Adhesive film for polarizing plate, polarizing plate including the same and optical display including the same
An adhesive film for a polarizing plate includes a functional group represented by Formula 1: wherein * represents a binding site; A is a C 1 to C 20 aliphatic hydrocarbon group; B is —O—, —S—, a C 1 to C 20 aliphatic hydrocarbon group, or a single bond; R 2 is a C 1 to C 20 aliphatic hydrocarbon group; and n is an integer from 1 to 5.
1. A polarizing plate, comprising:
a polarizer;
an optical film on a lower surface of the polarizer; and
an adhesive film on a lower surface of the optical film, wherein the adhesive film is formed of a composition including a (meth)acrylic copolymer formed using at least a monomer represented by Formula 2:
wherein:
A is a C 1 to C 10 aliphatic hydrocarbon group;
B is —O—;
R 2 is a C 1 to C 10 aliphatic hydrocarbon group;
R 1 is hydrogen or a C 1 to C 5 alkyl group; and n is an integer from 1 to 5,
the monomer represented by Formula 2 is present in an amount of about 50 wt % to about 96 wt % in the (meth)acrylic copolymer, and
the adhesive film has a photoelastic coefficient from about −120×10 −12 m 2 /N to about 120×10 −12 m 2 /N, as measured at about 23° C. and at a wavelength of about 590 nm.
2. The polarizing plate as claimed in claim 1 , wherein the (meth)acrylic copolymer includes a copolymer formed of a mixture of the monomer represented by Formula 2, an alkyl group-containing vinyl monomer, a carboxylic acid group-containing vinyl monomer, a hydroxyl group-containing vinyl monomer, and an amide group-containing vinyl monomer.
3. The polarizing plate as claimed in claim 2 , wherein the mixture includes:
about 50 wt % to about 96 wt % of the monomer represented by Formula 2;
about 0.1 wt % to about 30 wt % of the alkyl group-containing vinyl monomer;
about 0.001 wt % to about 10 wt % of the carboxylic acid group-containing vinyl monomer;
about 0.1 wt % to about 10 wt % of the hydroxyl group-containing vinyl monomer; and
about 0.1 wt % to about 10 wt % of the amide group-containing vinyl monomer.
4. The polarizing plate as claimed in claim 3 , wherein the mixture further includes an aromatic group-containing vinyl monomer.
5. The polarizing plate as claimed in claim 4 , wherein the mixture includes:
about 50 wt % to about 96 wt % of the monomer represented by Formula 2;
about 0.1 wt % to about 20 wt % of the alkyl group-containing vinyl monomer;
about 0.001 wt % to about 10 wt % of the carboxylic acid group-containing vinyl monomer;
about 0.1 wt % to about 10 wt % of the hydroxyl group-containing vinyl monomer;
about 0.1 wt % to about 10 wt % of the amide group-containing vinyl monomer; and
about 0.1 wt % to about 14 wt % of the aromatic group-containing vinyl monomer.
6. The polarizing plate as claimed in claim 1 , wherein the composition further includes at least one of a crosslinking agent and a silane coupling agent.
7. The polarizing plate as claimed in claim 6 , wherein the crosslinking agent includes an isocyanate crosslinking agent.
8. The polarizing plate as claimed in claim 6 , wherein the silane coupling agent includes an epoxy structure.
9. The polarizing plate as claimed in claim 6 , wherein the composition includes about 70 wt % to about 99.5 wt % of the copolymer, about 0.1 wt % to about 20 wt % of the crosslinking agent, and about 0.1 wt % to about 10 wt % of the silane coupling agent in terms of solid content.
10. The polarizing plate as claimed in claim 1 , wherein the adhesive film has a thickness of greater than 0 μm and less than or equal to about 100 μm.
11. The polarizing plate as claimed in claim 1 , further comprising an optical film on an upper surface of the polarizer.
12. The polarizing plate as claimed in claim 11 , wherein the optical film is a triacetyl cellulose film, and the adhesive film directly contacts the triacetyl cellulose film.
13. The polarizing plate as claimed in claim 1 , wherein the polarizing plate has a light leakage value (ΔL) from about 0 to about 0.4, as represented by Equation 1:
Δ L =[( a+b+d+e )/4] /c− 1 [Equation 1]
wherein a, b, d and e represent a brightness at midpoints of respective sides of a panel upon which the polarizing plate is stacked, and c is brightness at a central site of the panel upon which the polarizing plate is stacked.
14. An optical display including the polarizing plate as claimed in claim 1 .