KR20130040847A - Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Abstract

(R³ 은, 탄소 원자수 1 ～ 18 의 탄화수소기이고, R⁴ 는 탄소수 1 ～ 5 의 알킬기를 나타낸다)When a polymeric compound is added to a liquid crystal, or when it is not added, the response speed improves and the liquid crystal aligning agent for obtaining the liquid crystal aligning film for liquid crystal display elements from which a favorable orientation state is obtained is provided.
The liquid crystal aligning agent containing the polysiloxane obtained by polycondensing the alkoxysilane represented by Formula (1) and the alkoxysilane represented by Formula (2).
R ¹ Si (OR ² ) ₃ (1)
(R ¹ may be substituted with a fluorine atom, is a hydrocarbon group having 8 to 30 carbon atoms, and R ² represents an alkyl group having 1 to 5 carbon atoms)
[Formula 1]

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

Description

Liquid crystal aligning agent, liquid crystal aligning film, and liquid crystal display element {LIQUID CRYSTAL ALIGNING AGENT, LIQUID CRYSTAL ALIGNMENT FILM AND LIQUID CRYSTAL DISPLAY ELEMENT}

This invention relates to the liquid crystal aligning agent containing the polysiloxane obtained by polycondensing an alkoxysilane, the liquid crystal aligning film obtained from this liquid crystal aligning agent, and the liquid crystal display element which has this liquid crystal aligning film.

In recent years, the vertical (VA) type liquid crystal display element is widely used among the display system of a liquid crystal display element, such as a big screen liquid crystal television and high-precision mobile use (display part of a digital camera or a mobile telephone). In the VA method, an MVA method (Multi Vertical Alignment) in which projections for controlling the liquid crystal fall direction is formed on a TFT substrate or a color filter substrate, or a direction in which the liquid crystal falls by an electric field by forming slits in the ITO electrode of the substrate. A PVA (Paterned Vertical Alignment) method of controlling is known.

As another VA orientation system, there is a PSA (Polymer sustained Alignment) system. Among the VA methods, the PSA method is a technique that has recently attracted attention. This system normally adds a photopolymerizable compound to a liquid crystal, and irradiates an ultraviolet-ray (UV) to a liquid crystal in the state which a liquid crystal fell by applying an electric field after manufacture of a liquid crystal panel. Thereby, when the polymeric compound photopolymerizes, the orientation direction of a liquid crystal is fixed, pretilt generate | occur | produces and a response speed improves. In PSA system, a slit is manufactured in the electrode of the one side which comprises a liquid crystal panel, and it can operate even in the structure which does not form the processus | protrusion in case of MVA system and the slit in case of PVA system to the electrode pattern of the opposite side, and manufactures It has the feature that simplification and excellent panel transmittance are obtained (refer patent document 1).

On the other hand, an inorganic liquid crystal aligning film material is also known with organic liquid crystal aligning film materials, such as polyimide conventionally used. For example, as a material of the coating type inorganic alignment film, the composition containing the reaction product of tetraalkoxysilane, a trialkoxysilane, alcohol, and oxalic acid is used, and the vertical alignment property, heat resistance, and uniformity on the electrode substrate of a liquid crystal display element. It is reported to form the liquid crystal aligning film excellent in the property (refer patent document 2).

Moreover, by using the liquid crystal aligning agent composition containing the tetraalkoxysilane, the reaction product with specific trialkoxysilane, water, and the specific glycol ether type solvent, display defect is prevented and a liquid crystal is orientated without leaving an afterimage after long time driving. It is reported to form the liquid crystal aligning film with little fall of the voltage retention with respect to light and heat, without reducing the ability to make it (refer patent document 3).

Japanese Unexamined Patent Publication No. 2004-302061 Japanese Patent Application Laid-Open No. 09-281502 Japanese Laid-Open Patent Publication 2005-250244

Conventionally, in the liquid crystal display element of a PSA system, there exists a problem that the solubility of the polymeric compound added to a liquid crystal is low, and when an addition amount is increased, it will precipitate at low temperature. On the other hand, when the addition amount of a polymeric compound is reduced, a favorable orientation state will no longer be obtained. Moreover, since the unreacted polymeric compound which remains in a liquid crystal turns into an impurity (contamination) in a liquid crystal, there exists a problem of reducing the reliability of a liquid crystal display element.

The problem of the present invention is that even when the amount of the polymerizable compound added to the liquid crystal is small in the PSA system, even when a liquid crystal without the polymerizable compound is used, the response speed is improved to obtain a good alignment state. It is possible to provide a liquid crystal display element having a liquid crystal aligning agent for a liquid crystal display element, a liquid crystal aligning film obtained from the liquid crystal aligning agent, and the liquid crystal aligning film.

This invention makes the following a summary.

[1] A polysiloxane obtained by polycondensing an alkoxysilane represented by the formula (1) and an alkoxysilane represented by the formula (2), wherein the liquid crystal aligning agent for an element is characterized.

R ¹ Si (OR ² ) ₃ (1)

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

[Formula 1]

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

[2] The liquid crystal aligning agent according to the above [1], wherein R ^{3 in} the formula (2) is an alkylene group.

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

[Formula 2]

[4] The liquid crystal aligning agent according to any one of the above [1] to [3], wherein the polysiloxane is a polysiloxane obtained by polycondensing an alkoxysilane containing an alkoxysilane represented by the following formula (4).

(R ⁵ ) _n Si (OR ⁶ ) _4-n (4)

(R ⁵ is a hydrocarbon group having 1 to 6 carbon atoms which may be substituted with a hydrogen atom, a hetero atom, a halogen atom, an amino group, a glycidoxy group, a mercapto group, an isocyanate group or a ureido group, and R ⁶ is An alkyl group having 1 to 5 carbon atoms, n represents an integer of 0 to 3)

[5] The liquid crystal aligning agent according to the above [4], wherein the alkoxysilane represented by the formula (4) is a tetraalkoxysilane where n in the formula (4) is 0.

[6] The polysiloxane contains 0.1 to 30 mol% of the alkoxysilane represented by the formula (1) in all the alkoxysilanes, and 3 to 70 mol% of the alkoxysilane represented by the formula (2). The liquid crystal aligning agent in any one of said [1]-[5] obtained by polycondensing the alkoxysilane to contain.

[7] The liquid crystal aligning agent according to any one of the above [4] to [6], wherein the polysiloxane polycondenses an alkoxysilane containing 10 to 96.9 mol% of the alkoxysilane represented by the formula (4) in all alkoxysilanes. .

[8] The liquid crystal aligning agent according to any one of the above [1] to [7], in which the content of polysiloxane is 0.5 to 15% by mass in terms of SiO ₂ .

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

[10] A liquid crystal display device having the liquid crystal alignment film according to the above [9].

[11] A liquid crystal display device wherein the liquid crystal aligning agent according to any one of the above [1] to [8] is applied and UV is irradiated in a state where voltage is applied to a liquid crystal cell in which liquid crystal is sandwiched by two baked substrates.

[12] A method for producing a liquid crystal display device wherein the liquid crystal aligning agent according to any one of the above [1] to [8] is applied, the liquid crystal is sandwiched by two baked substrates, and UV is irradiated in a state where a voltage is applied. .

According to the liquid crystal aligning agent of this invention, even when the quantity of the polymeric compound added to a liquid crystal in a PSA system is small, also when using the liquid crystal which does not add a polymeric compound, response speed improves and favorable orientation is carried out. The display element which has the liquid crystal aligning film for liquid crystal display elements which can obtain a state, and this liquid crystal aligning film is obtained.

Hereinafter, the present invention will be described in detail.

[Polysiloxane]

This invention is the liquid crystal aligning agent for PSA systems containing polysiloxane obtained by polycondensing the alkoxysilane represented by Formula (1) and the alkoxysilane represented by 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 with a fluorine atom, and R ² represents an alkyl group having 1 to 5 carbon atoms. In addition, in this specification, "may be substituted" means "substituted or not substituted."

(3)

R <^3> is a C1-C18 hydrocarbon group and R <^4> represents a C1-C5 alkyl group.

R ¹ (hereinafter also referred to as a specific organic group) of the alkoxysilane represented by formula (1) is a hydrocarbon group having 8 to 30, preferably 8 to 22 carbon atoms, which may be substituted with fluorine, and the liquid crystal is vertically It will not specifically limit, if it has an effect to orientate. Examples thereof include an alkyl group, a fluoroalkyl group, an alkenyl group, a phenethyl group, a styrylalkyl group, a naphthyl group, a fluorophenylalkyl group, and the like. Among these, the alkoxysilane whose R <^1> is an alkyl group or a fluoroalkyl group is preferable because it is easy to obtain as a commercial item at comparatively low cost. In particular, the alkoxysilane whose R <^1> is an alkyl group is preferable. The polysiloxane used for this invention may have two or more types of these specific organic groups.

R <^2> of the alkoxysilane represented by Formula (1) is C1-C5, Preferably it is an alkyl group of 1-3. More preferably, R ² is a methyl group or an ethyl group.

Although the specific example of the alkoxysilane represented by such Formula (1) is given, it is not limited to this.

For example, octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltrimethoxysilane, hexa Decyltriethoxysilane, heptadecyltrimethoxysilane, heptadecyltriethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, nonadecyltrimethoxysilane, nonadecyltriethoxysilane, undecyl Triethoxysilane, undecyltrimethoxysilane, 21-docosenyltriethoxysilane, tridecafluorooctyltrimethoxysilane, tridecafluorooctyltriethoxysilane, heptadecafluorodecyltrimethoxysilane , Heptadecafluorodecyltriethoxysilane, isooctyltriethoxysilane, phenethyltriethoxysilane, pentafluorophenylpropyltrimethoxysilane, m-styrylethyltrimethoxysilane, p-styrylethyltrimeth Oxysilane, (1-I Til) tree in the silane, (1-naphthyl) and the like can be mentioned trimethoxysilane. Among them, octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyl Triethoxysilane, Heptadecyltrimethoxysilane, Heptadecyltriethoxysilane, Octadecyltrimethoxysilane, Octadecyltriethoxysilane, Nonadecyltrimethoxysilane, Nonadecyltriethoxysilane, Undecyltree Ethoxysilane or undecyltrimethoxysilane is preferable.

In the alkoxysilane represented by Formula (1) which has the specific organic group mentioned above, in all the alkoxysilanes used in order to obtain polysiloxane, 0.1 mol% or more is preferable in order to acquire favorable liquid-crystal orientation. More preferably, it is 0.5 mol% or more. More preferably, it is 1 mol% or more. Moreover, in order to acquire sufficient hardening characteristic of the liquid crystal aligning film formed, 30 mol% or less is preferable. More preferably, it is 22 mol% or less.

R ³ (hereinafter also referred to as a second specific organic group) of the alkoxysilane represented by formula (2) is a hydrocarbon group having 1 to 18 carbon atoms, preferably 1 to 12 carbon atoms, and an aliphatic hydrocarbon; an aliphatic ring or an aromatic ring. And a ring structure such as a hetero ring; and a hetero atom such as an oxygen atom, a nitrogen atom, a sulfur atom, or the like. Preferably they are an alkylene group and a phenylene group. The number of carbon atoms in the alkylene group is 1-18, More preferably, it is 1-12. A phenylene group is represented by following formula (3), m and n are integers of 0-6, respectively, Preferably they are integers of 0-2.

[Formula 4]

R <^4> of the alkoxysilane represented by Formula (2) is the same as that of the definition of R <^2> in said Formula (1), and the same as that of the preferable R <^2> of R <^4> .

Although the specific example of the alkoxysilane represented by Formula (2) is given, it is not limited to these. For example, allyltrimethoxysilane, allyltriethoxysilane, butenyltrimethoxysilane, butenyltriethoxysilane, pentenyltrimethoxysilane, pentenyltriethoxysilane, hexynyltrimethoxysilane , Hexynyltriethoxysilane, heptenyltrimethoxysilane, heptenyltriethoxysilane, octenyltrimethoxysilane, octenyltriethoxysilane, undecynyltrimethoxysilane, undecynyltriethoxy Silane, allyloxyundecyltrimethoxysilane, allyloxyundecyltriethoxysilane, vinylphenyltrimethoxysilane, vinylphenyltriethoxysilane, vinylphenylethyltrimethoxysilane, vinylphenylethyltriethoxysilane, etc. Can be mentioned.

In the case of a small amount of the polymerizable compound added to the liquid crystal in the PSA system, and even when a liquid crystal not added with the polymerizable compound is used, in order to improve the response speed of the liquid crystal display element, the second specific organic group As for the alkoxysilane represented by Formula (2), 3 mol% or more is preferable in all the alkoxysilanes used in order to obtain polysiloxane. More preferably, it is 5 mol% or more. More preferably, it is 10 mol% or more. Moreover, in order to fully harden the liquid crystal aligning film formed, 70 mol% or less is preferable.

In the present invention, the alkoxysilane represented by the formula (1) is preferably 0.1 to 30 mol%, particularly preferably 2 to 20 mol%, of all alkoxysilanes used, and alkoxy represented by the formula (2) It is preferable to contain 3-30 mol%, Especially preferably, 5-30 mol% of all the alkoxysilanes in which a silane is used.

In this invention, when obtaining polysiloxane, the alkoxysilane represented by following formula (4) can also be used other than the alkoxysilane represented by Formula (1) and Formula (2). Since the alkoxysilane represented by Formula (4) can give various characteristics to polysiloxane, 1 type or multiple types can be selected and used according to a required characteristic.

(R ⁵ ) _n Si (OR ⁶ ) _4-n (4)

R <^5> is a C1-C6 hydrocarbon group which may be substituted by the hydrogen atom, the hetero atom, the halogen atom, the amino group, the glycidoxy group, the mercapto group, the isocyanate group, or the ureido group. R <^6> is C1-C5, Preferably it is an alkyl group of 1-3, n is 0-3, Preferably it represents the integer of 0-2.

R ⁵ of the alkoxysilane 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; an aliphatic ring, an aromatic ring, a ring structure such as a hetero ring; an unsaturated bond; a hetero atom such as an oxygen atom, a nitrogen atom, a sulfur atom, etc., and may have a branched structure. It is the organic group which may have 1-6 carbon atoms. The organic group may be substituted with a halogen atom, an amino group, a glycidoxy group, a mercapto group, an isocyanate group, a ureido group, or the like.

Although the specific example of the alkoxysilane represented by Formula (4) is given, it is not limited to this.

In the alkoxysilane of Formula (4), a trimethoxysilane, a triethoxysilane, a tripropoxysilane, a tributoxysilane etc. are mentioned as a specific example of the alkoxysilane when R <^5> is a hydrogen atom. .

Moreover, in the alkoxysilane of Formula (4), as a specific example of the alkoxysilane when R <^5> is a 3rd organic group, Methyl trimethoxysilane, methyl triethoxysilane, ethyl trimethoxysilane, and ethyl trie Methoxysilane, propyltrimethoxysilane, propyltriethoxysilane, methyltripropoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2 (aminoethyl) 3-aminopropyl Triethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, 3- (2-aminoethylaminopropyl) trimethoxysilane, 3- (2-aminoethylaminopropyl) triethoxysilane , 2-aminoethylaminomethyltrimethoxysilane, 2- (2-aminoethylthio ethyl) triethoxysilane, 3-mercaptopropyltriethoxysilane, mercaptomethyltrimethoxysilane, vinyltriethoxysilane , 3-isocyanatepropyltriethoxysilane, trifluoropropyltrimethoxysilicone , Chloropropyltriethoxysilane, bromopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, diethyldiethoxysilane, diethyldimethoxysilane, diphenyl Dimethoxysilane, diphenyldiethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyldimethylethoxysilane, trimethylethoxysilane, trimethylmethoxysilane, γ-ureidopropyltriethoxysilane, γ- Ureidopropyltrimethoxysilane, γ-ureidopropyltripropoxysilane, and the like.

The polysiloxane used for this invention uses the alkoxysilane represented by said formula (4) as long as the effect of this invention is not impaired for the purpose of improving adhesiveness with a board | substrate, affinity with a liquid crystal molecule, etc. You may have a species or multiple types.

In the alkoxysilane represented by Formula (4), the alkoxysilane whose n is 0 is tetraalkoxysilane. Since tetraalkoxysilane is easy to condense with the alkoxysilane represented by Formula (1) and Formula (2), it is preferable in order to obtain the polysiloxane of this invention.

As the alkoxysilane in which n is 0 in the formula (4), tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane or tetrabutoxysilane is more preferable, and tetramethoxysilane or tetra Lt; / RTI &gt; is preferred.

When using the alkoxysilane represented by Formula (4) together, it is preferable that the usage-amount of the alkoxysilane represented by Formula (4) is 10-96.9 mol% in all the alkoxysilanes used in order to obtain polysiloxane. More preferably, it is 35-99.8 mol%.

[Method for producing polysiloxane]

The method for obtaining the polysiloxane used in the present invention is not particularly limited. In this invention, it is obtained by condensing the alkoxysilane which makes said formula (1) and formula (2) an essential component in an organic solvent. Usually, polysiloxane polycondenses such alkoxysilane and is obtained as a solution which melt | dissolved uniformly in the organic solvent.

As a method of polycondensing polysiloxane, the method of hydrolyzing and condensing an alkoxysilane in solvent, such as alcohol or glycol, is mentioned, for example. At this time, the hydrolysis-condensation reaction may be partial hydrolysis or complete hydrolysis. In the case of complete hydrolysis, theoretically, 0.5 times mole of water of all the alkoxy groups in an alkoxysilane may be added, but it is preferable to add excess water more than 0.5 times mole normally.

In this invention, although the quantity of the water used for the said reaction can be suitably selected as desired, Usually, it is preferable that it is 0.5-2.5 times mole of all the alkoxy groups in an alkoxysilane.

Normally, hydrochloric acid, sulfuric acid, nitric acid, acetic acid, formic acid, oxalic acid, maleic acid, fumaric acid and the like; ammonia, methylamine, ethylamine, ethanolamine, triethylamine, etc., for the purpose of promoting hydrolysis and condensation reactions. Alkali; metal salts such as hydrochloric acid, sulfuric acid, nitric acid; and the like catalyst is used. Moreover, it is also common to accelerate hydrolysis and condensation reaction by heating the solution which the alkoxysilane melt | dissolved. At that time, the heating temperature and the heating time can be appropriately selected as desired. For example, the method of heating and stirring at 50 degreeC for 24 hours under heating and stirring, and refluxing is mentioned.

Moreover, the method of heating and polycondensing the mixture of an alkoxysilane, a solvent, and oxalic acid as another method is mentioned, for example. Specifically, oxalic acid is added to the alcohol in advance to form an alcohol solution of oxalic acid, and then the alkoxysilane is mixed while the solution is heated. In that case, it is preferable that the quantity of the oxalic acid to be used shall be 0.2-2 mol with respect to 1 mol of all the alkoxy groups which an alkoxysilane has. Heating in this method can be performed at liquid temperature of 50-180 degreeC. Preferably, it is a method of heating from several tens of minutes to several tens of hours under reflux so that evaporation, volatilization, etc. of a liquid do not occur.

When obtaining a polysiloxane, when using multiple types of alkoxysilanes, you may use as a mixture which mixed the alkoxysilane previously, and may mix several types of alkoxysilanes one by one.

The solvent used for polycondensing the alkoxysilane (hereinafter also referred to as a polymerization solvent) is not particularly limited as long as it dissolves the alkoxysilane. Moreover, what is necessary is just to melt | dissolve with advancing of the polycondensation reaction of an alkoxysilane, even if an alkoxysilane does not melt | dissolve. Generally, since alcohol is produced by the polycondensation reaction of an alkoxysilane, the favorable organic solvent compatible with alcohol, glycol, glycol ether, or alcohol is 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, hexylene glycol, 1,3-propanediol , 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5- Glycols such as pentanediol, 2,4-pentanediol, 2,3-pentanediol, 1,6-hexanediol: ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl Ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol mono Butyl ether, die Ethylene 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, Glycol ethers such as propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, and propylene glycol dibutyl ether, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N- Dimethylacetamide, γ-butyrolactone, dimethyl sulfoxide, tetramethylurea, hexamethylphosphotriamide, m-cresol and the like.

In the present invention, a plurality of the polymerization solvents may be mixed and used.

The polymerization solution (hereinafter also referred to as polymerization solution) of the polysiloxane obtained by the above method is preferably a concentration (hereinafter referred to as SiO ₂ conversion concentration) in which silicon atoms of all alkoxysilanes injected as raw materials are converted into SiO ₂ . 20 mass% or less, Furthermore, it is more preferable to set it as 5-15 mass%. By selecting an arbitrary concentration in this concentration range, formation of a gel can be suppressed to obtain a homogeneous solution.

[Solution of Polysiloxane]

In the present invention, the polymerization solution obtained by the above method may be used as a solution of polysiloxane as it is, and if necessary, the solution obtained by the above method is concentrated, diluted with the addition of a solvent, or substituted with another solvent to obtain a polysiloxane. It is good also as a solution.

In that case, the solvent (henceforth an addition solvent) to be used may be the same as a polymerization solvent, and may be another solvent. This addition solvent is not specifically limited as long as polysiloxane is melt | dissolving uniformly, One type or multiple types can also be selected arbitrarily, and can be used.

Specific examples of such additive solvents include ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; esters such as methyl acetate, ethyl acetate, and ethyl lactate, in addition to the solvents mentioned as examples of the polymerization solvent described above. have.

These solvents can improve the applicability | paintability at the time of apply | coating a liquid crystal aligning agent on a board | substrate by adjustment of the viscosity of a liquid crystal aligning agent, or spin coating, flexographic printing, an inkjet, etc.

[Other Ingredients]

In the present invention, components other than polysiloxane, such as inorganic fine particles, metal siloxane oligomers, metal siloxane polymers, leveling agents, and surfactants, are contained unless the effect of the present invention is impaired. You may be.

As the inorganic fine particles, fine particles such as silica fine particles, alumina fine particles, titania fine particles, or magnesium fluoride fine particles are preferable, and in particular, they are preferably in a colloidal solution state. This colloidal solution may disperse | distribute an inorganic fine particle in a dispersion medium, and may be a colloidal solution which is a commercial item. In this invention, by containing an inorganic fine particle, it becomes possible to change the surface shape of the cured film formed, or to provide another function. As the inorganic fine particles, the average particle diameter is preferably 0.001 to 0.2 µm, more preferably 0.001 to 0.1 µm. When the average particle diameter of an inorganic fine particle exceeds 0.2 micrometer, transparency of the cured film formed using the coating liquid prepared may fall.

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

Examples of the organic solvent used in the dispersion medium of the colloidal solution include alcohols such as methanol, propanol, butanol, ethylene glycol, propylene glycol, butanediol, pentanediol, hexylene glycol, diethylene glycol, dipropylene glycol, and ethylene glycol monopropyl ether. Ketones such as methyl ethyl ketone and methyl isobutyl ketone; aromatic hydrocarbons such as toluene and xylene; amides such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone; ethyl acetate, butyl acetate and γ- Esters such as butyrolactone; ethers such as tetrahydrofuran and 1,4-dioxane. Among these, alcohols or ketones are preferable. These organic solvents may be used alone or as a dispersion medium by mixing two or more kinds thereof.

As the metal siloxane oligomer and the metal siloxane polymer, single or complex oxide precursors such as silicon, titanium, aluminum, tantalum, antimony, bismuth, tin, indium and zinc are used. As a metal siloxane oligomer and a metal siloxane polymer, a commercial item may be sufficient and it may be what was obtained by conventional methods, such as hydrolysis, from monomers, such as a metal alkoxide, a nitrate, a hydrochloride, and a carboxylate.

Examples of commercially available metal siloxane oligomers and metal siloxane polymers include siloxane oligomers and siloxanes such as methyl silicate 51, methyl silicate 53A, ethyl silicate 40, ethyl silicate 48, EMS-485, and SS-101 manufactured by Colcot Co., Ltd. Titanoic acid oligomers, such as a polymer and the titanium-n-butoxide tetramer made by Canto Chemical Company, are mentioned. These may be used alone or in combination of two or more.

As the leveling agent and the surfactant, known ones can be used, and commercial products are particularly preferable since they are readily available.

Moreover, the method of mixing said other components with polysiloxane may be simultaneous with polysiloxane, and may be subsequent and is not specifically limited.

[Liquid crystal aligning agent]

The liquid crystal aligning agent of this invention is a solution containing the above-mentioned polysiloxane and other components as needed. At this time, as the solvent, a solvent selected from the group consisting of a polymerization solvent of the above-mentioned polysiloxane and an addition solvent is used. As for content of polysiloxane in a liquid crystal aligning agent, SiO ₂ conversion density | concentration becomes like this. Preferably it is 0.5-15 mass%, More preferably, it is 1-6 mass%. In a range of concentration in terms of SiO _2, and easily obtain a desired film thickness by one time of coating, it tends to be a sufficient solution of the pot life is obtained.

The method for preparing the liquid crystal aligning agent of the present invention is not particularly limited. What is necessary is just the state which the polysiloxane used for this invention and the other component added as needed mixed uniformly. Usually, since polysiloxane polycondenses in a solvent, it is easy to use the solution of polysiloxane as it is, or to add another component to the solution of polysiloxane as needed. The most convenient method is to use the polymerization solution of polysiloxane as it is.

Moreover, when adjusting content of the polysiloxane in a liquid crystal aligning agent, the solvent chosen from the group which consists of the polymerization solvent and addition solvent of the polysiloxane mentioned above can be used.

[Liquid Crystal Alignment Layer]

The liquid crystal aligning film of this invention is obtained using the liquid crystal aligning agent of this invention. For example, after apply | coating the liquid crystal aligning agent of this invention to a board | substrate, the cured film obtained by performing drying and baking can also be used as a liquid crystal aligning film as it is. It is also possible to rub the cured film, to irradiate polarized light, light of a specific wavelength or the like, to treat ion beams or the like, or to apply UV to the liquid crystal display element after the liquid crystal is charged. The liquid crystal aligning agent of this invention is useful also in the case of the PSA system in which a polymeric compound is added to a liquid crystal, and also when a polymeric compound is not added to a liquid crystal.

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

Specific examples of the substrate include glass plates, polycarbonates, poly (meth) acrylates, polyethersulfones, polyarylates, polyurethanes, polysulfones, polyethers, polyetherketones, trimethylpentene, polyolefins, polyethylene terephthalates, ( The board | substrate with which a transparent electrode was formed in plastic plates, such as a meth) acrylonitrile, a triacetyl cellulose, a diacetyl cellulose, an acetate butyrate cellulose, is mentioned.

As a coating method of a liquid crystal aligning agent, a spin coat method, the printing method, the inkjet method, the spray method, the roll coating method, etc. are mentioned, In terms of productivity, the transfer printing method is widely used industrially, and also in this invention It is preferably used.

The step of drying after applying the liquid crystal aligning agent is not necessarily required. However, when the time from the application to the firing is not constant for each substrate or when the firing is not performed immediately after the application, it is preferable to include a drying step. The solvent should just be removed to such an extent that a coating-film shape does not deform | transform by conveyance of a board | substrate etc., and this drying is not specifically limited about the drying means. For example, the method of drying for 0.5 to 30 minutes, Preferably 1 to 5 minutes is mentioned on the hotplate of temperature 40 degreeC-150 degreeC, Preferably 60 degreeC-100 degreeC.

The coating film formed by applying the liquid crystal aligning agent by the above method can be fired to form a cured film. In that case, baking temperature can be implemented at arbitrary temperature of 100 degreeC-350 degreeC, Preferably it is 140 degreeC-300 degreeC, More preferably, it is 150 degreeC-230 degreeC, More preferably, 160 degreeC-220 degreeC to be. Firing time can be baked in arbitrary time for 5 minutes-240 minutes. Preferably it is 10 to 90 minutes, More preferably, it is 20 to 90 minutes. As the heating, a known method, for example, a hot plate, a hot air circulation oven, an IR (infrared) oven, a belt furnace, or the like can be used.

Polycondensation of the polysiloxane in a liquid crystal aligning film advances in a baking process. However, in the present invention, it is not necessary to completely polycondense unless the effect of the present invention is impaired. However, it is preferable to bake at 10 degreeC or more high temperature at the heat processing temperature, such as sealing compound hardening required in a liquid crystal cell manufacturing process.

Although the thickness of this cured film can be selected as needed, Preferably it is 5 nm or more, More preferably, since it is easy to acquire the reliability of a liquid crystal display element, it is preferable. When the thickness of the cured film is preferably 300 nm or less, more preferably 150 nm or less, the power consumption of the liquid crystal display element is not extremely increased, which is preferable.

<Liquid crystal display element>

The liquid crystal display element of this invention can manufacture and obtain a liquid crystal cell by a well-known method, after forming a liquid crystal aligning film in a board | substrate by the said method. As an example of liquid crystal cell manufacture, the method of fixing a pair of board | substrates with which the liquid crystal aligning film was formed, fixing it with a sealing agent between spacers, and injecting and sealing a liquid crystal is common. In that case, although the size of the spacer to be used is 1-30 micrometers, Preferably it is 2-10 micrometers.

The method for injecting the liquid crystal is not particularly limited, and the vacuum method for injecting the liquid crystal after the inside of the manufactured liquid crystal cell is reduced in pressure, the dropping method for sealing after dropping the liquid crystal, and the like.

In the liquid crystal display element of a PSA system, the liquid crystal which added the photopolymerizable compound preferably a small amount (typically 0.2-1 weight%) as a liquid crystal used can be used. Polymerizable compound by irradiating ultraviolet (UV) light having a wavelength of 230 to 400 nm, more preferably 300 to 380 nm in a state where a voltage is applied between electrodes of both substrates of the liquid crystal cell into which the liquid crystal is introduced. By superposing | polymerizing in this place and bridge | crosslinking, the response speed of a liquid crystal display becomes quick. The voltage to be applied here is 5 to 30 Vp-p, but preferably 5 to 20 Vp-p. Although the amount of UV irradiation to irradiate is 1-60 J, Preferably it is 40 J or less, and the one with little UV irradiation amount can suppress the reliability fall caused by the destruction of the member which comprises a liquid crystal display, and can also reduce UV irradiation time. As the tact on manufacture becomes high, it is preferable. The liquid crystal aligning agent of this invention is used also in the liquid crystal display element in which a polymeric compound is not added.

The substrate used for the liquid crystal display element is not particularly limited as far as it is a substrate having high transparency. Normally, it is a substrate on which a transparent electrode for driving liquid crystal is formed. Specific examples are the same as those of the substrate described in [Liquid Crystal Alignment Film]. In the case of the PSA system liquid crystal cell, an electrode pattern or a projection pattern such as standard PVA or MVA can also be used for the substrate. However, in the liquid crystal display of the PSA system, even in the structure which forms the line / slit electrode pattern of 1-10 micrometers in one side board | substrate, and does not form the slit pattern and protrusion pattern in the opposing board | substrate, it can operate, and the liquid crystal of this structure The display at the time of manufacturing can be simplified by a display, and high transmittance | permeability can be obtained.

In a high-performance device such as a TFT-type device, a device such as a transistor is formed between an electrode for liquid crystal driving and a substrate.

In the case of a transmissive liquid crystal element, it is common to use a substrate as described above. However, in a reflective liquid crystal display element, it is possible to use an opaque substrate such as a silicon wafer as long as only one substrate. At this time, a material such as aluminum that reflects light may be used for the electrode formed on the substrate.

Example

Hereinafter, although an Example of this invention demonstrates more concretely, it is not limited to these.

The abbreviation in the compound used by the present Example is as follows.

TEOS: Tetraethoxysilane

C18: octadecyl triethoxysilane

VTES ： Vinyl Triethoxysilane

ARMS ： allyltrimethoxysilane

OTMS: Octenyltrimethoxysilane

STMS: styryl trimethoxysilane

HG: 2-methyl-2,4-pentanediol (alias name: hexylene glycol)

BCS: 2-butoxyethanol

UPS: 3-ureidopropylethoxysilane

&Lt; Synthesis Example 1 &

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

For the resulting polysiloxane solution was 10.0 g, a mixture of 20.0 g BCS, in terms of SiO ₂ concentration of 4% by weight to obtain a liquid crystal aligning agent (K1).

&Lt; Synthesis Example 2 &

In a 200 mL four-necked reaction flask with a thermometer and a reflux tube, 1.7 g of HG 21.6 g, BCS 7.2 g, TEOS 27.5 g, C18 and 13.9 g of OTMS were mixed to prepare a solution of an alkoxysilane monomer. The solution which mixed 0.9 g of oxalic acid as HG 10.8g, BCS 3.6g, water 10.8g, and a catalyst previously was dripped at this solution over 30 minutes under room temperature. After stirring this solution for 30 minutes and refluxing for 1 hour, the liquid mixture of 1.2 g of UPS solutions 92 mass% methanol solution, 0.6 g of HG, and 0.2 g of BCS was added previously. The mixture was further refluxed for 30 minutes and allowed to stand to obtain a polysiloxane solution having a SiO ₂ equivalent concentration of 12% by weight.

For the resulting polysiloxane solution was 10.0 g, a mixture of 20.0 g BCS, in terms of SiO ₂ concentration of 4% by weight to obtain a liquid crystal aligning agent (K2).

&Lt; Synthesis Example 3 &

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

For the resulting polysiloxane solution was 10.0 g, a mixture of 20.0 g BCS, in terms of SiO ₂ concentration of 4% by weight to obtain a liquid crystal aligning agent (K3).

<Comparative Synthesis Example 1>

In a 200 mL four-necked reaction flask equipped with a thermometer and a reflux tube, 1.7 g of HG 23.3 g, BCS 7.7 g, TEOS 40.8 g, and C18 were mixed to prepare a solution of an alkoxysilane monomer. The solution which mixed oxalic acid 0.2g as HG 11.6g, BCS 3.9g, water 10.8g, and a catalyst previously was dripped at this solution over 30 minutes under room temperature. Stirring the solution for 30 minutes and then refluxed for 1 hour after the bangraeng SiO ₂ in terms of solid content of the polysiloxane solution to give a 12% by weight.

For the resulting polysiloxane solution was 10.0 g, a mixture of 20.0 g BCS, in terms of SiO ₂ concentration of 4% by weight to obtain a liquid crystal aligning agent (L1).

<Comparative Synthesis Example 2>

In a 200 mL four-necked reaction flask with a thermometer and a reflux tube, 1.7 g of HG 21.8 g, BCS 7.3 g, 27.5 g of C18 and C18 and 13.5 g of VTES were mixed to prepare a solution of an alkoxysilane monomer. The solution which mixed 0.9 g of oxalic acid as HG 10.9g, BCS 3.6g, water 10.8g, and a catalyst previously was dripped at this solution over 30 minutes under room temperature. After stirring this solution for 30 minutes and refluxing for 1 hour, the liquid mixture of 1.2 g of UPS solutions 92 mass% methanol solution, 0.6 g of HG, and 0.2 g of BCS was added previously. The mixture was further refluxed for 30 minutes and allowed to stand to obtain a polysiloxane solution having a SiO ₂ equivalent concentration of 12% by weight.

For the resulting polysiloxane solution was 10.0 g, a mixture of 20.0 g BCS, in terms of SiO ₂ concentration of 4% by weight to obtain a liquid crystal aligning agent (L2).

&Lt; Example 1 &gt;

The liquid-crystal aligning agent [K1] obtained by the synthesis example 1 was spin-coated to the ITO surface of the ITO electrode substrate in which the pixel size is 100 micrometers x 300 micrometers, and the ITO electrode pattern whose line / space is 5 micrometers, respectively. After drying for 5 minutes on an 80 degreeC hotplate, baking was performed for 30 minutes in 180 degreeC hot-air circulation type oven, and the liquid crystal aligning film with a film thickness of 100 nm was formed.

After spin-coating the liquid-crystal aligning agent [K1] obtained by the synthesis example 1 to the ITO surface in which the electrode pattern is not formed, and drying for 5 minutes on an 80 degreeC hotplate, baking for 30 minutes in 180 degreeC hot-air circulation type oven. It carried out and formed the liquid crystal aligning film of 100 nm in film thickness. These two board | substrates were prepared, after spread | dispersing a 6 micrometers bead spacer on the liquid crystal aligning film surface of one board | substrate, the sealing compound was printed from on. After attaching the other board | substrate with the liquid crystal aligning film surface inside, the sealing compound was hardened and the empty cell was produced. The liquid crystal cell which injected the said liquid crystal into liquid crystal MLC-6608 (Merck & Co., Ltd. brand name) by the vacuum pressure injection method was manufactured.

The response speed characteristic of these liquid crystal cells was measured by the method mentioned later. Then, UV (wavelength: 280-330 nm) 20J was irradiated from the outer side of this liquid crystal cell in the state which applied the voltage of 20 Vp-p to this liquid crystal cell. Then, the response speed characteristic was measured again and the response speed in UV irradiation back and front was compared. The results are shown in Table 1.

<Example 2>

Except having changed the liquid-crystal aligning agent [K1] into the liquid-crystal aligning agent [K2] obtained by the synthesis example 2, it carried out similarly to Example 1, and produced the liquid crystal cell, and measured the response speed. The results are shown in Table 1.

<Example 3>

Except having changed the liquid-crystal aligning agent [K1] into the liquid-crystal aligning agent [K3] obtained by the synthesis example 3, it carried out similarly to Example 4, and produced the liquid crystal cell, and measured the response speed. The results are shown in Table 1.

&Lt; Comparative Example 1 &

Except having changed the liquid-crystal aligning agent [K1] into the liquid-crystal aligning agent [L1] obtained by the comparative synthesis example 1, the liquid crystal cell was produced like Example 1-Example 3, and the response speed was measured. The results are shown in Table 1.

<Comparative Example 2>

Except having changed the liquid-crystal aligning agent [K1] into the liquid-crystal aligning agent [L2] obtained by the comparative synthesis example 2, the liquid crystal cell was produced like Example 1-Example 3, and the response speed was measured. The results are shown in Table 1.

Response speed characteristic

The time change of the brightness | luminance of a liquid crystal panel when the rectangular wave of voltage +/- 4V and frequency 1 Hz was applied to the liquid crystal cell to which no voltage was applied was introduce | transduced into an oscilloscope. When the voltage is not applied, a luminance of 0% and a voltage of ± 4 V are applied, and the value of saturated luminance is set to 100%, and the time at which the luminance changes from 10% to 90% is increased. Unit: milliseconds).

Liquid crystal aligning agent
Response rate characteristic (ms) Before UV irradiation After UV irradiation Example 1 K1 800 510 Example 2 K2 800 550 Example 3 K3 800 330 Comparative Example 1 L1 800 800 Comparative Example 2 L2 800 800

As can be seen from Table 1, in the liquid crystal cell of the example, even when a liquid crystal without the polymerizable compound was used, the response speed improved after UV irradiation. On the other hand, in the comparative example, the response speed did not improve before and after UV irradiation.

Industrial availability

Even in the case of the PSA system in which the polymerizable compound is added to the liquid crystal, even when a liquid crystal without the polymerizable compound is used, the liquid crystal aligning agent of the present invention can improve the response speed and obtain a good alignment state. The liquid crystal display element manufactured using the liquid crystal aligning agent of is useful as a TFT liquid crystal display element, a TN liquid crystal display element, VA liquid crystal display element, etc.

Claims (12)

Polysiloxane obtained by polycondensing the alkoxysilane represented by Formula (1) and the alkoxysilane represented by Formula (2) is contained, The liquid crystal aligning agent characterized by the above-mentioned.
R ¹ Si (OR ² ) ₃ (1)
(R ¹ is a hydrocarbon group having 8 to 30 carbon atoms which may be substituted with a fluorine atom, and R ² represents an alkyl group having 1 to 5 carbon atoms.)
[Formula 1]

(R ³ is a hydrocarbon group having 1 to 18 carbon atoms, and R ⁴ represents an alkyl group having 1 to 5 carbon atoms.) The method of claim 1,
The liquid crystal aligning agent whose R <^3> of the said Formula (2) is an alkylene group. The method of claim 1,
R <^3> of the said Formula (2) is a liquid crystal aligning agent represented by following formula (3) (m and n are integers of 0-6, respectively).
(2)

The method according to any one of claims 1 to 3,
The liquid crystal aligning agent whose polysiloxane is polysiloxane obtained by polycondensing the alkoxysilane containing the alkoxysilane represented by following formula (4) further.
(R ⁵ ) _n Si (OR ⁶ ) _4-n (4)
(R ⁵ is a hydrocarbon group having 1 to 6 carbon atoms which may be substituted with a hydrogen atom, a hetero atom, a halogen atom, an amino group, a glycidoxy group, a mercapto group, an isocyanate group or a ureido group, and R ⁶ is An alkyl group having 1 to 5 carbon atoms, n represents an integer of 0 to 3) The method of claim 4, wherein
The alkoxysilane represented by the said Formula (4) is a tetraalkoxy silane whose n in Formula (4) is 0, The liquid crystal aligning agent. 6. The method according to any one of claims 1 to 5,
Alkoxy which the said polysiloxane contains 0.1-30 mol% of the alkoxysilane represented by Formula (1) in all alkoxysilanes, and contains 3-70 mol% in all the alkoxysilanes shown by the said Formula (2). The liquid crystal aligning agent obtained by polycondensing a silane. 7. The method according to any one of claims 4 to 6,
The liquid crystal aligning agent obtained by polycondensing the alkoxysilane which the said polysiloxane contains 10-96.9 mol% in all the alkoxysilanes of the alkoxysilane represented by Formula (4). 7. The method according to any one of claims 1 to 6,
When the content of the polysiloxane, the liquid crystal alignment to be contained 0.5 to 15% by weight in terms of SiO ₂ concentration. The liquid crystal aligning film obtained by apply | coating the liquid crystal aligning agent in any one of Claims 1-8 to a board | substrate, drying, and baking. The liquid crystal display element which has a liquid crystal aligning film of Claim 9. The liquid crystal display element which apply | coated the liquid crystal aligning agent in any one of Claims 1-8, and irradiated UV in the state which applied the voltage to the liquid crystal cell in which the liquid crystal was clamped by the baked two board | substrates. The manufacturing method of the liquid crystal display element which apply | coats the liquid crystal aligning agent in any one of Claims 1-8, clamps a liquid crystal with two baked board | substrates, and irradiates UV in the state which applied the voltage.