WO2019003812A1

WO2019003812A1 - Optically anisotropic layer and method for producing same, optically anisotropic laminate, multi-layered article for transfer use, polarizing plate, and image display device

Info

Publication number: WO2019003812A1
Application number: PCT/JP2018/021402
Authority: WO
Inventors: 航中野
Original assignee: 日本ゼオン株式会社
Priority date: 2017-06-30
Filing date: 2018-06-04
Publication date: 2019-01-03
Also published as: TWI767015B; JP7276128B2; KR102589809B1; TW201905119A; CN110651208A; CN110651208B; JPWO2019003812A1; KR20200019143A

Abstract

An optically anisotropic layer containing a positive C-type polymer and a polymerization product of a mesogenic compound, wherein the mesogenic compound is a compound having a mesogenic backbone and an acrylate structure, and the optically anisotropic layer satisfies the requirement represented by the formula: 0.073 < AC-H/AC=O (mesogenic compound) < 0.125. AC-H represents an infrared absorption associated with the out-of-plane bending vibration of a C-H bond in the acrylate structure in infrared absorption spectra of the optically anisotropic layer; and AC=O (mesogenic compound) represents the sum total of an infrared absorption associated with the stretching vibration of a C=O bond in the acrylate structure and an infrared absorption associated with the stretching vibration of a C=O bond derived from the C=O bond in the acrylate structure in infrared absorption spectra of the optically anisotropic layer. The production of an optically anisotropic layer, and a use of the optically anisotropic layer.

Description

Optically anisotropic layer and method for producing the same, optically anisotropic laminate, multilayer for transfer, polarizing plate, and image display device

The present invention relates to an optically anisotropic layer and a method for producing the same; an optically anisotropic laminate comprising the above-mentioned optically anisotropic layer; a transfer multilayer comprising the above-mentioned optically anisotropic layer; The present invention relates to a board and an image display device.

Various optical films are provided in image display devices, such as a liquid crystal display device and an organic electroluminescent display device. Hereinafter, "organic electroluminescence" may be referred to as "organic EL" as appropriate. The technology related to such an optical film has been studied conventionally (for example, Patent Documents 1 and 2).

JP, 2015-14712, A JP, 2015-57646, A (correspondence gazette: U.S. patent application publication 2015/041051 specification)

A circularly polarizing plate may be provided on the display surface of the image display device. As said circularly-polarizing plate, the optical film provided with a linear polarizer and an optically anisotropic layer is used normally. By providing a circularly polarizing plate on the display surface of the image display device, reflection of external light can be suppressed or light for displaying an image can be transmitted through polarized sunglasses when the display surface is viewed from the front direction. Therefore, it is possible to enhance the visibility of the image.

The effect of the circularly polarizing plate described above may be lost when the display surface is viewed from the tilt direction. In order to enhance the effect when the display surface is viewed from the inclined direction, it is conceivable to provide a positive C film in combination with a circularly polarizing plate. It is preferable that the positive C film used for such an application is a film in which the retardation Rth in the thickness direction exhibits reverse wavelength dispersion. Such a positive C film can be considered to be produced by a production method using a liquid crystal compound, as described in Patent Documents 1 and 2, for example.

However, in the prior art, it was not easy to manufacture a positive C film in which the retardation Rth in the thickness direction exhibits reverse wavelength dispersion. For example, in the method using the alignment film as in the manufacturing method using the liquid crystal compound described in Patent Documents 1 and 2, it is required to adjust the compatibility between the alignment film and the liquid crystal compound, so the adjustment is complicated. is there. Furthermore, the use of the alignment film may increase the cost because the number of steps for coating the alignment film on the substrate is increased. In addition, various characteristics other than wavelength dispersion are required for the optical film used in the image display device. For example, optical films are required to have high durability and good color tone. Positive C films with reverse wavelength dispersive Rth in the prior art may be inferior in such durability and color tone. For example, while optical films are generally required to have less degradation due to long-term use in a high temperature environment, the positive C film having reverse wavelength dispersive Rth in the prior art is required to be used for a long time in a high temperature environment. As a result of use, it is easy to cause problems such as increase in haze and clouding. In general, an optical film is required to be close to colorless with no deviation of transmittance and reflectance depending on the wavelength of light, and a positive C film having reverse wavelength dispersion Rth in the prior art also has its color tone It is not colorless and may have a color tone such as yellow.

Therefore, an object of the present invention is to provide an optically anisotropic layer having high durability and good color tone in a positive C plate which can be manufactured without using an alignment film and the retardation Rth in the thickness direction exhibits reverse wavelength dispersion. And a transfer double layer provided with the optically anisotropic layer, a method for producing the same, an optically anisotropic laminate having such an optically anisotropic layer, a transfer double layer, a polarizing plate, and an image display device Intended to provide.

The present invention is as follows.
[1] An optically anisotropic layer comprising a positive C polymer, a mesogen compound, and a polymer of the mesogen compound,
When the film of the positive C polymer is formed by a coating method using a solution of the positive C polymer, the positive C polymer is a polymer in which the film satisfies the formula (1),
The mesogen compound is a compound having a mesogen skeleton and an acrylate structure,
The optically anisotropic layer is an optically anisotropic layer that satisfies Formula (2) and Formula (3):
nz (P)> nx (P) ≧ ny (P) Formula (1)
nz (A)> nx (A) ≧ ny (A) Formula (2)
0.073 <A _C−H / A _{C = O} (mesogenic compound) <0.125 Formula (3)
However,
nx (P), ny (P) and nz (P) are the main refractive indices of the film,
nx (A), ny (A) and nz (A) are main refractive indices of the optically anisotropic layer,
_AC-H is infrared absorption concerning out-of-plane bending vibration of C—H bond of the acrylate structure of the mesogen compound in infrared absorption spectrum of the optically anisotropic layer,
A _{C = O} (mesogen compound) is an infrared absorption of the stretching vibration of the C = O bond of the acrylate structure of the mesogen compound in the infrared absorption spectrum of the optically anisotropic layer, and the absorption of the mesogen compound It is the sum of infrared absorption applied to the stretching vibration of the C = O bond derived from the C = O bond of the acrylate structure.
[2] The optically anisotropic layer according to [1], which is a compound which exhibits reverse wavelength dispersive in-plane retardation when the mesogen compound is homogeneously aligned.
[3] The optically anisotropic layer according to [1] or [2], which satisfies the formulas (4) and (5):
0.50 <Rth (A450) / Rth (A550) <1.00 Formula (4)
1.00 ≦ Rth (A650) / Rth (A550) <1.25 Formula (5)
However,
Rth (A450) is a retardation in the thickness direction of the optically anisotropic layer at a wavelength of 450 nm,
Rth (A550) is a retardation in the thickness direction of the optically anisotropic layer at a wavelength of 550 nm,
Rth (A650) is a retardation in the thickness direction at a wavelength of 650 nm of the optically anisotropic layer.
[4] The optically anisotropic layer according to any one of [1] to [3], wherein the mesogen compound is represented by the following formula (I):

(In the above formula (I),
Y ¹ to Y ⁸ each independently represent a single chemical bond, —O—, —S—, —O—C (= O) —, —C (= O) —O—, —O—C (= O) -O-, -NR ¹ -C (= O)-, -C (= O) -NR ^1- , -O-C (= O) -NR ^1- , -NR ¹ -C (= O) -O-, -NR ¹ -C (= O) -NR ^1- , -O-NR ^1- , or -NR ¹ -O-. Here, R ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
G ¹ and G ² each independently represent an optionally substituted divalent aliphatic group having 1 to 20 carbon atoms. In addition, in the aliphatic group, one or more -O-, -S-, -O-C (= O)-, -C (= O) -O-, -O-C per aliphatic group. ^{(= O) -O -, -} NR 2 -C (= O) -, - C (= O) -NR 2 -, - NR 2 -, or, -C (= O) - is be interposed Good. However, it excludes the case where two or more -O- or -S- are adjacent to each other. Here, R ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Z ¹ and Z ² each independently represent an alkenyl group having 2 to 10 carbon atoms which may be substituted by a halogen atom.
A ^x represents an organic group having 2 to 30 carbon atoms which has at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring.
A ^y has a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, and a substituent Also a cycloalkyl group having 3 to 12 carbon atoms, an alkynyl group having 2 to 20 carbon atoms which may have a substituent, -C (= O) -R ³ , -SO ₂ -R ⁴ , -C ( = S) NH-R ⁹ , or an organic group having 2 to 30 carbon atoms, having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocycle. Here, R ³ has an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, and a substituent. Or a cycloalkyl group having 3 to 12 carbon atoms or an aromatic hydrocarbon ring group having 5 to 12 carbon atoms. R ⁴ represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a phenyl group or a 4-methylphenyl group. R ⁹ is an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, carbon which may have a substituent And a cycloalkyl group of 3 to 12 or an aromatic group of 5 to 20 carbon atoms which may have a substituent. The aromatic ring which said A ^x and A ^y has may have a substituent. The A ^x and A ^y may be taken together to form a ring.
A ¹ represents a trivalent aromatic group which may have a substituent.
Each of A ² and A ³ independently represents a divalent alicyclic hydrocarbon group having 3 to 30 carbon atoms which may have a substituent.
Each of A ⁴ and A ⁵ independently represents a divalent aromatic group having 6 to 30 carbon atoms which may have a substituent.
Q ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent.
m and n each independently represent 0 or 1;
However, one or both of Z ¹ -Y ⁷ -and -Y ⁸ -Z ² are acryloyloxy groups. )
[5] Any one of [1] to [4], wherein the mesogen compound contains, in its molecular structure, at least one selected from the group consisting of a benzothiazole ring and a combination of a cyclohexyl ring and a phenyl ring The optically anisotropic layer as described in 1 or 2.
[6] The optical according to any one of [1] to [5], wherein the positive C polymer is at least one polymer selected from the group consisting of polyvinyl carbazole, polyfumarate and a cellulose derivative. Anisotropic layer.
[7] The composition according to any one of [1] to [6], wherein the proportion of the mesogen compound and the polymer thereof in the total solid content of the optically anisotropic layer is 20% by weight or more and 60% by weight or less. Optically anisotropic layer.
[8] The optically anisotropic layer according to any one of [1] to [7], which satisfies the formulas (6) and (7):
Re (A 590) ≦ 10 nm Formula (6)
−200 nm ≦ Rth (A 590) ≦ -10 nm Formula (7)
However,
Re (A 590) is an in-plane retardation of the optically anisotropic layer at a wavelength of 590 nm,
Rth (A 590) is a retardation in the thickness direction at a wavelength of 590 nm of the optically anisotropic layer.
[9] A transfer multi-layer material comprising a substrate and the optically anisotropic layer according to any one of [1] to [8].
[10] An optical anisotropic layer according to any one of [1] to [8] and a retardation layer,
The optically anisotropic laminate, wherein the retardation layer satisfies formula (8):
nx (B)> ny (B) ≧ nz (B) Formula (8)
However, nx (B), ny (B) and nz (B) are the main refractive indexes of the said phase difference layer.
[11] The optically anisotropic laminate according to [10], wherein the retardation layer satisfies Formulas (9) and (10):
0.75 <Re (B450) / Re (B550) <1.00 Formula (9)
1.01 <Re (B650) / Re (B550) <1.25 Formula (10)
However,
Re (B450) is an in-plane retardation of the retardation layer at a wavelength of 450 nm,
Re (B550) is an in-plane retardation of the retardation layer at a wavelength of 550 nm,
Re (B650) is an in-plane retardation of the retardation layer at a wavelength of 650 nm.
[12] The optically anisotropic laminate according to [11], wherein the retardation layer contains a liquid crystal compound for retardation layer represented by the following formula (II):

(In the above formula (II),
Y ¹ to Y ⁸ each independently represent a single chemical bond, —O—, —S—, —O—C (= O) —, —C (= O) —O—, —O—C (= O) -O-, -NR ¹ -C (= O)-, -C (= O) -NR ^1- , -O-C (= O) -NR ^1- , -NR ¹ -C (= O) -O-, -NR ¹ -C (= O) -NR ^1- , -O-NR ^1- , or -NR ¹ -O-. Here, R ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
G ¹ and G ² each independently represent an optionally substituted divalent aliphatic group having 1 to 20 carbon atoms. In addition, in the aliphatic group, one or more -O-, -S-, -O-C (= O)-, -C (= O) -O-, -O-C per aliphatic group. ^{(= O) -O -, -} NR 2 -C (= O) -, - C (= O) -NR 2 -, - NR 2 -, or, -C (= O) - is be interposed Good. However, it excludes the case where two or more -O- or -S- are adjacent to each other. Here, R ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Z ¹ and Z ² each independently represent an alkenyl group having 2 to 10 carbon atoms which may be substituted by a halogen atom.
A ^x represents an organic group having 2 to 30 carbon atoms which has at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring.
A ^y has a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, and a substituent Also a cycloalkyl group having 3 to 12 carbon atoms, an alkynyl group having 2 to 20 carbon atoms which may have a substituent, -C (= O) -R ³ , -SO ₂ -R ⁴ , -C ( = S) NH-R ⁹ , or an organic group having 2 to 30 carbon atoms, having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocycle. Here, R ³ has an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, and a substituent. Or a cycloalkyl group having 3 to 12 carbon atoms or an aromatic hydrocarbon ring group having 5 to 12 carbon atoms. R ⁴ represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a phenyl group or a 4-methylphenyl group. R ⁹ is an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, carbon which may have a substituent And a cycloalkyl group of 3 to 12 or an aromatic group of 5 to 20 carbon atoms which may have a substituent. The aromatic ring which said A ^x and A ^y has may have a substituent. The A ^x and A ^y may be taken together to form a ring.
A ¹ represents a trivalent aromatic group which may have a substituent.
Each of A ² and A ³ independently represents a divalent alicyclic hydrocarbon group having 3 to 30 carbon atoms which may have a substituent.
Each of A ⁴ and A ⁵ independently represents a divalent aromatic group having 6 to 30 carbon atoms which may have a substituent.
Q ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent.
m and n each independently represent 0 or 1; )
[13] Linear polarizer,
The optically anisotropic layer according to any one of [1] to [8], the multilayer for transfer according to [9], or the optical according to any one of [10] to [12] An anisotropic laminate, and a polarizing plate.
[14] An image display device comprising the polarizing plate according to [13].
[15] The optically anisotropic laminate according to any one of [10] to [12],
With linear polarizers,
An image display device, in this order,
The image display apparatus whose said image display element is a liquid crystal cell or an organic electroluminescent element.
[16] A method for producing an optically anisotropic layer according to any one of [1] to [8], which
Providing a coating liquid containing a positive C polymer, a mesogen compound, a solvent, a photopolymerization initiator, and a crosslinking agent;
Applying the coating solution on a support surface to obtain a coating solution layer;
And irradiating the coating liquid layer with light to cure the coating liquid layer.
[17] The ratio of the photopolymerization initiator to 100 parts by weight of the mesogen compound in the coating liquid is 1 part by weight to 10 parts by weight,
The method for producing an optically anisotropic layer according to [16], wherein the ratio of the crosslinking agent to 100 parts by weight of the mesogen compound is 1 part by weight to 10 parts by weight.
[18] integrated light amount of the light to be irradiated is ^{600mJ / cm 2 ~ 5000mJ / cm} 2, the production method according to [16] or [17].

According to the present invention, an optically anisotropic layer having high durability and good color tone, which can be manufactured without using an alignment film and having a positive C-plate exhibiting a reverse wavelength dispersion with retardation Rth in the thickness direction A transfer multilayer having the optically anisotropic layer, a method for producing the same, an optically anisotropic laminate having such an optical anisotropic layer, a transfer multilayer, a polarizing plate, and an image display device Provided.

Hereinafter, the present invention will be described in detail by way of embodiments and exemplifications. However, the present invention is not limited to the embodiments and examples shown below, and can be implemented with arbitrary modifications without departing from the scope of the claims of the present invention and the equivalents thereof.

In the following description, the front direction of a surface means, unless otherwise specified, the normal direction of the surface, specifically, the direction of the polar angle of 0 ° and the azimuth angle of 0 ° of the surface.

In the following description, the inclination direction of a surface means a direction neither parallel nor perpendicular to the surface unless specifically stated otherwise, specifically, the polar angle of the surface is larger than 0 ° and smaller than 90 ° Point in the direction of

In the following description, unless otherwise specified, the in-plane retardation Re of a certain layer represents a value represented by Re = (nx−ny) × d, and the retardation Rth in the thickness direction of a certain layer , Rth = [{(nx + ny) / 2} −nz] × d. Here, nx represents the in-plane direction of the layer and represents the refractive index in the direction giving the maximum refractive index, and ny represents the refractive index in the in-plane direction of the layer and orthogonal to the nx direction. And nz represents the refractive index in the thickness direction of the layer, and d represents the thickness of the layer. Further, the in-plane direction indicates a direction perpendicular to the thickness direction.

In the following description, unless otherwise stated, the measurement wavelength of the refractive index is 590 nm.

In the following description, the term "long" member refers to a member having a length of 5 times or more the width, preferably 10 times or more, and more specifically, A member having a length that can be rolled up and stored or transported. The upper limit of the length of the long member is not particularly limited, and may be, for example, 100,000 times or less of the width.

In the following description, the “polarizing plate” and the “wave plate” include not only a rigid member but also a flexible member such as a resin film.

In the following description, unless otherwise specified, "(meth) acrylic" is a term including "acrylic", "methacrylic" and combinations thereof.

In the following description, unless the directions of the elements “parallel” and “vertical” are different, they may include an error within a range that does not impair the effect of the present invention, for example, within ± 5 °. .

In the following description, a resin having a positive intrinsic birefringence value means a resin in which the refractive index in the stretching direction is larger than the refractive index in the direction orthogonal thereto. Further, a resin having a negative intrinsic birefringence value means a resin in which the refractive index in the stretching direction is smaller than the refractive index in the direction orthogonal thereto. The intrinsic birefringence value can be calculated from the dielectric constant distribution.

In the following description, the main refractive index of a layer or film means the refractive index nx of the layer in the in-plane direction of the layer giving the maximum refractive index, and the in-plane direction of the layer provides the nx The refractive index ny in the direction perpendicular to the direction, and the refractive index nz in the thickness direction of the layer. In the present application, the refractive indices corresponding to these nx, ny and nz are represented by symbols including the character strings “nx”, “ny” and “nz”, respectively. For example, among the main refractive indices nx (A), ny (A) and nz (A) of the optically anisotropic layer, nx (A) is the in-plane direction of the optically anisotropic layer and the maximum refractive index Ny (A) is the in-plane direction of the optically anisotropic layer and is perpendicular to the direction giving nx (A), nz (A) is It is a refractive index of the thickness direction of an optically anisotropic layer.

In the following description, “in-plane retardation Re of a layer exhibits reverse wavelength dispersion” means that in-plane retardations Re (450) and Re (550) at wavelengths 450 nm and 550 nm of the layer are Re (450). ) / Re (550) <1.00 is satisfied. In the layer in which Re has reverse wavelength dispersion, preferably, in-plane retardations Re (550) and Re (650) at wavelengths 550 nm and 650 nm of the layer are Re (550) / Re (650) <1. Meet 00
The retardation Rth in the thickness direction of a certain layer shows reverse wavelength dispersion, as the retardation Rth (450) and Rth (550) in the thickness direction at wavelengths 450 nm and 550 nm of the layer is Rth (450) / Rth. (550) means to satisfy <1.00. In the layer in which Rth has reverse wavelength dispersion, preferably, retardations Rth (550) and Rth (650) in the thickness direction at wavelengths 550 nm and 650 nm of the layer are Rth (550) / Rth (650) <1. Meet .00.

[1. Optical anisotropic layer]
The optically anisotropic layer of the present invention contains a positive C polymer, a mesogen compound, and a polymer of the mesogen compound, and has specific optical properties.

[1.1. Positive C polymer]
The positive C polymer is a polymer, and when the film of the polymer is formed by a coating method using a solution of the polymer, the film satisfies the formula (1).
nz (P)> nx (P) ≧ ny (P) Formula (1)
Where nx (P), ny (P) and nz (P) are the main refractive indices of such films. An optical anisotropy which can be manufactured without using an alignment film by using such a positive C polymer in combination with a mesogen compound, and which is used as a positive C film in which the retardation Rth in the thickness direction exhibits reverse wavelength dispersion. Sex layer can be realized.

Whether a certain polymer corresponds to a positive C polymer can be confirmed by the following method.
First, a polymer as a sample is added to a solvent such as methyl ethyl ketone (MEK), 1,3-dioxolane, N-methyl pyrrolidone (NMP) or the like so that the concentration of the polymer is 10 wt% to 20 wt%, Dissolve at room temperature to obtain a polymer solution.
This polymer solution is coated on an unstretched film made of resin using an applicator to form a layer of the polymer solution. Thereafter, the film is dried in an oven at 85 ° C. for about 10 minutes, and the solvent is evaporated to obtain a polymer film having a thickness of about 10 μm.
Then, it is evaluated whether or not the refractive index nx (P), the refractive index ny (P) and the refractive index nz (P) of this polymer film satisfy the formula (1), and in the case where the formula is satisfied: The polymer can be determined to correspond to a positive C polymer.

Among them, it is preferable that the refractive index nx (P) and the refractive index ny (P) have the same value or be close to each other. Specifically, the difference nx (P) -ny (P) between the refractive index nx (P) and the refractive index ny (P) is preferably 0.00000 to 0.00100, more preferably 0.00000 to 0. It is 00050, particularly preferably 0.00000 to 0.00020. When the refractive index difference nx (P) -ny (P) falls within the above range, the optically anisotropic layer of the present invention can be easily obtained.

As a positive C polymer, when a film of a positive C polymer is formed by a coating method using a solution of the positive C polymer, any film having a refractive index satisfying the above formula (1) can be obtained. Coalescing can be used. Among them, as the positive C polymer, at least one polymer selected from the group consisting of polyvinyl carbazole, polyfumaric acid ester and cellulose derivative is preferable. By using these polymers as positive C polymers, it is possible to easily obtain an optically anisotropic layer having a large retardation Rth in the thickness direction by coating.

Examples of polyvinylcarbazole include polymers containing polymerized units formed by polymerization of 9-vinylcarbazole.
Examples of polyfumarates include copolymers of diisopropyl fumarate and 3-ethyl-3-oxetanylmethyl acrylate; and copolymers of diisopropyl fumarate and cinnamate.

The positive C polymer may be used alone or in combination of two or more at an arbitrary ratio.

The proportion of the positive C polymer in the total solid content of the optically anisotropic layer is preferably 30% by weight or more, more preferably 35% by weight or more, and most preferably 40% by weight or more, preferably 60% by weight or less. More preferably, it is at most 55 wt%, most preferably at most 50 wt%. When the ratio of the positive C polymer is at least the lower limit value of the above range, the mesogenic compound can be dispersed uniformly in the optically anisotropic layer, or the mechanical strength of the optically anisotropic layer can be increased. Moreover, by being below the upper limit value of the said range, wavelength dispersion of the retardation Rth of the thickness direction of an optically anisotropic layer can be made easy to approach reverse dispersion. Here, the solid content of a certain layer refers to a component remaining when the layer is dried.

[1.2. Mesogenic compound]
In the present application, the mesogen compound is a compound having a mesogen skeleton and an acrylate structure.
The mesogenic skeleton possessed by the mesogenic compound means a molecular skeleton which essentially contributes to the generation of a liquid crystal phase in a substance of low molecular weight or high molecular weight by the anisotropy of its attractive force and repulsive interaction. The mesogen compound containing a mesogen skeleton may not necessarily have liquid crystallinity that can cause phase transition to a liquid crystal phase by itself. Therefore, the mesogen compound may be a liquid crystal compound capable of causing a phase transition to a liquid crystal phase alone, or may be a non-liquid crystal compound not causing a phase transition to a liquid crystal phase alone. Examples of mesogenic frameworks include rigid rod-like or disk-like shaped units. For the mesogen skeleton, see Pure Appl. Chem. 2001, 73 (5), 888 and C.I. Tschierske, G., et al. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368.

In the optically anisotropic layer, the orientation state of the mesogen compound may be fixed. For example, in the mesogen compound, the orientation state of the mesogen compound may be fixed by polymerization. In general, since the mesogen compound can be a polymer while maintaining the orientation state of the mesogen compound by polymerization, the orientation state of the mesogen compound is fixed by the above-mentioned polymerization. Thus, the term "mesogenic compound with fixed orientation" includes polymers of mesogenic compounds. Therefore, when the mesogen compound is a liquid crystal compound having liquid crystallinity, this liquid crystal compound may exhibit a liquid crystal phase in the optically anisotropic layer, and exhibits a liquid crystal phase by fixing the alignment state. It does not have to be.

As the mesogen compound, a reverse wavelength dispersion liquid crystal compound, a reverse wavelength mesogen compound, or a combination thereof can be used.

Here, the reverse wavelength dispersion liquid crystal compound means a compound which satisfies all the following requirements (i) and (ii).
(I) The reverse wavelength dispersion liquid crystal compound exhibits liquid crystallinity.
(Ii) The reverse wavelength dispersion liquid crystal compound exhibits an in-plane retardation of reverse wavelength dispersion when it is homogeneously aligned.

In addition, the reverse wavelength mesogen compound means a compound that satisfies all of the following requirements (iii), (iv) and (v).
(Iii) The reverse wavelength mesogen compound does not exhibit liquid crystallinity by itself.
(Iv) The specific evaluation mixture containing the reverse wavelength mesogen compound exhibits liquid crystallinity.
(V) When the evaluation mixture is homogeneously oriented, the reverse wavelength mesogen compound exhibits in-plane retardation of reverse wavelength dispersion.
The above evaluation mixture is a liquid crystal compound for evaluation which exhibits an in-plane retardation of normal wavelength dispersion when homogeneously aligned, the above-mentioned reverse wavelength mesogen compound, a total of 100 for the liquid crystal compound for evaluation and the reverse wavelength mesogen compound. The mixture is a mixture of at least 30 parts by weight and 70 parts by weight with respect to the parts by weight.

Optical anisotropy which can be manufactured without using an alignment film by using such a mesogen compound in combination with a positive C polymer, and which is used as a positive C film in which the retardation Rth in the thickness direction exhibits reverse wavelength dispersion Sex layer can be realized.

The reverse wavelength dispersive liquid crystal compound will be described below.
The reverse wavelength dispersion liquid crystal compound exhibits an in-plane retardation of reverse wavelength dispersion when it is homogeneously aligned. Here, to homogeneously align the liquid crystal compound means to form a layer containing the liquid crystal compound, and the major axis direction of the mesogen skeleton of the molecules of the liquid crystal compound in that layer is one direction parallel to the plane of the layer It is meant to be oriented to In the case where the liquid crystal compound contains plural types of mesogen skeletons having different alignment directions, the direction in which the longest type of mesogen is aligned is the alignment direction. Whether or not the liquid crystal compound is homogeneously aligned, and the alignment direction, the measurement of the slow axis direction using a retardation meter represented by AxoScan (manufactured by Axometrics), and the incident angle in the slow axis direction It can confirm by measurement of each retardation distribution.

When a liquid crystal layer containing a reverse wavelength dispersive liquid crystal compound is formed, and the long axis direction of the mesogen skeleton of the molecules of the liquid crystal compound in the liquid crystal layer is oriented in one direction parallel to the surface of the liquid crystal layer The in-plane retardations Re (L450) and Re (L550) at wavelengths 450 nm and 550 nm of the liquid crystal layer generally satisfy Re (L450) / Re (L550) <1.00.

Furthermore, the in-plane retardations Re (L450), Re (L550) and Re (L650) of the liquid crystal layer at wavelengths of 450 nm, 550 nm and 650 nm are more preferable from the viewpoint of better exhibiting the desired effect of the present invention. It is more preferable to satisfy (L450) <Re (L550) ≦ Re (L650).

As the reverse wavelength dispersive liquid crystal compound, for example, a compound containing a main chain mesogen skeleton and a side chain mesogen skeleton bonded to the main chain mesogen skeleton in the molecule of the reverse wavelength dispersive liquid crystal compound can be used. In the reverse wavelength dispersive liquid crystal compound containing a main chain mesogen skeleton and a side chain mesogen skeleton, the side chain mesogen skeleton may be oriented in a direction different from that of the main chain mesogen skeleton in a state where the reverse wavelength dispersive liquid crystal compound is aligned. In such a case, birefringence is expressed as the difference between the refractive index corresponding to the main chain mesogen skeleton and the refractive index corresponding to the side chain mesogen skeleton, and as a result, the reverse wavelength dispersive liquid crystal compound is homogeneously aligned. And in-plane retardation of reverse wavelength dispersion.

For example, like the compounds having a main chain mesogen skeleton and a side chain mesogen skeleton, the reverse wavelength dispersive liquid crystal compound usually has a specific steric shape different from the steric shape of a general forward wavelength dispersive liquid crystal compound. Here, the “forward wavelength dispersive liquid crystal compound” refers to a liquid crystal compound capable of exhibiting in-plane retardation of forward wavelength dispersion when it is homogeneously aligned. Further, the in-plane retardation of the forward wavelength dispersion refers to the in-plane retardation in which the in-plane retardation decreases as the measurement wavelength increases. It is surmised that the fact that the reverse wavelength dispersion liquid crystal compound has such a specific three-dimensional shape is one factor for obtaining the effects of the present invention.

The CN point of the reverse wavelength dispersion liquid crystal compound is preferably 25 ° C. or more, more preferably 45 ° C. or more, particularly preferably 60 ° C. or more, preferably 120 ° C. or less, more preferably 110 ° C. or less, particularly preferably 100 ° C. It is below. Here, the “CN point” refers to the crystal-nematic phase transition temperature. An optically anisotropic layer can be easily produced by using a reverse wavelength dispersive liquid crystal compound having a CN point in the above range.

The molecular weight of the reverse wavelength dispersive liquid crystal compound is preferably 300 or more, more preferably 700 or more, particularly preferably 1000 or more, and preferably 2000 or less, more preferably 1700 or less, particularly preferably a monomer when it is a monomer. It is 1500 or less. When the reverse wavelength dispersion liquid crystal compound has a molecular weight as described above, the coatability of the coating liquid for forming the optically anisotropic layer can be made particularly favorable.

The above-mentioned reverse wavelength dispersive liquid crystal compounds may be used alone or in combination of two or more at an arbitrary ratio.

Examples of the reverse wavelength dispersive liquid crystal compound include those described in JP-A-2014-123134. Moreover, as a reverse wavelength dispersion liquid crystal compound, the compound which shows liquid crystallinity is mentioned among the compounds represented by following formula (Ia), for example. In the following description, the compound represented by the formula (Ia) may be referred to as “compound (Ia)” as appropriate.

In the above formula (Ia), A ^1a is an aromatic carbon having, as a substituent, an organic group having 1 to 67 carbon atoms having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring A hydrogen ring group; or an aromatic heterocyclic group having, as a substituent, an organic group having 1 to 67 carbon atoms having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring; .

As a specific example of A ^1a , a table is represented by the formula: -R ^f C (= N-N (R ^g ) R ^h ) or the formula:-R ^f C (= N-N = C (R ^g1 ) R ^h ) Substituted phenylene group; benzothiazol-4,7-diyl group substituted by 1-benzofuran-2-yl group; substituted by 5- (2-butyl) -1-benzofuran-2-yl group Benzothiazole-4,7-diyl; benzothiazole-4,7-diyl substituted by 4,6-dimethyl-1-benzofuran-2-yl; 6-methyl-1-benzofuran-2- Substituted benzothiazole-4,7-diyl; 4,6,7-trimethyl-1-benzofuran-2-yl substituted benzothiazole-4,7-diyl; 4,5, 6-trimethyl-1-benzofuran-2-yl group Substituted benzothiazole-4,7-diyl group; benzothiazole-4,7-diyl group substituted by 5-methyl-1-benzofuran-2-yl group; 5-propyl-1-benzofuran-2-yl group -Substituted benzothiazol-4,7-diyl; 7-propyl-1-benzofuran-2-yl substituted benzothiazol-4,7-diyl; 5-fluoro-1-benzofuran-2 -Yl substituted benzothiazole-4,7-diyl; phenyl substituted benzothiazole-4,7-diyl; 4-fluorophenyl substituted benzothiazole-4,7-diyl A benzothiazole-4,7-diyl group substituted by 4-nitrophenyl group; a benzothiazole-4 substituted by 4-trifluoromethylphenyl group, -Diyl group; benzothiazole-4,7-diyl group substituted by 4-cyanophenyl group; benzothiazole-4,7-diyl group substituted by 4-methanesulfonylphenyl group; thiophen-2-yl group Substituted benzothiazole-4,7-diyl group; benzothiazole-4,7-diyl group substituted by thiophen-3-yl group; benzothiazole-4 substituted by 5-methylthiophen-2-yl group 5, 7-diyl; benzothiazole-4, 7-diyl substituted by 5-chlorothiophen-2-yl; benzothiazole substituted by thieno [3, 2-b] thiophen-2-yl 4,7-diyl group; benzothiazole-4,7-diyl group substituted by 2-benzothiazolyl group; benzothiazole substituted by 4-biphenyl group 4-, 7-diyl group; benzothiazole-4, 7-diyl group substituted with 4-propylbiphenyl group; benzothiazole-4, 7-diyl group substituted with 4-thiazolyl group; 1-phenylethylene-2- -Substituted benzothiazole-4,7-diyl; 4-pyridyl-substituted benzothiazole-4,7-diyl; 2-furyl-substituted benzothiazole-4,7-diyl A benzothiazole-4,7-diyl group substituted with a naphtho [1,2-b] furan-2-yl group; 1H-isoindole-1,3 substituted with a 5-methoxy-2-benzothiazolyl group; (2H) -dione-4,7-diyl group; 1H-isoindole-1,3 (2H) -dione-4,7-diyl group substituted by phenyl group; substituted by 4-nitrophenyl group 1H-isoindole-1,3 (2H) -dione-4,7-diyl group; or 1H-isoindole-1,3 (2H) -dione-4,7 substituted with 2-thiazolyl group -Diyl group; and the like. Here, R ^f has the same meaning as Q ¹ described later. R ^g and R ^g1 each independently represent the same meaning as A ^y described later, and R ^h represents the same meaning as A ^x described later.

In Formula (Ia), each of Y ^1a to Y ^8a independently represents a chemical single bond, —O—, —S—, —O—C (= O) —, —C (= O) — O-, -O-C (= O) -O-, -NR ¹ -C (= O)-, -C (= O) -NR ^1- , -O-C (= O) -NR ^1- , -NR ¹ -C (= O) -O-, -NR ¹ -C (= O) -NR ^1- , -O-NR ^1- , or -NR ¹ -O-. Here, R ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In Formula (Ia), G ^1a and G ^2a each independently represent a divalent aliphatic group having 1 to 20 carbon atoms which may have a substituent. In addition, in the aliphatic group, one or more -O-, -S-, -O-C (= O)-, -C (= O) -O-, -O-C per aliphatic group. ^{(= O) -O -, -} NR 2 -C (= O) -, - C (= O) -NR 2 -, - NR 2 -, or, -C (= O) - is be interposed Good. However, it excludes the case where two or more -O- or -S- are adjacent to each other. Here, R ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In the formula (Ia), Z ^1a and Z ^2a each independently represent an alkenyl group having 2 to 10 carbon atoms which may be substituted by a halogen atom.

In the formula (Ia), each of A ^2a and A ^3a independently represents a divalent C ^3-30 alicyclic hydrocarbon group which may have a substituent.

In the formula (Ia), each of A ^4a and A ^5a independently represents a divalent aromatic group having 6 to 30 carbon atoms which may have a substituent.

In Formula (Ia), k and l each independently represent 0 or 1.

However, in the formula (Ia), one or both of Z ^1a -Y ^7a -and -Y ^8a -Z ^2a are an acryloyloxy group.

Among the compounds represented by the following formula (I), particularly preferable examples of the reverse wavelength dispersion liquid crystal compound include a compound exhibiting liquid crystallinity. In the following description, the compound represented by the formula (I) may be referred to as “compound (I)” as appropriate.

Compound (I) is usually, as represented by the following formula, based ^{^{^{^{-Y 5 -A 4 -Y 3 - (}}}} A 2 -Y 1) n -A 1 - (Y 2 -A 3) m -Y 4 - It contains two mesogen skeletons of a main chain mesogen skeleton 1a consisting of A ⁵ -Y ^6- and a side chain mesogen skeleton 1b consisting of a group> A ¹ -C (Q ¹ ) = N-N (A ^x ) A ^y . In addition, the main chain mesogen skeleton 1a and the side chain mesogen skeleton 1b cross each other. The main chain mesogen skeleton 1a and the side chain mesogen skeleton 1b may be combined to form one mesogen skeleton, but in the present invention, they are divided into two mesogen skeletons.

The refractive index in the long axis direction of the main chain mesogen skeleton 1a is n1, and the refractive index in the long axis direction of the side chain mesogen skeleton 1b is n2. At this time, the absolute value of the refractive index n1 and the wavelength dispersion generally depend on the molecular structure of the main chain mesogen skeleton 1a. Further, the absolute value of the refractive index n2 and the wavelength dispersion generally depend on the molecular structure of the side chain mesogen skeleton 1b. Here, in the liquid crystal phase, the compound (I) usually performs rotational movement with the long axis direction of the main chain mesogen skeleton 1a as the axis of rotation, so the refractive indices n1 and n2 referred to here are the refractive index as a rotator Represents

The absolute value of the refractive index n1 is larger than the absolute value of the refractive index n2 derived from the molecular structures of the main chain mesogen skeleton 1a and the side chain mesogen skeleton 1b. Furthermore, the refractive indices n1 and n2 usually show forward wavelength dispersion. Here, the forward wavelength dispersive refractive index represents a refractive index in which the absolute value of the refractive index decreases as the measurement wavelength increases. The refractive index n1 of the main chain mesogen skeleton 1a exhibits a small degree of forward wavelength dispersion. Therefore, although the refractive index n1 measured by long wavelength becomes smaller than the refractive index measured by short wavelength, those differences are small. On the other hand, the refractive index n2 of the side chain mesogen skeleton 1b exhibits a large degree of forward wavelength dispersion. Therefore, the refractive index n2 measured at the long wavelength is smaller than the refractive index n2 measured at the short wavelength, and the difference between them is large. Therefore, when the measurement wavelength is short, the difference Δn between the refractive index n1 and the refractive index n2 is small, and when the measurement wavelength is long, the difference Δn between the refractive index n1 and the refractive index n2 becomes large. Thus, the compound (I) can exhibit reverse wavelength dispersion in-plane retardation when homogeneously oriented, which is derived from the main chain mesogen skeleton 1a and the side chain mesogen skeleton 1b.

In Formula (I), each of Y ¹ to Y ⁸ independently represents a chemical single bond, —O—, —S—, —O—C (= O) —, —C (= O) — O-, -O-C (= O) -O-, -NR ¹ -C (= O)-, -C (= O) -NR ^1- , -O-C (= O) -NR ^1- , -NR ¹ -C (= O) -O-, -NR ¹ -C (= O) -NR ^1- , -O-NR ^1- , or -NR ¹ -O-. Here, R ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In the formula (I), G ¹ and G ² each independently represent a divalent aliphatic group having 1 to 20 carbon atoms which may have a substituent. In addition, in the aliphatic group, one or more -O-, -S-, -O-C (= O)-, -C (= O) -O-, -O-C per aliphatic group. ^{(= O) -O -, -} NR 2 -C (= O) -, - C (= O) -NR 2 -, - NR 2 -, or, -C (= O) - is be interposed Good. However, it excludes the case where two or more -O- or -S- are adjacent to each other. Here, R ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In the formula (I), Z ¹ and Z ² each independently represent an alkenyl group having 2 to 10 carbon atoms which may be substituted by a halogen atom.

In the formula (I), A ^x represents an organic group having 2 to 30 carbon atoms, which has at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocycle. The “aromatic ring” is a cyclic structure having a broad aromaticity according to Huckel's rule, that is, a cyclic conjugated structure having (4n + 2) π electrons, and sulfur, oxygen, typified by thiophene, furan, benzothiazole, etc. It refers to a cyclic structure in which a lone electron pair of a heteroatom such as nitrogen participates in the π electron system to exhibit aromaticity.

As said aromatic hydrocarbon ring, a benzene ring, a naphthalene ring, an anthracene ring etc. are mentioned, for example. Examples of the aromatic heterocyclic ring include monocyclic aromatic heterocyclic rings such as pyrrole ring, furan ring, thiophene ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, pyrazole ring, imidazole ring, oxazole ring and thiazole ring; Benzothiazole ring, benzoxazole ring, quinoline ring, phthalazine ring, benzoimidazole ring, benzopyrazole ring, benzofuran ring, benzothiophene ring, thiazolopyridine ring, oxazolopyridine ring, thiazolopyrazine ring, oxazolopyrazine ring, thia And aromatic heterocyclic rings of fused rings such as a zolopyridazine ring, an oxazolopyridazine ring, a thiazolopyrimidine ring, and an oxazolopyrimidine ring.

In the formula (I), A ^y is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, A cycloalkyl group having 3 to 12 carbon atoms which may have a substituent, an alkynyl group having 2 to 20 carbon atoms which may have a substituent, -C (= O) -R ³ , -SO ₂ An organic group having 2 to 30 carbon atoms, which has at least one aromatic ring selected from the group consisting of -R ⁴ , -C (= S) NH-R ⁹ , or an aromatic hydrocarbon ring and an aromatic heterocycle Represent. Here, R ³ has an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, and a substituent. Or a cycloalkyl group having 3 to 12 carbon atoms or an aromatic hydrocarbon ring group having 5 to 12 carbon atoms. R ⁴ represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a phenyl group or a 4-methylphenyl group. R ⁹ is an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, carbon which may have a substituent And a cycloalkyl group of 3 to 12 or an aromatic group of 5 to 20 carbon atoms which may have a substituent. The aromatic ring which said A ^x and A ^y has may have a substituent. The A ^x and A ^y may be taken together to form a ring.

In Formula (I), A ¹ represents a trivalent aromatic group which may have a substituent.
In the formula (I), each of A ² and A ³ independently represents a divalent alicyclic hydrocarbon group having 3 to 30 carbon atoms which may have a substituent.
In the formula (I), each of A ⁴ and A ⁵ independently represents a divalent aromatic group having 6 to 30 carbon atoms which may have a substituent.
In the formula (I), Q ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent.
In the formula (I), m and n each independently represent 0 or 1.
However, in the formula (I), one or both of Z ¹ -Y ⁷ -and -Y ⁸ -Z ² are an acryloyloxy group.

Specific examples of the compound (I) include the compounds described in WO 2016/171169, WO 2017/057005, and WO 2016/190435. Also, the production of compound (I) can be carried out by the methods described in these documents.

Next, the reverse wavelength mesogen compound is described.
The reverse wavelength mesogen compound is a compound which does not exhibit liquid crystallinity alone, and in which the mixture for evaluation mixed with the liquid crystal compound for evaluation at a specific mixing ratio exhibits liquid crystallinity. As a liquid crystal compound for evaluation, a normal wavelength dispersive liquid crystal compound which is a liquid crystal compound which exhibits in-plane retardation of normal wavelength dispersion when homogeneously aligned is used. By using a normal wavelength dispersive liquid crystal compound as the liquid crystal compound for evaluation, it is possible to easily evaluate the wavelength dispersion of in-plane retardation of the reverse wavelength mesogen compound in the case where the mixture for evaluation is homogeneously aligned. Among them, as a liquid crystal compound for evaluation, a liquid crystal compound having a rod-like structure which can be a liquid crystal phase at 100 ° C. is preferable. As a specific example of the particularly preferable liquid crystal compound for evaluation, a forward wavelength dispersive liquid crystal compound (Paliocolor (registered trademark) LC242 (manufactured by BASF)) having a structure represented by the following formula (E1), a structure represented by the following formula (E2) And the forward wavelength dispersion liquid crystal compound etc. which it has. In the following formulae, Me represents a methyl group.

In addition, the mixing ratio of the reverse wavelength mesogen compound mixed with the liquid crystal compound for evaluation to obtain the above mixture for evaluation is usually 30 parts by weight with respect to a total of 100 parts by weight of the liquid crystal compound for evaluation and the reverse wavelength mesogen compound It is at least one of ̃70 parts by weight. Therefore, the liquid crystal compound exhibits the liquid crystallinity by mixing the reverse wavelength mesogen compound in the mixing ratio of 30 parts by weight to 70 parts by weight with respect to 100 parts by weight in total of the liquid crystal compound for evaluation and the reverse wavelength mesogen compound. As long as a mixture for evaluation is obtained, the reverse wavelength mesogen compound is mixed at another mixing ratio within the range of 30 parts by weight to 70 parts by weight with respect to a total of 100 parts by weight of the liquid crystal compound for evaluation and the reverse wavelength mesogen compound. The obtained mixture may not exhibit liquid crystallinity.

The liquid crystallinity of the mixture for evaluation can be confirmed by the following method.
The evaluation mixture is applied onto the substrate and dried to obtain a sample film comprising the substrate and a layer of the evaluation mixture. The sample film is placed on a hot stage. The sample film is heated while observing the sample film by a polarization microscope. When the phase transition to the liquid crystal phase of the layer of the mixture for evaluation is observed, it can be determined that the mixture for evaluation exhibits liquid crystallinity.

Further, when the evaluation mixture is homogeneously oriented, the reverse wavelength mesogen compound in the evaluation mixture exhibits in-plane retardation of reverse wavelength dispersion. Here, homogeneously aligning the mixture for evaluation means forming a layer of the mixture for evaluation and homogeneously aligning the liquid crystal compound for evaluation in the layer. Therefore, in the homogeneously oriented mixture for evaluation, the long axis direction of the mesogen skeleton of the molecules of the liquid crystal compound for evaluation is usually oriented in one direction parallel to the plane of the layer.

In addition, the in-plane retardation at a wavelength of 450 nm and 550 nm of the reverse wavelength mesogen compound contained in the mixture for evaluation is that the reverse wavelength mesogen compound in the homogeneously oriented evaluation mixture exhibits reverse wavelength dispersive in-plane retardation. It means that Re (450) and Re (550) satisfy Re (450) / Re (550) <1.00.

However, it is difficult to selectively measure only the in-plane retardation of the reverse wavelength mesogen compound in the layer of the mixture for evaluation. Therefore, using the fact that the liquid crystal compound for evaluation is a forward wavelength dispersion liquid crystal compound, it is confirmed that the reverse wavelength mesogen compound in the mixture for evaluation exhibits in-plane retardation of reverse wavelength dispersion by the following confirmation method. It can.
A liquid crystal layer containing a liquid crystal compound for evaluation as a forward wavelength dispersive liquid crystal compound is formed, and in the liquid crystal layer, the liquid crystal compound for evaluation is homogeneously aligned. Then, the ratio Re (X450) / Re (X550) of in-plane retardation Re (X450) and Re (X550) at the wavelengths 450 nm and 550 nm of the liquid crystal layer is measured.
Further, a layer of a mixture for evaluation containing the liquid crystal compound for evaluation and the reverse wavelength mesogen compound is formed, and the mixture for evaluation is homogeneously aligned in the layer of the mixture for evaluation. Then, the ratio Re (Y450) / Re (Y550) of in-plane retardations Re (Y450) and Re (Y550) at the wavelengths 450 nm and 550 nm of the layer of the mixture for evaluation is measured.
As a result of the measurement, the retardation ratio Re (Y450) / Re of the layer of the evaluation mixture containing the reverse wavelength mesogen compound is higher than the retardation ratio Re (X450) / Re (X550) of the liquid crystal layer not containing the reverse wavelength mesogen compound When (Y550) is small, it can be determined that the reverse wavelength mesogen compound exhibits an in-plane retardation of reverse wavelength dispersion.
Further, from the viewpoint of achieving the desired effects of the present invention better, in the above confirmation method, the ratio Re (X650) of the in-plane retardation Re (X550) and Re (X650) at the wavelengths 550 nm and 650 nm of the liquid crystal layer The ratio Re (Y650) / Re (Y550) of the in-plane retardation Re (Y550) and Re (Y650) of the layer of the mixture for evaluation at wavelengths 550 nm and 650 nm is larger than that of Re / X (550) preferable.

As the reverse wavelength mesogen compound, for example, a compound containing a main chain mesogen skeleton and a side chain mesogen skeleton bonded to the main chain mesogen skeleton in the molecule of the reverse wavelength mesogen compound can be used.

Furthermore, it is preferable that the reverse wavelength mesogen compound has polymerizability. Therefore, it is preferable that the reverse wavelength mesogen compound has a polymerizable group. As described above, when the reverse wavelength mesogen compound having a polymerizability is used, it is possible to easily fix the alignment state of the reverse wavelength mesogen compound by polymerization. Therefore, an optically anisotropic layer having stable optical properties can be easily obtained.

The molecular weight of the reverse wavelength mesogen compound, in the case of a monomer, is preferably 300 or more, more preferably 700 or more, particularly preferably 1000 or more, preferably 2000 or less, more preferably 1700 or less, particularly preferably 1500. It is below. The coatability of the coating liquid for forming an optically anisotropic layer can be made especially favorable because a reverse wavelength mesogen compound has the above molecular weight.

The above-mentioned reverse wavelength mesogen compounds may be used alone or in combination of two or more at an arbitrary ratio.

As a reverse wavelength mesogen compound, the compound which does not show liquid crystallinity among the compounds represented by said Formula (Ia) is mentioned, for example. As a preferable example of a reverse wavelength mesogen compound, the compound which does not show liquid crystallinity is mentioned among the compounds represented by said Formula (I). Among them, the following compounds may be mentioned as particularly preferable reverse wavelength mesogenic compounds.

Among the mesogen compounds described above, from the viewpoint of better expressing the desired effect of the present invention, a benzothiazole ring (a ring of the following formula (10A)); and a cyclohexyl ring (the following formula) What contains at least 1 sort (s) chosen from the group which consists of a ring of (10 B) and a phenyl ring (ring of following formula (10 C)); is preferable.

By polymerizing the mesogen compound, a polymer of the mesogen compound can be obtained. The specific method of polymerization is not particularly limited, and may be any method. Specifically, it can be carried out by irradiating a coating solution containing a mesogen compound with light. The details of this method will be described later.

The optically anisotropic layer contains a mesogenic compound in combination with the positive C polymer and the polymer of the mesogenic compound. Specifically, in addition to the polymer of the mesogen compound, the optically anisotropic layer may contain an unreacted mesogen compound remaining without polymerization. The proportion of the mesogenic compound is a proportion at which the degree of curing A falls within the specific range defined in the present application.

The proportion of the mesogen compound and the polymer thereof in the total solid content of the optically anisotropic layer is preferably 20% by weight or more, more preferably 30% by weight or more, still more preferably 35% by weight or more, particularly preferably 40% by weight or more Preferably it is 60 weight% or less, More preferably, it is 55 weight% or less, More preferably, it is 50 weight% or less, Especially preferably, it is 45 weight% or less. When the ratio of the mesogen compound and the polymer thereof is at least the lower limit value of the above range, the wavelength dispersion of the retardation Rth in the thickness direction of the optically anisotropic layer can be easily brought close to the reverse dispersion, and the above range In the optically anisotropic layer, the polymer of the mesogen compound can be dispersed uniformly, or the mechanical strength of the optically anisotropic layer can be increased.

[1.3. Optional ingredient]
The optically anisotropic layer may further contain optional components in combination with the positive C polymer, the mesogen compound and the polymer of the mesogen compound.

The optically anisotropic layer may contain a plasticizer. When the optically anisotropic layer contains a cellulose derivative as a positive C polymer, it is particularly preferable that the optically anisotropic layer contains a plasticizer in combination with the cellulose derivative. Examples of plasticizers include xylitol pentaacetate, xylitol pentapropionate, arabitol pentapropionate, triphenyl phosphate, polyesters containing succinic acid and diethylene glycol residues, and adipic acid residues and diethylene glycol residues And polyesters containing The proportion of the plasticizer is preferably 2.5% by weight or more, more preferably 10% by weight or more, preferably 25% by weight or less, more preferably 20% by weight, based on 100% by weight of the total of the positive C polymer and the plasticizer. It is at most weight percent.

[1.4. Properties of Optically Anisotropic Layer: Refractive Index]
The optically anisotropic layer satisfies the formula (2).
nz (A)> nx (A) ≧ ny (A) Formula (2)
nx (A), ny (A) and nz (A) are main refractive indices of the optically anisotropic layer. An optically anisotropic layer having such refractive indices nx (A), ny (A) and nz (A) can be used as a positive C film. Therefore, when the optically anisotropic layer is incorporated in a circularly polarizing plate and applied to an image display device, light that suppresses the reflection of external light or displays an image in the tilt direction of the display surface of the image display device It can be made transparent to polarized sunglasses. Furthermore, when the image display device is a liquid crystal display device, the viewing angle can usually be widened. Therefore, when the display surface of the image display device is viewed from the tilt direction, the visibility of the image can be enhanced.

Among them, it is preferable that the refractive index nx (A) and the refractive index ny (A) of the optically anisotropic layer have the same value or be close to each other. Specifically, the difference nx (A) -ny (A) between the refractive index nx (A) and the refractive index ny (A) is preferably 0.00000 to 0.00100, more preferably 0.00000 to 0. It is 00050, particularly preferably 0.00000 to 0.00020. When the refractive index difference nx (A) -ny (A) falls within the above range, the optical design in the case of providing the optically anisotropic layer in the image display device can be simplified, and other retardation films Adjustment of the bonding direction can be made unnecessary at the time of bonding with.

[1.5. Properties of Optically Anisotropic Layer: Curing Degree]
The optically anisotropic layer of the present invention satisfies the formula (3).
0.073 <A _C−H / A _{C = O} (mesogenic compound) <0.125 Formula (3)
In the formula (3), A _C-H is infrared absorption related to out-of-plane bending vibration of the CH bond of the acrylate structure of the mesogen compound in the infrared absorption spectrum of the optically anisotropic layer, _{C = O} (mesogen compound) is an infrared absorption of the stretching vibration of C = O bond of the acrylate structure of the mesogen compound in the infrared absorption spectrum of the optically anisotropic layer, and CCO of the acrylate structure of the mesogen compound It is the sum of infrared absorption of stretching vibration of C = O bond derived from bond. In the present application, the value A represented by A = A _C−H / A _{C = O 2} (mesogen compound) may be referred to as the degree of cure A of the mesogen compound.

The degree of cure A is a value determined depending on the amount of unreacted acrylate structure contained in the optically anisotropic layer, and the degree of cure A becomes a large value when the progress of the polymerization reaction is insufficient. The degree of curing A is a small value when the reaction of (1) is highly advanced. The degree of cure A is preferably greater than 0.073, more preferably greater than 0.076, and most preferably greater than 0.079. It is also preferably less than 0.125, more preferably less than 0.122, and most preferably less than 0.119. When the curing degree A in the optically anisotropic layer is equal to or more than the above lower limit value, a favorable color tone of the optically anisotropic layer can be realized. On the other hand, when the curing degree A in the optically anisotropic layer is equal to or less than the upper limit value, high durability of the optically anisotropic layer can be realized.

The infrared absorption spectrum of the optically anisotropic layer can be measured, for example, by total reflection measurement (ATR method).
As a measurement apparatus, Thermo Fisher SCIENTIFIC "Nicolet iS 5N" can be used. An infrared absorption spectrum is obtained as a graph showing the relationship between wave number and absorbance.

When the acrylate of the mesogen compound is polymerized, the vinyl group possessed by the acrylate structure is converted to an ethylene group, and the carbonyl group bonded to the vinyl group becomes a carbonyl group bonded to the ethylene group. The “C = O bond derived from the C = O bond of the acrylate structure of the mesogen compound” means a C カルボニル O bond of a carbonyl group bonded to an ethylene group that appears as a result of polymerization of the acrylate. For convenience of explanation, hereinafter, the "C-H bonds with acrylate structure mesogenic compound" is abbreviated as C-H _M, the "C = O bond of the acrylate structural mesogenic compound 'and C = O _M Abbreviated, "C = O bond derived from C = O bond of acrylate structure of mesogen compound" may be abbreviated as C = O _MD .

If the peak associated with the stretching vibration of C = O _M and the peak associated with the stretching vibration of C = O _MD do not separate and form a single peak, the infrared absorption of the single peak is determined by C = good as the sum of such infrared absorption on the stretching vibration of O according to the stretching vibration of _M infrared absorption and C = O _MD.

The value of _{_{A C-H / A C =}} O ( mesogenic compounds), the peak area according to the out-of-plane deformation vibration of _{C-H M} a (area _C-H), according to the stretching vibration of C = _{O M} It may use a value obtained by dividing _{_{(area C-H / area C}} = O) by the sum of the areas of the peaks according to the stretching vibration area and C _{= O MD} peaks (area _{C = O).}

In the infrared absorption spectrum, a peak applied to out-of-plane bending vibration of C—H _M usually appears around 810 cm ⁻¹ . In addition, a peak for stretching vibration of C = O _{M and} a peak for stretching vibration of C = O _MD usually appear in the vicinity of 1720 cm ⁻¹ .

When the components of the optically anisotropic layer have C = O bonds similar to them other than C = O _MD , they may not be distinguishable in the infrared absorption spectrum. In that case, a plurality of optically anisotropic layers having different proportions of components are prepared, and the effects of similar C = O bonds are eliminated by grasping the degree of influence of the proportions of the components on infrared absorption. Can do.

As a specific example of such determination, the case where a positive C polymer has a C = O bond similar to C = O _MD will be described.

In this example, when measuring the infrared absorption spectrum of the optically anisotropic layer, an infrared absorption A _{C = O} according to the stretching vibration of C = O bonds in such spectrum is obtained as the sum of the following items.
A _{C = O} (polymer): Infrared absorption of stretching vibration of C = O bond of positive C polymer.
A _{C = O} (mesogenic compound): Infrared absorption of stretching vibration of unreacted C = O _M and infrared radiation of stretching vibration of C = O bond (that is, C = O _MD ) of the polymer of the mesogen compound Sum with absorption.

That is, the following equation (A1) is established.
A _{C = O} = A _{C = O} (polymer) + A _{C = O} (mesogenic compound) Formula (A1)

The values of A C _{= O (polymer),} and A _{C = O (mesogenic} compound) is considered to be proportional to their weight ratio in the optically anisotropic layer. Therefore, the following formula (A2) is established for the ratio of each component in the optically anisotropic layer and the infrared absorption related to the stretching vibration of the C = O bond.

A _{C = O} = W (polymer) × a _{C = O} (polymer) + W (mesogen compound) × a _{C = O} (mesogen compound) (A2)

During the ceremony:
W (polymer) is a weight ratio of the positive C polymer to the sum of the weight of the positive C polymer and the weight of the mesogen compound and the polymer thereof in the optically anisotropic layer.
W (mesogen compound) is a weight ratio of the mesogen compound and the polymer thereof to the total of the weight of the positive C polymer and the weight of the mesogen compound and the polymer thereof in the optically anisotropic layer. That is, W (polymer) + W (mesogenic compound) = 1.
a _{C = O} (polymer) is a coefficient, and is an infrared absorption applied to stretching vibration of C = O bond per unit weight ratio of the positive C polymer.
a _{C = O} (mesogen compound) is a coefficient, and infrared absorption of stretching vibration of CCO bond of the acrylate structure per unit weight ratio of the mesogen compound and the polymer thereof, and C = of the acrylate structure It is the sum of infrared absorption of stretching vibration of C = O bond derived from O bond.

The values of a _{C = O} (polymer) and a _{C = O} (mesogen compound) are different from each other in the ratio of the weight of the positive C polymer to the weight of the mesogen compound and the polymer thereof. It can be determined by preparing and measuring the infrared absorption spectrum of each. Specifically, for each of a plurality of optically anisotropic layers different in W (polymer) and W (mesogen compound), A _{c = O} is measured. Thus, in several examples W (polymer), the value of W (mesogenic compounds) and A _{C = O} is known. From these values and the formula (A2), a _{C = O} (polymer) and a _{C = O} (mesogenic compound) such that the difference between the measured value and the theoretical value of A _{C = O} is minimized by the least squares method. calculate. From the calculated a _{C = O} (mesogenic compound) and known W (mesogenic compound), A _{C = O} (mesogenic compound) can be determined.

The value of the curing degree A can be controlled by adjusting the irradiation intensity and time of the active energy ray to be irradiated in the production process of the optically anisotropic layer.

[1.6. Properties of Optically Anisotropic Layer: Other]
The optically anisotropic layer usually satisfies the formula (4) and the formula (5).
0.50 <Rth (A450) / Rth (A550) <1.00 Formula (4)
1.00 ≦ Rth (A650) / Rth (A550) <1.25 Formula (5)
Where Rth (A450) is the retardation in the thickness direction of the optically anisotropic layer at a wavelength of 450 nm, and Rth (A550) is the retardation in the thickness direction of the optically anisotropic layer at a wavelength of 550 nm. A650) is the retardation in the thickness direction of the optically anisotropic layer at a wavelength of 650 nm.

Describing the formula (4) in detail, Rth (A450) / Rth (A550) is usually larger than 0.50, preferably larger than 0.60, more preferably larger than 0.65, and usually 1 It is less than .00, preferably less than 0.90, more preferably less than 0.85.

Further, the formula (5) will be described in detail. Rth (A650) / Rth (A550) is usually 1.00 or more, preferably 1.01 or more, more preferably 1.02 or more, and usually 1. It is less than 25, preferably less than 1.15, more preferably less than 1.10.

The optically anisotropic layer having the retardations Rth (A450), Rth (A550) and Rth (A650) in the thickness direction satisfying the formulas (4) and (5) has an opposite retardation Rth in the thickness direction. The wavelength dispersion is shown. As described above, the optically anisotropic layer in which the retardation Rth in the thickness direction exhibits reverse wavelength dispersion is incorporated in a circularly polarizing plate and applied to an image display device, the outer side in the inclination direction of the display surface of the image display device. The function of suppressing reflection of light or transmitting polarized sunglasses to light for displaying an image can be exhibited in a wide wavelength range. Furthermore, in the case where the image display device is a liquid crystal display device, the viewing angle can usually be effectively expanded. Therefore, the visibility of the image displayed on the display surface can be particularly effectively improved.

The optically anisotropic layer preferably satisfies the formula (6).
Re (A 590) ≦ 10 nm Formula (6)
However, Re (A 590) is the in-plane retardation of the optically anisotropic layer at a wavelength of 590 nm.
Describing the formula (6) in detail, Re (A 590) is preferably 0 nm to 10 nm, more preferably 0 nm to 5 nm, and particularly preferably 0 nm to 2 nm. When Re (A 590) falls within the above range, the optical design in the case of providing an optically anisotropic layer in an image display device can be simplified, and bonding is carried out at the time of bonding with another retardation film. It is not necessary to adjust the direction.

The optically anisotropic layer preferably satisfies the formula (7).
−200 nm ≦ Rth (A 590) ≦ -10 nm Formula (7)
However, Rth (A 590) is the retardation in the thickness direction of the optically anisotropic layer at a wavelength of 590 nm.
Describing the formula (7) in detail, Rth (A 590) is preferably -200 nm or more, more preferably -130 nm or more, particularly preferably -100 nm or more, preferably -10 nm or less, more preferably -30 nm Or less, particularly preferably −50 nm or less. When the optically anisotropic layer having such Rth (A 590) is incorporated in a circularly polarizing plate and applied to an image display device, the reflection of external light is suppressed in the inclination direction of the display surface of the image display device, The color change of the reflected light can be reduced, and the light for displaying the image can be transmitted through the polarized sunglasses. Furthermore, when the image display device is a liquid crystal display device, the viewing angle can usually be increased. Therefore, when the display surface of the image display device is viewed from the tilt direction, the visibility of the image can be enhanced.

The total light transmittance of the optically anisotropic layer is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more. The total light transmittance can be measured in the wavelength range of 400 nm to 700 nm using an ultraviolet and visible spectrometer.

The haze of the optically anisotropic layer is preferably 5% or less, more preferably 3% or less, particularly preferably 1% or less, and ideally 0%. The haze can be measured with a haze meter (for example, "Haze Guard II" manufactured by Toyo Seiki Seisaku-sho, Ltd.) according to JIS K 7136: 2000.

By satisfying the requirements such as the degree of curing of the optical anisotropy, the change in haze due to heating can be small. Specifically, the change ratio of the haze (after-heating haze value / initial haze value) before and after heating such as 85 ° C. for 500 hours may be small. The haze change ratio may be preferably 5.0 or less, more preferably 4.0 or less, and even more preferably 3.0 or less. The change in haze due to heating is usually a change in which the haze increases, but in some cases the haze may decrease. The lower limit of the haze change ratio may be 0.3 or more, 0.4 or more, or 0.5 or more.

The optically anisotropic layer can be made colorless or near in color by satisfying the requirements such as the degree of curing. Specifically, a positive C film having reverse wavelength dispersive Rth in the prior art often has a yellow color tone, while the optically anisotropic layer of the present invention may have such a low yellow color tone. More specifically, the optically anisotropic layer of the present invention preferably has a b ^* value in the L ^* a ^* b ^* color system of 2.5 or less, more preferably 2.2 or less, still more preferably 2 .0 or less. The lower limit of the b ^* value is ideally zero. The b ^* value can be observed by measuring the optically anisotropic layer with a spectrophotometer (for example, "V-550" manufactured by JASCO Corporation).

The thickness of the optically anisotropic layer can be appropriately adjusted so as to obtain a desired retardation. The specific thickness of the optically anisotropic layer is preferably 1.0 μm or more, more preferably 3.0 μm or more, preferably 50 μm or less, more preferably 40 μm or less, particularly preferably 30 μm or less.

[1.7. Method of producing optically anisotropic layer]
The optically anisotropic layer is
Step (a): providing a coating liquid containing a positive C polymer, a mesogen compound, and a solvent;
Step (b): coating the coating liquid on the support surface to obtain a coating liquid layer;
Step (c): Irradiating the coating liquid layer with light, and curing the coating liquid layer. Hereinafter, this manufacturing method will be described as a method of manufacturing the optically anisotropic layer of the present invention.

[1.7. Process (a): Preparation of Coating Liquid]
The process of preparing a coating liquid can be performed by mixing a positive C polymer, a mesogen compound, and a solvent. The ratio of the positive C polymer in the total solid content of the coating liquid and the ratio of the mesogen compound in the total solid content of the coating liquid are respectively the ratio of the positive C polymer in the optically anisotropic layer and the optically anisotropic layer It can adjust to the same range as the ratio of the mesogen compound in. When the production method of the present invention is carried out, a part of the mesogen compound in the coating liquid may be left unreacted in the optically anisotropic layer without being polymerized. However, when the curing degree A is within the range specified in the present application, the proportion of such unreacted mesogen compound is small.

As a solvent, an organic solvent is usually used. Examples of such organic solvents include hydrocarbon solvents such as cyclopentane and cyclohexane; ketone solvents such as cyclopentanone, cyclohexanone, methyl ethyl ketone, acetone, methyl isobutyl ketone and N-methyl pyrrolidone; acetic acid esters such as butyl acetate and amyl acetate Solvents: Halogenated hydrocarbon solvents such as chloroform, dichloromethane, dichloroethane, etc .; Ether solvents such as 1,4-dioxane, cyclopentyl methyl ether, tetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 1,2-dimethoxyethane, etc., toluene, xylene And aromatic hydrocarbon solvents such as mesitylene; and mixtures thereof. The boiling point of the solvent is preferably 60 ° C. to 250 ° C., and more preferably 60 ° C. to 150 ° C., from the viewpoint of excellent handleability. Moreover, a solvent may be used individually by 1 type, and may be used combining 2 or more types by arbitrary ratios.

The amount of the solvent is preferably adjusted so that the solid content concentration of the coating liquid can be in the desired range. The solid content concentration of the coating liquid is preferably 6% by weight or more, more preferably 8% by weight or more, particularly preferably 10% by weight or more, preferably 20% by weight or less, more preferably 18% by weight or less, particularly Preferably it is 15 weight% or less. By setting the solid content concentration of the coating liquid within the above range, an optically anisotropic layer having desired optical properties can be easily formed.

The coating liquid for forming the optically anisotropic layer may contain any component in combination with the positive C polymer, the mesogen compound and the solvent. In addition, as the optional components, one type may be used alone, or two or more types may be used in combination at an optional ratio.

The coating liquid may contain a polymerization initiator as an optional component. The type of the polymerization initiator can be appropriately selected according to the type of the polymerizable group contained in the polymerizable compound in the coating liquid. Here, the polymerizable compound is a generic term for compounds having polymerizability. Among them, a photopolymerization initiator is preferred. As a photoinitiator, a radical polymerization initiator, an anionic polymerization initiator, a cationic polymerization initiator etc. are mentioned. As a specific example of a commercially available photopolymerization initiator, trade name: Irgacure 907, trade name: Irgacure 184, trade name: Irgacure 369, trade name: Irgacure 651, trade name: Irgacure 819, trade name: Irgacure 907, made by BASF AG Name: Irgacure 379, trade name: Irgacure 379 EG, trade name: Irgacure OXE 02, and trade name: Irgacure OXE 04; trade name: Adeka Optomer N 1919 manufactured by ADEKA Corporation. Moreover, a polymerization initiator may be used individually by 1 type, and may be used combining 2 or more types by arbitrary ratios.

The amount of a polymerization initiator such as a photopolymerization initiator in the coating liquid may be adjusted to obtain a desired degree of cure A. The ratio of the polymerization initiator to 100 parts by weight of the mesogen compound in the coating liquid is preferably 1 part by weight or more, more preferably 2 parts by weight or more, preferably 10 parts by weight or less, more preferably 8 parts by weight or less is there.

The coating liquid may contain a crosslinking agent as an optional component. The type of polymerization initiator can be appropriately selected according to the type of polymerizable compound in the coating liquid. Examples of the crosslinking agent include trade name: A-TMPT (trimethylolpropane triacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.). One type of crosslinking agent may be used alone, or two or more types may be used in combination in an arbitrary ratio.

The amount of the crosslinking agent in the coating liquid can be adjusted to obtain an optically anisotropic layer having desired physical properties. The ratio of the crosslinking agent to 100 parts by weight of the mesogen compound in the coating liquid is preferably 1 part by weight or more, more preferably 2 parts by weight or more, preferably 10 parts by weight or less, more preferably 8 parts by weight or less .

The coating liquid contains, as optional components, metals, metal complexes, dyes, pigments, fluorescent materials, phosphorescent materials, leveling agents, thixo agents, gelling agents, polysaccharides, surfactants, ultraviolet absorbers, infrared absorbers, Optional additives such as antioxidants, ion exchange resins, metal oxides such as titanium oxide may be included. The ratio of such optional additives is preferably 0.1 parts by weight to 20 parts by weight for each 100 parts by weight of the positive C polymer.

The coating liquid preferably does not exhibit liquid crystallinity. By using a coating liquid that does not exhibit liquid crystallinity, the dispersion of the positive C polymer and the mesogen compound can be made favorable in the optically anisotropic layer. Moreover, generation | occurrence | production of the orientation nonuniformity of the mesogen compound under the influence of fluctuation of air, such as a drying wind, can be suppressed by using the coating liquid which does not have liquid crystallinity.

[1.7.2. Process (b): Coating]
In the step of applying the coating liquid on the support surface to obtain a coating liquid layer, any surface capable of supporting the coating liquid layer can be used as the support surface. As the supporting surface, in order to improve the surface state of the optically anisotropic layer, a flat surface having no concave portion and no convex portion is generally used. As said support surface, it is preferable to use the surface of a elongate base material. When using a long base material, it is possible to apply a coating fluid continuously on the base material conveyed continuously. Therefore, by using a long base material, the optically anisotropic layer can be manufactured continuously, and therefore, the productivity can be improved.

As a substrate, usually, a substrate film can be used. As a base film, the film which can be used as a base of an optical laminated body can be selected suitably, and can be used. Above all, a multilayer film comprising a substrate film and an optically anisotropic layer can be used as an optical film, and from the viewpoint of eliminating the need for peeling of the optically anisotropic layer from the substrate film, the substrate film is transparent. Films are preferred. Specifically, the total light transmittance of the base film is preferably 80% or more, more preferably 85% or more, and particularly preferably 88% or more.

The material of the base film is not particularly limited, and various resins can be used. Examples of the resin include resins containing various polymers. Examples of the polymer include alicyclic structure-containing polymers, cellulose esters, polyvinyl alcohols, polyimides, UV transmitting acrylics, polycarbonates, polysulfones, polyether sulfones, epoxy polymers, polystyrenes, and combinations thereof. Among these, from the viewpoints of transparency, low hygroscopicity, dimensional stability, and lightness, an alicyclic structure-containing polymer and a cellulose ester are preferable, and an alicyclic structure-containing polymer is more preferable.

The alicyclic structure-containing polymer is a polymer having an alicyclic structure in the repeating unit, and is usually an amorphous polymer. As the alicyclic structure-containing polymer, any of a polymer containing an alicyclic structure in its main chain and a polymer containing an alicyclic structure in its side chain can be used.
As an alicyclic structure, although a cycloalkane structure, a cycloalkene structure, etc. are mentioned, a cycloalkane structure is preferable from a viewpoint of heat stability etc., for example.
The number of carbon atoms constituting the repeating unit of one alicyclic structure is not particularly limited, but is preferably 4 or more, more preferably 5 or more, particularly preferably 6 or more, preferably 30 or less, Preferably it is 20 or less, Especially preferably, it is 15 or less.

The proportion of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer may be appropriately selected depending on the purpose of use, but is preferably 50% by weight or more, more preferably 70% by weight or more, particularly preferably It is 90% by weight or more. By increasing the number of repeating units having an alicyclic structure as described above, the heat resistance of the substrate film can be increased.

The alicyclic structure-containing polymer includes, for example, (1) norbornene polymer, (2) monocyclic cyclic olefin polymer, (3) cyclic conjugated diene polymer, (4) vinyl alicyclic hydrocarbon polymer, And these hydrogen additives and the like. Among these, from the viewpoint of transparency and moldability, norbornene polymers are more preferable.

As the norbornene polymer, for example, a ring-opening polymer of norbornene monomer, a ring-opening copolymer of norbornene monomer and another monomer capable of ring-opening copolymerization, and hydrogenated products thereof; addition polymer of norbornene monomer, And addition copolymers of norbornene monomers with other monomers copolymerizable, and the like. Among these, from the viewpoint of transparency, a ring-opened polymer hydrogenated substance of norbornene monomer is particularly preferable.

The above-mentioned alicyclic structure-containing polymer can be selected from known polymers such as those disclosed in JP-A-2002-321302.

In the case of using a resin containing an alicyclic structure-containing polymer as the material of the substrate film, the thickness of the substrate film is preferably 1 μm to 1 in view of facilitating improvement of productivity, thinning and weight reduction. It is 1000 μm, more preferably 5 μm to 300 μm, and particularly preferably 30 μm to 100 μm.

The resin containing an alicyclic structure-containing polymer may consist only of an alicyclic structure-containing polymer, but may contain any compounding agent as long as the effects of the present invention are not significantly impaired. The proportion of the alicyclic structure-containing polymer in the resin containing the alicyclic structure-containing polymer is preferably 70% by weight or more, and more preferably 80% by weight or more.
As a preferable specific example of resin containing an alicyclic structure containing polymer, "Zeonor 1420" and "Zeonor 1420R" by Nippon Zeon Co., Ltd. can be mentioned.

Examples of coating methods for the coating liquid include curtain coating, extrusion coating, roll coating, spin coating, dip coating, bar coating, spray coating, slide coating, print coating, gravure coating Methods include die coating, gap coating, and dipping. The thickness of the coating liquid to be coated can be appropriately set in accordance with the desired thickness required for the optically anisotropic layer.

[1.7.3. Drying]
Before the step (c) after the step (b), a step of drying the coating liquid layer is carried out, if necessary. By drying, the solvent is removed from the coating liquid layer, and the orientation of the solid content of the coating liquid can be stabilized. As a result, the step (c) can be performed in a state where the solid content of the coating liquid is stable. As a specific method of drying, any method such as heat drying, reduced pressure drying, heated reduced pressure drying, natural drying, etc. may be adopted.

The method for producing an optically anisotropic layer of the present invention can produce an optically anisotropic layer by a simple operation of coating a coating solution containing a combination of a positive C polymer and a mesogen compound and curing. Therefore, the alignment film as described in Patent Document 1 is unnecessary. Therefore, operations such as adjustment of the compatibility between the reverse wavelength dispersion liquid crystal and the alignment film and formation of the alignment film are not necessary, so that the optically anisotropic layer can be easily manufactured.

Furthermore, the coating liquid containing the positive C polymer and the mesogen compound in combination can suppress the occurrence of the alignment unevenness of the mesogen compound due to the influence of the fluctuation of air during drying. Therefore, it is possible to easily obtain an optically anisotropic layer in which the alignment state is uniform in a wide range in the in-plane direction, so it is easy to obtain an optically anisotropic layer excellent in the surface state. Therefore, it is possible to suppress the white turbidity due to the alignment unevenness of the optically anisotropic layer.

[1.7.4. Process (c): light irradiation]
By performing the step of light irradiation, a part of the acrylate structure of the mesogen compound is polymerized to be a polymer of the mesogen compound. By such polymerization, an optically anisotropic layer containing a positive C polymer and a polymer of a mesogenic compound can be formed. The irradiation of light to the coating liquid layer may be appropriately selected from methods suitable for the properties of the components contained in the coating liquid, such as the polymerizable compound and the polymerization initiator. The light to be irradiated may include light such as visible light, ultraviolet light, and infrared light. Among them, a method of irradiating ultraviolet light is preferable because the operation is simple.

Ultraviolet irradiation intensity is preferably in the range of ^{0.1mW / cm 2 ~ 1000mW / cm} 2, more preferably from ^{0.5mW / cm 2 ~ 600mW / cm} 2. The ultraviolet irradiation time is preferably in the range of 1 second to 300 seconds, more preferably in the range of 3 seconds to 100 seconds. The integrated ultraviolet light quantity (mJ / cm ² ) is determined by the ultraviolet irradiation intensity (mW / cm ² ) × irradiation time (seconds). Preferred integrated light quantity ^is 600mJ / cm 2 ~ 5000mJ / cm 2. As an ultraviolet irradiation light source, a high pressure mercury lamp, a metal halide lamp, and a low pressure mercury lamp can be used. It is preferable to carry out the step (c) under an inert gas atmosphere such as a nitrogen atmosphere because the residual monomer ratio tends to be reduced.

The method of producing the optically anisotropic layer may include any step other than the steps described above. For example, the step of peeling the optically anisotropic layer from the substrate may be included.

[2. Multilayer for transfer]
The transfer multilayer of the present invention comprises a substrate and the above-mentioned optically anisotropic layer. Here, the transfer multilayer is a member including a plurality of layers, and a part of the plurality of layers is transferred to provide a product including the part of the layers. is there. In the transfer multilayer of the present invention, the optically anisotropic layer is subjected to the production of the above-mentioned product.

As the substrate, the same one as the substrate described in the method for producing an optically anisotropic layer can be used. Among them, as the substrate, those which can be peeled off are preferable. A transfer multilayer provided with such a substrate can be produced by carrying out the above-mentioned method for producing an optically anisotropic layer using a substrate.

The transfer multilayer may be used to produce an optical film. For example, an optical film provided with an optically anisotropic layer and a resin film can be manufactured by peeling the base after laminating the optically anisotropic layer of the multilayer for transfer and the resin film.

[3. Optically anisotropic laminate]
The optically anisotropic laminate of the present invention comprises the above-described optically anisotropic layer and a retardation layer.

[3.1. Optically anisotropic layer in optically anisotropic laminate]
As the optically anisotropic layer of the optically anisotropic laminate, those described above are used. However, it is preferable that the optically anisotropic layer in the optically anisotropic laminate satisfy the following formulas (12) and (13).
Re (A 590) ≦ 10 nm Formula (12)
−110 nm ≦ Rth (A 590) ≦ −20 nm Formula (13)
The definitions of Re (A 590) and Rth (A 590) are as described above.

Describing the formula (12) in detail, Re (A 590) is preferably 0 nm to 10 nm, more preferably 0 nm to 5 nm, and particularly preferably 0 nm to 2 nm. When Re (A 590) falls within the above range, the optical design in the case of providing the optically anisotropic laminate in an image display device can be simplified.

Further, to describe the formula (13) in detail, Rth (A 590) is preferably -110 nm or more, more preferably -100 nm or more, preferably -20 nm or less, more preferably -40 nm or less, particularly preferably -50 nm or less. An optically anisotropic laminate having an optically anisotropic layer having such Rth (A 590) is incorporated in a circularly polarizing plate and applied to an image display device, in the inclination direction of the display surface of the image display device. The function of suppressing the reflection of external light and transmitting light that displays an image can be effectively exhibited. Therefore, when the display surface of the image display device is viewed from the inclined direction, the visibility of the image can be effectively enhanced.

[3.2. Retardation layer in optically anisotropic laminate]
[3.2.1. Optical Properties of Retardation Layer]
The retardation layer is a layer satisfying the formula (8).
nx (B)> ny (B) ≧ nz (B) Formula (8)
However, nx (B), ny (B) and nz (B) are the main refractive indexes of the said phase difference layer. An optically anisotropic laminate having such a retardation layer can be used to produce a circularly polarizing plate by combining it with a linear polarizer. This circularly polarizing plate is provided on the display surface of the image display device, so that reflection of external light can be suppressed or light for displaying an image can be transmitted through polarized sunglasses when the display surface is viewed from the front direction. Image visibility can be enhanced.

Among them, it is preferable that the refractive index ny (B) of the retardation layer and the refractive index nz (B) have the same value or be close to each other. Specifically, the absolute value | ny (B) −nz (B) | of the difference between the refractive index ny (B) and the refractive index nz (B) is preferably 0.00000 to 0.00100, more preferably 0. And particularly preferably 0.00000 to 0.00020. When the absolute value | ny (B) −nz (B) | of the refractive index difference falls within the above range, the optical design in the case where the optically anisotropic laminate is provided in the image display device can be simplified.

The retardation layer preferably satisfies the formula (11).
110 nm ≦ Re (B 590) ≦ 170 nm Formula (11)
However, Re (B 590) is the in-plane retardation of the retardation layer at a wavelength of 590 nm.

Describing the formula (11) in detail, Re (B 590) is preferably 110 nm or more, more preferably 120 nm or more, particularly preferably 130 nm or more, preferably 170 nm or less, more preferably 160 nm or less, particularly preferably 150 nm or less. An optically anisotropic laminate having such a retardation layer having Re (B 590) can be combined with a linear polarizer to obtain a circularly polarizing plate. By providing the circularly polarizing plate on the display surface of the image display device, reflection of external light can be suppressed or light for displaying an image can be transmitted through polarized sunglasses when the display surface is viewed from the front direction. As it can, it is possible to improve the visibility of the image.

The retardation layer preferably satisfies Formulas (9) and (10).
0.75 <Re (B450) / Re (B550) <1.00 Formula (9)
1.01 <Re (B650) / Re (B550) <1.25 Formula (10)
However, Re (B450) is an in-plane retardation of the retardation layer at a wavelength of 450 nm, Re (B550) is an in-plane retardation of the retardation layer at a wavelength of 550 nm, and Re (B650) is In-plane retardation of the retardation layer at a wavelength of 650 nm.

Describing the formula (9) in detail, Re (B450) / Re (B550) is preferably more than 0.75, more preferably more than 0.78, particularly preferably more than 0.80, and Preferably it is less than 1.00, more preferably less than 0.95, particularly preferably less than 0.90.

Describing the formula (10) in detail, Re (B650) / Re (B550) is preferably more than 1.01, preferably more than 1.02, particularly preferably more than 1.04, and preferably Is less than 1.25, more preferably less than 1.22, particularly preferably less than 1.19.

In the retardation layer having in-plane retardations Re (B450), Re (B550) and Re (B650) satisfying the formulas (9) and (10), the in-plane retardation Re has inverse wavelength dispersion. Show. As described above, the optically anisotropic laminate having the retardation layer in which the in-plane retardation Re exhibits reverse wavelength dispersion is incorporated in the circularly polarizing plate and applied to the image display device. In the front direction, the function of suppressing the reflection of external light or transmitting the polarized sunglasses to the light for displaying an image can be exhibited in a wide wavelength range. Therefore, the visibility of the image displayed on the display surface can be particularly effectively improved.

The slow axis direction in the plane of the retardation layer is arbitrary, and can be arbitrarily set according to the application of the optically anisotropic laminate. Among them, when the optically anisotropic laminate is a long film, the angle between the slow axis of the retardation layer and the film width direction is preferably more than 0 ° and less than 90 °. In one embodiment, an angle between the in-plane slow axis of the retardation layer and the film width direction is preferably 15 ° ± 5 °, 22.5 ° ± 5 °, 45 ° ± 5 °, or 75 °. ° ± 5 °, more preferably 15 ° ± 4 °, 22.5 ° ± 4 °, 45 ° ± 4 °, or 75 ° ± 4 °, even more preferably 15 ° ± 3 °, 22.5 ° ± It may be a specific range such as 3 °, 45 ° ± 3 °, or 75 ° ± 3 °. By having such an angular relationship, the optically anisotropic laminate is attached to a long linear polarizer by roll-to-roll, and efficient production of a circularly polarizing plate becomes possible.

The total light transmittance of the retardation layer is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more. The haze of the retardation layer is preferably 5% or less, more preferably 3% or less, particularly preferably 1% or less, and ideally 0%.

[3.2.2. Stretched Film Layer as Retardation Layer]
A stretched film layer can be used as the retardation layer as described above. When a stretched film layer is used as the retardation layer, the stretched film layer may contain a resin which is a material of the base film described in the method for producing an optically anisotropic layer. A film layer containing such a resin can exhibit optical properties such as retardation by being subjected to a stretching treatment. Among them, the stretched film layer preferably contains an alicyclic structure-containing polymer.

The stretching direction of the stretched film layer is arbitrary. Therefore, the stretching direction may be a longitudinal direction, a width direction, or an oblique direction. Furthermore, among these stretching directions, stretching may be performed in two or more directions. Here, the oblique direction refers to the in-plane direction of the film, which is not parallel to any of the longitudinal direction and the width direction.

Among them, the stretched film layer is preferably a diagonally stretched film layer. That is, the stretched film layer is preferably a long film and a film stretched in a direction nonparallel to any of the longitudinal direction and the width direction of the film. Specifically, the angle between the film width direction and the stretching direction in the case of the obliquely stretched film layer may be more than 0 ° and less than 90 °. By using such an obliquely stretched film layer as a retardation layer, an optically anisotropic laminate can be bonded to a long linear polarizer by roll-to-roll, and efficient production of a circularly polarizing plate becomes possible. .

The angle between the stretching direction and the film width direction is preferably 15 ° ± 5 °, 22.5 ± 5 °, 45 ° ± 5 °, or 75 ° ± 5 °, more preferably 15 ° ± 4 °, 22 .5 ° ± 4 °, 45 ° ± 4 °, or 75 ° ± 4 °, and even more preferably 15 ° ± 3 °, 22.5 ° ± 3 °, 45 ° ± 3 °, or 75 ° ± 3 ° It can be a specific range such as By having such an angular relationship, the optically anisotropic laminate can be made a material that enables efficient production of a circularly polarizing plate.

Furthermore, the stretched film layer preferably has a multilayer structure including a plurality of layers. The stretched film layer having a multilayer structure can exhibit various properties by the combination of the functions of the layers included in the stretched film layer. For example, the stretched film layer includes a first outer layer made of a resin containing a polymer, an intermediate layer made of a resin containing a polymer and a UV absorber, and a second outer layer made of a resin containing a polymer in this order It is preferable to have. Under the present circumstances, although the polymer contained in each layer may differ, it is preferable that it is the same. The stretched film layer comprising such first outer layer, intermediate layer and second outer layer can suppress the transmission of ultraviolet light. In addition, since the first outer layer and the second outer layer are provided on both sides of the intermediate layer, the bleeding out of the ultraviolet absorber can be suppressed.

The amount of the UV absorber in the resin contained in the intermediate layer is preferably 3% by weight or more, more preferably 4% by weight or more, particularly preferably 5% by weight or more, preferably 20% by weight or less, more preferably 18%. % By weight or less, particularly preferably 16% by weight or less. When the amount of the ultraviolet absorber is at least the lower limit value of the above range, the ability of the stretched film layer to block the transmission of ultraviolet rays can be particularly enhanced, and by being at the upper limit value of the above range, the stretched film layer Transparency to visible light can be enhanced.

The thickness of the intermediate layer is preferably set such that the ratio represented by “the thickness of the intermediate layer” / “the thickness of the entire stretched film layer” falls within a specific range. The specific range is preferably 1/5 or more, more preferably 1/4 or more, particularly preferably 1/3 or more, preferably 80/82 or less, more preferably 79/82 or less, particularly preferably It is 78/82 or less. When the ratio is at least the lower limit of the above range, the ability of the stretched film layer to block the transmission of ultraviolet light can be particularly enhanced, and by being at the upper limit or less of the above range, the thickness of the stretched film layer It can be thin.

The thickness of the stretched film layer as the retardation layer is preferably 10 μm or more, more preferably 13 μm or more, particularly preferably 15 μm or more, preferably 60 μm or less, more preferably 58 μm or less, particularly preferably 55 μm or less. When the thickness of the stretched film layer is not less than the lower limit of the above range, desired retardation can be expressed, and when it is not more than the upper limit of the above range, a thin film can be formed.

The stretched film layer can be produced, for example, by a method including the steps of preparing a film layer before stretching and stretching the prepared film layer before stretching.

The film layer before stretching can be produced, for example, by molding a resin to be a material of the stretched film layer by a suitable molding method. As a molding method, a cast molding method, an extrusion molding method, an inflation molding method etc. are mentioned, for example. Among them, the melt extrusion method which does not use a solvent can reduce the amount of residual volatile component efficiently, and is preferable from the viewpoints of the global environment and the working environment, and from the viewpoint of excellent manufacturing efficiency. The melt extrusion method may, for example, be an inflation method using a die, and a method using a T-die is preferable among them in terms of excellent productivity and thickness accuracy.

When producing a stretched film layer having a multilayer structure, one having a multilayer structure is usually prepared as a film layer before stretching. Thus, the pre-stretched film layer having a multilayer structure can be produced, for example, by molding a resin corresponding to each layer included in the multilayer structure by a molding method such as a coextrusion method and a co-casting method. Among these molding methods, co-extrusion method is preferable because it is excellent in production efficiency and hardly retains volatile components in the film. Examples of the co-extrusion method include co-extrusion T-die method, co-extrusion inflation method, co-extrusion lamination method and the like. Among them, the co-extrusion T-die method is preferable. The co-extrusion T-die method includes a feed block method and a multi-manifold method, and the multi-manifold method is particularly preferable in that variations in thickness can be reduced.

By molding the resin as described above, a long unstretched film can be obtained. A stretched film layer is obtained by stretching the film before stretching. Stretching is usually performed continuously while conveying the film before stretching in the longitudinal direction. Under the present circumstances, although the extending | stretching direction may be a longitudinal direction of a film, and may be width direction, it is preferable that it is an oblique direction. Further, the stretching may be free uniaxial stretching in which a restraining force is not applied in the direction other than the stretching direction, or may be stretching in which a restraining force is applied in the direction other than the stretching direction. These stretching may be performed using any stretching machine such as a roll stretcher or a tenter stretcher.

The stretching ratio is preferably 1.1 times or more, more preferably 1.15 times or more, particularly preferably 1.2 times or more, preferably 3.0 times or less, more preferably 2.8 times or less, in particular Preferably it is 2.6 times or less. The refractive index in the stretching direction can be increased by setting the stretching ratio to the lower limit value or more of the above range. In addition, by setting the upper limit value or less, the slow axis direction of the stretched film layer can be easily controlled.

The stretching temperature is preferably Tg-5 ° C. or more, more preferably Tg-2 ° C. or more, particularly preferably Tg ° C. or more, preferably Tg + 40 ° C. or less, more preferably Tg + 35 ° C. or less, particularly preferably Tg + 30 ° C. or less is there. Here, “Tg” represents the highest temperature among the glass transition temperatures of the polymer contained in the film layer before stretching. By setting the stretching temperature within the above range, the molecules contained in the film layer before stretching can be reliably oriented, so that a stretched film layer capable of functioning as a retardation layer having desired optical properties can be easily obtained. Can.

[3.2.3. Liquid Crystal Layer as Retardation Layer]
As the retardation layer as described above, a liquid crystal layer containing a liquid crystal compound (hereinafter, sometimes referred to as “liquid crystal compound for retardation layer” as appropriate) in which the alignment state may be fixed can be used. Under the present circumstances, it is preferable to use the said reverse wavelength dispersion liquid crystal compound which carried out homogeneous orientation as a liquid crystal compound for retardation layers. Thereby, the same advantages as described in the section of the optically anisotropic layer can be obtained in the retardation layer. Among them, it is particularly preferable that the liquid crystal layer as the retardation layer contains a liquid crystal compound represented by the following formula (II) which may be fixed in the alignment state.

In the above formula (II), Y ¹ to Y ⁸ , G ¹ , G ² , Z ¹ , Z ² , A ^x , A ^y , A ¹ to A ⁵ , Q ¹ , m and n are as in formula (I) Represents the same meaning as the meaning. Thus, the liquid crystal compound represented by the formula (II) represents the same compound as the liquid crystal compound represented by the formula (I).
However, in Formula (I), one or both of Z ¹ -Y ⁷ -and -Y ⁸ -Z ² are an acryloyloxy group, while in Formula (II), both of them are other than an acryloyloxy group It may be a group of

The thickness of the liquid crystal layer as the retardation layer is not particularly limited, and can be appropriately adjusted so that the characteristics such as retardation can be in the desired range. The specific thickness of the liquid crystal layer is preferably 0.5 μm or more, more preferably 1.0 μm or more, preferably 10 μm or less, more preferably 7 μm or less, and particularly preferably 5 μm or less.

The liquid crystal layer as a retardation layer is, for example, a step of preparing a liquid crystal composition containing a liquid crystal compound for retardation layer; a step of applying a liquid crystal composition on a support to obtain a layer of liquid crystal composition; And a step of aligning the liquid crystal compound for retardation layer contained in the layer of the liquid crystal composition.

In the step of preparing a liquid crystal composition, a liquid crystal composition is usually obtained by mixing a liquid crystal compound for retardation layer and an optional component used as needed.

The liquid crystal composition may contain a polymerizable monomer as an optional component. The term "polymerizable monomer" refers to a compound other than the above-mentioned liquid crystal compound for retardation layer, among compounds having polymerization ability and capable of acting as a monomer. As the polymerizable monomer, for example, one having one or more polymerizable groups per molecule can be used. When the polymerizable monomer is a crosslinkable monomer having two or more polymerizable groups per molecule, crosslinkable polymerization can be achieved. Examples of such a polymerizable group can include the same groups as the groups Z ¹ -Y ⁷ -and Z ² -Y ⁸ -or a part thereof in compound (I), and more specifically, for example, acryloyl group And methacryloyl groups and epoxy groups. In addition, one type of polymerizable monomer may be used alone, or two or more types may be used in combination in an arbitrary ratio.
The proportion of the polymerizable monomer in the liquid crystal composition is preferably 1 part by weight to 100 parts by weight, more preferably 5 parts by weight to 50 parts by weight with respect to 100 parts by weight of the liquid crystal compound for retardation layer.

The liquid crystal composition may contain a photopolymerization initiator as an optional component. As a polymerization initiator, the same thing as the polymerization initiator which the coating liquid for manufacture of an optically anisotropic layer may contain is mentioned, for example. Moreover, a polymerization initiator may be used individually by 1 type, and may be used combining 2 or more types by arbitrary ratios.
In the liquid crystal composition, the proportion of the polymerization initiator is preferably 0.1 to 30 parts by weight, more preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the polymerizable compound.

The liquid crystal composition may contain a surfactant as an optional component. As surfactant, nonionic surfactant is preferable. A commercial item can be used as nonionic surfactant. For example, a nonionic surfactant which is an oligomer having a molecular weight of several thousand may be used. Specific examples of these surfactants include “PF-151N”, “PF-636”, “PF-6320”, “PF-656”, “PF-6520”, “PF-3320” of PolyFox from OMNOVA. , "PF-651", "PF-652"; Neos Futagent "FTX-209F", "FTX-208G", "FTX-204D", "601 AD"; Seimi Chemical's Surfron "KH-40" , "S-420" and the like can be used. Moreover, surfactant may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
In the liquid crystal composition, the proportion of the surfactant is preferably 0.01 parts by weight to 10 parts by weight, more preferably 0.1 parts by weight to 2 parts by weight, with respect to 100 parts by weight of the polymerizable compound.

The liquid crystal composition may contain a solvent as an optional component. As a solvent, the same thing as the solvent which the coating liquid for manufacture of an optically anisotropic layer may contain is mentioned, for example. Moreover, a solvent may be used individually by 1 type, and may be used combining 2 or more types by arbitrary ratios.
The proportion of the solvent in the liquid crystal composition is preferably 100 parts by weight to 1000 parts by weight with respect to 100 parts by weight of the polymerizable compound.

The liquid crystal composition may further contain, as optional components, metals, metal complexes, dyes, pigments, fluorescent materials, phosphorescent materials, leveling agents, thixo agents, gelling agents, polysaccharides, ultraviolet absorbers, infrared absorbers, antioxidants Additives, such as an agent, ion exchange resin, and metal oxides such as titanium oxide may be included. The proportion of such additives is preferably 0.1 parts by weight to 20 parts by weight with respect to 100 parts by weight of the polymerizable compound.

After the liquid crystal composition as described above is prepared, the liquid crystal composition is coated on a support to obtain a layer of the liquid crystal composition. As a support, it is preferable to use a long support. In the case of using a long support, it is possible to continuously coat the liquid crystal composition on the support which is continuously transported. Therefore, since the liquid crystal layer as a phase difference layer can be manufactured continuously by using a long support, productivity can be improved.

When the liquid crystal composition is coated on a support, an appropriate tension (usually 100 N / m to 500 N / m) is applied to the support to reduce the fluttering of the support and to apply the coating while maintaining the flatness. It is preferable to do. Flatness is the amount of runout in the vertical direction perpendicular to the width direction and the transport direction of the support, and is ideally 0 mm but is usually 1 mm or less.

As a support, a support film is usually used. As a support film, a film which can be used as a support of an optical laminate can be appropriately selected and used. Among them, an optically anisotropic laminate comprising a support film, a retardation layer, and an optically anisotropic layer can be used as an optical film, and from the viewpoint of eliminating the need for peeling of the support film, the support film is transparent. Films are preferred. Specifically, the total light transmittance of the support film is preferably 80% or more, more preferably 85% or more, and particularly preferably 88% or more.

The material of the support film is not particularly limited, and various resins may be used. As an example of resin, resin containing the polymer demonstrated as a material of the base material which can be used for formation of an optical anisotropic layer is mentioned. Among these, from the viewpoints of transparency, low hygroscopicity, dimensional stability and lightness, as the polymer contained in the resin, an alicyclic structure-containing polymer and a cellulose ester are preferable, and an alicyclic structure-containing polymer is preferable. More preferable.

As the support, one having an orientation control force can be used. The alignment control force of the support refers to the property of the support capable of aligning the liquid crystal compound for retardation layer in the liquid crystal composition coated on the support.

The orientation control force can be applied by subjecting a member such as a film to be a material of the support to a process for applying the orientation control force. Examples of such treatment include stretching treatment and rubbing treatment.

In a preferred embodiment, the support is a stretched film. By setting it as this stretched film, it can be set as the support body which has the orientation control force according to the extending | stretching direction.

The stretching direction of the stretched film is arbitrary. Therefore, the stretching direction may be a longitudinal direction, a width direction, or an oblique direction. Furthermore, among these stretching directions, stretching may be performed in two or more directions. The stretching ratio can be appropriately set in the range in which the alignment regulating force is generated on the surface of the support. When the material of the support is a resin having a positive intrinsic birefringence value, molecules are oriented in the stretching direction and a slow axis is developed in the stretching direction. Drawing can be performed using known drawing machines, such as a tenter drawing machine.

In a further preferred embodiment, the support is a diagonally stretched film. When the support is an obliquely stretched film, an angle between the stretching direction and the width direction of the stretched film may specifically be more than 0 ° and less than 90 °. By using such an obliquely stretched film as a support, the optically anisotropic laminate can be made a material that enables efficient production of a circularly polarizing plate.

In one embodiment, the angle between the stretching direction and the width direction of the stretched film is preferably 15 ° ± 5 °, 22.5 ± 5 °, 45 ° ± 5 °, or 75 ° ± 5 °, more preferably Is 15 ° ± 4 °, 22.5 ° ± 4 °, 45 ° ± 4 °, or 75 ° ± 4 °, and even more preferably 15 ° ± 3 °, 22.5 ° ± 3 °, 45 ° ± 3 It may be a specific range such as ° or 75 ° ± 3 °. By having such an angular relationship, the optically anisotropic laminate can be made a material that enables efficient production of a circularly polarizing plate.

Examples of coating methods for liquid crystal compositions include curtain coating, extrusion coating, roll coating, spin coating, dip coating, bar coating, spray coating, slide coating, print coating, gravure coating Methods include die coating, gap coating, and dipping. The thickness of the layer of the liquid crystal composition to be coated can be appropriately set according to the desired thickness required for the liquid crystal layer as the retardation layer.

After the liquid crystal composition is coated on the support to obtain a layer of the liquid crystal composition, a step of aligning the liquid crystal compound for retardation layer contained in the layer of the liquid crystal composition is performed. Thus, the liquid crystal compound for retardation layer contained in the layer of the liquid crystal composition is aligned in the alignment direction according to the alignment regulating force of the support. For example, when a stretched film is used as a support, the liquid crystal compound for retardation layer contained in the layer of the liquid crystal composition is aligned in parallel with the stretching direction of the stretched film.

The alignment of the liquid crystal compound for retardation layer may be achieved immediately by coating, but may be achieved by applying an alignment treatment such as heating after coating, if necessary. The conditions for the alignment treatment can be set as appropriate depending on the properties of the liquid crystal composition to be used, and for example, the conditions may be such that the treatment is performed for 30 seconds to 5 minutes under a temperature condition of 50 ° C to 160 ° C.

As described above, by orienting the liquid crystal compound for retardation layer in the layer of the liquid crystal composition, desired optical properties are exhibited in the layer of the liquid crystal composition, so that a liquid crystal layer which can function as a retardation layer can be obtained.

The method for producing a liquid crystal layer as a retardation layer described above may further include an optional step. The method for producing a liquid crystal layer may include, for example, a step of drying a layer of the liquid crystal composition or the liquid crystal layer. Such drying can be achieved by a drying method such as natural drying, heat drying, reduced pressure drying, reduced pressure heat drying and the like.

Further, in the method for producing a liquid crystal layer as a retardation layer, for example, after the liquid crystal compound for retardation layer contained in the liquid crystal composition is oriented, the step of fixing the alignment state of the liquid crystal compound for retardation layer is performed. May be In this step, usually, the alignment state of the liquid crystal compound for retardation layer is fixed by polymerizing the liquid crystal compound for retardation layer. Further, by polymerizing the liquid crystal compound for retardation layer, the rigidity of the liquid crystal layer can be enhanced, and the mechanical strength can be improved.

The polymerization of the liquid crystal compound for retardation layer may be appropriately selected in accordance with the properties of the components of the liquid crystal composition. For example, a method of irradiating light is preferable. Among them, a method of irradiating ultraviolet light is preferable because the operation is simple. The irradiation conditions such as the ultraviolet irradiation intensity, the ultraviolet irradiation time, the ultraviolet integrated light quantity, and the ultraviolet irradiation light source can be adjusted in the same range as the irradiation conditions in the method for producing the optically anisotropic layer.

During polymerization, the liquid crystal compound for retardation layer is usually polymerized while maintaining the alignment of its molecules. Therefore, a liquid crystal layer containing a polymer of a liquid crystal compound for retardation layer aligned in a direction parallel to the alignment direction of the liquid crystal compound for retardation layer contained in the liquid crystal composition before polymerization can be obtained by the above polymerization. . Therefore, for example, when a stretched film is used as a support, a liquid crystal layer having an alignment direction parallel to the stretching direction of the stretched film can be obtained. Here, “parallel” means that the difference between the stretching direction of the stretched film and the alignment direction of the polymer of the liquid crystal compound for retardation layer is usually ± 3 °, preferably ± 1 °, and ideally 0 °.

In the liquid crystal layer as a retardation layer produced by the above-mentioned production method, the molecules of the polymer obtained from the liquid crystal compound for retardation layer preferably have an orientation regularity that is horizontally oriented with respect to the support film. . For example, in the case of using a support film having an alignment control force, it is possible to horizontally align the molecules of the polymer of the liquid crystal compound for retardation layer in the liquid crystal layer. Here, “horizontal alignment” of the molecules of the polymer of the liquid crystal compound for retardation layer with respect to the support film means the direction of the major axis of the mesogen skeleton of the structural unit derived from the liquid crystal compound for retardation layer contained in the polymer. The average direction is parallel to or nearly parallel to the film surface (for example, the angle between the film surface and the film is within 5 °), which means that the film is oriented in one direction. As in the case of using the compound represented by the formula (II) as the liquid crystal compound for retardation layer, in the case where plural kinds of mesogen skeletons having different alignment directions are present in the liquid crystal layer, usually, the most preferable among them. The direction in which the long axis direction of the long type mesogen skeleton is oriented is the orientation direction.

Furthermore, the method for producing a liquid crystal layer as a retardation layer may include the step of peeling the support after obtaining the liquid crystal layer.

[3.3. Optional Layer in Optically Anisotropic Laminate]
The optically anisotropic laminate may further include an optional layer in combination with the optically anisotropic layer and the retardation layer. Examples of the optional layer include an adhesive layer, a hard coat layer and the like.

[3.4. Method for producing optically anisotropic laminate]
The optically anisotropic laminate can be produced, for example, by the following production method 1 or 2.

Manufacturing method 1:
Producing a retardation layer;
A step of forming an optically anisotropic layer on a retardation layer by performing the method for producing an optically anisotropic layer described above using the retardation layer as a substrate, to obtain an optically anisotropic laminate And manufacturing methods.

When the coating liquid is applied on the retardation layer as in the production method 1, an optically anisotropic layer is formed on the retardation layer by drying the coating liquid layer, and an optically anisotropic laminate is obtained. Is obtained.

Manufacturing method 2:
Producing a retardation layer;
A process of producing a multilayer for transfer;
Bonding the optically anisotropic layer of the multilayer for transfer and the retardation layer to obtain an optically anisotropic laminate,
And exfoliating the base material of the transfer multilayer.

When manufacturing an optically anisotropic laminated body by bonding an optically anisotropic layer and a retardation layer like manufacturing method 2, an appropriate adhesive agent can be used for bonding. As this adhesive, for example, the same adhesive as used in a polarizing plate described later can be used.

Moreover, in addition to the process mentioned above, the manufacturing method of said optical anisotropic laminated body may include the arbitrary processes. For example, the manufacturing method may include the step of providing an arbitrary layer such as a hard coat layer.

[4. Polarizer〕
The polarizing plate of the present invention is provided with a linear polarizer, and the above-described optically anisotropic layer, a multilayer for transfer, or an optically anisotropic laminate. By providing such a polarizing plate in the image display device, the visibility of the image when the image display device is viewed from the tilt direction can be enhanced.

As the linear polarizer, known linear polarizers used in devices such as liquid crystal displays and other optical devices can be used. An example of a linear polarizer is a film obtained by adsorbing iodine or a dichroic dye to a polyvinyl alcohol film and then uniaxially stretching in a boric acid bath; iodine or a dichroic dye is adsorbed to a polyvinyl alcohol film And a film obtained by further stretching and further modifying a part of polyvinyl alcohol units in the molecular chain into polyvinylene units. In addition, as another example of the linear polarizer, a polarizer having a function of separating polarized light into reflected light and transmitted light, such as a grid polarizer, a multilayer polarizer, a cholesteric liquid crystal polarizer and the like can be mentioned. Among these, as the linear polarizer, a polarizer containing polyvinyl alcohol is preferable.

When natural light is incident on the linear polarizer, only one polarized light is transmitted. Although the degree of polarization of this linear polarizer is not particularly limited, it is preferably 98% or more, more preferably 99% or more.
The thickness of the linear polarizer is preferably 5 μm to 80 μm.

The polarizing plate may further include an adhesive layer for bonding the linear polarizer and the optically anisotropic layer, the transfer multilayer, or the optically anisotropic laminate. As the adhesive layer, a layer obtained by curing a curable adhesive can be used. Although a thermosetting adhesive may be used as a curable adhesive, it is preferable to use a photocurable adhesive. As the photocurable adhesive, one containing a polymer or a reactive monomer can be used. In addition, the adhesive may contain a solvent, a photopolymerization initiator, other additives, and the like as needed.

The photocurable adhesive is an adhesive that can be cured by irradiation with light such as visible light, ultraviolet light, and infrared light. Among them, an adhesive that can be cured by ultraviolet light is preferable because the operation is simple.

The thickness of the adhesive layer is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 30 μm or less, more preferably 20 μm or less, and still more preferably 10 μm or less. By setting the thickness of the adhesive layer within the above range, good adhesion can be achieved without damaging the optical properties of the optically anisotropic layer.

Moreover, when a polarizing plate is equipped with an optical anisotropic laminated body, the polarizing plate can function as a circularly-polarizing plate. Here, the term "circularly polarizing plate" includes not only a circularly polarizing plate in a narrow sense but also an elliptically polarizing plate. Such a circularly polarizing plate may be provided with a linear polarizer, an optically anisotropic layer, and a retardation layer in this order. In addition, such a circularly polarizing plate may be provided with a linear polarizer, a retardation layer and an optically anisotropic layer in this order.

In the circularly polarizing plate as described above, the angle formed by the slow axis of the retardation layer with respect to the polarization absorption axis of the linear polarizer is preferably 45 ° or near. Specifically, the above angle is preferably 45 ° ± 5 °, more preferably 45 ° ± 4 °, and particularly preferably 45 ° ± 3 °.

The above-mentioned polarizing plate may further contain any layer. As an arbitrary layer, a polarizer protective film layer is mentioned, for example. Any transparent film layer may be used as the polarizer protective film layer. Among them, a film layer of a resin excellent in transparency, mechanical strength, thermal stability, moisture shielding property and the like is preferable. As such resin, acetate resin such as triacetyl cellulose, polyester resin, polyether sulfone resin, polycarbonate resin, polycarbonate resin, polyamide resin, polyimide resin, linear olefin resin, cyclic olefin resin, (meth) acrylic resin, etc. are mentioned. Be Furthermore, as an arbitrary layer which a polarizing plate may contain, for example, a hard coat layer such as an impact resistant polymethacrylate resin layer, a mat layer which improves the slipperiness of the film, a reflection suppressing layer, an antifouling layer and the like can be mentioned. These optional layers may be provided only in one layer or in two or more layers.

The polarizing plate can be produced by bonding a linear polarizer and an optically anisotropic layer, a multilayer for transfer, or an optically anisotropic laminate, as necessary, using an adhesive.

[5. Image display device]
The image display apparatus of the present invention comprises the above-described polarizing plate of the present invention. The image display device of the present invention also usually comprises an image display element. In the image display device, the polarizing plate is usually provided on the viewing side of the image display element. At this time, the direction of the polarizing plate can be arbitrarily set according to the application of the polarizing plate. Therefore, the image display apparatus may be provided with an optically anisotropic layer, a transfer multilayer, or an optically anisotropic laminate, a polarizer, and an image display element in this order. In addition, the image display device may include a polarizer; an optically anisotropic layer, a multilayer for transfer, or an optically anisotropic laminate; and an image display element in this order.

There are various types of image display devices according to the type of image display element, but as a typical example, a liquid crystal display device provided with a liquid crystal cell as the image display element, and an organic EL element as the image display element The organic EL display apparatus provided is mentioned.
The image display apparatus of the present invention includes the optical anisotropic layer of the present invention as a component, thereby suppressing the reflection of external light and enabling light for displaying an image to be transmitted through polarized sunglasses. be able to. Furthermore, while having such an effect, the display device can have high durability and a good color tone.

Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to the embodiments shown below, and can be implemented with arbitrary modifications without departing from the scope of the claims of the present invention and the equivalents thereof. In the following description, "%" and "parts" representing amounts are by weight unless otherwise stated. Moreover, unless otherwise indicated, the operation described below was performed in a normal temperature and pressure atmosphere.

〔Evaluation method〕
[Optical properties of film]
The optical properties (retardation, retardation, and reverse wavelength dispersion characteristics) of sample layers (optically anisotropic layer, retardation layer, etc.) formed on a certain film (base film etc.) It was measured.

The sample layer to be evaluated was attached to a slide glass with an adhesive (an adhesive is “CS9621T” manufactured by Nitto Denko Corporation). Thereafter, the film was peeled off to obtain a sample provided with a slide glass and a sample layer. This sample was placed on the stage of a retardation meter (manufactured by Axometrics) to measure the wavelength dispersion of the in-plane retardation Re of the sample layer. Here, the wavelength dispersion of the in-plane retardation Re is a graph showing the in-plane retardation Re for each wavelength, for example, it is shown as a graph in the coordinates with the horizontal axis as the wavelength and the vertical axis as the in-plane retardation Re. Be From the wavelength dispersion of the in-plane retardation Re of the sample layer thus obtained, the in-plane retardation Re (450), Re (550), Re (590) and Re (wavelength) at wavelengths 450 nm, 550 nm, 590 nm and 650 nm. Asked for 650).

The wavelength dispersion of the retardation Re40 of the sample layer in the direction of inclination at an angle of 40 ° to the thickness direction of the sample layer was measured by inclining the stage by 40 ° with the slow axis of the sample layer as the rotation axis. . Here, the wavelength dispersion of the retardation Re40 is a graph representing the retardation Re40 for each wavelength, and is shown as a graph, for example, in coordinates where the horizontal axis is the wavelength and the vertical axis is the in-plane retardation Re40.

Furthermore, a refractive index nx of the sample layer in the in-plane direction giving the maximum refractive index using a prism coupler (manufactured by Metricon), the in-plane direction perpendicular to the nx direction The refractive index ny of and the refractive index nz in the thickness direction were measured at wavelengths of 407 nm, 532 nm and 633 nm, and Cauchy fitting was performed to obtain wavelength dispersions of refractive indices nx, ny and nz. Here, the wavelength dispersion of the refractive index is a graph representing the refractive index for each wavelength, and for example, it is shown as a graph at the coordinates with the horizontal axis as the wavelength and the vertical axis as the refractive index.

Thereafter, the wavelength dispersion of the retardation Rth in the thickness direction of the sample layer was calculated based on the data of the retardation Re40 and the wavelength dispersion of the refractive index. Here, the wavelength dispersion of the retardation Rth in the thickness direction is a graph showing the retardation Rth in the thickness direction for each wavelength, and for example, in the coordinate where the horizontal axis is the wavelength and the vertical axis is the retardation Rth in the thickness direction. It is shown as a graph. Then, from the wavelength dispersion of the retardation Rth in the thickness direction of the sample layer thus determined, the retardations Rth (450), Rth (550), Rth (590) in the thickness direction of the sample layer at wavelengths 450 nm, 550 nm, 590 nm and 650 nm. And Rth (650) were determined.

[Thickness]
The thickness of a sample layer (optically anisotropic layer, retardation layer, etc.) formed on a certain film (base film; It measured using the thickness measurement apparatus ("fill metrics" by the Filmetrics company).

[Haze change ratio]
A flat glass with an optical adhesive (CS9621 manufactured by Nitto Denko Corporation) was prepared. The optically anisotropic layer of the transfer multilayer was transferred to this flat glass to prepare a laminate for haze measurement. Using this haze measurement laminate, the haze of the optically anisotropic layer is measured according to JIS K 7136: 2000 using a haze meter ("Haze Guard II" manufactured by Toyo Seiki Seisakusho; the same in the following). , Got an initial haze value.
Subsequently, the haze measurement laminate was placed in an oven and heated. The heating temperature was 85 ° C., and the heating time was 100 hours. After heating, the haze was again measured with a haze meter to obtain a haze value after heating. From the initial haze value and the post-heating haze value, the haze change ratio (after-heating haze value / initial haze value) was calculated.

[Curing degree]
The optically anisotropic layer for curing degree measurement was prepared by peeling the optically anisotropic layer from the substrate.
The infrared absorption spectrum of the optically anisotropic layer in the optically anisotropic layer for curing degree measurement was measured by the ATR method. Specifically, the optical anisotropy exposed on the surface of the laminate for curing degree measurement under the condition of one reflection using ZeSe as a prism by an ATR measurement apparatus (model name “Nicolet iS 5N” manufactured by Thermo Fisher SCIENTIFIC) . measuring the infrared absorption spectrum of sexual layer infrared absorption spectrum, 1720 cm peak area of appearing in the vicinity of 810 cm ^-1 as _{.A C-H} obtained as a relationship between wave number and absorbance, and the _{a C = O} ^- The area of the peak appeared in the vicinity of ¹ was measured In the Examples and Comparative Examples, since the positive C polymer has a C _結合 O bond similar to C = O _MD , the influence of similar CCO bond is The excluded quantification was carried out (Reference Example 3) From these measurement results, the value of A _C−H / A _{C = O} (mesogen compound) was obtained.

[B ^* ]
The optically anisotropic layer of the transfer multilayer was transferred to a flat glass by the same operation as in the preparation of the haze measurement laminate to prepare a hue measurement laminate. The transmittance of the visible region (from 380 nm to 780 nm) of this laminate for color measurement was measured at intervals of 1.0 nm with a spectrophotometer (“V-550” manufactured by JASCO Corporation). The hue b ^* was calculated based on the obtained measurement results. The observation conditions at this time were a field of view of 2 °, a light source D65, and a data interval of 2 nm.

Example 1
The solvent was prepared by mixing 1,3-dioxolane (DOL) and methyl isobutyl ketone (MIBK). The mixing ratio (DOL / MIBK, weight ratio) of DOL and MIBK was 80/20.
55 parts by weight of a photopolymerizable reverse wavelength dispersion liquid crystal compound (CN point is 96 ° C.) represented by the following formula (B1), 45 parts by weight of a copolymer of diisopropyl fumarate and cinnamic acid ester as a positive C polymer 1.65 parts by weight of a polymerization initiator (trade name "Irgacure Oxe 04", manufactured by BASF AG), and a crosslinking agent (trade name "A-TMPT", trimethylolpropane triacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.) A coating liquid was prepared by dissolving 65 parts by weight in a solvent so that the solid concentration would be 12%.

The copolymer of diisopropyl fumarate and cinnamic acid ester used for preparation of the coating liquid is a polyfumaric acid having a repeating unit represented by the following formula (P1) and a repeating unit represented by the following formula (P2) It was ester (weight average molecular weight 72,000). Further, in the following formulas (P1) and (P2), R represents an isopropyl group, and the ratio of the number m of repeating units and n is 85:15.

As a base film, the unstretched film (The Zeon Corporation make, glass transition temperature (Tg) 163 degreeC of resin, 100 micrometers in thickness) which consists of resin containing an alicyclic structure containing polymer was prepared. The coating liquid was coated on the surface of the base film using a coating blade to form a coating liquid layer. The thickness of the coating liquid layer was adjusted so that the thickness of the obtained optically anisotropic layer was about 10 μm.

Thereafter, the coating liquid layer is dried in an oven at 85 ° C. for 5 minutes to evaporate the solvent in the coating liquid layer, and a multilayer having a layer structure of (dried coating liquid layer) / (base film) I got

Furthermore, ultraviolet irradiation was performed on the dried coating liquid layer. Ultraviolet irradiation is performed from the light source to the surface on the dried coating liquid layer side of the multiple layer under the conditions of an illuminance of 300 mW / cm ² and an integrated light amount of 600 mJ / cm ² using an irradiation apparatus equipped with a high pressure mercury light source. It performed by irradiating an ultraviolet-ray. The dried coating liquid layer was cured by the ultraviolet irradiation to form an optically anisotropic layer, and a transfer multilayer having a layer configuration of (optically anisotropic layer) / (base film) was obtained. . The optical properties of the obtained optical anisotropic layer of the transfer double layer were measured, and nx (A), ny (A), nz (A), Rth (A450) / Rth (A550), Rth (Rth (A)). A650) / Rth (A550), Re (A590), and Rth (A590) were determined. Furthermore, the curing degree A, b ^* and the haze change ratio of the optically anisotropic layer were measured.

[Examples 2 to 4 and Comparative Examples 1 to 4]
A transfer multilayer was obtained and evaluated in the same manner as in Example 1 except that the integrated light amount was changed to the values shown in Table 1.

The results of Examples and Comparative Examples are summarized in Tables 1 and 2.

As is clear from the results of the examples and comparative examples, the optically anisotropic layer of the examples having the specific degree of cure A specified in the present application has a small increase in haze upon heating, and thus has high durability. I understand. The optically anisotropic layer of the example is also found to have a good color tone with ab ^* value of 2.2 or less.

Reference Example 1: Confirmation of Wavelength Dispersion of Inverse-Wavelength-Dispersed Liquid Crystal Compound Represented by Formula (B1)
100 parts by weight of the photopolymerizable reverse wavelength dispersion liquid crystal compound represented by the formula (B1), 3 parts by weight of a photopolymerization initiator ("Irgacure 379 EG" manufactured by BASF Corporation), and a surfactant ("Megafuck" manufactured by DIC Corporation) F-562 ") 0.3 parts by weight is mixed, and further, a mixed solvent of cyclopentanone and 1,3-dioxolane (weight ratio cyclopentanone: 1,3-dioxolane = 4: 6) as a dilution solvent, The solid content was added to be 22% by weight, and dissolved by heating to 50 ° C. The resulting mixture was filtered through a membrane filter with a pore size of 0.45 μm to obtain a liquid crystal composition.

An unstretched film ("Zeonor film" manufactured by Nippon Zeon Co., Ltd.) made of a resin containing an alicyclic structure-containing polymer was prepared. By subjecting this unstretched film to rubbing treatment, an alignment substrate was prepared.

The liquid crystal composition was coated on the alignment substrate with a bar coater to form a layer of the liquid crystal composition. The thickness of the layer of the liquid crystal composition was adjusted so that the thickness of the optically anisotropic layer obtained after curing was about 2.3 μm.

After that, the layer of the liquid crystal composition was dried in an oven at 110 ° C. for about 4 minutes to evaporate the solvent in the liquid crystal composition and simultaneously homogeneously align the reverse wavelength dispersion liquid crystal compound contained in the liquid crystal composition.

Thereafter, the layer of the liquid crystal composition was irradiated with ultraviolet light using an ultraviolet irradiation device. This ultraviolet irradiation was performed in a nitrogen atmosphere in a state where the alignment substrate was fixed to the SUS plate with a tape. The layer of the liquid crystal composition was cured by irradiation with ultraviolet light to obtain a sample film provided with an optically anisotropic layer and an alignment substrate.

The wavelength dispersion of the in-plane retardation of this sample film was measured by a retardation meter (manufactured by Axometrics). Since the alignment substrate has no in-plane retardation, the in-plane retardation obtained by the above measurement indicates the in-plane retardation of the optically anisotropic layer. As a result of the measurement, the in-plane retardations Re (450), Re (550) and Re (650) at wavelengths 450 nm, 550 nm and 650 nm satisfied Re (450) <Re (550) <Re (650). Therefore, it was confirmed that the photopolymerizable reverse wavelength dispersive liquid crystal compound represented by the formula (B1) exhibits in-plane retardation of reverse wavelength dispersibility when it is homogeneously aligned.

Reference Example 2: Confirmation that the copolymer of diisopropyl fumarate and cinnamic acid ester is a positive C polymer
A copolymer of diisopropyl fumarate and cinnamate was added to N-methylpyrrolidone so that the solid concentration became 12% by weight, and was dissolved at room temperature to obtain a polymer solution.

An unstretched film ("Zeonor film" manufactured by Nippon Zeon Co., Ltd.) made of a resin containing an alicyclic structure-containing polymer was prepared. The polymer solution was applied onto the unstretched film using an applicator to form a layer of the polymer solution. Then, the sample film was dried in an oven at 85 ° C. for about 10 minutes, and the solvent was evaporated to obtain a sample film provided with a polymer film having a thickness of about 10 μm and an unstretched film.

This sample film was placed on the stage of a retardation meter (manufactured by Axometrics), and the in-plane retardation Re0 of the sample film was measured at a measurement wavelength of 590 nm. Since the unstretched film is an optically isotropic film, the in-plane retardation Re0 measured represents the in-plane retardation Re0 of the polymer film. As a result of the measurement, since the in-plane retardation Re0 was Re0 ≦ 1 nm, it was confirmed that nx (P) ≧ ny (P), and that these were the same or close values.

Then, the stage was inclined 40 ° with the slow axis of the polymer film as the axis of rotation of the stage, and the retardation Re40 in the inclined direction forming an angle of 40 ° with the thickness direction of the sample film was measured. And the slow axis direction of the polymer film was measured by this measurement. If the “slow axis direction” is perpendicular to the “stage rotation axis”, it can be determined that nz (P)> nx (P). Conversely, the “slow axis direction” is the “stage rotation axis” It can be determined that ny (P)> nz (P) if parallel to. As a result of the measurement, since the slow axis direction was perpendicular to the rotation axis of the stage, it can be determined that the refractive index nx (P) and nz (P) of the polymer film satisfy nz (P)> nx (P) The

Accordingly, when a copolymer of diisopropyl fumarate and cinnamate is formed into a polymer film by a coating method using a solution of this copolymer, the refractive index of the polymer film is nz (P)> It was confirmed that nx (P) ≧ ny (P) was satisfied. Therefore, it was confirmed that the copolymer of diisopropyl fumarate and cinnamate corresponds to a positive C polymer.

[Reference Example 3]
The same operation as in Example 3 was performed except that the amounts of the mesogen compound and the positive C polymer in the coating liquid were changed, to obtain a plurality of transfer multilayers. The infrared absorption spectrum of each of the optically anisotropic layers of the obtained transfer multilayer was measured by the ATR method. The area of the peak appearing in the vicinity of 1720 cm ^{-1 of the} obtained infrared absorption spectrum was determined as A _{c = O.} As a result, the results shown in Table 3 were obtained. From these values, the constant a _{C = O} (mesogen compound) was calculated by the least squares method. As a result, values of ac _{= O} (mesogen compound) = 12.93 and ac _{= O} (polymer) = 21.42 were obtained. Based on these values, the value of A _{c = O 2} (mesogen compound) in Examples and Comparative Examples was determined, and the degree of curing A was calculated.

Claims

An optically anisotropic layer comprising a positive C polymer, a mesogen compound, and a polymer of the mesogen compound,
When the film of the positive C polymer is formed by a coating method using a solution of the positive C polymer, the positive C polymer is a polymer in which the film satisfies the formula (1),
The mesogen compound is a compound having a mesogen skeleton and an acrylate structure,
The optically anisotropic layer is an optically anisotropic layer that satisfies Formula (2) and Formula (3):
nz (P)> nx (P) ≧ ny (P) Formula (1)
nz (A)> nx (A) ≧ ny (A) Formula (2)
0.073 <A C−H / A C = O (mesogenic compound) <0.125 Formula (3)
However,
nx (P), ny (P) and nz (P) are the main refractive indices of the film,
nx (A), ny (A) and nz (A) are main refractive indices of the optically anisotropic layer,
AC-H is infrared absorption concerning out-of-plane bending vibration of C—H bond of the acrylate structure of the mesogen compound in infrared absorption spectrum of the optically anisotropic layer,
A C = O (mesogen compound) is an infrared absorption of the stretching vibration of the C = O bond of the acrylate structure of the mesogen compound in the infrared absorption spectrum of the optically anisotropic layer, and the absorption of the mesogen compound It is the sum of infrared absorption applied to the stretching vibration of the C = O bond derived from the C = O bond of the acrylate structure.
The optically anisotropic layer according to claim 1, wherein the mesogen compound is a compound that exhibits reverse wavelength dispersive in-plane retardation when homogeneously oriented.
The optically anisotropic layer according to claim 1 or 2, which satisfies the formula (4) and the formula (5):
0.50 <Rth (A450) / Rth (A550) <1.00 Formula (4)
1.00 ≦ Rth (A650) / Rth (A550) <1.25 Formula (5)
However,
Rth (A450) is a retardation in the thickness direction of the optically anisotropic layer at a wavelength of 450 nm,
Rth (A550) is a retardation in the thickness direction of the optically anisotropic layer at a wavelength of 550 nm,
Rth (A650) is a retardation in the thickness direction at a wavelength of 650 nm of the optically anisotropic layer.
The optically anisotropic layer according to any one of claims 1 to 3, wherein the mesogen compound is represented by the following formula (I):

(In the above formula (I),
Y 1 to Y 8 each independently represent a single chemical bond, —O—, —S—, —O—C (= O) —, —C (= O) —O—, —O—C (= O) -O-, -NR 1 -C (= O)-, -C (= O) -NR 1- , -O-C (= O) -NR 1- , -NR 1 -C (= O) -O-, -NR 1 -C (= O) -NR 1- , -O-NR 1- , or -NR 1 -O-. Here, R 1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
G 1 and G 2 each independently represent an optionally substituted divalent aliphatic group having 1 to 20 carbon atoms. In addition, in the aliphatic group, one or more -O-, -S-, -O-C (= O)-, -C (= O) -O-, -O-C per aliphatic group. (= O) -O -, - NR 2 -C (= O) -, - C (= O) -NR 2 -, - NR 2 -, or, -C (= O) - is be interposed Good. However, it excludes the case where two or more -O- or -S- are adjacent to each other. Here, R 2 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Z 1 and Z 2 each independently represent an alkenyl group having 2 to 10 carbon atoms which may be substituted by a halogen atom.
A x represents an organic group having 2 to 30 carbon atoms which has at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring.
A y has a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, and a substituent Also a cycloalkyl group having 3 to 12 carbon atoms, an alkynyl group having 2 to 20 carbon atoms which may have a substituent, -C (= O) -R 3 , -SO 2 -R 4 , -C ( = S) NH-R 9 , or an organic group having 2 to 30 carbon atoms, having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocycle. Here, R 3 has an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, and a substituent. Or a cycloalkyl group having 3 to 12 carbon atoms or an aromatic hydrocarbon ring group having 5 to 12 carbon atoms. R 4 represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a phenyl group or a 4-methylphenyl group. R 9 is an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, carbon which may have a substituent And a cycloalkyl group of 3 to 12 or an aromatic group of 5 to 20 carbon atoms which may have a substituent. The aromatic ring which said A x and A y has may have a substituent. The A x and A y may be taken together to form a ring.
A 1 represents a trivalent aromatic group which may have a substituent.
Each of A 2 and A 3 independently represents a divalent alicyclic hydrocarbon group having 3 to 30 carbon atoms which may have a substituent.
Each of A 4 and A 5 independently represents a divalent aromatic group having 6 to 30 carbon atoms which may have a substituent.
Q 1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent.
m and n each independently represent 0 or 1;
However, one or both of Z 1 -Y 7 -and -Y 8 -Z 2 are acryloyloxy groups. )
The mesogen compound according to any one of claims 1 to 4, wherein the molecular structure contains at least one selected from the group consisting of a benzothiazole ring and a combination of a cyclohexyl ring and a phenyl ring. Optically anisotropic layer.
The optically anisotropic layer according to any one of claims 1 to 5, wherein the positive C polymer is at least one polymer selected from the group consisting of polyvinyl carbazole, polyfumaric acid ester and a cellulose derivative.
The optical anisotropy according to any one of claims 1 to 6, wherein a ratio of the mesogen compound and a polymer thereof in a total solid content of the optically anisotropic layer is 20% by weight or more and 60% by weight or less. layer.
The optically anisotropic layer according to any one of claims 1 to 7, which satisfies the formulas (6) and (7):
Re (A 590) ≦ 10 nm Formula (6)
−200 nm ≦ Rth (A 590) ≦ -10 nm Formula (7)
However,
Re (A 590) is an in-plane retardation of the optically anisotropic layer at a wavelength of 590 nm,
Rth (A 590) is a retardation in the thickness direction at a wavelength of 590 nm of the optically anisotropic layer.
A transfer multilayer comprising a substrate and the optically anisotropic layer according to any one of claims 1 to 8.
A optically anisotropic layer according to any one of claims 1 to 8 and a retardation layer,
The optically anisotropic laminate, wherein the retardation layer satisfies formula (8):
nx (B)> ny (B) ≧ nz (B) Formula (8)
However, nx (B), ny (B) and nz (B) are the main refractive indexes of the said phase difference layer.
The optically anisotropic laminate according to claim 10, wherein the retardation layer satisfies the formulas (9) and (10):
0.75 <Re (B450) / Re (B550) <1.00 Formula (9)
1.01 <Re (B650) / Re (B550) <1.25 Formula (10)
However,
Re (B450) is an in-plane retardation of the retardation layer at a wavelength of 450 nm,
Re (B550) is an in-plane retardation of the retardation layer at a wavelength of 550 nm,
Re (B650) is an in-plane retardation of the retardation layer at a wavelength of 650 nm.
The optically anisotropic laminate according to claim 11, wherein the retardation layer contains a liquid crystal compound for retardation layer represented by the following formula (II):

(In the above formula (II),
Y 1 to Y 8 each independently represent a single chemical bond, —O—, —S—, —O—C (= O) —, —C (= O) —O—, —O—C (= O) -O-, -NR 1 -C (= O)-, -C (= O) -NR 1- , -O-C (= O) -NR 1- , -NR 1 -C (= O) -O-, -NR 1 -C (= O) -NR 1- , -O-NR 1- , or -NR 1 -O-. Here, R 1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
G 1 and G 2 each independently represent an optionally substituted divalent aliphatic group having 1 to 20 carbon atoms. In addition, in the aliphatic group, one or more -O-, -S-, -O-C (= O)-, -C (= O) -O-, -O-C per aliphatic group. (= O) -O -, - NR 2 -C (= O) -, - C (= O) -NR 2 -, - NR 2 -, or, -C (= O) - is be interposed Good. However, it excludes the case where two or more -O- or -S- are adjacent to each other. Here, R 2 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Z 1 and Z 2 each independently represent an alkenyl group having 2 to 10 carbon atoms which may be substituted by a halogen atom.
A x represents an organic group having 2 to 30 carbon atoms which has at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring.
A y has a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, and a substituent Also a cycloalkyl group having 3 to 12 carbon atoms, an alkynyl group having 2 to 20 carbon atoms which may have a substituent, -C (= O) -R 3 , -SO 2 -R 4 , -C ( = S) NH-R 9 , or an organic group having 2 to 30 carbon atoms, having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocycle. Here, R 3 has an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, and a substituent. Or a cycloalkyl group having 3 to 12 carbon atoms or an aromatic hydrocarbon ring group having 5 to 12 carbon atoms. R 4 represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a phenyl group or a 4-methylphenyl group. R 9 is an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, carbon which may have a substituent And a cycloalkyl group of 3 to 12 or an aromatic group of 5 to 20 carbon atoms which may have a substituent. The aromatic ring which said A x and A y has may have a substituent. The A x and A y may be taken together to form a ring.
A 1 represents a trivalent aromatic group which may have a substituent.
Each of A 2 and A 3 independently represents a divalent alicyclic hydrocarbon group having 3 to 30 carbon atoms which may have a substituent.
Each of A 4 and A 5 independently represents a divalent aromatic group having 6 to 30 carbon atoms which may have a substituent.
Q 1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent.
m and n each independently represent 0 or 1; )
With linear polarizers,
An optically anisotropic layer according to any one of claims 1 to 8, a multilayer for transfer according to claim 9, or an optically anisotropic laminate according to any one of claims 10 to 12. A polarizing plate comprising a body.
The image display apparatus provided with the polarizing plate of Claim 13.
The optically anisotropic laminate according to any one of claims 10 to 12,
With linear polarizers,
An image display device, in this order,
The image display apparatus whose said image display element is a liquid crystal cell or an organic electroluminescent element.
A method of producing an optically anisotropic layer according to any one of claims 1 to 8, wherein
Providing a coating liquid containing a positive C polymer, a mesogen compound, a solvent, a photopolymerization initiator, and a crosslinking agent;
Applying the coating solution on a support surface to obtain a coating solution layer;
And irradiating the coating liquid layer with light to cure the coating liquid layer.
The ratio of the photopolymerization initiator to 100 parts by weight of the mesogen compound in the coating liquid is 1 part by weight to 10 parts by weight,
The method for producing an optically anisotropic layer according to claim 16, wherein the ratio of the crosslinking agent to 100 parts by weight of the mesogen compound is 1 part by weight to 10 parts by weight.
Integrated light amount of the light to be irradiated is 600mJ / cm 2 ~ 5000mJ / cm 2, The method according to claim 16 or 17.