Polarizing plate and picture display unit

Abstract

To provide a polarizing plate with a smaller deviation at a through hole part even under a high temperature environment, the polarizing plate capable of significantly suppressing air bubbles at the through hole part when a through hole is filled by an adhesive agent for laminating cover glass in a picture display unit.SOLUTION: A polarizing plate includes a polarizer, a protective layer arranged at least on one side of the polarizer, and an adhesive layer, and further includes a through hole formed therein. The polarizer has a thickness of 15 μm or less and |b1-b2| of 45 mm or less. b1 is a distance from a center of the through hole to one end of the polarizing plate in an absorption axis direction of the polarizer, and b2 is a distance from the center of the through hole to the other end of the polarizing plate in the absorption axis direction of the polarizer.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present invention relates to a polarizing plate and an image display device. More specifically, the present invention relates to a polarizing plate having a pressure-sensitive adhesive layer and having through holes formed therein, and an image display device including such a polarizing plate. [Background technology]

[0002] Polarizing plates are widely used in image display devices such as mobile phones and notebook personal computers to realize image display and / or improve the performance of the image display. In recent years, polarizing plates are also desired to be used in image display devices equipped with cameras, smart watches, and instrument panels of automobiles, and through holes may be formed in the polarizing plate. However, polarizing plates having through holes have a problem in that the polarizing plate may shift (effectively, the pressure-sensitive adhesive layer may shift) at the through hole portion in a high-temperature environment.

[0003] Incidentally, in order to impart surface hardness and impact resistance to the image display device, a cover glass may be laminated on the outermost surface of the image display device. When a cover glass is laminated on an image display device including a polarizing plate having a through hole, the through hole is typically filled with an adhesive for laminating the cover glass. However, in the image display device in which the through hole is filled with the adhesive, air bubbles may be generated in the filled portion (through hole portion) due to a heat treatment or the like in the manufacturing process. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 047510 [Patent Document 2] JP 2016-094569 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made to solve the above-mentioned problems in the conventional art, and its main object is to provide a polarizing plate in which there is little misalignment in the through-hole portion even in a high-temperature environment, and in which air bubbles in the through-hole portion can be significantly suppressed when the through-hole is filled with an adhesive for laminating a cover glass in an image display device. [Means for solving the problem]

[0006] The polarizing plate of the present invention has a polarizer, a protective layer disposed on at least one side of the polarizer, and a pressure-sensitive adhesive layer, has a through hole formed therein, the polarizer has a thickness of 15 μm or less, and |b1-b2| is 45 mm or less, where b1 is the distance from the center of the through hole to one end of the polarizing plate in the absorption axis direction of the polarizer, and b2 is the distance from the center of the through hole to the other end of the polarizing plate in the absorption axis direction of the polarizer. In one embodiment, the polarizing plate has a rectangular shape, the absorption axis direction of the polarizer is 135° clockwise from the long side direction as viewed from the viewing side, and the through hole is formed in the right corner. In another embodiment, the polarizing plate has a rectangular shape, the absorption axis direction of the polarizer is 45° clockwise from the long side direction as viewed from the viewing side, and the through hole is formed in the left corner. In yet another embodiment, the polarizing plate has a rectangular shape, the absorption axis direction of the polarizer is the short side direction, and the through hole is formed at the end of the long side direction and the center of the short side direction when viewed in plan. In one embodiment, the polarizer has a thickness of 8 μm or less. In one embodiment, the pressure-sensitive adhesive layer has a creep value of 140 μm / hr or less. According to another aspect of the present invention, there is provided an image display device, comprising an image display cell and the above polarizing plate, the polarizing plate being attached to the image display cell via the pressure-sensitive adhesive layer. Effect of the Invention

[0007] According to an embodiment of the present invention, it is possible to realize a polarizing plate having a through hole, which exhibits small misalignment in the through hole portion even in a high temperature environment, and in which air bubbles in the through hole portion can be significantly suppressed when the through hole is filled with an adhesive for laminating a cover glass in an image display device. [Brief description of the drawings]

[0008] [Figure 1A] FIG. 2 is a schematic plan view illustrating the positions at which through-holes are formed in a polarizing plate according to one embodiment of the present invention. [Figure 1B] 11 is a schematic plan view illustrating the positions at which through holes are formed in a polarizing plate according to another embodiment of the present invention. FIG. [Figure 1C] FIG. 13 is a schematic plan view illustrating the positions at which through holes are formed in a polarizing plate according to still another embodiment of the present invention. [Diagram 2] 3 is a schematic cross-sectional view of a through-hole portion of a polarizing plate according to an embodiment of the present invention. FIG. [Diagram 3] 5 is an enlarged cross-sectional view of a main portion illustrating a misalignment at a through-hole portion in a polarizing plate according to an embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, specific embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. Note that the drawings are schematic for ease of viewing, and the ratios of length, width, thickness, and the like, as well as angles, etc. in the drawings are different from the actual ones.

[0010] A. Overall structure of polarizing plate FIG. 1A is a schematic plan view illustrating the position of a through hole in a polarizing plate according to one embodiment of the present invention; FIG. 1B is a schematic plan view illustrating the position of a through hole in a polarizing plate according to another embodiment of the present invention; FIG. 1C is a schematic plan view illustrating the position of a through hole in a polarizing plate according to yet another embodiment of the present invention; and FIG. 2 is a schematic cross-sectional view of a through hole portion of a polarizing plate. A polarizing plate according to an embodiment of the present invention (polarizing plates 100, 101, and 102 in the illustrated example) has a polarizer 11, a protective layer (hereinafter sometimes referred to as an outer protective layer) 12 arranged on one side of the polarizer 11, a protective layer (hereinafter sometimes referred to as an inner protective layer) 13 arranged on the other side of the polarizer 11, and an adhesive layer 20. The adhesive layer 20 is used to attach the polarizing plate 100 to an image display cell. Depending on the purpose and the desired configuration, either the outer protective layer 12 or the inner protective layer 13 may be omitted.

[0011] The polarizing plate has a through hole 30 formed therein. By forming the through hole, for example, when the image display device has a built-in camera, it is possible to prevent adverse effects on the camera performance. The through hole can be formed by various methods, such as laser processing, cutting processing with an end mill, and punching processing with a Thomson blade or a Pinnacle (registered trademark) blade. The polarizing plate typically has a rectangular shape. In this specification, the term "rectangular shape" includes a shape including an irregularly processed portion such as an R shape with each apex chamfered as shown in Figures 1A to 1C. Although not shown, a plurality of through holes may be provided. In addition, any appropriate shape may be adopted as the planar shape of the through hole depending on the purpose. Specific examples of the planar shape include a circle, an ellipse, a square, a rectangle, and a combination of these (for example, a rectangle with an arc-shaped end) as shown in the illustrated example. Furthermore, an irregularly processed portion (for example, a U-shaped notch or a V-shaped notch) may be provided together with the through hole. The present inventors have found a new problem that, when a through hole is formed in a polarizing plate, the polarizing plate may shift (essentially, the adhesive layer may shift: hereinafter, this may be referred to as glue shift) at the through hole portion in a high temperature environment, and as a result, light leakage may occur at the through hole portion. The present inventors have solved this problem by adopting a specific configuration (described later) of an embodiment of the present invention. That is, the present invention solves a new problem that has not been known until now, and the effect obtained by this is unexpectedly excellent. Furthermore, the present inventors have found that by adopting a specific configuration (described later) of an embodiment of the present invention, it is possible to significantly suppress bubbles called so-called delay bubbles. The details of the delay bubbles are as follows. In order to impart surface hardness and impact resistance to the image display device, a cover glass may be laminated on the outermost surface of the image display device. When a cover glass is laminated on an image display device including a polarizing plate having a through hole, the through hole is typically filled with an adhesive for laminating the cover glass. Such filling is typically performed by laminating a laminate of a cover glass and an adhesive sheet to the polarizing plate by vacuum lamination.While there are often no recognizable bubbles in the filled portion immediately after vacuum lamination, bubbles may occur during a subsequent heat durability test of the image display device. Such bubbles may typically occur when shrinkage stress of the polarizing plate is applied to the filled portion. Such bubbles are called delay bubbles. Delay bubbles are not minute, but large, occupying a certain percentage or more of the planar area of ​​the through-hole, and are unacceptable from the viewpoint of both appearance and camera performance of the camera unit provided at a position corresponding to the through-hole. Therefore, by suppressing delay bubbles, the commercial value of the image display device can be significantly improved.

[0012] In an embodiment of the present invention, the thickness of the polarizer is 15 μm or less, preferably 10 μm or less, more preferably 8 μm or less, even more preferably 7 μm or less, particularly preferably 6 μm or less, and particularly preferably 5 μm or less. The thickness of the polarizer may be, for example, 1 μm or more, or, for example, 2 μm or more. By setting the thickness of the polarizer in such a range, the thermal shrinkage of the polarizer itself can be suppressed. As a result, the deformation of the pressure-sensitive adhesive layer (resulting in adhesive slippage) that may follow the thermal shrinkage of the polarizer can be suppressed.

[0013] Furthermore, in an embodiment of the present invention, |b1-b2| is 45 mm or less, preferably 30 mm or less, more preferably 20 mm or less, even more preferably 10 mm or less, and particularly preferably 5 mm or less. |b1-b2| is preferably as small as possible, and is most preferably 0 (zero). If |b1-b2| is in this range, glue slippage at the through-hole portion in a high-temperature environment can be reduced, and delayables can be suppressed. On the other hand, |a1-a2| does not substantially contribute to suppressing glue slippage or delayables at the through-hole portion. In other words, even if |a1-a2| is changed, glue slippage and delayables are not suppressed. Here, b1 is the distance from the center of the through hole to one end of the polarizing plate in the absorption axis direction of the polarizer, b2 is the distance from the center of the through hole to the other end of the polarizing plate in the absorption axis direction of the polarizer, a1 is the distance from the center of the through hole to one end of the polarizing plate in the direction perpendicular to the absorption axis direction of the polarizer, and a2 is the distance from the center of the through hole to the other end of the polarizing plate in the direction perpendicular to the absorption axis direction of the polarizer. In other words, by optimizing the direction of the absorption axis of the polarizer with respect to the position of the through hole, both glue slippage and delayability can be suppressed.

[0014] The relationship between a1, a2, b1, and b2 and the formation position of the through-hole will be specifically described with reference to FIG. 1A to FIG. 1C. FIG. 1A shows a configuration in which the polarizing plate is rectangular and the absorption axis direction A of the polarizer is 135° clockwise with respect to the long side direction when viewed from the viewing side (opposite to the adhesive layer) of the image display device. In this configuration, by optimizing |b1-b2|, the through-hole 30 can be suppressed both by forming it at any position on a straight line (on the straight line showing the distances a1 and a2 in FIG. 1A) extending from the upper right corner in a direction perpendicular to the absorption axis direction A when the polarizing plate is viewed in plan from the viewing side. On the other hand, by adjusting |a1-a2| to minimize the influence on the image display, the through-hole 30 can be preferably formed at the upper right corner. FIG. 1B shows a configuration in which the polarizing plate is rectangular and the absorption axis direction A of the polarizer is 45° clockwise with respect to the long side direction when viewed from the viewing side of the image display device. In this embodiment, both the glue slippage and the delayables can be suppressed by optimizing |b1-b2|, and the influence on the image display can be minimized by adjusting |a1-a2|. As a result, in this embodiment, the through hole 30 can be preferably formed in the upper left corner. FIG. 1C shows an embodiment in which the polarizing plate is rectangular and the absorption axis direction A of the polarizer is in the short side direction (perpendicular to the long side direction). In this embodiment, both the glue slippage and the delayables can be suppressed by optimizing |b1-b2|, and the influence on the image display can be minimized by adjusting |a1-a2|. As a result, in this embodiment, the through hole 30 can be preferably formed at the end of the long side direction and the center of the short side direction. As is clear from the above, according to the embodiment of the present invention, regardless of the planar shape of the polarizing plate (for example, even if it has a special planar shape), the relationship between the position of the through hole and the absorption axis direction at which the glue slippage and the delayables can be suppressed can be determined by optimizing |b1-b2|. Furthermore, the influence of the through hole on the image display can be minimized by adjusting |a1-a2|.

[0015] In one embodiment, as shown in FIG. 3, the polarizing plate 100 is attached to a glass plate (corresponding to a substrate of an image display cell) 120 via an adhesive layer 20, and after a heating test at 85° C. for 120 hours, the displacement (glue displacement) D at the through-hole 30 portion is preferably 150 μm or less, more preferably 120 μm or less, even more preferably 100 μm or less, particularly preferably 80 μm or less, and particularly preferably 50 μm or less. The smaller the displacement D, the more preferable it is, and the lower limit of the glue displacement D may be, for example, 10 μm or, for example, 20 μm. The glue displacement D refers to the maximum portion of the polarizing plate that is far from the through-hole portion when viewed in cross section. The reference for the through-hole portion may typically be the lower end of the adhesive layer. That is, when the polarizing plate shifts (to the right in the illustrated example) mainly due to the shrinkage of the polarizer 11, the adhesive layer 20 remains on the adhered glass plate 120, and the shift is recognized in the through-hole portion. As shown in FIG. 3, the polarizing plate typically shifts away from the through-hole portion (right side of FIG. 3), and the opposing portion shifts so as to protrude into the through-hole (left side of FIG. 3). As described above, according to the embodiment of the present invention, it is possible to solve the newly discovered problem of adhesive slippage in the through-hole portion in a high-temperature environment, and specifically, it is possible to set the amount of adhesive slippage D after a predetermined heating test to the range described above.

[0016] In one embodiment, the polarizing plate may have an adhesive void formed in the through-hole 30 portion such that the end face of the adhesive layer 20 is located inward in the plane direction from the end face of the polarizing plate (substantially, the polarizer 11 or the inner protective layer 13, if present). The size of the adhesive void is preferably 300 μm or less, more preferably 200 μm or less, even more preferably 150 μm or less, particularly preferably 100 μm or less, and particularly preferably 80 μm or less. The lower limit of the size of the adhesive void may be, for example, 10 μm. In this specification, the "size of the adhesive void" refers to the maximum length from the end face of the polarizing plate (substantially, the polarizer 11 or the inner protective layer 13, if present) to the end face of the adhesive layer 20.

[0017] In an embodiment of the present invention, the dimensional shrinkage of the polarizing plate after the heating test is preferably 1.0% or less, more preferably 0.6% or less, and even more preferably 0.3% or less. The smaller the dimensional shrinkage, the more preferable it is, and the lower limit of the dimensional shrinkage may be, for example, 0.01%. The dimensional shrinkage is calculated by the following formula. The dimensional shrinkage is the dimensional shrinkage of the entire polarizing plate attached to the glass plate, and when the polarizing plate further has an optical functional layer (for example, a retardation layer, a reflective polarizer) as described later, it means the dimensional shrinkage of the entire polarizing plate including the optical functional layer. The "dimension" in the following formula is the dimension in the absorption axis direction of the polarizing plate (substantially, the polarizer). Dimensional shrinkage rate (%) = {(dimension before heating test - dimension after heating test) / dimension before heating test} x 100

[0018] The diameter R of the through hole 30 is preferably 10 mm or less, more preferably 8 mm or less, and even more preferably 5 mm or less. The lower limit of the diameter of the through hole is, for example, 1.5 mm, and can be, for example, 2 mm. The ratio D / R of the glue shift amount D to the diameter R of the through hole is preferably 15% or less, more preferably 10% or less, even more preferably 6% or less, and particularly preferably 5% or less. On the other hand, the lower limit of D / R is preferably as small as possible. According to the embodiment of the present invention, since the glue shift amount D is very small as described above, even if the diameter of the through hole is reduced, D / R can be in such a range. Therefore, even if the diameter of the through hole is reduced, adverse effects on the camera performance can be substantially prevented. As a result, the polarizing plate according to the embodiment of the present invention can be applied to an image display device in which only the camera unit is a non-display area and / or a bezel-less image display device.

[0019] The polarizing plate according to the embodiment of the present invention may be used as a viewer-side polarizing plate or a rear-side polarizing plate. Furthermore, the polarizing plate according to the embodiment of the present invention may further have any suitable optical functional layer depending on the purpose. Examples of the optical functional layer include a retardation layer, a conductive layer for a touch panel, and a reflective polarizer.

[0020] In one embodiment, a retardation layer may be provided between the inner protective layer 13 and the pressure-sensitive adhesive layer 20. The retardation layer may be composed of a single layer or may have a laminated structure. When the retardation layer is composed of a single layer, the retardation layer may typically function as a λ / 4 plate. In this case, the in-plane retardation Re(550) of the retardation layer is preferably 100 nm to 200 nm, more preferably 120 nm to 170 nm, and further preferably 130 nm to 150 nm. The angle between the absorption axis of the polarizer and the slow axis of the retardation layer is preferably 40° to 50°, more preferably 42° to 48°, and further preferably 44° to 46°. The retardation layer preferably exhibits an inverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light. In this case, Re(450) / Re(550) of the retardation layer is preferably 0.8 or more and less than 1, and more preferably 0.8 or more and 0.95 or less. The retardation layer may be a stretched film of a resin film or an alignment-solidified layer of a liquid crystal compound. When the retardation layer is composed of a resin film, the retardation layer may also serve as an inner protective layer. Retardation layers composed of stretched films of a resin film are described, for example, in JP 2017-54093 A and JP 2018-60014 A. Specific examples of liquid crystal compounds and details of a method for forming an alignment-solidified layer are described, for example, in JP 2006-163343 A. The descriptions in these publications are incorporated herein by reference. In this specification, "Re(λ)" is an in-plane retardation measured with light having a wavelength of λ nm at 23° C. For example, "Re(550)" is an in-plane retardation measured with light having a wavelength of 550 nm at 23° C. Re(λ) is calculated by the formula: Re(λ)=(nx-ny)×d, where d(nm) is the thickness of the layer (film). nx is the refractive index in the direction in which the in-plane refractive index is maximum (ie, the slow axis direction), and ny is the refractive index in the in-plane direction perpendicular to the slow axis (ie, the fast axis direction).

[0021] When the retardation layer has a laminated structure, the retardation layer typically has an H layer and a Q layer in this order from the polarizing plate side. The H layer typically functions as a λ / 2 plate, and the Q layer typically functions as a λ / 4 plate. The Re(550) of the H layer is preferably 200 nm to 300 nm, more preferably 230 nm to 290 nm, and further preferably 260 nm to 280 nm. The angle between the absorption axis of the polarizer and the slow axis of the H layer is preferably 10° to 20°, more preferably 12° to 18°, and further preferably 14° to 16°. The Re(550) of the Q layer is preferably 100 nm to 200 nm, more preferably 120 nm to 170 nm, and further preferably 130 nm to 150 nm. The angle between the absorption axis of the polarizer and the slow axis of the Q layer is preferably 70° to 80°, more preferably 72° to 78°, and further preferably 74° to 76°. The arrangement order of the H layer and the Q layer may be reversed, and the angle between the slow axis of the H layer and the absorption axis of the polarizer and the angle between the slow axis of the Q layer and the absorption axis of the polarizer may be reversed. Each of the H layer and the Q layer may be a stretched resin film or an oriented and solidified layer of a liquid crystal compound.

[0022] In one embodiment, a conductive layer for a touch panel may be provided on the side of the inner protective layer 13 (or the retardation layer, if present) opposite the polarizer. With such a configuration, the polarizing plate may be applied to a so-called inner touch panel type input display device in which a touch sensor is incorporated between an image display cell and the polarizing plate. The polarizing plate of this embodiment is typically a viewing side polarizing plate.

[0023] In one embodiment, a reflective polarizer may be provided on the opposite side of the outer protective layer 12 from the polarizer. The reflective polarizer may also serve as the outer protective layer. The polarizing plate of this embodiment is typically a rear-side polarizing plate. Details of the reflective polarizer are described in, for example, JP-A-9-507308 and JP-A-2013-235259. The descriptions in these publications are incorporated herein by reference.

[0024] When the polarizing plate according to the embodiment of the present invention is rectangular, the aspect ratio is preferably 1.3 to 2.5. In this case, the size of the polarizing plate is, for example, 145 mm to 155 mm in height and 65 mm to 75 mm in width, or 230 mm to 240 mm in height and 140 mm to 150 mm in width. That is, the polarizing plate according to the embodiment of the present invention can be suitably used in smartphones or tablet PCs. The size of a smartphone may be, for example, 120 mm to 200 mm in height and 30 mm to 120 mm in width.

[0025] The polarizer, protective layer and pressure-sensitive adhesive layer constituting the polarizing plate will be specifically described below.

[0026] B. Polarizing plate B-1.Polarizer A polarizer is typically made of a resin film containing a dichroic material. Any appropriate resin film that can be used as a polarizer can be adopted as the resin film. A typical resin film is a polyvinyl alcohol resin (hereinafter referred to as "PVA resin") film. The resin film may be a single-layer resin film or a laminate of two or more layers.

[0027] A specific example of a polarizer composed of a single-layer resin film is a PVA-based resin film that has been subjected to a dyeing treatment with iodine and a stretching treatment (typically, uniaxial stretching). The dyeing with iodine is performed, for example, by immersing the PVA-based resin film in an aqueous iodine solution. The stretching ratio of the uniaxial stretching is preferably 3 to 7 times. The stretching may be performed after the dyeing treatment or while dyeing. Alternatively, the film may be stretched and then dyed. If necessary, the PVA-based resin film is subjected to a swelling treatment, a crosslinking treatment, a washing treatment, a drying treatment, or the like. For example, by immersing the PVA-based resin film in water and washing it before dyeing, not only can dirt and antiblocking agents on the surface of the PVA-based resin film be washed off, but also the PVA-based resin film can be swelled to prevent uneven dyeing.

[0028] Specific examples of polarizers obtained using laminates include a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate. A polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate can be produced by, for example, applying a PVA-based resin solution to the resin substrate and drying the resin substrate to form a PVA-based resin layer on the resin substrate to obtain a laminate of the resin substrate and the PVA-based resin layer; stretching and dyeing the laminate to make the PVA-based resin layer a polarizer. In this embodiment, stretching typically includes immersing the laminate in an aqueous solution of boric acid to stretch it. Furthermore, stretching may further include, as necessary, stretching the laminate in air at a high temperature (for example, 95°C or higher) before stretching in the aqueous solution of boric acid. The obtained laminate of resin substrate / polarizer may be used as it is (i.e., the resin substrate may be used as a protective layer for the polarizer), or the resin substrate may be peeled off from the laminate of resin substrate / polarizer, and any suitable protective layer may be laminated on the peeled surface depending on the purpose. Details of the method for producing such a polarizer are described in, for example, JP2012-73580A and JP6470455A. The descriptions in these patent documents are incorporated herein by reference.

[0029] The thickness of the polarizer is as described in section A above.

[0030] The polarizer preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The single transmittance of the polarizer is, for example, 41.5% to 46.0%, preferably 43.0% to 46.0%, and more preferably 44.5% to 46.0%. The degree of polarization of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and even more preferably 99.9% or more.

[0031] B-2.Protective layer The protective layer is formed of any suitable film that can be used as a protective layer for a polarizer. Specific examples of materials that are the main components of the film include cellulose-based resins such as triacetyl cellulose (TAC), and transparent resins such as polyesters, polyvinyl alcohols, polycarbonates, polyamides, polyimides, polyethersulfones, polysulfones, polystyrenes, polynorbornenes, polyolefins, (meth)acrylics, and acetates. Other examples include thermosetting resins or ultraviolet-curing resins such as (meth)acrylics, urethanes, (meth)acrylic urethanes, epoxys, and silicones. Other examples include glassy polymers such as siloxane polymers. Polymer films described in JP 2001-343529 A (WO01 / 37007) can also be used. The material for this film may be, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain, and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain, such as a resin composition containing an alternating copolymer of isobutene and N-methylmaleimide, and an acrylonitrile-styrene copolymer. The polymer film may be, for example, an extrusion molded product of the above resin composition.

[0032] The outer protective layer 12 (particularly when the polarizing plate is the viewing side polarizing plate) may be subjected to a surface treatment such as a hard coat treatment, an anti-reflection treatment, an anti-sticking treatment, an anti-glare treatment, etc., as necessary. Additionally / alternatively, the outer protective layer 12 may be subjected to a treatment for improving visibility when viewed through polarized sunglasses (typically, imparting an (elliptical) polarization function or imparting an ultra-high phase difference) as necessary. By performing such a treatment, excellent visibility can be achieved even when the display screen is viewed through polarized lenses such as polarized sunglasses. Therefore, the polarizing plate can be suitably applied to an image display device that can be used outdoors.

[0033] The inner protective layer is preferably optically isotropic. In this specification, "optically isotropic" means that the in-plane retardation Re(550) is 0 nm to 10 nm, and the retardation in the thickness direction Rth(550) is -10 nm to +10 nm. Here, "Rth(λ)" is the retardation in the thickness direction measured with light having a wavelength of λ nm at 23°C. For example, "Rth(550)" is the retardation in the thickness direction measured with light having a wavelength of 550 nm at 23°C. Rth(λ) is calculated by the formula: Rth(λ)=(nx-nz)×d, where d(nm) is the thickness of the layer (film). nz is the refractive index in the thickness direction.

[0034] The thickness of the protective layer may be any appropriate thickness. The thickness of the protective layer is, for example, 10 μm to 50 μm, and preferably 20 μm to 40 μm. In addition, when a surface treatment is performed, the thickness of the protective layer includes the thickness of the surface treatment layer.

[0035] C.Adhesive layer The adhesive layer 20 is used to bond the polarizing plate to the image display cell as described above. The adhesive layer may typically be composed of an acrylic adhesive (acrylic adhesive composition). The acrylic adhesive composition typically contains a (meth)acrylic polymer as a main component. The (meth)acrylic polymer may be contained in the adhesive composition at a ratio of, for example, 50% by weight or more, preferably 70% by weight or more, and more preferably 90% by weight or more in the solid content of the adhesive composition. The (meth)acrylic polymer contains an alkyl (meth)acrylate as a monomer unit as a main component. Here, (meth)acrylate refers to acrylate and / or methacrylate. The alkyl (meth)acrylate may be contained in a ratio of preferably 80% by weight or more, more preferably 90% by weight or more in the monomer components forming the (meth)acrylic polymer. 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 of the alkyl group is preferably 3 to 9, more preferably 3 to 6. A preferred alkyl (meth)acrylate is butyl acrylate. Examples of monomers (copolymerizable monomers) constituting the (meth)acrylic polymer include, in addition to alkyl (meth)acrylates, carboxyl group-containing monomers, hydroxyl group-containing monomers, amide group-containing monomers, aromatic ring-containing (meth)acrylates, and heterocycle-containing vinyl monomers. Representative examples of copolymerizable monomers include acrylic acid, 4-hydroxybutyl acrylate, phenoxyethyl acrylate, and N-vinyl-2-pyrrolidone. The acrylic adhesive composition may preferably contain a silane coupling agent and / or a crosslinking agent. Examples of the silane coupling agent include an epoxy group-containing silane coupling agent. Examples of the crosslinking agent include an isocyanate-based crosslinking agent and a peroxide-based crosslinking agent. Furthermore, the acrylic adhesive composition may contain an antioxidant and / or a conductive agent. The thickness of the pressure-sensitive adhesive layer is, for example, 50 μm or less, and as described above, is preferably 22 μm or less, and more preferably 10 μm to 22 μm.Details of the pressure-sensitive adhesive layer or the acrylic pressure-sensitive adhesive composition are described, for example, in JP 2006-183022 A, JP 2015-199942 A, JP 2018-053114 A, JP 2016-190996 A, and WO 2018 / 008712, the disclosures of which are incorporated herein by reference.

[0036] The creep value of the adhesive layer is preferably 140 μm / hr or less, more preferably 100 μm / hr or less, even more preferably 75 μm / hr or less, and particularly preferably 50 μm / hr or less. The lower limit of the creep value may be, for example, 20 μm / hr. In this specification, the "creep value" means the creep value at 85°C. The creep value can be measured, for example, by the following procedure: the adhesive constituting the adhesive layer is attached to a support plate. With the support plate to which the adhesive is attached being fixed, a load of 500 g is applied vertically downward. The amount of displacement of the adhesive from the support plate one hour after the load is applied is measured, and the amount of displacement is taken as the creep value (μm / hr).

[0037] The storage modulus G2' of the pressure-sensitive adhesive layer at -40°C is preferably 1.0 x 10 5 (Pa) or more, and more preferably 1.0×10 6 (Pa) or more, and more preferably 1.0×10 7 (Pa) or more, and particularly preferably 1.0×10 8 (Pa) or more. The storage modulus G2' is, for example, 1.0 × 10 9 The storage modulus G3′ of the pressure-sensitive adhesive layer at 85° C. is preferably 1.0×10 5 (Pa) or more, and more preferably 3.0×10 5 (Pa) or more, and more preferably 5.0×10 5 (Pa) or more. The storage modulus G3' is, for example, 1.0×10 6 (Pa) or less.

[0038] D. Image display device The polarizing plate according to the embodiment of the present invention can be applied to an image display device. Therefore, the image display device is also included in the embodiment of the present invention. The image display device includes an image display cell and a polarizing plate. The polarizing plate is the polarizing plate according to the embodiment of the present invention described in the above items A to C. The polarizing plate is attached to the image display cell via an adhesive layer. Examples of the image display device include a liquid crystal display device, an organic electroluminescence (EL) display device, and a quantum dot display device.

[0039] E. Polarizing plate with cover glass When the polarizing plate according to the embodiment of the present invention is applied to the viewing side of an image display device, a cover glass may be attached to the polarizing plate via another adhesive layer (hereinafter, sometimes referred to as a second adhesive layer). Therefore, the embodiment of the present invention includes a polarizing plate with a cover glass layer. The polarizing plate according to the embodiment of the present invention may be provided in a form in which a separator is temporarily attached instead of the cover glass. In this case, when the image display device is produced, the separator is peeled off and removed, and the cover glass is attached via the exposed second adhesive layer. In either case, the through hole can be typically filled with an adhesive constituting the second adhesive layer. The adhesive constituting the second adhesive layer will be described below.

[0040] The pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer typically has a storage modulus of 1.0×10 at 60° C. when the second pressure-sensitive adhesive layer is laminated to a polarizing plate. 4 Pa~1.0×10 5Pa. The adhesive constituting the second adhesive layer can be any appropriate adhesive as long as it has such a storage modulus when laminated. Specifically, the adhesive may be a photocurable adhesive or a non-curable adhesive. In this specification, the "photocurable adhesive" refers to an adhesive in which a crosslinking reaction proceeds by light irradiation. Therefore, the photocurable adhesive is soft and has excellent deformability when laminated, and the desired properties (e.g., storage modulus) can be imparted to the adhesive layer by light irradiation after lamination. As a result, the photocurable adhesive is extremely excellent in filling the irregularly processed part, and the thickness of the second adhesive layer (and, as a result, the image display device) can be made thin. Furthermore, even if a thick frame printing layer is formed on the cover glass, for example, good adhesion can be ensured. The "non-curable adhesive" refers to an adhesive in which the crosslinking reaction has substantially ended and the crosslinking reaction does not substantially proceed after lamination. In other words, the non-curable adhesive can be a so-called normal adhesive. Non-curable adhesives are excellent in productivity because they do not require light irradiation (photo-curing), and furthermore, they can prevent the occurrence of dents, the adhesive spilling out from the edges of the punched product, handling problems, and the like.

[0041] The storage modulus at 60°C before curing of the photocurable pressure-sensitive adhesive can substantially correspond to the storage modulus at the time of lamination. As described above, the storage modulus before curing is 1.0 × 10 5 Pa or less, preferably 1.0×10 3 Pa~1.0×10 5 The storage modulus of the photocurable adhesive at 60° C. after curing is preferably 5.0×10 3 Pa~5.0×10 5 The gel fraction of the photocurable adhesive before curing is 0% to 60%, and the gel fraction after curing is 50% to 95%. When the second adhesive layer is composed of a photocurable adhesive, the thickness of the second adhesive layer is preferably 50 μm to 500 μm, more preferably 75 μm to 475 μm, and even more preferably 100 μm to 450 μm.

[0042] The storage modulus of the non-curable adhesive at 60°C during lamination is preferably 1.0 x 10 3 Pa~8.0×10 4 Pa, more preferably 5.0×10 3 Pa ~ 6.0 × 10 4 Pa. When the second pressure-sensitive adhesive layer is composed of a non-curable pressure-sensitive adhesive, the thickness of the second pressure-sensitive adhesive layer is preferably 50 μm to 1000 μm, more preferably 75 μm to 900 μm, and even more preferably 100 μm to 800 μm.

[0043] The characteristics of the second adhesive layer and the photocurable adhesive constituting the second adhesive layer will be described below, followed by a brief description of the non-curable adhesive.

[0044] E-1. Characteristics of the second adhesive layer The glass transition temperature of the second pressure-sensitive adhesive layer is preferably −3° C. or lower, more preferably −5° C. or lower, and even more preferably −6° C. or lower. Meanwhile, the glass transition temperature is preferably −20° C. or higher, more preferably −15° C. or higher, and even more preferably −13° C. or higher. If the glass transition temperature is within such a range, a second pressure-sensitive adhesive layer having excellent impact resistance can be realized.

[0045] The peak top value of the loss tangent tanδ of the second pressure-sensitive adhesive layer (i.e., tanδ at the glass transition temperature) is preferably 1.5 or more, more preferably 1.6 or more, even more preferably 1.7 or more, and particularly preferably 1.75 or more. Meanwhile, the upper limit of the peak top value of tanδ is preferably 3.0 or less, more preferably 2.5 or less, and even more preferably 2.3 or less. If the peak top value of tanδ is within such a range, the second pressure-sensitive adhesive layer exhibits appropriate deformation behavior (viscoelastic behavior), so that gaps are less likely to form in the irregularly processed portion, and delayables can be suppressed.

[0046] The second pressure-sensitive adhesive layer has a total light transmittance of preferably 85% or more, more preferably 90% or more. The second pressure-sensitive adhesive layer has a haze value of preferably 1.5% or less, more preferably 1.0% or less.

[0047] E-2. Light-curing adhesive E-2-1. Characteristics of light-curing adhesives The storage modulus of the photocurable adhesive at 60°C before curing is 1.0 × 10 5 Pa or less, preferably 1.0×10 3 Pa~1.0×10 5 Pa, more preferably 5.0×10 3 Pa~8.0×10 4 Pa, and more preferably 7.5×10 3 Pa ~ 6.0 × 10 4 When the storage modulus of the photocurable adhesive before curing is within this range, the photocurable adhesive exhibits appropriate deformation behavior (viscoelastic behavior) and can flow smoothly into every corner of the irregularly shaped processed portion. As a result, gaps are less likely to form in the irregularly shaped processed portion, and delay bubbles can be suppressed. The storage modulus of the photocurable adhesive at 60°C after curing is preferably 5.0 x 10 3 Pa~5.0×10 5 Pa, more preferably 7.5×10 3 Pa ~ 4.0 × 10 5 Pa, and more preferably 8.0×10 3 Pa~3.0×10 5 When the storage modulus of the photocurable adhesive after curing is within this range, the gel elasticity of the second adhesive is low, and the residual stress is small. As a result, delayables can be suppressed.

[0048] The gel fraction of the photocurable adhesive before curing is preferably 0% to 60%, more preferably 0% to 55%, and even more preferably 0% to 50%. If the gel fraction of the photocurable adhesive before curing is in such a range, the desired storage modulus can be easily achieved. Therefore, the photocurable adhesive exhibits appropriate deformation behavior (viscoelastic behavior) and can flow well into every corner of the irregularly processed portion. As a result, gaps are less likely to be formed in the irregularly processed portion, and delay bubbles can be suppressed. The gel fraction of the photocurable adhesive after curing is preferably 50% to 95%, more preferably 55% to 93%, and even more preferably 60% to 90%. If the gel fraction of the photocurable adhesive after curing is in such a range, the cover glass, the first polarizing plate, and the image display cell can be firmly fixed. As a result, delay bubbles can be suppressed. The gel fraction can be determined as the insoluble matter in a solvent such as ethyl acetate. Specifically, the gel fraction is determined as the weight fraction (unit: weight %) of the insoluble components after immersing the adhesive constituting the adhesive layer in ethyl acetate for 7 days at 23° C. relative to the sample before immersion. The gel fraction can be adjusted by appropriately setting the types, combinations and amounts of monomer components constituting the base polymer of the adhesive, and the type and amount of the crosslinking agent.

[0049] E-2-2. Materials for photocurable adhesives As the photocurable adhesive, any suitable photocurable adhesive (sometimes simply referred to as adhesive composition in this section) can be used as long as it has the above-mentioned properties. Examples of the base polymer of the adhesive composition include (meth)acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyvinyl ethers, vinyl acetate / vinyl chloride copolymers, modified polyolefins, epoxy polymers, fluorine polymers, natural rubber, synthetic rubber, and other rubber-based polymers. A (meth)acrylic adhesive composition containing a (meth)acrylic polymer as the base polymer is preferable. This is because it has excellent optical transparency, exhibits adhesive properties such as moderate wettability, cohesiveness, and adhesiveness, and is also excellent in weather resistance and heat resistance. In this specification, "(meth)acrylic" means acrylic and / or methacrylic.

[0050] The (meth)acrylic base polymer (hereinafter sometimes simply referred to as the base polymer) preferably has a crosslinked structure.

[0051] E-2-2-1.(Meth)acrylic-based polymer The (meth)acrylic base polymer contains an alkyl (meth)acrylate as a main monomer component. As the alkyl (meth)acrylate, an alkyl (meth)acrylate having 1 to 20 carbon atoms in the alkyl group is preferably used. The alkyl group in the alkyl (meth)acrylate may have a branched alkyl group or may have a cyclic alkyl group. The amount of the alkyl (meth)acrylate relative to the total amount of the monomer components constituting the (meth)acrylic base polymer is preferably 40% by weight or more, more preferably 50% by weight or more, and even more preferably 60% by weight or more. From the viewpoint of setting the glass transition temperature (Tg) of the polymer chain in an appropriate range, the amount of the alkyl (meth)acrylate having a chain alkyl group having 4 to 10 carbon atoms relative to the total amount of the monomer components constituting the (meth)acrylic base polymer is preferably 30% by weight or more, more preferably 40% by weight or more, and even more preferably 45% by weight or more.

[0052] The (meth)acrylic base polymer preferably contains a monomer component having a crosslinkable functional group. With this configuration, the gel fraction of the adhesive can be adjusted to a desired range. Examples of monomer components having a crosslinkable functional group include hydroxyl group-containing monomers and carboxyl group-containing monomers. When a crosslinked structure is introduced by an isocyanate crosslinking agent, the hydroxyl group becomes a reaction point with the isocyanate group, and when a crosslinked structure is introduced by an epoxy crosslinking agent, the carboxyl group becomes a reaction point with the epoxy group. Preferably, a hydroxyl group-containing monomer is used as the monomer component having a crosslinkable functional group, and a crosslinked structure can be introduced by an isocyanate crosslinking agent. With this configuration, the crosslinking property of the base polymer is enhanced, and a second adhesive layer having high transparency can be obtained. Furthermore, with this configuration, a so-called acid-free adhesive can be realized.

[0053] The amount of the hydroxyl group-containing monomer relative to the total amount of the monomer components constituting the (meth)acrylic base polymer is preferably 5% by weight to 30% by weight, more preferably 8% by weight to 25% by weight, and even more preferably 10% by weight to 20% by weight. If the amount of the hydroxyl group-containing monomer is within such a range, the degree of crosslinking (gel fraction) can be increased with a small amount of crosslinking agent, and as a result, the filling ability and operability of the irregularly processed part of the photocurable adhesive before curing can be improved. Furthermore, since unreacted hydroxyl groups can form intermolecular hydrogen bonds after crosslinking, a desired storage modulus can be achieved even if the gel fraction is small.

[0054] When the second adhesive layer may come into contact with, for example, a touch panel sensor, it is preferable that the second adhesive layer has a small acid content in order to prevent corrosion of the electrode by the acid component. In this case, the amount of the carboxyl group-containing monomer relative to the total amount of the monomer components constituting the (meth)acrylic base polymer is preferably 0.5 wt% or less, more preferably 0.1 wt% or less, even more preferably 0.05 wt% or less, and ideally 0 (zero). With this configuration, the acid content in the photocurable adhesive can be preferably 100 ppm or less, more preferably 70 ppm or less, and even more preferably 50 ppm or less.

[0055] The (meth)acrylic base polymer may contain a nitrogen-containing monomer as a monomer component. The (meth)acrylic base polymer appropriately contains a highly polar monomer such as a hydroxyl group-containing monomer, a carboxyl group-containing monomer, and a nitrogen-containing monomer as a monomer component, thereby forming a second pressure-sensitive adhesive layer having an excellent balance of storage modulus, adhesive retention, and impact resistance. The amount of highly polar monomer (total of hydroxyl group-containing monomer, carboxyl group-containing monomer, and nitrogen-containing monomer) relative to the total amount of monomer components constituting the (meth)acrylic base polymer is preferably 10% by weight to 45% by weight, more preferably 15% by weight to 40% by weight, and even more preferably 18% by weight to 35% by weight. In particular, it is preferable that the total of the hydroxyl group-containing monomer and the nitrogen-containing monomer is within the above range. The amount of the nitrogen-containing monomer relative to the total amount of monomer components constituting the (meth)acrylic base polymer is preferably 3% by weight to 25% by weight, more preferably 5% by weight to 20% by weight, and even more preferably 7% by weight to 15% by weight.

[0056] The (meth)acrylic polymer may further contain any suitable monomer component depending on the purpose. Specific examples of such monomer components include vinyl monomers such as acid anhydride group-containing monomers, caprolactone adducts of (meth)acrylic acid, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, vinyl acetate, vinyl propionate, styrene, and α-methylstyrene; cyano group-containing acrylic monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing monomers such as glycidyl (meth)acrylate; glycol-based acrylic ester monomers such as polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate; tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, silicone (meth)acrylate, and 2-methoxyethyl (meth)acrylate.

[0057] The (meth)acrylic base polymer preferably contains the most alkyl (meth)acrylate as a monomer component, and more preferably contains the most alkyl (meth)acrylate having a chain alkyl group having 6 or less carbon atoms. With such a configuration, the peak top value of tan δ becomes large, and impact resistance can be improved. The amount of the alkyl (meth)acrylate having a chain alkyl group having 6 or less carbon atoms relative to the total amount of the monomer components constituting the (meth)acrylic base polymer is preferably 30% by weight to 80% by weight, more preferably 35% by weight to 75% by weight, and even more preferably 40% by weight to 70% by weight. In particular, it is preferable that the content of butyl acrylate as a monomer component is within the above range.

[0058] The glass transition temperature (Tg) of the (meth)acrylic base polymer is preferably −50° C. or higher. On the other hand, the Tg of the (meth)acrylic base polymer is preferably −5° C. or lower, more preferably −10° C. or lower, and even more preferably −15° C. or lower.

[0059] E-2-2-2.Crosslinked structure A polymer in which a crosslinked structure is introduced into a (meth)acrylic base polymer can be obtained, for example, by (1) a method in which a (meth)acrylic polymer having a functional group capable of reacting with a crosslinking agent is polymerized, and then a crosslinking agent is added to react the (meth)acrylic polymer with the crosslinking agent; and (2) a method in which a branched structure (crosslinked structure) is introduced into a polymer chain by including a multifunctional compound in the polymerization components of the polymer, etc. These methods may be used in combination.

[0060] Specific examples of the crosslinking agent in the above method (1) of reacting the base polymer with the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, carbodiimide-based crosslinking agents, and metal chelate-based crosslinking agents. Among them, isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferred because they are highly reactive with the hydroxyl groups and carboxyl groups of the base polymer and can easily introduce a crosslinked structure. These crosslinking agents react with functional groups such as hydroxyl groups and carboxyl groups introduced into the base polymer to form a crosslinked structure. As described above, when an acid-free adhesive in which the base polymer does not contain a carboxyl group is used, it is preferable to introduce a crosslinked structure using the hydroxyl groups in the base polymer and an isocyanate-based crosslinking agent.

[0061] The crosslinking agent can be used in an amount of preferably 0.03 to 0.5 parts by weight, more preferably 0.05 to 0.3 parts by weight, still more preferably 0.06 to 0.25 parts by weight, and particularly preferably 0.07 to 0.2 parts by weight, relative to 100 parts by weight of the base polymer. By setting the amount of the crosslinking agent used within this range, the gel fraction can be set within the desired range.

[0062] E-2-2-3. Polyfunctional compounds In the method (2) of including a polyfunctional compound in the polymerization components of the base polymer, the monomer components constituting the (meth)acrylic base polymer and the polyfunctional compound for introducing a crosslinking structure may be reacted in their entirety at once, or the polymerization may be carried out in multiple stages. As a method of carrying out polymerization in multiple stages, a method is preferred in which a monofunctional monomer constituting the (meth)acrylic base polymer is polymerized (preliminarily polymerized) to prepare a partial polymer (prepolymer composition), and a polyfunctional compound such as a polyfunctional (meth)acrylate is added to the prepolymer composition to polymerize the prepolymer composition and the polyfunctional monomer (main polymerization). The prepolymer composition is a partial polymer containing a polymer with a low degree of polymerization and an unreacted monomer.

[0063] By carrying out prepolymerization of the constituents of the (meth)acrylic base polymer, branch points (crosslinking points) due to the polyfunctional compound can be uniformly introduced into the (meth)acrylic base polymer. In addition, a mixture (adhesive composition) of a low molecular weight polymer or a partially polymerized product and an unpolymerized monomer component can be applied onto a substrate, and then main polymerization can be carried out on the substrate to form a pressure-sensitive adhesive layer. Since low-polymer compositions such as prepolymer compositions have low viscosity and excellent applicability, the method of carrying out main polymerization on a substrate after applying a pressure-sensitive adhesive composition, which is a mixture of a prepolymer composition and a polyfunctional compound, can improve the productivity of the pressure-sensitive adhesive layer and make the thickness of the pressure-sensitive adhesive layer uniform.

[0064] The polyfunctional compound used for introducing the crosslinked structure may be a compound containing two or more polymerizable functional groups (ethylenically unsaturated groups) having an unsaturated double bond in one molecule. The polyfunctional compound is typically a photopolymerizable polyfunctional compound. As the polyfunctional compound, a polyfunctional (meth)acrylate is preferred because it is easily copolymerized with the monomer component of the (meth)acrylic polymer. When introducing a branched (crosslinked) structure by active energy ray polymerization (photopolymerization), a polyfunctional (meth)acrylate is preferred.

[0065] The molecular weight of the polyfunctional compound is preferably 1500 or less, more preferably 1000 or less. The lower limit of the molecular weight may be, for example, 500. The functional group equivalent (g / eq) of the polyfunctional compound is preferably 50 to 500, more preferably 70 to 300, and further preferably 80 to 200. With this configuration, the viscoelasticity of the photocurable pressure-sensitive adhesive can be appropriately adjusted.

[0066] The polyfunctional compound may be used in an amount of preferably 1 to 6 parts by weight, more preferably 2 to 5 parts by weight, and even more preferably 2.5 to 4 parts by weight, based on 100 parts by weight of the base polymer. If the amount used is too small, the adhesion retention of the photocurable adhesive (and consequently the second adhesive layer) may be insufficient. If the amount used is too large, the second adhesive layer formed may be excessively hard and may have insufficient impact resistance. Furthermore, the processability and / or processing dimensional stability of the photocurable adhesive may be insufficient.

[0067] In one embodiment, the polyfunctional compound may be a compound having three or more photopolymerizable functional groups in one molecule, and more preferably may be a (meth)acrylate having three or more photopolymerizable functional groups in one molecule. By using a trifunctional or higher functional photopolymerizable compound, the adhesion retention of the photocurable adhesive (as a result, the second adhesive layer) can be further improved. A bifunctional photopolymerizable compound and a trifunctional or higher functional photopolymerizable compound may be used in combination. The trifunctional or higher functional photopolymerizable compound may be used in a ratio of preferably 0.5 to 5 parts by weight, more preferably 1 to 4.5 parts by weight, and even more preferably 2 to 4 parts by weight, relative to 100 parts by weight of the base polymer.

[0068] E-2-2-4. Pressure-sensitive adhesive composition The pressure-sensitive adhesive composition (photocurable pressure-sensitive adhesive) may contain, in addition to the above-mentioned base polymer, crosslinking agent, and polyfunctional compound, a photopolymerization initiator, an oligomer, a silane coupling agent, and any suitable additives depending on the purpose.

[0069] Examples of the photopolymerization initiator include benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-ketol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, and acylphosphine oxide-based photopolymerization initiators. The photopolymerization initiators may be used alone or in combination of two or more. The content of the photopolymerization initiator in the pressure-sensitive adhesive composition is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 3 parts by weight, based on 100 parts by weight of the base polymer.

[0070] As the oligomer, any suitable oligomer can be used. By using the oligomer, the viscoelasticity (hence, the filling property and workability of the irregular processed part) and adhesive strength of the photocurable pressure-sensitive adhesive can be adjusted. The oligomer is preferably a (meth)acrylic oligomer. The (meth)acrylic oligomer can have excellent compatibility with the base polymer.

[0071] The weight average molecular weight of the oligomer is preferably about 1000 to 30000, more preferably 1500 to 10000, and further preferably 2000 to 8000. When the weight average molecular weight of the oligomer is within such a range, excellent adhesive strength and adhesion retention can be achieved.

[0072] The Tg of the oligomer is preferably 20° C. or higher, more preferably 50° C. or higher, even more preferably 80° C. or higher, and particularly preferably 100° C. or higher. On the other hand, the Tg of the oligomer is preferably 200° C. or lower, more preferably 180° C. or lower, and even more preferably 160° C. or lower. When the Tg of the oligomer is within this range, a second pressure-sensitive adhesive layer having excellent adhesive strength can be formed.

[0073] The content of the oligomer in the pressure-sensitive adhesive composition is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the base polymer. When the content of the oligomer is within this range, a second pressure-sensitive adhesive layer having excellent adhesive strength can be formed while maintaining good processability and processing dimensional stability of the photocurable pressure-sensitive adhesive.

[0074] Any suitable silane coupling agent can be used as the silane coupling agent. By using the silane coupling agent, the adhesive strength of the photocurable adhesive can be adjusted. The content of the silane coupling agent in the adhesive composition is preferably 0.01 to 5 parts by weight, more preferably 0.03 to 2 parts by weight, based on 100 parts by weight of the base polymer.

[0075] Regarding the additives, any appropriate additives depending on the purpose can be used.

[0076] In one embodiment, the pressure-sensitive adhesive composition (photocurable pressure-sensitive adhesive) has a thickness corresponding to the thickness of the second pressure-sensitive adhesive layer, and can be provided as a pressure-sensitive adhesive sheet with release films temporarily attached to both sides.

[0077] Further details of the adhesive composition (photocurable adhesive) are described in Japanese Patent Application No. 2018-218422 by the present applicant, the disclosure of which is incorporated herein by reference.

[0078] E-3.Non-curing adhesive As the non-curing adhesive, any suitable non-curing adhesive can be used as long as it has the above-mentioned characteristics. By appropriately adjusting the type, combination, and blending amount of the monomer components, as well as the type, number, combination, and blending amount of the crosslinking agent, silane coupling agent, and additives, a non-curing adhesive (as a result, the second adhesive layer) having the desired storage modulus can be obtained. Examples of the non-curing adhesive include the adhesives described in Section C above regarding the first and second adhesive layers, the adhesives described in Japanese Patent Application No. 2019-196942 by the present applicant, and the adhesives described in Japanese Patent Publication No. 2016-94569. The descriptions in the application and publication are incorporated herein by reference.

[0079] E-4. Setting optical components As described above, the adhesive (adhesive composition) constituting the second adhesive layer may be provided as an adhesive sheet. In the production of an image display device, the adhesive sheet may be provided as a set of optical members together with a polarizing plate according to an embodiment of the present invention. Therefore, such a set of optical members is also included in the embodiment of the present invention. In one embodiment, the set of optical members may further include another polarizing plate (rear-side polarizing plate). That is, in the production of an image display device, the adhesive sheet, the polarizing plate according to an embodiment of the present invention (viewer-side polarizing plate), and the second polarizing plate (rear-side polarizing plate) may be provided as a set of optical members. EXAMPLES

[0080] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The evaluation items in the examples are as follows. In addition, unless otherwise specified, "parts" and "%" in the examples are based on weight.

[0081] (1) Size of the adhesive gap The cross-sectional condition of the adhesive layer in the through holes of the polarizing plates used in the examples and comparative examples was observed with an optical microscope, and the length of the part where the adhesive layer was missing the most from the outer edge inward in the planar direction was measured, and this was recorded as the size L (μm) of the adhesive void. (2) Amount of adhesive shift The polarizing plates used in the examples and comparative examples were attached to glass, autoclaved (50°C / 0.5MPa / 15min), and then subjected to a heating test (85°C, 120h). The through holes of the samples after the test were observed with an optical microscope, and the deformed portion of the adhesive at the polarizing plate end of the through hole was measured and recorded as the displacement of the through hole. The deformed portion was measured with an optical microscope (MX61L) manufactured by OLYMPUS. The measurement was performed on three test samples, and the maximum value of the three measured values ​​was recorded as the displacement. (3) Air bubble evaluation The image display device-compatible products obtained in the examples and comparative examples were vacuum laminated, autoclaved (50°C / 0.5MPa / 15min), and UV cured (illuminance 150mW / cm 2 The sample was then placed in a heating test (85°C, 24 hours) and the state of bubbles was observed visually or with an optical microscope when it was removed. Measurements were performed on n=6 samples and evaluated according to the following criteria. 4: No air bubbles were observed in any of the samples. 3: Less than half of the samples have slight air bubbles, but they do not affect use. 2: More than half of the samples had slight air bubbles, but no problems with use. 1: All samples have air bubbles

[0082] <Production Example 1: Preparation of Adhesive Layer (1)> A monomer mixture containing 99 parts of butyl acrylate (BA) and 1 part of 4-hydroxybutyl acrylate was charged into a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser. Furthermore, 0.1 parts of 2,2'-azobisisobutyronitrile as a polymerization initiator was charged together with 100 parts by weight of ethyl acetate per 100 parts of the monomer mixture (solid content), and nitrogen gas was introduced while gently stirring to replace the atmosphere with nitrogen. The liquid temperature in the flask was kept at around 55°C, and a polymerization reaction was carried out for 8 hours to prepare an acrylic polymer solution. A pressure-sensitive adhesive composition was obtained by blending 100 parts of the solid content of the obtained acrylic polymer solution with 0.3 parts of benzoyl peroxide (product name: Niper BMT 40SV, manufactured by Nippon Oil & Fats Co., Ltd.) as a crosslinking agent, 0.1 parts of an isocyanate crosslinking agent (product name: Takenate D110N, manufactured by Mitsui Chemicals, Inc.), and 0.2 parts of a silane coupling agent (product name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.). Next, the solution of the acrylic adhesive composition was applied to one side of a polyethylene terephthalate film (separator film: MRF38, manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.) treated with a silicone release agent so that the adhesive layer would have a thickness of 20 μm after drying, and dried at 155° C. for 1 minute to form an adhesive layer (1) on the surface of the separator film. The creep value of the adhesive layer (1) was 120 μm / hr.

[0083] <Production Example 2: Preparation of Adhesive Layer (2)> A monomer mixture containing 94.9 parts of butyl acrylate (BA), 5 parts of acrylic acid, and 0.1 parts of 4-hydroxybutyl acrylate was charged into a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser. Furthermore, 0.1 parts of 2,2'-azobisisobutyronitrile as a polymerization initiator was charged together with 100 parts by weight of ethyl acetate per 100 parts of the monomer mixture (solid content), and nitrogen gas was introduced while gently stirring to replace the atmosphere with nitrogen. The liquid temperature in the flask was kept at around 55°C, and a polymerization reaction was carried out for 8 hours to prepare an acrylic polymer solution. A pressure-sensitive adhesive composition was obtained by blending 100 parts of the solid content of the obtained acrylic polymer solution with 0.1 part of benzoyl peroxide (product name: Niper BMT 40SV, manufactured by Nippon Oil & Fats Co., Ltd.) as a crosslinking agent, 8 parts of an isocyanate crosslinking agent (product name: Coronate L, manufactured by Tosoh Corporation), and 0.2 parts of a silane coupling agent (product name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.). Next, the solution of the acrylic adhesive composition was applied to one side of a polyethylene terephthalate film (separator film: Mitsubishi Chemical Polyester Film Co., Ltd., MRF38) treated with a silicone release agent so that the adhesive layer would have a thickness of 20 μm after drying, and dried at 155° C. for 1 minute to form an adhesive layer (2) on the surface of the separator film. The creep value of the adhesive layer (2) was 35 μm / hr.

[0084] <Production Example 3: Preparation of photocurable adhesive constituting second adhesive layer> A monomer mixture containing 65 parts of butyl acrylate (BA), 5 parts of cyclohexyl acrylate (CHA), 10 parts of N-vinyl-2-pyrrolidone (NVP), 15 parts of 4-hydroxybutyl acrylate (4HBA) and 5 parts of isostearyl acrylate (ISTA) was charged. Furthermore, 0.2 parts of 2,2'-azobisisobutyronitrile as a polymerization initiator and 0.065 parts of α-thioglycerol (TGR) as a chain transfer agent were charged together with 233 parts by weight of ethyl acetate per 100 parts of the monomer mixture (solid content), and the mixture was stirred for 1 hour under a nitrogen atmosphere at 23°C, followed by nitrogen substitution. Thereafter, the mixture was reacted at 56°C for 5 hours, and then reacted at 70°C for 3 hours to prepare a solution of an acrylic base polymer. The following post-added components were added to 100 parts of the base polymer in the solution of the acrylic base polymer obtained above, and mixed uniformly to prepare a photocurable adhesive b. The storage modulus of photocurable adhesive b at 60°C before curing is 4.7×10 4 The storage modulus at 60°C after curing is 1.0×10 5 Pa. The gel fraction before curing was 40%, and the gel fraction after curing was 80%. (Post-added ingredients) Dipentaerythritol hexaacrylate as a polyfunctional compound (photohardener): Part 2 Polypropylene glycol diacrylate as a multifunctional compound (photocuring agent) (product name: APG400, manufactured by Shin-Nakamura Chemical Co., Ltd., polypropylene glycol #400 (n=7) diacrylate, functional group equivalent 268 g / eq): 3 parts Photopolymerization initiator (product name: Irgacure 184, manufactured by BASF): 0.2 parts (Preparation of adhesive sheet) A photocurable adhesive b was applied to a 75 μm thick polyethylene terephthalate (PET) film (Mitsubishi Chemical Corporation's "Diafoil MRF75") with a silicone-based release layer on its surface, and the film was heated at 100° C. for 3 minutes to remove the solvent, after which the same release PET film as above was attached to the surface. The laminate thus obtained was aged at 25° C. for 3 days to obtain an adhesive sheet I with release films temporarily attached to both sides.

[0085] <Production Example 4: Preparation of polarizing plate> A 30 μm thick polyvinyl alcohol film was stretched to 3 times while dyeing in a 0.3% concentration iodine solution at 30° C. for 1 minute between rolls with different speed ratios. Then, the film was stretched to 6 times the total stretch ratio while immersing in an aqueous solution containing 4% concentration boric acid and 10% concentration potassium iodide at 60° C. for 0.5 minutes. Next, the film was washed by immersing in an aqueous solution containing 1.5% concentration potassium iodide at 30° C. for 10 seconds, and then dried at 50° C. for 4 minutes to obtain a polarizer with a thickness of 12 μm. A triacetyl cellulose (TAC) film with a hard coat (hard coat thickness 2 μm, TAC thickness 25 μm) as an outer protective layer and a TAC film (thickness 25 μm) as an inner protective layer were bonded to both sides of this polarizer. A liquid crystal alignment solidified layer H and a liquid crystal alignment solidified layer Q were sequentially transferred to the inner protective layer side of this polarizing plate. In this manner, a polarizing plate (1) was produced. The liquid crystal alignment solidified layer H and the liquid crystal alignment solidified layer Q were prepared as follows.

[0086] A liquid crystal composition (coating liquid) was prepared by dissolving 10 g of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (manufactured by BASF: product name "Paliocolor LC242", represented by the following formula) and 3 g of a photopolymerization initiator for the polymerizable liquid crystal compound (manufactured by BASF: product name "Irgacure 907") in 40 g of toluene. [ka] The surface of a polyethylene terephthalate (PET) film (thickness 38 μm) was rubbed with a rubbing cloth and subjected to an alignment treatment. The direction of the alignment treatment was set to be 15° from the viewing side with respect to the direction of the absorption axis of the polarizer when it was attached to the polarizing plate. The above liquid crystal coating liquid was applied to this alignment-treated surface with a bar coater, and the liquid crystal compound was aligned by heating and drying at 90°C for 2 minutes. The liquid crystal layer thus formed was then irradiated with 1 mJ / cm using a metal halide lamp. 2The liquid crystal layer was cured by irradiating the liquid crystal with light of 1000 nm to form a liquid crystal alignment solidified layer H on the PET film. The liquid crystal alignment solidified layer H had a thickness of 2.5 μm and an in-plane retardation Re(550) of 270 nm. Furthermore, the liquid crystal alignment solidified layer H had a refractive index distribution of nx>ny=nz. A liquid crystal alignment solidified layer Q was formed on the PET film in the same manner as above, except that the coating thickness was changed and the orientation treatment direction was set to a 75° direction from the viewing side with respect to the direction of the absorption axis of the polarizer. The liquid crystal alignment solidified layer Q had a thickness of 1.5 μm and an in-plane retardation Re(550) of 140 nm. Furthermore, the liquid crystal alignment solidified layer Q had a refractive index distribution of nx>ny=nz.

[0087] <Production Example 5: Preparation of polarizing plate> A 30 μm thick polyvinyl alcohol film was stretched to 3 times while dyeing in a 0.3% concentration iodine solution at 30° C. for 1 minute between rolls with different speed ratios. Then, the film was stretched to 6 times the total stretch ratio while immersing in an aqueous solution containing 4% concentration boric acid and 10% concentration potassium iodide at 60° C. for 0.5 minutes. Next, the film was washed by immersing in an aqueous solution containing 1.5% concentration potassium iodide at 30° C. for 10 seconds, and then dried at 50° C. for 4 minutes to obtain a polarizer with a thickness of 12 μm. A triacetyl cellulose (TAC) film with a hard coat (hard coat thickness 2 μm, TAC thickness 25 μm) as an outer protective layer and an acrylic resin film (thickness 20 μm) as an inner protective layer were bonded to both sides of this polarizer, respectively, to prepare a polarizing plate (2).

[0088] <Production Example 6: Preparation of polarizing plate> 1. Preparation of Polarizer The thermoplastic resin substrate was a long amorphous isophthalic copolymerized polyethylene terephthalate film (thickness: 100 μm) having a water absorption rate of 0.75% and a Tg of about 75° C. One side of the resin substrate was subjected to a corona treatment. A PVA aqueous solution (coating solution) was prepared by adding 13 parts by weight of potassium iodide to 100 parts by weight of a PVA-based resin made by mixing polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., product name "GOHSEFFIMER Z410") in a ratio of 9:1, and dissolving the mixture in water. The above PVA aqueous solution was applied to the corona-treated surface of a resin substrate 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 at its free end to 2.4 times its original size in the machine direction (longitudinal direction) between rolls with different peripheral speeds in an oven at 130° C. (auxiliary air stretching treatment). Next, the laminate was immersed in an insolubilizing bath (a boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40° C. for 30 seconds (insolubilizing treatment). Next, the film was immersed in a dye bath (an aqueous iodine solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 with 100 parts by weight of water) at a liquid temperature of 30°C for 60 seconds while adjusting the concentration so that the single transmittance (Ts) of the final polarizing film would be a predetermined value (dyeing process). Next, the piece was immersed in a crosslinking bath (a boric acid aqueous solution obtained by mixing 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. for 30 seconds (crosslinking treatment). Thereafter, the laminate was immersed in an aqueous boric acid solution (boric acid concentration 4.0 wt %, potassium iodide 5.0 wt %) at a liquid temperature of 70°C and uniaxially stretched in the longitudinal direction (longitudinal direction) between rolls with different peripheral speeds so that the total stretch ratio was 5.5 times (underwater stretching treatment). Thereafter, the laminate was immersed in a cleaning bath (an aqueous solution obtained by mixing 4 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 maintained at 90°C, the laminate was brought into contact with a SUS heated roll whose surface temperature was maintained at 75°C for approximately 2 seconds (drying shrinkage treatment). The shrinkage rate of the laminate in the width direction due to the drying shrinkage treatment was 5.2%. In this manner, a polarizer having a thickness of 5 μm was formed on the resin substrate.

[0089] 2. Preparation of Polarizing Plates An HC-TAC film was attached to the polarizer surface of the resin substrate / polarizer laminate obtained above via an ultraviolet-curable adhesive. Specifically, the curable adhesive was applied to a thickness of 1.0 μm, and the layers were attached using a rolling machine. Then, UV rays were irradiated from the HC-TAC film side to cure the adhesive. The HC-TAC film was a film in which a hard coat (HC) layer (thickness 7 μm) was formed on a triacetyl cellulose (TAC) film (thickness 25 μm), and the TAC film was attached to the polarizer side. Next, the resin substrate was peeled off, and a TAC film (thickness 20 μm) was attached to the peeled surface in the same manner as above. In this manner, a polarizing plate (3) was produced.

[0090] <Example 1> 1. Formation of through holes The adhesive layer (1) obtained in Production Example 1 was formed on the surface of the liquid crystal alignment solidified layer Q of the polarizing plate (1) obtained in Production Example 4 to obtain a polarizing plate with an adhesive layer. This polarizing plate with an adhesive layer was punched out to a size of 145 mm in length and 68 mm in width. At this time, the polarizing plate was punched out so that the absorption axis direction of the polarizer was 135° clockwise with respect to the long side direction. Furthermore, a through hole with a diameter of 3.9 mm was formed by end mill processing in the upper right corner of the punched polarizing plate with an adhesive layer. In this way, a polarizing plate (polarizing plate with an adhesive layer) as shown in FIG. 1A was produced. In the obtained polarizing plate, |b1-b2| was 0 mm. In addition, the size L of the adhesive void was 90 μm. This polarizing plate was subjected to the evaluation of (2) above. The results are shown in Table 1.

[0091] 2. Production of image display device compatible products The polarizing plate with the adhesive layer obtained in 1 above was attached to one surface of a glass plate (corresponding to an image display cell) via the adhesive layer. Next, one release film of the adhesive sheet I obtained in Production Example 3 was peeled off, and the sheet was attached to a cover glass (manufactured by Matsunami Glass Co., Ltd., thickness 0.8 mm) using a roll laminator. Next, the other release film of the adhesive sheet I was peeled off, and the sheet was adhered to the surface of the polarizing plate with the adhesive layer using a vacuum laminator, and the through holes were filled with the adhesive sheet. The conditions for vacuum lamination were as follows: heating and pressing at 0.2 MPa and 60°C (waiting time 90 seconds), followed by vacuum lamination at 100 Pa for 10 seconds. Furthermore, a metal halide lamp (300 mW / cm) was used from the cover glass side. 2 ) with an accumulated light output of 3000mJ / cm 2 The photocurable adhesive was cured by irradiating it with ultraviolet light. Then, autoclaving (50°C / 0.5MPa / 15min) was performed. In this way, an image display device-compatible product was produced. The obtained image display device-compatible product was subjected to the air bubble evaluation described in (3) above. The results are shown in Table 1.

[0092] <Example 2> A polarizing plate (polarizing plate with adhesive layer) and a product for image display devices were produced in the same manner as in Example 1, except that the through holes were formed at the end in the long side direction and the center in the short side direction. |b1-b2| in the obtained polarizing plate was 41 mm. The size L of the adhesive void was 90 μm. The obtained polarizing plate and the product for image display devices were each subjected to the same evaluation as in Example 1. The results are shown in Table 1. In Table 1, the end in the long side direction and the center in the short side direction are simply referred to as "center".

[0093] <Examples 3 to 7 and Comparative Examples 1 to 4> A polarizing plate (polarizing plate with adhesive layer) and a product for image display devices were produced in the same manner as in Example 1, except that the type and size of the polarizing plate, the type of adhesive layer, and the formation position of the through-hole were as shown in Table 1. The size L of the adhesive void was adjusted by changing the feed speed, rotation speed, and cutting amount of the drill during end mill processing to form the through-hole. Here, Examples 4 and 6 correspond to the form shown in FIG. 1A, Example 7 corresponds to the form shown in FIG. 1B, and Examples 3 and 5 correspond to the form shown in FIG. 1C. The obtained polarizing plate and product for image display devices were each subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0094] [Table 1]

[0095] As is clear from Table 1, the polarizing plates of the examples of the present invention have a significantly smaller amount of adhesive slippage in the through-hole portion after the heating test than the comparative examples, and delayables are suppressed. [Industrial Applicability]

[0096] The polarizing plate of the present invention can be suitably used in image display devices, and in particular, can be suitably used in image display devices having a camera unit, such as smartphones, tablet PCs, or smart watches. [Explanation of symbols]

[0097] 11 Polarizer 12 Outer protective layer 13 Inner protective layer 20 Adhesive layer 30 Through hole 100 Polarizing Plate

Claims

1. It comprises a polarizer, a protective layer disposed on at least one side of the polarizer, and an adhesive layer. A through hole is formed, Having a rectangular shape, the absorption axis direction of the polarizer is in the direction of the shorter side, and when viewed from above, the through hole is formed at the end in the direction of the longer side and in the center in the direction of the shorter side. The thickness of the polarizer is 15 μm or less. |b １ -b ２ | is 45 mm or less. Polarizing plate: Here, b １ b is the distance from the center of the through hole to one end of the polarizer in the absorption axis direction of the polarizer, and b ２ This is the distance from the center of the through-hole to the other end of the polarizer plate in the absorption axis direction of the polarizer.

2. The polarizing plate according to Claim 1, wherein the diameter R of the through hole is 10 mm or less, and the ratio D / R of the amount of adhesive slippage D to the diameter R of the through hole is 15% or less.

3. The polarizing plate according to claim 1 or 2, wherein the creep value of the adhesive layer is 35 μm / hr to 140 μm / hr: Here, creep value refers to the amount of displacement of the adhesive from the support plate after 1 hour when a 500g load is applied vertically downwards while the adhesive constituting the adhesive layer is attached to the support plate at 85°C and the support plate with the adhesive attached is fixed in place.

4. The polarizing plate according to any one of claims 1 to 3, wherein the polarizing plate has an adhesive void in the through-hole portion such that the end face of the adhesive layer is located inward in the planar direction from the end face of the polarizing plate.

5. comprising an image display cell and a polarizing plate according to any one of claims 1 to 4, The polarizing plate is attached to the image display cell via the adhesive layer. Image display device.

6. A polarizing plate according to any one of claims 1 to 4, another adhesive layer provided on the side of the polarizer of the polarizing plate opposite to the adhesive layer, and a cover glass bonded via the other adhesive layer, The aforementioned through-hole is filled with the adhesive that constitutes the other adhesive layer. The thickness of the polarizer is 15 μm or less. |b1 - b2| is 45 mm or less. Polarizing plate with cover glass: Here, b1 is the distance from the center of the through-hole to one end of the polarizer plate in the direction of the polarizer's absorption axis, and b2 is the distance from the center of the through-hole to the other end of the polarizer plate in the direction of the polarizer's absorption axis.

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