Light-adjusting liquid crystal composition containing anthraquinone compound, photocurable product thereof and light-adjusting element

Abstract

The present invention relates to a dimming liquid crystal composition and a dimming element containing a cured product of the dimming liquid crystal composition. The dimming liquid crystal composition contains an anthraquinone compound of a specific structure as a dichroic pigment, and the dimming element has excellent contrast, light-shielding performance, light resistance, and heat resistance when powered on. More specifically, the present invention relates to a dimming liquid crystal composition and a dimming element formed by sandwiching a photocured product of the dimming liquid crystal composition between a pair of substrates. The dimming liquid crystal composition contains a compound represented by the following formula (A) (wherein R 1 represents an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms, R 2 each independently represents an alkyl group having 1 to 8 carbon atoms), a liquid crystal material, a photocurable compound, and a photopolymerization initiator.

Description

Technical Field

[0001] The present invention relates to a light-adjusting liquid crystal composition containing an anthraquinone compound, a photocurable product of the light-adjusting liquid crystal composition, and a light-adjusting element using the photocurable product. Background Art

[0002] A dimming material comprising liquid crystal and a polymer that holds the liquid crystal, when no electric field is applied, the incident light is scattered and the liquid crystal layer becomes blurred due to the large difference between the refractive index of the polymer and the liquid crystal. On the other hand, if an electric field is applied, the liquid crystal will be neatly arranged in the direction of the electric field and the difference between the refractive index of the polymer and the liquid crystal will decrease, thus becoming transparent (Patent Document 1).

[0003] In the windows, doors and partitions of vehicles such as trains and cars, and buildings such as commercial buildings and hospitals, it is becoming common to use dimming films that utilize such properties to replace blinds for the purpose of protecting privacy. Generally, such dimming films can control the penetration or scattering of light by applying voltage to block the field of view, but they cannot block the light itself, so there is a tendency for glare to increase due to light scattering. Therefore, attempts are being made to use pigments in the materials of dimming panels for the purpose of reducing glare or improving contrast. For example, when such a dimming panel is used on the window glass of a car, it is strongly required that: when transparent, it is not blurred and the field of view is good, and when shading, a low transmittance of about 10% can be obtained; and even if there is a long-term exposure to light at high temperature or a long-term voltage application due to the influence of long-term exposure caused by outdoor use, the transmittance does not decrease. Light resistance or electrical heat resistance.

[0004] Dyes used in light-adjusting films are generally dichroic dyes. A light-adjusting element using a liquid crystal composition containing a dichroic dye is known to be a GH (Guest Host) type that does not contain a polymer, and various dichroic dyes have been proposed (Patent Documents 2 and 3).

[0005] For such a dichroic dye, of course, contrast is required when it is made into a display element, and light resistance and heat resistance are also required, and efforts are made to improve these characteristics. However, in the dimming application containing polymers and liquid crystals, no dichroic dye that can meet the light-shielding performance, contrast, light resistance and heat resistance when powered on has been found. For example, in Patent Document 4, a dichroic dye suitable for dimming applications containing polymers and liquid crystals has been disclosed, but the dye in the same document is insufficient in contrast, light resistance and heat resistance when powered on. In addition, the dimming material of Patent Document 5 has a transmittance of about 25% when shading, but the light-shielding performance is insufficient.

[0006] [Prior art literature]

[0007] [Patent Document]

[0008] Patent Document 1: Japanese Patent Publication No. Showa 63-501512

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 62-5941

[0010] Patent Document 3: Japanese Patent Application Laid-Open No. 63-90568

[0011] Patent Document 4: Japanese Patent Application Laid-Open No. 05-224191

[0012] Patent document 5: Japanese Patent Application Laid-Open No. 04-264193. Summary of the invention

[0013] [Problems to be solved by the invention]

[0014] The object of the present invention is to provide a dimming liquid crystal composition and a dimming element containing a cured product of the dimming liquid crystal composition. The dimming liquid crystal composition contains an anthraquinone compound of a specific structure as a dichroic pigment, and the dimming element has excellent contrast, light-shielding performance, light resistance and heat resistance when powered on.

[0015] [Methods to solve the problem]

[0016] As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by using an anthraquinone compound with a specific structure, and have completed the present invention.

[0017] That is, various aspects of the present invention are as follows.

[0018] (1) A dimming liquid crystal composition comprising:

[0019] The compound represented by the following formula (A),

[0020]

[0021] (Where R 1 represents an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms, R 2 each independently represents an alkyl group having 1 to 8 carbon atoms);

[0022] liquid crystal materials;

[0023] Photocurable compounds; and

[0024] Photopolymerization initiator.

[0025] (2) The dimming liquid crystal composition described in the preceding item (1), wherein R in formula (A) 1 It is an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms.

[0026] (3) The light-adjusting liquid crystal composition according to the above item (1) or (2), comprising one or more dichroic dyes other than the compound represented by formula (A).

[0027] (4) A photocured product of a light-adjusting liquid crystal composition, wherein the light-adjusting liquid crystal composition is the light-adjusting liquid crystal composition described in any one of (1) to (3).

[0028] (5) A dimming element, comprising a light-cured material of the liquid crystal composition described in the preceding item (4) sandwiched between a pair of opposing substrates, wherein at least one of the pair of substrates is a transparent substrate having a transparent electrode.

[0029] (6) The light control element described in the above item (5), wherein both of the pair of substrates are transparent substrates having transparent electrodes.

[0030] [Effects of the invention]

[0031] By using the light control liquid crystal composition of the present invention, a light control element having excellent light resistance, heat resistance during conduction, contrast and light shielding performance can be obtained. DETAILED DESCRIPTION

[0032] Hereinafter, the present invention will be described in detail.

[0033] The light-adjusting liquid crystal composition of the present invention (hereinafter, also simply described as “the composition of the present invention”) contains a compound represented by the following formula (A), a liquid crystal material, a photocurable compound, and a photopolymerization initiator.

[0034] The compound having a specific structure represented by formula (A) and having an anthraquinone skeleton as a main skeleton contained in the composition of the present invention functions as a dichroic dye in the composition of the present invention.

[0035]

[0036] In formula (A), R 1 represents an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms, R 2 Each independently represents an alkyl group having 1 to 8 carbon atoms.

[0037] R of formula (A) 1The alkyl group having 1 to 12 carbon atoms represented may be any of straight chain, branched chain or cyclic. Specific examples thereof include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, cyclopentyl, cyclohexyl, 2-ethylhexyl, 2-propylhexyl, 2-butylhexyl, 2-pentylhexyl and 2-pentylheptyl. A straight chain or branched chain alkyl group having 1 to 9 carbon atoms is preferred, and a straight chain or branched chain alkyl group having 1 to 4 carbon atoms is more preferred.

[0038] R of formula (A) 1 The alkoxy group having 1 to 12 carbon atoms represented may be any of a straight chain or a branched chain. Specific examples thereof include: methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, isopentoxy, neopentoxy, tert-pentoxy, hexoxy, heptoxy, octoxy, nonyloxy, decyloxy, undecyloxy, and dodecyloxy. A straight chain or branched chain alkoxy group having 1 to 10 carbon atoms is preferred, and a straight chain or branched chain alkoxy group having 1 to 4 carbon atoms is more preferred.

[0039] R of formula (A) 2 The alkyl group having 1 to 8 carbon atoms represented by may be either linear or branched. Specific examples thereof include the following: 1 The linear or branched alkyl groups having 1 to 8 carbon atoms described in the items of the alkyl groups having 1 to 12 carbon atoms are the same examples. The linear or branched alkyl groups having 1 to 7 carbon atoms are preferred, and the linear alkyl groups having 3 to 7 carbon atoms are more preferred.

[0040] Preferred specific examples of the compound represented by the above formula (A) include the following compounds.

[0041]

[0042]

[0043]

[0044]

[0045]

[0046] The compound represented by the above formula (A) can be synthesized by a conventionally known method described in, for example, JP-A-63-90568.

[0047] When the solubility of the compound represented by formula (A) in the composition of the present invention is defined as "the concentration of the compound represented by formula (A) relative to the components other than the compound represented by formula (A) in the composition obtained by stirring all the components of the composition of the present invention at 40 to 50° C. for 1 hour and filtering", the concentration is preferably 0.5 to 10% by mass, and more preferably 1.0 to 6.0% by mass. By setting the solubility of the compound represented by formula (A) in the composition of the present invention to the above range, a sufficient pigment addition effect can be obtained, and the polymerization inhibition of the photocurable compound when the composition of the present invention is irradiated with light to form a cured product can be prevented.

[0048] The liquid crystal material contained in the composition of the present invention is not particularly limited as long as it is a material (compound with liquid crystal) having liquid crystal properties such as nematic liquid crystal, cholesteric liquid crystal, smectic liquid crystal, etc., but nematic liquid crystal is preferred. The compound with liquid crystal properties can be listed, for example, in the liquid crystal compounds described in Items 154 to 192 and Items 715 to 722 of the "Liquid Crystal Device Handbook" (Compiled by the 142nd Committee of the Japan Society for the Promotion of Science, Nikkan Kogyo Shimbun, 1989).

[0049] The photocurable compound 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. The photocurable compound is preferably a monofunctional monomer having one polymerizable functional group and a difunctional monomer having two polymerizable functional groups.

[0050] Regarding the monofunctional monomer used as a photocurable compound in the composition of the present invention, it has compatibility with liquid crystal in the composition before light irradiation, and when polymerized by light irradiation, it separates from the liquid crystal to form a hardened phase, and plays a role in relieving the interface interaction with the liquid crystal phase. Therefore, if the polarity of the monofunctional monomer is too high, the interface interaction with the liquid crystal phase becomes too strong and hinders the movement of the liquid crystal, and a high driving voltage is required. Therefore, the polarity of the monofunctional monomer is preferably low polarity.

[0051] Regarding the bifunctional monomer used as a photocurable compound in the composition of the present invention, when polymerized by light irradiation, it separates from the liquid crystal to form a hardened phase, and plays a role in stabilizing the separation state from the liquid crystal phase. Therefore, if the polarity of the bifunctional monomer is too high, the interface interaction with the liquid crystal phase becomes too strong, hindering the movement of the liquid crystal, and a high driving voltage is required. Therefore, the polarity of the bifunctional monomer is preferably low.

[0052] 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. That is, it is more preferred to use both a mono(meth)acrylate compound having one (meth)acrylate group in one molecule and a di(meth)acrylate compound having two (meth)acrylate groups in one molecule.

[0053] In addition, the description of "(meth)acrylate" in this specification means "methacrylate and / or acrylate".

[0054] 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.

[0055] As the di(meth)acrylate compound, for example, 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, and trialkylene glycol di(meth)acrylates such as triethylene glycol di(meth)acrylate can be preferably used.

[0056] Regarding the ratio when using a monofunctional monomer and a difunctional monomer together, the mass ratio of the monofunctional monomer: the difunctional monomer is preferably 1:9 to 9:1, and 5:5 to 9:1 is more preferred. By setting the amount of the monofunctional monomer used to the aforementioned ratio range, the compatibility with the liquid crystal will not become too high, so that the separation of the polymer (polymer phase) formed by light irradiation and the liquid crystal phase will be appropriately generated, and the gelation of only the monomer can be prevented, and the separation phase of the polymer phase and the liquid crystal phase can be easily formed.

[0057] Regarding the compatibility of the photocurable compound contained in the composition of the present invention with the liquid crystal material, the phase separation caused by the decrease in temperature can be visually observed through a polarizing microscope after temporarily making the photocurable compound and the liquid crystal material compatible; or it can be evaluated based on the phase separation temperature obtained by measurement such as DSC. The phase separation temperature of the photocurable compound and the liquid crystal material is preferably in the range of 0 to 50°C, and more preferably in the range of 10 to 40°C. By setting the phase separation temperature to the above range, the compatibility of the photocurable compound and the liquid crystal material in the composition is good, and phase separation after polymerization of the photocurable compound by light irradiation does not occur. Accordingly, the resulting liquid crystal phase will not become too small, so the driving voltage can be reduced, and it is easy to maintain the compatible state of the above components until light irradiation.

[0058] The photopolymerization initiator contained in the composition of the present invention is not particularly limited as long as it is a compound that can polymerize the photocurable compound by irradiation with light, and is preferably a compound that does not remain in the cured product after irradiation with light to cause deterioration of the dichroic dye or the like.

[0059] As the photopolymerization initiator, for example, an alkylphenol-based photopolymerization initiator such as DAROCUR 1173, IRGACURE 651, or IRGACURE 184, or a phosphine oxide-based photopolymerization initiator such as IRGACURE TPO is preferably used.

[0060] The content of the compound (dichroic dye) represented by formula (A) in the composition of the present invention is preferably 0.5 to 5 parts by mass based on 100 parts by mass of the liquid crystal material.

[0061] When a dichroic dye (described later) other than the compound represented by formula (A) is used in combination in the composition of the present invention, the total content of all dichroic dyes is preferably within the above range (0.5 to 5% by mass).

[0062] The blending ratio of the total of the compound represented by formula (A) and the liquid crystal material to the photocurable compound in the composition of the present invention is preferably 90:10 to 50:50 in terms of mass ratio, 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 to the above range, it is possible to prevent the liquid crystal material and the photocurable compound from being separated before curing by light irradiation, and to prevent the light shielding property of the cured product from being reduced.

[0063] In addition, when a dichroic dye (described later) other than the compound represented by formula (A) is used in combination in the composition of the present invention, the mixing ratio of the total of all dichroic dyes and liquid crystal materials to the photocurable compound is preferably in the above-mentioned range (90:10 to 50:50 in terms of mass ratio), and the more preferred range and the even more preferred range are also the same as above.

[0064] The content of the photopolymerization initiator in the composition of the present invention is preferably 0.1 to 5 parts by mass based on 100 parts by mass of the photocurable compound.

[0065] 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-adjusting element during light shielding can be improved.

[0066] The dichroic pigments that can be used in combination are not particularly limited, but for example, they can be selected from azo pigments, anthraquinone pigments, perylene pigments, quinophthalone pigments, merocyanine pigments, azomethine pigments, phthaloyl pigments, indigo pigments, azulene pigments, dioxazine pigments, polythiophene pigments, etc. Specifically, the pigments described in "Dichroic dyes for Liquid Crystal Display" (AVIvashchenko's work, CRC Company, 1994) can be cited.

[0067] Among these, it is preferable to use an azo dye, an anthraquinone dye, a perylene dye, or a quinoline yellow dye in combination, and it is more preferable to use an azo dye and an anthraquinone dye in combination.

[0068] 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 dye is not particularly limited as long as it is within the range that does not impair the effect of the present invention. The content is preferably 1 to 80% by mass, more preferably 10 to 70% by mass, and even more preferably 30 to 60% by mass.

[0069] In the composition of the present invention, in addition to the compound represented by formula (A) (dichroic dye), liquid crystal material, photocurable compound and photopolymerization initiator, for example, light stabilizers such as benzotriazole-based, benzophenone-based and hindered amine-based, antioxidants such as phosphite-based and hindered phenol-based, thermal polymerization inhibitors, thiol compounds, photosensitizers, photosensitizers, chain transfer inhibitors, polymerization inhibitors, adhesion-imparting agents, defoaming agents, crosslinking agents, surfactants, heat-curing accelerators, thermoplastic resins, heat-curing resins, tackifiers such as urethane diacrylates, etc. can also be used in combination.

[0070] In addition, in order to control the cell gap as a light-adjusting element, a spherical or cylindrical spacer made of silicon dioxide, glass, plastic, ceramic, etc. may be added. In this case, the cell gap can be set in the range of 2 to 100 μm.

[0071] The composition of the present invention is obtained by mixing and stirring the compound represented by formula (A) which is an essential component, a liquid crystal material, a photocurable compound and a photopolymerization initiator, and any component added as needed. Regarding mixing and stirring, the simplest method is to place all the constituent components in a container and stir them manually, but it is more effective to stir them using a machine such as a magnetic stirrer. In addition, in order to efficiently prepare a uniform composition, it is preferred to first modulate a uniform mixture of a photocurable compound, a photopolymerization initiator and a liquid crystal material, and then add the compound represented by formula (A) and any component and stir and mix them. It is also acceptable to apply heating as needed during stirring and mixing. Stirring and mixing under a light source that emits the absorption wavelength of the photopolymerization initiator is preferably performed in a very short time. After mixing the components, filtering is performed using a sieve, a membrane filter, etc.

[0072] By irradiating the composition of the present invention with light, a cured product of the light-adjusting liquid crystal composition in which the photocurable compound component is cured (polymerized) can be obtained. In addition, the so-called "cured product" in the present invention means a state in which the functional groups of the photocurable compound are polymerized or copolymerized by irradiation with light, and does not mean a cured product in which the compound represented by formula (A) or the liquid crystal material necessarily contributes to the curing reaction.

[0073] The light source for irradiation is not particularly limited as long as it can irradiate 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 that can irradiate ultraviolet rays.

[0074] The temperature during light irradiation is preferably a temperature that can maintain a uniformly intermixed state of the composition, that is, a temperature higher than the phase separation temperature, and more preferably a temperature range of 1 to 5°C higher than the phase separation temperature. By setting the temperature during light irradiation higher than the phase separation temperature, the photocurable compound and the liquid crystal material can be prevented from separating before light irradiation, and a more uniform cured product can be obtained. On the other hand, by not setting the temperature during light irradiation significantly higher than the phase separation temperature, when the polymer of the photocurable compound obtained by light curing separates from the liquid crystal material, the domain size formed by the liquid crystal material can be prevented from becoming too small.

[0075] The dimming element of the present invention is formed by sandwiching a layer of a photocured material of the dimming liquid crystal composition between a pair of substrates arranged opposite to each other, and at least one of the substrates is a transparent substrate having a transparent electrode. Here, the substrate may be a colorless, transparent, colored, transparent, or opaque material such as glass or quartz, a metal, a metal oxide, a semiconductor, a ceramic, a plastic plate, or a plastic film. The electrode is a thin film of a metal oxide, a metal, a semiconductor, an organic conductive material, etc. formed on the entire or a part of the substrate by a known coating method, a printing method, or a vapor deposition method such as sputtering. In particular, in order to obtain a large-area dimming element, it is desirable to use an electrode substrate having an ITO (indium oxide, tin oxide) electrode formed on a transparent polymer film such as PET by a vapor deposition method such as sputtering or a printing method, etc., from the perspective of productivity and processability. In addition, wiring for connecting electrodes or electrodes to the outside may also be provided on the substrate. For example, it may be an electrode substrate for segment driving, an electrode substrate for matrix driving, an electrode substrate for active matrix driving, etc. Alternatively, an organic compound such as polyimide, polyamide, polysilicon, or cyanide, SiO 2 、TiO 2 、ZrO 2 The protective film or oriented film composed of inorganic compounds such as , or a mixture of these covers the entire surface or a part of it.

[0076] By using a plastic film as a substrate, a flexible and lightweight dimming element can be obtained. Therefore, the dimming element can be used by sandwiching a bonding layer of polyvinyl butyral or vinyl acetate, double-sided tape, adhesive, etc. between a pair of flat or curved glass or hard plastic substrates; or the dimming element can be pasted on the surface of a flat or curved glass or hard plastic substrate with double-sided tape or adhesive. In addition, it can also be sandwiched between soft plastic substrates, or pasted on one or both sides. In addition, a hard coating, an ultraviolet cutoff layer or an infrared cutoff layer, a half mirror, or other protective layers can also be provided on the substrate surface on the opposite side of the electrode surface of the dimming element. In addition, a color filter can be stacked on the dimming element, or a polarizing filter can be installed. In addition, the dimming element can also be stacked as a component of an electroluminescent display element, a light-emitting diode display element, an electrochromic display element, or other liquid crystal display elements.

[0077] The driving device used to apply voltage to the dimming element of the present invention can be any device that can apply a DC voltage of 2 to 100V or an AC voltage of 10 to 1000Hz, and can form an open circuit or a short circuit between electrodes when no voltage is applied. In addition, the driving device may also have a voltage application circuit for segment driving, a voltage application circuit for matrix driving, a voltage application circuit for active matrix, etc.

[0078] The dimming element of the present invention may be either a black dimming element or a color dimming element according to the application. The average transmittance of the dimming element of the present invention when light is transmitted in a specific wavelength region is preferably 35% or more, and more preferably 40% or more. In addition, the average transmittance when shielding light is preferably 25% or less, and more preferably 15% or less.

[0079] The black dimming element has a neutral color and has little color leakage in the visible light region when no voltage is applied, has excellent contrast, and has excellent light resistance and electrical heat resistance due to long-term outdoor exposure. Therefore, such a black dimming element is most suitable for automotive use or building material use.

[0080] [Example]

[0081] The present invention is specifically described below by way of examples. In addition, "parts" and "%" herein are by mass unless otherwise specified. The maximum absorption wavelength in the examples is a value measured by a spectrophotometer "UV-3150 manufactured by Shimadzu Corporation".

[0082] Synthesis Example 1 (Synthesis of a Compound Represented by Formula (1) of a Specific Example)

[0083] 2.7 parts of 1-(4-butylanilino)-5-amino-4,8-dihydroxy-3,7-dibromoanthraquinone were added to 35 parts of sulfolane and dissolved, and then 0.90 parts of potassium carbonate and 4.2 parts of 4-(4-pentylcyclohexyl)phenol were added and reacted at 130 to 140°C for 5 hours. After the reaction, the mixture was cooled, methanol was added, and the precipitated crystals were filtered to obtain 1.2 parts of the compound represented by the above formula (1). The maximum absorption wavelength of the compound in toluene is 621 nm.

[0084] Synthesis Example 2 (Synthesis of the Compound Represented by Formula (4) of Specific Example)

[0085] 3.0 parts of 1-(4-butylanilino)-5-amino-4,8-dihydroxy-3,7-dibromoanthraquinone were added to 35 parts of sulfolane and dissolved, and then 0.90 parts of potassium carbonate and 4.7 parts of 4-(4-heptylcyclohexyl)phenol were added and reacted at 130 to 140°C for 5 hours. After the reaction, the mixture was cooled, methanol was added, and the precipitated crystals were filtered to obtain 1.0 parts of the compound represented by the above formula (4). The maximum absorption wavelength of the compound in toluene is 622 nm.

[0086] Synthesis Example 3 (Synthesis of the Compound Represented by Formula (10) of Specific Example)

[0087] 3.0 parts of 1-(4-tert-butylanilino)-5-amino-4,8-dihydroxy-3,7-dibromoanthraquinone were added to 35 parts of sulfolane and dissolved, and then 0.90 parts of potassium carbonate and 4.7 parts of 4-(4-propylcyclohexyl)phenol were added, and the mixture was reacted at 130 to 140°C for 5 hours. After the reaction, the mixture was cooled, methanol was added, and the precipitated crystals were filtered to obtain 1.0 parts of the compound represented by the above formula (10). The maximum absorption wavelength of the compound in toluene is 622 nm.

[0088] Comparative Synthesis Example 1 (Synthesis of Compounds for Comparative Example)

[0089] The compound shown in Example 6 of JP-A-62-5941 (the compound represented by the following formula (X)) was obtained by a publicly known synthesis method.

[0090]

[0091] Example 1 (Preparation of the Light-Adjusting Liquid Crystal Composition of the Present Invention)

[0092] 0.013 parts of the compound represented by the above formula (1) obtained in Synthesis 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.), 0.283 parts of 1-cyano-4'-n-pentylbiphenyl, 0.139 parts of 1-cyano-4'-n-heptylbiphenyl, 0.089 parts of 1-cyano-4'-n-octyloxybiphenyl, 0.089 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 having a diameter of 20 μm (Micropearl (registered trademark) SP220 manufactured by Sekisui Chemical Co., Ltd.) were mixed at room temperature to prepare a light-adjusting liquid crystal composition of the present invention.

[0093] Examples 2, 3 and Comparative Example 1 (Preparation of the Light-Adjusting Liquid Crystal Compositions of the Invention and Comparative Examples)

[0094] Except that the compound represented by formula (1) obtained in Synthesis Example 1 is changed to the compound represented by formula (4) obtained in Synthesis Example 2, the compound represented by formula (10) obtained in Synthesis Example 3 and the compound represented by formula (X) obtained in Comparative Synthesis Example 1, the rest is based on Example 1 to obtain the dimming liquid crystal composition of the present invention and the comparative dimming liquid crystal composition, respectively.

[0095] Examples 4 to 6 and Comparative Example 2 (Fabrication of the Dimming Components of the Invention and Comparative Examples)

[0096] On the 5 cm square PET film with ITO film, the dimming liquid crystal composition obtained in Examples 1 to 3 and Comparative Example 1 was applied using an applicator, respectively, so that the composition layer on the ITO film and the ITO film were overlapped with the 5 cm square PET film with ITO film as described above. After that, the sample was maintained at 23°C by a heating plate (ThermoPlate) and placed under the light intensity of 365nm of the LED lamp to become 9mW / cm 2 The position was irradiated with light for 1 minute to photocure the photocurable compound component, thereby obtaining a dimming element of the present invention and a comparative dimming element.

[0097] (Calculation of the transmittance difference of the dimming element)

[0098] For the dimming elements obtained in Examples 4 to 6 and Comparative Example 2, the maximum absorption wavelength was measured, and the transmittance difference (transmittance change) was calculated from the measurement results of the transmittance (%) at the maximum absorption wavelength when a 100V AC voltage (50Hz sine wave) was applied and when no voltage was applied. The transmittance difference is a value calculated from the difference in transmittance at the maximum absorption wavelength when a voltage is applied, using a dimming element manufactured in a manner such that the transmittance at the maximum absorption wavelength when no voltage is applied (when shielded) is equal. As shown in Table 1, it can be seen that the transmittance difference between the dimming elements of Examples 4 to 6 when a voltage is applied and when no voltage is applied is significantly larger than that of the dimming element of Comparative Example 2.

[0099] [Table 1]

[0100] Table 1 Transmission rate difference measurement results

[0101]

[0102] (Light resistance test of dimming components)

[0103] The dimming elements obtained in Examples 4 to 6 and Comparative Example 2 were bonded with UV cut filters of 400 nm or less, and the light intensity was measured at 63°C and an illumination of 600 W / m 2 The absorbance retention rate ((δA)%) was calculated by measuring the absorbance at the maximum absorption wavelength after irradiation with a metal halide lamp for 24 hours. The absorbance retention rate ((δA)%) is defined as A(0) at 0 hours and A(24) at 24 hours.

[0104] (δA)%=(A(24) / A(0))×100.

[0105] The larger the value of δA is, the better the light resistance is.

[0106] As shown in Table 2, it can be confirmed that the light control elements of Examples 4 to 6 have a larger absorbance retention rate than the light control element of Comparative Example 2 and have excellent light resistance.

[0107] [Table 2]

[0108] Table 2 Lightfastness test results

[0109]

[0110] Example 7 (Fabrication of Black Dimming Element)

[0111] The black dimming element was prepared in the same manner as in Examples 4 to 6 using the dimming liquid crystal composition of the present invention prepared in the same manner as in Example 1, except that the compound represented by formula (1) was changed from 0.013 parts to 0.015 parts, and 0.01 parts of LCD212 (anthraquinone compound, manufactured by Nippon Kayaku Co., Ltd.) and 0.005 parts of LCD307 (anthraquinone compound, manufactured by Nippon Kayaku Co., Ltd.) were added. The obtained black dimming element had an average transmittance of 42% when a voltage was applied at 400 to 700 nm, an average transmittance of 14% when no voltage was applied, and showed a high transmittance difference.

[0112] The black dimming element obtained in Example 7 has no change in transmittance after 500 hours of xenon light resistance test, and has excellent light resistance when exposed to light for a long time. In addition, when 100V AC voltage (50Hz sine wave) is applied at 110°C, the transmittance does not change and the heat resistance during power on is also excellent. From these results, it is shown that the black dimming element of Example 7 is a black liquid crystal dimming element with high contrast and high light shielding performance and light resistance / heat resistance during power on.

[0113] By using the liquid crystal composition of the present invention, a dimming liquid crystal element having high contrast / high light-shielding performance / high light resistance / high heat resistance when powered on can be obtained, and can be suitably used in outdoor building materials and vehicle applications requiring high durability.

Claims

1. A dimming liquid crystal composition comprising: The compound represented by the following formula (A), In the formula, R 1 represents an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 12 carbon atoms, R 2 Each independently represents an alkyl group having 1 to 8 carbon atoms; liquid crystal materials; Photocurable compounds; and Photopolymerization initiator.

2. The dimming liquid crystal composition according to claim 1, in, R in formula (A) 1 It is an alkoxy group having 1 to 4 carbon atoms. 3 . The light-adjusting liquid crystal composition according to claim 1 , comprising one or more dichroic dyes other than the compound represented by formula (A).

4. A light-cured liquid crystal composition for dimming, in, The light-adjusting liquid crystal composition is the light-adjusting liquid crystal composition according to any one of claims 1 to 3.

5. A light-adjusting element, comprising a pair of substrates disposed opposite to each other and sandwiching a photocured material of the light-adjusting liquid crystal composition according to claim 4, wherein at least one of the pair of substrates is a transparent substrate having a transparent electrode.

6. The dimming element according to claim 5, in, Both of the pair of substrates are transparent substrates having transparent electrodes.

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