KR101770459B1 - Optical sheet - Google Patents
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- KR101770459B1 KR101770459B1 KR1020140191743A KR20140191743A KR101770459B1 KR 101770459 B1 KR101770459 B1 KR 101770459B1 KR 1020140191743 A KR1020140191743 A KR 1020140191743A KR 20140191743 A KR20140191743 A KR 20140191743A KR 101770459 B1 KR101770459 B1 KR 101770459B1
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract
The present invention relates to an optical sheet and a photovoltaic module including the optical sheet. The optical sheet according to the present application not only has excellent surface hardness and scratch resistance, but also has a high light transmittance and can exhibit a high light transmittance, And thus it is useful for photovoltaic modules.
Description
The present application relates to an optical sheet and a photovoltaic module including the same.
There is a growing interest in renewable energy and clean energy due to global environmental problems and depletion of fossil fuels. Among them, photovoltaic energy is attracting attention as a representative pollution-free energy source that can solve environmental pollution problem and fossil fuel depletion problem have.
Photovoltaic (PV) solar photovoltaic (PV) technology is a device that converts sunlight into electric energy. Since it is required to be exposed to the external environment for a long time in order to easily absorb sunlight, various packaging for protecting the cell is performed, ), And these units are referred to as photovoltaic modules.
In general, a photovoltaic module uses an optical sheet having excellent weather resistance and durability to stably protect a photovoltaic cell even when exposed to an external environment for a long period of time. In order to improve the weatherability, it is necessary to lower the ultraviolet transmittance into the photovoltaic module. For this purpose, it is common to use an ultraviolet absorber. In addition, in order to improve the durability, it is necessary to increase the surface hardness.
Patent Documents 1 to 3 propose a technique for satisfying the physical properties required for the back sheet among the optical sheets.
The present application provides an optical sheet and a photovoltaic module including the same.
The present application relates to an optical sheet.
The exemplary optical sheet may be an optical sheet for a photovoltaic module applicable to a photovoltaic module. More specifically, the optical sheet may be an optical sheet applicable as a front substrate or a back sheet included in the photovoltaic module, and more preferably, it may be an optical sheet applicable as a back sheet. In the present specification, the above-mentioned "optical sheet for a photovoltaic module" may be referred to as an "optical sheet".
In one example, the optical sheet of the present application comprises a base layer; And a surface layer formed on at least one surface of the substrate layer.
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram schematically showing a cross section of an optical sheet according to the present application. FIG. The
The substrate layer is not particularly limited, and various materials known in the art can be used, and can be appropriately selected depending on the required functions and applications.
As the base layer, a single sheet such as an acrylic film, a polyether film, a polyester film, a polyolefin film, a polyamide film, a polyurethane film, a polycarbonate film and a polyimide film, A laminated sheet of polymer films, or a pneumatic article, and a polyester film can be usually used, but the present invention is not limited thereto. Examples of the polyester film include at least one selected from the group consisting of a polyethylene terephthalate (PET) film, a polyethylene naphthalate (PEN) film, and a polycarbonate (PC) film , But is not limited thereto.
The thickness of the base layer is not particularly limited, but may be, for example, in the range of 25 탆 to 300 탆, 100 탆 to 280 탆, or 150 탆 to 250 탆. By adjusting the thickness of the base layer within the above-mentioned range, the mechanical properties and handleability of the optical sheet can be improved. However, the thickness of the base layer according to the embodiments of the present application is not limited to the above-mentioned range, and it can be suitably adjusted as required.
In order to improve the adhesion with the surface layer described above, the base layer is subjected to spark discharge treatment at a high frequency such as corona treatment or plasma treatment on one side or both sides thereof; Heat treatment; Flame treatment; Anchor treatment; Coupling agent treatment; Primer treatment or a gas phase Lewis acid (ex. BF 3), can be done by a surface treatment such as a chemical activation treatment with sulfuric acid or hot sodium hydroxide. The surface treatment method may be carried out by any well-known means generally used in this field.
In addition, from the viewpoint of improving the physical properties such as moisture barrier properties, the substrate layer may be formed with an inorganic oxide deposited layer on one side or both sides, if necessary. The kind of the inorganic oxide is not particularly limited, and any inorganic oxide may be employed as long as it has moisture barrier properties. For example, silicon oxide or aluminum oxide can be used. The method of forming the inorganic oxide vapor deposition layer on one side or both sides of the substrate layer is not particularly limited and may be a vapor deposition method generally used in this field. When the inorganic oxide deposit layer is formed on one surface or both surfaces of the substrate layer, the above-described surface treatment may be performed on the deposition layer after the inorganic oxide deposit layer is formed on the surface of the substrate layer.
The surface layer is not particularly limited, but may be, for example, an ultraviolet blocking surface layer. In this specification, the " ultraviolet-shielding surface layer " may be referred to as a " surface layer ".
In one example, the surface layer comprises a polyfunctional (meth) acrylate based ultraviolet curable monomer or oligomer; And ultraviolet absorber may be cured to form the composition. As used herein, the term " (meth) acrylate " may be understood to include acrylate and methacrylate.
The polyfunctional (meth) acrylate-based ultraviolet ray-curable monomer or oligomer is not particularly limited as long as it is contained in the composition and can be cured to have transparency for application to the optical sheet, Trimethylolpropane triacrylate, glycerin propoxylated triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol pentaacrylate, pentaerythritol pentaacrylate, pentaerythritol pentaacrylate, pentaerythritol triacrylate, Dipentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, urethane acrylate, ester acrylate, epoxy acrylate, and ether acrylate, and ethylene oxide (EO) thereof, ) Denaturation And a compound having a large number of functional groups per molecular weight such as pentaerythritol triacrylate or dipentaerythritol tetraacrylate is preferable from the viewpoint of improving the surface hardness of the optical sheet Do.
Since the optical sheet of the present application contains the above-mentioned polyfunctional (meth) acrylate-based ultraviolet ray-curable monomer or oligomer, properties such as transparency of the optical sheet can be ensured and the surface hardness of the surface layer of the optical sheet And the physical properties such as scratch resistance can be secured.
In one example, the ultraviolet absorber may be a compound represented by the following formula (1).
[Chemical Formula 1]
In Formula 1,
R 1 is hydrogen, halogen, an alkoxy group having 1 to 6 carbon atoms, or an aryl group;
R 2 is hydrogen, an alkyl group having 1 to 6 carbon atoms, or an aryl group;
R 3 represents R 4 -R 5 -R 6 ,
R 4 represents a single bond or oxygen,
R 5 represents a single bond or represents - (CH 2 ) m O-, -CH (CH 3 ) CH 2 O-, -CH 2 CH (CH 3 ) O-, - (CH 2 ) m OCH 2 - CH (CH 3) CH 2 OCH 2 - and -CH 2 CH (CH 3) OCH 2 - represents one selected from the group consisting of,
R 6 represents an acryloyl group, a methacryloyl group, a styrene group or a vinyl group,
n and m each independently represent an integer of 1 to 4;
In the above formula (1), preferably
R < 1 > is hydrogen;
R 2 is hydrogen or an alkyl group having 1 to 6 carbon atoms;
R 3 represents R 4 -R 5 -R 6 ,
R 4 represents a single bond,
R 5 represents - (CH 2 ) m O-,
R 6 represents an acryloyl group or a methacryloyl group,
and m represents an integer of 1 to 3.
The ultraviolet absorber is not particularly limited as long as it has ultraviolet ray absorbing ability, but examples thereof include 2- (2'-hydroxy-5'-methacryloxyethylphenyl) -2H-benzotriazole or 2- 2,3-epoxy-propoxy) -benzophenone.
In one example, the ultraviolet absorber is used in an amount of 1 part by weight to 20 parts by weight, 2 parts by weight to 15 parts by weight or 5 parts by weight to 12 parts by weight relative to 100 parts by weight of the polyfunctional (meth) acrylate based ultraviolet curable monomer or oligomer ≪ / RTI > In the present specification, the unit " part by weight " may mean the ratio of the weight between the respective components. It is possible to provide an optical sheet capable of improving weatherability when applied to a photovoltaic module through ultraviolet shielding ability while maintaining a high light transmittance by appropriately adjusting the content of the ultraviolet absorbent within the above-mentioned range.
The surface layer included in the optical sheet of the present application may be any of the above-mentioned polyfunctional (meth) acrylate-based ultraviolet-curable monomers or oligomers; And an ultraviolet absorber, wherein the ultraviolet absorber may have a reactor capable of copolymerizing with the monomer and / or the oligomer.
The ultraviolet absorber contained in the surface layer of the optical sheet of the present application has a reactor capable of copolymerizing with the polyfunctional (meth) acrylate-based ultraviolet-curing monomer and / or oligomer, whereby the polyfunctional (meth) / Or oligomers; And ultraviolet absorber so as to have a higher light transmittance and a low haze value to ensure physical properties such as transparency and at the same time to enhance the ultraviolet shielding ability and to improve the properties such as weather resistance when applied to a photovoltaic module It is possible to provide an optical sheet which can be improved.
The surface layer included in the optical sheet of the present application may be any of the aforementioned polyfunctional (meth) acrylate-based ultraviolet monomers or oligomers; And ultraviolet absorber may be cured.
In one example, the composition may further comprise a (meth) acrylic acid ester-based monomer and / or a crosslinkable monomer containing at least one crosslinkable functional group within the scope of securing the desired physical properties of the optical sheet of the present application .
The kind of the (meth) acrylate monomer is not particularly limited. In the present application, for example, alkyl (meth) acrylate can be used, and specifically, an alkyl (meth) acrylate having an alkyl group having 1 to 14 carbon atoms, preferably 1 to 8 carbon atoms in terms of controlling the adhesive force of the surface layer ) Acrylate may be used. Examples of such monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, (Meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-ethylbutyl (meth) acrylate, n-octyl , Isooctyl (meth) acrylate or isononyl (meth) acrylate. Of these, one kind or a mixture of two or more kinds can be used.
The crosslinkable monomer means a compound which simultaneously contains both a copolymerizable functional group such as a carbon-carbon double bond in the molecule and a crosslinkable functional group. The crosslinkable monomer may serve to provide a crosslinking point through a crosslinkable functional group or to control the adhesive force under high temperature or high humidity conditions.
The cross-linkable monomer is not particularly limited, and a monomer that can be used usually can be used. Examples of the crosslinkable monomer include a hydroxy group-containing monomer and a carboxyl group-containing monomer, which may be used alone or in combination. Examples of the hydroxy group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (Meth) acrylate, 2-hydroxyethyleneglycol (meth) acrylate or 2-hydroxypropyleneglycol (meth) acrylate; Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, 2- (meth) acryloyloxyacetic acid, 3- (meth) acryloyloxypropyl acid, 4- (meth) acryloyloxybutyric acid, Butyric acid, itaconic acid, maleic acid, and the like.
In the present application, the composition may contain the (meth) acrylate monomer and the crosslinkable monomer in an appropriate ratio, thereby securing the adhesion between the base layer and the surface layer.
In addition, the composition may further include a copolymerizable monomer in addition to the (meth) acrylic acid ester monomer and the crosslinkable monomer within the range of securing the desired physical properties of the optical sheet of the present application.
The copolymerizable monomer is not particularly limited as long as it is a copolymerizable monomer, and examples thereof include monomers such as N-vinylformamide and the like having 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, N-alkenylformamide which may have 8 or an alkenyl group having 2 to 4 carbon atoms; Acrylamide, N, N-diphenyl (meth) acrylamide, N- (n-dodecyl) (meth) acrylamide, N- (meth) acrylamide such as N, N-dimethyl acrylamide or N-hydroxyethyl acrylamide, N-alkyl (meth) acrylamide (Meth) acrylamide, N, N-dialkyl (meth) acrylamide or N, N-diaryl (meth) acrylamide; Alkoxyalkyl (meth) acrylates such as 2-methoxyethyl (meth) acrylate and the like; Dihydrodicyclopentadienyl acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, cyclopropyl (meth) acrylate, acrylate, N-naphthyl acrylate, 2-phenoxyethyl (meth) acrylate, phenyl (meth) acrylate, Acrylate, 2-phenylethyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate or (Meth) acrylate having a saturated or unsaturated cyclic hydrocarbon group or an aromatic group such as cyclohexyl (meth) acrylate and the like; Or styrene may be exemplified.
The method of polymerizing the composition is not particularly limited, and may be carried out by mixing the above-mentioned monomers in an appropriate ratio and subjecting them to solution polymerization, photo polymerization, bulk polymerization, suspension polymerization, Or by emulsion polymerization. [0033] The term " polymer " If necessary in this process, suitable polymerization initiators or molecular weight regulators, chain transfer agents and the like may be used together.
The surface layer may further comprise a curing agent capable of curing the polymer of the composition. As the curing agent, at least two or more, two to ten, two to eight, two to six, or two to four functional groups capable of reacting with the crosslinkable functional group contained in the polymer of the composition A hardener may be used. As such a curing agent, an appropriate type may be selected and used from among conventional curing agents such as an isocyanate curing agent, an epoxy curing agent, an aziridine curing agent or a metal chelating curing agent in consideration of the kinds of crosslinkable functional groups of the polymer of the composition.
Examples of the isocyanate curing agent include diisocyanate compounds such as tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isoboron diisocyanate, tetramethylxylene diisocyanate, and naphthalene diisocyanate; and diisocyanate compounds such as diisocyanate compound And a reaction product of a polyol such as trimethylolpropane or an isocyanurate adduct of the above diisocyanate compound. Of these, xylene diisocyanate or hexamethylene diisocyanate can be preferably used. As the epoxy curing agent Is preferably at least one selected from the group consisting of ethylene glycol diglycidyl ether, triglycidyl ether, trimethylolpropane triglycidyl ether, N, N, N ', N'- tetraglycidylethylenediamine and glycerin diglycidyl ether There is at least one member selected from the group true can be exemplified.
Examples of the aziridine curing agent include N, N'-toluene-2,4-bis (1-aziridine carboxamide), N, N'-diphenylmethane-4,4'- (2-methyl aziridine) or tri-1-aziridinyl phosphine oxide, and the like, but not limited thereto, and the metal chelate Examples of the curing agent include compounds in which a polyvalent metal such as aluminum, iron, zinc, tin, titanium, antimony, magnesium and / or vanadium is coordinated to acetylacetone or ethyl acetoacetate, and the like.
The curing agent is contained in a proportion of, for example, 0.01 to 5 parts by weight, 0.015 to 4 parts by weight, 0.02 to 3 parts by weight or 0.025 to 1 part by weight relative to 100 parts by weight of the polymer of the composition . The hardening agent can be adjusted to be included in the surface layer in the above-mentioned range, so that the physical properties such as the adhesive strength of the surface layer can be secured.
The surface layer may further include at least one additive selected from the group consisting of a coupling agent, a tackifier, an antioxidant, a colorant, a reinforcing agent, a filler, a defoamer, a surfactant and a plasticizer, if necessary, .
The composition contained in the optical sheet of the present application may further contain a fluororesin in addition to the above-mentioned components from the viewpoint of enhancing weatherability.
As the fluororesin, various resins containing fluorine atoms known in the art can be used. Examples of the fluororesin include vinylidene fluoride (VF), vinyl fluoride (VF), tetrafluoroethylene (TFE), hexafluoropropylene (HFP), and the like. Perfluoroethyl vinyl ether (PMVE, perfluoro (methylvinylether)), perfluoroethyl vinyl ether (PMVE), perfluoroethyl vinyl ether Perfluoro (ethyl vinyl ether), perfluoropropyl vinyl ether (PPVE), perfluorohexyl vinyl ether (PHVE), perfluoro-2,2-dimethyl-1,3-dioxole (PDD) Copolymers or mixtures thereof comprising at least one monomer selected from the group consisting of methylene-4-methyl-4-methyl-1,3-dioxolane (PMD) in polymerized form, Quot; The fluororesin is a homopolymer or copolymer comprising vinylidene fluoride (VDF) in polymerized form; Or a mixture comprising the same.
The type of the comonomer that can be contained in the form of the polymer in the copolymer is not particularly limited and includes, for example, tetrafluoroethylene (TFE), hexafluoropropylene (HFP), chlorotrifluoro But are not limited to, ethylene (CTFE), trifluoroethylene, hexafluoroisobutylene, perfluorobutyl ethylene, perfluoro (methylvinylether), and perfluoroethyl vinyl ether perfluorohexyl vinyl ether (PHVE), perfluoro-2,2-dimethyl-1,3-dioxole (PDD), and perfluoro-2 Methylene-4-methyl-1,3-dioxolane (PMD), and the like, and examples thereof include at least one of hexafluoropropylene and chlorotrifluoroethylene. However, But is not limited thereto.
In one example, the fluororesin may be a mixture of a homopolymer comprising vinylidene fluoride in polymerized form and a copolymer of vinylidene fluoride and hexafluoropropylene, or a mixture of vinylidene fluoride and chlorotrifluoro , A copolymer of ethylene and a copolymer of vinylidene fluoride and hexafluoropropylene.
The content of the comonomer contained in the copolymer is not particularly limited and may be, for example, about 0.5 to 50 wt%, 1 to 40 wt%, and 7 wt% based on the total weight of the copolymer % To 40 wt%, 10 wt% to 30 wt%, or 10 wt% to 20 wt%. By controlling the content of the comonomer in the above-described range, it is possible to further improve the adhesive force while ensuring the durability and weather resistance of the optical sheet.
The weight average molecular weight of the fluororesin may be from 50,000 to 100, and may be from 100,000 to 700,000, or from 300,000 to 50,000, but is not limited thereto. As used herein, the term " weight average molecular weight " is a conversion value of standard polystyrene measured by GPC (Gel Permeation Chromatograph). In embodiments of the present application, excellent workability and other physical properties can be secured by controlling the weight average molecular weight of the fluororesin within the above range.
The composition may further comprise a photoinitiator.
Examples of the photoinitiator include a photoinitiator such as a benzoin-based initiator, a hydroxyketone-based initiator, an amino ketone-based initiator, or a phosphine oxide-based initiator, which is capable of generating radicals by light irradiation, Initiators may be used without limitation.
More specifically, examples of the photoinitiator include? -Hydroxyketone compounds (e.g., IRGACURE 184, IRGACURE 500, IRGACURE 2959, DAROCUR 1173, Ciba Specialty Chemicals); Phenylglyoxylate-based compounds (ex IRGACURE 754, DAROCUR MBF; Ciba Specialty Chemicals); Benzyldimethylketal compounds (ex IRGACURE 651; Ciba Specialty Chemicals); α-aminoketone-based compounds (ex IRGACURE 369, IRGACURE 907, IRGACURE 1300, Ciba Specialty Chemicals); Monoacylphosphine based compounds (MAPO) (ex. DAROCUR TPO; Ciba Specialty Chemicals); Bisacylphosphine compounds (BAPO) (ex IRGACURE 819, IRGACURE 819DW; Ciba Specialty Chemicals); Phosphine oxide-based compounds (ex IRGACURE 2100; Ciba Specialty Chemicals); Metallocene compounds (ex IRGACURE 784; Ciba Specialty Chemicals); Iodonium salt (ex.IRGACURE 250 from Ciba Specialty Chemicals); And mixtures of at least one of the foregoing, and the like, but are not limited thereto.
The photoinitiator may be included in an amount of 1 part by weight to 10 parts by weight, 3 parts by weight to 8 parts by weight or 4 parts by weight to 6 parts by weight based on 100 parts by weight of the polyfunctional (meth) acrylate based ultraviolet curable monomer or oligomer. When the content of the photoinitiator is too small, the effect due to the addition may be insignificant. When the content is too large, the physical properties such as durability and transparency may be adversely affected.
The composition may further include a pigment and / or a filler for improving the power generation efficiency of the solar cell and improving the physical properties of the optical sheet for a photovoltaic module. Examples of the pigment and / or filler include titanium dioxide, silica, Alumina, calcium carbonate, barium sulfate, carbon black, and metal oxide, and pigments for imparting black pigments and other colors such as carbon black can also be used.
The thickness of the surface layer may be in the range of 1 탆 to 30 탆, 2 탆 to 20 탆, or 3 탆 to 10 탆. By adjusting the thickness of the surface layer within the above-mentioned range, light transmittance and ultraviolet shielding ability can be enhanced and manufacturing cost can be reduced.
In addition, the optical sheet of the present application can increase the hardness of the surface layer by including the above-mentioned components in the surface layer, and can secure the scratch resistance to an excellent level. In one example, the surface hardness of the surface layer may be not less than HB on the pencil hardness, not less than 1H, or not less than 2H. The higher the surface hardness of the surface layer, the better the scratch resistance. Therefore, the upper limit is not particularly limited, but may be, for example, about 8H, 6H or 5H.
The optical sheet of the present application may further include various functional layers known in the industry as needed in addition to the above-described layers.
Examples of the functional layer include an adhesive layer or an insulating layer. The adhesive layer and the insulating layer may be sequentially formed on the other surface of the substrate layer when the reflective layer is formed on one surface of the substrate layer.
The adhesive layer or insulating layer may be formed in various ways known in the art. The insulating layer may be, for example, a layer composed of ethylene vinyl acetate (EVA) or low density linear polyethylene (LDPE). The layer composed of the ethylene vinyl acetate (EVA) or the low density linear polyethylene (LDPE) functions not only as an insulating layer but also an adhesive force of the encapsulant of the photovoltaic module to reduce the manufacturing cost, It is possible to simultaneously perform the function of maintaining excellent.
The optical sheet of the present application has an average transmittance of 75% or more for light having a wavelength of 400 nm to 420 nm, for example, in terms of securing physical properties of ultraviolet shielding ability; The average value of the transmittance for light having a wavelength of 300 nm to 320 nm may be 5% or less.
In another example, the optical sheet of the present application can satisfy the following general formula (1).
[Formula 1]
| P-Q | ≤ 5 nm
In the formula (1), P represents the shortest wavelength at which the transmittance to light in the wavelength region of 320 nm or more measured before the PCT (Pressure Cooker Test) test is 10%, and Q represents the wavelength Is the shortest wavelength value at which the transmittance to the light is 10%
The PCT test refers to a test in which the optical sheet is exposed for 50 hours at 121 ° C and 100% relative humidity.
The optical sheet of the present application has excellent ultraviolet shielding ability, and X of the above general formula can exhibit a value within a range of 360 nm to 380 nm. Further, the optical sheet of the present application is adjusted to satisfy the above-mentioned general formula (1) so that the ultraviolet ray blocking rate is excellent in the surface layer and the ultraviolet ray blocking rate does not change with the lapse of time, so that deterioration of the base layer can be prevented, It is possible to secure an excellent level of long-term weatherability.
The method for producing the optical sheet of the present application is not particularly limited, and examples thereof include the above-mentioned multifunctional (meth) acrylate-based ultraviolet-curing monomer or oligomer; And a surface layer formed by curing a composition containing an ultraviolet absorber may be coated on one side or both sides of the above-mentioned base layer.
The coating method may be carried out by a conventional coating method, for example, the above-mentioned polyfunctional (meth) acrylate-based UV-curable monomer or oligomer; And a UV absorber may be applied to a suitable process substrate by a conventional means such as a bar coater and then cured.
The method of curing the coating liquid is not particularly limited and may be, for example, curing through appropriate heating, drying and / or aging. Preferably, curing by irradiation with electromagnetic waves such as ultraviolet (UV) Method can be employed.
The present application also relates to photovoltaic modules.
In one example, the photovoltaic module comprises a front substrate; A back sheet, and two or more photovoltaic cells disposed between the front substrate and the back sheet and spaced apart from each other.
In the photovoltaic module of the present application, the front substrate or the back sheet may be the optical sheet described above.
The specific types of the front substrate and the photovoltaic cell that can be used in the above are not particularly limited. For example, the front substrate may be a conventional plate glass; Or a transparent composite sheet obtained by laminating a glass, a fluororesin sheet, a weather-resistant film and a barrier film. The photovoltaic cell may be, for example, an active layer of the silicon wafer type or a thin film active layer formed by chemical vapor deposition . In addition, the photovoltaic cell may be an n-type cell or a p-type cell, and may be an n-type cell, but is not limited thereto.
The optical sheet according to the present application is excellent in surface hardness and scratch resistance, has high light transmittance and can exhibit high light transmittance, is excellent in long-term weather resistance due to no change with time against ultraviolet shielding ability, and is useful for photovoltaic modules.
BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram exemplarily showing a cross section of an optical sheet according to the present application. Fig.
2 is a graph showing the ultraviolet transmittance of the optical sheets prepared in Examples and Comparative Examples of the present application.
Hereinafter, the present application will be described in more detail by way of examples according to the present application and comparative examples not complying with the present application, but the scope of the present application is not limited by the following examples.
Hereinafter, physical properties in Examples and Comparative Examples were evaluated in the following manner.
One. Hayes ( haze ) And yellowness Yellow Index , YI ) Measure
The haze alc yellowness (YI) of the optical sheet (thickness: 110 mu m) prepared in Examples and Comparative Examples was measured according to JIS K 7105-1 standard using a haze meter (COH-400, Nippon Denshoku) , Are shown in Table 1.
2. Change in ultraviolet transmittance over time
Using the metal halide ultraviolet lamp, the optical sheets prepared in Examples and Comparative Examples were formed into specimens of 7 cm in width and 7 cm in width at the bottom of the ultraviolet lamp, the specimens were fixed, the ultraviolet intensity meter was placed at the bottom of the specimen , Ultraviolet ray intensity was measured, and ultraviolet ray transmittance was measured using the change in ultraviolet ray intensity by the optical sheet, and it was measured immediately after the optical sheet was manufactured (shown in Examples and Comparative Examples) and 121 ° C and 100% (Shown in Example 1 after
≪ Preparation of composition >
Manufacturing example 1. Preparation of composition (A)
20 g of methyl ethyl ketone (MEK), 20 g of butyl acetate (BA), 20 g of propylene glycol monomethyl ether acetate (PGMEA) and 30 g of dipentaerythritol hexaacrylate (DPHA) were mixed homogeneously, and Irgacure 184 (Manufactured by Ciba Geigy) and Darocur-1173 (manufactured by Ciba Specialty Chemicals) were added and mixed. Thereafter, 1.5 g of reactive UVA additive RUVA-93 (manufactured by Otsuka Chemical Co., Ltd.) was added to and mixed with the mixed solvent to prepare a composition (A).
Manufacturing example 2. Preparation of composition (B)
20 g of methyl ethyl ketone (MEK), 20 g of butyl acetate (BA), 20 g of propylene glycol monomethyl ether acetate (PGMEA) and 30 g of dipentaerythritol hexaacrylate (DPHA) were mixed homogeneously, and Irgacure 184 (Manufactured by Ciba Geigy) and Darocur-1173 (manufactured by Ciba Specialty Chemicals) were added and mixed. Then, 1.5 g of UV531 (Cytec, Inc.) as an additive type UVA additive was added to and mixed with the mixed solvent to prepare a composition (B).
< Optical sheet And photovoltaic module &
Example
The obtained composition (A) was coated on both sides of a PET (poly (ethylene terephthalate)) film (thickness: 100 m) and dried to form a surface layer, and then an optical sheet was prepared.
Further, a plate glass (thickness: about 5 mm), a sealing material having a thickness of 450 탆, a crystal silicon wafer photovoltaic cell, a sealing material having a thickness of 160 탆 and a back sheet prepared above were laminated in this order. Min to produce a photovoltaic module.
Comparative Example
An optical sheet and a photovoltaic module were prepared in the same manner as in Example except that the composition (B) prepared in Preparation Example 2 was used in place of the composition (A) used in Examples.
The results of physical properties measured for the above Examples and Comparative Examples are shown in Table 1 below.
As shown in Table 1, the optical sheet (Examples) of the present application can exhibit haze and yellowness at a low level at the same time as the optical sheet (Comparative Example) including the additive type ultraviolet screening agent, Respectively. Further, as shown in FIG. 2, since the optical sheet (Example) of the present application has a lower change in UV blocking rate with time compared to the optical sheet (Comparative Example) comprising the additive type ultraviolet screening agent, It is confirmed that it can be excellent.
110: Optical sheet
111: substrate layer
112: Surface layer
Claims (14)
And an ultraviolet-shielding surface layer formed on at least one surface of the substrate layer,
An average value of transmittance for light in a wavelength range of 400 nm to 420 nm is 75% or more;
An average value of transmittance for light in a wavelength range of 300 nm to 320 nm is 5% or less;
An optical sheet for a photovoltaic module satisfying the following general formula:
[Formula 1]
| PQ | ≤ 5 nm
In the formula (1), P represents the shortest wavelength at which the transmittance to light in the wavelength region of 320 nm or more measured before the PCT (Pressure Cooker Test) test is 10%, and Q represents the wavelength Is the shortest wavelength value at which the transmittance to the light is 10%
The PCT test refers to a test in which the optical sheet is exposed for 50 hours at 121 ° C and 100% relative humidity.
Wherein the ultraviolet absorber has a reactor capable of copolymerizing with the monomer or oligomer.
[Chemical Formula 1]
In Formula 1,
R 1 is hydrogen, halogen, an alkoxy group having 1 to 6 carbon atoms, or an aryl group;
R 2 is hydrogen, an alkyl group having 1 to 6 carbon atoms, or an aryl group;
R 3 represents R 4 -R 5 -R 6 ,
R 4 represents a single bond or oxygen,
R 5 represents a single bond or represents - (CH 2 ) m O-, -CH (CH 3 ) CH 2 O-, -CH 2 CH (CH 3 ) O-, - (CH 2 ) m OCH 2 - CH (CH 3) CH 2 OCH 2 - and -CH 2 CH (CH 3) OCH 2 - represents one selected from the group consisting of,
R 6 represents an acryloyl group, a methacryloyl group, a styrene group or a vinyl group,
n and m each independently represent an integer of 1 to 4;
R < 1 > is hydrogen; R 2 is hydrogen or an alkyl group having 1 to 6 carbon atoms;
R 3 represents R 4 -R 5 -R 6 , R 4 represents a single bond, R 5 represents - (CH 2 ) m O-, R 6 represents an acryloyl group or a methacryloyl group,
and m represents an integer of 1 to 3.
Wherein the front substrate or the back sheet is an optical sheet for a photovoltaic module according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020140191743A KR101770459B1 (en) | 2014-12-29 | 2014-12-29 | Optical sheet |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020140191743A KR101770459B1 (en) | 2014-12-29 | 2014-12-29 | Optical sheet |
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| Publication Number | Publication Date |
|---|---|
| KR20160080188A KR20160080188A (en) | 2016-07-07 |
| KR101770459B1 true KR101770459B1 (en) | 2017-08-22 |
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| Application Number | Title | Priority Date | Filing Date |
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| KR1020140191743A KR101770459B1 (en) | 2014-12-29 | 2014-12-29 | Optical sheet |
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| KR (1) | KR101770459B1 (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007138117A (en) | 2005-11-22 | 2007-06-07 | Nippon Shokubai Co Ltd | Ultraviolet absorbing adhesive composition |
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| US8865312B2 (en) | 2010-06-25 | 2014-10-21 | Riken Technos Corp. | Coating composition for solar cell backsheet and solar cell backsheet |
| KR20130077048A (en) | 2011-12-29 | 2013-07-09 | 한국단자공업 주식회사 | Power distribution unit |
| JP5952838B2 (en) | 2012-01-17 | 2016-07-13 | デンカ株式会社 | Multilayer sheet, solar cell backsheet, and solar cell module |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007138117A (en) | 2005-11-22 | 2007-06-07 | Nippon Shokubai Co Ltd | Ultraviolet absorbing adhesive composition |
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| KR20160080188A (en) | 2016-07-07 |
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