KR101191126B1 - Encapsulant sheet, preparation method thereof, and photovoltaic module comprising the same - Google Patents

Abstract

The present invention relates to a solar cell encapsulant sheet, a method for manufacturing the same, and a solar cell module including the same, wherein the solar cell module is easily formed and has excellent thermal stability, transparency, and electrical insulation. More specifically, the encapsulant sheet may include 1) an ultra low density ethylene-alpha olefin copolymer, 2) a low density ethylene-alpha olefin copolymer, and 3) a silane graft-modified ultra low density ethylene-alpha olefin copolymer. It includes. The encapsulant sheet according to the present invention is not only excellent in thermal stability, transparency, electrical insulation, but also excellent in adhesiveness with a solar cell module member.

Encapsulant Sheet, Solar Cell Module

Description

Encapsulant sheet, manufacturing method thereof, and solar cell module including same {ENCAPSULANT SHEET, PREPARATION METHOD THEREOF, AND PHOTOVOLTAIC MODULE COMPRISING THE SAME}

The present invention relates to an encapsulant sheet having excellent thermal stability, transparency, electrical insulation, adhesiveness with a solar cell module member, a manufacturing method thereof, and a solar cell module including the same.

Photovoltaic power generation is an infinite, clean power generation technology that generates electricity from sunlight. Solar cells (modules) that generate electricity by receiving sunlight, power control devices that convert generated DC electricity into alternating current, and electricity generated during the day It consists of a storage battery and the like. The module that generates electricity consists of glass, encapsulant, solar cell, and backsheet. In general, glass, which is a surface material, requires low iron tempered glass to have high light transmittance and to be treated to reduce surface light reflection loss. As a solar cell, crystalline silicon solar cell is currently used in the entire solar cell market. It occupies more than 90% of the market, and research is being actively conducted on low cost, high efficiency, and thin film-type solar cells. Since the crystalline silicon has a weak rigidity, there is a risk of breaking at a small impact, it is important to develop an encapsulant having excellent impact resistance.

EVA (ethylene-vinylacetate copolymer), which is currently used as an encapsulant, is a material inserted between the front and rear surfaces of the solar cell and the surface material to protect the fragile solar cell device. However, when the EVA sheet is exposed to ultraviolet rays for a long time, problems such as discoloration and poor moisture resistance may occur. In addition, the EVA sheet does not have sufficient adhesive strength with the tempered glass substrate in the solar cell element, and peeling phenomenon occurs due to long-term use, or vinyl acetate gas is generated during heating, causing odor and electrode damage or foaming. There is a problem such as becoming.

Accordingly, there is a need in the art for development of an encapsulant having excellent transparency, electrical insulation properties, and the like, and excellent adhesion to a solar cell module member.

An object of the present invention is to provide a solar cell module encapsulant sheet excellent in transparency, electrical insulation, adhesiveness with a solar cell module member, and the like.

In addition, an object of the present invention is to provide a solar cell module comprising the solar cell module encapsulant sheet manufacturing method and the solar cell module encapsulant sheet.

The present invention,

1) an ethylene-alpha olefin copolymer having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5 and a density of 0.85 to 0.89 g / cc,

2) an ethylene-alphaolefin copolymer having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5 and a density of greater than 0.89 g / cc and less than 0.92 g / cc, and

3) A silane graft modified ethylene-alpha olefin copolymer comprising an ethylene-alpha olefin copolymer having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5 and a density of 0.85 to 0.89 g / cc and a silane compound. An encapsulant sheet comprising a blend resin is provided.

In addition,

a) an ethylene-alpha olefin copolymer having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5 and a density of 0.85 to 0.89 g / cc, 2) a molecular weight distribution (Mw / Mn) of 1.5 to 3.5 and a density of Ethylene-alphaolefin copolymers greater than 0.89 g / cc and less than 0.92 g / cc, and 3) ethylene-alphaolefin copolymers and silanes having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5 and a density of 0.85 to 0.89 g / cc. Preparing a blend resin composition comprising a silane graft-modified ethylene-alpha olefin copolymer comprising a system compound, and

b) forming a sheet using the blend resin composition

It provides a method for producing an encapsulant sheet comprising a.

In addition, the present invention provides a solar cell module including the encapsulant sheet.

The encapsulant sheet and the solar cell module including the same according to the present invention include an ultra low density ethylene-alpha olefin copolymer, a low density ethylene-alpha olefin copolymer, and a blend resin of a silane graft modified ultra low density ethylene-alpha olefin copolymer. By doing so, transparency is improved, and electrical insulation properties can be improved by providing excellent thermal stability and moisture barrier property compared to existing EVA, and can provide excellent adhesiveness with a solar cell module member.

Hereinafter, the present invention will be described in detail.

The encapsulant sheet according to the present invention has 1) an ethylene-alpha olefin copolymer having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5, a density of 0.85 to 0.89 g / cc, and 2) a molecular weight distribution (Mw / Mn) of 1.5. Ethylene-alpha olefin copolymer having a density of ~ 3.5 and a density of more than 0.89 g / cc and less than 0.92 g / cc, and 3) an ethylene- having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5 and a density of 0.85 to 0.89 g / cc. It is characterized by comprising a blend resin comprising a silane graft modified ethylene-alpha olefin copolymer comprising an alpha olefin copolymer and a silane compound.

In the encapsulant sheet according to the present invention, the 1) ethylene-alpha olefin copolymer is an ultra low density ethylene-alpha olefin copolymer having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5 and a density of 0.85 to 0.89 g / cc. It is characterized by that. In addition, the melt index (MI) of the 1) ultra low density ethylene-alpha olefin copolymer is preferably 0.2 to 40 g / 10 min, but is not limited thereto.

1) The ultra low density ethylene-alpha olefin copolymer may be an ultra low density ethylene-alpha olefin copolymer satisfying the following formula (1).

Re × Rc ≤ 1.00

In Equation 1, Re and Rc are each a ratio of reactivity of an ethylene monomer (e: ethylene) and a comonomer (c: comonomer), and are defined as Re = kee / kec and Rc = kcc / kce, where kec is The growth reaction rate constant when the comonomer is added to the growth chain where the terminal active point is the ethylene monomer, kee is the growth reaction rate constant when the ethylene monomer is added to the growth chain where the terminal active point is ethylene monomer, kce is the terminal activity The point is the growth reaction rate constant when the ethylene monomer is added to the growth chain of the comonomer, and kcc is the growth reaction rate constant when the comonomer is added to the growth chain of the terminal active point.

Re and Rc of Equation 1 can be obtained by measuring the arrangement of monomers through C13 NMR.

It is known that alternating copolymers can be formed when Re × Rc <1.0, and block copolymers are formed when Re × Rc> 1.0. The above formula may be a copolymer in which three or more comonomers are not continuously polymerized, and characterizes the polymer in which the comonomer is evenly distributed in the polymer backbone. The evenly distributed comonomers may improve physical properties by increasing a uniform reaction and reaction efficiency when preparing the silane-modified resin.

In the encapsulant sheet according to the present invention, the 1) ultra-low density ethylene-alpha olefin copolymer has excellent transparency, but has a low density and a melting temperature of 80 ° C. or less. As described above, the low melting point of the ultra low density ethylene-alpha olefin copolymer may cause a sticky problem in forming the encapsulant sheet.

Therefore, the present invention blends the 2) ethylene-alpha olefin copolymer to 1) ultra low density ethylene-alpha olefin copolymer to solve this problem.

2) The ethylene-alpha olefin copolymer is a low density ethylene-alpha olefin copolymer, characterized in that the molecular weight distribution (Mw / Mn) is 1.5 ~ 3.5, the density is more than 0.89 g / cc less than 0.92 g / cc. In addition, the melt index (MI) of the low density ethylene-alpha olefin copolymer 2 is preferably 0.2 to 40 g / 10 min, and the melting temperature is preferably more than 80 ° C. and 120 ° C. or less, but is not limited thereto.

In the encapsulant sheet according to the present invention, the 1) ultra low density ethylene-alpha olefin copolymer and 2) low density ethylene-alpha olefin copolymer are prepared using a catalyst composition comprising a transition metal compound represented by the following Chemical Formula 1 Can be.

In Formula 1,

R1 and R2 may be the same or different from each other, and each independently hydrogen; Halogen radicals; An alkyl radical having 1 to 20 carbon atoms; An alkenyl radical having 2 to 20 carbon atoms; An aryl radical having 6 to 20 carbon atoms; Silyl radical; An alkylaryl radical having 7 to 20 carbon atoms; An arylalkyl radical having 7 to 20 carbon atoms; Or a metalloid radical of a Group 4 metal substituted with hydrocarbyl; R 1 and R 2 or two R 2 may be connected to each other by an alkylidine radical including an alkyl having 1 to 20 carbon atoms or an aryl radical having 6 to 20 carbon atoms to form a ring;

R 3 may be the same as or different from each other, and each independently hydrogen; Halogen radicals; An alkyl radical having 1 to 20 carbon atoms; An alkenyl radical having 2 to 20 carbon atoms; An aryl radical having 6 to 20 carbon atoms; An alkylaryl radical having 7 to 20 carbon atoms; An arylalkyl radical having 7 to 20 carbon atoms; An alkoxy radical having 1 to 20 carbon atoms; An aryloxy radical having 6 to 20 carbon atoms; Or amido Radical; Two or more R3 in said R3 may be connected to each other to form an aliphatic ring or an aromatic ring;

CY1 is a substituted or unsubstituted aliphatic or aromatic ring, and the substituents substituted in CY1 are halogen radicals; An alkyl radical having 1 to 20 carbon atoms; An alkenyl radical having 2 to 20 carbon atoms; An aryl radical having 6 to 20 carbon atoms; An alkylaryl radical having 7 to 20 carbon atoms; An arylalkyl radical having 7 to 20 carbon atoms; An alkoxy radical having 1 to 20 carbon atoms; An aryloxy radical having 6 to 20 carbon atoms; Or an amido radical, and when there are a plurality of substituents, two or more substituents in the substituents may be linked to each other to form an aliphatic or aromatic ring;

M is a Group 4 transition metal;

Q1 and Q2 may be the same as or different from each other, and each independently a halogen radical; An alkyl radical having 1 to 20 carbon atoms; An alkenyl radical having 2 to 20 carbon atoms; An aryl radical having 6 to 20 carbon atoms; An alkylaryl radical having 7 to 20 carbon atoms; An arylalkyl radical having 7 to 20 carbon atoms; An alkylamido radical having 1 to 20 carbon atoms; An arylamido radical having 6 to 20 carbon atoms; Or an alkylidene radical having 1 to 20 carbon atoms.

The transition metal compound may be a transition metal compound represented by the following Chemical Formula 2 or 3 as the compounds of Formula 1 that are more preferred for controlling the electronic and three-dimensional environment around the metal.

In Chemical Formulas 2 and 3,

R4 and R5 may be the same as or different from each other, and each independently hydrogen; Halogen radicals; An alkyl radical having 1 to 20 carbon atoms; An aryl radical having 6 to 20 carbon atoms; Or a silyl radical;

R6 may be the same as or different from each other, and each independently hydrogen; Halogen radicals; An alkyl radical having 1 to 20 carbon atoms; An alkenyl radical having 2 to 20 carbon atoms; An aryl radical having 6 to 20 carbon atoms; An alkylaryl radical having 7 to 20 carbon atoms; Arylalkyl radicals having 7 to 20 carbon atoms; An alkoxy radical having 1 to 20 carbon atoms; An aryloxy radical having 6 to 20 carbon atoms; Or amido radicals; Two or more R6 in said R6 may be linked to each other to form an aliphatic or aromatic ring;

Q3 and Q4 may be the same as or different from each other, and each independently a halogen radical; An alkyl radical having 1 to 20 carbon atoms; An alkylamido radical having 1 to 20 carbon atoms; Or an aryl amido radical having 6 to 20 carbon atoms;

M is a Group 4 transition metal.

In Chemical Formula 1, more preferred compounds for controlling the electronic steric environment around the metal include transition metal compounds having the following structure.

In the above formula,

R 7 may be the same or different from each other, and each independently selected from hydrogen or methyl radicals,

Q5 and Q6 may be the same as or different from each other, and are each independently selected from a methyl radical, a dimethylamido radical, or a chloride radical.

The catalyst composition including the transition metal compound represented by Chemical Formula 1 may include one or more of the cocatalyst compounds represented by the following Chemical Formula 4, 5 or 6.

-[Al (R8) -O] _n-

In Chemical Formula 4,

R8 may be the same or different from each other, and each independently halogen; Hydrocarbons having 1 to 20 carbon atoms; Or a hydrocarbon having 1 to 20 carbon atoms substituted with halogen;

n is an integer of 2 or more;

D (R8) ₃

In Formula 5,

R8 is as defined in Formula 4 above;

D is aluminum or boron;

[LH] ⁺ [ZA ₄ ] ^- or [L] ⁺ [ZA ₄ ] ^-

In Formula 6,

L is a neutral or cationic Lewis acid;

H is a hydrogen atom;

Z is a Group 13 element;

A may be the same as or different from each other, and independently at least one hydrogen atom is an aryl group having 6 to 20 carbon atoms or an alkyl group having 1 to 20 carbon atoms substituted or unsubstituted with halogen, hydrocarbon having 1 to 20 carbon atoms, alkoxy or phenoxy .

Examples of the compound represented by the formula (4) include methyl aluminoxane, ethyl aluminoxane, isobutyl aluminoxane, butyl aluminoxane and the like, and more preferred compound is methyl aluminoxane.

Examples of the compound represented by Formula 5 include trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, tripropyl aluminum, tributyl aluminum, dimethylchloro aluminum, triisopropyl aluminum, tri-s-butyl aluminum, tricyclopentyl aluminum , Tripentyl aluminum, triisopentyl aluminum, trihexyl aluminum, trioctyl aluminum, ethyl dimethyl aluminum, methyl diethyl aluminum, triphenyl aluminum, tri-p-tolyl aluminum, dimethyl aluminum methoxide, dimethyl aluminum ethoxide, trimethyl Boron, triethylboron, triisobutylboron, tripropylboron, tributylboron, and the like, and more preferred compounds are selected from trimethylaluminum, triethylaluminum and triisobutylaluminum.

Examples of the compound represented by Formula 6 include triethylammonium tetraphenylboron, tributylammonium tetraphenylboron, trimethylammonium tetraphenylboron, tripropylammonium tetraphenylboron, trimethylammonium tetra (p-tolyl) Boron, trimethylammonium tetra (o, p-dimethylphenyl) boron, tributylammonium tetra (p-trifluoromethylphenyl) boron, trimethylammonium tetra (p-trifluoromethylphenyl) boron, tributylammonium tetra Pentafluorophenylboron, N, N-diethylanilinium tetraphenylboron, N, N-diethylanilinium tetrapentafluorophenylboron, diethylammonium tetrapentafluorophenylboron, triphenylphosphonium Tetraphenylboron, trimethylphosphonium tetraphenylboron, triethylammonium tetraphenylaluminum, tributylammonium tetraphenylaluminum, trimethylammonium tetraphenylaluminum, Tripropylammonium tetraphenylaluminum, trimethylammonium tetra (p-tolyl) aluminum, tripropylammonium tetra (p-tolyl) aluminum, triethylammonium tetra (o, p-dimethylphenyl) aluminum, tributylammonium Tetra (p-trifluoromethylphenyl) aluminum, trimethylammonium tetra (p-trifluoromethylphenyl) aluminum, tributylammonium tetrapentafluorophenylaluminum, N, N-diethylanilinium tetraphenylaluminum, N , N-diethylanilinium tetrapentafluorophenylaluminum, diethylammonium tetrapentatetraphenylaluminum, triphenylphosphonium tetraphenylaluminum, trimethylphosphonium tetraphenylaluminum, tripropylammonium tetra (p-tolyl) Boron, triethylammonium tetra (o, p-dimethylphenyl) boron, tributylammonium tetra (p-trifluoromethylphenyl) boron, triphenylcarbonium umtetra (p-triple -Phenyl) boron and the like, triphenylamine car I Titanium tetra-penta flow phenylboronic.

Among the cocatalyst compounds, the compounds represented by Formulas 4 and 5 may be represented by alkylating agents, and the compounds represented by Formula 6 may be represented by activators.

The catalyst composition is present in an activated state by a reaction between the transition metal compound represented by the formula (1) and the cocatalyst, which is also referred to as an activated catalyst composition. However, since it is known in the art that the catalyst composition remains in an activated state, the term activated catalyst composition is not used separately herein.

1) the ultra-low density ethylene-alpha olefin copolymer and 2) low-density ethylene-alpha olefin copolymer to prepare a catalyst composition using at least one cocatalyst of the compound represented by Formula 1 and the compound represented by Formulas 4 to 6 It can then be prepared by polymerizing ethylene and alpha olefins using it. The catalyst composition may be prepared by the following method for producing a composition.

Firstly contacting the transition metal compound represented by Formula 1 with the compound represented by Formula 4 or Formula 5 to obtain a mixture; And adding a compound represented by Chemical Formula 6 to the mixture.

Second, a method of preparing a catalyst composition is provided by contacting a transition metal compound represented by Chemical Formula 1 with a compound represented by Chemical Formula 4.

In addition, a method of preparing a catalyst composition is provided by contacting a transition metal compound represented by Chemical Formula 1 with a compound represented by Chemical Formula 6.

In the case of the first method of preparing the catalyst composition, the molar ratio of the compound represented by Formula 4 or Formula 5 to the transition metal compound represented by Formula 1 is preferably 1: 2 to 1: 5,000, more preferably. Preferably 1:10 to 1: 1,000, and most preferably 1:20 to 1: 500. Next, the molar ratio of the compound represented by Formula 6 to the transition metal compound represented by Formula 1 is preferably 1: 1 to 1:25, more preferably 1: 1 to 1:10, and most preferably Is 1: 2 to 1: 5.

When the molar ratio of the compound represented by Formula 4 or Formula 5 to the transition metal compound represented by Formula 1 is less than 1: 2 in the first method of preparing a catalyst composition, the amount of alkylating agent is very small so that alkylation of the metal compound is completely There is a problem that does not proceed, if the exceeds 1: 5,000 alkylation of the metal compound is made, but due to the side reaction between the remaining excess alkylating agent and the activator of Formula 6 it is not fully activated the alkylated metal compound there is a problem. Next, when the ratio of the compound represented by Formula 6 to the transition metal compound represented by Formula 1 is less than 1: 1, the amount of the activator is relatively small so that the activation of the transition metal compound represented by Formula 1 is completely If there is a problem that the activity of the resulting catalyst composition is poor because it is not made and exceeds 1:25, the transition metal compound represented by Formula 1 is fully activated, but the remaining cost of the catalyst composition is economical due to excess activator. There is a problem that is not or the purity of the polymer produced.

In the second method of preparing the catalyst composition, the molar ratio of the compound represented by Formula 4 to the transition metal compound represented by Formula 1 is preferably 1:10 to 1: 10,000, more preferably 1: 100 to 1: 5,000, most preferably 1: 500 to 1: 2000.

When the molar ratio is less than 1:10, the amount of the activator is relatively small, and thus the activity of the catalyst composition generated due to the incomplete activation of the metal compound is inferior. When the molar ratio is greater than 1: 10,000, it is represented by Formula 1 Although the activation of the transition metal compound is completely made, there is a problem in that the cost of the catalyst composition is not economically reduced or the purity of the resulting polymer is low due to the excess activator remaining.

On the other hand, the molar ratio of the compound represented by the formula (6) to the transition metal compound represented by the formula (1) in the case of the third method of the catalyst composition preparation method is preferably 1: 1 to 1:25, more preferably 1: 1 to 1:10, most preferably 1: 2 to 1: 5. When the molar ratio of the compound represented by the formula (6) to the transition metal compound represented by the formula (1) is less than 1: 1, the amount of the activator is relatively small, so that the catalyst is not produced completely because the activation of the compound of the formula (1) When the activity of the composition is inferior, and when it exceeds 1:25, the metal compound is fully activated, but the excess amount of the activator does not allow the cost of the catalyst composition to be economical or the purity of the produced polymer is inferior. There is.

In addition, the transition metal compounds and cocatalysts represented by Chemical Formula 1 may be used in a form supported on silica or alumina.

In the polymerization method of 1) the ultra low density ethylene-alpha olefin copolymer and 2) the low density ethylene-alpha olefin copolymer, the catalyst composition may be a suitable aliphatic hydrocarbon solvent having 5 to 12 carbon atoms, for example, pentane, hexane and heptane. , Nonane, decane, and isomers thereof, and aromatic hydrocarbon solvents such as toluene and ben, and hydrocarbon solvents substituted with chlorine atoms such as dichloromethane and chlorobenzene may be dissolved or diluted. The solvent used herein is preferably used by removing a small amount of water, air or the like acting as a catalyst poison by treating a small amount of alkylaluminum, and may be carried out by further using a promoter.

Alphaolefin comonomers copolymerized with ethylene using the catalyst composition described above also include diene olefin monomers or triene olefin monomers having two or more double bonds. The alpha olefin comonomer is preferably a C ₃ to C ₂₀ alpha olefin. Specific examples of the alpha olefin comonomer include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1- Dodecene, 1-tetradecene, 1-hexadecene, 1-aitocene, norbornene, norbonadiene, ethylidenenorbornene, phenylnorbornene, vinylnorbornene, dicyclopentadiene, 1,4-butadiene, 1 , 5-pentadiene, 1,6-hexadiene, styrene, alpha-methylstyrene, divinylbenzene, 3-chloromethyl styrene, and the like. Two or more kinds of these monomers may be mixed and used. Propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1 More preferably at least one olefin selected from the group consisting of hexadecene and 1-atocene, selected from the group consisting of propylene, 1-butene, 1-hexene, and 4-methyl-1-pentene, and 1-octene It is preferred, and even more preferably 1-octene. At this time, it is particularly preferable to use n-hexane as the polymerization solvent.

As a polymerization process of said 1) ultra low density ethylene-alpha olefin copolymer and 2) low density ethylene-alpha olefin copolymer, the solution process using the said catalyst composition is the most preferable. When the catalyst composition is used together with an inorganic carrier such as silica, the catalyst composition can be applied to a slurry or gas phase process.

The reactor used in the polymerization process of 1) the ultra low density ethylene-alpha olefin copolymer and 2) the low density ethylene-alpha olefin copolymer is preferably a continuous stirred reactor (CSTR) or a continuous flow reactor (PFR). In the production process of the above 1) ultra low density ethylene-alpha olefin copolymer and 2) low density ethylene-alpha olefin copolymer, it is preferable that at least two reactors are arranged in series or in parallel. In addition, the production process of the 1) ultra low density ethylene-alpha olefin copolymer and 2) low density ethylene-alpha olefin copolymer preferably further includes a separator for continuously separating the solvent and unreacted monomer from the reaction mixture.

In the above 1) ultra low density ethylene-alpha olefin copolymer and 2) low density ethylene-alpha olefin copolymer, the molar ratio of ethylene to alpha olefin comonomer is 100: 1 to 1: 100, preferably 10: 1 to 1 : 10, most preferably 2: 1 to 1: 5. When the molar ratio of ethylene to alpha olefin comonomer exceeds 100: 1, the density of the produced polymer may increase, which may cause difficulty in preparing a low density polymer, and the mole ratio of ethylene to alpha olefin comonomer may occur. When the amount exceeds 1: 100, the amount of unreacted comonomer increases, the conversion rate decreases, and consequently, a process recycle may occur.

The molar ratio of monomer to solvent suitable for the reaction should be a ratio suitable for dissolving the raw material before the reaction and the polymer produced after the reaction. Specifically, the molar ratio of monomer to solvent is 10: 1 to 1: 10000, preferably 5: 1 to 1: 100, most preferably 1: 1 to 1:20. When the molar ratio of the monomer to the solvent is less than 10: 1, the amount of the solvent is too small to increase the viscosity of the fluid, which may cause a problem in the transfer of the resulting polymer, and the molar ratio of the monomer to the solvent is 1: 10000. If it exceeds, the amount of solvent is more than necessary, and thus problems such as equipment increase and energy cost increase due to the recirculation of the purification of the solvent may occur.

As described above, the molar ratio of ethylene to alpha olefin comonomer is appropriately adjusted so that 1) an ultra low density ethylene-alpha olefin copolymer having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5 and a density of 0.85 to 0.89 g / cc, And 2) low-density ethylene-alphaolefin copolymers having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5 and a density of more than 0.89 g / cc and less than 0.92 g / cc, respectively.

In the encapsulant sheet according to the present invention, the 3) silane graft modified ethylene-alpha olefin copolymer has an ethylene-alpha olefin having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5 and a density of 0.85 to 0.89 g / cc. It is characterized by including a copolymer and a silane compound.

In the encapsulant sheet according to the present invention, the silane-based compound of 3) is not particularly limited as long as it is graft-polymerized with the ultra low density ethylene-alpha olefin copolymer, and includes an ethylenically unsaturated hydrocarbon group and a hydrolyzable functional group. Preference is given to unsaturated silanes. For example, the silane which has functional groups, such as vinyl, acryl, amino, chloro, phenoxy, etc. is mentioned.

More specifically, ethylenically unsaturated silanes, such as vinyl trimethoxysilane, vinyl triethoxysilane, vinyl triacetoxysilane, (gamma) -methacryloxypropyl trimethoxysilane, and vinyl tris (2-methoxyethoxy) silane This is preferable, and vinyltrimethoxysilane which has a vinyl functional group in which graft reaction is most easy is especially preferable.

3) In the silane graft modified ultra-low density ethylene-alpha olefin copolymer, the content of the silane-based compound relative to the ultra-low density ethylene-alpha olefin copolymer is preferably 0.05 to 5.0 wt%, but is not limited thereto. .

The method for producing the silane graft-modified ultra low density ethylene-alpha olefin copolymer is not particularly limited, but the silane compound is graft-polymerized to the ultra low density ethylene-alpha olefin copolymer in the presence of a radical initiator, for example. Here's how.

More specifically, the liquid injection of 0.05-5.0 wt% of silane compound and 0.001-0.02 wt% of radical initiator while melt-mixing the ultra low density ethylene-alpha olefin copolymer which is nitrogen atmosphere in the twin screw extruder of 50-230 degreeC It can be prepared while feeding into a twin screw extruder with a pump and reacting extrusion.

The radical initiator may be suitably used a known compound and is not particularly limited, but preferred embodiments include benzoyl peroxide, di-t-butyl peroxide, azobisisobutyronitrile, t-butyl hydroperoxide, Dicumyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, t-butyl peroctoate, methyl ethyl ketone peroxide, 2,5-dimethyl-2,5-di (t-butyl peroxy) hexane, Lauryl peroxide, lupersol 101, percardox-14, and the like. Preferred radical initiators are lupersol 101, but the initiator can be used by changing the initiator according to the extrusion temperature.

In the encapsulant sheet according to the present invention, the content of the 1) ultra low density ethylene-alpha olefin copolymer is greater than 0 and 85 wt% or less, and the content of the 2) low density ethylene-alpha olefin copolymer is 10 to 90 wt%, And 3) The content of the silane graft modified ultra low density ethylene-alpha olefin copolymer is preferably 5 to 90 wt%, but is not limited thereto.

The encapsulant sheet according to the present invention may further include one or more additives selected from ultraviolet absorbers, light stabilizers, heat stabilizers, antioxidants, and the like.

As the ultraviolet absorber, 2-hydroxy-4-methoxybenzophenone, 2-2-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-4-carboxybenzophenone, 2- Benzophenone compounds such as hydroxy-4-N-octoxybenzophenone; Benzotriazole compounds such as 2- (2-hydroxy-3,5-di-t-butylphenyl) benzotriazole and 2- (2-hydroxy-5-methylphenyl) benzotriazole; Salicylic acid ester type compounds, such as phenyl salicylate and p-octylphenyl salicylate, etc. are mentioned, It is not limited to this. The amount of the ultraviolet absorber is preferably 0.05 to 1.0 wt%.

The light stabilizer may include a hindered amine compound, a piperidine compound, and the like, but is not limited thereto. The content of the light stabilizer is preferably 0.05 ~ 1.0 wt%.

The antioxidant may include a phenol compound, a phosphite compound, and the like, but is not limited thereto. The content of the antioxidant is preferably 0.1 to 0.5 wt%.

It is preferable that the thickness of the sealing material sheet which concerns on this invention is 0.2-0.8 mm. In addition, the transparency of the encapsulant sheet is preferably a value of 91% or more of the transmittance, and the moisture barrier property is 1.0 to 2.0 g / m ² ? It is preferable that it is 24hr.

In addition, the method for producing an encapsulant sheet according to the present invention includes a) 1) an ethylene-alpha olefin copolymer having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5 and a density of 0.85 to 0.89 g / cc, and 2) a molecular weight distribution. An ethylene-alphaolefin copolymer having a Mw / Mn of 1.5 to 3.5, a density of more than 0.89 g / cc and less than 0.92 g / cc, and 3) a molecular weight distribution (Mw / Mn) of 1.5 to 3.5, and a density of 0.85 to Preparing a blend resin composition comprising a silane graft modified ethylene-alpha olefin copolymer comprising an ethylene-alpha olefin copolymer and a silane-based compound of 0.89 g / cc, and b) a sheet using the blend resin composition It characterized in that it comprises a step of forming.

In the manufacturing method of the encapsulant sheet according to the present invention, the ultra-low density ethylene-alpha olefin copolymer, low-density ethylene-alpha olefin copolymer, silane graft modified ultra-low density ethylene-alpha olefin copolymer and the like Since the same, specific details thereof will be omitted.

In the manufacturing method of the encapsulant sheet according to the present invention, the blend resin composition of step a) may further include one or more additives selected from ultraviolet absorbers, light stabilizers, heat stabilizers, antioxidants and the like.

In the manufacturing method of the encapsulant sheet according to the present invention, the step of forming the sheet in step b) may use a reaction extrusion process using a twin screw extruder capable of liquid injection. At this time, the temperature may be in the range of 50 ~ 230 ℃. In addition, the addition amount of a silane type compound can also add 2 to 4 times additionally according to the grafting efficiency of a silane. The silane graft modified ultra low density ethylene-alpha olefin copolymer obtained in this process and the silane unmodified ultra low density ethylene-alpha olefin and low density ethylene-alpha olefin copolymer are introduced together with additives in a single screw to twin screw extruder, A sheet may be formed through the die. In addition to the above method using an extruder and a T-die, it is also possible to form a sheet by calendering.

In addition, the present invention provides a solar cell module including the encapsulant sheet.

In the solar cell module according to the present invention, the solar cell cells arranged in series or in parallel are filled with an encapsulant sheet according to the present invention, and a glass surface is disposed on a surface hitting sunlight, and a rear surface is protected by a back sheet. It may have, but is not limited thereto.

One cross section of the solar cell module according to the present invention is shown in FIG. 1.

The back sheet is a weather resistant film that protects the back surface of the solar cell module from the outside. Specific examples thereof include metal plates or metal foils such as aluminum, fluorine resin sheets, cyclic olefin resin sheets, polycarbonate resin sheets, poly (meth) acrylic resin sheets, polyamide resin sheets, polyester resin sheets, and weather resistant films. And the composite sheet which laminated | stacked and barrier film, etc. are mentioned, It is not limited to this.

The solar cell module may be manufactured by a method known in the art, except for including the encapsulant sheet according to the present invention.

The encapsulant sheet according to the present invention is not only excellent in transparency, but also moisture barrier by using an ultra low density ethylene-alpha olefin copolymer, a low density ethylene-alpha olefin copolymer, a silane graft modified ultra low density ethylene- alpha olefin copolymer. It is excellent in the property and excellent in adhesiveness with the solar cell module member. In addition, the encapsulant sheet according to the present invention does not require a separate curing process, unlike the conventional EVA sheet, it is excellent in the production speed and production efficiency of the solar cell module.

In addition, the present invention is 1) the ethylene-alpha olefin copolymer having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5, the density of 0.85 to 0.89 g / cc, 2) the molecular weight distribution (Mw / Mn) of 1.5 to 3.5 Ethylene-alphaolefin copolymers having a density greater than 0.89 g / cc and less than 0.92 g / cc, and 3) an ethylene-alphaolefin air having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5 and a density of 0.85 to 0.89 g / cc. Provided is a resin composition comprising a silane graft modified ethylene-alphaolefin copolymer comprising a copolymer and a silane compound.

In the resin composition according to the present invention, the ultra low density ethylene-alpha olefin copolymer, low density ethylene-alpha olefin copolymer, silane graft-modified ultra low density ethylene-alpha olefin copolymer, etc. are the same as described above. Detailed description thereof will be omitted.

As described above, the resin composition according to the present invention is excellent in transparency by using an ultra low density ethylene-alpha olefin copolymer, a low density ethylene-alpha olefin copolymer, a silane graft modified ultra low density ethylene- alpha olefin copolymer. In addition, the encapsulant sheet having excellent moisture barrier property and excellent adhesion to the solar cell module member may be manufactured.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are intended to illustrate the invention and are not intended to limit the scope of the invention by the following examples.

< Example >

< Manufacturing example  1 and 2 and Comparative Production Example  1> Ethylene- Alphaolefin  Copolymer production

Hexane solvent, 1-octene and ethylene monomer were fed to a 1.5 L continuous stirred reactor preheated to 100-150 ° C. at a pressure of 89 bar. 0.40 μmol / min of the compound represented by Chemical Formula 1 and 0.60 μmol / min of the octadecylmethylammonium tetrakis (pentafluorophenyl) borate cocatalyst represented by Chemical Formula 1 were supplied from the catalyst storage tank to the reactor to proceed with the copolymerization reaction. The polymerization was carried out at a relatively high temperature of 140 ~ 180 ℃, the polymer solution formed by the copolymerization reaction was reduced to 7bar at the rear end of the reactor, and then sent to a solvent separator preheated to 190 ^° C to transfer most of the solvent to the solvent separation process By removal. The process is sent to the second separator by a pump, in which 100 ~ 2,000ppm of antioxidant Iganox 1076 in a weight ratio of the copolymer was dissolved in a hexane solvent and introduced into a liquid phase. The copolymer to which the antioxidant was added was transferred to a twin screw extruder equipped with a vacuum pump to completely remove the residual solvent, and then granulated into pellets to obtain a granulated polymer.

Specific conditions of the preparation composition of the ultra low density ethylene alpha olefin copolymer of Preparation Example 1 and the low density ethylene alpha olefin copolymer of Preparation Example 2 and Comparative Preparation Example 1 are shown in Table 1 below. The density, molecular weight distribution (PDI), etc. of the ethylene-alpha olefin copolymer prepared above were measured and shown in Table 1 below.

(1) Density: measured by ASTM D792 method

(2) Melt index (MI _{2 .16} ): measured using ASTM D1238 method

(3) Molecular weight distribution (PDI = Mw / Mn): measured using high temperature GPC (PL-GPC220)

(4) Monomer Reactivity Ratio: Measured by 13C-NMR (Frequency: 150MHz, Temp: 100 ° C, D1 = 0.5 to 1 sec, Scans = 50k, 5mm tube, WALTZ decoupling, Solvent: TCE-d2 / TCB (2: 1) ), Measured under conditions of 0.05M Chromium acetylacetonate)

From the results of Table 1, it can be seen that the ethylene-alpha olefin copolymer according to the present invention implements low density and ultra low density, and has a narrow molecular weight distribution, high molecular weight, and evenly distributed dispersion of alpha olefin comonomer.

< Example  1>

One) Silane Graft  Modified Ultra Low Density Ethylene Alphaolefin  Preparation of Copolymer

Mw / Mn prepared in Preparation Example 1 was 2.35, and the ultra low density ethylene / 1-octene copolymer having a density of 0.875 g / cc was a twin screw extruder (L / D = 40, diameter 27mm, residence time 1 minute, pressure 23bar The vinyl silane-modified ethylene / 1-octene copolymer was prepared by graft reaction with the vinyltrimethoxysilane monomer injected into the peroxide (trade name Lupersol 101) catalyst mixed phase in. At this time, the introduced silane was 2.0 wt% (0.3 kg / hr), and the peroxide catalyst amount was 1/50 of the silane. The reaction temperature of the extruder was 50 ° C. at which the copolymer and silane were injected, the reaction part proceeding under nitrogen injection was 210 ° C., and the discharge temperature after the reaction was 140 ° C.

2) Encapsulant  Manufacture of sheets

Silane graft modified ultra low density ethylene / 1-octene copolymer, ultra low density ethylene-alpha olefin copolymer prepared in Preparation Example 1, low density ethylene-alpha olefin copolymer prepared in Preparation Example 2 0.2 wt% of stabilizer (trade name Irganox1010), 0.5 wt% of benzotriazole UV absorber (trade name Cyasorb UV-5411) and 0.5 wt% of hindered amine light stabilizer (trade name Cyasorb UV-3853S) were twin screw extruders (L). / D = 40) to produce a 0.4 mm thick sheet. Nitrogen was injected into the extruder and the extruder temperature ranged from 80 to 210 ° C.

3) Manufacturing of solar cell module

The solar cell module was manufactured using the encapsulant sheet having a thickness of 0.4 mm and a vacuum laminator. As a detailed process of manufacturing the solar cell module, the low iron tempered glass, which is the front glass, was disposed at the bottom, and the encapsulant sheet and the crystalline silicon solar cell prepared were disposed. In addition, the fluorine-based back sheet consisting of the prepared encapsulant sheet and Tedlar / PET / Tedlar structure was arranged. The solar cell module was manufactured by heating up to 150 degreeC for 5 minutes, reducing the inside of the arranged module.

4) Characterization

The encapsulant sheet and the solar cell module including the same according to the present invention and the conventional encapsulant sheet, EVA or PVB (polyvinyl butyral) and the solar cell module including the same, were evaluated as follows.

The transparency of the sheet prepared by the above method was calculated using the HR-100 (light source D65) machine.

Transmittance (%) = 100 × (total transmitted light amount) / (incident light amount)

In addition, the adhesive strength of the low iron tempered glass by using the low-strength glass and the adhesive strength (N / m) of the sealing material at a peeling rate of 50 mm / min at a peeling method of 180 ° (ASTM D903) to evaluate the characteristics The results are shown in Table 2 below. In addition, the moisture barrier properties of the encapsulant sheet produced by the above method is 1.2 g / m ² ? As for 24hr, the water blocking effect was 10 times better than the conventional EVA sheet. In addition, as a result of evaluating the adhesion of the encapsulant sheet prepared by the above method to the tempered glass and the backsheet of the solar cell module using a 180 ° peel test (adhesive strength) 37 N / cm In most of the samples, peeling occurred mostly inside the backsheet, rather than peeling at the interface between the sheet prepared by the above method and the glass or backsheet.

In order to evaluate the power of the solar cell module using the ethylene-alpha olefin copolymer, the voltage and current values of the solar cell module were measured by irradiating a 1 kW light source using the Sun Simulator, and the results were within 0.5% of the module using the EVA sheet. Efficiency increase and decrease were observed, indicating that the photovoltaic cell efficiency was equivalent to that of the solar cell module using the EVA sheet. Excellent water barrier properties and good adhesion and transparency properties in modules are properties that EVA, polyvinyl butyral (PVB), or conventional materials used as conventional encapsulant materials cannot simultaneously realize.

< Example  2>

Except that the composition described in Table 2 was used, the encapsulant sheet and the solar cell module were manufactured in the same manner as in Example 1.

< Comparative example  1 to 4>

Except that the composition described in Table 2 was used, the encapsulant sheet and the solar cell module were manufactured in the same manner as in Example 1.

From the above results, the encapsulant sheet according to the present invention is made uniform by using a blend resin of an ultra low density ethylene-alpha olefin copolymer, a low density ethylene-alpha olefin copolymer, and a silane graft modified ultra low density ethylene-alpha olefin copolymer. It can be seen that the alpha olefin comonomer distribution not only has excellent transparency, but also has excellent water barrier property and excellent adhesion with the solar cell module member. In addition, the encapsulant sheet according to the present invention does not require a separate curing process, unlike the conventional EVA sheet, it is excellent in the production speed and production efficiency of the solar cell module.

1 is a cross-sectional view of any one of the solar cell module according to the present invention.

Claims (14)

1) an ethylene-alpha olefin copolymer having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5, a density of 0.85 to 0.89 g / cc, and satisfying the following formula (1), 2) an ethylene-alphaolefin copolymer having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5 and a density of greater than 0.89 g / cc and less than 0.92 g / cc, and 3) A silane graft modified ethylene-alpha olefin copolymer comprising an ethylene-alpha olefin copolymer having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5 and a density of 0.85 to 0.89 g / cc and a silane compound. Encapsulant Sheet with Blend Resin: [Equation 1] Re × Rc ≤ 1.00 In Equation 1, Re and Rc are each a ratio of reactivity of an ethylene monomer (e: ethylene) and a comonomer (c: comonomer), and are defined as Re = kee / kec and Rc = kcc / kce, where kec is The growth reaction rate constant when the comonomer is added to the growth chain where the terminal active point is the ethylene monomer, kee is the growth reaction rate constant when the ethylene monomer is added to the growth chain where the terminal active point is ethylene monomer, kce is the terminal activity The point is the growth reaction rate constant when the ethylene monomer is added to the growth chain of the comonomer, and kcc is the growth reaction rate constant when the comonomer is added to the growth chain of the terminal active point. delete The encapsulant sheet according to claim 1, wherein the melt index (MI) of the 1) ethylene-alpha olefin copolymer is 0.2 to 40 g / 10 min. The encapsulant sheet according to claim 1, wherein the melt index (MI) of the ethylene-alpha olefin copolymer is 0.2 to 40 g / 10 min, and the melting temperature is more than 80 ° C and 120 ° C or less. The method according to claim 1, wherein the alpha olefin of 1) ethylene-alpha olefin copolymer and 2) ethylene-alpha olefin copolymer is propylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene , 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-aitocene, norbornene, norbornadiene, ethylidenenorbornene, To phenylnorbornene, vinylnorbornene, dicyclopentadiene, 1,4-butadiene, 1,5-pentadiene, 1,6-hexadiene, styrene, alpha-methylstyrene, divinylbenzene and 3-chloromethylstyrene Encapsulant sheet comprising at least one member selected from the group consisting of. The sealing material sheet according to claim 1, wherein the silane-based compound of 3) is an ethylenically unsaturated silane compound containing a vinyl functional group. The encapsulant sheet according to claim 1, wherein the content of the silane compound of 3) is 0.05 to 5.0 wt% based on the ethylene-alpha olefin copolymer. The method of claim 1, wherein 1) the content of the ethylene-alpha olefin copolymer is greater than 0 and 85 wt% or less, 2) the content of the ethylene-alpha olefin copolymer is 10 to 90 wt%, and 3) silane graft modification. Encapsulation sheet, characterized in that the content of the ethylene-alpha olefin copolymer is 5 to 90 wt%. The encapsulant sheet according to claim 1, wherein the encapsulant sheet further comprises at least one member selected from the group consisting of an ultraviolet absorber, a light stabilizer, a heat stabilizer, and an antioxidant. The encapsulant sheet according to claim 1, wherein the encapsulant sheet has a thickness of 0.2 to 0.8 mm. The transparency of the encapsulant sheet according to claim 1, wherein the transparency of the encapsulant sheet is 91% or more, and the moisture barrier property is 1.0 to 2.0 g / m ² ? It is a 24hr sealing material sheet. a) an ethylene-alpha olefin copolymer having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5, a density of 0.85 to 0.89 g / cc, and satisfying the following formula 1, 2) a molecular weight distribution (Mw / Mn) Ethylene-alpha olefin copolymer having a density of 1.5 to 3.5 and a density of more than 0.89 g / cc and less than 0.92 g / cc, and 3) a molecular weight distribution (Mw / Mn) of 1.5 to 3.5 and a density of 0.85 to 0.89 g / cc. Preparing a blend resin composition comprising a silane graft modified ethylene-alphaolefin copolymer comprising an ethylene-alphaolefin copolymer and a silane compound, and b) a method of manufacturing an encapsulant sheet comprising forming a sheet using the blend resin composition: [Equation 1] Re × Rc ≤ 1.00 In Equation 1, Re and Rc are each a ratio of reactivity of an ethylene monomer (e: ethylene) and a comonomer (c: comonomer), and are defined as Re = kee / kec and Rc = kcc / kce, where kec is The growth reaction rate constant when the comonomer is added to the growth chain where the terminal active point is the ethylene monomer, kee is the growth reaction rate constant when the ethylene monomer is added to the growth chain where the terminal active point is ethylene monomer, kce is the terminal activity The point is the growth reaction rate constant when the ethylene monomer is added to the growth chain of the comonomer, and kcc is the growth reaction rate constant when the comonomer is added to the growth chain of the terminal active point. The solar cell module comprising the encapsulant sheet of any one of claims 1 and 3 to 11. 1) an ethylene-alpha olefin copolymer having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5, a density of 0.85 to 0.89 g / cc, and satisfying the following formula (1), 2) an ethylene-alphaolefin copolymer having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5 and a density of greater than 0.89 g / cc and less than 0.92 g / cc, and 3) A silane graft modified ethylene-alpha olefin copolymer comprising an ethylene-alpha olefin copolymer having a molecular weight distribution (Mw / Mn) of 1.5 to 3.5 and a density of 0.85 to 0.89 g / cc and a silane compound. Resin composition: [Equation 1] Re × Rc ≤ 1.00 In Equation 1, Re and Rc are each a ratio of reactivity of an ethylene monomer (e: ethylene) and a comonomer (c: comonomer), and are defined as Re = kee / kec and Rc = kcc / kce, where kec is The growth reaction rate constant when the comonomer is added to the growth chain where the terminal active point is the ethylene monomer, kee is the growth reaction rate constant when the ethylene monomer is added to the growth chain where the terminal active point is ethylene monomer, kce is the terminal activity The point is the growth reaction rate constant when the ethylene monomer is added to the growth chain of the comonomer, and kcc is the growth reaction rate constant when the comonomer is added to the growth chain of the terminal active point.

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