Polarizing plate and image display device

Abstract

[The technical problem to be solved] The objective of this invention is to provide a polarizing plate that suppresses the decrease in transmittance under high-temperature conditions. Technical means to solve the problem The present invention provides a polarizing plate having, in sequence, a polarizing element having a dichroic pigment adsorbed and aligned on a polyvinyl alcohol resin layer, a transparent protective film, and a phase retardation layer. The polarizing element and the transparent protective film are bonded together by a first adhesive layer formed by a first adhesive containing a urea compound, and the transparent protective film and the phase retardation layer are bonded together by a second adhesive layer formed by a second adhesive of an active energy line curing type. The urea compound is selected from at least one of the group consisting of urea, urea derivatives, thiourea, and thiourea derivatives. The phase retardation layer has a curing layer of a polymerizable liquid crystal compound.

Description

Polarizing plate and image display device This invention relates to a polarizing plate and an image display device. Circular polarizers with polarizing elements and retardation layers are widely used in image display devices such as liquid crystal displays (LCDs) and organic EL displays. With the trend towards thinner image display devices, the requirements for thinner circular polarizers have also increased. Patent Document 1 discloses an optical film that serves as a thin and efficiently manufactured retardation plate, comprising a positive A plate and a positive C plate, which are composed of a cured material containing a liquid crystal compound. [Previous Technical Documents] [Patent Literature] Patent document 1: Japanese Patent Application Publication No. 2016-053709. However, polarizing plates formed by bonding a phase retardation layer containing a polymeric liquid crystal compound to a hardened layer using an active energy line curing adhesive exhibit a significant decrease in transmittance at high temperatures. The present invention aims to provide a polarizing plate that suppresses transmittance reduction at high temperatures, and an image display device using the polarizing plate. This invention relates to the following exemplary items. [1] A polarizing plate, comprising, in sequence, a polarizing element having a dichroic pigment adsorbed and aligned on a polyvinyl alcohol resin layer, a transparent protective film, and a phase retardation layer. The aforementioned polarizing element and the aforementioned transparent protective film are bonded together by a first adhesive layer formed by a first adhesive containing a urea compound. The aforementioned transparent protective film and the aforementioned phase retardation layer are bonded together using a second adhesive layer formed by an active energy line curing type second adhesive. The aforementioned urea compounds are selected from at least one of the group consisting of urea, urea derivatives, thiourea, and thiourea derivatives. The aforementioned phase retardation layer has a hardened layer of polymeric liquid crystal compound. [2] The polarizing plate as described in [1], wherein the aforementioned urea compound is selected from at least one urea compound in the group consisting of urea derivatives and thiourea derivatives. [3] The polarizing plate as described in [1] or [2], wherein the aforementioned first adhesive contains a polyvinyl alcohol resin. [4] A polarizing plate as described in any one of [1] to [3], wherein the aforementioned phase retardation layer is a hardened layer of two polymeric liquid crystal compounds in direct contact. [5] A polarizing plate as described in any one of [1] to [4], wherein the aforementioned phase difference layer has a positive C plate and a positive A plate. [6] A polarizing plate as described in any one of [1] to [5], wherein the aforementioned second adhesive contains a cationic polymeric compound. [7] A polarizing plate as described in any one of [1] to [6], wherein the aforementioned cationic polymeric compound contains at least one compound selected from the group consisting of alicyclic epoxy compounds and aliphatic epoxy compounds. [8] A polarizing plate as described in any one of [1] to [7], wherein the aforementioned transparent protective film is provided on both sides of the aforementioned polarizing element. [9] The polarizing plate as described in any one of [1] to [8], wherein the moisture content of the aforementioned polarizing plate is above the equilibrium moisture content at a temperature of 20°C and a relative humidity of 40% and below the equilibrium moisture content at a temperature of 20°C and a relative humidity of 60%.

[10] An image display device comprising a polarizing plate as described in any one of [1] to [9]. According to the present invention, a polarizing plate that suppresses the reduction of transmittance in high-temperature environments can be provided. Furthermore, by using the polarizing plate of the present invention, an image display device that suppresses the reduction of transmittance in high-temperature environments can be provided. [Polarizing plate] The polarizing plate of this invention sequentially comprises a polarizing element having a dichroic pigment adsorbed and aligned on a polyvinyl alcohol-based resin layer, a transparent protective film, and a phase retardation layer. The polarizing element and the transparent protective film are bonded together using a first adhesive layer formed by a first adhesive containing a urea-based compound. The transparent protective film and the phase retardation layer are bonded together using a second adhesive layer formed by a second adhesive belonging to the active energy line curing type. The polarizing plate of this invention can be a circular polarizing plate or an elliptical polarizing plate. The polarizing plate of this invention can improve high-temperature durability (suppress characteristic changes under high-temperature environments). For example, even when exposed to a high-temperature environment of 105°C for a long time, the polarizing plate of this invention can suppress the decrease in monomer transmittance. For example, even when exposed to a high-temperature environment of 105°C for 200 hours, the monomer transmittance can decrease by less than 5%. A polarizing plate can be disposed on the visual confirmation side surface of an image display panel and used in an image display device. A transparent component such as a front panel or touch panel can be disposed on the visual confirmation side of the image display device. To improve visual confirmation, a configuration (hereinafter referred to as "interlayer filling configuration") is often used where a solid layer (a layer other than the air layer, also referred to as "interlayer filler") fills the space between the polarizing plate and the transparent component. The interlayer filler is preferably a material with a refractive index close to that of the polarizing plate or the transparent component. The interlayer filler can suppress the decrease in visual confirmation caused by interface reflection, and pressure-sensitive adhesives or UV-curing adhesives are used to bond and fix the components together. However, it is known that the transmittance of individual components in image display devices using an interlayer filling configuration tends to decrease under high-temperature conditions. The polarizing plate of the present invention can suppress the decrease in transmittance even when assembled in an image display device with an interlayer filling configuration. A polarizing plate with significantly reduced transmittance was measured by Raman spectrometry at 1100 cm⁻¹. -1 Nearby (derived from =CC= bond) and 1500cm -1 The presence of peaks in the vicinity (originating from -C=C- bonds) suggests the formation of a polyene structure (-C=C). n - The polyene structure is speculated to be produced by the polyene formation of polyvinyl alcohol constituting the polarizing element through dehydration. <Polarizing element> A known polarizing element can be used in a polarizing element on which a dichroic dye is adsorbed and aligned to a layer containing polyvinyl alcohol (hereinafter also referred to as "PVA")-based resin (hereinafter also referred to as "PVA-based resin layer"). Examples of polarizing elements include an extended film obtained by dyeing a PVA-based resin film with a dichroic dye and then uniaxially stretching it; or an extended layer obtained by using a laminated film having a coating layer formed by coating a coating liquid containing a PVA-based resin on a substrate film, dyeing the coating layer with a dichroic dye, and then uniaxially stretching the laminated film. Stretching can be performed after dyeing with the dichroic dye, or it can be performed while dyeing, or it can be performed after stretching. PVA-based resins can be obtained by saponifying polyvinyl acetate-based resins. Besides polyvinyl acetate, which is a homopolymer of vinyl acetate, polyvinyl acetate-based resins can also include copolymers of vinyl acetate with other monomers that can be copolymerized with it. Other monomers that can be copolymerized with vinyl acetate include, for example, unsaturated carboxylic acid compounds, olefin compounds, vinyl ether compounds, unsaturated sulfonic acid compounds, and (meth)acrylamide compounds with ammonium groups. The degree of saponification of polyvinyl alcohol-based resins is typically about 85 mol% or more, preferably about 90 mol% or more, and more preferably about 99 mol% or more and 100 mol% or less. PVA resins can be modified, for example, into aldehyde-modified polyethylene formaldehyde, polyethylene acetal, and polyethylene butyral. The average degree of polymerization of polyvinyl alcohol (PVA) resins is preferably between 100 and 10,000, more preferably between 1,500 and 8,000, and even more preferably between 2,000 and 5,000. The average degree of polymerization of PVA resins can be determined according to JIS K 6726 (1994). When the average degree of polymerization is within the above range, there is a tendency for excellent polarization properties and film processability. Preferably, the PVA-based resin layer is formed from a PVA-based resin with a boron adsorption rate of 5.70% by mass or higher. That is, the boron adsorption rate of the PVA-based resin in the raw material stage before dyeing or stretching is 5.70% by mass or higher. By using this PVA-based resin, the transmittance is less likely to decrease even when exposed to a high-temperature environment of 105°C. It is more preferably 5.72% by mass or higher, and even more preferably 5.75% by mass, and most preferably 5.80% by mass or higher, when manufacturing polarizing elements. Furthermore, the boron adsorption rate of the PVA-based resin is preferably 10% by mass or lower. Using this PVA-based resin to manufacture polarizing elements prevents the boric acid concentration in the boric acid treatment bath from becoming high, shortens the boric acid treatment time, facilitates obtaining the desired polarizing element, and improves the productivity of polarizing elements. If the boron adsorption rate of the PVA-based resin is 10% by mass or lower, boron will appropriately enter the PVA-based resin layer, easily reducing the shrinkage force of the polarizing element. As a result, when assembled into an image display device, defects such as peeling between the front panel and other components and the polarizing plate are less likely to occur. Furthermore, if the boron adsorption rate of the PVA-based resin is 5.70% by mass or higher, the transmittance is less likely to decrease even when exposed to a high-temperature environment of 105°C, and as mentioned above, productivity can be improved. The boron adsorption rate of the PVA-based resin can be determined by the method described in the examples below. The thickness of the polarizing element is preferably 3μm to 35μm, more preferably 4μm to 30μm, and even more preferably 5μm to 25μm. When the thickness of the polarizing element is 35μm or less, the effect of polyolefin formation in the PVA-based resin on the reduction of optical properties under high-temperature conditions can be suppressed. When the thickness of the polarizing element is 3μm or more, it is easier to form a structure that achieves the desired optical properties. The thickness of the polarizing element can be controlled, for example, by selecting a PVA-based resin film and adjusting the elongation ratio. The polarizing element preferably contains a urea-based compound. In one embodiment, the polarizing element and the transparent protective film are bonded together by a first adhesive layer formed by a first adhesive containing a urea-based compound, so it is presumed that the polarizing element contains a portion of the urea-based compound transferred from the first adhesive layer. The urea-based compound can be added to the polarizing element during the manufacturing process. Having an adhesive layer containing a urea-based compound prevents the transmittance from easily decreasing even when the polarizing plate is exposed to a high-temperature environment. Furthermore, having an adhesive layer containing a urea-based compound suppresses the decrease in polarization even when the polarizing plate is exposed to a high-temperature environment. When two polarizing plates are arranged in a crossed polarizer configuration, light leakage (hereinafter also referred to as "crossing light leakage") is easily generated if the polarization of the polarizing plates decreases. However, according to the present invention, the polarization is not easily reduced even when exposed to a high-temperature environment, and crossing light leakage is easily suppressed. It is presumed that the polyolefination of the PVA-based resin is suppressed by the urea-based compound contained in the polarizing element. A preferred method for including urea-based compounds in polarizing elements is to impregnate a PVA-based resin layer with a processing solvent containing urea-based compounds. However, the processing solvent containing urea-based compounds can also be sprayed, dripped, or dropped onto the PVA-based resin layer. To include urea-based compounds in the polarizing element, they can be added during the manufacturing process of the polarizing element or added to the adhesive. The step of impregnating the PVA-based resin layer with a solvent containing urea compounds can be performed simultaneously with the swelling, stretching, dyeing, crosslinking, and washing steps in the polarizing element manufacturing method described later, or it can be performed separately from these steps. Preferably, the step of impregnating the PVA-based resin layer with urea compounds is performed after dyeing the PVA-based resin layer with iodine, and more preferably simultaneously with the crosslinking step after dyeing. This method results in minimal hue change, reducing the impact on the optical properties of the polarizing element. (Urea compounds) Urea compounds are selected from at least one of the group consisting of urea, urea derivatives, thiourea, and thiourea derivatives. Urea compounds can be used alone or in combination of two or more. Urea compounds include water-soluble compounds and water-poorly soluble compounds, both of which can be used. When using water-poorly soluble urea compounds in water-soluble adhesives, a dispersion method is preferably considered that does not cause an increase in haze after the adhesive layer is formed. (Urea derivatives) Urea derivatives are compounds in which at least one of the four hydrogen atoms of a urea molecule is substituted with a substituent. In this case, there are no particular restrictions on the substituent, but it is preferred to be a substituent formed by a carbon atom, a hydrogen atom, and an oxygen atom. Specific examples of urea derivatives include methylurea, ethylurea, propylurea, butylurea, isobutylurea, N-octadecylurea, 2-hydroxyethylurea, hydroxyurea, acetylurea, allylurea, 2-propynylurea, cyclohexylurea, phenylurea, 3-hydroxyphenylurea, (4-methoxyphenyl)urea, benzylurea, benzoylurea, o-tolylurea, and p-tolylurea. Examples of 2-substituted ureas include 1,1-dimethylurea, 1,3-dimethylurea, 1,1-diethylurea, 1,3-diethylurea, 1,3-bis(hydroxymethyl)urea, 1,3-tert-butylurea, 1,3-dicyclohexylurea, 1,3-diphenylurea, 1,3-bis(4-methoxyphenyl)urea, 1-acetyl-3-methylurea, 2-imidazolidinedione (ethyleneurea), and tetrahydro-2-pyrimidinone (acrylurea). Examples of 4-substituted ureas include tetramethylurea, 1,1,3,3-tetraethylurea, 1,1,3,3-tetrabutylurea, 1,3-dimethoxy-1,3-dimethylurea, 1,3-dimethyl-2-imidazolidinone, and 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone. (Thiocarbamide derivatives) Thiourea derivatives are compounds in which at least one of the four hydrogen atoms of a thiourea molecule is substituted with a substituent. In this case, there are no particular restrictions on the substituent, but it is preferred to be a substituent formed by a carbon atom, a hydrogen atom, and an oxygen atom. Specific examples of thiourea derivatives include N-methylthiourea, ethylthiourea, propylthiourea, isopropylthiourea, 1-butylthiourea, cyclohexylthiourea, N-acetylatedthiourea, N-allylthiourea, (2-methoxyethyl)thiourea, N-phenylthiourea, (4-methoxyphenyl)thiourea, N-(2-methoxyphenyl)thiourea, N-(1-naphthyl)thiourea, (2-pyridyl)thiourea, o-tolylthiourea, and p-tolylthiourea. Examples of 2-substituted thioureas include 1,1-dimethylthiourea, 1,3-dimethylthiourea, 1,1-diethylthiourea, 1,3-diethylthiourea, 1,3-dibutylthiourea, 1,3-diisopropylthiourea, 1,3-dicyclohexylthiourea, N,N-diphenylthiourea, N,N'-diphenylthiourea, 1,3-di(o-tolyl)thiourea, 1,3-di(p-tolyl)thiourea, 1-benzyl-3-phenylthiourea, 1-methyl-3-phenylthiourea, N-allyl-N'-(2-hydroxyethyl)thiourea, and ethylenethiourea. Examples of 3-substituted thioureas include trimethylthiourea, and examples of 4-substituted thioureas include tetramethylthiourea and 1,1,3,3-tetraethylthiourea. From the perspective of suppressing the decrease in transmittance and the decrease in polarization under high-temperature conditions (suppressing orthogonal light leakage), urea compounds are preferably urea derivatives or thiourea derivatives, and more preferably urea derivatives. Among urea derivatives, 1-substituted urea or 2-substituted urea are preferred, and 1-substituted urea is even more preferred. 2-substituted urea include 1,1-substituted urea and 1,3-substituted urea, with 1,3-substituted urea being more preferred. (Moisture content) The moisture content of the polarizing element can be, for example, above the equilibrium moisture content of 40% relative humidity at 20°C and below the equilibrium moisture content of 60% relative humidity at 20°C. Preferably, the moisture content of the polarizing element is below the equilibrium moisture content of 55% relative humidity at 20°C and above the equilibrium moisture content of 45% relative humidity at 20°C. When the moisture content of the polarizing element is above the equilibrium moisture content of 40% relative humidity at 20°C, the operability of the polarizing element increases and it is less prone to breakage. When the moisture content of the polarizing element is below the equilibrium moisture content of 60% relative humidity at 20°C, the transmittance of the polarizing element is less likely to decrease. It is speculated that this is because a higher moisture content in the polarizing element facilitates the polyolefination of PVA-based resins. The moisture content of the polarizing element is the moisture content of the polarizing element in the polarizing plate. As a method to confirm that the moisture content of a polarizing element is within the range of equilibrium moisture content at 20°C and 40% relative humidity or below, one can include storing the polarizing element in an environment adjusted to the aforementioned temperature and relative humidity range, and considering it to have reached equilibrium with the environment if there is no change in quality over a fixed period of time; or calculating the equilibrium moisture content of the polarizing element in an environment adjusted to the aforementioned temperature and relative humidity range in advance, and comparing the moisture content of the polarizing element with the pre-calculated equilibrium moisture content to confirm it. There are no particular limitations on the manufacturing method of polarizing elements with a moisture content of 20°C and 40% or higher and a moisture content of 60% or lower. For example, the polarizing element can be stored in an environment with the above temperature and relative humidity for 10 minutes to 3 hours, or it can be heated at 30°C to 90°C. Other preferred methods for manufacturing polarizing elements with the aforementioned moisture content include storing a laminate containing at least a single-area protective film of the polarizing element or a polarizing plate composed of the polarizing element in an environment adjusted to the aforementioned temperature and relative humidity range for 10 minutes to 120 hours, or heating it at 30°C to 90°C. When manufacturing an image display device employing interlayer filling, the polarizing plate can be assembled into the image display device, and the image display device with the assembled polarizing plate can be stored in an environment adjusted to the aforementioned temperature and relative humidity range for 10 minutes to 3 hours, or heated at 30°C to 90°C before being bonded to the front panel. The optimal moisture content of the polarizing element is achieved by adjusting the moisture content of the polarizing element, either alone or in a laminate containing both a polarizing element and a protective film, to a value within the aforementioned range during the material stage used to construct the polarizing plate. Adjusting the moisture content after the polarizing plate is constructed can lead to excessive curling, which can cause defects when bonded to the image display unit. By adjusting the polarizing element to the aforementioned moisture content during the material stage before constructing the polarizing plate, and then using this polarizing element to construct the polarizing plate, it is easy to construct a polarizing plate with a polarizing element whose moisture content meets the aforementioned value range. Alternatively, the moisture content of the polarizing element in the polarizing plate can be adjusted to a value within the aforementioned range while the polarizing plate is bonded to the image display unit. In this case, the polarizing plate is less prone to curling when bonded to the image display unit. The moisture content of the polarizing plate can be, for example, above the equilibrium moisture content of 40% at 20°C and below the equilibrium moisture content of 60% at 20°C. Preferably, the moisture content of the polarizing plate is below the equilibrium moisture content of 55% at 20°C and above the equilibrium moisture content of 45% at 20°C. A moisture content above the equilibrium moisture content of 40% at 20°C improves the workability of the polarizing plate and makes it less prone to breakage. A moisture content below the equilibrium moisture content of 60% at 20°C makes it less likely for the transmittance of the polarizing plate to decrease. This is presumably because a higher moisture content in the polarizing plate facilitates the polyolefination of PVA-based resins. The method for confirming that the moisture content of the polarizing plate is within the range of equilibrium moisture content at 20°C and 40% relative humidity and below 60% relative humidity is as follows: One method is to store the polarizing plate in an environment adjusted to the aforementioned temperature and relative humidity range, and consider it to have reached equilibrium with the environment if there is no change in mass over a fixed period of time; another method is to pre-calculate the equilibrium moisture content of the polarizing plate in an environment adjusted to the aforementioned temperature and relative humidity range, and compare the moisture content of the polarizing plate with the pre-calculated equilibrium moisture content to confirm its accuracy. There are no particular limitations on the manufacturing method of a polarizing plate with a moisture content of 20°C and 40% or higher and a moisture content of 60% or lower. For example, the polarizing plate can be stored in an environment with the above temperature and relative humidity for 10 minutes to 3 hours, or it can be heated at 30°C to 90°C. When manufacturing an image display device using interlayer filling, a polarizing plate can be assembled onto the image display device, and the image display device with the polarizing plate assembled can be kept in an environment adjusted to the above-mentioned temperature and relative humidity range for 10 minutes to 3 hours, or heated to 30°C to 90°C before being attached to the front panel. Polarizing elements may contain potassium ions and metal ions other than potassium ions. The content of metal ions other than potassium ions in the polarizing element is preferably 0.05% by mass to 10.0% by mass, more preferably 0.05% by mass to 8.0% by mass, and even more preferably 0.1% by mass to 6.0% by mass. When the metal ion content of the polarizing element is 10.0% by mass or less, the polarization degree is less likely to decrease in high temperature and high humidity environments. Furthermore, a metal ion content of 0.05% by mass or higher readily improves durability in high-temperature environments. The metal ion content in the polarizing element can be calculated, for example, by high-frequency inductively coupled plasma (ICP) emission spectroscopy, as the mass fraction (mass%) of the metal element relative to the mass of the polarizing element. It is assumed that the metal element exists in the polarizing element as metal ions, or as metal ions forming a cross-linked structure with polyvinyl alcohol resin components; however, the metal ion content mentioned here is a value based on the number of metal atoms. If the metal ion is not potassium ion, there is no particular limitation, but it is preferably a metal ion other than an alkali metal. Especially from the point of view of color adjustment or imparting durability, it is preferably a metal ion containing at least one transition metal such as cobalt, nickel, zinc, chromium, aluminum, copper, manganese, or iron. Among these metal ions, zinc ion is preferred from the point of view of color adjustment or imparting heat resistance. In polarizing elements, the boron content is preferably 4.0% by mass to 8.0% by mass, more preferably 4.2% by mass to 7.0% by mass, and even more preferably 4.4% by mass to 6.0% by mass. When the boron content of the polarizing element is 8.0% by mass or less, the shrinkage force of the polarizing element can be reduced, and when assembled into an image display device, defects such as peeling are less likely to occur between the polarizing element and other components such as the front panel. Furthermore, from the viewpoint of easily achieving the desired optical characteristics, the boron content is preferably 2.4% by mass or more. The boron content in the polarizing element can be calculated, for example, by ICP emission spectroscopy as the mass fraction (mass%) of boron relative to the mass of the polarizing element. It is assumed that boron exists in the polarizing element in a state of boric acid, or in a cross-linked structure formed by boric acid and polyvinyl alcohol resin, but the boron content mentioned here refers to the value of boron atoms (B). The boron content of the polarizing element is within the aforementioned range, thereby further suppressing the decrease in transmittance even when the component of the image display device, which is constructed as an interlayer filler, is exposed to a high-temperature environment. It is presumed that this is because if the boron content is within the aforementioned range, polyolefin formation is less likely to occur even at high temperatures, thus suppressing the decrease in transmittance. (Manufacturing method of polarizing element) There is no particular limitation on the manufacturing method of polarizing elements. Typical methods include a manufacturing method that involves conveying a pre-wound PVA-based resin film and performing stretching, dyeing, cross-linking, etc. (hereinafter referred to as "manufacturing method 1"); or a method that includes the steps of coating a substrate film with a coating liquid containing PVA-based resin to form a PVA-based resin layer belonging to the coating layer and stretching the resulting laminate (hereinafter referred to as "manufacturing method 2"). Manufacturing method 1 can be manufactured by the following steps: uniaxial stretching of a PVA-based resin film, dyeing the PVA-based resin film with dichroic pigments such as iodine and adsorbing the dichroic pigments, treating the PVA-based resin film with adsorbed dichroic pigments with a boric acid aqueous solution, and washing with water after treatment with boric acid aqueous solution. The swelling step involves immersing the PVA-based resin film in a swelling bath. This step removes dirt and adhesives from the surface of the PVA-based resin film and inhibits uneven dyeing by swelling the film. The swelling bath typically uses a water-based medium, such as water, distilled water, or pure water. Surfactants and alcohols can be added to the swelling bath as needed. From the perspective of controlling the potassium content of the polarizing element, potassium iodide can be used in the swelling bath. Preferably, the concentration of potassium iodide in the swelling bath is 1.5% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.5% by mass or less. The optimal temperature for the swelling bath is between 10°C and 60°C, more preferably between 15°C and 45°C, and even more preferably between 18°C ​​and 30°C. The degree of swelling of the PVA resin film is affected by the swelling bath temperature; therefore, the immersion time in the swelling bath cannot be fixed. The optimal time is between 5 seconds and 300 seconds, more preferably between 10 seconds and 200 seconds, and even more preferably between 20 seconds and 100 seconds. The swelling step can be performed only once or multiple times as needed. The dyeing step involves immersing a PVA-based resin film in a dyeing bath (iodine solution), which allows for the adsorption and alignment of dichroic pigments such as iodine onto the PVA-based resin film. The iodine solution is preferably an aqueous iodine solution containing iodine and an iodide as a co-solvent. Examples of iodides include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, and titanium iodide. From the viewpoint of controlling the potassium content in the polarizing element, potassium iodide is preferred. The iodine concentration in the staining bath is preferably 0.01% by mass to 1% by mass, more preferably 0.02% by mass to 0.5% by mass. The iodide concentration in the staining bath is preferably 0.01% by mass to 10% by mass, more preferably 0.05% by mass to 5% by mass, and even more preferably 0.1% by mass to 3% by mass. The optimal temperature for the dyeing bath is between 10°C and 50°C, more preferably between 15°C and 45°C, and even more preferably between 18°C ​​and 30°C. The degree of dyeing of the PVA resin film is affected by the dyeing bath temperature; therefore, the immersion time in the dyeing bath cannot be fixed. It is preferably between 10 seconds and 300 seconds, and more preferably between 20 seconds and 240 seconds. The dyeing step can be performed only once or multiple times as needed. The crosslinking step involves immersing the dyed PVA-based resin film in a treatment bath (crosslinking bath) containing boron compounds. The boron compounds crosslink the polyvinyl alcohol-based resin film, and iodine or dye molecules are adsorbed onto this crosslinked structure. Examples of boron compounds include boric acid, borates, and borax. The crosslinking bath is generally an aqueous solution, but it can also be a mixture of an organic solvent and water that is miscible with water. From the perspective of controlling the potassium content in the polarizing element, the crosslinking bath preferably contains potassium iodide. In the crosslinking bath, the concentration of boron compound is preferably 1% to 15% by mass, more preferably 1.5% to 10% by mass, and even more preferably 2% to 5% by mass. When potassium iodide is used in the crosslinking bath, the concentration of potassium iodide in the crosslinking bath is preferably 1% to 15% by mass, more preferably 1.5% to 10% by mass, and even more preferably 2% to 5% by mass. The temperature of the crosslinking bath is preferably between 20°C and 70°C, and more preferably between 30°C and 60°C. The degree of crosslinking of PVA resin films is affected by the temperature of the crosslinking bath, so the immersion time in the crosslinking bath cannot be fixed. It is preferably between 5 seconds and 300 seconds, and more preferably between 10 seconds and 200 seconds. The crosslinking step can be performed only once, or multiple times as needed. The stretching step is a process of stretching a PVA-based resin film by a specific ratio in at least one direction. Generally, it involves uniaxially stretching the PVA-based resin film in the transport direction (longitudinal direction). There are no particular limitations on the stretching method; either wet stretching or dry stretching can be used. The stretching step can be performed only once or multiple times as needed. The stretching step can be performed at any stage of the manufacturing of the polarizing element. In the wet stretching method, the treatment bath (stretching bath) can typically be water, or a mixture of water and an organic solvent that is miscible with water. From the viewpoint of controlling the potassium content in the polarizing element, the stretching bath preferably contains potassium iodide. When potassium iodide is used in the stretching bath, the concentration of potassium iodide in the stretching bath is preferably 1% to 15% by mass, more preferably 2% to 10% by mass, and even more preferably 3% to 6% by mass. From the viewpoint of suppressing film rupture during stretching, the treatment bath (stretching bath) may contain boron compounds. When boron compounds are contained, the concentration of boron compounds in the stretching bath is preferably 1% to 15% by mass, more preferably 1.5% to 10% by mass, and even more preferably 2% to 5% by mass. The temperature of the stretching bath is preferably between 25°C and 80°C, more preferably between 40°C and 75°C, and even more preferably between 50°C and 70°C. The degree of stretching of the PVA resin film is affected by the temperature of the stretching bath, so the immersion time in the stretching bath cannot be fixed. It is preferably between 10 seconds and 800 seconds, and more preferably between 30 seconds and 500 seconds. The stretching treatment in the wet stretching method can be carried out together with any one or more of the following treatment steps: swelling step, dyeing step, crosslinking step, and washing step. Examples of dry stretching methods include inter-roll stretching, heated roll stretching, and compression stretching. Furthermore, dry stretching can be performed concurrently with the drying step. The total elongation ratio (cumulative elongation ratio) of the polyvinyl alcohol resin film can be appropriately set according to the purpose, preferably more than 2 times and less than 7 times, more preferably more than 3 times and less than 6.8 times, and even more preferably more than 3.5 times and less than 6.5 times. The cleaning step involves immersing the polyvinyl alcohol (PVA) resin film in a cleaning bath to remove foreign matter remaining on the surface of the PVA resin film. The cleaning bath typically uses a water-based medium, such as water, distilled water, or pure water. Furthermore, from the perspective of controlling the potassium content in the polarizing element, potassium iodide is preferably used in the cleaning bath. In this case, the concentration of potassium iodide in the cleaning bath is preferably 1% by mass to 10% by mass, more preferably 1.5% by mass to 4% by mass, and even more preferably 1.8% by mass to 3.8% by mass. The ideal temperature for the washing bath is between 5°C and 50°C, more preferably between 10°C and 40°C, and even more preferably between 15°C and 30°C. The cleanliness of the PVA resin membrane is affected by the washing bath temperature; therefore, the immersion time cannot be fixed. Ideally, it should be between 1 second and 100 seconds, more preferably between 2 seconds and 50 seconds, and even more preferably between 3 seconds and 20 seconds. The washing step can be performed only once or multiple times as needed. The drying step involves drying the PVA-based resin film, which has been washed in the cleaning step, to obtain a polarizing element. Drying can be carried out by any suitable method, such as natural drying, air drying, or heat drying. Manufacturing method 2 can be performed by the following steps: coating a substrate film with a coating solution containing a PVA-based resin; uniaxially stretching the resulting laminated film; dyeing the PVA-based resin layer of the uniaxially stretched laminated film with a dichroic dye to adsorb and form a polarizing element; treating the film adsorbed with a boric acid aqueous solution; and washing with water after the boric acid aqueous solution treatment. The substrate film used to form the polarizing element can be used as a protective layer for the polarizing element. The substrate film can be peeled off from the polarizing element as needed. <Transparent Protective Film> The transparent protective film (hereinafter also referred to as "protective film") used in this embodiment is adhered to at least one side of the polarizing element through an adhesive layer. The transparent protective film may be adhered to one side of the polarizing element, but it is preferred to adhere to both sides. The protective film can also possess other optical functions and can be formed into a multilayered structure. From an optical point of view, the protective film thickness is preferably thin, but if it is too thin, the strength will decrease and the processability will be poor. The appropriate film thickness is 5 μm to 100 μm, preferably 10 μm to 80 μm, and even more preferably 15 μm to 70 μm. The protective film can be made of cellulose ester, polycarbonate resin, cyclic olefin resin such as norbornene, (meth)acrylic acid polymer, or polyethylene terephthalate polyester resin. When the protective film is laminated to both sides of the polarizing element using a water-based adhesive such as PVA adhesive, from the viewpoint of moisture permeability, the protective film on at least one side is preferably either a cellulose ester or a (meth)acrylic acid polymer film, with a cellulose ester film being more preferred. At least one protective film can provide phase difference functionality for purposes such as viewing angle compensation. In this case, the protective film itself can have phase difference functionality, can have a separate phase difference layer, or can be a combination of both. The film with phase difference functionality can be directly bonded to the polarizing element through an adhesive, or it can be constructed by bonding it to the polarizing element through another protective film bonded to the polarizing element through an adhesive or bonding agent. <First Adhesive Layer> The first adhesive constituting the first adhesive layer for bonding the protective film to the polarizing element is an adhesive containing a urea-based compound. The adhesive can be a water-based adhesive, a solvent-based adhesive, or an active energy line curing adhesive, but a water-based adhesive is preferred, and more preferably, it contains a PVA-based resin. By using an adhesive containing a urea-based compound, the decrease in transmittance of the polarizing plate under high-temperature environments can be suppressed. The thickness of the adhesive coating can be set to any value, for example, by obtaining an adhesive layer of the desired thickness after curing or heating (drying). The thickness of the adhesive layer is preferably 0.01 μm to 7 μm, more preferably 0.01 μm to 5 μm, even more preferably 0.01 μm to 2 μm, and most preferably 0.01 μm to 1 μm. The following description of the adhesive describes a preferred range when the polarizing element does not contain urea compounds during manufacturing. When the polarizing element contains urea compounds, the following values ​​can be adjusted appropriately. Specific examples of urea compounds can be directly applied to the examples of urea compounds contained in the polarizing element described above. During the bonding of the polarizing element and the protective film, a portion of the urea compound may migrate from the adhesive layer to the polarizing element during the drying process of forming the adhesive layer. When the adhesive contains a water-based adhesive of PVA-based resin, the content of urea compounds is preferably 0.1 parts by weight to 400 parts by weight, more preferably 1 part by weight to 200 parts by weight, and even more preferably 3 parts by weight to 100 parts by weight, relative to 100 parts by weight of PVA-based resin. When the content is less than 0.1 parts by weight, the polyolefin suppression effect of the polarizing element under high-temperature conditions is insufficient. On the other hand, when the content exceeds 400 parts by weight, urea will precipitate after the polarizing plate is manufactured, resulting in increased haze. The adhesive may further contain dicarboxylic acids. Examples of dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, tartaric acid, glutamic acid, malic acid, maleic acid, fumaric acid, itaconic acid, mucoacic acid, 1,4-cyclohexanedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 4,4-biphenyldicarboxylic acid, 2,5-pyridinedicarboxylic acid, 3,5-pyridinedicarboxylic acid, diphenyl tannic acid, diphenylmethanedicarboxylic acid, oxaloacetic acid, methyl fumaric acid, and 2,6-pyridinedicarboxylic acid. Citric acid, malic acid, maleic acid, or tartaric acid are preferred among these. These dicarboxylic acids may be used alone or in combination of two or more. When the adhesive contains a water-based adhesive of PVA-based resin, the dicarboxylic acid content is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 10 parts by weight, and even more preferably 0.1 to 5 parts by weight, or even less than 1 part by weight, relative to 100 parts by weight of PVA-based resin. A content of 0.01 parts by weight or more further improves the polyolefin suppression effect of the polarizing element under high-temperature conditions. On the other hand, a content of 50 parts by weight or less easily prevents the precipitation of dicarboxylic acid after the polarizing plate is manufactured. In a configuration where a transparent protective film is bonded to both sides of a polarizing element via an adhesive layer, the adhesive layer used to bond the transparent protective film to the side opposite to the first adhesive layer can be formed of an adhesive that does not contain urea compounds, but it is more preferably formed of an adhesive that contains urea compounds. The adhesive layer used to bond the transparent protective film to the side opposite to the first adhesive layer can be formed of an adhesive with the same composition as the first adhesive, or it can be formed of an adhesive with a different composition than the first adhesive. When the polarizing element is not treated to contain urea compounds, only one side of the adhesive layer on both sides of the polarizing element may contain urea compounds, but it is more preferably that both sides contain urea compounds. To meet the demand for thinner polarizing plates, a polarizing plate with a transparent protective film on only one side of the polarizing element was developed. As a method for manufacturing this polarizing plate with a transparent protective film on only one side of the polarizing element, firstly, a polarizing plate with a transparent protective film bonded to both sides through an adhesive layer is manufactured, and then the transparent protective film on one side is peeled off. (Water-based adhesive) Any suitable water-based adhesive can be used, but it is preferred to use a water-based adhesive containing PVA-based resin (PVA-based adhesive). From the viewpoint of adhesion, the average degree of polymerization of the PVA-based resin contained in the water-based adhesive is preferably 100 to 5500, more preferably 1000 to 4500. From the viewpoint of adhesion, the average degree of saponification is preferably 85 mol% to 100 mol%, more preferably 90 mol% to 100 mol%. The PVA-based resin contained in the water-based adhesive preferably contains acetyl acetyl groups because PVA-based resin layers exhibit excellent adhesion and durability to the protective film. PVA-based resins containing acetyl acetyl groups can be obtained, for example, by reacting PVA-based resins and diacetone olefins by any method. The degree of acetyl acetyl modification in PVA-based resins containing acetyl acetyl groups is typically 0.1 mol% or more, preferably 0.1 mol% or more and 20 mol% or less. The resin concentration of the water-based adhesive is preferably 0.1% by mass or more and 15% by mass, more preferably 0.5% by mass or more and 10% by mass. Water-based adhesives may also contain crosslinking agents. Known crosslinking agents can be used. Examples of crosslinking agents include water-soluble epoxy compounds, dialdehydes, and isocyanates. When the PVA-based resin is a PVA-based resin containing acetyl groups, the crosslinking agent is preferably any one of glyoxal, glyoxylate, or hydroxymethyl melamine, more preferably any one of glyoxal or glyoxylate, and most preferably glyoxal. When the adhesive is a water-based adhesive containing PVA-based resin, the crosslinking agent content is preferably 1 part to 60 parts by weight, more preferably 1.5 parts to 50 parts by weight, and even more preferably 2 parts to 45 parts by weight, relative to 100 parts by weight of PVA-based resin. A content of 1 part or more improves water resistance. On the other hand, a content of 60 parts by weight or less helps maintain the stability of the adhesive solution. Aqueous adhesives may also contain organic solvents. Alcohols are preferred in terms of their miscibility with water, with methanol or ethanol being more preferred. The methanol concentration in the aqueous adhesive is preferably 10% by mass to 70% by mass, more preferably 15% by mass to 60% by mass, and even more preferably 20% by mass to 60% by mass. Maintaining a methanol concentration of 10% by mass or higher makes it easier to suppress the polyolefin formation of PVA resins at high temperatures. Furthermore, maintaining a methanol content of 70% by mass or less helps to suppress color deterioration. Some urea derivatives have low solubility in water but high solubility in alcohols. In this case, as a preferred approach, the urea compound can be dissolved in an alcohol to prepare an alcohol solution of the urea compound, which is then added to the PVA aqueous solution to prepare the adhesive. <Phase difference layer> The retardation layer can be one layer or two or more layers. The retardation layer may include a substrate film supporting the retardation layer, an adhesive layer for bonding multiple retardation layers, etc. The retardation layer may further include an alignment film. Preferably, the retardation layer has at least one selected from the group consisting of a quarter-wave plate, a half-wave plate, a positive C-plate, and a positive A-plate. When the retardation layer has a half-wave plate, the half-wave plate layer and the quarter-wave plate layer can be sequentially stacked from the polarizing element side. When the retardation layer has a positive C-plate, the quarter-wave plate or the positive A-plate and the positive C-plate can be sequentially stacked from the polarizing element side, or the positive C-plate and the quarter-wave plate or the positive A-plate can be sequentially stacked from the polarizing element side. From the viewpoint of improving the contrast in the oblique direction of liquid crystal display devices such as IPS mode, the retardation layer preferably has a positive A-plate and a positive C-plate. The thickness of the phase retardation layer is, for example, 0.1 μm to 10 μm, preferably 0.5 μm to 8 μm, and even more preferably 1 μm to 6 μm. The retardation layer has a cured layer of a polymeric liquid crystal compound. A composition containing a polymeric liquid crystal compound can be coated onto a substrate film and cured to form the retardation layer. An alignment film can be formed between the substrate film and the coated layer. The retardation layer can be assembled onto a polarizing plate in the form of an alignment film and a substrate film. Preferably, the surface of the retardation layer facing the polarizer is a cured layer containing a polymeric liquid crystal compound. The surface of the retardation layer facing the polarizing element can be the surface of a layer exhibiting the phase retardation, or it can be an alignment film. The retardation layer may have two or more hardened layers of polymeric liquid crystal compounds, preferably with the two hardened layers of polymeric liquid crystal compounds in direct contact. The retardation layer is preferably in direct contact between the positive A plate and the positive C plate. The direct contact of the two hardened layers of polymeric liquid crystal compounds also includes the contact of the two hardened layers of polymeric liquid crystal compounds separated by an alignment film. Examples of substrate films include cyclic polyolefin resin films; cellulose acetate resin films containing resins such as cellulose triacetate and cellulose diacetate; polyester resin films containing resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polycarbonate resin films; (meth)acrylic resin films; and polypropylene resin films, as well as other well-known thermoplastic resin films in this field. From the perspective of thinness, the thickness of the substrate film is typically 100 μm or less, preferably 80 μm or less, more preferably 60 μm or less, even more preferably 40 μm or less, even more preferably 30 μm or less, and typically 5 μm or more, preferably 10 μm or more. A hard coating can be formed on a thermoplastic resin film. The hard coating can be formed on one side or both sides of the thermoplastic resin film. By applying a hard coating, a thermoplastic resin film with improved hardness and scratch resistance can be formed. In addition to the layer containing a cured polymeric liquid crystal compound, the phase retardation layer may also contain a layer formed of a resin film. The resin film may be the aforementioned thermoplastic resin film. The liquid crystal layer exhibiting phase difference can be formed using known liquid crystal compounds. There is no particular limitation on the type of liquid crystal compound contained in the composition containing the polymerizable liquid crystal compound; rod-shaped liquid crystal compounds, disk-shaped liquid crystal compounds, and mixtures thereof can be used. The composition containing the polymerizable liquid crystal compound may contain a high-molecular-weight liquid crystal compound. Examples of liquid crystal compounds include those described in Japanese Patent Application Publication No. 11-513019, Japanese Patent Application Publication No. 2005-289980, Japanese Patent Application Publication No. 2007-108732, Japanese Patent Application Publication No. 2010-244038, Japanese Patent Application Publication No. 2010-31223, Japanese Patent Application Publication No. 2010-270108, Japanese Patent Application Publication No. 2011-6360, Japanese Patent Application Publication No. 2011-207765, Japanese Patent Application Publication No. 2016-81035, International Publication No. 2017 / 043438, and Japanese Patent Application Publication No. 2011-207765. In addition to the liquid crystal compound, compositions containing polymerizable liquid crystal compounds may contain polymerization initiators, polymerizable monomers, surfactants, solvents, adhesion modifiers, plasticizers, and alignment agents. Common methods for coating compositions containing polymerizable liquid crystal compounds include mold coating. Common methods for curing compositions containing polymerizable liquid crystal compounds include irradiation with active energy rays (e.g., ultraviolet light). A polarizing plate is configured such that the absorption axis of the polarizing element and the slow axis of the retardation layer form a specific angle. This polarizing plate has anti-reflection properties and can function as a circular polarizing plate. When the retardation layer has a quarter-wavelength plate, the angle between the absorption axis of the polarizing element and the slow axis of the quarter-wavelength plate can be 45°±10°. The retardation layer can have positive wavelength dispersion or negative wavelength dispersion. The quarter-wavelength plate preferably has negative wavelength dispersion. The alignment control force of the alignment film is to align the polymeric liquid crystal compound contained in the liquid crystal layer exhibiting a phase difference formed on the alignment film in the desired direction. Examples of alignment films include alignment polymer films formed of alignment polymers, photoalignment polymer films formed of photoalignment polymers, and groove alignment films having an embossed pattern or a plurality of grooves on the film surface. The thickness of the alignment film is typically 0.01 μm to 10 μm, preferably 0.01 μm to 5 μm. Orientation polymer films are formed by coating a substrate film with a composition obtained by dissolving an orientation polymer in a solvent, removing the solvent, and then subjecting the film to friction treatment as needed. The orientation control force can be arbitrarily adjusted by the surface condition of the orientation polymer or the friction conditions. The alignment control force is formed by coating a composition containing a polymer or monomer with photoreactive groups and a solvent onto a substrate film and irradiating it with polarized light. In this case, the alignment control force can be arbitrarily adjusted by the polarization irradiation conditions of the photoalignable polymer. The groove alignment film can be formed, for example, by the following methods: exposing and developing an exposure mask with a patterned slit on the surface of a photosensitive polyimide film, thereby forming a raised pattern; forming an uncured film of an active energy line curable resin on a plate-shaped base plate with grooves on its surface, and transferring the film to a substrate film and curing it; forming an uncured layer of active energy line curable resin on a substrate film, and pressing a roller-shaped base plate with raised and recessed grooves onto the layer, thereby forming a raised and recessed pattern and curing it, etc. <Second Adhesive Layer> The second adhesive layer used to bond the transparent protective film and the phase retardation layer is formed by an active energy line curing type second adhesive. Active energy line curing type adhesives are adhesives that are cured by irradiation with active energy lines. The active energy beam can be ultraviolet light, visible light, electron beam, X-ray, etc. Any suitable irradiation condition can be used as long as it allows the active energy beam curing adhesive to harden. For example, the accelerating voltage for electron beam irradiation is preferably 5kV to 300kV, more preferably 10kV to 250kV. In ultraviolet curing types, the light irradiation intensity for the active energy beam curing adhesive can be, for example, 10 to 1000 mJ / cm². 2 The irradiation intensity is preferably in the wavelength range below 400 nm. This irradiation intensity can be achieved through single or multiple irradiations, with the cumulative light intensity preferably being 10 mJ / cm². 2 The above setting is preferably between 100 and 1000 mJ / cm. 2 . There are no particular limitations on the light source used for the polymerization and curing of adhesives. Examples include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, halogen lamps, carbon arc lamps, tungsten lamps, gallium lamps, excimer lasers, LED light sources with an emission wavelength range of 380 to 440 nm, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps. From the viewpoint of energy stability or ease of use, ultraviolet light sources with emission distribution below 400 nm are preferred. When using active energy line curing components, heat treatment can be performed simultaneously with active energy line irradiation or after active energy line irradiation. Before forming the adhesive coating layer, one or both sides of the bonding surface can be subjected to easy bonding treatments such as saponification, corona discharge, plasma treatment, flame treatment, primer treatment, and anchor coating. Examples of active energy line-curing adhesives include cationic polymeric active energy line-curing adhesives containing cationic polymeric compounds and cationic polymerization initiators; free radical polymeric active energy line-curing adhesives containing free radical polymeric compounds and free radical polymerization initiators; active energy line-curing adhesives containing both cationic polymeric compounds and free radical polymeric compounds, and further containing both cationic polymerization initiators and free radical polymerization initiators; and electron beam curing adhesives that do not contain an initiator and are cured by irradiation with an electron beam. From the viewpoint of suppressing orthogonal light leakage from polarizing plates, the second adhesive is preferably one containing a cationic polymeric compound. Cationic polymerizable compounds include epoxy compounds having one or more epoxy groups within their molecules, cyclobutane compounds having one or more cyclobutane rings within their molecules, and vinyl compounds having cationic polymerizable groups. The second adhesive may contain one or more cationic polymerizable compounds. Relative to 100 parts by mass of the total cationic polymeric composition, the cationic polymeric compound content in the second adhesive is preferably 80 parts by mass to 100 parts by mass, more preferably 90 parts by mass to 99.5 parts by mass, and even more preferably 95 parts by mass to 99 parts by mass. Examples of epoxy compounds include alicyclic epoxy compounds, aromatic epoxy compounds, hydrogenated epoxy compounds, and aliphatic epoxy compounds. From the viewpoint of weather resistance, curing speed, and adhesion, epoxy compounds preferably contain at least one type selected from the group consisting of alicyclic epoxy compounds and aliphatic epoxy compounds, and more preferably contain alicyclic epoxy compounds. Alicyclic epoxy compounds are compounds having one or more epoxy groups bonded to an alicyclic ring within the molecule, preferably having two or more epoxy groups bonded to an alicyclic ring within the molecule. "Epoxy groups bonded to an alicyclic ring" refers to the cross-linked oxygen atom -O- in the structure shown in formula (I) below. In formula (I) below, m is an integer from 2 to 5. Remove (CH) from equation (I) above 2) m Compounds in which one or more hydrogen atoms are bonded to other chemical structures can be alicyclic epoxides. (CH 2) m One or more hydrogen atoms may be suitably replaced by a straight-chain alkyl group such as methyl or ethyl. From the perspective of increasing the glass transition temperature of the hardened material, it is preferable to be an alicyclic epoxy compound having an epoxy cyclopentane structure (m=3 in the above formula (I)) or an epoxy cyclohexane structure (m=4 in the above formula (I)). Alicyclic epoxides can be exemplified by compounds A through M listed below. Furthermore, the chemical formulas A through M shown in the following paragraphs correspond to compounds A through M, respectively. A: 3,4-Epoxycyclohexanecarboxylic acid 3,4-epoxycyclohexylmethyl ester; B: 3,4-Epoxy-6-methylcyclohexanecarboxylic acid 3,4-Epoxy-6-methylcyclohexylmethyl ester; C: Ethyl bis(3,4-epoxycyclohexane carboxylate); D: Bis(3,4-epoxycyclohexylmethyl) adipate; E: Bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate; F: Diethylene glycol bis(3,4-epoxycyclohexylmethyl ether); G: Ethylene glycol bis(3,4-epoxycyclohexylmethyl ether); H: 2,3,14,15-diepoxy-7,11,18,21-tetraoxatrispiro[5.2.2.5.2.2]cosicosane; I: 3-(3,4-epoxycyclohexyl)-8,9-epoxy-1,5-dioxaspiro[5.5]undecane; J: 4-Vinylcyclohexene dioxide; K: Limonene dioxide; L: Bis(2,3-epoxycyclopentyl) ether; M: Dicyclopentadiene dioxide. A: B: C: D: E: F: G: H: I: J: K: L: M: For ease of acquisition, the preferred alicyclic epoxy compound is 3,4-epoxycyclohexanecarboxylic acid methyl 3,4-epoxycyclohexyl ester. Furthermore, from the viewpoint of high-temperature durability, the preferred compound is the 1,2-epoxy-4-(2-epoxyethylene)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol. Alicyclic epoxy compounds can be used alone or in combination of several different compounds. Compared to the total amount of fully polymerizable compounds in the second adhesive (100 parts by mass), the content of alicyclic epoxy compounds is preferably 1 part by mass to 80 parts by mass, more preferably 3 parts by mass to 70 parts by mass, and even more preferably 3 parts by mass to 60 parts by mass. When the content of alicyclic epoxy compounds is within this range, curing by irradiation with active energy lines such as ultraviolet light can proceed rapidly, forming a cured layer with excellent heat resistance and resistance to damp heat. Aliphatic epoxy compounds are compounds having at least one epoxy ring bonded to an aliphatic carbon atom within their molecule, preferably having two or more epoxy rings within their molecule. Examples of aliphatic epoxy compounds include monofunctional epoxy compounds such as butyl glycidyl ether and 2-ethylhexyl glycidyl ether; difunctional epoxy compounds such as 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and neopentyl glycol diglycidyl ether; trifunctional or higher epoxy compounds such as trimethylolpropane triglycidyl ether and neopentyltetraglycidyl ether; and epoxy compounds such as 4-vinylcyclohexene dioxide and limonene dioxide, which have one epoxy group directly bonded to an alicyclic ring and an ethylene oxide ring bonded to an aliphatic carbon atom. From the viewpoint of obtaining a second adhesive with low viscosity and easy coating, it is preferable to be a difunctional epoxy compound (also known as an "aliphatic diester") having two ethylene oxide rings bonded to aliphatic carbon atoms in the molecule, as shown in the following formula (II). In the above formula (II), Y is an alkyl group with 2 to 9 carbon atoms, an alkyl group with 4 to 9 carbon atoms having an ether bond in the middle, or a divalent hydrocarbon group with 6 to 18 carbon atoms having an alicyclic structure. Specific examples of compounds represented by formula (II) include diglycidyl ether of alkyl diols; diglycidyl ether of oligoalkyl diols with a repeat of about 4; and diglycidyl ether of alicyclic diols. Examples of diols (diols) that can form aliphatic diepoxides of formula (II) include ethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-2,4-pentanediol, 2,4-pentanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,6- Alkanediols such as hexanediol, 1,7-heptanediol, 3,5-heptanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, and 1,9-nonanediol; oligoalkylene diols such as diethylene glycol, triethylene glycol, tetraethylene glycol, and dipropylene glycol; and alicyclic diols such as cyclohexanediol and cyclohexanediol. From the viewpoint of obtaining a second adhesive with low viscosity and easy application, aliphatic epoxy compounds are preferably those containing 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, or neopentyl glycol diglycidyl ether. From the viewpoint of maintaining optical properties, 1,6-hexanediol diglycidyl ether or neopentyl tetraethanolamine polyglycidyl ether are preferred. Aliphatic epoxy compounds can be used alone or in combination of several different compounds. Relative to the total amount of fully polymerizable compounds in the second adhesive (100 parts by mass), the content of aliphatic epoxy compounds can be, for example, 1 to 90 parts by mass, preferably 1 to 40 parts by mass, more preferably 3 to 30 parts by mass, even more preferably 5 to 20 parts by mass, and most preferably 7 to 15 parts by mass. When the content of aliphatic epoxy compounds is within this range, a second adhesive with low viscosity and easy application can be obtained. Aromatic epoxy compounds are compounds that have an aromatic ring and an epoxy group within their molecules. Specific examples include bisphenol-type epoxy compounds or their oligomers, such as bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, and bisphenol S diglycidyl ether; phenolic varnish-type epoxy resins, such as phenol / phenolic varnish epoxy resin, cresol / phenolic varnish epoxy resin, and hydroxybenzaldehyde phenol / phenolic varnish epoxy resin; multifunctional epoxy compounds, such as 2,2',4,4'-tetrahydroxydiphenylmethane glycidyl ether and 2,2',4,4'-tetrahydroxydiphenyl ketone glycidyl ether; and multifunctional epoxy resins, such as epoxidized polyvinylphenol. From the viewpoint of reducing the viscosity of the second adhesive, the aromatic epoxy compound is preferably one containing at least one of the following groups: glycidyl ether of phenols, glycidyl ether of aromatic compounds having two or more alcoholic hydroxyl groups, glycidyl ether of polyphenols, glycidyl ester of benzoic acid, glycidyl ester of polybasic acid, epoxide of styrene oxide, or epoxide of divinylbenzene. From the viewpoint of improving the curability of the second adhesive, the aromatic epoxy compound is preferably one with an epoxy group equivalent of 80 to 500. Aromatic epoxy compounds can be used alone or in combination of several different aromatic epoxy compounds. Compared to the total amount of fully polymerizable compounds in the second adhesive (100 parts by mass), the content of aromatic epoxy compounds is preferably 1 part by mass to 70 parts by mass, more preferably 5 parts by mass to 60 parts by mass, even more preferably 7 parts by mass to 55 parts by mass, and most preferably 10 parts by mass to 50 parts by mass. When the content of aromatic epoxy compounds is within this range, the hydrophobicity of the hardened layer can be improved, and the diffusion of dichroic pigments to the outside of the polarizer under high temperature and high humidity conditions can be more effectively suppressed. The hydrogenated epoxy compound is an epoxypropyl ether of a polyol having an alicyclic ring. It can be obtained by selectively hydrogenating an aromatic polyol at its aromatic ring under catalyst and pressure, thereby obtaining a nucleus-hydrogenated polyhydroxy compound, and then epoxypropylating the nucleus-hydrogenated polyhydroxy compound. Specific examples of aromatic polyols include bisphenol-type compounds such as bisphenol A, bisphenol F, and bisphenol S; phenolic varnish-type resins such as phenol / phenolic varnish resin, cresol / phenolic varnish resin, and hydroxybenzaldehyde / phenolic varnish resin; and multifunctional compounds such as tetrahydroxydiphenylmethane, tetrahydroxydiphenyl ketone, and polyvinylphenol. Hydrogenation of the aromatic ring of an aromatic polyol yields an alicyclic polyol, which is then reacted with epichlorohydrin to form an epoxypropyl ether. A preferred example of a hydrogenated epoxy compound is the diglycidyl ether of hydrogenated bisphenol A. Oxycyclobutane compounds are compounds having one or more oxocyclobutyl groups (oxocyclobutane rings) within their molecules, and can be aliphatic, alicyclic, or aromatic compounds. Examples of oxocyclobutane compounds having one oxocyclobutyl group include 3-ethyl-3-hydroxymethyloxocyclobutane, 2-ethylhexyloxocyclobutane, 3-ethyl-3-(phenoxymethyl)oxocyclobutane, and 3-(cyclohexyloxy)methyl-3-ethyloxocyclobutane. Examples of oxocyclobutane compounds having two or more oxocyclobutyl groups include 1,4-bis[{(3-ethyloxocyclobutane-3-yl)methoxy}methyl]benzene (also known as "xylyldioxocyclobutane") and bis(3-ethyl-3-oxocyclobutylmethyl) ether. These oxocyclobutane compounds can be used alone or in combination of two or more. Oxycyclobutane compounds can be used as the main component of cationic polymerizable compounds or in combination with epoxide compounds. The cyclobutane compound is preferably a cyclobutane compound containing two or more cyclobutane groups within the molecule. By containing this cyclobutane compound, a dense and highly crosslinked cured material can be obtained, resulting in a polarizing plate that is less prone to changes in optical properties. Vinyl compounds include aliphatic or alicyclic vinyl ether compounds. Vinyl compounds include vinyl ethers of alkyl or enols with 5 to 20 carbon atoms, such as n-pentyl vinyl ether, isopentyl vinyl ether, n-hexyl vinyl ether, n-octyl vinyl ether, 2-ethylhexyl vinyl ether, n-dodecyl vinyl ether, stearyl vinyl ether, and oleyl vinyl ether; vinyl ethers containing hydroxyl groups, such as 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, and 4-hydroxybutyl vinyl ether; vinyl ethers of monools containing aliphatic or aromatic rings, such as cyclohexyl vinyl ether, 2-methylcyclohexyl vinyl ether, cyclohexylmethyl vinyl ether, and benzyl vinyl ether; and monovinyl ethers of glycerol, 1,4-butanediol, and 1,4-butanediol divinyl ether. Mono-to-polyvinyl ethers of polyols such as methyl ether, 1,6-hexanediol divinyl ether, neopentyl glycol divinyl ether, neopentyl tetraethylene glycol divinyl ether, neopentyl tetraethylene glycol tetraethylene ether, trimethylolpropane divinyl ether, trimethylolpropane trivinyl ether, 1,4-dihydroxycyclohexane monovinyl ether, 1,4-dihydroxycyclohexane monovinyl ether, 1,4-dihydroxymethylcyclohexane monovinyl ether, 1,4-dihydroxymethylcyclohexane divinyl ether; polyalkylene glycol mono-to-divinyl ethers such as diethylene glycol divinyl ether, triethylene glycol divinyl ether, diethylene glycol monobutyl monovinyl ether; and other vinyl ethers such as glycidyl ether and ethylene glycol vinyl ether methacrylate. Vinyl compounds can be used as the main component of cationic polymerizable compounds, or in combination with epoxy compounds or epoxy compounds and cyclobutane compounds. By using vinyl compounds in combination, the curing speed can be increased or the viscosity of the adhesive can be reduced. The second adhesive may further contain other curing compounds besides those mentioned above. Specific examples of other curing compounds include lactone compounds, cyclic acetal compounds, cyclic sulfide compounds, spiroacetate compounds, and other cationic polymeric compounds besides those mentioned above. The second adhesive preferably contains a polymerization initiator to initiate polymerization. When the second adhesive contains a cyclobutane compound, an epoxy compound, or the like as a polymerizable compound, a photocationic polymerization initiator is preferably used. Photocationic polymerization initiators are those that can generate cationic species or Lewis acids by irradiation with active energy lines such as visible light, ultraviolet light, X-rays, or electron beams, thus initiating the polymerization reaction of cationic polymerizable compounds. Since photocationic polymerization initiators use light as a catalyst, they exhibit excellent storage stability and workability even when mixed with polymerizable compounds. Examples of compounds that generate cationic species or Lewis acids by irradiation with active energy lines include onium salts of aromatic monazite or aromatic strontium salts, aromatic diazonium salts, and iron / aromatic complexes. Aromatic monoxides are compounds containing a diaryl monoxide cation, typically a diphenyl monoxide cation. Aromatic strontium salts are compounds containing triarylstrontium cations, such as triphenylstrontium cation and 4,4'-bis(diphenylstrontium)diphenyl sulfide cation. Aromatic diazonium salts are compounds containing diazonium cations, such as benzenediazonium cation. Iron / aromatic complexes are typically di(cyclopentadiene)iron(II)aromatic cation complexes. The aforementioned cations and anions (negative ions) pair to form photocationic polymerization initiators. Examples of anions constituting photocationic polymerization initiators include specific phosphorus-based anions [(Rf]]. n PF 6-n ] - hexafluorophosphate anion PF 6 - SbF6 hexafluoroantimonate anion 6 - Pentafluorohydroxyantimonate anion SbF 5(OH) - AsF hexafluoroarsenate anion 6 - Tetrafluoroborate anion BF 4 - Tetra(pentafluorophenyl)borate anion B(C) 6F 5) 4 - From the perspective of the curability of the polymerizable compound and the safety of the resulting cured layer, a special phosphorus-based anion [(Rf)] is preferred as the photocationic polymerization initiator. n PF 6-n ] - hexafluorophosphate anion PF 6 - . Photocationic polymerization initiators can be used alone or in combination of several different types. Among them, aromatic strontium salts have ultraviolet absorption characteristics even in the wavelength range of around 300 nm, thus exhibiting excellent curing properties and forming cured products with good mechanical strength or adhesion strength, making them superior. Relative to 100 parts by mass of the polymerizable compound, the content of the polymerization initiator in the cationic polymerizable composition is typically 0.5 parts by mass to 10 parts by mass, preferably 6 parts by mass or less, and more preferably 3 parts by mass or less. When the content of the polymerization initiator is within this range, the polymerizable compound can be sufficiently hardened, and the hardened layer formed by the resulting hardened product can be endowed with high mechanical strength and adhesion strength. Cationic polymeric compositions may contain additives commonly used in curing compositions, as needed. These additives may include, for example, ion traps, antioxidants, chain transfer agents, polymerization accelerators (polyols, etc.), sensitizers, sensitizing aids, light stabilizers, tackifiers, thermoplastic resins, fillers, flow modifiers, plasticizers, defoamers, leveling agents, silane coupling agents, pigments, antistatic agents, and UV absorbers. Examples of free radical polymerizable compounds include compounds having vinyl unsaturated bonds. Besides (meth)acrylic acid compounds having one or more (meth)acrylic groups within the molecule, examples include vinyl compounds such as styrene, styrene sulfonic acid, vinyl acetate, vinyl propionate, and N-vinyl-2-pyrrolidone. (Methacrylamide) compounds are preferred as free radical polymerizable compounds. The second adhesive may contain one or more free radical polymerizable compounds. Examples of (meth)acrylic acid compounds include (meth)acrylate monomers having at least one (meth)acrylic acid group within the molecule, and (meth)acrylic acid oligomers having at least two (meth)acrylic acid groups within the molecule obtained by reacting two or more (meth)acrylamide monomers with a functional group. (Meth)acrylic acid oligomers are preferably (meth)acrylate oligomers having at least two (meth)acrylic acid groups within the molecule. (Meth)acrylic acid compounds may be used alone or in combination of two or more. Examples of (meth)acrylate monomers include monofunctional (meth)acrylate monomers having one (meth)acrylamide group, difunctional (meth)acrylate monomers having two (meth)acrylamide groups, and polyfunctional (meth)acrylate monomers having three or more (meth)acrylamide groups. Examples of monofunctional (meth)acrylate monomers include alkyl (meth)acrylates. In alkyl (meth)acrylates, the alkyl group can be straight-chain or branched if it has 3 or more carbon atoms. Specific examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, tributyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Furthermore, monofunctional (meth)acrylate monomers may also include aryl methacrylates such as benzyl methacrylate; terpene alcohol methacrylates such as isocamphenyl methacrylate; methacrylates with a tetrahydrofurfuryl structure such as tetrahydrofurfuryl methacrylate; methacrylates with cycloalkyl groups at the alkyl sites such as cyclohexyl methacrylate, cyclohexylmethyl methacrylate, dicyclopentyl acrylate, dicyclopentenyl methacrylate, and 1,4-cyclohexanediethanol monoacrylate; aminoalkyl methacrylates such as N,N-dimethylaminoethyl methacrylate; and methacrylates with ether bonds at the alkyl sites such as 2-phenoxyethyl methacrylate, dicyclopentenyloxyethyl methacrylate, ethyl carbitol methacrylate, and phenoxy polyethylene glycol methacrylate. Monofunctional (meth)acrylates with a hydroxyl group at the alkyl group or monofunctional (meth)acrylates with a carboxyl group at the alkyl group may also be used. Specific examples of monofunctional (meth)acrylates with a hydroxyl group at the alkyl group include 2-hydroxyethyl (meth)acrylate, 2- or 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, trimethylolpropane mono(meth)acrylate, and neopentyl terephthalol mono(meth)acrylate. Specific examples of monofunctional (meth)acrylates having a carboxyl group at the alkyl site include 2-carboxyethyl (meth)acrylate, ω-carboxy-polycaprolactone (n≒2) mono(meth)acrylate, 1-[2-(meth)propenyloxyethyl] phthalate, 1-[2-(meth)propenyloxyethyl] hexahydrophthalate, 1-[2-(meth)propenyloxyethyl] succinate, 4-[2-(meth)propenyloxyethyl] trimellitic acid, and N-(meth)propenyloxy-N',N'-dicarboxymethyl-p-phenylenediamine. The (meth)acrylamide monomer is preferably a (meth)acrylamide with a substituent at the N-position, typically an alkyl group, but which can form a ring together with the nitrogen atom of the (meth)acrylamide. This ring may have an oxygen atom as a ring member, in addition to the carbon atom and the nitrogen atom of the (meth)acrylamide. Furthermore, the carbon atom constituting the ring may be bonded to a substituent such as an alkyl group or a side oxygen group (=O). Specific examples of N-substituted (meth)acrylamides include N-alkyl (meth)acrylamides such as N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-n-butyl (meth)acrylamide, N-tert-butyl (meth)acrylamide, and N-hexyl (meth)acrylamide; and N,N-dialkyl (meth)acrylamides such as N,N-dimethyl (meth)acrylamide and N,N-diethyl (meth)acrylamide. Furthermore, the N-substituent can be an alkyl group having a hydroxyl group, examples of which include N-hydroxymethyl (meth)acrylamide, N-(2-hydroxyethyl)(meth)acrylamide, and N-(2-hydroxypropyl)(meth)acrylamide. Furthermore, specific examples of N-substituted (meth)acrylamides forming the aforementioned 5-membered or 6-membered rings include N-acrylpyrrolidine, 3-acryl-2- Azoxylone, 4-propenyl Phosphine, N-acrylpiperidine, N-methylacrylpiperidine, etc. Examples of functional (meth)acrylate monomers include alkyl diol di(meth)acrylate, polyoxyalkylene diol di(meth)acrylate, halogen-substituted alkyl diol di(meth)acrylate, aliphatic polyol di(meth)acrylate, hydrogenated dicyclopentadiene or tricyclodecanediol di(meth)acrylate, and di... Alkanediol or dialkyldiol Di(meth)acrylate of alkyldialkyl alcohols, di(meth)acrylate of epoxide adducts of bisphenol A or bisphenol F, and epoxy di(meth)acrylate of bisphenol A or bisphenol F, etc. More specific examples of 2-functional (meth)acrylate monomers include ethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, neopentyltetrol di(meth)acrylate, bis(trimethylolpropane di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and dipropylene glycol di(meth)acrylate. Acrylic esters, tripropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, polysiloxane di(meth)acrylate, neopentyl glycol hydroxytrimethylacetate di(meth)acrylate, 2,2-bis[4-(meth)propenyloxyethoxyethoxyphenyl]propane, 2,2-bis[4-(meth)propenyloxyethoxyethoxycyclohexyl]propane, hydrogenated dicyclopentadienyl di(meth)acrylate, tricyclodecanediethanol di(meth)acrylate, 1,3-di... Alkyl-2,5-diyldi(meth)acrylate (also known as dialkyl-2,5-dimethyl)acrylate) Alkanediol di(meth)acrylate, hydroxytrimethylacetaldehyde and trimethylolpropane acetal compound [chemical name: 2-(2-hydroxy-1,1-dimethylethyl)-5-ethyl-5-hydroxymethyl-1,3-diethyl-5-hydroxyacetaldehyde] Di(meth)acrylate of alkylene, tri(hydroxyethyl)isocyanurate di(meth)acrylate, etc. Representative examples of multifunctional (meth)acrylate monomers with 3 or more functions include glycerol trimethacrylate, alkoxylated glycerol trimethacrylate, trimethylolpropane trimethacrylate, bis(trimethylolpropane)trimethacrylate, bis(trimethylolpropane)tetramethacrylate, neopentyltetrol trimethacrylate, neopentyltetrol tetramethacrylate, dinepentyltetrol tetramethacrylate, dinepentyltetrol pentamethacrylate, and dinepentyltetrol pentamethacrylate. Poly(meth)acrylates of aliphatic polyols with three or more functions, such as neopentyl tetraol hexa(meth)acrylate, are also examples of poly(meth)acrylates of halogen-substituted polyols with three or more functions, tri(meth)acrylates of glycerol epoxide adducts, tri(meth)acrylates of trimethylolpropane epoxide adducts, 1,1,1-tris[(meth)acryloxyethoxyethoxy]propane, tri(hydroxyethyl)isocyanurate tri(meth)acrylate, etc. On the other hand, (meth)acrylic acid oligomers include ethyl carbamate (meth)acrylic acid oligomers, polyester (meth)acrylic acid oligomers, epoxy (meth)acrylic acid oligomers, etc. Ethyl carbamate (meth)acrylic acid oligomers refer to compounds having an ethyl carbamate bond (-NHCOO-) and at least two (meth)acrylic acid groups within the molecule. Specifically, they can be products of the ethyl carbamate reaction of a hydroxyl-containing (meth)acrylic acid monomer having at least one (meth)acrylic acid group and at least one hydroxyl group within the molecule with polyisocyanate, or products of the ethyl carbamate compound with an isocyanate terminal obtained by reacting a polyol with polyisocyanate and the ethyl carbamate reaction of a (meth)acrylic acid monomer having at least one (meth)acrylic acid group and at least one hydroxyl group within the molecule, etc. The hydroxyl-containing (meth)acrylate monomers used in the above-mentioned ethyl esterification reaction can be, for example, hydroxyl-containing (meth)acrylate monomers, including 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, glycerol di(meth)acrylate, trimethylolpropane di(meth)acrylate, neopentyltetrol tri(meth)acrylate, and dinepentyltetrol penta(meth)acrylate. Specific examples other than hydroxyl-containing (meth)acrylate monomers include N-hydroxyethyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, and other N-hydroxyalkyl (meth)acrylamide monomers. Examples of polyisocyanates for use in the ethyl esterification reaction with hydroxyl-containing (meth)acrylic acid monomers include hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate, xylene diisocyanate, diisocyanates obtained by hydrogenating aromatic isocyanates of these diisocyanates (e.g., hydrogenated toluene diisocyanate, hydrogenated xylene diisocyanate, etc.), triphenylmethane triisocyanate, dibenzylbenzene triisocyanate, and other di or triisocyanates, as well as polyisocyanates obtained by polymerizing the above diisocyanates. The polyols used to react with polyisocyanates to form ethyl carbamate compounds with isocyanate terminals can be aromatic, aliphatic, or alicyclic polyols. Polyester polyols and polyether polyols can also be used. Examples of aliphatic and alicyclic polyols include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, trimethylolpropane, bis(trimethylolpropane), neopentyl tertrol, dinepentyl tertrol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutyric acid, glycerol, and hydrogenated bisphenol A. Polyester polyols are obtained by the dehydration condensation reaction of the aforementioned polyols with polycarboxylic acids or their anhydrides. Examples of polycarboxylic acids or their anhydrides that can be anhydrides include succinic acid (anhydride), adipic acid, maleic acid (anhydride), icariin (anhydride), trimellitic acid (anhydride), pyrocalcite (anhydride), phthalic acid (anhydride), isophthalic acid, terephthalic acid, and hexahydrophthalic acid (anhydride). Besides polyalkylene glycols, polyether polyols can be polyoxyalkylene modified polyols obtained by reacting the above-mentioned polyols or dihydroxybenzenes with epoxides. Polyester (meth)acrylic acid oligomers are compounds containing ester bonds and at least two (meth)acrylamide groups (typically (meth)acryloxy) groups within their molecules. Specifically, they are obtained by a dehydration condensation reaction of (meth)acrylic acid, polycarboxylic acids or their anhydrides, and polyols. If an anhydride is used, it is indicated by the suffix "(anhydride)". Examples of polycarboxylic acids or their anhydrides used in dehydration condensation reactions include succinic acid (anhydride), adipic acid, maleic acid (anhydride), itconic acid (anhydride), trimellitic acid (anhydride), pyrocalcite (anhydride), hexahydrophthalic acid (anhydride), phthalic acid (anhydride), isophthalic acid, and terephthalic acid. Furthermore, examples of polyols used in dehydration condensation reactions include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, trimethylolpropane, bis(trimethylolpropane), neopentyl tertrol, dinepentyl tertrol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutyric acid, glycerol, and hydrogenated bisphenol A. Epoxy (meth)acrylic acid oligomers can be obtained, for example, by the addition reaction of polyoxypropylene ether with (meth)acrylic acid, and have at least two (meth)acrylic acid ions in the molecule. Examples of polyoxypropylene ethers used in the addition reaction include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and bisphenol A diglycidyl ether. In the second adhesive, the polymeric compound may consist only of a free radical polymeric compound, or it may further contain a cationic polymeric compound. When the second adhesive contains a free radical polymerizable compound, it is preferable to further contain a free radical polymerization initiator. The free radical polymerization initiator is preferably a photoradical polymerization initiator. A photoradical polymerization initiator may be used alone or in combination of two or more. Examples of photoradical polymerization initiators include acetophenone, 3-methylacetophenone, diphenyl ethylene glycol dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, and 2-methyl-1-[4-(methylthio)phenyl-2-N- Acetophenone-based initiators such as linylpropane-1-one and 2-hydroxy-2-methyl-1-phenylpropane-1-one; diphenyl ketone-based initiators such as diphenyl ketone, 4-chlorodiphenyl ketone, and 4,4'-diaminodiphenyl ketone; benzoyl ether-based initiators such as benzoyl propyl ether and benzoyl ethyl ether; thioxanthone-based initiators such as 4-isopropylthioxanthone; and others can be cited. Ketones, fumonisins, camphorquinones, benzaldehyde, anthraquinones. The amount of photoradical polymerization initiator added is typically 0.5 to 20 parts by weight, preferably 1 to 6 parts by weight, relative to 100 parts by weight of the free radical polymerizable compound. By adding more than 0.5 parts by weight of the photoradical polymerization initiator, the free radical polymerizable compound can be sufficiently hardened, imparting high mechanical strength and adhesion strength to the resulting polarizing plate. On the other hand, excessive amounts may reduce the durability of the polarizing plate. <Layer containing urea compounds> When urea compounds are included in the adhesive layer as described above, there are no limitations. From the viewpoint of improving the high-temperature durability of the polarizing plate, they can also be included in other layers besides the adhesive layer. In polarizing plates with a transparent protective film on only one side, from the viewpoint of improving physical strength, a hardening layer can be applied to the opposite side of the transparent protective film of the polarizing element. In this embodiment, the hardened layer may also contain a urea-based compound to form a urea-based compound layer. Normally, the hardened layer is formed from a hardening composition containing an organic solvent, but paragraphs

[0020] to

[0042] of Japanese Patent Application Publication No. 2017-075986 describe a method for forming the hardened layer from an aqueous solution of an active energy line hardening polymer composition. The composition may also contain a water-soluble urea-based compound. The layer containing a urea compound preferably has at least one urea compound and an adhesive. Examples of adhesives include polymer adhesives, thermosetting resin adhesives, and active energy line curing resin adhesives; any of these adhesives may be preferred. The thickness of the urea-containing compound layer is preferably 0.1 μm to 20 μm, more preferably 0.5 μm to 15 μm, and even more preferably 1 μm to 10 μm. [Manufacturing Method of Polarizing Plate] The method for manufacturing a polarizing plate according to this embodiment may include a moisture content adjustment step and a lamination step. In the moisture content adjustment step, the moisture content of the polarizing element or polarizing plate is adjusted to be above the equilibrium moisture content at 20°C and 40% relative humidity and below the equilibrium moisture content at 20°C and 60% relative humidity. The moisture content of the polarizing element or polarizing plate can be adjusted according to the above-mentioned moisture content. In the lamination step, the polarizing element and the transparent protective film are laminated with a first adhesive layer in between. Furthermore, in the lamination step, the transparent protective film and the retardation layer are laminated with a second adhesive layer in between. The lamination order is not limited. For example, in the lamination step, the retardation layer and the transparent protective film are bonded with a second adhesive layer in between, and the transparent protective film side of the resulting laminate and the polarizing element are bonded with a first adhesive layer in between. The order of the moisture content adjustment step and the lamination step is not limited, and the moisture content adjustment step and the lamination step may also be performed simultaneously. [Composition of an image display device] The polarizing plate of this invention is used in various image display devices such as liquid crystal display devices or organic EL display devices. The interlayer filling configuration involves both sides of the polarizing plate contacting layers other than the air layer, specifically, contacting solid layers such as adhesive layers. When the image display device has an interlayer filling configuration, the transmittance tends to decrease at high temperatures. In the image display device using the polarizing plate of this embodiment, even with an interlayer filling configuration, the decrease in transmittance of the polarizing plate at high temperatures can be suppressed. An example image display device may have an image display unit, a first adhesive layer deposited on the visual confirmation side surface of the image display unit, and a polarizing plate deposited on the visual confirmation side surface of the first adhesive layer. This image display device may further have a second adhesive layer deposited on the visual confirmation side surface of the polarizing plate, and a transparent member deposited on the visual confirmation side surface of the second adhesive layer. The polarizing plate of the present invention is suitable for use in an image display device having an interlayer filling configuration in which a transparent member is disposed on the visual confirmation side of the image display device, the polarizing plate and the image display unit are bonded by a first adhesive layer, and the polarizing plate and the transparent member are bonded by a second adhesive layer. In this specification, either or both of the first and second adhesive layers are referred to simply as "adhesive layers". Furthermore, the member used for bonding the polarizing plate to the image display unit, and the member used for bonding the polarizing plate to the transparent member, is not limited to an adhesive layer and may also be an adhesive layer. <Image Display Unit> Image display units can include liquid crystal units (LCDs) or organic EL units (OLEDs). The liquid crystal unit can be any of the following: a reflective liquid crystal unit utilizing external light, a transmissive liquid crystal unit utilizing light from a light source such as a backlight, or a semi-transmissive / semi-reflective liquid crystal unit utilizing both external light and light from a light source. When the liquid crystal unit utilizes light from a light source, in the image display device (liquid crystal display device), a polarizing plate is also disposed on the opposite side of the visual confirmation side of the image display unit (liquid crystal unit), and a light source is further disposed thereon. The polarizing plate on the light source side and the liquid crystal unit are preferably bonded together with a suitable adhesive layer. The driving method of the liquid crystal unit can be any type, such as VA mode, IPS mode, TN mode, STN mode, or bent alignment (π type). Organic EL units are suitable for use on transparent substrates where transparent electrodes, organic light-emitting layers, and metal electrodes are sequentially deposited to form a light-emitting body (organic electroluminescent light-emitting body). The organic light-emitting layer is a stack of various organic thin films. For example, it can be a stack of a hole injection layer composed of triphenylamine derivatives and a light-emitting layer composed of an anthracene fluorescent organic solid, or a stack of such light-emitting layers and an electron injection layer composed of perylene derivatives, or a stack of a hole injection layer, a light-emitting layer and an electron injection layer, etc. <Lamination of image display unit and polarizing plate> An adhesive layer (adhesive sheet) is suitable for bonding the image display unit to the polarizing plate. From an operability perspective, a preferred method is to bond the image display unit to the polarizing plate, which has an adhesive layer attached to one side of the polarizing plate. The adhesive layer can be applied to the polarizing plate in a suitable manner. Examples include dissolving or dispersing the base polymer or its components in a solvent composed of a single substance or mixture of suitable solvents such as toluene or ethyl acetate, preparing an adhesive solution of approximately 10% to 40% by mass, and directly applying it to the polarizing plate using a suitable spreading method such as casting or coating; or forming an adhesive layer on a separator and transferring it to the polarizing plate. <Adhesive layer> The adhesive layer may consist of one or more layers, preferably one layer. The adhesive layer may be composed of an adhesive composition primarily composed of (meth)acrylic resins, rubber resins, ethyl carbamate resins, ester resins, polysiloxane resins, or polyvinyl ether resins. Preferably, the adhesive composition is based on an (meth)acrylic resin with excellent transparency, weather resistance, and heat resistance. The adhesive composition may be of the active energy linear curing type or the thermosetting type. The (meth)acrylate resin (base polymer) used in the adhesive composition is suitable as a polymer or copolymer with one or more (meth)acrylate monomers such as butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. The base polymer is preferably a copolymer of polar monomers. Examples of polar monomers include (meth)acrylate compounds, 2-hydroxypropyl (meth)acrylate compounds, hydroxyethyl (meth)acrylate compounds, (meth)acrylamide compounds, N,N-dimethylaminoethyl (meth)acrylate compounds, and glycidyl (meth)acrylate compounds, which possess carboxyl, hydroxyl, amide, amino, or epoxy groups. The adhesive composition may contain only the aforementioned basic polymer, but typically further includes a crosslinking agent. The crosslinking agent is a divalent or higher metal ion, such as a metal ion that forms a carboxylic acid metal salt with a carboxyl group, a polyamine compound that forms an amide bond with a carboxyl group, a polyepoxide compound or polyol that forms an ester bond with a carboxyl group, or a polyisocyanate compound that forms an amide bond with a carboxyl group. Polyisocyanate compounds are preferred. Active energy line curing adhesive compositions possess the property of curing upon irradiation with active energy lines such as ultraviolet light or electron beams. They also exhibit adhesiveness before irradiation and can adhere tightly to substrates such as films, and can be cured and have their adhesion adjusted by irradiation with active energy lines. Ultraviolet curing types are preferred for active energy line curing adhesive compositions. In addition to the base polymer and crosslinking agent, active energy line curing adhesive compositions may further contain polymerizable compounds with active energy lines. Photopolymerization initiators and photosensitizers may be included as needed. The adhesive composition may contain additives such as microparticles, beads (resin beads, glass beads, etc.), glass fibers, resins other than the base polymer, adhesive agents, fillers (metal powder or other inorganic powders, etc.), antioxidants, ultraviolet absorbers, dyes, pigments, colorants, defoamers, corrosion inhibitors, and photopolymerization initiators to impart light scattering properties. The adhesive layer can be formed by coating a diluted organic solvent solution of the adhesive composition onto the surface of a substrate film, image display unit, or polarizing plate and then drying it. The substrate film is generally a thermoplastic resin film, and a typical example is a release membrane that has undergone a release treatment. For example, the release membrane may be a film made of resins such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, or polyarylate, on the adhesive layer forming surface, which has undergone a release treatment such as polysiloxane treatment. An adhesive composition can be directly coated onto the release surface of the separation membrane to form an adhesive layer, and the adhesive layer with the separation membrane attached can be deposited onto the surface of the polarizer. Alternatively, an adhesive composition can be directly coated onto the surface of the polarizer to form an adhesive layer, and a separation membrane can be deposited on the outer surface of the adhesive layer. When the adhesive layer is applied to the surface of the polarizing plate, it is preferable to perform surface activation treatments such as plasma treatment or corona treatment on the bonding surface of the polarizing plate and / or the bonding surface of the adhesive layer, and more preferably to perform corona treatment. Alternatively, an adhesive composition can be coated onto the second separation membrane to form an adhesive layer, and a separation membrane can be deposited on the formed adhesive layer to form an adhesive sheet. After the second separation membrane is peeled off from the adhesive sheet, the adhesive layer with the separation membrane attached is deposited on the polarizing plate. The second separation membrane is one that has a weaker adhesion between the separation membrane and the adhesive layer and is easier to peel off. There is no particular limitation on the thickness of the adhesive layer. For example, it is preferably 1μm to 100μm, more preferably 3μm to 50μm, and can also be 20μm or more. <Transparent Components> Transparent components disposed on the visual confirmation side of an image display device can include transparent panels (window layers) or touch panels. The transparent panel can be a transparent panel with appropriate mechanical strength and thickness. Examples of transparent panels include transparent resin panels made of polyimide-based resin, acrylic resin, or polycarbonate resin, or glass panels. Functional layers such as anti-reflective layers can also be laminated on the visual confirmation side of the transparent panel. Furthermore, when the transparent panel is a transparent resin panel, a hard coating layer can be laminated to improve physical strength, or a low-permeability layer can be laminated to reduce moisture permeability. Touch panels can use various types of touch panels, such as resistive film, capacitive, optical, and ultrasonic touch panels, or glass panels or transparent resin panels with touch sensor functionality. When a capacitive touch panel is used as the transparent component, it is preferable to place a transparent panel made of glass or transparent resin panel further away from the visual confirmation side than the touch panel. <Bonding of polarizing plate and transparent component> The bonding of the polarizing plate to the transparent component is suitable for using adhesives or active energy line curing adhesives. When using adhesives, the adhesive can be applied in an appropriate manner. Specific application methods include, for example, the adhesive layer application method used in the aforementioned bonding of the image display unit to the polarizing plate. When using an active energy line curing adhesive, to prevent the adhesive solution from spreading before curing, the following method is suitable: a weir is set up to surround the edge of the image display panel; a transparent component is placed on the weir; and the adhesive solution is injected. After injecting the adhesive solution, alignment and degassing are performed as needed, followed by irradiation with active energy lines for curing. (Example) The present invention will be specifically described below with reference to the embodiments. The materials, reagents, quantities and proportions, operations, etc. shown in the following embodiments may be appropriately modified without departing from the spirit of the present invention. Therefore, the present invention is not limited to the following embodiments. (1) Measurement of the thickness of the polarizing element: Measurements were taken using a digital micrometer "MH-15M" manufactured by Nikon Corporation. (2) Measurement of the polarization degree, transmittance of the polarizing element, and hue of the polarizing plate: Measurements were taken using a spectrophotometer with an integrating sphere (V7100, manufactured by Japan Spectrophotometer Co., Ltd., 2-degree field of view; C light source). (3) Determination of boron content: 0.2 g of the polarizing element was dissolved in 200 g of a 1.9% (w / w) mannitol aqueous solution. The resulting aqueous solution was then titrated with a 1 mole / L sodium hydroxide aqueous solution. By comparing the amount of sodium hydroxide solution required for neutralization and the calibration curve, the boron content of the polarizing element was calculated. (4) Determination of zinc ion content: Nitric acid was added to the polarizing element of a precision-balanced apparatus, and acid decomposition was performed using a microwave sample pretreatment device (Milestone General Corporation, "ETHOS D"). The resulting solution was used as the assay solution. The zinc ion content was quantitatively determined using an ICP-OES instrument (Agilent Technologies, "5110 ICP-OES"), and the zinc mass relative to the mass of the polarizing element was calculated. (5) Determination of boron adsorption rate of PVA-based resin membranes: A PVA-based resin membrane, cut to 100 mm on all four sides, was immersed in pure water at 30°C for 60 seconds, followed by immersion in an aqueous solution containing 5 parts boric acid at 60°C for 120 seconds. The PVA-based resin membrane removed from the boric acid aqueous solution was dried in an oven at 80°C for 11 minutes. After conditioning at 23°C and 55% RH for 24 hours, a boron-containing PVA membrane was obtained. 0.2 g of the obtained boron-containing PVA-based resin membrane was dissolved in 200 g of a 1.9% (w / w) mannitol aqueous solution. This aqueous solution was titrated with a 1 mole / L sodium hydroxide aqueous solution. By comparing the required amount of sodium hydroxide solution for neutralization and using a calibration curve, the boron content of the PVA-based resin membrane was calculated. The boron content of the obtained PVA-based resin membrane was taken as the boron adsorption rate of the PVA-based resin membrane. [Fabrication of Polarizing Components] A 30 μm thick polyvinyl alcohol (PVA) resin film with a boron adsorption rate of 5.71% by mass was prepared. The PVA resin film was immersed in pure water at 21.5 °C for 79 seconds (swelling treatment). It was then immersed in an aqueous solution containing 1.0 mM iodine at 23 °C for 151 seconds (dyeing step). Subsequently, it was immersed in an aqueous solution containing 2.5 / 4 / 100 potassium iodide / boric acid / water at 68.5 °C for 76 seconds (first crosslinking step). Next, it was immersed in an aqueous solution containing 3 / 5.5 / 0.6 / 100 potassium iodide / boric acid / zinc chloride / water at 45 °C for 11 seconds (second crosslinking step, metal ion treatment step). Finally, it was immersed in a washing bath and washed (washing step), and dried at 38 °C (drying step). A 12 μm thick polarizing element with iodine adsorbed and aligned in PVA was obtained by the above method. The elongation was mainly carried out during the dyeing and first cross-linking steps, with a total elongation of 5.85 times. The resulting polarizing element contained 0.17% zinc ions and 4.62% boron by mass. Fabrication of a retardation film with a retardation layer Mix 5 parts of the photoalignment material with the following structure (weight average molecular weight of 30,000) and 95 parts of cyclopentanone as a solvent, and stir at 80°C for 1 hour to obtain composition A for alignment film formation. Polymerizable liquid crystal compound A and polymerizable liquid crystal compound B, as shown below, were mixed at a mass ratio of 90:10. 1.0 part of a leveling agent (DIC Corporation's "F-556") and 2-dimethylamino-2-benzyl-1-(4-) polymerizing initiator were added to the mixture. Six parts of linylphenyl butane-1-one [BASF JAPAN Co., Ltd. "IRGACURE369 (Irg369)"] were added. Additionally, N-methyl-2-pyrrolidone (NMP) was added to a solids concentration of 13%, and the mixture was stirred at 80°C for 1 hour to obtain composition A for forming a liquid crystal curing film. Polymerizable liquid crystal compound A was manufactured according to the method described in Japanese Patent Application Publication No. 2010-31223. Polymerizable liquid crystal compound B was manufactured according to the method described in Japanese Patent Application Publication No. 2009-173893. The molecular structures of each compound are shown below. (Polymerizable liquid crystal compound A) (Polymerizable liquid crystal compound B) A cyclic olefin membrane (ZF-14-50, manufactured by ZEON Corporation, Japan) with a thickness of 50 μm and a length of 300 mm × width, is prepared as the substrate and cut to a size of 300 mm × 200 mm. Its moisture permeability is 7 g / m². 2 [24hr]. After corona treatment on the substrate, composition A for alignment film formation is applied using a bar coater with a coating width of 180mm (10mm uncoated portion at both ends). The coating is dried at 80°C for 1 minute and then irradiated using a polarized UV irradiation device [USHIO Electric Co., Ltd. "SPOT CURE SP-9"] at a wavelength of 313nm with a cumulative light intensity of 100mJ / cm. 2 Polarized UV exposure was performed at an axial angle of 0° (long side reference). Liquid crystal curing film composition A was coated onto the formed alignment film using a bar coater. After drying the coating at 120°C for 1 minute, it was irradiated with ultraviolet light (500 mJ / cm² at a wavelength of 365 nm under nitrogen conditions) using a high-pressure mercury lamp (USHIO Electric Co., Ltd. "uniQure VB-15201BY-A"). 2 This process hardens the liquid crystal compound, forming a first liquid crystal hardened layer. The first liquid crystal hardened layer is a positive A-plate. A laminate A consisting of a substrate, an alignment film, and a first liquid crystal hardened layer is obtained using the above method. The phase difference and wavelength dispersion characteristics of the first liquid crystal curing layer were measured. The first liquid crystal curing layer of laminate A was bonded to glass with an adhesive and then the substrate was peeled off. The phase difference Re(550) = 130 nm, Rth(550) = 65 nm, Re(450) / Re(550) = 0.86, and Re(650) / Re(550) = 1.04. Composition B for alignment film formation was obtained by adding 2-butoxyethanol to a commercially available alignment polymer (SUNEVER SE-610 manufactured by Nissan Chemical Co., Ltd.). A mixture was prepared by mixing a polymerizable liquid crystal compound (BASF's "LC242") with the following chemical formula as shown below (19.2%), a polymerization initiator (BASF JAPAN's "IRGACURE 907") (registered trademark), a leveling agent (BYK JAPAN's "BYK361N") (1.1%), a reaction additive (BASF's "Laromer LR-9000") (registered trademark), and propylene glycol 1-monomethyl ether 2-acetate as a solvent (79.1%). The mixture was stirred at 80°C for 1 hour and then cooled to room temperature to obtain composition B for forming a liquid crystal curing film. The surface of the first liquid crystal curing layer of the laminate A was subjected to a first corona treatment at an output of 0.3 kW and a processing speed of 3 m / min. Alignment film formation composition B was then coated onto the corona-treated surface using a bar coater and dried at 90°C for 1 minute. The thickness of the formed alignment film was measured to be 34 nm using a laser microscope. Liquid crystal curing film formation composition B was then coated onto the resulting alignment film using a bar coater. After drying the coating at 90°C for 1 minute, the film was irradiated with ultraviolet light (in a nitrogen environment, the cumulative light intensity at a wavelength of 365 nm was 1000 mJ / cm²) using a high-pressure mercury lamp. 2 This process forms a second liquid crystal curing layer, which is a positive C-plate. A phase retardation film consisting of two curing layers of polymeric liquid crystal compounds deposited on a substrate is thus obtained. The phase difference and wavelength dispersion characteristics of the formed phase retardation layers (first and second liquid crystal curing layers) were measured. The second liquid crystal curing layer side of the phase retardation film was bonded to glass with an adhesive, and the substrate was then peeled off. The phase difference Re(550) = 130 nm, Rth(550) = -45 nm, Re(450) / Re(550) = 0.86, and Re(650) / Re(550) = 1.04. [Second Adhesive] After mixing the following compounds and degassing, a second adhesive A of UV-curable type is prepared. (Photocationic hardening compound) 70 parts of 3,4-epoxycyclohexanecarboxylic acid methyl 3,4-epoxycyclohexyl ester; 20 parts of neopentyl glycol diglycidyl ether; 10 parts of 2-ethylhexyl glycidyl ether. (Photocationic polymerization initiator) 2.25 parts of triarylstrom hexafluorophosphate. The photocationic polymerization initiator was formulated as a 50% propyl carbonate solution, and the above formulation amount was its solid content. The following compound was stirred at 50°C for 1 hour to prepare UV-curable type 2 adhesive B. (Photoradical hardening compounds) 38.5 parts by weight of hydroxyethyl acrylamide (manufactured by Xingren Co., Ltd.); 20.0 parts by weight of tripropylene glycol diacrylate (manufactured by Dong-A Synthetic Co., Ltd., "aronix M-220"); Acrylic Phosphorus (manufactured by Xingren Co., Ltd.) 38.5 parts by weight. (Photoradical polymerization initiator) 1.5 parts by weight of diethylthioxanone (KAYACURE DETX-S manufactured by Nippon Kayaku Co., Ltd.); 2-Methyl-1-(4-methylthiophenyl)-2-N- 1.5 parts by weight of linylpropane-1-one [BASF "IRGACURE 907"]. [Transparent Protective Film] Commercially available cellulose ester membrane (FUJIFILM Co., Ltd. "fujitac ZRD40", membrane thickness 40μm) is prepared as a transparent protective film. [A laminate containing a transparent protective film, a second adhesive layer, and a phase reversal layer] A transparent protective film (1.5 μm thick) is laminated across the liquid crystal curing layer side of the retardation film, separated by a second adhesive A. Corona treatment is applied to each bonding surface before lamination. An ultraviolet irradiation device (using a "D valve" lamp manufactured by Fusion UV Systems) is used from the transparent protective film side to accumulate a light intensity of 250 mJ / cm². 2 The second adhesive A is cured by irradiating it with ultraviolet light. A laminate 1 having a transparent protective film, a second adhesive layer A, a phase retardation layer and a substrate in sequence is produced by the above method. A transparent protective film (1.0 μm thick) is laminated across the liquid crystal curing layer side of the retardation film, separated by a second adhesive B. Corona treatment is performed on each bonding surface before lamination. An ultraviolet irradiation device (using a "V valve" lamp manufactured by Fusion UV Systems) is used from the transparent protective film side to accumulate a light intensity of 1000 mJ / cm². 2 The second adhesive B is cured by irradiating it with ultraviolet light. A laminate 2 having a transparent protective film, a second adhesive layer B, a phase retardation layer and a substrate in sequence is produced by the above method. Laminated bodies 1 and 2 were immersed in a 1.5 mol / L sodium hydroxide aqueous solution (saponification solution) maintained at 55°C for 2 minutes and then washed with water. Next, the laminates were immersed in a 0.05 mol / L sulfuric acid aqueous solution at 25°C for 30 seconds, followed by running water (water bath) for 30 seconds to neutralize the membrane. This process was repeated three times using an air knife for drainage. The laminates were then dried in a drying oven at 70°C for 15 seconds to obtain saponified laminates 1 and 2. [First Adhesive] 50g of modified PVA resin containing acetyl groups (GOHSENEX Z-410 manufactured by Mitsubishi Chemical Corporation) was dissolved in 950g of pure water. After heating at 90°C for 2 hours, the solution was cooled to room temperature to obtain a PVA solution for adhesives. Adhesives A to C were prepared by mixing PVA solution, urea, a commercially available 40% glyoxal solution, maleic acid, and pure water in the amounts shown in Table 1. Adhesives A and B contain urea compounds, while adhesive C does not contain urea compounds. [Table 1] [Making of Polarizing Plates] A commercially available cellulose ester membrane (FUJIFILM Co., Ltd. "TJ40UL", membrane thickness 40μm) was immersed in a 1.5mol / L sodium hydroxide aqueous solution (saponification solution) maintained at 55°C for 2 minutes, and then washed with water. Next, the membrane was immersed in a 0.05mol / L sulfuric acid aqueous solution at 25°C for 30 seconds, and then rinsed under running water (water bath) for 30 seconds to neutralize the membrane. This process was repeated three times by draining with an air knife. The membrane was then dried in a drying oven at 70°C for 15 seconds to prepare saponified membrane A. Saponified membrane A was deposited on the opposite side of the phase retardation layer of the polarizing element. A saponified film A is bonded to one side of a polarizing element using a roller laminator through a first adhesive A, and the transparent protective film side of the saponified laminate 1 is bonded to the other side of the polarizing element. The laminate is dried at 80°C for 5 minutes to obtain a polarizing plate 1. The adhesive layer is adjusted to a thickness of 50 nm on both sides after drying. The polarizing plate 1 comprises a transparent protective film, a first adhesive A layer, a polarizing element, a first adhesive A layer, a transparent protective film, a second adhesive layer, a retardation layer, and a substrate. In the manufacturing steps of polarizing plate 1, polarizing plates 2 and 4 are obtained by changing the first adhesive A to the first adhesive B or C. In the manufacturing steps of polarizing plates 1 and 4, polarizing plates 3 and 5 are obtained by replacing the saponified laminate 1 with the saponified laminate 2. The combination of adhesive layers contained in the polarizing plates is shown in Table 2. Adjustment of moisture content in polarizing plates (polarizing elements) Polarizing plates 1 to 5 were stored for 72 hours at a temperature of 20°C and relative humidity of 30%, 35%, 40%, 45%, 50%, or 55%. The moisture content was determined using the Karl Fischer method at 66, 69, and 72 hours of storage. Under any humidity condition, the moisture content values ​​remained unchanged at 66, 69, and 72 hours. Therefore, the moisture content of polarizing plates 1 to 5 can be considered the same as the equilibrium moisture content after 72 hours. When the moisture content of a polarizing plate reaches equilibrium under a given storage environment, it can be assumed that the moisture content of the polarizing element within the polarizing plate also reaches equilibrium under that same environment. Polarizing plates 1 to 5 were stored at 20°C and 55% relative humidity for 72 hours, and the moisture content of the polarizing plates was adjusted to the equilibrium moisture content of the environment at 20°C and 55% relative humidity. <High Temperature Durability Assessment> [Preparation of Evaluation Samples] After peeling the substrate from polarizing plates 1 to 5 with adjusted moisture content, an acrylic adhesive (LINTEC Corporation "#7") was applied to both sides. The polarizing plates were cut into 50mm × 100mm pieces with the absorption axis parallel to the long side, and alkali-free glass (Corning Corporation "EAGLE XG") was laminated onto the adhesive surfaces. This laminate was used as the evaluation sample. [Single monomer transmittance evaluation (105℃)] The evaluation samples will be subjected to a temperature of 50℃ and a pressure of 5 kgf / cm². 2After autoclaving at (490.3 kPa) for 1 hour, the samples were placed in an environment of 23°C and 55% relative humidity for 24 hours. The transmittance of each evaluation sample was then measured and used as the initial value. The samples were then stored at 105°C, and the transmittance of the evaluation samples was measured every 50 hours for 100 to 200 hours. The time it took for the transmittance to decrease by more than 5% relative to the initial value was evaluated using the following criteria. The results are presented in Table 2. A. If the transmittance decreases to below 5% after 200 hours: Those whose transmittance decreases to more than 5% after 150 to 200 hours: B. C. Those whose transmittance decreases to more than 5% after 100 to 150 hours: Those whose transmittance decreases to more than 5% after 100 hours: D. [Evaluation of Orthogonal Light Leakage] After measuring the monomer transmittance after 200 hours according to the above-mentioned monomer transmittance evaluation, orthogonal light leakage was evaluated using the evaluation sample. The evaluation polarizing plate and the evaluation sample, which were not placed in a heated environment, were arranged in a manner resembling orthogonal polarizers and placed on a backlight. The surrounding light was blocked, and orthogonal light leakage was visually evaluated using the following criteria. The results are presented in Table 2. Furthermore, the monomer transmittance evaluation was not performed on evaluation samples other than A due to coloration caused by polyolefination. No orthogonal light leakage was observed in group A. Almost no orthogonal light leakage was observed in B. Those who slightly observed orthogonal light leakage: C. Those who clearly observed orthogonal light leakage: D. [Table 2] In a polarizing plate having a phase retardation layer comprising a hardened layer of a polymerizable liquid crystal compound, when the first adhesive layer is formed from an adhesive containing a urea compound, the decrease in transmittance can be suppressed even when the polarizing plate is exposed to a high temperature of 105°C. Furthermore, the decrease in transmittance can be suppressed even when the polarizing plate has an interlayer filling configuration. When the first adhesive contains a urea compound, the case where the second adhesive contains a cationic polymeric compound tends to suppress orthogonal light leakage compared to the case where it contains a free radical polymeric compound. This invention provides a polarizing plate with excellent high-temperature durability. Furthermore, when the first adhesive does not contain a urea compound, the case where the second adhesive contains a cationic polymeric compound is more prone to a decrease in monomer transmittance compared to the case where it contains a free radical polymeric compound (polarizing plates 4 and 5).

Claims

1. A polarizing plate comprising, sequentially, a polarizing element having a dichroic pigment adsorbed and aligned on a polyvinyl alcohol-based resin layer, a transparent protective film, and a retardation layer, wherein the polarizing element and the transparent protective film are bonded together by a first adhesive layer formed by a first adhesive containing a urea compound, and the transparent protective film and the retardation layer are bonded together by a second adhesive layer formed by a second adhesive of an active energy line curing type, wherein the urea compound is at least one selected from the group consisting of urea, urea derivatives, thiourea, and thiourea derivatives, wherein the retardation layer has a curing layer of a polymerizable liquid crystal compound, wherein the polarizing element is in direct contact with the first adhesive layer, wherein the first adhesive is an aqueous adhesive, and wherein the second adhesive contains a cationic polymerizable compound.

2. The polarizing plate as described in claim 1, wherein, The aforementioned urea compounds are selected from at least one urea compound in the group consisting of urea derivatives and thiourea derivatives.

3. The polarizing plate as described in claim 1 or 2, wherein, The aforementioned first adhesive contains a polyvinyl alcohol-based resin.

4. The polarizing plate as described in claim 1 or 2, wherein, The aforementioned phase retardation layer consists of two hardened layers of polymeric liquid crystal compound in direct contact.

5. The polarizing plate as described in claim 1 or 2, wherein, The aforementioned phase difference layer has a positive C plate and a positive A plate.

6. The polarizing plate as described in claim 1 or 2, wherein, The aforementioned cationic polymerizable compound contains at least one compound selected from the group consisting of alicyclic epoxides and aliphatic epoxides.

7. The polarizing plate as claimed in claim 1 or 2, wherein the aforementioned transparent protective film is provided on both sides of the aforementioned polarizing element.

8. The polarizing plate as described in claim 1 or 2, wherein, The moisture content of the aforementioned polarizing plate is above the equilibrium moisture content at 20°C and 40% relative humidity, and below the equilibrium moisture content at 20°C and 60% relative humidity.

9. An image display device comprising a polarizing plate as described in any one of claims 1 to 8.