Polyethylene elastomer composition for photovoltaic adhesive film as well as preparation method and application of polyethylene elastomer composition

Abstract

The invention discloses a polyethylene elastomer composition for a photovoltaic adhesive film as well as a preparation method and application of the polyethylene elastomer composition, and the composition comprises the following components in parts by weight: 100 parts of matrix resin, 0.3-3 parts of a main crosslinking agent, 0.3-3 parts of an assistant crosslinking agent, 0.05-3 parts of a silane coupling agent, 0.05-0.5 part of an antioxidant and 0.1-0.3 part of a light stabilizer. The photovoltaic adhesive film prepared from the polyethylene elastomer composition is of a single-layer structure, and the packaging performance of the photovoltaic adhesive film is close to or superior to that of a commercial POE photovoltaic adhesive film.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cells, in particular to the technical field of photovoltaic films, and relates to a polyethylene elastomer composition for photovoltaic films, a preparation method thereof, and an application thereof. Background Art

[0002] The photovoltaic industry plays a vital role in global energy transformation and climate change response. With technological advancements and cost reductions, photovoltaic power generation has become the main source of incremental power generation and is expected to become the main source of existing capacity. Existing photovoltaic power generation systems mainly consist of three major parts: solar panels (also known as solar cell modules or photovoltaic modules), controllers, and inverters. Photovoltaic film is an indispensable encapsulation material in solar cell modules. It is located between the cell and the glass or backplane, bonding the cell, blocking moisture, and protecting the cell. The quality of photovoltaic film is directly related to the reliability and long-term stability of photovoltaic modules. Therefore, manufacturers and policymakers attach great importance to the performance and quality of photovoltaic film.

[0003] In the 1980s, ethylene-vinyl acetate (EVA) film became a mainstream encapsulation material in the market due to its excellent optical properties, adhesion, and relatively low price. However, EVA film has a high water vapor permeability and is susceptible to accelerated aging under external influences. The acetic acid produced by degradation accumulates within the module, causing corrosion at joints, yellowing, and potential-induced degradation (PID) effects, which in turn seriously impact the stable operation and lifecycle of photovoltaic power generation systems. To overcome the reliability issues of photovoltaic modules caused by EVA degradation, polyolefin elastomer (POE) film has begun to attract attention as an alternative encapsulation material that can prevent PID effects. The polymer chain of commercially available POE features randomly distributed ethylene and α-olefin units. The addition of a certain amount of α-olefin gives POE products both high elasticity and thermoplastic properties. Due to its unique molecular structure, it exhibits superior heat resistance, chemical resistance, UV resistance, and PID resistance compared to EVA in extreme environments. It is currently widely used in the production of high-value-added products such as photovoltaic modules, automotive parts, and wire and cable. However, the technical barriers to POE production are high, requiring specific polymerization technology and equipment. In addition, the raw material high-carbon α-olefins rely on imports, are expensive and in short supply, making the cost of POE film much higher than that of EVA film.

[0004] As the photovoltaic market enters the "post-parity era," while the cost of photovoltaic power generation is gradually decreasing, finding affordable alternative materials for photovoltaic modules remains challenging. The high cost of POE film compared to traditional EVA film has become a major bottleneck for its large-scale adoption. As the photovoltaic industry's requirements for the lifespan and stability of photovoltaic modules increase, the need to balance material performance with economic costs becomes increasingly urgent. Reducing the cost of encapsulation films while meeting the stringent electrical insulation and water vapor barrier properties required by photovoltaic modules and ensuring the efficient use of solar energy has become a pressing challenge for the industry. Summary of the Invention

[0005] In order to solve the technical problem that the existing POE film is too expensive and cannot meet the large-scale application in the market, the present invention provides a polyethylene elastomer composition for photovoltaic film and its preparation method and application.

[0006] Specifically, the present invention adopts the following technical solutions:

[0007] A polyethylene elastomer composition for photovoltaic films comprises, by weight, 100 parts of a base resin, 0.3-3 parts of a primary cross-linking agent, 0.3-3 parts of an auxiliary cross-linking agent, 0.05-3 parts of a silane coupling agent, 0.05-0.5 parts of an antioxidant, and 0.1-0.3 parts of a light stabilizer; wherein the base resin is selected from a polyethylene elastomer, and the raw material of the polyethylene elastomer does not contain α-olefin.

[0008] According to an embodiment of the present invention, the base resin is a polyethylene elastomer; the polyethylene elastomer is obtained by catalytic polymerization of ethylene monomer in the presence of a nickel-based catalyst and a co-catalyst. Specifically, the raw materials used to prepare the polyethylene elastomer do not contain α-olefins, and the polyethylene elastomer is composed of hyperbranched polyethylene.

[0009] According to an embodiment of the present invention, the nickel-based catalyst includes at least one of an α-diimine nickel complex catalyst, a pyridocycloheptaneimine nickel complex catalyst, and a fluorobenzhydryl-modified α-diimine nickel complex catalyst. For details, reference may be made to patents CN102180910B, CN108794545B, CN105646599B, CN105693896B, and CN104387424B.

[0010] According to an embodiment of the present invention, the cocatalyst includes one or more of methylaluminoxane, triisobutylaluminum-modified methylaluminoxane, diethylaluminum chloride, dimethylaluminum chloride, sesquiethylaluminum chloride, and ethylaluminum dichloride.

[0011] According to an embodiment of the present invention, the molar ratio of the metal Al in the co-catalyst to the central metal Ni of the nickel complex is (20-8000):1, preferably (100-4500):1, and further preferably (300-1200):1.

[0012] According to an embodiment of the present invention, the temperature of the catalytic polymerization reaction is 20 to 150° C., preferably 20 to 100° C., the pressure is 1 atm to 15 atm, and the reaction time is 0.1 to 16 hours.

[0013] According to an embodiment of the present invention, the catalytic polymerization reaction is carried out in the presence of an organic solvent, and the organic solvent is selected from one or more of n-hexane, cyclohexane, toluene, o-xylene, dichloromethane, ethanol, tetrahydrofuran, n-heptane, and cycloheptane, preferably n-hexane. In the present invention, the content of the organic solvent is not particularly limited, as long as it can dissolve the raw materials.

[0014] According to an embodiment of the present invention, the branching degree of the base resin is 70 to 150B / 1000C, preferably 85 to 120B / 1000C, and further preferably 100 to 120B / 1000C.

[0015] According to an embodiment of the present invention, the weight average molecular weight of the base resin is 1×10 4 ~100×10 4 g·mol -1 , preferably 2×10 4 ~20×10 4 ; Also preferably 5×10 4 ~8×10 4 ; The molecular weight distribution is between 1.7 and 2.5.

[0016] According to the embodiment of the present invention, according to the test method specified in GB / T 1033.1, the density of the matrix resin is 0.850 g / cm 3 ~0.900g / cm 3 , preferably 0.860 g / cm 3 ~0.880g / cm 3 , for example 0.865 g / cm 3 ~0.875g / cm 3 .

[0017] According to an embodiment of the present invention, according to the test method specified in GB / T 1845.1, at 190°C / 2.16kg, the melt index (MI) of the matrix resin is 14g / 10min-20g / 10min, preferably 16g / 10min-20g / 10min.

[0018] According to an embodiment of the present invention, the melting point of the matrix resin is 50-90°C, preferably 50-80°C, for example 55-65°C, and for example 58-64°C.

[0019] According to an embodiment of the present invention, the glass transition temperature (Tg) of the base resin is -45°C to -60°C.

[0020] According to an embodiment of the present invention, the tensile strength of the matrix resin is 8-15 MPa, preferably 9-12 MPa.

[0021] According to an embodiment of the present invention, the elongation at break of the base resin is 1200-1600%, preferably 1225-1500%.

[0022] According to an embodiment of the present invention, the main cross-linking agent is a mixture of one or more of tert-butyl peroxyisopropyl carbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-butyl peroxycarbonate-2-ethylhexyl ester, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-amyl peroxycarbonate, tert-butyl peroxy-3,3,5-trimethylhexanoate and 1,3-bis-(2-tert-butylperoxyisopropyl).

[0023] According to an embodiment of the present invention, the content of the primary cross-linking agent is 0.5 to 3 parts, for example, 0.5 parts, 1.0 parts, 1.5 parts, 2.0 parts, or 2.5 parts.

[0024] According to an embodiment of the present invention, the auxiliary cross-linking agent is a mixture of one or more of triallyl isocyanate (e.g., triallyl isocyanurate), trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, trimethallyl isocyanate, trimethylolpropane trimethacrylate, and pentaerythritol triacrylate.

[0025] According to an embodiment of the present invention, the content of the auxiliary cross-linking agent is 0.5 to 3 parts, for example, 0.5 parts, 1.0 parts, 1.5 parts, 2.0 parts, or 2.5 parts.

[0026] According to an embodiment of the present invention, the silane coupling agent is a mixture of one or more of γ-methacryloxypropylmethyltrimethoxysilane, γ-glycidylpropyltrimethoxysilane, 3-aminopropyltriethoxysilane, tristearoyl titanate isopropyl, isopropyl tris(dioctyl pyrophosphate) titanate, glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, and vinyl-tris(2-methoxyethoxy) silane.

[0027] According to an embodiment of the present invention, the content of the silane coupling agent is 0.05 to 2.5 parts, for example, 0.05 parts, 0.1 parts, 0.5 parts, 1.0 parts, 1.5 parts, 2.0 parts, or 2.5 parts.

[0028] According to an embodiment of the present invention, the antioxidant is a mixture of one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris[2,4-di-tert-butylphenyl]phosphite and N,N'-1,6-hexanediylbis(3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionyl).

[0029] According to an embodiment of the present invention, the content of the antioxidant is 0.05 to 0.2 parts, for example, 0.05 parts, 0.1 parts, 0.15 parts or 0.2 parts.

[0030] According to an embodiment of the present invention, the light stabilizer is at least one of bis-2,2,6,6-tetramethylpiperidinol sebacate, 2,2,6,6-tetramethyl-4-piperidinyl ester, tetramethylpiperidone, and 1,5,8,12-tetra[4,6-bis(N-butyl-N-1,2,2,6,6-pentamethyl-4-piperidinylamino)-1,3,5-triazine-2-yl]-1,5,8,12-tetraazadodecane.

[0031] According to an embodiment of the present invention, the content of the light stabilizer is 0.15 to 0.3 parts, for example, 0.15 parts, 0.20 parts, 0.25 parts or 0.3 parts.

[0032] The present invention also provides a method for preparing the polyethylene elastomer composition, the preparation steps comprising:

[0033] (1) mixing a main cross-linking agent, an auxiliary cross-linking agent, an antioxidant, a light stabilizer, and a silane coupling agent in proportion to obtain an auxiliary agent solution;

[0034] (2) The additive solution is dispersed in the matrix resin, and the obtained mixture is subjected to a casting process to prepare a polyethylene elastomer composition.

[0035] Furthermore, in step (1), the mixing temperature is 70-90° C., for example, 70° C., 80° C., or 90° C. The mixing time is 0.5-4 h, for example, 0.5 h, 1 h, 1.5 h, 2 h, 3 h, or 4 h.

[0036] Furthermore, the casting treatment temperature is 90-120°C, for example, 90°C, 100°C, 110°C, or 120°C.

[0037] The present invention also provides an application of the polyethylene elastomer composition described above in the field of photovoltaic packaging.

[0038] Preferably, the polyethylene elastomer composition is used as a photovoltaic film; more specifically, the photovoltaic film is used as an encapsulation material in a photovoltaic module.

[0039] The present invention also provides a photovoltaic adhesive film, the raw material of which is the above-mentioned polyethylene elastomer composition.

[0040] According to an embodiment of the present invention, the photovoltaic adhesive film is a cast film of the above-mentioned polyethylene elastomer composition.

[0041] According to an embodiment of the present invention, the photovoltaic adhesive film has a single-layer structure.

[0042] The present invention also provides application of the photovoltaic adhesive film in photovoltaic modules.

[0043] Specifically, the photovoltaic adhesive film is used as a packaging material in photovoltaic modules.

[0044] Beneficial effects of the present invention:

[0045] (1) The present invention provides a polyethylene elastomer composition for photovoltaic film, wherein the base resin is selected from polyethylene elastomer, and the polyethylene elastomer is prepared by polymerization of only a single ethylene raw material through a Ni-based catalyst, without the need to add expensive α-olefins, and the raw material cost is at least 30% lower than that of commercial POE.

[0046] (2) The base resin in the polyethylene elastomer composition of the present invention is selected from polyethylene elastomer. The non-polar structure of the pure hydrocarbon in the polyethylene elastomer gives it excellent water vapor barrier capability, high light transmittance and insulation properties, and physical and chemical properties that are close to or better than those of commercial POE raw materials. It also has high fluidity, excellent adhesion, and balanced mechanical properties. After further adjustment, it can adapt to the packaging requirements of N-type TOPCon batteries, HJT batteries, and large-size silicon wafer batteries.

[0047] (3) The photovoltaic film prepared from the polyethylene elastomer composition of the present invention has a single-layer structure, and its packaging performance is close to or better than that of commercial POE photovoltaic film. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 Schematic diagram of the structure of a small double-glass photovoltaic module prepared from the polyethylene elastomer composition of Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0049] The technical solutions of the present invention will be described in further detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are encompassed within the scope of protection that the present invention is intended to protect.

[0050] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0051] Example 1

[0052] Preparation of polyethylene elastomer:

[0053] Under an ethylene atmosphere, 25 L of n-hexane was added to a 50 L autoclave. The ethylene pressure in the autoclave was raised to 10 atm. After the system temperature reached 70°C, 10 mL of a 20 μmol toluene solution of a nickel-α-diimine complex catalyst, 6 mL of a 1 mol / L toluene solution of a co-catalyst, ethylaluminum sesquichloride, and 200 mL of n-hexane were added sequentially to the autoclave, achieving an Al / Ni ratio of 600:1. The reaction system temperature was maintained at 70°C and the ethylene pressure at a constant 10 atm. After 30 minutes of reaction, stirring was stopped and the reaction mixture was neutralized with a 10% ethanolic hydrochloric acid solution to obtain a polymer precipitate. After washing several times with ethanol, the precipitate was dried under vacuum to a constant weight, yielding a polyethylene elastomeric polymer, i.e., the matrix resin.

[0054] In this embodiment 1, the polyethylene elastomer composition comprises: 100 parts of polyethylene elastomer resin; the primary crosslinking agents are tert-amyl peroxycarbonate and tert-butyl peroxycarbonate, added in amounts of 0.3 parts and 0.3 parts, respectively; the auxiliary crosslinking agent is triallyl isocyanurate, added in an amount of 1 part; the silane coupling agent is γ-methacryloxypropylmethyltrimethoxysilane, added in an amount of 1 part; the light stabilizer is bis-2,2,6,6-tetramethylpiperidinol sebacate, added in an amount of 0.20 part; and the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, added in an amount of 0.05 part. The polyethylene elastomer mixture is added to the hopper of a casting extruder, the extrusion temperature is controlled at 100°C, and the parameters are set according to conventional process conditions. The polyethylene elastomer photovoltaic film (i.e., the polyethylene elastomer composition) is produced through plasticizing, extrusion, casting, drawing, and winding.

[0055] Example 2

[0056] The polyethylene elastomer was prepared by a method substantially the same as that of Example 1, except that the polymerization temperature was 72°C.

[0057] In this Example 2, the photovoltaic encapsulation film is prepared by the same method as in Example 1, except that the base resin is different, and the added main cross-linking agent, auxiliary cross-linking agent, silane coupling agent, light stabilizer and antioxidant are the same.

[0058] Example 3

[0059] The polyethylene elastomer was prepared by a method substantially the same as that of Example 1, except that the polymerization temperature was 75°C.

[0060] In this Example 3, the photovoltaic encapsulation film is prepared by the same method as in Example 1, except that the base resin is different, and the added main cross-linking agent, auxiliary cross-linking agent, silane coupling agent, light stabilizer and antioxidant are the same.

[0061] Comparative Example 1

[0062] In Comparative Example 1, the polyolefin elastomer mixture comprises: 100 parts of polyolefin elastomer resin, 0.3 parts of tert-amyl peroxycarbonate and 0.3 parts of tert-butyl peroxycarbonate-2-ethylhexyl, respectively, as crosslinkers, 1 part of triallyl isocyanurate as a co-crosslinker, 1 part of γ-methacryloxypropyltrimethoxysilane as a silane coupling agent, 0.20 parts of bis-2,2,6,6-tetramethylpiperidinol sebacate as a light stabilizer, and 0.05 parts of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] as an antioxidant. The polyolefin elastomer resin comprises 75% POE (Dow Chemical, POE-8669) and 25% POE (Dow Chemical, POE-8660). The polyolefin elastomer mixture is added into the hopper of the cast extruder, the extrusion temperature is controlled at 100°C, and the parameters are set according to conventional process conditions. The POE photovoltaic film is made through plasticizing extrusion, casting, pulling and winding.

[0063] Comparative Example 2

[0064] In this comparative example 2, a photovoltaic encapsulation film is prepared by the same method as in comparative example 1, except that the base resin is a polyolefin elastomer resin POE (Dow, USA, POE-8669), and the added main cross-linking agent, auxiliary cross-linking agent, silane coupling agent, light stabilizer and antioxidant are all the same.

[0065] Performance testing

[0066] The properties of the polyethylene elastomers obtained in Examples 1 to 3 and the commercial polyolefin elastomers of Comparative Examples 1 to 2 were tested, and the test results are shown in Table 1. The density of the base resin was tested according to the test method specified in GB / T 1033.1.

[0067] According to the test method specified in GB / T 1845.1, the melt index (MI) of the matrix resin was tested at 190°C / 2.16kg.

[0068] According to GB / T2410-2008, the light transmittance of the matrix resin is tested within the wavelength range of 290nm to 1100nm.

[0069] According to GB / T1040.1-2006, the tensile properties of the matrix resin were tested at a tensile speed of 100 mm / min.

[0070] The volume resistivity of the matrix resin was tested according to GB / T1410-2006 at a voltage of 1000 V and a power-on time of 60 minutes.

[0071] Table 1 Comparison of properties of polyethylene elastomer (base resin) in Examples 1-3 and polyolefin elastomer in Comparative Examples 1-2

[0072]

[0073] Compared with the comparative example, the polyethylene elastomer of the present invention has little difference in terms of transmittance, density, melt index, molecular weight distribution and volume resistivity. The melting point is slightly lower than that of POE, but the difference is not large, which is more conducive to processing; the polyethylene elastomer composition of the present invention has higher tensile strength, elongation at break and degree of branching, which is conducive to providing better mechanical support for the components. The synthesis of commercially available polyolefin elastomers is carried out by random copolymerization of ethylene and α-olefins. The polyethylene elastomer in this application is obtained by chain-walking polymerization of ethylene monomer in the presence of a late transition metal complex catalyst, i.e., a nickel-based catalyst in this application, and a co-catalyst. It does not require the participation of expensive α-olefins, which greatly reduces costs. The photovoltaic film processed from polyethylene elastomer has a higher cost-performance ratio than commercially available polyolefin elastomers.

[0074] The polyethylene elastomer photovoltaic films and POE photovoltaic films obtained in Examples 1 to 3 and Comparative Examples 1 to 2 were subjected to crosslinking degree test, light transmittance test, peel strength test and volume resistivity test, respectively.

[0075] Among them, the method of cross-linking degree testing is:

[0076] The crosslinking degree of photovoltaic film was tested according to the xylene method in GB / T 29848-2018.

[0077] Among them, the method for light transmittance testing is:

[0078] According to GB / T2410-2008, transmittance of laminated photovoltaic film samples was tested within the wavelength range of 290nm to 1100nm. The lamination process was performed at a temperature of 145°C, vacuuming for 390s, and lamination time of 530s. The lamination equipment used was a Changzhou Shunhong Solar Module Laminator SH1000.

[0079] Among them, the test methods for tensile strength and elongation at break are:

[0080] According to GB / T1040.1-2006, the laminated photovoltaic film was subjected to a tensile test at a tensile speed of 100 mm / min.

[0081] Among them, the method of peel strength test is:

[0082] According to GB / T2790-1995, the laminated photovoltaic film sample was bonded to glass and subjected to a 180° peel strength test at a pulling speed of 100 mm / min.

[0083] Among them, the method for volume resistivity testing is:

[0084] The volume resistivity of the laminated photovoltaic film was tested according to GB / T1410-2006 at a voltage of 1000V and a power-on time of 60s.

[0085] The test results are shown in Table 2 below.

[0086] Table 2 Performance data of photovoltaic films prepared in Examples 1 to 3 and Comparative Examples 1 to 2

[0087]

[0088]

[0089] The test results in Table 2 show that, compared with conventional POE photovoltaic films, the photovoltaic film prepared from the polyethylene elastomer composition of the present invention maintains good light transmittance, with the transmittance at 290-380 nm and 380-1100 nm meeting the requirements of the National Energy Administration's POE encapsulation film industry standard NB / T 10200-2019; it has higher tensile strength and elongation at break, that is, better mechanical properties, and can provide better mechanical support for photovoltaic modules; while having higher fluidity, it also has higher peel strength, which can significantly improve the adhesion between the film and the battery module glass; it has comparable volume resistivity and water vapor permeability, and can have comparable anti-PID performance.

[0090] The photovoltaic films prepared in Example 1 and Comparative Example 1 were stacked with the same Topcon cells and tempered glass in the order of glass, film, cell, film, and glass, and then laminated using the same equipment and process into the following: Figure 1 The small double-glass photovoltaic module shown, Figure 1 The left figure represents Example 1 and the right figure represents Comparative Example 1. The EL test was conducted on the components. There were no obvious defects or black spots on the surface of both components. According to the IEC 60904-3 standard, under standard test conditions (STC: 1000W / m 2 IV characteristics testing was conducted under irradiance (100 nm, AM 1.5 spectrum, and a cell temperature of 25°C). The maximum power of the two modules was 4.34W and 4.42W, respectively, indicating that their electrical performance is basically equivalent.

[0091] The above is an exemplary description of the embodiments of the present invention. However, the scope of protection of the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A polyethylene elastomer composition for photovoltaic film, characterized in that: The polyethylene elastomer composition comprises, by weight, 100 parts of a base resin, 0.3 to 3 parts of a primary cross-linking agent, 0.3 to 3 parts of an auxiliary cross-linking agent, 0.05 to 3 parts of a silane coupling agent, 0.05 to 0.5 parts of an antioxidant, and 0.1 to 0.3 parts of a light stabilizer; wherein the base resin is selected from a polyethylene elastomer, and the raw materials for preparing the polyethylene elastomer do not contain α-olefins.

2. The composition according to claim 1, characterized in that The matrix resin is a polyethylene elastomer; the polyethylene elastomer is obtained by catalytic polymerization of ethylene monomer in the presence of a nickel catalyst and a co-catalyst.

3. The composition according to claim 2, characterized in that The nickel-based catalyst includes at least one of an α-diimine nickel complex catalyst, a pyridocycloheptaneimine nickel complex catalyst, and an α-diimine nickel complex catalyst modified with a fluorobenzhydryl group; Preferably, the cocatalyst comprises one or more of methylaluminoxane, triisobutylaluminum-modified methylaluminoxane, diethylaluminum chloride, dimethylaluminum chloride, sesquiethylaluminum chloride, and ethylaluminum dichloride. Preferably, the catalytic polymerization reaction is carried out in the presence of an organic solvent, and the organic solvent is selected from one or more of n-hexane, cyclohexane, toluene, o-xylene, dichloromethane, ethanol, tetrahydrofuran, n-heptane, and cycloheptane.

4. The composition according to claim 1, characterized in that The branching degree of the matrix resin is 70 to 150B / 1000C; Preferably, the weight average molecular weight of the matrix resin is 1×10 4 ~100×10 4 g·mol -1 , molecular weight distribution is between 1.7 and 2.5; Preferably, according to the test method specified in GB / T 1033.1, the density of the matrix resin is 0.850 g / cm 3 ~0.900g / cm 3 ; Preferably, according to the test method specified in GB / T 1845.1, at 190°C / 2.16kg, the melt index (MI) of the matrix resin is 14g / 10min-20g / 10min; Preferably, the melting point of the matrix resin is 50°C-90°C, preferably 50-80°C; Preferably, the glass transition temperature (Tg) of the matrix resin is -45°C to -60°C; Preferably, the tensile strength of the matrix resin is 8-15 MPa; Preferably, the elongation at break of the matrix resin is 1200-1600%.

5. The composition according to claim 1, characterized in that The main cross-linking agent is a mixture of one or more of tert-butyl peroxyisopropyl carbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-butyl peroxy-2-ethylhexyl carbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-amyl peroxycarbonate, tert-butyl peroxy-3,3,5-trimethylhexanoate and 1,3-bis-(2-tert-butylperoxyisopropyl).

6. The composition according to claim 1, characterized in that The auxiliary cross-linking agent is a mixture of one or more of triallyl isocyanate (such as triallyl isocyanurate), trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, trimethallyl isocyanate, trimethylolpropane trimethacrylate, and pentaerythritol triacrylate; Preferably, the silane coupling agent is a mixture of one or more of γ-methacryloxypropylmethyltrimethoxysilane, γ-glycidylpropyltrimethoxysilane, 3-aminopropyltriethoxysilane, tristearoyl isopropyl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, and vinyl-tris(2-methoxyethoxy) silane.

7. The composition according to claim 1, characterized in that The antioxidant is a mixture of one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris[2,4-di-tert-butylphenyl]phosphite and N,N'-1,6-hexanediylbis(3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionyl); Preferably, the light stabilizer is at least one of bis-2,2,6,6-tetramethylpiperidinol sebacate, 2,2,6,6-tetramethyl-4-piperidinyl ester, tetramethylpiperidone, and 1,5,8,12-tetrakis[4,6-bis(N-butyl-N-1,2,2,6,6-pentamethyl-4-piperidinylamino)-1,3,5-triazine-2-yl]-1,5,8,12-tetraazadodecane.

8. The method for preparing the composition according to any one of claims 1 to 7, characterized in that: The preparation method comprises: (1) mixing a main cross-linking agent, an auxiliary cross-linking agent, an antioxidant, a light stabilizer, and a silane coupling agent in proportion to obtain an auxiliary agent solution; (2) The additive solution is dispersed in the matrix resin, and the obtained mixture is subjected to a casting process to prepare a polyethylene elastomer composition.

9. The method according to claim 8, characterized in that In step (1), the mixing temperature is 70-90° C. and the mixing time is 0.5-4 h; The casting temperature is 90-120°C.

10. Use of the composition according to any one of claims 1 to 7 in the field of photovoltaic encapsulation, preferably, the polyethylene elastomer composition is used as a photovoltaic film. Preferably, a photovoltaic film, the raw material of which is the polyethylene elastomer composition according to any one of claims 1-7. Preferably, the photovoltaic adhesive film is a cast film of the polyethylene elastomer composition. Preferably, the photovoltaic adhesive film has a single-layer structure. Preferably, the photovoltaic film is used in photovoltaic modules. Preferably, the photovoltaic adhesive film is used as a packaging material in a photovoltaic module.

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