Anthraquinone compound, liquid crystal composition containing the compound and light-adjusting element

Abstract

The present invention is an anthraquinone compound represented by formula (1) (in the formula, R1 represents a hydrogen atom, a C1-C12 linear or branched alkyl group, or a C1-C12 linear or branched alkoxy group, and R2 represents a substituent represented by: formula (a) (in formula (a), R3 represents a hydrogen atom, a C1-C8 linear or branched alkyl group, a C1-C8 linear or branched alkoxy group, or a substituent represented by -CH2OR4, where R4 represents a C1-C8 linear or branched alkyl group); or formula (b) (in formula (b), R5 represents a hydrogen atom, a C1-C8 linear or branched alkyl group, or a substituent represented by -CH2OR6, where R6 represents a C1-C8 linear or branched alkyl group)).

Description

[Technical Field]

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

[0002] Various light-controlling films that control the transmission of external light have been proposed for the purpose of protecting privacy and other purposes in windows, doors, and partitions in vehicles such as trains and automobiles, and in buildings such as business buildings and hospitals (see Patent Documents 1 and 2). One such light-controlling film uses liquid crystal. Typically, liquid crystal light-controlling films can block the view by controlling the transmission and scattering of light depending on whether or not a voltage is applied, but they cannot block light itself, so light scattering tends to increase glare. Therefore, attempts have been made to use dyes as materials for light-controlling panels with the aim of reducing glare and improving contrast (see Patent Documents 3 and 4). For example, when such light-controlling panels are used in automobile windows, they are required to have a clear, non-cloudy view when transparent, a deep color when light is blocked, 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, and electrical heat resistance that does not decrease transmittance even when a voltage is applied at high temperatures for long periods of time.

[0003] Dichroic dyes are generally used as dyes in liquid crystal light control films. GH (guest-host) type light control elements using liquid crystal compositions containing dichroic dyes are known, and various dichroic dyes have been proposed (see Patent Documents 5, 6, and 7).

[0004] Such dichroic dyes are required to have not only contrast when used in a display device, but also light fastness and heat resistance when energized. Although efforts have been made to improve these properties, none have been found that satisfy the contrast, light fastness, and heat resistance when energized. For example, Patent Documents 5 to 7 disclose dichroic dyes suitable for light-control applications, but the dyes in these documents are insufficient in contrast, light fastness, and heat resistance when energized. [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 Publication No. 63-72760 [Patent Document 6] Japanese Patent Application Laid-Open No. 62-101657 [Patent Document 7] EP59036A1 Summary of the Invention [Problem to be solved by the invention]

[0006] A first object of the present invention is to provide a novel anthraquinone compound. Another object of the present invention is to provide a dichroic dye which is the novel anthraquinone compound, a liquid crystal composition containing the anthraquinone compound, and a light-controlling device which contains the composition and has excellent contrast, light fastness, and heat resistance when energized. [Means for solving the problem]

[0007] The present inventors have succeeded in obtaining a novel anthraquinone compound having a specific structure. The present inventors have also found that by using a liquid crystal composition containing a dichroic dye that is a novel anthraquinone compound having such a specific structure, a light-controlling element having excellent contrast, light resistance, and heat resistance upon application of electricity can be obtained. That is, the various aspects included in the present invention are as follows. [1].The following formula (1) [ka] (In the formula, R1 represents a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, or a linear or branched alkoxy group having 1 to 12 carbon atoms. R2 represents a compound represented by the following formula (a): [ka] (In formula (a), R3 represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, a linear or branched alkoxy group having 1 to 8 carbon atoms, or a substituent represented by —CH2OR4, and R4 represents a linear or branched alkyl group having 1 to 8 carbon atoms.) or the following formula (b): [ka] (In formula (b), R5 represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a substituent represented by —CH2OR6, and R6 represents a linear or branched alkyl group having 1 to 8 carbon atoms.) represents a substituent represented by An anthraquinone compound represented by the formula: [2] The anthraquinone compound according to the preceding item [1], wherein R2 in formula (1) is a substituent represented by formula (a), and R3 in formula (a) is a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkoxy group having 1 to 8 carbon atoms. [3] The anthraquinone compound according to the above item [2], wherein R3 in formula (a) is a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms. [4]. The anthraquinone compound according to the preceding item [1], wherein R2 in formula (1) is a substituent represented by formula (b), and R5 in formula (b) is a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms. [5] The anthraquinone compound according to any one of the above items [1] to [4], wherein R1 in formula (1) is a linear or branched alkoxy group having 1 to 8 carbon atoms. [6] The anthraquinone compound according to the above item [5], wherein R1 in formula (1) is a linear alkoxy group having 4 to 8 carbon atoms. [7] The anthraquinone compound according to any one of the preceding items [1] to [4], wherein R1 in formula (1) is a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms. [8] The anthraquinone compound according to the above item [7], wherein R1 in formula (1) is a linear alkyl group having 4 to 8 carbon atoms. [9] A liquid crystal composition containing the anthraquinone compound according to any one of the above items [1] to [8] and a liquid crystal material.

[10] The liquid crystal composition according to the above item [9], further comprising a photocurable compound and a photopolymerization initiator.

[11] The liquid crystal composition according to the above item [9] or

[10] , further comprising at least one dye compound other than the anthraquinone compound according to the above item [1].

[12] . A photocured product of the liquid crystal composition according to the preceding item

[10] or

[11] .

[13] A light-controlling 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 any one of [9] to

[11] above or a photocured product according to

[12] above sandwiched between the pair of opposing substrates.

[14] The light-control element according to the above item

[13] , wherein both of the pair of substrates are transparent substrates having transparent electrodes. [Effects of the Invention]

[0008] According to the present invention, a novel anthraquinone compound is provided. Furthermore, by using a liquid crystal composition containing the anthraquinone compound of the present invention, a light-controlling element having excellent contrast, light resistance, and heat resistance upon application of electricity can be obtained. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will be described in detail below. The anthraquinone compound of the present invention is represented by the following formula (1).

[0010] [ka]

[0011] In formula (1), R1 represents a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, or a linear or branched alkoxy group having 1 to 12 carbon atoms. The alkyl group having 1 to 12 carbon atoms represented by R1 in formula (1) may be either linear or branched. Specific examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, neo-pentyl, t-pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, 2-ethylhexyl, 2-propylhexyl, 2-butylhexyl, 2-pentylhexyl, and 2-pentylheptyl. A linear or branched alkyl group having 1 to 8 carbon atoms is preferred, more preferably a linear or branched alkyl group having 4 to 8 carbon atoms, and even more preferably a linear alkyl group having 4 to 8 carbon atoms.

[0012] The alkoxy group having 1 to 12 carbon atoms represented by R1 in formula (1) may be either linear or branched, 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 neo-pentyloxy group, a t-pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group, a decyloxy group, an undecyloxy group, a dodecyloxy group, a 2-ethylhexyloxy group, a 2-propylhexyloxy group, a 2-butylhexyloxy group, a 2-pentylhexyloxy group, and a 2-pentylheptyloxy group. A linear or branched alkoxy group having 1 to 8 carbon atoms is preferred, a linear or branched alkoxy group having 4 to 8 carbon atoms is more preferred, and a linear alkoxy group having 4 to 8 carbon atoms is even more preferred.

[0013] R1 in formula (1) is preferably a linear or branched alkyl group having 1 to 8 carbon atoms or a linear or branched alkoxy group having 1 to 8 carbon atoms, and more preferably a linear alkyl group having 4 to 8 carbon atoms or a linear alkoxy group having 4 to 8 carbon atoms.

[0014] In formula (1), R2 represents a substituent represented by the following formula (a) or (b).

[0015] [ka]

[0016] In formula (a), R3 represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, a linear or branched alkoxy group having 1 to 8 carbon atoms, or a substituent represented by —CH2OR4, and R4 represents a linear or branched alkyl group having 1 to 8 carbon atoms.

[0017] The alkyl group having 1 to 8 carbon atoms represented by R3 in formula (a) may be either linear or branched. Specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, neo-pentyl, t-pentyl, hexyl, heptyl, octyl, and 2-ethylhexyl. A linear or branched alkyl group having 1 to 4 carbon atoms is preferred, and a branched alkyl group having 3 or 4 carbon atoms is more preferred.

[0018] The alkoxy group having 1 to 8 carbon atoms represented by R3 in formula (a) may be either linear or branched. Specific examples thereof include methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, iso-butoxy, sec-butoxy, t-butoxy, n-pentyloxy, iso-pentyloxy, neo-pentyloxy, t-pentyloxy, hexyloxy, heptyloxy, octyloxy, and 2-ethylhexyloxy. A linear or branched alkoxy group having 1 to 4 carbon atoms is preferred, and a branched alkoxy group having 3 or 4 carbon atoms is more preferred.

[0019] R3 in formula (a) is preferably a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkoxy group having 1 to 8 carbon atoms, and more preferably a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms.

[0020] The alkyl group having 1 to 8 carbon atoms represented by R4 in the substituent -CH2OR4 represented by R3 in formula (a) may be either linear or branched. Specific examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, neo-pentyl, t-pentyl, hexyl, heptyl, octyl, and 2-ethylhexyl. A linear or branched alkyl group having 2 to 6 carbon atoms is preferred, and a linear alkyl group having 2 to 6 carbon atoms is more preferred.

[0021] In formula (b), R5 represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a structure represented by -CH2OR6, where R6 represents a linear or branched alkyl group having 1 to 8 carbon atoms.

[0022] The alkyl group having 1 to 8 carbon atoms represented by R5 in formula (b) may be either linear or branched. Specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, neo-pentyl, t-pentyl, hexyl, heptyl, octyl, and 2-ethylhexyl. A linear or branched alkyl group having 1 to 4 carbon atoms is preferred, and a branched alkyl group having 3 or 4 carbon atoms is more preferred.

[0023] R5 in formula (b) is preferably a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms.

[0024] The alkyl group having 1 to 8 carbon atoms represented by R6 in the substituent -CH2OR6 represented by R5 in formula (b) may be either linear or branched. Specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, neo-pentyl, t-pentyl, hexyl, heptyl, octyl, and 2-ethylhexyl. A linear or branched alkyl group having 2 to 6 carbon atoms is more preferred, and a linear alkyl group having 2 to 6 carbon atoms is more preferred.

[0025] As R2 in formula (1), a substituent represented by formula (a) is preferred.

[0026] Specific preferred examples of the compound represented by the formula (1) include the following, but the present invention is not limited to these.

[0027] [ka]

[0028] [ka]

[0029] [ka]

[0030] [ka]

[0031] [ka]

[0032] [ka]

[0033] The compound represented by formula (1) can be synthesized by using a conventionally known method, for example, as described in WO87 / 02688.

[0034] The anthraquinone compound of the present invention represented by formula (1) has a high order parameter (S value). The order parameter (S value) in the present invention can be determined from the following formula described in "Liquid Crystal Device Handbook" (edited by Committee 142 of the Japan Society for the Promotion of Science, Nikkan Kogyo Shimbun, Ltd., 1989), based on spectroscopic measurement of the dichroic ratio of an anthraquinone compound (dichroic dye) represented by formula (1). S=(A / / -A ⊥ ) / (2A ⊥ +A / / ) During the ceremony, “A / / " and "A ⊥ " and " indicate the absorbance of the dye for light polarized parallel and perpendicular to the alignment direction of the liquid crystal. The calculated S value ranges from 0 to 1, and theoretically, the closer the value is to 1, the better the contrast will be when used as a GH (guest-host) type photochromic element.

[0035] 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 formula (1) and a liquid crystal material.

[0036] The content of the anthraquinone compound represented by formula (1) in the liquid crystal composition is not particularly limited, but is preferably 0.5 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the liquid crystal material. When a dichroic dye (described below) other than the compound represented by formula (1) is used in combination, the total content of the anthraquinone compound represented by formula (1) and the dichroic dye other than the compound represented by formula (1) is preferably within the above range (0.5 to 10 parts by mass per 100 parts by mass of the liquid crystal material).

[0037] The liquid crystal material 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 crystal properties such as nematic liquid crystal, cholesteric liquid crystal, smectic liquid crystal, etc., but among these, nematic liquid crystal is preferred. Examples of compounds 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, Ltd., 1989).

[0038] The liquid crystal composition of the present invention may contain a dichroic dye other than the anthraquinone compound represented by formula (1), or an optically active substance exhibiting a liquid crystal phase such as cholesteryl noenoate or an optically active substance not exhibiting a liquid crystal phase, various additives such as an ultraviolet absorber and an antioxidant, a photocurable compound, a photopolymerization initiator, etc.

[0039] The photocurable compound that may be contained in the liquid crystal composition of the present invention is not particularly limited as long as it is a compound having a functional group that can be polymerized by the action of a photopolymerization initiator described below when irradiated with light. Examples of the photocurable compound 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. In this specification, the term "(meth)acrylate" means "methacrylate and / or acrylate."

[0040] The (meth)acrylate compound contained in the liquid crystal composition of the present invention includes, for example, 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.

[0041] The mono(meth)acrylate compound is preferably a mono(meth)acrylate having a linear, cyclic or branched alkyl group having 5 to 13 carbon atoms. 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; cyclic alkyl mono(meth)acrylates such as isobornyl (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.

[0042] 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, as well as trialkylene glycol di(meth)acrylates such as triethylene glycol di(meth)acrylate.

[0043] The liquid crystal composition of the present invention may contain a mono(meth)acrylate compound and a di(meth)acrylate compound in combination. When a mono(meth)acrylate compound and a di(meth)acrylate compound are used in combination, the mass ratio of the mono(meth)acrylate compound to the di(meth)acrylate compound is preferably 10:90 to 96:4, and more preferably 50:50 to 95:5.

[0044] The photopolymerization initiator that may be contained in the composition of the present invention is not particularly limited as long as it is a compound that can polymerize a photocurable compound by irradiation with light. It is preferable that the photopolymerization initiator does not remain in the cured product after irradiation with light and cause deterioration of the dichroic dye such as the anthraquinone compound represented by formula (1). 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.

[0045] When the composition of the present invention contains a photocurable compound and a photopolymerization initiator, the blending ratio of the total of the anthraquinone compound represented by formula (1) and the liquid crystal material to the photocurable compound is preferably 90:10 to 50:50 by mass, more preferably 80:20 to 50:50, and even more preferably 65:35 to 50:50. By setting the blending ratio of the photocurable compound within this range, it is possible to prevent separation of the liquid crystal material and the photocurable compound before curing by light irradiation and to prevent a decrease in the light-shielding properties of the cured product. When a dichroic dye (described later) other than the compound represented by formula (1) is used in combination, the blending ratio of the total of all dichroic dyes including the anthraquinone compound represented by formula (1) and the liquid crystal material to the photocurable compound in the composition of the present invention is preferably within the above range (90:10 to 50:50 in mass ratio). The more preferred and even more preferred ranges are also the same as those above.

[0046] When the composition of the present invention contains a photocurable compound and a photopolymerization initiator, the content of the photopolymerization initiator is preferably 0.1 to 5 parts by mass per 100 parts by mass of the photocurable compound.

[0047] The composition of the present invention may contain a dichroic dye other than the anthraquinone compound represented by formula (1). 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, etc. 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.

[0048] When a dichroic dye other than the anthraquinone compound represented by formula (1) is used in combination, the content of the anthraquinone compound represented by formula (1) in the total dichroic dye is not particularly limited as long as it does not impair the effects of the present invention. The amount is preferably 1 to 80% by mass, more preferably 5 to 70% by mass, and even more preferably 10 to 50% by mass.

[0049] The composition of the present invention may further contain in combination a benzotriazole-based, benzophenone-based, hindered amine-based, or other light stabilizer, a phosphite-based, hindered phenol-based, or other antioxidant, 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, or 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.

[0050] The composition of the present invention is obtained by mixing and stirring the essential components, an anthraquinone compound represented by formula (1) and a liquid crystal material, as well as, optionally, a photocurable compound, a photopolymerization initiator, and any optional components. While mixing and stirring can be performed simply by placing all components in a container and stirring manually, it is more effective to use a device such as a magnetic stirrer. To efficiently prepare a homogeneous composition, it is preferable to first prepare a homogeneous mixture of the photocurable compound, photopolymerization initiator, and liquid crystal material, and then add the anthraquinone compound represented by formula (1) and any optional components and stir and mix them. Heating may be applied during stirring and mixing, if necessary. Stirring and mixing under a light source emitting the absorption wavelength of the photopolymerization initiator is preferably performed for as short a time as possible. After mixing the components, the mixture may be further filtered using a mesh, membrane filter, or the like.

[0051] By irradiating the composition of the present invention containing a photocurable compound and a photopolymerization initiator with light, a cured product of the liquid crystal composition is obtained in which the photocurable compound component is cured (polymerized). Note that the "cured product" in this invention means a state in which the functional group of the photocurable compound is polymerized or copolymerized by light irradiation, and does not necessarily mean a cured product in which the anthraquinone compound represented by formula (1), the liquid crystal material, etc., have contributed to the curing reaction. The light source for irradiating light is not particularly limited as long as it is capable of irradiating light of a wavelength absorbed by the photopolymerization initiator. Preferred light sources include high-pressure mercury lamps, metal halide lamps, xenon lamps, and halogen lamps capable of irradiating ultraviolet light.

[0052] 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 such as sputtering, over the entire surface or in part of the substrate, forming thin films of metal oxides, metals, semiconductors, or organic conductive materials, using known coating methods, printing, or vapor deposition 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 by vapor deposition such as sputtering or printing, from the standpoints of productivity and processability. It is more preferable that both of the pair of substrates are transparent substrates having transparent electrodes. Electrodes or wiring for connecting the electrodes to the outside may be provided on the substrates. For example, a segment drive electrode substrate, a matrix drive electrode substrate, or an active matrix drive electrode substrate may be used. 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, silicone, and cyanide compounds, inorganic compounds such as SiO2, TiO2, and ZrO2, or mixtures thereof.

[0053] The use of a plastic film as a substrate allows for a flexible and lightweight light-control device. Therefore, the light-control device 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-control device 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-control device 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-control device, or a color filter or polarizer filter may be laminated thereon. Furthermore, the light-control device may be laminated as an electroluminescence display device, a light-emitting diode display device, an electrochromic display device, or another liquid crystal display device.

[0054] The driving device for applying a voltage to the light-adjusting element of the present invention is a device capable of applying a DC voltage of 2 to 100 V or an AC voltage of 10 to 1000 Hz, and which opens or shorts the electrodes when no voltage is applied. The 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.

[0055] The anthraquinone compound represented by formula (1) of the present invention has a high order parameter, and a light-controlling device using a liquid crystal composition containing the compound can realize a high-contrast display and also has excellent light resistance and heat resistance under long-term outdoor exposure. Therefore, the light-controlling device is ideal for use in vehicles or building materials. [Example]

[0056] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. 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.

[0057] Example 1 (Synthesis of the anthraquinone compound of the present invention represented by formula (1)) (Step 1-1) Synthesis of an intermediate compound represented by the following formula (2) To 120 parts of DMF, 10.0 parts of 1,5-dichloroanthraquinone, 7.3 parts of potassium carbonate, and 6.0 parts of 4-hydroxybenzenethiol were added and stirred at 60°C for 4 hours. After the reaction solution was cooled to 25°C, 240 parts of methanol was added and stirred for 1 hour. The reaction product was collected by filtration and dried in a hot air dryer at 80°C for 24 hours to obtain 6.3 parts of an intermediate compound represented by the following formula (2).

[0058] [ka]

[0059] (Step 1-2) Synthesis of an intermediate compound represented by the following formula (3) To 70 parts of DMF, 6.3 parts of the intermediate compound represented by formula (2) obtained in step (1-1), 3.6 parts of potassium carbonate, and 5.7 parts of 4-octylbenzenethiol were added, and the mixture was stirred at 60°C for 2 hours. After the reaction solution was cooled to 25°C, 140 parts of methanol was added and the mixture was stirred for 1 hour. The reaction product was collected by filtration, washed with toluene, and then dried in a hot air dryer at 80°C for 24 hours to obtain 5.1 parts of the intermediate compound represented by formula (3):

[0060] [ka]

[0061] Step (1-3) Synthesis of Compound No. 7 To 50 parts of DMF, 5.1 parts of the intermediate compound represented by formula (3) obtained in step (1-2), 1.5 parts of potassium carbonate, and 2.2 parts of benzyl bromide were added and stirred at 100°C for 2 hours. The reaction solution was then cooled to 25°C, and 200 parts of methanol was added and stirred for 1 hour. The reaction product was collected by filtration, washed with methanol, and then dried in a hot air dryer at 80°C for 24 hours. The resulting crude product was dissolved in toluene and purified using a column chromatography column with toluene as the developing solvent. The solvent was removed from the purified solution by vacuum distillation, and the solution was dried in a hot air dryer at 80°C for 24 hours to obtain 4.0 parts of the compound represented by No. 7 of the above specific example as an orange solid. The maximum absorption wavelength of this compound in methanol was 449 nm.

[0062] Example 2 (Synthesis of the anthraquinone compound of the present invention represented by formula (1)) Step (2-1) Synthesis of Compound No. 10 The procedure of Example 1 was repeated, except that 5.7 parts of 4-octylbenzenethiol in step 1-2 was changed to 4.3 parts of 4-n-butylbenzenethiol, and 2.2 parts of benzyl bromide in step 1-3 was changed to 2.4 parts of 4-i-propylbenzyl chloride, to obtain 3.3 parts of the compound represented by the above specific example No. 10 as an orange solid. The maximum absorption wavelength of this compound in methanol was 450 nm.

[0063] Example 3 (Synthesis of the anthraquinone compound of the present invention represented by formula (1)) (Step 3-1) Synthesis of Compound Represented by Specific Example No. 15 Except for changing 5.7 parts of 4-octylbenzenethiol in step 1-2 to 4.3 parts of 4-t-butylbenzenethiol and changing 2.2 parts of benzyl bromide in step 1-3 to 2.4 parts of 4-t-butylbenzyl chloride, the procedure was repeated as in Example 1 to obtain 3.5 parts of the compound represented by the above specific example No. 15 as an orange solid. The maximum absorption wavelength of this compound in methanol was 450 nm.

[0064] Example 4 (Synthesis of the anthraquinone compound of the present invention represented by formula (1)) (Step 4-1) Synthesis of Compound Represented by Specific Example No. 17 The procedure of Example 1 was repeated, except that 2.2 parts of benzyl bromide in step 1-3 was replaced with 2.4 parts of 4-t-butylbenzyl chloride, to obtain 3.0 parts of the compound represented by the above specific example No. 17 as an orange solid. The maximum absorption wavelength of this compound in methanol was 449 nm.

[0065] Example 5 (Synthesis of the anthraquinone compound of the present invention represented by formula (1)) (Step 5-1) Synthesis of Compound Represented by Specific Example No. 48 Except for changing 5.7 parts of 4-octylbenzenethiol to 5.9 parts of 4-octyloxybenzenethiol in step 1-2 and changing 2.2 parts of benzyl bromide to 2.4 parts of 4-t-butylbenzyl chloride in step 1-3, the same procedure as in Example 1 was repeated to obtain 3.9 parts of the compound represented by the above specific example No. 48 as an orange solid. The maximum absorption wavelength of this compound in methanol was 452 nm.

[0066] Synthesis Example 1 (Synthesis of Comparative Compound) The compound represented by No. 2 in Table 2 of JP-A No. 63-72760 (compound represented by the following formula (X)) was obtained by a known synthesis method.

[0067] [ka]

[0068] Synthesis Example 2 (Synthesis of Comparative Compound) The compound represented by No. 1 in Table 2-1 of JP-A-62-101657 (compound represented by the following formula (Y)) was obtained by a known synthesis method.

[0069] [ka]

[0070] Synthesis Example 3 (Synthesis of Comparative Compound) The compound represented by Example 11 of EP59036A1 (compound represented by the following formula (Z)) was obtained by a known synthesis method.

[0071] [ka]

[0072] Example 6 (Preparation of Liquid Crystal Composition of the Present Invention) A liquid crystal composition of the present invention was prepared by mixing 0.003 parts of the compound represented by No. 7, a specific example obtained in Example 1, 0.306 parts of 1-cyano-4'-n-pentylbiphenyl, 0.15 parts of 1-cyano-4'-n-heptylbiphenyl, 0.096 parts of 1-cyano-4'-n-octyloxybiphenyl, and 0.048 parts of 1-cyano-4''-n-pentylterphenyl at room temperature.

[0073] Examples 7 to 10 and Comparative Examples 1 to 3 (Preparation of Liquid Crystal Compositions of the Present Invention and Comparative Examples) A liquid crystal composition of the present invention and a comparative liquid crystal composition were obtained in the same manner as in Example 6, except that the compound represented by Specific Example No. 7 obtained in Example 1 was changed to the compound represented by Specific Example No. 10 obtained in Example 2, the compound represented by Specific Example No. 15 obtained in Example 3, the compound represented by Specific Example No. 17 obtained in Example 4, the compound represented by Specific Example No. 48 obtained in Example 5, the compound represented by Formula (X) obtained in Synthesis Example 1, the compound represented by Formula (Y) obtained in Synthesis Example 2, or the compound represented by Formula (Z) obtained in Synthesis Example 3, respectively.

[0074] Example 11 (Fabrication of the light-adjusting element of the present invention) The liquid crystal composition obtained in Example 6 was sealed in a device having a transparent electrode and consisting of two glass substrates, one above the other, which had been subjected to a homogeneous alignment treatment by rubbing a polyamide resin on the surface in contact with the liquid crystal, with a gap of 15 μm between the substrates. In the device thus obtained, the liquid crystal was in a homogeneous alignment state when no voltage was applied, and the dye molecules (the anthraquinone compound obtained in Example 1) were also in a similar alignment state according to the liquid crystal.

[0075] Examples 12 to 15 and Comparative Examples 4 to 6 (Preparation of light-controlling elements of the present invention and comparative examples) The light control elements of the present invention and for comparison were prepared in accordance with Example 11, except that the liquid crystal composition obtained in Example 6 was changed to that of Examples 7 to 10 and Comparative Examples 1 to 3, respectively.

[0076] (Calculation of order parameters for photochromic elements) The maximum absorption wavelength and order parameter were measured for the light-controlling elements obtained in Examples 11 to 15 and Comparative Examples 4 to 6. Linearly polarized light parallel to the alignment direction and linearly polarized light perpendicular to the alignment direction were incident on the prepared light-controlling elements. From the spectra obtained at that time, the absorbance (A / / ), and absorbance for polarized light perpendicular to the orientation direction (A ⊥ The order parameter (S value) at the maximum absorption wavelength where the degree of polarization ρ was maximum was calculated using the following formula. The results are shown in Table 1. S=(A / / -A ⊥ ) / (2A ⊥ +A / / )

[0077] [Table 1]

[0078] As shown in Table 1, the light control devices of Examples 11 to 15 have higher order parameters than the light control devices of Comparative Examples 4 to 6, and are clearly superior as light control devices.

[0079] Example 16 (Preparation of Liquid Crystal Composition of the Present Invention) 0.01 parts of the compound represented by No. 10 of the specific example obtained in Example 2, 0.380 parts of isobornyl acrylate (manufactured by Osaka Organic Chemical Industry, monoacrylate), 0.020 parts of triethylene glycol dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.), 0.306 parts of 1-cyano-4'-n-pentylbiphenyl, 0.15 parts of 1-cyano-4'-n-heptylbiphenyl, 0.096 parts of 1-cyano-4'-n-octyloxybiphenyl, 0.048 parts of 1-cyano-4"-n-pentylterphenyl, 0.004 parts of Irgacure TPO (manufactured by BASF), 0.004 parts of Irgacure 184 (manufactured by BASF), and 0.010 parts of a spacer agent having a diameter of 20 μm (manufactured by Sekisui Chemical Co., Ltd., "Micropearl (registered trademark) SP220") were mixed at room temperature and stirred at 50°C for 2 hours. Next, the mixed liquid was cooled to room temperature and passed through a 1 μm membrane filter to prepare a liquid crystal composition of the present invention.

[0080] Examples 17 and 18 and Comparative Example 7 (Preparation of Liquid Crystal Compositions of the Present Invention and Comparative Examples) A liquid crystal composition of the present invention and a comparative liquid crystal composition were obtained in the same manner as in Example 16, except that the compound represented by Specific Example No. 10 obtained in Example 2 was changed to the compound represented by Specific Example No. 15 obtained in Example 3, the compound represented by Specific Example No. 17 obtained in Example 4, and the compound represented by Formula (X) obtained in Synthesis example 1, respectively.

[0081] Examples 19 to 21 and Comparative Example 8 (Preparation of light-controlling elements of the present invention and comparative examples) The liquid crystal compositions obtained in Examples 16 to 18 and Comparative Example 7 were each applied using an applicator onto the ITO film of a 5 cm square PET film provided with an ITO film, to form a liquid crystal composition layer. Next, this film and a 5 cm square PET film provided with the same ITO film as above were superimposed so that the liquid crystal composition layer on the ITO film faced the ITO film. Thereafter, the thus obtained laminate sample of the two films and the liquid crystal composition layer was heated at 23°C on a thermoplate, and the light intensity of 365 nm from an LED lamp was 9 mW / cm. 2 The photo-curable compound was photo-cured by irradiating it with light for 1 minute, thereby obtaining a light control element of the present invention and a light control element for comparison.

[0082] (Calculation of transmittance difference of dimming element) For the light-control devices obtained in Examples 19 to 21 and Comparative Example 8, the maximum absorption wavelength was measured by the above-mentioned method, and the transmittance difference (change in transmittance) was calculated from the measurement results of the transmittance (%) at the maximum absorption wavelength when an AC voltage of 100 V (50 Hz sine wave) was applied and when no AC voltage was applied.

[0083] [Table 2]

[0084] As shown in Table 2, it is clear that the light control devices of Examples 19 to 21 have a larger difference in transmittance between when a voltage is applied and when no voltage is applied than the light control device of Comparative Example 8.

[0085] Example 22 (Preparation of black photochromic element) A black photochromic element was produced in the same manner as in Examples 19 to 21 using a liquid crystal composition of the present invention prepared in the same manner as in Example 16, except that 0.012 parts of LCD121 (anthraquinone compound, manufactured by Nippon Kayaku Co., Ltd.) and 0.009 parts of LCD212 (anthraquinone compound, manufactured by Nippon Kayaku Co., Ltd.) were added. The average transmittance difference of the obtained black photochromic element in the range of 400 to 700 nm was 32%, and the element exhibited high contrast.

[0086] The black dimming element obtained in Example 22 showed no change in transmittance even after 500 hours in a xenon light resistance test, and also had excellent light resistance when exposed to light for a long period of time. Furthermore, even when a 100V AC (50Hz sine wave) voltage was applied under conditions of 110°C, there was no change in transmittance, and the element also had excellent heat resistance when energized. These results demonstrate that the black dimming element of Example 22 is a black liquid crystal dimming element with high contrast, excellent light resistance, and excellent heat resistance when energized. Industrial Applicability

[0087] By using the liquid crystal composition containing the anthraquinone compound of the present invention, a light-controlling device having excellent contrast, light fastness, and heat resistance under application of current can be obtained. The light-controlling device having these excellent properties is suitable for use in vehicles or as a building material.

Claims

1. The following formula (1) 【Chemical 1】 (In the formula, R １ represents a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, or a linear or branched alkoxy group having 1 to 12 carbon atoms. ２ is represented by the following formula (a): 【Chemistry 2】 (In formula (a), R ３ is a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, a linear or branched alkoxy group having 1 to 8 carbon atoms, or —CH ２ OR ４ R represents a substituent represented by ４ represents a linear or branched alkyl group having 1 to 8 carbon atoms. Or the following formula (b): 【Chemistry 3】 (In formula (b), R ５ is a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or —CH ２ OR ６ R represents a substituent represented by ６ represents a linear or branched alkyl group having 1 to 8 carbon atoms. represents a substituent represented by the following formula: An anthraquinone compound represented by the formula:

2. R in formula (1) ２ is a substituent represented by formula (a), and R in formula (a) ３ 2. The anthraquinone compound according to claim 1, wherein is a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkoxy group having 1 to 8 carbon atoms.

3. R in formula (a) ３ The anthraquinone compound according to claim 2, wherein is a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms.

4. R in formula (1) ２ is a substituent represented by formula (b), and R in formula (b) ５ 2. The anthraquinone compound according to claim 1, wherein is a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms.

5. R in formula (1) １ The anthraquinone compound according to claim 1 , wherein is a linear or branched alkoxy group having 1 to 8 carbon atoms.

6. R in formula (1) １ The anthraquinone compound according to claim 5, wherein is a linear alkoxy group having 4 to 8 carbon atoms.

7. R in formula (1) １ The anthraquinone compound according to claim 1 , wherein is a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms.

8. R in formula (1) １ 8. The anthraquinone compound according to claim 7, wherein is a linear alkyl group having 4 to 8 carbon atoms.

9. A liquid crystal composition comprising an anthraquinone compound according to claim 1 and a liquid crystal material.

10. The liquid crystal composition according to claim 9 , further comprising a photocurable compound and a photopolymerization initiator.

11. A liquid crystal composition containing an anthraquinone compound according to any one of claims 1 to 4, a liquid crystal material, and at least one dye compound other than the anthraquinone compound according to claim 1.

12. A liquid crystal composition containing an anthraquinone compound described in any one of claims 1 to 4, a liquid crystal material, at least one dye compound other than the anthraquinone compound described in claim 1, and a photocurable compound and a photopolymerization initiator.

13. A photocured product of the liquid crystal composition described in claim 10.

14. A photocured product of the liquid crystal composition described in claim 12.

15. 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 9 sandwiched between the pair of substrates.

16. A dimming element comprising a pair of opposing substrates, at least one of which is a transparent substrate having a transparent electrode, and a photocured material according to claim 13 sandwiched between the pair of substrates.

17. The light-adjusting element according to claim 15 , wherein both of the pair of substrates are transparent substrates having transparent electrodes.

18. A dimming element as described in claim 16, wherein both of the pair of substrates are transparent substrates having transparent electrodes.

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