JP5605359B2 - Silicon-based liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Description

The present invention relates to a liquid crystal display device and a manufacturing method thereof having a liquid crystal alignment film obtained liquid crystal aligning agent do we containing polysiloxane obtained by polycondensation of an alkoxysilane.

  In recent years, among liquid crystal display element display methods, vertical (VA) liquid crystal display elements are widely used for large-screen liquid crystal televisions and high-definition mobile applications (display units of digital cameras and mobile phones). . In the VA method, the MVA method (Multi Vertical Alignment) in which a protrusion for controlling the direction in which the liquid crystal falls is formed on the TFT substrate or the color filter substrate, and the direction in which the liquid crystal falls by an electric field by forming a slit in the ITO electrode of the substrate A PVA (Paterned Vertical Alignment) system to be controlled is known.

  As another VA alignment method, there is a PSA (Polymer susutained Alignment) method. Among VA systems, the PSA system is a technology that has attracted attention in recent years. In this method, a photopolymerizable compound is added to the liquid crystal, and after the liquid crystal panel is produced, an electric field is applied to irradiate the liquid crystal panel with UV in a state where the liquid crystal is tilted. As a result, the polymerizable compound is photopolymerized to fix the alignment direction of the liquid crystal, causing a pretilt and improving the response speed. In the VA method, a slit is formed in one electrode constituting the liquid crystal panel, and a structure in which a projection such as MVA or a slit such as PVA is not provided in the opposite electrode pattern is operable. It is characterized by simplification and excellent panel transmittance. (See Patent Document 1.)

  On the other hand, inorganic liquid crystal alignment film materials are also known along with conventionally used organic liquid crystal alignment film materials such as polyimide. For example, a liquid crystal aligning agent composition containing a reaction product of tetraalkoxysilane, trialkoxysilane, alcohol, and oxalic acid is used as a material for a coating-type inorganic alignment film on an electrode substrate of a liquid crystal display element. It is reported that a liquid crystal alignment film having excellent vertical alignment properties, heat resistance and uniformity is formed. (See Patent Document 2.)

  In addition, by using a liquid crystal aligning agent composition containing a reaction product of tetraalkoxysilane, specific trialkoxysilane and water and a specific glycol ether solvent, display defects are prevented and even after long-time driving. It has been reported to form a liquid crystal alignment film with good afterimage characteristics, without reducing the ability to align liquid crystals, and with little reduction in voltage holding ratio against light and heat. (See Patent Document 3)

JP 2004-302061 A JP 09-281502 A JP 2005-250244 A

  Conventionally, in a PSA type liquid crystal display element, there is a problem that the polymerizable compound added to the liquid crystal has low solubility, and when the addition amount is increased, it is precipitated at a low temperature. On the other hand, when the addition amount of the polymerizable compound is reduced, a good alignment state cannot be obtained. Moreover, 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.

The object of the present invention is to improve the response speed in a PSA type liquid crystal display element even when the amount of the polymerizable compound is small, or even when using a liquid crystal without adding a polymerizable compound, and a good alignment state. it is to provide a liquid crystal display device and a manufacturing method thereof is possible to obtain.

The gist of the present invention is as follows.
[1] contains an alkoxysilane represented by the alkoxysilane and the following formula represented by the following formula (1) (2), in the total alkoxysilane, an alkoxysilane represented by the formula (2) is 10 to 60 mol Applying a liquid crystal aligning agent containing polysiloxane obtained by polycondensation of alkoxysilane contained in an amount of UV, and irradiating the liquid crystal cell sandwiched with two baked substrates with voltage applied. A liquid crystal display element characterized by comprising:
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.)
R ³ Si (OR ⁴ ) ₃ (2)
(R ³ is an alkyl group substituted with an acryl group or a methacryl group, and R ⁴ has 1 to 5 carbon atoms.
Represents an alkyl group. )

[2] The liquid crystal display element according to the above [1], wherein the polysiloxane is obtained by polycondensation of an alkoxysilane containing an alkoxysilane represented by the following formula (3).
(R ⁵ ) _n Si (OR ⁶ ) _4-n (3)
(R ⁵ is a hydrogen atom or a hydrocarbon group having 1 to 16 carbon atoms which may be substituted with a hetero atom, a halogen atom, an amino group, a glycidoxy group, a mercapto group, an isocyanate group or a ureido group; R ⁶ is an alkyl group having 1 to 5 carbon atoms, and n represents an integer of 0 to 3.
[3] The alkoxysilane represented by the formula (1), wherein R ¹ in the formula (1) is a hydrocarbon group having 8 to 22 carbon atoms, and R ² is methyl or ethyl [1] Or the liquid crystal display element as described in [2].

[4] The alkoxysilane represented by the formula (2) is 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxy. The liquid crystal display element according to any one of the above [1] to [3], which is at least one selected from the group consisting of silanes.
[5] The liquid crystal display element according to any one of the above [2] to [4], wherein R ^{5 of the} alkoxysilane represented by the formula (3) is a hydrocarbon group having 1 to 6 carbon atoms.
[6] The liquid crystal display element according to any one of [2] to [5], wherein the alkoxysilane represented by the formula (3) is a tetraalkoxysilane in which n in the formula (3) is 0.
[7] The alkoxysilane represented by the formula (1) is contained in an amount of 0.1 to 30 mol% in all alkoxysilanes, and the alkoxysilane represented by the formula (2) is contained in all alkoxysilanes. The liquid crystal display element according to any one of the above [1] to [4], which is contained in an amount of 3 to 60 mol%.

[8] The liquid crystal display element according to any one of the above [2] to [7], wherein the alkoxysilane represented by the formula (3) is contained in 10 to 96.9 mol% in all alkoxysilanes.
[9] The liquid crystal display element according to any one of [1] to [8], wherein the polysiloxane content is 0.5 to 15% by mass in terms of SiO ₂ concentration.
[10] An alkoxysilane represented by the following formula (1) and an alkoxysilane represented by the following formula (2) are included, and 10-60 mol of the alkoxysilane represented by the above formula (2) in all alkoxysilanes. % alkoxysilane included applying a liquid crystal aligning agent containing a polycondensation obtained polysiloxanes, liquid crystal sandwiched by the two substrates and fired, and characterized by irradiating UV while applying a voltage A method for manufacturing a liquid crystal display element.
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.)
R ³ Si (OR ⁴ ) ₃ (2)
(R ³ represents an alkyl group substituted with an acryl group or a methacryl group, and R ⁴ represents an alkyl group having 1 to 5 carbon atoms.)

According to the onset bright, in the liquid crystal display device having a PSA mode, even when the amount of the polymerizable compound added to the liquid crystal is small, and even when using a liquid crystal without addition polymerizable compound, the response speed the liquid crystal display device having improved Ru can der to obtain a good alignment state liquid crystal alignment film can be obtained.

The present invention is described in detail below.
Liquid crystal aligning agent of the present invention, viewed contains the alkoxysilane represented by alkoxysilanes and wherein the formula (1) (2), the alkoxysilane of the formula (2) from 10 to 60 mol% It is a liquid crystal aligning agent containing polysiloxane obtained by polycondensation of contained alkoxysilane.
R ¹ Si (OR ² ) ₃ (1)
(R ¹ is a hydrocarbon group having 8 to 30 carbon atoms that may be substituted with a fluorine atom, and R ² represents an alkyl group having 1 to 5 carbon atoms.) “May be substituted” means “substituted or unsubstituted”.
R ³ Si (OR ⁴ ) ₃ (2)
(R ³ represents an alkyl group substituted with an acryl group or a methacryl group, and R ⁴ represents an alkyl group having 1 to 5 carbon atoms.)

[Polysiloxane]
R ¹ (hereinafter also referred to as a specific organic group) of the alkoxysilane represented by the formula (1) has 8 to 30 carbon atoms which may be substituted with fluorine, preferably 8 to 22 and particularly preferably 10 carbon atoms. The hydrocarbon group is not particularly limited as long as it has an effect of vertically aligning the liquid crystal. Examples thereof include an alkyl group, a fluoroalkyl group, an alkenyl group, a phenethyl group, a styrylalkyl group, a naphthyl group, and a fluorophenylalkyl group. Among these, alkoxysilanes in which R ¹ is an alkyl group or a fluoroalkyl group are preferable because they are relatively inexpensive and easily available as commercial products. In particular, alkoxysilane in which R ¹ is an alkyl group is preferable. The polysiloxane used in the present invention may have a plurality of these 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.
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, hexadecyltriethoxysilane, heptadecyltrimethoxysilane, Heptadecyltriethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, nonadecyltrimethoxysilane, nonadecyltriethoxysilane, undecyltriethoxysilane, undecyltrimethoxysilane, 21-docosenyltriethoxysilane, trideca Fluorooctyltrimethoxysilane, tridecafluorooctyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, heptadecaful B decyl triethoxysilane, iso-octyltriethoxysilane, phenethyl triethoxysilane, pentafluoro-phenylpropyl trimethoxysilane, (1-naphthyl) triethoxysilane, and (1-naphthyl) trimethoxysilane. Among them, octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, heptadecyltrimethoxysilane Heptadecyltriethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, nonadecyltrimethoxysilane, nonadecyltriethoxysilane, undecyltriethoxysilane, or undecyltrimethoxysilane is preferred.

  The alkoxysilane 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 in all alkoxysilanes used for obtaining polysiloxane. More preferably, it is 0.5 mol% or more. More preferably, it is 1 mol% or more. Further, in order to obtain sufficient curing characteristics of the liquid crystal alignment film to be formed, 30 mol% or less is preferable. More preferably, it is 22 mol% or less.

On the other hand, equation (2) alkoxysilane R ³ represented by ^{(hereinafter,} also referred to as a second specific organic groups) R ³ is an alkyl group substituted with an acrylic group or methacrylic group. The number of substituted hydrogen atoms is one or more, preferably one. 1-30 are preferable and, as for the carbon atom number of an alkyl group, More preferably, it is 1-10. More preferably, it is 1-5. R ⁴ of the alkoxysilane represented by the formula (2) is the same as the definition of R ^{2 in} the above formula (1), and a preferable group of R ⁴ is the same as that of R ² .

  Although the specific example of the alkoxysilane represented by Formula (2) is given, it is not limited to these. For example, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, methacryloxymethyltrimethoxysilane, methacryloxymethyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxy Examples include silane, acryloxyethyltrimethoxysilane, acryloxyethyltriethoxysilane, and the like.

In order to improve the response speed of the PSA type liquid crystal display element even when the amount of the PSA type polymerizable compound is small, the alkoxysilane represented by the formula (2) having the second specific organic group obtains polysiloxane. Te entire alkoxysilanes in odor used for, is 1 0 mol% or more, and in order to sufficiently cure the liquid crystal alignment film to be formed is Ru der 60 mol% or less.
In the present invention, the alkoxysilane represented by the formula (1) is preferably contained in an amount of 0.1 to 30 mol%, particularly preferably 2 to 20 mol%, in all alkoxysilanes used.

In this invention, the alkoxysilane represented by following formula (3) other than the alkoxysilane represented by Formula (1) and Formula (2) can be used. Since the alkoxysilane represented by the formula (3) can impart various characteristics to the polysiloxane, one or more kinds can be selected and used according to the required characteristics.
(R ⁵ ) _n Si (OR ⁶ ) _4-n (3)
In the formula, R ⁵ is a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms which may be substituted with a hetero atom, a halogen atom, an amino group, a glycidoxy group, a mercapto group, an isocyanate group or a ureido group. R ⁶ is an alkyl group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, and n represents an integer of 0 to 3, preferably 0 to 2.

R ⁵ of the alkoxysilane represented by the formula (3) 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 aliphatic hydrocarbons; ring structures such as aliphatic rings, aromatic rings and heterocycles; unsaturated bonds; and heteroatoms such as oxygen atoms, nitrogen atoms and sulfur atoms. It is a hydrocarbon having 1 to 16, more preferably 1 to 12, and particularly preferably 1 to 6 carbon atoms which may be included and may have a branched structure. This hydrocarbon may be substituted with a halogen atom, amino group, glycidoxy group, mercapto group, isocyanate group, ureido group or the like.
Although the specific example of the alkoxysilane represented by such Formula (3) is given, it is not limited to this.
In the alkoxysilane of the formula (3), specific examples of the alkoxysilane when R ⁵ is a hydrogen atom include trimethoxysilane, triethoxysilane, tripropoxysilane, tributoxysilane and the like.

Further, in the alkoxysilane of the formula (3), specific examples of the alkoxysilane when R ⁵ is a third organic group include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, and ethyltriethoxysilane. , Propyltrimethoxysilane, propyltriethoxysilane, methyltripropoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2 (aminoethyl) 3-aminopropyltriethoxysilane, N-2 (Aminoethyl) 3-aminopropyltrimethoxysilane, 3- (2-aminoethylaminopropyl) trimethoxysilane, 3- (2-aminoethylaminopropyl) triethoxysilane, 2-aminoethylaminomethyltrimethoxysilane, 2- (2-A Minoethylthioethyl) triethoxysilane, 3-mercaptopropyltriethoxysilane, mercaptomethyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, trifluoropropyltrimethoxysilane, chloropropyltriethoxysilane, bromopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, diethyldiethoxysilane, diethyldimethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyldimethylethoxy Silane, trimethylethoxysilane, trimethylmethoxysilane, γ-ureidopropyltriethoxysilane, γ-ureidopropylene Trimethoxysilane and γ- ureidopropyl tripropoxysilane, and the like.

The polysiloxane used in the present invention is a kind of the alkoxysilane represented by the above formula (3) as long as the effect of the present invention is not impaired for the purpose of improving the adhesion with the substrate and the affinity with the liquid crystal molecules. Or you may have multiple types.
In the alkoxysilane represented by the formula (3), the alkoxysilane in which n is 0 is tetraalkoxysilane. Tetraalkoxysilane is preferable for obtaining the polysiloxane of the present invention because it easily condenses with the alkoxysilane represented by the formulas (1) and (2).
As the alkoxysilane in which n is 0 in the formula (3), tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane or tetrabutoxysilane is more preferable, and tetramethoxysilane or tetraethoxysilane is particularly preferable.
When using together the alkoxysilane represented by Formula (3), the usage-amount of the alkoxysilane represented by Formula (3) is 10-96.9 mol% in all the alkoxysilanes used in order to obtain polysiloxane. It is preferable that More preferably, it is 35-99.8 mol%.

[Production method of polysiloxane]
The method for obtaining the polysiloxane used in the present invention is not particularly limited. In the present invention, it is obtained by condensing an alkoxysilane having the above-mentioned formulas (1) and (2) as essential components in an organic solvent. Usually, polysiloxane is obtained as a solution obtained by polycondensation of such alkoxysilanes and uniformly dissolved in an organic solvent.
Examples of the method for polycondensing the alkoxysilane include a method of hydrolyzing and condensing the alkoxysilane in a solvent such as alcohol or glycol. At that time, the hydrolysis / condensation reaction may be either partial hydrolysis or complete hydrolysis. In the case of complete hydrolysis, theoretically, it is sufficient to add 0.5 times mole of water of all alkoxy groups in the alkoxysilane, but it is usually preferable to add an excess amount of water more than 0.5 times mole.
The amount of water used in the above reaction can be appropriately selected as desired, but it is usually preferably 0.5 to 2.5 times mol of all alkoxy groups in alkoxysilane.

In the present invention, usually, for the purpose of accelerating hydrolysis / condensation reaction, acids such as hydrochloric acid, sulfuric acid, nitric acid, acetic acid, formic acid, succinic acid, maleic acid, fumaric acid; ammonia, methylamine, ethylamine, ethanolamine It is preferable to use a catalyst such as alkali such as triethylamine; metal salt such as hydrochloric acid, sulfuric acid and nitric acid. In addition, the hydrolysis / condensation reaction can be further promoted by heating the solution in which the alkoxysilane is dissolved. At that time, the heating temperature and the heating time can be appropriately selected as desired. For example, heating and stirring at 50 ° C. for 24 hours, heating and stirring for 1 hour under reflux, and the like can be mentioned.
As another method, for example, a method of heating and polycondensing a mixture of alkoxysilane, a solvent and oxalic acid can be mentioned. Specifically, after adding oxalic acid to alcohol in advance to obtain an alcohol solution of oxalic acid, 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 alkoxysilane has. Heating in this method can be performed at a liquid temperature of 50 to 180 ° C. Preferably, it is a method of heating for several tens of minutes to several tens of hours under reflux so that evaporation or volatilization of the liquid does not occur.

When using multiple types of alkoxysilanes when obtaining polysiloxane, the alkoxysilanes may be mixed in advance, or multiple types of alkoxysilanes may be mixed in sequence.
The solvent used for polycondensation of alkoxysilane (hereinafter also referred to as polymerization solvent) is not particularly limited as long as it can dissolve alkoxysilane. Moreover, even when alkoxysilane does not melt | dissolve, what is melt | dissolved should just melt | dissolve with the progress of the polycondensation reaction of alkoxysilane. In general, since an alcohol is generated by a polycondensation reaction of alkoxysilane, an alcohol, a glycol, a glycol ether, or an organic solvent having good compatibility with the 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-pentanediol, 2,4-pentanediol, 2,3-pentanediol, 1,6-hexanediol and the like glycols: 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 monobutyl ether, diethylene 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, 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 above polymerization solvents may be mixed and used.
The polysiloxane polymerization solution (hereinafter also referred to as polymerization solution) obtained by the above method is a concentration obtained by converting silicon atoms of all alkoxysilanes charged as raw materials into SiO ₂ (hereinafter referred to as SiO ₂ conversion concentration). ) Is preferably 20% by mass or less, and more preferably 5 to 15% by mass. By selecting an arbitrary concentration within this concentration range, gel formation can be suppressed and a homogeneous solution can be obtained.

[Polysiloxane solution]
In the present invention, the polymerization solution obtained by the above method may be used as a polysiloxane solution as it is, or if necessary, the solution obtained by the above method may be concentrated or diluted by adding a solvent. Or may be substituted with another solvent to form a polysiloxane solution.
In that 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 additive solvent is not particularly limited as long as the polysiloxane is uniformly dissolved, and one kind or plural kinds can be arbitrarily selected and used.

Specific examples of such an additive solvent include, in addition to the solvents mentioned as examples of the polymerization solvent described above, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; esters such as methyl acetate, ethyl acetate, and ethyl lactate. Can be mentioned.
These solvents can improve the applicability when the liquid crystal aligning agent is applied onto the substrate by adjusting the viscosity of the liquid crystal aligning agent, or by spin coating, flexographic printing, ink jetting or the like.

[Other ingredients]
In the liquid crystal aligning agent of the present invention, other components other than polysiloxane, such as inorganic fine particles, metalloxane oligomers, metalloxane polymers, leveling agents, and further surfactants, etc., as long as the effects of the present invention are not impaired. May be included.
As the inorganic fine particles, fine particles such as silica fine particles, alumina fine particles, titania fine particles, and magnesium fluoride fine particles are preferable, and those in the state of a colloidal solution are particularly preferable. This colloidal solution may be a dispersion of inorganic fine particles in a dispersion medium, or a commercially available colloidal solution. In the present invention, the inclusion of inorganic fine particles makes it possible to impart the surface shape of the formed cured film and other functions. The inorganic fine particles preferably have an average particle size of 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 transparency of the cured film formed using the prepared coating liquid may be lowered.
Examples of the dispersion medium for the inorganic fine particles include water and organic solvents. As a colloidal solution, it is preferable that pH or pKa is adjusted to 1-10 from the viewpoint of the stability of the coating liquid for forming a film. More preferably, it is 2-7.

Examples of the organic solvent used for 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; esters such as ethyl acetate, butyl acetate and γ-butyrolactone; Examples include ethers such as tetrahydrofuran and 1,4-dioxane. Of these, alcohols or ketones are preferred. These organic solvents can be used alone or in admixture of two or more as a dispersion medium.
As the metalloxane oligomer and metalloxane polymer, single or composite oxide precursors such as silicon, titanium, aluminum, tantalum, antimony, bismuth, tin, indium, and zinc are used. The metalloxane oligomer or metalloxane polymer may be a commercially available product or may be obtained from a monomer such as a metal alkoxide, nitrate, hydrochloride, or carboxylate by a conventional method such as hydrolysis.

Specific examples of commercially available metalloxane oligomers and metalloxane polymers include siloxane oligomers or siloxanes such as methyl silicate 51, methyl silicate 53A, ethyl silicate 40, ethyl silicate 48, EMS-485, and SS-101 manufactured by Colcoat. Examples thereof include titanoxane oligomers such as a polymer and titanium-n-butoxide tetramer manufactured by Kanto Chemical Co., Inc. You may use these individually or in mixture of 2 or more types.
Moreover, a leveling agent, surfactant, etc. can use a well-known thing, and since a commercial item is easy to acquire especially, it is preferable.
Moreover, the method of mixing the above-mentioned other components with polysiloxane may be simultaneous with or after polysiloxane, and is not particularly limited.

[Liquid crystal aligning agent]
The liquid crystal aligning agent of this invention melt | dissolves the polysiloxane mentioned above in a solvent, and contains other components by melt | dissolving or disperse | distributing as needed. As the solvent, a solvent selected from the group consisting of the above-mentioned polysiloxane polymerization solvent and additive solvent is used. The content of polysiloxane in the liquid crystal aligning agent is preferably 0.5 to 15% by mass, more preferably 1 to 6% by mass in terms of SiO ₂ equivalent concentration. Be in the range of such terms of SiO ₂ concentration, easy to obtain a desired film thickness by a single coating, easy pot life sufficient solution is obtained.

The method for preparing the liquid crystal aligning agent of the present invention is not particularly limited. The polysiloxane used in the present invention may be in a state where other components added as necessary are uniformly mixed. Since polysiloxane is usually polycondensed in a solvent, it is convenient to use the polysiloxane solution as it is or to add other components to the polysiloxane solution as necessary. Furthermore, the most convenient method is to use the polysiloxane polymerization solution as it is.
Moreover, when adjusting content of 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 film]
The liquid crystal aligning film of this invention is obtained using the said liquid crystal aligning agent. For example, after applying the liquid crystal aligning agent of this invention to a board | substrate, the cured film obtained by drying and baking can also be used as a liquid crystal aligning film as it is. In addition, the cured film is rubbed, irradiated with polarized light or light of a specific wavelength, or treated with an ion beam, or a voltage is applied to the liquid crystal display element after filling the liquid crystal as a PSA alignment film It is also possible to irradiate with UV. In particular, it is useful to use as an alignment film for PSA.
The substrate on which the liquid crystal aligning agent is applied is not particularly limited as long as it is a highly transparent substrate, but a substrate in which a transparent electrode for driving liquid crystal is formed on the substrate is preferable.

Specific examples include glass plate, polycarbonate, poly (meth) acrylate, polyethersulfone, polyarylate, polyurethane, polysulfone, polyether, polyetherketone, trimethylpentene, polyolefin, polyethylene terephthalate, (meth) acrylonitrile, tri Examples thereof include a substrate in which a transparent electrode is formed on a plastic plate such as acetyl cellulose, diacetyl cellulose, and acetate butyrate cellulose.
Examples of the method for applying the liquid crystal aligning agent include spin coating, printing, ink jet, spraying, roll coating, and the like.In terms of productivity, the transfer printing method is widely used industrially. The present invention is also preferably used.

The drying process after applying the liquid crystal aligning agent is not necessarily required, but if the time from application to baking is not constant for each substrate, or if baking is not performed immediately after application, a drying process is included. Is preferred. The drying is not particularly limited as long as the solvent is removed to such an extent that the shape of the coating film is not deformed by transporting the substrate or the like. For example, a method of drying on a hot plate at a temperature of 40 ° C. to 150 ° C., preferably 60 ° C. to 100 ° C. for 0.5 to 30 minutes, preferably 1 to 5 minutes can be mentioned.
The coating film formed by applying the liquid crystal aligning agent by the above method can be baked to obtain a cured film. At that time, the firing temperature can be carried out at an arbitrary temperature of 100 ° C. to 350 ° C., preferably 140 ° C. to 300 ° C., more preferably 150 ° C. to 230 ° C., further preferably 160 ° C. to 220 ° C. It is. Firing can be performed at an arbitrary time of 5 minutes to 240 minutes. Preferably it is 10 to 90 minutes, More preferably, it is 20 to 90 minutes. For the heating, a generally known method such as a hot plate, a hot air circulation oven, an IR oven, a belt furnace or the like can be used.

The polysiloxane in the liquid crystal alignment film undergoes polycondensation in the firing step. However, in the present invention, it is not necessary to completely polycondense unless the effects of the present invention are impaired. However, firing is preferably performed at a temperature higher by 10 ° C. or more than the heat treatment temperature required for the liquid crystal cell production process, such as curing of the sealant.
The thickness of the cured film can be selected as necessary, but is preferably 5 nm or more, more preferably 10 nm or more, because the reliability of the liquid crystal display element can be easily obtained. Moreover, 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 does not become extremely large, which is suitable.

<Liquid crystal display element>
The liquid crystal display element of the present invention can be obtained by forming a liquid crystal alignment film on a substrate by the above method and then preparing a liquid crystal cell by a known method. As an example of manufacturing a liquid crystal cell, a method is generally employed in which a pair of substrates on which a liquid crystal alignment film is formed are fixed with a sealant with a spacer interposed therebetween, and liquid crystal is injected and sealed. In this case, the size of the spacer used is 1 to 30 μm, preferably 2 to 10 μm.
The method for injecting the liquid crystal is not particularly limited, and examples thereof include a vacuum method for injecting liquid crystal after the inside of the manufactured liquid crystal cell is decompressed, and a dropping method for sealing after dropping the liquid crystal.

  In a PSA liquid crystal display element, a liquid crystal to which a small amount (typically 0.2 to 1% by weight) of a photopolymerizable compound is used is used as the liquid crystal. By irradiating UV with a voltage applied between the electrodes on both sides of the liquid crystal cell in which this liquid crystal is introduced, the polymerizable compound is polymerized and crosslinked in situ, thereby increasing the response speed of the liquid crystal display. Become. Here, the applied voltage is 5 to 30 Vp-p, preferably 5 to 20 Vp-p. The UV irradiation amount to be irradiated is 1 to 60 J, preferably 40 J or less, and the smaller the UV irradiation amount, the lowering of reliability due to the destruction of the members constituting the liquid crystal display can be suppressed, and the UV irradiation time. It is preferable because the manufacturing tact can be increased by reducing.

  The substrate used for the liquid crystal display element is not particularly limited as long as it is a highly transparent substrate, but is usually a substrate in which a transparent electrode for driving liquid crystal is formed on the substrate. A specific example is the same as the substrate described in [Liquid crystal alignment film]. As a substrate that can be used in a PSA type liquid crystal cell, a standard electrode pattern such as PVA or MVA or a projection pattern can also be used. However, the PSA type liquid crystal display can operate even in a structure in which a line / slit electrode pattern of 1 to 10 μm is formed on one side substrate and no slit pattern or projection pattern is formed on the opposite substrate. The liquid crystal display can simplify the manufacturing process and obtain high transmittance.

As a high-performance element such as a TFT type element, an element in which an element such as a transistor is formed between an electrode for driving a liquid crystal and a substrate is used.
In the case of a transmissive liquid crystal display element, it is common to use a substrate as described above. However, in a reflective liquid crystal display element, if only one substrate is used, an opaque substrate such as a silicon wafer may be used. Is possible. At that time, a material such as aluminum that reflects light may be used for the electrode formed on the substrate.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention should not be construed as being limited thereto.
Abbreviations in the compounds used in the examples are as follows.
TEOS: tetraethoxysilane C18: octadecyltriethoxysilane ACPS: 3-acryloxypropyltrimethoxysilane HG: 2-methyl-2,4-pentanediol (also known as hexylene glycol)
BCS: 2-butoxyethanol UPS: 3-ureidopropyltriethoxysilane MPMS: 3-methacryloxypropyltrimethoxysilane

<Execution synthesis example 1>
In a 200 mL (liter) four-necked reaction flask equipped with a thermometer and reflux tube, 22.5 g HG, 7.5 g BCS, 28.3 g TEOS, 1.7 g C18, and 14.14 ACPS. 1 g was mixed to prepare an alkoxysilane monomer solution. To this solution, 11.2 g of HG, 3.7 g of BCS, 10.8 g of water, and 0.2 g of oxalic acid as a catalyst were added dropwise over 30 minutes at room temperature. The solution was stirred for 30 minutes and then refluxed for 1 hour, and then allowed to cool to obtain a polysiloxane solution having a SiO ₂ equivalent concentration of 12% by weight.
To the resulting polysiloxane solution 10.0 g, were mixed BCS20.0G, give in terms of SiO ₂ concentration of 4 wt% of the liquid crystal alignment agent (K1).

<Execution synthesis example 2>
In a 200 mL four-necked reaction flask equipped with a thermometer and a reflux tube, 21.1 g of HG, 7.0 g of BCS, 19.2 g of TEOS, 1.7 g of C18, and 23.4 g of ACPS were mixed. Then, a solution of the alkoxysilane monomer was prepared. To this solution, 10.5 g of HG, 3.5 g of BCS, 10.8 g of water, and 0.9 g of oxalic acid as a catalyst were added dropwise over 30 minutes at room temperature.
After stirring this solution for 30 minutes and refluxing for 1 hour, a mixed solution of 1.2 g of a methanol solution having a UPS content of 92% by mass, 0.5 g of HG and 0.2 g of BCS was added in advance. The mixture was further refluxed for 30 minutes and then allowed to cool to obtain a polysiloxane solution having a SiO ₂ equivalent concentration of 12% by weight.
To the resulting polysiloxane solution 10.0 g, were mixed BCS20.0G, give in terms of SiO ₂ concentration of 4 wt% of the liquid crystal alignment agent (K2).

<Execution synthesis example 3>
In a 200 mL four-necked reaction flask equipped with a thermometer and a reflux tube, 20.2 g of HG, 6.7 g of BCS, 27.9 g of TEOS, 1.7 g of C18, and 17.4 g of MPMS were mixed. Then, a solution of the alkoxysilane monomer was prepared. To this solution, 10.0 g of HG, 3.4 g of BCS, 10.8 g of water and 0.9 g of oxalic acid as a catalyst were added dropwise over 30 minutes at room temperature.
The solution was stirred for 30 minutes and then refluxed for 1 hour, and a mixed solution of 0.6 g of a methanol solution having a UPS content of 92% by mass, 0.3 g of HG and 0.1 g of BCS was added in advance. The mixture was further refluxed for 30 minutes and then allowed to cool to obtain a polysiloxane solution having a SiO ₂ equivalent concentration of 12% by weight.
To the resulting polysiloxane solution 10.0 g, were mixed BCS20.0G, to give SiO ₂ in terms of concentration of 4 wt% of the liquid crystal alignment agent (K3).

<Comparative Synthesis Example 1>
In a 200 mL four-necked reaction flask equipped with a thermometer and a reflux tube, 23.3 g of HG, 7.7 g of BCS, 40.8 g of TEOS, and 1.7 g of C18 are mixed to obtain a solution of an alkoxysilane monomer. Was prepared. To this solution, 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 were added dropwise over 30 minutes at room temperature.
The solution was stirred for 30 minutes and then refluxed for 1 hour, and then allowed to cool to obtain a polysiloxane solution having a solid content concentration of 12% by weight as SiO ₂ .
To the resulting polysiloxane solution 10.0 g, were mixed BCS20.0G, give in terms of SiO ₂ concentration of 4 wt% of the liquid crystal alignment agent (L1).

<Example 1>
The liquid crystal aligning agent [K1] obtained in Synthesis Example 1 was spin-coated on the ITO surface of an ITO electrode substrate on which an ITO electrode pattern having a pixel size of 100 μm × 300 μm and a line / space of 5 μm was formed. After drying on an 80 ° C. hot plate for 5 minutes, baking was performed in a hot air circulation oven at 180 ° C. for 30 minutes to form a liquid crystal alignment film having a thickness of 100 nm.
The liquid crystal aligning agent [K1] obtained in Synthesis Example 1 is spin-coated on the ITO surface on which no electrode pattern is formed, dried on an 80 ° C. hot plate for 5 minutes, and then heated in a 180 ° C. hot air circulation oven. Baking was performed for 30 minutes to form a liquid crystal alignment film having a thickness of 100 nm. These two substrates were prepared, and a 6 μm bead spacer was sprayed on the liquid crystal alignment film surface of one of the substrates, and a sealant was printed thereon. The other substrate was bonded with the liquid crystal alignment film surface inside, and then the sealing agent was cured to produce an empty cell. A liquid crystal in which 0.2% by weight of the polymerizable compound represented by the formula (S-1) was added to the liquid crystal MLC-6608 (trade name, manufactured by Merck & Co., Inc.) was prepared, and the liquid crystal was added to the empty cell by vacuum injection. A liquid crystal cell was injected.

  The response speed characteristics of these liquid crystal cells were measured by the method described later. Then, 20 J of UV was irradiated from the outside of the liquid crystal cell in a state where a voltage of 20 Vp-p was applied to the liquid crystal cell. Thereafter, the response speed characteristics were measured again, and the response speeds before and after UV irradiation (unit: ms) were compared. The results are shown in Table 1.

<Example 2>
The response speed was measured in the same manner as in Example 1 except that the polymerizable compound added to the liquid crystal MLC-6608 was changed to 0.05% by weight. The results are shown in Table 1.
<Example 3>
The response speed was measured in the same manner as in Example 1 except that the polymerizable compound added to the liquid crystal MLC-6608 was changed to 0.02% by weight. The results are shown in Table 1.

<Example 4>
The response speed was measured in the same manner as in Example 1 except that the polymerizable compound was not added to the liquid crystal MLC-6608. The results are shown in Table 1.
<Example 5>
A liquid crystal cell was produced in the same manner as in Example 4 except that the liquid crystal aligning agent [K1] was changed to the liquid crystal aligning agent [K2] obtained in Example Synthesis Example 2, and the response speed was measured. The results are shown in Table 1.
<Example 6>
A liquid crystal cell was prepared in the same manner as in Example 4 except that the liquid crystal alignment treatment agent [K1] was changed to the liquid crystal alignment treatment agent [K3] obtained in Example Synthesis Example 3, and the response speed was measured. The results are shown in Table 1.

<Comparative Examples 1 to 4>
A liquid crystal cell was prepared in the same manner as in Examples 1 to 4 except that the liquid crystal alignment treatment agent [K1] was changed to the liquid crystal alignment treatment agent [L1] obtained in Comparative Synthesis Example 1, and the response speed was measured. did. The results are shown in Table 1.

[Response speed characteristics]
The time variation of the brightness of the liquid crystal panel when a square wave with a voltage of ± 4 V and a frequency of 1 kHz was applied to a liquid crystal cell to which no voltage was applied was captured with an oscilloscope. When no voltage was applied, the luminance was 0%, a voltage of ± 4 V was applied, the saturated luminance value was 100%, and the time for the luminance to change from 10% to 90% was defined as the rising response speed.

  As can be seen from Table 1, in the liquid crystal cell of the example, even when the polymerizable compound was reduced to 0.05% by weight, the response speed after UV irradiation was the same as when the polymerizable compound was 0.2% by weight. Improved. Furthermore, even when the polymerizable compound was 0.02% by weight, the response speed was improved. Furthermore, the response speed was improved even when a liquid crystal to which no polymerizable compound was added was used. In Examples 5 and 6, the response speed was greatly improved in the liquid crystal to which no polymerizable compound was added. On the other hand, in the comparative example, the response speed was not improved when the polymerizable compound was reduced or when the liquid crystal was not added.

The liquid crystal display device manufactured using the liquid crystal aligning agent of the present invention can improve the response speed and obtain a good alignment state even when the polymerizable compound is reduced in the PSA alignment method. Can provide a liquid crystal display element capable of obtaining characteristics equivalent to those of the PSA method even when a liquid crystal to which a polymerizable compound is not added is used. As a result, it is useful for PSA type TFT liquid crystal display elements, TN liquid crystal display elements, VA liquid crystal display elements, and the like.
The specification, claims and abstract of Japanese Patent Application No. 2009-112197 filed on May 1, 2009 and Japanese Patent Application No. 2009-249301 filed on October 29, 2009 are as follows. The entire contents are hereby incorporated by reference as the disclosure of the specification of the present invention.

Claims (10)

They include alkoxysilane represented by alkoxysilane and the following formula represented by the following formula (1) (2), in the total alkoxysilane, an alkoxysilane represented by the formula (2) is contained 10 to 60 mol% A liquid crystal aligning agent containing polysiloxane obtained by polycondensation of alkoxysilane is applied, and a liquid crystal cell sandwiched between two baked substrates is irradiated with UV while voltage is applied. The liquid crystal display element 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.)
R ³ Si (OR ⁴ ) ₃ (2)
(R ³ represents an alkyl group substituted with an acryl group or a methacryl group, and R ⁴ represents an alkyl group having 1 to 5 carbon atoms.) The liquid crystal display element according to claim 1, wherein the polysiloxane is obtained by polycondensation of an alkoxysilane containing an alkoxysilane represented by the following formula (3).
(R ⁵ ) _n Si (OR ⁶ ) _4-n (3)
(R ⁵ is a hydrogen atom or a hydrocarbon group having 1 to 16 carbon atoms which may be substituted with a hetero atom, a halogen atom, an amino group, a glycidoxy group, a mercapto group, an isocyanate group or a ureido group; R ⁶ is an alkyl group having 1 to 5 carbon atoms, and n represents an integer of 0 to 3. ^{3. The} alkoxysilane represented by the formula (1), wherein R ¹ in the formula (1) is a hydrocarbon group having 8 to 22 carbon atoms, and R ² is methyl or ethyl. Liquid crystal display element . The alkoxysilane represented by the formula (2) is composed of 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-methacryloxypropyltriethoxysilane. The liquid crystal display element according to claim 1, which is at least one selected from the group. The liquid crystal display element in any one of Claims 2-4 whose R < ⁵ > of the alkoxysilane represented by the said Formula (3) is a C1-C6 hydrocarbon group. The liquid crystal display element according to claim 2, wherein the alkoxysilane represented by the formula (3) is a tetraalkoxysilane in which n in the formula (3) is 0. The alkoxysilane represented by the formula (1) is contained in an amount of 0.1 to 30 mol% in the total alkoxysilane, and the alkoxysilane represented by the formula (2) is 3 to 60 in the total alkoxysilane. The liquid crystal display element according to claim 1, wherein the liquid crystal display element is contained in mol%. The liquid crystal display element according to any one of claims 2 to 7, wherein the alkoxysilane represented by the formula (3) is contained in an amount of 10 to 96.9 mol% in all alkoxysilanes. The liquid crystal display element according to claim 1, wherein the content of polysiloxane is 0.5 to 15% by mass in terms of SiO ₂ . An alkoxysilane represented by the following formula (1) and an alkoxysilane represented by the following formula (2) are included, and 10-60 mol% of the alkoxysilane represented by the formula (2) is contained in all alkoxysilanes. A liquid crystal display characterized by applying a liquid crystal alignment agent containing polysiloxane obtained by polycondensation of alkoxysilane, sandwiching the liquid crystal between two baked substrates, and irradiating UV with voltage applied Device manufacturing method.
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.)
R ³ Si (OR ⁴ ) ₃ (2)
(R ³ represents an alkyl group substituted with an acryl group or a methacryl group, and R ⁴ represents an alkyl group having 1 to 5 carbon atoms.)