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

Abstract

The purpose of the present invention is to provide a novel anthraquinone compound, and to provide: a dichroic dye constituted of the novel anthraquinone compound; a liquid crystal composition which contains the dichroic dye; and preferably a dimming element having excellent contrast and light resistance and containing said composition.　The present invention discloses an anthraquinone compound represented by formula A below (wherein R1 represents a C3-16 branched alkyl group, and R2 represents a hydrogen atom, a C1-8 straight-chain or branched alkyl group, or a C1-8 straight-chain or branched alkoxy group). In addition, the present invention discloses a liquid crystal composition including the anthraquinone compound and a liquid crystal material, and a dimming element containing said composition.

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 (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 the 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 (Patent Documents 3 and 4). When such light-controlling panels are used in automobile windows, they are required to have not only clear visibility when transparent and without fogging, but also a deep color when light is blocked, and light resistance that does not decrease in transmittance even when exposed to light for long periods at high temperatures due to long-term exposure during outdoor use.

[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 (Patent Document 5, Patent Document 6).

[0004] Such dichroic dyes are required to have not only contrast when used in a display device, but also light resistance and heat resistance. Although efforts have been made to improve these properties, none have been found that satisfy the contrast and light resistance. For example, Patent Documents 5 and 6 disclose dichroic dyes suitable for light-adjusting applications, but the dyes in these documents have insufficient contrast and light resistance. [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. 61-87756 [Patent Document 6] 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 this novel anthraquinone compound, a liquid crystal composition containing the dichroic dye, and a light-controlling device which contains the composition and has excellent contrast and light resistance. [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 a light-controlling element having excellent contrast and light resistance can be obtained by producing the light-controlling element using a liquid crystal composition containing a dichroic dye that is such a novel anthraquinone compound. That is, the various aspects included in the present invention are as follows. [1]. The following formula (A) [ka] (In the formula, R1 represents a branched alkyl group having 3 to 16 carbon atoms, and R2 represents 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.) An anthraquinone compound represented by the formula: [2]. The anthraquinone compound according to the above item [1], wherein R1 is a branched alkyl group having 6 to 16 carbon atoms. [3]. R1 is the following formula (B) [ka]

[0008] (In the formula, R3 represents a linear alkyl group having 1 to 6 carbon atoms, and R4 represents a linear alkyl group having 1 to 9 carbon atoms. However, the total number of carbon atoms in the linear alkyl group represented by R3 and the linear alkyl group represented by R4 is 5 to 15.) The anthraquinone compound according to the above item [2], wherein the branched chain alkyl group is represented by the following formula: [4]. The anthraquinone compound according to the above item [3], wherein R3 is a methyl group and R4 is a linear alkyl group having 4 to 7 carbon atoms, or R3 is an ethyl group or a propyl group and R4 is a linear alkyl group having 3 to 7 carbon atoms. [5]. The anthraquinone compound according to any one of the above items [1] to [4], wherein R2 is a linear alkoxy group having 1 to 8 carbon atoms. [6]. The anthraquinone compound according to the above item [5], wherein R2 is a linear alkoxy group having 1 to 4 carbon atoms. [7].

[0023] The anthraquinone compound according to any one of [1] to [4] above, wherein R2 is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. [8]. A liquid crystal composition comprising the anthraquinone compound according to any one of the above items [1] to [7] and a liquid crystal material. [9]. The liquid crystal composition according to item [8], further comprising a dichroic dye other than the anthraquinone compound represented by formula (A).

[10] . The liquid crystal composition according to item [8] or [9], further comprising a photocurable compound and a photopolymerization initiator.

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

[10] .

[12] . 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 the above item [8] or [9] or a cured product according to the above item

[11] sandwiched between the pair of opposing substrates.

[13] . The light-controlling element according to the above item

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

[0009] The anthraquinone compounds of the present invention are useful as dichroic dyes for liquid crystal light-controlling devices. By using a liquid crystal composition containing these dichroic dyes, a light-controlling device having excellent contrast and light resistance can be obtained. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below. The compound of the present invention (anthraquinone compound) is represented by the following formula (A).

[0011] [ka]

[0012] In formula (A), R1 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 R1 in formula (A) 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 1-methylpentyl group, a 2-methylpentyl group, a 1-methylhexyl group, a 2-methylhexyl group, a 1-methylheptyl group, a 2-methylheptyl group, a 1-methyloctyl group, a 2-methyloctyl group, a 1-methylnonyl 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 1-ethylpropyl group, a 2-ethylpropyl group, and a 1-ethylbutyl group. , 2-ethylbutyl group, 1-ethylhexyl group, 2-ethylhexyl group, 1-ethylheptyl group, 2-ethylheptyl group, 1-propylhexyl group, 2-propylhexyl group, 1-butylhexyl group, 2-butylhexyl group, 1-pentylhexyl group, 2-pentylhexyl group, 1-pentylheptyl group, 2-pentylheptyl group, 1-pentyloctyl group, 2-pentyloctyl group, 1-pentylnonyl group, 2-pentylnonyl group, 1-pentyldecyl group, 2-pentyldecyl group, 1-hexylheptyl group, 2-hexylheptyl group, 1-hexylnonyl group, 2-hexylnonyl group, 1-hexyldecyl group, and 2-hexyldecyl group. R1 is preferably a branched alkyl group having 6 to 16 carbon atoms.

[0013] As R1 in formula (A), a branched alkyl group represented by the following formula (B) is more preferred. [ka]

[0014] In formula (B), R3 represents a linear alkyl group having 1 to 6 carbon atoms. Specific examples of the linear alkyl group having 1 to 6 carbon atoms represented by R3 in formula (B) include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, and an n-hexyl group. R3 is preferably a methyl group, an ethyl group, or an n-propyl group, and more preferably an ethyl group or an n-propyl group.

[0015] In formula (B), R4 represents a linear alkyl group having 1 to 9 carbon atoms. Specific examples of the linear alkyl group having 1 to 9 carbon atoms represented by R4 include the same as the specific examples of the linear alkyl group having 1 to 6 carbon atoms represented by R3, as well as an n-heptyl group, an n-octyl group, and an n-nonyl group. R4 is preferably an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, or an n-heptyl group.

[0016] However, the total number of carbon atoms in the linear alkyl group represented by R3 and the linear alkyl group represented by R4 is 5 to 15. In other words, the branched alkyl group represented by formula (B) has 6 to 16 carbon atoms.

[0017] In formula (B), it is preferable that R3 is a methyl group and R4 is a linear alkyl group having 4 to 7 carbon atoms, or that R3 is an ethyl group or a propyl group and R4 is a linear alkyl group having 3 to 7 carbon atoms. It is more preferable that R3 is an ethyl group or a propyl group and R4 is a linear alkyl group having 3 to 7 carbon atoms.

[0018] In formula (A), R2 represents 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. Specific examples of the linear or branched alkyl group having 1 to 8 carbon atoms represented by R2 in formula (A) include the same branched alkyl groups having 3 to 8 carbon atoms as those described in the section on specific examples of the branched alkyl group having 3 to 16 carbon atoms as represented by R1 in formula (A) and the same linear alkyl groups having 1 to 8 carbon atoms as those described in the section on specific examples of the linear alkyl group having 1 to 9 carbon atoms as represented by R4 in formula (B). A linear or branched alkyl group having 1 to 4 carbon atoms is preferred.

[0019] Specific examples of the linear or branched alkoxy group having 1 to 8 carbon atoms represented by R2 in formula (A) 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, and an octyloxy group, etc. A linear alkoxy group having 1 to 8 carbon atoms is preferred, and a linear alkoxy group having 1 to 4 carbon atoms is more preferred.

[0020] In formula (A), R2 is preferably a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear alkoxy group having 1 to 8 carbon atoms. R2 is more preferably a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or a linear alkoxy group having 1 to 4 carbon atoms.

[0021] Specific examples of suitable compounds represented by the formula (A) include the following.

[0022] [ka]

[0023] [ka]

[0024] [ka]

[0025] [ka]

[0026] [ka]

[0027] [ka]

[0028] The compound represented by the above formula (A) can be synthesized by utilizing a conventionally known method, for example, as described in WO87 / 02688.

[0029] The liquid crystal composition of the present invention (hereinafter sometimes simply referred to as "the composition of the present invention") contains an anthraquinone compound represented by the above formula (A) and a liquid crystal material.

[0030] The order parameter (S value) of the anthraquinone compound represented by the above formula (A) contained in the composition of the present invention is preferably 0.76 or more, more preferably 0.77 or more. The order parameter (S value) in the present invention can be calculated from the following formula described in "Liquid Crystal Device Handbook" (edited by the 142nd Committee 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 (A). 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. Theoretically, the calculated S value ranges from 0 to 1, and the closer the value is to 1, the better the contrast of the guest-host photochromic element.

[0031] The content of the anthraquinone compound represented by formula (A) in the liquid crystal composition is not particularly limited, but is preferably 0.5 to 5 parts by mass relative to 100 parts by mass of the liquid crystal material. When a dichroic dye (described later) other than the compound represented by formula (A) is used in combination, the total content of the anthraquinone compound represented by formula (A) and the dichroic dye other than the compound represented by formula (A) is preferably within the above range, i.e., 0.5 to 5% by mass relative to 100 parts by mass of the liquid crystal material.

[0032] The liquid crystal material contained in the 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., but among these, nematic liquid crystal is preferred. Examples of compounds having liquid crystallinity include the liquid crystal compounds described in pages 154 to 192 and 715 to 722 of the aforementioned "Liquid Crystal Device Handbook" (edited by the 142nd Committee of the Japan Society for the Promotion of Science, Nikkan Kogyo Shimbun, Ltd., 1989).

[0033] 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 compound represented by the above formula (A) or cholesteryl noenoate, various additives such as an ultraviolet absorber and an antioxidant, a photocurable compound, a photopolymerization initiator, etc.

[0034] The photocurable compound that may be contained in the 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. As the photocurable compound, it is preferable to use both a monofunctional monomer having one polymerizable functional group and a bifunctional monomer having two polymerizable functional groups in combination.

[0035] The monofunctional monomer used as the photocurable compound in the composition of the present invention is compatible with the liquid crystal in the composition before light irradiation, and when polymerized by light irradiation, it phase-separates from the liquid crystal to form a cured phase, thereby playing a role in mitigating the interfacial interaction with the liquid crystal phase. Therefore, if the polarity of the monofunctional monomer is excessively high, the interfacial interaction with the liquid crystal phase becomes too strong, inhibiting the movement of the liquid crystal and requiring a high driving voltage. Therefore, it is preferable that the polarity of the monofunctional monomer is low.

[0036] The bifunctional monomer used as the photocurable compound in the composition of the present invention phase-separates from the liquid crystal to form a cured phase when polymerized by light irradiation, and serves to stabilize the separation state with the liquid crystal phase. Therefore, if the polarity of the bifunctional monomer is excessively high, the interfacial interaction with the liquid crystal phase becomes too strong, inhibiting the movement of the liquid crystal and requiring a high driving voltage. Therefore, it is preferable that the polarity of the bifunctional monomer is also low.

[0037] Examples of photocurable compounds 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. That is, it is more preferable to use 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".

[0038] 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.

[0039] 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, as well as trialkylene glycol di(meth)acrylates such as triethylene glycol di(meth)acrylate.

[0040] When a monofunctional monomer and a bifunctional monomer are used in combination, the mass ratio of monofunctional monomer to bifunctional monomer is preferably 10:90 to 96:4, and more preferably 50:50 to 95:5. By using the monofunctional monomer in an amount within the above ratio range, the compatibility with the liquid crystal does not become too high, so that separation between the polymer (polymer phase) formed by light irradiation and the liquid crystal phase occurs to an appropriate extent, preventing gelation of the monomer alone, and facilitating the formation of a separated phase between the polymer phase and the liquid crystal phase.

[0041] The compatibility of the photocurable compound contained in the liquid crystal composition of the present invention with a liquid crystal material can be evaluated by visually observing the phase separation that occurs with a temperature drop after the photocurable compound and the liquid crystal material are dissolved in each other using a polarizing microscope, or by measuring the phase separation temperature obtained by DSC or other measurements. The phase separation temperature between the photocurable compound and the liquid crystal material is preferably in the range of 0 to 50°C, more preferably in the range of 10 to 40°C. By setting the phase separation temperature within this range, the compatibility between the photocurable compound and the liquid crystal material in the liquid crystal composition is good, and phase separation does not occur after polymerization of the photocurable compound proceeds by light irradiation. This prevents the resulting liquid crystal phase from becoming too small, allowing for a lower driving voltage and making it easier to maintain the compatibility of the composition until light irradiation.

[0042] 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 (A). 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.

[0043] When the composition of the present invention contains a photocurable compound and a photopolymerization initiator, the blending ratio of the total of the compound represented by Formula (A) 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 the above range, it is possible to prevent separation of the liquid crystal material and the photocurable compound before curing by light irradiation and a decrease in the light-blocking properties of the cured product. When a dichroic dye (described later) other than the compound represented by formula (A) is used in combination, the blending ratio of the total of all dichroic dyes including the compound represented by formula (A) 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 by mass ratio). The more preferred and even more preferred ranges are the same as those above.

[0044] 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.

[0045] By using a dichroic dye other than the compound represented by the above formula (A) in the composition of the present invention in combination, the contrast of the light-controlling element when light is blocked can be improved. 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.

[0046] When a dichroic dye other than the compound represented by formula (A) is used in combination, the content of the compound represented by formula (A) in the total dichroic dyes is not particularly limited as long as it does not impair the effects of the present invention, and the amount is preferably 1 to 95% by mass, more preferably 10 to 90% by mass, and even more preferably 30 to 80% by mass.

[0047] 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.

[0048] The composition of the present invention can be obtained by mixing and stirring the essential components, an anthraquinone compound represented by formula (A) and a liquid crystal material, as well as optional components such as a photocurable compound and a photopolymerization initiator, if necessary. Mixing and stirring can be performed simply by placing all components in a container and stirring manually, but stirring using a device such as a magnetic stirrer is more effective. 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 compound represented by formula (A) and other optional components and stir and mix. 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.

[0049] 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 the present 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 (A), 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. The temperature during light irradiation is preferably a temperature at which the composition can maintain a uniformly dissolved state, i.e., a temperature higher than the phase separation temperature, and more preferably a temperature in the range of 1 to 5°C higher than the phase separation temperature. When the temperature during light irradiation is higher than the phase separation temperature, separation of the photocurable compound and the liquid crystal material before light irradiation is prevented, and a more uniform cured product can be obtained. On the other hand, when the temperature during light irradiation is not significantly higher than the phase separation temperature, the domain size formed by the liquid crystal material can be prevented from becoming excessively small when the polymer of the photocurable compound obtained by photocuring separates from the liquid crystal material.

[0050] 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 them, and a layer of the liquid crystal composition of the present invention or a photocured product of the liquid crystal composition. 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, for example, forming a thin film of a metal oxide, metal, semiconductor, or organic conductive material over the entire surface or in part of the substrate using a known coating method, printing method, or vapor deposition method 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 a vapor deposition method such as sputtering or a printing method, 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.

[0051] 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.

[0052] The driving device for applying a voltage to the dimming element of the present invention is a device that can apply a DC voltage of 2 to 100 V or an AC voltage of 10 to 1000 Hz, and that opens or shorts the electrodes when no voltage is applied. Furthermore, this driving device may 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.

[0053] The photochromic element of the present invention may be either a black photochromic element or a color photochromic element depending on the application. The photochromic element of the present invention has an average transmittance of preferably 35% or more, more preferably 40% or more, when transmitting light in a specific wavelength range. Furthermore, the average transmittance of the photochromic element when blocking light is preferably 25% or less, more preferably 15% or less.

[0054] The black photochromic element has a neutral color, and in the visible light region, when no voltage is applied, it has little color leakage, excellent contrast, and excellent light resistance against long-term outdoor exposure, making it ideal for use in automobiles or building materials. [Example]

[0055] The present invention will be described in more detail below with reference to examples, but these are 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.

[0056] Example 1 (Synthesis of a specific example of a compound represented by formula (5)) (Step 1) Synthesis of intermediate compound represented by formula (47) To 120 parts of DMF were added 10.0 parts of 1,5-dichloroanthraquinone, 7.3 parts of potassium carbonate, and 6.0 parts of 4-hydroxybenzenethiol, and the mixture was stirred at 60°C for 4 hours. After the reaction solution was cooled to 25°C, 240 parts of methanol was added and the mixture was 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 (47).

[0057] [ka]

[0058] (Step 2) Synthesis of intermediate compound represented by formula (48) To 70 parts of DMF, 6.3 parts of the intermediate compound represented by formula (47) obtained in step 1, 3.6 parts of potassium carbonate, and 4.3 parts of 4-t-butylbenzenethiol 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 (48) below.

[0059] [ka]

[0060] (Step 3) Synthesis of the compound of the present invention represented by formula (5) 5.1 parts of the intermediate compound represented by formula (48) obtained in step 2, 1.6 parts of 2-methylhexanoyl chloride, and 1.8 parts of triethylamine were added to 70 parts of toluene and stirred at 25°C for 1 hour. Then, 40 parts of water was added to separate the organic phase. The aqueous layer was extracted with 60 parts of ethyl acetate, and the separated organic layer and the ethyl acetate extract were mixed and washed with 70 parts of saturated brine. The washed organic layer was dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The resulting crude product was dissolved in toluene and purified using a column chromatography column with toluene as the developing solvent. The solvent was evaporated under reduced pressure from the purified solution, and the solution was dried in a hot air oven at 80°C for 24 hours to obtain 3.5 parts of the compound represented by formula (5) as an orange solid. The maximum absorption wavelength of this compound in toluene solution was 448 nm.

[0061] Example 2 (Synthesis of a specific example of a compound represented by formula (7)) 3.8 parts of the compound represented by the above formula (7) were obtained as an orange solid in the same manner as in Example 1, except that 1.6 parts of 2-methylhexanoyl chloride was changed to 2.2 parts of 2-ethylhexanoyl chloride in step 3. The maximum absorption wavelength of a toluene solution of this compound was 448 nm.

[0062] Example 3 (Synthesis of a specific example of a compound represented by formula (12)) 2.8 parts of the compound represented by the above formula (12) were obtained as an orange solid in the same manner as in Example 1, except that 4.3 parts of 4-t-butylbenzenethiol was replaced with 3.2 parts of 4-methylbenzenethiol in step 2, and 1.6 parts of 2-methylhexanoyl chloride was replaced with 2.2 parts of 2-ethylhexanoyl chloride in step 3. The maximum absorption wavelength of a toluene solution of this compound was 449 nm.

[0063] Example 4 (Synthesis of a specific example of a compound represented by formula (21)) 3.1 parts of the compound represented by the above formula (21) were obtained in the same manner as in Example 1, except that 4.3 parts of 4-t-butylbenzenethiol was replaced with 5.8 parts of n-octanethiol in step 2, and 1.6 parts of 2-methylhexanoyl chloride was replaced with 1.6 parts of 5-methylhexanoyl chloride in step 3. The maximum absorption wavelength of a toluene solution of this compound was 448 nm.

[0064] Example 5 (Synthesis of a specific example of a compound represented by formula (28)) 2.7 parts of the compound represented by the above formula (28) were obtained in the same manner as in Example 1, except that 4.3 parts of 4-t-butylbenzenethiol was replaced with 4.2 parts of n-butoxybenzenethiol in step 2, and 1.6 parts of 2-ethylheptanoyl chloride was used instead of 1.6 parts of 2-methylhexanoyl chloride in step 3. The maximum absorption wavelength of a toluene solution of this compound was 453 nm.

[0065] Synthesis Example 1 (Synthesis of Comparative Compound) The compound represented by No. 8 in Table 1 of JP-A No. 61-87756 (compound represented by the following formula (X)) was obtained by a known synthesis method.

[0066] [ka]

[0067] Synthesis Example 2 (Synthesis of Comparative Compound) The compound represented by Example 11 of EP59036A1 (compound represented by the following formula (Y)) was obtained by a known synthesis method.

[0068] [ka]

[0069] Example 6 (Preparation of a composition of the present invention) A liquid crystal composition of the present invention was prepared by mixing 0.0078 parts of the compound represented by formula (5) 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.

[0070] Examples 7 to 10 and Comparative Examples 1 and 2 (Preparation of Liquid Crystal Compositions of the Present Invention and Comparative Examples) The liquid crystal compositions of the present invention and comparative liquid crystal compositions were prepared in accordance with Example 6, except that the compound represented by formula (5) obtained in Example 1 was changed to the compound represented by formula (7) obtained in Example 2, the compound represented by formula (12) obtained in Example 3, the compound represented by formula (21) obtained in Example 4, the compound represented by formula (28) obtained in Example 5, the compound represented by formula (X) obtained in Synthesis example 1, and the compound represented by formula (Y) obtained in Synthesis example 2, respectively.

[0071] Examples 11 to 15 and Comparative Examples 3 and 4 (Preparation of light-controlling elements of the present invention and comparative examples) The liquid crystal compositions obtained in Examples 6 to 10 and Comparative Examples 1 and 2 were sealed in devices with a gap of 15 μm between the substrates, each of which had transparent electrodes and was made of two glass substrates, one above the other, that had been subjected to homogeneous alignment treatment by rubbing a polyamide resin on the surface that came into contact with the liquid crystal. In the device, when no voltage was applied, the liquid crystal was in a homogeneous alignment state, and the dye molecules were also in a similar alignment state according to the liquid crystal.

[0072] (Calculation of order parameters for photochromic elements) Linearly polarized light parallel to the alignment direction and linearly polarized light perpendicular to the alignment direction were incident on the light-controlling elements obtained in Examples 11 to 15 and Comparative Examples 3 and 4. From the spectra obtained at that time, the absorbance (A / / ) and absorbance (A ⊥ The order parameter (S value) at the maximum absorption wavelength (λmax) was calculated using the following formula. The results are shown in Table 1. S=(A / / -A ⊥ ) / (2A ⊥ +A / / )

[0073] [Table 1]

[0074] 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 3 and 4, and are clearly superior as light control devices.

[0075] (Light resistance test of dimming element) A UV cut filter with a wavelength of 400 nm or less was attached to the light control elements obtained in Examples 11 to 15 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 S values ​​were measured after 200 hours of light irradiation using a metal halide lamp. Table 2 below shows the S values ​​before light irradiation (the values ​​shown in Table 1 above) for each example of the light control element, as well as the S values ​​after 200 hours of light irradiation. As shown in Table 2, the S values ​​of the light control elements of Examples 11 to 15 changed little over time, but the S value of the light control element of Comparative Example 3 decreased significantly after 200 hours. These results confirmed that the light control elements of Examples 11 to 15 have excellent light resistance.

[0076] [Table 2]

[0077] Example 16 (Preparation of Liquid Crystal Composition of the Present Invention) A liquid crystal composition of the present invention was prepared by mixing 0.026 parts of the compound represented by the above formula (5) obtained in Example 1, 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 (Micropearl (registered trademark) SP220, manufactured by Sekisui Chemical Co., Ltd.) at room temperature.

[0078] Examples 17 to 20 and Comparative Example 5 (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 0.026 parts of the compound represented by formula (5) obtained in Example 1 were changed to 0.026 parts of the compound represented by formula (7) obtained in Example 2, 0.026 parts of the compound represented by formula (12) obtained in Example 3, 0.026 parts of the compound represented by formula (21) obtained in Example 4, 0.026 parts of the compound represented by formula (28) obtained in Example 5, and 0.007 parts of the compound represented by formula (X) obtained in Synthesis Example 1. The maximum solubility of the compound represented by formula (X) obtained in Synthesis Example 1 in the liquid crystal mixture was 0.007 parts.

[0079] Examples 21 to 25 and Comparative Example 6 (Preparation of light-controlling elements of the present invention and comparative examples) The liquid crystal compositions obtained in Examples 16 to 20 and Comparative Example 5 were applied to the ITO film of a 5 cm square PET film using an applicator to form a liquid crystal composition layer. Next, this film and a 5 cm square PET film having 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 to 2000 K with a temperature of 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.

[0080] (Calculating the contrast of the dimming element) The maximum absorption wavelength was measured for the light-control devices obtained in Examples 21 to 25 and Comparative Example 6, and the contrast (transmittance with applied voltage / transmittance with no applied voltage) was calculated from the transmittance measured at the maximum absorption wavelength with and without the application of 100 V AC voltage (50 Hz sine wave). The results are shown in Table 3.

[0081] [Table 3]

[0082] As shown in Table 3, the photochromic elements of Examples 21 to 25 had contrasts that were approximately twice or more that of the photochromic element of Comparative Example 6. Furthermore, the photochromic elements of Examples 21 to 25 had excellent light-blocking performance, with transmittances during light blocking that were 20% or more lower than those of the photochromic element of Comparative Example 6. Therefore, it is clearly understood that the photochromic elements of Examples 21 to 25 exhibited significantly superior performance compared to the photochromic element of Comparative Example 6.

[0083] (Light resistance test of dimming element) A UV cut filter with a wavelength of 400 nm or less was attached to the light control elements obtained in Examples 21 to 25 and Comparative Example 6, and the light control elements were then subjected to irradiation at an illuminance of 650 W / m at 63°C. 2 The absorbance at the maximum absorption wavelength after 24 hours of irradiation with a metal halide lamp was measured, and the absorbance retention ((δA)%) was calculated. The absorbance retention ((δA)%) is defined by the following formula, where A(0) is the absorbance value before irradiation (i.e., 0 hours after irradiation) and A(24) is the absorbance value after 24 hours of irradiation. A larger δA value indicates better light resistance. (δA)% = (A(24) / A(0)) × 100 The maximum absorption wavelength and absorbance retention rate for each photochromic element are shown in Table 4 below. As shown in Table 4, the photochromic elements of Examples 21 to 25 had significantly higher absorbance retention rates than the photochromic element of Comparative Example 6. Therefore, it is clearly understood that the photochromic elements of Examples 21 to 25 exhibited significantly superior light resistance compared to the photochromic element of Comparative Example 6.

[0084] [Table 4]

[0085] Example 26 (Preparation of black photochromic element) A liquid crystal composition of the present invention was prepared in the same manner as in Example 16, except that 0.026 parts of the compound represented by formula (5) obtained in Example 1 was changed to 0.009 parts of the compound represented by formula (7) obtained in Example 2, and 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. Using this liquid crystal composition, a black photochromic element was produced in the same manner as in Examples 21 to 25. The average contrast of the obtained black photochromic element at 400 to 700 nm was 3.5, demonstrating high contrast.

[0086] The black light-adjusting element obtained in Example 26 showed no change in transmittance even after 500 hours in a xenon light resistance test, and also showed excellent light resistance when exposed to light for a long period of time. This result demonstrated that the black light-adjusting element of Example 26 is a black liquid crystal light-adjusting element with high contrast and light resistance. Industrial Applicability

[0087] By using the liquid crystal composition of the present invention, a light-control liquid crystal element having high contrast and high light resistance can be obtained, and the element can be suitably used for outdoor building materials and in-vehicle applications that require high durability.

Claims

1. The following formula (A) 【Chemistry 1】 (In the formula, R １ represents a branched alkyl group having 3 to 16 carbon atoms; R ２ represents 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. An anthraquinone compound represented by the formula:

2. R １ 2. The anthraquinone compound according to claim 1, wherein is a branched alkyl group having 6 to 16 carbon atoms.

3. R １ is represented by the following formula (B): 【Chemistry 2】 (In the formula, R ３ represents a linear alkyl group having 1 to 6 carbon atoms; R ４ represents a linear alkyl group having 1 to 9 carbon atoms. ３ The number of carbon atoms in the linear alkyl group represented by R ４ The total number of carbon atoms in the linear alkyl group represented by is 5 to 15. The anthraquinone compound according to claim 2, wherein the branched chain alkyl group is represented by the following formula:

4. R ３ is a methyl group and R ４ is a linear alkyl group having 4 to 7 carbon atoms, or R ３ is an ethyl group or a propyl group, and R ４ The anthraquinone compound according to claim 3, wherein is a linear alkyl group having 3 to 7 carbon atoms.

5. R ２ The anthraquinone compound according to claim 1 , wherein is a linear alkoxy group having 1 to 8 carbon atoms.

6. R ２ The anthraquinone compound according to claim 5, wherein is a linear alkoxy group having 1 to 4 carbon atoms.

7. R ２ The anthraquinone compound according to any one of claims 1 to 4, wherein R is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms.

8. A liquid crystal composition comprising the anthraquinone compound according to claim 1 and a liquid crystal material.

9. The liquid crystal composition according to claim 8 , further comprising a dichroic dye other than the anthraquinone compound represented by formula (A).

10. The liquid crystal composition according to claim 8 or 9, further comprising a photocurable compound and a photopolymerization initiator.

11. A photocured product of the liquid crystal composition according to claim 10.

12. 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 8 or 9 or the cured product according to claim 11 sandwiched between the pair of opposing substrates.

13. The light-adjusting element according to claim 12 , wherein both of the pair of substrates are transparent substrates having transparent electrodes.

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