JP2022018120A - Optical film and its manufacturing method - Google Patents

Abstract

Kind Code: A1 A novel optical film whose optical refractive index is controlled in three-dimensional directions with respect to the entire visible light range and all viewing directions, and a method for producing the same are provided. SOLUTION: An optical film has a first retardation layer and a second retardation layer and satisfies the relationships of the following formulas (1) and (2). 0.4 ≤ Nz (450) ≤ 0.6 (1) 0.4 ≤ Nz (550) ≤ 0.6 (2) [In the formula, Nz (450) is the Nz of the optical film for light with a wavelength λ = 450 nm Nz(550) indicates the Nz coefficient of the optical film for light of wavelength λ=550 nm. ] [Selection] None

Description

The present invention relates to an optical film and a method for producing the same.

An optical film such as a polarizing plate or a retardation plate is used in a flat panel display device (FPD). The retardation plate is required to have uniform phase conversion over the entire visible light range. For example, Patent Document 1 has a horizontally oriented reverse wavelength dispersive retardation film, and Patent Document 2 has a vertically oriented reverse wavelength dispersive retardation film. The reverse wavelength dispersive phase difference film is disclosed.

Special Table 2010-537955 Gazette JP-A-2015-57646

In recent years, with the evolution of flat panel displays, there has been a demand for a clear black display from any direction. According to this, it became clear that the horizontal or vertical light wavelength dispersion control alone is not sufficient.

The present invention includes the following inventions.

[1] An optical film having a first retardation layer and a second retardation layer and satisfying the relationships of the following equations (1) and (2).
0.4 ≤ Nz (450) ≤ 0.6 (1)
0.4 ≤ Nz (550) ≤ 0.6 (2)
[In the equation, Nz (450) indicates the Nz coefficient of the optical film for light having a wavelength λ = 450 nm, and Nz (550) indicates the Nz coefficient of the optical film for light having a wavelength λ = 550 nm. The Nz coefficient Nz (λ) of the optical film with respect to light is Nz (λ) = (nx (λ) -nz (λ)) / (nx (λ) -ny (λ)).
Indicated by. nx (λ) represents the main refractive index in the direction parallel to the film plane with respect to light having a wavelength of λ (nm) in the refractive index ellipsoid formed by the optical film. In the refractive index ellipsoid formed by the optical film, ny (λ) is a refraction in a direction parallel to the film plane with respect to light having a wavelength λ (nm) and perpendicular to the direction of the nx (λ). Represents a rate.
nz (λ) represents the refractive index in the direction perpendicular to the film plane with respect to light having a wavelength of λ (nm) in the refractive index ellipsoid formed by the optical film. ]

[2] The first retardation layer is
In the refractive index ellipsoid formed by the first retardation layer, the wavelength is in the range of λ = 400 to 700 nm.
nx1 (λ)> ny1 (λ) ≒ nz1 (λ)
[In the equation, nx1 (λ) represents the main refractive index in the direction parallel to the film plane with respect to light having a wavelength of λ (nm) in the refractive index ellipsoid formed by the first retardation layer. In the refractive index ellipsoid formed by the first retardation layer, ny1 (λ) has a wavelength λ (nm) that is parallel to the film plane and orthogonal to the direction of nx1 (λ). Represents the refractive index of light. nz1 (λ) represents the refractive index in the direction perpendicular to the film plane with respect to light having a wavelength of λ (nm) in the refractive index ellipsoid formed by the first retardation layer. ]
Have a relationship with
The optical film according to the above [1], which satisfies the relationship of the following formulas (3) and (4).
Re1 (450) / Re1 (550) ≤ 1.00 (3)
1.00 ≤ Re1 (650) / Re1 (550) (4)
[In the equation, Re1 (450) is the in-plane retardation value of the first retardation layer for light having a wavelength λ = 450 nm, and Re1 (550) is the in-plane position of the first retardation layer for light having a wavelength λ = 550 nm. Re1 (650) indicates the in-plane retardation value of the first retardation layer for light having a wavelength of λ = 650 nm, and Re1 (λ) indicates the in-plane retardation value of the first retardation layer for light having a wavelength of λ nm. )teeth,
Re1 (λ) = (nx1 (λ) -ny1 (λ)) × d1
It is represented by. Here, d1 represents the thickness of the first retardation layer. ]

[3] The second retardation layer is
In the refractive index ellipsoid formed by the second retardation layer, in the wavelength range of λ = 400 to 700 nm,
nz2 (λ)> nx2 (λ) ≒ ny2 (λ)
[In the equation, nz2 (λ) represents the refractive index in the direction perpendicular to the film plane with respect to light having a wavelength of λ (nm) in the refractive index ellipsoid formed by the second retardation layer. In the refractive index ellipsoid formed by the second retardation layer, nx2 (λ) represents the maximum refractive index in the direction parallel to the film plane with respect to light having a wavelength of λ (nm). ny2 (λ) is a refractive index ellipsoid formed by the second retardation layer, with respect to light having a wavelength λ (nm) parallel to the film plane and orthogonal to the nx2 direction. Represents the refractive index. However, when nx2 (λ) = ny2 (λ), nx2 (λ) represents the refractive index in an arbitrary direction parallel to the film plane. ]
Have a relationship with
The optical film according to the above [1] or the above [2], which satisfies the relationship of the following formulas (5) and (6).
Rth2 (450) / Rth2 (550) ≤ 1.00 (5)
1.00 ≤ Rth2 (650) / Rth2 (550) (6)
[In the equation, Rth2 (450) is the phase difference value in the thickness direction for light having a wavelength λ = 450 nm, and Rth2 (550) is the phase difference value in the thickness direction for light having a wavelength λ = 550 nm. , Rth2 (650) represent the phase difference value in the thickness direction of the second retardation layer for light having a wavelength of 650 nm, respectively, and the phase difference value Rth2 in the thickness direction of the second retardation layer for light having a wavelength λ (nm). (Λ) is
Rth2 (λ) = [(nx2 (λ) + ny2 (λ)) / 2-nz2 (λ)] × d2
It is represented by. Here, in the refractive index ellipse formed by the second retardation layer, nz2 (λ) represents the main refractive index in the direction perpendicular to the film plane at the wavelength λ (nm), and ((nx2 (λ) + ny2). (Λ)) / 2) represents the average refractive index in the film plane at the wavelength λ (nm). d2 represents the thickness of the second retardation layer. ]

[4] The optical film according to any one of [1] to [3] above, wherein the first retardation layer further satisfies the relationship of the following formula (7).
120nm ≤ Re1 (550) ≤ 170nm (7)
[In the equation, Re1 (550) represents the in-plane retardation value of the first retardation layer with respect to light having a wavelength λ = 550 nm. ]

[5] The optical film according to any one of the above [1] to [4], wherein the second retardation layer further has optical characteristics represented by the formula (9).
-100nm ≤ Rth2 (550) ≤ -50nm (8)
[In the equation, Rth2 (550) represents the phase difference value in the thickness direction of the second phase difference layer with respect to light having a wavelength λ = 550 nm. ]

[6] The optical film according to any one of [1] to [5] above, which is a film composed of a coating layer formed by polymerizing a polymerizable liquid crystal in an oriented state in which a second retardation layer is oriented.

[7] The optical film according to any one of the above [1] to [6], wherein the first retardation layer is a film formed by polymerizing a polymerizable liquid crystal in an oriented state.

[8] The optical film according to any one of [1] to [7] above, wherein the second retardation layer is 5 μm or less.

[9] The optical film according to any one of [1] to [8] above, wherein the first retardation layer is 5 μm or less.

[10] The above-mentioned [1] to [9], wherein the first retardation layer and the second retardation layer are coating layers formed by mainly polymerizing the same polymerizable liquid crystal compound. Optical film.

[11] An elliptical polarizing plate with an optical compensation function having the optical film according to any one of the above [1] to [10] and a polarizing plate.

[12] The absorption axis of the polarizing plate and the slow axis of the first retardation layer have a relationship of 45 ± 5 ° or 135 ± 5 ° in the film surface, and the absorption axis of the polarizing plate and the first The elliptical polarizing plate with an optical compensation function according to the above [11], wherein the slow axis of the retardation layer and the slow axis of the second retardation layer are orthogonal to the film surface in the vertical direction.

[13] The above-mentioned [11] or [12], which is an optical laminate in which a polarizing plate, an adhesive layer, a first retardation layer, an adhesive layer, and a second retardation layer are formed in this order. Elliptical polarizing plate with optical compensation function.

[14] The above-mentioned [11] or [12], which is an optical laminate in which a polarizing plate, an adhesive layer, a second retardation layer, an adhesive layer, and a first retardation layer are formed in this order. Elliptical polarizing plate with optical compensation function.

An organic EL display device including the elliptical polarizing plate with an optical compensation function according to any one of the above [11] to [14].

The method for manufacturing an elliptical polarizing plate with an optical compensation function according to any one of the above [11] to [14], which includes all of the following steps.
(Step 1-A) A step of applying a polymerizable liquid crystal compound on a substrate on which a horizontally oriented film is formed and then polymerizing the compound in a horizontally oriented state to form a retardation layer.
(Step 1-B) A step of applying a polymerizable liquid crystal compound on a substrate on which a vertically oriented film is formed and then polymerizing the polymer in a vertically oriented state to form a second retardation layer.
(Step 2) A step of transferring the liquid crystal polymer of the first retardation layer and the liquid crystal polymer of the second retardation layer from a substrate via an adhesive and laminating them on a polarizing plate.

INDUSTRIAL APPLICABILITY According to the present invention, a novel optical film having a light refractive index controlled in a three-dimensional direction with respect to the entire visible light range and all visible directions and a method for manufacturing the same are provided. Further, the present invention provides a liquid crystal display device and an organic EL display device that enable clear display display by using this optical film.

Hereinafter, embodiments of the present invention will be described in detail. The scope of the present invention is not limited to the embodiments described here, and various modifications can be made without impairing the gist of the present invention.

The optical film of the present invention comprises a first retardation layer and a second retardation layer. The first retardation layer and the second retardation layer may be formed by a method of stretching or shrinking a polymer film, but from the viewpoint of thinning, a polymerizable liquid crystal display (hereinafter, also referred to as a polymerizable liquid crystal compound). It is preferable that the film is composed of a coating layer formed by coating and polymerizing in an oriented state.

The first retardation layer and the second retardation layer are formed by applying a composition containing a polymerizable liquid crystal compound (hereinafter, also referred to as “composition for forming a retardation layer”) onto a transparent substrate. However, it is preferable to obtain a polymer in the oriented state of the polymerizable liquid crystal compound by heating and cooling treatment, because the thickness can be reduced and the wavelength dispersion characteristics can be arbitrarily designed. Further, as will be described later, the composition for forming a retardation layer may further contain a solvent, a photopolymerization initiator, a photosensitizer, a polymerization inhibitor, a leveling agent, an adhesion improver and the like.

The first retardation layer is preferably a liquid crystal cured film cured with the polymerizable liquid crystal compound oriented horizontally with respect to the substrate surface, and the second retardation layer is based on the polymerizable liquid crystal compound. It is preferable that the liquid crystal cured film is cured in a state of being oriented in the direction perpendicular to the surface.

In the first retardation layer, it is preferable that Re1 (550), which is an in-plane retardation value for light having a wavelength of 550 nm, satisfies the optical characteristics represented by the following formula (7). The first retardation layer is Re1 (450), which is an in-plane retardation value for light having a wavelength of 450 nm, Re1 (550), which is an in-plane retardation value for light having a wavelength of 550 nm, and a surface for light having a wavelength of 650 nm. It is also preferable that Re1 (650), which is an internal phase difference value, satisfies the optical characteristics represented by the equations (3) and (4). It is more preferable that the first retardation layer satisfies the optical characteristics represented by the following formulas (7), the following formula (3) and the following formula (4).
120nm ≤ Re1 (550) ≤ 170nm ... (7)
(In the equation, Re1 (550) represents an in-plane retardation value (in-plane retardation) with respect to light having a wavelength of 550 nm in the first retardation layer.)
Re1 (450) / Re1 (550) ≤ 1.0 ... (3)
1.00 ≤ Re1 (650) / Re1 (550) ... (4)
(In the equation, Re1 (450) is the in-plane retardation value of the first retardation layer for light having a wavelength of 450 nm, and Re1 (550) is the in-plane retardation value of the first retardation layer for light having a wavelength of 550 nm. Re1 (650) represents the in-plane retardation value of the first retardation layer with respect to light having a wavelength of 650 nm.)
If the in-plane retardation value Re1 (550) of the first retardation layer exceeds the range of the equation (7), the problem that the front hue becomes red or blue may occur. A more preferable range of the in-plane retardation value is 130 nm ≦ Re1 (550) ≦ 160 nm. When the "Re1 (450) / Re1 (550)" of the first retardation layer exceeds 1.0, the light loss on the short wavelength side of the elliptical polarizing plate provided with the retardation layer becomes large. It is preferably 0.75 or more and 0.92 or less, more preferably 0.77 or more and 0.87 or less, and further preferably 0.79 or more and 0.85 or less.

The in-plane retardation value of the first retardation layer can be adjusted by the thickness of the retardation layer. Since the in-plane phase difference value is determined by the following equation (A), a desired in-plane phase difference value (Re1 (λ): in-plane phase difference value of the first phase difference layer at the wavelength λ (nm)). In order to obtain the above, the three-dimensional refractive index and the film thickness d1 may be adjusted. The thickness of the retardation layer is preferably 0.5 μm to 5 μm, more preferably 1 μm to 3 μm. The thickness of the retardation layer can be measured by an interference film thickness meter, a laser microscope or a stylus type film thickness meter. The three-dimensional refractive index depends on the molecular structure and orientation state of the polymerizable liquid crystal compound described later.
Re1 (λ) = (nx1 (λ) -ny1 (λ)) × d1 (A)
(In the equation, in the refractive index ellipse formed by the first retardation layer, there is a relationship of nx1 (λ)> ny1 (λ) ≈ nz1 (λ), and nx1 (λ) is light having a wavelength of λ (nm). Represents the principal index of refraction in the direction parallel to the film plane. Ny1 (λ) is parallel to the film plane in the refractive index ellipse formed by the first retardation layer for light of wavelength λ (nm). Yes, and represents the refractive index in the direction orthogonal to the direction of nx1 (λ). D1 represents the thickness of the first retardation layer.)

In the second retardation layer, it is preferable that Rth2 (λ), which is a retardation value in the thickness direction with respect to light having a wavelength of λ nm, satisfies the optical characteristics represented by the following formula (8). It is also preferable to satisfy the optical characteristics represented by the following formulas (5) and (6). It is more preferable that the second retardation layer satisfies the optical characteristics represented by the following formulas (8), the following formula (5) and the following formula (6).
-100nm ≤ Rth2 (550) ≤ -50nm ... (8)
(In the equation, Rth2 (550) represents the phase difference value in the thickness direction with respect to light having a wavelength of 550 nm.)
Rth2 (450) / Rth2 (550) ≤ 1.0 ... (5)
1.00 ≤ Rth2 (650) / Rth2 (550) ... (6)
(In the formula, Rth2 (450) has the same meaning as described above for light having a wavelength of 450 nm, Rth2 (550) has the same meaning as described above, and Rth2 (650) has a phase difference value in the thickness direction for light having a wavelength of 650 nm. Represent each.)
If the retardation value Rth2 (550) in the thickness direction of the second retardation layer exceeds the range of the equation (8), the problem that the orthorhombic hue becomes red or blue may occur. A more preferable range of the retardation value in the thickness direction is −95 nm ≦ Rth2 (550) ≦ −55 nm, and a more preferable range is −90 nm ≦ Rth2 (550) ≦ −60 nm. When the "Rth2 (450) / Rth2 (550)" of the second retardation layer exceeds 1.0, the light loss on the short wavelength side of the elliptical polarizing plate provided with the retardation layer becomes large. It is preferably 0.75 or more and 0.92 or less, more preferably 0.77 or more and 0.87 or less, and further preferably 0.79 or more and 0.85 or less.

The retardation value in the thickness direction of the second retardation layer can be adjusted by the thickness of the retardation layer. Since the in-plane retardation value is determined by the following equation (B), the in-plane retardation value of the second retardation layer at the desired thickness direction retardation value (Rth2 (λ): wavelength λ (nm)). ), The three-dimensional refractive index and the film thickness d2 may be adjusted. The thickness of the retardation layer is preferably 0.2 μm to 5 μm, more preferably 0.5 μm to 2 μm. The thickness of the retardation layer can be measured by an interference film thickness meter, a laser microscope or a stylus type film thickness meter. The three-dimensional refractive index depends on the molecular structure and orientation of the polymerizable liquid crystal compound described later.
Rth2 (λ) = [(nx2 (λ) + ny2 (λ)) / 2-nz2 (λ)] × d2 (B)
(In the equation, in the refractive index ellipse formed by the second retardation layer, there is a relationship of nz2 (λ)> nx2 (λ) ≈ ny2 (λ), and in the equation, nz2 (λ) is the second position. In the refractive index ellipse formed by the retardation layer, it represents the refractive index in the direction perpendicular to the film plane with respect to light having a wavelength of λ (nm). Nx2 (λ) is the refractive index ellipse formed by the second retardation layer. In the body, represents the maximum refractive index in the direction parallel to the film plane with respect to light of wavelength λ (nm). Ny2 (λ) is the refractive index elliptical body formed by the second retardation layer, in the film plane. On the other hand, it represents the refractive index for light having a wavelength λ (nm) in a direction orthogonal to the direction of nx2, which is parallel to the nx2. However, when nx2 (λ) = ny2 (λ), nx2 is represented. (Λ) represents the refractive index in an arbitrary direction parallel to the film plane, where d2 represents the thickness of the second retardation layer.)

The optical film of the present invention has a first retardation layer and a second retardation layer, and satisfies the relationship of the following formulas (1) and (2).
0.40 ≤ Nz (450) ≤ 0.60 (1)
0.40 ≤ Nz (550) ≤ 0.60 (2)
(In the equation, Nz (λ) is an Nz coefficient indicating the relationship of the three-dimensional refractive index with respect to light having a wavelength of λ (nm), and Nz (λ) = (nx (λ) -nz (λ)) / (nx ( λ) -ny (λ)). Nx (λ) represents the main refractive index in the direction parallel to the film plane with respect to light having a wavelength of λ (nm) in the refractive index ellipse formed by the optical film. .Ny (λ) is a refractive index ellipse formed by the optical film, which is parallel to the film plane with respect to light having a wavelength of λ (nm) and is orthogonal to the direction of nx (λ). Represents the refractive index. Nz (λ) represents the refractive index in the direction perpendicular to the film plane with respect to light having a wavelength of λ (nm) in the refractive index ellipse formed by the optical film.)
That is, the optical film of the present invention has a three-dimensional refractive index relationship of nx (λ)> nz (λ)> ny (λ), and the optical film has a relationship of equations (1) and (2). , It is possible to give excellent display characteristics of hue when mounted on a display. It is more preferable that Nz (λ) is 0.45 ≦ Nz (450) ≦ 0.55 and 0.45 ≦ Nz (550) ≦ 0.55, respectively. Here, Nz (450) indicates the Nz coefficient at the wavelength λ = 450 nm, and Nz (550) indicates the Nz coefficient at the wavelength λ = 550 nm.

The Nz coefficient (Nz coefficient: Nz (λ)) indicating the relationship between nx (λ), ny (λ), and nz (λ) at each wavelength λ (nm) of the optical film is calculated by the following equation.
Nz (λ) = (nx (λ) -nz (λ)) / (nx (λ) -ny (λ))
Further, when calculating the Nz coefficient of the optical film, if the front retardation value of the first retardation layer and the second retardation layer and the retardation value in the thickness direction are known, the following equation (C) ) Can also be calculated.
Nz (λ) = (Rth1 (λ) + Rth2 (λ)) / (Re1 (λ) + Re2 (λ)) +0.5 (C)
(In the equation, Re1 (λ) is the front retardation value of the first retardation layer at the wavelength λ (nm), and Re2 (λ) is the front position of the second retardation layer at the wavelength λ (nm). Rth1 (λ) is the phase difference value in the thickness direction of the first phase difference layer at the wavelength λ (nm), and Rth2 (λ) is the phase difference value of the second phase difference layer at the wavelength λ (nm). It is a phase difference value in the thickness direction.)

[Polymerizable liquid crystal]
The polymerizable liquid crystal compound is a liquid crystal compound having a polymerizable functional group, particularly a photopolymerizable functional group. The photopolymerizable functional group refers to a group that can participate in the polymerization reaction by an active radical, an acid, or the like generated from the photopolymerization initiator. Examples of the photopolymerizable functional group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxylanyl group, an oxetanyl group and the like. Of these, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxylanyl group and an oxetanyl group are preferable, and an acryloyloxy group is more preferable. The liquid crystal may be a thermotropic liquid crystal or a riotropic liquid crystal, but the thermotropic liquid crystal is preferable in that precise film thickness control is possible. Further, the phase-ordered structure of the thermotropic liquid crystal may be either a nematic liquid crystal or a smectic liquid crystal.

In the present invention, as the polymerizable liquid crystal compound, the structure of the following formula (I) is particularly preferable in terms of exhibiting the above-mentioned reverse wavelength dispersibility.

In formula (I), Ar represents a divalent aromatic group which may have a substituent. The aromatic group referred to here is a group having a cyclic structure having flatness, and the number of π electrons of the ring structure is [4n + 2] according to Hückel's law. Here, n represents an integer. When a ring structure is formed by including heteroatoms such as —N = and —S—, the case where the Hückel's rule is satisfied including the uncovalent bond electron pair on these heteroatoms and the aromaticity is included is also included. The divalent aromatic group preferably contains at least one of a nitrogen atom, an oxygen atom and a sulfur atom.
G ¹ and G ² independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group, respectively. Here, the hydrogen atom contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group is a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, and carbon. The carbon atom constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with an alkoxy group, a cyano group or a nitro group of the number 1 to 4, and is an oxygen atom or a sulfur atom. Alternatively, it may be substituted with a nitrogen atom.
L ¹ , L ² _, B ¹ and B ² are independently single-bonded or divalent linking groups, respectively.
k and l each independently represent an integer of 0 to 3, and satisfy the relationship of 1 ≦ k + l. Here, when 2 ≦ k + l, B ¹ and B ² , G ¹ and G ² may be the same as each other or may be different from each other.
E ¹ and E ² each independently represent an alkanediyl group having 1 to 17 carbon atoms, wherein the hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and the alkanediyl group may be substituted with the halogen atom. The included -CH _2- may be substituted with -O-, -S-, -Si-. P ¹ and P ² independently represent a polymerizable group or a hydrogen atom, and at least one is a polymerizable group.

G ¹ and G ² are each independently substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, preferably a 1,4-phenylenediyl group. , A 1,4-cyclohexanediyl group optionally substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group substituted 1. , 4-phenylenediyl group, unsubstituted 1,4-phenylenediyl group, or unsubstituted 1,4-trans-cyclohexanediyl group, particularly preferably unsubstituted 1,4-phenylenediyl group, or no substituted It is a substituted 1,4-trans-cyclohexandiyl group.
Further, at least one of a plurality of G ¹ and G ² present is preferably a divalent alicyclic hydrocarbon group, and at least one of G ¹ and G ² bonded to L ¹ or L ² is preferable. More preferably, it is a divalent alicyclic hydrocarbon group.

L ¹ and L ² are independent of each other, preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R ^a1 OR ^a2- , -R ^a3 COOR ^a4- , -R ^a5 . OCOR ^a6- , R ^a7 OC = OOR ^a8- , -N = N-, -CR ^c = CR ^d- , or -C≡C-. Here, R ^a1 to R ^a8 each independently represent a single bond or an alkylene group having 1 to 4 carbon atoms, and R ^c and R ^d represent an alkyl group or a hydrogen atom having 1 to 4 carbon atoms. L ¹ and L ² are independent, more preferably single bonds, -OR ^a2-1- , -CH _2- , -CH ₂ CH _2- , ^{-COOR a4-1-} , or -OCOR ^a6-1- . be. Here, R ^a2-1 , R ^a4-1 , and R ^a6-1 independently represent either single bond, -CH _2- , or -CH ₂ CH _2- . L ¹ and L ² are independent, more preferably single bond, -O-, -CH ₂ CH _2- , -COO-, -COOCH ₂ CH _2- , or -OCO-, respectively.

B ¹ and B ² are independent of each other, preferably single bond, alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R ^a9 OR ^a10- , -R ^a11 COOR ^a12- , -R ^a13 . OCOR ^a14 -or R ^a15 OC = OOR ^a16- . Here, R ^a9 to R ^a16 each independently represent a single bond or an alkylene group having 1 to 4 carbon atoms. B ¹ and B ² are independent, more preferably single-bonded, -OR ^a10-1- , -CH _2- , -CH ₂ CH _2- , ^{-COOR a12-1-} , or -OCOR ^a14-1- . be. Here, R ^a10-1 , R ^a12-1 , and R ^a14-1 independently represent either single bond, -CH _2- , or -CH ₂ CH _2- . B ¹ and B ² are independent, more preferably single bond, -O-, -CH ₂ CH _2- , -COO-, -COOCH _{2 CH 2-, -OCO-, or -OCOCH 2 CH 2- ,} Is.

From the viewpoint of expressing reverse wavelength dispersibility, k and l are preferably in the range of 2 ≦ k + l ≦ 6, preferably k + l = 4, and more preferably k = 2 and l = 2. It is more preferable that k = 2 and l = 2 because the symmetrical structure is obtained.

E ¹ and E ² are each independently preferably an alkanediyl group having 1 to 17 carbon atoms, and more preferably an alkanediyl group having 4 to 12 carbon atoms.

The polymerizable group represented by P ¹ or P ² includes an epoxy group, a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, and an oxylanyl group. , And an oxetanyl group and the like. Of these, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxylanyl group and an oxetanyl group are preferable, and an acryloyloxy group is more preferable.

Ar preferably has at least one selected from an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocycle which may have a substituent, and an electron-withdrawing group. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring and the like, and a benzene ring and a naphthalene ring are preferable. Examples of the aromatic heterocycle include a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazole ring, a triazine ring, a pyrrolin ring, an imidazole ring, and a pyrazole ring. , Thiazole ring, benzothiazole ring, thienothiazole ring, oxazole ring, benzoxazole ring, phenanthroline ring and the like. Among them, it is preferable to have a thiazole ring, a benzothiazole ring, or a benzofuran ring, and it is more preferable to have a benzothiazole group. When Ar contains a nitrogen atom, the nitrogen atom preferably has π electrons.

In the formula (I), the total number of _π electrons contained in the divalent aromatic group represented by Ar is preferably 8 or more, more preferably 10 or more, still more preferably 14 or more, and particularly preferably 14 or more. It is preferably 16 or more. Further, it is preferably 30 or less, more preferably 26 or less, and further preferably 24 or less.

Examples of the aromatic group represented by Ar include the following groups.

In the formulas (Ar-1) to (Ar-22), * indicates a connecting part, and Z ⁰ , Z ¹ and Z ² are independently hydrogen atoms, halogen atoms, and alkyl having 1 to 12 carbon atoms. Group, cyano group, nitro group, alkylsulfinyl group having 1 to 12 carbon atoms, alkylsulfonyl group having 1 to 12 carbon atoms, carboxyl group, fluoroalkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 6 carbon atoms, Alkylthio group with 1 to 12 carbon atoms, N-alkylamino group with 1 to 12 carbon atoms, N, N-dialkylamino group with 2 to 12 carbon atoms, N-alkylsulfamoyl group with 1 to 12 carbon atoms or carbon Represents an N, N-dialkylsulfamoyl group of number 2-12.

Q ¹ , Q ² and Q ³ independently represent -CR 2'R ^3'- , -S-, -NH-, -NR 2'-, -CO- or -O-, and R ^{2 ' .} And R ^{3'independently} represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

J ¹ and J ² independently represent a carbon atom or a nitrogen atom, respectively.

Y ¹ , Y ² and Y ³ each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group which may be substituted.

W ¹ and W ² independently represent a hydrogen atom, a cyano group, a methyl group or a halogen atom, and m represents an integer of 0 to 6.

Examples of the aromatic hydrocarbon group in Y ¹ , Y ² and Y ³ include an aromatic hydrocarbon group having 6 to 20 carbon atoms such as a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group and a biphenyl group, and a phenyl group. , A naphthyl group is preferable, and a phenyl group is more preferable. The aromatic heterocyclic group has 4 to 20 carbon atoms including at least one heteroatom such as a nitrogen atom such as a frill group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group and a benzothiazolyl group, an oxygen atom and a sulfur atom. Examples thereof include an aromatic heterocyclic group, and a frill group, a thienyl group, a pyridinyl group, a thiazolyl group and a benzothiazolyl group are preferable.

Y ¹ , Y ² and Y ³ may be independently substituted polycyclic aromatic hydrocarbon groups or polycyclic aromatic heterocyclic groups, respectively. The polycyclic aromatic hydrocarbon group refers to a condensed polycyclic aromatic hydrocarbon group or a group derived from an aromatic ring assembly. The polycyclic aromatic heterocyclic group refers to a fused polycyclic aromatic heterocyclic group or a group derived from an aromatic ring assembly.

It is preferable that Z ⁰ , Z ¹ and Z ² are independently hydrogen atom, halogen atom, alkyl group having 1 to 12 carbon atoms, cyano group, nitro group and alkoxy group having 1 to 12 carbon atoms, respectively. ⁰ is more preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, and a cyano group, and Z ¹ and Z ² are further preferably a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, and a cyano group.

Q ¹ , Q ² and Q ³ are preferably -NH-, -S-, -NR 2'-, and ^-O- , and R ^2'is preferably a hydrogen atom. Of these, -S-, -O-, and -NH- are particularly preferable.

Among the formulas (Ar-1) to (Ar-22), the formulas (Ar-6) and (Ar-7) are preferable from the viewpoint of molecular stability.
In formulas (Ar-16) to (Ar-22), Y ¹ may form an aromatic heterocyclic group together with the nitrogen atom to which it is attached and Z ⁰ . Examples of the aromatic heterocyclic group include those described above as the aromatic heterocycle that Ar may have. For example, a pyrrole ring, an imidazole ring, a pyrroline ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, and an indole. Examples thereof include a ring, a quinoline ring, an isoquinoline ring, a purine ring, a pyrroline ring, and the like. This aromatic heterocyclic group may have a substituent. Further, Y ¹ may be a polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group which may be substituted as described above, together with the nitrogen atom to which the Y 1 is bonded and Z ⁰ . For example, a benzofuran ring, a benzothiazole ring, a benzoxazole ring and the like can be mentioned.

The total content of the polymerizable liquid crystal compound in 100 parts by mass of the solid content of the retardation layer forming composition is usually 70 parts by mass to 99.5 parts by mass, preferably 80 parts by mass to 99 parts by mass. Parts, more preferably 80 parts by mass to 94 parts by mass, and further preferably 80 parts by mass to 90 parts by mass. When the total content is within the above range, the orientation of the obtained retardation layer tends to be high. Here, the solid content means the total amount of the components excluding the solvent from the composition.

[solvent]
As the solvent, a solvent capable of dissolving the polymerizable liquid crystal compound is preferable, and a solvent inactive for the polymerization reaction of the polymerizable liquid crystal compound is preferable.
Examples of the solvent include water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether and propylene glycol monomethyl ether and other alcohol solvents; ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate. , Γ-Butyrolactone, propylene glycol methyl ether acetate, ethyl lactate and other ester solvents; acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone and methyl isobutyl ketone and other ketone solvents; and aliphatic carbonization such as pentane, hexane and heptane. Hydrogen solvent; aromatic hydrocarbon solvent such as toluene and xylene; nitrile solvent such as acetonitrile; ether solvent such as tetrahydrofuran and dimethoxyethane; chlorine-containing solvent such as chloroform and chlorobenzene; dimethylacetamide, dimethylformamide, N-methyl- Examples thereof include amide-based solvents such as 2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone. Only one kind of these solvents may be used, or two or more kinds of these solvents may be used in combination. Of these, alcohol solvents, ester solvents, ketone solvents, chlorine-containing solvents, amide-based solvents and aromatic hydrocarbon solvents are preferable.

The content of the solvent in 100 parts by mass of the composition is preferably 50 parts by mass to 98 parts by mass, more preferably 70 parts by weight to 95 parts by weight. Therefore, the solid content in 100 parts by mass of the composition is preferably 2 parts by mass to 50 parts by mass. When the solid content of the composition is 50 parts by mass or less, the viscosity of the composition is low, so that the thickness of the retardation layer becomes substantially uniform, and the retardation layer tends to be less likely to have unevenness. The solid content can be appropriately determined in consideration of the thickness of the retardation layer to be manufactured.

<Initiator of polymerization>
The polymerization initiator is a compound that can generate a reactive species by the contribution of heat or light and initiate a polymerization reaction of a polymerizable liquid crystal display or the like. Examples of the reaction active species include active species such as radicals or cations or anions. Of these, a photopolymerization initiator that generates radicals by light irradiation is preferable from the viewpoint of easy reaction control.
Examples of the photopolymerization initiator include benzoin compounds, benzophenone compounds, benzyl ketal compounds, α-hydroxyketone compounds, α-aminoketone compounds, triazine compounds, iodonium salts and sulfonium salts. Specifically, Irgacure (registered trademark) 907, Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, Irgacure 369, Irgacure 379, Irgacure 127, Irgacure 2959, Irgacure 754, Irgacure 379EG (above, BASF Japan Co., Ltd.) , Sakeol BZ, Sakeol Z, Sakeol BEE (manufactured by Seiko Kagaku Co., Ltd.), kayacure BP100 (manufactured by Nippon Kayaku Co., Ltd.), Kayacure UVI-6992 (manufactured by Dow), ADEKA PTOMER SP- 152, ADEKA OPTMER SP-170, ADEKA PTMER N-1717, ADEKA OPTMER N-1919, ADEKA ARCULDS NCI-831, ADEKA ARCULDS NCI-930 (all manufactured by ADEKA Corporation), TAZ-A, TAZ -PP (above, manufactured by Nippon Sibel Hegner) and TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.) can be mentioned.
In the composition for forming a retardation layer, the photopolymerization initiator contained is at least one kind, and preferably one kind or two kinds.

Since the photopolymerization initiator can fully utilize the energy emitted from the light source and is excellent in productivity, the maximum absorption wavelength is preferably 300 nm to 400 nm, more preferably 300 nm to 380 nm, and above all, the α-acetophenone type. A polymerization initiator and an oxime-based photopolymerization initiator are preferable.

Examples of the α-acetophenone compound include 2-methyl-2-morpholino-1- (4-methylsulfanylphenyl) propan-1-one and 2-dimethylamino-1- (4-morpholinophenyl) -2-benzylbutane-1. -On and 2-dimethylamino-1- (4-morpholinophenyl) -2- (4-methylphenylmethyl) butane-1-one and the like, more preferably 2-methyl-2-morpholino-1- ( Examples thereof include 4-methylsulfanylphenyl) propan-1-one and 2-dimethylamino-1- (4-morpholinophenyl) -2-benzylbutane-1-one. Examples of commercially available α-acetophenone compounds include Irgacure 369, 379EG, 907 (above, manufactured by BASF Japan Ltd.) and Sequol BEE (manufactured by Seiko Kagaku Co., Ltd.).

Oxime-based photopolymerization initiators generate methyl radicals when irradiated with light. The methyl radical preferably promotes the polymerization of the polymerizable liquid crystal compound in the deep part of the retardation layer. Further, from the viewpoint of more efficiently advancing the polymerization reaction in the deep part of the retardation layer, it is preferable to use a photopolymerization initiator capable of efficiently utilizing ultraviolet rays having a wavelength of 350 nm or more. As the photopolymerization initiator capable of efficiently utilizing ultraviolet rays having a wavelength of 350 nm or more, a triazine compound and an oxime ester type carbazole compound are preferable, and an oxime ester type carbazole compound is more preferable from the viewpoint of sensitivity. Examples of the oxime ester-type carbazole compound include 1,2-octanedione, 1- [4- (phenylthio) -2- (O-benzoyloxime)], etanone, 1- [9-ethyl-6- (2-methylbenzoyl)]. ) -9H-carbazole-3-yl] -1- (O-acetyloxime) and the like. Commercially available oxime ester-type carbazole compounds include Irgacure OXE-01, Irgacure OXE-02, Irgacure OXE-03 (above, manufactured by BASF Japan Co., Ltd.), ADEKA PTOMER N-1919, and ADEKA Arklus NCI-831 (above). , Made by ADEKA CORPORATION) and the like.

The amount of the photopolymerization initiator added is usually 0.1 part by mass to 30 parts by mass, preferably 1 part by mass to 20 parts by mass, and more preferably 1 part by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. It is a mass part to 15 parts by mass. Within the above range, the reaction of the polymerizable group proceeds sufficiently, and the orientation of the polymerizable liquid crystal compound is not easily disturbed.

By blending a polymerization inhibitor, the polymerization reaction of the polymerizable liquid crystal compound can be controlled. Polymerization inhibitors include hydroquinones having substituents such as hydroquinone and alkyl ethers; catechols having substituents such as alkyl ethers such as butyl catechols; pyrogallols, 2,2,6,6-tetramethyl-1-. Radical trapping agents such as piperidinyloxy radicals; thiophenols; β-naphthylamines and β-naphthols. The content of the polymerization inhibitor is usually 0.01 to 10 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound in order to polymerize the polymerizable liquid crystal compound without disturbing the orientation of the polymerizable liquid crystal compound. Yes, preferably 0.1 to 5 parts by mass, and more preferably 0.1 to 3 parts by mass.

Furthermore, by using a sensitizer, the photopolymerization initiator can be made highly sensitive. Examples of the photosensitizer include xanthones such as xanthones and thioxanthones; anthracenes having substituents such as anthracene and alkyl ethers; phenothiazines; rubrene. Examples of the photosensitizer include xanthones such as xanthones and thioxanthones; anthracenes having substituents such as anthracene and alkyl ethers; phenothiazines; rubrene. The content of the photosensitizer is usually 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. 3 parts by mass.

[Leveling agent]
The leveling agent is an additive having a function of adjusting the fluidity of the composition and flattening the film obtained by applying the composition, and is, for example, a silicone-based or polyacrylate-based additive such as a silane coupling agent. And perfluoroalkyl-based leveling agents. Specifically, DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, FZ2123 (all manufactured by Toray Dow Corning Co., Ltd.), KP321, KP323, KP324, KP326, KP340, KP341, X22-161A, KF6001, KBM-1003, KBE-1003, KBM-303, KBM-402, KBM-403, KBE-402, KBE-403, KBM-1403, KBM-502, KBM-503, KBE- 502, KBE-503, KBM-5103, KBM-602, KBM-603, KBM-903, KBE-903, KBE-9103, KBM-573, KBM-575, KBE-585, KBM-802, KBM-802, KBM-803, KBE-846, KBE-9007 (all manufactured by Shin-Etsu Chemical Industry Co., Ltd.), TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF-4446, TSF4452, TSF4460 (all momentive performance materials) Fluorinert (registered trademark) FC-72, FC-40, FC-43, FC-3283 (all manufactured by Sumitomo 3M Co., Ltd.), Megafuck (registered trademark) ) R-08, R-30, R-90, F-410, F-411, F-443, F-445, F-470, F-477, F-479, F-482, F-483 (all manufactured by DIC Co., Ltd.), Ftop (trade name) EF301, EF303, EF351, EF352 (all manufactured by Mitsubishi Materials Electronics Co., Ltd.) , Surflon (registered trademark) S-381, S-382, S-383, S-393, SC-101, SC-105, KH-40, SA-100 (all of which are AGC Seimi Chemical (all of which). (Manufactured by Co., Ltd.), trade name E1830, E5844 (manufactured by Daikin Fine Chemical Laboratory Co., Ltd.), BM-1000, BM-1100, BYK-352, BYK-353 and BYK-361N (all trade names: BM Chemie) Made) and the like.

The content of the leveling agent in the composition for forming a retardation layer is preferably 0.01 part by mass to 5 parts by mass, and more preferably 0.05 part by mass to 3 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. .. When the content of the leveling agent is within the above range, it is easy to horizontally orient the polymerizable liquid crystal compound, and the obtained retardation layer tends to be smoother, which is preferable. The composition for forming a retardation layer may contain two or more kinds of leveling agents.

[Base material]
Examples of the base material include a glass base material and a film base material, and a film base material is preferable from the viewpoint of processability, and a long roll-shaped film is more preferable because it can be continuously produced. Examples of the resin constituting the film substrate include polyolefins such as polyethylene, polypropylene, and norbornene-based polymers; cyclic olefin-based resins; polyvinyl alcohol; polyethylene terephthalates; polymethacrylic acid esters; polyacrylic acid esters; triacetyl cellulose and diacetyl cellulose. And plastics such as cellulose esters such as cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfones; polyethersulfones; polyether ketones; polyphenylene sulfides and polyphenylene oxides;
Examples of commercially available cellulose ester base materials include "Fujitac Film" (manufactured by Fuji Photo Film Co., Ltd.); "KC8UX2M", "KC8UY" and "KC4UY" (manufactured by Konica Minolta Opto Co., Ltd.).
Commercially available cyclic olefin resins include "Topas" (registered trademark) (Ticona (Germany)), "Arton" (registered trademark) (JSR Corporation), "ZEONOR" (registered trademark), and the like. Examples thereof include "ZEONEX" (registered trademark) (above, manufactured by Nippon Zeon Corporation) and "APEL" (registered trademark) (manufactured by Mitsui Chemicals, Inc.). Such a cyclic olefin resin can be formed into a film by a known means such as a solvent casting method and a melt extrusion method to form a base material. A commercially available cyclic olefin resin base material can also be used. Commercially available cyclic olefin resin base materials include "Scina" (registered trademark), "SCA40" (registered trademark) (all manufactured by Sekisui Chemical Co., Ltd.), and "Zeonoa Film" (registered trademark) (manufactured by Optes Co., Ltd.). ) And "Arton Film" (registered trademark) (manufactured by JSR Corporation).
The thickness of the base material is preferably thin in that it has a mass that can be handled practically, but if it is too thin, the strength is lowered and the processability tends to be inferior. The thickness of the base material is usually 5 μm to 300 μm, preferably 20 μm to 200 μm. Further, by peeling off the base material and transferring only the polymer in the oriented state of the polymerizable liquid crystal compound, a further thinning effect can be obtained.

[Alignment film]
It is preferable that an alignment film is formed on the surface of the base material on which the composition for forming a retardation layer is applied. The alignment film has an orientation regulating force for orienting the polymerizable liquid crystal compound in a desired direction.

The alignment film has solvent resistance that does not dissolve when the composition for forming a retardation layer is applied, and also has heat resistance in heat treatment for removing the solvent and aligning the polymerizable liquid crystal compound described later. preferable.

Such an alignment film facilitates the orientation of the polymerizable liquid crystal compound. In addition, various orientations such as vertical orientation, horizontal orientation, hybrid orientation, and inclined orientation can be controlled depending on the type of alignment film, rubbing conditions, and light irradiation conditions.

As the alignment film forming the first retardation layer, an alignment film showing an orientation regulating force in the horizontal direction is applied. Examples of such a horizontal alignment film include a rubbing alignment film, a light alignment film, and a grub alignment film having an uneven pattern or a plurality of grooves on the surface. When applied to a long roll film, a photoalignment film is preferable because the orientation direction can be easily controlled.

An oriented polymer can be used for the rubbing alignment film. Examples of the oriented polymer include polyamides and gelatins having an amide bond, polyimide having an imide bond and its hydrolyzate polyamic acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, polyoxazole, polyethyleneimine, and polystyrene. , Polyvinylpyrrolidone, polyacrylic acid and polyacrylic acid esters. Two or more oriented polymers may be combined.

The rubbing alignment film is usually formed by applying a composition in which an orientation polymer is dissolved in a solvent (hereinafter, also referred to as an orientation polymer composition) to a substrate, removing the solvent to form a coating film, and then forming the coating film. Orientation control force can be imparted by rubbing.

The concentration of the oriented polymer in the oriented polymer composition may be within the range in which the oriented polymer is completely dissolved in the solvent. The content of the oriented polymer with respect to the oriented polymer composition is preferably 0.1 to 20% by mass, more preferably 0.1 to 10% by mass.

Oriented polymer compositions are available on the market. Examples of commercially available oriented polymer compositions include Sunever (registered trademark, manufactured by Nissan Chemical Industries, Ltd.), Optomer (registered trademark, manufactured by JSR Corporation) and the like.

Examples of the method of applying the oriented polymer composition to the base material include the same method as the method of applying the retardation layer forming composition described later to the base material. Examples of the method for removing the solvent contained in the oriented polymer composition include a natural drying method, a ventilation drying method, a heat drying method and a vacuum drying method.

As a method of the rubbing treatment, for example, a method of bringing the coating film into contact with a rubbing roll on which a rubbing cloth is wound and rotating can be mentioned. If masking is performed during the rubbing process, it is possible to form a plurality of regions (patterns) having different orientation directions on the alignment film.

The photoalignment film is usually formed by applying a composition for forming a photoalignment film containing a polymer or monomer having a photoreactive group and a solvent to a substrate, removing the solvent, and then irradiating the substrate with polarized light (preferably polarized UV). It can be obtained by. The photoalignment film can arbitrarily control the direction of the orientation regulating force by selecting the polarization direction of the polarized light to be irradiated.

A photoreactive group is a group that produces an orientation ability when irradiated with light. Specific examples thereof include groups involved in photoreactions that are the origin of orientation abilities such as molecular orientation-induced reactions, isomerization reactions, photodimerization reactions, photocrosslinking reactions, and photodecomposition reactions caused by light irradiation. As the photoreactive group, an unsaturated bond, particularly a group having a double bond is preferable, and a carbon-carbon double bond (C = C bond), a carbon-nitrogen double bond (C = N bond), and a nitrogen-nitrogen bond are preferable. Groups having at least one selected from the group consisting of a double bond (N = N bond) and a carbon-oxygen double bond (C = O bond) are particularly preferred.

Examples of the photoreactive group having a C = C bond include a vinyl group, a polyene group, a stilbene group, a stillbazole group, a stillvazolium group, a chalcone group and a cinnamoyl group. Examples of the photoreactive group having a C = N bond include a group having a structure such as an aromatic Schiff base and an aromatic hydrazone. Examples of the photoreactive group having an N = N bond include an azobenzene group, an azonaphthalene group, an aromatic heterocyclic azo group, a bisazo group, a formazan group, and a group having an azoxybenzene structure. Examples of the photoreactive group having a C = O bond include a benzophenone group, a coumarin group, an anthraquinone group and a maleimide group. These groups may have substituents such as an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group and an alkyl halide group.

Groups involved in the photodimerization reaction or the photocrosslinking reaction are preferable because they have excellent orientation. Among them, a photoreactive group involved in a photodimerization reaction is preferable, and a cinnamoyl group is easy to obtain because a photoalignment film having a relatively small amount of polarization irradiation required for orientation and excellent thermal stability and temporal stability can be easily obtained. And chalcone groups are preferred. As the polymer having a photoreactive group, a polymer having a cinnamoyl group having a cinnamic acid structure or a cinnamic acid ester structure at the end of the side chain of the polymer is particularly preferable.

The content of the polymer or monomer having a photoreactive group in the composition for forming a photo-alignment film can be adjusted by the type of the polymer or the monomer and the thickness of the target photo-alignment film, and is at least 0.2% by mass or more. It is preferable to use the above method, and the range of 0.3 to 10% by mass is more preferable.

Examples of the method of applying the composition for forming a photoalignment film to the substrate include the same method as the method of applying the composition for forming a retardation layer described later to the substrate. Examples of the method for removing the solvent from the applied composition for forming a photoalignment film include the same method as the method for removing the solvent from the oriented polymer composition.

In order to irradiate the polarized light, even in the form of directly irradiating the composition for forming a photoalignment film coated on the substrate with the solvent removed, the polarized light is irradiated from the substrate side and the polarization is used as the base. It may be in the form of penetrating the material and irradiating it. Further, it is preferable that the polarized light is substantially parallel light. The wavelength of the polarized light to be irradiated is preferably in the wavelength range in which the photoreactive group of the polymer or monomer having a photoreactive group can absorb light energy. Specifically, UV (ultraviolet rays) having a wavelength in the range of 250 nm to 400 nm is particularly preferable. Examples of the light source for irradiating the polarized light include a xenon lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, an ultraviolet light laser such as KrF and ArF, and the like. Of these, high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps are preferable because they have a high emission intensity of ultraviolet rays having a wavelength of 313 nm. Polarized UV can be irradiated by irradiating the light from the light source through an appropriate polarizing element. Examples of the polarizing element include a polarizing filter, a polarizing prism such as a Gran Thomson, and a Gran Tailor, and a wire grid. Of these, a wire grid type polarizing element is preferable from the viewpoint of increasing the area and resistance to heat.

If masking is performed during rubbing or polarization irradiation, it is possible to form a plurality of regions (patterns) in which the directions of liquid crystal orientation are different.

The groove alignment film is a film having an uneven pattern or a plurality of grooves on the surface of the film. When the polymerizable liquid crystal compound is applied to a film having a plurality of linear grubs arranged at equal intervals, the liquid crystal molecules are oriented in the direction along the groove.
As a method of obtaining a grub alignment film, a method of forming an uneven pattern by performing exposure and rinsing treatment after exposure through an exposure mask having a pattern-shaped slit on the surface of the photosensitive polyimide film, and a plate having a groove on the surface. A method of forming a layer of UV-curable resin before curing on a master plate, transferring the resin layer to a substrate and then curing, and a plurality of films of UV-curable resin before curing formed on the substrate. Examples thereof include a method in which a roll-shaped master having a groove is pressed to form irregularities and then cured.

The thickness of the alignment film for forming the first retardation layer is usually in the range of 10 to 10000 nm, preferably in the range of 10 to 1000 nm, and more preferably in the range of 50 to 500 nm.

As the alignment film forming the second retardation layer, an alignment film having an orientation regulating force in the vertical direction (hereinafter, also referred to as a vertical alignment film) is applied. As the vertically oriented film, it is preferable to apply a material that lowers the surface tension of the substrate surface. Examples of such a material include the above-mentioned oriented polymer, a fluoropolymer such as perfluoroalkyl, a polyimide compound, a silane compound, and a polysiloxane compound obtained by a condensation reaction thereof. Silane compounds are preferred because they tend to reduce surface tension.

As the silane compound, a silicone type such as the above-mentioned silane coupling agent can be preferably applied. For example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, N- (2-). Aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glyce Sidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercapto Examples thereof include propyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, and 3-glycidoxypropylethoxydimethylsilane. Two or more kinds of silane compounds may be used.

The silane compound may be a silicone monomer type or a type silicone oligomer (polymer) type. When the silicone oligomer is shown in the form of a (monomer)-(monomer) copolymer, for example, the following can be mentioned.

3-Mercaptopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-mercaptopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-mercaptopropyltriethoxysilane-tetramethoxysilane copolymer, and 3-mercaptopropyltriethoxysilane-tetraethoxy. Copolymers containing mercaptopropyl groups, such as silane copolymers;

Mercaptomethyl groups such as mercaptomethyltrimethoxysilane-tetramethoxysilane copolymer, mercaptomethyltrimethoxysilane-tetraethoxysilane copolymer, mercaptomethyltriethoxysilane-tetramethoxysilane copolymer, and mercaptomethyltriethoxysilane-tetraethoxysilane copolymer. Containing copolymer;

3-Methacloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-methacryloxypropyltriethoxysilane-tetramethoxysilane copolymer, 3-methacryloxypropyltriethoxysilane -Tetraethoxysilane copolymer, 3-methacryloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-methacryloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-methacryloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer, and Copolymers containing a methacryloyloxypropyl group, such as 3-methacryloxyylopropylmethyldiethoxysilane-tetraethoxysilane copolymer;

3-Acryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-acryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropyltriethoxysilane -Tetraethoxysilane copolymer, 3-acryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-acryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer, and Copolymers containing acryloyloxypropyl groups, such as 3-acryloyloxypropylmethyldiethoxysilane-tetraethoxysilane copolymers;

Vinyltrimethoxysilane-tetramethoxysilane copolymer, vinyltrimethoxysilane-tetraethoxysilane copolymer, vinyltriethoxysilane-tetramethoxysilane copolymer, vinyltriethoxysilane-tetraethoxysilane copolymer, vinylmethyldimethoxysilane-tetramethoxysilane copolymer, Vinyl group-containing copolymers such as vinylmethyldimethoxysilane-tetraethoxysilane copolymer, vinylmethyldiethoxysilane-tetramethoxysilane copolymer, and vinylmethyldiethoxysilane-tetraethoxysilane copolymer;

3-Aminopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-aminopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-aminopropyltriethoxysilane-tetramethoxysilane copolymer, 3-aminopropyltriethoxysilane-tetraethoxysilane Copolymer, 3-aminopropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-aminopropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-aminopropylmethyldiethoxysilane-tetramethoxysilane copolymer, and 3-aminopropylmethyldiethoxy Amino group-containing copolymers such as silane-tetraethoxysilane copolymers.

Of these, a silane compound having an alkyl group at the molecular terminal is preferable, and a silane compound having an alkyl group having 6 to 20 carbon atoms is more preferable. Since these silane compounds are liquid in many cases, they may be applied to the base material as they are, or may be dissolved in a solvent and applied to the base material. Further, it may be dissolved in a solvent and applied to the substrate together with various polymers as a binder.

Examples of the method of applying the vertically oriented film to the base material include the same method as the method of applying the retardation layer forming composition described later to the base material. Examples of the method for removing the solvent from the applied composition for forming a photoalignment film include the same method as the method for removing the solvent from the oriented polymer composition.

The thickness of the alignment film for forming the second retardation layer is usually in the range of 10 to 10000 nm, preferably in the range of 50 to 5000 nm, and more preferably in the range of 100 to 500 nm.

<< Manufacturing method of retardation layer >>
<Application of composition for forming a retardation layer>
A retardation layer can be formed by applying the composition for forming a retardation layer onto the base material or the alignment film. As a method of applying the composition for forming a retardation layer on a substrate, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a CAP coating method, a slit coating method, a microgravure method, a die coating method, and an inkjet method. And so on. Further, a method of applying using a coater such as a dip coater, a bar coater, or a spin coater can also be mentioned. Among them, in the case of continuous coating in the Roll to Roll format, the coating method by the microgravure method, the inkjet method, the slit coating method, or the die coating method is preferable, and in the case of coating on a single-wafer substrate such as glass, the uniformity is achieved. High spin coating method is preferred.

<Drying of composition for forming a retardation layer>
Examples of the drying method for removing the solvent contained in the composition for forming a retardation layer include natural drying, ventilation drying, heat drying, vacuum drying, and a method in which these are combined. Of these, natural drying or heat drying is preferable. The drying temperature is preferably in the range of 0 to 200 ° C, more preferably in the range of 20 to 150 ° C, and even more preferably in the range of 50 to 130 ° C. The drying time is preferably 10 seconds to 20 minutes, more preferably 30 seconds to 10 minutes. The composition for forming a photoalignment film and the orientation polymer composition can be dried in the same manner.

<Polymerization of polymerizable liquid crystal compounds>
Photopolymerization is preferable as a method for polymerizing a polymerizable liquid crystal compound. Photopolymerization is carried out by irradiating a laminate in which a composition for forming a retardation layer containing a polymerizable liquid crystal compound is applied on a substrate or an alignment film with active energy rays. The active energy rays to be irradiated include the type of the polymerizable liquid crystal compound contained in the dry film (particularly, the type of the photopolymerizable functional group of the polymerizable liquid crystal compound), and the photopolymerization initiator when the photopolymerization initiator is contained. It is appropriately selected according to the type of the polymer and the amount thereof. Specific examples thereof include one or more types of light selected from the group consisting of visible light, ultraviolet light, infrared light, X-ray, α-ray, β-ray, and γ-ray. Among them, ultraviolet light is preferable because it is easy to control the progress of the polymerization reaction and it is possible to use a photopolymerization apparatus widely used in the art, so that polymerization can be carried out by ultraviolet light. It is preferable to select the type of the sex liquid crystal compound.

Examples of the light source of the active energy ray include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a tungsten lamp, a gallium lamp, an excima laser, and a wavelength range. Examples thereof include LED light sources that emit light of 380 to 440 nm, chemical lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, and the like.

The ultraviolet irradiation intensity is usually 10 mW / cm ² to 3,000 mW / cm ² . The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activating the cationic polymerization initiator or the radical polymerization initiator. The time for irradiating light is usually 0.1 seconds to 10 minutes, preferably 0.1 seconds to 5 minutes, more preferably 0.1 seconds to 3 minutes, still more preferably 0.1 seconds. ~ 1 minute. When irradiated once or multiple times with such an ultraviolet irradiation intensity, the integrated light amount is 10 mJ / cm ² to 3,000 mJ / cm ² , preferably 50 mJ / cm ² to 2,000 mJ / cm ² , and more preferably 100 mJ. It is / cm ² to 1,000 mJ / cm ² . When the integrated light amount is less than this range, the polymerizable liquid crystal compound may not be sufficiently cured and good transferability may not be obtained. On the contrary, when the integrated light amount is equal to or more than this range, the optical film including the retardation layer may be colored.

[Polarizer]
The elliptical polarizing plate of the present invention is configured to include the polarizing plate and the optical film of the present invention. For example, the polarizing plate and the optical film of the present invention are bonded together via an adhesive, an adhesive layer, or the like. Thereby, the elliptical polarizing plate of the present invention can be obtained.
In one embodiment of the present invention, when the polarizing plate and the optical film of the present invention are laminated, the slow axis (optical axis) of the first retardation layer and the absorption axis of the polarizing plate are substantially 45 °. It is preferable to stack them so as to be. By laminating the slow axis (optical axis) of the optical film of the present invention and the absorption axis of the polarizing plate at substantially 45 °, the function as a circular polarizing plate can be obtained. It should be noted that substantially 45 ° is usually in the range of 45 ± 5 °.

The polarizing plate is composed of a polarizing element having a polarizing function. Examples of the splitter include a stretched film on which a dye having absorption anisotropy is adsorbed, and a film in which a dye having absorption anisotropy is applied and oriented. Examples of the dye having absorption anisotropy include a dichroic dye.

The stretched film on which the dye having absorption anisotropy is adsorbed is usually obtained by dyeing the polyvinyl alcohol-based resin film with a dichroic dye in the step of uniaxially stretching the polyvinyl alcohol-based resin film. It is produced through a step of adsorbing, a step of treating a polyvinyl alcohol-based resin film on which a dichroic dye is adsorbed with an aqueous boric acid solution, and a step of washing with water after the treatment with the aqueous boric acid solution. A polarizing plate can be obtained by laminating the polarizing element thus obtained and the transparent protective film. Examples of the dichroic dye include iodine and a dichroic organic dye. Examples of the bicolor organic dye include a bicolor direct dye composed of a disuazo compound such as CI DIRECT RED 39, and a bicolor direct dye composed of a compound such as trisazo and tetrakisazo. As described above, the thickness of the substituent obtained by uniaxial stretching, dyeing with a dichroic dye, boric acid treatment, washing with water and drying on a polyvinyl alcohol-based resin film is preferably 5 μm to 40 μm.

[Adhesive]
Examples of the adhesive for adhering the polarizing plate to the optical film of the present invention or the optical film of the present invention and the display device include a pressure-sensitive adhesive, a dry solidification type adhesive, and a chemical reaction type adhesive. Examples of the chemical reaction type adhesive include an active energy ray-curable adhesive. As the adhesive between the polarizing plate and the optical film of the present invention, an adhesive layer formed of a pressure-sensitive adhesive, a dry solidification type adhesive, and an active energy ray-curable adhesive is preferable, and the adhesive layer of the present invention is preferable. As the adhesive adhesive between the optical film and the display device, a pressure-sensitive adhesive or an active energy ray-curable adhesive is preferable.

The pressure-sensitive pressure-sensitive adhesive usually contains a polymer and may contain a solvent.
Examples of the polymer include acrylic polymers, silicone polymers, polyesters, polyurethanes, and polyethers. Among them, the acrylic pressure-sensitive adhesive containing an acrylic polymer has excellent optical transparency, moderate wettability and cohesive force, excellent adhesiveness, and high weather resistance and heat resistance, and is heated. It is preferable because it is unlikely to float or peel off under humid conditions.

As the acrylic polymer, the alkyl group of the ester moiety is an alkyl group having 1 to 20 carbon atoms such as a methyl group, an ethyl group or a butyl group (meth) acrylate (hereinafter, acrylate and methacrylate are collectively referred to as (meth) acrylate). Acrylic acid and methacrylic acid may be collectively referred to as (meth) acrylic acid), and have functional groups such as (meth) acrylic acid and hydroxyethyl (meth) acrylate (meth). A copolymer with an acrylic monomer is preferable.

The pressure-sensitive pressure-sensitive adhesive containing such a copolymer has excellent adhesiveness, and even when it is removed after being attached to a display device, it can be removed relatively easily without causing adhesive residue on the display device. Is preferable because it is possible. The glass transition temperature of the acrylic polymer is preferably 25 ° C. or lower, more preferably 0 ° C. or lower. The mass average molecular weight of such an acrylic polymer is preferably 100,000 or more.

Examples of the solvent include the solvents mentioned as the solvent. The pressure-sensitive pressure-sensitive adhesive may contain a light diffusing agent. The light diffusing agent is an additive that imparts light diffusing property to the pressure-sensitive adhesive, and may be fine particles having a refractive index different from that of the polymer contained in the pressure-sensitive adhesive. Examples of the light diffusing agent include fine particles made of an inorganic compound and fine particles made of an organic compound (polymer). Most of the polymers contained in the adhesive as an active ingredient, including acrylic polymers, have a refractive index of about 1.4 to 1.6, so that the light diffusing agent having a refractive index of 1.2 to 1.8 It is preferable to select an appropriate one. The difference in refractive index between the polymer contained in the pressure-sensitive adhesive as an active ingredient and the light diffusing agent is usually 0.01 or more, and is preferably 0.01 to 0.2 from the viewpoint of brightness and displayability of the display device. The fine particles used as the light diffusing agent are preferably spherical fine particles, which are also close to monodisperse, and more preferably fine particles having an average particle size of 2 μm to 6 μm. The index of refraction is measured by a common minimum argument method or an Abbe refractometer.
Examples of the fine particles made of the inorganic compound include aluminum oxide (refractive index 1.76) and silicon oxide (refractive index 1.45). The fine particles made of an organic compound (polymer) include melamine beads (refractive index 1.57), polymethyl methacrylate beads (refractive index 1.49), and methyl methacrylate / styrene copolymer resin beads (refractive index 1.50). ~ 1.59), Polycarbonate beads (refractive index 1.55), polyethylene beads (refractive index 1.53), polystyrene beads (refractive index 1.6), polyvinyl chloride beads (refractive index 1.46), and silicone. Examples thereof include resin beads (refractive index 1.46). The content of the light diffusing agent is usually 3 parts by mass to 30 parts by mass with respect to 100 parts by mass of the polymer.
The thickness of the pressure-sensitive pressure-sensitive adhesive is determined according to its adhesion and the like, and is not particularly limited, but is usually 1 μm to 40 μm. From the viewpoint of workability, durability and the like, the thickness is preferably 3 μm to 25 μm, more preferably 5 μm to 20 μm. By setting the thickness of the adhesive layer formed from the adhesive to 5 μm to 20 μm, the brightness of the display device when viewed from the front or when viewed from an angle is maintained, and bleeding or blurring of the displayed image is eliminated. It can be made less likely to occur.

[Dry solidified adhesive]
The dry solidifying adhesive may contain a solvent.
The dry solidification type adhesive contains a polymer of a monomer having a protonic functional group such as a hydroxyl group, a carboxyl group or an amino group and an ethylenically unsaturated group as a main component, or a urethane resin as a main component, and further has a multivalent value. Examples thereof include compositions containing a cross-linking agent such as an aldehyde, an epoxy compound, an epoxy resin, a melamine compound, a zirconia compound, and a zinc compound, or a curable compound. Examples of the polymer of the monomer having a protonic functional group such as a hydroxyl group, a carboxyl group or an amino group and an ethylenically unsaturated group include ethylene-maleic acid copolymer, itaconic acid copolymer, acrylic acid copolymer and acrylamide. Examples thereof include a copolymer, a saponified product of polyvinyl acetate, and a polyvinyl alcohol-based resin.

Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol, partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, and amino group-modified polyvinyl alcohol. Can be mentioned. The content of the polyvinyl alcohol-based resin in the water-based adhesive is usually 1 part by mass to 10 parts by mass, preferably 1 part by mass to 5 parts by mass with respect to 100 parts by mass of water.

Examples of the urethane resin include polyester ionomer type urethane resin and the like. The polyester-based ionomer type urethane resin referred to here is a urethane resin having a polyester skeleton, in which a small amount of an ionic component (hydrophilic component) is introduced. Since the ionomer type urethane resin is emulsified in water to form an emulsion without using an emulsifier, it can be used as a water-based adhesive. When a polyester ionomer type urethane resin is used, it is effective to add a water-soluble epoxy compound as a cross-linking agent.

Examples of the epoxy resin include a polyamide epoxy resin obtained by reacting a polyamide polyamine obtained by reacting a polyalkylene polyamine such as diethylenetriamine or triethylenetetramine with a dicarboxylic acid such as adipic acid with epichlorohydrin. Commercially available products of the polyamide epoxy resin include "Smiley's Resin (registered trademark) 650", "Smiley's Resin 675" (all manufactured by Sumika Chemtex Co., Ltd.), and "WS-525" (manufactured by Nippon PMC Co., Ltd.). And so on. When the epoxy resin is blended, the addition amount thereof is usually 1 part by mass to 100 parts by mass, preferably 1 part by mass to 50 parts by mass with respect to 100 parts by mass of the polyvinyl alcohol-based resin.

The thickness of the adhesive layer formed from the dry solidified adhesive is usually 0.001 μm to 5 μm, preferably 0.01 μm to 2 μm, and more preferably 0.01 μm to 0.5 μm. be. If the adhesive layer formed from the dry solidified adhesive is too thick, the optically anisotropic layer tends to have a poor appearance.

[Active energy ray-curable adhesive]
The active energy ray-curable adhesive may contain a solvent. The active energy ray-curable adhesive is an adhesive that cures by being irradiated with active energy rays.
Examples of the active energy ray-curable adhesive include a cationically polymerizable adhesive containing an epoxy compound and a cationic polymerization initiator, a radically polymerizable adhesive containing an acrylic curing component and a radical polymerization initiator, and an epoxy compound. It contains both a cationically polymerizable curing component such as, and a radically polymerizable curing component such as an acrylic compound, and further contains an adhesive containing a cationic polymerization initiator and a radical polymerization initiator, and these polymerization initiators. Examples thereof include an adhesive that is cured by irradiating an electron beam without using it.

Among them, radical-polymerizable active energy ray-curable adhesives containing an acrylic curing component and a radical polymerization initiator, and cationically polymerizable active energy ray-curable adhesives containing an epoxy compound and a cationic polymerization initiator are available. preferable. Examples of the acrylic curing component include (meth) acrylates such as methyl (meth) acrylate and hydroxyethyl (meth) acrylate, and (meth) acrylic acid. The active energy ray-curable adhesive containing an epoxy compound may further contain a compound other than the epoxy compound. Examples of the compound other than the epoxy compound include an oxetane compound and an acrylic compound.
Examples of the radical polymerization initiator include the above-mentioned photopolymerization initiator. Commercially available cationic polymerization initiators include "Kayarad" (registered trademark) series (manufactured by Nippon Kayaku Co., Ltd.), "Cyracure UVI" series (manufactured by Dow Chemical Co., Ltd.), and "CPI" series (manufactured by Sun Appro Co., Ltd.). "TAZ", "BBI" and "DTS" (manufactured by Midori Chemical Co., Ltd.), "ADEKA PTOMER" series (manufactured by ADEKA Corporation), "RHODORSIL" (registered trademark) (manufactured by Rhodia Co., Ltd.), etc. Be done. The content of the radical polymerization initiator and the cationic polymerization initiator is usually 0.5 parts by mass to 20 parts by mass, preferably 1 part by mass to 15 parts by mass with respect to 100 parts by mass of the active energy ray-curable adhesive. It is a department.

The active energy ray-curable adhesive further contains an ion trapping agent, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow conditioner, a plasticizer, an antifoaming agent and the like. You may.

As used herein, an active energy ray is defined as an energy ray capable of decomposing a compound that generates an active species to generate an active species. Examples of such active energy rays include visible light, ultraviolet rays, infrared rays, X-rays, α rays, β rays, γ rays and electron beams, and ultraviolet rays and electron beams are preferable. Preferred ultraviolet irradiation conditions are the same as the polymerization of the above-mentioned polymerizable liquid crystal compound.

[Display device]
The present invention can provide a display device including the optical film of the present invention as one of the embodiments. Further, the display device may include an elliptical polarizing plate according to the embodiment.
The display device is a device having a display mechanism, and includes a light emitting element or a light emitting device as a light emitting source. Display devices include liquid crystal display devices, organic electroluminescence (EL) display devices, inorganic electroluminescence (EL) display devices, touch panel display devices, electron emission display devices (electric field emission display devices (FED, etc.), surface electric field emission display devices). (SED)), electronic paper (display device using electronic ink or electrophoretic element), plasma display device, projection type display device (grating light valve (GLV) display device, display device having a digital micromirror device (DMD)). Etc.) and piezoelectric ceramic displays and the like. The liquid crystal display device includes any of a transmissive liquid crystal display device, a semi-transmissive liquid crystal display device, a reflective liquid crystal display device, a direct-view liquid crystal display device, a projection type liquid crystal display device, and the like. These display devices may be display devices that display two-dimensional images, or may be stereoscopic display devices that display three-dimensional images. In particular, an organic EL display device and a touch panel display device are preferable as the display device including the optical film and the polarizing plate according to the present invention.

Hereinafter, the present invention will be described in more detail with reference to Examples. In addition, "%" and "part" in an example mean mass% and mass part unless otherwise specified. Moreover, the polymer film, the apparatus and the measuring method used in the following Examples are as follows.

-ZF-14 manufactured by Nippon Zeon Corporation was used as the cycloolefin polymer (COP) film.
-AGF-B10 manufactured by Kasuga Electric Works Ltd. was used as the corona processing apparatus.
The corona treatment was performed once using the above corona treatment device under the conditions of an output of 0.3 kW and a processing speed of 3 m / min.
-As the polarized UV irradiation device, SPOT CURE SP-9 with a polarizing element manufactured by Ushio, Inc. was used.
-For the high-pressure mercury lamp, Unicure VB-15201BY-A manufactured by Ushio, Inc. was used.
The phase difference value Re (λ) in the in-plane direction was measured using KOBRA-WPR manufactured by Oji Measuring Instruments Co., Ltd.
-The phase difference value Rth (λ) in the thickness direction and the film thickness were measured using an ellipsometer M-220 manufactured by JASCO Corporation.

[Preparation of alignment film composition for formation of first retardation layer]
The first step was to mix 5 parts (weight average molecular weight: 30,000) of a photo-oriented material having the following structure and 95 parts of cyclopentanone (solvent) as components, and stir the obtained mixture at 80 ° C. for 1 hour. An alignment film composition for forming a retardation layer was obtained.

[Preparation of alignment film composition for formation of second retardation layer]
A silane coupling agent KBE-9103 manufactured by Shin-Etsu Chemical Co., Ltd. is dissolved in a mixed solvent in which ethanol and water are mixed at a ratio of 9: 1 (weight ratio) to form a second retardation layer having a solid content of 1%. Alignment film composition for use was obtained.

[Preparation of first and second retardation layer forming compositions (compositions I to IV)]
For the mixture of the polymerizable liquid crystal compound A and the polymerizable liquid crystal compound B described below, 0.1 part of a leveling agent (F-556; manufactured by DIC Corporation) and a polymerization initiator 2-dimethylamino-2- Six parts of benzyl-1- (4-morpholinophenyl) butane-1-one (Irgacure 369 (Irg369); manufactured by BASF Japan Co., Ltd.) were added.
Further, N-methyl-2-pyrrolidone (NMP) is added as a solvent so that the solid content concentration becomes 13%, and the mixture is stirred at 80 ° C. for 1 hour to form the first and second retardation layers. The composition was obtained. The mixture ratios of the polymerizable liquid crystal compound A and the polymerizable liquid crystal compound B are added as shown in Table 1 according to the target wavelength dispersion value α, and the names of the respective compositions are shown in Table 1. As described.

※重合性液晶化合物Ａ、及びＢの比率は、重合性液晶化合物総量に対する比率とする。

* The ratio of the polymerizable liquid crystal compounds A and B is the ratio to the total amount of the polymerizable liquid crystal compound.

The polymerizable liquid crystal compound A was produced by the method described in JP-A-2010-31223. Further, the polymerizable liquid crystal compound B was produced according to the method described in JP-A-2009-173893. The molecular structure of each is shown below.

Polymerizable liquid crystal compound A

Polymerizable liquid crystal compound B

[Preparation of liquid crystal composition for forming first and second retardation layers (Composition V)]
To the liquid crystal compound LC242: Palocolor LC242 (registered trademark of BASF) described below, 0.1 part of the leveling agent F-556 and 3 parts of the polymerization initiator Irg369 are added so that the solid content concentration becomes 13%. Cyclopentanone was added to the liquid crystal compositions for forming the first and second retardation layers. The name of the obtained liquid crystal composition is referred to as "composition V".
Liquid crystal compound LC242: Palocolor LC242 (registered trademark of BASF)

(Example 1)
[Manufacturing of first retardation layer]
A bar coater was applied to the alignment film composition for forming the first retardation layer on a COP film (ZF-14-50) manufactured by Nippon Zeon Corporation, dried at 80 ° C. for 1 minute, and a polarized UV irradiation device (polarized UV irradiation device). Using SPOT CURE SP-9 (manufactured by Ushio Denki Co., Ltd.), polarized UV exposure was performed at a wavelength of 313 nm, an integrated light intensity of 100 mJ / cm ² , and an axial angle of 45 °. The film thickness of the obtained first alignment film for forming a retardation layer was measured with an ellipsometer and found to be 100 nm.
Subsequently, the composition I was applied to the first retardation layer forming alignment film using a bar coater, dried at 120 ° C. for 1 minute, and then a high-pressure mercury lamp (Unicure VB-15201BY-A, Ushio Electric Co., Ltd.). The first retardation layer is formed by irradiating ultraviolet rays from the surface side coated with the composition of the retardation layer (integrated light intensity at a wavelength of 365 nm under a nitrogen atmosphere: 500 mJ / cm ² ). did. The film thickness of the obtained first alignment film for forming a retardation layer was measured with an ellipsometer and found to be 2.3 μm.

[Manufacturing of second retardation layer]
A alignment film composition for forming a second retardation layer was coated on a COP film (ZF-14-50) manufactured by Nippon Zeon Corporation with a bar coater, dried at 120 ° C. for 1 minute, and the second retardation was formed. An alignment film for layer formation was obtained. The film thickness of the obtained second alignment film for forming a retardation layer was measured with an ellipsometer and found to be 200 nm.
Subsequently, the composition I was applied to the alignment film for forming the second retardation layer using a bar coater, dried at 120 ° C. for 1 minute, and then a high-pressure mercury lamp (Unicure VB-15201BY-A, Ushio Electric Co., Ltd.). A second retardation layer is formed by irradiating ultraviolet rays from the surface side coated with the composition of the retardation layer (integrated light intensity at a wavelength of 365 nm under a nitrogen atmosphere: 500 mJ / cm ² ). did. The film thickness of the obtained second alignment film for forming a retardation layer was measured with an ellipsometer and found to be 1.2 μm.

[Re measurement of the first retardation layer and the second retardation layer]
The in-plane retardation values (Re1 (λ) and Re2 (λ)) of the first retardation layer and the second retardation layer produced by the above method have a retardation in the cycloolefin polymer film as the base material. After confirming that there was no such substance, measurements were taken with a measuring device (KOBRA-WR, manufactured by Oji Measuring Instruments Co., Ltd.) at wavelengths λ of 450 nm, 550 nm and 650 nm, respectively. The results obtained are shown in Table 2.

[Rth measurement of the first retardation layer and the second retardation layer]
The thickness direction retardation values (Rth1 (λ) and Rth2 (λ)) of the first retardation layer and the second retardation layer produced by the above method have a retardation in the cycloolefin polymer film as the base material. After confirming that there was no light, the angle of incidence of light on the sample was changed by an ellipsometer. The average refractive index at wavelengths λ at 450 nm and 550 nm was measured using a refractometer (“Multi-wavelength Abbe refractometer DR-M4” manufactured by Atago Co., Ltd.). Table 2 shows Rth1 (λ) and Rth2 (λ) at wavelengths λ at 450 nm and 550 nm calculated from the obtained film thickness, average refractive index, and measurement results of the ellipsometer.

[Calculation of Nz (λ)]
The Nz (λ) of the optical film in which the first retardation layer and the second retardation layer were laminated was calculated according to the equation (C). The calculated results are shown in Table 2.

The refractive indexes nx1 (λ), ny1 (λ) and nz1 (λ) of the obtained first retardation layer are nx1 (λ)> ny1 (λ) ≈nz1 over the entire wavelength range of λ = 400 to 700 nm. Satisfy (λ). Further, the refractive indexes nx2 (λ), ny2 (λ) and nz2 (λ) of the second retardation layer are nz2 (λ)> nx2 (λ) ≈ ny2 (λ) over the entire wavelength range of λ = 400 to 700 nm. Meet.

[Manufacturing of polarizing plate]
After immersing a polyvinyl alcohol film with an average degree of polymerization of about 2,400, a saponification degree of 99.9 mol% or more and a thickness of 75 μm in pure water at 30 ° C., the weight ratio of iodine / potassium iodide / water is 0. It was immersed in an aqueous solution of 02/2/100 at 30 ° C. for iodine staining (iodine staining step). The polyvinyl alcohol film that had undergone the iodine dyeing step was immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 12/5/100 at 56.5 ° C. to perform boric acid treatment (boric acid treatment step). ). The polyvinyl alcohol film that had undergone the boric acid treatment step was washed with pure water at 8 ° C. and then dried at 65 ° C. to obtain a substituent (thickness 27 μm after stretching) in which iodine was adsorbed and oriented on the polyvinyl alcohol. .. At this time, stretching was performed in the iodine dyeing step and the boric acid treatment step. The total draw ratio in such stretching was 5.3 times. The obtained polarizing element and a saponified triacetyl cellulose film (KC4UYTAC 40 μm manufactured by Konica Minolta) were bonded together with a nip roll via a water-based adhesive. While maintaining the tension of the obtained laminate at 430 N / m, it was dried at 60 ° C. for 2 minutes to obtain a polarizing plate having a triacetyl cellulose film as a protective film on one side. The water-based adhesive is 100 parts of water, 3 parts of carboxyl group-modified polyvinyl alcohol (Kuraray Poval KL318) and a water-soluble polyamide epoxy resin (Aqueous solution of Sumire's resin 650 solid content concentration 30% made by Sumika Chemtex). Prepared by adding 1.5 parts.

The optical characteristics of the obtained polarizing plate were measured. The measurement was carried out with a spectrophotometer (V7100, manufactured by JASCO Corporation) using the polarizing element surface of the polarizing plate obtained above as an incident surface. The obtained luminosity factor correction single transmittance was 42.1%, the luminosity factor correction polarization degree was 99.996%, the single hue a was −1.1, and the single hue b was 3.7.

[Manufacturing of elliptical polarizing plate]
First, a corona treatment was performed on the surface coated with the polymerizable liquid crystal compound of the first retardation layer, and then a pressure-sensitive adhesive (Lintec Corporation pressure-sensitive pressure-sensitive adhesive 5 μm) was applied to the polarizing plate manufactured by the above method. ), Then the substrate was peeled off to form a laminate of the polarizing plate and the first retardation layer. Subsequently, the surface coated with the polymerizable liquid crystal compound of the second retardation layer was subjected to corona treatment, and then the first phase difference from the polarizing plate via a pressure-sensitive adhesive (pressure-sensitive pressure-sensitive adhesive 5 μm manufactured by Lintec Corporation). The first retardation layer and the second retardation layer in the laminated body of the layers were bonded together. After that, the base material was peeled off to produce an elliptical polarizing plate.

[Confirmation of frontal hue and orthorhombic hue change]
The obtained elliptical polarizing plate was attached to a mirror via an adhesive, and then visually observed at a distance of 50 cm from the front to confirm the hue. In addition, the oblique hue was confirmed by visually observing at an elevation angle of 60 ° and an azimuth angle of 0 to 360 ° at a distance of 50 cm. The confirmed results are shown in Table 2.
The front hue and the orthorhombic hue are as follows.
◎: Clear black, 〇: Black, △: Red or bluish black, ×: Red or blue

(Examples 2 to 30, Comparative Examples 1 to 12)
An optical film and an elliptical polarizing plate were prepared in the same manner as in Example 1 except that the composition I was changed to the composition II, the composition III, the composition IV, or the composition V, respectively, according to the description in Table 2. The results of each measurement are shown in Table 2.
The refractive indexes nx1 (λ), ny1 (λ) and nz1 (λ) of the first retardation layer obtained in Examples 2 to 30 are nx1 (λ) over the entire wavelength λ = 400 to 700 nm. )> Ny1 (λ) ≈ nz1 (λ). Further, the refractive indexes nx2 (λ), ny2 (λ) and nz2 (λ) of the second retardation layer are nz2 (λ)> nx2 (λ) ≈ ny2 (λ) over the entire wavelength range of λ = 400 to 700 nm. Meet.

(Example 31)
The composition I is changed according to the description in Table 2, and the stacking order of the first retardation layer and the second retardation layer in the method for manufacturing an elliptical polarizing plate is changed, and the polarizing plate and the second retardation layer are first arranged. After laminating, an optical film and an elliptical polarizing plate were produced in the same manner as in Example 1 except that the order of laminating the laminated body of the polarizing plate, the second retardation layer, and the first retardation layer was changed. The measurement results are shown in Table 2.
The refractive indexes nx1 (λ), ny1 (λ) and nz1 (λ) of the first retardation layer obtained in Example 31 are nx1 (λ)> ny1 (nx1 (λ)> ny1 in the entire wavelength range of λ = 400 to 700 nm. λ) ≈nz1 (λ) is satisfied. Further, the refractive indexes nx2 (λ), ny2 (λ) and nz2 (λ) of the second retardation layer are nz2 (λ)> nx2 (λ) ≈ ny2 (λ) over the entire wavelength range of λ = 400 to 700 nm. Meet.

The elliptical polarizing plate having the first retardation layer and the second retardation layer according to the embodiment has a black front hue and an orthorhombic hue, and has excellent antireflection characteristics.

Claims (16)

An optical film having a first retardation layer and a second retardation layer and satisfying the relationships of the following equations (1) and (2).
0.4 ≤ Nz (450) ≤ 0.6 (1)
0.4 ≤ Nz (550) ≤ 0.6 (2)
[In the equation, Nz (450) indicates the Nz coefficient of the optical film for light having a wavelength λ = 450 nm, and Nz (550) indicates the Nz coefficient of the optical film for light having a wavelength λ = 550 nm. The Nz coefficient Nz (λ) of the optical film with respect to light is Nz (λ) = (nx (λ) -nz (λ)) / (nx (λ) -ny (λ)).
Indicated by. nx (λ) represents the main refractive index in the direction parallel to the film plane with respect to light having a wavelength of λ (nm) in the refractive index ellipsoid formed by the optical film. In the refractive index ellipsoid formed by the optical film, ny (λ) is a refraction in a direction parallel to the film plane with respect to light having a wavelength λ (nm) and perpendicular to the direction of the nx (λ). Represents a rate. nz (λ) represents the refractive index in the direction perpendicular to the film plane with respect to light having a wavelength of λ (nm) in the refractive index ellipsoid formed by the optical film. ] The first retardation layer is
In the refractive index ellipsoid formed by the first retardation layer, the wavelength is in the range of λ = 400 to 700 nm.
nx1 (λ)> ny1 (λ) ≒ nz1 (λ)
[In the equation, nx1 (λ) represents the main refractive index in the direction parallel to the film plane with respect to light having a wavelength of λ (nm) in the refractive index ellipsoid formed by the first retardation layer. In the refractive index ellipsoid formed by the first retardation layer, ny1 (λ) has a wavelength λ (nm) that is parallel to the film plane and orthogonal to the direction of nx1 (λ). Represents the refractive index of light. nz1 (λ) represents the refractive index in the direction perpendicular to the film plane with respect to light having a wavelength of λ (nm) in the refractive index ellipsoid formed by the first retardation layer. ]
Have a relationship with
The optical film according to claim 1, which satisfies the relationship of the following formulas (3) and (4).
Re1 (450) / Re1 (550) ≤ 1.00 (3)
1.00 ≤ Re1 (650) / Re1 (550) (4)
[In the equation, Re1 (450) is the in-plane retardation value of the first retardation layer for light having a wavelength λ = 450 nm, and Re1 (550) is the in-plane position of the first retardation layer for light having a wavelength λ = 550 nm. Re1 (650) indicates the in-plane retardation value of the first retardation layer for light having a wavelength of λ = 650 nm, and Re1 (λ) indicates the in-plane retardation value of the first retardation layer for light having a wavelength of λ nm. )teeth,
Re1 (λ) = (nx1 (λ) -ny1 (λ)) × d1
It is represented by. Here, d1 represents the thickness of the first retardation layer. ] The second retardation layer is
In the refractive index ellipsoid formed by the second retardation layer, in the wavelength range of λ = 400 to 700 nm,
nz2 (λ)> nx2 (λ) ≒ ny2 (λ)
[In the equation, nz2 (λ) represents the refractive index in the direction perpendicular to the film plane with respect to light having a wavelength of λ (nm) in the refractive index ellipsoid formed by the second retardation layer. In the refractive index ellipsoid formed by the second retardation layer, nx2 (λ) represents the maximum refractive index in the direction parallel to the film plane with respect to light having a wavelength of λ (nm). ny2 (λ) is a refractive index ellipsoid formed by the second retardation layer, with respect to light having a wavelength λ (nm) parallel to the film plane and orthogonal to the nx2 direction. Represents the refractive index. However, when nx2 (λ) = ny2 (λ), nx2 (λ) represents the refractive index in an arbitrary direction parallel to the film plane. ]
Have a relationship with
The optical film according to claim 1 or 2, which satisfies the relationship of the following formulas (5) and (6).
Rth2 (450) / Rth2 (550) ≤ 1.00 (5)
1.00 ≤ Rth2 (650) / Rth2 (550) (6)
[In the equation, Rth2 (450) is the phase difference value in the thickness direction for light having a wavelength λ = 450 nm, and Rth2 (550) is the phase difference value in the thickness direction for light having a wavelength λ = 550 nm. , Rth2 (650) represent the phase difference value in the thickness direction of the second retardation layer for light having a wavelength of 650 nm, respectively, and the phase difference value Rth2 in the thickness direction of the second retardation layer for light having a wavelength λ (nm). (Λ) is
Rth2 (λ) = [(nx2 (λ) + ny2 (λ)) / 2-nz2 (λ)] × d2
It is represented by. Here, in the refractive index ellipse formed by the second retardation layer, nz2 (λ) represents the main refractive index in the direction perpendicular to the film plane at the wavelength λ (nm), and ((nx2 (λ) + ny2). (Λ)) / 2) represents the average refractive index in the film plane at the wavelength λ (nm). d2 represents the thickness of the second retardation layer. ] The optical film according to any one of claims 1 to 3, wherein the first retardation layer further satisfies the relationship of the following formula (7).
120nm ≤ Re1 (550) ≤ 170nm (7)
[In the equation, Re1 (550) represents the in-plane retardation value of the first retardation layer with respect to light having a wavelength λ = 550 nm. ] The optical film according to any one of claims 1 to 4, wherein the second retardation layer further has optical characteristics represented by the formula (9).
-100nm ≤ Rth2 (550) ≤ -50nm (8)
[In the equation, Rth2 (550) represents the phase difference value in the thickness direction of the second phase difference layer with respect to light having a wavelength λ = 550 nm. ] The optical film according to any one of claims 1 to 5, wherein the second retardation layer is a film formed by polymerizing a polymerizable liquid crystal in an oriented state. The optical film according to any one of claims 1 to 6, wherein the first retardation layer is a film formed by polymerizing a polymerizable liquid crystal in an oriented state. The optical film according to any one of claims 1 to 7, wherein the second retardation layer is 5 μm or less. The optical film according to any one of claims 1 to 8, wherein the first retardation layer is 5 μm or less. The optical film according to any one of claims 1 to 9, wherein the first retardation layer and the second retardation layer are coating layers formed by mainly polymerizing the same polymerizable liquid crystal compound. An elliptical polarizing plate with an optical compensation function having the optical film according to any one of claims 1 to 10 and a polarizing plate. The absorption axis of the polarizing plate and the slow axis of the first retardation layer have a relationship of 45 ± 5 ° or 135 ± 5 ° in the film plane, and the absorption axis of the polarizing plate and the first retardation layer The elliptical polarizing plate with an optical compensation function according to claim 11, wherein the slow axis of the above and the slow axis of the second retardation layer are orthogonal to the film surface in the vertical direction. The ellipse with an optical compensation function according to claim 11 or 12, which is an optical laminate in which a polarizing plate, an adhesive layer, a first retardation layer, an adhesive layer, and a second retardation layer are formed in this order. Polarizer. The ellipse with an optical compensation function according to claim 11 or 12, which is an optical laminate in which a polarizing plate, an adhesive layer, a second retardation layer, an adhesive layer, and a first retardation layer are formed in this order. Polarizer. An organic EL display device comprising the elliptical polarizing plate with an optical compensation function according to any one of claims 12 to 14. The method for manufacturing an elliptical polarizing plate with an optical compensation function according to any one of claims 11 to 14, which includes all of the following steps.
(Step 1-A) A step of applying a polymerizable liquid crystal compound on a substrate on which a horizontally oriented film is formed and then polymerizing the compound in a horizontally oriented state to form a retardation layer.
(Step 1-B) A step of applying a polymerizable liquid crystal compound on a substrate on which a vertically oriented film is formed and then polymerizing the polymer in a vertically oriented state to form a second retardation layer.
(Step 2) A step of transferring the liquid crystal polymer of the first retardation layer and the liquid crystal polymer of the second retardation layer from a substrate via an adhesive and laminating them on a polarizing plate.