Laminate and method for manufacturing polarizing plate with retardation layer

Abstract

To provide a polarizing plate with a retardation layer whose warpage is prevented.SOLUTION: A laminate according to an embodiment of the present invention is a laminate having a first protective film, a polarizing plate including a polarizer and a protective layer arranged on at least one side of the polarizer, a retardation layer, and a second protective film in this order. The total of the thickness of the polarizing plate and the thickness of the retardation layer is 70 μm or less. The center in the thickness direction of the polarizer is located within a range of 10% or less of half the thickness of the laminate from the center in the thickness direction of the laminate.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a laminate and a method for manufacturing a polarizing plate with a retardation layer.

Background Art

[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) have been rapidly spreading. Typically, a polarizing plate and a retardation plate are used in image display devices. 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 curving, bending, folding, and winding an image display device has been studied using a flexible substrate (for example, a resin substrate). As such a polarizing plate with a retardation layer used in an image display device, a thin polarizing plate with a retardation layer is desired. However, a thin polarizing plate with a retardation layer has a problem that warping is likely to occur.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention has been made to solve the above conventional problems, and its main object is to provide a polarizing plate with a retardation layer in which warping is suppressed.

Means for Solving the Problems

[0005] According to an embodiment of the present invention, a laminate is provided. This laminate is a laminate having, in this 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 retardation layer, and a second protective film, wherein the sum of the thickness of the polarizing plate and the thickness of the retardation layer is 70 μm or less, and the center of the polarizer in the thickness direction is located within a range of 10% or less of half the thickness of the laminate from the center of the laminate in the thickness direction. In one embodiment, the ratio of the thickness of the polarizing plate to the thickness of the retardation layer is 5 or more. In one embodiment, in the polarizing plate, the protective layer is disposed only on the side where the retardation layer of the polarizer is not disposed. In one embodiment, the retardation layer is an alignment cured layer of a liquid crystal compound. In one embodiment, the thickness of the first protective film is 15 μm or more and 90 μm or less. In one embodiment, the thickness of the second protective film is 40 μm or more. According to another embodiment of the present invention, a method for manufacturing a polarizing plate with a retardation layer is provided. This manufacturing method includes preparing the above laminate and storing the above laminate. In one embodiment, the manufacturing method includes laminating the polarizing plate and the retardation layer to obtain a laminate precursor. In one embodiment, the manufacturing method includes cutting the laminate precursor into a sheet form. In one embodiment, the manufacturing method includes laminating the polarizing plate and the retardation layer using an active energy ray curable adhesive. In one embodiment, the thickness of the active energy ray curable adhesive after curing is 0.4 μm or more. In one embodiment, the manufacturing method includes performing a humidification treatment on the laminate before storage.

Advantages of the Invention

[0006] According to an embodiment of the present invention, in a laminate having a polarizing plate and a retardation layer, by positioning the center of the polarizer within a predetermined range, a polarizing plate with a retardation layer in which warpage is suppressed can be obtained.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

[0009] (Definitions of Terms and Symbols) The definitions of terms and symbols in this specification are as follows. (1) Refractive Index (nx, ny, nz) “nx” is the refractive index in the direction in which the in-plane refractive index is maximum (i.e., the slow axis direction), “ny” is the refractive index in the direction orthogonal to the slow axis in the plane (i.e., the fast axis direction), and “nz” is the refractive index in the thickness direction. (2) In-Plane Retardation (Re) “Re(λ)” is the in-plane retardation measured with light of wavelength λ nm at 23°C. For example, “Re(550)” is the in-plane retardation measured with light of wavelength 550 nm at 23°C. Re(λ) is obtained by the formula: Re(λ) = (nx - ny) × d when the thickness of the layer (film) is d (nm). (3) Retardation in the Thickness Direction (Rth) 「Rth(λ)」 is the retardation in the thickness direction measured with light of wavelength λ nm at 23°C. For example, 「Rth(550)」 is the retardation in the thickness direction measured with light of wavelength 550 nm at 23°C. Rth(λ) can be 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 in this specification, the angle includes both clockwise and counterclockwise directions with respect to the reference direction. Therefore, for example, 「45°」 means ±45°.

[0010] A method for manufacturing a polarizing plate with a retardation layer according to one embodiment of the present invention includes preparing a laminate having a polarizing plate including a polarizer and a retardation layer, and subjecting the laminate to a humidification treatment by placing it in a predetermined environment.

[0011] A. Laminate FIG. 1 is a schematic cross-sectional view showing the schematic configuration of a laminate according to the first embodiment of the present invention. The laminate 100 has a first protective film 31, a polarizing plate 10, a retardation layer 20, and a second protective film 32 in this order from the viewing side. In the illustrated example, the polarizing plate 10 includes a polarizer 11 and a protective layer 12 disposed on the viewing side of the polarizer 11 (the side where the retardation layer 20 is not disposed), and no protective layer is disposed between the polarizer 11 and the retardation layer 20. According to such a configuration, for example, the thickness, total thickness, and thickness ratio of the polarizing plate described below can be achieved well.

[0012] Although not shown, the other side of the polarizer 11 (between the polarizer 11 and the retardation layer 20) may further include a protective layer.

[0013] FIG. 2 is a schematic cross-sectional view showing a schematic configuration of a laminate according to a second embodiment of the present invention. In the first embodiment, the retardation layer 20 is a single layer, whereas in the second embodiment, the retardation layer 20 has a laminate structure including a first retardation layer 21 and a second retardation layer 22. Different from the illustrated example, the retardation layer 20 may have a laminate structure of three or more layers.

[0014] Although not shown, the laminate may further have other functional layers. The type, characteristics, number, combination, arrangement, etc. of the functional layers that the laminate can have can be appropriately set according to the purpose. For example, the laminate may further have a conductive layer or an anisotropic base material with a conductive layer. The conductive layer or the anisotropic base material with a conductive layer is typically disposed between the retardation layer 20 and the second protective film 32. Note that a laminate (polarizing plate with a retardation layer) having a conductive layer or an anisotropic base material with a conductive layer is applied, for example, to an image display device in which a touch sensor is incorporated inside the image display panel. As another example, the laminate may further have other retardation layers. The optical characteristics (for example, refractive index characteristics, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, arrangement, etc. of the other retardation layers can be appropriately set according to the purpose. As a specific example, on the viewing side of the polarizer 11, another retardation layer (typically, a layer imparting an (elliptical) polarization function, a layer imparting an ultra-high retardation) for improving the visibility when viewing through polarized sunglasses may be provided. By having such a layer, excellent visibility can be realized even when the display screen is viewed through a polarizing lens such as polarized sunglasses. Therefore, the obtained polarizing plate with a retardation layer can also be suitably applied to an image display device that can be used outdoors.

[0015] Each member constituting the laminate can be laminated via any suitable adhesive layer (not shown). Specific examples of the adhesive layer include an adhesive layer and an adhesive agent layer. For example, the first protective film 31 is bonded to the polarizing plate 10 via an adhesive agent layer. The first protective film 31 may be peeled off until the retardation film - attached polarizing plate obtained according to the embodiment of the present invention is put into use (until it is laminated on the image display panel), or during the manufacturing process of the final product (image display device), or may be mounted on the final product as it is.

[0016] For example, the second protective film 32 is bonded to the retardation layer 20 via an adhesive agent layer. Practically, the second protective film 32 can function as a peeling film (separator) that is temporarily attached until the retardation film - attached polarizing plate obtained according to the embodiment of the present invention is put into use. By temporarily attaching the peeling film, for example, the adhesive agent layer is protected and roll formation of the laminate becomes possible.

[0017] For example, the retardation layer 20 is bonded to the polarizing plate 10 via an adhesive layer (preferably using an active energy ray - curable adhesive). When the retardation layer 20 has a laminated structure of two or more layers, each retardation layer is bonded via an adhesive layer (preferably using an active energy ray - curable adhesive).

[0018] A - 1. Polarizing Plate The above - mentioned polarizing plate includes a polarizer and a protective layer. The thickness of the polarizing plate depends on the number of protective layers included, but is preferably 20 μm or more, more preferably 25 μm or more. On the other hand, the thickness of the polarizing plate is preferably 40 μm or less, more preferably 36 μm or less, and even more preferably 33 μm or less. It should be noted that when an adhesive layer (for example, an adhesive agent layer) is used when laminating the polarizer and the protective layer, the thickness of the adhesive layer is not included in the thickness of the polarizing plate.

[0019] The above polarizer is typically a resin film containing a dichroic substance (e.g., iodine). Examples of the resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA)-based films, partially formalized PVA-based films, and ethylene-vinyl acetate copolymer-based partially saponified films.

[0020] 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.

[0021] The polarizer preferably exhibits absorption dichroism at any wavelength in the range of 380 nm to 780 nm. The single transmittance of the polarizer is, for example, 41.5% to 46.0%, preferably 42.0% to 46.0%, and more preferably 44.5% to 46.0%. The degree of polarization of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and even more preferably 99.9% or more.

[0022] The above protective layer can be formed of any suitable film that can be used as a protective layer for the polarizer. Specific examples of the material that is the main component of the film include cellulose-based resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, polysulfone-based, polystyrene-based, cycloolefin-based such as polynorbornene, polyolefin-based, (meth)acrylic-based, acetate-based resins, and the like.

[0023] The polarizer with a retardation layer obtained according to an embodiment of the present invention is typically disposed on the viewing side of an image display device, and the protective layer 12 is disposed on the viewing side. Therefore, the protective layer 12 may be subjected to surface treatments such as hard coat (HC) treatment, antireflection treatment, anti-sticking treatment, antiglare treatment, etc., as necessary.

[0024] 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 10 μm to 30 μm. When the above surface treatment is performed, the thickness of the protective layer 12 is the thickness including the thickness of the surface treatment layer.

[0025] In one embodiment, the protective layer (not shown) disposed between the polarizer 11 and the retardation layer 20 is preferably optically isotropic. As used herein, "optically isotropic" means that the in-plane retardation Re(550) is 0 nm to 10 nm and the retardation Rth(550) in the thickness direction is -10 nm to +10 nm. The thickness of the protective layer disposed between the polarizer 11 and the retardation layer 20 is preferably 5 μm to 80 μm, more preferably 10 μm to 40 μm, and even more preferably 10 μm to 30 μm.

[0026] The polarizing plate can be produced by any suitable method. Specifically, the polarizing plate may include a polarizer made from a single-layer resin film, or may include a polarizer obtained using a laminate of two or more layers.

[0027] The method for manufacturing a polarizer from the above single-layer resin film typically includes subjecting the resin film to a dyeing treatment with a dichroic substance such as iodine or a dichroic dye and a stretching treatment. As the resin film, as described above, for example, a hydrophilic polymer film such as a polyvinyl alcohol (PVA) - based film, a partially formalized PVA - based film, or a partially saponified ethylene - vinyl acetate copolymer - based film is used. The method may further include an insolubilization treatment, a swelling treatment, a crosslinking treatment, etc. A polarizing plate can be obtained by laminating a protective layer on at least one of the obtained polarizers. Since such a manufacturing method is well - known and commonly used in the art, a detailed description is omitted.

[0028] Specific examples of the polarizer obtained using the above laminate include a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate. 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 applying a PVA-based resin solution to the resin substrate and drying it to form a PVA-based resin layer on the resin substrate to obtain a laminate of the resin substrate and the PVA-based resin layer; stretching and dyeing the laminate to make the PVA-based resin layer a polarizer. In the present embodiment, preferably, a PVA-based resin layer containing a halide and a polyvinyl alcohol-based resin is formed on one side of the resin substrate. Stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching it. Further, stretching may further include air stretching the laminate at a high temperature (for example, 95 °C or higher) before stretching in the aqueous boric acid solution, if necessary. In addition, in the present embodiment, preferably, the laminate is subjected to a drying shrinkage treatment in which it is heated while being conveyed in the longitudinal direction to shrink by 2% or more in the width direction. Typically, the manufacturing method of the present embodiment includes sequentially performing an air-assisted stretching treatment, a dyeing treatment, a water stretching treatment, and a drying shrinkage treatment on the laminate. By introducing the auxiliary stretching, even when PVA is applied on a thermoplastic resin, it is possible to enhance the crystallinity of PVA and achieve high optical properties. At the same time, by enhancing the orientation of PVA in advance, problems such as a decrease in the orientation of PVA or dissolution when immersed in water in the subsequent dyeing process or stretching process can be prevented, and high optical properties can be achieved. Further, when the PVA-based resin layer is immersed in a liquid, the disturbance of the orientation of polyvinyl alcohol molecules and the decrease in the orientation can be suppressed as compared with the case where the PVA-based resin layer does not contain a halide. Thereby, the optical properties of the polarizer obtained through treatment steps such as a dyeing treatment and a water stretching treatment, which are performed by immersing the laminate in a liquid, can be improved. Furthermore, by shrinking the laminate in the width direction by the drying shrinkage treatment, the optical properties can be improved.The obtained resin substrate / polarizer laminate may be used as it is (i.e., the resin substrate may be used as a protective layer for the polarizer), and an arbitrary appropriate protective layer according to the purpose may be laminated on the peeled surface of the resin substrate peeled from the resin substrate / polarizer laminate or on the surface opposite to the peeled surface and used. Details of such a method for manufacturing a polarizer are described, for example, in JP-A-2012-73580 and Japanese Patent No. 6470455. The entire descriptions of these publications are incorporated herein by reference.

[0029] A-2. Retardation layer The thickness of the above-mentioned retardation layer depends on its configuration (whether it is a single layer or has a laminated structure), but is preferably 8 μm or less, more preferably 5 μm or less. On the other hand, the thickness of the retardation layer is, for example, 1 μm or more. When the retardation layer has a laminated structure, the "thickness of the retardation layer" means the sum of the thicknesses of the respective retardation layers. Specifically, the "thickness of the retardation layer" does not include the thickness of the adhesive layer (for example, the adhesive layer).

[0030] As the above-mentioned retardation layer, preferably, an alignment cured layer (liquid crystal alignment cured layer) of a liquid crystal compound is used. By using a liquid crystal compound, the difference between nx and ny of the obtained retardation layer can be made significantly larger than that of a non-liquid crystal material, so that the thickness of the retardation layer for obtaining a desired in-plane retardation can be made significantly smaller. Therefore, a significant thinning of the polarizer with a retardation layer can be achieved. In this specification, the "alignment cured layer" refers to a layer in which a liquid crystal compound is aligned in a predetermined direction within the layer and its alignment state is fixed. The "alignment cured layer" is a concept that includes an alignment cured layer obtained by curing a liquid crystal monomer as described later. In the retardation layer, typically, rod-shaped liquid crystal compounds are aligned in the direction of the slow axis of the retardation layer (homogeneous alignment).

[0031] The above liquid crystal alignment curing layer can be formed by subjecting the surface of a predetermined substrate to an alignment treatment, applying a coating liquid containing a liquid crystal compound to the surface to align the liquid crystal compound in a direction corresponding to the alignment treatment, and fixing the alignment state. As the alignment treatment, any appropriate alignment treatment can be adopted. Specifically, mechanical alignment treatment, physical alignment treatment, and chemical alignment treatment can be mentioned. Specific examples of mechanical alignment treatment include rubbing treatment and stretching treatment. Specific examples of physical alignment treatment include magnetic field alignment treatment and electric field alignment treatment. Specific examples of chemical alignment treatment include oblique evaporation method and photo-alignment treatment. The treatment conditions of various alignment treatments can be any appropriate conditions according to the purpose.

[0032] The alignment of the liquid crystal compound is performed by treating at a temperature at which the liquid crystal compound exhibits a liquid crystal phase according to the type of the liquid crystal compound. By performing such a temperature treatment, the liquid crystal compound takes a liquid crystal state and aligns according to the alignment treatment direction on the substrate surface.

[0033] In one embodiment, the fixing of the alignment state is performed by cooling the liquid crystal compound aligned as described above. When the liquid crystal compound is a polymerizable monomer or a crosslinkable monomer, the fixing of the alignment state is performed by subjecting the liquid crystal compound aligned as described above to a polymerization treatment or a crosslinking treatment.

[0034] Specific examples of the liquid crystal compound and details of the method for forming the alignment curing layer are described in Japanese Patent Application Laid-Open No. 2006-163343. The description of the said publication is incorporated herein by reference.

[0035] As described above, the retardation layer 20 may be a single layer or may have a laminated structure of two or more layers.

[0036] As shown in FIG. 1, in one embodiment where the retardation layer 20 is a single layer, the retardation layer 20 can function as a λ / 4 plate. Specifically, Re(550) of the retardation layer is preferably 100 nm to 180 nm, more preferably 110 nm to 170 nm, and even more preferably 110 nm to 160 nm. The thickness of the retardation layer can be adjusted so as to obtain a desired in-plane retardation of the λ / 4 plate. When the retardation layer is the above-described liquid crystal alignment solidification layer, its thickness is, for example, 1.0 μm to 2.5 μm. In this embodiment, the angle formed by the slow axis of the retardation layer and the absorption axis of the polarizer is preferably 40° to 50°, more preferably 42° to 48°, and even more preferably 44° to 46°. In this embodiment, the retardation layer preferably exhibits an inverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light. Note that in this embodiment, the laminate may further include a layer (another retardation layer, not shown) having a refractive index characteristic of nz>nx = ny disposed between the retardation layer 20 and the second protective film 32.

[0037] In another embodiment where the retardation layer 20 is a single layer, the retardation layer 20 can function as a λ / 2 plate. Specifically, Re(550) of the retardation layer is preferably 200 nm to 300 nm, more preferably 230 nm to 290 nm, and even more preferably 230 nm to 280 nm. The thickness of the retardation layer can be adjusted so as to obtain a desired in-plane retardation of the λ / 2 plate. When the retardation layer is the above-described liquid crystal alignment solidification layer, its thickness is, for example, 2.0 μm to 4.0 μm. In this embodiment, the angle formed by the slow axis of the retardation layer and the absorption axis of the polarizer is preferably 10° to 20°, more preferably 12° to 18°, and even more preferably 12° to 16°.

[0038] As shown in Fig. 2, when the retardation layer 20 has a laminated structure, the retardation layer 20 has, for example, a two-layer laminated structure in which a first retardation layer (H layer) 21 and a second retardation layer (Q layer) 22 are arranged in order from the polarizer side. The H layer can typically function as a λ / 2 plate, and the Q layer can typically function as a λ / 4 plate. Specifically, 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; Re(550) of the Q layer is preferably 100 nm to 180 nm, more preferably 110 nm to 170 nm, still more preferably 110 nm to 150 nm. The thickness of the H layer can be adjusted so as to obtain a desired in-plane retardation of the λ / 2 plate. When the H layer is the above-described liquid crystal alignment cured layer, its thickness is, for example, 2.0 μm to 4.0 μm. The thickness of the Q layer can be adjusted so as to obtain a desired in-plane retardation of the λ / 4 plate. When the Q layer is the above-described liquid crystal alignment cured layer, its thickness 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°, still more preferably 12° to 16°; 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°, still more preferably 72° to 76°. When the retardation layer 20 has a laminated structure, each layer (for example, the H layer and the Q layer) may exhibit an inverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light, a positive wavelength dispersion characteristic in which the retardation value decreases according to the wavelength of the measurement light, or a flat wavelength dispersion characteristic in which the retardation value hardly changes depending on the wavelength of the measurement light.

[0039] The retardation layer 20 (each layer when having a laminated structure) typically exhibits a refractive index characteristic showing a relationship of nx > ny = nz. Note that "ny = nz" includes not only the case where ny and nz are exactly equal but also the case where they are substantially equal. Therefore, within a range that does not impair the effects of the present invention, ny > nz or ny < nz may occur. The Nz coefficient of the retardation layer is preferably 0.9 to 1.5, more preferably 0.9 to 1.3.

[0040] As described above, the retardation layer is preferably a liquid crystal alignment solidified layer. Examples of the liquid crystal compound include a liquid crystal compound (nematic liquid crystal) having a nematic liquid crystal phase. As such a liquid crystal compound, for example, a liquid crystal polymer or a liquid crystal monomer can be used. The mechanism for expressing the liquid crystallinity 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.

[0041] 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 alignment state of the liquid crystal monomer can be fixed by polymerizing or crosslinking (i.e., curing) the liquid crystal monomer. After the liquid crystal monomers are aligned, for example, if the liquid crystal monomers are polymerized or crosslinked with each other, the alignment state can be fixed thereby. Here, a polymer is formed by polymerization, and a three-dimensional network structure is formed by crosslinking, but these are non-liquid crystalline. Therefore, in the formed retardation layer, for example, a transition from a liquid crystal phase, a glass phase, or a crystal phase due to a temperature change peculiar to the liquid crystalline compound does not occur. As a result, the retardation layer becomes an extremely stable retardation layer that is not affected by temperature changes.

[0042] The temperature range in which the liquid crystal monomer exhibits liquid crystallinity varies depending on its 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.

[0043] As the above liquid crystal monomer, any suitable liquid crystal monomer can be adopted. For example, polymerizable mesogenic compounds described in JP-T-2002-533742 (WO00 / 37585), EP358208 (US5211877), EP66137 (US4388453), WO93 / 22397, EP0261712, DE19504224, DE4408171, GB2280445, etc. can be used. Specific examples of such polymerizable mesogenic compounds include, for example, LC242 with the trade name of BASF, E7 with the trade name of Merck, and LC-Sillicon-CC3767 with the trade name of Wacker-Chem. As the liquid crystal monomer, a nematic liquid crystal monomer is preferred.

[0044] A-3. Relationship between the thickness of the polarizing plate and the retardation layer The sum of the thickness of the above polarizing plate and the thickness of the above retardation layer (sometimes simply referred to as "total thickness") is 70 μm or less, preferably 50 μm or less, more preferably 45 μm or less, and even more preferably 40 μm or less. In such a total thickness, the problem of warping tends to occur easily. On the other hand, the total thickness is, for example, 25 μm or more.

[0045] The ratio of the thickness of the above polarizing plate to the thickness of the above retardation layer (thickness of the polarizing plate / thickness of the retardation layer, sometimes simply referred to as "thickness ratio") is, for example, 5 or more, preferably 8 or more, more preferably 10 or more. In such a thickness ratio, the problem of warping tends to occur easily. On the other hand, the thickness ratio is preferably 30 or less, more preferably 25 or less.

[0046] A-4. First protective film The first protective film 31 can be formed of any suitable material. Specific examples of the forming material include polyester-based polymers such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); cellulose-based polymers such as diacetyl cellulose and triacetyl cellulose; polycarbonate-based polymers; (meth)acrylic-based polymers such as polymethyl methacrylate; cycloolefin-based polymers such as polynorbornene. These may be used alone or in combination of two or more.

[0047] The thickness of the first protective film is, for example, 10 μm or more and 100 μm or less, preferably 15 μm or more and 90 μm or less, more preferably 25 μm or more and 80 μm or less.

[0048] The first protective film preferably has a moisture permeability at 40 °C and 92% RH of 30 g / m 2 ·24 h or less, more preferably 20 g / m 2 ·24 h or less. According to such a first protective film, for example, in the humidification treatment described later, moisture can be appropriately imparted to the laminate (preferably, a polarizer). On the other hand, the moisture permeability of the first protective film at 40 °C and 92% RH is, for example, 5 g / m 2 ·24 h or more.

[0049] As described above, the first protective film 31 can be bonded to the polarizing plate 10 via an adhesive layer. Any suitable configuration can be adopted as the adhesive layer. Specific examples include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, urethane adhesives, epoxy adhesives, and polyether adhesives. By adjusting the type, number, combination, and blending ratio of the monomers forming the base resin of the adhesive, as well as the blending amount of the crosslinking agent, reaction temperature, reaction time, etc., an adhesive having desired properties according to the purpose can be prepared. The base resin of the adhesive may be used alone or in combination of two or more. 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 μm to 15 μm. The storage elastic modulus of the adhesive layer at 25°C is, for example, 1.0×10 5 Pa to 1.0×10 7 Pa.

[0050] In one embodiment, a laminate (hereinafter referred to as "surface protective film") on which the above adhesive layer is formed in advance is used on the first protective film. The thickness of the surface protective film is preferably 20 μm to 100 μm, more preferably 30 μm to 90 μm. As described above, when the first protective film is peeled off, it can be peeled off together with the adhesive layer (along with the surface protective film).

[0051] A-5. Second Protective Film The second protective film 32 can be composed of any suitable plastic film. Specific examples of the plastic film include polyethylene terephthalate (PET) film, polyethylene film, and polypropylene film. As described above, the second protective film 32 can function as a separator. Specifically, as the second protective film 32, a plastic film whose surface is coated with a release agent is preferably used. Specific examples of the release agent include silicone-based release agents, fluorine-based release agents, and long-chain alkyl acrylate-based release agents.

[0052] The thickness of the second protective film is, for example, 30 μm or more, preferably 40 μm or more, more preferably 45 μm or more, and even more preferably 50 μm or more. On the other hand, the thickness of the second protective film is, for example, 100 μm or less, preferably 80 μm or less.

[0053] The second protective film preferably has a moisture permeability at 40 °C and 92% RH of 30 g / m 2 ·24 h or less, more preferably 20 g / m 2 ·24 h or less. According to such a second protective film, for example, in the humidification treatment described below, moisture can be appropriately imparted to the laminate (preferably, a polarizer). On the other hand, the moisture permeability of the second protective film at 40 °C and 92% RH is, for example, 5 g / m 2 ·24 h or more.

[0054] A-6. Production of laminate The laminate 100 can be obtained, for example, by laminating a polarizing plate 10 and a retardation layer 20 to produce a laminate precursor, and then laminating a first protective film 31 and a second protective film 32 on the obtained laminate precursor.

[0055] The lamination of the polarizing plate 10 and the retardation layer 20 is performed, for example, while roll-conveying them (so-called roll-to-roll). Lamination is typically performed by transferring a liquid crystal alignment cured layer formed on a substrate. As shown in FIG. 2, when the retardation layer has a laminated structure, each retardation layer may be sequentially laminated (transferred) onto the polarizing plate, or a laminate of the retardation layers may be laminated (transferred) onto the polarizing plate.

[0056] The above transfer is performed, for example, using an active energy ray-curable adhesive. The thickness after curing of the active energy ray-curable adhesive (thickness of the adhesive layer) is, for example, 0.2 μm to 3.0 μm, preferably 0.4 μm to 2.0 μm, and more preferably 0.6 μm to 1.5 μm. The above warp is caused by, for example, an adhesive used for laminating a polarizing plate and a retardation layer (specifically, shrinkage during curing of the active energy ray-curable adhesive), and warping may occur in the laminate precursor obtained by laminating the polarizing plate 10 and the retardation layer 20.

[0057] FIG. 3 is a cross-sectional view showing an example of the warped state of the laminate precursor. In FIG. 3, the cross-section of the laminate precursor is omitted from hatching for easy viewing. In the example shown in FIG. 3, the laminate precursor 90 has a convex warp on the side of the polarizing plate 10. The warp tends to occur along the absorption axis direction of the polarizing plate 10 (polarizer 11).

[0058] The lamination of the polarizing plate 10 and the retardation layer 20 is preferably performed under the following environment. The amount of water vapor (A1) is more preferably 6.0 g / m 3 and preferably performed under the following environment. The amount of water vapor (A1) in the lamination is more preferably 6.0 g / m 3 ~10.0 g / m 3 and even more preferably 8.0 g / m 3 ~9.5 g / m 3 By performing the lamination in an environment where the amount of water vapor (A1) is in such a range, for example, the effect of the humidification treatment described later becomes remarkable. Such an amount of water vapor (A1) in the lamination can be realized, for example, by changing the relative humidity according to the temperature in the range of 18°C to 25°C. The amount of water vapor (A1) can be realized, for example, by setting the relative humidity to 65% RH or less when the temperature is 18°C; also, for example, by setting the relative humidity to 55% RH or less when the temperature is 20°C; also, for example, by setting the relative humidity to 45% RH or less when the temperature is 23°C. Note that the lower limit of the relative humidity can be, for example, 30% RH.

[0059] As described above, when the laminate further has other functional layers (for example, a conductive layer, other retardation layers), the functional layers can be laminated or formed at a predetermined position by any suitable method.

[0060] The lamination of the laminate precursor having the polarizing plate 10 and the retardation layer 20 and the first protective film 31 is performed, for example, by bonding the above 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 retardation layer 20 and the second protective film 32) is preferably 10 μm to 20 μm.

[0061] The above laminate can be subjected to a humidification treatment. By subjecting the laminate to a humidification treatment, moisture is imparted to the laminate (preferably, the polarizer), and the warpage generated after the lamination of the above polarizing plate and the retardation layer can be corrected. In addition, it is preferable that the laminate does not have warpage during storage described later.

[0062] The above humidification treatment is performed, for example, by placing the laminate in an environment of 18°C to 34°C and 60% RH to 90% RH. The amount of water vapor (A2) during the humidification treatment is preferably 10.5 g / m 3 ~30 g / m 3 and more preferably 11 g / m 3 ~20 g / m 3 is.

[0063] The amount of water vapor (A2) during the above humidification treatment can be realized, for example, by setting the relative humidity to 80% RH or more when the temperature is 18°C; also, for example, when the temperature is 20°C, by setting the relative humidity to 60% RH or more; also, for example, when the temperature is 23°C, by setting the relative humidity to 50% RH or more. The upper limit of the relative humidity can be, for example, 100% RH.

[0064] In one embodiment, the laminate is humidified in an environment that satisfies a water vapor amount greater than the above water vapor amount (A1). More specifically, the difference between the water vapor amount (A2) during the humidification treatment and the above water vapor amount (A1) is preferably 0.5 g / m 3 or more, more preferably 1.0 g / m 3 ~28 g / m 3 and even more preferably 1.0 g / m 3 ~12 g / m 3 and particularly preferably 1.5 g / m 3 ~10 g / m 3 and most preferably 1.5 g / m 3 ~8 g / m 3 is. By humidifying under such conditions, an appropriate amount of moisture can be imparted to the laminate. More specifically, moisture can be imparted to the laminate without shrinking the laminate. In the humidification treatment, if the amount of moisture imparted to the laminate is too large, for example, warping with the initial warp and the opposite convex direction and / or warping in a direction orthogonal to the direction of the initial warp in the plane may occur.

[0065] The time of the humidification treatment is preferably 6 hours or more, more preferably 12 hours or more, and even more preferably 18 hours or more. On the other hand, the time of the humidification treatment is, for example, 48 hours or less.

[0066] A-7. Positional relationship between the polarizer and the laminate In the laminate, the center in the thickness direction of the polarizer is located within a range of 10% or less of half the thickness of the laminate from the center in the thickness direction of the laminate. According to such a positional relationship, the occurrence of warping due to changes in temperature and humidity can be suppressed. As a result, a retardation film-attached polarizing plate with suppressed warping can be obtained. The center in the thickness direction of the polarizer is preferably located within a range of 8% or less of half the thickness of the laminate from the center in the thickness direction of the laminate, and more preferably located within a range of 4% or less of half the thickness of the laminate from the center in the thickness direction of the laminate.

[0067] FIG. 4 is a diagram for explaining the positional relationship between the center of the polarizer and the center of the laminate. In FIG. 4, for ease of viewing the figure, hatching is omitted in some layers of the laminate. The laminate 100 includes a surface protection film 50 including a first protective film 31 and an adhesive layer 52, a polarizing plate 10 including a protective layer 12 and a polarizer 11, an adhesive layer 54, a first retardation layer 21, an adhesive layer 56, a second retardation layer 22, an adhesive layer 58, and a second protective film (separator) 32 in this order. As described above, in the thickness direction, the distance d between the center 11a of the polarizer 11 and the center 100a of the laminate 100 is set within a range of 10% or less of half of the thickness T of the laminate 100. In the illustrated example, in the thickness direction, the center 11a of the polarizer 11 is located closer to the retardation layers 21 and 22 than the center 100a of the laminate 100, but may be located closer to the protective layer 12 than the center 100a of the laminate 100. In one embodiment, the control of the position of the center of the polarizer with respect to the center of the laminate is performed by adjusting the thickness of the first protective film and the thickness of the second protective film.

[0068] B. Method for manufacturing a polarizing plate with a retardation layer The method for manufacturing a polarizing plate with a retardation layer according to one embodiment of the present invention includes preparing the above laminate and storing (including transportation) the laminate. Specifically, the above laminate is used as a polarizing plate with a retardation layer after storage. According to the above laminate, warping can be suppressed during storage (specifically, due to changes in temperature and humidity). As a result, the obtained polarizing plate with a retardation layer has warping suppressed and can be favorably laminated on, for example, an image display panel.

Examples

[0069] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. The thickness and moisture permeability are values measured by the following measurement methods. Also, unless otherwise specified, "parts" and "%" in the examples and comparative examples are based on weight. <Thickness> The thickness of 10 μm or less was measured using a scanning electron microscope (manufactured by JEOL Ltd., product name "JSM-7100F"). The thickness exceeding 10 μm was measured using a digital micrometer (manufactured by Anritsu Corporation, product name "KC-351C"). <Moisture permeability The moisture permeability was determined by the cup method (JIS Z 0208).

[0070] [Example 1] (Production of polarizing plate) As a thermoplastic resin substrate, an amorphous isophthalic acid copolymerized polyethylene terephthalate film (thickness: 100 μm) in a long strip shape with a Tg of about 75 °C was used, and one side of this resin substrate was subjected to corona treatment. 13 parts by weight of potassium iodide was added to 100 parts by weight of a PVA-based resin obtained by mixing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Gosei Chemical Industry Co., Ltd., trade name "Gosefimer") at a ratio of 9:1, and the mixture was dissolved in water to prepare a PVA aqueous solution (coating solution). The above PVA aqueous solution was applied to the corona-treated surface of the resin substrate and dried at 60 °C to form a PVA-based resin layer with a thickness of 13 μm, thereby producing a laminate. The obtained laminate was uniaxially stretched 2.4 times in the longitudinal direction (longitudinal direction) in an oven at 130 °C (air-assisted stretching treatment). Next, the laminate was immersed in an insolubilizing bath at a liquid temperature of 40 °C (an aqueous boric acid solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insolubilizing treatment). Next, the laminate was immersed in a dyeing bath at a liquid temperature of 30 °C (an aqueous iodine solution obtained by mixing iodine and potassium iodide at a weight ratio of 1:7) for 60 seconds while adjusting the concentration so that the single transmittance (Ts) of the finally obtained polarizer became a desired value (dyeing treatment). Next, the laminate was immersed in a crosslinking bath at a liquid temperature of 40 °C (an aqueous boric acid solution obtained by mixing 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (crosslinking treatment). Thereafter, while immersing the laminate in an aqueous boric acid solution (boric acid concentration: 4% by weight, potassium iodide concentration: 5% by weight) at a liquid temperature of 70°C, uniaxial stretching was performed in the longitudinal direction (lengthwise direction) between rolls with different peripheral speeds so that the total draw ratio became 5.5 times (stretching treatment in water). Thereafter, the laminate was immersed in a cleaning bath (an aqueous solution obtained by blending 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 20°C (cleaning treatment). Thereafter, while drying in an oven maintained at about 90°C, it was brought into contact with a SUS-made heating roll whose surface temperature was maintained at about 75°C (dry shrinkage treatment). In this way, a polarizer with a thickness of about 5 μm was formed on the resin substrate, and a laminate having a resin substrate / polarizer structure was obtained.

[0071] An HC-COP film (thickness: 27 μm) was laminated as a protective layer on the polarizer side of the obtained laminate 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-based resin (COP) film (thickness: 25 μm), and it was laminated so that the COP film was on the polarizer side. Next, the resin substrate was peeled off from the polarizer to obtain a polarizing plate having a structure of HC-COP film (protective layer) / polarizer.

[0072] (Production of the retardation layer) 10 g of a polymerizable liquid crystal (manufactured by BASF: trade name "Paliocolor LC242", represented by the following formula) showing a nematic liquid crystal phase and 3 g of a photopolymerization initiator (manufactured by BASF: trade name "Irgacure 907") for the polymerizable liquid crystal compound were dissolved in 40 g of toluene to prepare a liquid crystal composition (coating liquid).

Chemical formula

[0073] The surface of a polyethylene terephthalate (PET) film (thickness: 38 μm) was rubbed using a rubbing cloth to perform an alignment treatment. The direction of the alignment treatment was set to be 15° from the viewing side with respect to the absorption axis direction of the polarizer when laminating with the polarizer. The liquid crystal coating solution was applied to this aligned surface using a bar coater and heated and dried at 90 °C for 2 minutes to align the liquid crystal compound. Using a metal halide lamp, light of 1 mJ / cm 2 was irradiated onto the liquid crystal layer thus formed to cure the liquid crystal layer, thereby forming a liquid crystal alignment cured layer A (H layer) on the PET film. The thickness of the liquid crystal alignment cured layer A was 2.5 μm, and the in-plane retardation Re(550) was 270 nm. Furthermore, the liquid crystal alignment cured layer A exhibited refractive index characteristics of nx > ny = nz.

[0074] A liquid crystal alignment cured layer B (Q layer) was formed on the PET film in the same manner as above, except that the coating thickness was changed and the alignment treatment direction was set to be 75° from the viewing side with respect to the absorption axis direction of the polarizer. The thickness of the liquid crystal alignment cured layer B was 1.5 μm, and the in-plane retardation Re(550) was 140 nm. Furthermore, the liquid crystal alignment cured layer B exhibited refractive index characteristics of nx > ny = nz.

[0075] (Fabrication of laminate) The obtained liquid crystal alignment cured layer A (H layer) and liquid crystal alignment cured layer B (Q layer) were transferred in this order onto the polarizer side of the obtained polarizer. At this time, the transfer (lamination) was performed such that the angle formed by the absorption axis of the polarizer and the slow axis of the alignment cured layer A was 15°, and the angle formed by the absorption axis of the polarizer and the slow axis of the alignment cured layer B was 75°. The transfer of the liquid crystal alignment cured layer A (H layer) was performed via an ultraviolet curable adhesive (thickness: 0.5 μm). The transfer of the liquid crystal alignment cured layer B (Q layer) was performed via an ultraviolet curable adhesive (thickness: 1.5 μm). Thus, a laminate precursor was obtained. The transfer was performed while conveying in a roll. Furthermore, the transfer was performed in an environment where the water vapor amount was 9.3 g / m 3 (23 °C and 45% RH). The total thickness of the obtained laminate precursor was 36 μm, and the thickness ratio was 8.

[0076] The obtained long laminated body precursor was cut along a direction at 45° with respect to the longitudinal direction and the width direction (the direction perpendicular to the longitudinal direction) to obtain a sheet-like laminated body precursor of 165 mm × 80 mm. Note that the longitudinal direction corresponds to the absorption axis direction of the polarizer.

[0077] Next, a surface protection film (thickness 48 μm) was bonded to the protective layer side of the polarizing plate of the laminated body precursor. Note that the surface protection film is a film in which an adhesive layer (thickness 10 μm) is formed on a PET-based film (thickness 38 μm, moisture permeability 18 g / m 2 ·24 h). Furthermore, on the liquid crystal alignment curing layer B (Q layer) side of the laminated body precursor, (PET-based film, thickness 50 μm, moisture permeability 13 g / m 2 ·24 h) was bonded via an adhesive layer (thickness 15 μm) to obtain a sheet-like laminated body of 165 mm × 80 mm.

[0078] (Humidification treatment) The obtained sheet-like laminated body was placed in an environment of 23°C and 60% RH (water vapor amount 12.4 g / m 3 ) for 24 hours to correct the warp generated in the above-mentioned laminated body precursor.

[0079] [Example 2] In the production of the laminated body, except that a surface protection film with a thickness of 60 μm (a film in which an adhesive layer (thickness 10 μm) is formed on a PET-based film (thickness 50 μm, moisture permeability 13 g / m 2 ·24 h)) was bonded to the protective layer side of the polarizing plate of the laminated body precursor, a laminated body was obtained in the same manner as in Example 1.

[0080] [Example 3] In the production of the laminated body, a surface protection film with a thickness of 60 μm (a film in which an adhesive layer (thickness 10 μm) is formed on a PET-based film (thickness 50 μm, moisture permeability 13 g / m 2 ·24 h)) was bonded to the protective layer side of the polarizing plate of the laminated body precursor, and a separator (PET-based film, thickness 75 μm, moisture permeability 10 g / m2 A laminate was obtained in the same manner as in Example 1, except that it was bonded through an adhesive layer (thickness: 15 μm) for 24 hours.

[0081] [Example 4] In the production of the laminate, on the protective layer side of the polarizing plate of the laminate precursor, a surface protective film with a thickness of 85 μm (a film in which an adhesive layer (thickness: 10 μm) was formed on a PET-based film (thickness: 75 μm, water vapor transmission rate: 10 g / m 2 ·24 h)) was bonded, and on the liquid crystal alignment curing layer B (Q layer) side of the laminate precursor, a separator (PET-based film, thickness: 75 μm, water vapor transmission rate: 10 g / m 2 A laminate was obtained in the same manner as in Example 1, except that it was bonded through an adhesive layer (thickness: 15 μm) for 24 hours.

[0082] [Comparative Example 1] In the production of the laminate, on the liquid crystal alignment curing layer B (Q layer) side of the laminate precursor, a separator (PET-based film, thickness: 38 μm, water vapor transmission rate: 18 g / m 2 A laminate was obtained in the same manner as in Example 1, except that it was bonded through an adhesive layer (thickness: 15 μm) for 24 hours.

[0083] [Comparative Example 2] In the production of the laminate, on the liquid crystal alignment curing layer B (Q layer) side of the laminate precursor, a separator (PET-based film, thickness: 75 μm, water vapor transmission rate: 10 g / m 2 A laminate was obtained in the same manner as in Example 1, except that it was bonded through an adhesive layer (thickness: 15 μm) for 24 hours.

[0084] [Comparative Example 3] In the production of the laminate, on the protective layer side of the polarizing plate of the laminate precursor, a surface protective film with a thickness of 60 μm (a film in which an adhesive layer (thickness: 10 μm) was formed on a PET-based film (thickness: 50 μm, water vapor transmission rate: 13 g / m 2 ·24 h)) was bonded, and on the liquid crystal alignment curing layer B (Q layer) side of the laminate precursor, a separator (PET-based film, thickness: 38 μm, water vapor transmission rate: 18 g / m 2·24 h) was laminated in the same manner as in Example 1 except that it was laminated via an adhesive layer (thickness: 15 μm) to obtain a laminate.

[0085] [Comparative Example 4] In the production of the laminate, on the protective layer side of the polarizing plate of the laminate precursor, a surface protective film with a thickness of 85 μm (a film in which an adhesive layer (thickness: 10 μm) was formed on a PET-based film (thickness: 75 μm, moisture permeability: 10 g / m 2 ·24 h)) was laminated, and on the liquid crystal alignment curing layer B (Q layer) side of the laminate precursor, a separator (PET-based film, thickness: 38 μm, moisture permeability: 18 g / m 2 ·24 h) was laminated in the same manner as in Example 1 except that it was laminated via an adhesive layer (thickness: 15 μm) to obtain a laminate.

[0086] [Comparative Example 5] In the production of the laminate, on the protective layer side of the polarizing plate of the laminate precursor, a surface protective film with a thickness of 85 μm (a film in which an adhesive layer (thickness: 10 μm) was formed on a PET-based film (thickness: 75 μm, moisture permeability: 10 g / m 2 ·24 h)) was laminated, and on the liquid crystal alignment curing layer B (Q layer) side of the laminate precursor, a separator (PET-based film, thickness: 50 μm, moisture permeability: 13 g / m 2 ·24 h) was laminated in the same manner as in Example 1 except that it was laminated via an adhesive layer (thickness: 15 μm) to obtain a laminate.

[0087] <Evaluation> The laminates after the humidification treatment of each example and comparative example were stored in an environment of 23°C and 55% RH for 48 hours, and the change in warpage before and after storage was measured. Specifically, a test piece with a size of 140 mm × 70 mm was cut out from the laminate. At this time, it was cut out so that the absorption axis direction of the polarizer was the long side direction. On the plane, when the cut test piece was placed still with the separator side facing the plane side, the height of the highest part from the plane was measured to obtain the amount of warpage. Here, when the warpage was convex on the still surface side, it was defined as "positive (+)", and when it was convex on the side opposite to the still surface, it was defined as "negative (-)". Next, the difference between the amount of warpage of the laminate before storage and the amount of warpage of the laminate after storage was obtained. The evaluation results are summarized in Table 1 together with the center position of the polarizer. Note that the center position (%) of the polarizer in Table 1 is obtained by the formula: d÷(T / 2)×100 using the distance d between the center of the polarizer and the center of the laminate and the thickness T of the laminate shown in FIG. 4 in the thickness direction. Also, the change in warpage (mm) in Table 1 is the average value of 3 measurement samples.

Table 1

[0088] As is clear from Table 1, in the examples, the change in warpage is small. Specifically, the correction state of the warpage generated in the laminate precursor is well maintained.

Industrial Applicability

[0089] The retardation layer - attached polarizing plate according to one embodiment of the present invention is used as a retardation layer - attached polarizing plate for an image display device, and in particular, can be suitably used for a curved, or bendable, foldable, or rollable image display device. Representative examples of the image display device include a liquid crystal display device, an organic EL display device, and an inorganic EL display device.

Explanation of Signs

[0090] 10 Polarizing plate 11 Polarizer 11a Center of the polarizer 12 Protective layer 20 Retardation layer 21 First retardation layer (H layer) 22 Second retardation layer (Q layer) 31 First protective film 32 Second protective film 90 Precursor laminate 100 Laminate 100a Center of the laminate

Claims

1. A first protective film; a polarizing plate including a polarizer and a protective layer disposed on at least one side of the polarizer; A retardation layer; A laminate having, in this order, a first protective film, The sum of the thickness of the polarizing plate and the thickness of the retardation layer is 40 μm or less, the ratio of the thickness of the polarizing plate to the thickness of the retardation layer is 5 or more; The thickness of the second protective film is 50 μm or more, a center of the polarizer in a thickness direction is located within a range of 10% or less of half the thickness of the laminate from the center of the laminate in the thickness direction, a distance between the center of the polarizer in the thickness direction of the laminate and the center of the laminate is d (μm), and a thickness of the laminate is T (μm), a value calculated by the formula: d÷(T / 2)×100 is 10 or less. Laminate.

2. The laminate according to claim 1 , wherein the polarizing plate has a protective layer disposed only on a side of the polarizer on which the retardation layer is not disposed.

3. The laminate according to claim 1 or 2, wherein the retardation layer is a layer in which a liquid crystal compound is aligned and fixed.

4. The laminate according to claim 1 , wherein the first protective film has a thickness of 15 μm or more and 90 μm or less.

5. Providing a laminate according to any one of claims 1 to 4; and storing the laminate; The method for producing a polarizing plate with a retardation layer, comprising the steps of:

6. The method according to claim 5 , further comprising laminating the polarizing plate and the retardation layer to obtain a laminate precursor.

7. The method according to claim 6 , further comprising cutting the laminate precursor into sheets.

8. The method according to claim 5 , further comprising laminating the polarizing plate and the retardation layer with an active energy ray-curable adhesive.

9. The method according to claim 8 , wherein the active energy ray-curable adhesive has a thickness of 0.4 μm or more after curing.

10. The method according to claim 5 , further comprising subjecting the laminate to a humidification treatment before the storage.

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