JP2006078830A - Liquid crystal element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal element having improved display performance. <P>SOLUTION: The liquid crystal element has a substrate and a liquid crystal layer supported by the substrate, wherein the substrate comprises a silane coupling agent expressed with a general formula (1) fixed thereto with a covalent bond. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention belongs to the technical field of liquid crystal elements including a substrate whose surface is modified with a specific silane coupling agent.

  Research is being actively conducted to modify the substrate with a silane coupling agent to control the physical properties of the substrate surface and apply it to a functional material. As such silane coupling agents, the following silane coupling agents 1 and 2 in which sites having positive dielectric anisotropy are linked have been reported (Non-Patent Documents 1 and 2). The following silane coupling agent 1 has been reported to be fixed on a mica substrate.

  There is also a report on a liquid crystal element using an electrode substrate surface-treated with a silane coupling agent. The silane coupling agents used are octadecyltriethoxysilane (Patent Documents 1 and 2) and silane coupling agent 3 respectively. (Non-patent Document 3).

  However, when a conventional silane coupling agent is used, it may still be insufficient for controlling the alignment of liquid crystal molecules, and an improvement is desired.

Thin Solid Films, 323, 42-52, 1998 Helv. Chim. Acta. 62, 2547, 1979 JP 2002-148600 A JP 2000-321562 A Angew. Chem. Int. Ed. 42, 1812, 2003

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a novel substrate and liquid crystal element having unprecedented characteristics. Another object of the present invention is to provide a substrate that contributes to an improvement in display performance when used in a liquid crystal element, and a liquid crystal element with improved display performance.

  Conventionally, as a silane coupling agent for modifying a substrate, a silane coupling agent having a long-chain alkyl group and a silane coupling agent substituted with an unsubstituted benzene ring or naphthalene ring have been known. These substituents have low responsiveness to an electric field, and when a liquid crystal element using the substrate is constructed, the orientation of the liquid crystal is almost the same when no voltage is applied and when a voltage is applied. However, as a result of intensive studies, the present inventor produced a guest-host type liquid crystal device using a substrate surface-treated with a silane coupling agent in which specific substitution mode sites were linked, and the display contrast ratio was improved. The present inventors have obtained knowledge that an unexpected effect can be obtained, and have further studied based on this knowledge to complete the present invention.

Means for solving the above-mentioned problems are as follows.
[1] A liquid crystal element having a substrate and a liquid crystal layer supported by the substrate, wherein the substrate is a substrate to which a silane coupling agent represented by the following general formula (1) is fixed by a covalent bond:

式中、Ｘ¹、Ｘ²、Ｘ³及びＸ⁴は各々水素原子又は置換基を表し、Ｒ¹はニトロ基、ハロゲン原子、シアノ基、又は置換もしくは無置換のアルコキシ基を表し、Ｌ¹は２価の連結基を表し、Ｙ¹、Ｙ²及びＹ³は各々置換基を表すが、少なくとも一つは離脱基である。
［２］ 前記一般式（１）中、Ｘ¹、Ｘ²、Ｘ³及びＸ⁴が水素原子であり、Ｒ¹がシアノ基である［１］の液晶素子。
［３］ ゲストホスト方式の液晶素子である［１］又は［２］の液晶素子。
［４］ 前記シランカップリング剤が共有結合により固定された基板が、透明電極基板である［１］〜［３］のいずれかの液晶素子。

In the formula, each of X ¹ , X ² , X ³ and X ⁴ represents a hydrogen atom or a substituent, R ¹ represents a nitro group, a halogen atom, a cyano group, or a substituted or unsubstituted alkoxy group, and L ¹ represents A divalent linking group is represented, and Y ¹ , Y ² and Y ³ each represent a substituent, but at least one is a leaving group.
[2] The liquid crystal element according to [1], wherein, in the general formula (1), X ¹ , X ² , X ³ and X ⁴ are hydrogen atoms and R ¹ is a cyano group.
[3] The liquid crystal element according to [1] or [2], which is a guest-host type liquid crystal element.
[4] The liquid crystal element according to any one of [1] to [3], wherein the substrate on which the silane coupling agent is fixed by a covalent bond is a transparent electrode substrate.

  A liquid crystal device using the substrate of the present invention in which a specific silane coupling agent is fixed by a covalent bond exhibits a high contrast ratio.

BEST MODE FOR CARRYING OUT THE INVENTION

  Hereinafter, the present invention will be described in detail. In the present specification, “to” indicates a range including the numerical values described before and after the minimum and maximum values, respectively.

  The liquid crystal element of the present invention has a substrate on which a silane coupling agent represented by the following general formula (1) is fixed by a covalent bond.

In the formula, X ¹ , X ² , X ³ and X ⁴ each represent a hydrogen atom or a substituent. The following substituent group V is mentioned as a substituent.
Substituent group V
Nitro group, cyano group, halogen atom (chloro atom, bromo atom, fluorine atom, iodine atom), mercapto group, carboxy group, phosphate group, sulfo group, hydroxy group, 1 to 10 carbon atoms, preferably 2 to 2 carbon atoms 8, more preferably a carbamoyl group having 2 to 5 carbon atoms (for example, methylcarbamoyl, ethylcarbamoyl, morpholinocarbonyl), 0 to 10 carbon atoms, preferably 2 to 8 carbon atoms, more preferably a sulfamoyl group having 2 to 5 carbon atoms. (Eg, methylsulfamoyl, ethylsulfamoyl, piperidinosulfonyl), an alkoxy group having 1 to 20, preferably 1 to 10, and more preferably 1 to 8 carbon atoms (eg, trifluoromethoxy, methoxy , Ethoxy, 2-methoxyethoxy, 2-phenylethoxy), 6 to 20 carbon atoms, preferably An aryloxy group having 6 to 12 prime atoms, more preferably 6 to 10 carbon atoms (for example, phenoxy, p-methylphenoxy, p-chlorophenoxy, naphthoxy), 1 to 20 carbon atoms, preferably 2 to 12 carbon atoms, and more preferably Is an acyl group having 2 to 8 carbon atoms (for example, acetyl, benzoyl, trichloroacetyl), an acyloxy group having 1 to 20, preferably 2 to 12, and more preferably 2 to 8 carbon atoms (for example, acetyloxy, benzoyl). Oxy), an acylamino group having 1 to 20 carbon atoms, preferably 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms (for example, acetylamino), 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably Is a sulfonyl group having 1 to 8 carbon atoms (for example, methanesulfonyl, ethanesulfonyl, benzenesulfonyl), 1 to carbon atoms 0, preferably 1 to 10 carbon atoms, more preferably 1 to 8 carbon sulfinyl groups (eg methanesulfinyl, ethanesulfinyl, benzenesulfinyl), 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably A sulfonylamino group having 1 to 8 carbon atoms (for example, methanesulfonylamino, ethanesulfonylamino, benzenesulfonylamino), 0 to 20 carbon atoms, preferably 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms substituted or unsubstituted. A substituted amino group (for example, methylamino, dimethylamino, benzylamino, anilino, diphenylamino), an ammonium group having 0 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 6 carbon atoms (for example, trimethylammonium group) , Triethylammonium), C0-15, preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon hydrazino groups (for example, trimethylhydrazino group), 1 to 15 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon ureido groups. (For example, ureido group, N, N-dimethylureido group), carbon number 1-15, preferably carbon number 1-10, more preferably carbon number 1-6 imide group (for example, succinimide group), carbon number 1-20 An alkylthio group having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms (for example, methylthio, ethylthio, propylthio), 6 to 20 carbon atoms, preferably 6 to 12 carbon atoms, and more preferably 6 to 6 carbon atoms. 10 arylthio groups (for example, phenylthio, p-methylphenylthio, p-chlorophenylthio, 2-pyridylthio, naphthylthio), 2-20 carbon atoms, Or an alkoxycarbonyl group having 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms (for example, methoxycarbonyl, ethoxycarbonyl, 2-benzyloxycarbonyl), 6 to 20 carbon atoms, preferably 6 to 12 carbon atoms, Preferably an aryloxycarbonyl group having 6 to 10 carbon atoms (for example, phenoxycarbonyl), an unsubstituted alkyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms (for example, methyl, ethyl). , Propyl, butyl), a substituted alkyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms (for example, hydroxymethyl, trifluoromethyl, benzyl, carboxyethyl, ethoxycarbonylmethyl, Acetylaminomethyl, also here having 2 to 18 carbon atoms, preferably 3 to 3 carbon atoms 0, more preferably an unsaturated hydrocarbon group having 3 to 5 carbon atoms (for example, vinyl group, ethynyl group 1-cyclohexenyl group, benzylidine group, benzylidene group) is also included in the substituted alkyl group}, 6 carbon atoms -20, preferably 6-15, more preferably 6-10, substituted or unsubstituted aryl groups (eg phenyl, naphthyl, p-carboxyphenyl, p-nitrophenyl, 3,5-dichlorophenyl, p -Cyanophenyl, m-fluorophenyl, p-tolyl), a substituted or unsubstituted heterocyclic group having 1 to 20 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 4 to 6 carbon atoms (for example, pyridyl, 5 -Methylpyridyl, thienyl, furyl, morpholino, tetrahydrofurfuryl). Alternatively, a structure in which a ring (aromatic or non-aromatic hydrocarbon ring or heterocyclic ring such as a benzene ring, a naphthalene ring, an anthracene ring, or a quinoline ring) is condensed can be used.
X ¹ , X ² , X ³ and X ⁴ are preferably a hydrogen atom, an alkyl group or an aryl group. Two or more of X ^{1 to} X ⁴ are preferably hydrogen atoms, preferably three or more are hydrogen atoms, and particularly preferably all are hydrogen atoms.

R ¹ represents a nitro group, a halogen atom, a cyano group, or a substituted or unsubstituted alkoxy group. Specific examples of the substituent of the alkoxy group include the above substituent group V. The alkoxy group is preferably unsubstituted. R ¹ is preferably a halogen atom or a cyano group.

L ¹ represents a divalent linking group and is preferably composed of an atomic group composed of at least one kind of atom selected from a carbon atom, a nitrogen atom, a sulfur atom and an oxygen atom. Examples of the divalent linking group include alkylene groups having 1 to 20 carbon atoms (for example, methylene, ethylene, propylene, butylene, pentylene, cyclohexyl-1,4-diyl), and alkenylene groups having 2 to 20 carbon atoms (for example, ethenylene). ), An alkynylene group having 2 to 20 carbon atoms (for example, ethynylene), an amide group, an ether group, an ester group, a sulfoamide group, a sulfonic acid ester group, a ureido group, a sulfonyl group, a sulfinyl group, a thioether group, a carbonyl group, -NR A group (wherein R represents a hydrogen atom, an alkyl group or an aryl group), an azo group, an azoxy group, a heterocyclic divalent group (for example, a piperazine-1,4-diyl group) and an arylene group (phenylene group, A divalent linking group having 0 to 60 carbon atoms constituted by combining one or more naphthylene groups). That. The divalent linking group represented by L ¹ is preferably an alkylene group, alkenylene group, alkynylene group, ether group, thioether group, amide group, ertel group, carbonyl group, arylene group, or a combination thereof. Although the example of the coupling group which combined at least 2 sorts chosen from these groups is shown below, it is not limited to these.

式中、ｐ及びｑは各々、１〜２０の整数であり、好ましくは１〜１０の整数であり、より好ましくは２〜１０の整数である。また、前記具体例中、ベンゼン環がナフタレン環又はテトラヒドロナフタレン環に置き換わった連結基も具体例として挙げられる。

In the formula, each of p and q is an integer of 1 to 20, preferably an integer of 1 to 10, and more preferably an integer of 2 to 10. In addition, in the specific examples, a linking group in which a benzene ring is replaced with a naphthalene ring or a tetrahydronaphthalene ring is also given as a specific example.

The linking group L ¹ may further have a substituent, and examples of the substituent include the substituent group V.

Y ¹ , Y ² and Y ³ each represent a substituent. Examples of the substituent represented by Y ¹ , Y ^2, and Y ³ include the substituents described in Substituent Group V above. However, at least one of Y ¹ , Y ² and Y ³ is a leaving group. A leaving group is defined as a chemical species that is expelled by an attacking nucleophile and is described on page 320 of "Organic Chemistry (top)" (McMurry, Ito, Kodama et al., Tokyo Chemical Dojin, 1987). Details are described. Examples of the leaving group include an alkoxy group, an aryloxy group, a halogen atom, an alkyl sulfonate ester, an aryl sulfonate ester, and an amino group. The leaving group represented by Y ¹ , Y ² and Y ³ is preferably an alkoxy group or an aryloxy group, and particularly preferably an alkoxy group. The substituents represented by Y ¹ , Y ² and Y ³ are preferably alkoxy groups, aryloxy groups, alkyl groups or aryl groups, and at least one of them is an alkoxy group or aryloxy group which is a leaving group, Are more preferably leaving groups, and more preferably all are alkoxy groups that are leaving groups. One or two of Y ¹ , Y ² and Y ³ may be a substituent bonded to Si at L ¹ .

  Although the specific example of the silane coupling agent represented by the said General formula (1) is shown below, of course, this invention is not limited to these.

  In a narrow sense, a silane coupling agent has an organic functional group and a detachable or hydrolyzable group bonded to silicon in the molecule, and these groups react with an organic material and an inorganic material, respectively. In this specification, the term “reagent for binding an organic material to an inorganic material” may be used. However, in this specification, a broad term includes any reagent having an organic group and a leaving group bonded to silicon in the molecule. Used in meaning. Therefore, in the present specification, the silane coupling agent does not necessarily have an organic functional group that can react with an organic material, and includes a reagent that is not expected to react with the organic material. Used in. The silane coupling agent can be synthesized by combining various conventionally known reactions. For example, it can be synthesized using the method described in “Rubber Material Compounding Technology and Nanocomposite” (Shinzo Kikutani, Toshio Nishi, Koichi Yamaguchi, Mitsuo Akiba, CMC, 2003).

The substrate used in the present invention is a substrate on which the silane coupling agent is fixed by a covalent bond. The silane coupling agent can be fixed to the substrate by a covalent bond using a silane coupling reaction. Each reaction will be described in detail below.
1. Silane coupling reaction By causing the silane coupling agent to undergo a silane coupling reaction with an inorganic material, the surface of the inorganic material can be modified with an organic group having a negative dielectric anisotropy. For example, it can be used for surface modification of a substrate made of an inorganic material such as glass, metal, or metal oxide. Silane coupling reaction is generally a functional group containing silicon, such as alkoxysilyl and aryloxysilyl, which is covalently coupled to inorganic materials such as glass via hydrolysis and dehydration condensation reactions. Means a reaction to The functional group capable of silane coupling reaction contained in the silane coupling agent of the present invention is preferably an alkoxysilyl group, more preferably a trimethoxysilyl group, a triethylsilyl group, or a tripropoxysilyl group.

The target with which the silane coupling agent reacts is not particularly limited, but is preferably capable of reacting with an inorganic material, more preferably glass or an electrode material (more preferably a transparent electrode material made of a metal oxide or the like). Preferably there is. The silane coupling reaction is preferably allowed to proceed by adding an acid or alkali as a catalyst to an alcohol and an aqueous solution containing a silane coupling agent as a raw material. The ratio of alcohol to silane coupling agent may be any, but is preferably silane coupling agent: alcohol = 1: 0.1 to 1: 100, and particularly preferably 1: 1 to 1: The range is 10. Although there is no restriction | limiting in particular about alcohol used for reaction, Methanol and ethanol are preferable. The ratio of water to the silane coupling agent may be any, but is preferably silane coupling agent: water = 1: 0.1 to 1: 1000, and particularly preferably 1: 1 to 1: A range of 100. Although there is no restriction | limiting in particular about the acid used as a catalyst, For example, hydrochloric acid, a sulfuric acid, phosphoric acid, organic sulfonic acid etc. are mentioned. Although there is no restriction | limiting in particular about the alkali used as a catalyst, For example, ammonia, sodium hydroxide, potassium hydroxide, tertiary nitrogen bases (triethylamine etc.), nitrogen-containing heterocyclic rings (pyridine etc.), etc. are mentioned. The ratio of the catalyst to the silane coupling agent may be any, but is preferably silane coupling agent: catalyst = 1: 1 × 10 ⁻⁶ to 1: 1, particularly preferably 1: 1 ×. It is in the range of 10 ⁻⁵ to 1: 1 × 10 ⁻³ .

  Although there is no restriction | limiting in particular about reaction temperature, Preferably it is the range of 0 to 300 degreeC, Most preferably, it is the range of 20 to 200 degreeC. Although there is no restriction | limiting in particular also about reaction time, Preferably it is 1 second-100 hours, Especially preferably, it is the range of 1 minute-50 hours.

2. Sol-gel reaction By carrying out the sol-gel reaction of the silane coupling agent, a gel in which the organic groups in the general formula (1) are linked can be prepared. Here, the “sol-gel reaction” is generally a reaction in which a solution of a metal organic compound is used as a raw material, and the solution is made into a sol in which fine particles of metal oxide or hydroxide are dissolved by hydrolysis and polymerization. It is the reaction characterized by making it gelatinize by making it progress further. Generally, materials prepared by a sol-gel reaction include SiO ₂ , TiO ₂ , ZrO ₂ , Al ₂ O ₃ , BaTiO, LiNbO ₃ , KTaO _{3 and the} like. Using a solution of the silane coupling agent as a raw material, a gel in which SiO ₂ and an organic group are combined can be prepared by a sol-gel reaction.

  The conditions for the sol-gel reaction are not particularly limited, but the conditions described below are preferable. It is preferable to proceed hydrolysis by adding an acid or alkali as a catalyst to the alcohol and aqueous solution containing the silane coupling agent of the present invention as a raw material. The ratio of the alcohol with respect to the silane coupling agent may be any, but the mass ratio is preferably silane coupling agent: alcohol = 1: 0.1 to 1: 100, particularly preferably 1: 1. It is in the range of ˜1: 10. Any alcohol may be used, but methanol and ethanol are preferred. The ratio of water to the silane coupling agent may be any, but is preferably silane coupling agent: water = 1: 0.1 to 1: 1000, and particularly preferably 1: 1 to 1: A range of 100.

  Various catalyst compounds may be used in the sol liquid obtained by the progress of hydrolysis for the purpose of promoting the hydrolysis / partial condensation reaction. The catalyst used is not particularly limited, and an appropriate amount may be used according to the constituent components of the used sol solution. In general, the following compounds (c1) to (c5) are effective, and a necessary amount of a preferable compound can be added from these compounds. In addition, in the following groups (c1) to (c5), two or more kinds can be appropriately selected and used in combination as long as the mutual promoting effects are not inhibited.

(C1) Organic or inorganic acids Examples of inorganic acids include hydrochloric acid, hydrogen bromide, hydrogen iodide, sulfuric acid, sulfurous acid, nitric acid, nitrous acid, phosphoric acid, and phosphorous acid. Examples of organic acid compounds include carboxylic acids (formic acid, acetic acid, Propionic acid, butyric acid, succinic acid, cyclohexanecarboxylic acid, octanoic acid, maleic acid, 2-chloropropionic acid, cyanoacetic acid, trifluoroacetic acid, perfluorooctanoic acid, benzoic acid, pentafluorobenzoic acid, phthalic acid, etc.), sulfone Acids (methanesulfonic acid, ethanesulfonic acid, trifluoromethanesulfonic acid), p-toluenesulfonic acid, pentafluorobenzenesulfonic acid, etc.), phosphoric acid / phosphonic acids (phosphoric acid dimethyl ester, phenylphosphonic acid, etc.), Lewis acids (three fluorocarbons) Boron bromide etherate, scandium triflate, alkyl titanic acid, And alumina) and heteropolyacids (phosphomolybdic acid, phosphotungstic acid, etc.).

(C2) Organic or inorganic base Examples of the inorganic base include sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, and ammonia. Examples of the organic base compound include amines (ethylenediamine, diethylenetriamine, triethylenetetramine). , Tetraethylenepentamine, triethylamine, dibutylamine, tetramethylethylenediamine, piperidine, piperazine, morpholine, ethanolamine, diazabicycloundecene, quinuclidine, aniline, pyridine, etc.), phosphines (triphenylphosphine, trimethylphosphine, etc.), Metal alkoxides (sodium methylate, potassium ethylate, etc.) can be mentioned.

(C3) Metal chelate compound As the metal chelate compound, tri-n-butoxyethyl acetoacetate zirconium, di-n-butoxybis (ethyl acetoacetate) zirconium, n-butoxy tris (ethyl acetoacetate) zirconium, tetrakis (n-propylacetate) Zirconium chelate compounds such as acetate) zirconium, tetrakis (acetylacetoacetate) zirconium, tetrakis (ethylacetoacetate) zirconium; diisopropoxy bis (ethylacetoacetate) titanium, diisopropoxy bis (acetylacetate) titanium, diiso Titanium chelate compounds such as propoxy bis (acetylacetone) titanium; diisopropoxyethyl acetoacetate aluminum; Diisopropoxyacetylacetonate aluminum, isopropoxybis (ethylacetoacetate) aluminum, isopropoxybis (acetylacetonate) aluminum, tris (ethylacetoacetate) aluminum, tris (acetylacetonato) aluminum, monoacetylacetonate bis (Ethyl acetoacetate) Aluminum chelate compounds such as aluminum can be mentioned. Among these metal chelate compounds, preferred are tri-n-butoxyethyl acetoacetate zirconium, diisopropoxybis (acetylacetonate) titanium, diisopropoxyethyl acetoacetate aluminum, and tris (ethyl acetoacetate) aluminum. . These metal chelate compounds can be used individually by 1 type or in mixture of 2 or more types. Moreover, the partial hydrolyzate of these metal chelate compounds can also be used.

(C4) Organometallic compound Although there is no restriction | limiting in particular as a preferable organometallic compound, An organic transition metal has high activity and is preferable. Of these, tin compounds are particularly preferred because of their good stability and activity. Specific examples of these compounds are (C ₄ H ₉ ) ₂ Sn (OCOC ₁₁ H ₂₃ ) ₂ , (C ₄ H ₉ ) ₂ Sn (OCOCH═CHCOOC ₄ H ₉ ) ₂ , (C ₈ H ₁₇ ) _2. Carboxylic acid type organotin compounds such as Sn (OCOC ₁₁ H ₂₃ ) ₂ , (C ₈ H ₁₇ ) ₂ Sn (OCOCH═CHCOOC ₄ H ₉ ) ₂ , Sn (OCOCC ₈ H ₁₇ ) ₂ ; (C ₄ H ₉ ) ₂ Sn (SCH ₂ COOC ₈ H ₁₇ ) ₂ , (C ₄ H ₉ ) ₂ Sn (SCH ₂ COOC ₈ H ₁₇ ) ₂ , (C ₈ H ₁₇ ) ₂ Sn (SCH ₂ CH ₂ COOC ₈ H ₁₇ ) ₂ , Mercaptide-type or sulfide-type organotin compounds such as (C ₈ H ₁₇ ) ₂ Sn (SCH ₂ COOC ₁₂ H ₂₅ ) ₂ , or organic compounds such as (C ₄ H ₉ ) ₂ SnO, (C ₈ H ₁₇ ) ₂ SnO Tin oxide and ethyl silicate dimethyl maleate, diethyl maleate And organic tin compounds such as reaction products with ester compounds such as dioctyl phthalate.

(C5) Metal salts As the metal salts, alkali metal salts of organic acids (for example, sodium naphthenate, potassium naphthenate, sodium octoate, sodium 2-ethylhexanoate, potassium laurate, etc.) are preferably used.

  The catalyst compound for the sol-gel reaction is preferably 0.01 to 50% by mass and more preferably 0.1 to 50% by mass with respect to the silane coupling agent of the present invention which is a raw material of the sol liquid. Preferably, it is 0.5 to 10% by mass.

  The solvent used for the sol-gel reaction is a solution that can be applied to various coating methods at the same time that the components in the sol solution are uniformly mixed to adjust the solid content, and the dispersion stability and storage stability of the composition are improved. It is to improve. The solvent to be used is not particularly limited as long as this purpose can be achieved. Preferable examples of these solvents include water, alcohols, aromatic hydrocarbons, ethers, ketones and esters.

  Examples of alcohols include monohydric alcohols and dihydric alcohols. Among these, monohydric alcohols are preferably saturated aliphatic alcohols having 1 to 8 carbon atoms. Specific examples of these alcohols include methanol, ethanol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, ethylene glycol. Examples thereof include monobutyl ether and ethylene glycol monoethyl ether acetate.

  Specific examples of aromatic hydrocarbons include benzene, toluene, xylene and the like. Specific examples of ethers include tetrahydrofuran and dioxane. Specific examples of ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, Specific examples of esters such as diisobutyl ketone include ethyl acetate, propyl acetate, butyl acetate, and propylene carbonate. These organic solvents can be used alone or in combination of two or more. The ratio of the organic solvent in the composition is not particularly limited, and an amount for adjusting the total solid content concentration according to the purpose of use is used.

A metal complex compound may be mixed in the sol solution. It is also preferable to use a compound having chelate coordination ability from the viewpoint of adjusting the curing reaction rate and improving the liquid stability. Preferably used are β-diketones and / or β-ketoesters.
Specific examples of the β-diketone and / or β-ketoester include acetylacetone, methyl acetoacetate, ethyl acetoacetate, acetoacetate-n-propyl, acetoacetate-i-propyl, acetoacetate-n-butyl, acetoacetate Acetic acid-sec-butyl, acetoacetic acid-t-butyl, 2,4-hexane-dione, 2,4-heptane-dione, 3,5-heptane-dione, 2,4-octane-dione, 2,4-nonane -Dione, 5-methyl-hexane-dione and the like can be mentioned. Of these, ethyl acetoacetate and acetylacetone are preferred, and acetylacetone is particularly preferred. These β-diketones and / or β-ketoesters may be used alone or in combination of two or more. Such β-diketones and / or β-ketoesters are 2 moles or more, preferably 3 to 20 moles per mole of the metal chelate compound, and if less than 2 moles, the storage stability of the resulting composition is poor. Become.

  Water is added to the sol solution for hydrolysis / condensation reaction of each component. The usage-amount of water is 1.2-3.0 mol normally with respect to 1 mol of each component, Preferably it is a 1.3-2.0 mol grade. The sol solution preferably has a total solid content concentration of 0.1 to 50% by mass, more preferably 1 to 40% by mass. When it exceeds 50 mass%, the storage stability of the composition is deteriorated, which is not preferable.

  In addition, the sol solution is applied to the surface of the substrate, and the sol-gel reaction is allowed to proceed on the substrate, whereby a film made of an inorganic oxide to which an organic group is bonded can be formed on the substrate surface.

  Next, the substrate to which the silane coupling agent is covalently bonded will be described. There are no particular restrictions on the material of the substrate, polyester, polyimide, polymethyl methacrylate, polystyrene, polypropylene, polyethylene, polyamide, nylon, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyether sulfone, silicone resin, polyacetal resin, fluorine A film made of a polymer such as a resin, a cellulose derivative, or a polyolefin, and an inorganic substrate such as a plate substrate, a glass substrate, a metal substrate, or a ceramic substrate are preferably used. When used as a substrate (for example, an electrode substrate) of a transmissive optical element, it is preferable to use a substrate member having a light transmittance of at least 50%. A substrate made of an inorganic material is preferable, and a glass substrate is more preferable. Moreover, even if the substrate is made of an organic material such as a polymer, if the layer made of an inorganic material is formed on the surface of the substrate, the silane coupling agent can be covalently bonded to the surface of the layer. Therefore, it is preferable. The layer made of an inorganic material differs depending on the use of the substrate. For example, when used as a substrate of a liquid crystal display element, an electrode layer made of a metal or a metal oxide can be mentioned.

  When used as a transmissive optical element, the electrode layer is also preferably made of a material having a high transmittance, and a transparent electrode having a light transmittance of at least 50% or more is preferably used. For example, a metal oxide layer represented by tin oxide-indium oxide (ITO), tin oxide, zinc oxide and the like is preferable. In the case of a reflective optical element application, as an electrode layer provided on an electrode substrate far from the viewing direction, metal oxides typified by tin oxide-indium oxide (ITO), tin oxide, zinc oxide, etc. In addition to the physical layer, a conductive polymer or a metal layer typified by carbon, copper, aluminum, gold, silver, nickel, platinum, or the like can be used.

  The liquid crystal element of the present invention includes a substrate on which the silane coupling agent represented by the general formula (1) is fixed by a covalent bond, and a liquid crystal layer supported by the substrate. When the liquid crystal layer is sandwiched between a pair of substrates, at least one of the pair of substrates may be the substrate of the present invention, that is, the substrate on which the silane coupling agent is fixed by a covalent bond. The other substrate is not particularly limited, and may be, for example, a substrate having an alignment film that is rubbed on the opposite surface, or a substrate in which the silane coupling agent is fixed by a covalent bond. . In the substrate of the present invention, the surface modified with the silane coupling agent is disposed as an opposing surface, that is, a surface in contact with the liquid crystal layer. In the present invention, by using the substrate whose surface is modified with the silane coupling agent, the alignment of the liquid crystal controlled by ON / OFF of the electric field or the height thereof can be controlled with higher accuracy. As a result, the liquid crystal element of the present invention has improved display characteristics.

  The method of the liquid crystal element of the present invention is not particularly limited, and any method such as STN method, TN method, MVA method, OCB method, etc. may be used, but the guest host method is preferable. A guest-host type liquid crystal device is a liquid crystal composition in which a dichroic dye is dissolved in a liquid crystal, which is enclosed in a cell, and an electric field is applied to the cell. The display is performed by changing the light absorption state of the cell.

  The dichroic dye that can be used in the present invention (hereinafter sometimes referred to as the dye of the present invention) may be any of the absorption maximum and the absorption band, but the yellow region (Y), magenta It is preferable to have an absorption maximum in the region (M) or the cyan region (C). A method for performing full color display by mixing a yellow dye, a magenta dye and a cyan dye is detailed in “Color Chemistry” (written by Sumio Tokita, Maruzen, 1982). Here, the yellow region is a range of 430 to 490 nm, the magenta region is a range of 500 to 580 nm, and the cyan region is a range of 600 to 700 nm. In the embodiment of the liquid crystal element for monochrome display, a black dichroic dye can be used. In addition, a plurality of pigments are mixed and used (for example, a pigment having an absorption maximum in the yellow region (Y), magenta region (M), or cyan region (C)), and a desired hue (for example, black) ) Can be adjusted.

The chromophore of the dichroic dye may be any, for example, azo dye, anthraquinone dye, perylene dye, merocyanine dye, azomethine dye, phthaloperylene dye, indigo dye, azulene dye, dioxazine dye, polythiophene dye, Examples include phenoxazone dyes (phenoxazin-3-one), and specific examples include those described in “Dicroic Dies for Liquid Crystal Display” (A. I. Vashchenko, CRC, 1994). It is done.
Preferred are azo dyes, anthraquinone dyes, perylene dyes, and phenoxazone dyes, and particularly preferred are anthraquinone dyes and phenoxazone dyes.

  The azo dye may be any of a monoazo dye, a bisazo dye, a trisazo dye, a tetrakisazo dye, a pentakisazo dye, and is preferably a monoazo dye, a bisazo dye, or a trisazo dye. The ring structure contained in the azo dye includes aromatic groups (benzene ring, naphthalene ring, etc.) as well as heterocyclic rings (quinoline ring, pyridine ring, thiazole ring, benzothiazole ring, oxazole ring, benzoxazole ring, imidazole ring, Benzimidazole ring, pyrimidine ring, etc.).

  As the substituent of the anthraquinone dye, those containing an oxygen atom, a sulfur atom or a nitrogen atom are preferable, and examples thereof include an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkylamino group and an arylamino group. The substitution number of the substituent may be any number, but di-substitution, tri-substitution, and tetrakis substitution are preferred, and di-substitution and tri-substitution are particularly preferred. The substitution position of the substituent may be any place, but preferably 1,4-position disubstitution, 1,5-position disubstitution, 1,4,5-position trisubstitution, 1,2,4-position trisubstitution, They are 1,2,5-trisubstituted, 1,2,4,5-tetrasubstituted, 1,2,5,6-tetrasubstituted structures.

  The substituent of the phenoxazone dye (phenoxazin-3-one) preferably includes an oxygen atom, a sulfur atom or a nitrogen atom, and examples thereof include an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkylamino group and an arylamino group.

  The host liquid crystal that can be used in the present invention is not particularly limited as long as it can coexist with the dichroic dye used in combination. For example, a liquid crystal compound exhibiting a nematic phase or a smectic phase can be used. Specific examples thereof include azomethine compounds, cyanobiphenyl compounds, cyanophenyl esters, fluorine-substituted phenyl esters, cyclohexanecarboxylic acid phenyl esters, fluorine-substituted cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexane, fluorine-substituted phenylcyclohexanes, cyano-substituted phenylpyrimidines, Fluorine-substituted phenylpyrimidine, alkoxy-substituted phenylpyrimidine, fluorine-substituted alkoxy-substituted phenylpyrimidine, phenyldioxane, tolan compounds, fluorine-substituted tolan compounds, alkenylcyclohexylbenzonitrile and the like. The liquid crystal compounds described in pages 154 to 192 and pages 715 to 722 of “Liquid Crystal Device Handbook” (Japan Society for the Promotion of Science 142nd edition, Nikkan Kogyo Shimbun, 1989) can be used. It is also possible to use a fluorine-substituted host liquid crystal suitable for TFT driving. For example, Merck's liquid crystal (ZLI-4692, MLC-6267, 6284, 6287, 6288, 6406, 6422, 6423, 6425, 6435, 6437, 7700, 7800, 9000, 9100, 9200, 9300, 10,000, etc.) Liquid crystal (LIXON 5036xx, 5037xx, 5039xx, 5040xx, 5041xx, etc.).

  The dielectric anisotropy of the host liquid crystal used in the present invention may be positive or negative. When the host liquid crystal having positive dielectric anisotropy is horizontally aligned, the liquid crystal is horizontally aligned when no voltage is applied, so that the dichroic dye also becomes horizontal and absorbs light. On the other hand, since the liquid crystal molecules are tilted vertically when a voltage is applied, the dichroic dye is also tilted vertically, so that light is transmitted. That is, the mode is such that white display is performed when a voltage is applied, and black display is performed when no voltage is applied. When the host liquid crystal having a negative dielectric anisotropy is vertically aligned, when no voltage is applied, the liquid crystal is vertically aligned, so that the dichroic dye is also vertical and transmits without absorbing light. On the other hand, since the liquid crystal molecules are tilted horizontally when a voltage is applied, the dichroic dye is also tilted horizontally, and as a result, absorbs light. That is, the mode is such that white display is performed when no voltage is applied, and black display is performed when a voltage is applied. In the present invention, it is more preferable to use a host liquid crystal having a positive dielectric anisotropy.

  In the present invention, for the purpose of changing the physical properties of the host liquid crystal to a desired range (for example, for the purpose of setting the temperature range of the liquid crystal phase to a desired range), the liquid crystal layer does not exhibit liquid crystallinity. A compound may be added. Moreover, you may contain compounds, such as a chiral compound, a ultraviolet absorber, and antioxidant. Examples of such additives include chiral agents for TN and STN described in pages 199 to 202 of “Liquid Crystal Device Handbook” (edited by the Japan Society for the Promotion of Science 142nd Committee, Nikkan Kogyo Shimbun, 1989). It is done.

  Although there is no restriction | limiting in particular about content of a host liquid crystal and a dichroic dye in the liquid crystal element of this invention, Content of a dichroic dye is 0.1-15 mass% with respect to content of a host liquid crystal. It is preferably 0.5 to 6% by mass. In addition, the content of the host liquid crystal and the dichroic dye is adjusted to a microcapsule containing both, and the absorption spectrum of the liquid crystal cell enclosing the microcapsule is measured to show the desired optical density as the liquid crystal cell. It is desirable to determine the dye concentration required for

  A schematic cross-sectional view of one embodiment of the liquid crystal element of the present invention is shown in FIG. In FIG. 1, the size, number and position of each element shown are relative and not absolute. In the liquid crystal element 1, a pair of substrates 2 and 8 are disposed to face each other at an interval of 1 to 50 μm via a spacer or the like (not shown), and a liquid crystal layer 5 is provided between the pair of substrates 2 and 8. Transparent electrodes 3 and 7 are formed on the opposing surface of the substrate so that a voltage can be supplied. Layers 4 and 6 formed by connecting the silane coupling agent represented by the general formula (1) by a covalent bond are provided on the surfaces of the transparent electrodes 3 and 7. As the spacer, for example, those described in pages 257 to 262 of “Liquid Crystal Device Handbook” (edited by Japan Society for the Promotion of Science 142nd Committee, Nikkan Kogyo Shimbun, 1989) can be used.

  The liquid crystal element of the present invention can be driven by a simple matrix driving method or an active matrix driving method using a thin film transistor (TFT). The driving method is described in detail, for example, on pages 387 to 460 of “Liquid Crystal Device Handbook” (edited by the 142th Committee of the Japan Society for the Promotion of Science, Nikkan Kogyo Shimbun, 1989). Available as a method.

  The liquid crystal element of the present invention can be suitably used as various types of electro-optical devices such as display elements such as computers, watches, and calculators, electro-optical shutters, electro-optical apertures, optical communication optical path switching switches, and optical modulators.

  The present invention will be described more specifically with reference to the following examples. The materials, reagents, amounts and ratios, operations, etc. shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples. .

(Synthesis Example 1: Synthesis of Silane Coupling Agent No. 7)

(Step 1: Synthesis of Intermediate M-2)
(M-1) (manufactured by Tokyo Chemical Industry Co., Ltd.) Mater. Chem. 11, pp. 302-311, 2001, and intermediate M-2 was synthesized.
(Step 2: Synthesis of silane coupling agent No. 7 represented by the general formula (1))
Intermediate (M-2) (2.0 g) and aminopropanetrimethoxysilane (1.1 g) were stirred in 30 ml of methylene chloride at room temperature for 3 hours. Water was added, the organic layer was extracted with ethyl acetate, dried over magnesium sulfate, the organic solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography to obtain the compound of the present invention (No. 7) 2.6 g was obtained. NMR data is shown below.
H-NMR (CDCl ₃ ): 7.70 (2H, d), 7.5 (2H, d), 7.35 (2H, b), 6.94 (2H, b), 4.0 (2H, m), 3.40 (9H, s), 3.2 (2H, m), 1.8 (2H, m), 1.2-1.4 (8H, m), 0.6 (2H, m) ).

(Example 1: Production of liquid crystal element of the present invention)
A glass substrate (10 cm × 10 cm) (made by IGC) with a thin film of indium tin oxide (ITO) as a transparent electrode was immersed in 50 ml of a toluene solution of 50 mg of the silane coupling agent (No. 7) of the present invention. . One drop of acetic acid was added, and after 1 hour, the substrate was taken out and washed with acetonitrile. Then, the board | substrate of this invention was produced by heating a board | substrate at 120 degreeC for 10 minute (s).
Next, a polyimide horizontal alignment film “SE-130” manufactured by Nissan Chemical Industries was applied on a glass substrate, and then sintered at 180 ° C. After rubbing the substrate, as a counter substrate, the glass substrate with a transparent electrode surface-treated with the silane coupling agent (No. 7) of the present invention is faced, and an epoxy resin adhesive containing aluminum spheres having a diameter of 17 μm is used. The periphery was sealed with an agent to form a cell. Thereafter, between the pair of substrates, a cyano nematic liquid crystal 5CB having a positive dielectric anisotropy as a host liquid crystal (manufactured by Tokyo Chemical Industry Co., Ltd.) and a liquid containing the following dichroic dye at a ratio of 1 wt% are supplied into the cell liquid crystal. Injected from the inlet. The concentration of the dichroic dye in the obtained liquid crystal cell was measured with a polarized light of 450 nm (UV3100, visible absorption spectrometer manufactured by Shimadzu Corporation), and the absorption concentration ratio when no voltage was applied and when applied (AC 20 V, 60 Hz) ( = (Absorbance when voltage is applied) / (absorbance when no voltage is applied)). The obtained results are shown in Table 1.

(Comparative Example 1: Production of comparative liquid crystal element)
Next, a substrate was produced in the same manner as in Example 1 except that octadecyltrimethoxysilane (manufactured by Azmax Co.) was used instead of the silane coupling agent (No. 7). A liquid crystal device for a comparative example was produced in the same manner as in Example 1 except that this substrate was used, and the absorption concentration ratio was similarly measured. The obtained results are shown in Table 1.

(Example 2)
A liquid crystal device of the present invention was produced in the same manner as in Example 1 except that fluorine nematic liquid crystal ZLI-5081 (manufactured by Merck) having positive dielectric anisotropy was used as the host liquid crystal, and its absorption The concentration ratio was measured in the same manner. The obtained results are shown in Table 1.
(Comparative Example 2)
A liquid crystal element for a comparative example was produced in the same manner as in Comparative Example 1 except that a fluorine-based nematic liquid crystal ZLI-5081 (manufactured by Merck) having a positive dielectric anisotropy was used as the host liquid crystal. The absorption concentration ratio was measured. The obtained results are shown in Table 1.

  As is apparent from the results shown in Table 1, silane coupling agent No. The liquid crystal device of the present invention using the substrate surface-modified with 7 has a higher absorption concentration ratio than the liquid crystal device for the comparative example using the substrate surface-treated with the conventional silane coupling agent. I understand. As the host liquid crystal, a high absorption concentration ratio is given both in the case of cyano liquid crystal and fluorine liquid crystal.

  That is, according to the present invention, a liquid crystal display element with high display quality can be obtained by using a substrate treated with a specific silane coupling agent, and can be used effectively in various devices. For example, it is suitably used for display devices such as desk calculators, watches, table clocks, coefficient display boards, word processors, personal computers, liquid crystal televisions, etc., and its application range is wide.

It is a cross-sectional schematic diagram of one Embodiment of the liquid crystal display element of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display element 2 Board | substrate 3 Electrode layer 4 The layer in which the silane coupling agent was connected by the covalent bond 5 The liquid crystal layer 6 The layer in which the silane coupling agent was connected by the covalent bond 7 Electrode layer 8 Substrate

Claims (4)

A liquid crystal element having a substrate and a liquid crystal layer supported by the substrate, wherein the substrate is a substrate to which a silane coupling agent represented by the following general formula (1) is fixed by a covalent bond:

In the formula, each of X ¹ , X ² , X ³ and X ⁴ represents a hydrogen atom or a substituent, R ¹ represents a nitro group, a halogen atom, a cyano group, or a substituted or unsubstituted alkoxy group, and L ¹ represents A divalent linking group is represented, and Y ¹ , Y ² and Y ³ each represent a substituent, but at least one is a leaving group. ^2. The liquid crystal device according to claim 1, wherein, in the general formula (1), X ¹ , X ² , X ³ and X ⁴ are hydrogen atoms, and R ¹ is a cyano group. The liquid crystal element according to claim 1, which is a guest host type liquid crystal element. The liquid crystal element according to claim 1, wherein the substrate on which the silane coupling agent is fixed by a covalent bond is a transparent electrode substrate.

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