Method for manufacturing polarizing plate with phase difference layer

Abstract

The present application provides a polarizing plate with a phase difference layer having a good yield and suppressed warping. The manufacturing method of the polarizing plate with a phase difference layer according to the present application includes: preparing a laminate having a first protective film, a polarizing plate including a polarizer and a protective layer disposed on at least one side of the polarizer, a phase difference layer, and a second protective film in this order, wherein the sum of the thickness of the polarizing plate and the thickness of the phase difference layer is 50 μm or less, and the ratio of the thickness of the polarizing plate to the thickness of the phase difference layer is 5 or more; and placing the laminate in a state where the laminate is placed on a placement surface with a water vapor amount of 10.5 g / m 3 The humidification treatment is performed in the above environment; wherein the laminate is placed in a state where the main surface of the laminate has an angle with respect to the placement surface.

Description

TECHNICAL FIELD

[0001] The present application relates to a manufacturing method of a polarizing plate with a phase difference layer. BACKGROUND

[0002] Image display devices typified by liquid crystal display devices and electroluminescence (EL) display devices (for example, organic EL display devices, inorganic EL display devices) are rapidly spreading. Polarizing plates and phase difference plates are used in image display devices. A polarizing plate with a phase difference layer in which a polarizing plate and a phase difference plate are integrated is widely used in practical applications (for example, Patent Document 1). In recent years, the possibility of bending, folding, folding, and winding of image display devices using flexible substrates (for example, resin substrates) is being explored. As a polarizing plate with a phase difference layer used in such image display devices, a thin polarizing plate with a phase difference layer is required. However, a thin polarizing plate with a phase difference layer has a problem of being easily warped.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: Japanese Patent No. 3325560 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The present application has been achieved in order to solve the above-described problems of the related art, and a main object thereof is to provide a polarizing plate with a phase difference layer in which warping is suppressed with good yield.

[0008] MEANS FOR SOLVING THE PROBLEMS

[0009] According to an embodiment of the present application, a manufacturing method of a polarizing plate with a phase difference layer is provided. The manufacturing method includes:

[0010] preparing a laminate having, in order, a first protective film, a polarizing plate including a polarizer and a protective layer disposed on at least one side of the polarizer, a phase difference layer, and a second protective film, the sum of the thickness of the polarizing plate and the thickness of the phase difference layer being 50 μm or less, and the ratio of the thickness of the polarizing plate to the thickness of the phase difference layer being 5 or more; and

[0011] placing the laminate on a placement surface in a state in which the laminate is placed on the placement surface with the laminate having an angle with respect to the placement surface, and 3 the humidification treatment is performed in the above-described environment,

[0012] the placing is performed in a state in which the main surface of the laminate has an angle with respect to the placement surface.

[0013] In one embodiment, the manufacturing method includes laminating the polarizing plate and the phase difference layer to obtain a laminate precursor.

[0014] In one embodiment, the manufacturing method includes cutting the laminate precursor into a single sheet.

[0015] In one embodiment, the humidification treatment is performed in a state where a plurality of the laminates are arranged.

[0016] In one embodiment, the moisture permeability of the first protective film at 40°C and 92% RH is 30 g / m 2 or less.

[0017] In one embodiment, the moisture permeability of the second protective film at 40°C and 92% RH is 30 g / m 2 or less.

[0018] In one embodiment, the manufacturing method includes laminating the polarizing plate and the phase difference layer while roll-transporting the polarizing plate and the phase difference layer.

[0019] In one embodiment, the manufacturing method includes laminating the polarizing plate and the phase difference layer using a reactive energy ray-curable adhesive.

[0020] In one embodiment, the thickness of the cured reactive energy ray-curable adhesive is 0.4 μm or more.

[0021] In one embodiment, the laminate has an adhesive layer disposed on the side of the phase difference layer on which the polarizing plate is not disposed, and the weight increase per unit area of the laminated portion of the polarizing plate, the phase difference layer, and the adhesive layer resulting from the humidification treatment is 0.1% or more.

[0022] In one embodiment, the humidification treatment is performed for 6 hours or more.

[0023] In one embodiment, the amount of water vapor during the humidification treatment is 10.5 g / m 3 to 30 g / m 3 .

[0024] In one embodiment, the manufacturing method includes laminating the polarizing plate and the phase difference layer in an environment where the amount of water vapor is 10.2 g / m 3 or more.

[0025] In one embodiment, the amount of water vapor during the humidification treatment is 0.5 g / m 3 or more than the amount of water vapor during the lamination of the polarizing plate and the phase difference layer.

[0026] In one embodiment, the moisture permeability of the phase difference layer or the protective layer at 40°C and 92% RH is 300 g / m 2 • 24 hours or more.

[0027] In one embodiment, in the polarizing plate described above, a protective layer is provided only on the side of the polarizer on which the phase difference layer is not provided.

[0028] In one embodiment, the center of gravity in the thickness direction of the polarizer is closer to the phase difference layer side than the center of gravity in the thickness direction of the laminated portion of the polarizing plate and the phase difference layer.

[0029] In one embodiment, the phase difference layer is an oriented and cured layer of a liquid crystal compound.

[0030] Effects of the Invention

[0031] According to the embodiment of the present application, by performing a moisture treatment on a laminate sequentially having a first protective film, a polarizing plate, a phase difference layer, and a second protective film under prescribed conditions, even if the polarizing plate and the phase difference layer have prescribed thicknesses, a polarizing plate with a phase difference layer that has been suppressed from warping can be manufactured with good yield. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a schematic cross-sectional view showing the general configuration of a laminate of the first embodiment of the present application.

[0033] Figure 2 is a schematic cross-sectional view showing the general configuration of a laminate of the second embodiment of the present application.

[0034] Figure 3 is a cross-sectional view showing one example of the state of warping of a laminate precursor.

[0035] Figure 4 is a cross-sectional view showing one example of a laminated portion from a polarizing plate to an adhesive layer.

[0036] Figure 5 is a cross-sectional view showing one example of the state of placing a laminate on a placement surface. DETAILED DESCRIPTION

[0037] Hereinafter, embodiments of the present application will be described, but the present application is not limited to these embodiments.

[0038] (Definitions of Terms and Symbols)

[0039] The definitions of terms and symbols in this specification are as follows.

[0040] (1) Refractive Indexes (nx, ny, nz)

[0041] "nx" is the refractive index in the direction in which the in-plane refractive index becomes the largest (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.

[0042] (2) In-Plane Phase Difference (Re)

[0043] "Re(λ)" is the in-plane phase difference measured using light having a wavelength of λ nm at 23°C. For example, "Re(550)" is the in-plane phase difference measured using light having a wavelength of 550 nm at 23°C. Re(λ) is obtained using the formula: Re(λ) = (nx - ny) x d, when the thickness of the layer (film) is set to d (nm).

[0044] (3) Thickness Direction Phase Difference (Rth)

[0045] "Rth(λ)" is the thickness direction phase difference measured using light having a wavelength of λ nm at 23°C. For example, "Rth(550)" is the thickness direction phase difference measured using light having a wavelength of 550 nm at 23°C. Rth(λ) is obtained using the formula: Rth(λ) = (nx - nz) x d, when the thickness of the layer (film) is set to d (nm).

[0046] (4) Nz Coefficient

[0047] The Nz coefficient is obtained using Nz = Rth / Re.

[0048] (5) Angle

[0049] When an angle is mentioned in the present specification, the angle includes both the clockwise angle and the counterclockwise angle with respect to a reference direction. Thus, for example, "45°" means ±45°.

[0050] The manufacturing method of a polarizing plate with a phase difference layer of one embodiment of the present application includes: preparing a laminate having a polarizing plate including a polarizer and a phase difference layer; and placing the laminate in a prescribed environment in a state where the laminate is placed on a placement surface.

[0051] A. Laminate

[0052] Figure 1A schematic cross-sectional view showing the general configuration of the laminate of the first embodiment of the present application. The laminate 100 has, in order from the visible side, a first protective film 31, a polarizing plate 10, a phase difference layer 20, and a second protective film 32. In the illustrated example, the polarizing plate 10 includes a polarizer 11 and a protective layer 12 disposed on the visible side of the polarizer 11 (the side on which the phase difference layer 20 is not disposed), and no protective layer is disposed between the polarizer 11 and the phase difference layer 20. According to this manner, the thickness of the polarizing plate, the total thickness, and the thickness ratio described later can be favorably achieved. Typically, the center of gravity in the thickness direction of the polarizer is closer to the phase difference layer side than the center of gravity in the thickness direction of the laminated portion of the polarizing plate and the phase difference layer.

[0053] Although not illustrated, a protective layer can be further included on the other side of the polarizer 11 (between the polarizer 11 and the phase difference layer 20).

[0054] Figure 2 A schematic cross-sectional view showing the general configuration of the laminate of the second embodiment of the present application. In the first embodiment described above, the phase difference layer 20 is a single layer, whereas in the second embodiment, the phase difference layer 20 has a laminated structure including a first phase difference layer 21 and a second phase difference layer 22. The phase difference layer 20 can have a laminated structure of three or more layers, which can be different from the illustrated example.

[0055] Although not illustrated, the laminate can further have other functional layers. The kind, properties, number, combination, and arrangement of the functional layers that the laminate can have can be appropriately set according to the purpose. For example, the laminate can further have a conductive layer or an isotropic substrate with a conductive layer. The conductive layer or the isotropic substrate with a conductive layer is typically disposed between the phase difference layer 20 and the second protective film 32. Further, the laminate having a conductive layer or an isotropic substrate with a conductive layer (a polarizing plate with a phase difference layer) can be applied, for example, to a so-called in-cell touch panel input display device in which a touch sensor is incorporated inside an image display panel. As another example, the laminate can further have another phase difference layer. The optical properties (e.g., refractive index properties, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, and arrangement of the other phase difference layer can be appropriately set according to the purpose. As a specific example, another phase difference layer (typically, a layer that imparts a (elliptical) polarized light function, a layer that imparts an ultra-high retardation) that improves visibility when viewed through a polarizing lens such as a polarized sunglasses can be provided on the visible side of the polarizer 11. By having such a layer, excellent visibility can be achieved even when a display screen is viewed through a polarizing lens such as a polarized sunglasses. Thus, the resulting polarizing plate with a phase difference layer can be preferably applied to an image display device that can be used outdoors.

[0056] The components constituting the laminate can be laminated via any suitable adhesive layer (not shown). Specific examples of adhesive layers include adhesive layers and bonding agents. For example, the first protective film 31 is adhered to the polarizer 10 via an adhesive layer. The first protective film 31 can be peeled off before the polarizer with a phase retardation layer obtained by the embodiments of the present invention is supplied for use (until it is laminated to the image display panel) or during the manufacturing process of the final product (image display device), or it can be directly mounted on the final product.

[0057] For example, the second protective film 32 is adhered to the phase retardation layer 20 via an adhesive layer. In practical applications, the second protective film 32 can function as a release film (septum) temporarily attached before supplying a polarizer with a phase retardation layer obtained through embodiments of the present invention to its intended use. By temporarily attaching the release film, for example, the roll formation of the laminate can be performed while protecting the adhesive layer.

[0058] For example, the phase retardation layer 20 is bonded to the polarizer 10 via an adhesive layer (preferably using an active energy line curing adhesive). When the phase retardation layer 20 has a stacked structure of two or more layers, each phase retardation layer is bonded via an adhesive layer (preferably using an active energy line curing adhesive).

[0059] A-1. Polarizing filter

[0060] The aforementioned polarizer includes a polarizer and a protective layer. While the thickness of the polarizer also depends on the number of protective layers, it is preferably 20 μm or more, more preferably 25 μm or more. On the other hand, the thickness of the polarizer is preferably 40 μm or less, more preferably 36 μm or less, and even more preferably 33 μm or less. Furthermore, when an adhesive layer is used when stacking the polarizer and the protective layer, the thickness of the polarizer does not include the thickness of that adhesive layer.

[0061] The aforementioned polarizer is typically a resin membrane containing a dichroic substance (e.g., iodine). Examples of resin membranes include hydrophilic polymer membranes such as polyvinyl alcohol (PVA) membranes, partially formalized PVA membranes, and partially saponified ethylene-vinyl acetate copolymer membranes.

[0062] The thickness of the polarizer is preferably 15 μm or less, more preferably 12 μm or less, and even more preferably 10 μm or less. On the other hand, the thickness of the polarizer is preferably 1 μm or more.

[0063] The polarizer preferably exhibits absorption dichroism at any wavelength from 380 nm to 780 nm. The transmittance of the polarizer is, for example, 41.5% to 46.0%, preferably 42.0% to 46.0%, more preferably 44.5% to 46.0%. The polarization degree of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and even more preferably 99.9% or more.

[0064] The protective layer described above can be formed of any appropriate film that can be used as a protective layer for a polarizer. As specific examples of materials that are main components of the film, cellulose-based resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, polysulfone-based, polystyrene-based, polynorbornene-based, and the like, transparent resins such as cyclic olefin-based, polyolefin-based, (meth)acrylic-based, and acetate-based resins can be given.

[0065] The polarizing plate with a phase difference layer obtained by the embodiment of the present application is typically disposed on the viewable side of an image display device, and the protective layer 12 is disposed on the viewable side. Therefore, surface treatment such as hard coat (HC) treatment, anti-reflection treatment, anti-blocking treatment, anti-glare treatment, and the like can also be performed on the protective layer 12 as needed.

[0066] The thickness of the protective layer 12 is preferably 5 μm to 80 μm, more preferably 10 μm to 40 μm, and further preferably 10 μm to 30 μm. In addition, when the surface treatment described above is performed, the thickness of the protective layer 12 is the thickness including the thickness of the surface treatment layer.

[0067] The protective layer (not shown) disposed between the polarizer 11 and the phase difference layer 20 is preferably optically isotropic in one embodiment. "Optically isotropic" in the present specification means that the in-plane retardation Re(550) is 0 nm to 10 nm, and the thickness direction retardation Rth(550) is -10 nm to +10 nm. The thickness of the protective layer disposed between the polarizer 11 and the phase difference layer 20 is preferably 5 μm to 80 μm, more preferably 10 μm to 40 μm, and further preferably 10 μm to 30 μm.

[0068] The polarizing plate can be produced by any appropriate method. Specifically, the polarizing plate can include a polarizer produced from a single layer of a resin film, and can also include a polarizer obtained using a laminate of two or more layers.

[0069] The method of producing a polarizer from a single layer of a resin film typically includes performing dyeing treatment using a dichroic substance such as iodine or a dichroic dye, and stretching treatment on the resin film. As the resin film, for example, a hydrophilic polymer film such as a polyvinyl alcohol (PVA)-based film, a partially formalized PVA-based film, an ethylene-vinyl acetate copolymer-based partially saponified film, and the like is used. The method can further include insolubilization treatment, swelling treatment, cross-linking treatment, and the like. By laminating a protective layer on at least one side of the obtained polarizer, a polarizing plate can be obtained. Since this production method is conventionally known in the technical field, detailed description is omitted.

[0070] As a specific example of the polarizer obtained using the above-described laminate, a polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate or a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate can be given. The polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate can be produced, for example, by coating a PVA-based resin solution on a resin substrate, drying it to form a PVA-based resin layer on the resin substrate, thereby obtaining a laminate of a resin substrate and a PVA-based resin layer, and stretching and dyeing the above-described laminate to produce a PVA-based resin layer as a polarizer. In the present embodiment, it is preferable that a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin be formed on one side of the resin substrate. The stretching typically includes stretching by immersing the laminate in an aqueous boric acid solution. Further, the stretching can further include, as necessary, aerial stretching of the laminate at a high temperature (e.g., 95°C or higher) before stretching in an aqueous boric acid solution. Further, in the present embodiment, it is preferable that the laminate be supplied to a drying shrinkage treatment in which the laminate is transported in the longitudinal direction while being heated to shrink by 2% or more in the width direction. Typically, the production method of the present embodiment includes sequentially performing an aerial auxiliary stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment on the laminate. By introducing the auxiliary stretching, even when the PVA is coated on the thermoplastic resin, the crystallinity of the PVA can be improved, and high optical properties can be achieved. In addition, by simultaneously improving the orientation of the PVA in advance, it is possible to prevent problems such as a decrease in the orientation of the PVA or dissolution of the PVA when immersed in water in the subsequent dyeing step or stretching step, and high optical properties can be achieved. Further, when the PVA-based resin layer is immersed in a liquid, compared to when the PVA-based resin layer does not contain a halide, it is possible to suppress the orientation disorder of polyvinyl alcohol molecules and a decrease in the orientation. Thus, it is possible to improve the optical properties of the polarizer obtained by immersing the laminate in a liquid in the treatment steps such as the dyeing treatment and the underwater stretching treatment. Further, by shrinking the laminate in the width direction using the drying shrinkage treatment, it is possible to improve the optical properties. The obtained laminate of a resin substrate / polarizer can be used as it is (i.e., the resin substrate can be used as a protective layer for the polarizer), or the resin substrate can be peeled from the laminate of a resin substrate / polarizer, and the obtained peeled surface or the surface on the side opposite to the obtained peeled surface can be used after laminating an arbitrary appropriate protective layer corresponding to the intended purpose. Details of such a production method of a polarizer are described, for example, in Japanese Patent Application Publication No. 2012-73580 and Japanese Patent No. 6470455. These publications are incorporated by reference in their entireties in the present specification.

[0071] A-2. Phase difference layer

[0072] The thickness of the above-mentioned phase difference layer, although depending on its constitution (single layer or stacked structure), is preferably 8 μm or less, more preferably 5 μm or less. On the other hand, the thickness of the phase difference layer is, for example, 1 μm or more. Further, when the phase difference layer is of a stacked structure, the "thickness of the phase difference layer" means the sum of the thicknesses of the respective phase difference layers. Specifically, the thickness of the phase difference layer does not include the thickness of the adhesive layer.

[0073] As the above-mentioned phase difference layer, an oriented and cured layer of a liquid crystal compound (liquid crystal oriented and cured layer) is preferably used. By using a liquid crystal compound, the difference between nxand nyof the resulting phase difference layer can be made particularly large as compared with a non-liquid crystal material, and thus the thickness of the phase difference layer for obtaining a desired in-plane phase difference can be made particularly small. Therefore, a polarizing plate with a phase difference layer can be made remarkably thin. In the present specification, the "oriented and cured layer" means a layer in which a liquid crystal compound is oriented in a prescribed direction within the layer and the oriented state thereof is fixed. Further, the "oriented and cured layer" is a concept including an oriented and cured layer obtained by curing a liquid crystal monomer as described later. In the phase difference layer, typically, a rod-like liquid crystal compound is oriented in a state of being aligned in the slow axis direction of the phase difference layer (homeotropic orientation).

[0074] The above-mentioned liquid crystal oriented and cured layer is obtained by subjecting the surface of a prescribed substrate to orientation treatment, applying a coating liquid containing a liquid crystal compound to the surface, orienting the liquid crystal compound in a direction corresponding to the above-mentioned orientation treatment, and fixing the oriented state. As the orientation treatment, any appropriate orientation treatment can be employed. Specifically, mechanical orientation treatment, physical orientation treatment, and chemical orientation treatment can be mentioned. As specific examples of the mechanical orientation treatment, rubbing treatment and stretching treatment can be mentioned. As specific examples of the physical orientation treatment, magnetic field orientation treatment and electric field orientation treatment can be mentioned. As specific examples of the chemical orientation treatment, oblique evaporation method and photo-orientation treatment can be mentioned. The treatment conditions of the various orientation treatments can be appropriately selected according to the purpose.

[0075] The orientation of the liquid crystal compound is carried out by subjecting the liquid crystal compound to a treatment at a temperature at which the liquid crystal phase appears depending on the kind of the liquid crystal compound. By carrying out such a temperature treatment, the liquid crystal compound becomes in a liquid crystal state, and is oriented depending on the orientation treatment direction of the surface of the substrate.

[0076] The fixation of the oriented state is carried out in one embodiment by cooling the liquid crystal compound oriented as above. When the liquid crystal compound is a polymerizable monomer or a cross-linkable monomer, the fixation of the oriented state is carried out by subjecting the liquid crystal compound oriented as above to a polymerization treatment or a cross-linking treatment.

[0077] Detailed description of specific examples of the liquid crystal compound and the method of forming the alignment-cured layer is described in Japanese Patent Application Publication No. 2006-163343. The description of the publication is incorporated herein by reference in its entirety.

[0078] The phase difference layer 20 can be a single layer as described above, and can also have a laminated structure of two or more layers.

[0079] As Figure 1 In one embodiment where the phase difference layer 20 is a single layer, the phase difference layer 20 can function as a λ / 4 plate. Specifically, the Re(550) of the phase difference 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 phase difference layer can be adjusted in a manner to obtain a desired in-plane phase difference of a λ / 4 plate. When the phase difference layer is the liquid crystal alignment-cured layer described above, the thickness thereof is, for example, 1.0 μm to 2.5 μm. In the present embodiment, the angle formed by the slow axis of the phase difference layer and the absorption axis of the polarizer is preferably 40° to 50°, more preferably 42° to 48°, and further preferably 44° to 46°. In the present embodiment, the phase difference layer preferably exhibits a reverse dispersion wavelength characteristic in which the phase difference value increases as the wavelength of the measuring light increases. In addition, in the present embodiment, the laminated body can further have a layer (another phase difference layer, not shown) having a refractive index characteristic of exhibiting nz> nx= ny disposed between the phase difference layer 20 and the second protective film 32.

[0080] In another embodiment where the phase difference layer 20 is a single layer, the phase difference layer 20 can function as a λ / 2 plate. Specifically, the Re(550) of the phase difference layer is preferably 200 nm to 300 nm, more preferably 230 nm to 290 nm, and further preferably 230 nm to 280 nm. The thickness of the phase difference layer can be adjusted in a manner to obtain a desired in-plane phase difference of a λ / 2 plate. When the phase difference layer is the liquid crystal alignment-cured layer described above, the thickness thereof is, for example, 2.0 μm to 4.0 μm. In the present embodiment, the angle formed by the slow axis of the phase difference layer and the absorption axis of the polarizer is preferably 10° to 20°, more preferably 12° to 18°, and further preferably 12° to 16°.

[0081] As Figure 2When the phase difference layer 20 has a stacked structure, the phase difference layer 20 has, for example, a two-layer stacked structure in which a first phase difference layer (H layer) 21 and a second phase difference layer (Q layer) 22 are disposed in this order from the polarizing plate side. The H layer typically functions as a λ / 2 plate, and the Q layer typically functions as a λ / 4 plate. Specifically, the Re(550) of the H layer is preferably 200 nm to 300 nm, more preferably 220 nm to 290 nm, and further preferably 230 nm to 280 nm; and the Re(550) of the Q layer is preferably 100 nm to 180 nm, more preferably 110 nm to 170 nm, and further preferably 110 nm to 150 nm. The thickness of the H layer can be adjusted in a manner to obtain a desired in-plane retardation of a λ / 2 plate. When the H layer is the above-described liquid crystal alignment cured layer, the thickness thereof is, for example, 2.0 μm to 4.0 μm. The thickness of the Q layer can be adjusted in a manner to obtain a desired in-plane retardation of a λ / 4 plate. When the Q layer is the above-described liquid crystal alignment cured layer, the thickness thereof is, 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 polarizer is preferably 10° to 20°, more preferably 12° to 18°, and further preferably 12° to 16°; and the angle formed by the slow axis of the Q layer and the absorption axis of the polarizer is preferably 70° to 80°, more preferably 72° to 78°, and further preferably 72° to 76°. When the phase difference layer 20 has a stacked structure, each layer (e.g., the H layer and the Q layer) can exhibit a reverse dispersion wavelength characteristic in which the phase difference value increases in correspondence with the wavelength of the measuring light, can exhibit a positive wavelength dispersion characteristic in which the phase difference value decreases in correspondence with the wavelength of the measuring light, or can exhibit a flat wavelength dispersion characteristic in which the phase difference value does not substantially change in correspondence with the wavelength of the measuring light.

[0082] The phase difference layer 20 (each layer when having a stacked structure) typically exhibits a refractive index characteristic showing a relationship of nx>ny=nz. Here, "ny=nz" includes not only a case where ny and nz are completely equal, but also a case where they are substantially equal. Therefore, there are cases where ny>nz or ny<nz, without impairing the effects of the present application. The Nz coefficient of the phase difference layer is preferably 0.9 to 1.5, and more preferably 0.9 to 1.3.

[0083] As described above, the phase difference layer is preferably a liquid crystal alignment cured layer. As the above-described liquid crystal compound, for example, a liquid crystal compound having a nematic phase (nematic liquid crystal) can be given. As such a liquid crystal compound, for example, a liquid crystal polymer or a liquid crystal monomer can be used. The mechanism of exhibiting the liquid crystallinity of the liquid crystal compound can be either one of lyotropic and thermotropic. The liquid crystal polymer and the liquid crystal monomer can be used individually, or can be combined.

[0084] When the liquid crystal compound is a liquid crystal monomer, the liquid crystal monomer is preferably a polymerizable monomer and a crosslinkable monomer. The reason for this is that by polymerizing or crosslinking (i.e., curing) the liquid crystal monomer, the alignment state of the liquid crystal monomer can be fixed. After the liquid crystal monomer is aligned, if the liquid crystal monomers are polymerized or crosslinked with each other, for example, the above-mentioned alignment state can be fixed thereby. Here, a polymer is formed by polymerization and a three-dimensional network structure is formed by crosslinking, but they are non-liquid crystalline. Therefore, the phase difference layer formed does not undergo a transition to a liquid crystal phase, a glass phase, or a crystalline phase due to a change in temperature, for example, which is characteristic of a liquid crystalline compound. As a result, the phase difference layer becomes a phase difference layer that is extremely excellent in stability against a change in temperature.

[0085] The temperature range in which the liquid crystal monomer exhibits liquid crystallinity varies depending on the kind thereof. Specifically, the temperature range is preferably 40°C to 120°C, further preferably 50°C to 100°C, and most preferably 60°C to 90°C.

[0086] As the above-mentioned liquid crystal monomer, any appropriate liquid crystal monomer can be used. For example, a polymerizable mesogenic compound described in Japanese Kokai 2002-533742 (WO 00 / 37585), EP 358208 (US 5211877), EP 66137 (US 4388453), WO 93 / 22397, EP 0261712, DE 19504224, DE 4408171, and GB 2280445, and the like can be used. As specific examples of such a polymerizable mesogenic compound, for example, the trade name LC242 of BASF Co., the trade name E7 of Merck Co., and the trade name LC-Sillicon-CC 3767 of Wacker-Chem Co. can be given. As the liquid crystal monomer, a nematic liquid crystal monomer is preferred.

[0087] A-3. Relationship between the thickness of the polarizing plate and the thickness of the phase difference layer

[0088] The sum of the thickness of the above-mentioned polarizing plate and the thickness of the above-mentioned phase difference layer (sometimes referred to simply as "total thickness") is 50 μm or less, preferably 45 μm or less, and more preferably 40 μm or less. On the other hand, the total thickness is, for example, 25 μm or more.

[0089] The ratio of the thickness of the above-mentioned polarizing plate to the thickness of the above-mentioned phase difference layer (thickness of the polarizing plate / thickness of the phase difference layer, sometimes referred to simply as "thickness ratio") is 5 or more, preferably 8 or more, and more preferably 10 or more. On the other hand, the thickness ratio is preferably 30 or less, and more preferably 25 or less.

[0090] The laminate used in the manufacturing method of the embodiment of the present application can be said to be thin in total thickness and large in the proportion of the thickness of the polarizing plate to the total thickness (small in the proportion of the thickness of the phase difference layer). The present inventors and others have found that the problem of warping described above tends to occur when the total thickness and the thickness ratio are within the above-described prescribed ranges. More specifically, when the difference between the thickness of the polarizing plate and the thickness of the phase difference layer is not large and when the thickness of the polarizing plate is too large, warping tends not to occur in the polarizing plate with the phase difference layer. The present inventors and others have conducted intensive research on the suppression of warping based on this new finding, and as a result, have found that warping can be efficiently suppressed by the manufacturing method of the embodiment of the present application.

[0091] A-4. First protective film

[0092] The first protective film 31 can be formed using any appropriate material. As specific examples of the material, polyester-based polymers such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), cellulose-based polymers such as cellulose diacetate and cellulose triacetate, polycarbonate-based polymers, (meth)acrylic-based polymers such as polymethyl methacrylate, and cyclic olefin-based polymers such as polynorbornene can be given. These materials can be used alone or in combination with two or more.

[0093] The first protective film preferably has a moisture permeability of 30 g / m 2 • 24 h or less, more preferably 20 g / m 2 • 24 h or less. According to this first protective film, moisture can be appropriately imparted to the laminate (preferably the polarizer) in the humidification treatment described later, and a polarizing plate with a phase difference layer in which warping is suppressed can be obtained. On the other hand, the first protective film has a moisture permeability of, for example, 5 g / m 2 • 24 h or more.

[0094] The thickness of the first protective film is preferably 15 μm to 50 μm, more preferably 25 μm to 40 μm.

[0095] As described above, the first protective film 31 can be attached to the polarizing plate 10 via an adhesive layer. As the adhesive layer, any appropriate configuration can be employed. As specific examples, an acrylic adhesive, a rubber-based adhesive, a silicone-based adhesive, a polyester-based adhesive, a urethane-based adhesive, an epoxy-based adhesive, and a polyether-based adhesive can be given. By adjusting the kind, amount, combination, and ratio of monomers of the base resin forming the adhesive, the amount of cross-linking agent, the reaction temperature, the reaction time, and the like, an adhesive having desired properties corresponding to the purpose can be prepared. The base resin of the adhesive can be used alone, and two or more kinds can be used in combination. The base resin is preferably an acrylic resin (specifically, the adhesive layer is preferably composed of an acrylic adhesive). The thickness of the adhesive layer is, for example, 5 to 15 μm. The storage elastic modulus of the adhesive layer at 25°C is, for example, 1.0 x 10 5 Pa to 1.0 x 10 7 Pa.

[0096] In one embodiment, a laminate in which the above-described adhesive layer is formed in advance on the first protective film (hereinafter referred to as "surface protective film") is used. The thickness of the surface protective film is preferably 30 to 60 μm, more preferably 30 to 50 μm. Further, as described above, when the first protective film is peeled, it can be peeled together with the adhesive layer (together with the surface protective film).

[0097] A-5. Second Protective Film

[0098] The second protective film 32 can be composed of any appropriate plastic film. As specific examples of the plastic film, a polyethylene terephthalate (PET) film, a polyethylene film, and a polypropylene film can be given. As described above, the second protective film 32 can function as a separator. Specifically, as the second protective film 32, a plastic film on the surface of which a peeling agent is applied is preferably used. As specific examples of the peeling agent, a silicone-based peeling agent, a fluorine-based peeling agent, and an acrylic long-chain alkyl ester-based peeling agent can be given.

[0099] The second protective film preferably has a moisture permeability of 30 g / m 2 or less, more preferably 20 g / m 2 or less, at 40°C and 92% RH. According to such a second protective film, in the humidity treatment described later, moisture can be appropriately imparted to the laminate (preferably, the polarizer), and a polarizing plate with a phase difference layer in which warping is suppressed can be obtained. On the other hand, the second protective film has a moisture permeability of, for example, 5 g / m 2 or more, at 40°C and 92% RH.

[0100] The thickness of the second protective film is preferably 20 to 80 μm, more preferably 35 to 55 μm.

[0101] A-6. Construction of Layered Bodies

[0102] The laminate 100 can be obtained, for example, by laminating a polarizer 10 and a phase difference layer 20 to create a laminate precursor, and then laminating a first protective film 31 and a second protective film 32 on the resulting laminate precursor.

[0103] The polarizer 10 and the phase retardation layer 20 are stacked, for example, while they are being rolled (by means of so-called roll-to-roll). The stacking is typically performed by transferring a liquid crystal alignment and curing layer formed on a substrate. Figure 2 As shown, when the phase difference layer has a stacked structure, each phase difference layer can be stacked (transferred) onto the polarizer in sequence, or the stack of phase difference layers can be stacked (transferred) onto the polarizer.

[0104] The above-mentioned transfer is performed, for example, using an active energy line curable adhesive. The cured thickness of the active energy line curable adhesive (the thickness of the adhesive layer) is preferably 0.4 μm or more, more preferably 0.4 μm to 3.0 μm, and even more preferably 0.6 μm to 1.5 μm. The warping of the polarizer with the phase retardation layer having the above-specified total thickness and thickness ratio is mainly caused by the adhesive used in the lamination of the polarizer and the phase retardation layer (specifically, the shrinkage of the active energy line curable adhesive during curing), which causes warping in the laminate precursor obtained by laminating the polarizer 10 and the phase retardation layer 20.

[0105] Figure 3 A cross-sectional view illustrating one example of the warped state of a laminate precursor. Furthermore, Figure 3 In order to facilitate observation of the attached drawings, the cross-sectional lines of the laminated body precursor have been omitted. Figure 3 In the example shown, the laminate precursor 90 exhibits a convex warp on the polarizer 10 side. The warp tends to occur along the absorption axis of the polarizer 10 (polarizer 11).

[0106] The polarizer 10 and the phase retardation layer 20 are preferably stacked when the water vapor content (A1) is 10.2 g / m. 3 The following conditions shall be met. The water vapor content (A1) in the stack is more preferably 6.0 g / m³. 3 ~10.0g / m 3 Further preferred is 8.0 g / m 3 ~9.5g / m 3By performing the lamination in an environment in which the amount of water vapor (Al) is in such a range, the effect produced by the humidification treatment described later becomes significant. Such an amount of water vapor (Al) in the lamination can be achieved, for example, by changing the relative humidity in correspondence with the temperature in the range of 18°C to 25°C. The amount of water vapor (Al) can be achieved, for example, by making the relative humidity 65% RH or less at a temperature of 18°C, by making the relative humidity 55% RH or less at a temperature of 20°C, and by making the relative humidity 45% RH or less at a temperature of 23°C. Further, the lower limit of the relative humidity can be, for example, 30% RH.

[0107] In one embodiment, the moisture permeability of either of the protective layer 12 and the phase difference layer 20 at 40°C and 92% RH is preferably 300 g / m 2 • 24 h or more, more preferably 400 g / m 2 • 24 h to 1000 g / m 2 • 24 h, further preferably 400 g / m 2 • 24 h to 800 g / m 2 • 24 h. When either of the protective layer 12 and the phase difference layer 20 is such a moisture permeability, the effect produced by the humidification treatment described later can become significant.

[0108] As described above, when the laminate further has other functional layers (e.g., a conductive layer, another phase difference layer), the functional layers can be laminated or formed at the prescribed positions using any appropriate method.

[0109] The lamination of the laminate precursor having at least the polarizing plate 10 and the phase difference layer 20 and the first protective film 31 is performed, for example, by adhering the above-described surface protective film. The lamination of the laminate precursor and the second protective film 32 is performed, for example, using an adhesive. The thickness of the adhesive (the thickness of the adhesive layer disposed between the phase difference layer 20 and the second protective film 32) is, for example, 10 μm to 20 μm.

[0110] B. Humidification Treatment

[0111] The above-described laminate is supplied to the humidification treatment. By subjecting the laminate to the humidification treatment, moisture can be imparted to the laminate (preferably, the polarizer), and a phase difference layer-equipped polarizing plate in which warping is suppressed can be obtained. For example, by placing the laminate in an environment in which the amount of water vapor is 10.5 g / m 3 The humidification treatment is performed in the above-described environment. The amount of water vapor (A2) at the time of the humidification treatment is preferably 10.5 g / m 3 to 30 g / m 3 , more preferably 11 g / m 3 to 20 g / m 3 .

[0112] The water vapor amount (A2) at the time of the above humidification treatment can be achieved, for example, by making the relative humidity 80% RH or more at a temperature of 18°C; or, for example, by making the relative humidity 60% RH or more at a temperature of 20°C; or, for example, by making the relative humidity 50% RH or more at a temperature of 23°C. Further, the upper limit of the relative humidity can be, for example, 100% RH.

[0113] In one embodiment, the humidification treatment is performed on the laminate in an environment in which the water vapor amount is more than the above water vapor amount (Al). More specifically, the difference between the water vapor amount (A2) at the time of the humidification treatment and the above water vapor amount (Al) is preferably 0.5 g / m 3 More preferably, it is 1.0 g / m 3 ~ 28 g / m 3 Further preferably, it is 1.0 g / m 3 ~ 12 g / m 3 Particularly preferably, it is 1.5 g / m 3 ~ 10 g / m 3 Most preferably, it is 1.5 g / m 3 ~ 8 g / m 3 By performing the humidification under such conditions, an appropriate amount of moisture can be imparted to the laminate. More specifically, moisture can be imparted to the laminate without causing shrinkage of the laminate. When the amount of moisture imparted to the laminate is too large in the humidification treatment, the following can occur, for example, warping in a direction opposite to the initial warping convexity and / or warping in a direction orthogonal to the initial warping direction in the plane.

[0114] In one embodiment, it is preferable that the humidification treatment be performed on the laminate in such a manner that the weight per unit area of the laminated portion from the polarizing plate to the adhesive layer is increased by 0.1% or more. The increase in the weight per unit area of the laminated portion from the polarizing plate to the adhesive layer resulting from the humidification treatment is more preferably 0.1% to 2.0%, further preferably 0.1% to 1.0%, and particularly preferably 0.1% to 0.5%. By increasing the weight to such a range, the polarizer can absorb a desired amount of moisture. As a result, warping of the obtained polarizing plate with a phase difference layer can be effectively suppressed. Here, the laminated portion from the polarizing plate to the adhesive layer refers to the laminated portion 80 of the polarizing plate 10, the adhesive layer 40, the phase difference layer 20 (including the adhesive layer when having a laminated structure), and the adhesive layer 50, as shown in FIG. 8, for example. Figure 4 Figure 4 In FIG. 8, the cross section of the laminated portion is omitted.

[0115] ​The humidification treatment time is preferably 6 hours or more, more preferably 12 hours or more, and even more preferably 24 hours or more. With this treatment time, the desired weight gain (moisture absorption) can be achieved well, for example. On the other hand, the humidification treatment time is, for example, 150 hours or less. Even if the humidification treatment time is too long, the effect will not change; therefore, the upper limit of the humidification treatment time can be determined by balancing the desired weight gain with manufacturing efficiency.

[0116] During the humidification process, the aforementioned laminate is placed with its main surface at an angle relative to the mounting surface. Figure 5 This is a cross-sectional view illustrating one example of a laminated body placed on a mounting surface. Furthermore, Figure 5 In the accompanying drawings, the cross-sectional lines of the laminate are omitted for ease of observation. In the example shown, the laminate 100 is placed on the mounting surface S with its main surface 100a at an angle θ relative to the mounting surface S. The angle θ is greater than 0° and less than 90°, preferably 70° to 90°, and more preferably 80° to 90°.

[0117] Additionally, in the example shown, n sheet-like laminates 100 are arranged with the main surfaces of adjacent laminates 100 overlapping. Typically, the laminates are processed into sheet-like pieces of a specified size before humidification. The sheet-like laminates are preferably obtained by cutting a strip-shaped laminate precursor. Specifically, it is preferable to obtain a sheet-like laminate precursor by cutting the strip-shaped laminate precursor, and then laminating a first protective film and a second protective film onto the sheet-like laminate precursor to obtain the sheet-like laminate. According to this method, for example, large-scale roll-to-roll conveying equipment is not required, thus improving manufacturing efficiency. Furthermore, the cutting is preferably performed according to the condition of the laminate precursor that has warped, such as… Figure 5 The process involves overlapping the monolithic laminates as shown. In one embodiment, the laminations are cut at a 45° angle relative to the length of the elongated laminate precursor. In another embodiment, the laminations are cut along both the length and width directions (orthogonal to the length direction) of the elongated laminate precursor.

[0118] In this way, moisture is efficiently absorbed by the laminate (polarizer), enabling the production of polarizers with suppressed warpage and phase retardation layers with good yield. Specifically, this is achieved by employing a state where the main surface of the laminate is at an angle relative to the mounting surface, such as... Figure 5As shown, the moisture treatment can be performed on a plurality of the laminates at once in a uniform state (e.g., a state in which the force applied to the laminates is uniform). As a result, moisture can be uniformly imparted to the plurality of the laminates (e.g., by the moisture treatment at once, the weight increase of the laminated portion of the polarizing plate and the phase difference layer can be favorably achieved in the plurality of the laminates), and a polarizing plate with a phase difference layer that suppresses warping can be favorably manufactured in yield. In addition, the appearance of the resulting polarizing plate with a phase difference layer is also excellent.

[0119] Example

[0120] Hereinafter, the present application will be specifically described by examples, but the present application is not limited to these examples. In addition, the thickness and the moisture permeability are values measured using the following measurement methods. Furthermore, unless otherwise specified, "parts" and "%" in the examples and comparative examples are weight bases.

[0121] <Thickness>

[0122] The thickness of 10 μm or less was measured using a scanning electron microscope (manufactured by JEOL Ltd., product name "JSM-7100F"). The thickness of more than 10 μm was measured using a digital micrometer (manufactured by Anritsu Corporation, product name "KC-351C").

[0123] <Moisture Permeability>

[0124] The moisture permeability was calculated using a cup method (JIS Z 0208).

[0125] [Example 1]

[0126] (Polarizing Plate Production)

[0127] As the thermoplastic resin substrate, a long strip-shaped, amorphous copolymerized isophthalic acid polyethylene terephthalate film (thickness: 100 μm) having a Tg of about 75°C was used, and a single surface of the resin substrate was subjected to a corona treatment.

[0128] To 100 parts by weight of a PVA-based resin in which polyvinyl alcohol (degree of polymerization: 4200, degree of saponification: 99.2 mol%) and acetyl acetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMER") were mixed at 9: 1, 13 parts by weight of potassium iodide was added, and the mixture was dissolved in water to prepare a PVA aqueous solution (coating solution).

[0129] The above PVA aqueous solution was applied to the corona-treated surface of the resin substrate, and drying was performed at 60°C to form a PVA-based resin layer having a thickness of 13 μm, and a laminate was produced.

[0130] The resulting laminate was uniaxially stretched in the longitudinal direction (lengthwise direction) to 2.4 times in an oven at 130°C (air-assisted stretching treatment).

[0131] Next, the laminate was immersed in a liquid temperature 40°C insolubilization bath (boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with respect to 100 parts by weight of water) for 30 seconds (insolubilization treatment).

[0132] Next, in a liquid temperature 30°C dyeing bath (aqueous iodine solution obtained by mixing iodine and potassium iodide at a weight ratio of 1 :7 with respect to 100 parts by weight of water), the laminate was immersed for 60 seconds (dyeing treatment) while adjusting the concentration in such a manner that the final obtained polarizer monomer transmittance (Ts) became a desired value.

[0133] Next, the laminate was immersed in a liquid temperature 40°C crosslinking bath (aqueous boric acid 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) for 30 seconds (crosslinking treatment).

[0134] Subsequently, the laminate was uniaxially stretched (in-water stretching treatment) between rolls having different circumferential speeds in such a manner that the total stretching ratio in the longitudinal direction (lengthwise direction) reached 5.5 times while being immersed in an aqueous boric acid solution (boric acid concentration: 4% by weight, potassium iodide concentration: 5% by weight) having a liquid temperature of 70°C.

[0135] Subsequently, the laminate was immersed in a liquid temperature 20°C washing bath (aqueous solution obtained by mixing 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) (washing treatment).

[0136] Subsequently, drying was performed in an oven maintained at about 90°C while allowing the contact surface temperature to be maintained at about 75°C using SUS heating rolls (drying shrinkage treatment).

[0137] Thus, a polarizer having a thickness of about 5 μm was formed on the resin substrate, and a laminate having a resin substrate / polarizer configuration was obtained.

[0138] An HC-COP film (thickness: 27 μm) was attached as a protective layer on the polarizer side of the obtained laminate via an ultraviolet-curable adhesive. Further, the HC-COP film is a film in which an HC layer (thickness: 2 μm) is formed on a cyclic olefin resin (COP) film (thickness: 25 μm), and was attached in such a manner that the COP film became the polarizer side. Next, the resin substrate was peeled from the polarizer, and a polarizing plate having an HC-COP film (protective layer) / polarizer configuration was obtained.

[0139] (Production of phase difference layer)

[0140] A liquid crystal composition (coating liquid) was prepared by dissolving 10 g of a polymerizable liquid crystal (manufactured by BASF Corporation; trade name: Paliocolor LC242", represented by the following formula) that exhibits a nematic liquid crystal phase and 3 g of a photopolymerization initiator (manufactured by BASF Corporation; trade name: "Irgacure 907") for the polymerizable liquid crystal compound in 40 g of toluene.

[0141] [Chemical Structural Formula 1]

[0142]

[0143] A polyethylene terephthalate (PET) film (thickness: 38 μm) was rubbed with a rubbing cloth to perform orientation treatment. The orientation treatment direction was a direction that, when the film was attached to a polarizing plate, became 15° from the visual side with respect to the absorption axis direction of a polarizer. The above-described liquid crystal coating liquid was coated on the orientation-treated surface using a bar coater, and heated and dried at 90°C for 2 minutes to orient the liquid crystal compound. The liquid crystal layer thus formed was cured by irradiating the liquid crystal layer with 1 mJ / cm2of light from a metal halide lamp, thereby forming a liquid crystal orientation-cured layer A (H layer) on the PET film. The thickness of the liquid crystal orientation-cured layer A was 2.5 μm, and the in-plane retardation Re(550) was 270 nm. Further, the liquid crystal orientation-cured layer A exhibited a refractive index characteristic of nx>ny=nz. 2

[0144] A liquid crystal orientation-cured layer B (Q layer) was formed on a PET film in the same manner as described above, except that the coating thickness was changed and the orientation treatment direction was changed to a direction that, when the film was attached to a polarizing plate, became 75° from the visual side with respect to the absorption axis direction of a polarizer. The thickness of the liquid crystal orientation-cured layer B was 1.5 μm, and the in-plane retardation Re(550) was 140 nm. Further, the liquid crystal orientation-cured layer B exhibited a refractive index characteristic of nx>ny=nz.

[0145] (Production of a laminate)

[0146] The liquid crystal orientation-cured layer A (H layer) and the liquid crystal orientation-cured layer B (Q layer) thus obtained were sequentially transferred on the polarizer side of the obtained polarizing plate. At this time, the transfer (attachment) was performed in such a manner that the angle between the absorption axis of the polarizer and the slow axis of the orientation-cured layer A became 15°, and the angle between the absorption axis of the polarizer and the slow axis of the orientation-cured layer B became 75°. Each of the transfers was performed via an ultraviolet-curable adhesive (thickness: 1.0 μm). In this way, a laminate precursor was obtained. Furthermore, the transfer (attachment) was performed while being subjected to roll transport. Further, the transfer (attachment) was performed in an environment in which the water vapor amount was 9.3 g / m2(23°C and 45% RH). 3

[0147] ​​The total thickness of the obtained laminate precursor was 36 μm, and the thickness ratio was 8.

[0148] The obtained long strip-shaped laminate precursor was cut along a direction at 45° with respect to the length direction and the width direction (a direction orthogonal to the length direction) to obtain a single-piece-shaped laminate precursor of 165 mm x 80 mm. Further, the length direction corresponds to the absorption axis direction of the polarizer.

[0149] Next, a surface protection film (thickness: 48 μm) was attached on the protective layer side of the polarizing plate of the laminate precursor. Further, the surface protection film was a film on which an adhesive layer (thickness: 10 μm) was formed on a PET-based film (thickness: 38 μm, moisture permeability: 18 g / m 2 ·24h).

[0150] Further, a separator (thickness: 38 μm, moisture permeability: 18 g / m 2 ·24h) was attached on the liquid crystal alignment and curing layer B (Q layer) side of the laminate precursor via an adhesive layer (thickness: 15 μm) to obtain a single-piece-shaped laminate of 165 mm x 80 mm.

[0151] Similarly, a total of 500 single-piece-shaped laminates of 165 mm x 80 mm were produced.

[0152] (Humidification treatment)

[0153] The obtained 500 single-piece-shaped laminates were overlapped to produce a laminate aggregate, and as shown in Figure 5 , a humidification treatment was performed on the laminates in a state where the laminates were placed so that the main surface of each laminate was at an angle of 90° with respect to the placement surface. Specifically, 500 laminates (laminate aggregate) were housed in a container having a prescribed size, and a humidification treatment was performed in a state where the laminates were placed so that the main surface of each laminate was at an angle of 90° with respect to the inner bottom surface (placement surface) of the container. Here, the long sides of the laminates were in contact with the inner bottom surface of the container, and the humidification treatment was performed in a state where a non-foamed polystyrene (PS) sheet was buried in the empty space in the container (a space between the main surface of the laminates at the front and rear ends of the laminate aggregate and the inner side surface of the container). The humidification treatment was performed for 24 hours at 23°C and 60% RH (water vapor amount: 12.4 g / m 3 ).

[0154] Thus, a polarizing plate with a phase difference layer was obtained.

[0155] [Example 2]

[0156] In the production of the polarizing plate, a TAC film (thickness: 27 μm) was used as the protective layer instead of the HC-COP film, and a polarizing plate with a phase difference layer was obtained similarly to Example 1.

[0157] [Comparative Example 1]

[0158] A polarizing plate with a retardation layer was obtained in the same manner as in Example 1, except that the long-stripe-shaped laminate precursor was not cut, and the long-stripe-shaped laminate was supplied to the humidification treatment in a rolled state.

[0159] [Comparative Example 2]

[0160] A polarizing plate with a retardation layer was obtained in the same manner as in Example 1, except that the laminate assembly was placed in a manner such that the main surface of each laminate was at an angle of 0° with respect to the placement surface (500 laminates were placed on the placement surface) in the humidification treatment.

[0161] [Comparative Example 3]

[0162] A polarizing plate with a retardation layer was obtained in the same manner as in Example 1, except that the humidification treatment was performed for 24 hours at 23°C and 45% RH (water vapor amount: 9.3 g / m 3 ).

[0163] [Reference Example 1]

[0164] A polarizer having a thickness of 22 μm was produced by uniaxially stretching a long roll of a PVA-based resin film having a thickness of 60 μm in the length direction using a roll stretching machine in a manner such that the total stretching ratio reached 6.0 times, while performing swelling, dyeing, crosslinking, and washing treatments, and finally performing a drying treatment. A TAC film with an HC layer (thickness: 71 μm) was attached to one surface of the obtained polarizer. Further, a polycarbonate resin retardation film (thickness: 58 μm) exhibiting reverse dispersion wavelength dependence and having Re(550) of 140 nm was attached to the other surface of the polarizer. Here, the attachment was performed in a manner such that the angle between the slow axis of the retardation film and the absorption axis of the polarizer was 45°. Thus, a polarizing plate with a retardation layer was obtained. The total thickness of the polarizing plate with a retardation layer was 151 μm, and the thickness ratio was 1.6. The polarizing plate with a retardation layer was cut to a size of 165 mm x 80 mm, and no warping was observed when it was left standing on a flat surface.

[0165] [Reference Example 2]

[0166] A polarizer with a thickness of 22 μm was fabricated in the same manner as in Reference Example 1. A TAC film with an HC layer (91 μm thick) was adhered to one side of the obtained polarizer, and a TAC film with a thickness of 80 μm was adhered to the other side to obtain a polarizer. A polarizer with a phase retardation layer was obtained in the same manner as in Example 1, except that the polarizer had a TAC film with an HC layer / polarizer / TAC film / adhesive layer / phase retardation layer (H layer) / adhesive layer / phase retardation layer (Q layer). The total thickness of the polarizer with a phase retardation layer was 197 μm, and the thickness was 48. The polarizer with a phase retardation layer was cut into 165 mm × 80 mm dimensions, and no warping was observed when it was placed still on a flat surface.

[0167] The following evaluations were performed on the embodiments and comparative examples. The evaluation results are summarized in Tables 1 and 2.

[0168] <Evaluation>

[0169] 1. Weight change per unit area

[0170] The lamination from the polarizer to the adhesive layer was measured using an electronic balance before and after humidification. Figure 4 The weight of the stacked portion 80 shown is calculated from the obtained measurement value.

[0171] 2. Warpage

[0172] The height of the highest part of the monolithic laminate precursor and the polarizer with the phase difference layer on the plane is measured when they are placed statically with the phase difference layer side as the plane side, and the warping is calculated.

[0173] Furthermore, "positive (+)" indicates that the warpage is convex on the resting surface side, and "negative (-)" indicates that the warpage is convex on the opposite side from the resting surface. Additionally, "(MD)" in the table corresponds to the conveying direction of the roller conveyor and the absorption shaft direction of the deflector.

[0174] 3. Appearance

[0175] The appearance of the polarizer with the phase retardation layer is determined by visual observation. Furthermore, the evaluation criteria are as follows.

[0176] (Evaluation Criteria)

[0177] Good: No dents detected.

[0178] Defect: Dent detected

[0179] Table 1

[0180]

[0181] Table 2

[0182]

[0183] As is apparent from Table 1, in Examples 1 and 2, the weight change due to the humidification treatment was in the range of 0.1 to 0.4%, and the warpage of the polarizing plate with a phase difference layer was in the range of -20 mm to +20 mm (when -, warpage in the MD direction was confirmed, and when +, warpage in the TD direction orthogonal to the MD direction was confirmed). Thus, in Examples 1 and 2, moisture was uniformly imparted to the plurality of laminates, and the uniformity of the correction state of the warpage generated in the laminate precursor was also improved.

[0184] On the other hand, in Comparative Example 2 in which the laminates were placed on the placement surface so as to overlap, unevenness was observed in the weight change due to the humidification treatment. Specifically, the laminate located on the upper side of the laminate aggregate was subjected to a smaller force than the laminate located on the lower side, the laminate located on the upper side absorbed more moisture than the laminate located on the lower side, and warpage in the opposite direction to the warpage generated in the laminate precursor was observed in the laminate located on the upper side. On the other hand, in the laminate located on the lower side, the warpage generated in the laminate precursor was improved. Thus, unevenness was observed in the correction state of the warpage generated in the laminate precursor. In addition, a dent was also observed in the obtained polarizing plate with a phase difference layer.

[0185] In Comparative Example 1 in which the humidification treatment was performed in a state of a roll, the weight per unit area did not change in the inner side portion wound into a roll, and the warpage was not improved.

[0186] In addition, as is apparent from the reference examples, such warpage can be said to be a technical problem peculiar to a polarizing plate with a phase difference layer having a total thickness that is thin and a ratio of the thickness of the polarizing plate to the total thickness that is large.

[0187] Industrial Applicability

[0188] The polarizing plate with a phase difference layer according to one embodiment of the present application is used as a polarizing plate with a phase difference layer for an image display device, and is particularly preferably used in an image display device that is curved or can be bent, folded, or rolled. As the image display device, a liquid crystal display device, an organic EL display device, and an inorganic EL display device can be exemplified.

[0189] Explanation of Symbols

[0190] 10 Polarizing plate

[0191] 11 Polarizer

[0192] 12 Protective layer

[0193] 20 Phase difference layer

[0194] 21 First phase difference layer (H layer)

[0195] 22 second phase difference layer (Q layer)

[0196] 31 first protective film

[0197] 32 second protective film

[0198] 90 layer stack precursor

[0199] 100 layer stack

Claims

1. A method for manufacturing a polarizer with a phase retardation layer, comprising: Prepare a laminated body, the laminated body sequentially comprising a first protective film, a polarizer including a polarizer and a protective layer disposed on at least one side of the polarizer, a phase retardation layer, and a second protective film, wherein the sum of the thickness of the polarizer and the thickness of the phase retardation layer is less than 50 μm, and the ratio of the thickness of the polarizer to the thickness of the phase retardation layer is greater than or equal to 5; and With the laminated body placed on the support surface, the laminated body is placed in a water vapor concentration of 10.5 g / m³. 3 Humidification treatment is performed under the above conditions. in, The laminate is placed at an angle relative to the mounting surface. The humidification process is performed while multiple of the aforementioned laminates are arranged in a stacked configuration. The manufacturing method includes laminating the polarizer and the phase difference layer using an active energy line curing adhesive.

2. The manufacturing method according to claim 1, comprising stacking the polarizer and the phase difference layer to obtain a laminate precursor.

3. The manufacturing method according to claim 2, comprising cutting the laminate precursor to form a single sheet.

4. The manufacturing method according to any one of claims 1 to 3, wherein, The moisture permeability of the first protective film at 40°C and 92% RH is 30 g / m³. 2 • Less than 24 hours.

5. The manufacturing method according to any one of claims 1 to 3, wherein, The moisture permeability of the second protective film at 40°C and 92% RH is 30 g / m³. 2 • Less than 24 hours.

6. The manufacturing method according to any one of claims 1 to 3, comprising stacking the polarizer and the phase difference layer while roller conveying them.

7. The manufacturing method according to any one of claims 1 to 3, wherein, The cured thickness of the active energy ray-cured adhesive is greater than 0.4 μm.

8. The manufacturing method according to any one of claims 1 to 3, wherein, The laminate has an adhesive layer disposed on the side of the phase retardation layer where the polarizer is not located. The weight per unit area of ​​the laminated portion of the polarizer, the phase difference layer and the adhesive layer produced by the humidification treatment increases by more than 0.1%.

9. The manufacturing method according to any one of claims 1 to 3, wherein, The humidification process takes more than 6 hours.

10. The manufacturing method according to any one of claims 1 to 3, wherein, The amount of water vapor during the humidification treatment is 10.5 g / m³. 3 ~30g / m 3 .

11. The manufacturing method according to any one of claims 1 to 3, wherein the water vapor content is 10.2 g / m³. 3 The polarizer and the phase difference layer are stacked under the following conditions.

12. The manufacturing method according to any one of claims 1 to 3, wherein, The amount of water vapor during the humidification process is 0.5 g / m more than the amount of water vapor during the stacking of the polarizer and the phase difference layer. 3 above.

13. The manufacturing method according to any one of claims 1 to 3, wherein, The moisture permeability of the phase retardation layer or the protective layer at 40°C and 92% RH is 300 g / m³. 2 ·More than 24h.

14. The manufacturing method according to any one of claims 1 to 3, wherein, In the polarizer, a protective layer is provided only on the side of the polarizer where the phase difference layer is not configured.

15. The manufacturing method according to any one of claims 1 to 3, wherein, The centroid of the polarizer in the thickness direction is closer to the phase retardation layer than the centroid of the stacked portion of the polarizer and the phase retardation layer in the thickness direction.

16. The manufacturing method according to any one of claims 1 to 3, wherein, The phase retardation layer is an orientation-cured layer of a liquid crystal compound.

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