WO2016171389A1 - Polarizing plate and optical display apparatus including same - Google Patents

Abstract

The present invention relates to a polarizing plate comprising: a polarizer; a protective film formed on one surface of the polarizer; and an adhesive layer formed on another surface of the polarizer, wherein the adhesive layer comprises (meth)acrylic copolymers and has a moisture permeability of 5g/m²/24h or less. The polarizing plate has excellent durability at high temperatures and high moisture and includes the adhesive layer having superior adhesiveness to the polarizer and increasing crack-resistance of the polarizer, thereby enabling the protective film to be omitted such that the polarizing plate is made to be thin.

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.

The polarizer includes an iodine-based compound or a dichroic polarizing material arranged in a predetermined direction, and in order to protect the polarizer, a plurality of layers are formed on both sides of the polarizer by using a protective film such as a triacetyl cellulose (TAC) system. do. In addition, the polarizing plate may additionally include an optical film such as a retardation film or a liquid crystal film.

Recently, the market for thin-film liquid crystal display devices such as slim large wall-mounted TVs, mobile-type computers, vehicle displays, mobile phones, and the like has been rapidly expanding. Accordingly, in order to thin the entire module of the liquid crystal display device, a thinner and lighter thin-film polarizing plate is required.

As a method of thinning a polarizing plate, the method of coating the adhesion layer, omitting the protective film which protects a polarizer is mainly proposed. However, when the protective film is omitted, there is a high probability that a problem occurs in the polarizer due to expansion and contraction occurring in harsh conditions than when the protective film is formed on both surfaces of the polarizer. International Publication No. 2009-145150 (hereinafter referred to as Patent Document 1) forms a protective layer having a tensile modulus of 100 MPa or more on one surface of a polarizer in which a protective film is omitted to physically suppress cracking of the polarizer. However, since the polarizing plate of Patent Document 1 has to form a separate UV cured layer, the process is increased, and it is difficult to select a material having excellent adhesion to the polarizer and release property to the base film at the same time, and is not partially coated. There is a problem.

The problem to be solved by the present invention is to provide a thin polarizing plate.

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

Another problem to be solved by the present invention is to provide a polarizing plate comprising an adhesive layer excellent in adhesion to the polarizer and to increase the crack resistance of the polarizer.

One embodiment of the present invention includes a polarizer, a protective film formed on one surface of the polarizer, and an adhesive layer formed on the other surface of the polarizer, wherein the adhesive layer comprises a (meth) acrylic copolymer and has a water vapor transmission rate of about 5 g / It relates to a polarizing plate, which is m ² / 24h or less.

Another embodiment of the present invention is a polarizing plate comprising a polarizer, a protective film formed on one side of the polarizer and an adhesive layer comprising a (meth) acrylic copolymer formed on the other side of the polarizer, glass on the back of the adhesive layer of the polarizing plate After laminating a substrate and applying a pressure of 4 kg, it is left for 500 hours at 85 ° C. and 1 hour at room temperature, and the polarization plate has a crack incidence of about 0%.

Another aspect of the present invention relates to an optical display device including the polarizing plate.

The polarizing plate of the present invention is excellent in durability at high temperature and high humidity, excellent adhesion to the polarizer and by forming an adhesive layer to increase the crack resistance of the polarizer, the protective film can be omitted, it is possible to thin the polarizing plate.

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 liquid crystal display according to an exemplary embodiment of the present invention.

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

Hereinafter, exemplary embodiments of the present application will be described in detail with reference to the accompanying drawings. However, the techniques disclosed in this application are 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 contents described in the specification may be thoroughly and completely, and to fully convey the spirit of the present application 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.

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 C1 to C10 alkyl group, hydroxyl group, amino group, C6 to C10 aryl group, halogen, cyano group, C3 to C10 cyclo It means an alkyl group, substituted with 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, the polarizing plate 100 according to an embodiment of the present invention may include a polarizer 110, a protective film 120 formed on one surface of the polarizer 110, and an adhesive layer formed on the other surface of the polarizer 110 ( 130).

The adhesive layer 130 includes a (meth) acrylic copolymer and has a water vapor transmission rate of about 5 g / m ² / 24h or less. When the moisture permeability of the adhesive layer 130 is greater than about 5 g / m ² / 24h, the durability at high temperature and high humidity conditions of the polarizing plate is reduced.

Specifically, the moisture permeability of the adhesive layer 130 may be about 4g / m ² / 24h or less and about 3g / m ² / 24h or less. In the above range, it is excellent in durability at high temperature and high humidity conditions of the polarizing plate, it is possible to provide a thin polarizing plate without requiring a separate protective film or barrier film.

In the present specification, the moisture permeability of the pressure-sensitive adhesive layer is laminated on a moisture-permeable cup in which 15 g of calcium chloride is added to a sample cut into a diameter of 60 mm according to JIS Z0208 after laminating an adhesive layer having a thickness of 20 μm and a TAC film having a thickness of 40 μm. The resultant was placed in a constant temperature and humidity chamber at 85 ° C. and a humidity of 85% RH, and left for 24 hours.

The polarizing plate 100 may have a thickness of about 200 μm or less. Specifically, the thickness of the polarizing plate 100 may be about 180 μm or less, more specifically about 130 μm or less, for example, about 30 μm to about 80 μm. Within this range, it is advantageous to provide a thinner and lighter thin-film polarizing plate.

The polarizing plate 100 may have a transmittance of about 90% or more, specifically about 90% to about 100% at a wavelength of 400 nm to 700 nm. In the above range, the polarizing plate is improved in optical properties, it may be advantageous to be used in the optical display device.

The polarizing plate 100 may have a polarization degree of about 90% or more, specifically about 90% to about 100%. In the above range, the polarizing plate is improved in optical properties, it may be advantageous to be used in the optical display device.

Hereinafter, the polarizer 110, the protective film 120, and the adhesive layer 130 included in the polarizing plate 100 according to the embodiments of the present invention will be described in detail.

The polarizer 110 is formed between the protective film 120 and the adhesive layer 130 to polarize the external light incident on the polarizer 100.

The polarizer 110 may be a polarizer made of a polyvinyl alcohol-based resin film. Specifically, the polarizer may be a polyvinyl alcohol polarizer or a polyene alcohol polarizer prepared by dehydrating a polyvinyl alcohol polarizer or a polyvinyl alcohol resin film in which at least one of iodine and dichroic dye is adsorbed onto the polyvinyl alcohol 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 about 100 mol%. Within this range, it is advantageous to manufacture a polarizer, and sufficient optical characteristics and durability can be ensured. 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 5,000. In the above range, it is advantageous to manufacture a polarizer, the polarizing plate can ensure sufficient optical characteristics and durability.

For example, 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, specifically about 3 to about 6, MD (machine direction) 1 It can be produced by axial 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. The polyene polarizer may be prepared by adding an acid catalyst to the polyvinyl alcohol resin film and dehydrating and drying. The acid catalyst may comprise an organic acid, an inorganic acid or mixtures thereof including aromatic sulfonic acids such as toluenesulfonic acid.

The polarizer 110 may have a thickness of about 50 μm or less, specifically about 30 μm or less, more specifically about 5 μm to about 30 μm, for example, about 10 μm to about 25 μm. Within this range, it is advantageous to provide a thinner and lighter thin-film polarizing plate.

The protective film 120 is formed on one surface of the polarizer 110 to protect the polarizer 110. In FIG. 1, the protective film 120 may be attached to one surface of the polarizer 110 by, for example, an optical adhesive layer (not shown).

A protective film 120 is the moisture permeability can be from about 30g / m ² / 24hr or less, specifically from about 5g / m ² / 24hr to about 20g / m ² / 24hr. In the above range, the protective film may increase the durability at high temperature and high humidity of the polarizing plate by blocking external moisture from penetrating into the polarizer.

The protective film 120 may have a front retardation (Ro) of about 5,000 nm or more, specifically about 5,000 nm to about 15,000 nm, and more specifically about 10,100 nm to about 12,000 nm at a wavelength of 550 nm. In the above range, it is possible to prevent the rainbow spots occur when using the polarizing plate.

The protective film 120 may have a biaxial degree (NZ) of about 1.8 or less, 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 1>

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

In Equation 1, nx, ny, and nz are refractive indexes in the x-axis, y-axis, and z-axis directions of the protective film at wavelengths of 550 nm, respectively.

The protective film 120 may have a thickness direction retardation (Rth) of Equation 2 below about 15,000 nm, specifically about 10,000 nm to about 12,000 nm at a wavelength of 550 nm. Rainbow stain removal effect due to birefringence may be excellent in the above range.

<Equation 2>

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

In Equation 2, nx, ny, and nz are refractive indexes in the x-axis, y-axis, and z-axis directions of the protective film at a wavelength of 550 nm, respectively, and d is a thickness (unit: nm) of the protective film.

The protective film 120 may have a value of at least one of the refractive index nx in the x-axis direction and the refractive index ny in the y-axis direction at a wavelength of 550 nm, and at the same time, the other value may be less than about 1.65. In this case, both the nx and ny may be less than about 1.65, or both nx and ny may be more excellent than the rainbow stain prevention effect compared to about 1.65 or more. 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 the rainbow stain prevention effect can be further improved.

In the present specification, "x-axis" means a slow axis, "y-axis" is a fast axis, the z-axis means a thickness, and the x-axis, y-axis, and z-axis orthogonal to each other with respect to the protective film or film.

The protective film 120 may be an optically transparent film formed of a polyester resin. Specifically, the polyester resin may include one or more of polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate and polybutylene naphthalate, but is not limited thereto.

As used herein, "optically transparent film" means that the transmittance is about 90% or more. Specifically, the protective film 120 may have a transmittance of about 90% to about 100%, more specifically about 98% to about 100%. In the above range, the polarizing plate is improved in optical properties, it may be advantageous to be used in the optical display device.

The protective film 120 may further provide a function to the polarizer by further including a functional coating layer on one surface of the protective film. Specifically, the functional coating layer may be one or more of a hard coating layer, an antireflection layer, an anti-fingerprint layer, an antistatic layer, a low reflection layer, 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 may provide an additional function to the polarizing plate without affecting the protective film, it may be advantageous to be used in the polarizing plate.

The protective film 120 may further include a primer layer on one surface of the polarizer attached thereto. In this case, the adhesive layer can be made to better adhere the polarizer and the protective film. 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. In the above range, the adhesion of the protective film to the polarizer may be increased and the total light transmittance may be increased.

The protective film 120 may have a thickness of about 5 μm to about 200 μm, specifically about 10 μm to about 150 μm, more specifically about 50 μm to about 100 μm, for example, about 20 μm to about 80 μm. Can be. Within this range, it is advantageous to provide a thinner and lighter thin-film polarizing plate, but it is possible to suppress the warpage of the polarizing plate together with the barrier layer.

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

The protective film composition including the polyester resin may further include a conventional additive in addition to the polyester resin. 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 phenolic, 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, thereby suppressing elution in the polyester film and suppressing the generation of holes in the film or the surface, thereby improving appearance. .

The TD draw ratio of the melt extruded resin film may be specifically about 3 times to about 8 times. In the draw ratio range, the protective film may further improve the rainbow stain reduction effect. At this time, the melt-extruded resin film may be stretched from about 1 to about 1.1 with MD. "MD stretching about 1 to about 1.1" means that there is no additional stretching except for mechanical stretching inevitably generated by moving the film to the MD by a roller or the like during 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 may be to stretch the resin film only in TD, but crystallize and stabilize the film by heat treatment. The heat treatment may be 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 by tension-relaxation may be about 0 times to about 3 times, specifically about 0.1 times to about 2 times, and more specifically about 0.1 times to about 1 times. In the temperature and draw ratio range, the retardation value of the protective film can be maintained and the crystallization effect and stabilization effect of the film can be further improved.

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

The adhesive layer 130 is formed on the other side of the polarizer 110, and protects the polarizer 110 from the opposite side to the protective film 120 with respect to the polarizer 110, and external moisture penetrates into the polarizer 110. By blocking the thing, durability at high temperature, high humidity of the polarizing plate 100 can be improved. The adhesive layer 130 may have high adhesion to the polarizer 110 and may be formed directly on the polarizer 110. In this case, thinning of the polarizing plate 100 is more advantageous.

The adhesive layer 130 may have a thickness of about 50 μm or less, specifically about 3 μm to about 30 μm, and more specifically about 5 μm to about 25 μm. In the above range, it is advantageous to be used for the polarizing plate, and can have an appropriate thickness ratio with respect to the protective film to suppress the warpage of the polarizing plate.

The thickness ratio (adhesive layer thickness: protective film thickness) of the protective film 120 to the adhesive layer 130 may be about 1: 0.1 to about 1:67. In this case, the protective film is advantageous to form a thin polarizing plate formed only on one surface of the polarizer. Specifically, the adhesive layer thickness: the protective film thickness is about 1: 0.3 to about 1:50, more specifically about 1: 1 to about 1:30, for example, about 1: 1 to about 1:10, about 1: 1 to about 1: 5, about 1: 1 to about 1: 4. In the above range, the protective film is formed on one surface of the polarizer, the curvature suppression effect in the case where the adhesive layer is formed on the other surface can be further improved.

The adhesive layer 130 may be a cured product of an adhesive composition including a (meth) acrylic copolymer. Hereinafter, the adhesive composition will be described.

The pressure-sensitive adhesive composition according to an embodiment of the present invention may include a (meth) acrylic copolymer.

The (meth) acrylic copolymer has a (meth) acrylate monomer (a1) having an alkyl group of 11 to 20 carbon atoms, a hydroxyl group-containing (meth) acrylate monomer (a2), and a glass transition temperature (Tg) of about -150 ° C. It can be prepared by copolymerizing a monomer mixture comprising a monomer (a3) to about 0 ℃.

The (meth) acrylate monomer (a1) having an alkyl group having 11 to 20 carbon atoms may be a substituted or unsubstituted compound. Specifically, the (meth) acrylate monomer (a1) having an alkyl group having 11 to 20 carbon atoms is undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) Acrylate, pentadecyl (meth) acrylate, palmityl (meth) acrylate, heptadecyl (meth) acrylate oleyl (meth) acrylate, stearyl (meth) acrylate, isosil (meth) acrylate, etc. Can be.

In one embodiment, the (meth) acrylate monomer (a1) having an alkyl group of 11 to 20 carbon atoms is dodecyl (meth) acrylate, tetradecyl (meth) acrylate, oleyl (meth) acrylate, palmityl ( One or more of meth) acrylate and stearyl (meth) acrylate can be used. In this case, the barrier property to air and water vapor can be improved to lower the moisture permeability.

The (meth) acrylate monomer having an alkyl group having 11 to 20 carbon atoms may be about 5% by weight or more, specifically about 5% by weight to about 45% by weight, more specifically about 5% by weight to about the total weight of the monomer mixture. 35 weight percent, such as about 5 weight percent to about 30 weight percent or about 10 weight percent to about 20 weight percent. In the above range, the adhesive layer has sufficient adhesion durability and moisture permeation inhibitory effect.

The hydroxyl group-containing (meth) acrylate monomer (a2) may be a (meth) acrylate monomer containing at least one hydroxyl group and a hydrocarbon group having 1 to 20 carbon atoms. The hydrocarbon group having 1 to 20 carbon atoms may be, for example, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

Specifically, the hydroxyl group-containing (meth) acrylate monomer (a2) is 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4- 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, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, neopentylglycol mono (meth ) Acrylate, trimethylolpropane di (meth) acrylate, trimethylolethane di (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, 4-hydroxycyclopentyl (meth) acrylic Latex, 4-hydroxycyclo Of the chamber (meth) acrylate and cyclohexanedimethanol mono (meth) acrylate may be at least one.

In one embodiment, by using an alkyl group-containing (meth) acrylic monomer having a hydroxyl group containing 1 to 5 carbon atoms it is possible to implement a more excellent adhesive force synergistic effect.

In another embodiment, the hydroxyl group-containing (meth) acrylate monomer (a2) is 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, One or more of 4-hydroxybutyl (meth) acrylate and 6-hydroxyhexyl (meth) acrylate can be used. In this case, not only productivity is improved when the pressure-sensitive adhesive layer is manufactured, but also the adhesive force of the pressure-sensitive adhesive can be further improved.

The hydroxyl group-containing (meth) acrylate monomer (a2) may be included in about 0.5% to about 5% by weight relative to the total weight of the monomer mixture, it may be more excellent in adhesion and reliability in the above range.

The monomer (a3) having a glass transition temperature (Tg) of about -150 ° C to about 0 ° C can be used without limitation as long as it has a glass transition temperature (Tg) of about -150 ° C to about 0 ° C. Specifically, a monomer having a glass transition temperature (Tg) of about -150 ° C to about -20 ° C, for example, a monomer having a glass transition temperature (Tg) of about -150 ° C to about -40 ° C can be used.

In the present specification, the glass transition temperature can be measured using, for example, DSC Q20 manufactured by TA Instrument for the homopolymer of each monomer to be measured. Specifically, after raising the temperature to 160 ° C at a rate of 20 ° C / min with respect to the homopolymer of each monomer, the mixture is gradually cooled to maintain an equilibrium at 50 ° C and heated up to 160 ° C at a rate of 10 ° C / min. After the endothermic transition curve data is obtained, the inflection point of the endothermic transition curve is determined as the glass transition temperature.

Specifically, the monomer (a3) having a glass transition temperature (Tg) of about -150 ° C to about 0 ° C may be an alkyl (meth) acrylate monomer (a31) having 1 to 10 carbon atoms, a monomer (a32) having ethylene oxide, or propylene. Monomer (a33) having an oxide, monomer (a34) having an amine group, monomer (a35) having an amide group, monomer (a36) having an alkoxy group, monomer (a37) having a phosphoric acid group, monomer (a38) having a sulfonic acid group, phenyl group The glass transition temperature (Tg) of the monomer (a39) and the monomer (a40) having a silane group may include at least about -150 ℃ to about 0 ℃.

The alkyl (meth) acrylate monomer (a31) having 1 to 10 carbon atoms may specifically include an unsubstituted linear or branched alkyl (meth) acrylic acid ester having 1 to 10 carbon atoms. For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, iso-butyl (meth) acrylic Latex, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) And at least one of acrylate and decyl (meth) acrylate.

Preferably, the use of an alkyl (meth) acrylic monomer having 4 to 8 carbon atoms may further increase the initial adhesive force.

In one embodiment, the alkyl (meth) acrylate monomer (a31) having a glass transition temperature (Tg) of about -150 ° C to about 0 ° C includes ethyl acrylate, isotactic iso-propyl acrylate, n-butyl acrylate, sec-butyl acrylate, iso-butyl acrylate, 2-ethylhexyl (meth) acrylate, hexyl methacrylate, and the like can be used.

As the monomer (a32) having ethylene oxide, one or more (meth) acrylate monomers containing an ethylene oxide group (-CH ₂ CH ₂ O-) can be used. For example, polyethylene oxide monomethyl ether (meth) acrylate, polyethylene oxide monoethyl ether (meth) acrylate, polyethylene oxide monopropyl ether (meth) acrylate, polyethylene oxide monobutyl ether (meth) acrylate, polyethylene oxide mono Pentyl ether (meth) acrylate, polyethylene oxide dimethyl ether (meth) acrylate, polyethylene oxide diethyl ether (meth) acrylate, polyethylene oxide monoisopropyl ether (meth) acrylate, polyethylene oxide monoisobutyl ether (meth) Polyethylene oxide alkyl ether (meth) acrylates such as acrylate and polyethylene oxide monotertbutyl ether (meth) acrylate.

Monomer (a33) having propylene oxide is, for example, polypropylene oxide monomethyl ether (meth) acrylate, polypropylene oxide monoethyl ether (meth) acrylate, polypropylene oxide monopropyl ether (meth) acrylate, poly Propylene oxide monobutyl ether (meth) acrylate, polypropylene oxide monopentyl ether (meth) acrylate, polypropylene oxide dimethyl ether (meth) acrylate, polypropylene oxide diethyl ether (meth) acrylate, polypropylene oxide mono Polypropylene oxide alkyl ether (meth) acrylates such as isopropyl ether (meth) acrylate, polypropylene oxide monoisobutyl ether (meth) acrylate, and polypropylene oxide monotertbutyl ether (meth) acrylate. have.

Monomer (a34) which has an amine group is monomethylaminoethyl (meth) acrylate, monoethylaminoethyl (meth) acrylate, monomethylaminopropyl (meth) acrylate, monoethylaminopropyl (meth) acryl, for example. Such as the rate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, N-tert-butylaminoethyl (meth) acrylate, and methacryloxyethyltrimethylammonium chloride (meth) acrylate It may be an amine group-containing (meth) acrylic monomer.

The monomer (a35) having an amide group is, for example, (meth) acrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acryl Amide group-containing (meth) acrylic monomers such as amide, N, N-methylene bis (meth) acrylamide, 2-hydroxyethylacrylamide, and the like. The monomer (a36) having an alkoxy group may be, for example, 2- Methoxy ethyl (meth) acrylate, 2-ethoxy ethyl (meth) acrylate, 2-methoxypropyl (meth) acrylate, 2-ethoxypropyl (meth) acrylate, 2-butoxypropyl (meth) Acrylate, 2-methoxypentyl (meth) acrylate, 2-ethoxypentyl (meth) acrylate, 2-butoxyhexyl (meth) acrylate, 3-methoxypentyl (meth) acrylate, 3-in To be methoxypentyl (meth) acrylate, 3-butoxyhexyl (meth) acrylate Can be.

In one embodiment, 2-ethoxyethyl acrylate, 2-methoxyethyl acrylate, or the like may be used as the monomer (a36) having an alkoxy group.

Monomer (a37) which has a phosphoric acid group is 2-methacryloyloxyethyl diphenyl phosphate (meth) acrylate, trimethacryloyloxyethyl phosphate (meth) acrylate, triacryloyloxyethyl phosphate, for example. It may be an acrylic monomer having a phosphoric acid group such as (meth) acrylate.

The monomer (a38) having a sulfonic acid group is, for example, sulfones such as sodium sulfopropyl (meth) acrylate, sodium 2-sulfoethyl (meth) acrylate, and sodium 2-acrylamido-2-methylpropane sulfonate. It may be an acrylic monomer having an acid group.

The monomer (a39) having a phenyl group may be, for example, an acrylic vinyl monomer having a phenyl group such as p-tert-butylphenyl (meth) acrylate and o-biphenyl (meth) acrylate.

The monomer (a40) having a silane group may be, for example, 2-acetoacetoxyethyl (meth) acrylate, vinyltrimethoxysilane, vinyltriethoxysilane, vinyl tris (β-methoxyethyl) silane, or vinyltriacetyl. And vinyl monomers having a silane group such as silane and methacryloyloxypropyltrimethoxysilane.

The monomer having a glass transition temperature (Tg) of about -150 ° C to about 0 ° C is about 50% to about 94.5% by weight, specifically about 50% to about 90% by weight, based on the total weight of the monomer mixture, for example And about 50% to about 80% by weight. Excellent adhesion and reliability in the above range can be more excellent.

In one embodiment, the weight ratio of the above-mentioned (meth) acrylate monomer (a1) having an alkyl group of 11 to 20 carbon atoms and monomer (a3) having a glass transition temperature (Tg) of about -150 ° C to about 0 ° C is about 1 From 1: 1 to about 1:18. Within this range, the moisture permeability and adhesion characteristics can be compatible. Specifically, the weight ratio of a1: a3 may be about 1: 1.1 to about 1:15, about 1: 1.2 to about 1:10, about 1: 1.4 to about 1: 8. Within this range, the adhesive property can be further improved and the optical property can be excellent.

The (meth) acrylic copolymer has a (meth) acrylate monomer (a1) having an alkyl group of 11 to 20 carbon atoms, a hydroxyl group-containing (meth) acrylate monomer (a2), and a glass transition temperature (Tg) of about -150 ° C. It can be prepared by copolymerizing a monomer mixture comprising a monomer (a3) to about 0 ° C, further comprising a (meth) acrylic acid monomer (a4). In this case, it is possible to implement a more excellent adhesive force synergistic effect.

 The (meth) acrylic acid monomer (a4) may contain about 0.5 wt% to about 10 wt% of the hydroxyl group-containing (meth) acrylate monomer (a2) based on the total weight of the monomer mixture. Excellent adhesion and reliability in the above range can be more excellent.

 The (meth) acrylic acid monomer (a4) may be, for example, an acrylic acid monomer, a methacrylic acid monomer or a mixture thereof. In this case, the degree of crosslinking can be further improved during the preparation of the (meth) acrylic copolymer.

The adhesive layer of one embodiment may further include a crosslinking agent.

The crosslinking agent may be a multifunctional crosslinking agent. Such a multifunctional crosslinking agent may specifically include one or more selected from the group consisting of a multifunctional (meth) acrylate crosslinking agent, an isocyanate crosslinking agent and an epoxy crosslinking agent.

More specifically, as a multifunctional (meth) acrylate type crosslinking agent, it is 1, 4- butanediol di (meth) acrylate, 1, 6- hexanediol di (meth) acrylate, neopentylglycol di (meth), for example. Acrylate, polyethylene glycol di (meth) acrylate, neopentylglycol adipate di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di ( Meth) acrylate, ethylene oxide modified di (meth) acrylate, di (meth) acryloxyethyl isocyanurate, allylated cyclohexyl di (meth) acrylate, tricyclodecanedimethanol (meth) acrylate, Dimethylol dicyclopentane di (meth) acrylate, ethylene oxide modified hexahydrophthalic acid di (meth) acrylate, tricyclodecane dimethanol (meth) acrylate, neopentyl Bifunctional such as recall modified trimethylpropane di (meth) acrylate, adamantane di (meth) acrylate or 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene Sex acrylates; Trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide Trifunctional acrylates such as modified trimethylolpropane tri (meth) acrylate, trifunctional urethane (meth) acrylate or tris (meth) acryloxyethyl isocyanurate; Tetrafunctional acrylates such as diglycerin tetra (meth) acrylate or pentaerythritol tetra (meth) acrylate; 5-functional acrylates, such as dipentaerythritol penta (meth) acrylate; And difunctional acrylates such as dipentaerythritol hexa (meth) acrylate and caprolactone-modified dipentaerythritol hexa (meth) acrylate, and the like, but are not limited thereto. These can be used individually or in mixture of 2 or more types. For example, the crosslinking agent can be implemented in a more excellent range of durability by using a polyfunctional (meth) acrylate of a polyhydric alcohol having about 2 to 20 hydroxyl groups.

More specifically, isocyanate compounds are compounds having at least two isocyanate groups (-NCO) in the molecule, for example tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated x Silylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, etc. are mentioned. Moreover, the adduct body which made these polyisocyanate compounds react polyols, such as glycerol and a trimetholpropane, and also made the isocyanate compound into dimer, trimer, etc. can also be a crosslinking agent used for an adhesive. Two or more types of isocyanate compounds in the above examples may be mixed and used.

More specifically, the epoxy crosslinking agent is a compound having at least two epoxy groups in the molecule, and for example, bisphenol A type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl Ether, glycerin triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimetholpropane triglycidyl ether, N, N- diglycidyl aniline, N, N, N ', N'-tetra Glycidyl-m-xylenediamine, 1,3-bis (N, N'- diglycidylaminomethyl) cyclohexane, etc. are mentioned. Two or more types of epoxy-type compounds in the said example can also be mixed and used.

A crosslinking agent can mix and use 2 or more types of a polyfunctional (meth) acrylate type crosslinking agent, an isocyanate type crosslinking agent, and an epoxy type crosslinking agent. In such a case, the adhesive force of the adhesive composition can be further improved.

The crosslinking agent may be included in an amount of about 0.01 to about 20 parts by weight, specifically about 0.5 to about 2.0 parts by weight, specifically about 1.0 to about 16.0 parts by weight, based on 100 parts by weight of the (meth) acrylic copolymer. Within this range, the adhesion and reliability of the pressure-sensitive adhesive layer can be further improved.

In one embodiment, the crosslinking agent may be used by mixing an isocyanate crosslinking agent and an epoxy crosslinking agent. In this case, the weight ratio of isocyanate-based crosslinking agent to isocyanate-based (isocyanate crosslinking agent: epoxy clock crosslinking agent) may be about 2: 1 to about 100: 1, and specifically about 4: 1 to about 50: 1. . Within this range, the adhesion and reliability of the pressure-sensitive adhesive layer can be further improved.

In another embodiment, by using a large amount of isocyanate-based crosslinking agent, it is possible to prevent air bubbles or polarizer cracks at the interface between the polarizer and the adhesive layer by lowering the permeation amount of air and water vapor by crosslinking the acrylic copolymer.

The pressure-sensitive adhesive composition may further include the aforementioned crosslinking agent or silane coupling agent.

The silane coupling agent may further include a siloxane-based or epoxy-based silane coupling agent, but is not limited thereto. The silane coupling agent may be included in an amount of about 0.01 parts by weight to about 0.1 parts by weight, specifically about 0.05 parts by weight to about 0.1 parts by weight, based on 100 parts by weight of the (meth) acrylic copolymer. There is an effect of increasing the reliability in the above range.

The adhesive composition may further include hygroscopic fine particles in order to suppress moisture permeability as much as possible.

The hygroscopic microparticles may include, but are not limited to, one or more of clay, silica, aluminum oxide, zirconium oxide, and titanium oxide. The fine particles may be surface treated with an epoxy group, a (meth) acrylate group or a vinyl group to increase compatibility. The fine particles are not limited in shape and size. Specifically, the fine particles may include particles having a spherical shape, a plate shape, an amorphous shape, and the like. The fine particles may have an average particle diameter of about 1 nm to about 200 nm, specifically about 10 nm to about 50 nm. Within this range, the hardness of the barrier layer can be increased without affecting the surface roughness and transparency of the barrier layer.

Hygroscopic microparticles | fine-particles are about 0.1 weight%-about 10 in a solid adhesion layer Weight percent, specifically about 1 wt% to about 10 wt%, more specifically about 1 wt% to about 5 wt%. Within this range, the moisture resistance can be further improved without affecting the surface roughness and transparency of the pressure-sensitive adhesive layer.

The pressure-sensitive adhesive composition may further include an additive. Additives include curing accelerators, ionic liquids, lithium salts, inorganic fillers, softeners, molecular weight regulators, antioxidants, antioxidants, stabilizers, tackifying resins, modified resins (polyol resins, phenolic resins, acrylic resins, polyester resins, polyolefin resins). , Epoxy resins, epoxidized polybutadiene resins, etc.), leveling agents, antifoaming agents, plasticizers, dyes, pigments (colored pigments, sieving pigments, etc.), treatment agents, sunscreen agents, optical brighteners, dispersants, thermal stabilizers, light stabilizers, It may be conventional additives such as ultraviolet absorbers, antistatic agents, flocculants, lubricants and solvents.

The adhesive composition may have a viscosity of about 100 cP to about 6,000 cP, specifically about 1000 cP to about 5500 cP, more specifically about 2000 cP to about 4500 cP, for example, about 3000 cP to about 4500 cP at 25 ° C. In the above range, the formation of the adhesive layer may be easier.

Another embodiment of the present invention includes a pressure-sensitive adhesive layer comprising a polarizer, a protective film formed on one side of the polarizer and a (meth) acrylic copolymer formed on the other side of the polarizer, and a glass substrate on the back of the pressure-sensitive adhesive layer of the polarizing plate After laminating and applying a pressure of 4 kg, it is left for 500 hours at 85 ° C. and 1 hour at room temperature, and the polarization plate has a crack incidence of about 0%.

Specifically, the pressure-sensitive adhesive layer may include a (meth) acrylic copolymer and have a water vapor transmission rate of about 5 g / m ² / 24h or less. Details of the adhesive layer are the same as described above.

In addition, another embodiment of the present invention relates to an optical display device including a polarizing plate according to the embodiments of the present invention described above.

Hereinafter, an optical display device according to an exemplary embodiment of the present invention will be described with reference to FIG. 2. 2 is a cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.

2, the liquid crystal display device 200 according to an exemplary embodiment of the present invention includes a liquid crystal panel 210, a first polarizing plate 220 formed on one surface of the liquid crystal panel 210, and another surface of the liquid crystal panel 210. A second polarizing plate 230 formed in the, and a backlight unit 240 located on the lower surface of the second polarizing plate 230, the first polarizing plate 220 may include a polarizing plate according to embodiments of the present invention have.

The liquid crystal panel 210 may be formed between the first polarizing plate 220 and the second polarizing plate 230 to transmit light incident from the second polarizing plate to the first polarizing plate 220. The liquid crystal panel 210 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 230 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 240 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, It may be a film containing at least one of polyacrylate resin, polyaryl sulfone resin, polyether sulfone resin, polyphenylene sulfide resin, fluorine resin and (meth) acrylic resin.

The backlight unit 240 may include a light guide plate, a light source, a reflective sheet, a diffusion sheet, and the like.

FIG. 2 illustrates a case where the first polarizing plate 220 is a polarizing plate according to embodiments of the present invention. However, the case where the second polarizing plate 230 is a polarizing plate according to embodiments of the present invention and the first polarizing plate 210 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 220 and the second polarizing plate 230 are polarizing plates according to embodiments of the present invention may also be included in the scope of the present invention.

3 is a cross-sectional view of a liquid crystal display device 300 according to another embodiment of the present invention. Specifically, the first polarizing plate 220 and the second polarizing plate 230 are both polarizing plates according to embodiments of the present invention. It is shown.

Referring to FIG. 3, in the first polarizing plate 220, the first protective film 222, the first polarizer 221, and the first adhesive layer 223 are sequentially stacked, and the first adhesive layer 223 is It may be formed directly on the liquid crystal panel 210.

In the second polarizing plate 230, the second protective film 232, the second polarizer 231, and the second adhesive layer 233 are sequentially stacked, and the second adhesive layer 223 is directly formed on the liquid crystal panel 210. It may be formed directly below.

As such, since the first adhesive layer 223 and the second adhesive layer 223 having low moisture permeability and excellent high temperature and high humidity durability are provided, a barrier film or a protective film may be omitted to provide a thinner polarizing plate.

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.

Example

(1) polarizer manufacturing

A polyvinyl alcohol film (saponification degree: 99.5 mol%, polymerization degree: 2000, thickness: 80 mu m) was dyed by immersion in 0.3% iodine aqueous solution. MD uniaxial stretching was carried out with 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 Adhesive Composition

Preparation Example 1:

50 g of ethyl acetate, 10 g of methyl ethyl ketone, 76 g of n-butyl acrylate (Tg: -54 ° C.), 20 g of dodecyl acrylate, 2 g of 2-hydroxyethyl methacrylate and 2 g of acrylic acid were added to a 1 L four-neck flask. The temperature was raised and maintained at ℃. 0.06 g of initiator azobisisobutyronitrile was dissolved in 20 g of ethyl acetate and charged. After reacting at 65 ° C. for 3 hours, 170 g of methyl ethyl ketone was added and cooled to 40 ° C. to prepare a first (meth) acrylic copolymer having a viscosity of 4,500 cP.

Epoxy crosslinking agent (TETRAD-C, Mitsubishi Gas Chemical Co. ) 0.3 g, silane coupling agent 3-glyoxy propyl methoxy silane (KBM-403, Shin-Yestsu) 1.0g was mixed and stirred for 30 minutes at 25 ℃ to prepare a pressure-sensitive adhesive composition.

Preparation Example 2:

50 g of ethyl acetate, 10 g of methyl ethyl ketone, 76 g of n-butyl acrylate, 10 g of stearyl acrylate, 2 g of 2-hydroxyethyl methacrylate and 2 g of acrylic acid were added to a 1 L four-neck flask, and the temperature was maintained at 70 ° C. 0.06 g of initiator azobisisobutyronitrile was dissolved in 20 g of ethyl acetate and charged. After reacting at 65 ° C. for 3 hours, 170 g of methyl ethyl ketone was added and cooled to 40 ° C. to obtain a second viscosity of 4,300 cP. A (meth) acrylic copolymer was prepared.

A pressure-sensitive adhesive composition was prepared in the same manner as in Preparation Example 1, except that the first crosslinking agent, the second crosslinking agent, and the silane coupling agent were added to the prepared second (meth) acrylic copolymer in the amounts shown in Table 1 below. .

Preparation Example 3:

A pressure-sensitive adhesive composition was prepared in the same manner as in Preparation Example 1, except that the first crosslinking agent, the second crosslinking agent, and the silane coupling agent were added to the prepared first (meth) acrylic copolymer in the amounts shown in Table 1 below. .

Preparation Example 4:

A pressure-sensitive adhesive composition was prepared in the same manner as in Preparation Example 1, except that the first crosslinking agent, the second crosslinking agent, and the silane coupling agent were added to the prepared second (meth) acrylic copolymer in the amounts shown in Table 1 below. .

Preparation Example 5:

A first crosslinking agent, a second crosslinking agent, and a silane coupling agent were added to the prepared first (meth) acrylic copolymer in the amounts shown in Table 1 below, and 10 g of acrylic modified nanoclay (Closite20A, Southern Clay) was further added as hygroscopic microparticles. A polarizing plate was manufactured in the same manner as in Example 1, except that was added.

Preparation Example 6:

50 g of ethyl acetate, 10 g of methyl ethyl ketone, 96 g of n-butyl acrylate, 2 g of 2-hydroxyethyl methacrylate and 2 g of acrylic acid were added to a 1 L four-neck flask, and the temperature was maintained at 70 ° C. 0.06 g of initiator azobisisobutyronitrile was dissolved in 20 g of ethyl acetate and charged. After reacting at 65 ° C. for 3 hours, 170 g of methyl ethyl ketone was added and cooled to 40 ° C. to prepare a third (meth) acrylic copolymer having a viscosity of 4,400 cP.

A pressure-sensitive adhesive composition was prepared in the same manner as in Preparation Example 1, except that a first crosslinking agent, a second crosslinking agent, and a silane coupling agent were added to the third (meth) acrylic copolymer prepared in the amount shown in Table 1 below. .

	ingredient	Preparation Example 1	Preparation Example 2	Preparation Example 3	Preparation Example 4	Preparation Example 5	Preparation Example 6
Composition of Adhesive Composition	First (meth) acrylic copolymer	100	-	100	-	100	-
	Second (meth) acrylic copolymer	-	100	-	100	-	-
	Third (meth) acrylic copolymer	-	-	-	-	-	100
	First crosslinking agent	1.2	1.2	15	15	1.2	1.2
	Second crosslinking agent	0.3	0.3	0.3	0.3	0.3	0.3
	Silane coupling agent	1.0	1.0	1.0	1.0	1.0	1.0
	Hygroscopic particulates	-	-	-	-	10	-

Example

Example 1

On one side of the polarizer, a protective film (polyethylene terephthalate film, water transmittance: 10g / m ² / 24hr, Ro: 10,000nm at a wavelength of 550nm, thickness: 80㎛, manufactured by Toyobo Co., Ltd.) an epoxy adhesive (adeka) It was laminated by using. After lamination, ultraviolet irradiation was performed at 400 mW / cm ² and 1000 mJ / cm ² with a metal halide lamp.

After applying the pressure-sensitive adhesive composition of Preparation Example 1 on the other side of the polarizer and dried for 3 minutes at 100 ° C to form a pressure-sensitive adhesive layer for a polarizing plate to a thickness of 20㎛ protective film (thickness: 80㎛), polarizer (thickness: 23 micrometers) and the polarizing plate in which the adhesion layer (thickness: 20 micrometers) were formed one by one were manufactured. The physical properties were measured based on the following physical property evaluation method, and the results are shown in Table 2 below.

Example  2 to 5 and Comparative example  One

A polarizing plate was manufactured in the same manner as in Example 1, except that the composition of the adhesive composition was as shown in Table 1 below.

Property evaluation method

(1) Water vapor permeability of the pressure-sensitive adhesive layer: The water vapor permeability of the pressure-sensitive adhesive layer was measured based on JIS Z0208 for a sample in which a pressure-sensitive adhesive layer having a thickness of 20 μm and a TAC film having a thickness of 40 μm formed from the pressure-sensitive adhesive compositions of Preparation Examples 1 to 6 were laminated. It was. Specifically, a sample cut to a diameter of 60 mm was placed in a moisture cup containing 15 g of calcium chloride, and placed in a constant temperature / humidity chamber having a temperature of 85 ° C. and a humidity of 85% RH, and left for 24 hours to measure the weight of the increased calcium chloride. According to 3, the water vapor transmission rate of the adhesion layer was evaluated.

<Equation 3>

Water vapor transmission rate of the adhesive layer = (TAC water vapor transmission rate)-(sample water vapor transmission rate)

(2) High Temperature Durability (85 ° C.): After cutting the polarizing plates prepared in Examples 1 to 5 and Comparative Example 1 to 100 mm x 175 mm, laminating the glass substrate on the back side of the adhesive layer and applying a 4 kg pressure Was produced. In order to determine the heat resistance characteristics of the specimens, the specimens were left for 500 hours at 85 ° C. and observed for appearance abnormalities such as bubbles / floating of the adhesive layer. After standing for 1 hour at room temperature was observed by visual or microscope. When cracks occur ○ When no crack occurs, it is indicated by Ⅹ (0% crack occurrence rate).

(3) High temperature / high humidity durability (85 ° C./85 RH%): After cutting the polarizing plates prepared in Examples 1 to 5 and Comparative Example 1 to 100 mm x 175 mm and laminating the glass substrate on the back of the adhesive layer 4 kg The specimen was prepared by applying a pressure of. In order to determine the heat and moisture resistance of the specimens, the specimens were left for 500 hours at 85 ° C./85% relative humidity and observed for cracks on the surface of the adhesive layer. After standing for 1 hour at room temperature was observed by visual or microscope. When cracks occur ○ When no crack occurs, it is indicated by Ⅹ (0% crack occurrence rate).

		Example 1	Example 2	Example 3	Example 4	Example 5	Comparative Example 1
Adhesive composition		Preparation Example 1	Preparation Example 2	Preparation Example 3	Preparation Example 4	Preparation Example 5	Preparation Example 6
Polarizer Structure		Protective film / polarizer / adhesive layer	Protective film / polarizer / adhesive layer	Protective film / polarizer / adhesive layer	Protective film / polarizer / adhesive layer	Protective film / polarizer / adhesive layer	Protective film / polarizer / adhesive layer
Adhesive layer moisture permeability (g / m 2 / 24h)		4.7	4.3	3.8	3.4	2.3	7.5
durability	Bubble / floating presence of adhesive layer	X	X	X	X	X	X
	85 ℃ Crack	X	X	X	X	X	X
	85 ℃ / 85% Crack	X	X	X	X	X	O

As shown in Table 2, the polarizing plate according to the embodiments of the present invention did not generate bubbles and lifting of the adhesive layer, it was found that the durability of the polarizer does not occur even at high temperature and high humidity.

On the other hand, the pressure-sensitive adhesive layer of Comparative Example 1 made of a third (meth) acrylic copolymer resin that does not use a (meth) acrylate monomer having an alkyl group having 11 to 20 carbon atoms has a high moisture permeability of Comparative Example 1 It was found that the polarizing plate had low durability due to cracking of the polarizer in a high temperature and high humidity environment.

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 (17)

1. Polarizer; A protective film formed on one surface of the polarizer; And an adhesive layer formed on the other surface of the polarizer. Including,

   The adhesive layer includes a (meth) acrylic copolymer and a moisture permeability of about 5 g / m ² / 24h or less.
2. The method of claim 1,

   The (meth) acrylic copolymer is a copolymer of a monomer mixture containing a (meth) acrylate monomer having an alkyl group having 11 to 20 carbon atoms.
3. The method of claim 1,

   The (meth) acrylic copolymer has a (meth) acrylate monomer (a1) having an alkyl group of 11 to 20 carbon atoms, a hydroxyl group-containing (meth) acrylate monomer (a2), and a glass transition temperature (Tg) of about -150 ° C. And a copolymer of a monomer mixture comprising a monomer (a3) that is from about 0 ° C.
4. The method of claim 3,

   The monomer mixture is about 5% to about 45% by weight of the (meth) acrylate monomer (a1) having an alkyl group of 11 to 20 carbon atoms, about 0.5% to about 5% by weight of the hydroxyl group-containing (meth) acrylate monomer (a2) %, And about 50% to about 90% by weight of monomer (a3) having a glass transition temperature (Tg) of about -150 ° C to about 0 ° C.
5. The method of claim 3,

   The monomer mixture further comprises a (meth) acrylic acid monomer (a4).
6. The method of claim 1,

   The pressure-sensitive adhesive layer further comprises at least one crosslinking agent selected from the group consisting of a polyfunctional (meth) acrylate crosslinking agent, an isocyanate crosslinking agent and an epoxy crosslinking agent.
7. The method of claim 6,

   The crosslinking agent is included in about 0.01 parts by weight to about 20 parts by weight based on 100 parts by weight of the (meth) acrylic copolymer.
8. The method of claim 6,

   And the crosslinking agent comprises an isocyanate crosslinking agent and an epoxy crosslinking agent, wherein a weight ratio of the isocyanate crosslinking agent and the epoxy crosslinking agent is about 2: 1 to about 100: 1.
9. The method of claim 1,

   The adhesive layer further includes hygroscopic microparticles having an average particle diameter of about 1 nm to about 200 nm,

   The hygroscopic microparticles may include at least one of clay, silica, aluminum oxide, zirconium oxide and titanium oxide.
10. The method of claim 9,

    The hygroscopic microparticles are included in about 0.1% to about 10% by weight of the adhesive layer.
11. The method of claim 9,

    The adhesive layer has a moisture permeability of about 3g / m ² / 24h or less polarizing plate.
12. The method of claim 1,

    The protective film is a polarizing plate, characterized in that the front retardation (Ro) is about 5,000nm to about 15,000nm at a wavelength of 550nm.
13. The method of claim 1,

    The protective film is a polarizing plate, characterized in that any one of the value of the refractive index nx in the x-axis direction and the refractive index ny in the y-axis direction at a wavelength of 550nm is about 1.65 or more, and at the same time the other value is less than about 1.65.
14. The method of claim 1,

    The polarizing plate has a thickness of about 200㎛ or less.
15. A polarizer including a polarizer, a protective film formed on one surface of the polarizer, and an adhesive layer including a (meth) acrylic copolymer formed on the other surface of the polarizer,

    After laminating a glass substrate on the back of the adhesive layer of the polarizing plate and applying a pressure of 4 kg, the polarizing plate has a crack incidence of about 0% after being left at 85 ° C. for 500 hours and at room temperature for 1 hour.
16. The method of claim 15,

    The adhesive layer has a moisture permeability of about 5g / m ² / 24h or less polarizing plate.
17. An optical display device comprising the polarizing plate of claim 1.

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