JP7411520B2 - Polarizing plate, polarizing plate with retardation layer, and organic electroluminescent display device - Google Patents

Description

The present invention relates to a polarizing plate, a polarizing plate with a retardation layer, and an organic electroluminescent (EL) display device.

In recent years, with the spread of thin displays, displays equipped with organic EL panels (organic EL display devices) have been proposed. Since an organic EL panel has a highly reflective metal layer, problems such as reflection of external light and background reflection are likely to occur. Therefore, it is known that these problems can be prevented by providing a circularly polarizing plate on the viewing side (for example, Patent Documents 1 to 3). However, there is a problem in that the circularly polarizing plate (substantially, the polarizing plate included in the circularly polarizing plate) provided in the organic EL display device is easily decolored.

Japanese Patent Application Publication No. 2003-311239 Japanese Patent Application Publication No. 2002-372622 Patent No. 3325560

The present invention has been made to solve the above-mentioned conventional problems, and its main purpose is to provide a polarizing plate and a polarizing plate with a retardation layer in which decolorization is significantly suppressed when applied to an organic EL display device. It's about doing.

A polarizing plate according to an embodiment of the present invention includes a polyvinyl alcohol resin layer, a protective layer provided on a visible side of the polyvinyl alcohol resin layer, and a protective layer disposed on a side opposite to the visible side of the polyvinyl alcohol resin layer. An adhesive layer. The polyvinyl alcohol resin layer includes a first polyvinyl alcohol resin layer that functions as a polarizer, and a second polyvinyl alcohol resin layer provided on the viewing side of the first polyvinyl alcohol resin layer. include. The thickness of the second polyvinyl alcohol resin layer is 0.03 μm to 2 μm; the boric acid concentration on the surface of the polyvinyl alcohol resin layer opposite to the viewing side is higher than the boric acid concentration on the viewing side surface; And the difference is 0.3% by weight or more; the moisture permeability of the protective layer on the viewing side is 200 g/m ² ·24 h or more.
In one embodiment, the boric acid concentration of the first polyvinyl alcohol resin layer is 14% by weight or more.
In one embodiment, the first polyvinyl alcohol resin layer has a single transmittance of _42.5 % or more; _a ratio (A ₅₅₀ /A ₂₁₀ ) is 1.4 or more; the ratio of the orthogonal absorbance A ₄₇₀ at a wavelength of 470 nm to the orthogonal absorbance A ₆₀₀ at a wavelength of 600 nm (A ₄₇₀ /A ₆₀₀ ) is 0.7 or more; and the orthogonal b The value is greater than -10.
In one embodiment, the iodine concentration of the polarizer is between 2% and 10% by weight.
In one embodiment, the polarizing plate has an absolute value of change in polarization degree |ΔP| of 50% or less when exposed to ammonia vapor for 2 hours in a 60° C. environment.
According to another aspect of the present invention, a polarizing plate with a retardation layer is provided. This polarizing plate with a retardation layer includes the above polarizing plate and a retardation layer.
According to yet another aspect of the invention, an organic electroluminescent display device is provided. This organic electroluminescent display device includes the above polarizing plate or the above polarizing plate with a retardation layer.

According to an embodiment of the present invention, in the polyvinyl alcohol resin layer of the polarizing plate, the second polyvinyl alcohol resin layer is provided adjacent to the first polyvinyl alcohol resin layer that functions as a polarizer, and the second polyvinyl alcohol resin layer is provided adjacent to the first polyvinyl alcohol resin layer that functions as a polarizer. By providing a concentration gradient such that the boric acid concentration on the visible side surface of the polyvinyl alcohol resin layer is smaller than the boric acid concentration on the surface opposite to the visible side of the first polyvinyl alcohol resin layer by a predetermined value, When applied to an organic EL display device, it is possible to realize a polarizing plate and a polarizing plate with a retardation layer in which decolorization is significantly suppressed.

1 is a schematic cross-sectional view of a polarizing plate according to one embodiment of the present invention.

Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

A. Polarizing plate A-1. Overall Configuration of Polarizing Plate FIG. 1 is a schematic cross-sectional view of a polarizing plate according to one embodiment of the present invention. The illustrated polarizing plate 100 includes a polyvinyl alcohol (PVA) resin layer 10, a protective layer 30 provided on the visible side of the PVA resin layer 10 (visible side protective layer), and a visible side of the PVA resin layer 10. and an adhesive layer 40 disposed on the opposite side. The PVA resin layer 10 includes a first PVA resin layer 11 that functions as a polarizer, and a second PVA resin layer 12 provided on the viewing side of the first PVA resin layer 11. The second PVA resin layer 12 can also function as an adhesive layer for bonding the first PVA resin layer 11 and the viewing side protective layer 30 together. Typically, an optical functional layer may be attached via the adhesive layer 40. Representative examples of the optical functional layer include another protective layer (inner protective layer) and a retardation layer. The inner protective layer may preferably be omitted. When the optical functional layer is a retardation layer, a polarizing plate with a retardation layer is constructed. The polarizing plate with a retardation layer will be explained in Section B below. The polarizing plate 100 may be bonded to the organic EL panel via the adhesive layer 40.

In the embodiment of the present invention, the boric acid concentration on the surface of the PVA resin layer 10 (substantially the first PVA resin layer 11) on the side opposite to the viewing side is set to The difference (hereinafter sometimes referred to as boric acid concentration gradient) from the boric acid concentration on the visible side surface of the second PVA resin layer 12) is 0.3% by weight or more. More specifically, the boric acid concentration in the first PVA resin layer is higher than the boric acid concentration in the second PVA resin layer, and therefore, the boric acid concentration on the surface opposite to the visible side of the PVA resin layer A boric acid concentration gradient is formed in which the concentration is higher than the boric acid concentration on the viewing side surface. The boric acid concentration gradient is preferably 0.4% by weight or more, more preferably 0.5% by weight or more. The boric acid concentration gradient can be, for example, 27% by weight or less. The present inventors faced a new problem in that when a polarizing plate and a polarizing plate with a retardation layer were applied to an organic EL display device, the polarizing plate and the polarizing plate with a retardation layer were bleached, and they worked diligently to solve this problem. As a result of investigation, it was discovered that the cause of decolorization was ammonia (substantially ammonium ions) generated from the organic EL panel. Furthermore, the inventors discovered that the higher the boric acid concentration in the polarizer, the more suppressed the decolorization, and that the higher the boric acid concentration, the easier it is to block ammonium ions. Based on this knowledge, a second PVA resin layer is provided adjacent to the polarizer (first PVA resin layer) to form a two-layer PVA resin layer, and the visual recognition of the PVA resin layer is improved. By creating a concentration gradient such that the boric acid concentration on the side surface is at least a predetermined value lower than the boric acid concentration on the surface opposite to the viewing side, ammonium ions entering the polarizer from the organic EL panel side are blocked as much as possible. In addition, we have found that the PVA resin layer on the viewing side (the side far from the organic EL panel) can easily discharge ammonium ions, and have solved this new problem. This is because the crosslinking density of the PVA resin decreases as the distance from the organic EL panel increases, making it difficult for ammonium ions to enter the polarizer (first PVA resin layer), and even if they do, they will not be able to penetrate the polarizer (first PVA resin layer). It is presumed that this is because it becomes easier to remove. Furthermore, by making the second PVA resin layer function as an adhesive for bonding the polarizer and the protective layer, it is no longer necessary to provide the second PVA resin layer separately from the adhesive, allowing for thinner manufacturing. This is advantageous in terms of both efficiency and cost.

The boric acid concentration (at the time of coating) in the second PVA resin layer is 1% by weight or less, preferably 0.8% by weight or less, more preferably 0.5% by weight or less, and even more preferably 0. .2% by weight or less, particularly preferably substantially zero. If the concentration of the second PVA resin layer is in this range, the desired boric acid concentration gradient can be achieved between it and the polarizer (first PVA resin layer) having practical optical properties. be able to. Here, the boric acid concentration of the polarizer (first PVA resin layer) is preferably 15% by weight or more, more preferably 16% by weight or more, and even more preferably 16% to 26% by weight. be. If the boric acid concentration of the polarizer is within such a range, practical optical properties can be obtained, and the desired boric acid concentration gradient described above can be realized between the polarizer and the second PVA-based resin layer. Furthermore, it is possible to maintain ease of curl adjustment during bonding, to suppress curling during heating, and to improve appearance durability during humidification. Boric acid concentration can be determined using, for example, Fourier transform infrared spectroscopy (FT-IR). Specifically, the details are as follows. The second PVA resin layer was measured by attenuated total reflection spectroscopy (ATR) using polarized light as the measurement light using a Fourier transform infrared spectrophotometer (for example, Perkin Elmer, product name "SPECTRUM2000"). The intensity of the acid peak (665 cm ⁻¹ ) and the reference peak (2941 cm ⁻¹ ) are measured. A boric acid content index is calculated from the obtained boric acid peak intensity and reference peak intensity by the following formula, and further, a boric acid concentration can be calculated from the calculated boric acid content index by the following formula.
(Boric acid content index) = (Intensity of boric acid peak 665 cm ^-1 ) / (Intensity of reference peak 2941 cm ^-1 )
(Boric acid concentration) = (Boric acid amount index) x 6.61 + 0.47

The thickness of the second PVA resin layer is 0.03 μm to 2 μm, preferably 0.03 μm to 1 μm, more preferably 0.04 μm to 0.5 μm, even more preferably 0.04 μm to 0.05 μm. 1 μm, particularly preferably 0.05 μm to 0.1 μm. If the thickness of the second PVA-based resin layer is within this range, ammonium ions can be more easily discharged. As a result, when the polarizing plate and the polarizing plate with a retardation layer are applied to an organic EL display device, decolorization can be suppressed even better.

The polarizing plate has a polarization degree change ΔP of preferably 50% or less, more preferably 25% or less, and still more preferably 10% or less when exposed to ammonia vapor for 2 hours in a 60°C environment. . The smaller the polarization degree change ΔP is, the better, and ideally it is zero. According to the embodiment of the present invention, by employing the above configuration, it is possible to satisfactorily suppress the entry of ammonium ions into the polarizer (first PVA-based resin layer), and to remove ammonium ions from the polarizer. can be discharged well. As a result, even when the polarizing plate is exposed to ammonia, a change in the degree of polarization (substantially, a decrease in the degree of polarization) can be significantly suppressed. When such a polarizing plate (as a result, a polarizing plate with a retardation layer) is applied to an organic EL display device, decolorization can be suppressed well.

Hereinafter, the first PVA resin layer (polarizer), the second PVA resin layer, the protective layer, and the adhesive layer will be specifically explained.

A-2. First PVA-based resin layer The first PVA-based resin layer functions as a polarizer as described above. Therefore, in this specification, the first PVA-based resin layer may be referred to as a polarizer. The polarizer is typically composed of a PVA resin film containing a dichroic substance (typically iodine).

The polarizer preferably has a ratio of orthogonal absorbance A ₅₅₀ at a wavelength of 550 nm to orthogonal absorbance A ₂₁₀ at a wavelength of 210 nm (A ₅₅₀ /A ₂₁₀ ) of 1.4 or more, and a ratio of orthogonal absorbance A 470 at a wavelength of 470 nm to an orthogonal absorbance A ₂₁₀ at a wavelength of 600 nm. The ratio of the orthogonal absorbance A ₆₀₀ (A ₄₇₀ /A ₆₀₀ ) to the orthogonal absorbance A 600 is 0.7 or more, and the orthogonal b value is greater than −10. The polarizer used in the embodiment of the present invention has very large ratios (A ₅₅₀ /A ₂₁₀ ) and (A ₄₇₀ /A ₆₀₀ ) compared to ordinary thin polarizers. This is because the content ratio of iodine ions (which have absorption in the ultraviolet region around 210 nm) that do not form a complex with PVA in the polarizer is extremely small, and the content ratio of PVA-iodine complexes (which have absorption in the visible region). means that it is very large. More specifically, the polarizer has a very large content ratio of PVA-I ₅ ^-complex having absorption near 600 nm, and a large content ratio of PVA-I ₃ ^-complex having absorption near 480 nm. It has been maintained without decreasing. Here, the thickness of the polarizer means the length of the optical path, so if the thickness of the polarizer is simply made thinner, the optical path length will also become shorter and the polarization performance will also deteriorate. Since there is a limit to the amount of iodine that can be contained in a polarizer, in order to achieve both high polarization performance and a thinner polarizer, it is essential to efficiently utilize the iodine contained in the polarizer. In other words, by reducing the amount of iodine ions that absorb light in the ultraviolet range and do not contribute to polarization performance, and increasing the ratio of PVA-iodine complexes that absorb light in the visible region, it is possible to achieve both high polarization performance and a thinner polarizer. becomes possible. In other words, by increasing the ratio (A ₅₅₀ /A ₂₁₀ ), it becomes possible to achieve a thin structure and high optical properties. Furthermore, by maintaining the ratio (A ₄₇₀ /A ₆₀₀ ) at a predetermined value or higher, good polarization performance can be achieved over the entire visible light range. While the amount of iodine in a thin polarizer is limited, it was difficult to increase both the ratio (A ₅₅₀ /A ₂₁₀ ) and the ratio (A ₄₇₀ /A ₆₀₀ ) using conventional techniques, but the present invention In the polarizer used in the embodiment, both of these can be increased. The ratio (A ₅₅₀ /A ₂₁₀ ) is preferably 1.8 or more, more preferably 2.0 or more, and still more preferably 2.2 or more. The upper limit of the ratio (A ₅₅₀ /A ₂₁₀ ) can be, for example, 3.5. The ratio (A ₄₇₀ /A ₆₀₀ ) is preferably 0.75 or more, more preferably 0.80 or more, and still more preferably 0.85 or more. The upper limit of the ratio (A ₄₇₀ /A ₆₀₀ ) is, for example, 2.00, preferably 1.33. Note that the orthogonal absorbance is determined by the following formula based on the orthogonal transmittance Tc measured when determining the degree of polarization, which will be described later.
Orthogonal absorbance = log10 (100/Tc)

Further, the orthogonal b value of the polarizer is, as described above, greater than -10, preferably -7 or greater, and more preferably -5 or greater. The upper limit of the orthogonal b value is preferably +10 or less, more preferably +5 or less. According to the present invention, orthogonal b values in such a range can be realized. The orthogonal b value indicates the hue when the polarizers (polarizing plates) are arranged in an orthogonal state, and the larger the absolute value of this value, the more the orthogonal hue (black display on an image display device) appears. means. For example, if the orthogonal b value is as low as −10 or less, black display appears blue, and display performance deteriorates. That is, according to the embodiments of the present invention, it is possible to obtain a polarizer that can realize an excellent hue when displaying black. Note that the orthogonal b value can be measured using a spectrophotometer typified by LPF200.

The polarizer preferably exhibits absorption dichroism at a wavelength of 380 nm to 780 nm. The single transmittance of the polarizer is preferably 46.0% or less, more preferably 45.0% or less. On the other hand, the single transmittance is preferably 41.5% or more, more preferably 42.0% or more, and still more preferably 42.5% or more. The degree of polarization of the polarizer is preferably 99.990% or more, and preferably 99.998% or less. The polarizer used in the embodiment of the present invention can achieve both high single transmittance and high degree of polarization. The above-mentioned single transmittance is typically a Y value measured using an ultraviolet-visible spectrophotometer and subjected to visibility correction. Further, the single transmittance is a value when the refractive index of one surface of the polarizing plate is converted to 1.50 and the refractive index of the other surface is converted to 1.53. The degree of polarization is typically determined by the following formula based on parallel transmittance Tp and cross transmittance Tc measured using an ultraviolet-visible spectrophotometer and corrected for visibility.
Degree of polarization (%) = {(Tp-Tc)/(Tp+Tc)} ^1/2 ×100

The thickness of the polarizer is preferably 15 μm or less, more preferably 12 μm or less, still more preferably 10 μm or less, particularly preferably 8 μm or less. On the other hand, the thickness of the polarizer may be, for example, 1 μm or more, for example, 2 μm or more, or, for example, 3 μm or more. When the thickness of the polarizer is within such a range, curling during heating can be suppressed well, and good appearance durability during heating can be obtained.

The resin film forming the polarizer may be a single layer resin film or a laminate of two or more layers.

Specific examples of polarizers composed of single-layer resin films include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and partially saponified ethylene/vinyl acetate copolymer films. Examples include those that have been dyed with dichroic substances such as iodine and dichroic dyes and stretched, and polyene-based oriented films such as dehydrated PVA and dehydrochloric acid treated polyvinyl chloride. Preferably, a polarizer obtained by dyeing a PVA film with iodine and uniaxially stretching is used because it has excellent optical properties.

The above-mentioned staining with iodine is performed, for example, by immersing the PVA-based film in an iodine aqueous solution. The stretching ratio of the above-mentioned uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after the dyeing process or may be performed while dyeing. Alternatively, it may be dyed after being stretched. If necessary, the PVA film is subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment, etc. For example, by immersing a PVA film in water and washing it with water before dyeing, you can not only wash dirt and anti-blocking agents from the surface of the PVA film, but also swell the PVA film and prevent uneven dyeing. It can be prevented.

Specific examples of polarizers obtained using a laminate include a laminate of a resin base material and a PVA resin layer (PVA resin film) laminated on the resin base material, or a laminate of a resin base material and the resin Examples include polarizers obtained using a laminate with a PVA-based resin layer coated on a base material. A polarizer obtained using a laminate of a resin base material and a PVA-based resin layer coated on the resin base material can be obtained by, for example, applying a PVA-based resin solution to the resin base material and drying it. Forming a PVA-based resin layer thereon to obtain a laminate of a resin base material and the PVA-based resin layer; stretching and dyeing the laminate to use the PVA-based resin layer as a polarizer; obtain. In this embodiment, preferably, a polyvinyl alcohol resin layer containing a halide and a polyvinyl alcohol resin is formed on one side of the resin base material. Stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching. Furthermore, the stretching may further include stretching the laminate in air at a high temperature (for example, 95° C. or higher) before stretching in the boric acid aqueous solution, if necessary. In addition, in the present embodiment, the laminate is preferably subjected to a drying shrinkage treatment in which the laminate is heated while being conveyed in the longitudinal direction to shrink by 2% or more in the width direction. Typically, the manufacturing method of this embodiment includes subjecting the laminate to an in-air auxiliary stretching process, a dyeing process, an underwater stretching process, and a drying shrinkage process in this order. By introducing auxiliary stretching, even when PVA is applied onto a thermoplastic resin, it becomes possible to improve the crystallinity of PVA and achieve high optical properties. At the same time, by increasing the orientation of PVA in advance, it is possible to prevent problems such as deterioration of orientation and dissolution of PVA when it is immersed in water during the subsequent dyeing and stretching processes, resulting in high optical properties. becomes possible to achieve. Furthermore, when the PVA-based resin layer is immersed in a liquid, disturbance in the orientation of polyvinyl alcohol molecules and deterioration of orientation can be suppressed compared to when the PVA-based resin layer does not contain a halide. This can improve the optical properties of a polarizer obtained through a treatment process performed by immersing the laminate in a liquid, such as dyeing treatment and underwater stretching treatment. Furthermore, optical properties can be improved by shrinking the laminate in the width direction by drying shrinkage treatment. The obtained resin base material/polarizer laminate may be used as is (that is, the resin base material may be used as a protective layer for the polarizer), or the resin base material may be peeled from the resin base material/polarizer laminate. However, any appropriate protective layer may be laminated on the peeled surface depending on the purpose. Details of the method for manufacturing such a polarizer are described in, for example, Japanese Patent Application Publication No. 2012-73580 and Japanese Patent No. 6470455. The entire descriptions of these publications are incorporated herein by reference.

A-3. Second PVA-based resin layer The second PVA-based resin layer can typically be formed by applying and drying a PVA-based resin aqueous solution. The average degree of polymerization of the PVA resin contained in the aqueous solution is preferably about 100 to 5,000, more preferably 1,000 to 4,000. The average degree of saponification is preferably about 85 mol% to 100 mol%, more preferably 90 mol% to 100 mol%. If the average degree of polymerization and average degree of saponification are within these ranges, the adhesiveness with the first PVA resin layer is excellent, and as a result, the interface with the first PVA resin layer has a high resistance to ammonium ion discharge. Adverse effects can be prevented. As a result, when the polarizing plate and the polarizing plate with a retardation layer are applied to an organic EL display device, decolorization can be suppressed even better.

The PVA-based resin preferably contains an acetoacetyl group. This is because the adhesiveness between the polarizer and the protective layer is excellent and the durability can be excellent. The acetoacetyl group-containing PVA resin can be obtained, for example, by reacting a PVA resin and diketene by any method. The degree of acetoacetyl group modification of the acetoacetyl group-containing PVA resin is typically 0.1 mol% or more, preferably about 0.1 mol% to 40 mol%, more preferably 1 mol% to 20 mol%. %, particularly preferably from 2 mol % to 7 mol %. Note that the degree of acetoacetyl group modification is a value measured by NMR.

The resin concentration in the PVA resin aqueous solution is preferably 0.1% to 15% by weight, more preferably 0.5% to 10% by weight. The viscosity of the aqueous solution is preferably 1 to 50 mPa·s. The pH of the aqueous solution is preferably 2 to 6, more preferably 2.5 to 5, even more preferably 3 to 5, particularly preferably 3.5 to 4.5.

The PVA-based resin aqueous solution (as a result, the second PVA-based resin layer) may contain a metal compound colloid in one embodiment. Metal compound colloids are metal compound fine particles dispersed in a dispersion medium, and are electrostatically stabilized due to the mutual repulsion of like charges of the fine particles, and can have permanent stability. .

The average particle diameter of the fine particles forming the metal compound colloid is set to any appropriate value as long as it does not adversely affect optical properties such as transparency and polarization properties. The thickness is preferably 1 nm to 100 nm, more preferably 1 nm to 50 nm. This is because the fine particles can be uniformly dispersed in the second PVA resin layer.

Any suitable compound can be used as the metal compound. Examples include metal oxides such as alumina, silica, zirconia, and titania; metal salts such as aluminum silicate, calcium carbonate, magnesium silicate, zinc carbonate, barium carbonate, and calcium phosphate; and minerals such as celite, talc, clay, and kaolin. It will be done. A positively charged metal compound colloid is preferably used. Examples of the metal compound include alumina, titania, etc., and alumina is particularly preferred.

A-4. Protective Layer The viewing side protective layer 30 and the inner protective layer (if present) are each formed of any suitable film that can be used as a protective layer of a polarizer. Specific examples of materials that are the main components of the film include cellulose resins such as triacetylcellulose (TAC), polyesters, polyvinyl alcohols, polycarbonates, polyamides, polyimides, polyethersulfones, and polysulfones. Examples include transparent resins such as polystyrene, polynorbornene, polyolefin, (meth)acrylic, and acetate. Further, thermosetting resins or ultraviolet curable resins such as (meth)acrylic, urethane, (meth)acrylic urethane, epoxy, and silicone resins may also be mentioned. Other examples include glassy polymers such as siloxane polymers. Furthermore, the polymer film described in JP-A-2001-343529 (WO01/37007) can also be used. Materials for this film include, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in its side chain, and a thermoplastic resin having a substituted or unsubstituted phenyl group and nitrile group in its side chain. For example, a resin composition containing an alternating copolymer of isobutene and N-methylmaleimide and an acrylonitrile/styrene copolymer can be used. The polymer film may be, for example, an extrusion molded product of the resin composition.

The visible side protective layer preferably has a moisture permeability of 200 g/m ² ·24 h or more, more preferably 300 g/m ² ·24 h or more, still more preferably 330 g/m ² ·24 h or more, and particularly preferably is at least 360 g/m ² ·24 h, particularly preferably at least 400 g/m ² ·24 h. The upper limit of the moisture permeability of the viewing side protective layer may be, for example, 1000 g/m ² ·24 h. When the moisture permeability of the viewing side protective layer is within this range, the discharge of ammonium ions is further promoted, and as a result, decolorization of the polarizing plate and the polarizing plate with a retardation layer can be further suppressed. In this case, the viewing side protective layer may preferably be composed of a TAC film. Note that moisture permeability can be measured according to JIS Z 0208.

The viewing side protective layer may be subjected to surface treatments such as hard coat treatment, antireflection treatment, antisticking treatment, and antiglare treatment, as necessary. Additionally/or, the viewing-side protective layer may optionally be treated to improve visibility when viewed through polarized sunglasses (typically, imparting an (elliptical) circularly polarizing function, ultra-high (providing a phase difference) may be applied. By performing such processing, excellent visibility can be achieved even when the display screen is viewed through polarized lenses such as polarized sunglasses. Therefore, the polarizing plate and the polarizing plate with a retardation layer can be suitably applied to an image display device that can be used outdoors.

The thickness of the viewing side protective layer 30 is preferably 10 μm to 60 μm, more preferably 15 μm to 50 μm. In addition, when surface treatment is performed, the thickness of the viewing side protective layer 30 is the thickness including the thickness of the surface treatment layer.

The inner protective layer (if present) is preferably optically isotropic in one embodiment. In this specification, "optically isotropic" means that the in-plane retardation Re (550) is 0 nm to 10 nm and the thickness direction retardation Rth (550) is -10 nm to +10 nm. say. The thickness of the other protective layer is preferably 5 μm to 80 μm, more preferably 10 μm to 40 μm, even more preferably 10 μm to 30 μm. In embodiments of the invention, the inner protective layer may preferably be omitted.

A-5. Adhesive layer Typical examples of adhesives constituting the adhesive layer include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, urethane adhesives, epoxy adhesives, and Examples include polyether adhesives. By adjusting the type, number, combination, and blending ratio of monomers that form the base resin of the adhesive, as well as the amount of crosslinking agent, reaction temperature, reaction time, etc., adhesives can have desired characteristics depending on the purpose. can be prepared. The base resin of the adhesive may be used alone or in combination of two or more. From the viewpoints of transparency, processability, durability, etc., acrylic adhesives (acrylic adhesive compositions) are preferred. The acrylic pressure-sensitive adhesive composition typically contains a (meth)acrylic polymer as a main component. The (meth)acrylic polymer may be contained in the adhesive composition in an amount of, for example, 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more, based on the solid content of the adhesive composition. The (meth)acrylic polymer contains alkyl (meth)acrylate as a main component as a monomer unit. Note that (meth)acrylate refers to acrylate and/or methacrylate. The alkyl (meth)acrylate may be contained in the monomer components forming the (meth)acrylic polymer in a proportion of preferably 80% by weight or more, more preferably 90% by weight or more. Examples of the alkyl group of the alkyl (meth)acrylate include linear or branched alkyl groups having 1 to 18 carbon atoms. The average number of carbon atoms in the alkyl group is preferably 3 to 9, more preferably 3 to 6. A preferred alkyl (meth)acrylate is butyl acrylate. In addition to alkyl (meth)acrylates, the monomers (comonomers) constituting (meth)acrylic polymers include carboxyl group-containing monomers, hydroxyl group-containing monomers, amide group-containing monomers, aromatic ring-containing (meth)acrylates, Examples include ring-containing vinyl monomers. The acrylic pressure-sensitive adhesive composition may preferably contain a silane coupling agent and/or a crosslinking agent. Examples of the silane coupling agent include epoxy group-containing silane coupling agents. Examples of the crosslinking agent include isocyanate crosslinking agents and peroxide crosslinking agents. Furthermore, the acrylic adhesive composition may contain an antioxidant and/or a conductive agent. Details of the adhesive are described in, for example, JP 2006-183022, JP 2015-199942, JP 2018-053114, JP 2016-190996, and International Publication No. 2018/008712. The descriptions of these publications are incorporated herein by reference.

The adhesive has a storage modulus at 25° C., preferably 1.0×10 ⁴ Pa to 1.0×10 ⁶ Pa, more preferably 1.0×10 ⁴ Pa to 1.0×10 ⁵ Pa. It is. If the storage elastic modulus of the adhesive is within this range, peeling or floating between layers can be suppressed, and an adverse effect on the discharge of ammonium ions can be prevented.

The creep amount ΔCr of the adhesive at 70° C. may be, for example, 65 μm or less, 50 μm or less, 45 μm or less, 40 μm or less, 35 μm or less, 30 μm or less, 25 μm or less, 20 μm or less, or even 15 μm or less. The lower limit of the creep amount ΔCr is, for example, 0.5 μm. If the amount of creep is within this range, it is possible to suppress interlayer peeling or floating, and to prevent an adverse effect on the discharge of ammonium ions, as in the case of the storage modulus. The creep value can be measured, for example, by the following procedure: A load of 500 gf is applied to the adhesive attached to a stainless steel test plate at a joint surface of 20 mm long x 20 mm wide, with the test plate fixed. Add vertically downward. The creep amount (deviation amount) of the adhesive on the test plate is measured at each time point 100 seconds and 3600 seconds after the start of applying the load, and is defined as Cr ₁₀₀ and Cr ₃₆₀₀ , respectively. From the measured Cr ₁₀₀ and Cr ₃₆₀₀ , the creep amount ΔCr can be determined by the formula ΔCr=Cr ₃₆₀₀ −Cr ₁₀₀ .

The thickness of the adhesive layer is preferably 2 μm to 40 μm, more preferably 3 μm to 20 μm, and still more preferably 4 μm to 15 μm.

B. Polarizing Plate with Retardation Layer As described in Section A-1 above, in the polarizing plate according to the embodiment of the present invention, the retardation layer is bonded together via the adhesive layer 40 to constitute a polarizing plate with retardation layer. You may. Therefore, a polarizing plate with a retardation layer may also be included in the embodiments of the present invention. When the polarizing plate with a retardation layer according to the embodiment of the present invention is applied to an organic EL display device, decolorization can be significantly suppressed. The retardation layer typically has a circularly polarizing function or an elliptically polarizing function. The retardation layer typically exhibits inverse dispersion wavelength characteristics and can function as a λ/4 plate. The retardation layer may be a stretched resin film, or may be an alignment solidified layer of a liquid crystal compound (liquid crystal alignment solidified layer). The retardation layer is preferably a stretched resin film. With such a configuration, it is possible to satisfactorily suppress ammonium ions from entering the polarizer. Typical examples of resins constituting the resin film include polycarbonate resins and polyester carbonate resins.

C. Organic EL Display Device The polarizing plate described in the above section A and the polarizing plate with a retardation layer described in the above section B can be applied to an organic EL display device. Therefore, an organic EL display device including a polarizing plate or a polarizing plate with a retardation layer is also included in the embodiments of the present invention. An organic EL display device typically includes a polarizing plate or a polarizing plate with a retardation layer on its viewing side. The polarizing plate with a retardation layer is laminated so that the retardation layer is on the organic EL cell side (the polarizing plate is on the viewing side). In one embodiment, the organic EL display device has a curved shape (substantially a curved display screen) and/or is bendable or foldable. As described above, the present inventors have discovered that when a polarizing plate and a polarizing plate with a retardation layer are applied to an organic EL display device, ammonia (substantially ammonium ions) generated from the organic EL panel causes the polarizing plate and the polarizing plate to We discovered a new problem that a polarizing plate with a retardation layer is decolored, and solved this problem with the polarizing plate described in the above section A and the polarizing plate with a retardation layer described in the above section B. That is, in the organic EL display device, the effects of the polarizing plate and the polarizing plate with a retardation layer according to the embodiments of the present invention are remarkable.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples. The method for measuring each characteristic is as follows. Note that unless otherwise specified, "parts" and "%" in Examples and Comparative Examples are based on weight.
(1) Thickness The thickness of the first PVA-based resin layer was measured using an interference film thickness meter (manufactured by Otsuka Electronics Co., Ltd., product name "MCPD-3000"). The thickness of the second PVA-based resin layer was determined by cutting the polarizing plates of Examples and Comparative Examples and observing the cross section of the polarizing plate using a scanning electron microscope (JSM7100F, manufactured by JEOL Ltd.). Measured from the image.
(2) Single transmittance and degree of polarization For the polarizing plates used in Examples and Comparative Examples, single transmittance Ts, parallel transmittance Tp, The orthogonal transmittance Tc was defined as Ts, Tp, and Tc of the polarizer, respectively. These Ts, Tp, and Tc are Y values measured using a 2-degree visual field (C light source) according to JIS Z8701 and subjected to visibility correction. The degree of polarization P was determined from the obtained Tp and Tc using the following formula.
Polarization degree P (%) = {(Tp-Tc)/(Tp+Tc)} ^1/2 ×100
The orthogonal absorbance A 210 was determined from the orthogonal transmittance Tc ₂₁₀ at a measurement wavelength of 210 nm, and the orthogonal absorbance A ₅₅₀ was determined from the orthogonal transmittance Tc ₅₅₀ at a measurement wavelength of 550 _nm using "U4100" manufactured by Hitachi High Technologies. In addition, the orthogonal absorbance A 470 is calculated from the orthogonal transmittance Tc ₄₇₀ at the measurement wavelength of 470 nm, and the orthogonal absorbance A ₆₀₀ is calculated from the orthogonal transmittance Tc ₆₀₀ at the measurement _wavelength 600 nm, respectively, manufactured by JASCO Corporation, product name "V-7100". It was found using
(3) Moisture permeability Measured according to JIS Z 0208. Specifically, the protective layer (the film constituting it) used in the Examples and Comparative Examples was cut into a 10 cm diameter circle and used as a measurement sample. The moisture permeability of this measurement sample was measured using "MOCON" manufactured by Hitachi, Ltd. under test conditions of 40° C. and 92% RH.
(4) Orthogonal b value The polarizing plates used in the examples and comparative examples were measured using an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, product name "V7100"), and the hue in the crossed nicol state was determined. . This indicates that the lower the orthogonal b value (negative value and larger absolute value) of the polarizing plate, the more blue the hue is rather than neutral.
(5) Boric acid concentration For the polarizing plates obtained in Examples and Comparative Examples, polarization was measured using a Fourier transform infrared spectrophotometer (FT-IR) (manufactured by Perkin Elmer, trade name "SPECTRUM2000"). The intensity of the boric acid peak (665 cm ⁻¹ ) and the reference peak (2941 cm ⁻¹ ) were measured by attenuated total reflection spectroscopy (ATR) using light. A boric acid content index was calculated from the obtained boric acid peak intensity and reference peak intensity using the following formula, and further, a boric acid concentration was determined from the calculated boric acid content index using the following formula.
(Boric acid content index) = (Intensity of boric acid peak 665 cm ^-1 ) / (Intensity of reference peak 2941 cm ^-1 )
(Boric acid concentration) = (Boric acid amount index) x 6.61 + 0.47
(6) Ammonia decolorization test 1.5 ml of a 10% ammonia aqueous solution was placed in a glass bottle (cylindrical with a diameter of 30 mm and a depth of 50 mm). At this time, the distance from the liquid level of the ammonia aqueous solution to the mouth (upper end) of the glass bottle was about 30 mm. The polarizing plates obtained in Examples and Comparative Examples were cut into a size of 30 mm x 30 mm and used as measurement data. The measurement material was adhered to the rim of the glass bottle via an adhesive layer so that the mouth of the glass bottle was completely covered with the measurement material and steam did not leak from the gap. The glass bottle covered with the measurement material was heated at 60° C. for 2 hours. The absolute value of the change in the degree of polarization |ΔP| was calculated from the following formula, assuming that the degree of polarization before heating of the polarizing plate (substantially, a polarizer) is P ₀ and the degree of polarization after heating is P ₂₀ . The smaller |ΔP| means that decolorization by ammonia is suppressed.
|ΔP|=|P ₂₀ -P ₀ |
Based on the obtained ΔP, evaluation was made according to the following criteria.
A: |ΔP| is 10% or less B: |ΔP| is greater than 10% and less than 25% C: |ΔP| is greater than 25% and less than 50% D: |ΔP| is greater than 50% and less than 75% E: |ΔP| is greater than 75%

[Example 1]
1. Preparation of polarizer A long, amorphous isophthalic copolymerized polyethylene terephthalate film (thickness: 100 μm) with a Tg of approximately 75°C was used as the thermoplastic resin base material, and one side of the resin base material was subjected to corona treatment. was applied.
100 parts by weight of a PVA resin prepared by mixing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd., trade name "Gosefaimer") at a ratio of 9:1. to which 13 parts by weight of potassium iodide was added was dissolved in water to prepare a PVA aqueous solution (coating solution).
The PVA aqueous solution was applied to the corona-treated surface of the resin base material and dried at 60° C. to form a PVA-based resin layer with a thickness of 13 μm, thereby producing a laminate.
The obtained laminate was uniaxially stretched 2.4 times in the vertical direction (longitudinal direction) in an oven at 130° C. (in-air auxiliary stretching treatment).
Next, the laminate was immersed for 30 seconds in an insolubilization bath (boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40° C. (insolubilization treatment).
Next, the final polarizer was added to a dyeing bath (an aqueous iodine solution obtained by blending iodine and potassium iodide at a weight ratio of 1:7 to 100 parts by weight of water) at a liquid temperature of 30°C. It was immersed for 60 seconds while adjusting the concentration so that the single transmittance (Ts) was 43.0% (staining treatment).
Next, it was immersed for 30 seconds in a crosslinking bath (an aqueous boric acid solution obtained by blending 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 40°C. (Crosslinking treatment).
Thereafter, while immersing the laminate in a boric acid aqueous solution (boric acid concentration: 4% by weight, potassium iodide concentration: 5% by weight) at a liquid temperature of 70°C, the laminate was completely rolled in the longitudinal direction (longitudinal direction) between rolls having different circumferential speeds. Uniaxial stretching was performed so that the stretching ratio was 5.5 times (underwater stretching treatment).
Thereafter, the laminate was immersed in a cleaning bath (an aqueous solution obtained by blending 3 parts by weight of potassium iodide with 100 parts by weight of water) at a liquid temperature of 20° C. (cleaning treatment).
Thereafter, while drying in an oven kept at about 90°C, it was brought into contact with a SUS heating roll whose surface temperature was kept at about 75°C (drying shrinkage treatment).
In this way, a polarizer was formed on the resin base material, and a laminate having a structure of resin base material/polarizer (first PVA-based resin layer) was obtained. The thickness of the polarizer (first PVA resin layer) was 5 μm, and the single transmittance was 43.0%.

2. Preparation of Polarizing Plate A second PVA resin layer was formed on the surface of the polarizer (first PVA resin layer) of the laminate obtained above, and a protective layer was laminated thereon. Specifically, the details are as follows. Acetoacetyl-modified PVA (polymerization degree 1200, acetoacetyl modification degree 4.6%, saponification degree 99.0 mol% or more, solid content concentration 4%, manufactured by Mitsubishi Chemical Corporation, product name "Gosenex Z-200")6. A water-based resin composition was obtained by mixing 25 parts of an aqueous solution containing positively charged alumina colloid (average particle size 15 nm) at a solid content concentration of 3.2%, and 18.98 parts of pure water. The resin composition was coated on the surface of the first PVA resin layer so that the thickness after drying was 0.09 μm, and the HC-TAC film was laminated using a roll machine. By drying, a second PVA-based resin layer was formed and the polarizer and protective layer were bonded together. The HC-TAC film is a film in which a hard coat (HC) layer (7 μm thick) is formed on a triacetyl cellulose (TAC) film (25 μm thick), and the TAC film is on the first PVA resin layer side. I glued it together so that it looked like this. The moisture permeability of the HC-TAC film was 427 g/m ² ·24 h. Next, the resin base material is peeled off, an acrylic adhesive (thickness 20 μm) is placed on the peeled surface, and the visible side protective layer (HC-TAC film)/second PVA resin layer/first PVA resin A polarizing plate having a structure of layer (polarizer)/adhesive layer (acrylic adhesive) was obtained. The boric acid concentration on the surface opposite to the visible side of the first PVA resin layer was 17.5% by weight, and the boric acid concentration on the visible side surface of the second PVA resin layer was 17.0% by weight. Ta. Furthermore, the polarizer in the obtained polarizing plate had an A ₅₅₀ /A ₂₁₀ of 2.59, an A ₄₇₀ /A ₆₀₀ of 0.96, and an orthogonal b value of -1.6. The obtained polarizing plate was subjected to the evaluation described in (6) above. The results are shown in Table 1.
Note that the acrylic adhesive was prepared as follows. 91 parts of butyl acrylate, 6 parts of acryloylmorpholine, 2.7 parts of acrylic acid, and 0.3 parts of 4-hydroxybutyl acrylate were placed in a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser. A monomer mixture was charged. Further, to 100 parts of this monomer mixture, 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator was charged together with 100 parts of ethyl acetate, and nitrogen gas was introduced while stirring gently to make nitrogen. After the substitution, a polymerization reaction was carried out for 8 hours while maintaining the liquid temperature in the flask at around 55° C. to prepare a solution of an acrylic polymer having a weight average molecular weight (Mw) of 2.7 million and Mw/Mn=3.8. Per 100 parts of the solid content of the above acrylic polymer solution, 0.1 part of trimethylolpropane/tolylene diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Coronate L"), peroxide crosslinking agent (manufactured by NOF Corporation) , trade name "Niper BMT") and 0.2 parts of an epoxy group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") to obtain an acrylic adhesive. Ta.

[Example 2]
A polarizing plate was obtained in the same manner as in Example 1, except that the conditions of the crosslinking treatment when producing the polarizer (first PVA-based resin layer) were changed and the boric acid concentration of the polarizer was changed. The boric acid concentration on the surface opposite to the visible side of the first PVA resin layer was 21.8% by weight, and the boric acid concentration on the visible side surface of the second PVA resin layer was 19.7% by weight. Ta. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[Example 3]
The thickness of the second PVA resin layer was set to 0.07 μm, and the conditions of the crosslinking treatment when producing the polarizer (first PVA resin layer) were changed to increase the boric acid concentration of the polarizer. A polarizing plate was obtained in the same manner as in Example 1 except for the following changes. The boric acid concentration on the surface opposite to the visible side of the first PVA resin layer was 21.8% by weight, and the boric acid concentration on the visible side surface of the second PVA resin layer was 20.3% by weight. Ta. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[Example 4]
The resin base material/polarized light was prepared in the same manner as in Example 1, except that the optical properties of the polarizer were changed by changing the conditions of the crosslinking treatment and stretching treatment when producing the polarizer (first PVA-based resin layer). A laminate having the same structure was obtained. The thickness of the polarizer was 5 μm, the single transmittance was 43.0%, A ₅₅₀ /A ₂₁₀ was 1.37, A ₄₇₀ /A ₆₀₀ was 0.90, and the orthogonal b value was −2.62. A polarizing plate was obtained by following the same procedure as in Example 1. The boric acid concentration on the surface opposite to the visible side of the first PVA resin layer was 14.3% by weight, and the boric acid concentration on the visible side surface of the second PVA resin layer was 13.9% by weight. Ta. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[Example 5]
A long roll of polyvinyl alcohol (PVA) resin film (manufactured by Kuraray, product name "PE3000") with a thickness of 30 μm was simultaneously uniaxially stretched in the longitudinal direction to a length of 5.9 times using a roll stretching machine. A polarizer (first PVA resin layer) having a thickness of 12 μm was produced by performing swelling, dyeing, crosslinking, washing, and finally drying.
Specifically, in the swelling treatment, the film was stretched 2.2 times while being treated with pure water at 20°C. Next, the dyeing process was carried out in an aqueous solution at 30 °C in which the weight ratio of iodine and potassium iodide was 1:7, and the iodine concentration was adjusted so that the single transmittance of the obtained polarizer was 43.0%. However, it was stretched 1.4 times. Furthermore, a two-stage crosslinking process was adopted for the crosslinking process, and the first crosslinking process was performed in an aqueous solution containing boric acid and potassium iodide at 40°C, and was stretched to 1.2 times. The boric acid content of the aqueous solution for the first stage crosslinking treatment was 5.0% by weight, and the potassium iodide content was 3.0% by weight. In the second stage of crosslinking treatment, the film was stretched to 1.6 times while being treated in an aqueous solution containing boric acid and potassium iodide at 65°C. The boric acid content of the aqueous solution for the second stage crosslinking treatment was 4.3% by weight, and the potassium iodide content was 5.0% by weight. Further, the cleaning treatment was performed using a potassium iodide aqueous solution at 20°C. The potassium iodide content of the aqueous solution for cleaning treatment was 2.6% by weight. Finally, the drying process was performed at 70° C. for 5 minutes to obtain a polarizer (first PVA resin layer).
A polarizing plate was obtained in the same manner as in Example 1 except that this polarizer (first PVA-based resin layer) was used. Here, the boric acid concentration on the surface of the first PVA-based resin layer opposite to the visible side is 24% by weight, and the boric acid concentration on the visible-side surface of the second PVA-based resin layer is 21.6% by weight. there were. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[Comparative example 1]
A laminate having a resin base material/polarizer configuration was obtained in the same manner as in Example 1. The same HC-TAC film as in Example 1 was attached to the surface of the polarizer of the laminate via an ultraviolet curable adhesive (thickness: 1 μm). That is, the second PVA-based resin layer was not formed. In this way, a polarizing plate having the structure of viewing side protective layer (HC-TAC film)/adhesive/polarizer/adhesive layer (acrylic adhesive) was obtained. The boric acid concentration on the surface opposite to the viewing side of the PVA resin layer (polarizer only) was 13.6% by weight, and the boric acid concentration on the viewing side surface was 15.4% by weight. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[Comparative example 2]
A polarizing plate was obtained in the same manner as in Comparative Example 1, except that the conditions of the crosslinking treatment when producing the polarizer were changed and the boric acid concentration of the polarizer was changed. The boric acid concentration on the surface opposite to the viewing side of the PVA resin layer (polarizer only) was 16.6% by weight, and the boric acid concentration on the viewing side surface was 18.6% by weight. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[Comparative example 3]
A polarizing plate was obtained in the same manner as in Example 1 except that an HC-COP film was used as the viewing side protective layer. The HC-COP film is a film in which a hard coat (HC) layer (thickness: 2 μm) is formed on a COP film (thickness: 25 μm), and its moisture permeability is 35 g/m ² ·24 h. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[evaluation]
As is clear from Table 1, according to the examples of the present invention, it is possible to obtain a polarizing plate whose degree of polarization hardly changes (that is, does not bleach) even when exposed to ammonia. That is, according to the examples of the present invention, it is possible to realize a polarizing plate and a polarizing plate with a retardation layer in which decolorization is suppressed when applied to an organic EL display device. On the other hand, the polarizing function of the polarizing plate of the comparative example is significantly reduced.

The polarizing plate of the present invention is suitably used for organic EL display devices, and the polarizing plate with a retardation layer is suitably used as an antireflection circularly polarizing plate for organic EL display devices.

10 PVA resin layer 11 First PVA resin layer (polarizer)
12 Second PVA resin layer 30 Protective layer 40 Adhesive layer 100 Polarizing plate

Claims (7)

a polyvinyl alcohol resin layer, a protective layer provided on the visible side of the polyvinyl alcohol resin layer, and a protective layer disposed adjacent to the polyvinyl alcohol resin layer on the opposite side of the visible side of the polyvinyl alcohol resin layer. an adhesive layer;
The polyvinyl alcohol resin layer includes a first polyvinyl alcohol resin layer that functions as a polarizer, and a second polyvinyl alcohol resin layer provided on the viewing side of the first polyvinyl alcohol resin layer. including,
The thickness of the second polyvinyl alcohol resin layer is 0.03 μm to 2 μm,
The boric acid concentration on the surface opposite to the visible side of the polyvinyl alcohol resin layer is higher than the boric acid concentration on the visible side surface, and the difference therebetween is 0.3% by weight or more,
The moisture permeability of the protective layer on the visible side is 200 g/m ² 24 h or more ,
The amount of creep at 70°C of the adhesive constituting the adhesive layer is 65 μm or less,
The absolute value of the change in polarization degree |ΔP| when exposed to ammonia vapor for 2 hours in a 60°C environment is 50% or less ,
Polarizer. The polarizing plate according to claim 1, wherein the first polyvinyl alcohol resin layer has a boric acid concentration of 14% by weight or more. The first polyvinyl alcohol resin layer is
Single transmittance is 42.5% or more,
The ratio of the orthogonal absorbance A ₅₅₀ at a wavelength of 550 nm to the orthogonal absorbance A ₂₁₀ at a wavelength of 210 nm (A ₅₅₀ /A ₂₁₀ ) is 1.4 or more,
The ratio of the orthogonal absorbance A ₄₇₀ at a wavelength of 470 nm and the orthogonal absorbance A ₆₀₀ at a wavelength of 600 nm (A ₄₇₀ /A ₆₀₀ ) is 0.7 or more, and
the orthogonal b value is greater than -10,
The polarizing plate according to claim 1 or 2. 4. The polarizing plate according to claim 1, wherein the first polyvinyl alcohol resin layer has an iodine concentration of 2% to 10% by weight. The polarizing plate according to any one of claims 1 to 4, wherein the adhesive constituting the adhesive layer contains acrylic acid and acryloylmorpholine as monomer components . A polarizing plate with a retardation layer, comprising the polarizing plate according to claim 1 and a retardation layer. An organic electroluminescent display device comprising the polarizing plate according to any one of claims 1 to 5 or the polarizing plate with a retardation layer according to claim 6.

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