EPE three-layer co-extrusion adhesive film as well as preparation method and application thereof

Abstract

The invention relates to the technical field of photovoltaic packaging materials, in particular to an EPE three-layer co-extrusion adhesive film and a preparation method and application thereof. The EPE three-layer co-extrusion adhesive film comprises a first EVA layer, a POE layer and a second EVA layer which are arranged in sequence; the first EVA layer and the second EVA layer respectively and independently comprise EVA resin, modified EVA resin, a compatilizer, a cross-linking agent, an assistant cross-linking agent, a silane coupling agent and an antioxidant; the POE layer comprises modified POE resin, a compatilizer, a cross-linking agent, an assistant cross-linking agent, a silane coupling agent and an antioxidant; the modified EVA resin comprises at least two kinds of EVA resin grafted and modified by polybutadiene with different molecular weights; the modified POE resin comprises at least two kinds of POE resin grafted and modified by polybutadiene with different vinyl contents. According to the EPE three-layer co-extrusion adhesive film disclosed by the invention, the auxiliaries are not easy to migrate, and meanwhile, the EPE three-layer co-extrusion adhesive film has high adhesive property, high crosslinking degree, high water resistance, aging resistance and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic packaging materials, and in particular to an EPE three-layer co-extruded film and a preparation method and application thereof. Background Art

[0002] In recent years, the rapid development of the photovoltaic industry has driven the continuous upgrading and optimization of photovoltaic films. The types of photovoltaic films mainly include EVA, POE and EPE. POE film not only has excellent electrical insulation and water vapor barrier properties, but also can effectively resist the PID effect. POE film also has the characteristics of high elasticity, high strength and low temperature resistance, and will not produce corrosive acidic substances. However, compared with EVA film, the process of POE film is complicated and the cost is high. EPE three-layer co-extruded film combines the advantages and disadvantages of EVA film and POE film, providing more combination options. Compared with EVA film, EPE film performs well in anti-PID performance, and has comprehensive characteristics such as high water barrier ability, resistance to ultraviolet radiation, and resistance to wet and hot aging; compared with POE film, EPE film retains the convenience of lamination process and high adhesion of EVA material, and the process window is more suitable, which improves production efficiency. In addition, the use of EPE encapsulation film can reduce the use of POE material, which not only reduces production costs, but also alleviates the problem of limited raw material supply.

[0003] Although EPE co-extruded film has many advantages mentioned above, there are also certain problems in the actual application process. First, EPE co-extruded film is essentially made by casting and extruding EVA and POE materials in a high-temperature molten state, while EVA and POE are two completely different polymer materials with different glass transition temperatures. When the ambient temperature is below -20°C, EVA hardens while POE still maintains elasticity. Second, the difference in molecular polarity makes the absorption degree and rate of EVA and POE materials to additives significantly different, resulting in inherent differences in the cross-linking rates of EVA and POE, which requires the introduction of different proportions of functional additives in the two materials during formula design. After the EPE film is produced, because the polar characteristics of EVA are more compatible with most additives, this causes the EVA layer of EPE to continuously absorb the effective additives in the POE layer, causing changes in the internal structural properties of the film. Third, after the migration of the additive, the cross-linking speed of POE slows down, resulting in a decrease in the degree of cross-linking of the POE layer, which easily leads to the risk of delamination between the film layers and delamination between the film and the glass or battery cell. In addition, during the long-term aging process, the difference in water vapor permeability between the POE layer and the EVA layer and the fact that EVA is more susceptible to aging and releases acidic substances, the external invading water vapor and internal acidic substances are easily enriched at the interface of the two materials, making the interfacial bonding strength increasingly weak, causing the risk of delamination.

[0004] Therefore, it is of great significance to prepare an EPE three-layer co-extruded film with a stable EVA / POE / EVA three-layer structure, in which the additives are not easy to migrate, easy to produce and process, and having high adhesion, high cross-linking degree, high water resistance, and excellent aging resistance.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] One object of the present invention is to provide an EPE three-layer co-extruded film, wherein the EVA and POE structures are stable, the additives are not easy to migrate, and the film has high adhesion performance, high cross-linking degree, high water resistance and aging resistance.

[0007] Another object of the present invention is to provide a method for preparing the EPE three-layer co-extruded film.

[0008] Another object of the present invention is to provide an application of an EPE three-layer co-extruded film in the preparation of photovoltaic modules.

[0009] In order to achieve the above-mentioned object of the present invention, the present invention provides an EPE three-layer co-extruded film, comprising a first EVA layer, a POE layer and a second EVA layer arranged in sequence;

[0010] The first EVA layer and the second EVA layer each independently include the following components by weight: 50-85 parts of EVA resin, 15-45 parts of modified EVA resin, 1-5 parts of compatibilizer, 0.1-2 parts of crosslinking agent, 0.1-2 parts of auxiliary crosslinking agent, 0.1-2 parts of silane coupling agent and 0.01-1 parts of antioxidant;

[0011] The POE layer comprises the following components by weight: 100 parts of modified POE resin, 1 to 5 parts of compatibilizer, 0.1 to 2 parts of crosslinking agent, 0.1 to 2 parts of auxiliary crosslinking agent, 0.1 to 2 parts of silane coupling agent and 0.01 to 1 part of antioxidant;

[0012] The modified EVA resin comprises at least two EVA resins graft-modified by polybutadiene with different molecular weights; and the modified POE resin comprises at least two POE resins graft-modified by polybutadiene with different vinyl contents.

[0013] In a specific embodiment of the present invention, among the polybutadienes with different molecular weights, the molecular weight of the polybutadiene is 1400-8000 g / mol.

[0014] In a specific embodiment of the present invention, in the polybutadiene with different vinyl contents, the vinyl content of the polybutadiene is 18% to 70%.

[0015] In a specific embodiment of the present invention, the modified EVA resin includes a first modified EVA resin, a second modified EVA resin and a third modified EVA resin; the first modified EVA resin, the second modified EVA resin and the third modified EVA resin are respectively EVA resins grafted and modified with a first polybutadiene, a second polybutadiene and a third polybutadiene, the molecular weight of the first polybutadiene is 3800 to 4100 g / mol, the molecular weight of the second polybutadiene is 1800 to 2000 g / mol, and the molecular weight of the third polybutadiene is 1400 to 1600 g / mol.

[0016] In a specific embodiment of the present invention, the modified EVA resin includes 5 to 15 parts by weight of a first modified EVA resin, 5 to 15 parts by weight of a second modified EVA resin, and 5 to 15 parts by weight of a third modified EVA resin. Furthermore, the amounts of the first modified EVA resin, the second modified EVA resin, and the third modified EVA resin are increased in sequence.

[0017] In a specific embodiment of the present invention, the modified POE resin includes a first modified POE resin, a second modified POE resin and a third modified POE resin; the first modified POE resin, the second modified POE resin and the third modified POE resin are POE resins grafted and modified with a fourth polybutadiene, a fifth polybutadiene and a sixth polybutadiene, respectively, the fourth polybutadiene has a vinyl content of 65% to 70%, the fifth polybutadiene has a vinyl content of 50% to 60%, and the sixth polybutadiene has a vinyl content of 18% to 25%.

[0018] In a specific embodiment of the present invention, the modified POE resin includes 10 to 40 parts by weight of a first modified POE resin, 20 to 40 parts by weight of a second modified POE resin, and 30 to 60 parts by weight of a third modified POE resin. Furthermore, the amounts of the first modified POE resin, the second modified POE resin, and the third modified POE resin are increased in sequence.

[0019] In a specific embodiment of the present invention, the modified EVA resin is mainly prepared by extrusion granulation of EVA resin, peroxide initiator and polybutadiene in a mass ratio of 100:(0.01-0.5):(1-10).

[0020] In a specific embodiment of the present invention, the modified POE resin is mainly prepared by extrusion granulation of POE resin, peroxide initiator and polybutadiene in a mass ratio of 100:(0.01-0.5):(1-10).

[0021] In a specific embodiment of the present invention, the thickness of the first EVA layer and the second EVA layer are independently 100-200 μm; the thickness of the POE layer is 100-300 μm.

[0022] In a specific embodiment of the present invention, the compatibilizer includes at least one of EPDM rubber, EPDM rubber and butadiene-styrene copolymer. Further, the butadiene-styrene copolymer has a vinyl content of 20% to 70% and a molecular weight of 3000 to 9000 g / mol.

[0023] Another aspect of the present invention provides a method for preparing any one of the above-mentioned EPE three-layer co-extruded films, comprising the following steps:

[0024] According to the composition and ingredients of the first EVA layer, the POE layer and the second EVA layer, melt co-extrusion is carried out to obtain the EPE three-layer co-extruded film.

[0025] Another aspect of the present invention provides use of any one of the above-mentioned EPE three-layer co-extruded films in the preparation of photovoltaic modules.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) In the EPE three-layer co-extruded film of the present invention, the EVA layer is introduced with polybutadiene grafted modified EVA resin with different molecular weights, which can make the microstructure of the EVA layer more compact under physical action; on the other hand, some vinyls that do not participate in the grafting reaction participate in the cross-linking of the EVA layer during the later high-temperature lamination vulcanization process, further increasing the cross-linking degree of the EVA layer, forming a more compact three-dimensional network structure, and improving the water vapor barrier capacity of the EVA layer;

[0028] (2) In the EPE three-layer co-extruded film of the present invention, the POE layer is introduced with a polybutadiene graft-modified POE resin having different vinyl contents, which can reduce the rate at which the POE layer additive migrates to the EVA layer; and the polybutadiene long chain used in the modified POE resin can interpenetrate with the polybutadiene long chain of the modified EVA resin into each other's layers, thereby improving the compatibility of the POE layer and the EVA layer. During high-temperature lamination, the vinyl groups at the interface of the two layers react and cross-link, thereby improving the adhesion of the two layers and avoiding delamination during the aging process, thereby greatly improving the comprehensive properties of the EPE film.

[0029] (3) The EVA layer of the present invention adopts a certain amount of compatibilizer, which can further improve the barrier properties of the EVA layer, reduce the water vapor permeability of the EPE three-layer co-extruded film, and increase the cross-linking degree of the EVA layer, thereby improving the chemical resistance, moisture and heat aging resistance and electrical insulation properties of the EPE film; the POE layer of the present invention adopts a certain amount of compatibilizer to increase the rigidity and hydrophobicity of the POE layer, avoid the situation where the POE layer is squeezed out and thinned by the EVA layer during the lamination process, and improve the barrier properties of EPE. DETAILED DESCRIPTION

[0030] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments, but it will be appreciated by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work, all belong to the scope of protection of the present invention. If specific conditions are not indicated in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0031] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0032] In one aspect, the present invention provides an EPE three-layer co-extruded film, comprising a first EVA layer, a POE layer and a second EVA layer arranged in sequence;

[0033] The first EVA layer and the second EVA layer each independently include the following components by weight: 50-85 parts of EVA resin, 15-45 parts of modified EVA resin, 1-5 parts of compatibilizer, 0.1-2 parts of crosslinking agent, 0.1-2 parts of auxiliary crosslinking agent, 0.1-2 parts of silane coupling agent and 0.01-1 parts of antioxidant;

[0034] The POE layer includes the following components by weight: 100 parts of modified POE resin, 1 to 5 parts of compatibilizer, 0.1 to 2 parts of crosslinking agent, 0.1 to 2 parts of auxiliary crosslinking agent, 0.1 to 2 parts of silane coupling agent and 0.01 to 1 part of antioxidant;

[0035] The modified EVA resin includes at least two EVA resins graft-modified by polybutadiene with different molecular weights; the modified POE resin includes at least two POE resins graft-modified by polybutadiene with different vinyl contents.

[0036] The EPE three-layer co-extruded film of the present invention has stable EVA and POE structures, and the additives are not easy to migrate. At the same time, it has high bonding performance, high cross-linking degree, high water resistance and aging resistance.

[0037] Among them, EVA resins modified by polybutadiene grafting with different molecular weights are introduced into the EVA layer. The EVA resin modified by polybutadiene grafting with relatively high molecular weight has a longer molecular chain that can form a large number of entangled segments with the EVA resin matrix and the modified EVA resin, and the EVA resin modified by polybutadiene grafting with relatively low molecular weight has a shorter molecular chain that can be interspersed in the gaps between the EVA resin matrix and the modified EVA resin for further filling. These entangled segments and gap-filling segments make the microstructure of the EVA layer more compact under physical action. On the other hand, some vinyl groups that do not participate in the grafting reaction participate in the cross-linking of the EVA layer during the later high-temperature lamination vulcanization process, further increasing the cross-linking degree of the EVA layer, forming a denser three-dimensional network structure, and improving the water vapor barrier capacity of the EVA layer. The EVA layer of the present invention adopts a certain amount of compatibilizer, which can further improve the barrier performance of the EVA layer, reduce the water vapor permeability of the EPE three-layer co-extruded film, and increase the cross-linking degree of the EVA layer, thereby improving the chemical resistance, moisture and heat aging resistance and electrical insulation performance of the EPE film.

[0038] For example, in different embodiments, in the first EVA layer and the second EVA layer, the amounts of the components in parts by weight may be as follows:

[0039] The amount of EVA resin can be 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts or a range consisting of any two of them;

[0040] The amount of the modified EVA resin can be 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts or a range consisting of any two of them;

[0041] The amount of the compatibilizer can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts or a range consisting of any two of them;

[0042] The amount of the cross-linking agent can be 0.1 part, 0.3 part, 0.5 part, 0.8 part, 1 part, 1.5 parts, 2 parts or any two thereof;

[0043] The amount of the auxiliary cross-linking agent can be 0.1 part, 0.3 part, 0.5 part, 0.8 part, 1 part, 1.5 parts, 2 parts or any two thereof;

[0044] The amount of the silane coupling agent can be 0.1 part, 0.3 part, 0.5 part, 0.8 part, 1 part, 1.5 parts, 2 parts or any two thereof;

[0045] The amount of the antioxidant can be 0.01 part, 0.05 part, 0.1 part, 0.5 part, 0.8 part, 1 part or a range consisting of any two of them.

[0046] It can be understood that the compositions of the first EVA layer and the second EVA layer may be the same or different, as long as their respective compositions remain within the scope of the present invention.

[0047] In the EPE three-layer co-extruded film of the present invention, a POE resin grafted with polybutadiene having different vinyl contents is introduced into the POE layer, which can further increase the polarity of the POE layer, adsorb the auxiliary agent of the POE layer, and lock the auxiliary agent in the POE layer, thereby reducing the rate at which the POE layer auxiliary agent migrates to the EVA layer; and the long polybutadiene chain used by the modified POE resin can interpenetrate each other's layers with the long polybutadiene chain of the modified EVA resin, and the layers are mutually interlocked, and mutually adsorbed and entangled under the polar action of the free vinyl, thereby improving the compatibility of the POE layer and the EVA layer, and during high-temperature lamination, the vinyl at the interface of the two layers reacts and crosslinks with each other, thereby improving the adhesion of the two layers, avoiding delamination during aging, and greatly improving the comprehensive performance of the EPE film. The POE layer of the present invention adopts a certain amount of compatibilizer to increase the rigidity and hydrophobicity of the POE layer, avoid the situation in which the POE layer is squeezed out and thinned by the EVA layer during lamination, and improve the barrier properties of the EPE.

[0048] In addition, the POE layer of the present invention is entirely made of modified POE resin, which can improve the problem of slow absorption of additives by POE resin, greatly reduce mixing time, and improve production efficiency.

[0049] For example, in different embodiments, in the POE layer, by weight, compared to 100 parts by weight of the modified POE resin, the amounts of the remaining components may be as follows:

[0050] The amount of the compatibilizer can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts or a range consisting of any two of them;

[0051] The amount of the cross-linking agent can be 0.1 part, 0.3 part, 0.5 part, 0.8 part, 1 part, 1.5 parts, 2 parts or any two thereof;

[0052] The amount of the auxiliary cross-linking agent can be 0.1 part, 0.3 part, 0.5 part, 0.8 part, 1 part, 1.5 parts, 2 parts or any two thereof;

[0053] The amount of the silane coupling agent can be 0.1 part, 0.3 part, 0.5 part, 0.8 part, 1 part, 1.5 parts, 2 parts or any two thereof;

[0054] The amount of the antioxidant can be 0.01 part, 0.05 part, 0.1 part, 0.5 part, 0.8 part, 1 part or a range consisting of any two of them.

[0055] In a specific embodiment of the present invention, among the polybutadienes with different molecular weights, the molecular weight of the polybutadiene is 1400-8000 g / mol.

[0056] For example, in different embodiments, in polybutadiene of different molecular weights, the molecular weight of polybutadiene can be 1400 g / mol, 1600 g / mol, 1800 g / mol, 2000 g / mol, 2500 g / mol, 3000 g / mol, 3500 g / mol, 4000 g / mol, 4500 g / mol, 5000 g / mol, 5500 g / mol, 6000 g / mol, 6500 g / mol, 7000 g / mol, 7500 g / mol, 8000 g / mol or a range consisting of any two of them.

[0057] In a specific embodiment of the present invention, among the polybutadienes with different molecular weights, the molecular weight difference of the polybutadienes is 300-3000 g / mol.

[0058] In a specific embodiment of the present invention, the difference in vinyl content of polybutadiene with different molecular weights is ≤5%. The polybutadiene used for EVA resin modification has different molecular weights and the vinyl content thereof can be close to or the same.

[0059] In a specific embodiment of the present invention, in the polybutadiene with different vinyl contents, the vinyl content of the polybutadiene is 18% to 70%.

[0060] For example, in different embodiments, in polybutadiene with different vinyl contents, the vinyl content of the polybutadiene can be 18%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70% or a range consisting of any two thereof.

[0061] In a specific embodiment of the present invention, in the polybutadienes with different vinyl contents, the difference in vinyl content of the polybutadienes is 30% to 60%.

[0062] In the polybutadienes with different vinyl contents, the molecular weight of the polybutadiene is not limited and can be the same or different.

[0063] In a specific embodiment of the present invention, the modified EVA resin includes a first modified EVA resin, a second modified EVA resin and a third modified EVA resin; the first modified EVA resin, the second modified EVA resin and the third modified EVA resin are respectively EVA resins grafted and modified with a first polybutadiene, a second polybutadiene and a third polybutadiene, the molecular weight of the first polybutadiene is 3800 to 4100 g / mol, the molecular weight of the second polybutadiene is 1800 to 2000 g / mol, and the molecular weight of the third polybutadiene is 1400 to 1600 g / mol.

[0064] In a specific embodiment of the present invention, the modified EVA resin includes 5 to 15 parts by weight of a first modified EVA resin, 5 to 15 parts by weight of a second modified EVA resin, and 5 to 15 parts by weight of a third modified EVA resin.

[0065] For example, in different embodiments, in the modified EVA resin, the amounts of each component in parts by weight may be as follows:

[0066] The amount of the first modified EVA resin can be 5 parts, 8 parts, 10 parts, 12 parts, 15 parts or a range consisting of any two of them;

[0067] The amount of the second modified EVA resin can be 5 parts, 8 parts, 10 parts, 12 parts, 15 parts or a range consisting of any two of them;

[0068] The amount of the third modified EVA resin can be 5 parts, 8 parts, 10 parts, 12 parts, 15 parts or a range consisting of any two of them.

[0069] In a specific embodiment of the present invention, the amounts of the first modified EVA resin, the second modified EVA resin and the third modified EVA resin are increased in sequence. The amounts that meet the above conditions are more conducive to improving the comprehensive properties of the EPE three-layer co-extruded film.

[0070] In a specific embodiment of the present invention, the modified POE resin includes a first modified POE resin, a second modified POE resin and a third modified POE resin; the first modified POE resin, the second modified POE resin and the third modified POE resin are POE resins grafted with a fourth polybutadiene, a fifth polybutadiene and a sixth polybutadiene, respectively, the fourth polybutadiene has a vinyl content of 65% to 70%, the fifth polybutadiene has a vinyl content of 50% to 60%, and the sixth polybutadiene has a vinyl content of 18% to 25%.

[0071] In a specific embodiment of the present invention, the modified POE resin includes 10 to 40 parts by weight of a first modified POE resin, 20 to 40 parts by weight of a second modified POE resin, and 30 to 60 parts by weight of a third modified POE resin.

[0072] For example, in different embodiments, in the modified POE resin, the amounts of each component in parts by weight may be as follows:

[0073] The amount of the first modified POE resin can be 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts or a range consisting of any two of them;

[0074] The amount of the second modified POE resin can be 20 parts, 25 parts, 30 parts, 35 parts, 40 parts or a range consisting of any two thereof;

[0075] The amount of the third modified POE resin can be 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts or a range consisting of any two of them.

[0076] In a specific embodiment of the present invention, the dosage of the first modified POE resin, the second modified POE resin and the third modified POE resin increases in sequence. The dosage that meets the above conditions is more conducive to improving the comprehensive performance of the EPE three-layer co-extruded film, avoiding excessive POE resin grafted with high vinyl content polybutadiene, resulting in excessive crosslinking of the film, increased hardness, and poor adhesion and aging properties.

[0077] In a specific embodiment of the present invention, the modified EVA resin is mainly prepared by extrusion granulation of EVA resin, peroxide initiator and polybutadiene in a mass ratio of 100:(0.01-0.5):(1-10).

[0078] In a specific embodiment of the present invention, the modified POE resin is mainly prepared by extrusion granulation of POE resin, peroxide initiator and polybutadiene in a mass ratio of 100:(0.01-0.5):(1-10).

[0079] In actual operation, in the preparation of modified EVA resin and modified POE resin, the peroxide initiator can be at least one of dibenzoyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, diisopropylbenzene peroxide and tert-butylperoxycarbonate-2-ethylhexyl ester. The amount of peroxide initiator can be 0.01%, 0.1%, 0.3%, 0.4%, 0.5% of the mass of EVA resin or POE resin, or a range consisting of any two thereof; the amount of polybutadiene can be 1%, 3%, 5%, 8%, 10% of the mass of EVA resin or POE resin, or a range consisting of any two thereof.

[0080] In the preparation of modified EVA resin and modified POE resin, the selection of specific polybutadiene types is adjusted and selected according to the aforementioned modification requirements. For example, the first modified EVA resin is prepared by using the first polybutadiene, the second modified EVA resin is prepared by using the second polybutadiene, and the third modified EVA resin is prepared by using the third polybutadiene; the first modified POE resin is prepared by using the fourth polybutadiene, the second modified POE resin is prepared by using the fifth polybutadiene, and the third modified POE resin is prepared by using the sixth polybutadiene.

[0081] In a specific embodiment of the present invention, the preparation of modified EVA resin or modified POE resin may include the following steps: (1) uniformly mixing a peroxide initiator and a corresponding polybutadiene, heating the mixture to 60-80°C, stirring the mixture at a constant speed for 0.1-2h, and then cooling the mixture to room temperature; (2) setting eleven temperature zones of a twin-screw extruder, wherein the temperature of the first four temperature zones is 70-140°C, the temperature of the middle two temperature zones is 160-180°C, and the temperature of the last two temperature zones is 140-100°C; (3) controlling the temperature for 1-2h according to the set temperature, then adding EVA resin or POE resin to wash the machine for 1-2h, and then adding the material obtained in step (1) to the feed port between the fourth temperature zone and the fifth temperature zone, and extruding and granulating the mixture to obtain the corresponding modified EVA resin or modified POE resin.

[0082] In a specific embodiment of the present invention, the thickness of the first EVA layer and the second EVA layer are independently 100-200 μm; the thickness of the POE layer is 100-300 μm.

[0083] For example, in different embodiments, the thickness of the first EVA layer and the second EVA layer can be independently selected from 100 μm, 120 μm, 150 μm, 180 μm, 200 μm or a range consisting of any two thereof; the thickness of the POE layer can be 100 μm, 150 μm, 200 μm, 250 μm, 300 μm or a range consisting of any two thereof.

[0084] In a specific embodiment of the present invention, the compatibilizer includes at least one of ethylene propylene diene monomer rubber, ethylene propylene diene monomer rubber and butadiene-styrene copolymer.

[0085] In a specific embodiment of the present invention, the compatibilizer of the EVA layer includes at least one of EPDM and / or EPDM. Introducing a certain amount of EPDM into the EVA layer can further improve the barrier properties of the EVA layer, and reduce the water vapor transmission rate of the EPE three-layer co-extruded film to 9.04 g / (m 2 ·24h), and at the same time improve the cross-linking degree of the EVA layer, and enhance the chemical resistance, heat and humidity aging resistance and electrical insulation performance of the EPE three-layer co-extruded film.

[0086] In a specific embodiment of the present invention, the compatibilizer of the POE layer includes butadiene-styrene copolymer. Further, the butadiene-styrene copolymer has a vinyl content of 20% to 70% and a molecular weight of 3000 to 9000 g / mol.

[0087] For example, in different embodiments, the vinyl content of the butadiene-styrene copolymer can be 20%, 30%, 40%, 50%, 60%, 70% or a range consisting of any two thereof, and the molecular weight can be 3000 g / mol, 4000 g / mol, 5000 g / mol, 6000 g / mol, 8000 g / mol, 9000 g / mol or a range consisting of any two thereof.

[0088] Butadiene-styrene copolymer is introduced into the POE layer as a compatibilizer, and the styrene group in butadiene-styrene is used to increase the rigidity and hydrophobicity of the POE layer, thereby preventing the POE layer from being squeezed out and thinned by the EVA layer during the lamination process, thereby improving the barrier properties of EPE.

[0089] For example, in different embodiments, the types of the remaining additives in the first EVA layer, the second EVA layer and the POE layer can be referred to as follows:

[0090] The cross-linking agent includes at least one of tert-amyl peroxy (2-ethylhexyl) carbonate, tert-butyl peroxy-2-ethylhexyl carbonate, 1,1-bis (tert-butylperoxy)-3,3,5-trimethylcyclohexane and 2,5-dimethyl-2,5-bis (tert-butylperoxy) hexane;

[0091] The auxiliary cross-linking agent includes at least one of trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, triallyl isocyanurate and diallyl phthalate;

[0092] The silane coupling agent includes at least one of vinyl trimethoxysilane, vinyl triethoxysilane, γ-aminopropyl triethoxysilane, γ-aminopropyl trimethoxysilane, triacetoxy vinyl silane, vinyl tri(2-methoxyethoxy) silane, γ-glycidyloxypropyl trimethoxysilane and γ-(methacryloyloxy)propyl trimethoxysilane;

[0093] The antioxidant includes at least one of antioxidant 1035 , antioxidant 168 , antioxidant 1010 , and antioxidant 1098 .

[0094] Another aspect of the present invention provides a method for preparing any one of the above-mentioned EPE three-layer co-extruded films, comprising the following steps:

[0095] According to the composition of the first EVA layer, the POE layer and the second EVA layer, melt co-extrusion is carried out to obtain an EPE three-layer co-extruded film.

[0096] Another aspect of the present invention provides use of any one of the above-mentioned EPE three-layer co-extruded films in the preparation of photovoltaic modules.

[0097] Some of the material information used in the following specific embodiments of the present invention may be as follows, but is not limited thereto:

[0098] EVA resin: Sailbond, UE2825;

[0099] POE resin: SK company, 8813V;

[0100] Butadiene-styrene copolymer Ricon 181: Shanghai Wandao Chemical Co., Ltd., Ricon 181, ethylene content 20%-40%, styrene content 20%-30%, molecular weight 3200g / mol;

[0101] Butadiene-styrene copolymer Ricon 184: Shanghai Wandao Chemical Co., Ltd., Ricon 184, ethylene content 20%-40%, styrene content 17%-27%, molecular weight 8600g / mol;

[0102] The information of polybutadiene is shown in Table 1.

[0103] Table 1 Information of different polybutadiene

[0104] serial number model Manufacturer Ethylene content Molecular weight 1 Ricon 131 Shanghai Wandao Chemical Co., Ltd. 18％ 4500g / mol 2 Ricon 130 Shanghai Wandao Chemical Co., Ltd. 20％ 2500g / mol 3 Ricon 134 Shanghai Wandao Chemical Co., Ltd. 35％ 8000g / mol 4 Ricon 142 Shanghai Wandao Chemical Co., Ltd. 55％ 4100g / mol 5 Ricon 150 Shanghai Wandao Chemical Co., Ltd. 70％ 3900g / mol 6 Ricon 156 Shanghai Wandao Chemical Co., Ltd. 70％ 1400g / mol 7 Ricon 157 Shanghai Wandao Chemical Co., Ltd. 70％ 1800g / mol

[0105] Depending on the type of polybutadiene used for modification, different modified EVA resins are named EVA-131 resin, EVA-130 resin, EVA-134 resin, EVA-142 resin, EVA-150 resin, EVA-156 resin, and EVA-157 resin, and different modified POE resins are named POE-131 resin, POE-130 resin, POE-134 resin, POE-142 resin, POE-150 resin, POE-156 resin, and POE-157 resin.

[0106] Taking EVA-131 resin as an example, the preparation method thereof is described. The preparation method of EVA-131 resin comprises the following steps:

[0107] (1) The peroxide initiator 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and polybutadiene Ricon131 were mixed uniformly and heated to 70°C and stirred at a constant speed for 1 hour, and then cooled to room temperature;

[0108] (2) Eleven temperature zones are set for the twin-screw extruder, namely, zone I 80-85°C, zone II 85-95°C, zone III 100-120°C, zone IV 120-140°C, zone V 160-180°C, zone VI 160-180°C, zone VII 160-180°C, zone VIII 160-180°C, zone IX 160-180°C, zone X and zone IV 120-140°C, and die head 110°C; among which, the first four low-temperature feeding sections make the EVA resin become a molten state in the screw as soon as possible, the middle five high-temperature sections are EVA grafting chemical reaction sections, and the last two are cooling sections.

[0109] (3) First, the temperature is controlled according to the set temperature for 1.5 hours, then EVA resin is added to wash the machine for 1.5 hours, and then the material obtained in step (1) is added to the feed port between the fourth temperature zone and the fifth temperature zone, and extrusion granulation is performed and cooled;

[0110] (4) The modified EVA resin obtained in step (3) is placed in a constant temperature kettle at 40-55° C., stirred and dried, and moisture is removed, and cooled to obtain EVA-131 resin.

[0111] EVA-130 resin, EVA-134 resin, EVA-142 resin, EVA-150 resin, EVA-156 resin, and EVA-157 resin can be prepared by the above method, except that Ricon 131 can be replaced by an equal weight of Ricon 130, Ricon 134, Ricon 142, Ricon150, Ricon 156, and Ricon 157. POE-131 resin can be prepared by the above method, except that EVA resin can be replaced by an equal weight of POE resin. POE-130 resin, POE-134 resin, POE-142 resin, POE-150 resin, POE-156 resin, and POE-157 resin can be prepared by the above method, except that EVA resin can be replaced by an equal weight of POE resin, and Ricon 131 can be replaced by an equal weight of Ricon 130, Ricon 134, Ricon 142, Ricon 150, Ricon 156, and Ricon 157 is enough.

[0112] The following specific examples and comparative examples include but are not limited to EVA-150 resin, EVA-156 resin, EVA-157 resin, POE-130 resin, POE-142 resin, and POE-156 resin.

[0113] Example 1

[0114] This embodiment provides an EPE three-layer co-extruded film, comprising a first EVA layer, a POE layer and a second EVA layer arranged in sequence, wherein the thickness of the first EVA layer and the second EVA layer are both 150 μm, and the thickness of the POE layer is 250 μm.

[0115] The first EVA layer and the second EVA layer both include the following components in parts by weight: 55 parts of EVA resin, 15 parts of EVA-156 resin, 15 parts of EVA-157 resin, 15 parts of EVA-150 resin, 3 parts of 4045 ethylene propylene rubber, 0.5 parts of tert-amyl peroxide-2-ethylhexyl carbonate, 0.5 parts of trimethylolpropane triacrylate, 0.4 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0116] The POE layer includes the following components in parts by weight: 50 parts of POE-130 resin, 30 parts of POE-142 resin, 20 parts of POE-156 resin, 3 parts of Ricon 181 resin, 0.9 parts of tert-amyl peroxy-2-ethylhexyl carbonate, 0.7 parts of trimethylolpropane triacrylate, 0.2 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0117] The preparation method of the EPE three-layer co-extruded film of the present embodiment comprises the following steps: melt co-extrusion is performed according to the composition ingredients of the first EVA layer, the POE layer and the second EVA layer to obtain the EPE three-layer co-extruded film; wherein the melt co-extrusion includes: zone I 50-100°C, zone II 50-100°C, zone III 50-100°C, zone IV 50-100°C, zone V 50-100°C, zone VI 50-100°C, and die head 115°C.

[0118] Example 2

[0119] This embodiment provides an EPE three-layer co-extruded film, comprising a first EVA layer, a POE layer and a second EVA layer arranged in sequence, wherein the thickness of the first EVA layer and the second EVA layer are both 150 μm, and the thickness of the POE layer is 250 μm.

[0120] The first EVA layer and the second EVA layer both include the following components in parts by weight: 79 parts of EVA resin, 7 parts of EVA-156 resin, 7 parts of EVA-157 resin, 7 parts of EVA-150 resin, 3 parts of 4045 ethylene propylene rubber, 0.5 parts of tert-amyl peroxide-2-ethylhexyl carbonate, 0.5 parts of trimethylolpropane triacrylate, 0.4 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0121] The POE layer includes the following components in parts by weight: 50 parts of POE-130 resin, 30 parts of POE-142 resin, 20 parts of POE-156 resin, 3 parts of Ricon 181 resin, 0.9 parts of tert-amyl peroxy-2-ethylhexyl carbonate, 0.7 parts of trimethylolpropane triacrylate, 0.2 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0122] The preparation method of the EPE three-layer co-extruded film of this embodiment is the same as that of Embodiment 1.

[0123] Example 3

[0124] This embodiment provides an EPE three-layer co-extruded film, comprising a first EVA layer, a POE layer and a second EVA layer arranged in sequence, wherein the thickness of the first EVA layer and the second EVA layer are both 150 μm, and the thickness of the POE layer is 250 μm.

[0125] The first EVA layer and the second EVA layer both include the following components in parts by weight: 70 parts of EVA resin, 5 parts of EVA-156 resin, 10 parts of EVA-157 resin, 15 parts of EVA-150 resin, 3 parts of 4045 ethylene propylene rubber, 0.5 parts of tert-amyl peroxide-2-ethylhexyl carbonate, 0.5 parts of trimethylolpropane triacrylate, 0.4 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0126] The POE layer includes the following components in parts by weight: 50 parts of POE-130 resin, 30 parts of POE-142 resin, 20 parts of POE-156 resin, 3 parts of Ricon 181 resin, 0.9 parts of tert-amyl peroxy-2-ethylhexyl carbonate, 0.7 parts of trimethylolpropane triacrylate, 0.2 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0127] The preparation method of the EPE three-layer co-extruded film of this embodiment is the same as that of Embodiment 1.

[0128] Example 4

[0129] This embodiment provides an EPE three-layer co-extruded film, comprising a first EVA layer, a POE layer and a second EVA layer arranged in sequence, wherein the thickness of the first EVA layer and the second EVA layer are both 150 μm, and the thickness of the POE layer is 250 μm.

[0130] The first EVA layer and the second EVA layer both include the following components in parts by weight: 70 parts of EVA resin, 15 parts of EVA-156 resin, 10 parts of EVA-157 resin, 5 parts of EVA-150 resin, 3 parts of 4045 ethylene propylene rubber, 0.5 parts of tert-amyl peroxide-2-ethylhexyl carbonate, 0.5 parts of trimethylolpropane triacrylate, 0.4 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0131] The POE layer includes the following components in parts by weight: 50 parts of POE-130 resin, 30 parts of POE-142 resin, 20 parts of POE-156 resin, 3 parts of Ricon 181 resin, 0.9 parts of tert-amyl peroxy-2-ethylhexyl carbonate, 0.7 parts of trimethylolpropane triacrylate, 0.2 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0132] The preparation method of the EPE three-layer co-extruded film of this embodiment is the same as that of Embodiment 1.

[0133] Example 5

[0134] This embodiment provides an EPE three-layer co-extruded film, comprising a first EVA layer, a POE layer and a second EVA layer arranged in sequence, wherein the thickness of the first EVA layer and the second EVA layer are both 150 μm, and the thickness of the POE layer is 250 μm.

[0135] The first EVA layer and the second EVA layer both include the following components in parts by weight: 70 parts of EVA resin, 15 parts of EVA-156 resin, 10 parts of EVA-157 resin, 5 parts of EVA-150 resin, 3 parts of 4045 ethylene propylene rubber, 0.5 parts of tert-amyl peroxide-2-ethylhexyl carbonate, 0.5 parts of trimethylolpropane triacrylate, 0.4 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0136] The POE layer includes the following components in parts by weight: 60 parts of POE-130 resin, 30 parts of POE-142 resin, 10 parts of POE-156 resin, 3 parts of Ricon 181 resin, 0.9 parts of tert-amyl peroxy-2-ethylhexyl carbonate, 0.7 parts of trimethylolpropane triacrylate, 0.2 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0137] The preparation method of the EPE three-layer co-extruded film of this embodiment is the same as that of Embodiment 1.

[0138] Example 6

[0139] This embodiment provides an EPE three-layer co-extruded film, comprising a first EVA layer, a POE layer and a second EVA layer arranged in sequence, wherein the thickness of the first EVA layer and the second EVA layer are both 150 μm, and the thickness of the POE layer is 250 μm.

[0140] The first EVA layer and the second EVA layer both include the following components in parts by weight: 70 parts of EVA resin, 15 parts of EVA-156 resin, 10 parts of EVA-157 resin, 5 parts of EVA-150 resin, 3 parts of 4045 ethylene propylene rubber, 0.5 parts of tert-amyl peroxide-2-ethylhexyl carbonate, 0.5 parts of trimethylolpropane triacrylate, 0.4 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0141] The POE layer includes the following components in parts by weight: 40 parts of POE-130 resin, 40 parts of POE-142 resin, 20 parts of POE-156 resin, 3 parts of Ricon 181 resin, 0.9 parts of tert-amyl peroxy-2-ethylhexyl carbonate, 0.7 parts of trimethylolpropane triacrylate, 0.2 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0142] The preparation method of the EPE three-layer co-extruded film of this embodiment is the same as that of Embodiment 1.

[0143] Example 7

[0144] This embodiment provides an EPE three-layer co-extruded film, comprising a first EVA layer, a POE layer and a second EVA layer arranged in sequence, wherein the thickness of the first EVA layer and the second EVA layer are both 150 μm, and the thickness of the POE layer is 250 μm.

[0145] The first EVA layer and the second EVA layer both include the following components in parts by weight: 70 parts of EVA resin, 15 parts of EVA-156 resin, 10 parts of EVA-157 resin, 5 parts of EVA-150 resin, 3 parts of 4045 ethylene propylene rubber, 0.5 parts of tert-amyl peroxide-2-ethylhexyl carbonate, 0.5 parts of trimethylolpropane triacrylate, 0.4 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0146] The POE layer includes the following components in parts by weight: 40 parts of POE-130 resin, 20 parts of POE-142 resin, 40 parts of POE-156 resin, 3 parts of Ricon 181 resin, 0.9 parts of tert-amyl peroxy-2-ethylhexyl carbonate, 0.7 parts of trimethylolpropane triacrylate, 0.2 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0147] The preparation method of the EPE three-layer co-extruded film of this embodiment is the same as that of Embodiment 1.

[0148] Example 8

[0149] This embodiment refers to the EPE three-layer co-extruded film and preparation method thereof of Embodiment 4, the only difference being that the compositions of the first EVA layer and the second EVA layer are different.

[0150] The first EVA layer and the second EVA layer of this embodiment both include the following components in parts by weight: 70 parts of EVA resin, 22.5 parts of EVA-156 resin, 7.5 parts of EVA-150 resin, 3 parts of 4045 EPDM rubber, 0.5 parts of tert-amyl peroxide-2-ethylhexyl carbonate, 0.5 parts of trimethylolpropane triacrylate, 0.4 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0151] Example 9

[0152] This embodiment refers to the EPE three-layer co-extruded film and its preparation method of Example 4, the only difference is that the composition of the POE layer is different.

[0153] The POE layer of this embodiment includes the following components in parts by weight: 71 parts of POE-130 resin, 29 parts of POE-156 resin, 3 parts of Ricon 181 resin, 0.9 parts of tert-amyl peroxide-2-ethylhexyl carbonate, 0.7 parts of trimethylolpropane triacrylate, 0.2 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0154] Example 10

[0155] This embodiment refers to the EPE three-layer co-extruded film and preparation method thereof of Example 4, with the only difference being that the thickness of the first EVA layer and the second EVA layer are both 200 μm, and the thickness of the POE layer is 150 μm.

[0156] Comparative Example 1

[0157] Comparative Example 1 refers to the EPE three-layer co-extruded film and preparation method thereof of Example 4, except that the compositions of the first EVA layer, the second EVA layer and the POE layer are different.

[0158] The first EVA layer and the second EVA layer of Comparative Example 1 both include the following components in parts by weight: 100 parts of EVA resin, 0.5 parts of tert-amyl peroxy-2-ethylhexyl carbonate, 0.5 parts of trimethylolpropane triacrylate, 0.4 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0159] The POE layer of Comparative Example 1 includes the following components in parts by weight: 100 parts of POE resin, 0.9 parts of tert-amyl peroxy-2-ethylhexyl carbonate, 0.7 parts of trimethylolpropane triacrylate, 0.2 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0160] Comparative Example 2

[0161] Comparative Example 2 refers to the EPE three-layer co-extruded film and its preparation method of Example 4, except that the compositions of the first EVA layer and the second EVA layer are different.

[0162] The first EVA layer and the second EVA layer of Comparative Example 2 both include the following components in parts by weight: 100 parts of EVA resin, 0.5 parts of tert-amyl peroxide-2-ethylhexyl carbonate, 0.5 parts of trimethylolpropane triacrylate, 0.4 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0163] Comparative Example 3

[0164] Comparative Example 3 refers to the EPE three-layer co-extruded film and its preparation method of Example 4, except that the composition of the POE layer is different.

[0165] The POE layer of Comparative Example 3 includes the following components in parts by weight: 100 parts of POE resin, 0.9 parts of tert-amyl peroxy-2-ethylhexyl carbonate, 0.7 parts of trimethylolpropane triacrylate, 0.2 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0166] Comparative Example 4

[0167] Comparative Example 4 refers to the EPE three-layer co-extruded film and preparation method thereof of Example 4, except that the compositions of the first EVA layer, the second EVA layer and the POE layer are different.

[0168] The first EVA layer and the second EVA layer of Comparative Example 4 both include the following components in parts by weight: 70 parts of EVA resin, 15 parts of EVA-156 resin, 10 parts of EVA-157 resin, 5 parts of EVA-150 resin, 0.5 parts of tert-amyl peroxide-2-ethylhexyl carbonate, 0.5 parts of trimethylolpropane triacrylate, 0.4 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0169] The POE layer of Comparative Example 4 includes the following components in parts by weight: 50 parts of POE-130 resin, 30 parts of POE-142 resin, 20 parts of POE-156 resin, 0.9 parts of tert-amyl peroxide-2-ethylhexyl carbonate, 0.7 parts of trimethylolpropane triacrylate, 0.2 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0170] Comparative Example 5

[0171] Comparative Example 5 refers to the EPE three-layer co-extruded film and its preparation method of Example 4, except that the compositions of the first EVA layer and the second EVA layer are different.

[0172] The first EVA layer and the second EVA layer of Comparative Example 5 both include the following components in parts by weight: 50 parts of EVA resin, 50 parts of EVA-150 resin, 3 parts of 4045 ethylene propylene rubber, 0.5 parts of tert-amyl peroxide-2-ethylhexyl carbonate, 0.5 parts of trimethylolpropane triacrylate, 0.4 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0173] Comparative Example 6

[0174] Comparative Example 6 refers to the EPE three-layer co-extruded film and its preparation method of Example 4, except that the composition of the POE layer is different.

[0175] The POE layer of Comparative Example 6 includes the following components in parts by weight: 100 parts of POE-156 resin, 3 parts of Ricon 181 resin, 0.9 parts of tert-amyl peroxy-2-ethylhexyl carbonate, 0.7 parts of trimethylolpropane triacrylate, 0.2 parts of 3-methacryloxypropyltrimethoxysilane, and 0.1 parts of antioxidant 1010.

[0176] Experimental example

[0177] In order to compare and illustrate the performance differences of different EPE three-layer co-extruded films, the EPE three-layer co-extruded films prepared in different embodiments and comparative examples were subjected to the following tests. The test results are shown in Table 2.

[0178] Preparation of film samples: Take the EPE three-layer co-extruded film prepared in the embodiment and the comparative example, put the film into a vacuum laminator according to the test method of GB / T 29848-2018, and laminate it at 145°C for 15 minutes to prepare the sample; the prepared film sample is subjected to the following test (1) and test (2).

[0179] (1) Cross-linking degree test: refer to the method in GB / T 29848-2018 "Ethylene-vinyl acetate copolymer (EVA) adhesive film for photovoltaic module encapsulation";

[0180] (2) Water vapor transmission rate test: refer to the method in GB / T 30412-2013 "Plastic film and sheeting - Determination of water vapor transmission rate - Humidity sensor method".

[0181] Sample preparation: Take the EPE three-layer co-extruded film prepared in the embodiment and the comparative example, put it into a vacuum laminator in the order of "tempered glass / film / backboard" according to the test method of GB / T29848-2018, and laminate it at 145°C for 15 minutes to prepare a single glass sample. The prepared sample is subjected to the following test (3), test (4), and test (5), and the adhesion test data is recorded. The appearance of the sample is observed to see whether it is delaminated from the glass and / or backboard, and whether the film itself is delaminated.

[0182] (3) High temperature and high humidity aging test: Test according to the test method provided in GB / T 29848-2018;

[0183] (4) UV aging resistance test: Tested according to the test method provided in GB / T 29848-2018;

[0184] (5) PCT aging test: The test is carried out in accordance with the test method provided in GB / T 29848-2018.

[0185] Table 2 Performance test results of different EPE three-layer co-extruded films

[0186]

[0187] From the above test results, it can be seen that the EPE three-layer co-extruded film of the embodiment of the present invention exhibits high adhesion performance, water barrier performance and excellent resistance to high temperature and high humidity aging, UV resistance and long-term heat and humidity aging. The EPE film of Comparative Example 1 did not add modified EVA and modified POE resins, and the performance of the EPE film was poor. In Comparative Examples 2 and 3, only the POE layer or the EVA layer was improved, and the improvement in the compatibility of the EVA layer and the POE layer in the EPE film was limited, and delamination was prone to occur during the aging process. No compatibilizer was added in Comparative Example 4, and the improvement in the aging resistance of the EPE film was limited. In Comparative Example 5, an excessive amount of modified EVA resin is added, and only a single modified EVA resin is used. The POE layer of Comparative Example 6 only uses a POE resin grafted with polybutadiene with a high vinyl content. The cross-linked network formed during the cross-linking process of the films of Comparative Example 5 and Comparative Example 6 is too dense, resulting in poor wettability of the film with glass or battery cells, and further poor adhesion and aging properties of the film.

[0188] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. EPE three-layer co-extruded film, characterized by: It includes a first EVA layer, a POE layer and a second EVA layer which are arranged in sequence; The first EVA layer and the second EVA layer each independently include the following components by weight: 50-85 parts of EVA resin, 15-45 parts of modified EVA resin, 1-5 parts of compatibilizer, 0.1-2 parts of crosslinking agent, 0.1-2 parts of auxiliary crosslinking agent, 0.1-2 parts of silane coupling agent and 0.01-1 parts of antioxidant; The POE layer comprises the following components by weight: 100 parts of modified POE resin, 1 to 5 parts of compatibilizer, 0.1 to 2 parts of crosslinking agent, 0.1 to 2 parts of auxiliary crosslinking agent, 0.1 to 2 parts of silane coupling agent and 0.01 to 1 part of antioxidant; The modified EVA resin comprises at least two EVA resins graft-modified by polybutadiene with different molecular weights; and the modified POE resin comprises at least two POE resins graft-modified by polybutadiene with different vinyl contents.

2. The EPE three-layer co-extruded film according to claim 1, characterized in that: Having at least one of the following characteristics: (1) Among the polybutadienes of different molecular weights, the molecular weight of the polybutadiene is 1400 to 8000 g / mol; (2) Among the polybutadienes with different vinyl contents, the vinyl content of the polybutadiene is 18% to 70%.

3. The EPE three-layer co-extruded film according to claim 1, characterized in that: The modified EVA resin includes a first modified EVA resin, a second modified EVA resin and a third modified EVA resin; the first modified EVA resin, the second modified EVA resin and the third modified EVA resin are respectively EVA resins grafted and modified with a first polybutadiene, a second polybutadiene and a third polybutadiene, the molecular weight of the first polybutadiene is 3800 to 4100 g / mol, the molecular weight of the second polybutadiene is 1800 to 2000 g / mol, and the molecular weight of the third polybutadiene is 1400 to 1600 g / mol.

4. The EPE three-layer co-extruded film according to claim 3, characterized in that: The modified EVA resin includes 5 to 15 parts by weight of a first modified EVA resin, 5 to 15 parts by weight of a second modified EVA resin, and 5 to 15 parts by weight of a third modified EVA resin; Preferably, the amounts of the first modified EVA resin, the second modified EVA resin and the third modified EVA resin are increased in sequence.

5. The EPE three-layer co-extruded film according to claim 1, characterized in that: The modified POE resin includes a first modified POE resin, a second modified POE resin and a third modified POE resin; the first modified POE resin, the second modified POE resin and the third modified POE resin are POE resins grafted and modified with a fourth polybutadiene, a fifth polybutadiene and a sixth polybutadiene, respectively; the vinyl content of the fourth polybutadiene is 65% to 70%, the vinyl content of the fifth polybutadiene is 50% to 60%, and the vinyl content of the sixth polybutadiene is 18% to 25%.

6. The EPE three-layer co-extruded film according to claim 5, characterized in that: The modified POE resin includes 10 to 40 parts by weight of a first modified POE resin, 20 to 40 parts by weight of a second modified POE resin, and 30 to 60 parts by weight of a third modified POE resin; Preferably, the amounts of the first modified POE resin, the second modified POE resin and the third modified POE resin are increased in sequence.

7. The EPE three-layer co-extruded film according to claim 1, characterized in that: The modified EVA resin is mainly prepared by extrusion granulation of EVA resin, peroxide initiator and polybutadiene in a mass ratio of 100:(0.01-0.5):(1-10); The modified POE resin is mainly prepared by extrusion granulation of POE resin, peroxide initiator and polybutadiene in a mass ratio of 100:(0.01-0.5):(1-10).

8. The EPE three-layer co-extruded film according to claim 1, characterized in that: The compatibilizer includes at least one of EPDM rubber, EPDM rubber and butadiene-styrene copolymer; Preferably, the butadiene-styrene copolymer has a vinyl content of 20% to 70% and a molecular weight of 3000 to 9000 g / mol.

9. The method for preparing EPE three-layer co-extruded film is characterized in that: The EPE three-layer co-extruded film is obtained by melt co-extruding the composition of the first EVA layer, the POE layer and the second EVA layer of the EPE three-layer co-extruded film according to any one of claims 1 to 8.

10. Use of the EPE three-layer co-extruded film according to any one of claims 1 to 8 in the preparation of photovoltaic modules.

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