KR102126055B1 - Polarizing plate and optical display apparatus comprising the same - Google Patents

Abstract

A polarizer, a protective layer formed on the upper surface of the polarizer, and a barrier layer formed on the lower surface of the polarizer, wherein the barrier layer includes a conductive polymer, a cellulose ester, a hydroxyl group-containing (meth)acrylate, a reactive unsaturated compound, and an initiator. A polarizing plate formed of a composition for a barrier layer and an optical display device including the same are provided.

Description

Polarizing plate and optical display device including the same {POLARIZING PLATE AND OPTICAL DISPLAY APPARATUS COMPRISING THE SAME}

The present invention relates to a polarizing plate and an optical display device including the same. More specifically, the present invention is a protective layer, a polarizer, a polarizing plate sequentially formed with a barrier layer, the adhesion between the polarizer and the barrier layer is excellent, the barrier layer has a static dissipative (static dissipative) effect and excellent optical transparency And, to provide a polarizing plate excellent in durability at high temperature or high temperature and high humidity.

The liquid crystal display device includes a liquid crystal panel and polarizing plates formed on both sides of the liquid crystal panel. The polarizing plate includes a polarizer and a protective film formed on both sides of the polarizer. Recently, a polarizing plate is thinned by forming a protective film on one surface of the polarizer and a coating layer on the other surface of the polarizer.

Polarizers are susceptible to moisture and even more susceptible to moisture at high temperatures. At high temperature and high humidity, the polarizing plate may be less durable due to external moisture penetration, and the polarity of the polarizer may be deteriorated. Polarizing plates having improved durability at high temperatures have been developed. However, high temperature/high humidity is a harsher condition than high temperature, and the polarizer is susceptible to moisture. Therefore, even in a polarizer having high durability at high temperatures, there is a limit in improving durability even at high temperature/high humidity.

On the other hand, when the polarizing plate is attached to the liquid crystal panel, the release film is removed and then attached to the surface of the liquid crystal panel by the adhesive layer. At this time, when the release film is removed or the protective film is peeled off, the film may be damaged by static electricity. In addition, when a foreign substance exists between each layer, an abnormal display occurs on the screen of the optical display device, and there is a problem in that a normal liquid crystal display is not performed or malfunctions during operation.

As a method for preventing this, a method of forming a conductive layer on the protective film of the polarizing plate, using a conductive adhesive or a conductive adhesive, or using a conductive protective film may be considered. However, in this method, the optical transparency of the film may be lowered and the adhesiveness of the film may be lowered. In addition, the conductive performance may be lowered or the foaming phenomenon may be exhibited by temperature and/or humidity, which is not sufficient for use.

Background art of the present invention is disclosed in Korean Patent Publication No. 2010-0018462.

An object of the present invention is to provide a polarizing plate comprising a barrier layer having excellent adhesion to a polarizer and having an antistatic effect.

Another object of the present invention is to provide a polarizing plate comprising an optically transparent barrier layer.

Another object of the present invention is to provide a polarizing plate having good durability at high temperature and high humidity.

The polarizing plate of the present invention includes a polarizer, a protective layer formed on the upper surface of the polarizer, and a barrier layer formed on the lower surface of the polarizer, wherein the barrier layer is a conductive polymer, cellulose ester, hydroxyl group-containing (meth)acrylate, reactive It may be formed of a composition for a barrier layer comprising an unsaturated compound and an initiator.

The optical display device of the present invention may include the polarizing plate.

The present invention provides a polarizing plate comprising a barrier layer having excellent adhesion to a polarizer and having an antistatic effect.

The present invention has provided a polarizing plate comprising an optically transparent barrier layer.

The present invention provides a polarizing plate having good durability at high temperature and high humidity.

1 is a cross-sectional view of a polarizing plate according to an embodiment of the present invention.
2 is a cross-sectional view of a polarizing plate according to another embodiment of the present invention.

Hereinafter, embodiments of the present application will be described in more detail with reference to the accompanying drawings. However, the technology disclosed in this application is not limited to the embodiments described herein and may be embodied in other forms. However, the embodiments introduced herein are provided to ensure that the disclosed contents are thorough and complete and that the spirit of the present application is sufficiently conveyed to those skilled in the art. In order to clearly express the components of each device in the drawings, the sizes of the width and thickness of the components are slightly enlarged. The same reference numerals in the plurality of drawings refer to components that are substantially the same as each other.

In this specification, "upper" and "lower" are defined on the basis of the drawings, and "upper" can be changed to "lower" and "lower" to "upper" according to the viewpoint of the city, and "on" or What is referred to as "on" may include not only directly above, but also through other structures in the middle. On the other hand, what is referred to as "directly on" or "directly above" indicates that no other structure such as an intermediate is interposed.

“Moisture permeability” in this specification is a value measured at 40° C. and 90% relative humidity according to KS A1013 for the protective layer.

As used herein, "(meth)acrylic" means acrylic and/or methacrylic.

As used herein, “substituted” to “substituted” means at least one hydrogen atom of the functional group is an alkyl group of C1 to C10, a hydroxyl group, an amino group, a C6 to C10 aryl group, a halogen, a cyano group, or a C3 to C10 cyclo. It means substituted with an alkyl group or a C7 to C10 arylalkyl group.

Hereinafter, a polarizing plate according to an embodiment of the present invention will be described with reference to FIG. 1. 1 is a cross-sectional view of a polarizing plate according to an embodiment of the present invention.

Referring to FIG. 1, the polarizing plate 100 may include a polarizer 110, a protective layer 120, and a barrier layer 130. The polarizing plate 100 may include a protective layer 120, a polarizer 110, and a barrier layer 130 sequentially.

The polarization plate 100 may have a polarization degree change rate of Equation 1 below 3%, specifically 0% to 1%, more specifically 0% to 1%, and more specifically 0% to 0.5%. Within the above range, the polarizing plate has good durability at high temperature and high humidity and can be used in an optical display device.

<Equation 1>

Polarization change rate = ｜P ₀ -P ₅₀₀ ｜/P ₀ x 100

(In the formula 1, P ₀ is the initial polarization degree of the polarizing plate (unit:%),

P ₅₀₀ is the polarization degree of the polarizing plate (unit: %) after the polarizing plate was left at 60° C. and 95% relative humidity at constant temperature and humidity for 500 hours and at 25° C. for 1 hour. The polarizing plate 100 is P ₅₀₀ ≤ P ₀ in Equation 1 above, and P ₅₀₀ and P ₀ may be 90% or more, respectively, specifically 95.000% to 99.990%.

The polarizing plate 100 may have a light transmittance change rate of the following Equation 2 at a wavelength of 400 nm to 700 nm of 3.5% or less, specifically 0% to 3.5%: In the above range, the polarizing plate has good durability at high temperature or high temperature and high humidity, and is optical Can be used for display devices:

<Equation 2>

Light transmittance change rate = ｜T ₅₀₀ -T ₀ ｜/ T ₀ x 100

(In the formula 2, T ₀ is the initial light transmittance of the polarizing plate (unit:%),

T ₅₀₀ is the light transmittance of the polarizing plate (unit: %) after the polarizing plate was left for 500 hours at constant temperature and humidity at 60°C and 95% relative humidity. The polarizing plate 100 may be T ₅₀₀ ≤ T ₀ , and T ₅₀₀ and T ₀ may be 30% or more, specifically 30% to 50%, and more specifically 40% to 49%.

As such, although the polarizing plate 100 includes a protective layer 120 on one surface of the polarizer 110 and a barrier layer 130 on the other surface of the polarizer 110 without the protective layer 120, the barrier layer 130 ) By inhibiting water vapor and/or moisture infiltration to the other surface of the polarizer 110 at high temperature and high humidity, the rate of change in the degree of polarization in Equation 1 and the rate of change in light transmittance in Equation 2 can be lowered to make the polarizing plate thinner and high temperature or high temperature and high humidity Durability can be improved. The polarizing plate 100 may have a thickness of 250 μm or less, specifically 200 μm or less, and more specifically 150 μm or less. For example, the polarizing plate 100 may have a thickness of 50 μm to 115 μm. In the above range, it can be used in an optical display device.

The polarizing plate 100 may have an antistatic effect by including the barrier layer 130, and may increase adhesion between the polarizer 110 and the barrier layer 130. Through this, when the polarizing plate is used in the LCD panel, damage to the panel due to static electricity that may be added by the LCD panel can be prevented. In particular, the polarizing plate 100 can exhibit antistatic effect and barrier effect without deteriorating optical transparency by the barrier layer 130 alone, and the adhesion of the barrier layer 130 to the polarizer 110 is excellent, thereby significantly reducing the thickness of the polarizing plate. You can make it possible. An adhesive layer having an antistatic effect may be added to one side of the barrier layer to adhere to the LCD panel, but in this case, an antistatic effect may be lowered due to temperature or humidity, or foaming may occur. In addition, by preventing separation between the polarizer and the barrier layer at high temperature or high temperature and high humidity, the barrier effect and reliability can be improved.

Hereinafter, the polarizer 110, the protective layer 120, the barrier layer 130, the adhesive layer 140 according to the present embodiment, and a method of manufacturing the same will be described in detail.

Polarizer (110)

The polarizer 110 is formed between the protective layer 120 and the barrier layer 130 and may polarize external light incident on the polarizer 100.

The polarizer 110 may include a polarizer made of a polyvinyl alcohol-based resin film. Specifically, the polarizer may be a polyvinyl alcohol-based polarizer in which at least one of iodine and a dichroic dye is adsorbed on a polyvinyl alcohol-based resin film. In addition, the polarizer may be a polyene-based polarizer prepared by dehydrating a polyvinyl alcohol-based resin film.

The polyvinyl alcohol-based resin film may have a saponification degree of 85 mol% to 100 mol%, specifically 98 mol% to 100 mol%. The polyvinyl alcohol-based resin film may have a polymerization degree of 1,000 to 10,000, specifically 1,500 to 10,000. The polyvinyl alcohol-based resin film may have a thickness of 30 μm to 200 μm. In the saponification degree, polymerization degree and thickness range, a polarizer can be prepared.

Specifically, the polyvinyl alcohol-based polarizer adsorbs one or more of iodine and a dichroic dye onto a polyvinyl alcohol-based resin film, and the final stretching ratio is 2 to 8 times, specifically 3 to 6 times, MD (machine direction) uniaxial stretching. Can be manufactured. Stretching may include dry stretching, wet stretching, or a combination thereof. Specifically, the polyene-based polarizer can be prepared by adding an acid catalyst to a polyvinyl alcohol-based resin film, and then dehydrating and drying it. The acid catalyst may include an organic acid, an inorganic acid, or a mixture thereof, including an aromatic sulfonic acid such as toluene sulfonic acid including para-toluene sulfonic acid.

The polarizer 110 may have a thickness of 5 μm to 100 μm, specifically 5 μm to 50 μm. In the above range, it can be used for a polarizing plate. As thinning of the polarizing plate is required, the polarizer 110 may have a thickness of 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, or 12 μm to thin the polarizing plate.

Protective layer 120

The protective layer 120 is formed on one surface (light emission surface) of the polarizer 110 to protect the polarizer 110, and may be formed on one surface of the polarizer 110. The protective layer 120 may be formed on the light exit surface of the polarizer 110.

The protective layer 120 has a water permeability of 100 g/m ² ㆍday or less, specifically 1 g/m ² ㆍday to 70 g/m ² ㆍday, more specifically 5 g/m ² ㆍday to 60 g/m ² ㆍday Can be. By blocking the external moisture from penetrating the polarizer in the above range, durability of the polarizing plate at high temperature and high humidity can be increased, and durability of the polarizing plate at high temperature and high humidity can be further increased.

The protective layer 120 may have a thickness of 5 μm to 200 μm, specifically 10 μm to 150 μm, and more specifically 50 μm to 100 μm. In the above range, it can be used for a polarizing plate, and it can suppress warping of the polarizing plate together with the barrier layer.

The protective layer 120 may include a protective film or protective coating layer formed of an optically transparent resin.

In one embodiment, the protective film may be formed by melting and extruding the resin or a composition for a protective film containing the resin. If necessary, an additional stretching process may be added. The resin includes cyclic polyolefin-based resins, polycarbonate-based resins, polyethylene terephthalate (PET), etc., including cellulose ester-based resins including triacetyl cellulose, amorphous cyclic olefin polymers (COP), and the like. Polyacrylate-based resins, including polyester-based resins, polyethersulfone-based resins, polysulfone-based resins, polyamide-based resins, polyimide-based resins, acyclic-polyolefin-based resins, polymethylmethacrylate resins, and the like, It may include at least one of polyvinyl alcohol-based resin, polyvinyl chloride-based resin, polyvinylidene chloride-based resin. The protective film may be MD uniaxially stretched, TD uniaxially stretched, or MD/TD biaxially stretched film, and may have a retardation in a predetermined range. The composition for the protective film may further include a conventional additive in addition to the resin. Specifically, the additive may include an ultraviolet absorber, leveling agent, and antistatic agent. The ultraviolet absorber may include a conventional ultraviolet absorber that absorbs light having a wavelength of 200 nm to 400 nm. Specifically, the ultraviolet absorber may include at least one of a phenol-based, benzotriazole-based, salisilane-based, triazine-based, indole-based and oxamide-based.

In other embodiments, the protective layer can be a protective coating layer. The protective coating layer may increase good adhesion to the polarizer 110, transparency, mechanical strength, thermal stability, moisture barrier properties, and durability. The protective coating layer may be formed of an active energy ray-curable resin composition comprising an active energy ray-curable compound and a polymerization initiator.

The active energy ray-curable compound may include at least one of a cationically polymerizable curable compound, a radically polymerizable curable compound, a urethane resin, and a silicone resin. The cationic polymerizable curable compound may be an epoxy-based compound having at least one epoxy group in the molecule, or an oxetane-based compound having at least one oxetane ring in the molecule. The radically polymerizable curable compound may be a (meth)acrylic compound having at least one (meth)acryloyloxy group in the molecule.

The epoxy-based compound may be at least one of a hydrogenated epoxy-based compound, a chained aliphatic epoxy-based compound, a cyclic aliphatic epoxy-based compound, and an aromatic epoxy-based compound.

The radically polymerizable curable compound can realize a protective coating layer having excellent hardness and mechanical strength and high durability. The radically polymerizable curable compound can be obtained by reacting two or more (meth)acrylate monomers having at least one (meth)acryloyloxy group in a molecule and a functional group-containing compound, and at least two (meth)acryloyl oxides in the molecule. And (meth)acrylate oligomers having a timing.

As the (meth)acrylate monomer, a monofunctional (meth)acrylate monomer having one (meth)acryloyloxy group in the molecule, and a bifunctional (meth)acrylate having two (meth)acryloyloxy groups in the molecule It can be a monomer, and a polyfunctional (meth)acrylate monomer having three or more (meth)acryloyloxy groups in the molecule.

The (meth)acrylate oligomer may be a urethane (meth)acrylate oligomer, a polyester (meth)acrylate oligomer, an epoxy (meth)acrylate oligomer, or the like.

The polymerization initiator can cure the active energy ray-curable compound. The polymerization initiator may include at least one of a photocationic initiator and a photosensitizer.

Photocationic initiators can be used that are commonly known to those skilled in the art. Specifically, the photocationic initiator may use an onium salt containing cations and anions. Specifically, the cation is diphenyl iodonium, 4-methoxydiphenyl iodonium, bis(4-methylphenyl) iodonium, bis(4-tert-butylphenyl) iodonium, bis(dodecylphenyl) iodonium, (4 -Methylphenyl)[(4-(2-methylpropyl)phenyl)diaryl iodonium such as iodonium, triarylsulfonium such as triphenylsulfonium, diphenyl-4-thiophenoxyphenylsulfonium, bis[ And 4-(diphenylsulfonio)phenyl]sulfide. Specifically, the anion is phosphate (PF ₆ ^-) hexafluoropropane, borates (BF ₄ ^-) tetrafluoroborate, antimonate hexafluorophosphate (SbF ₆ ^-), are Senate hexafluorophosphate (AsF ₆ ^-), hexamethylene and the ^like-chloro antimonate (SbCl _6).

The photosensitizer can be used commonly known to those skilled in the art. Specifically, the photosensitizer may use one or more of thioxanthone-based, phosphorus-based, triazine-based, acetophenone-based, benzophenone-based, benzoin-based, and oxime-based.

The polymerization initiator may be included in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the active energy ray-curable compound. In the above range, the curing may be sufficient to have high mechanical strength and good adhesion to the polarizer.

The active energy ray-curable resin composition may further include conventional additives such as a silicone-based leveling agent, an ultraviolet absorber, and an antistatic agent. The additive may be included in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the active energy ray-curable compound.

Although not shown in FIG. 1, when the protective layer 120 is made of a protective film, it may be adhered to the polarizer 110 by an adhesive layer. The adhesive layer may be formed of a conventional polarizing plate adhesive known to those skilled in the art, for example, an aqueous adhesive (for example, polyvinyl alcohol), a photocurable adhesive (for example, epoxy, (meth)acrylate), and the like.

In addition, although not shown in FIG. 1, an additional function may be provided to the polarizing plate by further including a functional coating layer on one surface of the protective layer 120. Specifically, the functional coating layer may be one or more in a hard coating layer, an antireflection layer, an anti-fingerprint layer, an antistatic layer, a low reflection layer, a primer layer, etc., but is not limited thereto. The functional coating layer may have a thickness of 1 μm to 100 μm, specifically 1 μm to 50 μm, and more specifically 1 μm to 20 μm. In the above range, an additional function may be provided to the polarizing plate without affecting the protective film, and it may be used for the polarizing plate.

Barrier layer (130)

The barrier layer 130 is formed on the other surface (light incidence surface) of the polarizer 110 to protect the polarizer 110 from the opposite side of the protective layer 120 from the polarizer 110 and external moisture to the polarizer ( By blocking penetration into 110), durability of the polarizing plate 100 at high temperature and high humidity can be increased. The barrier layer 130 may be formed on the light incident surface of the polarizer 110.

Since the barrier layer 130 has high adhesion to the polarizer 110, the barrier layer 130 is formed directly on the polarizer 110 and directly formed on the polarizer 110 without an adhesive layer, thereby realizing a thinning effect of the polarizer 100. The'directly formed' means that any layer including an adhesive layer, an adhesive layer, etc. is not interposed between the polarizer 110 and the barrier layer 130.

The barrier layer 130 may have a thickness of 20 μm or less, specifically 1 μm to 15 μm, and more specifically 2 μm to 12 μm. In the above range, it can be used for a polarizing plate, it has an appropriate thickness ratio for the protective layer and the adhesive layer, it can suppress the warpage of the polarizing plate, increase the barrier properties to prevent cracking of the polarizer.

The barrier layer 130 is provided on one surface of the polarizer and is directly attached to the other surface of the barrier layer by being adhered to the liquid crystal display panel by the above-described adhesive layer, thereby fixing the polarizing plate 100 to the liquid crystal display panel.

The barrier layer 130 may have a light transmittance of 90% or more at a wavelength of 300 nm to 700 nm.

The barrier layer 130 may be formed of a composition for a barrier layer. The composition for the barrier layer is a photocurable composition, and can be cured with active energy rays including ultraviolet rays, electron beams, and the like. Hereinafter, the composition for the barrier layer will be described in detail.

The composition for the barrier layer may include a conductive polymer, a cellulose ester, a hydroxyl group-containing (meth)acrylate, a reactive unsaturated compound, and an initiator. Therefore, there is a static dissipative effect, high adhesion to a polarizer, optically transparent, and a barrier effect.

The conductive polymer may provide an antistatic function to the barrier layer. Therefore, the commercial logarithm of the surface resistance measured for the polarizing plate may be 10 Ω/□ or less, for example, 9 Ω/□ or less. In the above range, the barrier layer has an antistatic function, thereby preventing panel damage due to static electricity that may be added by the LCD panel when the polarizing plate is used in the LCD panel.

The conductive polymer may include conventional conductive polymers known to those skilled in the art. For example, conductive polymers include polyacetylene, poly(p-phenylene), polythiophene, poly(3,4-ethylenedioxythiophene), polypyrrole, poly(p-phenylene sulfide), poly(p-phenyl) Renvinylene), poly(thienylene vinylene), and polyaniline.

The conductive polymer may be included in the composition for the barrier layer as the conductive polymer itself, or may be introduced into the composition for the barrier layer as a dispersion containing the conductive polymer.

In the present invention, the conductive polymer may mean a conductive polymer doped with dopant. For example, the conductive polymer can be doped with an aqueous dopant, for example polystyrenesulfonate. For example, the conductive polymer can include poly(3,4-ethylenedioxythiophene) doped with polystyrenesulfonate.

The conductive polymer may include 0.001 part to 20 parts by weight, specifically 0.1 part to 10 parts by weight, of 100 parts by weight of the conductive polymer, cellulose ester, hydroxyl group-containing (meth)acrylate, reactive unsaturated compound, and initiator. Within this range, it is possible to simultaneously satisfy the optical and antistatic properties of the barrier layer.

The cellulose ester can increase the adhesion of the barrier layer to the polarizer together with the hydroxyl group-containing (meth)acrylate, and simultaneously reduce the light transmittance change rate and the polarization change rate of the polarizing plate and improve the adhesion. When only cellulose ester is included, optical properties may deteriorate under high temperature and high humidity. If only the hydroxyl group-containing (meth)acrylate is included, adhesion may be deteriorated.

In one embodiment, the polarizing plate may have fewer than 5 separated specimens, for example 0, when evaluated by cross cut. In the above range, the adhesion to the polarizer is excellent and can be used in a display device. The "cross cut" can be measured by the method described below.

Cellulose esters may include esters in which part of the -OH group of cellulose or -OH group of -CH ₂ -OH is modified with one or more -O-(C=O)-R. At this time, R may be a C1 to C10 alkyl group, for example, a methyl group, an ethyl group, or a butyl group. Cellulose ester binders may also contain homogeneous or heterogeneous -O-(C=O)-R. Specifically, the cellulose ester may include one or more of cellulose acetate butyrate, cellulose acetate propionate, cellulose acetate, and cellulose propionate.

The cellulose ester may be included in 1 part by weight to 50 parts by weight, specifically 20 parts by weight to 50 parts by weight, of 100 parts by weight of the conductive polymer, cellulose ester, hydroxyl group-containing (meth)acrylate, reactive unsaturated compound, and initiator. Within this range, adhesion of the barrier layer to the polarizer can be increased.

The hydroxyl group-containing (meth)acrylate increases the adhesion of the barrier layer to the polarizer together with the cellulose ester, and may have an effect of improving durability.

The hydroxyl group-containing (meth)acrylate is 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylic Rate, 3-hydroxypropyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 1,4-cyclohexanedimethanol mono (meth)acrylate, 1-chloro-2-hydroxypropyl (meth) )Acrylate, diethylene glycol mono(meth)acrylate, 1,6-hexanediol mono(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, neopentyl glycol Cole mono(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolethane di(meth)acrylate, 2-hydroxy-3-phenyloxypropyl (meth)acrylate, 4-hydroxycyclopentyl (Meth)acrylate, 4-hydroxycyclohexyl (meth)acrylate, and cyclohexanedimethanol mono(meth)acrylate. Preferably, the hydroxyl group-containing (meth)acrylate may be a monofunctional (meth)acrylate.

The hydroxyl group-containing (meth)acrylate is contained in 1 part by weight to 15 parts by weight, 5 parts by weight to 10 parts by weight of 100 parts by weight of the total amount of the conductive polymer, cellulose ester, hydroxyl group-containing (meth)acrylate, reactive unsaturated compound, and initiator. Can. In the above range, it may increase the adhesion of the barrier layer to the polarizer and improve durability.

The reactive unsaturated compound can be a non-hydroxy group reactive unsaturated compound that does not contain a hydroxyl group. For example, the homopolymer has a glass transition temperature (Tg) of 50°C or higher and includes a mixture of a monofunctional or bifunctional (meth)acrylate, a compound represented by Formula 1, and a trifunctional or higher (meth)acrylate. can do.

The reactive unsaturated compound may be included in 5 to 60 parts by weight, preferably 15 to 50 parts by weight, of 100 parts by weight of the total amount of the conductive polymer, cellulose ester, hydroxyl group-containing (meth)acrylate, reactive unsaturated compound, and initiator. have. In the above range, there may be a durability improvement effect.

The (meth)acrylate having a glass transition temperature (Tg) of 50° C. or higher of the homopolymer can increase the mechanical strength and modulus of the barrier layer to increase durability and moisture resistance at high temperatures and high humidity of the polarizing plate. Specifically, the (meth)acrylate having a glass transition temperature (Tg) of 50°C or higher of the homopolymer has a glass transition temperature of 60°C or higher of the homopolymer, for example, 80°C or higher, 60°C to 200°C, 60°C to 150 And (meth)acrylate, which is ℃. In the glass transition temperature range, crack resistance under thermal shock due to a modulus rise of the barrier layer may be increased. The "glass transition temperature of the homopolymer" can be measured by a conventional method known to those skilled in the art.

The (meth)acrylate having a glass transition temperature (Tg) of the homopolymer of 50°C or higher may include at least one of a monofunctional (meth)acrylate and a bifunctional (meth)acrylate. These may be included in the barrier layer composition alone or in combination of two or more. The monofunctional (meth)acrylate may be included alone or in a mixture of two or more kinds in a composition for a barrier layer. The bifunctional (meth)acrylate may be included in the barrier layer composition alone or in combination of two or more.

Specifically, the (meth)acrylate having a glass transition temperature (Tg) of 50°C or higher of the homopolymer is dimethylol tricyclodecane di(meth)acrylate, tris(2-hydroxyethyl)isocyanurate di(meth). Acrylate, 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene, hydroxypivalaldehyde modified trimethylolpropane di(meth)acrylate, hexanediol Di(meth)acrylate, nonanediol di(meth)acrylate, neopentyl glycol propoxylate di(meth)acrylate, neopentyl glycol di(meth)acrylate, tri(propylene glycol) di(meth)acrylate And poly(alkylene glycol) di(meth)acrylates including dipropylene glycol di(meth)acrylate and the like. The'alkylene' may be alkylene having 2 to 5 carbon atoms. More specifically, the (meth)acrylate having a glass transition temperature (Tg) of a homopolymer of 50°C or higher includes an isocyanurate group comprising tris(2-hydroxyethyl)isocyanurate di(meth)acrylate. By including the (meth)acrylate having, it is possible to further increase the durability of the polarizing plate at high temperature and high humidity.

The (meth)acrylate having a glass transition temperature (Tg) of 50°C or higher of the homopolymer is 1 part by weight to 50 of 100 parts by weight of the total amount of the conductive polymer, cellulose ester, hydroxyl group-containing (meth)acrylate, reactive unsaturated compound, and initiator. It may be included in parts by weight, specifically 10 parts by weight to 40 parts by weight. Within the above range, the rate of change in polarization degree and the rate of change in light transmittance at a high temperature or high temperature and high humidity of the polarizing plate may be lowered.

The compound represented by the following Chemical Formula 1 prevents water vapor and/or water from penetrating the barrier layer with (meth)acrylate having a glass transition temperature of 50°C or higher of the homopolymer, thereby improving water resistance and moisture resistance at high temperatures and/or high humidity of the polarizing plate. It is possible to lower the rate of change of the polarization degree of the polarizing plate by increasing and preventing discoloration of the polarizer by water and/or water. In particular, the vinyl ester of Formula 1 (a compound in which R ₃ is a vinyl group) is not deteriorated by an active energy ray, so that discoloration of the polarizing plate can be suppressed.

<Formula 1>

(In Formula 1, R ₁ and R ₂ are each independently an unsubstituted or substituted C1 to C20 alkyl group, and R ₃ is hydrogen or a vinyl group). Compounds of Formula 1 may be included alone or in combination of two or more.

Specifically, in Formula 1, R ₁ and R ₂ may each independently be a methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group or octyl group. Specifically, in Formula 1, R ₁ and R ₂ may be an alkyl group in which the total carbon number of R ₁ and R ₂ is 6 to 8, specifically 6, 7 or 8. Specifically, in Formula 1, R ₃ becomes a vinyl group, and the compound of Formula 1 may be a vinyl ester. At this time, the polarization degree of the polarizing plate may be lowered in the content rate and the moisture content change rate.

The compound of Formula 1 may include one or more of commercially available products VeoVa-9, VeoVa-10, VeoVa-11 (above, Momentive Co.), and versatic acid (Hexicon Co.). In particular, VeoVa-10 has excellent adhesion, water resistance, and water repellency, and does not deteriorate due to UV, and thus has strong discoloration characteristics.

The compound of Formula 1 may be included in an amount of 0.1 to 10 parts by weight, specifically 0.5 to 5 parts by weight, of 100 parts by weight of the total amount of the conductive polymer, cellulose ester, hydroxyl group-containing (meth)acrylate, reactive unsaturated compound, and initiator. have. In the above range, the water resistance and moisture resistance at high temperature and/or high humidity of the polarizing plate may be increased, and the polarization degree change rate of the polarizing plate may be reduced by preventing discoloration of the polarizer by water vapor and/or water.

The trifunctional or higher (meth)acrylate can improve the crosslinking density of the barrier layer, thereby increasing the cohesive energy of the barrier layer and increasing the reliability. Trifunctional or higher (meth)acrylates can be cured in response to radicals initiated by light energy. Specifically, the trifunctional or higher (meth)acrylate may be a trifunctional to 6 functional polyfunctional (meth)acrylate, more specifically a trifunctional, tetrafunctional, 5 functional, or 6 functional (meth)acrylate. have.

Specifically, the trifunctional or higher (meth)acrylate is unsubstituted, glycerin tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, ditrimethylolpropanetetra (Meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipenta And polyfunctional (meth)acrylates of unsubstituted trifunctional or higher aliphatic polyols such as erythritol hexa(meth)acrylate. In addition, trifunctional (meth)acrylates of trifunctional or higher functional groups include polyfunctional (meth)acrylates of halogen-substituted aliphatic polyols, tri(meth)acrylates of alkylene oxide adducts, and trimethylolpropane alkylene oxide adducts ( Meth)acrylate, 1,1,1-tris[(meth)acryloyloxyethoxyethoxy]propane, tris(hydroxyethyl)isocyanurate tri(meth)acrylate, 6-functional polyester acrylic Rate (PS-610, Miwon Corporation).

The trifunctional or higher (meth)acrylate may be included in the barrier layer composition alone or in combination of two or more.

The trifunctional or higher (meth)acrylate is 0.1 parts by weight to 10 parts by weight, specifically 0.5 parts by weight to 5 parts by weight, among 100 parts by weight of the conductive polymer, cellulose ester, hydroxyl group-containing (meth)acrylate, reactive unsaturated compound, and initiator. It may be included in parts by weight. In the above range, durability improvement effect may be obtained under severe conditions.

The initiator can cure the reactive unsaturated compound. The initiator may include at least one of a photoradical initiator and a photocationic initiator. The initiator may be used alone or in combination of two or more.

Photoradical initiators can be used that are commonly known to those skilled in the art. Specifically, the photo-radical initiator may use one or more of thioxanthone-based, phosphorus-based, triazine-based, acetophenone-based, benzophenone-based, benzoin-based, and oxime-based. Specifically, the photo-radical initiator is phosphorus-based, for example, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)(2,4,4-trimethylpentyl)phosphine oxide, etc. Can be used.

Photocationic initiators can be used that are commonly known to those skilled in the art. Specifically, the photocationic initiator may use an onium salt containing cations and anions. Specifically, the cation is diphenyl iodonium, 4-methoxydiphenyl iodonium, bis(4-methylphenyl) iodonium, bis(4-tert-butylphenyl) iodonium, bis(dodecylphenyl) iodonium, (4 -Methylphenyl)[(4-(2-methylpropyl)phenyl)diaryl iodonium such as iodonium, triarylsulfonium such as triphenylsulfonium, diphenyl-4-thiophenoxyphenylsulfonium, bis[ And 4-(diphenylsulfonio)phenyl]sulfide. Specifically, the anion is phosphate (PF ₆ ^-) hexafluoropropane, borates (BF ₄ ^-) tetrafluoroborate, antimonate hexafluorophosphate (SbF ₆ ^-), are Senate hexafluorophosphate (AsF ₆ ^-), hexamethylene and the ^like-chloro antimonate (SbCl _6).

The initiator may be included in 0.1 parts by weight to 15 parts by weight, specifically 1 part by weight to 10 parts by weight, of 100 parts by weight of the conductive polymer, cellulose ester, hydroxyl group-containing (meth)acrylate, reactive unsaturated compound, and initiator. In the above range, the curable component can be sufficiently cured, and a residual amount of initiator remains to prevent the transparency of the barrier layer from being lowered.

The barrier layer composition may be a solvent-free composition that does not contain a solvent, but may further include a solvent to facilitate coating, coating, or processability. Solvents may include, but are not limited to, methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, and the like.

The barrier layer composition may further include an additive. Additives can provide additional functionality to the barrier layer. Specifically, the additive may include one or more of UV absorbers, reaction inhibitors, adhesion improvers, thixotropic agents, conductivity imparting agents, dye modifiers, stabilizers, antistatic agents, antioxidants, and leveling agents, but is not limited thereto. Does not work.

The barrier layer can be prepared by coating and curing the composition for the barrier layer on one surface of the polarizer. The composition for the barrier layer may be applied by die coating, gravure coating, or the like. Curing can include irradiation with active energy ray in the UV specifically, 100mW / cm ² to ^{2,000mW / cm 2, 100mJ / cm} 2 to 2,000mJ / cm ^2.

Hereinafter, a polarizing plate according to another embodiment of the present invention will be described with reference to FIG. 2. 2 is a cross-sectional view of a polarizing plate according to another embodiment of the present invention.

Referring to FIG. 2, the polarizing plate 200 may include a polarizer 110, a protective layer 120, a barrier layer 130, and an adhesive layer 140. The polarizing plate 200 is formed with an adhesive layer 140 on the lower surface of the barrier layer 130, so that a polarizing plate and a panel for an optical display device such as a liquid crystal panel can be adhered. It is substantially the same as the polarizing plate according to an embodiment of the present invention, except that the adhesive layer is further formed. Therefore, hereinafter, only the adhesive layer will be described.

The adhesive layer 140 is formed on the lower surface of the barrier layer to adhere the polarizing plate to a panel or the like.

The adhesive layer 140 may have a thickness of 5 μm to 40 μm, specifically 10 μm to 30 μm. In the above range, it can be used for a polarizing plate.

The adhesive layer 140 may be formed of a composition for an adhesive layer comprising a (meth)acrylic copolymer and a crosslinking agent. Hereinafter, the composition for an adhesive layer will be described.

The composition for the adhesive layer may include a (meth)acrylic copolymer and a crosslinking agent of a monomer mixture containing a (meth)acrylic monomer having an alkyl group and a (meth)acrylic monomer having a hydroxyl group.

The (meth)acrylic monomer having an alkyl group may include (meth)acrylic acid ester having an unsubstituted C1 to C20 alkyl group. Specifically, the (meth)acrylic monomer having an alkyl group is ethyl (meth)acrylate, propyl (meth)acrylate, N-butyl (meth)acrylate, pentyl (meth)acrylate, 2-ethylhexyl (meth)acrylic Rate. These may be included alone or in combination of two or more.

The (meth)acrylic monomer having a hydroxyl group may include a (meth)acrylic acid ester having an alkyl group of C1 to C20 having one or more hydroxyl groups. Specifically, the (meth)acrylic monomer having a hydroxyl group may include at least one of 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Can. These may be included alone or in combination of two or more.

The monomer mixture may include 90 parts by weight to 99 parts by weight of a (meth)acrylic monomer having an alkyl group based on a solid content, and 1 part by weight to 10 parts by weight of a (meth)acrylic monomer having a hydroxyl group. In the above range, adhesion to the barrier layer and the liquid crystal glass may be high.

The (meth)acrylic copolymer can be prepared by a conventional method. Specifically, an initiator may be added to the monomer mixture and reacted at 50°C to 100°C. As the initiator, 2,2'-azobisisobutyronitrile (AIBN) or the like can be used, but is not limited thereto. The initiator may be included in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the monomer mixture. In the above range, the production yield of the (meth)acrylic copolymer can be increased.

The crosslinking agent cures the (meth)acrylic copolymer, and may include a common isocyanate crosslinking agent. Specifically, the crosslinking agent may include at least one of hexamethylene diisocyanate, tolylene diisocyanate, xylene diisocyanate, isophorone diisocyanate, naphthalene diisocyanate, and trimethylolpropane modified tolylene diisocyanate adducts. The crosslinking agent may be included in 0.1 parts by weight to 1 part by weight based on 100 parts by weight of the (meth)acrylic copolymer. In the above range, the pressure-sensitive adhesive composition can be cross-linked well to achieve an adhesion effect.

The pressure-sensitive adhesive composition may further include at least one of a silane coupling agent and a crosslinking catalyst.

The optical display device according to an embodiment of the present invention may include a polarizing plate according to embodiments of the present invention. The optical display device may be a liquid crystal display device or an organic light emitting display device, but is not limited thereto.

Hereinafter, the configuration and operation of the present invention through embodiments of the present invention will be described in more detail. However, the following examples are intended to help the understanding of the present invention, and the scope of the present invention is not limited to the following examples.

Hereinafter, specific specifications of the components used in Examples and Comparative Examples are as follows.

① Conductive polymer: Polyethylene dioxythiophene doped with polystyrene sulfonic acid, (Batron PH, Starck)

② Cellulose ester: Cellulose acetate butyrate: CAB381, Eastman

③ hydroxyl group-containing (meth)acrylate: 2-hydroxyethyl methacrylate: (HEMA, Daejung)

④ Among the reactive unsaturated compounds, the homopolymer has a glass transition temperature of 50°C or higher (meth)acrylate: tris(2-hydroxyethyl)isocyanurate diacrylate (Tg:131°C of homopolymer, M-2370, Miwon superior)

⑤ Compound of formula 1 among reactive unsaturated compounds: VeoVa-10 (Tg:-3℃ of homopolymer, Momentive)

⑥ Three or more functional (meth)acrylates among reactive unsaturated compounds: pentaerythritol tetraacrylate (PETA, Miwon Corporation)

⑦ Initiator: Takeover initiator: Darocure TPO, Ciba

Example One

(1) polarizer manufacturing

A polyvinyl alcohol-based film (degree of saponification: 99.5 mol%, degree of polymerization: 2000, thickness: 80 µm) was immersed in a 0.3% aqueous solution of iodine for dyeing. It was uniaxially stretched at a draw ratio of 5.0. The stretched polyvinyl alcohol-based film was immersed in a 3% aqueous boric acid solution and a 2% aqueous potassium iodide solution to correct color. It was dried at 50° C. for 4 minutes to prepare a polarizer (thickness: 23 μm).

(2) Preparation of barrier layer composition

Tris(2-hydroxyethyl)isocyanurate diacrylate 33 parts by weight, VeoVa-10 4 parts by weight and pentaerythritol tetraacrylate 4 parts by weight were mixed. The obtained mixture was mixed with 6 parts by weight of 2-hydroxyethyl methacrylate, 6 parts by weight of conductive polymer, 41 parts by weight of cellulose acetate butyrate, and 6 parts by weight of initiator, and mixed for 10 minutes to prepare a composition for a barrier layer. Table 1 (unit: parts by weight) shows the content of each component in 100 parts by weight of the barrier layer composition.

(3) Polarizing plate manufacturing

The polarizing plate was prepared at 22°C to 25°C and relative humidity of 20% to 60%. A composition for an aqueous adhesive layer was applied to one surface of the protective layer and laminated with one surface of the polarizer. The composition for the barrier layer was applied to the other side of the polarizer and irradiated with ultraviolet rays at 400 mW/cm ² and 1000 mJ/cm ² with a metal halide lamp, so that the barrier layer (thickness: 5 μm), polarizer (thickness: 23 μm), and the protective layer (TAC film, thickness: 80㎛) was prepared in order to form a polarizing plate.

Example 2 to Example 3 and Comparative example 1 to Comparative example 4

In Example 1, a polarizing plate was manufactured in the same manner, except that the contents of each component were changed as shown in Table 1 below.

① ② ③ ④ ⑤ ⑥ ⑦ Example 1 6 41 6 33 4 4 6 Example 2 4 48 10 27 3 3 5 Example 3 5 37 5 36 5 5 7 Comparative Example 1 2 77 0 14 2 2 3 Comparative Example 2 6 0 45 35 4 4 6 Comparative Example 3 32 34 34 0 0 0 0 Comparative Example 4 0 0 0 67 10 10 13

The physical properties of Table 2 below were evaluated for the polarizing plates of Examples and Comparative Examples.

(1) Common logarithmic value of surface resistance: An adhesive layer (thickness: 20 µm, acrylic, no conductive polymer) was laminated on one surface of the barrier layer in the polarizing plates of Examples and Comparative Examples. Using the SIMCO ST-3 device on the adhesive layer side of the prepared polarizing plate, surface resistance was measured at 23° C. and relative humidity of 55% to obtain a commercial logarithm of the surface resistance (unit: Ω/□).

(2) Adhesion (cross-cut, cross-cut): A square specimen was prepared by cutting the polarizing plates of Examples and Comparative Examples into length x width (25 mm x 25 mm). The specimen was drawn in 10 rows in the horizontal direction and 10 rows in the vertical direction to obtain a total of 100 fractions. A 3M acrylic scotch tape was applied to one side of the barrier layer and teared at a time to obtain the number of torn off fractions. The lower the number of torn off fractions, the better the adhesion of the barrier layer to the polarizer.

(3) Polarization rate of change: The polarization plates of Examples and Comparative Examples were cut to length x width (25 mm x 25 mm) and laminated to the center of the glass plate, and then, using V-7170 (Jasco), the initial polarization degree of the polarizer at a wavelength of 400 nm to 700 nm ( P ₀ ) was measured. The polarizing plate was left at 60° C. and 95% relative humidity for 500 hours, and after standing at 25° C. for 1 hour, the polarization degree (P ₅₀₀ ) of the polarizing plate was measured at a wavelength of 400 nm to 700 nm using V-7170 (Jasco). Did. The rate of change in polarization was calculated according to Equation 1 above.

(4) Light transmittance change rate: For the polarizing plates of Examples and Comparative Examples, UV-530 (Jasco) was used to measure the initial light transmittance (T ₀ ) of the polarizing plates at a wavelength of 400 nm to 700 nm. The polarizing plate was left at 60° C. and 95% relative humidity for 500 hours, and after standing at 25° C. for 1 hour, UV-530 (Jasco) was used to measure the light transmittance (T ₅₀₀ ) of the polarizing plate at a wavelength of 400 nm to 700 nm. Did. The change rate of light transmittance was calculated according to Equation 2 above.

(5) Light transmittance: The barrier layer compositions of Examples and Comparative Examples were applied to Glass with a thickness of 5 μm and irradiated with ultraviolet rays at 400 mW/cm ² and 1000 mJ/cm ² with a metal halide lamp to form a barrier layer. The light transmittance of the barrier layer was measured using UV-530 (Jasco) at a wavelength of 400 nm to 700 nm.

(6) Durability: Examples and comparative examples were prepared by cutting the polarizing plates in length x width (400 mm x 200 mm) and attaching them so that the absorption axes of the polarizers were perpendicular to each other on both sides of the glass plate. The prepared specimens were left at 60°C and 95% relative humidity for 500 hours, and then taken out at room temperature for evaluation.

○: No change in appearance such as cracks in the polarizer

△: Appearance defect such as crack/bubble on the polarizer is less than 300㎛

×: Appearance defects such as cracks/bubbles on the polarizer 300 µm or more

Example Comparative example One 2 3 One 2 3 4 Common logarithmic value of surface resistance
(Ω/□) 7.8 8.2 8.8 8.3 8.3 7.9 No measurement* Adhesion
(dog) 0 0 0 5 10 25 37 Polarization change rate
(%) 0.3 0.2 0.3 0.2 0.5 2.0 3.0 Light transmittance change rate
(%) 2.5 3.4 2.7 14.8 3.7 11.2 11.2 Light transmittance
(%) 91.7 92.5 92.8 92.5 92.5 92.5 92.5 durability ○ ○ ○ × × × ×

*Not measurable: The surface resistance is too high to measure.

As shown in Table 2, the polarizing plate according to the present embodiment has excellent adhesion to a polarizer and a low logarithmic value of surface resistance, thereby providing excellent antistatic effect and excellent durability at high temperature and high humidity.

On the other hand, Comparative Example 1 without hydroxyl group-containing (meth)acrylate had poor adhesion to a polarizer and durability. Comparative Example 2 without cellulose ester had poor adhesion to polarizers and durability. Comparative Example 3 lacking a reactive unsaturated compound had poor adhesion to a polarizer and durability, and a high rate of change in light transmittance. Comparative Example 4 made of only a reactive unsaturated compound had no antistatic effect, poor adhesion to a polarizer, and poor durability, and a high rate of change in light transmittance.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be considered to be included in the scope of the present invention.

Claims (12)

The protective layer, the polarizer, and the barrier layer are sequentially formed polarizing plates,
The barrier layer is a polarizing plate, which is formed of a composition for a barrier layer comprising a conductive polymer, a cellulose ester, a hydroxyl group-containing (meth)acrylate, a reactive unsaturated compound, and an initiator,
The reactive unsaturated compound includes a mixture of a monofunctional or bifunctional (meth)acrylate having a glass transition temperature (Tg) of a homopolymer of 50°C or higher, a compound represented by the following Chemical Formula 1, and a trifunctional or higher (meth)acrylate. Polarizing plate:
<Formula 1>

(In Formula 1, R ₁ and R ₂ are each independently an unsubstituted or substituted C1 to C20 alkyl group, and R ₃ is hydrogen or a vinyl group).
The polarizing plate of claim 1, wherein the barrier layer is formed directly on the polarizer.
The method according to claim 1, wherein the conductive polymer is doped with dopant, polyacetylene, poly(p-phenylene), polythiophene, poly(3,4-ethylenedioxythiophene), polypyrrole, poly(p-phenylene) Sulfide), poly(p-phenylenevinylene), poly(thienylene vinylene), or polyaniline.
The polarizing plate of claim 1, wherein the cellulose ester comprises at least one of cellulose acetate butyrate, cellulose acetate propionate, cellulose acetate, and cellulose propionate.
delete The polarizing plate according to claim 1, wherein the monofunctional or bifunctional (meth)acrylate having a glass transition temperature (Tg) of the homopolymer of 50° C. or higher includes (meth)acrylate having an isocyanurate group.
The method of claim 1, wherein the conductive polymer, the cellulose ester, the hydroxyl group-containing (meth) acrylate, the reactive unsaturated compound, and the total of 100 parts by weight of the initiator,
0.001 part by weight to 20 parts by weight of the conductive polymer,
1 to 50 parts by weight of the cellulose ester,
1 to 15 parts by weight of the hydroxyl group-containing (meth)acrylate,
5 to 60 parts by weight of the reactive unsaturated compound, and
A polarizing plate comprising 0.1 parts by weight to 15 parts by weight of the initiator.
The polarizing plate of claim 1, wherein an adhesive layer is further formed on the other surface of the barrier layer.
The polarizing plate of claim 1, wherein the barrier layer has a light transmittance of 90% or more at a wavelength of 300 nm to 700 nm.
The polarizing plate according to claim 1, wherein the polarizing plate has a rate of change in polarization of Formula 1 of 3% or less:
<Equation 1>
Polarization change rate = ｜P ₀ -P ₅₀₀ ｜/P ₀ x 100
(In the formula 1, P ₀ is the initial polarization degree of the polarizing plate (unit:%),
P ₅₀₀ is the polarization of the polarizing plate (unit: %) after leaving the polarizing plate at 60°C and 95% relative humidity for 500 hours at constant temperature and humidity for 1 hour at 25°C.
The polarizing plate of claim 1, wherein the polarizing plate has a light transmittance change rate of Formula 2 below 3.5% at a wavelength of 400 nm to 700 nm:
<Equation 2>
Light transmittance change rate = ｜T ₅₀₀ -T ₀ ｜/ T ₀ x 100
(In the formula 2, T ₀ is the initial light transmittance of the polarizing plate (unit:%),
T ₅₀₀ is the light transmittance of the polarizing plate (unit: %) after the polarizing plate was left for 500 hours at constant temperature and humidity at 60°C and 95% relative humidity.
An optical display device comprising the polarizing plate of any one of claims 1 to 4 and 6 to 11.

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