Optical film, polarizing plate, and image display device

Abstract

The present invention addresses the problem of providing an optical film in which the initial peeling force between an alignment layer and a layer that is in contact with the alignment layer on the reverse side from a light absorption anisotropic layer side is small and the increase in peeling force over time is suppressed. An optical film according to the present invention comprises: a support; a cured layer disposed on and in contact with the support; an alignment layer disposed on and in contact with the cured layer; and a light absorption anisotropic layer disposed on and in contact with the alignment layer in this order. The cured layer contains a cured product of a compound having a polymerizable group. The Knoop indentation hardness of the cured layer is 175 N / mm2 or more.

Description

Optical film, polarizing plate, image display device

[0001] The present invention relates to an optical film, a polarizing plate, and an image display device.

[0002] Conventionally, in image display devices such as liquid crystal displays (LCDs), linear polarizing plates and circular polarizing plates have been used to control optical rotation and birefringence in display. In addition, circular polarizing plates are also used in organic light emitting diodes (OLEDs) to prevent reflection of external light. As the above circular polarizing plate, a configuration combining a light absorption anisotropic layer and a retardation layer (optical anisotropic layer) has been studied. Such a configuration is also used as a part of components of a virtual reality display device.

[0003] As an optical element including the light absorption anisotropic layer as described above, for example, Patent Document 1 discloses an optical element having a light absorption anisotropic layer containing a liquid crystal compound and a dichroic substance, wherein any part of the optical element contains a dye having a maximum absorption wavelength in a range of 630 nm or more and 780 nm or less, the dichroic substance has a structure different from that of the dye, and contains a first dichroic substance having a maximum absorption wavelength in a range of 560 nm or more and 640 nm or less.

[0004] Japanese Unexamined Patent Publication No. 2021-196514

[0005] The present inventors studied a laminate including the light absorption anisotropic layer disclosed in the above document, and found that the peeling force between the substrate and the alignment layer in the laminate may increase over time, and there is a need for further improvement.

[0006] Accordingly, an object of the present invention is to provide an optical film in which the initial peeling force between the alignment layer and the layer in contact with the opposite side of the alignment layer from the light absorption anisotropic layer side is small, and the increase in peeling force over time is also suppressed. In the configuration of the optical film of the present invention, the layer in contact with the opposite side of the alignment layer from the light absorption anisotropic layer side is a cured layer described later. Another object of the present invention is to provide a polarizing plate and an image display device comprising the above optical film.

[0007] As a result of intensive studies to solve the above problems, the present inventors have found that the problems can be solved by the following constitution.

[0008] [1] An optical film comprising a support, a cured layer disposed in contact with the support, an alignment layer disposed in contact with the cured layer, and a light absorption anisotropic layer disposed in contact with the alignment layer in this order, wherein the cured layer contains a cured product of a compound having a polymerizable group, and the indentation Knoop hardness of the cured layer is 175 N / mm ２ or more. [2] The optical film according to [1], wherein the compound having a polymerizable group contains at least one compound selected from the group consisting of polyfunctional acrylates and polyfunctional methacrylates. [3] The optical film, wherein the number of polymerizable groups relative to the molecular weight of the compound having a polymerizable group is 50.0×10 －４The optical film according to [1] or [2], wherein the above conditions are met. [4] The optical film according to any one of [1] to [3], wherein the surface energy of the cured layer is 34.0 mN / m or more. [5] The optical film according to any one of [1] to [4], wherein the thickness of the cured layer is 0.5 to 3.5 μm. [6] The optical film according to any one of [1] to [5], wherein the light-absorbing anisotropic layer is a layer formed using a composition containing a dichroic substance and a liquid crystal compound, and the content of the dichroic substance is 10% by mass or more with respect to the total solid content of the composition. [7] The optical film according to any one of [1] to [6], wherein the orientation layer is a photo-orientation layer. [8] The optical film according to [7], wherein the photo-orientation layer is a layer formed using a composition containing a photo-orientation compound having polymerizable groups. [9] The optical film according to any one of [1] to [8], wherein the thickness of the orientation layer is 1.0 μm or less.

[10] An optical film according to any one of [1] to [9], wherein the smoothness of the surface of the orientation layer on the hardened layer side is 0.20 arcmin or less.

[11] An optical film according to any one of [1] to

[10] , wherein the total thickness of the hardened layer and the orientation layer is 1.0 μm or more.

[12] An optical film according to any one of [1] to

[11] , wherein the peeling force between the hardened layer and the orientation layer is 0.02 to 0.30 N / 25 mm.

[13] A polarizing plate comprising a laminate obtained by peeling the support and the hardened layer from the optical film according to any one of [1] to

[12] .

[14] An image display device comprising a laminate obtained by peeling the support and the hardened layer from the optical film according to any one of [1] to

[12] .

[15] An image display device having the polarizing plate according to

[13] .

[0009] According to the present invention, an optical film can be provided in which the initial peeling force between the orientation layer and the contact layer on the opposite side of the light-absorbing anisotropy layer of the orientation layer is small, and the increase in peeling force over time is also suppressed. Furthermore, according to the present invention, a polarizing plate and an image display device relating to the above optical film can also be provided.

[0010] This is a schematic diagram showing an example of the optical film of the present invention. This is a schematic diagram showing an example of the polarizing plate of the present invention.

[0011] The present invention will be described in detail below. The following descriptions of constituent elements may be based on typical embodiments of the present invention, but the present invention is not limited to such embodiments.

[0012] In this specification, a numerical range expressed using "~" means a range that includes the numbers before and after "~" as the lower and upper limits. Also, in this specification, if there are two or more types of a certain component, unless otherwise specified, the "content" of that component means the total content of those two or more types of components. In this specification, in numerical ranges described in steps, the upper or lower limit stated in one numerical range may be replaced with the upper or lower limit of another numerical range described in steps. Also, in numerical ranges described in this specification, the upper or lower limit stated in one numerical range may be replaced with the value shown in the example. In this specification, a combination of two or more preferred embodiments is a more preferred embodiment.

[0013] In this specification, "(meth)acrylic" is a concept that encompasses both acrylic and methacrylic, and "(meth)acrylate" is a concept that encompasses both acrylate and methacrylate. In this specification, solids refer to film-forming components and do not include solvents. Furthermore, any film-forming component is considered a solid, even if its properties are liquid. In this specification, "absorption axis" means the polarization direction in which the absorbance is maximum when linearly polarized light is incident on it. Also, "in-plane slow axis" means the direction in which the refractive index is maximum in the plane.

[0014] In this specification, Re(λ) and Rth(λ) represent the in-plane retardation and thickness retardation at wavelength λ, respectively. Unless otherwise specified, wavelength λ is 550 nm. Furthermore, in this specification, Re(λ) and Rth(λ) are values ​​measured at wavelength λ using AxoScan (manufactured by Axometrics). Specifically, by inputting the average refractive index ((nx + ny + nz) / 3) and film thickness (d) into AxoScan, the following can be calculated: In-plane retardation axis direction (°) Re(λ) = R0(λ) Rth(λ) = ((nx + ny) / 2 - nz) × d Note that R0(λ) is displayed as a numerical value calculated by AxoScan, but it means Re(λ).

[0015] In this specification, the refractive indices nx, ny, and nz are measured using an Abbe refractometer (NAR-4T, manufactured by Atago Corporation) with a sodium lamp (λ = 589 nm) as the light source. Wavelength dependence can be measured using a multi-wavelength Abbe refractometer DR-M2 (manufactured by Atago Corporation) in combination with an interference filter. Values ​​from the Polymer Handbook (JOHN WILEY & SONS, INC.) and catalogs of various optical films can also be used. Examples of average refractive index values ​​for major optical films are given below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).

[0016] In this specification, A plates and C plates are defined as follows: There are two types of A plates: positive A plates and negative A plates. When the refractive index in the in-plane slow axis direction (the direction in which the refractive index is maximum in the plane) of the film is nx, the refractive index in the direction perpendicular to the in-plane slow axis is ny, and the refractive index in the thickness direction is nz, a positive A plate satisfies the relationship in equation (A1), and a negative A plate satisfies the relationship in equation (A2). Note that a positive A plate has a positive Rth value, and a negative A plate has a negative Rth value. Equation (A1) nx > ny ≈ nz Equation (A2) ny < nx ≈ nz Note that the above "≈" includes not only cases where the two are completely identical, but also cases where the two are substantially identical. "Substantially identical" means, for example, that when (ny - nz) × d (where d is the film thickness) is -10 to 10 nm, preferably -5 to 5 nm, it is included in "ny ≈ nz", and when (nx - nz) × d is -10 to 10 nm, preferably -5 to 5 nm, it is included in "nx ≈ nz". There are two types of C plates: positive C plates and negative C plates. A positive C plate satisfies the relationship in equation (C1), and a negative C plate satisfies the relationship in equation (C2). Note that a positive C plate shows a negative Rth value, and a negative C plate shows a positive Rth value. Equation (C1) nz > nx ≈ ny Equation (C2) nz < nx ≈ ny Note that the above "≈" includes not only cases where the two are completely identical, but also cases where the two are substantially identical. "Substantially identical" means that, for example, when (nx - ny) × d (where d is the thickness of the film) is 0 to 10 nm, preferably 0 to 5 nm, it is included in "nx ≈ ny".

[0017] [Optical Film] The optical film of the present invention will be described in detail below. The optical film of the present invention comprises, in this order, a support, a cured layer disposed in contact with the support, an orientation layer disposed in contact with the cured layer, and a light-absorbing anisotropic layer disposed in contact with the orientation layer, wherein the cured layer contains a cured product of a compound having polymerizable groups, and the indentation Knoop hardness of the cured layer is 175 N / mm ２ That's all.

[0018] The reason why an optical film having the above configuration can solve the problems of the present invention is not necessarily clear, but the inventors speculate as follows. Note that the following speculation does not limit the mechanism by which the effect is obtained. In other words, even if the effect is obtained by a mechanism other than those described below, it is still within the scope of the present invention. The inventors have found that when a support and an orientation layer are arranged in contact, the peeling force between the support and the orientation layer increases over time due to the diffusion of components in the orientation layer into the support. The optical film of the present invention has a cured layer between the support and the orientation layer, which contains a cured compound having polymerizable groups and has a predetermined hardness. A cured layer with a hardness of a predetermined value or higher usually contains a crosslinking structure within the cured layer to achieve that hardness, and as a result, component movement within the cured layer is less likely to occur. Such a cured layer suppresses the diffusion of components from the orientation layer, and can suppress the increase in peeling force over time. Furthermore, according to the inventors' studies, the initial peeling force can be high depending on the hardness of the orientation layer and the adjacent layer, but in the optical film of the present invention, the initial peeling force is also small because the hardness of the cured layer is above a predetermined value. Hereinafter, the ability to achieve at least one of the following—that the initial peeling force between the hardened layer and the oriented layer is smaller, or that the increase in peeling force over time is more suppressed—is also referred to simply as "the effects of the present invention are superior."

[0019] Figure 1 shows a schematic cross-sectional view of the optical film of the present invention. As shown in Figure 1, the optical film 100 has a support 102, a cured layer 104, an orientation layer 106, and a light-absorbing anisotropy layer 108 in this order. As shown in Figure 1, in the optical film 100 of the present invention, the cured layer 104 is arranged in contact with the support 102, the orientation layer 106 is arranged in contact with the cured layer 104, and the light-absorbing anisotropy layer 108 is arranged in contact with the orientation layer 106. Each layer of the optical film of the present invention will be described in detail below.

[0020] [Support] The optical film of the present invention has a support. The type of support is not particularly limited, and known supports can be used, but a transparent support is preferred. A transparent support refers to a support with a visible light transmittance of 60% or more, preferably 80% or more, and more preferably 90% or more.

[0021] As the above-mentioned support, polymer films are preferred, for example. Examples of polymer film materials include cellulose polymers; acrylic polymers having acrylic acid ester polymers such as polymethyl methacrylate and lactone ring-containing polymers; thermoplastic norbornene polymers; polycarbonate polymers; polyester polymers such as polyethylene terephthalate (PET) and polyethylene naphthalate; styrene polymers such as polystyrene and acrylonitrile-styrene copolymer (AS resin); polyolefin polymers such as polyethylene, polypropylene, and ethylene-propylene copolymer; vinyl chloride polymers; amide polymers such as nylon and aromatic polyamides; imide polymers; sulfone polymers; polyethersulfone polymers; polyetheretherketone polymers; polyphenylene sulfide polymers; vinylidene chloride polymers; vinyl alcohol polymers; vinyl butyral polymers; arylate polymers; polyoxymethylene polymers; epoxy polymers; and polymers obtained by mixing these polymers.

[0022] The above-mentioned support preferably has a small phase difference. Specifically, the in-plane retardation at a wavelength of 550 nm is preferably 10 nm or less, and the absolute value of the retardation in the thickness direction at a wavelength of 550 nm is preferably 50 nm or less.

[0023] The thickness of the support is not particularly limited, but is preferably 5 to 300 μm, and more preferably 5 to 100 μm.

[0024] [Cured Layer] The optical film of the present invention has a cured layer. The cured layer includes a cured product of a compound having polymerizable groups (hereinafter also referred to as "polymerizable compound"). The cured product of the polymerizable compound is obtained by curing the polymerizable compound. Details of the polymerizable compound will be described in detail in the cured layer forming composition described later.

[0025] The cured polymerizable compound may be used alone or in combination of two or more. The content of the cured polymerizable compound is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, based on the total mass of the cured layer. There is no particular upper limit, and it may be 100% by mass. That is, the cured layer may be a layer made of cured polymerizable compounds.

[0026] The cured layer may contain components other than the cured product of polymerizable compounds. Examples of other components include the components that may be included in the cured layer-forming composition described later, and components derived therefrom.

[0027] <Method for forming the cured layer> The method for forming the cured layer is not particularly limited, but it is preferable to form it using a cured layer-forming composition containing a polymerizable compound. For example, a preferred method is to apply the cured layer-forming composition onto a support to form a coating film and then cure the coating film.

[0028] Examples of the coating methods mentioned above include known methods such as roll coating, gravure printing, spin coating, wire bar coating, extrusion coating, direct gravure coating, reverse gravure coating, die coating, spray coating, and inkjet coating.

[0029] The above curing treatment is carried out, for example, by heating and / or light irradiation (exposure), with light irradiation being preferred. Various light sources can be used for the light irradiation, such as infrared light, visible light, and ultraviolet light, but ultraviolet light is preferred. Furthermore, ultraviolet light may be irradiated while heating during curing, or ultraviolet light may be irradiated through a filter that transmits only specific wavelengths. In addition, exposure may be carried out under an inert atmosphere such as nitrogen.

[0030] (Composition for forming a hardened layer) The composition for forming a hardened layer is not particularly limited as long as it can form a hardened layer, but it is preferable that it contains a polymerizable compound.

[0031] • Polymerizable Compounds The polymerizable groups of polymerizable compounds are not particularly limited, but radical polymerizable groups or cationic polymerizable groups are preferred. As radical polymerizable groups, generally known radical polymerizable groups can be used, and preferred examples include acryloyl groups or methacryloyl groups. In this case, the polymerization rate is generally known to be faster with acryloyl groups, and acryloyl groups are preferred from the viewpoint of improving productivity, but methacryloyl groups can also be used as polymerizable groups in the same way. As cationic polymerizable groups, generally known cationic polymerizable groups can be used, and specifically, examples include alicyclic ether groups, cyclic acetal groups, cyclic lactone groups, cyclic thioether groups, spiroorthoester groups, and vinyloxy groups. Among these, alicyclic ether groups or vinyloxy groups are preferred, and epoxy groups, oxetanyl groups, or vinyloxy groups are preferred. Among these, acryloyl groups or methacryloyl groups are preferred as polymerizable groups. That is, it is preferable that polymerizable compounds contain at least one compound selected from the group consisting of acrylates and methacrylates.

[0032] The number of polymerizable groups contained in the polymerizable compound is 1 or more, and 2 or more is preferable, and 3 or more is more preferable from the viewpoint of more excellent effects of the present invention. That is, the polymerizable compound is preferably a polyfunctional polymerizable compound, and more preferably a polyfunctional polymerizable compound having 3 or more functional groups. The upper limit of the number of polymerizable groups contained in the polymerizable compound is not particularly limited, but 8 or less is preferable, and 6 or less is more preferable. Among these, it is more preferable that the polymerizable compound contains at least one selected from the group consisting of polyfunctional acrylates and polyfunctional methacrylates (hereinafter, also referred to as "polyfunctional (meth)acrylate").

[0033] The molecular weight of the polymerizable compound is preferably 100 to 1000, more preferably 200 to 900, and still more preferably 250 to 800 from the viewpoint of more excellent effects of the present invention.

[0034] The ratio of the number of polymerizable groups to the molecular weight of the polymerizable compound (= number of polymerizable groups / molecular weight) is 50×10 －４ or more is preferable, and 80×10 －４ or more is more preferable, and 100×10 －４ or more is even more preferable. The upper limit of the ratio of the number of polymerizable groups to molecular weight is not particularly limited, but 200×10 －４ or less is preferable, and 180×10 －４ or less is more preferable, and 150×10 －４ or less is even more preferable. From the viewpoints that it is easy to adjust the hardness of the cured layer to a desired range and the effects of the present invention are more excellent, the content of the polymerizable compound in which the ratio of the number of polymerizable groups to molecular weight satisfies the above preferred range is preferably more than 70% by mass, more preferably 80% by mass or more, and still more preferably 90% by mass or more, based on the total mass of the polymerizable compound. The upper limit is not particularly limited, and may be 100% by mass. That is, the cured product of the polymerizable compound contained in the cured layer is preferably a cured product of a polymerizable compound in which the ratio of the number of polymerizable groups to molecular weight satisfies the above preferred range.

[0035] The polymerizable compound may be trifunctional or more functional, or may contain a ring structure, in terms of achieving superior effects according to the present invention. The ring may be an aromatic ring or an aliphatic ring, and may be a hydrocarbon ring or a heterocycle. Furthermore, the ring may be a monocyclic or polycyclic ring.

[0036] As polymerizable compounds, compounds represented by formula (1) or formula (2) are preferred, and compounds represented by formula (1) are more preferred. Formula (1) M １ - (P １ ) ｎ Formula (2) P ２ -L １ -P ３

[0037] In formula (1), P １ Each of these independently represents a polymerizable group. The polymerizable groups are as described above, with acryloyl or methacryloyl groups being preferred. n represents an integer of 3 or more, preferably an integer between 3 and 8, and more preferably an integer between 3 and 6. M １ The symbol represents an n-valent linking group. Examples of the above n-valent linking group include an n-valent hydrocarbon group which may have a group selected from -CO- and -O-. The number of carbon atoms in the above n-valent linking group is preferably 1 to 30, more preferably 2 to 20, and even more preferably 2 to 15. The above n-valent linking group may be in the form of a chain or may contain a ring.

[0038] In formula (2), P ２ and P ３ Each of these independently represents a polymerizable group. The polymerizable groups are as described above, with acryloyl or methacryloyl groups being preferred. １represents a divalent linking group. Examples of the above divalent linking group include a divalent hydrocarbon group which may have a group selected from -CO- and -O-. The number of carbon atoms in the above divalent linking group is preferably 1 to 30, and more preferably 2 to 20. The above divalent linking group may be linear or may contain a ring, and it is preferable that it contains a divalent ring group in terms of superior effects of the present invention. The above ring group may be either an aromatic ring group or an aliphatic ring group, and may be either a hydrocarbon ring group or a heterocyclic group. Furthermore, the above ring group may be either monocyclic or polycyclic. Furthermore, it is preferable that the above divalent linking group does not contain a polyalkylene oxy structure in terms of superior effects of the present invention. As for the above divalent linking group, a divalent hydrocarbon group which may contain a ring is preferred, and a linear or branched alkylene group having 1 to 6 carbon atoms, a divalent ring group, or a group formed by a combination thereof is more preferred.

[0039] The polymerizable compound may be used alone or in combination of two or more. The polymerizable compound content is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, based on the total solid content of the hardened layer-forming composition. There is no particular upper limit, and it may be 100% by mass, 99.9% by mass or less, or 99% by mass or less.

[0040] The composition for forming the cured layer may contain components other than polymerizable compounds. Examples of other components include polymerization initiators, solvents, and surfactants.

[0041] • Polymerization initiators are not particularly limited, but photopolymerization initiators are preferred. Photopolymerization initiators are not particularly limited, and examples include α-carbonyl compounds (US Patent Nos. 2,367,661 and 2,367,670), acyloin ethers (US Patent No. 2,448,828), α-hydrocarbon-substituted aromatic acyloin compounds (US Patent No. 2,722,512), polynuclear quinone compounds (US Patent Nos. 3,046,127 and 2,951,758), and combinations of triarylimidazole dimers and p-aminophenyl ketones (US Patent No. 3,549,36 Examples include those described in Japanese Patent Publication No. 7), acridine and phenazine compounds (Japanese Patent Publication No. 60-105667 and U.S. Patent No. 4,239850), oxadiazole compounds (U.S. Patent No. 4,212970), o-acyloxime compounds (Japanese Patent Publication No. 2016-027384

[0065] ), and acylphosphine oxide compounds (Japanese Patent Publication No. 63-040799, Japanese Patent Publication No. 5-029234, Japanese Patent Publication No. 10-095788 and Japanese Patent Publication No. 10-029997). Commercially available photopolymerization initiators can also be used, including BASF's Irgacure 184, Irgacure 907, Irgacure 369, Irgacure 651, Irgacure 819, Irgacure OXE-01, and Irgacure OXE-02.

[0042] Polymerization initiators may be used alone or in combination of two or more. When the hardened layer-forming composition contains a polymerization initiator, the content of the polymerization initiator is preferably 0.01 to 30% by mass, and more preferably 0.1 to 15% by mass, relative to the total solid content of the hardened layer-forming composition.

[0043] • Compositions for forming a solvent-cured layer preferably contain a solvent from the viewpoint of film formation. Examples of solvents include organic solvents such as ketones, ethers, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, halogenated carbons, esters, alcohols, cellosolves, cellosolve acetates, sulfoxides, amides, and heterocyclic compounds, as well as water.

[0044] The solvent may be used alone or in combination of two or more. When the hardened layer-forming composition contains a solvent, the solvent content is preferably 70 to 99% by mass, more preferably 83 to 97% by mass, and even more preferably 85 to 95% by mass, based on the total mass of the hardened layer-forming composition.

[0045] <Properties of the hardened layer> The indentation hardness of the hardened layer is 175 N / mm². ２ Therefore, the present invention offers superior effects, and the load capacity is 190 N / mm ２ The above is preferable, and 200 N / mm ２ The above is preferable. There is no particular upper limit to the indentation hardness, but 300 N / mm is preferable. ２ In many cases, the following occurs: 260 N / mm ２ The following is preferable. The indentation Knoop hardness of the hardened layer can be measured by the following method. Prepare a sample with the hardened layer exposed. Using a Fischerscope H100Vp hardness tester manufactured by Fischer Instruments, measure the hardness of the hardened layer surface of the sample fixed to a glass substrate using a Knoop indenter under the conditions of a loading time of 10 sec, a creep time of 5 sec, an unloading time of 10 sec, and a maximum load of 50 mN. Calculate the Knoop hardness from the relationship between the contact area between the indenter and the sample, determined from the indentation depth, and the maximum load. Perform this measurement at five points, and the average value is taken as the indentation Knoop hardness of the hardened layer. The measurement temperature is 23°C. As a method for adjusting the indentation Knoop hardness of the hardened layer, one method is to adjust the composition of the hardened layer.

[0046] The surface energy of the cured layer is preferably 34.0 mN / m or higher, more preferably 40.0 mN / m or higher, and even more preferably 45.0 mN / m or higher, in terms of the ability to form an orientation layer. There is no particular upper limit to the surface energy of the cured layer, but in terms of suppressing adhesion in the roll form of the laminate having the support and the cured layer, it is preferably 80.0 mN / m or lower, more preferably 75.0 mN / m or lower, and even more preferably 70.0 mN / m or lower. In terms of the ability to form an orientation layer and the adhesion described above, it is preferable that the surface energy on the orientation layer side of the cured layer satisfies the above range. The surface energy of the cured layer can be measured by the method shown in the later examples. A method for adjusting the surface energy of the cured layer is to adjust the composition of the cured layer.

[0047] The thickness of the cured layer is preferably 0.5 μm or more, more preferably 1.0 μm or more, and even more preferably 2.0 μm or more, in terms of superior smoothness of the orientation layer and the light absorption anisotropy layer. Furthermore, the thickness of the cured layer is preferably 5.0 μm or less, more preferably 3.5 μm or less, even more preferably 2.0 μm or less, and particularly preferably 1.0 μm or less, in terms of the transportability of the optical film. When the thickness of the cured layer is below the above upper limit, the effect of shrinkage associated with the formation of the cured layer is reduced, which is preferable in that curling of the optical film can be suppressed and the transportability of the optical film is superior. Furthermore, the thickness of the cured layer is also preferably 0.5 to 3.5 μm, more preferably 0.5 to 2.0 μm, and even more preferably 1.0 to 2.0 μm.

[0048] [Orientation Layer] The optical film of the present invention includes an orientation layer. The orientation layer is not particularly limited as long as it is a layer that can bring the light-absorbing anisotropy layer, described later, into a desired orientation state. Known orientation layers such as a so-called photo-orientation layer, which is formed by irradiating a photo-orientation compound with polarized or unpolarized light, and an orientation layer that has undergone rubbing treatment can be used as the orientation layer. Among these, the photo-orientation layer is preferred because it provides superior orientation of the light-absorbing anisotropy layer that is placed in contact with the orientation layer.

[0049] As the polymer material used for the orientation layer formed by the rubbing process, known materials can be used, with polyvinyl alcohol or polyimide and its derivatives being preferred. For the orientation layer subjected to the rubbing process, refer to the description on pages 43, line 24 to 49, line 8 of International Publication No. 2001 / 088574A1.

[0050] The photo-alignment layer preferably contains a photo-alignment compound. Furthermore, the photo-alignment layer is preferably a layer formed using a photo-alignment layer-forming composition containing a photo-alignment compound. The photo-alignment layer may also contain a cured product of a photo-alignment compound having polymerizable groups, as described later in the photo-alignment layer-forming composition.

[0051] <Method for forming the orientation layer> The method for forming the orientation layer is not particularly limited, but it is preferable to form it using an orientation layer forming composition. For example, one method is to form a film on a cured layer using an orientation layer forming composition and then apply an orientation treatment to the obtained film. As a method for forming a film on a cured layer using an orientation layer forming composition, one method is to apply the orientation layer forming composition to the cured layer to form a coating film and dry it as necessary. As the above application method, the method described above in the method for forming the cured layer can be used.

[0052] Examples of the orientation treatments mentioned above include polarized or unpolarized irradiation and rubbing treatment. The photo-oriented layer can be formed, for example, by oriented a film formed on a cured layer using a photo-oriented layer forming composition containing a photo-oriented compound by applying linearly polarized or unpolarized irradiation. The wavelength of light used for the orientation treatment varies depending on the photo-oriented compound and is not particularly limited as long as it is the wavelength necessary for the photoreaction. The peak wavelength of the light used for irradiation is preferably 200 to 700 nm, and ultraviolet light with a peak wavelength of 400 nm or less is more preferred.

[0053] Light sources used for light irradiation include commonly used light sources such as tungsten lamps, halogen lamps, xenon lamps, xenon flash lamps, mercury lamps, mercury xenon lamps, and carbon arc lamps; various lasers [e.g., semiconductor lasers, helium-neon lasers, argon ion lasers, helium-cadmium lasers, and YAG (yttrium-aluminum-garnet) lasers]; light-emitting diodes; and cathode ray tubes.

[0054] As means of obtaining linearly polarized light, methods using polarizers (e.g., iodine polarizers, two-color dye polarizers, and wire grid polarizers), methods using prism-type elements (e.g., Grant-Thomson prisms) or reflective polarizers utilizing the Brewster angle, or methods using light emitted from a polarized laser light source can be employed. Alternatively, filters or wavelength conversion elements may be used to selectively irradiate only the light of the required wavelength.

[0055] When linearly polarized light is used, the light is irradiated from the top or back of the film, and perpendicular or obliquely to the film surface. The angle of incidence of the light varies depending on the photo-oriented material, but is preferably 0 to 90° (perpendicular), and more preferably 40 to 90°. When unpolarized light is used, the film is irradiated with unpolarized light from an oblique angle. The angle of incidence is preferably 10 to 80°, more preferably 20 to 60°, and even more preferably 30 to 50°. The irradiation time is preferably 1 to 60 minutes, and more preferably 1 to 10 minutes.

[0056] If patterning is required, a method can be employed in which light irradiation using a photomask is performed the number of times necessary to create the pattern, or a method can be employed in which the pattern is written by laser scanning.

[0057] (Composition for forming a photo-alignment layer) The composition for forming a photo-alignment layer is not particularly limited as long as it can form a photo-alignment layer, but it is preferable that it contains a photo-alignment compound.

[0058] • Photo-orienting compounds: Photo-orienting compounds are preferably compounds having photo-orienting groups. A photo-orienting group is a group that has a photo-orienting function in which rearrangement or anisotropic chemical reaction is induced by irradiation with anisotropic light (e.g., plane-polarized light). Photo-orienting groups that undergo at least one of dimerization and isomerization upon the action of light are preferred because they have excellent orientation uniformity and good thermal and chemical stability.

[0059] Examples of photo-directing groups that dimerize upon the action of light include groups having the skeleton of at least one derivative selected from the group consisting of cinnamic acid derivatives, coumarin derivatives, chalcone derivatives, maleimide derivatives, and benzophenone derivatives. Examples of photo-directing groups that isomerize upon the action of light include groups having the skeleton of at least one compound selected from the group consisting of azobenzene compounds, stilbene compounds, spiropyran compounds, cinnamic acid compounds, and hydrazono-β-ketoester compounds.

[0060] The photo-directing group is preferably a group having the skeleton of at least one derivative selected from the group consisting of cinnamic acid derivatives, coumarin derivatives, chalcone derivatives, and maleimide derivatives, or a group having the skeleton of at least one compound selected from the group consisting of azobenzene compounds, stilbene compounds, and spiropyran compounds, and more preferably a group having the skeleton of a cinnamic acid derivative skeleton or a coumarin derivative skeleton.

[0061] Furthermore, it is preferable that the photo-orienting compound has polymerizable groups. That is, the photo-orienting layer is preferably a layer formed using a photo-orienting layer-forming composition containing a photo-orienting compound having polymerizable groups. The polymerizable groups are preferably radical polymerizable groups or cationic polymerizable groups. The photo-orienting compound may also have both radical polymerizable groups and cationic polymerizable groups. Examples of polymerizable groups include the polymerizable groups in the polymerizable compounds described above. Preferred cationic polymerizable groups are epoxy groups, epoxycyclohexyl groups, or oxetanyl groups. Preferred radical polymerizable groups are acryloyl groups, methacryloyl groups, vinyl groups, styryl groups, or allyl groups.

[0062] The photo-orienting compound is also preferably a photo-orienting polymer having repeating units having photo-orienting groups. Known structures can be used as the main chain structure of the repeating units having photo-orienting groups. In particular, a skeleton selected from the group consisting of (meth)acrylic, styrene, siloxane, cycloolefin, methylpentene, amide, and aromatic ester systems is preferred as the main chain structure of the repeating units having photo-orienting groups, a skeleton selected from the group consisting of (meth)acrylic, siloxane, and cycloolefin systems is more preferred, and a (meth)acrylic skeleton is even more preferred.

[0063] The above photo-orienting polymer may further preferably have repeating units having polymerizable groups. Details of the polymerizable groups are as described above. As for the structure of the main chain of the repeating units having polymerizable groups, known structures can be cited, with a skeleton selected from the group consisting of (meth)acrylic, styrene, siloxane, cycloolefin, methylpentene, amide, and aromatic ester systems being preferred, a skeleton selected from the group consisting of (meth)acrylic, siloxane, and cycloolefin systems being more preferred, and a (meth)acrylic skeleton being even more preferred. In particular, the photo-orienting compound is preferably a polymer having repeating units having photo-orienting groups, repeating units having cationic polymerizable groups, and repeating units having radical polymerizable groups. Examples of photo-orienting polymers include the polymers described in paragraphs

[0022] to

[0050] of Japanese Patent Application Publication No. 2024-120938, and the contents of these are incorporated herein.

[0064] The photo-orientation compound may be used alone or in combination of two or more types. The content of the photo-orientation compound is preferably 5 to 95% by mass, and more preferably 20 to 70% by mass, based on the total solid content of the photo-orientation layer forming composition.

[0065] The photo-alignment layer forming composition may contain other components besides the photo-alignment compound. Examples of other components include polymerization initiators, crosslinking agents, solvents, crosslinking catalysts, stabilizers, surfactants, adhesion improvers, plasticizers, and leveling agents.

[0066] • Polymerization initiator The polymerization initiator is not particularly limited and may be either a photopolymerization initiator or a thermal polymerization initiator. It may also be either a radical polymerization initiator or a cationic polymerization initiator. Examples of photopolymerization initiators include those that may be included in the cured layer forming composition described above. Examples of cationic polymerization initiators include known acid generators. Examples of acid generators include onium salt compounds, trichloromethyl-s-triazines, sulfonium salts, iodonium salts, quaternary ammonium salts, diazomethane compounds, imidosulfonate compounds, and oximesulfonate compounds.

[0067] Polymerization initiators may be used alone or in combination of two or more. When the photo-alignment layer forming composition contains a polymerization initiator, the content of the polymerization initiator is preferably 0.01 to 30% by mass, and more preferably 0.1 to 15% by mass, based on the total solid content of the photo-alignment layer forming composition.

[0068] The crosslinking agent photo-orientation layer forming composition preferably contains a crosslinking agent. The crosslinking agent is a compound different from the photo-orientation compound described above, and typically includes polymerizable compounds that do not have photo-orientation groups. Examples of polymerizable groups in the crosslinking agent include the polymerizable groups in the polymerizable compounds described above. Furthermore, it is preferable that the crosslinking agent has two or more polymerizable groups. Examples of crosslinking agents include epoxy compounds, (meth)acrylic compounds, and oxetanyl compounds. In addition, polymerizable liquid crystal compounds or urethane acrylate monomers may be used as polymerizable compounds.

[0069] Examples of epoxy compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, brominated bisphenol A type epoxy compounds, bisphenol S type epoxy compounds, diphenyl ether type epoxy compounds, hydroquinone type epoxy compounds, naphthalene type epoxy compounds, biphenyl type epoxy compounds, fluorene type epoxy compounds, phenol novolac type epoxy compounds, orthocresol novolac type epoxy compounds, trishydroxyphenylmethane type epoxy compounds, trifunctional epoxy compounds, tetraphenyloleethane type epoxy compounds, dicyclopentadienephenol type epoxy compounds, hydrogenated bisphenol A type epoxy compounds, bisphenol A nucleated polyol type epoxy compounds, polypropylene glycol type epoxy compounds, glycidyl ester type epoxy compounds, glycidylamine type epoxy compounds, glyoxal type epoxy compounds, alicyclic epoxy compounds, and heterocyclic epoxy compounds.

[0070] Examples of (meth)acrylic compounds include (meth)acrylic acid diesters of alkylene glycols, (meth)acrylic acid diesters, (meth)acrylic acid diesters of polyhydric alcohols, (meth)acrylic acid diesters of ethylene oxide or propylene oxide adducts, epoxy (meth)acrylates, urethane (meth)acrylates, and polyester (meth)acrylates.

[0071] The crosslinking agent may be used alone or in combination of two or more types. When the photo-alignment layer forming composition contains a crosslinking agent, the crosslinking agent content is preferably 10 to 70% by mass, and more preferably 20 to 60% by mass, relative to the total solid content of the photo-alignment layer forming composition.

[0072] - The solvent photo-alignment layer forming composition preferably contains a solvent from the viewpoint of coating film formation. Examples of the solvent include solvents that may be contained in the curing layer forming composition described above, and organic solvents are preferred. The solvent may be used alone or two or more may be used in combination. When the photo-alignment layer forming composition contains a solvent, the solvent content is preferably 70 to 99% by mass, more preferably 83 to 97% by mass, and even more preferably 85 to 95% by mass, based on the total mass of the photo-alignment layer forming composition.

[0073] <Properties of the Orientation Layer> The smoothness of the surface of the orientation layer on the hardened layer side is preferably 0.20 arcmin or less, more preferably 0.15 arcmin or less, and even more preferably 0.10 arcmin or less. The lower limit of the smoothness of the surface of the orientation layer on the hardened layer side is not particularly limited, and is often 0.03 arcmin or more, and may be 0.05 arcmin or more. When the smoothness of the surface of the orientation layer on the hardened layer side is within the above range, distortion of the image displayed in an image display device by applying a polarizing plate, as described later, can be suppressed, which is preferable. The smoothness of the surface of the orientation layer on the hardened layer side is a value obtained by measuring the surface of the exposed orientation layer of a laminate (specific laminate, described later) obtained by removing (typically peeling off) the support and hardened layer from the optical film of the present invention. The smoothness can be measured from the reflected light when irradiation light is shone on the target surface, and specifically can be measured by the method described in the later examples. The above "arcmin" is twice the angle index "Slopemagnitude RMS" (corresponding to 2σ). One method for adjusting the surface smoothness of the hardened layer side of the orientation layer is to adjust the thickness of the orientation layer and the hardened layer.

[0074] The thickness of the orientation layer is not particularly limited as long as it can perform the orientation function, but it is preferably 1.5 μm or less, more preferably 1.0 μm or less, and even more preferably 0.5 μm or less. The lower limit of the thickness of the orientation layer is not particularly limited, but in terms of orientation function, it is preferably 0.05 μm or more, and more preferably 0.2 μm or more. In this optical film, since the above-described cured layer is formed, there is no need to impart a smoothness adjustment function to the orientation layer, and even if the thickness of the orientation layer is below the above upper limit, the smoothness of the light absorption anisotropy layer is excellent.

[0075] The total thickness of the orientation layer and the cured layer is preferably 10.0 μm or less, more preferably 8.0 μm or less, and even more preferably 6.0 μm or less, in terms of the formation of a light-absorbing anisotropic layer. The lower limit of the total thickness of the orientation layer and the cured layer is not particularly limited, but it is preferably 0.5 μm or more, more preferably 1.0 μm or more, and even more preferably 1.5 μm or more, in terms of covering the irregularities of the support and improving the smoothness of the light-absorbing anisotropic layer.

[0076] The peeling force between the orientation layer and the hardened layer is preferably 0.01 to 0.50 N / 25 mm, more preferably 0.02 to 0.30 N / 25 mm, and even more preferably 0.04 to 0.20 N / 25 mm. The above peeling force is the peeling force when the hardened layer is peeled from the orientation layer in a 180° direction at a speed of 5 m / min in a 25°C environment, and can be specifically measured by the method described in the examples below.

[0077] [Light Absorption Anisotropic Layer] The light absorption anisotropic layer can function as a linear polarizer, transmitting linearly polarized light in a certain direction and absorbing linearly polarized light in a direction perpendicular to this linearly polarized light.

[0078] The light-absorbing anisotropic layer preferably contains a dichroic substance, more preferably contains a dichroic substance and a liquid crystal compound, and even more preferably is a layer in which the orientation state of the liquid crystal compound and the dichroic substance is fixed. The orientation state of the liquid crystal compound is not particularly limited and may be horizontal, vertical, tilted, or twisted. Furthermore, the light-absorbing anisotropic layer is preferably a layer formed using a light-absorbing anisotropic layer-forming composition containing a dichroic substance and a liquid crystal compound.

[0079] <Method for forming a light-absorbing anisotropic layer> The method for forming the light-absorbing anisotropic layer is not particularly limited, but it is preferable to form it using a light-absorbing anisotropic layer-forming composition containing a dichroic substance and a liquid crystal compound. For example, a preferred method is to apply the light-absorbing anisotropic layer-forming composition onto an orientation layer to form a coating film, and then perform an orientation treatment to orient the dichroic substance and the liquid crystal compound. As the above coating method, the method described above in the method for forming the cured layer can be used.

[0080] The orientation treatment preferably includes a drying treatment. The drying treatment can remove components such as solvents from the coating film. The drying treatment may be carried out by leaving the coating film at room temperature for a predetermined time (for example, natural drying), or by heating and / or blowing air.

[0081] The orientation treatment may also preferably include a heat treatment. This further orients the dichroic substances contained in the coating film, resulting in a higher degree of orientation of the dichroic substances. The heating temperature is preferably 10 to 250°C, and more preferably 25 to 190°C, from the viewpoint of suitability for manufacturing. The heating time is preferably 1 to 300 seconds, and more preferably 1 to 60 seconds.

[0082] The orientation treatment may include a cooling treatment performed after the heat treatment. The cooling treatment is a process of cooling the heated coating film to room temperature (20-25°C). This further fixes the orientation of the dichroic substances contained in the coating film, and increases the degree of orientation of the dichroic substances. The cooling method is not particularly limited and can be carried out by known methods.

[0083] If at least one of the dichroic substance and the liquid crystal compound has polymerizable groups, a curing treatment may be performed after the orientation treatment. The curing process is carried out, for example, by heating and / or light irradiation (exposure), with light irradiation being preferred. Various light sources can be used for the light irradiation, such as infrared light, visible light, and ultraviolet light, but ultraviolet light is preferred. Furthermore, ultraviolet light may be irradiated while heating during curing, or ultraviolet light may be irradiated through a filter that transmits only specific wavelengths. In addition, exposure may be carried out under an inert atmosphere such as nitrogen.

[0084] (Composition for forming a light-absorbing anisotropic layer) The composition for forming a light-absorbing anisotropic layer is not particularly limited as long as it can form a light-absorbing anisotropic layer, but it is preferable that it contains a dichroic substance and a liquid crystal compound.

[0085] Dichroic substances: Dichroic substances refer to dyes whose absorbance differs depending on the direction. Dichroic substances may or may not exhibit liquid crystalline properties. The composition for forming a light-absorbing anisotropic layer may contain one type of dichroic substance or multiple types of dichroic substances. In particular, it is preferable to contain three or more types of dichroic substances, and more preferably four or more types of dichroic substances. There is no particular upper limit to the number of types of dichroic substances contained in the composition for forming a light-absorbing anisotropic layer, but six or fewer types are preferred.

[0086] Dichroic azo dye compounds are preferred as dichroic substances. Dichroic azo dye compounds refer to azo dye compounds whose absorbance differs depending on the direction. Dichroic azo dye compounds may or may not exhibit liquid crystalline properties. If dichroic azo dye compounds exhibit liquid crystalline properties, they may exhibit either nematic or smectic properties. The temperature range in which the liquid crystalline phase is exhibited is preferably room temperature (about 20 to 28°C) to 300°C, and more preferably 50 to 200°C from the viewpoint of handling and manufacturing suitability. The number of azo bonds contained in the dichroic azo dye compound may be one or more, more preferably two or more, and even more preferably two. That is, diazo dye compounds having two azo bonds are preferred as dichroic azo dye compounds.

[0087] In the present invention, from the viewpoint of color adjustment, it is preferable to use at least one dye compound having a maximum absorption wavelength in the range of 560 to 700 nm (hereinafter also referred to as the "first dichroic azo dye compound") and at least one dye compound having a maximum absorption wavelength in the range of 455 nm or more and less than 560 nm (hereinafter also referred to as the "second dichroic azo dye compound").

[0088] In the present invention, three or more dichroic azo dye compounds may be used in combination. For example, from the viewpoint of making the absorption polarizer closer to black, it is preferable to use a first dichroic azo dye compound, a second dichroic azo dye compound, and at least one dye compound having a maximum absorption wavelength in the range of 380 nm to less than 455 nm (hereinafter also abbreviated as "third dichroic azo dye compound"). In particular, it is preferable to use at least one first dichroic azo dye compound, at least one second dichroic azo dye compound, and at least one third dichroic azo dye compound, and to use a total of four or more first, second, and third dichroic azo dye compounds.

[0089] Examples of dichroic substances that can be used in the present invention include those described in International Publication No. 2018 / 186503, International Publication No. 2019 / 189345, and International Publication No. 2018 / 124198.

[0090] The dichroic substance may be used alone or in combination of two or more. The content of the dichroic substance is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and particularly preferably 15% by mass or more, relative to the total solid content of the light-absorbing anisotropic layer forming composition. There is no particular upper limit, but it is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less.

[0091] • Liquid crystal compounds: Both polymer liquid crystal compounds and low-molecular-weight liquid crystal compounds can be used as liquid crystal compounds, and polymer liquid crystal compounds are preferred because they allow for a high degree of orientation. Furthermore, polymer liquid crystal compounds and low-molecular-weight liquid crystal compounds may be used in combination. The liquid crystal compound may be immobilized in the light-absorbing anisotropic layer. Here, "polymer liquid crystal compound" refers to a liquid crystal compound having repeating units in its chemical structure. "Low-molecular-weight liquid crystal compound" refers to a liquid crystal compound that does not have repeating units in its chemical structure.

[0092] The low molecular weight liquid crystal compound is not particularly limited, but examples include compounds exhibiting a nematic liquid crystal phase and compounds exhibiting a smectic liquid crystal phase. Compounds exhibiting a smectic liquid crystal phase are preferred in terms of increasing the degree of orientation. For example, a liquid crystal compound described in Japanese Patent Application Publication No. 2013-228706 is an example.

[0093] Examples of polymeric liquid crystal compounds include the thermotropic liquid crystal polymer described in Japanese Patent Publication No. 2011-237513. When the light-absorbing anisotropic layer contains a polymeric liquid crystal compound, it is preferable that the polymeric liquid crystal compound forms a nematic liquid crystal phase. The temperature range in which the nematic liquid crystal phase is exhibited is preferably room temperature (23°C) to 450°C, and from the viewpoint of handling and manufacturing suitability, 50 to 400°C is preferred.

[0094] The liquid crystal compound may be used alone or in combination of two or more types. The content of the liquid crystal compound in the light-absorbing anisotropic layer-forming composition is preferably 25 to 2000 parts by mass, more preferably 100 to 1300 parts by mass, and even more preferably 200 to 900 parts by mass, per 100 parts by mass of the dichroic substance. Having the liquid crystal compound content within the above range is preferable because it further improves the degree of orientation of the dichroic substance.

[0095] Other components: The composition for forming the light-absorbing anisotropic layer may contain other components besides the dichroic substance and the liquid crystal compound. Examples of other components include adhesion improvers, surfactants, polymerization initiators, solvents, crosslinking agents, and plasticizers.

[0096] The light-absorbing anisotropic layer formation composition may contain an adhesion modifier. Examples of adhesion modifiers include reactive additives listed in paragraphs

[0123] to

[0129] of Japanese Patent Application Publication No. 2019-091088, and boronic acid monomers listed in paragraphs

[0015] to

[0028] of International Publication No. 2015 / 053359.

[0097] The adhesion improver may be used alone or in combination of two or more types. When the composition for forming a light-absorbing anisotropic layer contains an adhesion improver, the content of the adhesion improver is preferably 0.01 to 10% by mass, and more preferably 0.02 to 5% by mass, relative to the total solid content of the composition for forming a light-absorbing anisotropic layer.

[0098] The composition for forming a light-absorbing anisotropic layer may contain a surfactant. Examples of surfactants include fluorine (meth)acrylate polymers described in paragraphs

[0018] to

[0043] of Japanese Patent Application Publication No. 2007-272185, and silicon-containing polymers described in paragraphs

[0019] to

[0073] of International Publication No. 2023 / 054164. Other compounds may also be used as surfactants.

[0099] The surfactant may be used alone or in combination of two or more types. When the light-absorbing anisotropic layer-forming composition contains a surfactant, the surfactant content is preferably 0.01 to 10% by mass, and more preferably 0.02 to 5% by mass, relative to the total solid content of the light-absorbing anisotropic layer-forming composition.

[0100] The light-absorbing anisotropic layer-forming composition may contain a polymerization initiator. Examples of polymerization initiators include those that may be included in the cured layer-forming composition described above, with photopolymerization initiators being preferred. The polymerization initiator may be used alone or in combination of two or more. When the light-absorbing anisotropic layer-forming composition contains a polymerization initiator, the content of the polymerization initiator is preferably 0.01 to 30% by mass, and more preferably 0.1 to 15% by mass, relative to the total solid content of the light-absorbing anisotropic layer-forming composition.

[0101] The light-absorbing anisotropic layer-forming composition may contain a solvent. Examples of solvents include those that may be contained in the cured layer-forming composition described above, with organic solvents being preferred, and carbon halides or ketones being more preferred. The solvent may be used alone or in combination of two or more. When the light-absorbing anisotropic layer-forming composition contains a solvent, the solvent content is preferably 80 to 99% by mass, more preferably 83 to 99% by mass, and even more preferably 85 to 99% by mass, based on the total mass of the light-absorbing anisotropic layer-forming composition.

[0102] In the light-absorbing anisotropic layer, it is more preferable to orient the dichroic material by utilizing the orientation of the liquid crystal compound. In other words, by utilizing the technology of a guest-host liquid crystal cell, the dichroic material can be oriented to a desired orientation in conjunction with the orientation of the host liquid crystal. Specifically, a light-absorbing anisotropic layer can be fabricated by mixing a guest dichroic material with a liquid crystal compound that will act as the host liquid crystal, orienting the host liquid crystal, and then orienting the organic dichroic material along the orientation of its liquid crystal molecules, thereby fixing the orientation state.

[0103] <Properties of the light-absorbing anisotropic layer> The thickness of the light-absorbing anisotropic layer is not particularly limited, but is preferably 50.0 μm or less, more preferably 10.0 μm or less, and even more preferably 5.0 μm or less. The lower limit is not particularly limited, but is preferably 0.1 μm or more.

[0104] [Other Layers] The optical film of the present invention may have other layers besides those described above. Examples of other layers include an oxygen barrier layer. When the optical film of the present invention has other layers, it is preferable that they are arranged in contact with the side of the light absorption anisotropy layer opposite to the orientation layer. The oxygen barrier layer has the function of protecting the optical film from gases such as oxygen in the atmosphere, moisture, or compounds contained in adjacent layers. The oxygen permeability coefficient of the oxygen barrier layer is 200 cc / m³. ２ - Preferably, the temperature is 3 / day·atm or less, and the oxygen permeability coefficient is 50 cc / m³. ２ - A value of day·atm or less is more preferable. The oxygen permeability coefficient is an index that represents the amount of oxygen that passes through the membrane per unit time and per unit area. In the present invention, the value measured with an oxygen concentration device (for example, MODEL 3600 manufactured by Hack Ultra Analytical Corporation) under conditions of 25°C and 50% relative humidity (RH) is adopted.

[0105] The oxygen barrier layer is preferably transparent. In this invention, "transparent" means that the transmittance of visible light is 60% or more, preferably 80% or more, and more preferably 90% or more.

[0106] The oxygen barrier layer is not particularly limited, but for example, a layer containing 50% by mass or more of a resin is preferred. Examples of the resin include polyvinyl alcohol (PVA), modified polyvinyl alcohol, polyethylene vinyl alcohol, polyvinyl ether, polyvinylpyrrolidone, acrylic polymers (e.g., polyacrylamide, polyacrylic acid ester, etc.), cellulose ether, polyamide, polyimide, and styrene / maleic acid copolymer.

[0107] The thickness of the oxygen barrier layer is preferably 0.1 to 2.0 μm, more preferably 0.1 to 1.0 μm, and even more preferably 0.2 to 0.6 μm.

[0108] The method for manufacturing the optical film of the present invention is not particularly limited, and known methods can be employed. For example, a method for manufacturing the optical film of the present invention includes, in this order, the steps of forming a hardened layer on the surface of a support, forming an orientation layer on the surface of the obtained hardened layer, and forming a light-absorbing anisotropic layer on the surface of the obtained orientation layer. The method for manufacturing the optical film of the present invention may include steps other than those described above, for example, a step of further forming an oxygen barrier layer on the surface of the light-absorbing anisotropic layer. Details of the method for forming each layer are as described above.

[0109] [Polarizing Plate] The polarizing plate of the present invention includes a laminate (hereinafter also referred to as the "specific laminate") obtained by peeling off the support and hardened layer from the optical film of the present invention. The polarizing plate of the present invention may also include other layers besides the specific laminate. Examples of other layers include a phase difference layer, an adhesive layer, an anti-reflective layer, a protective layer, an ultraviolet absorption layer, and a blue light absorption layer. If the polarizing plate of the present invention has other layers, the other layers may be arranged on either the surface side of the orientation layer or the surface side of the light absorption anisotropy layer.

[0110] Figure 2 shows an example of a polarizing plate of the present invention. As shown in Figure 2, the polarizing plate 10B includes a specific laminate 12, an adhesive layer 14, and a phase difference layer 16. Depending on the type of phase difference layer 16, the polarizing plate 10B can be used as a so-called circular polarizing plate.

[0111] Furthermore, the specific laminate of the present invention may be used as a laminate comprising a specific laminate, an adhesive layer, a reflective polarizer, and a phase difference layer including a positive A plate and a positive C plate. Such a laminate is applicable as a component of a virtual reality display device.

[0112] The following describes in detail other layers that the polarizing plate of the present invention may contain.

[0113] [Phase Difference Layer] The polarizer of the present invention may include a phase difference layer. The type of phase difference layer is not particularly limited, but for example, the phase difference layer may include a λ / 4 plate. When the polarizer of the present invention includes a λ / 4 plate, the polarizer of the present invention can be used as a so-called circular polarizer. A λ / 4 plate is a plate having a λ / 4 function, and specifically, it is a plate that has the function of converting linearly polarized light of a certain wavelength (preferably visible light) to circularly polarized light (or circularly polarized light to linearly polarized light). The in-plane retardation of the λ / 4 plate at a wavelength of 550 nm is not particularly limited, but 120 to 150 nm is preferred, 125 to 145 nm is more preferred, and 135 to 140 nm is even more preferred. In addition to the λ / 4 plate, a phase difference layer in which the in-plane retardation at a wavelength of 550 nm is 3 / 4 or 5 / 4 of the wavelength of any light in the visible light spectrum is also preferred. The phase difference layer may have inverse wavelength dispersion properties. Having inverse wavelength dispersion means that the value of the phase difference at a given wavelength increases as the wavelength increases. The phase difference layer may be a single-layer or multi-layer structure. Specifically, an example of a multi-layer structure is a broadband λ / 4 plate formed by laminating a λ / 4 plate and a λ / 2 plate. The angle between the in-plane slow axis of the phase difference layer and the absorption axis of the optical absorption anisotropy layer is not particularly limited, but it is preferably within the range of 45° ± 10°.

[0114] The phase difference layer may be a layer in which a liquid crystal compound is immobilized that is twisted and oriented with the thickness direction as the helical axis. For example, as disclosed in Japanese Patent Publication No. 5753922 and Japanese Patent Publication No. 5960743, a phase difference layer may be a layer in which a rod-shaped or disc-shaped liquid crystal compound is immobilized that is twisted and oriented with the thickness direction as the helical axis.

[0115] The phase difference layer may include a positive A plate. The in-plane retardation of the positive A plate at wavelength 550 is not particularly limited, but is preferably 120 to 150 nm, more preferably 125 to 145 nm, and even more preferably 135 to 140 nm. The positive A plate preferably functions as the λ / 4 plate described above.

[0116] The phase difference layer may include a positive C plate. A positive C plate is a phase difference layer having substantially zero in-plane retardation and negative retardation in the thickness direction. The positive C plate functions as an optical compensation layer to increase the polarization degree of transmitted light for light incident at an oblique angle. The in-plane retardation of the positive C plate at a wavelength of 550 nm is preferably 10 nm or less. The retardation in the thickness direction of the positive C plate at a wavelength of 550 nm is preferably -600 to -40 nm.

[0117] The material constituting the phase difference layer is not particularly limited, but it is preferably formed from a composition containing a liquid crystal compound. Typically, such a phase difference layer can be obtained by vertically oriented rod-shaped polymerizable liquid crystal compounds contained in a polymerizable liquid crystal composition and fixing the orientation state by polymerization. Alternatively, it can also be formed from a composition containing a side-chain polymer liquid crystal compound as the liquid crystal compound.

[0118] The thickness of the phase difference layer is not particularly limited, but is preferably 0.1 to 8 μm, and more preferably 0.3 to 5 μm.

[0119] [Adhesive Layer] The polarizing plate of the present invention may have an adhesive layer. Examples of adhesives constituting the above adhesive layer include adhesives and adhesives. Examples of adhesives include rubber-based adhesives, acrylic-based adhesives, silicone-based adhesives, urethane-based adhesives, vinyl alkyl ether-based adhesives, polyvinyl alcohol-based adhesives, polyvinylpyrrolidone-based adhesives, polyacrylamide-based adhesives, and cellulose-based adhesives, with acrylic-based adhesives (pressure-sensitive adhesives) being preferred. Examples of adhesives include polyvinyl alcohol adhesives (water-based adhesives), solvent-type adhesives, emulsion-type adhesives, solvent-free adhesives, active energy ray-curing adhesives, and thermosetting adhesives. Examples of active energy ray-curing adhesives include electron beam-curing adhesives, ultraviolet-curing adhesives, and visible light-curing adhesives, with ultraviolet-curing adhesives being preferred.

[0120] The thickness of the adhesive layer is not particularly limited, but from the viewpoint of thinning, it is preferably 25 μm or less, more preferably 15 μm or less, and even more preferably 5 μm or less. The lower limit is not particularly limited, but it is often 0.1 μm or more.

[0121] The method for manufacturing the polarizing plate of the present invention is not particularly limited, and known methods can be used. If the polarizing plate of the present invention has other layers, the polarizing plate of the present invention may be obtained by laminating the above-mentioned specific laminate with the other layers, or the polarizing plate of the present invention may be obtained by laminating the optical film of the present invention with the other layers and then peeling off the support and cured layer.

[0122] [Image Display Device] The image display device of the present invention has the above-described specific laminate or the above-described polarizing plate. The image display device of the present invention is not particularly limited, but examples of image display devices include liquid crystal display devices, organic electroluminescent display devices, plasma display devices, micro-LED (Light Emitting Diode) display devices, head-up displays, and head-mounted displays. Furthermore, the above-described specific laminate and polarizing plate can also be suitably applied to virtual reality display devices.

[0123] The present invention will be described in more detail below based on examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the following examples can be modified as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the examples shown below.

[0124] [Example 1] The optical film of Example 1 was manufactured using the following procedure.

[0125] [Preparation of Support] The following composition was placed in a mixing tank, stirred, and then heated at 90°C for 10 minutes. The resulting composition was then filtered through filter paper with an average pore size of 34 μm and a sintered metal filter with an average pore size of 10 μm to prepare a dope. The solid content concentration of the dope was 23.5% by mass, the amount of plasticizer added was a ratio to the cellulose acylate, and the solvent of the dope was methylene chloride / methanol / butanol = 81 / 18 / 1 (by mass ratio).

[0126] -------------------------------------------------- Cellulose acylate dope -------------------------------------------------- Cellulose acylate (acetyl substitution degree 2.86, viscosity-average degree of polymerization 310) 100 parts by mass Sugar ester compound 1 (formula (S4) below) 6.0 parts by mass Sugar ester compound 2 (formula (S5) below) 2.0 parts by mass Silica particle dispersion (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) 0.1 parts by mass Solvent (methylene chloride / methanol / butanol) 351.9 parts by mass

[0127]

[0128]

[0129] The dope prepared as described above was cast using a drum film-forming machine. The dope was cast from the die so that it was in contact with a metal support cooled to 0°C, and then the resulting web (film) was peeled off the drum. The drum was made of SUS (stainless steel).

[0130] After the casting process, the obtained web (film) was peeled from the drum and dried for 20 minutes in a tenter device at 30-40°C during film transport, using clips to hold both ends of the web in place. Subsequently, the web was further dried by zone heating while being transported on a roll. The obtained web was knurled and then wound up to form cellulose acylate film A1. The thickness of the obtained cellulose acylate film A1 (TAC) was 60 μm, the in-plane retardation Re(550) at a wavelength of 550 nm was 1 nm, and the thickness-direction retardation Rth(550) at a wavelength of 550 nm was 35 nm.

[0131] [Formation of hardened layer G1] The hardened layer-forming composition G1 was continuously applied onto the cellulose acylate film A1 using a wire bar. The support with the formed coating was dried with 80°C hot air for 120 seconds, and then polarized ultraviolet light (300 mJ / cm²) was applied to the coating. ２ By using an ultra-high pressure mercury lamp, a cured layer G1 was formed, and a TAC film with a cured layer was obtained. The thickness of the cured layer G1 was 1.0 μm. -------------------------------------------------- Composition of composition G1 for cured layer formation -------------------------------------------------- ・Polyfunctional acrylate M-1 below 9.8 parts by mass ・Polymerization initiator IRGACUREOXE-02 (manufactured by BASF) 0.2 parts by mass ・Butyl acetate 90.0 parts by mass --------------------------------------------------

[0132] Polyfunctional acrylate M-1

[0133]

[0134] [Formation of Photo-Orientation Layer B1] The photo-orientation layer forming composition B1 was continuously applied onto the cured layer G1 using a wire bar. The support on which the coating film was formed was dried with 140°C hot air for 120 seconds, and then polarized ultraviolet light (10 mJ / cm²) was irradiated onto the coating film. ２By using an ultra-high pressure mercury lamp, a photo-alignment layer B1 was formed, and a photo-alignment layer-coated film A1G1B1 was obtained. The thickness of the photo-alignment layer B1 was 0.5 μm. -------------------------------------------------- Composition of photo-alignment layer-forming composition B1 -------------------------------------------------- ・The following polymer PA-1 (photo-alignment compound) 100.00 parts by mass ・EPICLON N-695 (manufactured by DIC Corporation) 53.57 parts by mass ・jER YX7400 (manufactured by Mitsubishi Chemical Corporation) 17.52 parts by mass ・Thermal cationic polymerization initiator PAG-1 15.65 parts by mass ・Stabilizer DIPEA 1.14 parts by mass ・Butyl acetate 827.68 parts by mass --------------------------------------------------

[0135] Polymer PA-1 (photo-oriented compound) (In the formula, the numerical values ​​listed for each repeating unit represent the content (mass%) of each repeating unit relative to the total number of repeating units.)

[0136]

[0137] Thermal cationic polymerization initiator PAG-1

[0138]

[0139] Stabilizer DIPEA

[0140]

[0141] [Formation of Light-Absorbing Anisotropic Layer C1] A light-absorbing anisotropic layer-forming composition C1 was applied to the obtained photo-alignment layer B1 using a wire bar to form a coating film. Next, the coating film was heated at 140°C for 15 seconds (first heating step), followed by heating at 80°C for 5 seconds, and then cooled to room temperature (25°C). Next, the coating film was heated at 75°C for 15 seconds (second heating step), and then cooled again to room temperature. After that, an illuminance of 200 mW / cm was applied using an LED lamp (center wavelength 365 nm). ２By irradiating under these conditions for 2 seconds, a 1.0 μm thick optical absorption anisotropy layer C1 (polarizer) was fabricated on the optical orientation layer B1. When the transmittance of the optical absorption anisotropy layer C1 in the wavelength range of 380 to 780 nm was measured using a spectrophotometer, the average visible light transmittance was 43%. The absorption axis of the optical absorption anisotropy layer C1 was located within the plane of the optical absorption anisotropy layer C1 and was perpendicular to the width direction of the cellulose acylate film A1.

[0142] -------------------------------------------------- Composition of Composition C1 for Light Absorption Anisotropic Layer Formation -------------------------------------------------- • Organic dichroic substance Dye-Y1 0.019 parts by mass • Organic dichroic substance Dye-M1 0.12 parts by mass • Organic dichroic substance Dye-C1 0.12 parts by mass • Organic dichroic substance Dye-C2 0.37 parts by mass • Liquid crystal compound L-1 1.29 parts by mass • Liquid crystal compound L-2 0.55 parts by mass • Adhesion improver A-1 0.04 parts by mass • Polymerization initiator IRGACUREOXE-02 (manufactured by BASF) 0.07 parts by mass • Surfactant F-3 0.006 parts by mass • Cyclopentanone 94.97 parts by mass • Benzyl alcohol 2.44 parts by mass --------------------------------------------------

[0143] Organic dichroic substance Dye-Y1

[0144]

[0145] Organic dichroic substance Dye-M1

[0146]

[0147] Organic dichroic substance Dye-C1

[0148]

[0149] Organic dichroic substance Dye-C2

[0150]

[0151] Liquid crystal compound L-1 (In the formula below, the numerical values ​​listed for each repeating unit represent the content (mass%) of each repeating unit relative to the total number of repeating units. Weight-average molecular weight: 18000)

[0152]

[0153] Liquid crystal compound L-2

[0154]

[0155] Adhesion improver A-1

[0156]

[0157] Surfactant F-3 (In the formula, the numerical values ​​listed for each repeating unit represent the content (mass%) of each repeating unit relative to the total number of repeating units. Weight-average molecular weight: 15000)

[0158]

[0159] [Formation of Oxygen Barrier Layer D1] An oxygen barrier layer-forming composition D1, having the following composition, was continuously applied to the light-absorbing anisotropic layer C1 using a wire bar. Subsequently, by drying with hot air at 80°C for 5 minutes, a laminate was obtained in which an oxygen barrier layer D1 made of polyvinyl alcohol (PVA) with a thickness of 0.4 μm was formed, namely, an optical film CP1 comprising a cellulose acylate film A1 (transparent support), a cured layer G1, a photo-alignment layer B1, a light-absorbing anisotropic layer C1, and an oxygen barrier layer D1 adjacent to each other in this order.

[0160] --------------------------------------------------------------------------- Composition of Composition D1 for Forming an Oxygen Barrier Layer --------------------------------------------------------------------------- Modified polyvinyl alcohol 2.39 parts by mass Initiator Irg2959 0.13 parts by mass Pyridinium p-toluenesulfonate 0.041 parts by mass 2,5-dimethoxy-2,5-dihydrofuran 0.13 parts by mass Surfactant S-1 0.0041 parts by mass (0.15% by mass relative to the total mass of solids) Surfactant S-2 0.0014 parts by mass (0.05% by mass relative to the total mass of solids) Water 74.70 parts by mass Ethanol 22.60 parts by mass ---------------------------------------------------------------------------

[0161] Modified polyvinyl alcohol

[0162]

[0163] Surfactant S-1: BYK3420, polyether-modified polydimethylsiloxane (manufactured by BIC Chemie Japan Co., Ltd.) Surfactant S-2: Rapizol® A-90, sodium di-2-ethylhexyl sulfosuccinate (manufactured by Nippon Oil & Fats Co., Ltd.)

[0164] [Examples 1-6 and Comparative Examples 3-4] An optical film was obtained by the same method as in Example 1, except that in the formation of the cured layer G1, the polyfunctional acrylate was changed to one of M-2 to M-5 shown in the table and the film thickness was changed to that shown in Table 1, and in the formation of the orientation layer B1, the film thickness was changed to that shown in Table 1, while the optical film comprising a cellulose acylate film A1 (transparent support), a cured layer G, a photo-orientation layer B1, a light-absorbing anisotropic layer C1, and an oxygen barrier layer D1 was arranged in this order adjacently. In Example 3, a PET film with a thickness of 100 μm (Cosmoshine A4265, manufactured by Toyobo Co., Ltd.) was used instead of the cellulose acylate film A1 (transparent support) as the support.

[0165] Polyfunctional acrylate M-2

[0166] Polyfunctional acrylate M-3

[0167] Polyfunctional acrylate M-4

[0168] Multifunctional acrylate M-5

[0169] [Comparative Example 1] Composition B1 for photo-alignment layer formation was continuously applied to the cellulose acylate film A1 using a wire bar. The support on which the coating film was formed was dried with hot air at 140°C for 120 seconds, and then polarized ultraviolet light (10 mJ / cm²) was irradiated onto the coating film. ２ By using an ultra-high pressure mercury lamp, a photo-alignment layer B1 was formed, and a cellulose acylate film with a photo-alignment layer was obtained. The thickness of the photo-alignment layer B1 was 1.5 μm.

[0170] Using the same method as in Example 1, a light-absorbing anisotropic layer C1 and an oxygen-blocking layer D1 were sequentially formed on the surface of the photo-alignment layer B1 of a cellulose acylate film with a photo-alignment layer, thereby obtaining an optical film comprising a cellulose acylate film A1 (transparent support), a photo-alignment layer B1, a light-absorbing anisotropic layer C1, and an oxygen-blocking layer D1 adjacent to each other in this order.

[0171] [Comparative Example 2] An optical film was obtained in the same manner as in Comparative Example 1, comprising a cellulose acylate film A1 (transparent support), a photo-alignment layer B2, a light-absorbing anisotropic layer C1, and an oxygen barrier layer D1 arranged in this order adjacently, except that in the formation of the photo-alignment layer, the photo-alignment layer forming composition B1 was changed to the photo-alignment layer forming composition B2 shown below. -------------------------------------------------- Composition of Composition B2 for Photo-Orientation Layer Formation -------------------------------------------------- • The above polymer PA-1 (photo-orientation compound) 100.00 parts by mass • EPICLON N-695 (manufactured by DIC Corporation) 53.57 parts by mass • jER YX7400 (manufactured by Mitsubishi Chemical Corporation) 17.52 parts by mass • Thermal cationic polymerization initiator PAG-1 15.65 parts by mass • Stabilizer DIPEA 1.14 parts by mass • Orthoxylene 827.68 parts by mass --------------------------------------------------

[0172] [Evaluation and Measurement] [Indentation Knoop Hardness] A laminate comprising a support, a hardened layer, an orientation layer, a light-absorbing anisotropy layer, and an oxygen-blocking layer was prepared using the same procedure as in the example. The orientation layer, the light-absorbing anisotropy layer, and the oxygen-blocking layer were peeled off to obtain a laminate having a support and a hardened layer. The support side of the obtained laminate was bonded to a glass substrate with an ultraviolet-curing adhesive to prepare a sample for measurement. Using a Fischerscope H100Vp hardness tester manufactured by Fischer Instruments Inc., the hardness of the hardened layer surface of the sample fixed to the glass substrate was measured under the conditions of a loading time of 10 sec, a creep time of 5 sec, an unloading time of 10 sec, and a maximum load of 50 mN, using a Knoop indenter with the orientation of the indenter's short axis parallel to the transport direction (longitudinal direction) of the optical film. The hardness was calculated from the relationship between the contact area between the indenter and the sample, which was determined from the indentation depth, and the maximum load. This measurement was performed on five points, and the average of these five points was defined as the indentation hardness. The measurement temperature was 23°C.

[0173] [Surface energy of the hardened layer] The surface energy of the hardened layer was measured by the following method. From a laminate comprising a support, a hardened layer, an orientation layer, a light-absorbing anisotropy layer, and an oxygen-blocking layer prepared using the same procedure as in the examples, the orientation layer, the light-absorbing anisotropy layer, and the oxygen-blocking layer were peeled off to prepare a sample for measurement consisting of the support and the hardened layer. Surface energy (γs ｖ : Dispersive force component (γs) in units of mN / m ｄ : Units, mN / m) and polar component (γs ｈ The unit (mN / m) is based on D. K. Owens: J. Appl. Polym. Sci., 13, 1741 (1969), measured on the surface of the hardened layer to be measured using pure water (H ２ O) and methylene iodide (CH ２ I ２ The contact angles of pure water and methylene iodide were determined experimentally using θ. Specifically, the contact angles of pure water and methylene iodide were determined to be θ. Ｈ２Ｏ and θ ＣＨ２Ｉ２ Therefore, by the following system of equations (SA) and (SB), γs ｄ and γs ｈ Find the value γs, which is the sum of these values. ｖ (=γs ｄ +γs ｈ The surface energy was defined as 1 + cosθ. The contact angle was measured after conditioned for more than 2 hours at a temperature of 20°C to 27°C and a relative humidity of 50°C to 65%, and then measured at a temperature of 25°C and a relative humidity of 60%. A contact angle meter (Dropmaster (manufactured by Kyowa Interface Science Co., Ltd.)) was used to measure the contact angle. Ｈ２Ｏ = 2√γs ｄ (√γ Ｈ２Ｏ ｄ / γ Ｈ２Ｏ ｖ ) + 2√γs ｈ (√γ Ｈ２Ｏ ｈ / γ Ｈ２Ｏ ｖ )...(SA) 1+cosθ ＣＨ２Ｉ２ = 2√γs ｄ (√γ ＣＨ２Ｉ２ ｄ / γ ＣＨ２Ｉ２ ｖ ) + 2√γs ｈ (√γ ＣＨ２Ｉ２ｈ / γ ＣＨ２Ｉ２ ｖ ) ... (SB) (However, γ Ｈ２Ｏ ｄ = 21.8, γ Ｈ２Ｏ ｈ = 51.0, γ Ｈ２Ｏ ｖ = 72.8, γ ＣＨ２Ｉ２ ｄ = 49.5, γ ＣＨ２Ｉ２ ｈ = 1.3, γ ＣＨ２Ｉ２ ｖ (= 50.8)

[0174] [Smoothness of the Orientation Layer] The smoothness of the orientation layer on the hardened layer side was measured using a phase-shift laser interferometer (Zygo, product name "DynaFiz"). Specifically, to prevent the inclusion of foreign matter, air bubbles, or deformation streaks, the oxygen barrier layer D1 side of the optical film was laminated to Eagle Glass XG (Corning) using Lintec Opteria D692 (thickness 5 μm) adhesive. Next, the support and hardened layer (or support if there is no hardened layer) were peeled off to expose the orientation layer and obtain the measurement sample. The measurement sample was placed on a measurement table with a vibration isolation table, and the relative displacement within a predetermined area (circle of 30 mm diameter) was measured by interfering it with a standard instrument with guaranteed flatness using a single-wavelength (wavelength 633 nm) laser. For the analysis, the angle index "Slopemagnitude RMS," obtained by extracting frequency values ​​from 0.1 / mm to 1 / mm, was doubled (corresponding to 2σ) and defined as surface smoothness (unit: arcmin).

[0175] [Peel Force (Initial)] The obtained optical film was cut to 150 mm x 25 mm, and the side of the optical film facing the oxygen barrier layer D1 was fixed to the stage using Lintec's Opteria D692 (thickness 15 μm) adhesive. Under a 25°C environment, the peel force when the support and the cured layer (or support if there is no cured layer) were peeled off at a speed of 5 m / min in a 180° direction from the orientation layer was measured using Aiko Engineering Co., Ltd.'s Digital Force Gauge RZ-1.

[0176] [Peel Force (over time, 65°C, 90% humidity, 300 hours)] The obtained optical film was cut to 150 mm x 25 mm and treated for 300 hours under conditions of 65°C and 90% humidity. After that, the oxygen barrier layer D1 side of the optical film was fixed to the stage using Lintec Opteria D692 (thickness 15 μm) adhesive. At a 25°C environment, the peel force when the support and the cured layer (or support if there is no cured layer) were peeled off at a speed of 5 m / min in a 180° direction from the orientation layer was measured using a digital force gauge RZ-1 manufactured by Aiko Engineering Co., Ltd.

[0177] [Curl] The curl value of each optical film was measured according to the measurement method specified by the American National Standards Institute (ANSI / ASC PH1.29-1985, Method-A). Specifically, the optical film was cut to a size of 35 mm in the width direction and 2 mm in the length direction, and the resulting sample was placed on a curl plate. The curl plate with the sample was conditioned for 6 hours at a temperature of 25°C and a relative humidity of 80%. The curl value read after conditioning was used as the measured value. The curl value is expressed as the radius of curvature (cm), and a larger radius of curvature (absolute value of the curl value) means that the film transport performance is better. From the measured curl values, the curl of each polarizer was evaluated based on the following criteria. Evaluations 1 to 3 are at a level that does not pose a practical problem.

[0178] (Evaluation Criteria) "1": (Absolute value of curl) ≥ 30 cm "2": 30 cm > (Absolute value of curl) ≥ 20 cm "3": 20 cm > (Absolute value of curl) ≥ 10 cm "4": 10 cm > (Absolute value of curl)

[0179] [Results] The table below shows the composition and evaluation results of each optical film. In the table below, "TAC" refers to the cellulose acylate film A1 described above, and "PET" refers to the PET film (Cosmoshine A4265, manufactured by Toyobo Co., Ltd.) described above. In the table below, "Number of functional groups" is the number of polymerizable groups (×10) relative to the molecular weight of the polymerizable compound. －４ ) is shown. In the table below, "Surface Eg" indicates the surface energy of the hardened layer.

[0180]

[0181]

[0182] As shown in the table above, the optical film of the present invention exhibits low initial peeling force between the cured layer (the layer in contact with the orientation layer on the opposite side of the light-absorbing anisotropy layer) and the orientation layer, and also suppresses the increase in peeling force over time. On the other hand, when the optical film did not have a cured layer, the peeling force increased over time (Comparative Examples 1 and 2). Furthermore, even when the optical film had a cured layer, the indentation Knoop hardness was 175 N / mm². ２ When the value was less than 10, it was confirmed that the initial peeling force was large (Comparative Examples 3 and 4). When the thickness of the cured layer was 2.0 μm or less, the curl value of the optical film was larger, and when it was 1.0 μm or less, it was confirmed that the curl value of the optical film was even larger (comparison of Examples 4 to 6, comparison of Example 3 with Examples 1 and 2). The number of polymerizable groups relative to the molecular weight of the polymerizable compound was 80 × 10 －４ In the above cases, it was confirmed that the effects of the present invention are superior (comparison between Examples 4-6 and Examples 1-3). The indentation Knoop hardness of the hardened layer was 200 N / mm². ２ In the above cases, it was confirmed that the effects of the present invention are superior.

[0183] 100 Optical film 102 Support 104 Cured layer 106 Orientation layer 108 Light absorption anisotropy layer 10B Polarizing plate 12 Specific laminate 14 Adhesive layer 16 Phase difference layer

Claims

1. The material comprises, in this order: a support; a cured layer disposed in contact with the support; an oriented layer disposed in contact with the cured layer; and a light-absorbing anisotropic layer disposed in contact with the oriented layer, wherein the cured layer contains a cured product of a compound having polymerizable groups, and the indentation Knoop hardness of the cured layer is 175 N / mm². ２ That concludes the explanation of optical film.

2. The optical film according to claim 1, wherein the polymerizable compound comprises at least one compound selected from the group consisting of polyfunctional acrylates and polyfunctional methacrylates.

3. The number of polymerizable groups in the compound having polymerizable groups relative to its molecular weight is 50.0 × 10 －４ The optical film according to claim 1.

4. The optical film according to claim 1, wherein the surface energy of the cured layer is 34.0 mN / m or more.

5. The optical film according to claim 1, wherein the thickness of the cured layer is 0.5 to 3.5 μm.

6. The optical film according to claim 1, wherein the light-absorbing anisotropic layer is a layer formed using a composition containing a dichroic substance and a liquid crystal compound, and the content of the dichroic substance is 10% by mass or more with respect to the total solid content of the composition.

7. The optical film according to claim 1, wherein the orientation layer is a photo-alignment layer.

8. The optical film according to claim 7, wherein the photo-alignment layer is a layer formed using a composition containing a photo-alignment compound having polymerizable groups.

9. The optical film according to claim 1, wherein the thickness of the orientation layer is 1.0 μm or less.

10. The optical film according to claim 1, wherein the smoothness of the surface of the orientation layer on the cured layer side is 0.20 arcmin or less.

11. The optical film according to claim 1, wherein the total thickness of the cured layer and the orientation layer is 1.0 μm or more.

12. The optical film according to claim 1, wherein the peel force between the cured layer and the orientation layer is 0.02 to 0.30 N / 25 mm.

13. A polarizing plate comprising a laminate obtained by peeling off the support and the cured layer from the optical film according to any one of claims 1 to 12.

14. An image display device comprising a laminate obtained by peeling off the support and the cured layer from the optical film according to any one of claims 1 to 12.

15. An image display device having the polarizing plate described in claim 13.

Images