Encapsulant film

Abstract

Embodiments of the present application relate to an encapsulant film, a method for manufacturing an encapsulant film, an optoelectronic device, and a method for manufacturing an optoelectronic device, and can provide superior adhesive force with a front substrate and a back sheet, and specifically having long-term adhesive and heat resistance properties. Also, the present application can provide the encapsulant which does not have a negative effect on parts, such as optoelectronic elements or wire electrodes encapsulated in the optoelectronic devices, and on a working environment, and which can maintain superior workability and economic feasibility in device manufacturing.

Claims

1. An encapsulant film, comprising: a copolymer comprising a main chain, said main chain comprising a polymerization unit derived from an olefin-based monomer; and branched chains bound to the main chain, wherein a silanol group and an amine group are present in one or more of the branched chains, and wherein the encapsulant film has a peel strength of 160 N/15 mm or more when the encapsulant film is disposed on a glass substrate, as measured at a peel angle of 90 and a peel rate of 50 mm/min according to ASTM D1897.

2. The encapsulant film of claim 1, wherein the encapsulant film has a peel strength of 180 N/15 mm or more with respect to the glass substrate, as measured at a peel angle of 90 and a peel rate of 50 mm/min according to ASTM D1897.

3. The encapsulant film of claim 1, wherein a yellowness index (YI) value is in a range of 0.5 to 2.5, as calculated by measuring a reflectance in a wavelength region of 400 nm to 700 nm using a UV/Vis spectrometer according to the ASTM D1925 standard and applying the reflectance to the following Equation 2:
YI=[100(1.28X.sub.CIE1.06Z.sub.CIE)]/Y.sub.CIE[Equation 2] wherein YI is a value calculated by a UV/Vis spectrometer using a color difference analysis program, and X.sub.CIE, Y.sub.CIE and Z.sub.CIE are relative values represented by red, green, and blue color coordinates, respectively.

4. The encapsulant film of claim 1, wherein a ratio (S.sub.a/S.sub.m) of a peak area (S.sub.a) of silanol groups and amine groups in the film in a wavenumber range of 3,100cm.sup.1 to 3,600 cm.sup.1 to a peak area (S.sub.m) of methylene groups in a wavenumber range of 705 cm.sup.1 to 735 cm.sup.1 is 0.6 or more, as measured by FT-IR using an attenuated total reflection (ATR) method.

5. The encapsulant film of claim 4, wherein the ratio (S.sub.a/S.sub.m) of the peak area (S.sub.a) of the silanol groups and the amine groups to the peak area (S.sub.m) of the methylene groups is 0.9 or more.

6. The encapsulant film of claim 1, wherein the branched chains comprise the following Formula 1:
SiR.sup.1.sub.1R.sup.2.sub.(2l)R.sup.3[Formula 1] wherein R.sup.1 and R.sup.2 each independently represent a halogen, an amine group, R.sup.4R.sup.5, or R.sup.5 being bound to a silicon atom; R.sup.4 represents oxygen, or a sulfur atom; R.sup.5 represents hydrogen, an alkyl group, an aryl group, an aralkyl group, or an acyl group; lis an integer of 1 or 2; R.sup.3 represents OSiR.sup.6.sub.mR.sup.7.sub.(2m)R.sup.8 bound to a silicon atom; R.sup.6 and R.sup.7 each independently represent a halogen, an amine group, R.sup.9R.sup.10, or R.sup.10 bound to a silicon atom; R.sup.9 represents oxygen, or a sulfur atom; R.sup.10represents hydrogen, an alkyl group, an aryl group, an aralkyl group, or an acyl group; R.sup.8 represents (CH.sub.2).sub.nNR.sup.11R.sup.12 bound to a silicon atom; R.sup.11 and R.sup.12 each independently represent hydrogen, or R.sup.13NH.sub.2 bound to a nitrogen atom; R.sup.13 represents alkylene group; m is an integer of 1 or 2; and n is an integer greater than or equal to 0.

7. The encapsulant film of claim 6, wherein R.sup.1 and R.sup.2 each independently represent a hydroxyl group; R.sup.3 represents OSiR.sup.6.sub.mR.sup.7(.sub.2m)R.sup.8 bound to the silicon atom; R.sup.6 and R.sup.7 each independently represent a hydroxyl group; R.sup.8 represents (CH.sub.2).sub.n NR.sup.11R.sup.12 bound to the silicon atom; R.sup.11 represents hydrogen; R.sup.12 represents R.sup.13NH.sub.2, and R.sup.13 represents an alkylene group.

8. The encapsulant film of claim 6, wherein the copolymer further comprises a branched chain bound to the main chain and represented by the following Formula 2:
SiR.sup.14.sub.oR.sup.15(.sub.3o) [Formula 2] wherein R.sup.14 and R.sup.15 each independently represent a halogen, an amine group, R.sup.16R.sup.17, or R.sup.17 bound to a silicon atom; R.sup.16 represents oxygen, or a sulfur atom; R.sup.17 represents hydrogen, an alkyl group, an aryl group, an aralkyl group, or an acyl group; and o is an integer ranging from 1 to 3.

9. The encapsulant film of claim 8, wherein R.sup.14 and R.sup.15 each independently represent a hydroxyl group or R.sup.16R.sup.17 bound to a silicon atom; R.sup.16 represents oxygen; and R.sup.17 represents an alkyl group.

Description

DESCRIPTION OF DRAWINGS

(1) FIGS. 1 and 2 are schematic cross-sectional views showing a photovoltaic module that is an optoelectronic device according to one exemplary embodiment of the present application.

(2) FIG. 3 is a graph illustrating adhesive strengths of encapsulant films manufactured in Examples and Comparative Examples of the present application to a glass substrate according to a lamination temperature.

(3) FIG. 4 is a graph illustrating the results obtained by measuring the encapsulant films manufactured in Examples and Comparative Examples of the present application using Fourier transform infrared spectroscopy (FT-IR).

(4) FIG. 5 is a graph illustrating the results obtained by measuring modified olefin resins prepared in Preparation Examples and Comparative Preparation Examples of the present application using FT-IR.

(5) FIG. 6 is a graph illustrating the UV/Vis spectroscopic results of a sample prepared in Example 3 of the present application.

(6) FIG. 7 is a graph illustrating the UV/Vis spectroscopic results of a sample prepared in Comparative Example 1 of the present application.

BEST MODE

(7) Hereinafter, the present application will be described in detail with reference to Example and Comparative Example of the present application. However, it should be understood that the description proposed herein is not intended to limit the scope of the invention.

(8) <Preparation of modified ethylene/-olefin copolymer>

PREPARATION EXAMPLE 1

(9) 95.01 parts by weight of an ethylene/-olefin copolymer having a density of 0.870 g/cm.sup.3 and an MFR of 5 g/l 10 minutes at a temperature of 190 C. and a load of 2.16 kg, 4.79 parts by weight of vinyltrimethoxysilane (VTMS), 0.1 parts by weight of 3-aminopropyltrimethoxysilane (APTMS), and 0.1 parts by weight of 2,5-bis(t-butylperoxy)-2,5-dimethylhexane (Luperox101) were subjected to grafting reactive extrusion (hot melt stirring) at a temperature of 220 C. and a rotary speed of 180 rpm using a twin-screw extruder to prepare a master batch of a modified ethylene/-olefin copolymer (the term part(s) by weight refers to % by weight, based on a total of 100 parts by weight).

PREPARATION EXAMPLES 2, 3 and 10

(10) Master batches of a modified ethylene/-olefin copolymer were prepared in the same manner as in Preparation Example 1, except that the contents of the vinyltrimethoxysilane and the 3-aminopropyltrimethoxysilane used in Preparation Example 1 were changed as listed in the following Table 1.

PREPARATION EXAMPLES 4 and 5

(11) Master batches of a modified ethylene/-olefin copolymer were prepared in the same manner as in Preparation Example 3, except that 3-aminopropyltriethoxysilane (APTES) and N-[3-(trimethoxysilyl)propyl]ethylenediamine (DAS) were used in Preparation Examples 4 and 5, respectively, instead of the 3-aminopropyltrimethoxysilane used in Preparation Example 3.

PREPARATION EXAMPLES 6 and 7

(12) Master batches of a modified ethylene/-olefin copolymer were prepared in the same manner as in Preparation Examples 1 and 3, respectively, except that an ethylene/-olefin copolymer having a density of 0.882 g/cm.sup.3 and an MFR of 3 g/10 minutes at a temperature of 190 C. and a load of 2.16 kg was used instead of the ethylene/-olefin copolymer used in Preparation Examples 1 and 3.

PREPARATION EXAMPLES 8 and 9

(13) Master batches of a modified ethylene/-olefin copolymer were prepared in the same manner as in Preparation Examples 1 and 3, respectively, except that an ethylene/-olefin copolymer having a density of 0.902 g/cm.sup.3 and an MFR of 3 g/10 minutes at a temperature of 190 C. and a load of 2.16 kg was used instead of the ethylene/-olefin copolymer used in Preparation Examples 1 and 3.

COMPARATIVE PREPARATION EXAMPLE 1

(14) A master batch of a silane-modified ethylene/-olefin copolymer was prepared in the same manner as in Preparation Example 1, except that vinyltrimethoxysilane was used at a content of 4.89 parts by weight without using the 3-aminopropyltrimethoxysilane used in Preparation Example 1.

COMPARATIVE PREPARATION EXAMPLES 2 and 3

(15) Master batches of a silane-modified ethylene/-olefin copolymer were prepared in the same manner as in Preparation Example 3, except that dodecylamine (DA) and trimethoxypropylsilane (TMS) were used in Comparative Preparation Examples 2 and 3, respectively, instead of the 3-aminopropyltrimethoxysilane used in Preparation Example 3.

COMPARATIVE PREPARATION EXAMPLE 4

(16) A master batch of a silane-modified ethylene/-olefin copolymer was prepared in the same manner as in Comparative Preparation Example 1, except that an ethylene/-olefin copolymer having a density of 0.882 g/cm.sup.3 and an MFR of 3 g/10 minutes at a temperature of 190 C. and a load of 2.16 kg was used instead of the ethylene/-olefin copolymer used in Comparative Preparation Example 1.

COMPARATIVE PREPARATION EXAMPLE 5

(17) A master batch of a silane-modified ethylene/-olefin copolymer was prepared in the same manner as in Comparative Preparation Example 1, except that an ethylene/-olefin copolymer having a density of 0.902 g/cm.sup.3 and an MFR of 3 g/10 minutes at a temperature of 190 C. and a load of 2.16 kg was used instead of the ethylene/-olefin copolymer used in Comparative Preparation Example 1.

COMPARATIVE PREPARATION EXAMPLES 6 and 7

(18) Master batches of an ethylene/-olefin copolymer were prepared in the same manner as in Preparation Example 1, except that 3-aminopropyltrimethoxysilane was used at contents of 4.89 parts by weight and 0.49 parts by weight, respectively, without using the vinyltrimethoxysilane used in Preparation Example 1.

COMPARATIVE PREPARATION EXAMPLE 8

(19) A master batch of a modified ethylene/-olefin copolymer was prepared in the same manner as in Comparative Preparation Example 1, except that 2.44 parts by weight of the vinyltrimethoxysilane and 2.45 parts by weight of the 3-aminopropyltrimethoxysilane were used instead of 4.79 parts by weight of the vinyltrimethoxysilane and 0.1 parts by weight of the 3-aminopropyltrimethoxysilane used in Preparation Example 1, respectively.

(20) TABLE-US-00001 TABLE 1 Aminosilane content Base resin VTMS Luperox 101 Aminosilane (based on the total (content, density) (content) (content) (content) silane content) Preparation 95.01 wt % 4.79 wt % 0.1 wt % APTMS 2 wt % Example 1 (d = 0.870) 0.1 wt % Preparation 95.01 wt % 4.65 wt % 0.1 wt % APTMS 5 wt % Example 2 (d = 0.870) 0.24 wt % Preparation 95.01 wt % 4.40 wt % 0.1 wt % APTMS 10 wt % Example 3 (d = 0.870) 0.49 wt % Preparation 95.01 wt % 4.40 wt % 0.1 wt % APTES 10 wt % Example 4 (d = 0.870) 0.49 wt % Preparation 95.01 wt % 4.40 wt % 0.1 wt % DAS 10 wt % Example 5 (d = 0.870) 0.49 wt % Preparation 95.01 wt % 4.79 wt % 0.1 wt % APTMS 2 wt % Example 6 (d = 0.882) 0.1 wt % Preparation 95.01 wt % 4.40 wt % 0.1 wt % APTMS 10 wt % Example 7 (d = 0.882) 0.49 wt % Preparation 95.01 wt % 4.79 wt % 0.1 wt % APTMS 2 wt % Example 8 (d = 0.902) 0.1 wt % Preparation 95.01 wt % 4.40 wt % 0.1 wt % APTMS 10 wt % Example 9 (d = 0.902) 0.49 wt % Preparation 95.01 wt % 3.67 wt % 0.1 wt % APTMS 25 wt % Example 10 (d = 0.870) 1.22 wt % Comparative 95.01 wt % 4.89 wt % 0.1 wt % Preparation (d = 0.870) Example 1 Comparative 95.01 wt % 4.40 wt % 0.1 wt % DA Preparation (d = 0.870) 0.49 wt % Example 2 Comparative 95.01 wt % 4.40 wt % 0.1 wt % TMS Preparation (d = 0.870) 0.49 wt % Example 3 Comparative 95.01 wt % 4.89 wt % 0.1 wt % Preparation (d = 0.882) Example 4 Comparative 95.01 wt % 4.89 wt % 0.1 wt % Preparation (d = 0.902) Example 5 Comparative 95.01 wt % 0.1 wt % APTMS 100 wt % Preparation (d = 0.870) 4.89 wt % Example 6 Comparative 95.01 wt % 0.1 wt % APTMS 100 wt % Preparation (d = 0.870) 0.49 wt % Example 7 Comparative 95.01 wt % 2.44 wt % 0.1 wt % APTMS 50 wt % Preparation (d = 0.870) 2.45 wt % Example 8 VTMS: vinyltrimethoxysilane VTMS: vinyltrimethoxysilane APTMS: 3-aminopropyltrimethoxysilane APTES: 3-aminopropyltriethoxysilane DAS: N-[3-(trimethoxysilyl)propyl]ethylenediamine DA: dodecylamine TMS: trimethoxypropylsilane

(21) <Manufacture of Encapsulant and Photovoltaic Cell Module>

EXAMPLES 1 to 5

(22) 18 g of an additive master batch were added to, and mixed with a mixed resin, which was obtained by preparing the master batch of the modified ethylene/-olefin copolymer prepared in each of Preparation Examples 1 to 5, and an ethylene/-olefin copolymer having a density of 0.870 g/cm.sup.3 and an MFR of 5 g/10 minutes at a temperature of 190 C. and a load of 2.16 kg at contents of 200 g and 400 g, respectively, and mixing the master batch of the modified ethylene/-olefin copolymer and the ethylene/-olefin copolymer at a mixing ratio of 1:2, so that a final sheet included a photostabilizer (Uvinul 5050H) at 1,000 ppm, a UV absorbent (TINUVIN UV531) at 1,000 ppm, a first antioxidant (Irganox1010) at 500 ppm, and a second antioxidant (Irgafos168) at 500 ppm. Thereafter, the resulting mixture was introduced into a hopper of a film molding machine provided with a twin-screw extruder ( 19 mm) and a T die (width: 200 mm), and processed at an extrusion temperature of 180 C. and an ejection rate of 3 m/min to prepare a sheet-shaped encapsulant having a thickness of approximately 500 m. A plate glass (thickness: approximately 3 mm), the previously prepared encapsulant having a thickness of 500 m, a photovoltaic device of crystalline silicon wafers, the prepared 500 m-thick encapsulant, and a back sheet (a stacked sheet including a polyvinyl fluoride resin sheet having a thickness of 20 m, polyethylene terephthalate having a thickness of 250 m, and a polyvinyl fluoride resin sheet having a thickness of 20 m; PVDF/PET/PVDF) were laminated in this stacking order, and pressed at 150 C. for 15 minutes 30 seconds in a vacuum laminator to manufacture a photovoltaic cell module.

EXAMPLES 6 and 7

(23) Sheet-shaped encapsulants and photovoltaic cell modules were manufactured in the same manner as in Example 1, except that resins, which were obtained by preparing 200 g of the master batches of the modified ethylene/-olefin copolymer prepared in Preparation Examples 6 and 7 respectively, and 400 g of an ethylene/-olefin copolymer having a density of 0.882 g/cm.sup.3 and an MFR of 3 g/10 minutes at a temperature of 190 C. and a load of 2.16 kg, respectively, and mixing the master batches of the modified ethylene/-olefin copolymer and the ethylene/-olefin copolymer at a mixing ratio of 1:2, were used, respectively, instead of the mixed resin including the master batch of the modified ethylene/-olefin copolymer used in Example 1 and the ethylene/-olefin copolymer.

EXAMPLES 8 and 9

(24) Sheet-shaped encapsulants and photovoltaic cell modules were manufactured in the same manner as in Example 1, except that resins, which were obtained by preparing 200 g of the master batches of the modified ethylene/-olefin copolymer prepared in Preparation Examples 8 and 9 respectively, and 400 g of an ethylene/-olefin copolymer having a density of 0.902 g/cm.sup.3 and an MFR of 3 g/10 minutes at a temperature of 190 C. and a load of 2.16 kg of 3 g/10 minutes, respectively, and mixing the master batches of the modified ethylene/-olefin copolymer and the ethylene/-olefin copolymer at a mixing ratio of 1:2, were used, respectively, instead of the mixed resin including the master batch of the modified ethylene/-olefin copolymer used in Example 1 and the ethylene/-olefin copolymer.

EXAMPLE 10

(25) A sheet-shaped encapsulant and a photovoltaic cell module were manufactured in the same manner as in Example 1, except that a resin, which was obtained by preparing 100 g of the master batch of the modified ethylene/-olefin copolymer prepared in Preparation Example 3, and 500 g of an ethylene/-olefin copolymer having a density of 0.870 g/cm.sup.3 and an MFR of 5 g/10 minutes at a temperature of 190 C. and a load of 2.16 kg, respectively, and mixing the master batch of the modified ethylene/-olefin copolymer and the ethylene/-olefin copolymer at a mixing ratio of 1:5, was used instead of the mixed resin including the master batch of the modified ethylene/-olefin copolymer used in Example 1 and the ethylene/-olefin copolymer.

EXAMPLE 11

(26) A sheet-shaped encapsulant and a photovoltaic cell module were manufactured in the same manner as in Example 1, except that a resin, which was obtained by preparing 54.5 g of the master batch of the modified ethylene/-olefin copolymer prepared in Preparation Example 3, and 545.5 g of an ethylene/-olefin copolymer having a density of 0.870 g/cm.sup.3 and an MFR of 5 g/10 minutes at a temperature of 190 C. and a load of 2.16 kg, respectively, and mixing the master batch of the modified ethylene/-olefin copolymer and the ethylene/-olefin copolymer at a mixing ratio of 1:10, was used instead of the mixed resin including the master batch of the modified ethylene/-olefin copolymer used in Example 1 and the ethylene/-olefin copolymer.

EXAMPLE 12

(27) A sheet-shaped encapsulant and a photovoltaic cell module were manufactured in the same manner as in Example 1, except that a resin, which was obtained by preparing 200 g of the master batch of the modified ethylene/-olefin copolymer prepared in Preparation Example 10, and 400 g of an ethylene/-olefin copolymer having a density of 0.870 g/cm.sup.3 and an MFR of 3 g/10 minutes at a temperature of 190 C. and a load of 2.16 kg, respectively, and mixing the master batch of the modified ethylene/-olefin copolymer and the ethylene/-olefin copolymer at a mixing ratio of 1:2, was used instead of the mixed resin including the master batch of the modified ethylene/-olefin copolymer used in Example 1 and the ethylene/-olefin copolymer.

COMPARATIVE EXAMPLE 1 to 3

(28) Sheet-shaped encapsulants and photovoltaic cell modules were manufactured in the same manner as in Example 1, except that the master batches of the silane-modified ethylene/-olefin copolymer prepared in Comparative Preparation Examples 1 to 3 were used, respectively, instead of the master batch of the modified ethylene/-olefin copolymer used in Example 1.

COMPARATIVE EXAMPLE 4

(29) A sheet-shaped encapsulant and a photovoltaic cell module were manufactured in the same manner as in Example 1, except that a resin, which was obtained by preparing 200 g of the master batch of the silane-modified ethylene/-olefin copolymer prepared in Comparative Preparation Example 4, and 400 g of an ethylene/-olefin copolymer having a density of 0.882 g/cm.sup.3 and an MFR of 3 g/10 minutes at a temperature of 190 C. and a load of 2.16 kg, respectively, and mixing the master batch of the silane-modified ethylene/-olefin copolymer and the ethylene/-olefin copolymer at a mixing ratio of 1:2, was used instead of the mixed resin including the master batch of the modified ethylene/-olefin copolymer used in Example 1 and the ethylene/-olefin copolymer.

COMPARATIVE EXAMPLE 5

(30) A sheet-shaped encapsulant and a photovoltaic cell module were manufactured in the same manner as in Example 1, except that a resin, which was obtained by preparing 200 g of the master batch of the silane-modified ethylene/-olefin copolymer prepared in Comparative Preparation Example 5, and 400 g of an ethylene/-olefin copolymer having a density of 0.902 g/cm.sup.3 and an MFR of 3 g/10 minutes at a temperature of 190 C. and a load of 2.16 kg, respectively, and mixing the master batch of the silane-modified ethylene/-olefin copolymer and the ethylene/-olefin copolymer at a mixing ratio of 1:2, was used instead of the mixed resin including the master batch of the modified ethylene/-olefin copolymer used in Example 1 and the ethylene/-olefin copolymer.

COMPARATIVE EXAMPLE 6 and 7

(31) Sheet-shaped encapsulants and photovoltaic cell modules were manufactured in the same manner as in Example 1, except that the master batches of the ethylene/-olefin copolymer prepared in Comparative Preparation Examples 6 and 7 were used, respectively, instead of the master batch of the modified ethylene/-olefin copolymer used in Example 1.

COMPARATIVE EXAMPLE 8

(32) A sheet-shaped encapsulant and a photovoltaic cell module were manufactured in the same manner as in Example 1, except that a resin, which was obtained by preparing 200 g of the master batch of the modified ethylene/-olefin copolymer prepared in Comparative Preparation Example 8, and 400 g of an ethylene/-olefin copolymer having a density of 0.870 g/cm.sup.3 and an MFR of 3 g/10 minutes at a temperature of 190 C. and a load of 2.16 kg, respectively, and mixing the master batch of the modified ethylene/-olefin copolymer and the ethylene/-olefin copolymer at a mixing ratio of 1:2, was used instead of the mixed resin including the master batch of the modified ethylene/-olefin copolymer used in Example 1 and the ethylene/-olefin copolymer.

(33) TABLE-US-00002 TABLE 2 Base resin (content, density) Aminosilane Additive Base resin content (based master (content, VTMS Aminosilane on total silane batch density) Content (wt %) (wt %) content) (content) Example 1 400 g (d = 200 g 4.79 wt % APTMS 2 wt % 18 g 0.870) 0.1 wt % Example 2 400 g (d = 200 g 4.65 wt % APTMS 5 wt % 18 g 0.870) 0.24 wt % Example 3 400 g (d = 200 g 4.40 wt % APTMS 10 wt % 18 g 0.870) 0.49 wt % Example 4 400 g (d = 200 g 4.40 wt % APTES 10 wt % 18 g 0.870) 0.49 wt % Example 5 400 g (d = 200 g 4.40 wt % DAS 10 wt % 18 g 0.870) 0.49 wt % Example 6 400 g (d = 200 g 4.79 wt % APTMS 2 wt % 18 g 0.882) 0.1 wt % Example 7 400 g (d = 200 g 4.40 wt % APTMS 10 wt % 18 g 0.882) 0.49 wt % Example 8 400 g (d = 200 g 4.79 wt % APTMS 2 wt % 18 g 0.902) 0.1 wt % Example 9 400 g 200 g 4.40 wt % APTMS 10 wt % 18 g (d = 0.902) 0.49 wt % Example 10 500 g (d = 100 g 4.40 wt % APTMS 10 wt % 18 g 0.870) 0.49 wt % Example 11 545.5 g (d = 54.5 g 4.40 wt % APTMS 10 wt % 18 g 0.870) 0.49 wt % Example 12 400 g (d = 200 g 3.67 wt % APTMS 25 wt % 18 g 0.870) 1.22 wt % Comparative 400 g (d = 200 g 4.89 wt % 18 g Example 1 0.870) Comparative 400 g (d = 200 g 4.40 wt % DA 18 g Example 2 0.870) 0.49 wt % Comparative 400 g (d = 200 g 4.40 wt % TMS 18 g Example 3 0.870) 0.49 wt % Comparative 400 g (d = 200 g 4.89 wt % 18 g Example 4 0.882) Comparative 400 g (d = 200 g 4.89 wt % 18 g Example 5 0.902) Comparative 400 g (d = 200 g APTMS 100 wt % 18 g Example 6 0.870) 4.89 wt % Comparative 400 g (d = 200 g APTMS 100 wt % 18 g Example 7 0.870) 0.49 wt % Comparative 400 g 200 g 2.44 wt % APTMS 50 wt % 18 g Example 8 (d = 0.870) 2.45 wt %

EXPERIMENTAL EXAMPLE

(34) 1. Measurement of 90 Peel Strength

(35) To measure peel strengths of the encapsulants prepared in Examples 1 to 12 and Comparative Examples 1 to 8, specimens similar to the manufactured photovoltaic cell modules were manufactured separately. A specimen was manufactured by stacking a plate glass (thickness: approximately 3 mm), the previously prepared encapsulant having a thickness of 500 m, and a back sheet (a stacked sheet including a polyvinyl fluoride resin sheet having a thickness of 20 m, polyethylene terephthalate having a thickness of 250 m, and a polyvinyl fluoride resin sheet having a thickness of 20 m; PVDF/PET/PVDF) in this stacking order and laminating the stacked components at 150 C. for 15 minutes 30 seconds in a vacuum laminator. Thereafter, the peel strength was measured according to the ASTM D1897 standard by fixing a lower glass plate of the manufactured specimen, and peeling the encapsulant attached to the back sheet together with the back sheet at a tensile speed of 50 mm/min and a peel angle of 90 in a rectangular shape with a width of 15 mm. The measured peel strengths are listed in the following Table 3.

(36) TABLE-US-00003 TABLE 3 Base resin (content, density) Aminosilane Base resin content (based 90 peel (content, VTMS Aminosilane on total silane strength density) Content (wt %) (wt %) content) (N/15 mm) Example 1 400 g 200 g 4.79 wt % APTMS 2 wt % 176.1 (d = 0.870) 0.1 wt % Example 2 400 g 200 g 4.65 wt % APTMS 5 wt % 273.3 (d = 0.870) 0.24 wt % Example 3 400 g 200 g 4.40 wt % APTMS 10 wt % 300.0 (d = 0.870) 0.49 wt % Example 4 400 g 200 g 4.40 wt % APTES 10 wt % 309.3 (d = 0.870) 0.49 wt % Example 5 400 g 200 g 4.40 wt % DAS 10 wt % 205.3 (d = 0.870) 0.49 wt % Example 6 400 g 200 g 4.79 wt % APTMS 2 wt % 369.7 (d = 0.882) 0.1 wt % Example 7 400 g 200 g 4.40 wt % APTMS 10 wt % 302.7 (d = 0.882) 0.49 wt % Example 8 400 g 200 g 4.79 wt % APTMS 2 wt % 180.0 (d = 0.902) 0.1 wt % Example 9 400 g 200 g 4.40 wt % APTMS 10 wt % 350.7 (d = 0.902) 0.49 wt % Example 10 500 g 100 g 4.40 wt % APTMS 10 wt % 228.7 (d = 0.870) 0.49 wt % Example 11 545.5 g 54.5 g 4.40 wt % APTMS 10 wt % 170.0 (d = 0.870) 0.49 wt % Example 12 400 g 200 g 3.67 wt % APTMS 25 wt % 208.3 (d = 0.870) 1.22 wt % Comparative 400 g 200 g 4.89 wt % 77.0 Example 1 (d = 0.870) Comparative 400 g 200 g 4.40 wt % DA 132.1 Example 2 (d = 0.870) 0.49 wt % Comparative 400 g 200 g 4.40 wt % TMS 67.6 Example 3 (d = 0.870) 0.49 wt % Comparative 400 g (d = 200 g 4.89 wt % 97.5 Example 4 0.882) Comparative 400 g (d = 200 g 4.89 wt % 78.0 Example 5 0.902) Comparative 400 g 200 g APTMS 100 wt % 73.4 Example 6 (d = 0.870) 4.89 wt % Comparative 400 g 200 g APTMS 100 wt % 68.0 Example 7 (d = 0.870) 0.49 wt % Comparative 400 g 200 g 2.44 wt % APTMS 50 wt % 162.4 Example 8 (d = 0.870) 2.45 wt %

(37) The average adhesive strengths according to the content range of APS are listed in the following Table 4.

(38) TABLE-US-00004 TABLE 4 Silane master batch VTMS APS APS APS APS APS 100 wt % 2 wt % 5 wt % 10 wt % 25 wt % 50 wt Average 79.9 211.5 264.3 287.0 208.3 162.4 adhesive strength (N/15 mm) Peel EN/BS EN/GL EN/GL EN/GL EN/GL EN/GL tendency EN: Encapsulant GL: Plate glass BS: Back sheet EN/GL: Peeling occurs between encapsulant and plate glass EN/BS: Peeling occurs between encapsulant and back sheet EN/GL + BS: Peeling occurs between encapsulant and plate glass/back sheet

(39) As listed in Table 3, it was revealed that the sheet-shaped encapsulant including the master batch of the modified ethylene/-olefin copolymer prepared using both the vinyltrimethoxysilane and the aminosilane showed a superior adhesive strength, compared to the encapsulant sheets of Comparative Examples 1 and 3 to 7 in which the vinyltrimethoxysilane, the alkylsilane and the aminosilane were used alone, respectively. Also, it was revealed that the sheet-shaped encapsulant showed the highest adhesive strength when the master batch of the modified ethylene/-olefin copolymer and the non-modified ethylene/-olefin copolymer were present at a mixing ratio of 1:2. In the case of Comparative Example 2 in which the alkylamine was used alone, the initial peel strength was able to be maintained to at least a certain level, but long-term durability was likely to be degraded due to the alkylamine remaining in the system, which resulted in a potential decrease in the peel strength measured after being kept under severe conditions.

(40) As listed in Table 4, it was also confirmed that the average adhesive strength was greater than or equal to approximately 200 N/15 mm when the aminosilane compound in the olefin resin composition was present in a content range of 2 to 25% by weight, indicating that the sheet-shaped encapsulant showed a superior adhesive strength.

(41) That is, according to Examples 1 to 12 and Comparative Examples 1 to 8, and Experimental Examples using the encapsulants prepared in Examples 1 to 12 and Comparative Examples 1 to 8, it could be seen that the adhesive strengths to the back sheet formed on the encapsulant and the glass substrate formed below the encapsulant were superior when the master batch of the ethylene/-olefin copolymer modified with both the vinylsilane and the aminosilane was used in a certain content range together with the non-modified ethylene/-olefin copolymer, compared to when the vinylsilane, the alkylamine, the aminosilane, or the alkylsilane was used alone.

(42) 2. Measurement of 90 Peel Strength with a Change in Lamination Condition

(43) The 90 peel strengths were measured in the same manner as in Experimental Example 1, except that the lamination conditions used in Experimental Example 1 upon manufacture of specimens similar to the photovoltaic cell modules manufactured with the encapsulants of Examples 1 and 3 were changed as listed in the following Table 5, and the lamination process was performed at temperatures of 110 C., 130 C., 140 C., 150 C., and 160 C. for 6 minutes 30 seconds, 10 minutes 30 seconds, and 15 minutes 30 seconds, respectively. The measured 90 peel strengths are listed in the following Table 5, and a graph obtained by plotting the adhesive strengths measured according to the lamination temperature is shown in FIG. 3.

(44) Also, the 90 peel strengths were measured in the same manner as in Experimental Example 1, except that the lamination conditions used in Experimental Example 1 upon manufacture of specimens similar to the photovoltaic cell module manufactured with the encapsulant of Comparative Example 1 were changed as listed in the following Table 5, and the lamination process was performed at temperatures of 110 C., 130 C., 140 C., 150 C., and 160 C. for 6 minutes 30 seconds, 10 minutes 30 seconds, and 15 minutes 30 seconds, respectively. The measured 90 peel strengths are listed in the following Table 5, and a graph obtained by plotting the adhesive strengths measured according to the lamination temperature is shown in FIG. 3.

(45) TABLE-US-00005 TABLE 5 90 Peel strengths (N/15 mm) Vacuum for 2 Vacuum for 3 Vacuum for 5 Lami- min/pressed for min/pressed for min/pressed for nation 30 sec/pressure 30 sec/pressure 30 sec/pressure con- retained for retained for retained for dition 4 min 7 min 10 min Comparative 110 C. 9.0 8.5 22.5 Example 1 130 C. 17.8 25.6 39.0 140 C. 22.5 38.3 50.4 150 C. 34.2 62.0 79.9 160 C. 67.5 67.9 70.0 Example 1 110 C. 63.0 86.4 96.3 130 C. 64.9 115.8 145.6 140 C. 99.0 153.7 167.8 150 C. 126.8 186.5 211.5 160 C. 184.8 246.9 305.0 Example 3 110 C. 106.3 139.9 159.7 130 C. 176.0 213.7 181.9 140 C. 205.5 294.3 214.0 150 C. 326.7 296.3 287.0 160 C. 324.7 336.0 323.0

(46) As listed in Table 5, it was revealed that the encapsulants had excellent adhesive strengths even under various conditions such as lamination temperature and time in the case of Examples 1 and 3 in which the aminosilane was used together with the vinyltrimethoxysilane, compared to Comparative Example 1 in which the vinyltrimethoxysilane was used alone. Also, it could be seen that the encapsulants had excellent adhesive strengths of 50 N/15 mm or more even when laminated at a low lamination temperature of 110 C.

(47) 3. Measurement of Yellowness Index (YI)

(48) The encapsulant films for optoelectronic devices manufactured in Examples and Comparative Examples were measured for reflectance in a wavelength range of 400 nm to 700 nm using Colorflex (Hunter lab) according to the ASTM 1925 standard, and YI values were calculated from the measured reflectance values (see the following Equation 2).
YI=[100(1.28X.sub.CIE1.06Z.sub.CIE)]/Y.sub.CIE[Equation 2]

(49) In Equation 2, YI is a value calculated by a UV/Vis/NIR spectrometer using a color difference analysis program (ASTM, D1925), and X.sub.CIE, Y.sub.CIE and Z.sub.CIE are relative values represented by red, green and blue color coordinates, respectively.

(50) The YI values according to the content of APS are listed in the following Table 6.

(51) TABLE-US-00006 TABLE 6 Silane master batch VTMS APS APS APS APS APS 100 wt % 2 wt % 5 wt % 10 wt % 25 wt % 50 wt % YI value 0.98 1.23 1.25 1.43 2.49 2.7

(52) As listed in Table 6, it was revealed that the YI values increased when the aminosilane compound was included at an excessive content in the silane compound of the entire silane master batch.

(53) 4. IR Analysis

(54) To detect a branched chain including a moiety in which hydrocarbon groups of some silyl groups were converted into hydroxyl groups and also including a moiety containing an amine functional group in a modified master batch, and to measure a level of conversion of methoxysilyl groups (SiOCH.sub.3) into silanol groups (SiOH) as the hydrolysis was promoted by the aminosilane compound during lamination of the encapsulant film, the modified master batches prepared in Preparation Examples 1 to 3 and Comparative Preparation Examples 1 and the encapsulant films prepared in Examples 1 to 3 and Comparative Examples 1 were measured for a peak area of methylene groups (CH.sub.2) and a peak area of silanol groups (SiOH) and amine groups (NH.sub.2) in the modified master batches and the encapsulants. Each of the peak areas was measured under the following conditions using the following method.

(55) Diamond/zinc selenide (ZnSe) and each of the manufactured modified master batches and encapsulant specimens were closely adhered to each other in an ATR mode using Varian 660-IR, the incident light was irradiated from the side of the diamond/zinc selenide at an incidence angle of 45 to measure absorbance ratio of infrared rays with a region of wavelength 600 cm.sup.1 to 4,000 cm.sup.1, and each peak area was measured using the measured absorption ratio. In this case, the peak value may be an average of values from measuring the reflected light 32 times. The peak area of the silanol groups (SiOH) and amine groups (NH.sub.2) was calculated by setting a baseline in a wavenumber range of 2,400 cm.sup.1 to 3,800 cm.sup.1 and integrating the peak area in a wavenumber range of 3,100 cm.sup.1 to 3,600 cm.sup.1, and the peak area of the methylene groups (CH.sub.2) was calculated by setting a baseline in a wavenumber range of 690 cm.sup.1 to 760 cm.sup.1 and integrating the peak area in a wavenumber range of 705 cm.sup.1 to 735 cm.sup.1.

(56) <Measurement Conditions>

(57) Number of illuminations: 32

(58) Resolution: 4

(59) The measurement results of the encapsulant films are listed in the following Table 7 and shown in FIG. 4, and the measurement results of the modified master batches are listed in the following Table 8 and shown in FIG. 5.

(60) TABLE-US-00007 TABLE 7 SiOH & NH.sub.2 CH.sub.2 APS peak area peak area Area ratio Sample content (S.sub.a) (S.sub.m) (S.sub.a/S.sub.m) Example 1 2 wt % 1.44 1.61 0.90 Example 2 5 wt % 2.00 1.58 1.26 Example 3 10 wt % 3.04 1.51 2.00 Comparative VTMS 0.93 1.62 0.57 Example 1 100%

(61) TABLE-US-00008 TABLE 8 SiOH & NH.sub.2 CH.sub.2 APS peak area peak area Area ratio Sample content (S.sub.a) (S.sub.m) (S.sub.a/S.sub.m) Preparation 2 wt % 4.55 1.58 2.89 Example 1 Preparation 5 wt % 7.80 1.48 5.27 Example 2 Preparation 10 wt % 8.85 1.12 7.90 Example 3 Comparative VTMS 1.70 1.64 1.04 Preparation 100% Example 1

(62) 5. Measurement of Light Transmittance

(63) To measure light transmittances of the encapsulants prepared in Example 3 and Comparative Example 1, additional specimens were prepared. A specimen was prepared by inserting the two previously prepared encapsulants having a thickness of 500 m between two slide glasses for an optical microscope (thickness: approximately 1 mm), and laminating the encapsulants in a vacuum laminator under lamination temperature conditions as listed in the following Table 9. In this case, the specimen was prepared so that the sum of the thicknesses of the two overlapping encapsulant sheets became approximately 50050 m using a guide, and measured for total light transmittance and haze with respect to light at a wavelength of 550 nm using a hazemeter. The measured total light transmittance and haze values are listed in the following Table 9. In this case, the transmittance and haze values were calculated as averages of values measured in triplicate after the specimen was loaded into a specimen holder, and measured under conditions according to the JIS K 7105 standard. The lamination time was constant: under a vacuum for 5 min/pressed for 30 sec/pressure retained for 10 min.

(64) <Measuring Conditions Using UV/Vis Spectroscopic Machine>

(65) Slit width: 32 nm

(66) Detector unit: External (2D detectors)

(67) Time constant: 0.2 sec

(68) TABLE-US-00009 TABLE 9 Lamination Vacuum for 5 min/pressed for 30 sec/ conditions pressure retained for 10 min Temperature Tt (%) Td (%) Haze (%) Comparative 110 C. 92.1 0.6 0.7 Example 1 130 C. 91.5 2.4 2.6 150 C. 91.4 2.8 3.1 Example 3 110 C. 92.2 0.6 0.7 130 C. 91.3 2.8 3.1 150 C. 91.5 2.9 3.2

(69) As listed in Table 9 and shown in FIGS. 6 and 7, it was revealed that the samples which were laminated at a low temperature of 110 C. regardless of the presence of the aminosilane showed low haze and high total light transmittance.

(70) As a result, it could be seen that the encapsulant had a low adhesive strength at a lamination temperature of 110 C., and thus, was unable to be used as a solar encapsulant in the case of Comparative Example 1 in which the vinyltrimethoxysilane was used alone, but the encapsulant showed a high adhesive strength and excellent light transmittance even at a low lamination temperature in the case of Example 3 in which the aminosilane was added.