Polarizing plate, circular polarizing plate provided with polarizing plate, and display device provided with polarizing plate or circular polarizing plate

Abstract

The invention relates to a polarizing plate, a circular polarizing plate provided with the polarizing plate, and a display device provided with the polarizing plate or the circular polarizing plate. Provided is a polarizing plate having excellent durability under high-temperature and / or high-humidity conditions, in particular excellent adhesion and transmittance. A polarizing plate including a first resin layer and a polarizer adjacent to each other, the first resin layer being a layer of a cured product of a curable resin composition including a monofunctional (meth) acrylate, a polyfunctional (meth) acrylate, and a urethane acrylate, the number of functional groups of the urethane acrylate being 3 or more; the mass ratio of the polyfunctional (meth) acrylate to the monofunctional (meth) acrylate is 1 or more.

Description

Technical Field

[0001] The present invention relates to a polarizing plate, a circularly polarizing plate including the polarizing plate, and a display device including the polarizing plate or the circularly polarizing plate. Background Art

[0002] Polarizing plates have traditionally been used in various image display panels, such as liquid crystal display panels and organic electroluminescent (OLED) display panels, by being bonded to image display elements such as liquid crystal cells or organic EL display elements. In recent years, there has been a growing demand for thinner displays, such as image display panels, and this has led to a demand for even thinner polarizers, one of the components of polarizing plates. To address this demand, for example, a thin guest-host polarizer has been proposed, containing a cured product of a polymerizable liquid crystal compound and a compound exhibiting dichroism. For example, the following patent document discloses a polarizing plate having a protective layer on at least one surface of the guest-host polarizer.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-56834

[0006] Patent Document 2: Japanese Patent Application Publication No. 2018-128573 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] However, conventional polarizing plates may be inferior in durability, particularly adhesion and transmittance, under high-temperature conditions or high-temperature and high-humidity conditions.

[0009] Therefore, an object of the present invention is to provide a polarizing plate having excellent durability under high temperature conditions or high temperature and high humidity conditions, particularly excellent adhesion and transmittance.

[0010] Means for solving problems

[0011] The present inventors have conducted intensive research to solve the above-mentioned problems and have finally completed the present invention. Specifically, the present invention includes the following embodiments.

[0012] [1] A polarizing plate comprising a first resin layer and a polarizer adjacent to each other,

[0013] The first resin layer is a cured product layer of a curable resin composition containing monofunctional (meth)acrylate, polyfunctional (meth)acrylate, and urethane acrylate.

[0014] The number of functional groups of the urethane acrylate is 3 or more,

[0015] The mass ratio of the polyfunctional (meth)acrylate to the monofunctional (meth)acrylate is 1 or more.

[0016] [2] The polarizing plate according to [1], wherein the viscosity of the curable resin composition is 350 cps or less at 25°C.

[0017] [3] The polarizing plate according to [1] or [2], wherein the content of the monofunctional (meth)acrylate in the curable resin composition is 20 parts by mass or more relative to 100 parts by mass of the total of the monofunctional (meth)acrylate, the polyfunctional (meth)acrylate, and the urethane acrylate.

[0018] [4] The polarizing plate according to any one of [1] to [3], wherein the mass ratio of the polyfunctional (meth)acrylate to the monofunctional (meth)acrylate is 2.6 or less.

[0019] [5] The polarizing plate according to any one of [1] to [4], wherein the monofunctional (meth)acrylate contains a monofunctional (meth)acrylate having a hydroxyl group.

[0020] [6] The polarizing plate according to [5], wherein the monofunctional (meth)acrylate having a hydroxyl group is represented by the following formula (1).

[0021] [Chemical Formula 1]

[0022]

[0023] [wherein, n represents an integer from 1 to 12,

[0024] A 1 represents O or NH,

[0025] X 1 represents a methylene group which may have a substituent, and when n is an integer greater than 2, at least one of the methylene groups may be replaced by an oxygen atom, and the substituents may be the same or different.]

[0026] [7] The polarizing plate according to any one of [1] to [6], further comprising a second resin layer adjacent to the polarizer on the side opposite to the first resin layer.

[0027] [8] The polarizing plate according to any one of [1] to [7], further comprising a resin film on the side of the first resin layer opposite to the polarizer.

[0028] [9] The polarizing plate according to any one of [1] to [8], wherein the polarizer is a polarizing film containing a cured layer of a polymerizable liquid crystal composition containing a compound exhibiting dichroism and a polymerizable liquid crystal compound.

[0029]

[10] The polarizing plate according to [9], wherein the cured layer contains 80% by mass or more of a polymerizable liquid crystal compound relative to the total mass of the cured layer,

[0030] The polymer of the polymerizable liquid crystal compound exhibits a smectic liquid crystal phase.

[0031] The compound exhibiting dichroism and the polymer of the polymerizable liquid crystal compound are aligned and contained in the cured product layer.

[0032]

[11] The polarizing plate according to [9] or

[10] , wherein the compound exhibiting dichroism is an azo dye.

[0033]

[12] A circularly polarizing plate comprising the polarizing plate according to any one of [1] to

[11] and a phase difference plate.

[0034]

[13] The circularly polarizing plate according to

[12] , wherein the phase difference plate satisfies the following formula (X).

[0035] Re(450nm) / Re(550nm)<1(X)

[0036] [Where Re(λ) represents the front retardation value for light with a wavelength of λnm]

[0037]

[14] A display device comprising the polarizing plate described in any one of [1] to

[11] , or the circularly polarizing plate described in

[12] or

[13] .

[0038] Effects of the Invention

[0039] According to the present invention, a polarizing plate having excellent durability under high temperature conditions or high temperature and high humidity conditions, particularly excellent adhesion and transmittance, can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a schematic cross-sectional view of a polarizing plate according to one embodiment of the present invention. DETAILED DESCRIPTION

[0041] Hereinafter, embodiments of the present invention will be described in detail. However, the scope of the present invention is not limited to the embodiments described herein, and various modifications can be made without departing from the spirit of the present invention.

[0042] [Polarizing plate]

[0043] The polarizing plate of the present invention comprises a first resin layer and a polarizer adjacent to each other. The first resin layer is a cured layer of a curable resin composition comprising a monofunctional (meth)acrylate, a polyfunctional (meth)acrylate, and a urethane acrylate, wherein the urethane acrylate has three or more functional groups and the mass ratio of the polyfunctional (meth)acrylate to the monofunctional (meth)acrylate is at least one.

[0044] By making the first resin layer adjacent to the polarizer a cured layer of the specific curable resin composition, even when a display device equipped with the polarizing plate is used in a high-temperature environment or a high-temperature, high-humidity environment, the decrease in the adhesion between the first resin layer and the polarizer can be suppressed, and the migration of components contained in the polarizer (such as dichroic compounds) from the polarizer (i.e., diffusion into the first resin layer) can be highly suppressed or reduced. This diffusion can reduce the properties of the polarizer (such as transmittance, polarization degree, etc.). In the polarizing plate of the present invention, this diffusion is highly suppressed or reduced even when the display device is used in a high-temperature, high-humidity environment, resulting in excellent durability (particularly transmittance). As a result, excellent image quality and improved reliability are ensured in the display device equipped with the polarizing plate.

[0045] based on Figure 1 The stacked structure in one embodiment of the polarizing plate is described. The polarizing plate (10) has a structure in which a first resin layer (2) is stacked on one surface of a polarizing plate (1). A second resin layer (3) can be stacked on the other surface of the polarizing plate (1). The polarizing plate (1) can be a single layer consisting only of a cured layer of a polymerizable liquid crystal composition containing a compound exhibiting dichroism and a polymerizable liquid crystal compound, or can be composed of two layers (not shown) in which the aforementioned cured layer and an orientation film are stacked. When the polarizing plate (1) is a single layer, the polarizing plate (10) has a stacked structure of the first resin layer (2) / the aforementioned cured layer / the second resin layer (3). When the polarizing plate (1) is composed of the above two layers, the polarizing plate (10) has a stacked structure of the first resin layer (2) / the aforementioned cured layer / the orientation film / the second resin layer (3). From the perspective of transmittance or polarization degree, the polarizer (1) is preferably composed of two layers in which the aforementioned cured product layer and the oriented film are stacked, and the polarizing plate (10) preferably has a stacked structure of a first resin layer (2) / the aforementioned cured product layer / the oriented film / the second resin layer (3). If necessary, the polarizing plate may have an adhesive layer (not shown) on the side of the first resin layer or the second resin layer opposite to the side adjacent to the polarizer. However, from the perspective of improving the heat resistance of the polarizing plate, it is preferably not provided with an adhesive layer. The adhesive layer has the function of bonding the polarizing plate to other components such as the front panel.

[0046] Hereinafter, each component of the polarizing plate according to one embodiment of the present invention will be described in detail.

[0047] <First resin layer>

[0048] The first resin layer is a cured product layer of a curable resin composition (hereinafter also referred to as the "first resin layer-forming composition") containing one or more monofunctional (meth)acrylates, one or more polyfunctional (meth)acrylates, and one or more urethane acrylates. It is laminated on one side of the polarizer. The cured product layer (cured film) of the first resin layer-forming composition is obtained by applying the first resin layer-forming composition to obtain a coating film, and then polymerizing the polymerizable compound contained in the coating film. In other words, the cured product layer of the first resin layer-forming composition is a layer formed by polymerizing the polymerizable compound. The first resin layer can help significantly inhibit or reduce the diffusion of components contained in the polarizer (such as dichroic compounds) into the first resin layer. It can also help prevent the polarizer from shrinking and expanding, and prevent degradation of the polarizer caused by temperature, humidity, ultraviolet light, etc. By including the first resin layer in the polarizer, the polarizing plate according to one embodiment of the present invention exhibits excellent durability and stable polarization performance even in high-temperature or high-humidity environments.

[0049] In addition, in this specification, (meth)acrylate means acrylate or methacrylate, and (meth)acryloyl means acryloyl or methacryloyl.

[0050] In the present invention, the cured product layer of the first resin layer-forming composition, i.e., the first resin layer, is obtained by curing (polymerizing) a coating film obtained by coating the first resin layer-forming composition on a polarizer or a resin film or surface-treated layer described below. The cured product layer of the first resin layer-forming composition comprises a polymer comprising a structural unit derived from a monofunctional (meth)acrylate, a structural unit derived from a polyfunctional (meth)acrylate, and a structural unit derived from a urethane acrylate. In one embodiment of the present invention described below, when the first resin layer-forming composition comprises a specific monofunctional (meth)acrylate, a specific polyfunctional (meth)acrylate, and a specific urethane acrylate, the cured product layer of the first resin layer-forming composition comprises a polymer comprising a structural unit derived from the specific monofunctional (meth)acrylate, a specific polyfunctional (meth)acrylate, and a specific urethane acrylate.

[0051] In one embodiment of the present invention, the coating film obtained by applying the first resin layer-forming composition does not need to be dried. If the polarizer contains a compound exhibiting dichroism, the heating step may cause its orientation disorder. When the first resin layer-forming composition is applied to the polarizer, if the first resin layer is obtained by polymerizing without drying (heating) (i.e., the solvent content in the first resin layer-forming composition is within the range described below), the possibility of causing the above-mentioned orientation disorder can be eliminated, thereby eliminating the possibility of reduced polarization performance of the resulting polarizing plate due to the above-mentioned disorder.

[0052] The mass ratio of the multifunctional (meth)acrylate to the monofunctional (meth)acrylate in the first resin layer-forming composition [mass of the multifunctional (meth)acrylate / mass of the monofunctional (meth)acrylate] is 1 or more. If the mass ratio is less than 1, the polarizing plate may not exhibit excellent durability under high temperature or high temperature and high humidity conditions. The mass ratio is preferably 1.1 or more, more preferably 1.2 or more, further preferably 1.4 or more, particularly preferably 1.6 or more, preferably 2.6 or less, more preferably 2.4 or less, further preferably 2.2 or less, and particularly preferably 2 or less. If the mass ratio is above the lower limit and below the upper limit, the polarizing plate can exhibit better durability even under high temperature or high temperature and high humidity conditions, and in particular, can achieve both better adhesion and transmittance.

[0053] The content of one or more monofunctional (meth)acrylates contained in the first resin layer-forming composition is preferably 20 parts by mass or more, more preferably 23 parts by mass or more, further preferably 25 parts by mass or more, and particularly preferably 28 parts by mass or more, and is preferably 50 parts by mass or less, more preferably 45 parts by mass or less, further preferably 40 parts by mass or less, and particularly preferably 35 parts by mass or less, relative to 100 parts by mass of the total of the monofunctional (meth)acrylate, polyfunctional (meth)acrylate, and urethane acrylate contained in the first resin layer-forming composition. If the above content is above the above lower limit, there is a tendency for the coating properties of the first resin layer-forming composition and the adhesion of the first resin layer to the polarizer to be excellent. If the above content is below the above upper limit, there is a tendency for the diffusion of components contained in the polarizer into the first resin layer to be more highly suppressed or reduced.

[0054] In the present invention, the content of structural units derived from one or more monofunctional (meth)acrylates in the first resin layer is preferably 20% by mass or more, more preferably 23% by mass or more, even more preferably 25% by mass or more, and particularly preferably 28% by mass or more, and is preferably 50% by mass or less, more preferably 45% by mass or less, even more preferably 40% by mass or less, and particularly preferably 35% by mass or less, relative to the mass of the polymer constituting the first resin layer. If the content is above the lower limit, the first resin layer tends to have excellent adhesion to the polarizer. If the content is below the upper limit, the diffusion of components contained in the polarizer into the first resin layer tends to be more highly suppressed or reduced.

[0055] The molecular weight of the monofunctional (meth)acrylate is preferably 300 or less, more preferably 250 or less, and even more preferably 210 or less. If the molecular weight of the monofunctional (meth)acrylate is below the aforementioned upper limit, the fluidity of the first resin layer-forming composition can be improved, thereby enabling the first resin layer-forming composition to be applied more uniformly and thinly to the polarizer, the resin film, or the surface-treated layer described later, resulting in a first resin layer with a more uniform and thinner thickness. The lower limit of the molecular weight of the monofunctional (meth)acrylate is generally 80 or greater. It should be noted that when the first resin layer-forming composition contains two or more monofunctional (meth)acrylates, it is preferable that the molecular weights of all types of monofunctional (meth)acrylates contained in the first resin layer-forming composition fall within the aforementioned range.

[0056] The aforementioned monofunctional (meth)acrylate is a compound having a monofunctional (meth)acryloyl group. Examples of such compounds include: (meth)acrylic acid; (meth)acrylic acid alkyl esters having 1 to 16 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, and tert-butyl (meth)acrylate; (meth)acrylic acid alkyl esters having 4 to 6 carbon atoms, such as cyclohexyl (meth)acrylate, 2-methylcyclohexyl (meth)acrylate, tricyclo[5.2.1.02,6]dec-8-yl (meth)acrylate, dicyclopentyloxyethyl (meth)acrylate, and isobornyl (meth)acrylate. cycloalkyl esters having 2 to 16 carbon atoms; β-carboxyalkyl (meth)acrylates having 2 to 14 carbon atoms; alkylated phenyl (meth)acrylates having 2 to 14 carbon atoms; methoxypolyethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate; (di)alkyl (meth)acrylamide having 4 to 16 carbon atoms; β-carboxyalkyl (meth)acrylamide having 2 to 14 carbon atoms; alkylated phenyl (meth)acrylamide having 2 to 14 carbon atoms; methoxypolyethylene glycol (meth)acrylamide; phenoxypolyethylene glycol (meth)acrylamide, etc.

[0057] The monofunctional (meth)acrylates can be used alone or in combination of two or more.

[0058] In a preferred embodiment, from the perspective of more effectively suppressing or reducing the diffusion of components contained in the polarizer into the first resin layer and more effectively preventing degradation of the polarizing plate, the monofunctional (meth)acrylate contained in the first resin layer-forming composition preferably includes a monofunctional (meth)acrylate having a hydroxyl group, and more preferably includes a monofunctional (meth)acrylate having a hydroxyl group at a terminal. In this embodiment, the monofunctional (meth)acrylate contained in the first resin layer-forming composition may include a monofunctional (meth)acrylate having a hydroxyl group at a terminal, a monofunctional (meth)acrylate having a hydroxyl group at a terminal and a monofunctional (meth)acrylate having a hydroxyl group other than a terminal, or a monofunctional (meth)acrylate having a hydroxyl group other than a terminal.

[0059] In one embodiment of the present invention, the content of the monofunctional (meth)acrylate having a hydroxyl group is preferably 20 parts by mass or more, more preferably 23 parts by mass or more, even more preferably 25 parts by mass or more, and particularly preferably 28 parts by mass or more, and preferably 50 parts by mass or less, more preferably 45 parts by mass or less, even more preferably 40 parts by mass or less, and particularly preferably 35 parts by mass or less, relative to 100 parts by mass of the total of the monofunctional (meth)acrylate, polyfunctional (meth)acrylate, and urethane acrylate contained in the first resin layer-forming composition. If the content of the monofunctional (meth)acrylate having a hydroxyl group in the first resin layer-forming composition is at least the lower limit, the dissolution-inhibiting effect of the hydroxyl group can suppress the deterioration of the polarization performance of the first resin layer over time. If the content of the monofunctional (meth)acrylate having a hydroxyl group in the first resin layer-forming composition is at most the upper limit, hydrogen bonding due to the hydroxyl group can be reduced, thereby lowering the viscosity of the first resin layer-forming composition.

[0060] The monofunctional (meth)acrylate having a hydroxyl group is preferably a monofunctional (meth)acrylate having a hydroxyl group at a terminal, and more preferably a compound represented by the following formula (1).

[0061] [Chemical Formula 2]

[0062]

[0063] [wherein, n represents an integer from 1 to 12,

[0064] A 1 represents O or NH,

[0065] X 1represents a methylene group which may have a substituent, and when n is an integer greater than 2, at least one of the methylene groups may be replaced by an oxygen atom, and the substituents may be the same or different.]

[0066] If the monofunctional (meth)acrylate having a hydroxyl group is a compound represented by the above formula (1), it is possible to more effectively suppress or reduce the diffusion of components contained in the polarizer into the first resin layer and more effectively prevent degradation of the polarizing plate. This is presumably because the terminal hydroxyl groups of the polymer of the monofunctional (meth)acrylate having a hydroxyl group in the first resin layer are more effectively inhibited from dissolving when the components contained in the polarizer dissolve and diffuse into the first resin layer.

[0067] In the above formula (1), n ​​is generally an integer of 1 to 12, preferably an integer of 2 to 10, more preferably an integer of 3 to 8, and even more preferably an integer of 4 to 6. If n is equal to or greater than the aforementioned lower limit, the hydroxyl group at the molecular terminal is less susceptible to the influence of the polymer main chain, and there is a tendency for the dissolution inhibitory effect of the hydroxyl group to be more effectively exerted. On the other hand, if n is equal to or less than the aforementioned upper limit, then X 1 When n is within the above range, the dissolution-inhibiting effect of the terminal hydroxyl groups of the polymer of the monofunctional (meth)acrylate having a hydroxyl group in the first resin layer tends to be more effectively exerted when the components contained in the polarizer dissolve and diffuse into the first resin layer.

[0068] In the above formula (1), A 1 Typically, it represents O or NH, preferably it represents O.

[0069] In the above formula (1), X 1 represents a methylene group which may have a substituent. When n is an integer greater than 2, at least one of the methylene groups may be replaced by an oxygen atom, and the substituents may be the same or different. Examples of the substituent include aliphatic or alicyclic hydrocarbon groups having 2 to 10 carbon atoms (e.g., 2 to 5 carbon atoms), or aromatic hydrocarbon groups having 5 to 20 carbon atoms (e.g., 5 to 11 carbon atoms). X, which is a methylene group in which at least one oxygen atom is replaced, 1 , for example: -(CH2CH2O) m -CH2CH2-, -(CH2CH(CH3)O) m -CH2CH(CH3)-[wherein, m represents an integer of 1 to 3], etc.

[0070] In one embodiment of the present invention, the content of the compound represented by formula (1) is preferably 20 parts by mass or more, more preferably 23 parts by mass or more, further preferably 25 parts by mass or more, and particularly preferably 28 parts by mass or more, and preferably 50 parts by mass or less, more preferably 45 parts by mass or less, further preferably 40 parts by mass or less, and particularly preferably 35 parts by mass or less, relative to 100 parts by mass of the total of the monofunctional (meth)acrylate, polyfunctional (meth)acrylate, and urethane acrylate contained in the first resin layer-forming composition. If the content of the compound represented by formula (1) in the first resin layer-forming composition is at least the lower limit, the deterioration of the polarization performance of the first resin layer over time can be suppressed due to the dissolution inhibitory effect of the hydroxyl group. In addition, the fluidity of the first resin layer-forming composition is particularly good, and thus the deterioration of the polarization performance of the polarizer associated with the drying process can be further suppressed. If the content of the compound represented by formula (1) in the first resin layer-forming composition is at most the upper limit, the formation of hydrogen bonds due to the hydroxyl group can be reduced, and the viscosity of the first resin layer-forming composition can be reduced.

[0071] Examples of monofunctional (meth)acrylates having a hydroxyl group include hydroxyalkyl (meth)acrylates having 4 to 16 carbon atoms, hydroxycycloalkyl (meth)acrylates having 4 to 16 carbon atoms, hydroxyalkylated phenyl (meth)acrylates having 2 to 14 carbon atoms, polyethylene glycol (meth)acrylates, hydroxy(di)alkyl (meth)acrylamides having 4 to 16 carbon atoms, hydroxyalkylated phenyl (meth)acrylamides having 2 to 14 carbon atoms, and polyethylene glycol (meth)acrylamides. Preferred examples include hydroxyalkyl (meth)acrylates having 4 to 6 carbon atoms and hydroxycycloalkyl (meth)acrylates having 4 to 16 carbon atoms, and more preferred examples include hydroxyalkyl acrylates having 4 to 6 carbon atoms and hydroxycycloalkyl acrylates having 4 to 16 carbon atoms.

[0072] The monofunctional (meth)acrylate having a hydroxyl group can be used alone or in combination of two or more.

[0073] The composition for forming the first resin layer further contains one or more multifunctional (meth)acrylates, i.e., one or more difunctional or higher-functional (meth)acrylates. The multifunctional (meth)acrylate contained in the composition for forming the first resin layer preferably contains a multifunctional (meth)acrylate that is preferably trifunctional or higher, more preferably tetrafunctional or higher, and even more preferably pentafunctional or higher. If the multifunctional (meth)acrylate has the above-mentioned number of functional groups, the crosslinking density of the polymerizable compound contained in the first resin layer is increased, which not only can more highly inhibit or reduce the diffusion of components contained in the polarizer into the first resin layer, but also can reduce dependence on the external environment to which the polarizing plate is exposed. The number of functional groups of the multifunctional (meth)acrylate is generally 20 or less, more preferably 10 or less, and even more preferably 8 or less. It should be noted that when the first resin layer-forming composition contains two or more polyfunctional (meth)acrylates, it is preferred that the number of functional groups of all types of polyfunctional (meth)acrylates contained in the first resin layer-forming composition be greater than or equal to the aforementioned lower limit and less than or equal to the aforementioned upper limit, and the number of functional groups may be the same or different between the individual polyfunctional (meth)acrylates.

[0074] Examples of the bifunctional (meth)acrylate include alkylene glycol di(meth)acrylates such as ethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, and neopentyl glycol di(meth)acrylate; and diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, and polyoxyethylene glycol di(meth)acrylate. Polyoxyalkylene glycol di(meth)acrylates such as ethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, and polytetramethylene glycol di(meth)acrylate; di(meth)acrylates of halogen-substituted alkylene glycols such as tetrafluoroethylene glycol di(meth)acrylate; di(meth)acrylates of aliphatic polyols such as trimethylolpropane di(meth)acrylate, ditrimethylolpropane di(meth)acrylate, and pentaerythritol di(meth)acrylate; hydrogenated dicyclopentadienyl di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, and the like. Di(meth)acrylates of hydrogenated dicyclopentadiene or tricyclodecanediol such as bisphenol-1,3-dioxane-2,5-diyl di(meth)acrylate; di(meth)acrylates of dioxanediol or dioxanediol such as 1,3-dioxane-2,5-diyl di(meth)acrylate [Other name: dioxanediol di(meth)acrylate]; di(meth)acrylates of alkylene oxide adducts of bisphenol A or bisphenol F such as bisphenol A ethylene oxide adduct diacrylate and bisphenol F ethylene oxide adduct diacrylate; acrylic acid adducts of bisphenol A diglycidyl ether and acrylic acid adducts of bisphenol F diglycidyl ether Epoxy di(meth)acrylate of bisphenol A or bisphenol F; silicone di(meth)acrylate; di(meth)acrylate of hydroxypivalate neopentyl glycol; 2,2-bis[4-(meth)acryloyloxyethoxyethoxyphenyl]propane; 2,2-bis[4-(meth)acryloyloxyethoxyethoxycyclohexyl]propane; di(meth)acrylate of 2-(2-hydroxy-1,1-dimethylethyl)-5-ethyl-5-hydroxymethyl-1,3-dioxane]; tris(hydroxyethyl)isocyanurate di(meth)acrylate, etc.

[0075] Examples of the trifunctional (meth)acrylate include glycerol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and a reaction product of pentaerythritol tri(meth)acrylate and an acid anhydride; caprolactone-modified trimethylolpropane tri(meth)acrylate, caprolactone-modified pentaerythritol tri(meth)acrylate, and ethylene oxide-modified trimethylolpropane tri(meth)acrylate. Ester, ethylene oxide modified pentaerythritol tri(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate, propylene oxide modified pentaerythritol tri(meth)acrylate, isocyanurate tri(meth)acrylate, the reaction product of caprolactone modified pentaerythritol tri(meth)acrylate and acid anhydride; the reaction product of ethylene oxide modified pentaerythritol tri(meth)acrylate and acid anhydride; the reaction product of propylene oxide modified pentaerythritol tri(meth)acrylate and acid anhydride, etc.

[0076] Examples of the tetrafunctional (meth)acrylate include ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, tripentaerythritol tetra(meth)acrylate, caprolactone-modified pentaerythritol tetra(meth)acrylate, caprolactone-modified tripentaerythritol tetra(meth)acrylate, ethylene oxide-modified pentaerythritol tetra(meth)acrylate, ethylene oxide-modified tripentaerythritol tetra(meth)acrylate, propylene oxide-modified pentaerythritol tetra(meth)acrylate, and propylene oxide-modified tripentaerythritol tetra(meth)acrylate.

[0077] Examples of the pentafunctional (meth)acrylate include dipentaerythritol penta(meth)acrylate, tripentaerythritol penta(meth)acrylate, and a reaction product of dipentaerythritol penta(meth)acrylate and an acid anhydride; caprolactone-modified dipentaerythritol penta(meth)acrylate, caprolactone-modified tripentaerythritol penta(meth)acrylate, ethylene oxide-modified dipentaerythritol penta(meth)acrylate, ethylene oxide-modified tripentaerythritol penta(meth)acrylate, propylene oxide-modified dipentaerythritol penta(meth)acrylate, propylene oxide-modified tripentaerythritol penta(meth)acrylate, and a reaction product of caprolactone-modified dipentaerythritol penta(meth)acrylate and an acid anhydride; a reaction product of ethylene oxide-modified dipentaerythritol penta(meth)acrylate and an acid anhydride; and a reaction product of propylene oxide-modified dipentaerythritol penta(meth)acrylate and an acid anhydride.

[0078] Examples of the hexafunctional (meth)acrylate include dipentaerythritol hexa(meth)acrylate, tripentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, caprolactone-modified tripentaerythritol hexa(meth)acrylate, ethylene oxide-modified dipentaerythritol hexa(meth)acrylate, ethylene oxide-modified tripentaerythritol hexa(meth)acrylate, propylene oxide-modified dipentaerythritol hexa(meth)acrylate, and propylene oxide-modified tripentaerythritol hexa(meth)acrylate.

[0079] Examples of the heptafunctional (meth)acrylate include tripentaerythritol hepta(meth)acrylate and a reaction product of tripentaerythritol hepta(meth)acrylate and an acid anhydride; caprolactone-modified tripentaerythritol hepta(meth)acrylate and a reaction product of caprolactone-modified tripentaerythritol hepta(meth)acrylate and an acid anhydride; ethylene oxide-modified tripentaerythritol hepta(meth)acrylate and a reaction product of ethylene oxide-modified tripentaerythritol hepta(meth)acrylate and an acid anhydride; and propylene oxide-modified tripentaerythritol hepta(meth)acrylate and a reaction product of propylene oxide-modified tripentaerythritol hepta(meth)acrylate and an acid anhydride.

[0080] Examples of the octafunctional (meth)acrylate include tripentaerythritol octa(meth)acrylate, caprolactone-modified tripentaerythritol octa(meth)acrylate, ethylene oxide-modified tripentaerythritol octa(meth)acrylate, and propylene oxide-modified tripentaerythritol octa(meth)acrylate.

[0081] These polyfunctional (meth)acrylates can be used alone or in combination of two or more.

[0082] Multifunctional (meth)acrylates can adjust the crosslink density of the first resin layer based on their molecular weight between crosslinks and the number of crosslinks. More specifically, a lower molecular weight between crosslinks in the multifunctional (meth)acrylate increases the crosslink density of the first resin layer. Conversely, a higher number of crosslinks in the multifunctional (meth)acrylate results in a more uniform crosslink density in the first resin layer. As a result, diffusion of polarizing plate components into the first resin layer can be significantly suppressed or reduced, reducing dependence on the external environment to which the polarizing plate is exposed.

[0083] In one embodiment of the present invention, to increase crosslink density, the multifunctional (meth)acrylate has a branched structure. The number of atoms in the chain linking the branch point closest to the (meth)acryloyl group and the (meth)acryloyl group (hereinafter sometimes referred to as a "linking chain") is preferably 3 or less, and more preferably 2 or less. If this number of atoms is below the aforementioned upper limit, the crosslink density of the first resin layer increases, which can further suppress or reduce the diffusion of components contained in the polarizer into the first resin layer, and reduce dependence on the external environment to which the polarizing plate is exposed. In the case of multiple linking chains, it is sufficient for at least one linking chain to fall within the aforementioned range of atoms. To increase crosslink density, it is preferable for all linking chains to fall within the aforementioned range of atoms.

[0084] Among the polyfunctional (meth)acrylates, dipentaerythritol hexa(meth)acrylate and tripentaerythritol octa(meth)acrylate are preferred from the viewpoint of increasing the crosslinking density of the polarizing film.

[0085] Alternatively, commercially available multifunctional (meth)acrylates may be used. Examples of such commercially available products include A-DOD-N, A-HD-N, A-NOD-N, APG-100, APG-200, APG-400, A-GLY-9E, A-GLY-20E, A-TMM-3, A-TMPT, AD-TMP, ATM-35E, A-TMMT, A-9550, A-DPH, HD-N, NOD-N, NPG, and TMPT (all manufactured by Shin-Nakamura Chemical Co., Ltd.); ARONIX M-220, ARONIX M-325, ARONIX M-240, ARONIX M-270, ARONIX M-309, ARONIX M-310, ARONIX M-321, ARONIX M-350, ARONIX M-360, ARONIX M-305, ARONIX M-306, and ARONIX M-450, ARONIX M-451, ARONIX M-408, ARONIX M-400, ARONIX M-402, ARONIX M-403, ARONIX M-404, ARONIX M-405, ARONIX M-406 (all manufactured by Toagosei Co., Ltd.); EBECRYL 11, EBECRYL 145, EBECRYL 150, EBECRYL 40, EBECRYL 140, EBECRYL 180, DPGDA, HDDA, TPGDA, HPNDA, PETIA, PETRA, TMPTA, TMPEOTA, DPHA, EBECRYL series (all manufactured by Daicel-Cytec Co., Ltd.), Light Acrylate PE-3A (manufactured by Kyoeisha Chemical Co., Ltd.), etc.

[0086] The content of the polyfunctional (meth)acrylate contained in the composition for forming the first resin layer is preferably 40 parts by mass or more, more preferably 45 parts by mass or more, further preferably 50 parts by mass or more, and particularly preferably 55 parts by mass or more, relative to 100 parts by mass of the total of the monofunctional (meth)acrylate, polyfunctional (meth)acrylate, and urethane acrylate contained in the composition for forming the first resin layer, and is preferably 75 parts by mass or less, more preferably 70 parts by mass or less, further preferably 65 parts by mass or less, and particularly preferably 60 parts by mass or less. If the content of the polyfunctional (meth)acrylate contained in the composition for forming the first resin layer is above the aforementioned lower limit, not only can the diffusion of components contained in the polarizer into the first resin layer be more highly suppressed or reduced, but also the dependence on the external environment to which the polarizer is exposed can be reduced. If the content of the polyfunctional (meth)acrylate contained in the composition for forming the first resin layer is below the aforementioned upper limit, curling and brittleness of the first resin layer can be suppressed.

[0087] The first resin layer-forming composition contains a difunctional or higher-functional, particularly trifunctional or higher-functional (more particularly pentafunctional or higher-functional), polymerizable compound. This results in the suppression of the migration of components contained in the polarizer into the first resin layer. On the other hand, because difunctional or higher-functional, particularly trifunctional or higher-functional (more particularly pentafunctional or higher-functional) polymerizable compounds have a bulky structure, a solvent is typically added to the first resin layer-forming composition to improve fluidity in order to obtain a uniform and thin first resin layer. However, this added solvent may cause the migration of components contained in the polarizer into the first resin layer. In the present invention, by using a specific first resin layer-forming composition, the first resin layer-forming composition maintains sufficient fluidity even when a small amount of solvent is added or no solvent is added. This allows for the production of a uniform and thin first resin layer, while also suppressing the migration of components contained in the polarizer into the first resin layer.

[0088] In the present invention, the content of the structural units derived from the multifunctional (meth)acrylate in the first resin layer is preferably 40% by mass or more, more preferably 45% by mass or more, further preferably 50% by mass or more, particularly preferably 55% by mass or more, and preferably 75% by mass or less, more preferably 70% by mass or less, further preferably 65% ​​by mass or less, and particularly preferably 60% by mass or less, relative to the mass of the polymer constituting the first resin layer. If the above content is above the above lower limit, not only can the diffusion of components contained in the polarizer into the first resin layer be more highly suppressed or reduced, but the dependence on the external environment to which the polarizing plate is exposed can also be reduced. If the content of the multifunctional (meth)acrylate contained in the composition for forming the first resin layer is below the above upper limit, curling and brittleness of the first resin layer can be suppressed.

[0089] The first resin layer forming composition also contains one or more urethane acrylates. Urethane acrylates generally refer to reactants of isocyanate compounds, polyol compounds, and acrylate compounds. The number of functional groups of the urethane acrylate, that is, the number of acryloyloxy groups contained in the molecule, is 3 or more, preferably 4 or more, more preferably 5 or more, and even more preferably 6 or more. If the urethane acrylate has functional groups above the above value, the crosslinking density of the polymer of the polymerizable compound contained in the first resin layer is increased, which can not only more highly suppress or reduce the diffusion of the components contained in the polarizer to the first resin layer, but also reduce the dependence on the external environment to which the polarizing plate is exposed. In addition, since appropriate toughness can be imparted to the first resin layer, it can contribute to improving the bendability of the polarizing plate and improving the tolerance to deformation caused by bending, etc. The number of functional groups of the urethane acrylate is generally 10 or less, and from the perspective of the coatability of the first resin layer forming composition, it is preferably 8 or less. It should be noted that when the first resin layer-forming composition contains two or more urethane acrylates, it is preferred that the number of functional groups of all types of urethane acrylates contained in the first resin layer-forming composition be greater than or equal to the aforementioned lower limit and less than or equal to the aforementioned upper limit, and the number of functional groups may be the same or different between the individual urethane acrylates.

[0090] The weight-average molecular weight (Mw) of the urethane acrylate, calculated on a polystyrene basis, is preferably 300 or greater, more preferably 400 or greater, and is preferably 10,000 or less, more preferably 7,000 or less, even more preferably 5,000 or less, and particularly preferably 3,000 or less. When the Mw of the urethane acrylate is within the aforementioned range, the adhesion and heat resistance of the first resin layer to adjacent layers can be further improved. The weight-average molecular weight can be measured, for example, by gel permeation chromatography (GPC).

[0091] The number of acryloyloxy groups per unit molecular weight of the urethane acrylate is preferably 15×10 -4 More than 20×10 -4 More than 30×10 -4 Above, particularly preferably 40×10 -4 If the number of acryloyloxy groups per unit molecular weight is greater than the aforementioned lower limit, the adhesion and heat resistance of the first resin layer to adjacent layers can be further improved. Furthermore, the upper limit of the number of acryloyloxy groups per unit molecular weight is generally 20 or less. The number of acryloyloxy groups per unit molecular weight can be calculated using the following formula: number of acryloyloxy groups in urethane acrylate / weight average molecular weight (Mw).

[0092] The content of the urethane acrylate contained in the composition for forming the first resin layer is preferably 5 parts by mass or more, more preferably 8 parts by mass or more, further preferably 10 parts by mass or more, particularly preferably 12 parts by mass or more, and preferably 40 parts by mass or less, more preferably 33 parts by mass or less, further preferably 25 parts by mass or less, and particularly preferably 20 parts by mass or less, relative to 100 parts by mass of the total of the monofunctional (meth)acrylate, multifunctional (meth)acrylate, and urethane acrylate contained in the composition for forming the first resin layer. If the content of the urethane acrylate contained in the composition for forming the first resin layer is greater than the aforementioned lower limit, the diffusion of components contained in the polarizer into the first resin layer can be more highly suppressed or reduced, and the dependence on the external environment to which the polarizing plate is exposed can be reduced. If the content of the urethane acrylate contained in the composition for forming the first resin layer is less than the aforementioned upper limit, the coating properties of the composition for forming the first resin layer can be improved, and curling and brittleness of the first resin layer can be suppressed.

[0093] The mass ratio of the monofunctional (meth)acrylate to the urethane acrylate in the first resin layer-forming composition [mass of monofunctional (meth)acrylate / mass of urethane acrylate] is preferably 0.5 or greater, more preferably 1 or greater, even more preferably 1.5 or greater, and particularly preferably 1.8 or greater, and is preferably 10 or less, more preferably 7.5 or less, more preferably 6 or less, even more preferably 5 or less, even more preferably 3.5 or less, and particularly preferably 2.8 or less. When the mass ratio is above the lower limit and below the upper limit, the polarizing plate can exhibit superior durability even in high-temperature environments or high-temperature and high-humidity environments, and in particular, can achieve both superior adhesion and transmittance.

[0094] The mass ratio of the polyfunctional (meth)acrylate to the urethane acrylate in the first resin layer-forming composition [mass of polyfunctional (meth)acrylate / mass of urethane acrylate] is preferably 0.5 or greater, more preferably 1.2 or greater, even more preferably 2.1 or greater, and particularly preferably 2.9 or greater, and is preferably 26 or less, more preferably 12 or less, even more preferably 7.7 or less, and particularly preferably 5.6 or less. When the mass ratio is above the lower limit and below the upper limit, the polarizing plate can exhibit superior durability even in high-temperature environments or high-temperature and high-humidity environments, and in particular, can achieve both superior adhesion and transmittance.

[0095] The first resin layer forming composition may contain a solvent. The content of the solvent in the first resin layer forming composition is preferably 5% by mass or less relative to the total mass of the first resin layer forming composition, more preferably 3% by mass or less, further preferably 1% by mass or less, and particularly preferably 0% by mass. If the content of the solvent in the first resin layer forming composition is below the above-mentioned upper limit, even if the drying process is not performed when making the polarizing plate of one embodiment of the present invention, the content of the solvent in the first resin layer can be suppressed to a low level, thereby not causing the polarization performance of the polarizing plate to decrease due to the drying process, and the polarization performance of the polarizing plate can be suppressed over time. It should be noted that the content of the solvent in the first resin layer forming composition is particularly preferably 0% by mass (preferably 5% by mass or less), but since the first resin layer forming composition in the present invention has good fluidity, even if the first resin layer forming composition does not contain a solvent (or contains only a small amount of solvent), a uniform and thin coating film can be obtained. The lower limit of the content of the solvent in the first resin layer forming composition is 0% by mass or more relative to the total mass of the first resin layer forming composition.

[0096] Examples of usable solvents include any solvent capable of dissolving the components of the first resin layer-forming composition, such as aliphatic hydrocarbons such as hexane and octane; aromatic hydrocarbons such as toluene and xylene; alcohols such as ethanol, 1-propanol, isopropanol, and 1-butanol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate, butyl acetate, and isobutyl acetate; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether; and esterified glycol ethers such as ethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate. These solvents may be used alone or in combination of two or more.

[0097] The first resin layer-forming composition may optionally contain one or more additives commonly used in curable compositions. Examples of such additives include polymerization initiators, sensitizers, polymerization inhibitors, leveling agents, reactive additives, ion traps, antioxidants, chain transfer agents, polymerization accelerators (such as polyols), sensitizers, light stabilizers, tackifiers, thermoplastic resins, fillers, flow regulators, plasticizers, defoamers, silane coupling agents, pigments, antistatic agents, and UV absorbers.

[0098] The first resin layer-forming composition may contain a polymerization initiator. A polymerization initiator is a compound that can initiate a polymerization reaction of a monofunctional (meth)acrylate, a polyfunctional (meth)acrylate, or a urethane acrylate. Preferred polymerization initiators are photopolymerization initiators that generate active radicals under the action of light.

[0099] Examples of the polymerization initiator include benzoin compounds, benzophenone compounds, alkylphenone compounds, acylphosphine oxide compounds, triazine compounds, iodonium salts, and sulfonium salts. The polymerization initiator may be used alone or in combination of two or more.

[0100] Examples of the benzoin compound include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether.

[0101] Examples of the benzophenone compound include benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4′-methyldiphenyl sulfide, 3,3′,4,4′-tetrakis(tert-butylperoxycarbonyl)benzophenone, and 2,4,6-trimethylbenzophenone.

[0102] Examples of the alkylphenone compound include diethoxyacetophenone, 2-methyl-2-morpholino-1-(4-methylthiophenyl)propane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butane-1-one, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1,2-diphenyl-2,2-dimethoxyethane-1-one, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]propane-1-one, 1-hydroxycyclohexylphenyl ketone, and oligomers of 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propane-1-one.

[0103] Examples of the acylphosphine oxide compound include 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0104] Examples of the triazine compound include 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxynaphthyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine, and 2,4-bis(trichloromethyl)-6-[2-(5-methylfuran-2-yl)]-1,3,5-triazine. vinyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(furan-2-yl)vinyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(4-diethylamino-2-methylphenyl)vinyl]-1,3,5-triazine and 2,4-bis(trichloromethyl)-6-[2-(3,4-dimethoxyphenyl)vinyl]-1,3,5-triazine, etc.

[0105] As the polymerization initiator, a commercially available polymerization initiator may also be used. Examples of commercially available polymerization initiators include: Irgacure (registered trademark) 907, Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, and Irgacure 369 (manufactured by Ciba Specialty Chemicals Co., Ltd.); Omnirad 819, Omnirad 907, Esacure 1001M, and Esacure KIP160 (manufactured by IDM Resins BV); SEIKUOL (registered trademark) BZ, SEIKUOL Z, and SEIKUOL BEE (manufactured by Seiko Chemical Co., Ltd.); Kayacure (registered trademark) BP100 and Kayacure UVI-6992 (manufactured by Dow Chemical Co., Ltd.); Adeka Optomer SP-152 and Adeka Optomer SP-170 (manufactured by ADEKA Co., Ltd.); TAZ-A and TAZ-PP (manufactured by SiberHegner Co., Ltd. of Japan); TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.), etc.

[0106] When the first resin layer-forming composition contains a polymerization initiator, its content can be appropriately selected depending on the type and amount of the polymerizable compound. From the perspective of initiator efficiency, the content is generally 0.1 to 40 parts by mass, preferably 0.2 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 1 to 5 parts by mass, relative to 100 parts by mass of the total mass of the polymerizable compound contained in the first resin layer-forming composition.

[0107] When the first resin layer-forming composition contains a leveling agent, from the viewpoint of smoothness of the resulting first resin layer, the content thereof is preferably 0 to 6 parts by mass, more preferably 0.01 to 5 parts by mass, even more preferably 0.05 to 5 parts by mass, and particularly preferably 0.08 to 3 parts by mass, relative to 100 parts by mass of the total mass of the polymerizable compound contained in the first resin layer-forming composition. The leveling agent may be used alone or in combination of two or more.

[0108] The viscosity of the composition for forming the first resin layer is preferably 350 cps or less at 25°C, more preferably 300 cps or less, further preferably 280 cps or less, and particularly preferably 250 cps or less. If the viscosity is below the upper limit, the fluidity of the composition for forming the first resin layer is better, so the composition for forming the first resin layer can be evenly and thinly coated on the polarizer or the resin film or surface treatment layer described later, and a first resin layer with a more uniform thickness and a thinner type can be obtained. The pumpability of the composition for forming the first resin layer is excellent in the manufacturing process of the polarizing plate. The lower limit of the viscosity of the composition for forming the first resin layer at 25°C is usually 5 cps or more. The viscosity can be measured in accordance with JIS K7367. In a preferred embodiment, the viscosity of the composition for forming the first resin layer when the content of the solvent in the composition for forming the first resin layer is within the above range is below the upper limit.

[0109] The solid content of the first resin layer forming composition is preferably 95% by mass or more relative to the mass of the first resin layer forming composition, more preferably 97% by mass or more, further preferably 99% by mass or more, and particularly preferably 100% by mass. If the solid content is above the lower limit, even if the drying process after applying the first resin layer forming composition is not performed, a first resin layer with a more uniform and thin thickness can be obtained, so the polarization performance of the polarizing plate caused by the drying process will not be reduced, and the polarization performance of the polarizing plate can be suppressed over time. It should be noted that in this specification, the so-called solid content refers to the total amount of the component after removing the solvent from the resin composition.

[0110] The thickness of the first resin layer is not particularly limited, but is generally 10 μm or less, preferably 0.15 to 5 μm, more preferably 0.5 to 4 μm, and even more preferably 1.0 to 3 μm.

[0111] One or more layers selected from a resin film and a surface-treated layer may be laminated on the side of the first resin layer opposite to the polarizer.

[0112] In one embodiment of the present invention, the polarizing plate includes a resin film on the side of the first resin layer opposite to the polarizer.

[0113] The purpose of the resin film is to improve the mechanical strength of the polarizing plate and prevent damage to the polarizing plate surface. From the viewpoint of improving the mechanical strength of the polarizing plate and preventing damage to the polarizing plate surface, the polarizing plate preferably includes a resin film adjacent to the side of the first resin layer opposite to the polarizer.

[0114] As the resin film, for example, a resin film obtained by forming the following resins into a film by a known method such as a solvent casting method and a melt extrusion method can be used: polyolefin resins such as polyethylene and polypropylene; cyclic olefin resins such as norbornene polymers; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; poly(meth)acrylic acid resins such as (meth)acrylic acid and polymethyl (meth)acrylate; cellulose ester resins such as cellulose triacetate, cellulose diacetate and cellulose acetate propionate; vinyl alcohol resins such as polyvinyl alcohol and polyvinyl acetate; polycarbonate resins; polystyrene resins; polyarylate resins; polysulfone resins; polyethersulfone resins; polyamide resins; polyimide resins; polyether ketone resins; polyphenylene sulfide resins; polyphenylene ether resins and mixtures of these resins can be used. Among the above resins, from the perspectives of versatility and heat resistance, at least one selected from polyimide resins, cellulose ester resins, cyclic olefin resins, polyester resins, and poly(meth)acrylic resins is preferred, with cellulose ester resins and cyclic olefin resins being more preferred. Commercially available cyclic olefin resins may also be used, and examples thereof include: "Topas" (registered trademark) (manufactured by Ticona GmbH (Germany)); "ARTON" (registered trademark) (manufactured by JSR Corporation); "ZEONOR" (registered trademark), "ZEONEX" (registered trademark) (all manufactured by ZEON Corporation of Japan); and "APEL" (registered trademark) (manufactured by Mitsui Chemicals, Inc.).

[0115] As the resin film, commercially available resin films can be used. Examples include cellulose ester resin films such as FUJITAC FILM (manufactured by Fujifilm Corporation), KC8UX2M, KC8UY, and KC4UY (all manufactured by Konica Minolta Opto Co., Ltd.); and cyclic olefin resin films such as Escena (registered trademark), SCA40 (registered trademark) (all manufactured by Sekisui Chemical Co., Ltd.), ZEONOR Film (registered trademark) (manufactured by ZEON Corporation), and ARTON Film (registered trademark) (manufactured by JSR Corporation).

[0116] Examples of the surface treatment layer include optical layers such as a hard coat layer, an antireflection layer, an anti-blocking layer, an antiglare layer, and a diffusion layer.

[0117] The purpose of the hard coat layer is to prevent damage to the polarizing plate surface. The hard coat layer can be formed, for example, by adding a cured layer having excellent hardness and sliding properties to the surface of the first resin layer, wherein the cured layer is a cured layer of a curable resin composition containing an ultraviolet curable resin such as an acrylic resin or a silicone resin.

[0118] The purpose of the antireflection layer is to prevent external light from being reflected on the surface of the polarizing plate, and the antireflection layer can be added to the surface of the first resin layer by forming an antireflection film according to a conventional method.

[0119] The purpose of the anti-blocking layer is to prevent adhesion to adjacent layers.

[0120] The purpose of the anti-glare layer is to prevent external light from being reflected from the polarizing plate surface, thereby obstructing the visibility of light transmitted through the polarizing plate. The anti-glare layer can be formed, for example, by imparting a fine concavo-convex structure to the surface of the first resin layer through roughening methods such as sandblasting or embossing, or by incorporating transparent fine particles. Examples of fine particles included in the anti-glare layer-forming composition to form this fine concavo-convex surface structure include inorganic fine particles with an average particle size of 0.5 to 50 μm, containing silica, alumina, titanium dioxide, zirconium oxide, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like, which may be conductive; and transparent fine particles such as organic fine particles containing crosslinked or uncrosslinked polymers. When fine particles are used to form the fine concavo-convex surface structure, the content of the fine particles is typically 2 to 50 parts by mass, preferably 5 to 25 parts by mass, per 100 parts by mass of the transparent resin contained in the anti-glare layer-forming composition. The anti-glare layer can also function as a diffusion layer (performing a viewing angle widening function, etc.) to diffuse light transmitted through the polarizing plate, thereby widening the viewing angle.

[0121] It should be noted that the above-mentioned resin film, hard coating layer, anti-reflection layer, anti-adhesion layer, anti-glare layer or diffusion layer can not only be set integrally with the first resin layer itself, but can also be set separately from the first resin layer as an optical layer and then stacked on the first resin layer.

[0122] Polarizing Plate

[0123] The polarizer in the present invention is a polarizing film containing a cured layer of a polymerizable liquid crystal composition containing a compound exhibiting dichroism and a polymerizable liquid crystal compound (preferably a non-coloring polymerizable liquid crystal compound). The polarizing film is composed of a single layer of a cured layer of a polymerizable liquid crystal composition containing a compound exhibiting dichroism and a polymerizable liquid crystal compound (hereinafter also referred to as a "polarizer-forming composition"), or is composed of two layers: a cured layer of the polarizer-forming composition and an adjacent alignment film. When the polarizing film is composed of a single cured layer of the polarizer-forming composition, the polarizing plate has a laminated structure of a first resin layer / cured layer of the polarizer-forming composition / an optional second resin layer. When the polarizing film is composed of two layers, the polarizing plate has a laminated structure of a first resin layer / cured layer of the polarizer-forming composition / alignment film / an optional second resin layer. From the perspective of improving mechanical strength, the polarizer is preferably composed of two layers in which the aforementioned cured layer and alignment film are laminated, and the polarizing plate preferably has a laminated structure of a first resin layer / the aforementioned cured layer / alignment film / an optional second resin layer. From the perspective of orientation, the cured layer of the polymerizable liquid crystal composition in the polarizer is a film in which the compound exhibiting dichroism is oriented in a film formed by a polymer of the polymerizable liquid crystal compound, preferably a film in which the polymerizable liquid crystal compound is cured in a state in which it is oriented in a horizontal direction relative to the bonding surface with the first resin layer.

[0124] From the perspective of the orientation of the polymerizable liquid crystal compound, the thickness of the cured layer of the polarizer-forming composition in the polarizer is preferably 0.5 μm to 5 μm, and more preferably 1 μm to 3.5 μm. If the thickness of the cured layer is above the lower limit, alignment in the vertical alignment direction is less likely to occur, and thus the orientation order (orientation order) tends to increase. If the thickness of the cured layer is below the upper limit, alignment in the random alignment direction is less likely to occur, and thus the orientation order tends to increase. The thickness of the cured layer can be measured, for example, using an interferometer, a laser microscope, or a stylus-type film thickness meter.

[0125] When the polarizer includes an alignment film, its thickness is preferably 10 to 5000 nm, more preferably 10 to 1000 nm, even more preferably 10 to 500 nm, and particularly preferably 10 to 300 nm, 10 to 200 nm, or 30 to 100 nm. When the alignment film thickness falls within the aforementioned ranges, good adhesion to the interface with the adjacent layer is achieved, and alignment-regulating forces (orientational regulation forces) are exerted, enabling the polarizer to be formed with a high degree of alignment order.

[0126] The method for manufacturing the polarizer is not particularly limited. For example, the polarizer can be manufactured by a method comprising the following steps: applying a polarizer-forming composition containing a compound exhibiting dichroism and a polymerizable liquid crystal compound to the surface of an alignment film, a first resin layer, a second resin layer, a resin film, or a surface-treated layer (preferably the surface of an alignment film) to form a coating film; and a step of polymerizing the aforementioned polymerizable liquid crystal compound. Here, the polymerizable liquid crystal compound is preferably polymerized in an oriented state, particularly in a state in which it is oriented in a horizontal direction relative to the bonding surface with the first resin layer. In addition, when the polarizer-forming composition contains a solvent, the step of drying the coating film as needed may be included. As drying methods, natural drying, ventilation drying, heating drying, and reduced pressure drying methods can be cited.

[0127] (Polymerizable liquid crystal compound)

[0128] A polymerizable liquid crystal compound is a compound having a polymerizable group and having liquid crystal properties. The polymerizable liquid crystal compound is preferably a colorless, i.e., non-coloring polymerizable liquid crystal compound. A polymerizable group refers to a group that participates in the polymerization reaction, preferably a photopolymerizable group. Here, a photopolymerizable group refers to a group that can participate in the polymerization reaction through active free radicals or acids generated by a photopolymerization initiator described later. Examples of polymerizable groups include: vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloyloxy, methacryloyloxy, oxiranyl, oxetane, etc. Among them, acryloyloxy, methacryloyloxy, vinyloxy, oxiranyl, and oxetane are preferred, and acryloyloxy is more preferred. The liquid crystal properties may be thermotropic or lyotropic.

[0129] The polymerizable liquid crystal compound may be a thermotropic liquid crystal compound exhibiting a nematic liquid crystal phase or a thermotropic liquid crystal compound exhibiting a smectic liquid crystal phase. In the present invention, the polymerizable liquid crystal compound is preferably a thermotropic liquid crystal compound exhibiting a smectic liquid crystal phase, and more preferably a thermotropic liquid crystal compound exhibiting a higher-order (higher order) smectic liquid crystal phase, from the perspective of excellent orientation and achieving higher polarization characteristics. Among these, thermotropic liquid crystal compounds exhibiting a smectic B phase, a smectic D phase, a smectic E phase, a smectic F phase, a smectic G phase, a smectic H phase, a smectic I phase, a smectic J phase, a smectic K phase, or a smectic L phase are more preferred, and thermotropic liquid crystal compounds exhibiting a smectic B phase, a smectic F phase, a smectic H phase, or a smectic I phase are even more preferred. If the liquid crystal phase formed by the polymerizable liquid crystal compound is one of these higher-order smectic liquid crystal phases, a polarizer with even higher polarization performance can be produced. Furthermore, such polarizers with high polarization performance preferably exhibit a Bragg peak in X-ray diffraction measurements. Such polarizers can exhibit Bragg peaks originating from high-order structures such as hexagonal phases or crystalline phases. These Bragg peaks are peaks derived from periodic structures of molecular orientation, and films with periodic spacings of 3 to 6 Å can be obtained. Furthermore, to achieve even higher polarization properties, in one embodiment of the polarizer of the present invention, the polymer of the polymerizable liquid crystal compound preferably exhibits a smectic liquid crystal phase, particularly a high-order smectic liquid crystal phase.

[0130] Specific examples of such polymerizable liquid crystal compounds include compounds represented by the following formula (A) (hereinafter sometimes referred to as compound (A)). These polymerizable liquid crystal compounds may be used alone or in combination of two or more.

[0131] U 1 -V 1 -W 1 -X 1 -Y 1 -X 2 -Y 2 -X 3 -W 2 -V 2 -U 2 (A)

[0132] In formula (A),

[0133] X 1 、X 2 and X 3 Each of X and X represents independently a 1,4-phenylene group which may have a substituent or a cyclohexane-1,4-diyl group which may have a substituent. 1 、X 2 and X 3At least one of the groups is a 1,4-phenylene group which may have a substituent. -CH2- in the cyclohexane-1,4-diyl group may be substituted with -O-, -S-, or -NR-. R represents an alkyl group having 1 to 6 carbon atoms or a phenyl group.

[0134] Y 1 and Y 2 independently represent -CH2CH2-, -CH2O-, -COO-, -OCOO-, a single bond, -N=N-, -CR a =CR b -, -C≡C- or -CR a =N-. R a and R b Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[0135] U 1 represents a hydrogen atom or a polymerizable group.

[0136] U 2 represents a polymerizable group.

[0137] W 1 and W 2 independently of one another represent a single bond, -O-, -S-, -COO- or -OCOO-.

[0138] V 1 and V 2 Each independently represents an alkanediyl group having 1 to 20 carbon atoms which may have a substituent, wherein -CH2- constituting the alkanediyl group may be substituted with -O-, -S- or -NH-.

[0139] In compound (A), X 1 、X 2 and X 3 At least one of them is preferably 1,4-phenylene which may have a substituent.

[0140] The 1,4-phenylene group which may have a substituent is preferably unsubstituted. The cyclohexane-1,4-diyl group which may have a substituent is preferably a trans-cyclohexane-1,4-diyl group which may have a substituent, and the trans-cyclohexane-1,4-diyl group which may have a substituent is preferably unsubstituted.

[0141] Examples of the substituent that the optionally substituted 1,4-phenylene group or the optionally substituted cyclohexane-1,4-diyl group may have include alkyl groups having 1 to 4 carbon atoms, such as methyl, ethyl, and butyl groups, cyano groups, and halogen atoms.

[0142] Y 1 Preferably -CH2CH2-, -COO- or a single bond, Y 2Preferred is -CH2CH2- or -CH2O-.

[0143] U 2 U is a polymerizable group. 1 is a hydrogen atom or a polymerizable group, preferably a polymerizable group. 1 and U 2 Preferably, all of them are polymerizable groups, and more preferably, all of them are photopolymerizable groups. A polymerizable liquid crystal compound having a photopolymerizable group is advantageous in that it can be polymerized at a lower temperature.

[0144] U 1 and U 2 The polymerizable groups shown may be different from each other, but are preferably the same. Examples of the polymerizable groups include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloyloxy, methacryloyloxy, oxiranyl, and oxetanyl. Among them, acryloyloxy, methacryloyloxy, vinyloxy, oxiranyl, and oxetanyl are preferred, and acryloyloxy is more preferred.

[0145] As V 1 and V 2 Examples of the alkane diyl group include methylene, ethylene, propane-1,3-diyl, butane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, decane-1,10-diyl, tetradecane-1,14-diyl, and eicosane-1,20-diyl. 1 and V 2 An alkanediyl group having 2 to 12 carbon atoms is preferred, and an alkanediyl group having 6 to 12 carbon atoms is more preferred.

[0146] Examples of the substituent that the optionally substituted alkanediyl group having 1 to 20 carbon atoms may have include a cyano group and a halogen atom. The alkanediyl group is preferably unsubstituted, and more preferably an unsubstituted linear alkanediyl group.

[0147] W 1 and W 2 Independently of each other, they are preferably a single bond or -O-.

[0148] Specific examples of compound (A) include non-coloring polymerizable liquid crystal compounds represented by formula (1-1) to formula (1-23). ​​When compound (A) has a cyclohexane-1,4-diyl group, the cyclohexane-1,4-diyl group is preferably a trans isomer.

[0149] [Chemical Formula 3]

[0150]

[0151] [Chemical Formula 4]

[0152]

[0153] [Chemical Formula 5]

[0154]

[0155] Among the exemplified compounds (A), at least one selected from the group consisting of compounds represented by Formula (1-2), Formula (1-3), Formula (1-4), Formula (1-6), Formula (1-7), Formula (1-8), Formula (1-13), Formula (1-14), and Formula (1-15) is preferred.

[0156] The exemplified compounds (A) can be used in polarizers alone or in combination. When combining two or more polymerizable liquid crystal compounds, it is preferred that at least one compound be (A), and more preferably two or more compounds be (A). Combining two or more polymerizable liquid crystal compounds can sometimes temporarily maintain liquid crystallinity even at temperatures below the liquid crystal-crystal phase transition temperature. The mixing ratio when combining two polymerizable liquid crystal compounds is typically 1:99 to 50:50, preferably 5:95 to 40:60, and more preferably 10:90 to 30:70.

[0157] Compound (A) can be produced by a known method such as that described in Lub et al. Recl. Trav. Chim. Pays-Bas, 115, 321-328 (1996) or Japanese Patent No. 4719156.

[0158] The content of the polymerizable liquid crystal compound in the polarizer forming composition is preferably 80% by mass or more, more preferably 82% by mass or more relative to the solid content of the polarizer forming composition, preferably 99.5% by mass or less, more preferably 99% by mass or less, further preferably 94% by mass or less, particularly preferably 90% by mass or less. If the content of the polymerizable liquid crystal compound is within the above range, there is a tendency for orientation to become higher. Here, solid content refers to the total amount of the components after removing the solvent from the polarizer forming composition. Thus, the cured product layer of the obtained polarizer forming composition contains a polymer of a polymerizable liquid crystal compound preferably 80% by mass or more, more preferably 82% by mass or more, preferably 99.5% by mass or less, more preferably 99% by mass or less, further preferably 94% by mass or less, particularly preferably 90% by mass or less relative to the total mass of the cured product layer.

[0159] (Compounds exhibiting dichroism)

[0160] The dichroic compound contained in the polarizer-forming composition refers to a compound that exhibits the following property (dichroism): the absorbance along the long axis of the molecule is different from the absorbance along the short axis. In a preferred embodiment of the present invention, from the perspective of easily controlling the orientation, the dichroic compound is oriented with the polymer of the polymerizable liquid crystal compound and included in the cured layer of the polarizer-forming composition. It should be noted that in a more preferred embodiment of the present invention, if the cured layer of the polymerizable liquid crystal composition contains a polymer of the polymerizable liquid crystal compound in an amount greater than the above range (e.g., 80% by mass or greater) relative to the total mass of the cured layer, and the polymer of the polymerizable liquid crystal compound exhibits a smectic liquid crystal phase, and the dichroic compound is oriented with the polymer of the polymerizable liquid crystal compound and included in the cured layer, the orientation is further improved, resulting in high polarization characteristics.

[0161] As a compound showing dichroism, it is preferable to have an absorption maximum wavelength (λ) in the range of 300 to 700 nm. max ) compounds. Examples of such dichroic compounds include acridine pigments, oxazine pigments, cyanine pigments, naphthalene pigments, azo pigments, and anthraquinone pigments, with azo pigments being preferred. Examples of azo pigments include monoazo pigments, disazo pigments, triazo pigments, tetrazo pigments, and stilbene azo pigments, with disazo pigments and triazo pigments being preferred. The dichroic compound may be a single species or a combination of two or more species, but a combination of three or more species is preferred. In particular, a combination of three or more azo compounds is more preferred.

[0162] Examples of the azo dye include compounds represented by formula (B) (hereinafter referred to as “compound (B)” depending on the case).

[0163] A 1 (-N = NA 2 ) p -N=NA 3 (B)

[0164] In formula (B),

[0165] A 1 and A 3 A represents independently of each other a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or a monovalent heterocyclic group which may have a substituent. 2 represents a 1,4-phenylene group which may have a substituent, a naphthalene-1,4-diyl group which may have a substituent, or a divalent heterocyclic group which may have a substituent. p represents an integer from 1 to 4. When p is an integer of 2 or more, a plurality of A 2 They can be the same as or different from each other.

[0166] Examples of the monovalent heterocyclic group include groups obtained by removing one hydrogen atom from heterocyclic compounds such as quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole, and benzoxazole. Examples of the divalent heterocyclic group include groups obtained by removing two hydrogen atoms from the above heterocyclic compounds.

[0167] As A 1 and A 3 The phenyl, naphthyl and monovalent heterocyclic groups, and A 2 The substituents optionally possessed by the p-phenylene group, naphthalene-1,4-diyl group, and divalent heterocyclic group include: alkyl groups having 1 to 4 carbon atoms; alkoxy groups having 1 to 4 carbon atoms, such as methoxy, ethoxy, and butoxy; fluoroalkyl groups having 1 to 4 carbon atoms, such as trifluoromethyl; cyano; nitro; halogen atoms; substituted or unsubstituted amino groups, such as amino, diethylamino, and pyrrolidinyl (a substituted amino group refers to an amino group having one or two alkyl groups having 1 to 6 carbon atoms, or an amino group in which two substituted alkyl groups are bonded to form an alkanediyl group having 2 to 8 carbon atoms; an unsubstituted amino group is -NH2). Specific examples of the alkyl group having 1 to 6 carbon atoms include methyl, ethyl, butyl, and hexyl groups.

[0168] Among the compounds (B), preferred are compounds represented by the following formulae (2-1) to (2-6).

[0169] [Chemical Formula 6]

[0170]

[0171] In formulas (2-1) to (2-6),

[0172] B 1 ~B 20 Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkylcarboxylate group having 1 to 6 carbon atoms, a cyano group, a nitro group, a substituted or unsubstituted amino group (the definitions of the substituted amino group and the unsubstituted amino group are as described above), a chlorine atom or a trifluoromethyl group.

[0173] n1 to n4 independently represent integers of 0 to 3.

[0174] When n1 is 2 or more, multiple B 2 can be the same or different from each other,

[0175] When n2 is greater than 2, multiple B 6 can be the same or different from each other,

[0176] When n3 is 2 or more, multiple B 9 can be the same or different from each other,

[0177] When n4 is 2 or more, multiple B 14 They may be the same as or different from each other.

[0178] As the anthraquinone dye, a compound represented by formula (2-7) is preferable.

[0179] [Chemical Formula 7]

[0180]

[0181] In formula (2-7),

[0182] R 1 ~R 8 independently represent hydrogen atoms, -R x 、-NH2、-NHR x 、-NR x 2. -SR x or halogen atoms.

[0183] R x It represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.

[0184] As the oxazine dye, a compound represented by formula (2-8) is preferred.

[0185] [Chemical Formula 8]

[0186]

[0187] In formula (2-8),

[0188] R 9 ~R 15 independently represent hydrogen atoms, -R x 、-NH2、-NHR x 、-NR x 2. -SR x or halogen atoms.

[0189] R x It represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.

[0190] As the acridine dye, a compound represented by formula (2-9) is preferable.

[0191] [Chemical Formula 9]

[0192]

[0193] In formula (2-9),

[0194] R 16 ~R 23 independently represent hydrogen atoms, -Rx 、-NH2、-NHR x 、-NR x 2. -SR x or halogen atoms.

[0195] R x It represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.

[0196] As R in formula (2-7), formula (2-8) and formula (2-9) x Examples of the alkyl group having 1 to 4 carbon atoms include methyl, ethyl, propyl, butyl, pentyl and hexyl. Examples of the aryl group having 6 to 12 carbon atoms include phenyl, toluoyl, xylyl and naphthyl.

[0197] As the cyanine dye, the compound represented by formula (2-10) and the compound represented by formula (2-11) are preferred.

[0198] [Chemical Formula 10]

[0199]

[0200] In formula (2-10),

[0201] D 1 and D 2 Each independently represents a group represented by any of Formula (2-10a) to Formula (2-10d).

[0202] [Chemical Formula 11]

[0203]

[0204] n5 represents an integer from 1 to 3.

[0205] [Chemical Formula 12]

[0206]

[0207] In formula (2-11),

[0208] D 3 and D 4 Each independently represents a group represented by any of Formula (2-11a) to Formula (2-11h).

[0209] [Chemical Formula 13]

[0210]

[0211] n6 represents an integer from 1 to 3.

[0212] When the total mass of the polymerizable liquid crystal compound is set to 100 parts by mass, the content of the compound showing dichroism in the polarizer forming composition is preferably 0.1 to 30 parts by mass relative to the total mass, more preferably 0.1 to 20 parts by mass, and further preferably 0.1 to 12 parts by mass. If the content of the compound showing dichroism is within the aforementioned range, the polymerizable liquid crystal compound can be polymerized without disturbing the orientation of the polymerizable liquid crystal compound. If the content of the compound showing dichroism is too much, there is a risk of hindering the orientation of the polymerizable liquid crystal compound. Therefore, the content of the compound showing dichroism can also be determined within the range in which the polymerizable liquid crystal compound can maintain a liquid crystal state. It should be noted that, from the same viewpoint as above, the content of the compound showing dichroism in the cured material layer of the obtained polarizer forming composition is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the polymer of the polymerizable liquid crystal compound, more preferably 0.1 to 20 parts by mass, and further preferably 0.1 to 12 parts by mass.

[0213] The compound showing dichroism can be a polymer having a polymerizable group and a monomer with the above-mentioned pigment as a skeleton. In the case where the compound showing dichroism is a polymer having a polymerizable group and a monomer with the above-mentioned pigment as a skeleton, the compound showing dichroism can be further suppressed from migrating to the first resin layer. However, if the compound showing dichroism is a polymer, there is a tendency for the orientation to become lower, and therefore there is a tendency for the polarization performance to decrease. Therefore, in a preferred embodiment of the present invention, the compound showing dichroism does not have a polymerizable group, and its molecular weight is, for example, less than 1000. According to the present invention, even if the compound showing dichroism is not polymerized, the migration of the compound showing dichroism to the first resin layer can be suppressed, and therefore a polarizing plate with excellent polarization performance can be obtained.

[0214] The polarizing plate forming composition may contain a solvent, a polymerization initiator, a sensitizer, a polymerization inhibitor, a leveling agent, and a reactive additive as components other than the polymerizable liquid crystal compound and the compound exhibiting dichroism.

[0215] (Solvent)

[0216] The polarizing plate forming composition may contain a solvent. As the solvent, preferably, a solvent that can completely dissolve the polymerizable liquid crystal compound and is inactive in the polymerization reaction of the polymerizable liquid crystal compound is preferable.

[0217] Examples of the solvent include: alcohol solvents such as methanol, ethanol, ethylene glycol, isopropanol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, and propylene glycol monomethyl ether; ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, and ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, methyl isobutyl ketone, and isophorone; aliphatic hydrocarbon solvents such as pentane, hexane, and heptane; aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; chlorinated solvents such as chloroform and chlorobenzene, etc. These solvents may be used alone or in combination of two or more.

[0218] The content of the solvent is preferably 50 to 98% by mass relative to the total mass of the polarizer-forming composition. In other words, the content of the solid component in the polarizer-forming composition is preferably 2 to 50% by mass. If the content of the solid component is 50% by mass or less, the viscosity of the polarizer-forming composition decreases, so that the thickness of the cured layer of the polarizer-forming composition becomes roughly uniform, thereby having a tendency to be less prone to unevenness in the polarizer. In addition, the content of the solid component can be determined by considering the thickness of the cured layer of the polarizer-forming composition to be manufactured.

[0219] (Polymerization initiator)

[0220] The polarizer-forming composition may contain a polymerization initiator. A polymerization initiator is a compound that can initiate a polymerization reaction of a polymerizable liquid crystal compound, etc. As the polymerization initiator, a photopolymerization initiator that generates active radicals by the action of light is preferred.

[0221] Examples of polymerization initiators that can be used in the polarizer-forming composition include the same polymerization initiators as those exemplified as the polymerization initiators that can be used in the first resin layer-forming composition.

[0222] When the polarizer-forming composition contains a polymerization initiator, its content can be appropriately adjusted according to the type and amount of the polymerizable liquid crystal compound. However, when the total mass of the polymerizable liquid crystal compound is 100 parts by mass, the content of the polymerization initiator is generally 0.1 to 30 parts by mass, preferably 0.5 to 10 parts by mass, and more preferably 0.5 to 8 parts by mass. If the content of the polymerization initiator is within the above range, polymerization can be carried out without disturbing the orientation of the polymerizable liquid crystal compound.

[0223] (Sensitizer)

[0224] The polarizer-forming composition may contain a sensitizer. A photosensitizer is preferred. Examples of such sensitizers include xanthone compounds such as xanthone and thioxanthone (e.g., 2,4-diethylthioxanthone, 2-isopropylthioxanthone); anthracene compounds such as anthracene and anthracene containing an alkoxy group (e.g., dibutoxyanthracene); phenothiazine, and rubrene. These sensitizers may be used alone or in combination of two or more.

[0225] When the polarizer-forming composition contains a sensitizer, the polymerization reaction of the polymerizable liquid crystal compound contained in the polarizer-forming composition can be further promoted. The amount of the sensitizer used is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 0.5 to 8 parts by mass, relative to 100 parts by mass of the total mass of the polymerizable liquid crystal compound.

[0226] (Polymerization inhibitor)

[0227] The polarizing plate forming composition may contain a polymerization inhibitor from the viewpoint of stably progressing the polymerization reaction. The polymerization inhibitor can control the degree of progress of the polymerization reaction of the polymerizable liquid crystal compound.

[0228] Examples of the polymerization inhibitor include hydroquinone, alkoxy-containing hydroquinone, alkoxy-containing catechol (e.g., butylcatechol), pyrogallol, and radical scavengers such as 2,2,6,6-tetramethyl-1-piperidinyloxy radicals; thiophenols; β-naphthylamines; and β-naphthols. These polymerization inhibitors may be used alone or in combination of two or more.

[0229] When the polarizer-forming composition contains a polymerization inhibitor, the content of the polymerization inhibitor is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 0.5 to 8 parts by mass, relative to 100 parts by mass of the total mass of the polymerizable liquid crystal compound. When the content of the polymerization inhibitor is within the above range, polymerization can be performed without disturbing the alignment of the polymerizable liquid crystal compound.

[0230] (Leveling agent)

[0231] The polarizer-forming composition may contain a leveling agent. A leveling agent adjusts the fluidity of the polarizer-forming composition and makes the film formed by coating the polarizer-forming composition smoother. Examples of such agents include surfactants. Preferred leveling agents include those containing polyacrylate compounds as their primary component, such as BYK-361N (manufactured by BYK-Chemie), and those containing fluorine-containing compounds as their primary component, such as Surflon (registered trademark) S-381 (manufactured by AGC Semichemical Co., Ltd.), MEGAFACE F-556, and MEGAFACE F-554 (manufactured by DIC Corporation).

[0232] When the polarizer-forming composition contains a leveling agent, the content of the leveling agent relative to the total mass of the polymerizable liquid crystal compound is preferably 0.1 to 5 parts by mass, more preferably 0.3 to 5 parts by mass, and even more preferably 0.4 to 3 parts by mass, when the total mass of the polymerizable liquid crystal compound is 100 parts by mass. If the content of the leveling agent is within the above range, the polymerizable liquid crystal compound is easily aligned in the horizontal direction (horizontal alignment), and there is a tendency for the cured layer of the resulting polarizer-forming composition to be smoother. If the content of the leveling agent relative to the polymerizable liquid crystal compound exceeds the above range, there is a tendency for unevenness to occur in the cured layer of the resulting polarizer-forming composition. It should be noted that the polarizer-forming composition may contain one or more leveling agents.

[0233] (Reactive Additives)

[0234] The polarizer-forming composition may contain a reactive additive. The reactive additive preferably has a carbon-carbon unsaturated bond and an active hydrogen-reactive group in its molecule. It should be noted that the "active hydrogen-reactive group" referred to herein refers to a group reactive toward groups having active hydrogen, such as a carboxyl group (-COOH), a hydroxyl group (-OH), and an amino group (-NH2). Representative examples include a glycidyl group, an oxazoline group, a carbodiimide group, an aziridine group, an imide group, an isocyanate group, an isothiocyanate group, and a maleic anhydride group. The number of carbon-carbon unsaturated bonds and active hydrogen-reactive groups possessed by the reactive additive is typically 1 to 20, and preferably 1 to 10, respectively.

[0235] It is preferred that at least two active hydrogen-reactive groups exist in the reactive additive. In this case, the plurality of active hydrogen-reactive groups present may be the same or different.

[0236] The carbon-carbon unsaturated bond possessed by the reactive additive may be a carbon-carbon double bond, a carbon-carbon triple bond, or a combination thereof, but is preferably a carbon-carbon double bond. Reactive additives preferably contain carbon-carbon unsaturated bonds in the form of vinyl groups and / or (meth)acryloyl groups. Reactive additives preferably have at least one selected from the group consisting of epoxy groups, glycidyl groups, and isocyanate groups as their active hydrogen-reactive groups, and more preferably have both acryloyl groups and isocyanate groups.

[0237] Specific examples of reactive additives include compounds having a (meth)acryloyl group and an epoxy group, such as methacryloyloxyglycidyl ether or acryloyloxyglycidyl ether; compounds having a (meth)acryloyl group and an oxetane group, such as oxetane acrylate or oxetane methacrylate; compounds having a (meth)acryloyl group and a lactone group, such as lactone acrylate or lactone methacrylate; compounds having a vinyl group and an oxazoline group, such as vinyloxazoline or isopropenyloxazoline; and oligomers of compounds having a (meth)acryloyl group and an isocyanate group, such as isocyanatomethyl acrylate, isocyanatomethyl methacrylate, 2-isocyanatoethyl acrylate, and 2-isocyanatoethyl methacrylate. Furthermore, compounds having a vinyl group or a vinylidene group and an acid anhydride, such as methacrylic anhydride, acrylic anhydride, maleic anhydride, and vinylmaleic anhydride, can also be mentioned. Among them, preferred are methacryloyloxy glycidyl ether, acryloyloxy glycidyl ether, isocyanatomethyl acrylate, isocyanatomethyl methacrylate, vinyloxazoline, 2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate and oligomers thereof, and particularly preferred are isocyanatomethyl acrylate, 2-isocyanatoethyl acrylate and oligomers thereof.

[0238] Specifically, a compound represented by the following formula (Y) is preferred.

[0239] [Chemical Formula 14]

[0240]

[0241] In formula (Y),

[0242] n represents an integer from 1 to 10, R 1’ represents a divalent aliphatic or alicyclic hydrocarbon group having 2 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 5 to 20 carbon atoms. 2’ , one is -NH-, the other is>NC(=O)-R 3’ The group represented by R 3’ represents a hydroxyl group or a group having a carbon-carbon unsaturated bond.

[0243] R in formula (Y)3’ At least one R 3’ It is a group having a carbon-carbon unsaturated bond.

[0244] Among the reactive additives represented by the above formula (Y), compounds represented by the following formula (YY) (hereinafter sometimes referred to as compound (YY)) are particularly preferred (where n has the same meaning as described above).

[0245] [Chemical Formula 15]

[0246]

[0247] Compound (YY) may be a commercially available product as it is or may be purified as needed. Examples of commercially available products include Laromer (registered trademark) LR-9000 (manufactured by BASF).

[0248] When the polarizing plate forming composition contains a reactive additive, the content of the reactive additive is usually 0.01 to 10 parts by mass, preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the total mass of the polymerizable liquid crystal compound.

[0249] (Oriented film)

[0250] When the polarizing plate is composed of two layers, the polarizing plate is composed of a cured product layer of the polarizing plate-forming composition and an alignment film adjacent thereto.

[0251] In the present invention, the alignment film is a film formed of a polymer compound, and is a film having an alignment regulating force for orienting a polymerizable liquid crystal compound in a desired direction.

[0252] The alignment film facilitates the liquid crystal orientation of the polymerizable liquid crystal compound. The state of liquid crystal orientation, such as horizontal alignment, vertical alignment, mixed alignment, and tilted alignment, varies depending on the properties of the alignment film and the polymerizable liquid crystal compound, and any combination thereof can be selected. For example, if the alignment film is made of a material that exhibits horizontal alignment as an alignment restraining force, the polymerizable liquid crystal compound can form a horizontal alignment or a mixed alignment. If the alignment film is made of a material that exhibits vertical alignment as an alignment restraining force, the polymerizable liquid crystal compound can form a vertical alignment or a tilted alignment. Expressions such as horizontal and vertical indicate the direction of the long axis of the oriented polymerizable liquid crystal compound relative to the polarizer plane. For example, vertical alignment means that the long axis of the oriented polymerizable liquid crystal compound is perpendicular to the polarizer plane. The vertical mentioned here means 90°±20° relative to the polarizer plane.

[0253] When the alignment film is formed of an aligning polymer, the alignment restraining force can be arbitrarily adjusted by the surface state or friction conditions. When the alignment film is formed of a photoaligning polymer, the alignment restraining force can be arbitrarily adjusted by polarized light irradiation conditions, etc. Furthermore, the liquid crystal orientation can be controlled by selecting physical properties such as the surface tension and liquid crystallinity of the polymerizable liquid crystal compound.

[0254] The alignment film formed between the second resin layer and the cured layer of the polarizer-forming composition, described later, is preferably insoluble in the solvent used to form the cured layer of the polarizer-forming composition on the alignment film and heat-resistant to the heat treatment used to remove the solvent and align the liquid crystals. Examples of the alignment film include alignment films formed from an aligning polymer, photo-alignment films, and groove alignment films, with photo-alignment films being preferred.

[0255] As the oriented polymer, there can be enumerated: polyamide or gelatin having an amide bond in the molecule, polyimide having an imide bond in the molecule and polyamic acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, polyoxazole, polyethyleneimine, polystyrene, polyvinyl pyrrolidone, polyacrylic acid and polyacrylates etc. as their hydrolysates. Among them, polyvinyl alcohol is preferred. These oriented polymers can be used alone or in combination of two or more.

[0256] When the oriented film is formed by an oriented polymer, the oriented film can generally be obtained by the following process: a process of applying a composition containing an oriented polymer and a solvent (hereinafter also referred to as an "oriented polymer composition") to a second resin layer, a resin film or a surface treatment layer and removing the solvent; or a process of applying the oriented polymer composition to a second resin layer, a resin film or a surface treatment layer and removing the solvent, and then rubbing (rubbing method).

[0257] Examples of the solvent include water; alcohol solvents such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether; ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, and ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone, and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane, and heptane; aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; and chlorine-substituted hydrocarbon solvents such as chloroform and chlorobenzene. These solvents may be used alone or in combination of two or more.

[0258] The concentration of the oriented polymer in the oriented polymer composition may be within a range that allows the oriented polymer to be completely dissolved in the solvent, and is preferably 0.1 to 20% by mass, more preferably 0.1 to 10% by mass, based on the mass of the oriented polymer composition.

[0259] As the oriented polymer composition, a commercially available oriented film material can be used as it is. Examples of commercially available oriented film materials include Sunever (registered trademark) (manufactured by Nissan Chemical Industries, Ltd.) and OPTMER (registered trademark) (manufactured by JSR Corporation).

[0260] Examples of methods for coating the oriented polymer composition on the second resin layer, resin film, or surface treatment layer include spin coating, extrusion coating, gravure coating, die coating, rod coating, and applicator coating, as well as printing methods such as flexographic methods. When the polarizing plate according to one embodiment of the present invention is manufactured using a roll-to-roll continuous manufacturing process, the coating method generally employs a gravure coating method, die coating method, or a printing method such as a flexographic method.

[0261] The solvent contained in the oriented polymer composition is removed to form a dry film of the oriented polymer. Examples of the method for removing the solvent include natural drying, air drying, heat drying, and reduced pressure drying.

[0262] As a method for rubbing, there can be cited a method in which a rubbing roller wound with a rubbing cloth and rotating is brought into contact with a film of an oriented polymer, wherein the film of the oriented polymer is a film formed on the surface of the second resin layer, the resin film or the surface treatment layer by applying an oriented polymer composition to the second resin layer, the resin film or the surface treatment layer and annealing it.

[0263] Photo-alignment films are typically formed by applying a composition containing a polymer or monomer having a photoreactive group and a solvent (hereinafter referred to as a "photo-alignment film-forming composition") to a second resin layer, a resin film, or a surface-treated layer, and then irradiating the composition with polarized light (preferably polarized UV light). Photo-alignment films are more preferred because the direction of the alignment regulating force can be arbitrarily controlled by selecting the polarization direction of the irradiated polarized light.

[0264] A photoreactive group is a group that exhibits liquid crystal alignment properties upon exposure to light. Specifically, it is a group that undergoes photoreactions that originate in the liquid crystal alignment properties, such as molecular alignment induction, isomerization, dimerization, photocrosslinking, or photodecomposition reactions upon exposure to light. Among these photoreactive groups, groups that induce dimerization or photocrosslinking reactions are preferred due to their excellent alignment properties. Photoreactive groups capable of such reactions are preferably those having an unsaturated bond, particularly a double bond, and more preferably those having at least one selected from the group consisting of a carbon-carbon double bond (C=C bond), a carbon-nitrogen double bond (C=N bond), a nitrogen-nitrogen double bond (N=N bond), and a carbon-oxygen double bond (C=O bond).

[0265] Examples of photoreactive groups having a C=C bond include vinyl, polyenyl, stilbenyl, stilbazolyl, stilbazolyl, cinnamoyl, and the like. Examples of photoreactive groups having a C=N bond include groups having structures such as aromatic Schiff bases and aromatic hydrazones. Examples of photoreactive groups having an N=N bond include azophenyl, azonaphthyl, aromatic heterocyclic azo groups, disazo groups, and formazan groups, as well as groups based on azobenzene oxide. Examples of photoreactive groups having a C=O bond include benzophenone, coumarin, anthraquinone, and maleimide groups. These groups may have a substituent such as an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group, or a haloalkyl group.

[0266] The solvent of the photo-alignment film-forming composition is preferably a solvent that dissolves the polymer and monomer having a photoreactive group. Examples of such a solvent include the solvents listed as examples of the solvent for the alignment polymer composition.

[0267] The content of the polymer or monomer having a photoreactive group relative to the photo-alignment film-forming composition can be adjusted appropriately depending on the type of polymer or monomer having a photoreactive group and the desired thickness of the photo-alignment film, but is preferably 0.2% by mass or greater, and particularly preferably within the range of 0.3% to 10% by mass. Furthermore, the photo-alignment film-forming composition may contain a polymer material such as polyvinyl alcohol or polyimide, as well as a photosensitizer, within a range that does not significantly impair the properties of the photo-alignment film.

[0268] The method for applying the photo-alignment film-forming composition to the second resin layer, resin film, or surface-treated layer may be the same method as the method for applying the oriented polymer composition to the second resin layer, resin film, or surface-treated layer. The method for removing the solvent from the applied photo-alignment film-forming composition may be the same method as the method for removing the solvent from the oriented polymer composition.

[0269] When irradiating polarized light, it can be in a form where polarized light is directly irradiated onto a substance obtained by removing a solvent from a composition for forming a photo-alignment film coated on a second resin layer, a resin film, a surface treatment layer, etc., or in a form where polarized light is irradiated from the second resin layer side, the resin film side, or the surface treatment layer side and the polarized light is transmitted for irradiation. Additionally, it is particularly preferred that this polarized light is substantially parallel light. The wavelength of the irradiated polarized light can be a wavelength in the wavelength region where the photo-reactive groups of a polymer or monomer having photo-reactive groups can absorb light energy. Specifically, UV (ultraviolet light) with a wavelength in the range of from 250 to 400 nm is particularly preferred. As a light source for this polarized light irradiation, examples include xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, ultraviolet lasers such as KrF and ArF, and more preferably high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps. These lamps are preferred because the luminous intensity of ultraviolet light with a wavelength of 313 nm is large. By passing the light from the above light source through an appropriate polarizer and then irradiating, polarized light can be irradiated. As this polarizer, the following can be used: polarizing filters, polarizing prisms such as Glan-Thompson and Glan-Taylor prisms, and wire grid type polarizers.

[0270] It should be noted that when performing rubbing or polarized light irradiation, if masking is carried out, it is also possible to form multiple regions (patterns) with different directions of liquid crystal alignment.

[0271] A groove alignment film is a film having an uneven pattern or multiple grooves (slots) on the film surface. When liquid crystal molecules are placed on a film having multiple linear grooves arranged at equal intervals, the liquid crystal molecules are aligned in the direction along the groove.

[0272] As methods for obtaining a groove alignment film, examples include: a method of forming an uneven pattern by performing exposure on the surface of a photosensitive polyimide film through an exposure mask having a pattern-shaped slit and then performing development and rinsing processes; a method of forming a layer of a pre-cured UV curable resin on a plate-shaped original plate (Japanese: 原盤) having grooves on its surface, transferring the resin layer to a second resin layer, a resin film, or a surface treatment layer, and then curing; and a method of pressing a roller-shaped original plate having multiple grooves against a film of a pre-cured UV curable resin formed on a second resin layer, a resin film, or a surface treatment layer to form unevenness, and then curing. Specifically, examples include the methods described in Japanese Patent Laid-Open No. 6-34976 and Japanese Patent Laid-Open No. 2011-2427 for 43.

[0273] In order to obtain an alignment with little alignment disorder, the width of the convex portion of the groove alignment film is preferably from 0.05 μm to 5 μm, the width of the concave portion is preferably from 0.1 μm to 5 μm, and the depth of the height difference between the unevenness is preferably 2 μm or less, and more preferably from 0.01 μm to 1 μm.

[0274] <Second resin layer>

[0275] In one embodiment of the present invention, the polarizing plate further contains a second resin layer on the side opposite to the first resin layer of the polarizer, and preferably further contains a second resin layer adjacent thereto. The second resin layer is a cured layer of a curable resin composition containing a free radical polymerizable compound (hereinafter also referred to as a "second resin layer forming composition"). The cured layer (cured film) of the second resin layer forming composition refers to a layer obtained by polymerizing the polymerizable compound contained in the coating film after applying the second resin layer forming composition to obtain a coating film, that is, the cured layer of the second resin layer forming composition is a layer formed by a polymer containing the polymerizable compound. If the polarizing plate contains a second resin layer, the mechanical strength of the polarizing plate is improved, and the operability can be made excellent. The second resin layer may have the same or different composition or thickness as the first resin layer.

[0276] Specific examples of the radically polymerizable compound contained in the second resin layer-forming composition include monofunctional (meth)acrylates, polyfunctional (meth)acrylates, and urethane acrylates. The second resin layer-forming composition preferably contains one or more polyfunctional (meth)acrylates and one or more urethane acrylates. In the present invention, the cured layer of the second resin layer-forming composition, i.e., the second resin layer, is a layer obtained by curing (polymerizing) a coating film obtained by coating the second resin layer-forming composition on a polarizer or a release film. The cured layer of the second resin layer-forming composition preferably contains a polymer comprising structural units derived from a polyfunctional (meth)acrylate and structural units derived from a urethane acrylate.

[0277] Therefore, in a preferred embodiment when the polarizing plate includes (preferably includes adjacent to) a second resin layer on the side opposite to the first resin layer of the polarizer, the second resin layer is a cured layer of a curable resin composition containing a polyfunctional (meth)acrylate and a urethane acrylate.

[0278] The polyfunctional (meth)acrylate and urethane acrylate contained in the second resin layer-forming composition, and the monofunctional (meth)acrylate that may be contained optionally, can be the compounds described above as examples of the polyfunctional (meth)acrylate, urethane acrylate, and monofunctional (meth)acrylate contained in the first resin layer-forming composition.

[0279] The second resin layer-forming composition may contain a solvent. By including a solvent in the second resin layer-forming composition, the fluidity of the second resin layer-forming composition is further improved, thereby enabling the second resin layer-forming composition to be applied more uniformly and thinly, resulting in a second resin layer with a more uniform and thinner thickness. Examples of solvents that can be used in the second resin layer-forming composition include the same solvents as those previously exemplified as examples of solvents that can be used in the first resin layer-forming composition.

[0280] The second resin layer-forming composition may contain one or more additives commonly used in curable compositions, as needed. Such additives may be any additives that can be contained in the first resin layer-forming composition, and preferably, additives that are suitable for inclusion in the first resin layer-forming composition may also be used.

[0281] The thickness of the second resin layer is not particularly limited, but is generally 10 μm or less, preferably 0.15 to 5 μm, more preferably 0.5 to 4 μm, and even more preferably 1.0 to 3 μm.

[0282] The polarizing plate of the present invention has excellent durability under high temperature conditions (i.e., heat resistance) and / or durability under high humidity conditions. Heat resistance refers to the polarization performance of the polarizing plate being less susceptible to changes over time under high temperature conditions, while durability under high humidity conditions refers to the polarization performance of the polarizing plate being less susceptible to changes over time under high humidity conditions.

[0283] For example, after being held at 105°C dry in an atmospheric atmosphere for 65 hours, the change in the visual sensitivity-corrected polarization degree Py (polarization change) is preferably 10% or less, more preferably 5% or less, and even more preferably 4% or less, based on the visual sensitivity-corrected polarization degree Py before holding. The change in the visual sensitivity-corrected single transmittance Ty (single transmittance change) after being held under the same conditions for 1 hour is preferably 10% or less, more preferably 5% or less, and even more preferably 4% or less, based on the visual sensitivity-corrected single transmittance Ty before holding. In the method of manufacturing a display device using a polarizing plate, a step of applying heat to the polarizing plate is sometimes performed. This step can degrade the polarization performance of the polarizing plate. However, due to the excellent heat resistance of the polarizing plate of the present invention, deterioration of the polarization performance is less likely to occur during the display device manufacturing process, resulting in a display device with excellent image display function.

[0284] For example, after being stored at 105°C dry in an air atmosphere for 65 hours, the change in the visual sensitivity-corrected polarization degree Py (polarization change) is preferably 10% or less, more preferably 5% or less, and even more preferably 4% or less, based on the visual sensitivity-corrected polarization degree Py before storage. The change in the visual sensitivity-corrected single transmittance Ty after being stored under the same conditions for 1 hour (single transmittance change) is preferably 10% or less, more preferably 5% or less, and even more preferably 4% or less, based on the visual sensitivity-corrected single transmittance Ty before storage. It should be noted that the lower limits of the polarization change and the single transmittance change are generally 0% or greater.

[0285] The visual sensitivity-corrected single transmittance (Ty) and the visual sensitivity-corrected polarization degree (Py) in this specification can be measured as follows.

[0286] Using a spectrophotometer (Shimadzu UV-3150) equipped with a holder equipped with a polarizing element, the transmittance along the transmission axis (Ta) and the transmittance along the absorption axis (Tb) were measured using the double-beam method within the wavelength range of 380 nm to 780 nm. A grid that cuts off 50% of the light was previously placed on the reference side of the holder. The single-element transmittance at each wavelength was calculated using the following formula. Furthermore, visual sensitivity correction was performed using the 2-degree field of view (illuminant C) according to JIS Z 8701 to calculate the visual sensitivity-corrected single-element transmittance (Ty).

[0287] Single body transmittance (%) = (Ta + Tb) / 2

[0288] The polarization degree at each wavelength was calculated using the following formula: Furthermore, visual sensitivity correction was performed using a 2-degree field of view (light source C) according to JIS Z 8701, and the visual sensitivity-corrected polarization degree (Py) was calculated.

[0289] Polarization degree (%) = {(Ta-Tb) / (Ta+Tb)} × 100

[0290] The change in the visual sensitivity correction single transmittance Ty is the difference in Ty before and after the environmental test, and the change in the visual sensitivity correction polarization degree Py is the difference in Py before and after the environmental test.

[0291] [Method for Manufacturing Polarizing Plate]

[0292] The polarizing plate can be manufactured by the following method, which comprises applying the composition in sequence according to the laminated structure, optionally drying the resulting coating, and polymerizing the polymerizable compound contained in the resulting coating. For example, a polarizing plate having a laminated structure of a resin film / first resin layer / polarizing film / photo-alignment film / second resin layer can be manufactured by the following method:

[0293] A coating step of coating the second resin layer-forming composition containing a polymerizable compound on a release film to form a coating film;

[0294] A drying step of drying the coating film;

[0295] A step of polymerizing the polymerizable compound contained in the second resin layer-forming composition;

[0296] A coating step of coating a photo-alignment film-forming composition containing a polymerizable compound on the second resin layer to form a coating film;

[0297] A drying step of drying the coating film;

[0298] A step of polymerizing the polymerizable compound contained in the photo-alignment film-forming composition;

[0299] A coating step of coating a polymerizable liquid crystal composition (polarizer-forming composition) containing a dichroic compound and a polymerizable liquid crystal compound on the photo-alignment film to form a coating film;

[0300] A drying step of drying the coating film;

[0301] A step of polymerizing the polymerizable compound contained in the polarizer-forming composition;

[0302] A coating step of coating the first resin layer-forming composition containing a polymerizable compound on a polarizing film to form a coating film;

[0303] A drying step of optionally drying the coating film;

[0304] a step of laminating a resin film on the coating film of the first resin layer-forming composition and then polymerizing the polymerizable compound contained in the first resin layer-forming composition; and

[0305] ·The process of removing the release film.

[0306] The polymerizable compound is polymerized, whereby the coating film is cured.

[0307] In the polymerization step, the polymerizable compound may be polymerized by heating or irradiation with active energy rays. In a preferred embodiment of the present invention, the polymerizable compound is polymerized by irradiation with active energy rays in order to improve the polarization performance and heat resistance of the resulting polarizing plate. Examples of active energy rays include ultraviolet rays and electron beams.

[0308] In a preferred embodiment of the present invention, the step of drying the coating film of the first resin layer-forming composition is omitted. In the aforementioned exemplary method, performing a drying step (heating step) during the preparation of the first resin layer can disrupt the orientation of the dichroic compound contained in the polarizer. However, in this embodiment, the step of drying the coating film of the first resin layer-forming composition is omitted, thereby eliminating the possibility of orientation disruption caused by heating and the resulting reduction in the polarization performance and heat resistance of the polarizing plate. Drying may be performed, for example, preferably by heating at a temperature of 40°C or below.

[0309] A polarizing plate having a laminated structure of a resin film / first resin layer / polarizing film / photo-alignment film / second resin layer can also be produced by a method different from the above, including the following steps:

[0310] A coating step of coating the first resin layer-forming composition containing a polymerizable compound on a resin film to form a coating film;

[0311] A drying step of optionally drying the coating film;

[0312] A coating step of coating the second resin layer-forming composition containing a polymerizable compound on a release film to form a coating film;

[0313] A drying step of drying the coating film;

[0314] A step of polymerizing the polymerizable compound contained in the second resin layer-forming composition;

[0315] A coating step of coating a photo-alignment film-forming composition containing a polymerizable compound on the second resin layer to form a coating film;

[0316] A drying step of drying the coating film;

[0317] A step of polymerizing the polymerizable compound contained in the photo-alignment film-forming composition;

[0318] A coating step of coating a polymerizable liquid crystal composition (polarizer-forming composition) containing a dichroic compound and a polymerizable liquid crystal compound on the photo-alignment film to form a coating film;

[0319] A drying step of drying the coating film;

[0320] A step of polymerizing the polymerizable compound contained in the polarizer-forming composition;

[0321] A step of laminating a laminated structure consisting of a resin film / a coating film of a composition for forming a first resin layer and a laminated structure consisting of a cured layer of a composition for forming a polarizer / a photo-alignment film / a second resin layer / a release film so that the coating film of the composition for forming a first resin layer and the cured layer of the composition for forming a polarizer are adjacent to each other;

[0322] a step of polymerizing the polymerizable compound contained in the first resin layer-forming composition; and

[0323] ·The process of removing the release film.

[0324] In the above-exemplified methods, an adherend such as a phase difference plate or a display device body may be used instead of a release film, or a phase difference plate may be used instead of a resin film.

[0325] In the above method, in order to improve adhesion with adjacent layers or films, the above films or layers may be subjected to known treatments such as corona treatment or low-temperature plasma treatment as pretreatments before application of the composition.

[0326] From the viewpoint of the bendability and visibility of the display device, the thickness of the polarizing plate in the present invention is preferably 1 to 100 μm, more preferably 2 to 70 μm, and even more preferably 3 to 60 μm.

[0327] [Circular polarizing plate]

[0328] The present invention also takes a circular polarizing plate or an elliptical polarizing plate having the above-mentioned polarizing plate and a phase difference plate as an object. In one embodiment of the present invention, when a phase difference plate is stacked on the above-mentioned polarizing plate, it is preferred to stack the slow axis (optical axis) of the phase difference plate and the absorption axis of the polarizing plate in a manner substantially at 45°. By stacking the slow axis (optical axis) of the phase difference plate and the absorption axis of the polarizing plate in a manner substantially at 45°, a function as a circular polarizing plate can be obtained. In addition, the slow axis of the phase difference plate can be stacked in a manner substantially consistent with or orthogonal to the absorption axis of the polarizing plate. By making the slow axis of the phase difference plate substantially consistent with or orthogonal to the absorption axis of the polarizing plate, it can also function as an optical compensation film. It should be noted that substantially 45° generally refers to the range of 45±5°, and substantially consistent or orthogonal generally refers to the range of 0±5° or the range of 90±5°.

[0329] The circularly polarizing plate and the elliptically polarizing plate can be produced, for example, by a method including applying an adhesive to one surface of a polarizing plate and bonding the polarizing plate to a retardation plate via the adhesive.

[0330] The retardation plate in the present invention refers to an optical film exhibiting optical anisotropy, and is used to convert linearly polarized light into circularly polarized light or elliptically polarized light, or conversely, to convert circularly polarized light or elliptically polarized light into linearly polarized light.

[0331] The phase difference plate preferably satisfies the following formula (X).

[0332] Re(450nm) / Re(550nm)<1(X)

[0333] [Where Re(λ) represents the front retardation value for light with a wavelength of λnm]

[0334] If the phase difference plate satisfies the above formula (X), the phase difference plate has reverse wavelength dispersion, thereby reducing coloration when displaying black in a display device equipped with the phase difference plate. The value of Re (450 nm) / Re (550 nm) can be appropriately selected. The value of Re (450 nm) / Re (550 nm) is preferably 0.93 or less, more preferably 0.88 or less, and even more preferably 0.86 or less, and preferably 0.80 or more, and more preferably 0.82 or more.

[0335] As a phase difference plate, for example, there can be mentioned: a stretched film (phase difference film) obtained by stretching a polymer film formed by a polymer such as polyvinyl alcohol, polycarbonate, polyester, polyarylate, polymethacrylate, polyimide, polyolefin, polycycloolefin (polymer of norbornene, tetracyclododecene or their derivatives), polystyrene, polysulfone, polyethersulfone, polyvinylidene fluoride / polymethyl methacrylate, liquid crystal polyester, cellulose acetate, ethylene-vinyl acetate copolymer saponification, polyvinyl chloride to about 1.01 to 6 times. Among them, a polymer film obtained by uniaxially stretching or biaxially stretching a polycarbonate film or a polycycloolefin film is preferred. In one embodiment of the present invention, a polymer composition containing the above polymer is formed into a film, and the obtained film is uniaxially stretched or biaxially stretched to obtain a phase difference film.

[0336] In addition, a film (retardation film) that exhibits optical anisotropy by coating and orienting a liquid crystal compound can also be used as a phase difference plate. The phase difference film can be a single layer consisting solely of a cured layer of the liquid crystal compound, or it can be a two-layer structure consisting of a laminate of the cured layer and an orientation film. In the case where the phase difference film is a single layer, the circular polarizing plate or elliptically polarizing plate has a laminated structure of polarizing plate / retardation film. In the case where the phase difference film is composed of two layers, the circular polarizing plate or elliptically polarizing plate has a laminated structure of polarizing plate / retardation film / orientation film or polarizing plate / orientation film / retardation film.

[0337] From the perspective of thinning, the retardation film is preferably a cured layer of a polymerizable liquid crystal composition (hereinafter also referred to as the polymerizable liquid crystal composition (C)) containing a polymer of a polymerizable liquid crystal compound. In the retardation film, the polymerizable liquid crystal compound is typically polymerized in an oriented state. The polymerizable liquid crystal compound (hereinafter also referred to as the "polymerizable liquid crystal compound (C)") that forms the retardation film refers to a liquid crystal compound having a polymerizable functional group, particularly a photopolymerizable functional group. A photopolymerizable functional group refers to a group that can participate in a polymerization reaction via an active free radical or acid generated by a photopolymerization initiator. Examples of photopolymerizable functional groups include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloyloxy, methacryloyloxy, oxiranyl, and oxetane. Among these, acryloyloxy, methacryloyloxy, vinyloxy, oxiranyl, and oxetane are preferred, with acryloyloxy being more preferred. The liquid crystal properties may be thermotropic or lyotropic, and the phase-ordered structure may be nematic or smectic. As the polymerizable liquid crystal compound, only one type may be used or two or more types may be used in combination.

[0338] As a specific polymerizable liquid crystal compound (C), for example, the polymerizable liquid crystal compounds exemplified in Japanese Patent Application Laid-Open No. 2020-56834 can be used.

[0339] The polymerizable liquid crystal composition (C) may contain a polymerization initiator for initiating the polymerization reaction of the polymerizable liquid crystal compound (C). The polymerization initiator can be appropriately selected from polymerization initiators conventionally used in this field and may be a thermal polymerization initiator or a photopolymerization initiator. However, from the perspective of initiating the polymerization reaction at lower temperatures, a photopolymerization initiator is preferred. Preferred examples include the same photopolymerization initiators previously exemplified as photopolymerization initiators that can be used in the first resin layer-forming composition. Furthermore, the polymerizable liquid crystal composition (C) may contain additives such as those exemplified as additives that can be included in the first resin layer-forming composition or the polarizer-forming composition, as needed.

[0340] The polymerizable liquid crystal composition (C) is prepared, for example, by mixing and stirring the polymerizable liquid crystal compound (C) and, as needed, a polymerization initiator, additives, and the like. Furthermore, to improve coating properties, a solvent may be added to the polymerizable liquid crystal composition (C) to adjust the viscosity. Examples of the solvent include those exemplified above as solvents contained in the polarizer-forming composition.

[0341] A retardation film can be obtained by coating a polymerizable liquid crystal composition (C) onto a release film or an alignment film, removing the solvent by drying as needed, and then curing the polymerizable liquid crystal compound (C) in the resulting coating film by heating and / or using active energy rays. Examples of the alignment film include those previously exemplified as alignment films that can be used in the production of the polarizer of the present invention. When a release film is used, the film can be removed after curing the polymerizable liquid crystal compound (C) in the coating film, thereby obtaining a single-layer retardation film.

[0342] The coating method and curing conditions of the polymerizable liquid crystal composition (C) using active energy rays may be the same as those used in the method for producing the polarizing plate of the present invention.

[0343] The thickness of the phase difference plate can be appropriately selected depending on the display device to which it is applied, but is preferably 0.1 to 10 μm, more preferably 1 to 5 μm, and even more preferably 1 to 3 μm from the viewpoint of thin film thickness and flexibility.

[0344] [Display device]

[0345] The present invention also relates to a display device comprising the aforementioned polarizing plate, circular polarizing plate, or elliptically polarizing plate. The display device can be obtained by, for example, attaching the aforementioned polarizing plate, circular polarizing plate, or elliptically polarizing plate to the surface of the display device via an adhesive.

[0346] A display device refers to a device having a display element, which includes a light-emitting element or a light-emitting device as a light source. Examples of display devices include liquid crystal displays, electroluminescent (EL) displays, inorganic electroluminescent (EL) displays, touch panel displays, electron emission displays (e.g., field emission displays (FEDs) and surface field emission displays (SEDs)), electronic paper (displays using electronic ink or electrophoretic elements), plasma displays, projection displays (e.g., grating light valve (GLV) displays and displays using digital micromirror devices (DMDs)), and piezoelectric ceramic displays. Liquid crystal displays include transmissive, semi-transmissive, reflective, direct-view, and projection liquid crystal displays. These display devices can display two-dimensional images or three-dimensional images. In particular, the aforementioned polarizing plates, circular polarizing plates, and elliptical polarizing plates can be effectively used in liquid crystal displays and electroluminescent (EL) displays. A display device according to another embodiment of the present invention, which includes a polarizing plate having excellent polarization performance and durability, exhibits excellent image display capabilities and can more stably display these capabilities over time.

[0347] Example

[0348] The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Unless otherwise specified, "parts" and "%" in Examples and Comparative Examples are "parts by mass" and "% by mass."

[0349] [Preparation of evaluation samples]

[0350] The surface of the second resin layer of the polarizing plate produced in the examples and comparative examples was subjected to corona treatment and then laminated with an acrylic adhesive using a laminator. Next, the plate was cut into 40 mm x 40 mm pieces, and the adhesive surface was laminated to alkali-free glass to obtain a laminate consisting of norbornene-based resin film / first resin layer / polarizing film / photo-alignment film / second resin layer / acrylic adhesive / alkali-free glass. The laminate was heated at a temperature of 50°C and a pressure of 5 kg / cm 2 The samples were autoclaved at 490.3 kPa for 20 minutes and then left at 23°C and 55% relative humidity for 24 hours to prepare evaluation samples.

[0351] [Evaluation of Adhesion]

[0352] Evaluation of initial adhesion

[0353] A test was conducted to evaluate the initial adhesion of the polarizing plate by attaching a transparent tape to one corner of the norbornene-based resin film in the evaluation sample and then peeling it off. In the evaluation sample, the case where peeling was observed between the first resin layer and the polarizing film was designated "B", and the case where no peeling was observed between the first resin layer and the polarizing film was designated "A".

[0354] <Evaluation of Adhesion (After Storage at High Temperature and Humidity)>

[0355] The evaluation samples were stored at 80°C and 90% relative humidity for 65 hours. Next, a test was conducted in which a transparent tape was applied to one corner of the norbornene-based resin film in the evaluation sample and then peeled off to evaluate the adhesion of the polarizing plate (after storage at high temperature and high humidity). In the evaluation samples, if peeling was observed between the first resin layer and the polarizing film, the result was designated "B", and if no peeling was observed between the first resin layer and the polarizing film, the result was designated "A".

[0356] [Durability Evaluation]

[0357] The single-unit transmittance of the polarizing plates obtained in Examples and Comparative Examples was measured using the evaluation samples according to the following procedures.

[0358] Using a spectrophotometer (Shimadzu UV-3150) equipped with a holder equipped with a polarizing plate, the transmittance (Ta) along the transmission axis and the transmittance (Tb) along the absorption axis were measured using the double-beam method within the wavelength range of 380 nm to 780 nm. A grid that cuts off 50% of the light intensity was previously installed on the reference side of the holder. The single-element transmittance at each wavelength was calculated using the following formula. Furthermore, visual sensitivity correction was performed using the 2-degree field of view (illuminant C) according to JIS Z 8701, and the initial visual sensitivity-corrected single-element transmittance (Ty) was calculated.

[0359] Initial single-unit transmittance (%) = (Ta + Tb) / 2

[0360] <Change in Ty after high-temperature testing>

[0361] After the evaluation samples were stored at 105°C dry for 65 hours, the visual sensitivity-corrected single transmittance (Ty) after the high-temperature test was calculated in the same manner as the initial visual sensitivity-corrected single transmittance (Ty). The change in Ty after the high-temperature test, ΔTy1, was then calculated using the following formula.

[0362] ΔTy1 (%) = Ty after high temperature test - initial Ty

[0363] <Change in Ty after high temperature and high humidity test>

[0364] After the evaluation samples were stored at 80°C and 90% relative humidity for 65 hours, the visual sensitivity-corrected single transmittance (Ty) after the high-temperature, high-humidity test was calculated in the same manner as the initial visual sensitivity-corrected single transmittance (Ty). The change in Ty after the high-temperature, high-humidity test, ΔTy2, was then calculated using the following formula.

[0365] ΔTy2 (%) = Ty after high temperature and high humidity test - initial Ty

[0366] [Preparation of the Second Resin Layer and Polarizing Film]

[0367] <Preparation of Second Resin Layer-Forming Composition>

[0368] The following components were mixed and stirred at 50° C. for 4 hours to obtain a second resin layer-forming composition.

[0369] Multifunctional acrylate: 70 parts dipentaerythritol hexaacrylate

[0370] [Chemical Formula 16]

[0371]

[0372] Urethane acrylate:

[0373] EBECRYL 4858 (manufactured by DAICEL-ALLNEX Co., Ltd.) (number of functional groups: 2) 30 parts

[0374] Polymerization initiator:

[0375] Omnirad 907 (manufactured by IGM Resins BV) 3 parts

[0376] Solvent:

[0377] 10 parts of methyl ethyl ketone

[0378] <Preparation of a composition for forming a photo-alignment film>

[0379] A copolymer (1) having the following structure was prepared according to the following steps.

[0380] Copolymer (1):

[0381] [Chemical Formula 17]

[0382]

[0383] Chlorodimethyl ether was added dropwise to a solution of 4-((6-(methacryloyloxy)hexyl)oxy)benzoic acid and an amine catalyst dissolved in toluene. The reaction was then heated and maintained at 40°C. The reaction solution was then cooled to room temperature, and water was added. A 50% aqueous acetic acid solution was added to the separated organic layer, followed by stirring. The separated organic layer was concentrated to obtain methoxymethyl 4-((6-(methacryloyloxy)hexyl)oxy)benzoate.

[0384] 8.8 g (25.2 mmol) of methoxymethyl 4-((6-(methacryloyloxy)hexyl)oxy)benzoate, 1.0 g (3.6 mmol) of 6-(4-hydroxyphenoxy)hexyl methacrylate, 3.2 g (7.2 mmol) of 4-((6-(methacryloyloxy)hexyl)oxy)phenyl (E)-3-(4-methoxyphenyl)acrylate, and 0.2 g of 2,2'-azobis(2,4-dimethylvaleronitrile) were dissolved in tetrahydrofuran. Nitrogen was bubbled through the solution for 1 hour, and then the reaction was allowed to proceed by heating and maintaining it at 60°C. The reaction solution was then cooled to room temperature. 1.1 g (3.6 mmol) of 4-((6-(methacryloyloxy)hexyl)oxy)benzoic acid and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride were added to the reaction solution to obtain a mixed solution. The mixed solution was heated to 40°C to allow the reaction to proceed, and then the reaction solution was cooled to room temperature. Methanesulfonic acid was added to the reaction solution at room temperature, and after heating to 70°C, the reaction solution was cooled to near room temperature. The cooled reaction solution was added dropwise to n-hexane to form a precipitate, which was recovered and dried under reduced pressure to obtain a polymer (copolymer (1)). The weight average molecular weight of copolymer (1) was 24,000 as determined by GPC.

[0385] 4-((6-(methacryloyloxy)hexyl)oxy)phenyl(E)-3-(4-methoxyphenyl)acrylate and 4-((6-(methacryloyloxy)hexyl)oxy)benzoic acid used above were prepared according to the following procedures.

[0386] 4-((6-(methacryloyloxy)hexyl)oxy)phenyl (E)-3-(4-methoxyphenyl)acrylate

[0387] [Chemical Formula 18]

[0388]

[0389] 1,4-Dihydroxybenzene and 1,6-dibromohexane are heated under alkaline conditions to produce 6-(4-hydroxyphenoxy)-1-bromohexane. This product is reacted with lithium methacrylate to produce 6-(4-hydroxyphenoxy)hexyl methacrylate.

[0390] To the resulting product, p-methoxycinnamoyl chloride was added under alkaline conditions to prepare 4-((6-(methacryloyloxy)hexyl)oxy)phenyl (E)-3-(4-methoxyphenyl)acrylate.

[0391] 4-((6-(methacryloyloxy)hexyl)oxy)benzoic acid

[0392] [Chemical Formula 19]

[0393]

[0394] The preparation was carried out using methacryloyl chloride as a raw material using the method described in Makromol. Chem., 190, p2255-2268, 1989.

[0395] 2 parts of the obtained copolymer (1) and 98 parts of propylene glycol methyl ether acetate were mixed, and the mixture was stirred at 80° C. for 1 hour to obtain a composition for forming a photo-alignment film.

[0396] <Preparation of Polarizing Plate-Forming Composition>

[0397] The following components were mixed and stirred at 80°C for 1 hour to obtain a polarizing plate-forming composition. The non-coloring polymerizable liquid crystal compounds (X1) and (X2) had the structures shown below. Dichroic dyes (DP1) to (DP3) were prepared with reference to Japanese Patent Application Publication Nos. 2013-101328 and 7-224282.

[0398] Non-coloring polymerizable liquid crystal compound (X1): 75 parts

[0399] Non-coloring polymerizable liquid crystal compound (X2): 25 parts

[0400] Dichroic pigment (DP1): 2.8 parts

[0401] Dichroic pigment (DP2): 2.8 parts

[0402] Dichroic pigment (DP3): 2.8 parts

[0403] Polymerization initiator [2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure (registered trademark) 369; manufactured by BASF Japan Co., Ltd.]: 2 parts

[0404] Leveling agent [polyacrylate compound (BYK-361N; manufactured by BYK-Chemie)]: 1.2 parts

[0405] Solvent [o-xylene]: 250 parts

[0406] Non-coloring polymerizable liquid crystal compound (X1):

[0407] [Chemical Formula 20]

[0408]

[0409] Non-coloring polymerizable liquid crystal compound (X2):

[0410] [Chemical Formula 21]

[0411]

[0412] Dichroic pigment (DP1):

[0413] [Chemical Formula 22]

[0414]

[0415] ·Dichroic pigment (DP2):

[0416] [Chemical Formula 23]

[0417]

[0418] ·Dichroic pigment (DP3):

[0419] [Chemical Formula 24]

[0420]

[0421] <Preparation of the Second Resin Layer>

[0422] After corona treatment of the release-treated surface of a release-treated polyethylene terephthalate film (SP-PLR382050 manufactured by Lintec) (release film), the second resin layer-forming composition was applied using a bar coater (#2, 30 mm / s). The film was then heated and dried in a drying oven set at 80°C for 1 minute to form a dry film. Next, the dried film of the second resin layer-forming composition was irradiated with ultraviolet light (in a nitrogen atmosphere, cumulative light intensity at a wavelength of 365 nm: 500 mJ / cm) using a UV irradiation device (Unicure VB-15201BY-A, manufactured by Ushio Electric Co., Ltd.). 2 ), thereby obtaining a release film with a second resin layer formed on the surface of the release film. The thickness of the obtained second resin layer was measured using an ellipsometer M-220 (manufactured by JASCO Corporation) and found to be 1.5 μm.

[0423] Polarizing Film Production

[0424] Next, the surface of the second resin layer of the release film with the second resin layer was subjected to a corona treatment using a corona treatment device (AGF-B10; manufactured by Kasuga Electric Co., Ltd.) at an output of 0.3 kW and a treatment speed of 3 m / min. The photo-alignment film-forming composition was applied to the corona-treated surface of the second resin layer using a bar coater and dried at 80°C for 1 minute to obtain a dried film. Next, the dried film was subjected to a polarized UV irradiation device (SPOTCURE SP-9 with a polarizer unit; manufactured by USHIO Electric Co., Ltd.) at a rate of 50 mJ / cm 2 Polarized UV exposure was performed with the accumulated light intensity (in air atmosphere, the accumulated light intensity at a wavelength of 313 nm: 50 mJ / cm 2 ), a photo-alignment film was formed. The thickness of the photo-alignment film was measured using an ellipsometer M-220 (manufactured by JASCO Corporation) and found to be 100 nm.

[0425] Next, the polarizer-forming composition was applied to the photo-alignment film using a bar coater and then heated and dried in a drying oven set at 120°C for 1 minute to obtain a dry film. Next, the dry film of the polarizer-forming composition was irradiated with ultraviolet light (in a nitrogen atmosphere, cumulative light intensity at a wavelength of 365 nm: 500 mJ / cm) using a UV irradiation device (Unicure VB-15201BY-A, manufactured by USHIO Electric Co., Ltd.). 2 ), thereby forming a polarizing film in which the non-coloring polymerizable liquid crystal compound and the dichroic dye were oriented, resulting in a release-film-attached laminate film consisting of a release film / second resin layer / photo-alignment film / polarizing film. The thickness of the polarizing film, measured using an M-220 ellipsometer (manufactured by JASCO Corporation), was 2.0 μm.

[0426] Next, X-ray diffraction measurements of the polarizing film were performed using an X'Pert PRO MPD (manufactured by SPECTRIS Inc.). A sharp diffraction peak (Bragg peak) with a full width at half maximum (FWHM) of approximately 0.17° was observed near 2θ = 20.2°. The order period (d) determined from the peak position was approximately 4.4 Å, confirming the formation of a structure reflecting a high-order smectic phase.

[0427] <Preparation of the first resin layer forming composition (1)>

[0428] The following components were blended and mixed, and then degassed to prepare a first resin layer-forming composition (1).

[0429] (Free radical polymerizable compound)

[0430] Multifunctional acrylate (trade name: A-9550, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.): 56 parts by mass

[0431] 4-Hydroxybutyl acrylate (trade name: 4-HBA, manufactured by Osaka Organic Chemical Industry Co., Ltd.): 30 parts by mass

[0432] Urethane acrylate (trade name: Ziguang UV-7605B, Mitsubishi Chemical Corporation) (number of functional groups: 6): 14 parts by mass

[0433] (Photoradical polymerization initiator)

[0434] Radical polymerization initiator (trade name: Omnirad 819, manufactured by IGM Resins BV): 3.0 parts by mass

[0435] The viscosity of the first resin layer-forming composition (1) at 25° C. was measured in accordance with JIS K7367.

[0436] <Preparation of the first resin layer forming composition (2)>

[0437] A first resin layer-forming composition (2) was prepared in the same manner as the first resin layer-forming composition (1), except that the amounts of multifunctional acrylate (trade name: A-9550), 4-hydroxybutyl acrylate (trade name: 4-HBA), and urethane acrylate (trade name: Ziguang UV-7605B) were changed to 48 parts by mass, 40 parts by mass, and 12 parts by mass, respectively, and the viscosity thereof at 25°C was measured.

[0438] <Preparation of the first resin layer forming composition (3)>

[0439] A first resin layer-forming composition (3) was prepared in the same manner as the first resin layer-forming composition (1) except that the amounts of multifunctional acrylate (trade name: A-9550) and urethane acrylate (trade name: Ziguang UV-7605B) were changed to 40 parts by mass and 30 parts by mass, respectively, and its viscosity at 25°C was measured.

[0440] <Preparation of the first resin layer forming composition (4)>

[0441] A first resin layer-forming composition (4) was prepared in the same manner as the first resin layer-forming composition (1), except that the amounts of multifunctional acrylate (trade name: A-9550), 4-hydroxybutyl acrylate (trade name: 4-HBA), and urethane acrylate (trade name: Ziguang UV-7605B) were changed to 50 parts by mass, 42 parts by mass, and 8 parts by mass, respectively, and the viscosity thereof at 25°C was measured.

[0442] <Preparation of the first resin layer forming composition (5)>

[0443] A first resin layer-forming composition (5) was prepared in the same manner as the first resin layer-forming composition (1), except that the amounts of multifunctional acrylate (trade name: A-9550), 4-hydroxybutyl acrylate (trade name: 4-HBA), and urethane acrylate (trade name: Ziguang UV-7605B) were changed to 65 parts by mass, 25 parts by mass, and 10 parts by mass, respectively, and its viscosity at 25°C was measured.

[0444] <Preparation of the first resin layer forming composition (6)>

[0445] A first resin layer-forming composition (6) was prepared in the same manner as the first resin layer-forming composition (1) except that 56 parts by mass of a multifunctional acrylate (trade name: LIGHT ACRYLATE PE-3A, manufactured by Kyoeisha Chemical Co., Ltd.) was used instead of 56 parts by mass of the multifunctional acrylate (trade name: A-9550), and its viscosity at 25° C. was measured.

[0446] <Preparation of the first resin layer forming composition (7)>

[0447] The following components were blended and mixed, and then degassed to prepare a first resin layer-forming composition (7). The viscosity of the first resin layer-forming composition (7) at 25° C. was measured in accordance with JIS K7367.

[0448] (Free radical polymerizable compound)

[0449] Multifunctional acrylate (trade name: A-DPH, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.): 10 parts by mass

[0450] 4-Hydroxybutyl acrylate (trade name: 4-HBA, manufactured by Osaka Organic Chemical Industry Co., Ltd.): 80 parts by mass

[0451] Urethane acrylate (trade name: Ziguang UV-7650B, Mitsubishi Chemical Corporation) (number of functional groups: 5 or more): 10 parts by mass

[0452] (Photoradical polymerization initiator)

[0453] Radical polymerization initiator (trade name: Omnirad 819, manufactured by IGM Resins BV): 3.0 parts by mass

[0454] <Preparation of the first resin layer forming composition (8)>

[0455] A first resin layer-forming composition (8) was prepared in the same manner as the first resin layer-forming composition (1), except that 14 parts by mass of urethane acrylate (trade name: Ziguang UV-7605B) (number of functional groups: 2, weight-average molecular weight: 18,000) was used instead of 14 parts by mass of urethane acrylate (trade name: Ziguang UV-3000B, manufactured by Mitsubishi Chemical Corporation), and its viscosity at 25° C. was measured.

[0456] [Example 1]

[0457] The surface of a norbornene-based resin film [ZEONOR Film ZF-14, 23 μm, manufactured by ZEON Corporation of Japan] was treated once using a corona treatment apparatus (AGF-B10; manufactured by Kasuga Electric Co., Ltd.) at an output of 0.3 kW and a treatment speed of 3 m / min. Subsequently, a first resin layer-forming composition (1) was applied to the corona-treated surface using a bar coater to a thickness of 2.0 μm after UV curing.

[0458] The surface of the polarizing film of the laminated film with a release film produced by the above method was treated once using a corona treatment device (AGF-B10; manufactured by Kasuga Electric Co., Ltd.) at an output of 0.3 kW and a treatment speed of 3 m / min. Then, the surface subjected to the corona treatment was bonded to the surface of the composition (1) for forming the first resin layer, and then an ultraviolet irradiation device (manufactured by Fusion UV Systems Co., Ltd.) was used to irradiate the film at an accumulated light intensity of 600 mJ / cm 2 Under the conditions of UV-B, ultraviolet rays are irradiated from the side of the laminate film with the release film to cure the first resin layer-forming composition (1), thereby obtaining a laminate film with a release film consisting of norbornene-based resin film / first resin layer (1) / polarizing film / photo-alignment film / second resin layer / release film. The release film is peeled off from the obtained laminate film with the release film, thereby obtaining a polarizing plate (1) consisting of norbornene-based resin film / first resin layer (1) / polarizing film / photo-alignment film / second resin layer.

[0459] [Example 2]

[0460] A polarizing plate (2) consisting of a norbornene-based resin film / first resin layer (2) / polarizing film / photo-alignment film / second resin layer was manufactured using the same procedures as in Example 1, except that the first resin layer-forming composition (2) was used instead of the first resin layer-forming composition (1).

[0461] [Example 3]

[0462] A polarizing plate (3) consisting of a norbornene-based resin film / first resin layer (3) / polarizing film / photo-alignment film / second resin layer was manufactured using the same steps as in Example 1, except that the first resin layer-forming composition (3) was used instead of the first resin layer-forming composition (1).

[0463] [Example 4]

[0464] A polarizing plate (4) consisting of a norbornene-based resin film / first resin layer (4) / polarizing film / photo-alignment film / second resin layer was manufactured using the same steps as in Example 1, except that the first resin layer-forming composition (4) was used instead of the first resin layer-forming composition (1).

[0465] [Example 5]

[0466] A polarizing plate (5) consisting of a norbornene-based resin film / first resin layer (5) / polarizing film / photo-alignment film / second resin layer was manufactured using the same steps as in Example 1, except that the first resin layer-forming composition (5) was used instead of the first resin layer-forming composition (1).

[0467] [Example 6]

[0468] A polarizing plate (6) consisting of a norbornene-based resin film / first resin layer (6) / polarizing film / photo-alignment film / second resin layer was manufactured using the same steps as in Example 1, except that the first resin layer-forming composition (6) was used instead of the first resin layer-forming composition (1).

[0469] [Comparative Example 1]

[0470] A polarizing plate (7) consisting of a norbornene-based resin film / first resin layer (7) / polarizing film / photo-alignment film / second resin layer was manufactured using the same steps as in Example 1, except that the first resin layer-forming composition (7) was used instead of the first resin layer-forming composition (1).

[0471] [Comparative Example 2]

[0472] A polarizing plate (8) consisting of a norbornene-based resin film / first resin layer (8) / polarizing film / photo-alignment film / second resin layer was manufactured using the same steps as in Example 1, except that the first resin layer-forming composition (8) was used instead of the first resin layer-forming composition (1).

[0473] [Table 1]

[0474]

[0475] Description of Reference Numerals

[0476] 1 polarizer

[0477] 2 First resin layer

[0478] 3 Second resin layer

[0479] 10 Polarizing plate

Claims

1. A polarizing plate comprising a first resin layer and a polarizer adjacent to each other, The first resin layer is a cured product layer of a curable resin composition containing monofunctional (meth)acrylate, polyfunctional (meth)acrylate, and urethane acrylate. The number of functional groups of the urethane acrylate is 3 or more, The mass ratio of the polyfunctional (meth)acrylate to the monofunctional (meth)acrylate is 1 or more.

2. The polarizing plate according to claim 1, wherein The viscosity of the curable resin composition is 350 cps or less at 25°C.

3. The polarizing plate according to claim 1, wherein The content of the monofunctional (meth)acrylate in the curable resin composition is 20 parts by mass or more relative to 100 parts by mass of the total of the monofunctional (meth)acrylate, the polyfunctional (meth)acrylate, and the urethane acrylate.

4. The polarizing plate according to claim 1, wherein The mass ratio of the polyfunctional (meth)acrylate to the monofunctional (meth)acrylate is 2.6 or less.

5. The polarizing plate according to claim 1, wherein The monofunctional (meth)acrylate includes a monofunctional (meth)acrylate having a hydroxyl group. The polarizing plate according to claim 5 , wherein The monofunctional (meth)acrylate having a hydroxyl group is represented by the following formula (1): In the formula, n represents an integer from 1 to 12, A 1 represents O or NH, X 1 represents a methylene group optionally having a substituent, and when n is an integer of 2 or greater, at least one of the methylene groups may be substituted with an oxygen atom, and the substituents may be the same or different. 7 . The polarizing plate according to claim 1 , further comprising a second resin layer adjacent to the polarizer on the side opposite to the first resin layer. The polarizing plate according to claim 1 , further comprising a resin film on the side of the first resin layer opposite to the polarizer.

9. The polarizing plate according to claim 1, wherein The polarizing plate is a polarizing film containing a cured layer of a polymerizable liquid crystal composition containing a compound exhibiting dichroism and a polymerizable liquid crystal compound.

10. The polarizing plate according to claim 9, wherein The cured material layer contains 80% by mass or more of a polymerizable liquid crystal compound relative to the total mass of the cured material layer. The polymer of the polymerizable liquid crystal compound exhibits a smectic liquid crystal phase. The compound exhibiting dichroism and the polymer of the polymerizable liquid crystal compound are aligned and contained in the cured product layer.

11. The polarizing plate according to claim 9, wherein Compounds that exhibit dichroism are azo dyes. 12 . A circularly polarizing plate comprising the polarizing plate according to claim 1 and a phase difference plate.

13. The circular polarizing plate according to claim 12, wherein The phase difference plate satisfies the following formula (X): Re(450nm) / Re(550nm)<1(X) Where Re(λ) represents the front retardation value for light with a wavelength of λ nm. 14 . A display device comprising the polarizing plate according to claim 1 , or the circularly polarizing plate according to claim 12 or 13 .

Images