The components for the wrapping film and the wrapping film itself, which includes those components.

Abstract

Invention details;

Description

Composition for encapsulating film and encapsulating film comprising the same

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 2022-0107467, filed August 26, 2022, the entire contents of which are incorporated herein by reference.

[0003]

[0004] Technology field

[0005] The present invention relates to a composition for a sealing film comprising an ethylene / alpha-olefin copolymer, a sealing film, and a solar cell module.

[0006]

[0007] As global environmental and energy problems become increasingly serious, solar cells are attracting attention as a means of generating energy without concerns about environmental pollution or depletion. When solar cells are used outdoors, such as on building roofs, they are generally used in the form of solar cell modules. When manufacturing solar cell modules, to obtain a crystalline solar cell module, the following layers are laminated in order: front glass / solar cell encapsulant / crystalline solar cell element / solar cell encapsulant / rear glass (or rear protection sheet). Typically, ethylene / vinyl acetate copolymers or ethylene / alpha-olefin copolymers, which have excellent transparency, flexibility, and adhesiveness, are used as the solar cell encapsulant.

[0008] A solar cell module is a package in which solar cell elements such as silicon, gallium-arsenide, and copper-indium-selenide are protected by an upper transparent protective layer and a lower substrate protective layer, and the solar cell elements and the protective layer are fixed with a sealant. Generally, the sealant for the solar cell elements in a solar cell module is manufactured by extruding an ethylene / alpha-olefin copolymer blended with an organic peroxide or silane coupling agent into a sheet shape, and the solar cell elements are sealed using the obtained sheet-shaped sealant, thereby manufacturing a solar cell module.

[0009] When manufacturing solar cell modules as described above, one approach to improving productivity is to increase the affinity between the various raw materials included in the encapsulant film composition and the ethylene / alpha-olefin copolymer, thereby enhancing absorbency. In particular, crosslinking agents and crosslinking aids, which are essential for the production of encapsulant films, are polar substances and thus inevitably exhibit low absorbency toward the non-polar ethylene / alpha-olefin copolymer. This has been identified as one of the factors causing reduced productivity.

[0010]

[0011] [Prior Art Literature]

[0012] [Patent Document]

[0013] (Patent Document 1) Japanese Patent Publication No. 2015-211189

[0014]

[0015] The purpose of the present invention is to shorten the impregnation time of an ethylene / alpha-olefin copolymer in the initial stage of manufacturing a sealing film by using a crosslinking agent, crosslinking assistant, etc. having high affinity with the ethylene / alpha-olefin copolymer.

[0016]

[0017] To solve the above problem, the present invention provides a composition for a sealing film, a sealing film, and a solar cell module.

[0018] (1) The present invention provides a composition for a sealing film, comprising an ethylene / alpha-olefin copolymer, an organic peroxide crosslinking agent, a crosslinking aid, and a silane coupling agent, wherein the crosslinking aid comprises a compound represented by the following chemical formula 1, and the organic peroxide crosslinking agent has a 1-hour half-life temperature of 115 to 130°C.

[0019] [Chemical Formula 1]

[0020]

[0021] In the above chemical formula 1,

[0022] n is an integer from 2 to 6.

[0023] (2) The present invention provides a composition for a sealing film, wherein in the above (1), the organic peroxide crosslinking agent is at least one selected from the group consisting of t-butylperoxy 2-ethylhexyl carbonate, t-amylperoxy 2-ethylhexyl carbonate, 1,1-di(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-di(t-butylperoxy)-cyclohexane, 2,2-di(t-amylperoxy)-butane, 2,2-di(t-butylperoxy)-butane, n-butyl-4,4-di(t-butylperoxy)valerate, polyether poly(t-butyl peroxycarbonate), t-amylperoxy 3,5,5-trimethylhexanoate, t-butyl peroxyacetate, and t-butyl peroxybenzoate.

[0024] (3) The present invention provides a composition for a sealing film, wherein the organic peroxide crosslinking agent is 0.1 to 3.0 parts by weight based on 100 parts by weight of the ethylene / alpha-olefin copolymer in the above (1) or (2).

[0025] (4) The present invention provides a composition for a sealing film, wherein the crosslinking agent is present in an amount of 0.1 to 3.0 parts by weight based on 100 parts by weight of an ethylene / alpha-olefin copolymer in any one of the above (1) to (3).

[0026] (5) The present invention provides a composition for a sealing film, wherein the silane coupling agent is present in an amount of 0.1 to 1.0 parts by weight based on 100 parts by weight of an ethylene / alpha-olefin copolymer in any one of the above (1) to (4).

[0027] (6) The present invention provides a composition for a sealing film, wherein the crosslinking agent further comprises an allyl group-containing compound in any one of the above (1) to (5).

[0028] (7) The present invention provides a composition for a sealing film, wherein, in the above (6), the allyl group-containing compound comprises at least one selected from the group consisting of triallyl isocyanurate, triallyl cyanurate, diallyl phthalate, diallyl fumarate, and diallyl maleate.

[0029] (8) The present invention provides a composition for a sealing film in which the molar ratio of the compound represented by the chemical formula 1 and the allyl group-containing compound is 1:0.1 to 1:10 in any one of the above (6) and (7).

[0030] (9) The present invention provides a composition for a sealing film, wherein in any one of the above (1) to (8), the alpha-olefin comprises at least one selected from the group consisting of propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-eicosene.

[0031] (10) The present invention provides a composition for a sealing film, wherein the alpha-olefin is contained in an amount of 0 to 99 mol% based on an ethylene / alpha-olefin copolymer in any one of (1) to (9).

[0032] (11) The present invention provides a sealing film comprising a composition for a sealing film of any one of the above (1) to (10).

[0033] (12) The present invention provides a solar cell module including the sealing film of (11).

[0034]

[0035] When manufacturing a sealing film using the composition for a sealing film according to the present invention, the impregnation time of the ethylene / alpha-olefin copolymer can be shortened, thereby improving the economic efficiency of the sealing film production process. In addition, the composition for a sealing film manufactured using the present invention exhibits excellent crosslinking properties.

[0036]

[0037] Hereinafter, the present invention will be described in more detail to help understand the present invention.

[0038] The terms or words used in the description and claims of the present invention should not be interpreted as limited to their usual or dictionary meanings, and should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0039]

[0040] <Composition for packaging film>

[0041] The composition for a sealing film of the present invention comprises (a) an ethylene / alpha-olefin copolymer, (b) an organic peroxide crosslinking agent, (c) a crosslinking agent, and (d) a silane coupling agent, wherein the crosslinking agent comprises a compound represented by the following chemical formula 1.

[0042]

[0043] Below, each component is explained in detail.

[0044]

[0045] (a) ethylene / alpha-olefin copolymer

[0046] The composition for a sealing film of the present invention comprises an ethylene / alpha-olefin copolymer. The ethylene / alpha-olefin copolymer is prepared by copolymerizing ethylene and an alpha-olefin monomer, wherein the alpha-olefin, which refers to a portion derived from the alpha-olefin monomer in the copolymer, is an alpha-olefin having 4 to 20 carbon atoms, specifically, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, or 1-eicosene, and may be one kind alone or a mixture of two or more kinds thereof.

[0047] Among these, the alpha-olefin may be 1-butene, 1-hexene or 1-octene, and preferably 1-butene, 1-octene or a combination thereof.

[0048] In addition, the content of alpha-olefin in the ethylene / alpha-olefin copolymer may be appropriately selected within a range that satisfies the above-mentioned physical property requirements, and specifically may be 0 to 99 mol%, or 10 to 50 mol%, but is not limited thereto.

[0049] In the present invention, the method or obtaining route for preparing the ethylene / alpha-olefin copolymer is not limited, and a person skilled in the art can select and use an appropriate one considering the properties and purpose of the composition for a sealing film.

[0050]

[0051] (b) organic peroxide crosslinking agent

[0052] The composition for a sealing film of the present invention comprises an organic peroxide crosslinking agent. The organic peroxide crosslinking agent can serve as a radical initiator in the step of preparing a silane-modified resin composition, and can initiate a reaction in which an unsaturated silane compound is grafted onto the resin composition. In addition, by forming crosslinking bonds between the silane-modified resin compositions or between the silane-modified resin composition and the unmodified resin composition in the step of laminating during the manufacture of an optoelectronic device, the heat resistance durability of a final product, such as a sealing sheet, can be improved.

[0053] In particular, the encapsulating material for solar cells may include an organic peroxide as a crosslinking agent, and the organic peroxide serves to improve the weather resistance of the encapsulating material for solar cells.

[0054]

[0055] The organic peroxide crosslinking agent may have a 1-hour half-life temperature of 115 to 130°C.

[0056] The above "1-hour half-life temperature" refers to the temperature at which the half-life of the cross-linking agent becomes 1 hour. Depending on the 1-hour half-life temperature, the temperature at which the radical initiation reaction efficiently occurs varies. Therefore, when an organic peroxide cross-linking agent having a 1-hour half-life temperature within the above-mentioned range is used, the radical initiation reaction, i.e., the cross-linking reaction, can effectively proceed at the lamination process temperature for manufacturing an optoelectronic device.

[0057]

[0058] Specifically, the organic peroxide crosslinking agent may include, but is not limited to, at least one selected from the group consisting of t-butylperoxy 2-ethylhexyl carbonate (TBEC), t-amylperoxy 2-ethylhexyl carbonate (TAEC), 1,1-di(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-di(t-butylperoxy)-cyclohexane, 2,2-di(t-amylperoxy)-butane, 2,2-di(t-butylperoxy)-butane, n-butyl-4,4-di(t-butylperoxy)valerate, polyether poly(t-butyl peroxycarbonate), t-amylperoxy 3,5,5-trimethylhexanoate, t-butyl peroxyacetate, and t-butyl peroxybenzoate.

[0059]

[0060] When the 1-hour half-life temperature of the organic peroxide crosslinking agent is within the above range, the radical decomposition rate of the crosslinking agent during the crosslinking process is no faster than the crosslinking rate of the ethylene / alpha-olefin copolymer, thereby achieving the desired degree of crosslinking. Furthermore, under typical crosslinking conditions (140-150°C), the slow radical decomposition rate of the crosslinking agent can be suppressed from slowing down the crosslinking rate.

[0061]

[0062] The organic peroxide crosslinking agent may be included in an amount of 0.1 to 3.0 parts by weight, 0.1 to 2.0 parts by weight, or 0.5 to 1.5 parts by weight based on 100 parts by weight of the ethylene / alpha-olefin copolymer. When the organic peroxide crosslinking agent is included in the above range, the effect of improving heat resistance characteristics is sufficiently exhibited, and the formability of the sealing film is also excellent, so that no process restrictions or deterioration of the physical properties of the sealing material may occur.

[0063]

[0064] (c) Cross-linking preparation

[0065] The composition for a sealing film of the present invention comprises a crosslinking agent, wherein the crosslinking agent comprises a compound represented by the following chemical formula 1.

[0066] [Chemical Formula 1]

[0067]

[0068] In the above chemical formula 1,

[0069] n is an integer from 2 to 6.

[0070]

[0071] Specifically, the compound represented by the above chemical formula 1 can be selected from the following compounds.

[0072] [Chemical Formula 1-1]

[0073]

[0074] [Chemical Formula 1-2]

[0075]

[0076] The crosslinking agent used in the present invention, unlike crosslinking agents used in the past such as triallyl isocyanurate, is nonpolar and has excellent affinity for ethylene / alpha-olefin copolymers, enabling rapid impregnation.

[0077] In addition, the cyclohexane and carboxylate functional groups located at the center of the crosslinking agent structure can firmly fix the polymer chains, thereby achieving excellent crosslinking.

[0078]

[0079] In this way, by including the crosslinking agent together with the organic peroxide crosslinking agent described above in the composition for a sealing film, the absorption rate of the crosslinking agent and the crosslinking agent described above in the composition for a sealing film is greatly improved, and at the same time, the degree of crosslinking is further increased, thereby greatly improving the production economy while maintaining the heat resistance and durability of the final product, such as a sealing film.

[0080]

[0081] In the present invention, the composition for the encapsulating film may further include an allyl group-containing compound as a crosslinking agent.

[0082] The above allyl group-containing compound may include at least one selected from the group consisting of triallyl isocyanurate, triallyl cyanurate, diallyl phthalate, diallyl fumarate, and diallyl maleate.

[0083] Here, the molar ratio of the compound represented by the above chemical formula 1 and the allyl group-containing compound may be 1:0.1 to 1:10, specifically 1:0.2 to 1:5, and more specifically 1:0.3 to 1:4.

[0084] Within the above range, the impregnation time of the ethylene / alpha-olefin copolymer can be shortened while also increasing the crosslinking degree of the composition for the encapsulating film.

[0085]

[0086] In addition, the crosslinking agent may be present in an amount of 0.1 to 3.0 parts by weight, specifically, 0.1 to 2.0 parts by weight, or 0.25 to 1.50 parts by weight, based on 100 parts by weight of the ethylene / alpha-olefin copolymer.

[0087] By including a crosslinking agent in the above range, the crosslinking agent impregnation time of the ethylene / alpha-olefin copolymer can be shortened while maintaining a high degree of crosslinking of the composition for a sealing film.

[0088]

[0089] (d) silane coupling agent

[0090] The composition for a sealing film of the present invention includes a silane coupling agent, which can serve to improve the adhesion between the sealing film and the solar cell.

[0091] As the above silane coupling agent, for example, at least one selected from the group consisting of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane (MEMO) may be used, but is not limited thereto.

[0092] The above silane coupling agent may be included in an amount of 0.1 to 1.0 parts by weight, or 0.1 to 0.4 parts by weight, based on 100 parts by weight of the ethylene / alpha-olefin copolymer.

[0093]

[0094] When the content of the silane coupling agent is within the above range, the adhesive strength with glass is excellent during the manufacture of a solar cell module, thereby preventing long-term performance degradation of the module due to moisture penetration.

[0095]

[0096] In addition, the composition for a sealing film of the present invention may additionally include at least one selected from the group consisting of an unsaturated silane compound, an amino silane compound, a light stabilizer, a UV absorber, and a heat stabilizer.

[0097] The above unsaturated silane compound may be grafted onto a main chain including a polymerization unit of a monomer of the copolymer of the present invention in the presence of a radical initiator or the like, and may be included in a polymerized form in a silane-modified resin composition or an amino-silane-modified resin composition.

[0098] The above unsaturated silane compound may be vinyltrimethoxy silane, vinyltriethoxy silane, vinyltripropoxy silane, vinyltriisopropoxy silane, vinyltributoxy silane, vinyltripentoxy silane, vinyltriphenoxy silane, or vinyltriacetoxy silane, and as an example, vinyltrimethoxy silane or vinyltriethoxy silane may be used, but is not limited thereto.

[0099]

[0100] In addition, the amino silane compound acts as a catalyst that promotes a hydrolysis reaction that converts a reactive functional group, such as an alkoxy group of an unsaturated silane compound grafted onto the main chain of the copolymer, such as vinyltriethoxysilane, into a hydroxyl group in the grafting modification step of the ethylene / alpha-olefin copolymer, thereby further improving the adhesive strength with the back sheet composed of the upper and lower glass substrates or fluororesin. In addition, at the same time, the amino silane compound also participates as a reactant in the direct copolymerization reaction, thereby providing a moiety having an amine functional group to the amino silane-modified resin composition.

[0101] The above amino silane compound is a silane compound containing an amine group, and is not particularly limited as long as it is a primary amine or a secondary amine. For example, amino silane compounds that can be used include aminotrialkoxysilanes, aminodialkoxysilanes, etc., and examples thereof include 3-aminopropyltrimethoxysilane (APTMS), 3-aminopropyltriethoxysilane (APTES), bis[(3-triethoxysilyl)propyl]amine, bis[(3-trimethoxysilyl)propyl]amine, 3-aminopropylmethyldiethoxysilane, 3-aminopropylmethyldimethoxysilane, N-[3-(trimethoxysilyl)propyl]ethylenediamine (DAS), aminoethylaminopropyltriethoxysilane, aminoethylaminopropylmethyldimethoxysilane, aminoethylaminopropylmethyldiethoxysilane, aminoethylaminomethyltriethoxysilane, At least one selected from the group consisting of aminoethylaminomethylmethyldiethoxysilane, diethylenetriaminopropyltrimethoxysilane, diethylenetriaminopropyltriethoxysilane, diethylenetriaminopropylmethyldimethoxysilane, diethyleneaminomethylmethyldiethoxysilane, (N-phenylamino)methyltrimethoxysilane, (N-phenylamino)methyltriethoxysilane, (N-phenylamino)methylmethyldimethoxysilane, (N-phenylamino)methylmethyldiethoxysilane, 3-(N-phenylamino)propyltrimethoxysilane, 3-(N-phenylamino)propyltriethoxysilane, 3-(N-phenylamino)propylmethyldimethoxysilane, 3-(N-phenylamino)propylmethyldiethoxysilane, and N-(N-butyl)-3-aminopropyltrimethoxysilane. The above amino silane compounds may be used alone or in mixtures.

[0102]

[0103] The above-mentioned light stabilizer may prevent photooxidation by capturing the active species that initiates photodegradation of the resin, depending on the intended use of the composition. The type of light stabilizer that can be used is not particularly limited, and for example, known compounds such as hindered amine compounds or hindered piperidine compounds can be used.

[0104] The above UV absorber can, depending on the use of the composition, absorb ultraviolet rays from sunlight or the like, convert them into harmless heat energy within the molecule, and prevent the active species that initiates photodegradation in the resin composition from being excited. The specific type of UV absorber that can be used is not particularly limited, and for example, one type or a mixture of two or more types of inorganic UV absorbers such as benzophenone-based, benzotriazole-based, acrylonitrile-based, metal complex-based, hindered amine-based, ultrafine titanium oxide-based, or ultrafine zinc oxide-based can be used.

[0105] In addition, examples of the heat stabilizer include phosphorus-based heat stabilizers such as tris(2,4-di-tert-butylphenyl)phosphite, bis[2,4-bis(1,1-dimethylethyl)-6-methylphenyl]ethyl ester phosphorous acid, tetrakis(2,4-di-tert-butylphenyl)[1,1-biphenyl]-4,4'-diylbisphosphonate, and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite; lactone-based heat stabilizers such as the reaction product of 8-hydroxy-5,7-di-tert-butyl-furan-2-one and o-xylene, and one or two or more of the above may be used.

[0106] The content of the above-mentioned light stabilizer, UV absorber, and heat stabilizer is not particularly limited. That is, the content of the above-mentioned additives can be appropriately selected in consideration of the intended use of the resin composition, the shape or density of the additives, etc., and can typically be appropriately adjusted within the range of 0.01 to 5 parts by weight based on 100 parts by weight of the total solid content of the composition for the sealant film.

[0107]

[0108] <Encapsulating film and solar cell module>

[0109] In addition, the present invention provides a sealing film comprising the composition for the sealing film.

[0110] The encapsulating film of the present invention can be manufactured by molding the encapsulating film composition into a film or sheet shape. The molding method is not particularly limited, and for example, it can be manufactured by forming a sheet or film using a conventional process such as a T-die process or extrusion. For example, the manufacturing of the encapsulating film can be performed in situ using a device in which the manufacturing of a modified resin composition using the encapsulating film composition and the film or sheet forming process are interconnected.

[0111] The thickness of the above-mentioned encapsulating film can be adjusted to about 10 to 2,000 ㎛, or about 100 to 1,250 ㎛, taking into consideration the support efficiency and breakage possibility of the element in the optoelectronic device, weight reduction and workability of the device, etc., and can be changed depending on the specific use.

[0112]

[0113] In addition, the present invention provides a solar cell module comprising the encapsulant film. In the present invention, the solar cell module may have a configuration in which solar cell cells arranged in series or parallel are spaced apart by the encapsulant film of the present invention, a glass surface is arranged on the side that receives sunlight, and the back surface is protected by a back sheet, but is not limited thereto, and various types and shapes of solar cell modules manufactured including the encapsulant film in the relevant technical field can all be applied to the present invention.

[0114] The above glass surface may be made of tempered glass to protect the solar cell from external impact and prevent breakage, and may be made of low iron tempered glass to prevent reflection of sunlight and increase the transmittance of sunlight, but is not limited thereto.

[0115] The above backsheet is a weather-resistant film that protects the back surface of the solar cell module from the outside, and includes, but is not limited to, a fluorine-based resin sheet, a metal plate or metal foil such as aluminum, a cyclic olefin-based resin sheet, a polycarbonate-based resin sheet, a poly(meth)acrylic-based resin sheet, a polyamide-based resin sheet, a polyester-based resin sheet, and a composite sheet in which a weather-resistant film and a barrier film are laminated.

[0116] In addition, the solar cell module of the present invention can be manufactured without limitation according to a method known in the art, except that it includes the aforementioned encapsulant film.

[0117] The solar cell module of the present invention is manufactured using a sealing film having excellent volume resistance, and can prevent electrons within the solar cell module from moving through the sealing film and current from leaking out to the outside, thereby significantly suppressing the PID (Potential Induced Degradation) phenomenon in which insulation deteriorates, leakage current occurs, and module output rapidly decreases.

[0118]

[0119] Example

[0120] Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are intended to illustrate the present invention and are not intended to limit the scope of the present invention solely to these examples.

[0121]

[0122] Example 1

[0123] LG Chemical's LF675 (ethylene / 1-butene copolymer, density 0.877 g / cc, MI 14.0) was used as an ethylene / alpha-olefin copolymer.

[0124] After adding TBEC (t-butylperoxy 2-ethylhexyl carbonate) as a crosslinking agent, 2.5 g (0.5 phr) of DAHX (diallyl 1,4-cyclohexanedicarboxylate), a compound represented by the following chemical formula 1-1, as a crosslinking aid, and MEMO (3-(trimethoxysilyl)propyl methacrylate) as a silane coupling agent to an ethylene / alpha-olefin copolymer pellet resin, impregnation was performed.

[0125] The impregnation process was performed using a Haake mixer. While stirring at 40 rpm and a temperature of 41.5°C, the change in torque value over time was observed, and impregnation was terminated when the torque value increased rapidly. Before the crosslinking agent is absorbed into the ethylene / alpha-olefin copolymer, it acts as a lubricant, maintaining a low torque value. However, once the crosslinking agent is fully absorbed, the torque value increases. Therefore, the point at which the torque value rapidly increases was set as the impregnation completion time.

[0126]

[0127] Examples 2 to 5, Comparative Examples 1 to 8

[0128] A sealing film was manufactured in the same manner as in Example 1, except that the type and content of the crosslinking agent and crosslinking agent were changed as shown in Table 1 below.

[0129]

[0130] Crosslinking agentCrosslinking agent typeCrosslinking agent content (phr)Example 1TBECDAHX0.5Example 2TBECDAHX0.25Example 3TBECDAHX+TAIC0.375:0.125Example 4TAECDAHX0.25Example 5TAECDAHX+TAIC0.375:0.125Comparative Example 1TBECTAIC0.5Comparative Example 2TBEC1,6-bis(acryloyloxy)hexane0.5Comparative Example 3TBECpentaerythritol tetraacrylate0.5Comparative Example 4TBECtrimethylolpropane triacrylate0.5Comparative Example 5TBECtriallyl citrate0.5Comparative Example 61,1-di(t-amylperoxy)cyclohexaneDAHX0.5Comparative Example 7t-amylperoxy 2-Ethylhexanoate DAHX0.5 Comparative Example 8 Use XDAHX0.5

[0131] * TBEC: t-butylperoxy 2-ethylhexyl carbonate

[0132]

[0133] * TAEC: t-Amylperoxy 2-ethylhexyl carbonate

[0134]

[0135] * DAHX: Diallyl 1,4-cyclohexanedicarboxylate

[0136]

[0137] * TAIC: Triallyl isocyanurate

[0138]

[0139] Crosslinking agent 1 hour half-life temperature (℃) TBEC121 TAEC117 1,1-di(t-amylperoxy)cyclohexane 112 t-amylperoxy 2-ethylhexanoate 92

[0140] Experimental Example 1

[0141] (1) Impregnation completion time

[0142] As described in Example 1, the time at which the torque value rapidly increases was taken as the impregnation completion time, and the time from the start of stirring to the completion of impregnation was measured.

[0143]

[0144] (2) Cross-linking degree (%)

[0145] Crosslinking evaluation was conducted based on the CPIA (China Photovoltaic Industry Association) standards and ASTM D2765. The encapsulating film manufactured above was cut into 10 cm × 10 cm pieces, and crosslinked specimens were obtained by vacuum lamination at 150°C for 20 minutes (5 minutes of vacuum / 1 minute of pressurization / 14 minutes of continuous pressure).

[0146] The cross-linked specimens were cut into 2 mm × 2 mm sizes, weighed at 0.5 g each in a 200 mesh wire cage, and subjected to dissolution treatment under xylene reflux for 5 hours. Afterwards, the specimens were dried in a vacuum oven, and the weights before and after reflux were compared to measure the degree of cross-linking of each specimen.

[0147]

[0148] Impregnation completion time (min)Crosslinking degree (%)Example 12274Example 21370Example 33076Example 41975Example 52778Comparative example 16077Comparative example 24060Comparative example 3>60UntestedComparative example 4>60UntestedComparative example 5>60UntestedComparative example 61763Comparative example 71516Comparative example 8100

[0149] As shown in the results in Table 3 above, it was confirmed that the impregnation completion time was shortened compared to Comparative Examples 1 to 5, which used TAIC, which does not correspond to the compound represented by Chemical Formula 1, as a crosslinking agent. In addition, the results of the crosslinking evaluation experiment are as follows. Here, Comparative Examples 3 to 5, in which the impregnation completion time was found to be much higher than that of Comparative Example 1, were excluded from the crosslinking evaluation.

[0150] In Comparative Examples 6 and 7, which used organic peroxide crosslinking agents having a 1-hour half-life temperature of 115 to 130°C but lower than 115°C, the degree of crosslinking was lower than that of the examples, and in particular, when compared with Example 1 in which the same type and content of crosslinking agent was used, it was clearly confirmed that the degree of crosslinking varied depending on the difference in the type of crosslinking agent. Meanwhile, Comparative Example 8 was a case in which an organic peroxide crosslinking agent having a 1-hour half-life temperature of 115 to 130°C was not used, and it was confirmed that crosslinking did not proceed at all when only DAHX was used.

[0151]

[0152] Experimental Example 2

[0153] (1) Volume resistance

[0154] The volume resistivity of the crosslinked film (thickness 0.6 mm) manufactured for the above crosslinking evaluation was measured using KEITHLEY 8009 RESISTIVITY TEST FIXTURE. The volume resistivity was measured for 600 seconds under a voltage of 1000 V, and the result was used.

[0155] Volume resistivity (Ω·cm) Example 13.7 × 10 16 Example 22.6 × 10 16 Example 33.3 × 10 16 Example 44.6 × 10 16 Example 53.7 × 10 16 Comparative example 12.3 × 10 16 Comparative example 28.5 × 10 16 Comparative Example 3 Untested Comparative Example 4 Untested Comparative Example 5 Untested Comparative Example 63.0 × 10 16 Comparative example 74.1 × 10 16 Comparative example 84.0 × 10 16

[0156] As shown in Table 4 above, the composition for a sealing film according to the present invention has improved cross-linking while shortening the impregnation completion time, and at the same time, in order to exhibit sufficient insulating effect for use as a composition for a sealing film, the volume resistivity must be at least 1.0 × 10 16 This should be done, and it was found that in all examples, the volume resistance was also implemented at an excellent level.

Claims

DEPCT681. Composition for an encapsulation film consisting of an ethylene / alpha-olefin copolymer, an organic peroxide crosslinker, a crosslinking agent, and a silane coupling agent, in which the crosslinking agent is composed of a compound represented by the following Formula 1, and the organic peroxide crosslinker has a half-life of one hour at 115 to 130 °C: [Formula 1] (chemical formula). In Formula 1, n is an integer 2 to 6.

2. Composition for an encapsulation film according to claim 1, in which the organic peroxide crosslinker is 10 ... One or more selected samples were chosen from a group comprising t-butyl peroxy2-ethylhexyl carbonate, t-emyl peroxy2-ethylhexyl carbonate, 1,1-di(t-butyl peroxy)-3,3,5-trimethylcyclohexane, 1,1-di(t-butyl peroxy)-cyclohexane, 2,2-di(t-emyl peroxy)-butane, 2,2-di(t-butyl peroxy)-butane, n-butyl-4,4-di(t-butyl peroxy)valate, polyether poly(t-butyl peroxycarbonate), t-emyl peroxy3,5,5-trimethylhexanoate, t-butyl peroxy acetate, and t-butyl peroxybenzoate 3.The composition for the encapsulation film under claim I, where the organic peroxide crosslinking agent is 0.1 to 3.0 parts by weight on a basis of 100 parts by weight of ethylene / alpha-olefin copolymer.

4. The composition for the encapsulation film under claim I, where the crosslinking agent is 0.1 to 3.0 parts by weight on a basis of 100 parts by weight of ethylene / alpha-olefin copolymer.

5. The composition for the encapsulation film under claim I, where the silane coupling agent is 0.1 to 1.0 parts.

6. The composition for the encapsulation film under claim 1, in which the crosslinking agent is additionally incorporated with an allyl-containing compound.

7. The composition for the encapsulation film under claim 6, in which the allyl-containing compound is incorporated with one or more of the selected compounds from the group consisting of triallyl isocyanurate, triallyl cyanurate, diallyl phthalate, diallyl fumarate and diallyl malate. 8.Encapsulation film composition under claim 6 where the molar ratio of the compound represented by formula 1 to the compound containing allyl is 1:0.1 to 1:

109. Encapsulation film composition under claim 1 where the alpha-olefin is composed of one or more elements selected from the group consisting of propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undexene, 1-Dodecine, 1-Tetradecine, 1-Hexadecine, and 1-Eicosine.

10. Components for encapsulation films under claim 1 in which alpha-olefins are incorporated from 0 to 99% by mass on an ethylene / alpha-olefin copolymer basis.

11. Encapsulation films incorporating any one of the components for encapsulation films under claims 1 through 10.

12. Solar cell modules incorporating encapsulation films under claim 11.