Polarizing plate
The present application relates to a polarizing plate and a liquid crystal display device. The polarizing plate which is thin and light, meets requirements for physical properties such as durability, moisture resistance, workability and light leakage inhibiting ability, and has an antistatic property, and the liquid crystal display device including the same may be provided.
1. A polarizing plate, comprising:
a polarizer;
a pressure-sensitive adhesive layer; and
a polyvinyl alcohol adhesive layer disposed between the polarizer and the pressure-sensitive adhesive layer;
wherein the pressure-sensitive adhesive layer disposed on at least one surface of the polyvinyl alcohol adhesive layer has different peeling strengths with respect to glass at a first surface that is directly adjacent to the polyvinyl alcohol adhesive layer and a second surface that is an opposite to the first surface, a ratio(P 2 /P 1 ) of the peeling strength with respect to glass of the second surface(P 2 ) to the peeling strength with respect to glass of the first surface(P 1 ) being 8.33 to 30, and a surface resistance being 2.1×10 9 Ω/square to 2.7×10 9 Ω/square,
wherein the pressure-sensitive adhesive layer is a layer of a pressure sensitive adhesive composition comprising an acryl polymer and an antistatic agent,
wherein the antistatic agent is present in an amount from 0.1 to 2 parts by weight relative to 100 parts by weight of the acryl polymer,
wherein the pressure-sensitive adhesive layer has a thickness of 40 μm to 60 μm, and
an average tensile modulus of the pressure-sensitive adhesive layer is 90 to 1,000 MPa at a temperature ranging from 10° C. to 40° C., and
a peeling strength at a temperature ranging from 10° C. to 40° C. of the second surface in the pressure-sensitive adhesive layer with respect to glass is 100 to 2,500 gf/25 mm.
2. The polarizing plate of claim 1 , wherein the pressure-sensitive adhesive layer has an interpenetrating polymer network(IPN) structure.
3. The polarizing plate of claim 1 , wherein the pressure-sensitive adhesive layer has a tensile modulus that varies in a thickness direction.
4. The polarizing plate of claim 1 , wherein a peeling strength at a temperature ranging from 10° C. to 40° C. with respect to glass of the first surface that is adjacent to the polarizer in the pressure-sensitive adhesive layer is 5 to 100 gf/25 mm.
5. The polarizing plate of claim 1 , wherein the acryl polymer comprises a polymerization unit derived from 70 to 99.9 parts by weight of an alkyl (meth)acrylate, 1 to 14 parts by weight of a compound of Formula 1, and 0.1 to 30 parts by weight of a copolymerizable monomer having a polar group:
where R is hydrogen or an alkyl group, A is an alkylene group or an alkylidene group, R 1 is an alkyl group or an aryl group, and n is a number between 1 and 50.
6. The polarizing plate of claim 5 , wherein the copolymerizable monomer having a polar group comprises a polymerization unit derived from 0.1 to 20 parts by weight of a copolymerizable monomer having a hydroxyl group, and 0.5 to 10 parts by weight of a copolymerizable monomer having an acid group.
7. The polarizing plate of claim 1 , wherein the antistatic agent is an inorganic salt or organic salt.
8. The polarizing plate of claim 7 , wherein the inorganic salt comprises an alkali metal cation or an alkali earth metal cation.
9. The polarizing plate of claim 7 , wherein the organic salt comprises an onium cation.
10. The polarizing plate of claim 1 , wherein the pressure-sensitive adhesive composition further comprises a multifunctional crosslinking agent.
11. The polarizing plate of claim 1 , wherein the pressure-sensitive adhesive composition further comprises an active energy ray-polymerizable compound.
12. The polarizing plate of claim 1 , wherein the pressure-sensitive adhesive composition further comprises an ultraviolet (UV) absorbent.
13. The polarizing plate of claim 1 , wherein the pressure-sensitive adhesive composition further comprises a compound of Formula 2:
where M 1 to M 5 are each independently R 1 —N, (R 2 )(R 3 )—C or (R 4 )(R 5 )—C, in which R 1 is a hydrogen atom, an alkyl group or an alkoxy group, R 2 and R 3 are each independently an alkyl group, R 4 and R 5 are each independently a hydrogen atom or an alkyl group, L is an alkylene group or an alkylidene group, and P is an alkyl group or a substituent of Formula 3, and in Formula 2, at least one of M 2 to M 4 is the R 1 —N, and the M 1 , M 2 , M 3 , M 4 or M 5 immediately adjacent to the at least one of M 2 to M 4 that is the R 1 —N is the (R 2 )(R 3 )—C:
where M 6 to M 10 are each independently R 1 —N, (R 2 )(R 3 )—C or (R 4 )(R 5 )—C, and here, R 1 is a hydrogen atom, an alkyl group or an alkoxy group, R 2 and R 3 are each independently an alkyl group, and R 4 and R 5 are each independently a hydrogen atom or an alkyl group, and in Formula 3, at least one of M 7 to M 9 is the R 1 —N, and the M 6 , M 7 , M 8 , M 9 or M 10 immediately adjacent to the at least one of M 7 to M 9 that is the R 1 —N is the (R 2 )(R 3 )—C.
14. A liquid crystal display device in which the polarizing plate of claim 1 is attached to one or both sides of a liquid crystal panel by the pressure-sensitive adhesive layer.
15. The liquid crystal display device of claim 14 , wherein the liquid crystal panel is a twisted nematic (TN) panel.