Polyolefin composition

Abstract

The present invention relates to a polyolefin composition. The polyolefin composition according to the present invention includes a modified polyolefin containing a vinyl silane group, and thus can improve the degree of crosslinking. An encapsulant film manufactured using the polyolefin composition according to the present invention can exhibit an improved degree of crosslinking while maintaining optical properties and insulating properties.

Description

polyolefin composition

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0071568, filed May 31, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a polyolefin composition.

[0005]

[0006] Polyolefin elastomer (POE) is attracting attention as a solar cell encapsulating material due to its superior insulation and moisture barrier properties compared to EVA (Ethylene Vinyl Acetate).

[0007] However, POE encapsulants have a lower cross-linking degree than EVA, which can lead to bubble formation and reduced bonding stability during module manufacturing. Furthermore, in the case of EVA-POE-EVA three-layer encapsulants, the market for which has recently been rapidly expanding, problems due to the low cross-linking degree, such as bubble formation and delamination between layers, are becoming more acute due to differences in cross-linking speed and degree between EVA and POE.

[0008] Therefore, in order to solve the above problems, attempts are being made to improve the stability of module manufacturing by improving the cross-linking degree of POE encapsulating material.

[0009]

[0010] The purpose of the present invention is to provide a polyolefin composition having improved crosslinking degree while maintaining optical properties and insulating properties.

[0011]

[0012] 1. The present invention provides a polyolefin composition comprising a modified polyolefin containing a vinyl silane group.

[0013] 2. In the present invention, in the above 1, the modified polyolefin is immersed in acetone at 60°C for 12 hours, washed, and then dissolved in a TCE-d2 solvent. 1 A polyolefin composition is provided in which, when analyzed by H NMR (373K), the content of terminal double bonds detected at 5.7 to 6.3 ppm among peaks originating from a modified portion in the modified polyolefin is 0.001 or more and 1 or less per 1000 total carbon atoms.

[0014] 3. The present invention provides a polyolefin composition according to 1 or 2 above, wherein the vinyl silane group is derived from a silane compound containing two or more vinyl groups.

[0015] 4. The present invention provides a polyolefin composition in any one of the above 1 to 3, wherein the silane compound is selected from the group consisting of tris(vinyldimethylsiloxy)methylsilane, tris(vinyldimethylsiloxy)phenylsilane, 1,3,5-trivinyl-1,1,3,5,5-pentamethyltrisiloxane, 2,4,6-trimethyl-2,4,6-trivinylcyclotrisiloxane, tetravinylsilane, and 1,3-divinyltetramethyldisiloxane.

[0016] 5. The present invention provides a polyolefin composition according to any one of 1 to 4 above, wherein the polyolefin is a copolymer of ethylene and an alpha-olefin comonomer.

[0017] 6. The present invention provides a polyolefin composition according to any one of 1 to 5 above, wherein the alpha-olefin comonomer is an alpha-olefin comonomer having 3 to 12 carbon atoms.

[0018] 7. The present invention provides a polyolefin composition comprising at least one selected from the group consisting of 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-eicosene, norbornene, norbornadiene, ethylidenenorbornene, phenylnorbornene, vinylnorbornene, dicyclopentadiene, 1,4-butadiene, 1,5-pentadiene, 1,6-hexadiene, styrene, alpha-methylstyrene, divinylbenzene, and 3-chloromethylstyrene, in any one of the above 1 to 6.

[0019] 8. The present invention provides a composition for a sealing film comprising any one of the polyolefin compositions 1 to 7 above.

[0020] 9. The present invention provides a sealing film formed from the composition for sealing film of the above 8.

[0021] 10. The present invention provides a solar cell module including the sealing film of 9 above.

[0022]

[0023] The polyolefin composition of the present invention can exhibit improved crosslinking by including a modified polyolefin containing a vinyl silane group.

[0024] When manufacturing a sealing film using the polyolefin composition of the present invention as described above, improved crosslinking can be exhibited while maintaining optical properties and insulating properties, thereby increasing module manufacturing stability.

[0025]

[0026] Hereinafter, the present invention will be described in more detail to help understand the present invention.

[0027]

[0028] The present invention provides a polyolefin composition comprising a modified polyolefin containing a vinyl silane group.

[0029] Due to the vinyl silane group contained in the above-mentioned modified polyolefin, when a crosslinking agent, crosslinking assistant, etc. are added and reacted for the purpose of manufacturing a sealing film, etc. in the future, a higher crosslinking reaction can be induced, and a significant crosslinking degree improvement effect can be exhibited.

[0030] The above modified polyolefin is prepared by immersing the above modified polyolefin in acetone at 60°C for 12 hours, washing it, and then dissolving it in a TCE-d2 solvent. 1 When analyzing H NMR (373K), the content of terminal double bonds detected at 5.7 to 6.3 ppm among the peaks originating from the modified portion in the modified polyolefin may be 0.001 or more and 1 or less per 1000 total carbon atoms. The detected terminal double bond may be derived from the vinyl silane group.

[0031] When the above-mentioned modified polyolefin is analyzed by NMR and the content of terminal double bonds detected at 5.7 to 6.3 ppm is measured, some of the terminal double bonds contained in the original polyolefin (i.e., unmodified polyolefin) and the content of terminal double bonds originating from the modified portion may all be included. Among the terminal double bonds originating from the unmodified portion in the modified polyolefin, the hydrogen peak of one terminal double bond detected at 5.7 to 6.3 ppm can be calculated through the hydrogen peaks originating from two terminal double bonds detected in a range that does not overlap with the range of 5.7 to 6.3 ppm. Therefore, by analyzing the above-mentioned modified polyolefin by NMR and subtracting the hydrogen peak of one terminal double bond originating from the unmodified portion from the terminal double bond content detected at 5.7 to 6.3 ppm, the content of terminal double bonds originating from the modified portion in the modified polyolefin, detected at 5.7 to 6.3 ppm, can be obtained.

[0032] More specifically, in the NMR analysis, the content of terminal double bonds detected at 5.7 to 6.3 ppm among the peaks originating from the modified portion in the modified polyolefin may be 0.001 or more, 0.0015 or more, 0.002 or more, 0.0025 or more, 0.003 or more, 0.0035 or more, 0.004 or more, 0.0045 or more, 0.005 or more per 1000 total carbons, and may also be 1 or less, 0.98 or less, 0.96 or less, 0.94 or less, 0.92 or less, 0.9 or less, 0.88 or less, 0.86 or less, 0.84 or less. By introducing terminal double bonds that play a leading role in the crosslinking reaction into the modified polyolefin, the degree of crosslinking can be improved in a subsequent crosslinking reaction using a crosslinking agent, crosslinking assistant, etc. Accordingly, the polyolefin composition of the present invention can exhibit a significantly improved degree of crosslinking by including a modified polyolefin containing terminal double bonds within the above range.

[0033] The above vinyl silane group may be derived from a silane compound. The above modified polyolefin may be a conventional polyolefin modified through a chemical reaction (e.g., grafting, polymerization, etc.) with a silane compound so as to include a vinyl silane group. In this case, the silane compound may include two or more vinyl groups, and by including two or more vinyl groups, one or more unreacted vinyl groups may remain even after the chemical reaction with the polyolefin.

[0034] For example, the modified polyolefin of the present invention may be a polyolefin in which a silane compound is grafted onto the backbone of the polyolefin. The polyolefin may be a polyolefin in which no other compound is included or polymerized other than ethylene and alpha-olefin.

[0035] When grafting a silane compound onto the polyolefin backbone for the production of the above-mentioned modified polyolefin, a crosslinking agent may be added together and reacted. The addition of the crosslinking agent serves to initiate the grafting reaction of the silane compound, thereby enabling more effective grafting of the silane compound onto the polyolefin backbone. The crosslinking agent may be, for example, one or two or more selected from the group consisting of organic peroxides, hydroperoxides, and azo compounds. Specifically, 2,5-bis(t-butylperoxy)-2.5-dimethylhexane, t-buphylcumyl peroxide, di-t-butyl peroxide, di-cumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne, bis-3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, benzoyl peroxide, o-methylbenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, diacyl peroxides; It may be at least one selected from the group consisting of compounds such as t-butylperoxy isobutyrate, t-butylperoxy acetate, t-butylperoxy-2-ethylhexylcarbonate (TBEC), t-butylperoxy-2-ethylhexanoate, t-butylperoxy pivalate, t-butylperoxy octoate, t-butylperoxyisopropyl carbonate, t-butylperoxybenzoate, di-t-butylperoxyphthalate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, and 2,5-dimethyl-2,5-di(benzoylperoxy)-3-hexyne. More specifically, it may be 2,5-bis(t-butylperoxy)-2.5-dimethylhexane, which can be manufactured and used or a commercially available product (e.g., Luperox 101) can be purchased and used.

[0036] The above silane compound may contain two or more vinyl groups. By grafting a silane compound containing two or more vinyl groups onto the backbone of a polyolefin, vinyl groups can remain in the modified polyolefin obtained after grafting the silane compound. Due to the remaining vinyl groups, the crosslinking degree can be improved when the polyolefin is later applied to a sealing film or the like.

[0037] Additionally, the silane compound may contain a methyl group. When the silane compound contains a methyl group, the stability of the modified polyolefin may be improved.

[0038] The above silane compound may be selected from the group consisting of, for example, tris(vinyldimethylsiloxy)methylsilane, tris(vinyldimethylsiloxy)phenylsilane, 1,3,5-trivinyl-1,1,3,5,5-pentamethyltrisiloxane, 2,4,6-trimethyl-2,4,6-trivinylcyclotrisiloxane, tetravinylsilane, and 1,3-divinyltetramethyldisiloxane.

[0039] In addition, the modified polyolefin is prepared by immersing the modified polyolefin in acetone at 60°C for 12 hours, washing it, and then dissolving it in a TCE-d2 solvent. 1 When analyzing H NMR (373K), the content of methyl groups detected at 0.0 to 0.4 ppm among the peaks originating from the modified portion in the modified polyolefin may be 15 or less per 1000 total carbons.

[0040] In this way, the modified polyolefin may include a methyl silane group, and the detected methyl group may be derived from the methyl silane group.

[0041] If the silane compound that is chemically reacted to allow the modified polyolefin to include a vinyl silane group includes a methyl silane group, the modified polyolefin may include a methyl silane group.

[0042] More specifically, in the above NMR analysis, the content of methyl groups detected at 0.0 to 0.4 ppm may be 0 or more, 0.03 or more, 0.05 or more, 0.07 or more, 0.09 or more, 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, 0.9 or more, 1 or more, 1.5 or more, 2 or more, 2.5 or more, 3 or more per 1000 total carbons, and may also be 15 or less, 14 or less, 13 or less, 12 or less, or 11 or less. VTMS (vinyltrimethoxysilane), which is commonly used in conventional reactive extrusion, has poor stability because it can undergo side reactions such as hydrolysis in the presence of moisture due to the inclusion of methoxy groups. On the other hand, the modified polyolefin contains methyl groups in the above range, so that such side reactions do not occur, and thus stability can be improved.

[0043] The above polyolefin may be a copolymer of ethylene and an alpha-olefin comonomer. The modified olefin of the present invention may also be modified based on the above polyolefin.

[0044] The above alpha-olefin comonomer may be specifically an alpha-olefin comonomer having 3 to 12 carbon atoms, and more specifically an alpha-olefin comonomer having 4 to 8 carbon atoms. For example, the alpha-olefin comonomer may be at least one selected from the group consisting of 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-eicosene, norbornene, norbornadiene, ethylidenenorbornene, phenylnorbornene, vinylnorbornene, dicyclopentadiene, 1,4-butadiene, 1,5-pentadiene, 1,6-hexadiene, styrene, alpha-methylstyrene, divinylbenzene, and 3-chloromethylstyrene, and a more specific example may be 1-butene, 1-octene, or a combination thereof.

[0045] The polyolefin composition of the present invention may contain only the modified polyolefin, or may contain an unmodified polyolefin together with the modified polyolefin. The unmodified polyolefin may be a copolymer of the above-mentioned ethylene and alpha-olefin comonomer.

[0046] When the polyolefin composition of the present invention includes both the modified polyolefin and the unmodified polyolefin, the modified polyolefin may be included in an amount of 1 wt% or more and 60 wt% or less based on the total weight of the entire polyolefin composition. More specifically, it may be included in an amount of 1 wt% or more, 2 wt% or more, 3 wt% or more, 4 wt% or more, or 5 wt% or more, and may also be included in an amount of 60 wt% or less, 59 wt% or less, 58 wt% or less, 57 wt% or less, 56 wt% or less, 55 wt% or less, 54 wt% or less, 53 wt% or less, 52 wt% or less, 51 wt% or less, or 50 wt% or less. When the modified polyolefin is included in an amount less than the above range, the effect of improving the crosslinking degree may be minimal.

[0047]

[0048] In addition, the present invention provides a composition for a sealing film comprising the above-described polyolefin composition.

[0049] The composition for the above-mentioned encapsulating film may further include, in addition to the polyolefin composition described above, at least one selected from the group consisting of a crosslinking agent, a crosslinking assistant, a silane coupling agent, a light stabilizer, a UV absorber, and a heat stabilizer.

[0050] The above crosslinking agent can improve the heat resistance durability of the encapsulating sheet by helping to form crosslinking bonds.

[0051] The above crosslinking agent may be, for example, one or two or more selected from the group consisting of organic peroxides, hydroperoxides, and azo compounds.

[0052] Specifically, dialkyl peroxides such as t-buphylcumyl peroxide, di-t-butyl peroxide, di-cumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne; hydroperoxides such as cumene hydroperoxide, diisopropyl benzene hydroperoxide, 2,5-dimethyl-2,5-di(hydroperoxy)hexane, t-butyl hydroperoxide; diacyl peroxides such as bis-3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, benzoyl peroxide, o-methylbenzoyl peroxide, and 2,4-dichlorobenzoyl peroxide; Peroxy esters such as t-butylperoxy isobutyrate, t-butylperoxy acetate, t-butylperoxy-2-ethylhexylcarbonate (TBEC), t-butylperoxy-2-ethylhexanoate, t-butylperoxy pivalate, t-butylperoxy octoate, t-butylperoxyisopropyl carbonate, t-butylperoxybenzoate, di-t-butylperoxyphthalate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dimethyl-2,5-di(benzoylperoxy)-3-hexyne, etc.; and ketone peroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide, and the like; and azo compounds such as lauryl peroxide, azobisisobutyronitrile, and azobis(2,4-dimethylvaleronitrile), but are not limited thereto.

[0053] The organic peroxide may be an organic peroxide having a 1-hour half-life temperature of 120 to 135°C, for example, 120 to 130°C, 120 to 125°C, preferably 121°C. The "1-hour half-life temperature" refers to a temperature at which the half-life of the crosslinking agent becomes 1 hour. Depending on the 1-hour half-life temperature, the temperature at which the radical initiation reaction efficiently occurs varies, and therefore, when an organic peroxide having a 1-hour half-life temperature in the above-mentioned range is used as a crosslinking agent, the radical initiation reaction, i.e., the crosslinking reaction, can effectively proceed at the lamination process temperature for manufacturing an optoelectronic device.

[0054] The cross-linking agent may be included in an amount of 0.01 parts by weight or more and 5 parts by weight or less, based on 100 parts by weight of the polyolefin composition. Specific examples thereof include 0.01 parts by weight or more, 0.02 parts by weight or more, 0.04 parts by weight or more, 0.06 parts by weight or more, and 0.08 parts by weight or more, and may also be included in an amount of 5 parts by weight or less, 4 parts by weight or less, 3 parts by weight or less, and 2 parts by weight or less. When the cross-linking agent is included in an amount of less than 0.01 parts by weight, the effect of improving the degree of cross-linking is minimal, and when it is included in an amount of more than 5 parts by weight, the formability of final products such as encapsulating films and encapsulating sheets may be reduced, which may cause problems such as restrictions in the process, and may affect the physical properties of the encapsulating material.

[0055] In addition, the composition for the encapsulating film may include a crosslinking agent in addition to the crosslinking agent. By including the crosslinking agent in the composition for the encapsulating film, the degree of crosslinking between the film compositions by the crosslinking agent described above can be increased, thereby further improving the degree of crosslinking and stability in the final product.

[0056] The crosslinking agent may be any of various crosslinking agents known in the art, and for example, a compound containing at least one unsaturated group such as an allyl group or a (meth)acryloxy group may be used.

[0057] Examples of the compound containing the above-mentioned allyl group include polyallyl compounds such as triallyl isocyanurate (TAIC), triallyl cyanurate, diallyl phthalate, diallyl fumarate, or diallyl maleate, and examples of the compound containing the above-mentioned (meth)acryloxy group include poly(meth)acryloxy compounds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, or trimethylolpropane trimethacrylate, but are not particularly limited thereto.

[0058] The crosslinking agent may be included in an amount of 0.1 part by weight or more and 1 part by weight or less based on 100 parts by weight of the polyolefin composition. Specific examples thereof include 0.1 part by weight or more, 0.2 part by weight or more, 0.3 part by weight or more, and 0.4 part by weight or more, and further include 1 part by weight or less, 0.9 part by weight or less, 0.8 part by weight or less, 0.7 part by weight or less, and 0.6 part by weight or less. When the crosslinking agent is included in an amount of less than 0.1 part by weight, the effect of improving the crosslinking degree is minimal, and when it is included in an amount exceeding 1 part by weight, problems may arise that affect the physical properties of the final product, for example, the encapsulating film, and the production cost may increase.

[0059] Additionally, the composition for the encapsulating film may additionally include a silane coupling agent.

[0060] 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) can be used.

[0061] The above silane coupling agent may be included in an amount of 0.1 part by weight or more and 0.5 part by weight or less based on 100 parts by weight of the polyolefin composition. Specific examples thereof include 0.1 part by weight or more, 0.12 part by weight or more, 0.14 part by weight or more, 0.16 part by weight or more, and 0.18 part by weight or more, and further include 0.5 part by weight or less, 0.45 part by weight or less, 0.4 part by weight or less, 0.3 part by weight or less, and 0.35 part by weight or less. When the silane coupling agent is used in an amount of less than 0.1 part by weight, the adhesion to glass during the manufacture of a solar cell module is poor, allowing moisture to easily penetrate, thereby making it impossible to guarantee the long-term performance of the module. In addition, when used in an amount exceeding 0.5 part by weight, it is undesirable because it acts as a factor in increasing the YI (yellow index).

[0062] The above-mentioned photostabilizer can prevent photooxidation by capturing the active species that initiates photodegradation of the resin, depending on the intended use of the composition. The type of photostabilizer 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.

[0063] 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.

[0064] 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.

[0065] The content of the above-mentioned light stabilizer, UV absorber, and / or heat stabilizer is not particularly limited. That is, the content of the above-mentioned additives may be appropriately selected in consideration of the intended use of the resin composition, the shape or density of the additives, etc., and may typically be appropriately adjusted within the range of 0.01 to 5 parts by weight relative to 100 parts by weight of the total solid content of the composition for the sealant film.

[0066]

[0067] In addition, the present invention provides a sealing film formed from the composition for the sealing film described above.

[0068] The encapsulating film of the present invention can be manufactured by molding the aforementioned encapsulating film composition into a film or sheet shape. The molding method is not particularly limited, and for example, the encapsulating film can be manufactured by forming it into 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 manufacturing process are interconnected.

[0069] The thickness of the above-mentioned encapsulating film can be adjusted to about 10 to 2,000 μm, or about 100 to 1,250 μm, 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.

[0070]

[0071] 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. Various types and shapes of solar cell modules manufactured in the art including the encapsulant film can all be applied to the present invention.

[0072] 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.

[0073] The above backsheet is a weather-resistant film that protects the back surface of the solar cell module from the outside, and includes, for example, a fluorine resin sheet, a metal plate or metal foil such as aluminum, a cyclic olefin resin sheet, a polycarbonate resin sheet, a poly(meth)acrylic resin sheet, a polyamide resin sheet, a polyester resin sheet, and a composite sheet in which a weather-resistant film and a barrier film are laminated.

[0074] 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.

[0075] The solar cell module of the present invention is manufactured using a sealing film with minimized creep phenomenon, and thus hardly undergoes deformation even when used for a long period of time or in an extreme environment (e.g., maintains durability even under conditions of a temperature of 85°C and a humidity of 85%), and has excellent durability by minimizing delamination phenomenon, and can significantly suppress problems such as output reduction.

[0076]

[0077] Example

[0078] 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.

[0079]

[0080] [Manufacture of modified polyolefin]

[0081] Manufacturing Example 1

[0082] Ethylene / 1-butene copolymer (EBR; density 0.877 g / cm 3, melt index (190℃, 2.16kg load) 14 g / 10 min), 0.1012 mol of tris(vinyldimethylsiloxy)methylsilane as a reagent (silane compound) and 0.0021 mol of peroxide (Luperox 101) were mixed in 1 kg, and the mixture was injected at a constant speed through a syringe pump to carry out reactive extrusion, thereby manufacturing a modified polyolefin. At this time, the temperature of the twin-screw extruder used for reactive extrusion was set to 100-220℃, the screw feeder speed to 9.82 rpm, and the extruder screw speed to 200 rpm.

[0083]

[0084] Manufacturing Examples 2 to 8

[0085] A modified polyolefin was manufactured using the same method as Manufacturing Example 1, except that the copolymer type, reagent type and content, and peroxide content were changed as shown in Table 1 below.

[0086] Manufacturing Example 6 is a copolymer with a density of 0.876 g / cm 3 , ethylene / 1-octene copolymer (EOR) with a melting index (190℃, 2.16kg load) of 13 g / 10min was used.

[0087]

[0088] CopolymerReagent typeReagent contentPeroxide contentPreparation example 1EBRTris(vinyldimethylsiloxy)methylsilane0.1012 mol0.0021 molPreparation example 2EBR0.3373 mol0.007 molPreparation example 3EBRTris(vinyldimethylsiloxy)phenylsilane0.1012 mol0.0021 molPreparation example 4EBR1,3,5-Trivinyl-1,1,3,5,5-pentamethyltrisiloxane0.1012 mol0.0021 molPreparation example 5EBR2,4,6-Trimethyl-2,4,6-trivinylcyclotrisiloxane0.1012 mol0.0021 molPreparation example 6EOR0.1012 mol0.0021 molPreparation example 7EBR Tetravinylsilane 0.1012 mol 0.0021 mol Preparation example 8EBR 1,3-divinyltetramethyldisiloxane 0.3373 mol 0.007 mol

[0089]

[0090] Comparative Manufacturing Example 1

[0091] Ethylene / 1-butene copolymer (EBR; density 0.877 g / cm 3 , melt index (190℃, 2.16kg load) 14 g / 10min) for 100 parts by weight, 5.000 parts by weight of vinyltrimethoxysilane (VTMS) as a reagent (silane compound) and 0.2 parts by weight of peroxide (Luperox 101) were mixed, and the mixture was injected at a constant speed through a syringe pump to carry out reactive extrusion, thereby manufacturing a modified polyolefin. At this time, the temperature of the twin-screw extruder used for reactive extrusion was set to 100-220℃, the screw feeder speed to 9.82 rpm, and the extruder screw speed to 200 rpm.

[0092]

[0093] [Manufacture of polyolefin composition and encapsulating film]

[0094] Examples 1 to 8

[0095] The modified polyolefins of Manufacturing Examples 1 to 8 were used as polyolefin compositions, and a sealing film was manufactured using the following method.

[0096] The bowl temperature of the Haake Modular Torque Viscometer was set to 40°C. After the polyolefin composition was added to the bowl, 1.0 parts by weight of a crosslinking agent (TBEC), 0.5 parts by weight of a crosslinking aid (TAIC), and 0.2 parts by weight of a silane coupling agent (MEMO) were added based on 100 parts by weight of the polyolefin composition using an electric pipette. While stirring at 40 rpm at 40°C, the change in torque value over time was observed, and the impregnation was terminated when the torque value increased rapidly. Thereafter, the impregnated sample was press-molded to an average thickness of 0.5 mm at a low temperature (compressor barrel temperature of 90 to 100°C) that did not cause high-temperature crosslinking, thereby manufacturing a sheet-shaped encapsulating film.

[0097]

[0098] Examples 9 to 14

[0099] Modified polyolefin of Manufacturing Examples 3 and 5 and ethylene / 1-butene copolymer (EBR; density 0.877 g / cm 3 , melting index (190℃, 2.16kg load) 14 g / 10min) was mixed as shown in Table 2 below and used as a polyolefin composition.

[0100] A sealing film was manufactured in the same manner as in Examples 1 to 8, except that a polyolefin composition was used as a mixture as shown in Table 2 below.

[0101]

[0102] Modified polyolefin (wt%) EBR (wt%) Example 9 Manufacturing example 3 (5 wt%) 95 wt% Example 10 Manufacturing example 3 (30 wt%) 70 wt% Example 11 Manufacturing example 3 (50 wt%) 50 wt% Example 12 Manufacturing example 5 (5 wt%) 95 wt% Example 13 Manufacturing example 5 (30 wt%) 70 wt% Example 14 Manufacturing example 5 (50 wt%) 50 wt%

[0103]

[0104] Comparative Example 1

[0105] Ethylene / 1-butene copolymer (EBR; density 0.877 g / cm 3 , melting index (190℃, 2.16kg load) 14 g / 10min) was used as a polyolefin composition.

[0106] A sealing film was manufactured in the same manner as in Examples 1 to 8 except that the polyolefin composition was changed.

[0107]

[0108] Comparative Example 2

[0109] The modified polyolefin of Comparative Manufacturing Example 1 was used as a polyolefin composition.

[0110] A sealing film was manufactured in the same manner as in Examples 1 to 8 except that the polyolefin composition was changed.

[0111]

[0112] Experimental Example 1

[0113] The properties of the polyolefin compositions of Examples 1 to 14 and Comparative Examples 1 and 2 were evaluated according to the following method and are shown in Table 3.

[0114]

[0115] 1) Density

[0116] Measured using ASTM D-792.

[0117] 2) Melt Index (MI)

[0118] Measured according to ASTM D-1238 (condition E, 190℃, 2.16 kg load).

[0119] 3) Melt flow ratio (MFR)

[0120] The ratio of the melt index measured by ASTM D-1238 (Condition E, 190℃, 10 kg load) to the melt index measured by ASTM D-1238 (Condition E, 190℃, 2.16 kg load) (MI) 10 / MI2.16 ) was calculated.

[0121]

[0122] Density (g / cc)MI (dg / min)MFR (dg / min)Example 10.88007.28.9Example 20.88282.413.0Example 30.878610.67.7Example 40.88029.17.9Example 50.87923.99.8Example 60.87654.310.1Example 70.87909.28.1Example 80.87784.310.9Example 90.877113.76.8Example 100.877613.07.0Example 110.877712.47.4Example 120.877313.37.0Example 130.877711.07.7 Example 140.87809.18.5 Comparative Example 10.877014.06.8 Comparative Example 20.88289.68.2

[0123]

[0124] Experimental Example 2

[0125] NMR was measured for the polyolefin compositions of Examples 1 to 14 and Comparative Examples 1 and 2 according to the following method, and the analysis results are shown in Table 4.

[0126] The polyolefin composition was pretreated by immersing it in acetone at 60°C for 12 hours, removing the acetone, and washing it four times with clean acetone. The pretreated polyolefin composition was dissolved in a TCE-d2 solvent. 1 H NMR (373K) analysis was performed.

[0127] From the above NMR analysis results, the peak of the terminal double bond detected at 5.7 to 6.3 ppm includes some peaks of the terminal double bonds that the polyolefin before modification contained (i.e., the terminal double bonds originating from the unmodified portion). Through the hydrogen peaks originating from two terminal double bonds detected in a range that does not overlap with the range of 5.7 to 6.3 ppm among the terminal double bonds originating from the unmodified portion, the hydrogen peak of one terminal double bond detected at 5.7 to 6.3 ppm can be calculated. Therefore, by performing NMR analysis on the modified polyolefin and subtracting the hydrogen peak of one terminal double bond originating from the unmodified portion from the content of the terminal double bonds detected at 5.7 to 6.3 ppm, the content of the terminal double bonds originating from the modified portion in the modified polyolefin, which are detected at 5.7 to 6.3 ppm, can be obtained.

[0128] From the above NMR analysis results, the peak of methyl groups detected at 0.0 to 0.4 ppm is a characteristic peak of modified polyolefin, and the number of methyl groups was obtained by quantifying the peak of that portion.

[0129]

[0130] Peaks originating from modified portions in modified polyolefin Number of terminal double bonds detected at 5.7 to 6.3 ppm (number / total 1000C) Number of methyl groups detected at 0.0 to 0.4 ppm (number / total 1000C) Example 10.3073.613 Example 20.82610.787 Example 30.0951.463 Example 40.2463.549 Example 50.4340.983 Example 60.3471.127 Example 70.1760 Example 80.2550.985 Example 90.0050.073 Example 100.0290.439 Example 110.0480.732 Example 120.0220.049 Example 130.1300.295 Example 140.2170.492 Comparative Example 1--Comparative Example 200

[0131]

[0132] As can be seen from Table 4, although the degree of grafting during the reactive extrusion process differs for each reagent and depending on the amount of reagent, it was confirmed that a certain range of terminal double bonds (detected at 5.7 to 6.3 ppm) was detected in the polyolefin compositions of Examples 1 to 8 of the present invention using silane compounds containing two or more vinyl groups as reagents. In addition, it was confirmed that the polyolefin compositions of Examples 9 to 14 of the present invention, which partially contain modified polyolefins manufactured using such silane compounds, also detect terminal double bonds (detected at 5.7 to 6.3 ppm), although at a slightly lower level than Examples 1 to 8.

[0133] In the case of Comparative Example 2, although a modified polyolefin was manufactured by grafting a silane compound, the silane compound itself contained a vinyl group. Therefore, when manufacturing the modified polyolefin, the double bond of the vinyl group was broken and bonded to the polyolefin main chain. Therefore, it was confirmed that, among the peaks originating from the modified portion in the modified polyolefin during NMR measurement, a terminal double bond was not measured at 5.7 to 6.3 ppm.

[0134]

[0135] Experimental Example 3

[0136] After crosslinking sheets were manufactured using the sealing films of Examples 1 to 14 and Comparative Examples 1 and 2 by the method below, the crosslinking properties of the crosslinked sheets were measured by the method below, and the analysis results are shown in Table 5.

[0137] A 0.5 mm thick encapsulating film (10 cm X 10 cm) was placed between two release films (thickness: approximately 100 um), and crosslinked by lamination in a vacuum laminator at a process temperature of 145°C for a process time of 20 minutes (5 minutes of vacuum / 1 minute of pressurization / 14 minutes of continuous pressure).

[0138]

[0139] 1) Bridge

[0140] Cut the above cross-linked sheet into 3X3 mm using scissors 2 Cut to the size of 7X14 cm 2 The sides and bottom of a 120 mesh wire mesh were sealed with staples. The sheet was placed in the wire mesh, and the weight of the sheet was measured. The amount of sheet was 0.49 to 0.51 g. After placing the sheet, the top of the wire mesh was sealed with staples, and the total weight of the sample was measured. A solution of 10 g of BHT (dibutylhydroxytoluene) dissolved in 1,000 g of xylene was poured into a 2 L cylinder reactor, and 3 to 4 of the above samples were placed. The reactor was heated, and reflux was terminated after 5 hours from the time it started to boil. The samples in the reactor were taken out using a metal scoop and vacuum-dried at 140°C for 24 hours. The weight of the dried sample was measured, and the degree of crosslinking was calculated using the following mathematical formula 1. The degree of crosslinking can be determined as the average value of 3 to 4 samples refluxed in xylene.

[0141] [Mathematical Formula 1]

[0142] Cross-linking degree (%) = [(Weight of sheet after reflux) / (Weight of sheet before reflux)] x 100

[0143]

[0144] 2) Light transmittance (%)

[0145] The optical transmittance (380 to 1,000 nm) of the above-mentioned cross-linked sheet in the visible light range was measured using a Shimadzu UV-3600 spectrophotometer (measurement mode: transmittance, wavelength interval: 1 nm, measurement speed: medium).

[0146]

[0147] 3) Volume resistivity (Ωㆍcm)

[0148] Tests were conducted at room temperature based on ASTM D257. The cross-linked sheet was placed in a Keithley 8009 resistivity test fixture, and a 6517B Electrometer / High Resistance meter connected thereto applied a voltage of 1,000 V, and the volume resistivity was measured.

[0149]

[0150] Crosslinking degree (%) Light transmittance (%) Volume resistivity (Ωㆍcm) 550 nm Vis Example 181.99 3.09 2.5 4.2E+16 Example 283.89 2.09 2.12.1E+16 Example 381.19 2.29 2.35.7E+16 Example 480.29 2.19 2.44.9E+16 Example 585.29 2.59 2.71.1E+17 Example 690.59 2.09 2.21.3E+17 Example 778.49 2.39 2.54.7E+16 Example 875.09 2.79 2.53.5E+16 Example 974.792.592.45.5E+16 Example 1078.692.292.15.7E+16 Example 1180.092.392.55.4E+16 Example 1275.092.292.36.8E+16 Example 1380.492.392.17.1E+16 Example 1483.092.492.57.3E+16 Comparative Example 173.192.092.26.1E+16 Comparative Example 273.892.392.53.0E+16

[0151]

[0152] As can be seen in Table 5, in the case of Examples 1 to 14 containing a terminal double bond, i.e., a vinyl silane group, in the polyolefin composition, the light transmittance and volume resistivity were similar or equivalent to those of the comparative examples, but it was confirmed that the degree of crosslinking was significantly increased.

[0153] In the case of Comparative Example 2, a slightly improved crosslinking degree was confirmed compared to Comparative Example 1, which used a copolymer that was not modified using a reagent. However, the silane compound used in Comparative Example 2 is a reagent commonly used in the production of graft polyolefin, and since the compound itself contains one vinyl group, an increase in terminal double bonds due to the modified polyolefin in the polyolefin after grafting did not occur, and it was confirmed that a significantly lower crosslinking degree was shown compared to the examples of the present application.

Claims

1. A polyolefin composition comprising a modified polyolefin containing a vinyl silane group.

2. In claim 1, The above modified polyolefin was immersed in acetone at 60°C for 12 hours, washed, and then dissolved in TCE-d2 solvent. 1 A polyolefin composition in which the content of terminal double bonds detected at 5.7 to 6.3 ppm among peaks originating from a modified portion in the modified polyolefin during H NMR (373K) analysis is 0.001 or more and 1 or less per 1000 total carbon atoms.

3. In claim 1, A polyolefin composition wherein the vinyl silane group is derived from a silane compound containing two or more vinyl groups.

4. In claim 3, A polyolefin composition wherein the above silane compound is selected from the group consisting of tris(vinyldimethylsiloxy)methylsilane, tris(vinyldimethylsiloxy)phenylsilane, 1,3,5-trivinyl-1,1,3,5,5-pentamethyltrisiloxane, 2,4,6-trimethyl-2,4,6-trivinylcyclotrisiloxane, tetravinylsilane, and 1,3-divinyltetramethyldisiloxane.

5. In claim 1, The above polyolefin is a polyolefin composition which is a copolymer of ethylene and an alpha-olefin comonomer.

6. In claim 5, A polyolefin composition wherein the above alpha-olefin comonomer is an alpha-olefin comonomer having 3 to 12 carbon atoms.

7. In claim 6, A polyolefin composition comprising at least one selected from the group consisting of 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-eicosene, norbornene, norbornadiene, ethylidenenorbornene, phenylnorbornene, vinylnorbornene, dicyclopentadiene, 1,4-butadiene, 1,5-pentadiene, 1,6-hexadiene, styrene, alpha-methylstyrene, divinylbenzene, and 3-chloromethylstyrene.

8. A composition for a sealing film comprising a polyolefin composition according to any one of claims 1 to 7.

9. A sealing film formed from the composition for a sealing film of claim 8.

10. A solar cell module comprising the encapsulating film of claim 9.