JP2025113364A - Polarizing plate with adhesive layer, display device - Google Patents

Abstract

To provide a polarizing plate with an adhesive layer and a display device that are less likely to curl.SOLUTION: A 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 this order; and an adhesive layer which is arranged on the positive C plate side of the polarizing plate. The positive A plate is a layer that is obtained by hardening a polymerizable liquid crystal compound, and the thickness of the positive C plate is 20.0 - 70.0 μm.SELECTED DRAWING: None

Description

The present invention relates to a polarizing plate with an adhesive layer and a display device.

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

International Publication No. 2023/276611

As one of the usage forms of a polarizing plate, it is desirable to use the polarizing plate as a polarizing plate with an adhesive layer by disposing an adhesive layer on one surface of the polarizing plate.
The present inventors fabricated a polarizing plate with an adhesive layer by placing an adhesive layer on one surface of a polarizing plate as disclosed in Patent Document 1, but found that the polarizing plate with the adhesive layer curled, making it difficult to attach to an object to be attached.

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.

The inventors conducted extensive research to solve the above problems and have completed the present invention, which has the following configuration.

The inventors have discovered that the above problem can be solved by the following configuration.

(1) A polarizing plate having a protective film, a polarizer, a positive A plate, and a positive C plate in this order;
a pressure-sensitive 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,
A polarizing plate with an adhesive layer, wherein the thickness of the positive C plate is 20.0 to 70.0 μm.
(2) The polarizing plate with a pressure-sensitive adhesive layer according to (1), wherein when the polarizing plate with a pressure-sensitive adhesive layer is bonded to a glass substrate via a pressure-sensitive adhesive and a cross-cut test of 100 squares is performed on the bonded polarizing plate with a pressure-sensitive 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 (1) or (2), 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 a pressure-sensitive adhesive layer according to any one of (1) to (3), wherein the positive C plate contains 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 at a wavelength of 550 nm of −100 to 30 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 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 (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 angle between the absorption axis of the polarizer and the in-plane slow axis of the positive A plate is 45±10°,
The polarizing plate with a pressure-sensitive adhesive layer according to any one of (1) to (11), wherein the positive A plate has an in-plane retardation of 120 to 170 nm at a wavelength of 550 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 pressure-sensitive 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 later.
(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 formed by curing an ultraviolet-curable adhesive.
(16) The polarizing plate with a pressure-sensitive adhesive layer according to any one of (8) to (14), wherein the polymer film includes a region A containing a liquid crystal-derived component 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 the pressure-sensitive adhesive layer according to any one of (1) to (16).

According to the present invention, it is possible to provide a polarizing plate with a pressure-sensitive adhesive layer in which curling is suppressed.
The present invention also provides a display device.

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

The present invention will be described in detail below.
The following description of the components 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.

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

In this specification, Re(λ) and Rth(λ) respectively represent the in-plane retardation and the thickness retardation at a wavelength λ, which is 550 nm unless otherwise specified.
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 the film thickness (d) into AxoScan, the following can be calculated:
In-plane slow axis direction (°)
Re(λ)=R0(λ)
Rth(λ)=((nx+ny)/2-nz)×d
is calculated.
Note that R0(λ) is displayed as a numerical value calculated by AxoScan, but it means Re(λ).

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.
Alternatively, values from the Polymer Handbook (John Wiley & Sons, Inc.) and catalogs of various optical films can 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).

In this specification, the A plate and the C plate 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 value, and the negative A plates have a negative Rth value.
Formula (A1) nx>ny≒nz
Formula (A2) ny<nx≒nz
The above "≒" encompasses not only the case where the two are completely identical, but also the case where the two are substantially identical. For example, "substantially the same" means that "ny ≒ nz" also includes the case 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 the case 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 and negative C plates. The positive C plate satisfies the relationship of formula (C1), and the negative C plate satisfies the relationship of formula (C2). The positive C plate has a negative Rth value, while the negative C plate has a positive Rth value.
Formula (C1) nz>nx≒ny
Formula (C2) nz<nx≒ny
The above "≒" includes not only the case where the two are completely identical, but also the case where the two are substantially identical. For example, "substantially the same" also includes 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."

A characteristic feature of the polarizing plate with a pressure-sensitive adhesive layer of the present invention is that it uses a positive C plate with a predetermined thickness.
One of the reasons why conventional polarizing plates with a pressure-sensitive adhesive layer tend to curl is that the positive A plate included in the polarizing plate with a pressure-sensitive adhesive layer 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 polarizing plate with a pressure-sensitive adhesive layer 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.

FIG. 1 shows an example of the polarizing plate with a pressure-sensitive adhesive layer of the present invention.
As shown in Fig. 1, the polarizing plate 10 with a pressure-sensitive adhesive layer has, in this order, a polarizing plate 12 and a pressure-sensitive adhesive layer 22. The polarizing plate 12 has, in this order, a protective film 14, a polarizer 16, a positive A plate 18, and a positive C plate 20. 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 on the positive C plate 20 side.
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 another layer, but as will be described later, they may be laminated via another layer (for example, an adhesive layer).
Each member included in the pressure-sensitive adhesive layer-attached polarizing plate 10 will be described in detail below.

<Protective film>
The protective film is a film that protects the 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, the term "transparent" refers to a visible light transmittance of 60% or more, preferably 80% or more, and more preferably 90% or more. There is no particular upper limit, but it is often less than 100%.

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-based resins, and polystyrene-based 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, and more specifically, includes cycloolefin polymer (COP) and cycloolefin copolymer (COC).
As the hard coat layer, a known layer can be used, for example, a layer obtained by polymerizing and curing a polyfunctional monomer.

There are no particular restrictions on the thickness of the protective film, but in order to make the polarizing plate thinner, it is preferably 40 μm or less, and more preferably 25 μm or less. There is no particular lower limit, but it is often 10 μm or more.

<Polarizer>
The polarizer may be any member that has the function of converting natural light into specific linearly polarized light, and examples thereof include an absorptive polarizer.
The type of polarizer is not particularly limited, and any commonly used polarizer can be used, such as an iodine-based polarizer, a dye-based polarizer using a dichroic material, and a polyene-based polarizer. 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.

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 substance is not particularly limited, and examples thereof include visible light absorbing substances (dichroic dyes), luminescent substances (fluorescent substances, phosphorescent substances), ultraviolet absorbing substances, infrared absorbing substances, nonlinear optical substances, carbon nanotubes, and inorganic substances (e.g., quantum rods), and any conventionally known dichroic substance (dichroic dye) can be used.

The luminosity-corrected single transmittance of the polarizer is not particularly limited, but is preferably 42% or more, more preferably 43% or more, in terms of achieving better effects of the present invention. The upper limit is not particularly limited, but is preferably 48% or less.
The visibility-corrected single transmittance is calculated by the following method.
For the polarizer, the transmittance (T1) in the absorption axis direction and the transmittance (T2) in the direction perpendicular to the absorption axis in the wavelength range of 380 to 780 nm are measured 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 unit transmittance (%) = (T1 + T2) / 2
The obtained single transmittance is subjected to luminosity correction using a 2-degree visual field (C light source) according to JIS Z 8701:1999 "Method of displaying color - XYZ color system and X10Y10Z10 color system" to determine the luminosity-corrected single transmittance.

There are no particular restrictions on the thickness of the polarizer, but in order to be able to reduce the thickness of the polarizing plate, it is preferably 40 μm or less, and more preferably 25 μm or less. There is no particular lower limit, but it is often 5 μm or more.

<Positive A Plate>
The definition of the positive A plate is as described above.
The in-plane retardation Re(550) 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 the polarizing plate of the present invention with superior properties as a circular polarizing plate.

A positive A plate may exhibit either forward wavelength dispersion (the property in which in-plane retardation decreases as the measured wavelength increases) or reverse wavelength dispersion (the property in which in-plane retardation increases as the measured wavelength increases). It is preferable that the forward wavelength dispersion and reverse wavelength dispersion be exhibited in the visible light range.

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

The polymerizable liquid crystal compound is a liquid crystal compound having a polymerizable group.
As the polymerizable liquid crystal compound, known compounds can be used.
Examples of the polymerizable rod-like liquid crystal compound include the compounds described in claim 1 of JP-A No. 11-513019 and in paragraphs 0026 to 0098 of JP-A No. 2005-289980.
In this specification, the type of polymerizable group is not particularly limited, and is preferably a functional group capable of undergoing an addition polymerization reaction, more preferably a polymerizable ethylenically unsaturated group or a ring-polymerizable group, and still more preferably a (meth)acryloyl group, a vinyl group, a styryl group, or an allyl group.

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 preferable that the layer has no fluidity and the alignment state is not changed by an external field or external force, usually in a temperature range of 0 to 50°C, or under more severe conditions, in a temperature range of -30 to 70°C, and that the fixed alignment state can be stably maintained.

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 a polarizing plate of the present invention with superior properties as a circular polarizing plate.

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 mean. The thickness can be measured using, for example, a reflection spectroscopic film thickness meter FE3000.

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.

By using a polymer having a group represented by formula (1), the adhesion between the positive A plate and the water-based adhesive disposed adjacent to the positive A plate is improved.
Formula (1) *-B-(OR ^x1 ) ₂
Each R ^x1 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 formed by a combination thereof.

The substituted or unsubstituted aliphatic hydrocarbon group includes 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.

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).

The definition of R ^x1 is as described above.
R ^x2 and R ^x3 each independently represent a hydrogen atom or an alkyl group.
The number of carbon atoms in the alkyl group is not particularly limited, but is preferably 1 to 18.
The alkyl group may have any of a straight-chain, branched-chain, and cyclic structure.

R ^x4 represents a hydrogen atom or a substituent.
Substituents include hydroxy groups, alkyl groups, alkenyl groups and aryl groups.

^Lx represents a divalent linking group.
The divalent linking group is not particularly limited, and examples thereof include an alkylene group (preferably an alkylene group having 1 to 20 carbon atoms), an arylene group, —O—, —S—, —CO—, —SO—, —SO ₂ —, —NR ^a —, and a divalent linking group formed by combining two or more of these, where R ^a represents a hydrogen atom or an alkyl group.
Among these, -alkylene group-O-(arylene group-CO-O) _nx -arylene group-, where nx represents an integer of 0 to 2, is preferred as the divalent linking group.

The content of repeating units having a group represented by formula (1) is preferably 5 to 30% by mass of all repeating units contained in the polymer.

The polymer may contain repeating units 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).

R ^y1 to R ^y3 each independently represent an alkyl group, an alkenyl group, an aryl group, or an alkylenearyl group.
Examples of the alkyl group include linear alkyl groups having 1 to 18 carbon atoms, branched alkyl groups having 3 to 18 carbon atoms, and cyclic alkyl groups.
The alkenyl group includes alkenyl groups having 2 to 12 carbon atoms.
The aryl group includes an aryl group having 6 to 12 carbon atoms, specifically, a phenyl group, an α-methylphenyl group, and a naphthyl group.
The alkylenearyl group includes alkylenearyl groups having 7 to 30 carbon atoms.

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).

The definitions of R ^y1 to R ^y3 are as described above.
R ^y4 and R ^y5 each independently represent an alkyl group.
The number of carbon atoms in the alkyl group is not particularly limited, but is preferably 1 to 18.
The alkyl group may have any of a straight-chain, branched-chain, and cyclic structure.

R ^y6 represents a hydrogen atom or a substituent.
Substituents include hydroxy groups, alkyl groups, alkenyl groups and aryl groups.

L ^y1 represents a single bond or an alkylene group having 1 to 6 carbon atoms. L ^y2 represents a ny+1 valent linking group having no fluorine atoms.
The ny+1-valent linking group represented by L ^y2 that does not have a fluorine atom is, for example, preferably a ny+1-valent hydrocarbon group having 1 to 15 carbon atoms that may have a substituent other than a fluorine atom, in which some of the carbon atoms that make up the hydrocarbon group may be substituted with a heteroatom. For example, of the —CH ₂ — groups that make up part of the ny+1-valent hydrocarbon group, one or two or more non-adjacent —CH ₂ — groups may each independently be 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).

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

The content of repeating units having a group represented by formula (2) is preferably 25 to 65% by mass of all repeating units contained in the polymer.

The polymer preferably contains a repeating unit having a polymerizable group.
The polymerizable group is as described above.
Examples of the repeating unit having a polymerizable group include a repeating unit represented by formula (Z).

R ^z1 and R ^z2 each independently represent a hydrogen atom or an alkyl group.
The number of carbon atoms in the alkyl group is not particularly limited, but is preferably 1 to 18.
The alkyl group may have any of a straight-chain, branched-chain, and cyclic structure.

R ^z3 represents a hydrogen atom or a substituent.
Substituents include hydroxy groups, alkyl groups, alkenyl groups and aryl groups.

^Lz represents a divalent linking group.
The divalent linking group is not particularly limited, and examples thereof include an alkylene group (preferably an alkylene group having 1 to 20 carbon atoms), an arylene group, —O—, —S—, —CO—, —SO—, —SO ₂ —, —NR ^a —, and a divalent linking group formed by combining two or more of these, where R ^a represents a hydrogen atom or an alkyl group.

R ^z4 represents a polymerizable group.

The content of repeating units having a polymerizable group is preferably 5 to 40% by mass of all repeating units contained in the polymer.

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

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

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

The configuration of the positive C plate is not particularly limited, and examples thereof include a vertically aligned liquid crystal layer (a layer formed by fixing vertically aligned rod-like liquid crystal compounds) and a polymer film, and a laminate of a vertically aligned liquid crystal layer and a polymer film is preferred in terms of achieving better effects of the present invention. In other words, 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 order to obtain better adhesion between the vertically aligned liquid crystal layer and the polymer film, it is preferable that the vertically aligned liquid crystal layer and the polymer film are in direct contact with each other.
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. However, 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 a vertically aligned polymerizable rod-like liquid crystal compound by polymerization.

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 liquid crystal-derived component contained in the vertically aligned liquid crystal layer. From the viewpoints of adhesion and alignment of the vertically aligned liquid crystal layer, the thickness of Region A is preferably 20 to 200 nm. Region A preferably contains a vertically aligned liquid crystal compound.
Methods for controlling the thickness of region A include controlling it by adjusting the type of solvent or solid concentration of the composition forming the vertically aligned liquid crystal layer, controlling it by incorporating a crosslinkable polymer or vertical alignment agent described below into the vertically aligned liquid crystal layer, and controlling it by the drying or heating conditions of the vertically aligned liquid crystal layer.
Whether or not a polymer film contains a region A containing a liquid crystal-derived component contained in the vertically aligned liquid crystal layer can be confirmed by performing 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, measuring the secondary ion intensity of the component derived from the liquid crystal of the vertically aligned liquid crystal layer, and checking whether the secondary ion intensity I of the component derived from the liquid crystal 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 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)

As the rod-shaped liquid crystal compound, known compounds can be used.
Examples of the rod-shaped liquid crystal compound include the rod-shaped liquid crystal compounds exemplified for the positive A plate.

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.

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 that curling is more effectively suppressed.
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 of the measured thicknesses. The thickness can be measured using, for example, a reflection spectroscopic film thickness meter FE3000.

One of the preferred embodiments 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 may be a known resin. More specifically, the resin may be a cellulose-based resin (hereinafter also referred to as cellulose acylate) typified by triacetyl cellulose, a norbornene-based resin (such as Zeonex and Zeonor manufactured by Nippon Zeon Co., Ltd., and Arton manufactured by JSR Corporation), an acrylic resin, a polyester-based resin, or a polystyrene-based resin. Among these, the polymer film is preferably a film containing a cellulose-based resin, and more preferably a cellulose acylate film.

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 that the polarizing plate of the present invention is superior as a 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 polarizing plate of the present invention with superior properties as a circular polarizing plate. The lower limit is not particularly limited, and is 0 nm.

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 that curling is further suppressed.
The thickness of the polymer film refers to the average thickness of the polymer film, which is determined by measuring the thickness of any five or more points on the polymer film and calculating the arithmetic average.

As described above, the vertically aligned liquid crystal layer is a layer in which vertically aligned rod-like liquid crystal compounds are fixed.
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 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 a crosslinked material obtained by crosslinking a polymer having a crosslinkable group, as described below.
Examples of the crosslinkable group include the polymerizable groups described above.
In addition, the cross-linked material being concentrated 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 cross-linked material in the divided region on the polymer film side is greater than the content of the cross-linked material in the divided region on the opposite side to the polymer film side.

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.

The crosslinkable polymer preferably contains a repeating unit having a crosslinkable group.
As described above, the crosslinkable group is preferably a polymerizable group, 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 formula (Z).

From the viewpoint of distributing the crosslinked material unevenly on the polymer film side, it is preferable that the crosslinkable polymer does not contain fluorine atoms, silicon atoms, or photoalignable groups (e.g., cinnamoyl groups or azo groups). In other words, it is preferable that the crosslinked material formed by crosslinking the crosslinkable polymer does not contain fluorine atoms, silicon atoms, or photoalignable groups.

The content of repeating units having crosslinkable groups is preferably 50 to 99% by mass of all repeating units contained in the crosslinkable polymer.

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, but 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% by mass based on the total repeating units contained in the crosslinkable polymer.

The crosslinkable polymer may have a repeating unit other than the repeating units 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.

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

Specific examples of crosslinkable polymers include, but are not limited to, the structures below. The repeating units a to c represent the content (mass %) of each repeating unit relative to the total repeating units.

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

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

The vertically aligned liquid crystal layer preferably contains a photoisomerizable compound on the surface opposite to the polymer film side. As will be described later, by containing the photoisomerizable compound in the vertically aligned liquid crystal layer, a positive A plate can be formed directly on the vertically aligned liquid crystal layer, and the adhesion between the vertically aligned liquid crystal layer and the positive A plate can be improved.
The photoisomerizable compound is not particularly limited as long as it is a compound that can be photoisomerized, and examples thereof include compounds having a photoisomerizable group, such as 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 based on the total repeating units contained in the photoisomerizable compound.

The photoisomerizable compound preferably contains a repeating unit having a 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% by mass based on the total repeating units contained in the photoisomerizable compound.

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 curling.
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 of the measured thicknesses. The thickness can be measured using, for example, a reflection spectroscopic film thickness meter FE3000.

When the vertically aligned liquid crystal layer is in direct contact with the positive A plate, from the viewpoint of adhesion, it is preferable that the vertically aligned liquid crystal layer contains a region (referred to as region B) containing the liquid crystal-derived component contained in the positive A plate. The thickness of region B is preferably 5 to 100 nm.
The measurement method for the region B may be the same as that for the region A.

<Adhesive Layer>
The pressure-sensitive adhesive layer is a layer formed using a pressure-sensitive 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-based adhesives) are preferred.
As the acrylic pressure-sensitive adhesive, a copolymer of a (meth)acrylate in which the alkyl group in the ester moiety is an alkyl group having 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.
Polyvinyl alcohol-based adhesives include adhesives made of polyvinyl alcohol or its derivatives. Polyvinyl alcohol derivatives include polyvinyl formal and polyvinyl acetal. Other examples include those modified with olefins such as ethylene and propylene, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and their alkyl esters, or acrylamide.

The thickness of the adhesive layer is not particularly limited, but is preferably 1 to 30 μm, and more preferably 5 to 25 μm.

<Other demographics>
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 polarizing plate with a pressure-sensitive adhesive layer of the present invention may further have an adhesive layer in order to enhance the adhesiveness between members.

The adhesive 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 by curing an adhesive.
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 adhesive 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 the curable component in the (meth)acrylate adhesive include a compound having a (meth)acryloyl group and a compound having a vinyl group.

There are no particular restrictions on the thickness of the adhesive layer, but a thickness of 0.1 to 5 μm is preferred, and 0.5 to 2 μm is more preferred.

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.

In particular, it is preferable that the polarizer and the positive A plate are laminated via a pressure-sensitive adhesive layer, and it is more preferable that they are laminated via a polyvinyl alcohol-based pressure-sensitive adhesive.
It is also preferable that the polarizer and the positive A plate are laminated via an adhesive layer formed by curing an ultraviolet-curable adhesive.

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

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 of 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 the polymer film is laminated with good adhesion to the adjacent layer, and therefore peeling is unlikely to occur 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 carried out in accordance with JIS-K5600-5-6 (1999).

<Method of manufacturing a polarizing plate with a pressure-sensitive adhesive layer>
The method for producing the pressure-sensitive adhesive layer-attached polarizing plate of the present invention is not particularly limited, and the plate can be produced by a known method.
For example, a 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 an adhesion layer. More specifically, a polarizing plate may be manufactured by laminating a protective film on one surface side of the polarizer while transporting the polarizer, and a laminate film including a positive A plate and a positive C plate on the other surface side of the polarizer, and then disposing the pressure-sensitive adhesive layer on the positive C plate side of the obtained polarizing plate.

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 film to an alignment treatment to align the polymerizable liquid crystal compound in the coating film, and then subjecting the coating film to a curing treatment.
The 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.

The composition may be applied to a substrate having an alignment film, which may be a photo-alignment film.
Methods for applying the composition include curtain coating, dip coating, spin coating, print coating, spray coating, slot coating, roll coating, slide coating, blade coating, gravure coating, and wire bar coating.

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 changing the composition ratio, such as the amount of solvent.
The conditions for heating the coating 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.

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 treatment and heat treatment. Among these, from the viewpoint of manufacturability, light irradiation treatment is preferred, and ultraviolet irradiation treatment is more preferred.
The irradiation conditions for the light irradiation treatment are not particularly limited, but the irradiation dose is preferably 50 to 1000 mJ/cm ² .
The atmosphere during the light irradiation treatment is not particularly limited, but a nitrogen atmosphere is preferred.

As a method for producing a positive C plate, a method using a composition containing a polymerizable liquid crystal compound can be mentioned, 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.
When the positive C plate includes a vertically aligned liquid crystal layer and a polymer film, the above composition may be applied onto the polymer film to form the vertically aligned liquid crystal layer.

In the present invention, a composition for forming a positive A plate may be applied onto a positive C plate to form a positive A plate that is directly laminated on the positive C plate.
In the above-mentioned procedure, a photoisomerizable compound is disposed on the surface of the positive C plate on which the positive A plate is 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 to 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.

<Application>
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 can be suitably used for antireflection purposes 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 the polarizing plate with a pressure-sensitive adhesive layer of the present invention is applied to a display device, the display device and the polarizing plate with a pressure-sensitive adhesive layer may be attached together with the pressure-sensitive adhesive layer of the polarizing plate with a pressure-sensitive adhesive layer facing the display device.
The display element is not particularly limited, and examples thereof include an organic electroluminescence display element and a liquid crystal display element.

The following examples and comparative examples will further illustrate the features of the present invention. The materials, amounts used, ratios, processing details, and processing procedures shown in the following examples can be modified 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.

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 with an average pore size of 34 μm and a sintered metal filter with an average pore size of 10 μm to prepare a dope. The dope had a solids concentration of 23.5% by mass and contained a solvent of methylene chloride/methanol/butanol in a mass ratio of 81/18/1.

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Cellulose acylate dope -----------------------------------------------------------------
Cellulose acylate (acetyl substitution degree 2.86, viscosity average polymerization degree 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 parts by mass of solvent (methylene chloride/methanol/butanol)
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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 the resulting web (film) was then peeled off. The drum was made of SUS.

The web (film) obtained by casting was peeled from the drum and then dried for 20 minutes in a tenter apparatus, in which both ends of the web were clipped with clips while the film was being transported, at 30 to 40°C. Subsequently, the web was post-dried by zone heating while being transported with rolls. The obtained web was knurled and then wound up to prepare a cellulose acylate film (1) having 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.

(Formation of Positive C Plate (1A))
A composition (1A) for forming a vertically aligned liquid crystal layer containing a rod-shaped liquid crystal compound having the following composition was applied to the cellulose acylate film (1) using a Giesser coater to form a composition layer. The film with the composition layer formed thereon was heated with warm air at 60°C for 1 minute, and then irradiated with ultraviolet light at an exposure dose of 100 mJ/ ^cm2 using a 365 nm UV-LED while purging with nitrogen to maintain an oxygen concentration of 100 ppm by volume or less. The resulting coating film was then annealed with warm 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 (1).
The end of the positive C-plate (1A) is
The positive C plate (1A) had an in-plane retardation Re of 0 nm at a wavelength of 550 nm and a thickness direction retardation Rth of −85 nm at a wavelength of 550 nm. The average tilt angle of the long axis direction of the rod-like liquid crystal compound with respect to the film plane was 90°, and it was confirmed that the rod-like liquid crystal compound was aligned perpendicular to the film plane.

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Composition for forming a vertically aligned liquid crystal layer (1A)
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100 parts by mass of rod-shaped liquid crystal compound (A) below, 4.2 parts by mass of polymerizable monomer (A-400, manufactured by Shin-Nakamura Chemical Co., Ltd.), 5.1 parts by mass of polymerization initiator S-1 (oxime type) below, 3.0 parts by mass of photoacid generator D-1 below, 4.0 parts by mass of polymer M-1 below, 1.9 parts by mass of alignment control agent A-1 below, 0.8 parts by mass of photoalignment polymer PA-1 below, 0.2 parts by mass of diisopropylethylamine, 93.8 parts by mass of methyl ethyl ketone, 372.0 parts by mass of methyl isobutyl ketone

Rod-shaped liquid crystal compound (A) (hereinafter referred to as a compound mixture. The numbers represent the mass ratio.)

Polymerization initiator S-1

Photoacid generator D-1

Polymer M-1 (weight-average molecular weight was 52,000. The values listed for repeating units represent the content (mass%) of each repeating unit relative to the total repeating units.)

Alignment control agent A-1

Photoalignable polymer PA-1 (The numerical values listed for the repeating units represent the content (mass%) of each repeating unit relative to the total repeating units. Weight-average molecular weight: 90,000. Me represents a methyl group.)

(Preparation of Positive A Plate (1B))
The vertically aligned liquid crystal layer (1A) side of the long positive C plate (1A) was irradiated with UV light (ultra-high pressure mercury lamp; UL750; manufactured by HOYA) at 7.9 mJ/cm ² (wavelength: 313 nm) through a wire grid polarizer to form a composition layer with alignment controllability on the surface. Subsequently, a horizontally aligned liquid crystal layer forming composition (1B) containing a rod-shaped liquid crystal compound of the following composition was applied to the vertically aligned liquid crystal layer (1A) using a Giesser coater, and the composition was heated to 120°C with hot air and then cooled to 60°C to stabilize the alignment. Thereafter, the film was heated to 60°C using an ultra-high pressure mercury lamp in a nitrogen atmosphere (oxygen concentration less than 100 ppm) and subjected to a first UV irradiation (80 mJ/cm ² ), followed by a second UV irradiation (300 mJ/cm ² ) at 100°C to fix the alignment, thereby forming a positive A plate (1B). The edges of the positive A plate (1B) were formed 10 mm inward from the edges of the cellulose acylate film.
The positive A plate (1B) had a thickness of 2.8 μm and an Re(550) of 141 nm at a wavelength of 550 nm. When the width direction of the film was set to 0° (the longitudinal direction was set to 90°), the in-plane slow axis direction (the orientation axis angle of the liquid crystal compound) was 45°.

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Composition for forming horizontally aligned liquid crystal layer (1B)
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8.5 parts by mass of the following rod-shaped liquid crystal compound (B): 8.5 parts by mass of the following rod-shaped liquid crystal compound (C): 45.0 parts by mass of the following rod-shaped liquid crystal compound (D): 32.0 parts by mass of the following rod-shaped liquid crystal compound (E): 6.0 parts by mass of the following rod-shaped liquid crystal compound (F): 0.5 parts by mass of the above polymerization initiator S-1 (oxime type): 0.1 parts by mass of the following leveling agent L-1: 233.2 parts by mass of tetrahydrofuran: 58.3 parts by mass of cyclopentanone: 12.0 parts by mass of methylthiobenzothiazole

Rod-shaped liquid crystal compound (B)

Rod-shaped liquid crystal compound (C)

Rod-shaped liquid crystal compound (D)

Rod-shaped liquid crystal compound (E)

Rod-shaped liquid crystal compound (F)

Leveling agent L-1 (weight average molecular weight was 28,500. The values listed for the repeating units represent the content (mass%) of each repeating unit relative to the total repeating units.)

Using the above procedure, a long laminated film (1) with a thickness of 43.5 μm was produced in which a positive C plate (1A) and a positive A plate (1B) were directly laminated together.

(Preparation of Water-Based Adhesive 1)
Aqueous adhesive 1 was prepared by adding 3 parts of a carboxyl group-modified polyvinyl alcohol (Kuraray Poval KL318, manufactured by Kuraray Co., Ltd.) and 1.5 parts of a water-soluble polyamide epoxy resin (Sumirez Resin 650, manufactured by Taoka Chemical Co., Ltd., an aqueous solution with a solids concentration of 30%) to 100 parts of water.

(Preparation of 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.

(Preparation of Polarizer 1)
A polyvinyl alcohol film having a thickness of 20 μm, a degree of polymerization of 2,400, and a degree of saponification of 99.9% or more was uniaxially stretched in a dry state to a stretching ratio of 4.5 times, and while maintaining the tension, it was immersed for 60 seconds in a dye bath at 28° C. containing 0.05 parts by weight of iodine and 5 parts by weight of potassium iodide per 100 parts by weight of water.

Then, it was immersed for 110 seconds in boric acid aqueous solution 1 at 64°C, which contained 2.3 parts by weight of boric acid and 15 parts by weight of potassium iodide per 100 parts by weight of water. It was then immersed for 30 seconds in boric acid aqueous solution 2 at 67°C, which contained 5.5 parts by weight of boric acid and 15 parts by weight of potassium iodide per 100 parts by weight of water. It was then washed with pure water at 10°C and dried to obtain polarizer 1. The boron content of polarizer 1 was 2.76% by weight. The polarizer had a thickness of 8 μm.

(Preparation of Polarizing Plate (P1))
The surface of a support of 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 washing 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 washing bath at room temperature and further dried with hot air at 100° C. to obtain a polarizer protective film (1).
A polarizer protective film (1) was bonded to one side of a polarizer 1 using nip rolls with the aqueous adhesive 1 interposed therebetween to obtain a linear polarizing plate. The positive A plate (1B) surface of the laminate film (1) was bonded to the other side of the polarizer of the linear polarizing plate using nip rolls with the aqueous adhesive 1 interposed therebetween. The edges of the aqueous adhesive 1 were positioned 15 mm inward from the edges of the cellulose acylate film. Next, 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). Then, the adhesive layer formed on the separator film was bonded to the laminate film (1). Using the above procedure, a polarizing plate (P1) with an adhesive layer was produced.
At this time, the laminate film, polarizer protective film (1), aqueous adhesive 1, polarizer (1), aqueous adhesive 1, positive A plate (1B), positive C plate (1A) (vertical alignment liquid crystal layer (1A), cellulose acylate film (1)), adhesive, 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°.

Example 2
A polarizing plate (P2) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the positive A plate (1B) surface of the laminated film (1) was subjected to corona treatment (60 Wmin/m ² ) before lamination.

Example 3
A polarizing plate (P3) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the positive A plate (1B) surface of the laminated film (1) was subjected to plasma treatment by the following method before lamination.
(Plasma treatment)
The plasma treatment was carried out using an apparatus having a configuration similar to that of the plasma generation apparatus described in Example 1 of JP 2018-170183 A. In the plasma generation apparatus, helium gas, oxygen gas, and nitrogen gas were introduced between the electrode and the counter electrode at a volumetric flow ratio of 10/0.025/0.5, and 6000 W of power was applied to the electrode to generate plasma between the electrode and the counter electrode.
The transport speed of the laminated film (1) transported between the electrode and the counter electrode was 10.0 m/min. The gas composition of the plasma raw material gas introduced into the plasma generator (analyzed by gas chromatography) was 94.1 vol %/0.4 vol %/5.5 vol % for helium gas, oxygen gas, and nitrogen gas.

Example 4
A polarizing plate (P4) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the aqueous adhesive 1 was changed to the aqueous adhesive 4 described below.
(Preparation of Water-Based Adhesive 4)
Aqueous adhesive 4 was prepared by adding 3 parts of carboxyl group-modified polyvinyl alcohol (Kuraray Poval KL318, manufactured by Kuraray Co., Ltd.) to 100 parts of water.

Example 5
A polarizing plate (P5) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the aqueous adhesive 1 was changed to aqueous adhesive 5 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIRMER (registered trademark) Z-200", a PVA-based resin aqueous solution with a resin concentration of 3% by weight and a moisture content of 97%).

Example 6
A polarizing plate (P6) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 2, except that the water-based adhesive 1 was changed to the water-based adhesive 5.

Example 7
A polarizing plate (P7) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 3, except that the water-based adhesive 1 was changed to the water-based adhesive 5.

Example 8
A polarizing plate (P8) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the water-based adhesive 1 was changed to the water-based adhesive 8 described below.
(Preparation of Water-Based Adhesive 8)
50 g of a modified PVA resin containing acetoacetyl groups ("GOHSENEX Z-410" manufactured by Mitsubishi Chemical Corporation) was dissolved in 950 g of pure water. This solution was heated at 90°C for 2 hours and then cooled to room temperature to obtain PVA solution A for adhesive. Next, PVA solution A, maleic acid, glyoxal, ethanol, and pure water were blended so that the concentrations of each component were as follows (mass %) to prepare water-based adhesive 8.
PVA 3.00%
・Maleic acid 0.01%
・Glyoxal 0.15%
Ethanol 20.00%
・Water 76.84%

Example 9
A polarizing plate (P9) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the aqueous adhesive 1 was changed to the aqueous adhesive 9 described below.
(Preparation of Water-Based Adhesive 9)
100 parts of an acetoacetyl group-containing polyvinyl alcohol resin (average polymerization degree: 1200, saponification degree: 98.5 mol%, acetoacetyl group modification degree: 5 mol%) was dissolved in pure water at 30°C to prepare an aqueous solution with a solids concentration of 3.2 wt%. This was designated as Water-based Adhesive 9.

Example 10
A polarizing plate (P10) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the aqueous adhesive 1 was changed to the aqueous adhesive 10 described below.
(Preparation of Water-Based Adhesive 10)
Aqueous adhesive 10 was obtained by mixing 6.02 parts of acetoacetyl-modified PVA (degree of polymerization 1200, degree of acetoacetyl modification 4.6%, degree of saponification 99.0 mol% or more, solids concentration 4%, manufactured by Mitsubishi Chemical Corporation, trade name "GOHSENEX Z-200"), 25 parts of an aqueous solution containing positively charged alumina colloid (average particle diameter 15 nm) at a solids concentration of 3.2%, and 18.98 parts of pure water.

Example 11
A polarizing plate (P11) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the water-based adhesive 1 was changed to the water-based adhesive 11 described below.
(Preparation of Water-Based Adhesive 11)
100 parts of an acetoacetyl group-containing polyvinyl alcohol resin (average degree of polymerization: 1200, degree of saponification: 98.5 mol%, degree of acetoacetylation: 5 mol%) was dissolved in pure water at 30°C to prepare an aqueous solution adjusted to a solids concentration of 3.7%. 18 parts of an aqueous alumina colloid solution (average particle size 15 nm, solids concentration 10%, positive charge) was added to 100 parts of the aqueous solution to prepare aqueous adhesive 11.

Example 12
A polarizing plate (P12) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the water-based adhesive 1 was changed to the water-based adhesive 12 described below.
(Preparation of Water-Based Adhesive 12)
A water-based adhesive 12 was prepared by dissolving 100 parts by weight of PVA resin (Ecomati manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and 35 parts by weight of a crosslinking agent (Watersol manufactured by Dainippon Ink and Chemicals, Inc.) in 3,760 parts by weight of pure water.

Example 12
A polarizing plate (P12) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the water-based adhesive 1 was changed to the water-based adhesive 12 described below.
(Preparation of Water-Based Adhesive 12)
A water-based adhesive 12 was prepared by dissolving 100 parts by weight of PVA resin (Ecomati manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and 35 parts by weight of a crosslinking agent (Watersol manufactured by Dainippon Ink and Chemicals, Inc.) in 3,760 parts by weight of pure water.

Example 13
A polarizing plate (P13) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the water-based adhesive 1 was changed to the water-based adhesive 13 described below.
(Preparation of Water-Based Adhesive 13)
A water-based adhesive 13 was prepared by dissolving 100 parts by weight of PVA resin (Gosefimer Z: containing acetoacetyl groups, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and 35 parts by weight of a crosslinking agent (Watersol: manufactured by Dainippon Ink and Chemicals, Inc.) in 3,760 parts by weight of pure water.

Example 14
A polarizing plate (P14) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the aqueous adhesive 1 was changed to the aqueous adhesive 14 described below.

(Preparation of PVA solution)
50 g of a modified PVA resin containing acetoacetyl groups (Gohsenex Z-410, manufactured by Mitsubishi Chemical Corporation) was dissolved in 950 g of pure water, heated at 90°C for 2 hours, and then cooled to room temperature to obtain a PVA solution for adhesive.

(Preparation of Antioxidant Solution)
An antioxidant solution was prepared by adding 0.25 g of Irganox 1010 (manufactured by BASF Japan Ltd.), a phenolic antioxidant, to 100 g of ethanol.

(Preparation of Water-Based Adhesive 14)
The PVA solution for adhesive, antioxidant solution, and pure water prepared above were mixed together to give a PVA concentration of 3.0%, an ethanol concentration of 30%, and an Irganox 1010 concentration of 0.075%, to obtain a water-based adhesive 14.

Example 15
A water-based adhesive 15 and a polarizing plate (P15) with a pressure-sensitive adhesive layer were prepared in the same manner as in Example 14, except that the antioxidant solution described in Example 14 was changed to the ultraviolet absorber solution below.
(Preparation of UV absorber solution)
0.25 g of a water-soluble ultraviolet absorber OUV-016 (manufactured by Fujifilm Corporation) was added to 100 g of pure water to prepare an ultraviolet absorber solution.

Example 16
A polarizing plate (P16) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the water-based adhesive 1 was changed to the water-based adhesive 16 described below.
(Preparation of Water-Based Adhesive 16)
An acetoacetyl-modified polyvinyl alcohol resin with a saponification degree of 99.2 mol% (Gohsenol Z200, manufactured by Mitsubishi Chemical Corporation) was dissolved in water (distilled water) to prepare a PVA aqueous solution with a solid content of 8 mass %. The prepared 8 mass % PVA solution was mixed with a 40% aqueous solution of glyoxal as a crosslinking agent in a mass ratio of 3.0:0.7, and the mixture was further adjusted to a total solid content of 3 parts per 100 parts of water, thereby obtaining PVA resin composition A.
Separately, an acetoacetyl-modified polyvinyl alcohol resin with a saponification degree of 99.2 mol% (Gohsenol Z200, manufactured by Mitsubishi Chemical Corporation) was dissolved in water (distilled water) to prepare a PVA aqueous solution with a solid content of 8 mass %. The prepared 8 mass % PVA solution and zinc chloride were mixed in a mass ratio of 3.0:0.09, and the mixture was further adjusted to a total solid content of 3 parts per 100 parts of water, thereby obtaining PVA resin composition B.
The PVA-based resin compositions A and B prepared above were mixed at room temperature in a mass ratio of 1:1 and stirred for 30 minutes to prepare a water-based adhesive 16.

Example 17
A polarizing plate (P17) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the aqueous adhesive 1 was changed to the aqueous adhesive 17 described below.
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Composition of water-based adhesive 17
Polyvinyl alcohol PVA117 (manufactured by Kuraray Co., Ltd.) 2.4 parts by mass Modified polyvinyl alcohol shown below 0.6 parts by mass Isopropyl alcohol 1.6 parts by mass Water 90.0 parts by mass

Example 18
A polarizing plate (P18) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the water-based adhesive 1 was changed to the water-based adhesive 18 described below.
(Preparation of Water-Based Adhesive 18)
(A) A 5 wt % aqueous solution of polyvinyl alcohol with a degree of polymerization of 500 and (B) A 2 wt % aqueous solution of sodium carboxymethyl cellulose were mixed to prepare a water-based adhesive 18. The mixing ratio of (A) to (B) was (A):(B) = 20:1.

Example 19
A polarizing plate (P19) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the water-based adhesive 1 was changed to the water-based adhesive 19 described below.
(Preparation of Water-Based Adhesive 19)
A 4 wt% aqueous solution of polyvinyl alcohol resin (average degree of polymerization: 2000, degree of saponification: 94%, manufactured by Nippon Synthetic Co., Ltd.) containing acetoacetyl groups (5 wt%) was prepared by dissolving it in pure water. A titanium amine complex crosslinker (product name: TYZOR TE, manufactured by DuPont) was added to the solution at a ratio of 6.7 wt. parts per 100 wt. parts of polyvinyl alcohol resin and stirred. A pH adjuster containing 5 wt. parts of glycidyl methacrylate, 28.5 wt. parts of methanol, and 66.5 wt. parts of hydrochloric acid was then prepared. The pH adjuster was then added to the aqueous polyvinyl alcohol resin solution to adjust the pH to 7, producing water-based adhesive 19.

Example 20
A polarizing plate (P20) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the aqueous adhesive 1 was changed to the aqueous adhesive 20 described below.
(Preparation of Water-Based Adhesive 20)
A polyurethane adhesive (A) was prepared by adding 5 parts of a polyfunctional glycidyl ether, CR-5L (manufactured by Dainippon Ink and Chemicals, Inc.), to 100 parts of Hydran AP-20 (manufactured by Dainippon Ink and Chemicals, Inc., solids concentration 30%, viscosity 30 mPa sec), which is an aqueous emulsion of polyester ionomer urethane resin.

Example 21
A polarizing plate (P21) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the water-based adhesive 1 was changed to the water-based adhesive 21 described below.
(Preparation of Water-Based Adhesive 21)
Aqueous adhesive 21 was prepared by blending 100 parts by weight of SE-2716L (manufactured by Taisei Fine Chemical Co., Ltd.) (aqueous solution with a solids concentration of 40%) with 3 parts by weight of epoxy curing agent SR-4GL (manufactured by Sakamoto Pharmaceutical Industry Co., Ltd.) (active ingredient 100%).

Example 22
A polarizing plate (P22) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 20, except that the polarizer protective film (1) was changed to a polarizer protective film (2) (ZEONOR Film manufactured by Optes Co., Ltd.) having a thickness of 40 μm and made of a norbornene-based resin that had been subjected to a corona treatment.

Example 23
A polarizing plate (P23) with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the distance from the edge of the cellulose acylate film to the edge of the water-based adhesive 1 coating was changed to 8 mm.

Example 24
(Preparation of Polarizer 2)
The resin substrate was a long, amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) with a water absorption rate of 0.75% and a Tg of 75°C. One side of the substrate was subjected to a corona treatment, and an aqueous solution containing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (degree of polymerization 1200, degree of acetoacetyl modification 4.6%, degree of saponification 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMER Z200") in a 9:1 ratio was applied to the corona-treated surface and dried at 25°C to form a 13 μm-thick PVA-based resin layer, producing a laminate. The resulting laminate was then free-end uniaxially stretched 2.4 times in the longitudinal direction (longitudinal direction) between rolls operating at different peripheral speeds in a 120°C oven (in-air assisted stretching).
Next, the laminate was immersed in an insolubilizing bath (a boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 30° C. for 30 seconds (insolubilizing treatment).
Next, the polarizing plate was immersed in a dye bath at a liquid temperature of 30° C., while adjusting the iodine concentration and immersion time so that the polarizing plate would have a predetermined transmittance. In this example, the polarizing plate was immersed for 60 seconds in an iodine aqueous solution obtained by blending 0.2 parts by weight of iodine and 1.5 parts by weight of potassium iodide with respect to 100 parts by weight of water (dyeing treatment).
Next, the sample was immersed in a crosslinking bath (a boric acid aqueous solution obtained by mixing 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 30°C for 30 seconds (crosslinking treatment).
Thereafter, the laminate was immersed in an aqueous boric acid solution (an aqueous solution obtained by blending 3 parts by weight of boric acid and 5 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 70°C, and uniaxially stretched in the longitudinal direction (longitudinal direction) between rolls operating at different peripheral speeds so that the total stretching ratio was 5.5 times (underwater stretching).
Thereafter, the laminate was immersed in a cleaning bath (aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) at a liquid temperature of 30° C. (cleaning treatment).
Next, the ultraviolet-curable adhesive shown below was applied to the surface of the PVA-based resin layer of the laminate so that the adhesive layer would have a thickness of 1.0 μm after curing, and a polarizer protective film (3) (a Zeonor-based resin film (thickness 17 μm) manufactured by Zeon Corporation) was laminated thereto. The film was heated to 50°C from the polarizer protective film (3) side using an IR heater, and the adhesive was cured by irradiating it with ultraviolet light shown below. Thereafter, the substrate was peeled from the PVA-based resin layer, and a long single-sided polarizing plate was obtained in which polarizer 2 was laminated onto polarizer protective film (3) via the ultraviolet-curable adhesive. The polarizer 2 had a thickness of 5 μm and a single transmittance of 40.8%.
(Preparation of UV-curable adhesive)
40 parts by weight of N-hydroxyethyl acrylamide (HEAA), 60 parts by weight of acryloylmorpholine (ACMO), and 3 parts by weight of a photoinitiator "IRGACURE 819" (manufactured by BASF) were mixed to prepare an adhesive having a viscosity of 40 mPa·S before curing.
(ultraviolet rays)
As the active energy ray, ultraviolet light (gallium-filled metal halide lamp, irradiation device: Light HAMMER10 manufactured by Fusion UV Systems, Inc., bulb: V bulb, peak irradiance: 1600 mW/cm, cumulative irradiance: 1000/mJ/cm (wavelength: 380 to 440 nm)) was used. The irradiance of ultraviolet light was measured using a Sola-Check system manufactured by Solatell.
(Preparation of polarizing plate (P24))
An aqueous adhesive (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFFIMER (registered trademark) Z-200", a PVA-based resin aqueous solution with a resin concentration of 3% by weight and a moisture content of 97%) was applied to the polarizer (2) surface of the single-sided polarizing plate so that the thickness of the adhesive layer after heating would be 0.1 μm. A laminate film (1) (thickness 43.5 μm) in which the positive C plate (1A) and the positive A plate (1B) described in Example 1 were directly laminated was attached to the resulting film, and the resulting film was heated in an oven maintained at 80° C. for 5 minutes.
Next, a 50 μm thick laminate film made of a PET (polyethylene terephthalate) film with a weak adhesive was attached to the polarizer protective film (3). Then, the adhesive layer formed on the separator film was attached to the laminate film (1). By the above procedure, a polarizing plate (P24) with an adhesive layer was produced.
At this time, the laminate film, polarizer protective film (3), ultraviolet-curable adhesive, polarizer (2), water-based adhesive 24, positive A plate (1B), positive C plate (1A) (vertical alignment liquid crystal layer (1A), cellulose acylate film (1)), adhesive, and separator film were laminated in this order, and the angle formed by the absorption axis of the polarizer (2) and the in-plane slow axis of the positive A plate (1B) was 45°.

<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 of the optically anisotropic layer at a wavelength of 550 nm and the retardation Rth in the thickness direction at a wavelength of 550 nm were determined.

<Measurement of film thickness of laminated film>
The thickness of the laminated film was measured using a contact type film thickness meter.

<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.).

<Measurement of film thickness of laminated films and polymer films>
The thickness of the laminate film and the polymer film was measured using a contact film thickness meter.

<Adhesion evaluation>
The prepared polarizing plate with the adhesive layer was cut into 30 mm x 120 mm strips, and the separator film on the adhesive layer side was peeled off. The exposed 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 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 Corporation) was applied 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: The number of peeled squares is 50 or less. B: The number of peeled squares is 51 or more.

<Evaluation of processing suitability (curl)>
The polarizing plates with pressure-sensitive adhesive layers obtained in each Example and Comparative Example were cut into 200 mm x 200 mm pieces with the MD direction as the diagonal line, 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 the curling of the polarizing plate with pressure-sensitive adhesive layers was suppressed.
A: The polarizing plate is 10 mm or less lifted from the substrate, and can be easily attached.
B: The floating of the polarizing plate from the substrate is more than 10 mm and 20 mm or less, and the polarizing plate can be stuck together.
C: The floating distance of the polarizing plate from the substrate is more than 20 mm and 30 mm or less, and the polarizing plate can be stuck together.
D: The polarizing plate floated from the substrate by more than 30 mm, making lamination difficult.

<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 OLED substrate surface. 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 OLED substrate surface using a roller. The resulting 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: It can be peeled off cleanly without leaving any residue on the glass.
B: Part of the adhesive and the cured liquid crystal film remained on the glass, and when an attempt was made to remove them, the glass broke, so they could not be removed.

<Fabrication of Organic EL Display Device>
(Implementation on a display device)
An Apple iPhone 14 Pro equipped with an organic EL panel was disassembled, and the front glass plate and circular polarizer were removed. Using a SEM-EDX (Hitachi High-Tech SU-8030), it was confirmed that a thin-film encapsulation layer made of silicon nitride (SiN) or silicon oxynitride (SiON) was formed on the surface of the organic EL panel.
The circularly polarizing plate prepared above was attached to the surface of the disassembled organic EL panel via a pressure-sensitive adhesive SK-2057 (manufactured by Soken Chemical & Engineering Co., Ltd.) to prepare a panel for evaluation.

[Evaluation of display performance]
The prepared evaluation panels were observed from the front under bright light, and the coloring was evaluated according to the following criteria. The results are shown in Table 3 below.
A: No visible coloring or only slight coloring (acceptable)
B: Coloring is visible, but the reflected light is small and there is no problem in use (acceptable).

In Table 1, the column "Positive C Film Thickness (μm)" indicates the film thickness (μm) of the positive C plate.
In Table 1, the column "Crosslinkable Polymer" indicates whether or not a cured product of a 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 product of the 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 column "Photoisomerizable compound" indicates whether or not a photoisomerizable compound is contained in the vertically aligned liquid crystal layer, with "A" indicating that a photoisomerizable compound is contained and "B" indicating that a photoisomerizable compound is not contained. In the case of an evaluation of "A," the photoisomerizable compound was present on the surface of the vertically aligned liquid crystal layer opposite to the cellulose acylate film (polymer film) side in 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.

As shown in the table above, the polarizing plate with a pressure-sensitive adhesive layer of the present invention exhibited the desired effects.

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 (17)

a polarizing plate having a protective film, a polarizer, a positive A plate, and a positive C plate in this order;
a pressure-sensitive 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,
The positive C plate has a thickness of 20.0 to 70.0 μm. 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. The polarizing plate with a pressure-sensitive adhesive layer according to claim 1, wherein the positive C plate has a thickness direction retardation of -100 to -30 nm at a wavelength of 550 nm. The polarizing plate with a pressure-sensitive adhesive layer according to claim 1, wherein the positive C plate comprises a polymer film. The polarizing plate with an adhesive layer according to claim 4, wherein the polymer film is a cellulose acylate film. 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. The polarizing plate with a pressure-sensitive adhesive layer according to claim 4, wherein the polymer film has a thickness direction retardation of -100 to 30 nm at a wavelength of 550 nm. 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. 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. 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. 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. the angle between the absorption axis of the polarizer and the in-plane slow axis of the positive A plate is 45±10°,
2. The polarizing plate with a pressure-sensitive adhesive layer according to claim 1, wherein the positive A plate has an in-plane retardation of 120 to 170 nm at a wavelength of 550 nm. The polarizing plate with an adhesive layer according to claim 1, wherein the polarizer and the positive A plate are laminated via a polyvinyl alcohol-based adhesive. 2. 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
Each R ^x1 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 formed by a combination thereof. The polarizing plate with a pressure-sensitive adhesive layer according to claim 1, wherein the polarizer and the positive A plate are laminated via an adhesive layer formed by curing an ultraviolet-curable adhesive. The polarizing plate with a pressure-sensitive adhesive layer according to claim 8, wherein the polymer film includes a region A containing a liquid crystal-derived component contained in the vertically aligned liquid crystal layer, and the thickness of the region A is 20 to 200 nm. A display device comprising a polarizing plate with an adhesive layer according to any one of claims 1 to 16.