Liquid crystal composition for light modulation containing anthraquinone compound, photo-cured product thereof, and light modulation element

Abstract

The present application relates to a liquid crystal composition for light adjustment containing an anthraquinone compound having a specific structure as a dichroic dye, and a light adjustment element containing a hardened product of the liquid crystal composition for light adjustment, which is excellent in contrast, light shielding performance, light resistance, and heat resistance under energization. More specifically, the present application relates to a liquid crystal composition for light adjustment containing a compound represented by the following formula (A) (in the formula, R1 represents an alkyl group having 4 to 12 carbon atoms or an alkoxy group having 4 to 12 carbon atoms, and R2 each independently represents an alkyl group having 6 to 12 carbon atoms), a liquid crystal material, a light hardenable compound, and a photopolymerization initiator, and a light adjustment element in which a light hardened product of the liquid crystal composition for light adjustment is interposed between a pair of substrates.

Description

TECHNICAL FIELD

[0001] The present application relates to a liquid crystal composition for light modulation containing an anthraquinone compound, a light hardened product of the liquid crystal composition for light modulation, and a light modulation element using the light hardened product. BACKGROUND

[0002] A light modulation material containing a liquid crystal and a polymer that holds the liquid crystal, when no electric field is applied, the incident light is scattered because the difference between the refractive index of the polymer and the refractive index of the liquid crystal is large, and the liquid crystal layer becomes a hazy state, and if an electric field is applied, the liquid crystal aligns in the direction of the electric field and the difference between the refractive index of the polymer and the refractive index of the liquid crystal becomes small, and becomes a transparent state (Patent Document 1).

[0003] In the windows, doors, and partition boards of vehicles such as electric cars and automobiles, buildings such as business buildings and hospitals, and the like, light modulation films using such properties are being used in place of blinds for the purpose of protecting privacy and the like, and the like are becoming widespread. Generally, such light modulation films can control the penetration or scattering of light by the application or non-application of voltage to shield the view, but cannot shield the light itself, and thus have a tendency to increase glare due to light scattering. Therefore, for the purpose of reducing glare or improving contrast and the like, attempts are being made to use pigments in the material of the light modulation panel. For example, when such a light modulation panel is used in the window glass of an automobile, there is a strong demand for: a clear and good view when transparent, and a light shielding performance that can obtain a low transmittance of about 10% when light shielding; and light resistance or voltage resistance that does not decrease the transmittance even if there is a long time of light irradiation or a long time of voltage application at high temperatures due to the effects of long-term exposure to the outdoors.

[0004] As pigments used in light modulation films, generally dichroic pigments are used. Light modulation elements using liquid crystal compositions containing dichroic pigments are known as GH (Guest Host) type that do not contain polymers, and various dichroic pigments have been proposed (Patent Documents 2 and 3).

[0005] For such dichroic pigments, of course, contrast when manufactured as display elements is required, and light resistance and heat resistance and the like are also required, and efforts are being made to improve these properties. However, in light modulation applications containing polymers and liquid crystals, dichroic pigments that satisfy light shielding performance, contrast, light resistance, and voltage resistance have not been found. For example, in Patent Document 4, a dichroic pigment suitable for light modulation applications containing polymers and liquid crystals has been disclosed, but the pigment of the same document is insufficient in contrast, light resistance, and voltage resistance. In addition, the light modulation material of Patent Document 5 has a transmittance of about 25% or more when light shielding, and the light shielding performance is insufficient.

[0006] [Related Art Documents]

[0007] [Patent Documents]

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 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

[0013] [Problems to be Solved by the Invention]

[0014] An object of the present application is to provide a liquid crystal composition for light adjustment containing an anthraquinone compound having a specific structure as a dichroic dye, and a light adjustment element having a hardened product of the liquid crystal composition for light adjustment, which is excellent in contrast, light shielding property, light resistance, and heat resistance under energization.

[0015] [Means of Solving the Problems]

[0016] As a result of intensive studies by the present inventors, it has been found that the above problems can be solved by using an anthraquinone compound having a specific structure, and the present application has been completed.

[0017] That is, the present application has the following aspects.

[0018] (1). A liquid crystal composition for light adjustment, comprising:

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

[0020]

[0021] (in the formula, R1 represents an alkyl group having 4 to 12 carbon atoms or an alkoxy group having 4 to 12 carbon atoms, and R2 each independently represents an alkyl group having 6 to 12 carbon atoms);

[0022] a liquid crystal material;

[0023] a photo-curable compound; and

[0024] a photopolymerization initiator.

[0025] (2). The liquid crystal composition for light adjustment according to the preceding item (1), wherein R1 in the formula (A) is an alkyl group having 4 to 7 carbon atoms or an alkoxy group having 4 to 7 carbon atoms, and R2 each independently is an alkyl group having 7 to 10 carbon atoms.

[0026] (3) The liquid crystal composition for light modulation according to the preceding item (1), wherein R1 in the formula (A) is an alkyl group having 4 or 5 carbons, and R2 are each independently an alkyl group having 8 to 10 carbons.

[0027] (4) The liquid crystal composition for light modulation according to the preceding item (1), wherein R1 in the formula (A) is an alkyl group having 6 or 7 carbons, and R2 are each independently an alkyl group having 7 to 9 carbons.

[0028] (5) The liquid crystal composition for light modulation according to any one of the preceding items (1) to (4), which comprises one or more dichroic dyes other than the compound represented by the formula (A).

[0029] (6) A photocured product of a liquid crystal composition for light modulation according to any one of the preceding items (1) to (5).

[0030] (7) A light modulation element comprising a photocured product of the liquid crystal composition for light modulation according to the preceding item (6) held between a pair of substrates disposed opposite to each other, wherein at least one of the pair of substrates is a transparent substrate having a transparent electrode.

[0031] (8) The light modulation element according to the preceding item (7), wherein both of the pair of substrates are transparent substrates having a transparent electrode.

[0032] [Effects of the Invention]

[0033] By using the liquid crystal composition for light modulation of the present invention, a light modulation element having excellent light resistance, heat resistance under energization, contrast, and light shielding performance can be obtained. DETAILED DESCRIPTION

[0034] Hereinafter, the present invention will be described in detail.

[0035] The liquid crystal composition for light modulation of the present invention (hereinafter, also simply referred to 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.

[0036] The specific structure compound represented by the formula (A) 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.

[0037]

[0038] In the formula (A), R1 represents an alkyl group having 4 to 12 carbons or an alkoxy group having 4 to 12 carbons, and R2 are each independently an alkyl group having 6 to 12 carbons.

[0039] The alkyl group represented by R1 of formula (A) having a carbon number of 4 to 12 can be any one of linear, branched or cyclic. Specific examples thereof can include n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, t-pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, cyclopentyl, cyclohexyl, 2-ethylhexyl, 2-propylhexyl, 2-butylhexyl, 2-pentylhexyl, 2-pentylheptyl, and the like. Linear or branched alkyl groups having a carbon number of 4 to 10 are preferable, and linear or branched alkyl groups having a carbon number of 4 to 7 are more preferable.

[0040] The alkoxy group represented by R1 of formula (A) having a carbon number of 4 to 12 can be any one of linear or branched. Specific examples thereof can include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, t-butoxy, n-pentoxy, isopentoxy, neopentoxy, t-pentoxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, and the like. Linear or branched alkoxy groups having a carbon number of 4 to 10 are preferable, and linear or branched alkoxy groups having a carbon number of 4 to 7 are more preferable.

[0041] The alkyl group represented by R2 of formula (A) having a carbon number of 6 to 12 can be any one of linear or branched. Specific examples thereof can include the same examples as the linear or branched alkyl groups having a carbon number of 6 to 12 described in the items of the alkyl group represented by R1 of formula (A) having a carbon number of 4 to 12. Linear or branched alkyl groups having a carbon number of 6 to 10 are preferable, and linear or branched alkyl groups having a carbon number of 7 to 10 are more preferable.

[0042] With respect to the combination of R1 and R2 in formula (A), when R1 is an alkyl group having a carbon number of 4 or 5, R2 is preferably independently an alkyl group having a carbon number of 8 to 12, and more preferably an alkyl group having a carbon number of 8 to 10, respectively. When R1 is an alkyl group having a carbon number of 6 or 7, R2 is preferably independently an alkyl group having a carbon number of 6 to 10, and more preferably an alkyl group having a carbon number of 7 to 9, respectively.

[0043] Suitable specific examples of the compound represented by the aforementioned formula (A) can include the following compounds.

[0044]

[0045]

[0046]

[0047]

[0048]

[0049] The compound represented by the formula (A) described above can be synthesized by a method known from the prior art described in, for example, Japanese Patent Application Publication No. 63-90568, and the like.

[0050] When the solubility of the compound represented by the formula (A) in the composition of the present application is defined as "the concentration of the compound represented by the formula (A) with respect to the components other than the compound represented by the formula (A) in the composition obtained by filtering the composition of the present application after stirring all the components of the composition of the present application at 40 to 50°C for 1 hour", 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 the formula (A) in the composition of the present application within the aforementioned range, sufficient pigment additive effects can be obtained, and the polymerization of the photo-curable compound can be prevented when a hardened product is formed by irradiating light to the composition of the present application.

[0051] The liquid crystal material contained in the composition of the present application is not particularly limited as long as it is a material having liquid crystal properties (a compound having liquid crystal properties) such as nematic liquid crystal, cholesteric liquid crystal, and smectic liquid crystal, but nematic liquid crystal is preferred. The compound having liquid crystal properties can be exemplified by the liquid crystal compounds described in, for example, "Handbook of Liquid Crystals" (Committee 142 of the Science Council of Japan, NIKKAN KOGYO SHUPPAN, 1989), items 154 to 192 and items 715 to 722.

[0052] The photo-curable compound contained in the composition of the present application is not particularly limited as long as it is a compound having a functional group that can be polymerized by the action of the photo-polymerization initiator described later when irradiated with light. The photo-curable compound preferably contains both a monofunctional monomer having one polymerizable functional group and a difunctional monomer having two polymerizable functional groups.

[0053] Regarding the monofunctional monomer used as the photo-curable compound in the composition of the present application, it has compatibility with the liquid crystal in the composition before light irradiation, and it forms a hardened product phase by phase separation from the liquid crystal when polymerization is performed by light irradiation, and plays a role of moderating the interfacial interaction with the liquid crystal phase. Therefore, if the polarity of the monofunctional monomer is too high, the interfacial interaction with the liquid crystal phase becomes too strong to hinder the action of the liquid crystal, and a high driving voltage is required. Thus, the polarity of the monofunctional monomer is preferably low.

[0054] As the difunctional monomer used as the photo-curable compound in the composition of the present application, when polymerization is performed by light irradiation, it forms a hardened phase by phase separation from the liquid crystal, and functions to stabilize the state of separation from the liquid crystal phase. Therefore, if the polarity of the difunctional monomer is too high, the interface interaction with the liquid crystal phase becomes too strong, and the movement of the liquid crystal is hindered, necessitating a high driving voltage. Thus, the polarity of the difunctional monomer is preferably low.

[0055] The photo-curable compound can be exemplified by, for example, compounds having a (meth)acrylate group, compounds having a vinyl group, and compounds having an allyl group, etc. Compounds having a (meth)acrylate group are preferred. That is, it is more preferable 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.

[0056] In addition, in the present specification, the notation "(meth)acrylate" means "methacrylate and / or acrylate".

[0057] The mono(meth)acrylate compound preferably has a linear, cyclic or branched alkyl group having a carbon number of 5 to 13. Specific examples thereof can be exemplified by linear mono(meth)acrylate esters 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 mono(meth)acrylate esters such as isobornyl (meth)acrylate; and branched mono(meth)acrylate esters 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, etc.

[0058] The di(meth)acrylate compound can be exemplified by, 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 also triethylene glycol di(meth)acrylate and other trialkylene glycol di(meth)acrylates.

[0059] As for the ratio when a monofunctional monomer and a difunctional monomer are used in combination, the mass ratio of monofunctional monomer : difunctional monomer is preferably 1 : 9 to 9 : 1, and more preferably 5 : 5 to 9 : 1. By setting the amount of use of the monofunctional monomer to the above range of ratio, the compatibility with the liquid crystal does not become too high, and thus the separation of the polymer (polymer phase) formed by light irradiation and the liquid crystal phase is moderately caused, the gelation of only the monomer is prevented, and the separation phase of the polymer phase and the liquid crystal phase is easily formed.

[0060] As for the compatibility of the light-hardening compound and the liquid crystal material contained in the composition of the present application, the phase separation caused by the lowering of the temperature after the light-hardening compound and the liquid crystal material are temporarily made compatible can be visually observed by a polarizing microscope, or the phase separation temperature obtained by the measurement by DSC or the like can be evaluated. The phase separation temperature of the light-hardening 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 light-hardening compound and the liquid crystal material in the composition is good, and the phase separation after the polymerization of the light-hardening compound by light irradiation is not caused, and thus the liquid crystal phase formed as a result does not become too small, and thus the driving voltage can be reduced, and the compatible state of the above components until the light irradiation is easily maintained.

[0061] The photopolymerization initiator contained in the composition of the present application is not particularly limited as long as it is a compound that can polymerize the light-hardening compound by the irradiation of light, and is preferably a compound that does not remain in the hardened product after the light irradiation to cause the deterioration of the dichroic pigment or the like.

[0062] The photopolymerization initiator is preferably an alkylphenol-based photopolymerization initiator such as DAROCUR 1173, IRGACURE 651, IRGACURE 184, or the like, or a phosphine oxide-based photopolymerization initiator such as IRGACURE TPO.

[0063] The content of the compound represented by formula (A) (dichroic pigment) in the composition of the present application is preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the liquid crystal material.

[0064] In addition, when a dichroic pigment other than the compound represented by formula (A) (described later) is used in combination in the composition of the present application, the content of the total of all the dichroic pigments is preferably in the above range (0.5 to 5% by mass).

[0065] The total of the compound represented by formula (A) and the liquid crystal material in the composition of the present application is preferably 90:10 to 50:50, more preferably 80:20 to 50:50, and still more preferably 65:35 to 50:50, by mass ratio, to the photocurable compound. By setting the blending ratio of the photocurable compound to the above range, separation of the liquid crystal material from the photocurable compound before hardening by light irradiation and reduction in light shielding property of the hardened product can be prevented.

[0066] 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 application, the total of the dichroic dyes and the liquid crystal material is preferably in the above range (90:10 to 50:50 by mass ratio) to the photocurable compound, and the more preferable range and the still more preferable range are the same as described above.

[0067] The content of the photopolymerization initiator in the composition of the present application is preferably 0.1 to 5 parts by mass, relative to 100 parts by mass of the photocurable compound.

[0068] By using a dichroic dye other than the compound represented by formula (A) in combination in the composition of the present application, the contrast of the light modulation element at the time of light shielding can be improved.

[0069] The dichroic dye that can be used is not particularly limited, but for example, it can be selected from azo dyes, anthraquinone dyes, perylene dyes, quinophthalone dyes, merocyanine dyes, azomethine dyes, phthaloperene dyes, indigo dyes, azulene dyes, dioxazine dyes, polythiophene dyes, and the like. Specifically, the dyes described in "Dichroic dyes for Liquid Crystal Display" (A. V. Ivashchenko, CRC Press, 1994) and the like can be mentioned.

[0070] Among these, azo dyes, anthraquinone dyes, perylene dyes, or quinophthalone dyes are preferably used in combination, and azo dyes and anthraquinone dyes are more preferably used in combination.

[0071] 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 of the dichroic dyes is not particularly limited as long as it is in a range that does not impair the effects of the present application. The content is preferably 1 to 80 mass%, more preferably 10 to 70 mass%, and still more preferably 30 to 60 mass%.

[0072] In the composition of the present application, in addition to the compound represented by Formula (A) (dichroic pigment), liquid crystal material, photocurable compound, and photopolymerization initiator, a light stabilizer such as a benzotriazole-based, benzophenone-based, and hindered amine-based light stabilizer, an antioxidant such as a phosphite-based and hindered phenol-based antioxidant, a thermal polymerization inhibitor, a mercaptan compound, a photosensitizer, a photosensitizing agent, a chain transfer inhibitor, a polymerization inhibitor, an adhesion-imparting agent, an antifoaming agent, a crosslinking agent, a surfactant, a thermal curing accelerator, a thermoplastic resin, a thermocurable resin, a tackifier such as urethane dipropyl acrylate, and the like can also be used in combination.

[0073] In addition, in order to control the cell gap as the light-adjusting element, a spherical or cylindrical spacer of silica or glass, plastic, ceramic, or the like can also be added. The cell gap at this time can be set to a range of 2 to 100 μm.

[0074] The composition of the present application is obtained by mixing and stirring the compound represented by Formula (A), liquid crystal material, photocurable compound, and photopolymerization initiator, which are essential components, and any component added as necessary. As for the mixing and stirring, the simplest is to place all of the constituent components in a container and stir by hand, but it is more effective to use a machine such as a magnetic stirrer. In addition, in order to efficiently produce a uniform composition, it is preferable to first prepare a uniform mixture of the photocurable compound, photopolymerization initiator, and liquid crystal material, and then add the compound represented by Formula (A) and any component and stir and mix. Heating can also be applied as necessary during the stirring and mixing. The stirring and mixing under a light source that emits light of the absorption wavelength of the photopolymerization initiator is preferably performed for a very short time. After mixing the components, filtration can be performed using a screen, membrane filter, or the like.

[0075] By irradiating light to the composition of the present application, a hardened product of the light-adjusting liquid crystal composition in which the photocurable compound component is hardened (polymerized) can be obtained. In addition, the so-called "hardened product" in the present application means a state in which the functional group of the photocurable compound is polymerized or copolymerized by irradiation of light, and does not mean a hardened product in which the compound represented by Formula (A) or liquid crystal material, or the like necessarily contributes to the hardening reaction.

[0076] The light source at the time of irradiation of light is not particularly limited as long as it is a light source that can irradiate light of a wavelength that is absorbed by the photopolymerization initiator, and a high-pressure mercury lamp, metal halide lamp, xenon lamp, halogen lamp, or the like that can irradiate ultraviolet light can be used as the preferable light source.

[0077] The temperature at the time of irradiation with light is preferably a temperature at which the composition can be maintained in a state of being uniformly mixed, that is, a temperature higher than the phase separation temperature, and is more preferably a temperature in a range of 1 to 5°C higher than the phase separation temperature. By making the temperature at the time of irradiation with light higher than the phase separation temperature, the light-hardening compound and the liquid crystal material can be prevented from being separated before irradiation with light, and a more uniform hardened product can be obtained. On the other hand, by making the temperature at the time of irradiation with light not substantially higher than the phase separation temperature, the size of the domains formed by the liquid crystal material can be prevented from becoming too small at the time of separation between the polymer of the light-hardening compound obtained by light hardening and the liquid crystal material.

[0078] The light-adjusting element of the present application is made by sandwiching a layer of the light-hardened product of the aforementioned light-adjusting liquid crystal composition between a pair of substrates disposed opposite to each other, at least one of the substrates being a transparent substrate having a transparent electrode. Here, the substrate can be exemplified by inorganic transparent materials such as glass or quartz, metals, metal oxides, semiconductors, ceramics, plastic sheets, plastic films, and the like, which are colorless transparent or colored transparent, or non-transparent. The electrode is a thin film of a metal oxide, a metal, a semiconductor, an organic conductive substance, or the like formed on the substrate by a known coating method or printing method or vapor deposition method such as sputtering, or the like, over the entire surface or a part of the substrate. In particular, in order to obtain a light-adjusting element of a large area, from the viewpoints of productivity and workability, it is desirable to use an electrode substrate on which an ITO (indium oxide, tin oxide) electrode has been formed by a vapor deposition method such as sputtering or a printing method, or the like, on a transparent high molecular film such as PET. In addition, a wiring for connecting between electrodes or between an electrode and the outside can be provided on the substrate. For example, it can be an electrode substrate for segment driving or an electrode substrate for matrix driving, an electrode substrate for active matrix driving, or the like. In addition, the entire surface or a part of the electrode provided on the substrate can be covered with a protective film or an alignment film composed of an organic compound such as polyimide or polyamide, polysiloxane, a cyan compound, an inorganic compound such as SiO2, TiO2, ZrO2, or a mixture of these.

[0079] By using a plastic film as the substrate, a light-adjusting element having flexibility and lightness can be obtained. Therefore, the light-adjusting element can be used by being sandwiched between a pair of planar or curved glass or hard plastic substrates, with an adhesive layer of polyvinyl butyral or vinyl acetate, a double-sided adhesive tape, an adhesive, or the like interposed therebetween; or by being attached to the surface of a planar or curved glass or hard plastic substrate with a double-sided adhesive tape or an adhesive, or the like. In addition, the light-adjusting element can be sandwiched between soft plastic substrates, or attached to one or both surfaces. In addition, a hard coat layer, an ultraviolet cut layer or an infrared cut layer, a half mirror, or the like protective layer can be provided on the surface of the substrate opposite to the electrode surface of the light-adjusting element. In addition, a color filter can be laminated on the light-adjusting element, or a polarizing filter can be mounted. In addition, the light-adjusting element can be laminated as a component of an electroluminescent display element, a light-emitting diode display element, an electrochromic display element, or another liquid crystal display element.

[0080] The driving device for applying a voltage to the light adjusting element of the present application is a device that can apply a direct current voltage of 2 to 100 V or an alternating current voltage of 10 to 1000 Hz, and a device that forms an open circuit or a short circuit between electrodes when no voltage is applied, and in addition, the driving device can also have a voltage application circuit for segment driving, a voltage application circuit for matrix driving, a voltage application circuit for active matrix, and the like.

[0081] The light adjusting element of the present application can be either a black light adjusting element or a color light adjusting element depending on the use. The average transmittance of the light adjusting element of the present application at the time of light transmission in a specific wavelength region is preferably 35% or more, more preferably 40% or more. In addition, the average transmittance at the time of light shielding is preferably 25% or less, more preferably 15% or less, and still more preferably 10% or less.

[0082] The black light adjusting element described above has a neutral color and has little color leakage, excellent contrast, and excellent light resistance due to long-term outdoor exposure and power-on heat resistance in the visible light region when no voltage is applied. Therefore, such a black light adjusting element is most suitable for vehicle use or building material use.

[0083] [Examples]

[0084] Hereinafter, the present application will be specifically described by examples. In this document, "parts" and "%" are on a mass basis unless otherwise specified. The maximum absorption wavelength in the examples is a value measured with a spectrophotometer "UV-3150" manufactured by Shimadzu Corporation.

[0085] Synthesis Example 1 (Synthesis of compound represented by formula (3) of specific example)

[0086] To a mixture of 35 parts of sulfolane, 2.8 parts of 1-(4-butylanilino)-5-amino-4,8-dihydroxy-3,7-dibromoanthraquinone was added and dissolved, and then 0.90 parts of potassium carbonate and 4.4 parts of 4-octyloxyphenol 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 crystallized product was filtered, washed with methanol and water, and then dried. The obtained crude product was purified by column chromatography to obtain 1.4 parts of the compound represented by the above formula (3). The maximum absorption wavelength of this compound in toluene was 627 nm.

[0087] Synthesis Example 2 (Synthesis of compound represented by formula (6) of specific example)

[0088] To 1-(4-tert-butylanilino)-5-amino-4,8-dihydroxy-3,7-dibromoanthraquinone 2.8 parts were added in sulfolane 35 parts and dissolved, and then potassium carbonate 0.90 part, 4-heptyloxyphenol 4.2 parts were added, and the reaction was carried out at 130 to 140°C for 5 hours. After the reaction, cooling was carried out, methanol was added, and the crystallized product was filtered, washed with methanol and water, and then dried. The obtained crude product was purified by column chromatography to obtain the compound shown by the above formula (6) 1.3 parts. The maximum absorption wavelength of this compound in toluene was 627 nm.

[0089] Synthesis Example 3 (Synthesis of compound represented by formula (13) of specific example)

[0090] To 1-(4-tert-butylanilino)-5-amino-4,8-dihydroxy-3,7-dibromoanthraquinone 2.8 parts were added in sulfolane 35 parts and dissolved, and then potassium carbonate 0.90 part, 4-heptyloxyphenol 4.2 parts were added, and the reaction was carried out at 130 to 140°C for 5 hours. After the reaction, cooling was carried out, methanol was added, and the crystallized product was filtered, washed with methanol and water, and then dried. The obtained crude product was purified by column chromatography to obtain the compound shown by the above formula (6) 1.3 parts. The maximum absorption wavelength of this compound in toluene was 627 nm.

[0091] Synthesis Example 4 (Synthesis of compound represented by formula (14) of specific example)

[0092] To 1-(4-tert-butylanilino)-5-amino-4,8-dihydroxy-3,7-dibromoanthraquinone 2.8 parts were added in sulfolane 35 parts and dissolved, and then potassium carbonate 0.90 part, 4-heptyloxyphenol 4.2 parts were added, and the reaction was carried out at 130 to 140°C for 5 hours. After the reaction, cooling was carried out, methanol was added, and the crystallized product was filtered, washed with methanol and water, and then dried. The obtained crude product was purified by column chromatography to obtain the compound shown by the above formula (6) 1.3 parts. The maximum absorption wavelength of this compound in toluene was 627 nm.

[0093] Synthesis Example 5 (Synthesis of compound represented by formula (26) of specific example)

[0094] To 1-(4-tert-butylanilino)-5-amino-4,8-dihydroxy-3,7-dibromoanthraquinone 2.8 parts were added in sulfolane 35 parts and dissolved, and then potassium carbonate 0.90 part, 4-heptyloxyphenol 4.2 parts were added, and the reaction was carried out at 130 to 140°C for 5 hours. After the reaction, cooling was carried out, methanol was added, and the crystallized product was filtered, washed with methanol and water, and then dried. The obtained crude product was purified by column chromatography to obtain the compound shown by the above formula (6) 1.3 parts. The maximum absorption wavelength of this compound in toluene was 627 nm.

[0095] Synthesis Example 6 (Synthesis of compound represented by formula (27) of specific example)

[0096] To cyclobutanone 40 parts was added 1-(4-pentylamino)-5-amino-4,8-dihydroxy-3,7- dibromoanthraquinone 2.7 parts and dissolved, and then potassium carbonate 0.90 parts, 4- decyloxyphenol 5.0 parts were added, and reacted at 130 to 140°C for 5 hours. After the reaction, cooling was performed, methanol was added, and the precipitated crystals were filtered, washed with methanol and water, and then dried. The obtained crude product was purified by column chromatography to obtain the compound represented by the above formula (27) 1.2 parts. The maximum absorption wavelength of this compound in toluene was 627 nm.

[0097] Comparative Synthesis Example 1 (Synthesis of compound of comparative example)

[0098] The compound represented by the above formula (X) shown in Example 6 of Japanese Patent Application Laid-Open No. 62-5941 was obtained by a publicly known synthesis method.

[0099]

[0100] Example 1 (Production of liquid crystal composition for light adjustment of the present application)

[0101] The compound represented by the above formula (3) obtained in Synthesis Example 1 0.015 parts, isobornyl acrylate (Osaka Organic Chemical Industry, monoacrylate) 0.380 parts, triethylene glycol dimethacrylate (Shinnihon Chemical Co., Ltd.) 0.020 parts, 1-cyano-4'-n-pentyl biphenyl 0.283 parts, 1-cyano-4'-n-heptyl biphenyl 0.139 parts, 1-cyano-4'-n-octyloxy biphenyl 0.089 parts, 1-cyano-4"-n-pentyl terphenyl 0.089 parts, IRGACURE TPO (BASF Co., Ltd.) 0.004 parts, IRGACURE 184 (BASF Co., Ltd.) 0.004 parts, and a spacer having a diameter of 20 μm (Micropearl (registered trademark) SP220, Seiko Optical Co., Ltd.) 0.010 parts were mixed at room temperature to prepare a liquid crystal composition for light modulation of the present application.

[0102] Examples 2 to 6 and Comparative Example 1 (Production of liquid crystal composition for light adjustment of the present application and comparative example)

[0103] Example 1 except that the compound represented by formula (3) obtained in Synthesis Example 1 was changed to the compound represented by formula (6) obtained in Synthesis Example 2, the compound represented by formula (13) obtained in Synthesis Example 3, the compound represented by formula (14) obtained in Synthesis Example 4, the compound represented by formula (26) obtained in Synthesis Example 5, the compound represented by formula (27) obtained in Synthesis Example 6, and the compound represented by formula (X) obtained in Comparative Synthesis Example 1, respectively, a liquid crystal composition for light modulation of the present application and a comparative liquid crystal composition for light modulation were obtained, respectively, according to Example 1.

[0104] Examples 7 to 12 and Comparative Example 2 (Production of light adjustment element of the present application and comparative example)

[0105] On a 5cm square PET film containing an ITO film, the dimming liquid crystal compositions obtained in Examples 1 to 6 and Comparative Example 1 were applied using an applicator, such that the composition layer on the ITO film was overlapped with the ITO film in the same manner as described above. Afterwards, the sample, maintained at 23°C with a ThermoPlate, was placed under an LED lamp at a 365nm light intensity of 9mW / cm². 2 The location is irradiated with light for 1 minute to photocur the photocurable compound component, thereby obtaining the dimming element of the present invention and the dimming element for comparison.

[0106] (Calculation of transmittance difference of dimming elements)

[0107] For the dimming elements obtained in Examples 7 to 12 and Comparative Example 2, the maximum absorption wavelength was measured, and the transmittance difference (transmittance change) was calculated from the 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 between the transmittance at the maximum absorption wavelength when a voltage is applied and when the maximum absorption wavelength is not applied, using a dimming element manufactured in a manner that makes the transmittance at the maximum absorption wavelength when no voltage is applied (when the light is blocked). As shown in Table 1, it can be seen that the transmittance difference between the dimming elements of Examples 7 to 12 when applied and when no voltage is applied is significantly larger than that of the dimming element of Comparative Example 2. In addition, compared with the dimming element of Example 8 (using the compound shown in formula (6) obtained in Synthesis Example 2), the transmittance difference between the dimming elements of Examples 7 and 9 to 12 when applied and when no voltage is applied is larger.

[0108] [Table 1]

[0109] Table 1 Results of Penetration Difference Measurement

[0110]

[0111]

[0112] (Lightfastness test of dimming elements)

[0113] The dimming elements obtained in Examples 7 to 12 and Comparative Example 2 were bonded to UV cutoff filters with a wavelength below 400 nm, and measurements were taken at 63°C and an illuminance of 600 W / m². 2The absorbance of the maximum absorption wavelength of the metal halogen lamp when irradiated for 24 hours was measured, and the absorbance retention rate ((δA)%) was calculated. The absorbance retention rate ((δA)%) was defined as

[0114] (δA) % = (A(24) / A(0)) x 100.

[0115] The greater the value of δA, the more excellent the light resistance.

[0116] As shown in Table 2, it was confirmed that the absorbance retention rate of the light-adjusting element of Examples 7 to 12 was greater than that of the light-adjusting element of Comparative Example 2, and that the light-adjusting element of Examples 7 to 12 had excellent light resistance. In addition, the absorbance retention rate of the light-adjusting element of Examples 7 and 9 to 12 was greater than that of the light-adjusting element of Example 8 (using the compound represented by formula (6) obtained in Synthesis Example 2), and the light-adjusting element of Examples 7 and 9 to 12 had more excellent light resistance. Among them, the light-adjusting element of Examples 9 to 12 had particularly excellent light resistance, and in particular, the light-adjusting element of Examples 11 and 12 had excellent light resistance.

[0117] [Table 2]

[0118] Table 2 Results of light resistance test

[0119]

[0120]

[0121] Example 13 (Production of black light adjustment element)

[0122] A black light-adjusting element was produced in the same manner as in Example 7 to 12, except that 0.015 parts of LCD212 (anthraquinone compound, manufactured by Wako Pure Chemical Industries, Ltd.) and 0.008 parts of LCD307 (azo compound, manufactured by Wako Pure Chemical Industries, Ltd.) were added. The average transmittance of the obtained black light-adjusting element at an applied voltage of 400 to 700 nm was 38%, the average transmittance without an applied voltage was 9%, and a high transmittance difference was exhibited.

[0123] The black light-adjusting element obtained in Example 13 did not change in transmittance even after 500 hours of xenon light resistance test, and had excellent light resistance to long-term exposure to light. In addition, the transmittance did not change and the current resistance to heat was excellent when a 100 V alternating voltage (50 Hz sine wave) was applied at a temperature of 110°C. From these results, it was shown that the black light-adjusting element of Example 13 was a black liquid crystal light-adjusting element having high contrast and high light-shielding performance, and having light resistance / current resistance to heat.

[0124] By using the liquid crystal composition of the present application, a liquid crystal cell for light control having high contrast / high light shielding performance / high light resistance / high heat resistance under energization can be obtained, and can be suitably used for outdoor building material applications, vehicle-mounted applications, which require high durability.

Claims

1. A liquid crystal composition for dimming, comprising: The compound represented by formula (A) below, In the formula, R1 is an alkyl group with 6 or 7 carbon atoms, and R2 is an alkyl group with 7 to 9 carbon atoms, respectively. liquid crystal materials; Photocurable compounds; and Photopolymerization initiators, among which, The photocurable compound contains monofunctional monomers and difunctional monomers.

2. The dimming liquid crystal composition according to claim 1, wherein, It contains one or more dichroic pigments other than the compound shown in formula (A).

3. A photocurable form of a dimming liquid crystal composition, wherein the dimming liquid crystal composition is the dimming liquid crystal composition according to claim 1 or 2.

4. A dimming element comprising a photocured copy of the dimming liquid crystal composition of claim 3 sandwiched between a pair of opposing substrates, wherein at least one of the pair of substrates is a transparent substrate having a transparent electrode.

5. The dimming element according to claim 4, wherein, Both of the two substrates are transparent substrates with transparent electrodes.

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