WO2016159645A1 - Polarizing plate and optical display device including same - Google Patents

Abstract

Provided are: a polarizing plate that includes a polarizer, an adhesive layer formed on the top surface of the polarizer, a protective layer formed on the top surface of the adhesive layer and having a water permeability of about 30g/m2· 24hr or less, and a barrier layer formed on the bottom surface of the polarizer, wherein the polarizing plate has a rate of change of polarization represented by Formula 1 of about 3% or less and a rate of change in water content represented by Formula 2 of about 10% or less; and an optical display device including the polarizing plate.

Description

Polarizing plate and optical display device including the same

The present invention relates to a polarizing plate and an optical display device including the same.

The liquid crystal display device includes a liquid crystal panel and polarizing plates formed on both surfaces of the liquid crystal panel, respectively. The polarizing plate includes a polarizer and a protective film formed on both surfaces of the polarizer, respectively. In recent years, a polarizing plate has been 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 vulnerable to moisture and more vulnerable to moisture at high temperatures. At high temperature and high humidity, the polarizer may be less durable due to external moisture penetration, and may be less cracked of the polarizer. Polarizers with high durability at high temperatures have been developed. However, high temperature / high humidity are harsher conditions than high temperature and polarizers are vulnerable to moisture. Therefore, even in a polarizing plate having high durability at high temperature, there is a limit in increasing durability even at high temperature / high humidity.

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

The problem to be solved by the present invention is to provide a polarizing plate with good durability at high temperature and high humidity.

Another object of the present invention is to provide a polarizing plate including a barrier layer that is excellent in adhesion to the polarizer and increases the crack resistance of the polarizer.

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

The polarizing plate of the present invention includes a polarizer, an adhesive layer formed on the upper surface of the polarizer, a protective layer formed on the upper surface of the adhesive layer and having a water transmittance of about 30 g / m ² ㆍ 24hr or less, and a barrier layer formed on the lower surface of the polarizer. In addition, the polarizing plate may have a polarization degree change rate of about 3% or less in Equation 1 below, and a water content change rate of about 2% or less in Equation 2 below:

<Equation 1>

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

(In Formula 1, P ₀ and P ₅₀₀ are as defined in the following detailed description of the invention),

<Equation 2>

Moisture content change rate = ｜ W ₅₀₀ -W ₀ ｜ / W ₀ x 100

(In Formula 2, W ₀ and W ₅₀₀ are as defined in the following detailed description of the invention).

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

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

The present invention provides a polarizing plate including a barrier layer which is excellent in adhesion to the polarizer and increases the crack resistance of the polarizer.

The present invention provides a polarizing plate having good water resistance and cutting property 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 polarizer according to another embodiment of the present invention.

3 is a cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, it will be described embodiments of the present application in more detail. However, the technology disclosed in the present application is not limited to the embodiments described herein and may be embodied in other forms. It is merely to be understood that the embodiments introduced herein are provided so that the disclosure can be made thorough and complete, and that the spirit of the present application can be fully conveyed to those skilled in the art. In the drawings, the width, thickness, and the like of the components are enlarged in order to clearly express the components of each device. Like reference numerals refer to like elements throughout the drawings.

In the present specification, "upper" and "lower" are defined based on the drawings, and according to a viewpoint, "upper" may be changed to "lower" and "lower" to "upper", and "on" or What is referred to as “on” may include not only the above but also intervening other structures in the middle. On the other hand, what is referred to as "directly on" or "directly on" means not intervening in other structures such as intermediates.

“Moisture permeability” herein is a value measured at 40 ° C. and 90% relative humidity in accordance with KS A1013 for the protective layer.

As used herein, "modulus of barrier layer" is a value measured for a barrier layer specimen (which may be storage modulus or elastic modulus). The barrier layer specimen was coated with a barrier layer composition on a release film (eg, polyethylene terephthalate film) with a thickness of 50 μm and irradiated with UV under conditions of 400 mW / cm ² and 1000 mJ / cm ^{2 with} a metal halide lamp to remove the release film. It is manufactured by. The barrier layer specimen may have a width x length x thickness (10 mm x 100 mm x 50 μm). The modulus of the barrier layer is fixed to the DMA Q800 (TA Instrument Co., Ltd.), measured in the tension mode, temperature increase rate 5 ℃ / min, temperature range 0 ℃ to 100 ℃, frequency 1 Hz, strain 5% in an analysis mode, 25 The value in ° C was made modulus.

As used herein, "modulus of an adhesive layer" is a storage modulus. The modulus of the pressure-sensitive adhesive layer is coated on a release film (for example, polyethylene terephthalate film) and cured for 48 hours at 35 ° C. and 45% relative humidity to prepare a pressure-sensitive adhesive film having a thickness of 25 μm. A 0.8 mm thick specimen was prepared by overlapping a plurality of adhesive films, and the prepared specimen was subjected to a temperature sweep test (strain 5%, normal force 100 N) at 23 ° C. and 1 Hz using ARES (Advanced Rheometric Expansion System, TA instrument). Measured at

As used herein, "(meth) acryl" refers to acrylic and / or methacryl.

In this specification, "unsubstituted or substituted" means "substituted" means that at least one hydrogen atom of the functional group is a C1 to C10 alkyl group, a hydroxyl group, an amino group, a C6 to C10 aryl group, a halogen, a cyano group, a C3 to C10 cyclo It means substituted by an alkyl group or an arylalkyl group of C7 to C10.

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, a polarizer 100 according to an embodiment of the present invention may include a polarizer 110, a protective layer 120, a barrier layer 130, and an adhesive layer 140.

The polarizing plate 100 has a rate of change of the degree of polarization of Equation 1 below about 3%, specifically about 0% to about 3%, more specifically about 0% to about 1%, and more specifically about 0% to about 0.5% Can be Within this range, the polarizer has high durability at high temperature and high humidity, and can be used in an optical display device:

<Equation 1>

Change rate of polarization degree = ｜ P ₀ -P ₅₀₀ ｜ / P ₀ x 100

(In Formula 1, P ₀ is the initial polarization degree (unit:%) of the polarizing plate, P ₅₀₀ is left for 60 hours at a constant temperature and humidity of 60 ℃ and 95% relative humidity, and left for 1 hour at 25 ℃) Polarization degree of the polarizer (unit:%)).

The polarizing plate 100 may be P ₅₀₀ ≦ P ₀ in Equation 1, and P ₅₀₀ and P ₀ may each be about 90% or more, specifically, about 95.000% to about 99.990%.

The polarizing plate 100 may have a water content change rate of Equation 2 of about 10% or less, specifically about 0% to about 5%, more specifically about 0.1% to about 3%: in the above range, the high temperature of the polarizing plate Good durability at high humidity can be used for optical displays:

<Equation 2>

Moisture content change rate = ｜ W ₅₀₀ -W ₀ ｜ / W ₀ x 100

(Equation 2, W ₀ is the initial moisture content (g) of the polarizing plate, W ₅₀₀ is the moisture content of the polarizing plate after leaving the polarizing plate at a constant temperature and humidity of 60 ℃ and 95% relative humidity for 500 hours) g)).

The "moisture content" is a value calculated from the weight (A) before drying the polarizing plate and the weight (B) after drying the polarizing plate in an oven at 105 ° C for 2 hours, and calculated from | A-B |. In this case, the moisture content is a value measured for a polarizing plate having a width x length (10 cm x 10 cm).

The polarizing plate 100 may have a thickness of about 250 μm or less, specifically about 200 μm or less, and more specifically about 150 μm or less. For example, the polarizer 100 may have a thickness of about 50 μm to about 115 μm. Within this range, it can be used for an optical display device. The polarizing plate 100 may have a light transmittance of about 30% or more, specifically about 30% to about 50%, more specifically about 40% to about 49%, at a wavelength of 400 nm to 700 nm. The polarizing plate 100 may have a polarization degree of about 90% or more, specifically about 95.0000% to about 99.9999%. In the light transmittance and polarization range, the optical display device may be used.

The polarizing plate 100 has a protective layer 120 formed on one surface of the polarizer 110, a barrier layer 130 formed on the other surface of the polarizer 110, and the barrier layer 130 is a barrier layer composition as described below. Can be formed. Accordingly, the polarizing plate 100 suppresses water vapor and / or moisture infiltration into the other surface of the polarizer 110 at high temperature and high humidity, so that the polarization degree change rate of Equation 1 is about 3% or less and the water content change rate of Equation 2 is about 10% or less. Can be obtained. In addition, the polarizing plate 100 may have high modulus of the barrier layer 130 to increase crack resistance of the polarizer under thermal shock, and may have good adhesion between the polarizer 110 and the barrier layer 130.

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

Polarizer (110)

The polarizer 110 is formed between the barrier layer 130 and the adhesive layer 140, 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 polarizer in which at least one of iodine and dichroic dye is adsorbed onto the polyvinyl alcohol resin film. In addition, the polarizer may be a polyene-based polarizer prepared by dehydrating the polyvinyl alcohol-based resin film.

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

Specifically, the polyvinyl alcohol-based polarizer adsorbs at least one of iodine and dichroic dye on the polyvinyl alcohol-based resin film and has a final drawing ratio of about 2 to about 8 times, specifically about 3 to about 6 times MD (machine direction). ) Can be produced by uniaxial stretching. Stretching can include dry stretching, wet stretching, or a combination thereof. The "final draw ratio" means the ratio of the length of the final polyvinyl alcohol polarizer to the initial length of the polyvinyl alcohol resin film. After stretching, color correction may be further performed by immersion in an aqueous solution of boric acid and an aqueous solution of potassium iodide.

Specifically, the polyene polarizer may be prepared by adding an acid catalyst to the polyvinyl alcohol-based resin film and dehydrating and drying the same. The acid catalyst may comprise an organic acid, an inorganic acid or mixtures thereof including aromatic sulfonic acids, such as toluenesulfonic acid, including para-toluenesulfonic acid and the like.

The polarizer 110 may have a thickness of about 5 μm to about 100 μm, specifically about 5 μm to about 50 μm. In the above range, it can be used for the polarizing plate, and in combination with the protective layer, the adhesive layer and the barrier layer can exhibit the rate of change of polarization degree of the formula 1, the rate of change of moisture content of the formula (2). As thinning of the polarizing plate is required, the polarizer 110 may have a thickness of about 5 μm, about 6 μm, about 7 μm, about 8 μm, about 9 μm, about 10 μm, about 11 μm, or about 12 μm. It can also be made thin.

Protective layer (120)

The protective layer 120 is formed on one surface of the polarizer 110 to protect the polarizer 110, and may be formed on one surface of the polarizer 110 by the adhesive layer 140.

The protective layer 120 has a water permeability of about 30 g / m ² · 24hr or less, specifically about 1g / m ² · 24hr to about 25g / m ² · 24hr, more specifically about 5g / m ² · 24hr to about 15g / m ² may be 24hr. By preventing external moisture from penetrating the polarizer in the above range, the durability at high temperature and high humidity of the polarizing plate can be increased, and the durability at high temperature and high humidity of the polarizing plate can be further increased together with the adhesive layer.

The protective layer 120 has an in-plane retardation (Re) of the following Formula 3 at a wavelength of 550 nm of about 5,000 nm or more, about 10,000 nm or more, specifically about 5,000 nm to about 15,000 nm, more specifically about 6,000 nm to about 12,000 nm Can be. Within this range, it is possible to prevent rainbow spots from occurring when using a polarizer:

<Equation 3>

Re = (nx-ny) x d

(In Formula 3, nx and ny are refractive indices in the x- and y-axis directions of the protective layer at a wavelength of 550 nm, respectively, and d is the thickness (unit: nm) of the protective layer.

The protective layer 120 may have a biaxial crystal degree (NZ) of Equation 4 below about 1.8, specifically about 1.0 to about 1.8 at a wavelength of 550 nm: In the above range, there may be a rainbow stain removal effect due to birefringence. :

<Equation 4>

NZ = (nx-nz) / (nx-ny)

(In Formula 4, nx, ny, and nz are refractive indexes in the x-axis, y-axis, and z-axis directions of the protective layer, respectively, at a wavelength of 550 nm.

The protective layer 120 may have a thickness direction retardation (Rth) of Equation 5 below about 15,000 nm, specifically about 6,000 nm to about 12,000 nm at a wavelength of 550 nm. There may be.

<Equation 5>

Rth = ((nx + ny) / 2-nz) x d

(In Formula 5, nx, ny, and nz are refractive indexes in the x-axis, y-axis, and z-axis directions of the protective layer at a wavelength of 550 nm, respectively, and d is the thickness of the protective layer (unit: nm).

The protective layer 120 may have a wavelength of 550 nm, and any one of the refractive index nx in the x-axis direction and the refractive index ny in the y-axis direction may be about 1.65 or more. If both nx and ny are less than 1.65, or if both nx and ny are 1.65 or more, rainbow spots may occur due to birefringence due to a change in retardation value depending on incident angle and wavelength when used as a protective layer. In one embodiment, nx may be about 1.65 or greater, specifically about 1.67 to about 1.75, and ny may be about 1.45 to about 1.55. In other embodiments, ny may be about 1.65 or greater, specifically about 1.67 to about 1.72, more specifically about 1.69 to about 1.72, and nx may be about 1.45 to about 1.55. At this time, | nx-ny | may be about 0.1 to about 0.2, specifically about 0.12 to about 0.18. The viewing angle can be further improved in the above range, and rainbow spots can be prevented from occurring. In the present specification, 'x axis' is the slow axis of the protective layer, 'y axis' is the fast axis of the protective layer, z axis means the thickness of the protective layer, and the x axis, y axis, and z axis is perpendicular to each other.

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

The protective layer 120 may include an optically transparent film. Specifically, the protective layer 120 may include an optically transparent film formed of a polyester resin. Specifically, the polyester resin may include one or more from polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate and the like, but is not limited thereto. In one embodiment, the protective layer 120 is formed of one polyester resin, and may be a one layer film. Even if the protective layer 120 is a single layer film, by having the above-described moisture permeability, durability of the polarizer at high temperature and high humidity may be increased.

The protective layer 120 is a transverse direction (TD) uniaxially stretched film as described below, and the polarizer 110 is an MD uniaxially stretched film as described above. In the polarizer 100, the TD of the protective layer 120 and the MD of the polarizer 110 may be substantially orthogonal to each other. As a result, the warpage of the polarizing plate 100 can be prevented. As used herein, "substantially orthogonal" may include not only the case where the TD of the protective layer and the MD of the polarizer are orthogonal to 90 degrees, but also when there is a slight error at 90 degrees.

The protective layer 120 melt-extrudes a composition containing a polyester resin for a protective layer to produce a melt-extruded resin film, and stretches the melt-extruded resin film by TD only from about 2 times to about 10 times, and has a temperature in a predetermined range. It can be prepared by the step of heat-treatment and tension-relaxation by lowering the degree of stretching at TD.

The composition including the protective layer polyester resin may further include a conventional additive in addition to the polyester resin for the protective film. Specifically, the additive may include a UV absorber, a leveling agent, an antistatic agent, and the like. Ultraviolet absorbers can include conventional ultraviolet absorbers that absorb light having a wavelength of about 200 nm to about 400 nm. Specifically, the ultraviolet absorber may include one or more of phenol, benzotriazole, salicysilane, triazine, and oxamide. In particular, the phenolic UV absorber is highly compatible with the polyester resin and thus mixed well with the polyester resin to suppress elution in the polyester film and to suppress the generation of holes in the film or the surface, thereby improving appearance.

The melt extruded resin film is stretched about 2 to about 10 times, specifically about 3 to about 8 times, only by TD. In the draw ratio, the protective film may not generate a rainbow stain. In this case, the melt-extruded resin film may be stretched from about 1 to about 1.1 with MD. "MD stretching 1 to 1.1" means that there is no further stretching except for mechanical stretching by moving the film to the MD by a roller or the like in the TD stretching process of the melt-extruded resin film. Stretching may include one or more of dry stretching and wet stretching. The stretching temperature is about (Tg-20) ° C to about (Tg + 20) ° C, specifically about 70 ° C to about 150 ° C, more specifically about 80 ° C to about 130, relative to the glass transition temperature (Tg) of the polyester resin. ℃, even more specifically about 90 ℃ to about 120 ℃. In the stretching ratio and the temperature range, the extruded resin may be uniformly stretched.

TD stretching by heat treatment and tension-relaxation is to stretch the resin film only by TD, but crystallize and stabilize the film by heat treatment. The heat treatment is a treatment for about 1 second to about 2 hours at a temperature of at least Tg of the polyester resin, specifically from about 100 ° C to about 300 ° C. The TD draw ratio may be about 0 to about 3 times, specifically about 0.1 to about 2 times, more specifically about 0.1 to about 1 times. In the temperature and draw ratio range, the retardation value of the protective film can be maintained and the crystallization and stabilization of the film can be.

The melt-extruded resin film may further form at least one of at least one of a functional coating layer and a primer layer before TD stretching.

Although not shown in FIG. 1, the protective layer 120 may provide an additional function to the polarizer by further including a functional coating layer on one surface of the protective layer 120, for example, an upper surface of the protective layer 120. Specifically, the functional coating layer may be at least one of a hard coating layer, an antireflection layer, an anti-fingerprint layer, an antistatic layer, a low reflection layer, and the like, but is not limited thereto. The functional coating layer may have a thickness of about 1 μm to about 100 μm, specifically about 1 μm to about 50 μm, more specifically about 1 μm to about 20 μm. In the above range can provide an additional function to the polarizing plate without affecting the protective film, it can be used in the polarizing plate.

In addition, although not shown in FIG. 1, the protective layer 120 further includes a primer layer on the other surface of the protective layer 120, for example, a lower surface of the protective layer 120, so that the adhesive layer forms a polarizer and a protective layer. Better adhesion. The primer layer can be a hydrophilic surface modification layer. The primer layer may be formed by coating with a composition comprising a resin for forming a primer layer having a hydrophilic group and a hydrophobic group. The resin for forming the primer layer may include at least one of polyester resin and polyvinylacetate resin. The primer layer may have a thickness of about 1 nm to about 100 nm, specifically about 1 nm to about 50 nm, more specifically about 1 nm to about 20 nm. It is possible to increase the adhesion to the polarizer in the above range and to increase the total light transmittance.

Barrier layer (130)

The barrier layer 130 is formed on the other side of the polarizer 110 to protect the polarizer 110 from the opposite side of the protective layer 120 with respect to the polarizer 110 and external moisture penetrates into the polarizer 110. By blocking the thing, durability at high temperature and high humidity of the polarizing plate 100 can be improved.

Since the barrier layer 130 has high adhesion to the polarizer 110, the barrier layer 130 may be formed directly on the polarizer 110 to be directly formed on the polarizer 110 without the adhesive layer 140, thereby realizing a thinning effect of the polarizing plate 100. . The 'directly formed' means that no layer including an adhesive layer, an adhesive layer, or the like is interposed between the polarizer 110 and the barrier layer 130.

The barrier layer 130 may have high modulus to increase crack resistance of the polarizer 100. Specifically, the barrier layer 130 may have a modulus of about 500 MPa to about 3,000 MPa, more specifically about 1,000 MPa to about 2,500 MPa, and more specifically about 1,500 MPa to about 2,500 MPa. In the said range, the crack resistance of a polarizing plate can be improved and the curvature of a polarizing plate can be suppressed.

The barrier layer 130 may be formed on the other surface of the polarizer 110 relative to the entirety of the protective layer 120 and the adhesive layer 140 to suppress warpage of the polarizer 100. Specifically, the thickness ratio of the total thickness of the protective layer and the adhesive layer to the thickness of the barrier layer is about 5: 1 to about 100: 1, specifically about 10: 1 to about 50: 1, more specifically about 10: 1 to about 30: 1, more specifically about 10: 1 to 20: 1. The warpage of the polarizing plate can be suppressed in the above range. The barrier layer 130 has a high barrier layer modulus and can sufficiently suppress warpage of the polarizing plate even in the above-described thickness ratio range.

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

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

The barrier layer 130 may be formed of a barrier layer composition. The barrier layer composition is a curing composition, specifically a photocuring composition, and may be cured with an active energy ray including ultraviolet rays, electron beams, and the like. Hereinafter, the composition for barrier layers is demonstrated in detail.

The barrier layer composition may include a curable component and an initiator. As used herein, the term "curable component" means a component that can be cured by an active energy ray in the barrier layer composition. The curable component may be included in one or two or more compositions for the barrier layer.

The barrier layer composition may include a (meth) acrylate having a glass transition temperature (Tg) of about 50 ° C. or more as a curable component and a compound represented by the following Chemical Formula 1, and may include an initiator:

<Formula 1>

(In Formula 1, R ₁ and R ₂ are each independently an unsubstituted or substituted C1 to C20 alkyl group, R ₃ is hydrogen or a vinyl group).

The (meth) acrylate having a glass transition temperature (Tg) of about 50 ° C. or more can increase the mechanical strength and modulus of the barrier layer to increase durability and moisture resistance at high temperature and high humidity of the polarizing plate. The (meth) acrylate having a glass transition temperature (Tg) of about 50 ° C. or more can increase the mechanical strength and modulus of the barrier layer to increase the crack resistance of the polarizer under the thermal shock of the polarizing plate. The (meth) acrylate having a glass transition temperature (Tg) of about 50 ° C. or more may be cured by radicals by active energy rays. The (meth) acrylate having a glass transition temperature of about 50 ° C. or more may be stably cured without being inhibited by the external moisture or the moisture of the polarizer. The (meth) acrylate having a glass transition temperature (Tg) of about 50 ° C. or more has good adhesion to the polarizer and thus can bond the polarizer and the barrier layer without an adhesive layer.

The (meth) acrylate having a glass transition temperature (Tg) of about 50 ° C. or higher specifically includes a glass transition temperature of about 60 ° C. or higher, more specifically about 80 ° C. or higher, for example, about 60 ° C. to about 200 ° C. (Meth) acrylate that is from 60 ° C to about 150 ° C. Within the glass transition temperature range, crack resistance under thermal shock due to an increase in modulus of the barrier layer may be increased.

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

Specifically, the (meth) acrylate having a glass transition temperature (Tg) of about 50 ° C. or more 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, neopentylglycolpropoxylate di (meth) acrylate, neopentylglycol di (meth) acrylate, tri (propylene glycol) di (meth) acrylate and di One or more of poly (alkylene glycol) di (meth) acrylates including propylene 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 about 50 ° C. or more has an isocyanurate group, including tris (2-hydroxyethyl) isocyanurate di (meth) acrylate ( By including meth) acrylate, the durability at high temperature and high humidity of a polarizing plate can be improved further.

More specifically, the (meth) acrylate having a glass transition temperature (Tg) of about 50 ° C. or more may further increase durability at high temperature and high humidity of the polarizing plate by including poly (alkylene glycol) di (meth) acrylate. .

The (meth) acrylate having a glass transition temperature (Tg) of about 50 ° C. or more is about 20 wt% to about 95 wt%, specifically about 20 wt% to about 90 wt% of the total sum of the curable components of the composition for a solids-based barrier layer. And, more specifically, about 60% to about 95% by weight, about 60% to about 80% by weight. In the above range, the glass transition temperature of the barrier layer composition and the modulus of the barrier layer may be increased to increase durability at high temperature and high humidity of the polarizing plate, and may improve adhesion to the polarizer.

The compound of formula 1 is excellent in water resistance and water repellency. Accordingly, the compound of Formula 1 prevents the penetration of water vapor and / or water of the barrier layer with (meth) acrylate having a glass transition temperature of about 50 ° C. or higher to increase water resistance and moisture resistance at high temperature and / or high humidity of the polarizing plate, and And / or it is possible to prevent the discoloration of the polarizer by water to lower the rate of change of polarization degree of the polarizing plate. In particular, the vinyl ester of the formula (compound in which R ₃ is a vinyl group) is not deteriorated by the active energy ray, so that discoloration of the polarizing plate may be suppressed.

The compound of formula 1 may be included alone or in combination of two or more. Specifically, in Formula 1, R ₁ and R ₂ may be each independently 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 about 6 to about 8, specifically about 6, about 7, or about 8. Specifically, in Formula 1, R ₃ may be a vinyl group, and the compound of Formula 1 may be a vinyl ester. At this time, the polarization degree content rate and the moisture content change rate of the polarizing plate may be lowered. The compound of Formula 1 may include one or more of commercially available products VeoVa-9, VeoVa-10, VeoVa-11 (or more, Momentive, Inc.), versatic acid (Hexicon, Ltd.). In particular, VeoVa-10 has excellent adhesiveness, water resistance, and water repellency, and does not cause deterioration by UV, and thus has strong characteristics against discoloration.

About 5 wt% to about 80 wt%, specifically about 5 wt% to about 70 wt%, more specifically about 5 wt% to about 40 wt% of the total sum of the curable components of the composition for barrier solids based on the compound of formula 1 For example, about 10% to about 40% by weight. Within this range, the water resistance of the polarizing plate may be improved, and the glass transition temperature of the barrier layer may not be lowered, and thus the crack resistance of the polarizer may be excellent.

The initiator can cure the curable component. The initiator may comprise one or more of a photoradical initiator, a photocationic initiator. The initiator may be used alone or in combination of two or more thereof.

The photoradical initiator may be one known to those skilled in the art. Specifically, the optical radical initiator may use at least one of thioxanthone, phosphorus, triazine, acetophenone, benzophenone, benzoin and oxime. Specifically, photoradical initiators are phosphorus based, for example diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, bis (2,6-dimethoxybenzoyl) (2,4,4-trimethylpentyl) phosphine oxide Etc. can be used.

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

The initiator may be included in an amount of about 0.1 part by weight to about 10 parts by weight, specifically about 1 part by weight to about 6 parts by weight, based on 100 parts by weight of the total amount of the curable component in the composition for the solid content barrier layer. In the above range, the curable component can be sufficiently cured, and the residual amount of initiator can remain to prevent the transparency of the barrier layer from decreasing.

In one embodiment, the barrier layer composition comprises about 20% to about 95% by weight of (meth) acrylate having a glass transition temperature (Tg) of about 50 ° C. or more, and about 5% to about 80% of the compound of Formula 1 And about 0.1 part to about 10 parts by weight of initiator based on 100 parts by weight of the total amount of the curable component, including the curable component.

The barrier layer composition may further include a trifunctional or higher polyfunctional (meth) acrylate as the curable component.

The trifunctional or higher polyfunctional (meth) acrylate can improve the crosslinking density of the barrier layer to increase the cohesive energy of the barrier layer and increase the reliability. Trifunctional or higher polyfunctional (meth) acrylates can be cured in response to radicals initiated by light energy. Specifically, the tri- or multi-functional (meth) acrylate may be a tri- or 6-functional poly-functional (meth) acrylate, more specifically, a tri-, tetra-, 5- or 6-functional (meth) acrylate. Can be.

Specifically, trifunctional or higher polyfunctional (meth) acrylates are unsubstituted, glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tri (meth) acrylate, ditrimethylol Propane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, Polyfunctional (meth) acrylates of unsubstituted trifunctional or higher aliphatic polyols such as dipentaerythritol hexa (meth) acrylate. The trifunctional or higher trifunctional (meth) acrylates include polyfunctional (meth) acrylates of halogen-substituted aliphatic polyols, tri (meth) acrylates of alkylene oxide adducts of glycerin, and trialkylol adducts of alkylene oxide adducts of trimethylolpropane. Meth) acrylate, 1,1,1-tris [(meth) acryloyloxyethoxyethoxy] propane, tris (hydroxyethyl) isocyanurate tri (meth) acrylate, 6 functional polyester acrylic It may include one or more of the rate (PS-610, Miwon Corp.).

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

The trifunctional or higher polyfunctional (meth) acrylate is about 10% by weight or less, specifically about 0.1% by weight to about 10% by weight, more specifically about 1% by weight to about 10% by weight, based on the total amount of the curable components of the composition for the solid content barrier layer. 10 weight percent, for example, about 1 weight percent, 2 weight percent, 3 weight percent, 4 weight percent, 5 weight percent, 6 weight percent, 7 weight percent, 8 weight percent, 9 weight percent, or 10 weight percent have. In the above range, the barrier layer may have high reliability, no curing shrinkage of the barrier layer composition may occur, and adhesiveness may not decrease, and the cutting property of the polarizing plate may be good.

Since the trifunctional or higher polyfunctional (meth) acrylate is a radically polymerizable compound like the (meth) acrylate having a glass transition temperature (Tg) of about 50 ° C. or higher, the content ratio is important for enhancing the effect of the barrier layer and the polarizing plate. The trifunctional or higher polyfunctional (meth) acrylate is about 20% by weight or less of the sum of the (meth) acrylate having a glass transition temperature (Tg) of about 50 ° C or higher and the trifunctional or higher polyfunctional (meth) acrylate, specifically about 5 Weight percent to about 20 weight percent. In the above range, there is little hardening shrinkage so that the decrease in adhesion may not occur and poor cutting properties may not occur.

In one embodiment, the composition for the barrier layer is about 20% to about 90% by weight (meth) acrylate having a glass transition temperature (Tg) of about 50 ° C. or more, and about 5% to about 70% by weight of the compound of Formula 1 %, And from about 0.1 part to about 10 parts by weight of the curable component comprising about 0.1% to about 10% by weight of a trifunctional or higher polyfunctional (meth) acrylate, based on 100 parts by weight of the total amount of the curable component. Can be.

The barrier layer composition may further include a solvent-free composition containing no solvent, or a solvent in order 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. The additive may provide additional functionality to the barrier layer. Specifically, the additive may include one or more of a UV absorber, a reaction inhibitor, an adhesion enhancer, a thixotropic imparting agent, a conductivity imparting agent, a color regulator, a stabilizer, an antistatic agent, an antioxidant, a leveling agent, and the like, but is not limited thereto. It doesn't work.

The barrier layer composition may have a viscosity of about 5 cPs to about 200 cPs, specifically about 10 cPs to about 150 cPs at 25 ° C. The coating property of the barrier layer may be good within the above range, so that the barrier layer may be easily formed.

Adhesive Layer 140

The adhesive layer 140 may be formed between the polarizer 110 and the protective layer 120 to bond the polarizer 110 and the protective layer 120.

The adhesive layer 140 may have a thickness of about 5 μm or less, specifically about 1 μm to about 4 μm. In the above range, it can be used for the polarizing plate.

Since the adhesive layer 140 is formed of an active energy ray-curable adhesive composition, the adhesive layer 140 may increase durability at high temperature and high humidity of the polarizing plate together with the protective layer, and may have a crack resistance effect.

The active energy ray-curable adhesive composition may include an epoxy compound, a (meth) acrylic compound, and an initiator.

The epoxy compound may include an alicyclic epoxy compound, an aromatic epoxy compound, an aliphatic epoxy compound, a hydrogenated epoxy compound, or a mixture thereof. The epoxy compound may include a non- (meth) acrylate compound without a (meth) acrylate group.

The alicyclic epoxy compound may be a compound having one or more epoxy groups in the alicyclic ring. The alicyclic epoxy compound may be an alicyclic diepoxy carboxylate. In an embodiment, 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclo Hexane-meth-dioxane, bis (3,4-epoxycyclohexylmethyl) adipate, bis (3,4-epoxy-6-methylcyclohexyl) adipate, 3,4-epoxy-6-methylcyclohexyl- 3 ', 4'-epoxy-6'-methylcyclohexanecarboxylate, ε-caprolactone modified 3,4-epoxycyclohexylmethyl-3', 4'-epoxycyclohexanecarboxylate, trimethylcaprolactone modified 3 , 4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate, β-methyl-δ-valerolactone modified 3,4-epoxycyclohexylmethyl-3', 4'-epoxycyclohexanecarbox Carboxylate, methylenebis (3,4-epoxycyclohexane), di (3,4-epoxycyclohexylmethyl) ether of ethylene glycol, ethylenebis (3,4-epoxycyclohexanecarboxylate), epoxycyclohexahydrate Dioctyl phthalate, and the like epoxy hexahydrophthalic acid di-2-ethylhexyl cyclohexane.

Aromatic epoxy compounds include bisphenol A, F, and phenol noblock, cresol noblock, bisphenol A-noblock, dichloropentadiene noblock, glycidyl ether of triphenolmethane, triglycidyl paraaminophenol, tetraglycidyl methylene di Aniline and the like.

Specific examples of the aliphatic epoxy compound include 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylol propane triglycidyl ether, and polyethylene glycol. Diglycidyl ether, glycerin triglycidyl ether, polypropylene glycol diglycidyl ether; Polyglycidyl ethers of polyether polyols obtained by adding one or two or more alkylene oxides to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol and glycerin; Diglycidyl esters of aliphatic long-chain dibasic acids; Monoglycidyl ethers of aliphatic higher alcohols; Glycidyl ethers of higher fatty acids; Epoxidized soybean oil; Butyl epoxystearate; Octyl epoxystearate; Epoxidized flax oils; Epoxidized polybutadiene etc. are mentioned.

The hydrogenated epoxy compound means a resin obtained by selectively hydrogenating an aromatic epoxy resin under pressure in the presence of a catalyst. Examples of the aromatic epoxy resins include bisphenol type epoxy resins such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, and diglycidyl ether of bisphenol S; Novolac type epoxy resins such as phenol novolac epoxy resins, cresol novolac epoxy resins, hydroxybenzaldehyde phenol novolac epoxy resins; And polyfunctional epoxy resins such as glycidyl ether of tetrahydroxyphenylmethane, glycidyl ether of tetrahydroxybenzophenone, and epoxidized polyvinyl phenol. Although the mother nucleus hydrogenated products of these aromatic epoxy resins become a hydrogenated epoxy resin, it is preferable to use the glycidyl ether of the hydrogenated bisphenol A among these.

The (meth) acrylic compound may include at least one of a monofunctional (meth) acrylate having one (meth) acrylate group and a bifunctional (meth) acrylate having two (meth) acrylate groups. By containing one or more hydroxyl groups, the (meth) acrylic compound can enhance the adhesion to the polarizer. Specifically, the (meth) acrylic compound is 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (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, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, 4-hydroxycyclopentyl (meth) acrylate, 2-hydroxy- One or more of 3-phenyloxybutyl (meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate.

The epoxy compound may be included in an amount of about 50 parts by weight to about 90 parts by weight and the (meth) acrylic compound may be included in an amount of about 10 parts by weight to about 50 parts by weight based on 100 parts by weight of the epoxy compound and the (meth) acrylic compound. In the above range, the adhesion to the polarizer may be good.

The initiator can cure the epoxy compound and the (meth) acrylic compound. The initiator may comprise one or more of a photocationic initiator, a photoradical initiator. The initiator may be used alone or in combination of two or more thereof. Details of the photocationic initiator and the photoradical initiator are as described above.

The initiator may be included in an amount of about 0.1 part by weight to about 10 parts by weight, specifically about 1 part by weight to about 6 parts by weight, based on 100 parts by weight of the total amount of the epoxy-based compound and the (meth) acrylic compound. In the above range, the epoxy compound and the (meth) acrylic compound can be sufficiently cured, and it is possible to prevent the transparency of the adhesive layer from falling off with a residual amount of initiator.

Hereinafter, a method of manufacturing a polarizing plate according to an embodiment of the present invention will be described.

In the polarizing plate according to the embodiment of the present invention, the composition for the adhesive layer is applied to one surface of the protective layer, laminated with one surface of the polarizer, the composition for the barrier layer is applied to the other surface of the polarizer, and the composition for the adhesive layer and the barrier layer composition are cured. It can be prepared by the step of.

The composition for the adhesive layer and the composition for the barrier layer can each be applied by a conventional coating method. Specifically, it may be applied by die coating, gravure coating and the like. Curing may comprise irradiation of about 100mW / cm ² to about 2,000mW / cm ^2, from about 100mJ / cm ² to about 2,000mJ / cm ² from the UV to the active energy ray-specifically. The polarizing plate may be prepared at about 22 ° C. to about 25 ° C., and about 20% to about 60% relative humidity.

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

2, the polarizer 200 according to another embodiment of the present invention may include a polarizer 110, a protective layer 120, a barrier layer 130, an adhesive layer 140, and an adhesive layer 150. have. In the polarizing plate according to the present exemplary embodiment, the adhesive layer 150 is formed on the lower surface of the barrier layer 130, thereby adhering the polarizing plate to the panel for an optical display device such as a liquid crystal panel. Except that the adhesive layer is further formed is substantially the same as the polarizing plate according to an embodiment of the present invention. Therefore, below, only an adhesion layer is demonstrated.

The adhesive layer 150 may be formed on the bottom surface of the barrier layer to adhere the polarizer to the panel.

The adhesive layer 150 may have a modulus of about 0.5 MPa or less, specifically about 0.001 MPa to about 0.5 MPa, about 0.01 MPa to about 0.1 MPa. In the above range, when the protective layer, the adhesive layer, the polarizer and the barrier layer are laminated, the warpage is minimized and the crack resistance may be excellent by alleviating the stress that the polarizer may have. Specifically, the polarizing plate 200 may have a warpage of about 3 mm or less, specifically about 0 mm to about 2.5 mm. In the above range, it can be used as a polarizing plate.

The adhesive layer 150 may have a thickness of about 5 μm to about 40 μm, specifically about 10 μm to about 30 μm. In the above range, it can be used for the polarizing plate.

The adhesive layer 150 may be formed of a composition for a pressure-sensitive adhesive layer containing a (meth) acrylic copolymer and a crosslinking agent. Hereinafter, the composition for adhesion layers is demonstrated.

The composition for pressure-sensitive adhesive layers 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 an (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) acryl It may include one or more of the rates. 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 be. These may be included alone or in combination of two or more.

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

The (meth) acrylic copolymer may be prepared by a conventional method. Specifically, it can be prepared by adding an initiator to the monomer mixture and reacting at about 50 ° C to about 100 ° C. The initiator may use 2,2'-azobisisobutyronitrile (AIBN) and the like, but is not limited thereto. The initiator may be included in about 0.01 part by weight to about 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.

A crosslinking agent hardens a (meth) acrylic-type copolymer, and can contain a conventional isocyanate crosslinking agent. Specifically, the crosslinking agent may include one or more of hexamethylene diisocyanate, tolylene diisocyanate, xylene diisocyanate, isophorone diisocyanate, naphthalene diisocyanate, trimethylolpropane modified tolylene diisocyanate adduct. The crosslinking agent may be included in about 0.1 part by weight to about 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 well crosslinked to implement the adhesive effect.

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

The silane coupling agent may increase the adhesive force of the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition. As the silane coupling agent, epoxy group-containing silane coupling agents such as glycidoxypropyltrimethoxysilane and glycidoxypropylmethyldimethoxysilane can be used. The silane coupling agent may be included in an amount of about 0.1 part by weight to about 5 parts by weight based on 100 parts by weight of the (meth) acrylic copolymer. In the above range, there may be an adhesive improvement effect. The crosslinking catalyst can increase the degree of crosslinking of the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition. The crosslinking catalyst may comprise one or more of metals, or metal containing compounds. Specifically, the crosslinking catalyst may include one or more of tin-containing compounds, zinc-containing compounds, titanium compounds, bismuth compounds. More specifically, the crosslinking catalyst may comprise one or more of dibutyltindilaurate, dimaleatetin. The crosslinking catalyst may be included in an amount of about 0.01 parts by weight to about 1.5 parts by weight based on 100 parts by weight of the (meth) acrylic copolymer. In the above range, the degree of crosslinking of the pressure-sensitive adhesive composition can be increased and moisture penetration can be suppressed.

An 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, but is not limited thereto.

Hereinafter, an optical display device according to an exemplary embodiment of the present invention will be described with reference to FIG. 3. 3 is a cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the liquid crystal display device 300 according to an exemplary embodiment of the present invention includes a liquid crystal panel 310, a first polarizing plate 320 formed on one surface of the liquid crystal panel 310, and another surface of the liquid crystal panel 310. A second polarizing plate 330 formed in the, and the backlight unit 340 is located on the lower surface of the second polarizing plate 330, the first polarizing plate 320 may include a polarizing plate according to embodiments of the present invention have.

The liquid crystal panel 310 may be formed between the first polarizing plate 320 and the second polarizing plate 330 to transmit light incident from the second polarizing plate to the first polarizing plate 320. The liquid crystal panel 310 includes a liquid crystal layer, and the liquid crystal layer includes an in plane switching (IPS) mode, a twist nematic (TN) mode, a vertical alignment (VA) mode, a patterned vertical alignment (PVA) mode, and an S-PVA (super) -patterned vertical alignment mode can be adopted.

The second polarizing plate 330 may include a conventional polarizing plate including a polarizer and a protective film formed on at least one surface of the polarizer. The polarizer polarizes light incident from the backlight unit 340 and may include a conventional polarizer known to those skilled in the art. The protective film is an optically transparent film, a cellulose resin, a polyacetal resin, including a polyester resin containing a polyethylene terephthalate resin, a polyethylene naphthalate resin and the like, a cycloolefin polymer (COP) resin, a triacetyl cellulose resin, and the like. , Non-cyclic polyolefin resins, acrylonitrile-butadiene-styrene copolymer resins, including acrylic resins, polycarbonate resins, styrene resins, vinyl resins, polyphenylene ether resins, polyethylene, polypropylene, and the like, The film may include at least one of polyacrylate resin, polyaryl sulfone resin, polyether sulfone resin, polyphenylene sulfide resin, fluorine resin, and (meth) acrylic resin.

The backlight unit 340 may include a light guide plate, a light source, a reflective sheet, a diffusion sheet, and the like.

3 illustrates a case in which the first polarizing plate 320 is a polarizing plate according to embodiments of the present invention. However, the case where the second polarizing plate 330 is a polarizing plate according to embodiments of the present invention and the first polarizing plate 310 is the above-described conventional polarizing plate may also be included in the scope of the present invention. In addition, a case in which both the first polarizing plate 320 and the second polarizing plate 330 are polarizing plates according to embodiments of the present invention may also be included in the scope of the present invention.

Hereinafter, the configuration and operation of the present invention through the embodiments of the present invention will be described in more detail. However, the following examples are provided 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 the Examples and Comparative Examples are as follows.

A) Tris (2-hydroxyethyl) isocyanurate diacrylate (Tg: 131 degreeC, M-2370, Miwon Corporation)

B) Tri (propylene glycol) diacrylate (Tg: 62 ° C, M-220, Miwon Corporation)

C) VeoVa-10 (Tg: -3 ° C, Momentive)

D) versatic acid (Hexion)

E) pentaerythritol tetraacrylate (Tg: 65 ° C, M-420, Miwon Corporation)

F) 6 functional polyester acrylate (PS-610, Miwon Corporation)

G) Butyl acrylate (Tg: -54 ℃, LG Chem)

H) diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (Darocure TPO, Ciba)

I) Protective layer: polyethylene terephthalate film, water transmittance: 10g / m ² ㆍ 24hr, Re: 10,200nm, Rth: 12,000nm, thickness: 80㎛ at wavelength 550nm, Toyobo

* The moisture permeability of the protective layer is measured at 40 ° C and 90% relative humidity in accordance with KS A1013.

Example One

(1) polarizer manufacturing

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

(2) Preparation of composition for adhesive layer

60 weight part of CELLOXIDE 2021P and 40 weight part of 2-hydroxyethyl methacrylates were mixed, 1 weight part of Darocure TPO, and 2 weight part of Irgcure were further mix | blended, and the composition for adhesive layers was prepared.

(3) Preparation of composition for barrier layer

80 weight part of tris (2-hydroxyethyl) isocyanurate diacrylate, 10 weight part of VeoVa-10, and 10 weight part of pentaerythritol tetraacrylate were mixed, and the curable component was obtained. To the curable component, 2 parts by weight of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (Darocure TPO, Ciba) was blended to prepare a barrier layer composition.

(4) polarizing plate manufacturing

Polarizing plate was prepared at 22 ℃ to 25 ℃, relative humidity 20% to 60%. The composition for the adhesive layer was applied to one surface of the protective layer and laminated with one surface of the polarizer. The barrier layer composition was coated on the other side of the polarizer and irradiated with ultraviolet light at 400 mW / cm ² and 1000 mJ / cm ² with a metal halide lamp to provide a barrier layer (thickness: 5 µm), a polarizer (thickness: 23 µm), and an adhesive layer (thickness). : 3 micrometers) and the polarizing plate in which the protective layer (thickness: 80 micrometers) were formed one by one were manufactured.

Example  2 to Example  9 and Comparative example  One

In Example 1, the polarizing plate was manufactured by the same method except the composition for barrier layers using the curable component which mixed following Table 1 (unit: weight part) as a curable component of the composition for barrier layers.

Example  10

1 part by weight of 4-hydroxybutyl acrylate and 99 parts by weight of N-butyl acrylate were added to a 1 L reactor equipped with a refrigeration device to allow nitrogen gas to reflux and easy temperature control, and 120 parts by weight of ethyl acetate was added. Nitrogen gas was purged for 60 minutes to remove oxygen, and then maintained at 60 ° C., and 0.03 parts by weight of 2,2′-azobisisobutyronitrile (AIBN), a reaction initiator, was diluted with ethyl acetate at 45% concentration. . An acrylic copolymer was prepared by reacting at 60 ° C. for 8 hours. The weight average molecular weight (polystyrene conversion value) of the prepared acrylic copolymer was 1600000 g / mol. 100 parts by weight of the prepared acrylic copolymer, 0.125 parts by weight of adduct (L-45 Soken) of trimethylolpropane-modified tolylene diisocyanate as a curing agent, 0.125 parts by weight of dibutyltin dilaurate (Sokken, accelerator S), and gly 0.3 parts by weight of cydoxypropyl trimethoxysilane (Shin-Yestsu, KBM403) was added to methyl ethyl ketone as a solvent to prepare a pressure-sensitive adhesive composition.

The adhesive layer was coated on a release film and cured at 35 ° C. and a relative humidity of 45% to prepare a 25 μm thick adhesive film, and a plurality of layers were laminated to a 0.8 mm thick and 8 mm diameter ARES (Advanced Rheometric Expansion System). , TA instrument, parallel plate fixture, temperature sweep test (strain 5%, normal force 100N, 0 ° C to 100 ° C (raising rate: 10 ° C / min)) at 23 ° C and 1Hz The measured modulus was 0.08 MPa at 23 ° C.

In the same manner as in Example 1, a polarizer, an adhesive layer composition, and a barrier layer composition were prepared.

Polarizing plate was prepared at 22 ℃ to 25 ℃, relative humidity 20% to 60%. The above prepared adhesive layer composition was applied to the protective layer and laminated on one surface of the polarizer. On the other side of the polarizer was applied the composition for the barrier layer prepared above and irradiated with ultraviolet light at 400mW / cm ² , 1000mJ / cm ² with a metal halide lamp. The pressure-sensitive adhesive film was prepared by applying the prepared pressure-sensitive adhesive layer composition to a release film (polyethylene terephthalate film). The adhesive film is laminated on the barrier layer, aged at 35 ° C. and 45% relative humidity for 48 hours to form an adhesive layer (thickness: 20 μm), barrier layer (thickness: 5 μm), polarizer (thickness: 23 μm), and adhesive layer ( Thickness: 3 micrometers) and the polarizing plate in which the protective layer (thickness: 80 micrometers) were formed one by one were manufactured.

	Barrier layer
	(Meth) acrylate of Tg 50 ° C or higher		Compound of Formula 1		Trifunctional or higher (meth) acrylate		(Meth) acrylate below Tg 50 ° C
	A	B	C	D	E	F	G
Example 1	80	-	10	-	10	-	-
Example 2	60	20	20	-	-	-	-
Example 3	60	-	30	-	10	-	-
Example 4	40	20	35	-	5	-	-
Example 5	50	20	25	-	-	5	-
Example 6	10	50	35	-	-	5	-
Example 7	70	-	30	-	-	-	-
Example 8	10	60	20	-	10	-	-
Example 9	60	20	-	20	-	-	-
Example 10	80	-	10	-	10	-	-
Comparative Example 1	50	-	-	-	10	-	40

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

	Adhesiveness	Foundation	Crack resistance	High temperature and high humidity durability		Modulus of barrier layer (25 ℃, MPa)
				% Change in polarization degree	Moisture content change rate (%)
Example 1	○	○	×	0.2	2.9	2100
Example 2	○	○	×	0.1	1.2	1850
Example 3	◎	○	×	0.1	1.1	1800
Example 4	◎	○	×	0.1	1.6	1780
Example 5	◎	◎	×	0.1	0.6	1700
Example 6	◎	◎	×	0.1	0.9	1600
Example 7	○	◎	×	0.1	0.8	1900
Example 8	○	◎	×	0.1	2.0	1950
Example 9	○	◎	×	0.3	2.8	1900
Example 10	○	○	×	0.2	2.9	2100
Comparative Example 1	○	◎	○	4.4	6.1	1450

As shown in Table 2, the polarizing plate according to the present embodiment had good durability at high temperature and high humidity. In addition, the polarizing plate according to the present embodiment has good adhesion and cutting property between the barrier layer and the polarizer, and has good crack resistance, so that cracks of the polarizer may not be generated even if the polarizing plate is left to thermal shock.

On the other hand, the polarizing plate of Comparative Example 1, which does not include (meth) acrylate having a glass transition temperature of 50 ° C. or more, or the compound of Formula 1, has poor crack resistance or poor high temperature and high humidity durability of the polarizing plate.

(1) Adhesiveness: The cutter blade tip was inserted between the barrier layer of the edge part of a polarizing plate, and a polarizer. ◎ which did not enter between a barrier layer and a polarizer was (circle), the thing which entered a little knife edge (circle) and a knife edge entered a little, but there was constant strength, (triangle | delta) and (triangle | delta) that the barrier layer was torn in the middle were evaluated by X.

(2) Cutting property: The polarizing plate was punched from the protective layer side in the size of width x length (500 mm x 500 mm) using a cutter blade. The peeling state of the edge part of 4 punched polarizing plates was visually observed. (Circle) that the barrier layer did not peel off, (circle) that the barrier layer peeled 1 mm or less, (triangle | delta) that the barrier layer peeled more than 1 mm and 2 mm or less, (triangle | delta) and the barrier layer peeled more than 2 mm were evaluated by X.

(3) Crack resistance: The crack resistance under thermal shock of the polarizing plate was evaluated. A sample was prepared by laminating a polarizing plate having a width x length (50 mm x 50 mm) on a glass plate. The sample was left at -40 ° C for 30 minutes, heated at -40 ° C to 85 ° C, and left at 85 ° C for 30 minutes to perform 200cycles to give a thermal shock. The sample was visually confirmed whether cracks were generated by MD of the polarizer in the reflection mode under the fluorescent lamp and the back light mode. When no crack occurred at all, X was evaluated.

(4) the degree of polarization change: was measured W x (25mmx25mm) initial degree of polarization (P ₀₎ of the polarizer at a wavelength of 400nm to 700nm by using the V-7170 (Jasco社) after laminating a polarizing plate on the glass plate the center of the. The polarizing plate was left at 60 ° C. and 95% relative humidity for 500 hours, and then left at 25 ° C. for 1 hour, and then the polarization degree (P ₅₀₀ ) of the polarizing plate was measured at a wavelength of 400 nm to 700 nm using V-7170 (Jasco). It was. The polarization degree change rate was calculated according to the above formula 1.

(5) Moisture content change rate: The weight (A ₀ ) before drying the horizontal x vertical (10 cm x 10 cm) sized polarizing plate is measured, and the weight (B ₀ ) after drying the polarizing plate in an oven at 105 ° C. for 2 hours. Measured. A ₀ -B ₀ is the initial moisture content (W ₀ ) of the polarizing plate. After the polarizer was left at 60 ° C. and 95% relative humidity for 500 hours, the weight of the polarizer (A ₅₀₀ ) was measured, and the weight (B ₅₀₀ ) after drying the polarizer for 2 hours in a 105 ° C. oven was measured. A ₅₀₀ -B ₅₀₀ is the moisture content (W ₅₀₀ ) of the polarizing plate after the polarizing plate is left for 500 hours at 60 ° C. and 95% relative humidity. The change rate of water content was calculated from the above formula 2.

(5) Modulus of barrier layer: The composition for barrier layers of Examples and Comparative Examples was coated on a release film with a thickness of 50 μm and irradiated with 400 mW / cm ² and 1000 mJ / cm ² with a metal halide lamp to remove the release film, Specimens were prepared by cutting to width x length x thickness (10 mm x 100 mm x 50 μm). Using the DMA Q800 (TA Instrument Co., Ltd.), the specimen was measured in the tension mode, temperature increase rate 5 ° C./min, temperature range 0 ° C. to 100 ° C., frequency 1 Hz, strain 5%, and the value at 25 ° C. was measured. Modulus was taken.

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 seen to be included in the scope of the present invention.

Claims (16)

1. A polarizer comprising a polarizer, an adhesive layer formed on an upper surface of the polarizer, a protective layer formed on an upper surface of the adhesive layer and having a water permeability of about 30 g / m ² · 24hr or less, and a barrier layer formed on a lower surface of the polarizer,

   The polarizing plate has a rate of change of the degree of polarization of Formula 1 below about 3%,

   The polarizing plate is a polarizing plate having a water content change rate of the following Formula 2 is about 10% or less:

   <Equation 1>

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

   (In Formula 1, P ₀ is the initial polarization degree of the polarizing plate, P ₅₀₀ is the polarizing degree of the polarizing plate after leaving the polarizing plate for 500 hours at a constant temperature and humidity of 60 ℃ and 95% relative humidity for 1 hour at 25 ℃ ),

   <Equation 2>

   Moisture content change rate = ｜ W ₅₀₀ -W ₀ ｜ / W ₀ x 100

   (In Formula 2, W ₀ is the initial moisture content of the polarizing plate, W ₅₀₀ is the moisture content of the polarizing plate after leaving the polarizing plate for 500 hours at a constant temperature and humidity of 60 ℃ and 95% relative humidity).
2. The polarizing plate of claim 1, wherein the barrier layer is formed of a (meth) acrylate having a glass transition temperature (Tg) of about 50 ° C. or more, a compound represented by the following Formula 1, and an initiator:

   <Formula 1>

   

   (In Formula 1, R ₁ and R ₂ are each independently an unsubstituted or substituted C1 to C20 alkyl group, R ₃ is hydrogen or a vinyl group).
3. The polarizing plate according to claim 2, wherein the (meth) acrylate having a glass transition temperature (Tg) of about 50 ° C. or more has an isocyanurate group.
4. The polarizing plate of claim 2, wherein the (meth) acrylate having a glass transition temperature (Tg) of about 50 ° C. or more includes a monofunctional (meth) acrylate, a bifunctional (meth) acrylate, or a mixture thereof. .
5. The polarizing plate of claim 2, wherein in Formula 1, R ₃ is a vinyl group.
6. The polarizing plate of claim 2, wherein in Formula 1, R ₁ and R ₂ are alkyl groups such that the total carbon number of R ₁ and R ₂ is 6 to 8. 8.
7. The polarizing plate according to claim 2, wherein the composition for the barrier layer further comprises a trifunctional or higher polyfunctional (meth) acrylate.
8. The polarizing plate of claim 1, wherein the barrier layer has a thickness of about 2 μm to about 12 μm.
9. The polarizer of claim 1, wherein the barrier layer has a modulus of about 500 MPa to about 3,000 MPa.
10. The polarizing plate of claim 1, wherein the protective layer comprises a film formed of at least one of polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and polybutylene naphthalate.
11. The polarizing plate of claim 1, wherein the protective layer has an in-plane retardation (Re) of about 5,000 nm or more.

    <Equation 3>

    Re = (nx-ny) x d

    (In Formula 3, nx and ny are refractive indices in the x- and y-axis directions of the protective layer at a wavelength of 550 nm, respectively, and d is the thickness (unit: nm) of the protective layer.
12. The polarizing plate of claim 1, wherein a thickness ratio of the thickness of the entire protective layer and the adhesive layer to the thickness of the barrier layer is about 10: 1 to about 50: 1.
13. The polarizing plate of claim 1, wherein an adhesive layer is further formed on a lower surface of the barrier layer.
14. The polarizing plate of claim 13, wherein the modulus of the adhesive layer is 0.001 MPa to 0.5 MPa.
15. The polarizing plate of claim 1, wherein the polarizing plate has a thickness of about 250 μm or less.
16. An optical display device comprising the polarizing plate of any one of claims 1 to 15.

Images