KR20160127224A - Polarizing plate and optical display apparatus comprising the same - Google Patents

Polarizing plate and optical display apparatus comprising the same Download PDF

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Publication number
KR20160127224A
KR20160127224A KR1020150057555A KR20150057555A KR20160127224A KR 20160127224 A KR20160127224 A KR 20160127224A KR 1020150057555 A KR1020150057555 A KR 1020150057555A KR 20150057555 A KR20150057555 A KR 20150057555A KR 20160127224 A KR20160127224 A KR 20160127224A
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South Korea
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meth
polarizer
acrylate
adhesive layer
monomer
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KR1020150057555A
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Korean (ko)
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KR101854498B1 (en
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김원
유미연
윤동헌
이승훈
정은환
한인천
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삼성에스디아이 주식회사
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Priority to KR1020150057555A priority Critical patent/KR101854498B1/en
Priority to PCT/KR2016/002210 priority patent/WO2016171389A1/en
Publication of KR20160127224A publication Critical patent/KR20160127224A/en
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133528—Polarisers

Abstract

The present invention provides a polarizer comprising 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 moisture permeability of 5 g / m 2 / And a polarizing plate. The polarizing plate is excellent in durability at high temperature and high humidity, has excellent adhesion to a polarizer, and can form a pressure-sensitive adhesive layer for enhancing crack resistance of the polarizer, so that a protective film can be omitted.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing plate and an optical display device including the polarizing plate.

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

The liquid crystal display includes a liquid crystal panel and a polarizing plate formed on both sides of the liquid crystal panel. The polarizing plate includes a polarizer and a protective film formed on both sides of the polarizer.

The polarizer includes an iodine compound or a dichroic polarizing material arranged in a predetermined direction. In order to protect the polarizer, a protective film such as triacetyl cellulose (TAC) is used on both sides of the polarizer to constitute a plurality of layers do. The polarizing plate may additionally include an optical film such as a retardation film or a liquid crystal type film.

Recently, the market for a thin film type liquid crystal display device such as a slim large wall-mounted TV, a mobile type computer, a car display, and a mobile phone has been rapidly expanding. Accordingly, there is a demand for a thin film type polarizing plate which is made thin and light in order to thin the entire module of the liquid crystal display device.

As a method of thinning the polarizing plate, a method of coating a pressure-sensitive adhesive layer by omitting a protective film for protecting the polarizer has been mainly proposed. However, when the protective film is omitted, there is a high probability that cracks will occur in the polarizing element due to expansion and contraction occurring under harsh conditions in a case where a protective film is formed on both sides of the polarizer. International Publication No. 2009-145150 (hereinafter referred to as Patent Document 1) physically suppresses the occurrence of cracks in a polarizer by forming a protective layer having a tensile modulus of 100 MPa or more on one surface of a polarizer having a protective film omitted. However, since the polarizing plate of Patent Document 1 requires an additional UV-cured layer to be formed, it is difficult to select a material having excellent adhesion to a polarizing element and releasability to a base film at the same time, .

A problem to be solved by the present invention is to provide a thinned polarizing plate.

Another problem to be solved by the present invention is to provide a polarizer excellent in durability at high temperature and high humidity.

Another object of the present invention is to provide a polarizing plate comprising an adhesive layer which is excellent in adhesion to a polarizer and which enhances 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 moisture permeability of 5 g / m 2 / 24h or less.

Another embodiment of the present invention is a polarizing plate comprising a polarizer, a protective film formed on one surface of the polarizer, and a pressure-sensitive adhesive layer comprising a (meth) acrylic copolymer formed on the other surface of the polarizer, The polarizer is characterized in that the rate of cracking of the polarizer is 0% after putting the substrate together and applying a pressure of 4 kg, then leaving it at 85 DEG C for 500 hours and standing at room temperature for 1 hour.

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

The polarizing plate of the present invention has excellent durability at high temperature and high humidity, has excellent adhesion to a polarizer, and can form a pressure-sensitive adhesive layer for enhancing crack resistance of the polarizer, so that a protective film can be omitted.

1 is a cross-sectional view of a polarizer according to one embodiment of the present invention.
2 is a cross-sectional view of a liquid crystal display device according to one 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.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings. However, the techniques disclosed in this application are not limited to the embodiments described herein but may be embodied in other forms. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of this invention to those skilled in the art. In the drawings, the width, thickness, and the like of the components are enlarged in order to clearly illustrate the components of each device. Like numbers refer to like elements throughout the several views.

The terms "upper" and "lower" in this specification are defined with reference to the drawings, wherein "upper" may be changed to "lower", "lower" What is referred to as "on" may include not only superposition, but also intervening other structures in the middle. On the other hand, what is referred to as "directly on" or "directly above "

As used herein, "(meth) acryl" means acryl and / or methacryl.

As used herein, the term " unsubstituted or substituted "means that at least one hydrogen atom of the functional group is replaced by a C1 to C10 alkyl group, a hydroxyl group, an amino group, an C6 to C10 aryl group, a halogen, a cyano group, An alkyl group, or an arylalkyl group of C7 to C10.

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

1, a polarizer 100 according to an embodiment of the present invention includes a polarizer 110, a protective film 120 formed on one surface of the polarizer 110, and an adhesive layer (not shown) formed on the other surface of the polarizer 110 130).

The adhesive layer 130 is (meth) comprises an acrylic copolymer and a water vapor transmission rate 5g / m 2 / 24h or less. Specifically, the moisture permeability of the adhesive layer 130 may be less than 4g / m 2 / 24h or less, 3g / m 2 / 24h. In the above range, the polarizer is excellent in durability under high temperature and high humidity conditions, and a separate protective film or barrier film is not required, so that a thinned polarizer can be provided.

In this specification, the moisture permeability of the adhesive layer in this specification is obtained by laminating an adhesive layer having a thickness of 20 mu m and a TAC film having a thickness of 40 mu m and then cutting a sample having a diameter of 60 mm in accordance with JIS Z0208 regulation into a moisture permeable cup charged with 15 g of calcium chloride, And humidity of 85% RH for 24 hours, and then the weight of the increased calcium chloride was measured and evaluated.

The thickness of the polarizing plate 100 may be 200 占 퐉 or less. Specifically, the thickness of the polarizing plate 100 may be 180 탆 or less, more specifically 130 탆 or less, for example, 30 탆 to 80 탆. Within the above range, it is advantageous to provide a thin film polarizer that is thinned and lightweight.

The polarizing plate 100 may have a transmittance of 90% or more, specifically 90% to 100% at a wavelength of 400 nm to 700 nm. In the above range, the polarizing plate has improved optical characteristics and may be advantageously used in an optical display device.

The polarizing plate 100 may have a degree of polarization of 90% or more, specifically 90% to 100%. In the above range, the polarizing plate has improved optical characteristics and may be advantageously used in an 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 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 in which at least one of iodine and dichroic dye is adsorbed to a polyvinyl alcohol-based resin film, or a polyene-based polarizer produced by dehydrating a polyvinyl alcohol-based resin film.

The polyvinyl alcohol resin film may have a saponification degree of 85 mol% to 100 mol%, specifically 98 mol% to 100 mol%. Within the above range, it is advantageous to produce a polarizer, and sufficient optical characteristics and durability can be secured. The degree of polymerization of the polyvinyl alcohol-based resin film may be 1000 to 10,000, specifically 1500 to 5,000. Within the above-mentioned range, it is advantageous to produce a polarizer, and the polarizing plate can secure sufficient optical characteristics and durability.

For example, the polyvinyl alcohol polarizer is produced by adsorbing at least one of iodine and dichroic dye to a polyvinyl alcohol resin film and uniaxially stretching in the machine direction (MD) at a final stretching ratio of 2 to 8, specifically 3 to 6 . The stretching may include dry stretching, wet stretching, or a combination thereof. The " final stretching ratio " means the ratio of the length of the final polyvinyl alcohol-based polarizer to the initial length of the polyvinyl alcohol-based resin film. The polyene polarizer may be prepared by adding an acid catalyst to a polyvinyl alcohol-based resin film, followed by dewatering and drying. The acid catalyst may include an organic acid including an aromatic sulfonic acid such as toluenesulfonic acid, an inorganic acid, or a mixture thereof.

The thickness of the polarizer 110 may be 50 占 퐉 or less, specifically 30 占 퐉 or less, more specifically 5 占 퐉 to 30 占 퐉, for example, 10 占 퐉 to 25 占 퐉. Within the above range, it is advantageous to provide a thin film polarizer that is thinned and lightweight.

A 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 30g / m 2 / 24hr or less, in particular 5g / m 2 / 24hr to about 20g / m 2 / 24hr. In the above range, the protective film can prevent the external moisture from penetrating into the polarizer, thereby enhancing the durability of the polarizer at high temperature and high humidity.

The protective film 120 may have a front retardation (Ro) of 5,000 nm or more, specifically 5,000 nm to 15,000 nm, more specifically 10,100 nm to 12,000 nm at a wavelength of 550 nm. In the above-described range, iridescence spots can be prevented from occurring when the polarizing plate is used.

The protective film 120 may have a degree of biaxial (NZ) of 1.8 or less, specifically 1.0 to 1.8 according to the following formula 1 at a wavelength of 550 nm. In the above range, there may be a rainbow stain removal effect by birefringence.

<Formula 1>

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

In the above formula (1), nx, ny and nz are refractive indices in the x-axis, y-axis and z-axis directions of the protective film at a wavelength of 550 nm, respectively.

The protective film 120 may have a thickness direction retardation (Rth) of the following formula 2 at a wavelength of 550 nm of 15,000 nm or less, specifically 10,000 nm to 12,000 nm. In this range, the effect of removing rainbow stains due to birefringence can be excellent.

<Formula 2>

Rth = ((nx + ny) / 2 - nz) xd

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

The protective film 120 may have a refractive index nx in the x-axis direction and a refractive index ny in the y-axis direction of 1.65 or more at a wavelength of 550 nm, and the other value may be less than 1.65. In this case, the rainbow stain-preventing effect can be more excellent than when both nx and ny are less than 1.65 or both nx and ny are 1.65 or more. In one embodiment, nx can be 1.65 or more, specifically 1.67 to 1.75, and ny can be 1.45 to 1.55. In other embodiments, ny can be 1.65 or more, specifically 1.67 to 1.72, more specifically 1.69 to 1.72, and nx can be 1.45 to 1.55. At this time, | nx-ny | can be 0.1 to 0.2, specifically 0.12 to 0.18. The viewing angle can be further improved in the above range, and the rainbow stain-preventing effect can be further improved.

In the present specification, "x axis" means the slow axis, "y axis" means the fast axis, and z axis means thickness, and the x axis, y axis, and z axis are orthogonal to each other.

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

As used herein, the term &quot; optically transparent film &quot; means that the transmittance is 90% or more. Specifically, the protective film 120 may have a transmittance of 90% to 100%, more specifically, 98% to 100%. In the above range, the polarizing plate has improved optical characteristics and may be advantageously used in an optical display device.

The protective film 120 may further include a functional coating layer on one side of the protective film to provide additional functions to the polarizing plate. Specifically, the functional coating layer may be at least one of a hard coating layer, an antireflection layer, an antistatic layer, an antistatic layer, and a low reflection layer, but is not limited thereto. The functional coating layer may have a thickness of 1 탆 to 100 탆, specifically 1 탆 to 50 탆, more specifically 1 탆 to 20 탆. It is possible to provide an additional function to the polarizing plate without affecting the protective film in the above range and it may be advantageous to be used for the polarizing plate.

The protective film 120 may further include a primer layer on one surface in a direction in which the polarizer is attached. In this case, the adhesive layer can make the polarizer and the protective film more adhered to each other. The primer layer may be a hydrophilic surface modifying 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 a polyester-based resin and a polyvinyl acetate-based resin. The primer layer may have a thickness of 1 nm to 100 nm, specifically 1 nm to 50 nm, more specifically 1 nm to 20 nm. It is possible to increase the adhesion of the protective film to the polarizer in the above range and to increase the total light transmittance.

The protective film 120 may have a thickness of 5 占 퐉 to 200 占 퐉, specifically 10 占 퐉 to 150 占 퐉, more specifically 50 占 퐉 to 100 占 퐉, for example, 20 占 퐉 to 80 占 퐉. Within this range, it is possible to suppress the warp of the polarizing plate together with the barrier layer, while being advantageous in providing a thin and lightweight thin film polarizer.

The protective film 120 is obtained by melt-extruding a protective film composition containing a polyester resin to prepare a resin film, stretching the melt-extruded resin film only in TD (transverse direction) by 2 to 10 times, And heat-treating and stretching the film at a lower degree of tension and then stretching the film by tension-relaxation.

The protective film composition comprising a polyester resin may further contain usual additives in addition to the polyester resin. Specifically, the additive may include an ultraviolet absorber, a leveling agent, an antistatic agent, and the like.

The ultraviolet absorber may include a conventional ultraviolet absorber that absorbs light having a wavelength of 200 nm to 400 nm. Specifically, the ultraviolet absorber may include at least one of phenolic, benzotriazole, salicylic, triazine, and oxamide. Particularly, since the phenol-based ultraviolet absorber has high compatibility with polyester resin, it can be mixed well with polyester resin, thereby suppressing elution in the polyester film and suppressing hole formation in the film or surface, .

The TD stretching ratio of the melt extruded resin film may be 3 to 8 times. In the stretching ratio range, the protective film can further improve the effect of reducing iridescence. At this time, the melt-extruded resin film can be stretched to 1 to 1.1 in MD. "MD stretching 1 to 1.1" means that there is no further stretching except mechanical stretching which is inevitably caused by moving the film to the MD by a roller or the like during TD stretching of the melt extruded resin film.

The stretching may include at least one of dry stretching, wet stretching. The stretching temperature is preferably in the range of (Tg - 20) DEG C to (Tg + 20) DEG C, more preferably 70 DEG C to 150 DEG C, more specifically 80 DEG C to 130 DEG C, 90 &lt; 0 &gt; C to 120 &lt; 0 &gt; C. In the stretching ratio and the temperature range, the extruded resin can be uniformly and uniformly stretched.

TD stretching by heat treatment and tension-relaxation may be to stretch the resin film only to TD, but crystallize and stabilize the film by heat treatment. The heat treatment may be performed at a temperature of Tg or more of the polyester resin, specifically at 100 to 300 캜 for 1 second to 2 hours. The TD stretching ratio due to tension-relaxation may be 0 to 3 times, specifically 0.1 to 2 times, more specifically 0.1 to 1 time. The retardation value of the protective film can be maintained in the temperature and the stretching ratio range, and the crystallization effect and stabilization effect of the film can be further improved.

The melt extruded resin film may further have at least one layer of a functional coating layer and a primer layer formed on at least one surface before TD stretching.

The adhesive layer 130 is formed on the other surface of the polarizer 110 to protect the polarizer 110 from the opposite side of the protective film 120 with respect to the polarizer 110 and to prevent external moisture from penetrating into the polarizer 110 The durability of the polarizing plate 100 at high temperature and high humidity can be increased. The adhesive layer 130 has high adhesion to the polarizer 110 and can be formed directly on the polarizer 110. [ In this case, the thickness of the polarizing plate 100 is more advantageous.

The thickness of the adhesive layer 130 may be 50 占 퐉 or less, specifically 3 占 퐉 to 30 占 퐉, more specifically 5 占 퐉 to 25 占 퐉. In the above range, it is advantageous to be used for a polarizing plate, and it is possible to suppress the warp of the polarizing plate due to an appropriate thickness ratio to the protective film.

The thickness ratio (thickness of the adhesive layer: protective film thickness) of the protective film 120 to the adhesive layer 130 may be 1: 0.1 to 1: 67. In this case, it is advantageous to form a thin polarizing plate in which the protective film is formed only on one side of the polarizer. Specifically, the thickness of the adhesive layer: protective film is 1: 0.3 to 1:50, more specifically 1: 1 to 1:30, such as 1: 1 to 1:10, 1: 1 to 1: : 1 to 1: 4. Within this range, the effect of suppressing warping in the case where a protective film is formed on one side of the polarizer and an adhesive layer is formed on the other side can be further improved.

The adhesive layer 130 may be a cured product of a pressure-sensitive adhesive composition containing a (meth) acrylic copolymer. Hereinafter, the adhesive composition will be described.

The adhesive composition according to one embodiment of the present invention may include a (meth) acrylic copolymer.

The (meth) acrylic copolymer is obtained by copolymerizing a (meth) acrylate monomer (a1) having an alkyl group having from 11 to 20 carbon atoms, a hydroxyl group-containing (meth) acrylate monomer (a2), and a glass transition temperature (Tg) 0 &lt; 0 &gt; C of monomer (a3).

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 a carbon number of 11 to 20 is preferably selected from the group consisting of undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, (Meth) acrylate, octyl (meth) acrylate, heptadecyl (meth) acrylate oleyl (meth) acrylate, stearyl Lt; / RTI &gt;

In one embodiment, the (meth) acrylate monomer (a1) having an alkyl group having from 11 to 20 carbon atoms is selected from the group consisting of dodecyl (meth) acrylate, tetradecyl (meth) acrylate, oleyl (meth) acrylate, (Meth) acrylate, and stearyl (meth) acrylate. In this case, the barrier property to air and water vapor is improved, and the moisture permeability can be lowered.

The (meth) acrylate monomer having an alkyl group having 11 to 20 carbon atoms is contained in an amount of 5% by weight or more, specifically 5% by weight to 45% by weight, more specifically 5% by weight to 35% by weight, For example, from 5% by weight to 30% by weight or from 10% by weight to 20% by weight. In the above range, the pressure-sensitive adhesive layer has sufficient adhesion durability and moisture permeation inhibiting 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 of 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) may be at least one selected from the group consisting of 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2- Cyclohexanedimethanol mono (meth) acrylate, 1-chloro-2-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, (Meth) acrylate, 1,6-hexanediol mono (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, neopentyl glycol mono Acrylate, trimethylolethane di (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, 4-hydroxycyclopentyl (meth) 0.0 &gt; 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 carbon number of 1 to 5, a superior adhesion increasing effect can be realized.

In another embodiment, the hydroxyl group-containing (meth) acrylate monomer (a2) is selected from the group consisting of 2-hydroxyethyl (meth) acrylate, 2- hydroxypropyl (meth) acrylate, 2- (Meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl (meth) acrylate. In this case, not only the productivity is improved in the production of the pressure-sensitive adhesive layer, but also the adhesive force of the pressure-sensitive adhesive can be further improved.

The hydroxyl group-containing (meth) acrylate monomer (a2) may be contained in an amount of 0.5% by weight to 5% by weight based on the total weight of the monomer mixture, and the adhesion and reliability may be more excellent in the above range.

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

In the present specification, the glass transition temperature can be measured with respect to a homopolymer of each monomer to be measured, for example, using DSC Q20 from TA Instrument. Specifically, the homopolymer of each monomer was heated up to 160 ° C at a rate of 20 ° C / minute, and gradually cooled to maintain the equilibrium state at 50 ° C and the temperature was raised to 160 ° C at a rate of 10 ° C / After obtaining the data of the endothermic transition curve, 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 -150 ° C to 0 ° C is an alkyl (meth) acrylate monomer (a31) having 1 to 10 carbon atoms, a monomer (a32) having an ethylene oxide, (A35) having an amino group, a monomer having an amide group (a35), a monomer having an alkoxy group (a36), a monomer having a phosphoric acid group (a37), a monomer having a sulfonic acid group (a38) And the glass transition temperature (Tg) of the monomer (a39) and the silane group-containing monomer (a40) is -150 ° C to 0 ° C.

The alkyl (meth) acrylate monomer (a31) having 1 to 10 carbon atoms may specifically include unsubstituted linear or branched alkyl (meth) acrylate esters having 1 to 10 carbon atoms. (Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, (Meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, ethylhexyl (meth) acrylate, octyl Acrylate, decyl (meth) acrylate, and the like.

Preferably, by using an alkyl (meth) acrylic monomer having 4 to 8 carbon atoms, an effect of increasing initial adhesion can be further obtained.

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

As the monomer (a32) having an ethylene oxide, one or more (meth) acrylate monomers containing an ethylene oxide group (-CH 2 CH 2 O-) may be used. (Meth) acrylate, polyethylene oxide monoethyl ether (meth) acrylate, polyethylene oxide monopropyl ether (meth) acrylate, polyethylene oxide monobutyl ether (meth) acrylate, polyethylene oxide mono (Meth) acrylate, polyethylene oxide monoisobutyl ether (meth) acrylate, polyethylene oxide diethyl ether (meth) acrylate, polyethylene oxide monoisopropyl ether (meth) acrylate, polyethylene oxide monoisobutyl ether (Meth) acrylate such as polyethylene oxide mono-alkyl ether (meth) acrylate, polyethylene oxide mono-t-butyl ether (meth) acrylate and the like.

The monomer (a33) having propylene oxide may be, for example, at least one monomer selected from the group consisting of polypropylene oxide monomethyl ether (meth) acrylate, polypropylene oxide monoethyl ether (meth) acrylate, polypropylene oxide monopropyl ether (Meth) acrylate, polypropylene oxide diethyl ether (meth) acrylate, polypropylene oxide monoethyl ether (meth) acrylate, propylene oxide monobutyl ether (Meth) acrylate such as isopropyl ether (meth) acrylate, polypropylene oxide monoisobutyl ether (meth) acrylate, and polypropylene oxide mono butyl ether (meth) acrylate. have.

The monomer (a34) having an amine group may be, for example, monomethylaminoethyl (meth) acrylate, monoethylaminoethyl (meth) acrylate, monomethylaminopropyl (meth) acrylate, monoethylaminopropyl Acrylate such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, N-tert-butylaminoethyl (meth) acrylate and methacryloxyethyltrimethylammonium chloride Amino group-containing (meth) acryl-based monomer.

The monomer (a35) having an amide group may be, for example, (meth) acrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylol (meth) acrylamide, N- methoxymethyl (Meth) acrylate monomer such as N, N-methylenebis (meth) acrylamide, 2-hydroxyethyl acrylamide, etc. The monomer (a36) having an alkoxy group may be, for example, 2- Methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxypropyl (meth) acrylate, Acrylate, 2-methoxypentyl (meth) acrylate, 2-ethoxypentyl (meth) acrylate, 2-butoxyhexyl (meth) (Meth) acrylate, 3-butoxyhexyl (meth) acrylate, .

In one embodiment, examples of the monomer (a36) having an alkoxy group include 2-ethoxyethyl acrylate, 2-methoxyethyl acrylate, and the like.

The monomer (a37) having a phosphoric acid group is, for example, selected from the group consisting of 2-methacryloyloxyethyldiphenyl phosphate (meth) acrylate, trimethacryloyloxyethyl phosphate (meth) acrylate, triacryloyloxyethyl phosphate (Meth) acrylate and the like.

The monomer (a38) having a sulfonic acid group may be, for example, sulfones such as sodium sulfopropyl (meth) acrylate, sodium 2-sulfoethyl (meth) acrylate, sodium 2-acrylamido- An acrylic monomer having an acid group can be obtained.

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

The monomer (a40) having a silane group includes, for example, 2-acetoacetoxyethyl (meth) acrylate, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (p-methoxyethyl) silane, vinyltriacetyl A vinyl monomer having a silane group such as silane, methacryloyloxypropyltrimethoxysilane, or the like.

The monomer having a glass transition temperature (Tg) of -150 ° C to 0 ° C may be used in an amount of 50% by weight to 94.5% by weight, specifically 50% by weight to 90% by weight, for example, 80% by weight. In this range, excellent adhesion and reliability can be further improved.

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

The (meth) acrylic copolymer is obtained by copolymerizing a (meth) acrylate monomer (a1) having an alkyl group having from 11 to 20 carbon atoms, a hydroxyl group-containing (meth) acrylate monomer (a2), and a glass transition temperature (Tg) (Meth) acrylic acid monomer (a4), which comprises a monomer (a3) at 0 deg. C, and further copolymerizing a monomer mixture containing (meth) acrylic acid monomer (a4). In this case, a superior adhesion increasing effect can be realized.

 The (meth) acrylic acid monomer (a4) may contain 0.5 to 10% by weight of the hydroxyl group-containing (meth) acrylate monomer (a2) based on the total weight of the monomer mixture. In this range, excellent adhesion and reliability can be further improved.

 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 in the production of the (meth) acrylic copolymer.

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

As the crosslinking agent, a polyfunctional crosslinking agent may be used. Such a polyfunctional crosslinking agent may specifically include at least one selected from the group consisting of a polyfunctional (meth) acrylate crosslinking agent, an isocyanate crosslinking agent and an epoxy crosslinking agent.

More specifically, examples of the polyfunctional (meth) acrylate crosslinking agent include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di 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, allyl cyclohexyl di (meth) acrylate, tricyclodecane dimethanol Dimethylol dicyclopentanedi (meth) acrylate, ethylene oxide modified hexahydrophthalic acid di (meth) acrylate, tricyclodecanedimethanol (meth) acrylate, neopentyl Recurring modified trimethyl propane di (meth) acrylate, adamantane di (meth) acrylate or 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] Cast acrylate; (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) acryloxyethylisocyanurate; Tetrafunctional acrylates such as diglycerin tetra (meth) acrylate or pentaerythritol tetra (meth) acrylate; Pentafunctional acrylates such as dipentaerythritol penta (meth) acrylate; And 6-functional acrylates such as dipentaerythritol hexa (meth) acrylate and caprolactone-modified dipentaerythritol hexa (meth) acrylate, but the present invention is not limited thereto. These may be used alone or in combination of two or more. For example, by using a polyfunctional (meth) acrylate of a polyhydric alcohol having 2 to 20 hydroxyl groups, the crosslinking agent can be realized in a more excellent range of endurance reliability.

More specifically, the isocyanate compound is a compound having at least two isocyanate groups (-NCO) in the molecule, and examples thereof include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, Silylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, and the like. An adduct in which an isocyanate compound is reacted with a polyol such as glycerol or trimethylolpropane, or an isocyanate compound in the form of a dimer, a trimer or the like may be a crosslinking agent used in a pressure-sensitive adhesive. Of the above examples, two or more isocyanate compounds may be mixed and used

More specifically, the epoxy cross-linking agent is a compound having at least two epoxy groups in the molecule, and examples thereof include bisphenol A type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl Ether, glycerine triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylol propane triglycidyl ether, N, N-diglycidyl aniline, N, N, N ' Glycidyl-m-xylenediamine, and 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane. Of the above examples, two or more kinds of epoxy compounds may be mixed and used.

The crosslinking agent may be a mixture of two or more of a polyfunctional (meth) acrylate crosslinking agent, an isocyanate crosslinking agent and an epoxy crosslinking agent. In this case, the adhesive force of the pressure-sensitive adhesive composition can be further improved.

The crosslinking agent may be included in an amount of 0.01 to 20 parts by weight, specifically 0.5 to 2.0 parts by weight, specifically 1.0 to 16.0 parts by weight, based on 100 parts by weight of the (meth) acrylic copolymer. Within this range, the adhesive strength and reliability of the 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 the epoxy-based crosslinking agent to the isocyanate-based resin may be 2 to 100, and may be 4 to 50. Within this range, the adhesive strength and reliability of the adhesive layer can be further improved.

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

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

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 contained in an amount of 0.01 to 0.1 parts by weight, specifically 0.05 to 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 pressure-sensitive adhesive composition may further include hygroscopic fine particles to minimize the moisture permeability.

The hygroscopic fine particles may include, but are not limited to, at least one 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 improve compatibility. The fine particles are not limited in shape and size. Specifically, the fine particles may include particles having a shape such as a spherical shape, a plate shape, or an amorphous shape. The fine particles may have an average particle diameter of 1 nm to 200 nm, specifically 10 nm to 50 nm. The hardness of the barrier layer can be increased without affecting the surface roughness and transparency of the barrier layer in the above range.

The hygroscopic fine particles may be present in an amount of 0.1 to 10% By weight, specifically from 1% by weight to 10% by weight, more specifically from 1% by weight to 5% by weight. In the above range, the moisture resistance can be further improved without affecting the surface roughness and transparency of the adhesive layer.

The adhesive composition may further comprise additives. The additive may be at least one selected from the group consisting of a curing accelerator, an ionic liquid, a lithium salt, an inorganic filler, a softener, a molecular weight modifier, an antioxidant, an antioxidant, a stabilizer, a tackifier resin, a modified resin (polyol resin, phenol resin, acrylic resin, A coloring pigment, an extender pigment, a treating agent, a UV blocking agent, a fluorescent whitening agent, a dispersing agent, a heat stabilizer, a light stabilizer, an antioxidant, an antioxidant, Ultraviolet absorbers, antistatic agents, flocculants, lubricants and solvents.

The pressure-sensitive adhesive composition may have a viscosity at 25 DEG C of 100 cP to 6,000 cP, specifically 1000 cP to 5500 cP, more specifically 2000 cP to 4500 cP, for example 3000 cP to 4500 cP. In this range, the formation of the adhesive layer can be made 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 cracking rate of the polarizer is 0% after standing at 85 DEG C for 500 hours and then at room temperature for 1 hour.

Specifically, the adhesive layer is (meth) acrylic copolymer and a water vapor transmission rate can be not more than 5g / m 2 / 24h. The details of the adhesive layer are the same as described above.

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

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

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

The liquid crystal panel 210 is formed between the first polarizing plate 220 and the second polarizing plate 230 and can transmit the 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 may include an in-plane switching mode, a twist nematic mode, a VA (vertical alignment) mode, a PVA (patterned vertical alignment) quot; vertical alignment &quot; mode.

The second polarizer 230 may include a polarizer and a conventional polarizer including a protective film formed on at least one side of the polarizer. The polarizer polarizes the 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, and may be a cellulose resin including a polyester resin including a polyethylene terephthalate resin and a polyethylene naphthalate resin, a cycloolefin polymer (COP) resin, a triacetyl cellulose resin and the like, a polyacetal resin Non-cyclic polyolefin resins including acrylic resins, polycarbonate resins, styrene resins, vinyl resins, polyphenylene ether resins, polyethylene, and polypropylene, acrylonitrile-butadiene-styrene copolymer resins, A film containing at least one of a polyacrylate resin, a polyaryl sulfone resin, a polyether sulfone resin, a polyphenylene sulfide resin, a fluorine resin, and a (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 shows a case where the first polarizer 220 is a polarizer according to embodiments of the present invention. However, a 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 a conventional polarizing plate described above may also be included in the scope of the present invention. Also, the first polarizer 220 and the second polarizer 230 may all be included in the scope of the present invention in the case of a polarizer according to embodiments 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 a polarizing plate according to embodiments of the present invention .

Referring to FIG. 3, the first polarizer 220 includes a first protective film 222, a first polarizer 221, and a first adhesive layer 223 sequentially laminated, and the first adhesive layer 223 And may be formed directly on the liquid crystal panel 210.

The second polarizer 231 and the second adhesive layer 233 are sequentially laminated on the second polarizer 230 and the second adhesive layer 223 is laminated on the liquid crystal panel 210 May be formed directly below.

As described above, since the first adhesive layer 223 and the second adhesive layer 223, which have low moisture permeability and excellent durability in high temperature and high humidity, are provided, a polarizing plate having a reduced thickness by omitting the barrier film and the protective film can be provided.

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to embodiments of the present invention. However, the following examples are provided to aid 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%, degree of polymerization: 2000, thickness: 80 탆) was dipped in a 0.3% iodine aqueous solution to be dyed. The MD was uniaxially stretched at a draw ratio of 5.0. The stretched polyvinyl alcohol film was immersed in an aqueous 3% boric acid solution and a 2% potassium iodide aqueous solution to perform color correction. And dried at 50 DEG C for 4 minutes to prepare a polarizer (thickness: 23 mu m).

(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 DEG C), 20 g of dodecyl acrylate, 2 g of 2-hydroxyethyl methacrylate and 2 g of acrylic acid were charged into a 1 L four- Lt; 0 &gt; C. Initiator Azobisisobutyronitrile (0.06 g) was dissolved in 20 g of ethyl acetate and added. After reacting at 65 占 폚 for 3 hours, 170 g of methyl ethyl ketone was added and the mixture was cooled to 40 占 폚 to prepare a first (meth) acrylic copolymer having a viscosity of 4,500 cP.

1.2 g of an isocyanate-based crosslinking agent (Colonate-L, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a first crosslinking agent, 1.2 g of an epoxy crosslinking agent (TETRAD-C, manufactured by Mitsubishi Gas Chemical Co., ) And 1.0 g of silane coupling agent 3-glyoxylpropylmethoxysilane (KBM-403, Shinrytsu) were mixed and stirred at 25 캜 for 30 minutes 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 charged into a 1 L four-necked flask. Initiator Azobisisobutyronitrile (0.06 g) was dissolved in 20 g of ethyl acetate and added. After reacting at 65 DEG C for 3 hours, 170 g of methyl ethyl ketone was added and the mixture was cooled to 40 DEG C to obtain a second liquid having a viscosity of 4,300 cP (Meth) acrylic copolymer.

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 second (meth) acrylic copolymer prepared above 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 first (meth) acrylic copolymer prepared above 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 second (meth) acrylic copolymer prepared above in the amounts shown in Table 1 below .

Preparation Example 5:

The first crosslinking agent, the second crosslinking agent and the silane coupling agent were added to the first (meth) acrylic copolymer prepared above in the contents shown in the following Table 1, and 10 g of the acrylic-modified nano-clay (Closite 20A, Southern Clay) was added as the hygroscopic fine particles A polarizing plate was prepared in the same manner as in Example 1, except that it 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 charged into a 1 L four-necked flask, and the temperature was maintained at 70 캜. Initiator Azobisisobutyronitrile (0.06 g) was dissolved in 20 g of ethyl acetate and added. After reacting at 65 占 폚 for 3 hours, 170 g of methyl ethyl ketone was added and the mixture was cooled to 40 占 폚 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 the first crosslinking agent, the second crosslinking agent and the silane coupling agent were added to the above-prepared third (meth) acrylic copolymer in the amounts shown in Table 1 below .

ingredient Production Example 1 Production Example 2 Production Example 3 Production Example 4 Production Example 5 Production Example 6 point
Cling
article
castle
water
of

article
castle The first (meth) acrylic copolymer 100 - 100 - 100 - The second (meth) acrylic copolymer - 100 - 100 - - The third (meth) acrylic copolymer - - - - - 100 The first crosslinking agent 1.2 1.2 15 15 1.2 1.2 The 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 particulate - - - - 10 -

Example

Example 1

On one side of the polarizer protective film to the epoxy adhesive (adeka社) (a polyethylene terephthalate film, moisture permeability: 80㎛, Toyobo Product 10g / m 2 / 24hr, at a wavelength of 550nm Ro:: 10,000nm, thickness) Respectively. After laminating, ultraviolet rays were irradiated at 400 mW / cm 2 and 1000 mJ / cm 2 with a metal halide lamp.

A pressure-sensitive adhesive layer for a polarizing plate was formed on the other surface of the polarizer by applying the pressure-sensitive adhesive composition of Production Example 1, followed by drying at 100 ° C for 3 minutes to form a thickness of 20 μm. 23 占 퐉), and a pressure-sensitive adhesive layer (thickness: 20 占 퐉) were successively formed. The physical properties were measured on the basis of the following physical property evaluation method, and the results are shown in Table 2 below.

Examples 2 to 5 and Comparative Examples 1 to 2

A polarizing plate was produced in the same manner as in Example 1, except that the composition of the pressure-sensitive adhesive composition was changed to that shown in Table 1 below.

Property evaluation method

(1) Water vapor permeability of the pressure-sensitive adhesive layer: The moisture permeability of the pressure-sensitive adhesive layer was measured according to JIS Z0208 specification for a sample comprising a pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive composition of Production Examples 1 to 6 and having a thickness of 20 占 퐉 and a TAC film having a thickness of 40 占 퐉 Respectively. Specifically, a sample cut into a diameter of 60 mm was placed in a moisture-permeable cup charged with 15 g of calcium chloride, allowed to stand in a thermo-hygrostat at a temperature of 85 캜 and a humidity of 85% RH for 24 hours, and then the weight of the increased calcium chloride was measured. 3, the moisture permeability of the adhesive layer was evaluated.

<Formula 3>

Moisture permeability of adhesive layer = (TAC moisture permeability) - (sample moisture permeability)

(2) High-temperature durability (85 ° C): The polarizing plates prepared in Examples 1 to 5 and Comparative Example 1 were cut into 100 mm x 175 mm, and a glass substrate was laminated on the back of the adhesive layer. Respectively. In order to investigate the heat resistance characteristics of the specimens, the specimens were allowed to stand at 85 ℃ for 500 hours. After standing at room temperature for 1 hour, it was observed through the eyes or a microscope. In the case where a crack occurred, the case where it did not occur was indicated as X (crack occurrence rate: 0%).

(3) High Temperature / High Humidity Durability (85 DEG C / 85RH%): The polarizer prepared in Examples 1 to 5 and Comparative Example 1 was cut into 100 mm x 175 mm, and the glass substrate was laminated on the back surface of the adhesive layer. The pressure was applied to the specimen. In order to investigate the wet heat characteristics of the specimens, the surface of the adhesive layer was observed after 500 hours of relative humidity at 85 ℃ / 85%. After standing at room temperature for 1 hour, it was observed through the eyes or a microscope. In the case where a crack occurred, the case where it did not occur was indicated as X (crack occurrence rate: 0%).

Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Adhesive composition Production Example 1 Production Example 2 Production Example 3 Production Example 4 Production Example 5 Production 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 Water vapor permeability
(g / m 2 / 24h) 4.7 4.3 3.8 3.4 2.3 7.5 durability The adhesive layer
Bubble / lifting X X X X X X 85 ℃ Crack X X X X X X 85 [deg.] C / 85%
Crack X X X X X O

As shown in Table 2, it was found that the polarizer according to the embodiments of the present invention did not cause bubbling and lifting of the pressure-sensitive adhesive layer, and did not cause cracking of the polarizer 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) acrylate copolymer resin having no alkyl (meth) acrylate monomer having an alkyl group of 11 to 20 carbon atoms had a high moisture permeability, The polarizer was found to have low durability due to cracking of the polarizer in a high temperature and high humidity environment.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (17)

A polarizer, a protective film formed on one surface of the polarizer, and an adhesive layer formed on the other surface of the polarizer,
The adhesive layer is (meth) acrylic copolymer, and a polarizing plate, characterized in that water vapor permeability of not more than 5g / m 2 / 24h.
The method according to claim 1,
Wherein the (meth) acrylic copolymer is a copolymer of a monomer mixture comprising a (meth) acrylate monomer having an alkyl group having from 11 to 20 carbon atoms.
The method according to claim 1,
The (meth) acrylic copolymer is obtained by copolymerizing a (meth) acrylate monomer (a1) having an alkyl group having from 11 to 20 carbon atoms, a hydroxyl group-containing (meth) acrylate monomer (a2), and a glass transition temperature (Tg) Wherein the copolymer is a copolymer of a monomer mixture containing monomer (a3) at 0 ° C.
The method of claim 3,
Wherein the monomer mixture comprises 5 to 45% by weight of a (meth) acrylate monomer (a1) having an alkyl group having 11 to 20 carbon atoms, 0.5 to 5% by weight of a hydroxyl group-containing (meth) acrylate monomer (a2) And 50% by weight to 90% by weight of a monomer (a3) having a transition temperature (Tg) of -150 ° C to 0 ° C.
The method of claim 3,
Wherein the monomer mixture further comprises (meth) acrylic acid monomer (a4).
The method according to claim 1,
Wherein 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.
The method according to claim 6,
Wherein the crosslinking agent is contained in an amount of 0.01 to 20 parts by weight based on 100 parts by weight of the (meth) acrylic copolymer.
The method according to claim 6,
Wherein the crosslinking agent comprises an isocyanate crosslinking agent and an epoxy crosslinking agent, and the weight ratio of the isocyanate crosslinking agent to the epoxy crosslinking agent is 2 to 100.
The method according to claim 1,
The pressure-sensitive adhesive layer may further comprise hygroscopic fine particles having an average particle diameter of 1 nm to 200 nm,
Wherein the hygroscopic fine particles comprise at least one of clay, silica, aluminum oxide, zirconium oxide, and titanium oxide.
10. The method of claim 9,
Wherein the hygroscopic fine particles are contained in an amount of 0.1 wt% to 10 wt% of the adhesive layer.
10. The method of claim 9,
The adhesive layer has a water vapor transmission rate polarizing plate, characterized in that not more than 3g / m 2 / 24h.
The method according to claim 1,
Wherein the protective film has a front retardation (Ro) of 5,000 nm to 15,000 nm at a wavelength of 550 nm.
The method according to claim 1,
Wherein the protective film (120) has a refractive index nx in the x-axis direction and a refractive index ny in the y-axis direction of 1.65 or more at a wavelength of 550 nm, and the other value is less than 1.65.
The method according to claim 1,
Wherein the polarizer has a thickness of 200 mu m or less.
A polarizer comprising a polarizer, a protective film formed on one surface of the polarizer, and a pressure-sensitive adhesive layer comprising a (meth) acrylic copolymer formed on the other surface of the polarizer,
Wherein a glass substrate is laminated on the back surface of the polarizing plate and a pressure of 4 kg is applied, and the glass plate is allowed to stand at 85 캜 for 500 hours and at room temperature for 1 hour, and the cracking rate of the polarizer is 0%.
16. The method of claim 15,
The adhesive layer has a water vapor transmission rate polarizing plate, characterized in that not more than 5g / m 2 / 24h.
An optical display device comprising the polarizing plate of any one of claims 1 to 16.
KR1020150057555A 2015-04-23 2015-04-23 Polarizing plate and optical display apparatus comprising the same KR101854498B1 (en)

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KR20180074359A (en) * 2016-12-23 2018-07-03 삼성에스디아이 주식회사 Polarizing plate and optical display apparatus comprising the same
KR20210037570A (en) * 2019-09-27 2021-04-06 주식회사 엘지화학 Acryl-based adhesive composition, polarizing plate and display device

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