TWI738959B - Liquid crystal element and its manufacturing method and display device - Google Patents

Abstract

The liquid crystal element includes: a pair of substrates arranged in opposite directions; a pair of transparent electrodes arranged on the surfaces of the pair of substrates facing each other; a liquid crystal layer, arranged between the pair of substrates, and will contain liquid crystal and polymerizable The liquid crystal composition of the compound is cured and formed; and the liquid crystal alignment film is formed on the electrode arrangement surface of at least one of the pair of base materials. The liquid crystal composition contains at least one selected from the group consisting of a monofunctional (meth)acrylate compound, a multifunctional (meth)acrylate compound, a multifunctional thiol compound, and a styrene compound as a polymerizable compound. The liquid crystal alignment film is formed of a liquid crystal alignment agent containing poly(meth)acrylate.

Description

Liquid crystal element and its manufacturing method and display device

The present disclosure relates to a liquid crystal element, a manufacturing method thereof, and a display device.

[Cross-reference of related applications]

This application is based on the Japanese application number 2017-10532 filed on January 24, 2017, and the content of the description is cited in this application.

As a liquid crystal element, a polymer dispersion type liquid crystal element has been known in recent years. In the polymer dispersed liquid crystal element, a liquid crystal layer containing a composite material of liquid crystal and a polymer is arranged between a pair of film substrates with transparent electrodes formed on the surface, and it is proposed to use the polymer dispersed liquid crystal element as Dimming element (for example, refer to Patent Document 1 or Patent Document 2). The dimming elements of Patent Document 1 and Patent Document 2 exhibit a dimming function by changing the transparency of the transparent electrode by switching between voltage application and no voltage application. In addition, studies have been conducted to use the dimming function to provide new functions to shop windows, smart phones, televisions, monitors, buildings, furniture, and the like. As a polymer dispersed liquid crystal, for example, a polymer dispersed liquid crystal (Polymer Dispersed Liquid Cristal, PDLC) or a polymer network liquid crystal (Polymer Network Liquid Cristal, PNLC), etc. are known.

Patent Document 3 proposes to arrange a liquid crystal display on the back of a transparent display containing an organic electroluminescence (EL) element. The display device of the display panel. It is proposed that in the display device, the light transmittance is controlled by controlling the voltage applied to the liquid crystal display panel, thereby improving the visibility of the display of the transparent display. In addition, Patent Document 4 discloses an inverted type liquid crystal element in which light passes through a pair of electrodes and becomes a transparent state when no voltage is applied between a pair of electrodes, and light is scattered when a voltage is applied to become a non-transparent state. . The reverse type liquid crystal element described in Patent Document 4 has a polyimide film as an alignment film for vertically aligning liquid crystals, and the alignment state of liquid crystal molecules in the liquid crystal layer is controlled by the polyimide film.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2013-3319

[Patent Document 2] Japanese Patent Laid-Open No. 2013-148744

[Patent Document 3] Japanese Patent Laid-Open No. 2008-083510

[Patent Document 4] International Publication No. 2015/022980

From the viewpoint of ensuring liquid crystal alignment and electrical characteristics in the design of alignment film materials in liquid crystal display panels such as liquid crystal televisions, polyimide-based materials have previously been effectively used. On the other hand, in the liquid crystal display panel and the dimming element, the priority of various characteristics required for the liquid crystal alignment film is different. For example, when used as a dimming element, compared to characteristics related to display quality, such as liquid crystal orientation and electrical characteristics, liquid crystal elements are required to be thinner or have excellent shape diversity.

As one of the methods for improving the thickness reduction and the variety of shapes of the liquid crystal element, the thickness reduction of the base material and the expansion of the range of material selection can be cited. For example, the application of a base material containing a polymer material is considered. In addition, in order to be applicable to a substrate containing a polymer material, the polymer used as an alignment film material is required to have excellent solubility in low-boiling solvents. However, polyimide-based resins are generally difficult to dissolve in low-boiling solvents, and the resulting coating film may have uneven film thickness, uneven coating, and many pinholes, which may make it impossible to obtain a homogeneous liquid crystal alignment film.

In addition, a liquid crystal alignment film using a polyimide-based resin is easily colored, and when it is applied to a dimming element, transparency in a light-transmitting state sometimes becomes a problem. Furthermore, it is assumed that the dimmer element is used for outdoor use, and therefore, it is sometimes required to be excellent in weather resistance.

The present disclosure is made in view of the subject, and the main purpose of the present disclosure is to provide a liquid crystal element. When a substrate containing a polymer material is used for the liquid crystal element, the liquid crystal alignment film is homogeneous and has high transparency, light transmission characteristics and light It has good scattering properties, shows sufficient electrical properties on the basis of realizing the dimming function, and has excellent weather resistance.

The present disclosure adopts the following means in order to solve the above-mentioned problems.

[1] A liquid crystal element, comprising: a pair of substrates arranged oppositely; electrodes, respectively arranged on the surfaces of the pair of substrates facing each other; a liquid crystal layer arranged between the pair of substrates, And it is formed by curing a liquid crystal composition containing a liquid crystal and a polymerizable compound; and a liquid crystal alignment film is formed on the electrode arrangement surface of at least one of the pair of base materials; the liquid crystal composition contains one selected from the group consisting of Functional (meth)propylene At least one of the group consisting of an acid ester compound, a multifunctional (meth)acrylate compound, a multifunctional thiol compound, and a styrenic compound is used as the polymerizable compound; the liquid crystal alignment film is composed of a poly( The meth)acrylate liquid crystal alignment agent is formed.

[2] A display device, comprising: the liquid crystal element described in [1]; and a transparent display that is transparent in a non-display state.

[3] A liquid crystal alignment agent for forming a liquid crystal alignment film of a liquid crystal element, the liquid crystal element having a liquid crystal and A liquid crystal layer formed by curing a liquid crystal composition of a polymerizable compound, and the liquid crystal alignment agent contains poly(meth)acrylate.

[4] A method of manufacturing a liquid crystal element, the liquid crystal element is provided between a pair of substrates arranged such that electrodes provided on the surfaces of each substrate face each other by curing a liquid crystal composition containing a liquid crystal and a polymerizable compound. The liquid crystal layer is formed, and the method for manufacturing the liquid crystal element includes: coating a liquid crystal alignment agent on the electrode arrangement surface of at least one of the pair of substrates to form a liquid crystal alignment film; and forming the liquid crystal After the alignment film is formed, the pair of substrates are arranged so that the electrodes face each other through the layer containing the liquid crystal composition to construct a liquid crystal cell; and after constructing the liquid crystal cell, the polymerizable The step of curing the compound; the liquid crystal composition contains selected from the group consisting of a monofunctional (meth)acrylate compound, a multifunctional (meth)acrylate compound, a multifunctional thiol compound, and a styrenic compound At least one as the polymerizable compound; the liquid crystal alignment agent contains poly(meth)acrylate.

According to the above configuration, when a base material containing a polymer material is used as a pair of base materials, a liquid crystal element having a homogeneous and highly transparent liquid crystal alignment film can also be obtained. In addition, in the case of applying a substrate containing a polymer material, a liquid crystal element having good light transmission characteristics and light scattering characteristics, exhibiting sufficient electrical characteristics while realizing a dimming function, and excellent weather resistance can also be obtained.

10: Liquid crystal element

11: The first substrate

12: The second substrate

13: liquid crystal layer

13a: polymer

13b: Liquid crystal molecules

14, 15: Liquid crystal alignment film

16, 17: transparent electrode

20: display device

30: Transparent display

Fig. 1 is a diagram showing a schematic configuration of a liquid crystal element.

Fig. 2 (a) and Fig. 2 (b) are diagrams illustrating the function of the liquid crystal element.

Fig. 3 is a diagram showing a schematic configuration of a display device including a liquid crystal element and a transparent display.

Hereinafter, the embodiment will be described with reference to the drawings.

<Liquid crystal element>

As shown in FIG. 1, the liquid crystal element 10 of this embodiment includes a pair of substrates composed of a first substrate 11 and a second substrate 12, and a pair of substrates arranged between the first substrate 11 and the second substrate 12. Liquid crystal layer 13. The liquid crystal layer 13 is a polymer dispersion type liquid crystal layer which is a polymer/liquid crystal composite layer formed by mixing polymer 13a and liquid crystal molecules 13b. In this embodiment, it is a polymer in which a polymer network is formed. Dispersed liquid crystal (PDLC). The liquid crystal element 10 is a dimming element that switches the transmitted light by using an electric field to control the alignment of the liquid crystal molecules 13b present in the polymer network Transmissive state and non-transmitting state that scatters light.

The first substrate 11 and the second substrate 12 are transparent substrates containing a polymer material. Examples of polymer materials constituting the base material include: silicon, polyethylene terephthalate, polybutylene terephthalate, polyether agglomerate, polycarbonate, polypropylene, polyvinyl chloride, aromatics Polyamide, polyamide imide, polyimide, triacetyl cellulose (Triacetyl Cellulose, TAC), polymethyl methacrylate and other materials. Furthermore, the first base material 11 and the second base material 12 may also be glass substrates, and in order to realize the thinning and weight reduction of the liquid crystal element, plastic substrates are particularly preferred.

In the first base material 11 and the second base material 12, a transparent electrode 16 and a transparent electrode 17 are respectively arranged on surfaces facing each other, and an electrode pair is constructed by the transparent electrode 16 and the transparent electrode 17. In this embodiment, the transparent electrode 16 and the transparent electrode 17 are transparent conductive films, such as _{NESA film containing tin oxide (SnO 2} ) (registered trademark of PPG in the United States), and indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ) indium tin oxide (Indium Tin Oxid, ITO) film, or a film containing a carbon material. In addition, the transparent electrode 16 and the transparent electrode 17 may have a predetermined pattern, such as a comb-tooth shape, for example.

A liquid crystal alignment film 14 and a liquid crystal alignment film 15 are formed on the respective electrode arrangement surfaces of the first substrate 11 and the second substrate 12. The liquid crystal alignment film 14 and the liquid crystal alignment film 15 are organic thin films that define the alignment orientation of liquid crystal molecules in the liquid crystal layer 13. Alignment film. Furthermore, the liquid crystal alignment film 14 and the liquid crystal alignment film 15 only need to be provided on at least one of a pair of substrates, but from the viewpoint of alignment stability, they are preferably provided on two substrates. The liquid crystal layer 13 is formed by a pair of substrates and sealing After disposing the liquid crystal composition in the space surrounded by the agent (not shown), the liquid crystal composition is cured and the sealing compound is disposed between the pair of base materials so as to surround the outer edge of the electrode disposition surface. The liquid crystal composition contains a liquid crystal and a polymerizable compound.

Furthermore, the liquid crystal element 10 does not have a polarizing plate on the outer surfaces of the first base material 11 and the second base material 12. Therefore, it is excellent in terms of low light absorption loss and high light utilization efficiency.

FIG. 2(a) and FIG. 2(b) are diagrams for explaining the function of the liquid crystal element 10. 2(a) shows a state where no voltage is applied between the transparent electrode 16 and the transparent electrode 17; FIG. 2(b) shows a state where a voltage is applied between the transparent electrode 16 and the transparent electrode 17. The liquid crystal element 10 is an inverted PDLC. In the state where no voltage is applied between the transparent electrode 16 and the transparent electrode 17, incident light passes through one of the pair of substrates and becomes transparent; 16. When a voltage is applied between the transparent electrodes 17, when the alignment state of the liquid crystal molecules 13b changes, incident light is scattered and becomes a non-transparent state. In this embodiment, as shown in FIG. 2(a), when no voltage is applied, the long axis direction of the liquid crystal molecules 13b becomes a direction perpendicular to the substrate surface, and the liquid crystal element 10 becomes a transparent state. As shown in FIG. 2(b), in a state where a voltage is applied, the liquid crystal element 10 becomes a non-transparent state by rotating the liquid crystal molecules 13b in a direction parallel to the substrate surface. By switching the application/non-application of the voltage, the liquid crystal element 10 exhibits a dimming function. The liquid crystal element 10 has a film shape or a plate shape, for example. Furthermore, the liquid crystal element 10 may have a variable light transmittance according to the applied voltage.

<Liquid crystal composition>

Next, the liquid crystal composition used in the formation of the liquid crystal layer 13 will be described. The liquid crystal composition contains a liquid crystal and a polymerizable compound. Examples of the liquid crystal include nematic liquid crystal and discotic liquid crystal.

The polymerizable compound is preferably a compound exhibiting radical polymerizability, and particularly preferably includes a compound selected from a monofunctional (meth)acrylate compound, a polyfunctional (meth)acrylate compound, a polyfunctional thiol compound, and benzene At least one compound in the group consisting of vinyl compounds (hereinafter also referred to as "specific polymerizable compound"). In addition, in this specification, "(meth)acrylate" means acrylate and methacrylate are included.

As specific examples of polymerizable compounds, monofunctional (meth)acrylate compounds include, for example, (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, and (meth)acrylic acid. Tertiary butyl ester, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate and other alkyl (meth)acrylates; cyclohexyl (meth)acrylate, isopropyl (meth)acrylate Cycloalkyl (meth)acrylates such as bornyl ester; aryl (meth)acrylates such as benzyl (meth)acrylate; 2-methoxyethyl (meth)acrylate, (meth)acrylic acid 3 -Methoxybutyl ester, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, 2-phenylphenoxyethyl (meth)acrylate, methoxy Triethylene glycol (meth)acrylate, ethoxylated o-phenylphenol (meth)acrylate, ethyl diethylene glycol (meth)acrylate, glycidyl (meth)acrylate, (meth) Base) Ether-based (meth)acrylates such as tetrahydrofurfuryl acrylate; Alcohol-based (meth)acrylates such as 2-hydroxyethyl (meth)acrylate; 2-(methyl) Carboxylic acid (meth)acrylates such as acryloxyethyl succinic acid and 2-(meth)acryloxyethylhexahydrophthalic acid: acrylamide, (meth)acrylamide Nitrogen-containing unsaturated compounds such as morpholine, isobutoxymethyl(meth)acrylamide, vinylcaprolactam, N-vinyl-2-pyrrolidone; tetrabromobenzene (meth)acrylate Halogenated (meth)acrylates such as esters and pentachlorophenyl (meth)acrylate; 3-(meth)acryloxypropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane Etc.; polyfunctional (meth)acrylate compounds include, for example, ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, 1,6 -Hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, (meth)acryloxy trimethylacetoxy (meth)acryloxy trimethylethyl Ester, 2-hydroxy-3-acryloxypropyl (meth)acrylate, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,9-nonane Alcohol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, three Methylolpropane (meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, di-trimethylolpropane tetra(meth)acrylate, (meth)acrylic amine group Formate compounds (for example, phenyl glycidyl ether (meth)acrylate hexamethylene diisocyanate carbamate prepolymer, pentaerythritol tri(meth)acrylate hexamethylene diisocyanate carbamate Acid ester prepolymer, dipentaerythritol penta(meth)acrylate hexamethylene diisocyanate), etc.; examples of polyfunctional thiol compounds include: 1,3-propane dithiol, 1,4-butane disulfide Alcohol, 1,6-hexanedithiol, 2,5-hexanedithiol, 1,8-octanedithiol, 1,9-nonane dithiol, 3,7-dithio-1,9-nonane dithiol, 1,4-bis(3-mercaptobutoxy)butane, tetraethylene glycol bis (3-mercaptopropionate), dimercaptobenzene, 1,2-bis(mercaptomethyl)benzene, 1,3-bis(mercaptomethyl)benzene, 1,4-bis(mercaptomethyl)benzene, 1 ,3-Dimercapto-5-methyl-benzene, 4,5-dimercapto-1,3,4-thiadiazole, 1,4-bis(2-mercaptoethyl)benzene, carboxyl containing thiol group Dithiol compounds such as esters of acids and glycols; isocyanuric acid, trimercaptobenzene, 2,4,6-trimercapto-1,3,5-triazine, 1,3,5-triazine (3-Mercaptobutyroxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolpropane tris(3-mercaptobutyrate) ), trimethylolpropane tris(3-mercaptopropionate), tris-[(3-mercaptopropionoxy)-ethyl]-isocyanurate, trimethylolethane tris(3 -Mercaptobutyrate), pentaerythritol tetra(3-mercaptobutyrate), pentaerythritol tetra(3-mercaptopropionate), dipentaerythritol hexa(3-mercaptopropionate), multifunctional polymerization with thiol group (For example, Thiokol LP (registered trademark), polythiol (registered trademark) (the above are manufactured by Toray Fine Chemicals Co., Ltd.) in terms of trade names), carboxylic acid containing thiol group Polythiol compounds such as polyesters with polyhydric alcohols, etc.; examples of styrene-based compounds include styrene and methylstyrene.

The polymerizable compound may be used singly, but from the viewpoint of improving the optical properties, it is preferable to use two or more types in combination. Specifically, the liquid crystal composition preferably contains a monofunctional (meth)acrylate compound and a polyfunctional (meth)acrylate compound as the polymerizable compound, and more preferably contains a monofunctional (meth)acrylate compound and a polyfunctional (meth)acrylate compound. Functional (meth)acrylate compounds and multifunctional thiol compounds. Moreover, it is especially preferable to contain a (meth)acrylate urethane compound as at least a part of a monofunctional (meth)acrylate compound and a polyfunctional (meth)acrylate compound.

The content ratio of the polymerizable compound in the liquid crystal composition can be appropriately selected according to the kind of compound. For example, the content ratio of the monofunctional (meth)acrylate compound is preferably 10 parts by mass to 300 parts by mass relative to 100 parts by mass of the total liquid crystal, and more preferably 20 parts by mass to 200 parts by mass. The content ratio of the polyfunctional (meth)acrylate compound is preferably 1 part by mass to 200 parts by mass, and more preferably 5 parts by mass to 100 parts by mass with respect to 100 parts by mass in total of the liquid crystal.

In addition, when the (meth)acrylate urethane compound is contained, the content ratio is preferably 1 part by mass to 150 parts by mass relative to 100 parts by mass of the total liquid crystal, more preferably 5 Parts by mass ~ 100 parts by mass.

The content ratio of the polyfunctional thiol compound is preferably 0.5 parts by mass to 50 parts by mass, and more preferably 1 part by mass to 40 parts by mass with respect to 100 parts by mass in total of the liquid crystal. The blending ratio of the styrene-based compound is preferably from 0.1 parts by mass to 30 parts by mass, and more preferably from 0.5 parts by mass to 20 parts by mass with respect to 100 parts by mass in total of the liquid crystal.

The content ratio of the polymerizable compound in the liquid crystal composition (the total amount when two or more are contained) is preferably 1% by mass to 90% by mass relative to the total amount of the liquid crystal and the polymerizable compound. Preferably, it is set to 5 mass%-80 mass %, and it is more preferable to set it as 10 mass%-75 mass %.

The use ratio of the specific polymerizable compound is preferably 70% by mass or more with respect to the entire polymerizable compound contained in the liquid crystal composition, more preferably 80% by mass or more, and still more preferably 90% by mass or more . The polymerizable compound contained in the liquid crystal composition particularly preferably contains a specific polymerizable compound.

The liquid crystal composition may contain other components other than the liquid crystal and the polymerizable compound. From the viewpoint of further improving the polymerizability of the polymerizable compound and promoting the formation of the polymer network in the liquid crystal layer 13 (preferably on the entire liquid crystal layer 13), it is preferable to contain a polymerization initiator as another component .

The polymerization initiator contained in the liquid crystal composition is preferably a compound (photoinitiator) that can initiate polymerization of a polymerizable compound by irradiation with radiation such as visible light, ultraviolet, extreme ultraviolet, electron beam, and X-ray. The photoinitiator is preferably a radical polymerization initiator that can generate free radicals by light irradiation, and specific examples thereof include acetophenone, benzophenone, and 2-benzyl Benzoic acid, 4,4'-bis(diethylamino)benzophenone, 2-methoxy-2-phenylacetophenone, 2-isobutoxy-2-phenylacetophenone, 2-(1,3-benzodioxan-5-yl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-methyl-1-[4-( (Methylthio)phenyl)-2-morpholin-1-propanone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylbenzene Ethyl ketone, benzaldehyde, fen, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4 , 4'-Diaminobenzophenone, benzyl dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 2,2- Dimethoxy-1,2-diphenylethane-1-one, 2-isopropylthioxanthone, 2-chlorothioxanthone, diphenyl(2,4,6-trimethoxybenzyl) Phosphine oxide, bis-(2,6-dimethoxybenzyl)-2,4,4-trimethylpentyl phosphine oxide, 2-hydroxy-1-[4-[4-( 2-Hydroxy-2-methylpropanyl)benzyl)phenyl)-2-methylpropane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinyl) Phenyl)-butanone-1, 2,4,6-trimethylbenzyl-diphenylphosphine oxide, 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzyl oxime)], ethyl ketone, 1-[9-ethyl-6-(2-methylbenzyl)-9H-carbazole-3- Base)-,1-(O-acetyloxime), 4,4'-bis(diethylamino)benzophenone, 4-(diethylamino)benzophenone, 2-hydroxy -2-Phenylacetophenone, 4,4'-dimethoxybenzyl, diphenylethylenedione, 2-benzyl-2-(dimethylamino)-1-[4-(? (Hydroxy)phenyl]-1-butanone and the like.

From the standpoint of rapidly advancing the curing reaction and suppressing the decrease in curability caused by the addition of an excess amount, the content of the polymerization initiator in the liquid crystal composition is preferably other than the solvent contained in the liquid crystal composition. The total mass of the components (solid content) of is 0.1% by mass to 10% by mass, more preferably 0.5% by mass to 8% by mass, and still more preferably 1% by mass to 7% by mass. In addition, the polymerization initiator may be used singly or in combination of two or more.

As other components blended in the liquid crystal composition, dyes can also be used. By using a dye, the liquid crystal element 10 in which the dye is dispersed in the liquid crystal layer 13 can be obtained. In addition, according to the liquid crystal element 10 of the present disclosure, when the dye is dispersed in the liquid crystal layer 13, the change in light-shielding property/transmittance caused by the switching between voltage application and non-application is also clear. In addition, when driving repeatedly Durability is also good, which is better in this respect.

As the dye, a dichroic dye can be preferably used. The dichroic dye used is not particularly limited, and known compounds can be suitably used. Examples thereof include polyiodine, azo compounds, anthraquinone compounds, and dioxazine compounds. Among these, in terms of excellent light resistance and high dichroic ratio, at least one selected from the group consisting of azo compounds and anthraquinone compounds is preferred, and azo compounds are particularly preferred. In addition, one kind of coloring matter may be used alone, or two or more kinds may be combined.

The blending ratio of the pigment (the total amount in the case of blending two or more) is preferably set relative to the total mass of the solid content in the liquid crystal composition 0.05% by mass to 5% by mass, more preferably 0.1% by mass to 3% by mass.

The liquid crystal composition is prepared by mixing a liquid crystal, a polymerizable compound, and other components added as necessary. The treatment of mixing these components may be performed at room temperature, or may be performed while raising the temperature. In addition, each component may be dissolved in an appropriate organic solvent, and then the solvent may be removed by, for example, a distillation operation.

<Liquid crystal alignment agent>

Next, the liquid crystal alignment agent used to form the liquid crystal alignment film 14 and the liquid crystal alignment film 15 will be described. The liquid crystal alignment agent contains poly(meth)acrylate as a polymer component. In addition, in this specification, "poly(meth)acrylate" means including polyacrylate and polymethacrylate.

(Poly(meth)acrylate)

Examples of the poly(meth)acrylate include reacting a monomer having a (meth)acrylic acid group (hereinafter, also referred to as "(meth)acrylic monomer") in the presence of a polymerization initiator Methods. Regarding the poly(meth)acrylate used in the preparation of the liquid crystal alignment agent, the use ratio of the (meth)acrylic monomer to the total amount of the monomer used in the polymerization is preferably 20% by mass or more, and more It is preferably 30% by mass or more, more preferably 40% by mass or more, and particularly preferably 50% by mass or more.

The (meth)acrylic monomer used in the polymerization is not particularly limited, and examples include (meth)acrylic acid, α-ethyl acrylate, maleic acid, fumaric acid, itaconic acid, and vinyl benzoate. Unsaturated carboxylic acids; methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, allyl (meth)acrylate, (meth)acrylate )Cyclohexyl acrylate, tricyclo[5.2.1.0 ^2,6 ]dec-8-yl (meth)acrylate, dicyclopentyl (meth)acrylate, benzyl (meth)acrylate, (meth)acrylic acid -2-ethylhexyl ester, lauryl (meth)acrylate, trimethoxysilylpropyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, (meth)acrylic acid 2,2,3,3,3-Pentafluoropropyl, methoxyethyl (meth)acrylate, -N,N-dimethylaminoethyl (meth)acrylate, methyl (meth)acrylate Polyoxyethylene glycol, tetrahydrofurfuryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate, 3,4-epoxy (meth)acrylate Unsaturated carboxylic acid esters such as hexyl methyl ester, 3,4-epoxybutyl (meth)acrylate, 4-hydroxybutyl glycidyl acrylate; maleic anhydride, itaconic anhydride, cis-1,2,3 , 4-Tetrahydrophthalic anhydride and other unsaturated polycarboxylic acid anhydrides. In addition, (meth)acrylic monomer can be used individually by 1 type or in combination of 2 or more types.

From the viewpoint of improving the liquid crystal alignment and electrical properties of the obtained liquid crystal element 10, and the adhesion of the liquid crystal alignment film to the substrate, the (meth)acrylic monomer used in the polymerization preferably includes The (meth)acrylic monomer of oxy group. The ratio of the (meth)acrylic monomer having an epoxy group is preferably 1% by mass or more with respect to the total amount of the monomer used in the polymerization, more preferably 5% by mass or more, and further Preferably, it is set to 10% by mass or more.

In addition, at the time of polymerization, monomers other than the (meth)acrylic monomers may also be used. Examples of other monomers include: conjugated diene compounds such as 1,3-butadiene and 2-methyl-1,3-butadiene; styrene, methylstyrene, divinylbenzene, etc. Aromatic vinyl compounds; compounds containing maleimide groups, etc. The ratio of other monomers is preferably set to 80% by mass or less, more preferably 70% by mass or less, with respect to the total amount of monomers used in the synthesis of poly(meth)acrylate. More preferably, it is set to 60% by mass or less.

The poly(meth)acrylate contained in the liquid crystal alignment agent preferably does not contain the side chain structure contained in the group consisting of (a) to (e) shown below (hereinafter, also referred to as "specific Side chain structure").

(a) Alkyl groups with 8 to 22 carbons

(b) Fluorinated alkyl group with 6 to 18 carbon atoms

(c) A group formed by bonding any one of a benzene ring, a cyclohexane ring, and a heterocyclic ring to a C 1-20 alkyl group or a fluorine-containing alkyl group

(d) Groups having a total of two or more at least one ring selected from the group consisting of benzene ring, cyclohexane ring and heterocyclic ring

(e) A group with 17 to 51 carbon atoms with a steroid skeleton

As a specific example of the specific side chain structure, the alkyl group of (a) includes, for example, n-octyl, n-nonyl, n-decyl, n-dodecyl, n-tridecyl, n-tetradecyl, n- Heptadecyl, n-octadecyl, etc.; (b) the fluorine-containing alkyl group includes, for example, a group in which at least one hydrogen atom of the (a) alkyl group is substituted with a fluorine atom; (c) The group and the group of (d) include, for example, the group represented by the following formula (5), and the group of (e) includes, for example, a cholesteryl group, a cholesterol group, and a lanostyl group.

(In formula (5), A ¹ to A ³ are each independently a phenylene group or a cyclohexene group, and may have a substituent in the ring part. R ²¹ is a hydrogen atom, an alkyl group with 1 to 20 carbons, and a carbon number 1-20 alkoxy group, fluorine-containing alkyl group with 1-20 carbon atoms in which at least one hydrogen atom is substituted by fluorine atom, fluorine-containing alkoxy group with 1-20 carbon atoms or fluorine in which at least one hydrogen atom is substituted by fluorine atom Atoms, R ²² and R ²³ are each independently a single bond, -O-, -COO-, -OCO- or alkanediyl group with 1 to 3 carbons. k, m and n satisfy 1≦k+m+n ≦4 is an integer of 0 or more. When R ²¹ is a hydrogen atom, an alkyl group with 1 to 3 carbon atoms, or a fluorine atom, it satisfies k+m+n≧2. "*" indicates a bonding bond)

As specific examples of the group represented by the formula (5), for example, groups represented by the following formulas (5-1) to (5-10) can be cited, but are not limited to these. Examples of the substituent that A ¹ to A ³ may have in the ring portion include a fluorine atom, an alkyl group having 1 to 3 carbon atoms, and an alkoxy group having 1 to 3 carbon atoms. k+m+n is preferably an integer of 2-4.

[化2]

(In the formula, "*" represents the bonding key)

The polymerization reaction using the (meth)acrylic monomer is preferably carried out by radical polymerization. Examples of the polymerization initiator used in the polymerization reaction include: 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile) , 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) and other azo compounds; benzyl peroxide, lauryl peroxide, trimethyl acetic acid peroxide Organic peroxides such as tertiary butyl ester and 1,1'-bis(tertiary butylperoxy)cyclohexane; hydrogen peroxide; redox initiators containing these peroxides and reducing agents, etc. . Among these, azo compound is preferred Things. The polymerization initiator can be used singly or in combination of two or more. The usage ratio of the polymerization initiator is preferably 0.01 parts by mass to 50 parts by mass, and more preferably 0.1 parts by mass to 40 parts by mass relative to the total of 100 parts by mass of the monomers used in the reaction.

The polymerization reaction of the (meth)acrylic monomer is preferably carried out in an organic solvent. Examples of the organic solvent used in this reaction include alcohols, ethers, ketones, amides, esters, and hydrocarbon compounds. Among these, it is preferable to use at least one selected from the group consisting of alcohols and ethers, and it is more preferable to use partial ethers of polyhydric alcohols. As a preferable specific example, diethylene glycol methyl ethyl ether, propylene glycol monomethyl ether acetate, etc. are mentioned, for example. Furthermore, as the organic solvent, one of these can be used alone or two or more of them can be used in combination.

In the polymerization reaction of the (meth)acrylic monomer, the reaction temperature is preferably 30°C to 120°C, more preferably 60°C to 110°C. The reaction time is preferably 1 hour to 36 hours, more preferably 2 hours to 24 hours. In addition, the amount (a) of the organic solvent used is preferably such that the total amount of the monomers used in the reaction (b) is 0.1% by mass to 50% by mass relative to the total amount (a+b) of the reaction solution. . The reaction solution containing the poly(meth)acrylate can be directly used for the preparation of the liquid crystal alignment agent, or the poly(meth)acrylate contained in the reaction solution can be isolated and used for the preparation of the liquid crystal alignment agent.

Regarding the poly(meth)acrylate, from the viewpoint of making the liquid crystal alignment of the formed liquid crystal alignment film good and ensuring the temporal stability of the liquid crystal alignment, gel permeation chromatography (Gel Permeation Chromatography, GPC) proceed The number average molecular weight (Mn) in terms of polystyrene obtained by the measurement is preferably 250 to 500,000, more preferably 500 to 100,000, and still more preferably 1,000 to 50,000.

From the viewpoint of sufficiently obtaining the coating property improvement effect when using a low-boiling point solvent and obtaining a liquid crystal element 10 with sufficiently high transparency, the content ratio of the poly(meth)acrylate in the liquid crystal alignment agent is preferably relative to The total amount of the polymer components of the liquid crystal alignment agent is 3% by mass to 99% by mass. With regard to the lower limit of the content ratio, it is more preferably 5% by mass or more, still more preferably 20% by mass or more, and particularly preferably 50% by mass or more. In addition, the upper limit of the content of poly(meth)acrylate is more preferably 95% by mass or less when the effect of improving various properties of the polymer different from poly(meth)acrylate is obtained. More preferably, it is 90% by mass or less. In addition, poly(meth)acrylate may be used individually by 1 type, and may be used in combination of 2 or more types.

(Other ingredients)

In terms of obtaining the liquid crystal element 10 with high weather resistance, the liquid crystal alignment agent used in the formation of the liquid crystal alignment film 14 and the liquid crystal alignment film 15 preferably contains a poly(meth)acrylate and is selected from the group consisting of silane compounds and At least one of the group consisting of polysiloxanes. The liquid crystal alignment agent preferably contains polysiloxane in terms of the high effect of improving weather resistance and the possibility of further lowering the post-baking temperature. In addition, in terms of further improving the adhesion to the substrate, the liquid crystal alignment agent preferably contains a silane compound.

(Polysiloxane)

Polysiloxanes can be hydrolyzed, for example, by hydrolyzing silane compounds. Obtained by condensation. As the silane compound, for example, tetramethoxysilane, tetraethoxy Tetraalkoxysilane compounds such as methyl silane; methyl triethoxy silane, phenyl trimethoxy silane, phenyl triethoxy silane, dimethyl diethoxy silane and other alkanes containing alkyl or aryl groups Oxysilane compounds; sulfur-containing alkoxysilane compounds such as 3-mercaptopropyltriethoxysilane and mercaptomethyltriethoxysilane; glycidoxymethyltrimethoxysilane, glycidoxymethyl Triethoxysilane, 2-glycidoxyethyltrimethoxysilane, 2-glycidoxyethyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxysilane Glyceryloxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, etc. containing ring Alkoxysilane compound of oxy group; 3-(meth)acryloyloxypropyl trimethoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-(meth) Group) acryloxypropylmethyl diethoxysilane, vinyl triethoxysilane and other unsaturated bond-containing alkoxysilane compounds; 3-aminopropyltrimethoxysilane, 3-amino group Propyl triethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane Silane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane , N-ethoxycarbonyl-3-aminopropyl trimethoxysilane and other nitrogen-containing alkoxysilane compounds; trimethoxysilylpropyl succinic anhydride and other acid anhydride group-containing alkoxysilane compounds, etc. Hydrolyzable silane compounds can be used alone or in combination of two above. Furthermore, "(meth)acryloyloxy group" means to include "acryloyloxy group" and "methacryloyloxy group".

The hydrolysis. The condensation reaction is performed by reacting one or two or more of the above-mentioned hydrolyzable silane compounds with water, preferably in the presence of a suitable catalyst and organic solvent. During the reaction, the use ratio of water is preferably 1 mol to 30 mol with respect to 1 mol of the hydrolyzable silane compound (total amount). Examples of the catalyst used include acids, alkali metal compounds, organic bases, titanium compounds, zirconium compounds, and the like. The amount of the catalyst used depends on the type of catalyst, temperature and other reaction conditions, and should be appropriately set. For example, relative to the total amount of the silane compound, it is preferably 0.01 times mol to 3 times mol. Examples of the organic solvent used include hydrocarbons, ketones, esters, ethers, alcohols, etc. Among these, it is preferable to use a water-insoluble or poorly water-soluble organic solvent. The use ratio of the organic solvent is preferably 10 parts by mass to 10,000 parts by mass with respect to 100 parts by mass of the total of the silane compounds used in the reaction.

The hydrolysis. The condensation reaction is preferably carried out by heating in an oil bath or the like, for example. At this time, the heating temperature is preferably 130°C or lower, and the heating time is preferably 0.5 to 12 hours. After the reaction is completed, the organic solvent layer separated from the reaction solution is dried with a desiccant as necessary, and then the solvent is removed, thereby obtaining the target polysiloxane. Furthermore, the synthesis method of polysiloxane is not limited to the hydrolysis. The condensation reaction can also be carried out, for example, by a method of reacting a hydrolyzable silane compound in the presence of oxalic acid and alcohol.

The liquid crystal alignment agent may also contain functional groups such as a photo-alignment group or a pretilt angle imparting group (for example, the vertical alignment group shown below) and the like in the side chain Polysiloxane. The functional group-containing polysiloxane can be obtained, for example, by polymerizing at least a part of the raw material with an epoxy group-containing hydrolyzable silane compound to synthesize a side chain having an epoxy group Polysiloxane, in turn, reacts polysiloxane having epoxy group with carboxylic acid having functional group. Alternatively, a method in which a hydrolyzable silane compound having a functional group is used for polymerization in a monomer can also be adopted.

The reaction of epoxy-containing polysiloxane and carboxylic acid is preferably carried out in the presence of a catalyst and an organic solvent. The use ratio of the carboxylic acid is preferably 5 mol% or more, and more preferably 10 mol% to 80 mol% relative to the epoxy groups of the epoxy group-containing polysiloxane. As the catalyst, for example, a compound known as an organic base or a so-called hardening accelerator that promotes the reaction of an epoxy compound can be used. The use ratio of the catalyst is preferably 100 parts by mass or less with respect to 100 parts by mass of epoxy group-containing polysiloxane.

Preferred specific examples of the organic solvent used include 2-butanone, 2-hexanone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, and butyl acetate. The organic solvent is preferably used in such a ratio that the solid content concentration becomes 5 to 50% by mass. The reaction temperature in the reaction is preferably 0°C to 200°C, and the reaction time is preferably 0.1 hour to 50 hours. After the reaction is completed, the organic solvent layer separated from the reaction solution is dried with a desiccant as needed, and then the solvent is removed, thereby obtaining a polysiloxane with functional groups.

Polysiloxane preferably has a group capable of vertically aligning liquid crystal molecules (hereinafter, also referred to as "vertical alignment group"). Specific examples of the vertical alignment group include an alkyl group having 8 to 22 carbon atoms, a fluorine-containing alkyl group having 6 to 18 carbon atoms, and the formula (5) The represented group, and a group having 17 to 51 carbon atoms having a steroid skeleton, and the like. In the case where the liquid crystal alignment agent contains polysiloxane having a vertical alignment group, the light transmittance and light scattering properties of the obtained liquid crystal element can be better and better.

Regarding the polysiloxane, the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC) is preferably 500 to 1,000,000, more preferably 1,000 to 100,000, and still more preferably 1,000 to 50,000.

From the viewpoint of sufficiently improving the weather resistance of the obtained liquid crystal element 10, the content of polysiloxane in the liquid crystal alignment agent is preferably 1% by mass relative to the total amount of the polymer components in the liquid crystal alignment agent. Above, it is more preferable to set it as 2 mass% or more, and it is more preferable to set it as 5 mass% or more. In addition, the upper limit of the content of polysiloxane is preferably set to 97% by mass or less, and more preferably set to 90% by mass or less. Furthermore, polysiloxanes may be used singly or in combination of two or more.

(Silane compound)

The silane compound contained in the liquid crystal alignment agent is an organosilicon compound having a carbon-silicon bond, and specific examples thereof include hydrolyzable silane compounds exemplified as silane compounds used in the synthesis of polysiloxanes. The silane compound preferably has an alkoxysilyl group (-Si(OR) _r R _3-r ) (R is an alkyl group, and r is an integer of 1 to 3. A plurality of Rs may be the same or different from each other)), It is more preferably an alkoxysilane compound having at least one functional group selected from the group consisting of an epoxy group, an amine group, and a thiol group, and particularly preferably an epoxy group-containing alkoxysilane compound.

In the case of blending a silane compound in a liquid crystal alignment agent, the adhesiveness to the substrate and the weather resistance of the liquid crystal element 10 are sufficiently improved from the viewpoint of In other words, the blending ratio of the silane compound is preferably 0.5 parts by mass or more with respect to 100 parts by mass of the total polymer, and more preferably 1 to 30 parts by mass. Furthermore, a silane compound may be used individually by 1 type, and may be used in combination of 2 or more types.

(Polymer with photo-alignment group)

The liquid crystal alignment agent used in the formation of the liquid crystal alignment film 14 and the liquid crystal alignment film 15 preferably contains a polymer having a photo-alignment group. Here, the "photoalignment group" refers to a functional group that imparts anisotropy to the film by a photoisomerization reaction, a photodimerization reaction, a photolysis reaction, and a photofries rearrangement reaction caused by light irradiation . Specific examples of the photoalignment group include, for example, an azobenzene-containing group containing azobenzene or its derivative as the basic skeleton, a cinnamic acid structure-containing group containing cinnamic acid or its derivative as the basic skeleton, A chalcone-containing group containing chalcone or a derivative thereof as a basic skeleton, a benzophenone-containing group containing benzophenone or a derivative thereof as a basic skeleton, a coumarin or a derivative thereof as a basic skeleton The coumarin-containing group of the skeleton, the cyclobutane-containing structure containing cyclobutane or a derivative thereof as the basic skeleton, and the like. Among these, in terms of high sensitivity to light, a group containing a cinnamic acid structure is preferable, and examples thereof include groups having a partial structure represented by the following formula (1).

(In formula (1), R is an alkyl group with 1 to 10 carbons, an alkoxy group with 1 to 10 carbons, A fluorine-containing alkyl group having 1 to 10 carbon atoms in which at least one hydrogen atom is substituted by a fluorine atom, a fluorinated alkoxy group having 1 to 10 carbon atoms or a fluorine atom in which at least one hydrogen atom is substituted by a fluorine atom. a is an integer from 0 to 4. When a is 2 or more, a plurality of Rs may be the same or different. "*" means a bond key)

In the partial structure represented by the formula (1), one of the two bonding bonds "*" is preferably bonded to the group represented by the following formula (4). In this case, it is preferable to improve the light transmittance and light scattering properties of the obtained liquid crystal element.

[Chemistry 4]HR ¹¹ -R ¹² -＊ (4)

(In formula (4), R ¹¹ is phenylene, biphenylene, triphenylene, cyclohexylene, or biscyclohexylene, and it may also have an alkyl group with 1 to 20 carbon atoms in the ring part. An alkoxy group with 1 to 20, a fluorinated alkyl group with 1 to 20 carbons in which at least one hydrogen atom is substituted with a fluorine atom, a fluorinated alkoxy group with 1 to 20 carbons in which at least one hydrogen atom is substituted with a fluorine atom, or Fluorine atom. When R ^{12 is} bonded to the benzene ring in formula (1), it is a single bond, a C1-C3 alkanediyl group, an oxygen atom, a sulfur atom, -CH=CH-, -NH-, -COO- or -OCO-, when bonded to the carbonyl group in formula (1), is a single bond, a C1-C3 alkanediyl group, an oxygen atom, a sulfur atom, or -NH-. "*" means Bonding key)

The photo-alignment group may be possessed by poly(meth)acrylate or may be possessed by a polymer different from poly(meth)acrylate. As the main skeleton of the polymer having a photoalignment group, for example, polyamide acid, polyamide ester, polyimide, Polysiloxane, polyamide, etc. From the viewpoint of ensuring the reliability and weather resistance of the liquid crystal element 10, a polysiloxane having a photo-alignment group can be preferably used.

The method of synthesizing the polymer having a photoalignment group is not particularly limited, as long as it is appropriately selected according to the main skeleton of the polymer. As specific examples, (1) a method of polymerizing a monomer having a photo-alignment group, (2) synthesizing a polymer having a first functional group (for example, epoxy group, etc.) in the side chain, and then making it have A method of reacting a second functional group (for example, a carboxyl group, etc.) with a first functional group, a reactive compound of a photoalignment group, and a polymer having the first functional group, and the like. When the polymer having a photoalignment group is polysiloxane, it is preferable to use the method (2) in terms of high efficiency of introduction of side chains.

In the case where the liquid crystal alignment agent contains a polymer having a photo-aligning group and a polymer not containing the photo-aligning group, from the viewpoint of imparting sufficient alignment ability to the coating film formed using the liquid crystal alignment agent by radiation irradiation In other words, the content of the polymer having a photo-alignment group is preferably 1% by mass or more with respect to the total amount of the polymer components in the liquid crystal alignment agent, and more preferably 5% to 99% by mass.

The polymer component contained in the liquid crystal alignment agent is not limited to the poly(meth)acrylate and polysiloxane, and may include other polymers. As other polymers, for example, polyamide, polyimide, polyamide, polyamide, polyester, cellulose derivatives, polyacetals, polystyrene derivatives, poly(benzene Ethylene-phenylmaleimide) derivatives and the like. As other polymers, these are preferably at least one selected from the group consisting of polyamide and polyamide, and more preferably polyamide.

The blending ratio of the other polymer is preferably 20% by mass or less, more preferably 10% by mass or less, and still more preferably 5% by mass relative to the total amount of polymer components in the liquid crystal alignment agent. the following. In addition, the other polymer may be used singly or in combination of two or more kinds.

(Crosslinking agent)

The liquid crystal alignment agent preferably contains a compound having a crosslinkable group (hereinafter also referred to as a crosslinking agent) as another component. The crosslinkable group is a group that can form a covalent bond between the same or different molecules by light or heat. Examples include (meth)acrylic groups, groups having vinyl groups (alkenyl, vinylphenyl, etc.). Etc.), ethynyl, epoxy (oxiranyl, oxetanyl), carboxyl, (protected) isocyanate, etc. Among these, in terms of high reactivity, a (meth)acryloyl group is particularly preferable. In addition, "(meth)acryloyl group" means an acrylic acid group and a methacryloyl group. The number of crosslinkable groups possessed by the crosslinking agent may be one or multiple. In terms of sufficiently improving the reliability of the liquid crystal element, two or more are preferable, and two to six are more preferable.

Specific examples of the crosslinking agent include, for example, allyl group-containing compounds such as diallyl phthalate; ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, diethyl Glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, pentaerythritol tri(meth)acrylate, di-trimethylolpropane tetra(meth)acrylate, pentaerythritol Tetra(meth)acrylate, trimethylolpropane (meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene glycol Tri(meth)acrylate, polyether(meth)acrylate, ethoxylated bisphenol A bis(formaldehyde) (Meth)acrylic acid esters, tricyclodecane dimethanol di(meth)acrylate, 2-methyl-1,8-octanediol di(meth)acrylate and other (meth)acrylic compounds; maleic acid , Itaconic acid, 1,2,4-benzenetricarboxylic acid, tetracarboxylic acid, cis-1,2,3,4-tetrahydrophthalic acid, ethylene glycol bis1,2,4-benzenetricarboxylic acid, Propylene glycol bis 1,2,4- trimellitic acid, 4,4'-oxydiphthalic acid, 1,2,4- trimellitic anhydride and other carboxylic acids; ethylene glycol diglycidyl ether, polyethylene glycol Diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, 2,2-bis(4 -Hydroxyphenyl) propane diglycidyl ether, trimethylolpropane triglycidyl ether, N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis( N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N-di Epoxy compounds such as glycidyl-benzylamine, N,N-diglycidyl-aminomethylcyclohexane, N,N-diglycidyl-cyclohexylamine, etc.; (Protected) isocyanate compounds in which polyvalent isocyanates such as hexamethylene diisocyanate and diphenylmethylene diisocyanate are protected by a protective group. As a crosslinking agent, among these, a polyfunctional (meth)acrylate compound is preferable.

From the viewpoint of sufficiently obtaining the effect of improving liquid crystal alignment and electrical characteristics, the blending ratio of the crosslinking agent is preferably 0.5 parts by mass or more relative to 100 parts by mass of the polymer component used in the preparation of the liquid crystal alignment agent, and more preferably It is 1 part by mass to 40 parts by mass, and more preferably 5 parts by mass to 30 parts by mass. Furthermore, a crosslinking agent may be used individually by 1 type, and may be used in combination of 2 or more types.

(Antioxidants)

The liquid crystal alignment agent preferably contains an antioxidant (also referred to as a polymerization inhibitor) as other components. Antioxidants have a function of invalidating radicals or peroxides generated by energy such as ultraviolet rays or heat to delay or prohibit polymerization. By containing the antioxidant in the alignment film, the polymerization reaction of the polymerizable compound in the liquid crystal composition present near the surface of the alignment film is suppressed, and the effect of suppressing the decrease in the alignment of the liquid crystal can be obtained, which is preferable in this respect . As specific examples of antioxidants, for example, a compound having an amine structure (preferably a hindered amine structure), a compound having a phenol structure (preferably a hindered phenol structure), and a compound having an alkyl phosphate structure (phosphorus-based Antioxidants), compounds having a thioether structure (sulfur-based antioxidants), mixtures of these (mixed-based antioxidants), and the like.

As preferred examples of antioxidants, compounds having an amine structure include, for example, Adk stab LA-52, LA-57, LA-63, LA-68, LA-72, LA-77, LA-81, LA-82, LA-87, LA-402, LA-502 (the above are manufactured by ADEKA), CHIMASSORB 119, CHIMASSORB 2020, CHIMASSORB CHIMASSORB 944, TINUVIN 622, TINUVIN 123, TINUVIN 144, TINUVIN 765, TINUVIN 770, TINUVIN TINUVIN 111, TINUVIN 783, TINUVIN 791 (the above are made by Japan BASF), etc.; compounds having a phenol structure include, for example: Adk stab) AO-20, Adk stab AO-30, Adk stab AO-40, Adk stab AO-50, Adk stab AO-60, Adk stab AO-80, Adk stab stab) AO-330 (the above are made by ADEKA), IRGANOX 1010, IRGANOX 1035, IRGANOX 1076, IRGANOX ) 1098, IRGANOX 1135, IRGANOX 1330, IRGANOX 1726, IRGANOX 1425, IRGANOX 1520, Yi Lu IRGANOX 245, IRGANOX 259, IRGANOX 3114, IRGANOX 3790, IRGANOX 5057, IRGANOX 565, IRGANOX 295 (the above is made by Japan BASF), etc.; phosphorous antioxidants include, for example: Adk stab PEP-4C, Adk stab ( Adk stab PEP-8, Adk stab PEP-36, HP-10, 2112 (Above are manufactured by ADEKA), IRGAFOS 168, GSY-P101 ( The above is manufactured by Sakai Chemical Industry), IRGAFOS 12, IRGAFOS 126, IRGAFOS 38, IRGAFOS P-EPQ (The above is BASF Japan (Japan BASF), etc.; sulfur-based antioxidants include, for example, Adk stab AO-412, Adk stab AO-503 (the above is ADEKA) (Manufactured), IRGANOX PS 800, IRGANOX PS 802 (the above are made by Japan BASF) Etc.; For example, mixed antioxidants include: Adk stab A-611, Adk stab A-612, Adk stab A-613, Adk stab A-613, Adk stab AO-37, Adk stab AO-15, Adk stab AO-18, 328 (the above are made by ADEKA) , TINUVIN 111, TINUVIN 783, TINUVIN 791 (the above are made by Japan BASF), etc. One of these antioxidants can be used alone or two or more of them can be used in combination.

The content ratio of the antioxidant in the liquid crystal alignment agent is preferably 0.01 parts by mass to 15 parts by mass, more preferably 0.01 parts by mass to 10 parts by mass relative to 100 parts by mass of the polymer component used in the preparation of the liquid crystal alignment agent. Preferably, it is 0.1 parts by mass to 10 parts by mass.

Examples of other components contained in the liquid crystal alignment agent include metal chelate compounds, hardening accelerators, surfactants, fillers, dispersants, photosensitizers, and the like. The blending ratio of these other components can be appropriately selected according to each compound within a range that does not impair the effect of the present disclosure.

(Solvent)

The liquid crystal alignment agent is prepared in the form of a liquid composition in which polymer components and other components used as needed are preferably dissolved in a suitable solvent.

As the organic solvent used, for example, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidone, γ-butanone Lactone, γ-butyrolactone Amine, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, acetic acid Butyl ester, methyl methoxy propionate, ethyl ethoxy propionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-isopropyl ether, ethylene two Alcohol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, two Ethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, diisobutyl ketone, isoamyl propylene Ester, isoamyl isobutyrate, diisoamyl ether, ethylene carbonate, propylene carbonate, etc. These can be used alone or in combination of two or more.

Regarding the organic solvent used in the preparation of the liquid crystal alignment agent, in order to obtain a liquid crystal alignment film that exhibits good element characteristics even when the post-baking temperature is low (for example, when the temperature is set to below 160° C.), these With respect to the total amount of the solvent, it is preferable to include 40% by mass or more of the compound having a boiling point of 160° C. or less under 1 atmosphere, more preferably 50% by mass or more, and even more preferably 70% by mass or more.

The solid content concentration in the liquid crystal alignment agent (the ratio of the total mass of components other than the solvent of the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) is appropriately selected in consideration of viscosity, volatility, etc., preferably 1 mass% to 10 mass % Of the range. When the solid content concentration is less than 1% by mass, the film thickness of the coating film becomes too small, and it is difficult to obtain a good liquid crystal alignment film. On the other hand, when the solid content concentration exceeds 10% by mass, the film thickness of the coating film becomes too large and it is difficult to obtain a good liquid crystal alignment film. In addition, the viscosity of the liquid crystal alignment agent increases and the coatability tends to decrease. .

<Method of Manufacturing Liquid Crystal Element>

Next, a method of manufacturing the liquid crystal element 10 will be described. The liquid crystal element 10 is preferably manufactured by a method including: coating a liquid crystal alignment agent on the respective electrode arrangement surfaces of the first substrate 11 and the second substrate 12 to form a liquid crystal alignment film 14 and a liquid crystal alignment Step A of the film 15; Step B of constructing a liquid crystal cell by arranging a pair of substrates having the liquid crystal alignment film 14 and the liquid crystal alignment film 15 through the layers of the liquid crystal composition such that the electrode arrangement faces each other; and Step C of curing the polymerizable compound after the construction of the liquid crystal cell.

(Step A)

The liquid crystal alignment agent is applied on the respective electrode arrangement surfaces of the first substrate 11 and the second substrate 12, for example, by lithography, spin coating, roll coater, inkjet printing, and bar coater. It is performed by a well-known coating method such as a flexographic printing method and a flexographic printing method. After the liquid crystal alignment agent is applied, for the purpose of preventing dripping of the applied liquid crystal alignment agent, etc., it is preferable to perform preheating (prebaking). The pre-baking temperature is set according to the type of substrate, and is preferably 140°C or lower, more preferably 120°C or lower, and still more preferably 100°C or lower. The lower limit of the pre-baking temperature is preferably 30°C or higher, and more preferably 40°C or higher. The pre-baking time is preferably 0.25 minutes to 10 minutes.

After that, it is preferable to perform a calcination (post-baking) step for the purpose of completely removing the solvent and promoting the crosslinking reaction as necessary. In the case of using a substrate containing a polymer material, the firing temperature (post-baking temperature) at this time is preferably set to 160°C or less, more preferably 150°C or less, and particularly preferably 110°C or less . By setting at least a part of the polymer component of the liquid crystal alignment agent as poly(meth)acrylate, the solubility in low-boiling point solvents can be improved, so that the post-baking temperature can be lowered. Obtaining a homogeneous alignment film can ensure the liquid crystal alignment and voltage retention of the liquid crystal element 10. The post-baking time is preferably 5 minutes to 200 minutes, more preferably 10 minutes to 120 minutes.

(Optical alignment processing)

It is preferable to impart the liquid crystal alignment ability by subjecting a coating film formed using a liquid crystal alignment agent to a rubbing treatment, a photo-alignment treatment, or the like. In this embodiment, a photo-alignment process for imparting liquid crystal alignment ability by light irradiation is performed.

In the photo-alignment process, for the light irradiation of the coating film, for example, radiation rays such as ultraviolet rays and visible rays including light with a wavelength of 150 nm to 800 nm can be used. The radiation may be polarized light or non-polarized light, or a combination of these may be irradiated. The exposure method is not particularly limited, and examples thereof include a method of irradiating linearly polarized light from a direction perpendicular to the substrate surface or an oblique direction, and a method of irradiating non-polarized light from an oblique direction.

As the light source used, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, etc. can be used. Ultraviolet rays in a preferable wavelength range can be obtained as a light source by a mechanism used in combination with a filter, a diffraction grating, and the like. The radiation dose is preferably 10 J/m ² to 50,000 J/m ² , and more preferably 20 J/m ² to 10,000 J/m ² . The light irradiation used for the photo-alignment treatment can be performed by the following method, etc., which is a method of irradiating the coating film after the post-baking step, and performing the coating film after the pre-baking step and before the post-baking step. The irradiation method, the method of irradiating the coating film during the heating process in any one of the pre-baking step and the post-baking step.

(Step B)

In step B, two substrates with a liquid crystal alignment film are prepared, and a layer of a liquid crystal composition containing a liquid crystal and a polymerizable compound is arranged between the two substrates facing each other such that the liquid crystal alignment film faces to produce a liquid crystal cell. Specifically, it can be exemplified by bonding the peripheral portions of the first base material 11 and the second base material 12 with a sealant, and injecting and filling the liquid crystal composition into the cell gap partitioned by the surface of the base material and the sealant. A method of sealing the injection hole; a sealant is applied to the periphery of the liquid crystal alignment film side of one of the substrates, and then the liquid crystal composition is dropped on a predetermined number of places on the liquid crystal alignment film surface, and then the liquid crystal alignment film is opposed The method of laminating another substrate and spreading the liquid crystal on the entire surface of the substrate, and then hardening the sealant (One Drop Filling (ODF) method), etc. As the sealing agent, for example, an epoxy resin containing a curing agent and alumina balls as spacers can be used.

(Step C)

In step C, a treatment of hardening the liquid crystal composition by performing one or more treatments selected from heating and light irradiation is performed. The heating temperature during the curing reaction can be appropriately selected according to the type of polymerizable compound and liquid crystal used, for example, heating is performed at a temperature in the range of 40°C to 80°C. The heating time is preferably 0.5 minutes to 5 minutes. In the case of curing by light irradiation, as the irradiation light, non-polarized ultraviolet rays having a wavelength in the range of 200 nm to 500 nm can be preferably used. The amount of light irradiation is preferably 50 mJ/cm ² to 10,000 mJ/cm ² , and more preferably 100 mJ/cm ² to 5,000 mJ/cm ² .

The liquid crystal element 10 can be used in various applications, for example, it can be effectively used as windows in buildings, partition walls (partitions) between indoor and outdoor, shop windows, vehicles (cars, airplanes, Ships, railways, etc.) windows, various indoor and outdoor advertisements, guide signs, home appliances, mobile phones, smartphones, various monitors, clocks, portable game consoles, computers, glasses, sunglasses, medical equipment, furniture, etc. Of various dimming components. The liquid crystal element 10 can be used as it is depending on the thickness, hardness, shape, use, etc. of the element, and it can also be used by bonding to glass, transparent resin, or the like.

(Liquid crystal device)

The display device of the present disclosure includes: the liquid crystal element; and a transparent display that is transparent in a non-display state. Specifically, as shown in FIG. 3, the display device 20 has a structure in which the liquid crystal element 10 is arranged on the back surface of the transparent display 30. When the liquid crystal element 10 functions as a dimming element, the visibility of the display of the transparent display 30 changes.

The transparent display 30 is, for example, an organic electroluminescence element (organic EL element), and includes: a pair of glass substrates; an anode electrode and a cathode electrode formed of a transparent electrode material; and a hole transport layer formed between the anode electrode and the cathode electrode And luminescent layer. The transparent display 30 is transparent in its entire surface in a non-display state where no voltage is applied. By applying a voltage, the pixels applied with the voltage emit light to display characters, images, and the like.

In the display device 20 of FIG. 3, the entire surface of the display device 20 is transparent when the liquid crystal element 10 and the transparent display 30 are not applied with voltage. Therefore, for example, when the display device 20 is applied as a front glass or a rear glass of a shop window, the appearance of the products displayed on the counter or the shop can be seen from outside the house. In addition, with the liquid crystal element 10 in a state where no voltage is applied, electricity is applied to the transparent display 30. By pressing, the characters, images, etc. displayed on the transparent display 30 are displayed in a state of floating on the glass.

On the other hand, in a state where a voltage is applied to the liquid crystal element 10, the back surface of the transparent display 30 is shielded from light. In this case, the characters, images, etc. displayed on the display device 20 can be prevented from overlapping with objects behind the display device 20, and the display of the transparent display 30 can be easily observed. In addition, the decoration can also be improved. Alternatively, a configuration may be adopted in which the applied voltage of the liquid crystal element 10 is controlled according to the brightness of the front or back of the display device 20, thereby changing the degree of light transmission from the front to the back of the display device 20.

Furthermore, in the display device 20 of FIG. 3, it is also possible to adopt a configuration in which the dimming element 10 is arranged only in a part of the transparent display 30. Alternatively, a configuration may be adopted in which the display area of the transparent display 30 is divided into a plurality and the dimming element is arranged according to the display area, so that the transmittance can be changed according to the display area.

In the above-mentioned embodiment, the liquid crystal alignment film 14 and the liquid crystal alignment film 15 are used as photo-alignment films, but they may also be those that do not perform photo-alignment treatment. In this case, when a substrate containing a polymer material is used as the substrate of the liquid crystal element 10, the following liquid crystal element can also be obtained, that is, the liquid crystal alignment film is homogeneous, the liquid crystal alignment film has high transparency and light transmission characteristics And it has good light scattering properties, shows sufficient electrical properties and excellent weather resistance on the basis of realizing the dimming function.

[Example]

Hereinafter, the content of the present disclosure will be further described in detail through embodiments, but the content of the present disclosure is not limited to these embodiments.

In the following examples, the weight average molecular weight Mw, number average molecular weight Mn, and epoxy equivalent of the polymer, and the solution viscosity of the polymer solution are measured by the following methods. The necessary amounts of the raw material compounds and polymers used in the following examples are ensured by repeating the synthesis at the synthesis scale shown in the following synthesis examples as necessary.

[The weight average molecular weight Mw and the number average molecular weight Mn of the polymer]

Mw and Mn are polystyrene conversion values obtained by GPC measurement under the following conditions.

Column: manufactured by Tosoh Co., Ltd., TSKgelGRCXLII

Solvent: Tetrahydrofuran

Temperature: 40℃

Pressure: 68kgf/cm ²

[Epoxy equivalent]

The epoxy unit weight is measured by the hydrochloric acid-methyl ethyl ketone method described in Japanese Industrial Standards (JIS) C2105.

[Solution viscosity of polymer solution]

The solution viscosity (mPa·s) of the polymer solution was measured at 25°C using an E-type rotary viscometer.

The relationship between the abbreviations and structural formulas of the compounds used in the following examples is as follows. In the following, for convenience, the "compound represented by formula (X)" is simply expressed as "compound (X)".

(carboxylic acid)

(Polymerizable compound)

(Photoinitiator)

[化7]

(Crosslinking agent)

(Silane compound)

(Antioxidants)

[化10]

(Dichroic pigment)

<Synthesis of poly(meth)acrylate>

[Synthesis Example 1]

In a flask equipped with a cooling pipe and a stirrer, 1.2 parts by mass of 2,2'-azobisisobutyronitrile and 200 parts by mass of propylene glycol monomethyl ether acetate were charged. Then, 80 parts by mass of glycidyl methacrylate and 20 parts by mass of styrene were charged, and after nitrogen replacement, stirring was gradually started. After raising the temperature of the solution to 95°C, the temperature was maintained for 5 hours to obtain a polymer solution containing a polymer (Pac-1). In addition, the monomer consumption after the reaction is calculated based on the measurement result of the solid content concentration of the polymer solution The rate is 99%.

[Synthesis Example 2]

In a flask equipped with a cooling pipe and a stirrer, 1.2 parts by mass of 2,2'-azobisisobutyronitrile and 200 parts by mass of propylene glycol monomethyl ether acetate were charged. Then, 50 parts by mass of glycidyl methacrylate and 50 parts by mass of tricyclo[5.2.1.0 ^2.6 ]dec-8-yl=methacrylate were charged, and after nitrogen replacement, stirring was slowly started. After raising the temperature of the solution to 95°C, the temperature was maintained for 5 hours to obtain a polymer solution containing a polymer (Pac-2). In addition, the monomer consumption rate after the completion of the reaction calculated from the measurement result of the solid content concentration of the polymer solution was 99%.

<Synthesis of Polysiloxane with Epoxy Group>

[Synthesis Example 3]

A reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a reflux cooling tube is charged with 100.0 g of 2-(3,4-epoxycyclohexyl) ethyl trimethoxysilane (ECETS) and methyl isobutyl ketone 500g and 10.0g of triethylamine were mixed at room temperature. Then, after adding 100 g of deionized water dropwise for 30 minutes from the dropping funnel, the mixture was mixed under reflux and reacted at 80°C for 6 hours. After the reaction, the organic layer was taken out and washed with a 0.2% by mass ammonium nitrate aqueous solution until the washed water became neutral, and then the solvent and water were distilled off under reduced pressure to obtain polysilicon with epoxy groups. Oxyane acts as a viscous transparent liquid. ¹ H-nuclear magnetic resonance (NMR) analysis was performed on the epoxy-containing polysiloxane, and the results confirmed that an epoxy-based peak can be obtained near the chemical shift (δ)=3.2ppm , The reaction process will not cause side reactions of epoxy groups. The weight average molecular weight (Mw) of the epoxy-containing polysiloxane (SEp-1) obtained in Synthesis Example 3 was Mw=2,200, and the epoxy equivalent was 186 g/mole.

<Synthesis of polysiloxane with functional groups>

[Synthesis Example 4]

A 100 mL three-necked flask was charged with 18.4 g of epoxy-containing polysiloxane (SEp-1) obtained in Synthesis Example 3, 70.8 g of methyl isobutyl ketone, and 3.45 of cinnamic acid derivative (CA-1). g (15 mol parts relative to 100 mol parts of epoxy groups of polyorganosiloxane (SEp-1)), cinnamic acid derivative (CA-2) 6.21g (relative to polysiloxane (SEp-1) the epoxy group which has 100 mol parts and 25 mol parts) and 1.03 g of tetrabutylammonium bromide were stirred at 80°C for 12 hours. After the completion of the reaction, 40 g of diethylene glycol diethyl ether and 60 g of cyclohexane were added. After washing the solution with 6 times of liquid separation and washing, 100 g of diethylene glycol diethyl ether was added to make the solid content concentration 10 The solvent is distilled off by mass%. Thereby, a diethylene glycol diethyl ether solution containing a polymer (S-1) of polysiloxane having a functional group with a solid content concentration of 10% by mass was obtained. The weight average molecular weight Mw of the polymer (S-1) was 17,000.

[Synthesis Example 5 and Synthesis Example 6]

The type and amount of carboxylic acid used in the reaction were changed as described in Table 1 below, except that it was synthesized in the same manner as in Synthesis Example 4 to obtain polymer (S-2) and polymer (S-3) as having Functional base polysiloxane. In addition, the number in Table 1 shows the molar part with respect to 100 molar parts of epoxy groups which polysiloxane (SEp-1) has.

[Table 1]

<Synthesis of polyamide acid>

[Synthesis Example 7]

121.35 g of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride (90 mol parts relative to 100 mol parts of the total amount of diamine used in the synthesis), and as Diamine compound of 3,5-diaminobenzoic acid cholesteryl ester 94.34g (relative to the total amount of diamine used in the synthesis of 100 mol parts and 30 mol parts) and 4,4'-two 84.3 g of amino diphenyl ether (70 mol parts relative to 100 mol parts of the total amount of diamine used in the synthesis) was dissolved in N-methyl-2-pyrrolidone (N-Methyl-2- In 1200 g of pyrrolidone, NMP, the reaction was carried out at 30°C for 6 hours. Then, the reaction mixture was poured into a large amount of excess methanol to precipitate the reaction product. After washing the collected precipitate with methanol, it was dried at 40°C under reduced pressure for 15 hours to obtain 290 g of polyamide acid (hereinafter referred to as polymer (PA-1)). The resulting polymer (PA-1) was prepared in a manner of 20% by mass in NMP, and the viscosity of the solution was measured, and the result was 1310mPa. s. In addition, the polymer solution was allowed to stand at 20°C for 3 days. As a result, gelation did not occur and the storage stability was good.

<Synthesis of Polyimide>

[Synthesis Example 8]

3.19 g (12.8 mmol) of 2,4,6,8-tetracarboxylic bicyclo[3.3.0]octane-2:4,6:8-dianhydride as tetracarboxylic dianhydride and diamine compound 1,3-diamino-4-[4-(trans-4-n-pentylcyclohexyl)phenoxymethyl]benzene 4.59g (11.6mmol) and 3,5-diaminobenzoic acid 2.16g( 14.2mmol) was dissolved in 24.9g of NMP, and after reacting at 80°C for 5 hours, 2.50g (12.8mmol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride was added as tetracarboxylic dianhydride And 12.4 g of NMP, and reacted at 40°C for 8 hours to obtain a polyamide acid solution with a polymer concentration of 25% by mass. After adding NMP to 30.0 g of the obtained polyamide acid solution and diluting to 6 mass %, 3.95 g of acetic anhydride and 2.40 g of pyridine were added, and the reaction was carried out at 50° C. for 2 hours. Then, the reaction mixture was poured into a large amount of excess methanol to precipitate the reaction product. After washing the collected precipitate with methanol, it was dried at 100°C under reduced pressure to obtain polyimide (hereinafter referred to as polymer (PI-1)). The obtained polyimide had an imidization rate of 55% and a weight average molecular weight of 48,000.

<Preparation of Liquid Crystal Composition>

1. Preparation of liquid crystal composition I

Liquid crystal (MLC-6608, manufactured by Merck (Merck)) 1.20 g, compound (R-1) 1.20 g, compound (R-2) 0.60 g, compound (R-3) 0.12 g and 0.36 g of the compound (R-4) and 0.012 g of the compound (P-1) as a photoinitiator were mixed, and the mixture was heated and cooled to 25° C. to obtain a liquid crystal composition I.

2. Preparation of liquid crystal composition II

1.20 g of liquid crystal (MLC-6608, manufactured by Merck), 0.024 g of the dichroic dye shown below, 1.20 g of compound (R-1) as a polymerizable compound, compound (R-2) 0.60 g, 0.12 g of compound (R-3), 0.36 g of compound (R-4), and 0.012 g of compound (P-1) as a photoinitiator were mixed, and heated and cooled to 25°C to obtain a liquid crystal composition II.

(Dichroic pigment)

A mixture of 6.0 parts by mass of compound (m-1), 2.0 parts by mass of compound (m-2), and 2.0 parts by mass of compound (m-3) was used.

[Example 1]

<Preparation of Liquid Crystal Alignment Agent>

As a polymer component, the diethylene glycol diethyl ether solution containing polymer (S-1) obtained in Synthesis Example 4 was converted into polymer (S-1), and an amount equivalent to 20 parts by mass, and a synthesis example The solution containing the polymer (PAc-1) obtained in 1 is mixed in an amount equivalent to 80 parts by mass of the polymer (PAc-1) and 5 parts by mass of the compound (add-2), and added as a solvent Propylene Glycol Monomethyl Ether (PGME), Diethylene Glycol Diethyl Ether (DGDE), Propylene Glycol Monomethyl Ether Acetate (PGMEA), with solid content concentration It was prepared so that the weight ratio of each solvent was 4% by mass and the weight ratio of each solvent was PGME:DGDE:PGMEA=30:20:50. Then, the resulting solution was filtered with a filter having a pore size of 0.2 μm, thereby preparing a liquid crystal alignment agent (A-1).

<Evaluation of Liquid Crystal Alignment Agent and Liquid Crystal Element>

1. Evaluation of applicability

Use a bar coater to coat the prepared liquid crystal alignment agent (A-1) on a polyethylene terephthalate (PET) film substrate (PET-ITO base) with an ITO electrode on the surface of the substrate. The electrode arrangement surface of the material) is pre-baked on a hot plate at 80°C for 1 minute, and then heated (post-baked) in an oven at 120°C in which nitrogen is replaced in the library for 2 minutes to form an average A coating film with a thickness of 0.1 μm. The coating film was observed visually and with a microscope with a magnification of 100 times, and the presence of uneven film thickness, uneven coating, and pinholes was checked. The evaluation was performed in the following manner, that is, the case where film thickness unevenness, uneven coating, and pinholes were not observed even with visual observation and 100-fold microscopic observation was regarded as the coatability "good", and 100 If the pinholes are observed with a microscope but the uneven coating on the surface of the coating film is not observed by visual inspection, it is regarded as the coatability "pass." The case of at least any one of the holes is referred to as "bad" coating properties. In this example, neither film thickness unevenness, uneven coating, and pinholes were observed by visual observation and a microscope at 100 times, and the coatability was "good".

2. Evaluation of the transparency of the coating film

For the coating film obtained in 1. above, using a spectrophotometer (150-20 type dual electron beam manufactured by Hitachi, Ltd.), the transparency of the coating film was evaluated by the light transmittance (%) at a wavelength of 400 nm sex. In the evaluation, the case where the light transmittance is 97% or higher is regarded as the transparency "good", and the case where the light transmittance is less than 97% is regarded as the transparency "bad". As a result, the light transmittance of the coating film was 98.1%, and the transparency was "good".

3. Manufacturing of liquid crystal elements

For the surface of the coating film produced in 1., use a Hg-Xe lamp and a Glan-Taylor prism, and irradiate a polarized ultraviolet 20mJ/cm ² containing a bright line of 313nm from the normal line of the substrate at an angle of 20° from the normal line of the substrate to obtain the liquid crystal alignment membrane. Repeat the same operation to prepare a pair (two pieces) of substrates with liquid crystal alignment films. Then, a 6 μm spacer was coated on the surface of one of the substrates with the liquid crystal alignment film, and then the prepared liquid crystal composition I was dropped on the surface of the liquid crystal alignment film coated with the spacer. Then, the two substrates were bonded with the sealant so that the liquid crystal alignment film faces of the other substrate faced each other to obtain a liquid crystal cell. Using an ultraviolet irradiation device that uses an ultraviolet light-emitting diode as a light source, ^{the liquid crystal cell is irradiated with ultraviolet rays under the conditions of a wavelength of 365nm, an ultraviolet intensity of 15mW/cm 2} , an irradiation time of 15 seconds, and a substrate surface temperature of 20°C to make the liquid crystal composition The substance I is cured, so that the liquid crystal element 10 shown in FIG. 1 is obtained.

4. Evaluation of light transmittance

The transparency at the time of no voltage application was evaluated by measuring the haze (HAZE) of the liquid crystal element in a state where no voltage was applied. The measurement was performed using a spectroscopic haze meter (manufactured by Tokyo Denshoku Co., Ltd.). The lower the haze value, the better the transparency. As a result, in this example, the haze value=2%, and the transparency in the state where no voltage is applied is excellent.

5. Evaluation of light scattering

By measuring the haze (HAZE) of the liquid crystal element in the voltage application state, the light scattering property at the time of voltage application was evaluated. The measurement was performed by applying 20 V to the liquid crystal element manufactured in the above 3. by AC drive, and performed using a spectroscopic haze meter (manufactured by Tokyo Denshoku Co., Ltd.) in the same manner as in the above 4. The higher the haze value, the better the light scattering properties. That As a result, in this example, the haze value=92%, and the light scattering property in the voltage applied state was excellent.

6. Evaluation of voltage holding rate

For the liquid crystal element manufactured in 3., after applying a voltage of 5V at 23°C with an application time of 60 microseconds and a span of 167 milliseconds, the voltage holding ratio (VHR _BF ) after 1670 milliseconds from the release of the application was measured , The resulting voltage retention rate is 80.4%. In addition, VHR-1 manufactured by Toyo Technology Co., Ltd. was used as the measuring device.

7. Evaluation of weather resistance

Using a light resistance tester (SUNTEST CPS+: manufactured by Toyo Seiki Co., Ltd.), the liquid crystal element manufactured in 3. was irradiated with xenon light (illuminance 250W/m ² (300nm-800nm) for 200 hours) ). Regarding the liquid crystal element after light irradiation, the voltage holding ratio was measured by the same method as in 6. above. The value was set as the voltage retention rate after light irradiation (VHR _AFXe ). _{The reduction rate ΔVHR Xe} (%) of the voltage holding ratio was obtained from the following formula (EX-1), and the weather resistance was evaluated based on the reduction rate ΔVHR _Xe.

△VHR _Xe =((VHR _BF -VHR _AFXe )÷VHR _BF )×100…(EX-1)

If △VHR _{Xe is} less than 5%, it is judged as “good” weather resistance, if it is over 5% and less than 10%, it is judged as “pass”, and if it is over 10%, it is judged as “bad”. _{As a result, the ΔVHR Xe} of the liquid crystal element of this example was 3.5%, and the weather resistance was "good".

In addition, regarding the liquid crystal element after 200 hours of light irradiation, The above 4. The same method is used to measure the haze value in a state where no voltage is applied, and the weather resistance is evaluated based on the haze value. As a result, in the liquid crystal element of this example, the haze value was also 2% after light irradiation, and the transparency did not change before and after light irradiation.

[Example 2 to Example 7 and Comparative Example 1]

Except for using the types and blending amounts of each component shown in Table 2 below, the same operation as the preparation of the liquid crystal alignment agent (A-1) was carried out to prepare each liquid crystal alignment agent (A-2) to the liquid crystal alignment agent (A -8). In addition, using each liquid crystal alignment agent (A-2) to a liquid crystal alignment agent (A-8), the liquid crystal element was evaluated in the same manner as in Example 1. The results are shown in Table 3 below.

[Example 8]

1. Manufacture and evaluation of liquid crystal elements

Except that liquid crystal composition II was used instead of liquid crystal composition I, a liquid crystal element was manufactured in the same manner as in Example 1. In addition, the same evaluation as in Example 1 was performed using the obtained liquid crystal cell. The results are shown in Table 3 below.

In Example 8, using the liquid crystal element manufactured in 1. above, the following evaluations (evaluation of light transmittance, evaluation of light blocking properties, and evaluation of repeated drive durability test) were further performed.

2. Evaluation of light transmittance

The transparency when no voltage was applied was evaluated by measuring the transmittance of the liquid crystal element in a state where no voltage was applied. The measurement was performed using a spectrophotometer (150-20 type dual electron beam manufactured by Hitachi, Ltd.), and the light transmittance was evaluated by the light transmittance (%) at a wavelength of 400 nm. The higher the transmittance value, the better the transparency. As a result, the reality In the example, the transmittance=93%, and the transparency in the state where no voltage is applied is excellent.

3. Evaluation of light blocking properties

By measuring the transmittance of the liquid crystal element in the voltage application state, the light shielding property at the time of voltage application was evaluated. The measurement was performed by applying 40 V to the liquid crystal element manufactured in 1. above by AC drive, and using a spectrophotometer (150-20 type dual electron beam manufactured by Hitachi, Ltd.) in the same manner as in 2. The lower the transmittance value, the better the light shielding property. As a result, in this example, the transmittance=5%, and the light shielding property in the voltage applied state was excellent.

4. Evaluation of repeated drive durability test

A voltage of 40 V was applied to the liquid crystal element for 1 second, and thereafter, it was left in a state where it was not applied for 1 second. After the operation was repeated 1800 times, the light transmittance and the light shielding property were evaluated in the same manner as in the above 2. and the above 3. to perform the evaluation of the repeated driving endurance test. As a result, in this example, the transmittance when no voltage is applied=93%, and the transmittance when voltage is applied=7%. Before and after driving, no change in transmittance is observed when no voltage is applied. The increase in transmittance is only 2%. From this result, it can be said that the liquid crystal element of this example is excellent in the durability of repeated driving.

The numerical value of the compounding amount in Table 2 represents the compounding ratio (parts by mass) of each compound to 100 parts by mass in total of the polymer components used in the preparation of the liquid crystal alignment agent.

In Table 2, the abbreviations are as follows.

PGME: Propylene Glycol Monomethyl Ether

PGMEA: Propylene Glycol Monomethyl Ether Acetate

DGDE: Diethylene glycol diethyl ether

NMP: N-methyl-2-pyrrolidone

GBL: γ-butyrolactone

According to Table 3, it can be seen that the liquid crystal alignment film containing poly(meth)acrylate is homogeneous and has high transparency even when the post-baking temperature is set to a low temperature (120°C). In addition, the light transmission characteristics of the liquid crystal element and Good light scattering properties. In addition to this, the voltage retention rate of the obtained liquid crystal element was also sufficiently high, and the weather resistance was also good. In particular, the coating properties, light transmittance, and light scattering properties of Examples 1 and 2 in which poly(meth)acrylate and polysiloxane are contained in the liquid crystal alignment film and the ratio of poly(meth)acrylate is high , Electrical properties and weather resistance are particularly excellent. In addition, regarding Example 7 in which an antioxidant is contained in the liquid crystal alignment film, in the obtained liquid crystal element, the haze value when no voltage is applied or the haze value after weather resistance evaluation is different from the fact that the liquid crystal alignment film does not contain an antioxidant. Compared with Example 4, it is excellent.

In addition, in Example 8 in which the dye (dichroic dye) was dispersed in the liquid crystal layer, the voltage retention of the obtained liquid crystal element was sufficiently high, and the weather resistance was also good. In addition, even after repeated voltage application/non-application to the liquid crystal element, both light shielding properties and light transmittance were good, and the driving durability was excellent. It is considered that the state is caused by the assistance of the alignment film side.

In contrast, in Comparative Example 1, which is a liquid crystal alignment film containing polyimide, the coatability and transmittance of the coating film and the light transmittance and weather resistance (haze value) of the liquid crystal element are inferior to those of the Examples.

<Display test when combined with a transparent display>

[Example 9]

A display device in which the liquid crystal element manufactured in Example 2 was superimposed on one outer surface of a transparent display was performed, and the display of the transparent display was performed. As a result, it was judged that the transparency of the liquid crystal element was good in the state of no voltage applied, and the visibility of the display of the transparent display Sex is "good".

[Comparative Example 2]

The display test was performed in the same manner as in Example 9, except that a polarizing plate-based liquid crystal element was used instead of the liquid crystal element of Example 9. As the liquid crystal element of the polarizing plate method, the following is used: a transparent electrode and a liquid crystal alignment film are respectively formed on the opposing surfaces of a pair of glass substrates, liquid crystal is filled between the pair of substrates, and a sealant is arranged on the periphery The polarizing plate is arranged outside the glass substrate of the liquid crystal cell. As a result, in Comparative Example 2, the light transmittance of the liquid crystal element was poor, and it was determined that the visibility of the transparent display was "bad". In this case, it can be said that the light transmittance of the PDLC element using acrylic resin is good. On the other hand, in the liquid crystal element of the polarizing plate type, since light absorption in the polarizing plate exists, the transmittance does not theoretically become 50% or more, and the visibility of the transparent display deteriorates. From the above, it can be said that as a display element superimposed on a transparent display, the liquid crystal element 10 having a liquid crystal alignment film containing poly(meth)acrylate is particularly excellent.

This disclosure is described in accordance with the embodiment, but it can be understood that the disclosure is not limited to the embodiment or structure. The present disclosure also includes various modifications or modifications within an equal range. In addition, various combinations or forms, and further in these Other combinations or forms that include only one element, more than one element, or less than one element are also included in the scope or scope of the present disclosure.

10‧‧‧Liquid crystal element

11‧‧‧The first base material

12‧‧‧Second base material

13‧‧‧Liquid crystal layer

13a‧‧‧Polymer

13b‧‧‧Liquid crystal molecules

14,15‧‧‧LCD alignment film

16,17‧‧‧Transparent electrode

Claims (14)

A liquid crystal element, comprising: a pair of substrates arranged in opposite directions; electrodes, respectively arranged on the surfaces of the pair of substrates facing each other; a liquid crystal layer, arranged between the pair of substrates, and A liquid crystal composition containing a liquid crystal and a polymerizable compound is formed by curing; and a liquid crystal alignment film is formed on the electrode arrangement surface of at least one of the pair of base materials; the liquid crystal composition contains monofunctional (meth)acrylic acid An ester compound, a multifunctional (meth)acrylate compound, a multifunctional thiol compound, and a styrenic compound are used as the polymerizable compound; the liquid crystal alignment film is formed of a liquid crystal alignment agent containing poly(meth)acrylate The liquid crystal layer is a polymer dispersion type liquid crystal layer formed by mixing a polymer obtained by polymerization of the polymerizable compound and the liquid crystal in the layer, the liquid crystal element does not have a polarizing plate, and the liquid crystal element When a voltage is not applied between the electrodes, it becomes a light-transmitting and transparent state; when a voltage is applied between the electrodes, it becomes a non-transparent state where light is scattered. The liquid crystal element according to claim 1, wherein the content ratio of the poly(meth)acrylate in the liquid crystal alignment agent is relative to the total amount of the polymer components contained in the liquid crystal alignment agent 3% by mass to 99% by mass. According to the liquid crystal element described in item 1 or item 2 of the scope of patent application, the liquid crystal alignment agent further contains polysiloxane. The liquid crystal element according to item 1 or item 2 of the scope of patent application, wherein the liquid crystal alignment agent contains a polymer having a photo-alignment group. According to the liquid crystal element described in item 1 or item 2 of the scope of patent application, the liquid crystal alignment agent further contains a silane compound. In the liquid crystal element described in item 1 or item 2 of the scope of patent application, the liquid crystal alignment agent further contains a compound having a crosslinkable group. The liquid crystal element according to the first or second patent application, wherein the liquid crystal composition further contains a dye. The liquid crystal element according to the seventh item of the scope of patent application, wherein the dye is at least one selected from the group consisting of azo compounds and anthraquinone compounds. The liquid crystal element described in item 1 or item 2 of the scope of patent application, wherein the liquid crystal composition further contains an antioxidant. A display device, comprising: a liquid crystal element according to any one of items 1 to 9 of the scope of patent application; and a transparent display that is transparent in a non-display state. A liquid crystal alignment agent is used to form a liquid crystal alignment film of a liquid crystal element. The liquid crystal element is provided between a pair of substrates arranged in such a way that electrodes provided on each substrate surface face each other. The liquid crystal composition is hardened and shaped The liquid crystal layer is formed, and the liquid crystal alignment agent contains a poly(meth)acrylate, and the liquid crystal composition contains a monofunctional (meth)acrylate compound, a multifunctional (meth)acrylate compound, and a multifunctional thiol Compound and styrene-based compound as the polymerizable compound; the liquid crystal layer is a polymer dispersed liquid crystal layer formed by mixing a polymer obtained by polymerizing the polymerizable compound and the liquid crystal in the layer, so The liquid crystal element does not have a polarizing plate, and the liquid crystal element becomes a light-transmitting and transparent state when no voltage is applied between the electrodes; when a voltage is applied between the electrodes, the liquid crystal element becomes a state where light is scattered Non-transparent state. A method for manufacturing a liquid crystal element, the liquid crystal element is provided with a liquid crystal formed by curing a liquid crystal composition containing a liquid crystal and a polymerizable compound between a pair of substrates arranged in such a way that electrodes provided on each substrate surface face each other The method for manufacturing the liquid crystal element includes: coating a liquid crystal alignment agent on the electrode arrangement surface of at least one of the pair of substrates to form a liquid crystal alignment film; after forming the liquid crystal alignment film , The step of constructing a liquid crystal cell by arranging the pair of substrates through a layer containing the liquid crystal composition in such a manner that the electrodes face each other; and hardening the polymerizable compound after constructing the liquid crystal cell Step; The liquid crystal composition contains a monofunctional (meth)acrylate compound, a multifunctional (meth)acrylate compound, a multifunctional thiol compound, and a styrenic compound as The polymerizable compound; the liquid crystal alignment agent contains poly(meth)acrylate, and the liquid crystal layer is a layer made of a polymer polymerized by the polymerizable compound and the liquid crystal mixed together. A molecule-dispersed liquid crystal layer, the liquid crystal element is not equipped with a polarizing plate, the liquid crystal element is in a light-transmitting and transparent state when no voltage is applied between the electrodes; in a state where a voltage is applied between the electrodes Next, it becomes a non-transparent state in which light is scattered. The method for manufacturing a liquid crystal element as described in claim 12, wherein the liquid crystal alignment agent coated on the electrode arrangement surface is heated at a temperature below 160°C. The method for manufacturing a liquid crystal element as described in item 12 or 13 of the scope of patent application, wherein the liquid crystal alignment agent is coated on the electrode arrangement surface of at least one of the pair of base materials to form a coating film, The coating film is irradiated with light, thereby imparting liquid crystal alignment ability to the coating film.

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