KR101222216B1 - Method for Manufacturing Excellent Weather Stable EVA sheet for Solar Cell Encapsulant - Google Patents

Abstract

The present invention relates to a method for manufacturing an EVA sheet for solar cell encapsulation material, characterized in that the sheet is formed by melting and kneading the nanoparticles and the light stabilizer in a EVA resin, a crosslinking agent, a crosslinking aid and a silane coupling agent at a decomposition temperature below the crosslinking agent. It is about.

Description

Method for manufacturing EAB sheet for solar cell encapsulation with improved weatherability {Method for Manufacturing Excellent Weather Stable EVA sheet for Solar Cell Encapsulant}

The present invention relates to a method for producing an EVA sheet for solar cell encapsulation with improved weather stability, and more particularly, to nanoparticles, light stabilizers, crosslinking agents, crosslinking aids in ethylene vinyl acetate copolymer (hereinafter referred to as EVA) resin. And it relates to a method for producing a EVA sheet for solar cell encapsulation material characterized in that the sheet is formed by mixing a silane coupling agent.

The solar cell module used for solar power generation is usually EVA sheet is used on both sides to protect the cell, and additionally it is laminated with transparent glass substrate on the side where solar light is incident, and sheet on the other side which is excellent in moisture barrier and weather resistance. have. The laminating method is to laminate a transparent glass substrate, an EVA sheet, a cell, an EVA sheet, a gas barrier sheet, and then heat and crosslink the adhesive under a specific temperature and pressure.

Generally, since EVA sheet for solar cell encapsulation material requires high transparency, adhesiveness, and weather resistance after crosslinking, various additives such as a crosslinking agent, a crosslinking aid, a silane coupling agent, an antioxidant, a light stabilizer, and a UV absorber are added to EVA. The EVA sheet for sealing material is manufactured by melt-kneading at the temperature more than the melting temperature of EVA and below the decomposition temperature of the organic peroxide which is a crosslinking agent.

However, EVA sheets used for most solar cell encapsulation materials currently use organic UV absorbers such as benzophenone or benzotriazole, which act as UV absorbers and at the same time react with organic peroxides during sheet production or There was a problem of causing yellowing by reacting with the residual organic peroxide after lamination and curing.

An object of the present invention is to provide a method for producing an EVA sheet for solar cell encapsulation material having good appearance, yellowing stability and weathering stability.

The manufacturing method of the EVA sheet for solar cell sealing material which concerns on this invention is characterized by shape | molding a sheet by mixing a nanoparticle, a light stabilizer, a crosslinking agent, a crosslinking adjuvant, and a silane coupling agent to EVA resin.

The EVA resin used in the present invention preferably has a vinyl acetate (VA) content of 25 to 32% by weight and a melt index (measured at 190 ° C. and a load of 2.16 kg) of 6 to 30 g / 10 minutes. When the content is out of the above range, transparency, flexibility, and blocking resistance are not preferable, and when the melt index is outside the above range, sheet formability and mechanical properties are not preferable, which is not preferable.

The nanoparticles used in the present invention are not particularly limited in kind, and for example, layered clay minerals such as inorganic silicates or layered clay minerals obtained by organizing such layered clay minerals with organic onium ions can be used in a nano size. Can be. Representative examples of the layered clay mineral used in the present invention include smectite-based layered clay minerals such as montmorillonite, hectorite, and saponite, vermiculite, heroisite and the like. In addition, nano-sized titanium dioxide may be used. In this case, coating may be performed with aluminate or silicate to inactivate the surface, or may be coated with an organic agent for uniform dispersion. On the other hand, nano-size zinc oxide can also be used.

It is preferable that the said nanoparticle uses 0.05-1.0 weight part with respect to 100 weight part of EVA resin. When the content of the nanoparticles is less than 0.05 parts by weight, the UV absorption effect is insignificant and not preferable. When the content of the nanoparticles is more than 1.0 parts by weight, transparency is poor or economical is not preferable.

The light stabilizer used in the present invention is not particularly limited in kind, and for example, a hindered amine light stabilizer may be used, and specific examples thereof include bis (2,2,6,6-tetramethyl- 4-piperidyl) sebacate (bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate), bis- (ene-octyloxy-tetramethyl) piperidinyl sebacate (bis- (N- octyloxy-tetramethyl) piperidinyl sebacate), bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate (bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate) and methyl-1,2,2,6,6-pentamethyl-4-piperidyl sebacate (methyl-1,2,2,6,6-pentamethyl-4-piperidyl sebacate) and the like. One or more kinds selected may be used.

The light stabilizer is preferably 0.01 to 0.3 parts by weight based on 100 parts by weight of the EVA resin, but when the content of the light stabilizer is less than 0.01 parts by weight, the light stabilizer effect is insignificant. It is unfavorable because of poor economics.

Examples of the crosslinking agent used in the present invention include organic peroxides. For example, a dialkyl peroxide crosslinking agent having a half-life temperature (decomposition temperature) of 130 to 160 ° C and an alkyl having a half-life temperature of 100 to 135 ° C. 1 or more types chosen from the group which consists of a peroxy ester-type crosslinking agent or a peroxy ketal can be used, and also it can also use together 2 or more types from which the half-life temperature differs for 1 hour.

Specific examples of the dialkyl peroxide crosslinking agent are 2,4-dimethyl-2,5-bis (t-butylperoxy) hexane (2,5-dimethyl-2,5-bis (t-butylperoxy) hexane) Specific examples of the alkyl peroxy ester-based crosslinking agent include t-butyl-2-ethylhexyl monoperoxycarbonate, and the like, and the peroxy ketal system is 1,1-. Di- (t-butylperoxy) -3,3,5-trimethylcyclohexane (1,1-di- (t-butylperoxy) -3,3,5-trimethylcyclohexane) etc. are mentioned.

It is preferable that the said crosslinking agent contains 0.3-1.5 weight part with respect to 100 weight part of EVA resin, but when it is less than 0.3 weight part, the crosslinking effect is insignificant, and it is unpreferable, and when it exceeds 1.5 weight part, it is unpreferable in economical efficiency.

The type of crosslinking aid used in the present invention is not particularly limited, and for example, a polyallyl compound or a polymethacryloxy compound can be used, and specific examples thereof include triallyl isocyanurate and the like. Can be mentioned.

It is preferable that the said crosslinking adjuvant contains 0.3-1.5 weight part with respect to 100 weight part of EVA resin, but when it is less than 0.3 weight part, the crosslinking effect is insignificant, and when it exceeds 1.5 weight part, it is unpreferable in economical efficiency.

The silane coupling agent used in the present invention is not particularly limited in kind, and for example, an organosilicon compound can be used, and specific examples thereof include 3-methacryloxypropyl methoxy silane (3-Methacryloxypropyl trimethoxysilane) and the like. Can be mentioned.

The silane coupling agent preferably contains 0.3 to 1.5 parts by weight with respect to 100 parts by weight of EVA resin, but less than 0.3 parts by weight is not preferred because it does not exhibit an additive effect. not.

In the method for manufacturing a sheet for solar cell encapsulant according to the present invention, in addition to the above components, conventional additives may be further added as necessary.

In one embodiment, the manufacturing method of the EVA sheet for solar cell encapsulation material of the present invention, by mixing the nanoparticles, light stabilizer, crosslinking agent, crosslinking aid and silane coupling agent together with the EVA resin by melt kneading at the decomposition temperature of the crosslinking agent below Molding the sheet.

In another embodiment, the method for producing an EVA sheet for solar cell encapsulation of the present invention comprises the following steps:

(1) melting and kneading nanoparticles (nanoparticle) and light stabilizer at 80 ~ 220 ℃ to EVA resin to obtain a resin composition, and

(2) mixing the crosslinking agent, the crosslinking aid and the silane coupling agent to the EVA resin composition obtained in the step (1) to melt kneading at a temperature below the decomposition temperature of the crosslinking agent to form a sheet.

In the step (1), the temperature at the time of melt kneading is preferably 80 ~ 220 ℃, if out of this temperature range, sheet formability is bad, it is not preferable.

In the step (2), the crosslinking agent, the crosslinking aid and the silane coupling agent are mixed with the EVA resin composition obtained in the step (1) to melt kneading at a temperature below the decomposition temperature of the crosslinking agent to form a sheet.

Alternatively, in step (2), the crosslinking agent, crosslinking aid, and silane coupling agent may be dissolved in an extruder under the decomposition temperature of the organic peroxide, in which the EVA resin composition obtained in the above step (1) is uniformly dispersed in the EVA resin composition. The mixture may be supplied to the extruder through a separate raw material supply device and melt kneaded to form a sheet.

In the step (2), when melt kneading at a temperature higher than the decomposition temperature of the crosslinking agent, sheet formability is bad or cross-linking occurs, which is not preferable.

According to the present invention, by adding nanoparticles instead of the conventional organic UV absorber, not only the appearance and yellowing stability but also the weathering stability are improved, and the photoelectric effect is improved by partially releasing the cut off of the UV region. You can also plan.

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

Example # 1

According to the composition of Table 1, with respect to 100 parts by weight of EVA resin (28% by weight of vinyl acetate, melt index of 15 g / 10 minutes, Samsung Total E280PV) containing no additives, Cloisite 15A ((Dimethyl) 0.25 parts by weight of montmorillonite modified with hydrogenated tallow 2-ethylhexyl ammonium and BASF's Tinuvin 770 (bis (2,2,6,6-tetramethyl-4-piperidyl) ceva as UV stabilizer (light stabilizer) Kate) # 0.1 weight part was mixed, it put in the extruder, melt-kneading at extrusion temperature 190 degreeC, and the pellet-form EVA resin composition was obtained.

0.7 parts by weight of Luperox TBEC (t-butyl-2-ethylhexyl monoperoxycarbonate) manufactured by Alchema Co., Ltd. as a crosslinking agent with respect to 100 parts by weight of the EVA resin composition pellet obtained above, TAICROS (triallyl isocyanur) manufactured by Evonik Co., Ltd. Rate) 0.5 parts by weight and 0.5 parts by weight of OFS 6030 (3-methacryloxypropyltrimethoxysiloxane) manufactured by Dow Corning Co., Ltd. with a silane coupling agent, and the extruder temperature was set to 90 ° C and the T-die temperature was set to 100 ° C The sheet having a thickness of 0.45 mm was prepared with a linear velocity of 6.5 meters per minute.

Example 2

Sheets were prepared in the same manner as in Example 1, except that 0.25 parts by weight of Solasorb UV 100 of Croda, a nano-sized titanium dioxide, was added as nanoparticles.

Example 3

Sheets were prepared in the same manner as in Example 1, except that 0.25 parts by weight of Solasorb UV 200 of Croda, a nano-sized zinc oxide, was added as nanoparticles.

Comparative Example 1

Vasp's Chimassorb 81 (2-hydroxy-4-octyloxy-) as a UV absorber based on 100 parts by weight of EVA resin (28% by weight of vinyl acetate, 15 g / 10 min of melt index, Samsung Total E280PV) according to the composition of Table 1. Benzophenone) 0.3 parts by weight, BASF Tinuvin 770 (bis (2,2,6,6, -tetramethyl-4-piperidyl) sebacate) 0.1 parts by weight, UV stabilizer, Alkema Luperox TBEC (t 0.7 parts by weight of -butyl-2-ethylhexyl monoperoxycarbonate), 0.5 parts by weight of TAICROS (triallyl isocyanurate) from Evonik as a crosslinking aid, and OFS 6030 (3-methacryl) from Dow Corning as a silane coupling agent. Oxypropyltrimethoxysiloxane) 0.5 parts by weight was mixed, and a sheet having a thickness of 0.45 mm was produced with an extruder temperature of 90 ° C and a T-die temperature of 100 ° C and a linear speed of the sheet of 6.5 meters per minute.

Comparative Example 2

Comparative example 1 except that 0.3 part by weight of Tinuvin 326 (2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole) manufactured by BASF Corporation was added as a UV absorber. In the same manner as in the sheet was prepared.

Table 1 shows the external appearance of the sheets obtained in Examples 1-3 and Comparative Examples 1-2.

(Unit: parts by weight) Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 EVA resin EVA E280PV 100 100 100 100 100 Nanoparticles Cloisite 15A 0.25 - - - - Solasorb UV 100 - 0.25 - - - Solasorb UV 200 - - 0.25 - - UV stabilizer Tinuvin 770 0.1 0.1 0.1 0.1 0.1 UV absorbers Chimassorb 81 - - - 0.3 - Tinuvin 326 - - - - 0.3 Cross-linking agent Luperox TBEC 0.7 0.7 0.7 0.7 0.7 Crosslinking auxiliary Taicros 0.5 0.5 0.5 0.5 0.5 Silane coupling agent OFS 6030 0.5 0.5 0.5 0.5 0.5 Sheet exterior transparent transparent transparent light
Yellow and transparent light
Yellow and transparent

Example 4

Place one sheet of EVA sheet (200 mm x 160 mm) obtained in Example 1 on the low iron tempered glass (200 mm x 200 mm), and place the DNP backsheet (200 mm x 200 mm) on it, and vacuum step for 6 minutes at a temperature of 150 ° C. Then, the specimen was prepared by cross-linking by maintaining the difference between the laminator upper pressure and the lower pressure at 100 Mpa for 16 minutes. After observing the internal bubbles and residual conditions of the prepared specimens after the cooling process at room temperature, the crosslinking degree was measured for the crosslinked specimens, and the tensile strength and elongation and colorimeter (Hunter Lab., UltraScan) with Hunter Lab's Ultrascan Prospect. After measuring yellowness (YI) with PRO Colorimeter, and after 1,000 hours in UV irradiation (340nm, 60 ℃) and constant temperature and humidity (85 ℃, 85% relative humidity) for weather stability test, tensile strength difference, elongation The difference and yellowness difference (ΔYI) were evaluated.

Example 5

Except for using the sheet prepared in Example 2, the specimen was prepared in the same manner as in Example 4, and observed, measured and evaluated in the same manner.

Example 6

Except for using the sheet prepared in Example 3, the specimen was prepared in the same manner as in Example 4, observed, measured and evaluated in the same manner.

Comparative Example 4

Except for using the sheet prepared in Comparative Example 1, a specimen was prepared in the same manner as in Example 4, observed, measured and evaluated in the same manner.

Comparative Example 5

Except for using the sheet prepared in Comparative Example 2, a specimen was prepared in the same manner as in Example 4, observed, measured and evaluated in the same manner.

Table 2 shows the results of evaluating the physical properties of the crosslinked sheets obtained in Examples 4-6 and Comparative Examples 4-5.

Example 4 Example 5 Example 6 Comparative Example 4 Comparative Example 5 Weather stability test period (hr) 0 1000 0 1000 0 1000 0 1000 0 1000 Degree of crosslinking (%) 88.5 90.7 89.5 90.2 90.0 Light transmittance (%) 90.5 87 88 91 90.5 Tensile Strength (DH)
(kgf / cm2) 240 197 277 248 248 182 247 215 177 212 Tensile strength (UV)
(kgf / cm2) 202 178 163 105 187 Elongation (DH) (%) 550 490 577 509 563 513 536 530 569 538 Elongation (UV) (%) 520 504 501 468 537 YI (DH) 1.69 5.9 1.63 4.4 1.55 5.9 1.73 6.1 8.88 10.6 YI (UV) 8.05 4.75 7.65 8.34 18.98

* UV = UV irradiation (340nm, 60 ℃)

* DH = constant temperature and humidity (85 ℃, relative humidity 85%)

As shown in the results of Table 1 and Table 2, in the case of the method according to the present invention, it is possible to manufacture a transparent solar cell encapsulation EVA sheet and when laminating and crosslinking with the sheet produced by the method of the present invention As well as good appearance and yellowing stability, it can be seen that the weathering stability is further improved.

Claims (10)

Method for producing an ethylene vinyl acetate copolymer sheet for a solar cell encapsulation material comprising the following steps:
(1) melting and kneading nanoparticles and a light stabilizer at 80 to 220 ° C. to an ethylene vinyl acetate copolymer resin to obtain a resin composition, and
(2) mixing the organic peroxide, the crosslinking aid and the silane coupling agent as a crosslinking agent in the ethylene vinyl acetate copolymer resin composition obtained in the step (1) to melt kneading at a temperature below the decomposition temperature of the crosslinking agent to form a sheet. delete delete The method according to claim 1, wherein in step (2), the organic peroxide, the crosslinking aid and the silane coupling agent are mixed with the ethylene vinyl acetate copolymer resin composition obtained in step (1), and then melted below the decomposition temperature of the organic peroxide. A method for producing an ethylene vinyl acetate copolymer sheet for solar cell encapsulant, which is kneaded to form a sheet. The organic peroxide, crosslinking aid and silane coupling agent of claim 1, wherein in step (2), the ethylene vinyl acetate copolymer resin composition obtained in step (1) is melted at or below the decomposition temperature of the organic peroxide in an extruder. A method of manufacturing an ethylene vinyl acetate copolymer sheet for solar cell encapsulation, characterized in that the mixture is fed to the extruder through a separate raw material supply device and melt kneaded to form a sheet. The nanoparticle 0.05-1.0 weight part and the light stabilizer 0.01-0.3 weight part are used with respect to 100 weight part of said ethylene vinyl acetate copolymer resins. The manufacturing method of the ethylene vinyl acetate copolymer sheet for solar cell sealing materials which are used. The ethylene vinyl acetate copolymer resin has a vinyl acetate content of 25 to 32% by weight and a melt index (190 ° C., 2.16 kg) of 6 to 30 g. Method for producing an ethylene vinyl acetate copolymer sheet for solar cell encapsulation material characterized in that / 10 minutes. 6. The ethylene vinyl acetate copolymer according to claim 1, wherein the nanoparticles are at least one member selected from layered clay minerals, titanium dioxide, and zinc oxide. 7. Manufacturing method of the sheet. The method of manufacturing an ethylene vinyl acetate copolymer sheet for solar cell encapsulation according to any one of claims 1 to 4, wherein the light stabilizer is a hindered amine light stabilizer. The method for producing an ethylene vinyl acetate copolymer sheet for solar cell encapsulating materials according to any one of claims 1 to 4, wherein two or more kinds of organic peroxides having different decomposition temperatures are used.