Light-modulating element and liquid-crystal composition containing anthraquinone compound

Abstract

To provide an anthraquinone compound useful as a dichroic dye for use in a light control element and a liquid crystal composition excellent in contrast.SOLUTION: A liquid crystal composition contains two anthraquinone compounds.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a novel liquid crystal composition. [Background technology]

[0002] Various light-controlling films have been proposed to control the transmission of external light for purposes such as privacy protection in windows, doors, and partitions in vehicles such as trains and automobiles, and buildings such as business buildings and hospitals (Patent Documents 1 and 2). One such light-controlling film uses liquid crystals. Liquid crystal light-controlling films typically can block visibility by controlling the transmission and scattering of light depending on whether or not a voltage is applied, but they cannot block light itself, which tends to increase glare due to light scattering. Therefore, attempts have been made to use dyes as materials for light-controlling panels to reduce glare and improve contrast (Patent Documents 3 and 4). When using such light-controlling panels in automotive windows, there is a growing demand for black elements that can block visible light for practical and aesthetic reasons. Such black light-controlling elements are strongly required to have high contrast with and without the application of voltage, to be close to achromatic both with and without the application of voltage, and to exhibit minimal color change during long-term outdoor use, i.e., when exposed to light at high temperatures for extended periods.

[0003] Dichroic dyes are generally used as dyes in liquid crystal light control films. Known light control elements that use liquid crystal compositions containing dichroic dyes include the GH (guest-host) system and the PDLC (polymer-dispersed liquid crystal) system, in which a composition of dye and liquid crystal is dispersed in a polymer. Various dichroic dyes have been proposed for each system (Patent Documents 4, 5, 6, and 7).

[0004] Dichroic dyes commonly used in liquid crystal compositions for light-adjusting devices require not only a dichroic ratio to enhance contrast when used in a device, but also light resistance, UV resistance, heat resistance, and compatibility (solubility) of the dichroic dye with the components of the liquid crystal composition. Despite efforts to improve these properties, none of these have yet met market demands. For example, Patent Documents 4 and 7 disclose dichroic dye compositions suitable for light-adjusting applications. However, both exhibit significant hue changes upon prolonged exposure to light, and are not sufficiently lightfast for outdoor use. Furthermore, the dichroic dye described in Patent Document 7 has poor practicality due to its low dichroic ratio. Therefore, there is a strong demand for a light-adjusting device that achieves both of these properties. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 63-501512 [Patent Document 2] Japanese Patent Application Publication No. 03-47392 [Patent Document 3] Japanese Patent Application Publication No. 2018-205746 [Patent Document 4] Japanese Patent Application Laid-Open No. 2011-190314 [Patent Document 5] Japanese Patent Application Publication No. 62-5941 [Patent Document 6] WO2021 / 261181 [Patent Document 7] Special Publication No. 03-063589 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a liquid crystal composition that can provide a light-controlling device having a high dichroic ratio, an achromatic color, and excellent light resistance. [Means for solving the problem]

[0007] As a result of extensive research into solving the above problems, the present inventors have found that the above problems can be solved by using two types of dichroic dyes, and have thus completed the present invention.

[0008] Aspects or embodiments of the present invention may be summarized as follows. [1]. A liquid crystal composition comprising (A) a dye compound and (B) a liquid crystal material, wherein the (A) dye compound is (i) The following general formula (1) [ka] (In the formula, R1 represents a linear alkyl group having 1 to 12 carbon atoms. R2 and R3 each independently represent a hydrogen atom, a linear alkoxy group having 4 to 10 carbon atoms, or a group represented by the following formula (a): [ka] (In formula (a), R4 represents a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms. When there are multiple R4s, they may be the same or different.) An anthraquinone compound represented by the formula: (ii) the following general formula (2) [ka] (In the formula, R5 represents a hydrogen atom or an alkyl group having 4 to 10 carbon atoms. R6 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.) A liquid crystal composition comprising an anthraquinone compound represented by the formula: [2]. The liquid crystal composition according to [1], wherein the mass ratio of the anthraquinone compound represented by the general formula (1) to the anthraquinone compound represented by the general formula (2) is 2:1 to 1:2. [3]. The liquid crystal composition according to [1] or [2], wherein the concentration of the dye compound (A) contained in the liquid crystal composition relative to the liquid crystal material (B) is 0.5 to 10% by mass. [4]. The liquid crystal composition according to any one of [1] to [3], comprising an anthraquinone compound represented by the general formula (1) and a dichroic dye other than an anthraquinone compound represented by the general formula (2). [5]. A light-adjusting element comprising a pair of opposing substrates, at least one of which is a transparent substrate having a transparent electrode, and the liquid crystal composition according to any one of [1] to [4] sandwiched between the pair of substrates. [6]. The light-adjusting element according to [5] or [6], wherein both of the pair of substrates are transparent substrates having transparent electrodes. [Effects of the Invention]

[0009] By using the liquid crystal composition of the present invention, a light-controlling device having an achromatic color, high contrast and excellent light resistance can be obtained. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below. In the present invention, the term "lower limit value to upper limit value" means that both the lower limit value and the upper limit value are included. In this specification, the "anthraquinone compound" may be simply referred to as the "compound." Also, in this specification, in accordance with common chemical practice, "branched" hydrocarbyl substituents may include "cyclic" hydrocarbyl substituents (i.e., the residue obtained by removing one hydrogen atom from a cyclic hydrocarbyl group).

[0011] The liquid crystal composition of the present invention contains (A) a dye compound and (B) a liquid crystal material. The dye compound (A) contains both at least one anthraquinone compound represented by the following general formula (1) and at least one anthraquinone compound represented by the following general formula (2):

[0012] [ka] In the anthraquinone compound represented by the general formula (1), R1 represents a linear alkyl group having 1 to 12 carbon atoms. R2 and R3 each independently represent a hydrogen atom, a linear alkoxy group having 4 to 10 carbon atoms, or a group represented by the following formula (a):

[0013] [ka] (In formula (a), R4 represents a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms. When there are multiple R4s, they may be the same or different.) represents a substituent represented by

[0014] [ka] (In the anthraquinone compound represented by the general formula (2), R5 represents a hydrogen atom or an alkyl group having 4 to 10 carbon atoms. R6 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)

[0015] Specific examples of the linear alkyl group having 1 to 12 carbon atoms represented by R1 in general formula (1) include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, an n-undecyl group, and an n-dodecyl group. Of these, a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group are preferred, a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group are more preferred, and an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group are particularly preferred.

[0016] In the general formula (1), examples of the linear alkoxy group having 4 to 10 carbon atoms represented by R2 and R3 include an n-butoxy group, an n-pentyloxy group, an n-hexyloxy group, an n-heptyloxy group, an n-octyloxy group, an n-nonyloxy group, and an n-decyloxy group, with an n-heptyloxy group being particularly preferred.

[0017] Among the linear or branched alkyl groups having 1 to 8 carbon atoms represented by R4 in the general formula (1), specific examples of linear groups include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group. Of these, a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, and an n-hexyl group are preferred, and a methyl group, an ethyl group, an n-propyl group, and an n-butyl group are more preferred. Specific examples of the branched chain include an isopropyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an isopentyl group, an isohexyl group, a t-pentyl group, a 2-methylpentyl group, a 2-methylhexyl group, a 2-methylheptyl group, a 3-methylbutyl group, a 3-methylpentyl group, a 3-methylhexyl group, a 3-methylheptyl group, a 2-ethylpropyl group, a 2-ethylbutyl group, and a 2-ethylhexyl group, of which an isopropyl group, an isobutyl group, a sec-butyl group, and a t-butyl group are preferred.

[0018] The compound represented by the above formula (1) can be synthesized by a conventionally known method described in, for example, JP-A-62-5941, JP-A-2017-518413, JP-A-58-196260, etc.

[0019] Specific preferred examples of the compound represented by the general formula (1) include the following, but the present invention is not limited to these.

[0020] [ka] TIFF2025133090000008.tif106170TIFF2025133090000009.tif194170TIFF2025133090000010.tif151170

[0021] Specific examples of the alkyl group having 4 to 10 carbon atoms represented by R5 in the general formula (2) include linear, branched, and cyclic alkyl groups, of which n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl groups are preferred, and n-heptyl, n-octyl, n-nonyl, and n-decyl groups are more preferred.

[0022] Specific examples of the alkyl group having 1 to 4 carbon atoms represented by R6 in the general formula (2) include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an isopropyl group, an isobutyl group, a sec-butyl group, and a t-butyl group, of which an n-propyl group, an n-butyl group, an isopropyl group, an isobutyl group, a sec-butyl group, and a t-butyl group are preferred, and a t-butyl group is particularly preferred.

[0023] Specific preferred examples of the compound represented by the general formula (2) include the following, but the present invention is not limited to these.

[0024] [ka]

[0025] The compound represented by the general formula (2) can be synthesized by a conventionally known method described in, for example, JP-A-62-5941, JP-T-2017-518413, JP-A-58-196260, and the like.

[0026] The mass ratio of the anthraquinone compounds represented by the general formula (1) and the general formula (2) is not particularly limited, but is usually 10:1 to 1:10, preferably 5:1 to 1:5, and particularly preferably 2:1 to 1:2.

[0027] The content of the anthraquinone compounds represented by the general formulas (1) and (2) in the liquid crystal composition is not particularly limited, but is usually 0.5 to 10 parts by mass, preferably 1 to 8 parts by mass, and more preferably 3 to 8 parts by mass, relative to 100 parts by mass of the liquid crystal material. In the present invention, when a dichroic dye (described below) other than the compounds represented by the general formulas (1) and (2) is used in combination, it is preferable that the total content of the dye compound (A) and the dichroic dye other than the dye compound (A) be in the above range.

[0028] The combination of the anthraquinone compounds represented by the general formula (1) and the general formula (2) is not particularly limited, but a combination of an anthraquinone compound represented by the general formula (1) in which R1 is an alkyl group having 4 to 8 carbon atoms (Nos. 1, 2, 4, 5, 19, and 20) and an anthraquinone compound represented by the general formula (2) in which R5 is an alkyl group having 4 to 10 carbon atoms (Nos. 101, 102, and 105) is preferred.

[0029] The liquid crystal material (B) contained in the composition of the present invention is not particularly limited as long as it is a material (a compound having liquid crystal properties) having liquid crystal properties such as nematic liquid crystal, cholesteric liquid crystal, smectic liquid crystal, etc. Examples of the compound having liquid crystal properties include the liquid crystal compounds described in pages 154 to 192 and 715 to 722 of "Liquid Crystal Device Handbook" (edited by the 142nd Committee of the Japan Society for the Promotion of Science, Nikkan Kogyo Shimbun, 1989), specifically Schiff base, azoxy, biphenyl, phenylcyclohexane, ester, terphenyl, biphenylcyclohexane, pyrimidine, dioxane, bicyclooctane, cubane, etc.

[0030] The liquid crystal composition of the present invention may contain an optically active substance that exhibits or does not exhibit a liquid crystal phase, such as a dichroic dye other than the anthraquinone compounds represented by the general formula (1) or the general formula (2), or cholesteryl noenoate, various additives such as an ultraviolet absorber and an antioxidant, a photocurable compound, a photopolymerization initiator, etc.

[0031] In order to adjust the performance of the light-controlling element, such as contrast, light resistance, and hue, a dichroic dye other than the compounds represented by the general formula (1) and the general formula (2) may be used in combination with the composition of the present invention. The dichroic dye that can be used in combination is not particularly limited, and may be selected from, for example, azo dyes, anthraquinone dyes, perylene dyes, quinophthalone dyes, merocyanine dyes, azomethine dyes, phthaloperylene dyes, indigo dyes, azulene dyes, dioxazine dyes, polythiophene dyes, and the like. Specific examples include those described in "Dichroic dyes for Liquid Crystal Display" (AVI Vashchenko, CRC, 1994). Among these, it is preferable to use an azo dye, an anthraquinone dye, a perylene dye, or a quinophthalone dye in combination, it is more preferable to use an azo dye or an anthraquinone dye in combination, and it is even more preferable to use an anthraquinone dye in combination.

[0032] Suitable specific examples of dichroic dyes other than the anthraquinone compounds represented by general formula (1) and the anthraquinone compounds represented by general formula (2) include, but are not limited to, compounds (anthraquinone dyes) represented by the following general formulas (3-1) to (3-3).

[0033] [ka]

[0034] R in formula (3-1) 15 is not particularly limited, but may be a linear or branched alkyl group having 4 to 7 carbon atoms or a substituent represented by the following formula (d):

[0035] [ka]

[0036] (In formula (d), R 21 represents a hydrogen atom, a linear alkyl group having 1 to 8 carbon atoms, or a branched alkyl group having 3 to 8 carbon atoms. is preferred.

[0037] R in formula (3-2) 16 and R 17 are not particularly limited, but are preferably each independently a hydrogen atom, a linear alkyl group having 1 to 8 carbon atoms or a branched alkyl group having 3 to 8 carbon atoms, a linear or branched alkoxy group having 4 to 8 carbon atoms (which may be interrupted by an aryl ring), a linear or branched fatty acid ester group having 6 to 18 carbon atoms, or a substituent represented by the above formula (d).

[0038] R in formula (3-3) 18 is not particularly limited, but is preferably a hydrogen atom, a linear alkyl group having 1 to 8 carbon atoms, or a branched alkyl group having 3 to 8 carbon atoms.

[0039] R 19 and R 20 are not particularly limited, but each independently represents a hydrogen atom or the following formula (e):

[0040] [ka]

[0041] (In formula (e), R 22 represents a linear alkyl group having 1 to 8 carbon atoms, a branched alkyl group having 3 to 8 carbon atoms, a linear alkoxy group having 1 to 8 carbon atoms, or a branched alkoxy group having 3 to 8 carbon atoms. A substituent represented by the following formula is preferred. R 19 and R 20 It is more preferable that one of the above is a hydrogen atom and the other is a substituent represented by the above formula (e).

[0042] Suitable, non-limiting examples of anthraquinone dyes that can be used as dichroic dyes other than the anthraquinone compounds represented by general formula (1) and the anthraquinone compounds represented by general formula (2) are shown in Tables 1 to 4 below.

[0043] [Table 1]

[0044] [Table 2]

[0045] [Table 3]

[0046] [Table 4]

[0047] Suitable, non-limiting examples of azo dyes used as dichroic dyes other than the anthraquinone compounds represented by general formula (1) and the anthraquinone compounds represented by general formula (2) include compounds represented by the following general formula (4).

[0048] [ka]

[0049] A1 is not particularly limited, but may be a hydrogen atom, -CO2A3, a linear or branched alkyl group having 4 to 8 carbon atoms, or a substituent represented by the following formula (f), (g), or (h):

[0050] [ka]

[0051] (In formula (f), A4 represents a linear alkoxy group having 1 to 8 carbon atoms or a branched alkoxy group having 3 to 8 carbon atoms. In addition, A5 in formulas (g) and (h) represents a linear alkyl group having 1 to 8 carbon atoms or a branched alkyl group having 3 to 8 carbon atoms.) is preferred. Furthermore, A3 in formula (4) is preferably a linear alkyl group having 1 to 8 carbon atoms or a branched alkyl group having 3 to 8 carbon atoms.

[0052] A2 is not particularly limited, but may be a substituent represented by the following formula (i), (j) or (k):

[0053] [ka]

[0054] (In formula (i), A6 represents a linear alkyl group having 1 to 8 carbon atoms. In formulas (j) and (k), A7 and A8 each independently represent a 1,4-phenylene group or a 1,4-naphthalenediyl group, A9 represents a linear alkoxy group having 1 to 8 carbon atoms, L1 represents -N=N- or -N=CH-, and L2 represents -O- or -O-CO-.) is preferred.

[0055] Suitable, non-limiting specific examples of azo dyes that can be used as dye compounds other than the anthraquinone compounds represented by general formula (1) and the anthraquinone compounds represented by general formula (2) are shown in Tables 5 and 6.

[0056] [Table 5]

[0057] [Table 6]

[0058] When a dichroic dye other than the anthraquinone compound represented by the general formula (1) and the anthraquinone compound represented by the general formula (2) is used in combination, the content of the compounds represented by the general formula (1) and the general formula (2) in the total dichroic dye is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more.

[0059] The combination of the anthraquinone compounds represented by the general formula (1), the general formula (2), the general formula (3-1), the general formula (3-2), and the general formula (3-3) is not particularly limited, but a preferred combination is an anthraquinone compound represented by the general formula (1) in which R1 is an alkyl group having 4 to 8 carbon atoms (Nos. 1, 2, 4, 5, 19, and 20), an anthraquinone compound represented by the general formula (2) in which R5 is an alkyl group having 4 to 10 carbon atoms (Nos. 101, 102, and 105), an anthraquinone compound represented by the general formula (3-1) No. 202, and an anthraquinone compound represented by the general formula (3-2) Nos. 213, 215, and 220.

[0060] The liquid crystal composition may further contain light stabilizers such as benzotriazoles, benzophenones, and hindered amines, antioxidants such as phosphites and hindered phenols, thermal polymerization inhibitors, thiol compounds, photosensitizers, photosensitizers, chain transfer inhibitors, polymerization inhibitors, adhesion promoters, antifoaming agents, crosslinking agents, surfactants, thermosetting accelerators, thermoplastic resins, thermosetting resins, thickeners such as urethane diacrylate, etc. Furthermore, spherical or cylindrical spacers made of silica, glass, plastic, ceramic, etc. may be added to control the cell gap as a light-controlling element. In this case, the cell gap can be set in the range of 2 to 100 μm.

[0061] For example, a photocurable compound and a photopolymerization initiator can be added to a liquid crystal composition, as exemplified in Patent Document 4. By photocuring a liquid crystal composition containing these components, the polymer and the liquid crystal substance are phase-separated, and a film having a light-controlling layer can be obtained.

[0062] In this case, the photocurable compound having a functional group polymerizable by the action of a photopolymerization initiator is not particularly limited, but examples thereof include compounds having a (meth)acrylate group, compounds having a vinyl group, and compounds having an allyl group. Compounds having a (meth)acrylate group are preferred. The photocurable compound may be used alone or as a mixture of two or more. It is more preferred to use both a mono(meth)acrylate compound having one (meth)acrylate group in one molecule and a di(meth)acrylate compound having two (meth)acrylate groups in one molecule in combination. In this specification, the term "(meth)acrylate" means "methacrylate and / or acrylate."

[0063] The mono(meth)acrylate compound is preferably a mono(meth)acrylate having a linear or branched alkyl group having 5 to 13 carbon atoms, and specific examples thereof include linear alkyl mono(meth)acrylates such as pentyl(meth)acrylate, hexyl(meth)acrylate, heptyl(meth)acrylate, octyl(meth)acrylate, nonyl(meth)acrylate, decyl(meth)acrylate, undecyl(meth)acrylate, dodecyl(meth)acrylate, and tridecyl(meth)acrylate, and branched alkyl mono(meth)acrylates such as 2-methylhexyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, 2-propylhexyl(meth)acrylate, 2-methylheptyl(meth)acrylate, 2-ethylheptyl(meth)acrylate, and 2-propylheptyl(meth)acrylate.

[0064] Suitable examples of the di(meth)acrylate compound 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, and 1,13-tridecanediol di(meth)acrylate.

[0065] The photopolymerization initiator that can be contained in the liquid crystal composition is not particularly limited as long as it is a compound that can polymerize a photocurable compound by irradiation with light. As the photopolymerization initiator, one that remains in the cured liquid crystal composition after irradiation with light and does not cause deterioration of the dichroic dye, etc. is preferred. The photopolymerization initiator may be used alone or as a mixture of two or more types. As the photopolymerization initiator, for example, alkylphenone-based photopolymerization initiators such as Darocur 1173, Irgacure 651, and Irgacure 184, and phosphine oxide-based photopolymerization initiators such as Irgacure TPO are preferably used.

[0066] The light-adjusting element comprises a pair of substrates, at least one of which is a transparent substrate having a transparent electrode, and a layer of the liquid crystal composition according to any of the above embodiments or a photocured product thereof sandwiched between them. Examples of the substrate include inorganic transparent materials such as glass and quartz, and colorless, transparent, or opaque materials such as metals, metal oxides, semiconductors, ceramics, and plastic plates and films. The electrodes are formed on the substrate by applying a thin film of, for example, a metal oxide, metal, semiconductor, or organic conductive material to the entire surface or a portion of the substrate using a known coating method, printing method, or vapor deposition method such as sputtering. To obtain a particularly large-area light-adjusting 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 using 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-drive electrode substrate, a matrix-drive electrode substrate, or an active-matrix drive electrode substrate. Furthermore, the electrode surface provided on the substrate may be covered entirely or partially with a protective film or alignment film made of organic compounds such as polyimide, polyamide, silicon, and cyanide compounds, inorganic compounds such as SiO2, TiO2, and ZrO2, or mixtures thereof.

[0067] The use of a plastic film as a substrate allows for a flexible and lightweight light-adjusting element to be obtained. Therefore, the light-adjusting 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. Alternatively, the light-adjusting element can be attached to the surface of a single flat or curved glass or hard plastic substrate using double-sided tape or adhesive. The light-adjusting element may 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-adjusting element, or a color filter or polarizer filter may be laminated thereon. Furthermore, the light-adjusting element may be laminated as an electroluminescent display element, a light-emitting diode display element, an electrochromic display element, or another liquid crystal display element.

[0068] The driving device for applying voltage to the dimming element is a device that can apply DC or AC voltage and that opens or shorts the electrodes when no voltage is applied. This driving device may also be equipped with a voltage application circuit for segment driving, a voltage application circuit for matrix driving, a voltage application circuit for active matrix driving, etc.

[0069] Such a light-adjusting element has a neutral color, little color leakage in the visible light range, and excellent contrast, and is therefore ideal for use in vehicles or as a building material. [Example]

[0070] The present invention will be described in more detail below by way of examples, but these are merely illustrative and do not limit the present invention in any way. In the text, "parts" and "%" are by mass unless otherwise specified. The maximum absorption wavelength in the examples is a value measured using a spectrophotometer "UV-3150 manufactured by Shimadzu Corporation."

[0071] Example 1 (Preparation of Liquid Crystal Composition of the Present Invention) As the (B) liquid crystal material, 0.51 parts of 1-cyano-4'-n-pentylbiphenyl, 0.25 parts of 1-cyano-4'-n-heptylbiphenyl, 0.16 parts of 1-cyano-4'-n-octyloxybiphenyl, and 0.08 parts of 1-cyano-4''-n-pentylterphenyl, and as the (A) dye compound, 0.0120 parts of the compound represented by Specific Example No. 2 and 0.0180 parts of the compound represented by Specific Example No. 101 were stirred on a hot plate at 70°C for 1 hour to prepare a liquid crystal composition of the present invention (the content of the (A) dye compound relative to the total amount of the (B) liquid crystal material was approximately 3.0% by mass).

[0072] Example 2 (Preparation of Liquid Crystal Composition of the Present Invention) As the (B) liquid crystal materials, 0.51 parts of 1-cyano-4'-n-pentylbiphenyl, 0.25 parts of 1-cyano-4'-n-heptylbiphenyl, 0.16 parts of 1-cyano-4'-n-octyloxybiphenyl, and 0.08 parts of 1-cyano-4''-n-pentylterphenyl, and as the (A) dye compounds, 0.0104 parts of the compound represented by Specific Example No. 1, 0.0147 parts of the compound represented by Specific Example No. 102, and 0.0049 parts of the compound represented by Specific Example No. 215 were stirred on a hot plate at 70°C for 1 hour to prepare a liquid crystal composition of the present invention (the content of the (A) dye compound relative to the total amount of the (B) liquid crystal material was approximately 3.0% by mass).

[0073] Example 3 (Preparation of Liquid Crystal Composition of the Present Invention) As the (B) liquid crystal materials, 0.51 parts of 1-cyano-4'-n-pentylbiphenyl, 0.25 parts of 1-cyano-4'-n-heptylbiphenyl, 0.16 parts of 1-cyano-4'-n-octyloxybiphenyl, and 0.08 parts of 1-cyano-4''-n-pentylterphenyl, and as the (A) dye compounds, 0.0104 parts of the compound represented by Specific Example No. 2, 0.0147 parts of the compound represented by Specific Example No. 102, and 0.0049 parts of the compound represented by Specific Example No. 220 were stirred on a hot plate at 70°C for 1 hour to prepare a liquid crystal composition of the present invention (the content of the (A) dye compound relative to the total amount of the (B) liquid crystal material was approximately 3.0% by mass).

[0074] Example 4 (Preparation of Liquid Crystal Composition of the Present Invention) As (B) liquid crystal materials, 0.51 parts of 1-cyano-4'-n-pentylbiphenyl, 0.25 parts of 1-cyano-4'-n-heptylbiphenyl, 0.16 parts of 1-cyano-4'-n-octyloxybiphenyl, and 0.08 parts of 1-cyano-4''-n-pentylterphenyl, and as (A) dye compounds, 0.0122 parts of the compound represented by Specific Example No. 2, 0.0147 parts of the compound represented by Specific Example No. 102, and 0.0031 parts of the compound represented by Specific Example No. 202 were stirred on a hot plate at 70°C for 1 hour to prepare a liquid crystal composition of the present invention (the content of the (A) dye compound relative to the total amount of the (B) liquid crystal material was approximately 3.0% by mass).

[0075] Example 5 (Preparation of Liquid Crystal Composition of the Present Invention) As the (B) liquid crystal materials, 0.51 parts of 1-cyano-4'-n-pentylbiphenyl, 0.25 parts of 1-cyano-4'-n-heptylbiphenyl, 0.16 parts of 1-cyano-4'-n-octyloxybiphenyl, and 0.08 parts of 1-cyano-4''-n-pentylterphenyl, and as the (A) dye compounds, 0.0104 parts of the compound represented by Specific Example No. 2, 0.0147 parts of the compound represented by Specific Example No. 101, and 0.0049 parts of the compound represented by Specific Example No. 220 were stirred on a hot plate at 70°C for 1 hour to prepare a liquid crystal composition of the present invention (the content of the (A) dye compound relative to the total amount of the (B) liquid crystal material was approximately 3.0% by mass).

[0076] Example 6 (Preparation of Liquid Crystal Composition of the Present Invention) As (B) liquid crystal materials, 0.51 parts of 1-cyano-4'-n-pentylbiphenyl, 0.25 parts of 1-cyano-4'-n-heptylbiphenyl, 0.16 parts of 1-cyano-4'-n-octyloxybiphenyl, and 0.08 parts of 1-cyano-4''-n-pentylterphenyl, and as (A) dye compounds, 0.0104 parts of Specific Example No. 10 compound, 0.0147 parts of Specific Example No. 102 compound, and 0.0049 parts of Specific Example No. 213 compound were stirred on a hot plate at 70°C for 1 hour to prepare a liquid crystal composition of the present invention (the content of the (A) dye compound relative to the total amount of the (B) liquid crystal material was approximately 3.0% by mass).

[0077] Comparative Example 1 (Preparation of Comparative Liquid Crystal Composition) A liquid crystal composition of the present invention (the content of the (A) dye compound relative to the total amount of the (B) liquid crystal material) (the content of the (A) dye compound is approximately 3.0% by mass) was prepared in the same manner as in Example 1, except that the (A) dye compound was changed to 0.0104 parts of the compound represented by the following formula (X) disclosed in WO2022 / 138440, 0.0147 parts of the compound represented by the following formula (Y) disclosed in WO2022 / 158493, and 0.0049 parts of the compound represented by specific example No. 213.

[0078] [ka]

[0079] Comparative Example 2 (Preparation of Comparative Liquid Crystal Composition) A liquid crystal composition of the present invention (the content of the (A) dye compound relative to the total amount of the (B) liquid crystal material) (the content of the (A) dye compound is approximately 3.0 mass % with respect to the total amount of the (B) liquid crystal material) was prepared in the same manner as in Example 1, except that the (A) dye compound was changed to 0.0104 parts of the compound represented by the following formula (Z) disclosed in JP-B-03-063489, 0.0147 parts of the compound represented by the above formula (Y) disclosed in WO2022 / 158493, and 0.0049 parts of the compound represented by Specific Example No. 213.

[0080] [ka]

[0081] Example 7 (Preparation of light-controlling elements of the present invention and comparative examples) The liquid crystal composition obtained in Example 1 was sealed in a device with a gap of 15 μm between two glass substrates, each having a transparent electrode and a surface in contact with the liquid crystal that had been subjected to a homogeneous alignment treatment by rubbing a polyamide resin, to obtain a light-control device. In the light-control device, the liquid crystal was in a homogeneous alignment state when no voltage was applied, and the dye molecules were also in a similar alignment state according to the liquid crystal.

[0082] Examples 8 to 12 (Fabrication of the light-adjusting element of the present invention) A light control device of the present invention was prepared in the same manner as in Example 7, except that the liquid crystal composition obtained in each of Examples 2 to 6 was used instead of the liquid crystal composition obtained in Example 1.

[0083] Comparative Examples 3 and 4 (Fabrication of Comparative Light-Controlling Devices) Comparative light-controlling elements were prepared in the same manner as in Example 7, except that the liquid crystal compositions obtained in Comparative Examples 1 and 2 were used instead of the liquid crystal composition obtained in Example 1.

[0084] [Evaluation method] The physical properties of the light-adjustable elements obtained in Examples 7 to 12 and Comparative Examples 3 and 4 were measured and evaluated as follows.

[0085] (Transmittance measurement of photochromic element) The transmittance (Kz) of linearly polarized light parallel to the alignment direction and the transmittance (Ky) of linearly polarized light perpendicular to the alignment direction were measured for the light control elements obtained in Examples 7 to 12 and Comparative Example 4 using a spectrophotometer (Hitachi, Ltd., U-4100). The measurements were carried out over a wavelength range of 400 to 700 nm.

[0086] (Kz(Y) after luminosity correction, Ky(Y) after luminosity correction) For the light-control devices obtained in Examples 7 to 12 and Comparative Example 4, the transmittance Kz for linearly polarized light parallel to the alignment direction, corrected for luminosity (Kz(Y)(%)), and the transmittance Ky for polarized light perpendicular to the alignment direction, corrected for luminosity (Ky(Y)(%)), were calculated. The luminosity-corrected Kz(Y)(%) and luminosity-corrected Ky(Y)(%) are transmittances corrected to luminosity according to JIS Z 8722:2009 for Ky and Kz at each wavelength, determined at predetermined wavelength intervals dλ (5 nm in this example) in the wavelength range of 400 to 700 nm. Specifically, the Kz and Ky values ​​for each wavelength were calculated by substituting them into the following formulas (I and II). In the formulas (I and II), Pλ represents the spectral distribution of standard light (illuminant C), and yλ represents the 2-degree visual field color matching function.

[0087]

number

[0088] (Calculating the dichroic ratio of the dimming element) For the light-control elements obtained in Examples 7 to 12 and Comparative Example 4, the dichroic ratio after luminosity correction in the range of 400 to 700 nm was calculated by calculating the absorbance ratio from the transmittance Kz (Y) (%) for linearly polarized light parallel to the alignment direction, which was corrected for luminosity, and the transmittance Ky (Y) (%) for polarized light perpendicular to the alignment direction, which was corrected for luminosity, using the following formula (III): Table 7 shows the results.

[0089]

number

[0090] [Table 7]

[0091] As shown in Table 7, it was confirmed that the light control devices of Examples 7 to 12 exhibited better dichroic ratios than the light control device of Comparative Example 4.

[0092] (Light resistance test of dimming element) A UV cut filter of 400 nm or less was attached to the light control elements obtained in Examples 7 to 12 and Comparative Example 3, and the light was then measured at an illuminance of 650 W / m under a condition of 63°C. 2 The light resistance test was carried out by irradiating the light-controlling element with a metal halide lamp for 300 hours. The transmittance in the range of 380 to 780 nm was measured with a spectrophotometer before and after the light resistance test, both when no voltage was applied and when a voltage (48 V) was applied. From the obtained transmission spectrum, the chromaticity (L * , a * , b * ) was calculated, and the color difference (ΔE ab ) was calculated using the following formula (iv): ab The smaller the value, the smaller the color change before and after the light resistance test, and the more excellent the light resistance. The results are shown in Table 8. ΔE ab (L * , a * , b * )={(ΔL * ) 2 +(Δa * ) 2 +(Δb * ) 2} 1 / 2 (iv)

[0093] [Table 8]

[0094] As shown in Table 8, the light control elements of Examples 7 to 12 had a lower ΔE than the light control element of Comparative Example 3 both when a voltage was applied and when no voltage was applied. ab It was confirmed that the light resistance was small and excellent.

[0095] (Hue a when voltage is applied to the dimming element * value, b * value) The transmittance of the light-controlling elements obtained in Examples 7 to 12 and Comparative Examples 3 and 4 was measured using a spectrophotometer, and the hue a was calculated in accordance with JIS Z 8781-4:2013. * value, b * The values ​​are shown in Table 9.

[0096] [Table 9]

[0097] As shown in Table 9, the dimming elements of Examples 7 to 12 * value, b * Both values ​​were less than 5, indicating achromaticity. Therefore, it was confirmed that the performance of the photochromic elements of Examples 7 to 12 was significantly improved compared to the photochromic elements of Comparative Examples 3 and 4 in that all of the properties of dichroism, light resistance, and achromatic color were well balanced and excellent. [Industrial Applicability]

[0098] By using the liquid crystal composition of the present invention, a light-controlling liquid crystal device having a high dichroic ratio, an achromatic color, and excellent light resistance can be obtained. Such a light-controlling device can be suitably used for outdoor building materials and vehicle applications, which require high durability, a dichroic ratio, and designability.

Claims

1. A liquid crystal composition comprising (A) a dye compound and (B) a liquid crystal material, wherein the dye compound (A) is represented by the following general formula (1): 【Chemical 1】 (In the formula, R １ represents a linear alkyl group having 1 to 12 carbon atoms. ２ , R ３ are each independently a hydrogen atom, a linear alkoxy group having 4 to 10 carbon atoms, or a group represented by the following formula (a): 【Chemistry 2】 (In formula (a), R ４ represents a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms. ４ When there are multiple, they may be the same or different. An anthraquinone compound represented by the formula: The following general formula (2) 【Chemistry 3】 (In the formula, R ５ represents a hydrogen atom or an alkyl group having 4 to 10 carbon atoms. ６ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. A liquid crystal composition comprising an anthraquinone compound represented by the formula:

2. 2. The liquid crystal composition according to claim 1, wherein the mass ratio of the anthraquinone compound represented by the general formula (1) to the anthraquinone compound represented by the general formula (2) is 2:1 to 1:

2.

3. 2. The liquid crystal composition according to claim 1, wherein the concentration of the dye compound (A) contained in the liquid crystal composition relative to the liquid crystal material (B) is 0.5 to 10% by mass.

4. 2. The liquid crystal composition according to claim 1, comprising the anthraquinone compound represented by the general formula (1) and a dichroic dye other than the anthraquinone compound represented by the general formula (2).

5. A light-adjusting element comprising a pair of opposing substrates, at least one of which is a transparent substrate having a transparent electrode, and the liquid crystal composition according to claim 1 sandwiched between the pair of substrates.

6. 6. The light-adjusting element according to claim 5, wherein both of the pair of substrates are transparent substrates having transparent electrodes.

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