Adhesive film for polarizing plate, adhesive composition for the same, polarizing plate comprising the same and optical display comprising the same
An adhesive composition for a polarizing plate, an adhesive film formed from the same, a polarizing plate including the same, and an optical display including the same are disclosed. The adhesive film for a polarizing plate is formed from an adhesive composition including an epoxy compound and a (meth)acrylate compound, and the adhesive film has an FT-IR peak ratio of about 0.015 or lower as defined by Equation 1. Equation 1 FT-IR peak ratio= B/A (1) In Equation 1, A is the peak height of the peak attributable to the —(C═O)— bond at 1724 cm −1 , and B is the peak height of the peak attributable to the —CH═CH— bond at 1636 cm −1 .
1. An adhesive film for a polarizing plate, the adhesive film being formed from an adhesive composition for a polarizing plate comprising an epoxy component and a (meth)acrylate component, the epoxy component comprising a first epoxy compound having a first glass transition temperature and a second epoxy compound having a second glass transition temperature, the second glass transition temperature being different from the first glass transition temperature by 50° C. or more, wherein the adhesive film has an FT-IR peak ratio of about 0.015 or lower as defined by Equation 1:
Equation 1
FT-IR peak ratio= B/A (1),
wherein A is a peak height attributable to a —(C═O)— bond at 1724 cm −1 and B is a peak height attributable to a —CH═CH— bond at 1636 cm −1 .
2. The adhesive film according to claim 1 , wherein the adhesive film has a glass transition temperature of about 55° C. to about 105° C.
3. The adhesive film according to claim 1 , wherein a weight ratio of the epoxy component to the (meth)acrylate component in the adhesive composition is greater than about 1.
4. The adhesive film according to claim 1 , wherein the first glass transition temperature is about 0° C. to about 150° C. and the second glass transition temperature is about 50° C. to about 200° C.
5. The adhesive film according to claim 1 , wherein the first epoxy compound comprises an epoxy compound containing one aromatic group; and the second epoxy compound comprises at least one of an epoxy compound containing at least two aromatic groups, an alicyclic epoxy compound, a hydrogenated epoxy compound, or an aliphatic epoxy compound.
6. The adhesive film according to claim 5 , wherein the first epoxy compound comprises at least one of phenyl glycidyl ether, resorcinol diglycidyl ether, or butylphenyl glycidyl ether.
7. The adhesive film according to claim 1 , wherein the adhesive composition further comprises a photosensitizer and a photocationic polymerization initiator.
8. The adhesive film according to claim 7 , wherein the adhesive composition comprises:
about 0.1 parts by weight to about 10 parts by weight of the photosensitizer based on a total of 100 parts by weight of a sum of about 40 wt % to about 90 wt % of the epoxy component and about 10 wt % to about 60 wt % of the (meth)acrylate component in terms of solids content; and
about 0.1 parts by weight to about 10 parts by weight of the photocationic polymerization initiator based on a total of 100 parts by weight of a sum of about 40 wt % to about 90 wt % of the epoxy component and about 10 wt % to about 60 wt % of the (meth)acrylate component in terms of solids content.
9. The adhesive film according to claim 1 , wherein the first epoxy compound is present in the epoxy component in an amount of about 1 wt % to about 30 wt %, and the second epoxy compound is present in the epoxy component in an amount of about 70 wt % to about 99 wt %.
10. The adhesive film according to claim 1 , wherein the (meth)acrylate component comprises a hydroxyl group-containing monofunctional acrylate.
11. The adhesive film according to claim 10 , wherein the (meth)acrylate component further comprises a C 1 to C 10 alkyl group-containing (meth)acrylate substituted with a C 6 to C 10 aryloxy group.
12. A polarizing plate, comprising the adhesive film for a polarizing plate according to claim 1 .
13. An optical display, comprising the polarizing plate according to claim 12 .