JP2022077101A - Method of manufacturing polarizing plate with retardation layer - Google Patents

Abstract

To provide a simple and efficient method of manufacturing a polarizing plate with a retardation layer having its warpage suppressed.SOLUTION: There is provided a method of manufacturing a polarizing plate with a retardation layer that has a polarizer, a protective layer arranged on one side of the polarizer, and the retardation layer arranged on the other side of the polarizer. The method includes: performing humidification processing while roll-conveying an intermediate laminate having a water-absorptive film stuck temporarily on a retardation layer side of the polarizing plate with the retardation layer; and storing the intermediate laminate after the humidification processing for 12 hours or longer, wherein the protective layer has a water vapor permeability of 100 g/m2 24h or shorter at 40°C and 92% RH, and the retardation layer is an orientation solidified layer of a liquid compound.SELECTED DRAWING: Figure 3

Description

The present invention relates to a method for manufacturing a polarizing plate with a retardation layer.

Image display devices represented by liquid crystal displays and electroluminescence (EL) display devices (for example, organic EL display devices and inorganic EL display devices) are rapidly becoming widespread. A polarizing plate and a retardation plate are typically used in an image display device. Practically, a polarizing plate with a retardation layer in which a polarizing plate and a retardation plate are integrated is widely used (for example, Patent Document 1). In recent years, the possibility of bending, bending, folding, and winding of an image display device has been studied, and there is a demand for a thinner image display device. Along with this, there is also a demand for a thinner polarizing plate with a retardation layer. However, the thin polarizing plate with a retardation layer has a problem that warpage is likely to occur. In particular, the problem of warpage is remarkable in a polarizing plate with a retardation layer, which has a protective layer having a small moisture permeability on only one side of the polarizing element and includes a retardation layer which is an orientation-solidifying layer of a liquid crystal compound.

Japanese Patent No. 3325560

The present invention has been made to solve the above-mentioned conventional problems, and a main object thereof is to provide a simple and efficient method for manufacturing a polarizing plate with a retardation layer in which warpage is suppressed.

According to an embodiment of the present invention, a polarizing plate with a retardation layer having a polarizing element, a protective layer arranged on one side of the polarizing element, and a retardation layer arranged on the other side of the polarizing element. Manufacturing method is provided. The manufacturing method involves humidifying an intermediate laminate having a water-absorbent film temporarily attached to the retard layer side of a polarizing plate with a retardation layer while transporting the rolls; the humidified intermediate laminate is stored for 12 hours or more. The protective layer has a moisture permeability of 100 g / ^m 2.24 h or less at 40 ° C. and 92% RH, and the retardation layer is an oriented solidified layer of a liquid crystal compound.
In one embodiment, the water absorption rate of the water-absorbent film is 2% or more. In one embodiment, the water-absorbent film is a triacetyl cellulose film. In one embodiment, the thickness of the water-absorbent film is 40 μm or more. In one embodiment, the water-absorbent film has a moisture permeability of 300 g / ^m 2.24 h or more at 40 ° C. and 92% RH.
In one embodiment, the humidification treatment is performed in an environment where the temperature is 34 ° C. or lower and the amount of water vapor is 13.8 g / m ³ or more. In one embodiment, the humidification time in the humidification treatment is 5 minutes or more.
In one embodiment, the storage time of the humidified intermediate laminate is 24 hours or more. In one embodiment, the humidified intermediate laminate is stored in an environment where the temperature is 34 ° C. or lower.
In one embodiment, the manufacturing method further comprises stripping and removing the water-absorbent film from the intermediate laminate after storage.
In one embodiment, the retardation layer has a moisture permeability of 300 g / ^m 2.24 h or more at 40 ° C. and 92% RH.
In one embodiment, the retardation layer is a single layer, the Re (550) of the retardation layer is 100 nm to 190 nm, and the Re (450) / Re (550) of the retardation layer is 0. It is 8 or more and less than 1, and the angle formed by the slow axis of the retardation layer and the absorption axis of the polarizing element is 40 ° to 50 °. In one embodiment, the polarizing plate with a retardation layer further has another retardation layer outside the retardation layer, and the refractive index characteristic of the other retardation layer has a relationship of nz> nx = ny. Is shown.
In one embodiment, the retardation layer has a laminated structure of an oriented solidified layer of a first liquid crystal compound and an oriented solidified layer of a second liquid crystal compound; an oriented solidified layer of the first liquid crystal compound. The Re (550) of the second liquid crystal compound is 200 nm to 300 nm, and the angle formed by the slow axis thereof and the absorption axis of the above-mentioned polarizing element is 10 ° to 20 °; the Re (550) of the oriented solidification layer of the second liquid crystal compound is formed. ) Is 100 nm to 190 nm, and the angle formed by the slow axis thereof and the absorption axis of the polarizing element is 70 ° to 80 °.
In one embodiment, the total thickness of the polarizing plate with a retardation layer is 45 μm or less.

According to the embodiment of the present invention, in the method for manufacturing a polarizing plate with a retardation layer, an intermediate laminate temporarily coated with a predetermined water-absorbent film is subjected to a predetermined humidification treatment, and the humidified intermediate laminate is predetermined. By storing for a long time, it is possible to easily and efficiently manufacture a polarizing plate with a retardation layer in which warpage is suppressed.

It is schematic cross-sectional view which shows an example of the polarizing plate with a retardation layer obtained by the manufacturing method by the Embodiment of this invention. It is schematic cross-sectional view which shows another example of the polarizing plate with a retardation layer obtained by the manufacturing method by Embodiment of this invention. It is a conceptual diagram for demonstrating the manufacturing method by Embodiment of this invention.

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

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

A. Schematic diagram of the configuration of the polarizing plate with a retardation layer obtained by the manufacturing method according to the embodiment of the present invention FIG. 1 is a schematic cross-sectional view showing an example of the polarizing plate with a retardation layer obtained by the manufacturing method according to the embodiment of the present invention. be. The polarizing plate 100 with a retardation layer in the illustrated example has a polarizing element 11, a protective layer 12 arranged on one side of the polarizing element 11 (typically, the viewing side), and the other side of the polarizing element 11. It has a retardation layer 20 arranged in the. That is, the polarizing plate 100 with a retardation layer has a protective layer 12 only on the visible side (opposite side of the retardation layer 20) of the polarizing element 11. In such a polarizing plate with a retardation layer, the effect (described later) according to the embodiment of the present invention can be remarkable. Practically, an adhesive layer (not shown) is provided on the opposite side of the retardation layer 20 from the polarizing element 11 (that is, as the outermost layer on the side opposite to the visual recognition side), and the polarizing plate with the retardation layer is an image. It can be pasted on the display panel. Further, it is preferable that a release film (not shown) is temporarily attached to the surface of the pressure-sensitive adhesive layer until the polarizing plate with a retardation layer is used. By temporarily attaching the release film, the pressure-sensitive adhesive layer can be protected and a roll of the polarizing plate with a retardation layer can be formed. In addition, in this specification, a laminated body of a polarizing element and a protective layer may be referred to as a polarizing plate.

In the embodiment of the present invention, the moisture permeability of the protective layer 12 at 40 ° C. and 92% RH (hereinafter, simply referred to as moisture permeability) is 100 g / ^m 2.24 h or less. In a polarizing plate with a retardation layer having such a protective layer having moisture permeability on only one side of the polarizing element, the effect (described later) according to the embodiment of the present invention can be remarkable. The moisture permeability of the protective layer is preferably 80 g / ^m 2.24 h or less, and more preferably 60 g / ^m 2.24 h or less. The lower limit of the moisture permeation may be, for example, ⁵ g / m 2.24 h.

In the embodiment of the present invention, the retardation layer 20 is an alignment solidification layer (liquid crystal alignment solidification layer) of a liquid crystal compound. By using a liquid crystal compound, the difference between nx and ny of the obtained retardation layer can be significantly increased as compared with the non-liquid crystal material, so that the thickness of the retardation layer for obtaining a desired in-plane retardation can be obtained. Can be made much smaller. Therefore, it is possible to realize a remarkable reduction in thickness of the polarizing plate with a retardation layer. In such a polarizing plate with a retardation layer, the effect (described later) according to the embodiment of the present invention can be remarkable. As used herein, the term "aligned solidified layer" refers to a layer in which a liquid crystal compound is oriented in a predetermined direction within the layer and the oriented state is fixed. The "oriented solidified layer" is a concept including an oriented cured layer obtained by curing a liquid crystal monomer as described later. In the retardation layer 20, the rod-shaped liquid crystal compounds are typically oriented in a state of being aligned in the slow axis direction of the retardation layer (homogeneous orientation). The retardation layer 20 may be a single layer as shown in FIG. 1, or may have a laminated structure of two or more layers as shown in FIG.

The moisture permeability of the retardation layer is preferably 300 g / ^m 2.24 h or more, more preferably 300 g / ^m 2.24 h to 1000 g / ^m 2.24 h, and further preferably 400 g / ^m 2.24 h to 800 g. / M ^2.24h . The difference between the moisture permeability of the protective layer and the moisture permeability of the retardation layer is preferably ²⁰⁰ g / m 2.24 h or more, and more preferably ²⁵⁰ g / m 2.24 h to 750 g / ^m 2.24 h.

The total thickness of the polarizing plate with a retardation layer (total thickness of the polarizing element, the protective layer, the retardation layer, and the adhesive layer in which these are laminated) is preferably 45 μm or less, more preferably 40 μm or less, and further preferably. Is 35 μm or less. The total thickness of the polarizing plate with a retardation layer can be, for example, 25 μm or more. Further, in a polarizing plate with a retardation layer, the ratio of the thickness of the polarizing plate (polarizer and the protective layer) to the thickness of the retardation layer (polarizing plate / retardation layer: hereinafter, may be simply referred to as "thickness ratio". ) Is preferably 5 or more, more preferably 5 to 16, and even more preferably 5 to 14. Such a thickness ratio can be realized by having a protective layer on only one side of the polarizing element, the retardation layer being an orientation-solidifying layer of the liquid crystal compound, and the thickness of the polarizing element being thin as described later.

The polarizing plate with a retardation layer may further include other optical functional layers. The type, characteristics, number, combination, arrangement position, and the like of the optical functional layers that can be provided on the polarizing plate with a retardation layer can be appropriately set according to the purpose. For example, the polarizing plate with a retardation layer may further have a conductive layer or an isotropic substrate with a conductive layer (neither is shown). The conductive layer or the isotropic base material with the conductive layer is typically provided on the outside of the retardation layer 20 (on the opposite side of the polarizing plate 10). The conductive layer or the isotropic base material with the conductive layer is typically any layer provided as needed, and may be omitted. When a conductive layer or an isotropic substrate with a conductive layer is provided, the polarizing plate with a retardation layer is a so-called inner in which a touch sensor is incorporated between an image display cell (for example, an organic EL cell) and the polarizing plate. It can be applied to a touch panel type input display device. Further, for example, the polarizing plate with a retardation layer may further include another retardation layer. The optical characteristics (for example, refractive index characteristics, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, arrangement position, and the like of the other retardation layer can be appropriately set according to the purpose. Further / or, if necessary, the surface of the protective layer 12 is provided with a layer (typically, a (elliptical) circular polarization function) for improving visibility when visually recognizing through polarized sunglasses. A plate, an ultra-high retardation layer) may be provided. With such a configuration, excellent visibility can be realized even when the display screen is visually recognized through a polarizing lens such as polarized sunglasses. Therefore, the polarizing plate with a retardation layer can be suitably applied to an image display device that can be used outdoors.

Hereinafter, a method for manufacturing a polarizing plate with a retardation layer as described above according to an embodiment of the present invention will be described, and then components of the polarizing plate with a retardation layer will be described.

B. Method for manufacturing a polarizing plate with a retardation layer In the method for manufacturing a polarizing plate with a retardation layer according to the embodiment of the present invention, an intermediate laminate in which a water-absorbent film is temporarily adhered to the retardation layer side of the polarizing plate with a retardation layer is formed. Moisturizing treatment while transporting by roll; storing the humidified intermediate laminate for 12 hours or more; Hereinafter, each step in the method for manufacturing a polarizing plate with a retardation layer will be described in order.

B-1. Fabrication of Polarizers Polarizers can be made by any suitable method. Specifically, the polarizing plate may contain a polarizing element made of a single-layer resin film, or may contain a polarizing element made of a laminated body having two or more layers.

B-1-1. Fabrication of a polarizing plate using a polarizing element obtained from a single-layer resin film A method for producing a polarizing plate from a single-layer resin film is typically a resin film with iodine, a dichroic dye, or the like. It includes performing a dyeing treatment with a chromatic substance and a stretching treatment. Examples of the resin film include a hydrophilic polymer film such as a polyvinyl alcohol (PVA) -based film, a partially formalized PVA-based film, and an ethylene / vinyl acetate copolymer-based partially saponified film. The method may further include insolubilization treatment, swelling treatment, cross-linking treatment and the like. A polarizing plate can be obtained by laminating a protective layer (protective film) on at least one of the obtained polarizing elements. Since such a manufacturing method is well-known and customary in the art, detailed description thereof will be omitted.

B-1-2. Manufacture of a Plate Plate Using a Polarizer Obtained from a Laminated Body When a laminated body is used for manufacturing a polarizing element, the laminated body is a resin base material and a PVA-based resin layer (PVA-based) laminated on the resin base material. It may be a laminate with a resin film), or it may be a laminate of a resin base material and a PVA-based resin layer coated and formed on the resin base material. As an example, a method for manufacturing a polarizing element using a laminate of a resin base material and a PVA-based resin layer coated and formed on the resin base material will be described. In the manufacturing method, typically, a PVA-based resin solution is applied to a resin base material and dried to form a PVA-based resin layer on the resin base material, and the resin base material and the PVA-based resin layer are laminated. Obtaining a body; stretching and dyeing the laminate to make a PVA-based resin layer a stator; In such a production method, a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin is preferably formed on one side of the resin base material. Stretching typically involves immersing the laminate in an aqueous boric acid solution for stretching. Further, stretching may further comprise, if necessary, stretching the laminate in the air at a high temperature (eg, 95 ° C. or higher) prior to stretching in boric acid aqueous solution. In addition, in such a manufacturing method, preferably, the laminate is subjected to a drying shrinkage treatment in which the laminate is shrunk by 2% or more in the width direction by heating while being conveyed in the longitudinal direction. Typically, the production method includes subjecting the laminate to an aerial auxiliary stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment in this order. By introducing the auxiliary stretching, even when PVA is applied on the thermoplastic resin, the crystallinity of PVA can be enhanced and high optical characteristics can be achieved. At the same time, by increasing the orientation of PVA in advance, it is possible to prevent problems such as deterioration of PVA orientation and dissolution when immersed in water in a subsequent dyeing step or stretching step, and high optical characteristics. Will be possible to achieve. Further, when the PVA-based resin layer is immersed in a liquid, the disorder of the orientation of the polyvinyl alcohol molecule and the decrease in the orientation can be suppressed as compared with the case where the PVA-based resin layer does not contain a halide. This makes it possible to improve the optical characteristics of the polarizing element obtained through a treatment step of immersing the laminate in a liquid, such as a dyeing treatment and a stretching treatment in water. Further, the optical characteristics can be improved by shrinking the laminated body in the width direction by the drying shrinkage treatment. The obtained resin base material / polarizing element laminate may be used as it is (that is, the resin base material may be used as a protective layer for the polarizing element), and the resin base material is peeled off from the resin base material / polarizing element laminate. Then, an arbitrary appropriate protective layer according to the purpose may be laminated on the peeled surface and used. Details of the method for producing such a polarizing element are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580 and Japanese Patent No. 6470455. The entire description of these publications is incorporated herein by reference.

B-2. Formation of a retardation layer A method for forming a retardation layer (liquid crystal oriented solidified layer) will be briefly described. In the liquid crystal alignment solidified layer, the surface of a predetermined base material is subjected to an orientation treatment, and a coating liquid containing a liquid crystal compound is applied to the surface to orient the liquid crystal compound in a direction corresponding to the alignment treatment. It can be formed by fixing the state. As the orientation treatment, any appropriate orientation treatment can be adopted. Specific examples thereof include mechanical orientation treatment, physical orientation treatment, and chemical orientation treatment. Specific examples of the mechanical orientation treatment include a rubbing treatment and a stretching treatment. Specific examples of the physical orientation treatment include magnetic field orientation treatment and electric field orientation treatment. Specific examples of the chemical alignment treatment include an orthorhombic vapor deposition method and a photoalignment treatment. As the treatment conditions for various orientation treatments, any appropriate conditions may be adopted depending on the purpose.

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

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

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

As described above, the liquid crystal oriented solidified layer is formed on the base material.

B-3. Fabrication of Polarizing Plate with Phase Difference Layer A polarizing plate with a retardation layer can be obtained by laminating the polarizing plate obtained above and the retardation layer. The lamination of the polarizing plate and the retardation layer is typically performed while transporting them in a roll (that is, by so-called roll-to-roll). Lamination can be typically performed by transferring a liquid crystal oriented solidified layer formed on the substrate. When the retardation layer has a laminated structure, each retardation layer may be sequentially laminated (transferred) on the polarizing plate, or the laminated body of the retardation layer may be laminated (transferred) on the polarizing plate. Transfer is typically carried out via an active energy ray-curable adhesive. The thickness of the active energy ray-curable adhesive after curing is preferably 0.4 μm or more, more preferably 0.4 μm to 3.0 μm, and further preferably 0.6 μm to 1.5 μm.

If the polarizing plate with a retardation layer further includes other optical functional layers (eg, a conductive layer, another retardation layer), these optical functional layers are laminated or formed in a predetermined arrangement position by any suitable method. obtain.

The production (lamination) of the polarizing plate with a retardation layer is typically performed in an environment where the amount of water vapor is 11.5 g / m ³ or less. The amount of water vapor in the lamination is preferably 6.0 g / m ³ to 11.5 g / m ³ , and more preferably 8.0 g / m ³ to 11.5 g / m ³ . By laminating in an environment where the amount of water vapor is in such a range, the effect of the humidification treatment described later becomes remarkable. Such an amount of water vapor in the lamination can be realized, for example, by changing the relative humidity according to the temperature in the temperature range of 18 ° C. to 25 ° C. The amount of water vapor can be achieved, for example, by setting the relative humidity to 65% RH or less when the temperature is 18 ° C; and also, for example, when the temperature is 20 ° C, the relative humidity is 55% RH. It can be realized by setting the relative humidity to 45% RH or less, for example, when the temperature is 23 ° C. The lower limit of relative humidity can be, for example, 30% RH.

B-4. Preparation of Intermediate Laminated Body Next, as shown in FIG. 3, the water-absorbent film 150 is temporarily attached to the retardation layer side of the polarizing plate with the retardation layer obtained above to prepare the intermediate laminate 200. The intermediate laminate is produced by roll-to-roll in the same manner as described above. The polarizing plate with a retardation layer at the time of producing the intermediate laminate has the same layer structure as the polarizing plate with a retardation layer finally obtained, but is substantially an intermediate, so that it is shown in FIG. The intermediate corresponding to the polarizing plate with a retardation layer 100 in FIG. 1 is indicated by reference numeral 100', and the intermediate corresponding to the polarizing plate with a retardation layer 101 in FIG. 2 is indicated by reference numeral 101'.

The water absorption rate of the water-absorbent film is preferably 2% or more, more preferably 2% to 20%, still more preferably 2% to 10%. When the water absorption rate of the water-absorbent film is within such a range, the amount of water that can reach the polarizing element can be adjusted to an appropriate range by the humidification treatment and storage after the humidification treatment (both described later). More specifically, the water-absorbent film can absorb an appropriate amount of water by the humidification treatment and retain a predetermined amount of the absorbed water. Moisture retained in the water-absorbent film can transfer to the polarizing element during storage. Therefore, the conditions of the humidification treatment are appropriately set to adjust the amount of water absorbed and retained in the water-absorbent film, and the storage conditions are appropriately adjusted to adjust the amount of water transferred from the water-absorbent film to the polarizing element. By doing so, the water content of the polarizing element can be set in an appropriate range. As a result, the warp of the polarizing plate with a retardation layer can be remarkably suppressed. If the water absorption rate is too low, the suppression of warpage may be insufficient. If the water absorption is too high, warpage may occur in the opposite direction and / or in the plane in a direction orthogonal to the initial direction. More specifically, if the humidification treatment is not performed, the polarizing plate with a retardation layer typically causes a convex warp on the protective layer side. On the other hand, by performing the humidification treatment, a convex warp is generated on the retardation layer side. As a result, the warpage in the opposite directions is canceled out, so that the warp can be suppressed in the obtained polarizing plate with a retardation layer. Therefore, if the water absorption rate is too high, the convex warp toward the retardation layer side becomes too large, and the obtained polarizing plate with the retardation layer has the opposite direction (convex toward the protective layer side) and / or the initial direction in the plane. Can cause warpage in orthogonal directions.

The water-absorbent film can be made of any suitable material as long as it has the above-mentioned desired water absorption rate. Examples of the material constituting the water-absorbent film include triacetyl cellulose (TAC) and an acrylic resin. TAC is preferable.

The thickness of the water-absorbent film is preferably 40 μm or more, more preferably 60 μm or more, and further preferably 70 μm or more. The upper limit of the thickness of the water-absorbent film can be, for example, 200 μm. If the thickness of the water-absorbent film is within such a range, the amount of water that can reach the polarizing element in the humidification treatment can be adjusted to an appropriate range by a synergistic effect with the effect of setting the water absorption rate within a predetermined range. Therefore, storage after the humidification treatment can bring the water content of the stator to an appropriate range. As a result, the warp of the polarizing plate with a retardation layer can be remarkably suppressed.

The moisture permeability of the water-absorbent film is preferably 300 g / ^m 2.24 h or more, more preferably 300 g / ^m 2.24 h to 1000 g / ^m 2.24 h, and further preferably 300 g / ^m 2.24 h to 800 g. / M ^2.24h . If the moisture permeability of the water-absorbent film is within such a range, an appropriate amount of the water absorbed by the water-absorbent film by the humidification treatment and retained in the water-absorbent film becomes a polarizing element by storage after the humidification treatment. Can be migrated. Therefore, by storing after the humidification treatment, the water content of the polarizing element can be set in an appropriate range. As a result, the warp of the polarizing plate with a retardation layer can be remarkably suppressed.

The production (lamination) of the intermediate laminate can be typically performed in the same environment as the production (lamination) of the polarizing plate with a retardation layer.

B-5. Humidification treatment As shown in FIG. 3, the intermediate laminate 200 obtained above is subjected to a humidification treatment. The humidification treatment is typically performed while the intermediate laminate is being rolled and conveyed. The humidification treatment is typically performed in an environment where the temperature is 34 ° C. or lower and the amount of water vapor is 13.8 g / m ³ or more. The temperature in the humidification treatment is preferably 18 ° C to 34 ° C. The amount of water vapor in the humidification treatment is preferably 13.8 g / m ³ to 30 g / m ³ , and more preferably 13.8 g / m ³ to 24 g / m ³ . Such an amount of water vapor in the humidification treatment can be achieved, for example, by setting the relative humidity to 80% RH or higher when the temperature is 20 ° C; and also, for example, when the temperature is 23 ° C. It can be achieved by setting the relative humidity to 70% RH or higher; and for example, if the temperature is 25 ° C, it can be achieved by setting the relative humidity to 60% RH or higher; and for example, the temperature is 28 ° C. If so, it can be achieved by increasing the relative humidity to more than 50% RH. The upper limit of relative humidity can be, for example, 100% RH. By performing the humidification treatment under such conditions, an appropriate amount of water is imparted to the polarizing plate with a retardation layer, and the phase difference is synergistic with the effect of temporarily adhering the water-absorbent film. It is possible to suppress the warp of the layered polarizing plate.

The humidification time in the humidification treatment is preferably 5 minutes or more, more preferably 5 minutes to 30 minutes, still more preferably 5 minutes to 20 minutes, and particularly preferably 5 minutes to 15 minutes. If the humidification time is 5 minutes or more, the desired amount of water absorption can be achieved. Since the effect does not change even if the humidification time becomes excessively long, the upper limit of the humidification time can be determined by the balance between the desired amount of water absorption and the production efficiency.

The humidification treatment is performed so that the weight per unit volume of the polarizing plate with a retardation layer is increased by, for example, 0.2% or more. The weight increase per unit volume of the polarizing plate with a retardation layer in the humidification treatment is preferably 0.2% to 2.5%, more preferably 0.3% to 2.0%, still more preferably. It is 0.3% to 1.0%. The weight increase in the humidification treatment means that the polarizing plate with a retardation layer has absorbed water. Therefore, by setting the weight increase amount in such a range, the polarizing element can absorb a desired amount of water. .. As a result, the warp of the polarizing plate with a retardation layer can be suppressed.

B-6. Storage The humidified intermediate laminate is stored as shown in FIG. Typically, the intermediate laminate is wound into a roll and stored in a roll state. By such storage, the moisture imparted to the intermediate laminate (substantially, the water-absorbent film) by the humidification treatment can be satisfactorily transferred to the polarizing element. As a result, the water content of the polarizing element can be increased, and as a result, the warp of the polarizing plate with a retardation layer can be suppressed. The storage time is 12 hours or more, preferably 16 hours or more, more preferably 24 hours or more, still more preferably 30 hours or more, as described above. Since the effect does not change even if the storage time becomes excessively long, the upper limit of the storage time can be determined by the balance between the desired amount of water absorption and the production efficiency.

Storage can typically be done near room temperature. The temperature in storage is typically 34 ° C. or lower, preferably 30 ° C. or lower, more preferably 20 ° C. to 30 ° C., and even more preferably 23 ° C. to 27 ° C. If the storage temperature is too high, the water imparted (absorbed) to the polarizing plate with a retardation layer by the humidification treatment evaporates to the outside, and may not be transferred to the polarizing element satisfactorily.

Storage is typically carried out in an environment where the amount of water vapor is 11.5 g / m ³ or less. In other words, storage takes place without substantially humidifying the intermediate laminate. By storing in such an environment, moisture can be satisfactorily transferred from the water-absorbent film to the polarizing element.

After storage, the water-absorbent film is stripped and removed from the intermediate laminate as shown in FIG. In this way, a polarizing plate with a retardation layer can be obtained.

C. Polarizing plate C-1. Polarizer As is clear from the above manufacturing method, the splitter 11 is typically a resin film containing a dichroic substance (for example, iodine). As described above, examples of the resin film include a hydrophilic polymer film such as a polyvinyl alcohol (PVA) -based film, a partially formalized PVA-based film, and an ethylene / vinyl acetate copolymer-based partially saponified film.

The thickness of the splitter is preferably 15 μm or less, more preferably 1 μm to 12 μm, and even more preferably 3 μm to 12 μm. When the thickness of the polarizing element is within such a range, a desired amount of water can be satisfactorily absorbed by the humidification treatment as described above.

The splitter preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The simple substance transmittance of the substituent is, for example, 41.5% to 46.0%, preferably 42.0% to 46.0%, and preferably 44.5% to 46.0%. The degree of polarization of the polarizing element is preferably 97.0% or more, more preferably 99.0% or more, and further preferably 99.9% or more.

C-2. Protective layer The protective layer 12 is formed of any suitable film that can be used as a protective layer for a polarizing element as long as it has the above-mentioned moisture permeability. Specific examples of the material that is the main component of the film include polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, polysulfone-based, polystyrene-based, and cyclic olefin-based (for example, polynorbornene-based). ), Polyolefin-based, (meth) acrylic-based, acetate-based transparent resins and the like. Preferably, the protective layer 12 may be composed of a cyclic olefin-based (eg, polynorbornene-based) resin film.

The polarizing plate with a retardation layer obtained by the manufacturing method of the embodiment of the present invention is typically arranged on the visible side of an image display device, and the protective layer 12 is arranged on the visible side thereof. Therefore, the protective layer 12 may be subjected to surface treatment such as hard coat treatment, antireflection treatment, sticking prevention treatment, and antiglare treatment, if necessary.

The thickness of the protective layer 12 is preferably 5 μm to 80 μm, more preferably 10 μm to 40 μm, and even more preferably 15 μm to 35 μm. When the surface treatment is applied, the thickness of the protective layer 12 is the thickness including the thickness of the surface treatment layer.

D. Phase difference layer As described above, the phase difference layer 20 may be a single layer or may have a laminated structure of two or more layers.

When the retardation layer 20 is a single layer, the retardation layer can function as a λ / 4 plate in one embodiment. Specifically, the Re (550) of the retardation layer is preferably 100 nm to 180 nm, more preferably 110 nm to 170 nm, and further preferably 110 nm to 160 nm. The thickness of the retardation layer can be adjusted to obtain the desired in-plane retardation of the λ / 4 plate. The thickness of the retardation layer can be, for example, 1.0 μm to 2.5 μm. In the present embodiment, the angle formed by the slow axis of the retardation layer and the absorption axis of the polarizing element is preferably 40 ° to 50 °, more preferably 42 ° to 48 °, and further preferably 44. ° to 46 °. When the retardation layer is a single layer, the retardation layer preferably exhibits a reverse dispersion wavelength characteristic in which the retardation value increases with the wavelength of the measurement light. In this embodiment, the polarizing plate with a retardation layer has another retardation layer (not shown) showing a refractive index characteristic of nz> nz = ny on the outside of the retardation layer 20 (opposite to the polarizing element). You may also have more.

When the retardation layer 20 has a laminated structure, the retardation layer typically has a two-layer structure of an H layer 21 and a Q layer 22 in order from the polarizing plate side as shown in FIG. The H layer can typically function as a λ / 2 plate, and the Q layer can typically function as a λ / 4 plate. Specifically, the Re (550) of the H layer is preferably 200 nm to 300 nm, more preferably 220 nm to 290 nm, still more preferably 230 nm to 280 nm; and the Re (550) of the Q layer is preferably. It is 100 nm to 180 nm, more preferably 110 nm to 170 nm, and even more preferably 110 nm to 150 nm. The thickness of the H layer can be adjusted to obtain the desired in-plane phase difference of the λ / 2 plate. The thickness of the H layer can be, for example, 2.0 μm to 4.0 μm. The thickness of the Q layer can be adjusted to obtain the desired in-plane phase difference of the λ / 4 plate. The thickness of the Q layer can be, for example, 1.0 μm to 2.5 μm. In the present embodiment, the angle formed by the slow axis of the H layer and the absorption axis of the polarizing element is preferably 10 ° to 20 °, more preferably 12 ° to 18 °, and even more preferably 12 °. The angle between the slow axis of the Q layer and the absorption axis of the stator is preferably 70 ° to 80 °, more preferably 72 ° to 78 °, and even more preferably 72 °. It is ~ 76 °. The arrangement order of the H layer and the Q layer may be reversed, and the angle formed by the slow axis of the H layer and the absorption axis of the stator and the slow axis of the Q layer and the absorption axis of the splitter are formed. The angles may be reversed. When the retardation layer has a laminated structure, each layer (for example, H layer and Q layer) may exhibit a reverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light, and the retardation value may be exhibited. May show a positive wavelength dispersion characteristic that decreases according to the wavelength of the measurement light, or may show a flat wavelength dispersion characteristic in which the phase difference value hardly changes depending on the wavelength of the measurement light.

The retardation layer (each layer in the case of having a laminated structure) typically shows a relationship in which the refractive index characteristic is nx> ny = nz. It should be noted that "ny = nz" includes not only the case where ny and nz are completely equal, but also the case where they are substantially equal. Therefore, ny> nz or ny <nz may occur within a range that does not impair the effect of the present invention. The Nz coefficient of the retardation layer is preferably 0.9 to 1.5, and more preferably 0.9 to 1.3.

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

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

The temperature range in which the liquid crystal monomer exhibits liquid crystallinity differs depending on the type. Specifically, the temperature range is preferably 40 ° C. to 120 ° C., more preferably 50 ° C. to 100 ° C., and most preferably 60 ° C. to 90 ° C.

As the liquid crystal monomer, any suitable liquid crystal monomer can be adopted. For example, the polymerizable mesogen compounds described in Special Tables 2002-533742 (WO00 / 37585), EP358208 (US5211877), EP66137 (US43884553), WO93 / 22397, EP0261712, DE19504224, DE4408171, and GB2280445 can be used. Specific examples of such a polymerizable mesogen compound include, for example, BASF's trade name LC242, Merck's trade name E7, and Wacker-Chem's trade name LC-Silicon-CC3767. As the liquid crystal monomer, for example, a nematic liquid crystal monomer is preferable.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. The measurement method of each characteristic is as follows. Unless otherwise specified, "parts" and "%" in Examples and Comparative Examples are based on weight.
(1) Warping The polarizing plates with retardation layers obtained in the examples and comparative examples are 140 mm × 70 mm in size before humidification treatment (before preparation of the intermediate laminate) and after humidification / storage (after peeling the TAC film). Cut out to. At this time, the stator was cut out so that the absorption axis direction was the long side direction. When the cut-out polarizing plate with a retardation layer was allowed to stand on a plane, the height of the highest portion from the plane was defined as the amount of warpage.
Next, the amount of warpage of the polarizing plate with a retardation layer cut out after storage was measured in the same manner as described above, and the change in the amount of warpage before the humidification treatment and after humidification / storage was evaluated according to the following criteria.
◯: The change in the amount of warpage is ± 25 mm or less ×: The change in the amount of warpage is greater than ± 25 mm. Is represented by "negative (-)". Further, the stationary surface side is the retardation layer (Q layer) side.

[Example 1]
1. 1. Fabrication of Polarizing Plate As a thermoplastic resin base material, an amorphous isophthal copolymerized polyethylene terephthalate film (thickness: 100 μm) having a Tg of about 75 ° C. was used, and one side of the resin base material was treated with corona. Was given.
100 parts by weight of PVA-based resin in which polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gosefimer") are mixed at a ratio of 9: 1. A PVA aqueous solution (coating solution) was prepared by dissolving 13 parts by weight of potassium iodide in water.
The PVA aqueous solution was applied to the corona-treated surface of the resin base material and dried at 60 ° C. to form a PVA-based resin layer having a thickness of 13 μm, and a laminate was prepared.
The obtained laminate was uniaxially stretched 2.4 times in the vertical direction (longitudinal direction) in an oven at 130 ° C. (aerial auxiliary stretching treatment).
Next, the laminate was immersed in an insolubilizing bath at a liquid temperature of 40 ° C. (a boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insolubilization treatment).
Next, in a dyeing bath having a liquid temperature of 30 ° C. (an aqueous iodine solution obtained by mixing iodine and potassium iodide in a weight ratio of 1: 7 with respect to 100 parts by weight of water), the polarizing element finally obtained is charged. It was immersed for 60 seconds while adjusting the concentration so that the simple substance transmittance (Ts) became a desired value (staining treatment).
Then, it was immersed in a cross-linked bath having a liquid temperature of 40 ° C. (a boric acid aqueous solution obtained by blending 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with respect to 100 parts by weight of water) for 30 seconds. (Crossing treatment).
Then, while immersing the laminate in a boric acid aqueous solution (boric acid concentration 4% by weight, potassium iodide concentration 5% by weight) at a liquid temperature of 70 ° C., the total in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds. Uniaxial stretching was performed so that the stretching ratio was 5.5 times (underwater stretching treatment).
Then, the laminate was immersed in a washing bath having a liquid temperature of 20 ° C. (an aqueous solution obtained by blending 4 parts by weight of potassium iodide with 100 parts by weight of water) (cleaning treatment).
Then, while drying in an oven kept at about 90 ° C., it was brought into contact with a heating roll made of SUS whose surface temperature was kept at about 75 ° C. (dry shrinkage treatment).
In this way, a polarizing element having a thickness of about 5 μm was formed on the resin substrate, and a polarizing plate having a resin substrate / polarizing element configuration was obtained.

Further, an HC-COP film was attached to the surface of the obtained polarizing element (the surface opposite to the resin base material) as a protective layer on the visible side via an ultraviolet curable adhesive. The HC-COP film is a film in which an HC layer (thickness 2 μm) is formed on a cycloolefin resin (COP) film (thickness 25 μm), and the COP film is bonded so as to be on the splitter side. Next, the resin base material was peeled off to obtain a polarizing plate having an HC-COP film (visible side protective layer) / polarizing element. The moisture permeability of the protective layer on the visual recognition side was 100 g / ^m 2.24 h.

ポリエチレンテレフタレート（ＰＥＴ）フィルム（厚み３８μｍ）表面を、ラビング布を用いてラビングし、配向処理を施した。配向処理の方向は、偏光板に貼り合わせる際に偏光子の吸収軸の方向に対して視認側から見て１５°方向となるようにした。この配向処理表面に、上記液晶塗工液をバーコーターにより塗工し、９０℃で２分間加熱乾燥することによって液晶化合物を配向させた。このようにして形成された液晶層に、メタルハライドランプを用いて１ｍＪ/ｃｍ^２の光を照射し、当該液晶層を硬化させることによって、ＰＥＴフィルム上に液晶配向固化層Ａを形成した。液晶配向固化層Ａの厚みは２．０μｍ、面内位相差Ｒｅ（５５０）は２７０ｎｍであった。さらに、液晶配向固化層Ａは、ｎｘ＞ｎｙ＝ｎｚの屈折率特性を示した。液晶配向固化層ＡをＨ層として用いた。
塗工厚みを変更したこと、および、配向処理方向を偏光子の吸収軸の方向に対して視認側から見て７５°方向となるようにしたこと以外は上記と同様にして、ＰＥＴフィルム上に液晶配向固化層Ｂを形成した。液晶配向固化層Ｂの厚みは１．０μｍ、面内位相差Ｒｅ（５５０）は１４０ｎｍであった。さらに、液晶配向固化層Ｂは、ｎｘ＞ｎｙ＝ｎｚの屈折率特性を示した。液晶配向固化層ＢをＱ層として用いた。 2. 2. Fabrication of polarizing plate with retardation layer 2-1. Preparation of Phase Difference Layer 10 g of a polymerizable liquid crystal (manufactured by BASF: trade name "Pariocolor LC242", represented by the following formula) showing a nematic liquid crystal phase and a photopolymerization initiator for the polymerizable liquid crystal compound (manufactured by BASF:: A liquid crystal composition (coating liquid) was prepared by dissolving 3 g of the trade name "Irgacure 907") in 40 g of toluene.

The surface of a polyethylene terephthalate (PET) film (thickness 38 μm) was rubbed with a rubbing cloth and subjected to an orientation treatment. The direction of the alignment treatment was set to be 15 ° when viewed from the visual recognition side with respect to the direction of the absorption axis of the polarizing element when the polarizing plate was attached. The liquid crystal coating liquid was applied to the alignment-treated surface with a bar coater, and the liquid crystal compound was oriented by heating and drying at 90 ° C. for 2 minutes. The liquid crystal layer thus formed was irradiated with light of 1 mJ / cm ² using a metal halide lamp, and the liquid crystal layer was cured to form a liquid crystal oriented solidified layer A on a PET film. The thickness of the liquid crystal oriented solidified layer A was 2.0 μm, and the in-plane retardation Re (550) was 270 nm. Further, the liquid crystal oriented solidified layer A showed a refractive index characteristic of nx> ny = nz. The liquid crystal oriented solidified layer A was used as the H layer.
On the PET film in the same manner as above, except that the coating thickness was changed and the orientation processing direction was set to be 75 ° when viewed from the visual side with respect to the direction of the absorber's absorption axis. The liquid crystal oriented solidified layer B was formed. The thickness of the liquid crystal oriented solidified layer B was 1.0 μm, and the in-plane retardation Re (550) was 140 nm. Further, the liquid crystal oriented solidified layer B exhibited a refractive index characteristic of nx> ny = nz. The liquid crystal alignment solidification layer B was used as the Q layer.

2-2. Fabrication of polarizing plate with retardation layer 1. The above 2-1. The liquid crystal oriented solidified layer A (H layer) and the liquid crystal oriented solidified layer B (Q layer) obtained in 1) were transferred in this order. At this time, the angle between the absorption axis of the splitter and the slow axis of the oriented solidification layer A is 15 °, and the angle between the absorption axis of the splitter and the slow axis of the oriented solidification layer B is 75 °. Transferred (bonded). Each transfer (bonding) was performed via an ultraviolet curable adhesive (thickness 1.0 μm). In this way, a polarizing plate with a retardation layer having a structure of a protective layer / adhesive / polarizing element / adhesive / retardation layer (H layer) / adhesive / retardation layer (Q layer) was obtained. The total thickness of the polarizing plate with a retardation layer was 38 μm. The transfer (bonding) was performed while transporting the rolls.

3. 3. Preparation of intermediate laminate 2. A TAC film (thickness 70 μm) was temporarily attached to the surface of the Q layer of the polarizing plate with a retardation layer obtained in 1 above via an acrylic pressure-sensitive adhesive to prepare an intermediate laminate. The intermediate laminate was produced while being transported by roll. The water absorption rate of the TAC film was 5%, and the moisture permeability was 400 g / ^m 2.24 h.

4. Humidification treatment and storage 3. The intermediate laminate obtained in 1) was subjected to a humidification treatment while being transported by roll. The humidification treatment was carried out at 23 ° C. and 70% RH (water vapor amount was 14.4 g / m ³ ) for 10 minutes. The humidified polarizing plate with a retardation layer was wound into a roll, and the roll was stored at 23 ° C. and 55% RH (water vapor content: 11.3 g / m ³ ) for 24 hours. The polarizing plates with a retardation layer before the humidification treatment and after the roll storage were subjected to the evaluation of (1) above, respectively. The results are shown in Table 1.

[Example 2]
A polarizing plate with a retardation layer was obtained in the same manner as in Example 1 except that the humidification treatment was carried out at 20 ° C. and 80% RH (water vapor amount was 13.8 / m ³ ) for 10 minutes. The polarizing plates with a retardation layer before the humidification treatment and after the roll storage were subjected to the same evaluation as in Example 1, respectively. The results are shown in Table 1.

[Comparative Example 1]
A polarizing plate with a retardation layer was obtained in the same manner as in Example 1 except that the humidification treatment and the roll storage were performed without laminating the TAC film. The polarizing plates with a retardation layer before the humidification treatment and after the roll storage were subjected to the same evaluation as in Example 1, respectively. The results are shown in Table 1.

[Comparative Example 2]
A polarizing plate with a retardation layer (before the production of the intermediate laminate) was obtained in the same manner as in Example 1. The polarizing plate with a retardation layer was stored as it was (that is, without producing an intermediate laminate or subjected to a humidification treatment) and stored in a roll in the same manner as in Example 1. The polarizing plates with a retardation layer after roll storage were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[Reference Example 1]
A long roll of a PVA-based resin film having a thickness of 30 μm is uniaxially stretched in the long direction so that the total stretching ratio becomes 6.0 times by a roll stretching machine, and at the same time, it is swelled, dyed, crosslinked and washed. Finally, a dehydrator having a thickness of 12 μm was produced by subjecting it to a drying treatment. An HC-COP film was attached to one surface of the obtained polarizing element as a protective layer on the visual recognition side in the same manner as in Example 1. Further, a TAC film (thickness 25 μm) is attached to the other surface of the polarizing element via a PVA-based adhesive to have a protective layer (HC-COP film) / polarizing element / protective layer (TAC film). A polarizing plate was obtained. The following procedure is the same as in Example 1, and the protective layer (HC-COP film) / adhesive / polarizing element / adhesive / protective layer (TAC film) / adhesive / retardation layer (H layer) / adhesive. / A polarizing plate with a retardation layer having a configuration of a retardation layer (Q layer) was obtained. The total thickness of the polarizing plate with a retardation layer was 71 μm.

The following procedure was the same as in Example 1, and an intermediate laminate was prepared, the intermediate laminate was subjected to a humidification treatment, and then stored in a roll. The polarizing plates with a retardation layer before the humidification treatment and after the roll storage were subjected to the same evaluation as in Example 1, respectively. The results are shown in Table 1.

[evaluation]
As is clear from Table 1, the polarizing plate with a retardation layer obtained by the embodiment of the present invention is warped by subjecting the intermediate laminate to which the water-absorbent film is bonded to a predetermined humidification treatment and roll storage. It can be seen that it is suppressed. Further, as is clear from the reference example, it can be seen that such a warp is a problem peculiar to a polarizing plate with a retardation layer having a visible side protective layer having a thin total thickness and a small moisture permeability.

The polarizing plate with a retardation layer obtained by the manufacturing method of the embodiment of the present invention is used as a polarizing plate with a retardation layer for an image display device, and is particularly curved, bendable, foldable, or windable. It can be suitably used for an image display device (such an image display device typically uses a resin substrate as a substrate). Typical examples of the image display device include a liquid crystal display device, an organic EL display device, and an inorganic EL display device.

11 Polarizer 12 Protective layer 20 Phase difference layer 21 Phase difference layer (H layer)
22 Phase difference layer (Q layer)
100 Polarizing plate with retardation layer 100'Polarizer with retardation layer (intermediate)
101 Polarizing plate with retardation layer 101'Polarizer with retardation layer (intermediate)
150 Water-absorbent film 200 Intermediate laminate

Claims (15)

A method for manufacturing a polarizing plate with a retardation layer, which comprises a polarizing element, a protective layer arranged on one side of the polarizing element, and a retardation layer arranged on the other side of the polarizing element.
Humidification treatment is performed while transporting an intermediate laminate temporarily coated with a water-absorbent film on the retardation layer side of the polarizing plate with a retardation layer.
Store the humidified intermediate laminate for 12 hours or more;
Including
The moisture permeability of the protective layer at 40 ° C. and 92% RH is 100 g / ^m 2.24 h or less.
The retardation layer is an orientation-solidified layer of a liquid crystal compound.
Production method. The method for manufacturing a polarizing plate with a retardation layer according to claim 1, wherein the water absorption rate of the water-absorbent film is 2% or more. The method for producing a polarizing plate with a retardation layer according to claim 2, wherein the water-absorbent film is a triacetyl cellulose film. The method for manufacturing a polarizing plate with a retardation layer according to claim 3, wherein the water-absorbent film has a thickness of 40 μm or more. The method for producing a polarizing plate with a retardation layer according to claim 4, wherein the water-absorbent film has a moisture permeability of 300 g / ^m 2.24 h or more at 40 ° C. and 92% RH. The method for producing a polarizing plate with a retardation layer according to any one of claims 1 to 5, wherein the humidification treatment is performed in an environment where the temperature is 34 ° C. or lower and the amount of water vapor is 13.8 g / m ³ or more. The method for manufacturing a polarizing plate with a retardation layer according to claim 6, wherein the humidification time in the humidification treatment is 5 minutes or more. The method for manufacturing a polarizing plate with a retardation layer according to any one of claims 1 to 7, wherein the humidified intermediate laminate has a storage time of 24 hours or more. The method for manufacturing a polarizing plate with a retardation layer according to any one of claims 1 to 8, wherein the humidified intermediate laminate is stored in an environment where the temperature is 34 ° C. or lower. The method for producing a polarizing plate with a retardation layer according to any one of claims 1 to 9, further comprising peeling and removing the water-absorbent film from the intermediate laminate after the storage. The method for manufacturing a polarizing plate with a retardation layer according to any one of claims 1 to 10, wherein the retardation layer has a moisture permeability of 300 g / ^m 2.24 hours or more at 40 ° C. and 92% RH. The retardation layer is a single layer, the Re (550) of the retardation layer is 100 nm to 190 nm, and the Re (450) / Re (550) of the retardation layer is 0.8 or more and less than 1. The method for manufacturing a polarizing plate with a retardation layer according to any one of claims 1 to 11, wherein the angle formed by the slow axis of the retardation layer and the absorption axis of the polarizing element is 40 ° to 50 °. The twelfth claim, wherein the polarizing plate with a retardation layer further has another retardation layer on the outside of the retardation layer, and the refractive index characteristic of the other retardation layer shows the relationship of nz> nx = ny. The method for manufacturing a polarizing plate with a retardation layer according to the above method. The retardation layer has a laminated structure of an oriented solidified layer of a first liquid crystal compound and an oriented solidified layer of a second liquid crystal compound.
The Re (550) of the oriented solidified layer of the first liquid crystal compound is 200 nm to 300 nm, and the angle formed by the slow axis thereof and the absorption axis of the substituent is 10 ° to 20 °.
The Re (550) of the oriented solidified layer of the second liquid crystal compound is 100 nm to 190 nm, and the angle between the slow axis thereof and the absorption axis of the substituent is 70 ° to 80 °.
The method for manufacturing a polarizing plate with a retardation layer according to any one of claims 1 to 11. The method for manufacturing a polarizing plate with a retardation layer according to any one of claims 1 to 14, wherein the total thickness of the polarizing plate with a retardation layer is 45 μm or less.

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