JP7467850B2 - Composition for forming anisotropic dye film, anisotropic dye film, and optical element - Google Patents

Description

The present invention relates to an anisotropic dye film formed by applying a liquid crystal composition, in particular a composition for forming an anisotropic dye film exhibiting high dichroism, which is useful for polarizing films provided in display elements such as light control elements, liquid crystal elements (LCDs), and organic electroluminescence elements (OLEDs), and an anisotropic dye film, as well as an optical element.

In LCDs, linear and circular polarizing films are used to control the optical rotation and birefringence of the display. In OLEDs, circular polarizing films are also used to prevent reflection of external light in bright places.
Conventionally, examples of such polarizing films include a polarizing film made of polyvinyl alcohol (PVA) dyed with low concentration of iodine (iodine-PVA polarizing film) (Patent Document 1).
It is also known that an anisotropic dye film formed by coating a liquid crystal composition containing a dye functions as a polarizing film (Patent Document 2).

Japanese Patent Application Laid-Open No. 1-105204 JP 2004-535483 A

However, such low-concentration iodine-PVA polarizing plates can have problems such as the iodine sublimating or deteriorating, causing a change in color, or warping due to relaxation of the stretching of the PVA, depending on the usage environment.

In addition, in a polarizing film formed by applying a liquid crystal composition containing a dye, there is a problem that high light absorption selectivity cannot be obtained, or when a high light absorption selectivity is attempted, difficulties may arise in the process. Furthermore, when used for LCD and OLED applications, good appearance performance is also required.
Under such circumstances, there is a demand for a polarizing film that has high light absorption selectivity even in a thin film and has a good appearance.

In the manufacturing process of an anisotropic dye film, the composition for forming an anisotropic dye film is applied to a substrate, and then dried. In the orientation process, which is performed as necessary, the composition for forming an anisotropic dye film is heated to a temperature equal to or higher than the isotropic phase appearance temperature, and then cooled so as to form a liquid crystal phase again. Alternatively, the composition is heated to a temperature at which a liquid crystal phase with high fluidity (such as a nematic phase) appears, and then cooled. For this reason, an anisotropic dye film-forming composition having a high isotropic phase appearance temperature requires a higher temperature in the above orientation process, which is disadvantageous in terms of the stability of the dye and liquid crystal compound, ease of handling of the process, energy consumption, etc. Furthermore, if the liquid crystal compound has a polymerizable group, unintended thermal polymerization may occur due to heating at a high temperature in the above reorientation process. In addition, the degree of freedom in selecting a substrate that can be used is reduced depending on the heat resistance temperature of the substrate.

On the other hand, in order to increase the dichroism of the anisotropic dye film formed from the composition for forming an anisotropic dye film, it is considered to increase the ratio of the long axis to the short axis of the core of the liquid crystal compound molecule contained in the composition for forming an anisotropic dye film.
However, when the core of a liquid crystal compound molecule is made larger, the melting point (phase transition point between solid and liquid) and the isotropic phase appearance temperature (phase transition point between liquid crystal and liquid) of the liquid crystal compound tend to become higher.
That is, in order to lower the isotropic phase appearance temperature, it is conceivable to reduce the size of the core of the liquid crystal compound molecule. However, by reducing the size of the core of the liquid crystal compound molecule, the ratio of the long axis to the short axis of the core of the liquid crystal compound molecule becomes smaller, and as a result, the dichroism of the anisotropic dye film formed from the composition for forming an anisotropic dye film is reduced.

Under these circumstances, it is desirable to lower the isotropic phase appearance temperature of an anisotropic dye film-forming composition while maintaining high dichroism of the anisotropic dye film formed from the anisotropic dye film-forming composition.

On the other hand, in order to increase the dichroism of the anisotropic dye film formed from the anisotropic dye film-forming composition, it is considered that the ratio of the long axis to the short axis of the core of the liquid crystal compound molecule contained in the anisotropic dye film-forming composition is increased to align the liquid crystal molecules in a uniaxial direction.
However, when the core of a liquid crystal compound molecule is made larger, since the core is made of an aromatic ring such as a benzene ring or an alicyclic ring such as a cyclohexane ring, the molecules tend to be oriented at an angle to the direction of the alignment control force obtained from an alignment film, etc., due to intermolecular interactions.
That is, in order to align the liquid crystal compound molecules in one axis direction, it is conceivable to reduce the core of the liquid crystal compound molecule, thereby reducing the intermolecular interaction and reducing the tilt of the molecules. However, by reducing the core of the liquid crystal compound molecule, the ratio of the major axis to the minor axis of the core of the liquid crystal compound molecule becomes smaller, and as a result, the dichroism of the anisotropic dye film formed from the composition for forming an anisotropic dye film is reduced.

An anisotropic dye film formed from a composition for forming an anisotropic dye film is required to have low haze as an appearance performance. In order to reduce haze, it is possible to suppress defects in the anisotropic dye film that cause haze. Examples of defects in anisotropic dye films include defects in molecular orientation, defects resulting from the internal structure of the film, defects resulting from the film surface structure, and defects resulting from precipitates.

From the viewpoint of practical use and manufacturing, the anisotropic dye film formed from the composition for forming an anisotropic dye film is required to have mechanical strength and a stable anisotropic dye film structure. Polymerization of the anisotropic dye film is considered as a way to impart mechanical strength and stability to the film structure. However, if the degree of polymerization is increased in order to increase the mechanical strength and stability of the film structure, the polymerization strain in the process of polymerizing the composition for forming an anisotropic dye film may easily cause defects in the anisotropic dye film, and there is a risk of increasing haze.

In view of the above problems, the present invention aims to provide a polymerizable composition for forming an anisotropic dye film, which can realize a low isotropic phase appearance temperature while maintaining excellent optical performance, particularly a sufficient dichroic ratio, and a further object of the present invention is to provide a composition for forming an anisotropic dye film, which can have low haze and good appearance.
Another object of the present invention is to provide an anisotropic dye film that can maintain excellent optical performance, particularly a sufficient dichroic ratio, and can form a stable structure at a lower temperature. Another object of the present invention is to provide an anisotropic dye film that has low haze, good appearance, and mechanical strength.

The present inventors have found that the above problems can be solved by using a liquid crystal compound having a specific structure in a composition for forming an anisotropic dye film containing a dye and a liquid crystal compound.
That is, the present invention relates to the following.

[1] A composition for forming an anisotropic dye film, comprising a dye and a liquid crystal compound,
The composition for forming an anisotropic dye film, wherein the liquid crystal compound comprises a liquid crystal compound represented by formula (1):
R1-A1-Y1-A2-Y2-A3-R2 ... (1)
In formula (1),
R1 and R2 each independently represent a chain organic group having a polymerizable group;
The polymerizable chain organic group has a sum of the chain lengths of R1 and R2 of 5 or more;
A1 and A3 each independently represent a partial structure represented by formula (2), a divalent organic group, or a single bond;
A2 represents a partial structure represented by formula (2) or a divalent organic group;
-Y1- and -Y2- each independently represent a single bond, -C(=O)O-, -OC(=O)-, -C(=S)O-, -OC(=S)-, -C(=O)S-, -SC(=O)-, -CH ₂ CH ₂ -, -CH=CH-, -C(=O)NH-, -NHC(=O)-, -CH ₂ O-, -OCH ₂ -, -CH ₂ S-, or -SCH ₂ -;
One of A1 and A3 is a partial structure represented by formula (2) or a divalent organic group;
At least one of A1, A2, and A3 is a partial structure represented by formula (2).
-Cy-X2-C≡C-X- ... (2)
In formula (2),
Cy represents a hydrocarbon ring group or a heterocyclic group;
-X- represents -C(=O)O-, -OC(=O)-, -C(=S)O-, -OC(=S)-, -C(=O)S-, -SC(=O)-, -CH ₂ CH ₂ -, -CH=CH-, -C(=O)NH-, -NHC(=O)-, -CH ₂ O-, -OCH ₂ -, -CH ₂ S-, or -SCH ₂ -;
-X2- represents a single bond, -C(=O)O-, -OC(=O)-, -C(=S)O-, -OC(=S)-, -C(=O)S-, -SC(=O)-, -CH ₂ CH ₂ -, -CH=CH-, -C(=O)NH-, -NHC(=O)-, -CH ₂ O-, -OCH ₂ -, -CH ₂ S-, or -SCH ₂ -.
[2] The composition for forming an anisotropic dye film according to [1], wherein --X-- is --C(.dbd.O)O--, --OC(.dbd.O)--, --CH ₂ CH ₂ --, --CH ₂ O--, or --OCH ₂ --.
[3] The composition for forming an anisotropic dye film according to [1] or [2], wherein in the formula (2), Cy is a hydrocarbon ring group, and -X2- is a single bond.
[4] One of A1, A2, and A3 is a partial structure represented by the formula (2), and the other two are each independently a divalent organic group;
In the formula (2), Cy is a hydrocarbon ring group, -X2- is a single bond,
The composition for forming an anisotropic dye film according to any one of [1] to [3], wherein the divalent organic group is a hydrocarbon ring group.
[5] The composition for forming an anisotropic dye film according to any one of [1] to [4], wherein Cy in the formula (2) is a 1,4-phenylene group or a cyclohexane-1,4-diyl group.
[6] The composition for forming an anisotropic dye film according to any one of [1] to [5], wherein Cy in the formula (2) is a 1,4-phenylene group.
[7] The composition for forming an anisotropic dye film according to any one of [1] to [6], wherein the polymerizable chain organic group is a -( _CH2 ) _n -polymerizable group or a -O-( _CH2 ) _n-1 -polymerizable group, where n is an integer.
[8] _-Y1- and -Y2- each independently represent a single bond, -C(=O)O-, -OC(=O)-, _-CH2CH2- , _-CH2O- or _-OCH2- ;
The composition for forming an anisotropic dye film according to any one of [1] to [7], wherein --X-- is --C(.dbd.O)O--, --OC(.dbd.O)--, --CH ₂ CH ₂ --, --CH ₂ O-- or --OCH ₂ --.
[9] The composition for forming an anisotropic dye film according to any one of [1] to [8], wherein one of A1 and A3 is a cyclohexane-1,4-diyl group.
[10] The composition for forming an anisotropic dye film according to any one of [1] to [9], wherein one of A1 and A3 is a partial structure represented by formula (2), and the other is a cyclohexane-1,4-diyl group.
[11] An anisotropic dye film formed using the composition for forming an anisotropic dye film according to any one of [1] to [10].
[12] An optical element comprising the anisotropic dye film according to [11].

The anisotropic dye film-forming composition of the present invention is polymerizable and can realize a low isotropic phase appearance temperature while maintaining excellent optical performance, particularly a sufficient dichroic ratio. Furthermore, the anisotropic dye film-forming composition of the present invention has low haze and good appearance.
Since the anisotropic dye film of the present invention is formed using the anisotropic dye film-forming composition of the present invention, it can maintain excellent optical performance, particularly a sufficient dichroic ratio, and can be formed at a lower temperature. Furthermore, the anisotropic dye film of the present invention has low haze, good appearance, mechanical strength, and a stable structure.
The optical element of the present invention includes the anisotropic dye film of the present invention, and therefore can maintain excellent optical performance, in particular a sufficient dichroic ratio, can form a stable structure at a lower temperature, has low haze and a good appearance, and can include an anisotropic dye film that is capable of having mechanical strength.

The following describes in detail the embodiments of the present invention, but the present invention is not limited to the following embodiments and can be modified in various ways within the scope of the gist of the invention.

The anisotropic dye film in the present invention is a dye film having anisotropy in electromagnetic properties in any two directions selected from a total of three directions in a three-dimensional coordinate system including the thickness direction of the anisotropic dye film and any two orthogonal in-plane directions. Examples of the electromagnetic properties include optical properties such as absorption and refraction, and electrical properties such as resistance and capacitance.
Examples of films having optical anisotropy such as absorption and refraction include polarizing films such as linear polarizing films and circular polarizing films, retardation films, and conductive anisotropic dye films. The anisotropic dye film of the present invention is preferably used as a polarizing film or a conductive anisotropic dye film, and more preferably used as a polarizing film.

[Anisotropic dye film-forming composition]
The composition for forming an anisotropic dye film of the present invention contains a dye and a liquid crystal compound.
The anisotropic dye film-forming composition of the present invention may be in the form of a solution, liquid crystal, or dispersion as long as it is in a state that does not cause phase separation, but the anisotropic dye film-forming composition is preferably in the form of a solution from the viewpoint of ease of application to a substrate. On the other hand, the solid components remaining after removing the solvent from the anisotropic dye film-forming composition are preferably in the form of a liquid crystal phase at any temperature from the viewpoint of alignment on a substrate as described below.
In the present invention, the liquid crystal phase state specifically refers to a liquid crystal state exhibiting both liquid and crystalline properties or intermediate properties, as described on pages 1-16 of "Basics and Applications of Liquid Crystals" (by Shoichi Matsumoto and Ichiro Tsunoda; 1991), and is a nematic phase, a smectic phase, a cholesteric phase, or a discotic phase.

The reason why the composition for forming an anisotropic dye film of the present invention exhibits the above-mentioned effects is not clear, but the following is thought to be the reason.
The liquid crystal compound contained in the composition for forming an anisotropic dye film of the present invention has a high ratio of the long axis to the short axis of the core structure, which makes it easy to uniaxially align the liquid crystal molecules, while the size of the core is controlled to a size that does not cause the isotropic phase appearance temperature to become high. This is thought to enable the realization of a low isotropic phase appearance temperature while maintaining excellent optical performance, in particular a sufficient dichroic ratio.
Furthermore, when a liquid crystal compound has a polymerizable functional group in the immediate vicinity of the liquid crystal core, the molecules are less likely to associate with each other due to the mobility of the polymerizable functional group or steric hindrance, and the liquid crystal compound tends not to exhibit a liquid crystal state. The liquid crystal compound contained in the composition for forming an anisotropic dye film of the present invention has a chain organic group having a polymerizable group as a side chain, and it is believed that by making the sum of the chain lengths 5 or more, a liquid crystal phase can be expressed and a high dichroic ratio can be exhibited.
The liquid crystal compound contained in the composition for forming an anisotropic dye film of the present invention has a chain organic group having a polymerizable group, and it is considered that by making the sum of the chain lengths of the chain organic groups 5 or more, the polymerization distortion that induces defects in the film structure can be alleviated by the chain organic group, and a film with low haze and good appearance can be obtained.
The liquid crystal compound contained in the composition for forming an anisotropic dye film of the present invention has a chain-like organic group having a polymerizable group in its side chain, and the sum of the chain lengths is set to be 5 or more, so that the liquid crystal compound is less susceptible to distortion caused by polymerization even in the polymerization step for forming the anisotropic dye film, and can ensure the molecular orientation of the liquid crystal compound and exhibit a high dichroic ratio. Furthermore, it is believed that an anisotropic dye film with low haze and good appearance can be obtained by suppressing orientation defects and defects in the film structure of the anisotropic dye film.
It is believed that the liquid crystal compound contained in the composition for forming an anisotropic dye film of the present invention has a chain organic group having polymerizable groups on both side chains, and thus a sufficient degree of polymerization can be obtained, making it possible to form an anisotropic dye film having good mechanical strength and film structure stability.

<Liquid Crystal Compound>
In the present invention, the liquid crystal compound refers to a substance that exhibits a liquid crystal state, and specifically refers to a compound that does not directly transition from a crystal to a liquid state but becomes a liquid state via an intermediate state that exhibits properties of both a crystal and a liquid, as described on pages 1 to 28 of "Liquid Crystal Handbook" (Maruzen Co., Ltd., published on October 30, 2000).

The liquid crystal compound contained in the composition for forming an anisotropic dye film of the present invention includes a liquid crystal compound represented by the following formula (1).
R1-A1-Y1-A2-Y2-A3-R2 ... (1)
In formula (1),
R1 and R2 each independently represent a chain organic group having a polymerizable group;
The polymerizable chain organic group has a sum of the chain lengths of R1 and R2 of 5 or more;
A1 and A3 each independently represent a partial structure represented by formula (2), a divalent organic group, or a single bond;
A2 represents a partial structure represented by formula (2) or a divalent organic group;
-Y1- and -Y2- each independently represent a single bond, -C(=O)O-, -OC(=O)-, -C(=S)O-, -OC(=S)-, -C(=O)S-, -SC(=O)-, -CH ₂ CH ₂ -, -CH=CH-, -C(=O)NH-, -NHC(=O)-, -CH ₂ O-, -OCH ₂ -, -CH ₂ S-, or -SCH ₂ -;
One of A1 and A3 is a partial structure represented by formula (2) or a divalent organic group;
At least one of A1, A2, and A3 is a partial structure represented by formula (2).
-Cy-X2-C≡C-X- ... (2)
In formula (2),
Cy represents a hydrocarbon ring group or a heterocyclic group;
-X- represents -C(=O)O-, -OC(=O)-, -C(=S)O-, -OC(=S)-, -C(=O)S-, -SC(=O)-, -CH ₂ CH ₂ -, -CH=CH-, -C(=O)NH-, -NHC(=O)-, -CH ₂ O-, -OCH ₂ -, -CH ₂ S-, or -SCH2-;
-X2- represents a single bond, -C(=O)O-, -OC(=O)-, -C(=S)O-, -OC(=S)-, -C(=O)S-, -SC(=O)-, -CH ₂ CH ₂ -, -CH=CH-, -C(=O)NH-, -NHC(=O)-, -CH ₂ O-, -OCH ₂ -, -CH ₂ S-, or -SCH ₂ -.

(A1, A2 and A3)
A1 and A3 each independently represent a partial structure represented by formula (2), a divalent organic group, or a single bond, and A2 represents a partial structure represented by formula (2) or a divalent organic group.

(Q1)
The divalent organic group in A1, A2, and A3 is not particularly limited, but is preferably a group represented by the following formula (3).
-Q1- ... (3)
In formula (3), Q1 represents a hydrocarbon ring group or a heterocyclic group.

((Hydrocarbon ring group in Q1))
The hydrocarbon ring group for Q1 includes an aromatic hydrocarbon ring group and a non-aromatic hydrocarbon ring group.
The aromatic hydrocarbon ring group includes an unlinked aromatic hydrocarbon ring group and a linked aromatic hydrocarbon ring group.
The non-linked aromatic hydrocarbon ring group is a divalent group of a monocyclic or condensed aromatic hydrocarbon ring, and from the viewpoint of expressing liquid crystal properties, the number of carbon atoms is preferably 6 to 20, more preferably 6 to 14. In addition, in the case of a condensed ring, the number of rings is not particularly limited, but is preferably 1 to 4 from the viewpoint of solubility.
Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysene ring, a triphenylene ring, an acenaphthene ring, a fluoranthene ring, and a fluorene ring.
The linked aromatic hydrocarbon ring group is a divalent group in which a plurality of monocyclic or condensed aromatic hydrocarbon rings are bonded with a single bond and have a bond on an atom constituting the ring. From the viewpoint of expressing liquid crystallinity, the number of carbon atoms in the monocyclic or condensed ring is preferably 6 to 20, more preferably 6 to 14. In the case of condensation, the number of rings is not particularly limited, but from the viewpoint of solubility, 1 to 4 is preferable.
For example, it is a divalent group in which a first monocyclic or fused aromatic hydrocarbon ring having 6 to 20 carbon atoms and a second monocyclic or fused aromatic hydrocarbon ring having 6 to 20 carbon atoms are bonded by a single bond, the first bond being on an atom constituting the first monocyclic or fused aromatic hydrocarbon ring having 6 to 20 carbon atoms, and the second bond being on an atom constituting the second monocyclic or fused aromatic hydrocarbon ring having 6 to 20 carbon atoms. An example of a linked aromatic hydrocarbon ring group is a biphenyl-4,4'-diyl group.

The aromatic hydrocarbon ring group is preferably a non-linked aromatic hydrocarbon ring group.
Among these, the aromatic hydrocarbon ring group is preferably a divalent group of a benzene ring or a divalent group of a naphthalene ring from the viewpoint of solubility, and more preferably a divalent group of a benzene ring (phenylene group). As the phenylene group, a 1,4-phenylene group is preferred because it tends to enhance solubility and molecular orientation of the liquid crystal compound.

The non-aromatic hydrocarbon ring group includes an unlinked non-aromatic hydrocarbon ring group and a linked non-aromatic hydrocarbon ring group.
The unlinked non-aromatic hydrocarbon ring group is a divalent group of a monocyclic or condensed non-aromatic hydrocarbon ring, and from the viewpoint of ease of synthesis, the number of carbon atoms is preferably 3 to 20, and more preferably 4, 6 or 8. In the case of a condensation, the number of rings is not particularly limited, but is preferably 1 to 5 from the viewpoint of solubility.
Examples of the non-aromatic hydrocarbon ring include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, a cyclohexene ring, a norbornane ring, a bornane ring, an adamantane ring, a tetrahydronaphthalene ring, and a bicyclo[2.2.2]octane ring.
The non-linked non-aromatic hydrocarbon ring group includes an alicyclic hydrocarbon ring group that does not have an unsaturated bond as an interatomic bond constituting the ring of the non-aromatic hydrocarbon ring, and an unsaturated non-aromatic hydrocarbon ring group that has an unsaturated bond as an interatomic bond constituting the ring of the non-aromatic hydrocarbon ring. As the non-linked non-aromatic hydrocarbon ring group, an alicyclic hydrocarbon ring group is preferable from the viewpoint of solubility.

The linked non-aromatic hydrocarbon ring group is a divalent group in which a plurality of monocyclic or condensed non-aromatic hydrocarbon rings are bonded by single bonds and have a bond on an atom constituting the ring, or a divalent group in which one or more rings selected from the group consisting of monocyclic aromatic hydrocarbon rings, condensed aromatic hydrocarbon rings, monocyclic non-aromatic hydrocarbon rings, and condensed non-aromatic hydrocarbon rings are bonded by single bonds to a monocyclic or condensed non-aromatic hydrocarbon ring and have a bond on an atom constituting the ring. The number of carbon atoms in the monocyclic or condensed ring is preferably 3 to 20, more preferably 4 to 10, from the viewpoint of ease of synthesis. In the case of condensation, the number of rings is not particularly limited, but is preferably 1 to 5 from the viewpoint of solubility.
For example, it is a divalent group in which a first monocyclic or fused non-aromatic hydrocarbon ring having 3 to 20 carbon atoms and a second monocyclic or fused non-aromatic hydrocarbon ring having 3 to 20 carbon atoms are bonded by a single bond, the first bond is on an atom constituting the first monocyclic or fused non-aromatic hydrocarbon ring having 3 to 20 carbon atoms, and the second bond is on an atom constituting the second monocyclic or fused non-aromatic hydrocarbon ring having 3 to 20 carbon atoms. For example, it is a divalent group in which a monocyclic or fused aromatic hydrocarbon ring having 3 to 20 carbon atoms and a monocyclic or fused non-aromatic hydrocarbon ring having 3 to 20 carbon atoms are bonded by a single bond, the first bond is on an atom constituting the monocyclic or fused aromatic hydrocarbon ring having 3 to 20 carbon atoms, and the second bond is on an atom constituting the monocyclic or fused non-aromatic hydrocarbon ring having 3 to 20 carbon atoms. Examples of the linking non-aromatic hydrocarbon ring group include a bis(cyclohexane)-4,4'-diyl group and a 1-cyclohexylbenzene-4,4'-diyl group.

The non-aromatic hydrocarbon ring group is preferably a non-linked non-aromatic hydrocarbon ring group.
Of these, the non-aromatic hydrocarbon ring group is preferably a divalent group of cyclohexane (cyclohexanediyl group), and as the cyclohexanediyl group, a cyclohexane-1,4-diyl group is preferred from the viewpoints of solubility and molecular orientation of the liquid crystal compound.

((Heterocyclic group in Q1))
The heterocyclic group in Q1 includes an aromatic heterocyclic group and a non-aromatic heterocyclic group. The aromatic heterocyclic group includes a non-linked aromatic heterocyclic group and a linked aromatic heterocyclic group.
The non-linked aromatic heterocyclic group is a divalent group of a monocyclic or condensed aromatic heterocyclic ring, and from the viewpoint of synthesis, the carbon number is preferably 4 to 20, more preferably 4 to 16. In the case of a condensed ring, the number of rings is not particularly limited, but is preferably 1 to 5 from the viewpoint of solubility.
Examples of the aromatic heterocycle include a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, a pyrroloimidazole ring, a pyrrolopyrazole ring, a pyrrolopyrrole ring, a thienopyrrole ring, a thienothiophene ring, a furopyrrole ring, a furofuran ring, a thienofuran ring, a thienothiazole ring, a benzisoxazole ring, a benzisothiazole ring, a benzimidazole ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinoxaline ring, a phenanthridine ring, a benzimidazole ring, a pyrimidine ring, a quinazoline ring, a quinazolinone ring, and an azulene ring.

The linked aromatic heterocyclic group is a divalent group in which a plurality of monocyclic or condensed aromatic heterocyclic rings are bonded with a single bond and have a bond on an atom constituting the ring. The number of carbon atoms in the monocyclic or condensed ring is preferably 4 to 20 from the viewpoint of ease of synthesis, and more preferably 4 to 16. In the case of condensation, the number of rings is not particularly limited, but is preferably 1 to 5 from the viewpoint of solubility.
For example, it is a divalent group in which a first monocyclic ring or fused aromatic heterocyclic ring having 4 to 20 carbon atoms and a second monocyclic ring or fused aromatic heterocyclic ring having 4 to 20 carbon atoms are bonded by a single bond, the divalent group having a first bond on an atom constituting the first monocyclic ring or fused aromatic heterocyclic ring having 4 to 20 carbon atoms, and a second bond on an atom constituting the second monocyclic ring or fused aromatic heterocyclic ring having 4 to 20 carbon atoms.

Non-aromatic heterocyclic groups include unlinked non-aromatic heterocyclic groups and linked non-aromatic heterocyclic groups.
The unlinked non-aromatic heterocyclic group is a divalent group of a monocyclic or condensed non-aromatic heterocyclic ring, and from the viewpoint of ease of synthesis, the number of carbon atoms is preferably 4 to 20. In the case of a condensed ring, the number of rings is not particularly limited, but is preferably 1 to 5 from the viewpoint of solubility.
It is a divalent group of a monocyclic or condensed non-aromatic heterocyclic ring having 4 to 20 carbon atoms. Examples of the non-aromatic heterocyclic ring include a tetrahydrofuran ring, a tetrahydropyran ring, a dioxane ring, a tetrahydrothiophene ring, a tetrahydrothiopyran ring, a pyrrolidine ring, a piperidine ring, a dihydropyridine ring, a piperazine ring, a tetrahydrothiazole ring, a tetrahydrooxazole ring, an octahydroquinoline ring, a tetrahydroquinoline ring, an octahydroquinazoline ring, a tetrahydroquinazoline ring, a tetrahydroimidazole ring, a tetrahydrobenzimidazole ring, and a quinuclidine ring.

The linked non-aromatic heterocyclic group is a divalent group in which a plurality of monocyclic or condensed non-aromatic heterocyclic rings are bonded with a single bond and have a bond on an atom constituting the ring. The number of carbon atoms in the monocyclic or condensed ring is preferably 4 to 20 from the viewpoint of ease of synthesis. In the case of condensation, the number of rings is not particularly limited, but is preferably 1 to 5 from the viewpoint of solubility.
For example, it is a divalent group in which a first monocyclic ring or fused non-aromatic heterocyclic ring having 4 to 20 carbon atoms and a second monocyclic ring or fused non-aromatic heterocyclic ring having 4 to 20 carbon atoms are bonded by a single bond, the divalent group having a first bond on an atom constituting the first monocyclic ring or fused non-aromatic heterocyclic ring having 4 to 20 carbon atoms, and a second bond on an atom constituting the second monocyclic ring or fused non-aromatic heterocyclic ring having 4 to 20 carbon atoms.

The aromatic hydrocarbon ring group, non-aromatic hydrocarbon ring group, aromatic heterocyclic group and non-aromatic heterocyclic group in Q1 may each be substituted with one or more groups selected from the group consisting of RA, -OH, -O-RA, -O-C(=O)-RA, -NH ₂ , -NH-RA, -N(RB)-RA, -C(=O)-RA, -C(=O)-O-RA, -C(=O)-NH ₂ , -C(=O)-NH-RA, -C(=O)-N(RB)-RA, -SH, -S-RA, trifluoromethyl group, sulfamoyl group, carboxy group, sulfo group, cyano group, nitro group and halogen. Here, RA and RB each independently represent a straight-chain or branched alkyl group having 1 to 6 carbon atoms.

The aromatic hydrocarbon ring group, non-aromatic hydrocarbon ring group, aromatic heterocyclic group and non-aromatic heterocyclic group in Q1 are each preferably independently unsubstituted or substituted with a methyl group, a methoxy group, a fluorine atom, a chlorine atom or a bromine atom, and more preferably unsubstituted, in terms of high linearity of the molecular structure, and easy association of the liquid crystal compounds represented by formula (1) with each other and easy development of a liquid crystal state.
The substituents possessed by the aromatic hydrocarbon ring group, the non-aromatic hydrocarbon ring group, the aromatic heterocyclic group and the non-aromatic heterocyclic group may be the same or different, and the aromatic hydrocarbon ring group, the non-aromatic hydrocarbon ring group, the aromatic heterocyclic group and the non-aromatic heterocyclic group may be entirely substituted, entirely unsubstituted, or partially substituted and partially unsubstituted.
In addition, the substituents of the divalent organic groups in A1, A2, and A3 may be the same or different, and all of the divalent organic groups in A1, A2, and A3 may be substituted, all of them may be unsubstituted, or some of them may be substituted and some of them may be unsubstituted.

As a divalent organic group, it is preferable that Q1 is a hydrocarbon ring group, that is, the divalent organic group is a hydrocarbon ring group. As a divalent organic group, a divalent group of a benzene ring (phenylene group) or a divalent group of cyclohexane (cyclohexanediyl group) is more preferable, and a 1,4-phenylene group or a cyclohexane-1,4-diyl group is even more preferable because they can increase the linearity of the molecular structure of the liquid crystal compound.

((Combination of A1, A2, and A3))
When A1 is a partial structure represented by formula (2), formula (1) is
R1-Cy-X2-C≡C-X-Y1-A2-Y2-A3-R2 ... (1A)
may be
R1-X-C≡C-X2-Cy-Y1-A2-Y2-A3-R2 ... (1B)
may be also possible.
When A2 is a partial structure represented by formula (2), formula (1) is
R1-A1-Y1-Cy-X2-C≡C-X-Y2-A3-R2 ... (1C)
may be
R1-A1-Y1-X-C≡C-X2-Cy-Y2-A3-R2 ... (1D)
may be also possible.
When A3 is a partial structure represented by formula (2), formula (1) is
R1-A1-Y1-A2-Y2-Cy-X2-C≡C-X-R2 ... (1E)
may be
R1-A1-Y1-A2-Y2-X-C≡C-X2-Cy-R2 ... (1F)
may be also possible.

Similarly, when two or more of A1, A2, and A3 are partial structures represented by formula (2), the orientation of the partial structure represented by formula (2) may be inverted for each independently.

As described above, A1, A2, and A3 are each independently a partial structure or a divalent organic group represented by formula (2). In addition, A1 and A3 may be single bonds, but A1 and A3 are not both single bonds.
At least one of A1, A2, and A3 represents a partial structure represented by the formula (2). In addition, when one of them is a partial structure represented by the formula (2), the other two are preferably each independently a divalent organic group. Furthermore, it is preferable that one of A1, A2, and A3 is a partial structure represented by the formula (2) in which Cy is a hydrocarbon ring group, and it is preferable that the other two are divalent organic groups, and it is particularly preferable that the divalent organic group is a hydrocarbon ring group. In particular, it is preferable that the hydrocarbon ring group is a 1,4-phenylene group or a cyclohexane-1,4-diyl group, and it is particularly preferable that one of A1 or A3 is a cyclohexane-1,4-diyl group.
It is more preferable that one of A1 and A3 is a partial structure represented by formula (2) and the other is a divalent organic group. It is more preferable that A2 is a divalent organic group. In this case, it is preferable that one of A1 and A3 that is a divalent organic group is a cyclohexane-1,4-diyl group. It is particularly preferable that A2 is a 1,4-phenylene group.

(Formula (2) X)
-X- represents -C(=O)O-, -OC(=O)-, -C(=S)O-, -OC(=S)-, -C(=O)S-, -SC(=O)-, -CH ₂ CH ₂ -, -CH=CH-, -C(=O)NH-, -NHC(=O)-, -CH ₂ O-, -OCH ₂ -, -CH ₂ S-, or -SCH ₂ -.
These structures tend to facilitate linearity and rotational motion around the molecular short axis of the liquid crystal compound, and the above structures with small π-bonding are suitable. Among these, -C(=O)O-, -OC(=O)-, _-CH2CH2- , _-CH2O- , and _{-OCH2- are} more preferred because of the above-mentioned tendencies.
In particular, it is preferred that -Y1- and -Y2- are each independently a single bond, -C(=O)O-, -OC(=O)-, _-CH2CH2- , _-CH2O- , or _-OCH2- , and -X- is -C(=O)O-, _-OC (=O)-, _-CH2CH2- , _-CH2O- , or _-OCH2- . These structures tend to enhance _the molecular orientation of the liquid crystal compound.

(Formula (2) X2)
-X2- represents a single bond, -C(=O)O-, -OC(=O)-, -C(=S)O-, -OC(=S)-, -C(=O)S-, -SC(=O)-, -CH ₂ CH ₂ -, -CH=CH-, -C(=O)NH-, -NHC(=O)-, -CH ₂ O-, -OCH ₂ -, -CH ₂ S-, or -SCH ₂ -.
These structures tend to facilitate linearity and rotational motion around the molecular short axis of the liquid crystal compound, and the above structures with small π-bonding are suitable. Among these, -C(=O)O-, -OC(=O)-, -C(=S)O-, -OC(=S)-, -C(=O)S-, -SC(=O)-, -CH=CH-, -C(=O)NH-, and -NHC(=O)- are preferred due to the above-mentioned tendency, and a single bond is more preferred due to higher linearity.

(Formula (2) Cy)
Cy represents a hydrocarbon ring group or a heterocyclic group.
The hydrocarbon ring group or heterocyclic group for Cy has the same meaning as that for Q1 described above, and the preferred range thereof is also the same.
In particular, Cy is preferably a hydrocarbon ring group, more preferably a phenylene group or a cyclohexanediyl group, and even more preferably a 1,4-phenylene group or a cyclohexane-1,4-diyl group, with a 1,4-phenylene group being particularly preferred, since this can increase the linearity of the molecular structure of the liquid crystal compound.
From the viewpoint of enlarging the core of the liquid crystal compound and increasing the dichroism of the anisotropic dye film formed from the anisotropic dye film-forming composition, it is preferred that --Cy-- and --C≡C-- are linked by a group having high linearity.
As a group with high linearity, the above-mentioned -X2- is preferably a single bond or -C(=O)O-, -OC(=O)-, -C(=S)O-, -OC(=S)-, -C(=O)S-, -SC(=O)-, -CH=CH-, -C(=O)NH-, or -NHC(=O)- having π-bonding property, and more preferably a single bond due to its higher linearity.
It is preferable that Cy is a hydrocarbon ring group and --X2-- is a single bond, since this tends to enable the linearity of the molecular structure of the liquid crystal compound to be particularly high.

(R1 and R2)
R1 and R2 each independently represent a chain organic group having a polymerizable group, and the sum of the chain lengths of R1 and R2 is 5 or more.
The chain organic group in R1 and R2 is a monovalent organic group that does not contain a cyclic structure such as the above-mentioned aromatic hydrocarbon ring, non-aromatic hydrocarbon ring, aromatic heterocycle, or non-aromatic heterocycle (however, when the chain organic group in R1 and R2 has a cyclic polymerizable group described later, such as an oxirane ring, oxetane ring, or vinylbenzene ring, the portion excluding the polymerizable group does not contain the above-mentioned cyclic structure).

The chain length of R1 and R2 represents the number of atoms in the main chain of the chain organic group having a polymerizable group (excluding the polymerizable portion of the polymerizable group described below).
The sum of the chain lengths of R1 and R2 is 5 or more, preferably 6 or more, more preferably 7 or more, even more preferably 8 or more, and particularly preferably 9 or more. It is also preferably 36 or less, more preferably 30 or less, even more preferably 24 or less, and particularly preferably 12 or less. When it is equal to or more than the above lower limit, there is a tendency that the effect of expressing a liquid crystal state, lowering the isotropic phase expression temperature, the effect of imparting mechanical strength by polymerization, and the effect of maintaining molecular orientation even in the polymerization step are obtained, and when it is equal to or less than the above upper limit, there is a tendency that the effect of suppressing defects during the formation of an anisotropic dye film is obtained.

As long as the sum of the chain lengths of R1 and R2 is 5 or more, there are no particular limitations on the chain length of each, but the preferred chain length of each of R1 and R2 is independently 1 or more, more preferably 2 or more, even more preferably 3 or more, even more preferably 6 or more, particularly preferably 7 or more, and especially more preferably 8 or more. Also, it is preferably 20 or less, more preferably 15 or less, even more preferably 14 or less, especially preferably 12 or less, and especially more preferably 10 or less. By being above the above lower limit, there is a tendency to obtain the effect of expressing liquid crystallinity, lowering the isotropic phase expression temperature, and the effect of imparting mechanical strength by polymerization, and by being below the above upper limit, there is a tendency to obtain the effect of suppressing defects during the formation of an anisotropic dye film.

Examples of the chain organic group include -( _CH2 ) _m-1 - _CH3 , -O-( _CH2 ) _m-2 - _CH3 , -S-( _CH2 ) _m-2 - _CH3 , -NH-( _CH2 ) _m-2 - _CH3 , -N(-( _CH2 ) _m-2 - _CH3 )-( _CH2 ) _{m'-2- CH3} , -O(C=O)-( _CH2 ) _m-3 - _CH3 , and -C(=O)O-( _CH2 ) _m-3 - _CH3 . Of these, -( _CH2 ) _m-1 - _CH3 and -O-( _CH2 ) _m-2 - _CH3 are preferred from the viewpoint of enhancing the molecular orientation of the liquid crystal compound. Here, m and m' are integers.
The alkyl group in the chain organic group includes a straight-chain or branched alkyl group, and the carbon-carbon bond of the alkyl group may be partially unsaturated, and one or more methylene groups contained in the alkyl group may be displaced by an ethereal oxygen atom, a thioethereal sulfur atom, an amine nitrogen atom (-NH-, -N(RA)-: here, RA represents a straight-chain or branched alkyl group having 1 to 6 carbon atoms), a carbonyl group, an ester bond, an amide bond, -CHF-, _-CF2- , -CHCl-, or _-CCl2- .
The alkyl group in these chain organic groups is preferably a straight-chain alkyl group, which has high molecular linearity and in which some of the carbon atoms in the alkyl group may be unsaturated, and in which one or more methylene groups contained in the alkyl group may be replaced (displaced) by the above-mentioned group.
The chain length of the branched chain organic group is the longest. The chain length of the replaced chain organic group includes the number of atoms of the replaced bond. For example, in the cases of -( _CH2 ) _m-1 - _CH3 , -O-( _CH2 ) _m-2 - _CH3 , -S-( _CH2 ) _m- 2- _CH3 , -NH-( _CH2 ) _m-2 - _CH3 , -O(C=O)-( _CH2 ) _m-3 - _CH3 , and -C(=O)O-( _CH2 ) _m-3 - _CH3 , the chain length is an integer m. In the case of -N(-( _CH2 ) _m1-2 - _CH3 )-( _CH2 ) _m2-2 - _CH3 , the chain length is the larger of the integers m1 and m2.

R1 and R2 each independently have a polymerizable group. The position and number of the polymerizable group in each of R1 and R2 are not particularly limited, but one to three polymerizable groups may be substituted. Substitution with one polymerizable group is particularly preferred because it tends not to hinder the molecular orientation of the liquid crystal compound during polymerization, and substitution with one polymerizable group at the end of the chain organic group described above is particularly preferred because it does not hinder the molecular orientation of the liquid crystal compound and makes it easier to obtain a high degree of polymerization. Furthermore, for both R1 and R2, it is more preferred that one polymerizable group is substituted only at the end of the chain organic group described above, because this improves the molecular symmetry of the liquid crystal compound and makes it easier to align the molecules.

The polymerizable group is a group having a partial structure capable of being polymerized by light, heat, and/or radiation, and is a functional group or atomic group necessary for ensuring the function of polymerization. From the viewpoint of producing an anisotropic dye film, the polymerizable group is preferably a photopolymerizable group.
Examples of the polymerizable group include an acryloyl group, a methacryloyl group, an acryloyloxy group, a methacryloyloxy group, an acryloylamino group, a methacryloylamino group, a vinyl group, a vinyloxy group, an ethynyl group, an ethynyloxy group, a 1,3-butadienyl group, a 1,3-butadienyloxy group, an oxiranyl group, an oxetanyl group, a glycidyl group, a glycidyloxy group, a styryl group, and a styryloxy group. An acryloxy group, a methacryloyloxy group, an acryloylamino group, a methacryloylamino group, an oxiranyl group, a glycidyl group, or a glycidyloxy group is preferred, an acryloyl group, a methacryloyl group, an acryloyloxy group, a methacryloylamino group, a methacryloylamino group, a glycidyl group, or a glycidyloxy group is more preferred, and an acryloyloxy group, a methacryloyloxy group, or a glycidyloxy group is even more preferred.

Specific examples of the chain organic group having a polymerizable group include a -( _CH2 ) _n -polymerizable group,
-O-( _CH2 ) _n-1 -polymerizable group,
-(O) _n1- ( _{CH2CH2O ) n2-} ( _CH2 ) _n3 -polymerizable group,
-(O) _{n1- (CH2)n3-(CH2CH2O ) n2 - polymerizable} group,
is preferable from the viewpoint of molecular alignment of the liquid crystal compound. Among these, the --(CH ₂ ) _n -polymerizable group and the --O--(CH ₂ ) _n-1 -polymerizable group are more preferable from the viewpoint of improving the molecular alignment of the liquid crystal compound and suppressing defects.
In these formulas, n represents an integer, and the chain length of the chain organic group is the number n of atoms in the main chain (meaning the longest chain portion in the chain organic group, and in the case where the chain organic group is substituted with a polymerizable group, means the longest chain portion excluding the polymerizable group).
In the above formula, n1, n2, and n3 each independently represent an integer, and the chain length of the chain organic group is the number of atoms in the main chain (meaning the longest chain portion in the chain organic group, and in the case where the chain organic group is substituted with a polymerizable group, means the longest chain portion excluding the polymerizable group), n1+3*n2+n3.
The chain length n and the chain length n1+3*n2+n3 are preferably 1 or more, more preferably 2 or more, even more preferably 3 or more, still more preferably 6 or more, particularly preferably 7 or more, and particularly preferably 8 or more. They are also preferably 20 or less, more preferably 15 or less, even more preferably 14 or less, particularly preferably 12 or less, and particularly preferably 10 or less. Being equal to or greater than the above lower limit tends to provide an effect of expressing liquid crystallinity, lowering the isotropic phase expression temperature, and providing mechanical strength by polymerization, while being equal to or less than the above upper limit tends to provide an effect of suppressing defects during the formation of an anisotropic dye film.

The chain length of the chain organic group having a polymerizable group will be specifically explained below in a preferred embodiment in the case where the chain organic group having a polymerizable group has only one polymerizable group at the terminal thereof.
-( _CH2 ) _n- CH=CH, -O-( _CH2 ) _n-1- CH=CH, -(CH2) _n-1 -O-CH=CH, -O-( _CH2 ) _n-2 -O-CH=CH, -( _CH2 ) _n-2 -O-(C=O)-CH=CH, -O-( _CH2 ) _{n-3 -} O-(C=O)-CH=CH,

In these formulas, n represents an integer, and the chain length of the chain-like organic group having a polymerizable group is n.

In the case where X and R1 or X and R2 are bonded to each other as in formula (1B) or formula (1E), for example, when A3 is a single bond in formula (1B) or when A1 is a single bond in formula (1E), and R1 or R2 is bonded to Y1 or Y2, it is preferable that R1 or R2 bonded to X, Y1 or Y2 is -( _CH2 ) _m-1 - _CH3 substituted with a polymerizable group, from the viewpoint of enhancing the molecular orientation of the liquid crystal compound.
In addition to the above, R1 or R2 not bonded to X, Y1 or Y2 is preferably -O-(CH ₂ ) _m-2 -CH ₃ substituted with a polymerizable group, from the viewpoint of enhancing the molecular orientation of the liquid crystal compound.

(Y1 and Y2)
-Y1- and -Y2- each independently represent a single bond, -C(=O)O-, -OC(=O)-, -C(=S)O-, -OC(=S)-, -C(=O)S-, -SC(=O)-, -CH ₂ CH ₂ -, -CH=CH-, -C(=O)NH-, -NHC(=O)-, -CH ₂ O-, -OCH ₂ -, -CH ₂ S-, or -SCH ₂ -.
These structures tend to facilitate linearity and rotational motion around the molecular short axis of the liquid crystal compound, and the above structures with small π-bonding are suitable. Among these, a single bond, -C(=O)O-, -OC(=O)-, _-CH2CH2- , _-CH2O- or _{-OCH2- is} more preferred because of the above-mentioned tendency.

In the case where X and Y1 or X and Y2 are bonded to each other as in the formulae (1A), (1C), (1D), and (1F), it is preferable that Y1 bonded to X or Y2 bonded to X is a single bond in terms of the linearity of the liquid crystal compound; it is preferable that the other of -X-, -Y1-, and -Y2- is -C(=O)O- or -OC(=O)-.
Furthermore, when X is not bonded to either Y1 or Y2 as in formula (1B) or (1E), from the viewpoint of the rotational motion about the molecular short axis of the liquid crystal compound, -X- is preferably -CH ₂ CH ₂ -, -CH ₂ O-, or -OCH ₂ -; and both -Y1- and -Y2- are preferably -C(=O)O- or -OC(=O)-.

As formula (1), the above formulas (1A), (1B), (1E), and (1F) are preferred from the viewpoint of lowering the isotropic phase appearance temperature and increasing the molecular orientation.

Specific examples of formula (1) include, but are not limited to, the following compounds:

The liquid crystal compound contained in the composition for forming an anisotropic dye film of the present invention is preferably a liquid crystal compound represented by the formula (1). Here, the liquid crystal compound contained in the composition for forming an anisotropic dye film of the present invention may be one type of liquid crystal compound represented by the formula (1), or two or more types may be used in combination. In addition, liquid crystal compounds other than the liquid crystal compound represented by the formula (1) may be used in combination.

From the viewpoint of processing, the liquid crystal compound contained in the composition for forming an anisotropic dye film of the present invention generally has an isotropic phase appearance temperature of less than 200°C, preferably less than 160°C, more preferably less than 140°C, even more preferably less than 130°C, even more preferably less than 115°C, particularly preferably less than 110°C, and particularly more preferably less than 105°C.
The isotropic phase appearance temperature means the phase transition temperature from liquid crystal to liquid and the phase transition temperature from liquid crystal to liquid crystal. In the present invention, it is preferable that at least one of these phase transition temperatures is within the above range, and it is more preferable that both of these phase transition temperatures are within the above range.

The liquid crystal compound contained in the composition for forming an anisotropic dye film of the present invention can be produced by combining known chemical reactions such as an alkylation reaction, an esterification reaction, an amidation reaction, an etherification reaction, an ipso substitution reaction, and a coupling reaction using a metal catalyst.
For example, the liquid crystal compound contained in the composition for forming an anisotropic dye film of the present invention can be synthesized according to the method described in the Examples or the method described on pages 449 to 468 of "Liquid Crystal Handbook" (Maruzen Co., Ltd., published on October 30, 2000).

<Dye>
In the present invention, a dye is a substance or compound that absorbs at least a part of the wavelengths in the visible light region (380 nm to 780 nm).
Dyes that can be used in the present invention include dichroic dyes. The dichroic dye refers to a dye that has different absorbance in the long axis direction of the molecule and absorbance in the short axis direction. The dye may or may not have liquid crystallinity. The term "liquid crystallinity" refers to the ability to exhibit a liquid crystal phase at any temperature.

Examples of the dye contained in the anisotropic dye film-forming composition of the present invention include azo dyes, quinone dyes (including naphthoquinone dyes, anthraquinone dyes, etc.), stilbene dyes, cyanine dyes, phthalocyanine dyes, indigo dyes, condensed polycyclic dyes (including perylene dyes, oxazine dyes, acridine dyes, etc.), etc. Among these dyes, azo dyes are preferred because they have a large molecular long/short axis ratio and can have a high molecular alignment in the anisotropic dye film.
The azo dye refers to a dye having at least one azo group (-N=N-), and the number of azo groups in one molecule is preferably 1 or more, more preferably 2 or more, and is preferably 6 or less, more preferably 4 or less, and even more preferably 3 or less, from the viewpoints of solubility in a solvent, compatibility with a liquid crystal compound, color tone, and ease of production.

An example of an azo dye is a compound represented by formula (A). The dye represented by formula (A) has good compatibility with the liquid crystal compound represented by formula (1), and when mixed with the liquid crystal compound represented by formula (1), it exhibits a good dichroic ratio.

R11-D1-N=N-(D2-N=N) _p -D3-R12 ... (A)

In formula (A),
D1, D2, and D3 each independently represent a phenylene group which may have a substituent, a naphthylene group which may have a substituent, or a divalent heterocyclic group which may have a substituent;
p represents an integer of 0 to 4;
When p is an integer of 2 or more, multiple D2 may be the same or different from each other;
R11 and R12 are the same or different monovalent organic groups.

D1, D2 and D3 each independently represent a phenylene group which may have a substituent, a naphthylene group which may have a substituent, or a divalent heterocyclic group which may have a substituent.
As the substitution position of the phenylene group, a 1,4-phenylene group is preferred because it provides high molecular linearity.
As the substitution position of the naphthylene group, a 1,4-naphthylene group or a 2,6-naphthylene group is preferred because the linearity of the molecule is high.

The divalent heterocyclic group preferably has 3 or more and 14 or less carbon atoms forming the ring, and more preferably has 10 or less carbon atoms. In particular, a monocyclic or bicyclic heterocyclic group is preferred.
The atom other than carbon constituting the divalent heterocyclic group is at least one selected from a nitrogen atom, a sulfur atom, and an oxygen atom. When the heterocyclic group has a plurality of atoms constituting the ring other than carbon, these atoms may be the same or different.
Specific examples include a pyridinediyl group, a quinolinediyl group, an isoquinolinediyl group, a thiazolediyl group, a benzothiazolediyl group, a thienothiazolediyl group, a thienothiophenediyl group, a benzimidazolidinonediyl group, a benzofurandiyl group, a phthalimidodiyl group, an oxazolediyl group, and a benzoxazolediyl group.

Examples of the substituents that the phenylene group, naphthylene group, and divalent heterocyclic group in D1, D2, and D3 may optionally have include an alkyl group having 1 to 4 carbon atoms; an alkoxy group having 1 to 4 carbon atoms, such as a methoxy group, an ethoxy group, and a butoxy group; a fluorinated alkyl group having 1 to 4 carbon atoms, such as a trifluoromethyl group; a cyano group; a nitro group; a hydroxyl group; a halogen atom; and a substituted or unsubstituted amino group, such as an amino group, a diethylamino group, and a pyrrolidino group (a substituted amino group means an amino group having one or two alkyl groups having 1 to 4 carbon atoms, or an amino group in which two substituted alkyl groups are bonded to each other to form an alkanediyl group having 2 to 8 carbon atoms. An unsubstituted amino group is, for example, -NH _2. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, and a butyl group. Examples of the alkanediyl group having 2 to 8 carbon atoms include an ethylene group, a propane-1,3-diyl group, a butane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, and an octane-1,8-diyl group.
From the viewpoint of high molecular linearity, it is preferably unsubstituted, or if substituted, is preferably substituted with a methyl group, a methoxy group, a hydroxyl group, a fluorine atom, a chlorine atom, a dimethylamino group, a pyrrolidinyl group, or a piperidinyl group.

p represents an integer of 0 to 4. From the viewpoints of solubility in solvents, compatibility with liquid crystal compounds, color tone, and ease of manufacture, p is preferably 1 or more, more preferably 4 or less, and even more preferably 3 or less.

R11 and R12 are the same or different monovalent organic groups.
Examples of the monovalent organic group in R11 and R12 include a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may be branched; an alicyclic alkyl group having 1 to 20 carbon atoms; an alkoxy group having 1 to 20 carbon atoms which may be branched, such as a methoxy group, an ethoxy group, and a butoxy group; a fluorinated alkyl group having 1 to 20 carbon atoms which may be branched, such as a trifluoromethyl group; a cyano group; a nitro group; a hydroxyl group; a halogen atom; and a substituted or unsubstituted amino group such as an amino group, a diethylamino group, and a pyrrolidino group (the substituted amino group means an amino group having one or two alkyl groups having 1 to 20 carbon atoms which may be branched, or an amino group in which two substituted alkyl groups are bonded to each other to form an alkanediyl group having 2 to 20 carbon atoms. An unsubstituted amino group is, for example, -NH _2. Examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, and a butyl group. Examples of the alkanediyl group having 2 to 20 carbon atoms include an ethylene group, a propane-1,3-diyl group, a butane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, and an octane-1,8-diyl group. ), a carboxy group; an alkyloxycarbonyl group having 1 to 20 carbon atoms which may have a branch such as a butoxycarbonyl group; an alkenyl group having 1 to 20 carbon atoms which may have a branch such as an ethenyl group; and a 2-(4-butylphenyl)ethenyl group. any of alkylphenylalkenyl groups; a carbamoyl group; an alkylcarbamoyl group having 1 to 20 carbon atoms, which may have a branch, such as a butylcarbamoyl group; a sulfamoyl group; an alkylsulfamoyl group having 1 to 20 carbon atoms, which may have a branch, such as a butylsulfamoyl group; an acylamino group having 1 to 20 carbon atoms, which may have a branch, such as a butylcarbonylamino group; an acyloxy group having 1 to 20 carbon atoms, which may have a branch, such as a butylcarbonyloxy group; a sulfanyl group; an alkylsulfanyl group having 1 to 20 carbon atoms, such as a butylsulfanyl group; and the chain organic groups having polymerizable groups R1 and R2 in the liquid crystal compound described above.

R11 and R12 may be hydrogen atoms, chain-like groups, aliphatic organic groups ("aliphatic organic groups" includes chain-like and cyclic ones), aliphatic organic groups in which some of the carbons are replaced with nitrogen and/or oxygen ("aliphatic organic groups in which some of the carbons are replaced with nitrogen and/or oxygen" includes chain-like and cyclic ones, and includes aliphatic organic groups in which some of the methyl groups are replaced with hydroxyl groups, oxo groups (=O), amino groups, imino groups, etc.), etc. In one embodiment, hydrogen atoms and chain-like groups are preferred, in another embodiment, hydrogen atoms and aliphatic organic groups are preferred, and in yet another embodiment, hydrogen atoms and aliphatic organic groups in which some of the carbons are replaced with nitrogen and/or oxygen are preferred.

Examples of the chain group include the above-mentioned alkyl group having 1 to 20 carbon atoms, which may be branched; alkoxy group having 1 to 20 carbon atoms, which may be branched; fluorinated alkyl group having 1 to 20 carbon atoms, which may be branched; substituted or unsubstituted amino group (substituted amino group means an amino group having one or two alkyl groups having 1 to 20 carbon atoms, which may be branched. An unsubstituted amino group is _-NH2 ); carboxy group; alkyloxycarbonyl group having 1 to 20 carbon atoms, which may be branched; carbamoyl group; alkylcarbamoyl group having 1 to 20 carbon atoms, which may be branched; sulfamoyl group; alkylsulfamoyl group having 1 to 20 carbon atoms, which may be branched; acylamino group having 1 to 20 carbon atoms, which may be branched; acyloxy group having 1 to 20 carbon atoms, which may be branched; sulfanyl group; alkylsulfanyl group having 1 to 20 carbon atoms, and the like.

Examples of the aliphatic organic group include the above-mentioned alkyl groups having 1 to 20 carbon atoms, which may be branched, and alicyclic alkyl groups having 1 to 20 carbon atoms.
Examples of the aliphatic organic group in which a portion of the carbon atoms is replaced by nitrogen and/or oxygen include the above-mentioned alkoxy group having 1 to 20 carbon atoms which may be branched; a substituted or unsubstituted amino group (a substituted amino group means an amino group having one or two alkyl groups having 1 to 20 carbon atoms which may be branched, or an amino group in which two substituted alkyl groups are bonded to each other to form an alkanediyl group having 2 to 20 carbon atoms. An unsubstituted amino group is, for example, -NH _2. Examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, and a butyl group. Examples of the alkanediyl group having 2 to 20 carbon atoms include an ethylene group, a propane-1,3-diyl group, a butane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, and an octane-1,8-diyl group. ); a carboxy group; an alkyloxycarbonyl group having 1 to 20 carbon atoms which may be branched; a carbamoyl group; an alkylcarbamoyl group having 1 to 20 carbon atoms which may be branched; an acylamino group having 1 to 20 carbon atoms which may be branched; and an acyloxy group having 1 to 20 carbon atoms which may be branched.

R11 and R12 are each preferably independently substituted with a hydrogen atom, an alkyl group having 1 to 10 carbon atoms such as a butyl group, a pentyl group, a hexyl group, a heptyl group, or an octyl group; an alkoxy group having 1 to 10 carbon atoms such as a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, or an octyloxy group; a diethylamino group, a pyrrolidino group, or a piperidinyl group, from the viewpoint of high molecular linearity. In addition, the preferred chain organic groups having polymerizable groups for R1 and R2 in the liquid crystal compound described above are also preferred.

The dye contained in the anisotropic dye film-forming composition of the present invention is not particularly limited, and any known dye can be used.
Examples of known dyes include the dyes (dichroic dyes, dichroic dyes) described in the above-mentioned Patent Document 1, Japanese Patent No. 5982762, Japanese Patent Application Publication No. 2017-025317, and Japanese Patent Application Publication No. 2014-095899.

Specific examples include, but are not limited to, the dyes listed below.

The molecular weight of the dye contained in the composition for forming an anisotropic dye film of the present invention is preferably 300 or more, more preferably 350 or more, and even more preferably 380 or more, and is preferably 1500 or less, more preferably 1200 or less, and even more preferably 1000 or less. Specifically, the molecular weight of the dye contained in the composition for forming an anisotropic dye film of the present invention is preferably 300 to 1500, more preferably 350 to 1200, and even more preferably 380 to 1000.

The content of the dye (dichroic dye) in the composition for forming an anisotropic dye film is, for example, preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and preferably 30 parts by mass or less, and more preferably 10 parts by mass or less, relative to the solid content (100 parts by mass) of the composition for forming an anisotropic dye film. Specifically, the content of the dye (dichroic dye) in the composition for forming an anisotropic dye film is, for example, 0.01 to 30 parts by mass, preferably 0.05 to 10 parts by mass, relative to the solid content (100 parts by mass) of the composition for forming an anisotropic dye film.
If the content of the dye (dichroic dye) is within the above range, the compound contained in the composition for forming an anisotropic dye film of the present invention tends to be polymerized without disturbing the alignment of the liquid crystal compound contained in the composition for forming an anisotropic dye film of the present invention. If the content of the dye (dichroic dye) is equal to or greater than the above lower limit, sufficient light absorption and sufficient polarization performance tend to be obtained. If the content of the dye (dichroic dye) is equal to or less than the above upper limit, the alignment of the liquid crystal molecules tends to be inhibited.
The dye (dichroic dye) may be used alone or in combination of two or more kinds depending on the purpose.

<Solvent>
The anisotropic dye film-forming composition of the present invention may contain a solvent, if necessary.
The solvent that can be used is not particularly limited as long as it can sufficiently disperse or dissolve the dye or other additives in the liquid crystal compound, and examples thereof include alcohol solvents such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, and propylene glycol monomethyl ether; ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, and ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane, and heptane; aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran, dimethoxyethane, ethylene glycol dimethyl ether, and ethylene glycol diethyl ether; fluorine-containing solvents such as perfluorobenzene, perfluorotoluene, perfluorodecalin, perfluoromethylcyclohexane, and hexafluoro-2-propanol; and chlorine-containing solvents such as chloroform, dichloromethane, chlorobenzene, and dichlorobenzene.
These solvents may be used alone or in combination of two or more.

The solvent is preferably one that can dissolve the liquid crystal compound and the dye, and more preferably one that completely dissolves the liquid crystal compound and the dye. In addition, when the liquid crystal compound is a polymerizable compound, the solvent is preferably inactive in the polymerization reaction. In addition, from the viewpoint of applying the anisotropic dye film-forming composition of the present invention, a solvent having a boiling point in the range of 50 to 200°C is preferable.

When the anisotropic dye film-forming composition of the present invention contains a solvent, the content of the solvent in the anisotropic dye film-forming composition is preferably 50 to 98 mass % relative to the total amount (100 mass %) of the composition of the present invention. In other words, the solid content in the anisotropic dye film-forming composition of the present invention is preferably 2 to 50 mass %.
When the solid content in the composition for forming an anisotropic dye film is equal to or less than the upper limit, the viscosity of the composition for forming an anisotropic dye film does not become too high, the thickness of the obtained polarizing film becomes uniform, and unevenness in the polarizing film tends to be less likely to occur.
The solid content can be determined taking into consideration the thickness of the polarizing film to be produced.
The viscosity of the composition for anisotropic dye film of the present invention is not particularly limited as long as a uniform film without unevenness in thickness can be produced by the coating method described below. From the viewpoints of obtaining uniformity in thickness over a large area, productivity such as coating speed, and in-plane uniformity in optical properties, the viscosity is preferably 0.1 mPa·s or more, and is preferably 500 mPa·s or less, more preferably 100 mPa·s or less, and even more preferably 50 mPa·s or less.

<Other additives>
The anisotropic dye film-forming composition of the present invention may further contain, as necessary, other additives such as a polymerizable liquid crystal compound other than the liquid crystal compound represented by the formula (1), a non-polymerizable liquid crystal compound other than the liquid crystal compound represented by the formula (1), a polymerization initiator, a polymerization inhibitor, a polymerization aid, a polymerizable non-liquid crystal compound, a surfactant, a leveling agent, a coupling agent, a pH adjuster, a dispersant, an antioxidant, an organic/inorganic filler, an organic/inorganic nanosheet, an organic/inorganic nanofiber, a metal oxide, etc. By containing the additives, the coating property and stability of the anisotropic dye film-forming composition may be improved, and the stability of the anisotropic dye film formed from the anisotropic dye film-forming composition may be improved.

[Method of producing anisotropic dye film-forming composition]
The method for producing the composition for anisotropic dye film of the present invention is not particularly limited. For example, a dye, a liquid crystal compound, and if necessary, a solvent and other additives are mixed, and the mixture is stirred and shaken at 0 to 80° C. to dissolve the dye. In the case of poor solubility, a homogenizer, a bead mill disperser, etc. may be used.
The method for producing the composition for anisotropic dye film of the present invention may include a filtration step for the purpose of removing foreign matter and the like from the composition.
The anisotropic dye film-forming composition of the present invention may or may not be liquid crystal at any temperature when the solvent is removed from the anisotropic dye film-forming composition, but it is preferable that the composition exhibits liquid crystallinity at any temperature. From the viewpoint of the coating process described below, the anisotropic phase appearance temperature of the anisotropic dye film-forming composition when the solvent is removed from the anisotropic dye film-forming composition is generally less than 200°C, preferably less than 160°C, more preferably less than 140°C, even more preferably less than 130°C, even more preferably less than 115°C, particularly preferably less than 110°C, and particularly more preferably less than 105°C.

[Anisotropic dye film]
The anisotropic dye film of the present invention contains a dye and a liquid crystal compound represented by the above formula (1).
The anisotropic dye film of the present invention may contain a polymerizable liquid crystal compound other than the liquid crystal compound having the partial structure represented by formula (1), a non-polymerizable liquid crystal compound, a polymerization initiator, a polymerization inhibitor, a polymerization aid, a polymerizable non-liquid crystal compound, a non-polymerizable non-liquid crystal compound, a surfactant, a leveling agent, a coupling agent, a pH adjuster, a dispersant, an antioxidant, an organic or inorganic filler, an organic or inorganic nanosheet, an organic or inorganic nanofiber, a metal oxide, or the like.
The anisotropic dye film of the present invention can be formed using the anisotropic dye film-forming composition of the present invention.

The anisotropic dye film of the present invention can function as a polarizing film that obtains linearly polarized light, circularly polarized light, elliptically polarized light, etc. by utilizing the anisotropy of light absorption. In addition, depending on the film formation process and the selection of the composition containing the substrate and organic compound (dye or transparent material), it can also function as a variety of anisotropic dye films with refractive anisotropy, conductive anisotropy, etc.

When the anisotropic dye film of the present invention is used as a polarizing element for a liquid crystal display or an anti-reflection film for an OLED, the orientation characteristics of the anisotropic dye film can be expressed by the dichroic ratio. If the dichroic ratio is 8 or more, it functions as a polarizing element, but it is preferably 15 or more, more preferably 20 or more, even more preferably 25 or more, particularly preferably 30 or more, and especially preferably 40 or more. In addition, the higher the dichroic ratio, the more preferable it is. When the dichroic ratio is equal to or more than the lower limit, it is useful as an optical element, particularly a polarizing element, as described below.
When used as a polarizing element of an anti-reflection film for OLED, even if the performance of peripheral materials such as a retardation film is low, if the performance of the polarizing element is high, the characteristics as an anti-reflection film are improved. Therefore, if the performance of the polarizing element is high, it is easy to simplify the layer structure, and even a thin film structure can easily exhibit sufficient functions, and it can be suitably used in applications where it is used by deforming it, including folding and bending. In addition, it is possible to keep costs low.

The dichroic ratio (D) in the present invention is expressed by the following formula when the dyes are uniformly oriented.
D = Az/Ay
Here, Az is the absorbance observed when the polarization direction of light incident on the anisotropic dye film is parallel to the orientation direction of the anisotropic dye, and Ay is the absorbance observed when the polarization direction of light incident on the anisotropic dye film is perpendicular to the orientation direction.
There is no particular limitation on the absorbance as long as the absorbances are of the same wavelength, and any wavelength may be selected depending on the purpose. However, when expressing the degree of orientation of an anisotropic dye film, it is preferable to use a value corrected for luminosity in a specific wavelength range of 380 nm to 780 nm of the anisotropic dye film, or a value at the maximum absorption wavelength in the visible range.

The transmittance of the anisotropic dye film of the present invention in the visible light wavelength range is preferably 25% or more, more preferably 35% or more, and particularly preferably 40% or more. The transmittance may be the upper limit according to the application. For example, when the degree of polarization is to be increased, the transmittance is preferably 50% or less. With a transmittance in the above range, the film is useful as an optical element, which will be described later, and is particularly useful as an optical element for liquid crystal displays used for color display, and as an anti-reflection film combining an anisotropic dye film and a retardation film.

The anisotropic dye film has a dry thickness of preferably 10 nm or more, more preferably 100 nm or more, and even more preferably 500 nm or more. On the other hand, it is preferably 30 μm or less, more preferably 10 μm or less, even more preferably 5 μm or less, and especially preferably 3 μm or less. When the thickness of the anisotropic dye film is within the above range, uniform orientation of the dye within the film and a uniform film thickness tend to be obtained.

[Method of manufacturing anisotropic dye film]
The anisotropic dye film of the present invention is preferably produced by a wet film-forming method using the anisotropic dye film-forming composition of the present invention.
The wet film-forming method in the present invention is a method in which an anisotropic dye film composition is applied and oriented on a substrate by some method. Therefore, the anisotropic dye film composition only needs to have fluidity, and may or may not contain a solvent. From the viewpoint of viscosity and film uniformity during application, it is more preferable that the composition contains a solvent.
The liquid crystal or dye in the anisotropic dye film may be oriented by shear during the coating process, or may be oriented during the drying process of the solvent. In addition, the liquid crystal or dye may be oriented and laminated on the substrate through a process of heating after coating and drying to re-align the liquid crystal or dye. In the wet film formation method, when the composition for anisotropic dye film is applied to the substrate, the dye or liquid crystal compound self-associates (molecular association state such as liquid crystal state) already in the composition for anisotropic dye film, or during the drying process of the solvent, or after the solvent is completely removed, and orientation occurs in a small area. By applying an external field to this state, orientation in a certain direction can be achieved in a macroscopic region, and an anisotropic dye film having the desired performance can be obtained. In this respect, it is different from the method in which a polyvinyl alcohol (PVA) film or the like is dyed with a solution containing a dye and stretched, and the dye is oriented only in the stretching process. The external field here includes the influence of an orientation treatment layer previously applied to the substrate, shear force, magnetic field, electric field, heat, etc., which may be used alone or in combination. If necessary, a heating step may be performed.

The process of applying the anisotropic dye film composition onto a substrate to form a film, the process of applying an external field to orient the film, and the process of drying the solvent may be performed sequentially or simultaneously.

Methods for applying the anisotropic dye film-forming composition onto a substrate in a wet film-forming method include, for example, a coating method, a dip coating method, an LB film-forming method, a known printing method, etc. There is also a method for transferring the anisotropic dye film thus obtained onto another substrate.

Among these, it is preferable to apply the anisotropic dye film-forming composition onto a substrate by using a coating method.
The orientation direction of the anisotropic dye film may be different from the coating direction. In the present invention, the orientation direction of the anisotropic dye film refers to, for example, the transmission axis (polarization axis) or absorption axis of polarized light in the case of a polarizing film, and refers to the fast axis or slow axis in the case of a retardation film.

The method of applying the composition for anisotropic dye film to obtain an anisotropic dye film is not particularly limited, but examples thereof include the method described in "Coating Engineering" by Harasaki Yuji (published by Asakura Publishing Co., Ltd. on March 20, 1971) on pages 253-277, the method described in "Creation and Application of Molecular Cooperative Materials" edited by Ichimura Kunihiro (published by CMC Publishing Co., Ltd. on March 3, 1998) on pages 118-149, and the method of applying the composition to a substrate having a stepped structure (which may be preliminarily subjected to an orientation treatment) by a slot die coating method, spin coating method, spray coating method, bar coating method, roll coating method, blade coating method, curtain coating method, fountain method, dip method, etc. Among these, the slot die coating method and bar coating method are preferable because they can obtain a highly uniform anisotropic dye film.

The die coater used in the slot die coating method is generally equipped with a coating machine that ejects the coating liquid, a so-called slit die. Slit dies are disclosed, for example, in JP Patent Publication Nos. 2-164480, 6-154687, and 9-131559, "Fundamentals and Applications of Dispersion, Coating, and Drying" (2014, Techno System Co., Ltd., ISBN 9784924728707 C 305), "Wet Coating Technology for Displays and Optical Components" (2007, Information Organization, ISBN 9784901677752), and "Precision Coating and Drying Technology in the Electronics Field" (2007, Technical Information Association, ISBN 9784861041389). These known slit dies can be used to coat flexible materials such as films and tapes, as well as hard materials such as glass substrates.

Examples of substrates used in the formation of the anisotropic dye film of the present invention include glass, triacetate, acrylic, polyester, polyimide, polyetherimide, polyetheretherketone, polycarbonate, cycloolefin polymer, polyolefin, polyvinyl chloride, triacetyl cellulose, or urethane-based films. In addition, the surface of this substrate may be subjected to an orientation treatment (orientation film) by a known method described in pages 226 to 239 of "Liquid Crystal Handbook" (Maruzen Co., Ltd., published October 30, 2000) in order to control the orientation direction of the dye (rubbing method, method of forming grooves (fine groove structure) on the surface of the orientation film, method using polarized ultraviolet light/polarized laser (photo-orientation method), orientation method by LB film formation, orientation method by oblique deposition of inorganic material, etc.). In particular, orientation treatment by rubbing method and photo-orientation method are preferable. Examples of materials used in the rubbing method include polyvinyl alcohol (PVA), polyimide (PI), epoxy resin, acrylic resin, etc. Materials used in the photoalignment method include polycinnamates, polyamic acid/polyimides, azobenzenes, etc. When an alignment layer is provided, it is believed that the liquid crystal compounds and dyes are aligned due to the influence of the alignment treatment of the alignment layer and the shear force applied to the anisotropic dye film composition during application.

When applying the composition for anisotropic dye film, the method and interval for supplying the composition for anisotropic dye film are not particularly limited. Since the operation of supplying the coating liquid may become complicated and the coating film thickness may vary when the coating liquid is started and stopped, when the anisotropic dye film is thin, it is desirable to apply the composition for anisotropic dye film while continuously supplying it.

The coating speed of the composition for anisotropic dye film is usually 0.001 m/min or more, preferably 0.01 m/min or more, more preferably 0.1 m/min or more, even more preferably 1.0 m/min or more, and particularly preferably 5.0 m/min or more. Also, it is usually 400 m/min or less, preferably 200 m/min or less, more preferably 100 m/min or less, and even more preferably 50 m/min or less. By having the coating speed in the above range, the anisotropy of the anisotropic dye film is obtained, and it tends to be coated uniformly.
The coating temperature of the composition for anisotropic dye film is usually from 0° C. to 100° C., preferably 80° C. or less, and more preferably 60° C. or less.
The humidity during application of the composition for anisotropic dye film is preferably 10% RH or higher and preferably 80% RH or lower.

The anisotropic dye film may be subjected to an insolubilization treatment. Insolubilization refers to a treatment for reducing the solubility of a compound in the anisotropic dye film, thereby controlling the elution of the compound from the anisotropic dye film and increasing the stability of the film.
Specifically, film polymerization or overcoating is preferred from the standpoint of ease of post-processing and durability of the anisotropic dye film.

When polymerizing the film, the film in which the liquid crystal molecules and dye molecules are oriented is polymerized using light, heat, and/or radiation.

When polymerization is carried out using light or radiation, it is preferable to irradiate with active energy rays having a wavelength in the range of 190 to 450 nm.
The light source of the active energy ray having a wavelength of 190 to 450 nm is not particularly limited, and examples thereof include lamp light sources such as xenon lamps, halogen lamps, tungsten lamps, high pressure mercury lamps, ultra-high pressure mercury lamps, metal halide lamps, medium pressure mercury lamps, low pressure mercury lamps, carbon arcs, and fluorescent lamps; and laser light sources such as argon ion lasers, YAG lasers, excimer lasers, nitrogen lasers, helium cadmium lasers, and semiconductor lasers. When using the active energy ray by irradiating it with light of a specific wavelength, an optical filter can also be used. The exposure amount of the active energy ray is preferably 1 to 100,000 J/ ^m2 , and more preferably 10 to 10,000 J/ ^m2 .

When polymerization is carried out using heat, it is preferably carried out within a range of 50 to 200°C, more preferably within a range of 60 to 150°C.
Polymerization may be carried out using light, heat, and/or radiation, but photopolymerization or a combination of photopolymerization and thermal polymerization is preferred because the film formation process takes a short time and requires a simple apparatus.

[Optical elements]
The optical element of the present invention includes the anisotropic dye film of the present invention.
The optical element in the present invention refers to a polarizing element that utilizes the anisotropy of light absorption to obtain linearly polarized light, circularly polarized light, elliptically polarized light, etc., a phase difference element, an element having functions such as refractive anisotropy and conductive anisotropy, etc. These functions can be appropriately adjusted by selecting the anisotropic dye film formation process and the composition containing the substrate and organic compound (dye or transparent material).

The optical element of the present invention is most preferably used as a polarizing element.
The optical element of the present invention can be suitably used for applications such as flexible displays because a polarizing element can be obtained by forming an anisotropic dye film on a substrate by coating or the like.

The optical element may be provided with other layers to maintain or improve the functionality of the anisotropic dye film. For example, layers that have the function of blocking specific wavelengths or layers that have the function of blocking specific substances (e.g., barrier films such as oxygen barrier films and water vapor barrier films) used to improve durability such as light resistance, heat resistance, and water resistance; layers that contain wavelength cut filters or materials that absorb specific wavelengths used to change the color gamut or improve optical properties; etc.

[Polarizing element]
The polarizing element of the present invention may have any other film (layer) as long as it has the anisotropic dye film of the present invention. For example, it can be produced by providing an alignment film on a substrate and forming the anisotropic dye film of the present invention on the surface of the alignment film.
Furthermore, the polarizing element is not limited to an anisotropic dye film, and may be used in combination with an overcoat layer having a function of improving polarization performance, improving mechanical strength, etc., an adhesive layer or antireflection layer, an alignment film, a layer having optical functions such as a function as a retardation film, a function as a brightness enhancing film, a function as a reflective or antireflection film, a function as a semi-transmissive reflective film, a function as a diffusion film, etc. Specifically, the layers having the above-mentioned various functions may be laminated by coating, lamination, etc., and used as a laminate.
These layers can be provided appropriately according to the manufacturing process, characteristics, and functions, and the positions and order of lamination are not particularly limited. For example, each layer may be formed on the anisotropic dye film, or on the opposite side of the substrate on which the anisotropic dye film is provided. Furthermore, each layer may be formed either before or after the anisotropic dye film is formed.

These layers having optical functions can be formed by the following methods.
A layer having a function as a retardation film can be formed by coating or laminating a retardation film on other layers constituting a polarizing element, etc. The retardation film can be formed, for example, by performing a stretching treatment described in JP-A-2-59703, JP-A-4-230704, etc., or a treatment described in JP-A-7-230007, etc.

A layer that functions as a brightness enhancement film can be formed by coating or laminating a brightness enhancement film onto other layers that make up the polarizing element. A brightness enhancement film can be formed, for example, by forming micropores using the methods described in JP-A-2002-169025 and JP-A-2003-29030, or by superimposing two or more cholesteric liquid crystal layers that have different central wavelengths of selective reflection.

A layer having the function of a reflective film or a semi-transparent reflective film can be formed, for example, by coating or laminating a thin metal film obtained by vapor deposition or sputtering onto other layers constituting the polarizing element.
The layer having the function of a diffusion film can be formed, for example, by coating another layer constituting the polarizing element with a resin solution containing fine particles.

A layer that functions as a retardation film or an optical compensation film can be formed by applying liquid crystal compounds such as discotic liquid crystal compounds, nematic liquid crystal compounds, smectic liquid crystal compounds, and cholesteric liquid crystal compounds to other layers that constitute a polarizing element and orienting them. In this case, an orientation film may be provided on the substrate, and the retardation film or optical compensation film may be formed on the surface of the orientation film.

When the anisotropic dye film of the present invention is used as an anisotropic dye film in various display elements such as LCDs and OLEDs, the anisotropic dye film of the present invention may be formed directly on the surface of an electrode substrate constituting these display elements, or a substrate on which the anisotropic dye film of the present invention is formed may be used as a component of these display elements.

The present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples as long as it does not depart from the gist of the present invention.
In the following description, "parts" means "parts by weight".

[Method for identifying liquid crystal phase]
The liquid crystallinity of the obtained anisotropic dye film-forming composition was observed by any one of methods such as differential scanning calorimetry (Seiko Instruments Inc. "DSC220CU"), X-ray structural analysis (Rigaku Corp. "NANO-Viewer"), and a polarizing microscope (Nikon Instech Corp. "Eclipse LV100N POL") equipped with a hot stage (Toyo Corp. "HCS302-LN190"), or a combination of a plurality of methods, and the liquid crystallinity was identified according to the method described on pages 9 to 50 and 117 to 176 of "Liquid Crystal Handbook" (Maruzen Co., Ltd., published on October 30, 2000).

[How to check for haze]
The haze of the obtained liquid crystal film and anisotropic dye film was confirmed by either a method in which a sample was placed on an A4 size paper with printed characters equipped with a backlight and the haze was visually confirmed by three or more persons to determine its superiority or inferiority, or a method in which the haze was measured using a haze meter (Nippon Denshoku Industries Co., Ltd. "NDH5000SP"), or both.

[Measurement of transmittance and dichroic ratio for polarized light along the absorption axis/polarization axis direction of anisotropic dye film]
The dichroism of the obtained anisotropic dye film can be confirmed by holding the absorption axis of a polarizing plate at 0° and 90° to the absorption axis of the anisotropic dye film. If the film is bright and dark at 0° and 90°, it can be determined that the film has dichroism.
The transmittance of the resulting anisotropic dye film for polarized light in the absorption axis/polarization axis direction was measured using a spectrophotometer equipped with a Glan-Thompson polarizer (manufactured by Otsuka Electronics Co., Ltd., product name "RETS-100").
Linearly polarized measurement light was incident on the anisotropic dye film, and the transmittance for polarized light in the absorption axis direction of the anisotropic dye film and the transmittance for polarized light in the polarization axis direction of the anisotropic dye film were measured, and the dichroic ratio (D) was calculated by the following formula.
D = Az/Ay
(Wherein,
Ay=-log(Ty);
Az=-log(Tz);
Tz is the transmittance of the anisotropic dye film for polarized light in the absorption axis direction;
Ty is the transmittance of the anisotropic dye film for polarized light in the direction of the polarization axis.

Specifically, the anisotropic dye film composition was injected in an isotropic phase into a sandwich cell (a polyimide film that had been previously rubbed with a cloth) in which a polyimide alignment film (LX1400, Hitachi Chemical DuPont Microsystems) was formed on a glass substrate, and an anisotropic dye film was obtained by cooling, and the presence or absence of dichroism was confirmed at each temperature.

Claims (12)

A composition for forming an anisotropic dye film, comprising a dichroic dye and a liquid crystal compound,
The composition for forming an anisotropic dye film, wherein the liquid crystal compound comprises a liquid crystal compound represented by formula (1):
R1-A1-Y1-A2-Y2-A3-R2 ... (1)
In formula (1),
R1 and R2 each independently represent a chain organic group having a polymerizable group;
In the chain organic group having a polymerizable group, the sum of the chain lengths of R1 and R2 is 5 or more;
The polymerizable group R1 and R2 each have a chain length of 7 or more;
A1 and A3 each independently represent a partial structure represented by the following formula (2), a divalent organic group, or a single bond:
A2 represents a partial structure represented by the following formula (2) or a group represented by the following formula (3) ;
-Y1- and -Y2- each independently represent a single bond, -C(=O)O-, -OC(=O)-, -C(=S)O-, -OC(=S)-, -C(=O)S-, -SC(=O)-, -CH ₂ CH ₂ -, -CH=CH-, -C(=O)NH-, -NHC(=O)-, -CH ₂ O-, -OCH ₂ -, -CH ₂ S-, or -SCH ₂ -;
One of A1 and A3 is a partial structure represented by the following formula (2) or a divalent organic group:
At least one of A1, A2, and A3 is a partial structure represented by the following formula (2).
-Cy-X2-C≡C-X- ... (2)
In formula (2),
Cy represents a hydrocarbon ring group or a heterocyclic group;
-X- represents -C(=O)O-, -OC(=O)-, -C(=S)O-, -OC(=S)-, -C(=O)S-, -SC(=O)-, -CH ₂ CH ₂ -, -CH=CH-, -C(=O)NH-, -NHC(=O)-, -CH ₂ O-, -OCH ₂ -, -CH ₂ S-, or -SCH ₂ -;
-X2- represents a single bond, -C(=O)O-, -OC(=O)-, -C(=S)O-, -OC(=S)-, -C(=O)S-, -SC(=O)-, -CH ₂ CH ₂ -, -CH=CH-, -C(=O)NH-, -NHC(=O)-, -CH ₂ O-, -OCH ₂ -, -CH ₂ S-, or -SCH ₂ -.
-Q1- ... (3)
In formula (3),
Q1 represents a hydrocarbon ring group or a heterocyclic group;
When the hydrocarbon ring group for Q1 is a non-linked aromatic hydrocarbon ring group, it is a divalent group of a benzene ring or a divalent group of a naphthalene ring. 2. The composition for forming an anisotropic dye film according to claim 1, wherein --X-- is --C(.dbd.O)O--, --OC(.dbd.O)--, --CH ₂ CH ₂ --, --CH ₂ O--, or --OCH ₂ --. The composition for forming an anisotropic dye film according to claim 1 or 2, wherein Cy in formula (2) is a hydrocarbon ring group and -X2- is a single bond. One of A1, A2, and A3 is a partial structure represented by the formula (2), and the other two are each independently a group represented by the formula (3) ,
4. The composition for forming an anisotropic dye film according to claim 1, wherein in said formula (2), Cy is a hydrocarbon ring group, and --X2-- is a single bond. The composition for forming an anisotropic dye film according to any one of claims 1 to 4, wherein Cy in formula (2) is a 1,4-phenylene group or a cyclohexane-1,4-diyl group. The composition for forming an anisotropic dye film according to any one of claims 1 to 5, wherein Cy in formula (2) is a 1,4-phenylene group. The composition for forming an anisotropic dye film according to any one of claims 1 to 6, wherein the chain organic group having a polymerizable group is a -( _CH2 ) _n -polymerizable group or a -O-( _CH2 ) _n-1 -polymerizable group, where n is an integer. _-Y1- and -Y2- each independently represent a single bond, -C(=O)O-, -OC(=O)-, _-CH2CH2- , _-CH2O- or _-OCH2- ;
8. The composition for forming an anisotropic dye film according to claim 1, wherein --X-- is --C(.dbd.O)O--, --OC(.dbd.O)--, --CH ₂ CH ₂ --, --CH ₂ O-- or --OCH ₂ --. The composition for forming an anisotropic dye film according to any one of claims 1 to 8, wherein one of A1 and A3 is a cyclohexane-1,4-diyl group. The composition for forming an anisotropic dye film according to any one of claims 1 to 9, wherein one of A1 and A3 is a partial structure represented by formula (2) and the other is a cyclohexane-1,4-diyl group. An anisotropic dye film formed using the composition for forming an anisotropic dye film according to any one of claims 1 to 10. An optical element comprising the anisotropic dye film according to claim 11.