JP5999084B2 - 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 alignment agent containing polysiloxane obtained by polycondensation of alkoxysilane, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film.

In recent years, among the liquid crystal display element display methods, the 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 projection for controlling the direction in which the liquid crystal falls is formed on the TFT plate or the color filter substrate, or the direction in which the liquid crystal falls by the electric field by forming a slit in the ITO electrode of the substrate. A PVA (patterned vertical alignment) system to be controlled is known.

  As another alignment method, there is a PSA (Polymer sustained 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 a 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 falls down. 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. It is possible to operate with a structure in which a slit is made in one electrode constituting the liquid crystal panel, and the electrode pattern on the opposite side is not provided with a protrusion such as MVA or a slit such as PVA, and the manufacturing is simplified and excellent. The panel transmittance is obtained. (See Patent Document 1)

  Inorganic liquid crystal alignment film materials are known together with organic liquid crystal alignment film materials such as polyimide that have been used conventionally. For example, as a material for a coating-type inorganic alignment film, an alignment agent composition containing a reaction product of tetraalkoxysilane, trialkoxysilane, alcohol, and oxalic acid has been proposed. It has been reported that a liquid crystal alignment film excellent in vertical alignment, heat resistance and uniformity is formed. (See Patent Document 2)

  In addition, a liquid crystal aligning agent composition containing a reaction product of tetraalkoxysilane, specific trialkoxysilane and water and a specific glycol ether solvent has been proposed to prevent display failure and afterimage characteristics even after long-time driving. It has been reported that a liquid crystal alignment film is formed without decreasing the ability to align liquid crystal and having little decrease in voltage holding ratio against light and heat. (See Patent Document 3)

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

  In the 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. With respect to this problem, by introducing a side chain that undergoes a polymerization reaction into the alignment film, characteristics equivalent to those of the PSA method can be obtained even when a liquid crystal to which no polymerizable compound is added is used.

  In the VA mode in which the vertical alignment is performed, a strong vertical alignment force is required for the vertical alignment. However, in this method without using a polymerizable compound, the response speed after UV irradiation becomes slow when the vertical alignment force is improved. Thus, when the response speed after UV irradiation is improved, the vertical alignment force decreases. The improvement in the vertical alignment force and the response speed after UV irradiation has a trade-off relationship.

  An object of the present invention is to use a liquid crystal to which a polymerizable compound is not added and treat the same as in the PSA method to improve the response speed after UV irradiation without reducing the vertical alignment force. It is to provide a liquid crystal alignment agent capable of forming a liquid crystal alignment film capable of improving the response speed after UV irradiation, and a liquid crystal display element having a liquid crystal alignment film obtained from the liquid crystal alignment agent. .

The gist of the present invention is as follows.
[1] A liquid crystal aligning agent containing the following polysiloxane (A) and polysiloxane (B).
Polysiloxane (A): A polysiloxane obtained by polycondensation of an alkoxysilane represented by the formula (1) and an alkoxysilane containing the alkoxysilane represented by the formula (2).
R ¹ Si (OR ² ) ₃ (1)
(R ¹ is an optionally substituted hydrocarbon group having 8 to 30 carbon atoms, and R ² represents an alkyl group having 1 to 5 carbon atoms.)
R ³ Si (OR ⁴ ) ₃ (2)
^{(R 3} is acryl group, an alkyl group has been C1-30 substituted methacrylic group or a styryl group, ^{R 4} represents an alkyl group having 1 to 5 carbon atoms.)
Polysiloxane (B): polysiloxane obtained by polycondensation of alkoxysilane containing 70% to 100% of alkoxysilane represented by formula (3).
Si (OR ⁵ ) ₄ (3)
(R ⁵ represents an alkyl group having 1 to ⁵ carbon atoms.)

[2] The liquid crystal aligning agent according to [1], wherein the polysiloxane (B) is a polysiloxane obtained by polycondensation of an alkoxysilane containing an alkoxysilane represented by the formula (2).
[3] The liquid crystal aligning agent according to [1], wherein the polysiloxane (B) is a polysiloxane obtained by polycondensation of an alkoxysilane containing an alkoxysilane represented by the formula (4).
R ⁶ Si (OR ⁷ ) ₃ (4)
(R ⁶ is an alkyl group having 1 to 5 carbon atoms, and R ⁷ represents an alkyl group having 1 to 5 carbon atoms.)
[4] A polysiloxane obtained by polycondensing an alkoxysilane containing an alkoxysilane represented by the following formula (5), wherein at least one polysiloxane selected from polysiloxane (A) and polysiloxane (B) The liquid crystal aligning agent in any one of said [1]-[3] which is siloxane.
(R ⁸ ) _n Si (OR ⁹ ) _4-n (5)
(R ⁸ is a hydrogen atom or a hydrocarbon group having 1 to 12 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; ⁹ is an alkyl group having 1 to 5 carbon atoms, and n represents an integer of 0 to 3.)

[5] The alkoxysilane represented by the formula (1) is contained in an amount of 1 mol% to 20 mol% in the total alkoxysilane used in the polysiloxane (A), and is represented by the formula (2). The liquid crystal aligning agent in any one of said [1]-[3] in which 10 mol%-80 mol% are contained in all the alkoxysilanes used for polysiloxane (A).
[6] A liquid crystal alignment film obtained from the liquid crystal aligning agent according to any one of [1] to [5].
[7] A liquid crystal display device having the liquid crystal alignment film according to [6].
[8] A liquid crystal display element that applies the liquid crystal aligning agent according to any one of [1] to [5], sandwiches liquid crystal between two baked substrates, and irradiates UV in a state where a voltage is applied. Production method.

  According to the present invention, it is possible to improve the response speed after UV irradiation without reducing the vertical alignment force by irradiating UV similarly to the PSA method using a liquid crystal to which no polymerizable compound is added. A liquid crystal aligning agent capable of forming a liquid crystal aligning film and a liquid crystal display element having a liquid crystal aligning film obtained from the liquid crystal aligning agent can be obtained.

<Polysiloxane (A)>
The polysiloxane (A) is a polysiloxane obtained by polycondensation of an alkoxysilane represented by the formula (1) and an alkoxysilane containing the alkoxysilane represented by the formula (2).
R ¹ Si (OR ² ) ₃ (1)
In Formula (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)
In formula (2), R ³ is an alkyl group substituted with an acryl group, a methacryl group or a styryl group, and R ⁴ represents an alkyl group having 1 to 5 carbon atoms.

R ^{1 of the} alkoxysilane represented by the formula (1) (hereinafter also referred to as a specific organic group) is a hydrocarbon group having 8 to 30 carbon atoms, preferably 8 to 22 carbon atoms which may be substituted with fluorine. There is no particular limitation as long as it has the effect of vertically aligning the liquid crystal.
Examples of the specific organic group 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 the fluoroalkyl group, the number of fluorine atoms is 1 or more, and all hydrogens may be substituted with fluorine atoms.
In particular, alkoxysilane in which R ¹ is an alkyl group is preferable. The polysiloxane (A) 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 Lodecyltriethoxysilane, isooctyltriethoxysilane, phenethyltriethoxysilane, pentafluorophenylpropyltrimethoxysilane, m-styrylethyltrimethoxysilane, p-styrylethyltrimethoxysilane, (1-naphthyl) triethoxysilane, ( 1-naphthyl) trimethoxysilane and the like. 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 1 mol% or more in order to obtain good liquid crystal alignment in all alkoxysilanes used for obtaining the polysiloxane (A). . More preferably, it is 1.5 mol% or more. More preferably, it is 2 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 25 mol% or less.
R ^{3 of the} alkoxysilane represented by the formula (2) (hereinafter also referred to as a second specific organic group) is an acrylic group (also referred to as an acryloyl group or an acryloxy group) , a methacryl group (also referred to as a methacryloyl group or a methacryloxy group ). And an alkyl group substituted with at least one selected from the group consisting of styryl groups. The number of substituted hydrogen atoms is one or more, preferably one. 1-30 are preferable and, as for carbon number of an alkyl group, More preferably, it is 1-20. More preferably, it is 1-10. The alkyl group may be linear or branched, but is more preferably linear.
R ⁴ of the alkoxysilane represented by the formula (2) is an alkyl group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, and particularly preferably 1 to 2 carbon atoms.

  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 Silane, acryloxyethyltrimethoxysilane, acryloxyethyltriethoxysilane, styrylethyltrimethoxysilane, styrylethyltriethoxysilane, and 3- (N-styrylmethyl-2-aminoethylamino) propyltrimethoxysilane.

For the production of polysiloxane (A), in addition to the alkoxysilanes represented by the formulas (1) and (2), the effects of the present invention are intended for the purpose of improving the adhesion with the substrate and the affinity with the liquid crystal molecules. 1 or a plurality of alkoxysilanes represented by the following formula (5) can also be used. Since the alkoxysilane represented by the formula (5) can impart various characteristics to the polysiloxane, one or more kinds can be selected and used according to the required characteristics.
(R ⁸ ) _n Si (OR ⁹ ) _4-n (5)
In formula (5), R ⁸ is a hydrogen atom or a hydrocarbon having 1 to 10 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. It is a group.
R ⁹ is an alkyl group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms.
n is an integer of 0 to 3, preferably 0 to 2.

R ⁸ of the alkoxysilane represented by the formula (5) is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms (hereinafter also referred to as a third specific organic group).
Examples of the third specific organic group include an aliphatic hydrocarbon group; a hydrocarbon group having a ring structure such as an aliphatic ring, an aromatic ring and a heterocyclic ring; a hydrocarbon group having an unsaturated bond; an oxygen atom, nitrogen It is a C1-C6 hydrocarbon group which may contain hetero atoms, such as an atom and a sulfur atom, and may have a branched structure. The third specific 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 (5) below is given, it is not limited to this. 3- (2-aminoethylaminopropyl) trimethoxysilane, 3- (2-aminoethylaminopropyl) triethoxysilane, 2-aminoethylaminomethyltrimethoxysilane, 2- (2-aminoethylthioethyl) triethoxy Silane, 3-mercaptopropyltriethoxysilane, mercaptomethyltrimethoxysilane, vinyltriethoxysilane, 3-isocyanatopropyltriethoxysilane, trifluoropropyltrimethoxysilane, chloropropyltriethoxysilane, bromopropyltriethoxysilane, 3- Mercaptopropyltrimethoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, diethyldiethoxysilane, diethyldimethoxysilane, diphenyldimethoxysilane, diphenyldiet Sisilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyldimethylethoxysilane, trimethylethoxysilane, trimethylmethoxysilane, γ-ureidopropyltriethoxysilane, γ-ureidopropyltrimethoxysilane and γ-ureidopropyltripropoxysilane Etc.

In the alkoxysilane represented by the formula (5), the alkoxysilane in which n is 0 is tetraalkoxysilane. Tetraalkoxysilane is preferable for obtaining the polysiloxane (A) of the present invention because it easily condenses with the alkoxysilane represented by the formulas (1) to (4).
In such a formula (5), as alkoxysilane whose n is 0, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, or tetrabutoxysilane is more preferable, and tetramethoxysilane or tetraethoxysilane is particularly preferable. .
In the present invention, the alkoxysilane represented by the formula (1) is preferably 1 mol% to 20 mol%, particularly preferably 2 mol% to 20 in the total alkoxysilane used for the production of the polysiloxane (A). The alkoxysilane which is contained in mol% and represented by the formula (2) is 10 mol% to 80 mol%, particularly preferably 30 mol% to 80 mol in all alkoxysilanes used for the production of the polysiloxane (A). It is preferably contained in mol%.

<Polysiloxane (B)>
The polysiloxane (B) is a polysiloxane obtained by polycondensation of an alkoxysilane containing 70% by weight to 100% by weight of the alkoxysilane represented by the formula (3).
Si (OR ⁵ ) ₄ (3)
In Formula (3), R ⁵ represents an alkyl group having 1 to ⁵ carbon atoms, and preferably 1 or 2 carbon atoms.
As specific examples of the alkoxysilane represented by the formula (3), tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, or tetrabutoxysilane is more preferable, and tetramethoxysilane or tetraethoxysilane is particularly preferable.

The polysiloxane (B) may be a polysiloxane obtained by polycondensing an alkoxysilane containing an alkoxysilane represented by the formula (2) in addition to the alkoxysilane represented by the formula (3). good.
As the alkoxysilane represented by the formula (2) contained in the polysiloxane (B), the alkoxysilane used in the production of the polysiloxane (A) can be used. The specific examples are the same as described above.

The polysiloxane (B) may be a polysiloxane obtained by polycondensing an alkoxysilane containing an alkoxysilane represented by the formula (4) in addition to the alkoxysilane represented by the formula (3). good.
R ⁶ Si (OR ⁷ ) ₃ (4)
In Formula (4), R ⁶ is an alkyl group having 1 to 5 carbon atoms, and R ⁷ represents an alkyl group having 1 to 5 carbon atoms.
R ⁶ of the alkoxysilane represented by the formula (4) is an alkyl group having 1 to 5 carbon atoms. 1-4 are preferable, as for carbon number of an alkyl group, More preferably, it is 1-3.
R ⁷ of the alkoxysilane represented by the formula (4) is an alkyl group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, and particularly preferably 1 to 2 carbon atoms.

Although the specific example of the alkoxysilane represented by Formula (4) is given, it is not limited to these. For example, methyltriethoxysilane, methyltrimethoxysilane, dimethyltrimethoxysilane, dimethyltriethoxysilane, n-propyltrimethoxysilane, and n-propyltriethoxysilane.
In particular, in addition to the alkoxysilane represented by the formula (3), a liquid crystal aligning agent containing a polysiloxane (B) obtained by polycondensation of an alkoxysilane containing an alkoxysilane represented by the formula (4) Is particularly desirable because of its high vertical alignment force.

  In order to improve the response speed of the liquid crystal display element by applying UV light while applying a voltage using a liquid crystal to which no polymerizable compound is added, it is expressed by the formula (2) having the second specific organic group. The alkoxysilane to be used is preferably 10 mol% or more in all alkoxysilanes used for obtaining the polysiloxane (B). More preferably, it is 20 mol% or more. More preferably, it is 30 mol% or more. Moreover, in order to fully harden the liquid crystal aligning film formed, 75 mol% or less is preferable.

For the production of polysiloxane (B), in addition to the alkoxysilanes represented by formula (2), formula (3), and formula (4), the purpose is to improve adhesion to the substrate and affinity with liquid crystal molecules. As long as the effect of the present invention is not impaired, one or more alkoxysilanes represented by the following formula (5) can be used. Since the alkoxysilane represented by the formula (5) can impart various characteristics to the polysiloxane, one or more kinds can be selected and used according to the required characteristics.
(R ⁸ ) _n Si (OR ⁹ ) _4-n (5)
In formula (5), the structures and preferred ranges of R ⁸ and R ⁹ and specific examples of alkoxysilanes represented by formula (5) are as described above.
<Method for producing polysiloxane>

  The method for obtaining the polysiloxane used in the present invention is not particularly limited. In the polysiloxane (A) of the present invention, the alkoxysilane having the above-described formulas (1) and (2) as essential components is used, and in the polysiloxane (B), the above-described formula (3) is used as an essential component. An alkoxysilane is obtained by polycondensation 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 alkoxysilane include a method of hydrolyzing and condensing 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.
In the present invention, the amount of water used in the above reaction can be appropriately selected as desired, but usually it is preferably 0.5 to 2.5 times mol of all alkoxy groups in the alkoxysilane. 1-fold mole to 2-fold mole is more preferred.

  Usually, for the purpose of promoting hydrolysis / condensation reaction, acids such as hydrochloric acid, sulfuric acid, nitric acid, acetic acid, formic acid, succinic acid, maleic acid, fumaric acid; alkalis such as ammonia, methylamine, ethylamine, ethanolamine, triethylamine A metal salt such as hydrochloric acid, sulfuric acid or nitric acid; In addition, it is also common to further promote the hydrolysis / condensation reaction 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, the amount of succinic acid to be used is preferably 0.2 mol to 2 mol, more preferably 0.5 mol to 1.5 mol, relative to 1 mol of all alkoxy groups of the alkoxysilane. Heating in this method can be performed at a liquid temperature of 50 ° C to 180 ° C. Preferably, it is a method of heating for several tens of minutes to several tens of hours under reflux so that the liquid does not evaporate or volatilize.

In the case of using a plurality of types of alkoxysilanes when obtaining polysiloxane, the alkoxysilanes may be mixed in advance and used as a mixture, or a plurality of types of alkoxysilanes may be sequentially mixed and used.
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 melt | dissolves as the polycondensation reaction of alkoxysilane progresses is sufficient. In general, alcohol is produced by polycondensation reaction of alkoxysilane, and therefore alcohols, glycols, glycol ethers, or organic solvents having good compatibility with alcohols are used, and glycols are particularly preferably used. It is done.

  Specific examples of such a polymerization solvent include alcohols such as methanol, ethanol, propanol, butanol, 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 Glycols such as 1,5-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 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 weight or less, more preferably 5% by weight to 15% by weight. 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. If necessary, the solution obtained by the above method may be concentrated, diluted by adding a solvent, or substituted with another solvent to obtain a polysiloxane solution.
In that case, the solvent to be used (hereinafter also referred to as 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 present invention, as long as the effects of the present invention are not impaired, other components other than polysiloxane, for example, inorganic fine particles, metalloxane oligomers, metalloxane polymers, leveling agents, and surfactants are further composed of polysiloxane. It may be contained in the solution.
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 μm to 0.2 μm, more preferably 0.001 μm 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; And 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 the metalloxane polymer, single or composite oxide precursors such as silicon, titanium, aluminum, tantalum, antimony, bismuth, tin, indium, and zinc are used. The metalloxane oligomer and the metalloxane polymer may be commercially available products or may be obtained from monomers such as metal alkoxides, nitrates, hydrochlorides, and carboxylates by a conventional method such as hydrolysis. .

Specific examples of commercially available metalloxane oligomers and metalloxane polymers include siloxane oligomers 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 siloxane polymer and titanium-n-butoxide tetramer manufactured by Kanto Chemical. 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 the polysiloxane may be simultaneous with or after the polysiloxane, and is not particularly limited.

[Liquid crystal aligning agent]
The liquid crystal aligning agent of this invention is the solution containing the polysiloxane mentioned above and other components as needed. In this case, as the solvent, a solvent selected from the group consisting of the above-mentioned polysiloxane polymerization solvent and additive solvent is used.
The total content of the polysiloxane in the liquid crystal aligning agent, SiO ₂ conversion concentration is preferably 0.5 wt% to 15 wt%, more preferably from 1% to 6% by weight. Within such a SiO ₂ equivalent concentration range, it is easy to obtain a desired film thickness by a single application, and a sufficient pot life (pot life) of the solution is likely to be obtained.

The liquid crystal aligning agent of the present invention contains polysiloxane (A) and polysiloxane (B) as a total polysiloxane in a weight ratio of 10:90 to 50:50, preferably 20:80 to 40:60. To do.
Moreover, the weight ratio of all the polysiloxanes in the liquid crystal aligning agent of this invention and the other component added as needed is 99: 1-50: 50, Preferably 98: 2-70: 30.
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 of the alkoxysilane mentioned above and the addition solvent of polysiloxane can be used.

[Liquid crystal alignment film]
The liquid crystal aligning film of this invention is obtained using the liquid crystal aligning agent of this invention. 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, this cured film is rubbed, irradiated with polarized light or light of a specific wavelength, processed with an ion beam, etc., and irradiated with UV in a state where a voltage is applied to the liquid crystal display element after filling the liquid crystal. It is also possible to do.

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 minutes to 30 minutes, preferably 1 minute to 5 minutes.

  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 minutes-90 minutes, More preferably, it is 20 minutes-80 minutes. For the heating, a generally known method such as a hot plate, a hot air circulation oven, an IR (infrared) 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, which is preferable because the reliability of the liquid crystal display element can be easily obtained. Further, the thickness of the cured film is preferably 300 nm or less, more preferably 150 nm or less, and the power consumption of the liquid crystal display element does not become extremely large.

<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 μm to 30 μm, preferably 2 μm 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 the liquid crystal cell in which the liquid crystal is introduced, UV irradiation is performed while a voltage is applied between the electrodes on both sides of the substrate, whereby acrylic groups, methacryl groups, etc. in the alignment film are polymerized in situ and crosslinked. The response speed of the display becomes faster. Here, the applied voltage is 5 Vp-p to 50 Vp-p, and preferably 5 Vp-p to 30 Vp-p. The UV irradiation amount to be irradiated is 1 J (joule) to 60 J, but preferably 40 J or less. A smaller UV irradiation amount is preferable because it can suppress a decrease in reliability due to destruction of members constituting the liquid crystal display and can reduce a UV irradiation time, thereby increasing a manufacturing tact (operation amount).

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]. A substrate having an electrode pattern or a projection pattern such as standard PVA or MVA can also be used.
As a substrate used for a liquid crystal display element, a line / slit electrode pattern of 1 μm to 10 μm is formed on one side substrate, and a slit pattern or a projection pattern is not formed on the opposite substrate, similar to a PSA type liquid crystal display. The liquid crystal display with this structure can simplify the manufacturing process and obtain high transmittance.

In a high-performance liquid crystal display element such as a TFT type liquid crystal display element, a transistor element formed on a substrate between an electrode for driving liquid crystal and the 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, a material such as aluminum that reflects light only on one substrate is used. It is also possible to use an opaque substrate such as a silicon wafer.

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 MPMS: 3-methacryloxypropyltrimethoxysilane MTES: methyltriethoxysilane HG: 2-methyl-2,4-pentanediol ( (Alternative name: hexylene glycol)
BCS: 2-butoxyethanol UPS: 3-ureidopropyltriethoxysilane

<Synthesis Example 1>
Mix 20.6 g of HG, 6.9 g of BCS, 18.3 g of TEOS, 4.2 g of C18, and 23.4 g of ACPS in a 200 mL four-necked reaction flask equipped with a thermometer and reflux tube. Thus, a solution of the alkoxysilane monomer was prepared. To this solution, a solution of 10.3 g of HG, 3.4 g of BCS, 10.8 g of water and 1.4 g of oxalic acid as a catalyst was added dropwise over 30 minutes at room temperature, Stir at room temperature for 30 minutes. Then, after heating using an oil bath and refluxing for 30 minutes, 0.6 g of a methanol solution with a UPS content of 92% by mass, 0.3 g of HG, and 0.1 g of BCS were mixed in advance. Was added. 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.

10.0 g of the obtained polysiloxane solution and 20.0 g of BCS were mixed to obtain a liquid crystal aligning agent intermediate (S1) having a SiO ₂ equivalent concentration of 4% by weight.
In addition, in a 200 mL four-necked reaction flask equipped with a thermometer and a reflux tube, 23.6 g of HG, 7.9 g of BCS, and 41.2 g of TEOS were mixed to prepare a solution of an alkoxysilane monomer. did. To this solution, 11.8 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, Stir at room temperature for 30 minutes. Then, after heating using an oil bath and refluxing for 30 minutes, 0.6 g of a methanol solution with a UPS content of 92% by mass, 0.3 g of HG, and 0.1 g of BCS were mixed in advance. Was added. 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.
10.0 g of the obtained polysiloxane solution and 20.0 g of BCS were mixed to obtain a liquid crystal aligning agent intermediate (U1) having a SiO ₂ equivalent concentration of 4% by weight. The obtained liquid crystal aligning agent intermediate (S1) and liquid crystal aligning agent intermediate (U1) were mixed at a ratio of 3: 7 (weight ratio, the same applies hereinafter), and the SiO ₂ equivalent concentration was 4% by weight. A liquid crystal aligning agent [K1] was obtained.

<Synthesis Example 2>
Mix 19.9 g of HG, 6.6 g of BCS, 18.3 g of TEOS, 4.2 g of C18, and 24.8 g of MPMS in a 200 mL four-necked reaction flask equipped with a thermometer and reflux tube. Thus, a solution of the alkoxysilane monomer was prepared. To this solution, 10.0 g of HG, 3.3 g of BCS, 10.8 g of water, and 1.4 g of oxalic acid as a catalyst were added dropwise over 30 minutes at room temperature, Stir at room temperature for 30 minutes. Then, after heating using an oil bath and refluxing for 30 minutes, 0.6 g of a methanol solution with a UPS content of 92% by mass, 0.3 g of HG, and 0.1 g of BCS were mixed in advance. Was added. 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.
10.0 g of the obtained polysiloxane solution and 20.0 g of BCS were mixed to obtain a liquid crystal aligning agent intermediate (S2) having a SiO ₂ equivalent concentration of 4% by weight. The obtained liquid crystal aligning agent intermediate (S2) and the liquid crystal aligning agent intermediate (U1) obtained in Synthesis Example 1 were mixed at a ratio of 3: 7, and the liquid crystal aligning agent having a SiO ₂ equivalent concentration of 4% by weight. [K2] was obtained.

<Synthesis Example 3>
In a 200 mL four-necked reaction flask equipped with a thermometer and a reflux tube, 23.3 g of HG, 7.8 g of BCS, 39.2 g of TEOS, and 2.5 g of MPMS were mixed to obtain an alkoxysilane monomer. A solution of was prepared. To this solution, 11.7 g of HG previously mixed, 3.9 g of BCS, 10.8 g of water, and 0.4 g of oxalic acid as a catalyst were added dropwise over 30 minutes at room temperature. Stir at room temperature for 30 minutes. Then, after heating using an oil bath and refluxing for 30 minutes, 0.6 g of a methanol solution with a UPS content of 92% by mass, 0.3 g of HG, and 0.1 g of BCS were mixed in advance. Was added. 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.
10.0 g of the obtained polysiloxane solution and 20.0 g of BCS were mixed to obtain a liquid crystal aligning agent intermediate (U2) having a SiO ₂ equivalent concentration of 4% by weight. The liquid crystal aligning agent intermediate (S1) obtained in Synthesis Example 1 and the obtained liquid crystal aligning agent intermediate (U2) are mixed at a ratio of 3: 7, and the SiO ₂ equivalent concentration is 4% by weight. [K3] was obtained.

<Synthesis Example 4>
The liquid crystal aligning agent intermediate (S2) obtained in Synthesis Example 2 and the liquid crystal aligning agent intermediate (U2) obtained in Synthesis Example 3 were mixed at a ratio of 3: 7, and the SiO ₂ equivalent concentration was 4% by weight. Liquid crystal aligning agent [K4] was obtained.

<Synthesis Example 5>
In a 200 mL four-necked reaction flask equipped with a thermometer and a reflux tube, 23.8 g of HG, 7.9 g of BCS, 37.1 g of TEOS, and 3.6 g of MTES were mixed to obtain an alkoxysilane monomer. A solution of was prepared. To this solution, 1.9 g of HG, 4.0 g of BCS, 10.8 g of water, and 0.4 g of oxalic acid as a catalyst were added dropwise over 30 minutes at room temperature, Stir at room temperature for 30 minutes. Thereafter, the mixture was heated using an oil bath and refluxed for 30 minutes. Then, a premixed mixture of a methanol solution 0.6 g of UPS content 92 mass%, HG 0.3 g, and BCS 0.1 g was added. added. 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.
10.0 g of the obtained polysiloxane solution and 20.0 g of BCS were mixed to obtain a liquid crystal aligning agent intermediate (U3) having a SiO ₂ equivalent concentration of 4% by weight. The liquid crystal aligning agent intermediate (S1) obtained in Synthesis Example 1 and the obtained liquid crystal aligning agent intermediate (U3) are mixed at a ratio of 3: 7, and the SiO ₂ equivalent concentration is 4% by weight. [K5] was obtained.

<Synthesis Example 6>
The liquid crystal aligning agent intermediate (S2) obtained in Synthesis Example 2 and the liquid crystal aligning agent intermediate (U3) obtained in Synthesis Example 5 were mixed at a ratio of 3: 7, and the SiO ₂ equivalent concentration was 4% by weight. Liquid crystal aligning agent [K6] was obtained.

<Comparative Synthesis Example 1>
In a 200 mL four-necked reaction flask equipped with a thermometer and a reflux tube, 22.6 g of HG, 7.5 g of BCS, and 39.6 g of TEOS were mixed to prepare an alkoxysilane monomer solution. To this solution, 11.3 g of HG, 3.8 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, Stir at room temperature for 30 minutes. Then allowed to cool was refluxed for 1 hour and heated using an oil bath, SiO ₂ conversion concentration was obtained 12 wt% of a polysiloxane solution.
10.0 g of the obtained polysiloxane solution and 20.0 g of BCS were mixed to obtain a liquid crystal aligning agent [L1] having a SiO ₂ equivalent concentration of 4% by weight.

<Comparative Synthesis Example 2>
A liquid crystal aligning agent [L2] was obtained in the same manner as the liquid crystal aligning agent intermediate (S1) obtained in Synthesis Example 1.
<Comparative Synthesis Example 3>
A liquid crystal aligning agent [L3] was obtained in the same manner as the liquid crystal aligning agent intermediate (S2) obtained in Synthesis Example 2.

<Example 1>
Spin the liquid crystal aligning agent [K1] obtained in Synthesis Example 1 onto the ITO surface of the ITO electrode substrate on which an ITO electrode pattern having a pixel size of 100 microns × 300 microns and a line / space of 5 microns is formed. Coated. After drying for 2 minutes on a hot plate at 80 ° C., baking was performed in a hot air circulation oven at 200 ° C. or 220 ° 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 was spin-coated on the ITO surface on which no electrode pattern was formed, dried on an 80 ° C. hot plate for 2 minutes, and then 200 ° C. or 220 like the above substrate. Baking was performed for 30 minutes in a hot air circulation oven at 0 ° C. 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. Liquid crystal MLC-6608 (trade name, manufactured by Merck & Co., Inc.) was injected into the empty cell by a reduced pressure injection method to produce a liquid crystal cell.
The response speed characteristics of the obtained liquid crystal cell were measured by the method described later. Thereafter, UV (wavelength; using a 365 nm bandpass filter) 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 characteristic was measured again, and the response speed before and after UV irradiation was compared. The results are shown in Table 1.
Further, the vertical alignment of the cells was also measured and evaluated by the method described later. The results are also shown in Table 1.

<Example 2>
A liquid crystal cell was prepared in the same manner as in Example 1 except that the liquid crystal alignment treatment agent [K1] was changed to the liquid crystal alignment treatment agent [K2] obtained in Synthesis Example 2, and the response speed was measured. The results are shown in Table 1.
<Example 3>
A liquid crystal cell was prepared in the same manner as in Example 1 except that the liquid crystal alignment treatment agent [K1] was changed to the liquid crystal alignment treatment agent [K3] obtained in Synthesis Example 3, and the response speed was measured. The results are shown in Table 1.

<Example 4>
A liquid crystal cell was prepared in the same manner as in Example 1 except that the liquid crystal alignment treatment agent [K1] was changed to the liquid crystal alignment treatment agent [K4] obtained in Synthesis Example 4, and the response speed was measured. The results are shown in Table 1.
<Example 5>
A liquid crystal cell was produced in the same manner as in Example 1 except that the liquid crystal alignment treatment agent [K1] was changed to the liquid crystal alignment treatment agent [K5] obtained in Synthesis Example 5, 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 1 except that the liquid crystal alignment treatment agent [K1] was changed to the liquid crystal alignment treatment agent [K6] obtained in Synthesis Example 6, and the response speed was measured. The results are shown in Table 1.

<Comparative Example 1>
A liquid crystal cell was prepared in the same manner as in Example 1 except that the liquid crystal alignment treatment agent [K1] was changed to the liquid crystal alignment treatment agent [L1] obtained in Comparative Synthesis Example 1, and the response speed was measured. The results are shown in Table 1.
<Comparative example 2>
A liquid crystal cell was produced in the same manner as in Example 1 except that the liquid crystal alignment treatment agent [K1] was changed to the liquid crystal alignment treatment agent [L2] obtained in Comparative Synthesis Example 2, and the response speed was measured. The results are shown in Table 1.
<Comparative Example 3>
A liquid crystal cell was prepared in the same manner as in Example 1 except that the liquid crystal alignment treatment agent [K1] was changed to the liquid crystal alignment treatment agent [L3] obtained in Comparative Synthesis Example 2, and the response speed was measured. The results are shown in Table 1.

[Response speed characteristics]
The change in luminance of the liquid crystal panel over time when a rectangular wave with a voltage of ± 4 V and a frequency of 1 kHz was applied to the liquid crystal cell to which no voltage was applied was captured with an oscilloscope. When the voltage was not 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 taken as the rising response speed.

[Vertical alignment]
For the evaluation of the vertical alignment, a cell was placed between two polarizing plates arranged in crossed Nicols and observed, and whether or not black display was shown was determined. Even if the firing temperature was raised, the vertical alignment was higher as the vertical alignment was higher.

×：垂直配向を示さない
○：２００℃又は２２０℃３０分の焼成において垂直配向を示す
◎：２２０℃、６０分の焼成においても垂直配向を示す

×: No vertical alignment ○: Vertical alignment is exhibited in baking at 200 ° C. or 220 ° C. for 30 minutes A: Vertical alignment is exhibited even in baking at 220 ° C. for 60 minutes

  As can be seen from Table 1, the liquid crystal cell of the example showed vertical alignment even when baked at 220 ° C., and the response speed was improved after UV irradiation. In particular, the liquid crystal cells of Example 5 and Example 6 exhibited vertical alignment even when the 220 ° C. baking time was extended to 60 minutes. On the other hand, in Comparative Example 1, although the vertical alignment was exhibited by baking at 220 ° C., the response speed was not improved after UV irradiation. In Comparative Examples 2 and 3, the response speed was improved after UV irradiation, but no vertical alignment was exhibited in the case of baking at 220 ° C.

  The liquid crystal display device manufactured using the liquid crystal aligning agent of the present invention is a liquid crystal capable of obtaining characteristics equivalent to those of the PSA method even when a liquid crystal to which no polymerizable compound is added is used in the PSA method. A display element can be provided and can be used as a PSA TFT liquid crystal display element, a TN liquid crystal display element, a VA liquid crystal display element, or the like.

  It should be noted that the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2011-038413 filed on February 24, 2011 are incorporated herein as the disclosure of the specification of the present invention. Is.

Claims (8)

A liquid crystal aligning agent comprising the following polysiloxane (A) and polysiloxane (B).
Polysiloxane (A): A polysiloxane obtained by polycondensation of an alkoxysilane represented by the formula (1) and an alkoxysilane containing the alkoxysilane represented by the formula (2).
R ¹ Si (OR ² ) ₃ (1)
(R ¹ is an optionally substituted hydrocarbon group having 8 to 30 carbon atoms, and R ² represents an alkyl group having 1 to 5 carbon atoms.)
R ³ Si (OR ⁴ ) ₃ (2)
^{(R 3} is acryl group, an alkyl group has been C1-30 substituted methacrylic group or a styryl group, ^{R 4} represents an alkyl group having 1 to 5 carbon atoms.)
Polysiloxane (B): polysiloxane obtained by polycondensation of alkoxysilane containing 70% to 100% of alkoxysilane represented by formula (3).
Si (OR ⁵ ) ₄ (3)
(R ⁵ represents an alkyl group having 1 to 5 carbon atoms.)   The liquid crystal aligning agent according to claim 1, wherein the polysiloxane (B) is a polysiloxane obtained by polycondensation of an alkoxysilane containing an alkoxysilane represented by the formula (2). The liquid crystal aligning agent of Claim 1 whose polysiloxane (B) is polysiloxane obtained by polycondensing the alkoxysilane containing the alkoxysilane further represented by Formula (4).
R ⁶ Si (OR ⁷ ) ₃ (4)
(R ⁶ is an alkyl group having 1 to 5 carbon atoms, and R ⁷ represents an alkyl group having 1 to 5 carbon atoms.) At least one polysiloxane selected from polysiloxane (A) and polysiloxane (B) is a polysiloxane obtained by further polycondensing an alkoxysilane containing an alkoxysilane represented by the following formula (5). The liquid crystal aligning agent in any one of Claims 1-3.
(R ⁸ ) _n Si (OR ⁹ ) _4-n (5)
(R ⁸ is a hydrogen atom or a hydrocarbon group having 1 to 12 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; ⁹ is an alkyl group having 1 to 5 carbon atoms, and n represents an integer of 0 to 3.)   The alkoxysilane represented by the formula (1) is contained in 1 mol% to 20 mol% in the total alkoxysilane used in the polysiloxane (A), and the alkoxysilane represented by the formula (2) The liquid crystal aligning agent in any one of Claims 1-3 contained in 10 mol%-80 mol% in all the alkoxysilanes used for polysiloxane (A). The liquid crystal aligning film obtained from the liquid crystal aligning agent in any one of Claims 1-5.   The liquid crystal display element which has a liquid crystal aligning film of Claim 6.   A method for producing a liquid crystal display element, wherein the liquid crystal aligning agent according to claim 1 is applied, the liquid crystal is sandwiched between two baked substrates, and UV is irradiated in a state where a voltage is applied.