Composition for forming photo-alignment film, photo-alignment film, optical laminate, photo-alignment polymer, curable composition, and refractive index gradient film

Abstract

The present invention addresses the problem of providing a composition for forming a photo-alignment film, whereby reflection at the interface with a liquid crystal cured layer can be suppressed and a photo-alignment film having high transmittance can be formed, a photo-alignment film, an optical laminate, a photo-alignment polymer, a curable composition, and a refractive index gradient film. This composition for forming a photo-alignment film contains a photo-alignment polymer A, a (meth)acrylate polymer B, and a photo-radical polymerization initiator, wherein the photo-alignment polymer A is a copolymer having a repeating unit a1 represented by formula (a1), a repeating unit a2 represented by formula (a2), and a repeating unit a3 represented by formula (a3), the refractive index of the photo-alignment polymer A in a single film is 1.60 or more, the refractive index of the (meth)acrylate polymer B in a single film is 1.55 or less, and the surface free energy of the cured product of the photo-alignment polymer A and the surface free energy of the cured product of the (meth)acrylate polymer B satisfy formula (1).

Description

Compositions for forming photo-alignment films, photo-alignment films, optical laminates, photo-aligning polymers, curable compositions, and refractive index gradient films.

[0001] The present invention relates to a composition for forming a photo-alignment film, a photo-alignment film, an optical laminate, a photo-aligning polymer, a curable composition, and a refractive index gradient film.

[0002] Optical films, such as optical compensation sheets and phase difference films, are used in various image display devices due to their ability to eliminate image coloration and expand viewing angles. While stretched birefringent films were previously used as optical films, in recent years, liquid crystal cured layers formed using liquid crystal compounds have been proposed as an alternative to stretched birefringent films.

[0003] When forming such a liquid crystal hardened layer, a photo-alignment film obtained by photo-alignment treatment may be used to orient the liquid crystal compound. For example, Patent Document 1 describes a photo-alignment film containing at least one specific compound selected from the group consisting of polymerizable polymers having polymerizable groups in their side chains and polymers of polymerizable polymers, and when the secondary ion intensity originating from the specific compound in the photo-alignment film is measured by time-of-flight secondary ion mass spectrometry while irradiating the photo-alignment film from the liquid crystal layer hardened layer side surface toward the substrate side surface, the maximum value of the secondary ion intensity originating from the specific compound is located in a region up to a thickness of 100 nm from the substrate side surface ([Claim 1][Claim 3]).

[0004] International Publication No. 2023 / 214502

[0005] The present inventors investigated the photoalignment film described in Patent Document 1 and found that, depending on the type of liquid crystal curing layer (particularly the cholesteric liquid crystal layer), there is room to suppress reflection at the interface between the photoalignment film and the liquid crystal curing layer. Furthermore, the present inventors found that, from the viewpoint of suppressing reflection at the interface between the photoalignment film and the liquid crystal curing layer, forming a photoalignment film using a composition containing multiple types of polymers may reduce the transmittance of the photoalignment film.

[0006] Therefore, the object of the present invention is to provide a photoalignment film forming composition, a photoalignment film, an optical laminate, a photoalignable polymer, a curable composition, and a refractive index gradient film that can suppress reflection at the interface with the liquid crystal cured layer and form a photoalignment film with high transmittance.

[0007] As a result of diligent research into the above-mentioned problems, the inventors have discovered that a photo-alignment film-forming composition containing a photo-aligning polymer and a (meth)acrylate polymer that satisfy a predetermined relationship in terms of refractive index and surface free energy can suppress reflection at the interface with the liquid crystal curing layer and form a photo-alignment film with high transmittance, thereby completing the present invention. In other words, the inventors have found that the above-mentioned problems can be solved by the following configuration.

[0008] [1] A photo-alignment film-forming composition comprising a photo-aligning polymer A, a (meth)acrylate polymer B, and a photoradical polymerization initiator, wherein the photo-aligning polymer A is a copolymer having repeating units a1 represented by formula (a1) described later, repeating units a2 represented by formula (a2) described later, and repeating units a3 represented by formula (a3) ​​described later, the refractive index at 589 nm of a single film of the photo-aligning polymer A is 1.60 or more at 23°C, the refractive index at 589 nm of a single film of the (meth)acrylate polymer B is 1.55 or less at 23°C, and when the surface free energy of the cured product of the photo-aligning polymer A is SFEA and the surface free energy of the cured product of the (meth)acrylate polymer B is SFEB, the photo-alignment film-forming composition satisfies the following formula (1): 5 < SFEB - SFEA < 25 (1) [2] L in formula (a1) described later １ However, the formula (L) described later １ -1) to (L １ A photo-alignment film-forming composition according to [1], representing any of the divalent linking groups in -11). [3] R in formula (a2) described later. ８The photo-alignment film-forming composition according to [1] or [2], wherein the substituent comprises at least one selected from the group consisting of a sulfur atom, an iodine atom, a bromine atom, and a naphthalene ring. [4] The photo-alignment film-forming composition according to any one of [1] to [3], wherein the repeating unit a2 represents any of the repeating units of formulas (a2-1) to (a2-5) described later. [5] The photo-alignment film-forming composition according to any one of [1] to [4], wherein the (meth)acrylate polymer B is a copolymer having a repeating unit b1 represented by formula (b1) described later and a repeating unit b2 represented by formula (b2) described later. [6] The photo-alignment film-forming composition according to any one of [1] to [5], wherein the ratio of the content of (meth)acrylate polymer B to the content of photo-aligning polymer A is 30 / 70 to 70 / 30. [7] A photo-alignment film forming composition according to any one of [1] to [6], wherein the weight-average molecular weight of the photo-aligning polymer A is 30,000 or less, and the weight-average molecular weight of the (meth)acrylate polymer B is 10,000 or less. [8] A photo-alignment film obtained by curing the photo-alignment film forming composition according to any one of [1] to [7], having orientation control ability on its surface. [9] A photo-alignment film according to [8], wherein when an ion beam is irradiated from one surface X to the other surface Y of the photo-alignment film by time-of-flight secondary ion mass spectrometry, and the peak intensity of ion fragments derived from the repeating unit a2 of the photo-aligning polymer A according to claim 1 is measured, the peak intensity Px at a position 50 nm from surface X in the thickness direction of the photo-alignment film and the peak intensity Py at a position 50 nm from surface Y in the thickness direction of the photo-alignment film satisfy the following formula (2). 1.5 ≤ (Px / Py) (2)

[10] An optical laminate having a cured layer and a photoalignment film according to [8] or [9], wherein the cured layer comprises a cured product of a composition containing a copolymer C having repeating units c1 represented by formula (c1) described later and repeating units c2 represented by formula (c2) described later.

[11] The optical laminate according to

[10] , further comprising a transparent support on the side of the cured layer opposite to the photoalignment film.

[12] The optical laminate according to

[10] or

[11] , further comprising a liquid crystal cured layer on the side of the photoalignment film opposite to the cured layer.

[13] An optical laminate according to any one of

[10] to

[12] , wherein the thickness of the photo-alignment film is 200 nm to 5 μm.

[14] A photo-alignable polymer having a repeating unit a1 represented by formula (a1) described later, a repeating unit a2 represented by formula (a2) described later, and a repeating unit a3 represented by formula (a3) ​​described later.

[15] A curable composition comprising a curable polymer A10, a (meth)acrylate polymer B, and a photoradical polymerization initiator, wherein the curable polymer A10 is a copolymer having repeating units a20 represented by formula (a20) described later and repeating units a30 represented by formula (a30) described later, the refractive index of a single film of curable polymer A10 at 589 nm is 1.60 or more at 23°C, the refractive index of a single film of (meth)acrylate polymer B at 589 nm is 1.55 or less at 23°C, and when the surface free energy of the cured product of curable polymer A10 is SFEA and the surface free energy of the cured product of (meth)acrylate polymer B is SFEB, the curable composition satisfies the following formula (1): 5 < SFEB - SFEA < 25 (1)

[16] A refractive index gradient film obtained by curing the curable composition described in

[15] .

[0009] As shown below, the present invention provides a photo-alignment film forming composition, a photo-alignment film, an optical laminate, a photo-alignable polymer, a curable composition, and a refractive index gradient film that can suppress reflection at the interface with the liquid crystal cured layer and form a photo-alignment film with high transmittance.

[0010] The present invention will now be described in detail. The following descriptions of constituent elements may be based on representative embodiments of the present invention, but the present invention is not limited to such embodiments. In this specification, numerical ranges represented by "~" mean a range that includes the numbers written before and after "~" as the lower and upper limits. In this specification, an upper or lower limit stated in a numerical range described in steps may be replaced with an upper or lower limit in another numerical range described in steps. In addition, an upper or lower limit stated in a numerical range described in this specification may be replaced with a value shown in the examples. In this specification, "(meth)acrylate" is a notation that represents "acrylate" or "methacrylate", "(meth)acrylic" is a notation that represents "acrylic" or "methacrylic", and "(meth)acryloyl" is a notation that represents "acryloyl" or "methacryloyl". Next, terms used in this specification will be explained.

[0011] [Slow Axis] In this specification, the "slow axis" refers to the direction in which the refractive index is maximum within the plane. When referring to the slow axis of an optically anisotropic layer, it refers to the slow axis of the entire optically anisotropic layer.

[0012] [Re(λ), Rth(λ)] In this specification, Re(λ) and Rth(λ) represent the in-plane retardation and thickness-direction retardation at wavelength λ, respectively. Unless otherwise specified, wavelength λ is 550 nm. Here, the values ​​for in-plane retardation and thickness-direction retardation are those measured using an AxoScan OPMF-1 (manufactured by OptoScience Co., Ltd.) with light of the measurement wavelength. Specifically, by inputting the average refractive index ((Nx + Ny + Nz) / 3) and film thickness (d) into the AxoScan OPMF-1, the following can be calculated: In the slow axis direction (°) Re(λ) = R0(λ) Rth(λ) = ((nx + ny) / 2 - nz) × d Note that R0(λ) is displayed as a value calculated by AxoScan OPMF-1, but it means Re(λ).

[0013] [Thickness] In this specification, the thickness (film thickness) of the photo-aligned film and the thickness of each layer in the optical laminate are measured by observing the cross-section of the film with a scanning electron microscope and taking the average value of the measurement results at any three points.

[0014] [Substituents] In this specification, examples of substituents (monovalent substituents) include the substituents listed in substituent group A below. In this specification, "may have substituents" includes not only embodiments without substituents but also embodiments having one or more substituents. <Substituent Group A> Substituents include, for example, halogen atoms (e.g., fluorine atom, chlorine atom, bromine atom, preferably chlorine atom, fluorine atom, more preferably fluorine atom); alkyl groups (preferably C1 to C48, more preferably C1 to C24, particularly preferably C1 to C8 alkyl groups, for example, C1 to C6 linear alkyl groups (e.g., methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group), C3 to C6 branched alkyl groups (e.g., isopropyl group, isobutyl group, tert-butyl group, sec-butyl group, neopentyl group, isohexyl group, 3-methylpentyl group), C3 to C12 cyclic alkyl groups (e.g., cyclopropyl group, cyclopentyl group, cyclohexyl group, 1-norbornyl group, 1-adamantyl group)); Alkenyl groups (preferably 2 to 48 C12, more preferably 2 to 18 C12 alkenyl groups, for example vinyl groups, allyl groups, 1-butenyl groups, 2-butenyl groups); Alkynyl groups (preferably 2 to 6 C12 alkynyl groups, more preferably 2 to 4 C12 alkynyl groups, for example ethynyl groups, 1-propynyl groups, propargyl groups, 1-butynyl groups, 2-butynyl groups); Aryl groups (preferably 6 to 48 C12, more preferably 6 to 24 C12 aryl groups, for example phenyl groups, oligoaryl groups (naphthyl groups, anthryl groups), phenanthrenyl groups, fluorenyl groups, pyrenyl groups, triphenylenyl groups, biphenyl groups); Heteroaryl groups (preferably heterocyclic groups having 1 to 32 carbon atoms, more preferably 1 to 18 carbon atoms, for example, 2-thienyl group, 4-pyridyl group, 2-furyl group, 2-pyrimidinyl group, 1-pyridyl group, 2-benzothiazolyl group, 1-imidazolyl group, 1-pyrazolyl group, benzotriazole-1-yl group);Arylalkyl groups (preferably arylalkyl groups having 7 to 15 carbon atoms, for example, benzyl group, phenethyl group, methylbenzyl group, phenylpropyl group, 1-methylphenylethyl group, phenylbutyl group, 2-methylphenylpropyl group, tetrahydronaphthyl group, naphthylmethyl group, naphthylethyl group, indenyl group, fluorenyl group, anthracenylmethyl group (anthrylmethyl group), phenanthrylmethyl group (phenanthrylmethyl group)); silyl groups (preferably silyl groups having 3 to 38 carbon atoms, more preferably silyl groups having 3 to 18 carbon atoms, for example, trimethylsilyl group, triethylsilyl group, tributylsilyl group, t-butyldimethylsilyl group, t-hexyldimethylsilyl group); hydroxyl groups; cyano groups; nitro groups; morpholino groups; Alkoxy groups (preferably alkoxy groups having 1 to 48 carbon atoms, more preferably 1 to 24 carbon atoms, for example, methoxy group, ethoxy group, 1-butoxy group, 2-butoxy group, isopropoxy group, t-butoxy group, dodecyloxy group, cycloalkyloxy group (for example, cyclopentyloxy group, cyclohexyloxy group)); aryloxy groups (preferably aryloxy groups having 6 to 48 carbon atoms, more preferably 6 to 24 carbon atoms, for example, phenoxy group, 1-naphthoxy group); alkenyloxy groups (preferably alkenyloxy groups having 2 to 6 carbon atoms, for example, vinyloxy group, 1-propenyloxy group, 2-n-propenyloxy group (allyloxy group), 1-n-butenyloxy group, prenyloxy group); Heterocyclic oxy groups (preferably heterocyclic oxy groups having 1 to 32 carbon atoms, more preferably 1 to 18 carbon atoms, for example, 1-phenyltetrazole-5-oxy group, 2-tetrahydropyranyloxy group); heterocyclic alkyl groups (preferably heterocyclic alkyl groups having 1 to 32 carbon atoms, more preferably 1 to 18 carbon atoms, for example, tetrahydropyranylethyl group); silyloxy groups (preferably silyloxy groups having 1 to 32 carbon atoms, more preferably 1 to 18 carbon atoms, for example, trimethylsilyloxy group, t-butyldimethylsilyloxy group, diphenylmethylsilyloxy group);Acyloxy groups (preferably acyloxy groups having 2 to 48 carbon atoms, more preferably acyloxy groups having 2 to 24 carbon atoms, for example, acetoxy group, pivaloyloxy group, benzoyloxy group, dodecanoyloxy group, acryloyloxy group, methacryloyloxy group); hydroxyalkyl groups (preferably hydroxyalkyl groups having 2 to 10 carbon atoms, for example, hydroxyethyl group); hydroxyalkyleneoxy groups (preferably hydroxyalkyleneoxy groups having 2 to 10 carbon atoms, for example, hydroxyethyleneoxy group); alkoxycarbonyloxy groups (preferably alkoxycarbonyloxy groups having 2 to 48 carbon atoms, more preferably alkoxycarbonyloxy groups having 2 to 24 carbon atoms, for example, ethoxycarbonyloxy group, t-butoxycarbonyloxy group, cycloalkyloxycarbonyloxy group (for example, cyclohexyloxycarbonyloxy group)); Aryloxycarbonyloxy groups (preferably aryloxycarbonyloxy groups having 7 to 32 carbon atoms, more preferably 7 to 24 carbon atoms, for example, phenoxycarbonyloxy group); Carbamoyloxy groups (preferably carbamoyloxy groups having 1 to 48 carbon atoms, more preferably 1 to 24 carbon atoms, for example, N,N-dimethylcarbamoyloxy group, N-butylcarbamoyloxy group, N-phenylcarbamoyloxy group, N-ethyl-N-phenylcarbamoyloxy group); Sulfamoyloxy groups (preferably sulfamoyloxy groups having 1 to 32 carbon atoms, more preferably 1 to 24 carbon atoms, for example, N,N-diethylsulfamoyloxy group, N-propylsulfamoyloxy group); Alkylsulfonyloxy groups (preferably alkylsulfonyloxy groups having 1 to 38 carbon atoms, more preferably 1 to 24 carbon atoms, for example, methylsulfonyloxy group, hexadecylsulfonyloxy group, cyclohexylsulfonyloxy group); Aryl sulfonyloxy groups (preferably aryl sulfonyloxy groups having 6 to 32 carbon atoms, more preferably aryl sulfonyloxy groups having 6 to 24 carbon atoms, for example, phenyl sulfonyloxy groups); Acyl groups (preferably acyl groups having 1 to 48 carbon atoms, more preferably acyl groups having 1 to 24 carbon atoms, for example, formyl groups, acetyl groups, acryloyl groups, methacryloyl groups, pivaloyl groups, benzoyl groups, tetradecanoyl groups, cyclohexanoyl groups);Alkoxycarbonyl groups (preferably alkoxycarbonyl groups having 2 to 48 carbon atoms, more preferably 2 to 24 carbon atoms, for example, methoxycarbonyl group, ethoxycarbonyl group, octadecyloxycarbonyl group, cyclohexyloxycarbonyl group, 2,6-di-tert-butyl-4-methylcyclohexyloxycarbonyl group); aryloxycarbonyl groups (preferably aryloxycarbonyl groups having 7 to 32 carbon atoms, more preferably 7 to 24 carbon atoms, for example, phenoxycarbonyl group); Carbamoyl groups (preferably carbamoyl groups having 1 to 48 carbon atoms, more preferably 1 to 24 carbon atoms, for example, carbamoyl group, N,N-diethylcarbamoyl group, N-ethyl-N-octylcarbamoyl group, N,N-dibutylcarbamoyl group, N-propylcarbamoyl group, N-phenylcarbamoyl group, N-methylN-phenylcarbamoyl group, N,N-dicyclohexylcarbamoyl group); amino groups (preferably amino groups having 32 or fewer carbon atoms, more preferably 24 or fewer carbon atoms, for example, amino group, methylamino group, N,N-dimethylamino group, N,N-dibutylamino group, tetradecylamino group, 2-ethylhexylamino group, cyclohexylamino group); anilino groups (preferably anilino groups having 6 to 32 carbon atoms, more preferably 6 to 24 carbon atoms, for example, anilino group, N-methylanilino group); Heterocyclic amino groups (preferably heterocyclic amino groups having 1 to 32 carbon atoms, more preferably 1 to 18 carbon atoms, for example, 4-pyridylamino group); carbonamide groups (preferably carbonamide groups having 2 to 48 carbon atoms, more preferably 2 to 24 carbon atoms, for example, acetamide group, benzamide group, tetradecaneamide group, pivaloylamide group, cyclohexaneamide group); ureido groups (preferably carbonamide groups having 1 to 32 carbon atoms, more preferably carbonamide groups having 1 to 24 carbon atoms, for example, ureido group, N,N-dimethylureido group, N-phenylureido group); imide groups (preferably imide groups having 36 carbon atoms or less, more preferably carbon atoms of 24 carbon atoms or less, for example, N-succinimide group, N-phthalimide group);Alkoxycarbonylamino groups (preferably alkoxycarbonylamino groups having 2 to 48 carbon atoms, more preferably 2 to 24 carbon atoms, for example, methoxycarbonylamino group, ethoxycarbonylamino group, t-butoxycarbonylamino group, octadecyloxycarbonylamino group, cyclohexyloxycarbonylamino group); aryloxycarbonylamino groups (preferably aryloxycarbonylamino groups having 7 to 32 carbon atoms, more preferably 7 to 24 carbon atoms, for example, phenoxycarbonylamino group); sulfonamide groups (preferably sulfonamide groups having 1 to 48 carbon atoms, more preferably 1 to 24 carbon atoms, for example, methanesulfonamide group, butanesulfonamide group, benzenesulfonamide group, hexadecanesulfonamide group, cyclohexanesulfonamide group); Sulfamoylamino groups (preferably C1-C48, more preferably C1-C24 sulfamoylamino groups, for example, N,N-dipropylsulfamoylamino group, N-ethyl-N-dodecylsulfamoylamino group); Azo groups (preferably C1-C32, more preferably C1-C24 azo groups, for example, phenylazo group, 3-pyrazolylazo group); Alkylthio groups (preferably C1-C48, more preferably C1-C24 alkylthio groups, for example, methylthio group, ethylthio group, octylthio group, cyclohexylthio group); Arylthio groups (preferably C6-C48, more preferably C6-C24 arylthio groups, for example, phenylthio group); Heterocyclic thio groups (preferably C1-C32, more preferably C1-C18 heterocyclic thio groups, for example, 2-benzothiazolylthio group, 2-pyridylthio group, 1-phenyltetrazolylthio group); Alkyl sulfinyl group (preferably an alkyl sulfinyl group having 1 to 32 carbon atoms, more preferably an alkyl sulfinyl group having 1 to 24 carbon atoms, for example, dodecane sulfinyl group); aryl sulfinyl group (preferably an aryl sulfinyl group having 6 to 32 carbon atoms, more preferably an aryl sulfinyl group having 6 to 24 carbon atoms, for example, phenyl sulfinyl group);An alkylsulfonyl group (preferably an alkylsulfonyl group having 1 to 48 carbon atoms, more preferably 1 to 24 carbon atoms, for example, methylsulfonyl group, ethylsulfonyl group, propylsulfonyl group, butylsulfonyl group, isopropylsulfonyl group, 2-ethylhexylsulfonyl group, hexadecylsulfonyl group, octylsulfonyl group, cyclohexylsulfonyl group); an arylsulfonyl group (preferably an arylsulfonyl group having 6 to 48 carbon atoms, more preferably 6 to 24 carbon atoms, for example, phenylsulfonyl group, 1-naphthylsulfonyl group); a sulfamoyl group (preferably a sulfamoyl group having 32 or fewer carbon atoms, more preferably 24 or fewer carbon atoms, for example, sulfamoyl group, N,N-dipropylsulfamoyl group, N-ethyl-N-dodecylsulfamoyl group, N-ethyl-N-phenylsulfamoyl group, N-cyclohexylsulfamoyl group, N-(2-ethylhexyl)sulfamoyl group); a phosphonyl group (preferably a phosphonyl group having 1 to 32 carbon atoms, more preferably 1 to 24 carbon atoms, for example, phenoxyphosphonyl group, octyloxyphosphonyl group, phenylphosphonyl group); a phosphinoylamino group (preferably a phosphinoylamino group having 1 to 32 carbon atoms, more preferably 1 to 24 carbon atoms, for example, diethoxyphosphinoylamino group, dioctyloxyphosphinoylamino group); an epoxy group; -NHCOCH; ３ ; -SO ２ NH C ２ H ４ OCH ３ ; -NHSO ２ CH ３ ; etc. may be mentioned, and two or more of these may be combined. These substituents may be further substituted by these substituents. Also, when having two or more substituents, they may be the same or different from each other. Also, when possible, they may be bonded to each other to form a ring.

[0015] [Composition for Photo-Alignment Film Formation] The photo-alignment film formation composition of the present invention (hereinafter also simply referred to as "the composition of the present invention") is a composition containing a photo-aligning polymer A, a (meth)acrylate polymer B, and a photoradical polymerization initiator. The photo-aligning polymer A is a copolymer having repeating units a1 represented by formula (a1) described later, repeating units a2 represented by formula (a2) described later, and repeating units a3 represented by formula (a3) ​​described later. The refractive index of a single film of the photo-aligning polymer A at 589 nm is 1.60 or higher at 23°C. The refractive index of a single film of the (meth)acrylate polymer B at 589 nm is 1.55 or lower at 23°C. Furthermore, when the surface free energy of the cured product of the photo-aligning polymer A is SFEA and the surface free energy of the cured product of the (meth)acrylate polymer B is SFEB, the following formula (1) is satisfied. In this invention, if at least one of photo-oriented polymer A and (meth)acrylate polymer B is included in two or more types, it is sufficient that the following formula (1) is satisfied in at least one combination of photo-oriented polymer A and (meth)acrylate polymer B: 5 < SFEB - SFEA < 25 (1)

[0016] [Refractive Index] The refractive index at 589 nm of a single film of photo-oriented polymer A and the refractive index at 589 nm of a single film of (meth)acrylate polymer B refer to the values ​​measured by the following sample preparation method and measurement method. In the following, the refractive index at 589 nm measured at 23°C will also be simply abbreviated as "refractive index". <Sample Preparation Method> First, 90 mg of the photo-oriented polymer A or (meth)acrylate polymer B to be measured is weighed out and dissolved in 2910 mg of cyclohexanone to prepare a coating solution. Next, each coating solution is spin-coated onto a quartz substrate to create a single-film spin-coated film, which is used as a sample for refractive index measurement. <Measurement Method> The refractive index at a wavelength of 589 nm is measured at 23°C using an ellipsometer (manufactured by J.A. Wollam, product name: M-2000XI-210) for the refractive index measurement sample prepared above.

[0017] [Surface Free Energy] The surface free energy (SFEA) of the cured product of photo-oriented polymer A and the surface free energy (SFEB) of the cured product of (meth)acrylate polymer B are the values ​​measured by the following sample preparation and measurement methods. <Sample Preparation Method> Dissolve 148.5 mg of the photo-oriented polymer A or (meth)acrylate polymer B, which is the target of measurement, and the polymerization initiator S-1 (1.5 mg) below in 2850 mg of cyclohexanone to prepare a coating solution. Spin coat the coating solution onto a glass substrate to create a spin-coated film, and irradiate it with an ultraviolet irradiator equipped with a 313 nm cut filter at an irradiation dose of 500 mJ / cm². ２ The sample is cured and prepared for surface free energy measurement. <Measurement Method> For the surface free energy measurement sample prepared above, the contact angle θ was measured using a contact angle meter 2.2 seconds after dropping in water and diiodomethane. Ｈ２Ｏ and θ ＣＨ２Ｉ２ Using the following Owens surface free energy calculation formula, the surface free energy γ Ｓｖ ｈ (mJ / m ２ Derive ) . 1 + cosθ Ｈ２Ｏ = 2√γ Ｓ ｄ (√γ Ｈ２Ｏ ｄ / γ Ｈ２Ｏ，Ｖ ) + 2√γ Ｓ ｈ (√γ Ｈ２Ｏ ｈ / γ Ｈ２Ｏ，Ｖ ) 1 + cosθ ＣＨ２Ｉ２ = 2√γ Ｓ ｄ (√γ ＣＨ２Ｉ２ ｄ / γ ＣＨ２Ｉ２，Ｖ ) + 2√γ Ｓ ｈ (√γ ＣＨ２Ｉ２ ｈ / γ ＣＨ２Ｉ２，Ｖ ) γ Ｓｖ ｈ = γ Ｓ ｄ +γ Ｓ ｈ The constants for water and diiodomethane used were as follows: γ Ｈ２Ｏｄ : 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

[0018] Polymerization initiator S-1

[0019] In the present invention, by blending a photo-aligning polymer A and a (meth)acrylate polymer B that satisfy the above-described relationship in terms of refractive index and surface free energy, it is possible to suppress reflection at the interface with the liquid crystal cured layer and form a photo-aligned film with high transmittance. Although the mechanism is not fully understood, it is presumed to be approximately as follows. First, the surface free energy (SFEA) of the cured product of the photo-aligning polymer A and the surface free energy (SFEB) of the cured product of the (meth)acrylate polymer B satisfy formula (1) above, so that the photo-aligning polymer A and the (meth)acrylate polymer B separate to an appropriate extent without causing phase separation. Therefore, for example, when the composition of the present invention is applied to a substrate to form a photo-aligned film, the photo-aligning polymer A will be predominantly located on the air interface side, and the (meth)acrylate polymer B will be predominantly located on the substrate interface side. Furthermore, since the refractive index of a single film of the photo-aligning polymer A at 589 nm is 1.60 or higher at 23°C, and the refractive index of a single film of the (meth)acrylate polymer B at 589 nm is 1.55 or lower at 23°C, the resulting photo-alignment film is a refractive index gradient film in which the refractive index changes in the thickness direction. For example, when the composition of the present invention is applied to a substrate to form a photo-alignment film, the refractive index on the air interface side becomes higher, and the refractive index on the substrate interface side becomes lower. From the above, it is considered that the composition of the present invention was able to suppress reflection at the interface with the liquid crystal curing layer and form a photo-alignment film with high transmittance.

[0020] In the present invention, the refractive index of a single film of the photo-oriented polymer A is preferably 1.60 or more and 1.75 or less, and more preferably 1.60 or more and 1.70 or less. Similarly, the refractive index of a single film of the (meth)acrylate polymer B is preferably 1.35 or more and 1.55 or less, and more preferably 1.45 or more and 1.55 or less.

[0021] In the present invention, the surface free energy (SFEA) of the cured product of the photo-oriented polymer A and the surface free energy (SFEB) of the cured product of the (meth)acrylate polymer B preferably satisfy the following formula (1-1), and more preferably satisfy the following formula (1-2): 5 < SFEB - SFEA < 20 (1-1) 5 < SFEB - SFEA < 15 (1-2)

[0022] [Photo-Oriented Polymer A] The photo-oriented polymer A contained in the composition of the present invention is a copolymer having a repeating unit a1 represented by the following formula (a1), a repeating unit a2 represented by the following formula (a2), and a repeating unit a3 represented by the following formula (a3). In addition, the photo-oriented polymer A may have any repeating units other than repeating units a1 to a3.

[0023] In the above formula (a1), R １ L represents a hydrogen atom or a methyl group. １ represents a divalent linking group, R ２ ~R ６ Each of these independently represents a hydrogen atom or a substituent. In the above formula (a2), R ７ X represents a hydrogen atom or a methyl group. １ represents -O-, -S-, or -NH-, R ８ R represents a substituent. However, the refractive index at 589 nm of a single film of the homopolymer having the repeating unit represented by formula (a2) above satisfies the condition that it is 1.68 or higher at 23°C. In formula (a3) ​​above, R ９ X represents a hydrogen atom or a methyl group. ２ represents -O-, -S-, or -NH-, L ２represents an n+1 valent linking group, where n is an integer from 1 to 3, and P １ This represents a crosslinking group. However, if n is 2 or 3, multiple P １ These may be the same or different.

[0024] In the present invention, the L in formula (a1) above is used because it improves the orientation control ability of the photo-alignment film. １ However, the following formula (L １ -1) to (L １ -11) Preferably, it represents one of the divalent linking groups shown below. １ -1) to (L １ -11) where *1 is the main chain in formula (a1) above (i.e., R １ *2 indicates the bond position with the carbon atom bonded to the carbonyl group.

[0025] In the above formula (a1), R ２ ~R ６ Examples of substituents represented by one aspect include those listed in substituent group A above, among which alkyl groups, alkoxy groups, halogen atoms, aryl groups, aryloxy groups, hydroxyl groups, cyano groups, and amino groups are preferred, and halogen atoms, aryl groups, aryloxy groups, hydroxyl groups, cyano groups, and amino groups are more preferred. Also, R in formula (a1) above ２ , R ３ , R ５ and R ６ It is preferable that it be a hydrogen atom. Also, R in the above formula (a1) ４ The substituent is preferably a substituent, more preferably an alkoxy group, and even more preferably an alkoxy group having 6 to 16 carbon atoms.

[0026] R in the above formula (a2) ８ The substituent represented by is not particularly limited, but it is preferable that the substituent is such that the refractive index at 589 nm of a single film of the homopolymer having the repeating unit represented by formula (a2) above is 1.68 or higher at 23°C.

[0027] In the present invention, R in formula (a2) above is used because it is possible to further suppress reflection at the interface with the liquid crystal hardened layer and to form a photo-alignment film with higher transmittance. ８ However, it is preferable that the substituent includes at least one selected from the group consisting of a sulfur atom, an iodine atom, a bromine atom, and a naphthalene ring.

[0028] In the present invention, it is preferable that the repeating unit a2 represented by the above formula (a2) is one of the repeating units of the following formulas (a2-1) to (a2-5) in order to further suppress reflection at the interface with the liquid crystal hardened layer and to form a photo-aligned film with even higher transmittance. ７ represents a hydrogen atom or a methyl group.

[0029] In the above formula (a3), L ２ The n+1 valent linking group represented by is preferably an n+1 valent hydrocarbon group having 1 to 24 carbon atoms, which may have substituents, and in which some of the carbon atoms constituting the hydrocarbon group may be substituted with heteroatoms; more preferably, it is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, which may contain oxygen or nitrogen atoms.

[0030] The number of carbon atoms in the n+1 valent linking group is not particularly limited, but is preferably 1 to 24, and more preferably 1 to 10, for the reason that the orientation control ability of the photo-aligned film is further improved. A divalent linking group is preferred as the n+1 valent linking group. Examples of preferred divalent linking groups include optionally substituted divalent hydrocarbon groups, optionally substituted divalent heterocyclic groups, -O-, -S-, -N(Q)-, -CO-, or groups combining these. Q represents a hydrogen atom or a substituent. Examples of divalent hydrocarbon groups include C1 to C10 alkylene groups, C1 to C10 alkenylene groups, divalent aliphatic hydrocarbon groups such as C1 to C10 alkylylene groups, and divalent aromatic hydrocarbon groups such as arylene groups. Examples of divalent heterocyclic groups include divalent aromatic heterocyclic groups, specifically pyridylene groups (pyridine-diyl groups), pyridazine-diyl groups, imidazole-diyl groups, thienylene groups (thiophene-diyl groups), and quinolylene groups (quinoline-diyl groups). Groups combining these include groups that combine at least two selected from the group consisting of divalent hydrocarbon groups, divalent heterocyclic groups, -O-, -S-, -N(Q)-, and -CO-, for example -O-divalent hydrocarbon group-, -divalent hydrocarbon group-O-, and -divalent hydrocarbon group-N(Q)-. Substituents that the above-mentioned divalent hydrocarbon groups (including alkylene groups, etc.) and divalent heterocyclic groups may have, as well as substituents represented by one aspect of Q, are those listed in substituent group A above.

[0031] In the above formula (a3), n represents an integer from 1 to 3, and is preferably 1 or 2.

[0032] Also, P in formula (a3) ​​above １The crosslinkable group represented by is not particularly limited, but radical polymerizable groups (radical polymerizable groups) and cationic polymerizable groups (cationic polymerizable groups) are preferred. Known radical polymerizable groups can be used as radical polymerizable groups, and among them, (meth)acryloyloxy groups are preferred. Examples of cationic polymerizable groups include epoxy groups, epoxycyclohexyl groups, and oxetanyl groups.

[0033] The content of repeating units a1 in the above photo-oriented polymer A is not particularly limited, but is preferably 5 to 50% by mass, and more preferably 10 to 40% by mass, relative to the total repeating units of the photo-oriented polymer A. The content of repeating units a2 in the above photo-oriented polymer A is not particularly limited, but is preferably 20 to 80% by mass, and more preferably 40 to 60% by mass, relative to the total repeating units of the photo-oriented polymer A. Furthermore, the content of repeating units a2 is preferably 100 to 800 parts by mass per 100 parts by mass of the content of repeating units a1. Furthermore, the content of repeating units a3 in the above photo-oriented polymer A is not particularly limited, but is preferably 5 to 50% by mass, and more preferably 10 to 40% by mass, relative to the total repeating units of the photo-oriented polymer A.

[0034] Examples of the repeating unit a1 represented by the above formula (a1) include the repeating units a1-1 to a1-39 described below.

[0035] Examples of the repeating unit a2 represented by the above formula (a2) include the repeating units a2-1 to a2-10 described below.

[0036] Examples of the repeating unit a3 represented by the above formula (a3) ​​include the repeating units a3-1 to a3-60 described below.

[0037] Examples of the photo-oriented polymer A include combinations of specific examples of the repeating units a1 to a3 exemplified above.

[0038] In the present invention, the weight-average molecular weight of the photo-oriented polymer A is preferably 30,000 or less, more preferably 3,000 to 30,000, and even more preferably 4,000 to 25,000. Here, the weight-average molecular weight is the value measured by gel permeation chromatography (GPC) under the following conditions: Solvent (eluent): THF (tetrahydrofuran) Instrument name: TOSOH HLC-8320GPC Column: Three TOSOH TSKgel Super HZM-H (4.6 mm × 15 cm) columns connected together Column temperature: 40°C Sample concentration: 0.1% by mass Flow rate: 1.0 ml / min Calibration curve: A calibration curve using seven TOSOH TSK standard polystyrene samples with Mw = 2,800,000 to 1,050 (Mw / Mn = 1.03 to 1.06) was used.

[0039] Furthermore, in the present invention, the content of the photo-oriented polymer A is preferably 20 to 80% by mass, and more preferably 30 to 60% by mass, based on the total mass of the solids in the composition of the present invention.

[0040] [(Meth)acrylate polymer B] The (meth)acrylate polymer B contained in the composition of the present invention is not particularly limited as long as it is a (meth)acrylic polymer having a refractive index of 1.55 or less in a single film.

[0041] In the present invention, since it is possible to form a photo-alignment film that further suppresses reflection at the interface with the liquid crystal cured layer and has a higher transmittance, the above (meth)acrylate polymer B is preferably a copolymer having a repeating unit b1 represented by the following formula (b1) and a repeating unit b2 represented by the following formula (b2).

[0042] In the above formula (b1), R １０ represents a hydrogen atom or a methyl group, and X ３ represents -O- or -NH-, and R １１ represents a substituent having 1 to 16 carbon atoms. In the above formula (b2), R １２ represents a hydrogen atom or a methyl group, X ４ represents -O-, L ３ represents an n + 1-valent linking group, n represents an integer of 1 to 3, and P ２ represents a crosslinkable group. However, when n is 2 or 3, the plurality of P ２ may be the same or different from each other. Incidentally, examples of the n + 1-valent linking group represented by L ３ and the crosslinkable group represented by P ２ include the same ones as those described for L ２ and P １ in the above formula (a3).

[0043] Examples of the substituent having 1 to 16 carbon atoms represented by R １１ in the above formula (b1) include those having 16 or less carbon atoms among the substituents described in the above-mentioned substituent group A. Among these, an alkyl group, an arylalkyl group, a hydroxyalkyl group, and a heterocyclic alkyl group are preferable.

[0044] The content of the repeating unit b1 in the above (meth)acrylate polymer B is not particularly limited, but is preferably 20 to 95% by mass, more preferably 50 to 90% by mass, based on all the repeating units of the (meth)acrylate polymer B. Also, the content of the repeating unit b2 in the above (meth)acrylate polymer B is not particularly limited, but is preferably 5 to 80% by mass, more preferably 10 to 50% by mass, based on all the repeating units of the (meth)acrylate polymer B.

[0045] Examples of the repeating unit b1 represented by the above formula (b1) include the repeating units b1-1 to b1-20 described below.

[0046] Examples of the repeating unit b2 represented by the above formula (b2) include the repeating units b2-1 to b2-48 described below.

[0047] Examples of the (meth)acrylate polymer B mentioned above include combinations of specific examples of the repeating units b1 and b2 exemplified above.

[0048] In the present invention, the weight-average molecular weight of the (meth)acrylate polymer B is preferably 10,000 or less, more preferably 1,000 to 10,000, and even more preferably 2,000 to 9,000.

[0049] Furthermore, in the present invention, the content of the (meth)acrylate polymer B is preferably 20 to 80% by mass, and more preferably 35 to 65% by mass, based on the total mass of the solids in the composition of the present invention.

[0050] In the present invention, for the reason that reflection at the interface with the liquid crystal cured layer can be further suppressed and a photo-alignment film with higher transmittance can be formed, the ratio of the content of the (meth)acrylate polymer B to the content of the photo-aligning polymer A is preferably 30 / 70 to 70 / 30, and more preferably 35 / 65 to 65 / 35.

[0051] [Photoradical polymerization initiator] Various compounds can be used without particular limitation as the photoradical polymerization initiator contained in the composition of the present invention. Examples of photoradical polymerization initiators include α-carbonyl compounds (US Patent No. 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 No. 3,046,127 and 2,951,758), and combinations of triarylimidazole dimers and p-aminophenyl ketones (US Patent No. 3,549,367 Examples include acridine and phenazine compounds (JP 60-105667 and U.S. Patent No. 4,239850), oxadiazole compounds (U.S. Patent No. 4,212970), o-acyloxime compounds (JP 2016-27384

[0065] ), and acylphosphine oxide compounds (JP 63-40799, JP 5-29234, JP 10-95788 and JP 10-29997). Commercially available photoradical polymerization initiators can also be used, including Irgacure-184, Irgacure-907, Irgacure-369, Irgacure-651, Irgacure-819, Irgacure-OXE-01, and Irgacure-OXE-02 from BASF.

[0052] The photoradical polymerization initiator may be used alone or in combination of two or more. The content of the photoradical polymerization initiator is preferably 0.5 to 25% by mass, and more preferably 1 to 15% by mass, based on the total mass of solids in the composition of the present invention.

[0053] [Solvent] The compositions of the present invention preferably contain a solvent from the viewpoint of workability. Examples of solvents include ketones (e.g., acetone, 2-butanone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone), ethers (e.g., dioxane and tetrahydrofuran), aliphatic hydrocarbons (e.g., hexane), alicyclic hydrocarbons (e.g., cyclohexane), aromatic hydrocarbons (e.g., toluene, xylene, and trimethylbenzene), halogenated carbons (e.g., dichloromethane, dichloroethane, dichlorobenzene, and chlorotoluene), esters (e.g., methyl acetate, ethyl acetate, and butyl acetate), water, alcohols (e.g., ethanol, isopropanol, butanol, and cyclohexanol), cellosolves (e.g., methyl cellosolve and ethyl cellosolve), cellosolve acetates, sulfoxides (e.g., dimethyl sulfoxide), and amides (e.g., dimethylformamide and dimethylacetamide). The solvent may be used alone or in combination of two or more types.

[0054] [Photo-aligned film] The photo-aligned film of the present invention is obtained by curing the above-described photo-aligned film forming composition of the present invention, and is a film having orientation control ability on its surface.

[0055] [Method for producing a photo-alignment film] The method for producing the photo-alignment film of the present invention is not particularly limited, but it can be produced using the composition of the present invention described above. For example, it can be produced by a production method comprising: a coating step of applying the photo-alignment film-forming composition to the surface of a substrate (for example, a cured layer or a transparent support described later) to form a coating film; a heating step of heating and drying the coating film; and a light irradiation step of irradiating the dried coating film with polarized light or unpolarized light from an oblique direction to the surface of the coating film. Each step in the production method will be described in detail below.

[0056] <Coating Process> The coating method in the coating process is not particularly limited and can be appropriately selected according to the purpose. Examples include spin coating, die coating, gravure coating, flexographic printing, and inkjet printing.

[0057] <Heating Process> The temperature of the heating process is not particularly limited as long as it is a temperature at which the solvent contained in the coating film can be dried and removed, but it is preferably 100 to 150°C. The duration of the heating process is not particularly limited as long as it is a time at which the solvent contained in the coating film can be dried and removed, but it is preferably 30 seconds to 5 minutes.

[0058] <Light Irradiation Process> In the light irradiation process, the polarization of light irradiated onto the dried coating film is not particularly limited, and examples include linearly polarized light, circularly polarized light, and elliptically polarized light, with linearly polarized light being preferred. Furthermore, the "oblique direction" for irradiating with unpolarized light is not particularly limited as long as it is a direction tilted at an extreme angle θ (0 < θ < 90°) with respect to the normal direction of the coating film surface, and can be appropriately selected according to the purpose, but θ is preferably 20 to 80°.

[0059] The wavelength for polarized or unpolarized light is not particularly limited as long as it is light that the photo-oriented group is sensitive to, and examples include ultraviolet light, near-ultraviolet light, and visible light, with near-ultraviolet light in the range of 250 to 450 nm being preferred. Examples of light sources for irradiating with polarized or unpolarized light include xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, LED (Light Emitting Diode) lamps, and metal halide lamps. The wavelength range of irradiation can be limited by using interference filters or color filters on ultraviolet or visible light obtained from such light sources. Linear polarization can also be obtained by using polarizing filters or polarizing prisms on light from these light sources.

[0060] The integrated amount of polarized or unpolarized light is not particularly limited, ranging from 1 to 300 mJ / cm². ２ Preferably, 5 to 100 mJ / cm² ２ This is more preferable. The polarized or unpolarized illuminance is not particularly limited, ranging from 0.1 to 300 mW / cm². ２ Preferably, 1 to 100 mW / cm² ２ This is preferable.

[0061] In order to further suppress reflection at the interface with the liquid crystal curing layer, the photo-alignment film of the present invention is preferably subjected to time-of-flight secondary ion mass spectrometry (TOF-SIMS) while irradiating one surface X (hereinafter also referred to as the "air interface side surface") of the photo-alignment film toward the other surface Y (hereinafter also referred to as the "substrate side surface"), and the peak intensity of ion fragments derived from the repeating unit a2 of the photo-aligning polymer A is measured, and it is preferable that the peak intensity Px, which is the peak intensity at a position 50 nm from surface X in the thickness direction of the photo-alignment film, and the peak intensity Py, which is the peak intensity at a position 50 nm from surface Y in the thickness direction of the photo-alignment film, satisfy the following formula (2): 1.5 ≤ (Px / Py) (2)

[0062] <TOF-SIMS> The peak intensity of ion fragments is measured using TOF-SIMS with the following equipment and measurement conditions: • Equipment: TOF-SIMS5 (manufactured by ION-TOF) • Measurement conditions: Bi ３ ＋＋ Primary ions (30 kV, 0.3 pA, 150 μm□), high mass resolution mode, charge correction: 10 eV, low-speed electron gun, depth profiling: Ar gas cluster ion beam (Ar １９００ ＋ (10kV, 3.3nA, 500μm□) • Secondary ion detection mode: negative

[0063] [Optical Laminate] The optical laminate of the present invention is an optical laminate having a cured layer and the photo-alignment film of the present invention.

[0064] [Photo-alignment film] The photo-alignment film of the optical laminate of the present invention is the alignment film of the present invention described above, that is, a film obtained by curing the photo-alignment film forming composition of the present invention described above, and having orientation control ability on its surface. Here, "having orientation control ability" means having the function of aligning the liquid crystal compound placed on the photo-alignment film in a predetermined direction. Furthermore, the thickness of the photo-alignment film is preferably 200 nm to 5 μm, and more preferably 300 nm to 1000 nm.

[0065] [Cured Layer] The cured layer of the optical laminate of the present invention is a cured layer comprising a composition (hereinafter abbreviated as "cured layer forming composition") containing a copolymer C having repeating units c1 represented by the following formula (c1) and repeating units c2 represented by the following formula (c2). It is preferable that the cured layer forming composition does not contain liquid crystal compounds, taking into consideration the distinction between the cured layer and the liquid crystal cured layer described later.

[0066] In the above formula (c1), R １３ X represents a hydrogen atom or a methyl group. ５ represents -O- or -NH-, R １４ R represents a substituent having 1 to 16 carbon atoms. In the above formula (c2), １５ X represents a hydrogen atom or a methyl group. ６ represents -O-, L ４ represents an n+1 valent linking group, where n is an integer from 1 to 3, and P ３ This represents a crosslinking group. However, if n is 2 or 3, multiple P ３ These may be the same or different. １４ The substituents with 1 to 16 carbon atoms represented by are R in formula (b1) above. １１ Examples similar to those explained in [previous section] are also included. Furthermore, L ４ The n+1 valent linking group represented by, and P ３ The crosslinking group represented by is L in formula (a3) ​​above. ２ and P １ The same examples as those explained in [previous section] can be cited.

[0067] The content of repeating units c1 in the copolymer C is not particularly limited, but is preferably 20 to 95% by mass, and more preferably 50 to 90% by mass, relative to the total repeating units of copolymer C. Furthermore, the content of repeating units c2 in the copolymer C is not particularly limited, but is preferably 5 to 80% by mass, and more preferably 10 to 50% by mass, relative to the total repeating units of copolymer C.

[0068] Examples of the repeating unit c1 represented by the above formula (c1) include the repeating units c1-1 to c1-20 described below.

[0069] Examples of repeating units c2 represented by the above formula (c2) include the repeating units c2-1 to c2-48 described below.

[0070] Examples of the copolymer C include combinations of specific examples of the repeating units c1 and c2 exemplified above.

[0071] In the present invention, the weight-average molecular weight of the copolymer C is preferably 5,000 to 50,000, and more preferably 15,000 to 35,000.

[0072] Furthermore, in the present invention, the content of copolymer C is preferably 50 to 99% by mass, and more preferably 80 to 99% by mass, based on the total mass of solids in the hardened layer forming composition.

[0073] The cured layer can be cured by known methods using the cured layer-forming composition described above. In addition to copolymer C described above, the cured layer-forming composition may also contain known materials such as polymerization initiators, polyfunctional monomers, surfactants, adhesion improvers, plasticizers, and solvents.

[0074] [Transparent Support] The optical laminate of the present invention preferably further has a transparent support on the side of the cured layer opposite to the photo-alignment film. That is, the optical laminate of the present invention preferably has a transparent support, a cured layer, and a photo-alignment film in this order. Here, transparent means that the transmittance of visible light is 60% or more. Examples of transparent supports include glass substrates and polymer films. Specific examples of polymers constituting the polymer film include, for example, 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 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 polyamide; 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; or polymers obtained by mixing these polymers. Of these, cellulose polymers (hereinafter also referred to as "cellulose acylates"), represented by triacetylcellulose (TAC), can be preferably used. The support may also be a peelable temporary support.

[0075] [Liquid Crystal Curing Layer] The optical laminate of the present invention preferably further has a liquid crystal curing layer on the side of the photo-alignment film opposite to the curing layer. That is, the optical laminate of the present invention preferably has a curing layer, a photo-alignment film, and a liquid crystal curing layer in this order. Here, the liquid crystal curing layer is a layer in which the orientation state of a liquid crystal composition containing a liquid crystal compound is fixed.

[0076] Liquid crystal compounds can be classified into rod-shaped and disc-shaped types based on their shape. Furthermore, each type has low-molecular-weight and high-molecular-weight varieties. High-molecular-weight compounds generally refer to those with a degree of polymerization of 100 or more (Polymer Physics and Phase Transition Dynamics, by Masao Doi, p. 2, Iwanami Shoten, 1992). In this invention, any type of liquid crystal compound can be used, but rod-shaped or disc-shaped liquid crystal compounds (discotic liquid crystal compounds) are preferred. In addition, from the viewpoint of fixing the orientation state of the liquid crystal composition, it is preferable that the liquid crystal compound has polymerizable groups. Examples of polymerizable groups include (meth)acryloyloxy groups and vinyl groups. By polymerizing such liquid crystal compounds, the orientation of the liquid crystal compound can be fixed. After the liquid crystal compound has been fixed by polymerization, it is no longer necessary for it to exhibit liquid crystal properties.

[0077] As the rod-shaped liquid crystal compound, for example, the one described in claim 1 of Japanese Patent Publication No. 11-513019 or paragraphs

[0026] to

[0098] of Japanese Patent Application Publication No. 2005-289980 is preferred, and as the disc-shaped liquid crystal compound, for example, the one described in paragraphs

[0020] to

[0067] of Japanese Patent Application Publication No. 2007-108732 or paragraphs

[0013] to

[0108] of Japanese Patent Application Publication No. 2010-244038 is preferred.

[0078] As the above-mentioned liquid crystal compound, an inverse wavelength-dispersive liquid crystal compound can be used. Hereinafter, in this specification, an "inverse wavelength-dispersive" liquid crystal compound refers to one in which, when the in-plane retardation (Re) value of a phase difference film made using it is measured at a specific wavelength (visible light range), the Re value becomes equal to or higher as the measured wavelength increases.

[0079] The inverse wavelength dispersive liquid crystal compound is not particularly limited as long as it can form an inverse wavelength dispersive film as described above. Examples include the compound represented by general formula (I) described in Japanese Patent Application Publication No. 2008-297210 (particularly the compound described in paragraphs

[0034] to

[0039] ), the compound represented by general formula (1) described in Japanese Patent Application Publication No. 2010-084032 (particularly the compound described in paragraphs

[0067] to

[0073] ), and the compound represented by general formula (1) described in Japanese Patent Application Publication No. 2016-081035 (particularly the compound described in paragraphs

[0043] to

[0055] ). Furthermore, examples include the compounds described in paragraphs

[0027] to

[0100] of Japanese Patent Publication No. 2011-006360, paragraphs

[0028] to

[0125] of Japanese Patent Publication No. 2011-006361, paragraphs

[0034] to

[0298] of Japanese Patent Publication No. 2012-207765, paragraphs

[0016] to

[0345] of Japanese Patent Publication No. 2012-077055, paragraphs

[0017] to

[0072] of WO12 / 141245, paragraphs

[0021] to

[0088] of WO12 / 147904, and paragraphs

[0028] to

[0115] of WO14 / 147904.

[0080] The liquid crystal cured layer can be cured by known methods using a liquid crystal composition containing a liquid crystal compound. In addition to the liquid crystal compound mentioned above, the liquid crystal composition may also contain known materials such as polymerization initiators, polyfunctional monomers, photoacid generators, orientation control agents (vertical orientation agents, horizontal orientation agents), surfactants, adhesion improvers, plasticizers, and solvents.

[0081] The orientation of the liquid crystal compound in the liquid crystal cured layer may be horizontal, vertical, tilted, or twisted, but it is preferable that the rod-shaped liquid crystal compound is fixed in a twisted state.

[0082] [Photo-Oriented Polymer] The photo-oriented polymer of the present invention is a copolymer having a repeating unit a1 represented by formula (a1), a repeating unit a2 represented by formula (a2), and a repeating unit a3 represented by formula (a3). That is, the photo-oriented polymer of the present invention is the photo-oriented polymer A described in the composition of the present invention described above.

[0083] [Curable Composition] The curable composition of the present invention is a curable composition containing a curable polymer A10, a (meth)acrylate polymer B, and a photoradical polymerization initiator. The curable polymer A10 is a copolymer having repeating units a20 represented by formula (a20), which will be described later, and repeating units a30 represented by formula (a30), which will be described later. The refractive index of a single film of the curable polymer A10 at 589 nm is 1.60 or higher at 23°C, and the refractive index of a single film of the (meth)acrylate polymer B at 589 nm is 1.55 or lower at 23°C. Furthermore, when the surface free energy of the cured product of the curable polymer A10 is SFEA and the surface free energy of the cured product of the (meth)acrylate polymer B is SFEB, the following formula (1) is satisfied. In this invention, if the present invention contains two or more types of at least one of curable polymer A10 and (meth)acrylate polymer B, it is sufficient that the following formula (1) is satisfied in at least one combination of curable polymer A10 and (meth)acrylate polymer B: 5 < SFEB - SFEA < 25 (1)

[0084] In other words, the curable composition of the present invention is the same as the photo-alignment film-forming composition of the present invention described above, except that the photo-alignment polymer A10 described below is added in place of the photo-alignment polymer A contained in the photo-alignment film-forming composition of the present invention described above.

[0085] [Curable Polymer A10] The curable polymer A10 contained in the curable composition of the present invention is a copolymer having a repeating unit a20 represented by the following formula (a20) and a repeating unit a30 represented by the following formula (a30). In addition, the curable polymer A10 may have any repeating units other than the repeating units a20 and a30.

[0086] In the above formula (a20), R １６ X represents a hydrogen atom or a methyl group. ７ represents -O-, -S-, or -NH-, R １７R represents a substituent. However, the refractive index at 589 nm of a single film of the homopolymer having the repeating unit represented by formula (a20) above is 1.68 or higher at 23°C. In formula (a30) above, R １８ X represents a hydrogen atom or a methyl group. ８ represents -O-, -S-, or -NH-, L ５ represents an n+1 valent linking group, where n is an integer from 1 to 3, and P ４ This represents a crosslinking group. However, if n is 2 or 3, multiple P ４ These may be the same or different. １７ The substituent represented by is R in formula (a2) above. ８ Examples similar to those explained in [previous section] are also included. Furthermore, L ５ The n+1 valent linking group represented by, and P ４ The crosslinking group represented by is L in formula (a3) ​​above. ２ and P １ The same examples as those explained in [previous section] can be cited.

[0087] In other words, the curable polymer A10 is the same polymer as the photo-oriented polymer A, except that it does not have the repeating units (a1) that the photo-oriented polymer A contained in the photo-oriented film-forming composition of the present invention has.

[0088] The content of repeating units a20 in the curable polymer A10 is not particularly limited, but is preferably 20 to 95% by mass, and more preferably 40 to 80% by mass, relative to the total repeating units of the curable polymer A10. Furthermore, the content of repeating units a30 in the curable polymer A10 is not particularly limited, but is preferably 5 to 80% by mass, and more preferably 20 to 60% by mass, relative to the total repeating units of the curable polymer A10.

[0089] Examples of repeating units a20 represented by the above formula (a20) include those similar to those described in the above-mentioned photo-oriented polymer (repeating units a2-1 to a2-10).

[0090] Examples of repeating units a30 represented by the above formula (a30) include those similar to those described in the above-mentioned photo-oriented polymer (repeating units a3-1 to a3-60).

[0091] Examples of the curable polymer A10 include combinations of specific examples of the repeating units a20 and a30 exemplified above.

[0092] In the present invention, the weight-average molecular weight of the curable polymer A10 is preferably 30,000 or less, more preferably 3,000 to 30,000, and even more preferably 4,000 to 25,000.

[0093] Furthermore, in the present invention, the content of the curable polymer A10 is preferably 20 to 80% by mass, and more preferably 30 to 60% by mass, based on the total mass of the solid content of the curable composition of the present invention.

[0094] [Refractive Index Gradient Film] The refractive index gradient film of the present invention is a refractive index gradient film obtained by curing the curable composition of the present invention. Here, the refractive index gradient film can be cured using the curable composition described above by a known method. In addition to the curable polymer A10 described above, the curable composition may also contain known materials such as polymerization initiators, polyfunctional monomers, surfactants, adhesion improvers, plasticizers, and solvents.

[0095] 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.

[0096] [Synthesis of photo-oriented polymer A-1]

[0097] Monomer ma1-6 (3.5 g), monomer ma2-1 (5.4 g), and monomer ma3-1Cl (1.1 g) were dissolved in cyclohexanone (18.7 g) and the mixture was heated to 80°C. A 5% by mass solution of polymerization initiator V-601 in cyclohexanone (5 g) was added dropwise to the reaction mixture over 30 minutes, and the mixture was heated to 90°C after addition. After stirring at 90°C for 6 hours, the mixture was cooled to room temperature, triethylamine (6.7 mL) was added, and the mixture was heated to 60°C. After stirring at 60°C for 1 hour, the mixture was cooled to room temperature, and the reaction mixture was added to a methanol / water mixture (v / v = 7 / 3, 500 mL), and the precipitated solid was filtered off. From the obtained solid, a photo-oriented polymer A-1 (6.2 g, weight-average molecular weight: 7000) having repeating units a1-6, a2-1, and a3-1 was obtained by trituration using tetrahydrofuran and methanol.

[0098] [Synthesis of (meth)acrylate polymer B-1]

[0099] Monomer mb1-1 (9.0 g) and monomer mb2-1Cl (1.0 g) were dissolved in cyclohexanone (18.7 g) and the mixture was heated to 100°C. A 13% by mass solution of polymerization initiator V-601 in cyclohexanone (5 g) was added dropwise to the reaction mixture over 30 minutes. After stirring at 100°C for 6 hours, the mixture was cooled to room temperature, triethylamine (6.7 mL) was added, and the mixture was heated to 60°C. After stirring at 60°C for 1 hour, the mixture was cooled to room temperature and the reaction mixture was added to a methanol / water mixture (v / v = 7 / 3, 500 mL). The precipitated solid was filtered off. From the obtained solid, (meth)acrylate polymer B-1 (7.6 g, weight-average molecular weight: 4000) having repeating units b1-1 and b2-1 was obtained by trituration using tetrahydrofuran and methanol.

[0100] [Synthesis of copolymer C-1]

[0101] Monomer mc1-1 (9.0 g) and monomer mc2-1Cl (1.0 g) were dissolved in cyclohexanone (35.0 g) and the mixture was heated to 80°C. A 20% by mass solution of polymerization initiator V-601 in cyclohexanone (5 g) was added dropwise to the reaction mixture over 30 minutes. After stirring at 80°C for 6 hours, the mixture was cooled to room temperature, triethylamine (6.7 mL) was added, and the mixture was heated to 60°C. After stirring at 60°C for 1 hour, the mixture was cooled to room temperature, and the reaction mixture was added to a methanol / water mixture (v / v = 7 / 3, 500 mL). The precipitated solid was filtered off. Copolymer C-1 (6.9 g, weight-average molecular weight: 25000) having repeating units c1-1 and c2-1 was obtained from the obtained solid by trituration using tetrahydrofuran and methanol.

[0102] [Example 1] A solution prepared by mixing the copolymer C-1, the photopolymerization initiator S-1, and methyl ethyl ketone in a mass ratio of 148 / 2 / 2850 was applied to a PET film (100 μm thick, manufactured by Toyobo Co., Ltd., Cosmoshine A4265) using a bar coater. After natural drying, the film was irradiated with an ultraviolet lamp at a dose of 500 mJ / cm². ２ The material was cured to form a cured layer (500 nm thick). Next, a solution obtained by mixing the above photo-oriented polymer A-1, the above (meth)acrylate polymer B-1, the following photopolymerization initiator S-1, and methyl ethyl ketone in a mass ratio of 45 / 50 / 5 / 1900 was applied to the cured layer using a bar coater, dried at 80°C for 1 hour, and then irradiated with an ultraviolet lamp equipped with a 313 nm cut filter at a dose of 500 mJ / cm². ２ By curing with [a specific method], a photo-alignment film precursor was formed before the ability to control orientation was imparted. Next, the photo-alignment film precursor was irradiated with an irradiation dose of 7.9 mJ / cm². ２ By irradiating the photo-alignment film precursor with linearly polarized ultraviolet light (wavelength 313 nm), a photo-alignment film (thickness 500 nm) was formed, and an optical laminate F-1 (PET film / cured layer / photo-alignment film) was obtained.

[0103] Polymerization initiator S-1

[0104] [Examples 2-14 and Comparative Examples 1-3] Optical laminates F-2 to F-14 and optical laminates HF-1 to HF-3 can be obtained in the same manner as optical laminate F-1, except that various polymers with the repeating units and weight-average molecular weights listed in Table 1 below are used instead of the photo-aligning polymer A-1 and (meth)acrylate polymer B-1 used for forming the photo-alignment film, and copolymer C-1 used for forming the cured layer, and additives are added as desired.

[0105]

[0106] The structural formulas of the photo-oriented polymers A-1 to A-6, (meth)acrylate polymers B-1 and B-2, copolymers C-1 and C-2, and siloxane 1 and additive 1, as described in Table 1 above, are shown below.

[0107] Photo-oriented polymer A-1

[0108] Photo-oriented polymer A-2

[0109] Photo-oriented polymer A-3

[0110] Photo-oriented polymer A-4

[0111] Photo-oriented polymer A-5

[0112] Photo-oriented polymer A-6

[0113] (Meth)acrylate polymer B-1

[0114] (Meth)acrylate polymer B-2

[0115] Copolymer C-1

[0116] Copolymer C-2

[0117] Additive 1

[0118] Siloxane 1

[0119] PMAA

[0120] [Example 15 and Comparative Examples 4-5] Optical laminates F10-1 and HF10-1 to HF10-2 can be obtained in the same manner as optical laminate F-1, except that various polymers with the repeating units and weight-average molecular weights listed in Table 2 below are used.

[0121]

[0122] The structural formula of the curable polymer A10-1, as described in Table 2 above, is shown below.

[0123] Curable polymer A10-1

[0124] [Refractive Index of Homopolymers] The refractive index (n) at 589 nm of a single film of homopolymer having the following repeating units is as follows at 23°C: a2-1: n = 1.69 a2-2: n = 1.69 a2-3: n = 1.71 a2-4: n = 1.75 a2-5: n = 1.75

[0125] [Evaluation Item 1: Orientation] [Preparation of Coating Solution for Reflective Layer] <Coating Solution for Reflective Layer R-1> The following composition was stirred and dissolved in a container kept at 70°C to prepare the coating solution for the reflective layer R-1. Here, R represents a coating solution using a rod-shaped liquid crystal compound. ------------------------------------------------------------------- Coating Solution for Reflective Layer R-1 ------------------------------------------------------------------- ・Methyl ethyl ketone 120.9 parts by mass ・Cyclohexanone 21.3 parts by mass ・Mixture X of the following rod-shaped liquid crystal compounds 100.0 parts by mass ・Photopolymerization initiator B 3.00 parts by mass ・Chiral agent A 3.63 parts by mass ・Surfactant S1 0.1 parts by mass -------------------------------------------------------------------

[0126] Mixture X of rod-shaped liquid crystal compounds [a mixture of the following liquid crystal compounds (RA), (RB), and (RC) in a mass ratio of 84:14:2]

[0127] Chiral agent A

[0128] Surfactant S1

[0129] Photopolymerization initiator B

[0130] The optical laminates prepared in Examples 1-14 and Comparative Examples 1-3 were coated with reflective layer coating solution R-1 using a bar coater and dried at 100°C for 72 seconds. Subsequently, under a low-oxygen atmosphere (100 ppm or less), the surface was coated at 70°C with an illuminance of 100 mW / cm². ２ , irradiation amount 100mJ / cm ２ The material was cured by irradiation with light from a high-pressure mercury lamp. This formed a first blue light reflective layer (first layer) consisting of a cholesteric liquid crystal layer. The resulting cured film was punched out to 40 mm x 40 mm to create a coating sample. In all cases, the light irradiation was performed from the cholesteric liquid crystal layer side. The coating thickness was adjusted so that the film thickness of the first blue light reflective layer after curing was 1.7 μm.

[0131] The prepared samples were measured for reflectance according to the measurement methods described below and evaluated according to the following criteria. The results are shown in Table 3 below. If the evaluation is A or B, it can be evaluated that the orientation of the liquid crystal cured layer by the photoalignment film is good. Measurement method: UV-vis Instrument: V-750 spectrometer manufactured by JASCO Corporation (light source: deuterium lamp / halogen lamp) Measurement conditions: 25℃, 60%RH Evaluation method: Light was incident from the coated surface side, the reflectance was measured, and the maximum value (λmax) of the average reflectance of S-polarized and P-polarized light was taken as the reflectance. <Evaluation criteria> A: Reflectance of 35% or more B: Reflectance of 25% or more and less than 35% C: Reflectance less than 25%

[0132] [Evaluation Item 2: Gradient of Refractive Index of Photo-Alignment Film and Refractive Index Gradient Film] The photo-alignment film and refractive index gradient film of the optical laminates prepared in the examples and comparative examples were analyzed by TOF-SIMS using the method described above. The ratio (Px / Py) of Px, which is the peak intensity at a position of 50 nm in the thickness direction of the photo-alignment film and refractive index gradient film from the surface X (air interface side surface), and Py, which is the peak intensity at a position of 50 nm in the thickness direction of the photo-alignment film and refractive index gradient film from the surface Y (hardened layer side surface), was calculated and evaluated according to the following criteria. The results are shown in Tables 3 and 4 below. If the evaluation is A to C, it can be evaluated that reflection at the interface with the liquid crystal hardened layer is suppressed. <Evaluation Criteria> A: Ratio (Px / Py) is 10 or more. B: Ratio (Px / Py) is 4 or more and less than 10. C: Ratio (Px / Py) is 1.5 or more and less than 4. D: Ratio (Px / Py) is 0 or more and less than 1.5.

[0133] [Evaluation Item 3: Haze Degree] The photo-alignment film and refractive index gradient film of the optical laminates prepared in the examples and comparative examples were measured for transmittance at 600 nm using a spectrophotometer, and the haze degree was evaluated according to the following criteria. The results are shown in Tables 3 and 4 below. <Evaluation Criteria> A: Transmittance of 85% or more B: Transmittance of 50% or more and less than 85% C: Transmittance of less than 50%

[0134]

[0135]

[0136] As shown in Tables 1 to 4 above, it was found that when (meth)acrylate polymer B is not incorporated, reflection at the interface with the liquid crystal cured layer cannot be suppressed (Comparative Example 3). Furthermore, even when (meth)acrylate polymer B is incorporated, it was found that the transmittance becomes low if the surface free energy (SFEA) of the cured product of photo-oriented polymer A or curable polymer A10 and the surface free energy (SFEB) of (meth)acrylate polymer B do not satisfy the following formula (1) (Comparative Examples 1-2, 4-5): 5 < SFEB - SFEA < 25 (1)

[0137] In contrast, it was found that when (meth)acrylate polymer B is incorporated, and the surface free energy (SFEA) of the cured product of photo-aligning polymer A or curable polymer A10 and the surface free energy (SFEB) of (meth)acrylate polymer B satisfy formula (1) above, reflection at the interface with the liquid crystal cured layer can be suppressed and a photo-aligned film with high transmittance can be formed (Examples 1 to 15).

Claims

1. A composition for forming an optical alignment film, comprising an optically anisotropic polymer A, a (meth)acrylate polymer B, and a photo-radical polymerization initiator, wherein the optically anisotropic polymer A is a copolymer having a repeating unit a1 represented by the following formula (a1), a repeating unit a2 represented by the following formula (a2), and a repeating unit a3 represented by the following formula (a3); the refractive index of the single film of the optically anisotropic polymer A at 589 nm is 1.60 or more at 23°C; the refractive index of the single film of the (meth)acrylate polymer B at 589 nm is 1.55 or less at 23°C; and when the surface free energy of the cured product of the optically anisotropic polymer A is represented by SFEA and the surface free energy of the cured product of the (meth)acrylate polymer B is represented by SFEB, the following formula (1) is satisfied. 5 < SFEB - SFEA < 25 (1) Here, in the formulas (a1) to (a3), １ R represents a hydrogen atom or a methyl group. L １ represents a divalent linking group. R ２ to R ６ each independently represents a hydrogen atom or a substituent. R ７ represents a hydrogen atom or a methyl group. X １ represents -O-, -S-, or -NH-. R ８ represents a substituent. However, the refractive index of the single film of the homopolymer having the repeating unit represented by the formula (a2) at 589 nm is 1.68 or more at 23°C. R ９ represents a hydrogen atom or a methyl group. X ２ represents -O-, -S-, or -NH-. L ２ represents an n + 1-valent linking group. n represents an integer of 1 to 3. P １ represents a crosslinkable group. However, when n is 2 or 3, the plurality of P １ may be the same or different from each other.

2. L in formula (a1) １ However, the following formula (L １ -1) to (L １ The photo-alignment film-forming composition according to claim 1, which represents any of the divalent linking groups in -11). Here, the above formula (L １ -1) to (L １ -11) In this formula, *1 represents the bond position with the main chain in formula (a1), and *2 represents the bond position with the carbon atom of the carbonyl group.

3. R ​​in formula (a2) ８ The photo-alignment film-forming composition according to claim 1, wherein the substituent comprises at least one selected from the group consisting of a sulfur atom, an iodine atom, a bromine atom, and a naphthalene ring.

4. The photo-alignment film forming composition according to claim 1, wherein the repeating unit a2 represents any of the following repeating units (a2-1) to (a2-5). Here, in the above equations (a2-1) to (a2-5), R ７ represents a hydrogen atom or a methyl group.

5. The photo-alignment film-forming composition according to claim 1, wherein the (meth)acrylate polymer B is a copolymer having a repeating unit b1 represented by the following formula (b1) and a repeating unit b2 represented by the following formula (b2). Here, in equations (b1) and (b2), R １０ X represents a hydrogen atom or a methyl group. ３ This represents -O- or -NH-. １１ R represents a substituent with 1 to 16 carbon atoms. １２ X represents a hydrogen atom or a methyl group. ４ This represents -O-. ３ represents an n+1 valence linking group. n represents an integer from 1 to 3. P ２ This represents a crosslinking group. However, if n is 2 or 3, multiple P ２ These may be the same or different.

6. The photo-alignment film-forming composition according to claim 1, wherein the ratio of the content of the (meth)acrylate polymer B to the content of the photo-aligning polymer A is 30 / 70 to 70 / 30.

7. The photo-alignment film-forming composition according to claim 1, wherein the weight-average molecular weight of the photo-aligning polymer A is 30,000 or less, and the weight-average molecular weight of the (meth)acrylate polymer B is 10,000 or less.

8. A photo-alignment film obtained by curing a photo-alignment film-forming composition according to any one of claims 1 to 7, having orientation control capability on its surface.

9. The photo-alignment film according to claim 8, wherein when an ion beam is irradiated from one surface X to the other surface Y of the photo-alignment film and a time-of-flight secondary ion mass spectrometry is performed, and the peak intensity of ion fragments derived from the repeating unit a2 of the photo-aligning polymer A according to claim 1 is measured, the peak intensity Px, which is the peak intensity at a position 50 nm from surface X in the thickness direction of the photo-alignment film, and the peak intensity Py, which is the peak intensity at a position 50 nm from surface Y in the thickness direction of the photo-alignment film, satisfy the following formula (2): 1.5 ≤ (Px / Py) (2) 10. An optical laminate having a cured layer and a photo-alignment film according to claim 8, wherein the cured layer includes a cured product of a composition containing a copolymer C having repeating units c1 represented by the following formula (c1) and repeating units c2 represented by the following formula (c2). Here, in equations (c1) and (c2), R １３ X represents a hydrogen atom or a methyl group. ５ This represents -O- or -NH-. １４ R represents a substituent with 1 to 16 carbon atoms. １５ X represents a hydrogen atom or a methyl group. ６ This represents -O-. ４ represents an n+1 valence linking group. n represents an integer from 1 to 3. P ３ This represents a crosslinking group. However, if n is 2 or 3, multiple P ３ These may be the same or different.

11. The optical laminate according to claim 10, further comprising a transparent support on the side of the cured layer opposite to the photo-alignment film.

12. The optical laminate according to claim 10, further comprising a liquid crystal curing layer on the side of the photo-alignment film opposite to the cured layer.

13. The optical laminate according to claim 10, wherein the thickness of the photo-alignment film is 200 nm to 5 μm.

14. A photo-oriented polymer having a repeating unit a1 represented by the following formula (a1), a repeating unit a2 represented by the following formula (a2), and a repeating unit a3 represented by the following formula (a3). Here, in equations (a1) to (a3) ​​above, R １ L represents a hydrogen atom or a methyl group. １ R represents a divalent linking group. ２ ~R ６ Each of these independently represents a hydrogen atom or a substituent. ７ X represents a hydrogen atom or a methyl group. １ This represents -O-, -S-, or -NH-. ８ R represents a substituent. However, the refractive index at 589 nm of a single film of the homopolymer having the repeating unit represented by formula (a2) is 1.68 or higher at 23°C. ９ X represents a hydrogen atom or a methyl group. ２ This represents -O-, -S-, or -NH-. ２ represents an n+1 valence linking group. n represents an integer from 1 to 3. P １ This represents a crosslinking group. However, if n is 2 or 3, multiple P １ These may be the same or different.

15. A curable composition comprising a curable polymer A10, a (meth)acrylate polymer B, and a photoradical polymerization initiator, wherein the curable polymer A10 is a copolymer having repeating units a20 represented by the following formula (a20) and repeating units a30 represented by the following formula (a30), the refractive index of a single film of the curable polymer A10 at 589 nm is 1.60 or higher at 23°C, the refractive index of a single film of the (meth)acrylate polymer B at 589 nm is 1.55 or lower at 23°C, and when the surface free energy of the cured product of the curable polymer A10 is SFEA and the surface free energy of the cured product of the (meth)acrylate polymer B is SFEB, the curable composition satisfies the following formula (1): 5 < SFEB - SFEA < 25 (1) Here, in formulas (a20) and (a30), R １６ X represents a hydrogen atom or a methyl group. ７ This represents -O-, -S-, or -NH-. １７ R represents a substituent. However, the refractive index at 589 nm of a single film of the homopolymer having the repeating unit represented by formula (a20) is 1.68 or higher at 23°C. １８ X represents a hydrogen atom or a methyl group. ８ This represents -O-, -S-, or -NH-. ５ represents an n+1 valence linking group. n represents an integer from 1 to 3. P ４ This represents a crosslinking group. However, if n is 2 or 3, multiple P ４ These may be the same or different.

16. A refractive index gradient film obtained by curing the curable composition according to claim 15.

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