A kind of synergistic double-layer co-extruded packaging film and its preparation method and application

Abstract

The invention provides a synergistic double-layer co-extruded packaging film and a preparation method and application thereof. The packaging film comprises a modified styrene elastomer layer and a modified EVA layer; the raw materials for preparing the modified styrene elastomer layer comprise a styrene thermoplastic elastomer, a first initiator, a modifier and a first light stabilizer; the raw materials for preparing the modified EVA layer comprise an EVA resin, a second initiator, a cross-linking auxiliary agent and a second light stabilizer; by introducing a styrene elastomer into the modified styrene elastomer layer, the prepared packaging film can have good chemical corrosion resistance and water vapor erosion resistance, and is not easy to slip during the preparation of photovoltaic modules, the auxiliary agent is not easy to precipitate, the shelf life is long, and the power attenuation due to wet heat aging is small, and the like can be effectively improved. The problem of power attenuation failure of TOPCon battery modules, especially single-glass TOPCon battery modules after high temperature and high humidity can be effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of photovoltaic cell components, and in particular relates to a synergistic double-layer co-extruded packaging adhesive film and a preparation method and application thereof. Background Art

[0002] As the efficiency of P-type PERC cells approaches the theoretical limit of 24.5%, the iteration of N-type cell technologies such as HJT and TOPCon has gradually accelerated. Among them, the advantages of TOPCon photovoltaic cells in terms of conversion efficiency and production costs have gradually become apparent. TOPCon cells are a type of solar cell technology. Its cell structure is an N-type silicon substrate cell. An ultra-thin layer of silicon oxide is prepared on the back, and then a thin layer of doped silicon is deposited. The two together form a passivated contact structure. Compared with P-type PERC cells, this structure has higher requirements for water vapor, pH, and stress performance, and is more sensitive.

[0003] At present, TOPCon photovoltaic cell modules, especially single-glass TOPCon photovoltaic cells, can basically only be encapsulated with low water permeability improved POE film. CN114806457A discloses a packaging film, especially a TOPCon battery-specific packaging film and its preparation method, and relates to the technical field of solar cell modules. The main material is: according to actual needs, choose: EVA resin 70-98 parts or POE resin 70-98 parts; auxiliary materials are: 0-3 parts of anti-aging additives, 0.3-2 parts of coupling agents, 0.5-3 parts of cross-linking agents, 0.2-2 parts of anti-PID additives, modified resins, 1-15 parts, processing aids: 0-5 parts. The resin modification technology is used to solve the problem of power attenuation caused by wet heat aging caused by the precipitation of POE film additives and the overflow of the packaging film; however, there are still some problems with POE film, such as low extrusion casting efficiency, serious slippage with glass and battery cells during component preparation, serious migration and precipitation of additives, and a shorter shelf life than EVA.

[0004] Styrene elastomers, such as SEEPS or SEBS, have good weather resistance, heat resistance, compression deformation resistance and excellent mechanical properties, and have excellent electrical properties and good solvent compatibility. They have good compatibility with various polyolefins and can be blended and modified. They are widely used in automotive components, wires and cables, polymer modifications and medical products.

[0005] Therefore, it is expected to develop a packaging film with good chemical corrosion resistance and water vapor erosion resistance, no slipping during component preparation, no precipitation of additives, long shelf life and small power attenuation due to wet and heat aging. Summary of the invention

[0006] In view of the deficiencies in the prior art, the object of the present invention is to provide a synergistic double-layer co-extruded packaging film and a preparation method and application thereof, wherein the packaging film comprises a styrene elastomer layer and a modified EVA layer. By introducing a styrene elastomer into the modified styrene elastomer layer, the prepared packaging film has good resistance to chemical corrosion and water vapor erosion, is not easy to slip during component preparation, the additive is not easy to precipitate, has a long shelf life and has the advantages of small power attenuation due to wet heat aging, etc., which can effectively improve TOPCon battery components, especially the power attenuation and failure problem of single-glass TOPCon battery components after high temperature and humidity.

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

[0008] In a first aspect, the present invention provides a synergistic double-layer co-extruded encapsulation film, the encapsulation film comprising a modified styrene elastomer layer and a modified EVA layer;

[0009] The raw materials for preparing the modified styrene-based elastomer layer include a styrene-based thermoplastic elastomer, a first initiator, a modifier and a first light stabilizer;

[0010] The raw materials for preparing the modified EVA layer include EVA resin, a second initiator, a crosslinking auxiliary agent, a second light stabilizer and an acid binding agent.

[0011] The synergistic double-layer co-extruded packaging film provided by the present invention comprises a modified styrene elastomer layer and a modified EVA layer. By introducing a styrene elastomer into the modified styrene elastomer layer, the good weather resistance, heat resistance and compression deformation resistance, as well as excellent mechanical properties and electrical properties of the styrene elastomer are utilized, and the good compatibility with various polyolefins and other materials is also utilized, so that the packaging film prepared by combining the styrene elastomer layer and the modified EVA layer has good chemical corrosion resistance and water vapor erosion resistance, and does not slip during component preparation, the additive does not precipitate, the shelf life is long, and the power attenuation due to wet heat aging is small, etc., which can effectively improve TOPCon battery components, especially the power attenuation failure problem of single-glass TOPCon battery components after high temperature and humidity.

[0012] Preferably, the raw materials for preparing the modified styrene elastomer layer include the following components in parts by weight:

[0013]

[0014] The first initiator may be in an amount of 0.5 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, or 4 parts by weight.

[0015] The modifier may be 0.5 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, etc.

[0016] The first light stabilizer may be 0.2 parts by weight, 0.5 parts by weight, 0.8 parts by weight, 1.2 parts by weight, 1.6 parts by weight, 1.9 parts by weight, etc.

[0017] Preferably, the styrene-based thermoplastic elastomer includes SEEPS and / or SEBS.

[0018] Preferably, the melt index of the styrene-based thermoplastic elastomer is 20 to 30 g / 10 min, for example, 22 g / 10 min, 24 g / 10 min, 26 g / 10 min or 28 g / 10 min.

[0019] Preferably, the melting point of the styrene-based thermoplastic elastomer is 90-115°C, for example, 92°C, 94°C, 96°C, 98°C, 100°C, 105°C or 110°C.

[0020] Preferably, the mass percentage of the styrene block in the styrene-based thermoplastic elastomer is 10-45%, for example, 15%, 20%, 25%, 30%, 35% or 40%.

[0021] Preferably, the first initiator comprises any one of diisopropylbenzene peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-bis(benzoylperoxy)-hexane, tert-amylperoxycarbonic acid-2-ethylethyl ester or tert-butylperoxy-2-ethylhexyl carbonate, or a combination of at least two thereof.

[0022] Preferably, the modifier comprises a combination of maleic anhydride and polypropylene.

[0023] Preferably, the mass ratio of maleic anhydride to polypropylene is 1:(0.5-1.5), for example, 1:0.7, 1:0.9, 1:1.1 or 1:1.3.

[0024] Preferably, the first light stabilizer comprises a hindered amine light stabilizer.

[0025] Preferably, the hindered amine light stabilizer includes any one of poly(1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidinyl) succinate, di(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, poly[[6-[(1,1,3,3-tetramethylbutyl)amine]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imine]-1,6-dihexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imine]]] or bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate or a combination of at least two thereof.

[0026] Preferably, the raw materials for preparing the modified styrene elastomer layer further include an antioxidant.

[0027] Preferably, the content of antioxidant in the raw materials for preparing the modified styrene elastomer layer is 0.1 to 2 parts by weight, for example, 0.2 parts by weight, 0.4 parts by weight, 0.6 parts by weight, 0.8 parts by weight, 1 part by weight, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight or 1.8 parts by weight.

[0028] Preferably, the antioxidant comprises any one of tris(2,4-di-tert-butylphenyl)phosphite, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate or pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, or a combination of at least two thereof.

[0029] Preferably, the raw materials for preparing the EVA layer include the following components in parts by weight:

[0030]

[0031] The second initiator may be in an amount of 0.1 parts by weight, 0.5 parts by weight, 1 part by weight, 1.5 parts by weight, 2 parts by weight, or 2.5 parts by weight.

[0032] The cross-linking aid may be 0.1 parts by weight, 0.5 parts by weight, 1 part by weight, 1.5 parts by weight, 2 parts by weight, or 2.5 parts by weight.

[0033] The second light stabilizer may be 0.03 parts by weight, 0.1 parts by weight, 0.5 parts by weight, 1 part by weight, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight, etc.

[0034] Preferably, the mass percentage of VA in the EVA resin is 10-30%, for example, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26% or 28%, and more preferably 10-20%.

[0035] Preferably, the melt index of the EVA resin is 6 to 30 g / 10 min, for example, 10 g / 10 min, 15 g / 10 min, 20 g / 10 min or 25 g / 10 min.

[0036] Preferably, the second initiator comprises a peroxide initiator.

[0037] Preferably, the peroxide initiator comprises any one of tert-butyl peroxy-2-ethylhexanoate, tert-amyl peroxy-2-ethylhexanoate, tert-butyl peroxy-trimethylhexanoate, tert-amyl peroxy-2-ethylethyl carbonate or tert-butyl peroxy-2-ethylhexyl carbonate, or a combination of at least two thereof.

[0038] Preferably, the cross-linking auxiliary agent includes any one of triallyl cyanurate, triallyl isocyanurate, trimethylolpropane triacrylate or trimethylolpropane trimethacrylate, or a combination of at least two thereof.

[0039] Preferably, the second light stabilizer comprises a hindered amine light stabilizer.

[0040] Preferably, the hindered amine light stabilizer includes any one of poly(1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidinyl) succinate, di(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, poly[[6-[(1,1,3,3-tetramethylbutyl)amine]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imine]-1,6-dihexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imine]]] or bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate or a combination of at least two thereof.

[0041] Preferably, the raw materials for preparing the EVA layer also include an acid binding agent.

[0042] Preferably, the content of the acid binding agent in the raw material for preparing the EVA layer is 0.01 to 1 part by weight, for example, 0.05 part by weight, 0.1 part by weight, 0.2 part by weight, 0.3 part by weight, 0.4 part by weight, 0.5 part by weight, 0.6 part by weight, 0.7 part by weight, 0.8 part by weight or 0.9 part by weight.

[0043] Preferably, the acid binding agent comprises a weak base.

[0044] Preferably, the weak base includes any one or a combination of at least two of N,N-diisopropylethylamine, carbodiimide, triethanolamine, tetrabutylammonium bromide, 4-dimethylaminopyridine, potassium carbonate, ammonium carbonate, sodium carbonate, magnesium hydroxide or magnesium carbonate.

[0045] Preferably, the raw materials for preparing the EVA layer also include a silane coupling agent.

[0046] Preferably, the content of silane coupling agent in the raw material for preparing the EVA layer is 0.01 to 2 parts by weight, for example, 0.1 parts by weight, 0.5 parts by weight, 1 part by weight, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight or 1.8 parts by weight.

[0047] Preferably, the silane coupling agent includes any one of methacryloxysilane, aminopropyltriethoxysilane or glycidyloxypropylsilane, or a combination of at least two thereof.

[0048] Preferably, the thickness of the modified styrene elastomer layer is 0.1-0.5 mm, for example, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm or 0.45 mm.

[0049] Preferably, the thickness of the EVA layer is 0.1-0.5 mm, for example, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm or 0.45 mm.

[0050] Preferably, the packaging film has a thickness of 0.2-1 mm, for example, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm or 0.9 mm.

[0051] In a third aspect, the present invention provides a method for preparing the encapsulation film according to the first aspect, characterized in that the preparation method comprises the following steps:

[0052] (1) mixing a styrene-based thermoplastic elastomer, a first initiator, a modifier, a first light stabilizer and optionally an antioxidant, extruding and granulating to obtain a modified styrene-based elastomer masterbatch; mixing an EVA resin, a second initiator, a crosslinking aid, a second light stabilizer, optionally an acid-binding agent and optionally a silane coupling agent, extruding and granulating to obtain a modified EVA masterbatch;

[0053] (2) Extruding the modified styrene elastomer masterbatch and the modified EVA masterbatch obtained in step (1), casting them into a film, and obtaining the encapsulating film.

[0054] Preferably, the extrusion granulation in step (1) is carried out in a twin-screw extruder.

[0055] Preferably, after the mixing in step (1) is completed, a standing step is also included.

[0056] Preferably, the extrusion in step (2) is carried out in a twin-screw extruder.

[0057] Preferably, the film casting in step (2) is carried out in a multi-layer co-extrusion die.

[0058] In a third aspect, the present invention provides a use of the encapsulation film as described in the first aspect in a photovoltaic cell assembly.

[0059] Preferably, the photovoltaic module is a TOPCon photovoltaic cell module.

[0060] Preferably, the TOPCon photovoltaic cell module is a single-glass TOPCon cell module.

[0061] Compared with the prior art, the present invention has the following beneficial effects:

[0062] (1) The synergistic double-layer co-extruded packaging film provided by the present invention comprises a modified styrene elastomer layer and a modified EVA layer. By introducing a styrene elastomer into the modified styrene elastomer layer, the prepared packaging film has good chemical corrosion resistance and water vapor erosion resistance, and does not slip during component preparation, does not precipitate additives, has a long shelf life, and has the advantages of small power attenuation due to wet heat aging. It can effectively improve the TOPCon battery module, especially the power attenuation failure problem of the single-glass TOPCon battery module after high temperature and high humidity.

[0063] (2) By further optimizing the raw materials for preparing the modified styrene elastomer layer and the modified EVA layer, the light transmittance of the provided encapsulation film can be 92.31-92.61%, the acid value can be 147-252 ug / g, and the volume resistivity can be 1.2-2.4×10 17 Ohm·cm, the initial peel strength is 128~154N / cm and the peel strength after DH1000 h is 101~114N / cm. The power attenuation of the further prepared TOPCon battery component HAST96h is 1.85~3.54%, and the power attenuation of DH1000 h is 1.89~4.02%. DETAILED DESCRIPTION

[0064] The technical solution of the present invention is further described below by specific implementation methods. 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.

[0065] Example 1

[0066] A synergistic double-layer co-extruded packaging film with a thickness of 0.5 mm, comprising a modified styrene elastomer layer and a modified EVA layer with a thickness ratio of 1:1;

[0067] The method for preparing the packaging film comprises the following steps:

[0068] (1) 100 parts by weight of SEBS resin (melt index of 22 g / 10 min, melting point of 96° C., mass percentage of styrene block of 13%), 2 parts by weight of diisopropylbenzene peroxide, 3 parts by weight of maleic anhydride, 1 part by weight of low molecular weight and low modulus polypropylene (molecular weight of 130,000, melting point of 80° C., tensile modulus of 10 MPa), 0.3 parts by weight of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and 0.2 parts by weight of di(2,2,6,6-tetramethyl-4-piperidinyl) sebacate were mixed at a temperature of 60° C. and a stirring speed of 20 rpm for 50 min to ensure uniform mixing, and then placed in a twin-screw extruder for extrusion at an extrusion temperature of 160° C., cooled and pelletized to obtain a SEBS masterbatch;

[0069] 100 parts by weight of EVA resin (melt index of 20 g / 10 min, mass percentage of VA of 18%), 1 part by weight of tert-amyl peroxycarbonic acid-2-ethyl ethyl ester, 1 part by weight of triallyl isocyanurate, 1 part by weight of trimethylolpropane triacrylate, 0.5 part by weight of γ-methacryloxypropyl trimethoxysilane, 0.2 part by weight of di(2,2,6,6-tetramethyl-4-piperidinyl) sebacate and 0.1 part by weight of magnesium hydroxide were mixed at a temperature of 60° C. and a stirring speed of 20 rpm for 60 min to ensure uniform stirring and mixing, and then put into a twin-screw extruder after standing for 12 h, extruded at an extrusion temperature of 100° C., cooled and pelletized to obtain EVA masterbatch;

[0070] (2) The SEBS masterbatch and the EVA masterbatch obtained in step (1) are put into a twin-screw cast extruder, and the thickness ratio of the SEBS layer and the EVA layer is ensured to be 1:1 through a co-extrusion die. After casting, embossing, cooling, pulling, and winding, the encapsulation film is prepared.

[0071] Example 2

[0072] A synergistic double-layer co-extruded packaging film, which differs from Example 1 only in that SEEPS resin with a melt index of 22g / 10min, a melting point of 90°C, and a styrene block mass percentage of 16% is used to replace SEBS resin, and other structures, materials and preparation methods are the same as those in Example 1.

[0073] Example 3

[0074] A synergistic double-layer co-extruded packaging film, which differs from Example 1 in that an EVA resin with a melt index of 25 g / 10 min and a VA mass percentage of 28% is used to replace the EVA resin with a melt index of 20 g / 10 min and a VA mass percentage of 18%, and no magnesium hydroxide is added. Other structures, materials and preparation methods are the same as those in Example 1.

[0075] Example 4

[0076] A synergistic double-layer co-extruded packaging film, which differs from Example 1 in that SEEPS resin with a melt index of 22 g / 10 min, a melting point of 90°C, and a styrene block mass percentage of 16% is used to replace SEBS resin, and EVA resin with a melt index of 25 g / 10 min and a VA mass percentage of 28% is used to replace EVA resin with a melt index of 20 g / 10 min and a VA mass percentage of 18%, and no magnesium hydroxide is added. Other structures, materials and preparation methods are the same as those in Example 1.

[0077] Example 5

[0078] A synergistic double-layer co-extruded packaging film is different from Example 1 only in that maleic anhydride is not added, the addition amount of low molecular weight and low modulus polypropylene is 4 parts by weight, and the other structures, materials and preparation methods are the same as those of Example 1.

[0079] Comparative Example 1

[0080] A packaging film is different from Example 1 only in that POE resin with a melt index of 14 g / 10 min and a mass percentage of octene of 30% is used to replace SEBS resin, and other structures, materials and preparation methods are the same as those of Example 1.

[0081] Comparative Example 2

[0082] A co-extruded packaging film with a conventional EPE structure on the market, specifically the T22H product of Suzhou Saiwu Company.

[0083] Comparative Example 3

[0084] A conventional POE encapsulation film on the market, specifically the T22 product of Saiwu Company.

[0085] Comparative Example 4

[0086] A packaging film, which differs from Example 1 only in that no modified styrene elastomer layer is provided, only an EVA layer is included, and the thickness is 0.5 mm. Other structures, materials and preparation methods are the same as those of Example 1.

[0087] Performance Test:

[0088] (1) Light transmittance: Tested in accordance with the light transmittance method in the national standard GBT2410-2008 "Determination of light transmittance and haze of transparent plastics";

[0089] (2) Volume resistivity: Tested in accordance with GB / T1410-200 "Test method for volume resistivity and surface resistivity of solid insulating materials";

[0090] (3) Peel strength: Tested in accordance with GB / T2790-1995 "Test method for 180° peel strength of adhesives". All backsheets use CPC structure backsheets, and the glass uses ultra-clear photovoltaic patterned glass.

[0091] (4) Acid value: Tested according to the test method in the patent "Test and Evaluation of Corrosion Resistance of Encapsulation Film for Photovoltaic Modules" (Patent No. CN115406824 A).

[0092] The encapsulation films provided in Examples 1 to 6 and Comparative Examples 1 to 4 were tested according to the above test method. The test results are shown in Table 1:

[0093] Table 1 Performance test results of embodiments and comparative examples

[0094]

[0095] According to the data in Table 1, we can see that:

[0096] The light transmittance of the encapsulation films provided in Examples 1 to 4 is 92.31 to 92.61%, the acid value is 147 to 252 ug / g, and the volume resistivity is 1.2 to 2.4×10 17 Ohm·cm, initial peel strength of 128-154N / cm, and peel strength of 101-114N / cm after DH1000 h.

[0097] By comparing the data of Example 1 and Comparative Examples 1 to 4, it can be seen that the peel strength and volume resistivity of the encapsulation films provided by Comparative Examples 1 to 3 after wet heat aging DH 1000h are significantly lower than those of Example 1; while the acid value of the encapsulation film provided by Comparative Example 4 is significantly higher than that of Example 1, and the volume resistivity is significantly lower than that of Example 1.

[0098] By comparing the data of Examples 1-2 and Examples 3-4, it can be seen that the acid value of the packaging film of Examples 1-2 with the acid binding agent added is significantly lower than that of the packaging film of Examples 3-4 without the acid binding agent added.

[0099] Comparing the data of Example 1 and Example 5, it can be seen that the initial bonding force of the encapsulation film provided by Example 5 is less than that of Example 1, indicating that the addition of maleic anhydride grafting modification has an improvement effect on the initial bonding force;

[0100] In summary, it can be seen that the present invention can effectively reduce the acid value of the packaging film and increase the peeling strength of the packaging film with glass after wet-heat aging by introducing styrene elastomers SEEPS and SEBS into the packaging film.

[0101] (5) In order to compare and illustrate the effects of different encapsulation films on the performance of the prepared TOPCon battery modules, the TOPCon battery modules were encapsulated and prepared using various encapsulation films according to the conventional method. The specific steps include: stacking from bottom to top to obtain a pre-laminated part, the order is: photovoltaic ultra-white embossed coated glass, encapsulation film, TOPCon crystalline silicon cell, encapsulation film and CPC structure photovoltaic backplane; then placing the stacked pre-laminated part into a vacuum laminator for lamination, the lamination temperature is 147°C, the vacuum time is 4 minutes, and the pressure holding time is 15 minutes. The photovoltaic module laminate obtained by the lamination packaging process is cooled, trimmed, framed and connected to a junction box to obtain a photovoltaic module, and its power attenuation after HAST 96h and DH 1000h is tested. The test method refers to IEC60904-1:2006. The test results are shown in Table 2:

[0102] Table 2 TOPCon battery module test results corresponding to different encapsulation films

[0103]

[0104]

[0105] According to the data in Table 2, we can see that:

[0106] The power attenuation of the TOPCon battery assembly HAST 96h further prepared by the encapsulation films provided in Examples 1 to 4 is 1.85-3.54%, and the power attenuation of the DH1000h is 1.89-4.02%.

[0107] From the data of Example 1 and Comparative Examples 1 to 4, it can be seen that the moisture and heat resistance of the TOPCon battery assembly further prepared by introducing SEEPS resin or SEBS resin into the encapsulation film provided by the present invention is significantly improved, and the HAST 96h and DH1000h power reductions meet the standard requirement of <5%; while the TOPCon battery single-glass assembly further prepared by using conventional POE, EP, EPE and EVA encapsulation films provided by the data of Comparative Examples 1 to 4 has poor moisture and heat aging resistance, and the HAST 96h and DH1000h power attenuation are greater than the minimum standard requirement of 5%.

[0108] Comparing the data of Examples 1-2 and Examples 3-4, it can be seen that the wet heat aging resistance of the encapsulation film of Examples 1-2 with an acid binding agent is significantly better than that of the encapsulation film of Examples 3-4 without an acid binding agent.

[0109] Comparing the data of Example 1 and Example 5, it can be seen that the packaging film of Example 5 without maleic anhydride grafting modification delaminated and had water ingress at the edge after the HAST96h test.

[0110] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate a synergistic double-layer co-extruded encapsulation film and its preparation method and application, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments 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 synergistic double-layer co-extruded packaging film, characterized in that: The packaging film comprises a modified styrene elastomer layer and a modified EVA layer; The raw materials for preparing the modified styrene-based elastomer layer include a styrene-based thermoplastic elastomer, a first initiator, a modifier and a first light stabilizer; The styrene-based thermoplastic elastomer consists of SEEPS and / or SEBS; The modifier consists of a combination of maleic anhydride and polypropylene; The raw materials for preparing the modified EVA layer include EVA resin, a second initiator, a crosslinking aid and a second light stabilizer.

2. The packaging film according to claim 1, characterized in that: The raw materials for preparing the modified styrene elastomer layer include the following components in parts by weight: 100 parts by weight of styrene-based thermoplastic elastomer The first initiator 0.1-5 parts by weight Modifier 0.1~5 parts by weight The first light stabilizer is 0.1 to 2 parts by weight.

3. The packaging film according to claim 1, characterized in that: The melt index of the styrene-based thermoplastic elastomer is 20-30 g / 10min.

4. The packaging film according to claim 1, characterized in that: The melting point of the styrene-based thermoplastic elastomer is 90-115°C.

5. The packaging film according to claim 1, characterized in that: The mass percentage of styrene blocks in the styrene-based thermoplastic elastomer is 10-45%.

6. The packaging film according to claim 1, characterized in that: The first initiator includes any one of diisopropylbenzene peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-bis(benzoylperoxy)-hexane, tert-amylperoxycarbonic acid-2-ethylethyl ester or tert-butylperoxy-2-ethylhexyl carbonate, or a combination of at least two thereof.

7. The packaging film according to claim 1, characterized in that: The mass ratio of maleic anhydride to polypropylene is 1:(0.5-1.5).

8. The packaging film according to claim 1, characterized in that: The first light stabilizer includes a hindered amine light stabilizer.

9. The packaging film according to claim 8, characterized in that: The hindered amine light stabilizer includes any one of poly(1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidinyl) succinate, di(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, poly[[6-[(1,1,3,3-tetramethylbutyl)amine]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imine]-1,6-dihexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imine]]] or bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate or a combination of at least two thereof.

10. The packaging film according to claim 1, characterized in that: The raw materials for preparing the modified styrene-based elastomer layer also include an antioxidant.

11. The packaging adhesive film according to claim 10, characterized in that: The content of the antioxidant is 0.1-2 parts by weight.

12. The packaging adhesive film according to claim 11, characterized in that: The antioxidant includes any one of tris(2,4-di-tert-butylphenyl)phosphite, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, or pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, or a combination of at least two thereof.

13. The packaging film according to claim 1, characterized in that: The raw materials for preparing the modified EVA layer include the following components in parts by weight: EVA resin 100 parts by weight The second initiator 0.05-3 parts by weight Crosslinking aid 0.05~5 parts by weight The second light stabilizer is 0.01 to 2 parts by weight.

14. The packaging film according to claim 1, characterized in that: The mass percentage of VA in the EVA resin is 10-30%.

15. The packaging film according to claim 14, characterized in that: The mass percentage of VA in the EVA resin is 10-20%.

16. The packaging film according to claim 1, characterized in that: The melt index of the EVA resin is 6-30 g / 10min.

17. The packaging film according to claim 1, characterized in that: The second initiator comprises a peroxide initiator.

18. The packaging adhesive film according to claim 17, characterized in that: The peroxide initiator includes any one of tert-butyl peroxy-2-ethylhexanoate, tert-amyl peroxy-2-ethylhexanoate, tert-butyl peroxy-trimethylhexanoate, tert-amyl peroxy-2-ethylethyl carbonate or tert-butyl peroxy-2-ethylhexyl carbonate, or a combination of at least two thereof.

19. The packaging film according to claim 1, characterized in that: The cross-linking auxiliary agent includes any one of triallyl cyanurate, triallyl isocyanurate, trimethylolpropane triacrylate or trimethylolpropane trimethacrylate, or a combination of at least two thereof.

20. The packaging adhesive film according to claim 1, characterized in that: The second light stabilizer includes a hindered amine light stabilizer.

21. The packaging adhesive film according to claim 20, characterized in that: The hindered amine light stabilizer includes any one of poly(1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidinyl) succinate, di(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, poly[[6-[(1,1,3,3-tetramethylbutyl)amine]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imine]-1,6-dihexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imine]]] or bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate or a combination of at least two thereof.

22. The packaging film according to claim 1, characterized in that: The raw materials for preparing the modified EVA layer also include an acid binding agent.

23. The packaging adhesive film according to claim 22, characterized in that: The content of the acid binding agent in the raw materials for preparing the modified EVA layer is 0.01 to 1 parts by weight.

24. The packaging adhesive film according to claim 22, characterized in that: The acid binding agent includes a weak base.

25. The packaging adhesive film according to claim 24, characterized in that: The weak base includes any one or a combination of at least two of N,N-diisopropylethylamine, carbodiimide, triethanolamine, tetrabutylammonium bromide, 4-dimethylaminopyridine, potassium carbonate, ammonium carbonate, sodium carbonate, magnesium hydroxide or magnesium carbonate.

26. The packaging film according to claim 1, characterized in that: The raw materials for preparing the modified EVA layer also include a silane coupling agent.

27. The packaging adhesive film according to claim 26, characterized in that: The content of the silane coupling agent in the raw materials for preparing the modified EVA layer is 0.01 to 2 parts by weight.

28. The packaging adhesive film according to claim 27, characterized in that: The silane coupling agent includes any one of methacryloxysilane, aminopropyltriethoxysilane or glycidyloxypropylsilane or a combination of at least two thereof.

29. The packaging film according to claim 1, characterized in that: The thickness of the modified styrene elastomer layer is 0.1-0.5 mm.

30. The packaging film according to claim 1, characterized in that: The thickness of the modified EVA layer is 0.1-0.5 mm.

31. The packaging film according to claim 1, characterized in that: The thickness of the packaging film is 0.2-1 mm.

32. A method for preparing the encapsulation film according to any one of claims 1 to 31, characterized in that: The preparation method comprises the following steps: (1) mixing a styrene thermoplastic elastomer, a first initiator, a modifier, a first light stabilizer and an optional antioxidant, extruding and granulating to obtain a modified styrene elastomer masterbatch; mixing an EVA resin, a second initiator, a crosslinking aid, a second light stabilizer, an optional acid-binding agent and an optional silane coupling agent, extruding and granulating to obtain a modified EVA masterbatch; (2) The modified styrene elastomer masterbatch and the modified EVA masterbatch obtained in step (1) are co-extruded and cast into a film to obtain the encapsulating film.

33. The preparation method according to claim 32, characterized in that: The extrusion granulation in step (1) is carried out in a twin-screw extruder.

34. The preparation method according to claim 32, characterized in that: After the mixing in step (1) is completed, the method further includes a step of standing.

35. The preparation method according to claim 32, characterized in that: The extrusion in step (2) is carried out in a twin-screw extruder.

36. The preparation method according to claim 32, characterized in that: The film casting in step (2) is carried out in a multi-layer co-extrusion die.

37. Use of the encapsulation film according to any one of claims 1 to 31 in a photovoltaic cell assembly.

38. The use according to claim 37, characterized in that The photovoltaic module is a TOPCon photovoltaic cell module.

39. The use according to claim 38, characterized in that The TOPCon photovoltaic cell module is a single-glass TOPCon cell module.

Images