Encapsulant film

1. An encapsulant film having a ratio (S a /S m ) of 0.6 or more, of a peak area (S a ) of silanol groups and amine groups in a wavenumber range of 3,100 cm −1 to 3,600 cm −1 to a peak area (S m ) of methylene groups in a wavenumber range of 705 cm −1 to 735 cm −1 , as measured by FT-IR using an attenuated total reflection (ATR) method, and comprising a copolymer which is formed from a composition comprising:

an olefin resin;

an unsaturated silane compound; and

an aminosilane compound,

wherein the aminosilane compound is included in an amount of 1 to 40 parts by weight with respect to 100 parts by weight of the silane compound in the composition.

2. The encapsulant film of claim 1 , wherein the ratio (S a /S m ) of the peak area (S a ) of the silanol groups and amine groups to the peak area (S m ) of the methylene groups is 0.9 or more.

3. The encapsulant film of claim 1 , which satisfies the following Equation 1:

P=α 1 ( T L −100)+β 1   [Equation 1]

wherein P represents a peel strength of an encapsulant to a glass substrate as measured at a peel angle of 90° and a peel rate of 50 mm/min;

T L represents a lamination temperature of the encapsulant and the glass substrate;

α 1 is greater than or equal to 1; and

β 1 is greater than or equal to 40.

4. The encapsulant film of claim 3 , wherein α 1 is in a range of 1.5 to 4, and β 1 is in a range of 50 to 150.

5. The encapsulant film of claim 3 , wherein α 1 is in a range of 2.3 to 3.3, and β 1 is in a range of 70 to 130.

6. The encapsulant film of claim 1 , wherein the peel strength of the encapsulant film to the glass substrate is greater than or equal to 50 N/15 mm, as measured at a peel angle of 90° and a peel rate of 50 mm/min after the encapsulant film is laminated on the glass substrate at a temperature of 110° C.

7. 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(1.28 X CIE −1.06 Z CIE )]/ Y CIE   [Equation 2]

wherein YI is a value calculated by a UV/Vis spectrometer using a color difference analysis program, and X CIE , Y CIE and Z CIE are relative values represented by red, green, and blue color coordinates, respectively.

8. The encapsulant film of claim 7 , wherein the yellowness index (YI) value is in a range of 1.0 to 1.5.

9. The encapsulant film of claim 1 , wherein the copolymer comprises:

a main chain comprising a polymerization unit of an olefin-based monomer; and

a branched chain bound to the main chain and represented by the following Formula 1:

—SiR 1 l R 2 (2-l) R 3   [Formula 1]

wherein R 1 and R 2 each independently represent a halogen, an amine group, —R 4 R 5 , or —R 5 bound to a silicon atom;

R 4 represents oxygen, or a sulfur atom;

R 5 represents hydrogen, an alkyl group, an aryl group, an aralkyl group, or an acyl group;

1 is an integer of 1 or 2;

R 3 represents —OSiR 6 m R 7 (2-m) R 8 bound to a silicon atom;

R 6 and R 7 each independently represent a halogen, an amine group, —R 9 R 10 , or —R 10 bound to a silicon atom;

R 9 represents oxygen, or a sulfur atom;

R 10 represents hydrogen, an alkyl group, an aryl group, an aralkyl group, or an acyl group;

R 8 represents —(CH 2 ) n NR 11 R 12 bound to a silicon atom;

R 11 and R 12 each independently represent a halogen or R 13 NH 2 bound to a silicon atom;

R 13 represents alkylene group;

m is an integer of 1 or 2; and

n is an integer greater than or equal to 0.

10. The encapsulant film of claim 9 , wherein R 1 and R 2 each independently represent a hydroxyl group;

R 3 represents —OSiR 6 m R 7 (2-m) R 8 bound to the silicon atom;

R 6 and R 7 each independently represent a hydroxyl group;

R 8 represents —(CH 2 ) n NR 11 R 12 bound to the silicon atom;

R 11 represents hydrogen;

R 12 represents R 13 NH 2 ; and

R 13 represents alkylene group.

11. The encapsulant film of claim 9 , wherein the copolymer further comprises a branched chain bound to the main chain and represented by the following Formula 2:

—SiR 14 o R 15 ( 3-o )  [Formula 2]

wherein R 14 and R 15 each independently represent a halogen, an amine group, —R 16 R 17 , or —R 17 bound to a silicon atom;

R 16 represents oxygen, or a sulfur atom;

R 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.

12. The encapsulant film of claim 11 , wherein R 14 and R 15 each independently represent a hydroxyl group or —R 16 R 17 bound to a silicon atom;

R 16 represents oxygen; and

R 17 represents an alkyl group.

13. An optoelectronic device comprising:

a front substrate;

a back sheet;

the encapsulant film stacked between the front substrate and the back sheet as defined in claim 1 ; and

an optoelectronic element encapsulated by the encapsulant film.