Optical film and display device

Abstract

The present invention provides: an optical film having excellent adhesion between a cellulose acylate film and a resin layer containing polyvinyl alcohol resin; and a display device including the optical film. In this optical film, a cellulose acylate film, a layer formed from a composition containing a compound having a boronic acid structure and a surfactant, a resin layer containing polyvinyl alcohol resin, and a liquid crystal layer are directly laminated in this order.

Description

Optical film, display device

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

[0002] As a liquid crystal layer formed using a liquid crystal compound, a light absorption anisotropic layer, an optical anisotropic layer, etc. are known, and these liquid crystal layers are applied in various fields such as the display field. For example, in Patent Document 1, an optical film having a light absorption anisotropic layer containing a dichroic dye compound is disclosed. [[ID=۸]]

[0003] International Publication No. 2022 / 158517

[0004] In Patent Document 1, an optical film having a cellulose acylate film, a resin layer containing a polyvinyl alcohol-based resin, and a light absorption anisotropic layer in this order is specifically disclosed. In the above optical film, in order to enhance the adhesion between the cellulose acylate film and the resin layer containing a polyvinyl alcohol-based resin, a treatment of saponifying the surface of the cellulose acylate film with an alkaline solution is disclosed. On the other hand, recently, it has been desired to enhance the adhesion between a cellulose acylate film and a resin layer containing a polyvinyl alcohol-based resin by a method other than the method of subjecting the cellulose acylate film to a saponification treatment as described above.

[0005] An object of the present invention is to provide an optical film having excellent adhesion between a cellulose acylate film and a resin layer containing a polyvinyl alcohol-based resin. Another object of the present invention is also to provide a display device including the above optical film.

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

[0007] (1) An optical film in which a layer formed from a composition comprising a cellulose acylate film, a compound having a boronic acid structure, and a surfactant, a resin layer comprising a polyvinyl alcohol-based resin, and a liquid crystal layer are directly laminated in this order. (2) The optical film according to (1), wherein the composition further comprises a compound selected from the group consisting of polyfunctional acrylates and polyfunctional methacrylates. (3) The optical film according to (2), wherein the acrylic equivalent of the polyfunctional acrylate and the methacrylic equivalent of the polyfunctional methacrylate are each 150 g / eq. or less. (4) The optical film according to any one of (1) to (3), wherein the surfactant has a hydrophilic group. (5) The optical film according to any one of (1) to (4), wherein the molecular weight of the compound having a boronic acid structure is 400 or less. (6) The optical film according to (5), wherein the molecular weight of the compound having a boronic acid structure is 300 or less. (7) The optical film according to any one of (1) to (6), wherein the content of the compound having a boronic acid structure is 10 to 40% by mass with respect to the total solid content of the composition. (8) The optical film according to (7), wherein the content of the compound having a boronic acid structure is 15 to 35% by mass with respect to the total solid content of the composition. (9) The optical film according to any one of (1) to (8), wherein the thickness of the layer formed from the composition is 3.0 μm or less. (10) The optical film according to any one of (1) to (9), wherein the liquid crystal layer has a protective layer on the side opposite to the resin layer containing a polyvinyl alcohol-based resin, the liquid crystal layer and the protective layer are directly laminated, and the protective layer is a layer formed from a protective layer-forming composition containing a compound selected from the group consisting of polyfunctional acrylates and polyfunctional methacrylates. (11) The optical film according to (10), wherein the acrylic equivalent of the polyfunctional acrylate and the methacrylic equivalent of the polyfunctional methacrylate contained in the protective layer-forming composition are each 150 g / eq. or less. (12) The optical film according to (10), wherein the viscosity of the polyfunctional acrylate and polyfunctional methacrylate contained in the protective layer-forming composition is 10,000 mPa·s or more at 25°C. (13) The optical film according to (10), wherein the molecular weight of the polyfunctional acrylate and polyfunctional methacrylate contained in the protective layer-forming composition is 2,000 or less.(14) An optical film according to any one of (1) to (13), wherein the liquid crystal layer is a light-absorbing anisotropic layer containing a dichroic substance. (15) An optical film according to (14), wherein the angle between the transmittance center axis of the light-absorbing anisotropic layer and the normal direction of the surface of the light-absorbing anisotropic layer is 0 to 45°. (16) A display device comprising the optical film according to any one of (1) to (15).

[0008] According to the present invention, an optical film can be provided that exhibits excellent adhesion between a cellulose acylate film and a resin layer containing a polyvinyl alcohol-based resin. Furthermore, according to the present invention, a display device containing the above optical film can be provided.

[0009] This figure conceptually illustrates an example of the optical film of the present invention.

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

[0011] In this specification, "in-plane lagging axis" means the direction in which the refractive index is maximum.

[0012] Furthermore, 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. In this invention, Re(λ) and Rth(λ) are values ​​measured at wavelength λ using AxoScan (manufactured by Axometrics). 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).

[0013] Furthermore, 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).

[0014] Furthermore, in this specification, "(meth)acrylate" refers to "acrylate" or "methacrylate," "(meth)acrylic" refers to "acrylic" or "methacrylic," and "(meth)acryloyl" refers to "acryloyl" or "methacryloyl."

[0015] Furthermore, in this specification, "solids" of a composition means the components that form the layer formed using the composition, and if the composition contains a solvent (organic solvent, water, etc.), it means all components excluding the solvent. In addition, liquid components that form a layer are also considered to be solids.

[0016] A key feature of the optical film of the present invention is the provision of a layer (hereinafter also simply referred to as the "specific layer") formed from a composition containing a compound having a boronic acid structure and a surfactant, between the cellulose acylate film and the resin layer containing the polyvinyl alcohol-based resin. In the specific layer, the inclusion of a compound having a boronic acid structure causes bonding between the compound having a boronic acid structure in the specific layer and the polyvinyl alcohol-based resin in the resin layer containing the polyvinyl alcohol-based resin, improving the adhesion between the two films. As a result, the adhesion between the cellulose acylate film and the resin layer containing the polyvinyl alcohol-based resin is considered to be improved.

[0017] Figure 1 shows an example of the optical film of the present invention. As shown in Figure 1, the optical film 10 has a cellulose acylate film 12, a specific layer 14, a resin layer 16 containing a polyvinyl alcohol-based resin, and a liquid crystal layer 18 in this order. As shown in Figure 1, the cellulose acylate film 12 and the specific layer 14 are in direct contact, the specific layer 14 and the resin layer 16 containing a polyvinyl alcohol-based resin are in direct contact, and the resin layer 16 containing a polyvinyl alcohol-based resin and the liquid crystal layer 18 are in direct contact. In other words, in the optical film 10, the cellulose acylate film 12, the specific layer 14, the resin layer 16 containing a polyvinyl alcohol-based resin, and the liquid crystal layer 18 are directly laminated. The individual components included in the optical film 10 will be described in detail below.

[0018] <Cellulose Acylate Film> A cellulose acylate film is a film containing cellulose acylate. Cellulose acylate is obtained by acyling the hydroxyl group of cellulose, and the substituent can be any acetyl group with 2 carbon atoms to one with 22 carbon atoms. The acyl group with 2 to 22 carbon atoms that substitutes for the hydroxyl group of cellulose is not particularly limited and may be an aliphatic group or an aromatic group. Examples of cellulose acylates substituted with these groups include alkyl carbonyl esters of cellulose, alkenyl carbonyl esters of cellulose, aromatic carbonyl esters of cellulose, and aromatic alkyl carbonyl esters of cellulose. The acyl group is preferably an acetyl group, propionyl group, butanoyl group, benzoyl group, naphthylcarbonyl group, or cinnamoyl group, with acetyl group or propionyl group being more preferred.

[0019] In cellulose acylates, there are no particular restrictions on the degree of acyl substitution of the hydroxyl groups of cellulose, however, a higher degree of acyl substitution is preferable because it allows for better compatibility with various additives. For this reason, the degree of acyl substitution (total substitution) of the hydroxyl groups of cellulose is preferably 2.50 to 3.00, more preferably 2.70 to 2.96, and even more preferably 2.80 to 2.95. Furthermore, when only acetyl groups are substituted in cellulose acylates, the degree of substitution of the acetyl groups is preferably 2.70 to 2.96, and more preferably 2.80 to 2.95. Methods for measuring the degree of substitution (acyl substitution) of acetic acid and / or fatty acids having 3 to 22 carbon atoms that substitute for the hydroxyl groups of cellulose in cellulose acylates include methods according to ASTM D-817-91 and NMR (nuclear magnetic resonance) spectroscopy.

[0020] Cellulose acylate films may contain additives. Examples of additives include plasticizers, hydrophobic agents, ultraviolet absorbers, and retardation modifiers. More specific examples of additives include polyester oligomers, sugar ester compounds, and phosphate ester compounds. The content of additives in the cellulose acylate film (total content if multiple additives are included) is preferably 1 to 20% by mass relative to the total mass of cellulose acylate.

[0021] As the cellulose acylate film, cellulose triacetate film is preferred.

[0022] The in-plane retardation Re(550) of the cellulose acylate film at a wavelength of 550 nm is not particularly limited, but is preferably 10 nm or less, and more preferably 5 nm or less. The lower limit is not particularly limited, but 0 nm is an example. The retardation Rth(550) in the thickness direction of the cellulose acylate film at a wavelength of 550 nm is not particularly limited, but is preferably -40 to 40 nm.

[0023] The thickness of the cellulose acylate film is not particularly limited, but 20 to 100 μm is preferred.

[0024] <Specific Layer> The specific layer is a layer formed from a composition containing compounds having a boronic acid structure and surfactants. Below, we will first describe in detail each component contained in the composition.

[0025] (Compounds containing a boronic acid structure) An example of a boronic acid structure found in compounds containing a boronic acid structure is the structure represented by formula (X). * indicates the bond position.

[0026]

[0027] In formula (X), R 1 and R 2 Each of these independently represents a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, an optionally substituted aromatic ring group, or an optionally substituted aliphatic heterocyclic group. The aliphatic hydrocarbon group may be linear, branched, or cyclic. The number of carbon atoms in the aliphatic hydrocarbon group is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 5. Examples of aliphatic hydrocarbon groups include alkyl groups, alkenyl groups, and alkynyl groups. Examples of aromatic ring groups include aromatic hydrocarbon groups and aromatic heterocyclic groups. Examples of aromatic hydrocarbon groups include phenyl groups and naphthyl groups. Examples of aromatic heterocyclic groups include pyridyl groups, imidazolyl groups, and furyl groups. 1 and R 2 They may be connected to each other to form a ring, for example, R 1 and R 2 The isopropyl group may be linked to form a 4,4,5,5-tetramethyl-1,3,2-dioxaborolane ring. In formula (1), R 1 and R 2As for this, a hydrogen atom, or a linear or branched alkyl group having 1 to 3 carbon atoms is preferable, and a hydrogen atom is more preferable. The types of substituents that the aliphatic hydrocarbon group, the aromatic ring group, and the aliphatic heterocyclic group may have are not particularly limited, and known substituents can be mentioned. More specifically, a halogen atom, an alkoxy group, an alkylthio group, an amino group, a cyano group, an alkyl group, and an aryl group can be mentioned. In formula (1), * indicates the bonding position. The number of the boronic acid structures represented by formula (1) that the compound having a boronic acid structure has is not particularly limited, and it may be one or a plurality (two or more).

[0028] The compound having a boronic acid structure is preferable in that the adhesion between the cellulose acylate film and the resin layer containing a polyvinyl alcohol-based resin is more excellent (hereinafter, also simply referred to as "the point where the effect of the present invention is more excellent"). It is preferable to have a polymerizable group. The type of the polymerizable group is not particularly limited, and examples thereof include a radical polymerizable group and a cationic polymerizable group. Examples of the radical polymerizable group include a (meth)acryloyl group, an acrylamide group, a vinyl group, a styryl group, and an allyl group. Examples of the cationic polymerizable group include a vinyl ether group, an oxiranyl group, and an oxetanyl group. Among them, a (meth)acryloyl group, a styryl group, a vinyl group, an oxiranyl group or an oxetanyl group is preferable, a (meth)acryloyl group or a styryl group is more preferable, and a (meth)acryloyl group is particularly preferable. The number of the polymerizable groups is not particularly limited, and it may be one or a plurality (two or more).

[0029] As the compound having a boronic acid structure, the compound represented by formula (1) is preferable in that the effect of the present invention is more excellent.

[0030]

[0031] R in formula (1) 1 and R 2 are defined as described above. Z represents a polymerizable group. The definition of the polymerizable group is as described above. L represents a single bond or a divalent linking group. Examples of the divalent linking group include -O-, -CO-, -NR 3 -, -CO-NR3 Examples include -, -COO-, -O-COO-, alkylene groups (preferably with 1 to 10 carbon atoms, more preferably with 1 to 6 carbon atoms), arylene groups, heteroarylene groups, and divalent linking groups selected from combinations thereof. 3 represents a hydrogen atom or an alkyl group. Arylene groups and heteroarylene groups may have substituents. Examples of substituents include alkyl groups. Combinations include -O-alkylene group-arylene group- and -O-alkylene group-(L 1 -L 2 ) n - is one example. L 1 -O-, -CO-, -NR 3 -, -CO-NR 3 It represents -, -COO-, -O-COO-, -O-CH2-, or -OCH2CH2O-. 2 L represents an optionally substituted arylene group, or an optionally substituted heteroarylene group. 2 A phenylene group, which may have substituents, is preferred. n represents an integer of 1 or more, preferably an integer from 1 to 10, and more preferably an integer from 1 to 5.

[0032] The molecular weight of compounds having a boronic acid structure is not particularly limited, and is often 1000 or less. However, for superior effects of the present invention, it is preferably 400 or less, and more preferably 300 or less. The lower limit is not particularly limited, but is often 100 or more.

[0033] Examples of compounds having a boronic acid structure include the following:

[0034]

[0035]

[0036] The content of compounds having a boronic acid structure in the composition is not particularly limited, but in terms of achieving superior effects of the present invention and superior orientation of the liquid crystal layer, it is preferably 1 to 60% by mass, more preferably 10 to 40% by mass, and even more preferably 15 to 35% by mass, relative to the total solid content of the composition.

[0037] (Surfactant) The composition contains a surfactant. The surfactant may be a low molecular weight compound or a high molecular weight compound. A high molecular weight compound is a compound that contains multiple predetermined repeating units.

[0038] The surfactant preferably has a hydrophobic group. In particular, the surfactant preferably contains a repeating unit having a hydrophobic group. Furthermore, in terms of achieving superior effects of the present invention, the surfactant preferably contains a repeating unit A comprising two or more groups represented by formula (Ia), a linear silicone group, a hydrocarbon group having 10 or more carbon atoms and having two or more terminal methyl groups, or a fluoroalkyl group.

[0039] One aspect of repeating unit A is a repeating unit that includes two or more bases represented by formula (Ia).

[0040]

[0041] In the above formula (Ia), * represents the bond position. 4 , R 5 , and, R 6 Each of these independently represents an alkyl group, an alkenyl group, or an aryl group, which may have substituents. Examples of the alkyl group include linear alkyl groups having 1 to 18 carbon atoms, and branched or cyclic alkyl groups having 3 to 18 carbon atoms. Specifically, examples include methyl, ethyl, propyl, butyl, isopropyl, tert-butyl, and cyclohexyl groups. Examples of the alkenyl group include alkenyl groups having 2 to 12 carbon atoms. Examples of the aryl group include aryl groups having 6 to 12 carbon atoms. Furthermore, preferred substituents that the alkyl group may have include alkyl groups, alkylcarbonyl groups, alkyloxycarbonyl groups, alkylcarbonyloxy groups, or alkoxy groups. 4 , R 5 , and, R 6 Preferably, all of them are alkyl groups.

[0042] One embodiment of repeating unit A is a repeating unit containing a linear silicone group. Here, a suitable example of the linear silicone group is the group represented by the following formula (Ib).

[0043]

[0044] In the above formula (Ib), * represents the joining position. n represents an integer between 11 and 130. 4 , R 5 , R 6 , R 10 , and, R 11 Each of these independently represents an alkyl group, alkenyl group, or aryl group, which may have substituents. 10 These may be the same or different, and there may be multiple R 11 These may be the same or different.

[0045] In the above formula (Ib), n represents an integer from 3 to 130, preferably from 5 to 70, and more preferably from 7 to 65. Also, in the above formula (Ib), R 4 , R 5 , R 6 , R 10 , and, R 11 Preferred embodiments of each group represented by the above formula (Ia) include R 4 , R 5 , and, R 6 This is similar to the preferred embodiments of each group described in [reference].

[0046] One embodiment of repeating unit A is a repeating unit comprising a hydrocarbon group having 10 or more carbon atoms and having two or more terminal methyl groups. Here, "terminal methyl group" means a methyl group that constitutes the end of the linear or side chain of the hydrocarbon group. For example, linear alkyl groups such as n-propyl and n-butyl groups are alkyl groups having one terminal methyl group, isopropyl groups are alkyl groups having two terminal methyl groups, and t-butyl groups are alkyl groups having three terminal methyl groups. For example, n-decane groups have 10 carbon atoms and are alkyl groups having one terminal methyl group, but any of the groups represented by formulas (a-1) to (a-4) below all have 10 or more carbon atoms and have two or more terminal methyl groups (methyl groups enclosed by dotted lines in the formulas below). The number of terminal methyl groups is two or more, preferably three or more, and more preferably three to ten.

[0047]

[0048] As hydrocarbon groups having 10 or more carbon atoms and having two or more terminal methyl groups, hydrocarbon groups having 10 to 20 carbon atoms are preferred, alkyl groups having 10 to 20 carbon atoms are more preferred, linear alkyl groups having 10 to 18 carbon atoms, branched alkyl groups having 10 to 18 carbon atoms are even more preferred, and branched alkyl groups having 10 to 18 carbon atoms are particularly preferred.

[0049] One embodiment of repeating unit A is a repeating unit containing a fluoroalkyl group. The fluoroalkyl group is an alkyl group having a fluorine atom, in which some or all of the hydrogen atoms in the alkyl group are substituted with fluorine atoms. A group represented by formula (Ic) is preferred as the fluoroalkyl group. Formula (Ic) *-(CF2) m -R 12 R 12 represents a hydrogen atom or a fluorine atom. m represents an integer of 2 or more. m is preferably an integer of 4 or more, and preferably an integer of 20 or less.

[0050] As the repeating unit A, the repeating unit represented by formula (A) is preferred because it exhibits superior effects compared to the present invention.

[0051]

[0052] In the above formula (A), R 1a and R 2a Each of these independently represents either a hydrogen atom or an alkyl group. 3a L represents a hydrogen atom or substituent. 1a is -O- or -NR 5a - represents R 5a L represents a hydrogen atom or a substituent. Alkyl alkyl groups are preferred as substituents. 2a represents a single bond or a divalent linking group. Examples of divalent linking groups include alkylene groups (preferably with 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms), -arylene groups, -CO-, -O-, -S-, -C(=S)-, and -NR 6a -, and combinations of two or more of these. R 6a R represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms. 4ａ This represents a group containing two or more groups represented by formula (Ia), a linear silicone group, a hydrocarbon group having 10 or more carbon atoms and having two or more terminal methyl groups, or a fluoroalkyl group. The definitions of each group are as described above.

[0053] Repeating unit A may be used alone or in combination of two or more types. The content of repeating unit A is preferably 20% by mass or more, and more preferably 30% by mass or more, relative to the total repeating units of the surfactant. Furthermore, the content of repeating unit A is preferably 90% by mass or less, more preferably 70% by mass or less, and even more preferably 50% by mass or less, relative to the total repeating units of the surfactant.

[0054] The surfactant preferably has a hydrophilic group. The surfactant in a specific layer tends to be unevenly distributed on the resin layer side of that layer. Therefore, when the surfactant has a hydrophilic group, the boronic acid structure exhibits hydrophilicity, and as a result, compounds having a boronic acid structure also tend to be unevenly distributed on the resin layer side of that layer. In other words, as the surfactant becomes unevenly distributed, compounds having a boronic acid structure also tend to become unevenly distributed. In this embodiment, bonding between compounds having a boronic acid structure and the polyvinyl alcohol-based resin becomes more likely, and as a result, the adhesion between the cellulose acylate film and the resin layer containing the polyvinyl alcohol-based resin is further improved.

[0055] The surfactant preferably contains a repeating unit B having a hydrophilic group. The hydrophilic group is not particularly limited and includes hydroxyl groups, amide groups, substituted amide groups, carboxylic acid groups, sulfonic acid groups, phosphate groups, amide groups, tetrahydrofuryl groups, alkylpolyoxyalkylene groups, glycidyl groups, and isocyanate groups. In this specification, an amide group refers to a group represented by *-CONH2 (where * represents the bond position), and a substituted amide group refers to a group represented by *-CONR2 (where * represents the bond position, and R independently represents a hydrogen atom or an alkyl group (preferably an alkyl group having 1 to 5 carbon atoms)).

[0056] The surfactant preferably contains a repeating unit represented by formula (B) in that it provides superior effects of the present invention.

[0057]

[0058] In the above formula (B), R 1b and R 2b Each of these independently represents either a hydrogen atom or an alkyl group. 3b L represents a hydrogen atom or substituent. 1b represents a single bond or a divalent linking group. Examples of divalent linking groups include alkylene groups (preferably with 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms), -arylene groups, -CO-, -O-, -S-, -C(=S)-, and -NR 5b -, and combinations of two or more of these. R5b R represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms. Examples of combinations of two or more of these include -CO-O-alkylene group- and -CO-O-. 4b This represents a hydrophilic group. Examples of hydrophilic groups include the groups mentioned above.

[0059] Repeating unit B may be used alone or in combination of two or more types. The content of repeating unit B is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, relative to the total repeating units of the surfactant. Furthermore, the content of repeating unit B is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less, relative to the total repeating units of the surfactant.

[0060] The surfactant may contain repeating units other than repeating units A and B described above. The surfactant may contain repeating units comprising two or more ring structures selected from the group consisting of cycloalkane rings and monocyclic aromatic rings. A cycloalkane ring is a cyclic aliphatic saturated hydrocarbon ring, and examples include cyclohexane rings, cycloheptane rings, cyclooctane rings, cyclononane rings, cyclododecane rings, and cyclodocosane rings. Cyclohexane rings are preferred. On the other hand, a monocyclic aromatic ring is an unfused monocyclic aromatic ring or an individual monocyclic aromatic ring in a fused ring. That is, a phenyl group is a group having one benzene ring, which is a monocyclic aromatic ring, and a naphthyl group is a group having two benzene rings, which are monocyclic aromatic rings. Here, the number of atoms constituting the ring of a monocyclic aromatic ring is not particularly limited, but it is sufficient to be about 5 to 18, preferably 5 to 10, and more preferably 5 to 6. Furthermore, the monocyclic aromatic ring may be an aromatic ring consisting only of carbon atoms, or a heterocyclic aromatic ring that contains atoms other than carbon atoms in its ring structure. An example of an aromatic ring is a benzene ring. An example of a heterocyclic aromatic ring is an aromatic ring containing one or more atoms selected from sulfur atoms, nitrogen atoms, and oxygen atoms. A heterocyclic aromatic ring containing a sulfur atom is preferred, and one containing a sulfur atom is more preferred. Examples of heterocyclic aromatic rings include a thiophene ring, a pyrrole ring, an imidazole ring, a pyrazole ring, a furan ring, an isothiazole ring, an isoxazole ring, a pyridine ring, a pyridine ring, and a pyrimidine ring. A preferred monocyclic aromatic ring is a benzene ring, a thiophene ring, or a pyridine ring, with a benzene ring being more preferred.

[0061] The surfactant may contain a repeating unit C represented by formula (C).

[0062]

[0063] In the above formula (C), * represents the bond position. 1c and R 2c Each of these independently represents either a hydrogen atom or an alkyl group. 3c L represents a hydrogen atom or substituent. 1crepresents a single bond or a divalent linking group. Examples of divalent linking groups include alkylene groups (preferably with 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms), -arylene groups, -CO-, -O-, -S-, -C(=S)-, and -NR 5c -, and combinations of two or more of these. R 5c L represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms. 1c For example, the -O-alkylene group -O- can be cited. 2c and L 4c Each of these independently represents a cycloalkane ring or a monocyclic aromatic ring. 3c These are -O-, -CO-O-, -O-CH2-, or -CO-NR 5c This represents a negative value. q represents an integer greater than or equal to 1. q is preferably between 1 and 5, and more preferably between 1 and 3. R 4c The symbol represents a substituent. Examples of substituents include aliphatic hydrocarbon groups and acetylamino groups.

[0064] Repeating unit C may be used alone or in combination of two or more types. The content of repeating unit C is preferably 10% by mass or more, and more preferably 30% by mass or more, relative to the total repeating units of the surfactant. Furthermore, the content of repeating unit C is preferably 80% by mass or less, and more preferably 70% by mass or less, relative to the total repeating units of the surfactant.

[0065] From the standpoint of improving leveling properties, the weight-average molecular weight of the surfactant is preferably 2,000 to 40,000, and more preferably 10,000 to 35,000. Here, the weight-average molecular weight is the value measured by gel permeation chromatography (GPC) under the following conditions. • Solvent (eluent): Tetrahydrofuran • Instrument name: EcoSEC HLC-8320GPC (Tosoh Corporation) • Columns: Three columns connected together: TSKgel SuperHZM-H, TSKgel SuperHZ4000, and TSKgel SuperHZ200 (all Tosoh Corporation) • Column temperature: 40°C • Sample concentration: 0.1% by mass • Flow rate: 0.35 ml / min • Calibration curve: Calibration curve using six samples of TOSOH TSK standard polystyrene Mw = 706000 to 1013 (Mw / Mn = 1.03 to 1.06) was used.

[0066] The amount of surfactant in the composition is not particularly limited, but in terms of achieving superior effects of the present invention, it is preferably 0.01 to 1.0% by mass, and more preferably 0.05 to 0.5% by mass, relative to the total solid content of the composition.

[0067] The composition may contain other components besides compounds having a boronic acid structure and surfactants. Other components include (meth)acrylates, polymerization initiators, and solvents, which will be described later.

[0068] The (meth)acrylate composition may contain (meth)acrylate. Examples of (meth)acrylate include monofunctional (meth)acrylate and polyfunctional (meth)acrylate, and polyfunctional (meth)acrylate is preferred in that it provides superior effects of the present invention.

[0069] A monofunctional (meth)acrylate is a compound having one (meth)acryloyl group. A polyfunctional (meth)acrylate is a compound having two or more (meth)acryloyl groups. Examples of polyfunctional (meth)acrylates include polyfunctional acrylates and polyfunctional methacrylates. The number of (meth)acryloyl groups contained in a polyfunctional (meth)acrylate is not particularly limited, but is preferably 2 to 10, and more preferably 2 to 6. The acrylic equivalent of a polyfunctional acrylate is not particularly limited, but is preferably 150 g / eq. or less in terms of superior effects of the present invention and superior orientation of the liquid crystal layer. The lower limit is not particularly limited, but is often 80 g / eq. or more. Note that acrylic equivalent means the molecular weight per acryloyl group. In other words, acrylic equivalent is the molecular weight divided by the number of acryloyl groups. The methacrylic equivalent of the polyfunctional methacrylate is not particularly limited, but it is preferably 150 g / eq. or less in terms of superior effects of the present invention and superior orientation of the liquid crystal layer. The lower limit is not particularly limited, but it is often 80 g / eq. or more. The methacrylic equivalent refers to the molecular weight per methacryloyl group. In other words, the methacrylic equivalent is the molecular weight divided by the number of methacryloyl groups.

[0070] Examples of polyfunctional (meth)acrylates include 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, and dipentaerythritol hexaacrylate. Furthermore, examples of (meth)acrylates include various urethane acrylates such as urethane diacrylate and urethane hexaacrylate.

[0071] The content of (meth)acrylate in the composition is not particularly limited, but in terms of achieving superior effects of the present invention, it is preferably 30 to 95% by mass, more preferably 50 to 90% by mass, and even more preferably 60 to 85% by mass, based on the total solid content of the composition.

[0072] (Polymerization Initiators) The composition may contain polymerization initiators. Preferred polymerization initiators are photopolymerization initiators that can initiate the polymerization reaction by ultraviolet irradiation. Examples of photopolymerization initiators include α-carbonyl compounds, acyloin ethers, α-hydrocarbon-substituted aromatic acyloin compounds, polynuclear quinone compounds, and combinations of triarylimidazole dimers and p-aminophenyl ketones. Oxime-type polymerization initiators are also preferred. Specific examples include the initiators described in paragraphs

[0049] to

[0052] of International Publication No. 2017 / 170443.

[0073] The content of the polymerization initiator in the composition is not particularly limited, but in terms of achieving superior effects of the present invention, it is preferably 0.1 to 10% by mass, and more preferably 1.0 to 5.0% by mass, relative to the total solid content of the composition.

[0074] (Solvent) The composition may contain a solvent for ease of forming a specific layer. Preferred solvents are organic solvents, such as ketone solvents (e.g., acetone, 2-butanone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and cyclopentanone), ether solvents (e.g., dioxane and tetrahydrofuran), aliphatic hydrocarbon solvents (e.g., hexane), alicyclic hydrocarbon solvents (e.g., cyclohexane), aromatic hydrocarbon solvents (e.g., toluene, xylene, and trimethylbenzene), and halogenated carbon solvents (e.g., dichloromethane, dichloroethane, dichlorobenzene, and chlorotoluene). Examples of solvents include ester solvents (e.g., methyl acetate, ethyl acetate, and butyl acetate), alcohol solvents (e.g., ethanol, isopropanol, butanol, and cyclohexanol), cellosolve solvents (e.g., methyl cellosolve, ethyl cellosolve, and propylene glycol monomethyl ether), cellosolve acetate solvents (e.g., propylene glycol monomethyl ether acetate), sulfoxide solvents (e.g., dimethyl sulfoxide), and amide solvents (e.g., dimethylformamide and dimethylacetamide). Among these, ketone solvents or ester solvents are preferred as solvents. When the composition for forming a specific layer contains a ketone solvent or an ester solvent, the components in the composition become more easily absorbed into the cellulose acylate film when forming the specific layer, and the adhesion between the specific layer and the cellulose acylate film is further improved.

[0075] The solvent content in the composition is preferably 55 to 85% by mass, and more preferably 60 to 80% by mass, based on the total mass of the composition, in order to improve the coatability of the composition.

[0076] The specific layer is formed using the above composition. Among these, a preferred method for forming the specific layer is to apply the above composition onto a cellulose acylate film. Various known methods used for liquid coating, such as bar coating, gravure coating, and spray coating, can be used for applying the composition. Furthermore, if necessary, a drying treatment such as heat treatment may be applied to the coating film after application of the composition. Furthermore, if necessary, a curing treatment may be applied to the coating film after application of the composition to form the specific layer. The curing treatment method is not particularly limited, and examples include light irradiation treatment and heat treatment. Among these, light irradiation treatment is preferred from the viewpoint of manufacturability, and ultraviolet irradiation treatment is more preferred. The irradiation conditions for light irradiation treatment are not particularly limited, but 50 to 1000 mJ / cm² is preferred. ２ The irradiation dose is preferred. The atmosphere during the light irradiation treatment is not particularly limited, but a nitrogen atmosphere is preferred.

[0077] The thickness of the specific layer is not particularly limited, but is often 10 μm or less. A thickness of 3.0 μm or less is preferred because it provides excellent bending resistance for the optical film. The lower limit is not particularly limited, but is often 0.1 μm or more.

[0078] <Resin layer containing polyvinyl alcohol-based resin> The resin layer containing polyvinyl alcohol-based resin is a film placed on a specific layer. As will be described later, the liquid crystal layer is placed on this resin layer. This resin layer may also function as a so-called alignment film. For example, the resin layer may be a layer that has undergone a rubbing treatment, in which case it can function as an alignment film with alignment-regulating force.

[0079] Examples of polyvinyl alcohol-based resins included in the resin layer include polyvinyl alcohol (PVA) and modified polyvinyl alcohol (modified PVA). Modified PVA refers to a compound in which some of the hydroxyl groups of PVA are substituted with other functional groups (e.g., acetate groups) or to which other functional groups are bonded. Modified PVA preferably contains repeating units that include polymerizable groups. Examples of polymerizable groups include radical polymerizable groups, cationic polymerizable groups, and anionic polymerizable groups, with radical polymerizable groups being preferred. As a radical polymerizable group, (meth)acryloyl groups are preferred.

[0080] The content of polyvinyl alcohol-based resin in the resin layer is not particularly limited, but is preferably 80% by mass or more, and more preferably 90% by mass or more, relative to the total mass of the resin layer. There is no particular upper limit, but 100% by mass is an example.

[0081] The method for forming the resin layer is not particularly limited, and one method is to apply a composition containing a polyvinyl alcohol-based resin onto a specific layer to form the resin layer. Furthermore, if necessary, a drying treatment such as heat treatment may be applied to the coating film after application of the composition.

[0082] The thickness of the resin layer is not particularly limited, but is preferably 0.01 to 5.0 μm, and more preferably 0.1 to 1.0 μm.

[0083] <Liquid Crystal Layer> The liquid crystal layer is a layer placed on the resin layer described above. The liquid crystal layer is a layer formed using a liquid crystal compound, and may be a so-called optically anisotropic layer or a light-absorbing anisotropic layer. The optically anisotropic layer may be a so-called A plate or a C plate.

[0084] As the liquid crystal compound, either low-molecular-weight liquid crystal compounds or high-molecular-weight liquid crystal compounds can be used. Here, "low-molecular-weight liquid crystal compound" refers to a liquid crystal compound that does not have repeating units in its chemical structure. "High-molecular-weight liquid crystal compound" refers to a liquid crystal compound that has repeating units in its chemical structure. Examples of low-molecular-weight liquid crystal compounds include the liquid crystal compounds described in Japanese Patent Application Publication No. 2013-228706. Examples of high-molecular-weight liquid crystal compounds include the thermotropic liquid crystal polymers described in Japanese Patent Application Publication No. 2011-237513 and International Publication No. 2019 / 131943. Furthermore, high-molecular-weight liquid crystal compounds may have crosslinkable groups (e.g., acryloyl groups and methacryloyl groups) at their ends. Liquid crystal compounds may be used individually or in combination of two or more types.

[0085] As the liquid crystal compound, a liquid crystal compound having polymerizable groups (polymerizable liquid crystal compound) is preferred. Examples of polymerizable groups include unsaturated polymerizable groups, epoxy groups, and azilidinyl groups, with unsaturated polymerizable groups being preferred and ethylenically unsaturated polymerizable groups being more preferred. The liquid crystal compound may be a rod-shaped liquid crystal compound or a disc-shaped liquid crystal compound. In the liquid crystal layer, the liquid crystal compound may be fixed. To fix the liquid crystal compound, one method is to polymerize the polymerizable groups using the above-mentioned liquid crystal compound having polymerizable groups to fix the liquid crystal compound.

[0086] The liquid crystal layer may contain dichroic substances. The dichroic substances are not particularly limited as long as they exhibit dichroism, and include dichroic dyes, ultraviolet absorbers, infrared absorbers, nonlinear optical materials, carbon nanotubes, anisotropic metal nanoparticles, and inorganic materials. The liquid crystal layer may also contain two or more dichroic substances. Preferably, the liquid crystal layer contains, for example, a cyan dye that exhibits dichroism in the red wavelength range, a magenta dye that exhibits dichroism in the green wavelength range, and a yellow dye that exhibits dichroism in the blue wavelength range. Including multiple dichroic substances allows for a neutral color. Note that a dichroic substance is a substance that exhibits dichroism, and dichroism refers to the property of having different absorbances depending on the polarization direction.

[0087] As the dichroic substance, a dichroic dye is preferred, and a dichroic azo dye compound is more preferred. In the present invention, a dichroic azo dye compound means an azo dye compound in which the absorbance differs depending on the direction. The dichroic azo dye compound may or may not exhibit liquid crystalline properties. If the dichroic azo dye compound exhibits liquid crystalline properties, it may exhibit either a nematic liquid crystal phase or a smectic liquid crystal phase. The temperature range in which the liquid crystal 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 manufacturability.

[0088] Dichroic azo dye compounds may have crosslinking groups. Examples of crosslinking groups include (meth)acryloyl groups, epoxy groups, oxetanyl groups, and styryl groups, with (meth)acryloyl groups being preferred.

[0089] Examples of dichroic azo dye compounds include the first dichroic azo dye compound, the second dichroic azo dye compound, and the third dichroic azo dye compound. The first dichroic azo dye compound is a dichroic azo dye compound having a maximum absorption wavelength in the range of 560 nm to 700 nm. The second dichroic azo dye compound is a dichroic azo dye compound having a maximum absorption wavelength in the range of 455 nm to less than 560 nm. The third dichroic azo dye compound is a dichroic azo dye compound having a maximum absorption wavelength in the range of 380 nm to 455 nm. Specific examples of the first dichroic azo dye compound, the second dichroic azo dye compound, and the third dichroic azo dye compound include, for example, the compounds described in paragraphs

[0161] to

[0171] of International Publication No. 2022 / 138548, the compounds described in paragraphs

[0172] to

[0180] of International Publication No. 2022 / 138548, and the compounds described in paragraphs

[0183] to

[0206] of International Publication No. 2022 / 138548.

[0090] A light-absorbing anisotropic layer is preferred as the liquid crystal layer. A light-absorbing anisotropic layer formed using a composition containing a liquid crystal compound and a dichroic substance is preferred. The angle between the transmittance center axis of the light-absorbing anisotropic layer and the normal direction of the surface of the light-absorbing anisotropic layer is preferably 0 to 45°. The transmittance center axis of the light-absorbing anisotropic layer refers to the direction that exhibits the highest transmittance when the transmittance is measured while varying the tilt angle (polar angle) and tilt direction (azimuth angle) with respect to the normal direction of the surface (main surface) of the light-absorbing anisotropic layer. Specifically, the Müller matrix at a wavelength of 550 nm is measured using AxoScan (manufactured by Axometrics). More specifically, during measurement, the azimuthal angle at which the transmittance center axis is tilted is first identified. Then, within a plane containing the normal direction of the anisotropic light-absorbing layer along that azimuthal angle (a plane containing the transmittance center axis and perpendicular to the layer surface), the polar angle, which is the angle with respect to the normal direction of the anisotropic light-absorbing layer surface, is changed in 1° increments from -70° to 70°, and the Müller matrix at a wavelength of 550 nm is measured to derive the transmittance of the anisotropic light-absorbing layer. The direction with the highest transmittance as a result is defined as the transmittance center axis. Note that if the anisotropic light-absorbing layer contains dichroic material, the transmittance center axis represents the direction of the absorption axis (the long axis direction of the molecule) of the dichroic material contained in each anisotropic light-absorbing layer.

[0091] The method for forming the liquid crystal layer is not particularly limited. For example, a liquid crystal layer-forming composition containing a polymerizable liquid crystal compound may be applied, the formed coating film may be subjected to an orientation treatment to orient the polymerizable liquid crystal compound in the coating film, and then a curing treatment may be performed to form a liquid crystal layer. The content of the polymerizable liquid crystal compound in the liquid crystal layer-forming composition is preferably 60 to 99% by mass, and more preferably 70 to 98% by mass, based on the total solid content of the liquid crystal layer-forming composition. The liquid crystal layer-forming composition may also contain the dichroic substance described above. When the liquid crystal layer-forming composition contains a dichroic substance, the resulting liquid crystal layer may be a light-absorbing anisotropic layer. The content of the dichroic substance is preferably 1 to 30% by mass, and more preferably 5 to 25% by mass, based on the total solid content of the liquid crystal layer-forming composition. The liquid crystal layer-forming composition may also contain other components besides the polymerizable liquid crystal compound and the dichroic substance. Other components include polymerization initiators, orientation agents, compounds having the boronic acid structure described above, and solvents.

[0092] Various known methods used for coating liquids, such as bar coating, gravure coating, and spray coating, can be used as methods for coating compositions for forming liquid crystal layers.

[0093] Orientation treatment can be performed by drying the coating film at room temperature or by heating the coating film. In the case of thermotropic liquid crystal compounds, the liquid crystal phase formed by the orientation treatment can generally be transferred by changes in temperature or pressure. In the case of lyotropic liquid crystal compounds, the transfer can also be performed by changing the composition ratio, such as the amount of solvent. There are no particular restrictions on the conditions for heating the coating film, but the heating temperature is preferably 50 to 250°C, more preferably 50 to 150°C, and the heating time is preferably 10 seconds to 10 minutes. Furthermore, after heating the coating film, it may be cooled as needed before the curing treatment (light irradiation treatment) described later.

[0094] The curing method applied to a coating film on which polymerizable liquid crystal compounds are oriented is not particularly limited and includes, for example, light irradiation and heat treatment. Among these, light irradiation is preferred from the viewpoint of manufacturability, and ultraviolet irradiation is more preferred. The irradiation conditions for light irradiation are not particularly limited, but 50 to 1000 mJ / cm² is preferred. 2 The irradiation dose is preferred. The atmosphere during the light irradiation treatment is not particularly limited, but a nitrogen atmosphere is preferred.

[0095] The thickness of the liquid crystal layer is not particularly limited, but is preferably 0.1 to 10 μm, and more preferably 1 to 5 μm.

[0096] <Other Layers> The optical film may include the cellulose acylate film, specific layer, resin layer containing a polyvinyl alcohol-based resin, and other layers other than the liquid crystal layer. The optical film may also include a protective layer on the liquid crystal layer (on the side of the liquid crystal layer opposite to the resin layer). The protective layer preferably contains a resin. The resin is not particularly limited, but the polyvinyl alcohol-based resin described above is preferred.

[0097] The protective layer is preferably formed from a composition containing a compound selected from the group consisting of polyfunctional acrylates and polyfunctional methacrylates (polyfunctional (meth)acrylate), as it provides superior heat resistance to the liquid crystal layer.

[0098] The number of (meth)acryloyl groups contained in the polyfunctional (meth)acrylate is not particularly limited, but is preferably 2 to 10, and more preferably 2 to 6. The acrylic equivalent of the polyfunctional acrylate is not particularly limited, but is preferably 150 g / eq. or less in terms of superior adhesion between the liquid crystal layer and the protective layer. The lower limit is not particularly limited, but is preferably 80 g / eq. or more. Note that acrylic equivalent means the molecular weight per acryloyl group. In other words, acrylic equivalent is the molecular weight divided by the number of acryloyl groups. The methacrylic equivalent of the polyfunctional methacrylate is not particularly limited, but is preferably 150 g / eq. or less in terms of superior adhesion between the liquid crystal layer and the protective layer. The lower limit is not particularly limited, but is preferably 80 g / eq. or more. Note that methacrylic equivalent means the molecular weight per methacryloyl group. In other words, methacrylic equivalent is the molecular weight divided by the number of methacryloyl groups.

[0099] Examples of polyfunctional (meth)acrylates include 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, and dipentaerythritol hexaacrylate. Furthermore, examples of polyfunctional (meth)acrylates include urethane diacrylate and various urethane acrylates such as urethane hexaacrylate.

[0100] From the standpoint of superior adhesion between the liquid crystal layer and the protective layer, and better heat resistance of the liquid crystal layer, the molecular weight of the polyfunctional (meth)acrylate is preferably 2000 or less, more preferably 1500 or less, and even more preferably 1000 or less. By using a low molecular weight polyfunctional (meth)acrylate in the protective layer forming composition, the polyfunctional (meth)acrylate penetrates into the liquid crystal layer during protective layer coating, and subsequent curing can further increase the crosslinking density within the liquid crystal layer. In the case of a light-absorbing anisotropic layer containing a dichroic substance, the improvement in crosslinking density suppresses thermal fluctuations of the dichroic substance, thereby improving heat resistance. There is no particular lower limit to the molecular weight of the above-mentioned polyfunctional (meth)acrylate, but it is often 300 or more, and more often 500 or more.

[0101] To further suppress the repulsion of the protective layer, the viscosity of the polyfunctional (meth)acrylate at 25°C is preferably 10,000 mPa·s or higher, more preferably 15,000 mPa·s or higher, and even more preferably 20,000 mPa·s or higher. By using a highly viscous polyfunctional (meth)acrylate in the protective layer forming composition, the occurrence of repulsion during coating and drying of the protective layer can be suppressed. There is no particular upper limit to the viscosity, but it is often 50,000 mPa·s or lower. The viscosity of the polyfunctional (meth)acrylate can be measured by the following method. If the polyfunctional (meth)acrylate is a commercially available product and the viscosity at 25°C is listed in the catalog, that value should be used. The viscosity of the polyfunctional (meth)acrylate is measured in the range of 25 ± 0.2°C using a RE-80L rotational viscometer manufactured by Toki Sangyo Co., Ltd.

[0102] The content of (meth)acrylate in the composition is not particularly limited, but in terms of superior effects of the present invention, it is preferably 30 to 99% by mass, more preferably 50 to 95% by mass, and even more preferably 60 to 90% by mass, based on the total solid content of the composition.

[0103] From the standpoint of improving adhesion, heat resistance, and water repellency as described above, it is preferable that the liquid crystal layer be directly laminated with the protective layer.

[0104] The thickness of the protective layer is not particularly limited, and is often 10 μm or less. However, 3.0 μm or less is preferred because it provides excellent bending resistance for the optical film. The lower limit is not particularly limited, and is often 0.1 μm or more.

[0105] [Liquid Crystal Cell] The optical film of the present invention can be applied to a viewing angle control system. When the optical film of the present invention has a light-absorbing anisotropic layer as a liquid crystal layer, the liquid crystal cell included in the viewing angle control system is placed between the light-absorbing anisotropic layer in the optical film of the present invention and a polarizer, and switches between a light-shielding mode and a transmission mode by controlling the orientation direction of the liquid crystal compound contained in the liquid crystal cell. The liquid crystal cell is not particularly limited as long as it can switch between a light-shielding mode and a transmission mode, and known liquid crystal cells can be used. The liquid crystal cell may have a plurality of regions in which the orientation direction of the liquid crystal compound can be controlled. When the liquid crystal cell has a plurality of regions in which the orientation direction of the liquid crystal compound can be controlled, it is also possible to independently control the orientation direction of the liquid crystal compound in each region and switch between a light-shielding mode and a transmission mode for the region of the display panel corresponding to each region.

[0106] The liquid crystal cell method is not particularly limited, and known methods can be used. Examples of liquid crystal cell methods include in-plane switching (IPS), twisted nematic (TN), vertical alignment (VA), ECB (Electrically Controlled Birefringence), and OCB (Optically Compensated Bend). Furthermore, the liquid crystal cell may be of the STN (Super Twisted Nematic) type having a twist angle of 180° or more, or of the VATN (Vertically Aligned Twisted Nematic) type disclosed in Japanese Patent Application Publication No. 10-123576, in which rod-shaped liquid crystal molecules are substantially vertically oriented when no voltage is applied, and the liquid crystal layer is twisted to 60 to 120° when a voltage is applied.

[0107] In particular, the liquid crystal cell method is preferably selected from the group consisting of the TN method, IPS method, ECB method, and VA method, with the IPS method being preferred. In the TN method liquid crystal cell, when no voltage is applied, the rod-shaped liquid crystal molecules are substantially oriented horizontally and further twisted to 60 to 120 degrees along the thickness direction. The TN method liquid crystal cell is the most widely used as a color TFT (Thin Film Transistor) liquid crystal display device and is described in numerous publications.

[0108] In VA-type liquid crystal cells, rod-shaped liquid crystalline molecules are substantially oriented vertically when no voltage is applied. VA-type liquid crystal cells include (1) VA-type liquid crystal cells in the narrow sense (described in Japanese Patent Publication No. 2-176625) in which rod-shaped liquid crystalline molecules are substantially oriented vertically when no voltage is applied and substantially horizontally when voltage is applied; (2) multi-domain liquid crystal cells (MVA type) (described in SID97, Digest of tech. Papers (Proceedings) 28 (1997) 845), (3) liquid crystal cells of the type (n-ASM type) in which rod-shaped liquid crystalline molecules are substantially oriented vertically when no voltage is applied and twisted multi-domain orientation when voltage is applied (described in the Proceedings of the Japan Liquid Crystal Symposium 58-59 (1998)); and (4) SURVIVAL type liquid crystal cells (presented at LCD International 98). Furthermore, any of the following methods may be used: PVA (Patterned Vertical Alignment), Optical Alignment, or PSA (Polymer-Sustained Alignment). For further details, please refer to Japanese Patent Publication No. 2006-215326 and Japanese Patent Publication No. 2008-538819.

[0109] In IPS liquid crystal cells, rod-shaped liquid crystal molecules are oriented substantially parallel to the substrate, and by applying a voltage between electrodes to create an electric field parallel to the substrate surface, the liquid crystal molecules respond in a planar manner.

[0110] In ECB (Electronic Cross-Blocking) liquid crystal cells, an electric field is generated perpendicular to the substrate surface, and this field changes the alignment direction of the liquid crystal compounds. Generally, in ECB liquid crystal cells, when an electric field is generated, the liquid crystal compounds align along the thickness direction of the cell.

[0111] When the liquid crystal cell is of the IPS type, the in-plane retardation (Re(550)) of the liquid crystal cell is preferably 100 to 500 nm, and more preferably 120 to 450 nm. Furthermore, when the liquid crystal cell is of the IPS type, the orientation direction of the liquid crystal compound can be controlled in the in-plane direction, but it is preferable that the angle between the absorption axis of the polarizer and the in-plane slow axis of the liquid crystal cell can be controlled to at least 0 to 5° or 85 to 95°. By controlling the orientation direction of the liquid crystal compound within the above range, it is possible to emit light from the liquid crystal cell without changing the polarization state of the light emitted from the polarizer. When the liquid crystal cell is of the IPS type and the liquid crystal cell changes the polarization direction of the light emitted from the polarizer, the angle between the absorption axis of the polarizer and the in-plane slow axis of the liquid crystal cell can be appropriately adjusted according to the value of the in-plane retardation of the liquid crystal cell. When changing the polarization direction as described above, it is preferable that the angle between the absorption axis of the polarizer and the in-plane slow axis of the liquid crystal cell be controllable to 15 to 75°, and more preferably to 20 to 70°. The above angle is more preferably 20 to 40° or 50 to 70°, and particularly preferably 20 to 30° or 60 to 70°, in terms of being superior in at least one of light shielding and transmittance.

[0112] If the liquid crystal cell is of the IPS type, it is preferable that it satisfies either requirement 1 or requirement 2 below. Requirement 1: The in-plane retardation (Re(550)) of the IPS type liquid crystal cell at a wavelength of 550 nm is 300 to 450 nm. Requirement 2: The IPS type liquid crystal cell is switchable between two states, in one of the two states the angle between the in-plane slow axis of the liquid crystal cell and the absorption axis of the polarizer is 0 to 5° or 85 to 95°, and in the other of the two states the angle between the in-plane slow axis of the liquid crystal cell and the absorption axis of the polarizer is 20 to 35°.

[0113] If the liquid crystal cell is of the VA or ECB type, it is preferable that requirements 3 and 4 below are met. It is even more preferable that requirements 3, 4 and 5 below are met. Requirement 3: The Δnd of the VA or ECB type liquid crystal cell at a wavelength of 550 nm is 500 to 900 nm. Requirement 4: The VA or ECB type liquid crystal cell is switchable between two states, and in one of the two states, the angle between the in-plane slow axis of the liquid crystal cell and the absorption axis of the polarizer is 0 to 10°. Requirement 5: In one of the two states in requirement 4 above, the voltage of the liquid crystal cell is 1.5 to 3.5 V, and in the other of the two states, the voltage is OFF.

[0114] Furthermore, the liquid crystal cell may be capable of being controlled to an intermediate state between the light-shielding mode and the transmission mode (halftone display). That is, in a liquid crystal cell, the orientation direction of the liquid crystal compound may be controlled to an intermediate state between the orientation direction of the liquid crystal compound in the light-shielding mode and the orientation direction of the liquid crystal compound in the transmission mode. When halftone display is performed, the liquid crystal compound is oriented in a predetermined direction, so the magnitude of birefringence produced by the liquid crystal compound when observed from an oblique angle differs between the orientation direction and the direction perpendicular to the orientation direction, which can result in differences in brightness and color tone. Here, the region in which the orientation direction of the liquid crystal compound of the liquid crystal cell can be controlled (for example, the region corresponding to a single pixel of the display panel) may be further divided into multiple regions, creating a structure called a multi-domain. With a multi-domain structure, the viewing angle characteristics of brightness and color tone are averaged out, making it easier to reduce differences in brightness and color tone. Specifically, by averaging each of the above regions of the liquid crystal cell (for example, the region corresponding to a single pixel) with two or more regions in which the initial orientation states of the liquid crystal molecules are different from each other, the bias in brightness and color tone that depends on the viewing angle can be reduced. Furthermore, similar effects can be obtained by configuring each of the above regions from two or more different regions in which the orientation direction of the liquid crystal compound changes continuously when a voltage is applied.

[0115] In any of the above-described liquid crystal cell modes, the above-mentioned region of the liquid crystal cell (for example, the region corresponding to a single pixel) may be divided into multiple regions, a structure known as the multi-domain structure. A multi-domain structure is preferable because it averages the viewing angle characteristics in the vertical and horizontal directions, improving display quality.

[0116] The viewing angle control system of the present invention may have an optical compensation layer between the light absorption anisotropy layer and the liquid crystal cell, and between the liquid crystal cell and the polarizer, at least one of these. The optical compensation layer preferably exhibits a phase difference (Rth) in the thickness direction. The absolute value of Rth of the optical compensation layer is preferably 50 nm or more, and more preferably 100 nm or more. The absolute value of Rth of the optical compensation layer is preferably 600 nm or less, and more preferably 500 nm or less. Furthermore, the in-plane phase difference (Re) of the optical compensation layer is preferably 0 nm or more, and more preferably 3 nm or more. Furthermore, Re of the optical compensation layer is preferably 300 nm or less, and more preferably 250 nm or less. In addition, the Nz factor of the optical compensation layer is preferably -100 to 100, and more preferably -75 to 75. Here, the Nz factor means the value expressed as Nz = (nx - nz) / (nx - ny). As the optical compensation layer, an A plate, a B plate, or a C plate is preferred, a B plate or a C plate is more preferred, and a B plate is even more preferred.

[0117] <Applications> The optical film of the present invention can be applied to various applications, for example, to display devices. Examples of display devices include liquid crystal displays, organic electroluminescent displays, micro-LED displays, head-up displays, and head-mounted displays.

[0118] The features of the present invention will be described in more detail below with reference to examples and comparative 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 specific examples shown below.

[0119] <Example 1> (Preparation of base material) The following components were 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, and the solvent of the dope was methylene chloride / methanol / butanol = 81 / 18 / 1 (by mass ratio).

[0120] -------------------------------------------------- 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

[0121]

[0122]

[0123] 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).

[0124] 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 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.

[0125] (Formation of specific layer UL1) The specific layer-forming composition UL1, described later, was continuously applied to the cellulose acylate film A1 using a wire bar. The cellulose acylate film with the coating was dried with 60°C hot air for 60 seconds, and then heated with 300 mJ / cm using an LED (light emitting diode) lamp (center wavelength 365 nm). 2 A specific layer UL1 was fabricated on the cellulose acylate film A1 by irradiation under the following irradiation conditions. The thickness of the specific layer UL1 was 0.4 μm. -------------------------------------------------- Composition of the specific layer-forming composition UL1 -------------------------------------------------- NK ester A-TMMT (manufactured by Shin Nakamura Chemical Co., Ltd.) 9.23 parts by mass Boronic acid compound B-1 (see below) 2.40 parts by mass IRGACUREOXE-02 (manufactured by BASF) 0.35 parts by mass Surfactant S-1 (see below) 0.024 parts by mass Butyl acetate 74.80 parts by mass Methyl ethyl ketone 13.20 parts by mass --------------------------------------------------

[0126] Boronic acid compound B-1

[0127]

[0128] Surfactant S-1 (The numerical value indicated for each repeating unit represents the content (mass%) of each repeating unit relative to the total number of repeating units. n is 9. The weight-average molecular weight is 11000. Ac represents an acetyl group.)

[0129]

[0130] (Formation of a resin layer containing PVA) The resin layer-forming composition 1 containing PVA described below was applied to the obtained cellulose acylate film with the specific layer using a wire bar. After the coating was formed, it was dried with hot air at 60°C for 60 seconds, and then with hot air at 100°C for 120 seconds to form a resin layer AL1 containing PVA. The thickness of the resin layer AL1 containing PVA was 0.15 μm.

[0131] ------------------------------------------------------------------- Composition 1 for forming a resin layer ------------------------------------------------------------------- Modified polyvinyl alcohol PVA-1 1.81 parts by mass Water 75.39 parts by mass Methanol 22.80 parts by mass -------------------------------------------------------------------

[0132] (Modified polyvinyl alcohol PVA-1) Note that the composition ratio of each repeating unit is based on mol%.

[0133]

[0134] (Formation of the light-absorbing anisotropic layer (corresponding to the liquid crystal layer)) The following light-absorbing anisotropic layer forming composition P1 was continuously applied to the obtained PVA-containing resin layer AL1 using a wire bar, and the coating was heated at 120°C for 60 seconds, then cooled to room temperature (23°C). Next, the coating was heated at 75°C for 60 seconds and cooled again to room temperature. After that, an LED lamp (center wavelength 365 nm) was used to illuminate the coating from the normal direction at an illuminance of 200 mW / cm². 2 A light-absorbing anisotropic layer V1 was fabricated on a resin layer AL1 containing PVA by irradiating it for 2 seconds under the specified irradiation conditions. The thickness of the light-absorbing anisotropic layer V1 was 3.5 μm.

[0135] ------------------------------------------------------------ Composition P1 for forming anisotropic light-absorbing layer ------------------------------------------------------------ • The following dichroic substance D-1 0.76 parts by mass • The following dichroic substance D-2 0.04 parts by mass • The following dichroic substance D-3 1.13 parts by mass • The following polymer liquid crystal compound P-1 3.93 parts by mass • The following liquid crystal compound L-1 2.43 parts by mass • IRGACURE OXE-2 (manufactured by BASF) 0.13 parts by mass • The following orientation agent E-1 0.05 parts by mass • The following boronic acid compound B-2 0.28 parts by mass • The following surfactant S-2 0.008 parts by mass • Cyclopentanone 82.11 parts by mass • Benzyl alcohol 9.12 parts by mass ------------------------------------------------------------

[0136] Dichroic substance D-1

[0137]

[0138] Dichroic substance D-2

[0139]

[0140] Dichroic substance D-3

[0141]

[0142] Polymeric liquid crystal compound P-1 (The numerical values ​​indicated for each repeating unit ("59", "15", "26") represent the content (mass %) of each repeating unit relative to the total number of repeating units. The weight-average molecular weight is 21,000.)

[0143]

[0144] Liquid crystal compound L-1 [A mixture of the following liquid crystal compounds (RA), (RB), and (RC) in a mass ratio of 84:14:2]

[0145]

[0146] Orienting agent E-1

[0147]

[0148] Boronic acid compound B-2

[0149]

[0150] Surfactant S-2 (The numerical values ​​indicated for each repeating unit ("40", "40", "20") represent the content (mass %) of each repeating unit relative to the total number of repeating units. The weight-average molecular weight is 11,000.)

[0151]

[0152] (Formation of protective layer B1) The protective layer-forming composition B1 described below was continuously applied to the obtained light-absorbing anisotropic layer V1 using a wire bar to form a coating film. The coating film was then dried with 60°C hot air for 60 seconds, and then with 100°C hot air for 120 seconds to form protective layer B1, and an optical film 1 was produced. The thickness of the protective layer was 0.5 μm. --------------------------------------------------------------------------- Composition B1 for forming a protective layer --------------------------------------------------------------------------- Modified polyvinyl alcohol PVA-1 3.19 parts by mass IRGACURE 2959 (manufactured by BASF) 0.17 parts by mass BYK 348 (manufactured by BYK) 0.02 parts by mass The following mixed solution 1 2.26 parts by mass Water 70 parts by mass Methanol 30 parts by mass --------------------------------------------------------------------------- Composition B1 for forming a protective layer --------------------------------------------------------------------------- Modified polyvinyl alcohol PVA-1 3.19 parts by mass IRGACURE 2959 (manufactured by BASF) 0.17 parts by mass BYK 348 (manufactured by BYK) 0.02 parts by mass Mixed solution 1 2.26 parts by mass Water 70 parts by mass Methanol 30 parts by mass ---------------------------------------------------------------------------

[0153] -------------------------------------------------- Mixture 1 -------------------------------------------------- ・2,5-dimethoxytetrahydrofuran 0.80 parts by mass ・Pyridinium p-toluenesulfonate 0.24 parts by mass ・Water 8.96 parts by mass -------------------------------------------------- Mixture 1 was heated and stirred at 40°C for 4 hours, and then mixed with the other components to prepare protective layer forming composition B1.

[0154] <Examples 2-19, Comparative Examples 1-3> Optical films of Examples 2-19 and Comparative Examples 1-3 were prepared in the same manner as in Example 1, by changing the amount of compounds having a boronic acid structure and other compounds so that they matched the "mass ratios" shown in Tables 1-3 below for each optical film 1 prepared in Example 1. In Comparative Example 3, no specific layer was provided. As will be described later, the "mass ratio" in Table 1 represents the content (mass%) of compounds having a boronic acid structure relative to the total solid content of the specific layer-forming composition.

[0155] <Example 20> On the light-absorbing anisotropic layer V1 prepared in Example 1, the protective layer-forming composition B2 described below was continuously applied with a wire bar to form a coating film. Next, the coating film was dried with 80°C hot air for 60 seconds to form the protective layer B2, and then cooled to room temperature (23°C). After that, an LED lamp (center wavelength 365 nm) was used to illuminate the coating film from the normal direction with an illuminance of 200 mW / cm². 2By irradiating under the following conditions for 2 seconds, a protective layer B2 was formed on the light-absorbing anisotropic layer V1, and an optical film 20 was fabricated. The thickness of the protective layer B2 was 1.0 μm. ------------------------------------------------------------------- Composition B2 for forming the protective layer ------------------------------------------------------------------- ・UA-306I (manufactured by Kyoeisha Chemical Co., Ltd.) 19.42 parts by mass ・IRGACURE OXE-2 (manufactured by BASF) 0.56 parts by mass ・The above surfactant S-2 0.02 parts by mass ・Isopropyl alcohol 67.38 parts by mass ・Propylene glycol monomethyl ether 12.62 parts by mass -------------------------------------------------------------------

[0156] <Example 21> An optical film of Example 21 was prepared by following the same procedure as in Example 20, except that the light absorption anisotropy layer forming composition P1 was replaced with the light absorption anisotropy layer forming composition P2 described below.

[0157] ------------------------------------------------------------ Composition P2 for forming anisotropic light-absorbing layer ------------------------------------------------------------ • Dichroic substance D-1 0.76 parts by mass • Dichroic substance D-2 0.04 parts by mass • Dichroic substance D-3 1.13 parts by mass • Polymer liquid crystal compound P-1 4.11 parts by mass • Liquid crystal compound L-1 2.54 parts by mass • IRGACURE OXE-2 (manufactured by BASF) 0.13 parts by mass • Orienting agent E-1 0.05 parts by mass • Surfactant S-2 0.008 parts by mass • Cyclopentanone 82.11 parts by mass • Benzyl alcohol 9.12 parts by mass ------------------------------------------------------------

[0158] <Examples 22-26> Optical films of Examples 22-26 were prepared in the same procedure as in Example 21, except that the materials used to form the specific layer and protective layer were changed as shown in Table 4 below.

[0159] <Example 27> (Preparation of optical compensation layer) (Extrusion molding) Cycloolefin resin ARTON G7810 (manufactured by JSR Corporation) was dried at 100°C for more than 2 hours and melt-extruded at 280°C using a twin-screw compounding extruder. At this time, a screen filter, a gear pump, and a leaf disc filter were placed in this order between the extruder and the die, and these were connected by melt piping. The film was extruded from a T-die with a width of 1000 mm and a lip gap of 1 mm, and cast onto three consecutive cast rolls set to 180°C, 175°C, and 170°C to obtain an unstretched film 1 with a width of 900 mm and a thickness of 94 μm.

[0160] (Stretching and heat fixing) The unstretched film 1 being transported was subjected to a stretching process and a heat fixing process in the following manner.

[0161] (a) Longitudinal stretching An unstretched film 1 was longitudinally stretched under the following conditions while being transported using a roll-to-roll longitudinal stretching machine with an aspect ratio (L / W) of 0.2. -Conditions- Preheating temperature: 170°C Stretching temperature: 170°C Stretching ratio: 230% (b) Transverse stretching The longitudinally stretched film was transversely stretched under the following conditions while being transported using a tenter. -Conditions- Preheating temperature: 170°C Stretching temperature: 170°C Stretching ratio: 10%

[0162] (c) Following the heat-fixing stretching process, the stretched film was held at both ends with tenter clips to maintain a constant width (within a range of expansion or contraction of 3%), and then heat-treated under the following conditions to perform heat-fixing: Heat-fixing temperature: 165°C Heat-fixing time: 30 seconds Note that the preheating temperature, stretching temperature, and heat-fixing temperature are the average values ​​of measurements taken at five points in the width direction using an infrared thermometer.

[0163] (Winding) After heat fixing, both ends were trimmed and the film was wound under a tension of 25 kg / m to obtain a film roll of stretched film with a width of 1340 mm and a length of 2000 m. The obtained stretched film had a Re of 120 nm, a Rth of 420 nm, and an Nz factor of 4.0. The stretched film obtained by the above procedure was used as optical compensation layer 1.

[0164] [Fabrication of polarizing plates] Using the same method as the polarizing plate 02 with a protective film on one side described in International Publication No. 2015 / 166991, a polarizing plate with a polarizer thickness of 8 μm and one side of the polarizer exposed was fabricated.

[0165] [Fabrication of IPS Liquid Crystal Cell] An IPS liquid crystal cell having a liquid crystal layer between two glass substrates was fabricated. When forming the liquid crystal cell, an orientation layer was formed on the glass substrate by performing a photo-alignment treatment based on Example 11 of Japanese Patent Application Publication No. 2005-351924, and a liquid crystal layer in which the liquid crystal compound was oriented was formed within the liquid crystal cell. The tilt angle of the liquid crystal compound with respect to the substrate surface was 0.1°. The Δn of the liquid crystal compound in the liquid crystal layer was 0.08625 at a wavelength of 550 nm, and Δnd was adjusted by adjusting the gap (d) between the substrates. The in-plane retardation of liquid crystal cell 1 was 275 nm (λ / 2). An IPS liquid crystal cell, which is an IPS type liquid crystal cell, was obtained by the above procedure.

[0166] [Fabrication of Viewing Angle Control System 1] The fabricated optical compensation layer 1 was bonded to one side of the fabricated IPS liquid crystal cell using a commercially available adhesive (SK2057, manufactured by Soken Chemical Co., Ltd.). Next, the optical film of Example 25 was bonded to the side of the bonded optical compensation layer 1 opposite to the IPS liquid crystal cell side using a commercially available adhesive SK2057 (manufactured by Soken Chemical Co., Ltd.). Then, the fabricated polarizing plate was bonded to the side of the IPS liquid crystal cell opposite to the side to which the optical compensation layer 1 was bonded using a commercially available adhesive (SK2057, manufactured by Soken Chemical Co., Ltd.) to fabricate the viewing angle control system 1. At this time, the polarizing plate was bonded so that its absorption axis and the slow phase axis of the optical compensation layer 1 were parallel. Furthermore, during the above bonding process, the IPS liquid crystal cell was positioned such that the angle between the in-plane slow axis of the liquid crystal layer and the absorption axis of the polarizer was 45° when voltage was applied, and the angle between the in-plane slow axis of the liquid crystal layer and the absorption axis of the polarizer was 0° when no voltage was applied.

[0167] [Fabrication of Image Display Device A1] A Cosmo Shine Super Birefringent Type (SRF, registered trademark, manufactured by Toshiba Corporation), a depolarizing film, was bonded to the display screen of a dynabook (registered trademark, manufactured by Toshiba Corporation), a notebook computer equipped with a liquid crystal display, using a commercially available adhesive SK2057 (manufactured by Soken Chemical Co., Ltd.). Next, the above-fabricated viewing angle control system 1 was placed on the depolarizing film to fabricate an image display device A1 with a viewing angle control function. With the fabricated image display device A1, the angle between the in-plane slow axis of the liquid crystal layer in the IPS liquid crystal cell and the absorption axis of the polarizer could be switched between 45° and 0° by turning the voltage applied to the IPS liquid crystal cell ON and OFF. When the vertical direction of the image display area of ​​the above-mentioned laptop is defined as 0° of azimuth, it was confirmed that the light-shielding mode and the light-transmitting mode can be switched by turning the voltage applied to the IPS liquid crystal cell ON and OFF when viewing the image display device A1 from an oblique direction at azimuth angles of 90° and 270°.

[0168] <Example 28> An image display device A2 was manufactured following the same procedure as in Example 27, except that a second optical film from Example 25 was laminated to the side of the optical film from Example 25 opposite to the optical compensation layer 1 using adhesive SK2057 (manufactured by Soken Chemical Co., Ltd.).

[0169] <Example 29> An image display device A3 was manufactured following the same procedure as in Example 27, except that a second optical film from Example 25 was laminated to the side of the optical film from Example 25 opposite to the optical compensation layer 1 using adhesive SK2057 (manufactured by Soken Chemical Co., Ltd.), and a third optical film from Example 25 was laminated using adhesive SK2057 (manufactured by Soken Chemical Co., Ltd.).

[0170] <Example 30> An optical film of Example 30 was prepared by following the same procedure as in Example 25, except that a resin layer containing PVA, which is the second layer, and a light-absorbing anisotropic layer were formed again in this order on top of the light-absorbing anisotropic layer, and a protective layer was formed on top of the second light-absorbing anisotropic layer. An image display device A4 was prepared by following the same procedure as in Example 27, except that the optical film of Example 25 was changed to the optical film of Example 30.

[0171] <Example 31> An optical film of Example 31 was prepared by following the same procedure as in Example 30, except that a resin layer containing PVA, which is the third layer, and a light-absorbing anisotropic layer were formed again in this order on the second light-absorbing anisotropic layer, and a protective layer was formed on the third light-absorbing anisotropic layer. An image display device A5 was prepared by following the same procedure as in Example 27, except that the optical film of Example 25 was replaced with the optical film of Example 31.

[0172] <Example 32> An optical film of Example 32 was prepared according to the same procedure as in Example 30, except that the thickness of both of the two light-absorbing anisotropic layers was formed to 5.3 μm. An image display device A6 was prepared according to the same procedure as in Example 27, except that the optical film of Example 25 was replaced with the optical film of Example 32.

[0173] <Example 33> [Fabrication of VA liquid crystal cell] An electrode-equipped glass substrate was immersed for 30 seconds in a solution of household neutral detergent diluted with 50 cc of water, and then air-dried. Separately, an alignment film for liquid crystal material ("JALS-2021-R1", manufactured by JSR Corporation) was formed on a glass substrate that had been washed separately, and the formed alignment film for liquid crystal material was subjected to a rubbing treatment. The electrode-equipped glass substrate and the glass substrate on which the alignment film was formed were assembled into a liquid crystal cell with the rubbing treatment side facing inward. The liquid crystal cell was fabricated by drop-injecting a liquid crystal material with negative dielectric anisotropy ("MLC6608", manufactured by Merck) between the substrates to seal it, and forming a liquid crystal layer between the substrates so that it was vertically aligned. At this time, the cell gap between the substrates was adjusted so that Δnd at a wavelength of 550 nm was 275 nm. A VA liquid crystal cell, which is a VA type liquid crystal cell, was obtained using the above procedure. In the VA liquid crystal cell, the orientation direction of the liquid crystal material (liquid crystal compound) changes from vertical to horizontal orientation when a voltage is applied.

[0174] [Fabrication of Viewing Angle Control System 7] An optical compensation layer 1 was bonded to one side of the fabricated VA liquid crystal cell using a commercially available adhesive (SK2057, manufactured by Soken Chemical Co., Ltd.). Next, a polarizing plate was bonded using a commercially available adhesive SK2057 (manufactured by Soken Chemical Co., Ltd.) so that the polarizer surface and the side of the optical compensation layer 1 opposite to the VA liquid crystal cell side faced each other. At this time, the orientation relationship during bonding was adjusted so that the absorption axis of the polarizing plate and the slow phase axis of the optical compensation layer 1 were parallel. Next, three optical films from Example 25 were bonded to the side of the VA liquid crystal cell opposite to the side to which the polarizing plate was bonded, in the same manner as in Example 29, to obtain a viewing angle control system A7. At this time, the bonding was performed so that the angle between the orientation direction of the liquid crystal in the state applied to the VA liquid crystal cell and the absorption axis of the polarizing plate was 45°.

[0175] [Fabrication of Image Display Device A7] Image display device A7 was fabricated following the same procedure as in Example 27, except that the viewing angle control system 1 in Example 27 was changed to a viewing angle control system 7. It was confirmed that the fabricated image display device A7 could be switched between a light-shielding mode (ON) and a transmission mode (OFF) by changing the orientation direction of the liquid crystal compound by turning the voltage applied to the VA liquid crystal cell ON (20V) and OFF.

[0176] The materials used for each are listed below.

[0177] Boronic acid compound B-3

[0178]

[0179] Surfactant S-3 (The numerical value indicated for each repeating unit represents the content (mass %) of each repeating unit relative to the total number of repeating units. n is 9. The weight-average molecular weight is 11000. Ac represents an acetyl group.)

[0180]

[0181] Surfactant S-4 (The numerical value indicated for each repeating unit represents the content (mass %) of each repeating unit relative to the total number of repeating units. The weight-average molecular weight is 11,000.)

[0182]

[0183] Surfactant: BYK-356 (manufactured by BYK Corporation)

[0184] A-DPH: NK Ester A-DPH (manufactured by Shin-Nakamura Chemical Co., Ltd.) A-600: NK Ester A-600 (manufactured by Shin-Nakamura Chemical Co., Ltd.) GLM: Bremmer GLM (manufactured by NOF Corporation) ATM-35E: NK Ester ATM-35E (manufactured by Shin-Nakamura Chemical Co., Ltd.) UA-306T: UA-306T (manufactured by Kyoeisha Chemical Co., Ltd.)

[0185] <Evaluation> (Adhesion Evaluation) The obtained optical film was evaluated using the cross-cut method described in JIS-K-5600-5-6-1. Specifically, 100 grid lines were made on the surface of the optical film (protective layer side surface) at 1 mm intervals, cellophane tape (manufactured by Nichiban Co., Ltd.) was applied to the protective layer surface, peeled off, and judged according to the following criteria: A: No peeling occurred in the grid lines B: More than 90% of the grid lines were peel-free C: More than 10% of the grid lines were peel-free and less than 90% D: Less than 10% of the grid lines were peel-free

[0186] (Evaluation of Transmittance Center Axis) The transmittance center axis of the light-absorbing anisotropic layer in the obtained optical film was measured by the following method. Using AxoScan OPMF-1 (OptoScience Co., Ltd.), first, the direction of the azimuthal angle in which the transmittance center axis is tilted was detected. Then, in the direction of that azimuthal angle, the Müller matrix was measured at a wavelength of 550 nm while varying the polar angle, and the transmittance was derived. The direction with the highest transmittance (polar angle) was taken as the direction of the transmittance center axis of the light-absorbing anisotropic layer.

[0187] In each of the optical films in the examples and comparative examples, it was confirmed that the angle θ between the transmittance center axis of the light absorption anisotropy layer and the normal direction of the surface of the light absorption anisotropy layer was 0°.

[0188] (Orientation Degree Evaluation) The degree of orientation of the obtained optical film at a wavelength of 550 nm was calculated by the following method. Using an AxoScan OPMF-1 (OptoScience Co., Ltd.), the Mueller matrix at a wavelength of 550 nm was measured at each pole angle, changing the pole angle, which is the angle with respect to the normal direction of the light-absorbing anisotropy layer, in 1° increments from -70° to 70°, and the minimum transmittance (Tmin) was derived. Next, after removing the effect of surface reflection, Tm(0) was defined as the Tmin at the pole angle where Tmin was highest, and Tm(40) was defined as the Tmin in the direction where the pole angle was increased by another 40° from the pole angle with the highest Tmin. Absorbance (A) was calculated from the obtained Tm(0) and Tm(40) using the following formula, and A(0) and A(40) were calculated. A = -log(Tm) Here, Tm represents transmittance and A represents absorbance. From the calculated A(0) and A(40), the degree of orientation S at a wavelength of 550 nm is defined by the following formula. Ｐ The following criteria were used to calculate and classify the results: S Ｐ =(4.6×A(40)-A(0)) / (4.6×A(40)+2×A(0)) A: Degree of orientation S Ｐ is 0.95 or more B: Orientation degree S Ｐ C: Orientation degree S (0.90 or higher, less than 0.95) Ｐ is less than 0.90

[0189] (Brittleness) The obtained optical film was wrapped around mandrels of diameter (Φ) 2 mm and 4 mm, respectively, based on the general test method for paints described in JIS-K-5600-5-1 (1999) - flexural resistance (cylindrical mandrel method), and the occurrence of cracks was observed. A: No cracks occurred with 2 mmφ B: Cracks occurred with 2 mmφ, no cracks occurred with 4 mmφ C: Cracks occurred with 4 mmφ

[0190] (Rejection) The obtained optical films were visually inspected, and rejection was judged according to the following criteria: A: No rejection B: Rejection with a diameter of less than 5 mm occurred C: Rejection with a diameter of 5 mm or more occurred In all examples, no rejection was observed before the formation of the protective layer, and in cases where rejection occurred, it occurred when the protective layer was formed on the light-absorbing anisotropic layer.

[0191] (Heat Resistance) The obtained optical film was placed in a constant temperature and humidity chamber and held for 1000 hours under conditions of 95°C and less than 10% RH. The change in transmittance at a wavelength of 550 nm before and after holding was evaluated. An AxoScan OPMF-1 (OptoScience Co., Ltd.) was used to evaluate transmittance, and the transmittance in the polar angle 0° direction was measured. A: Transmittance change less than 1.5% B: Transmittance change 1.5% or more and less than 3.0% C: Transmittance change 3.0% or more

[0192] In the table, the "mass percentage" in the "boronic acid" column represents the content (mass%) of the compound having a boronic acid structure relative to the total solid content of the specific layer-forming composition. This value essentially corresponds to the content (mass%) of the component derived from the compound having a boronic acid structure relative to the total mass of the specific layer. In the table, the "number of functional groups" in the "(meth)acrylate" column represents the number of (meth)acryloyl groups that the (meth)acrylate has. In the table, the "(meth)acrylic equivalent" in the "(meth)acrylate" column represents the (meth)acrylic equivalent (g / eq.) of the (meth)acrylate. In other words, "(meth)acrylic equivalent" represents the acrylic equivalent of the acrylate and the methacrylic equivalent of the methacrylate.

[0193]

[0194]

[0195]

[0196]

[0197] As shown in the table, the optical film of the present invention was confirmed to exhibit the desired effects. In particular, a comparison of Examples 1 to 3 confirmed that the effect was superior when the molecular weight of the compound having a boronic acid structure was 400 or less (preferably 300 or less). Furthermore, a comparison of Examples 1 and 4 to 7 confirmed that the effect was superior when the content of the compound having a boronic acid structure relative to the total mass of the specific layer was 10 to 40% by mass (preferably 15 to 35% by mass). Furthermore, a comparison of Examples 1 and 8 to 10 confirmed that the effect was superior when the surfactant had a hydrophilic group. Furthermore, a comparison of Examples 1 and 11 to 13 confirmed that the effect was superior when a polyfunctional (meth)acrylate was used. Moreover, a comparison of Examples 1 and 11 to 13 confirmed that the effect was superior when a polyfunctional (meth)acrylate was used. Furthermore, a comparison of Examples 1 and 14 to 16 confirmed that the brittleness of the optical film was superior when the thickness of the specific layer was 3.0 μm or less. Furthermore, a comparison between Examples 1 and 20 confirmed that heat resistance improved when the protective layer was formed from a protective layer-forming composition containing a compound selected from the group consisting of polyfunctional acrylates and polyfunctional methacrylates. A comparison between Examples 21 and 22 confirmed that repelling was further suppressed when the viscosity of the polyfunctional acrylate and polyfunctional methacrylate contained in the protective layer-forming composition at 25°C was 10,000 mPa·s or higher. A comparison between Examples 22 and 23 confirmed that adhesion improved when the acrylic equivalent of the polyfunctional acrylate contained in the protective layer-forming composition was 150 g / eq. or less. This is thought to be because crosslinking was more advanced in Example 22. A comparison between Examples 23 and 26 confirmed that heat resistance improved when the molecular weight of the polyfunctional (meth)acrylate contained in the protective layer-forming composition was 2000 or less. This is thought to be because the polyfunctional (meth)acrylate penetrated more easily into the liquid crystal layer (light-absorbing anisotropic layer) in Example 23.

[0198] The light-shielding mode was evaluated when viewing the image display area of ​​the image display device from an azimuth angle of 90° (rightward) and an extreme angle of 45°, with the vertical direction of the image display area of ​​the image display device set to an azimuth angle of 0°. Compared to the image display devices fabricated in Examples 29 and 31-33, the image display devices fabricated in Examples 28 and 30 made the image easier to recognize in the light-shielding mode, and it was confirmed that the image was even easier to recognize in Example 27. It is thought that the smaller the total thickness of the optical anisotropy layer, the easier it is to recognize the image.

[0199] 10 Optical film 12 Cellulose acylate film 14 Specific layer 16 Resin layer containing polyvinyl alcohol-based resin 18 Liquid crystal layer

Claims

1. An optical film in which a cellulose acylate film, a layer formed from a composition containing a compound having a boronic acid structure and a surfactant, a resin layer containing a polyvinyl alcohol-based resin, and a liquid crystal layer are directly laminated in this order.

2. The optical film according to claim 1, wherein the composition further comprises a compound selected from the group consisting of polyfunctional acrylates and polyfunctional methacrylates.

3. The optical film according to claim 2, wherein the acrylic equivalent of the polyfunctional acrylate and the methacrylic equivalent of the polyfunctional methacrylate are each 150 g / eq. or less.

4. The optical film according to claim 1, wherein the surfactant has a hydrophilic group.

5. The optical film according to claim 1, wherein the molecular weight of the compound having the boronic acid structure is 400 or less.

6. The optical film according to claim 5, wherein the molecular weight of the compound having the boronic acid structure is 300 or less.

7. The optical film according to claim 1, wherein the content of the compound having the boronic acid structure is 10 to 40% by mass with respect to the total solid content of the composition.

8. The optical film according to claim 7, wherein the content of the compound having the boronic acid structure is 15 to 35% by mass with respect to the total solid content of the composition.

9. The optical film according to claim 1, wherein the thickness of the layer formed from the composition is 3.0 μm or less.

10. The optical film according to claim 1, wherein the liquid crystal layer has a protective layer on the side opposite to the resin layer containing the polyvinyl alcohol-based resin, the liquid crystal layer and the protective layer are directly laminated, and the protective layer is a layer formed from a protective layer-forming composition containing a compound selected from the group consisting of polyfunctional acrylates and polyfunctional methacrylates.

11. The optical film according to claim 10, wherein the acrylic equivalent of the polyfunctional acrylate and the methacrylic equivalent of the polyfunctional methacrylate contained in the protective layer forming composition are each 150 g / eq. or less.

12. The optical film according to claim 10, wherein the viscosity of the polyfunctional acrylate and the polyfunctional methacrylate contained in the protective layer forming composition is 10,000 mPa·s or more at 25°C.

13. The optical film according to claim 10, wherein the molecular weight of the polyfunctional acrylate and the polyfunctional methacrylate contained in the protective layer forming composition is 2000 or less.

14. The optical film according to claim 1, wherein the liquid crystal layer is a light-absorbing anisotropic layer containing a dichroic substance.

15. The optical film according to claim 14, wherein the angle between the transmittance center axis of the light-absorbing anisotropic layer and the normal direction of the surface of the light-absorbing anisotropic layer is 0 to 45°.

16. A display device comprising an optical film according to any one of claims 1 to 15.

Images