TWI515234B - Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Description

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

The present invention relates to a liquid crystal alignment agent containing a polyoxyalkylene obtained by polycondensation of an alkoxysilane, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film.

In recent years, among the display modes of liquid crystal display elements, vertical (VA) liquid crystal display elements have been widely used in large-screen liquid crystal televisions or high-definition portable applications (digital cameras or mobile phone display units). Used. As the VA method, a MVA method (Multi Vertical Alignment) in which a protrusion is formed on a TFT substrate or a color filter substrate in order to control the falling direction of the liquid crystal, and a slit formed by the ITO electrode formed on the substrate are known. The electric field controls the PVA (Paterned Vertical Alignment) mode of the liquid crystal falling direction.

As another VA alignment method, there is a PSA (Polymer sustained Alignment) method. Among the VA methods, the PSA method is a technology that has received attention in recent years. In this manner, a photopolymerizable compound is usually added to a liquid crystal, and after the liquid crystal panel is produced, an electric field is applied and the liquid crystal is irradiated with ultraviolet rays (UV). As a result, the polymerizable compound is immobilized in the alignment direction of the liquid crystal by photopolymerization, and pretilt is generated, and the response speed is improved. In the PSA method, a slit is formed on the one-side electrode constituting the liquid crystal panel, and even if the projection on the opposite side is not provided with the protrusion in the MVA mode or the slit structure in the PVA mode, the operation can be simplified, or the manufacturing is simplified or An advantage of excellent panel transmittance can be obtained (refer to Patent Document 1).

On the other hand, an inorganic liquid crystal alignment film material is known in addition to an organic liquid crystal alignment film material such as polyimide which has been conventionally used. For example, as a material of a coating-type inorganic alignment film, a composition containing a reaction product of tetraalkoxysilane, trialkoxide, alcohol, and oxalic acid is used, and it is reported that vertical alignment is formed on the electrode substrate of the liquid crystal display device. A liquid crystal alignment film excellent in heat resistance and uniformity (refer to Patent Document 2).

Further, by using a liquid crystal alignment agent composition containing a reaction product of a tetraalkanoxane, a specific trialkoxysilane and water, or a specific glycol ether solvent, it is reported that formation of a display preventing defect is caused, and even if A liquid crystal alignment film which does not cause image sticking after a long period of time, does not reduce the ability of liquid crystal alignment, and has a small reduction in voltage and heat retention (refer to Patent Document 3).

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] JP-A-2004-302061

[Patent Document 2] Japanese Patent Publication No. 09-281502

[Patent Document 3] JP-A-2005-250244

Conventionally, in the liquid crystal display device of the PSA type, the solubility of the polymerizable compound added to the liquid crystal is low, and when the amount of addition is increased, there is a problem that precipitation occurs at a low temperature. Further, when the amount of the polymerizable compound added is reduced, a good alignment state cannot be obtained. In addition, since the unreacted polymerizable compound remaining in the liquid crystal becomes an impurity (contamination) in the liquid crystal, there is a problem that the reliability of the liquid crystal display element is lowered.

In the PSA method, even when the amount of the polymerizable compound added to the liquid crystal is small, even when the polymerizable compound is not added, the response speed is improved and the alignment state is good. A liquid crystal alignment agent for a liquid crystal display element for a liquid crystal display element, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film.

The following is the gist of the present invention.

[1] A liquid crystal alignment agent for a device, comprising: a polyoxyalkylene obtained by polycondensing an alkoxysilane containing an alkoxysilane represented by the formula (1) and an alkoxysilane represented by the formula (2);

R ¹ Si(OR ² ) ₃ (1)

(R ¹ is a hydrocarbon group having 8 to 30 carbon atoms which may be substituted by a fluorine atom, and R ² is an alkyl group having 1 to 5 carbon atoms),

[Chemical 1]

R ³ is a hydrocarbon group having 1 to 18 carbon atoms, and R ⁴ is an alkyl group having 1 to 5 carbon atoms.

[2] The liquid crystal alignment agent according to [1] above, wherein R ³ of the above formula (2) is an alkylene group.

[3] The liquid crystal alignment agent according to the above [1], wherein R ³ of the above formula (2) is represented by the following formula (3) (except that m and n are each an integer of 0 to 6).

[Chemical 2]

[4] The liquid crystal alignment agent according to any one of the above [1], wherein the polyoxyalkylene is further obtained by polycondensation of an alkoxysilane containing an alkoxysilane represented by the following formula (4). Polyoxane,

(R ⁵ ) _n Si(OR ⁶ ) _4-n (4)

(R ⁵ is a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a hetero atom, a halogen atom, an amine group, a glycidoxy group, a decyl group, an isocyanate group or a urea group, and R ⁶ is a carbon atom. An alkyl group of 1 to 5, and n is an integer of 0 to 3).

[5] The liquid crystal alignment agent according to the above [4], wherein n of the formula (4) is 0, and the alkoxydecane-based tetraalkoxysilane represented by the above formula (4).

[6] The liquid crystal alignment agent according to any one of the above [1] to [5] wherein the polyoxyalkylene oxide contains alkoxy oxane of the formula (1) in the peralkyl alkane 0.1 to 30. Mol %, and obtained by polycondensation of alkoxy oxane containing 3 to 70 mol% of alkoxy oxane represented by formula (2) in peroxane.

[7] The liquid crystal alignment agent according to any one of the above [4], wherein the polyoxyalkylene oxide contains alkoxysilane of the formula (4) in the total alkoxysilane of 10 to 96.9. It is obtained by polycondensation of a mole of alkoxypropane.

[8] The liquid crystal alignment agent according to any one of the above [1], wherein the content of the polysiloxane is 0.5 to 15% by mass in terms of SiO ₂ conversion.

[9] A liquid crystal alignment film obtained by applying the liquid crystal alignment agent according to any one of the above [1] to [8] on a substrate, drying, and calcining.

[10] A liquid crystal display element comprising the liquid crystal alignment film of [9] above.

[11] A liquid crystal display element which is obtained by coating a liquid crystal alignment agent according to any one of [1] to [8], and for holding a liquid crystal cell of liquid crystal using two substrates which have been calcined, The state of the voltage illuminates the UV.

[12] A method of producing a liquid crystal display device, which comprises applying the liquid crystal alignment agent according to any one of [1] to [8] above, and using the two substrates that have been calcined to hold the liquid crystal, and applying a voltage. The state is irradiated with UV.

According to the liquid crystal alignment agent of the present invention, in the PSA method, even when the amount of the polymerizable compound added to the liquid crystal is small, or even when a liquid crystal to which no polymerizable compound is added is used, the response speed is improved and A liquid crystal alignment film for a liquid crystal display element for a liquid crystal display element in a good alignment state, and a display element having the liquid crystal alignment film.

[Best form of implementing the invention]

The invention is described in detail below.

[polyoxyalkylene]

The present invention is a PSA-based liquid crystal alignment agent containing a polyoxyalkylene obtained by polycondensation of an alkoxysilane having an alkoxydecane represented by the formula (1) and an alkoxysilane represented by the formula (2).

R ¹ Si(OR ² ) ₃ (1)

R ¹ is a hydrocarbon group having 8 to 30 carbon atoms which may be substituted by a fluorine atom, and R ² is an alkyl group having 1 to 5 carbon atoms. Further, in the present specification, the term "substitutable" means "substituted or unsubstituted".

[Chemical 3]

R ³ is a hydrocarbon group having 1 to 18 carbon atoms, and R ⁴ is an alkyl group having 1 to 5 carbon atoms.

R ¹ (hereinafter also referred to as a specific organic group) of the alkoxydecane represented by the formula (1) is a hydrocarbon group having 8 to 30, preferably 8 to 22 carbon atoms which may be substituted by fluorine, as long as it has a liquid crystal The effect of the vertical alignment can be achieved without particular limitation. As such an example, an alkyl group, a fluoroalkyl group, an alkenyl group, a phenethyl group, a styrylalkyl group, a naphthyl group, a fluorophenylalkyl group, etc. are mentioned. Among these, alkoxysilane having R ¹ as an alkyl group or a fluoroalkyl group is preferable because it is easily obtained from a commercially available product at a relatively inexpensive price. In particular, it is preferred that R ¹ is an alkyl alkoxysilane. The polyoxyalkylene used in the present invention may have a plurality of such specific organic groups.

R ^{2 of the} alkoxysilane represented by the formula (1) is an alkyl group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms. More preferably, R ² is a methyl group or an ethyl group.

Specific examples of the alkoxydecane represented by the formula (1) are exemplified, but are not limited thereto.

For example, octyltrimethoxydecane, octyltriethoxydecane, decyltrimethoxydecane, decyltriethoxydecane, dodecyltrimethoxydecane, dodecyltriethyl Oxydecane, cetyltrimethoxydecane, cetyltriethoxydecane, heptadecyltrimethoxydecane, heptadecyltriethoxydecane,octadecyltrimethoxydecane , octadecyltriethoxydecane, nonadecyltrimethoxynonane, nonadecyltriethoxydecane, undecyltriethoxydecane,undecyltrimethoxydecane,21 -dodecadienyltriethoxydecane,tridecafluorooctyltrimethoxydecane,tridecafluorooctyltriethoxydecane,heptadecafluorodecyltrimethoxydecane,heptadecafluorodecyltriethyl Oxydecane, isooctyltriethoxydecane, phenethyltriethoxydecane, pentafluorophenylpropyltrimethoxydecane, m-styrylethyltrimethoxydecane, p-styryl Ethyltrimethoxydecane, (1-naphthyl)triethoxydecane, (1-naphthyl)trimethoxydecane, and the like. Among them, preferred are octyltrimethoxydecane, octyltriethoxydecane, decyltrimethoxydecane, decyltriethoxydecane,dodecyltrimethoxydecane,dodecyltrifoxide Ethoxydecane, cetyltrimethoxydecane, cetyltriethoxydecane, heptadecyltrimethoxydecane, heptadecyltriethoxydecane,octadecyltrimethoxy Decane, octadecyltriethoxydecane, nonadecyltrimethoxynonane, nonadecyltriethoxydecane, undecyltriethoxydecane, or undecyltrimethoxydecane .

In the allyl alkane used for obtaining a polyoxyalkylene, the alkoxydecane represented by the formula (1) having the specific organic group described above is preferably 0.1 mol% or more in order to obtain good liquid crystal alignment. . More preferably, it is 0.5 mol%. More preferably, it is 1% by mole. Moreover, in order to obtain sufficient hardening characteristics of the liquid crystal alignment film to be formed, it is preferably 30 mol% or less. More preferably, it is 22 mol% or less.

R ³ (hereinafter also referred to as a second specific organic group) of the alkoxydecane represented by the formula (2) is a hydrocarbon group having 1 to 18 carbon atoms, preferably 1 to 12 carbon atoms, and an aliphatic hydrocarbon; for example, an aliphatic ring, A ring structure of an aromatic ring and a hetero ring; and a hetero atom such as an oxygen atom, a nitrogen atom or a sulfur atom. It is preferably an alkyl group or a phenyl group. The alkyl group has 1 to 18 carbon atoms, more preferably 1 to 12 carbon atoms. The phenylene group is represented by the following formula (3), and m and n are each an integer of 0 to 6, and preferably an integer of 0 to 2.

[Chemical 4]

R ^{4 of the} alkoxydecane represented by the formula (2) is the same as defined by R ² of the above formula (1); further, a preferred group of R ⁴ is also the same as in the case of R ² .

Specific examples of the alkoxysilane represented by the formula (2) are not limited thereto. For example, allyl trimethoxy decane, allyl triethoxy decane, butenyl trimethoxy decane, butenyl triethoxy decane, pentenyl trimethoxy decane, pentenyl group can be mentioned. Triethoxy decane, hexynyl trimethoxy decane, hexynyl triethoxy decane, heptenyl trimethoxy decane, heptenyl triethoxy decane, octenyl trimethoxy decane, octene Triethoxy decane, undecynyl trimethoxy decane, undecynyl triethoxy decane, allyloxy undecyl trimethoxy decane, allyloxy undecyl triethoxy Basear, vinyl phenyl trimethoxy decane, vinyl phenyl triethoxy decane, vinyl phenyl ethyl trimethoxy decane, vinyl phenyl ethyl triethoxy decane, and the like.

In the PSA method, when the amount of the polymerizable compound to be added to the liquid crystal is small, and even when a liquid crystal to which the polymerizable compound is not added is used, the second specific organic group is provided in order to increase the response speed of the liquid crystal display element. The alkoxysilane represented by the formula (2) is preferably 3 mol% or more in the peralkyl alkane to obtain a polyoxyalkylene. More preferably, it is more than 5 mol%. More preferably, it is 10 mol% or more. Further, in order to sufficiently cure the formed liquid crystal alignment film, it is preferably 70 mol% or less.

In the present invention, the alkoxydecane represented by the formula (1) preferably contains 0.1 to 30 mol%, particularly preferably 2 to 20 mol%, and the formula (2) in the peralkyl alkane to be used. The alkoxydecane shown is preferably from 3 to 70 mol%, particularly preferably from 5 to 30 mol%, based on the total alkoxysilane used.

In the present invention, in addition to the alkoxydecane represented by the formula (1) and the formula (2), an alkoxysilane represented by the following formula (4) may be used. Since the alkoxysilane represented by the formula (4) imparts various properties to the polyoxyalkylene, one or a plurality of kinds can be used depending on the necessary characteristics.

(R ⁵ ) _n Si(OR ⁶ ) _4-n (4)

R ⁵ is a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a hetero atom, a halogen atom, an amine group, a glycidoxy group, a decyl group, an isocyanate group or a urea group. R ⁶ is an alkyl group having 1 to 5 carbon atoms, preferably an alkyl group having 1 to 3; and n is an integer of 0 to 3, preferably 0 to 2.

R ^{5 of the} alkoxydecane represented by the formula (4) is a hydrogen atom or an organic group having 1 to 6 carbon atoms (hereinafter also referred to as a third organic group). Examples of the third organic group include an aliphatic hydrocarbon; a ring structure such as an aliphatic ring, an aromatic ring, or a heterocyclic ring; an unsaturated bond; and a hetero atom such as an oxygen atom, a nitrogen atom, or a sulfur atom; An organic group having a branched structure and having 1 to 6 carbon atoms. This organic group may be substituted by a halogen atom, an amine group, a glycidoxy group, a decyl group, an isocyanate group, a urea group or the like.

Specific examples of the alkoxysilane represented by the formula (4) are not limited thereto.

In the alkoxy decane of the formula (4), specific examples of the alkoxy decane when R ⁵ is a hydrogen atom include, for example, trimethoxy decane, triethoxy decane, tripropoxy decane, and tributyloxy. Base decane and the like.

Further, in the alkoxysilane of the formula (4), specific examples of the alkoxysilane when R ⁵ is the third organic group include, for example, methyltrimethoxydecane, methyltriethoxydecane, and B. Trimethoxy decane, ethyl triethoxy decane, propyl trimethoxy decane, propyl triethoxy decane, methyl tripropoxy decane, 3-aminopropyl trimethoxy decane, 3- Aminopropyl triethoxy decane, N-2 (aminoethyl) 3-aminopropyl triethoxy decane, N-2 (aminoethyl) 3-aminopropyl trimethoxy decane , 3-(2-Aminoethylaminopropyl)trimethoxynonane, 3-(2-aminoethylaminopropyl)triethoxydecane, 2-aminoethylaminomethyl Trimethoxydecane, 2-(2-aminoethylthioethyl)triethoxydecane, 3-mercaptopropyltriethoxydecane, mercaptomethyltrimethoxydecane, vinyltriethoxy Decane, 3-isocyanate propyl triethoxy decane, trifluoropropyl trimethoxy decane, chloropropyl triethoxy decane, bromopropyl triethoxy decane, 3-mercaptopropyl trimethoxy decane, Dimethyldiethoxydecane, dimethyldimethoxydecane Diethyldiethoxydecane, diethyldimethoxydecane, diphenyldimethoxydecane, diphenyldiethoxydecane, 3-aminopropylmethyldiethoxydecane, 3-aminopropyl dimethyl ethoxy decane, trimethyl ethoxy decane, trimethyl methoxy decane, γ-ureidopropyl triethoxy decane, γ-ureidopropyl trimethoxy Alkane and γ-ureidopropyltripropoxydecane.

The polyoxyalkylene used in the present invention may have one or more of the above-mentioned types for the purpose of improving the adhesion to the substrate, the affinity with the liquid crystal molecules, and the like without damaging the effects of the present invention. An alkoxydecane represented by the formula (4).

In the alkoxydecane represented by the formula (4), the alkoxy decane wherein n is 0 is a tetraalkyloxane. Since the tetraalkane is easily condensed with the alkoxysilane represented by the formula (1) and the formula (2), it is preferably used for obtaining the polyoxyalkylene of the present invention.

Thus, as the alkoxy decane wherein n is 0 in the formula (4), more preferably tetramethoxy decane, tetraethoxy decane, tetrapropoxy decane or tetrabutoxy decane, particularly tetramethoxy Preferably, decane or tetraethoxydecane is used.

When the alkoxysilane of the formula (4) is used in combination, the alkoxydecane used in the formula (4) is preferably used in an amount of from 10 to 96.9 mol% in the peralkyl alkane for obtaining a polyoxyalkylene. . More preferably, it is 35 to 99.8 mol%.

[Manufacturing method of polyoxyalkylene]

The method of obtaining the polyoxyalkylene used in the present invention is not particularly limited. In the present invention, the alkoxy decane of the above formula (1) and formula (2), which are essential components, is obtained by condensation in an organic solvent. Usually, polyoxyalkylene is obtained by condensing and polymerizing such alkoxysilane as a solution uniformly dissolved in an organic solvent.

In the method of polycondensation of a polyoxyalkylene oxide, for example, a method of hydrolyzing and condensing an alkoxysilane in a solvent such as an alcohol or a diol can be mentioned. At this time, the hydrolysis ‧ condensation reaction may be either partial hydrolysis or complete hydrolysis. In the case of complete hydrolysis, it is theoretically preferable to add 0.5 times mole of water of the total alkoxy group in the alkoxysilane, but it is usually preferred to add water in an excess of 0.5 times mole.

In the present invention, the amount of water used in the above reaction can be appropriately selected as desired, but it is usually 0.5 to 2.5 times moles of the total alkoxy group in the alkoxysilane.

Further, in general, an acid such as hydrochloric acid, sulfuric acid, nitric acid, acetic acid, formic acid, oxalic acid, maleic acid or fumaric acid may be used for the purpose of promoting hydrolysis and condensation reaction; ammonia, methylamine, ethylamine, ethanolamine, and the like. a base such as ethylamine; a metal salt such as hydrochloric acid, sulfuric acid or nitric acid; or a catalyst. Further, by heating the alkoxysilane as a dissolved solution, the hydrolysis and condensation reaction are further promoted, which is also a general matter. At this time, the heating temperature and the heating time can be appropriately selected as desired. For example, a method of heating at 50 ° C for 24 hours, stirring, and heating under reflux for 1 hour, stirring, and the like can be mentioned.

Further, as another method, for example, a method in which a mixture of alkoxysilane, a solvent, and oxalic acid is heated and condensed and polymerized is mentioned. Specifically, a method in which oxalic acid is added to an alcohol in advance, and after preparing an oxalic acid alcohol solution, the solution is heated and mixed with alkoxysilane. In this case, the amount of oxalic acid to be used is preferably set to 0.2 to 2 mol based on 1 mol of the total alkoxy group of the alkoxydecane. The heating of this method can be carried out at a liquid temperature of 50 to 180 °C. It is preferably a method of heating under reflux for several tens of minutes to ten hours without causing evaporation, volatilization or the like of the liquid.

In the case of obtaining a polyoxyalkylene oxide, if a plurality of alkoxysilanes are used, a mixture of alkoxysilanes which have been previously mixed or a plurality of alkoxysilanes may be sequentially mixed.

The solvent (hereinafter also referred to as a polymerization solvent) used in the polycondensation of the alkoxysilane is not particularly limited as long as it can dissolve the alkoxysilane. Further, even if the alkoxysilane is not dissolved, it may be dissolved as long as the polyalkylene oxide is subjected to a polycondensation reaction. In general, since alcohol is formed by the polycondensation reaction of alkoxysilane, an alcohol, a glycol, a glycol ether, or an organic solvent having good compatibility with an alcohol can be used.

Specific examples of such a polymerization solvent include alcohols such as methanol, ethanol, propanol, butanol, and diacetone alcohol: ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, and hexanediol. , 3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,3-pentane Glycols such as diol, 1,4-pentanediol, 1,5-pentanediol, 2,4-pentanediol, 2,3-pentanediol, 1,6-hexanediol, etc. Alcohol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol Propyl ether, ethylene glycol dibutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethyl Glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl Ether, propylene glycol monobutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, propylene glycol dibutyl ether, etc. Ethers, N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, γ-butyrolactone, dimethyl hydrazine, tetramethyl Based on urea, hexamethylphosphoric acid triamide, m-cresol and the like.

In the present invention, the above-mentioned polymerization solvent may be used in combination of plural kinds.

The polymerization solution of the polyoxyalkylene obtained by the above method (hereinafter also referred to as a polymerization solution) is a arsenic atom of a peralkyl alkane which is charged as a raw material, and is converted into a SiO ₂ concentration (hereinafter also referred to as The concentration in terms of SiO ₂ is preferably 20% by mass or less, and more preferably 5 to 15% by mass. A homogeneous solution can be obtained by selecting any concentration within this concentration range to inhibit gel formation.

[Polyoxane solution]

In the present invention, the polymerization solution obtained by the above method can be prepared as a solution of polyoxyalkylene as it is, and the solution obtained by the above method can be diluted or added with a solvent to be diluted or other as needed. The solvent is replaced to prepare a solution of polyoxyalkylene.

In this case, the solvent to be used (hereinafter also referred to as an additive solvent) may be the same as the polymerization solvent or may be another solvent. The solvent to be added is not particularly limited as long as it can be uniformly dissolved in the polyoxyalkylene, and one type or plural types can be used arbitrarily.

Specific examples of the solvent to be added in this manner include, in addition to the solvent exemplified in the above-mentioned polymerization solvent, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; methyl acetate; An ester of ethyl acetate or ethyl lactate.

These solvents can improve the coating property when the viscosity of the liquid crystal alignment agent is adjusted or when the liquid crystal alignment agent is coated on the substrate by spin coating, offset printing, inkjet or the like.

[Other ingredients]

In the present invention, other components other than polysiloxane, such as inorganic microparticles, metalloxan oligomers, metalloxane polymers, leveling agents, and the like, do not impair the effects of the present invention. It may also contain a component such as a surfactant.

As the inorganic fine particles, fine particles such as cerium oxide fine particles, alumina fine particles, titania fine particles, or magnesium fluoride fine particles are preferable, and those in a colloidal solution state are preferable. The colloidal solution may be one in which the inorganic fine particles are dispersed in a dispersion medium, or may be a colloidal solution of a commercially available product. In the present invention, by including inorganic fine particles, the surface shape of the formed cured film can be changed or other functions can be imparted. The inorganic particles have an average particle diameter of preferably 0.001 to 0.2 μm, more preferably 0.001 to 0.1 μm. When the average particle diameter of the inorganic fine particles exceeds 0.2 μm, the cured film formed by using the prepared coating liquid may be used, and the transparency may be lowered.

Examples of the dispersion medium of the inorganic fine particles include water and an organic solvent. As the colloidal solution, the pH or pKa is preferably adjusted to 1 to 10 from the viewpoint of the stability of the coating liquid for film formation. More preferably 2 to 7.

Examples of the organic solvent used as the dispersion medium of the colloidal solution include methanol, propanol, butanol, ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, diethylene glycol, dipropylene glycol, and B. Alcohols such as diol monopropyl ether; ketones such as methyl ethyl ketone and methyl isobutyl ketone; aromatic hydrocarbons such as toluene and xylene; dimethylformamide and dimethyl An amide such as guanamine or N-methylpyrrolidone; an ester such as ethyl acetate, butyl acetate or γ-butyrolactone; or an ether such as tetrahydrofuran or 1,4-dioxane. Among these, alcohols or ketones are preferred. These organic solvents can be used singly or in combination of two or more kinds as a dispersion medium.

As the metal oxyalkylene oligomer or the metal oxyalkylene polymer, a single or composite oxide precursor of ruthenium, titanium, aluminum, ruthenium, osmium, iridium, tin, indium, zinc or the like can be used. The metal oxyalkylene oligomer or the metal oxyalkylene polymer may be a commercially available product, or may be a monomer such as a metal alkoxide, a nitrate, a hydrochloride or a carboxylate, by hydrolysis or the like. The law is obtained.

Specific examples of the metal oxyalkylene oligomer and the metal oxyalkylene polymer which are commercially available products include methyl silicate 51, methyl silicate 53A, ethyl silicate 40, ethyl silicate 48, EMS-485, SS- manufactured by colcoat. A Titanoxane oligomer such as a siloxane oxide oligomer or a siloxane polymer such as 101 or a titanium-n-butoxytetrapolymer manufactured by Kanto Chemical Co., Ltd. These can be used individually or in mixture of 2 or more types.

Further, a leveling agent, a surfactant, and the like can be used, and a commercially available product is particularly preferable because it is easy to obtain.

Further, the method of mixing the above other components to the polyoxyalkylene may be carried out simultaneously with the polyoxyalkylene, and may not be particularly limited thereafter.

[Liquid alignment agent]

The liquid crystal alignment agent of the present invention is a solution containing the above polyoxyalkylene oxide and other components as required. In this case, as the solvent, a solvent selected from the group consisting of the polymerization solvent of the above polyoxyalkylene and the added solvent can be used. The content of the polysiloxane of the liquid crystal alignment agent is preferably from 0.5 to 15% by mass, and more preferably from 1 to 6% by mass, in terms of SiO ₂ . When it is in the range of such SiO ₂ conversion concentration, it is easy to obtain a desired film thickness by one application, and it is easy to obtain a sufficient pot life.

The method of preparing the liquid crystal alignment agent of the present invention is not particularly limited. The polyoxyalkylene used in the present invention may be in a state of being uniformly mixed as needed. Usually, the polyoxyalkylene is condensed and polymerized in a solvent, so that the solution of the polyoxyalkylene is used as it is, or it is convenient to add other components as needed in the solution of polyoxyalkylene. Further, the most convenient method is to use a polymerization solution of polyoxyalkylene as it is.

Further, when the content of the polyoxyalkylene in the liquid crystal alignment agent is adjusted, a solvent selected from the group consisting of the polymerization solvent of the polyoxyalkylene and the added solvent can be used.

[Liquid alignment film]

The liquid crystal alignment film of the present invention is obtained by using the liquid crystal alignment agent of the present invention. For example, after the liquid crystal alignment agent of the present invention is applied onto a substrate, the cured film obtained by drying and calcining may be used as a liquid crystal alignment film as it is. Further, the cured film may be subjected to rubbing, irradiation of polarized light, light of a specific wavelength, or the like, and subjected to treatment of an ion beam or the like, and irradiated with UV in a state where a voltage is applied to the liquid crystal display element after liquid crystal filling. The liquid crystal alignment agent of the present invention is useful in the case of a PSA method in which a polymerizable compound is added to a liquid crystal, or in a case where a polymerizable compound is not added to a liquid crystal.

The substrate to which the liquid crystal alignment agent is applied is not particularly limited as long as it is a substrate having high transparency, but a substrate on which a transparent electrode for driving liquid crystal is formed on the substrate is preferable.

Specific examples of the substrate include, for example, a glass plate, polycarbonate, poly(meth)acrylate, polyether oxime, polyarylate, polyurethane, polyfluorene, polyether, polyether ketone, A plastic plate such as trimethyl decene, polyolefin, polyethylene terephthalate, (meth) acrylonitrile, triethylene fluorene cellulose, diethyl phthalocyanine or cellulose acetate butyrate is formed. A substrate having a transparent electrode.

Examples of the coating method of the liquid crystal alignment agent include a spin coating method, a printing method, an inkjet method, a spray coating method, and a roll coating method. However, in terms of productivity, industrial printing is widely used. The present invention can also be suitably used.

The drying step after the application of the liquid crystal alignment agent is not necessarily required, but the time from the application to the calcination, together with the case where the substrate is not constant, or the case where the coating is not immediately calcined, is contained. The drying step is preferred. This drying is not particularly limited as long as the shape of the coating film of the substrate is not deformed by transportation or the like, and the solvent is removed. For example, a method of drying for 0.5 to 30 minutes, preferably 1 to 5 minutes, on a hot plate having a temperature of 40 to 150 ° C, preferably 60 to 100 ° C, may be mentioned.

The coating film formed by applying the liquid crystal alignment agent by the above method can be calcined to form a cured film. In this case, the calcination temperature may be carried out at any temperature of from 100 ° C to 350 ° C, but is preferably from 140 ° C to 300 ° C, more preferably from 150 ° C to 230 ° C, still more preferably from 160 ° C to 220 ° C. The calcination time can be calcined at any time from 5 minutes to 240 minutes. It is preferably from 10 to 90 minutes, more preferably from 20 to 90 minutes. For heating, a generally known method such as a hot plate, a hot air circulating oven, an IR (outside line) oven, a belt furnace or the like can be used.

The polyoxyalkylene in the liquid crystal alignment film undergoes polycondensation in the calcination step. However, in the present invention, it is not necessary to completely shrink the polymerization without impairing the effects of the present invention. However, in the liquid crystal cell manufacturing process, it is necessary to cure a sealant or the like, and it is preferable to carry out calcination at a temperature higher than the heat treatment temperature by 10 ° C or higher.

The thickness of the cured film can be selected as desired, and is preferably 5 nm or more, more preferably 10 nm or more. In this case, it is suitable because it is easy to obtain the reliability of the liquid crystal display element. Further, the thickness of the cured film is preferably 300 nm or less, more preferably 150 nm or less. In this case, since the power consumption of the liquid crystal display element does not become extremely large, it is suitable.

<Liquid crystal display element>

In the liquid crystal display device of the present invention, after the liquid crystal alignment film is formed on the substrate by the above method, a liquid crystal cell can be produced by a known method. For example, in the case of the liquid crystal cell production, a pair of substrates on which a liquid crystal alignment film has been formed is generally sandwiched by a spacer, fixed by a sealant, and the liquid crystal is injected and sealed. At this time, the size of the spacer to be formed is 1 to 30 μm, preferably 2 to 10 μm.

The method of injecting the liquid crystal is not particularly limited, and examples thereof include a vacuum method in which a liquid crystal cell is produced, a vacuum method in which a liquid crystal is injected, a dropping method in which a liquid crystal is dropped, and a sealing method.

As the liquid crystal display element of the PSA type, a liquid crystal to which a photopolymerizable compound is preferably added in a small amount (typically 0.2 to 1% by weight) can be used as the liquid crystal to be used. In the state where a voltage is applied between the electrodes of the substrates on both sides of the liquid crystal cell to which the liquid crystal is introduced, the ultraviolet ray (UV) having a wavelength of preferably 230 to 400 nm, more preferably 300 to 380 nm, due to the polymerizable compound Will be aggregated and cross-linked on the spot, the response speed of the LCD display will become faster. Here, the applied voltage is 5 to 30 Vp-p, preferably 5 to 20 Vp-p. The amount of UV irradiation to be irradiated is 1 to 60 J, preferably 40 J or less. When the amount of UV irradiation is small, the deterioration of the components constituting the liquid crystal display can be suppressed, and the UV irradiation time can be reduced by reducing the UV irradiation time. It is suitable because it can improve the time of the construction station. The liquid crystal alignment agent of the present invention can also be used for a liquid crystal display element to which no polymerizable compound is added.

The substrate used in the liquid crystal display device is not particularly limited as long as it is a substrate having high transparency, but usually, a substrate on which a transparent electrode for driving liquid crystal is formed is formed on the substrate. The specific example is the same as the substrate described in the [liquid crystal alignment film]. In the case of a PSA liquid crystal cell, the substrate may also use a standard PVA or MVA electrode pattern or a protrusion pattern. However, in the liquid crystal display of the PSA type, even if a line/slot electrode pattern of 1 to 10 μm is formed on a single-sided substrate, and a structure in which a slit pattern or a protrusion pattern is not formed on the opposite substrate, In order to be able to operate, the liquid crystal display thus constructed can simplify the process at the time of manufacture and obtain high transmittance.

Further, in a high functional element such as a TFT type element, an element such as a transistor which is driven for liquid crystal is formed between the electrode and the substrate.

In the case of a transmissive liquid crystal element, a substrate as described above is generally used. However, in the case of a reflective liquid crystal display element, if it is only a single-sided substrate, an opaque substrate such as a germanium wafer may be used. At this time, as the electrode formed on the substrate, a material such as aluminum which reflects light can also be used.

[Examples]

More specifically, the following embodiments of the present invention are described, but are not limited thereto.

The abbreviations of the compounds used in this embodiment are as follows.

TEOS: tetraethoxy decane

C18: octadecyltriethoxydecane

VTES: vinyl triethoxy decane

ARMS: allyl trimethoxy decane

OTMS: octenyl trimethoxy decane

STMS: vinyl phenyl trimethoxy decane

HG: 2-methyl-2,4-pentanediol (alias: hexanediol)

BCS: 2-butoxyethanol

UPS: 3-ureidopropyl ethoxy decane

<Synthesis Example 1>

In a 200 mL four-necked reaction flask equipped with a thermometer and a reflux tube, HG 24.0 g, BCS 8.0 g, TEOS 27.9 g, C18 1.7 g, and ARMS 9.7 g were mixed to prepare a solution of the alkoxysilane monomer. In this solution, a solution of 12.0 g of HG, 4.0 g of BCS, 10.8 g of water, and 0.9 g of oxalic acid as a catalyst, which had been previously mixed, was dropped at room temperature for 30 minutes. After the solution was refluxed for 1 hour via stirring for 30 minutes, a mixed liquid of 0.6 g of a methanol solution having a predetermined UPS content of 92% by mass, 0.3 g of HG, and 0.1 g of BCS was added. Further, after refluxing, the mixture was allowed to cool after 30 minutes to obtain a polysiloxane solution having a SiO ₂ conversion concentration of 12% by weight.

To 10.0 g of the obtained polysiloxane solution, 20.0 g of BCS was mixed to obtain a liquid crystal alignment agent (K1) having a SiO ₂ conversion concentration of 4% by weight.

<Synthesis Example 2>

In a 200 mL four-necked reaction flask equipped with a thermometer and a reflux tube, HG 21.6 g, BCS 7.2 g, TEOS 27.5 g, C18 1.7 g, and OTMS 13.9 g were mixed to prepare a solution of the alkoxysilane monomer. In this solution, a solution of 10.8 g of HG, 3.6 g of BCS, 10.8 g of water, and 0.9 g of oxalic acid as a catalyst, which had been previously mixed, was dropped at room temperature for 30 minutes. After the solution was refluxed for 1 hour via stirring for 30 minutes, a mixed solution of 1.2 g of a methanol solution having a predetermined UPS content of 92% by mass, 0.6 g of HG, and 0.2 g of BCS was added. Further, after refluxing, the mixture was allowed to cool after 30 minutes to obtain a polysiloxane solution having a SiO ₂ conversion concentration of 12% by weight.

To 10.0 g of the obtained polyoxane solution, 20.0 g of BCS was mixed to obtain a liquid crystal alignment agent (K2) having a SiO ₂ conversion concentration of 4% by weight.

<Synthesis Example 3>

In a 200 mL four-necked reaction flask equipped with a thermometer and a reflux tube, 21.8 g of HG, 7.3 g of BCS, 27.5 g of TEOS, 1.7 g of C18, and 13.5 g of STMS were mixed to prepare a solution of alkoxysilane monomer. In this solution, a solution of 10.9 g of HG, 3.6 g of BCS, 10.8 g of water, and 0.9 g of oxalic acid as a catalyst, which had been previously mixed, was dropped at room temperature for 30 minutes. After the solution was refluxed for 1 hour via stirring for 30 minutes, a mixed solution of 1.2 g of a methanol solution having a predetermined UPS content of 92% by mass, 0.6 g of HG, and 0.2 g of BCS was added. Further, after refluxing, the mixture was allowed to cool after 30 minutes to obtain a polysiloxane solution having a SiO ₂ conversion concentration of 12% by weight.

To 10.0 g of the obtained polyoxane solution, 20.0 g of BCS was mixed to obtain a liquid crystal alignment agent (K3) having a SiO ₂ conversion concentration of 4% by weight.

<Comparative Synthesis Example 1>

In a 200 mL four-necked reaction flask equipped with a thermometer and a reflux tube, HG 23.3 g, BCS 7.7 g, TEOS 40.8 g, and C18 1.7 g were mixed to prepare a solution of the alkoxysilane monomer. In this solution, a solution of 11.6 g of HG, 3.9 g of BCS, 10.8 g of water, and 0.2 g of oxalic acid as a catalyst, which had been previously mixed, was dropped at room temperature for 30 minutes. This solution was stirred for 30 minutes, and the mixture was refluxed for 1 hour, and then allowed to cool to obtain a polyoxyalkylene solution having a concentration of SiO ₂ of 12% by weight.

To 10.0 g of the obtained polysiloxane solution, 20.0 g of BCS was mixed to obtain a liquid crystal alignment agent (L1) having a SiO ₂ conversion concentration of 4% by weight.

<Comparative Synthesis Example 2>

In a 200 mL four-necked reaction flask equipped with a thermometer and a reflux tube, HG 21.8 g, BCS 7.3 g, TEOS 27.5 g, C18 1.7 g, and VTES 13.5 g were mixed to prepare a solution of the alkoxysilane monomer. In this solution, a solution of 10.9 g of HG, 3.6 g of BCS, 10.8 g of water, and 0.9 g of oxalic acid as a catalyst, which had been previously mixed, was dropped at room temperature for 30 minutes. After the solution was refluxed for 1 hour via stirring for 30 minutes, a mixed solution of 1.2 g of a methanol solution having a predetermined UPS content of 92% by mass, 0.6 g of HG, and 0.2 g of BCS was added. Further, after refluxing, the mixture was allowed to cool after 30 minutes to obtain a polysiloxane solution having a SiO ₂ conversion concentration of 12% by weight.

To 10.0 g of the obtained polyoxane solution, 20.0 g of BCS was mixed to obtain a liquid crystal alignment agent (L2) having a SiO ₂ conversion concentration of 4% by weight.

<Example 1>

The liquid crystal alignment treatment agent [K1] obtained in Synthesis Example 1 was spin-coated on an ITO surface of an ITO electrode substrate having a pixel size of 100 μm × 300 μm and an ITO electrode pattern having a line/space of 5 μm. After drying for 5 minutes on a hot plate at 80 ° C, the film was calcined in a hot air circulating oven at 180 ° C for 30 minutes to form a liquid crystal alignment film having a film thickness of 100 nm.

The liquid crystal alignment treatment agent [K1] obtained in Synthesis Example 1 was spin-coated on an ITO surface on which no electrode pattern was formed, and dried on a hot plate at 80 ° C for 5 minutes, and then subjected to a hot air circulating oven at 180 ° C. The calcination was carried out for 30 minutes to form a liquid crystal alignment film having a film thickness of 100 nm. These two substrates were prepared, and a 6 μm bead spacer was spread on the liquid crystal alignment film surface of one of the substrates, and then a sealant was printed thereon. The liquid crystal alignment film surface of the other substrate is made to be inside, and after bonding, the sealing agent is cured to form an empty cell. The liquid crystal MLC-6608 (trade name, manufactured by Mok Corporation) was injected into the empty cell by a vacuum injection method to produce a liquid crystal cell.

The response speed characteristics of these liquid crystal cells are measured by the method described later. Thereafter, this liquid crystal cell was subjected to a voltage application state of 20 Vp-p, whereby UV (wavelength: 280 to 330 nm) 20 J was irradiated to the outside of the liquid crystal cell. Thereafter, the response speed characteristics were measured again, and the response speed before and after the UV irradiation was compared. The results are shown in Table 1.

<Example 2>

A liquid crystal cell was produced in the same manner as in Example 1 except that the liquid crystal alignment treatment agent [K1] was changed to the liquid crystal alignment treatment agent [K2] obtained in Synthesis Example 2, and the response speed was measured. The results are shown in Table 1.

<Example 3>

A liquid crystal cell was produced in the same manner as in Example 1 except that the liquid crystal alignment agent [K1] was changed to the liquid crystal alignment treatment agent [K3] obtained in Synthesis Example 3, and the response speed was measured. The results are shown in Table 1.

<Comparative Example 1>

A liquid crystal cell was produced in the same manner as in Examples 1 to 3 except that the liquid crystal alignment agent [K1] was changed to the liquid crystal alignment treatment agent [L1] obtained in Comparative Synthesis Example 1, and the response speed was measured. The results are shown in Table 1.

<Comparative Example 2>

A liquid crystal cell was produced in the same manner as in Examples 1 to 3 except that the liquid crystal alignment agent [K1] was changed to the liquid crystal alignment treatment agent [L2] obtained in Comparative Synthesis Example 2, and the response speed was measured. The results are shown in Table 1.

[response speed characteristics]

For a liquid crystal cell to which no voltage is applied, the luminance-time change of the liquid crystal panel is read using an oscilloscope when a rectangular wave of a voltage of ±4 V and a frequency of 1 kHz is applied. When the luminance is not applied as 0%, the voltage of ±4V is applied and the value of the saturation luminance is taken as 100%, and the time when the luminance is changed from 10% to 90% is used as the response speed of the rise (unit: micro second).

As can be seen from Table 1, in the liquid crystal cell of the example, even when a liquid crystal to which no polymerizable compound was added was used, the response speed after UV irradiation was improved. On the other hand, in the comparative example, the response speed did not increase before and after the UV irradiation.

[Industry Utilization]

In the case where the liquid crystal alignment agent of the present invention is a PSA method in which a polymerizable compound is added, or a liquid crystal in which a polymerizable compound is not added, the response speed is improved and a good alignment state can be obtained. The liquid crystal display element produced by the liquid crystal alignment agent of the invention is useful as a TFT liquid crystal display element, a TN liquid crystal display element, a VA liquid crystal display element, or the like.

Claims (10)

A liquid crystal alignment agent comprising a polyoxyalkylene obtained by polycondensing an alkoxysilane containing an alkoxydecane represented by the formula (1) and an alkoxysilane represented by the formula (2); R ¹ Si (OR ^{2 )} ₃ (1) (R ¹ is a hydrocarbon group having 8 to 30 carbon atoms which may be substituted by a fluorine atom, and R ² is an alkyl group having 1 to 5 carbon atoms), R ³ is represented by the following formula (3) (except that m and n are each an integer of 0 to 6), and R ⁴ is represented by an alkyl group having 1 to 5 carbon atoms. The liquid crystal alignment agent of the first aspect of the invention, wherein the polyoxyalkylene oxide further comprises a polyoxyalkylene obtained by polycondensation of an alkoxysilane having an alkoxydecane represented by the following formula (4), (R ⁵ _n Si(OR ⁶ ) _4-n (4) (R ⁵ is a hydrogen atom or a carbon which may be substituted by a hetero atom, a halogen atom, an amine group, a glycidoxy group, a decyl group, an isocyanate group or a urea group) A hydrocarbon group having 1 to 6 atoms, R ⁶ is an alkyl group having 1 to 5 carbon atoms, and n is an integer of 0 to 3). The liquid crystal alignment agent of the second aspect of the invention, wherein n of the formula (4) is 0, and the alkoxydecane-based tetraalkane alkane represented by the above formula (4). The liquid crystal alignment agent of claim 1, wherein the polyoxyalkylene oxide is contained in the peralkyl alkane with 0.1 to 30 mol% of the alkoxysilane represented by the formula (1), and is in the total alkoxylate. The decane is obtained by polycondensation of an alkoxysilane containing 3 to 70 mol% of the alkoxydecane represented by the above formula (2). The liquid crystal alignment agent of claim 2, wherein the polyoxyalkylene is condensed and polymerized in a peralkyl alkane with an alkoxy decane having an alkoxydecane of 10 to 96.9 mol% represented by the formula (4). Obtained. The liquid crystal alignment agent according to any one of the first to fifth aspects of the present invention, wherein the content of the polysiloxane is 0.5 to 15% by mass in terms of SiO ₂ conversion. A liquid crystal alignment film obtained by applying a liquid crystal alignment agent according to any one of claims 1 to 6 to a substrate, drying, and calcining. A liquid crystal display element having a liquid crystal alignment film according to item 7 of the patent application. A liquid crystal display element which is coated with a liquid crystal alignment agent according to any one of claims 1 to 6 to two substrates, and for holding a liquid crystal cell of liquid crystal using two substrates which have been calcined, UV is irradiated in a state where a voltage is applied. A method of manufacturing a liquid crystal display element, which is applied as a coating The liquid crystal alignment agent according to any one of the first to sixth aspects of the invention, wherein the liquid crystal is held by using two substrates which have been calcined, and UV is irradiated in a state of applying a voltage.