Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal element

Abstract

A liquid crystal alignment agent containing the following (A) component, (B) component, and (C) component. (A) component: at least one polymer (A) selected from the group consisting of a polymer (A-1) of a monomer (a-1) having a polymerizable unsaturated bond, a polyimide precursor (A-2) having a carboxyl group, and a polyimide (A-3) having a carboxyl group, wherein the polymer (A-1) has a carboxyl group. (B) component: a compound (B) having two or more epoxy groups in a molecule and having a molecular weight of 2000 or less. (C) component: a compound (C) having at least one carboxyl group and one polymerizable unsaturated bond in a molecule and having at least one group selected from the group consisting of an alkylene group, an alicyclic hydrocarbon group having 4 to 40 carbon atoms, and an aromatic hydrocarbon group having 6 to 40 carbon atoms, and having a molecular weight of 2000 or less.

Description

Technical Field

[0001] This invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, a liquid crystal element, a polymer-dispersed liquid crystal element, and a method for manufacturing the same. Background Technology

[0002] Polymer-dispersed liquid crystal elements do not require polarizers, and therefore have the advantage of achieving brighter displays compared to conventional liquid crystal display elements that use polarizers, such as TN (Twisted Nematic), STN (Super Twisted Nematic), IPS (In-Plane Switching), or VA (Vertical Alignment) modes. The elements are also simpler in structure, making them suitable for applications such as optical shutters in dimming glass and segmented displays in clocks and watches.

[0003] Among these polymer-dispersed liquid crystal elements, there are several types, such as the type called NCAP (Nematic Curvilinear Aligned Phase) (Patent Document 1), the type called PDLC (Polymer Dispersed Liquid Crystal) (Patent Document 2, Patent Document 3), the type called PNLC (Polymer Network Liquid Crystal) (Patent Document 4), and the polymer-stabilized cholesteric texture (PSCT) which uses cholesteric liquid crystal.

[0004] Among them, liquid crystal elements using PDLC and PNLC were actively studied. It is known that: conventional mode type polymer dispersion liquid crystal element (Patent Document 5) is in a cloudy (light scattering) state when no voltage is applied, and the liquid crystal is aligned along the electric field direction when a voltage is applied, and becomes a transmission state; reverse mode type polymer dispersion liquid crystal element (Patent Document 6) is in a transmission state when no voltage is applied, and becomes a scattering state when a voltage is applied.

[0005] In dimming applications, dimming elements with the following structure have been studied: a polymer liquid crystal layer consisting of polymer encapsulating liquid crystal molecules is used as the dimming layer, and the dimming layer is sandwiched from both sides by a pair of glass or plastic substrates with transparent electrodes formed by transparent conductive films. Sometimes, a liquid crystal alignment film for aligning liquid crystal molecules is also formed on the surface of the transparent electrodes.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Publication No. 58-501631

[0009] Patent Document 2: Japanese Patent Application Publication No. 2-15236

[0010] Patent Document 3: Japanese Patent Application Publication No. 63-271233

[0011] Patent Document 4: Japanese Patent Application Publication No. 1-198725

[0012] Patent Document 5: WO2020 / 184420

[0013] Patent Document 6: WO2014 / 133154 Summary of the Invention

[0014] The problem that the invention aims to solve

[0015] In recent years, regarding dimming elements that use the aforementioned polymer liquid crystal layers, based on their high light transmittance, applications such as sunroofs for automobiles, shop windows that can display text and patterns, and smart windows that can expect infrared blocking effects have been studied.

[0016] In the applications described above, the field of view needs to be blocked in the light-scattering state, while a sufficient field of view needs to be ensured in the transmission state. Therefore, in dimming elements using PDLC and PNLC, it is required to maximize the light transmittance in the transmission state as much as possible than ever before.

[0017] Furthermore, if the adhesion between the polymer liquid crystal layer and the substrate in the dimming element is low, the light scattering will change over time and may lose its function of blocking the field of view. Therefore, an alignment film with high adhesion between the polymer liquid crystal layer and the substrate is required.

[0018] The present invention was made to solve the above-mentioned problems, and provides a liquid crystal alignment agent, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal element and a polymer-dispersed liquid crystal element having the liquid crystal alignment film. The liquid crystal alignment agent provides a liquid crystal alignment film with high light transmittance in the transmission state and high adhesion between the polymer liquid crystal layer and the substrate.

[0019] Solution for solving the problem

[0020] In order to solve the above-mentioned problems, the inventors conducted in-depth research and found that a liquid crystal alignment agent containing the following composition is effective in achieving the above-mentioned objectives, thereby completing the present invention.

[0021] The present invention is based on the following content.

[0022] A liquid crystal alignment agent, characterized in that it contains the following components (A), (B) and (C).

[0023] (A) Component: At least one polymer (A) selected from the group consisting of a polymer (A-1) of a monomer having a polymerizable unsaturated bond, a polyimide precursor having a carboxyl group (A-2), and a polyimide having a carboxyl group (A-3), wherein the polymer (A-1) has a carboxyl group.

[0024] (B) Component: Compounds with two or more epoxy groups in the molecule and a molecular weight of less than 2000 (B).

[0025] (C) Composition: A compound with a molecular weight of less than 2000 that has at least one carboxyl group and one polymerizable unsaturated bond in the molecule and has at least one group selected from the group consisting of alkylene, alicyclic hydrocarbon groups with 4 to 40 carbon atoms and aromatic hydrocarbon groups with 6 to 40 carbon atoms.

[0026] It should be noted that, in this invention, halogen atoms can include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc., and * indicates a bond.

[0027] Invention Effects

[0028] According to the present invention, a liquid crystal alignment agent, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal element and a polymer-dispersed liquid crystal element having the liquid crystal alignment film can be obtained. The liquid crystal alignment agent provides a liquid crystal alignment film with high transmittance in the transmission state and high adhesion between the polymer liquid crystal layer and the substrate. Attached Figure Description

[0029] Figure 1 This is a schematic cross-sectional view showing an example of a liquid crystal element. Detailed Implementation

[0030] Hereinafter, the liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal element having the liquid crystal alignment film of the present invention will be described in detail. The description of the necessary conditions for the construction described below is an example of one embodiment of the present invention and is not specific to these contents.

[0031] <(A)Component>

[0032] The liquid crystal alignment agent of the present invention contains the above-mentioned component (A). It should be noted that the polymer (A) contained in component (A) may be one type or two or more types.

[0033] (A) The component is at least one polymer (A) selected from the group consisting of (A-1) to (A-3) below.

[0034] (A-1): A polymer of monomers with polymerizable unsaturated bonds, wherein the monomer has a carboxyl group.

[0035] (A-2): A polyimide precursor with a carboxyl group.

[0036] (A-3): Polyimide with a carboxyl group.

[0037] Component (A) contains carboxyl groups, thus undergoing a crosslinking reaction with the epoxy groups present in component (B). Furthermore, since component (A) is a polymer and contains carboxyl groups, it exhibits high orientation towards the substrate, and a liquid crystal alignment film with high adhesion to the substrate is expected. Moreover, when component (A) contains orientation functional groups (e.g., the monovalent group "J" in the group "-X-J" described later), the hydrophobicity of the liquid crystal alignment agent increases, potentially leading to coating defects such as striations and edge shrinkage. By introducing carboxyl groups into component (A), the hydrophobicity of the liquid crystal alignment agent can be adjusted, suppressing the occurrence of these coating defects.

[0038] (Polymer (A-1))

[0039] The polymer (A-1) has a carboxyl group.

[0040] Polymer (A-1) is a polymer of monomer (a-1) with polymerizable unsaturated bonds.

[0041] Examples of monomers (a-1) possessing polymerizable unsaturated bonds include: (meth)acrylic acid compounds (including unsaturated carboxylic acids, unsaturated carboxylic esters, and unsaturated polycarboxylic anhydrides), (meth)acrylamide compounds, aromatic vinyl compounds, conjugated diene compounds, compounds containing maleimide groups, α-methylene-γ-butyrolactone compounds, and vinyl compounds. From the viewpoints of transparency and material strength, polymer (A-1) is preferably a polymer containing monomer components of the (meth)acrylic acid compounds mentioned above. When synthesizing polymer (A-1), the proportion of the (meth)acrylic acid compounds used relative to the total amount of monomers used in the synthesis is preferably set to 50 mol% or more, and more preferably 60 mol% or more.

[0042] The monomer (a-1) with polymerizable unsaturated bonds mentioned above can be used alone or in combination of two or more monomers. That is, the polymer (A-1) can be a homopolymer of a monomer equivalent to monomer (a-1) or a copolymer of two or more monomers equivalent to monomer (a-1).

[0043] The target polymer (A-1) can be obtained, for example, by a method based on polymerization using a monomer having a carboxyl group and a polymerizable unsaturated bond; or by (i) synthesizing a polymer having an epoxy group in the side chain by using a monomer having an epoxy group and a polymerizable unsaturated bond in at least a portion of the raw material for polymerization, and (ii) then reacting the resulting polymer having an epoxy group in the side chain with a carboxylic acid having two or more carboxyl groups.

[0044] Specific examples of the monomers having carboxyl groups and polymerizable unsaturated bonds mentioned above include, for example, the compound shown in compound (C) above (the compound equivalent to component (C)), or compounds having two or more carboxyl groups such as itaconic acid, maleic acid, or fumaric acid.

[0045] As monomers that can be used to synthesize polymer (A-1), monomers with polymerizable unsaturated bonds other than those with carboxyl groups and polymerizable unsaturated bonds (hereinafter also referred to as other monomers with polymerizable unsaturated bonds) can also be used. The following monomers can be listed as other monomers with polymerizable unsaturated bonds.

[0046] Compounds represented by the following formula (S-mA) (excluding the monomers having carboxyl groups and polymerizable unsaturated bonds mentioned above); amino-containing (meth)acrylate compounds such as aminoethyl (meth)acrylate and aminopropyl (meth)acrylate; (meth)acrylamide compounds containing hydroxymethyl or alkoxymethyl groups such as N-hydroxymethyl (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-ethoxymethyl (meth)acrylamide, and N-butoxymethyl (meth)acrylamide; allyl glycidyl ether, glycidyl acrylate, and glycidyl methacrylate. 2-Methyl glycidyl methacrylate, α-ethyl glycidyl acrylate, α-n-propyl glycidyl acrylate, α-n-butyl glycidyl acrylate, 3,4-epoxybutyl acrylate, 3,4-epoxybutyl methacrylate, 6,7-epoxyheptyl acrylate, 6,7-epoxyheptyl methacrylate, α-ethyl acrylate-6,7-epoxyheptyl acrylate, o-vinyl benzyl glycidyl ether, m-vinyl benzyl glycidyl ether, p-vinyl benzyl glycidyl ether, 3,4-epoxycyclohexyl methyl methacrylate, 3-vinyl-7-oxabicyclo[4.1].[0] Compounds with an epoxy skeleton, such as heptane, 1,2-epoxy-5-hexene, and 1,7-octadiene monoepoxide; compounds with an epoxide skeleton, such as 3-(acryloyloxymethyl)oxetane, 3-(methacryloyloxymethyl)oxetane, 3-(acryloyloxymethyl)-2-methyloxetane, 3-(methacryloyloxymethyl)-2-methyloxetane, 3-(acryloyloxymethyl)-3-ethyloxetane, and 3-(methacryloyloxymethyl)-3-ethyloxetane. Compounds with a nitrogen-containing aromatic heterocycle, such as 2-(2-pyridylcarbonyloxy)ethyl (meth)acrylate, 2-(3-pyridylcarbonyloxy)ethyl (meth)acrylate, and 2-(4-pyridylcarbonyloxy)ethyl (meth)acrylate; methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, tert-butyl (meth)acrylate, and so on. Cyclohexyl acrylate, isobornyl methacrylate, 2-methoxyethyl methacrylate, methoxytriethylene glycol (meth)acrylate, 2-ethoxyethyl methacrylate, tetrahydrofuran methacrylate, 3-methoxybutyl methacrylate, 2-methyl-2-adamantyl methacrylate, 2-propyl-2-adamantyl methacrylate, 8-methyl-8-tricyclodecyl methacrylate, and 8-ethyl-8-tricyclodecyl methacrylate, etc. (meth)acrylate Ester compounds; (meth)acrylamide compounds such as acrylamide, methacrylamide, N-methacrylamide, N,N-dimethylacrylamide, and N,N-diethylacrylamide; vinyl ether compounds such as methyl vinyl ether, benzyl vinyl ether, vinylnaphthalene, and vinylcarbazole; aromatic vinyl compounds such as styrene, methylstyrene, chlorostyrene, and bromostyrene; and compounds containing maleimide groups such as maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide.

[0047] PXJ (S-mA)

[0048] (In the formula, P represents (meth)acryloyloxy, styryl, vinyloxy (CH2=CH-O-), maleimide or α-methylene-γ-butyrolactone structure.)

[0049] X represents a single bond, -(CH2) a- (a is an integer from 1 to 15), -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -COO-, -OCO-, -CH=CH-COO-CH2-Ak- (Ak represents an alkylene group with 1 to 17 carbon atoms, and a portion of the methylene group in Ak (or all methylene groups when Ak is methylene) is optionally replaced by -O-, -CONH-, -COO-, or -OCO-) or -((CH2) a1 -A1) m1 - (a1 is an integer from 1 to 15, A1 represents an oxygen atom or -COO-, and m1 is an integer from 1 to 2. When m1 is 2, multiple a1 and A1 independently have the above definitions).

[0050] J represents a monovalent organic group having at least one group selected from the group consisting of an alicyclic hydrocarbon group having 4 to 40 carbon atoms and an aromatic hydrocarbon group having 6 to 40 carbon atoms, wherein at least one hydrogen atom of the aforementioned alicyclic hydrocarbon group and aromatic hydrocarbon group is substituted by a substituent selected from the group consisting of a halogen atom, a halogen-containing alkyl group, a halogen-containing alkoxy group, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, an alkenyl group having 3 to 10 carbon atoms, and a heteroatom-containing group formed by the interruption of the carbon-carbon bond of any methylene group of an alkyl group having halogen atom, an alkoxy group having 3 to 10 carbon atoms, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, and an alkenyl group having 3 to 10 carbon atoms. Furthermore, when P is (meth)acryloyloxy, vinyloxy (CH2=CH-O-), or maleimide, X represents a single bond or a group bonded to P via a carbon atom.

[0051] It should be noted that in formula (S-mA), when J is a monovalent organic group having at least one group selected from the group consisting of alicyclic hydrocarbon groups with 4 to 40 carbon atoms and aromatic hydrocarbon groups with 6 to 40 carbon atoms, as long as at least one alicyclic hydrocarbon group or aromatic hydrocarbon group has a substituent as exemplified above, the other alicyclic hydrocarbon groups or aromatic hydrocarbon groups in J may be unsubstituted or may have substituents other than those exemplified above.

[0052] Examples of alkyl groups containing halogen atoms include alkyl groups with 1 to 10 carbon atoms.

[0053] Examples of alkoxy groups containing halogen atoms include alkoxy groups with 1 to 10 carbon atoms.

[0054] Examples of alicyclic hydrocarbon groups, such as J in the above formula (S-mA), include cyclobutane rings, cyclopentane rings, cyclohexane rings, cyclodecane rings, and steroidal skeletons (e.g., cholesteryl, cholesterol, or lanostane). Examples of aromatic hydrocarbon groups include benzene rings and naphthalene rings. When J has at least any one of cyclohexane rings and benzene rings, the group "-X-J" can be represented by structures such as (S1), and more preferably by formulas (S1-1) to (S1-5).

[0055]

[0056] (where X) 1 Indicates a single bond, -(CH2) a - (a is an integer from 1 to 15), -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -COO-, -OCO-, -CH=CH-COO-CH2-Ak- (Ak represents an alkylene group with 1 to 17 carbon atoms, and a portion of the methylene group in Ak (or all methylene groups when Ak is methylene) is optionally replaced by -O-, -CONH-, -COO-, or -OCO-) or -((CH2) a1 -A1) m1 - (a1 is an integer from 1 to 15, A1 represents an oxygen atom or -COO-, and m1 is an integer from 1 to 2. When m1 is 2, multiple a1 and A1 independently have the above definitions).

[0057] G 1 The term indicates a divalent cyclic group selected from phenylene and cyclohexene. Any hydrogen atom on the cyclic group may optionally be replaced by an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorinated alkyl group having 1 to 3 carbon atoms, a fluorinated alkoxy group having 1 to 3 carbon atoms, or a fluorine atom.

[0058] m is an integer from 1 to 4. When m is 2 or greater, there are multiple X... 1 and G 1 Each of them independently possesses the above definition.

[0059] R 1 It refers to a fluorine atom, an alkyl group containing fluorine atoms with 1 to 10 carbon atoms, an alkoxy group containing fluorine atoms with 1 to 10 carbon atoms, an alkyl group with 3 to 10 carbon atoms, an alkoxy group with 3 to 10 carbon atoms, or an alkoxyalkyl group with 3 to 10 carbon atoms.

[0060]

[0061] (where X) 1 and R 1 X in the above formula (S1)1 and R 1 The meaning is the same.

[0062] When the monomer (a-1) having polymerizable unsaturated bonds contains a compound represented by formula (S-mA), the proportion of the compound represented by formula (S-mA) in the monomer (a-1) having polymerizable unsaturated bonds is preferably 5 mol% to 90 mol%, more preferably 10 mol% to 90 mol%, from the viewpoint of appropriately obtaining the effects of the present invention.

[0063] Polymer (A-1) can be obtained, for example, by polymerizing monomers having polymerizable unsaturated bonds in the presence of a polymerization initiator. Examples of polymerization initiators used include azo compounds such as 2,2'-azobis(isobutyronitrile) and 2,2'-azobis(2,4-dimethylpentanonitrile). The proportion of the polymerization initiator used is preferably 0.01 to 30 parts by mass relative to 100 parts by mass of all monomers used in the reaction. The polymerization reaction is preferably carried out in an organic solvent. Examples of organic solvents used in the reaction include alcohols, ethers, ketones, amides, esters, and hydrocarbon compounds, preferably diethylene glycol ethyl methyl ether and propylene glycol monomethyl ether acetate. The reaction temperature is preferably set to 30 to 120°C. The amount (a) of organic solvent used is preferably 0.1 to 60% by mass of the total amount (b) of monomers used in the reaction relative to the total amount (a+b) of the reaction solution.

[0064] Regarding the molecular weight of the polymer (A-1) used in this invention, taking into account the strength of the liquid crystal alignment film obtained therefrom, the workability during film formation, and the coating properties, it is preferably set to 5,000 to 1,000,000, more preferably 10,000 to 150,000, measured by the weight-average molecular weight (Mw) method determined by GPC (Gel Permeation Chromatography).

[0065] (Polyimide precursor (A-2) and polyimide (A-3))

[0066] The polyimide precursor (A-2) is obtained by reacting a diamine component with a tetracarboxylic acid component. Examples of diamines contained in the diamine component include substances described later. It should be noted that a single diamine may be used, or two or more may be used in combination.

[0067] Polyimide (A-3) is an imide derivative of polyimide precursor (A-2).

[0068] It should be noted that when component (A) contains both polyimide precursor (A-2) and polyimide (A-3), the polyimide precursor (A-2) and polyimide (A-3) can be the same component or different components.

[0069] The carboxyl groups in the polyimide precursor (A-2) and polyimide (A-3) can be derived from the ring-opening of tetracarboxylic dianhydride or from a carboxyl-containing diamine. Furthermore, the polyimide precursor (A-2) can also be synthesized using a carboxyl-containing diamine.

[0070] Examples of carboxyl-containing diamines include: 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, 4,4'-diaminobiphenyl-3-carboxylic acid, 4,4'-diaminodiphenylmethane-3-carboxylic acid, 4,4'-diaminodiphenylethane-3-carboxylic acid, 4,4'-diaminobiphenyl-3,3'-dicarboxylic acid, 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid, 3,3'-diaminobiphenyl-4,4'-dicarboxylic acid, 3,3'-diaminobiphenyl-2,4'-dicarboxylic acid, 4,4'-diaminodiphenylmethane-3,3'-dicarboxylic acid, 4,4'-diaminodiphenylethane-3,3'-dicarboxylic acid, and 4,4'-diaminodiphenyl ether-3,3'-dicarboxylic acid.

[0071] As a diamine that can be used to synthesize the polyimide precursor (A-2), a diamine other than the carboxyl-containing diamines mentioned above (hereinafter also referred to as other diamines) can be used. The following diamines can be listed as examples of the other diamines mentioned above.

[0072] Aromatic diamines (d) having the structure shown by the group "-X-J" in the above formula (S-mA) on the side chain, including p-phenylenediamine, 2,3,5,6-tetramethylp-phenylenediamine, 2,5-dimethylp-phenylenediamine, m-phenylenediamine, 2,4-dimethylm-phenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 2,2'-difluoro-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-diaminobiphenyl, 2,2'-bis(tri) 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 4,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'-diaminobiphenyl, 2,3'-diaminobiphenyl, 1,5-diaminonaphthalene, 1,6-diaminonaphthalene, 1,7-diaminonaphthalene, 2,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,7-diaminonaphthalene, bis(4-aminophenoxy)methane, 1,2-bis(4-aminophenyl)ethane, 1,3-bis(3-aminophenyl)propane, 1,4-bis(4-aminophenyl)butane, 1,4-bis(4-aminophenyl)propane 1,4-Diethyl-2-methylphenoxy)butane, 1,4-bis(3-aminophenyl)butane, bis(3,5-diethyl-4-aminophenyl)methane, 1,5-bis(4-aminophenoxy)pentane, 1,5-bis(3-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, 1,6-bis(3-aminophenoxy)hexane, 1,7-bis(4-aminophenoxy)heptane, 1,7-bis(3-aminophenoxy)heptane, 1,8-bis(4-aminophenoxy)octane, 1,8-bis(3-aminophenoxy)octane, 1,9-bis(4-aminophenoxy)nonane, 1,9-bis(3-aminophenoxy)nonane, 1,10-bis(4-aminophenoxy)decane 1,10-bis(3-aminophenoxy)decane, 1,11-bis(4-aminophenoxy)undecane, 1,11-bis(3-aminophenoxy)undecane, 1,12-bis(4-aminophenoxy)dodecane, 1,12-bis(3-aminophenoxy)dodecane, 3-[2-[2-(4-aminophenoxy)ethoxy]ethoxy]aniline, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4-bis(4-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)diphenyl ether, 1,4-bis[4-(4-aminophenoxy)phenoxy]benzene, 1,2-bis(6-amino-2-naphthoxy)ethane, 1,2-Di(6-amino-2-naphthyl)ethane, 6-[2-(4-aminophenoxy)ethoxy]-2-naphthylamine, 4'-[2-(4-aminophenoxy)ethoxy]-[1,1'-biphenyl]-4-amine, 1,4-bis[2-(4-aminophenyl)ethyl]succinate, 1,6-bis[2-(4-aminophenyl)ethyl]hexadiate, 1,4-phenylenebis(4-aminobenzoate), 1,4-phenylenebis(3-aminobenzoate), 1,3-phenylenebis(4-aminobenzoate), 1,3-phenylenebis(3-aminobenzoate), bis(4-aminophenyl)terephthalate, bis(3-aminophenyl)terephthalate, bis(4-aminophenyl)isophthalate, bis(3-aminophenyl)terephthalate, bis(3 ... Diamines with photo-oriented groups, such as 4,4'-diaminoazobenzene or diaminodiphenylacetylene; diamines with photopolymerizable groups at the ends, such as 2-(2,4-diaminophenoxy)ethyl methacrylate and 2,4-diamino-N,N-diallyl aniline; diamines with groups at the ends that function as free radical polymerization initiators, such as 1-(4-(2-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylpropionanone, 2-(4-(2-hydroxy-2-methylpropionyl)phenoxy)ethyl-3,5-diaminobenzoate, benzoin or its alkyl ethers, benzyl ketals, acetophenones, phosphine oxides, benzophenones, or aminobenzophenones. Diamines with amide bonds, such as 4,4'-diaminobenzoyl aniline; diamines with urea bonds, such as 1,3-bis(4-aminophenyl)urea, 1,3-bis(4-aminobenzyl)urea, and 1,3-bis(4-aminophenylethyl)urea; 4,4'-sulfonyl diphenylamine, 3,3'-sulfonyl diphenylamine, bis(4-aminophenyl)silane, bis(3-aminophenyl)silane, dimethyl-bis(4-aminophenyl)silane, dimethyl-bis(3-aminophenyl)silane, 4,4'-dithiodiphenylamine, 3,3'-dithiodiphenylamine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'- bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2'-bis(4-aminophenyl)hexafluoropropane, 2,2'-bis(3-aminophenyl)hexafluoropropane, 2,2'-bis(3-amino-4-methylphenyl)hexafluoropropane, 2,2'-bis(4-aminophenyl)propane, 2,2'-bis(3-aminophenyl)propane, 2,2'-bis(3-amino-4-methylphenyl)propane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene; 2,6-diaminopyridine, 3...4-Diaminopyridine, 2,4-Diaminopyrimidine, 3,6-Diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N-(3-(1H-imidazol-1-yl)propyl-3,5-diaminobenzamide, 4-[4-[(4-aminophenoxy)methyl]-4,5-dihydro-4-methyl-2-oxazolyl]-aniline, 1,4-bis(p-aminobenzyl)piperazine, 4,4'-[4,4'-propane-1,3-diylbis(piperidine-1,4-diyl)]diphenylamine, 4-(4-aminophenoxycarbonyl)-1-(4-aminophenyl) Piperidine, diamines represented by formulas (z-1) to (z-5) below, 2,5-bis(4-aminophenyl)pyrrole, 4,4'-(1-methyl-1H-pyrrole-2,5-diyl)bis[aniline], 1,4-bis-(4-aminophenyl)-piperazine, 2-N-(4-aminophenyl)pyridine-2,5-diamine, 2-N-(5-aminopyridin-2-yl)pyridine-2,5-diamine, 2-(4-aminophenyl)-5-aminobenzimidazole, 2-(4-aminophenyl)-6-aminobenzimidazole and other heterocyclic diamines, or 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl-N-methylamine, N,N'-bis(4-aminophenyl)-1,4-phenylenediamine, N,N'-bis(4-aminophenyl) Diamines with a diphenylamine structure, such as N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine or N,N'-bis(4-aminophenyl)-N,N'-dimethyl-1,4-phenylenediamine, are diamines having at least one nitrogen-containing structure selected from the group consisting of nitrogen-containing heterocycles, secondary amino groups, and tertiary amino groups (wherein, the molecule does not have an amino group bonded to a protecting group that is removed by heating and substituted with a hydrogen atom); 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 4,4'-diamino-3,3'-dihydroxybiphenyl; 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 4-(2-aminophenyl ... 1-(4-aminophenyl)-1,3,3-trimethyl-1H-indane-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indane-6-amine; N1,N4-bis(2-tert-butoxycarbonylamino-4-aminophenyl)hexadiamide, 4-amino-N-(2-tert-butoxycarbonylamino-4-aminophenyl)benzamide, N-[(2,5-diaminophenyl)methyl]-1,1-dimethyl ethyl ester of carbamate, N-[3-(2,5-diaminophenyl)propyl]-1,1-dimethyl ethyl ester of carbamate, N,N-[(2,5-diamino-1,3-phenylene)di-3,1-propanediyl]bis-C,C-bis(1,1-Dimethylethyl) ester, N-tert-butoxycarbonyl-N-(2-(4-aminophenyl)ethyl)-N-(4-aminobenzyl)amine, 4-amino-2-tert-butoxycarbonylamino-1,1'-[(1,1,3,3-tetramethyl-1,3-disiloxanediyl)di-4,1-butanediyl] ester, N-[2-(4-aminophenyl)ethyl]-N-[[[2-(4-aminophenyl)ethyl]amino]carbonyl]-1,1-dimethylethyl ester, N-(4-aminophenyl)-N-[[1-(4-aminophenyl)-4-piperidinyl]methyl]-1,1-dimethylethyl Diamines such as esters having the group "-N(D)-" (D represents a protecting group that is removed and replaced by a hydrogen atom by heating, preferably tert-butoxycarbonyl); diamines such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane having a siloxane bond; diamines such as m-phenylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), and diamines formed by bonding two amino groups to any of the formulas (Y-1) to (Y-167) described in WO2018 / 117239.

[0073]

[0074] Specific examples of the above-mentioned aromatic diamines (d) include diamines represented by the following formulas (d1-1) to (d1-2). More preferred specific examples include diamines with a steroidal skeleton, such as diamines represented by formulas (d1-1) to (d1-2) whose group "-X-J" is any of the above-described structures (S1) or formulas (S1-1) to (S1-5), cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholesteryl ester of 3,5-diaminobenzoate, cholesteryl ester of 3,5-diaminobenzoate, cholesteryl ester of 3,5-diaminobenzoate, and lanostane of 3,6-bis(4-aminobenzoyloxy)cholestane.

[0075]

[0076] (In the formula, X and J, including the preferred embodiment, have the same meaning as X and J in formula (S-mA). In formula (d1-2), the two X and J can be the same or different from each other.)

[0077] When the diamine component comprises an aromatic diamine (d) having a structure represented by the group "-X-J" on the side chain, the proportion of the aromatic diamine (d) in the diamine component is preferably 5 mol% to 90 mol%, more preferably 10 mol% to 90 mol%, from the viewpoint of properly obtaining the effects of the present invention.

[0078] Examples of tetracarboxylic acid components that can be used to synthesize the aforementioned polyimide precursor (A-2) include: acyclic aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, aromatic tetracarboxylic dianhydrides, or derivatives thereof. More preferably, tetracarboxylic dianhydrides or derivatives thereof contain at least one partial structure selected from the group consisting of a benzene ring, a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring. Even more preferably, tetracarboxylic dianhydrides or derivatives thereof contain at least one partial structure selected from the group consisting of a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring.

[0079] As a tetracarboxylic acid component that can be used to synthesize polyimide precursor (A-2), it is preferable to include the following tetracarboxylic dianhydride or its derivatives (hereinafter, they are also collectively referred to as specific tetracarboxylic acid derivatives).

[0080] It should be noted that the following can be listed as derivatives of the above-mentioned tetracarboxylic dianhydride: tetracarboxylic dihalides, tetracarboxylic dialkyl esters, or tetracarboxylic dialkyl ester dihalides. The above-mentioned tetracarboxylic dianhydride or its derivatives can be used alone or in combination of two or more.

[0081] Acyclic aliphatic tetracarboxylic anhydrides such as 1,2,3,4-butanetetracarboxylic anhydride; 1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,3-difluoro-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,3-bis(trifluoromethyl)-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,2,3 4-Cyclopentanetetracarboxylic dianhydride, 1,2,4,5-Cyclohexanetetracarboxylic dianhydride, 3,3',4,4'-Dicyclohexyltetracarboxylic dianhydride, 2,3,5-Tricarboxycyclopentylacetic dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)tetrahydronaphthyl-1,2-dicarboxylic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, bicyclo[2 [2.2.2] Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, bicyclic [2.2.2]octane-2,3,5,6-tetracarboxylic dianhydride, 2,4,6,8-tetracarboxylic bicyclic [3.3.0]octane-2:4,6:8-dianhydride and other alicyclic tetracarboxylic dianhydrides; pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyl sulfone tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3',4,4'-biphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-perfluoroisopropylidene dicarboxylic dianhydride Aromatic tetracarboxylic acid dianhydrides such as phthalic acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylpropane dianhydride, ethylene glycol bis(triphenylene) anhydride, 4,4'-(hexafluoroisopropylidene)diphthalic acid anhydride, 4,4'-carbonyldiphthalic acid anhydride, 4,4'-oxydi(1,4-phenylene)bis(phthalic acid) dianhydride, or 4,4'-methylenedi(1,4-phenylene)bis(phthalic acid) dianhydride; and tetracarboxylic acid dianhydrides as described in Japanese Patent Application Publication No. 2010-97188.

[0082] Preferred examples of the aforementioned specific tetracarboxylic acid derivatives include 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-difluoro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-bis(trifluoromethyl)-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3',4,4'-dicyclohexyltetracarboxylic dianhydride, 2,3,5-tricarboxylated cyclopentylacetic acid dianhydride, and 5-(2,5-dioxanetetracarboxylic acid). 5-(2,5-dioxatetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxylic acid bicyclo[3.3.0]octane-2:4,6:8-dianhydride, pyromellitic acid di Anhydrides, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyl sulfone tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3',4,4'-biphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-biphenyl tetracarboxylic dianhydride, 2,2',3,3'-biphenyl tetracarboxylic dianhydride, or derivatives thereof.

[0083] The proportion of the aforementioned specific tetracarboxylic acid derivative used relative to 1 mole of all tetracarboxylic acid components used is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 50 mol% or more.

[0084] <Preparation of Polyimide Precursors and Polyimide>

[0085] Polyimide (A-3) is an imide derivative of a polyimide precursor, obtained by dehydrating and cyclizing the polyimide precursor. Specific examples of the aforementioned polyimide precursors include polyamic acid and polyamic esters.

[0086] (Synthesis of polyamic acid)

[0087] The synthesis of polyamic acid is carried out by reacting a diamine component containing the above-mentioned diamine with a tetracarboxylic acid component containing the above-mentioned tetracarboxylic dianhydride or its derivative in an organic solvent.

[0088] Specific examples of the aforementioned organic solvents include: cyclohexanone, cyclopentanone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and 1,3-dimethyl-2-imidazolinone. Furthermore, when the polymer has high solvent solubility, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, diethylene glycol monomethyl ether, or diethylene glycol monoethyl ether can be used.

[0089] Polyamates can be obtained, for example, by the following known methods: [I] reacting the polyamic acid obtained by the above method with an esterifying agent, [II] reacting a tetracarboxylic acid diester with a diamine, [III] reacting a tetracarboxylic acid diester dihalide with a diamine, etc.

[0090] Furthermore, polyimide can be obtained by cyclizing (imidizing) the above-mentioned polyimide precursor. It should be noted that the imidization rate mentioned in this specification refers to the proportion of imide groups in the total amount of imide groups and carboxyl groups (or their derivatives) derived from tetracarboxylic dianhydride or its derivatives. The imidization rate does not necessarily have to be 100% and can be adjusted arbitrarily according to the application and purpose.

[0091] <Terminal Modifiers>

[0092] When synthesizing the polyimide precursor and polyimide of the present invention, it can also be synthesized by using an appropriate end-modifying agent together with a tetracarboxylic acid component containing tetracarboxylic dianhydride or its derivative as described above and a diamine component containing the above-mentioned diamine.

[0093] Examples of end-modifying agents include: acetic anhydride, maleic anhydride, nadic anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, 3-(3-trimethoxysilyl)propyl-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, 4-ethynyl phthalic anhydride, etc.; dicarbonate diesters such as ditert-butyl dicarbonate and diallyl dicarbonate; chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride, and nicotinyl chloride; and aniline. Monoamine compounds such as 2-aminophenol, 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, and n-octylamine; monoisocyanate compounds such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate, 2-acryloyloxyethyl isocyanate, and 2-methacryloyloxyethyl isocyanate; and isothiocyanate compounds such as ethyl isothiocyanate and allyl isothiocyanate.

[0094] The proportion of the terminal modifier used relative to 100 moles of the total diamine component used is preferably 0.01 to 20 moles, more preferably 0.01 to 10 moles.

[0095] Regarding the molecular weight of the polyimide precursor and polyimide used in this invention, taking into account the strength, workability during film formation, and coating properties of the resulting liquid crystal alignment film, the weight-average molecular weight (Mw) measured by GPC (Gel Permeation Chromatography) is preferably set to 5,000 to 1,000,000, more preferably 10,000 to 150,000. Furthermore, the molecular weight distribution (Mw / Mn), expressed as the ratio of Mw to the number-average molecular weight (Mn) of polystyrene measured by GPC, is preferably 15 or less, more preferably 10 or less. Regarding the solution viscosity of the polyimide precursor and polyimide, for example, when prepared as a 10% by mass solution, a solution viscosity of 10 to 800 mPa·s is preferred, more preferably 15 to 500 mPa·s. It should be noted that the solution viscosity (mPa·s) is a value determined using an E-type rotational viscometer at 25°C for a 10% by mass polymer solution prepared using the polyimide precursor and a good solvent for the polyimide (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0096] <(B) Component>

[0097] The liquid crystal alignment agent of the present invention contains the above-mentioned component (B). It should be noted that the compound (B) contained in component (B) may be one or more.

[0098] Component (B) acts as an adhesive to bond component (A) and component (C). Component (B) has multiple epoxy groups, and therefore undergoes cross-linking reactions with the carboxyl groups of component (A) as well as with the carboxyl groups of component (C).

[0099] Specific examples of the above-mentioned compound (B) include: compounds (B-1) that do not contain tertiary nitrogen atoms, have two epoxy groups, and have a molecular weight of less than 2000; and compounds (B-2) that contain tertiary nitrogen atoms, have two or more epoxy groups, and have a molecular weight of less than 2000.

[0100] Specific examples of compounds (B-1) that do not contain tertiary nitrogen atoms, have two or more epoxy groups, and have a molecular weight of less than 2000 include: ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, 2,2-dibromonepentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, bisphenol A type epoxy resins such as EPIKOTE 828 (manufactured by MITSUBISHI CHEMICAL), and EPIKOTE 807 (manufactured by MITSUBISHI CHEMICAL). Epoxy resins include bisphenol F type (manufactured by CHEMICAL), hydrogenated bisphenol A type epoxy resin such as YX-8000 (manufactured by MITSUBISHI CHEMICAL), epoxy resins containing biphenyl backbone such as YX6954BH30 (manufactured by MITSUBISHI CHEMICAL), phenolic varnish type epoxy resin such as EPPN-201 (manufactured by Nippon Kayaku Co.), (ortho-, meta-, para-)cresol varnish type epoxy resin such as EOCN-102S (manufactured by Nippon Kayaku Co.), and alicyclic epoxy resins such as Celloxide 2021P (manufactured by Daicel Chemical Industries).

[0101] Specific examples of compounds (B-2) containing the aforementioned tertiary nitrogen atom, having two or more epoxy groups, and with a molecular weight of less than 2000 include: N,N,N',N'-tetraglycidyl-1,4-phenylenediamine, N,N,N',N'-tetraglycidyl-2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2-bis[4-(N,N-diglycidyl-4-aminophenoxy)phenyl]propane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, etc., in which the tertiary nitrogen atom is bonded to an aromatic carbon atom; N,N,N',N'-tetraglycidyl-1,2-diaminocyclohexane, N,N,N',N'-tetraglycidyl-1,3-diaminocyclohexane, N,N,N ',N'-tetraglycidyl-1,4-diaminocyclohexane, bis(N,N-diglycidyl-4-aminocyclohexyl)methane, bis(N,N-diglycidyl-2-methyl-4-aminocyclohexyl)methane, bis(N,N-diglycidyl-3-methyl-4-aminocyclohexyl)methane, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,4-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,3-bis(N,N-diglycidylaminomethyl)benzene, 1,4-bis(N,N-diglycidylaminomethyl)benzene, 1,3,5-tris(N,N-diglycidylaminomethyl)cyclohexane, 1,3,5-tris(N,N-diglycidylaminomethyl)benzene, and the following formula (E N -1)~(E N Compounds shown in -5) are compounds in which tertiary nitrogen atoms are bonded to aliphatic carbon atoms, and triglycidyl isocyanurate such as TEPIC (manufactured by Nissan Chemical Co., Ltd.).

[0102]

[0103] The content of the above-mentioned compound (B) contained in the liquid crystal alignment agent of the present invention is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of component (A), more preferably 0.1 to 20 parts by mass, and even more preferably 5 to 20 parts by mass.

[0104] <(C) Ingredients>

[0105] The liquid crystal alignment agent of the present invention contains the above-mentioned component (C). It should be noted that the compound (C) contained in component (C) may be one or more.

[0106] Because component (C) has a carboxyl group, it undergoes cross-linking with the epoxy group of component (B) as described above. Therefore, a bond is formed between components (A), (B), and (C). Furthermore, component (C) is a low molecular weight component and has specific groups such as alkylene groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups, thus its tendency to be more pronounced towards the liquid crystal layer is expected. In addition, component (C) has polymerizable unsaturated bonds, thus the cross-linking reaction between the polymerizable unsaturated bonds of component (C) and the polymeric liquid crystal layer occurs, resulting in high adhesion to the liquid crystal layer. Moreover, component (C) has a small number of polymerizable unsaturated bonds within its molecule, thus maintaining high liquid crystal alignment in the liquid crystal alignment film and achieving high transmittance in the transmission state.

[0107] As an alkylene group that can be present in compound (C), examples include linear alkylene groups having 1 to 20 carbon atoms. From the viewpoint of properly obtaining the effects of the present invention, it is more preferable for the alkylene group that can be present in compound (C) to be a linear alkylene group having 2 to 20 carbon atoms, and even more preferably a linear alkylene group having 4 to 20 carbon atoms.

[0108] As specific examples of compound (C), the following are examples of compounds with a molecular weight of less than 2000.

[0109] • A carboxyl-containing (meth)acrylate compound (C-1) having at least one cyclic group (hereinafter also referred to as cyclic group (Cy)) selected from the group consisting of alicyclic hydrocarbon groups (cyclobutane ring, cyclopentane ring, cyclohexane ring, cyclodecane ring, steroid skeleton, etc.) with 4 to 40 carbon atoms and aromatic hydrocarbon groups (benzene ring, naphthalene ring, etc.) with 6 to 40 carbon atoms.

[0110] • A vinyl-containing aromatic carboxylic acids (C-2) having the above-mentioned cyclic group (Cy).

[0111] • Maleimides containing a carboxyl group (C-3) having the above-mentioned cyclic group (Cy).

[0112] • A carboxyl-containing (meth)acrylamide compound (C-4) having the above-mentioned cyclic group (Cy).

[0113] (Hereafter, (C-1) to (C-4) will be collectively referred to as compound (mc)).

[0114] • (Meth)acrylate compounds having alkylene groups (C-5) (wherein, the above-mentioned compound (mc) is not included).

[0115] Examples of (meth)acrylate compounds with alkylene groups (C-5) include: 2-carboxyethyl (meth)acrylate, 2-carboxypropyl (meth)acrylate, 5-carboxypentyl (meth)acrylate, 2-(2-acryloyloxy)ethyl succinate, 2-(2-methacryloyloxy)ethyl succinate, etc., which have at least one carboxyl group and a polymerizable unsaturated bond within their molecules and have a molecular weight of less than 2000.

[0116] Preferably, the above-mentioned compound (mc) contains an organic group represented by the following formula (w) within its molecule.

[0117] Furthermore, compounds (mc) containing an organic group of formula (w) in which ring A' is a benzene ring or a naphthalene ring are preferred.

[0118]

[0119] (In the formula, m represents an integer from 0 to 4. Ring A and ring A' each independently represent a benzene ring, a naphthalene ring, or a cyclohexane ring, and the hydrogen atoms on the benzene ring, naphthalene ring, and cyclohexane ring are optionally substituted with monovalent organic groups. L represents a single bond, -O-, -CO-, -CH=CH-COO-, -OCO-, or -COO-. *1 represents a bonded bond, and *2 represents a bonded bond to a carboxyl group or the group "-CH=CH-COOH". When there are two or more L and ring A, the two or more L and ring A can be the same or different independently.)

[0120] Preferred specific examples of compounds (mc) include: vinyl-containing aromatic carboxylic acids such as 4-vinylbenzoic acid (mc-1) to (mc-16); carboxyl-containing maleimides such as 4-maleimide benzoic acid; and carboxyl-containing (meth)acrylamide compounds such as N-(4-carboxyphenyl)methacrylamide and N-(4-carboxyphenyl)acrylamide. In formulas (mc-1) to (mc-16), from the viewpoint of appropriately obtaining the effects of the present invention, n is more preferably an integer from 2 to 20, and even more preferably an integer from 4 to 20.

[0121]

[0122] (n is an integer from 1 to 20.)

[0123] The content of the above-mentioned compound (C) contained in the liquid crystal alignment agent of the present invention is preferably 0.1 to 30 parts by mass relative to the total 100 parts by mass of component (A), more preferably 0.1 to 20 parts by mass, and even more preferably 5 to 20 parts by mass.

[0124] (Liquid crystal alignment agent)

[0125] The liquid crystal alignment agent of the present invention, as described above, contains components (A), (B), and (C) as essential components, and is preferably prepared by dissolving them in an organic solvent. The proportion of component (A) used in the liquid crystal alignment agent of the present invention is not particularly limited; for example, the content of component (A) in the liquid crystal alignment agent is 0.1 to 30% by mass relative to the liquid crystal alignment agent, preferably 1 to 10% by mass.

[0126] The organic solvent contained in the liquid crystal alignment agent is not particularly limited as long as it can dissolve the polymer. Examples include lactone solvents such as γ-valerolactone and γ-butyrolactone; and solvents such as γ-butyrolactam, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-(n-propyl)-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(tert-butyl)-2-pyrrolidone, N-(n-pentyl)-2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, and N- Lactam solvents such as methoxybutyl-2-pyrrolidone and N-cyclohexyl-2-pyrrolidone; amide solvents such as N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-dimethylpropionamide, N,N-diethylpropionamide, N,N-dimethyllacticamide, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, and tetramethylurea; cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, 2,6-dimethyl-4-heptanone (diisobutyl ketone), and lactic acid. Methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, ethylene glycol monobutyl 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, propylene glycol monobutyl ether, propylene glycol diacetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, isoamyl propionate, isoamyl isobutyrate, diisopropyl ether, diisoamyl ether; carbonate solvents such as ethylene carbonate and propylene carbonate; 1-hexanol, cyclohexanol, 1,2-ethylene glycol, 2,6-dimethyl-4-heptanol (diisobutylmethanol), etc. They can be used alone or in combination of two or more.

[0127] When the liquid crystal alignment agent of the present invention is applied to plastic substrates or the like, the organic solvent used in the liquid crystal alignment agent can be composed of a solvent with a boiling point of 190°C or less at 1 atmosphere. As a preferred solvent composition in cases where the solvent has a boiling point of 190°C or less at 1 atmosphere, solvent compositions comprising the following combinations can be listed: cyclohexanone and ethylene glycol monobutyl ether; cyclohexanone and propylene glycol monobutyl ether; cyclohexanone and propylene glycol monomethyl ether; cyclopentanone and propylene glycol monobutyl ether; cyclopentanone and propylene glycol monomethyl ether; cyclohexanone and diethylene glycol monoethyl ether; cyclopentanone and diethylene glycol monoethyl ether; cyclohexanone and diisobutyl ketone; cyclopentanone and diisobutyl ketone; methyl isobutyl ketone and propylene glycol monobutyl ether; methyl ethyl ketone and propylene glycol monobutyl ether; cyclohexanone and 4-hydroxy-4-methyl-2-pentanone; cyclopentanone and 4-hydroxy-4-methyl-2-pentanone; cyclohexanone and diethylene glycol diethyl ether; cyclopentanone and diethylene glycol diethyl ether; tetramethylurea and propylene glycol diacetate; N,N-dimethylpropanediol Amides and propylene glycol monobutyl ether; tetramethylurea and propylene glycol monobutyl ether; tetramethylurea, cyclohexanone and propylene glycol monomethyl ether; N,N-dimethylpropionamide and propylene glycol monomethyl ether; N,N-dimethylpropionamide and ethylene glycol monobutyl ether acetate; N,N-dimethylpropionamide and ethylene glycol monobutyl ether; N,N-diethylpropionamide and propylene glycol monomethyl ether; tetramethylurea and propylene glycol monomethyl ether; N,N-dimethylpropionamide, cyclohexanone and diethylene glycol diethyl ether; N,N-diethylformamide and propylene glycol monomethyl ether; N,N-diethylformamide and 4-hydroxy-4-methyl-2-pentanone; cyclohexanone and n-butyl acetate; cyclopentanone and n-butyl acetate; 4-hydroxy-4-methyl-2-pentanone and ethylene glycol monobutyl ether; cyclohexanone and propylene glycol diacetate; and cyclopentanone and propylene glycol diacetate. The type and content of such organic solvents should be appropriately selected based on the coating equipment, coating conditions, and coating environment of the liquid crystal alignment agent.

[0128] The liquid crystal alignment agent of the present invention contains, as described above, components (A), (B), and (C) as essential components, and may also contain other components as needed.

[0129] Other components mentioned above include, for example, polymers other than those constituting component (A) (hereinafter also referred to as other polymers).

[0130] In addition, other components include: crosslinking compounds (D); functional silane compounds; metal chelating compounds; curing accelerators; surfactants; antioxidants; sensitizers; preservatives; compounds used to adjust the dielectric constant and resistance of liquid crystal alignment films; photoradical generators; photoacid generators; photoalkalizers; ultraviolet absorbers; and light stabilizers, etc.

[0131] As a crosslinking compound (D), examples include: at least one crosslinking compound selected from the group consisting of a crosslinking compound (d-1) having at least one substituent selected from isocyanate group, oxetyl group, cyclic carbonate group, terminal isocyanate group, hydroxyl group and alkoxy group; and a crosslinking compound (d-2) having a polymerizable unsaturated group.

[0132] Other polymers are not specifically limited, but may include: polysiloxanes, polyesters, polyamides, polyureas, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene derivatives, poly(styrene-maleic anhydride) copolymers, poly(isobutylene-maleic anhydride) copolymers, poly(vinyl ether-maleic anhydride) copolymers, and poly(styrene-phenylmaleimide) derivatives. Specific examples of poly(styrene-maleic anhydride) copolymers include: SMA1000, SMA2000, SMA3000 (manufactured by Cray Valley), and GSM301 (manufactured by Gifu Shellac Manufacturing). Specific examples of poly(isobutylene-maleic anhydride) copolymers include ISOBAM-600 (manufactured by Kuraray). Specific examples of poly(vinyl ether-maleic anhydride) copolymers include Gantrez AN-139 (methyl vinyl ether maleic anhydride resin, manufactured by Ashland). It should be noted that two or more other polymers may also be used in combination.

[0133] When using other polymers, their usage ratio is preferably 50% by mass or less relative to the total polymers contained in the liquid crystal alignment agent, more preferably 0.1 to 40% by mass, and even more preferably 0.1 to 30% by mass.

[0134] Preferred examples of crosslinking compounds (d-1) and (d-2) include compounds having two or more oxocyclic butyl groups as described in paragraphs 0170 to 0175 of WO2011 / 132751: CORONATE APstable M, CORONATE 2503, 2515, 2507, 2513, 2555, MILLIONATE MS-50 (all manufactured by TOSOH), and TAKENATE. Compounds with terminal isocyanate groups, such as B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, and B-882N (all manufactured by Mitsui Chemicals); N,N,N',N'-tetratetra(2-hydroxyethyl)hexamethylenediamine, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethoxymethylphenyl)propane, and 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)-1,1,1,3,3, Compounds containing hydroxyl and alkoxy groups, such as 3-hexafluoropropane; cross-linked compounds containing polymerizable unsaturated groups, such as glyceryl mono(meth)acrylate, glyceryl di(meth)acrylate (a mixture of 1,2- and 1,3-type compounds), glyceryl tri(meth)acrylate, glyceryl 1,3-diglyceryl alcohol di(meth)acrylate, pentaerythritol tri(meth)acrylate, diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, pentaethylene glycol mono(meth)acrylate, and hexaethylene glycol mono(meth)acrylate.

[0135] The content of the crosslinking compound (D) is preferably 0.01 to 30 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent, more preferably 0.1 to 20 parts by mass, and even more preferably 1 to 20 parts by mass.

[0136] Examples of compounds used to adjust dielectric constant and resistance include monoamines such as 3-aminomethylpyridine, which have nitrogen-containing aromatic heterocycles. When using a monoamine with a nitrogen-containing aromatic heterocycle, the amount is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent, more preferably 0.1 to 20 parts by mass.

[0137] Preferred specific examples of functional silane compounds include: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureopropyltrimethoxysilane, 3-ureopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane. Silane compounds include oxy-based silanes, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-epoxypropoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-acryloyloxypropyltrimethoxysilane, tris(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatopropyltriethoxysilane. When using functional silane compounds, the amount is preferably 0.1 to 30 parts by weight, more preferably 0.1 to 20 parts by weight, relative to 100 parts by weight of the polymer component contained in the liquid crystal alignment agent.

[0138] Specific examples of photoradical generators, photoacid generators, and photoalkali generators can be found in the compounds described on pages 54-56 of WO2014 / 171493. Among these, photoradical generators are preferred from the perspective of the adhesion between the liquid crystal layer and the liquid crystal alignment film of the liquid crystal element.

[0139] Examples of UV absorbers include: inorganic UV absorbers such as titanium dioxide, cerium oxide, zinc oxide, and iron oxide; and organic UV absorbers such as benzotriazole, triazine, and benzophenone. Among these, triazine UV absorbers are preferred.

[0140] Examples of such light stabilizers include hindered amine light stabilizers (HALS). Hindered amine light stabilizers having reactive functional groups are preferred.

[0141] The concentration of solid components in the liquid crystal alignment agent (the proportion of the total mass of components other than the organic solvent in the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) is appropriately selected considering factors such as viscosity and volatility, and is preferably in the range of 1 to 10% by mass. The preferred range of solid component concentration varies depending on the method used to coat the liquid crystal alignment agent onto the substrate. For example, in the case of spin coating, the solid component concentration is particularly preferably in the range of 1.5 to 4.5% by mass. In the case of printing, it is particularly preferably set to a solid component concentration in the range of 3 to 9% by mass, thereby setting the solution viscosity in the range of 12 to 50 mPa·s. In the case of inkjet printing, it is particularly preferably set to a solid component concentration in the range of 1 to 5% by mass, thereby setting the solution viscosity in the range of 3 to 15 mPa·s.

[0142] (Liquid crystal alignment film / liquid crystal element)

[0143] The liquid crystal alignment film of the present invention is obtained from the above-described liquid crystal alignment agent. The liquid crystal alignment film of the present invention can also be used for horizontally aligned or vertically aligned liquid crystal alignment films. The liquid crystal alignment film of the present invention is suitable for liquid crystal alignment films of polymer-dispersed liquid crystal elements described later. The liquid crystal element of the present invention includes the above-described liquid crystal alignment film.

[0144] <Polymer Dispersed Liquid Crystal Elements>

[0145] Figure 1 This is a schematic cross-sectional view illustrating an example of a liquid crystal element of the present invention. The liquid crystal element (100) includes: a pair of substrates, which are composed of a first substrate (11) and a second substrate (17); and a dimming layer (14) disposed between the first substrate (11) and the second substrate (17).

[0146] The dimming layer (14) is a layer that has the following function: to change the transparency according to the state of the electric field applied by the transparent electrodes (12) and (16).

[0147] The dimming layer (14) is formed of a polymer-dispersed liquid crystal, which is a polymer / liquid crystal composite containing a polymer phase and a liquid crystal phase as essential components. There is no particular limitation on the polymer-dispersed liquid crystal, and examples include: liquid crystals (PDLC) formed by dispersing liquid crystal molecules in droplets in a transparent polymer material; polymer network liquid crystals (PNLC) in which a network of polymer resin is formed in a continuous layer of liquid crystal molecules; and polymer-stabilized cholesteric liquid crystals (PSCT) using cholesteric liquid crystal molecules. Hereinafter, an example of a dimming layer (14) formed of the above-mentioned PDLC will be described.

[0148] At once Figure 1In the case of the liquid crystal element shown in the example, in addition to changing whether an electric field is applied to the dimming layer (14), the voltage applied is also changed, thereby switching the transmission state of transmitted light and the non-transmittent state that causes light to scatter.

[0149] More preferred forms of the above-mentioned liquid crystal element are: a conventional type polymer dispersion liquid crystal element that is in a cloudy (light scattering) state when no voltage is applied, and in a transmissive state when a voltage is applied; or a reverse type polymer dispersion liquid crystal element that is in a transmissive state when no voltage is applied, and in a scattering state when a voltage is applied.

[0150] The thickness of the dimming layer (14) is preferably 1 to 30 μm, more preferably 1 to 20 μm, and even more preferably 1 to 15 μm, from the viewpoint of controlling the arrangement of the liquid crystal material and appropriately embodying the dimming function.

[0151] The first substrate (11) and the second substrate (17) are not particularly limited as long as they function as supports for the transparent electrode, and a transparent film material is preferred. There are no particular limitations on the transparent film material used; a flexible transparent film material can be used. For example, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), acrylic resins such as polymethyl methacrylate (PMMA), polyolefin resins such as polypropylene (PP), cellulose resins such as cellulose triacetate (TAC), cyclic olefin polymers (COP), and polycarbonate (PC) resins are preferred. Among these, PET is preferred from the viewpoints of strength, heat resistance, and transparency.

[0152] Furthermore, the thickness of the first substrate (11) and the second substrate (17) is not particularly limited, but from the viewpoint of having sufficient strength to function properly as a substrate, it is preferably 20 to 300 μm, and more preferably 50 to 150 μm.

[0153] As transparent electrodes (12) and (16), there are no particular limitations as long as a reasonably uniform electric field can be applied to the dimming layer (14), and transparent and perceptible transparent conductive materials are preferred. As materials constituting the above-mentioned transparent electrodes, in addition to metal oxides such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), AZO (Aluminum-doped Zinc Oxide), GZO (Gallium-doped Zinc Oxide), ATO (Antimony Tin Oxide), and ZnO (Zinc Oxide), materials containing conductive polymer films, silver nanowires, carbon nanotubes, silver alloys, etc., can also be used.

[0154] Liquid crystal alignment films (13) and (15) are formed on the respective electrode arrangement surfaces of the first substrate (11) and the second substrate (17). The liquid crystal alignment films (13) and (15) are organic thin films that restrict the orientation of liquid crystal molecules in the dimming layer (14). In this embodiment, they are liquid crystal alignment films formed by a liquid crystal alignment agent containing the above-mentioned components (A), (B) and (C). It should be noted that the liquid crystal alignment films (13) and (15) can be provided on at least one of the pair of substrates. From the viewpoint of alignment stability, it is preferable to provide them on both substrates.

[0155] The dimming layer (14) is formed by polymerizing a dimming layer forming material containing a liquid crystal composition and a polymeric compound component after it is disposed in a space surrounded by a pair of substrates and a sealant (not shown). The sealant is configured to surround the outer edge of the electrode placement surface between the pair of substrates.

[0156] <Manufacturing Method of Liquid Crystal Components>

[0157] When the liquid crystal element of the present invention is a polymer dispersion type liquid crystal element, it can be manufactured, for example, by a method including the following steps (1) to (4).

[0158] Step (1): The process of applying the liquid crystal alignment agent of the present invention to one or both of a pair of substrates with electrodes.

[0159] Process (2): A process of firing the coating formed on the substrate by process (1).

[0160] Process (3): The process of preparing the dimming layer forming material.

[0161] Step (4): The process of polymerizing the configured dimming layer forming material to form a dimming layer containing a polymer phase and a liquid crystal phase.

[0162] Furthermore, when the polymer-dispersed liquid crystal element of the present invention is a guest-host type dimming element, it can be manufactured by including the dye described later in the liquid crystal composition. Furthermore, when the liquid crystal element of the present invention is a liquid crystal element other than a polymer-dispersed liquid crystal element, it can be obtained by changing the dimming layer forming material in step (3) to a liquid crystal composition without added polymeric compound components, or to a liquid crystal composition with added polymeric compound components of 5% by mass or less, using the same method as for polymer-dispersed liquid crystal elements. In this case, step (4) can be omitted, or it can be performed as needed. Moreover, the liquid crystal alignment film only needs to be formed on at least one of a pair of substrates; both sides or one side are acceptable.

[0163] (1) A process of coating a liquid crystal alignment agent onto one or both of a pair of substrates with electrodes (process (1))

[0164] For example, the liquid crystal alignment agent of the present invention can be coated onto the electrode arrangement surface of at least one of the electrode substrates using a suitable coating method such as roller coating, spin coating, printing, or inkjet coating. Here, the film substrate or glass substrate described above can be cited as examples of substrates.

[0165] (2) The process of firing the coating (process (2))

[0166] After coating the liquid crystal alignment agent, preheating (pre-baking) is preferably performed first to prevent liquid dripping of the coated liquid crystal alignment agent. The pre-baking temperature is preferably 30–150°C, more preferably 40–130°C, and particularly preferably 50–120°C. The pre-baking time is preferably 0.25–10 minutes, more preferably 0.5–5 minutes, and even more preferably 1–5 minutes. Furthermore, a heating (post-baking) process can be further performed to remove the solvent. The post-baking temperature is preferably 80–190°C, more preferably 120–180°C. The post-baking time is preferably 5–30 minutes, more preferably 5–20 minutes. The film thickness thus formed is preferably 1–1000 nm, more preferably 5–1000 nm, and even more preferably 10–1000 nm.

[0167] The coating formed in step (2) above can be kept in this state and used as a liquid crystal alignment film, or the coating can be subjected to an alignment capability imparting treatment. Examples of alignment capability imparting treatments include: friction treatment by rubbing the coating in a certain direction with a roll of cloth made of fibers such as nylon, rayon, or cotton; and light alignment treatment by irradiating the coating with polarized or unpolarized radiation.

[0168] In the aforementioned photoalignment process, the radiation used to irradiate the coating can be, for example, ultraviolet light or visible light containing wavelengths of 150–800 nm. When the radiation is polarized, it can be linearly polarized or partially polarized. Furthermore, when the radiation used is linearly or partially polarized, irradiation can be performed from a direction perpendicular to the substrate surface, from an oblique direction, or a combination thereof. When irradiating unpolarized radiation, the irradiation direction is set to an oblique direction.

[0169] (3) Process of preparing the dimming layer forming material (process (3))

[0170] As described above, a pair of substrates with electrodes on one or both sides having liquid crystal alignment films are prepared, and a dimming layer forming material is disposed between the two opposing substrates. Specifically, three methods can be listed below. The first method is a method of arranging two substrates opposite each other with a gap (cell gap) between them, with their respective liquid crystal alignment films facing each other, which is called vacuum injection. In PDLC type liquid crystal elements and PNLC type liquid crystal elements, it is preferable to set the cell gap to 1 to 100 μm, more preferably 2 to 50 μm, and even more preferably 5 to 20 μm. Next, the peripheries of the two substrates are bonded together using a sealant, and a dimming layer forming material containing a liquid crystal composition, a polymerizable compound component, and a polymerization initiator as needed is injected into the cell gap defined by the substrate surface and the sealant. After contacting the film surface, the injection hole is sealed.

[0171] Furthermore, a second method is known as the ODF (One Drop Fill) method. For example, a UV-curable sealant is applied to a predetermined area on one of two substrates on which a liquid crystal alignment film is formed. Then, the aforementioned dimming layer forming material is dropped onto predetermined locations on the surface of the liquid crystal alignment film. Next, the other substrate is bonded with the liquid crystal alignment film facing each other, and the liquid crystal composition is spread across the entire surface of the substrate, contacting the film surface. Then, the entire surface of the substrate is irradiated with UV light to cure the sealant.

[0172] Furthermore, the third method is known as the roll-to-roll method. Specifically, this includes coating the aforementioned dimming layer forming material onto the surface of a first electrode-bearing substrate on the side with the transparent conductive film, and then bonding the dimming layer forming material to the surface of a second glass substrate with the transparent conductive film, thereby achieving a uniform thickness. As a method for coating the dimming layer forming material used in this invention, the following commonly known methods can be employed: applicator method, bar coating, roll coating, direct gravure coating, reverse gravure coating, inkjet coating, die coating, CaP coating, etc. Regardless of the method used, it is ideal to further heat the liquid crystal composition to a temperature at which it becomes an isotropic phase, and then slowly cool it to room temperature, thereby removing the flow orientation during liquid crystal filling.

[0173] (Light-adjusting layer forming material)

[0174] The dimming layer forming material of the present invention comprises a liquid crystal composition, a polymerizable compound component, and a polymerization initiator as needed. Furthermore, the dimming layer forming material may further comprise, as needed, an orientation additive, anisotropic dye, ultraviolet absorber / light stabilizer, and chain transfer agent. The proportion of the liquid crystal composition contained in the dimming layer forming material relative to 100 parts by weight of the dimming layer forming material is preferably 40 parts by weight or more, more preferably 50 parts by weight or more, and even more preferably 60 parts by weight or more. It is also preferably 90 parts by weight or less, more preferably 80 parts by weight or less. The content of the polymerizable compound component relative to 100 parts by weight of the dimming layer forming material is preferably 10 parts by weight or more, more preferably 20 parts by weight or more. It is also preferably 60 parts by weight or less, more preferably 50 parts by weight or less, and even more preferably 40 parts by weight or less.

[0175] (Liquid crystal composition)

[0176] Examples of liquid crystal compounds constituting liquid crystal compositions include nematic liquid crystal compounds and smectic liquid crystal compounds. These liquid crystal compounds can be used alone or in combination of two or more. Among the liquid crystal compounds, nematic liquid crystal compounds are preferred, and examples include: Schiff base-based liquid crystal compounds, azo-based liquid crystal compounds, biphenyl-based liquid crystal compounds, phenylcyclohexane-based liquid crystal compounds, ester-based liquid crystal compounds, terphenyl-based liquid crystal compounds, biphenylcyclohexane-based liquid crystal compounds, pyrimidine-based liquid crystal compounds, dioxane-based liquid crystal compounds, bicyclooctane-based liquid crystal compounds, and cubane-based liquid crystal compounds. Furthermore, substances such as cholesterol chloride, cholesterol nonanoate, and cholesterol carbonate can be added to these liquid crystal compounds for example, as well as chiral agents sold under trade names such as "C-15" and "CB-15" (manufactured by MERCK); and strongly dielectric liquid crystal compounds such as p-decoxybenzyl p-amino-2-methylbutylcinnamate.

[0177] As the above-mentioned liquid crystal composition, various substances disclosed in Japanese Patent Application Publication No. 2007-009120 and Japanese Patent Application Publication No. 2011-246411 can be used.

[0178] When used as a conventional type polymer-dispersed liquid crystal element, the liquid crystal composition described above uses a positive liquid crystal composition exhibiting positive dielectric anisotropy (hereinafter also referred to as positive liquid crystal). When used as a reverse type polymer-dispersed liquid crystal element, the liquid crystal composition described above uses a negative liquid crystal composition exhibiting negative dielectric anisotropy (hereinafter also referred to as negative liquid crystal).

[0179] Examples of positive liquid crystal displays include: ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, and MLC-7081 manufactured by MERCK.

[0180] Examples of negative liquid crystals include Sb-323010 manufactured by Shanpen Corporation, and MLC-6608, MLC-6609, or MLC-6610 manufactured by Merck Corporation.

[0181] (Polymerized compound components)

[0182] In PDLC and PNLC liquid crystal elements, the dimming layer forming material preferably contains a polymerizable compound component. As the polymerizable compound component, free radical polymerizable compounds (monomers) and their oligomers are preferred. Alternatively, polymers obtained by polymerizing these monomers can also be used. Specifically, examples include: phosphate compounds containing (meth)acryloyl groups, monofunctional (meth)acrylate compounds, difunctional (meth)acrylate compounds, and trifunctional or higher (meth)acrylate compounds.

[0183] Examples of phosphate ester compounds containing (meth)acrylyl groups include: 2-(meth)acryloxyethyl acid phosphates (e.g., "Light Ester P-1M" and "Light Acrylate P-1A" manufactured by Kyoeisha Chemical Co., Ltd.), bis(2-(meth)acryloxyethyl) acid phosphates (e.g., "Light Ester P-2M" and "Light Acrylate P-2A" manufactured by Kyoeisha Chemical Co., Ltd., and "KAYAMERPM-21" manufactured by Nippon Kayaku Co., Ltd.), and triacryloxyethyl phosphates (e.g., "Viscoat#3PA" manufactured by Osaka Organic Chemical Industry Co., Ltd.), which are ethylene unsaturated compounds containing phosphate groups and have three ethylene unsaturated groups.

[0184] Preferred specific examples of monofunctional (meth)acrylate compounds include: isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, or compounds with an alicyclic hydrocarbon group having a monovalent organic group having a (meth)acryloyloxy group (P) and a carbon atom number of 4 to 40, such as compounds with the above formula (S-mA); 2-hydroxypropyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and partially ethoxylated 2-hydroxypropyl (meth)acrylate. Monofunctional (meth)acrylate compounds having an alcoholic hydroxyl group, such as esters; monofunctional (meth)acrylate compounds having an epoxy group, such as glycidyl methacrylate, α-ethyl (meth)acrylate, α-n-propyl (meth)acrylate, α-n-butyl (meth)acrylate, 3,4-epoxybutyl methacrylate, 4,5-epoxypentyl methacrylate, 3,4-epoxybutyl methacrylate, 6,7-epoxypentyl methacrylate, α-ethyl (meth)acrylate, 6,7-epoxypentyl methacrylate, β-methylglycidyl methacrylate, and 3,4-epoxycyclohexyl methacrylate, or compounds exemplified in the monomers used to obtain the above polymer (A-1).

[0185] Preferred examples of difunctional (meth)acrylate compounds and trifunctional or higher (meth)acrylate compounds include: diethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,3-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, tetraethylene glycol dimethacrylate, 4,4'-biphenyl dimethacrylate, dicyclopentyl dimethacrylate, glyceryl dimethacrylate, 1,9-nonanediol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, and hydroxypentanoic acid-modified neopentyl glycol dimethacrylate (e.g., "KAYARAD HX-220" and "KAYARAD" manufactured by Nippon Kayaku Co., Ltd.). HX-620, etc.), 2,2,3,3,4,4-hexafluoropentanediol-1,5-di(meth)acrylate, or difunctional (meth)acrylate compounds having a carbamate bond (e.g., as difunctional (meth)acrylate compounds having a carbamate bond and an alicyclic structure, such as "EBECRYL 230", "EBECRYL 270", and "EBECRYL 9270" manufactured by Daicel Allnex); trimethylolpropane tri(meth)acrylate (e.g., "NK Ester TMPT" manufactured by Shin-Nakamura Kogyo Co.), pentaerythritol tri(meth)acrylate (e.g., "NK Ester A-TMMT" manufactured by Shin-Nakamura Kogyo Co.), pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetraacrylate (e.g., "NK Ester" manufactured by Shin-Nakamura Kogyo Co.), etc.); pentaerythritol tetra(meth)acrylate; ethoxylated pentaerythritol tetraacrylate (e.g., "NK Ester" manufactured by Shin-Nakamura Kogyo Co.), etc. Trifunctional or higher (meth)acrylate compounds, such as "ATM-35E", di(trimethylolpropane)tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate (e.g., "NK Ester A-DPH" manufactured by Shin-Nakamura Kogyo Co., Ltd.), or dipentaerythritol monohydroxypenta(meth)acrylate, or their oligomers, may also be used. In addition to the compounds described above, monofunctional polymerizable compounds, difunctional polymerizable compounds, and polyfunctional polymerizable compounds described on pages 58-60 of WO2015 / 012368, or compounds described in paragraphs 0195-0205 of WO2018 / 159302 may also be used.

[0186] Ionic polymerizable compounds can also be used. Specifically, examples include melamine derivatives, benzoguanamine derivatives, 1,3,5-tris(methoxymethoxy)benzene, 1,2,4-tris(isopropoxymethoxy)benzene, 1,4-bis(sec-butoxymethoxy)benzene, 2,6-dihydroxymethyl-p-tert-butylphenol, and compounds containing epoxy or isocyanate groups, as described on pages 15-16 of WO2014 / 171493.

[0187] When using ionic polymerizable compounds, ionic initiators that generate acids or bases under ultraviolet light can be introduced to promote the polymerization reaction. Specifically, ionic initiators described on pages 16-17 of WO2014 / 171493 can be cited as examples.

[0188] (Polymerization initiator)

[0189] Regarding the material forming the dimming layer, for the purpose of promoting the polymerization reaction of polymerizable compounds, especially promoting the free radical polymerization of polymerizable compounds, it is preferable to introduce a free radical initiator (also known as a photopolymerization initiator) that generates free radicals through ultraviolet light. Specifically, examples include: benzoin and its alkyl ethers, benzyl ketals, acetophenones, acylphosphine oxides, benzophenones, aminobenzophenones, and free radical initiators described on pages 13-14 of WO2014 / 171493. As for the aforementioned acetophenones, for example, hydroxyacetophenone, aminoacetophenone, dialkoxyacetophenone, haloacetophenone, etc., can be used. Commercially available photopolymerization initiators include, for example, BASF's IRGACURE 907 (2-[4-(methylthio)benzoyl]-2-(4-morpholinyl)propane), IRGACURE 651 (2,2-dimethoxy-2-phenylacetophenone), IRGACURE 369 (1-(4-morpholinylphenyl)-2-(dimethylamino)-2-benzyl-1-butanone), IRGACURE 184, or IGMresins' Omnirad 184 (1-hydroxycyclohexylphenyl ketone). The preferred proportion of the polymerization initiator relative to 100 parts by weight of the light-adjusting layer forming material is 0.01 to 5 parts by weight.

[0190] The aforementioned photopolymerization initiators can be used alone or in combination of two or more. Furthermore, free radical initiators can also be used alone or in combination of two or more, depending on their properties.

[0191] (Orientation additives)

[0192] As an orientation additive added to the dimming layer forming material, examples include the compound described in paragraph 0049 of Japanese Patent Application Publication No. 2019-065230.

[0193] From the perspective of the optical properties of the component, the amount of orientation additive used in the dimming layer forming material is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the dimming layer forming material, more preferably 0.5 to 30 parts by mass, and particularly preferably 1 to 20 parts by mass. Two or more orientation additives can be used in combination.

[0194] (Anisotropic dyes)

[0195] The aforementioned dimming layer forming material may also include anisotropic dyes (also known as dichroic dyes or dichroic pigments). The term "isotropic dye" refers to a substance that can anisotropically absorb light in at least a portion or the entire wavelength range of the visible light region, such as 400–700 nm.

[0196] There are no particular restrictions on the type of anisotropic dye; for example, black dyes or colored dyes can be used. Various known substances disclosed in Japanese Patent Application Publication No. 2007-009120 and Japanese Patent Application Publication No. 2011-246411 can be used as such anisotropic dyes. The mixing ratio of the anisotropic dye is, for example, 0.01 to 5 parts by mass relative to 100 parts by mass of the light-adjusting layer forming material; the above ratio can be changed as needed.

[0197] (UV absorber / light stabilizer)

[0198] The aforementioned dimming layer forming material may further include an ultraviolet absorber / light stabilizer. Specific examples of ultraviolet absorbers / light stabilizers include the example compounds described above. The content of the ultraviolet absorber relative to 100 parts by weight of the liquid crystal composition is preferably 0.1 to 3 parts by weight, more preferably 0.1 to 2 parts by weight, and even more preferably 0.3 to 1.5 parts by weight. The content of the light stabilizer relative to 100 parts by weight of the liquid crystal composition is preferably 1 to 10 parts by weight, more preferably 2 to 8 parts by weight, and even more preferably 3 to 6 parts by weight.

[0199] (Chain transfer agent)

[0200] The dimming layer forming material described above may further include a chain transfer agent. Preferred specific examples of chain transfer agents are butanediol dithiopropionate, pentaerythritol tetra(3-mercaptobutyrate), triethylene glycol dithiol, etc.

[0201] To prevent excessive cross-linking of the polymer phase, the liquid crystal material can easily respond to the electric field and be driven by low voltage.

[0202] The content of the chain transfer agent is preferably 0.05 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, relative to 100 parts by mass of the polymerizable compound component.

[0203] (4) The process of polymerizing the dimming layer forming material to form a dimming layer containing a polymer phase and a liquid crystal phase (process (4))

[0204] Methods for polymerizing the dimming layer forming material of the present invention include irradiation with active energy rays and thermal polymerization. Among these, polymerization of the dimming layer forming material is preferably carried out by irradiation with ultraviolet light. Furthermore, methods of ultraviolet irradiation include irradiating one of a pair of substrates with electrodes with ultraviolet light. Examples of light sources for the ultraviolet irradiation apparatus include metal halide lamps or high-pressure mercury lamps. In this case, the wavelength of the ultraviolet light is preferably 250–400 nm, and more preferably 310–370 nm.

[0205] The intensity of ultraviolet light irradiation can be appropriately determined through experiments, or its endpoint can be determined by the concentration of unreacted polymeric compounds in the liquid crystal composition.

[0206] The optimal amount of ultraviolet light irradiation is 0.05 J / cm. 2 The above is particularly preferred to be 1.0 J / cm. 2 The above. The preferred ultraviolet radiation intensity is 1 mW / cm². 2 In order to complete the polymerization of the polymerizable compound, a concentration of 20 mW / cm² can be used. 2 The irradiation time of ultraviolet light is 1 to 3600 seconds, more preferably 60 to 3600 seconds, and even more preferably 60 to 1800 seconds. Furthermore, the irradiation period can be in a state where a voltage is applied between the electrodes or in a state where no voltage is applied between the electrodes.

[0207] Furthermore, both ultraviolet treatment and heat treatment can be performed simultaneously, or heat treatment can be performed after ultraviolet treatment. The preferred temperature for heat treatment is 20–120°C, more preferably 30–100°C.

[0208] The liquid crystal element of this invention is preferably used in liquid crystal elements for transportation equipment and machinery such as automobiles, railways, and aircraft. Specifically, it is preferably used in dimming windows for controlling light transmission and isolation, optical shutter elements for indoor mirrors, etc. Furthermore, the liquid crystal element of this invention can also be used in light guide plates of display devices such as liquid crystal displays and organic light-emitting diode displays; and in the back panels of transparent displays using these displays. Specifically, when used in the back panel of a transparent display, the transparent display and the liquid crystal element of this invention can be combined to suppress light from entering from the back side when displaying an image on the transparent display.

[0209] Example

[0210] The present invention will be further described in detail below with examples, but the invention is not limited to these examples. The abbreviations of the compounds used and the methods for measuring their properties are described below.

[0211] (liquid crystal)

[0212] L1: Sb-323010 (negative type liquid crystal, manufactured by Sinotron Co., Ltd.).

[0213] (polymeric compounds)

[0214] R1: Isobornyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., IBXA).

[0215] R2: The compound component shown in the following formula [R2] (manufactured by Nippon Kayaku Co., Ltd., KAYARAD HX-220, where m and n are integers that satisfy the sum of m and n being 2, or a mixture containing multiple compounds).

[0216] R3: The compound component shown in the following formula [R3] (manufactured by Nippon Kayaku Co., Ltd., KAYARAD HX-620, where m' and n' are integers that sum to 4, or can be a mixture containing multiple compounds).

[0217] R4: The compound component represented by the following formula [R4] (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., ethoxylated pentaerythritol tetraacrylate, NK Ester ATM-35E, where a, b, c, and d are integers satisfying that the sum of a, b, c, and d is 35, or may be a mixture containing multiple compounds).

[0218] R5: Pentaerythritol tetra(3-mercaptobutyrate) (manufactured by Showa Denko Co., Ltd., KarenzMT PE1).

[0219] R6: The compound represented by the following formula [R6].

[0220]

[0221]

[0222]

[0223]

[0224] (Photoradical initiator)

[0225] P1: 1-Hydroxycyclohexylphenyl ketone (IGMresins, Omnirad 184).

[0226] (Methacrylic acid monomer)

[0227] A1~A3: Compounds represented by the formulas (A1)~(A3) below.

[0228]

[0229] (additive)

[0230] B1: The compound shown in the following formula (B1) (compound (B)).

[0231]

[0232] C1~C5: The compounds represented by the formulas (C1)~(C5) below (compound (C)).

[0233]

[0234] (Diamine)

[0235] D1: 3,5-Diaminobenzoic acid.

[0236] D2: 1,3-Diamino-4-{4-[trans-4-(trans-4-n-pentylcyclohexyl)cyclohexyl]phenoxy}benzene.

[0237]

[0238] (Tetracarboxylic acid dianhydride)

[0239] E1: 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride.

[0240] E2: Bicyclo[3.3.0]octane-2,4,6,8-tetracarboxylic acid dianhydride.

[0241]

[0242] (amine compounds)

[0243] D3: 3-aminomethylpyridine.

[0244]

[0245] (solvent)

[0246] NMP: N-methyl-2-pyrrolidone.

[0247] BCS: Ethylene glycol monobutyl ether.

[0248] CHN: Cyclohexanone.

[0249] PGME: Propylene glycol monomethyl ether.

[0250] "Polymer Molecular Weight Determination"

[0251] The determination was performed using a room-temperature gel permeation chromatography (GPC) apparatus (GPC-101, manufactured by Showa Denko Corporation) and a column (KD-803 and KD-805 in series, manufactured by Showa Denko Corporation), as described below.

[0252] Column temperature: 50℃.

[0253] Eluent: N,N-dimethylformamide (as additives, lithium bromide monohydrate (LiBr·H2O) 30 mmol / L, anhydrous phosphoric acid (o-phosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 mL / L).

[0254] Flow rate: 1.0 mL / min.

[0255] Standard samples used for calibration curve preparation: TSK standard polyethylene oxide (molecular weight: approximately 900,000, 150,000, 100,000 and 30,000) (manufactured by TOSOH) and polyethylene glycol (molecular weight: approximately 12,000, 4,000 and 1,000) (manufactured by Polymer Laboratory).

[0256] "Determination of imidization rate of polyimide polymers"

[0257] 20 mg of polyimide powder was added to an NMR (nuclear magnetic resonance) sample tube (NMR standard sampling tube, φ5 (manufactured by Kusano Science Co., Ltd.)), followed by 0.53 ml of deuterated dimethyl sulfoxide (DMSO-d6, 0.05% by mass TMS (tetramethylsilane) mixture), and the solution was sonicated to dissolve it completely. The solution was then measured at 500 MHz using an NMR analyzer (JNW-ECA500, manufactured by NEC DATUM Co., Ltd.). Regarding the imidization rate, the proton originating from the structure that remained unchanged before and after imidization was identified as the reference proton. The peak integral value of this proton, along with the peak integral value of the proton originating from the NH group of the ammonium acid appearing around 9.5–10.0 ppm, was used to calculate the rate using the following formula.

[0258] Imidification rate (%) = (1 - α·x / y) × 100

[0259] (x is the proton peak integral value derived from the NH group of the ammonium acid, y is the peak integral value of the reference proton, and α is the ratio of the reference proton to the number of NH protons of the ammonium acid in the case of polyammonium (imidization rate of 0%).)

[0260] Synthesis of Methacrylic Acid Polymers

[0261] <Synthesis example 1>

[0262] A1 (2.44 g, 6.80 mmol), A2 (0.40 g, 1.70 mmol), and A3 (0.73 g, 8.50 mmol) were dissolved in CHN (21.0 g). After degassing and nitrogen repressurization using a diaphragm pump, AIBN (azobisisobutyronitrile, 0.14 g, 0.85 mmol) as a polymerization initiator was added, and degassing and nitrogen repressurization were performed again. Then, the mixture was reacted at 60 °C for 13 hours to obtain a solution of methacrylic acid polymer (1).

[0263] Synthesis of Polyimide-based Polymers

[0264] <Synthesis example 2>

[0265] E2 (5.35 g, 21.4 mmol), D2 (3.72 g, 8.6 mmol), and D1 (3.04 g, 20.0 mmol) were mixed in NMP (36.3 g) and reacted at 80 °C for 5 hours. Then, E1 (1.28 g, 6.5 mmol) and NMP (3.86 g) were added, and the mixture was reacted at 40 °C for 6 hours to obtain a polyamic acid solution with a resin solids concentration of 25.0% by mass.

[0266] NMP was added to the obtained polyamic acid solution (20.0 g), diluted to 6% by mass, and then acetic anhydride (4.50 g) and pyridine (3.30 g) were added as imidization catalysts. The reaction was carried out at 90 °C for 3 hours. The reaction solution was then added to methanol (400 mL), and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100 °C to obtain polyimide powder. The imidization rate of this polyimide was 80%, the number average molecular weight was 19,600, and the weight average molecular weight was 49,100.

[0267] NMP (11.3 g) was added to the obtained polyimide powder (2.0 g), and the mixture was stirred at 70 °C for 24 hours to dissolve it. D3 (5.0% by mass NMP solution, 2.0 g) was added to the solution, and the mixture was stirred at 70 °C for 15 hours to obtain a solution of polyimide (1).

[0268] Manufacturing of liquid crystal alignment agents

[0269] The following describes a manufacturing example of a liquid crystal alignment agent. This liquid crystal alignment agent is also used in the fabrication and evaluation of liquid crystal elements.

[0270] <Example 1>

[0271] Additives B1 (0.03 g), C1 (0.03 g), CHN (1.3 g), and PGME (4.2 g) were added to a solution (2.0 g) of the methacrylic polymer (1) obtained in Synthesis Example 1, and stirred at room temperature to obtain liquid crystal alignment agent (1). It was confirmed that the liquid crystal alignment agent was a homogeneous solution without any abnormalities such as turbidity or precipitation.

[0272] <Example 2>

[0273] Additives B1 (0.03 g), C2 (0.03 g), CHN (1.3 g), and PGME (4.2 g) were added to a solution (2.0 g) of the methacrylic polymer (1) obtained in Synthesis Example 1, and stirred at room temperature to obtain a liquid crystal alignment agent (2). It was confirmed that the liquid crystal alignment agent was a homogeneous solution without any abnormalities such as turbidity or precipitation.

[0274] <Example 3>

[0275] Additives B1 (0.03 g), C3 (0.03 g), CHN (1.3 g), and PGME (4.2 g) were added to a solution (2.0 g) of the methacrylic polymer (1) obtained in Synthesis Example 1, and stirred at room temperature to obtain a liquid crystal alignment agent (3). It was confirmed that the liquid crystal alignment agent was a homogeneous solution without any abnormalities such as turbidity or precipitation.

[0276] <Example 4>

[0277] Additives B1 (0.03 g), C4 (0.03 g), CHN (1.3 g), and PGME (4.2 g) were added to a solution (2.0 g) of the methacrylic polymer (1) obtained in Synthesis Example 1, and stirred at room temperature to obtain a liquid crystal alignment agent (4). It was confirmed that the liquid crystal alignment agent was a homogeneous solution without any abnormalities such as turbidity or precipitation.

[0278] <Example 5>

[0279] Additives B1 (0.03 g), C5 (0.03 g), CHN (1.3 g), and PGME (4.2 g) were added to a solution (2.0 g) of the methacrylic polymer (1) obtained in Synthesis Example 1, and stirred at room temperature to obtain a liquid crystal alignment agent (5). It was confirmed that the liquid crystal alignment agent was a homogeneous solution without any abnormalities such as turbidity or precipitation.

[0280] <Example 6>

[0281] Additives B1 (0.046 g), C1 (0.046 g), NMP (1.9 g), and BCS (5.0 g) were added to a solution (3.06 g) of polyimide (1) obtained in Synthesis Example 2. The mixture was stirred at 25°C for 2 hours to obtain a liquid crystal alignment agent (6). It was confirmed that no abnormalities such as turbidity or precipitation were found in the liquid crystal alignment agent, and it was a homogeneous solution.

[0282] <Example 7>

[0283] Additives B1 (0.046 g), C2 (0.046 g), NMP (1.9 g), and BCS (5.0 g) were added to a solution (3.06 g) of polyimide (1) obtained in Synthesis Example 2. The mixture was stirred at 25°C for 2 hours to obtain a liquid crystal alignment agent (7). It was confirmed that no abnormalities such as turbidity or precipitation were found in the liquid crystal alignment agent, and it was a homogeneous solution.

[0284] <Comparative Example 1>

[0285] CHN (1.3 g) and PGME (4.2 g) were added to a solution (2.0 g) of the methacrylic polymer (1) obtained in Synthesis Example 1, and the mixture was stirred at room temperature to obtain a liquid crystal alignment agent (8). It was confirmed that the liquid crystal alignment agent was a homogeneous solution without any abnormalities such as turbidity or precipitation.

[0286] <Comparative Example 2>

[0287] Additives B1 (0.03 g), CHN (1.3 g), and PGME (4.2 g) were added to a solution (2.0 g) of the methacrylic polymer (1) obtained in Synthesis Example 1, and stirred at room temperature to obtain a liquid crystal alignment agent (9). It was confirmed that the liquid crystal alignment agent was a homogeneous solution without any abnormalities such as turbidity or precipitation.

[0288] <Comparative Example 3>

[0289] Additives C1 (0.03 g), CHN (1.3 g), and PGME (4.2 g) were added to a solution (2.0 g) of the methacrylic polymer (1) obtained in Synthesis Example 1, and stirred at room temperature to obtain a liquid crystal alignment agent (10). It was confirmed that the liquid crystal alignment agent was a homogeneous solution without any abnormalities such as turbidity or precipitation.

[0290] <Comparative Example 4>

[0291] Additives B1 (0.03 g), A3 (0.03 g), CHN (1.3 g), and PGME (4.2 g) were added to a solution (2.0 g) of the methacrylic polymer (1) obtained in Synthesis Example 1, and stirred at room temperature to obtain a liquid crystal alignment agent (11). It was confirmed that the liquid crystal alignment agent was a homogeneous solution without any abnormalities such as turbidity or precipitation.

[0292] <Comparative Example 5>

[0293] NMP (1.9 g) and BCS (5.0 g) were added to a solution (3.06 g) of polyimide (1) obtained in Synthesis Example 2, and the mixture was stirred at 25 °C for 2 hours to obtain a liquid crystal alignment agent (12). It was confirmed that the liquid crystal alignment agent was a homogeneous solution without any abnormalities such as turbidity or precipitation.

[0294] <Comparative Example 6>

[0295] Additives B1 (0.046 g), NMP (1.9 g), and BCS (5.0 g) were added to a solution (3.06 g) of polyimide (1) obtained in Synthesis Example 2, and the mixture was stirred at 25°C for 2 hours to obtain a liquid crystal alignment agent (13). It was confirmed that the liquid crystal alignment agent was a homogeneous solution without any abnormalities such as turbidity or precipitation.

[0296] The compositions of the liquid crystal alignment agents obtained in the Examples and Comparative Examples are shown in Table 1. It should be noted that the values ​​in parentheses for additives represent the content (parts by mass) relative to 100 parts by mass of each polymer.

[0297] [Table 1]

[0298]

[0299] <Fabrication of dimming layer forming material (A)>

[0300] R1 (0.90 g), R2 (1.50 g), R3 (1.50 g), R4 (0.30 g), R5 (0.30 g), and R6 (0.50 g) were mixed and stirred at 25°C for 6 hours to prepare a solution of the polymerizable compound. Then, the prepared solution of the polymerizable compound, L1 (4.0 g), and P1 (0.10 g) were mixed and stirred at 25°C for 6 hours to obtain the dimming layer forming material (A).

[0301] "Fabrication and Evaluation of Optical Properties of Liquid Crystal Components"

[0302] Liquid crystal alignment agents from Examples 1-7 and Comparative Examples 1-6 were pressurized and filtered using a membrane filter with a pore size of 1 μm to fabricate liquid crystal elements. Specifically, the liquid crystal alignment agent was coated onto the ITO surface of a PET (polyethylene terephthalate) substrate (length: 150 mm, width: 150 mm, thickness: 0.2 mm) with ITO electrodes, which had been cleaned with pure water, using a rod coater. The substrate was then heated at 100°C for 5 minutes on a heating plate, followed by heating at 120°C for 2 minutes in a thermal cycling cleanroom oven, resulting in an ITO substrate with an alignment film thickness of 100 nm. It should be noted that no coating defects such as streaks or edge shrinkage were observed in the coating films using the liquid crystal alignment agents from Examples 1-7, resulting in uniform coating films. Two ITO substrates with alignment films were prepared, and a spacer with a thickness of 6 μm was coated onto the alignment film surface of one of the substrates. Then, the dimming layer forming material (A) described above is dropped onto the alignment film surface of the substrate coated with spacers using the ODF method. Next, the substrates are bonded together with their alignment film interfaces facing each other to obtain the liquid crystal element before processing.

[0303] The liquid crystal element before treatment was irradiated with ultraviolet light using an ultraviolet irradiation device with a light source equipped with an ultraviolet light-emitting diode, at a wavelength of 365 nm, an ultraviolet irradiance of 4 mW, and an irradiation time of 250 seconds. The temperature inside the irradiation device was controlled at 25°C. Thus, a liquid crystal element (reverse-type element) was obtained.

[0304] Evaluation of optical properties (transparency and scattering properties)

[0305] The transparency without applied voltage was evaluated by measuring the haze (turbidity, also known as HAZE) of the liquid crystal element in the absence of applied voltage. Specifically, the haze was measured using a BYK haze-gardi (TETSUTANI). For evaluation purposes, lower haze indicates better transparency.

[0306] The evaluation of the scattering characteristics under applied voltage was performed by applying an AC drive of 48V to the liquid crystal element under the same conditions as described above, and measuring the haze. In terms of evaluation, the higher the haze, the better the scattering characteristics.

[0307] The evaluation results of the optical properties are shown in Table 2.

[0308] Evaluation of the adhesion between the liquid crystal layer and the alignment film

[0309] The fabricated liquid crystal element was tested in a small benchtop testing machine, Shimadzu Corporation's EZ-SX. The lower substrate was fixed to the worktable, and the end of the upper substrate was fixed. The upper substrate was then stretched upwards, and the peel strength (N / 25mm) between the liquid crystal layer and the alignment film was measured. The higher this value, the better the adhesion in this evaluation.

[0310] The evaluation results of the fit are shown in Table 2.

[0311] [Table 2]

[0312]

[0313] As shown in Table 2, the examples using liquid crystal alignment films obtained by liquid crystal alignment agents containing compounds (B) and (C) as additives showed improved adhesion between the liquid crystal layer and the alignment film, and better optical properties, compared to the comparative examples using liquid crystal alignment films obtained by liquid crystal alignment agents not containing compounds (B) and / or (C) as additives.

[0314] Explanation of reference numerals in the attached figures:

[0315] 100: Liquid crystal element; 11: First substrate; 17: Second substrate; 14: Dimming layer; 13, 15: Liquid crystal alignment film; 12, 16: Transparent electrode.

Claims

1. A liquid crystal alignment agent, characterized in that, It contains components A, B, and C as described below. Component A: At least one polymer A selected from the group consisting of polymer A-1 having a monomer a-1 with a polymerizable unsaturated bond, polyimide precursor A-2 having a carboxyl group, and polyimide A-3 having a carboxyl group, wherein the polymer A-1 has a carboxyl group. Component B: Compound B with two or more epoxy groups in its molecule and a molecular weight of less than 2000; Component C: A compound C having a molecular weight of less than 2000 and having at least one carboxyl group and one polymerizable unsaturated bond within its molecule, wherein compound C is at least one selected from the group consisting of C-1 to C-4: C-1 is a carboxyl-containing (meth)acrylate compound having at least one cyclic group Cy selected from the group consisting of alicyclic hydrocarbon groups having 4 to 40 carbon atoms and aromatic hydrocarbon groups having 6 to 40 carbon atoms. A vinyl-containing aromatic carboxylic acid C-2 having the cyclic group Cy; Maleimide C-3 containing a carboxyl group and having the cyclic group Cy; and C-4 is a carboxyl-containing (meth)acrylamide compound having the cyclic group Cy.

2. The liquid crystal alignment agent according to claim 1, wherein, The polymer A-1 is obtained by polymerizing a monomer having a carboxyl group and a polymerizable unsaturated bond.

3. The liquid crystal alignment agent according to claim 1, wherein, The monomer a-1 having polymerizable unsaturated bonds is selected from at least one group consisting of (meth)acrylic acid compounds, (meth)acrylamide compounds, aromatic vinyl compounds, conjugated diene compounds, compounds containing maleimide groups, α-methylene-γ-butyrolactone compounds, and vinyl compounds.

4. The liquid crystal alignment agent according to claim 1, wherein, The compound B is selected from at least one of the following groups: compound B-1, which does not contain a tertiary nitrogen atom, has two or more epoxy groups, and has a molecular weight of less than 2000; and compound B-2, which contains a tertiary nitrogen atom, has two or more epoxy groups, and has a molecular weight of less than 2000.

5. The liquid crystal alignment agent according to claim 1, wherein, The polymer A-1 is synthesized using a compound represented by the following formula (S-mA), which does not include monomers having carboxyl groups and polymerizable unsaturated bonds. In the formula, P represents (meth)acryloyloxy, styryl, vinyloxy CH2=CH-O-, maleimide, or α-methylene-γ-butyrolactone structure. X represents a single bond, -(CH2) a -, -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -COO-, -OCO-, -CH=CH-COO-CH2-Ak- or - ((CH2) a1 -A1) m1 -, the - (CH2) a In the - group, a is an integer from 1 to 15; in the -CH=CH-COO-CH2-Ak- group, Ak represents an alkylene group with 1 to 17 carbon atoms, and a portion of the methylene group in Ak is optionally replaced by -O-, -CONH-, -COO-, or -OCO-. When Ak is a methylene group, all methylene groups are optionally replaced by -O-, -CONH-, -COO-, or -OCO-. a1 -A1) m1 In the given text, a1 is an integer from 1 to 15, A1 represents an oxygen atom or -COO-, and m1 is an integer from 1 to 2; when m1 is 2, multiple a1 and A1 independently possess the aforementioned definitions. J represents a monovalent organic group having at least one group selected from the group consisting of an alicyclic hydrocarbon group having 4 to 40 carbon atoms and an aromatic hydrocarbon group having 6 to 40 carbon atoms, wherein at least one hydrogen atom of the alicyclic hydrocarbon group and the aromatic hydrocarbon group is substituted by a substituent selected from the group consisting of a halogen atom, a halogen-containing alkyl group, a halogen-containing alkoxy group, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, an alkenyl group having 3 to 10 carbon atoms, and a heteroatom-containing group formed by the interruption of the carbon-carbon bond of any methylene group of an alkyl group having halogen atom, an alkoxy group having 3 to 10 carbon atoms, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, and an alkenyl group having 3 to 10 carbon atoms; furthermore, in the case where P is (meth)acryloyloxy, vinyloxy CH2=CH-O- or maleimide, X represents a single bond or a group bonded to P via a carbon atom.

6. The liquid crystal alignment agent according to claim 1, wherein, At least one polymer selected from the group consisting of the polyimide precursor A-2 and the polyimide A-3 is a polymer obtained by reacting a diamine component with a tetracarboxylic acid component, wherein the diamine component contains an aromatic diamine having a "-X-J" group on its side chain. In the group "-X-J", X represents a single bond and -(CH2). a -, -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -COO-, -OCO-, -CH=CH-COO-CH2-Ak- or - ((CH2) a1 -A1) m1 -, the - (CH2) a In the - group, a is an integer from 1 to 15; in the -CH=CH-COO-CH2-Ak- group, Ak represents an alkylene group with 1 to 17 carbon atoms, and a portion of the methylene group in Ak is optionally replaced by -O-, -CONH-, -COO-, or -OCO-. When Ak is a methylene group, all methylene groups are optionally replaced by -O-, -CONH-, -COO-, or -OCO-. a1 -A1) m1 In the given text, a1 is an integer from 1 to 15, A1 represents an oxygen atom or -COO-, and m1 is an integer from 1 to 2; when m1 is 2, multiple a1 and A1 independently possess the aforementioned definitions. J represents a monovalent organic group having at least one group selected from the group consisting of an alicyclic hydrocarbon group having 4 to 40 carbon atoms and an aromatic hydrocarbon group having 6 to 40 carbon atoms, wherein at least one hydrogen atom of the alicyclic hydrocarbon group and the aromatic hydrocarbon group is substituted by a substituent selected from the group consisting of a halogen atom, a halogen-containing alkyl group, a halogen-containing alkoxy group, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, an alkenyl group having 3 to 10 carbon atoms, and a heteroatom-containing group formed by the interruption of the carbon-carbon bond of any methylene group of an alkyl group having halogen atom, an alkoxy group having halogen atom, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, and an alkenyl group having 3 to 10 carbon atoms.

7. A liquid crystal alignment film formed using a liquid crystal alignment agent as described in any one of claims 1 to 6.

8. A liquid crystal element comprising a liquid crystal alignment film as described in claim 7.

9. A method for manufacturing a polymer-dispersed liquid crystal element, comprising the following steps 1 to 4, Step 1: The process of applying the liquid crystal alignment agent as described in any one of claims 1 to 6 to one or both of a pair of substrates with electrodes. Step 2: A step of firing the coating film formed on the substrate by step 1; Step 3: The process of preparing the dimming layer forming material; Step 4: The process of polymerizing the configured dimming layer forming material to form a dimming layer comprising a polymer phase and a liquid crystal phase.

Images