WO2024128186A1 - Liquid crystal composition, liquid crystal cured layer, optical film, polarizing plate, and image display device - Google Patents

Abstract

The present invention addresses the problem of providing a liquid crystal composition which contains a copolymer having excellent compatibility with a liquid crystal compound, and has an excellent leveling property, a liquid crystal cured layer, an optical film, a polarizing plate, and an image display device. A liquid crystal composition of the present invention contains a copolymer, and a liquid crystal compound. The copolymer contains a repeating unit B having a polymer chain containing a repeating unit A, and contains a repeating unit C different from the repeating unit B, and satisfies a requirement 1 or a requirement 2.

Description

Liquid crystal composition, cured liquid crystal layer, optical film, polarizing plate and image display device

The present invention relates to a liquid crystal composition, a liquid crystal cured layer, an optical film, a polarizing plate, and an image display device.

Optical films such as optical compensation sheets and retardation films are used in various image display devices from the viewpoints of eliminating image coloration and widening the viewing angle.
As the optical film, a stretched birefringent film has been used, but in recent years, it has been proposed to use a liquid crystal cured layer using a liquid crystal compound instead of the stretched birefringent film.

For example, Patent Document 1 describes a fluorine atom-containing copolymer that contains a repeating unit represented by general formula (1) and has a block structure, graft structure, star structure or branched structure as a component contained in a liquid crystal composition for forming a liquid crystal cured layer ([Claim 1]).

JP 2021-172779 A

The inventors have studied liquid crystal compositions containing the copolymer and liquid crystal compound described in Patent Document 1 and other documents, and have found that there is room for improvement in the leveling properties of the liquid crystal composition and the compatibility between the copolymer and the liquid crystal compound, depending on the structure of the copolymer.

Therefore, an object of the present invention is to provide a liquid crystal composition which contains a copolymer having excellent compatibility with a liquid crystal compound and has excellent leveling properties.
Another object of the present invention is to provide a liquid crystal cured layer, an optical film, a polarizing plate and an image display device.

As a result of intensive research aimed at achieving the above object, the present inventors have discovered that by blending a specific copolymer, a liquid crystal composition containing a copolymer having excellent compatibility with a liquid crystal compound and having excellent leveling properties can be obtained, thereby completing the present invention.
That is, it has been found that the above object can be achieved by the following configuration.

[1]
A liquid crystal composition comprising a copolymer and a liquid crystal compound,
The liquid crystal composition, wherein the copolymer contains a repeating unit B having a polymer chain containing a repeating unit A, and a repeating unit C different from the repeating unit B, and satisfies Requirement 1 or Requirement 2 described below.
[2]
The liquid crystal composition according to [1], wherein the repeating unit B contains a sulfur atom.
[3]
The liquid crystal composition according to [1] or [2], wherein the weight average molecular weight of the copolymer is 8,000 to 1,000,000.
[4]
The liquid crystal composition according to any one of [1] to [3], wherein the weight average molecular weight of the monomer from which the repeating unit B is derived is 2,000 to 20,000.
[5]
The liquid crystal composition according to any one of [1] to [4], wherein the copolymer contains a repeating unit represented by any one of formulas (b1) to (b4) described below.
[6]
The liquid crystal composition according to any one of [1] to [5], wherein the content of the repeating unit B is 0.1 to 40% by mass with respect to the total mass of the repeating unit B and the repeating unit C.
[7]
The liquid crystal composition according to any one of [1] to [6], wherein the liquid crystal compound is a polymerizable liquid crystal compound.
[8]
The liquid crystal composition according to [7], wherein the polymerizable liquid crystal compound is at least one type of polymerizable liquid crystal compound selected from the group consisting of polymerizable rod-shaped liquid crystal compounds and polymerizable discotic liquid crystal compounds.
[9]
A liquid crystal cured layer obtained by fixing the alignment state of the liquid crystal composition according to any one of [1] to [8].
[10]
An optical film having the liquid crystal cured layer according to [9].
[11]
A polarizing plate comprising the optical film according to [10] and a polarizer.
[12]
An image display device comprising the optical film according to [10].

According to the present invention, it is possible to provide a liquid crystal composition which contains a copolymer having excellent compatibility with a liquid crystal compound and has excellent leveling properties.
The present invention can also provide a liquid crystal cured layer, an optical film, a polarizing plate and an image display device.

FIG. 1 is a schematic cross-sectional view showing an example of an optical film.

The present invention will be described in detail below.
The following description of the components may be based on representative embodiments of the present invention, but the present invention is not limited to such embodiments.
In this specification, a numerical range expressed using "to" means a range that includes the numerical values before and after "to" as the lower and upper limits.
In the present specification, each component may be used as a single substance corresponding to the respective component, or two or more substances may be used in combination. Here, when two or more substances are used in combination for each component, the content of the component refers to the total content of the substances used in combination, unless otherwise specified.
In addition, the bonding direction of a divalent group (e.g., -O-CO-) represented in this specification is not particularly limited. For example, when ^L2 is -O-CO- in the bond of " ^L1 - ^L2 - ^L3 ", when the position bonded to ^L1 side is *1 and the position bonded to ^L3 side is *2, ^L2 may be *1-O-CO-*2 or *1-CO-O-*2.

The compounds described herein may contain isomers unless otherwise specified. The isomers may be structural isomers, geometric isomers, and optical isomers.
Furthermore, when only a specific isomer of a compound is shown, this indicates that the specific isomer is preferred among the possible isomers of the compound.

In this specification, Re(λ) and Rth(λ) respectively represent the in-plane retardation and the retardation in the thickness direction at a wavelength λ, which is 550 nm unless otherwise specified.
In this specification, Re(λ) and Rth(λ) are values measured at a wavelength of λ using an AxoScan OPMF-1 (manufactured by Optosciences, Inc.).
Specifically, by inputting the average refractive index ((nx+ny+nz)/3) and the film thickness (d (μm)) into the AxoScan OPMF-1,
Slow axis direction (°)
Re(λ)=R0(λ)
Rth(λ)=((nx+ny)/2−nz)×d
is calculated.
It should be noted that R0(λ) is displayed as a numerical value calculated by AxoScan OPMF-1, and means Re(λ).

[Liquid Crystal Composition]
The liquid crystal composition of the present invention contains a copolymer and a liquid crystal compound.
The above-mentioned copolymer (hereinafter also referred to as "specific copolymer") contained in the liquid crystal composition of the present invention contains a repeating unit B having a polymer chain (hereinafter also referred to as "polymer chain A") containing a repeating unit A, and a repeating unit C different from the repeating unit B, and satisfies requirement 1 or requirement 2.
Requirement 1: The repeating unit A is a repeating unit represented by any one of the formulae (b1), (b2) and (b5) described below, and the repeating unit C is a repeating unit represented by the formula (1) described below.
Requirement 2: The repeating unit A is a repeating unit represented by the formula (1) described later, and the repeating unit C is a repeating unit represented by any one of the formulae (b1) to (b5) described later.

As described above, in the present invention, by blending the specific copolymer, it is possible to provide a liquid crystal composition having excellent compatibility with liquid crystal compounds and excellent leveling properties.
Although the details of the reason for this are not yet clear, the present inventors speculate that it is due to the following reasons.
In other words, since the specific copolymer contains a specific repeating unit B having a polymer chain containing a repeating unit A, and a specific repeating unit C, it is believed that in the liquid crystal composition, the compatibility with the liquid crystal compound is good due to the structural characteristics of these repeating units, and the leveling property is also excellent.
Each component of the liquid crystal composition of the present invention will be described in detail below.

[Specific Copolymer]
The specific polymer contained in the liquid crystal composition of the present invention is, as described above, a copolymer that contains a repeating unit B having a polymer chain (polymer chain A) containing a repeating unit A and a repeating unit C different from the repeating unit B, and that satisfies requirement 1 or requirement 2.

<Repeating Unit B>
The repeating unit B contained in the specific copolymer is a repeating unit having a polymer chain containing the repeating unit A (polymer chain A).
The polymer chain A is preferably a so-called graft chain. In other words, the repeating unit B is preferably a repeating unit having a graft chain containing the repeating unit A.

In the present invention, from the viewpoint of ease of synthesis, it is preferable that repeating unit B contains a sulfur atom.

The repeating unit B is preferably a repeating unit represented by formula (B1).

In formula (B1), R ⁴¹ and R ⁴² each independently represent a hydrogen atom or an alkyl group.
R ⁴³ represents a hydrogen atom or a substituent.
L ²¹ represents —O— or —NR ^Z21 —, where R ^Z21 represents a hydrogen atom or a substituent.
^L22 represents a single bond or a divalent linking group.
A represents a repeating unit A.

R ⁴¹ and R ⁴² are the same as R ¹¹ and R ¹² in formula (1) described later, and preferred embodiments are also the same.
R ⁴³ has the same definition as R ¹³ in formula (1) described later, and preferred embodiments are also the same.
^L21 has the same definition as ^L11 in formula (1) described later, and preferred embodiments are also the same.
The repeating unit A represented by A is as described below.

Examples of the divalent linking group represented by one embodiment of L ²² include -O-, -S-, -C(=O)-, -NR ^N -, -CH=CH-, -C≡C-, a divalent cyclic group, an alkylene group AL which may have a hydroxyl group, and a divalent linking group formed by combining these. R ^N represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.
Among these, L ²² is preferably a divalent linking group containing an -alkylene group AL-NH-COO- or a divalent linking group containing an -alkylene group AL-COO-, and more preferably an -alkylene group AL-NH-COO-alkylene group -S- or an -alkylene group AL-COO-alkylene group AL-S-.

The weight average molecular weight of the monomer from which the repeating unit B is derived is preferably from 1,000 to 50,000, more preferably from 2,000 to 20,000, and even more preferably from 4,000 to 10,000.
The weight average molecular weight of the monomer from which the repeating unit B is derived can be measured, for example, by the same method as that for the weight average molecular weight of the specific copolymer described below.
The monomer from which the repeating unit is derived refers to a monomer that can form the repeating unit by polymerizing the monomer. For example, an example of the monomer from which the repeating unit B is derived is a monomer having a polymer chain A (so-called a macromonomer).

The content of the repeating unit A in the specific copolymer is preferably from 50 to 99.99% by mass, more preferably from 60 to 99% by mass, and even more preferably from 70 to 95% by mass, based on the total mass of the repeating unit B.
The content of the repeating unit B in the specific copolymer is preferably from 0.1 to 60% by mass, more preferably from 0.1 to 40% by mass, and even more preferably from 10 to 30% by mass, based on the total mass of the repeating unit B and the repeating unit C.

<Repeating Unit C>
The repeating unit C of the specific copolymer is different from the repeating unit B, and is a repeating unit represented by formula (1) described below when the specific copolymer satisfies requirement 1, and is a repeating unit represented by any of formulas (b1) to (b5) described below when the specific copolymer satisfies requirement 2.
The content of the repeating unit C in the specific copolymer is preferably 40 to 99.9 mass %, more preferably 60 to 99.9 mass %, and even more preferably 70 to 90 mass %, based on the total mass of the repeating unit B and the repeating unit C.

<Requirements 1 and 2>
The specific copolymer satisfies requirement 1 or requirement 2.
Requirement 1: The repeating unit A is a repeating unit represented by any one of the formulae (b1), (b2) and (b5) described below, and the repeating unit C is a repeating unit represented by the formula (1) described below.
Requirement 2: The repeating unit A is a repeating unit represented by the formula (1) described later, and the repeating unit C is a repeating unit represented by any one of the formulae (b1) to (b5) described later.

From the viewpoint of compatibility with the liquid crystal compound, the specific copolymer preferably satisfies requirement 1-1 or requirement 2-1.
Requirement 1-1: The repeating unit A is a repeating unit represented by either formula (b1) or (b2) described below, and the repeating unit C is a repeating unit represented by formula (1) described below.
Requirement 2-1: The repeating unit A is a repeating unit represented by the formula (1) described later, and the repeating unit C is a repeating unit represented by any one of the formulae (b1) to (b4) described later.
The specific polymer also preferably contains a repeating unit represented by any one of formulas (b1) to (b4).

Each repeating unit is described in detail below.

In the above formula (1),
R ¹¹ and R ¹² each independently represent a hydrogen atom or an alkyl group.
R ¹³ represents a hydrogen atom or a substituent.
L ¹¹ represents —O— or —NR ^Z11 —, where R ^Z11 represents a hydrogen atom or a substituent.
L ¹² represents a single bond or a divalent linking group.
Rh represents a substituent X. The substituent X is a substituent containing two or more groups represented by the following formula (2) (hereinafter also abbreviated as "substituent SI"), or a branched hydrocarbon group having 10 or more carbon atoms containing two or more carbon atoms selected from tertiary carbon atoms and quaternary carbon atoms (hereinafter also abbreviated as "substituent LQ"). In other words, Rh represents the substituent SI or the substituent LQ.

Examples of the alkyl group represented by one embodiment of R ¹¹ and R ¹² include linear alkyl groups having 1 to 18 carbon atoms, and branched or cyclic alkyl groups having 3 to 18 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group (n-butyl group, sec-butyl group, iso-butyl group, and tert-butyl group), and a cyclohexyl group. R ¹¹ and R ¹² are preferably hydrogen atoms.
Examples of the substituent represented by R ¹³ include, for example, a hydroxyl group, an alkyl group, an alkenyl group, and an aryl group. Examples of the substituent represented by R ¹³ include, for example, -L ^R -hydroxyl group, -L ^R -alkyl group, -L ^R -alkenyl group, and -L ^R -aryl group. ^{L R} represents a divalent linking group. Examples of the divalent linking group represented by L ^R include, for example, -O-, -S-, -C(=O)-, -NR ^N -, -CH=CH-, -C≡C-, a divalent cyclic group, an alkylene group, and a divalent linking group selected from the group consisting of combinations thereof. R ^N represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms. As a group exemplified as the -L ^R -above-mentioned substituent, -CH ₂ -COO-alkylene group-hydroxyl group is preferable.
The alkyl group represented by one embodiment of R ¹³ is preferably a linear alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group.
R ¹³ is preferably a hydrogen atom or a methyl group.

With respect to -NR ^Z11 - which is one embodiment of L ¹¹ , the substituent which is one embodiment of R ^Z11 is preferably an alkyl group, more preferably a linear alkyl group having 1 to 4 carbon atoms, and further preferably a methyl group or an ethyl group. L ¹¹ is preferably -O- or -NH-, and more preferably -O-.

Examples of the divalent linking group represented by one embodiment of L ¹² include a hydrocarbon group having 1 to 20 carbon atoms, preferably an alkylene group having 1 to 20 carbon atoms, and more preferably a linear alkylene group having 1 to 18 carbon atoms, a branched alkylene group having 3 to 18 carbon atoms, or a cyclic alkylene group having 3 to 20 carbon atoms.
L ¹² is preferably a single bond or a linear alkylene group having 1 to 18 carbon atoms, and more preferably a single bond, a methylene group, an ethylene group or a propylene group.

As Rh, the substituent SI is preferable from the viewpoint of providing a liquid crystal composition with better leveling properties.
The substituent SI represented by one embodiment of Rh is not particularly limited as long as it is a substituent containing two or more groups represented by formula (2).

In the above formula (2), * represents a bonding position.
R ³¹ , R ³² and R ³³ each independently represent an alkyl group, an alkenyl group, an aryl group or an alkylenearyl group.
In a substituent containing two or more groups represented by formula (2), a plurality of R ³¹ , R ³² and R ³³ may be the same or different.
Examples of the alkyl group include linear alkyl groups having 1 to 18 carbon atoms, branched alkyl groups having 3 to 18 carbon atoms, and cyclic alkyl groups.
The alkenyl group includes, for example, alkenyl groups having 2 to 12 carbon atoms.
Examples of the aryl group include aryl groups having 6 to 12 carbon atoms. Specific examples include a phenyl group, an α-methylphenyl group, and a naphthyl group.
The alkylenearyl group may, for example, be an alkylenearyl group having 7 to 30 carbon atoms.

In the present invention, the number of groups represented by formula (2) possessed by the substituent SI is 2 or more, and from the viewpoint of reducing the surface tension of the liquid crystal composition and suppressing unevenness when forming the liquid crystal cured layer, 3 or more is preferable, 3 to 6 is more preferable, and 3 to 5 is even more preferable.

In addition, in the present invention, from the viewpoint of reducing the surface tension of the liquid crystal composition and suppressing unevenness when forming a liquid crystal cured layer, it is preferable that R ³¹ , R ³² and R ³³ in the above formula (2) are all alkyl groups, and more preferably linear alkyl groups having 1 to 18 carbon atoms.

As the substituent SI, a group represented by formula (S1) is preferred, and a group represented by formula (S2) is more preferred.

In the above formula (S1), * represents a bonding position.
R ³¹ , R ³² and R ³³ each independently represent an alkyl group, an alkenyl group, an aryl group or an alkylenearyl group.
A plurality of R ³¹ may be the same or different from each other, a plurality of R ³² may be the same or different from each other, and a plurality of R ³³ may be the same or different from each other.
n represents an integer of 2 or more.
L ^S1 represents an (n+1)-valent linking group.

R ³¹ , R ³² and R ³³ are the same as those explained in the above formula (2).

n is preferably an integer of 3 or more, more preferably an integer of 3 to 6, and even more preferably an integer of 3 to 5.

Suitable examples of the (n+1) valent linking group represented by L ^S1 include (n+1) valent hydrocarbon groups having 1 to 15 carbon atoms which may have a substituent, in which some of the carbon atoms constituting the hydrocarbon group may be substituted with heteroatoms.
Here, the substituent that the hydrocarbon group may have is preferably an alkyl group, more preferably a linear alkyl group having 1 to 4 carbon atoms, and further preferably a methyl group or an ethyl group.
Examples of the heteroatom include a silicon atom, an oxygen atom, and a nitrogen atom.

In the above formula (S2), * represents a bonding position.
R ³¹ , R ³² and R ³³ each independently represent an alkyl group, an alkenyl group, an aryl group or an alkylenearyl group.
R ³⁴ represents an alkyl group, an alkenyl group, an aryl group, or an alkylenearyl group. R ³⁴ has the same definition as R ³¹ , R ³² , and R ³³ , and preferred embodiments thereof are also the same.
A plurality of R ³¹ may be the same or different from each other, a plurality of R ³² may be the same or different from each other, and a plurality of R ³³ may be the same or different from each other.
Furthermore, m1 represents 2 or 3. m2 represents 0 or 1. m1+m2 is 3.

R ³¹ , R ³² and R ³³ are the same as those explained in the above formula (2).

The substituent LQ represented by one embodiment of Rh is not particularly limited as long as it contains two or more carbon atoms selected from a tertiary carbon atom and a quaternary carbon atom and is a branched hydrocarbon group having 10 or more carbon atoms.
The total number of tertiary carbon atoms and quaternary carbon atoms in the substituent LQ is 2 or more, preferably 3 or more, and more preferably 3 to 5.
The branched hydrocarbon group constituting the substituent LQ has 10 or more carbon atoms, preferably 10 to 30, and more preferably 10 to 20. Moreover, the hydrocarbon group is preferably an alkyl group.

In the present invention, from the viewpoint of forming a liquid crystal cured layer in which the occurrence of unevenness is further suppressed, the substituent LQ is preferably a group represented by any one of formulas (L-1) to (L-3), and more preferably a group represented by formula (L-1).

In the above formulas (L-1) to (L-3), * represents a bonding position.
The total number of tertiary carbon atoms and quaternary carbon atoms in each of the above formulas (L-1) to (L-3) is 5 groups represented by the above formula (L-1), 3 groups represented by the above formula (L-2), and 2 groups represented by the above formula (L-3).

Examples of repeating unit A include the following repeating units. In the examples described below, the repeating unit represented by the following formula K-1 will be referred to as "K-1". The same applies to other repeating units.

The repeating units represented by any of formulas (b1) to (b5) are described in detail below.

In the above formulas (b1) to (b5),
R ²¹ , R ²² , R ²⁴ and R ²⁵ each independently represent a hydrogen atom or an alkyl group.
R ²³ and R ²⁶ each independently represent a hydrogen atom or a substituent.
L ¹ and L ² each independently represent -O- or -NR ^Z1 -, where R ^Z1 represents a hydrogen atom or a substituent.
^L3 represents a single bond or a divalent linking group.
SP ¹ and SP ² each independently represent a spacer group.
^SP3 represents a single bond or a divalent linking group.
^Ph1 represents a ring structure containing two or more monocyclic aromatic rings.
^M1 represents a mesogenic group.
^T1 represents a terminal group other than the X substituent.
D represents an m-valent mesogenic group derived from a discotic liquid crystal compound.
m represents an integer of 3 to 8, and each of R ²¹ , R ²² , R ²³ , L ¹ and SP ³ in formula (b4) may be the same or different.
Rp represents a polyoxyalkylene group.
Rq represents a substituent other than the substituent X, or a hydrogen atom.

In the above formulas (b1) to (b5), the alkyl group represented by one embodiment of R ²¹ , R ²² , R ²⁴ and R ²⁵ has the same definition as the alkyl group represented by one embodiment of R ¹¹ and R ¹² in the above formula (1), and preferred embodiments are also the same.
The substituent represented by one embodiment of R ²³ and R ²⁶ has the same definition as the substituent represented by R ¹³ in the above formula (1), and the preferred embodiments are also the same.
^L1 and ^L2 are defined the same as ^L11 in the above formula (1), and preferred embodiments are also the same.
An example of the substituent represented by ^L3 is the divalent linking group represented by an example of ^SP3 .
^L3 is preferably a single bond.

The spacer group represented by SP ¹ and SP ² is not particularly limited as long as it is a divalent linking group not containing a ring structure, and specific examples thereof include divalent aliphatic hydrocarbon groups having 1 to 20 carbon atoms.
Here, the divalent aliphatic hydrocarbon group having 1 to 20 carbon atoms is, for example, preferably an alkylene group having 1 to 15 carbon atoms, and more preferably an alkylene group having 1 to 8 carbon atoms. Specific examples include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a methylhexylene group, and a heptylene group.
In the spacer group, one or two or more non-adjacent -CH ₂ - groups among those constituting a part of the divalent _hydrocarbon group may each be independently substituted with -O-, -S-, -NH-, or -N(Q)-. The substituent represented by Q is preferably an alkyl group, more preferably a linear alkyl group having 1 to 4 carbon atoms, and further preferably a methyl group or an ethyl group.
In the present invention, the spacer group is preferably a group represented by *-(CH ₂ -CH ₂ O) _n1 -*, where n1 represents an integer of 2 to 4, and * represents the bonding position with L ¹ or Ph ¹ (M ¹ ).

In the above formula (b4), examples of the divalent linking group represented by one embodiment of ^SP3 include divalent linking groups selected from the group consisting of -O-, -S-, -C(=O)-, ^-NR6- , -CH=CH-, -C≡C-, a divalent cyclic group, an alkylene group, and combinations thereof, where ^R6 represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.
Among these, a divalent linking group selected from the group consisting of -O-, -C(=O)-, a divalent cyclic group having 5 to 8 atoms, an alkylene group having 1 to 12 carbon atoms, and a combination thereof is preferred. Specific examples include -O-CO-(divalent cyclic group having 5 to 8 atoms)-O-(alkylene group having 1 to 12 carbon atoms)-, -(divalent cyclic group having 5 to 8 atoms)-(divalent cyclic group having 5 to 8 atoms)-(alkylene group having 1 to 12 carbon atoms)-CO-O-(alkylene group having 1 to 12 carbon atoms)-, and the like.

In the above formula (b1), examples of the ring structure containing two or more monocyclic aromatic rings represented by Ph ¹ include a naphthyl group and a biphenyl group, each of which may have a substituent, with a naphthyl group being preferred. As the substituent, an alkyl group is preferred, a linear alkyl group having 1 to 4 carbon atoms is more preferred, and a methyl group or an ethyl group is even more preferred.

In the above formulas (b2) and (b3), the mesogenic group represented by ^M1 is a group that represents the main skeleton of the liquid crystal molecule that contributes to the formation of liquid crystals. The liquid crystal molecules exhibit liquid crystallinity, which is an intermediate state (mesophase) between a crystalline state and an isotropic liquid state.
For the mesogenic group, reference can be made to, for example, "Flussige Kristalle in Tablellen II" (VEB Deutsche Verlag fur Grundstoff Industrie, Leipzig, published in 1984), particularly the description on pages 7 to 16, and to "Liquid Crystal Handbook" edited by the Liquid Crystal Handbook Editorial Committee (Maruzen, published in 2000), particularly the description in Chapter 3.
As the mesogenic group, for example, a group having at least one cyclic structure selected from the group consisting of an aromatic hydrocarbon group, a heterocyclic group, and an alicyclic group is preferable.
The mesogen group is preferably a group having an aromatic hydrocarbon group or a group having an alicyclic group, which may have a substituent, more preferably a group having 2 to 4 aromatic hydrocarbon groups, and even more preferably a group having 3 aromatic hydrocarbon groups, for the reason that the degree of orientation of the liquid crystal cured layer is improved. The substituent is preferably an alkyl group, an alkoxy group, an alkyl ester group, or an acetyl group, and more preferably a methyl group, a tert-butyl group, a methoxy group, or a methyl ester group.

Moreover, ^M1 in the above formulas (b2) and (b3) preferably represents a mesogen group represented by the following formula (M1-A) for the reason that repelling is further suppressed during the formation of a cured liquid crystal layer.

In the above formula (M1-A), * represents the bonding position with ^SP1 or ^T1 .
Furthermore, n represents an integer of 1 or more, and is preferably an integer of 1 to 10.
Ph ¹¹ and Ph ¹² each independently represent a divalent aromatic ring group which may have a substituent, provided that when n represents an integer of 2 or more, multiple Ph ¹¹ may be the same or different.
Furthermore, L ¹¹ represents a single bond or a divalent linking group, provided that when n represents an integer of 2 or greater, a plurality of L ¹¹ may be the same or different.
When n is an integer of 2 or more and Ph ¹¹ represents a phenylene group, in order to improve the alignment when the liquid crystal compound is aligned horizontally, it is preferable that any one of the two or more Ph ^11s is a meta-position linkage or an ortho-position linkage, and in order to improve the alignment and repelling, it is more preferable that the linkage is a meta-position linkage. On the other hand, in order to vertically align the liquid crystal compound, it is preferable that any one of the two or more Ph ^11s is a para-position linkage.

The divalent aromatic ring group represented by Ph ¹¹ and Ph ¹² includes a group in which two hydrogen atoms have been removed from an aromatic hydrocarbon ring, and a group in which two hydrogen atoms have been removed from an aromatic heterocycle. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthroline ring. Examples of the aromatic heterocycle include a furan ring, a pyrrole ring, a thiophene ring, a pyridine ring, a thiazole ring, and a benzothiazole ring. Among these, a group in which two hydrogen atoms have been removed from a benzene ring (e.g., a 1,4-phenyl group, etc.) is preferred.
In addition, the substituent that the divalent aromatic ring group may have is preferably an alkyl ester group, an alkyl group, or an acetyl group, more preferably a methyl ester group or a linear alkyl group having 1 to 4 carbon atoms, and further preferably a methyl group or an ethyl group.

Examples of the divalent linking group represented by one embodiment of L ¹¹ include -CO-, -O-, -S-, -C(=S)-, -CR ¹ R ² -, -CR ³ =CR ⁴ -, -NR ⁵ -, and combinations of two or more thereof. R ¹ to R ⁵ each independently represent a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 12 carbon atoms.

In the above formula (b2), the terminal group represented by ^T1 is a group other than the substituent X, and represents a hydrogen atom or a group present on the side chain terminal side of the mesogen group. Examples of the group present on the side chain terminal side of the mesogen group include a halogen atom, a cyano group, a nitro group, a hydroxy group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an alkoxycarbonyloxy group having 1 to 10 carbon atoms, an alkoxycarbonyl group having 1 to 10 carbon atoms (ROC(O)-: R is an alkyl group), an acyloxy group having 1 to 10 carbon atoms, an acylamino group having 1 to 10 carbon atoms, an alkoxycarbonylamino group having 1 to 10 carbon atoms, a sulfonylamino group having 1 to 10 carbon atoms, a sulfamoyl group having 1 to 10 carbon atoms, a carbamoyl group having 1 to 10 carbon atoms, a sulfinyl group having 1 to 10 carbon atoms, and a ureido group having 1 to 10 carbon atoms. Here, among the -CH ₂ - constituting a part of the alkyl group, one or two or more non-adjacent -CH ₂ - may each be independently substituted with -O-, -S-, -NH- or -N(Q)-. The substituent represented by Q is preferably an alkyl group having 1 to 4 carbon atoms.

In the above formula (b4), the m-valent mesogenic group represented by D and derived from a discotic liquid crystal compound is preferably a structure represented by the following formula (I) or any of the formulae (D2) to (D13) described below.

In formula (I), L ^D1 , L ^D2 and L ^D3 each independently represent a single bond or a divalent linking group, and H ¹ , H ² and H ³ each independently represent the following formula (IA).

In formula (IA), YA ¹ and YA ² each independently represent a methine group which may have a substituent or a nitrogen atom.
XA represents an oxygen atom, a sulfur atom, methylene or imino.
* indicates the position at which the group is bonded to the L ^D1 to L ^D3 sides in the above formula (I).
** represents the position at which the group is bonded to the * side in formula (I) above.

Preferred examples of the substituent that the methine represented by one embodiment of ^YA1 and ^YA2 may have include an alkyl group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, an alkoxycarbonylamino group, an alkylthio group, an arylthio group, a halogen atom, and a cyano group.

The divalent linking group represented by one embodiment of L ^D1 , L ^D2 and L ^D3 is preferably a divalent linking group selected from the group consisting of -O-, -S-, -C(═O)-, -NR ⁷ -, -CH═CH-, -C≡C-, a divalent cyclic group and a combination thereof, where R ⁷ represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.

The divalent cyclic group in L ^D1 , L ^D2 and L ^D3 is a divalent linking group having at least one type of cyclic structure (hereinafter, also referred to as "cyclic group"). The cyclic group is preferably a 5-membered ring, a 6-membered ring or a 7-membered ring, more preferably a 5-membered ring or a 6-membered ring, and even more preferably a 6-membered ring. The ring contained in the cyclic group may be a condensed ring. However, a monocyclic ring is more preferable than a condensed ring. In addition, the ring contained in the cyclic group may be any of an aromatic ring, an aliphatic ring and a heterocyclic ring. Preferred examples of the aromatic ring include a benzene ring and a naphthalene ring. Preferred examples of the aliphatic ring include a cyclohexane ring. Preferred examples of the heterocyclic ring include a ring containing at least one sulfur atom, a nitrogen atom or an oxygen atom, and preferred examples of the pyridine ring, a pyrimidine ring and an oxadiazole ring. More preferred cyclic groups are aromatic rings and heterocyclic rings. It is more preferred that the divalent cyclic group in the present invention is a divalent linking group consisting of only a cyclic structure (including a substituent).

Of the divalent cyclic groups in L ^D1 , L ^D2 and L ^D3 , the cyclic group having a benzene ring is preferably a 1,4-phenylene group. The cyclic group having a naphthalene ring is preferably a naphthalene-1,5-diyl group or a naphthalene-2,6-diyl group. The cyclic group having a cyclohexane ring is preferably a 1,4-cyclohexylene group. The cyclic group having a pyridine ring is preferably a pyridine-2,5-diyl group. The cyclic group having a pyrimidine ring is preferably a pyrimidine-2,5-diyl group. The cyclic group having an oxadiazole ring is preferably a 1,2,4-oxadiazole-3,5-diyl group.

The divalent cyclic group in L ^D1 , L ^D2 and L ^D3 may have a substituent. Examples of the substituent include a halogen atom (preferably a fluorine atom or a chlorine atom), a cyano group, a nitro group, an alkyl group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, an alkynyl group having 2 to 16 carbon atoms, a halogen-substituted alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, an acyl group having 2 to 16 carbon atoms, an alkylthio group having 1 to 16 carbon atoms, an acyloxy group having 2 to 16 carbon atoms, an alkoxycarbonyl group having 2 to 16 carbon atoms, a carbamoyl group, a carbamoyl group substituted with an alkyl group having 2 to 16 carbon atoms, and an acylamino group having 2 to 16 carbon atoms.

L ^D1 , L ^D2 and L ^D3 are preferably a single bond, *-O-C(=O)-, *-C(=O)-O-, *-CH=CH-, *-C≡C-, *-divalent cyclic group-, *-O-C(=O)-divalent cyclic group-, *-C(=O)-O-divalent cyclic group-, *-CH=CH-divalent cyclic group-, *-C≡C-divalent cyclic group-, *-divalent cyclic group-O-C(=O)-, *-divalent cyclic group-C(=O)-O-, *-divalent cyclic group-CH=CH- or *-divalent cyclic group-C≡C-. In particular, a single bond, *-CH=CH-, *-C≡C-, *-CH=CH-divalent cyclic group-, or *-C≡C-divalent cyclic group- is more preferable, and a single bond is even more preferable. Here, * represents the position of bonding to the 6-membered ring side in formula (I).

Examples of the compound represented by formula (I) include the exemplary compounds described in paragraphs [0068] to [0077] of JP-A No. 2010-244038 and the exemplary compounds described in paragraphs [0040] to [0063] of JP-A No. 2007-2220. The exemplary compounds can be synthesized by various methods, for example, by the methods described in paragraphs [0064] to [0070] of JP-A No. 2007-2220.

Examples of mesogenic groups (D) derived from discotic liquid crystal compounds are shown below. Note that formula (D1) corresponds to a specific example of formula (I).

In the above formula (b5), the polyoxyalkylene group represented by Rp is a group having an oxyalkylene group as a repeating unit. The polyoxyalkylene group is preferably a group represented by formula (E).

-(A-O) _p- (E)

In the above formula (E),
A represents an alkylene group.
p represents a number of 2 or more.

The number of carbon atoms in the alkylene group represented by A is not particularly limited, but is preferably 1 to 4, and more preferably 2 or 3. For example, when A is an alkylene group having 1 carbon atom, -(A-O)- represents an oxymethylene group (-CH ₂ O-), and when A is an alkylene group having 2 carbon atoms, -(A-O)- represents an oxyethylene group (-CH ₂ CH ₂ O-). The alkylene group may be either linear or branched.

The number represented by p is preferably from 2 to 1,000, and more preferably from 4 to 25.
The alkylene groups in the multiple oxyalkylene groups may be the same or different. For example, the oxyalkylene group may be an oxyalkylene group formed by linking an oxymethylene group and an oxypropylene group in -(A-O) _p -. The bonding order of each repeating unit may be either random or block.

In the above formula (b5), the substituent other than the substituent X represented by one embodiment of Rq is not particularly limited as long as it is a substituent other than the above-mentioned substituent X. Examples of the substituent other than the substituent X represented by one embodiment of Rq include an alkyl group, a phosphonic acid group, an aryl group, and a group combining these.
Examples of the aryl group represented by one embodiment of Rq include an aryl group having 6 to 20 carbon atoms. Specific examples include a phenyl group, a nonylphenyl group, and a naphthyl group.
Rq is preferably a hydrogen atom.

Examples of the repeating units represented by formulas (b1) to (b5) include the repeating units:

In the formulas H-1 to H-17 below, n and m each independently represent a number of 1 or more. However, n+m is a number of 2 or more, and if m is not present in the formulas below, n represents a number of 2 or more.

<Other repeating units>
The specific copolymer may contain repeating units other than the repeating unit B and repeating unit C described above.

<Content>
The content of the specific copolymer is preferably 0.01 to 10 mass %, more preferably 0.02 to 1 mass %, and even more preferably 0.04 to 0.5 mass %, relative to the total solid content (100 mass %) of the liquid crystal composition, from the viewpoint of obtaining superior effects of the present invention.

<Molecular weight>
The weight average molecular weight (Mw) of the specific copolymer is preferably from 2,000 to 1,000,000, and from the viewpoint of superior leveling properties of the liquid crystal composition, more preferably from 8,000 to 1,000,000, and further preferably from 8,000 to 300,000.
Here, the weight average molecular weight in the present invention is a value measured by gel permeation chromatography (GPC).
Solvent (eluent): Tetrahydrofuran (THF)
- Device name: EcoSEC HLC-8320GPC (manufactured by Tosoh Corporation)
Column: Three columns of TSKgel SuperHZM-H, TSKgel SuperHZ4000, and TSKgel SuperHZ200 (all manufactured by Tosoh Corporation) were connected and used. Column temperature: 40°C
Sample concentration: 0.1% by mass
Flow rate: 0.35 mL / min
Calibration curve: TOSOH TSK standard polystyrene calibration curves using six samples with Mw = 706,000 to 1,013 (Mw/Mn = 1.03 to 1.06)

[Liquid Crystal Compounds]
The liquid crystal compound contained in the liquid crystal composition of the present invention is not particularly limited.
The type of liquid crystal compound contained in the liquid crystal composition is not particularly limited.
Generally, liquid crystal compounds can be classified into rod-shaped and disk-shaped types based on their shape. Each type can be further divided into low molecular weight and high molecular weight types. High molecular weight compounds generally have a degree of polymerization of 100 or more (Polymer Physics: Phase Transition Dynamics, Masao Doi, p. 2, Iwanami Shoten, 1992).

In the present invention, any liquid crystal compound can be used, but it is preferable to use a rod-shaped liquid crystal compound or a discotic liquid crystal compound (discotic liquid crystal compound). Two or more rod-shaped liquid crystal compounds, two or more discotic liquid crystal compounds, or a mixture of rod-shaped and discotic liquid crystal compounds may also be used.

The liquid crystal compound is preferably a polymerizable liquid crystal compound having a polymerizable group.
The polymerizable liquid crystal compound is preferably at least one type of polymerizable liquid crystal compound selected from the group consisting of polymerizable rod-like liquid crystal compounds and polymerizable discotic liquid crystal compounds.
Examples of the polymerizable group include an acryloyl group, a methacryloyl group, an epoxy group, and a vinyl group.
The alignment of the liquid crystal compound can be fixed by polymerizing such a liquid crystal compound having a polymerizable group. After the liquid crystal compound is fixed by polymerization, it is not necessary for the liquid crystal compound to exhibit liquid crystallinity.

As the rod-shaped liquid crystal compound, those described in claim 1 of JP-A-11-513019 or paragraphs [0026] to [0098] of JP-A-2005-289980 are preferred.
As the discotic liquid crystal compound, those described in paragraphs [0020] to [0067] of JP-A No. 2007-108732 or paragraphs [0013] to [0108] of JP-A No. 2010-244038 are preferred.
Furthermore, as the liquid crystal compound, a liquid crystal compound having reverse wavelength dispersion may be used.

The content of the liquid crystal compound is preferably from 10 to 99% by mass, and more preferably from 50 to 95% by mass, based on the total solid content (100% by mass) of the liquid crystal composition.
The liquid crystal compound may be used alone or in combination of two or more. When two or more liquid crystal compounds are used in combination, the total content is preferably within the above range.

〔solvent〕
From the viewpoint of workability and the like, the liquid crystal composition of the present invention preferably contains a solvent.
Examples of the solvent include ketones (e.g., acetone, 2-butanone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone), ethers (e.g., dioxane, tetrahydrofuran, tetrahydropyran, dioxolane, tetrahydrofurfuryl alcohol, and cyclopentyl methyl ether), aliphatic hydrocarbons (e.g., hexane), alicyclic hydrocarbons (e.g., cyclohexane), aromatic hydrocarbons (e.g., benzene, toluene, xylene, and trimethylbenzene), halogenated carbons (e.g., dichloromethane, trichloromethane (chloroform), dichloroethane, dichlorobenzene, and chlorotoluene), and the like. Examples of the organic solvent include organic solvents such as benzene, esters (e.g., methyl acetate, ethyl acetate, ethyl propionate, butyl acetate, diethyl carbonate, etc.), alcohols (e.g., ethanol, isopropanol, butanol, cyclohexanol, etc.), cellosolves (e.g., methyl cellosolve, ethyl cellosolve, 1,2-dimethoxyethane, etc.), cellosolve acetates, sulfoxides (e.g., dimethyl sulfoxide, etc.), amides (e.g., dimethylformamide, dimethylacetamide, N-methylpyrrolidone, N-ethylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, etc.), and heterocyclic compounds (e.g., pyridine, etc.), as well as water.
The solvent may be used alone or in combination of two or more kinds.

Among these solvents, it is preferable to use organic solvents, and it is more preferable to use ketones and/or esters, because the liquid crystal cured layer formed using the liquid crystal composition will have better alignment and improved heat resistance.

[Polymerization initiator]
The liquid crystal composition of the present invention may contain a polymerization initiator.
The polymerization initiator is not particularly limited, but a photosensitive compound, that is, a photopolymerization initiator, is preferred.
The photopolymerization initiator is not particularly limited, and examples of the photopolymerization initiator include α-carbonyl compounds, acyloin ethers, α-hydrocarbon-substituted aromatic acyloin compounds, polynuclear quinone compounds, combinations of triaryl imidazole dimers and p-aminophenyl ketones, acridine and phenazine compounds, oxadiazole compounds, o-acyloxime compounds, acylphosphine oxide compounds, and oxime-type polymerization initiators.
As such a photopolymerization initiator, commercially available products can be used, such as Irgacure-184, Irgacure-907, Irgacure-369, Irgacure-651, Irgacure (Ominirad)-819, Irgacure-OXE-01, and Irgacure-OXE-02, all of which are manufactured by BASF.

When the liquid crystal composition contains a polymerization initiator, the content of the polymerization initiator is preferably 0.01 to 30 mass %, and more preferably 0.1 to 15 mass %, based on the total solid content (100 mass %) of the liquid crystal composition.
The polymerization initiator may be used alone or in combination of two or more. When two or more polymerization initiators are used in combination, the total content is preferably within the above range.

[Chiral Agents]
The liquid crystal composition may contain a chiral dopant.
Chiral agents can be selected according to the purpose, since the direction of helical twist or the helical pitch induced by the agent varies depending on the compound.
The chiral agent is not particularly limited, and examples thereof include known compounds (for example, those described in Liquid Crystal Device Handbook, Chapter 3, Section 4-3, Chiral Agents for TN (twisted nematic) and STN (Super Twisted Nematic), p. 199, edited by the 142nd Committee of the Japan Society for the Promotion of Science, 1989), isosorbide and isomannide derivatives.
Although the chiral agent generally contains an asymmetric carbon atom, an axially asymmetric compound or a planarly asymmetric compound that does not contain an asymmetric carbon atom can also be used as the chiral agent. Examples of the axially asymmetric compound or the planarly asymmetric compound include binaphthyl, helicene, paracyclophane, and derivatives thereof.
The chiral agent may have a polymerizable group.
The polymerizable group of the chiral agent is preferably an unsaturated polymerizable group, an epoxy group or an aziridinyl group, more preferably an unsaturated polymerizable group, and even more preferably an ethylenically unsaturated polymerizable group.

The chiral agent may have a photoisomerisation site.
The photoisomerizable moiety is preferably a cinnamoyl moiety, a chalcone moiety, an azobenzene moiety, or a stilbene moiety, and more preferably a cinnamoyl moiety, a chalcone moiety, or a stilbene moiety.
Examples of the chiral agent include the optically active isosorbide derivatives described in paragraphs [0015] to [0049] of JP-A-2003-313187, the optically active isomannide derivatives described in paragraphs [0015] to [0057] of JP-A-2003-313188, the optically active polyester/amides described in paragraphs [0015] to [0052] of JP-A-2003-313292, and the chiral agents described in paragraphs [0012] to [0053] of WO2018/194157.

When the liquid crystal composition contains a chiral agent, the content of the chiral agent is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, even more preferably 2.0% by mass or less, and particularly preferably less than 1.0% by mass, based on the total mass of the liquid crystal compound, from the viewpoint of facilitating uniform alignment of the liquid crystal compound. The lower limit is not particularly limited, but is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and even more preferably 0.05% by mass or more.
The chiral agent may be used alone or in combination of two or more. When two or more chiral agents are used in combination, the total content is preferably within the above range.

When forming a liquid crystal cured layer having multiple alignment states in one layer, it is preferable to use two or more chiral agents including chiral agent A and chiral agent B that induces a helix in the opposite direction to that of chiral agent A as the chiral agents used in the liquid crystal composition. For example, if the helix induced by chiral agent A is right-handed, the helix induced by chiral agent B will be left-handed.

[Liquid crystal cured layer]
The cured liquid crystal layer of the present invention is a cured liquid crystal layer obtained by fixing the alignment state of the above-mentioned liquid crystal composition of the present invention.
As a method for forming the liquid crystal cured layer, for example, a method in which the above-mentioned liquid crystal composition of the present invention is used to obtain a desired alignment state, and then the liquid crystal composition is fixed by polymerization.
Here, the polymerization conditions are not particularly limited, but in the polymerization by light irradiation, it is preferable to use ultraviolet light. The irradiation amount is preferably 10 mJ/cm ² to 50 J/cm ² , more preferably 20 mJ/cm ² to 5 J/cm ² , further preferably 30 mJ/cm ² to 3 J/cm ² , and particularly preferably 50 to 1000 mJ/cm ^2. In order to promote the polymerization reaction, the polymerization may be carried out under heating conditions.
The liquid crystal cured layer can be formed on any support or alignment film in an optical film described later, or on a polarizer in a polarizing plate described later.

The alignment state of the liquid crystal compound in the liquid crystal cured layer of the present invention may be any of horizontal alignment, vertical alignment, tilt alignment and twist alignment.
In addition, a single layer may have a plurality of orientation states, such as a liquid crystal cured layer having, along the thickness direction, a first region in which the orientation state of liquid crystal compounds twisted along a helical axis extending along the thickness direction is fixed, and a second region in which the orientation state of liquid crystal compounds homogeneously aligned is fixed, as described in WO2021/033640.
In this specification, the term "horizontal alignment" refers to a state in which the major surface of the cured liquid crystal layer (or, when the cured liquid crystal layer is formed on a member such as a support or an alignment film, the surface of the member) is parallel to the long axis direction of the liquid crystal compound. However, it is not required to be strictly parallel, and in this specification, it refers to an alignment in which the angle between the major surface of the cured liquid crystal layer and the long axis direction of the liquid crystal compound is less than 10°.

The liquid crystal cured layer of the present invention is preferably an optically anisotropic layer.
Examples of optically anisotropic layers include a positive A plate, a positive C plate, and an optically anisotropic layer having, along the thickness direction, a first region in which the orientation state of liquid crystal compounds twistedly oriented along a helical axis extending along the thickness direction is fixed, and a second region in which the orientation state of liquid crystal compounds homogeneously oriented is fixed (hereinafter, this embodiment will be abbreviated as "optically anisotropic layer A").

Here, the positive A plate and the positive C plate are defined as follows.
When the refractive index in the slow axis direction (the direction in which the in-plane refractive index is maximum) in the film plane is nx, the refractive index in the direction perpendicular to the in-plane slow axis is ny, and the refractive index in the thickness direction is nz, the positive A plate satisfies the relationship of formula (A1), and the positive C plate satisfies the relationship of formula (C1). Note that the positive A plate has a positive Rth value, and the positive C plate has a negative Rth value.
Formula (A1) nx>ny≒nz
Formula (C1) nz>nx≒ny
It should be noted that the above "≒" includes not only the case where the two are completely identical, but also the case where the two are substantially identical.
Regarding this "substantially the same," for a positive A plate, for example, the case where (ny-nz) x d (where d is the thickness of the film) is -10 to 10 nm, preferably -5 to 5 nm, is also included in "ny ≒ nz," and the case where (nx-nz) x d is -10 to 10 nm, preferably -5 to 5 nm, is also included in "nx ≒ nz." Also, for a positive C plate, for example, the case where (nx-ny) x d (where d is the thickness of the film) is 0 to 10 nm, preferably 0 to 5 nm, is also included in "nx ≒ ny."

When the liquid crystal cured layer of the present invention is a positive A plate, from the viewpoint of functioning as a λ/4 plate, Re(550) is preferably 100 to 180 nm, more preferably 120 to 160 nm, further preferably 130 to 150 nm, and particularly preferably 130 to 145 nm.
Here, the term "λ/4 plate" refers to a plate having a λ/4 function, specifically, a plate having the function of converting linearly polarized light of a certain wavelength into circularly polarized light (or circularly polarized light into linearly polarized light).

An optically anisotropic layer (optically anisotropic layer A) having, along the thickness direction, a first region in which the orientation state of liquid crystal compounds twistedly oriented along a helical axis extending along the thickness direction is fixed, and a second region in which the orientation state of liquid crystal compounds homogeneously oriented is fixed will be described in detail.
When the thickness of the first region of the optically anisotropic layer A is d1 (nm) and the refractive index anisotropy of the first region measured at a wavelength of 550 nm is Δn1, it is preferable that the first region satisfies the following formula (1-1), in order to suitably apply the optically anisotropic layer to a circular polarizing plate.
Formula (1-1) 100 nm≦Δn1d1≦240 nm
Among these, it is more preferable to satisfy the formula (1-2), and it is even more preferable to satisfy the formula (1-3).
Formula (1-2) 120 nm≦Δn1d1≦220 nm
Formula (1-3) 140 nm≦Δn1d1≦200 nm
The refractive index anisotropy Δn1 means the refractive index anisotropy of the first region.

The absolute value of the twist angle of the liquid crystal compound in the first region is not particularly limited, but is preferably 60 to 120°, and more preferably 70 to 110°, in that the optically anisotropic layer can be suitably applied to a circular polarizer. The twist angle is measured using an Axoscan from Axometrics, Inc., and the company's instrument analysis software.

Furthermore, when the thickness of the second region of the optically anisotropic layer A is d2 (nm) and the refractive index anisotropy of the second region measured at a wavelength of 550 nm is Δn2, it is preferable that the second region satisfies the following formula (2-1), in order to suitably apply the optically anisotropic layer to a circular polarizing plate.
Formula (2-1) 100 nm≦Δn2d2≦240 nm
Among these, it is more preferable to satisfy the formula (2-2), and it is even more preferable to satisfy the formula (2-3).
Formula (2-2) 120 nm≦Δn2d2≦220 nm
Formula (2-3) 140 nm≦Δn2d2≦200 nm
The refractive index anisotropy Δn2 means the refractive index anisotropy of the second region.

[Optical film]
The optical film of the present invention is an optical film having the liquid crystal cured layer of the present invention.
The structure of the optical film will be described with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view showing an example of the optical film.
It should be noted that FIG. 1 is a schematic diagram, and the thickness and positional relationships of the layers do not necessarily correspond to the actual ones, and the support and alignment film shown in FIG. 1 are both optional components.

An optical film 10 shown in FIG. 1 comprises, in this order, a support 16, an alignment film 14, and a liquid crystal cured layer 12 which is a cured product of the liquid crystal composition of the present invention.
The liquid crystal cured layer 12 may be a laminate of two or more different liquid crystal cured layers. For example, when the polarizing plate of the present invention described later is used as a circular polarizing plate, or when the optical film of the present invention is used as an optical compensation film for an IPS (In-Plane-Switching) type or FFS (Fringe-Field-Switching) type liquid crystal display device, it is preferably a laminate of a positive A plate and a positive C plate.
Moreover, the cured liquid crystal layer may be peeled off from the support and used alone as an optical film.
Various members used in the optical film will be described in detail below.

[Liquid crystal cured layer]
The liquid crystal cured layer in the optical film of the present invention is the above-mentioned liquid crystal cured layer of the present invention.
In the optical film, the thickness of the cured liquid crystal layer is not particularly limited, but is preferably 0.1 to 10 μm, and more preferably 0.5 to 5 μm.

[Support]
As described above, the optical film may have a support as a substrate for forming the liquid crystal cured layer.
Such a support is preferably transparent, and more specifically, preferably has a light transmittance of 80% or more.

Examples of such supports include glass substrates and polymer films. Materials of the polymer film include cellulose-based polymers, acrylic polymers having acrylic acid ester polymers such as polymethyl methacrylate and lactone ring-containing polymers, thermoplastic norbornene-based polymers, polycarbonate-based polymers, polyester-based polymers such as polyethylene terephthalate and polyethylene naphthalate, styrene-based polymers such as polystyrene and acrylonitrile-styrene copolymers (AS resins), polyolefin-based polymers such as polyethylene, polypropylene and ethylene-propylene copolymers, vinyl chloride-based polymers, amide-based polymers such as nylon and aromatic polyamide, imide-based polymers, sulfone-based polymers, polyethersulfone-based polymers, polyetheretherketone-based polymers, polyphenylene sulfide-based polymers, vinylidene chloride-based polymers, vinyl alcohol-based polymers, vinyl butyral-based polymers, arylate-based polymers, polyoxymethylene-based polymers, epoxy-based polymers, and polymers made by mixing these polymers.
In addition, a polarizer described later may also function as such a support.

The thickness of the support is not particularly limited, but is preferably 5 to 100 μm, and more preferably 5 to 50 μm. It is preferable that the support is peelable.

[Alignment film]
In the optical film, the liquid crystal cured layer is preferably formed on the surface of the alignment film. When the optical film has any of the above-mentioned supports, the alignment film may be sandwiched between the support and the liquid crystal cured layer. In addition, the above-mentioned support may also serve as the alignment film.

The alignment film is not particularly limited as long as it has the function of aligning the polymerizable liquid crystal compound contained in the composition.
Alignment layers are generally made mainly of polymers. Polymer materials for alignment layers are described in many publications and many commercial products are available.
The polymer material for the alignment film is preferably polyvinyl alcohol, polyimide or any of their derivatives, and more preferably modified or unmodified polyvinyl alcohol.

It is also preferable to use a photo-alignment film as the alignment film, since no object comes into contact with the surface of the alignment film during formation of the alignment film, and deterioration of the surface condition can be prevented.
Examples of the photo-alignment film include, but are not limited to, an alignment film formed from a polymer material such as a polyamide compound and a polyimide compound described in paragraphs [0024] to [0043] of WO 2005/096041; a liquid crystal alignment film formed from a liquid crystal alignment agent having a cinnamoyl group described in JP 2012-155308 A; and a product name LPP-JP265CP manufactured by Rolic Technologies.

The thickness of the alignment film is not particularly limited, but from the viewpoint of mitigating surface irregularities that may exist on the support and forming a liquid crystal cured layer with a uniform thickness, the thickness is preferably 0.01 to 10 μm, more preferably 0.01 to 1 μm, and even more preferably 0.01 to 0.5 μm.

[Other Liquid Crystal Cured Layers]
In the optical film, the cured liquid crystal layer of the present invention may be formed on the surface of another cured liquid crystal layer, or another cured liquid crystal layer may be formed on the surface of the cured liquid crystal layer of the present invention.
Here, other examples of the liquid crystal cured layer include a liquid crystal cured layer obtained by fixing the above-mentioned liquid crystal composition of the present invention in a desired alignment state, and a liquid crystal cured layer (light absorption anisotropic film) obtained by fixing the alignment state of a composition containing the above-mentioned liquid crystal compound, a polymerization initiator, a dichroic material, a surfactant, a solvent, etc.

[Ultraviolet absorber]
In consideration of the influence of external light (particularly ultraviolet light), the optical film may contain an ultraviolet (UV) absorbing agent.
The ultraviolet absorbing agent may be contained in the cured liquid crystal layer, or may be contained in a member other than the cured liquid crystal layer constituting the optical film. A suitable example of the member other than the cured liquid crystal layer is the support.
Any conventionally known ultraviolet absorbent capable of expressing ultraviolet absorbing properties can be used as the ultraviolet absorbent. Among such ultraviolet absorbents, benzotriazole-based or hydroxyphenyltriazine-based ultraviolet absorbents are preferred from the viewpoint of obtaining ultraviolet absorbing ability (ultraviolet ray blocking ability) that is high in ultraviolet absorbing properties and is used in image display devices.
In order to broaden the absorption width of ultraviolet light, it is also preferable to use two or more ultraviolet absorbents having different maximum absorption wavelengths in combination.

Examples of ultraviolet absorbers include Tinuvin 400, Tinuvin 405, Tinuvin 460, Tinuvin 477, Tinuvin 479, and Tinuvin 1577 (all manufactured by BASF).

[Polarizer]
The polarizing plate of the present invention has the above-mentioned optical film of the present invention and a polarizer.
When the liquid crystal cured layer (optically anisotropic layer) of the optical film is a positive A plate, from the viewpoint of suitable application to a circular polarizing plate or the like, the angle between the slow axis of the positive A plate and the absorption axis of a polarizer described later is preferably 30 to 60°, more preferably 40 to 50°, further preferably 42 to 48°, and particularly preferably 45°.
Here, the "slow axis" refers to the direction in the plane of the cured liquid crystal layer in which the refractive index is maximum, and the "absorption axis" of the polarizer refers to the direction in which the absorbance is highest.
When the liquid crystal cured layer (optically anisotropic layer) of the optical film is the above-mentioned optically anisotropic layer A, from the viewpoint of suitably applying the optically anisotropic layer A to a circular polarizing plate or the like, the absolute value of the angle between the in-plane slow axis of the second region in which the orientation state of the homogeneously oriented liquid crystal compound is fixed and the absorption axis of the polarizer is preferably 5 to 25°, and more preferably 10 to 20°.
The polarizing plate can also be used as an optical compensation film in an IPS or FFS liquid crystal display device.
When the polarizing plate is used as an optical compensation film for an IPS-type or FFS-type liquid crystal display device, it is preferable that the above-mentioned optically anisotropic layer is at least one plate of a laminate of a positive A plate and a positive C plate, and the angle between the slow axis of the positive A plate layer and the absorption axis of a polarizer described later is perpendicular or parallel, and specifically, it is more preferable that the angle between the slow axis of the positive A plate layer and the absorption axis of a polarizer described later is 0 to 5° or 85 to 95°.
When the polarizing plate of the present invention is used in an image display device described later, it is preferable that the angle between the slow axis of the cured liquid crystal layer and the absorption axis of the polarizer described later is parallel or perpendicular.
In this specification, "parallel" does not require that they be strictly parallel, but means that the angle between one and the other is less than 10°. In addition, in this specification, "orthogonal" does not require that they be strictly orthogonal, but means that the angle between one and the other is more than 80° and less than 100°.

[Polarizer]
The polarizer is not particularly limited as long as it is a member having a function of converting light into a specific linearly polarized light, and a conventionally known absorptive polarizer, reflective polarizer, and coating type polarizer can be used.
Examples of the absorption-type polarizer include an iodine-based polarizer, a dye-based polarizer using a dichroic dye, and a polyene-based polarizer. The iodine-based polarizer and the dye-based polarizer include a coating-type polarizer and a stretching-type polarizer, both of which can be applied. A polarizer produced by adsorbing iodine or a dichroic dye to polyvinyl alcohol and stretching the resulting product is preferred.
Examples of the coating type polarizer include a polarizer containing a cured liquid crystal compound and a dichroic dye.
Examples of reflective polarizers include polarizers in which thin films with different birefringence are laminated, wire grid polarizers, and polarizers in which a cholesteric liquid crystal having a selective reflection region is combined with a quarter-wave plate.

The thickness of the polarizer is not particularly limited, but is preferably 3 to 60 μm, more preferably 3 to 30 μm, and even more preferably 3 to 10 μm.

[Adhesive Layer]
In the polarizing plate, a pressure-sensitive adhesive layer may be disposed between the cured liquid crystal layer in the optical film and the polarizer.
Examples of materials for forming the pressure-sensitive adhesive layer used for laminating the cured product and the polarizer include members formed of substances having a ratio of storage modulus G' to loss modulus G" (tan δ=G"/G') of 0.001 to 1.5 measured with a dynamic viscoelasticity measuring device, and include so-called pressure-sensitive adhesives and substances that tend to creep. Examples of pressure-sensitive adhesives include polyvinyl alcohol-based pressure-sensitive adhesives.

[Adhesive Layer]
The polarizing plate may have an adhesive layer disposed between the cured liquid crystal layer and the polarizer in the optical film.
The adhesive layer used for laminating the cured product and the polarizer is preferably a curable adhesive composition that is cured by irradiation with active energy rays or by heating.
Examples of the curable adhesive composition include a curable adhesive composition containing a cationically polymerizable compound, and a curable adhesive composition containing a radically polymerizable compound.
The thickness of the adhesive layer is preferably 0.01 to 20 μm, more preferably 0.01 to 10 μm, and even more preferably 0.05 to 5 μm. If the thickness of the adhesive layer is within this range, no lifting or peeling occurs between the laminated protective layer or liquid crystal cured layer and the polarizer, and adhesive strength that is practically problem-free is obtained. In addition, from the viewpoint of suppressing the generation of air bubbles, the thickness of the adhesive layer is preferably 0.4 μm or more.
For the adhesive layer, for example, paragraphs [0062] to [0080] of JP 2016-35579 A can be referred to, the contents of which are incorporated herein by reference.

[Easy-adhesion layer]
The polarizing plate may have an easy-adhesion layer disposed between the liquid crystal cured layer and the polarizer in the optical film. From the viewpoint of excellent adhesion between the liquid crystal cured layer and the polarizer and further suppressing the occurrence of cracks in the polarizer, the easy-adhesion layer preferably has a storage modulus of 1.0×10 ⁶ Pa to 1.0×10 ⁷ Pa at 85° C. Constituent materials of the easy-adhesion layer include polyolefin-based components and polyvinyl alcohol-based components. The thickness of the easy-adhesion layer is preferably 500 nm to 1 μm.
For the easy-adhesion layer, for example, paragraphs [0048] to [0053] of JP 2018-36345 A can be referred to, the contents of which are incorporated herein by reference.

[Image display device]
The image display of the present invention is an image display having the optical film of the present invention or the polarizing plate of the present invention.
The display element used in the image display device is not particularly limited, and examples thereof include a liquid crystal cell, an organic electroluminescence (hereinafter, abbreviated as "organic EL (Electro Luminescence)") display panel, and a plasma display panel. Among these, a liquid crystal cell or an organic EL display panel is preferable.

[Liquid crystal display device]
A liquid crystal display device, which is an example of an image display device, is a liquid crystal display device having the above-mentioned polarizing plate and a liquid crystal cell.
Of the polarizing plates provided on both sides of the liquid crystal cell, it is preferable to use the above-mentioned polarizing plate as the front-side polarizing plate, and it is more preferable to use the above-mentioned polarizing plate as the front-side and rear-side polarizing plates.

<Liquid crystal cell>
The liquid crystal cell used in the liquid crystal display device is preferably in VA (Vertical Alignment) mode, OCB (Optically Compensated Bend) mode, IPS (In-Plane-Switching) mode, FFS (Fringe-Field-Switching) mode, or TN (Twisted Nematic) mode.

[Organic EL display device]
An organic EL display device, which is one example of an image display device, may have, for example, a polarizer, a λ/4 plate made of the above-mentioned liquid crystal cured layer, and an organic EL display panel in this order from the viewing side.
The organic EL display panel is a display panel configured using organic EL elements each having an organic light-emitting layer (organic electroluminescence layer) sandwiched between electrodes (a cathode and an anode). The configuration of the organic EL display panel is not particularly limited, and a known configuration may be adopted.

The present invention will be described in more detail below based on examples. The materials, amounts used, ratios, processing contents, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the examples shown below.

[Raw material synthesis]
[Specific Copolymer B-1]
Macromonomer MM-1′ was synthesized according to the following scheme.

Into a 200 mL three-neck flask equipped with a stirrer, a condenser, a nitrogen inlet tube and a thermometer, 22.0 g of cyclohexanone was placed and heated to 80°C.
Next, under a nitrogen flow, a mixed solution of 100.0 g of Monomer K-1' (Silaplane TM-0701T manufactured by JNC), 1.6 g of dimethyl 2,2'-azobis(isobutyrate), 3.2 g of 6-mercapto-1-hexanol, and 22.0 g of cyclohexanone was added dropwise over 2 hours.
After aging for 2 hours, a mixed solution of 0.2 g of dimethyl 2,2'-azobis(isobutyrate) and 2.0 g of cyclohexanone was added, and the internal temperature was increased to 100° C. and aging was continued for another 3 hours.
Thereafter, the mixture was allowed to cool, and 0.2 g of Neostan U-600 (trade name, manufactured by Nitto Kasei Co., Ltd.), 0.3 g of 4-methoxyphenol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 3.6 g of Karenz AOI (trade name, manufactured by Showa Denko K.K.), and 8.6 g of cyclohexanone were added thereto, followed by reaction at 80° C. in air for 6 hours to obtain macromonomer MM-1′.
The macromonomer MM-1' had a weight average molecular weight of 4,600 and a molecular weight distribution (dispersity) of 1.5. The weight average molecular weight and the molecular weight distribution were calculated in terms of polystyrene by gel permeation chromatography (EcoSEC HLC-8320GPC (manufactured by Tosoh Corporation) under the measurement conditions of THF as an eluent, a flow rate of 0.35 ml/min, and a temperature of 40°C, and the columns used were TSKgel SuperHZM-H, TSKgel SuperHZ4000, and TSKgel SuperHZ200 (manufactured by Tosoh Corporation)).

　Then, copolymer B-1 was synthesized according to the following scheme.

A 200 mL three-neck flask equipped with a stirrer, a cooling tube, a nitrogen inlet tube, and a thermometer was charged with 4.5 g (solid content) of macromonomer MM-1', 10.5 g of liquid crystal compatible monomer Q-8', 20.0 g of cyclohexanone, and 0.7 g of dimethyl 2,2'-azobis(isobutyrate), and heated to 90°C under a nitrogen flow.
After aging at 90° C. for 3 hours, a mixed solution of 0.4 g of dimethyl 2,2′-azobis(isobutyrate) and 4.0 g of cyclohexanone was added, the internal temperature was increased to 105° C., and aging was continued for another 3 hours.
Thereafter, the mixture was allowed to cool, and 108.0 g of cyclohexanone was added and stirred for 15 minutes to obtain a copolymer B-1.
The copolymer B-1 had a weight average molecular weight of 19,200 and a molecular weight distribution (dispersity) of 2.7. The weight average molecular weight and the molecular weight distribution were measured in the same manner as in the macromonomer MM-1'.

[Other Copolymers]
Copolymers other than copolymer B-1 were obtained in the same manner as copolymer B-1, except that the monomers and composition ratios forming the repeating units of the copolymers having the structures shown in the table below were changed. The structures of each copolymer are shown below. * indicates the bond position.

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

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

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

The web (film) obtained by casting was peeled off from the drum, and then dried for 20 minutes in a tenter apparatus, which clips both ends of the web with clips while transporting the film at 30 to 40°C. The web was then post-dried by zone heating while being transported by rolls. The obtained web was knurled and then wound up.
The obtained cellulose acylate film had a thickness of 40 μm, an in-plane retardation Re(550) at a wavelength of 550 nm of 1 nm, and a retardation in the thickness direction Rth(550) at a wavelength of 550 nm of 26 nm.

<Alkaline saponification treatment>
The above-mentioned cellulose acylate film was passed through a dielectric heating roll at a temperature of 60° C., and the film surface temperature was raised to 40° C., and then an alkaline solution having the composition shown below was applied to the band surface of the film using a bar coater in an amount of 14 mL/m ² , and the film was transported for 10 seconds under a steam type far-infrared heater manufactured by Noritake Co., Ltd., which was heated to 110° C. Next, 3 mL/m ² of pure water was applied using the same bar coater. Next, after washing with water using a fountain coater and draining with an air knife three times, the film was transported to a drying zone at 70° C. for 10 seconds and dried to prepare an alkaline saponification-treated cellulose acylate film.

------------------------------------------------------------------
Alkaline solution------------------------------------------------
Potassium hydroxide 4.7 parts by _mass Water 15.8 parts by mass Isopropanol 63.7 parts by mass Surfactant SF-1: _{C14H29O ( CH2CH2O} ) _20H 1.0 part by mass Propylene glycol 14.8 parts by mass

<Formation of alignment film>
On the surface of the cellulose acylate film that had been subjected to the alkaline saponification treatment, an alignment film coating solution having the following composition was continuously coated with a wire bar #14. The film was dried with hot air at 60° C. for 60 seconds and then with hot air at 100° C. for 120 seconds. The saponification degree of the modified polyvinyl alcohol used was 96.8%.

------------------------------------------------------------------
Alignment film coating liquid --------------------------------------------------
The following modified polyvinyl alcohol-1: 10 parts by weight Water: 170 parts by weight Methanol: 57 parts by weight

Modified polyvinyl alcohol-1 (wherein the numerical value for each repeating unit represents the content (mol %) of each repeating unit relative to the total repeating units.)

[Formation of Cured Liquid Crystal Layer]
The cellulose acylate film prepared above was continuously subjected to rubbing treatment. At this time, the longitudinal direction of the long film was parallel to the transport direction, and the angle between the longitudinal direction of the film (transport direction) and the rotation axis of the rubbing roller was 77.0°. The longitudinal direction of the film (transport direction) was set to 90°, and the counterclockwise direction was expressed as a positive value with the film width direction as the reference (0°) when observed from the film side, and the rotation axis of the rubbing roller was at 13.0°. In other words, the position of the rotation axis of the rubbing roller was rotated 77.0° clockwise with the longitudinal direction of the film as the reference.

The above-mentioned rubbed cellulose acylate film was used as a substrate, and a liquid crystal composition 1 containing a rod-shaped liquid crystal compound having the following composition was applied thereon by using a Giesser coater to form a composition layer. The absolute value of the weighted average helical twisting power of the chiral dopant in the composition layer in step 1 was ^0.0 μm
Next, the obtained composition layer was heated for 60 seconds at 80° C. By this heating, the rod-like liquid crystal compound in the composition layer was aligned in a predetermined direction.
Thereafter, the composition layer was irradiated with ultraviolet light (irradiation amount: 70 mJ/cm 2 ) using a 365 nm wavelength LED lamp (manufactured by Acroedge Co., Ltd.) at 30° C. in oxygen-containing air (oxygen concentration: approximately 20 ^% by volume).
The resulting composition layer was then heated at 80° C. for 10 seconds.
Thereafter, nitrogen purging was performed to adjust the oxygen concentration to 100 volume ppm, and the composition layer was irradiated with ultraviolet light (irradiation dose: 500 mJ/ ^cm2 ) using a metal halide lamp (manufactured by Eye Graphics Co., Ltd.) at 75°C to form a liquid crystal cured layer (optically anisotropic layer) in which the orientation state of the liquid crystal compound was fixed. In this manner, an optical film was produced.

------------------------------------------------------------------
Liquid crystal composition 1
------------------------------------------------------------------
80 parts by weight of the following rod-shaped liquid crystal compound (A) 17 parts by weight of the following precipitation-inhibiting compound (A) 3 parts by weight of the following precipitation-inhibiting compound (B) 4 parts by weight of ethylene oxide-modified trimethylolpropane triacrylate (V#360, manufactured by Osaka Organic Chemical Co., Ltd.)
(manufactured by IGM Resins B.V.) 3 parts by weight of the following left-twisted chiral agent (L1) 0.48 parts by weight of the following right-twisted chiral agent (R1) 0.43 parts by weight Copolymer B-1 0.08 parts by weight Methyl isobutyl ketone 72 parts by weight Ethyl propionate 72 parts by weight

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

Precipitation-inhibiting compound (A): Me represents a methyl group.

Precipitation Inhibiting Compound (B)

Left-twisted chiral agent (L1): Bu represents a methyl group.

Right-twisted chiral agent (R1)

The optical film prepared above was cut parallel to the rubbing direction, and the liquid crystal cured layer was observed from the cross-sectional direction with a polarizing microscope. The thickness of the liquid crystal cured layer was 2.6 μm, and the region (second region) of the liquid crystal cured layer with a thickness (d2) of 1.3 μm on the substrate side was homogeneous orientation without twist angle, and the region (first region) of the liquid crystal cured layer with a thickness (d1) of 1.3 μm on the air side (opposite to the substrate) was twisted orientation of the liquid crystal compound.
The optical properties of the optical film were determined using Axoscan from Axometrics and its analysis software (Multi-Layer Analysis). The product (Δn2d2) of Δn2 and thickness d2 (nm) at a wavelength of 550 nm in the second region was 178 nm, the twist angle of the liquid crystal compound was 0°, and the alignment axis angle of the liquid crystal compound relative to the long length direction was −11.0° on the side in contact with the substrate and −11.0° on the side in contact with the first region.
In addition, the product (Δn1d1) of Δn1 and the thickness d1 (nm) at a wavelength of 550 nm in the first region was 180 nm, the twist angle of the liquid crystal compound was 88°, and the alignment axis angle of the liquid crystal compound relative to the longitudinal direction was −11.0° on the side in contact with the second region and −91.0° on the air side.
The alignment axis angle of the liquid crystal compound contained in the cured liquid crystal layer is expressed as negative when it is clockwise (right-handed) and positive when it is counterclockwise (left-handed) with the longitudinal direction of the substrate being taken as 0° as the reference, when observing the substrate from the surface side of the cured liquid crystal layer.
The twisted structure of the liquid crystal compound is expressed by observing the substrate from the surface side of the liquid crystal cured layer, and based on the orientation axis direction of the liquid crystal compound on the surface side (front side), when the orientation axis direction of the liquid crystal compound on the substrate side (rear side) is clockwise (right-handed), it is expressed as negative, and when it is counterclockwise (left-handed), it is expressed as positive.

[Preparation of Polarizer]
A polyvinyl alcohol (PVA) film having a thickness of 80 μm was dyed by immersing it in an aqueous iodine solution having an iodine concentration of 0.05% by mass for 60 seconds at 30° C. Next, the obtained film was longitudinally stretched to 5 times its original length while being immersed in an aqueous boric acid solution having a boric acid concentration of 4% by mass for 60 seconds, and then dried at 50° C. for 4 minutes to obtain a polarizer having a thickness of 20 μm.

[Preparation of Polarizer Protective Film]
A commercially available cellulose acylate film, Fujitac TG40UL (manufactured by Fujifilm Corporation), was prepared and immersed in a 1.5 mol/L aqueous sodium hydroxide solution at 55° C., and then the sodium hydroxide was thoroughly washed off with water. The obtained film was then immersed in a 0.005 mol/L aqueous dilute sulfuric acid solution at 35° C. for 1 minute, and then immersed in water to thoroughly wash off the dilute sulfuric acid solution. Finally, the obtained film was thoroughly dried at 120° C. to produce a polarizer protective film having a saponified surface.

[Preparation of Circular Polarizing Plate]
The optical film prepared above was subjected to a saponification treatment in the same manner as in the preparation of the polarizer protective film described above, and then the above-mentioned polarizer and polarizer protective film were continuously bonded to the substrate surface included in the optical film using a polyvinyl alcohol-based adhesive to prepare a long-sized circular polarizing plate.
That is, the circular polarizing plate had a polarizer protective film, a polarizer, a substrate, and a cured liquid crystal layer in this order.
The absorption axis of the polarizer coincided with the longitudinal direction of the circular polarizing plate, the rotation angle of the in-plane slow axis of the second region relative to the absorption axis of the polarizer was 11.0°, and the rotation angle of the in-plane slow axis of the surface of the first region opposite the second region side relative to the absorption axis of the polarizer was 91.0°.
The rotation angle of the in-plane slow axis is expressed as an angle value that is positive in the counterclockwise direction and negative in the clockwise direction when observing the liquid crystal cured layer from the polarizer side, with the longitudinal direction of the substrate being taken as 0° as the reference.

[Examples 2 to 9 and Comparative Examples 1 and 2]
Liquid crystal compositions 2 to 9, 11 and 12 were obtained in the same manner as in Example 1, except that the copolymer B-1 in Example 1 was changed to the copolymers shown in the table below.
Moreover, using these liquid crystal compositions, a liquid crystal cured layer, an optical film, and a circularly polarizing plate were obtained in the same manner as in Example 1.

[Example 10]
An optical film and a circularly polarizing plate were obtained in the same manner as in Example 1, except that the liquid crystal composition 1 in Example 1 was changed to the liquid crystal composition 10 and a liquid crystal cured layer (cholesteric liquid crystal layer R1) was formed by the following procedure.

[Formation of Cured Liquid Crystal Layer]
A liquid crystal composition 10 having the following composition was prepared.
───────────────────────────―─────
Liquid crystal composition 10
------------------------------------------------------------------
- 80 parts by mass of discotic liquid crystal compound (compound 101 below) - 20 parts by mass of discotic liquid crystal compound (compound 102 below) - 10 parts by mass of polymerizable monomer 1 below - 0.3 parts by mass of copolymer B-10 - 3 parts by mass of polymerization initiator 1 below - 3.03 parts by mass of chiral agent 1 below - 0.2 parts by mass of vertical alignment agent 1 below - 290 parts by mass of methyl ethyl ketone - 50 parts by mass of cyclohexanone

Chiral Agent 1

Vertical alignment agent 1

The prepared liquid crystal composition 10 was applied to a rubbed cellulose acylate film prepared in the same manner as in Example 1 using a bar coater. The coating film was then dried at 70° C. for 2 minutes, and the solvent was evaporated, followed by heating and aging at 115° C. for 3 minutes to obtain a uniform alignment state. The coating film was then held at 45° C. and irradiated with ultraviolet light (300 mJ/cm ² ) using a high-pressure mercury lamp under a nitrogen atmosphere to form a cholesteric liquid crystal layer R1 that reflects red right-handed circularly polarized light. The cross section of the cholesteric liquid crystal layer R1 was observed with a scanning electron microscope (SEM), and the film thickness was 2.8 μm. It was also confirmed that the cholesteric liquid crystal layer R1 was vertically aligned.

[Evaluation of Leveling Properties]
The static surface tension of each of the liquid crystal compositions shown in the table below was measured twice using a static surface tensiometer (model: CBVP-Z) manufactured by Kyowa Interface Science Co., Ltd., and the average value was evaluated according to the following criteria.
"A": Less than 26.0 mN/m "B": 26.0 mN/m or more, less than 26.5 mN/m "C": 26.5 mN/m or more, less than 27.5 mN/m "D": 27.5 mN/m or more, less than 28.5 mN/m "E": 28.5 mN/m or more

[Evaluation of compatibility]
When evaluating liquid crystal compositions 1 to 9, 11, and 12, the contents of methyl isobutyl ketone and ethyl propionate were changed to 54 parts by mass, respectively, and when evaluating liquid crystal composition 10, the contents of methyl ethyl ketone and cyclohexanone were changed to 203 parts by mass and 35 parts by mass, respectively, in the contents of the various components in the above-mentioned liquid crystal composition. Except for this, a compatibility evaluation composition corresponding to each Example was prepared in the same manner as for each liquid crystal composition. Each compatibility evaluation composition was measured for absorbance using a Shimadzu Corporation ultraviolet-visible-near infrared spectrophotometer (model number: UV-2600) with a cell length of 10 mm, a measurement wavelength range of 500 to 700 nm, a scan speed of high speed, a sampling pitch of 1 nm, and a slit width of 1 mm, and the absorbance at a wavelength of 660 nm was evaluated according to the following evaluation criteria. Note that a reference composition containing the same components as the compatibility evaluation composition except that it did not contain the copolymer was used as a reference.
"A": Less than 0.03 "B": 0.03 or more, less than 0.06 "C": 0.06 or more, less than 0.15 "D": 0.15 or more, less than 0.30 "E": 0.30 or more

The evaluation results are shown in the table below.
The "Requirement" column indicates whether requirement 1 or requirement 2 is met.
The "Formula" column of "Polymer chain A" indicates whether the repeating unit contained in polymer chain A corresponds to any of the repeating units represented by formulas (1) and (b1) to (b5).
The column "Content of repeating unit A (% by mass)" of "Repeating unit B" indicates the content (% by mass) of repeating unit A relative to the total mass of repeating unit B.
The column "Mw of monomer" for "Repeating unit B" indicates the weight average molecular weight of the monomer (macromonomer) from which repeating unit B is derived.
The column "Content (mass %)" of "Repeating unit B" indicates the content of repeating unit B relative to the total mass of repeating unit C and repeating unit B in the copolymer.
The "Formula" column of "Repeating unit C" indicates whether the repeating unit C corresponds to any of the repeating units represented by formulas (1) and (b1) to (b5).
The "Content (mass %)" column for "Repeating unit C" indicates the content of repeating unit C relative to the total mass of repeating unit C and repeating unit B in the copolymer. However, when the copolymer does not have repeating unit B but has repeating unit C and other repeating units, the content of repeating unit C relative to the total mass of repeating unit C and other repeating units in the copolymer is indicated.
The column "Content of repeating unit Z (% by mass)" in "Other repeating units" indicates the content (% by mass) of repeating unit Z relative to the total mass of other repeating units. Note that repeating unit Z is a repeating unit contained in other repeating units.
The column "Mw of monomer" in "Other repeating units" indicates the weight average molecular weight of the monomer (macromonomer) from which the other repeating units are derived.
The column "Content (mass %)" of "Other repeating units" indicates the content of other repeating units relative to the total mass of repeating unit C and other repeating units in the copolymer.
The "Mw" column indicates the weight average molecular weight of the copolymer.

The results shown in Table 1 above show that when the liquid crystal composition does not contain the specific copolymer, the compatibility or leveling properties are poor (Comparative Examples 1 and 2).

In contrast, it was found that when a specific copolymer is blended, it is possible to provide a liquid crystal composition that contains a copolymer that has excellent compatibility with the liquid crystal compound and has excellent leveling properties. (Examples 1 to 10)

It was found that when the weight average molecular weight of the monomer from which the repeating unit B is derived is 2,000 to 20,000, the leveling property is more excellent (comparison between Example 1 and Example 2, etc.).
It was found that when the specific copolymer contains a repeating unit represented by any one of formulas (b1) to (b4), the compatibility with the liquid crystal compound is superior (e.g., comparison between Example 1 and Example 5).
It was found that when the weight average molecular weight of the specific copolymer is 8,000 to 1,000,000, the leveling property is more excellent (comparison between Examples 1 and 2 and Example 6, etc.).
It was found that when Rh is a substituent containing two or more groups represented by formula (2), the leveling property was more excellent (comparison between Examples 1 and 2 and Example 7, etc.).
It was found that when the content of repeating unit B is 0.1 to 40% by mass based on the total mass of repeating unit B and repeating unit C, the compatibility is better (eg, comparison between Example 1 and Example 9).

REFERENCE SIGNS LIST 10 Optical film 12 Liquid crystal cured layer 14 Orientation film 16 Support

Claims (12)

A liquid crystal composition comprising a copolymer and a liquid crystal compound,
The liquid crystal composition according to claim 1, wherein the copolymer contains a repeating unit B having a polymer chain containing a repeating unit A, and a repeating unit C different from the repeating unit B, and satisfies Requirement 1 or Requirement 2.
Requirement 1: The repeating unit A is a repeating unit represented by any one of the following formulas (b1), (b2) and (b5), and the repeating unit C is a repeating unit represented by the following formula (1).
Requirement 2: The repeating unit A is a repeating unit represented by the following formula (1), and the repeating unit C is a repeating unit represented by any one of the following formulas (b1) to (b5).

In the formula (1),
R ¹¹ and R ¹² each independently represent a hydrogen atom or an alkyl group.
R ¹³ represents a hydrogen atom or a substituent.
L ¹¹ represents —O— or —NR ^Z11 —, where R ^Z11 represents a hydrogen atom or a substituent.
L ¹² represents a single bond or a divalent linking group.
Rh represents a substituent X. The substituent X is a substituent containing two or more groups represented by the following formula (2), or a branched hydrocarbon group having 10 or more carbon atoms and containing two or more carbon atoms selected from tertiary carbon atoms and quaternary carbon atoms.

In the formula (2),
* indicates the bond position.
R ³¹ , R ³² and R ³³ each independently represent an alkyl group, an alkenyl group, an aryl group or an alkylenearyl group.
In a substituent containing two or more groups represented by the formula (2), a plurality of R ³¹ , R ³² and R ³³ may be the same or different.

In the formulas (b1) to (b5),
R ²¹ , R ²² , R ²⁴ and R ²⁵ each independently represent a hydrogen atom or an alkyl group.
R ²³ and R ²⁶ each independently represent a hydrogen atom or a substituent.
L ¹ and L ² each independently represent -O- or -NR ^Z1 -, where R ^Z1 represents a hydrogen atom or a substituent.
^L3 represents a single bond or a divalent linking group.
SP ¹ and SP ² each independently represent a spacer group.
^SP3 represents a single bond or a divalent linking group.
^Ph1 represents a ring structure containing two or more monocyclic aromatic rings.
^M1 represents a mesogenic group.
^T1 represents a terminal group other than the substituent X.
D represents a mesogenic group having a valence of m, which is derived from a discotic liquid crystal compound.
m represents an integer of 3 to 8, and a plurality of R ²¹ , R ²² , R ²³ , L ¹ and SP ³ in the formula (b4) may be the same or different.
Rp represents a polyoxyalkylene group.
Rq represents a substituent other than the substituent X, or a hydrogen atom. The liquid crystal composition according to claim 1, wherein the repeating unit B contains a sulfur atom. The liquid crystal composition according to claim 1, wherein the weight average molecular weight of the copolymer is 8,000 to 1,000,000. The liquid crystal composition according to claim 1, wherein the weight average molecular weight of the monomer from which the repeating unit B is derived is 2,000 to 20,000. The liquid crystal composition according to claim 1, wherein the copolymer contains a repeating unit represented by any one of formulas (b1) to (b4). The liquid crystal composition according to claim 1, wherein the content of the repeating unit B is 0.1 to 40% by mass relative to the total mass of the repeating unit B and the repeating unit C. The liquid crystal composition according to claim 1, wherein the liquid crystal compound is a polymerizable liquid crystal compound. The liquid crystal composition according to claim 7, wherein the polymerizable liquid crystal compound is at least one type of polymerizable liquid crystal compound selected from the group consisting of polymerizable rod-shaped liquid crystal compounds and polymerizable discotic liquid crystal compounds. A liquid crystal cured layer obtained by fixing the alignment state of the liquid crystal composition according to any one of claims 1 to 8. An optical film having the liquid crystal cured layer according to claim 9. A polarizing plate comprising the optical film according to claim 10 and a polarizer. An image display device comprising the optical film according to claim 10.