KR102472996B1 - Pressure-sensitive adhesive composition and the use thereof - Google Patents

Abstract

This application relates to an adhesive composition and its use. The present application can provide a pressure-sensitive adhesive composition capable of effectively blocking ultraviolet light including a blue region even when the amount of the ultraviolet absorber is reduced, and thus improving durability reliability. The pressure-sensitive adhesive composition of the present application may be used in, for example, a polarizing plate and an organic light emitting device.

Description

Pressure-sensitive adhesive composition and its use {PRESSURE-SENSITIVE ADHESIVE COMPOSITION AND THE USE THEREOF}

This application relates to an adhesive composition and its use.

In the case of conventional polarizers for OLED, UV absorbers that absorb light in the wavelength range of 380 nm to 420 nm are added to correct the visibility of OLED products, or dye compounds that absorb light in the wavelength range of 430 nm to 440 nm are added to protect the OLED blue light source element. And it plays a role in correcting the overall visual feeling of OLED products. The technology of correcting the luminous feeling by adding a UV absorber or a pigment compound is a common technique, but a considerable amount of the absorbing agent is required to implement the function of protecting the OLED blue light source element and correcting the luminous feeling. However, as the amount of the absorber increases, crystallization of the absorber may occur even after reliability or under room temperature storage conditions, and when the crystallization is severe, there is a very high possibility of causing defects in optical properties or appearance of the product.

Patent Document 1: Republic of Korea Patent Registration No. 10-1042477

The present application provides a pressure-sensitive adhesive composition capable of effectively blocking ultraviolet rays including a blue region even when the amount of the ultraviolet absorber is reduced, and thus improving durability reliability, and uses of the pressure-sensitive adhesive composition.

This application relates to an adhesive composition. The pressure-sensitive adhesive composition may include an adhesive resin and a UV absorber. The adhesive resin may be an acrylic polymer. The acrylic polymer may include alkyl (meth)acrylate and acrylic acid as a chromophore monomer as polymerized units.

The pressure-sensitive adhesive composition may have an average transmittance of less than 15% in a wavelength range of 380 nm to 430 nm. In the present specification, the average transmittance or transmittance of the pressure-sensitive adhesive composition may mean the average transmittance or transmittance measured in a cured state of the pressure-sensitive adhesive composition. The lower the transmittance of the pressure-sensitive adhesive composition in the range of 380 nm to 430 nm, the better the ability to absorb and block ultraviolet rays including the blue region. can

Such a pressure-sensitive adhesive composition can effectively block ultraviolet rays including a blue region, and thus, durability reliability can be improved. Hereinafter, the pressure-sensitive adhesive composition of the present application will be described in detail.

As the alkyl (meth)acrylate, an alkyl (meth)acrylate having an alkyl group having 1 to 14 carbon atoms may be used. Alkyl (meth)acrylate in the present specification means a monomer having no polar group such as a hydroxyl group described later. These monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, Acrylate, sec-butyl (meth)acrylate, pentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-ethylbutyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, lauryl (meth)acrylate or tetradecyl (meth)acrylate and the like can be exemplified.

The hydroxyalkyl (meth)acrylate may provide a polar functional group such as a hydroxyl group to the side chain or terminal of the acrylic polymer. The hydroxyalkyl (meth)acrylate may react with a multifunctional crosslinking agent described later by application of heat to realize a crosslinked structure or improve wettability of the pressure-sensitive adhesive layer. As the hydroxyalkyl (meth)acrylate, a hydroxyalkyl (meth)acrylate having an alkyl group having 1 to 14 carbon atoms may be used. Such monomers include hydroxy ethyl (meth)acrylate, hydroxy propyl (meth)acrylate, hydroxy butyl (meth)acrylate, hydroxy hexyl (meth)acrylate, hydroxy octyl (meth)acrylate, hydroxy octyl (meth)acrylate, hydroxy nonyl (meth)acrylate, hydroxy lauryl (meth)acrylate or hydroxy tetradecyl (meth)acrylate and the like can be exemplified.

The alkyl (meth)acrylate may be included in the range of 70 to 99 parts by weight, specifically 80 to 99 parts by weight, based on 100 parts by weight of the total monomers constituting the acrylic polymer. In this specification, the term part by weight may refer to a weight ratio between components unless otherwise specified.

The chromophore monomer may include acrylic acid. In one example, the chromophore monomer may further include (meth)acrylate having an aromatic group. Examples of the aromatic group include a benzyl group, a benzyloxy group, a phenyl group, a phenoxy group, a phenylthio group, a naphthyl group, or a naphthyloxy group. In one example, the aromatic group may be a benzyl group. That is, the (meth)acrylate having an aromatic group may be benzyl (meth)acrylate.

According to one embodiment of the present application, the pressure-sensitive adhesive composition may include only acrylic acid as a chromophore monomer or both acrylic acid and (meth)acrylate having an aromatic group. The pressure-sensitive adhesive composition of the present application can effectively block ultraviolet rays even when the amount of the ultraviolet absorber is reduced by copolymerizing the chromophore monomer as described above with an acrylic polymer, and thus durability reliability can be improved.

The chromophore monomer may be included in the range of 1 to 50 parts by weight based on 100 parts by weight of the total monomers constituting the acrylic polymer. When the pressure-sensitive adhesive composition contains only acrylic acid as a chromophore monomer, the content of the chromophore monomer may mean the content of acrylic acid. When the pressure-sensitive adhesive composition includes both acrylic acid and (meth)acrylate having an aromatic group as chromophore monomers, the content of the chromophore monomer may mean the total weight of acrylic acid and (meth)acrylate having an aromatic group. Specifically, the chromophore monomer may be included in the range of 5 to 45 parts by weight, 10 to 40 parts by weight, 15 to 35 parts by weight, or 15 to 25 parts by weight based on 100 parts by weight of the total acrylic polymer. If the content of the chromophore monomer is too low, an ultraviolet absorber should be further included, and if the content is too high, physical properties of the pressure-sensitive adhesive, for example, glass adhesion and hardness may be affected, so the content may be preferably within the above range.

When the pressure-sensitive adhesive composition includes acrylic acid as a chromophore monomer, acrylic acid may be included within the range of 1 to 10 parts by weight, 2 to 8 parts by weight, 3 to 7 parts by weight, or 5 to 6 parts by weight based on 100 parts by weight of the total acrylic polymer. have. When the pressure-sensitive adhesive composition includes both acrylic acid and (meth)acrylate having an aromatic group as chromophore monomers, the (meth)acrylate having an aromatic group may be included in an amount of 300 to 500 parts by weight based on 100 parts by weight of acrylic acid.

The weight average molecular weight (Mw) of the acrylic polymer may be, for example, 1 million or more. In the present specification, the term weight average molecular weight is a value in terms of standard polystyrene measured by GPC (Gel Permeation Chromatograph), and in the present specification, unless otherwise specified, "molecular weight" may mean "weight average molecular weight" have. By setting the molecular weight of the polymer to 1,000,000 or more, the durability of the pressure-sensitive adhesive can be maintained within an appropriate range. The upper limit of the molecular weight is not particularly limited, and may be adjusted in the range of about 2.5 million or less, for example, in consideration of coating properties.

Acrylic polymers can be prepared through known polymerization methods. For example, a monomer mixture in which the monomers are appropriately blended according to a desired weight ratio is subjected to solution polymerization, photo polymerization, bulk polymerization, suspension polymerization, or emulsion polymerization ( Acrylic polymers can be prepared by applying a conventional polymerization method such as emulsion polymerization. A polymerization initiator or chain transfer agent may also be used together if necessary in the polymerization process.

The acrylic polymer may be a random copolymer. In the present specification, a random copolymer may refer to a polymer in which two or more monomers constituting the polymer are randomly connected. Accordingly, the acrylic polymer may have a structure different from that of the block copolymer.

In the present specification, the ultraviolet absorber exhibits the minimum transmittance in the wavelength range of ultraviolet rays, for example, 10 nm to 400 nm in the transmittance spectrum for wavelengths, or the ultraviolet rays, for example, 10 nm to 400 nm in the absorbance spectrum for wavelengths. It may refer to a compound exhibiting maximum absorbance in the wavelength region. In the present specification, the maximum absorption wavelength of the ultraviolet absorber may mean a wavelength exhibiting the minimum transmittance or the maximum absorbance. According to one embodiment of the present application, the maximum absorption wavelength of the ultraviolet absorber may be within a range of 380 nm to 420 nm. When the maximum absorption wavelength of the ultraviolet absorber is within the above range, the OLED Blue light source element can be effectively protected, and when applied to a polarizing plate, it is possible to provide a pressure-sensitive adhesive composition that exhibits excellent durability during reliability evaluation without deteriorating the optical properties of the polarizing plate. .

The UV absorber may include at least one selected from the group consisting of a malononitrile-based compound, a malonic acid-based compound, and a pyrazoline-based compound.

As the malononitrile-based compound, a compound including a structure derived from malononitrile and having a maximum absorption wavelength within the above range may be used. Malononitrile has the chemical structure of CH ₂ (CN) ₂ .

In one example, the malononitrile-based compound may be a compound represented by Formula 1 or Formula 2 below.

[Formula 1]

[Formula 2]

In Formula 1, L ₁ is a single bond, an alkylene group, an alkenylene group, an alkynylene group, -COO- or -OCO-, and R ₁ to R ₅ are each independently hydrogen, halogen, an alkyl group, an alkenyl group, or an alkynyl group. , an alkoxy group, an alkoxycarbonyl group, a hydroxy group, a cyano group or a nitro group. According to an embodiment of the present application, in Formula 1, L ₁ may be an alkenylene group, for example, an alkenylene group having 1 to 4 carbon atoms or 1 to 2 carbon atoms. The L ₁ may be, for example, an alkenylene group including one double bond. In addition, any one substituent of R ₁ to R ₅ may be an alkoxy group, for example, an alkoxy group having 1 to 4 carbon atoms, more specifically a methoxy group, and the other substituent may be a hydroxy group, and the other three A substituent may be hydrogen.

In Formula 2, L ₂ is a single bond, an alkylene group, an alkenylene group, an alkynylene group, -COO- or -OCO-, and R ₆ to R ₁₁ are each independently hydrogen, halogen, an alkyl group, an alkenyl group, an alkynyl group, or is an alkoxy group. According to an embodiment of the present application, in Formula 2, L ₂ may be an alkenylene group, for example, an alkenylene group having 1 to 4 carbon atoms or 1 to 2 carbon atoms. The L ₂ may be, for example, an alkenylene group containing one double bond. Also, any one substituent of R ₆ to R ₇ may be an alkyl group, for example, an alkyl group having 1 to 4 carbon atoms, more specifically a methyl group, and the other substituent may be hydrogen. In addition, any one substituent of R ₈ to R ₉ may be an alkoxy group, for example, an alkoxy group having 1 to 4 carbon atoms, more specifically an ethoxy group, and the other substituent may be hydrogen. Further, R ₁₀ to R ₁₁ may each be an alkyl group, for example, an alkyl group having 1 to 12 carbon atoms, an alkyl group having 1 to 8 carbon atoms, or an alkyl group having 2 to 6 carbon atoms, and more specifically, may be a butyl group, and R ₁₀ to R ₁₁ may be an alkyl group having the same number of carbon atoms.

As the malonic acid-based compound, a compound having a structure derived from malonic acid (or propanedioic acid) and having a maximum absorption wavelength within the above range may be used. Malonic acid is a dicarboxylic acid with the structure CH ₂ (COOH) ₂ .

In one example, the malonic acid compound may be a compound represented by Formula 3 below.

[Formula 3]

In Formula 3, L ₃ is a single bond, an alkylene group, an alkenylene group, an alkynylene group, -COO- or -OCO-, and R ₁₂ to R ₁₅ are each independently hydrogen, halogen hydrogen, halogen, an alkyl group, an alke It is a nyl group, an alkynyl group, an alkoxy group, an alkoxycarbonyl group, a cyano group, or a nitro group. According to an embodiment of the present application, in Formula 2, L ₃ may be an alkenylene group, for example, an alkenylene group having 1 to 4 carbon atoms or 1 to 2 carbon atoms. The L ₃ may be, for example, an alkenylene group including one double bond. In Formula 3, R ₁₂ , R ₁₃ , R ₁₄ , and R ₁₅ may each be an alkyl group, for example, an alkyl group having 1 to 4 carbon atoms or 1 to 2 carbon atoms, more specifically, a methyl group.

As the pyrazoline-based compound, a compound having a structure derived from pyrazoline and having a maximum absorption wavelength within the above range may be used. Pyrazoline is a heterocyclic compound with the molecular formula C ₃ H ₆ N ₂ .

In one example, the pyrazoline-based UV absorber may be a compound represented by Formula 4 below.

[Formula 4]

In Formula 4, L ₄ , L ₅ and L ₆ are each independently a single bond, an alkylene group, an alkenylene group, an alkynylene group, -COO- or -OCO-, and R ₁₆ , R ₁₇ and R ₁₈ are each independently hydrogen, halogen hydrogen, halogen, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an alkoxycarbonyl group, a cyano group or a nitro group. According to an embodiment of the present application, in Formula 4, L ₄ and L ₅ may each be a single bond, and L ₆ may be an alkenylene group, for example, an alkenylene group having 1 to 4 carbon atoms or 1 to 2 carbon atoms. have. The L ₆ may be, for example, an alkenylene group including one double bond. In Formula 4, R ₁₆ and R ₁₈ may each be an alkyl group, for example, an alkyl group having 1 to 8 carbon atoms or 1 to 4 carbon atoms, specifically, 4 carbon atoms, and R ₁₇ may be hydrogen.

In this specification, halogen may be exemplified by chlorine, bromine or iodine.

In this specification, the alkyl group or alkylene group is a straight or branched chain alkyl or alkylene group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, or an alkylene group, unless otherwise specified. It may mean a cycloalkyl group or an alkylene group having 3 to 20 carbon atoms, 3 to 16 carbon atoms, or 4 to 12 carbon atoms. The alkyl group or alkylene group may optionally be limited by one or more substituents.

In the present specification, the alkenyl group or alkenylene group has 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, and 1 to 4 carbon atoms unless otherwise specified. or a cycloalkenyl group or an alkenylene group having 3 to 20 carbon atoms, 3 to 16 carbon atoms, or 4 to 12 carbon atoms. The alkenyl group or alkenylene group may be optionally limited by one or more substituents.

In this specification, an alkynyl group or alkynylene group is a straight-chain or branched-chain alkynyl group or alkynylene group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, and 1 to 4 carbon atoms unless otherwise specified. or a cycloalkynyl group or alkynylene group having 3 to 20 carbon atoms, 3 to 16 carbon atoms, or 4 to 12 carbon atoms. The alkynyl group or alkynylene group may be optionally substituted by one or more substituents.

The UV absorber may be included in the range of 0.1 to 10 parts by weight based on 100 parts by weight of the acrylic polymer. If the content of the UV absorber is too high, it may affect adhesive properties or may cause crystallization during reliability evaluation. According to the present application, even with a small amount of the ultraviolet absorber within the above range, it is possible to effectively block ultraviolet rays in the blue region. Accordingly, durability reliability of the polarizing plate to which the pressure-sensitive adhesive composition is applied may be improved, and crystallization of the ultraviolet absorber may be reduced.

The pressure-sensitive adhesive composition may further include a crosslinking agent. The crosslinking agent may be a multifunctional crosslinking agent. The crosslinking agent may implement a crosslinked structure by reacting with the polymer through application of heat, for example.

As the crosslinking agent, a crosslinking agent such as an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, or a metal chelate crosslinking agent may be used, but is not limited thereto. The isocyanate crosslinking agent is a polyfunctional isocyanate compound such as tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isoborone diisocyanate, tetramethylxylene diisocyanate or naphthalene diisocyanate, or A compound obtained by reacting an isocyanate compound with a polyol compound such as trimethylol propane may be exemplified, and examples of the epoxy crosslinking agent include ethylene glycol diglycidyl ether, triglycidyl ether, trimethylol propane triglycidyl ether, N, N, At least one selected from the group consisting of N', N'-tetraglycidyl ethylenediamine and glycerin diglycidyl ether may be exemplified, and the aziridine crosslinking agent is N, N'-toluene-2,4-bis ( 1-aziridinecarboxamide), N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), triethylene melamine, bisisoprotaloyl-1-(2-methyl aziridine) and at least one selected from the group consisting of tri-1-aziridinylphosphine oxide, but is not limited thereto. In addition, as the metal chelate crosslinking agent, compounds in which a multivalent metal such as aluminum, iron, zinc, tin, titanium, antimony, magnesium, and/or vanadium are coordinated with acetyl acetone or ethyl acetoacetate may be exemplified. It is not limited. According to one embodiment of the present application, an isocyanate crosslinking agent may be used.

The crosslinking agent may be included in the pressure-sensitive adhesive composition in an amount of, for example, 0.01 to 10 parts by weight or 0.01 to 5 parts by weight based on 100 parts by weight of the acrylic polymer. Within this range, the cohesive strength or durability of the pressure-sensitive adhesive may be excellently maintained.

The pressure-sensitive adhesive composition may have an average transmittance of less than 15% in a wavelength range of 380 nm to 430 nm, and specifically may be 10% or less, 9% or less, 8% or less, or 7% or less. The pressure-sensitive adhesive composition may have a transmittance of 60% or less for a wavelength of 430 nm, and specifically, 55% or less or 50% or less. The pressure-sensitive adhesive composition may have a transmittance of 80% or more, specifically 85% or more or 90% or more for a wavelength of 450 nm. When the transmittance of the pressure-sensitive adhesive composition is within the above range, ultraviolet rays including a blue region can be effectively blocked.

In addition to the above components, the pressure-sensitive adhesive composition is a group consisting of an antioxidant, a UV stabilizer, a heat stabilizer, a plasticizer, an antistatic agent, a filler, an antifoaming agent, a surfactant, a nucleating agent, a flame retardant, a weathering stabilizer, a lubricant and a release agent for the purpose of preventing yellowing, etc. One or more additives selected from may be further added within a range capable of achieving the object of the present invention.

The pressure-sensitive adhesive composition may further include a solvent. Examples of the solvent include aromatic hydrocarbons such as toluene, benzene, and xylene; aliphatic hydrocarbons such as cyclohexane and decalin; esters such as ethyl acetate and butyl acetate; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; alcohols such as methanol, ethanol, isopropanol, butanol, isobutanol, methyl cellosolve, ethyl cellosolve, and butyl cellosolve; ethers such as tetrahydrofuran and dioxane; halogenated hydrocarbons such as dichloromethane, chloroform, and carbon tetrachloride; dimethylformamide; Dimethyl sulfoxide etc. are mentioned. These solvents may be used independently or may use 2 or more types together.

This application also relates to an adhesive layer. The pressure-sensitive adhesive layer may be a layer of the pressure-sensitive adhesive composition. In this specification, the term "layer of the pressure-sensitive adhesive composition" may mean a layer formed by coating or curing the pressure-sensitive adhesive composition. In this specification, the term "curing of the pressure-sensitive adhesive composition" may mean realizing a cross-linked structure in the pressure-sensitive adhesive composition through physical or chemical action or reaction of components included in the pressure-sensitive adhesive composition. In one example, in the pressure-sensitive adhesive layer, the acrylic polymer may exist in a crosslinked state by the crosslinking agent. Curing can be induced, for example, by holding at room temperature, applying moisture, applying heat, irradiating active energy rays, or proceeding two or more of the above processes together. Depending on each case, the type of pressure-sensitive adhesive composition in which curing is induced may be called, for example, a room temperature curable pressure sensitive adhesive composition, a moisture curable pressure sensitive adhesive composition, a heat curable pressure sensitive adhesive composition, an active energy ray curable pressure sensitive adhesive composition, or a hybrid curable pressure sensitive adhesive composition. .

This application also relates to polarizers. The polarizing plate may include a polarizer and an adhesive layer. The pressure-sensitive adhesive layer may include a cured product of the pressure-sensitive adhesive composition.

In this specification, the term polarizer refers to a film, sheet, or device having a polarization function. A polarizer is a functional element capable of extracting light vibrating in one direction from incident light vibrating in several directions.

The polarizer may be an absorption type polarizer. In this specification, an absorption type polarizer refers to an element that exhibits selective transmission and absorption characteristics with respect to incident light. The polarizer may be a linear polarizer. The absorption type polarizer may transmit light vibrating in one direction from incident light vibrating in various directions and absorb light vibrating in the other direction.

The polarizer may be a linear polarizer. In this specification, the linearly polarized light refers to a polarizer in which light selectively transmitted is linearly polarized light oscillating in one direction and light selectively absorbed is linearly polarized light oscillating in a direction orthogonal to the oscillation direction of the linearly polarized light.

As the polarizer, for example, a polarizer in which iodine is dyed on a polymer stretched film such as a PVA stretched film, or a liquid crystal polymerized in an aligned state as a host and an anisotropic dye arranged according to the alignment of the liquid crystal as a guest A guest-host type polarizer may be used, but is not limited thereto.

According to one embodiment of the present application, a stretched PVA film may be used as the polarizer. Transmittance or polarization degree of the polarizer may be appropriately adjusted in consideration of the purpose of the present application. For example, the transmittance of the polarizer may be 42.5% to 55%, and the degree of polarization may be 65% to 99.9997%.

The thickness of the pressure-sensitive adhesive layer may be appropriately adjusted in consideration of the purpose of the present application. The pressure-sensitive adhesive layer may have a thickness of about 1 μm to about 30 μm, for example. The thickness of the pressure-sensitive adhesive layer may be specifically 1 μm or more, 3 μm or more, or 5 μm or more, and may be 25 μm or less, 20 μm or less, or 15 μm or less. Within this thickness range, it may be advantageous to provide a pressure-sensitive adhesive composition having excellent durability when evaluating performance of blocking ultraviolet rays including a blue region, color characteristics and reliability of a polarizing plate.

The pressure-sensitive adhesive layer may have excellent blocking properties for ultraviolet rays including a blue region of 380 nm or more. Since the pressure-sensitive adhesive layer includes a cured product of the pressure-sensitive adhesive composition described above, it may exhibit substantially the same transmittance characteristics as those of the pressure-sensitive adhesive composition described above. Accordingly, the pressure-sensitive adhesive layer may have an average transmittance of less than 15% in a wavelength range of 380 nm to 410 nm, and specifically may be 10% or less, 9% or less, 8% or less, or 7% or less. The pressure-sensitive adhesive layer may have a transmittance of 60% or less for a wavelength of 430 nm, and specifically, 55% or less or 50% or less. The transmittance of the pressure-sensitive adhesive layer for a wavelength of 450 nm may be 80% or more, specifically 85% or more or 90% or more. In the present specification, the transmittance of a specific wavelength range is the transmittance of a specific wavelength within the range, or the transmittance of the specific wavelength within the above range. It may mean transmittance for a part of the wavelength range within the range, or transmittance for all wavelengths within the range.

The polarizing plate may have excellent blocking properties for ultraviolet rays including a blue region of 380 nm or more. Transmittance of the polarizing plate to light having a wavelength of 430 nm may be 25% or less, and specifically, 20% or less. Transmittance of the polarizing plate to light having a wavelength of 450 nm may be 30% or less, and specifically, 35% or more. The lower limits of transmittance for the light of 430 nm wavelength and 450 nm may be, for example, 10% or more, respectively. If the transmittance for light of 430 nm wavelength and 450 nm is too low, the b ^* value of the L ^* a ^* b ^* color coordinates may increase excessively and may not be suitable for neutral reflection visibility, so it may be advantageous to be within the above range.

The polarizing plate may have excellent durability. In one example, the polarizing plate may not be lifted at the interface of the pressure-sensitive adhesive layer in a high-temperature reliability evaluation at a temperature of 80 °C or a reliability evaluation when stored at a temperature of 60 °C and a relative humidity of 90% for 1000 hours. In addition, the polarizing plate may reduce a precipitation problem due to crystallization of the UV absorber in the reliability evaluation.

The pressure-sensitive adhesive layer may directly contact the polarizer, or another layer may be present between the pressure-sensitive adhesive layer and the polarizer.

In one example, the polarizing plate may further include a retardation layer. The retardation layer may have a function of converting circularly polarized light into linearly polarized light or linearly polarized light into circularly polarized light. The retardation layer may have a 1/4 wavelength phase retardation characteristic. The retardation layer may have an in-plane retardation value of 110 nm to 180 nm for light having a wavelength of 550 nm. In this specification, the in-plane retardation (Rin) is a value determined according to Equation 1 below. The slow axis of the retardation layer may form an angle of about 40 to 50 degrees, about 43 to 47 degrees, and preferably about 45 degrees to the absorption axis of the polarizer. The retardation layer may be a polymer stretched film or a cured layer of a liquid crystal compound.

[Equation 1]

Rin = d × (nx - ny)

In Equation 1, d is the thickness of the retardation layer, and nx, ny, and nz mean refractive indices of the retardation layer in the x-, y-, and z-axis directions, respectively. The x-axis means a direction parallel to the in-plane slow axis of the retardation layer, the y-axis means a direction parallel to the in-plane fast axis of the retardation layer, and the z-axis means the thickness direction of the retardation layer. The slow axis direction means a direction having the largest refractive index within a plane, the fast axis direction means a direction orthogonal to the slow axis within a plane of the retardation layer, and the thickness direction means a direction of a plane formed by the slow axis and the fast axis. Indicates the normal direction. In this specification, the refractive index refers to the refractive index for light having a wavelength of about 550 nm unless otherwise specified.

The retardation layer may have reverse wavelength dispersion. In the present specification, reverse wavelength dispersion may mean a characteristic that satisfies Equation 2 below.

[Equation 2]

Rin(450) < Rin(550)

In Equation 2, Rin(450) and R(550) are in-plane phase differences for light of 450 nm and 550 nm wavelengths, respectively.

When the polarizing plate includes the retardation layer, the pressure-sensitive adhesive layer may be present between the polarizer and the retardation layer or outside the retardation layer. In this specification, the outer side of the retardation layer may mean a position on the opposite side of the polarizer with respect to the retardation layer, and may include a position directly in contact with the retardation layer or a position not in direct contact with the retardation layer. In this specification, the outside of the polarizer may mean a position on the opposite side of the retardation layer with respect to the polarizer, and may include a position directly in contact with the polarizer or a position not in direct contact with the polarizer.

In one example, as shown in FIG. 1 , the pressure-sensitive adhesive layer may exist between the polarizer and the retardation layer. In the polarizing plate according to the structure of FIG. 1 , an intermediate layer to be described later, for example, the polarizer protective film, a retardation film other than the retardation layer, or a base film of the retardation film may or may not be included between the pressure-sensitive adhesive layer and the polarizer. may be According to this structure, it can be advantageous because it can protect the liquid crystal alignment layer included in the polarizing plate from additional ultraviolet rays. The liquid crystal alignment layer may be used when a liquid crystal film is used as the retardation layer.

The polarizing plate may further include an additional layer in addition to the retardation layer.

In one example, the polarizing plate may further include one or more of an upper layer existing outside the polarizer, a lower layer existing outside the retardation layer, and an intermediate layer existing between the polarizer and the retardation layer. The pressure-sensitive adhesive layer may be present at one or more of positions between the polarizer and the upper layer, between the polarizer and the intermediate layer, between the retardation layer and the intermediate layer, between the retardation layer and the lower layer, and on the outer side of the retardation layer.

As shown in FIG. 2 , the upper layer 103 may be stacked on the opposite side of the polarizer 101 facing the retardation layer 102 . In this case, the pressure-sensitive adhesive layer may be present at one or more of positions between the upper layer and the polarizer, between the polarizer and the retardation layer, and on the outside of the retardation layer.

Types of the upper layer may include, but are not limited to, a polarizer protective film, a hard coating layer, a retardation film other than the retardation layer, an antireflection layer, or a liquid crystal coating layer. The specific type of each component used as the upper layer is not particularly limited, and for example, various types of films used in the industry to configure optical films such as polarizing plates may be used without limitation. The upper layer may have a single layer of the above-exemplified layers or a multi-layer structure including a laminated structure of two or more layers among the above-exemplified layers.

As shown in FIG. 3 , the lower layer 203 may be stacked on the opposite side of the retardation layer 202 facing the polarizer 201 . In this case, the pressure-sensitive adhesive layer may be present at one or more of positions between the lower layer and the retardation layer, between the polarizer and the retardation layer, and on the outside of the retardation layer. Even in the case of FIG. 3, an upper layer as shown in FIG. 2 may be added. For example, in the state in which the lower layer exists as shown in FIG. 3, an upper layer such as a hard coating layer or a low reflection layer may be present on the outside of the polarizer, and a protective film may be present on one side or both sides of the polarizer.

As the type of the lower layer, a retardation film other than the retardation layer or a pressure-sensitive adhesive layer for attaching the polarizing plate to other elements, an adhesive layer, or a protective film or release film for protecting the pressure-sensitive adhesive layer or the adhesive layer may be exemplified. In this case, the pressure-sensitive adhesive layer as the lower layer may be the above-described pressure-sensitive adhesive layer of the present application.

As shown in FIG. 4 , the intermediate layer 303 may exist between the polarizer 301 and the retardation layer 302 . In this case, the pressure-sensitive adhesive layer may be present at one or more of positions between the intermediate layer and the polarizer, between the intermediate layer and the retardation layer, and on the outside of the retardation layer. Although not shown in the structure of FIG. 4, an upper layer of the structure of FIG. 2 and/or a lower layer of the structure of FIG. 3 may be present.

As the intermediate layer, the aforementioned polarizer protective film, a retardation film other than the retardation layer, or a base film of the retardation layer may be exemplified.

As the protective film of the polarizer or the base film of the retardation layer, for example, a cellulose film such as a TAC (Triacetyl cellulose) film; polyester films such as poly(ethylene terephthalate) (PET) films; polycarbonate film; polyethersulfone film; A polyolefin film such as an acrylic film and/or a polyethylene film, a polypropylene film, a polyolefin film containing a cyclo-based or norbornene structure, or an ethylene-propylene copolymer film may be used, but is not limited thereto.

As the retardation film other than the retardation layer, a retardation film having a positive thickness direction retardation may be exemplified. In the present specification, the thickness direction retardation (Rth) may be a value determined according to Equation 3 below. When the polarizing plate further includes a retardation film having a positive thickness direction retardation, antireflection properties and color properties may be excellent at a viewing angle. As the retardation film, a retardation film satisfying Equation 4 or 5 below may be used. A retardation film satisfying Equation 4 below may be referred to as a +C plate, and a retardation film satisfying Equation 5 may be referred to as a +B plate. Such a retardation film may include, but is not limited to, a polymer stretched film, a vertically aligned liquid crystal layer, a splay aligned liquid crystal layer, or a tilt aligned liquid crystal layer. In one example, projection of an optical axis (slow axis) of the retardation film onto a plane may be parallel or orthogonal to an absorption axis of the polarizer.

[Formula 3]

Rth = d Х (nz - ny)

[Formula 4]

nx = ny < nz

[Formula 5]

nx > ny and nz > ny

In Equation 3, d is the thickness of the retardation layer, and in Equations 3 to 5, nx, ny, and nz are each as defined above.

5 and 6 each exemplarily shows a structure of a polarizing plate according to an exemplary embodiment of the present application. The polarizing plate according to FIG. 5 includes a hard coating layer 403, a polarizer 401, a protective film 404 of the polarizer, a first adhesive layer 405, a base film 406 of a retardation layer, a retardation layer 402, +C A plate 407 and a second adhesive layer 408 may be sequentially included. The above-described pressure-sensitive adhesive layer of the present application may be used as the first pressure-sensitive adhesive layer and/or the second pressure-sensitive adhesive layer, for example, may be used as the first pressure-sensitive adhesive layer. The polarizing plate according to FIG. 6 includes a hard coating layer 403, a polarizer 401, a first adhesive layer 405, a base film 406 of a retardation layer, a retardation layer 402, a +C plate 407, and a second adhesive. Layer 408 may be sequentially included. The above-described pressure-sensitive adhesive layer of the present application may be used as the first pressure-sensitive adhesive layer and/or the second pressure-sensitive adhesive layer, for example, may be used as the first pressure-sensitive adhesive layer.

This application relates to an organic light emitting device. The organic light emitting device may include a polarizing plate and an organic light emitting panel. When the polarizing plate includes a retardation layer, the retardation layer may be disposed adjacent to the organic light emitting panel compared to the polarizer.

7 exemplarily shows the structure of the organic light emitting device of the present application. As shown in FIG. 7, the organic light emitting device includes a substrate 701, a first electrode layer 702, an organic light emitting layer 703, and a second electrode layer 704 sequentially provided on a first surface of the substrate, , the polarizing plate 100 provided on the second surface of the substrate.

A plastic substrate may be used as the substrate. An organic light emitting device including a plastic substrate may be advantageous in implementing a rollable, flexible, or bendable organic light emitting device.

The plastic substrate may include a polymer. Examples of the polymer include polyimide, polyamic acid, polyethylene naphthalate, polyether ether ketone, polycarbonate, polyethylene terephthalate, polyether sulfide, polysulfone, or acrylic polymer. In one example, in terms of process temperature, the plastic substrate may include polyimide having excellent high-temperature durability.

A light-transmitting substrate may be used as the substrate. The light-transmitting substrate may have transmittance of, for example, visible light of 50% or more, 60% or more, 70% or more, or 80% or more.

One of the first electrode layer and the second electrode layer may be an anode and the other may be a cathode. The anode is an electrode into which holes are injected and may be made of a conductive material having a high work function, and the cathode is an electrode into which electrons are injected and may be made of a conductive material having a low work function. In one example, the first electrode layer may be an anode, and the second electrode layer may be a cathode. In one example, the anode may be a transparent electrode, and the cathode may be a reflective electrode. The anode may include a transparent metal oxide such as ITO, IZO, AZO, GZO, ATO or SnO ₂ . The cathode may include a metal such as Ag, Au, Al, or the like.

The organic emission layer may include an organic material capable of emitting light when power is applied to the first electrode layer and the second electrode layer. In a structure called a so-called bottom emitting device, the first electrode layer may be formed of a transparent electrode layer, and the second electrode layer may be formed of a reflective electrode layer. In addition, in a structure called a so-called top emitting device, the first electrode layer is formed of a reflective electrode layer and the second electrode layer is formed of a transparent electrode layer. Light may be generated by recombination of electrons and holes injected by the electrode layer in the organic light emitting layer. Light may be emitted toward the substrate in the bottom emission type device and toward the second electrode layer in the top emission type device.

The organic light emitting layer may include a red light emitting layer, a green light emitting layer, and a blue light emitting layer. The light emitting layer may include a known organic material that emits red, green, and blue light, respectively. In one example, the organic light emitting device is driven in a method (RGB method) in which light emitting layers of three primary colors emit different colors and constitute one pixel (point, pixel), or light emitting layers of three primary colors are stacked to produce white. After constituting one pixel by emitting light, a color filter layer is placed in front of the white light emitting layer, so that it can be driven in a way (WOLED method) to implement various colors.

The organic light emitting panel may further include auxiliary layers between the first electrode layer and the organic light emitting layer and between the second electrode layer and the organic light emitting layer. The auxiliary layer may include a hole transporting layer for balancing electrons and holes, a hole injecting layer, an electron injecting layer, and an electron transporting layer. However, it is not limited thereto.

The organic light emitting display panel may further include an encapsulation substrate. The encapsulation substrate may be present on the second electrode layer. The encapsulation substrate may be made of glass, metal, and/or polymer, and may encapsulate the first electrode layer, the organic light emitting layer, and the second electrode layer to prevent moisture and/or oxygen from entering from the outside.

The polarizer may be disposed on a side where light is emitted from the organic light emitting device. For example, in the case of a bottom emission structure in which light is emitted toward the substrate, it may be disposed outside the substrate, and in the case of a top emission structure in which light is emitted toward the encapsulation substrate, it may be disposed outside the encapsulation substrate. The polarizing plate may improve visibility of the organic light emitting device by preventing external light from being reflected by a reflective layer made of metal such as electrodes and wires of the organic light emitting device and coming out to the outside of the organic light emitting device.

The present application can provide a pressure-sensitive adhesive composition capable of effectively blocking ultraviolet light including a blue region even when the amount of the ultraviolet absorber is reduced, and thus improving durability reliability. The pressure-sensitive adhesive composition of the present application may be used in, for example, a polarizing plate and an organic light emitting device.

1 to 6 exemplarily show the structure of a polarizing plate.
7 shows the structure of an organic light emitting device by way of example.

Hereinafter, the present application will be specifically described through examples according to the present application and comparative examples not according to the present application, but the scope of the present application is not limited by the examples presented below.

Example 1

Preparation of pressure-sensitive adhesive composition

94 parts by weight of n-butyl acrylate (n-BA) and 6 parts by weight of acrylic acid (AA) were introduced into a 1L reactor in which nitrogen gas was refluxed and a cooling device was installed to facilitate temperature control. Subsequently, 180 parts by weight of ethyl acetate (EAc) was introduced into the reactor as a solvent, and nitrogen gas was purged for 60 minutes to remove oxygen. Thereafter, the temperature was maintained at 67° C., and 0.05 parts by weight of azobisisobutyronitrile (AIBN) as a reaction initiator was added and reacted for 8 hours. After the reaction, it was diluted with ethyl acetate to prepare an acrylic polymer having a solid content concentration of 30% by weight and a weight average molecular weight of 1,000,000.

Based on 100 parts by weight of the acrylic polymer prepared above, 4 parts by weight of a malonic acid-based compound of Formula A (UV1990, Eutec Co., maximum absorption wavelength: 384 nm) as an ultraviolet absorber, and a crosslinking agent (XDI-based isocyanate, T-39M, Mitsuichemicals Co.) and a silane coupling agent (T-789J, Shinetsu Co., Ltd.) were mixed with a solvent so that the solid content concentration was 30% by weight to prepare an adhesive composition.

[Formula A]

Manufacture of adhesive

The prepared adhesive composition was coated on the release-treated surface of a release-treated poly(ethyleneterephthalate) (PET) film (MRF-38, Mitsubishi Co., thickness: 38 μm) to have a predetermined thickness after drying, and in an oven at 80 ° C. A pressure-sensitive adhesive layer was prepared by thermal curing for 3 minutes.

Manufacture of polarizer

A polyvinyl alcohol-based resin film was stretched, dyed with iodine, and treated with an aqueous solution of boric acid to prepare a polarizer. Subsequently, a 60 μm thick TAC (Triacetyl cellulose) film was attached to one side of the polarizer using a water-based polyvinyl alcohol-based adhesive. Subsequently, one surface of the prepared pressure-sensitive adhesive layer was laminated on the surface of the polyvinyl alcohol-based polarizer to which the TAC film was not attached using the same water-based polyvinyl alcohol-based adhesive as described above to prepare a polarizing plate.

Example 2

In Example 1, in the preparation of the acrylic polymer, n-butyl acrylate (n-BA) 96 parts by weight and acrylic acid (AA) 4 parts by weight except that the pressure-sensitive adhesive composition and pressure-sensitive adhesive were used in the same manner as in Example 1 and polarizing plates were prepared.

Example 3

In Example 1, except for using 81 parts by weight of n-butyl acrylate (n-BA), 15 parts by weight of benzyl acrylate (BzA) and 4 parts by weight of acrylic acid (AA) in the preparation of the acrylic polymer. An adhesive composition, an adhesive and a polarizing plate were prepared in the same manner as in Example 1.

Comparative Example 1

Except for using 99 parts by weight of n-butyl acrylate (n-BA) and 1 part by weight of 4-hydroxybutyl acrylate (4-HBA) in the preparation of the acrylic polymer in Example 1, Example 1 A pressure-sensitive adhesive composition, a pressure-sensitive adhesive and a polarizing plate were prepared in the same manner as above.

Comparative Example 2

In the preparation of the acrylic polymer in Example 1, 84 parts by weight of n-butyl acrylate (n-BA), 15 parts by weight of benzyl acrylate (BzA) and 1 part by weight of 4-hydroxybutyl acrylate (4-HBA) A pressure-sensitive adhesive composition, a pressure-sensitive adhesive and a polarizing plate were prepared in the same manner as in Example 1 except for using the part.

Evaluation Example 1. Permeability evaluation of pressure-sensitive adhesive composition

The transmittance in the cured state of the pressure-sensitive adhesive composition was measured by a UV spectrometer (Shimadzu Co.) after attaching a sample of the pressure-sensitive adhesive layer prepared in the preparation of the pressure-sensitive adhesive to a size of 4 cm × 4 cm (width × height) on glass. . Transmittance to light with a wavelength of 430 nm and 450 nm and average transmittance with respect to light with a wavelength of 380 nm to 430 nm were measured, and the results are shown in Table 1 below. As a result of the evaluation, the adhesive applied with acrylic acid of Examples 1 to 3 exhibited lower transmittance to light with a wavelength of 430 nm and a higher transmittance with respect to light with a wavelength of 450 nm compared to the adhesive to which acrylic acid was not applied with Comparative Examples 1 to 2. It exhibited high transmittance and exhibited a lower average transmittance for light with a wavelength of 380 nm to 430 nm.

Evaluation Example 2 Evaluation of optical properties of polarizing plate

Specimens were prepared by cutting the polarizing plates prepared in Examples and Comparative Examples to a size of 25 mm × 25 mm (width × length). By measuring the transmittance of the polarizing plate using a UV-visible spectrometer (V-7100, JASCO Co.), the UV blocking performance including the blue region was evaluated, and the results are shown in Table 2. The light transmittance in Table 2 below shows the light transmittance in % when the total light transmittance is set to 100.

As shown in Table 2 below, the polarizing plates including the pressure-sensitive adhesive to which acrylic acid of Examples 1 to 3 is applied are more sensitive to light with a wavelength of 430 nm compared to the polarizing plates including the pressure-sensitive adhesive to which acrylic acid is not applied in Comparative Examples 1 to 2. By exhibiting low transmittance, it can be seen that it has an effective blocking function for ultraviolet rays including the blue region.

Evaluation Example 3 Evaluation of reflective visibility of polarizer

Specimens were prepared by cutting the polarizing plates prepared in Examples and Comparative Examples to a size of 25 mm × 25 mm (width × length). The reflection luminous properties of the polarizer were evaluated by measuring L ^* a ^* b ^* color values for the reflection of the polarizer itself using a UV-visible spectrometer (V-7100, JASCO), and the results are shown in Table 2 . As a result of the evaluation, it can be confirmed that the reflective luminous feeling (a ^* , b ^* ) moves in a neutral direction, indicating an excellent reflective luminous feeling.

Evaluation Example 4 Durability evaluation under reliability conditions

Two specimens prepared by cutting the polarizers prepared in Examples and Comparative Examples to a size of 90 mm × 170 mm (width × length) were prepared for each Example and Comparative Example, respectively. Then, the prepared two specimens were attached to both sides of a glass substrate (110 mm × 190 mm × 0.7 mm = width × length × thickness) so that the optical absorption axes of each polarizer crossed each other, thereby preparing samples. The pressure applied during the attachment was about 5 Kg/cm ² , and the operation was performed in a clean room so that bubbles or foreign substances were not generated on the interface. After putting the prepared sample into a reliability chamber and leaving it for 1,000 hours under conditions of a temperature of 60° C. and a relative humidity of 90%, precipitation of the UV absorber at the interface of the pressure-sensitive adhesive layer and occurrence of lifting were observed. The durability evaluation criteria are as follows.

<Durability Evaluation Criteria>

◎: No precipitation and excitation

○: Precipitation and lifting occur finely

△: Precipitation and excitation occur

×: A large amount of precipitation and excitation occur

430 nm transmittance (%) 450 nm transmittance (%) 380 nm to 430 nm
Average transmittance (%) Example 1 46.08 92.43 6.87 Example 2 48.72 92.84 6.99 Example 3 43.81 91.4 6.34 Comparative Example 1 84.21 98.76 27.9 Comparative Example 2 79.82 98.05 25

Polarizer Transmittance (%) Polarizer Color Characteristics durability 430 nm 450 nm L ^* a ^* b ^* Example 1 16.83553 39.10736 67.60341 -5.56065 10.64641 ◎ Example 2 19.50102 39.8089 67.45401 -5.07846 9.70523 ◎ Example 3 16.92746 39.15267 67.42173 -5.45744 10.46326 ◎ Comparative Example 1 31.36419 39.62849 65.77632 -2.845 5.98569 ◎ Comparative Example 2 28.46365 39.17215 65.64736 -3.26434 6.84336 ◎

10: polarizer, 20: retardation layer, 30: adhesive layer
101, 201, 301, 401: polarizer; 20, 102, 202, 302, 402: retardation layer;
103: upper layer, 203: lower layer, 303: middle layer
403: hard coating layer, 404: protective film of polarizer, 405: first adhesive layer, 406: base film of retardation layer, 407: +C plate, 408: second adhesive layer, 100: polarizing plate,
701: substrate, 702: first electrode layer, 703: organic light emitting layer, 704: second electrode layer

Claims (15)

A pressure-sensitive adhesive composition comprising an acrylic polymer and an ultraviolet absorber,
The acrylic polymer includes alkyl (meth)acrylate and acrylic acid as a chromophore monomer as polymerized units,
In a cured state, the pressure-sensitive adhesive composition has an average transmittance of less than 15% in a wavelength range of 380 nm to 430 nm, and a transmittance of 60% or less for a wavelength of 430 nm,
Except for the case where the ultraviolet absorber has a polymerizable functional group,
The pressure-sensitive adhesive composition does not contain hydroxyalkyl (meth) acrylate. The pressure-sensitive adhesive composition according to claim 1, wherein the chromophore monomer further comprises (meth)acrylate having an aromatic group. The pressure-sensitive adhesive composition of claim 1, wherein the chromophore monomer is included within a range of 1 to 50 parts by weight based on 100 parts by weight of the acrylic polymer. The pressure-sensitive adhesive composition according to claim 1, wherein the maximum absorption wavelength of the ultraviolet absorber is within a range of 380 nm to 420 nm. The pressure-sensitive adhesive composition according to claim 1, wherein the ultraviolet absorber includes at least one selected from the group consisting of malononitrile-based compounds, malonic acid-based compounds, and pyrazoline-based compounds. The pressure-sensitive adhesive composition according to claim 5, wherein the malononitrile-based compound is a compound represented by Formula 1 or Formula 2 below:
[Formula 1]

[Formula 2]

In Formula 1, L ₁ is a single bond, an alkylene group, an alkenylene group, an alkynylene group, -COO- or -OCO-, and R ₁ to R ₅ are each independently hydrogen, halogen, an alkyl group, an alkenyl group, or an alkynyl group. , An alkoxy group, an alkoxycarbonyl group, a hydroxyl group, a cyano group, or a nitro group, and in Formula 2, L ₂ is a single bond, an alkylene group, an alkenylene group, an alkynylene group, -COO- or -OCO-, and R ₆ to R ₁₁ is each independently hydrogen, halogen, an alkyl group, an alkenyl group, an alkynyl group or an alkoxy group. The pressure-sensitive adhesive composition according to claim 5, wherein the malonic acid compound is a compound represented by the following formula (3):
[Formula 3]

In Formula 3, L ₃ is a single bond, an alkylene group, an alkenylene group, an alkynylene group, -COO- or -OCO-, and R ₁₂ , R ₁₃ , R ₁₄ and R ₁₅ are each independently hydrogen, halogen, An alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an alkoxycarbonyl group, a cyano group or a nitro group. The pressure-sensitive adhesive composition according to claim 5, wherein the pyrazoline-based compound is a compound represented by Formula 4:
[Formula 4]

In Formula 4, L ₄ , L ₅ and L ₆ are each independently a single bond, an alkylene group, an alkenylene group, an alkynylene group, -COO- or -OCO-, and R ₁₆ , R ₁₇ and R ₁₈ are each It is independently hydrogen, halogen, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an alkoxycarbonyl group, a cyano group or a nitro group. The pressure-sensitive adhesive composition of claim 1, wherein the UV absorber is included within a range of 0.1 to 10 parts by weight based on 100 parts by weight of the acrylic polymer. The pressure-sensitive adhesive composition according to claim 1, further comprising a multifunctional crosslinking agent. delete A polarizing plate comprising a polarizer and a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer includes a cured product of the pressure-sensitive adhesive composition of claim 1. 13. The polarizing plate of claim 12, wherein the polarizing plate has a transmittance of 25% or less for light having a wavelength of 430 nm and a transmittance of 30% or more for light having a wavelength of 450 nm. An organic light emitting device comprising an organic light emitting panel and the polarizing plate of claim 12. 15. The organic light emitting device of claim 14, wherein the organic light emitting panel sequentially includes a first electrode layer, an organic light emitting layer, and a second electrode layer on a plastic substrate, and the polarizing plate is disposed on one surface of the plastic substrate.

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