Polarizing plate with phase difference layer and image display device using the same

Abstract

The present invention provides a thin polarizing plate with a phase difference layer, which can suppress the corrosion of metal components when applied to an image display device. The polarizing plate with a phase difference layer of the present invention has a polarizing plate including a polarizer, a phase difference layer and an adhesive layer in order from the visual recognition side. The phase difference layer is an oriented solidified layer of a liquid crystal compound having a circular polarization function or an elliptically polarizing function. The polarizing plate with a phase difference layer is provided with an iodine transmission inhibition layer between the polarizer and the adhesive layer, and the iodine transmission inhibition layer is a solidified product or a thermally cured product of a coating film of an organic solvent solution of a resin; the glass transition temperature of the resin constituting the iodine transmission inhibition layer is above 85°C, and the weight-average molecular weight Mw is above 25,000.

Description

Technical Field

[0001] The present invention relates to a polarizing plate with a phase difference layer and an image display device using the same. Background Art

[0002] In recent years, image display devices represented by liquid crystal display devices and electroluminescent (EL) display devices (such as organic EL display devices and inorganic EL display devices) have become rapidly popular. Image display devices are representative of the use of polarizing plates and phase difference plates. In practical applications, polarizing plates with phase difference layers formed by integrating polarizing plates and phase difference plates are widely used (for example, Patent Document 1). However, recently, as the demand for thinning of image display devices has increased, the demand for thinning of polarizing plates with phase difference layers has also increased. For the purpose of thinning of polarizing plates with phase difference layers, the thinning (or omission) of protective layers of polarizers that have a large impact on thickness and the thinning of phase difference films have been promoted. However, when a thin polarizing plate with a phase difference layer is applied to an image display device, there is a case where metal components (such as electrodes, sensors, wiring, metal layers) of the image display device are corroded. The corrosion of such metal components is significant under high temperature and high humidity environments.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 3325560 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] The present invention is made to solve the above-mentioned conventional problems, and its main object is to provide a thin polarizing plate with a retardation layer, which can suppress corrosion of metal components when used in an image display device.

[0008] Solutions for solving problems

[0009] The polarizing plate with a retardation layer of the present invention comprises, in order from the viewing side, a polarizing plate including a polarizer, a retardation layer, and an adhesive layer. The retardation layer is an aligned and solidified layer of a liquid crystal compound having circular or elliptically polarizing function. An iodine transmission suppression layer is provided between the polarizer and the adhesive layer. The iodine transmission suppression layer is a solidified or thermally cured coating of a resin solution in an organic solvent. The resin constituting the iodine transmission suppression layer has a glass transition temperature of 85°C or higher and a weight-average molecular weight (Mw) of 25,000 or higher.

[0010] In one embodiment, the iodine transmission suppression layer is disposed between the polarizer and the retardation layer. In another embodiment, the iodine transmission suppression layer is disposed between the retardation layer and the adhesive layer.

[0011] In one embodiment, two or more iodine transmission suppression layers are provided between the polarizer and the adhesive layer.

[0012] In one embodiment, the iodine transmission suppression layer has a thickness of 0.05 μm to 10 μm.

[0013] In one embodiment, the glass transition temperature of the resin constituting the iodine transmission suppression layer is 90° C. or higher.

[0014] In one embodiment, the resin constituting the iodine transmission inhibition layer comprises a copolymer obtained by polymerizing a monomer mixture, wherein the monomer mixture comprises greater than 50 parts by weight of a (meth)acrylic acid monomer and greater than 0 parts by weight and less than 50 parts by weight of a monomer represented by formula (1):

[0015]

[0016] (wherein, X represents a functional group containing a reactive group, and the reactive group is at least one reactive group selected from the group consisting of a vinyl group, a (meth)acryloyl group, a styryl group, a (meth)acrylamide group, a vinyl ether group, an epoxy group, an oxetane group, a hydroxyl group, an amino group, an aldehyde group, and a carboxyl group, and R 1 and R 2 Each independently represents a hydrogen atom, an aliphatic hydrocarbon group which may have a substituent, an aryl group which may have a substituent, or a heterocyclic group which may have a substituent, and R 1 and R 2 are optionally linked to each other to form a ring).

[0017] In one embodiment, the retardation layer is a single layer, and Re(550) of the retardation layer is 100nm-190nm. The angle formed by the slow axis of the retardation layer and the absorption axis of the polarizer is 40°-50°.

[0018] In one embodiment, the phase difference layer has a stacked structure of an orientation solidified layer of a first liquid crystal compound and an orientation solidified layer of a second liquid crystal compound; the Re(550) of the orientation solidified layer of the first liquid crystal compound is 200nm~300nm, and the angle formed by its slow axis and the absorption axis of the polarizer is 10°~20°; the Re(550) of the orientation solidified layer of the second liquid crystal compound is 100nm~190nm, and the angle formed by its slow axis and the absorption axis of the polarizer is 70°~80°.

[0019] In one embodiment, the polarizing plate with a retardation layer further comprises another retardation layer between the retardation layer and the adhesive layer, and the refractive index characteristics of the other retardation layer show a relationship of nz>nx=ny.

[0020] In one embodiment, the polarizing plate with a retardation layer further includes a conductive layer or an isotropic substrate with a conductive layer between the iodine transmission suppression layer and the adhesive layer.

[0021] In one embodiment, the total thickness of the polarizing plate with a retardation layer is 60 μm or less.

[0022] According to another aspect of the present invention, there is provided an image display device including the polarizing plate with a retardation layer.

[0023] In one embodiment, the image display device is an organic electroluminescent display device or an inorganic electroluminescent display device.

[0024] Effects of the Invention

[0025] According to an embodiment of the present invention, by providing a specific iodine transmission suppression layer at a predetermined position on a thin polarizing plate with a retardation layer, corrosion of metal components can be suppressed when the polarizing plate with a retardation layer is used in an image display device. The iodine transmission suppression layer that can be used in embodiments of the present invention is a solidified or thermally cured coating of a resin solution in an organic solvent. The resin constituting the iodine transmission suppression layer has a glass transition temperature of 85°C or higher and a weight-average molecular weight (Mw) of 25,000 or higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1A This is a schematic cross-sectional view of a polarizing plate with a retardation layer according to one embodiment of the present invention.

[0027] Figure 1B This is a schematic cross-sectional view of a polarizing plate with a retardation layer according to another embodiment of the present invention.

[0028] Figure 2 This is a schematic cross-sectional view of a polarizing plate with a retardation layer according to still another embodiment of the present invention.

[0029] Figure 3 This is a schematic cross-sectional view of a polarizing plate with a retardation layer according to still another embodiment of the present invention.

[0030] Figure 4 This is a schematic cross-sectional view of a polarizing plate with a retardation layer according to still another embodiment of the present invention.

[0031] Figure 5 This is a schematic cross-sectional view of a polarizing plate with a retardation layer according to still another embodiment of the present invention. DETAILED DESCRIPTION

[0032] Although embodiments of the present invention are described below, the present invention is not limited to these embodiments.

[0033] (Definition of terms and symbols)

[0034] The definitions of terms and symbols in this specification are as follows.

[0035] (1) Refractive index (nx, ny, nz)

[0036] “nx” is the refractive index in the direction where the in-plane refractive index reaches a maximum (ie, the slow axis direction), “ny” is the refractive index in the direction orthogonal to the slow axis in the plane (ie, the fast axis direction), and “nz” is the refractive index in the thickness direction.

[0037] (2) In-plane retardation (Re)

[0038] "Re(λ)" is the in-plane retardation measured at 23°C using light of a wavelength of λ nm. For example, "Re(550)" is the in-plane retardation measured at 23°C using light of a wavelength of 550 nm. When the thickness of a layer (thin film) is d (nm), Re(λ) is calculated using the formula: Re(λ) = (nx - ny) × d.

[0039] (3) Retardation in the thickness direction (Rth)

[0040] "Rth(λ)" is the retardation in the thickness direction measured at 23°C using light of a wavelength of λ nm. For example, "Rth(550)" is the retardation in the thickness direction measured at 23°C using light of a wavelength of 550 nm. When the thickness of a layer (film) is d (nm), Rth(λ) is calculated using the formula: Rth(λ) = (nx - nz) × d.

[0041] (4) Nz coefficient

[0042] The Nz coefficient can be obtained by Nz=Rth / Re.

[0043] (5) Angle

[0044] When an angle is mentioned in this specification, the angle includes both clockwise and counterclockwise directions relative to a reference direction. Therefore, for example, "45°" means ±45°.

[0045] A. Overall structure of polarizing plate with phase difference layer

[0046] Figure 1A Schematic cross-sectional view of a polarizing plate with a phase difference layer according to one embodiment of the present invention; Figure 1B This is a schematic cross-sectional view of a polarizing plate with a retardation layer according to another embodiment of the present invention. Figure 1A and Figure 1B The polarizing plates 100 and 101 with phase difference layers each have a polarizing plate 10, a phase difference layer 20 and an adhesive layer 30 in order from the visual recognition side. The polarizing plate 10 typically includes a polarizer 11 and a protective layer 12 arranged on the visual recognition side of the polarizer 11. Depending on the purpose, another protective layer (not shown) may also be provided on the side of the polarizer 11 opposite to the visual recognition side (protective layer 12). The phase difference layer 20 is an orientation solidified layer of a liquid crystal compound having a circular polarization function or an elliptically polarizing function (hereinafter sometimes referred to as a liquid crystal orientation solidified layer). The adhesive layer 30 is provided as the outermost layer, and the polarizing plate with a phase difference layer can be attached to an image display device (substantially an image display unit).

[0047] In the embodiment of the present invention, an iodine transmission inhibition layer 40 is provided between the polarizer 11 and the adhesive layer 30. The iodine transmission inhibition layer 40 may be formed as follows: Figure 1A As shown, it is disposed between the polarizer 11 and the phase difference layer 20 (ie, adjacent to the polarizer 11), and can also be as shown. Figure 1B As shown, it is disposed between the phase difference layer 20 and the adhesive layer 30. When the iodine transmission inhibition layer is disposed between the polarizer and the phase difference layer (especially when the iodine transmission inhibition layer is adjacent to the polarizer), it can inhibit the migration of iodine from the polarizer in a high temperature and high humidity environment, which has the advantage of improving reliability. When the iodine transmission inhibition layer is disposed between the phase difference layer and the adhesive layer (especially when the iodine transmission inhibition layer is adjacent to the adhesive layer), it can also simultaneously prevent components other than iodine that may affect metal corrosion (such as residual monomer components in ultraviolet curing adhesives and decomposition products of photoinitiators) from migrating into the adhesive, which has the advantage of further improving the metal corrosion inhibition effect.

[0048] In the polarizing plate with a phase difference layer, two or more iodine transmission inhibition layers (e.g. Figure 4 and Figure 5 ). When the polarizing plate with a retardation layer has two or more iodine transmission suppression layers, corrosion of metal components can be significantly suppressed when the polarizing plate with a retardation layer is applied to an image display device.

[0049] Figure 4 In the polarizing plate with a retardation layer shown, two iodine transmission suppression layers are provided between the polarizer and the adhesive layer. Figure 4 In the example shown, two iodine transmission suppression layers are provided: between the polarizer 11 and the retardation layer 20, and between the retardation layer 20 and the adhesive layer 30. In one embodiment, the iodine transmission suppression layer is provided adjacent to the polarizer. In another embodiment, the iodine transmission suppression layer is provided adjacent to the retardation layer. In this specification, "adjacent" means directly stacked without the aid of an adhesive layer or the like.

[0050] Figure 5In the polarizing plate with phase difference layer shown in FIG, three iodine transmission suppression layers are provided between the polarizer and the adhesive layer. Figure 5 In the example shown, two iodine transmission suppression layers are provided between the polarizer 11 and the retardation layer 20, and one layer is provided between the retardation layer 20 and the adhesive layer 30. Of the two iodine transmission suppression layers between the polarizer 11 and the retardation layer 20, one is provided adjacent to the polarizer, and the other is provided adjacent to the retardation layer.

[0051] In a polarizing plate with a retardation layer, the iodine transmission inhibition layer may be four or more layers (e.g., four, five, or six layers). The greater the number of iodine transmission inhibition layers, the greater the metal corrosion inhibition effect. The number of iodine transmission inhibition layers can be set based on factors such as cost, manufacturing efficiency, and the total thickness of the polarizing plate with a retardation layer.

[0052] The iodine transmission inhibition layer is a solidified product or a thermosetting product of a coating film of an organic solvent solution of a resin. Furthermore, the glass transition temperature (Tg) of the resin constituting the iodine transmission inhibition layer is above 85°C, and the weight-average molecular weight Mw is above 25,000. By arranging such an iodine transmission inhibition layer at a specified position of a polarizing plate with a phase difference layer, when the polarizing plate with a phase difference layer is applied to an image display device, the iodine in the polarizer can be significantly suppressed from moving to the image display device (substantially an image display unit). As a result, the corrosion of metal components (such as electrodes, sensors, wiring, and metal layers) of the image display device can be significantly suppressed. Such an effect is a unique effect of a thin polarizing plate with a phase difference layer (representatively, a polarizing plate with a phase difference layer whose phase difference layer is a liquid crystal orientation solidified layer). That is, the present inventors have newly discovered the following problem: when a thin polarizing plate with a phase difference layer is applied to an image display device, there is a case where the metal components of the image display device are corroded, and it was found that the corrosion of such metal components is caused by iodine due to the presence of iodine in the corroded portion. So repeated research was carried out, and it was found that as a means of preventing iodine from moving to the image display device (essentially the image display unit), the iodine transmission inhibition layer as described above (a solidified layer or a thermally cured layer of a coating film of an organic solvent solution of a resin having specific Tg and Mw) is useful, thereby completing the present invention. That is, such an effect solves a brand-new problem that was previously unknown, and is an unexpected excellent effect. Furthermore, as described later, the iodine transmission inhibition layer can be formed to be very thin, and the protective layer on the opposite side to the visual recognition side can be omitted by providing the iodine transmission inhibition layer. Therefore, through their synergistic effect, it can also contribute to the further thinning of the polarizing plate with phase difference layer.

[0053] like Figure 2As shown, in another embodiment of the polarizing plate 102 with a phase difference layer, another phase difference layer 50 and / or a conductive layer or an isotropic substrate 60 with a conductive layer may also be provided. The other phase difference layer 50 is typically provided between the phase difference 20 and the adhesive layer 30 (i.e., outside the phase difference layer 20). The other phase difference layer is representative of a refractive index characteristic showing the relationship nz>nx=ny. The conductive layer or the isotropic substrate 60 with a conductive layer is typically provided between the iodine transmission inhibition layer 40 and the adhesive layer 30 (i.e., outside the iodine transmission inhibition layer 40). The other phase difference layer 50 and the conductive layer or the isotropic substrate 60 with a conductive layer are typically provided in sequence starting from the phase difference layer 20 side. In the example shown in the figure, an iodine transmission suppression layer 40, a phase difference layer 20, another phase difference layer 50, and an isotropic substrate 60 with a conductive layer are provided in sequence from the visual recognition side, but as long as the other phase difference layer 50 is provided between the phase difference 20 and the adhesive layer 30, and the conductive layer or the isotropic substrate 60 with a conductive layer is provided between the iodine transmission suppression layer 40 and the adhesive layer 30, any appropriate configuration order can be adopted. The other phase difference layer 50 and the conductive layer or the isotropic substrate 60 with a conductive layer are representatively any layers provided as needed, and either or both can be omitted. It should be noted that, for convenience, the phase difference layer 20 is sometimes referred to as the first phase difference layer, and the other phase difference layer 50 is sometimes referred to as the second phase difference layer. When a conductive layer or an isotropic substrate with a conductive layer is provided, the polarizing plate with a phase difference layer can be applied to a so-called embedded touch panel type input display device in which a touch sensor is incorporated between an image display unit (such as an organic EL unit) and a polarizing plate. In the embodiment of the present invention, by providing the conductive layer or the isotropic substrate 60 with a conductive layer on the outer side of the iodine permeation suppression layer 40 , corrosion of the conductive layer can be significantly suppressed.

[0054] As mentioned above, the first phase difference layer 20 is a liquid crystal alignment solidification layer. The first phase difference layer 20 can be Figure 1A 、 Figure 1B and Figure 2 The single layer shown may also have Figure 3 The stacked structure of the first liquid crystal alignment fixed layer 21 and the second liquid crystal alignment fixed layer 22 is shown.

[0055] The above embodiments can be combined appropriately, and changes that are obvious in the industry can be added to the components of the above embodiments. Figure 1B A second phase difference layer 50 and / or a conductive layer or an isotropic substrate 60 with a conductive layer is provided on the polarizing plate 101 with a phase difference layer; Figure 1B The phase difference layer 20 of the polarizing plate 101 with a phase difference layer may also have the following Figure 3 The 2-layer structure shown; Figure 3A second phase difference layer 50 and / or a conductive layer or an isotropic substrate 60 with a conductive layer is provided on the polarizing plate 103 with a phase difference layer; Figure 2 The iodine transmission suppression layer 40 of the polarizing plate 102 with a retardation layer may be provided between the retardation layer 20 and the conductive layer or the isotropic substrate 60 with a conductive layer.

[0056] The polarizing plate with a retardation layer according to an embodiment of the present invention may further include other retardation layers. The optical properties (e.g., refractive index properties, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, and configuration position of the other retardation layers can be appropriately set according to the purpose.

[0057] The polarizing plate with a retardation layer according to the embodiments of the present invention may be in the form of a single sheet or an elongated strip. As used herein, "elongated strip" refers to a shape that is sufficiently long relative to its width, including, for example, a shape that is 10 times or more, preferably 20 times or more, longer than its width. The elongated polarizing plate with a retardation layer may be rolled into a roll.

[0058] The total thickness of the polarizing plate with a phase difference layer is preferably less than 60 μm, more preferably less than 55 μm, further preferably less than 50 μm, and particularly preferably less than 40 μm. The lower limit of the total thickness may be, for example, 28 μm. According to an embodiment of the present invention, such an extremely thin polarizing plate with a phase difference layer can be achieved, and further, even when such an extremely thin polarizing plate with a phase difference layer is applied to an image display device, the corrosion of the metal components (such as electrodes, sensors, wiring, metal layers) of the image display device can be significantly suppressed. In addition, such a polarizing plate with a phase difference layer can have extremely excellent flexibility and bending durability. Therefore, such a polarizing plate with a phase difference layer is particularly suitable for application in curved image display devices and / or bendable or foldable image display devices. It should be noted that the so-called total thickness of the polarizing plate with a phase difference layer refers to the total thickness of the polarizing plate, the phase difference layer (the first phase difference layer and the second phase difference layer when the second phase difference layer exists), the iodine transmission inhibition layer and the adhesive layer or adhesive layer used to stack them (that is, the total thickness of the polarizing plate with a phase difference layer does not include the thickness of the conductive layer or the isotropic substrate 60 with a conductive layer, the adhesive layer 30 and the peeling film that can be temporarily bonded to its surface).

[0059] In practical applications, it is preferred to temporarily adhere a release film to the surface of the adhesive layer 30 until the polarizing plate with a retardation layer is used. By temporarily adhering the release film, a roll of the polarizing plate with a retardation layer can be formed while protecting the adhesive layer.

[0060] The components of the polarizing plate with a retardation layer are described in more detail below. It should be noted that the adhesive layer 30 can adopt a structure well known in the industry, and therefore the detailed description of the adhesive layer structure is omitted.

[0061] B.Polarizing plate

[0062] B-1. Polarizer

[0063] The polarizer is typically composed of a polyvinyl alcohol (PVA) resin film containing a dichroic substance. The thickness of the polarizer is preferably 1 μm to 8 μm, more preferably 1 μm to 7 μm, and even more preferably 2 μm to 5 μm. As long as the thickness of the polarizer is within this range, it can significantly contribute to the thinning of the polarizing plate with a phase difference layer. Furthermore, in a thin polarizing plate with a phase difference layer using such a polarizer, the effect of the present invention is significant.

[0064] The boric acid content of the polarizer is preferably 10% by weight or greater, more preferably 13% to 25% by weight. When the boric acid content of the polarizer is within this range, it can maintain ease of curl adjustment during lamination and effectively suppress curling during heating, while improving the durability of the appearance during heating, thanks to a synergistic effect with the iodine content described later. The boric acid content can be calculated, for example, by a neutralization method using the following formula as the amount of boric acid per unit weight of the polarizer.

[0065]

[0066] The iodine content of the polarizer is preferably 2% by weight or more, more preferably 2% to 10% by weight. When the iodine content of the polarizer is within this range, the synergistic effect with the boric acid content can well maintain the ease of curl adjustment during lamination, well suppress curling during heating, and improve the durability of appearance during heating. In this specification, "iodine content" refers to the amount of total iodine contained in the polarizer (PVA-based resin film). More specifically, in the polarizer, iodine is present in the form of iodide ions (I - ), iodine molecules (I2), polyiodide ions (I3 - 、I5 - ) and other forms, the iodine content in this specification refers to the amount of iodine including all of these forms. The iodine content can be calculated, for example, by the standard curve method of fluorescent X-ray analysis. It should be noted that polyiodide ions exist in the polarizer in the form of PVA-iodine complexes. By forming such a complex, absorption dichroism is exhibited in the wavelength range of visible light. Specifically, the complex of PVA and triiodide ions (PVA·I3 - ) has an absorption peak near 470nm, and the complex of PVA and pentaiodide ion (PVA·I5 -) has an absorption peak near 600 nm. As a result, polyiodide ions can absorb light in a wide range of visible light depending on their form. On the other hand, iodide ions (I - ) has an absorption peak near 230nm and does not substantially interfere with the absorption of visible light. Therefore, the polyiodide ions present in the form of a complex with PVA mainly interfere with the absorption performance of the polarizer.

[0067] The polarizer preferably exhibits absorption dichroism at any wavelength between 380 nm and 780 nm. The single transmittance Ts of the polarizer is preferably between 40% and 48%, more preferably between 41% and 46%. The polarization degree P of the polarizer is preferably greater than 97.0%, more preferably greater than 99.0%, and even more preferably greater than 99.9%. The above-mentioned single transmittance is typically the Y value obtained by measuring with an ultraviolet-visible spectrophotometer and correcting for visual sensitivity. The above-mentioned polarization degree is typically obtained by the following formula based on the parallel transmittance Tp and the orthogonal transmittance Tc obtained by measuring with an ultraviolet-visible spectrophotometer and correcting for visual sensitivity.

[0068] Polarization degree (%) = {(Tp-Tc) / (Tp+Tc)} 1 / 2 ×100

[0069] Polarizers can be typically made using a laminate of two or more layers. As a specific example of a polarizer obtained using a laminate, there can be mentioned a polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer formed by coating the resin substrate. A polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer formed by coating the resin substrate can be made, for example, by the following method: a PVA-based resin solution is applied to a resin substrate and dried to form a PVA-based resin layer on the resin substrate, thereby obtaining a laminate of the resin substrate and the PVA-based resin layer; the laminate is stretched and dyed to make the PVA-based resin layer into a polarizer. Stretching typically includes immersing the laminate in a boric acid aqueous solution and stretching it. Furthermore, as needed, stretching may further include stretching the laminate in the air at a high temperature (for example, above 95°C) before stretching in the boric acid aqueous solution. The resulting resin substrate / polarizer laminate can be used directly (i.e., the resin substrate can be used as a protective layer for the polarizer), or the resin substrate can be peeled off from the resin substrate / polarizer laminate and any appropriate protective layer can be laminated on the peeled surface depending on the intended purpose. Details of such polarizer manufacturing methods are described in, for example, Japanese Patent Application Publication No. 2012-73580 and Japanese Patent No. 6470455. The entire contents of these publications are incorporated herein by reference.

[0070] The manufacturing method of the polarizer typically includes: forming a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin on one side of a long thermoplastic resin substrate to form a laminate; and sequentially subjecting the laminate to an air auxiliary stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment, wherein the drying shrinkage treatment is performed by heating the laminate while conveying it in the longitudinal direction so as to shrink it by more than 2% in the width direction. As a result, a very thin polarizer with excellent optical properties and suppressed uneven optical properties can be provided. That is, by introducing auxiliary stretching, the crystallinity of PVA can be improved even when PVA is coated on the thermoplastic resin, thereby achieving high optical properties. In addition, by simultaneously improving the orientation of PVA in advance, problems such as reduction in orientation or dissolution of PVA when immersed in water in the subsequent dyeing and stretching steps can be prevented, thereby achieving high optical properties. Furthermore, immersing the PVA resin layer in a liquid can suppress the disorder of the polyvinyl alcohol molecules' orientation and the reduction of their orientation compared to a PVA resin layer without a halide. This can improve the optical properties of polarizers obtained through treatments such as dyeing and underwater stretching, where the laminate is immersed in a liquid. Furthermore, shrinking the laminate in the width direction during drying and shrinking can improve optical properties.

[0071] B-2. Protective layer

[0072] The protective layer 12 is formed of any appropriate film that can be used as a protective layer of a polarizer. For specific examples of the material as the main component of the film, cellulose resins such as triacetyl cellulose (TAC), polyesters, polyvinyl alcohols, polycarbonates, polyamides, polyimides, polyethersulfones, polysulfones, polystyrenes, polynorbornenes, polyolefins, (meth) acrylic acid, acetates and other transparent resins can be cited. In addition, thermosetting resins or ultraviolet curing resins such as (meth) acrylic acid, carbamate, (meth) acrylic urethane, epoxy, silicone can also be cited. In addition, for example, glassy polymers such as siloxane polymers can also be cited. In addition, the polymer film described in Japanese Patent Publication No. 2001-343529 (WO01 / 37007) can also be used. As a material for the film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in a side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in a side chain can be used. For example, a resin composition containing an alternating copolymer of isobutylene and N-methylmaleimide and an acrylonitrile-styrene copolymer can be used. The polymer film can be, for example, an extrusion molded product of the above resin composition.

[0073] The polarizing plate with phase difference layer is representatively configured on the visual recognition side of the image display device as described later, and the protective layer 12 is representatively configured on its visual recognition side. Therefore, the protective layer 12 can also be subjected to surface treatments such as hard coating, anti-reflection treatment, anti-adhesion treatment, and anti-glare treatment as needed. Furthermore / or, the protective layer 12 can also be subjected to a treatment for improving the visual recognition when visually recognized through polarized sunglasses (representatively, imparting (elliptical) polarization function and imparting ultra-high phase difference) as needed. By implementing such a treatment, even when visually identifying the display screen through polarized lenses such as polarized sunglasses, excellent visual recognition can still be achieved. Therefore, the polarizing plate with phase difference layer can also be suitable for use in image display devices that can be used outdoors.

[0074] The thickness of the protective layer is preferably 10 μm to 50 μm, more preferably 10 μm to 30 μm. When surface treatment is performed, the thickness of the outer protective layer includes the thickness of the surface treatment layer.

[0075] C. 1st phase difference layer

[0076] The first phase difference layer 20 is a liquid crystal orientation solidification layer as described above. By using a liquid crystal compound, the difference between nx and ny of the obtained phase difference layer can be made significantly larger than that of a non-liquid crystal material, so that the thickness of the phase difference layer used to obtain the desired in-plane phase difference can be made significantly smaller. As a result, a further thinning of the polarizing plate with a phase difference layer can be achieved. In this specification, the so-called "liquid crystal orientation solidification layer" refers to a layer in which the liquid crystal compound is oriented in a prescribed direction within the layer and its orientation state is fixed. It should be noted that the "orientation solidification layer" is a concept of an orientation solidification layer obtained by solidifying a liquid crystal monomer as described later. In the present embodiment, a representative state is that the rod-shaped liquid crystal compound is oriented (parallel orientation) in a state of being arranged along the slow axis direction of the first phase difference layer.

[0077] Examples of liquid crystal compounds include those having a nematic phase (nematic liquid crystals). Examples of such liquid crystal compounds include liquid crystal polymers and liquid crystal monomers. The liquid crystal properties of liquid crystal compounds can be expressed by either lyotropic or thermotropic mechanisms. Liquid crystal polymers and liquid crystal monomers can be used alone or in combination.

[0078] When the liquid crystal compound is a liquid crystal monomer, the liquid crystal monomer is preferably a polymerizable monomer and a cross-linking monomer. This is because the orientation state of the liquid crystal monomer can be fixed by polymerizing or cross-linking (i.e., curing) the liquid crystal monomer. After the liquid crystal monomer is oriented, for example, when the liquid crystal monomers are polymerized or cross-linked with each other, the above-mentioned orientation state can be fixed. Here, the polymer is formed by polymerization, and the three-dimensional network structure is formed by cross-linking, but these are non-liquid crystal. Therefore, the first phase difference layer formed will not, for example, undergo the transformation into a liquid crystal phase, a glass phase, or a crystalline phase due to temperature changes that is unique to liquid crystal compounds. As a result, the first phase difference layer becomes a phase difference layer that is not affected by temperature changes and has extremely excellent stability.

[0079] The temperature range in which the liquid crystal monomer exhibits liquid crystallinity varies depending on the type of the liquid crystal monomer, but specifically, the temperature range is preferably 40°C to 120°C, more preferably 50°C to 100°C, and most preferably 60°C to 90°C.

[0080] As the liquid crystal monomer, any appropriate liquid crystal monomer can be used. For example, the polymerizable liquid crystal original compounds described in Japanese Patent Application Publication No. 2002-533742 (WO00 / 37585), EP358208 (US5211877), EP66137 (US4388453), WO93 / 22397, EP0261712, DE19504224, DE4408171 and GB2280445 can be used. As specific examples of such polymerizable liquid crystal original compounds, for example, BASF's trade name LC242, Merck's trade name E7, and Wacker-Chem's trade name LC-Sillicon-CC3767 can be cited. As the liquid crystal monomer, for example, a nematic liquid crystal monomer is preferably used.

[0081] The liquid crystal alignment solidified layer can be formed by subjecting the surface of a predetermined substrate to an orientation treatment, applying a coating solution containing a liquid crystal compound to the surface to align the liquid crystal compound in a direction corresponding to the orientation treatment, and fixing the orientation state. In one embodiment, the substrate is any suitable resin film, and the liquid crystal alignment solidified layer formed on the substrate can be transferred to the surface of an adjacent layer (e.g., a polarizer or an iodine transmission suppression layer).

[0082] As the above-mentioned orientation treatment, any appropriate orientation treatment can be adopted. Specifically, mechanical orientation treatment, physical orientation treatment, and chemical orientation treatment can be mentioned. Specific examples of mechanical orientation treatment include friction treatment and stretching treatment. Specific examples of physical orientation treatment include magnetic field orientation treatment and electric field orientation treatment. Specific examples of chemical orientation treatment include oblique evaporation and optical orientation treatment. The treatment conditions of the various orientation treatments can be any appropriate conditions according to the purpose.

[0083] The alignment of the liquid crystal compound can be carried out by treatment at a temperature at which the liquid crystal phase is exhibited, depending on the type of the liquid crystal compound. By performing such a temperature treatment, the liquid crystal compound becomes a liquid crystal state, and the liquid crystal compound aligns corresponding to the alignment treatment direction of the substrate surface.

[0084] In one embodiment, the fixation of the alignment state is carried out by cooling the liquid crystal compound that has been aligned as described above. When the liquid crystal compound is a polymerizable monomer or a crosslinkable monomer, the fixation of the alignment state is carried out by performing a polymerization treatment or a crosslinking treatment on the liquid crystal compound that has been aligned as described above.

[0085] Specific examples of the liquid crystal compound and details of the method for forming the alignment curing layer are described in Japanese Patent Application Laid-Open No. 2006-163343. The description of this publication is incorporated herein by reference.

[0086] In one embodiment, the first retardation layer 20 is a single layer as Figure 1A , Figure 1B and Figure 2 shown. When the first retardation layer 20 is composed of a single layer, its thickness is preferably 0.5 μm to 7 μm, more preferably 1 μm to 5 μm. By using a liquid crystal compound, an in-plane retardation equivalent to that of a resin film can be achieved at a thickness significantly thinner than that of the resin film.

[0087] The first retardation layer has a circular polarization function or an elliptical polarization function as described above. Typically, the refractive index characteristics of the first retardation layer show a relationship of nx > ny = nz. Typically, the first retardation layer is provided to impart an antireflection property to the polarizing plate, and when the first retardation layer is a single layer, it can function as a λ / 4 plate. At this time, the in-plane retardation Re(550) of the first retardation layer is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, and further preferably 130 nm to 160 nm. Note that here, "ny = nz" includes not only the case where ny and nz are exactly equal but also the case where they are substantially equal. Therefore, there may be cases where ny > nz or ny < nz within the range that does not impair the effects of the present invention.

[0088] The Nz coefficient of the first retardation layer is preferably 0.9 to 1.5, more preferably 0.9 to 1.3. By satisfying such a relationship, when the polarizing plate with the obtained retardation layer is used in an image display device, a very excellent reflected hue can be achieved.

[0089] The first phase difference layer can show an anomalous dispersion wavelength characteristic in which the phase difference value increases with the wavelength of the measurement light, can show a normal wavelength dispersion characteristic in which the phase difference value decreases with the wavelength of the measurement light, and can also show a flat wavelength dispersion characteristic in which the phase difference value hardly changes with the wavelength of the measurement light. In one embodiment, the first phase difference layer shows an anomalous dispersion wavelength characteristic. At this time, the Re(450) / Re(550) of the phase difference layer is preferably greater than 0.8 and less than 1, more preferably greater than 0.8 and less than 0.95. If it is such a structure, a very excellent anti-reflection property can be achieved.

[0090] The angle θ formed by the slow axis of the first retardation layer 20 and the absorption axis of the polarizer 11 is preferably 40° to 50°, more preferably 42° to 48°, and even more preferably about 45°. As long as the angle θ is within this range, by forming the first retardation layer into a λ / 4 plate as described above, a polarizing plate with a retardation layer having very excellent circular polarization characteristics (and consequently, very excellent anti-reflection characteristics) can be obtained.

[0091] In another embodiment, the first phase difference layer 20 is as follows Figure 3As shown, it has a stacked structure of a first liquid crystal alignment solidification layer 21 and a second liquid crystal alignment solidification layer 22. In this case, either the first liquid crystal alignment solidification layer 21 or the second liquid crystal alignment solidification layer 22 can function as a λ / 4 plate, and the other can function as a λ / 2 plate. Therefore, the thickness of the first liquid crystal alignment solidification layer 21 and the second liquid crystal alignment solidification layer 22 can be adjusted in a manner to obtain the desired in-plane phase difference of the λ / 4 plate or the λ / 2 plate. For example, when the first liquid crystal alignment solidification layer 21 functions as a λ / 2 plate and the second liquid crystal alignment solidification layer 22 functions as a λ / 4 plate, the thickness of the first liquid crystal alignment solidification layer 21 is, for example, 2.0 μm to 3.0 μm, and the thickness of the second liquid crystal alignment solidification layer 22 is, for example, 1.0 μm to 2.0 μm. At this time, the in-plane phase difference Re(550) of the first liquid crystal orientation solidified layer is preferably 200nm to 300nm, more preferably 230nm to 290nm, and further preferably 250nm to 280nm. The in-plane phase difference Re(550) of the second liquid crystal orientation solidified layer is as described above with respect to a single layer. The angle formed by the slow axis of the first liquid crystal orientation solidified layer and the absorption axis of the polarizer is preferably 10° to 20°, more preferably 12° to 18°, and further preferably about 15°. The angle formed by the slow axis of the second liquid crystal orientation solidified layer and the absorption axis of the polarizer is preferably 70° to 80°, more preferably 72° to 78°, and further preferably about 75°. As long as it is such a structure, characteristics close to the ideal anomalous wavelength dispersion characteristics can be obtained, and as a result, very excellent anti-reflection characteristics can be achieved. The liquid crystal compounds constituting the first liquid crystal orientation solidified layer and the second liquid crystal orientation solidified layer, the formation method of the first liquid crystal orientation solidified layer and the second liquid crystal orientation solidified layer, the optical characteristics, etc. are as described above with respect to a single layer.

[0092] D. Iodine penetration inhibition layer

[0093] As described above, the iodine transmission inhibition layer is a solidified product or a thermosetting product of a coating film of an organic solvent solution of a resin. As long as it is such a structure, the thickness can be made very thin (for example, less than 10 μm). The thickness of the iodine transmission inhibition layer is preferably 0.05 μm to 10 μm, more preferably 0.08 μm to 5 μm, further preferably 0.1 μm to 1 μm, and particularly preferably 0.2 μm to 0.7 μm. Furthermore, as long as it is such a structure, the iodine transmission inhibition layer can be formed directly (that is, without the aid of an adhesive layer or an adhesive layer) on an adjacent layer (such as a polarizer, a phase difference layer). According to an embodiment of the present invention, as described above, the polarizer, the phase difference layer and the iodine transmission inhibition layer are very thin, and the adhesive layer or adhesive for laminating the iodine transmission inhibition layer can be omitted, so the total thickness of the polarizing plate with a phase difference layer can be made extremely thin. And then, because the hygroscopicity and moisture permeability of such iodine through inhibition layer are smaller than the solidified product of the coating film of the aqueous system such as aqueous solution or aqueous dispersion, it has the advantage of excellent humidification durability. As a result, it is possible to realize a polarizing plate with a phase difference layer with excellent durability that can maintain optical properties even under high temperature and high humidity environment. In addition, such iodine through inhibition layer, for example, compared with the cured product of ultraviolet curable resin, can suppress ultraviolet irradiation from causing adverse effects on polarizing plate (polarizer). The iodine through inhibition layer is preferably a solidified product of the coating film of an organic solvent solution of resin. The solidified product has a small shrinkage during film formation compared with the cured product, and does not contain residual monomers, etc., so the deterioration of the film itself can be suppressed and the residual monomers, etc. can be suppressed from causing adverse effects on polarizing plate (polarizer).

[0094] Furthermore, the glass transition temperature (Tg) of the resin constituting the iodine transmission inhibition layer is 85°C or more, and the weight-average molecular weight Mw is 25,000 or more. As long as the Tg and Mw of the resin are within such a range, the synergistic effect of the effect of constituting the iodine transmission inhibition layer with the solidified product or thermosetting product of the coating film of the organic solvent solution of the resin can significantly suppress the movement of iodine in the polarizer to the image display unit even if it is very thin. As a result, when the polarizing plate with a phase difference layer is applied to the image display device, the corrosion of the metal components can be significantly suppressed. The Tg of the resin is preferably 90°C or more, more preferably 100°C or more, further preferably 110°C or more, and particularly preferably 120°C or more. The upper limit of Tg can be, for example, 200°C. In addition, the Mw of the resin is preferably 30,000 or more, more preferably 35,000 or more, and further preferably 40,000 or more. The upper limit of Mw can be, for example, 150,000.

[0095] As the resin constituting the iodine transmission inhibition layer, any appropriate thermoplastic resin or thermosetting resin can be used, as long as it can form a solidified or thermosetting product of a coating film of an organic solvent solution and has the Tg and Mw described above. A thermoplastic resin is preferred. Examples of thermoplastic resins include acrylic resins and epoxy resins. Combinations of acrylic and epoxy resins are also possible. Representative examples of acrylic and epoxy resins that can be used in the iodine transmission inhibition layer are described below.

[0096] Acrylic resins typically contain repeating units derived from (meth)acrylate monomers having a linear or branched structure as main components. In this specification, (meth)acrylic acid refers to acrylic acid and / or methacrylic acid. Acrylic resins may contain repeating units derived from any appropriate comonomer used according to the purpose. As comonomers, for example, carboxyl-containing monomers, hydroxyl-containing monomers, amide-containing monomers, aromatic ring-containing (meth)acrylates, and heterocyclic vinyl monomers can be cited. By appropriately setting the type, quantity, combination, and copolymerization ratio of the monomer units, an acrylic resin having the above-specified Mw can be obtained.

[0097] <Boron-containing acrylic resin>

[0098] In one embodiment, the acrylic resin includes a copolymer (hereinafter sometimes referred to as a boron-containing acrylic resin) obtained by polymerizing a monomer mixture containing more than 50 parts by weight of a (meth)acrylic monomer and more than 0 parts by weight and less than 50 parts by weight of a monomer represented by formula (1) (hereinafter sometimes referred to as a comonomer).

[0099]

[0100] (wherein, X represents a functional group containing a reactive group, and the reactive group is at least one reactive group selected from the group consisting of a vinyl group, a (meth)acryloyl group, a styryl group, a (meth)acrylamide group, a vinyl ether group, an epoxy group, an oxetane group, a hydroxyl group, an amino group, an aldehyde group, and a carboxyl group, and R 1 and R 2 Each independently represents a hydrogen atom, an aliphatic hydrocarbon group which may have a substituent, an aryl group which may have a substituent, or a heterocyclic group which may have a substituent, and R 1 and R 2 are optionally linked to each other to form a ring).

[0101] Boron-containing acrylic resin is representative of the repeating unit shown in the following formula. By polymerizing the monomer mixture of the comonomer and (meth) acrylic monomer shown in formula (1), the boron-containing acrylic resin has a substituent comprising boron in the side chain (for example, the repeating unit of k in the following formula). Thus, when iodine is transmitted through the suppression layer adjacent to the polarizer and configured, the adhesion to the polarizer will be improved. The substituent comprising boron can be continuously (that is, in block form) included in the boron-containing acrylic resin, or can be randomly included in the boron-containing acrylic resin.

[0102]

[0103] (Where R 6 represents an arbitrary functional group, and j and k represent integers greater than 1).

[0104] <(Meth)acrylic Monomer>

[0105] As the (meth)acrylic monomer, any appropriate (meth)acrylic monomer may be used, and examples thereof include (meth)acrylic acid ester monomers having a linear or branched structure and (meth)acrylic acid ester monomers having a cyclic structure.

[0106] Examples of (meth)acrylate monomers having a linear or branched structure include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate. Methyl (meth)acrylate is preferably used. A single (meth)acrylate monomer may be used alone, or two or more may be used in combination.

[0107] Examples of the (meth)acrylate monomer having a cyclic structure include cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, biphenyl (meth)acrylate, o-biphenyloxyethyl (meth)acrylate, o-biphenyloxyethoxyethyl (meth)acrylate, m-biphenyloxyethyl acrylate, and p-biphenyloxyethyl (meth)acrylate. , o-biphenyloxy-2-hydroxypropyl (meth) acrylate, p-biphenyloxy-2-hydroxypropyl (meth) acrylate, m-biphenyloxy-2-hydroxypropyl (meth) acrylate, N-(meth)acryloyloxyethyl-o-biphenyl=carbamate, N-(meth)acryloyloxyethyl-p-biphenyl=carbamate, N-(meth)acryloyloxyethyl-m-biphenyl=carbamate, monomers containing biphenyl such as o-phenylphenol glycidyl ether acrylate, terphenyl (meth) acrylate, o-terphenyloxyethyl (meth) acrylate, etc. It is preferred to use 1-adamantyl (meth) acrylate and dicyclopentanyl (meth) acrylate. By using these monomers, a polymer with a high glass transition temperature can be obtained. These monomers can be used alone or in combination with two or more.

[0108] In addition, a silsesquioxane compound having a (meth)acryloyl group can also be used instead of the above-mentioned (meth)acrylate monomer. By using a silsesquioxane compound, an acrylic polymer with a high glass transition temperature is obtained. Silsesquioxane compounds having various skeleton structures, such as cage structures, ladder structures, and random structures, are known. The silsesquioxane compound may have only one of these structures, or may have two or more. The silsesquioxane compound may be used alone, or two or more may be used in combination.

[0109] As the (meth)acryloyl group-containing silsesquioxane compound, for example, MAC grade and AC grade of the SQ series produced by Toagosei Co., Ltd. can be used. MAC grade is a methacryloyl group-containing silsesquioxane compound, and specific examples thereof include MAC-SQ TM-100, MAC-SQ SI-20, and MAC-SQ HDM. AC grade is an acryl group-containing silsesquioxane compound, and specific examples thereof include AC-SQ TA-100 and AC-SQ SI-20.

[0110] The (meth)acrylic monomer is used in an amount of more than 50 parts by weight based on 100 parts by weight of the monomer mixture.

[0111] <Comonomer>

[0112] As a comonomer, a monomer represented by the above formula (1) is used. By using such a comonomer, a substituent containing boron is introduced into the side chain of the obtained polymer. The comonomer may be used alone or in combination of two or more.

[0113] Examples of the aliphatic hydrocarbon group in the above formula (1) include a linear or branched alkyl group having 1 to 20 carbon atoms, which may optionally have a substituent, a cyclic alkyl group having 3 to 20 carbon atoms, and an alkenyl group having 2 to 20 carbon atoms, which may optionally have a substituent. Examples of the above aryl group include a phenyl group having 6 to 20 carbon atoms, which may optionally have a substituent, and a naphthyl group having 10 to 20 carbon atoms, which may optionally have a substituent. Examples of the heterocyclic group include a 5-membered cyclic group or a 6-membered cyclic group containing at least one heteroatom, which may optionally have a substituent. It should be noted that R 1 and R 2 They are optionally linked to each other to form a ring. 1 and R 2 It is preferably a hydrogen atom or a linear or branched alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom.

[0114] The reactive group contained in the functional group represented by X is at least one selected from the group consisting of a vinyl group, a (meth)acryloyl group, a styryl group, a (meth)acrylamide group, a vinyl ether group, an epoxy group, an oxetane group, a hydroxyl group, an amino group, an aldehyde group, and a carboxyl group. Preferably, the reactive group is a (meth)acryloyl group and / or a (meth)acrylamide group. By having these reactive groups, when the iodine transmission suppression layer is arranged adjacent to the polarizer, the adhesion to the polarizer is further improved.

[0115] In one embodiment, the functional group represented by X is preferably a functional group represented by ZY-. Here, Z represents a functional group containing at least one reactive group selected from the group consisting of a vinyl group, a (meth)acryloyl group, a styryl group, a (meth)acrylamide group, a vinyl ether group, an epoxy group, an oxetane group, a hydroxyl group, an amino group, an aldehyde group, and a carboxyl group, and Y represents a phenylene group or an alkylene group.

[0116] Specifically, the following compounds can be used as the comonomer.

[0117]

[0118] The comonomer is used in an amount greater than 0 parts by weight and less than 50 parts by weight relative to 100 parts by weight of the monomer mixture, preferably greater than 0.01 parts by weight and less than 50 parts by weight, more preferably 0.05 to 20 parts by weight, further preferably 0.1 to 10 parts by weight, and particularly preferably 0.5 to 5 parts by weight.

[0119] <Acrylic resin containing lactone ring, etc.>

[0120] In another embodiment, the acrylic resin comprises repeating units containing a ring structure selected from lactone ring units, glutaric anhydride units, glutarimide units, maleic anhydride units, and maleimide (N-substituted maleimide) units. The repeating units of the acrylic resin may contain only one type of repeating unit containing a ring structure, or may contain two or more types.

[0121] The lactone ring unit is preferably represented by the following general formula (2):

[0122]

[0123] In the general formula (2), R 2 、R 3 and R 4 Each independently represents a hydrogen atom or an organic residue having 1 to 20 carbon atoms. It should be noted that the organic residue may also contain an oxygen atom. The acrylic resin may contain only a single lactone ring unit or may contain R in the above general formula (2). 2 、R 3 and R 4 Various lactone ring units. Acrylic resins having a lactone ring unit are described in, for example, Japanese Patent Application Laid-Open No. 2008-181078, and the description of this publication is incorporated herein by reference.

[0124] The glutarimide unit is preferably represented by the following general formula (3):

[0125]

[0126] In the general formula (3), R 11 and R 12 Each independently represents hydrogen or an alkyl group having 1 to 8 carbon atoms, and R 13 represents an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an aryl group having 6 to 10 carbon atoms. 11 and R 12 are independently hydrogen or methyl, R 13 is hydrogen, methyl, butyl or cyclohexyl. More preferably, R 11 Methyl, R 12 is hydrogen, R 13 The acrylic resin may contain only a single glutarimide unit or may contain R in the above general formula (3). 11 、R 12 and R 13Various glutarimide units. Acrylic resins having glutarimide units are described, for example, in Japanese Patent Application Laid-Open Nos. 2006-309033, 2006-317560, 2006-328334, 2006-337491, 2006-337492, 2006-337493, and 2006-337569, the contents of which are incorporated herein by reference. It should be noted that, with respect to the glutaric anhydride units, in addition to the units represented by R in the general formula (3), 13 Except for the case where the substituted nitrogen atom is an oxygen atom, the above description about the glutarimide unit is applicable.

[0127] The structures of the maleic anhydride unit and the maleimide (N-substituted maleimide) unit are identified by their names, and thus specific descriptions thereof are omitted.

[0128] The content of the repeating units containing a ring structure in the acrylic resin is preferably 1 to 50 mol%, more preferably 10 to 40 mol%, and even more preferably 20 to 30 mol%. The acrylic resin contains repeating units derived from the above-mentioned (meth)acrylic monomer as the main repeating units.

[0129] <Epoxy resin>

[0130] As the epoxy resin, an epoxy resin having an aromatic ring is preferably used. By using an epoxy resin having an aromatic ring as the epoxy resin, when the iodine transmission suppression layer is arranged adjacent to the polarizer, the adhesion to the polarizer can be improved. Furthermore, when the adhesive layer is arranged adjacent to the iodine transmission suppression layer, the anchoring force of the adhesive layer can be improved. As the epoxy resin having an aromatic ring, for example, bisphenol-type epoxy resins such as bisphenol A epoxy resin, bisphenol F epoxy resin, and bisphenol S epoxy resin can be cited; novolac-type epoxy resins such as phenol novolac epoxy resin, cresol novolac epoxy resin, and hydroxybenzaldehyde phenol novolac epoxy resin; glycidyl ether of tetrahydroxyphenylmethane, glycidyl ether of tetrahydroxybenzophenone, epoxidized polyethylene phenol, etc., naphthol-type epoxy resin, naphthalene-type epoxy resin, biphenyl-type epoxy resin, etc. Preferably, bisphenol A epoxy resin, biphenyl epoxy resin, or bisphenol F epoxy resin is used. The epoxy resin may be used alone or in combination of two or more.

[0131] The iodine permeation inhibition layer can be formed by applying an organic solvent solution of the resin as described above to form a coating film, and the coating film is solidified or thermally cured to form. As an organic solvent, any appropriate organic solvent that can dissolve or uniformly disperse an acrylic resin can be used. As a specific example of an organic solvent, ethyl acetate, toluene, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), cyclopentanone, and cyclohexanone can be cited. The resin concentration of the solution is preferably 3 to 20 parts by weight relative to 100 parts by weight of the solvent. As long as it is such a resin concentration, a uniform coating film can be formed.

[0132] The solution can be coated on any appropriate substrate, or on an adjacent layer (such as a polarizer, a phase difference layer). When the solution is applied to the substrate, the solidified substance (iodine sees through the inhibition layer) of the coating film formed on the substrate is transferred to the adjacent layer. When the solution is applied to the adjacent layer, by drying the coating film (solidification), a protective layer is directly formed on the adjacent layer. Preferably, the solution is applied to the adjacent layer, and a protective layer is directly formed on the adjacent layer. As long as it is such a structure, the adhesive layer or adhesive layer required for transfer can be omitted. Therefore, the polarizing plate with phase difference layer can be made thinner. As a coating method for the solution, any appropriate method can be used. As a specific example, roller coating, spin coating, wire rod coating, dip coating, die coating, curtain coating, spray coating, scraper coating (comma coating method, etc.) can be enumerated.

[0133] The iodine transmission inhibition layer can be formed by solidifying or thermally curing the solution coating. The heating temperature for solidification or thermal curing is preferably 100°C or less, more preferably 50°C to 70°C. As long as the heating temperature is within this range, adverse effects on the polarizer can be prevented. The heating time can vary depending on the heating temperature. For example, the heating time can be 1 to 10 minutes.

[0134] The iodine transmission inhibition layer (substantially an organic solvent solution of the above-mentioned resin) may contain any appropriate additives depending on the purpose. Specific examples of additives include ultraviolet absorbers; leveling agents; antioxidants such as hindered phenol-based, phosphorus-based, and sulfur-based antioxidants; stabilizers such as light stabilizers, weather stabilizers, and heat stabilizers; reinforcing materials such as glass fiber and carbon fiber; near-infrared absorbers; flame retardants such as tris(dibromopropyl)phosphate, triallyl phosphate, and antimony oxide; antistatic agents such as anionic, cationic, and nonionic surfactants; colorants such as inorganic pigments, organic pigments, and dyes; organic or inorganic fillers; resin modifiers; organic and inorganic fillers; plasticizers; lubricants; antistatic agents; and flame retardants. The type, quantity, combination, and addition amount of the additives can be appropriately set depending on the purpose.

[0135] E. Second phase difference layer

[0136] As described above, the second phase difference layer can be a so-called positive C-plate whose refractive index characteristics show the relationship of nz>nx=ny. By using a positive C-plate as the second phase difference layer, oblique reflection can be well prevented, and the anti-reflection function can be made wide-viewing. At this time, the phase difference Rth(550) in the thickness direction of the second phase difference layer is preferably -50nm~-300nm, more preferably -70nm~-250nm, further preferably -90nm~-200nm, and particularly preferably -100nm~-180nm. Here, "nx=ny" not only includes the case where nx and ny are strictly equal, but also includes the case where nx and ny are substantially equal. That is, the in-plane phase difference Re(550) of the second phase difference layer can be less than 10nm.

[0137] The second phase difference layer having the refractive index characteristic of nz>nx=ny can be formed by any appropriate material. The second phase difference layer is preferably formed by a thin film containing a liquid crystal material fixed in a homeotropic orientation. The liquid crystal material (liquid crystal compound) that can be homeotropically oriented can be a liquid crystal monomer or a liquid crystal polymer. As a specific example of the liquid crystal compound and the method for forming the phase difference layer, the liquid crystal compound and the method for forming the phase difference layer described in paragraphs

[0020] to

[0028] of Japanese Patent Gazette No. 2002-333642 can be cited. At this time, the thickness of the second phase difference layer is preferably 0.5μm to 10μm, more preferably 0.5μm to 8μm, and further preferably 0.5μm to 5μm.

[0138] F. Conductive layer or isotropic substrate with conductive layer

[0139] The conductive layer can be formed by forming a metal oxide film on any appropriate substrate using any appropriate film forming method (e.g., vacuum evaporation, sputtering, CVD, ion plating, spraying, etc.). Examples of the metal oxide include indium oxide, tin oxide, zinc oxide, indium-tin composite oxide, tin-antimony composite oxide, zinc-aluminum composite oxide, and indium-zinc composite oxide. Among them, indium-tin composite oxide (ITO) is preferred.

[0140] When the conductive layer comprises a metal oxide, the thickness of the conductive layer is preferably 50 nm or less, more preferably 35 nm or less. The lower limit of the thickness of the conductive layer is preferably 10 nm.

[0141] The conductive layer can be transferred from the substrate to the first retardation layer (or, the iodine transmission suppression layer or, when the second retardation layer is present, the second retardation layer) and the conductive layer itself can be used as a constituent layer of the polarizing plate with a retardation layer. Alternatively, the conductive layer can be laminated on the first retardation layer (or, the iodine transmission suppression layer or, when the second retardation layer is present, the second retardation layer) in the form of a laminate with the substrate (substrate with a conductive layer). Preferably, the substrate is optically isotropic. Therefore, the conductive layer can be used as an isotropic substrate with a conductive layer for a polarizing plate with a retardation layer.

[0142] As an optically isotropic substrate (isotropic substrate), any appropriate isotropic substrate can be used. As the material constituting the isotropic substrate, for example, a material having a resin having no conjugated system such as norbornene resin or olefin resin as the main skeleton, a material having a cyclic structure such as a lactone ring or a glutarimide ring in the main chain of an acrylic resin, etc. can be cited. If such a material is used, the phase difference caused by the orientation of the molecular chain can be suppressed to be smaller when forming the isotropic substrate. The thickness of the isotropic substrate is preferably less than 50 μm, more preferably less than 35 μm. The lower limit of the thickness of the isotropic substrate is, for example, 20 μm.

[0143] The conductive layer and / or the conductive layer of the isotropic substrate with a conductive layer can be patterned as needed. Patterning can form conductive portions and insulating portions. As a result, electrodes can be formed. The electrodes can function as touch sensor electrodes for sensing contact with the touch panel. Any appropriate patterning method can be employed. Specific examples of patterning methods include wet etching and screen printing.

[0144] G. Image display device

[0145] The polarizing plate with a phase difference layer described in items A to F above can be applied to an image display device. Therefore, an embodiment of the present invention includes an image display device using such a polarizing plate with a phase difference layer. As representative examples of image display devices, liquid crystal display devices and electroluminescent (EL) display devices (such as organic EL display devices and inorganic EL display devices) can be cited. The image display device of an embodiment of the present invention has a polarizing plate with a phase difference layer described in items A to F above on its visual recognition side. The polarizing plate with a phase difference layer is stacked in such a way that the phase difference layer becomes the side of the image display unit (such as a liquid crystal unit, an organic EL unit, an inorganic EL unit) (the polarizer becomes the visual recognition side). Although such an image display device is very thin, the corrosion of metal components is significantly suppressed. In one embodiment, the image display device has a curved shape (substantially a curved display screen) and / or is bendable or foldable.

[0146] Example

[0147] The present invention is described in detail below using examples, but the present invention is not limited to these examples. The measurement methods of various properties are as follows. In addition, unless otherwise specified, "parts" and "%" in the examples and comparative examples are based on weight.

[0148] (1) Thickness

[0149] Thicknesses of 10 μm or less were measured using an interferometer thickness meter (manufactured by Otsuka Electronics Co., Ltd., product name “MCPD-3000”). Thicknesses greater than 10 μm were measured using a digital micrometer (manufactured by Anritsu Corporation, product name “KC-351C”).

[0150] (2) Metal corrosion (48 hours)

[0151] A silver nanowire solution (manufactured by Merck, nanowire size: 115 nm diameter, 20 to 50 μm length, 0.5% solids in isopropyl alcohol (IPA) solution) was applied to one side of a 50 μm polyethylene terephthalate (PET) film using a wire rod to a wet film thickness of 15 μm. The film was then dried in a 100°C oven for 5 minutes to form a silver nanowire coating. Next, an overcoat solution (solids concentration: approximately 1%) containing 99 parts methyl isobutyl ketone (MIBK), 1 part pentaerythritol tetraacrylate (PETA), and 0.03 parts photopolymerization initiator (manufactured by BASF, product name "IRGACURE 907") was applied to the surface of the silver nanowire coating using a wire rod to a wet film thickness of 10 μm. The film was then dried in a 100°C oven for 5 minutes. Next, the overcoat film was cured by irradiation with active energy rays, producing a metal thin film having a structure consisting of a PET film / silver nanowire layer / overcoat layer (100 nm thick). This metal thin film was bonded to a 0.5 mm thick glass plate using an adhesive (15 μm), resulting in a metal thin film / adhesive / glass plate laminate. The electrical resistance of the resulting laminate was measured using a non-contact resistance meter (manufactured by Napson, product name "EC-80") and found to be 50 Ω / □.

[0152] The polarizing plate with a phase difference layer obtained in the embodiment and the comparative example is attached to the outer coating surface of the metal film of the laminate as a test sample. The resistance value of the test sample is measured by a non-contact resistance meter as the initial resistance value. Furthermore, after the test sample is subjected to a reliability test (placed under an environment of 85°C·85% RH for 48 hours, and then placed under an environment of 23°C·55% RH for 2 hours), the resistance value is measured in the same manner as above. The resistance value increase rate is calculated by the following formula. It should be noted that when the measured value (resistance value) is greater than the measurement limit (1000Ω / □) of the non-contact resistance meter, the measured value is assumed to be 1500Ω / □.

[0153] Resistance value increase rate (%) = {(resistance value after reliability test - initial resistance value) / initial resistance value} × 100

[0154] Furthermore, evaluation was performed based on the following criteria.

[0155] Good: Resistance value increase rate is less than 200%

[0156] Defective: Resistance value increase rate is more than 200%

[0157] (3) Metal corrosion (200 hours)

[0158] The polarizing plate with a phase difference layer obtained in the embodiment and the comparative example is attached to the outer coating forming surface of the metal film of the laminate obtained in (2) as a test sample. The resistance value of the test sample is measured by a non-contact resistance meter as the initial resistance value. Furthermore, after the test sample is subjected to a reliability test (placed in an environment of 85°C·85%RH for 200 hours, and then placed in an environment of 23°C·55%RH for 2 hours), the resistance value is measured in the same manner as above. The resistance value increase rate is calculated by the following formula. It should be noted that when the measured value (resistance value) is greater than the measurement limit (1000Ω / □) of the non-contact resistance meter, the measured value is assumed to be 1500Ω / □.

[0159] Resistance value increase rate (%) = {(resistance value after reliability test - initial resistance value) / initial resistance value} × 100

[0160] Furthermore, evaluation was performed based on the following criteria.

[0161] Excellent: Resistance value increase rate is less than 200%

[0162] Good: Resistance value increase rate is 200% or more and less than 2000%

[0163] Defective: Resistance value increase rate is more than 2000%

[0164] [Example 1]

[0165] 1. Production of polarizers

[0166] As the thermoplastic resin substrate, a long amorphous polyethylene terephthalate copolymer film (thickness: 100 μm) having a water absorption of 0.75% and a Tg of approximately 75° C. was used. One surface of the resin substrate was corona treated.

[0167] 13 parts by weight of potassium iodide was added to 100 parts by weight of a PVA-based resin prepared by mixing polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMER Z410") in a ratio of 9:1, and the resulting product was dissolved in water to prepare a PVA aqueous solution (coating solution).

[0168] The PVA aqueous solution was applied to the corona-treated surface of the resin substrate and dried at 60° C. to form a PVA-based resin layer having a thickness of 13 μm, thereby producing a laminate.

[0169] The obtained laminate was subjected to free-end uniaxial stretching to 2.4 times in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds in an oven at 130° C. (in-air auxiliary stretching treatment).

[0170] Next, the laminate was immersed in an insolubilization bath (boric acid aqueous solution prepared by adding 4 parts by weight of boric acid to 100 parts by weight of water) at a liquid temperature of 40° C. for 30 seconds (insolubilization treatment).

[0171] Next, the polarizer was immersed in a dyeing bath (an iodine aqueous solution obtained by mixing iodine and potassium iodide at a weight ratio of 1:7 per 100 parts by weight of water) at a liquid temperature of 30°C for 60 seconds (dyeing treatment) with a concentration adjusted so that the single-body transmittance (Ts) of the resulting polarizer would be 43.0% or higher.

[0172] Next, the film was immersed in a crosslinking bath (boric acid aqueous solution prepared by adding 3 parts by weight of potassium iodide and 5 parts by weight of boric acid to 100 parts by weight of water) at a liquid temperature of 40° C. for 30 seconds (crosslinking treatment).

[0173] Thereafter, the laminate is immersed in a boric acid aqueous solution (boric acid concentration of 4.0 wt %, potassium iodide concentration of 5 wt %) at a liquid temperature of 70°C and uniaxially stretched (underwater stretching treatment) in the longitudinal direction (length direction) between rollers with different peripheral speeds so that the total stretching ratio becomes 5.5 times.

[0174] Thereafter, the laminate was immersed in a cleaning bath (an aqueous solution prepared by adding 4 parts by weight of potassium iodide to 100 parts by weight of water) at a liquid temperature of 20° C. (cleaning treatment).

[0175] Thereafter, the laminate was dried in an oven maintained at 90° C. while being brought into contact with a SUS heating roll maintained at a surface temperature of 75° C. for about 2 seconds (drying shrinkage treatment). The shrinkage rate of the laminate in the width direction due to the drying shrinkage treatment was 5.2%.

[0176] In this manner, a polarizer having a thickness of 5 μm was formed on the resin substrate.

[0177] 2. Production of polarizing plate

[0178] An HC-COP film is bonded to the surface of the polarizer obtained above (the surface on the opposite side to the resin substrate) as a protective layer with the help of an ultraviolet curing adhesive. Specifically, the coating is performed so that the total thickness of the curing adhesive becomes 1.0 μm, and the bonding is performed using a roller mill. Thereafter, UV light is irradiated from the protective layer side to cure the adhesive. It should be noted that the HC-COP film is a film having a hard coating (HC) layer (thickness 2 μm) formed on a cycloolefin (COP) film (manufactured by ZEON Corporation of Japan, product name "ZF12", thickness 25 μm), and is bonded in such a way that the COP film becomes the polarizer side. Next, the resin substrate is peeled off to obtain a polarizing plate having a structure of protective layer (HC layer / COP film) / adhesive layer / polarizer.

[0179] 3. Preparation of the First and Second Oriented Solidified Layers Constituting the Phase Difference Layer

[0180] 10 g of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (manufactured by BASF: trade name "Paliocolor LC242", represented by the following formula) and 3 g of a photopolymerization initiator for the polymerizable liquid crystal compound (manufactured by BASF: trade name "IRGACURE 907") were dissolved in 40 g of toluene to prepare a liquid crystal composition (coating liquid).

[0181]

[0182] The surface of polyethylene terephthalate (PET) film (thickness 38 μm) was rubbed with a rubbing cloth to perform an orientation treatment. The orientation treatment direction was set to be 15° relative to the absorption axis direction of the polarizer when viewed from the visual recognition side when attached to the polarizing plate. The above-mentioned liquid crystal coating liquid was applied to the orientation treatment surface using a rod coater and heated and dried at 90°C for 2 minutes to orient the liquid crystal compound. A metal halide lamp was used at 1 mJ / cm 2 The liquid crystal layer thus formed was irradiated with light, causing the liquid crystal layer to solidify, thereby forming a liquid crystal alignment solidified layer A on the PET film. The liquid crystal alignment solidified layer A had a thickness of 2.5 μm and an in-plane retardation Re(550) of 270 nm. Furthermore, the liquid crystal alignment solidified layer A had a refractive index distribution of nx>ny=nz.

[0183] A liquid crystal alignment cured layer B 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 be 75° relative to the absorption axis of the polarizer when viewed from the viewing side. The liquid crystal alignment cured layer B had a thickness of 1.5 μm and an in-plane retardation Re(550) of 140 nm. Furthermore, the liquid crystal alignment cured layer B had a refractive index distribution of nx>ny=nz.

[0184] 4. Formation of phase difference layer

[0185] The liquid crystal orientation solidification layer A and the liquid crystal orientation solidification layer B obtained in the above 3. are transferred in sequence to the surface of the polarizer of the polarizing plate obtained in the above 2. At this time, the transfer (lamination) is performed in a manner such that the angle formed by the absorption axis of the polarizer and the slow axis of the liquid crystal orientation solidification layer A is 15° and the angle formed by the absorption axis of the polarizer and the slow axis of the liquid crystal orientation solidification layer B is 75°. It should be noted that each transfer (lamination) is performed with the aid of the ultraviolet curing adhesive (thickness 1.0 μm) used in the above 2. Thus, a laminate having the structure of protective layer (HC layer / COP film) / adhesive layer / polarizer / adhesive layer / phase difference layer (first liquid crystal orientation solidification layer / adhesive layer / second liquid crystal orientation solidification layer) is produced.

[0186] 5. Preparation of polarizing plate with phase difference layer

[0187] 20 parts of an acrylic resin (manufactured by Kusumoto Chemicals Co., Ltd., product name "B-811", Tg: 110°C, Mw: 40,000) were dissolved in 80 parts of methyl ethyl ketone to obtain a resin solution (20%). This resin solution was applied using a wire bar to the surface of the second liquid crystal orientation solidified layer of the laminate obtained in step 4. above, and the coated film was dried at 60°C for 5 minutes to form an iodine transmission inhibition layer (0.5 μm thick) consisting of a solidified product of the coated film of the resin organic solvent solution. Next, an adhesive layer (15 μm thick) was provided on the surface of the iodine transmission inhibition layer to obtain a polarizing plate with a phase difference layer having a structure of protective layer (HC layer / COP film) / adhesive layer / polarizer / adhesive layer / phase difference layer (first liquid crystal orientation solidified layer / adhesive layer / second liquid crystal orientation solidified layer) / iodine transmission inhibition layer / adhesive layer. The total thickness of the resulting polarizing plate with a phase difference layer was 39.5 μm. The obtained polarizing plate with a retardation layer was subjected to the evaluations of (2) and (3) above. Furthermore, metal corrosion resistance was compared with Comparative Example 1 (described later) in which no iodine transmission suppression layer was formed. The results are shown in Tables 1 and 2.

[0188] [Example 2]

[0189] 97.0 parts of methyl methacrylate (MMA, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "methyl methacrylate monomer"), 3.0 parts of the comonomer represented by the above general formula (1e), and 0.2 parts of a polymerization initiator (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "2,2'-azobis(isobutyronitrile)") were dissolved in 200 parts of toluene. Subsequently, a polymerization reaction was carried out for 5.5 hours while heating to 70°C under a nitrogen atmosphere to obtain a boron-containing acrylic resin solution (solid content concentration: 33%). The Tg of the obtained boron-containing acrylic polymer was 110°C and the Mw was 80,000. A polarizing plate with a phase difference layer was prepared in the same manner as in Example 1 except that the boron-containing acrylic polymer was used instead of the acrylic resin "B-811" and the thickness of the iodine transmission suppression layer was set to 0.3 μm. The obtained polarizing plate with a phase difference layer was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

[0190] [Example 3]

[0191] A polarizing plate with a retardation layer was produced in the same manner as in Example 2 except that the thickness of the iodine transmission suppression layer was changed to 0.5 μm. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

[0192] [Example 4]

[0193] A polarizing plate with a retardation layer was prepared in the same manner as in Example 1, except that a thermoplastic epoxy resin (manufactured by Mitsubishi Chemical Co., trade name "jER (registered trademark) 1256B40," Tg: 100°C, Mw: 45,000) was used instead of the acrylic resin "B-811." The resulting polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

[0194] [Example 5]

[0195] A polarizing plate with a retardation layer was prepared in the same manner as in Example 1, except that a thermoplastic epoxy resin (manufactured by Mitsubishi Chemical Co., trade name "jER (registered trademark) YX7200B35," Tg: 150°C, Mw: 30,000) was used instead of the acrylic resin "B-811" and the thickness of the iodine transmission suppression layer was changed to 0.3 μm. The resulting polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

[0196] [Example 6]

[0197] A polarizing plate with a retardation layer was produced in the same manner as in Example 5 except that the thickness of the iodine transmission suppression layer was changed to 0.5 μm. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

[0198] [Example 7]

[0199] A polarizing plate with a retardation layer was produced in the same manner as in Example 1, except that a blend of 15 parts of "B-811" and 85 parts (based on solid content) of a thermoplastic epoxy resin (manufactured by Mitsubishi Chemical Co., trade name "jER (registered trademark) YX6954BH30") was used instead of the acrylic resin "B-811." The blend had a Tg of 125°C and an Mw of 38,000. The resulting polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

[0200] [Example 8]

[0201] The polarizer side of the polarizing plate having the structure of a protective layer (HC layer / COP film) / adhesive layer / polarizer obtained in 2. of Example 1 is coated with the resin blend used in Example 7 and dried to form an iodine transmission inhibition layer (thickness 0.5 μm) in the form of a solidified coating film of an organic solvent solution of the resin. The liquid crystal orientation solidified layer A and the liquid crystal orientation solidified layer B are sequentially transferred to the surface of the iodine transmission inhibition layer in the same manner as in Example 1 to obtain a polarizing plate with a phase difference layer having the structure of a protective layer (HC layer / COP film) / adhesive layer / polarizer / iodine transmission inhibition layer / adhesive layer / phase difference layer (first liquid crystal orientation solidified layer / adhesive layer / second liquid crystal orientation solidified layer) / adhesive layer. The obtained polarizing plate with a phase difference layer is subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

[0202] [Example 9]

[0203] In addition to using the boron-containing acrylic polymer in Example 2, a laminate having a structure of a protective layer (HC layer / COP film) / adhesive layer / polarizer / iodine transmission inhibition layer was prepared in the same manner as in Example 8. Next, a blend of 15 parts of the boron-containing acrylic polymer in Example 2 and 85 parts (solid content conversion) of a thermoplastic epoxy resin (manufactured by Mitsubishi Chemical Co., trade name "jER (registered trademark) YX6954BH30") was used. In addition, a polarizing plate with a phase difference layer having a structure of a protective layer (HC layer / COP film) / adhesive layer / polarizer / iodine transmission inhibition layer / adhesive layer / phase difference layer (first liquid crystal orientation solidified layer / adhesive layer / second liquid crystal orientation solidified layer) / iodine transmission inhibition layer / adhesive layer was obtained in the same manner as in Example 1. The total thickness of the obtained polarizing plate with a phase difference layer was 40 μm. The obtained polarizing plate with a phase difference layer was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

[0204] [Example 10]

[0205] The iodine transmission suppression layer provided between the polarizer and the phase difference layer and adjacent to the polarizer is a blend of 15 parts of the boron-containing acrylic polymer obtained in Example 2 and 85 parts of a thermoplastic epoxy resin (Mitsubishi Chemical Co., trade name "jER (registered trademark) YX6954BH30") (solid content conversion). A polarizing plate with a phase difference layer is obtained in the same manner as in Example 9. The total thickness of the obtained polarizing plate with a phase difference layer is 40 μm. The obtained polarizing plate with a phase difference layer is subjected to the same evaluation as in Example 1. The results are shown in Table 2.

[0206] [Example 11]

[0207] The iodine transmission inhibition layer formed between the polarizer and the phase difference layer and adjacent to the polarizer is formed between the polarizer and the phase difference layer and adjacent to the phase difference layer. In addition, the same method as in Example 10 is used to obtain a polarizing plate with a phase difference layer having a protective layer (HC layer / COP film) / adhesive layer / polarizer / adhesive layer / iodine transmission inhibition layer / phase difference layer (1st liquid crystal orientation solidified layer / adhesive layer / 2nd liquid crystal orientation solidified layer) / iodine transmission inhibition layer / adhesive layer. The total thickness of the obtained polarizing plate with a phase difference layer is 40 μm. The obtained polarizing plate with a phase difference layer is subjected to the same evaluation as in Example 1. The results are shown in Table 2.

[0208] [Example 12]

[0209] The same operation as in Example 9 was performed, and an iodine transmission inhibition layer was further formed between the polarizer and the phase difference layer and at a position adjacent to the polarizer. In addition, a polarizing plate with a phase difference layer having a structure of a protective layer (HC layer / COP film) / adhesive layer / polarizer / iodine transmission inhibition layer / adhesive layer / iodine transmission inhibition layer / phase difference layer (first liquid crystal orientation solidified layer / adhesive layer / second liquid crystal orientation solidified layer) / iodine transmission inhibition layer / adhesive layer was obtained in the same manner as in Example 11. The total thickness of the polarizing plate with a phase difference layer obtained was 40.5 μm. The polarizing plate with a phase difference layer obtained was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

[0210] [Comparative Example 1]

[0211] A polarizing plate with a retardation layer was produced in the same manner as in Example 1 except that the iodine transmission suppression layer was not formed. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

[0212] [Comparative Example 2]

[0213] A polarizing plate with a retardation layer was produced in the same manner as in Example 1, except that acrylic resin "B-723" (manufactured by Kusumoto Chemicals, Tg: 54°C, Mw: 200,000) was used instead of acrylic resin "B-811." The resulting polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

[0214] [Comparative Example 3]

[0215] A polarizing plate with a retardation layer was produced in the same manner as in Example 1, except that a photocurable epoxy resin (trade name "jER (registered trademark) 828" manufactured by Mitsubishi Chemical Co., Ltd.) was used instead of the acrylic resin "B-811" and "CPI100P" manufactured by San-Apro Ltd.) was used as the photopolymerization initiator. The resulting polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

[0216] [Comparative Example 4]

[0217] A polarizing plate with a retardation layer was produced in the same manner as in Example 1, except that a PVA resin (manufactured by Mitsubishi Chemical Co., trade name "GOHSENOL Z200," Tg: 80°C, Mw: 8800) was used instead of the acrylic resin "B-811." The resulting polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

[0218] [Reference Example 1]

[0219] 1. Production of polarizing plate

[0220] A polarizing plate having a structure of protective layer (HC layer / COP film) / polarizer was obtained in the same manner as in Example 1.

[0221] 2. Preparation of the phase difference film constituting the phase difference layer

[0222] 2-1. Polymerization of polyester carbonate resin

[0223] The polymerization was carried out using a batch polymerization apparatus consisting of two vertical reactors equipped with stirring blades and reflux condensers controlled at 100° C. 29.60 parts by mass (0.046 mol) of bis[9-(2-phenoxycarbonylethyl)fluoren-9-yl]methane, 29.21 parts by mass (0.200 mol) of isosorbide (ISB), 42.28 parts by mass (0.139 mol) of spiroglycol (SPG), 63.77 parts by mass (0.298 mol) of diphenyl carbonate (DPC), and 1.19×10 mol of calcium acetate monohydrate as a catalyst were added. -2 Mass parts (6.78×10 -5 mol). After the reactor was purged with nitrogen, it was heated with a heat medium and stirring began when the internal temperature reached 100°C. 40 minutes after the start of the temperature increase, the internal temperature reached 220°C and was maintained at this temperature while simultaneously reducing the pressure until it reached 13.3 kPa 90 minutes after reaching 220°C. Phenol vapor, a by-product of the polymerization reaction, was introduced into a 100°C reflux condenser to return a small amount of monomer components contained in the phenol vapor to the reactor. Uncondensed phenol vapor was recovered by introducing nitrogen into a 45°C condenser. Nitrogen was introduced into the first reactor to temporarily return it to atmospheric pressure, and the oligomerized reaction liquid in the first reactor was transferred to the second reactor. Next, the temperature and pressure reduction in the second reactor were initiated, reaching an internal temperature of 240°C and a pressure of 0.2 kPa after 50 minutes. Polymerization was then continued until the specified stirring power was reached. When the predetermined power was reached, nitrogen gas was introduced into the reactor to restore the pressure, and the produced polyester carbonate resin was extruded into water, and the strands were cut to obtain pellets.

[0224] 2-2. Preparation of Phase Difference Film

[0225] The obtained polyester carbonate resin (pellets) was vacuum dried at 80°C for 5 hours, and then a film forming device equipped with a single screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder set temperature: 250°C), a T-die (width 200 mm, set temperature: 250°C), a cooling roller (set temperature: 120-130°C) and a winder was used to prepare a long strip of resin film with a thickness of 135 μm. The obtained long strip of resin film was stretched in the width direction at a stretching temperature of 133°C and a stretching ratio of 2.8 times to obtain a retardation film with a thickness of 53 μm. The Re(550) of the obtained retardation film was 141 nm, Re(450) / Re(550) was 0.82, and the Nz coefficient was 1.12.

[0226] 3. Preparation of polarizing plate with phase difference layer

[0227] The phase difference film obtained in 2. is adhered to the surface of the polarizer of the polarizing plate obtained in 1. above with the help of an acrylic adhesive (thickness 5 μm). At this time, the absorption axis of the polarizer is adhered to the slow axis of the phase difference film in a manner that forms an angle of 45°. Furthermore, an adhesive layer the same as in Example 1 is provided on the surface of the phase difference layer. Thus, a polarizing plate with a phase difference layer having a structure of a protective layer / adhesive layer / polarizer / adhesive layer / phase difference layer (stretched film of resin film) / adhesive layer is obtained. The total thickness of the obtained polarizing plate with a phase difference layer is 91 μm. The obtained polarizing plate with a phase difference layer is subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2.

[0228] [Table 1]

[0229]

[0230] *The blend is a blend of acrylic resin and epoxy resin

[0231] * Position A indicates the area between the phase difference layer and the adhesive layer, and position B indicates the area between the polarizer and the phase difference layer.

[0232] [Table 2]

[0233]

[0234] *The blend is a blend of acrylic resin and epoxy resin

[0235] * Position A indicates the position between the phase difference layer and the adhesive layer, Position B indicates the position between the polarizer and the phase difference layer and adjacent to the polarizer, and Position C indicates the position between the polarizer and the phase difference layer and adjacent to the phase difference layer.

[0236] [evaluate]

[0237] As is clear from Table 1, the polarizing plates with retardation layers of the examples of the present invention significantly suppress metal corrosion in high-temperature, high-humidity environments by forming an iodine transmission suppression layer composed of a solidified product of a coating of an organic solvent solution of a resin having a predetermined Tg and Mw. Therefore, it is clear that the polarizing plates with retardation layers of the examples of the present invention can suppress corrosion of metal components when used in image display devices. Furthermore, as is clear from Reference Example 1, such metal corrosion is a unique issue for very thin polarizing plates with retardation layers.

[0238] As shown in Table 2, the polarizing plates with retardation layers of Examples 9 to 12 of the present invention, by including two or three iodine transmission suppression layers, can significantly suppress metal corrosion even when exposed to high temperature and high humidity for a long period of time (200 hours). Therefore, it can be seen that the polarizing plates with retardation layers of Examples 9 to 12 of the present invention can significantly suppress corrosion of metal components when used in image display devices.

[0239] Industrial applicability

[0240] The polarizing plate with a retardation layer of the present invention can be suitably used as a circularly polarizing plate for liquid crystal display devices, organic EL display devices, and inorganic EL display devices.

[0241] Description of Reference Numerals

[0242] 10: Polarizing plate

[0243] 11: Polarizer

[0244] 12: Protective layer

[0245] 20: Phase difference layer

[0246] 30: Adhesive layer

[0247] 40: Iodine penetration inhibition layer

[0248] 100: Polarizing plate with phase difference layer

[0249] 101: Polarizing plate with phase difference layer

[0250] 102: Polarizing plate with phase difference layer

[0251] 103: Polarizing plate with phase difference layer

[0252] 104: Polarizing plate with phase difference layer

[0253] 105: Polarizing plate with phase difference layer

Claims

1. A polarizing plate with a phase difference layer, comprising, in order from the visual recognition side, a polarizing plate including a polarizer, a phase difference layer, and an adhesive layer; The phase difference layer is an orientation solidified layer of a liquid crystal compound having a circular polarization function or an elliptically polarization function; An iodine transmission inhibition layer is provided between the polarizer and the adhesive layer. The iodine transmission inhibition layer is a solidified product or a thermosetting product of a coating film of an organic solvent solution of a resin. The iodine transmission inhibition layer is composed of a thermoplastic resin that is soluble in an organic solvent. The resin constituting the iodine transmission suppression layer has a glass transition temperature of 85° C. or higher and a weight average molecular weight Mw of 25,000 or higher.

2. The polarizing plate with a phase difference layer according to claim 1, wherein: The iodine transmission inhibition layer is disposed between the polarizer and the phase difference layer.

3. The polarizing plate with a phase difference layer according to claim 1, wherein: The iodine transmission suppression layer is provided between the phase difference layer and the adhesive layer.

4. The polarizing plate with a phase difference layer according to claim 1, wherein: The iodine transmission suppression layer is provided in two or more layers between the polarizer and the adhesive layer.

5. The polarizing plate with a phase difference layer according to any one of claims 1 to 4, wherein The thickness of the iodine transmission inhibition layer is 0.05 μm to 10 μm.

6. The polarizing plate with a phase difference layer according to any one of claims 1 to 4, wherein The glass transition temperature of the resin constituting the iodine transmission suppression layer is 90° C. or higher.

7. The polarizing plate with a phase difference layer according to any one of claims 1 to 4, wherein The resin constituting the iodine transmission inhibition layer comprises a copolymer obtained by polymerizing a monomer mixture, wherein the monomer mixture comprises greater than 50 parts by weight of a (meth)acrylic acid monomer and greater than 0 parts by weight and less than 50 parts by weight of a monomer represented by formula (1). In the formula, X represents a functional group containing a reactive group, and the reactive group is at least one reactive group selected from the group consisting of a vinyl group, a (meth)acryloyl group, a styryl group, a (meth)acrylamide group, a vinyl ether group, an epoxy group, an oxetane group, a hydroxyl group, an amino group, an aldehyde group, and a carboxyl group, and R 1 and R 2 Each independently represents a hydrogen atom, an aliphatic hydrocarbon group which may have a substituent, an aryl group which may have a substituent, or a heterocyclic group which may have a substituent, and R 1 and R 2 They are optionally linked to each other to form a ring.

8. The polarizing plate with a phase difference layer according to any one of claims 1 to 4, wherein The phase difference layer is a single layer, The Re(550) of the phase difference layer is 100nm~190nm, The angle formed by the slow axis of the phase difference layer and the absorption axis of the polarizer is 40° to 50°.

9. The polarizing plate with a phase difference layer according to any one of claims 1 to 4, wherein The phase difference layer has a stacked structure of an alignment solidified layer of a first liquid crystal compound and an alignment solidified layer of a second liquid crystal compound; The Re(550) of the alignment solidified layer of the first liquid crystal compound is 200 nm to 300 nm, and the angle formed by the slow axis thereof and the absorption axis of the polarizer is 10° to 20°; The Re(550) of the alignment solidified layer of the second liquid crystal compound is 100 nm to 190 nm, and the angle formed by the slow axis thereof and the absorption axis of the polarizer is 70° to 80°.

10. The polarizing plate with a phase difference layer according to any one of claims 1 to 4, wherein Another phase difference layer is provided between the phase difference layer and the adhesive layer, and the refractive index characteristics of the other phase difference layer show the relationship of nz>nx=ny.

11. The polarizing plate with a phase difference layer according to any one of claims 1 to 4, wherein A conductive layer or an isotropic substrate with a conductive layer is further provided between the iodine permeation suppression layer and the adhesive layer. 12 . The polarizing plate with a retardation layer according to claim 1 , wherein the total thickness is 60 μm or less. 13 . An image display device comprising the polarizing plate with a retardation layer according to claim 1 . 14 . The image display device according to claim 13 , which is an organic electroluminescent display device or an inorganic electroluminescent display device.

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