A polyolefin photovoltaic adhesive film, a preparation method thereof, and uses thereof

Abstract

The present invention provides a polyolefin photovoltaic adhesive film, a preparation method and uses thereof. The polyolefin photovoltaic adhesive film uses a polyolefin elastomer POE, as well as certain proportions of modified resin, silane oligomer, silane end-capping agent, additives and other components, enabling the various components to cooperate synergistically, thereby obtaining a polyolefin adhesive film with improved anti-slip and anti-aging properties. When applied to the battery module end, it does not slip, the air exhaust of the adhesive film is smooth during lamination, and it is not easy to generate bubbles. The peel strength retention rate with the glass plate and the battery chip is high under high temperature and high humidity, and ultraviolet aging environments.

Description

Technical Field

[0001] The present invention relates to the field of encapsulation materials for photovoltaic cells, and particularly to a polyolefin photovoltaic adhesive film, a preparation method thereof, and uses thereof. Background Art

[0002] Due to its narrow molecular weight distribution, short branched-chain structure, and saturated structure, polyolefin elastomer POE has excellent physical and mechanical properties such as high elasticity, high strength, and high elongation rate, as well as excellent characteristics such as heat aging resistance, ultraviolet resistance, low water vapor permeability, and anti-PID (potential induced degradation). Currently, it has been widely used as an encapsulation adhesive film for photovoltaic cells.

[0003] In photovoltaic encapsulation adhesive films, auxiliary materials such as crosslinking agents, coupling agents, antioxidants, and ultraviolet absorbers are usually added to achieve firm encapsulation protection of photovoltaic cell wafers and long-term outdoor weather resistance. However, due to the non-polar characteristics of POE, the compatibility between the auxiliary components in the adhesive film and the POE chain segment molecules is poor, resulting in easy precipitation of the auxiliaries in the POE adhesive film, affecting the crosslinking speed during lamination of the adhesive film with the cell wafer and the crosslinking degree after lamination, and showing poor phenomena such as peeling strength attenuation and delamination from the cell wafer during the later aging process. In addition, the auxiliaries will also migrate to the surface of the adhesive film, causing the friction coefficient of the film surface to become smaller, resulting in problems such as slippage when fitting with the cell wafer and cell wafer splicing.

[0004] Currently, the conventional solution is to co-extrude ethylene-vinyl acetate copolymer EVA and polyolefin elastomer POE to form an EPE adhesive film, that is, a sandwich structure with a POE middle layer and EVA on both sides. However, due to factors such as the inconsistent modulus and tensile stress of EVA and POE, and the easy migration of the auxiliaries in the POE layer to the EVA layer, problems such as delamination between EVA and POE and the formation of bubbles during lamination occur.

[0005] CN112063337A discloses an anti-mechanical impact photovoltaic adhesive film and a preparation method thereof. The anti-mechanical impact photovoltaic adhesive film is made of 0.1% - 45% of an elastomer resin system, 20 - 95% of a hot-melt thermosetting resin system, and 0.1% - 5% of glass fiber as basic materials; the elastomer resin system is made of 95 - 99% of an elastomer resin, 0.05% - 5% of an antioxidant, 0.25% - 5% of a free radical crosslinking agent, and 0.1% - 4% of a silane coupling agent. The photovoltaic adhesive film uses the hot-melt thermosetting resin and its curing system to provide anti-mechanical impact for the photovoltaic adhesive film; uses glass fiber to provide anti-mechanical impact for the photovoltaic adhesive film; uses an elastomer to provide toughness for the adhesive film to prevent fragmentation during processing, transportation, storage, and use. And, after hot pressing, the photovoltaic adhesive film can provide mechanical strength for the component, effectively resist mechanical impact, and at the same time prevent the fragmentation problem of the photovoltaic adhesive film during production, storage, transportation, use, etc. However, the problems of auxiliary precipitation and slipping are not solved.

[0006] CN115287003A discloses a composite hot-melt adhesive film for metal bonding, which is characterized by comprising the following raw materials in parts by weight: 80-100 parts of resin; 12-20 parts of maleic anhydride graft; 1-3 parts of initiator; 3-15 parts of first tackifier; 0.3-1.5 parts of second tackifier; 0.1-1 part of antioxidant; 0.1-1 part of ultraviolet absorber; the melt flow rate of the resin is 35-40 g / 10min / 190°C / 2.16 kg. Its preparation process is simple, and it bonds firmly with metal, solving the problem of poor metal bonding force; the materials used to prepare the hot-melt adhesive film are green and environmentally friendly, and no odor or toxic substances will be generated during the processing, and there is no solvent volatilization, which is conducive to the technological innovation of materials; the hot-melt adhesive film fits evenly and has good bonding strength with metal. However, the problems of additive precipitation and slipping have not been solved.

[0007] In addition, many manufacturers will start from the surface structure of the POE film. As described in CN 213534113 U, matte patterns with embossed structures of different shapes and depths are set on both sides of the adhesive layer to increase the friction force of the contact surface to solve the slipping phenomenon at the battery module end. However, this process still cannot completely avoid the slipping problem caused by the migration of additives to the surface.

[0008] Therefore, it is an urgent problem to be solved to develop a polyolefin photovoltaic film to improve its surface viscoelasticity, promote the compatibility between additives and POE, and at the same time improve the heat resistance and weather resistance. Summary of the Invention

[0009] Aiming at the deficiencies of the prior art, the present invention provides a polyolefin photovoltaic film. The polyolefin photovoltaic film adopts two polyolefin elastomers POE with different melt indices and octene contents, as well as certain proportions of modified resin, silane oligomer and silane end-capping agent, additives and other components, so that each component cooperates synergistically, thereby obtaining a polyolefin film with improved anti-slip and anti-aging properties, which does not slip when applied to the battery module end, the film exhausts smoothly during lamination, is not easy to produce bubbles, and has a high peel strength retention rate with the glass plate and the battery chip under high temperature and high humidity, ultraviolet aging environments.

[0010] The technical solution of the present invention is as follows:

[0011] A polyolefin photovoltaic film, comprising the following components:

[0012] Polyolefin elastomer, modified resin, silane oligomer coupling agent, silane end-capping agent and additives;

[0013] Among them, the modified resin contains thermoplastic elastomer, and the thermoplastic elastomer is selected from one or more of SBS, SEBS, SEPS, POE, POP, EAA, EVA, TPU, TPV;

[0014] The silane oligomer coupling agent is selected from at least two of vinyl silanes, amino silanes, and methacryloxy silanes;

[0015] The silane end-capping agent is an aminopropyl silane or a mercaptopropyl silane;

[0016] The surface friction coefficient of the polyolefin photovoltaic film is ≥0.5;

[0017] The polyolefin photovoltaic film needs to undergo vacuum lamination during use. After vacuum lamination, the peel strength between the polyolefin photovoltaic film and the embossed glass is ≥120 N / cm, and after aging for 1000 h in an 85°C high-temperature and 85% high-humidity environment, the peel strength is ≥80 N / cm, 120 kWh / m 2 The peel strength after UV aging is ≥80 N / cm, the light transmittance is ≥90.5%, and the crosslinking degree is ≥75%.

[0018] Furthermore, the polyolefin photovoltaic film comprises the following components in parts by weight: 100 parts by weight of the polyolefin elastomer, 5 - 30 parts by weight of the modified resin, 0.1 - 3 parts by weight of the silane oligomer coupling agent, 0.1 - 3 parts by weight of the silane end-capping agent, and 0.35 - 14 parts by weight of the auxiliary agent.

[0019] Furthermore, the polyolefin elastomer comprises any one or two of polyolefin elastomer POE A and polyolefin elastomer POE B. Preferably, the polyolefin elastomer is composed of polyolefin elastomer POE A and polyolefin elastomer POE B. The melt index of the polyolefin elastomer POE A is between 2 - 10 g / 10 min, and the octene content is 30 - 40%. The melt index of the polyolefin elastomer POE B is between 8 - 20 g / 10 min, and the octene content is 20 - 30%.

[0020] Furthermore, the modified resin is composed of a thermoplastic elastomer and a tackifying resin.

[0021] Furthermore, the tackifying resin in the modified resin is one or more of rosin resin, terpene resin, petroleum resin, and alkylphenol formaldehyde resin.

[0022] Furthermore, in the modified resin, the mass fraction of the thermoplastic elastomer is 60 - 90 parts, and the mass fraction of the tackifying resin is 10 - 40 parts.

[0023] Furthermore, the thermoplastic elastomer is a mixture of SEBS and EVA, and the weight ratio is between 1 - 4 to 6 - 9.

[0024] Further, the silane oligomer coupling agent is at least two of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(β-methoxyethoxy)silane, vinyltri-tert-butoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, methacryloyloxy oligomer, γ-methacryloyloxypropyltrimethoxysilane, etc.

[0025] Further, the silane end-capping agent is one or more of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-n-butyl-3-aminopropyltrimethoxysilane, or N-phenyl-3-aminopropyltrimethoxysilane.

[0026] Further, the additives include one or more of peroxide crosslinking agents, co-crosslinking agents, antioxidants, light stabilizers, and ultraviolet absorbers.

[0027] Further, based on the mass of the polyolefin photovoltaic film, the weight parts of the peroxide crosslinking agent are 0.1 - 3 parts, the weight parts of the co-crosslinking agent are 0.1 - 5 parts, the weight parts of the antioxidant are 0.05 - 2 parts, the weight parts of the light stabilizer are 0.05 - 2 parts, and the weight parts of the ultraviolet absorber are 0.05 - 2 parts.

[0028] Further, the peroxide crosslinking agent is one or more of tert-butyl peroxy-2-ethylhexyl carbonate, tert-amyl peroxy(2-ethylhexyl) carbonate, tert-butyl peroxybenzoate, tert-butyl peroxyacetate, tert-amyl peroxy-2-ethylhexanoate, tert-butyl peroxy-2-ethylhexanoate, dicumyl peroxide, etc.

[0029] Further, the co-crosslinking agent is one or more of triallyl cyanurate, trimethylolpropane trimethacrylate, triallyl isocyanurate, ethoxylated pentaerythritol tetraacrylate, 3(ethoxy)trimethylolpropane triacrylate, dipropylene glycol diacrylate, propoxylated neopentyl glycol diacrylate, pentaerythritol triacrylate, etc. Further, the antioxidant includes a main antioxidant and a co-antioxidant, and the weight ratio is 2:1; the main antioxidant is octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; the co-antioxidant is tris(4-nonylphenyl) phosphite and / or tris(2,4-di-tert-butylphenyl) phosphite.

[0030] Further, the light stabilizer is one or more of cyanuric chloride polymer, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, polybutanedioic acid (4-hydroxy-2,2,6,6-tetramethyl-1-piperidylethanol) ester, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole, 2,4-dichloro-6-(4-morpholinyl)-1,3,5-triazine, 2,2,6,6-tetramethyl-4-piperidyl stearate.

[0031] Further, the ultraviolet absorber is one or more of 2-hydroxy-4-n-octyloxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-5-methylphenyl) benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl) benzotriazole, 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-octyloxyphenol, n-hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate.

[0032] Further, the vacuum lamination conditions are as follows: the lamination temperature is 142 - 155 °C, the vacuum pumping time is 5 - 10 minutes, and the lamination time is 12 - 18 minutes.

[0033] Further, the structure of the polyolefin photovoltaic film prepared from the above materials includes, but is not limited to, single-layer POE, two-layer or multi-layer POE, POE / EVA, EVA / POE / EVA, POE / TPO, POE / POP, etc.

[0034] The present invention also provides a method for preparing the foregoing polyolefin photovoltaic film, and the method includes the following steps:

[0035] Step 1: Put the polyolefin elastomer and the modified resin into a mixer according to the ratio and physically mix and stir for 10 - 30 min;

[0036] Step 2: Add a peroxide crosslinking agent to the above resin mixture and stir for 30 - 60 min;

[0037] Step 3: Disperse the co-crosslinking agent, silane oligomer coupling agent, silane end-capping agent, antioxidant, light stabilizer, and ultraviolet absorber with a high-speed disperser for 30 - 60 min;

[0038] Step 4: Add the uniformly mixed additives in Step 3 to the resin mixture in Step 2, and continue to stir for 6 - 12 h until the additives are completely absorbed;

[0039] Step 5: Feed the fully absorbed material in Step 4 into a screw extruder or calender through a feeding system, and cast and extrude or calender it into a film at 80-120 °C.

[0040] In the method, in Step 3, in the cross-linking reaction, the peroxide cross-linking agent decomposes at high temperature to provide free radicals, and the free radicals initiate cross-linking reactions such as chain growth. The reaction formula is shown in Formula (I):

[0041]

[0042] The silane oligomer coupling agent undergoes a melt grafting reaction with polyolefin under this reaction, as shown in the following reaction formula (II):

[0043]

[0044] Further, the method further includes Step 6, feeding the formed polyolefin photovoltaic film in Step 5 into the space between a rubber roller and an embossing roller through traction for pressing to form patterns.

[0045] Further, the method further includes Step 7, slitting and winding the polyolefin photovoltaic film obtained in Step 6 after cooling and shaping, and packaging it into a finished product as required.

[0046] Further, the thickness of the polyolefin photovoltaic film is 0.1-1 mm, and the grammage is 100-800 g / m 2 .

[0047] The present invention also provides a use of the aforementioned polyolefin photovoltaic film for encapsulating photovoltaic cells.

[0048] The present invention has the following beneficial effects:

[0049] 1. In the polyolefin photovoltaic film formulation of the present invention, a modified resin is introduced, which improves the physical adhesion of the polyolefin elastomer POE matrix, and prevents problems such as film slippage and cell parallel connection during lamination with the cell.

[0050] 2. The present invention applies resin modification technology. By adding a modified resin, on the one hand, the physical adhesion of the polyolefin elastomer POE matrix is improved. This is because components such as SEBS and EVA in the modified resin increase the viscoelasticity of the photovoltaic film system, thereby enhancing its anti-slip performance; on the other hand, the polar groups in EVA and the tackifying resin promote the compatibility of the auxiliary monomers (peroxide cross-linking agent, silane capping agent, co-cross-linking agent, etc.) with the polyolefin elastomer POE, providing sites for the entanglement and cross-linking of molecular chains, enabling the auxiliary agents to react fully, reducing the possibility of auxiliary agent precipitation, and thus improving the slippage problem caused by auxiliary agent precipitation.

[0051] 3. The silane oligomer coupling agent contains functional groups for stepwise condensation reaction and double bonds that can potentially undergo addition polymerization reaction, enabling the silane capping agent to be effectively bonded to the macromolecular chain segments and preventing precipitation. The silane capping agent acts similar to a co-crosslinking agent, which can prevent the continuation of chain growth, achieve crosslinking faster, improve the crosslinking speed and degree of the polymer, and enhance the heat resistance and weather resistance.

[0052] 4. The formulation of the polyolefin photovoltaic film can be applied to structures including but not limited to single-layer POE, two-layer or multi-layer POE, POE / EVA, EVA / POE / EVA, POE / TPO, POE / POP, etc., to solve the problems of slippage, laminating, and non-aging resistance corresponding to single-layer or composite films. Detailed implementation manners

[0053] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0054] Example 1

[0055] A photovoltaic film, based on the mass of the polyolefin photovoltaic film, contains the following components in parts by mass:

[0056] 30 parts of polyolefin elastomer POEA with an MI content of 5 g / 10 min;

[0057] 70 parts of polyolefin elastomer POEB with an MI content of 18 g / 10 min;

[0058] 10 parts of modified resin, wherein the thermoplastic elastomer is SEBS and EVA, accounting for 80% of the total mass of the modified resin, and the mass ratio of SEBS:EVA is 4:6; the terpene resin is used as the tackifying resin, accounting for 20% of the total mass of the modified resin;

[0059] 1.2 parts of the peroxide crosslinking agent is 2-ethylhexyl peroxycarbonate;

[0060] 0.8 parts of the co-crosslinking agent is triallyl cyanurate;

[0061] 0.4 parts of the silane oligomer coupling agent is vinyltris(β-methoxyethoxy)silane and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane,

[0062] wherein, the mass ratio of vinyltris(β-methoxyethoxy)silane and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane is 1:2;

[0063] The silane end-capping agent is 3-aminopropyltriethoxysilane, 0.5 parts;

[0064] The antioxidant is 0.4 parts. The main antioxidant is octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; the co-antioxidant is tris(4-nonylphenyl) phosphite, and the mass ratio of the main antioxidant to the co-antioxidant is 2:1;

[0065] The light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, 0.4 parts;

[0066] The ultraviolet absorber is 2-hydroxy-4-n-octyloxybenzophenone, 0.3 parts;

[0067] When the polyolefin photovoltaic film is used, it needs to go through a vacuum lamination operation. After vacuum lamination, the peel strength between the polyolefin photovoltaic film and the embossed glass is 190 N / cm. After aging for 1000 h in an 85 °C high-temperature and 85% high-humidity environment, the peel strength is 121 N / cm, 120 kWh / m 2 After ultraviolet aging, the peel strength is 115 N / cm, the light transmittance is 90.5%, and the crosslinking degree is 86%.

[0068] The preparation method is as follows:

[0069] Step 1: Put the polyolefin elastomer and the modified resin into a mixer according to the ratio and physically mix and stir for 10 - 30 min;

[0070] Step 2: Add the peroxide crosslinking agent to the above resin mixture and stir for 30 - 60 min;

[0071] Step 3: Disperse the co-crosslinking agent, silane oligomer coupling agent, silane end-capping agent, antioxidant, light stabilizer, and ultraviolet absorber with a high-speed disperser for 30 - 60 min;

[0072] Step 4: Add the uniformly mixed additives in Step 3 to the resin mixture described in Step 2, and continue to stir for 6 - 12 h until the additives are completely absorbed;

[0073] Step 5: Feed the fully absorbed material in Step 4 into a screw extruder or a calender through a feeding system, and cast and extrude or calender into a film at 80 - 120 °C.

[0074] Example 2

[0075] A photovoltaic film, based on the mass of the polyolefin photovoltaic film, contains the following components in parts by mass:

[0076] The polyolefin elastomer POEA is 30 parts, and its MI content is 5 g / 10 min;

[0077] 70 parts of polyolefin elastomer POEB with an MI content of 18 g / 10 min;

[0078] 10 parts of modified resin, in which the thermoplastic elastomer is SEBS and EVA, accounting for 80%, and the mass ratio of SEBS:EVA is 6:4; the terpene resin is used as the tackifying resin, accounting for 20%.

[0079] The peroxide crosslinking agent is tert-butyl peroxy-2-ethylhexyl carbonate, 1.2 parts;

[0080] The co-crosslinking agent is triallyl cyanurate, 0.8 parts;

[0081] The silane oligomer coupling agent is N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane 0.4 parts,

[0082] Among them, the mass ratio of vinyltris(β-methoxyethoxy)silane and γ-methacryloxypropyltrimethoxysilane is 1:2;

[0083] The silane end-capping agent is 3-aminopropyltriethoxysilane, 0.5 parts;

[0084] 0.4 parts of antioxidant, the main antioxidant is octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; the co-antioxidant is tris(4-nonylphenyl) phosphite, and the mass ratio of the main antioxidant to the co-antioxidant is 2:1;

[0085] The light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, 0.4 parts;

[0086] The ultraviolet absorber is 2-hydroxy-4-n-octyloxybenzophenone, 0.3 parts;

[0087] The polyolefin photovoltaic film needs to be subjected to vacuum lamination during use. After vacuum lamination, the peel strength between the polyolefin photovoltaic film and the embossed glass is 184 N / cm, and the peel strength after aging in an 85°C high-temperature and 85% high-humidity environment is 108 N / cm, 120 kWh / m 2 The peel strength after ultraviolet aging is 129 N / cm, the light transmittance is 90.5%, and the crosslinking degree is 82%.

[0088] The preparation method is as follows:

[0089] Step 1: Put the polyolefin elastomer and the modified resin into a mixer according to the ratio and mix and stir physically for 10-30 min;

[0090] Step 2: Add the peroxide crosslinking agent to the above resin mixture and stir for 30-60 min;

[0091] Step 3: Disperse the co-crosslinking agent, silane oligomer coupling agent, silane end-capping agent, antioxidant, light stabilizer, and ultraviolet absorber with a high-speed disperser for 30 - 60 min;

[0092] Step 4: Add the uniformly mixed additives in Step 3 to the resin mixture in Step 2, and continue stirring for 6 - 12 h until the additives are completely absorbed;

[0093] Step 5: Feed the completely absorbed material in Step 4 into a screw extruder or calender through a feeding system, and cast and extrude or calender it into a film at 80 - 120 °C.

[0094] Example 3

[0095] A photovoltaic adhesive film, based on the mass of the polyolefin photovoltaic adhesive film, contains the following components in parts by mass:

[0096] 30 parts of polyolefin elastomer POEA with an MI content of 5 g / 10 min;

[0097] 70 parts of polyolefin elastomer POEB with an MI content of 18 g / 10 min;

[0098] 10 parts of modified resin, where the thermoplastic elastomer is SEBS and EVA, accounting for 80% and the ratio of SEBS:EVA is 4:6; the tackifying resin is terpene resin, accounting for 20%;

[0099] 1.2 parts of peroxide crosslinking agent, tert-butyl peroxy-2-ethylhexyl carbonate;

[0100] 0.8 part of co-crosslinking agent, triallyl cyanurate;

[0101] 0.4 part of silane oligomer coupling agent, vinyltris(β-methoxyethoxy)silane and γ-methacryloxypropyltrimethoxysilane,

[0102] where the mass ratio of vinyltris(β-methoxyethoxy)silane to γ-methacryloxypropyltrimethoxysilane is 1:2;

[0103] 0.5 part of silane end-capping agent, 3-aminopropyltriethoxysilane;

[0104] 0.4 part of antioxidant, the main antioxidant is octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; the co-antioxidant is tris(4-nonylphenyl) phosphite, and the mass ratio of the main antioxidant to the co-antioxidant is 2:1;

[0105] 0.4 part of light stabilizer, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate;

[0106] The ultraviolet absorber is 2-hydroxy-4-n-octyloxybenzophenone, 0.3 parts;

[0107] When the polyolefin photovoltaic film is used, it needs to go through a vacuum lamination operation. After vacuum lamination, the peel strength between the polyolefin photovoltaic film and the embossed glass is 225 N / cm. After aging in an 85°C high-temperature and 85% high-humidity environment, the peel strength is 160 N / cm, 120 kWh / m 2 After ultraviolet aging, the peel strength is 178 N / cm, the light transmittance is 91.6%, and the crosslinking degree is 88%.

[0108] The preparation method is as follows:

[0109] Step 1: Put the polyolefin elastomer and the modified resin into a mixer according to the ratio and physically mix and stir for 10 - 30 min;

[0110] Step 2: Add the peroxide crosslinking agent to the above resin mixture and stir for 30 - 60 min;

[0111] Step 3: Disperse the co-crosslinking agent, silane oligomer coupling agent, silane end-capping agent, antioxidant, light stabilizer, and ultraviolet absorber with a high-speed disperser for 30 - 60 min;

[0112] Step 4: Add the uniformly mixed additives in Step 3 to the resin mixture described in Step 2 and continue to stir for 6 - 12 h until the additives are completely absorbed;

[0113] Step 5: Feed the completely absorbed material in Step 4 into a screw extruder or calender through a feeding system, and cast and extrude or calender into a film at 80 - 120°C.

[0114] Example 4

[0115] A photovoltaic film, based on the mass of the polyolefin photovoltaic film, contains the following components in parts by mass:

[0116] 100 parts of polyolefin elastomer POEA, with an MI content of 5 g / 10 min;

[0117] 10 parts of modified resin, where the thermoplastic elastomer is SEBS and EVA, accounting for 80% and SEBS:EVA is 4:6; the terpene resin is used as the tackifying resin, accounting for 20%;

[0118] The peroxide crosslinking agent is tert-butyl peroxy-2-ethylhexyl carbonate, 1.2 parts;

[0119] The co-crosslinking agent is triallyl cyanurate, 0.8 parts;

[0120] The silane oligomer coupling agent is vinyltris(β-methoxyethoxy)silane and γ-methacryloxypropyltrimethoxysilane, 0.4 parts,

[0121] Among them, the mass ratio of vinyltris(β-methoxyethoxy)silane to γ-methacryloxypropyltrimethoxysilane is 1:2;

[0122] The silane end-capping agent is 3-aminopropyltriethoxysilane, 0.5 part;

[0123] The antioxidant is 0.4 part. The main antioxidant is octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; the co-antioxidant is tris(4-nonylphenyl) phosphite, and the mass ratio of the main antioxidant to the co-antioxidant is 2:1;

[0124] The light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, 0.4 part;

[0125] The ultraviolet absorber is 2-hydroxy-4-n-octyloxybenzophenone, 0.3 part;

[0126] When the polyolefin photovoltaic film is used, it needs to go through a vacuum lamination operation. After the vacuum lamination, the peel strength between the polyolefin photovoltaic film and the embossed glass is 176 N / cm, and the peel strength after aging in an 85°C high-temperature and 85% high-humidity environment is 109 N / cm, 120 kWh / m 2 The peel strength after ultraviolet aging is 156 N / cm, the light transmittance is 90.5%, and the crosslinking degree is 76%.

[0127] The preparation method is as follows:

[0128] Step 1: Put the polyolefin elastomer and the modified resin into a mixer according to the ratio and carry out physical mixing and stirring for 10 - 30 min;

[0129] Step 2: Add the peroxide crosslinking agent to the above resin mixture and stir for 30 - 60 min;

[0130] Step 3: Disperse the co-crosslinking agent, the silane oligomer coupling agent, the silane end-capping agent, the antioxidant, the light stabilizer, and the ultraviolet absorber with a high-speed disperser for 30 - 60 min;

[0131] Step 4: Add the additives uniformly mixed in Step 3 to the resin mixture described in Step 2, and continue stirring for 6 - 12 h until the additives are completely absorbed;

[0132] Step 5: Feed the completely absorbed material in Step 4 into a screw extruder or a calender through a feeding system, and cast and extrude or calender into a film at 80 - 120°C.

[0133] Example 5

[0134] A photovoltaic film, based on the mass of the polyolefin photovoltaic film, contains the following components in parts by mass:

[0135] 100 parts of polyolefin elastomer POE with an MI content of 5 g / 10 min;

[0136] 10 parts of modified resin, where the thermoplastic elastomer is SEBS and EVA, accounting for 80% and the ratio of SEBS:EVA is 4:6; the tackifying resin is terpene resin, accounting for 20%;

[0137] The peroxide crosslinking agent is 2-ethylhexyl peroxycarbonate, 1.2 parts;

[0138] The co-crosslinking agent is triallyl cyanurate, 0.8 parts;

[0139] The silane oligomer coupling agent is vinyltris(β-methoxyethoxy)silane and γ-methacryloxypropyltrimethoxysilane, 0.4 parts,

[0140] Among them, the mass ratio of vinyltris(β-methoxyethoxy)silane and γ-methacryloxypropyltrimethoxysilane is 1:2;

[0141] The silane end-capping agent is 3-aminopropyltriethoxysilane, 0.5 parts;

[0142] 0.4 parts of antioxidant, the main antioxidant is octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; the co-antioxidant is tris(4-nonylphenyl) phosphite, and the mass ratio of the main antioxidant to the co-antioxidant is 2:1;

[0143] The light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, 0.4 parts;

[0144] The ultraviolet absorber is 2-hydroxy-4-n-octyloxybenzophenone, 0.3 parts;

[0145] When the polyolefin photovoltaic film is used, it needs to go through a vacuum lamination operation. After vacuum lamination, the peel strength between the polyolefin photovoltaic film and the embossed glass is 206 N / cm, and the peel strength after aging in an 85°C high-temperature and 85% high-humidity environment is 96 N / cm, 120 kWh / m 2 The peel strength after ultraviolet aging is 174 N / cm, the light transmittance is 90.8%, and the crosslinking degree is 82%.

[0146] The preparation method is as follows:

[0147] Step 1: Put the polyolefin elastomer and the modified resin into a mixer according to the ratio and physically mix and stir for 10 - 30 min;

[0148] Step 2: Add the peroxide crosslinking agent to the above resin mixture and stir for 30 - 60 min;

[0149] Step 3: Disperse the co-crosslinking agent, silane oligomer coupling agent, silane end-capping agent, antioxidant, light stabilizer, and ultraviolet absorber with a high-speed disperser for 30 - 60 min;

[0150] Step 4: Add the auxiliaries uniformly mixed in Step 3 to the resin mixture described in Step 2, and continue stirring for 6 - 12 h until the auxiliaries are completely absorbed;

[0151] Step 5: Feed the material completely absorbed in Step 4 into a screw extruder or calender through a feeding system, and cast and extrude or calender it into a film at 80 - 120 °C.

[0152] Comparative Example 1

[0153] A photovoltaic film, based on the mass of the polyolefin photovoltaic film, contains the following components in parts by mass:

[0154] 30 parts of polyolefin elastomer POE A with an MI content of 5 g / 10 min;

[0155] 70 parts of polyolefin elastomer POEB with an MI content of 18 g / 10 min;

[0156] 1.2 parts of the peroxide crosslinking agent tert-butyl peroxy-2-ethylhexyl carbonate;

[0157] 0.8 part of the co-crosslinking agent triallyl cyanurate;

[0158] 0.4 part of the coupling agent vinyltris(β-methoxyethoxy)silane;

[0159] 0.5 part of the end-capping agent 3-aminopropyltriethoxysilane;

[0160] 0.4 part of antioxidant, the main antioxidant is octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; the auxiliary antioxidant is tris(4-nonylphenyl) phosphite, and the mass ratio of the main antioxidant to the auxiliary antioxidant is 2:1;

[0161] 0.4 part of the light stabilizer bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate;

[0162] 0.3 part of the ultraviolet absorber 2-hydroxy-4-n-octyloxybenzophenone.

[0163] The preparation process is as in Example 1.

[0164] Comparative Example 2

[0165] A photovoltaic film, based on the mass of the polyolefin photovoltaic film, contains the following components in parts by mass:

[0166] 30 parts of polyolefin elastomer POE A, with an MI content of 5 g / 10 min;

[0167] 70 parts of polyolefin elastomer POEB, with an MI content of 18 g / 10 min;

[0168] 10 parts of modified resin, in which the thermoplastic elastomer is SEBS and EVA, accounting for 80%, and the mass ratio of SEBS:EVA is 4:6; the tackifying resin is terpene resin, accounting for 20%;

[0169] The peroxide crosslinking agent is 2-ethylhexyl peroxycarbonate, 1.2 parts;

[0170] The co-crosslinking agent is triallyl cyanurate, 0.8 parts;

[0171] The coupling agent is vinyltris(β-methoxyethoxy)silane, 0.4 parts;

[0172] 0.4 parts of antioxidant, the main antioxidant is octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; the co-antioxidant is tris(4-nonylphenyl) phosphite, and the mass ratio of the main antioxidant to the co-antioxidant is 2:1;

[0173] The light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, 0.4 parts;

[0174] The ultraviolet absorber is 2-hydroxy-4-n-octyloxybenzophenone, 0.3 parts.

[0175] The preparation process is as in Example 1.

[0176] Comparative Example 3

[0177] A photovoltaic film, based on the mass of the polyolefin photovoltaic film, contains the following components in parts by mass:

[0178] 30 parts of polyolefin elastomer POE A, with an MI content of 5 g / 10 min;

[0179] 70 parts of polyolefin elastomer POEB, with an MI content of 18 g / 10 min;

[0180] The peroxide crosslinking agent is 2-ethylhexyl peroxycarbonate, 1.2 parts;

[0181] The co-crosslinking agent is triallyl cyanurate, 0.8 parts;

[0182] The coupling agent is vinyltris(β-methoxyethoxy)silane, 0.4 parts;

[0183] 0.4 parts of antioxidant, the main antioxidant is octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; the auxiliary antioxidant is tris(4-nonylphenyl)phosphite, and the mass ratio of the main antioxidant to the auxiliary antioxidant is 2:1;

[0184] The light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, 0.4 parts;

[0185] The ultraviolet absorber is 2-hydroxy-4-n-octyloxybenzophenone, 0.3 parts.

[0186] The preparation process is as in Example 1.

[0187] Test Example

[0188] Test the anti-slip performance of the polyolefin photovoltaic encapsulant films prepared in the test examples and comparative examples, such as the surface friction coefficient, and other characteristic indexes of the photovoltaic encapsulant film, such as light transmittance, crosslinking degree, peel strength, aging resistance, etc. The surface friction coefficient refers to the standard "GB10006-1988 Determination Method of Friction Coefficient of Plastic Films and Sheets", and other characteristic indexes refer to the standard "T / CPIA0006-2017 Copolyolefin Films for Photovoltaic Module Encapsulation".

[0189] Table 1 shows the test results of the friction coefficient, light transmittance, peel strength before and after aging, etc. of the polyolefin photovoltaic encapsulant films prepared in the examples and comparative examples after lamination with glass plates and backsheets.

[0190]

[0191] It can be seen from the comparison of Examples 1, 2, 3 with Comparative Examples 1, 2, 3 that for the encapsulant films added with modified resin, silane oligomer coupling agent and end-capping agent, the surface friction coefficient of the film has been significantly improved, and under the high-temperature and high-humidity aging conditions, the peel strength has a small attenuation.

[0192] It can be seen from Comparative Example 1 that for the encapsulant film without added modified resin, the surface friction coefficient is significantly reduced, and under high-temperature and high-humidity aging, the peel strength has a large attenuation.

[0193] It can be seen from Comparative Example 2 that for the encapsulant film without added silane end-capping agent, the surface friction coefficient is reduced, and under high-temperature and high-humidity aging, the peel strength has a large attenuation.

[0194] It can be seen from Comparative Example 3 that for the encapsulant film without added modified resin and silane end-capping agent, the surface friction coefficient is the smallest, and the peel strength decreases linearly under high-temperature and high-humidity and ultraviolet aging, and the attenuation is the fastest after aging.

[0195] In the modified resin of the present invention, SEBS and EVA increase the viscoelasticity of the system, improve the surface adhesion, and the polar groups in EVA and terpene resin promote the compatibility between the additives and the resin, preventing the additives from precipitating during the lamination process. The silane oligomer coupling agent and the silane end-capping agent can increase the crosslinking speed of the polymer, increase the crosslinking degree, and improve the heat resistance and weather resistance.

[0196] The above are only the preferred embodiments of the present invention, and do not limit the present invention in any other form. Any modification or equivalent change made according to the technical essence of the present invention still belongs to the scope protected by the present invention.

Claims

1. A polyolefin photovoltaic adhesive film, characterized in that, It comprises the following components: Polyolefin elastomer, modified resin, silane oligomer coupling agent, silane end-capping agent and additives; Among them, the modified resin is composed of a thermoplastic elastomer and a tackifying resin; the thermoplastic elastomer is a mixture of SEBS and EVA, and the weight ratio is between 1 - 4 to 6 - 9; the tackifying resin in the modified resin is one or more of rosin resin, terpene resin, petroleum resin, alkylphenol formaldehyde resin; in the modified resin, the mass fraction of the thermoplastic elastomer is 60 - 90 parts, and the mass fraction of the tackifying resin is 10 - 40 parts; The silane oligomer coupling agent is at least two of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, vinyltri-tert-butoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane; The silane end-capping agent is one or several of 3-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-n-butyl-3-aminopropyltrimethoxysilane or N-phenyl-3-aminopropyltrimethoxysilane; The surface friction coefficient of the polyolefin photovoltaic film is ≥0.5; The polyolefin photovoltaic film comprises the following components in parts by weight, 100 parts by weight of the polyolefin elastomer, 5 - 30 parts by weight of the modified resin, 0.1 - 3 parts by weight of the silane oligomer coupling agent, 0.1 - 3 parts by weight of the silane end-capping agent and 0.35 - 14 parts by weight of the additives; Among them, based on the mass of the polyolefin photovoltaic film, in the additives, the weight fraction of the peroxide cross-linking agent is 0.1 - 3 parts, the weight fraction of the co-crosslinking agent is 0.1 - 5 parts, the weight fraction of the antioxidant is 0.05 - 2 parts, the weight fraction of the light stabilizer is 0.05 - 2 parts, and the weight fraction of the ultraviolet absorber is 0.05 - 2 parts; The polyolefin photovoltaic adhesive film needs to undergo vacuum lamination during use. After vacuum lamination, the peel strength between the polyolefin photovoltaic adhesive film and the embossed glass is ≥120 N / cm, and the peel strength is ≥80 N / cm after aging for 1000 h in an environment of 85°C high temperature and 85% high humidity, 120 kWh / m 2 The peel strength after UV aging is ≥80 N / cm, the light transmittance is ≥90.5%, and the crosslinking degree is ≥75%.

2. The polyolefin photovoltaic adhesive film according to claim 1, characterized in that, The polyolefin elastomer comprises any one or two of polyolefin elastomer POE A and polyolefin elastomer POE B. The melt index of the polyolefin elastomer POE A is between 2 - 10 g / 10 min, and the octene content is 30 - 40%. The melt index of the polyolefin elastomer POE B is between 18 - 20 g / 10 min, and the octene content is 20 - 30%.

3. The polyolefin photovoltaic adhesive film according to claim 2, wherein, The peroxide cross-linking agent is one or more of tert-butyl peroxy-2-ethylhexyl carbonate, tert-amyl peroxy(2-ethylhexyl) carbonate, tert-butyl peroxybenzoate, tert-butyl peroxyacetate, tert-amyl peroxy-2-ethylhexanoate, tert-butyl peroxy-2-ethylhexanoate, dicumyl peroxide; 4. The polyolefin photovoltaic adhesive film according to claim 2, wherein The co-crosslinking agent is one or more of triallyl cyanurate, trimethylolpropane trimethacrylate, triallyl isocyanurate, ethoxylated pentaerythritol tetraacrylate, 3(ethoxy)trimethylolpropane triacrylate, dipropylene glycol diacrylate, propoxylated neopentyl glycol diacrylate, pentaerythritol triacrylate; 5. The polyolefin photovoltaic adhesive film according to claim 2, wherein, The antioxidant includes a primary antioxidant and a secondary antioxidant, and the weight ratio is 2:1; the primary antioxidant is octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate; the secondary antioxidant is tris(4-nonylphenyl) phosphite and / or tris(2,4-di-tert-butylphenyl) phosphite.

6. The polyolefin photovoltaic adhesive film according to claim 2, wherein The light stabilizer is one or more of bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, polybutanedioic acid (4-hydroxy-2,2,6,6-tetramethyl-1-piperidylethanol) ester, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 2,2,6,6-tetramethyl-4-piperidyl stearate.

7. The polyolefin photovoltaic adhesive film according to claim 2, wherein The ultraviolet absorber is one or more of 2-hydroxy-4-n-octyloxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-5-methylphenyl) benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl) benzotriazole, 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-octoxyphenol.

8. The polyolefin photovoltaic adhesive film according to claim 1, wherein, The vacuum lamination conditions are that the lamination temperature is 142 - 155 °C, the vacuum pumping time is 5 - 10 minutes, and the lamination time is 12 - 18 minutes.

9. The polyolefin photovoltaic adhesive film according to claim 1 or 2, wherein The structure of the polyolefin photovoltaic film prepared from the above materials includes a single layer of POE, two or more layers of POE, POE / EVA, EVA / POE / EVA, POE / TPO, POE / POP.

10. A method for preparing the polyolefin photovoltaic adhesive film according to any one of claims 1-9, characterized in that, The method includes the following steps: Step 1: Put the polyolefin elastomer and the modified resin into a mixer according to the ratio and physically mix and stir for 10 - 30 min; Step 2: Add the peroxide crosslinking agent to the above resin mixture and stir for 30 - 60 min; Step 3: Disperse the co-crosslinking agent, silane oligomer coupling agent, silane end-capping agent, antioxidant, light stabilizer, and ultraviolet absorber with a high-speed disperser for 30 - 60 min; Step 4: Add the additives evenly mixed in Step 3 to the resin mixture described in Step 2 and continue to stir for 6 - 12 h until the additives are completely absorbed; Step 5: Feed the material completely absorbed in Step 4 into a screw extruder or calender through a feeding system and cast or calender it into a film at 80 - 120 °C.

11. The preparation method according to claim 10, characterized in that, The thickness of the polyolefin photovoltaic adhesive film is 0.1 to 1 mm, and the grammage is 100 - 800 g / m 2 .

12. Use of the polyolefin photovoltaic film according to any one of claims 1 to 9 for encapsulating photovoltaic cells.

Images