TWI823031B - Polarizing plate with retardation layer and image display device using the same - Google Patents

Abstract

The present invention provides a thin polarizing plate with a retardation layer. When used in an image display device, the thin polarizing plate with a retardation layer has good reliability in a high temperature and high humidity environment and can suppress an increase in reflectivity. The polarizing plate with a retardation layer of the present invention has a polarizing plate including a polarizer, a retardation layer and an adhesive layer in order from the viewing side. The phase difference layer is a directionally solidified layer of a liquid crystal compound with circular polarization function or eccentric polarization function. A polarizing plate with a retardation layer is provided with an iodine transmission inhibition layer between the polarizer and the adhesive layer. The iodine transmission inhibition layer is a cured or thermally cured product of a coating film of an organic solvent solution of resin; the iodine transmission inhibition layer The iodine absorption index is below 0.015.

Description

Polarizing plate with retardation layer and image display device using the same

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

In recent years, image display devices represented by liquid crystal display devices and electroluminescence (EL) display devices (eg, organic EL display devices, inorganic EL display devices) have rapidly become popular. Typical image display devices use polarizing plates and phase difference plates. In practical applications, polarizing plates with a retardation layer in which a polarizing plate and a retardation plate are integrated are widely used (for example, Patent Document 1). Recently, as the demand for thinner image display devices has increased, the need for retardation layers has increased. The demand for thinner polarizing plates has also increased. In order to reduce the thickness of the polarizing plate with the retardation layer, thinning (or omission) of the polarizer protective layer, which has a large influence on the thickness, and thinning of the retardation film have been promoted. However, when a thin polarizing plate with a retardation layer is applied to an image display device, the reliability may be insufficient in a high-temperature and high-humidity environment. More specifically, a polarizing plate with a retardation layer can typically be used as an anti-reflection film, but in high temperature and high humidity environments, the reflectivity of an image display device may increase. Furthermore, when a thin polarizing plate with a retardation layer is applied to an image display device, the metal components of the image display device (such as electrodes, sensors, wiring, and metal layers) may corrode. Prior technical literature patent documents

Patent Document 1: Japanese Patent No. 3325560

The problem to be solved by the invention The present invention is made to solve the above-mentioned conventional problems, and its main purpose is to provide a thin polarizing plate with a retardation layer. When the thin polarizing plate with a retardation layer is used in an image display device, it performs well in a high-temperature and high-humidity environment. It has good reliability and can suppress the increase of reflectivity.

Means for Solving the Problems The polarizing plate with a retardation layer of the present invention has a polarizing plate including a polarizer, a retardation layer and an adhesive layer in order from the viewing side. The retardation layer has a circular polarization function or an elliptical polarization function. Functional directionally solidified layer of liquid crystal compound. The polarizing plate with the retardation layer is provided with an iodine transmission inhibition layer between the polarizer and the adhesive layer. The iodine transmission inhibition layer is a cured or thermally cured product of a coating film of an organic solvent solution of resin; the iodine transmission inhibition layer is The iodine absorption index through the inhibition layer is 0.015 or less. In one embodiment, the iodine transmission suppressing layer is provided between the polarizer and the retardation layer. In another embodiment, the iodine transmission inhibiting layer is provided between the retardation layer and the adhesive layer. In one embodiment, two or more layers of the iodine transmission inhibiting layer are provided between the polarizer and the adhesive layer. In one embodiment, the potassium absorption index of the iodine permeation inhibiting layer is 0.015 or less. In one embodiment, the glass transition temperature of the resin constituting the iodine transmission inhibiting layer is 85° C. or higher, and the weight average molecular weight Mw is 25,000 or higher. In one embodiment, the resin constituting the iodine transmission inhibiting layer includes a copolymer obtained by polymerizing a monomer mixture, and the monomer mixture includes more than 50 parts by weight of a (meth)acrylic monomer and more than 0 Parts by weight and less than 50 parts by weight of the monomer represented by formula (1): [Chemical Formula 1] (In the formula, At least one reactive group in the group consisting of an ether group, an epoxy group, an oxetanyl group, a hydroxyl group, an amine group, an aldehyde group and a carboxyl group. R ¹ and R ² each independently represent a hydrogen atom and may be substituted. The base is an aliphatic hydrocarbon group, an aryl group that may have a substituent, or a heterocyclic group that may have a substituent, and R ¹ and R ² may be connected to each other to form a ring). In one embodiment, the above-mentioned retardation layer is a single layer, and the Re(550) of the retardation layer is 100nm~190nm, and the angle formed by the slow axis of the retardation layer and the absorption axis of the above-mentioned polarizer is 40°~ 50°. In one embodiment, the retardation layer has a laminated structure of a directionally solidified layer of a first liquid crystal compound and a directionally solidified layer of a second liquid crystal compound; Re (550) of the directionally solidified layer of the first liquid crystal compound is 200 nm to 300 nm. , and the angle formed by its slow axis and the absorption axis of the polarizer is 10°~20°; the Re(550) of the orientationally solidified layer of the second liquid crystal compound is 100nm~190nm, and its slow axis is aligned with the angle of the polarizer. The angle formed by the absorption axis is 70°~80°. In one embodiment, the above-mentioned polarizing plate with a retardation layer further has another retardation layer between the above-mentioned retardation layer and the above-mentioned adhesive layer, and the refractive index characteristics of the other retardation layer show that nz>nx=ny relationship. In one embodiment, the polarizing plate with a retardation layer further has a conductive layer or an isotropic base material with a conductive layer between the iodine transmission inhibiting layer and the adhesive layer. In one embodiment, the total thickness of the polarizing plate with the retardation layer is 60 μm or less. According to another aspect of the present invention, an image display device is provided. This image display device includes the above-mentioned polarizing plate with a retardation layer. In one embodiment, the image display device is an organic electroluminescent display device or an inorganic electroluminescent display device.

Invention effect According to an embodiment of the present invention, by disposing an iodine transmission suppressing layer with a predetermined iodine absorption index at a predetermined position of the thin polarizing plate with a retardation layer, the polarizing plate with a retardation layer can be suppressed when the polarizing plate with a retardation layer is applied to an image display device. The reflectivity increases in high temperature and high humidity environments.

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

(Definition of terms and symbols) The definitions of terms and symbols in this manual are as follows. (1)Refractive index (nx, ny, nz) "nx" is the refractive index in the direction where the in-plane refractive index is maximum (i.e., the slow axis direction), "ny" is the refractive index in the direction orthogonal to the slow axis in the plane (i.e., the fast axis direction), and " nz" is the refractive index in the thickness direction. (2) In-plane phase difference (Re) "Re(λ)" is the in-plane phase difference measured with light of wavelength λnm at 23°C. For example, "Re(550)" is the in-plane phase difference measured using light with a wavelength of 550 nm at 23°C. Re(λ) can be obtained by the formula: Re(λ)=(nx-ny)×d when the thickness of the layer (film) is d(nm). (3) Phase difference in thickness direction (Rth) "Rth(λ)" is the phase difference in the thickness direction measured with light of wavelength λnm at 23°C. For example, "Rth(550)" is the phase difference in the thickness direction measured at 23°C using light with a wavelength of 550 nm. Rth(λ) can be obtained by the formula: Rth(λ)=(nx-nz)×d when the layer (film) thickness is d(nm). (4)Nz coefficient The Nz coefficient can be obtained by Nz=Rth/Re. (5)Angle When an angle is mentioned in this specification, the angle includes both clockwise and counterclockwise directions relative to the reference direction. So, for example, "45°" means ±45°.

A. Overall composition of polarizing plate with retardation layer 1A is a schematic cross-sectional view of a polarizing plate with a retardation layer according to one embodiment of the present invention; FIG. 1B 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 100 and 101 with retardation layers in FIGS. 1A and 1B each have a polarizing plate 10, a retardation layer 20 and an adhesive layer 30 in order from the viewing side. The polarizing plate 10 representatively includes a polarizing element 11 and a protective layer 12 disposed on the viewing side of the polarizing element 11 . Another protective layer (not shown) may also be provided on the side of the polarizer 11 opposite to the viewing side (protective layer 12) according to the purpose. The retardation layer 20 is a directionally solidified layer of a liquid crystal compound having a circular polarization function or an elliptical circular polarization function (hereinafter sometimes simply referred to as a liquid crystal directionally solidified layer). The adhesive layer 30 is provided as the outermost layer, and the polarizing plate with the retardation layer can be attached to the image display device (essentially an image display unit).

In the embodiment of the present invention, an iodine transmission inhibiting layer 40 is provided between the polarizer 11 and the adhesive layer 30 . The iodine transmission inhibition layer 40 can be disposed between the polarizer 11 and the retardation layer 20 (that is, adjacent to the polarizer 11) as shown in FIG. 1A, or can be disposed between the retardation layer 20 and the adhesive layer 30 as shown in FIG. 1B. between. When the iodine transmission inhibition layer is disposed between the polarizer and the retardation layer (especially when the iodine transmission inhibition layer is adjacent to the polarizer), iodine can be inhibited from moving away from the polarizer in a high temperature and high humidity environment, thereby improving reliability. The advantages. When the iodine transmission inhibition layer is placed between the retardation layer and the adhesive layer (especially when the iodine transmission inhibition layer is adjacent to the adhesive layer), it can also prevent components other than iodine that may affect metal corrosion (such as ultraviolet rays) The residual monomer components and photoinitiator decomposition products in the hardened adhesive move into the adhesive, which has the advantage of further improving the metal corrosion inhibition effect.

In a polarizing plate with a retardation layer, two or more iodine transmission inhibiting layers can also be provided between the polarizer and the adhesive layer (for example, Figure 4 and Figure 5). By having the polarizing plate with the retardation layer having two or more iodine transmission inhibiting layers, when the polarizing plate with the retardation layer is used in an image display device, the corrosion of metal components can be significantly inhibited.

In the polarizing plate with a retardation layer shown in Figure 4, two layers of iodine transmission inhibition layers are provided between the polarizer and the adhesive layer. In the example shown in FIG. 4 , two iodine transmission inhibition layers are provided between the polarizer 11 and the retardation layer 20 and between the retardation layer 20 and the adhesive layer 30 . In one embodiment, the iodine transmission inhibiting layer is disposed adjacent to the polarizer. In another embodiment, the iodine transmission inhibiting layer is provided adjacent to the retardation layer. "Adjacent" in this specification means direct lamination without passing through an adhesive layer or the like.

In the polarizing plate with a retardation layer shown in Figure 5, three layers of iodine transmission inhibition layers are provided between the polarizer and the adhesive layer. In the example shown in FIG. 5 , two iodine transmission inhibiting layers are provided between the polarizer 11 and the retardation layer 20 , and one layer is provided between the retardation layer 20 and the adhesive layer 30 . One of the two iodine transmission suppressing layers between the polarizer 11 and the retardation layer 20 is disposed adjacent to the polarizer, and the other is disposed adjacent to the retardation layer.

In the polarizing plate with a retardation layer, the iodine transmission inhibiting layer may also be 4 or more layers (for example, 4 layers, 5 layers, or 6 layers). The greater the amount of iodine that penetrates the inhibition layer, the greater the metal corrosion inhibition effect. The number of iodine transmission inhibition layers can be set by taking into account cost, manufacturing efficiency, layer thickness of the polarizing plate with the retardation layer, etc.

The iodine absorption index of the iodine permeation inhibition layer is 0.015 or less. By disposing the iodine transmission inhibiting layer at a predetermined position of the polarizing plate with a retardation layer, when the polarizing plate with a retardation layer is applied to an image display device, the iodine in the polarizer can be significantly inhibited from moving to the image display. device (essentially an image display unit). As a result, when the polarizing plate with the retardation layer is applied to an image display device, the decrease in reliability caused by iodine in a high-temperature and high-humidity environment can be suppressed, thereby suppressing an increase in reflectivity. Furthermore, the potassium absorption index of the iodine permeation inhibiting layer is preferably 0.015 or less. As a result, since the iodine transmission suppressing layer has not only an iodine absorption index below a predetermined value but also a potassium absorption index below a predetermined value, the decrease in reliability caused by iodine in a high temperature and high humidity environment can be further suppressed, and therefore the increase in reflectivity can be further suppressed. .

The above-mentioned effect is a unique effect of a thin polarizing plate with a retardation layer (representing a polarizing plate with a retardation layer in which the upper retardation layer is a liquid crystal orientation solidification layer). That is, the inventors of the present invention have newly discovered the following problem: when a thin polarizing plate with a retardation layer is applied to an image display device, the reflectance may increase in a high-temperature and high-humidity environment, and it is understood that the problem is caused by Caused by iodine. After trial and error, it was found that an iodine transmission inhibition layer with the above-mentioned iodine absorption index can be used as a means to prevent iodine from moving to an image display device (essentially an image display unit), and thus the present invention was completed. In other words, the above-mentioned effects will solve new problems that were unknown in the past, and are truly unexpected and excellent effects. In addition, as will be described later, the iodine transmission suppressing layer can be formed very thin, and by providing the iodine transmission suppressing layer, the protective layer on the side opposite to the viewing side can be omitted, so the synergistic effect of these can also be helpful Further thinning of polarizing plates with retardation layers. In addition, the iodine transmission inhibiting layer may also have the effect of significantly inhibiting corrosion of metal components (eg, electrodes, sensors, wiring, metal layers) of the image display device.

As shown in FIG. 2 , the polarizing plate 102 with a retardation layer in another embodiment may also be provided with another retardation layer 50 and/or a conductive layer or an isotropic base material 60 with a conductive layer. Another retardation layer 50 can be typically provided between the retardation layer 20 and the adhesive layer 30 (ie, outside the retardation layer 20). The refractive index characteristics of another phase difference layer representative show the relationship nz>nx=ny. Representatively, the conductive layer or the isotropic substrate 60 with the conductive layer can be disposed between the iodine transmission inhibition layer 40 and the adhesive layer 30 (ie, outside the iodine transmission inhibition layer 40). Another phase difference layer 50 and a conductive layer or an isotropic substrate 60 with a conductive layer are arranged sequentially from the phase difference layer 20 side. In the example of the figure, the iodine transmission suppressing layer 40, the phase difference layer 20, another phase difference layer 50, and the conductive layer or the isotropic base material 60 with the conductive layer are provided in this order from the viewing side, but as long as Another phase difference layer 50 is provided between the phase difference 20 and the adhesive layer 30, and the conductive layer or the isotropic substrate 60 with the conductive layer is provided between the iodine transmission inhibition layer 40 and the adhesive layer 30. Use any appropriate configuration sequence. The other phase difference layer 50 and the conductive layer or the isotropic substrate 60 with the conductive layer represent any of the above layers that can be provided as needed, and any one or both of them can be omitted. In addition, for convenience, the phase difference layer 20 may be called a first phase difference layer, and the other phase difference layer 50 may be called a second phase difference layer. When a conductive layer or an isotropic substrate with a conductive layer can be provided, the polarizing plate with a phase difference layer can be applied to a so-called touch sensor integrated between an image display unit (such as an organic EL unit) and the polarizing plate. Inner touch panel type input display device. In the embodiment of the present invention, by arranging the conductive layer or the isotropic base material 60 with the conductive layer outside the iodine transmission inhibiting layer 40, corrosion of the conductive layer can be significantly suppressed.

As mentioned above, the first retardation layer 20 is a liquid crystal alignment solidified layer. The first retardation layer 20 may be a single layer as shown in FIG. 1A, FIG. 1B and FIG. 2, or may have a laminated structure of the first liquid crystal orientation solidified layer 21 and the second liquid crystal orientation solidified layer 22 as shown in FIG. 3. .

The above-mentioned embodiments may be combined appropriately, and changes evident in the industry may be added to the constituent elements of the above-mentioned embodiments. For example, the second retardation layer 50 and/or the conductive layer or the isotropic substrate 60 with the conductive layer can be provided on the polarizing plate 101 with a retardation layer in FIG. 1B ; the polarizing plate 101 with a retardation layer in FIG. 1B The retardation layer 20 may also have a 2-layer structure as shown in Figure 3; the second retardation layer 50 and/or a conductive layer or an isotropic base with a conductive layer may be provided on the polarizing plate 103 with a retardation layer in Figure 3. Material 60; the iodine transmission inhibition layer 40 of the polarizing plate 102 with a retardation layer in FIG. 2 can also be disposed between the retardation layer 20 and the conductive layer or the isotropic base material 60 with the conductive layer.

The polarizing plate with a retardation layer according to the embodiment of the present invention may further include other retardation layers. The optical properties (such as refractive index properties, in-plane phase difference, Nz coefficient, photoelastic coefficient), thickness, arrangement position, etc. of other retardation layers can be appropriately set according to the purpose.

The polarizing plate with a retardation layer according to the embodiment of the present invention may be in the form of a single sheet or a strip. The term "elongated shape" in this specification means an elongated shape with a length that is sufficiently long relative to the width. For example, it includes an elongated shape with a length that is 10 times or more relative to the width, and preferably an elongated shape with a length that is 20 times or more. The long polarizing plate with retardation layer can be rolled into a roll.

The total thickness of the polarizing plate with the retardation layer should be 60µm or less, more preferably 55µm or less, more preferably 50µm or less, especially 40µm or less. The lower limit of the total thickness may be, for example, 28 µm. According to the embodiment of the present invention, it is possible to realize the extremely thin polarizing plate with a retardation layer as described above, and even when such an extremely thin polarizing plate with a retardation layer is applied to an image display device, it is possible to suppress In high-temperature and high-humidity environments, iodine reduces reliability, thereby suppressing an increase in reflectivity. And it can significantly inhibit the corrosion of metal components (such as electrodes, sensors, wiring, metal layers) of the image display device. In addition, the polarizing plate with the retardation layer can have extremely excellent flexibility and bending durability. Therefore, the polarizing plate with a retardation layer can be particularly suitably applied to a curved image display device and/or a bendable or foldable image display device. In addition, the total thickness of the polarizing plate with a retardation layer refers to the polarizing plate, the retardation layer (the first retardation layer and the second retardation layer when there is a second retardation layer), the iodine transmission suppression layer and The total thickness of the adhesive layer or adhesive layer used to laminate these layers (that is, the total thickness of the polarizing plate with the retardation layer does not include the conductive layer or the isotropic substrate 60 with the conductive layer, and the adhesive layer 30 and the thickness of the peelable film that can temporarily adhere to its surface).

In practical applications, it is preferable that a release film is temporarily adhered to the surface of the adhesive layer 30 before the polarizing plate with the retardation layer is used. By temporarily adhering the release film, a roll of a polarizing plate with a retardation layer can be formed while protecting the adhesive layer.

The components of the polarizing plate with a retardation layer will be described in more detail below. In addition, the adhesive layer 30 can adopt a structure well known in the industry, so the detailed structure of the adhesive layer is omitted.

B.Polarizing plate B-1.Polarizer Polarizers are typically made of polyvinyl alcohol (PVA) resin films containing dichroic substances. The thickness of the polarizer should be 1µm~8µm, 1µm~7µm is better, and 2µm~5µm is better. As long as the thickness of the polarizer is within the above range, it can greatly contribute to the thinning of the polarizing plate with the retardation layer. Furthermore, the effect of the present invention is very remarkable in a polarizing plate with a thin retardation layer using the polarizing element.

The boric acid content of the polarizer is preferably more than 10% by weight, preferably 13% to 25% by weight. As long as the boric acid content of the polarizer is within the above range, the synergistic effect with the iodine content described below can maintain the ease of adjusting the curling during lamination and effectively suppress the curling during heating, and at the same time improve the appearance during heating. Durability. The boric acid content can be calculated, for example, by the neutralization method using the following formula as the amount of boric acid contained per unit weight of the polarizer. [Mathematical formula 1]

The iodine content of the polarizing element is preferably more than 2% by weight, preferably 2% to 10% by weight. As long as the iodine content of the polarizer is within the above range, the synergistic effect with the above-mentioned boric acid content can maintain the ease of adjusting the curling during lamination and effectively suppress the curling during heating, while improving the appearance during heating. Durability. The "iodine content" in this specification means the amount of all iodine contained in the polarizer (PVA-based resin film). More specifically, iodine exists in the polarizer in the form of iodine ions (I ^- ), iodine molecules (I ₂ ), polyiodide ions (I ₃ ^- , I ₅ ^- ), etc., and the iodine content in this specification means Amounts containing all such forms of iodine. The iodine content can be calculated using, for example, the calibration curve method of X-ray fluorescence analysis. In addition, polyiodide ions exist in a state of forming a PVA-iodine complex in the polarizer. By forming the complex, absorption dichroism can be exhibited in the wavelength range of visible light. Specifically, the complex of PVA and triiodide ions (PVA·I ₃ ^- ) has an absorption peak near 470 nm, while the complex of PVA and pentaiodide ions (PVA·I ₅ ^- ) has an absorption peak near 600 nm. Absorption peak. As a result, polyiodide ions can absorb light in a wide range of visible light depending on their morphology. On the other hand, iodide ions (I ⁻ ) have an absorption peak near 230 nm, which is essentially irrelevant to the absorption of visible light. Therefore, the polyiodide ions existing in the state of complex with PVA are mainly related to the absorption performance of the polarizer.

The polarizer should show absorption dichroism at any wavelength from 380nm to 780nm. The single transmittance Ts of the polarizer should be 40% to 48%, more preferably 41% to 46%. The polarization degree P of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and even more preferably 99.9% or more. The above-mentioned monomer transmittance represents the Y value obtained by measuring it using an ultraviolet-visible light spectrophotometer and correcting the visual sensitivity. The above-mentioned degree of polarization is represented by the following formula based on the parallel transmittance Tp and the orthogonal transmittance Tc measured using an ultraviolet-visible spectrophotometer and corrected for visual sensitivity. Polarization degree (%)={(Tp-Tc)/(Tp+Tc)} ^1/2 ×100

Polarizers can typically be produced using a laminate of two or more layers. Specific examples of polarizers obtained using a laminate include polarizers obtained using a laminate of a resin base material and a PVA-based resin layer coated on the resin base material. A polarizer obtained by using a laminate of a resin base material and a PVA-based resin layer coated on the resin base material can be produced, for example, by applying a PVA-based resin solution to the resin base material and drying it. and forming a PVA-based resin layer on the resin base material to obtain a laminated body of the resin base material and the PVA-based resin layer; and extending and dyeing the laminated body to make the PVA-based resin layer into a polarizer. The stretching typically includes immersing the laminate in a boric acid aqueous solution and stretching. And if necessary, stretching may further include stretching the laminate in the air at a high temperature (for example, 95° C. or higher) before stretching in a boric acid aqueous solution. The obtained laminated body of the resin base material/polarizing element can be used directly (that is, the resin base material can be used as a protective layer of the polarizing element), or the resin base material can be peeled off from the laminated body of the resin base material/polarizing element and placed on the peeling surface. Laminate any appropriate protective layer for later use depending on the purpose. Details of the manufacturing method of the 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 quoted in this specification as a reference.

The manufacturing method of a polarizer typically includes the following steps: forming 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; and, for the above The laminated body is sequentially subjected to air-assisted stretching treatment, dyeing treatment, water stretching treatment and drying shrinkage treatment. The drying and shrinking treatment is to transport the above-mentioned laminated body in the longitudinal direction while heating it, thereby shrinking it by 2% in the width direction. above. This makes it possible to provide a polarizer that is very thin and has excellent optical properties with suppressed variation in optical properties. That is, by introducing auxiliary stretching, the crystallinity of PVA can be improved even when PVA is coated on a thermoplastic resin, and high optical properties can be achieved. At the same time, improving the orientation of PVA in advance can prevent problems such as the decrease in orientation or dissolution of PVA when immersed in water in the subsequent dyeing step or stretching step, thereby achieving high optical properties. In addition, when the PVA-based resin layer is immersed in a liquid, compared with the case where the PVA-based resin layer does not contain halides, the orientation disorder and decrease in orientation of polyvinyl alcohol molecules can be suppressed. Thereby, the optical characteristics of the polarizing element obtained by immersing the laminate in a liquid, such as dyeing treatment and water stretching treatment, can be improved. In addition, the optical properties can be improved by shrinking the laminate in the width direction through drying and shrinkage treatment.

B-2.Protective layer The protective layer 12 is formed of any appropriate film that can be used as a protective layer of the polarizer. Specific examples of the material that is the main component of the film include cellulose-based resins such as triacetylcellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, and polyamide-based resins. Imine-based, polyether-based, polystyrene-based, polystyrene-based, polynorbornene-based, polyolefin-based, (meth)acrylic-based and acetate-based transparent resins, etc. Furthermore, thermosetting resins such as (meth)acrylic-based, urethane-based, (meth)acrylic-urethane-based, epoxy-based, and polysiloxane-based resins, or ultraviolet curable resins can also be cited. Other examples include glassy polymers such as siloxane polymers. Furthermore, the polymer film described in Japanese Patent Application Laid-Open No. 2001-343529 (WO01/37007) can also be used. As the material of the film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted acyl imine 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, for example Examples include resin compositions having an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile-styrene copolymer. The polymer film may be, for example, an extruded product of the above-mentioned resin composition.

The polarizing plate with the retardation layer is typically arranged on the viewing side of the image display device as will be described later, and the protective layer 12 is typically arranged on the viewing side. Therefore, the protective layer 12 may also be subjected to surface treatments such as hard coating treatment, anti-reflection treatment, anti-adhesion treatment, and anti-glare treatment as needed. And/or, if necessary, the protective layer 12 may also be subjected to processing to improve the visibility when viewed through polarized sunglasses (typically, imparting (elliptical) polarization function and imparting ultra-high phase difference). By performing the above processing, excellent visibility can be achieved even when the display screen is viewed through polarized lenses such as polarized sunglasses. Therefore, the polarizing plate with the retardation layer can also be suitably used in an image display device that can be used outdoors.

The thickness of the protective layer should be 10µm~50µm, more preferably 10µm~30µm. In addition, when surface treatment is provided, the thickness of the outer protective layer includes the thickness of the surface treatment layer.

C. 1st phase difference layer The first retardation layer 20 is a liquid crystal alignment solidified layer as described above. By using a liquid crystal compound, the difference between nx and ny of the resulting retardation layer can be much larger than that of non-liquid crystal materials, so the thickness of the retardation layer required to obtain the desired in-plane phase difference can be greatly reduced. As a result, the polarizing plate with the retardation layer can be further thinned. The so-called "liquid crystal orientation solidified layer" in this specification refers to a layer in which the liquid crystal compound is oriented in a predetermined direction within the layer, and its orientation state is fixed. In addition, the concept of "directionally hardened layer" includes a directionally hardened layer obtained by hardening a liquid crystal monomer as described later. In this embodiment, it means that the rod-shaped liquid crystal compounds are aligned in a state aligned along the slow axis direction of the first retardation layer (epiplane alignment).

Examples of the liquid crystal compound include a liquid crystal compound whose liquid crystal phase is a nematic phase (nematic liquid crystal). As such a liquid crystal compound, for example, a liquid crystal polymer or a liquid crystal monomer can be used. The liquid crystallinity expression mechanism of the liquid crystal compound may be either lyotropic or thermotropic. The liquid crystal polymer and the liquid crystal monomer can each 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 crosslinking (that is, hardening) the liquid crystal monomer. After the liquid crystal monomers are oriented, for example, the liquid crystal monomers are polymerized or cross-linked with each other, thereby fixing the above-mentioned orientation state. Here, the polymer is formed by polymerization, and the three-dimensional network structure is formed by cross-linking, but these are non-liquid crystalline. Therefore, the formed first retardation layer does not undergo transformation into a liquid crystal phase, a glass phase, or a crystal phase due to temperature changes, which is unique to liquid crystalline compounds. As a result, the first retardation layer becomes a retardation layer that is not affected by temperature changes and has extremely excellent stability.

The temperature range in which liquid crystal monomers exhibit liquid crystallinity varies depending on their 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.

Any appropriate liquid crystal monomer can be used as the above-mentioned liquid crystal monomer. For example, polymerizable mesogen compounds described in Japanese Patent List 2002-533742 (WO00/37585), EP358208 (US5211877), EP66137 (US4388453), WO93/22397, EP0261712, DE19504224, DE4408171, and GB2280445 can be used. . Specific examples of the polymerizable mesogen compound include LC242, a trade name of BASF, E7, a trade name of Merck, and LC-Sillicon-CC3767, a trade name of Wacker-Chem. The liquid crystal monomer is preferably a nematic liquid crystal monomer, for example.

The liquid crystal orientation solidified layer can be formed by performing orientation treatment on the surface of a predetermined base material, and coating a coating liquid containing a liquid crystal compound on the surface so that the liquid crystal compound is oriented in a direction corresponding to the orientation treatment and fixed. the orientation status. In one embodiment, the base material is any appropriate resin film, and the liquid crystal alignment solidified layer formed on the base material can be transferred to the surface of an adjacent layer (eg, polarizer, iodine transmission inhibition layer).

The above orientation processing may adopt any appropriate orientation processing. Specific examples include mechanical orientation treatment, physical orientation treatment, and chemical orientation treatment. Specific examples of mechanical orientation treatment include friction treatment and stretching treatment. Specific examples of physical orientation processing include magnetic field orientation processing and electric field orientation processing. Specific examples of chemical orientation treatment include oblique evaporation and photo-orientation treatment. The processing conditions for various targeted treatments can be any appropriate conditions depending on the purpose.

The orientation of the liquid crystal compound can be carried out by treating the liquid crystal compound at a temperature that can exhibit a liquid crystal phase according to the type of the liquid crystal compound. By performing the temperature treatment, the liquid crystal compound will change into a liquid crystal state, and the liquid crystal compound will be oriented according to the direction of the orientation treatment on the surface of the substrate.

In one embodiment, the alignment state is fixed by cooling the liquid crystal compound that has been aligned in the above manner. When the liquid crystal compound is a polymerizable monomer or a cross-linking monomer, the alignment state is fixed by subjecting the liquid crystal compound that has been aligned in the above manner to a polymerization treatment or a cross-linking treatment.

Specific examples of the liquid crystal compound and details of the formation method of the orientationally solidified layer are described in Japanese Patent Application Laid-Open No. 2006-163343. The records in this publication are cited in this specification as a reference.

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

The first phase difference layer has a circular polarization function or an elliptical polarization function as described above. The refractive index characteristics of the first phase difference layer represent the relationship of nx>ny=nz. The first retardation layer is typically provided to impart anti-reflective properties to the polarizing plate. When the first retardation layer is a single layer, it can function as a λ/4 plate. At this time, the in-plane phase difference Re (550) of the first retardation layer is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, and more preferably 130 nm to 160 nm. In addition, "ny=nz" here includes not only the case where ny and nz are exactly the same, but also the case where they are substantially the same. Therefore, the situation may be ny>nz or ny<nz as long as the effect of the present invention is not impaired.

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

The first phase difference layer can exhibit inverse wavelength dispersion characteristics in which the phase difference value becomes larger with the wavelength of the measurement light, can exhibit normal wavelength dispersion characteristics in which the phase difference value becomes smaller with the wavelength of the measurement light, and can also exhibit that the phase difference value hardly varies with the wavelength of the measurement light. Flat wavelength dispersion characteristics that measure changes in wavelength of light. In one embodiment, the first retardation layer exhibits reverse dispersion wavelength characteristics. At this time, Re(450)/Re(550) of the phase difference layer is preferably 0.8 or more and less than 1, and more preferably 0.8 or more and 0.95 or less. As long as it has the above configuration, very excellent anti-reflection properties can be achieved.

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

In another embodiment, as shown in FIG. 3 , the first retardation layer 20 has a laminated structure of a first liquid crystal alignment solidified layer 21 and a second liquid crystal alignment solidified layer 22 . At this time, either one of the first liquid crystal orientation solidified layer 21 and the second liquid crystal orientation solidified layer 22 can function as a λ/4 plate, and the other can function as a λ/2 plate. Therefore, the thicknesses of the first liquid crystal alignment solidified layer 21 and the second liquid crystal alignment solidified layer 22 can be adjusted to obtain a desired in-plane phase difference of the λ/4 plate or the λ/2 plate. For example, when the first liquid crystal alignment solidified layer 21 functions as a λ/2 plate and the second liquid crystal alignment solidified layer 22 functions as a λ/4 plate, the thickness of the first liquid crystal alignment solidified layer 21 is, for example, 2.0 μm to 3.0 μm. The thickness of the second liquid crystal alignment solidified layer 22 is, for example, 1.0µm~2.0µm. At this time, the in-plane phase difference Re(550) of the first liquid crystal alignment solidified layer is preferably 200nm~300nm, more preferably 230nm~290nm, and more preferably 250nm~280nm. The in-plane phase difference Re (550) of the second liquid crystal alignment solidified layer is as described above for a single layer. The angle formed by the slow axis of the first liquid crystal alignment solidified layer and the absorption axis of the polarizer is preferably 10° to 20°, more preferably 12° to 18°, and more preferably about 15°. The angle formed by the slow axis of the second liquid crystal alignment solidified layer and the absorption axis of the polarizer is preferably 70° to 80°, more preferably 72° to 78°, and more preferably about 75°. With the above configuration, characteristics close to ideal reverse wavelength dispersion characteristics can be obtained, and as a result, very excellent anti-reflection characteristics can be achieved. The liquid crystal compound constituting the first liquid crystal alignment solidified layer and the second liquid crystal alignment solidified layer, the formation method, optical properties, etc. of the first liquid crystal alignment solidified layer and the second liquid crystal alignment solidified layer are as described above for the single layer.

D. Iodine Transmission Suppression Layer The iodine transmission suppression layer has an iodine absorption index of 0.015 or less as described above. The iodine absorption index is preferably 0.012 or less, more preferably 0.009 or less, more preferably 0.007 or less, especially 0.005 or less. The smaller the iodine absorption index, the better, and ideally is zero, and the lower limit thereof may be, for example, 0.001. The iodine absorption index is an indicator of the iodine penetration inhibition ability of the iodine penetration inhibition layer. The smaller the index, the more difficult it is for iodine to be absorbed by the iodine penetration inhibition layer (that is, iodine is easily blocked by the iodine penetration inhibition layer). Therefore, as long as the iodine absorption index is within the above range, when a polarizing plate with a retardation layer is applied to an image display device, the movement of iodine in the polarizer to the image display device (essentially an image display unit) can be significantly inhibited. . As a result, when the polarizing plate with the retardation layer is applied to an image display device, the decrease in reliability caused by iodine in a high-temperature and high-humidity environment can be suppressed, thereby suppressing an increase in reflectivity. Furthermore, the iodine permeation inhibiting layer is as described above, and the potassium absorption index is preferably 0.015 or less. The potassium absorption index is preferably below 0.013, more preferably below 0.011, especially below 0.009. The smaller the potassium absorption index, the better, and ideally is zero, and the lower limit thereof may be, for example, 0.002. The potassium absorption index is an indicator of the potassium penetration inhibition ability of the iodine penetration inhibition layer. The smaller the index, the less easily potassium is absorbed by the iodine penetration inhibition layer. As a result, the iodine in the form of potassium iodide and the iodine in the form of polyiodide (I ₃ ^- K ⁺ ) are more It is not easily absorbed by the iodine penetration inhibition layer. Therefore, as long as the potassium absorption index is within the above range, not only iodine monomer but also in the form of potassium iodide and potassium polyiodide can inhibit the movement of iodine. The iodine absorption index can be defined as the iodine intensity (kcps) obtained by X-ray fluorescence analysis of iodine passing through the suppression layer, and the potassium absorption index can be defined as the potassium intensity (kcps) obtained by X-ray fluorescence analysis of iodine passing through the suppression layer.

The iodine permeation inhibiting layer represents a cured product or a thermally cured product of a coating film coated with an organic solvent solution of resin. The cured or thermally cured product of a coating film of a resin solution in an organic solvent. As long as it has the above structure, the thickness can be made very thin (for example, 10 μm or less). The thickness of the iodine penetration inhibition layer is preferably 0.05µm~10µm, more preferably 0.08µm~5µm, more preferably 0.1µm~1µm, especially 0.2µm~0.7µm. Furthermore, as long as the structure is as described above, the iodine transmission inhibiting layer can be formed directly (that is, without passing through the adhesive layer or adhesive layer) on the adjacent layer (for example, the polarizer, the retardation layer). According to the embodiment of the present invention, as mentioned above, the polarizer, the retardation layer and the iodine transmission suppression layer are very thin, and the adhesive layer or adhesive layer for laminating the iodine transmission suppression layer can be omitted, so the polarized light with the retardation layer can be omitted. The total thickness of the board is extremely thin. In addition, since the hygroscopicity and moisture permeability of this iodine permeation inhibiting layer are smaller than those of cured products of water-based coating films such as aqueous solutions or water dispersions, it has the advantage of excellent humidification durability. As a result, a polarizing plate with a retardation layer having excellent durability and maintaining optical characteristics even in a high-temperature and high-humidity environment can be realized. In addition, such an iodine transmission inhibiting layer can suppress the adverse effects of ultraviolet irradiation on a polarizing plate (polarizer) compared to, for example, a cured product of an ultraviolet curable resin. The iodine permeation inhibiting layer is preferably a cured product of a coating film of a resin organic solvent solution. Compared with cured products, the cured product shrinks less during film formation and does not contain residual monomers. Therefore, it can suppress the deterioration of the film itself and prevent the negative effects of residual monomers on the polarizing plate (polarizer).

Furthermore, the glass transition temperature (Tg) of the resin constituting the iodine transmission suppressing layer is, for example, 85° C. or higher, and the weight average molecular weight Mw is, for example, 25,000 or higher. As long as the Tg and Mw of the resin are within the above ranges, the synergistic effect of constituting the iodine transmission inhibiting layer with the cured product or thermosetting product of the coating film using the organic solvent solution of the resin can be achieved even if it is extremely Thin, it can still significantly inhibit the iodine in the polarizer from moving to the image display unit. As a result, when the polarizing plate with the retardation layer is applied to an image display device, the decrease in reliability caused by iodine in a high-temperature and high-humidity environment can be suppressed, thereby suppressing an increase in reflectivity. And it can significantly inhibit corrosion of metal components. The Tg of the resin is preferably 90°C or higher, more preferably 100°C or higher, more preferably 110°C or higher, especially 120°C or higher. The upper limit of Tg may be, for example, 200°C. Furthermore, the Mw of the resin is preferably 30,000 or more, more preferably 35,000 or more, and more preferably 40,000 or more. The upper limit of Mw may be, for example, 150,000.

As the resin constituting the iodine permeation inhibiting layer, any appropriate thermoplastic resin or thermosetting resin can be used as long as it can form a cured product or a thermosetting product of a coating film of an organic solvent solution and has the above-mentioned Tg and Mw. Thermoplastic resin is preferred. Examples of the thermoplastic resin include acrylic resin and epoxy resin. Acrylic resin and epoxy resin can also be used in combination. Representative examples of acrylic resins and epoxy resins that can be used to inhibit iodine permeation inhibition layers are described below.

Acrylic resins typically contain repeating units derived from (meth)acrylic acid ester monomers having a linear or branched structure as a main component. In this specification, (meth)acrylic acid means acrylic acid and/or methacrylic acid. Acrylic resins may contain repeating units derived from any suitable comonomer suited to the purpose. Examples of the copolymer (copolymer) include carboxyl group-containing monomers, hydroxyl group-containing monomers, amide group-containing monomers, aromatic ring-containing (meth)acrylate, and heterocyclic ring-containing vinyl-based monomers. By appropriately setting the type, quantity, combination, copolymerization ratio, etc. of monomer units, an acrylic resin having the above-mentioned predetermined Mw can be obtained.

<Boron-containing acrylic resin> In one embodiment, the acrylic resin contains a copolymer obtained by polymerizing a monomer mixture (hereinafter sometimes referred to as boron-containing acrylic resin), and the monomer mixture contains More than 50 parts by weight of (meth)acrylic monomer and more than 0 parts by weight and less than 50 parts by weight of the monomer represented by formula (1) (hereinafter sometimes referred to as comonomer): [Chemical Formula 2] (In the formula, At least one reactive group in the group consisting of an ether group, an epoxy group, an oxetanyl group, a hydroxyl group, an amine group, an aldehyde group and a carboxyl group. R ¹ and R ² each independently represent a hydrogen atom and may be substituted. The base is an aliphatic hydrocarbon group, an aryl group that may have a substituent, or a heterocyclic group that may have a substituent, and R ¹ and R ² may be connected to each other to form a ring).

Boron-containing acrylic resins typically have repeating units represented by the following formula. By polymerizing a monomer mixture including a comonomer represented by formula (1) and a (meth)acrylic monomer, the boron-containing acrylic resin has a boron-containing substituent in the side chain (for example, in the following formula k repeating unit). Thereby, when the iodine transmission suppressing layer is arranged adjacent to the polarizer, the adhesion with the polarizer can be improved. The boron-containing substituent may be connected to the boron-containing acrylic resin (that is, in the form of a block) or may be contained randomly. [Chemical formula 3] (In the formula, R ⁶ represents any functional group, j and k represent integers above 1).

＜(meth)acrylic monomer＞ As the (meth)acrylic monomer, any appropriate (meth)acrylic monomer can be used. Examples thereof include (meth)acrylate monomers having a linear or branched structure and (meth)acrylate monomers having a cyclic structure.

Examples of (meth)acrylate monomers having a linear or branched structure include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and (meth)acrylic acid. Isopropyl ester, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tertiary butyl (meth)acrylate, methyl 2-ethylhexyl (meth)acrylate, (meth)acrylate 2-hydroxyethyl acrylate, etc. Preferably, methyl (meth)acrylate can be used. (Meth)acrylate-based monomers may be used alone or in combination of two or more types.

Examples of the (meth)acrylate monomer having a cyclic structure include cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isocamphenyl (meth)acrylate, and 1-(meth)acrylate. Adamantyl ester, dicyclopentenyl (meth)acrylate, dicyclopentyloxyethyl (meth)acrylate, dicyclopentyl (meth)acrylate, biphenyl (meth)acrylate, ortho- Phenoxyethyl (meth)acrylate, o-biphenoxyethyl (meth)acrylate, m-biphenoxyethyl acrylate, p-biphenoxyethyl (meth)acrylate, o-biphenoxyethyl (meth)acrylate Phenoxy-2-hydroxypropyl (meth)acrylate, p-biphenoxy-2-hydroxypropyl (meth)acrylate, m-biphenoxy-2-hydroxypropyl (meth)acrylate , N-(meth)acryloxyethyl-o-biphenyl=carbamate, N-(meth)acryloxyethyl-p-biphenyl=carbamate, N-(methyl) Acryloxyethyl-m-biphenyl = urethane, o-phenylphenol glycidyl ether acrylate and other biphenyl-containing monomers, triphenyl (meth)acrylate, o-triphenoxyethyl (meth)acrylate, etc. Preferably, 1-adamantyl (meth)acrylate and dicyclopentyl (meth)acrylate can be used. By using these monomers, polymers with high glass transition temperatures can be obtained. These monomers may be used only 1 type or in combination of 2 or more types.

Furthermore, a silsesquioxane compound having a (meth)acrylyl group may be used instead of the (meth)acrylate monomer. By using a silsesquioxane compound, an acrylic polymer with a high glass transition temperature can be obtained. It is known that silsesquioxane compounds have various skeleton structures such as cage structures, ladder structures, random structures, and the like. The silsesquioxane compound may have only one type of these structures, or may have two or more types. As for the silsesquioxane compound, only one type may be used or two or more types may be used in combination.

As the silsesquioxane compound containing (meth)acrylyl group, for example, MAC grade and AC grade of Toa Gosei Co., Ltd.'s SQ series can be used. MAC grade is a silsesquioxane compound containing methacrylyl groups. Specific examples include MAC-SQ TM-100, MAC-SQ SI-20, MAC-SQ HDM, etc. AC grade is a silsesquioxane compound containing an acryl group. Specific examples include AC-SQ TA-100, AC-SQ SI-20, etc.

The (meth)acrylic monomer can be used in an amount of more than 50 parts by weight relative to 100 parts by weight of the monomer mixture.

＜Comonomer＞ As the copolymerizable monomer, a monomer represented by the above formula (1) can be used. By using the comonomer, boron-containing substituents can be introduced into the side chains of the resulting polymer. As the comonomer, only one type may be used or two or more types may be used in combination.

Examples of the aliphatic hydrocarbon group of the above formula (1) include linear or branched alkyl groups having 1 to 20 carbon atoms which may have substituents, cyclic alkyl groups having 3 to 20 carbon atoms or alkenes having 2 to 20 carbon atoms which may have substituents. base. Examples of the aryl group include a phenyl group having 6 to 20 carbon atoms which may have a substituent, a naphthyl group having 10 to 20 carbon atoms which may have a substituent, and the like. Examples of the heterocyclic group include a 5-membered cyclic group or a 6-membered cyclic group containing at least 1 heteroatom which may have a substituent. In addition, R ¹ and R ² may be linked 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, more preferably a hydrogen atom.

The reactive group included in the functional group represented by At least one kind from the group consisting of heterocyclobutanyl group, hydroxyl group, amine group, aldehyde group and carboxyl group. Preferably, the reactive group is a (meth)acrylyl group and/or a (meth)acrylamide group. By having such reactive groups, when the iodine transmission inhibiting layer is arranged adjacent to the polarizer, the adhesion to the polarizer can be further improved.

In one embodiment, the functional group represented by X is preferably a functional group represented by Z-Y-. Here, Z represents a functional group containing a reactive group, and the reactive group is selected from the group consisting of vinyl, (meth)acrylyl, styryl, (meth)acrylamide, vinyl ether At least one reactive group in the group consisting of a group, an epoxy group, an oxetanyl group, a hydroxyl group, an amine group, an aldehyde group and a carboxyl group, and Y represents a phenylene group or an alkylene group.

Specifically, the following compounds can be used as comonomers. [Chemical formula 4] [Chemical formula 5]

The comonomer may be used in a content of greater than 0 parts by weight and less than 50 parts by weight relative to 100 parts by weight of the monomer mixture. It is preferably more than 0.01 parts by weight and less than 50 parts by weight, more preferably 0.05 to 20 parts by weight, more preferably 0.1 to 10 parts by weight, especially 0.5 to 5 parts by weight.

＜Acrylic resin containing lactone ring, etc.＞

In another embodiment, the acrylic resin has repeating units including a ring structure selected from the group consisting of lactone ring units, glutaric anhydride units, glutadiryl imine units, maleic anhydride units and maleic anhydride units. Amine (N-substituted maleimine) unit. Only one type of repeating unit including a ring structure may be contained in the repeating unit of the acrylic resin, or two or more types may be contained therein.

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

[Chemical formula 6] In the general formula (2), R ² , R ³ and R ⁴ each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms. In addition, organic residues may also contain oxygen atoms. The acrylic resin may contain only a single lactone ring unit, or may contain a plurality of lactone ring units in which R ² , R ³ and R ⁴ in the general formula (2) are different from each other. Acrylic resins having a lactone ring unit are described in, for example, Japanese Patent Application Laid-Open No. 2008-181078, and the description of this publication is used as a reference in this specification.

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

[Chemical Formula 7]

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 represents an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or a cycloalkyl group having 6 to 10 carbon atoms. Aryl. In the general formula (3), it is desirable that R ¹¹ and R ¹² are independently hydrogen or methyl, and R ¹³ is hydrogen, methyl, butyl or cyclohexyl. More preferably, R ¹¹ is methyl, R ¹² is hydrogen, and R ¹³ is methyl. The acrylic resin may contain only a single glutarimide unit, or may contain a plurality of glutarimide units in which R ¹¹ , R ¹² and R ¹³ in the general formula (3) are different from each other. Acrylic resins having a glutadirylimine unit are described in, for example, Japanese Patent Laid-Open No. 2006-309033, Japanese Patent Laid-Open No. 2006-317560, Japanese Patent Laid-Open No. 2006-328334, and Japanese Patent Laid-Open No. 2006 -337491, Japanese Patent Application Publication No. 2006-337492, Japanese Patent Application Publication No. 2006-337493, and Japanese Patent Application Publication No. 2006-337569, and the descriptions of these publications are cited in this specification. In addition, for the glutaric anhydride unit, except that the nitrogen atom substituted by R ¹³ of the above general formula (3) is changed to an oxygen atom, the above description about the glutaric imine unit is applicable.

The structure of the maleic anhydride unit and the maleimide (N-substituted maleimide) unit can be identified by their names, so detailed descriptions are omitted.

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

＜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, when the iodine transmission inhibiting layer is arranged adjacent to the polarizer, the adhesion to the polarizer can be improved. In addition, when the adhesive layer is arranged adjacent to the iodine transmission inhibiting layer, the anchoring force of the adhesive layer can be improved. Examples of epoxy resins having aromatic rings include bisphenol-type epoxy resins such as bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, and bisphenol S-type epoxy resin; phenol novolac epoxy resin, and cresol Phenolic epoxy resins such as phenolic epoxy resin, hydroxybenzaldehyde phenol phenolic epoxy resin and other phenolic epoxy resins; glycidyl ether of tetrahydroxyphenylmethane, epoxypropyl ether of tetrahydroxydiphenylketone, epoxidized polyvinyl phenol, etc. Multifunctional epoxy resin, naphthol-type epoxy resin, naphthalene-type epoxy resin, biphenyl-type epoxy resin, etc. Preferably, bisphenol A-type epoxy resin, biphenyl-type epoxy resin, and bisphenol F-type epoxy resin can be used. As for the epoxy resin, only one type may be used or two or more types may be used in combination.

The iodine permeation inhibiting layer can be formed by coating an organic solvent solution of the above-mentioned resin to form a coating film, and solidifying or thermally hardening the coating film. As the organic solvent, any appropriate organic solvent that can dissolve or uniformly disperse 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 to 20 parts by weight relative to 100 parts by weight of the solvent. As long as the resin concentration is the above, a uniform coating film can be formed.

The solution can be coated on any appropriate substrate, or on adjacent layers (such as polarizers, retardation layers). When the solution is applied to the base material, the cured product of the coating film formed on the base material (iodine transmission inhibiting layer) is transferred to the adjacent layer. When the solution is applied to the adjacent layer, the coating film is dried (cured) to form a protective layer directly on the adjacent layer. Preferably, the solution is coated on the adjacent layer, and the protective layer is directly formed on the adjacent layer. With the above configuration, the adhesive layer or adhesive layer required for transfer can be omitted, so the polarizing plate with the retardation layer can be made thinner. The solution may be applied by any appropriate method. Specific examples include roll coating, spin coating, wire bar coating, dip coating, die coating, curtain coating, spray coating, and blade coating (notched wheel coating, etc.).

By solidifying or thermally hardening the coating film of the solution, the iodine transmission inhibiting layer can be formed. The heating temperature for curing or thermal hardening should be below 100°C, preferably 50°C to 70°C. As long as the heating temperature is within the above range, adverse effects on the polarizer can be prevented. The heating time can be changed according to the heating temperature. The heating time can be, for example, 1 minute to 10 minutes.

The iodine permeation inhibition layer (essentially an organic solvent solution of the above-mentioned resin) may also contain any appropriate additives according to the purpose. Specific examples of additives include ultraviolet absorbers; leveling agents; antioxidants such as hindered phenol series, phosphorus series, and sulfur series; stabilizers such as light stabilizers, weathering stabilizers, and heat stabilizers; reinforcing materials such as glass fiber and carbon fiber; Near-infrared absorbers; flame retardants such as ginseng (propyl dibromide) phosphate, triallyl phosphate, and antimony oxide; antistatic agents such as anionic, cationic, and nonionic surfactants; inorganic pigments, Colorants such as organic pigments and dyes; organic fillers or inorganic fillers; resin modifiers; organic fillers or inorganic fillers; plasticizers; slip agents; antistatic agents; flame retardants, etc. The type, quantity, combination, addition amount, etc. of additives can be appropriately set according to the purpose.

E. 2nd phase difference layer As mentioned above, the second retardation layer may be a so-called positive C-plate whose refractive index characteristics exhibit the relationship nz>nx=ny. By using the positive C plate as the second retardation layer, oblique reflection can be effectively prevented, and the anti-reflection function can be widened to a wider viewing angle. At this time, the retardation Rth (550) in the thickness direction of the second retardation layer is preferably -50nm~-300nm, more preferably -70nm~-250nm, more preferably -90nm~-200nm, especially -100nm~ -180nm. Here, "nx=ny" includes not only the case where nx and ny are strictly equal, but also the case where nx and ny are substantially equal. That is, the in-plane phase difference Re(550) of the second retardation layer may be less than 10 nm.

The second retardation layer having the refractive index characteristic of nz>nx=ny can be formed of any appropriate material. The second retardation layer is preferably composed of a thin film containing a liquid crystal material fixed in a homeotropic orientation. The liquid crystal material (liquid crystal compound) capable of vertical alignment can be a liquid crystal monomer or a liquid crystal polymer. Specific examples of the method of forming the liquid crystal compound and the retardation layer include the liquid crystal compound and the method of forming the retardation layer described in paragraphs [0020] to [0028] of Japanese Patent Application Laid-Open No. 2002-333642. At this time, the thickness of the second retardation layer is preferably 0.5µm~10µm, more preferably 0.5µm~8µm, and more preferably 0.5µm~5µm.

F. Conductive layer or isotropic substrate with conductive layer The conductive layer can be formed by forming a metal oxide film on any appropriate substrate using any appropriate film forming method (such as vacuum evaporation, sputtering, CVD, ion plating, spraying, etc.). Examples of metal oxides include indium oxide, tin oxide, zinc oxide, indium-tin composite oxide, tin-antimony composite oxide, zinc-aluminum composite oxide, and indium-zinc composite oxide. Among them, indium tin composite oxide (ITO) is preferred.

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 can be made by transferring the above-mentioned base material to the first retardation layer (or the iodine transmission inhibition layer or the second retardation layer when there is a second retardation layer), and the conductive layer alone serves as the attached retardation layer. The constituent layers of the polarizing plate can also be laminated in the form of a laminate of a conductive layer and a base material (a base material with a conductive layer) on the first retardation layer (or the iodine transmission suppression layer or the second retardation layer) is the second phase difference layer). Preferably, the above-mentioned substrate is optically isotropic, so the conductive layer can be used as an isotropic substrate with a conductive layer for a polarizing plate with a retardation layer.

Any appropriate isotropic base material can be used as the optically isotropic base material (isotropic base material). Examples of materials constituting the isotropic base material include materials having a main skeleton of a resin without a conjugated system, such as norbornene resin or olefin resin, and acrylic resin having a lactone ring or glutaryl ring in the main chain. Materials with cyclic structures such as imine rings, etc. If such a material is used, the phase difference caused by the orientation of molecular chains when forming an isotropic base material can be suppressed to a small size. The thickness of the isotropic substrate should be 50µm or less, more preferably 35µm or less. The lower limit of the thickness of the isotropic substrate is, for example, 20µm.

The conductive layer and/or the conductive layer of the isotropic substrate with the conductive layer can be patterned as needed. Conductive portions and insulating portions can be formed through patterning. As a result, electrodes can be formed. The electrodes may function as touch sensing electrodes for sensing contact with the touch panel. The patterning method may employ any suitable method. Specific examples of the patterning method include wet etching and screen printing.

G.Image display device The polarizing plate with a retardation layer described in the above items A to F can be applied to an image display device. Therefore, embodiments of the present invention include an image display device using the polarizing plate with a retardation layer. Representative examples of image display devices include liquid crystal display devices and electroluminescence (EL) display devices (for example, organic EL display devices and inorganic EL display devices). An image display device according to an embodiment of the present invention is provided with the polarizing plate with a retardation layer described in the above items A to F on its viewing side. The polarizing plate with the retardation layer is laminated so that the retardation layer becomes the side of the image display unit (for example, liquid crystal unit, organic EL unit, inorganic EL unit) (the polarizer becomes the viewing side). Although the image display device is very thin, it has good reliability in high temperature and high humidity environments, and the increase in reflectivity is suppressed. Moreover, corrosion of metal components is significantly inhibited. In one embodiment, the image display device has a curved shape (substantially a curved display screen), and/or is bendable or foldable.

Example Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited by these examples. The measurement method of each characteristic is as follows. In addition, unless otherwise noted, "parts" and "%" in the examples and comparative examples are based on weight.

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

(2) Iodine absorption index and potassium absorption index The resin solutions used in the examples and comparative examples were coated on a 38 µm polyethylene terephthalate (PET) film so that the dried thickness became 1 µm and dried to obtain a test sample of the resin layer/PET film. . The obtained test sample was immersed in a 10% potassium iodide aqueous solution (90 parts by weight of pure water, 10 parts by weight of potassium iodide) adjusted to 23°C for 24 hours. After immersion, the test sample is taken out from the aqueous solution, and after wiping the water droplets on the surface, X-ray fluorescence measurement is performed on the surface of the resin layer to obtain the intensity of iodine and potassium (kcps). The strength of the obtained iodine was taken as the iodine absorption index, and the strength of the potassium was taken as the potassium absorption index. In addition, the conditions for X-ray fluorescence analysis are as follows. ・Analysis device: Rigaku Denki Industrial X-ray fluorescence analysis device (XRF), product name "ZSX100e" ・Test sample: circular sample with diameter 10mm ・Counter cathode: rhodium ・Spectral crystallization: lithium fluoride ・Excitation light energy: 40kV-90mA ・Iodine measurement line: I-LA ・Quantitative method: FP method ・2θ angle peak: 103.078deg (iodine), 136.847deg (potassium) ・Measurement time: 40 seconds

(3) Reflectivity increases The polarizing plate with the retardation layer obtained in the Example and the Comparative Example was bonded to the alkali-free glass to prepare a test sample. The test sample was placed on a reflective plate with a reflectance of 80%, and the value measured at 550nm in SCI mode using a spectrophotometer (CM700D manufactured by Konica Minolta Co., Ltd.) was taken as the reflectance (%). as the initial reflectivity. After the test sample is subjected to a reliability test (placed in an environment of 60°C・90%RH for 500 hours, and then placed in an environment of 23°C・55%RH for 24 hours), the reflectance is measured in the same manner as above . The reflectance increase is calculated according to the following equation. Reflectivity increase (%) = initial reflectivity (%) - reflectivity after reliability test (%) and evaluated against the following benchmarks. Good: Reflectivity increase is less than 0.50% Allowable: the reflectivity rises above 0.50% and is less than 1.00% Poor: Reflectivity rises above 1.00%

(4) Metal corrosion (48 hours) Coat the silver nanowire solution (manufactured by MERCK, nanowire size: diameter 115nm, length 20µm~50µm, solid content 0.5% isopropyl alcohol (IPA) solution) with a wire rod so that the wet film thickness becomes 15µm. Apply to one side of a 50µm polyethylene terephthalate (PET) film and dry it in an oven at 100°C for 5 minutes to form a silver nanowire coating. Next, a wet film containing 99 parts of methyl isobutyl ketone (MIBK), 1 part of neopentyl tetraacrylate (PETA), and a photopolymerization initiator (manufactured by BASF Corporation) was used with a wire rod so that the wet film thickness became 10 μm. Product name "IRGACURE 907") 0.03 parts of covering protection liquid (solid content concentration: about 1%) is applied on the surface of the silver nanowire coating film, and dried in an oven at 100°C for 5 minutes. Next, active energy rays were irradiated to harden the protective coating film, thereby producing a metal thin film composed of a PET film/silver nanowire layer/protective coating layer (thickness: 100 nm). Use an adhesive (15µm) to bond the metal film to a glass plate with a thickness of 0.5mm to obtain a laminated body of metal film/adhesive/glass plate. The resistance value of the obtained laminated body was measured with a non-contact resistance measuring instrument (manufactured by Napson Corporation, product name "EC-80") and found to be 50Ω/□.

The polarizing plate with the retardation layer obtained in the Example and the Comparative Example was bonded to the surface of the protective layer of the metal film of the laminate to prepare a test sample. Use a non-contact resistance measuring device to measure the resistance value of the test sample as the initial resistance value. After the test sample is subjected to a reliability test (placed in an environment of 85°C・85%RH for 48 hours, and then placed in an environment of 23°C・55%RH for 2 hours), the resistance value is measured in the same manner as above . Calculate the resistance value increase rate according to the following formula. In addition, when the measured value (resistance value) is greater than the measurement limit of the non-contact resistance measuring device (1000Ω/□), the measured value is assumed to be 1500Ω/□. Resistance value increase rate (%) = {(resistance value after reliability test - initial resistance value)/initial resistance value} × 100 and evaluated against the following benchmarks. Good: The resistance value rise rate is less than 200% Poor: Resistance value increase rate is more than 200%

(5) Metal corrosion (200 hours) The polarizing plate with the retardation layer obtained in the Example and the Comparative Example was bonded to the protective layer-forming surface of the metal film of the laminate obtained in (2) to prepare a test sample. Use a non-contact resistance measuring device to measure the resistance value of the test sample as the initial resistance value. After the test sample is subjected to a reliability test (placed in an environment of 85°C・85%RH for 200 hours, and then placed in an environment of 23°C・55%RH for 2 hours), the resistance value is measured in the same manner as above . Calculate the resistance value increase rate according to the following formula. In addition, when the measured value (resistance value) is greater than the measurement limit of the non-contact resistance measuring device (1000Ω/□), the measured value is assumed to be 1500Ω/□. Resistance value increase rate (%) = {(resistance value after reliability test - initial resistance value)/initial resistance value} × 100 and evaluated against the following benchmarks. Excellent: The resistance value increase rate is less than 200% Good: The resistance value increase rate is above 200% and below 2000% Poor: The resistance value increase rate is more than 2000%

[Example 1] 1. Make polarizers The thermoplastic resin base material is a long amorphous isophthalic acid copolymer polyethylene terephthalate film (thickness: 100µm) with a water absorption rate of 0.75% and a Tg of approximately 75°C. And corona treatment is applied to one side of the resin substrate. A PVA system made by mixing polyvinyl alcohol (degree of polymerization 4200, saponification degree 99.2 mol%) and acetyl-acetyl modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMER Z410") at a ratio of 9:1 13 parts by weight of potassium iodide was added to 100 parts by weight of the resin, and the resultant was dissolved in water to prepare a PVA aqueous solution (coating liquid). The above-mentioned PVA aqueous solution was applied to the corona-treated surface of the resin base material and dried at 60° C. to form a PVA-based resin layer with a thickness of 13 μm, thereby producing a laminate. The obtained laminate was uniaxially stretched in the longitudinal direction (long side direction) at the free end between rollers with different circumferential speeds in an oven at 130° C. to 2.4 times (air-assisted stretching treatment). Next, the laminated body was immersed in an insolubilization bath (a boric acid aqueous solution in which 4 parts by weight of boric acid was mixed with 100 parts by weight of water) having a liquid temperature of 40° C. for 30 seconds (insolubilization treatment). Next, while adjusting the concentration of a dye bath (an iodine aqueous solution obtained by mixing iodine and potassium iodide at a weight ratio of 1:7 with respect to 100 parts by weight of water) with a liquid temperature of 30° C., the dye bath was immersed in it for 60 seconds. The single transmittance (Ts) of the finally obtained polarizing element is 43.0% or more (dyeing treatment). Next, it was immersed in a crosslinking bath (a boric acid aqueous solution obtained by mixing 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with respect to 100 parts by weight of water) with a liquid temperature of 40° C. for 30 seconds (crosslinking treatment) ). Then, the laminated body was immersed in a boric acid aqueous solution with a liquid temperature of 70°C (boric acid concentration 4.0% by weight, potassium iodide concentration 5% by weight), and uniaxially stretched in the longitudinal direction (longitudinal direction) between rollers with different circumferential speeds. Make the total extension ratio reach 5.5 times (extension treatment in water). Thereafter, the laminated body was immersed in a cleaning bath (an aqueous solution in which 4 parts by weight of potassium iodide was mixed with 100 parts by weight of water) having a liquid temperature of 20° C. (washing treatment). Thereafter, it was dried in an oven maintained at 90° C. while keeping the surface temperature in contact with a SUS heated roller at 75° C. for about 2 seconds (drying shrinkage treatment). The laminate was subjected to drying and shrinkage treatment, and the shrinkage rate in the width direction was 5.2%. According to the above method, a polarizer with a thickness of 5 μm is formed on the resin substrate.

2. Make polarizing plates An HC-COP film was bonded to the surface of the polarizer obtained above (the surface opposite to the resin base material) through an ultraviolet curable adhesive as a protective layer. Specifically, the hardening adhesive is applied so that the total thickness becomes 1.0 μm and bonded using a roller. After that, UV light is irradiated from the protective layer side to harden the adhesive. In addition, the HC-COP film is a film with a hard coat (HC) layer (thickness 2µm) formed on a cyclic olefin (COP) film (manufactured by ZEON Corporation of Japan, product name "ZF12", thickness 25µm), and the COP film becomes polarized Fit the side of the piece. Next, the resin base material is peeled off to obtain a polarizing plate having a structure of protective layer (HC layer/COP film)/adhesive layer/polarizer.

3. Prepare the first orientationally solidified layer and the second orientationally solidified layer constituting the retardation layer. 10 g of polymerizable liquid crystal showing the nematic liquid crystal phase (manufactured by BASF: trade name "Paliocolor LC242", represented by the following formula) and 3 g of the photopolymerization initiator of this polymerizable liquid crystal compound (manufactured by BASF: trade name "IRGACURE 907") was dissolved in 40 g of toluene, and a liquid crystal composition (coating liquid) was prepared. [Chemical formula 8] Wipe the surface of polyethylene terephthalate (PET) film (thickness 38 μm) with a wiping cloth and perform orientation treatment. The direction of the orientation treatment is set to be 15° relative to the absorption axis direction of the polarizer when viewed from the viewing side when attached to the polarizing plate. The above-mentioned liquid crystal coating liquid was applied to the orientation-treated surface using a bar coater, and the liquid crystal compound was oriented by heating and drying at 90° C. for 2 minutes. A metal halide lamp is used to irradiate the liquid crystal layer formed in the above manner with light of 1 mJ/cm ² to harden the liquid crystal layer, thereby forming a liquid crystal orientation solidified layer A on the PET film. The thickness of the liquid crystal orientation solidified layer A is 2.5 μm, and the in-plane phase difference Re (550) is 270 nm. Furthermore, the liquid crystal alignment solidified layer A has a refractive index distribution of nx>ny=nz. Change the coating thickness and set the orientation treatment direction to be 75° relative to the absorption axis direction of the polarizer when viewed from the viewing side. In addition, form the liquid crystal orientation solidified layer B on the PET film in the same manner as above. . The thickness of the liquid crystal orientation solidified layer B is 1.5 μm, and the in-plane phase difference Re (550) is 140 nm. Furthermore, the liquid crystal alignment solidified layer B has a refractive index distribution of nx>ny=nz.

4. Form a phase difference layer The liquid crystal orientation solidified layer A and the liquid crystal orientation solidified layer B obtained in the above 3. are sequentially transferred to the surface of the polarizer of the polarizing plate obtained in the above 2.. At this time, the rotation is performed in such a way that the angle formed by the absorption axis of the polarizer and the slow axis of the liquid crystal alignment solidified layer A becomes 15° and the angle formed by the absorption axis of the polarizer and the slow axis of the liquid crystal alignment solidified layer B becomes 75°. Print (fit). In addition, each transfer (bonding) is performed through the ultraviolet curable adhesive (thickness 1.0 μm) used in 2. above. In the above manner, a protective layer (HC layer/COP film)/adhesive layer/polarizer/adhesive layer/retardation layer (first liquid crystal orientation solidified layer/adhesive layer/second liquid crystal orientation solidified layer) is produced. The layered body composed of it.

5. Make a polarizing plate with a phase difference layer 20 parts of acrylic resin (manufactured by Kusumoto Chemicals Co., Ltd., product name "B-811", Tg: 110°C, Mw: 40000) were dissolved in 80 parts of methyl ethyl ketone to obtain a resin solution (20%). The resin solution is applied to the surface of the second liquid crystal alignment solidified layer of the laminate obtained in step 4 above with a wire bar, and the coating film is dried at 60° C. for 5 minutes to form a coating film made of an organic solvent solution of the resin. An iodine transmission inhibiting layer (thickness 0.5µm) formed in the form of a cured product. The iodine absorption index of the iodine penetration inhibition layer is 0.0046, and the potassium absorption index is 0.0087. Next, an adhesive layer (thickness 15 μm) is provided on the surface of the iodine transmission inhibition layer to obtain a protective layer (HC layer/COP film)/adhesive layer/polarizer/adhesive layer/retardation layer (first liquid crystal directional solidification A polarizing plate with a retardation layer composed of layer/adhesive layer/second liquid crystal orientation solidification layer)/iodine transmission inhibiting layer/adhesive layer. 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 used for the evaluation of the above (3) to (5). In addition, the metal corrosiveness was compared with Comparative Example 1 (described later) in which the iodine transmission inhibiting layer was not formed. The results are listed in Table 1 and Table 2.

[Example 2] 97.0 parts of methyl methacrylate (MMA, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "methyl methacrylate monomer"), 3.0 parts of the comonomer represented by the above general formula (1e), and a polymerization initiator ( Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "2,2´-azobis(isobutyronitrile)") 0.2 part was dissolved in 200 parts of toluene. Next, a polymerization reaction was performed for 5.5 hours while heating to 70° C. in a nitrogen atmosphere, and a boron-containing acrylic resin solution (solid content concentration: 33%) was obtained. The obtained boron-containing acrylic polymer had a Tg of 110° C. and a Mw of 80,000. The boron-containing acrylic polymer was used instead of the acrylic resin "B-811" and the thickness of the iodine transmission inhibition layer was set to 0.3 µm. The retardation layer was produced in the same manner as in Example 1. The polarizing plate. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are listed in Table 1 and Table 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 transmission inhibition layer was set to 0.5 μm. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Example 4] The same procedure as in Example 1 was performed except that thermoplastic epoxy resin (manufactured by Mitsubishi Chemical Co., trade name "jER (registered trademark) 1256B40", Tg: 100°C, Mw: 45000) was used instead of the acrylic resin "B-811". In the same way, a polarizing plate with a retardation layer is produced. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Example 5] Use thermoplastic epoxy resin (manufactured by Mitsubishi Chemical Co., trade name "jER (registered trademark) YX7200B35", Tg: 150°C, Mw: 30000) to replace the acrylic resin "B-811", and add iodine permeation inhibition layer to the The thickness was set to 0.3 μm, except that a polarizing plate with a retardation layer was produced in the same manner as in Example 1. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are listed in Table 1 and Table 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 transmission inhibition layer was set to 0.5 μm. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Example 7] In place of the acrylic resin "B", a blend of 15 parts of "B-811" and 85 parts of a thermoplastic epoxy resin (manufactured by Mitsubishi Chemical Co., trade name "jER (registered trademark) YX6954BH30") (in terms of solid content) was used. -811", a polarizing plate with a retardation layer was produced in the same manner as in Example 1. The blend had a Tg of 125°C and a Mw of 38,000. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Example 8] The resin blend used in Example 7 was coated on the polarizer side of the polarizing plate having the structure of protective layer (HC layer/COP film)/adhesive layer/polarizer obtained in Example 1 and 2 and dried. , to form an iodine transmission inhibiting layer (thickness 0.5µm) in the form of a cured product of a coating film of a resin organic solvent solution. Sequentially transfer the liquid crystal orientation solidification layer A and the liquid crystal orientation solidification layer B on the surface of the iodine transmission inhibition layer in the same manner as in Example 1 to obtain a protective layer (HC layer/COP film)/adhesive layer/polarizer/iodine A polarizing plate with a retardation layer composed of a transmission inhibition layer/adhesive layer/retardation layer (first liquid crystal alignment solidified layer/adhesive layer/second liquid crystal alignment solidification layer)/adhesive layer. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are listed in Table 2.

[Example 9] Except using the boron-containing acrylic polymer in Example 2, a protective layer (HC layer/COP film)/adhesive layer/polarizer/iodine transmission inhibiting layer was produced in the same manner as in Example 8. Laminated body. Next, a blend of 15 parts of the boron-containing acrylic polymer in Example 2 and 85 parts of a thermoplastic epoxy resin (manufactured by Mitsubishi Chemical Co., trade name "jER (registered trademark) YX6954BH30") (in terms of solid content) was used. , except that the protective layer (HC layer/COP film)/adhesive layer/polarizer/iodine transmission inhibition layer/adhesive layer/retardation layer (the first liquid crystal orientation solidification layer) was obtained in the same manner as in Example 1. A polarizing plate with a retardation layer composed of layer/adhesive layer/second liquid crystal orientation solidification layer)/iodine transmission inhibiting layer/adhesive layer. 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 listed in Table 2.

[Example 10] The iodine transmission suppression layer disposed between the polarizer and the retardation layer and adjacent to the polarizer was made of 15 parts of the boron-containing acrylic polymer obtained in Example 2 and a thermoplastic epoxy resin (manufactured by Mitsubishi Chemical Co., commercial product). A polarizing plate with a retardation layer was obtained in the same manner as in Example 9 except that 85 parts (in terms of solid content) of the blend (named "jER (registered trademark) YX6954BH30") 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 listed in Table 2.

[Example 11] An iodine transmission inhibition layer is formed between the polarizer and the retardation layer and adjacent to the polarizer. The iodine transmission inhibition layer is formed between the polarizer and the retardation layer and adjacent to the retardation layer. Otherwise, it is the same as in Embodiment 10. Method to obtain a protective layer (HC layer/COP film)/adhesive layer/polarizer/adhesive layer/iodine transmission inhibition layer/retardation layer (first liquid crystal orientation solidification layer/adhesive layer/second liquid crystal orientation solidification A polarizing plate with a retardation layer composed of a layer)/iodine transmission inhibition layer/adhesive layer. 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 listed in Table 2.

[Example 12] In the same manner as in Example 9, an iodine transmission inhibition layer is further formed between the polarizer and the retardation layer and adjacent to the polarizer. In addition, in the same manner as in Example 11, a protective layer (HC layer/ COP film)/adhesive layer/polarizer/iodine transmission suppression layer/adhesive layer/iodine transmission suppression layer/retardation layer (first liquid crystal orientation solidified layer/adhesive layer/second liquid crystal orientation solidification layer)/iodine transmission A polarizing plate with a retardation layer composed of an inhibition layer/adhesive layer. The total thickness of the polarizing plate with the retardation layer obtained 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 listed 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 transmission inhibiting 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 listed in Table 1 and Table 2.

[Comparative example 2] The acrylic resin "B-723" (manufactured by Kusumoto Chemical Co., Ltd., Tg: 54°C, Mw: 200000) was used instead of the acrylic resin "B-811", and a phase-attached phase was produced in the same manner as in Example 1. Differential layer of polarizing plate. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Comparative example 3] A photocurable epoxy resin (manufactured by Mitsubishi Chemical Co., trade name "jER (registered trademark) 828") was used instead of the acrylic resin "B-811", and "CPI100P" manufactured by San-Apro Ltd. was used as the photopolymerization initiator. ), except that a polarizing plate with a retardation layer was produced in the same manner as in Example 1. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Comparative example 4] Except using PVA-based resin (manufactured by Mitsubishi Chemical Co., trade name "GOHSEFIMER Z200", Tg: 80°C, Mw: 8800) instead of the acrylic resin "B-811", the attachment was produced in the same manner as in Example 1. Polarizing plate with phase difference layer. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Reference example 1] 1. Make polarizing plates A polarizing plate having a structure of protective layer (HC layer/COP film)/polarizer 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 resin Batch polymerization using two vertical reactors equipped with stirring blades and a reflux cooler controlled to 100°C device for aggregation. Feed in 29.60 parts by mass (0.046 mol) of bis[9-(2-phenoxycarbonylethyl)fluoren-9-yl]methane, 29.21 parts by mass (0.200 mol) of isosorbide (ISB), and spiroglycerol (SPG) 42.28 parts by mass (0.139 mol), 63.77 parts by mass (0.298 mol) of diphenyl carbonate (DPC) and 1.19×10 ^-2 parts by mass (6.78×10 ^-5 mol) of calcium acetate monohydrate as a catalyst. After the reactor was replaced with nitrogen under reduced pressure, it was heated with a heating medium, and stirring was started when the internal temperature reached 100°C. The internal temperature was brought to 220°C 40 minutes after the temperature rise started, and the pressure was reduced while maintaining the temperature to 13.3 kPa 90 minutes after reaching 220°C. The phenol vapor generated by the polymerization reaction is introduced into a reflux cooler at 100°C, so that a small amount of monomer components contained in the phenol vapor is returned to the reactor, and the uncondensed phenol vapor is introduced into a condenser at 45°C for recovery. After introducing nitrogen into the first reactor and temporarily returning it to atmospheric pressure, the oligomerized reaction liquid in the first reactor is moved to the second reactor. Next, the temperature increase and pressure reduction in the second reactor were started, and the internal temperature was adjusted to 240° C. and the pressure to 0.2 kPa over 50 minutes. Thereafter, polymerization is performed until a predetermined stirring power is reached. At the time point when the predetermined power is reached, nitrogen is introduced into the reactor to restore the pressure, the generated polyester carbonate resin is extruded into water, and the bundles are cut to obtain pellets.

2-2. Preparation of retardation film The obtained polyester carbonate resin (pellets) was vacuum-dried at 80°C for 5 hours, and then used a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder set temperature: 250°C) and a T-die (width 200mm). , set temperature: 250℃), cooling roller (set temperature: 120~130℃) and film forming device of the winding machine to produce a long resin film with a thickness of 135μm. The obtained long 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 phase difference film with a thickness of 53 μm. The Re(550) of the obtained retardation film was 141 nm, Re(450)/Re(550) was 0.82, and the Nz coefficient was 1.12.

3. Make a polarizing plate with a phase difference layer The retardation film obtained in the above 2. was bonded to the surface of the polarizer of the polarizing plate obtained in the above 1. through an acrylic adhesive (thickness: 5 μm). At this time, the polarizer is bonded so that the absorption axis and the slow axis of the retardation film form an angle of 45°. And the same adhesive layer as in Example 1 is provided on the surface of the retardation layer. In the above manner, a polarizing plate with a retardation layer composed of a protective layer/adhesive layer/polarizer/adhesive layer/retardation layer (a stretched film of a resin film)/adhesive layer is obtained. The total thickness of the polarizing plate with the retardation layer obtained was 91 μm. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Table 1]

[Table 2]

[evaluate] It can be clearly seen from Table 1 that the polarizing plate with a retardation layer according to the embodiment of the present invention can significantly suppress the increase in reflectivity in a high temperature and high humidity environment by forming an iodine transmission inhibition layer with an iodine absorption index below a predetermined value. Furthermore, by forming the iodine transmission inhibiting layer, metal corrosion in a high-temperature and high-humidity environment can be significantly inhibited. Furthermore, as is apparent from Reference Example 1, the above-mentioned increase in reflectivity and metal corrosion are issues unique to extremely thin polarizing plates with retardation layers.

It can be clearly seen from Table 2 that the polarizing plates with retardation layers in Examples 9 to 12 of the present invention include two or three layers of iodine transmission inhibiting layers, even if they are put into use for a long time (200 hours) in a high temperature and high humidity environment. down, metal corrosion can still be significantly inhibited. Therefore, it can be seen that when the polarizing plates with retardation layers in Embodiments 9 to 12 of the present invention are used in image display devices, they can significantly inhibit corrosion of metal components.

industrial availability The polarizing plate with a retardation layer of the present invention can be suitably used as a circular polarizing plate for liquid crystal display devices, organic EL display devices and inorganic EL display devices.

10:Polarizing plate 11:Polarizer 12:Protective layer 20: Phase difference layer (first phase difference layer) 21: The first liquid crystal orientation solidification layer 22: The second liquid crystal orientation solidification layer 30: Adhesive layer 40: Iodine penetration inhibition layer 50: Another phase difference layer (second phase difference layer) 60: Conductive layer or isotropic substrate with conductive layer 100: Polarizing plate with phase difference layer 101: Polarizing plate with phase difference layer 102: Polarizing plate with phase difference layer 103: Polarizing plate with phase difference layer 104: Polarizing plate with phase difference layer 105: Polarizing plate with phase difference layer

1A is a schematic cross-sectional view of a polarizing plate with a retardation layer according to an embodiment of the present invention. 1B is a schematic cross-sectional view of a polarizing plate with a retardation layer according to another embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to yet another embodiment of the present invention. 3 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to yet another embodiment of the present invention. 4 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to yet another embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to yet another embodiment of the present invention.

10:Polarizing plate

11:Polarizer

12:Protective layer

20: Phase difference layer

30: Adhesive layer

40: Iodine penetration inhibition layer

100: Polarizing plate with phase difference layer

Claims (12)

A polarizing plate with a retardation layer, which has a polarizing plate including a polarizer, a retardation layer and an adhesive layer in order from the viewing side; the retardation layer is a directionally solidified layer of a liquid crystal compound, and the retardation layer is The polarizer is combined to exert a circular polarization function or an elliptical polarization function; the polarizer contains iodine; an iodine transmission inhibition layer is provided between the polarizer and the adhesive layer (excluding the orientation film used to orient the liquid crystal compound), The iodine transmission inhibition layer is composed of a thermoplastic resin soluble in an organic solvent; the iodine absorption index of the iodine transmission inhibition layer is less than 0.015; the resin constituting the iodine transmission inhibition layer includes a copolymer obtained by polymerizing a monomer mixture substance, and the monomer mixture contains more than 50 parts by weight of (meth)acrylic monomer and more than 0 parts by weight and less than 50 parts by weight of the monomer represented by formula (1):

(In the formula, At least one reactive group in the group consisting of an ether group, an epoxy group, an oxetanyl group, a hydroxyl group, an amine group, an aldehyde group and a carboxyl group. R ¹ and R ² each independently represent a hydrogen atom and may be substituted. The base is an aliphatic hydrocarbon group, an aryl group that may have a substituent, or a heterocyclic group that may have a substituent, and R ¹ and R ² may be connected to each other to form a ring). A polarizing plate with a retardation layer as claimed in claim 1, wherein the iodine transmission inhibiting layer is provided between the polarizer and the retardation layer. A polarizing plate with a retardation layer as claimed in claim 1, wherein the iodine transmission inhibiting layer is provided between the retardation layer and the adhesive layer. The polarizing plate with a retardation layer according to any one of claims 1 to 3, wherein the potassium absorption index of the iodine transmission inhibiting layer is 0.015 or less. The polarizing plate with a retardation layer according to any one of claims 1 to 3, wherein the glass transition temperature of the resin constituting the iodine transmission inhibiting layer is 85°C or above, and the weight average molecular weight Mw is 25,000 or above. The polarizing plate with a retardation layer as claimed in any one of claims 1 to 3, wherein the retardation layer is a single layer, Re(550) of the retardation layer is 100nm~190nm, and the slow axis of the retardation layer The angle formed with the absorption axis of the aforementioned polarizer is 40°~50°. The polarizing plate with a retardation layer as claimed in any one of claims 1 to 3, wherein the retardation layer has a laminated structure of a directionally solidified layer of a first liquid crystal compound and a directionally solidified layer of a second liquid crystal compound; the first liquid crystal The Re(550) of the orientationally solidified layer of the compound is 200nm~300nm, and the angle formed by the slow axis and the absorption axis of the aforementioned polarizer is 10°~20°; the Re(550) of the orientationally solidified layer of the second liquid crystal compound It is 100nm~190nm, and the angle formed by its slow axis and the absorption axis of the polarizer is 70°~80°. The polarizing plate with a retardation layer according to any one of claims 1 to 3, wherein there is another retardation layer between the aforementioned retardation layer and the aforementioned adhesive layer, and the refractive index characteristics of the other retardation layer Show the relationship nz>nx=ny. The polarizing plate with a retardation layer according to any one of claims 1 to 3, further comprising a conductive layer or an isotropic base material with a conductive layer between the iodine transmission inhibiting layer and the adhesive layer. For example, the polarizing plate with a phase difference layer according to any one of claims 1 to 3, the total thickness is within Below 60μm. An image display device provided with the polarizing plate with a phase difference layer according to any one of claims 1 to 10. For example, the image display device of claim 11 is an organic electroluminescent display device or an inorganic electroluminescent display device.