KR101762455B1 - Resin composition for photovoltaic modules, Multi-layered film and Photovoltaic modules comprising the multi-layered film - Google Patents

Abstract

The present invention relates to a resin composition for a photovoltaic module, a multilayer film, a manufacturing method thereof, a backsheet for a photovoltaic module, and a photovoltaic module. INDUSTRIAL APPLICABILITY The resin composition for a photovoltaic module of the present invention contains a fluorine resin and a blocked crosslinking agent and improves the pot life of the varnish and thus has no restriction on the change of the process conditions, , Pin holes or voids are less likely to be generated when the resin composition of the present invention is coated on a substrate and then dried, and adhesion to a substrate can be maintained to be excellent. In addition, the resin composition for a photovoltaic module of the present invention can be coated on a substrate in a one-part system, and the manufacturing cost can be reduced since no additional equipment is required in the two-part system.

Description

[0001] The present invention relates to a resin composition for a photovoltaic module, a multilayer film, and a photovoltaic module including the same. [0002] Resin composition for photovoltaic modules, a multi-layered film and a photovoltaic module,

The present invention relates to a resin composition for a photovoltaic module, a multilayer film, a back sheet for a photovoltaic module, a manufacturing method thereof, and a photovoltaic module including the same.

Recently, interest in renewable energy and clean energy due to global environmental problems and depletion of fossil fuels has been growing, and among them, solar energy is notable as a representative pollution-free energy source that can solve environmental pollution problem and fossil fuel depletion problem. .

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, unit, and these units are referred to as photovoltaic modules.

Generally, a photovoltaic module uses a backsheet having excellent weather resistance and durability so that photovoltaic cells can be stably protected even when exposed to an external environment for a long period of time. Such a backsheet is generally formed by laminating a resin layer containing a fluororesin such as PVF (polyvinyl fluoride) on a substrate.

The fluororesin used for the backsheet can be roughly divided into a thermoplastic fluororesin and a thermosetting fluororesin. Examples of the thermoplastic fluororesins include PVDF (polyvinylidene fluoride) produced by Solvay, Arkema and Kureha, and polyvinyl fluoride (PVF) produced by Dupont. Examples of the thermosetting resin include Lumiflon ^TM ), Zeffle ^TM (Daikin), Fluorolink ^TM (Solvay), and Eterflon ^TM (Eternal).

As a method of forming a resin layer containing a fluorine resin on a substrate, a method of preparing a resin suspension or a solution containing mainly a fluorine resin and coating it on a substrate may be used.

Currently, a method of forming a resin layer on a substrate using a thermosetting fluorine resin mainly involves a method of coating a substrate with a coating liquid containing a thermosetting fluorine resin and a crosslinking agent, followed by drying. However, this method is disadvantageous in that when the thermosetting fluororesin and the cross-linking agent are mixed, the pot life (pot life) becomes short, the viscosity of the varnish rapidly increases and gels within a few hours. The viscosity of the thermosetting fluororesin and the crosslinking agent is rapidly increased within a short period of time. Therefore, the mixing and storage conditions of the thermosetting fluororesin and the crosslinking agent are limited, and the coating process must be performed immediately after mixing the thermosetting fluororesin and the crosslinking agent. However, if the coating process is performed immediately after the mixing process, since the bubbles in the varnish produced in the mixing process are not fully defoamed, bubbles are formed during the coating process, and pin holes or A lot of voids can be formed.

Further, when the coating process is stopped for changing process conditions such as temperature, the process can not easily change the process conditions because the varnish is gelled immediately. In addition, according to the above-mentioned method, it is impossible to store the remaining varnish after the coating process, so that the waste of the raw material can be increased.

In order to solve this problem, in WO 2008/143719, a thermosetting fluororesin and a crosslinking agent are separately supplied to a mixer via two pipes, varnish is produced in the mixer, and a coating process is immediately performed And the like. However, since the varnish produced in the mixing process is directly used in the coating process even in the case of the above-mentioned process equipment, formation of pin holes or voides in the coating film due to bubbles can not be avoided, At the end of the process, the varnish still remaining in the mixer can easily gel.

As a result, it is possible to prevent the gelation of the varnish produced by mixing the thermosetting fluororesin and the crosslinking agent, thereby improving the pot life of the varnish, and without changing the process conditions, and securing the properties of a superior coating film It is necessary to develop a resin composition for a photovoltaic module which is excellent in adhesion to a substrate.

The present invention provides a resin composition for a photovoltaic module, a multilayer film, a method of manufacturing the same, a back sheet for a photovoltaic module, and a photovoltaic module including the same.

One embodiment of the present invention provides a resin composition for a photovoltaic module comprising a thermosetting fluororesin and a blocked crosslinking agent.

Another embodiment of the present invention is directed to an article comprising: a substrate; And a resin layer formed on the substrate and including a cured product of the resin composition for a photovoltaic module according to the present invention.

Another embodiment of the present invention provides a method for producing a multilayered film comprising forming a resin layer containing a cured product of a resin composition for a photovoltaic module according to the present invention on a substrate.

Another embodiment of the present invention provides a backsheet for a photovoltaic module comprising a multilayer film according to the present invention.

Another embodiment of the present invention provides a photovoltaic module comprising a backsheet for a photovoltaic module according to the present invention.

The present invention relates to a resin composition for a photovoltaic module, and a resin composition for a photovoltaic module of the present invention includes a thermosetting fluorine resin containing a hydroxyl group and a blocked crosslinking agent, so that the pot life of the varnish is improved, There is no restriction on the modification of the process conditions. When the resin composition of the present invention is coated on a substrate and then dried, the curing reaction is not abruptly performed, so that generation of pin holes or voids is small, It is possible to maintain an excellent adhesive strength. In addition, the resin composition for a photovoltaic module of the present invention can be coated on a substrate in a one-part system, and the manufacturing cost can be reduced since no additional equipment is required in the two-part system.

1 is a cross-sectional view of a multilayer film according to an embodiment of the present invention.
Figures 2 and 3 are cross-sectional views of photovoltaic modules in accordance with various embodiments of the present invention.

The present invention relates to a resin composition for a photovoltaic module comprising a thermosetting fluororesin and a blocked crosslinking agent.

The thermosetting fluororesin contained in the resin composition of the present invention contains a hydroxyl group as a functional group. The hydroxy group may allow the thermosetting fluorine resin to cause a crosslinking reaction with a crosslinking agent to be described later to cure the resin composition of the present invention.

In the present invention, the thermosetting fluororesin may be a copolymer containing a hydroxy group in the main chain or side chain, and may be a copolymer of an ethylene compound containing a hydroxy group and at least one fluororesin. The type of the fluororesin that can be included in the thermosetting fluororesin is not particularly limited and includes, for example, vinylidene fluoride (VDF), vinyl fluoride (VF), tetrafluoroethylene (TFE) Tetrafluoroethylene, hexafluoropropylene (HFP), chlorotrifluoroethylene (CTFE), trifluoroethylene, hexafluoroisobutylene, perfluorobutylethylene, perfluoromethyl vinyl ether (PMVE perfluoro (methylvinylether), perfluoro (ethylvinylether), perfluoropropyl vinyl ether (PPVE), perfluorohexyl vinyl ether (PHVE), perfluoro-2,2- Dimethyl-1,3-dioxol (PDD) or perfluoro-2-methylene-4-methyl-1,3-dioxolane (PMD), for example tetrafluoroethylene.

In the resin composition for a photovoltaic module of the present invention, the blocked crosslinking agent may be contained in an amount of 0.5 to 1.5 equivalents relative to 1 equivalent of the hydroxyl group of the above-mentioned thermosetting fluororesin, for example, 0.8 to 1.2 equivalents or 0.9 equivalents to 1.1 Equivalent ratio. That is, the functional group (for example, an isocyanate group) of the crosslinking agent may have an equivalent ratio of the hydroxyl group of the thermosetting fluororesin of 0.5: 1 to 1.5: 1. By adjusting the content of the blocked crosslinking agent to the above range, it is possible to prevent uncured, adjust the curing time appropriately, prevent the residual of the unreacted curing agent to prevent the deterioration of the adhesion due to the residual curing agent, It is possible to prevent the occurrence of bubbles in the same severe condition.

The type of the blocked cross-linking agent is not particularly limited. For example, an isocyanate-based compound blocked with a blocking agent may be mentioned. The blocked isocyanate compound has a form in which a blocking agent is bonded to the terminal of an isocyanate group (-N = C = O) of an isocyanate compound, and the reaction between the isocyanate group and the hydroxyl group at room temperature can be blocked by the blocking agent .

However, when the blocked isocyanate compound is heated at a certain temperature, that is, at a temperature above the temperature at which the blocking agent is dissociated, the blocking agent bound to the terminal of the isocyanate group may dissociate and the isocyanate group may exist in a state capable of binding with another functional group .

When the blocked isocyanate compound is used as the blocked crosslinking agent, the type of the isocyanate compound is not particularly limited as long as it is a non-yellowing type having excellent weatherability. For example, a compound having two or more isocyanate groups in one molecule Lt; / RTI > That is, it is not suitable to include an aromatic compound as the non-yellowing type isocyanate compound capable of preventing the yellowing phenomenon.

Specific examples of the isocyanate compound include: Aliphatic diisocyanates such as hexamethylene diisocyanate (HMDI), 4,4'-dihexylmethane diisocyanate (H ₁₂ MDI), and dimer acid diisocyanate; Or cycloaliphatic diisocyanates such as isophorone diisocyanate (IPDI), cyclohexane diisocyanate (CHDI), and hydrogenated xylene diisocyanate (H ₆ XDI) , Preferably isocyanate compounds of non-yellowing type such as IPDI, HMDI, H ₁₂ MDI and H ₆ XDI, but are not limited thereto.

Examples of the crosslinking agent containing an aromatic compound which is not suitable for the resin composition for a photovoltaic module of the present invention include toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), xylene diisocyanate diisocyanate, XDI), and aromatic diisocyanates such as naphthalene diisocyanate (NDI). Aromatic dian cyanate is vulnerable to ultraviolet rays, so that the aromatic double bonds may break and yellowing may occur.

The type of blocking agent that can be used to block the crosslinking agent is not particularly limited and may be selected from the group consisting of phenols, oximes, active methylenes,? -Caprolactams, triazoles, and pyrazoles blocking agents And one or more selected from the group consisting of MEKO (methylethyl ketoxime), DMP (3,5-dimethyl pyrazole), DEM (diethyl malonate) and mixtures thereof.

The resin composition for a photovoltaic module of the present invention includes a blocked crosslinking agent, and at room temperature, the crosslinking agent does not undergo a crosslinking reaction with a thermosetting fluorine resin containing a hydroxyl group by a block agent, and can be stored in a one- have.

After the resin composition for a photovoltaic module of the present invention is coated on a substrate, it is dried at a temperature higher than the temperature at which the block agent dissociates through, for example, MEKO (methylethyl ketoxime) at 140 to 160 ° C, DMP pyrazole) and 100 占 폚 to 120 占 폚 or more in the case of diethyl malonate (DEM) to dissociate the blocking agent bound to the crosslinking agent, thereby crosslinking the crosslinking agent and the thermosetting fluororesin A fluororesin layer can be formed.

As described above, the resin composition for a photovoltaic module of the present invention is a one-pack type resin composition which does not progress to gelation at room temperature and requires no additional equipment compared with the two-pack type resin composition, there is no restriction on the change of the process condition due to the long pot life, and since the curing reaction is not abruptly carried out during the drying process, a pin hole or void (or a pinhole) in the fluorine resin layer containing the cured product of the resin composition void) can be reduced.

The resin composition for a photovoltaic module of the present invention may further comprise at least one additive selected from the group consisting of pigments, fillers, ultraviolet stabilizers and heat stabilizers.

The pigment or filler may be used together with the above-described thermosetting fluororesin and blocked crosslinking agent for the purpose of controlling the color or opacity of the resin composition for photovoltaic modules of the present invention or for other purposes. Examples of pigments or fillers which can be used in the present invention, metal oxides such as titanium dioxide (TiO _2), silica and alumina; Black pigments such as calcium carbonate, barium sulfate and carbon black; Or a pigment component showing a different color, but the present invention is not limited thereto. The above pigment or filler has a unique effect of controlling the hue and opacity of the resin composition for a photovoltaic module of the present invention and the cured product of the resin composition for a photovoltaic module of the present invention May further improve the adhesion of the fluororesin layer to the substrate.

The ultraviolet light stabilizer and heat stabilizer are used to improve the durability of the fluorine resin layer containing the cured product of the resin composition for a photovoltaic module of the present invention. The kind of the ultraviolet light stabilizer and heat stabilizer is not particularly limited, Can be adopted without.

Another embodiment of the present invention relates to a multilayer film. A multilayer film according to one embodiment of the present invention comprises a substrate; And a fluororesin layer formed on the substrate and including a cured product of the resin composition for a photovoltaic module according to the present invention described above.

FIG. 1 is a cross-sectional view of a multilayer film according to an embodiment of the present invention. Referring to FIG. As shown in Figure 1, the multilayer film 10 of the present invention comprises a substrate 12; And a fluororesin layer 11 formed on the base material 12 and containing a cured product of the resin composition for a photovoltaic module described above.

The specific type of the substrate included in the multilayered film of the present invention is not particularly limited as long as it includes at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amine group and an amino group on the surface of the substrate, And can be appropriately selected and used according to the required functions and applications.

In the present invention, for example, various polymer films can be used as the substrate. Examples of the polymer film include a single sheet such as an acrylic film, a polyolefin film, a polyamide film, a polyurethane film, and a polyester film, a laminated sheet, or a pneumatic article, and a polyester film is generally used , But 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 polybutylene terephthalate (PBT) film But is not limited thereto.

Further, as the polyester film, one having excellent moisture-decomposing properties may be used. The polyester film having excellent hydrolysis resistance is preferably a polyester film having a small content of oligomers generated during the condensation polymerization. Further, the polyester film may be further subjected to a heat treatment for improving the moisture-decomposing property known in the art, so that the water content of the polyester can be reduced and the shrinkage ratio can be reduced, thereby further improving the moisture resistance. It is also possible to use a commercially available product as a film excellent in water-decomposing properties.

In the present invention, in order to further improve the adhesion with a fluorine resin layer to be described later, a high-frequency spark discharge treatment such as a corona treatment or a plasma treatment is applied to one surface or both surfaces of a substrate; Heat treatment; Flame treatment; Anchor treatment; Coupling agent treatment; Surface treatment such as primer treatment or chemical activation treatment using gaseous Lewis acid (ex. BF ₃ ), sulfuric acid or high temperature sodium hydroxide can be performed. The surface treatment method may be performed by any known means generally used in this field.

In the present invention, the surface treatment as described above can induce a hydroxyl group, a carboxyl group, an amine group, an amino group, an aromatic thiol group, or the like on the surface of a substrate to improve the bonding property with a crosslinking agent contained in the fluorine resin layer, The bonding force can be further improved.

In the present invention, an inorganic oxide deposited layer may be formed on one side or both sides of the substrate to improve the moisture barrier property. The kind of the inorganic oxide is not particularly limited and can be adopted without limitation as long as it has moisture barrier properties. In the present invention, for example, silicon oxide or aluminum oxide may be used as the inorganic oxide, but the present invention is not limited thereto. The method for forming an inorganic oxide deposit layer on one side or both sides of the substrate in the present invention is not particularly limited and may be a deposition method generally used in this field.

In the case of forming the inorganic oxide deposit layer on one side or both sides of the substrate in the present invention, the above-mentioned surface treatment can be performed on the inorganic oxide deposit layer after the inorganic oxide deposit layer is formed on the substrate surface.

In the present invention, the thickness of the substrate is not particularly limited, and may be, for example, in the range of 50 탆 to 500 탆, or in the range of 100 탆 to 300 탆. By controlling the thickness of the base material as described above, it is possible to maintain excellent electrical insulation, moisture barrier properties, mechanical properties, handling properties, and the like of the multilayer film. However, the thickness of the substrate in the present invention is not limited to the above-mentioned range, and it can be suitably adjusted as required.

The multilayer film of the present invention includes a fluororesin layer formed on the substrate and containing the cured product of the resin composition for a photovoltaic module according to the present invention described above. The fluorine resin layer contains a cured product of the resin composition for a photovoltaic module as described above, so that the adhesive strength to the substrate can be improved. The details of the resin composition for a photovoltaic module are the same as those described above, so that a description thereof will be omitted.

In the multilayered film of the present invention, the thickness of the fluororesin layer is not particularly limited, and may be, for example, 3 탆 to 50 탆, or 10 탆 to 30 탆. If the thickness of the fluororesin layer is less than 3 탆, the fluororesin layer is too thin, filling of the filler is insufficient, and light diffusibility may be lowered. If the thickness exceeds 50 탆, the production cost may increase.

In the multilayer film of the present invention, the fluororesin layer is a coating layer. The term " coating layer " used in the present invention means a resin layer formed by a coating method. More specifically, the " coating layer " is a method in which a fluororesin layer containing a cured product of the resin composition for a photovoltaic module is laminated by using a casting method or an extrusion method on a substrate using an adhesive or the like Refers to a case where the resin composition or coating solution for a photovoltaic module prepared by dissolving a component constituting the fluororesin layer in a solvent, preferably a solvent having a low boiling point, is coated on a substrate.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a multilayer film 10 according to one embodiment of the present invention. And a fluororesin layer 11 formed only on one side of the substrate 12, the multilayered film (not shown) according to another embodiment of the present invention may have a fluororesin layer formed on the other side of the substrate And a fluororesin layer formed on both sides of the substrate.

Further, the multilayer film of the present invention may further include various functional layers known in the art, if necessary. Examples of the functional layer include an adhesive layer and an insulating layer. For example, in the multilayered film of the present invention, the above-mentioned fluorine resin layer may be formed on one side of the substrate, and an adhesive layer and an insulating layer may be sequentially formed on the other side. The adhesive layer or insulating layer may be formed in a variety of ways known in the art. For example, the insulating layer may be 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) not only functions as an insulating layer but also improves adhesion to an encapsulant and enables reduction of manufacturing cost, and re-workability ) Can be performed at the same time.

Another embodiment of the present invention relates to a method for producing a multilayered film comprising forming a fluororesin layer containing a cured product of a resin composition for a photovoltaic module according to the present invention described above on a substrate.

The method of forming the fluororesin layer on the substrate in the present invention is not particularly limited. For example, a resin composition for a photovoltaic module or a coating solution prepared by dissolving or dispersing the above-mentioned thermosetting fluororesin and a blocked crosslinking agent in an appropriate organic solvent is coated on a substrate in accordance with various methods known in the art After that, the fluororesin layer can be formed by a method such as drying under a predetermined condition.

The coating method is not particularly limited. For example, a well-known printing method such as an offset printing method and a gravure printing method, a well-known coating method such as a roll coating, a knife edge coating and a gravure coating, Any method capable of forming a coating layer is applicable. In the present invention, various methods known in the art may be applied in addition to the above-mentioned methods, and the resin composition or coating solution for the photovoltaic module may further include various other additives as required.

The specific types of the substrate that can be used in the manufacturing method of the present invention are as described above. On one side or both sides of the substrate, appropriate deposition treatment, plasma treatment, corona treatment, anchorage treatment, coupling agent treatment, And a treatment may be carried out before the formation of the fluororesin layer, or a substrate on which the surface treatment has already been carried out may be used.

In the present invention, the coating liquid for forming the resin layer, that is, the resin composition for a photovoltaic module, is prepared by dissolving or dispersing each component forming the resin layer in a solvent having a relatively low boiling point, specifically a solvent having a boiling point of 200 ° C or less . That is, in the present invention, the fluorine resin is mixed with the blocked cross-linking agent, so that it can be effectively dissolved in a solvent having a relatively low boiling point. Accordingly, the present invention does not require a high-temperature drying step in the production process, thereby reducing manufacturing cost, preventing thermal deformation and thermal shock of the substrate, which may be caused during high-temperature drying, .

Examples of the solvent which can be used in the present invention include a solvent selected from the group consisting of acetone, methyl ethyl ketone (MEK), isobutyl ketone (MIBK), ethyl acetate (EA), toluene, xylene However, the present invention is not limited thereto.

The solvent such as acetone, methyl ethyl ketone, isobutyl ketone, toluene or xylene is a solvent which evaporates at a temperature of 200 ° C or lower. In addition to being able to dissolve the above-mentioned thermosetting fluororesin and blocked crosslinking agent well, And then dried at a relatively low temperature.

In the case of the blocked crosslinking agent, the blocking agent is dissociated from the crosslinking agent at a temperature not lower than a certain temperature through a drying process, and various functional groups present on the surface of the substrate through the functional group at the terminal of the crosslinking agent, for example, an isocyanate group, such as a hydroxyl group, An amine group, an amino group, or the like. Accordingly, the multilayered film can improve the bonding force between the crosslinking agent of the fluororesin layer and the functional groups on the surface of the substrate, thereby further improving the adhesion between the substrate and the fluororesin layer.

In the present invention, the resin composition for a photovoltaic module used for forming the fluororesin layer may further contain various additives such as a pigment, a filler, a UV stabilizer or a heat stabilizer in addition to the thermosetting fluororesin and the blocked crosslinking agent. Each of the above additives may be dissolved in a solvent together with a fluorine resin and a blocked crosslinking agent or may be prepared in the form of a mill base separately from the above components and then mixed with a solvent containing the thermosetting fluorine resin and the blocked crosslinking agent . Chemical interactions such as van der Waals bond, hydrogen bond, ionic bond, or covalent bond may also be caused by the functional group contained in the additive such as pigment or filler which may be contained in the resin layer, And the substrate can be further improved.

In the present invention, a method for producing a resin composition for a photovoltaic module, a ratio of each component contained in the resin composition for a photovoltaic module, and the like are not particularly limited, and various methods known in the art can be suitably employed.

In the method for producing a multilayer film of the present invention, the step of forming the fluororesin layer may include: coating the resin composition for a photovoltaic module according to the present invention on a substrate; And drying the coated substrate coated with the resin composition for the photovoltaic module. The conditions for the drying are not particularly limited as long as the condition that the blocking agent can dissociate and is, for example, at a temperature of 200 DEG C or less or 150 DEG C to 180 DEG C for 30 seconds to 30 minutes, preferably 1 minute to 10 minutes ≪ / RTI > In the present invention, by performing the drying process under the above-described conditions, it is possible to prevent an increase in manufacturing cost due to the high-temperature drying process of 200 ° C or more, and to prevent deterioration of product quality due to thermal deformation or thermal shock.

In the method for producing a multilayered film of the present invention, the block agent is dissociated by a drying process, and then a curing reaction of the fluorine resin layer occurs at room temperature. Further, a post-curing process may be performed at about 40 to 60 ° C.

The method for producing a multilayered film using the resin composition for a photovoltaic module according to the present invention is a one-pack type method in which the resin composition for a photovoltaic module is not gelated at room temperature, It does not require any additional equipment, unlike the two-part system. In addition, since the curing reaction is not rapidly performed after coating the resin composition for a photovoltaic module on a base material, the resin layer containing the cured product of the resin composition has a pin hole ) Or the number of voids can be reduced and the adhesion with the substrate can be further improved.

The present invention also relates to a backsheet for a photovoltaic module comprising the multilayer film according to the present invention described above.

As described above, the backsheet for a photovoltaic module includes a fluororesin layer containing a cured product of the resin composition for a photovoltaic module according to the present invention, and the cross-linking agent contained in the resin layer has various functional groups By forming a chemical bond between the hydroxyl groups of the thermosetting fluororesin, it is possible to provide excellent adhesion between the substrate and the resin layer.

Specifically, the interface between the resin layer and the substrate during the manufacturing process of the backsheet for the photovoltaic module; Or the fluorine resin contained in the resin layer and the crosslinking agent form a chemical bond with the surface of the base material or the surface treatment layer of the base material at the interface between the resin layer and the surface treatment layer of the base material, The adhesive strength can be improved.

The present invention also relates to a photovoltaic module including the backsheet for a photovoltaic module according to the present invention described above.

The structure of the photovoltaic module of the present invention is not particularly limited as long as it includes the multilayer film as a back sheet for a photovoltaic module, and various structures commonly known in this field can be employed without limitation.

In the present invention, for example, the structure of the photovoltaic module includes a back sheet; A photovoltaic cell or a photovoltaic array formed on the backsheet; A light-receiving sheet formed on the photovoltaic cell or the photovoltaic array; And an encapsulant layer which encapsulates the photovoltaic cell or photovoltaic array between the backsheet and the light-receiving sheet.

The thickness of the backsheet is not particularly limited. For example, the thickness of the backsheet may be in the range of 30 占 퐉 to 2,000 占 퐉, 50 占 퐉 to 1,000 占 퐉, or 100 占 퐉 to 600 占Lt; / RTI > In the present invention, by controlling the thickness of the backsheet within the range of 30 탆 to 2,000 탆, properties such as weather resistance of the photovoltaic module can be maintained excellent while the photovoltaic module is made thinner.

In the present invention, the specific type of photovoltaic cells formed on the backsheet is not particularly limited as long as it can generate photovoltaic power, and photovoltaic devices generally used in this field can be used. In the present invention, for example, an amorphous silicon photocatalyst such as a single crystal silicon, a crystalline silicon photocell such as polycrystalline silicon, a single coupled type or a tandem structure type, a gallium-arsenic (GaAs) III-V compound semiconductor photovoltaic cells such as InP and II-VI compound semiconductor photodiodes such as cadmium-tellurium (CdTe) and copper-indium-selenide (CuInSe ₂ ) A film polycrystalline silicon photovoltaic cell, a thin film amorphous silicon photovoltaic cell, and a hybrid photocell of thin film crystalline silicon and amorphous silicon.

In the present invention, the photovoltaic cell can form a photovoltaic array (photovoltaic assembly) by wiring connecting the photovoltaic cell and the photovoltaic cell. When sunlight is irradiated to the photovoltaic module of the present invention, electrons (-) and holes (+) are generated inside the photovoltaic cell, and current flows through the wiring connecting the photovoltaic cell and the photovoltaic cell.

In the present invention, the light-receiving sheet formed on the photovoltaic cell or the photovoltaic array can function to protect the inside of the photovoltaic module from rain, external impact, fire or the like, and to secure long-term reliability when the photovoltaic module is exposed to the outside . The specific type of the light-receiving sheet of the present invention is not particularly limited as long as it is excellent in light transmittance, electrical insulation, mechanical or physical and chemical strength, and examples thereof include glass plates, fluororesins, polycarbonates Based resin sheet, a poly (meth) acrylic resin sheet, a polyamide-based resin sheet, or a polyester-based resin sheet. In the present invention, it is preferable to use a glass plate having excellent heat resistance, but the present invention is not limited thereto.

The thickness of the light-receiving sheet used in the present invention is not particularly limited, and may be, for example, 0.5 mm to 10 mm, 1 mm to 8 mm, or 2 mm to 5 mm. In the present invention, by controlling the thickness of the light-receiving sheet within the range of 0.5 mm to 10 mm, physical properties such as long-term reliability of the photovoltaic module can be kept excellent while the photovoltaic module is made thinner.

The encapsulant layer for encapsulating the photovoltaic cell or the photovoltaic cell array in the interior of the photovoltaic module of the present invention, specifically between the backsheet and the light-receiving sheet, can be employed without limitation as an encapsulating material generally known in the field.

2 and 3 are cross-sectional views of a photovoltaic module according to various embodiments of the present invention.

FIG. 2 is a view showing an embodiment of a wafer-based photovoltaic module 20 including a back sheet for a photovoltaic module of the present invention. 2, the photovoltaic module according to an exemplary embodiment of the present invention typically includes a light-receiving sheet 21, which may be formed of a ferroelectric (e.g., glass); A back sheet (23) for a photovoltaic module according to the present invention; A photovoltaic device 24 such as a silicon wafer; And an encapsulant layer 22 that encapsulates the photovoltaic device 24. The encapsulant layer 22 encapsulates the photovoltaic device 24 and encapsulates the first layer 22a and the photovoltaic device 24 adhered to the light-receiving sheet 21, And a second layer 22b attached to the second layer 22b. In the present invention, the first layer 22a and the second layer 22b constituting the encapsulant layer 22 may be composed of a material generally known in this field as described above, and for example, , Ethylene vinyl acetate (EVA), but are not limited thereto.

FIG. 3 is a cross-sectional view of a thin-film photovoltaic module 30 according to another embodiment of the present invention. 3, in the case of the thin-film photovoltaic module 30, the photovoltaic device 34 may be formed on the light-receiving sheet 31, which may be typically formed of a ferroelectric. Such a thin film photovoltaic device 34 may be deposited by a method such as chemical vapor deposition (CVD). The attached photovoltaic module 30 of FIG. 3 includes a light receiving sheet 31, a photovoltaic device 34, an encapsulant layer 32 and a back sheet 33 similar to the photovoltaic module 20 of FIG. 2, The encapsulant layer 32 may be a single layer. The light-receiving sheet 31, the photovoltaic device 34, the encapsulant layer 32, and the backsheet 33 are described above in detail.

In the present invention, the method for manufacturing the above-described photovoltaic module is not particularly limited, and various methods known to those skilled in the art may be employed without any limitations.

The photovoltaic module shown in FIGS. 2 and 3 is only one example of various embodiments of the photovoltaic module of the present invention. If the backsheet for a photovoltaic module according to the present invention is included, the structure of the photovoltaic module, The type and size of the material constituting the substrate are not particularly limited and those generally known in this field can be employed without limitation.

Hereinafter, the present invention will be described in more detail with reference to the following examples and comparative examples, but the scope of the present invention is not limited by the following examples.

The physical properties of the films prepared in Examples and Comparative Examples were measured in the following manner.

1. housework time ( pot life )

The resin composition for a photovoltaic module manufactured in Examples and Comparative Examples was measured for time change to increase the viscosity to twice or more the initial viscosity. The storage stability and the storage stability of the resin composition for a photovoltaic module can be evaluated through the change of the viscosity with time.

2. cross - Hatch adhesion

A crosscut test was performed in accordance with the standard of ASTM D3002 / D3359, which is a crosscut test standard. Specifically, the specimens were cut into 11 squares in the horizontal and vertical directions at intervals of 1 mm, and 100 square squares with 1 mm width and 1 mm squared were formed. Then, when the CT-24 adhesive tape of Nichiban Co., Ltd. was attached to the cut surface and then removed, the state of the falling surface was measured and evaluated based on the following criteria.

≪ Cross-hatch adhesion evaluation standard >

5B: When there is no falling side

4B: If the distance between the sides is less than 5% of the total area

3B: When the distance from the surface is 5% to 15% of the total area

2B: When the distance is more than 15% to 35% of the total area

1B: When the distance is more than 35% to 65% of the total area

0B: When the distance is more than 65% of the total area

3. Moisture ( damp heat ) Test

The multilayer film (one side of the substrate coated with a resin layer containing a fluorine resin and a crosslinking agent) prepared in Examples and Comparative Examples was placed in an oven maintained at 85 ° C and 85% RH for 1,000 hours, 2,000 hours, and 3,000 hours The adhesive strength was observed after standing. In this specification, the unit "RH" means relative humidity.

4. PCT ( pressure cooker test )

The multilayer film (one side of the substrate coated with a resin layer containing a fluorine resin and a crosslinking agent) prepared in Examples and Comparative Examples was placed in an oven maintained at 2 atm, 121 ° C and 100% RH for 25 hours, 50 hours and After standing for 75 hours, the change in adhesive strength was observed.

5. Sulfur modification

UV irradiating the Examples and the Comparative Examples A multi-layer film (coating the surface of the substrate with the resin layer containing a fluorine-based resin and a cross-linking agent) manufactured from 60 ℃, ultraviolet radiation intensity of ^{0.77 W / m 2 (340 nm} ) (QUV, Q-Lab Co., Ltd.) for 1000 hours. Thereafter, the yellow index of the multilayer film was measured with a colorimeter (UV-3600, manufactured by Shimadzu Corp.) using a C light source and Observer 2 (ASTM D1925).

Example  One

Preparation of equipment

The surface of a PET (poly (ethylene terephthalate), thickness: 250 占 퐉) film (made by Kolon) treated with acrylic primer on both sides was subjected to corona treatment.

Formation of fluorine resin layer

100 parts by weight of Zeffle GK-570 was added to 100 parts by weight of Zeffle GK-570 (Daikin, solid content 60%, 60 mgKOH / g) which is a copolymer of tetrafluoroethylene (TFE) and ethylene substituted with a hydroxyl group as a thermosetting fluororesin 35.7 parts by weight of isophorone diisocyanate blocked with MEKO (methylethyl ketoxime) as a crosslinking agent (equivalent ratio of OH in Zeffle GK-570 to NCO of crosslinking agent = 1: 1) and 60 parts by weight of titanium dioxide (TiPure TS6200, DuPont) , 10 parts by weight of methyl ethyl ketone was further added, and the mixture was sufficiently stirred to prepare a coating solution for forming a fluororesin layer.

The coating liquid for forming the fluororesin layer was coated on one surface of a substrate prepared in advance by a comma reverse method. Specifically, the coated substrate was coated with a thickness of about 10 mu m after drying, and then the coated substrate was coated on each of the three substrates having a length of 2 m and a temperature of 80 DEG C, 180 DEG C, and 180 DEG C in three ovens m / min to form a fluororesin layer. Subsequently, the substrate laminated with the fluororesin layer was aged at room temperature for one week to prepare a multilayer film having a fluororesin layer coated on one side of the substrate (PET film).

Example  2

In the preparation of the coating liquid for forming the fluororesin layer, instead of using 35.7 parts by weight of isophorone diisocyanate blocked with MEKO as a crosslinking agent, 29.8 parts by weight of isophorone diisocyanate blocked with DMP (3,5-dimethylpyrazole) (Zeffle GK- A multilayer film was prepared in the same manner as in Example 1, except that the equivalent ratio of OH in 570 to NCO in the crosslinking agent was 1: 1.

Example  3

26 parts by weight of hexamethylene diisocyanate blocked with DMP (3,5-dimethylpyrazole) (Zeffle GK-570 (trade name, available from Dow Corning Toray Co., Ltd.) instead of using 35.7 parts by weight of isophorone diisocyanate blocked with MEKO as a cross- And the equivalent ratio of NCO in the cross-linking agent = 1: 1) was used as the cross-linking agent.

Example  4

In the preparation of the coating liquid for forming a fluororesin layer, 31.4 weight parts of hexamethylene diisocyanate blocked with DMP (3,5-dimethylpyrazole) and DEM (diethyl malonate) were used instead of 35.7 parts by weight of isophorone diisocyanate blocked with MEKO as a cross- (Equivalent ratio of OH in Zeffle GK-570 to NCO of cross-linking agent = 1: 1) was used in place of the cross-linking agent.

Comparative Example  One

In the preparation of the coating solution for forming a fluororesin layer, 35.7 parts by weight of isophorone diisocyanate blocked with MEKO as a crosslinking agent was used, and 25.1 parts by weight of unblocked isophorone diisocyanate (equivalent ratio of OH in Zeffle GK-570 to NCO of crosslinking agent = 1: 1) was used instead of the polyimide film.

Comparative Example  2

In the preparation of the coating liquid for forming the fluorine resin layer, instead of using 35.7 parts by weight of isophorone diisocyanate blocked with MEKO as a cross-linking agent, 13.6 parts by weight of unblocked hexamethylene diisocyanate (equivalent ratio of OH in Zeffle GK-570 to NCO = 1: 1) was used instead of the polyimide film.

Comparative Example  3 to 4

In the preparation of the coating liquid for forming a fluororesin layer, instead of using 35.7 parts by weight of isophorone diisocyanate blocked with MEKO as a crosslinking agent, 22.2 parts by weight of toluene diisocyanate (equivalent ratio of OH in Zeffle GK-570 to NCO of crosslinking agent = 1: 1) and 25.1 parts by weight of diphenylmethane diisocyanate (equivalent ratio of OH of crosslinking agent to NCO of Zeffle GK-570 = 1: 1) was used as a crosslinking agent.

Comparative Example  5

A multilayer film was produced in the same manner as in Example 1, except that a stainless steel sheet was used instead of the PET film as the base material.

The compositions of the fluororesin layer-forming coating liquids prepared in the above Examples and Comparative Examples are summarized in Tables 1 and 2 below.

division Example Comparative Example One 2 3 4 One 2 3 4 5 Zeffle GK-570 100 100 100 100 100 100 100 100 100 Cross-linking agent A 35.7 - - - - - - - 35.7 B - 29.8 - - - - - - - C - - 26 - - - - - - D - - - 31.4 - - - - - E - - - - 25.1 - - - - F - - - - - 13.6 - - - G - - - - - - 22.2 - - H - - - - 25.1 - TiPure TS6200 80 80 80 80 80 80 80 80 80 Content Unit: parts by weight

Cross-linking agent NCO type Blocking topic NCO (%) A Isophorone diisocyanate MEKO 8.1% B Isophorone diisocyanate DMP 8.7% C Hexamethylene diisocyanate DMP 11.1% D Hexamethylene diisocyanate DMP + DEM 9.2% E Isophorone diisocyanate - 11.9% F Hexamethylene diisocyanate - 21.25% G Toluene diisocyanate - 13% H Diphenylmethane diisocyanate - 11.5%

Experimental Example  One

The multilayer films prepared in Examples 1 to 4 and Comparative Examples 1 to 5 were subjected to a pressure cooker test and a damp heat test, respectively, and then subjected to a cross-hatch test. Specifically, each of the multilayer films was allowed to stand for 25 hours, 50 hours, and 75 hours at 2 atm, 121 ° C, and 100% R.H., respectively, and then the cross-hatch test was performed to evaluate the change in the adhesion. Further, each of the multilayer films was allowed to stand in an oven maintained at 85 캜 and 85% RH for 1,000 hours, 2,000 hours and 3,000 hours, and then the cross-hatch test was performed to observe a change in the adhesive force. The evaluation results are shown in Table 3 below.

After performing the PCT,
Cross-hatch test results After performing the damp heat test,
Cross-hatch test results Early 25 H 50 H 75 H Early 1000 H 2000 H 3000 H Example One 5B 5B 5B 5B 5B 5B 5B 5B 2 5B 5B 4B 4B 5B 5B 4B 4B 3 5B 5B 4B 4B 5B 5B 4B 4B 4 5B 5B 5B 5B 5B 5B 5B 5B Comparative Example One 5B 5B 2B 0B 5B 4B 1B 0B 2 5B 4B 0B 0B 5B 4B 0B 0B 3 5B 4B 0B 0B 5B 4B 0B 0B 4 5B 4B 0B 0B 5B 4B 0B 0B 5 5B 3B 0B 0B 5B 2B 0B 0B H: Time

As shown in Table 3, in the examples according to the present invention, the fluororesin layer of the multilayered film includes a cured product of a coating liquid containing a thermosetting fluororesin and a blocked crosslinking agent, , It exhibited excellent adhesion even after 75 hours of PCT and showed excellent adhesion even after 3000 hours of damp heat.

On the other hand, in the comparative example not in accordance with the present invention, the curing reaction is initiated before the fluorine resin layer is coated due to the coating liquid containing the crosslinking agent in which the fluorine resin layer of the multilayer film is not blocked, As a result, the adhesive strength to the substrate was significantly decreased while the PCT proceeded, and the adhesive strength to the substrate was remarkably decreased as the sample was allowed to stand for at least 1000 hours even under damp heat conditions.

When the fluororesin layer was coated on the stainless steel sheet instead of the PET film as the substrate, the initial adhesion was good, but the adhesion was remarkably decreased under PCT and humid conditions.

Experimental Example  2

The multilayer films prepared in Examples 1 to 4 and Comparative Examples 1 to 5 were subjected to pressure cooker test and damp heat test, respectively, and then subjected to interfacial peeling and pinhole formation in the fluororesin layer The changes in appearance were observed. Specifically, each of the multilayer films was allowed to stand under the conditions of 2 atm, 121 캜 and 100% RH for 25 hours, and then the change in appearance was visually observed. Each multilayer film was allowed to stand in an oven maintained at 85 캜 and 85% RH for 1,000 hours, and then the appearance of the multilayer film was visually observed. The above observation results are shown in Table 4 below.

division Example Comparative Example One 2 3 4 One 2 3 4 5 Appearance change After PCT Good Good Good Good Bubble occurrence Bubble occurrence Bubble occurrence Bubble occurrence Bubble occurrence After the wet heat test Good Good Good Good Good Good Good Good Good PCT run time: 25 hours
Heat test time: 1000 hours
Good: No visible change in the surface of resin layer of multilayer film
Bubble generation: Bubbles observed with the naked eye on the surface of the resin layer of the multilayer film

As shown in Table 4, in the examples according to the present invention, the fluororesin layer of the multilayered film contains a cured product of the coating liquid containing the thermosetting fluororesin and the blocked crosslinking agent, so that even after the PCT test or the wet heat test, The appearance change on the surface of the fluororesin layer of the film was not visually observed. On the other hand, in the comparative example not in accordance with the present invention, bubble formation on the surface of the fluororesin layer of the multilayered film was observed visually as the PCT proceeded due to the coating solution containing the crosslinking agent in which the fluororesin layer of the multilayered film was not blocked. As described above, the bubble generation was observed only in the resin layer of the multilayered film of the comparative example because the pinhole or void portion already formed in the coating process was gradually adhered This is because the moisture penetrates into the region as the region becomes weak.

That is, since Examples 1 to 4 according to the present invention include a cross-linking agent blocked when coating the fluorine resin layer, the curing reaction does not occur rapidly during coating and drying of the coating liquid for forming a fluorine resin layer on the substrate, The formation of holes or voids is suppressed and good adhesion is maintained even under PCT or wet heat test conditions. On the other hand, in the coating and drying processes on the substrate using Comparative Examples 1 to 4 including an unblocked crosslinking agent, The pinholes or voids are better formed, and the decrease in the adhesion force under PCT or wet heat conditions is greater.

Further, in the case of Comparative Example 5 in which a fluorine resin layer was coated on a stainless steel sheet instead of a PET film as a substrate, since adhesion was not sufficient under PCT or wet heat conditions, moisture easily penetrated into the interface After the PCT, bubble generation on the surface of the fluorine resin layer was visually observed.

Experimental Example  3

In order to examine the pot life of the fluororesin layer-forming coating liquid prepared in Examples 1 to 4 and Comparative Examples 1 to 5, the initial viscosity of the coating liquid for forming each fluororesin layer was at least 2 times And the time taken for the increase. Further, while the storage time of the coating liquid for forming a fluororesin layer was changed to 1 hour, 2 hours, 4 hours, 1 day, 7 days, and 30 days, the coating liquid for forming a fluororesin layer After the multilayer film was produced, the above-described cross-hatch test was performed. Table 6 shows the measured time of use and cross-hatch test results of the measured coating liquid for fluororesin layer formation.

division Example Comparative Example One 2 3 4 One 2 3 4 5 Housework time More than 30 days More than 30 days More than 30 days 5 days Less than 4 hours Less than 2 hours Less than 4 hours Less than 4 hours More than 30 days Cross-hatch test results Immediately after manufacture 5B 5B 5B 5B 5B 5B 5B 5B 5B Storage 1 hour 5B 5B 5B 5B 4B 4B 4B 4B 5B Storage 2 hours 5B 5B 5B 5B 3B Gelling 3B 3B 5B Storage 4 hours 5B 5B 5B 5B Gelling Gelling Gelling Gelling 5B Storage 1 day 5B 5B 5B 5B Gelling Gelling Gelling Gelling 5B Storage 7 days 5B 5B 5B Gelling Gelling Gelling Gelling Gelling 5B Storage 30 days 5B 5B 5B Gelling Gelling Gelling Gelling Gelling 5B Pot life: The time taken for the viscosity of the resin composition to increase more than twice as much as the initial viscosity
Storage time: The time for which the resin composition is left after the production of the multilayered film using the resin composition
Gelation: When the resin composition is hardened and has no fluidity

As shown in Table 5, in the examples according to the present invention, the coating liquid for forming a fluororesin layer contains a thermosetting fluororesin and a blocked crosslinking agent, and the usable time, which is usable time, was 30 days or more. In the comparative example which does not follow, the coating solution for forming a fluororesin layer contains a crosslinking agent which is not blocked, so that it has a pot life of 4 hours or less.

In Examples according to the present invention, the coating liquid for forming a fluororesin layer was allowed to stand for one day or more and then used in the production of a multilayer film to maintain an excellent adhesive force. On the other hand, in Comparative Examples 1 to 4 , And when the coating solution for forming a fluororesin layer is left for 4 hours or less, gelation proceeds and it can not be used.

That is, since the coating liquid for forming a fluororesin layer according to the present invention contains a blocked crosslinking agent, the crosslinking reaction does not proceed even if left at room temperature for a long time, and thus it is easy to store and to have excellent storage stability.

Experimental Example  4

The multilayer films prepared in Examples 1 to 4 and Comparative Examples 1 to 5 were subjected to ultraviolet stability test (QUV test) and damp heat test, respectively, and yellow index was measured. Specifically, each multilayered film was allowed to stand at a temperature of 60 ° C and a condition of 0.77 W / m ² for 1000 hours, and then subjected to a cross-hatch test to evaluate the change in adhesive force. Each of the multilayer films was allowed to stand in an oven maintained at 85 ° C and 85% RH for 1,000 hours, 2,000 hours and 3,000 hours, and then the yellow index of the multilayer film was measured with a color meter (UV-3600, Observer 2 was measured with C light source using Shimadzu). Each of the multilayer films was allowed to stand in an oven under the conditions of 85 ° C and 85% RH for 1000 hours, and then the yellow index of the multilayer film was measured using a color meter (UV-3600, Shimadzu) Observer 2 was measured as a light source. The evaluation results are shown in Table 6 below.

After performing UV stability test,
Sulfur denaturation measurement result After performing the damp heat test,
Sulfur denaturation measurement result Early 1000 H Early 1000 H Example One -6.51 -6.7 -6.51 -6.62 2 -6.98 -6.52 -6.98 -6.07 3 -6.22 -5.81 -6.22 -6.12 4 -6.34 -6.26 -6.34 -5.76 Comparative Example One -6.7 -6.22 -6.7 -6.23 2 -7.03 -6.95 -7.03 -6.59 3 -6.26 5.68 -6.26 -5.36 4 -6.67 5.79 -6.67 -5.76 5 -6.72 -6.35 -6.72 -5.78 H: Time

As shown in Table 6, in the case of the multilayer film of the examples according to the present invention, the sulfur modification was hardly changed even after the ultraviolet stability test or the wet heat test was carried out by including the crosslinking agent composed of aliphatic monomers. However, in the case of Comparative Examples 3 and 4 not in accordance with the present invention, when the crosslinking agent containing an aromatic compound is included in the ultraviolet stability test, the aromatic double bond is broken by ultraviolet rays, and yellowing is observed.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be appreciated that other embodiments are possible. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10: multilayer film
11: Fluorine resin layer
12: substrate
20: Wafer-based photovoltaic module
30: Thin-film photovoltaic module
21, 31: Light receiving sheet
22, 32:
22a: First layer
22b: second layer
23, 33:
24, 34: photovoltaic device

Claims (20)

Polymer film substrates; And
(VF), vinyl fluoride (VF), tetrafluoroethylene (TFE), hexafluoropropylene (HFP), hexafluoropropylene, chlorotriene Perfluoroethyl vinyl ether (PEVE), perfluoroethyl vinyl ether (PMVE), perfluoroethyl vinyl ether (PEVE), perfluoroethyl vinyl ether perfluoro (ethylvinylether), perfluoropropyl vinyl ether (PPVE), perfluorohexyl vinyl ether (PHVE), perfluoro-2,2-dimethyl-1,3-dioxole -2-methylene-4-methyl-1,3-dioxolane (PMD) and an ethylene compound containing a hydroxyl group, a thermosetting fluorine resin having a boiling point of 200 ° C or lower Point solvent and a block-zero blocked isocyanate compound such that the isocyanate group of the blocked isocyanate compound is 0.5 to 1.5 equivalents based on 1 equivalent of the hydroxyl group of the thermosetting fluororesin. The fluorine-containing resin composition for a photovoltaic module A multi-layer film comprising a resin layer. delete delete delete The method according to claim 1,
Wherein the block agent is at least one selected from the group consisting of phenols, oximes, active methylenes,? -Caprolactams, triazoles, and pyrazole blocking agents. The method according to claim 1,
Wherein the block agent is at least one selected from the group consisting of MEKO (methylethyl ketoxime), DMP (3,5-dimethyl pyrazole) and DEM (diethyl malonate). The method according to claim 1,
The resin composition for a photovoltaic module further comprises at least one additive selected from the group consisting of pigments, fillers, ultraviolet stabilizers, and heat stabilizers. delete delete The method according to claim 1,
Wherein the substrate comprises at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amine group and an amino group on the surface. The method according to claim 1,
The polymer film may be an acrylic film, a polyolefin film, a polyamide film, a polyurethane film, a polyester film, a polyethylene terephthalate (PET) film, a polyethylene naphthalate (PEN) film and a polybutylene terephthalate ≪ / RTI > The method according to claim 1,
Wherein at least one treatment selected from a plasma treatment, a corona treatment, a primer treatment, an anchor treatment, a coupling agent treatment, and a heat treatment is formed on one side or both sides of the substrate. The method according to claim 1,
A multilayer film in which an inorganic oxide vapor deposition layer is formed on one side or both sides of the substrate. The method according to claim 1,
Wherein the thickness of the substrate is from 50 mu m to 500 mu m. The method according to claim 1,
Wherein the fluororesin layer has a thickness of 3 占 퐉 to 50 占 퐉. (VF), vinyl fluoride (VF), vinyl fluoride (VF), tetrafluoroethylene (TFE), hexafluoropropylene (HFP) and hexafluoropropylene), chlorotrifluoroethylene Perfluoro (methylvinylether), perfluoroethyl vinyl ether (PEVE, perfluoro (methyl vinyl ether)), perfluoro (methyl vinyl ether), perfluoro perfluorohexyl vinyl ether (PHVE), perfluoro-2,2-dimethyl-1,3-dioxole (PDD), and perfluoro-2 -Methylene-4-methyl-1,3-dioxolane (PMD) and an ethylene compound containing a hydroxyl group, a low-boiling point A solvent and a block-blocked isocyanate compound such that the isocyanate group of the blocked isocyanate compound is 0.5 to 1.5 equivalents based on 1 equivalent of the hydroxyl group of the thermosetting fluororesin. And forming a stratum. delete 17. The method of claim 16,
A step of performing at least one surface treatment selected from the group consisting of a plasma treatment, a corona treatment, a primer treatment, an anchor treatment, a coupling agent treatment, a vapor deposition treatment and a heat treatment is applied to one surface or both surfaces of the substrate before forming the fluororesin layer By weight based on the total weight of the film. A backsheet for a photovoltaic module comprising the multilayer film according to claim 1. 20. A photovoltaic module comprising a backsheet for a photovoltaic module according to claim 19.

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