Liquid crystal composition, photocured product, and light control element

Abstract

A liquid crystal composition containing a dichroic dye (A), a liquid crystal compound (B), a photocurable compound (C), and a photopolymerization initiator (D), wherein the dichroic dye (A) contains at least one selected from a compound (A1) represented by general formula (1) and a compound (A2) having a molecular weight of 540 g / mol or less and represented by general formula (2). (In formula (1), X1 to X4 are each independently -S-Ar or -OH, and Ar represents an aryl group. Ar may have a linear or branched alkyl group, a haloalkyl group, an alkoxy group, a cycloalkyl group, an aryl group, a heterocyclic group, or a halogen atom as a substituent.　Two of X1 to X4 are -S-Ar and the remaining two are -OH. R1 to R4 each independently represent a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, a phenyl group which may have a substituent, or a phenoxy group which may have a substituent.) (In formula (2), R11 to R15 each independently represent a hydrogen atom, an alkyl group which may have a substituent, or an alkoxy group which may have a substituent. R21 to R25 each independently represent a hydrogen atom, an alkyl group which may have a substituent, or an alkoxy group which may have a substituent.)

Description

Liquid crystal composition, photocured product, light-adjusting element

[0001] The present invention relates to a liquid crystal composition, a photocured product of the liquid crystal composition, and a light-adjusting device including the photocured product.

[0002] In recent years, liquid crystal light control elements have been put to practical use as light control shutters for the purpose of improving design, protecting privacy, etc., in windows, doors, partitions, etc. of vehicles such as trains and automobiles, and buildings such as business buildings and hospitals. Many of these prior art technologies use polymer-dispersed liquid crystal elements, so-called PDLC (Polymer Dispersed Liquid Crystals) type (Patent Document 1).

[0003] This method involves electrically switching between a transparent and a scattering state, but has issues such as limited change in total light transmittance. Therefore, guest-host liquid crystal dimming devices, in which a dichroic dye is added to the liquid crystal material, have been investigated to improve brightness and design. Liquid crystal devices using chiral nematic liquid crystals as the host liquid crystal material in guest-host liquid crystal materials have attracted attention because of their advantages, such as a wider dynamic range when electrically switching between light and dark states than devices without a dichroic dye and the elimination of polarizing plates (Patent Document 2). Patent Document 3 describes a mixed composition of a photopolymerizable monomer and liquid crystal, in which a phase-separated structure of a polymer (the polymerization product of the photopolymerizable monomer) and liquid crystal is formed by photopolymerization-induced phase separation, and a liquid crystal-polymer composite film is produced by photopolymerization-induced phase separation.

[0004] Japanese Patent Laid-Open No. 4-42213 Japanese Patent Laid-Open No. 2019-85581 Japanese Patent Laid-Open No. 2011-190314

[0005] In order to obtain a wide dynamic range in a liquid crystal composition containing a dichroic dye, it is necessary to enhance the light-blocking property of the dichroic dye, but the higher the light-blocking property of the dichroic dye, the more likely curing inhibition occurs. That is, an object of the present invention is to provide a liquid crystal composition and a light-controlling element that have excellent curability, a wide dynamic range, and high contrast.

[0006] As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by a liquid crystal composition containing a dichroic dye (A), a liquid crystal compound (B), a photocurable compound (C), and a photopolymerization initiator (D), wherein the dichroic dye (A) contains a specific dye, and have thus arrived at the present invention. That is, the present invention includes the following aspects.

[0007] [1] A liquid crystal composition comprising a dichroic dye (A), a liquid crystal compound (B), a photocurable compound (C), and a photopolymerization initiator (D), wherein the dichroic dye (A) comprises at least one selected from a compound (A1) represented by the following general formula (1) and a compound (A2) represented by the following general formula (2) having a molecular weight of 540 g / mol or less:

[0008]

[0009] (In formula (1), X １ ~X ４ are each independently -S-Ar or -OH, and Ar represents an aryl group. Ar may have a linear or branched alkyl group, a haloalkyl group, an alkoxy group, a cycloalkyl group, an aryl group, a heterocyclic group, or a halogen atom as a substituent. However, X １ ~X ４ Of these, two are -S-Ar and two are -OH. １ ~R ４ each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkoxy group, an optionally substituted phenyl group, or an optionally substituted phenoxy group.

[0010]

[0011] (In formula (2), R １１ ~R １５ R each independently represents a hydrogen atom, an alkyl group which may have a substituent, or an alkoxy group which may have a substituent. ２１ ~R ２５ each independently represents a hydrogen atom, an alkyl group which may have a substituent, or an alkoxy group which may have a substituent.

[0012] [2] The liquid crystal composition according to the above [1], wherein the compound (A1) is a compound represented by the following general formula (1-1) or the following general formula (1-2):

[0013]

[0014]

[0015] (In formulas (1-1) and (1-2), Ar １ ~Ar ４ each independently represents an aryl group which may have an alkyl substituent; R １ ~R ４ each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkoxy group, an optionally substituted phenyl group, or an optionally substituted phenoxy group.

[0016] [3] In the general formula (2), R １１ ~R １５ , and R ２１ ~R ２５are each independently a hydrogen atom or an alkyl group having 3 or less carbon atoms. [4] The liquid crystal composition according to any one of [1] to [3] above, wherein the compound (A1) or the compound (A2) has an OD value of 30 or more. [5] The liquid crystal composition according to any one of [1] to [4] above, wherein the compound (A1) or the compound (A2) has an OD value of 48 or more. [6] The liquid crystal composition according to any one of [1] to [5] above, wherein the dichroic dye (A) contains at least three dyes. [7] The liquid crystal composition according to [6] above, wherein at least one of the three dyes has an OD value of 25 or more. [8] The liquid crystal composition according to any one of [1] to [7] above, wherein the dichroic dye (A) contains three or more dyes having an absorption maximum wavelength in a wavelength region of 480 nm or more. [9] The liquid crystal composition according to the above [8], wherein, when the dyes having an absorption maximum in the wavelength region of 480 nm or more are ranked in order of shortest absorption maximum wavelength as dye (α-1), dye (α-2), and dye (α-3), the OD value of the dye (α-2) is 25 or more.

[10] The liquid crystal composition according to the above [8] or [9], wherein, when the dyes having an absorption maximum in the wavelength region of 480 nm or more are ranked in order of shortest absorption maximum wavelength as dye (α-1), dye (α-2), and dye (α-3), the OD values ​​of the dye (α-2) and the dye (α-3) are 25 or more.

[11] When the dyes having an absorption maximum wavelength in the wavelength region of 480 nm or more are designated as dye (α-1), dye (α-2), and dye (α-3) in order of shortest absorption maximum wavelength, the absorbance S of each of the dyes (α-1), (α-2), and (α-3) measured under the conditions of a chloroform solvent, a concentration of 1 mg / 100 mL, and an optical path length of 1 cm is α－１ , S α－２ , and S α－３ and a standard relative luminosity curve V satisfy the relationship of the following mathematical formula (1):

[0017]

[0018] (In formula (1), S α－１ (λ) is the spectral absorption spectrum of the dye (α-1), S α－２(λ) is the spectral absorption spectrum of the dye (α-2), S α－３ (λ) is the spectral absorption spectrum of the dye (α-3), and V(λ) is the standard luminous efficiency curve. λ is the measurement wavelength (nm), which is 380 to 800.

[0019]

[12] When the dyes having an absorption maximum wavelength in the wavelength region of 480 nm or more are designated as dye (α-1), dye (α-2), and dye (α-3) in order of shortest absorption maximum wavelength, the absorbance of the dye (α-2) measured under the conditions of a chloroform solvent, a concentration of 1 mg / 100 mL, and an optical path length of 1 cm is S α－２ and a standard relative luminosity curve V satisfy the following mathematical formula (2):

[0020] (In formula (2), S α－２ (λ) is the spectral absorption spectrum of the dye (α-2), and V(λ) is the standard luminous efficiency curve. λ is the measurement wavelength (nm), which is 380 to 800.

[0021]

[13] When the dyes having an absorption maximum wavelength in the wavelength region of 480 nm or more are designated as dye (α-1), dye (α-2), and dye (α-3) in order of shortest absorption maximum wavelength, the absorbance of the dye (α-3) measured under the conditions of a chloroform solvent, a concentration of 1 mg / 100 mL, and an optical path length of 1 cm is S α－３ and a standard relative luminosity curve V satisfy the following mathematical formula (3):

[0022]

[0023] (In formula (3), S α－３ (λ) is the spectral absorption spectrum of the dye (α-3), and V(λ) is the standard luminous efficiency curve. λ is the measurement wavelength (nm), which is 380 to 800.

[0024]

[14] The liquid crystal composition according to any one of the above [1] to

[13] , wherein the sum of the contents of the compound (A1) and the compound (A2) with respect to the total weight of the dichroic dye (A) is less than 70% by mass.

[15] The liquid crystal composition according to any one of the above [1] to

[14] , wherein a guest-host liquid crystal composition comprising the dichroic dye (A) and the liquid crystal compound (B) is filled into an antiparallel aligned glass cell, and the ratio (T⊥ / T / / ) of the visible light transmittance (T / / ) measured by irradiating with light polarized parallel to the alignment direction to the visible light transmittance (T⊥) measured by irradiating with light polarized perpendicular to the alignment direction is 8.0 or more.

[16] The liquid crystal composition according to any one of the above [1] to

[15] , wherein the photocurable compound (C) comprises a mono(meth)acrylate compound and a polyfunctional (meth)acrylate compound.

[17] The liquid crystal composition according to any one of [1] to

[16] above, wherein the photocurable compound (C) comprises a urethane (meth)acrylate compound.

[18] Use of the liquid crystal composition according to any one of [1] to

[17] above as a light control element.

[19] A photocured product obtained by photocuring the liquid crystal composition according to any one of [1] to

[17] above.

[20] A light control element comprising a pair of substrates arranged opposite each other, at least one of which is a transparent substrate having a transparent electrode, and a layer of the photocured product according to

[19] above sandwiched between them.

[21] An in-vehicle member comprising the light control element according to

[20] above.

[22] A building member comprising the light control element according to

[20] above.

[23] A wearable device comprising the light control element according to

[20] above.

[24] A light control window comprising the light control element according to

[20] above.

[25] A sunroof comprising the light control element according to

[20] above.

[0025] According to the present invention, it is possible to provide a liquid crystal composition and a light-adjusting element that have excellent curability, a wide dynamic range, and a high contrast.

[0026] FIG. 1 is an image of the light-control element obtained in Example 1-1 photographed with an optical microscope. FIG. 2 is an image obtained by binarizing the image of FIG. 1 so that the liquid crystal portion appears black and the other portions appear white. FIG. 3 is an image of the light-control element obtained in Example 1-2 photographed with an optical microscope under the same conditions as in Example 1. FIG. 4 is an image of the image of FIG. 3 photographed with a binarization process so that the liquid crystal portion appears black and the other portions appear white. FIG. 5 is an image of the light-control element obtained in Comparative Example 1-1 photographed with an optical microscope under the same conditions as in Example 1. FIG. 6 is an image of the image of FIG. 5 photographed with a binarization process so that the liquid crystal portion appears black and the other portions appear white. FIG. 7 is an image of the light-control element obtained in Comparative Example 2 photographed with an optical microscope under the same conditions as in Example 1. FIG. 8 is an image of the image of FIG. 7 photographed with a binarization process so that the liquid crystal portion appears black and the other portions appear white.

[0027] The present invention will be described below. The following description of the embodiments shown in the drawings is an example, and the present invention is not limited to the configurations shown in the drawings. In this specification, when "X to Y" (X and Y are arbitrary numbers) is used, it means "X or more and Y or less" unless otherwise specified, and also includes the meaning of "preferably larger than X" or "preferably smaller than Y." Furthermore, when "X or more" (X is an arbitrary number) or "Y or less" (Y is an arbitrary number) is used, it also includes the meaning of "preferably larger than X" or "preferably smaller than Y."

[0028] <Liquid Crystal Composition> The liquid crystal composition of the present invention (hereinafter may be referred to as "the present liquid crystal composition") is a liquid crystal composition containing a dichroic dye (A), a liquid crystal compound (B), a photocurable compound (C), and a photopolymerization initiator (D), in which the dichroic dye (A) contains at least one selected from a compound (A1) represented by the following general formula (1) and a compound (A2) represented by the following general formula (2) having a molecular weight of 540 g / mol or less:

[0029]

[0030] In formula (1), X １ ~X ４are each independently -S-Ar or -OH, and Ar represents an aryl group. Ar may have a linear or branched alkyl group, a haloalkyl group, an alkoxy group, a cycloalkyl group, an aryl group, a heterocyclic group, or a halogen atom as a substituent. However, X １ ~X ４ Of these, two are -S-Ar and two are -OH. １ ~R ４ each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkoxy group, an optionally substituted phenyl group, or an optionally substituted phenoxy group.

[0031]

[0032] In formula (2), R １１ ~R １５ R each independently represents a hydrogen atom, an alkyl group which may have a substituent, or an alkoxy group which may have a substituent. ２１ ~R ２５ each independently represents a hydrogen atom, an alkyl group which may have a substituent, or an alkoxy group which may have a substituent.

[0033] [Dichroic Dye (A)] The present liquid crystal composition contains, as the dichroic dye (A), at least one selected from the compound (A1) represented by the above general formula (1) and the compound (A2) represented by the above general formula (2).

[0034] (Compound (A1)) The compound (A1) is a compound represented by the following general formula (1).

[0035]

[0036] In formula (1), X １ ~X ４ are each independently -S-Ar or -OH, and Ar represents an aryl group. Ar may have a linear or branched alkyl group, a haloalkyl group, an alkoxy group, a cycloalkyl group, an aryl group, a heterocyclic group, or a halogen atom as a substituent. However, X １ ~X ４ Of these, two are -S-Ar and two are -OH. １~R ４ each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkoxy group, an optionally substituted phenyl group, or an optionally substituted phenoxy group.

[0037] In formula (1), R １ ~R ４ each independently represents a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, a phenyl group which may have a substituent, or a phenoxy group which may have a substituent. As the alkyl group, a linear or branched alkyl group having 1 to 20 carbon atoms is preferred, and a linear or branched alkyl group having 1 to 10 carbon atoms is more preferred. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group, a neo-pentyl group, a t-pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a 3,3,5-trimethylhexyl group, a decyl group, an undecyl group, and a dodecyl group. The alkoxy group is preferably a linear or branched alkoxy group having 1 to 5 carbon atoms, and specific examples thereof include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, an iso-butoxy group, a sec-butoxy group, a t-butoxy group, an n-pentyloxy group, an iso-pentyloxy group, a sec-pentyloxy group, a neo-pentyloxy group, and a t-pentyloxy group. Furthermore, as the substituent of the phenyl group and the phenoxy group, a linear or branched alkyl group having 1 to 10 carbon atoms is preferable, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group, a neo-pentyl group, a t-pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a cyclopentyl group, a cyclohexyl group, a 2-ethylhexyl group, a 2-propylhexyl group, and a 2-butylhexyl group.

[0038] R １ ~R４ Among these, a structure in which at least two are hydrogen atoms is preferred, and the remaining two are preferably an alkyl group which may have a substituent, an alkoxy group which may have a substituent, a phenyl group which may have a substituent, a phenoxy group which may have a substituent, or a hydrogen atom, more preferably an alkyl group which may have a substituent, a phenoxy group which may have a substituent, or a hydrogen atom, and even more preferably an alkyl group which may have a substituent or a hydrogen atom.

[0039] In formula (1), X １ ~X ４are each independently -S-Ar or -OH, and Ar represents an aryl group. Ar may have a linear or branched alkyl group, a haloalkyl group, an alkoxy group, a cycloalkyl group, an aryl group, a heterocyclic group, or a halogen atom as a substituent. Examples of the aryl group include hydrocarbon aryl groups such as a phenyl group or a naphthyl group; and heteroaryl groups such as a pyridyl group, a thienyl group, a thiazolyl group, a thiadiazolyl group, a benzothiazolyl group, and a quinolyl group. Hydrocarbon aryl groups are preferred, and a phenyl group is more preferred. The substituent on the aryl group may be a linear or branched alkyl group, a haloalkyl group, an alkoxy group, a cycloalkyl group, an aryl group, a heterocyclic group, or a halogen atom, and examples thereof include linear or branched alkyl groups having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group, a neo-pentyl group, a t-pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a cyclopentyl group, a cyclohexyl group, a 2-ethylhexyl group, a 2-propylhexyl group, and a 2-butylhexyl group. haloalkyl groups having 1 to 5 carbon atoms such as trifluoromethyl and difluoromethyl groups; alkoxy groups having 1 to 10 carbon atoms such as methoxy, ethoxy, benzyloxy, difluoromethoxy and trifluoromethoxy groups; cycloalkyl groups such as adamantyl, cyclopentyl, cyclohexyl, cyclooctyl and isobornyl groups; aryl groups such as phenyl and naphthyl groups; heterocyclic groups such as pyridyl, thienyl, thiazolyl, thiadiazolyl, benzothiazolyl and quinolyl groups; and halogen atoms such as fluorine, chlorine, bromine and iodine atoms, among which linear or branched alkyl groups having 1 to 10 carbon atoms are preferred.

[0040] X １ ~X ４ In one embodiment of the liquid crystal composition of the present invention, the dichroic dye (A) is a compound represented by the following general formula (1-1) or (1-2):

[0041]

[0042]

[0043] In formulas (1-1) and (1-2), Ar １ ~Ar ４ each independently represents an aryl group which may have a substituent, R １ ~R ４ each independently represents a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, a phenyl group which may have a substituent, or a phenoxy group which may have a substituent. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group, a neo-pentyl group, a t-pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a 3,3,5-trimethylhexyl group, a decyl group, an undecyl group, and a dodecyl group. A linear or branched alkyl group having 1 to 20 carbon atoms is preferred, and a linear or branched alkyl group having 1 to 10 carbon atoms is more preferred. Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, an iso-butoxy group, a sec-butoxy group, a t-butoxy group, an n-pentyloxy group, an iso-pentyloxy group, a sec-pentyloxy group, a neo-pentyloxy group, and a t-pentyloxy group. A linear or branched alkoxy group having 1 to 10 carbon atoms is preferred, and a linear or branched alkoxy group having 1 to 5 carbon atoms is more preferred. Furthermore, examples of the substituent on the phenyl group and the phenoxy group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group, a neo-pentyl group, a t-pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a cyclopentyl group, a cyclohexyl group, a 2-ethylhexyl group, a 2-propylhexyl group, and a 2-butylhexyl group, among which a linear or branched alkyl group having 1 to 10 carbon atoms is preferred.

[0044] R １ ~R ４ Among these, a structure in which at least two are hydrogen atoms is preferred, and the remaining two are preferably an alkyl group which may have a substituent, an alkoxy group which may have a substituent, a phenyl group which may have a substituent, a phenoxy group which may have a substituent, or a hydrogen atom, and more preferably an alkyl group which may have a substituent or a hydrogen atom. １ ~R ４ When two of the groups are hydrogen atoms and two are alkyl groups which may have a substituent, it is more preferable that the two hydrogen atoms are not adjacent to each other, and it is even more preferable that each hydrogen atom is adjacent to -S-Ar. １ and R ３ is a hydrogen atom, and R ２ and R ４ is preferably an alkyl group, and in formula (1-2), R ２ and R ３ is a hydrogen atom, and R １ and R ４ is preferably an alkyl group.

[0045] Ar １ ~Ar ４Examples of the aryl group represented by the formula (I) include hydrocarbon aryl groups such as a phenyl group and a naphthyl group; and heteroaryl groups such as a pyridyl group, a thienyl group, a thiazolyl group, a thiadiazolyl group, a benzothiazolyl group, and a quinolyl group. As the aryl group, a hydrocarbon aryl group is preferable, and a phenyl group is more preferable. Examples of the substituent on the aryl group include linear or branched alkyl groups having 1 to 10 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl, t-pentyl, hexyl, heptyl, octyl, nonyl, decyl, cyclopentyl, cyclohexyl, 2-ethylhexyl, 2-propylhexyl, and 2-butylhexyl groups; and linear or branched alkyl groups having 1 to 5 carbon atoms, such as trifluoromethyl and difluoromethyl groups. alkoxy groups having 1 to 10 carbon atoms, such as a methoxy group, ethoxy group, benzyloxy group, difluoromethoxy group, and trifluoromethoxy group; cycloalkyl groups, such as an adamantyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, and an isobornyl group; aryl groups, such as a phenyl group and a naphthyl group; heterocyclic groups, such as a pyridyl group, a thienyl group, a thiazolyl group, a thiadiazolyl group, a benzothiazolyl group, and a quinolyl group; and halogen atoms, such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, among which a linear or branched alkyl group having 1 to 10 carbon atoms is preferred.

[0046] Among these, the compound represented by general formula (1-1) is preferred from the viewpoint of excellent curability and light resistance. Among these, the violet colorant compounds represented by formulas (a2-1) to (a2-5) described below are further preferred.

[0047] Moreover, the compound represented by the general formula (1-2) is preferred from the viewpoint of excellent solubility.

[0048] The OD value of compound (A1) is preferably 25 or more, more preferably 30 or more, and even more preferably 32 or more. When the OD value of compound (A1) is within the above range, efficient coloring is possible with a small amount added, making it easier to obtain a light-modulating element with excellent curability and contrast. In the present invention, the OD (Optical Density) value of the dichroic dye can be obtained by dissolving the dichroic dye in chloroform to prepare a 1 mg / 100 mL dye solution, placing the prepared dye solution in a measurement cell with an optical path length of 1 cm, measuring the light absorption spectrum at wavelengths of 280 to 800 nm using a spectrophotometer (e.g., Hitachi High-Technologies Corporation, U-4100), reading the maximum absorbance (Absmax) from the obtained absorbance curve, and calculating the ratio (Absmax / c) of the maximum absorbance to the concentration (c (mg / ml)) of the dye solution.

[0049] When the liquid crystal composition contains compound (A1) as the dichroic dye (A), the content of compound (A1) is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more, based on 100% by mass of the nonvolatile content of the liquid crystal composition. The upper limit is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. When the content is equal to or greater than the lower limit, the light-adjusting element tends to exhibit greater light absorption in the colored state and a smaller amount of transmitted light. When the content is equal to or less than the upper limit, separation or precipitation of the dichroic dye is less likely to occur, and the reliability of the liquid crystal element tends to be improved. Compound (A1) has the property of exhibiting a sufficient coloring effect even when used in small amounts. This allows the content of the dye compound to be reduced. By reducing the content of the dye compound, the content of the photocurable component can be relatively increased. By increasing the content of the photocurable component, the effects of polymerization inhibition can be suppressed, resulting in a light-adjusting element with excellent reliability.

[0050] (Compound (A2)) The compound (A2) is a compound represented by the following general formula (2) and has a molecular weight of 540 g / mol or less.

[0051]

[0052] In formula (2), R １１ ~R １５ and R ２１ ~R ２５ each independently represents a hydrogen atom, an alkyl group which may have a substituent, or an alkoxy group which may have a substituent. When the molecular weight of compound (A2) is 540 g / mol or less, the dichroic dye (A) exhibits a high OD value and can be efficiently colored with a small amount added, making it possible to obtain a light-controlling element which is less susceptible to curing inhibition and has excellent curability and contrast. Furthermore, from the viewpoint of efficiently coloring with a small amount added, the molecular weight of compound (A2) is preferably 530 g / mol or less, more preferably 520 g / mol or less, even more preferably 510 g / mol or less, and particularly preferably 500 g / mol or less. The lower limit is usually 450 g / mol.

[0053] The alkyl group in the general formula (2) is preferably a linear or branched alkyl group having 1 to 6 carbon atoms, and from the viewpoint of obtaining a high OD value, a linear or branched alkyl group having 1 to 3 carbon atoms is more preferable. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group, a neo-pentyl group, a t-pentyl group, a hexyl group, an isohexyl group, and a cyclohexyl group. Of these, from the viewpoint above, a methyl group, an ethyl group, an n-propyl group, and an isopropyl group are preferable, and a methyl group is more preferable.

[0054] The alkoxy group in the general formula (2) is preferably a linear or branched alkoxy group having 1 to 5 carbon atoms, and specific examples thereof include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, an iso-butoxy group, a sec-butoxy group, a t-butoxy group, an n-pentyloxy group, an iso-pentyloxy group, a sec-pentyloxy group, a neo-pentyloxy group, a t-pentyloxy group, etc. Of these, a methoxy group is more preferred.

[0055] Among the compounds (A2), particularly preferred are the blue dye compounds represented by (a4-1) and (a4-2) described below.

[0056] The compound (A2) preferably has an OD value of 48 or more, more preferably 50 or more, and even more preferably 52 or more. When the OD value of the compound (A2) is within the above range, efficient coloring can be achieved with a small amount added, making it easy to obtain a light-controlling element with excellent curability and contrast. There is no particular upper limit, and a higher upper limit is preferable, but it can be, for example, 500 or less, preferably 300 or less, and more preferably 100 or less.

[0057] The compound (A2) preferably has a visual absorbance calculated by the following mathematical formula (I) of 28% or more, more preferably 29% or more, and even more preferably 30% or more. When the visual absorbance of the compound (A1) is equal to or greater than the above-mentioned lower limit, efficient coloring can be achieved with a small amount added, and a light-controlling element having excellent curability and contrast can be easily obtained. The higher the visual absorbance, the better. There is no particular restriction on the upper limit, and it is usually 100% or less, preferably 95% or less, and more preferably 90% or less.

[0058] (In formula (I), S(λ) is the spectral absorption spectrum of the dye (A2), and V(λ) is the standard luminous efficiency curve. λ is the measurement wavelength (nm) and is 380 to 800.)

[0059] The standard relative luminous efficiency in the present invention is a function expressed by V(λ) in "relative luminous efficiency" defined in JIS Z 8105:2022 under photopic conditions, and has a maximum value of 1 at a wavelength λ=555 nm. The luminous absorbance can be determined by the method described in the examples.

[0060] When the liquid crystal composition contains compound (A2) as the dichroic dye (A), the content of compound (A2) is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.3% by mass or more, based on 100% by mass of the nonvolatile content of the liquid crystal composition. The upper limit is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. When the content is equal to or greater than the lower limit, the light-adjusting element tends to exhibit greater light absorption in the colored state and a smaller amount of transmitted light. When the content is equal to or less than the upper limit, separation or precipitation of the dichroic dye is less likely to occur, and the reliability of the liquid crystal element tends to be improved. Compound (A2) has the property of exhibiting a sufficient coloring effect even when used in small amounts. This allows the content of the dye compound to be reduced. By reducing the content of the dye compound, the content of the photocurable component can be relatively increased. By increasing the content of the photocurable component, the effects of polymerization inhibition can be suppressed, resulting in a light-adjusting element with excellent reliability.

[0061] The liquid crystal composition may further contain a dye compound other than Compound (A1) and Compound (A2) as the dichroic dye (A). Specific examples include azo dyes, anthraquinone dyes, naphthoquinone dyes, perylene dyes, quinophthalone dyes, tetrazine dyes, and benzothiadiazole dyes. Among these, anthraquinone dyes other than Compound (A1) and Compound (A2) are preferred because they tend to have a large absorption coefficient, high solubility in the liquid crystal component, and high light resistance. Examples of dyes other than Compound (A1) and Compound (A2) include Compound (a) represented by General Formula (3) described below, and dyes such as those described in "Liquid Crystal Device Handbook," edited by Committee 142 of the Japan Society for the Promotion of Science, Japan Industrial Newspaper Co., Ltd. (1989), pages 192 to 196 and 724 to 730, or mixtures thereof, within a range that does not impair the effects of the present invention.

[0062] Suitable examples of the dye other than the compounds (A1) and (A2) include, for example, a magenta dye represented by the compound (a1), a violet dye represented by the compound (a3), and a yellow dye represented by the compound (a5), which will be described later.

[0063] The liquid crystal composition preferably contains at least three types of dyes as the dichroic dye (A). The dichroic dye (A) used in the present invention preferably contains at least three types of dyes having different absorption spectra, and at least one of these dyes preferably has an OD (optical density) value of 25 or more. The absorption spectrum of the dye can be confirmed by dissolving the dye in chloroform to prepare a 1 mg / 100 mL dye solution, placing the prepared dye solution in a measurement cell with an optical path length of 1 cm, and using a spectrophotometer (e.g., U-4100 manufactured by Hitachi High-Technologies Corporation). The OD value of the dye can be obtained by measuring the absorption spectrum at wavelengths of 380 to 800 nm, reading the maximum absorbance value (Absmax) from the obtained absorbance curve, and calculating the ratio (Absmax / c) of the maximum absorbance value to the concentration (c (mg / mL)) of the dye solution.

[0064] Of the at least three dyes contained in the dichroic dye (A), at least one has an OD value of preferably 25 or more, more preferably 30 or more, even more preferably 32 or more, and even more preferably 35 or more. When the OD value of at least one of the dichroic dyes (A) is within the above range, efficient coloring can be achieved with a small amount added, and a light-controlling element excellent in curability and contrast can be easily obtained.

[0065] The liquid crystal composition preferably contains three or more dyes having an absorption maximum wavelength in the wavelength region of 480 nm or more, and more preferably contains three or more dyes having an absorption maximum wavelength of 490 nm or more. Furthermore, the absorption maximum wavelength of the dyes is preferably 645 nm or less, and more preferably 635 nm or less. By containing three or more dyes having absorption maximum wavelengths satisfying the above range, absorption in a region with high luminosity can be achieved, and in particular, transmittance during the off state can be reduced.

[0066] The present liquid crystal composition contains, as the dichroic dye (A), three dyes, dye (α-1), dye (α-2), and dye (α-3), in order of decreasing maximum absorption wavelength. The maximum absorption wavelengths of the dyes (α-1), (α-2), and (α-3) are preferably 480 nm or longer, more preferably 490 nm or longer. Meanwhile, the maximum absorption wavelengths of the dyes (α-1), (α-2), and (α-3) are preferably 645 nm or shorter, more preferably 635 nm or shorter. When the maximum absorption wavelengths of the dyes (α-1), (α-2), and (α-3) satisfy the above relationship, absorption in a region with high luminosity can be achieved, thereby enabling a reduction in transmittance, particularly in the OFF state. The present liquid crystal composition may contain a dye whose maximum absorption wavelength is below the above-mentioned lower limit. When a dye having an absorption maximum wavelength less than the above-mentioned lower limit is included, among the dyes having an absorption maximum wavelength equal to or greater than the above-mentioned lower limit, the dyes are designated as dye (α-1), dye (α-2), and dye (α-3) in order of shortest absorption maximum wavelength.

[0067] The difference in absorption maximum wavelength between the dye (α-1) and the dye (α-2), and the difference in absorption maximum wavelength between the dye (α-2) and the dye (α-3) are each preferably 40 to 60 nm. The difference in absorption maximum wavelength between the dye (α-1) and the dye (α-3) is preferably 100 to 120 nm. When the differences in absorption maximum wavelength between the dye (α-1), the dye (α-2), and the dye (α-3) satisfy the above relationship, a region with high luminosity can be absorbed, and the transmittance can be reduced, particularly when the light is off.

[0068] The liquid crystal composition contains three or more dyes having an absorption maximum in a wavelength region of 480 nm or more. When the dyes having an absorption maximum in a wavelength region of 480 nm or more are designated, in order of shortest absorption maximum wavelength, as dye (α-1), dye (α-2), and dye (α-3), the OD value of (α-2) is preferably 25 or more, more preferably 30 or more, even more preferably 32 or more, even more preferably 40 or more, and particularly preferably 48 or more. There is no particular upper limit, and a higher value is preferable; however, the OD value may be, for example, 500 or less, preferably 300 or less, and more preferably 100 or less. When the OD value of dye (α-2) is within the above range, it is possible to absorb light in a region with high luminosity, and it is possible to reduce the transmittance, particularly when the light is off.

[0069] The OD value of the dye (α-2) is preferably greater than the OD value of the dye (α-1), and the difference is preferably 2 or more, more preferably 4 or more, even more preferably 6 or more, and particularly preferably 8 or more. The upper limit is preferably 20 or less, more preferably 18 or less, and even more preferably 16 or less. The ratio of the OD value of the dye (α-2) to the OD value of the dye (α-1) is preferably 1.1 to 3.0, more preferably 1.2 to 2.5, and even more preferably 1.3 to 2.0. When the OD values ​​of the dye (α-1) and the dye (α-2) satisfy the above relationship, a dye mixture that efficiently absorbs in a high luminosity range can be obtained with a small dye content. The lower the content of the dye compound, the greater the relative content of the photocurable component can be, which tends to facilitate the production of a liquid crystal composition with excellent curability.

[0070] The present liquid crystal composition contains, as the dichroic dye (A), three or more dyes having an absorption maximum wavelength in a wavelength region of 480 nm or more, and when the dyes are classified in order of shortest absorption maximum wavelength as dye (α-1), dye (α-2), and dye (α-3), the OD values ​​of the dye (α-2) and dye (α-3) are preferably 25 or more, more preferably 30 or more, and even more preferably 32 or more. There is no particular upper limit, and a higher upper limit is preferable, but the OD values ​​may be, for example, 500 or less, preferably 300 or less, and more preferably 100 or less. When the OD values ​​of the dye (α-2) and dye (α-3) are within the above range, absorption in a region with high luminosity can be achieved, and it is possible to reduce the transmittance, particularly when the dye is off.

[0071] The OD value of the dye (α-3) is preferably greater than the OD value of the dye (α-2), and the difference is preferably 2 or more, more preferably 4 or more, even more preferably 6 or more, and particularly preferably 8 or more. The upper limit is preferably 40 or less, more preferably 35 or less, and even more preferably 30 or less. The ratio of the OD value of the dye (α-3) to the OD value of the dye (α-2) is preferably 1.1 to 3.0, more preferably 1.2 to 2.5, and even more preferably 1.3 to 2.0. When the OD values ​​of the dye (α-2) and the dye (α-3) satisfy the above relationship, a dye mixture that efficiently absorbs in a region with high luminosity can be obtained with a small dye content. The lower the content of the dye compound, the greater the relative content of the photocurable component can be, and therefore, a liquid crystal composition with excellent curability tends to be obtained.

[0072] The liquid crystal composition contains, as the dichroic dye (A), three or more dyes having an absorption maximum wavelength in a wavelength region of 480 nm or more, and the dyes are designated as dye (α-1), dye (α-2), and dye (α-3) in order of shortest absorption maximum wavelength. The absorbances of the dye (α-1), dye (α-2), and dye (α-3), measured under the conditions of a chloroform solvent, a concentration of 1 mg / 100 mL, and an optical path length of 1 cm, are respectively S α－１ , S α－２ , and S α－３ When S is set, it is preferable that the absorbance and the standard relative luminous efficiency curve V satisfy the relationship of the following mathematical formula (1): α－１ , S α－２ , and Sα－３ can be measured using the spectrophotometer described above.

[0073]

[0074] In formula (1), S α－１ (λ) is the spectral absorption spectrum of the dye (α-1), S α－２ (λ) is the spectral absorption spectrum of the dye (α-2), S α－３ (λ) is the spectral absorption spectrum of the dye (α-3), V(λ) is the standard luminous efficiency curve, and λ is the measurement wavelength (nm) and is 380 to 800.

[0075] The standard relative luminous efficiency in the present invention is a function expressed by V(λ) in the "relative luminous efficiency" defined in JIS Z 8105:2022 under photopic conditions, and has a maximum value of 1 at a wavelength λ=555 nm.

[0076] The present liquid crystal composition preferably contains, as the dichroic dye (A), three or more dyes having an absorption maximum wavelength in a wavelength region of 480 nm or more, and includes the three dyes, dye (α-1), dye (α-2), and dye (α-3), in order of shortest absorption maximum wavelength, and the dye (α-2) preferably satisfies the following mathematical formula (2). The following mathematical formula (2) represents the visual absorbance (%) of the dye (α-2). The lower limit of the formula (2) is 15%, and more preferably 20%. The upper limit is not particularly limited, but is usually 100% or less, preferably 90% or less, and more preferably 85% or less.

[0077]

[0078] In formula (2), S α－２ (λ) is the spectral absorption spectrum of the dye (α-2), V(λ) is the standard luminous efficiency curve, and λ is the measurement wavelength (nm) and is 380 to 800.

[0079] The present liquid crystal composition preferably contains, as the dichroic dye (A), three or more dyes having an absorption maximum wavelength in a wavelength region of 480 nm or more, namely, dye (α-1), dye (α-2), and dye (α-3), in order of shortest absorption maximum wavelength, and the dye (α-3) satisfies the following mathematical formula (3): The following mathematical formula (3) represents the visual absorbance (%) of the dye (α-3). The lower limit of the mathematical formula (3) is 15%, more preferably 25%, and even more preferably 30%. The upper limit is not particularly limited, but is usually 100% or less, preferably 95% or less, and more preferably 90% or less.

[0080]

[0081] In formula (3), S α－３ (λ) is the spectral absorption spectrum of the dye (α-3), V(λ) is the standard luminous efficiency curve, and λ is the measurement wavelength (nm) and is 380 to 800.

[0082] In the present liquid crystal composition, the dichroic dye (A) preferably contains a compound represented by the following general formula (3).

[0083]

[0084] In general formula (3), X ３１ ~X ３４ R each independently represents a hydrogen atom, a hydroxyl group, an amino group, a phenylamino group which may have a substituent, or an arylthio group which may have a substituent. ３１ ~R ３４ each independently represents a hydrogen atom, an optionally substituted phenoxy group, an optionally substituted alkyl group, or an optionally substituted alkoxycarbonyl group.

[0085] In general formula (3), X ３１ ~X ３４represents a phenylamino group which may have a substituent, examples of the substituent which the phenylamino group may have include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group, a neo-pentyl group, a t-pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a cyclopentyl group, a cyclohexyl group, a 2-ethylhexyl group, a 2-propylhexyl group, a 2-butylhexyl group, a trans-4-propyl Examples of the alkyl group include alkyl groups having a linear, branched, or cyclic structure and having 1 to 20 carbon atoms, such as a trans-4-butylcyclohexyl group, a trans-4-butylcyclohexyl group, and a trans-4-pentylcyclohexyl group; and linear or branched alkoxy groups having 1 to 10 carbon atoms, such as a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, an iso-butoxy group, a sec-butoxy group, a t-butoxy group, an n-pentyloxy group, an iso-pentyloxy group, a sec-pentyloxy group, a neo-pentyloxy group, and a t-pentyloxy group.

[0086] In general formula (3), X ３１ ~X ３４ represents an arylthio group which may have a substituent, examples of the arylthio group which may have a substituent include phenylthio groups substituted with an alkyl group having 1 to 20 carbon atoms, such as a phenylthio group, a 4-methylphenylthio group, a 4-tert-butylphenylthio group, a 4-(trans-4-propylcyclohexyl)phenylthio group, a 4-tert-butylphenylthio group, a 4-(trans-4-butylcyclohexyl)phenylthio group, and a 4-(trans-4-pentylcyclohexyl)phenylthio group; phenylthio groups substituted with a haloalkyl group, such as a 4-trifluoromethylphenylthio group, and halophenylthio groups, such as a 4-chlorophenylthio group; naphthylthio groups, such as a 1-naphthylthio group and a 2-naphthylthio group; and heteroarylthio groups, such as a 2-pyridylthio group.

[0087] In general formula (3), R ３１ ~R ３４represents a phenoxy group which may have a substituent, examples of the substituent which the phenoxy group may have include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group, a neo-pentyl group, a t-pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a cyclopentyl group, a cyclohexyl group, and a 2-ethylhexyl group. linear or branched alkyl groups having 1 to 10 carbon atoms such as 2-propylhexyl group, 2-butylhexyl group, etc.; linear or branched alkoxy groups having 1 to 10 carbon atoms such as methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, iso-butoxy group, sec-butoxy group, t-butoxy group, n-pentyloxy group, iso-pentyloxy group, sec-pentyloxy group, neo-pentyloxy group, and t-pentyloxy group.

[0088] In general formula (3), R ３１ ~R ３４ represents an alkyl group which may have a substituent, examples of the alkyl group include linear or branched alkyl groups having 1 to 10 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, sec-pentyl, neo-pentyl, t-pentyl, hexyl, heptyl, octyl, nonyl, decyl, cyclopentyl, cyclohexyl, 2-ethylhexyl, 2-propylhexyl, 2-butylhexyl, and 3,5,5-trimethylhexyl.

[0089] In general formula (3), R ３１ ~R ３４When represents an alkoxycarbonyl group which may have a substituent, examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, an n-propyloxycarbonyl group, an isopropyloxycarbonyl group, an n-butyloxycarbonyl group, an isobutyloxycarbonyl group, a sec-butyloxycarbonyl group, a t-butyloxycarbonyl group, an n-pentyloxycarbonyl group, an isopentyloxycarbonyl group, and a sec-pentyloxycarbonyl group. Examples of the alkyloxycarbonyl group include alkyloxycarbonyl groups having a linear, branched, or cyclic structure having 2 to 20 carbon atoms, such as a phenyl group, a neo-pentyloxycarbonyl group, a t-pentyloxycarbonyl group, a hexyloxycarbonyl group, a trans-4-propylcyclohexyloxycarbonyl group, a trans-4-butylcyclohexyloxycarbonyl group, a trans-4-pentylcyclohexyloxycarbonyl group, and a trans-4-hexylcyclohexyloxycarbonyl group.

[0090] Among the dichroic dyes represented by the general formula (3), from the viewpoint of exhibiting a broad absorption spectrum suitable for color mixing, ３１ is an arylthio group which may have a substituent, and X ３２ and X ３４ is a hydrogen atom, and X ３ is a phenylamino group which may have a substituent, and R ３１ ~R ３４ is a hydrogen atom. Specific examples of the magenta dye represented by compound (a1) include the following:

[0091]

[0092] Among the dichroic dyes represented by the general formula (3), from the viewpoint of having an absorption peak in a wavelength range with high luminosity and exhibiting a high OD value, X ３１ and X ３３ is an arylthio group which may have a substituent, and X ３２ and X ３４ is a hydroxyl group, and R ３１ and R ３３ is a hydrogen atom, and R ３２ and R３４ is a hydrogen atom or an alkyl group which may have a substituent. Specific examples of suitable violet dyes represented by compound (a2) include the following:

[0093]

[0094] In addition, in the dichroic dye represented by the general formula (3), examples of a dye having the same color tone as (a2) but with a different structure include X ３１ is an amino group, and X ３２ is an arylthio group which may have a substituent, and X ３３ and X ３４ is a hydrogen atom, and R ３１ is an alkoxycarbonyl group which may have a substituent, and R ３２ , R ３３ and R ３４ In view of increasing the OD value, the compound (a3) ​​in which is a hydrogen atom is preferred. Specific examples of suitable violet dyes represented by the compound (a3) ​​include the following.

[0095]

[0096] In addition, in the dichroic dye represented by the general formula (3), from the viewpoint of exhibiting a blue color tone and a high OD value, X ３１ ~X ３４ is an amino group, and R ３１ and R ３４ is an optionally substituted phenoxy group, and R ３２ and R ３３ is a hydrogen atom. Specific examples of suitable blue dyes represented by compound (a4) include the following:

[0097]

[0098] In addition, from the viewpoint of adjusting the color tone when mixed to approach black, it is preferable to contain a yellow colorant. In the dichroic dye represented by the general formula (3), examples of the compound exhibiting a yellow color tone include compounds represented by the general formula (3) above, such as X ３１ and X ３３ is an arylthio group which may have a substituent, and X ３２ and X３４ is a hydrogen atom, and R ３１ ~R ３４ is a hydrogen atom.

[0099] Specific examples of suitable yellow dyes represented by compound (a5) include the following.

[0100]

[0101] From the viewpoint of increasing light absorption in the colored state, the present liquid crystal composition preferably contains at least one dye selected from the compounds (a1) to (a4) described above among the dichroic dyes (A), more preferably contains at least two dyes selected from the compounds (a1) to (a4), and even more preferably contains at least three dyes selected from the compounds (a1) to (a4). Among these, combinations containing a magenta dye, a violet dye, and a blue dye are particularly preferred. Furthermore, it is preferred that at least one dye selected from the dichroic dyes is compound (a2). Furthermore, from the viewpoint of adjusting the color tone while increasing the OD value, it is preferred that the liquid crystal composition contains any three dyes selected from the compounds (a1) to (a4) described above and the compound (a5) described above.

[0102] The content of the dichroic dye (A) in the liquid crystal composition is preferably 0.15% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more, based on 100% by mass of the nonvolatile content of the liquid crystal composition. The upper limit is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. When the content is equal to or greater than the lower limit, the light-adjusting element tends to exhibit greater light absorption in the colored state, and the amount of transmitted light tends to be smaller. When the content is equal to or less than the upper limit, separation or precipitation of the dichroic dye is less likely to occur, and the reliability of the liquid crystal element tends to be improved.

[0103] When the dichroic dye (A) contains three types of dye (α-1), dye (α-2), and dye (α-3) in order of shortest absorption maximum wavelength, the content of dye (α-1) relative to the total amount of dichroic dye (A) is preferably 25% by mass or more, more preferably 31% by mass or more, and even more preferably 33% by mass or more. The upper limit is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 42% by mass or less. The content of dye (α-2) relative to the total amount of dichroic dye (A) is preferably 2% by mass or more, more preferably 4% by mass or more, and even more preferably 6% by mass or more. The upper limit is preferably 25% by mass or less, more preferably 22% by mass or less, and even more preferably 19% by mass or less. The content of dye (α-3) relative to the total amount of dichroic dye (A) is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more. The upper limit is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 31% by mass or less. When the contents of the dyes (α-1), (α-2), and (α-3) are equal to or greater than the lower limit, the light-adjusting element tends to exhibit greater light absorption in the colored state and the amount of transmitted light tends to be smaller. When the contents are equal to or less than the upper limit, separation or precipitation of the dichroic dyes is less likely to occur, and the reliability of the liquid crystal element tends to be improved.

[0104] Furthermore, when the present liquid crystal composition contains at least three dyes as the dichroic dye (A), the sum of the contents of the compounds (A1) and (A2) relative to the total weight of the dichroic dye (A) is preferably less than 70% by mass, more preferably 60% by mass or less, even more preferably 50% by mass or less, and preferably 40% by mass or less. The lower limit is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more. By keeping the content below the upper limit, separation or precipitation of the dichroic dye is less likely to occur, and the reliability of the liquid crystal device tends to be improved. By keeping the content above the lower limit, the light-adjusting element tends to exhibit greater light absorption in the colored state, and the amount of transmitted light tends to be reduced.

[0105] The concentration of the dichroic dye (A) dissolved in the liquid crystal compound (B) in the present liquid crystal composition is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, and particularly preferably 1.5% by mass or more. In consideration of application to a light-controlling element that exhibits a high contrast ratio, the higher the solubility, the better.

[0106] [Liquid Crystal Compound (B)] The liquid crystal compound (B) contained in the present liquid crystal composition can be any of various low molecular weight compounds or mixtures such as biphenyl-based, phenylcyclohexane-based, and cyclohexylcyclohexane-based compounds described in "Liquid Crystal Device Handbook," edited by the 142nd Committee of the Japan Society for the Promotion of Science, published by the Japan Industrial Newspaper Co., Ltd. (1989), pages 152 to 192, and "Liquid Crystal Handbook," edited by the Liquid Crystal Handbook Editorial Committee, published by Maruzen Co., Ltd. (2000), pages 260 to 330. It is also possible to use polymer-based compounds or mixtures such as those described in "Liquid Crystal Handbook," edited by the Liquid Crystal Handbook Editorial Committee, published by Maruzen Co., Ltd. (2000), pages 365 to 415. Specific examples are described below.

[0107]

[0108] [Photocurable Compound (C)] The present liquid crystal composition contains a photocurable compound (C). The photocurable compound (C) contains a compound that photocures when irradiated with light. The photocurable compound (C) may be any compound having a functional group that can be polymerized by the action of a photopolymerization initiator (D) described below.

[0109] In the present liquid crystal composition, the photocurable compound (C) preferably includes a mono(meth)acrylate compound and a polyfunctional (meth)acrylate compound. The mono(meth)acrylate compound and the polyfunctional (meth)acrylate compound improve compatibility with the liquid crystal compound (B) in the liquid crystal composition and, when the photocurable compound (C) is photocured by irradiation with light as a light-controlling element described below, the liquid crystal dispersed in the photocurable compound undergoes phase separation, forming a photocured product phase of the photocurable compound and a liquid crystal phase. The photocurable compound (C) preferably includes a mono(meth)acrylate compound and a di(meth)acrylate compound as the polyfunctional (meth)acrylate, which facilitates phase separation between the photocured phase and the liquid crystal phase. These mono(meth)acrylate compounds and polyfunctional (meth)acrylate compounds may be used singly or in combination, as needed.

[0110] Examples of the mono(meth)acrylate compound include ethyl(meth)acrylate, methyl(meth)acrylate, propyl(meth)acrylate, butyl(meth)acrylate, pentyl(meth)acrylate, hexyl(meth)acrylate, heptyl(meth)acrylate, octyl(meth)acrylate, nonyl(meth)acrylate, decyl(meth)acrylate, undecyl(meth)acrylate, dodecyl(meth)acrylate, tridecyl(meth)acrylate, phenoxyethyl(meth)acrylate, 2-hydroxy ... Suitable examples of the acrylate that can be used include acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 6-hydroxyhexyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, ethoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and isobornyl (meth)acrylate.

[0111] The polyfunctional (meth)acrylate compound is a compound having two or more (meth)acryloyl groups in the molecule. The polyfunctional (meth)acrylate compound preferably has 2 to 6 (meth)acryloyl groups, more preferably has 2 to 3 (meth)acryloyl groups, and even more preferably is a di(meth)acrylate having two (meth)acryloyl groups. The polyfunctional (meth)acrylate compound may be either a monomer or an oligomer of the compound described below, or a combination of both.

[0112] Suitable examples of the bifunctional (meth)acrylate monomer include 1,4-butanediol di(meth)acrylate, 1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,7-heptanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,11-undecanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, 1,13-tridecanediol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, and trimethylolpropane di(meth)acrylate.

[0113] Examples of trifunctional (meth)acrylate monomers include trimethylolpropane triacrylate, pentaerythritol triacrylate, tetramethylolpropane triacrylate, caprolactone-modified trimethylolpropane triacrylate, and tri(2-hydroxyethyl isocyanurate)triacrylate.

[0114] Examples of tetrafunctional or higher (meth)acrylate monomers include ditrimethylolpropane tetraacrylate, dipentaerythritol hexaacrylate, and dipentaerythritol pentaacrylate.

[0115] Examples of polyfunctional (meth)acrylate oligomers include urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, copolymers of (meth)acrylate monomers, etc. Among these, urethane (meth)acrylate is preferred from the viewpoint of imparting appropriate toughness to the cured product.

[0116] Urethane (meth)acrylates have urethane bonds formed by bonding structural units derived from polyisocyanate compounds with structural units derived from polyol compounds. Polyisocyanate compounds are classified into aliphatic isocyanates having an aliphatic carbon skeleton and aromatic isocyanates having a skeleton with an aromatic ring. Among these, aliphatic urethane (meth)acrylates using aliphatic isocyanates as the polyisocyanate compound are preferred because of their excellent light resistance. Furthermore, examples of polyol compounds include polyether polyols, polyester polyols, and polycarbonate polyols, and among these, polyether polyols are preferred because they tend to have good adhesion to substrates.

[0117] The mass average molecular weight of the (meth)acrylate oligomer is preferably 1,000 or more and 50,000 or less. If the mass average molecular weight of the (meth)acrylate oligomer is 1,000 or more, the adhesion to the substrate tends to be excellent, and if it is 50,000 or less, the compatibility and curability tend to be excellent.

[0118] Furthermore, the photocurable compound (C) preferably contains a hydroxyl group-containing (meth)acrylate compound. By containing a hydroxyl group-containing (meth)acrylate compound, it is expected that the adhesiveness will be improved and the adhesion to the substrate will be enhanced. Examples of the hydroxyl group-containing (meth)acrylate compound include compounds containing a hydroxyl group among the mono(meth)acrylate compounds and polyfunctional (meth)acrylate compounds exemplified above.

[0119] When the photocurable compound (C) contains a mono(meth)acrylate compound and a polyfunctional (meth)acrylate compound, the mass ratio of the two is preferably 1:9 to 9:1, more preferably 5:5 to 9:1.

[0120] The mass ratio (C:B) of the photocurable compound (C) to the liquid crystal compound (B) is preferably 1:9 to 9:1, and more preferably 1:8 to 8:2.

[0121] [Photopolymerization Initiator (D)] The present liquid crystal composition contains a photopolymerization initiator (D). As the photopolymerization initiator (D), for example, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, benzophenone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, oligo[2-hydroxy-2-methyl-1-[4-(methylvinyl)phenyl]propanone], and the like can be suitably used.

[0122] The photopolymerization initiator preferably has an absorption maximum wavelength of 420 nm or less, more preferably 400 nm or less, and even more preferably 390 nm or less. By using a photopolymerization initiator having an absorption maximum in this wavelength range, it is possible to avoid overlapping absorption with a dichroic dye having absorption in the visible light range and improve the efficiency of the photopolymerization reaction. Furthermore, the present liquid crystal composition may contain two or more of the above photopolymerization initiators in combination. The use of a photopolymerization initiator having an absorption maximum wavelength in the ultraviolet range in combination reduces the influence of light absorption by the dichroic dye and more efficiently suppresses curing inhibition, which is preferable in terms of improving the curability and reliability of the photocurable composition.

[0123] The content of the photopolymerization initiator (D) is preferably 0.01 to 10% by mass, and more preferably 0.1 to 5% by mass, based on 100% by mass of the nonvolatile content of the liquid crystal composition.

[0124] [Other Components] The liquid crystal composition may contain other components in addition to the dichroic dye (A), the liquid crystal compound (B), the photocurable compound (C), and the photopolymerization initiator (D). Examples of such other components include inorganic particles, organic particles, chain transfer agents, photosensitizers, light stabilizers, polymerization inhibitors, antioxidants, viscosity modifiers, leveling agents, antifoaming agents, and plasticizers.

[0125] The liquid crystal composition contains inorganic resin or organic particles as spacer particles, which allows for adjustment of the cell gap when used as a liquid crystal cell. Examples of inorganic particles include amorphous silica, crystalline silica, glass beads, and mixtures thereof. Examples of organic particles include polyolefin, polystyrene, polyurethane, starch, polymethyl methacrylate, and polytetrafluoroethylene. Core-shell structures combining these particles can also be widely used. The content of the spacer particles is preferably 0.01 to 1% by mass, more preferably 0.05 to 0.8% by mass, based on 100% by mass of the nonvolatile components of the liquid crystal composition.

[0126] The present liquid crystal composition is preferred in that it contains a chain transfer agent, which facilitates efficient curing deep within the photocurable compound. Among chain transfer agents, a thiol-based chain transfer agent having two or more thiol groups is preferred. One or more types of thiol-based chain transfer agents can be used in combination. When a thiol-based chain transfer agent is contained, the content thereof is preferably 0.01 to 10% by mass, and more preferably 0.1 to 5% by mass, based on 100% by mass of the nonvolatile content of the liquid crystal composition.

[0127] The liquid crystal composition preferably contains an antifoaming agent, which can suppress the generation of bubbles during the preparation process of the liquid crystal composition and quickly eliminate bubbles that have already been generated. The antifoaming agent is not particularly limited, and may be a silicone-based antifoaming agent or a non-silicone-based antifoaming agent. One or more types of antifoaming agents may be used in combination. Silicone-based antifoaming agents are classified into oil-type, oil compound-type, solution-type, emulsion-type, and self-emulsifying-type based on their product form, and are appropriately selected depending on the type and conditions of the foaming liquid. Examples of non-silicone-based antifoaming agents include organic antifoaming agents such as surfactants, polyethers, and higher alcohols.

[0128] Examples of surfactants include the following: anionic surfactants such as carboxylates, sulfonates, sulfate salts, and phosphate salts; cationic surfactants such as amine salts and quaternary ammonium salts; amphoteric surfactants such as alkylamino fatty acid salts, alkylamine oxides, betaines, sulfobetaines, amidosulfobetaines, carbobetaines, and imidazolines; ether-type surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkylaryl ethers, polyoxyethylene aralkyl ethers, polyoxyethylene aralkylaryl ethers, polyoxyethylene polyoxypropylene block adducts, alkyl glucosides, and polyether-modified silicones; ester-type surfactants such as glycerin fatty acid esters, sorbitan fatty acid esters, and sucrose fatty acid esters; ester-ether-type surfactants such as polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and polyoxyethylene sucrose fatty acid esters; acetyl-type surfactants such as acetyl-modified polyvinyl alcohol; and nonionic surfactants such as fatty acid alkanolamides; and acetylene alcohols.

[0129] Among these, acetylene alcohol is preferred because it tends not to affect the electro-optical properties of the liquid crystal element or the reliability of its heat resistance, light resistance, etc. The acetylene alcohol may have an asymmetric or symmetric structure, and may be a compound having only one hydroxyl group or two or more hydroxyl groups. Among these, a compound having multiple hydrophilic groups and multiple hydrophobic groups is preferred, a compound having a gemini structure having multiple hydrophilic groups and multiple hydrophobic groups in one molecule via a carbon-carbon triple bond is more preferred, and it is even more preferred that the gemini structure is a symmetric structure. Examples of acetylene alcohols include 1-pentyn-3-ol, 2-butyn-1,4-diol, 4,6-nonadecadiyn-1-ol, 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol, 5,8-dimethyl-6-dodecyne-5,8-diol, 2,4,7,9-tetramethyl-5-dodecyne-4,7-diol, 8-hexadecyne-7,10-diol, 7-tetradecyne-6,9-diol, 2,3,6,7-tetramethyl-4-octyne-3,6-diol, 3,6-diethyl-4-octyne-3,6-diol, 2,5-dimethyl-3-hexyne-2,5-diol, and the like, as well as alkylene oxide derivatives of the above-mentioned acetylene alcohols. Commercially available products include, but are not limited to, Surfynol 420, Surfynol 440, Surfynol 465, and Surfynol 485 manufactured by Nissin Chemical Industry Co., Ltd. When an antifoaming agent is contained, the content thereof is preferably 0.01 to 10 mass %, and more preferably 0.1 to 1 mass %, relative to 100 mass % of the nonvolatile content of the liquid crystal composition.

[0130] To improve the workability of applying the liquid crystal composition to a substrate, an organic solvent may be blended into the liquid crystal composition as needed. Examples of organic solvents include aromatic solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone, acetone, methyl isobutyl ketone, and cyclohexanone; ether solvents such as diethyl ether, isopropyl ether, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, anisole, and phenetole; ester solvents such as ethyl acetate, butyl acetate, isopropyl acetate, and ethylene glycol diacetate; amide solvents such as dimethylformamide, diethylformamide, and N-methylpyrrolidone; cellosolve solvents such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve; alcohol solvents such as methanol, ethanol, propanol, isopropanol, and butanol; and halogenated solvents such as dichloromethane and chloroform. These organic solvents may be used alone or in combination. In terms of reducing the environmental load and facilitating control of the particle size of the liquid crystal within a desired range, it is preferable that the composition does not contain an organic solvent. When an organic solvent is contained, the amount of the organic solvent is preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, and particularly preferably 5% by mass or less, relative to the total mass of the liquid crystal composition.

[0131] The liquid crystal composition can be prepared by dissolving the dichroic dye (A) in the liquid crystal compound (B) to form a guest-host liquid crystal composition (GHLC), and then mixing the photopolymerizable resin composition (C) and the photopolymerization initiator (D) into the guest-host liquid crystal composition. The liquid crystal composition thus obtained has high light-shielding properties and excellent curability, and therefore, when applied to a light-controlling element, a light-controlling element with a wide dynamic range and high contrast can be obtained.

[0132] The performance of a guest-host liquid crystal composition containing a dichroic dye (A) and a liquid crystal compound (B) can be evaluated by measuring its transmittance. A guest-host liquid crystal composition containing a dichroic dye (A) at a concentration of 5% by mass is filled into a glass cell with a gap thickness of 10 μm and antiparallel-aligned. The ratio (T⊥ / T / / ) of the visible light transmittance (T / / ) measured by irradiating the cell with light polarized parallel to the alignment direction to the visible light transmittance (T⊥) measured by irradiating the cell with light polarized parallel to the alignment direction is preferably 8.0 or more, more preferably 9.0 or more, and even more preferably 10.0 or more. Within the above range, a liquid crystal composition that is likely to achieve high contrast can be obtained. Visible light transmittance is measured in accordance with JIS R 3106:2019.

[0133] <Photocured Product> The photocured product of the present invention is a photocured product obtained by photocuring the present liquid crystal composition. The photocured product can be obtained by irradiating the liquid crystal composition with light. Examples of the light irradiation source include a high-pressure mercury lamp, a metal halide lamp, a xenon lamp, a halogen lamp, and an LED lamp capable of irradiating ultraviolet light. The curing temperature is preferably a temperature at which the liquid crystal composition can be maintained in a homogeneous state, i.e., a temperature higher than the phase separation temperature, and is preferably maintained within a range of 1 to 5°C higher than the phase separation temperature. By maintaining the temperature within this range, the liquid crystal compound (B) and the photocurable compound (C) are less likely to separate before polymerization, and the domain size of the liquid crystal is less likely to become smaller when the polymer obtained by photocuring and the liquid crystal separate.

[0134] <Light Modulating Element> The light modulating element of the present invention comprises a pair of substrates, each of which is a transparent substrate, facing each other, with at least one of the substrates having a transparent electrode, and a layer of a photocured material sandwiched between them. The substrate may be, for example, a substrate having a thin film of an inorganic transparent material such as glass or quartz, a metal, a metal oxide, a semiconductor, or an organic conductive material formed on the entire surface or in part of the substrate by a known coating method, printing method, or vapor deposition method such as sputtering. Alternatively, the substrate may be partially etched after forming a conductive thin film. In particular, to obtain a large-area light modulating element, it is desirable to use an electrode substrate in which an ITO (indium oxide, tin oxide) electrode is formed on a transparent polymer film such as PET by a vapor deposition method such as sputtering or a printing method, from the standpoints of productivity and processability. Wiring may be provided on the substrate to connect the electrodes or the electrodes to the outside. For example, the substrate may be a segment driving electrode substrate, a matrix driving electrode substrate, an active matrix driving electrode substrate, or the like. Furthermore, the electrode surface of the substrate may be formed of an organic compound such as polyimide, polyamide, silicon, or a cyanide compound, or SiO ２ , TiO ２ , ZrO ２ The entire surface or a part of the surface may be covered with a protective film or an alignment film made of an inorganic compound such as those mentioned above, or a mixture thereof.

[0135] When a plastic film is used as the substrate, a flexible and lightweight light-controlling element can be obtained. Therefore, the light-controlling element can be sandwiched between a pair of flat or curved glass or hard plastic substrates via an adhesive layer such as polyvinyl butyral, vinyl acetate ester, double-sided tape, or adhesive, or attached to the surface of a single flat or curved glass or hard plastic substrate using double-sided tape or adhesive. It can also be sandwiched between soft plastic substrates or attached to one or both sides. A protective layer such as a hard coat, an ultraviolet-blocking layer, an infrared-blocking layer, or a half mirror may be provided on the substrate surface opposite the electrode surface of the light-controlling element, or a color filter or polarizer filter may be laminated thereon. A color plate may also be placed behind the light-controlling element. Furthermore, the light-controlling element can be cut to the desired size and shape before use. It can also be laminated with an electroluminescent display element, a light-emitting diode display element, an electrochromic display element, or another liquid crystal display element.

[0136] The light-adjusting element of the present invention has a total light transmittance (TT) ｏｆｆ ) when the voltage is ON (TT ｏｎ ) ratio (TT ｏｎ / TT ｏｆｆ ) is preferably 1.75 or more, more preferably 1.85 or more, and even more preferably 2.00 or more. The higher the transmittance ratio, the better.

[0137] In addition, the haze when the voltage is ON ｏｎ ) when the voltage is OFF (HAZE ｏｆｆ ) ratio (HAZE ｏｆｆ / HAZE ｏｎ The value of the haze ratio is preferably 20 or more, more preferably 25 or more, and even more preferably 30 or more. The higher the value of the haze ratio, the better.

[0138] In addition, because the photochromic element of the present invention contains a dichroic dye in the photocured product, there is a possibility that colored liquid crystal or the like may seep out from the edge of the photochromic element and contaminate the surrounding area. To prevent this, the edge of the photochromic element can be protected with tapes such as adhesive tape, thermocompression tape, and thermosetting tape, and / or curable resins or thermoplastic resins such as thermosetting resins, photocurable resins, moisture-curable resins, room-temperature curable adhesives, anaerobic adhesives, silicone adhesives, fluorine resin adhesives, polyester adhesives, and vinyl chloride adhesives, thereby preventing the surrounding area from being contaminated. This protection may also serve to prevent deterioration of the photochromic element. In this case, the edge can be protected by covering the entire edge, or by pouring curable resins or thermoplastic resins into the interior of the photochromic element from the edge and solidifying them, and then covering this with tape.

[0139] The light control element of the present invention can be suitably used in in-vehicle components, building components, wearable devices, etc., and can also be applied to light control windows and light control sunroofs equipped with the light control element of the present invention.

[0140] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention.

[0141] Experimental Example 1 Dichroic Dye As the compound (A1), dyes (A1-1) and (A1-2) prepared in Synthesis Examples 1 and 2 were prepared.

[0142] Synthesis Example 1 (Step 1) Synthesis of Intermediate 1-1 Under a nitrogen atmosphere, 1,5-dihydroxyanthraquinone (66.1 g), water (890 ml), and sodium hydroxide (66 g) were mixed, and sodium dithionite (239.6 g) was added, followed by heating to an internal temperature of 45°C. Heptanal (157.1 g) was added dropwise, and the mixture was stirred at an internal temperature of 80°C for 2.5 hours. After cooling to room temperature, the solid was collected by suction filtration, washed successively with water (500 ml), 2N hydrochloric acid (500 ml), water (1,000 ml), and methanol (300 ml), and then dried under reduced pressure to obtain Intermediate 1-1 (27.3 g) represented by the following formula.

[0143]

[0144] (Step 2) Synthesis of Intermediate 1-2 A mixture of intermediate 1-1 (24.9 g) and concentrated hydrochloric acid (125 ml) was cooled to an internal temperature of 5°C or less, and a mixture of fuming nitric acid (specific gravity 1.45, 7.4 ml) and concentrated hydrochloric acid (3.9 ml) was added dropwise over 30 minutes while maintaining the internal temperature at 15°C or less. The mixture was then stirred at room temperature for 1 hour. The reaction solution was poured into ice water (1 L), and the precipitated solid was collected by suction filtration and washed with methanol (500 ml). The obtained solid was dissolved in tetrahydrofuran (100 mL), and then hexane (300 ml) was added. The resulting precipitate was collected by filtration and dried under reduced pressure to obtain intermediate 1-2 (10.58 g) represented by the following formula:

[0145]

[0146] (Step 3) Synthesis of Intermediate 1-3: Under a nitrogen atmosphere, benzenethiol (1.09 g) was added dropwise to a mixture of Intermediate 1-2 (5 g) and pyridine (50 ml), and the mixture was stirred at room temperature for 2.5 hours. Water (100 ml) was added to the reaction mixture, and the precipitated solid was collected by suction filtration and washed with methanol (100 ml). Purification by silica gel column chromatography yielded Intermediate 1-3 (4.44 g) represented by the following formula:

[0147]

[0148] (Step 4) Synthesis of Compound (A1-1) Intermediate 1-3 (1.80 g) was dissolved in 1,4-dioxane (18 ml) under a nitrogen atmosphere, and potassium t-butoxide (0.343 g) was added, followed by stirring at an internal temperature of 60°C for 20 minutes. A solution of 4-tert-butylbenzenethiol (0.507 g) in 1,4-dioxane (1 ml) was added dropwise over 10 minutes, and the mixture was stirred at an internal temperature of 80°C for 5 hours. After cooling to room temperature, water (20 ml) was added, and the precipitated solid was collected by suction filtration and washed with methanol. The solid was purified by silica gel column chromatography and washed successively with hexane and methanol to obtain compound (A1-1) represented by the following formula.

[0149]

[0150] Synthesis Example 2 (Step 1) Synthesis of Intermediate 2-1 Under a nitrogen atmosphere, 1,8-dihydroxyanthraquinone (20.9 g), water (270 ml), and sodium hydroxide (20.9 g) were mixed, and sodium dithionite (79.73 g) was added, followed by heating to an internal temperature of 45°C. Heptanal (49.67 g) was added dropwise, and the mixture was stirred at an internal temperature of 80°C for 8 hours. After cooling to room temperature, the solid was collected by suction filtration, washed successively with water (300 ml), 2N hydrochloric acid (300 ml), water (500 ml), and methanol (300 ml), and then dried under reduced pressure to obtain Intermediate 2-1 (12.74 g) represented by the following formula.

[0151]

[0152] (Step 2) Synthesis of Intermediate 2-2 A mixture of intermediate 2-1 (12.5 g) and concentrated hydrochloric acid (100 ml) was cooled to an internal temperature of 5°C or less, and a mixture of fuming nitric acid (specific gravity 1.45, 5.0 ml) and concentrated hydrochloric acid (7.8 ml) was added dropwise over 30 minutes while maintaining the internal temperature at 15°C or less. The mixture was then stirred at room temperature for 2 hours. The reaction solution was poured into ice water (1 L), and the precipitated solid was collected by suction filtration and washed with methanol (500 ml). The mixture was dried under reduced pressure to obtain intermediate 2-2 (8.81 g) represented by the following formula.

[0153]

[0154] (Step 3) Synthesis of Intermediate 2-3: Under a nitrogen atmosphere, benzenethiol (0.817 g) was added dropwise to a mixture of Intermediate 2-2 (4 g) and pyridine (40 ml), and the mixture was stirred at room temperature for 2 hours. 2N hydrochloric acid (300 ml) was added to the reaction mixture, and the precipitated solid was collected by suction filtration and dried under reduced pressure to obtain Intermediate 2-3 (3.20 g) represented by the following formula:

[0155]

[0156] (Step 4) Synthesis of Dye (A1-2) Intermediate 2-3 (2.0 g) was dissolved in 1,4-dioxane (20 ml) under a nitrogen atmosphere, and potassium t-butoxide (0.381 g) was added, followed by stirring at an internal temperature of 60°C for 20 minutes. A solution of 4-tert-butylbenzenethiol (0.564 g) in 1,4-dioxane (1 ml) was added dropwise over 10 minutes, and the mixture was stirred at an internal temperature of 80°C for 5 hours. After cooling to room temperature, 0.7 N hydrochloric acid (60 ml) was added, and the precipitated solid was collected by suction filtration and washed with methanol (10 ml). The product was purified by silica gel column chromatography and washed successively with hexane and methanol to obtain dye (A1-2) represented by the following formula:

[0157]

[0158] [Liquid Crystal Compound] A nematic liquid crystal mixture (E8) containing 43 mol% of 5CB, 17 mol% of 3OCB, 13 mol% of 5OCB, 17 mol% of 8OCB, and 10 mol% of 5CT, represented by the following formula, was prepared. The NI point (nematic phase-isotropic phase transition temperature) of the liquid crystal mixture (E8) was 72°C.

[0159]

[0160] [Photopolymerizable Resin Composition] Loctite 3736 (manufactured by Henkel) was prepared as a photopolymerizable resin composition. The composition contains aliphatic urethane acrylate, isobornyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and hydroxyethyl methacrylate as photocurable compounds (C), and 2,2-dimethoxy-1,2-diphenylethan-1-one, 2-hydroxy-2-methyl-1-phenylpropanone, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide as photopolymerization initiators (D). Of the photocurable compounds, the aliphatic urethane acrylate is the oligomer component, and the isobornyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and hydroxyethyl methacrylate are the monomer components.

[0161] Example 1-1 A guest-host liquid crystal composition (GHLC) was prepared by dissolving 1% by mass of a dichroic dye (dye A1-1) in liquid crystal mixture (E8). The prepared liquid crystal composition was mixed with a commercially available photopolymerizable resin composition (Loctite 3736, manufactured by Henkel) in a mass ratio of 1:1 to prepare a mixed solution. 0.1% by mass of 10 μm diameter silica particle spacers (Hipressica, manufactured by Ube Exsymo Co., Ltd.) were added to the prepared mixed solution and stirred to prepare liquid crystal composition 1-1.

[0162] Liquid crystal composition 1 was coated to a thickness of 10 μm on the ITO-treated surface of a polyethylene terephthalate (PET) film, one side of which was coated with ITO, using a bar coater. Another ITO-coated PET film was laminated with a hand roller so that the ITO surface was in contact with the coated surface. The laminated film was irradiated with UV light at an irradiation intensity of 9.1 mW / cm2 for 10 seconds using an LED with a peak wavelength of 365 nm as a light source, photocuring liquid crystal composition 1 and producing light control element 1-1.

[0163] Example 1-2 A liquid crystal composition and a light-adjusting element 1-2 were prepared in the same manner as in Example 1-1, except that the dye (A1-2) was used as the dichroic dye.

[0164] [Comparative Examples 1-1 and 1-2] Liquid crystal compositions 1-3 and 1-4 and light-adjusting elements 1-3 and 1-4 were prepared in the same manner as in Example 1-1, except that dyes (A1'-3) and (A1'-4) represented by the following formulas were used as dichroic dyes.

[0165]

[0166]

[0167] [Evaluation] (OD Value) The dye used in Experimental Example 1 was dissolved in chloroform to prepare a 1 mg / 100 mL dye solution. Each prepared dye solution was placed in a measurement cell with an optical path length of 1 cm, and the light absorption spectrum at wavelengths of 280 to 800 nm was measured using a spectrophotometer (U-4100, manufactured by Hitachi High-Technologies Corporation). The maximum absorbance value (Absmax) was read from the obtained absorbance curve. The ratio (Absmax / c) of the maximum absorbance value to the concentration (c (mg / mL)) of the dye solution was calculated and used as the OD value of the dichroic dye. The wavelength showing the maximum absorbance value (maximum absorption wavelength) and the OD value are shown in Table 1.

[0168] (Solubility Evaluation 1) The solubility of the dye used in Experimental Example 1 in the liquid crystal was measured as follows. 5% by mass of the dye was added to the liquid crystal mixture (E8) cooled to −10° C. while shaking it in a shaker, and the mixture was shaken at −10° C. for 100 hours. The mixture was then filtered through a 0.2 μm syringe filter to remove insoluble components. The obtained liquid crystal solution was diluted with chloroform, and the absorption spectrum was measured with a Hitachi U-4100 spectrophotometer using a quartz cell with a measurement path length of 10 mm. The absorbance at the absorption maximum wavelength λmax (nm) and the previously measured molar extinction coefficient ε (Lmol －１ ・cm －１ The dissolution concentration (solubility 1) (mass %) of the dye was calculated from the relationship with the dye content (solubility 1). The dissolution concentration (solubility 1) when all of the dye added to the liquid crystal mixture was dissolved was expressed as "≧5%" in the table.

[0169] (Dichroism Evaluation) A guest-host liquid crystal composition (GHLC) was prepared by dissolving 0.1% by mass of each of the dyes used in Experimental Example 1 in the liquid crystal mixture (E8). This was filled into a 50 μm-gap glass cell that had been antiparallel aligned to prepare a GH liquid crystal cell. The absorption spectrum of the prepared cell was measured using a spectrophotometer (U-4100, manufactured by Hitachi High-Technologies Corporation). An absorption spectrum (A / / ) was obtained by irradiating the liquid crystal with light parallel to the alignment direction, and an absorption spectrum (A⊥) was obtained by irradiating the liquid crystal with light perpendicular to the alignment direction. The maximum absorption wavelength (λmax) of each dye was read from the obtained spectrum, and the order parameter (S value) at the maximum absorption wavelength (λmax) was calculated using the following formula (1): S value = (A / / - A⊥) / (A / / + 2A⊥) (1) In the formula, "A / / " and "A⊥" respectively represent the absorbance of the dye for light polarized parallel to the alignment direction of the liquid crystal and the absorbance of the dye for light polarized perpendicular to the alignment direction of the liquid crystal. Theoretically, the S value ranges from 0 to 1, and the closer the value is to 1, the more improved the contrast (dichroism) of the guest-host liquid crystal element. Regarding dichroism, an S value of 0.75 or more was rated as A, and an S value of less than 0.75 was rated as B.

[0170] (Evaluation of Polymerization Inhibition) The photochromic element 1-1 obtained in Example 1-1 was photographed at a magnification of 200x using an optical microscope (Nikon Corporation, ECLIPSE ME600) and analyzed. The analysis range was set to an arbitrary 245 μm × 395 μm range of the sample. The obtained image ( FIG. 1 ) was binarized using Nikon software (NIS-Elements D) by adjusting the image brightness and contrast so that the liquid crystal portion was black and the other portions were white ( FIG. 2 ). The area ratio of the black region in the binarized image was determined to be 95%.

[0171] For the light control element 1-2 obtained in Example 1-2, the light control element 1-3 obtained in Comparative Example 1-1, and the light control element 1-4 obtained in Comparative Example 1-2, images (Figures 3, 5, and 7) taken under the same conditions as in Example 1-1 were binarized and analyzed. The area percentages of black regions in the binarized images (Figures 4, 6, and 8) were 91%, 17%, and 78%, respectively. It was confirmed that the liquid crystal compositions of Examples 1-1 and 1-2 underwent photopolymerization organic phase separation upon UV irradiation, resulting in the formation of microdroplets containing liquid crystal (liquid crystal droplets) over the entire surface of the light-irradiated surface. The liquid crystal composition of Comparative Example 1-3 underwent polymerization inhibition upon UV irradiation, resulting in insufficient liquid crystal droplet formation and many areas where no liquid crystal was present. Furthermore, the size of the partially formed droplets was large, resulting in significantly inferior quality as an element. The liquid crystal composition of Comparative Example 1-4 exhibited inferior curability upon UV irradiation compared to the liquid crystal compositions of the Examples, resulting in more areas where no liquid crystal was present than in the light control elements of the Examples. In addition, the S value was low and the contrast was poor.

[0172] Regarding the curability of the liquid crystal composition, if the area of ​​the black portion obtained by the above analysis was less than 50%, it was judged as C, if it was 50% or more but less than 80%, it was judged as B, and if it was 80% or more, it was judged as A.

[0173]

[0174] Experimental Example 2 [Dichroic Dye] As the compound (A2), the following dye (A2-1) was synthesized by the following procedure.

[0175]

[0176] In a reaction vessel, a mixture of N-methyl-2-pyrrolidone (385 ml), p-cresol (90.7 g), and potassium carbonate (21.7 g) was heated to an internal temperature of 133°C, and intermediate-1 (77 g) represented by the following formula was added thereto over a period of about 15 minutes.

[0177]

[0178] After stirring for 1.5 hours at an internal temperature of 132°C, the mixture was cooled to room temperature, and methanol (1,150 ml) and water (385 ml) were added. The precipitate was collected by suction filtration and washed with methanol (450 ml) and water (450 ml). The resulting solid was dried under reduced pressure to obtain Intermediate-2 (71.2 g) represented by the following formula.

[0179]

[0180] To the intermediate-2 (78.6 g) obtained above, concentrated sulfuric acid (786 ml) cooled to 0°C was added over 20 minutes while maintaining the internal temperature at 9°C or below. After stirring for 2 hours at an internal temperature of 5 to 8°C, the reaction solution was poured into 1,600 g of ice water, and the precipitate was collected by suction filtration. The collected precipitate was washed by sprinkling water (800 ml), a 5% aqueous sodium hydroxide solution (600 ml), and water (600 ml) in this order, and the resulting solid was dried under reduced pressure. Purification was performed by silica gel column chromatography to obtain 26.3 g of dye (A2-1) represented by the above formula.

[0181] Example 2-1 A guest-host liquid crystal composition (GHLC) was prepared by dissolving 1% by mass of a dichroic dye (A2-1) in a liquid crystal mixture (E8) prepared in the same manner as in Experimental Example 1. The prepared liquid crystal composition was mixed with a commercially available photopolymerizable resin composition (Loctite 3736, manufactured by Henkel) in a mass ratio of 1:1 to prepare a mixed solution. 0.1% by mass of 10 μm diameter silica particle spacers (Hipressica, manufactured by Ube Exsymo Co., Ltd.) were added to the prepared mixed solution and stirred to prepare liquid crystal composition 2-1.

[0182] Liquid crystal composition 2-1 was coated to a thickness of 10 μm on the ITO-treated surface of a polyethylene terephthalate (PET) film, one side of which was coated with ITO, using a bar coater. Another ITO-coated PET film was laminated with a hand roller so that the ITO surface was in contact with the coated surface. The laminated film was irradiated with an LED having a peak wavelength of 365 nm to photocure liquid crystal composition 2-1. Irradiation intensity: 9.1 mW / cm ２ By irradiating the resin with UV light for 60 seconds, the reaction proceeded without causing any inhibition of curing, and a light-adjusting element 2-1 of Example 2-1 was obtained.

[0183] [Comparative Examples 2-1 and 2-2] Liquid crystal compositions 2-2 and 2-3 and dimming elements 2-2 and 2-3 were prepared in the same manner as in Example 2-1, except that dyes (A2'-2) and (A2'-3) represented by the following formulas were used as dichroic dyes.

[0184]

[0185]

[0186] [Evaluation] (OD Value) The dye used in Experimental Example 2 was dissolved in chloroform to prepare a 1 mg / 100 mL dye solution. Each prepared dye solution was placed in a measurement cell with an optical path length of 1 cm, and the light absorption spectrum at wavelengths of 280 to 800 nm was measured using a spectrophotometer (U-4100, manufactured by Hitachi High-Technologies Corporation). The maximum absorption wavelength was read from the obtained absorbance curve. The ratio (Absmax / c) of the absorbance (Absmax) at the maximum absorption wavelength to the concentration (c (mg / mL)) of the dye solution was calculated and used as the OD value of the dichroic dye.

[0187] (Solubility Evaluation 2) The solubility of the dye used in Experimental Example 2 in the liquid crystal was measured as follows. 1% by mass of the dye was added to the liquid crystal mixture (E8) cooled to -10°C while shaking it in a shaker, and the mixture was shaken at a temperature of -10°C for 100 hours. The mixture was then filtered through a 0.2 μm syringe filter to remove insoluble components. The obtained liquid crystal solution was diluted with chloroform, and the absorption spectrum was measured with a Hitachi U-4100 spectrophotometer using a quartz cell with a measurement path length of 10 mm. The absorbance at the absorption maximum wavelength λmax (nm) and the previously measured molar extinction coefficient ε (Lmol －１ ・cm －１ ) and the dissolution concentrations (solubility 2) (mass %) of dyes 1 to 4 were calculated from the relationship between the dissolution concentration (solubility 2) and the dissolution rate (solubility 2) of dyes 1 to 4. The dissolution concentration when all of the dyes added to the liquid crystal mixture were dissolved is indicated as "≧1%" in the table. The dissolution concentrations (solubility 2) of less than 0.1% are indicated as "<0.1%" in the table.

[0188] (Dichroism Evaluation) A guest-host liquid crystal composition (GHLC) was prepared by dissolving 0.1% by mass of each of the dyes used in Experimental Example 2 in the liquid crystal mixture (E8). This was filled into a 50 μm-gap glass cell that had been antiparallel aligned to prepare a GH liquid crystal cell. The absorption spectrum of the prepared cell was measured using a spectrophotometer (U-4100, manufactured by Hitachi High-Technologies Corporation). An absorption spectrum (A / / ) was obtained by irradiating the liquid crystal with light parallel to the alignment direction, and an absorption spectrum (A⊥) was obtained by irradiating the liquid crystal with light perpendicular to the alignment direction. The maximum absorption wavelength (λmax) of each dye was read from the obtained spectrum, and the order parameter (S value) at the maximum absorption wavelength (λmax) was calculated using the following formula (4): S value = (A / / - A⊥) / (A / / + 2A⊥) (4) In the formula, "A / / " and "A⊥" respectively represent the absorbance of the dye for light polarized parallel to the alignment direction of the liquid crystal and the absorbance of the dye for light polarized perpendicular to the alignment direction of the liquid crystal. Theoretically, the S value ranges from 0 to 1, and the closer the value is to 1, the more improved the contrast (dichroism) of the guest-host liquid crystal element. Regarding dichroism, an S value of 0.75 or more was rated as A, and an S value of less than 0.75 was rated as B.

[0189] [Evaluation of light-controlling elements] For the light-controlling elements 2-1 to 2-3 prepared in Experimental Example 2, the total light transmittance was measured when an applied voltage (rectangular wave of 60 Hz and 100 Vrms) was turned on and off. A haze meter NDH5000SP (manufactured by Nippon Denshoku Industries Co., Ltd.) was used to measure the total light transmittance. The total light transmittance (TT) when the voltage was turned off was ｏｆｆ ), total light transmittance when voltage is ON (TT ｏｎ ), and the ratio of the total light transmittance when the voltage is ON to the total light transmittance when the voltage is OFF (TT ｏｎ / TT ｏｆｆ The haze (HAZE) value when the voltage was turned off was also calculated. ｏｆｆ ), haze when voltage is ON (HAZE ｏｎ ), and the ratio of the haze when the voltage is OFF to the haze when the voltage is ON (HAZE ｏｆｆ / HAZE ｏｎ ) was calculated.

[0190]

[0191] Example 2-1, which contained the compound (A2) as a dichroic dye, exhibited excellent dichroism and also exhibited a remarkable effect in performance as a light-control element. Specifically, the ratio of the total light transmittance when the voltage was ON to the total light transmittance when the voltage was OFF (TT ｏｎ / TT ｏｆｆ ) is high, and the ratio of haze when the voltage is OFF to haze when the voltage is ON (HAZE ｏｆｆ / HAZE ｏｎ ) also showed high values. These results indicate that the liquid crystal composition has high contrast performance, greatly improving its practical use as a light-adjusting element. On the other hand, in Comparative Example 2-1, a dichroic dye having a molecular weight exceeding the specified range of the present invention was used, resulting in a decrease in contrast performance and a tendency for poor visibility as a light-adjusting element. Furthermore, in Comparative Example 2-2, a dichroic dye having a different substituent position was used, resulting in a significant deterioration in solubility in the liquid crystal, insufficient coloring, and inability to be used in practical use from the viewpoint of hiding power.

[0192] Experimental Example 3 Dichroic Dye The following Dyes 1 to 7 were prepared as dichroic dyes (A). Table 1 shows the maximum absorption wavelength (Λmax), OD value, and visual absorbance of Dyes 1 to 7.

[0193] Dye 1: a compound represented by the following formula:

[0194]

[0195] Dye 2: a compound represented by the formula (a1-1) Dye 3: a compound represented by the formula (a3-1) Dye 4: a compound represented by the formula (a2-1) Dye 5: a compound represented by the formula (a4-2) Dye 6: a compound represented by the formula (a4-3)

[0196] Dye 7: a compound represented by the following formula:

[0197]

[0198] [Evaluation of Dichroic Dye] The dichroic dye used in Experimental Example 3 was evaluated as follows.

[0199] (OD value) The dye was dissolved in chloroform to prepare a 1 mg / 100 mL dye solution. The prepared dye solution was placed in a measurement cell with an optical path length of 1 cm, and the light absorption spectrum at wavelengths of 380 to 800 nm was measured using a spectrophotometer (Hitachi High-Technologies Corporation, U-4100). From the obtained absorbance curve, the maximum absorption wavelength (Λmax) and the maximum absorbance value at the maximum absorption wavelength (Absmax) were read. The ratio (Absmax / c) of the maximum absorbance value to the concentration (c (mg / mL)) of the dye solution was calculated and used as the OD value of the dichroic dye.

[0200] (Visual absorbance) The absorbance curve (S(λ)) representing the absorbance of the dye at wavelength λ obtained by OD value evaluation is multiplied by the value of the standard relative luminous efficiency curve (V(λ)), and the product is integrated over the range of 380 to 800 nm. This value is divided by the integrated value of the value of the standard relative luminous efficiency curve to obtain the visual absorbance, which is expressed by the following mathematical formula (I). The visual absorbance (%) of each dye calculated based on the following mathematical formula (I) is shown in Table 3. (In formula (I), S(λ) is the spectral absorption spectrum of the dye, and V(λ) is the standard luminous efficiency curve. λ is the measurement wavelength (nm) and is 380 to 800.)

[0201]

[0202] [Preparation of Guest-Host Liquid Crystal Compositions] Dichroic dyes of compositions 1 to 5 shown in Tables 4 to 8 were dissolved in a liquid crystal mixture (E8) prepared in the same manner as in Experimental Example 1 to prepare guest-host liquid crystal compositions (GHLC) 3-1 to 3-5 containing 5% by mass of the dichroic dye.

[0203]

[0204]

[0205]

[0206]

[0207]

[0208] The guest-host liquid crystal compositions 3-1 to 3-5 were filled into antiparallel-aligned glass cells (cell gap 10 μm), and the visible light transmittance (T / / ) measured by irradiating with light polarized parallel to the alignment direction and the visible light transmittance (T⊥) measured by irradiating with light polarized perpendicular to the alignment direction were measured. The transmittance ratio (T⊥ / T / / ) was calculated from T / / and T⊥. The results are shown in Table 9. The results in Table 9 indicate that compositions containing a large amount of a dye with high luminous absorbance have a higher transmittance ratio (T⊥ / T / / ) than compositions containing a small amount. Visible light transmittance was measured in accordance with JIS R 3106:2019.

[0209]

[0210] [Photopolymerizable Resin Composition] Loctite 3736 (manufactured by Henkel) was prepared as a photopolymerizable resin composition. The photopolymerizable resin composition contained polyether urethane acrylate, isobornyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and hydroxyethyl methacrylate as the photocurable compound (C), and 2,2-dimethoxy-1,2-diphenylethan-1-one, 2-hydroxy-2-methyl-1-phenylpropanone, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide as the photopolymerization initiator (D). Of the photocurable compounds, urethane acrylate was the oligomer component, and isobornyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and hydroxyethyl methacrylate were the monomer components.

[0211] [Preparation of Liquid Crystal Compositions] The prepared guest-host liquid crystal compositions 3-1 to 3-5 were mixed with a commercially available photopolymerizable resin composition (Loctite 3736, manufactured by Henkel) in a weight ratio of 1:1 to prepare mixed solutions. 20 μm diameter silica particle spacers (Hipressica, manufactured by Ube Exsymo Co., Ltd.) were added to each of the prepared mixed solutions at a ratio of 0.1 wt % and stirred to prepare liquid crystal compositions 3-1 to 3-4 of Examples 3-1 to 3-4 and liquid crystal composition 3-5 of Comparative Example 3-1.

[0212] [Preparation of light-adjusting element] Liquid crystal composition 1 was coated to a thickness of 20 μm on the ITO-treated surface of a polyethylene terephthalate (PET) film, one side of which was coated with ITO, using a bar coater. Another ITO-coated PET film was laminated with a hand roller so that the ITO surface was in contact with the coated surface. Liquid crystal composition 3-1 was cured on the above laminated film using an LED lamp with a peak wavelength of 365 nm. Irradiation intensity: 38.2 mW / cm ２ By irradiating the liquid crystal composition with UV light for 60 seconds, the reaction proceeded without inhibiting curing, and light control element 3-1 of Example 3-1 was obtained. Light control elements 3-2 to 3-5 were also prepared in the same manner as in Example 3-1, except that liquid crystal compositions 3-2 to 3-5 were used.

[0213] [Evaluation of light-controlling elements] For the light-controlling elements 3-1 to 3-5 of the examples and comparative examples, the total light transmittance was measured when an applied voltage (rectangular wave of 60 Hz and 100 Vrms) was turned on and off. A haze meter NDH5000SP (manufactured by Nippon Denshoku Industries Co., Ltd.) was used to measure the total light transmittance. The total light transmittance (TT) when the voltage was turned off was ｏｆｆ ), total light transmittance when voltage is ON (TT ｏｎ ), and the ratio of the total light transmittance when the voltage is ON to the total light transmittance when the voltage is OFF (TT ｏｎ / TT ｏｆｆ ) are shown in Table 10. From the results in Table 10, it can be seen that the liquid crystal compositions of the present invention have a higher transmittance ratio (T⊥ / T / / ) than compositions with a smaller amount.

[0214]

Claims

1. A liquid crystal composition comprising a dichroic dye (A), a liquid crystal compound (B), a photocurable compound (C), and a photopolymerization initiator (D), wherein the dichroic dye (A) comprises at least one selected from a compound (A1) represented by the following general formula (1) and a compound (A2) represented by the following general formula (2) having a molecular weight of 540 g / mol or less: (In formula (1), X １ ~X ４ are each independently -S-Ar or -OH, and Ar represents an aryl group. Ar may have a linear or branched alkyl group, a haloalkyl group, an alkoxy group, a cycloalkyl group, an aryl group, a heterocyclic group, or a halogen atom as a substituent. However, X １ ~X ４ Of these, two are -S-Ar and two are -OH. １ ~R ４ each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkoxy group, an optionally substituted phenyl group, or an optionally substituted phenoxy group. (In formula (2), R １１ ~R １５ R each independently represents a hydrogen atom, an alkyl group which may have a substituent, or an alkoxy group which may have a substituent. ２１ ~R ２５ each independently represents a hydrogen atom, an alkyl group which may have a substituent, or an alkoxy group which may have a substituent.

2. The liquid crystal composition according to claim 1, wherein the compound (A1) is a compound represented by the following general formula (1-1) or (1-2): (In formulas (1-1) and (1-2), Ar １ ~Ar ４ each independently represents an aryl group which may have an alkyl substituent; R １ ~R ４ each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkoxy group, an optionally substituted phenyl group, or an optionally substituted phenoxy group.

3. In the general formula (2), R １１ ~R １５ , and R ２１ ~R ２５ 3. The liquid crystal composition according to claim 1, wherein each of the groups independently represents a hydrogen atom or an alkyl group having 3 or less carbon atoms.

4. The liquid crystal composition according to claim 1 or 2, wherein the compound (A1) or the compound (A2) has an OD value of 30 or more.

5. The liquid crystal composition according to claim 1 or 2, wherein the compound (A1) or the compound (A2) has an OD value of 48 or more.

6. The liquid crystal composition according to claim 1 or 2, wherein the dichroic dye (A) contains at least three kinds of dyes.

7. The liquid crystal composition according to claim 6, wherein at least one of the three dyes has an OD value of 25 or more.

8. The liquid crystal composition according to claim 1 or 2, wherein the dichroic dye (A) comprises three or more dyes having maximum absorption wavelengths in the wavelength region of 480 nm or more.

9. The liquid crystal composition according to claim 8, wherein the dyes having an absorption maximum wavelength in the wavelength region of 480 nm or more are arranged in order of shortest absorption maximum wavelength as dye (α-1), dye (α-2), and dye (α-3), and the OD value of dye (α-2) is 25 or more.

10. The liquid crystal composition according to claim 8, wherein the dyes having an absorption maximum wavelength in the wavelength region of 480 nm or more are arranged in order of shortest absorption maximum wavelength as dye (α-1), dye (α-2), and dye (α-3), and the OD values ​​of the dye (α-2) and the dye (α-3) are 25 or more.

11. Among the dyes having an absorption maximum wavelength in the wavelength region of 480 nm or more, when the dyes are designated in order of shortest absorption maximum wavelength as dye (α-1), dye (α-2), and dye (α-3), the absorbance S of each of the dyes (α-1), (α-2), and (α-3) measured under the conditions of a chloroform solvent, a concentration of 1 mg / 100 mL, and an optical path length of 1 cm is α－１ , S α－２ , and S α－３ and a standard relative luminosity curve V satisfy the relationship of the following mathematical formula (1): (In formula (1), S α－１ (λ) is the spectral absorption spectrum of the dye (α-1), S α－２ (λ) is the spectral absorption spectrum of the dye (α-2), S α－３ (λ) is the spectral absorption spectrum of the dye (α-3), and V(λ) is the standard luminous efficiency curve. λ is the measurement wavelength (nm), which is 380 to 800.

12. Among the dyes having an absorption maximum wavelength in the wavelength region of 480 nm or more, dye (α-1), dye (α-2), and dye (α-3) are listed in order of shortest absorption maximum wavelength. The absorbance of dye (α-2) measured in chloroform solvent at a concentration of 1 mg / 100 mL and with an optical path length of 1 cm is S α－２ and a standard relative luminosity curve V satisfy the following mathematical formula (2): (In formula (2), S α－２ (λ) is the spectral absorption spectrum of the dye (α-2), and V(λ) is the standard luminous efficiency curve. λ is the measurement wavelength (nm), which is 380 to 800.

13. Among the dyes having an absorption maximum wavelength in the wavelength region of 480 nm or more, dye (α-1), dye (α-2), and dye (α-3) are listed in order of shortest absorption maximum wavelength. The absorbance of dye (α-3) measured in chloroform solvent at a concentration of 1 mg / 100 mL and with an optical path length of 1 cm is S α－３ and a standard relative luminosity curve V satisfy the following formula (3): (In formula (3), S α－３ (λ) is the spectral absorption spectrum of the dye (α-3), and V(λ) is the standard luminous efficiency curve. λ is the measurement wavelength (nm), which is 380 to 800.

14. The liquid crystal composition according to claim 6, wherein the sum of the contents of the compounds (A1) and (A2) is less than 70% by mass relative to the total weight of the dichroic dye (A).

15. A liquid crystal composition according to claim 1 or 2, wherein a guest-host liquid crystal composition comprising the dichroic dye (A) and the liquid crystal compound (B) is filled into an antiparallel aligned glass cell, and the ratio (T⊥ / T / / ) of the visible light transmittance (T / / ) measured by irradiating the cell with light polarized parallel to the alignment direction to the visible light transmittance (T⊥) measured by irradiating the cell with light polarized perpendicular to the alignment direction is 8.0 or more.

16. The liquid crystal composition according to claim 1 or 2, wherein the photocurable compound (C) includes a mono(meth)acrylate compound and a polyfunctional (meth)acrylate compound.

17. The liquid crystal composition according to claim 1 or 2, wherein the photocurable compound (C) includes a urethane (meth)acrylate compound.

18. Use of the liquid crystal composition according to claim 1 or 2 as a light-adjusting element.

19. A photocured product obtained by photocuring the liquid crystal composition according to claim 1 or 2.

20. A light-adjusting element comprising a pair of substrates arranged opposite each other, at least one of which is a transparent substrate having a transparent electrode, and a layer of the photocured product according to claim 19 sandwiched between the pair of substrates.

21. An in-vehicle component comprising the light control element according to claim 20.

22. A building component comprising the light control element according to claim 20.

23. A wearable device comprising the photochromic element according to claim 20.

24. A light control window comprising the light control element according to claim 20.

25. A sunroof including the light control element of claim 20.

Images