JP2021117483A - Polarizing plate, polarizing plate with retardation layer, and image display device having the same - Google Patents

Abstract

To provide a thin polarizing plate and thin polarizing plate with a retardation layer, which offer superior durability in high-temperature high-humidity environments.SOLUTION: A polarizing plate of the present invention comprises a polarizer, an iodine permeation suppressing layer, and an adhesive layer arranged in the described order. The adhesive layer has an iodine presence index of 0.050 or less. A polarizing plate with a retardation layer according to the present invention comprises such a polarizing plate and a retardation layer disposed between the polarizer and the adhesive layer, the retardation layer being an alignment fixed layer of a liquid crystal compound having a circularly polarizing function and elliptically polarizing function.SELECTED DRAWING: Figure 1

Description

The present invention relates to a polarizing plate, a polarizing plate with a retardation layer, and an image display device using these.

In recent years, image display devices represented by liquid crystal display devices and electroluminescence (EL) display devices (for example, organic EL display devices and inorganic EL display devices) have rapidly become widespread. A polarizing plate and a retardation plate are typically used in the image display device. Practically, a polarizing plate with a retardation layer in which a polarizing plate and a retardation plate are integrated is widely used (for example, Patent Document 1), and recently, there is a strong demand for thinner image display devices. As a result, there is an increasing demand for thinner polarizing plates and polarizing plates with retardation layers. However, the thin polarizing plate and the polarizing plate with a retardation layer have a problem that the optical characteristics (typically, the degree of polarization) change greatly in a high temperature and high humidity environment, and the durability is insufficient.

Japanese Patent No. 3325560

The present invention has been made to solve the above-mentioned conventional problems, and a main object thereof is to provide a thin polarizing plate and a polarizing plate with a retardation layer having excellent durability in a high temperature and high humidity environment. It is in.

（式中、Ｘはビニル基、（メタ）アクリル基、スチリル基、（メタ）アクリルアミド基、ビニルエーテル基、エポキシ基、オキセタン基、ヒドロキシル基、アミノ基、アルデヒド基、および、カルボキシル基からなる群より選択される少なくとも１種の反応性基を含む官能基を表し、Ｒ^１およびＲ^２はそれぞれ独立して、水素原子、置換基を有していてもよい脂肪族炭化水素基、置換基を有していてもよいアリール基、または、置換基を有していてもよいヘテロ環基を表し、Ｒ^１およびＲ^２は互いに連結して環を形成してもよい）。
本発明の別の局面によれば、位相差層付偏光板が提供される。この位相差層付偏光板は、上記の偏光板と、上記偏光子と上記粘着剤層との間に配置された位相差層と、を有する。該位相差層は円偏光機能または楕円偏光機能を有する液晶化合物の配向固化層である。
１つの実施形態においては、上記位相差層は単一層であり、該位相差層のＲｅ（５５０）は１００ｎｍ〜１９０ｎｍであり、該位相差層の遅相軸と上記偏光子の吸収軸とのなす角度は４０°〜５０°である。
１つの実施形態においては、上記位相差層は、第１の液晶化合物の配向固化層と第２の液晶化合物の配向固化層との積層構造を有し；該第１の液晶化合物の配向固化層のＲｅ（５５０）は２００ｎｍ〜３００ｎｍであり、その遅相軸と上記偏光子の吸収軸とのなす角度は１０°〜２０°であり；該第２の液晶化合物の配向固化層のＲｅ（５５０）は１００ｎｍ〜１９０ｎｍであり、その遅相軸と該偏光子の吸収軸とのなす角度は７０°〜８０°である。
１つの実施形態においては、上記位相差層付偏光板は、総厚みが６０μｍ以下である。
本発明のさらに別の局面によれば、画像表示装置が提供される。この画像表示装置は、上記の偏光板または位相差層付偏光板を備える。
１つの実施形態においては、上記画像表示装置は、有機エレクトロルミネセンス表示装置または無機エレクトロルミネセンス表示装置である。 The polarizing plate of the present invention has a polarizer, an iodine permeation suppressing layer, and an adhesive layer in this order. The iodine presence index of the pressure-sensitive adhesive layer is 0.050 or less.
In one embodiment, the iodine permeation inhibitory layer is a solidified or thermosetting film of a coating film of an organic solvent solution of resin. In one embodiment, the glass transition temperature of the resin constituting the iodine permeation suppressing layer is 85 ° C. or higher, and the weight average molecular weight Mw is 25000 or higher.
In one embodiment, the iodine permeation suppressing layer is provided with two or more layers between the polarizer and the pressure-sensitive adhesive layer.
In one embodiment, the iodine permeation inhibitory layer has a thickness of 0.05 μm to 10 μm.
In one embodiment, the resin constituting the iodine permeation suppressing layer is represented by the formula (1) of more than 50 parts by weight (meth) acrylic monomer and more than 0 parts by weight and less than 50 parts by weight. Contains a copolymer obtained by polymerizing a monomer mixture containing a monomer:

(In the formula, X is a group consisting of a vinyl group, a (meth) acrylic 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. Represents a functional group containing at least one reactive group selected, and R ¹ and R ² each independently have a hydrogen atom, an aliphatic hydrocarbon group which may have a substituent, and a substituent. It represents an aryl group which may be used, or a heterocyclic group which may have a substituent, and R ¹ and R ² may be linked to each other to form a ring).
According to another aspect of the present invention, a polarizing plate with a retardation layer is provided. The polarizing plate with a retardation layer has the above-mentioned polarizing plate and the above-mentioned retardation layer arranged between the above-mentioned polarizing element and the above-mentioned pressure-sensitive adhesive layer. The retardation layer is an orientation-solidified layer of a liquid crystal compound having a circularly polarized light function or an elliptically polarized light function.
In one embodiment, the retardation layer is a single layer, the Re (550) of the retardation layer is 100 nm to 190 nm, and the slow axis of the retardation layer and the absorption axis of the polarizer The angle of formation is 40 ° to 50 °.
In one embodiment, the retardation layer has a laminated structure of an oriented solidified layer of a first liquid crystal compound and an oriented solidified layer of a second liquid crystal compound; an oriented solidified layer of the first liquid crystal compound. The Re (550) of the second 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 oriented solidification 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 °.
In one embodiment, the polarizing plate with a retardation layer has a total thickness of 60 μm or less.
According to yet another aspect of the present invention, an image display device is provided. This image display device includes the above-mentioned polarizing plate or a polarizing plate with a retardation layer.
In one embodiment, the image display device is an organic electroluminescence display device or an inorganic electroluminescence display device.

According to the embodiment of the present invention, a thin polarizing plate having excellent durability in a high temperature and high humidity environment and a phase difference are provided by providing a specific iodine permeation suppressing layer to control the iodine presence index of the pressure-sensitive adhesive layer. A layered polarizing plate can be realized. The iodine permeation suppressing layer that can be used in the embodiment of the present invention is a solidified or thermosetting product of a coating film of an organic solvent solution of a resin, and the glass transition temperature of the resin constituting the iodine permeation suppressing layer is 85 ° C. or higher. The weight average molecular weight Mw is 25,000 or more, and the iodine presence index of the pressure-sensitive adhesive layer in the embodiment of the present invention is 0.050 or less.

It is the schematic sectional drawing of the polarizing plate by one Embodiment of this invention. It is a schematic cross-sectional view of the polarizing plate with a retardation layer according to one Embodiment of this invention. It is a schematic cross-sectional view of the polarizing plate with a retardation layer according to another embodiment of this invention. It is a schematic cross-sectional view of the polarizing plate with a retardation layer according to still another embodiment of this invention. It is a schematic cross-sectional view of the polarizing plate with a retardation layer according to still another embodiment of this invention. It is a schematic cross-sectional view of the polarizing plate with a retardation layer according to still another embodiment of this invention. It is a schematic cross-sectional view of the polarizing plate with a retardation layer according to still another embodiment of this invention.

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

(Definition of terms and symbols)
Definitions of terms and symbols herein are as follows.
(1) Refractive index (nx, ny, nz)
"Nx" is the refractive index in the direction in which the in-plane refractive index is maximized (that is, the slow-phase axis direction), and "ny" is the in-plane direction orthogonal to the slow-phase axis (that is, the phase-advance axis direction). Is the refractive index of, and "nz" is the refractive index in the thickness direction.
(2) In-plane phase difference (Re)
“Re (λ)” is an in-plane phase difference measured with light having a wavelength of λ nm at 23 ° C. For example, "Re (550)" is an in-plane phase difference measured with light having a wavelength of 550 nm at 23 ° C. Re (λ) is obtained by the formula: Re (λ) = (nx−ny) × d, where d (nm) is the thickness of the layer (film).
(3) Phase difference in the thickness direction (Rth)
“Rth (λ)” is a phase difference in the thickness direction measured with light having a wavelength of λ nm at 23 ° C. For example, "Rth (550)" is a phase difference in the thickness direction measured with light having a wavelength of 550 nm at 23 ° C. Rth (λ) is obtained by the formula: Rth (λ) = (nx−nz) × d, where d (nm) is the thickness of the layer (film).
(4) Nz coefficient The Nz coefficient is obtained by Nz = Rth / Re.
(5) Angle When referring to an angle herein, the angle includes both clockwise and counterclockwise with respect to the reference direction. Therefore, for example, "45 °" means ± 45 °.

A. Polarizing plate A-1. Overall Configuration of Polarizing Plate FIG. 1 is a schematic cross-sectional view of a polarizing plate according to one embodiment of the present invention. The polarizing plate 10 typically has a protective layer 12, a polarizer 11, an iodine permeation suppressing layer 40, and an adhesive layer 30 in this order. Depending on the purpose, another protective layer (not shown) may be provided on the opposite side of the protector 11 from the protective layer 12. The pressure-sensitive adhesive layer 30 is provided as the outermost layer, and the polarizing plate can be attached to an image display device (substantially, an image display cell). The polarizing plate may be used as a viewing side polarizing plate or as a back side polarizing plate in an image display device.

In the embodiment of the present invention, as described above, the iodine permeation suppressing layer 40 is provided between the polarizer 11 and the pressure-sensitive adhesive layer 30. The iodine permeation suppressing layer is typically a solidified product or a thermosetting product of a coating film of an organic solvent solution of a resin. Further, the glass transition temperature (Tg) of the resin constituting the iodine permeation suppressing layer is, for example, 85 ° C. or higher, and the weight average molecular weight Mw is, for example, 25,000 or higher. By providing such an iodine permeation suppressing layer at a predetermined position on the polarizing plate, iodine in the polarizing element is released into the pressure-sensitive adhesive layer (finally, an image display device, substantially an image display cell) in a high-temperature and high-humidity environment. ) Can be significantly suppressed. As a result, it is possible to realize excellent durability in a high temperature and high humidity environment with a thin polarizing plate (details will be described later). Further, when the polarizing plate is applied to the image display device, corrosion of metal members (for example, electrodes, sensors, wirings, metal layers) of the image display device can be remarkably suppressed, and in a high temperature and high humidity environment. The increase in reflectance can be suppressed. Such an effect is peculiar to a thin polarizing plate. That is, the present inventors have described above as a means for preventing the transfer of iodine, which is one of the factors for the change in optical characteristics (typically, the degree of polarization) in a thin polarizing plate in a high temperature and high humidity environment. An iodine permeation suppressing layer (a solidified layer or a heat-curing layer of a coating film of a resin having a specific Tg and Mw in an organic solvent solution) is provided to set the iodine presence index (described later) of the pressure-sensitive adhesive layer to 0.050 or less. We have found that this is useful, and have completed the present invention. Further, as will be described later, the iodine permeation suppressing layer can be formed very thinly, and by providing the iodine permeation suppressing layer, the protective layer on the side opposite to the viewing side can be omitted. This effect can contribute to further thinning of the polarizing plate.

In the polarizing plate with a retardation layer, two or more iodine permeation suppressing layers may be provided between the polarizer and the pressure-sensitive adhesive layer (for example, FIGS. 5 and 6). When the polarizing plate with a retardation layer has two or more iodine permeation suppression layers, corrosion of the metal member can be remarkably suppressed when the polarizing plate with a retardation layer is applied to an image display device.

In the polarizing plate with a retardation layer shown in FIG. 4, two iodine permeation suppressing layers are provided between the polarizer and the pressure-sensitive adhesive layer. In the example shown in FIG. 5, the iodine permeation suppressing layer is provided with two layers, one between the polarizer 11 and the retardation layer 20, and the other between the retardation layer 20 and the pressure-sensitive adhesive layer 30. In one embodiment, the iodine permeation inhibitor layer is provided adjacent to the polarizer. In another embodiment, the iodine permeation inhibitory layer is provided adjacent to the retardation layer. In the present specification, "adjacent" means that they are directly laminated without an adhesive layer or the like.

In the polarizing plate with a retardation layer shown in FIG. 6, three iodine permeation suppressing layers are provided between the polarizing element and the pressure-sensitive adhesive layer. In the example shown in FIG. 6, the iodine permeation suppressing layer is provided with two layers between the polarizer 11 and the retardation layer 20, and one layer between the retardation layer 20 and the pressure-sensitive adhesive layer 30. ing. The two iodine permeation suppressing layers between the polarizer 11 and the retardation layer 20 are provided adjacent to the polarizer and the other adjacent to the retardation layer.

In the polarizing plate with a retardation layer, the iodine permeation suppressing layer may be 4 or more layers (for example, 4 layers, 5 layers, 6 layers). The larger the number of iodine permeation suppressing layers, the higher the metal corrosion suppressing effect. The number of iodine permeation suppressing layers can be set in consideration of cost, manufacturing efficiency, total thickness of the polarizing plate with a retardation layer, and the like.

In the embodiment of the present invention, as described above, the iodine presence index of the pressure-sensitive adhesive layer 30 is 0.050 or less. The iodine presence index is preferably 0.040 or less, more preferably 0.030 or less, still more preferably 0.020 or less, and particularly preferably 0.015 or less. The smaller the iodine abundance index is, the more preferable it is, ideally it is zero, and the lower limit thereof can be, for example, 0.001. The iodine abundance index is an index of the amount of iodine transferred from the polarizer to the pressure-sensitive adhesive layer in a high-temperature and high-humidity environment. Indicates that the change in is small. Therefore, when the iodine presence index is in such a range, the transfer of iodine is suppressed, and excellent durability in a high temperature and high humidity environment can be realized in a thin polarizing plate (details will be described later). The iodine abundance index is determined by secondary ion mass spectrometry (TOF) on the polarizing plate after a reliability test (placed in an environment of 85 ° C. and 85% RH for 240 hours and then left in an environment of 23 ° C. and 55% RH for 24 hours). -SIMS). More specifically, the iodine presence index was measured by TOF-SIMS on the surface of the pressure-sensitive adhesive layer after the reliability test, and among the negative secondary ions obtained, C ₃ H ₃ O _{2 derived from acrylic (tacky agent) was obtained.} ^{The ionic strength of −} (m / z = 71) and the ionic strength of I ⁻ (m / z = 127) derived from iodine can be extracted and calculated using the following formula.
Iodine presence index = I ^- ionic strength / C ₃ H ₃ O ₂ ^- ionic strength Since a structure well known in the industry can be adopted for the pressure-sensitive adhesive layer 30, the detailed structure of the pressure-sensitive adhesive layer will be omitted. ..

The polarizing plate according to the embodiment of the present invention may be single-wafered or elongated. As used herein, the term "long" means an elongated shape having a length sufficiently long with respect to the width, and for example, an elongated shape having a length of 10 times or more, preferably 20 times or more with respect to the width. include. The elongated polarizing plate can be wound in a roll shape.

The total thickness of the polarizing plate is preferably 45 μm or less, more preferably 40 μm or less, still more preferably 35 μm or less, and particularly preferably 30 μm or less. The lower limit of the total thickness can be, for example, 22 μm. According to the embodiment of the present invention, such an extremely thin polarizing plate can be realized, and further, excellent durability in a high temperature and high humidity environment can be realized in such an extremely thin polarizing plate. Also, such polarizing plates can have very good flexibility and bending durability. Therefore, such polarizing plates may be particularly preferably applied to curved image display devices and / or foldable or foldable image display devices. The total thickness of the polarizing plate means the total thickness of the polarizer, the protective layer, the iodine permeation suppressing layer, and the adhesive layer or the pressure-sensitive adhesive layer for laminating them (that is, the total thickness of the polarizing plate is The thickness of the pressure-sensitive adhesive layer 30 and the release film that can be temporarily attached to the surface thereof is not included).

Practically, it is preferable that a release film is temporarily attached to the surface of the pressure-sensitive adhesive layer 30 until the polarizing plate is used. By temporarily attaching the release film, the pressure-sensitive adhesive layer can be protected and a roll of the polarizing plate can be formed.

A-2. Polarizer The polarizer is typically composed of a polyvinyl alcohol (PVA) -based 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. If the thickness of the polarizer is in such a range, it can greatly contribute to the thinning of the polarizing plate. Further, the effect of the present invention is remarkable in a thin polarizing plate using such a polarizer.

The boric acid content of the polarizer is preferably 10% by weight or more, more preferably 13% by weight to 25% by weight. When the boric acid content of the polarizer is in such a range, the ease of curl adjustment at the time of bonding is well maintained due to the synergistic effect with the iodine content described later, and the curl at the time of heating is maintained. It is possible to improve the appearance durability at the time of heating while satisfactorily suppressing the above. The boric acid content can be calculated as, for example, the amount of boric acid contained in the polarizer per unit weight by using the following formula from the neutralization method.

The iodine content of the polarizer is preferably 2% by weight or more, more preferably 2% by weight to 10% by weight. When the iodine content of the polarizer is in such a range, the ease of curl adjustment at the time of bonding is well maintained due to the synergistic effect with the above boric acid content, and the curl at the time of heating is maintained. It is possible to improve the appearance durability at the time of heating while satisfactorily suppressing the above. As used herein, the term "iodine content" means the amount of all iodine contained in the polarizer (PVA-based resin film). More specifically, in the polarizer ^{, iodine exists in the form of iodine ion (I −} ), iodine molecule (I ₂ ), polyiodine ion (I ₃ ⁻ , I ₅ ⁻ ), etc., as used herein. Iodine content means the amount of iodine that includes all of these forms. The iodine content can be calculated, for example, by the calibration curve method of fluorescent X-ray analysis. The polyiodine ion exists in a state in which a PVA-iodine complex is formed in the polarizer. By forming such a complex, absorption dichroism can be exhibited in the wavelength range of visible light. Specifically, a complex of PVA and tri-iodide ion (PVA · _{I 3} ^-) has a light absorption peak around 470 nm, a complex of PVA and five iodide ion (PVA · _{I 5} ^-) is 600nm near Has an absorptive peak. As a result, polyiodine ions can absorb light in a wide range of visible light, depending on their morphology. On the other hand, iodide ion (I ⁻ ) has an absorption peak near 230 nm and is not substantially involved in the absorption of visible light. Therefore, polyiodine ions present in the form of a complex with PVA may be mainly involved in the absorption performance of the polarizer.

The polarizer preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The simple substance transmittance Ts of the polarizer is preferably 40% to 48%, more preferably 41% to 46%. The degree of polarization P of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and further preferably 99.9% or more. The single transmittance is typically a Y value measured using an ultraviolet-visible spectrophotometer and corrected for luminosity factor. The degree of polarization is typically obtained by the following formula based on the parallel transmittance Tp and the orthogonal transmittance Tc measured by using an ultraviolet-visible spectrophotometer and corrected for luminosity factor.
Polarization degree (%) = {(Tp-Tc) / (Tp + Tc)} ^1/2 × 100

The polarizer can typically be made using a laminate of two or more layers. Specific examples of the polarizer obtained by using the laminate include a polarizer obtained by using a laminate of a resin base material and a PVA-based resin layer coated and formed on the resin base material. The polarizer obtained by using the laminate of the resin base material and the PVA-based resin layer coated and formed on the resin base material is, for example, a resin base material obtained by applying a PVA-based resin solution to the resin base material and drying the resin base material. It is produced by forming a PVA-based resin layer on the PVA-based resin layer to obtain a laminate of a resin base material and a PVA-based resin layer; stretching and dyeing the laminate to make the PVA-based resin layer a polarizer. obtain. Stretching typically involves immersing the laminate in an aqueous boric acid solution for stretching. Further, stretching may further include, if necessary, stretching the laminate in the air at a high temperature (eg, 95 ° C. or higher) prior to stretching in boric acid aqueous solution. The obtained resin substrate / polarizer laminate may be used as it is (that is, the resin substrate may be used as a protective layer for the polarizer), and the resin substrate is peeled off from the resin substrate / polarizer laminate. Then, an arbitrary appropriate protective layer according to the purpose may be laminated on the peeled surface. Details of the method for producing such a polarizer are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580 and Japanese Patent No. 6470455. The entire description of these publications is incorporated herein by reference.

A typical method for producing a polarizer is to form a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin on one side of a long thermoplastic resin base material to form a laminate. Then, the laminated body is subjected to an aerial auxiliary stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment in which the laminate is shrunk by 2% or more in the width direction by heating while being conveyed in the longitudinal direction. including. This makes it possible to provide a polarizer that is extremely thin, has excellent optical characteristics, and suppresses variations in optical characteristics. That is, by introducing the auxiliary stretching, even when PVA is applied on the thermoplastic resin, the crystallinity of PVA can be enhanced, and high optical characteristics can be achieved. At the same time, by increasing the orientation of PVA in advance, it is possible to prevent problems such as deterioration of PVA orientation and dissolution when immersed in water in a subsequent dyeing step or stretching step, resulting in high optical characteristics. Will be possible to achieve. Further, when the PVA-based resin layer is immersed in a liquid, the disorder of the orientation of the polyvinyl alcohol molecules and the decrease in the orientation can be suppressed as compared with the case where the PVA-based resin layer does not contain a halide. This makes it possible to improve the optical characteristics of the polarizer obtained through a treatment step of immersing the laminate in a liquid, such as a dyeing treatment and a stretching treatment in water. Further, the optical characteristics can be improved by shrinking the laminated body in the width direction by the drying shrinkage treatment.

A-3. Protective layer The protective layer 12 is formed of any suitable film that can be used as a protective layer for the polarizer. Specific examples of the material that is the main component of the film include cellulose-based resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, and polysulfone-based. , Polyester-based, polycarbonate-based, polyolefin-based, (meth) acrylic-based, acetate-based transparent resins and the like. Further, thermosetting resins such as (meth) acrylic, urethane, (meth) acrylic urethane, epoxy, and silicone, or ultraviolet curable resins can also be mentioned. In addition to this, for example, glassy polymers such as siloxane-based polymers can also be mentioned. Further, the polymer film described in JP-A-2001-343529 (WO01 / 37007) can also be used. As the material of this film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain. Can be used, and examples thereof include a resin composition having an alternating copolymer composed of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer. The polymer film can be, for example, an extruded product of the above resin composition.

In one embodiment, the polarizing plate is arranged on the visible side of the image display device, and the protective layer 12 is typically arranged on the visible side thereof. In such a case, the protective layer 12 may be subjected to surface treatment such as hard coat treatment, antireflection treatment, anti-sticking treatment, and anti-glare treatment, if necessary. Further / or, if necessary, the protective layer 12 is provided with a process for improving visibility when visually recognizing through polarized sunglasses (typically, a (elliptical) circularly polarized light function is provided, and an ultra-high phase difference is provided. May be given). By performing such a process, excellent visibility can be realized even when the display screen is visually recognized through a polarized lens such as polarized sunglasses. Therefore, the polarizing plate can also be suitably applied to an image display device that can be used outdoors.

The thickness of the protective layer is preferably 10 μm to 50 μm, more preferably 10 μm to 30 μm. When the surface treatment is applied, the thickness of the outer protective layer is the thickness including the thickness of the surface treatment layer.

A-4. Iodine permeation suppression layer The iodine permeation suppression layer is, as described above, a solidified product or a thermosetting product of a coating film of an organic solvent solution of a resin. With such a configuration, the thickness can be made very thin (for example, 10 μm or less). The thickness of the iodine permeation inhibitory 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. Is. Further, with such a configuration, the iodine permeation inhibitory layer can be formed directly on the polarizer (that is, without an adhesive layer or an adhesive layer). According to the embodiment of the present invention, as described above, the polarizer and the iodine permeation suppressing layer are very thin, and the adhesive layer or the pressure-sensitive adhesive layer for laminating the iodine permeation suppressing layer can be omitted. The total thickness of the polarizing plate can be made extremely thin. Further, such an iodine permeation suppressing layer has an advantage that it is excellent in humidification durability because it has a smaller hygroscopicity and moisture permeability than a solidified water-based coating film such as an aqueous solution or an aqueous dispersion. As a result, it is possible to realize a polarizing plate having excellent durability that can maintain optical characteristics even in a high temperature and high humidity environment. Further, such an iodine permeation suppressing layer can suppress an adverse effect on a polarizing plate (polarizer) due to ultraviolet irradiation as compared with a cured product of, for example, an ultraviolet curable resin. The iodine permeation inhibitory layer is preferably a solidified coating film of a resin organic solvent solution. The solidified product has a smaller shrinkage during film molding than the cured product, and since it does not contain residual monomers, deterioration of the film itself is suppressed, and the solidified product has a resistance to a polarizing plate (polarizer) caused by the residual monomers and the like. The adverse effect can be suppressed.

Further, the glass transition temperature (Tg) of the resin constituting the iodine permeation suppressing layer is, for example, 85 ° C. or higher, and the weight average molecular weight Mw is, for example, 25,000 or higher. When the Tg and Mw of the resin are in such a range, the effect synergistically with the effect of forming the iodine permeation suppressing layer with a solidified product or a thermosetting material of the coating film of the organic solvent solution of the resin is extremely effective. Despite its thinness, the transfer of iodine in the polarizer to the pressure-sensitive adhesive layer (eventually, the image display cell) can be remarkably suppressed. As a result, excellent durability in a high temperature and high humidity environment can be realized. The Tg of the resin is preferably 90 ° C. or higher, more preferably 100 ° C. or higher, still more preferably 110 ° C. or higher, and particularly preferably 120 ° C. or higher. The upper limit of Tg can be, for example, 200 ° C. 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.

As the resin constituting the iodine permeation suppressing layer, any suitable thermoplastic resin can be formed as long as it can form a solidified product or a thermosetting product of a coating film of an organic solvent solution and has Tg and Mw as described above. Alternatively, a thermosetting resin can be used. A thermoplastic resin is preferable. Examples of the thermoplastic resin include acrylic resins and epoxy resins. Acrylic resin and epoxy resin may be used in combination. Hereinafter, typical examples of the acrylic resin and the epoxy resin that can be used for the iodine permeation suppressing layer will be described.

The acrylic resin typically contains a repeating unit derived from a (meth) acrylic acid ester-based monomer having a linear or branched structure as a main component. As used herein, the term (meth) acrylic refers to acrylic and / or methacryl. The acrylic resin may contain repeating units derived from any suitable copolymerized monomer depending on the intended purpose. Examples of the copolymerization monomer (copolymerization monomer) include a carboxyl group-containing monomer, a hydroxyl group-containing monomer, an amide group-containing monomer, an aromatic ring-containing (meth) acrylate, and a heterocyclic ring-containing vinyl-based monomer. By appropriately setting the type, number, combination, copolymerization ratio, etc. of the monomer units, an acrylic resin having the above-mentioned predetermined Mw can be obtained.

（式中、Ｘはビニル基、（メタ）アクリル基、スチリル基、（メタ）アクリルアミド基、ビニルエーテル基、エポキシ基、オキセタン基、ヒドロキシル基、アミノ基、アルデヒド基、および、カルボキシル基からなる群より選択される少なくとも１種の反応性基を含む官能基を表し、Ｒ^１およびＲ^２はそれぞれ独立して、水素原子、置換基を有していてもよい脂肪族炭化水素基、置換基を有していてもよいアリール基、または、置換基を有していてもよいヘテロ環基を表し、Ｒ^１およびＲ^２は互いに連結して環を形成してもよい）。 <Boron-containing acrylic resin>
In one embodiment, the acrylic resin is a (meth) acrylic monomer having a weight of more than 50 parts by weight and a monomer having a weight of more than 0 parts by weight and less than 50 parts by weight (hereinafter, represented by the formula (1)). , May be referred to as a copolymerized monomer) and a copolymer obtained by polymerizing a monomer mixture (hereinafter, may be referred to as a boron-containing acrylic resin).

(In the formula, X is a group consisting of a vinyl group, a (meth) acrylic 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. Represents a functional group containing at least one reactive group selected, and R ¹ and R ² each independently have a hydrogen atom, an aliphatic hydrocarbon group which may have a substituent, and a substituent. It represents an aryl group which may be used, or a heterocyclic group which may have a substituent, and R ¹ and R ² may be linked to each other to form a ring).

（式中、Ｒ^６は任意の官能基を表し、jおよびｋは１以上の整数を表す）。 The boron-containing acrylic resin typically has a repeating unit represented by the following formula. By polymerizing a monomer mixture containing the copolymerization monomer represented by the formula (1) and the (meth) acrylic monomer, the boron-containing acrylic resin has a substituent containing boron in the side chain (for example,). It has a repeating unit of k in the following formula). As a result, when the iodine permeation suppressing layer is arranged adjacent to the polarizer, the adhesion to the polarizer can be improved. The boron-containing substituent may be continuously (that is, in a block shape) contained in the boron-containing acrylic resin, or may be randomly contained.

(In the formula, R ⁶ represents an arbitrary functional group, and j and k represent integers of 1 or more).

<(Meta) acrylic monomer>
Any suitable (meth) acrylic monomer can be used as the (meth) acrylic monomer. For example, a (meth) acrylic acid ester-based monomer having a linear or branched structure and a (meth) acrylic acid ester-based monomer having a cyclic structure can be mentioned.

Examples of the (meth) acrylic acid ester-based monomer having a linear or branched structure include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and (meth) acrylic acid. Examples thereof include isopropyl, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, methyl 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate and the like. .. Preferably, methyl (meth) acrylate is used. As the (meth) acrylic acid ester-based monomer, only one type may be used, or two or more types may be used in combination.

Examples of the (meth) acrylate-based monomer having a cyclic structure include cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, 1-adamantyl (meth) acrylate, and ( Dicyclopentenyl acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, biphenyl (meth) acrylate, o-biphenyloxyethyl (meth) acrylate, o-biphenyloxyethoxy Ethyl (meth) acrylate, m-biphenyloxyethyl acrylate, 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) Examples thereof include biphenyl group-containing monomers such as acryloyloxyethyl-m-biphenyl = carbamate and o-phenylphenol glycidyl ether acrylate, terphenyl (meth) acrylate, and o-terphenyloxyethyl (meth) acrylate. Preferably, 1-adamantyl (meth) acrylate and dicyclopentanyl (meth) acrylate are used. By using these monomers, a polymer having a high glass transition temperature can be obtained. Only one kind of these monomers may be used, or two or more kinds thereof may be used in combination.

Further, instead of the (meth) acrylic acid ester-based monomer, a silsesquioxane compound having a (meth) acryloyl group may be used. By using the silsesquioxane compound, an acrylic polymer having a high glass transition temperature can be obtained. The silsesquioxane compound is known to have various skeletal structures, for example, a basket-shaped structure, a ladder-shaped structure, and a random structure. The silsesquioxane compound may have only one of these structures, or may have two or more of these structures. Only one kind of silsesquioxane compound may be used, or two or more kinds may be used in combination.

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

The (meth) acrylic monomer is used in an amount of more than 50 parts by weight with respect to 100 parts by weight of the monomer mixture.

<Copolymerization monomer>
As the copolymerization monomer, a monomer represented by the above formula (1) is used. By using such a copolymerization monomer, a substituent containing boron is introduced into the side chain of the obtained polymer. Only one type of copolymerization monomer may be used, or two or more types may be used in combination.

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

The reactive group contained in the functional group represented by X is a vinyl group, a (meth) acrylic 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 the like. And at least one selected from the group consisting of carboxyl groups. Preferably, the reactive group is a (meth) acrylic group and / or a (meth) acrylamide group. By having these reactive groups, the adhesion to the polarizer can be further improved when the iodine permeation inhibitory layer is arranged adjacent to the polarizer.

In one embodiment, the functional group represented by X is preferably a functional group represented by ZZ. Here, Z is selected from the group consisting of a vinyl group, a (meth) acrylic 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. Represents a functional group containing at least one reactive group, where Y represents a phenylene group or an alkylene group.

Specifically, the following compounds can be used as the copolymerization monomer.

The copolymerized monomer is used in an amount of more than 0 parts by weight and less than 50 parts by weight with respect to 100 parts by weight of the monomer mixture. It is preferably 0.01 parts by weight or more and less than 50 parts by weight, more preferably 0.05 parts by weight to 20 parts by weight, still more preferably 0.1 parts by weight to 10 parts by weight, and particularly preferably 0. It is 5 parts by weight to 5 parts by weight.

<Acrylic resin containing lactone ring, etc.>

In another embodiment, the acrylic resin has a repeating unit containing a ring structure selected from a lactone ring unit, a glutaric anhydride unit, a glutarimide unit, a maleic anhydride unit and a maleimide (N-substituted maleimide) unit. .. Only one type of the repeating unit including the ring structure may be contained in the repeating unit of the acrylic resin, or two or more types may be contained.

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

一般式（２）において、Ｒ^２、Ｒ^３およびＲ^４は、それぞれ独立して、水素原子または炭素数１〜２０の有機残基を表す。なお、有機残基は酸素原子を含んでいてもよい。アクリル系樹脂には、単一のラクトン環単位のみが含まれていてもよく、上記一般式（２）におけるＲ^２、Ｒ^３およびＲ^４が異なる複数のラクトン環単位が含まれていてもよい。ラクトン環単位を有するアクリル系樹脂は、例えば特開２００８−１８１０７８号公報に記載されており、当該公報の記載は本明細書に参考として援用される。

In the general formula (2), R ² , R ³ and R ⁴ independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms. The organic residue may contain an oxygen atom. The acrylic resin may be contained only a single lactone ring units may be R ^2, R ³ and R ⁴ in the general formula (2) is contains different lactone ring unit .. An acrylic resin having a lactone ring unit is described in, for example, Japanese Patent Application Laid-Open No. 2008-181078, and the description in this publication is incorporated herein by reference.

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

In the general formula (3), R ¹¹ and R ¹² independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ¹³ is an alkyl group having 1 to 18 carbon atoms and 3 to 12 carbon atoms. The cycloalkyl group of the above, or an aryl group having 6 to 10 carbon atoms is shown. In the general formula (3), preferably R ¹¹ and R ¹² are independently hydrogen or methyl groups, and R ¹³ is a hydrogen, methyl group, butyl group or cyclohexyl group, respectively. More preferably, R ¹¹ is a methyl group, R ¹² is hydrogen, and R ¹³ is a methyl group. The acrylic resin may contain only a single glutarimide unit, or may contain a plurality of glutarimide units having different ^{R 11} , R ¹² and R ^{13 in the above general formula (3).} .. Examples of the acrylic resin having a glutarimide unit include JP-A-2006-309033, JP-A-2006-317560, JP-A-2006-328334, JP-A-2006-337491, and JP-A-2006-337492. It is described in Japanese Patent Application Laid-Open No. 2006-337493 and Japanese Patent Application Laid-Open No. 2006-337569, and the description of the relevant publication is incorporated herein by reference. Note that the glutaric anhydride units, nitrogen atom substituted by R ¹³ in the general formula (3), except that the oxygen atom, the above description is applied about the glutarimide units.

Since the structure of the maleic anhydride unit and the maleimide (N-substituted maleimide) unit is specified from the name, specific description thereof will be omitted.

The content ratio of the repeating unit including the ring structure in the acrylic resin is preferably 1 mol% to 50 mol%, more preferably 10 mol% to 40 mol%, and further preferably 20 mol% to 30 mol%. The acrylic resin contains the above-mentioned (meth) acrylic monomer-derived repeating unit as the main repeating unit.

<Epoxy resin>
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, the adhesion between the iodine permeation suppressing layer and the polarizer can be improved. Further, when the pressure-sensitive adhesive layer is arranged adjacent to the iodine permeation suppressing layer, the anchoring force of the pressure-sensitive adhesive layer can be improved. Examples of the epoxy resin having an aromatic ring include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin and other bisphenol type epoxy resins; phenol novolac epoxy resin, cresol novolac epoxy resin, hydroxybenzaldehyde phenol novolac. Novolak type epoxy resin such as epoxy resin; polyfunctional epoxy resin such as tetrahydroxyphenylmethane glycidyl ether, tetrahydroxybenzophenone glycidyl ether, epoxidized polyvinylphenol, naphthol type epoxy resin, naphthalene type epoxy resin, biphenyl type Epoxy resin and the like can be mentioned. Preferably, a bisphenol A type epoxy resin, a biphenyl type epoxy resin, or a bisphenol F type epoxy resin is used. Only one type of epoxy resin may be used, or two or more types may be used in combination.

The iodine permeation suppressing layer can be formed by applying an organic solvent solution of a resin as described above to form a coating film, and solidifying or thermosetting the coating film. As the organic solvent, any suitable organic solvent capable of dissolving or uniformly dispersing the acrylic resin can be used. Specific examples of the organic solvent include ethyl acetate, toluene, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), cyclopentanone, and cyclohexanone. The resin concentration of the solution is preferably 3 parts by weight to 20 parts by weight with respect to 100 parts by weight of the solvent. With such a resin concentration, a uniform coating film can be formed.

The solution may be applied to any suitable substrate or to a polarizer. When the solution is applied to the substrate, the solidified product (iodine permeation inhibitory layer) of the coating film formed on the substrate is transferred to the polarizer. When the solution is applied to the polarizer, the protective layer is directly formed on the polarizer by drying (solidifying) the coating film. Preferably, the solution is applied to the polarizer and a protective layer is formed directly on the polarizer. With such a configuration, the adhesive layer or the pressure-sensitive adhesive layer required for transfer can be omitted, so that the polarizing plate can be further thinned. Any suitable method can be adopted as the method for applying the solution. Specific examples include a roll coating method, a spin coating method, a wire bar coating method, a dip coating method, a die coating method, a curtain coating method, a spray coating method, and a knife coating method (comma coating method, etc.).

An iodine permeation inhibitory layer can be formed by solidifying or thermosetting the coating film of the solution. The heating temperature for solidification or thermosetting is preferably 100 ° C. or lower, more preferably 50 ° C. to 70 ° C. When the heating temperature is in such a range, it is possible to prevent an adverse effect on the polarizer. The heating time can vary depending on the heating temperature. The heating time can be, for example, 1 minute to 10 minutes.

The iodine permeation suppressing layer (substantially, an organic solvent solution of the above resin) may contain any suitable additive depending on the purpose. Specific examples of additives include ultraviolet absorbers; leveling agents; antioxidants such as hindered phenols, phosphorus and sulfur; stabilizers such as light-resistant stabilizers, weather-resistant stabilizers and heat-stabilizing agents; glass fibers, Reinforcing materials such as carbon fibers; Near infrared absorbers; Flame retardants such as tris (dibromopropyl) phosphate, triallyl phosphate, antimony oxide; Antistatic agents such as anionic, cationic and nonionic surfactants; Inorganic pigments , Organic pigments, colorants such as dyes; organic fillers or inorganic fillers; resin modifiers; organic fillers and inorganic fillers; plasticizers; lubricants; antistatic agents; flame retardants; and the like. The type, number, combination, amount of additive, etc. of the additive can be appropriately set according to the purpose.

The iodine permeation inhibitory layer has, for example, an iodine absorption index of 0.015 or less. The iodine absorption index is preferably 0.012 or less, more preferably 0.009 or less, still more preferably 0.007 or less, and particularly preferably 0.005 or less. The smaller the iodine absorption index is, the more preferable it is, ideally it is zero, and the lower limit thereof can be, for example, 0.001. The iodine absorption index is an index of the iodine permeation suppressing ability of the iodine permeation suppressing layer, and the smaller this index is, the less iodine is absorbed by the iodine permeation suppressing layer (that is, iodine is easily blocked by the iodine permeation suppressing layer). show. Therefore, if the iodine absorption index is in such a range, the iodine presence index of the pressure-sensitive adhesive layer can be set to 0.050 or less as described above, and the iodine in the polarizer is the pressure-sensitive adhesive layer (finally). It is possible to remarkably suppress the transition to the image display device, substantially the image display cell). As a result, it is possible to realize excellent durability in a high temperature and high humidity environment in a thin polarizing plate. Further, when the polarizing plate is applied to an image display device, corrosion of metal members (for example, electrodes, sensors, wirings, metal layers) of the image display device can be remarkably suppressed, and in a high temperature and high humidity environment. In, the decrease in reliability caused by iodine can be suppressed, and therefore the increase in reflectance can be suppressed. Further, as described above, the iodine permeation inhibitory layer has a potassium absorption index of preferably 0.015 or less. The potassium absorption index is more preferably 0.013 or less, further preferably 0.011 or less, and particularly preferably 0.009 or less. The smaller the potassium absorption index, the better, ideally zero, the lower limit of which can be, for example, 0.002. The potassium absorption index is an index of the potassium permeation inhibitory ability of the iodine permeation inhibitory layer, and the smaller this index is, the more difficult it is for potassium to be absorbed by the iodine permeation inhibitory layer. It shows that iodine in the form of I ₃ ^- K ⁺ ) is difficult to be absorbed by the iodine permeation inhibitory layer. Therefore, if the potassium absorption index is within such a range, the transfer of iodine can be suppressed not only in the form of elemental iodine but also in the form of potassium iodide and potassium polyiodine. The iodine absorption index can be defined as the iodine intensity (kcps) obtained by fluorescent X-ray analysis of the iodine permeation inhibitory layer, and the potassium absorption index can be defined as the potassium intensity (kcps) obtained by fluorescent X-ray analysis of the iodine permeation inhibitory layer. Can be specified.

B. Polarizing plate with retardation layer B-1. Overall configuration of polarizing plate with retardation layer The polarizing plate with retardation layer according to the embodiment of the present invention has a polarizing plate and a retardation layer. The polarizing plate is the polarizing plate according to the above item A. In the embodiment of the present invention, the retardation layer is arranged between the polarizer and the pressure-sensitive adhesive layer. The retardation layer is an oriented solidified layer of a liquid crystal compound having a circularly polarized light function or an elliptically polarized light function (hereinafter, may be simply referred to as a liquid crystal oriented solidified layer). FIG. 2A is a schematic cross-sectional view of a polarizing plate with a retardation layer according to one embodiment of the present invention; FIG. 2B is a schematic cross-sectional view of a polarizing plate with a retardation layer according to another embodiment of the present invention. The polarizing plates with retardation layers 100 and 101 of FIGS. 2A and 2B each have a protective layer 12, a polarizer 11, a retardation layer 20, and an adhesive layer 30 in this order from the visual side. In the embodiment of the present invention, the iodine permeation suppressing layer 40 is provided between the polarizer 11 and the pressure-sensitive adhesive layer 30. By providing the iodine permeation suppressing layer in the polarizing plate with a retardation layer, iodine in the polarizer is transferred to the pressure-sensitive adhesive layer (finally the image display device, substantially the image display cell) as described above for the polarizing plate. The transition can be significantly suppressed. As a result, it is possible to realize excellent durability in a high temperature and high humidity environment in a thin polarizing plate with a retardation layer. Further, when a polarizing plate with a retardation layer is applied to an image display device, corrosion of metal members (for example, electrodes, sensors, wirings, metal layers) of the image display device can be remarkably suppressed, and the temperature is high. It is possible to suppress an increase in reflectance in a high humidity environment. The iodine permeation suppressing layer 40 may be provided between the polarizer 11 and the retardation layer 20 (that is, adjacent to the polarizer 11) as shown in FIG. 2A, and the retardation difference as shown in FIG. 2B. It may be provided between the layer 20 and the pressure-sensitive adhesive layer 30. When the iodine permeation suppressing layer is provided between the polarizer and the retardation layer (particularly when the iodine permeation suppressing layer is adjacent to the polarizer), it is possible to suppress iodine transfer from the polarizer in a high temperature and high humidity environment. It has the advantage of improving reliability. When the iodine permeation suppressing layer is provided between the retardation layer and the pressure-sensitive adhesive layer (particularly when the iodine permeation suppressing layer is adjacent to the pressure-sensitive adhesive layer), components that are considered to affect metal corrosion other than iodine (for example). , Residual monomer component in the ultraviolet curable adhesive, decomposition product of the photoinitiator) can also be prevented from migrating into the adhesive at the same time, and has the advantage of further enhancing the metal corrosion suppressing effect.

As shown in FIG. 3, in the polarizing plate 102 with a retardation layer according to still another embodiment, another retardation layer 50 and / or a conductive layer or an isotropic base material 60 with a conductive layer may be provided. Another retardation layer 50 is typically provided between the retardation 20 and the pressure-sensitive adhesive layer 30 (ie, outside the retardation layer 20). Another retardation layer typically exhibits a relationship in which the refractive index characteristic is nz> nz = ny. The conductive layer or the isotropic base material 60 with the conductive layer is typically provided between the iodine permeation suppressing layer 40 and the pressure-sensitive adhesive layer 30 (that is, outside the iodine permeation suppressing layer 40). Another retardation layer 50 and the conductive layer or the isotropic base material 60 with the conductive layer are typically provided in this order from the retardation layer 20 side. In the illustrated example, the iodine permeation suppressing layer 40, the retardation layer 20, another retardation layer 50, and the conductive layer or the isotropic base material 60 with the conductive layer are provided in this order from the visual side, but different retardation. Any is provided as long as the layer 50 is provided between the phase difference 20 and the pressure-sensitive adhesive layer 30, and the conductive layer or the isotropic base material 60 with the conductive layer is provided between the iodine permeation suppressing layer 40 and the pressure-sensitive adhesive layer 30. Appropriate placement order can be adopted. The other retardation layer 50 and the conductive layer or the isotropic base material 60 with the conductive layer are typically arbitrary layers provided as needed, and one or both of them may be omitted. For convenience, the retardation layer 20 may be referred to as a first retardation layer, and another retardation layer 50 may be referred to as a second retardation layer. When an isotropic base material with a conductive layer or a conductive layer is provided, the polarizing plate with a retardation layer is a so-called inner touch panel type in which a touch sensor is incorporated between an image display cell (for example, an organic EL cell) and the polarizing plate. Can be applied to input display devices. In the embodiment of the present invention, by providing the conductive layer or the isotropic base material 60 with the conductive layer on the outside of the iodine permeation suppressing layer 40, the corrosion of the conductive layer can be remarkably suppressed.

As described above, the first retardation layer 20 is a liquid crystal oriented solidifying layer. The first retardation layer 20 may be a single layer as shown in FIGS. 2A, 2B and 3, and the first liquid crystal oriented solidified layer 21 and the second liquid crystal oriented solidified layer as shown in FIG. It may have a laminated structure with 22.

The above embodiments may be combined as appropriate, and the components of the above embodiments may be modified in the art. For example, the polarizing plate 101 with a retardation layer of FIG. 2B may be provided with a second retardation layer 50 and / or an isotropic base material 60 with a conductive layer or a conductive layer; the polarizing plate 101 with a retardation layer of FIG. 2B. The retardation layer 20 of the above may have a two-layer structure as shown in FIG. 4; the polarizing plate 103 with the retardation layer of FIG. A square substrate 60 may be provided; the iodine permeation suppressing layer 40 of the polarizing plate 102 with a retardation layer of FIG. 3 may be provided between the retardation layer 20 and the conductive layer or the isotropic substrate 60 with a conductive layer. good.

The polarizing plate with a retardation layer according to the embodiment of the present invention may further include other retardation layers. The optical characteristics (for example, refractive index characteristics, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, arrangement position, and the like of other retardation layers can be appropriately set according to the purpose.

The total thickness of the polarizing plate with a retardation layer is preferably 60 μm or less, more preferably 55 μm or less, still more preferably 50 μm or less, and particularly preferably 40 μm or less. The lower limit of the total thickness can be, for example, 28 μm. According to the embodiment of the present invention, such an extremely thin polarizing plate with a retardation layer can be realized, and further, such a polarizing plate with an extremely thin retardation layer has excellent durability in a high temperature and high humidity environment. Sex can be realized. Further, even when such a polarizing plate with a very thin retardation layer is applied to an image display device, corrosion of metal members (for example, electrodes, sensors, wirings, metal layers) of the image display device is remarkable. It can be suppressed, and the increase in reflectance in a high temperature and high humidity environment can be suppressed. The total thickness of the polarizing plate with a retardation layer is the polarizing plate, the retardation layer (the first retardation layer and the second retardation layer if present), the iodine permeation suppression layer, and the layers thereof. The total thickness of the adhesive layer or the pressure-sensitive adhesive layer for the purpose (that is, the total thickness of the polarizing plate with the retardation layer is the conductive layer or the isotropic base material 60 with the conductive layer, and the pressure-sensitive adhesive layer 30 and its surface. Does not include the thickness of the release film that can be temporarily attached).

Among the above-mentioned items A regarding the configuration, effect and use of the polarizing plate, those that can be applied to the polarizing plate with the retardation layer can be incorporated as the description regarding the polarizing plate with the retardation layer. For example, the description regarding the shape (single-wafered or elongated) and thinning of the polarizing plate, the image display device to which the polarizing plate can be applied, the release film, and the direct formation of the iodine permeation suppressing layer on the polarizer is described as a phase difference. It can be incorporated as a description relating to a layered polarizing plate. Needless to say, these are examples, and the descriptions that can be incorporated are not limited to these. Similarly, any of the descriptions below regarding the configuration, effect and use of a polarizing plate with a retardation layer that can be incorporated into a polarizing plate can be incorporated as a description relating to a polarizing plate.

Hereinafter, the first retardation layer, the second retardation layer, and the conductive layer or the isotropic base material with the conductive layer, which are the constituent elements of the polarizing plate with the retardation layer, will be described. The polarizer, the protective layer, and the iodine permeation suppressing layer are as described in Section A above.

B-2. First Phase Difference Layer The first retardation layer 20 is a liquid crystal oriented solidifying layer as described above. By using the liquid crystal compound, the difference between nx and ny of the obtained retardation layer can be made much larger than that of the non-liquid crystal material, so that the thickness of the retardation layer for obtaining a desired in-plane retardation can be obtained. Can be made much smaller. As a result, it is possible to further reduce the thickness of the polarizing plate with a retardation layer. As used herein, the term "liquid crystal oriented solidified layer" refers to a layer in which a liquid crystal compound is oriented in a predetermined direction within the layer and the oriented state is fixed. The "oriented solidified layer" is a concept including an oriented cured layer obtained by curing a liquid crystal monomer as described later. In the present embodiment, the rod-shaped liquid crystal compounds are typically oriented in a state of being aligned in the slow-phase axial direction of the first retardation layer (homogeneous orientation).

Examples of the liquid crystal compound include a liquid crystal compound (nematic liquid crystal) in which the liquid crystal phase is a nematic phase. As such a liquid crystal compound, for example, a liquid crystal polymer or a liquid crystal monomer can be used. The liquid crystal expression mechanism of the liquid crystal compound may be either lyotropic or thermotropic. The liquid crystal polymer and the liquid crystal monomer may be used alone or in combination.

When the liquid crystal compound is a liquid crystal monomer, the liquid crystal monomer is preferably a polymerizable monomer and a crosslinkable monomer. This is because the orientation state of the liquid crystal monomer can be fixed by polymerizing or cross-linking (that is, curing) the liquid crystal monomer. After the liquid crystal monomers are oriented, for example, if the liquid crystal monomers are polymerized or crosslinked with each other, the oriented 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 formed first retardation layer does not undergo a transition to a liquid crystal phase, a glass phase, or a crystal phase due to a temperature change peculiar to a liquid crystal compound, for example. As a result, the first retardation layer becomes an extremely stable retardation layer that is not affected by temperature changes.

The temperature range in which the liquid crystal monomer exhibits liquid crystallinity differs depending on the type. 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.

As the liquid crystal monomer, any suitable liquid crystal monomer can be adopted. For example, the polymerizable mesogen compounds described in Special Tables 2002-533742 (WO00 / 37585), EP358208 (US5211877), EP66137 (US4388453), WO93 / 22397, EP02671712, DE19504224, DE4408171, GB2280445 and the like can be used. Specific examples of such a polymerizable mesogen compound include, for example, BASF's trade name LC242, Merck's trade name E7, and Wacker-Chem's trade name LC-Silicon-CC3767. As the liquid crystal monomer, for example, a nematic liquid crystal monomer is preferable.

The liquid crystal alignment solidified layer is subjected to an orientation treatment on the surface of a predetermined base material, and a coating liquid containing a liquid crystal compound is applied to the surface to orient the liquid crystal compound in a direction corresponding to the orientation treatment. It can be formed by fixing the state. In one embodiment, the substrate is any suitable resin film and the liquid crystal oriented solidified layer formed on the substrate is transferred to the surface of an adjacent layer (eg, a polarizer, an iodine permeation inhibitory layer). Can be done.

As the orientation treatment, any appropriate orientation treatment can be adopted. Specific examples thereof include mechanical orientation treatment, physical orientation treatment, and chemical orientation treatment. Specific examples of the mechanical orientation treatment include a rubbing treatment and a stretching treatment. Specific examples of the physical orientation treatment include magnetic field orientation treatment and electric field orientation treatment. Specific examples of the chemical alignment treatment include an orthorhombic deposition method and a photoalignment treatment. As the treatment conditions for various orientation treatments, any appropriate conditions can be adopted depending on the purpose.

The orientation of the liquid crystal compound is performed by treating at a temperature indicating the liquid crystal phase according to the type of the liquid crystal compound. By performing such temperature treatment, the liquid crystal compound takes a liquid crystal state, and the liquid crystal compound is oriented according to the orientation treatment direction of the surface of the base material.

In one embodiment, the orientation state is fixed by cooling the liquid crystal compound oriented as described above. When the liquid crystal compound is a polymerizable monomer or a crosslinkable monomer, the orientation state is fixed by subjecting the liquid crystal compound oriented as described above to a polymerization treatment or a crosslinking treatment.

Specific examples of the liquid crystal compound and details of the method for forming the oriented solidified layer are described in JP-A-2006-163343. The description of this gazette is incorporated herein by reference.

In one embodiment, the first retardation layer 20 is a single layer as shown in FIGS. 2A, 2B and 3. When the first retardation layer 20 is composed of a single layer, its thickness is preferably 0.5 μm to 7 μm, and more preferably 1 μm to 5 μm. By using the liquid crystal compound, it is possible to realize an in-plane phase difference equivalent to that of the resin film with a thickness much thinner than that of the resin film.

The first retardation layer has a circularly polarized light function or an elliptically polarized light function as described above. The first retardation layer typically shows a relationship in which the refractive index characteristic is nx> ny = nz. The first retardation layer is typically provided to impart antireflection characteristics to the polarizing plate, and can function as a λ / 4 plate when the first retardation layer is a single layer. In this case, 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 even more preferably 130 nm to 160 nm. Here, "ny = nz" includes not only the case where ny and nz are completely equal, but also the case where they are substantially equal. Therefore, ny> nz or ny <nz may occur within a range that does not impair the effects of the present invention.

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

The first retardation layer may exhibit a reverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light, and a positive wavelength dispersion characteristic in which the retardation value decreases according to the wavelength of the measurement light. It may be shown, or may 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 retardation layer exhibits inverse dispersion wavelength characteristics. In this case, the Re (450) / Re (550) of the retardation layer is preferably 0.8 or more and less than 1, and more preferably 0.8 or more and 0.95 or less. With such a configuration, very excellent antireflection characteristics can be realized.

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. It is 45 °. If the angle θ is in such a range, by using the λ / 4 plate as the first retardation layer as described above, very excellent circularly polarized light characteristics (as a result, very excellent antireflection characteristics). A polarizing plate with a retardation layer having the above can be obtained.

In another embodiment, the first retardation layer 20 may have a laminated structure of a first liquid crystal oriented solidified layer 21 and a second liquid crystal oriented solidified layer 22 as shown in FIG. In this case, either one of the first liquid crystal oriented solidified layer 21 and the second liquid crystal oriented solidified layer 22 may function as a λ / 4 plate, and the other may function as a λ / 2 plate. Therefore, the thicknesses of the first liquid crystal oriented solidified layer 21 and the second liquid crystal oriented solidified layer 22 can be adjusted so as to obtain a desired in-plane phase difference between the λ / 4 plate or the λ / 2 plate. For example, when the first liquid crystal oriented solidified layer 21 functions as a λ / 2 plate and the second liquid crystal oriented solidified layer 22 functions as a λ / 4 plate, the thickness of the first liquid crystal oriented solidified layer 21 is, for example, 2. The thickness is 0.0 μm to 3.0 μm, and the thickness of the second liquid crystal oriented solidifying layer 22 is, for example, 1.0 μm to 2.0 μm. In this case, the in-plane retardation Re (550) of the first liquid crystal oriented solidified layer is preferably 200 nm to 300 nm, more preferably 230 nm to 290 nm, and further preferably 250 nm to 280 nm. The in-plane retardation Re (550) of the second liquid crystal oriented solidified layer is as described above with respect to the single layer. The angle formed by the slow axis of the first liquid crystal oriented solidification layer and the absorption axis of the polarizer is preferably 10 ° to 20 °, more preferably 12 ° to 18 °, and even more preferably about 15 °. Is. The angle formed by the slow axis of the second liquid crystal oriented solidification layer and the absorption axis of the polarizer is preferably 70 ° to 80 °, more preferably 72 ° to 78 °, and even more preferably about 75 °. Is. With such a configuration, it is possible to obtain characteristics close to the ideal reverse wavelength dispersion characteristic, and as a result, it is possible to realize extremely excellent antireflection characteristics. The liquid crystal compounds constituting the first liquid crystal oriented solidified layer and the second liquid crystal oriented solidified layer, the method for forming the first liquid crystal oriented solidified layer and the second liquid crystal oriented solidified layer, the optical characteristics, and the like are described above with respect to the single layer. As explained in.

B-3. Second Phase Difference Layer The second phase difference layer can be a so-called positive C plate in which the refractive index characteristic shows a relationship of nz> nz = ny as described above. By using the positive C plate as the second retardation layer, it is possible to satisfactorily prevent reflection in the oblique direction, and it is possible to widen the viewing angle of the antireflection function. In this case, the retardation Rth (550) in the thickness direction of the second retardation layer is preferably −50 nm to −300 nm, more preferably −70 nm to −250 nm, still more preferably −90 nm to −200 nm, and particularly preferably. It is -100 nm to -180 nm. Here, "nx = ny" includes not only the case where nx and ny are exactly equal, but also the case where nx and ny are substantially equal. That is, the in-plane retardation Re (550) of the second retardation layer can be less than 10 nm.

The second retardation layer with a refractive index characteristic of nz> nx = ny can be formed of any suitable material. The second retardation layer preferably consists of a film containing a liquid crystal material fixed in a homeotropic orientation. The liquid crystal material (liquid crystal compound) that can be homeotropically oriented may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of the liquid crystal compound and the method for forming the retardation layer include the liquid crystal compounds described in [0020] to [0028] of JP-A-2002-333642 and the method for forming the retardation layer. In this case, the thickness of the second retardation layer is preferably 0.5 μm to 10 μm, more preferably 0.5 μm to 8 μm, and even more preferably 0.5 μm to 5 μm.

B-4. Conductive layer or isotropic base material with conductive layer The conductive layer is an arbitrary suitable base material by any suitable film forming method (for example, vacuum deposition method, sputtering method, CVD method, ion plating method, spray method, etc.). It can be formed by forming a metal oxide film on top of it. Examples of the metal oxide include indium oxide, tin oxide, zinc oxide, indium-tin composite oxide, tin-antimon composite oxide, zinc-aluminum composite oxide, and indium-zinc composite oxide. Of these, indium-tin composite oxide (ITO) is preferable.

When the conductive layer contains 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.

The conductive layer is transferred from the base material to the first retardation layer (or the iodine permeation suppression layer or the second retardation layer if present), and the conductive layer alone constitutes a polarizing plate with a retardation layer. It may be a layer, and is laminated on the first retardation layer (or the iodine permeation suppression layer or the second retardation layer if present) as a laminate with the base material (base material with a conductive layer). You may. Preferably, the substrate is optically isotropic, and therefore the conductive layer can be used as an isotropic substrate with a conductive layer in a polarizing plate with a retardation layer.

As the optically isotropic base material (isotropic base material), any suitable isotropic base material can be adopted. Examples of the material constituting the isotropic base material include a material having a resin having no conjugate system such as a norbornene resin and an olefin resin as a main skeleton, and an acrylic resin having a cyclic structure such as a lactone ring and a glutarimide ring. Examples include the material contained in the main chain. When such a material is used, when an isotropic base material is formed, the expression of the phase difference due to the orientation of the molecular chains can be suppressed to be small. The thickness of the isotropic base material is preferably 50 μm or less, more preferably 35 μm or less. The lower limit of the thickness of the isotropic base material is, for example, 20 μm.

The conductive layer and / or the conductive layer of the isotropic base material with the conductive layer can be patterned, if necessary. By patterning, a conductive portion and an insulating portion can be formed. As a result, electrodes can be formed. The electrode can function as a touch sensor electrode that senses contact with the touch panel. As the patterning method, any suitable method can be adopted. Specific examples of the patterning method include a wet etching method and a screen printing method.

C. Image Display Device The polarizing plate according to the above item A and the polarizing plate with a retardation layer according to the above item B 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 or a polarizing plate with a retardation layer. Typical examples of the image display device include a liquid crystal display device and an electroluminescence (EL) display device (for example, an organic EL display device and an inorganic EL display device). The image display device according to the embodiment of the present invention typically includes the polarizing plate according to the above item A or the polarizing plate with a retardation layer according to the above item B on the visible side thereof. The polarizing plate with a retardation layer is laminated so that the retardation layer is on the image display cell side (for example, a liquid crystal cell, an organic EL cell, an inorganic EL cell) (so that the polarizer is on the visual recognition side). Although such an image display device is extremely thin, corrosion of metal members is remarkably suppressed. In one embodiment, the image display device has a curved shape (substantially a curved display screen) and / or is foldable or foldable. The polarizing plate according to the above item A may be arranged on the back side of the image display device depending on the purpose.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. The measurement method of each characteristic is as follows. Unless otherwise specified, "parts" and "%" in Examples and Comparative Examples are based on weight.

(1) Thickness The thickness of 10 μm or less was measured using an interference film thickness meter (manufactured by Otsuka Electronics Co., Ltd., product name “MCPD-3000”). The thickness exceeding 10 μm was measured using a digital micrometer (manufactured by Anritsu, product name “KC-351C”).

(2) Iodine presence index The polarizing plate with a retardation layer or the polarizing plate obtained in Examples and Comparative Examples was bonded to non-alkali glass to prepare a test sample. This test sample was subjected to a reliability test (placed in an environment of 85 ° C. and 85% RH for 240 hours and then left in an environment of 23 ° C. and 55% RH for 24 hours), and then subjected to a non-alkali glass using a trimming knife. The adhesive was peeled off from the glass. The surface of the pressure-sensitive adhesive of the peeled test sample was subjected to secondary ion mass spectrometry (TOF-SIMS) measurement using "TOFSIMS5" manufactured by IONTOF. The measurement conditions were as follows.
-Irradiated primary ion: Bi ₃ ²⁺
・ Primary ion acceleration voltage: 25kV
-Measurement area: 100 μm ²
Measurement polarity: from the negative ions obtained negative secondary ions derived from an acrylic ^{_{(PSA) C 3 H 3 O 2 -}} (m / z = 71) of the ionic strength and from iodine ^I - (m / z The ionic strength of = 127) was extracted, and the iodine presence index was calculated using the following formula.
Iodine presence index = I ^- ionic strength / C ₃ H ₃ O ₂ ^- ion strength

(3) A polyethylene terephthalate (PET) film having an iodine absorption index and a potassium absorption index of 38 μm is coated with the resin solution used in Examples and Comparative Examples so that the thickness after drying becomes 1 μm, and the resin layer / A test sample of PET film was obtained. The obtained test sample was immersed in a 10% aqueous solution of potassium iodide adjusted to 23 ° C. (90 parts by weight of pure water, 10 parts by weight of potassium iodide) for 24 hours. After immersion, the test sample was taken out from the aqueous solution, water droplets on the surface were wiped off, and then the intensity (kcps) of iodine and potassium was obtained by fluorescent X-ray measurement on the surface of the resin layer. The strength of the obtained iodine was used as the iodine absorption index, and the strength of potassium was used as the potassium absorption index. The conditions for fluorescent X-ray analysis were as follows.
-Analyzer: Fluorescent X-ray analyzer (XRF) manufactured by Rigaku Denki Kogyo Co., Ltd., product name "ZSX100e"
-Test sample: Circular sample with a diameter of 10 mm-Cathode: Rhodium-Spectroscopic crystal: Lithium fluoride-Excitation light energy: 40 kV-90 mA
-Iodine measurement line: I-LA
-Quantitative method: FP method-2θ angle peak: 103.078 deg (iodine), 136.847 deg (potassium)
・ Measurement time: 40 seconds

(4) Change in degree of polarization The polarizing plate with a retardation layer or the polarizing plate obtained in Examples and Comparative Examples was bonded to non-alkali glass to prepare a test sample. The degree of polarization of this test sample was measured by a conventional method, and this was used as the degree of initial polarization. Further, after subjecting the test sample to a reliability test (placed in an environment of 85 ° C. and 85% RH for 240 hours and then left in an environment of 23 ° C. and 55% RH for 24 hours), the degree of polarization is the same as described above. Was measured. The change in degree of polarization was calculated by the following formula.
Polarization degree change (%) = Initial polarization degree (%) -Polarization degree after reliability test (%)
Furthermore, it was evaluated according to the following criteria.
Good: Polarization degree change is less than 5.0% Poor: Polarization degree change is 5.0% or more

(5) Increase in reflectance The polarizing plates with retardation layers obtained in Examples and Comparative Examples were attached to non-alkali glass to prepare a test sample. This test sample is placed on a reflector having a reflectance of 80%, and a spectrophotometer (CM700D manufactured by Konica Minolta) is used to set the value at 550 nm as the reflectance (%) in SCI mode, and this is the initial reflection. It was a rate. Further, after subjecting the test sample to a reliability test (placed in an environment of 60 ° C. and 90% RH for 500 hours and then left in an environment of 23 ° C. and 55% RH for 24 hours), the reflectance is the same as described above. Was measured. The reflectance increase was calculated by the following formula.
Increased reflectance (%) = initial reflectance (%) -reflectance after reliability test (%)
Furthermore, it was evaluated according to the following criteria.
Good: Reflectance increase is less than 0.50% Acceptable: Reflectance increase is 0.50% or more and less than 1.00% Poor: Reflectance increase is 1.00% or more

(6) Metal corrosive (48 hours)
Wire a silver nanowire solution (manufactured by MERCK, nanowire size: diameter 115 nm, length 20 μm to 50 μm, solid content 0.5% isopropyl alcohol (IPA) solution) on one side of a 50 μm polyethylene terephthalate (PET) film. It was coated with a bar so that the wet film thickness was 15 μm, and dried in an oven at 100 ° C. for 5 minutes to form a silver nanowire coating film. Next, an overcoat solution (solid content) containing 99 parts of methyl isobutyl ketone (MIBK), 1 part of pentaerythritol tetraacrylate (PETA), and 0.03 part of a photopolymerization initiator (manufactured by BASF, product name "Irgacure 907"). Concentration: about 1%) was applied to the surface of the silver nanowire coating film using a wire bar so that the wet film thickness was 10 μm, and dried in an oven at 100 ° C. for 5 minutes. Next, the overcoat coating film was cured by irradiating with active energy rays to prepare a metal film having a composition of PET film / silver nanowire layer / overcoat layer (thickness 100 nm). This metal film was attached to a glass plate having a thickness of 0.5 mm using an adhesive (15 μm) to obtain a metal film / adhesive / glass plate laminate. When the resistance value of the obtained laminate was measured with a non-contact resistance measuring instrument (manufactured by Napuson, product name "EC-80"), it was 50Ω / □.

The polarizing plate with a retardation layer or the polarizing plate obtained in Examples and Comparative Examples was bonded to the surface of the overcoat layer of the metal film of the laminated body to prepare a test sample. The resistance value of this test sample was measured with a non-contact resistance measuring instrument and used as the initial resistance value. Further, after subjecting the test sample to a reliability test (placed in an environment of 85 ° C. and 85% RH for 48 hours and then left in an environment of 23 ° C. and 55% RH for 2 hours), the resistance value is the same as above. Was measured. The resistance value increase rate was calculated by the following formula. When the measured value (resistance value) exceeds the measurement limit (1000Ω / □) of the non-contact resistance measuring instrument, the measured value is assumed to be 1500Ω / □.
Resistance value increase rate (%) = {(resistance value after reliability test-initial resistance value) / initial resistance value} x 100
Furthermore, it was evaluated according to the following criteria.
Good: Resistance increase rate is less than 200% Bad: Resistance increase rate is 200% or more

(7) Metal corrosiveness (200 hours)
The polarizing plates with retardation layers obtained in Examples and Comparative Examples were bonded to the overcoat layer forming surface of the metal film of the laminate obtained in (2) to prepare a test sample. The resistance value of this test sample was measured with a non-contact resistance measuring instrument and used as the initial resistance value. Further, after subjecting the test sample to a reliability test (placed in an environment of 85 ° C. and 85% RH for 200 hours and then left in an environment of 23 ° C. and 55% RH for 2 hours), the resistance value is the same as above. Was measured. The resistance value increase rate was calculated by the following formula. When the measured value (resistance value) exceeds the measurement limit (1000Ω / □) of the non-contact resistance measuring instrument, the measured value is assumed to be 1500Ω / □.
Resistance value increase rate (%) = {(resistance value after reliability test-initial resistance value) / initial resistance value} x 100
Furthermore, it was evaluated according to the following criteria.
Excellent: Resistance increase rate is less than 200% Good: Resistance increase rate is 200% or more and less than 2000% Bad: Resistance increase rate is 2000% or more

[Example 1]
1. 1. Preparation of Polarizer As the thermoplastic resin base material, an amorphous isophthalic copolymerized polyethylene terephthalate film (thickness: 100 μm) having a long shape, a water absorption of 0.75%, and a Tg of about 75 ° C. was used. One side of the resin base material was corona-treated.
100 weight of PVA-based resin in which polyvinyl alcohol (degree of polymerization 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gosefimer Z410") are mixed at a ratio of 9: 1. A PVA aqueous solution (coating solution) was prepared by dissolving 13 parts by weight of potassium iodide in water.
The PVA aqueous solution was applied to the corona-treated surface of the resin base material and dried at 60 ° C. to form a PVA-based resin layer having a thickness of 13 μm to prepare a laminate.
The obtained laminate was uniaxially stretched at the free end 2.4 times in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds in an oven at 130 ° C. (aerial auxiliary stretching treatment).
Next, the laminate was immersed in an insolubilizing bath at a liquid temperature of 40 ° C. (an aqueous boric acid solution obtained by blending 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insolubilization treatment).
Next, in a dyeing bath having a liquid temperature of 30 ° C. (an aqueous iodine solution obtained by mixing iodine and potassium iodide in a weight ratio of 1: 7 with respect to 100 parts by weight of water), the polarizer finally obtained Immersion was carried out for 60 seconds while adjusting the concentration so that the simple substance transmittance (Ts) was 43.0% or more (dyeing treatment).
Then, it was immersed in a cross-linked bath at a liquid temperature of 40 ° C. (an aqueous boric acid solution obtained by blending 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with respect to 100 parts by weight of water) for 30 seconds. (Crossing treatment).
Then, while immersing the laminate in a boric acid aqueous solution (boric acid concentration 4.0% by weight, potassium iodide concentration 5% by weight) at a liquid temperature of 70 ° C., the rolls having different peripheral speeds are subjected to the longitudinal direction (longitudinal direction). The uniaxial stretching was performed so that the total stretching ratio was 5.5 times (underwater stretching treatment).
Then, the laminate was immersed in a washing bath at a liquid temperature of 20 ° C. (an aqueous solution obtained by blending 4 parts by weight of potassium iodide with 100 parts by weight of water) (cleaning treatment).
Then, while drying in an oven kept at 90 ° C., it was brought into contact with a heating roll made of SUS whose surface temperature was kept at 75 ° C. for about 2 seconds (dry shrinkage treatment). The shrinkage rate in the width direction of the laminated body by the drying shrinkage treatment was 5.2%.
In this way, a polarizer having a thickness of 5 μm was formed on the resin substrate.

2. Preparation of Polarizing Plate An HC-COP film as a protective layer was attached to the surface of the polarizer obtained above (the surface opposite to the resin substrate) via an ultraviolet curable adhesive. Specifically, the curable adhesive was coated so as to have a total thickness of 1.0 μm, and bonded using a roll machine. Then, UV light was irradiated from the protective layer side to cure the adhesive. The HC-COP film is a film in which a hard coat (HC) layer (thickness 2 μm) is formed on a cycloolefin (COP) film (manufactured by Nippon Zeon Corporation, product name “ZF12”, thickness 25 μm), and is a COP film. Was attached so that it was on the polarizer side. Next, the resin base material was peeled off to obtain a polarizing plate having a structure of a protective layer (HC layer / COP film) / adhesive layer / polarizer.

ポリエチレンテレフタレート（ＰＥＴ）フィルム（厚み３８μｍ）表面を、ラビング布を用いてラビングし、配向処理を施した。配向処理の方向は、偏光板に貼り合わせる際に偏光子の吸収軸の方向に対して視認側から見て１５°方向となるようにした。この配向処理表面に、上記液晶塗工液をバーコーターにより塗工し、９０℃で２分間加熱乾燥することによって液晶化合物を配向させた。このようにして形成された液晶層に、メタルハライドランプを用いて１ｍＪ/ｃｍ^２の光を照射し、当該液晶層を硬化させることによって、ＰＥＴフィルム上に液晶配向固化層Ａを形成した。液晶配向固化層Ａの厚みは２．５μｍ、面内位相差Ｒｅ（５５０）は２７０ｎｍであった。さらに、液晶配向固化層Ａは、ｎｘ＞ｎｙ＝ｎｚの屈折率分布を有していた。
塗工厚みを変更したこと、および、配向処理方向を偏光子の吸収軸の方向に対して視認側から見て７５°方向となるようにしたこと以外は上記と同様にして、ＰＥＴフィルム上に液晶配向固化層Ｂを形成した。液晶配向固化層Ｂの厚みは１．５μｍ、面内位相差Ｒｅ（５５０）は１４０ｎｍであった。さらに、液晶配向固化層Ｂは、ｎｘ＞ｎｙ＝ｎｚの屈折率分布を有していた。 3. 3. Preparation of First Oriented Solidified Layer and Second Oriented Solidified Layer Constituting the Phase Difference Layer With 10 g of polymerizable liquid crystal (manufactured by BASF: trade name "Pariocolor LC242", represented by the following formula) showing a nematic liquid crystal phase. , 3 g of a photopolymerization initiator (manufactured by BASF: trade name "Irgacure 907") for the polymerizable liquid crystal compound was dissolved in 40 g of toluene to prepare a liquid crystal composition (coating liquid).

The surface of a polyethylene terephthalate (PET) film (thickness 38 μm) was rubbed with a rubbing cloth and subjected to an orientation treatment. The direction of the orientation treatment was set to be 15 ° when viewed from the visual side with respect to the direction of the absorption axis of the polarizer when the polarizing plate was attached. The liquid crystal coating liquid was applied to the alignment-treated surface with a bar coater, and the liquid crystal compound was oriented by heating and drying at 90 ° C. for 2 minutes. ^{The liquid crystal layer thus formed was irradiated with light of 1 mJ / cm 2} using a metal halide lamp, and the liquid crystal layer was cured to form a liquid crystal oriented solidified layer A on the PET film. The thickness of the liquid crystal oriented solidified layer A was 2.5 μm, and the in-plane retardation Re (550) was 270 nm. Further, the liquid crystal oriented solidified layer A had a refractive index distribution of nx> ny = nz.
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 ° when viewed from the visual side with respect to the direction of the absorber's absorption axis. A liquid crystal oriented solidified layer B was formed. The thickness of the liquid crystal oriented solidified layer B was 1.5 μm, and the in-plane retardation Re (550) was 140 nm. Further, the liquid crystal oriented solidified layer B had a refractive index distribution of nx> ny = nz.

4. Formation of retardation layer 2. On the polarizer surface of the polarizing plate obtained in 3. above. The liquid crystal oriented solidified layer A and the liquid crystal oriented solidified layer B obtained in the above were transferred in this order. At this time, the angle formed by the absorption axis of the polarizer and the slow axis of the liquid crystal oriented solidified layer A is 15 °, and the angle formed by the absorption axis of the polarizer and the slow axis of the liquid crystal oriented solidified layer B is 75 °. Transfer (bonding) was performed in this way. In addition, each transfer (bonding) is performed in the above 2. This was done via the ultraviolet curable adhesive (thickness 1.0 μm) used in. In this way, the protective layer (HC layer / COP film) / adhesive layer / polarizer / adhesive layer / retardation layer (first liquid crystal oriented solidified layer / adhesive layer / second liquid crystal oriented solidified layer). A laminated body having the above-mentioned structure was produced.

5. Preparation of polarizing plate with retardation layer 20 parts of acrylic resin (manufactured by Kusumoto Kasei Co., Ltd., product name "B-811", Tg: 110 ° C., Mw: 40000) was dissolved in 80 parts of methyl ethyl ketone, and a resin solution (20%) was used. Got This resin solution is applied to the above 4. The coating film was applied to the surface of the second liquid crystal oriented solidified layer of the laminate obtained in the above method using a wire bar, and the coating film was dried at 60 ° C. for 5 minutes to form a solidified coating film of a resin organic solvent solution. An iodine permeation inhibitory layer (thickness 0.5 μm) was formed. Next, an adhesive layer (thickness 15 μm) is provided on the surface of the iodine permeation suppressing layer, and a protective layer (HC layer / COP film) / adhesive layer / polarizer / adhesive layer / retardation layer (first liquid crystal alignment solidification layer) is provided. A polarizing plate with a retardation layer having the constitution of / adhesive layer / second liquid crystal oriented solidified layer) / iodine permeation suppressing layer / adhesive layer was obtained. The total thickness of the obtained polarizing plate with a retardation layer was 39.5 μm. The obtained polarizing plate with a retardation layer was subjected to the evaluations (4) to (7) above. Further, regarding metal corrosiveness, it was compared with Comparative Example 1 (described later) in which the iodine permeation suppressing layer was not formed. The results are shown in Table 1.

[Example 2]
Methyl methacrylate (MMA, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "methyl methacrylate monomer") 97.0 parts, 3.0 parts of copolymerization monomer represented by the above general formula (1e), polymerization initiation 0.2 part of the agent (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "2,2'-azobis (isobutyronitrile)") was dissolved in 200 parts of toluene. Next, a polymerization reaction was carried out for 5.5 hours while heating at 70 ° C. in a nitrogen atmosphere to obtain a boron-containing acrylic resin solution (solid content concentration: 33%). The obtained boron-containing acrylic polymer had a Tg of 110 ° C. and a Mw of 80,000. The retardation layer was the same as in Example 1 except that this boron-containing acrylic polymer was used instead of the acrylic resin "B-811" and the thickness of the iodine permeation suppressing layer was 0.3 μm. A polarizing plate with a plate was prepared. 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.

[Example 3]
A polarizing plate with a retardation layer was produced in the same manner as in Example 2 except that the thickness of the iodine permeation suppressing layer was 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.

[Example 4]
Examples except that a thermoplastic epoxy resin (manufactured by Mitsubishi Chemical Co., Ltd., trade name "jER (registered trademark) 1256B40", Tg: 100 ° C., Mw: 45000) was used instead of the acrylic resin "B-811". A polarizing plate with a retardation layer was produced in the same manner as in 1. 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.

[Example 5]
A thermoplastic epoxy resin (manufactured by Mitsubishi Chemical Co., Ltd., trade name "jER (registered trademark) YX7200B35", Tg: 150 ° C., Mw: 30000) was used instead of the acrylic resin "B-811", and iodine. A polarizing plate with a retardation layer was produced in the same manner as in Example 1 except that the thickness of the permeation suppression layer was 0.3 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.

[Example 6]
A polarizing plate with a retardation layer was produced in the same manner as in Example 5 except that the thickness of the iodine permeation suppressing layer was 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.

[Example 7]
Instead of the acrylic resin "B-811", 15 parts of "B-811" and 85 parts of thermoplastic epoxy resin (manufactured by Mitsubishi Chemical Co., Ltd., trade name "jER (registered trademark) YX6954BH30") (solid content conversion) A polarizing plate with a retardation layer was produced in the same manner as in Example 1 except that the above blend was used. The Tg of the blend was 125 ° C. and the Mw was 38,000. 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.

[Example 8]
Example 1-2. The resin blend used in Example 7 was applied and dried on the polarizer side of the polarizing plate having the constitution of the protective layer (HC layer / COP film) / adhesive layer / polarizer obtained in the above, and the resin was organic. An iodine permeation inhibitory layer (thickness 0.5 μm) formed as a solidified coating film of the solvent solution was formed. The liquid crystal oriented solidified layer A and the liquid crystal oriented solidified layer B are transferred to the surface of the iodine permeation suppressing layer in this order in the same manner as in Example 1, and the protective layer (HC layer / COP film) / adhesive layer / polarizer / iodine permeation A polarizing plate with a retardation layer having a structure of an inhibitory layer / adhesive layer / retardation layer (first liquid crystal alignment solidification layer / adhesive layer / second liquid crystal alignment solidification layer) / adhesive layer was obtained. 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.

[Example 9]
Lamination having a protective layer (HC layer / COP film) / adhesive layer / polarizer / iodine permeation suppressing layer in the same manner as in Example 8 except that the boron-containing acrylic polymer in Example 2 was used. The body was made. Next, a blend of 15 parts of the boron-containing acrylic polymer and 85 parts (solid content equivalent) of the thermoplastic epoxy resin (manufactured by Mitsubishi Chemical Co., Ltd., trade name "jER (registered trademark) YX6954BH30") in Example 2 was used. Protective layer (HC layer / COP film) / adhesive layer / polarizer / iodine permeation suppression layer / adhesive layer / retardation layer (first liquid crystal oriented solidifying layer / adhesion) in the same manner as in Example 1 except for the above. A polarizing plate with a retardation layer having a structure of an agent layer / a second liquid crystal oriented solidified layer) / an iodine permeation suppressing layer / an adhesive layer was obtained. The total thickness of the obtained polarizing plate with a retardation layer was 40 μm. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

[Example 10]
Fifteen parts of the boron-containing acrylic polymer obtained in Example 2 and a thermoplastic epoxy resin (on the iodine permeation suppressing layer provided between the polarizing element and the retardation layer and adjacent to the polarizing element). A polarizing plate with a retardation layer was obtained in the same manner as in Example 9 except that a blend with 85 parts (solid content equivalent) of Mitsubishi Chemical Co., Ltd., trade name "jER (registered trademark) YX6954BH30") was used. .. The total thickness of the obtained polarizing plate with a retardation layer was 40 μm. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

[Example 11]
The iodine permeation suppressing layer formed between the polarizer and the retardation layer at a position adjacent to the polarizer is placed between the polarizer and the retardation layer at a position adjacent to the retardation layer. Protective layer (HC layer / COP film) / adhesive layer / polarizer / adhesive layer / iodine permeation suppression layer / retardation layer (first liquid crystal oriented solidified layer) in the same manner as in Example 10 except that it was formed. A polarizing plate with a retardation layer having the constitution of / adhesive layer / second liquid crystal alignment solidification layer) / iodine permeation suppression layer / pressure-sensitive adhesive layer was obtained. The total thickness of the obtained polarizing plate with a retardation layer was 40 μm. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

[Example 12]
Similar to Example 9, the protective layer (HC) is similar to that of Example 11 except that an iodine permeation suppressing layer is further formed between the polarizer and the retardation layer at a position adjacent to the polarizer. Layer / COP film) / Adhesive layer / Polarizer / Iodine permeation inhibitory layer / Adhesive layer / Iodine permeation inhibitory layer / Phase difference layer (first liquid crystal oriented solidified layer / adhesive layer / second liquid crystal oriented solidified layer) ) / A polarizing plate with a retardation layer having a structure of an iodine permeation suppressing layer / an adhesive layer was obtained. The total thickness of the obtained polarizing plate with a retardation layer was 40.5 μm. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

[Comparative Example 1]
A polarizing plate with a retardation layer was produced in the same manner as in Example 1 except that the iodine permeation suppressing 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.

[Comparative Example 2]
A retardation layer in the same manner as in Example 1 except that an acrylic resin "B-723" (manufactured by Kusumoto Kasei Co., Ltd., Tg: 54 ° C., Mw: 200,000) was used instead of the acrylic resin "B-811". A polarizing plate with a polarizing plate was prepared. 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.

[Comparative Example 3]
Uses a photocurable epoxy resin (manufactured by Mitsubishi Chemical Co., Ltd., trade name "jER (registered trademark) 828", and San Appro "CPI100P" as a photopolymerization initiator) instead of the acrylic resin "B-811". A polarizing plate with a retardation layer was produced in the same manner as in Example 1 except for the above. 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.

[Comparative Example 4]
Same as in Example 1 except that a PVA resin (manufactured by Mitsubishi Chemical Corporation, trade name "Gosenol Z200", Tg: 80 ° C., Mw: 8800) was used instead of the acrylic resin "B-811". A polarizing plate with a retardation layer was produced. 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.

[Reference example 1]
1. 1. Preparation of Polarizing Plate A polarizing plate having a protective layer (HC layer / COP film) / polarizing element was obtained in the same manner as in Example 1.

2. Preparation of retardation film constituting the retardation layer 2-1. Polymerization of polyester carbonate-based resin Polymerization was carried out using a batch polymerization apparatus consisting of two vertical reactors equipped with a stirring blade and a reflux condenser controlled at 100 ° C. Bis [9- (2-phenoxycarbonylethyl) fluorene-9-yl] 29.60 parts by mass (0.046 mol) of methane, 29.21 parts by mass (0.200 mol) of isosorbide (ISB), spiroglycol (SPG) 42 .28 parts by weight (0.139 mol), diphenyl carbonate (DPC) 63.77 parts by weight (0.298 mol) and calcium acetate monohydrate 1.19 × ^{10 -2} parts by weight as a catalyst (6.78 × 10 ^{- 5} mol) was charged. After substituting nitrogen under reduced pressure in the reactor, heating was performed with a heat medium, and stirring was started when the internal temperature reached 100 ° C. The internal temperature was brought to 220 ° C. 40 minutes after the start of the temperature rise, and the depressurization was started at the same time as controlling to maintain this temperature, and the temperature was adjusted to 13.3 kPa 90 minutes after reaching 220 ° C. The phenol vapor produced as a by-product of the polymerization reaction was guided to a reflux condenser at 100 ° C., the monomer component contained in a small amount in the phenol vapor was returned to the reactor, and the uncondensed phenol vapor was guided to a condenser at 45 ° C. for recovery. Nitrogen was introduced into the first reactor and the pressure was once restored to atmospheric pressure, and then the oligomerized reaction solution in the first reactor was transferred to the second reactor. Then, the temperature rise and depressurization in the second reactor were started, and the internal temperature was 240 ° C. and the pressure was 0.2 kPa in 50 minutes. Then, the polymerization was allowed to proceed until the stirring power became a predetermined value. When the predetermined power was reached, nitrogen was introduced into the reactor to repressurize, the produced polyester carbonate-based resin was extruded into water, and the strands were cut to obtain pellets.

2-2. Preparation of retardation film After vacuum-drying the obtained polyester carbonate resin (pellets) at 80 ° C for 5 hours, a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder set temperature: 250 ° C), T-die (width 200 mm) , Set temperature: 250 ° C.), chill roll (set temperature: 120 to 130 ° C.), and a film forming apparatus equipped with a winder was used to prepare a long resin film having a thickness of 135 μm. The obtained elongated 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 having a thickness of 53 μm. The Re (550) of the obtained retardation film was 141 nm, the Re (450) / Re (550) was 0.82, and the Nz coefficient was 1.12.

3. 3. Fabrication of polarizing plate with retardation layer 1. On the polarizer surface of the polarizing plate obtained in 2. above. The retardation film obtained in (1) was bonded via an acrylic pressure-sensitive adhesive (thickness: 5 μm). At this time, the absorption axis of the polarizer and the slow axis of the retardation film were bonded so as to form an angle of 45 °. Further, the same pressure-sensitive adhesive layer as in Example 1 was provided on the surface of the retardation layer. In this way, a polarizing plate with a retardation layer having a structure of a protective layer / adhesive layer / polarizer / pressure-sensitive adhesive layer / retardation layer (stretched film of resin film) / pressure-sensitive adhesive layer was obtained. The total thickness of the obtained polarizing plate with a retardation layer was 91 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.

[Example 13]
A polarizing plate having a structure of a protective layer (HC layer / COP film) / adhesive layer / polarizer / iodine permeation suppressing layer / adhesive layer in the same manner as in Example 1 except that a retardation layer was not formed. Got The total thickness of the obtained polarizing plate was 33.5 μm. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are shown in Tables 1 and 2. Since this example is a polarizing plate and has a different configuration from the polarizing plate with a retardation layer, the metal corrosiveness was not compared with that of Comparative Example 1.

[evaluation]
As is clear from Table 1, the polarizing plate with a retardation layer and the polarizing plate according to the embodiment of the present invention form a predetermined iodine permeation suppressing layer so that the iodine presence index of the pressure-sensitive adhesive layer is set to a predetermined value or less. , The change in polarization degree in a high temperature and high humidity environment can be reduced, and it has excellent durability. Further, the polarizing plate with a retardation layer and the polarizing plate according to the embodiment of the present invention can remarkably suppress metal corrosiveness and an increase in reflectance in a high temperature and high humidity environment. Further, as is clear from Reference Example 1, such a change in polarization degree, an increase in reflectance, and metal corrosiveness are problems peculiar to a very thin polarizing plate with a retardation layer and a polarizing plate. As is clear from a comparison between Example 1 and Example 13, it can be seen that the presence or absence of the liquid crystal oriented solidified layer (very thin retardation layer) does not substantially affect the effect of the present invention.

As is clear from Table 2, the polarizing plate with a retardation layer of Examples 9 to 12 of the present invention contains two or three layers of iodine permeation suppression layers for a long time (200 hours) in a high temperature and high humidity environment. ) Even when it is thrown in, metal corrosiveness can be remarkably suppressed. Therefore, it can be seen that the polarizing plates with retardation layers of Examples 9 to 12 of the present invention can remarkably suppress the corrosion of metal members when applied to an image display device.

The polarizing plate of the present invention is suitably used for a liquid crystal display device, an organic EL display device, and an inorganic EL display device. The polarizing plate with a retardation layer of the present invention is suitably used as a circular polarizing plate for a liquid crystal display device, an organic EL display device, and an inorganic EL display device.

10 Polarizing plate 11 Polarizer 12 Protective layer 20 Phase difference layer 30 Adhesive layer 40 Iodine permeation suppression layer 100 Polarizing plate with retardation layer 101 Polarizing plate with retardation layer 102 Polarizing plate with retardation layer 103 Polarizing plate with retardation layer 104 Polarizing plate with retardation layer 105 Polarizing plate with retardation layer

Claims (12)

A polarizing plate having a polarizer, an iodine permeation suppressing layer, and a pressure-sensitive adhesive layer in this order, and the iodine presence index of the pressure-sensitive adhesive layer is 0.050 or less. The polarizing plate according to claim 1, wherein the iodine permeation suppressing layer is a solidified product or a thermosetting product of a coating film of a resin organic solvent solution. The polarizing plate according to claim 2, wherein the glass transition temperature of the resin constituting the iodine permeation suppressing layer is 85 ° C. or higher, and the weight average molecular weight Mw is 25000 or higher. The polarizing plate according to claim 1, wherein two or more layers of the iodine permeation suppressing layer are provided between the polarizing element and the pressure-sensitive adhesive layer. The polarizing plate according to any one of claims 1 to 4, wherein the iodine permeation suppressing layer has a thickness of 0.05 μm to 10 μm. The resin constituting the iodine permeation suppressing layer contains more than 50 parts by weight (meth) acrylic monomer and a monomer represented by the formula (1) having more than 0 parts by weight and less than 50 parts by weight. The polarizing plate according to any one of claims 1 to 5, which comprises a copolymer obtained by polymerizing a monomer mixture:

(In the formula, X is a group consisting of a vinyl group, a (meth) acrylic 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. Represents a functional group containing at least one reactive group selected, and R ¹ and R ² each independently have a hydrogen atom, an aliphatic hydrocarbon group which may have a substituent, and a substituent. It represents an aryl group which may be used, or a heterocyclic group which may have a substituent, and R ¹ and R ² may be linked to each other to form a ring). The polarizing plate according to any one of claims 1 to 6 and a retardation layer arranged between the polarizing element and the pressure-sensitive adhesive layer.
The retardation layer is an orientation-solidified layer of a liquid crystal compound having a circularly polarized light function or an elliptically polarized light function.
Polarizing plate with retardation layer. The retardation layer is a single layer
The Re (550) of the retardation layer is 100 nm to 190 nm.
The angle formed by the slow axis of the retardation layer and the absorption axis of the polarizer is 40 ° to 50 °.
The polarizing plate with a retardation layer according to claim 7. The retardation layer has a laminated structure of an orientation-solidified layer of a first liquid crystal compound and an orientation-solidification layer of a second liquid crystal compound.
The Re (550) of the oriented solidification 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 oriented 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 °.
The polarizing plate with a retardation layer according to claim 7. The polarizing plate with a retardation layer according to any one of claims 7 to 9, wherein the total thickness is 60 μm or less. An image display device comprising the polarizing plate according to any one of claims 1 to 6 or the polarizing plate with a retardation layer according to any one of claims 7 to 10. The image display device according to claim 11, which is an organic electroluminescence display device or an inorganic electroluminescence display device.

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