JP6870689B2 - Liquid crystal elements, their manufacturing methods, and display devices - Google Patents

Description

Cross-reference of related applications

This application is based on Japanese Application No. 2017-10532 filed on January 24, 2017, the contents of which are incorporated herein by reference.

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

As a liquid crystal element, in recent years, a polymer-dispersed liquid crystal element in which a liquid crystal layer made of a composite material of a liquid crystal and a polymer is arranged between a pair of film substrates on which a transparent electrode is formed on the surface is known. Therefore, it has been proposed to use such a polymer-dispersed liquid crystal element as a dimming element (see, for example, Patent Document 1 and Patent Document 2). The dimming elements of Patent Document 1 and Patent Document 2 exhibit a dimming function by changing the transparency by switching between voltage application and voltage non-application of the transparent electrode. In addition, it is being considered to add new functions to show windows, smartphones, televisions, monitors, buildings, furniture, etc. by using such dimming functions. As the polymer-dispersed liquid crystal, for example, PDLC (Polymer Dispersed Liquid Cristal) and PNLC (Polymer Network Liquid Cristal) are known.

Patent Document 3 proposes a display device in which a liquid crystal display panel is arranged on the back surface of a transparent display made of an organic EL element. In this display device, it has been proposed to control the light transmission by controlling the voltage applied to the liquid crystal display panel, thereby improving the visibility of the display of the transparent display. Further, Patent Document 4 describes a reverse type liquid crystal element in which light is transmitted and becomes transparent when a voltage is not applied between a pair of electrodes, and light is scattered and becomes a non-transparent state when a voltage is applied. It is disclosed. The reverse type liquid crystal element described in Patent Document 4 has a polyimide film as an alignment film for vertically aligning the liquid crystal, and the orientation state of the liquid crystal molecules in the liquid crystal layer is controlled by the polyimide film.

Japanese Unexamined Patent Publication No. 2013-3319 Japanese Unexamined Patent Publication No. 2013-148744 Japanese Unexamined Patent Publication No. 2008-083510 International Publication No. 2015/022980

In the design of alignment film materials for liquid crystal display panels of liquid crystal televisions and the like, polyimide-based materials have been effectively used from the viewpoint of ensuring characteristics such as liquid crystal orientation and electrical characteristics. On the other hand, the priority of various characteristics required for the liquid crystal alignment film differs between the liquid crystal display panel and the light control element. For example, when it is used as a dimming element, it is required that the liquid crystal element is thinner and has a variety of shapes than the characteristics related to display quality such as liquid crystal orientation and electrical characteristics.

One of the methods for reducing the thickness of the liquid crystal element and improving the variety of shapes is to reduce the thickness of the base material and widen the range of material selection. For example, applying a base material made of a polymer material. Can be considered. Further, in order to make a base material made of a polymer material applicable, it is required that the polymer used as the alignment film material has excellent solubility in a low boiling point solvent. However, the polyimide resin is generally difficult to dissolve in a low boiling point solvent, and there is a concern that a uniform liquid crystal alignment film cannot be obtained due to many uneven film thickness, uneven coating, and pinholes in the obtained coating film.

Further, the liquid crystal alignment film using the polyimide resin is easily colored, and when applied to a light control element, transparency in a light transmitting state may become a problem. Further, since the dimming element is expected to be applied for outdoor use, it may be necessary to have excellent weather resistance.

The present disclosure has been made in view of the above problems, and when a base material made of a polymer material is applied, the liquid crystal alignment film is homogeneous and highly transparent, and has good light transmission characteristics and light scattering characteristics. The main purpose of the present invention is to provide a liquid crystal element which exhibits sufficient electrical characteristics to realize a dimming function and has excellent weather resistance.

The present disclosure employs the following means in order to solve the above problems.

[1] A liquid crystal composition which is arranged between a pair of base materials arranged to face each other, electrodes arranged on surfaces facing each other in the pair of base materials, and a liquid crystal and a polymerizable compound. A liquid crystal layer formed by curing an object and a liquid crystal alignment film formed on at least one electrode arrangement surface of the pair of base materials are provided, and the liquid crystal composition is simply used as the polymerizable compound. The liquid crystal alignment film contains at least one selected from the group consisting of a functional (meth) acrylate compound, a polyfunctional (meth) acrylate compound, a polyfunctional thiol compound, and a styrene-based compound, and the liquid crystal alignment film contains a poly (meth) acrylate. A liquid crystal element formed of an agent.
[2] A display device including the liquid crystal element of the above [1] and a transparent display that becomes transparent in a non-display state.
[3] A liquid crystal having a liquid crystal layer formed by curing a liquid crystal and a liquid crystal composition containing a polymerizable compound between a pair of base materials arranged so that electrodes provided on each base material surface face each other. A liquid crystal alignment agent for forming a liquid crystal alignment film of an element, which contains a poly (meth) acrylate.
[4] A liquid crystal having a liquid crystal layer formed by curing a liquid crystal and a liquid crystal composition containing a polymerizable compound between a pair of base materials arranged so that electrodes provided on each base material surface face each other. A method for manufacturing an element, which is a step of applying a liquid crystal alignment agent on at least one electrode arrangement surface of the pair of base materials to form a liquid crystal alignment film, and a step of forming the liquid crystal alignment film and then the pair of base materials. A step of constructing a liquid crystal cell by arranging the electrodes so as to face each other via a layer containing the liquid crystal composition, and a step of curing the polymerizable compound after the construction of the liquid crystal cell. The liquid crystal composition contains, as the polymerizable compound, at least one selected from the group consisting of a monofunctional (meth) acrylate compound, a polyfunctional (meth) acrylate compound, a polyfunctional thiol compound and a styrene-based compound, and the liquid crystal alignment agent. Is a method for manufacturing a liquid crystal element containing a poly (meth) acrylate.

According to the above configuration, even when a base material made of a polymer material is applied as a pair of base materials, a liquid crystal element having a homogeneous and highly transparent liquid crystal alignment film can be obtained. Further, even when a base material made of a polymer material is applied, the liquid crystal has good light transmission characteristics and light scattering characteristics, exhibits sufficient electrical characteristics to realize a dimming function, and has excellent weather resistance. The element can be obtained.

The figure which shows the schematic structure of the liquid crystal element. The figure explaining the function of a liquid crystal element. The figure which shows the schematic structure of the display device which includes a liquid crystal element and a transparent display.

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

<Liquid crystal element>
As shown in FIG. 1, the liquid crystal element 10 of the present embodiment has a pair of base materials composed of the first base material 11 and the second base material 12 and between the first base material 11 and the second base material 12. It includes an arranged liquid crystal layer 13. The liquid crystal layer 13 is a polymer-dispersed liquid crystal layer which is a polymer / liquid crystal composite material layer in which a polymer 13a and a liquid crystal molecule 13b are mixed. In this embodiment, a polymer dispersion in which a polymer network is formed is formed. It is a type liquid crystal (PDLC). The liquid crystal element 10 is a dimming element that switches between a transmissive state in which light is transmitted and a non-transmissive state in which light is scattered by controlling the orientation of the liquid crystal molecules 13b existing in the polymer network by an electric field.

The first base material 11 and the second base material 12 are transparent base materials made of a polymer material. Examples of the polymer material constituting the base material include silicon, polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, polypropylene, polyvinyl chloride, aromatic polyamide, polyamideimide, polyimide, and triacetylcellulose (TAC). Examples include materials such as polymethylmethacrylate. The first base material 11 and the second base material 12 may be used as a glass substrate, but a plastic substrate is particularly preferable in order to reduce the thickness and weight of the liquid crystal element.

In the first base material and the second base material 12, transparent electrodes 16 and 17 are arranged on the surfaces facing each other, and an electrode pair is constructed by these transparent electrodes 16 and 17, respectively. In the present embodiment, the transparent electrodes 16 and 17 are transparent conductive films, for example, a NESA film (registered trademark of PPG, USA) made of _{tin oxide (SnO 2 ), indium tin oxide-tin oxide (In 2} O _{3- SnO 2} ). It is an ITO film made of, or a film made of a carbon material. The transparent electrodes 16 and 17 may have a predetermined pattern such as a comb tooth shape.

Liquid crystal alignment films 14 and 15 are formed on the electrode arrangement surfaces of the first base material 11 and the second base material 12, respectively. The liquid crystal alignment films 14 and 15 are organic thin films that regulate the orientation of the liquid crystal molecules in the liquid crystal layer 13, and in the present embodiment, they are formed by using a polymer composition containing a polymer having a photooriented group. It is a photo-alignment film. The liquid crystal alignment films 14 and 15 may be provided on at least one of the pair of substrates, but are preferably provided on both substrates from the viewpoint of orientation stability. After arranging the liquid crystal composition in the space surrounded by the pair of base materials and the sealant (not shown) arranged so as to surround the outer edge portion of the electrode arrangement surface between the pair of base materials, the liquid crystal layer 13 is formed. It is formed by curing the liquid crystal composition. The liquid crystal composition contains a liquid crystal and a polymerizable compound.

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 that the light absorption loss is small and the light utilization efficiency is high.

2A and 2B are views for explaining the function of the liquid crystal element 10, in which FIG. 2A shows a state in which no voltage is applied between the transparent electrodes 16 and 17, and FIG. 2B shows a state in which a voltage is not applied between the transparent electrodes 16 and 17. Indicates a state in which a voltage is applied. The liquid crystal element 10 is a reverse type PDLC, and when no voltage is applied between the transparent electrodes 16 and 17, the incident light is transmitted from one of the pair of substrates to the other and becomes transparent, so that the transparent electrodes 16 and 17 become transparent. When a voltage is applied between them, the orientation state of the liquid crystal molecules 13b changes, so that the incident light is scattered and becomes a non-transparent state. In the present embodiment, as shown in FIG. 2, in the voltage-free state, the long axis direction of the liquid crystal molecules 13b is the direction perpendicular to the substrate surface, so that the liquid crystal element 10 becomes transparent and the voltage is applied. Then, the liquid crystal elements 13b are rotated in the direction parallel to the substrate surface, so that the liquid crystal element 10 is in a non-transparent state. By switching between application and non-application of such a voltage, the liquid crystal element 10 exhibits a dimming function. The liquid crystal element 10 has, for example, a film shape or a plate shape. 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 for forming 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 a nematic liquid crystal and a smectic liquid crystal.

The polymerizable compound is preferably a compound exhibiting radical polymerizable property, and is at least selected from the group consisting of a monofunctional (meth) acrylate compound, a polyfunctional (meth) acrylate compound, a polyfunctional thiol compound, and a styrene compound. It is particularly preferable to contain a kind of compound (hereinafter, also referred to as "specific polymerizable compound"). In addition, in this specification, "(meth) acrylate" means containing acrylate and methacrylate.

Specific examples of the polymerizable compound include monofunctional (meth) acrylate compounds such as (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, and n-hexyl. Alkyl (meth) acrylates such as (meth) acrylate and 2-ethylhexyl (meth) acrylate; cycloalkyl (meth) acrylates such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate; aryl such as benzyl (meth) acrylate (Meta) acrylates;
2-methoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, 2-phenylphenoxyethyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate , Ethanol-based (meth) acrylates such as ethoxylated o-phenylphenol (meth) acrylate, ethyldiethylene glycol (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate;
Alcohol-based (meth) acrylates such as 2-hydroxyethyl (meth) acrylate; carboxylic acid-based (meth) acrylates such as 2- (meth) acryloyloxyethyl succinic acid and 2- (meth) acryloyloxyethyl hexahydrophthalic acid. Classes: Nitrogen-containing unsaturated compounds such as acrylamide, (meth) acryloylmorpholine, isobutoxymethyl (meth) acrylamide, vinylcaprolactam, N-vinyl-2-pyrrolidone; tetrabromophenyl (meth) acrylate, pentachlorophenyl (meth) acrylate. Such as halogenated (meth) acrylates; 3- (meth) acryloxypropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, etc.;

Examples of the polyfunctional (meth) acrylate compound include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and neopentyl glycol di. (Meta) Acrylate, (Meta) Acryloyloxypivalate (Meta) Acryloyloxypivalate, 2-Hydroxy-3-Acryloyloxypropyl (Meta) Acrylate, Tripropylene Glycoldi (Meta) Acrylate, Tetraethylene Glycoldi (Meta) ) Acrylate, 1,9-nonanediol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, trimethylolpropane (Meta) Acrylate, Trimethylol Propanetri (Meta) Acrylate, Ditrimethylol Propanetetra (Meta) Acrylate, Urethane (Meta) Acrylate Compound (For example, phenylglycidyl ether (meth) acrylate hexamethylenediisocyanate urethane prepolymer, pentaerythritol Tri (meth) acrylate hexamethylene diisocyanate urethane prepolymer, dipentaerythritol penta (meth) acrylate hexamethylene diisocyanate), etc.;

Examples of the polyfunctional thiol compound include 1,3-propanedithiol, 1,4-butanedithiol, 1,6-hexanedithiol, 2,5-hexanedithiol, 1,8-octanedithiol, 1,9-nonandithiol, and the like. 3,7-Dithia-1,9-nonandithiol, 1,4-bis (3-mercaptobutylyloxy) butane, tetraethylene glycol bis (3-mercaptopropionate), dimercaptobenzene, 1,2-di (Mercaptomethyl) benzene, 1,3-di (mercaptomethyl) benzene, 1,4-di (mercaptomethyl) benzene, 1,3-dimercapto-5-methyl-benzene, 4,5-dimercapto-1,3, Dithiol compounds such as 4-thiazol, 1,4-bis (2-mercaptoethyl) benzene, esters of thiol group-containing carboxylic acids and divalent alcohols;
Isocyanuric acid, trimethylolpropane, 2,4,6-trimercapto-1,3,5-triazine, 1,3,5-tris (3-mercaptobutylyloxyethyl) -1,3,5-triazine-2 , 4, 6 (1H, 3H, 5H) -Trione, trimethylolpropane tris (3-mercaptobutyrate), trimethylolpropane tris (3-mercaptopropionate), tris-[(3-mercaptopropionyloxy)- Ethyl] -Isocyanurate, trimethylolethanetris (3-mercaptobutyrate), pentaerythritol tetrakis (3-mercaptobutyrate), pentaerythritol tetrakis (3-mercaptopropionate), dipentaerythritol hexakis (3-mercapto) Propionate), polyfunctional polymer having a thiol group (for example, under the trade name, thiocol LP (registered trademark), polythiol (registered trademark) (all manufactured by Toray Fine Chemicals Co., Ltd.)), thiol group-containing carboxylic acid. Polythiol compounds such as polyesters and polyhydric alcohols; examples of styrene compounds include styrene and methylstyrene, respectively.

Although one type of the polymerizable compound may be used alone, it is preferable to use two or more types in combination from the viewpoint of improving the optical characteristics. Specifically, the liquid crystal composition preferably contains a monofunctional (meth) acrylate compound and a polyfunctional (meth) acrylate compound as the polymerizable compound, and the monofunctional (meth) acrylate compound and the polyfunctional (meth) acrylate. More preferably, it contains a compound and a polyfunctional thiol compound. Further, it is particularly preferable that the urethane (meth) acrylate compound is contained as at least a part of the monofunctional (meth) acrylate compound and the polyfunctional (meth) acrylate compound.

The content ratio of the polymerizable compound in the liquid crystal composition is appropriately selected according to the type of the compound. For example, the content ratio of the monofunctional (meth) acrylate compound is preferably 10 to 300 parts by mass and more preferably 20 to 200 parts by mass with respect to 100 parts by mass of the total liquid crystal. The content ratio of the polyfunctional (meth) acrylate compound is preferably 1 to 200 parts by mass, and more preferably 5 to 100 parts by mass with respect to 100 parts by mass of the total liquid crystal.
When the urethane (meth) acrylate compound is contained, the content ratio thereof is preferably 1 to 150 parts by mass, more preferably 5 to 100 parts by mass with respect to 100 parts by mass of the total liquid crystal. ..
The content ratio of the polyfunctional thiol compound is preferably 0.5 to 50 parts by mass, and more preferably 1 to 40 parts by mass with respect to 100 parts by mass of the total liquid crystal. The blending ratio of the styrene compound is preferably 0.1 to 30 parts by mass, and more preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the total liquid crystal.
The content ratio of the polymerizable compound in the liquid crystal composition (the total amount when two or more kinds are contained) is preferably 1 to 90% by mass with respect to the total amount of the liquid crystal and the polymerizable compound. It is more preferably ~ 80% by mass, and even more preferably 10 to 75% by mass.

The ratio of the specific polymerizable compound used is preferably 70% by mass or more, more preferably 80% by mass or more, and 90% by mass or more, based on the total amount of the polymerizable compound contained in the liquid crystal composition. It is more preferable to do so. The polymerizable compound contained in the liquid crystal composition is particularly preferably composed of 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 enhancing the polymerizable property of the polymerizable compound and promoting the formation of a polymer network in the liquid crystal layer 13 (preferably over the entire liquid crystal layer 13), a polymerization initiator is contained as another component. Is preferable.

The polymerization initiator contained in the liquid crystal composition may be a compound (light initiator) capable of initiating the polymerization of the polymerizable compound by irradiation with radiation such as visible light, ultraviolet rays, far ultraviolet rays, electron beams, and X-rays. preferable. The photoinitiator is preferably a radical polymerization initiator capable of generating radicals by light irradiation, and specific examples thereof include acetophenone, benzophenone, 2-benzoylbenzoic acid, and 4,4'-bis (diethylamino). Benzophenone, 2-methoxy-2-phenylacetophenone, 2-isobutoxy-2-phenylacetophenone, 2- (1,3-benzodioxol-5-yl) -4,6-bis (trichloromethyl) -1,3 , 5-Triazine, 2-Methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propanol, acetophenone benzyl ketal, 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, Benzylaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, benzyldimethylketal, 1- (4-isopropyl) Phenyl) -2-hydroxy-2-methylpropan-1-one, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-isopropylthioxanthone, 2-chlorothioxanthone, diphenyl (2,4,6) -Trimethoxybenzoyl) phosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, 2-hydroxy-1- [4- [4- (2-hydroxy-2-) Methylpropionyl) benzyl] phenyl] -2-methylpropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2,4,6-trimethylbenzoyl-diphenyl Phosphine oxide, 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], etanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H -Carbazole-3-yl]-, 1- (O-acetyloxime), 4,4'-bis (diethylamino) benzophenone, 4- (diethylamino) benzophenone, 2-hydroxy-2-phenylacetophenone, 4,4'- Examples thereof include dimethoxybenzyl, diphenylethanedione, 2-benzyl-2- (dimethylamino) -1- [4- (morpholino) phenyl] -1-butanone and the like.

The content ratio of the polymerization initiator in the liquid crystal composition is a component other than the solvent contained in the liquid crystal composition from the viewpoint of promptly performing the curing reaction and suppressing a decrease in curability due to addition of an excessive amount. It is preferably 0.1 to 10% by mass, more preferably 0.5 to 8% by mass, and even more preferably 1 to 7% by mass with respect to the total mass of (solid content). The polymerization initiator may be used alone or in combination of two or more.

A dye may be used as another component to be blended in the liquid crystal composition. By using the dye, the liquid crystal element 10 in which the dye is dispersed in the liquid crystal layer 13 can be obtained. Further, according to the liquid crystal element 10 of the present disclosure, even when the dye is dispersed in the liquid crystal layer 13, the change in light shading / light transmission due to switching between application and non-application of voltage is clear, and also. , It is preferable in that the durability when repeatedly driven is also good.
As the dye, a dichroic dye can be preferably used. The dichroic dye to be used is not particularly limited, and known compounds can be appropriately used, and examples thereof include polyiodine, azo compounds, anthraquinone compounds, and dioxazine compounds. Of these, at least one selected from the group consisting of azo compounds and anthraquinone compounds is preferable, and azo compounds are particularly preferable, because they have excellent light resistance and a high two-color ratio. As the dye, one type may be used alone, or two or more types may be combined.

The blending ratio of the dyes (in the case of blending two or more kinds, the total amount thereof) is preferably 0.05 to 5% by mass with respect to the total mass of the solid content in the liquid crystal composition. It is more preferably 1 to 3% by mass.

The liquid crystal composition is prepared by mixing the liquid crystal, the polymerizable compound, and other components added as needed. The treatment for mixing these components may be performed at room temperature or while raising the temperature. It is also possible to dissolve each component in a suitable organic solvent and then remove the solvent by, for example, a distillation operation.

<Liquid crystal alignment agent>
Next, the liquid crystal alignment agent used for forming the liquid crystal alignment films 14 and 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 that it includes polyacrylate and polymethacrylate.

(Poly (meth) acrylate)
Examples of the poly (meth) acrylate include a method in which a monomer having a (meth) acryloyl group (hereinafter, also referred to as “(meth) acrylic monomer”) is reacted in the presence of a polymerization initiator. .. In the poly (meth) acrylate used for preparing the liquid crystal aligning agent, the ratio of the (meth) acrylic monomer used to the total amount of the monomers used for the polymerization is preferably 20% by mass or more, more preferably. Is 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 for the polymerization is not particularly limited, and is, for example, an unsaturated carboxylic acid such as (meth) acrylic acid, α-ethylacrylic acid, maleic acid, fumaric acid, itaconic acid, and vinyl benzoic acid. Acids: Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, allyl (meth) acrylate, cyclohexyl (meth) acrylate, tricyclo (meth) acrylate [5.2.1.0 ^2,6 ] Deca-8-yl, dicyclopentanyl (meth) acrylate, benzyl (meth) acrylate, -2-ethylhexyl (meth) acrylate, (meth) acrylate Lauryl, (meth) acrylic acid trimethoxysilylpropyl, (meth) acrylic acid 2,2,2-trifluoroethyl, (meth) acrylic acid 2,2,3,3,3-pentafluoropropyl, (meth) acrylic Methoxyethyl acid, -N, N-dimethylaminoethyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth) acrylic Unsaturated carboxylic acid esters such as glycidyl acid, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxybutyl (meth) acrylate, 4-hydroxybutyl glycidyl ether acrylate: maleic anhydride, itacon anhydride Examples thereof include acidic, unsaturated polyvalent carboxylic acid anhydrides such as cis-1,2,3,4-tetrahydrophthalic acid anhydride, and the like. As the (meth) acrylic monomer, one of these can be used alone or in combination of two or more.

The (meth) acrylic monomer used for the polymerization has an epoxy group (meth) from the viewpoint of improving the liquid crystal orientation and electrical characteristics of the obtained liquid crystal element 10 and the adhesiveness of the liquid crystal alignment film to the substrate. ) It is preferable to contain an acrylic monomer. The ratio of the (meth) acrylic monomer having an epoxy group is preferably 1% by mass or more, more preferably 5% by mass or more, based on the total amount of the monomers used for the polymerization. It is more preferably 10% by mass or more.

In addition, in the polymerization, a monomer other than the (meth) acrylic monomer may be used. Examples of other monomers include conjugated diene compounds such as 1,3-butadiene, 2-methyl-1,3-butadiene; aromatic vinyl compounds such as styrene, methylstyrene and divinylbenzene; and maleimide group-containing compounds. Can be mentioned. The ratio of the other monomers is preferably 80% by mass or less, more preferably 70% by mass or less, based on the total amount of the monomers used in the synthesis of the poly (meth) acrylate. It is more preferably 60% by mass or less.

The poly (meth) acrylate contained in the liquid crystal alignment agent has a side chain structure (hereinafter, also referred to as “specific side chain structure”) included in the group consisting of (a) to (e) shown below. It is preferable not to.
(A) Alkyl group having 8 to 22 carbon atoms (b) Fluorine-containing alkyl group having 6 to 18 carbon atoms (c) Any ring of benzene ring, cyclohexane ring and heterocycle, and 1 to 20 carbon atoms. Group having an alkyl group or a fluorine-containing alkyl group bonded to it (d) A group having at least two or more rings selected from the group consisting of a benzene ring, a cyclohexane ring and a heterocycle (e) having a steroid skeleton. Group with 17-51 carbon atoms

（式（５）中、Ａ^１〜Ａ^３は、それぞれ独立に、フェニレン基又はシクロへキシレン基であり、環部分に置換基を有していてもよい。Ｒ^２１は、水素原子、炭素数１〜２０のアルキル基、炭素数１〜２０のアルコキシ基、少なくとも１個の水素原子がフッ素原子で置換された炭素数１〜２０のフッ素含有アルキル基、少なくとも１個の水素原子がフッ素原子で置換された炭素数１〜２０のフッ素含有アルコキシ基、又はフッ素原子であり、Ｒ^２２及びＲ^２３は、それぞれ独立に、単結合、−Ｏ−、−ＣＯＯ−、−ＯＣＯ−又は炭素数１〜３のアルカンジイル基である。ｋ、ｍ及びｎは、１≦ｋ＋ｍ＋ｎ≦４を満たす０以上の整数である。Ｒ^２１が水素原子、炭素数１〜３のアルキル基又はフッ素原子の場合、ｋ＋ｍ＋ｎ≧２を満たす。「＊」は結合手を示す。）As a specific example of the specific side chain structure, as the alkyl group of (a), for example, n-octyl group, n-nonyl group, n-decyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n. -Heptadecyl group, n-octadecyl group, etc.; as the fluorine-containing alkyl group of (b), for example, a group in which at least one hydrogen atom of the alkyl group of (a) above is replaced with a fluorine atom; Examples of the group and the group (d) include a group represented by the following formula (5); and as the group (e), for example, a cholestanyl group, a cholesteryl group, a lanostenyl group and the like can be mentioned.

(In the formula (5), A ^{1 to} A ³ are independently phenylene groups or cyclohexylene groups, and may have a substituent on the ring portion. R ²¹ is a hydrogen atom and the number of carbon atoms. An alkyl group of 1 to 20, an alkoxy group having 1 to 20 carbon atoms, a fluorine-containing alkyl group having 1 to 20 carbon atoms in which at least one hydrogen atom is replaced with a fluorine atom, and at least one hydrogen atom being a fluorine atom. Substituted fluorine-containing alkoxy groups having 1 to 20 carbon atoms or fluorine atoms, and R ²² and R ²³ are independently single-bonded, -O-, -COO-, -OCO- or 1 to 1 carbon atoms. The alkylandyl group of 3. k, m and n are integers of 0 or more satisfying 1 ≦ k + m + n ≦ 4. When R ²¹ is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or a fluorine atom, k + m + n ≧ 2 is satisfied. “*” Indicates a bond.)

（式中、「＊」は結合手を示す。）Specific examples of the group represented by the above formula (5) include, but are limited to, for example, the groups represented by each of the following formulas (5-1) to (5-10). is not it. 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.

(In the formula, "*" indicates a bond.)

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), and 2,2'-azobis (4). Azo compounds such as −methoxy-2,4-dimethylvaleronitrile); organic peroxides such as benzoyl peroxide, lauroyl peroxide, t-butylperoxypivalate, 1,1′-bis (t-butylperoxy) cyclohexane; Hydrogen oxide; Redox-type initiators composed of these peroxides and reducing agents can be mentioned. Of these, azo compounds are preferred. As the polymerization initiator, these can be used alone or in combination of two or more. The proportion of the polymerization initiator used is preferably 0.01 to 50 parts by mass, more preferably 0.1 to 40 parts by mass, based on 100 parts by mass of the total amount 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 the reaction include alcohols, ethers, ketones, amides, esters, hydrocarbon compounds and the like. 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. Preferred specific examples thereof include diethylene glycol methyl ethyl ether and propylene glycol monomethyl ether acetate. As the organic solvent, one of these can be used alone or in combination of two or more.

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

For poly (meth) acrylate, the polystyrene-equivalent number average molecular weight (Mn) measured by gel permeation chromatography (GPC) improves the liquid crystal orientation of the formed liquid crystal alignment film and of the liquid crystal orientation. From the viewpoint of ensuring stability over time, it is preferably 250 to 500,000, more preferably 500 to 100,000, and even more preferably 1,000 to 50,000.

The content ratio of the poly (meth) acrylate in the liquid crystal aligning agent is a liquid crystal from the viewpoint of obtaining a liquid crystal element 10 having sufficiently high transparency while sufficiently obtaining the effect of improving the coatability when a low boiling point solvent is used. It is preferably 3 to 99% by mass with respect to the total amount of the polymer components of the orienting agent. The lower limit of the content ratio is more preferably 5% by mass or more, further preferably 20% by mass, and particularly preferably 50% by mass. Further, the upper limit of the content ratio of the poly (meth) acrylate is more preferably 95% by mass or less, still more preferably 90% by mass, when the effect of improving various properties by a polymer different from the poly (meth) acrylate is obtained. % Or less. As the poly (meth) acrylate, one type may be used alone, or two or more types may be used in combination.

(Other ingredients)

The liquid crystal aligning agent used for forming the liquid crystal alignment films 14 and 15 is at least one selected from the group consisting of a silane compound and a polysiloxane together with poly (meth) acrylate in that a liquid crystal element 10 having high weather resistance can be obtained. Is preferably contained. It is particularly preferable that the liquid crystal alignment agent contains polysiloxane because it has a high effect of improving weather resistance and can further reduce the post-bake temperature. Further, the liquid crystal alignment agent preferably contains a silane compound in that the adhesion to the substrate can be further improved.

(Polysiloxane)
Polysiloxane can be obtained, for example, by hydrolyzing and condensing a hydrolyzable silane compound. Examples of the silane compound include tetraalkoxysilane compounds such as tetramethoxysilane and tetraethoxysilane; alkyl and aryl group-containing alkoxysilanes such as methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane and dimethyldiethoxysilane. Compound;
3-Sulfur-containing alkoxysilane compounds such as mercaptopropyltriethoxysilane and mercaptomethyltriethoxysilane;
Glycydoxymethyltrimethoxysilane, glycidoxymethyltriethoxysilane, 2-glycidoxyethyltrimethoxysilane, 2-glycidoxyethyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycid Epoxy group-containing alkoxysilane compounds such as xypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane;
Unsaturated bond-containing alkoxysilane compounds such as 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxypropylmethyldiethoxysilane, vinyltriethoxysilane ;
3-Aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N -(2-Aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane and other nitrogen-containing alkoxysilanes. Compound;
Alkoxysilane compounds containing an acid anhydride group such as trimethoxysilylpropyl succinic anhydride; and the like can be mentioned. The hydrolyzable silane compound may be used alone or in combination of two or more. In addition, "(meth) acryloxy" has a meaning including "acryloxy" and "methacryloxy".

The above-mentioned hydrolysis / condensation reaction is carried out by reacting one or more of the above-mentioned hydrolyzable silane compounds with water, preferably in the presence of a suitable catalyst and organic solvent. In the reaction, the ratio of water used is preferably 1 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 varies depending on the type of catalyst, reaction conditions such as temperature, and should be set appropriately, but is preferably 0.01 to 3 times the molar amount of the total amount of the silane compound, for example. .. Examples of the organic solvent to be used include hydrocarbons, ketones, esters, ethers, alcohols and the like, and among these, it is preferable to use a water-insoluble or poorly water-soluble organic solvent. The proportion of the organic solvent used is preferably 10 to 10,000 parts by mass with respect to a total of 100 parts by mass of the silane compound used in the reaction.

The above hydrolysis / condensation reaction is preferably carried out by heating in, for example, an oil bath. At that time, the heating temperature is preferably 130 ° C. or lower, and the heating time is preferably 0.5 to 12 hours. After completion of the reaction, the organic solvent layer separated from the reaction solution is dried with a desiccant, if necessary, and then the solvent is removed to obtain the desired polysiloxane. The method for synthesizing polysiloxane is not limited to the above-mentioned hydrolysis / condensation reaction, and may be carried out by, for example, a method of reacting a hydrolyzable silane compound in the presence of oxalic acid and alcohol.

The liquid crystal aligning agent may contain a polysiloxane having a functional group such as a photo-oriented group or a pre-tilt angle-imparting group (for example, a vertically oriented group shown below) in the side chain. A polysiloxane having such a functional group is obtained by, for example, synthesizing a polysiloxane having an epoxy group in a side chain by polymerization using a hydrolyzable silane compound containing an epoxy group in at least a part of a raw material, and then an epoxy group. It can be obtained by reacting a polysiloxane having the above with a carboxylic acid having a functional group. Alternatively, a polymerization method using a hydrolyzable silane compound having a functional group as a monomer may be adopted.

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

Preferred specific examples of the organic solvent used include 2-butanone, 2-hexanone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, butyl acetate and the like. The organic solvent is preferably used in a proportion such that the solid content concentration is 5 to 50% by mass. The reaction temperature in the above reaction is preferably 0 to 200 ° C., and the reaction time is preferably 0.1 to 50 hours. After completion of the reaction, the organic solvent layer separated from the reaction solution is dried with a desiccant if necessary, and then the solvent is removed to obtain a polysiloxane having a functional group.

The polysiloxane preferably has a group capable of vertically aligning liquid crystal molecules (hereinafter, also referred to as "vertically oriented group"). Specifically, as the vertically oriented group, for example, an alkyl group having 8 to 22 carbon atoms, a fluorine-containing alkyl group having 6 to 18 carbon atoms, a group represented by the above formula (5), and a carbon number having a steroid skeleton. 17-51 groups and the like can be mentioned. When a polysiloxane having a vertically oriented group is contained in the liquid crystal aligning agent, the light transmittance and light scattering property of the obtained liquid crystal element can be further improved, which is preferable.

For polysiloxane, the polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC) is preferably 500 to 1,000,000, more preferably 1,000 to 100,000. Further, it is preferably 1,000 to 50,000.

The content ratio of polysiloxane in the liquid crystal alignment agent shall be 1% by mass or more with respect to the total amount of the polymer components in the liquid crystal alignment agent from the viewpoint of sufficiently increasing the weather resistance of the obtained liquid crystal element 10. Is preferable, and it is more preferably 2% by mass or more, and further preferably 5% by mass or more. The upper limit of the content ratio of polysiloxane is preferably 97% by mass or less, and more preferably 90% by mass or less. One type of polysiloxane may be used alone, or two or more types may be used in combination.

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

When the silane compound is blended with the liquid crystal alignment agent, the blending ratio is 0 with respect to a total of 100 parts by mass of the polymer from the viewpoint of sufficiently obtaining the effect of improving the adhesion to the substrate and the weather resistance of the liquid crystal element 10. It is preferably .5 parts by mass or more, and more preferably 1 to 30 parts by mass. The silane compound may be used alone or in combination of two or more.

（式（１）中、Ｒは、炭素数１〜１０のアルキル基、炭素数１〜１０のアルコキシ基、少なくとも１個の水素原子がフッ素原子で置換された炭素数１〜１０のフッ素含有アルキル基、少なくとも１個の水素原子がフッ素原子で置換された炭素数１〜１０のフッ素含有アルコキシ基、又はフッ素原子である。ａは０〜４の整数である。ａが２以上の場合、複数のＲは同一でも異なっていてもよい。「＊」は結合手を示す。）(Polymer having a photo-oriented group)
The liquid crystal alignment agent used for forming the liquid crystal alignment films 14 and 15 preferably contains a polymer having a photoalignment group. Here, the "photo-oriented group" means a functional group that imparts anisotropy to the film by a photoisomerization reaction, a photodimerization reaction, a photodecomposition reaction, or a photofries rearrangement reaction by light irradiation. Specific examples of the photoorientating group include an azobenzene-containing group containing azobenzene or a derivative thereof as a basic skeleton, a lauric acid structure-containing group containing katsura acid or a derivative thereof as a basic skeleton, and a chalcone containing chalcone or a derivative thereof as a basic skeleton. Examples thereof include a containing group, a benzophenone-containing group containing benzophenone or a derivative thereof as a basic skeleton, a coumarin-containing group containing coumarin or a derivative thereof as a basic skeleton, and a cyclobutane-containing structure containing cyclobutane or a derivative thereof as a basic skeleton. Among these, a cinnamic acid structure-containing group is preferable in terms of high sensitivity to light, and examples thereof include a group having a partial structure represented by the following formula (1).

(In the formula (1), R is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and a fluorine-containing alkyl having 1 to 10 carbon atoms in which at least one hydrogen atom is replaced with a fluorine atom. A group, a fluorine-containing alkoxy group having 1 to 10 carbon atoms in which at least one hydrogen atom is replaced with a fluorine atom, or a fluorine atom. A is an integer of 0 to 4. When a is 2 or more, a plurality of groups. R may be the same or different. “*” Indicates a bond.)

（式（４）中、Ｒ^１１は、フェニレン基、ビフェニレン基、ターフェニレン基、シクロヘキシレン基又はビシクロヘキシレン基であり、環部分に、炭素数１〜２０のアルキル基、炭素数１〜２０のアルコキシ基、少なくとも１個の水素原子がフッ素原子で置換された炭素数１〜２０のフッ素含有アルキル基、少なくとも１個の水素原子がフッ素原子で置換された炭素数１〜２０のフッ素含有アルコキシ基、又はフッ素原子を有していてもよい。Ｒ^１２は、式（１）中のベンゼン環に結合している場合には、単結合、炭素数１〜３のアルカンジイル基、酸素原子、硫黄原子、−ＣＨ＝ＣＨ−、−ＮＨ−、−ＣＯＯ−又は−ＯＣＯ−であり、式（１）中のカルボニル基に結合している場合には、単結合、炭素数１〜３のアルカンジイル基、酸素原子、硫黄原子又は−ＮＨ−である。「＊」は結合手を示す。）In the partial structure represented by the above formula (1), one of the two bonding hands "*" is preferably bonded to the group represented by the following formula (4). In this case, the light transmittance and light scattering property of the obtained liquid crystal element can be improved, which is preferable.

(In the formula (4), R ¹¹ is a phenylene group, a biphenylene group, a terphenylene group, a cyclohexylene group or a bicyclohexylene group, and has an alkyl group having 1 to 20 carbon atoms and 1 to 20 carbon atoms in the ring portion. Alkoxy group, a fluorine-containing alkyl group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom, and a fluorine-containing alkoxy group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom. group, or optionally .R ¹² may have a fluorine atom, when bound to the benzene ring in formula (1) is a single bond, alkanediyl group having 1 to 3 carbon atoms, an oxygen atom, When the sulfur atom is −CH = CH−, −NH−, −COO− or −OCO− and is bonded to the carbonyl group in the formula (1), it is a single bond and an alkane having 1 to 3 carbon atoms. It is a diyl group, an oxygen atom, a sulfur atom or -NH-. "*" Indicates a bond.)

The photo-oriented group may be contained in the poly (meth) acrylate, but may be contained in a polymer different from the poly (meth) acrylate. Examples of the main skeleton of the polymer having a photo-oriented group include polyamic acid, polyamic acid ester, polyimide, polysiloxane, polyamide and the like. From the viewpoint of ensuring the reliability and weather resistance of the liquid crystal element 10, a polysiloxane having a photooriented group can be preferably used.

The method for synthesizing the polymer having a photo-oriented group is not particularly limited, and may be appropriately selected depending on the main skeleton of the polymer. Specific examples include (1) a method of polymerizing using a monomer having a photo-oriented group, (2) synthesizing a polymer having a first functional group (for example, an epoxy group) in a side chain, and then first. Examples thereof include a method of reacting a reactive compound having a second functional group (for example, a carboxyl group) and a photoalignable group capable of reacting with the functional group of the above with a polymer having the first functional group. When the polymer having a photo-oriented group is polysiloxane, the method (2) is preferable in that the introduction efficiency into the side chain is high.

When the liquid crystal alignment agent contains a polymer having a photo-orientating group and a polymer having no photo-orientation group, the content ratio of the polymer having a photo-orientation group is determined by using the liquid crystal alignment agent. From the viewpoint of imparting sufficient orientation ability to the formed coating film by irradiation, it is preferably 1% by mass or more, preferably 5 to 99% by mass, based on the total amount of the polymer components in the liquid crystal alignment agent. It is more preferable to do so.

The polymer component contained in the liquid crystal alignment agent is not limited to the above-mentioned poly (meth) acrylate and polysiloxane, and may contain other polymers. Examples of other polymers include polyamic acid, polyimide, polyamic acid ester, polyamide, polyester, cellulose derivative, polyacetal, polystyrene derivative, poly (styrene-phenylmaleimide) derivative and the like. As the other polymer, at least one selected from the group consisting of polyamic acid and polyamic acid ester is preferable, and polyamic acid is more preferable.

The blending ratio of the other polymers is preferably 20% by mass or less, more preferably 10% by mass or less, and 5% by mass or less, based on the total amount of the polymer components in the liquid crystal alignment agent. Is more preferable. As for other polymers, one type may be used alone or two or more types may be used in combination.

(Crosslinking agent)
The liquid crystal alignment agent preferably contains a compound having a crosslinkable group (hereinafter, also referred to as a crosslinker) as another component. A crosslinkable group is a group capable of forming a covalent bond between the same or different molecules by light or heat, for example, a (meth) acryloyl group, a group having a vinyl group (alkenyl group, vinylphenyl group, etc.), an ethynyl group, Examples thereof include an epoxy group (oxylanyl group, oxetanyl group), a carboxyl group, a (protected) isocyanate group and the like. Among these, the (meth) acryloyl group is particularly preferable because of its high reactivity. In addition, "(meth) acrylo" means to include acrylo and methacrylo. The number of crosslinkable groups contained in the crosslinking agent may be one or plural. From the viewpoint of sufficiently increasing the reliability of the liquid crystal element, the number is preferably 2 or more, and more preferably 2 to 6.

Specific examples of the cross-linking agent include allyl group-containing compounds such as diallyl phthalate;
Ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, pentaerythritol tri (meth) acrylate, ditrimethylol propanetetra (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) ) (Meta) acrylic compounds such as acrylate, ethoxylated bisphenol A di (meth) acrylate, tricyclodecanedimethanol di (meth) acrylate, 2-methyl-1,8-octanediol di (meth) acrylate;
Maleic acid, itaconic acid, trimellitic acid, tetracarboxylic acid, cis-1,2,3,4-tetrahydrophthalic acid, ethylene glycol bistrimate, propylene glycol bistrimate, 4,4'-oxydiphthalic acid, trimellitic acid anhydride Carboxylic acid such as things;
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, glycerin diglycidyl ether, 2,2- Bis (4-hydroxyphenyl) propandiglycidyl ether, trimethylpropantriglycidyl ether, N, N, N', N'-tetraglycidyl-m-xylylene diamine, 1,3-bis (N, N-diglycidyl) Aminomethyl) cyclohexane, N, N, N', N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N, N-diglycidyl-benzylamine, N, N-diglycidyl-aminomethylcyclohexane, N, N-diglycidyl -Epoxy compounds such as cyclohexylamine;
Examples thereof include (protected) isocyanate compounds in which a multivalent isocyanate such as tolylene diisocyanate, hexamethylene diisocyanate, and diphenylmethylene diisocyanate is protected by a protecting group. Among these, the cross-linking agent is preferably a polyfunctional (meth) acrylate compound.

The blending ratio of the cross-linking agent is preferably 0.5 parts by mass or more with respect to 100 parts by mass of the polymer component used for preparing the liquid crystal alignment agent from the viewpoint of sufficiently obtaining the effect of improving the liquid crystal orientation and the electrical characteristics. It is more preferably 1 to 40 parts by mass, still more preferably 5 to 30 parts by mass. The cross-linking agent may be used alone or in combination of two or more.

(Antioxidant)
The liquid crystal alignment agent preferably contains an antioxidant (also referred to as a polymerization inhibitor) as another component. Antioxidants have a function of nullifying radicals and peroxides generated by energy such as ultraviolet rays and heat, and delaying or prohibiting polymerization. By containing such an antioxidant in the alignment film, the effect of suppressing the polymerization reaction of the polymerizable compound in the liquid crystal composition existing near the surface of the alignment film and suppressing the decrease in the orientation of the liquid crystal can be obtained. It is preferable in that it can be used. Specific examples of the antioxidant include, 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 antioxidant). Agent), a compound having a thioether structure (sulfur-based antioxidant), and a mixture thereof (blend-based antioxidant).

Preferred examples of antioxidants include compounds having an amine structure, such as ADEKA STUB LA-52, LA-57, LA-63, LA-68, LA-72, LA-77, LA-81, LA-81, LA-82, LA-87, LA-402, LA-502 (above, made by ADEKA), CHIMASORB119, CHIMASORB2020, CHIMASORB944, TINUVIN622, TINUVIN123, TINUVIN144, TINUVIN765, TINUVIN774, TINUVIN785, TINUVIN770, TINUVIN Etc.;
Examples of compounds having a phenolic structure include ADEKA STAB AO-20, AO-30, AO-40, AO-50, AO-60, AO-80, AO-330 (all manufactured by ADEKA), IRGANOX1010. , IRGANOX1035, IRGAOX1076, IRGANOX1098, IRGANOX1135, IRGANOX1330, IRGANOX1726, IRGANOX1425, IRGANOX1520, IRGANOX245, IRGANOX259, IRGANOX3114, IRGANOX3790, IRGANOX3114, IRGANOX3790, IRGANOX5057,

Phosphorus-based antioxidants include, for example, ADEKA STAB PEP-4C, PEP-8, PEP-36, HP-10, 2112 (above, manufactured by ADEKA), IRGAFOS168, GSY-P101 (above, manufactured by Sakai Chemical Industry Co., Ltd.), IRGAFOS168. , IRGAFOS12, IRGAFOS126, IRGAFOS38, IRGAFOS P-EPQ (above, manufactured by BASF Japan), etc.;
As sulfur-based antioxidants, for example, ADEKA STAB AO-412, AO-503 (above, manufactured by ADEKA), IRGANOX PS 800, IRGANOX PS 802 (above, manufactured by BASF Japan) and the like;
Examples of blended antioxidants include ADEKA STAB A-611, A-612, A-613, AO-37, AO-15, AO-18,328 (all manufactured by ADEKA), TINUVIN111, TINUVIN783, TINUVIN 791 (above, manufactured by BASF Japan) and the like can be mentioned respectively. As the antioxidant, one of these can be used alone or in combination of two or more.

The content ratio of the antioxidant in the liquid crystal aligning agent is preferably 0.01 to 15 parts by mass, and more preferably 0.01 to 15 parts by mass with respect to 100 parts by mass of the polymer component used for preparing the liquid crystal aligning agent. It is 10 parts by mass, and particularly preferably 0.1 to 10 parts by mass.

Other components contained in the liquid crystal alignment agent include, for example, metal chelate compounds, curing accelerators, surfactants, fillers, dispersants, photosensitizers and the like. The blending ratio of these other components can be appropriately selected according to each compound as long as the effects of the present disclosure are not impaired.

(solvent)
The liquid crystal alignment agent is prepared as a liquid composition in which the polymer component and other components used as needed are preferably dissolved in a suitable solvent.
Examples of the organic solvent used include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, γ-butyrolactone, γ-butyrolactam, N, N-dimethylformamide. , N, N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, Ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-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, diethylene 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 propionate, isoamyl isobutyrate, diisopentyl ether, ethylene carbonate, Examples thereof include propylene carbonate and the like. These can be used alone or in admixture of two or more.

The organic solvent used for preparing the liquid crystal alignment agent is one of these in order to obtain a liquid crystal alignment film showing good element characteristics even when the post-bake temperature is lowered (for example, when the temperature is 160 ° C. or lower). The compound having a boiling point of 160 ° C. or lower at atmospheric pressure is preferably contained in an amount of 40% by mass or more, more preferably 50% by mass or more, and further preferably 70% by mass or more based on the total amount of the solvent.

The solid content concentration in the liquid crystal alignment agent (the ratio of the total mass of the 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., but is preferable. It is in the range of 1 to 10% by mass. When the solid content concentration is less than 1% by mass, the film thickness of the coating film becomes too small and it becomes 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 excessive and it is difficult to obtain a good liquid crystal alignment film, and the viscosity of the liquid crystal alignment agent increases and the coatability deteriorates. There is a tendency.

<Manufacturing method of liquid crystal element>
Next, a method of manufacturing the liquid crystal element 10 will be described. The liquid crystal element 10 comprises a step A of applying a liquid crystal alignment agent to the electrode arrangement surfaces of the first base material 11 and the second base material 12 to form the liquid crystal alignment films 14 and 15, and the liquid crystal alignment films 14 and 15. A step B of constructing a liquid crystal cell by arranging a pair of base materials having the same base material so that their electrode arrangement surfaces face each other via a layer of the liquid crystal composition, and a step C of curing the polymerizable compound after constructing the liquid crystal cell. It is preferable to produce by a method including.

(Step A)
The liquid crystal alignment agent is applied on the electrode arrangement surfaces of the first base material 11 and the second base material 12, for example, offset printing method, spin coating method, roll coater method, inkjet printing method, bar coater method, flexographic printing. It is carried out by a known coating method such as a method. After the liquid crystal alignment agent is applied, preheating is preferably performed for the purpose of preventing the applied liquid crystal alignment agent from dripping. The prebake temperature is set according to the type of the base material, but is preferably 140 ° C. or lower, more preferably 120 ° C. or lower, and even more preferably 100 ° C. or lower. The lower limit of the prebake temperature is preferably 30 ° C. or higher, more preferably 40 ° C. or higher. The prebake time is preferably 0.25 to 10 minutes.

After that, it is preferable that a firing (post-baking) step is carried out for the purpose of completely removing the solvent and, if necessary, promoting the crosslinking reaction. The firing temperature (post-baking temperature) at this time is preferably 160 ° C. or lower, more preferably 150 ° C. or lower, and particularly preferably 110 ° C. or lower when a substrate made of a polymer material is used. preferable. By making at least a part of the polymer component of the liquid crystal alignment agent poly (meth) acrylate, the solubility in a low boiling point solvent can be improved, so that it is homogeneous even when the post-bake temperature is lowered. An alignment film can be obtained, and the liquid crystal orientation and voltage retention of the liquid crystal element 10 can be ensured. The post-baking time is preferably 5 to 200 minutes, more preferably 10 to 120 minutes.

(Photo-alignment treatment)
It is preferable to impart the liquid crystal alignment ability to the coating film formed by using the liquid crystal alignment agent by performing a rubbing treatment, a photoalignment treatment, or the like. In the present embodiment, a photo-alignment treatment that imparts liquid crystal alignment ability by irradiating with light is performed.

In the photoalignment treatment, the coating film can be irradiated with radiation such as ultraviolet rays including light having a wavelength of 150 to 800 nm and visible light. The radiation may be polarized or unpolarized, or may be irradiated in combination thereof. 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, a method of irradiating non-polarized light from an oblique direction, and the like.

As the light source to be 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, or the like can be used. Ultraviolet rays in a preferable wavelength region can be obtained by means of using a light source in combination with, for example, a filter or a diffraction grating. The irradiation amount of radiation is preferably 10 to 50,000 J / m ² , and more preferably 20 to 10,000 J / m ² . The light irradiation for the photoalignment treatment includes a method of irradiating the coating film after the post-baking step, a method of irradiating the coating film after the pre-baking step and before the post-baking step, a pre-baking step and a post-baking step. In at least one of the above, it can be carried out by a method of irradiating the coating film during heating or the like.

(Step B)
In step B, two base materials having a liquid crystal alignment film are prepared, and a layer of a liquid crystal composition containing a liquid crystal and a polymerizable compound is placed between the two base materials arranged so that the liquid crystal alignment films face each other. Arrange to manufacture a liquid crystal cell. Specifically, the peripheral portions of the first base material 11 and the second base material 12 are bonded together with a sealant, and the liquid crystal composition is injected and filled into the surface of the base material and the cell gap partitioned by the sealant, and then injected. Method of sealing the pores; A sealant is applied to the peripheral portion of one of the base materials on the liquid crystal alignment film side, and the liquid crystal composition is dropped onto a predetermined number of places on the liquid crystal alignment film surface, and then the liquid crystal alignment film is formed. Examples thereof include a method in which the other base material is bonded so as to face each other, the liquid crystal is spread over the entire surface of the base material, and then the sealant is cured (ODF method). As the sealing agent, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer can be used.

(Step C)
In step C, the liquid crystal composition is cured by performing one or more treatments selected from heating and light irradiation. The heating temperature at the time of the curing reaction is appropriately selected depending on the type of the polymerizable compound and the liquid crystal used, and is heated at a temperature in the range of, for example, 40 to 80 ° C. The heating time is preferably 0.5 to 5 minutes. When cured by light irradiation, unpolarized ultraviolet rays having a wavelength in the range of 200 to 500 nm can be preferably used as the irradiation light. The irradiation dose of light, preferably in the 50~10,000mJ / cm ^2, and more preferably a 100~5,000mJ / cm ^2.

The liquid crystal element 10 can be applied to various uses, for example, windows of buildings, indoor / outdoor partitions, show windows, windows of vehicles (automobiles, aircraft, ships, railroads, etc.), various indoor / outdoor advertisements. , Guidance signs, home appliances, mobile phones, smartphones, various monitors, watches, portable games, personal computers, eyeglasses, sunglasses, medical equipment, furniture, etc. can be effectively used as various dimming elements. The liquid crystal element 10 may be used as it is, or may be attached to glass, a transparent resin, or the like, depending on the thickness, hardness, shape, application, and the like of the element.

(Liquid crystal device)
The display device of the present disclosure includes the above-mentioned liquid crystal element and a transparent display that becomes 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, and the liquid crystal element 10 functions as a dimming element to be transparent. The visibility of the display on the display 30 changes.

The transparent display 30 is, for example, an organic electroluminescence element (organic EL element), and is formed between a pair of glass substrates, an anode electrode and a cathode electrode made of a transparent electrode material, and an anode electrode and a cathode electrode. It includes a hole transport layer and a light emitting layer. The entire surface of the transparent display 30 is transparent when no voltage is applied, and when the voltage is applied, the pixels to which the voltage is applied emit light, and characters, images, and the like are displayed.

In the display device 20 of FIG. 3, when the liquid crystal element 10 and the transparent display 30 are in a state where no voltage is applied, the entire surface of the display device 20 becomes transparent. Therefore, for example, when the display device 20 is applied as the front glass or the rear glass of the show window, it is possible to visually recognize the products displayed in the showcase and the inside of the store from the outside. Further, by applying a voltage to the transparent display 30 while the liquid crystal element 10 is in a state where no voltage is applied, characters, images, and the like displayed on the transparent display 30 are displayed in a state of being raised on the glass. Become.

On the other hand, when 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, and the like displayed on the display device 20 can be prevented from overlapping with the object behind the display device 20, and the display on the transparent display 30 becomes easier to see. In addition, the decorativeness can be enhanced. Alternatively, the degree of light transmission from the front surface to the back surface of the display device 20 may be made variable by controlling the applied voltage of the liquid crystal element 10 according to the brightness of the front surface and the back surface of the display device 20. ..

In the display device 20 of FIG. 3, the dimming element 10 may be arranged only in a part of the transparent display 30. Alternatively, the transmittance may be changed for each display area by dividing the display area of the transparent display 30 into a plurality of display areas and arranging dimming elements for each display area.

In the above embodiment, the liquid crystal alignment films 14 and 15 are used as photo-alignment films, but the photo-alignment treatment may not be performed. Also in this case, when a base material made of a polymer material is used as the base material of the liquid crystal element 10, the liquid crystal alignment film is homogeneous, the transparency of the liquid crystal alignment film is high, and the light transmission characteristics and the light scattering characteristics are exhibited. It is possible to obtain a liquid crystal element which is good in quality, exhibits sufficient electrical characteristics for realizing a dimming function, and has excellent weather resistance.

Hereinafter, the content of the present disclosure will be described in more detail with reference to Examples, but the content of the present disclosure is not limited to these Examples.

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

[Weight average molecular weight Mw and number average molecular weight Mn of polymer]
Mw and Mn are polystyrene-equivalent values measured by GPC under the following conditions.
Column: Made by Tosoh Corporation, TSKgelGRCXLII
Solvent: tetrahydrofuran Temperature: 40 ° C
Pressure: 68 kgf / cm ²
[Epoxy equivalent]
The epoxy equivalent was measured by the hydrochloric acid-methylethylketone method described in JIS C 2105.
[Solution viscosity of polymer solution]
The solution viscosity (mPa · s) of the polymer solution was measured at 25 ° C. using an E-type rotational viscometer.

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

(carboxylic acid)

(Polymerizable compound)

(Light initiator)

(Crosslinking agent)

(Silane compound)

(Antioxidant)

(Dichroic pigment)

<Synthesis of poly (meth) acrylate>
[Synthesis Example 1]
A flask equipped with a cooling tube and a stirrer was charged with 1.2 parts by mass of 2,2'-azobisisobutyronitrile and 200 parts by mass of propylene glycol monomethyl ether acetate. Subsequently, 80 parts by mass of glycidyl methacrylate and 20 parts by mass of styrene were charged, and after nitrogen substitution, gentle stirring was started. The solution temperature was raised to 95 ° C. and maintained at this temperature for 5 hours to obtain a polymer solution containing a polymer (Pac-1). The monomer consumption rate after completion of the reaction calculated from the measurement result of the solid content concentration of the polymer solution was 99%.

[Synthesis Example 2]
A flask equipped with a cooling tube and a stirrer was charged with 1.2 parts by mass of 2,2'-azobisisobutyronitrile and 200 parts by mass of propylene glycol monomethyl ether acetate. Subsequently, 50 parts by mass of glycidyl methacrylate and 50 parts by mass of tricyclo [5.2.1.0 ^2,6 ] deca-8-yl = methacrylic acid were charged, and after nitrogen substitution, gentle stirring was started. The solution temperature was raised to 95 ° C. and maintained at this temperature for 5 hours to obtain a polymer solution containing a polymer (Pac-2). The monomer consumption rate after 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]
In a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser, 100.0 g of 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (ECETS), 500 g of methyl isobutyl ketone and 10.0 g of triethylamine were placed. It was charged and mixed at room temperature. Then, 100 g of deionized water was added dropwise from the dropping funnel over 30 minutes, and then the mixture was reacted at 80 ° C. for 6 hours while mixing under reflux. After completion of the reaction, the organic layer was taken out, washed with a 0.2 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 a polysiloxane having an epoxy group. Was obtained as a viscous transparent liquid. ^{When 1} H-NMR analysis was performed on this polysiloxane having an epoxy group, a peak based on the epoxy group was obtained near chemical shift (δ) = 3.2 ppm, and a side reaction of the epoxy group occurred during the reaction. It was confirmed that there was no such thing. The weight average molecular weight (Mw) of the epoxy group-bearing polysiloxane (SEp-1) obtained in Synthesis Example 3 was Mw = 2,200, and the epoxy equivalent was 186 g / mol.

<Synthesis of polysiloxane with functional groups>
[Synthesis Example 4]
In a 100 mL three-necked flask, 18.4 g of polysiloxane (SEp-1) having an epoxy group obtained in Synthesis Example 3, 70.8 g of methylisobutylketone, and 3.45 g of cinnamic acid derivative (CA-1) (polyorganosiloxane (polyorganosiloxane). (15 mol parts with respect to 100 mol parts of the epoxy group contained in SEp-1), 6.21 g of the cinnamic acid derivative (CA-2) (25 mol with respect to 100 mol parts of the epoxy group contained in the polysiloxane (SEp-1)). Part) and 1.03 g of tetrabutylammonium bromide were charged and stirred at 80 ° C. for 12 hours. After completion of the reaction, 40 g of diethylene glycol diethyl ether and 60 g of cyclohexane were added, and this solution was washed with water by 6 times liquid separation washing, then another 100 g of diethylene glycol diethyl ether was added, and the solvent was distilled off so that the solid content concentration became 10% by mass. did. As a result, a diethylene glycol diethyl ether solution containing a polymer (S-1) which is a polysiloxane having a functional group and having 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 polymer (S-2), (S) was synthesized in the same manner as in Synthesis Example 4 except that the type and amount of the carboxylic acid used in the reaction were changed as shown in Table 1 below, and used as a polysiloxane having a functional group. -3) was obtained. The numbers in Table 1 represent the number of moles of the polysiloxane (SEp-1) with respect to 100 moles of the epoxy group.

<Synthesis of polyamic acid>
[Synthesis Example 7]
121.35 g of tetracarboxylic dianhydride 2,3,5-tricarboxycyclopentylacetic acid dianhydride (90 mol parts relative to 100 mol parts of the total amount of diamine used in the synthesis), and 3,5 diamine compounds 94.34 g (30 mol parts) of cholestanyl-diaminobenzoate and 84.3 g (70 mol parts) of 4,4'-diaminodiphenyl ether were dissolved in 1200 g of N-methyl-2-pyrrolidone (NMP) at 30 ° C. The reaction was carried out for 6 hours. The reaction mixture was then poured into a large excess of methanol to precipitate the reaction product. The recovered precipitate was washed with methanol and then dried under reduced pressure at 40 ° C. for 15 hours to obtain 290 g of polyamic acid (hereinafter referred to as polymer (PA-1)). The obtained polymer (PA-1) was prepared by NMP so as to be 20% by mass, and the viscosity of this solution was measured and found to be 1310 mPa · s. Further, when this polymer solution was allowed to stand at 20 ° C. for 3 days, it did not gel and the storage stability was good.

<Synthesis of polyimide>
[Synthesis Example 8]
2,4,6,8-Tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-dianhydride as tetracarboxylic dianhydride 3.19 g (12.8 mmol), and diamine compound As 1,3-diamino-4- [4- (trans-4-n-heptylcyclohexyl) phenoxymethyl] benzene 4.59 g (11.6 mmol) and 3,5-diaminobenzoic acid 2.16 g (14.2 mmol). Was dissolved in 24.9 g of NMP and reacted at 80 ° C. for 5 hours. Then, as tetracarboxylic dianhydride, 2.50 g (12.8 mmol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride, And 12.4 g of NMP were added, and the reaction was carried out at 40 ° C. for 8 hours to obtain a polyamic acid solution having a polymer concentration of 25% by mass. NMP was added to 30.0 g of the obtained polyamic acid solution to dilute it to 6% by mass, then 3.95 g of acetic anhydride and 2.40 g of pyridine were added, and the mixture was reacted at 50 ° C. for 2 hours. The reaction mixture was then poured into a large excess of methanol to precipitate the reaction product. The recovered precipitate was washed with methanol and then dried under reduced pressure at 100 ° C. to obtain a polyimide (hereinafter referred to as a polymer (PI-1)). The imidization ratio of the obtained polyimide was 55%, and the weight average molecular weight was 48,000.

<Preparation of liquid crystal composition>
1. 1. Preparation of liquid crystal composition I 1.20 g of liquid crystal (MLC-6608, manufactured by Merck), 1.20 g of compound (R-1) as a polymerizable compound, 0.60 g of compound (R-2), and compound (R). -3) 0.12 g, compound (R-4) 0.36 g, and compound (P-1) 0.012 g as a photoinitiator are mixed, heated, and then cooled to 25 ° C. to form a liquid crystal. Composition I was obtained.
2. Preparation of Liquid Crystal Composition II 1.20 g of liquid crystal (MLC-6608, manufactured by Merck), 0.024 g of the bicolor dye shown below, 1.20 g of compound (R-1) as a polymerizable compound, compound ( A mixture of 0.60 g of R-2), 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. After heating, the mixture was 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 the polymer (S-1) obtained in Synthesis Example 4 is converted into a polymer (S-1) in an amount corresponding to 20 parts by mass, and Synthesis Example 1 The solution containing the polymer (PAc-1) obtained in the above was mixed in an amount corresponding to 80 parts by mass in terms of the polymer (PAc-1) and 5 parts by mass of the compound (add-2). Propylene glycol monomethyl ether (PGME), diethylene glycol diethyl ether (DEDG), and propylene glycol monomethyl ether acetate (PGMEA) were added as solvents, the solid content concentration was 4% by mass, and the weight ratio of each solvent was PGME: DEDG: PGMEA =. It was prepared to be 30:20:50. Then, the obtained solution was filtered through a filter having a pore size of 0.2 μm to prepare a liquid crystal alignment agent (A-1).

<Evaluation of liquid crystal alignment agent and liquid crystal element>
1. 1. Evaluation of coatability The liquid crystal alignment agent (A-1) prepared above is applied to the electrode arrangement surface of a PET film base material (PET-ITO base material) having an ITO electrode on the surface of the base material using a bar coater. Then, after prebaking for 1 minute on a hot plate at 80 ° C., the inside of the chamber was heated (post-baked) for 2 minutes in an oven at 120 ° C. in which nitrogen was substituted to form a coating film having an average thickness of 0.1 μm. .. This coating film was visually observed and observed with a microscope at a magnification of 100 times to check for uneven film thickness, uneven coating, and the presence or absence of pinholes. The evaluation was "good" when no film thickness unevenness, coating unevenness, or pinholes were observed even when visually observed or observed with a 100x microscope, and pinholes were observed with a 100x microscope. However, when coating unevenness on the coating film surface is not visually observed, the coating property is "possible", and when at least one of film thickness unevenness, coating unevenness, and pinholes is clearly observed. The coatability was "poor". In this example, no film thickness unevenness, coating unevenness, or pinhole was observed by visual inspection or a 100x microscope, and the coating property was "good".

2. Evaluation of coating film transparency Above 1. The transparency of the coating film was evaluated by the light transmittance (%) at a wavelength of 400 nm using a spectrophotometer (150-20 type double beam manufactured by Hitachi, Ltd.). In the evaluation, the transparency was "good" when the light transmittance was 97% or more, and the transparency was "poor" when the light transmittance was less than 97%. As a result, the light transmittance of this coating film was 98.1%, and the transparency was "good".

3. 3. Manufacture of liquid crystal elements 1. A liquid crystal alignment film is formed by irradiating the surface of the coating film prepared in (1) with polarized ultraviolet light of 20 mJ / cm ² containing a bright line of 313 nm from a direction inclined by 20 ° from the normal of the substrate by using an Hg-Xe lamp and a Gran Tailor prism. Obtained. The same operation was repeated to prepare a pair (two sheets) of substrates having a liquid crystal alignment film. Next, a 6 μm spacer was applied to the surface of one of the base materials having the liquid crystal alignment film, and then the liquid crystal composition I prepared above was added dropwise to the surface of the liquid crystal alignment film to which the spacer was applied. Next, the two base materials were bonded together with a sealant so that the liquid crystal alignment film surfaces of the other base material faced each other to obtain a liquid crystal cell. ^{This liquid crystal cell is irradiated with ultraviolet rays under the conditions of a wavelength of 365 nm, an ultraviolet intensity of 15 mW / cm 2} , an irradiation time of 15 seconds, and a substrate surface temperature of 20 ° C. using an ultraviolet irradiation device using an ultraviolet light emitting diode as a light source to form a liquid crystal composition. The object I was cured to obtain the liquid crystal element 10 shown in FIG.

4. Evaluation of Light Transparency The transparency when no voltage was applied was evaluated by measuring the haze (HAZE) of the liquid crystal element when 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 was 2%, and the transparency was excellent in the state where no voltage was applied.
5. Evaluation of light scattering property The light scattering property when a voltage was applied was evaluated by measuring the (HAZE) of the liquid crystal element when a voltage was applied. The measurement is performed in 3. above. 20V is applied to the liquid crystal element manufactured in the above 4. The same procedure was performed using a spectroscopic haze meter (manufactured by Tokyo Denshoku Co., Ltd.). The higher the haze value, the better the light scattering property. As a result, in this example, the haze value was 92%, and the light scattering property in the voltage-applied state was excellent.

6. Evaluation of voltage retention rate 3. After applying a voltage of 5 V at 23 ° C. for an application time of 60 microseconds and a span of 167 ms, the voltage retention rate (VHR _BF ) was measured 1670 ms after the application was released. However, the voltage holding ratio was 80.4%. As the measuring device, VHR-1 manufactured by Toyo Technica Co., Ltd. was used.

7. Evaluation of weather resistance 3. ^{The liquid crystal element manufactured in 1 was irradiated with xenon lamp light (illuminance 250 W / m 2} (300-800 nm)) for 200 hours by a light resistance tester (SUNTEST CPS +: manufactured by Toyo Seiki Co., Ltd.). Regarding the liquid crystal element after light irradiation, the above 6. The voltage retention rate was measured by the same method as in. This value was taken as the voltage retention rate (VHR _AFXe ) after light irradiation. The reduction rate ΔVHR _Xe (%) of the voltage holding rate was obtained from the following mathematical formula (EX-1), and the weather resistance was evaluated based on the _{reduction rate ΔVHR Xe.}
ΔVHR _Xe = ((VHR _BF −VHR _AFXe ) ÷ VHR _BF ) × 100 ... (EX-1)
When ΔVHR _Xe was less than 5%, it was judged as “good”, when it was 5% or more and less than 10%, it was judged as “possible”, and when it was 10% or more, it was judged as “poor”. _{As a result, the ΔVHR Xe} of the liquid crystal element of this example was 3.5%, and the weather resistance was “good”.
Further, regarding the liquid crystal element after being irradiated with light for 200 hours, the above 4. The haze value in the state where no voltage was applied was measured by the same method as in the above, and the weather resistance was evaluated based on the haze value. As a result, in the liquid crystal element of this example, the haze value was 2% even after the light irradiation, and the transparency did not change before and after the light irradiation.

[Examples 2 to 7 and Comparative Example 1]
Except for the fact that each component of the type and blending amount shown in Table 2 below was used, the same procedure as for the preparation of the liquid crystal alignment agent (A-1) was carried out, and each liquid crystal alignment agent (A-2) to (A-8) was prepared. Prepared. In addition, the liquid crystal elements were evaluated in the same manner as in Example 1 using the liquid crystal alignment agents (A-2) to (A-8). The results are shown in Table 3 below.

[Example 8]
1. 1. Production and Evaluation of Liquid Crystal Device A liquid crystal device was manufactured in the same manner as in Example 1 except that the liquid crystal composition II was used instead of the liquid crystal composition I. Moreover, the same evaluation as in Example 1 was performed using the obtained liquid crystal element. The results are shown in Table 3 below.

In Example 8, the above 1. Using the liquid crystal element manufactured in (1), the following evaluations (evaluation of light transmission, evaluation of light blocking property, 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 when no voltage was applied. For the measurement, a spectrophotometer (150-20 type double beam manufactured by Hitachi, Ltd.) was used, 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, in this example, the transmittance was 93%, and the transparency was excellent in the state where no voltage was applied.
3. 3. Evaluation of light blocking property The light blocking property when voltage was applied was evaluated by measuring the transmittance of the liquid crystal element when voltage was applied. The measurement is as described in 1. above. 40V was applied by AC drive to the liquid crystal element manufactured in 2. above. The same procedure was performed using a spectrophotometer (150-20 type double beam manufactured by Hitachi, Ltd.). The lower the transmittance value, the better the light blocking property. As a result, in this example, the transmittance was 5%, and the light blocking 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 then no application was applied for 1 second. After repeating this operation 1800 times, the above 2. And the above 3. The repeated drive durability test was evaluated by evaluating the light transmittance and the light blocking property in the same manner as in the above. As a result, in this embodiment, the transmittance when no voltage is applied = 93% and the transmittance when a voltage is applied = 7%, and no change in the transmittance is observed before and after driving when no voltage is applied. When the voltage was applied, the increase in transmittance was only 2%. From this result, it can be said that the liquid crystal element of this embodiment is excellent in repeat drive durability.

The numerical value of the blending amount in Table 2 shows the blending ratio (parts by mass) of each compound with respect to the total 100 parts by mass of the polymer components used for preparing the liquid crystal alignment agent.
In Table 2, the abbreviations are as follows: PGME: Propylene Glycol Monomethyl Ether PGMEA: Propylene Glycol Monomethyl Ether Acetate DEDG: Diethylene Glycol Diethyl Ether NMP: N-Methyl-2-pyrrolidone GBL; γ-Butyrolactone

As can be seen from Table 3, the liquid crystal alignment film containing the poly (meth) acrylate is homogeneous and highly transparent even when the post-baking temperature is low (120 ° C.), and the light transmission characteristics of the liquid crystal element are high. And the light scattering characteristics were good. In addition, the obtained liquid crystal element had a sufficiently high voltage holding ratio and good weather resistance. In particular, Examples 1 and 2 containing poly (meth) acrylate and polysiloxane in the liquid crystal alignment film and having a high ratio of poly (meth) acrylate have coatability, light transmittance, light scattering property, electrical characteristics and weather resistance. The sex was particularly excellent. Further, in Example 7 in which the liquid crystal alignment film contains an antioxidant, in the obtained liquid crystal element, the haze value when no voltage is applied and the haze value after weather resistance evaluation determine the antioxidant in the liquid crystal alignment film. It was superior to Example 4 which did not include it.
Further, also in Example 8 in which the dye (dichroic dye) was dispersed in the liquid crystal layer, the voltage retention rate of the obtained liquid crystal element was sufficiently high and the weather resistance was also good. Further, even after the liquid crystal element was repeatedly applied with / without voltage, both the light shielding property and the light transmissive property were good, and the driving durability was excellent. This behavior is considered to be due to the assist from the alignment film side.
On the other hand, Comparative Example 1 in which the liquid crystal alignment film made of polyimide was inferior to the examples in the coatability and transmittance of the coating film and the light transmittance and weather resistance (haze value) of the liquid crystal element.

<Display test when combined with a transparent display>
[Example 9]
A display device in which the liquid crystal element manufactured in Example 2 was superposed on one outer surface of the transparent display was produced, and the transparent display was displayed. As a result, the transparency was good when no voltage was applied to the liquid crystal element. , The visibility of the display on the transparent display was judged to be "good".

[Comparative Example 2]
A display test was carried out in the same manner as in Example 9 except that a polarizing plate type liquid crystal element was used instead of the liquid crystal element of Example 9. As a polarizing plate type liquid crystal element, a transparent electrode and a liquid crystal alignment film are formed on each of the facing surfaces of a pair of glass substrates, a liquid crystal is filled between the pair of substrates, and a sealant is arranged around the liquid crystal. A cell having a polarizing plate arranged on the outside of the glass substrate was used. As a result, in Comparative Example 2, the light transmittance of the liquid crystal element was poor, and the visibility of the display on the transparent display was judged to be "poor". This can be said to indicate that the light transmission of the PDLC element using the acrylic resin is good. On the other hand, in the polarizing plate type liquid crystal element, since the polarizing plate absorbs light, the transmittance is theoretically not 50% or more, and the visibility of the transparent display is inferior. From the above, it can be said that the liquid crystal element 10 having a liquid crystal alignment film containing a poly (meth) acrylate is particularly excellent as a display element to be superimposed on the transparent display.

Although the present disclosure has been described in accordance with the embodiments, it is understood that the present disclosure is not limited to the above embodiments and structures. The present disclosure also includes various modifications and modifications within an equal range. In addition, various combinations and forms, as well as other combinations and forms that include only one element, more, or less, are also within the scope of the present disclosure.

10 ... liquid crystal element, 11 ... first base material, 12 ... second base material, 13 ... liquid crystal layer, 14, 15 ... liquid crystal alignment film, 16, 17 ... transparent electrode, 20 ... display device, 30 ... transparent display

Claims (14)

A pair of base materials arranged facing each other,
Electrodes arranged on the surfaces facing each other in the pair of base materials, and
A liquid crystal layer arranged between the pair of substrates and formed by curing a liquid crystal composition containing a liquid crystal and a polymerizable compound.
A liquid crystal element including a liquid crystal alignment film formed on at least one electrode arrangement surface of the pair of base materials.
The liquid crystal composition contains a monofunctional (meth) acrylate compound and a polyfunctional (meth) acrylate compound as the polymerizable compound.
The liquid crystal layer is a polymer-dispersed liquid crystal layer in which a polymer obtained by polymerizing the polymerizable compound and the liquid crystal are mixed in the layer.
The liquid crystal element does not have a polarizing plate, and is in a transmissive state in which light is transmitted when a voltage is not applied between the electrodes, and does not scatter light when a voltage is applied between the electrodes. It becomes transparent and becomes transparent
The liquid crystal alignment film, Ri Na is formed by a liquid crystal aligning agent containing a poly (meth) acrylate,
The poly (meth) acrylate is a polymer obtained by using a (meth) acrylic monomer having an epoxy group in an amount of 1% by mass or more based on the total amount of the monomers used for the polymerization. .. The liquid crystal element according to claim 1, wherein the content ratio of the poly (meth) acrylate in the liquid crystal alignment agent is 3 to 99% by mass with respect to the total amount of the polymer components contained in the liquid crystal alignment agent. The liquid crystal element according to claim 1 or 2, wherein the liquid crystal alignment agent further contains polysiloxane. The liquid crystal element according to any one of claims 1 to 3, wherein the liquid crystal aligning agent contains a polymer having a photoaligning group. The liquid crystal element according to any one of claims 1 to 4, wherein the liquid crystal alignment agent further contains a silane compound. The liquid crystal element according to any one of claims 1 to 5, wherein the liquid crystal aligning agent further contains a compound having a crosslinkable group. The liquid crystal element according to any one of claims 1 to 6, wherein the liquid crystal composition further contains a dye. The liquid crystal device according to claim 7, wherein the dye is at least one selected from the group consisting of an azo compound and an anthraquinone compound. The liquid crystal element according to any one of claims 1 to 8, wherein the liquid crystal composition further contains an antioxidant. A display device comprising the liquid crystal element according to any one of claims 1 to 9 and a transparent display that becomes transparent in a non-display state. The liquid crystal composition comprises a pair of base materials arranged so that electrodes provided on each base material surface face each other, and a liquid crystal layer formed by curing a liquid crystal composition containing a liquid crystal and a polymerizable compound. Contains a monofunctional (meth) acrylate compound and a polyfunctional (meth) acrylate compound as the polymerizable compound, and the liquid crystal layer is a polymer dispersion in which a polymer obtained by polymerizing the polymerizable compound and the liquid crystal are mixed in the layer. A type liquid crystal layer, which is a transmissive state in which light is transmitted when no voltage is applied between the electrodes, and is in a non-transmissive state in which light is scattered when a voltage is applied between the electrodes. It is a liquid crystal alignment agent for forming a liquid crystal alignment film of a liquid crystal element that does not have the above.
Contains poly (meth) acrylate ,
Wherein the poly (meth) acrylates, having an epoxy group and (meth) acrylic monomer, Ru polymer der obtained by using 1 wt% or more based on the total amount of the monomers used in the polymerization, the liquid crystal Aligning agent. A method for producing a liquid crystal element, which comprises a liquid crystal layer formed by curing a liquid crystal composition containing a liquid crystal and a polymerizable compound between a pair of base materials arranged so that electrodes provided on each base material surface face each other. And
A step of applying a liquid crystal alignment agent on at least one electrode arrangement surface of the pair of base materials to form a liquid crystal alignment film, and a step of forming a liquid crystal alignment film.
A step of constructing a liquid crystal cell by arranging the pair of base materials so that the electrodes face each other via a layer containing the liquid crystal composition after forming the liquid crystal alignment film.
A step of curing the polymerizable compound after the construction of the liquid crystal cell is included.
The liquid crystal composition contains a monofunctional (meth) acrylate compound and a polyfunctional (meth) acrylate compound as the polymerizable compound.
The liquid crystal layer is a polymer-dispersed liquid crystal layer in which a polymer obtained by polymerizing the polymerizable compound and the liquid crystal are mixed in the layer.
The liquid crystal element does not have a polarizing plate, and is in a transmissive state in which light is transmitted when a voltage is not applied between the electrodes, and does not scatter light when a voltage is applied between the electrodes. It becomes transparent and becomes transparent
The liquid crystal alignment agent contains a poly (meth) acrylate and contains .
The poly (meth) acrylate is a polymer obtained by using a (meth) acrylic monomer having an epoxy group in an amount of 1% by mass or more based on the total amount of the monomers used for the polymerization. Manufacturing method. The method for manufacturing a liquid crystal element according to claim 12, wherein the liquid crystal alignment agent applied on the electrode arrangement surface is heated at 160 ° C. or lower. The claim that the liquid crystal alignment agent is applied on at least one electrode arrangement surface of the pair of base materials to form a coating film, and the coating film is irradiated with light to impart a liquid crystal alignment ability to the coating film. The method for manufacturing a liquid crystal element according to 12 or 13.

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