KR20130058984A - Resin compositions for encapsulating material of photovoltaic cell - Google Patents

Abstract

PURPOSE: A resin composition for encapsulating material of a photovoltaic cell is provided to have excellent transparency, UV stability, high temperature stability, adhesion, and other physical properties, and to have excellent processability. CONSTITUTION: A resin composition for encapsulating material of a photovoltaic cell comprises an ethylene-vinylacetate copolymer. The ethylene-vinylacetate copolymer has a melt index of 2-10 g/10 minutes. The content of vinylacetate is 15-35 wt%. The molecular weight distribution is 4-6. The weight average molecular weight is 80,000-100,000. The fraction with a weight molecular weight of 10,000 or less is 12-18 wt%. The fraction with a weight molecular weight of 100,000 or more is 22-30 wt%. The encapsulating material of a photovoltaic cell includes the resin composition.

Description

Resin composition for solar cell encapsulation material {RESIN COMPOSITIONS FOR ENCAPSULATING MATERIAL OF PHOTOVOLTAIC CELL}

The present invention relates to a resin composition for solar cell encapsulating material, and more particularly, to a resin composition for solar cell encapsulating material comprising an ethylene-vinylacetate copolymer.

In recent years, the global warming problem is increasing worldwide, and various efforts are continuously made to suppress the emission of carbon dioxide. Increasing consumption of fossil fuels has a significant impact on the global environment, leading to an increase in atmospheric nitrous oxide and the resulting increase in global temperatures due to the greenhouse effect. In order to solve these environmental problems, attention is focused on the development of renewable energy, and in particular, photovoltaic power generation using solar energy is spotlighted as the next generation energy business.

On the other hand, a solar cell used for solar power generation is composed of a photovoltaic cell that directly converts the energy of sunlight into electricity, and generates electricity from a silicon-based semiconductor in the cell. In this case, the cells are not used as they are, and in general, a module is manufactured by wiring several to several tens of cells in series or in parallel. The surface on which solar light enters the module is covered with a glass surface, the gap is filled with a sealing material made of a thermoplastic resin, in particular, an ethylene-vinylacetate copolymer, and a rear sheet is disposed on the rear surface.

Ethylene-vinylacetate copolymer is most frequently used when manufacturing such encapsulant, and when the ethylene-vinylacetate copolymer is used as encapsulant, the solar cell module is protected from moisture when exposed to the external environment, and has excellent advantages in transparency. However, there is a problem that yellowing is easily generated when exposed to ultraviolet rays due to the poor weather resistance to ultraviolet rays. Yellowing is a phenomenon in which the color changes to yellow, which not only lowers the solar absorption efficiency of the solar cell, but also has a problem in that it is poor in adhesiveness when used for a long period of time, thereby deteriorating durability.

In addition, since the solar cell is installed on the exterior wall of a building or an external facility directly receiving sunlight, it is always exposed to the external environment, and therefore, characteristics such as adhesiveness, UV stability, heat stability, and high temperature and high humidity stability are required for long-term use. . In order to overcome these disadvantages, a lot of research is being conducted.

The general solar cell module has a glass-to-sheet type in which glass is used as a front cover and a back sheet is used as a rear cover.

In the case of the conventional ethylene-vinylacetate copolymer resin composition, it is suitable for sheet molding using a T-die extruder, but there is a problem in that the processing load is too low to be used for a high productivity calendar molding machine and thus cannot be applied. In addition, there is a problem in that there is a sticky property, it is difficult to stick to each other in the rolled state in the rolled state, not only to use separate release paper, but also difficult to handle at the time of work, thereby decreasing productivity.

WO2006 / 070793 discloses that an amorphous or low crystalline α-olefin copolymer or composition thereof is applied to a solar cell encapsulation material, thereby improving productivity by eliminating the crosslinking process, but using an ethylene-vinylacetate copolymer. Compared with an encapsulant having a main component, the price is very high, transparency is low, and hardness is high.

Republic of Korea Patent Publication No. 2007-0063800, dispersing the nano-composite in the ethylene-vinylacetate copolymer to increase the stability, but the price is increased, the light transmittance is lowered has a disadvantage of lowering the solar cell efficiency.

Japanese Laid-Open Patent Publication No. 2008-311537 laminates an intermediate layer composed mainly of an ethylene-vinylacetate copolymer and an outer layer composed mainly of an ethylene methacrylic acid ester copolymer on both surfaces thereof, thereby improving the stability of adhesion, but producing a set. The method is difficult, and since the different materials are layered, the light transmittance is lowered, which lowers the solar cell efficiency.

Korean Patent Laid-Open Publication No. 2009-0112315 improves the UV blocking rate and durability by stacking three sheet layers having different melt indexes and vinyl acetate contents, but has a problem of resin flow when manufacturing a module with low melt viscosity.

Accordingly, the present invention has been made to solve the above problems, while having excellent physical properties such as transparency, UV stability, heat stability, high temperature and high humidity stability, adhesiveness, by controlling the molecular weight characteristics, in particular, has a workability suitable for calendar molding machine, To provide a resin composition for a solar cell encapsulant comprising an ethylene-vinylacetate copolymer having optimal properties for manufacturing a solar cell encapsulation material that is not sticky, does not require release, and is easy to handle, thus reducing productivity problems. do.

In addition, the present invention is to provide a solar cell encapsulation material comprising the composition and a solar cell module manufactured using the same.

In order to solve the above problems, the present invention provides a resin composition for a solar cell module encapsulant comprising an ethylene-vinylacetate copolymer, wherein the ethylene-vinylacetate copolymer has a melt index of 2 to 10 g / 10 minutes and a vinyl acetate content 15 to 35% by weight, molecular weight distribution (MWD) of 4 to 6, weight average molecular weight (Mw) of 80,000 to 100,000, weight molecular weight of 10,000 or less, 12 to 18% by weight, and weight molecular weight of 100,000 or more of 22 to 30 weight It provides the resin composition for solar cell sealing materials which is%.

The present invention for solving the another problem, provides a solar cell sealing material comprising the resin composition for solar cell sealing material.

Solving the above another problem, the present invention provides a solar cell module manufactured using the solar cell encapsulant.

According to the present invention, it has excellent physical properties such as adhesiveness, transparency, crosslinking degree, UV stability, heat stability, high temperature and high humidity stability, and exhibits excellent processability essential for calender molding machine due to sufficiently high weight average molecular weight and high molecular weight of 100,000 or more molecular weight. Since there is little stickiness, no release paper is needed, and the resin composition for a calendered solar cell encapsulation material that can be easily handled and solves a problem of lowering productivity can be obtained.

In addition, it is possible to provide a solar cell module encapsulant including the resin composition for solar cell encapsulant and a solar cell module manufactured using the same.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims and their equivalents. It is to be understood that various equivalents and modifications may be substituted for those at the time of the present application.

MEANS TO SOLVE THE PROBLEM The present inventors earnestly researched in order to solve the problem which arises when using the conventional ethylene-vinylacetate copolymer resin composition for a calender molding machine, As a result, ethylene-vinylacetate which has a specific melt index, content, molecular weight distribution, and a weight molecular weight fraction When the copolymer is included, it has excellent physical properties such as adhesiveness, transparency, UV stability, thermal stability, and high temperature and high humidity stability, but the weight average molecular weight and the weight molecular weight of 100,000 or more are surprisingly high, so that the workability is particularly suitable for calender molding machine. The present invention has been found to be capable of producing a resin composition for a solar cell encapsulant that has a non-sticky property, does not require release, and is easy to handle, thus solving a problem of lowering productivity.

Therefore, according to one aspect of the invention, the resin composition for solar cell module encapsulation material comprising an ethylene-vinylacetate copolymer, the ethylene-vinylacetate copolymer, the melt index is 2 ~ 10g / 10 minutes, vinyl acetate content The fraction of 15 to 35% by weight, the molecular weight distribution (MWD) of 4 to 6, the weight average molecular weight (Mw) of 80,000 to 100,000, the weight molecular weight of 10,000 or less is 12 to 18% by weight, and the weight of the molecular weight of 100,000 or more is 22 to 30 Disclosed is a resin composition for a solar cell encapsulant that is% by weight.

The ethylene-vinylacetate copolymer used in the resin composition for solar cell encapsulation according to the present invention is a polymer produced by a copolymerization reaction of ethylene and vinyl acetate (VA). In general, as the content of vinyl acetate increases, the elastic modulus and thermal bonding temperature of the film decrease, while the impact strength, tear strength and permeability increase. The content of such vinyl acetate is 15% by weight or more based on the total weight of ethylene-vinylacetate is mainly used as the base resin of the adhesive or waxes. In addition, ethylene-vinylacetate containing about 18% by weight of vinyl acetate is most often used for flexible packaging. The film is flexible even at low temperature, and the film has low temperature adhesiveness and hot tack. Adhesive strength). In the present invention, the content of such vinyl acetate is 15 to 35% by weight based on the total weight of ethylene-vinylacetate, preferably 24 to 30% by weight. When the vinyl acetate content is less than 15% by weight, transparency may be lowered, and thus the efficiency of the solar cell may be lowered. When the vinyl acetate content is higher than 35% by weight, the melting point of the resin is lowered, and the permeability of the gas is improved, making it difficult to protect the solar cell. Stickiness may be so severe that handling may not be easy.

The molecular weight distribution of the ethylene-vinylacetate copolymer used in the resin composition for solar cell encapsulation according to the present invention is 4 to 6, and the molecular weight distribution (MWD) is a property of synthetic polymers. Is a combination of molecules of various sizes, resulting in a molecular weight distribution. Polymers have different physical properties depending on their molecular weights, and physical properties, rheological properties, and mechanical properties vary depending on their molecular weight distribution. Therefore, the molecular weight of the synthetic polymer is expressed as weight average molecular weight (Mw). At this time, the weight average molecular weight of ethylene-vinylacetate used in the present invention is characterized in that 80,000 ~ 100,000. When the weight average molecular weight is less than 80,000, the melt viscosity of the encapsulating material may be too low, and when the weight average molecular weight exceeds 100,000, workability may decrease.

In addition, the ethylene-vinylacetate copolymer used in the resin composition for solar cell module encapsulation according to the present invention has a weight molecular weight of 10,000 or less, 12 to 18% by weight, and a weight molecular weight of 100,000 or more, 22 to 30% by weight. It is characterized by. When the weight molecular weight of 10,000 or less is less than 12% by weight, the adhesion may be sharply reduced, and when it exceeds 18% by weight, the heat resistance and the degree of crosslinking may be reduced. In addition, when the weight molecular weight of 100,000 or less is less than 22% by weight, it is difficult to maintain a weight average molecular weight of 80,000 to 100,000, so that the workability and productivity in the calendering machine may be drastically lowered. And productivity may be drastically reduced.

Melt index of the ethylene-vinylacetate copolymer used in the resin composition for solar cell encapsulation according to the present invention is characterized in that 2 ~ 10g / 10 minutes. When the melt index is less than 2g / 10 minutes, the workability may be excessively lowered due to excessive load increase in the calender molding machine, and when the melt index exceeds 10g / 10 minutes, the viscosity of the molten resin is too low to be used in the calender molding machine so that the calender roll It may not be suitable for use as a resin for encapsulating calendered solar cells because the sheet may not be processed due to being stuck or broken.

On the other hand, the ethylene-vinylacetate copolymer used in the resin composition for solar cell encapsulation according to the present invention is preferably polyethylene produced in a high pressure autoclave reactor. The copolymer may be prepared in a high-pressure tubular (tubular) reactor in addition to the reactor, there is a limit to increase the content of vinyl acetate, it is not suitable for use in solar cell encapsulation material that requires high transparency.

According to another aspect of the present invention, the present invention discloses a solar cell encapsulation material comprising the resin composition for solar cell encapsulation material.

Since the solar cell encapsulant uses ethylene-vinylacetate, it has high adhesiveness, transparency, UV stability, thermal stability and high temperature and high humidity stability, as well as workability suitable for calender processing equipment due to its high weight average molecular weight and is not sticky. It is easy to handle.

Hereinafter, a method for manufacturing a solar cell encapsulation material according to the present invention will be described in detail.

Solar cell encapsulation material according to the present invention, for example, a) 65 to 85% by weight of ethylene and 15 to 35% by weight of vinyl acetate copolymerization reaction in a high pressure autoclave reactor, melt index of 2 to 10g / 10 minutes, 15 Preparing an ethylene-vinylacetate copolymer having a vinyl acetate content of ˜35 wt%, a molecular weight distribution of 4 to 6 and a weight average molecular weight of 80,000 to 100,000; b) mixing 0.5 to 2 parts by weight of crosslinking agent, 0.01 to 0.05 part by weight of antioxidant and 0.05 to 0.15 part by weight of anti-sticking agent to 100 parts by weight of the ethylene-vinylacetate copolymer; And c) crosslinking the mixture at 120 to 180 ° C. using a molding machine to prepare an encapsulant. In this case, in order to apply the resin composition for solar cell encapsulation material of the present invention to various solar cell encapsulation materials, a general polyethylene additive may be added to the ethylene-vinylacetate copolymer of the present invention. For example, antioxidants, heat and light stabilizers, crosslinking agents, antistatic agents, lubricants, antiblocking agents, preservatives, processing aids, slip agents, pigments, flame retardants, foaming agents and the like can be added.

According to another aspect of the present invention, the present invention discloses a solar cell module manufactured using the solar cell module encapsulant.

The solar cell module according to the present invention may include a front cover, a rear cover, a solar cell, an encapsulant, and a connection terminal. In this case, a colorant, an antioxidant, a discoloration inhibitor, and the like may be further used, and the encapsulant is preferably located between the front cover and the battery and between the rear cover and the battery. The solar cell module may be manufactured by a general method known in the art, and the solar cell used may be any type of solar cell including amorphous silicon type, crystalline silicon type, compound type, dye-absorbing type, organic material type, and the like. Although a battery is possible, it is preferable to use a crystalline silicon solar cell.

The ethylene-vinylacetate copolymer used for the resin composition for solar cell sealing materials which concerns on this invention is excellent in workability, but has high adhesiveness. On the other hand, if the copolymer is applied to the solar cell encapsulant, since the melting point of the ethylene-vinylacetate copolymer is 55 ~ 80 ℃ may be a problem of melting when absorbing high temperature solar heat. In order to solve this problem, the encapsulant is crosslinked. In this case, when a copolymer having high adhesiveness is used, even if the degree of crosslinking is lower than that of other encapsulants, it can be fixed. Therefore, since the solar cell module encapsulant according to the present invention uses an ethylene-vinylacetate copolymer having excellent adhesiveness, it is possible to reduce the amount of crosslinking agent added during the manufacture of the encapsulant, thereby reducing the cost. In addition, since the crosslinking time can be saved by lowering the crosslinking temperature of the ethylene-vinylacetate copolymer during solar cell module manufacturing, energy saving and productivity improvement effects can be expected. In addition, the adhesive strength is excellent because the adhesive strength can be maintained even if the solar cell encapsulant is manufactured thinly, and thus the efficiency of the solar cell can be increased.

Hereinafter, examples and comparative examples of the present invention will be described in more detail.

Example  One

First, an ethylene-vinylacetate copolymer to be used in the resin composition for encapsulating solar cells according to the present invention was prepared as follows. That is, after setting the pressure of the autoclave reactor at 1,550 kg / cm3, the upper temperature at 230 占 폚 and the lower temperature at 270 占 폚, ethylene gas and vinyl acetate monomer compressed at a high pressure of 1,600 kg / And then the mixture was polymerized. After the polymerization initiator was diluted with hydrocarbon, t-butyl-peroxybenzoate was added to the upper part of the reactor using a hydraulic driving pruning pump, and di-t-butyl peroxide was added to the lower part . At this time, the stirring was carried out at a stirring speed of 920 rpm in the reactor. After the reaction, the polymerized ethylene-vinyl acetate polymer was extruded by a 18-inch single screw extruder at a rate of 14 ton / h to prepare a pellet shape. Melting index 4g / 10 minutes, vinyl acetate content 26% by weight, weight average molecular weight 95,000, 14.6 weight% or less by weight molecular weight 10,000 or less and weight molecular weight 100,000 or more by adjusting temperature and pressure, residence time in the reactor, etc. An ethylene-vinylacetate copolymer of 28.2% by weight was prepared.

Thereafter, 1 part by weight of dicumyl peroxide as a crosslinking agent and 100 parts by weight of the ethylene-vinylacetate copolymer, and octadecyl-3- (3,5-di-tert-butylbutyl-hydroxyphenyl) propionate as an antioxidant. 0.02 parts by weight and 0.09 parts by weight of oleyl palmitamide as an anti-sticking agent were mixed at 800 rpm in a Henschel mixer at room temperature for 10 minutes, and then crosslinked at 150 ° C. for 5 minutes using a press molding machine to prepare a 0.5 mm thick encapsulant. .

Example  2

In Example 1, the ethylene-vinylacetate copolymer had a melting index of 4.3g / 10min, a vinylacetate content of 27% by weight, a weight average molecular weight of 92,000, a weight molecular weight of 10,000 or less, 14.4% by weight, and a weight molecular weight of 100,000 or more of 25.4% by weight. Except for the ethylene-vinylacetate copolymer and the sealing material was prepared in the same manner as in Example 1.

Example 3

In Example 1, the ethylene-vinylacetate copolymer has a melt index of 4.5 g / 10 minutes, a vinyl acetate content of 28% by weight, a weight average molecular weight of 86,000, a weight molecular weight of 10,000 or less, 14.0% by weight, and a weight molecular weight of 100,000 or more of 22.5% by weight. Except for the ethylene-vinylacetate copolymer and the sealing material was prepared in the same manner as in Example 1.

Comparative example  One

In Example 1, except that the ethylene-vinylacetate copolymer is 14g / 10 minutes of melt index, 28% by weight vinyl acetate content, 69,000 weight average molecular weight and 16.8% by weight fraction of 100,000 or more weight molecular weight. An ethylene-vinylacetate copolymer and an encapsulant were prepared by the method.

Comparative example  2

In Example 1, the ethylene-vinylacetate copolymer has a melt index of 18 g / 10 minutes, a vinyl acetate content of 28% by weight, a weight average molecular weight of 65,000, a weight molecular weight of 10,000 or less, 17.2% by weight, and a weight molecular weight of 100,000 or more of 17.3% by weight. Except that was prepared in the same manner as in Example 1 ethylene-vinylacetate copolymer and encapsulant.

Comparative example  3

In Example 1, the ethylene-vinylacetate copolymer has a melt index of 16 g / 10 minutes, a vinyl acetate content of 28% by weight, a weight average molecular weight of 70,000, a weight molecular weight of 10,000 or less, 13.9% by weight, and a weight molecular weight of 100,000 or more of 19.5% by weight. Except that was prepared in the same manner as in Example 1 ethylene-vinylacetate copolymer and encapsulant.

Comparative example  4

Except that the ethylene-vinylacetate copolymer in Example 1, the melt index 3.2g / 10 minutes, weight average molecular weight 98,000, weight molecular weight 10,000 or less fraction 11.3% by weight and weight molecular weight 100,000 or more fraction 30.7% by weight An ethylene-vinylacetate copolymer and an encapsulant were prepared in the same manner as in Example 1.

Comparative example  5

In Example 1, the ethylene-vinylacetate copolymer has a melt index of 40 g / 10 minutes, a vinyl acetate content of 32% by weight, a weight average molecular weight of 68,000, a weight molecular weight of 10,000 or less, 20.1% by weight, and a weight molecular weight of 100,000 or more of 20.9% by weight. Except that was prepared in the same manner as in Example 1 ethylene-vinylacetate copolymer and encapsulant.

The ethylene-vinyl acetate copolymer properties according to the above Examples and Comparative Examples are shown in Table 1 below.

division Melt Index
(g / 10 min) Vinyl acetate
content
(weight%) Weight average
Molecular Weight
(Mw) Molecular weight
10,000 or less
Fraction (% by weight) Molecular weight
More than 100,000
Fraction (% by weight) Example 1 4.0 26 95,000 14.6 28.2 Example 2 4.3 27 92,000 14.4 25.4 Example 3 4.5 28 86,000 14.0 22.5 Comparative Example 1 14 28 69,000 14.6 16.8 Comparative Example 2 18 28 65,000 17.2 17.3 Comparative Example 3 16 28 70,000 13.9 19.5 Comparative Example 4 3.2 26 98,000 11.3 30.7 Comparative Example 5 40 32 68,000 20.1 20.9

Experimental Example

The physical properties of the ethylene-vinylacetate copolymer and the sealing material according to the Examples and Comparative Examples were measured according to the following method.

1) Melt index: The MFR (melt flow rate) was measured at a temperature of 125 ° C under a load of 2.16 kg using a measuring machine according to ASTM D1238, and converted to log MI = 0.9394 + 0.9174 log MFR.

2) Vinyl Acetate Content: The content was determined by measuring the area of 1980-2090 cm ^{-1 which} is the reference peak (Peak) and the area ratio of 580-670 cm ^-1 of the vinyl acetate peak, as measured by a Nicolet FT-IR instrument.

3) Molecular weight distribution (MWD): Measured by GPC-FTIR from Polymer Laborotories. The measurement conditions are K value = 14.1, Alpha = 0.725, Set Flow Rate = 1.00 ml / min, speed =. 1.2659 cm / s.

4) Adhesion: Measured by ASTM D903 method.

5) Light transmittance: Measured by ASTM E424 method using a UV-vis spectrophotometer (SHIMADZU, Japan).

6) UV stability: measured at ASTM G154 at 0.89 W at 60 DEG C for 1000 hours.

7) Thermal stability: After 3000 hours in a natural circulation dryer at 90 ℃ by KS M 3026 method, yellowing was observed.

8) High temperature and high humidity stability: After leaving for 3000 hours at 85 ° C. and 85% humidity by KS M 3026 method, yellowing phenomenon was observed.

9) Crosslinking degree measurement: It measured by ASTM D2765 method.

10) Calender processability evaluation: The calender processability was evaluated at 90 degreeC using the calender molding machine.

The results of the physical property evaluation according to the above measurement method are shown in Table 2 below.

division Adhesiveness
(N / cm2) Light transmittance
(%) Degree of crosslinking
(%) UV stability
(Δ YI) Heat stability
(Δ YI) High temperature and high humidity stability
(Δ YI) Calendar
Processability Example 1 28.7 91 90.2 1.1 1.3 2.0 Good Example 2 29.5 91 89.5 1.4 1.5 2.1 Good Example 3 28.4 91 88.1 1.2 1.4 2.0 Good Comparative Example 1 28.6 92 88.4 1.2 1.5 2.1 Bad Comparative Example 2 26.7 91 85.5 1.5 1.7 2.3 Bad Comparative Example 3 28.5 92 91.2 1.1 1.4 2.0 Bad Comparative Example 4 27.3 91 90.3 1.3 1.6 2.2 Bad Comparative Example 5 25.6 87 84.2 1.9 2.3 2.8 Bad

As shown in Table 2, the resin composition for solar cell encapsulation material according to Examples 1 to 3 is excellent in adhesiveness, cloudiness, crosslinking degree, UV stability, heat stability, high temperature and high humidity stability, and the molecular weight of 100,000 or more molecular weight This sufficiently high imparting an appropriate processing load essential to the calender molding machine exhibits excellent workability, while also making the sticky property small, requiring no release and easy handling.

On the other hand, the resin composition for solar cell encapsulation materials according to Comparative Examples 1 to 3 using a copolymer having a melt index of more than 10 g / 10 minutes and a weight average molecular weight of less than 80,000 and a molecular weight of 100,000 or more of a polymer having a molecular weight of less than 22% by weight is resin. As fluidity and stickiness increase, the machinability of the calendar forming machine begins to decrease rapidly. In addition, the resin composition for solar cell encapsulation materials according to Comparative Example 4 using a copolymer having a molecular weight of 10,000 or less in a fraction of less than 12% by weight and a molecular weight of 100,000 or more in excess of 30% by weight has a too high processing load and thus lowers productivity. And the adhesive force is also lowered. In addition, the resin composition for solar cell encapsulation material according to Comparative Example 5 using a copolymer having a molecular weight of 10,000 or less in excess of 18% by weight has a low light transmittance, and is inferior in UV stability, thermal stability, and high temperature and high humidity stability. It turns out that it is not suitable as a resin composition for solar cell sealing materials.

As described above, when the resin composition for solar cell encapsulation material is prepared using the ethylene-vinylacetate copolymer according to the present invention, physical properties such as adhesion, transparency, crosslinking degree, UV stability, heat stability, high temperature and high humidity stability, etc. It is excellent and has high weight average molecular weight and high molecular weight of 100,000 or more, so it shows excellent processability essential for calender molding machine, and it is not sticky and does not require release paper. The resin composition for sealing can be obtained. Therefore, using the resin composition for solar cell sealing materials containing the ethylene-vinylacetate copolymer which concerns on this invention as a solar cell sealing material and the solar cell module manufactured using the said sealing material is also anticipated.

Claims (3)

A resin composition for solar cell module encapsulant comprising an ethylene-vinylacetate copolymer,
The ethylene-vinylacetate copolymer has a melt index of 2 to 10 g / 10 minutes, a vinyl acetate content of 15 to 35% by weight, a molecular weight distribution (MWD) of 4 to 6, a weight average molecular weight (Mw) of 80,000 to 100,000, The resin composition for solar cell sealing materials whose fraction of a molecular weight 10,000 or less is 12-18 weight%, and the fraction of weight molecular weight 100,000 or more are 22-30 weight%. The solar cell sealing material containing the resin composition for solar cell sealing materials of Claim 1. A solar cell module manufactured using the solar cell encapsulant of claim 2.