C3-C20 hydrocarbon group substituted with at least one of an epoxy group, -OH and -NCO; The functional group in the ultraviolet light absorber includes at least one of vinyl, acrylic, methacrylic, carboxyl, epoxy, acyl chloride and isocyanate.

2. The packaging film according to claim 1, characterized in that: R4 and R6 are each independently selected from any one of a C1-C10 alkyl group, a C3-C10 alkyl group in which at least one methylene group is substituted with -NHCOO-, and a substituted or unsubstituted C2-C10 alkenyl group; And / or, R5 is selected from a C3-C10 hydrocarbon group substituted by at least one of an epoxy group, -OH and -NCO.

3. The packaging film according to claim 2, characterized in that: R5 further contains -NHCOO- and / or -CO-.

4. The packaging film according to claim 1, characterized in that: The ultraviolet light absorber is selected from at least one of substituted triazine ultraviolet light absorbers, benzophenone ultraviolet light absorbers, salicylate ultraviolet light absorbers, benzotriazole ultraviolet light absorbers and substituted acrylonitrile ultraviolet light absorbers.

5. The packaging film according to claim 4, characterized in that: The ultraviolet light absorber is selected from at least one of 3-benzoyl-4-hydroxybenzoic acid, 3-(3-(2H-benzo[d][1,2,3]triazol-2-yl)-5-(tert-butyl)-4-hydroxyphenyl)propionyl chloride, 4-(4,6-bis(2-hydroxyphenyl)-1,3,5-triazine-2-yl)benzoic acid, 3-(2-benzotriazolyl)-4-hydroxy-5-tert-butylbenzenepropionic acid, 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 2-acrylic acid-2-(4-benzoyl-3-hydroxyphenoxy)ethyl ester and 2-(2'-hydroxy-3'-allyl-5'-methylphenyl)-2H-benzotriazole.

6. The packaging film according to claim 1, characterized in that: The vinyl resin is selected from at least one of polyethylene, copolymers of ethylene and 1-butene, copolymers of ethylene and 1-octene, copolymers of ethylene and propylene, copolymers of ethylene and vinyl acetate, copolymers of ethylene and acrylic acid, copolymers of ethylene and maleic anhydride, and copolymers of ethylene and glycidyl methacrylate.

7. The packaging film according to claim 6, characterized in that: The vinyl resin is selected from at least one of a copolymer of ethylene and vinyl acetate, a copolymer of ethylene and 1-butene, and a copolymer of ethylene and 1-octene; Optionally, the number average molecular weight of the vinyl resin is 50,000 to 400,000 g / mol.

8. The encapsulation film according to any one of claims 1 to 7, characterized in that: The packaging film includes an ultraviolet light conversion and light absorption layer. The raw materials for preparing the ultraviolet light conversion and light absorption layer include 80 to 99.8 parts of the vinyl resin, 0.01 to 9.9 parts of the ultraviolet light conversion agent and 0.01 to 9.9 parts of the ultraviolet light absorber in terms of weight.

9. The encapsulation film according to any one of claims 1 to 7, characterized in that: The encapsulation film includes a stacked ultraviolet conversion layer and an ultraviolet light absorbing layer. In terms of weight percentage, the raw materials for preparing the ultraviolet conversion layer include 80 to 99.8 parts of the vinyl resin and 0.01 to 9.9 parts of the ultraviolet conversion agent, and the raw materials for preparing the ultraviolet light absorbing layer include 80 to 99.8 parts of the vinyl resin and 0.01 to 9.9 parts of the ultraviolet light absorber.

10. A solar photovoltaic module, characterized in that: The invention comprises the encapsulation film as claimed in any one of claims 1 to 9.

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