Polyolefin elastomer and use thereof in photovoltaic encapsulation film

Abstract

Provided in the present invention are a method for preparing a polyolefin elastomer and a composition thereof for use in a photovoltaic encapsulation film, and the use of the polyolefin elastomer and the composition. The polyolefin elastomer is a random or block polymer composed of ethylene and α-olefin, wherein the molecular weight Mw of the polyolefin elastomer is 30,000-200,000; the PDI thereof is 1.5-3; the MFR thereof measured under the conditions of a temperature of 190ºC and a load of 2.16 kg is 1-50 g / 10 min; the density thereof is 0.85-0.95 g / cm3; the monomer insertion rate is 10-65 wt%; and during heating and leaching processes of TGIC using trichlorobenzene, the content of soluble substances in a polyolefin resin at 40ºC or lower is 0.1% to 20%. The composition prepared from the elastomer has better optical performance, electrical insulation performance and anti-PID performance when being applied to a photovoltaic encapsulation adhesive film.

Description

A polyolefin elastomer and its application in photovoltaic encapsulation film Technical Field

[0001] The invention relates to a polyolefin elastomer for photovoltaic packaging films, belonging to the technical field of photovoltaic adhesive films. Background Art

[0002] Solar power generation devices utilize solar photovoltaic (PV) cell modules to convert light energy into electrical energy through the action of a PN junction. The most important core component is the PV module. This module is a sandwich device with a solar cell at the center, flanked by a PV film, and flanked by PV glass or a backsheet. The modules are laminated together through heating. Because PV modules have an operational lifespan of up to 25 years, the encapsulating film is extremely important. Failure of the film renders the module useless, shortening its operational lifespan.

[0003] Currently, crystalline silicon PERC cells remain the mainstream photovoltaic cell market, but the long-term reliable and stable operation of PERC modules faces a serious challenge: the PID effect (potential induced degradation). PID can reduce the output power of solar modules by 20%, and in severe cases, by more than 50%.

[0004] The real cause of the PID effect is still inconclusive, but the anti-PID performance of the film is still the most concerned issue in the industry. The common method in the industry to improve the anti-PID performance of the film is to add metal ion scavengers or ion conductors to the photovoltaic film. This method can achieve better anti-PID performance by adjusting the film formula, but it is still a temporary solution and not a fundamental solution.

[0005] Summary of the Invention

[0006] The present invention prepares POE particles with a special microstructure. By adjusting the microscopic soluble matter content of the particles, the optical and electrical properties of the particles are optimized, especially the PID performance is optimized, and the preparation of a photovoltaic composition with high transmittance and high anti-PID performance is achieved.

[0007] The technical solutions adopted in the present invention are as follows:

[0008] In one aspect, the present invention provides a polyolefin elastomer for photovoltaic encapsulation film, wherein the polyolefin elastomer is a random or block polymer composed of ethylene and α-olefin, and during the TGIC trichlorobenzene heating elution process, the soluble matter content below 40°C is 0.1%-20wt%; for example, 0.2wt%, 0.5wt%, 1wt%, 2wt%, 5wt%, 10wt%, 15wt%; further 0.1%-15wt%.

[0009] Furthermore, its molecular weight Mw is 30,000 to 200,000 (for example, 40,000, 50,000, 80,000, 100,000, 150,000), PDI is 1.5 to 3 (for example, 1.8, 2.0, 2.2, 2.5, 2.8), MFR measured under the conditions of 190°C and 2.16 kg load is 1 to 50 g / 10 minutes (for example, 2 g / 10 minutes, 4 g / 10 minutes, 5 g / 10 minutes, 8 g / 10 minutes, 10 g / 10 minutes, 15 g / 10 minutes, 20 g / 10 minutes, 25 g / 10 minutes, 30 g / 10 minutes, 40 g / 10 minutes), and density is 0.85 to 0.95 g / cm 3 (0.86g / cm 3 , 0.88g / cm 3 , 0.9g / cm 3 , 0.92g / cm 3 、0.94g / cm 3 ), further 0.85 to 0.90 g / cm 3 , the monomer insertion rate is 10 to 65 wt% (for example, 12 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 60 wt%), and further 20 to 65 wt%.

[0010] Furthermore, the volume resistivity of the polyolefin elastomer is 10 13 -10 18 Ω·cm, for example, 2*10 13 Ω·cm、5*10 13 Ω·cm, 10 14 Ω·cm、5*10 14 Ω·cm, 10 15 Ω·cm、5*10 15 Ω·cm, 10 16 Ω·cm、5*10 16 Ω·cm, 10 17 Ω·cm、5*10 17 Ω·cm;

[0011] Furthermore, in the polyolefin elastomer, the α-olefin is an olefin having 3 to 13 carbon atoms, preferably one or more of propylene, butene, hexene, octene, nonene and decene.

[0012] Furthermore, for example, the structural formula of a polyolefin elastomer can be expressed as:

[0013] Wherein, n is any integer from 0 to 10, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9.

[0014] The values ​​of x, y, and m can be selected conventionally in the art.

[0015] In a second aspect, the present invention provides a method for preparing the above-mentioned polyolefin elastomer.

[0016] Furthermore, the method for preparing the polyolefin elastomer for photovoltaic encapsulation film comprises the following steps:

[0017] Using a cationic coordination polymerization method, a solvent and an α-olefin are mixed in a certain proportion and then injected into a reactor. Ethylene gas is introduced at a temperature of 120-160° C. (for example, 130° C., 140° C., 150° C.) and a pressure of 1-5 MPa (for example, 2 MPa, 3 MPa, 4 MPa). The main catalyst and the co-catalyst are then added to the reactor and stirred for reaction for 3-15 minutes (for example, 4 minutes, 5 minutes, 8 minutes, 10 minutes, 12 minutes) to obtain a reactant solution.

[0018] The inactivator is added to the system and reacted fully to obtain a product, which is then cooled and dried to obtain a polymer.

[0019] In the preparation method, the solvent is selected from aliphatic hydrocarbon solvents and / or aromatic hydrocarbon solvents; preferably, the aliphatic hydrocarbon solvent is selected from one or more of n-butane, isobutane, n-pentane, cyclopentane, methylcyclopentane, methylenecyclopentane, n-hexane, cyclohexane, methylcyclohexane, ethylcyclohexane, n-heptane, n-octane, n-nonane or Isopar E; the aromatic hydrocarbon solvent is preferably selected from one or more of benzene, toluene, xylene, monochlorobenzene, dichlorobenzene and dichlorotoluene;

[0020] The α-olefin is an olefin having 3 to 13 carbon atoms, preferably one or more of propylene, butene, hexene, octene, nonene and decene;

[0021] The main catalyst is a metallocene catalyst and / or a post-metallocene catalyst, preferably dimethylsilyl (N-tert-butylamino) (tetramethylcyclopentadienyl) titanium dichloride, dimethylsilyl (N-tert-butylamino) (tetramethylcyclopentadienyl) titanium dimethyl, dimethylsilyl (N-tert-butylamino) (fluorenyl) titanium dichloride, (pentamethylcyclopentadienyl) trimethoxytitanium, dibenzylidene (cyclopentadiene) (9-fluorenyl) zirconium dichloride, dimethyldisilylbis (2-methyl-4-phenyl-1-indenyl) zirconium dichloride), mesodimethylsilylbis (1-indenyl) zirconium dichloride, (bis (methylcyclopentadiene) zirconium dichloride), (bis (1,3-dimethylcyclopentadienyl) zirconium dichloride, (cyclopentadienyl) (1,2-dimethoxyethane) zirconium trichloride, diphenylsilyl One or more of alkyl (cyclopentadienyl) (9-fluorenyl) zirconium dichloride, racemic dimethylsilyl bis (2-methyl-1-indenyl) zirconium dichloride, dibenzylidenecyclopentadienyl (2,7-di-tert-butyl-fluorenyl) zirconium dichloride, di-p-toluenedicyclopentadienyl (2,7-di-tert-butyl-fluorenyl) zirconium dichloride, dimethylbis (propylcyclopentadienyl) hafnium, bis (n-butylcyclopentadienyl) hafnium dichloride, and dimethylsilyl bis (2-methyl-4-phenylindenyl) zirconium dichloride; the amount of the main catalyst added can be confirmed by those skilled in the art based on the catalyst activity and the weight of the target product. Generally, the amount of the main catalyst added can be 1-10 ppm (for example, 2 ppm, 4 ppm, 5 ppm, 8 ppm) based on the weight of the polymer;

[0022] The cocatalyst is at least one of an alkyl aluminum, an organic boron compound, and an alkyl aluminoxane, preferably one or more of methyl aluminoxane, modified methyl aluminoxane, ethyl aluminoxane, trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, and tris(pentafluorophenyl) boron; the amount of the cocatalyst added is 200-9800 ppm (e.g., 250 ppm, 500 ppm, 1000 ppm, 2000 ppm, 5000 ppm, 8000 ppm, 9000 ppm) based on the weight of the polymer;

[0023] The inactivator is a mixture of inactivator A and inactivator B, and the mixing mass ratio of the two is 1-5:1-5 (for example, 1:1, 1:2, 1:3, 1:4, 1:5, 2:1, 2:3, 2:5, 3:1, 3:2, 3:4, 3:5, 4:1, 4:3, 4:5, 5:1, 5:2, 5:3, 5:4), wherein inactivator A It is water and / or an alcohol with 2 to 20 carbon atoms, and the alcohol is preferably ethanol, ethylene glycol, n-propanol, glycerol, n-butanol, 2-butanol, neopentyl alcohol, 1,6-hexanediol, n-octanol, 2-ethylhexanol, benzyl alcohol, n-decanol, dodecanol, tetradecanol, and hexadecanol; the inactivator B is a ketone, and is preferably one or more of dimethyl ketone, diethyl ketone, butanone, methyl isobutyl ketone, valerophenone, ethyl octanone, methyl n-nonanone, methyl hexanone, dipyrrolidone, bicyclo[3.3.1]nonane-3,7-dione, dimethylcyclohexanedione, 2,2,6-trimethyl-1,4-cyclohexanedione, diphenylethanedione, 3-methyl-2,4-nonanedione, 1-phenyl-2,4-pentanedione, and 2,4-decanedione. The amount of the inactivating agent used is 600-150,000 ppm (e.g., 800 ppm, 1,000 ppm, 2,000 ppm, 5,000 ppm, 10,000 ppm, 50,000 ppm, 100,000 ppm, 120,000 ppm) based on the weight of the polymer.

[0024] In yet another aspect, the present invention provides use of the polyolefin elastomer in preparing a photovoltaic encapsulation film.

[0025] Furthermore, the photovoltaic encapsulation film comprises the polyolefin elastomer, a cross-linking agent, a co-cross-linking agent, a coupling agent, and an antioxidant as described above;

[0026] In a specific embodiment, the dosage of each component is:

[0027] Polyolefin elastomer: 100 parts by weight,

[0028] Cross-linking agent: 0.1-5 parts by weight (e.g., 0.2 parts by weight, 0.4 parts by weight, 1 part by weight, 1.5 parts by weight, 2.5 parts by weight, 4 parts by weight, 4.5 parts by weight), preferably 0.5-2 parts by weight

[0029] Cross-linking agent: 0.1-5 parts by weight (e.g., 0.2 parts by weight, 0.4 parts by weight, 1 part by weight, 1.5 parts by weight, 2.5 parts by weight, 4 parts by weight, 4.5 parts by weight), preferably 0.1-2 parts by weight

[0030] Coupling agent: 0.1-3 parts by weight (e.g., 0.2 parts by weight, 0.4 parts by weight, 0.5 parts by weight, 1 part by weight, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight), preferably 0.1-0.6 parts by weight

[0031] Antioxidant: 0.01-1 part by weight (e.g., 0.02 part by weight, 0.04 part by weight, 0.06 part by weight, 0.1 part by weight, 0.2 part by weight, 0.4 part by weight, 0.8 part by weight), preferably 0.05-0.5 part by weight;

[0032] Further, the cross-linking agent is a peroxide cross-linking agent, including but not limited to one or more of the following: tert-butyl peroxy isopropyl carbonate, 2,5-dimethyl-2,5-(bis-tert-butylperoxy)hexane, tert-butyl peroxy-2-ethylhexyl carbonate, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-butyl peroxy-2-ethylhexyl carbonate, tert-amyl peroxy (2-ethylhexyl) carbonate, tert-butyl peroxy-3,3,5-trimethylhexanoate;

[0033] Furthermore, the auxiliary cross-linking agent is one or more of multifunctional acrylate substances, including but not limited to: trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, triallyl isocyanurate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, trimethylolpropane tetraacrylate, ditrimethylolpropane tetraacrylate, ditrimethylolpropane tetramethacrylate, propoxylated pentaerythritol tetraacrylate, tricyclopentane dimethanol diacrylate, propoxylated neopentyl glycol diacrylate, ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, 2-butyl-2-ethyl-1,3-propanediol diacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate;

[0034] Furthermore, the coupling agent is a silane coupling agent, including but not limited to one or more of the following: γ-chloropropylmethoxysilane, dimethylvinylethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloyloxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidyloxypropyltrimethoxysilane, 3-(trimethoxysilyl)propyl-2-methyl-2-acrylate, anilinemethyltriethoxysilane, octyltrimethoxysilane;

[0035] Furthermore, the antioxidant is one or more of hindered phenols or phosphate antioxidants, including but not limited to: β-[3,5-di-tert-butyl-4-hydroxyphenyl] propionate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,2-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine, 2,2'-oxalylamino-bis[ethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)] propionate, N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, tert-Butyl-4-hydroxyphenylpropionamide), 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)trione, triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], 4,6-bis(octylthiomethyl)-o-cresol, tris[2,4-di-tert-butylphenyl]phosphite, bis[2,4-di-tert-butylphenyl]pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate.

[0036] Furthermore, the photovoltaic encapsulation film can be prepared using conventional methods in the art, for example, including the following steps: high-temperature premixing of raw materials, melt extrusion, film casting, cooling, slitting, and winding processes.

[0037] The beneficial effects of the present invention are:

[0038] The present invention can obtain a low content of soluble matter below 40°C (less than 20%), ensuring that the low molecular weight portion of the matrix resin is small. On the one hand, POE particles with high PID resistance can be obtained without upgrading the film formula, which can fundamentally improve the PID resistance of the photovoltaic film. On the other hand, the resin has higher optical properties and electrical insulation properties. DETAILED DESCRIPTION

[0039] The present invention will be further described below through specific examples. The examples of the present invention are only for illustration of the present invention and do not limit the scope of the present invention.

[0040] In the present application, "parts" and "%" are by weight unless otherwise specified.

[0041] Main materials:

[0042] Ethylene-octene copolymer A (MFR: 2 g / 10 min (190 ° C, 2.16 kg), Mw is 57000, PDI is 2.8, density is 0.87 g / cm 3 , octene content 40wt%, soluble matter below 40°C content 1wt%, homemade);

[0043] Ethylene-octene copolymer B (MFR: 5 g / 10 min (190 ° C, 2.16 kg), Mw is 70000, PDI is 2.3, density is 0.868 g / cm 3 , soluble matter content below 40°C 3wt%, octene content 33wt%, homemade);

[0044] Ethylene-butene copolymer C (MFR: 5 g / 10 min (190 ° C, 2.16 kg), Mw is 75000, PDI is 2.2, density is 0.877 g / cm 3 , soluble matter content below 40°C 5wt%, butene content 24wt%, homemade);

[0045] Ethylene-hexene copolymer D (MFR: 25 g / 10 min (190 ° C, 2.16 kg), Mw is 40000, PDI is 2, density is 0.875 g / cm 3 , hexene content 30wt%, soluble matter below 40°C content 7wt%, homemade);

[0046] Ethylene-octene copolymer E (MFR: 35 g / 10 min (190 ° C, 2.16 kg), Mw is 100000, PDI is 2.5, density is 0.873 g / cm 3 , octene content 30wt%, soluble matter below 40°C content 15%, homemade);

[0047] Ethylene-hexene copolymer F (MFR: 3 g / 10 min (190 ° C, 2.16 kg), Mw is 13000, PDI is 2.1, density is 0.872 g / cm 3 , hexene content 35wt%, soluble matter content below 40℃ 38%, homemade);

[0048] Methylaluminoxane, AkzoNobel, 10% toluene solution;

[0049] Modified methylaluminoxane, Nouryon;

[0050] Dimethylsilylbis(2-methyl-4-phenylindenyl)zirconium dichloride, Yaodexin Chemical;

[0051] Di-p-toluene methylene cyclopentadiene (2,7-di-tert-butyl-fluorenyl) zirconium dichloride, Yanfeng Technology, dimethylsilyl (N-tert-butylamino) (tetramethylcyclopentadienyl) titanium dimethyl, Jiangsu Xinnoko Catalyst Co., Ltd., dimethylbis (propylcyclopentadienyl) hafnium, Yanfeng Technology, dibenzylidene cyclopentadiene (2,7-di-tert-butyl-fluorenyl) zirconium dichloride, Yaodexin Chemical,

[0052] Dimethylsilyl (tert-butylamino) tetramethylcyclopentadienyl titanium dimethyl, Sinoco.

[0053] Test equipment:

[0054] Melt index tester: ZwickMflow, test standard ASTM D1238.

[0055] The extruder was a single-screw extruder (L / D=35) with a screw diameter of 30 mm.

[0056] Molecular weight and insertion rate tester: Polymer Char, GPC-IR.

[0057] Soluble Matter Analysis: Polymer Char, TGIC, Solvent Trichlorobenzene. TGIC uses a ramped elution method to separate and characterize different polyolefin components. The sample is dissolved in trichlorobenzene at 165°C and passed through the TGIC column. The temperature is then programmed to 40°C (20°C / min). Some polyolefin structures adhere to the column due to adsorption and crystallization on the graphite column. The column is flushed at a flow rate of 0.5 ml / min, and the soluble fraction is flushed to the IR5 detector for detection. The elution is then ramped up at a rate of 2°C / min to 165°C. Molecules attached to the column are sequentially eluted based on their crystallization ability and the number of short chain branches.

[0058] PID equipment: Shanghai Zhiwei environmental chamber model EW-EC03PID02-021220.

[0059] Power test equipment: Nanjing Lixit model LXT-CELL.

[0060] Ohmmeter: Keithley model 6517B, 1000V, 10min.

[0061] Preparation example:

[0062] Preparation of Ethylene-Octene Copolymer A: Using cationic metallocene coordination polymerization, 200 g of octene was added to 1 L of n-butane solvent to form a solution, which was then added to a reactor. The temperature was raised to 150°C, and ethylene gas was introduced, maintaining the reactor pressure at 2.5 MPa. 1 mg of the main catalyst, dimethylsilylbis(2-methyl-4-phenylindenyl)zirconium dichloride, and 5 mL of a 10 wt% methylaluminoxane toluene solution as the cocatalyst were added to the reactor, stirred, and reacted for 15 minutes to obtain a reactant solution.

[0063] Water and 3-methyl-2,4-nonanedione were mixed in a mass ratio of 3:1. After the total mass of 1.2 g of the mixture was fully reacted with the reactant solution, the obtained product was cooled, filtered and dried to obtain ethylene-octene copolymer A. MFR: 2 g / 10 min (190 ° C, 2.16 kg), Mw: 57000, PDI: 2.8, density: 0.87 g / cm 3, octene content 40wt%, soluble matter below 40℃ content 1wt%, volume resistivity 10 17 Ω·cm.

[0064] Preparation of Ethylene-Octene Copolymer B: Using a cationic metallocene coordination polymerization method, 190 g of octene was added to 1 L of Isopar E to form a solution, which was then added to a reactor. The temperature was raised to 150°C, and ethylene gas was introduced, maintaining the reactor pressure at 2.5 MPa. The main catalyst, 0.87 mg of di-p-tolylmethylcyclopentadiene (2,7-di-tert-butylfluorenyl) zirconium dichloride, and the co-catalyst, 7 ml of a 10 wt% methylaluminoxane solution in toluene, were added to the reactor, stirred, and reacted for 15 minutes to obtain a reactant solution.

[0065] Water and 3-methyl-2,4-nonanedione were mixed in a mass ratio of 4:1. The total mass of the mixture (900 mg) was mixed with the reactant solution and allowed to react fully. The obtained product was cooled to obtain a solid precipitate, which was filtered and dried to obtain ethylene-octene copolymer B. MFR: 5 g / 10 min (190°C, 2.16 kg), Mw: 70,000, PDI: 2.3, and density: 0.868 g / cm 3 , soluble matter content below 40℃ is 3wt%, octene content is 33wt%, volume resistivity is 10 17 Ω·cm.

[0066] Preparation of Ethylene-Butene Copolymer C: Using a cationic metallocene coordination polymerization method, 1 L of Isopar E was added to a reactor, the temperature was raised to 140°C, and gas was introduced at a ratio of 1:1 ethylene:butene. The reactor pressure was maintained at 3 MPa. 0.8 mg of the main catalyst, dimethylsilyl(N-tert-butylamino)(tetramethylcyclopentadienyl)titanium dimethyl, and 8 mL of a 7% Al Isopar E-modified methylaluminoxane solution were added to the reactor, stirred, and reacted for 15 minutes to obtain a reactant solution.

[0067] Water and dipyrrolidone were mixed in a mass ratio of 1:2, and the mixture (600 mg) was fully reacted with the reactant solution. The obtained product was cooled, filtered, and dried to obtain ethylene-butene copolymer C. MFR: 5 g / 10 min (190°C, 2.16 kg), Mw: 75,000, PDI: 2.2, and density: 0.877 g / cm 3 , soluble matter content below 40℃ is 5wt%, butene content is 24wt%, volume resistivity is 10 16 Ω·cm.

[0068] Preparation of Ethylene-Hexene Copolymer D: 200 g of hexene was added to 1 L of Isopar E solvent to form a solution, which was then added to a reactor. The temperature was raised to 140°C, and ethylene gas was introduced, maintaining the reactor pressure at 2.8 MPa. 0.9 mg of the main catalyst, dimethylbis(propylcyclopentadienyl)hafnium, and 3 mL of a 10 wt% methylaluminoxane toluene solution as the cocatalyst were added to the reactor, stirred, and reacted for 15 minutes to obtain a reactant solution.

[0069] After mixing n-butanol and 1-phenyl-2,4-pentanedione in a mass ratio of 2:3, the total mass of the mixture (400 mg) was fully reacted with the reactant solution. The obtained product was cooled, filtered and dried to obtain ethylene-hexene copolymer D. MFR: 25 g / 10 min (190 ° C, 2.16 kg), Mw: 40000, PDI: 2, density: 0.875 g / cm 3 , hexene content 30wt%, soluble matter below 40℃ content 7wt%, volume resistivity 10 15 Ω·cm.

[0070] Preparation of Ethylene-Octene Copolymer E: Using a cationic metallocene coordination polymerization method, 190 g of octene was added to 1 L of Isopar E solvent to form a solution, which was then added to a reactor. The temperature was raised to 150°C, and ethylene gas was introduced, maintaining the reactor pressure at 3.5 MPa. The main catalyst, dibenzylidenecyclopentadienyl (2,7-di-tert-butylfluorenyl) zirconium dichloride, 1 mg, and the cocatalyst, 10 ml of a 7% Al Isopar E-modified methylaluminoxane solution, were added to the reactor, stirred, and reacted for 15 minutes to obtain a reactant solution.

[0071] After mixing ethanol and ethyl octanone in a mass ratio of 3:5, the total mass of the mixture (200 mg) was fully reacted with the reactant solution. The obtained product was cooled, filtered and dried to obtain ethylene-octene copolymer E. MFR: 35 g / 10 min (190 ° C, 2.16 kg), Mw: 100000, PDI: 2.5, density: 0.873 g / cm 3 , octene content 30wt%, soluble matter below 40℃ content 15%, volume resistivity 10 15 Ω·cm.

[0072] Preparation of Ethylene-Hexene Copolymer F: Using cationic metallocene coordination polymerization, 160 g of octene was added to 1 L of n-butane solvent to form a solution, which was then added to a reactor. The temperature was raised to 135°C, and ethylene gas was introduced, maintaining the reactor pressure at 2.5 MPa. 1 mg of the main catalyst, dimethylsilyl (tert-butylamino) tetramethylcyclopentadienyl titanium dimethyl, and 4 ml of a 10 wt% methylaluminoxane toluene solution were added to the reactor, stirred, and reacted for 15 minutes to obtain a reactant solution.

[0073] After 100 mg of water was fully reacted with the reaction solution, the obtained product was cooled, filtered and dried to obtain ethylene-hexene copolymer F. MFR: 3 g / 10 min (190°C, 2.16 kg), Mw: 13000, PDI: 2.1, density: 0.872 g / cm 3 , hexene content 35wt%, soluble matter below 40℃ 38%, volume resistivity 10 14 Ω·cm.

[0074] Examples and Comparative Examples:

[0075] Example 1:

[0076] To 1000g of ethylene-octene copolymer A, 9g of tert-butyl peroxide 2-ethylhexyl carbonate, 5g of triallyl isocyanurate, 2g of γ-methacryloyloxypropyl trimethoxysilane, 1g of γ-(2,3-epoxypropoxy)propyl trimethoxysilane, 1g of bis[2,4-di-tert-butylphenyl]pentaerythritol diphosphite, and 1g of β-[3,5-di-tert-butyl-4-hydroxyphenyl]propionic acid n-octadecyl ester were added. The above raw materials were heated to 50°C and mixed evenly. The extruder parameters were adjusted to the temperature from the feed port to the die head of 80°C, 90°C, 90°C, 90°C, 90°C, 95°C, 95°C, 95°C, the screw speed was 45rpm, the pulling speed was 0.7rpm, and the winding speed was 1.3rpm. After extrusion, film casting, cooling, slitting, and winding, an encapsulation film for photovoltaic modules was prepared with a film thickness of 0.6mm.

[0077] Example 2

[0078] To 1000g of ethylene-octene copolymer B were added 6g of 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 2g of tert-amyl peroxy(2-ethylhexyl)carbonate, 4g of trimethylolpropane triacrylate, 2g of γ-methacryloxypropyltrimethoxysilane, 1g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 0.1g of antioxidant 1076, and 1g of antioxidant 1010. The above raw materials were heated to 50°C and mixed uniformly. The extruder parameters were adjusted to the temperature from the feed port to the die head of 80°C, 90°C, 90°C, 90°C, 90°C, 95°C, 95°C, 95°C, the screw speed was 45rpm, the pulling speed was 0.7rpm, and the winding speed was 1.3rpm. After extrusion, film casting, cooling, slitting, and winding, an encapsulation film for photovoltaic modules was prepared with a film thickness of 0.6mm.

[0079] Example 3

[0080] To 1000g of ethylene-butene copolymer C, 20g of tert-butyl peroxy-2-ethylhexyl carbonate, 7g of triallyl isocyanurate, 8g of dimethylvinylethoxysilane, and 0.5g of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] were added. The above raw materials were heated to 50°C and mixed uniformly. The extruder parameters were adjusted to the temperature from the feed port to the die head of 80°C, 90°C, 90°C, 90°C, 90°C, 95°C, 95°C, 95°C, the screw speed was 45rpm, the pulling speed was 0.7rpm, and the winding speed was 1.3rpm. After extrusion, film casting, cooling, slitting, and winding, an encapsulation film for photovoltaic modules was prepared. The film thickness was 0.6mm.

[0081] Example 4

[0082] To 1000 g of ethylene-hexene copolymer D, 15 g of 2,2-bis(tert-butylperoxy)butane, 10 g of triallyl isocyanurate, 15 g of γ-methacryloyloxypropyltrimethoxysilane, 0.1 g of 1,2-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine and 1 g of triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate] were added. The raw materials were heated to 50° C. and mixed uniformly. The extruder parameters were adjusted to the temperature from the feed port to the die head of 80° C., 90° C., 90° C., 90° C., 95° C., 95° C., 95° C., the screw speed was 45 rpm, the pulling speed was 0.7 rpm, and the winding speed was 1.3 rpm. After extrusion, film casting, cooling, slitting and winding, an encapsulation film for photovoltaic modules was prepared. The film thickness was 0.6 mm.

[0083] Example 5

[0084] To 1000g of ethylene-octene copolymer E, 10g of tert-butyl peroxy-2-ethylhexyl carbonate, 8g of triallyl isocyanurate, 2g of octyltrimethoxysilane, 1g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 0.1g of triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], and 1g of bis[2,4-di-tert-butylphenyl]pentaerythritol diphosphite were added. The raw materials were heated to 50°C and mixed uniformly. The extruder parameters were adjusted to the temperature from the feed port to the die head of 80°C, 90°C, 90°C, 90°C, 90°C, 95°C, 95°C, 95°C, the screw speed was 45rpm, the pulling speed was 0.7rpm, and the winding speed was 1.3rpm. After extrusion, film casting, cooling, slitting, and winding, an encapsulation film for photovoltaic modules was prepared with a film thickness of 0.6mm.

[0085] Comparative Example 1

[0086] To 1000g of ethylene-hexene copolymer F, 9g of tert-butyl peroxide 2-ethylhexyl carbonate, 5g of triallyl isocyanurate, 2g of γ-methacryloyloxypropyl trimethoxysilane, 1g of γ-(2,3-epoxypropoxy)propyl trimethoxysilane, 1g of bis[2,4-di-tert-butylphenyl]pentaerythritol diphosphite, and 1g of β-[3,5-di-tert-butyl-4-hydroxyphenyl]propionic acid n-octadecyl ester were added. The above raw materials were heated to 50°C and mixed evenly. The extruder parameters were adjusted to the temperature from the feed port to the die head of 80°C, 90°C, 90°C, 90°C, 90°C, 95°C, 95°C, 95°C, the screw speed was 45rpm, the pulling speed was 0.7rpm, and the winding speed was 1.3rpm. After extrusion, film casting, cooling, slitting, and winding, an encapsulation film for photovoltaic modules was prepared with a film thickness of 0.6mm.

[0087] The encapsulation films prepared in the above examples and comparative examples were used to prepare photovoltaic modules, and their light transmittance and PID performance were tested. The test results are shown in the table below.

[0088] Among them, the test method is:

[0089] PID Attenuation: The films prepared in each Example and Comparative Example were used as the front and back encapsulation films for the same photovoltaic module, which consisted of tempered glass, an upper encapsulation film, bifacial crystalline silicon solar cells, a lower encapsulation film, and tempered glass. The modules were placed in a laminator at 150°C, first under vacuum and then under pressure, for crosslinking for 18 minutes. The power changes of the modules were measured before and after HAST aging (85°C, 85% RH, 1500V, 192h).

[0090] Light transmittance test: Tested according to the spectrophotometer method of GB / T 2410-2008, and the average light transmittance in the wavelength range of 290nm-380nm and 380nm-1100nm was calculated respectively.

[0091] Example and comparative example test results:

[0092] From the comparison of the performance test data of the embodiment and the comparative example described in the above table, it can be seen that:

[0093] The present invention provides a polyolefin elastomer and composition thereof for photovoltaic encapsulation films. The soluble matter content of the base resin is controlled during the synthesis process to improve the PID resistance of the base resin itself. The resulting photovoltaic film can achieve high PID resistance without adding anti-PID additives at the formulation level. This can be widely promoted in the film field, reducing the addition of additives, and also has excellent optical properties.

[0094] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. A polyolefin elastomer, characterized in that: The polyolefin elastomer is a random or block polymer composed of ethylene and α-olefin; the α-olefin of the polyolefin elastomer is an olefin having 3 to 13 carbon atoms; The polyolefin elastomer has a soluble matter content of 0.1% to 15wt% below 40°C during the TGIC trichlorobenzene heating and elution process; The polyolefin elastomer has a molecular weight Mw of 30,000 to 200,000, a PDI of 1.5 to 3, an MFR of 1 to 50 g / 10 minutes at 190° C. and a load of 2.16 kg, and a density of 0.85 to 0.90 g / cm 3 , the monomer insertion rate is 20 to 65 wt%.

2. The polyolefin elastomer according to claim 1, characterized in that The volume resistance of the polyolefin elastomer is 10 13 -10 18 Ω·cm.

3. The polyolefin elastomer according to claim 1 or 2, characterized in that: The α-olefin is selected from one or more of propylene, butene, hexene, octene, nonene and decene.

4. A method for preparing a polyolefin elastomer according to any one of claims 1 to 3, comprising the following steps: The solvent and α-olefin are mixed and injected into a reactor, ethylene gas is introduced at a certain temperature, and then the main catalyst and the co-catalyst are added into the reactor and stirred for reaction to obtain a reactant solution; Add the inactivator into the system and obtain the product after sufficient reaction; The inactivator is a mixture of inactivator A and inactivator B, and the mixing ratio of the two is 1-5:1-5; in, The inactivator A is water and / or an alcohol having 2 to 20 carbon atoms; and the inactivator B is a ketone.

5. The preparation method according to claim 4, characterized in that: The main catalyst is a metallocene catalyst and / or a post-metallocene catalyst.

6. The preparation method according to claim 5, characterized in that: The main catalyst is selected from dimethylsilyl (N-tert-butylamino) (tetramethylcyclopentadienyl) titanium dichloride, dimethylsilyl (N-tert-butylamino) (tetramethylcyclopentadienyl) dimethyl titanium, dimethylsilyl (N-tert-butylamino) (fluorenyl) titanium dichloride, (pentamethylcyclopentadienyl) trimethoxytitanium, dibenzylidene (cyclopentadiene) (9-fluorenyl) zirconium dichloride, mesodimethylsilyl bis (1-indenyl) zirconium dichloride, bis (methylcyclopentadiene) zirconium dichloride, bis (1,3-dimethylcyclopentadienyl) zirconium dichloride, (cyclopentadienyl) One or more of (1,2-dimethoxyethane) zirconium trichloride, diphenylsilyl (cyclopentadiene) (9-fluorenyl) zirconium dichloride, racemic dimethylsilyl bis (2-methyl-1-indenyl) zirconium dichloride, diphenylmethylenecyclopentadiene (2,7-di-tert-butyl-fluorenyl) zirconium dichloride, di-p-toluenemethylenecyclopentadiene (2,7-di-tert-butyl-fluorenyl) zirconium dichloride, dimethylbis (propylcyclopentadienyl) hafnium, bis (n-butylcyclopentadiene) hafnium dichloride, dimethylsilylbis (2-methyl-4-phenylindenyl) zirconium dichloride.

7. The preparation method according to any one of claims 4 to 6, characterized in that: The co-catalyst is at least one of alkyl aluminum, organic boron compound and alkyl aluminoxane.

8. The preparation method according to claim 7, characterized in that: The co-catalyst is selected from one or more of methylaluminoxane, modified methylaluminoxane, ethylaluminoxane, trimethylaluminum, triethylaluminum, triisobutylaluminum, and tris(pentafluorophenyl)boron.

9. The preparation method according to any one of claims 4 to 8, characterized in that: The inactivator A is selected from one or more of ethanol, ethylene glycol, n-propanol, glycerol, n-butanol, 2-butanol, neopentyl alcohol, 1,6-hexanediol, n-octanol, 2-ethylhexanol, benzyl alcohol, n-decanol, dodecanol, tetradecanol, and hexadecanol; The inactivator B is selected from one or more of dimethyl ketone, diethyl ketone, butanone, methyl isobutyl ketone, valerophenyl ketone, ethyl octanone, methyl nonanone, methyl hexanophenyl ketone, dipyrrolidone, bicyclo[3.3.1]nonane-3,7-dione, dimethylcyclohexanedione, 2,2,6-trimethyl-1,4-cyclohexanedione, diphenylethanedione, 3-methyl-2,4-nonanedione, 1-phenyl-2,4-pentanedione, and 2,4-decanedione.

10. Use of the polyolefin elastomer according to any one of claims 1 to 3 or the polyolefin elastomer prepared by the preparation method according to any one of claims 4 to 9 in preparing photovoltaic encapsulation films.

11. A photovoltaic encapsulation film, comprising: the polyolefin elastomer according to any one of claims 1 to 3 or the polyolefin elastomer prepared by the preparation method according to any one of claims 4 to 9, a cross-linking agent, a co-cross-linking agent, a coupling agent, and an antioxidant.

12. The photovoltaic encapsulation film according to claim 11, characterized in that: The dosage of each component of the photovoltaic encapsulation film is: Polyolefin elastomer: 100 parts by weight, Cross-linking agent: 0.1-5 parts by weight, Cross-linking agent: 0.1-5 parts by weight, Coupling agent: 0.1-3 parts by weight, Antioxidant: 0.01-1 parts by weight.

13. The photovoltaic encapsulation film according to claim 11 or 12, characterized in that: The cross-linking agent is a peroxide cross-linking agent; and / or: The auxiliary cross-linking agent is one or more of multifunctional acrylate substances; and / or: The coupling agent is a silane coupling agent; and / or: The antioxidant is one or more of hindered phenol or phosphate antioxidants.

14. The photovoltaic encapsulation film according to claim 13, characterized in that: The cross-linking agent is selected from one or more of the following: tert-butyl peroxy isopropyl carbonate, 2,5-dimethyl-2,5-(bis-tert-butylperoxy)hexane, tert-butyl peroxy carbonate-2-ethylhexyl ester, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-butyl peroxy 2-ethylhexyl carbonate, tert-amyl peroxy (2-ethylhexyl) carbonate, tert-butyl peroxy 3,3,5-trimethylhexanoate; and / or: The auxiliary crosslinking agent is selected from one or more of the following: trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, triallyl isocyanurate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, trimethylolpropane tetraacrylate, Ditrimethylolpropane tetraacrylate, ditrimethylolpropane tetramethacrylate, propoxylated pentaerythritol tetraacrylate, tricyclohexane dimethanol diacrylate, propoxylated neopentyl glycol diacrylate, ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, 2-butyl-2-ethyl-1,3-propanediol diacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate; and / or: The coupling agent is selected from one or more of the following: γ-chloropropylmethoxysilane, dimethylvinylethoxysilane, vinyltri(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidyloxypropyltrimethoxysilane, 3-(trimethoxysilyl)propyl-2-methyl-2-acrylate, anilinemethyltriethoxysilane, octyltrimethoxysilane; and / or: The antioxidant is selected from one or more of the following: β-[3,5-di-tert-butyl-4-hydroxyphenyl] propionate octadecyl alcohol ester, tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester, 1,2-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine, 2,2'-oxalyl-bis[ethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)] propionate, N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyphenylpropionamide )、1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)trione, triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], 4,6-bis(octylthiomethyl)-o-cresol, tris[2,4-di-tert-butylphenyl]phosphite, bis[2,4-di-tert-butylphenyl]pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate.

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