White EVA packaging adhesive film and preparation method and application thereof

Abstract

The invention provides a white EVA (Ethylene Vinyl Acetate) packaging adhesive film as well as a preparation method and application thereof. The white EVA packaging adhesive film is prepared from the following raw materials in parts by mass: 90 to 98 parts of ethylene-vinyl acetate copolymer resin, 2 to 10 parts of modified titanium dioxide, 0.5 to 1.5 parts of a cross-linking agent, 0.5 to 1.5 parts of an assistant cross-linking agent and 0.5 to 1 part of a silane coupling agent, a modifier of the modified titanium dioxide is long-chain alkyl bipod silane. According to the white EVA packaging adhesive film, the components of the white EVA packaging adhesive film are designed, and the white EVA packaging adhesive film which is good in adhesion, high in damp-heat aging resistance and good in water resistance is prepared.

Description

Technical Field

[0001] The invention belongs to the technical field of solar cells, and in particular relates to a white EVA packaging film and a preparation method and application thereof. Background Art

[0002] For single-glass solar cell modules, a white encapsulation film with high reflectivity is generally used on the back of the cell to reflect the sunlight that passes through the cell back to the cell, reducing the loss of sunlight, greatly increasing the utilization rate of sunlight, and thus improving the photoelectric conversion efficiency. The principle of white encapsulation film is mainly to add pigments such as titanium dioxide to the EVA film to improve its reflective performance. In order to solve the appearance problems such as wrinkles and white overflow of the white film, electron beam irradiation pretreatment technology is generally used.

[0003] CN116535996A discloses a water vapor barrier anti-aging white EVA encapsulation film and its preparation process, especially a white EVA encapsulation film for single glass component encapsulation, belonging to the photovoltaic field. The encapsulation film includes the following components by mass fraction: 40-89.5 parts of EVA resin raw material, 5-20 parts of high body impedance aging masterbatch, 0.1-2.0 parts of high performance water barrier, 5-30 parts of composite white masterbatch, 0.2-2.0 parts of cross-linking agent, 0.1-2.0 parts of auxiliary cross-linking agent, 0.05-2.0 parts of silane coupling agent, and 0.05-2.0 parts of light stabilizer. The prepared film has the characteristics of improved anti-PID ability, high water vapor barrier, low free acetic acid formation, high film melting point, etc. Cooperate with the optimization of electron beam irradiation process to improve the whitening of the film and improve the adhesion formed after irradiation and during high temperature transportation.

[0004] However, existing white EVA encapsulation films have the following problems: (1) white fillers such as titanium dioxide have dispersion problems in the resin, resulting in uneven overall performance of the film. After long-term use, insufficient adhesion leads to delamination; (2) electron beam irradiation will lock some silane, resulting in reduced adhesion and resistance to moisture and heat aging of the film; (3) the backplane in the single-glass module has low water barrier properties, and the water barrier properties of the film need to be improved to protect the battery cells.

[0005] Therefore, how to provide a white EVA encapsulation film with high adhesion, resistance to moisture and heat aging, and good water barrier properties has become a technical problem that urgently needs to be solved in this field. Summary of the invention

[0006] In view of the shortcomings of the prior art, the object of the present invention is to provide a white EVA encapsulation film and a preparation method and application thereof. The present invention designs the components of the white EVA encapsulation film and further uses a specific modified titanium dioxide to prepare a white EVA encapsulation film with good adhesion, high resistance to wet and hot aging and good water barrier properties.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a white EVA encapsulation film, wherein the raw materials for preparing the white EVA encapsulation film include the following components in parts by weight:

[0009]

[0010] The modifier of the modified titanium dioxide comprises long-chain alkyl bipodal silane.

[0011] The present invention designs the components of the white EVA encapsulation film and further uses specific modified titanium dioxide to prepare a white EVA encapsulation film with good adhesion, high resistance to moisture and heat aging and good water barrier properties.

[0012] Conventional silane has only 3 siloxane groups, while long-chain alkyl bipedal silane has more than 5 siloxane groups. In the present invention, titanium dioxide is modified by using a specific modifier to obtain a specific modified titanium dioxide. Further, the surface of titanium dioxide is modified by using a long-chain alkyl bipedal silane coupling agent to improve the compatibility and dispersibility of titanium dioxide in the resin substrate, and the long-chain alkyl bipedal silane has a flexible long chain, which can reduce the surface energy and improve the hydrophobicity. By using a long-chain alkyl bipedal silane with more than 5 siloxane groups, the density of siloxanes at the interface is increased, the adhesion of the white EVA encapsulation film is improved, and the high resistance to wet heat aging of the white EVA encapsulation film is improved.

[0013] In the present invention, in the white EVA packaging film, the weight proportion of the ethylene-vinyl acetate copolymer resin (EVA resin) can be 90 parts, 91 parts, 92 parts, 93 parts, 94 parts, 95 parts, 96 parts, 97 parts or 98 parts.

[0014] The weight proportions of the modified titanium dioxide can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts, etc.

[0015] The weight proportion of the auxiliary cross-linking agent can be 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1.0 parts, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts or 1.5 parts, etc.

[0016] The weight proportion of the silane coupling agent may be 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts or 1 parts.

[0017] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0018] As a preferred technical solution of the present invention, the number of carbon atoms in the longest carbon chain alkyl group in the long-chain alkyl bipodal silane is ≥ 6 (for example, it can be 6, 7, 8, 9, 10, 11, 12, 13 or 14, etc.), preferably 6-12.

[0019] Preferably, the number of alkoxy groups in the long-chain alkyl bipodal silane is ≥5 (eg, 5, 6, or 7, etc.), and more preferably, 5 or 6.

[0020] In the present invention, by selecting a long-chain alkyl bipod silane with a relatively long carbon chain alkyl group, the surface energy of the white EVA encapsulation film can be reduced and the hydrophobicity of the white EVA encapsulation film can be improved; by selecting a long-chain alkyl bipod silane with a relatively large number of alkoxy groups, the density of siloxanes at the interface can be increased, the adhesion of the white EVA encapsulation film can be increased, and the high resistance to wet heat aging of the white EVA encapsulation film can be improved.

[0021] Preferably, the long-chain alkyl bipodal silane is selected from any one or a combination of at least two of 1,2-bis(triethoxysilyl)decane, 1,1,1,3,3-pentamethoxy-1,3-disilatridecane, 1,10-bis(trimethoxysilyl)octane, 1,8-bis(triethoxysilyl)octane or 1,6-bistrimethoxysilylhexane.

[0022] Preferably, based on the mass percentage of titanium dioxide in the modified titanium dioxide being 100%, the mass percentage of the modifier is 3-8%, for example, it can be 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5% or 8%, etc.

[0023] In the present invention, by controlling the amount of the modifier within a specific range, the titanium dioxide can be modified to a better extent, thereby preparing a white EVA packaging film with excellent performance. If the amount of the modifier is too little, the modification effect on the titanium dioxide is poor, resulting in poor compatibility and dispersibility of the modified titanium dioxide with the resin substrate, thereby resulting in poor comprehensive performance of the white EVA packaging film; if the amount of the modifier is too much, it will cause a waste of raw materials, thereby increasing the production cost of the white EVA packaging film.

[0024] Preferably, the titanium dioxide in the modified titanium dioxide is selected from rutile titanium dioxide, including but not limited to rutile titanium dioxide with the grades of Longbai 886, Panhua DR-2588 or CITIC CR-210.

[0025] It should be noted that there is no special restriction on the particle size of titanium dioxide in the present invention, and titanium dioxide within the commonly used particle size range in the art is applicable.

[0026] It should be noted that there is no special limitation on the preparation method of modified titanium dioxide in the present invention, and all commonly used preparation methods in the art are applicable, including but not limited to:

[0027] An alcohol solvent and water are mixed in a volume ratio of 1:(0.8-1.2) to obtain 50 mL of a mixed solvent, and aqueous ammonia is added thereto to adjust the pH to 8.5-9.5;

[0028] Weigh 10g of dry titanium dioxide and add it to the above reaction system for ultrasonic dispersion for 8-15min, then heat to 75-85°C and stir for 15-25min to evenly disperse the titanium dioxide in the mixed solvent;

[0029] An ethanol solution containing long-chain alkyl bipodal silane (ethanol dosage is 10 mL) is added dropwise to the above reaction system, reacted at 75-85° C. for 1-2 hours, aged at room temperature, filtered, washed and dried to obtain the modified titanium dioxide.

[0030] The alcohol solvent includes anhydrous ethanol;

[0031] Taking the mass percentage of titanium dioxide in the modified titanium dioxide as 100%, the mass percentage of the long-chain alkyl bipodal silane is 3-8%.

[0032] As a preferred technical solution of the present invention, the mass percentage of the vinyl acetate structure in the ethylene-vinyl acetate copolymer resin is 26-33%, for example, it can be 26%, 27%, 28%, 29%, 30%, 31%, 32% or 33%.

[0033] Preferably, the melt index of the ethylene-vinyl acetate copolymer is 6 to 25 g / 10 min, for example, it can be 6 g / 10 min, 8 g / 10 min, 10 g / 10 min, 12 g / 10 min, 15 g / 10 min, 18 g / 10 min, 20 g / 10 min, 22 g / 10 min or 25 g / 10 min.

[0034] Preferably, the ethylene-vinyl acetate copolymer is selected from an ethylene-vinyl acetate copolymer with a mass percentage of vinyl acetate structure of 28% and a melt index of 6 g / 10 min and / or an ethylene-vinyl acetate copolymer with a mass percentage of vinyl acetate structure of 28% and a melt index of 25 g / 10 min.

[0035] Preferably, the ethylene-vinyl acetate copolymer is selected from an ethylene-vinyl acetate copolymer having a mass percentage of vinyl acetate structure of 28% and a melt index of 6 g / 10 min and an ethylene-vinyl acetate copolymer having a mass percentage of vinyl acetate structure of 28% and a melt index of 25 g / 10 min. The mass ratio of the ethylene-vinyl acetate copolymer having a mass percentage of vinyl acetate structure of 28% and a melt index of 6 g / 10 min and the ethylene-vinyl acetate copolymer having a mass percentage of vinyl acetate structure of 28% and a melt index of 25 g / 10 min is 7:3 to 3:7, for example, it can be 7:3, 6:4, 5:5, 4:6 or 3:7, etc.

[0036] Preferably, the ethylene-vinyl acetate copolymer having a vinyl acetate structure mass percentage of 28% and a melt index of 6 g / 10 min includes any one of Formosa Plastics 7670S and Sulbang UE2806, or a combination of at least two of them.

[0037] Preferably, the ethylene-vinyl acetate copolymer having a vinyl acetate structure mass percentage of 28% and a melt index of 25 g / 10 min includes any one of Hanwha E282PV, LG EP28025, Sulbang UE2825, Formosa Plastics 7760S, and V2825, or a combination of at least two thereof.

[0038] As a preferred technical solution of the present invention, the auxiliary cross-linking agent is selected from any one of triallyl isocyanurate, trimethylolpropane triacrylate, tripropylene glycol diacrylate, dipropylene glycol diacrylate, ethoxylated trimethylolpropane trimethacrylate or propoxylated trimethylolpropane trimethacrylate, or a combination of at least two thereof.

[0039] As a preferred technical solution of the present invention, the silane coupling agent is selected from any one of vinyl triethoxysilane, vinyl trimethoxysilane, acryl triperoxide tert-butyl silane, vinyl triacetoxy silane, γ-aminopropyl triethoxy silane, γ-methacryloxypropyl trimethoxy silane or γ-(2,3-epoxypropoxy)propyl trimethoxy silane or a combination of at least two thereof.

[0040] As a preferred technical solution of the present invention, the crosslinking agent is selected from any one of tert-butyl peroxy isopropyl carbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane or 1-bis(tert-butylperoxide)-3,3,5-trimethylcyclohexane or a combination of at least two thereof.

[0041] As a preferred technical solution of the present invention, the raw materials for preparing the white EVA encapsulating film also include 0.1 to 0.5 parts of antioxidants, for example, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts or 0.5 parts.

[0042] Preferably, the antioxidant is selected from any one of 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butyl-4-ethylphenol, β-(4-hydroxy-3,5-di-tert-butylphenyl)acrylate, 6,6'-di-tert-butyl-2,2'-thiodi-p-cresol or 2,2'-methylenebis(6-tert-butyl-4-ethylphenol) or a combination of at least two thereof.

[0043] As a preferred technical solution of the present invention, the raw materials for preparing the white EVA encapsulation film also include 0.1 to 0.5 parts of light stabilizer, for example, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts or 0.5 parts.

[0044] Preferably, the light stabilizer is selected from any one of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate or poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinylethanol) succinate or a combination of at least two thereof.

[0045] In a second aspect, the present invention provides a method for preparing the white EVA encapsulation film as described in the first aspect, the preparation method comprising the following steps:

[0046] The components are mixed, extruded and cast to obtain the white EVA packaging film.

[0047] Preferably, the temperature of the extrusion casting is 70-90°C, for example, it can be 70°C, 72°C, 75°C, 77°C, 80°C, 81°C, 84°C, 88°C or 90°C.

[0048] It should be noted that the present invention does not have any special restrictions on the thickness of the white EVA encapsulation film, which can be designed according to specific needs, and illustratively includes but is not limited to: the thickness of the white EVA encapsulation film is 0.4-0.8 mm, for example, it can be 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm or 0.8 mm, etc.

[0049] In a third aspect, the present invention provides a use of the white EVA encapsulation film as described in the first aspect, wherein the white EVA encapsulation film is used for preparing solar cells.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] In the present invention, the composition of the white EVA encapsulation film is designed, and the titanium dioxide is further modified by using a long-chain alkyl bipodal silane as a modifier to obtain a modified titanium dioxide with a specific structure. Then, by using the specific titanium dioxide and controlling its dosage within a specific range, a white EVA encapsulation film with good adhesion, high resistance to wet and hot aging and good water barrier is prepared, and its water vapor transmission rate is ≤16.9g / (m 2 ·day), specifically 13.6~16.9g / (m 2 ·day), the initial peel strength with the back sheet is ≥118.4N / cm, specifically 118.4~129.8N / cm, the DH2000 H peel strength with the back sheet is ≥60.9N / cm, specifically 60.9~67.5N / cm, Δb(DH 2000h) is ≤1.9, specifically 1.4~1.9, Δb(UV 200kwh / m 2 ) is ≤1.5, specifically 0.8~1.5. DETAILED DESCRIPTION

[0052] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0053] Preparation Example 1

[0054] This preparation example provides a modified titanium dioxide and a preparation method thereof. The preparation method of the modified titanium dioxide is as follows:

[0055] Anhydrous ethanol and water were mixed in a volume ratio of 1:1 to obtain 50 mL of a mixed solvent, to which ammonia water was added to adjust the pH to 9;

[0056] Weigh 10g of dry titanium dioxide (Longbai 886 titanium dioxide) and add it to the above reaction system for ultrasonic dispersion for 10min, then heat to 80°C and stir for 20min to make the titanium dioxide evenly dispersed in the mixed solvent;

[0057] An ethanol solution containing 1,2-bis(triethoxysilyl)decane (ethanol dosage is 10 mL) is added dropwise to the above reaction system, reacted at 80° C. for 1.5 hours, aged at room temperature, filtered, washed and dried to obtain the modified titanium dioxide.

[0058] Taking the mass percentage of titanium dioxide in the modified titanium dioxide as 100%, the mass percentage of 1,2-bis(triethoxysilyl)decane is 5%.

[0059] Preparation Example 2

[0060] This preparation example provides a modified titanium dioxide and a preparation method thereof, which differs from Preparation Example 1 only in that:

[0061] Replace 10g of Longbai 886 titanium dioxide with 10g of Panhua DR-2588 titanium dioxide;

[0062] 1,2-bis(triethoxysilyl)decane was replaced by 1,1,1,3,3-pentamethoxy-1,3-disilatridecane, and the amount thereof remained unchanged;

[0063] The other conditions were the same as those in Preparation Example 1.

[0064] Preparation Example 3

[0065] This preparation example provides a modified titanium dioxide and a preparation method thereof, which differs from Preparation Example 1 only in that:

[0066] Replace 1,2-bis(triethoxysilyl)decane with 1,10-bis(trimethoxysilyl)octane;

[0067] Based on the mass percentage of titanium dioxide in the modified titanium dioxide being 100%, the mass percentage of 1,10-bis(trimethoxysilyl)octane is 6%;

[0068] The other conditions were the same as those in Preparation Example 1.

[0069] Preparation Example 4

[0070] This preparation example provides a modified titanium dioxide and a preparation method thereof, which differs from Preparation Example 1 only in that:

[0071] Replace 1,2-bis(triethoxysilyl)decane with 1,8-bis(triethoxysilyl)octane;

[0072] Taking the mass percentage of titanium dioxide in the modified titanium dioxide as 100%, the mass percentage of 1,8-bis(triethoxysilyl)octane is 8%;

[0073] The other conditions were the same as those in Preparation Example 1.

[0074] Preparation Example 5

[0075] This preparation example provides a modified titanium dioxide and a preparation method thereof, which differs from Preparation Example 1 only in that:

[0076] 1,2-bis(triethoxysilyl)decane was replaced by 1,6-bistrimethoxysilylhexane;

[0077] Taking the mass percentage of titanium dioxide in the modified titanium dioxide as 100%, the mass percentage of 1,6-bistrimethoxysilylhexane is 3%;

[0078] The other conditions were the same as those in Preparation Example 1.

[0079] Comparative Preparation Example 1

[0080] This comparative preparation example provides a modified titanium dioxide and a preparation method thereof, which differs from Preparation Example 3 only in that:

[0081] Replace 1,10-bis(trimethoxysilyl)octane with 1,2-bis(triethoxysilyl)ethane;

[0082] The other conditions were the same as those in Preparation Example 3.

[0083] Comparative Preparation Example 2

[0084] This comparative preparation example provides a modified titanium dioxide and a preparation method thereof, which differs from Preparation Example 3 only in that:

[0085] Replace 1,10-bis(trimethoxysilyl)octane with octyltrimethoxysilane;

[0086] The other conditions were the same as those in Preparation Example 3.

[0087] Comparative Preparation Example 3

[0088] This comparative preparation example provides a titanium dioxide, which is Longbai 886 titanium dioxide.

[0089] Comparative Preparation Example 4

[0090] This comparative preparation example provides a titanium dioxide, which is Panhua DR-2588 titanium dioxide.

[0091] Example 1

[0092] This embodiment provides a white EVA encapsulation film and a preparation method thereof. The raw materials for preparing the white EVA encapsulation film include the following components in parts by mass:

[0093] 90 parts of ethylene-vinyl acetate copolymer resin (Hanhua E282PV), 10 parts of modified titanium dioxide provided in Preparation Example 1, 0.5 parts of triallyl isocyanurate, 0.5 parts of vinyl triethoxysilane, 0.5 parts of tert-butyl peroxy isopropyl carbonate, 0.1 parts of 2,6-di-tert-butyl-p-cresol, and 0.1 parts of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate;

[0094] The preparation method of the above white EVA encapsulation film is as follows:

[0095] The components were mixed and extruded and cast at 80° C. to obtain a white EVA packaging film with a thickness of 0.5 mm.

[0096] Example 2

[0097] This embodiment provides a white EVA encapsulation film and a preparation method thereof. The raw materials for preparing the white EVA encapsulation film include the following components in parts by mass:

[0098] 98 parts of ethylene-vinyl acetate copolymer resin (LG EP28025), 2 parts of modified titanium dioxide provided in Preparation Example 2, 1.5 parts of trimethylolpropane triacrylate, 1 part of vinyltrimethoxysilane, 1.5 parts of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 0.5 parts of 2,6-di-tert-butyl-4-ethylphenol, and 0.5 parts of bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate;

[0099] The preparation method of the white EVA packaging film is the same as that in Example 1.

[0100] Example 3

[0101] This embodiment provides a white EVA encapsulation film and a preparation method thereof. The raw materials for preparing the white EVA encapsulation film include the following components in parts by mass:

[0102] 95 parts of ethylene-vinyl acetate copolymer resin (Formosa Plastics 7760S), 6 parts of modified titanium dioxide provided in Preparation Example 3, 1 part of dipropylene glycol diacrylate, 0.8 parts of γ-aminopropyltriethoxysilane, 1 part of 1-bis(tert-butyl peroxide)-3,3,5-trimethylcyclohexane, 0.4 parts of 6,6'-di-tert-butyl-2,2'-thiodi-p-cresol, and 0.3 parts of bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate;

[0103] The preparation method of the white EVA packaging film is the same as that in Example 1.

[0104] Example 4

[0105] This embodiment provides a white EVA encapsulation film and a preparation method thereof, which differs from Embodiment 3 only in that:

[0106] Replace 6 parts of the modified titanium dioxide provided in Preparation Example 3 with 6 parts of the modified titanium dioxide provided in Preparation Example 4;

[0107] Other conditions are the same as those in Example 3.

[0108] Example 5

[0109] This embodiment provides a white EVA encapsulation film and a preparation method thereof, which differs from Embodiment 3 only in that:

[0110] Replace 6 parts of the modified titanium dioxide provided in Preparation Example 3 with 6 parts of the modified titanium dioxide provided in Preparation Example 5;

[0111] Other conditions are the same as those in Example 3.

[0112] Comparative Example 1

[0113] This comparative example provides a white EVA encapsulation film and a preparation method thereof, which differs from Example 3 only in that:

[0114] Replace 6 parts of the modified titanium dioxide provided in Preparation Example 3 with 6 parts of the modified titanium dioxide provided in Comparative Preparation Example 1;

[0115] Other conditions are the same as those in Example 3.

[0116] Comparative Example 2

[0117] This comparative example provides a white EVA encapsulation film and a preparation method thereof, which differs from Example 3 only in that:

[0118] Replace 6 parts of the modified titanium dioxide provided in Preparation Example 3 with 6 parts of the modified titanium dioxide provided in Comparative Preparation Example 2;

[0119] Other conditions are the same as those in Example 3.

[0120] Comparative Example 3

[0121] This comparative example provides a white EVA encapsulation film and a preparation method thereof, which differs from Example 1 only in that:

[0122] The modified titanium dioxide provided in Preparation Example 1 was replaced by 9.5 parts of titanium dioxide provided in Comparative Preparation Example 3 and 0.5 parts of 1,2-bis(triethoxysilyl)decane;

[0123] Other conditions are the same as in Example 1.

[0124] Comparative Example 4

[0125] This comparative example provides a white EVA encapsulation film and a preparation method thereof, which differs from Example 1 only in that:

[0126] The modified titanium dioxide powder provided in Preparation Example 1 was replaced by 9.5 parts of the titanium dioxide powder provided in Comparative Preparation Example 4 and 0.5 parts of 1,1,1,3,3-pentamethoxy-1,3-disilatridecane;

[0127] Other conditions are the same as in Example 1.

[0128] Comparative Example 5

[0129] This comparative example provides a white EVA encapsulation film and a preparation method thereof, which differs from Example 1 only in that:

[0130] Replace 6 parts of the modified titanium dioxide provided in Preparation Example 1 with 6 parts of the titanium dioxide provided in Comparative Preparation Example 3;

[0131] Other conditions are the same as in Example 1.

[0132] Comparative Example 6

[0133] This comparative example provides a white EVA encapsulation film and a preparation method thereof, which differs from Example 1 only in that:

[0134] Replace 6 parts of the modified titanium dioxide provided in Preparation Example 1 with 6 parts of the titanium dioxide provided in Comparative Preparation Example 4;

[0135] Other conditions are the same as in Example 1.

[0136] The performance of the white EVA packaging film provided in the above embodiment and comparative example was tested, and the specific testing method is as follows:

[0137] The water vapor permeability of the white EVA encapsulation film provided in the above embodiment and comparative example was tested in accordance with GB / T 1037-2021 "Determination of water vapor permeability of plastic films and sheets by cup weight gain and weight loss method";

[0138] According to GB / T 29848-2018 "Ethylene-vinyl acetate copolymer (EVA) adhesive film for photovoltaic module encapsulation", the peel strength-initial, peel strength-DH2000 h, Δb (DH2000h), Δb (UV 200kwh / m 2 ) for testing.

[0139] The specific test data are shown in Table 1 below:

[0140] Table 1

[0141]

[0142]

[0143] As can be seen from the above content, in the present invention, by designing the composition of the white EVA encapsulation film, further modifying the titanium dioxide with a long-chain alkyl bipodal silane as a modifier, a modified titanium dioxide with a specific structure is obtained, and then by using the specific titanium dioxide and controlling its dosage within a specific range, a white EVA encapsulation film with good adhesion, high resistance to wet and hot aging and good water barrier is prepared, and its water vapor transmission rate is ≤16.9g / (m 2 ·day), specifically 13.6~16.9g / (m 2·day), the initial peel strength with the back sheet is ≥118.4N / cm, specifically 118.4~129.8N / cm, the DH2000 H peel strength with the back sheet is ≥60.9N / cm, specifically 60.9~67.5N / cm, Δb(DH 2000h) is ≤1.9, specifically 1.4~1.9, Δb(UV 200kwh / m 2 ) is ≤1.5, specifically 0.8~1.5.

[0144] It can be seen from the contents of Examples 1-5 and Comparative Examples 1-2 that the present invention obtains modified titanium dioxide with a specific structure by selecting a modifier with a specific structure to modify titanium dioxide, thereby further improving the adhesion, moisture and heat aging resistance and water barrier properties of the white EVA encapsulation film.

[0145] It can be seen from the contents of Examples 1-5 and Comparative Examples 3-6 that the present invention obtains modified titanium dioxide with a specific structure by selecting a modifier with a specific structure to modify titanium dioxide, and then prepares a white EVA encapsulation film with good adhesion, high resistance to moisture and heat aging and good water barrier properties.

[0146] In the present invention, the composition of the white EVA encapsulation film is designed, and titanium dioxide is further modified by using a long-chain alkyl bipodal silane as a modifier to obtain a modified titanium dioxide with a specific structure. Furthermore, by using the specific titanium dioxide and controlling its dosage within a specific range, a white EVA encapsulation film with good adhesion, high resistance to moisture and heat aging and good water barrier properties is prepared.

[0147] The applicant declares that the present invention illustrates the detailed process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A white EVA encapsulation film, characterized in that: The raw materials for preparing the white EVA encapsulation film include the following components in parts by mass: The modifier of the modified titanium dioxide comprises long-chain alkyl bipodal silane.

2. The white EVA packaging film according to claim 1, characterized in that: The number of carbon atoms in the longest carbon chain alkyl group of the long-chain alkyl bipodal silane is ≥ 6, preferably 6 to 12; Preferably, the number of alkoxy groups in the long-chain alkyl bipodal silane is ≥ 5, more preferably 5 or 6; Preferably, the long-chain alkyl bipodal silane is selected from any one or a combination of at least two of 1,2-bis(triethoxysilyl)decane, 1,1,1,3,3-pentamethoxy-1,3-disilatridecane, 1,10-bis(trimethoxysilyl)octane, 1,8-bis(triethoxysilyl)octane or 1,6-bistrimethoxysilylhexane; Preferably, based on the mass percentage of titanium dioxide in the modified titanium dioxide being 100%, the mass percentage of the modifier is 3 to 8%; Preferably, the titanium dioxide in the modified titanium dioxide is selected from rutile titanium dioxide.

3. The white EVA encapsulation film according to claim 1 or 2, characterized in that: The mass percentage of the vinyl acetate structure in the ethylene-vinyl acetate copolymer resin is 26-33%; Preferably, the melt index of the ethylene-vinyl acetate copolymer is 6 to 25 g / 10 min; Preferably, the ethylene-vinyl acetate copolymer is selected from an ethylene-vinyl acetate copolymer with a mass percentage of vinyl acetate structure of 28% and a melt index of 6 g / 10 min and / or an ethylene-vinyl acetate copolymer with a mass percentage of vinyl acetate structure of 28% and a melt index of 25 g / 10 min.

4. The white EVA packaging film according to any one of claims 1 to 3, characterized in that: The auxiliary crosslinking agent is selected from any one of triallyl isocyanurate, trimethylolpropane triacrylate, tripropylene glycol diacrylate, dipropylene glycol diacrylate, ethoxylated trimethylolpropane trimethacrylate or propoxylated trimethylolpropane trimethacrylate, or a combination of at least two thereof.

5. The white EVA packaging film according to any one of claims 1 to 4, characterized in that: The silane coupling agent is selected from any one of vinyl triethoxysilane, vinyl trimethoxysilane, acryl triperoxide tert-butyl silane, vinyl triacetoxysilane, γ-aminopropyl triethoxysilane, γ-methacryloxypropyl trimethoxysilane or γ-(2,3-epoxypropyloxy)propyl trimethoxysilane or a combination of at least two thereof.

6. The white EVA packaging film according to any one of claims 1 to 5, characterized in that: The crosslinking agent is selected from any one of tert-butyl peroxyisopropyl carbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane or 1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane or a combination of at least two thereof.

7. The white EVA packaging film according to any one of claims 1 to 6, characterized in that: The raw materials for preparing the white EVA encapsulation film also include 0.1 to 0.5 parts of antioxidant; Preferably, the antioxidant is selected from any one of 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butyl-4-ethylphenol, β-(4-hydroxy-3,5-di-tert-butylphenyl)acrylate, 6,6'-di-tert-butyl-2,2'-thiodi-p-cresol or 2,2'-methylenebis(6-tert-butyl-4-ethylphenol) or a combination of at least two thereof.

8. The white EVA packaging film according to any one of claims 1 to 7, characterized in that: The raw materials for preparing the white EVA encapsulation film also include 0.1 to 0.5 parts of light stabilizer; Preferably, the light stabilizer is selected from any one of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate or poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinylethanol) succinate or a combination of at least two thereof.

9. A method for preparing a white EVA encapsulation film according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: The components are mixed, extruded and cast to obtain the white EVA packaging film.

10. An application of the white EVA packaging film according to any one of claims 1 to 8, characterized in that: The white EVA packaging film is used for preparing solar cells.

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