Anthraquinone compound, liquid crystal composition containing said compound, and dimming 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

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

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

[0002] Various light-controlling films that control the transmission of external light for purposes such as privacy protection have been proposed for use 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 the light itself, and therefore tend to increase glare due to light scattering. 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 windowpanes, 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 upon application of current. Although efforts have been made to improve these properties, none have been found that satisfy the contrast, light fastness, and heat resistance upon application of current. 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 upon application of current.

[0005] JP 63-501512 JP 03-47392 JP 2018-205746 JP 2011-190314 JP 63-72760 JP 62-101657 EP59036A1

[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 that is the novel anthraquinone compound, a liquid crystal composition containing the anthraquinone compound, and a light-controlling device containing the composition and having excellent contrast, light fastness, and heat resistance when electricity is applied.

[0007] The present inventors have succeeded in obtaining a novel anthraquinone compound having a specific structure. Furthermore, the present inventors have discovered 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 device having excellent contrast, light fastness, and heat resistance upon application of electricity can be obtained. Specifically, the various aspects encompassed by the present invention are as follows: [1]. A compound represented by the following formula (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): (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): (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 formula (1).) An anthraquinone compound represented by the formula (2). ２is a substituent represented by formula (a), and R in formula (a) ３ [3] The anthraquinone compound according to the above item [1], wherein R 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 is a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms. ２ is a substituent represented by formula (b), and R in formula (b) ５ [5] The anthraquinone compound according to the above item [1], wherein R in formula (1) is a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms. １ [6]. The anthraquinone compound according to any one of [1] to [4] above, wherein R in formula (1) is a linear or branched alkoxy group having 1 to 8 carbon atoms. １ [7]. The anthraquinone compound according to the above item [5], wherein R in formula (1) is a linear alkoxy group having 4 to 8 carbon atoms. １ [8] The anthraquinone compound according to any one of the above items [1] to [4], wherein R in formula (1) is a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms. 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 anthraquinone compounds ...

[0008] According to the present invention, a novel anthraquinone compound is provided. In addition, by using a 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.

[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]

[0011] In formula (1), 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. １ The alkyl group having 1 to 12 carbon atoms represented by 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, 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] R in formula (1) １The alkoxy group having 1 to 12 carbon atoms represented by may be either linear or branched. 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] R in formula (1) 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), R ２ represents a substituent represented by the following formula (a) or (b).

[0015]

[0016] 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 straight or branched alkyl group having 1 to 8 carbon atoms.

[0017] R in formula (a) ３The alkyl group having 1 to 8 carbon atoms represented by may be either linear or branched. Specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a neo-pentyl group, a t-pentyl group, a hexyl group, a heptyl group, an octyl group, and a 2-ethylhexyl group. 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] R in formula (a) ３ The alkoxy group having 1 to 8 carbon atoms represented by may be either linear or branched. 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, and a 2-ethylhexyloxy group. 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] R in formula (a) ３ 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] R in formula (a) ３ The substituent represented by -CH ２ OR ４ R in ４The alkyl group having 1 to 8 carbon atoms represented by may be either linear or branched. Specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a neo-pentyl group, a t-pentyl group, a hexyl group, a heptyl group, an octyl group, and a 2-ethylhexyl group. 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), 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 structure represented by ６ represents a straight or branched alkyl group having 1 to 8 carbon atoms.

[0022] R in formula (b) ５ The alkyl group having 1 to 8 carbon atoms represented by may be either linear or branched. Specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a neo-pentyl group, a t-pentyl group, a hexyl group, a heptyl group, an octyl group, and a 2-ethylhexyl group. 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] R in formula (b) ５ is preferably a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms.

[0024] R in formula (b) ５ The substituent represented by -CH ２ OR ６ R in ６The alkyl group having 1 to 8 carbon atoms represented by may be either linear or branched. Specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a neo-pentyl group, a t-pentyl group, a hexyl group, a heptyl group, an octyl group, and a 2-ethylhexyl group. 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] R in formula (1) ２ As the substituent, a substituent represented by formula (a) is preferred.

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

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

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

[0034] The anthraquinone compound represented by formula (1) of the present invention 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 the anthraquinone compound (dichroic dye) represented by formula (1): S=(A ／／ -A ⊥ ) / (2A ⊥ +A ／／) In the formula, “A ／／ " and "A ⊥ " indicates 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 the device is made into 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 ratio 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, and more 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 (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-mentioned range (0.5 to 10 parts by mass relative to 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 the compound having liquid crystal properties include the liquid crystal compounds described in pages 154 to 192 and 715 to 722 of "Liquid Crystal Device Handbook" (edited by the 142nd Committee of the Japan Society for the Promotion of Science, Nikkan Kogyo Shimbun, 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, and the like.

[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. Preferably, it 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 Darocure 1173, Irgacure 651, Irgacure 184, and phosphine oxide-based photopolymerization initiators such as Irgacure TPO are preferably used.

[0045] In the composition of the present invention containing a photocurable compound and a photopolymerization initiator, the blending ratio of the photocurable compound to the total of the anthraquinone compound represented by Formula (1) and the liquid crystal material 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, 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 can be prevented. When a dichroic dye (described below) other than the compound represented by Formula (1) is used in combination, the blending ratio of the photocurable compound to the total of all dichroic dyes and liquid crystal materials, including the anthraquinone compound represented by Formula (1), in the composition of the present invention is preferably within the above range (90:10 to 50:50 by mass). The more preferred and even more preferred ranges are the same as those described 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 can be used in combination with 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, and the like. Specific examples include those described in "Dichroic Dyes for Liquid Crystal Display" (A.V. Ivashchenko, 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 dyes 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 light stabilizers such as benzotriazoles, benzophenones, and hindered amines, antioxidants such as phosphites and hindered phenols, thermal polymerization inhibitors, thiol compounds, photosensitizers, photosensitizers, chain transfer inhibitors, polymerization inhibitors, adhesion promoters, antifoaming agents, crosslinking agents, surfactants, thermosetting accelerators, thermoplastic resins, thermosetting resins, thickeners such as urethane diacrylate, etc. Furthermore, to control the cell gap of the light-controlling element, spherical or cylindrical spacers such as silica, glass, plastic, and ceramic may be added. The cell gap in this case can be set in the range of 2 to 100 μm.

[0050] The composition of the present invention can be 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 of the 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, the photopolymerization initiator, and the 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). In the present invention, the term "cured product" refers to a state in which the functional group of the photocurable compound is polymerized or copolymerized by light irradiation, and does not necessarily refer to a cured product in which the anthraquinone compound represented by formula (1) or the liquid crystal material, etc., has contributed to the curing reaction. The light source used 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, halogen lamps, etc., 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, for example, forming a thin film of a metal oxide, metal, semiconductor, or organic conductive material over the entire surface or a portion 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 is coated with organic compounds such as polyimide, polyamide, silicone, cyanide compounds, SiO ２ , TiO ２ , ZrO ２ The entire surface or a part of the surface may be covered with a protective film or an alignment film made of an inorganic compound such as those mentioned above, or a mixture thereof.

[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 electrical current even after long-term outdoor exposure. Therefore, the light-controlling device is ideal for use in vehicles or building materials.

[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 anthraquinone compound of the present invention represented by formula (1)) (Step 1-1) Synthesis of intermediate compound represented by the following formula (2) 10.0 parts of 1,5-dichloroanthraquinone, 7.3 parts of potassium carbonate, and 6.0 parts of 4-hydroxybenzenethiol were added to 120 parts of DMF, 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 (2).

[0058]

[0059] (Step 1-2) Synthesis of intermediate compound represented by the following formula (3) 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 to 70 parts of DMF, 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 the following formula (3).

[0060]

[0061] Step (1-3) Synthesis of Compound Represented by Specific Example 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 the mixture was stirred at 100°C for 2 hours. The reaction solution was then cooled to 25°C, and 200 parts of methanol was added, followed by stirring 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 subjected to column purification using toluene as a developing solvent. The solvent was removed from the purified solution by distillation under reduced pressure, and the mixture was dried in a hot air dryer at 80°C for 24 hours, yielding 4.0 parts of the compound represented by Specific Example No. 7 as an orange solid. The maximum absorption wavelength of this compound in methanol was 449 nm.

[0062] Example 2 (Synthesis of anthraquinone compound of the present invention represented by formula (1)) Step (2-1) Synthesis of compound represented by specific example No. 10 3.3 parts of the compound represented by the above specific example No. 10 were obtained as an orange solid in the same manner as in Example 1, 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. The maximum absorption wavelength of this compound in methanol was 450 nm.

[0063] Example 3 (Synthesis of anthraquinone compound of the present invention represented by formula (1)) (Step 3-1) Synthesis of compound represented by specific example No. 15 3.5 parts of the compound represented by the above specific example No. 15 were obtained as an orange solid in the same manner as in Example 1, except that 5.7 parts of 4-octylbenzenethiol in step 1-2 was changed to 4.3 parts of 4-t-butylbenzenethiol, and 2.2 parts of benzyl bromide in step 1-3 was changed to 2.4 parts of 4-t-butylbenzyl chloride. The maximum absorption wavelength of this compound in methanol was 450 nm.

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

[0065] Example 5 (Synthesis of anthraquinone compound of the present invention represented by formula (1)) (Step 5-1) Synthesis of compound represented by specific example No. 48 3.9 parts of the compound represented by the above specific example No. 48 were obtained as an orange solid in the same manner as in Example 1, except that 5.7 parts of 4-octylbenzenethiol in step 1-2 was changed to 5.9 parts of 4-octyloxybenzenethiol, and 2.2 parts of benzyl bromide in step 1-3 was changed to 2.4 parts of 4-t-butylbenzyl chloride. 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]

[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]

[0070] Synthesis Example 3 (Synthesis of Comparative Compound) The compound represented by Example 11 of EP 59036 A1 (compound represented by the following formula (Z)) was obtained by a known synthesis method.

[0071]

[0072] Example 6 (Preparation of Liquid Crystal Composition of the Present Invention) 0.003 parts of the compound represented by Specific Example No. 7 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 were mixed at room temperature to prepare a liquid crystal composition of the present invention.

[0073] Examples 7 to 10 and Comparative Examples 1 to 3 (Preparation of Liquid Crystal Compositions of the Present Invention and Comparative Examples) Liquid crystal compositions of the present invention and comparative liquid crystal compositions 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, and the compound represented by Formula (Z) obtained in Synthesis Example 3, respectively.

[0074] The liquid crystal composition obtained in Example 6 was sealed in a device having a transparent electrode and 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 the light-controlling elements of the present invention and comparative examples) The light-controlling elements of the present invention and comparative examples 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 Parameter of Light-Adjusting Device) The maximum absorption wavelength and order parameter were measured for the light-adjusting devices 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-adjusting devices. From the spectra obtained at that time, the absorbance (A ／／ ), and absorbance (A ⊥ ) was measured, and the order parameter (S value) at the maximum absorption wavelength where the polarization degree ρ was maximum was calculated using the following formula. The results are shown in Table 1. S=(A ／／ -A ⊥ ) / (2A ⊥ +A ／／ )

[0077]

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

[0079] Example 16 (Preparation of Liquid Crystal Composition of the Present Invention) No. 1 of the specific examples obtained in Example 2 was used. 0.01 parts of the compound represented by No. 10, isobornyl acrylate (manufactured by Osaka Organic Chemical Industry, monoacrylate) 0.380 parts, triethylene glycol dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.020 parts, 1-cyano-4'-n-pentylbiphenyl 0.306 parts, 1-cyano-4'-n-heptylbiphenyl 0.15 parts, 1-cyano-4'-n-octyloxybiphenyl 0.096 parts, 1-cyano-4''-n-pentylterphenyl 0.048 parts, Irgacure TPO (manufactured by BASF Corporation) 0.004 parts, Irgacure 184 (manufactured by BASF Corporation) 0.004 parts, and a diameter of 20 μm spacer agent (manufactured by Sekisui Chemical Co., Ltd. "Micropearl (registered trademark) SP220") 0.010 parts were mixed at room temperature and stirred at 50 ° C. for 2 hours. Next, the mixture 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) Liquid crystal compositions of the present invention and comparative examples 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 control elements of the present invention and comparative examples) The liquid crystal compositions obtained in Examples 16 to 18 and Comparative Example 7 were applied to the ITO film of a 5 cm square PET film provided with an ITO film using an applicator, respectively, 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 and the ITO film faced each other. Thereafter, while maintaining the thus obtained sample of the laminate of the two films and the liquid crystal composition layer at 23°C on a thermoplate, the sample was heated to 1000°C under a light intensity of 9 mW / cm at 365 nm from an LED lamp. ２The 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 Light-Adjusting Element) For the light-adjusting elements obtained in Examples 19 to 21 and Comparative Example 8, the maximum absorption wavelength was measured by the above-described 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]

[0084] As shown in Table 2, it is clear that the light control elements 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 element of Comparative Example 8.

[0085] Example 22 (Preparation of black photochromic element) A black photochromic element was prepared 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 photochromic element obtained in Example 22 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. Furthermore, even when a 100 V AC (50 Hz sine wave) voltage was applied under conditions of 110°C, there was no change in transmittance, and the element also showed excellent heat resistance when energized. These results demonstrate that the black photochromic element of Example 22 is a black liquid crystal photochromic element with high contrast, excellent light resistance, and excellent heat resistance when energized. Possible industrial applications

[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) 【Chemistry 1】 (In the formula, R １ R 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 the formula: ４ represents a straight 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 the formula: ６ represents a straight or branched alkyl group having 1 to 8 carbon atoms. represents a substituent represented by the 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 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 R 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 R is a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms.

8. R in formula (1) １ 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 comprising 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 comprising 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, as well as 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 light control 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 them.

17. The light control 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 a pair of substrates are transparent substrates having transparent electrodes.

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