Polarizing plates and display devices

Abstract

The present invention provides a polarizing plate that has no protective layer on at least one surface of the polarizer and is equipped with a barrier layer that prevents the elution of dichroic substances from the polarizer after being left in high temperature and high humidity conditions for a long period of time. [Solution] A polarizing plate and display device are provided, comprising a polarizer and a barrier layer laminated on one surface of the polarizer. The barrier layer comprises a curable compound including an epoxy compound and a (meth)acrylic compound, a photoinitiator, and a metal chelating crosslinking agent, wherein the (meth)acrylic compound includes a cured product of a barrier layer composition containing a carboxyl group-containing (meth)acrylic compound.

Description

[Technical Field]

[0001] Embodiments of the present invention relate to polarizing plates and optical display devices. [Background technology]

[0002] Light-emitting devices, including organic light-emitting devices, do not necessarily need to have a polarizer. However, incident external light may degrade screen quality due to total internal reflection by the panel within the light-emitting device. For this reason, light-emitting devices generally have a polarizer on the upper surface of the panel. A polarizer consists of a polarizer and a phase difference film. The phase difference film may be a polymer film, but due to the recent trend towards thinner polarizers, liquid crystal films are used.

[0003] On the other hand, in recent years, with the trend towards thinner polarizing plates, a method has been proposed in which a barrier layer is laminated onto the polarizing plate instead of a protective layer. Since the barrier layer is generally formed by coating and curing a barrier layer composition, it can be provided thinner than existing protective layers.

[0004] The background art of this invention is disclosed in Korean Published Patent No. 10-2006-0103451, etc. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Korean Published Patent No. 10-2006-0103451 [Overview of the project] [Problems that the invention aims to solve]

[0006] One embodiment of the present invention provides a polarizing plate in which at least one surface of the polarizer lacks a protective layer and is equipped with a barrier layer that prevents the elution of dichroic substances from the polarizer after being left in high temperature and high humidity conditions for a long period of time.

[0007] One embodiment of the present invention provides a polarizing plate that has no protective layer on at least one surface of the polarizer and is equipped with a barrier layer to prevent discoloration of the polarizer after being left in high temperature and high humidity for a long period of time.

[0008] One embodiment of the present invention provides a polarizing plate comprising a barrier layer formed of a barrier layer composition that has a long usable time and excellent storage stability. [Means for solving the problem]

[0009] One perspective is that of a polarizing plate.

[0010] The polarizing plate includes a polarizer and a barrier layer laminated on one surface of the polarizer. The barrier layer includes a curable compound containing an epoxy compound and a (meth)acrylic compound, a photoinitiator, and a metal chelating crosslinking agent. The (meth)acrylic compound includes a cured product of a barrier layer composition containing a carboxyl group-containing (meth)acrylic compound.

[0011] Another perspective is that of optical display devices.

[0012] The optical display device includes the polarizing plate or barrier layer of the present invention. [Effects of the Invention]

[0013] Since there is no protective layer on at least one surface of the polarizer, a thinner polarizing plate can be provided.

[0014] By preventing the leaching of dichroic substances from polarizers after prolonged exposure to high temperature and humidity, corrosion of panels and other components can be prevented.

[0015] Because the polarizer does not decolorize after being left in high temperature and high humidity conditions for a long period of time, its reliability and durability can be improved.

[0016] By including a barrier layer formed from a barrier layer composition that has a long usable time and excellent storage stability, the productivity of polarizing plates can be improved.

Brief Description of the Drawings

[0017] [Figure 1] It is a cross-sectional view of a polarizing plate according to one embodiment. [Figure 2] It is a cross-sectional view of a polarizing plate according to another embodiment. [Figure 3] It is a schematic diagram for measuring the resistance of the polarizing plate. [Figure 4] It is a schematic diagram showing a schematic explanation for evaluating the decolorization (iodine removal) of the polarizer.

Embodiments for Carrying Out the Invention

[0018] Referring to the accompanying drawings, a person having ordinary knowledge in the technical field to which the present invention pertains will be described in detail so that the present invention can be easily implemented according to the embodiments. The present invention can be implemented in various different forms and is not limited to the embodiments described here.

[0019] In the drawings, parts not related to the description are omitted for clarity in explaining the present invention, and the same names are used for the same or similar components throughout the specification. In the drawings, the lengths and sizes of each component are for explaining the present invention, and the present invention is not limited to the lengths and sizes of each component described in the drawings.

[0020] In this specification, "upper" and "lower" are defined based on the drawings, and depending on the viewing perspective, "upper" may become "lower" and "lower" may become "upper". What is referred to as "on" may include not only directly above but also cases where another structure intervenes in the middle. On the other hand, what is referred to as "directly on" or "right above" or "formed directly" means that no other structure such as an intermediate intervenes.

[0021] The terms used herein are for illustrative purposes only and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0022] In this specification, the "in-plane retardation (Re)" of an optical element is represented by the following formula A. [Formula A] Re = (nx - ny) × d

[0023] In Formula A, nx and ny are the refractive indices in the slow axis direction and the fast axis direction of the optical element at the measurement wavelength, respectively, and d is the thickness of the optical element (unit: nm).

[0024] In this specification, "reverse wavelength dispersion" means Re(450) < Re(550) < Re(650).

[0025] When describing a numerical range in this specification, "X~Y" means "X or more and Y or less".

[0026] The present invention relates to a polarizing plate having no protective layer on at least one surface of a polarizer. The polarizing plate includes a barrier layer instead of a protective layer.

[0027] Here, the "protective layer" means an optical element that is laminated on one surface of a polarizer and functions to protect the polarizer. The protective layer may be a film or a coating layer. The protective layer may be a liquid crystal layer or a non-liquid crystal layer. The protective layer can also have an in-plane retardation within a predetermined range at a wavelength of 550 nm, or may have no in-plane retardation.

[0028] In one embodiment, the protective layer is an optically transparent protective film or protective coating layer, and may include ordinary ones known to those skilled in the art. For example, the protective film may include one or more cellulose ester resins containing triacetylcellulose (TAC), cyclic polyolefin (COP) resins containing amorphous cyclic polyolefins, polycarbonate resins, polyester resins containing polyethylene terephthalate (PET), polyethersulfone resins, polysulfone resins, polyamide resins, polyimide resins, acyclic polyolefin resins, polyacrylate resins containing polymethyl methacrylate resins, polyvinyl alcohol resins, polyvinyl chloride resins, and polyvinylidene chloride resins.

[0029] In one embodiment, the barrier layer may be formed directly on the polarizer. Here, "formed directly" means that there is no adhesive or tacky layer between the polarizer and the barrier layer, and the barrier layer is formed on the polarizer. For example, the barrier layer can be formed by directly coating or applying the barrier layer composition described below to one surface of the polarizer, followed by drying and curing.

[0030] In one embodiment, the polarizing plate may include a polarizer, a protective layer laminated on one side of the polarizer, and a barrier layer laminated on the other side of the polarizer.

[0031] As explained below, the barrier layer can be formed by applying a barrier layer composition to one surface of the polarizer and then curing it. Therefore, the barrier layer is formed to be thin. Polarizers contain dichroic substances such as iodine to exhibit polarizing performance. If polarizers are left in high temperature and high humidity conditions for a long period of time, dichroic substances such as iodine may leach out. The leached dichroic substances may corrode the optical display panel, especially the substrate, to which the polarizer is attached.

[0032] One embodiment of the polarizing plate includes a barrier layer, as described below, which prevents dichroic substances leached from the polarizer from passing through the barrier layer after being left in high temperature and high humidity conditions for a long period of time, thereby preventing corrosion of the panel, including the substrate.

[0033] One embodiment of the polarizing plate, by including the barrier layer described below, can improve reliability and durability because it prevents decolorization of the polarizer.

[0034] In one embodiment, the polarizing plate exhibits excellent productivity by including a barrier layer formed from a barrier layer composition that has a long usable time and excellent storage stability.

[0035] The following describes one embodiment of a polarizing plate.

[0036] A polarizing plate includes a polarizer and a barrier layer laminated on one surface of the polarizer.

[0037] Barrier layer The barrier layer comprises a curable compound including an epoxy compound and a (meth)acrylic compound, a photoinitiator, and a metal chelating crosslinking agent, wherein the (meth)acrylic compound includes a cured product of a barrier layer composition containing a carboxyl group-containing (meth)acrylic compound.

[0038] In one embodiment, the barrier layer may be a double cured or composite cured product of the barrier layer composition, which is photocured and thermally cured.

[0039] In one embodiment, the barrier layer may include an epoxy compound, a (meth)acrylic compound, a photoinitiator, and a metal chelating crosslinking agent. These may be derived from a barrier layer composition.

[0040] In one embodiment, the curable compound may be contained in the barrier layer composition at an amount of 90% by weight or more, for example, 90% to 95% by weight, based on the solid content.

[0041] In one embodiment, the total amount of the epoxy compound and the (meth)acrylic compound may be 95 parts by weight or more per 100 parts by weight of the curable compound, for example, 99 parts by weight to 100 parts by weight or 100 parts by weight. By satisfying this range, the adhesion, reliability, and compatibility of the barrier layer to the polarizer can be increased.

[0042] The curable compound may also be a photocurable compound.

[0043] (A) Epoxy compounds

[0044] (A) The epoxy compound may be contained in an amount of 50 to 70 parts by weight per 100 parts by weight of the curable compound. By satisfying this range, it is possible to prevent insufficient adhesion to the polarizer due to a lack of (meth)acrylic compound, and to prevent discoloration of the polarizer after being left in high temperature and high humidity for a long period of time due to insufficient bonding strength with the polarizer caused by a decrease in the overall glass transition temperature of the barrier layer. Preferably, (A) the epoxy compound may be contained in an amount of 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70 parts by weight, or 60 to 70 parts by weight.

[0045] (A) The epoxy compound may include one or more alicyclic epoxy compounds, aliphatic epoxy compounds, aromatic epoxy compounds, and hydrogenated aromatic epoxy compounds.

[0046] In one embodiment, (A) the epoxy compound may include one or more alicyclic epoxy compounds and aliphatic epoxy compounds. When alicyclic epoxy compounds and aliphatic epoxy compounds are included in the barrier layer composition together with the (meth)acrylic compounds described below, the effect of the barrier layer can be easily achieved.

[0047] For example, (A) the epoxy compound may include a mixture of an alicyclic epoxy compound and an aliphatic epoxy compound. In one embodiment, the mixture of the alicyclic epoxy compound and the aliphatic epoxy compound may be included in an amount of 95 parts by weight or more, for example, 95 parts by weight to 100 parts by weight or 100 parts by weight, per 100 parts by weight of the epoxy compound. By satisfying this range, the effect of the barrier layer can be easily achieved.

[0048] As the alicyclic epoxy compound, a bifunctional alicyclic epoxy compound can be used. The bifunctional alicyclic epoxy compound may include a compound having a carbon chain between two alicyclic epoxy groups. For example, the alicyclic epoxy compound may include one or more of the following: 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 1,2-epoxy-4-vinylcyclohexane, 1,2-epoxy-1-methyl-4-(1-methylepoxyethyl)cyclohexane, 4-(1,2-epoxyethyl)-1,2-epoxycyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol, ethylenebis(3,4-epoxycyclohexanecarboxylate), oxydiethylenebis(3,4-epoxycyclohexanecarboxylate), 1,4-cyclohexanedimethylbis(3,4-epoxycyclohexanecarboxylate), and 3-(3,4-epoxycyclohexylmethoxycarbonyl)propyl 3,4-epoxycyclohexanecarboxylate. (A) The epoxy compound may contain one or more of the above-mentioned alicyclic epoxy compounds, or two or more. Among the bifunctional alicyclic epoxy compounds, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate may be used.

[0049] The alicyclic epoxy compound may be included in amounts of 30 to 80 parts by weight, for example, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80 parts by weight, or 40 to 60 parts by weight, per 100 parts by weight of the total amount of the curable compound, for example, (A) epoxy compound and (B) (meth)acrylic compound. By satisfying this range, the effect of increasing the crosslinking density can be achieved.

[0050] Aliphatic epoxy compounds have the characteristic of having a long induction period after the epoxy ring is protonated by a cation, followed by stabilization due to hydrogen bonding with adjacent oxygen atoms. After this long induction period, the aliphatic epoxy compounds undergo post-reaction. This characteristic allows for effects such as increased peel strength and improved reliability in high-temperature and high-humidity environments.

[0051] In one embodiment, the aliphatic epoxy compound may be a bifunctional aliphatic epoxy compound, that is, a diglycidyl ether compound. By using a diglycidyl ether compound, the effects of the present invention relating to the barrier layer composition can be realized more easily.

[0052] For example, the aliphatic epoxy compound may include one or more diglycidyl ether compounds having a substituted or unsubstituted, linear or branched, alkylene group backbone with 3 or more carbon atoms, or substituted or unsubstituted diglycidyl ether compounds having ethylene oxide or propylene oxide in the molecule. Here, "substituted" means that one or more hydrogen atoms in the functional group are substituted with an alkyl group having 1 to 5 carbon atoms. Preferably, as the aliphatic epoxy compound, a substituted or unsubstituted, linear or branched, diglycidyl ether compound having a alkylene group backbone with 3 or more carbon atoms can be used, thereby making it easier to achieve the effects of the present invention compared to diglycidyl ether compounds having ethylene oxide or propylene oxide in the molecule.

[0053] Diglycidyl ether compounds having a substituted or unsubstituted, linear or branched alkylene group backbone with three or more carbon atoms can easily achieve the effects of the present invention because the linear alkylene group backbone with three or more carbon atoms provides a reaction-delaying effect. Here, "number of carbon atoms" refers only to the number of carbon atoms contained in the backbone of the linear or branched alkylene group.

[0054] Diglycidyl ether compounds having substituted or unsubstituted linear or branched alkylene groups with 3 or more carbon atoms can have linear or branched alkylene groups with 3 or more carbon atoms, preferably 3 to 10, and more preferably 3 to 6.

[0055] For example, the diglycidyl ether compound may be one or more of 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, and neopentyl glycol diglycidyl ether. Preferably, the diglycidyl ether compound may be one or more of 1,4-butanediol diglycidyl ether and neopentyl glycol diglycidyl ether.

[0056] Diglycidyl ether compounds having ethylene oxide or propylene oxide in their molecule can more easily realize the effects of the present invention because two or more ethylene oxides or propylene oxides in the molecule provide a reaction-delaying effect.

[0057] Diglycidyl ether compounds having two or more ethylene oxide or propylene oxide molecules are preferably diglycidyl ether compounds having 2 to 10 ethylene oxide or propylene oxide molecules. For example, the diglycidyl ether compound may be one or more of polyethylene glycol diglycidyl ether or polypropylene glycol diglycidyl ether.

[0058] Aliphatic epoxy compounds may be included in amounts of 20 to 60 parts by weight, for example, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 parts by weight, or 30 to 50 parts by weight, per 100 parts by weight of the total amount of curable compounds, such as (A) epoxy compounds and (B) (meth)acrylic compounds. By satisfying this range, the effect of increasing the adhesion to the substrate can be achieved.

[0059] (B) (meth)acrylic compounds (B) The (meth)acrylic compound may be included in an amount of 30 to 50 parts by weight per 100 parts by weight of the curable compound. Meeting this range facilitates improvements in adhesion, reliability, and compatibility. For example, the (meth)acrylic compound may be included in amounts of 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50 parts by weight, and 30 to 40 parts by weight.

[0060] (B) (Meth)acrylic compounds have a faster curing rate than epoxy compounds during photoradical polymerization reactions, which can increase the curing rate of barrier layer compositions and improve process stability. In addition, (meth)acrylic compounds have a low affinity for iodine and can not affect iodine decolorization.

[0061] (B) (meth)acrylic compounds include carboxyl group-containing (meth)acrylic compounds.

[0062] Carboxyl group-containing (meth)acrylic compounds can achieve iodine elution prevention in the barrier layer and decolorization prevention in the polarizer by reacting with the metal chelating crosslinking agent described below. The carboxyl group-containing (meth)acrylic compounds polymerize during the photocuring process of the barrier layer composition to form a first polymer network. The first polymer network has exposed carboxyl groups. The carboxyl groups can undergo an additional crosslinking reaction by reacting with the metal chelating crosslinking agent described below to form a second polymer network. The second polymer network has a denser and stronger structure than the first polymer network. It is believed that the formation of this second polymer network can increase the cohesive forces of the barrier layer, such as modulus and creep, while maintaining the peeling force of the barrier layer on the polarizer, thereby preventing iodine elution from the polarizer. However, the present invention is not limited to this mechanism.

[0063] A carboxyl group-containing (meth)acrylic compound may also be a compound having one or more carboxyl groups and one or more (meth)acrylic groups. For example, a carboxyl group-containing (meth)acrylic compound can be represented by the following formula 1.

[0064] [ka]

[0065] In Equation 1, L 11This is a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms. n is either 0 or 1. R 1 It is either a hydrogen atom or a methyl group.

[0066] For example, a carboxyl group-containing (meth)acrylic compound may contain one or more carboxyethyl (meth)acrylates, including (meth)acrylic acid and 2-carboxyethyl (meth)acrylate.

[0067] The carboxyl group-containing (meth)acrylic compound may be included in 1 to 10 parts by weight, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 parts by weight, or 2 to 5 parts by weight, per 100 parts by weight of (meth)acrylic compound (B). By satisfying this range, the effect of increasing the degree of crosslinking can be achieved.

[0068] The carboxyl group-containing (meth)acrylic compound may be included in 1 to 10 parts by weight, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 parts by weight and 2 to 5 parts by weight, per 100 parts by weight of the total amount of the curable compound, for example, (A) epoxy compound and (B) (meth)acrylic compound.

[0069] (B) The (meth)acrylic compound may further contain a carboxyl group-free (meth)acrylic compound in addition to the carboxyl group-containing (meth)acrylic compound.

[0070] Carboxyl group-free (meth)acrylic compounds may contain one or more monofunctional (meth)acrylates or difunctional (meth)acrylates.

[0071] Carboxyl group-free (meth)acrylic compounds may contain one or more aromatic group-containing (meth)acrylates and aromatic group-free (meth)acrylates.

[0072] In one embodiment, the carboxyl group-free (meth)acrylic compound may include an aromatic group-containing monofunctional (meth)acrylate.

[0073] (Meth)acrylates having aromatic functional groups may include, for example, one or more compounds of the following formula 2. [Formula 2] CH2=CR 2 -C(=O)-O-(-CH2-)sR 3

[0074] In equation 2, R 2 is a hydrogen or methyl group, and s is an integer between 0 and 10. R 3 This is a substituted or unsubstituted aryl group having 6 to 50 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 50 carbon atoms.

[0075] Here, "substitution" means that one or more hydrogen atoms of a functional group are replaced by an alkyl group having 1 to 10 carbon atoms.

[0076] Preferably, the (meth)acrylate having an aromatic functional group may include one or more benzyl (meth)acrylate and phenoxyethyl (meth)acrylate.

[0077] In one embodiment, the carboxyl group-free (meth)acrylic compound may include a difunctional (meth)acrylate having an alkylene glycol group. A polarizing plate containing a barrier layer formed from a composition that does not include a difunctional (meth)acrylate having an alkylene glycol group may experience problems during the crosslinking reaction.

[0078] A monofunctional (meth)acrylic compound, such as a (meth)acrylate having an aromatic functional group, may be included in 10 to 60 parts by weight per 100 parts by weight of (B)(meth)acrylic compound, for example, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 parts by weight, 20 to 60 parts by weight, or 20 to 50 parts by weight. By meeting this range, adhesive strength, reliability, and compatibility can be easily improved.

[0079] The alkylene glycol group may also be ethylene oxide or propylene oxide.

[0080] Alkylene glycol groups may be present in the monofunctional (meth)acrylic compound in a quantity of 1 or more, for example, 2 or more, or 2 to 5. By satisfying this range, the effects of the present invention can be more easily achieved.

[0081] For example, the difunctional (meth)acrylate having an alkylene glycol group may be one or more of diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, and tripropylene glycol di(meth)acrylate. Preferably, the difunctional (meth)acrylate having an alkylene glycol group may be one or more of dipropylene glycol di(meth)acrylate and tripropylene glycol di(meth)acrylate.

[0082] A bifunctional (meth)acrylic compound, such as a bifunctional (meth)acrylate having an alkylene glycol group, may be included in 5 to 50 parts by weight, preferably 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50 parts by weight, 5 to 30 parts by weight, or 5 to 25 parts by weight per 100 parts by weight of the curable compound. By satisfying this range, the reaction rate of the (meth)acrylic compound is increased to promote faster curing, and the problem of interfacial delamination due to excessively high shrinkage force caused by an overly fast reaction rate can be prevented.

[0083] A difunctional (meth)acrylic compound, such as a difunctional (meth)acrylate having an alkylene glycol group, may be included in 10 to 60 parts by weight per 100 parts by weight of (B)(meth)acrylic compound, for example, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 parts by weight, 20 to 60 parts by weight, or 20 to 50 parts by weight. By meeting this range, adhesive strength, reliability, and compatibility can be easily improved.

[0084] In one embodiment, the carboxyl group-free (meth)acrylic compound may be included in an amount of 1 to 10 parts by weight, for example, 2 to 5 parts by weight, per 100 parts by weight of (B) (meth)acrylic compound. The carboxyl group-free (meth)acrylic compound may be included in an amount of 1 to 10 parts by weight, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 parts by weight, or 2 to 5 parts by weight, per 100 parts by weight of the total of the curable compound, for example, (A) epoxy compound and (B) (meth)acrylic compound.

[0085] Photoinitiator The photoinitiator comprises a mixture of a photoacid generator and a photosensitizer.

[0086] The photoinitiator may be included in an amount of 1 to 15 parts by weight, preferably 1 to 10 parts by weight, per 100 parts by weight of the curable compound. By keeping within this range, the problem of the barrier layer composition remaining uncured can be prevented, and the problem of reduced light transmittance of the adhesive layer due to excessive use and remaining residue can be prevented.

[0087] The photosensitizer may be a cyclohexylphenyl ketone, a thioxanthone, or the like.

[0088] The photosensitizer may be included in an amount of 0.5 to 10 parts by weight, for example, 1 to 6 parts by weight, per 100 parts by weight of the curable compound. By satisfying this range, the barrier layer composition can be sufficiently cured, and problems such as reduced adhesion and photosensitizer bleed-out can be prevented.

[0089] Photoacid generators can contain onium ions, which are cations and anions, and onium salts. Specific examples of onium ions include diphenyliodonium, 4-methoxydiphenyliodonium, bis(4-methylphenyl)iodonium, bis(4-tart-butylphenyl)iodonium, bis(dodecylphenyl)iodonium, diaryliodoniums such as (4-methylphenyl)[(4-(2-methylpropyl)phenyl)iodonium, triphenylsulfonium, diphenyl-4-thiophenoxyphenylsulfonium, triarylsulfoniums such as diphenyl-4-(phenylthio)phenylsulfonium, bis[4-(diphenylsulfonio)-phenyl]sulfide, bis[4-(di(4-(2-hydroxyethyl)phenyl)sulfonio)-phenyl]sulfide, 5-2,4-(cyclopentadienyl)[1,2,3,4,5,6-η]-(methylethyl)-benzene]-iron(1 + Examples of anions include tetrafluoroborate (BF4). -), hexafluorophosphate (PF6 - ), hexafluoroantimonate (SbF6 - ), hexafluoroarsenate (AsF6 - ), hexachloroantimonate (SbCl6 - ) and the like can be mentioned.

[0090] The photoacid generator may be contained in an amount of 0.5 parts by weight to 10 parts by weight, for example, 1 part by weight to 6 parts by weight, based on 100 parts by weight of the curable compound. By satisfying this range, the composition for the barrier layer can be sufficiently cured, and problems such as a decrease in adhesive strength and bleed-out of the photoacid generator can be prevented.

[0091] Metal chelating crosslinking agents The metal chelate crosslinking agent can form a second polymer network by undergoing a crosslinking reaction with the carboxyl groups of the first polymer network.

[0092] As the metal chelate crosslinking agent, a normal thermosetting crosslinking agent can be used. For example, a crosslinking agent containing a metal such as aluminum, titanium, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, zirconium, etc. may also be used.

[0093] For example, the crosslinking agent can contain one or more of aluminum ethyl acetoacetate diisopropylate, aluminum tris(ethyl acetoacetate), alkyl acetoacetate aluminum diisopropylate, aluminum isopropylate, mono-sec-butoxy aluminum diisopropylate, aluminum sec-butyrate, aluminum ethoxide, tetraisopropyl titanate, tetra-n-butyl titanate, butyl titanate dimer, titanium acetylacetonate, titanium octylene glycolate, titanium tetraacetylacetonate, titanium ethyl acetoacetate, polyhydroxy titanium stearate, aluminum acetylacetonate.

[0094] In particular, by using a metal chelating crosslinking agent having an acetylacetonate group, when forming a barrier layer from the barrier layer composition, the acetylacetonate group volatilizes from the crosslinking agent, increasing the curing rate of the (meth)acrylic compound. This shortens the curing time of the barrier layer, thereby more effectively shortening the process.

[0095] The metal chelating crosslinking agent may be included in an amount of 0.1 to 2 parts by weight per 100 parts by weight of the (meth)acrylic compound (B). By satisfying this range, an effect of preventing iodine elution can be achieved, and the phenomenon of reduced light transmittance of the barrier layer due to residual iodine can be prevented.

[0096] The metal chelating crosslinking agent may be included in an amount of 0.1 to 2 parts by weight per 100 parts by weight of the curable compound, for example, (A) epoxy compound and (B) (meth)acrylic compound. By satisfying this range, an iodine elution prevention effect is achieved, and the phenomenon of reduced light transmittance of the barrier layer due to residual iodine can be prevented.

[0097] For example, the metal chelating crosslinking agent may be included in an amount of 0.5 to 1.5 parts by weight per 100 parts by weight of the curable compound, for example, (A) an epoxy compound and (B) a (meth)acrylic compound. By satisfying this range, the barrier layer composition can be made more usable and its storage stability improved, thereby improving the productivity of the barrier layer.

[0098] The barrier layer composition can be manufactured by mixing a curable compound, a photoinitiator, and a metal chelating crosslinking agent. The barrier layer composition may be solvent-free, or it may further contain a solvent to improve its applicability (coating properties).

[0099] The barrier layer composition may further contain, to the extent that it does not impair the effects of the present invention, antioxidants, ultraviolet absorbers, ionic conductive agents, conductive metal oxide fine particles and other conductivity-imparting additives, light-diffusing additives, viscosity modifiers, and the like.

[0100] The following describes how to form the barrier layer.

[0101] A barrier layer coating film containing a first polymer network is produced by applying a barrier layer composition to a polarizer or a phase difference layer described below to a predetermined thickness and photocuring it. The barrier layer coating film further comprises (A) a photocured epoxy compound. Subsequently, the barrier layer coating film undergoes maturation, during which a crosslinking reaction occurs between carboxyl groups and metal chelating crosslinking agents, forming a barrier layer. Maturation may be carried out by internal heat generated during photocuring. The maturation time can also be shortened by additional heat treatment.

[0102] The barrier layer may have a thickness of 10 nm to 500 nm, for example, 50 nm to 200 nm. By meeting this range, the polarizing plate can be made thinner.

[0103] polarizer The polarizer may include conventional polarizers known to those skilled in the art. For example, the polarizer may be made of a polyvinyl alcohol (PVA) resin film or a polypropylene (PP) resin film. Specifically, the polarizer may be a polyvinyl alcohol-based polarizer in which one or more dichroic substances such as iodine and dichroic dyes are adsorbed onto a polyvinyl alcohol resin film.

[0104] The degree of saponification of the polyvinyl alcohol-based resin film may be 85% to 100%, specifically 98% to 100%. The degree of polymerization of the polyvinyl alcohol-based resin film may also be 1,000 to 10,000, specifically 1,500 to 10,000. Polarizers can be manufactured to satisfy these degrees of saponification and polymerization. Polarizers can be manufactured by conventional methods known to those skilled in the art.

[0105] The thickness of the polarizer can be 5 μm to 30 μm, specifically 5 μm to 25 μm. By meeting this range, the polarizer can be used in a polarizing plate, enabling the polarizing plate to be made thinner.

[0106] protective layer The polarizing plate may further include one or more protective layers.

[0107] The protective layer can be formed on at least one surface of the polarizer to protect the polarizer or to provide additional functionality to the polarizer.

[0108] The protective layer may include one or more optically transparent protective films and protective coating layers.

[0109] If the protective layer is a protective film, the protective layer may include a protective film formed from an optically transparent resin. The protective film can be formed by melting and extruding the resin. A stretching step may be added if necessary. The resin may include one or more cellulose ester resins including triacetylcellulose, cyclic polyolefin resins including cyclic polyolefin polymers (COP), polycarbonate resins, polyester resins including polyethylene terephthalate (PET), polyethersulfone resins, polysulfone resins, polyamide resins, polyimide resins, acyclic polyolefin resins, polyacrylate resins including polymethyl methacrylate resins, polyvinyl alcohol resins, polyvinyl chloride resins, and polyvinylidene chloride resins. Preferably, the protective film may be a film formed from a cyclic polyolefin resin including cyclic polyolefins.

[0110] If the protective layer is a protective coating layer, it can improve good adhesion to the polarizer, transparency, mechanical strength, thermal stability, moisture barrier properties, and durability. In one embodiment, the protective coating layer for the protective layer may be formed of an active energy ray curable resin composition comprising an active energy ray curable compound and a polymerization initiator.

[0111] The active energy ray curable compound may include one or more cationic curable compounds, radical curable compounds, urethane resins, and silicone resins. The cationic curable compound may be an epoxy compound having at least one epoxy group in its molecule, or an oxetane compound having at least one oxetane ring in its molecule. The radical curable compound may be a (meth)acrylic compound having at least one (meth)acryloyloxy group in its molecule.

[0112] The protective layer may further contain additives known to those skilled in the art, in addition to the optically transparent resin or active energy ray curable compound described above. The additives may include antioxidants, UV absorbers, ionic conductive agents, conductive metal oxide nanoparticles or other conductive additives, light-diffusing additives, viscosity modifiers, and the like.

[0113] The thickness of the protective layer is 5 μm to 200 μm, specifically 30 μm to 120 μm. For protective films, it may be 50 μm to 100 μm, and for protective coating layers, it may be 5 μm to 50 μm. Meeting this range allows the protective layer to be used in optical display devices.

[0114] The protective layer may include a functional coating layer formed on at least one surface, or may be surface-treated. The functional coating layer may be, but is not limited to, a hard coating layer, a fingerprint-resistant layer, an anti-reflective layer, a low-reflection layer, an ultra-low-reflection layer, an anti-glare layer, etc. The surface treatment may be, but is not limited to, a corona treatment, etc.

[0115] The protective layer can be bonded to a polarizer or other adherend by an adhesive layer. The adhesive layer can be formed with a water-based adhesive or a photocurable adhesive, but is not limited to these. Water-based adhesives and photocurable adhesives can be used appropriately with reference to matters known to those skilled in the art.

[0116] When the protective layer is laminated onto the polarizer opposite the adhesive layer, the protective layer can also be called the upper protective layer.

[0117] retardation layer A polarizing plate may further include one or more phase difference layers. The phase difference layers may be present in the polarizing plate in one or more or two or more layers.

[0118] The phase difference layer can improve screen quality by preventing reflection from external light and converting linearly polarized light emitted after passing through the polarizer into circularly polarized light.

[0119] In one embodiment, the phase difference layer can have an in-plane phase difference (Re) at a wavelength of 550 nm of 225 nm to 350 nm, specifically 225 nm to 300 nm, for example, a λ / 2 phase difference (first phase difference layer). By satisfying this range, the reflectance to ambient light can be reduced and screen quality can be improved.

[0120] In another embodiment, the phase difference layer may have an in-plane phase difference (Re) at a wavelength of 550 nm of 100 nm to 220 nm, specifically 100 nm to 180 nm, for example, a λ / 4 phase difference (second phase difference layer). By satisfying this range, the reflectance to ambient light can be reduced and screen quality can be improved.

[0121] In another embodiment, the phase difference layer may be a stack of a first phase difference layer and a second phase difference layer.

[0122] In one embodiment, the phase difference layer can exhibit inverse wavelength dispersion.

[0123] The thickness of the phase difference layer can be 0.01 μm to 30 μm, for example, 1 μm to 10 μm. By satisfying this range, the polarizing plate can be made thinner and the target phase difference can be achieved.

[0124] The phase difference layer may be a film or a coating layer. Preferably, the phase difference layer may be a coating layer in order to make the polarizing plate thinner.

[0125] The phase difference layer may be a liquid crystal layer or a non-liquid crystal layer.

[0126] The phase difference layer in film form can be manufactured from resins commonly known to those skilled in the art, and may include, for example, one or more cellulose ester resins containing triacetylcellulose (TAC), cyclic polyolefin (COP) resins containing amorphous cyclic polyolefins, polycarbonate resins, polyester resins containing polyethylene terephthalate (PET), polyethersulfone resins, polysulfone resins, polyamide resins, polyimide resins, acyclic polyolefin resins, polyacrylate resins containing polymethyl methacrylate resins, polyvinyl alcohol resins, polyvinyl chloride resins, and polyvinylidene chloride resins.

[0127] The phase difference layer in the form of a coating layer is non-liquid crystallinity and may include a coating layer formed from a thermosetting or active energy ray curable composition, or a coating layer formed from a liquid crystal composition.

[0128] In one embodiment, the phase difference layer is either a non-liquid crystal layer or a liquid crystal layer. Preferably, the phase difference layer is a liquid crystal layer, which allows the polarizing plate to be made thinner.

[0129] For example, the liquid crystal layer can be formed from a composition containing a liquid crystalline compound having one or more aromatic functional groups and alicyclic functional groups. In one embodiment, the liquid crystalline compound may be a polymer, oligomer, or monomer containing a unit composed of an aromatic ring and a polymerizable functional group that can impart liquid crystallinity. The polymerizable functional group may include a (meth)acryloyl group, an epoxy group, or a vinyl ether group, and can be cured by heat or light to increase the strength of the liquid crystal phase difference layer.

[0130] The barrier layer composition can be formed from a composition containing the above-mentioned aromatic-containing liquid crystal compound. The barrier layer composition may further contain additives such as leveling agents, polymerization initiators, orientation aids, heat stabilizers, lubricants, plasticizers, and antistatic agents, the specific types of which can be found by referring to those skilled in the art.

[0131] adhesive layer A polarizing plate may contain one or more adhesive layers. The adhesive layers may consist of one or more, or two or more, layers within the polarizing plate.

[0132] The adhesive layer can adhere the barrier layer to the phase difference layer, or to the barrier layer to the protective layer.

[0133] In one embodiment, the adhesive layer may be a pressure-sensitive adhesive (PSA). For example, the pressure-sensitive adhesive layer may include a cured product of a composition containing an adhesive resin and a curing agent.

[0134] Figures 1 and 2 are cross-sectional views of a polarizing plate related to one of the instances of negligence in implementation.

[0135] Referring to Figure 1, the polarizing plate may include a polarizer 100, a protective layer 200 laminated on the upper surface of the polarizer, and a barrier layer 300 and a first phase difference layer 400 sequentially laminated on the lower surface of the polarizer.

[0136] Referring to Figure 2, the polarizing plate may include a polarizer 100, a protective layer 200 laminated on the upper surface of the polarizer, a barrier layer 300 sequentially laminated on the lower surface of the polarizer, a second phase difference layer 500, an adhesive layer 600, and a first phase difference layer 400.

[0137] Although not shown in Figures 1 and 2, polarizers may further include one or more of the polarizer protective films, anti-reflective films, phase difference films (liquid crystal layer or non-liquid crystal layer), and adhesive films commonly used in polarizers.

[0138] An optical display device according to one embodiment of the present invention includes the polarizing plate of the present invention. For example, the optical display device may be an light-emitting device device equipped with a light-emitting element, a liquid crystal display device, and the like. [Examples]

[0139] The configuration and operation of the present invention will be described in more detail below through examples of the present invention. However, the following examples are provided to aid in understanding the present invention, and the scope of the present invention is not limited to these examples.

[0140] Example 1 (1) Preparation of barrier layer composition A curable compound was prepared by mixing alicyclic epoxy compounds, aliphatic epoxy compounds, (meth)acrylate compounds, and (meth)acrylic acid according to the content described in Table 1 below.

[0141] 100 parts by weight of the prepared curable compound was mixed with 4 parts by weight of a photoacid generator (Irgacure250) and 1 part by weight of a photosensitizer (thioxanthone-based, DETX-S) to prepare a solvent-free barrier layer composition.

[0142] (2) Fabrication of polarizing plates A polyvinyl alcohol-based film (TS#20, manufactured by Kuraray Co., Ltd., thickness: 20 μm) was immersed in a 0.3% potassium iodide aqueous solution to dye it, and then the film was MD-stretched at a machine direction (MD) uniaxial stretching ratio of 5.0. The stretched polyvinyl alcohol-based film was immersed in a 3% boric acid aqueous solution and a 2% potassium iodide aqueous solution to correct its hue, and then dried at 50°C for 4 minutes to produce a polarizer (light transmittance: 45%, thickness: 7 μm).

[0143] As the upper polarizer protective film, a cycloolefin polymer film (manufactured by Zeon, thickness: 25 μm) with a hard coating layer formed on its upper surface was prepared, and the underside of the film was corona treated using a corona treatment machine (manufactured by AFS) at a speed of 10 mpm and an output of 1000 W.

[0144] A triacetylcellulose film (Konica Corporation, normal TAC, thickness: 40 μm) was prepared as a protective film for the lower polarizer without saponification treatment.

[0145] A polyvinyl alcohol-based resin (Mitsubishi Chemical Corporation's Z200, containing acetoacetyl groups, average degree of polymerization: 1200, degree of saponification: 98.5%, degree of acetoacetylation: 5 moles) was dissolved in water at 95°C for 60 minutes and then cooled completely to room temperature to prepare an aqueous solution of the polyvinyl alcohol-based resin. Subsequently, 0.1 parts by weight of Zircosol-ZN (Daiichi Rare Elements Chemical Industry Co., Ltd.), a zirconium-containing crosslinking agent, was added to 100 parts by weight of the aqueous polyvinyl alcohol-based resin solution and mixed to prepare a water-based adhesive.

[0146] A water-based adhesive was applied to both sides of the polarizer to a predetermined thickness. A protective film for the upper polarizer was bonded to one side, and a triacetylcellulose film was bonded to the other side simultaneously. After drying at 80°C for 3 minutes, the triacetylcellulose film was removed to expose the other side of the polarizer.

[0147] A λ / 2 liquid crystal phase difference film (a laminate of a DNP λ / 2 liquid crystal phase difference layer (thickness: 2 μm) and a base film) was prepared. The λ / 2 liquid crystal phase difference layer side of the λ / 2 liquid crystal phase difference film was subjected to corona treatment using a corona treatment machine (AFS) at a speed of 10 mpm and an output of 1000 W.

[0148] In a λ / 2 liquid crystal phase difference film, a barrier layer composition prepared for this purpose is applied to the λ / 2 liquid crystal phase difference layer to a thickness of approximately 3 μm. After aligning it with another side of the polarizer, a metal halide lamp is positioned on the substrate film side of the λ / 2 liquid crystal phase difference film, and a UVA-based radiation of approximately 1000 mJ / cm² is applied. 2 The barrier layer composition was cured by irradiating it with light at a light intensity to form a barrier layer, and then the base film was removed.

[0149] A λ / 4 liquid crystal phase difference film (a laminate of a DNP λ / 4 liquid crystal phase difference layer (thickness: 1 μm) and a base film) was prepared. The λ / 4 liquid crystal phase difference layer side of the λ / 4 liquid crystal phase difference film was subjected to corona treatment using a corona treatment machine (AFS) at a speed of 10 mpm and an output of 1000 W.

[0150] The λ / 2 liquid crystal phase difference layer was subjected to corona treatment using a corona treatment machine (manufactured by AFS) at a speed of 10 mpm and an output of 1000 W.

[0151] The prepared barrier layer composition is applied to the λ / 4 liquid crystal phase difference layer to a thickness of approximately 3 μm, bonded to the λ / 2 liquid crystal phase difference layer, and a metal halide lamp is positioned on the substrate film side of the λ / 4 liquid crystal phase difference film, with a UVA standard of approximately 1000 mJ / cm². 2 The barrier layer composition was cured by irradiating it with light at a light intensity to form a barrier layer, and the base film was removed to create a polarizing plate in which the upper polarizer protective film - water-based adhesive layer - polarizer - barrier layer - λ / 2 liquid crystal phase difference layer - barrier layer - λ / 4 liquid crystal phase difference layer were laminated in that order.

[0152] The polarizing plates were fabricated at a temperature of 22°C to 25°C and a relative humidity of 20% to 60%.

[0153] Examples 2 to 10 and Comparative Examples 1 to 2 A polarizing plate was prepared using the same method as in Example 1, except that the content of each component was changed as shown in Table 1 below.

[0154] The polarizing plates manufactured in the examples and comparative examples are shown in Table 1 below, and their physical properties were evaluated according to Table 1.

[0155] (1) Change in corrosion resistance after high temperature and high humidity treatment The polarizing plates prepared in the examples and comparative examples were cut to a length of 65 mm and a width of 25 mm, and bonded to the ITO surface of an ITO film (thickness: 125 μm, 60 Ω) via an acrylic adhesive layer. After applying silver paste to the bonded samples, they were dried at 40°C for 1 hour and left at room temperature for 1 hour to prepare the samples shown in Figure 3. As shown in Figure 3, the initial resistance (R0) of the samples was measured using a two-terminal multimeter at six measurement points 33 formed by the ITO film 31, polarizing plate 32, and silver paste. Subsequently, the samples were placed in a chamber at a temperature of 60°C and relative humidity of 95%, left for 500 hours, and then removed. After being left at 25°C for 1 hour, the resistance (R1) was measured in the same manner. The change in resistance |R1-R0| was calculated. A lower change in resistance means that the barrier layer can provide a barrier effect against iodine leached from the polarizer.

[0156] (2) Decolorization after high temperature and high humidity treatment The polarizing plates prepared in the examples and comparative examples were cut into 50mm x 50mm squares at a 45° angle with respect to the absorption axis of the polarizer, and the samples were prepared by attaching them to a glass plate via an acrylic adhesive layer. The samples were placed in a chamber at 60°C and 95% relative humidity, left for 500 hours, and then removed. Subsequently, as shown by arrow 42 in Figure 4, the iodine discoloration was measured along the diagonal direction of sample 41, and the results were classified as follows: ○: no discoloration, △: partial discoloration, ×: complete discoloration.

[0157] (3) Available time The initial viscosity (V0) of 1 g of the barrier layer composition prepared in the examples and comparative examples was measured at 25°C using a viscometer. After leaving this composition at 25°C for 4 hours, the viscosity (V1) was measured in the same manner. The viscosity change rate ((V1-V0) / V0x100) was calculated, and it was evaluated as follows: ○ if the viscosity change rate was 0% or more and 30% or less, △ if it was more than 30% and 50% or less, and X if it was more than 50%.

[0158] [Table 1]

[0159] The symbols in Table 1 are as follows: A: Alicyclic epoxy compound, CELLOXIDE2021P B: Aliphatic epoxy compound, 1,4-butanediol diglycidyl ether C: Dipropylene glycol diacrylate D: Aromatic (meth)acrylic compounds, 2-phenoxyethyl acrylate E: Methacrylic acid F: Metal chelate crosslinking agent F1: Acetylacetonate aluminum(III) (AlACA, manufactured by TCI) F2: Acetylacetonate Titanium (IV) (TiACA, manufactured by TCI)

[0160] As shown in Table 1, the polarizing plate of the present invention has no protective layer on at least one surface of the polarizer, making it possible to make the polarizing plate thinner. The polarizing plate of the present invention can prevent the elution of dichroic substances from the polarizer after being left in high temperature and high humidity conditions for a long period of time, thus preventing corrosion of panels and the like. The polarizing plate of the present invention does not decolorize the polarizer after being left in high temperature and high humidity conditions for a long period of time, thus improving reliability and durability. The polarizing plate of the present invention includes a barrier layer formed of a barrier layer composition that has a long usable time and excellent storage stability, so it can be said that the polarizing plate has excellent productivity.

[0161] Simple modifications or alterations of the present invention can be readily carried out by a person with ordinary skill in the art, and all such modifications or alterations can be considered to fall within the scope of the present invention.

Claims

1. The polarizer comprises a polarizer and a barrier layer laminated on one surface of the polarizer, The barrier layer comprises a curable compound including an epoxy compound and a (meth)acrylic compound, a photoinitiator, and a metal chelating crosslinking agent, wherein the (meth)acrylic compound includes a cured product of a barrier layer composition containing a carboxyl group-containing (meth)acrylic compound, and is a polarizing plate.

2. The polarizing plate according to claim 1, wherein the metal chelating crosslinking agent is a thermosetting crosslinking agent.

3. The polarizing plate according to claim 1, wherein the metal chelating crosslinking agent is aluminum, titanium, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, or zirconium.

4. The polarizing plate according to claim 1, wherein the metal chelate crosslinking agent is contained in an amount of 0.1 to 2 parts by weight per 100 parts by weight of the curable compound.

5. The polarizing plate according to claim 1, wherein the metal chelating crosslinking agent is contained in an amount of 0.1 to 2 parts by weight per 100 parts by weight of the (meth)acrylic compound.

6. The polarizing plate according to claim 1, wherein the metal chelating crosslinking agent is contained in an amount of 0.5 to 1.5 parts by weight per 100 parts by weight of the curable compound.

7. The carboxyl group-containing (meth)acrylic compound is represented by the following formula 1, 【Chemistry 1】 In the above formula 1, L １１ This is a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms. n is either 0 or 1, R １ The polarizing plate according to claim 1, wherein is a hydrogen or methyl group.

8. The polarizing plate according to claim 7, wherein the carboxyl group-containing (meth)acrylic compound comprises one or more (meth)acrylic acid and carboxyethyl (meth)acrylate.

9. The polarizing plate according to claim 1, wherein the carboxyl group-containing (meth)acrylic compound is contained in an amount of 1 to 10 parts by weight per 100 parts by weight of the curable compound.

10. The polarizing plate according to claim 1, further comprising a carboxyl group-free (meth)acrylic compound.

11. The polarizing plate according to claim 10, wherein the carboxyl group-free (meth)acrylic compound comprises one or more aromatic group-containing monofunctional (meth)acrylates and difunctional (meth)acrylates having alkylene glycol groups.

12. The polarizing plate according to claim 1, wherein the epoxy compound comprises a mixture of an alicyclic epoxy compound and an aliphatic epoxy compound.

13. The polarizing plate according to claim 12, wherein the aliphatic epoxy compound comprises a diglycidyl ether compound.

14. The polarizing plate according to claim 1, further comprising a liquid crystal phase difference layer.

15. A display device comprising a polarizing plate according to any one of claims 1 to 14.

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