Liquid crystal composition containing anthraquinone compound, and dimming element

Abstract

To provide a liquid crystal composition that is excellent in light resistance, and a dimming element containing the composition.SOLUTION: The liquid crystal composition contains (A) a dye compound and (B) a liquid crystal material, where the dye compound (A) contains multiple types of anthraquinone compounds with specific structures.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a liquid crystal composition and a light-adjusting element containing an anthraquinone compound. [Background technology]

[0002] For purposes such as privacy protection, light-controlling panels have become commonplace in windows, doors, and partitions in vehicles such as trains and automobiles, and buildings such as business buildings and hospitals. These panels include films obtained by dispersing liquid crystals in polymers and films with a light-controlling layer formed by utilizing the phase separation of a liquid crystal material upon photocuring of a composition containing a photocurable compound and a liquid crystal. While such light-controlling panels typically block the view by controlling the transmission and scattering of light depending on whether or not a voltage is applied, they do not block light and tend 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. For example, when using such light-controlling panels in automobile windows, they are required to provide clear visibility without fogging when transparent, high contrast, and light resistance that does not decrease transmittance even when exposed to light at high temperatures for long periods of time due to long-term exposure to light during outdoor use. This has led to an increasing demand for black elements that can block visible light from the perspectives of practicality and design.

[0003] In order to satisfy the above market demands, various liquid crystal display elements called GH (guest-host) type, which use liquid crystal compositions containing dyes, have been proposed. These liquid crystal display elements, which are characterized by their viewing angle, brightness, etc., have also been put to practical use in automotive applications and as light control elements.

[0004] Dichroic dyes commonly used in liquid crystal compositions for light-adjusting devices are required to have a dichroic ratio to enhance contrast when used in a device, as well as 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, no dichroic dyes have yet been developed that meet market demands. For example, Patent Documents 4 and 5 disclose dichroic dye compositions suitable for light-adjusting applications. However, both exhibit significant hue changes upon prolonged exposure to light, and are not considered to have sufficient light resistance for outdoor use. [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] 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 containing a dye compound having a specific structure, and a light-adjusting element having excellent light resistance. [Means for solving the problem]

[0007] As a result of extensive research, the present inventors have discovered that the above problems can be solved by using a liquid crystal composition containing multiple anthraquinone compounds (dichroic dyes) with specific structures, and have thus completed the present invention. That is, the present invention provides: (1) A liquid crystal composition containing (A) a dye compound and (B) a liquid crystal material, The (A) dye compound is an anthraquinone compound represented by the following general formula (1), and A liquid crystal composition containing an anthraquinone compound represented by the following general formula (2) and / or (3):

[0008] [ka] (In the formula, R1 represents a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms, and R2 represents a branched alkyl group having 3 to 16 carbon atoms.)

[0009] [ka] (wherein R3 represents a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms).

[0010] [ka] (wherein R4 represents a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms). (2) The liquid crystal composition according to (1), wherein the concentration of the dye compound (A) contained in the liquid crystal composition relative to the liquid crystal material (B) is 0.1 to 5.0% by mass. (3) A light-adjusting element comprising a pair of opposing substrates, at least one of which is a transparent substrate having a transparent electrode, and a liquid crystal composition according to (1) or (2) sandwiched between the pair of substrates. [Effects of the Invention]

[0011] By using the liquid crystal composition of the present invention, a light-controlling element having excellent light-shielding properties can be obtained. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described in detail below. The liquid crystal composition of the present invention (hereinafter also simply referred to as "the composition of the present invention") contains an anthraquinone compound represented by the following formula (1), and formula (2) and / or formula (3). The anthraquinone compounds represented by formulas (1) to (3) contained in the composition of the present invention function as dichroic dyes in the composition of the present invention.

[0013] [ka] (wherein R1 represents a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms, and R2 represents a branched alkyl group having 3 to 16 carbon atoms), and

[0014] [ka] (wherein R3 represents a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms).

[0015] [ka] (wherein R4 represents a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms).

[0016] Examples of the linear or branched alkyl group having 1 to 8 carbon atoms represented by R1 in formula (1) include a methyl group, an ethyl group, a 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 neo-pentyl group, a t-pentyl group, a hexyl group, a heptyl group, an octyl 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. A linear or branched alkyl group having 1 to 8 carbon atoms is preferred, and a linear or branched alkyl group having 1 to 4 carbon atoms is more preferred.

[0017] In formula (1), R2 represents a branched alkyl group having 3 to 16 carbon atoms. Specific examples of the branched alkyl group having 3 to 16 carbon atoms represented by R2 in formula (1) 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 2-methyloctyl group, a 2-methylnonyl group, a 3-methylbutyl group, a 3-methylpentyl group, a 3-methylhexyl group, a 3-methylheptyl group, a 3-methyloctyl group, a 3 ...hexyl group, a 3-methyloctyl group, a 3-methylnonyl group, a 3-methylbutyl group, a 3-methylpentyl group, a 3-methylhexyl group, a 3-methylheptyl group, a 3-methyloctyl group, a 3-methylnonyl group, a 3-methylbutyl group, a 3-methyloctyl group, a 3- 2-methyloctyl group, 2-ethylpropyl group, 2-ethylbutyl group, 2-ethylhexyl group, 2-ethylheptyl group, 2-propylhexyl group, 2-butylhexyl group, 2-pentylhexyl group, 2-pentylheptyl group, 2-pentyloctyl group, 2-pentylnonyl group, 2-pentyldecyl group, 2-hexylpentyl group, 2-hexylnonyl group, and 2-hexyldecyl group, and a branched alkyl group having 6 to 16 carbon atoms is preferred.

[0018] In formula (2), R3 represents a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms. Specific examples of the linear or branched alkyl group having 1 to 8 carbon atoms represented by R3 in formula (2) include the same linear or branched alkyl groups as those described in the section on specific examples of the alkyl group having 1 to 8 carbon atoms represented by R1 in formula (1), and linear or branched alkyl groups having 1 to 4 carbon atoms are preferred.

[0019] In formula (3), R4 represents a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms. Specific examples of the linear or branched alkyl group having 1 to 8 carbon atoms represented by R4 in formula (3) include the same linear or branched alkyl groups as those described in the section on specific examples of the alkyl group having 1 to 8 carbon atoms represented by R1 in formula (1), and linear or branched alkyl groups having 1 to 4 carbon atoms are preferred.

[0020] The compounds represented by formulas (1) and (2) can be synthesized by conventionally known methods, for example, as described in WO2022 / 191169. Specifically, 1,5-dichloroanthraquinone and 4-hydroxybenzenethiol are reacted in a solvent such as DMF under basic conditions such as potassium carbonate, and then reacted with a benzenethiol derivative represented by the following formula (4) in a solvent such as DMF under basic conditions such as potassium carbonate to obtain a compound represented by formula (2). In addition, the compound of formula (1) can be obtained by reacting the compound of formula (5), which is synthesized by the same method as the compound of formula (2), with an alkanoyl chloride of formula (6) in a solvent such as toluene under basic conditions such as triethylamine. In addition, R3 in the following formula (4), R1 in the formula (5), and R2 in the formula (6) have the same meanings as R1, R2, and R3 in the formulas (1) and (2).

[0021] [ka]

[0022] The compound represented by formula (3) can be synthesized by the method described in WO2021 / 261181, etc. Specifically, 1,5-dichloroanthraquinone is reacted with a benzenethiol derivative represented by the following formula (7) in a solvent such as DMF under basic conditions such as potassium carbonate to obtain a compound represented by formula (3). In addition, R4 in the following formula (7) has the same meaning as R4 in formula (3).

[0023] [ka]

[0024] In the composition of the present invention, the dye compound (A) contains at least one compound represented by formula (2) or (3), and may contain a plurality of compounds.

[0025] In the composition of the present invention, the dye compound (A) may be used in combination with a dichroic dye other than the anthraquinone compounds represented by formulas (1) to (3). 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, and it is more preferable to use an azo dye or an anthraquinone dye in combination.

[0026] The content of the anthraquinone compound represented by formula (1) in the total dichroic dye is not particularly limited as long as it is within a range that does not impair the effects of the present invention, but is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more. By setting the content of formula (1) within this range, a liquid crystal composition with high light resistance can be obtained.

[0027] The liquid crystal material (B) contained in the liquid crystal composition of the present invention is not particularly limited as long as it is a material (compound having liquid crystal properties) having liquid crystallinity such as nematic liquid crystal, cholesteric liquid crystal, smectic liquid crystal, etc. Examples of such liquid crystal compounds include those described in paragraphs 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, Ltd., 1989), and in Japanese Patent Nos. 4,169,692 and 5,659,512.

[0028] The total concentration of the (A) dye compound contained in the liquid crystal composition is preferably 0.1 to 5.0 mass %, more preferably 0.1 to 3.0 mass %, relative to the (B) liquid crystal material. By setting the concentration of the (A) dye compound within this range, a sufficient dye addition effect can be obtained, and a liquid crystal composition with high light resistance can be obtained.

[0029] In order to achieve the above-mentioned preferred dye concentration, the solubility of the dye compound (A) in the liquid crystal material (B) is preferably 0.1% by mass or more, and more preferably 0.3% by mass or more.

[0030] The liquid crystal composition of the present invention may contain various additives such as an optically active substance that exhibits or does not exhibit a liquid crystal phase, such as cholesteryl noenoate, an ultraviolet absorber, and an antioxidant.

[0031] The liquid crystal composition of the present invention may further contain in combination a light stabilizer such as a benzotriazole-based, benzophenone-based or hindered amine-based, an antioxidant such as a phosphite-based or hindered phenol-based, a thermal polymerization inhibitor, a thiol compound, a photosensitizer, a photosensitizer, a chain transfer inhibitor, a polymerization inhibitor, an adhesion promoter, an antifoaming agent, a crosslinking agent, a surfactant, a heat curing accelerator, a thermoplastic resin, a thermosetting resin, a thickener such as urethane diacrylate, and the like. In order to control the cell gap of the light-adjusting element, spherical or cylindrical spacers made of silica, glass, plastic, ceramic, etc. may be added. In this case, the cell gap can be set in the range of 2 to 100 μm.

[0032] As an example of the additives that may be contained, a photocurable compound and a photopolymerization initiator may be contained, as described in Patent Document 4. By photocuring these, the polymer and the liquid crystal substance undergo phase separation, and a film having a light control layer or the like can be obtained.

[0033] In this case, examples of compounds having a functional group polymerizable by the action of a photopolymerization initiator include compounds having a (meth)acrylate group, compounds having a vinyl group, and compounds having an allyl group, but compounds having a (meth)acrylate group are preferred. That is, it is more preferable to use in combination 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 this specification, the term "(meth)acrylate" means "methacrylate and / or acrylate".

[0034] 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.

[0035] 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.

[0036] The photopolymerization initiator is not particularly limited as long as it is a compound that can polymerize a photocurable compound by irradiation with light, but it is preferable that it does not remain in the cured liquid crystal composition after irradiation with light and cause deterioration of the dichroic dye, etc. 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.

[0037] The liquid crystal composition of the present invention can be obtained by mixing and stirring (A) the dye compound, (B) the liquid crystal material, and any optional components added as needed. While the simplest method for mixing and stirring is to simply place all of the components in a container and stir manually, it is more effective to use an electric stirrer such as a magnetic stirrer. Mixing and stirring while heating can also effectively dissolve (A) the dye compound.

[0038] The light-adjusting element of the present invention comprises a pair of substrates, at least one of which is a transparent substrate having a transparent electrode, sandwiched between the liquid crystal composition or a photocured product thereof. 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 substrates by coating, printing, or vapor deposition methods such as sputtering with a thin film of a metal oxide, metal, semiconductor, or organic conductive material over the entire surface or in part of the substrate using known coating methods, printing, or vapor deposition methods such as sputtering. In particular, to obtain a 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 vapor deposition methods such as sputtering or printing, from the standpoints of productivity and processability. The substrate may also have electrodes or wiring for connecting 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.

[0039] The use of a plastic film as a substrate allows for a flexible and lightweight photochromic element. Therefore, the photochromic 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 photochromic 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 photochromic element 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 photochromic element. A color filter or a polarizer filter may also be laminated. The photochromic element may also be laminated as an electroluminescent display element, a light-emitting diode display element, an electrochromic display element, or another liquid crystal display element.

[0040] The driving device for applying a voltage to the dimming element of the present invention is a device that can apply a DC voltage or an 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.

[0041] The dye compounds (A) of the present invention represented by formula (1) and formulas (2) to (4) have high light-shielding properties, and light-control devices using these compounds are suitable for use in building materials such as windows, partitions, and doors, and in-vehicle materials such as windows and sunroofs. [Example]

[0042] The present invention will be described in more detail below with reference to examples. In the text, "parts" and "%" are by mass unless otherwise specified.

[0043] Example 1 (Synthesis of the anthraquinone compound of the present invention represented by formula (2)) According to the method described in steps 1 and 2 of Example 3 of WO2022 / 191169, a compound represented by the following formula (2-1) was obtained.

[0044] [ka]

[0045] Example 2 (Synthesis of the anthraquinone compound of the present invention represented by formula (1)) According to the method described in step 3 of Example 3 of WO2022 / 191169, a compound represented by the following formula (1-1) was obtained from a compound of formula (2-1).

[0046] [ka]

[0047] Example 3 (Synthesis of the anthraquinone compound of the present invention represented by formula (3)) To 20 parts of DMF were added 5.5 parts of 1,5-dichloroanthraquinone and 8.2 parts of potassium carbonate, and a DMF solution of 7.5 parts of 4-toluenethiol was added dropwise at 25°C, followed by stirring at the same temperature for 4 hours. The precipitate was filtered, washed with water, and dried in a hot air dryer at 80°C for 24 hours to obtain 5.8 parts of a compound represented by the following formula (3-1).

[0048] [ka]

[0049] Example 4 (Synthesis of the anthraquinone compound of the present invention represented by formula (1)) According to the method described in Example 2 of WO2022 / 191169, a compound represented by the following formula (1-2) was obtained.

[0050] [ka]

[0051] Example 5 (Synthesis of the anthraquinone compound of the present invention represented by formula (3)) The same procedure as in Example 2 was carried out except that 10.0 parts of 4-t-butylbenzenethiol was used instead of 7.5 parts of 4-toluenethiol, to obtain 6.5 parts of a compound represented by the following formula (3-2).

[0052] [ka]

[0053] Example 6 (Synthesis of the anthraquinone compound of the present invention represented by formula (1)) 3.1 parts of a compound represented by the following formula (1-3) were obtained in the same manner as in Example 3 of WO2022 / 191169, except that 3.3 parts of 2-hexyldecanoyl chloride was used instead of 2.2 parts of 2-ethylhexanoyl chloride.

[0054] [ka]

[0055] Example 7 (Preparation of Liquid Crystal Composition of the Present Invention) A liquid crystal composition of the present invention was obtained by mixing 0.0225 parts of the compound represented by formula (1-1) obtained in Example 2, 0.0025 parts of the compound represented by formula (2-1) obtained in Example 1, 0.4970 parts of 1-cyano-4'-n-pentylbiphenyl, 0.2440 parts of 1-cyano-4'-n-heptylbiphenyl, 0.1560 parts of 1-cyano-4'-n-octyloxybiphenyl, and 0.0780 parts of 1-cyano-4''-n-pentylterphenyl at room temperature.

[0056] Example 8 (Preparation of Liquid Crystal Composition of the Present Invention) A liquid crystal composition of the present invention was obtained in accordance with Example 7, except that 0.0220 parts of the compound represented by formula (1-1) and 0.0030 parts of the compound represented by formula (3-1) obtained in Example 3 were used instead of the combination of the compound represented by formula (1-1) and the compound represented by formula (2-1).

[0057] Example 9 (Preparation of Liquid Crystal Composition of the Present Invention) A liquid crystal composition of the present invention was obtained in accordance with Example 7, except that 0.0220 parts of the compound represented by formula (1-2) obtained in Example 4 and 0.0030 parts of the compound represented by formula (3-2) obtained in Example 5 were used instead of the combination of the compound represented by formula (1-1) and the compound represented by formula (2-1).

[0058] Example 10 (Preparation of Liquid Crystal Composition of the Present Invention) A liquid crystal composition of the present invention was obtained in accordance with Example 7, except that 0.0225 parts of the compound represented by formula (1-3) obtained in Example 6 and 0.0025 parts of the compound represented by formula (2-1) were used instead of the combination of the compound represented by formula (1-1) and the compound represented by formula (2-1).

[0059] Comparative Example 1 (Preparation of Comparative Liquid Crystal Composition) A comparative liquid crystal composition was obtained in accordance with Example 7, except that 0.025 parts of the compound represented by formula (1-1) was used instead of the combination of the compound represented by formula (1-1) and the compound represented by formula (2-1).

[0060] Comparative Example 2 (Preparation of Comparative Liquid Crystal Composition) A comparative liquid crystal composition was obtained in accordance with Example 7, except that 0.025 parts of the compound represented by formula (1-2) was used instead of the combination of the compound represented by formula (1-1) and the compound represented by formula (2-1).

[0061] Comparative Example 3 (Preparation of Comparative Liquid Crystal Composition) A comparative liquid crystal composition was obtained in accordance with Example 7, except that 0.025 parts of the compound represented by formula (1-3) was used instead of the combination of the compound represented by formula (1-1) and the compound represented by formula (2-1).

[0062] Example 11 (Fabrication of the light-adjusting element of the present invention) The liquid crystal composition obtained in Example 7 was sealed in a device with a gap of 15 μm between two glass substrates, each having a transparent electrode and having a surface in contact with the liquid crystal that had been subjected to a homogeneous alignment treatment by rubbing a polyamide resin.In the device obtained above, the liquid crystal was in a homogeneous alignment state when no voltage was applied.

[0063] Examples 12 to 14 and Comparative Examples 4 to 6 (Preparation of light-controlling elements of the present invention and comparative examples) The light-controlling elements of the present invention and for comparison were prepared in accordance with Example 11, except that the liquid crystal composition obtained in Example 7 was replaced with the liquid crystal compositions obtained in Examples 8 to 10 and Comparative Examples 1 to 3, respectively.

[0064] (Light resistance test of dimming element) The light control elements obtained in Examples 11 to 14 and Comparative Examples 4 to 6 were subjected to a temperature of 63°C and an illuminance of 650 W / m 2The light resistance test was carried out by irradiating the light-controlling element with a metal halide lamp for 300 hours. The transmittance of the light-controlling element in the range of 300 to 800 nm was measured using a spectrophotometer before and after the light resistance test. The chromaticity (L * , a * , b * ) and calculate the color difference (ΔE ab ) was calculated using the following formula (A). ab The smaller the value, the smaller the color change before and after the light resistance test, meaning that the light resistance is excellent. The results are shown in Table 1. ΔE ab (L * , a * , b * )={(ΔL * ) 2 +(Δa * ) 2 +(Δb * ) 2} 1 / 2 Formula (A)

[0065] As shown in Table 1, the light control elements of Examples 11 and 12 had a lower ΔE ab It was confirmed that the light resistance was small and excellent. Furthermore, as shown in Table 2, the light control element of Example 13 has a lower ΔE ab It was confirmed that the light resistance was small and excellent. Furthermore, as shown in Table 3, the light control element of Example 14 had a lower ΔE ab It was confirmed that the light resistance was small and excellent.

[0066] [Table 1]

[0067] [Table 2]

[0068] [Table 3] [Industrial Applicability]

[0069] By using the liquid crystal composition of the present invention, a light-control liquid crystal element having high light-shielding properties can be obtained, and the element can be suitably used for outdoor building materials and vehicle applications where design is required.

Claims

1. A liquid crystal composition containing (A) a dye compound and (B) a liquid crystal material, The dye compound (A) is an anthraquinone compound represented by the following general formula (1), and A liquid crystal composition containing an anthraquinone compound represented by the following general formula (2) and / or (3): 【Chemical 1】 (In the formula, R １ represents a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms; R ２ represents a branched alkyl group having 3 to 16 carbon atoms. 【Chemistry 2】 (In the formula, R ３ represents a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms. 【Chemistry 3】 (In the formula, R ４ represents a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms.

2. 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 0.1 to 5.0% by mass.

3. 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.

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