Polarizing plate with adhesive layer, and display device

Abstract

This invention provides a polarizing plate with an adhesive layer and a display device in which the occurrence of curling is suppressed. This polarizing plate with an adhesive layer comprises: a polarizing plate having a protective film, a polarizer, a positive A plate, and a positive C plate in the stated order; and an adhesive layer disposed on the positive C plate side of the polarizing plate. The positive A plate is a layer obtained by curing a polymerizable liquid crystal compound, and the thickness of the positive C plate is 20.0-70.0 μm.

Description

Polarizing plate with adhesive layer, display device

[0001] The present invention relates to a polarizing plate with a pressure-sensitive adhesive layer and a display device.

[0002] Optically anisotropic layers formed using liquid crystal compounds are used in various fields such as displays. For example, Patent Document 1 discloses a method for producing a polarizing plate including a polarizer and an optically anisotropic layer.

[0003] International Publication No. 2023 / 276611

[0004] As one use form of a polarizing plate, it is desirable to use it as a polarizing plate with a pressure-sensitive adhesive layer by disposing a pressure-sensitive adhesive layer on one surface of the polarizing plate. The present inventors have fabricated a polarizing plate with a pressure-sensitive adhesive layer by disposing a pressure-sensitive adhesive layer on one surface of a polarizing plate as disclosed in Patent Document 1, but have found that the polarizing plate with the pressure-sensitive adhesive layer curls, making it difficult to attach to an object to be attached.

[0005] In view of the above circumstances, an object of the present invention is to provide a polarizing plate with a pressure-sensitive adhesive layer, in which curling is suppressed. Another object of the present invention is to provide a display device.

[0006] The present inventors have found that the above problems can be solved by the following configuration.

[0007] (1) A polarizing plate with an adhesive layer, the polarizing plate having a protective film, a polarizer, a positive A plate, and a positive C plate in this order, and an adhesive layer disposed on the positive C plate side of the polarizing plate, wherein the positive A plate is a layer obtained by curing a polymerizable liquid crystal compound, and the positive C plate has a thickness of 20.0 to 70.0 μm. (2) The polarizing plate with an adhesive layer according to (1), in which the polarizing plate with an adhesive layer is bonded to a glass substrate via an adhesive, and when a cross-cut test with 100 squares is performed on the bonded polarizing plate with an adhesive layer, 50 or fewer squares peel off. (3) The polarizing plate with an adhesive layer according to (1) or (2), in which the positive C plate has a retardation in the thickness direction of −100 to −30 nm at a wavelength of 550 nm. (4) The polarizing plate with an adhesive layer according to any one of (1) to (3), in which the positive C plate includes a polymer film. (5) The polarizing plate with a pressure-sensitive adhesive layer according to (4), wherein the polymer film is a cellulose acylate film. (6) The polarizing plate with a pressure-sensitive adhesive layer according to (4) or (5), wherein the polymer film has an in-plane retardation of 10 nm or less at a wavelength of 550 nm. (7) The polarizing plate with a pressure-sensitive adhesive layer according to any one of (4) to (6), wherein the polymer film has a retardation in the thickness direction of −100 to 30 nm at a wavelength of 550 nm. (8) The polarizing plate with a pressure-sensitive adhesive layer according to any one of (4) to (7), wherein the positive C plate comprises a vertically aligned liquid crystal layer and a polymer film. (9) The polarizing plate with a pressure-sensitive adhesive layer according to (8), wherein the vertically aligned liquid crystal layer comprises a crosslinked material that is unevenly distributed on the polymer film side. (10) The polarizing plate with a pressure-sensitive adhesive layer according to (8) or (9), wherein the vertically aligned liquid crystal layer is a layer formed using a composition containing a liquid crystal compound and a crosslinkable polymer, and the crosslinkable polymer has a hydroxyl group. (11) The polarizing plate with a pressure-sensitive adhesive layer according to any one of (8) to (10), wherein the vertically aligned liquid crystal layer contains a photoisomerizable compound on the surface opposite to the polymer film side.(12) The polarizing plate with a pressure-sensitive adhesive layer according to any one of (1) to (11), wherein the angle between the absorption axis of the polarizer and the in-plane slow axis of the positive A plate is 45±10°, and the in-plane retardation of the positive A plate at a wavelength of 550 nm is 120 to 170 nm. (13) The polarizing plate with a pressure-sensitive adhesive layer according to any one of (1) to (12), wherein the polarizer and the positive A plate are laminated via a polyvinyl alcohol-based adhesive. (14) The polarizing plate with a pressure-sensitive adhesive layer according to any one of (1) to (13), wherein the positive A plate is a layer obtained by curing a composition containing a polymerizable liquid crystal compound and a polymer having a group represented by formula (1) described below. (15) The polarizing plate with a pressure-sensitive adhesive layer according to any one of (1) to (12), wherein the polarizer and the positive A plate are laminated via an adhesive layer obtained by curing an ultraviolet-curable adhesive. (16) The polarizing plate with a pressure-sensitive adhesive layer according to any one of (8) to (11), wherein the polymer film includes a region A containing a component derived from a liquid crystal compound contained in the vertically aligned liquid crystal layer, and the thickness of the region A is 20 to 200 nm. (17) A display device having the polarizing plate with a pressure-sensitive adhesive layer according to any one of (1) to (16).

[0008] According to the present invention, a polarizing plate with a pressure-sensitive adhesive layer, in which curling is suppressed, can be provided. Further, according to the present invention, a display device can also be provided.

[0009] 1 is a diagram conceptually illustrating an example of a pressure-sensitive adhesive layer-attached polarizing plate of the present invention.

[0010] The present invention will be described in detail below. The following description of the constituent elements may be based on representative embodiments and specific examples, but the present invention is not limited to such embodiments. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0011] In this specification, the term "absorption axis" refers to the polarization direction in which the absorbance is maximized in the plane when linearly polarized light is incident, and the term "in-plane slow axis" refers to the direction in which the refractive index is maximized in the plane.

[0012] In this specification, Re(λ) and Rth(λ) represent the in-plane retardation and the thickness retardation, respectively, at a wavelength λ. Unless otherwise specified, the wavelength λ is 550 nm. In the present invention, Re(λ) and Rth(λ) are values ​​measured at a wavelength λ using an AxoScan (manufactured by Axometrics). By inputting the average refractive index ((nx + ny + nz) / 3) and film thickness (d) into AxoScan, the following in-plane slow axis direction (°) is calculated: Re(λ) = R0(λ) Rth(λ) = ((nx + ny) / 2 - nz) × d. Note that R0(λ) is displayed as a numerical value calculated by AxoScan, but it means Re(λ).

[0013] In this specification, the refractive indices nx, ny, and nz are measured using an Abbe refractometer (NAR-4T, manufactured by Atago Co., Ltd.) with a sodium lamp (λ = 589 nm) as a light source. When measuring wavelength dependency, measurements can be made using a multi-wavelength Abbe refractometer DR-M2 (manufactured by Atago Co., Ltd.) in combination with an interference filter. Values ​​from the Polymer Handbook (John Wiley & Sons, Inc.) and catalogs of various optical films can also be used. Examples of average refractive index values ​​for major optical films are listed below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).

[0014] In this specification, A plates and C plates are defined as follows. There are two types of A plates: positive A plates (positive A plates) and negative A plates (negative A plates). When the refractive index in the in-plane slow axis direction of the film (the direction in which the in-plane refractive index is maximum) is nx, the refractive index in the direction perpendicular to the in-plane slow axis is ny, and the refractive index in the thickness direction is nz, the positive A plates satisfy the relationship of formula (A1), and the negative A plates satisfy the relationship of formula (A2). Note that the positive A plates have a positive Rth, and the negative A plates have a negative Rth. Formula (A1) nx>ny≒nz Formula (A2) ny<nx≒nz Note that the above "≒" encompasses not only the case where the two are completely identical, but also the case where the two are substantially identical. "Substantially the same" means, for example, that "ny ≒ nz" also includes cases where (ny - nz) x d (where d is the film thickness) is -10 to 10 nm, preferably -5 to 5 nm, and "nx ≒ nz" also includes cases where (nx - nz) x d is -10 to 10 nm, preferably -5 to 5 nm. There are two types of C plates: positive C plates (positive C plates) and negative C plates (negative C plates). Positive C plates satisfy the relationship of formula (C1), while negative C plates satisfy the relationship of formula (C2). Note that positive C plates have a negative Rth value, and negative C plates have a positive Rth value. Formula (C1) nz > nx ≒ ny Formula (C2) nz < nx ≒ ny Note that the above "≒" includes not only cases where the two are completely identical, but also cases where the two are substantially identical. The term "substantially the same" includes, for example, the case where (nx-ny) x d (where d is the thickness of the film) is 0 to 10 nm, preferably 0 to 5 nm, in "nx≈ny".

[0015] A characteristic feature of the pressure-sensitive adhesive layer-attached polarizing plate of the present invention is that it uses a positive C plate of a predetermined thickness. One factor that makes conventional pressure-sensitive adhesive layer-attached polarizing plates prone to curling is that the positive A plate included in the pressure-sensitive adhesive layer-attached polarizing plate is a layer obtained by curing a polymerizable liquid crystal compound. Because the positive A plate is a layer obtained by curing a polymerizable liquid crystal compound, stress due to cure shrinkage during polymerization remains, which is thought to result in the entire pressure-sensitive adhesive layer-attached polarizing plate being prone to curling. Therefore, in the present invention, curling is suppressed by adjusting the thickness of the positive C plate to a predetermined range.

[0016] FIG. 1 shows an example of a polarizing plate with a pressure-sensitive adhesive layer of the present invention. As shown in FIG. 1, the polarizing plate with a pressure-sensitive adhesive layer 10 includes a polarizing plate 12 and a pressure-sensitive adhesive layer 22, in this order. The polarizing plate 12 includes a protective film 14, a polarizer 16, a positive A plate 18, and a positive C plate 20, in this order. As shown in FIG. 1, the pressure-sensitive adhesive layer 22 is disposed on the positive C plate 20 side of the polarizing plate 12. More specifically, the pressure-sensitive adhesive layer 22 is disposed on the surface of the polarizing plate 12 facing the positive C plate 20. The positive C plate 20 also includes a vertically aligned liquid crystal layer 24 and a polymer film 26. In FIG. 1, each layer is directly adjacent to the other layer, but as described below, the layers may be laminated via another layer (e.g., an adhesive layer). Below, each component included in the polarizing plate with a pressure-sensitive adhesive layer 10 is described in detail.

[0017] <Protective Film> The protective film is a film that protects a polarizer. The configuration of the protective film is not particularly limited, and may be, for example, a transparent support or a hard coat layer, or a laminate of a transparent support and a hard coat layer. In this specification, "transparent" means that the visible light transmittance is 60% or more, preferably 80% or more, and more preferably 90% or more. The upper limit is not particularly limited, but is often less than 100%.

[0018] The transparent support may be a known transparent support (preferably a transparent resin support). Materials for forming the transparent support include, for example, cellulose-based resins (hereinafter also referred to as cellulose acylate) typified by triacetyl cellulose, norbornene-based resins (such as Zeonex and Zeonor manufactured by Nippon Zeon Co., Ltd., and Arton manufactured by JSR Corporation), acrylic resins, polyester resins, and polystyrene resins. Among these, cellulose-based resins or norbornene-based resins are preferred, and cellulose-based resins are more preferred. The norbornene-based resin refers to a resin having a norbornene skeleton. More specifically, cycloolefin polymers (COP) and cycloolefin copolymers (COC) are examples. Furthermore, known layers can be used as the hard coat layer, and may be, for example, a layer obtained by polymerizing and curing a polyfunctional monomer.

[0019] The thickness of the protective film is not particularly limited, but is preferably 40 μm or less, more preferably 25 μm or less, from the viewpoint of making it possible to reduce the thickness of the polarizing plate. The lower limit is not particularly limited, but is often 10 μm or more.

[0020] <Polarizer> The polarizer may be any member capable of converting natural light into specific linearly polarized light, and may be, for example, an absorption polarizer. The type of polarizer is not particularly limited, and commonly used polarizers may be used, such as iodine-based polarizers, dye-based polarizers using dichroic materials, and polyene-based polarizers. Iodine-based polarizers and dye-based polarizers are generally produced by adsorbing iodine or a dichroic dye into polyvinyl alcohol and stretching the resulting material.

[0021] The polarizer is also preferably a polarizer formed using a composition containing a dichroic material and a liquid crystal compound having a polymerizable group. The dichroic material is not particularly limited, and examples thereof include visible light absorbing materials (dichroic dyes), luminescent materials (fluorescent materials, phosphorescent materials), ultraviolet absorbing materials, infrared absorbing materials, nonlinear optical materials, carbon nanotubes, and inorganic materials (e.g., quantum rods), and any conventionally known dichroic material (dichroic dye) can be used.

[0022] The luminosity-corrected single transmittance of the polarizer is not particularly limited, and is preferably 42% or more, and more preferably 43% or more, in terms of providing better effects of the present invention. The upper limit is not particularly limited, and is preferably 48% or less. The luminosity-corrected single transmittance is calculated by the following method. For a polarizer, the transmittance (T1) in the absorption axis direction and the transmittance (T2) in the direction perpendicular to the absorption axis are measured in the wavelength range of 380 to 780 nm using a spectrophotometer equipped with an integrating sphere ("V7100" manufactured by JASCO Corporation), and the single transmittance at each wavelength is calculated based on the following formula: Single transmittance (%) = (T1 + T2) / 2. The obtained single transmittance is subjected to luminosity correction using a 2-degree visual field (illuminant C) according to JIS Z 8701:1999 "Method of representing color - XYZ color system and X10Y10Z10 color system," to determine the luminosity-corrected single transmittance.

[0023] The thickness of the polarizer is not particularly limited, but is preferably 40 μm or less, more preferably 25 μm or less, from the viewpoint of making it possible to reduce the thickness of the polarizing plate. The lower limit is not particularly limited, but is often 5 μm or more.

[0024] <Positive A Plate> The positive A plate is defined as described above. Re(550), which is the in-plane retardation of the positive A plate at a wavelength of 550 nm, is not particularly limited, but is preferably 100 to 180 nm, more preferably 120 to 170 nm, and even more preferably 130 to 150 nm, in order to provide a polarizing plate of the present invention with superior properties as a circular polarizing plate.

[0025] The positive A plate may exhibit either forward wavelength dispersion (a property in which the in-plane retardation decreases as the measurement wavelength increases) or reverse wavelength dispersion (a property in which the in-plane retardation increases as the measurement wavelength increases). Note that the forward wavelength dispersion and reverse wavelength dispersion are preferably exhibited in the visible light region.

[0026] The positive A plate is a layer obtained by curing a polymerizable liquid crystal compound. Among these, a layer obtained by curing a horizontally aligned polymerizable rod-shaped liquid crystal compound is preferred, as the polarizing plate of the present invention is superior as a circular polarizing plate. The state in which the polymerizable rod-shaped liquid crystal compound is horizontally aligned means that the long axis of the polymerizable rod-shaped liquid crystal compound is parallel to the main surface of the positive A plate. Strict parallelism is not required, and the angle between the long axis of the polymerizable rod-shaped liquid crystal compound and the main surface of the positive A plate is preferably in the range of 0±20°, more preferably 0±10°.

[0027] A polymerizable liquid crystal compound is a liquid crystal compound having a polymerizable group. Known compounds can be used as the polymerizable liquid crystal compound. Examples of polymerizable rod-shaped liquid crystal compounds include the compounds described in claim 1 of JP-A-11-513019 and paragraphs 0026 to 0098 of JP-A-2005-289980. In this specification, the type of polymerizable group is not particularly limited, and a functional group capable of undergoing an addition polymerization reaction is preferred, a polymerizable ethylenically unsaturated group or a ring-polymerizable group is more preferred, and a (meth)acryloyl group, a vinyl group, a styryl group, or an allyl group is even more preferred.

[0028] The positive A plate is preferably a layer formed by fixing a polymerizable rod-shaped liquid crystal compound by polymerization, and more preferably a layer formed by fixing a horizontally aligned polymerizable rod-shaped liquid crystal compound by polymerization. In this specification, the "fixed" state refers to a state in which the alignment of the liquid crystal compound is maintained. Specifically, it is preferred that the layer has no fluidity and can stably maintain the fixed alignment state without causing any change in the alignment state due to an external field or external force, usually within a temperature range of 0 to 50°C, or under more severe conditions within a temperature range of -30 to 70°C.

[0029] The angle between the in-plane slow axis of the positive A plate and the absorption axis of the polarizer is not particularly limited, but is preferably within the range of 45±10° (35 to 55°) in order to provide the polarizing plate of the present invention with superior properties as a circular polarizing plate.

[0030] The thickness of the positive A plate is not particularly limited, but is preferably 10 μm or less, and more preferably 0.1 to 5.0 μm. The thickness of the positive A plate refers to the average thickness of the positive A plate. The average thickness is determined by measuring the thickness at any five or more points on the positive A plate and calculating the arithmetic average. The thickness can be measured using, for example, a reflection spectroscopic film thickness meter FE3000.

[0031] The positive A plate is preferably a layer obtained by curing a composition containing a polymerizable liquid crystal compound and a polymer having a group represented by formula (1). The polymerizable liquid crystal compound is as described above.

[0032] By using a polymer having a group represented by formula (1), the adhesion between the positive A plate and the PVA adhesive disposed adjacent to the positive A plate is improved. ｘ１ ) ２ R ｘ１ each independently represents a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group, and two R ｘ１ may be linked to each other via an alkylene linking group, an arylene linking group, or a linking group consisting of a combination thereof.

[0033] Examples of the substituted or unsubstituted aliphatic hydrocarbon group include an alkyl group, an alkenyl group, or an alkynyl group, each of which may have a substituent. Examples of the substituted or unsubstituted aryl group include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, an indenyl group, an acenabutenyl group, a fluorenyl group, and a pyrenyl group. Examples of the substituted or unsubstituted heteroaryl group include a heteroaryl group obtained by removing one hydrogen atom from a heteroaromatic ring containing one or more heteroatoms selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom.

[0034] The polymer preferably contains a repeating unit having a group represented by formula (1). Examples of the repeating unit having a group represented by formula (1) include a repeating unit represented by formula (X).

[0035]

[0036] R ｘ１ The definition of R is as described above. ｘ２ and R ｘ３ each independently represents a hydrogen atom or an alkyl group. The number of carbon atoms in the alkyl group is not particularly limited, and is preferably 1 to 18. The alkyl group may have any of a linear, branched, or cyclic structure.

[0037] R ｘ４ represents a hydrogen atom or a substituent, such as a hydroxy group, an alkyl group, an alkenyl group, or an aryl group.

[0038] L ｘ represents a divalent linking group. The divalent linking group is not particularly limited, but may be an alkylene group (preferably an alkylene group having 1 to 20 carbon atoms), an arylene group, —O—, —S—, —CO—, —SO—, or —SO ２ -, -NR ａ -, or a divalent linking group that is a combination of two or more of these. ａ represents a hydrogen atom or an alkyl group. Among them, the divalent linking group is -alkylene group -O- (arylene group -CO-O) ｎｘ -an arylene group- is preferred. nx represents an integer of 0 to 2.

[0039] The content of the repeating unit having the group represented by formula (1) is preferably 5 to 30% by mass based on the total repeating units contained in the polymer.

[0040] The polymer may contain a repeating unit other than the repeating unit having the group represented by formula (1). For example, the polymer may contain a repeating unit having a group represented by formula (2).

[0041]

[0042] Rｙ１ ~R ｙ３ each independently represents an alkyl group, an alkenyl group, an aryl group, or an alkylenearyl group. Examples of alkyl groups include linear alkyl groups having 1 to 18 carbon atoms, branched alkyl groups having 3 to 18 carbon atoms, and cyclic alkyl groups. Examples of alkenyl groups include alkenyl groups having 2 to 12 carbon atoms. Examples of aryl groups include aryl groups having 6 to 12 carbon atoms. Specific examples include phenyl groups, α-methylphenyl groups, and naphthyl groups. Examples of alkylenearyl groups include alkylenearyl groups having 7 to 30 carbon atoms.

[0043] The polymer preferably contains a repeating unit having a group represented by formula (2). Examples of the repeating unit having a group represented by formula (2) include a repeating unit represented by formula (Y).

[0044]

[0045] R ｙ１ ~R ｙ３ The definition of R is as described above. ｙ４ and R ｙ５ each independently represents an alkyl group. The number of carbon atoms in the alkyl group is not particularly limited, and is preferably 1 to 18. The alkyl group may have any of a linear, branched, or cyclic structure.

[0046] R ｙ６ represents a hydrogen atom or a substituent, such as a hydroxy group, an alkyl group, an alkenyl group, or an aryl group.

[0047] L ｙ１ represents a single bond or an alkylene group having 1 to 6 carbon atoms; ｙ２ represents a ny+1-valent linking group that does not have a fluorine atom. ｙ２ The ny+1-valent linking group having no fluorine atom represented by the formula (1) is preferably, for example, a ny+1-valent hydrocarbon group having 1 to 15 carbon atoms which may have a substituent other than a fluorine atom, and in which some of the carbon atoms constituting the hydrocarbon group may be substituted with heteroatoms. For example, —CH２ -, one or two or more non-adjacent -CH ２ Each - may be independently substituted with -O-, -CO-, -S-, or -N(Q)-. Q represents a hydrogen atom or a substituent, and the substituent represented by Q is preferably an alkyl group, more preferably a linear alkyl group having 1 to 4 carbon atoms, and even more preferably a methyl group or an ethyl group. Furthermore, >C< (carbon atom) may be substituted with >Si< (silicon atom).

[0048] ny represents an integer of 2 or greater. ny is preferably an integer of 2 to 8, more preferably an integer of 3 to 6, and even more preferably an integer of 3 to 5.

[0049] The content of the repeating unit having the group represented by formula (2) is preferably 25 to 65% by mass based on the total repeating units contained in the polymer.

[0050] The polymer preferably contains a repeating unit having a polymerizable group. The polymerizable group is as described above. An example of the repeating unit having a polymerizable group is a repeating unit represented by formula (Z).

[0051]

[0052] R ｚ１ and R ｚ２ each independently represents a hydrogen atom or an alkyl group. The number of carbon atoms in the alkyl group is not particularly limited, and is preferably 1 to 18. The alkyl group may have any of a linear, branched, or cyclic structure.

[0053] R ｚ３ represents a hydrogen atom or a substituent, such as a hydroxy group, an alkyl group, an alkenyl group, or an aryl group.

[0054] L ｚ represents a divalent linking group. The divalent linking group is not particularly limited, but may be an alkylene group (preferably an alkylene group having 1 to 20 carbon atoms), an arylene group, —O—, —S—, —CO—, —SO—, or —SO ２ -, -NR ａ-, or a divalent linking group that is a combination of two or more of these. ａ represents a hydrogen atom or an alkyl group.

[0055] R ｚ４ represents a polymerizable group.

[0056] The content of the repeating unit having a polymerizable group is preferably 5 to 40% by mass based on the total repeating units contained in the polymer.

[0057] The weight average molecular weight of the polymer having a group represented by formula (1) is preferably 5,000 to 200,000.

[0058] The content of the polymerizable liquid crystal compound in the composition is not particularly limited, but is preferably 50 to 99.9% by mass, more preferably 80 to 99% by mass, based on the total solid content of the composition. The content of the polymer in the composition is not particularly limited, but is preferably 0.001 to 5.0% by mass, more preferably 0.01 to 2.0% by mass, based on the total solid content of the composition. The solid content refers to the components in the composition excluding the solvent. Note that even if the composition is in a liquid state, it is considered to be the solid content.

[0059] <Positive C Plate> The positive C plate is defined as described above. Rth(550), which is the retardation in the thickness direction at a wavelength of 550 nm of the positive C plate, is not particularly limited, but is preferably −120 to −10 nm, more preferably −100 to −30 nm, in order to provide the polarizing plate of the present invention with a superior function as a circular polarizing plate.

[0060] The configuration of the positive C plate is not particularly limited, and examples include a vertically aligned liquid crystal layer (a layer formed by fixing vertically aligned rod-shaped liquid crystal compounds) and a polymer film. A laminate of a vertically aligned liquid crystal layer and a polymer film is preferred, as it provides better effects of the present invention. That is, the positive C plate preferably includes a vertically aligned liquid crystal layer and a polymer film. When the positive C plate includes a vertically aligned liquid crystal layer and a polymer film, it may further include an optically isotropic layer (e.g., a pressure-sensitive adhesive layer) between the vertically aligned liquid crystal layer and the polymer film. The optically isotropic layer refers to a layer having an in-plane retardation Re of 10 nm or less at a wavelength of 550 nm and an absolute value of the thickness-direction retardation Rth of 10 nm or less at a wavelength of 550 nm. As described above, when the positive C plate includes an optically isotropic layer between the vertically aligned liquid crystal layer and the polymer film, the thickness of the optically isotropic layer is also included in the thickness of the positive C plate. Furthermore, in terms of better adhesion between the vertically aligned liquid crystal layer and the polymer film, it is preferred that the vertically aligned liquid crystal layer and the polymer film be in direct contact. The state in which the rod-shaped liquid crystal compounds are vertically aligned means that the long axes of the rod-shaped liquid crystal compounds are parallel to the thickness direction of the positive C plate. Strict parallelism is not required, and the angle between the long axes of the rod-shaped liquid crystal compounds and the thickness direction of the first positive C plate is preferably in the range of 0±20°, more preferably 0±10°. The vertically aligned liquid crystal layer is preferably a layer formed by fixing vertically aligned polymerizable rod-shaped liquid crystal compounds by polymerization.

[0061] When the vertically aligned liquid crystal layer of the positive C plate is in direct contact with the polymer film, the polymer film preferably includes a region (referred to as region A) containing a component derived from the liquid crystal compound contained in the vertically aligned liquid crystal layer. From the viewpoints of adhesion and alignment with the vertically aligned liquid crystal layer, the thickness of region A is preferably 20 to 200 nm. A vertically aligned liquid crystal compound is preferably present in region A. Methods for controlling the thickness of region A include a method of controlling the thickness of region A by adjusting the type of solvent or solids concentration contained in a composition for forming a vertically aligned liquid crystal layer, a method of controlling the thickness of region A by incorporating a crosslinkable polymer or vertical alignment agent described below into the vertically aligned liquid crystal layer, and a method of controlling the thickness of region A by adjusting the drying conditions or heating conditions of the vertically aligned liquid crystal layer. Whether or not a polymer film contains a region A containing components derived from the liquid crystal compound contained in the vertically aligned liquid crystal layer can be confirmed by measuring the secondary ion intensity of the components derived from the liquid crystal compound of the vertically aligned liquid crystal layer by time-of-flight secondary ion mass spectrometry while irradiating an ion beam from the surface on the vertically aligned liquid crystal layer side toward the polymer film side of the vertically aligned liquid crystal layer, and checking whether the secondary ion intensity I of the components derived from the liquid crystal compound of the vertically aligned liquid crystal layer in the polymer film satisfies the following formula (I-1) and whether or not there is a thickness of a region including the surface on the vertically aligned liquid crystal layer side of the polymer film. In the formula, Ic represents the average value of the secondary ion intensity of the components derived from the liquid crystal compound of the vertically aligned liquid crystal layer in the central region from the surface on the polymer film side of the vertically aligned liquid crystal layer to a depth position corresponding to 40% to 60% of the total thickness of the vertically aligned liquid crystal layer. 0.05≦I / Ic (I-1)

[0062] Known compounds can be used as the rod-shaped liquid crystal compound, including, for example, the rod-shaped liquid crystal compounds exemplified for the positive A plate.

[0063] The liquid crystal compound (preferably a rod-shaped liquid crystal compound) may have a polymerizable group. The types of polymerizable groups that the liquid crystal compound may have are as described above.

[0064] The thickness of the positive C plate is 20.0 to 70.0 μm, preferably 25.0 to 60.0 μm, and more preferably 30.0 to 50.0 μm, in terms of further suppressing curling. The thickness of the positive C plate refers to the average thickness of the positive C plate. The average thickness is determined by measuring the thickness at any five or more points on the positive C plate and calculating the arithmetic average. The thickness can be measured using, for example, a reflection spectroscopic film thickness meter FE3000.

[0065] One preferred embodiment of the positive C-plate is one that includes a polymer film, and more preferably one that includes a vertically aligned liquid crystal layer and a polymer film. The resin constituting the polymer film is not particularly limited, and known resins can be used. More specifically, examples of the resin include cellulose-based resins (hereinafter also referred to as cellulose acylate) typified by triacetyl cellulose, norbornene-based resins (such as Zeonex and Zeonor manufactured by Nippon Zeon Co., Ltd., and Arton manufactured by JSR Corporation), acrylic resins, polyester-based resins, and polystyrene-based resins. Among these, the polymer film is preferably a film containing a cellulose-based resin, and more preferably a cellulose acylate film.

[0066] The retardation in the thickness direction of the polymer film at a wavelength of 550 nm is not particularly limited, and is preferably −120 to 30 nm, more preferably −100 to 30 nm, in order to provide a superior circular polarizing plate. The in-plane retardation of the polymer film at a wavelength of 550 nm is not particularly limited, and is preferably 10 nm or less, in order to provide a superior circular polarizing plate. The lower limit is not particularly limited, and is 0 nm.

[0067] The thickness of the polymer film is not particularly limited, but is preferably 15.0 to 65.0 μm, more preferably 25.0 to 60.0 μm, and particularly preferably 30.0 to 50.0 μm, in order to further suppress the occurrence of curling. The thickness of the polymer film refers to the average thickness of the polymer film. The average thickness is determined by measuring the thickness at any five or more points on the polymer film and calculating the arithmetic average.

[0068] As described above, the vertically aligned liquid crystal layer is a layer formed by fixing vertically aligned rod-shaped liquid crystal compounds. When the positive C plate includes a vertically aligned liquid crystal layer and a polymer film, the vertically aligned liquid crystal layer preferably includes a crosslinked material that is unevenly distributed on the polymer film side, in order to improve adhesion between the vertically aligned liquid crystal layer and the polymer film. Examples of the crosslinked material include crosslinked materials formed by crosslinking a polymer having a crosslinkable group, as described below. Examples of the crosslinkable group include the polymerizable group described above. Note that the crosslinked material being unevenly distributed on the polymer film side means that when the vertically aligned liquid crystal layer is divided into two along the thickness direction, the content of the crosslinked material in the divided region on the polymer film side is greater than the content of the crosslinked material in the divided region opposite the polymer film side.

[0069] One preferred embodiment of the vertically aligned liquid crystal layer is a layer formed using a composition containing a liquid crystal compound and a crosslinkable polymer, and the crosslinkable polymer has a hydroxyl group. When the crosslinkable polymer has a hydroxyl group, the polymer having the crosslinkable group tends to be unevenly distributed on the polymer film (particularly, cellulose acylate film) side, and as a result, the crosslinked product obtained by crosslinking the crosslinkable polymer tends to be unevenly distributed on the polymer film side as described above. Examples of the liquid crystal compound contained in the composition include the liquid crystal compounds described above.

[0070] The crosslinkable polymer preferably contains a repeating unit having a crosslinkable group. As the crosslinkable group, a polymerizable group is preferred as described above. That is, the crosslinkable polymer preferably contains a repeating unit having a polymerizable group. Examples of the repeating unit having a polymerizable group include the repeating unit represented by the above-described formula (Z).

[0071] In order to localize the crosslinked product on the polymer film side, the crosslinkable polymer preferably does not contain any of fluorine atoms, silicon atoms, and photoalignable groups (e.g., cinnamoyl groups or azo groups). That is, the crosslinked product obtained by crosslinking the crosslinkable polymer preferably does not contain any of fluorine atoms, silicon atoms, and photoalignable groups.

[0072] The content of the repeating unit having a crosslinkable group is preferably 50 to 99% by mass based on the total repeating units contained in the crosslinkable polymer.

[0073] The crosslinkable polymer preferably contains a repeating unit having a hydroxyl group. The number of hydroxyl groups contained in the repeating unit is not particularly limited, and is preferably 1 to 3, and more preferably 1 or 2. The content of the repeating unit having a hydroxyl group is preferably 1 to 30 mass% based on the total repeating units contained in the crosslinkable polymer.

[0074] The crosslinkable polymer may have a repeating unit other than the repeating unit described above. The content of the other repeating unit is preferably 1 to 30% by mass based on the total repeating units contained in the crosslinkable polymer.

[0075] The weight average molecular weight of the crosslinkable polymer is preferably 5,000 to 200,000.

[0076] Specific examples of crosslinkable polymers include, but are not limited to, the following structures: a to c described in the repeating units represent the content (% by mass) of each repeating unit relative to all repeating units.

[0077]

[0078] The content of the liquid crystal compound in the composition is not particularly limited, but is preferably 50 to 99% by mass, more preferably 80 to 95% by mass, based on the total solid content of the composition. The content of the crosslinkable polymer in the composition is not particularly limited, but is preferably 0.1 to 20% by mass, more preferably 1 to 5% by mass, based on the total solid content of the composition. The solid content refers to the components in the composition excluding the solvent. Note that even if the composition is in a liquid state, it is considered to be the solid content.

[0079] The vertically aligned liquid crystal layer preferably contains an alignment control agent. The alignment control agent may be any known material as long as it has the function of vertically aligning the liquid crystal layer. When the composition for forming the vertically aligned liquid crystal layer contains the above-mentioned hydroxyl group-containing crosslinkable polymer, it is preferable to use an onium salt compound as the alignment control agent, as this will result in higher alignment.

[0080] The vertically aligned liquid crystal layer preferably contains a photoisomerizable compound on the surface opposite to the polymer film side. As described below, by including a photoisomerizable compound in the vertically aligned liquid crystal layer, a positive A plate can be formed directly on the vertically aligned liquid crystal layer, thereby improving the adhesion between the vertically aligned liquid crystal layer and the positive A plate. The photoisomerizable compound is not particularly limited as long as it is a photoisomerizable compound, but examples include compounds having a photoisomerizable group. Examples of photoisomerizable groups include a cinnamoyl group, a chalcone group, an azobenzene group, and a stilbene group. The photoisomerizable compound preferably contains a repeating unit having a photoisomerizable group. The content of the repeating unit having a photoisomerizable group is preferably 5 to 45% by mass of all repeating units contained in the photoisomerizable compound.

[0081] The photoisomerizable compound preferably contains the repeating unit having the group represented by formula (2) described above. The content of the repeating unit having the group represented by formula (2) is preferably 20 to 60 mass % based on the total repeating units contained in the photoisomerizable compound.

[0082] The thickness of the vertically aligned liquid crystal layer is not particularly limited, but is preferably 10 μm or less, more preferably 0.1 to 5.0 μm, in order to further suppress the occurrence of curl. The thickness of the vertically aligned liquid crystal layer refers to the average thickness of the vertically aligned liquid crystal layer. The average thickness is determined by measuring the thickness at any five or more points of the vertically aligned liquid crystal layer and calculating the arithmetic average. The thickness can be measured, for example, using a reflection spectroscopic film thickness meter FE3000.

[0083] When the vertically aligned liquid crystal layer and the positive A plate are in direct contact with each other, from the viewpoint of adhesion, it is preferable that the vertically aligned liquid crystal layer contains a region (referred to as region B) containing a component derived from the liquid crystal compound contained in the positive A plate. The thickness of region B is preferably 5 to 100 nm. The method for measuring region B can be the same as that for region A.

[0084] <Adhesive Layer> The adhesive layer is a layer formed using an adhesive. Examples of adhesives include rubber-based adhesives, acrylic-based adhesives, silicone-based adhesives, urethane-based adhesives, vinyl alkyl ether-based adhesives, polyvinyl alcohol-based adhesives, polyvinylpyrrolidone-based adhesives, polyacrylamide-based adhesives, and cellulose-based adhesives, and acrylic-based adhesives or polyvinyl alcohol-based adhesives (PVA adhesives) are preferred. As the acrylic adhesive, a copolymer of (meth)acrylate in which the alkyl group in the ester moiety has 20 or less carbon atoms, such as a methyl group, an ethyl group, or a butyl group, and a (meth)acrylic monomer having a functional group, such as (meth)acrylic acid or hydroxyethyl (meth)acrylate, is preferred.

[0085] The thickness of the pressure-sensitive adhesive layer is not particularly limited, and the lower limit of the thickness is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 15 μm or more.The upper limit of the thickness is preferably 45 μm or less, more preferably 30 μm or less, and even more preferably 25 μm or less.

[0086] <Other Layers> The pressure-sensitive adhesive layer-attached polarizing plate of the present invention may include other members in addition to the various members described above. For example, the pressure-sensitive adhesive layer-attached polarizing plate of the present invention may further include an adhesion layer in order to improve adhesion between members.

[0087] The adhesion layer is a layer selected from the group consisting of an adhesive layer and a pressure-sensitive adhesive layer. The adhesive layer is a layer formed using an adhesive. For example, a layer formed by curing an adhesive can be used. Examples of adhesives include curable adhesives such as active energy ray-curable adhesives and thermosetting adhesives. Examples of active energy ray-curable adhesives include electron beam-curable adhesives, ultraviolet ray-curable adhesives, and visible light-curable adhesives, with ultraviolet ray-curable adhesives being preferred. In other words, the adhesion layer is preferably a layer formed by curing an ultraviolet ray-curable adhesive. Specific examples of active energy ray-curable adhesives include (meth)acrylate adhesives. Examples of curable components in (meth)acrylate adhesives include compounds having a (meth)acryloyl group and compounds having a vinyl group.

[0088] Polyvinyl alcohol adhesives (PVA adhesives) are also preferred as adhesives. Examples of polyvinyl alcohol adhesives include adhesives made of polyvinyl alcohol or its derivatives. Examples of polyvinyl alcohol derivatives include polyvinyl formal and polyvinyl acetal. Other examples include olefins such as ethylene and propylene, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and their alkyl esters, or those modified with acrylamide.

[0089] The thickness of the adhesive layer is not particularly limited, and the lower limit of the thickness is preferably 0.1 μm or more, more preferably 0.2 μm or more, and even more preferably 0.5 μm or more. The upper limit of the thickness is preferably 5 μm or less, and more preferably 2 μm or less.

[0090] Examples of the pressure-sensitive adhesive layer include those exemplified as the pressure-sensitive adhesive layer contained in the above-mentioned polarizing plate with a pressure-sensitive adhesive layer.

[0091] In particular, the polarizer and the positive A plate are preferably laminated via an adhesive layer, more preferably via a polyvinyl alcohol adhesive, and also preferably via an adhesive layer formed by curing an ultraviolet-curable adhesive.

[0092] The pressure-sensitive adhesive layer-attached polarizing plate of the present invention may further have a cover film on the protective film to protect the protective film. The presence of the cover film can further prevent the protective film from being damaged during handling.

[0093] When the polarizing plate with a pressure-sensitive adhesive layer of the present invention is bonded to a glass substrate via a pressure-sensitive adhesive and a cross-cut test with 100 squares is performed on the bonded polarizing plate with a pressure-sensitive adhesive layer, it is preferable that the number of squares that peel off is 50 or less. In the present invention, a polymer film may be included as part of the positive C plate, but since the polymer film is laminated with good adhesion to the adjacent layer, peeling is unlikely to occur even in the cross-cut test. In other words, peeling is unlikely to occur between the polymer film and the layer adjacent to the polymer film in the cross-cut test. The cross-cut test can be performed in accordance with JIS-K5600-5-6 (1999).

[0094] <Method for manufacturing a polarizing plate with a pressure-sensitive adhesive layer> The method for manufacturing the polarizing plate with a pressure-sensitive adhesive layer of the present invention is not particularly limited, and the polarizing plate can be manufactured by a known method. For example, the polarizing plate with a pressure-sensitive adhesive layer may be manufactured by preparing various components constituting the polarizing plate with a pressure-sensitive adhesive layer, and laminating the various components via the above-mentioned adhesion layer, or by directly laminating the various components without the adhesion layer. More specifically, while transporting a polarizer, a protective film may be attached to one surface of the polarizer, and a laminate film including a positive A plate and a positive C plate may be attached to the other surface of the polarizer to manufacture a polarizing plate, and a pressure-sensitive adhesive layer may be disposed on the positive C plate side of the obtained polarizing plate.

[0095] The positive A plate is preferably formed using a composition containing a polymerizable liquid crystal compound. More specifically, the positive A plate is preferably produced by applying a composition containing a polymerizable liquid crystal compound, subjecting the formed coating to an alignment treatment to align the polymerizable liquid crystal compound in the coating, and then subjecting the coating to a curing treatment. Components contained in the composition include the above-mentioned polymerizable liquid crystal compound and a polymer having a group represented by formula (1). Other components that may be contained in the composition include, in addition to the above, a monomer, a polymerization initiator, a photoacid generator, an alignment control agent (vertical alignment agent, horizontal alignment agent), a surfactant, an adhesion improver, a plasticizer, and a solvent.

[0096] The composition can be applied to a substrate having an alignment film. The alignment film may be a photo-alignment film. The composition can be applied by curtain coating, dip coating, spin coating, print coating, spray coating, slot coating, roll coating, slide coating, blade coating, gravure coating, or wire bar coating.

[0097] The alignment treatment can be carried out by drying the coating film at room temperature or by heating the coating film. In the case of a thermotropic liquid crystal compound, the liquid crystal phase formed by the alignment treatment can generally be transitioned by a change in temperature or pressure. In the case of a lyotropic liquid crystal compound, the transition can also be achieved by adjusting the composition ratio, such as the amount of solvent. The conditions for heating the coating film are not particularly limited, but the heating temperature is preferably 50 to 250°C, more preferably 50 to 150°C, and the heating time is preferably 10 seconds to 10 minutes. After heating the coating film, the coating film may be cooled, if necessary, before the curing treatment (light irradiation treatment) described below.

[0098] The method of curing the coating film in which the polymerizable liquid crystal compound is oriented is not particularly limited, and examples thereof include light irradiation and heat treatment. Among these, from the viewpoint of manufacturability, light irradiation is preferred, and ultraviolet irradiation is more preferred. The irradiation conditions for the light irradiation are not particularly limited, but are preferably 50 to 1000 mJ / cm. ２ The atmosphere during the light irradiation treatment is not particularly limited, but a nitrogen atmosphere is preferred.

[0099] As a method for producing a positive C plate, a method using a composition containing a polymerizable liquid crystal compound can be used, similar to the method for producing the positive A plate described above. The composition may contain a polymerizable liquid crystal compound, a crosslinkable polymer, and a photoisomerizable compound. When the composition contains a photoisomerizable compound, the photoisomerizable compound may have a polymerizable group. In addition, when the positive C plate includes a vertically aligned liquid crystal layer and a polymer film, the above composition may be applied to the polymer film to form the vertically aligned liquid crystal layer.

[0100] In the present invention, a composition for forming a positive A plate may be applied to a positive C plate to form a positive A plate laminated directly on the positive C plate. In the above-described procedure, a photoisomerizable compound is disposed on the surface of the positive C plate on which the positive A plate is to be formed, and the photoisomerizable compound is irradiated with light to impart the function of a photo-alignment film. For example, when the positive C plate includes a vertically aligned liquid crystal layer and a polymer film and a composition is applied to the vertically aligned liquid crystal layer to form a positive A plate, the photoisomerizable compound is disposed on the surface of the vertically aligned liquid crystal layer opposite the polymer film side, and light irradiation is performed to align the photoisomerizable group contained in the photoisomerizable compound, thereby imparting alignment ability to the surface of the vertically aligned liquid crystal layer.

[0101] <Applications> The polarizing plate with a pressure-sensitive adhesive layer of the present invention can be suitably applied to display devices. More specifically, the polarizing plate with a pressure-sensitive adhesive layer of the present invention having the above-mentioned configuration is suitably used for anti-reflection applications in display devices such as liquid crystal displays (LCDs), plasma display panels (PDPs), electroluminescent displays (ELDs), and cathode ray tube displays (CRTs). The display device of the present invention has a display element and the above-mentioned polarizing plate with a pressure-sensitive adhesive layer. When using the polarizing plate with a pressure-sensitive adhesive layer of the present invention in a display device, a method can be used in which the display element and the polarizing plate with a pressure-sensitive adhesive layer are bonded together, with the pressure-sensitive adhesive layer in the polarizing plate with a pressure-sensitive adhesive layer facing the display element. The display element is not particularly limited, and examples include organic electroluminescent display elements and liquid crystal display elements.

[0102] The features of the present invention will be explained in more detail below with reference to examples and comparative examples. The materials, amounts used, ratios, treatment details, and treatment procedures shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[0103] Example 1 (Preparation of Cellulose Acylate Film (1)) The following composition was charged into a mixing tank, stirred, and heated at 90°C for 10 minutes. The resulting composition was then filtered through a filter paper having an average pore size of 34 μm and a sintered metal filter having an average pore size of 10 μm to prepare a dope. The solid content of the dope was 23.5% by mass, and the solvent for the dope was methylene chloride / methanol / butanol = 81 / 18 / 1 (mass ratio).

[0104] ------------------------------------------------ Cellulose acylate dope ------------------------------------------------ Cellulose acylate (acetyl substitution degree 2.86, viscosity average degree of polymerization 310) 100 parts by mass Sugar ester compound 1 (shown in the following formula (S4)) 6.0 parts by mass Sugar ester compound 2 (shown in the following formula (S5)) 2.0 parts by mass Silica particle dispersion (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) 0.1 part by mass Solvent (methylene chloride / methanol / butanol) ------------------------------------------------

[0105]

[0106]

[0107] The dope prepared above was cast using a drum film-forming machine. The dope was cast from a die onto a metal support cooled to 0°C, and then the resulting web (film) was peeled off. The drum was made of SUS.

[0108] The web (film) obtained by casting was peeled from the drum and then dried for 20 minutes in a tenter apparatus, which clipped both ends of the web with clips while transporting the film at 30 to 40°C. Subsequently, the web was post-dried by zone heating while being transported with a roll. The obtained web was knurled and then wound up to prepare a cellulose acylate film (1) with a thickness of 40 μm. The in-plane retardation of the cellulose acylate film (1) at a wavelength of 550 nm was 0 nm, and the retardation in the thickness direction at a wavelength of 550 nm was 23 nm.

[0109] (Formation of Positive C Plate (1A)) A composition for forming a vertically aligned liquid crystal layer (1A) containing a rod-shaped liquid crystal compound having the following composition was applied onto the above cellulose acylate film using a Giesser coater to form a composition layer. The film on which the composition layer was formed was heated with warm air at 60°C for 1 minute, and then irradiated with a 365 nm UV-LED at an irradiation dose of 100 mJ / cm while purging with nitrogen so that the atmosphere had an oxygen concentration of 100 ppm by volume or less. ２ The coating film was then irradiated with ultraviolet light of 1000 kJ / cm. Thereafter, the resulting coating film was annealed with hot air at 130°C for 1 minute to form a 40.7 µm thick positive C plate (1A) in which a 0.7 µm thick vertically aligned liquid crystal layer (1A) was formed on the cellulose acylate film. The in-plane retardation Re of the positive C plate (1A) at a wavelength of 550 nm was 0 nm, and the retardation Rth in the thickness direction at a wavelength of 550 nm was -85 nm. The average tilt angle of the long axis direction of the rod-like liquid crystal compounds with respect to the film plane was 90°, confirming that they were aligned perpendicular to the film plane.

[0110] ------------------------------------------------ Composition for forming a vertically aligned liquid crystal layer (1A) -------------------------------------------------- Rod-shaped liquid crystal compound (A) below: 100 parts by mass Polymerizable monomer (A-400, manufactured by Shin-Nakamura Chemical Co., Ltd.) 4.2 parts by mass Polymerization initiator S-1 (oxime type) below: 5.1 parts by mass Photoacid generator D-1 below: 3.0 parts by mass Polymer M-1 below: 4.0 parts by mass Alignment control agent A-1 below: 1.9 parts by mass Photoalignment polymer PA-1 below: 0.8 parts by mass Diisopropylethylamine 0.2 parts by mass Methyl ethyl ketone 93.8 parts by mass Methyl isobutyl ketone 372.0 parts by mass --------------------------------------------------

[0111] Rod-like liquid crystal compound (A) (hereinafter referred to as a mixture of compounds. Numerical values ​​indicate mass ratios.)

[0112]

[0113] Polymerization initiator S-1

[0114]

[0115] Photoacid generator D-1

[0116]

[0117] Polymer M-1 (weight average molecular weight was 52,000. The numerical values ​​shown in the repeating units indicate the content (% by mass) of each repeating unit relative to all repeating units.)

[0118]

[0119] Alignment control agent A-1

[0120]

[0121] Photoalignment polymer PA-1 (The numerical values ​​shown in the repeating units represent the content (mass%) of each repeating unit relative to all repeating units. Weight average molecular weight: 90,000. Me represents a methyl group.)

[0122]

[0123] (Preparation of Positive A Plate (1B)) UV light (ultra-high pressure mercury lamp; UL750; manufactured by HOYA) was irradiated at 7.9 mJ / cm 2 through a wire grid polarizer onto the vertically aligned liquid crystal layer (1A) side of the long positive C plate (1A). ２ The film was then irradiated with ultraviolet light (wavelength: 313 nm) to form a composition layer having alignment controllability on the surface. Subsequently, a composition for forming a horizontally aligned liquid crystal layer (1B) containing a rod-shaped liquid crystal compound having the following composition was applied onto the vertically aligned liquid crystal layer (1A) using a Giesser coater, and the film was heated to 120°C with hot air and then cooled to 60°C to stabilize the alignment. Thereafter, the film was irradiated with ultraviolet light (80 mJ / cm) for the first time in a nitrogen atmosphere (oxygen concentration less than 100 ppm) using an ultra-high pressure mercury lamp, with the film temperature kept at 60°C. ２), the film temperature was kept at 100°C and the second ultraviolet irradiation (300 mJ / cm ２ The alignment was fixed by ) to form a positive A plate (1B). The thickness of the positive A plate (1B) was 2.8 μm, and the Re(550) at a wavelength of 550 nm was 141 nm. When the width direction of the film was set to 0° (the longitudinal direction was 90°), the in-plane slow axis direction (the alignment axis angle of the liquid crystal compound) was 45°.

[0124] ------------------------------------------------ Composition for forming horizontally aligned liquid crystal layer (1B)------------------------------------------------ 21.2 parts by mass of the following rod-shaped liquid crystal compound (B) 26.1 parts by mass of the following rod-shaped liquid crystal compound (C) 29.0 parts by mass of the following rod-shaped liquid crystal compound (D) 8.5 parts by mass of the following rod-shaped liquid crystal compound (E) 15.3 parts by mass of the following rod-shaped liquid crystal compound (F) 0.5 part by mass of the above polymerization initiator S-1 (oxime type) 0.1 part by mass of the following leveling agent L-1 Cyclopentanone 175.0 parts by mass Methyl ethyl ketone 50.0 parts by mass Ethyl laurate 10.0 parts by mass

[0125] Rod-shaped liquid crystal compound (B)

[0126]

[0127] Rod-shaped liquid crystal compound (C)

[0128]

[0129] Rod-shaped liquid crystal compound (D)

[0130]

[0131] Rod-shaped liquid crystal compound (E)

[0132]

[0133] Rod-shaped liquid crystal compound (F)

[0134]

[0135] Leveling agent L-1 (weight average molecular weight was 28,500. The numerical values ​​shown in the repeating units represent the content (mass%) of each repeating unit relative to all repeating units.)

[0136]

[0137] By the above procedure, a long laminated film (1) having a thickness of 43.5 μm was prepared in which the positive C plate (1A) and the positive A plate (1B) were directly laminated together.

[0138] (Preparation of PVA adhesive) 100 parts by mass of a polyvinyl alcohol resin having acetoacetyl groups (average degree of polymerization: 1200, degree of saponification: 98.5 mol%, degree of acetoacetylation: 5 mol%) and 20 parts by mass of methylol melamine were dissolved in pure water at a temperature of 30°C, and the resulting aqueous solution was adjusted to a solids concentration of 3.7% by mass, thereby preparing a PVA adhesive.

[0139] (Preparation of Pressure-Sensitive Adhesive Layer) A pressure-sensitive adhesive layer (acrylic pressure-sensitive adhesive) having a thickness of 20 μm was formed on a separator film in the same manner as described in Example 1 of JP-A No. 2023-126297.

[0140] (Preparation of Polarizing Plate (P1)) The support surface of a cellulose triacetate film TJ25 (manufactured by Fujifilm Corporation; thickness: 25 μm) was subjected to alkaline saponification treatment. Specifically, the support was immersed in a 1.5 N sodium hydroxide aqueous solution at 55°C for 2 minutes, then washed in a water wash bath at room temperature, and further neutralized with 0.1 N sulfuric acid at 30°C. After neutralization, the support was washed in a water wash bath at room temperature and further dried with hot air at 100°C to obtain a polarizer protective film (1). A rolled polyvinyl alcohol (PVA) film having a thickness of 60 μm was continuously stretched in the longitudinal direction in an iodine aqueous solution and dried to obtain a polarizer (1) having a thickness of 13 μm. The luminous efficiency-corrected single transmittance of the polarizer (1) was 43%. At this time, the absorption axis direction and the longitudinal direction of the polarizer (1) were aligned. The surface of the positive A plate (1B) of the long laminate film (1) prepared above was bonded to one side of the polarizer (1), and the polarizer protective film (1) was bonded to the other side of the polarizer (1) using the PVA adhesive. Then, a 50 μm thick laminate film made of a PET (polyethylene terephthalate) film with a weak adhesive was bonded to the polarizer protective film (1) side. Then, the adhesive layer formed on the separator film was bonded to the laminate film (1) side. A polarizing plate (P1) with an adhesive layer was prepared using the above procedure. At this time, the laminate film, polarizer protective film (1), PVA adhesive layer (thickness 0.2 μm), polarizer (1), PVA adhesive layer (thickness 0.2 μm), positive A plate (1B), positive C plate (1A) (vertical alignment liquid crystal layer (1A), cellulose acylate film (1)), pressure-sensitive adhesive layer, and separator film were laminated in this order, and the angle formed by the absorption axis of the polarizer (1) and the in-plane slow axis of the positive A plate (1B) was 45°.

[0141] A cellulose acylate film (2) having a thickness of 20 μm was produced in the same manner as in the production of the cellulose acylate film (1). A laminate film (2) having a thickness of 23.5 μm and having a positive C plate (2A) and a positive A plate (2B) laminated thereon, and a polarizing plate (P2) with a pressure-sensitive adhesive layer were produced in the same manner as in Example 1, except that the cellulose acylate film (1) was replaced with the cellulose acylate film (2).

[0142] Comparative Example 1 A cellulose acylate film (3) having a thickness of 15 μm was produced in the same manner as in the cellulose acylate film (1). A laminate film (3) having a thickness of 18.5 μm and having a positive C plate (3A) and a positive A plate (3B) laminated thereon, and a polarizing plate (P3) with a pressure-sensitive adhesive layer were produced in the same manner as in Example 1, except that the cellulose acylate film (1) was replaced with the cellulose acylate film (3).

[0143] Example 3 The polarizer protective film (1) was bonded to one surface of the polarizer (1) produced by the method of Example 1 using the PVA adhesive, to produce a single-sided polarizing plate (1). Furthermore, a 50 μm-thick laminate film made of a PET film with a weak adhesive was bonded to the polarizer protective film (1) side. The surface of the positive A plate (1B) side of the laminated film (1) produced in Example 1 and the surface of the polarizer side of the single-sided polarizing plate (1) produced above were each subjected to a corona treatment, and then the films were bonded together using an ultraviolet-curable adhesive composition (1) having the following composition so that the longitudinal directions of the films were parallel, and then the laminated film (1) was irradiated with ultraviolet light (600 mJ / cm) from the laminated film (1) side. ２) and cured, and then the pressure-sensitive adhesive layer formed on the separator film was attached to produce a polarizing plate (P4) with a pressure-sensitive adhesive layer. -------------------------------------------------------------------------------- UV-curable adhesive composition (1) -------------------------------------------------------------------------------- CEL2021P (manufactured by Daicel) 70.0 parts by mass 2-ethylhexyl glycidyl ether 10.0 parts by mass Rikaresin DME-100 (manufactured by New Japan Chemical Co., Ltd.) 20.0 parts by mass CPI-100P (manufactured by San-Apro) 4.5 parts by mass At this time, the laminate film, polarizer protective film (1), PVA adhesive layer (thickness: 0.2 μm), polarizer (1), adhesive layer (adhesive layer obtained by curing an ultraviolet-curable adhesive composition, thickness: 1 μm), positive A plate (1B), positive C plate (1A), pressure-sensitive adhesive layer, and separator film were laminated in this order, and the angle formed by the absorption axis of the polarizer (1) and the in-plane slow axis of the positive A plate (1B) was 45°.

[0144] Example 4 Polymer M-1 used in composition (1A) for forming a vertically aligned liquid crystal layer was changed to polymer M-2 below, to prepare composition (5A) for forming a vertically aligned liquid crystal layer.

[0145] Polymer M-2 (weight average molecular weight was 60,000. The numerical values ​​shown in the repeating units represent the content (% by mass) of each repeating unit relative to all repeating units.)

[0146]

[0147] The vertically aligned liquid crystal layer-forming composition (1A) was changed to the vertically aligned liquid crystal layer-forming composition (5A), and a positive C plate (5B) consisting of the vertically aligned liquid crystal layer (5A) and the cellulose acylate film (1) was produced by the method described in Example 1. Subsequently, a positive A plate (5B) was formed on the surface of the vertically aligned liquid crystal layer (5A) in the same manner as the positive A plate (1B), and a long laminate film (5) having a thickness of 40.7 μm was produced in which the positive C plate (5A) and the positive A plate (5B) were directly laminated. The positive A plate (5B) side of the laminate film (5) was attached to the polarizer (1) side of the single-sided polarizing plate (1) using the ultraviolet-curable adhesive composition (1), and ultraviolet light (600 mJ / cm) was irradiated from the laminate film (5) side. ２ ), and cured, and then a pressure-sensitive adhesive layer formed on the separator film was attached thereto to prepare a polarizing plate (P5) with a pressure-sensitive adhesive layer. At this time, the polarizer protective film (1), the PVA adhesive layer (thickness: 0.2 μm), the polarizer (1), the adhesive layer (adhesive layer obtained by curing an ultraviolet-curable adhesive composition, thickness: 1 μm), the positive A plate (5B), the vertically aligned liquid crystal layer (5A), the cellulose acylate film (1), the pressure-sensitive adhesive layer, and the separator film were laminated in this order, and the angle formed by the absorption axis of the polarizer (1) and the in-plane slow axis of the positive A plate (5B) was 45°.

[0148] Comparative Example 2 In the method described in Example 4, the laminate film (5) was attached to the polarizer (1), and then the cellulose acylate film (1) was peeled off. Subsequently, the pressure-sensitive adhesive layer formed on the separator film was attached to the laminate film (5). This produced a polarizing plate (P6) with a pressure-sensitive adhesive layer, in which the laminate film, the polarizer protective film (1), the PVA adhesive layer (thickness: 0.2 μm), the polarizer (1), the adhesive layer (adhesive layer obtained by curing an ultraviolet-curable adhesive composition, thickness: 1 μm), the positive A plate (5B), the positive C plate (6A) composed of the vertically aligned liquid crystal layer (5A), the pressure-sensitive adhesive layer, and the separator film were laminated in this order.

[0149] Example 5 (Preparation of Positive C Plate (7A)) A composition for forming a vertically aligned liquid crystal layer (7A) containing a rod-shaped liquid crystal compound having the following composition was applied onto the cellulose acylate film (1) using a Giesser coater to form a composition layer. The film on which the composition layer was formed was heated with warm air at 60°C for 1 minute, and then irradiated with a 365 nm UV-LED at an irradiation dose of 100 mJ / cm while purging with nitrogen so that the atmosphere had an oxygen concentration of 100 ppm by volume or less. ２ The coating film was then irradiated with ultraviolet light of 1000 kJ / cm. Thereafter, the resulting coating film was annealed with hot air at 130°C for 1 minute to form a 40.7 μm thick positive C plate (7A) consisting of a 0.7 μm thick vertically aligned liquid crystal layer (7A) and a cellulose acylate film (1). The in-plane retardation Re of the positive C plate (7A) at a wavelength of 550 nm was 0 nm, and the thickness direction retardation Rth at a wavelength of 550 nm was -85 nm. The average tilt angle of the long axis direction of the rod-like liquid crystal compounds with respect to the film plane was 90°, confirming that they were aligned perpendicular to the film plane. ------------------------------------------------ Composition for forming a vertically aligned liquid crystal layer (7A)------------------------------------------------ Rod-shaped liquid crystal compound (A) 100 parts by mass Polymerizable monomer (A-400, manufactured by Shin-Nakamura Chemical Co., Ltd.) 4.2 parts by mass Polymerization initiator S-1 (oxime type) 5.1 parts by mass Photoacid generator D-1 3.0 parts by mass Polymer M-1 4.0 parts by mass Alignment control agent A-1 1.9 parts by mass Leveling agent L-1 0.8 parts by mass Diisopropylethylamine 0.2 parts by mass Methyl ethyl ketone 93.8 parts by mass Methyl isobutyl ketone 372.0 parts by mass

[0150] (Preparation of Positive A Plate (7B)) A positive A plate (7B) formed on a TAC film A-1 was prepared in the same manner as the positive A plate A-1 described in Example 1 of International Publication No. 2020-050305. The thickness of the positive A plate (7B) was 2.5 μm, and the in-plane retardation at a wavelength of 550 nm was 144 nm.

[0151] (Preparation of Polarizing Plate (P7)) The surfaces of the prepared positive C plate (7A) and positive A plate (7B) were subjected to a corona treatment, and then they were laminated using the above-mentioned ultraviolet-curable adhesive composition (1). After peeling off the support on the positive A plate (7B) side, the peeled surface was subjected to a corona treatment, and they were laminated with a single-sided polarizing plate in the same manner as in Example 3. The adhesive layer formed on the separator film was laminated to the surface of the cellulose acylate film (1), thereby preparing a polarizing plate (P7) with an adhesive layer. At this time, the laminate film, the polarizer protective film (1), the PVA adhesive layer (thickness 0.2 μm), the polarizer (1), the adhesive layer (adhesive layer obtained by curing an ultraviolet-curable adhesive composition, thickness 1 μm), the positive A plate (7B), the adhesive layer (adhesive layer obtained by curing an ultraviolet-curable adhesive composition, thickness 1 μm), the positive C plate (7A) (vertically aligned liquid crystal layer (7A), cellulose acylate film (1)), the pressure-sensitive adhesive layer, and the separator film were laminated in this order, and the angle formed by the absorption axis of the polarizer (1) and the in-plane slow axis of the positive A plate (7B) was 45°.

[0152] Comparative Example 3 (Preparation of Positive C Plate (8A)) The polymer M-1 in the vertically aligned liquid crystal layer-forming composition (7A) was replaced with the polymer M-2, and a vertically aligned liquid crystal layer-forming composition (8A) was prepared. A vertically aligned liquid crystal layer (8A) prepared in the same manner as in Example 5, except that the vertically aligned liquid crystal layer-forming composition (7A) was replaced with the vertically aligned liquid crystal layer-forming composition (8A), was bonded to a positive A plate (7B), and the support of the positive A plate (7B) was peeled off, followed by bonding to a single-sided polarizing plate using a UV-curable adhesive. Subsequently, the support (cellulose acylate film (1)) on the vertically aligned liquid crystal layer (8A) side was peeled off, and the pressure-sensitive adhesive layer formed on the separator film was attached to prepare a polarizing plate (P8) with a pressure-sensitive adhesive layer. At this time, the laminate film, the polarizer protective film (1), the PVA adhesive layer (thickness: 0.2 μm), the polarizer (1), the adhesive layer (adhesive layer obtained by curing an ultraviolet-curable adhesive composition, thickness: 1 μm), the positive A plate (7B), the adhesive layer (adhesive layer obtained by curing an ultraviolet-curable adhesive composition, thickness: 1 μm), the vertically aligned liquid crystal layer (8A), the pressure-sensitive adhesive layer, and the separator film were laminated in this order, and the angle formed by the absorption axis of the polarizer (1) and the in-plane slow axis of the positive A plate (7B) was 45°.

[0153] Example 6 A polarizing plate (P9) with an adhesive layer was prepared in the same manner as the polarizing plate (P1) of Example 1, except that the leveling agent L-1 in the composition (1B) for forming a horizontally aligned liquid crystal layer was changed to the leveling agent L-2 described below.

[0154] Leveling agent L-2 (The numerical values ​​shown in the repeating units indicate the content (mass%) of each repeating unit relative to all repeating units. The weight-average molecular weight was 28,500.)

[0155]

[0156] Example 7 (Preparation of Polarizing Plate (P10)) The polarizer protective film (1) was attached to both sides of the polarizer (1) using a PVA adhesive to prepare a double-sided protected polarizing plate (2). Furthermore, a 50 μm-thick laminate film made of a PET film with a weak adhesive was attached to the polarizer protective film (1). Subsequently, the coated surface of the laminate film (1) and one side of the prepared double-sided protected polarizing plate (2) were each subjected to a corona treatment, and then the laminate was attached to the film using an ultraviolet-curable adhesive composition (1) having the above composition so that the longitudinal directions of the films were parallel to each other, and then the laminate was subjected to ultraviolet irradiation (600 mJ / cm ２ ), and cured, a polarizing plate (P10) with a pressure-sensitive adhesive layer was produced. At this time, the laminate film, the polarizer protective film (1), the PVA adhesive layer (thickness 0.2 μm), the polarizer (1), the PVA adhesive layer (thickness 0.2 μm), the polarizer protective film (1), the adhesive layer (adhesive layer obtained by curing an ultraviolet-curable adhesive composition, thickness 1 μm), the positive A plate (1B), the positive C plate (1A) (vertically aligned liquid crystal layer (1A), cellulose acylate film (1)), the pressure-sensitive adhesive layer, and the separator film were laminated in this order, and the angle formed by the absorption axis of the polarizer (1) and the in-plane slow axis of the positive A plate (1B) was 45°.

[0157] Comparative Example 4 A photo-alignment film and a liquid crystal layer were formed on a cellulose acylate film by the method described in Example 1 of International Publication No. 2019-111880, to prepare a positive A plate (11B). After corona treatment was performed on the coated surface of the positive A plate (11B), the composition for forming a cured resin layer described in paragraph

[0211] of JP-A No. 2019-139219 was applied, dried at 50°C for 1 minute, and then irradiated with ultraviolet light using a high-pressure mercury lamp (under a nitrogen atmosphere, cumulative light intensity at a wavelength of 365 nm: 400 mJ / cm). ２) to form a cured resin layer having a thickness of 2.0 μm. The obtained cured resin layer was used as an alignment film, and the following composition for forming a vertically aligned liquid crystal layer (11A) was applied to form a composition layer. The film on which the composition layer was formed was heated with hot air at 60°C for 1 minute, and then irradiated with a 365 nm UV-LED at an irradiation dose of 100 mJ / cm while purging with nitrogen so that the atmosphere had an oxygen concentration of 100 ppm by volume or less. ２ The coating film was then annealed with warm air at 130°C for 1 minute to form a 0.7µm thick positive C plate (11A) comprising a 0.7µm thick vertically aligned liquid crystal layer (11A), thereby producing a laminated film (11). -------------------------------------------------------------------------------- Composition for forming a vertically aligned liquid crystal layer (11A) ---------------------------------------------------------------- Rod-like liquid crystal compound (A) 100 parts by mass Polymerizable monomer (A-400, manufactured by Shin-Nakamura Chemical Co., Ltd.) 4.2 parts by mass Polymerization initiator S-1 (oxime type) 5.1 parts by mass Alignment control agent A-1 1.9 parts by mass Leveling agent L-1 0.5 parts by mass Diisopropylethylamine 0.2 parts by mass Methyl ethyl ketone 466 parts by mass

[0158] A laminate film consisting of a 50 μm thick PET film with a weak adhesive was attached to the polarizer protective film (1) side of the single-sided polarizing plate (1), and then the polarizer side surface and the cellulose acylate film surface of the laminated film (11) were each corona treated and then attached using the above-mentioned ultraviolet-curable adhesive.An adhesive layer formed on a separator film was then attached to the surface of the vertically aligned liquid crystal layer (11A) to produce a polarizing plate (P11) with an adhesive layer. At this time, the laminate film, the polarizer protective film (1), the PVA adhesive layer (thickness: 0.2 μm), the polarizer (1), the adhesive layer (adhesive layer obtained by curing an ultraviolet-curable adhesive composition, thickness: 1 μm), the cellulose acylate film, the positive A plate (11B), the cured resin layer, the vertically aligned liquid crystal layer (11A), the pressure-sensitive adhesive layer, and the separator film were laminated in this order, and the angle formed by the absorption axis of the polarizer (1) and the in-plane slow axis of the positive A plate (11B) was 45°.

[0159] Example 8 A positive C plate (7A) was prepared by the method described in Example 5, and then the surface of the vertically aligned liquid crystal layer (7A) was subjected to corona treatment. A horizontally aligned film and a horizontally aligned liquid crystal cured film were prepared by the method described in paragraph 0214 of JP-A-2019-139219. The horizontally aligned liquid crystal cured film was used as a positive A plate (12B), and a laminate film (12) was obtained. The in-plane retardation of the positive A plate (12B) at a wavelength of 550 nm was 142 nm. A polarizing plate (P12) with an adhesive layer was prepared in the same manner as in Example 5, except that the laminate film (12) was used instead of the laminate film (3). At this time, the laminate film, the polarizer protective film (1), the PVA adhesive layer (thickness: 0.2 μm), the polarizer (1), the adhesive layer (adhesive layer obtained by curing an ultraviolet-curable adhesive composition, thickness: 1 μm), the positive A plate (12B), the horizontal alignment film, the vertically aligned liquid crystal layer (7A), the cellulose acylate film (1), the pressure-sensitive adhesive layer, and the separator film were laminated in this order, and the angle formed by the absorption axis of the polarizer (1) and the in-plane slow axis of the positive A plate (12B) was 45°.

[0160] Example 9 A laminate consisting of a substrate, a cured resin layer, a vertically aligned liquid crystal layer (corresponding to the vertically aligned liquid crystal cured film of JP 2019-139219 A), a horizontally aligned film, and a horizontally aligned liquid crystal layer was produced by the method described in paragraphs 0202 to 0215 of JP 2019-139219 A, and named laminate film (13). A polarizing plate (P13) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 5, except that laminate film (13) was used instead of laminate film (3). At this time, the laminate film, polarizer protective film (1), PVA adhesive layer (thickness 0.2 μm), polarizer (1), adhesive layer (adhesive layer obtained by curing an ultraviolet-curable adhesive composition, thickness 1 μm), horizontally aligned liquid crystal layer (corresponding to a positive A plate), horizontal alignment film, positive C plate (vertically aligned liquid crystal layer, cured resin layer, substrate (TAC film)), pressure-sensitive adhesive layer, and separator film were laminated in this order, and the angle formed by the absorption axis of the polarizer (1) and the in-plane slow axis of the horizontally aligned liquid crystal layer was 45°. A positive C plate was constructed including the vertically aligned liquid crystal layer, cured resin layer, and substrate, and the in-plane retardation of this positive C plate at a wavelength of 550 nm was 0 nm and the retardation in the thickness direction at a wavelength of 550 nm was −70 nm. The thickness of the vertically aligned liquid crystal layer was 0.7 μm, and the thickness of the substrate (TAC film) was 40.0 μm. The in-plane retardation of the horizontally aligned liquid crystal layer (corresponding to a positive A plate) at a wavelength of 550 nm was 141 nm.

[0161] Example 10 A polarizing plate (P14) with a pressure-sensitive adhesive was produced in the same manner as in Example 1, except that the thickness of the pressure-sensitive adhesive layer (pressure-sensitive adhesive layer formed on the separator film) described in Example 1 was changed from 20 μm to 40 μm.

[0162] Example 11 A polarizing plate (P15) with a pressure-sensitive adhesive was produced in the same manner as in Example 1, except that the thickness of the pressure-sensitive adhesive layer (pressure-sensitive adhesive layer formed on the separator film) described in Example 1 was changed from 20 μm to 10 μm.

[0163] <Measurement of Optical Properties> Using an AxoScan OPMF-1 (manufactured by OptoScience Corporation), the dependence of Re on the light incident angle and the tilt angle of the optical axis (i.e., the tilt of the direction in which the refractive index of the optically anisotropic layer is maximized relative to the surface of the optically anisotropic layer) were measured at a wavelength of 550 nm, and the in-plane retardation Re at a wavelength of 550 nm and the retardation Rth in the thickness direction at a wavelength of 550 nm of the optically anisotropic layer were determined.

[0164] <Measurement of Film Thickness of Laminated Film> The thickness of the laminated film was measured using a contact type film thickness meter.

[0165] <Measurement of Liquid Crystal Layer Thickness> The thickness of the liquid crystal layer was measured using a reflection spectroscopic film thickness meter FE3000 (manufactured by Otsuka Electronics Co., Ltd.).

[0166] <Measurement of Film Thickness of Laminated Film and Polymer Film> The thickness of the laminated film and polymer film was measured using a contact film thickness meter.

[0167] <Adhesion Evaluation> The prepared polarizing plate with the pressure-sensitive adhesive layer was cut into strips measuring 30 mm x 120 mm, and the separator film on the pressure-sensitive adhesive layer side was peeled off. The exposed pressure-sensitive adhesive layer was attached to glass, and the laminate film on the opposite side was peeled off. Eleven cuts were made at 1 mm intervals from the surface of the polarizing plate to a depth that reached the pressure-sensitive adhesive attached to the glass, and eleven more cuts were made in the same direction perpendicular to the cuts to form 100 grids. Adhesive tape (polyester adhesive tape No. 31B, manufactured by Nitto Denko) was attached to the grids, and the tape was peeled off at an angle of approximately 60°. The number of peeled grids was counted, and the results were evaluated according to the following criteria: A: 50 or fewer peeled grids; B: 51 or more peeled grids.

[0168] <Evaluation of Processing Suitability (Curl)> The polarizing plates with pressure-sensitive adhesive layers obtained in each Example and Comparative Example were cut into a size of 200 mm x 200 mm so that the MD direction was the diagonal, and the separator film was peeled off to prepare samples. Next, the obtained samples were left in an environment of 25°C and 60% humidity for 3 hours or more, and then placed on a glass substrate with the peeled surface facing up, and evaluated as follows. The higher the rating, the more suppressed the curl of the polarizing plate with pressure-sensitive adhesive layer. A: The polarizing plate floated 10 mm or less from the substrate, allowing for easy lamination. B: The polarizing plate floated more than 10 mm but not more than 20 mm from the substrate, allowing for lamination. C: The polarizing plate floated more than 20 mm but not more than 30 mm from the substrate, allowing for lamination. D: The polarizing plate floated more than 30 mm from the substrate, making lamination difficult.

[0169] <Reworkability Evaluation> The cover glass and polarizing plate were peeled off from a commercially available smartphone, Galaxy A1 (manufactured by SAMUSUNG), to expose the glass on the surface of the OLED substrate. The polarizing plate with the adhesive layer prepared above was cut to the same size as the smartphone, the separator film was peeled off, and the plate was attached to the glass on the surface of the OLED substrate using a roller. The obtained sample was placed in an environment of 25°C and 60% humidity for 24 hours, after which the polarizing plate with the adhesive layer was carefully peeled off, and the reworkability was evaluated according to the following criteria: A: Nothing remained on the glass, and it was possible to peel it off cleanly. B: The adhesive and part of the cured liquid crystal film remained on the glass, and attempts to remove it broke the glass, making it impossible to remove.

[0170] In Table 1, the "Positive C Film Thickness (μm)" column indicates the film thickness (μm) of the positive C plate. In Table 1, the "Adhesive" column indicates the type of adhesive layer disposed between the polarizer and the positive A plate, with "PVA Adhesive" indicating a polyvinyl alcohol-based adhesive and "UV Adhesive" indicating an adhesive layer formed by curing a UV-curable adhesive. In Table 1, the "Crosslinkable Polymer" column indicates whether or not a cured crosslinkable polymer is contained in the vertically aligned liquid crystal layer, with "A" indicating that it is contained and "B" indicating that it is not contained. In the case of an evaluation of "A," the cured crosslinkable polymer in the vertically aligned liquid crystal layer was unevenly distributed on the cellulose acylate film (polymer film) side of the positive C plate. In Table 1, the "Photoisomerizable Compound" column indicates whether or not a photoisomerizable compound is contained in the vertically aligned liquid crystal layer, with "A" indicating that it is contained and "B" indicating that it is not contained. In the case of an evaluation of "A," the photoisomerizable compound was present in the vertically aligned liquid crystal layer on the surface opposite to the cellulose acylate film (polymer film) side of the positive C plate. In Table 1, the column "Formula (1)" indicates whether the positive A plate contains a polymer having a group represented by the above formula (1), with "A" indicating that it is contained and "B" indicating that it is not contained.

[0171]

[0172] As shown in the table above, the polarizing plate with a pressure-sensitive adhesive layer of the present invention exhibited the desired effects. Furthermore, a comparison between Examples 3 and 4 confirmed that the effect was even better when the vertically aligned liquid crystal layer contained a cured product of a crosslinkable polymer. Furthermore, a comparison between Examples 1 and 6 confirmed that the effect was even better when the positive A plate contained a polymer having a group represented by the above formula (1). Furthermore, a comparison between Examples 5, 8, and 9 and other Examples confirmed that the effect was even better when the vertically aligned liquid crystal layer contained a photoisomerizable compound (when the positive A plate and the positive C plate were in direct contact). Furthermore, a comparison between Example 9 and other Examples confirmed that the effect was even better when the vertically aligned liquid crystal layer and the polymer film were in direct contact.

[0173] <Confirmation of Region A and Region B> In Examples 1 to 11, the presence of a region in the polymer film containing a component derived from the liquid crystal compound contained in the vertically aligned liquid crystal layer (referred to as Region A) and a component derived from the liquid crystal compound contained in the positive A plate in the vertically aligned liquid crystal layer was confirmed, and if their presence was confirmed, the thickness of the region containing the component derived from the liquid crystal compound was measured. In all cases, it was confirmed that the thickness of Region A was within the range of 20 to 200 nm, and the thickness of Region B was within the range of 5 to 100 nm.

[0174] REFERENCE SIGNS LIST 10 Polarizing plate with adhesive layer 12 Polarizing plate 14 Protective film 16 Polarizer 18 Positive A plate 20 Positive C plate 22 Adhesive layer 24 Vertically aligned liquid crystal layer 26 Polymer film

Claims

1. A polarizing plate with an adhesive layer, comprising a polarizing plate having a protective film, a polarizer, a positive A plate, and a positive C plate in this order, and an adhesive layer arranged on the positive C plate side of the polarizing plate, wherein the positive A plate is a layer obtained by curing a polymerizable liquid crystal compound, and the thickness of the positive C plate is 20.0 to 70.0 μm.

2. The polarizing plate with an adhesive layer according to claim 1, wherein when the polarizing plate with an adhesive layer is bonded to a glass substrate via the adhesive and a cross-cut test of 100 squares is performed on the bonded polarizing plate with an adhesive layer, the number of squares that peels off is 50 or less.

3. The polarizing plate with a pressure-sensitive adhesive layer according to claim 1, wherein the positive C plate has a retardation in the thickness direction at a wavelength of 550 nm of −100 to −30 nm.

4. The polarizing plate with an adhesive layer according to claim 1, wherein the positive C plate comprises a polymer film.

5. The polarizing plate with an adhesive layer according to claim 4, wherein the polymer film is a cellulose acylate film.

6. The polarizing plate with a pressure-sensitive adhesive layer according to claim 4, wherein the in-plane retardation of the polymer film at a wavelength of 550 nm is 10 nm or less.

7. The polarizing plate with a pressure-sensitive adhesive layer according to claim 4, wherein the polymer film has a retardation in the thickness direction at a wavelength of 550 nm of −100 to 30 nm.

8. The polarizing plate with a pressure-sensitive adhesive layer according to claim 4, wherein the positive C plate comprises a vertically aligned liquid crystal layer and the polymer film.

9. The polarizing plate with a pressure-sensitive adhesive layer according to claim 8, wherein the vertically aligned liquid crystal layer contains a crosslinked material that is unevenly distributed on the polymer film side.

10. The polarizing plate with a pressure-sensitive adhesive layer according to claim 8, wherein the vertically aligned liquid crystal layer is a layer formed using a composition containing a liquid crystal compound and a crosslinkable polymer, and the crosslinkable polymer has a hydroxyl group.

11. The polarizing plate with a pressure-sensitive adhesive layer according to claim 8, wherein the vertically aligned liquid crystal layer contains a photoisomerizable compound on the surface opposite to the polymer film side.

12. The polarizing plate with a pressure-sensitive adhesive layer according to claim 1, wherein the angle between the absorption axis of the polarizer and the in-plane slow axis of the positive A plate is 45±10°, and the in-plane retardation of the positive A plate at a wavelength of 550 nm is 120 to 170 nm.

13. The polarizing plate with a pressure-sensitive adhesive layer according to claim 1, wherein the polarizer and the positive A plate are laminated together via a polyvinyl alcohol-based adhesive.

14. The polarizing plate with a pressure-sensitive adhesive layer according to claim 1, wherein the positive A plate is a layer obtained by curing a composition containing a polymerizable liquid crystal compound and a polymer having a group represented by formula (1). Formula (1) *-B-(OR ｘ１ ) ２ R ｘ１ each independently represents a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group, and two R ｘ１ may be linked to each other via an alkylene linking group, an arylene linking group, or a linking group consisting of a combination thereof.

15. The polarizing plate with a pressure-sensitive adhesive layer according to claim 1, wherein the polarizer and the positive A plate are laminated together via an adhesive layer formed by curing an ultraviolet-curable adhesive.

16. A polarizing plate with a pressure-sensitive adhesive layer according to claim 8, wherein the polymer film includes a region A containing a component derived from a liquid crystal compound contained in the vertically aligned liquid crystal layer, and the thickness of the region A is 20 to 200 nm.

17. A display device comprising a polarizing plate with an adhesive layer according to any one of claims 1 to 16.

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