WO2014073537A1

WO2014073537A1 - Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display element

Info

Publication number: WO2014073537A1
Application number: PCT/JP2013/079922
Authority: WO
Inventors: 暁子若林; 大輔佐久間; 賢一元山; 浩二平賀; 橋本　淳; 智裕山口
Original assignee: 日産化学工業株式会社
Priority date: 2012-11-06
Filing date: 2013-11-05
Publication date: 2014-05-15
Also published as: KR102210175B1; KR20150082365A; TW201431957A; CN104903786B; TWI609925B; JP6459513B2; CN104903786A; JPWO2014073537A1

Abstract

Provided is a liquid crystal aligning agent. This liquid crystal aligning agent is capable of forming a liquid crystal alignment film that performs liquid crystal alignment control by means of light and improves response speed of liquid crystals, while suppressing decrease in photoreactivity; and this liquid crystal aligning agent contains a polysiloxane component (A) that is formed from a starting material alkoxysilane containing an alkoxysilane represented by formula (1) and an alkoxysilane represented by formula (3) and a polymerization inhibitor component (B). The polymerization inhibitor component (B) is contained as a constituent part of the polysiloxane component (A) or as a substance that is different from the polysiloxane component (A). Also provided is a liquid crystal display element of VA mode, which comprises a liquid crystal alignment film that is formed from this liquid crystal aligning agent. R¹Si(OR²)₃ (1)

Description

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

The present invention provides a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display capable of forming a liquid crystal alignment film that controls the alignment of liquid crystal by light while suppressing a decrease in photoreactivity and further improves the response speed of liquid crystal It relates to an element.

The liquid crystal display element is known as a light, thin, and low power consumption display device, and has been remarkably developed in recent years.

The liquid crystal display element is configured by sandwiching and enclosing a liquid crystal layer between a pair of substrates, and orienting liquid crystals in the liquid crystal layer in a predetermined direction between the substrates. In the liquid crystal display element, the liquid crystal responds and changes its orientation when a voltage is applied to electrodes provided on a pair of substrates.
The liquid crystal display element can display a desired image using a change in the orientation of the liquid crystal due to voltage application.

This liquid crystal display element has various liquid crystal modes in which the initial alignment state of liquid crystal molecules and the form of alignment change by voltage application are different. For example, as an initial alignment state of liquid crystal molecules, a TN (Twisted Nematic) mode in which the liquid crystal is twisted by 90 ° between a pair of substrates is known.

In recent years, among liquid crystal display element display methods, liquid crystal display elements in a vertical alignment (VA) mode in which liquid crystal molecules having negative dielectric anisotropy are aligned vertically to a substrate have been actively developed ( For example, see Patent Document 1 and Patent Document 2.)
In this VA mode liquid crystal display element, by applying a voltage, the vertically aligned liquid crystal changes its alignment so as to be parallel to the substrate while being uniformly inclined in a predetermined direction. The VA mode liquid crystal display element can realize a high contrast ratio, a wide viewing angle, and excellent response characteristics.

This VA mode liquid crystal display element is required to form a state in which the liquid crystal is substantially vertically aligned as an initial alignment state of the liquid crystal when no voltage is applied in order to enable the above-described change in the alignment of the liquid crystal. That is, the VA mode liquid crystal display element is required to form an alignment state in which the liquid crystal is slightly inclined from the normal direction of the substrate toward a predetermined direction in the plane as the initial alignment state of the liquid crystal.

In the VA mode liquid crystal display element, several methods for realizing the above-described substantially vertical alignment state of the liquid crystal are known.
For example, in a VA mode liquid crystal display element, there is known an MVA (Multi-domain Vertical Alignment) method in which a protrusion structure that realizes a substantially vertical alignment state of the liquid crystal described above is formed on a TFT substrate or a color filter substrate that sandwich the liquid crystal. Yes. Also known is a PVA (Patterned Vertical Alignment) system in which a slit structure is provided in an electrode made of ITO (Indium Tin Oxide) or the like of a substrate sandwiching a liquid crystal layer, and the tilt direction of the liquid crystal is controlled by a formed oblique electric field. . Furthermore, as another method, there is a PSA (Polymer sustained Alignment) method.

In this PSA method, a photopolymerizable compound is added to the liquid crystal, and an electric field is applied in a state where the liquid crystal layer is sandwiched between the substrates to tilt the liquid crystal. The liquid crystal layer is irradiated with light, for example, UV (ultraviolet rays) in a state where the liquid crystal is tilted and aligned. As a result, the photopolymerizable compound is photopolymerized, a pretilt angle is formed in the liquid crystal layer, the orientation direction of the liquid crystal that is tilted by voltage application is fixed, and the response speed of the liquid crystal is improved.

In the PSA method, there is no need to provide a structure in which a slit is formed in an electrode on a substrate constituting a liquid crystal display element or a protrusion structure like the MVA method in order to control the tilt alignment direction of liquid crystal by voltage application. For this reason, it has the characteristics that simplification of manufacturing and excellent panel transmittance can be obtained, and among the various methods described above for the VA mode liquid crystal display element, this is a technology that has attracted particular attention in recent years (Patent Literature). 1).

However, 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 and response speed cannot be obtained. In addition, the unreacted polymerizable compound remaining in the liquid crystal becomes an impurity in the liquid crystal, resulting in a problem that the reliability of the liquid crystal display element is lowered.

Therefore, a technique has been proposed in which the function of the polymerizable compound described above is introduced into a polymer as a side chain structure, a liquid crystal alignment film is formed from the polymer, and a VA mode liquid crystal display element is manufactured (see Patent Document 4). .
In this technique, a liquid crystal aligning agent using a polymer having a structure in which a photoreactive side chain is introduced into a polymer molecule is applied to a substrate. Then, a liquid crystal layer is sandwiched between liquid crystal alignment films formed by firing, and a liquid crystal display element is manufactured by irradiating ultraviolet rays while applying a voltage to the liquid crystal layer.
As a result, even in a configuration in which no polymerizable compound is added to the liquid crystal, the direction in which the liquid crystal is tilted and aligned is controlled by applying a voltage, and a liquid crystal display element having a high response speed can be obtained.

International Publication No. 2008/117615 Pamphlet Japanese Unexamined Patent Application Publication No. 2008-76950 Japanese Unexamined Patent Publication No. 2004-302061 Japanese Unexamined Patent Publication No. 2011-95967

As described above, in the liquid crystal alignment film using the polymer having a photoreactive side chain, it is not necessary to add a photopolymerizable compound to the liquid crystal unlike the PSA method, and the above-described precipitation problem does not occur. . And the liquid crystal display element which uses the liquid crystal aligning film using the polymer which has a photoreactive side chain implement | achieves the control of the inclination alignment direction of a liquid crystal, and the improvement of a response speed.

However, in a liquid crystal aligning agent using a polymer having a photoreactive side chain, when the coating film is formed on a substrate and heated, unnecessary components such as a solvent are removed and a crosslinking reaction between polymer components is performed. The photoreactive side chain may cause a thermal reaction. That is, the photoreactive side chain of the highly reactive polymer may cause unwanted reactions due to heat. As a result, in the liquid crystal alignment film after baking, the photoreactivity of the side chain is partially lost and lowered before the light irradiation that requires it. Even if such a liquid crystal alignment film with reduced photoreactivity is used, a liquid crystal layer is sandwiched, and light such as UV is irradiated while applying a voltage to the liquid crystal layer, the liquid crystal display element has a desired liquid crystal tilt. Improvement of orientation control and response speed cannot be realized.

Therefore, it is a liquid crystal alignment film used in a VA mode liquid crystal display element, which suppresses the reaction before light irradiation of the side chain contained therein, suppresses the decrease in photoreactivity, and controls the alignment and response speed of liquid crystal by light. There is a need for a liquid crystal alignment film that achieves improvement. That is, there is a demand for a liquid crystal aligning agent that forms a liquid crystal alignment film that suppresses a decrease in photoreactivity before light irradiation.

An object of the present invention is to provide a liquid crystal aligning agent capable of controlling the alignment of liquid crystal by light while suppressing a decrease in photoreactivity and further forming a liquid crystal alignment film that improves the response speed of the liquid crystal, and the liquid crystal aligning agent. An object of the present invention is to provide a liquid crystal alignment film obtained by use and a liquid crystal display element having the liquid crystal alignment film.

As a result of research and development to achieve the above object, the present inventor has reached the present invention that can achieve this object through the following processes.
A VA mode liquid crystal display element having a liquid crystal alignment film using a polymer having a structure in which a photoreactive side chain is introduced into a polymer molecule is configured by sandwiching a liquid crystal layer between the pair of liquid crystal alignment films. Then, a voltage is applied to the liquid crystal that is vertically aligned between a pair of liquid crystal alignment films to realize the desired tilted alignment state of the liquid crystal, and then irradiation with light such as UV is performed to polymerize the photoreactive side chain. Give rise to At this time, the polymerization reaction of the photoreactive side chain proceeds in a state where a part of the liquid crystal in the vicinity thereof is involved. As a result, the photopolymerization reaction of the photoreactive side chain fixes the alignment state of a part of the liquid crystal that is tilted. Therefore, a pretilt angle is formed in the liquid crystal layer sandwiched between the liquid crystal alignment films, and as a result, the response speed of the liquid crystal of the liquid crystal display element is significantly improved.

Therefore, it is desirable that the liquid crystal alignment film of the liquid crystal display element has a sufficient amount of photoreactive side chains. For example, the liquid crystal alignment film is formed by forming a coating film by applying a liquid crystal aligning agent and heating and baking. However, the photoreactive side chain also causes a polymerization reaction by heat. Therefore, after heating and baking of the above-mentioned coating film, a sufficient amount of side chains having photoreactivity do not remain in the liquid crystal alignment film at the stage of controlling the alignment of the liquid crystal by light irradiation. Sometimes. In particular, in order to achieve uniform film characteristics of the liquid crystal alignment film, baking may be performed at a high temperature and / or for a long time. In such a case, there are few photoreactive side chains remaining in the liquid crystal alignment film. As a result, the decrease in photoreactivity becomes remarkable. As a result, the desired alignment state of the liquid crystal cannot be realized, and the response speed of the liquid crystal cannot be sufficiently improved in the liquid crystal display element.

Therefore, the present inventors paid attention to introducing a polymerization inhibition function into the liquid crystal alignment film. That is, the liquid crystal aligning agent containing the component which shows a polymerization prohibition function with respect to the photoreactive side chain of a polymer is used for formation of a liquid crystal aligning film, and suppresses the thermal reaction of the polymer side chain before light irradiation. For example, when the side chain undergoes radical polymerization by heating and baking, a polymerization inhibiting component that captures radicals generated during the heating and baking and inactivates radical polymerization is used for forming the liquid crystal alignment film. By doing so, polymerization of the liquid crystal alignment film due to heat is suppressed, and the liquid crystal alignment film enables the control of the desired liquid crystal alignment by light irradiation, and as a result, the response speed of the liquid crystal can be improved. I found it.

The present invention is based on such knowledge and has the following gist.
(1) A polysiloxane component (A) formed from a raw material alkoxysilane containing an alkoxysilane represented by the following formula (1) and an alkoxysilane represented by the following formula (3), and a polymerization inhibiting component (B) And the polymerization-inhibiting component (B) is contained as a constituent part of the polysiloxane component (A) or as a substance different from the polysiloxane component (A).
R ¹ Si (OR ² ) ₃ (1)
(R ¹ is a group represented by the following formula (2), and R ² is an alkyl group having 1 to 5 carbon atoms.)

(Y ¹ is a single bond, — (CH ₂ ) _a — (a is an integer of 1 to 15), —O—, —CH ₂ O—, —COO— or —OCO—.
Y ² is a straight or branched hydrocarbon group having 3 to 8 carbon atoms containing a single bond or a double bond, or — (CR ¹⁷ R ¹⁸ ) _b — (b is an integer of 1 to 15 , R ¹⁷ and R ¹⁸ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
Y ³ is a single bond, — (CH ₂ ) _c — (c is an integer of 1 to 15), —O—, —CH ₂ O—, —COO— or —OCO—.
Y ⁴ is a divalent cyclic group selected from a single bond, a benzene ring, a cyclohexyl ring, and a heterocyclic ring, or a divalent organic group having 12 to 25 carbon atoms and having a steroid skeleton, on the cyclic group Arbitrary hydrogen atoms are substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom May be.
Y ⁵ is at least one divalent cyclic group selected from the group consisting of a benzene ring, a cyclohexyl ring and a heterocyclic ring, and an arbitrary hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms. Group, an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom.
n1 is an integer of 0-4.
Y ⁶ is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxyl group having 1 to 18 carbon atoms, or a fluorine-containing alkoxyl group having 1 to 18 carbon atoms. )

(R ²¹ , R ²² and R ²³ are each independently —OCH ₃ , —OC ₂ H ₅ , —OCH (CH ₃ ) ₂ , —OC (CH ₃ ) ₃ , —CH ₃ , —Ph (phenyl group) ), —Cl, —OCOCH ₃ , —OH, or
R ²⁴ is a hydrogen atom or a methyl group.
Y ²¹ is a straight or branched hydrocarbon group having 1 to 8 carbon atoms which may contain a single bond or a double bond.
Y ²² represents a single bond, —O—, —CO—, —COO—, —OCO—, —NH—, —N (CH ₃ ) —, —NPh—, —NHCO—, —N (CH ₃ ) CO—. _{_{_{, -NPhCO -, - NHSO 2 -}}} , - N (CH 3) SO 2 -, - NPhSO 2 -, - S -, - SO 2 -, - NHCONH, -N (CH 3) CONH -, - NPhCONH-, The bonding group is selected from —NHCOO— and —OCONH—.
Y ²³ and Y ²⁴ are each independently a single bond or a linear or branched hydrocarbon group having 1 to 8 carbon atoms.
Y ²⁵ represents a single bond, —O—, or —NZ ₂ —, and Z ₂ represents a hydrogen atom, a linear or branched hydrocarbon group having 1 to 18 carbon atoms, an aromatic ring group, or an aliphatic group. It is a cyclic group.
Cy is an alkyl group or a divalent cyclic group selected from the following and bonded at an arbitrary substitution position. An arbitrary hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, a carbon number It may be substituted with 1 to 3 alkoxy groups, cyano groups, fluorine atoms, or chlorine atoms. )

(Z ₁ is a linear or branched divalent hydrocarbon group having 1 to 18 carbon atoms which may contain an aromatic ring group or an aliphatic ring group.)

(2) The raw material alkoxysilane further contains an alkoxysilane represented by the following formula (5) having a group having a polymerization inhibiting function, and a polymerization inhibiting component ( The liquid crystal aligning agent as described in said (1) in which B) contains.
R ^a Si (OR ^b ) ₃ (5)
(R ^a is a group having a polymerization inhibiting function, and R ^b is an alkyl group having 1 to 5 carbon atoms.)

(3) The liquid crystal aligning agent as described in said (1) in which the polysiloxane formed from the alkoxysilane represented by following formula (5) is contained as a substance different from the said polysiloxane component (A).
R ^a Si (OR ^b ) ₃ (5)
(R ^a is a group having a polymerization inhibiting function, and R ^b is an alkyl group having 1 to 5 carbon atoms.)

(4) The liquid crystal aligning agent as described in said (2) or (3) whose alkoxysilane represented by Formula (5) is the following compound.

(5) The hindered phenol which the polymerization prohibition component (B) contained as a substance different from the polysiloxane component (A) is phenol, catechol, benzoquinone, hydroquinone, or an ester, etherified product or alkylated thereof. Liquid crystal aligning agent as described in said (1) which is phenothiazine, hindered amine, hydroxyamine, or nitrosamine.
(6) The liquid crystal alignment according to any one of (1) to (5), wherein the polymerization-inhibiting component (B) is contained in an amount of 0.01 to 20 mol% with respect to the polysiloxane component (A). Agent.
(7) The raw material alkoxysilane contains 2 to 30 mol% of the alkoxysilane represented by the formula (1) and 5 to 70 mol% of the alkoxysilane represented by the formula (3). The liquid crystal aligning agent according to any one of the above (1) to (6).

(8) The liquid crystal aligning agent according to any one of (1) to (7), wherein the raw material alkoxysilane further contains an alkoxysilane represented by the following formula (4):
R ³ Si (OR ⁴ ) ₃ (4)
(R ³ is an alkyl group having 1 to 30 carbon atoms in which a hydrogen atom is substituted with an acrylic group, acryloxy group, methacryl group, methacryloxy group or styryl group. R ⁴ is an alkyl group having 1 to 5 carbon atoms. is there.)

(9) The liquid crystal aligning agent according to any one of (1) to (7) above, which contains a polysiloxane (C) formed from an alkoxysilane represented by the following formula (6).
Si (OR ¹⁵ ) ₄ (6)
(R ¹⁵ is an alkyl group having 1 to 5 carbon atoms.)

(10) At least one of the polysiloxane component (A) and the polysiloxane (C) is a polysiloxane obtained by reacting an alkoxysilane further containing an alkoxysilane represented by the following formula (7) ( The liquid crystal aligning agent according to any one of 1) to (8).
(R ¹³ ) _n2 Si (OR ¹⁴ ) _4-n (7)
(R ¹³ represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms in which the hydrogen atom 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.
R ¹⁴ is an alkyl group having 1 to 5 carbon atoms, and n2 represents an integer of 0 to 3. )

(11) A liquid crystal alignment film obtained by using the liquid crystal aligning agent according to any one of (1) to (10) above.
(12) A liquid crystal display element comprising the liquid crystal alignment film according to (11).
(13) The liquid crystal alignment film includes a pair of liquid crystal alignment films according to (11) and a liquid crystal layer sandwiched between the liquid crystal alignment films, and the liquid crystal alignment film emits light in a state where a voltage is applied to the liquid crystal layer. The liquid crystal display element according to claim 12, wherein the liquid crystal display element is formed by being irradiated.

By using the liquid crystal aligning agent of the present invention, it is possible to form a liquid crystal alignment film that suppresses the decrease in photoreactivity, controls the alignment of the liquid crystal by light, and further improves the response speed of the liquid crystal. By using the alignment film, a VA mode liquid crystal display element is provided.
That is, in the liquid crystal display element having the liquid crystal alignment film formed from the liquid crystal alignment agent of the present invention, the thermal reaction of the photoreactive side chain of the liquid crystal alignment film is suppressed, and the liquid crystal alignment control and response speed by light are suppressed. Will improve. In addition, the firing margin (Margin) of the liquid crystal alignment film in the manufacturing process of the liquid crystal display element can be increased. Thus, the liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention provides a VA mode liquid crystal display element having excellent response characteristics.

Furthermore, since the polysiloxane component (A) contained in the liquid crystal aligning agent of the present invention is inexpensive compared with the polyimide-based material that has been conventionally used in the liquid crystal aligning film, the liquid crystal aligning agent of the present invention is It can be manufactured at a lower cost than conventional ones and is highly versatile.

<Liquid crystal aligning agent>
The liquid crystal aligning agent of the present invention comprises a polysiloxane component (A) formed from a raw material alkoxysilane containing an alkoxysilane represented by the formula (1) and an alkoxysilane represented by the following formula (3), and polymerization: Contains prohibited component (B).

<Polysiloxane component (A)>
As described above, the polysiloxane component (A) (hereinafter also referred to as polysiloxane (A)) contains an alkoxysilane represented by the following formula (1) and an alkoxysilane represented by the following formula (3). It is a polysiloxane formed from raw material alkoxysilane.

R ¹ Si (OR ² ) ₃ (1)
(R ¹ represents the structure of the following formula (2), and R ² represents an alkyl group having 1 to 5 carbon atoms.)

In the above formula (2), Y ¹ is a single bond, — (CH ₂ ) _a — (a is an integer of 1 to 15), —O—, —CH ₂ O—, —COO— or —OCO—. One of them. Among them, a single bond, — (CH ₂ ) _a — (a is an integer of 1 to 15), —O—, —CH ₂ O— or —COO— can be selected. It is preferable from the viewpoint of facilitating the synthesis of the chain structure. It is more preferable to select any one of a single bond, — (CH ₂ ) _a — (a is an integer of 1 to 10), —O—, —CH ₂ O—, or —COO—.

Y ² is a straight or branched hydrocarbon group having 3 to 8 carbon atoms containing a single bond or a double bond, or — (CR ¹⁷ R ¹⁸ ) _b — (b is an integer of 1 to 15 , R ¹⁷ and R ¹⁸ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Of these, — (CH ₂ ) _b — (b is an integer of 1 to 10) is preferable from the viewpoint of significantly improving the response speed of the liquid crystal display element.

Y ³ is a single bond, — (CH ₂ ) _c — (c is an integer of 1 to 15), —O—, —CH ₂ O—, —COO— or —OCO—. Among them, a single bond, — (CH ₂ ) _c — (c is an integer of 1 to 15), —O—, —CH ₂ O—, —COO— or —OCO— is selected. This is preferable from the viewpoint of facilitating the synthesis of the side chain structure. And a single bond, — (CH ₂ ) _c — (c is an integer of 1 to 10), —O—, —CH ₂ O—, —COO— or —OCO— is selected. Is more preferable.

Y ⁴ is a single bond or a divalent cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring and a heterocyclic ring, and any hydrogen atom on these cyclic groups has 1 to 3 carbon atoms. Or an alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. Furthermore, Y ⁴ may be a divalent organic group selected from organic groups having 12 to 25 carbon atoms having a steroid skeleton. Among these, an organic group having 12 to 25 carbon atoms having any one of a benzene ring, a cyclohexane ring, and a steroid skeleton is preferable.

Y ⁵ is a divalent cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring, and a heterocyclic ring, and any hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, carbon It may be substituted with any one of an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom.
n1 is an integer of 0 to 4, preferably an integer of 0 to 2.

Y ⁶ is an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxyl group having 1 to 18 carbon atoms, or a fluorine-containing alkoxyl group having 1 to 18 carbon atoms. Among these, an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 18 carbon atoms, or a fluorine-containing alkoxyl group having 1 to 10 carbon atoms is preferable. More preferably, it is an alkyl group having 1 to 12 carbon atoms or an alkoxyl group having 1 to 12 carbon atoms. More preferred is an alkyl group having 1 to 9 carbon atoms or an alkoxyl group having 1 to 9 carbon atoms.
R ² in the above formula (1) is an alkyl group having 1 to 5, preferably 1 to 3 carbon atoms. More preferably, R ² is a methyl group or an ethyl group.

Specific examples of the alkoxysilane represented by the above formula (1) include, but are not limited to, the formulas [1-1] to [1-31]. Also, ^{R 2} in the formula [1-1] - [1-31] has the same meaning as ^{R 2} in the formula (1).

(R ⁵ is —O—, —OCH ₂ —, —CH ₂ O—, —COOCH ₂ — or —CH ₂ OCO—, and R ⁶ is an alkyl group having 1 to 22 carbon atoms, an alkoxy group, or a fluorine-containing alkyl group. Group or fluorine-containing alkoxy group.)

(R ⁷ is a single bond, —COO—, —OCO—, —COOCH ₂ —, —CH ₂ OCO—, — (CH ₂ ) _n O— (n is an integer of 1 to 5), —OCH ₂ — or — CH ₂ — and R ⁸ is an alkyl group, alkoxy group, fluorine-containing alkyl group or fluorine-containing alkoxy group having 1 to 22 carbon atoms.)

(R ⁹ is —COO—, —OCO—, —COOCH ₂ —, —CH ₂ OCO—, —CH ₂ O—, —OCH ₂ —, —CH ₂ — or —O—, and R ¹⁰ is a fluorine group , Cyano group, trifluoromethane group, nitro group, azo group, formyl group, acetyl group, acetoxy group or hydroxyl group.)

(R ¹¹ is an alkyl group having 3 to 12 carbon atoms, and the cis-trans isomerism of 1,4-cyclohexylene is a trans isomer.)

(R ¹² is an alkyl group having 3 to 12 carbon atoms, and the cis-trans isomerism of 1,4-cyclohexylene is a trans isomer.)

(B ₄ is an alkyl group having 3 to 20 carbon atoms which may be substituted with a fluorine atom.
B ₃ is a 1,4-cyclohexylene group or a 1,4-phenylene group.
B ₂ is an oxygen atom or —COO— * (where a bond marked with “*” is bonded to B ₃ ).
B ₁ is bonded to an oxygen atom or —COO— * (where a bond marked with “*” is bonded to (CH ₂ ) a ₂ ). ).
A ₁ is an integer of 0 or 1, a ₂ is an integer of 2 to 10, and a ₃ is an integer of 0 or 1. )

The alkoxysilane represented by the above formula (1) is the solubility of the resulting polysiloxane (A) in the solvent, the orientation of the liquid crystal when it is used as a liquid crystal alignment film, the pretilt angle characteristics, the voltage holding ratio, the accumulated charge, etc. Depending on the characteristics, one type or two or more types can be used. Further, it can be used in combination with an alkoxysilane containing a long-chain alkyl group having 10 to 18 carbon atoms.
Such an alkoxysilane represented by the formula (1) can be produced by a known method disclosed in, for example, Japanese Patent Application Laid-Open No. 61-286393.

The alkoxysilane represented by the formula (1) is preferably 1 mol% or more in order to obtain good liquid crystal alignment in all raw material alkoxysilanes used for obtaining the polysiloxane (A). More preferably, it is 1.5 mol% or more. More preferably, it is 3 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.

The liquid crystal alignment film of the liquid crystal aligning agent containing the polysiloxane (A) formed using the alkoxysilane represented by the above formula (3) is tilted and aligned in a desired direction by applying a voltage. After forming the state, the side chain having a cyclic group and a (meth) acryloyl group derived from the alkoxysilane of formula (3) undergoes a polymerization reaction upon receiving light irradiation. By this photopolymerization reaction of the side chain, the tilted alignment state of the liquid crystal by voltage application is fixed, and a very small pretilt angle is formed in the liquid crystal layer sandwiched between the liquid crystal alignment films. Such a substantially vertical alignment state of the liquid crystal with a pretilt angle can realize a high-speed response of the liquid crystal in the VA mode liquid crystal display element of the present invention.

R ²¹ , R ²² and R ²³ in the above formula (3) are each independently —OCH ₃ , —OC ₂ H ₅ , —OCH (CH ₃ ) ₂ , —OC (CH ₃ ) ₃ , —CH ₃ , —Ph (phenyl group, ie, —C ₆ H ₅ ), —Cl, —OCOCH ₃ , —OH, or —H. R ²¹ , R ²² and R ²³ are preferably independently —OCH ₃ or —OC ₂ H ₅ .
R ²⁴ represents a hydrogen atom or a methyl group, and a methyl group is preferable.

Y ²¹ in the above formula (3) is a linear or branched hydrocarbon group having 1 to 8 carbon atoms which may contain a single bond or a double bond. Preferably, Y ²¹ is a single bond or a linear hydrocarbon group having 3 to 5 carbon atoms.

Y ²² in the above formula (3) represents a single bond, —O—, —CO—, —COO—, —OCO—, —NH—, —N (CH ₃ ) —, —NPh—, —NHCO—, — _{_{_{N (CH 3) CO -,}}} - NPhCO -, - NHSO 2 -, - N (CH 3) SO 2 -, - NPhSO 2 -, - S -, - SO 2 -, - NHCONH, -N (CH 3) The bonding group is selected from CONH—, —NPhCONH—, —NHCOO—, and —OCONH—. Y ²² is preferably a single bond.

Y ²³ in the above formula (3) is a single bond or a linear or branched hydrocarbon group having 1 to 8 carbon atoms, and preferably Y ²³ is a single bond.
Y ²⁴ is a single bond or a linear or branched hydrocarbon group having 1 to 8 carbon atoms, and preferably Y ²⁴ is a single bond or a linear hydrocarbon group having 1 to 3 carbon atoms. It is.
Y ²⁵ is a single bond, —O—, or —NZ ₂ —. Here, Z ₂ represents a hydrogen atom, a linear or branched hydrocarbon group having 1 to 18 carbon atoms, an aromatic ring group, or an aliphatic ring group. Preferably, Y ²⁵ is a single bond, —O— or —NH—.

Cy in the above formula (3) represents a divalent cyclic group selected from the following and formed at any substitution position, and any hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms. And may be substituted with an alkoxy group having 1 to 3 carbon atoms, a cyano group, a fluorine atom, or a chlorine atom. Preferably, Cy is a benzene ring or a biphenyl ring. Note that “a divalent cyclic group formed by bonding at an arbitrary substitution position” means that the position of two bonds of the following cyclic group may be arbitrary.

Z ₁ represents a linear or branched divalent hydrocarbon group having 1 to 18 carbon atoms which may contain an aromatic ring group or an aliphatic ring group.

Two or more types of alkoxysilanes represented by the above formula (1) and the above formula (3) may be contained in the raw material alkoxysilane forming the polysiloxane (A).

The blending ratio of the alkoxysilane represented by the above formula (1) and the alkoxysilane represented by the above formula (3) when forming the polysiloxane (A) is not particularly limited. The alkoxysilane represented by the above formula (1) is preferably 2 to 30 mol%, particularly preferably 3 to 25 mol% in the (total) alkoxysilane used as a raw material for obtaining the polysiloxane (A). is there. The alkoxysilane represented by the above formula (3) is preferably 5 to 70 mol%, more preferably 5 to 60 mol% in the raw material alkoxysilane used for obtaining the siloxane (A).

As mentioned above, in addition to the raw material alkoxysilane containing the alkoxysilane represented by the formula (1) and the alkoxysilane represented by the formula (3), the polysiloxane (A) is an alkoxysilane other than these. Such other alkoxysilanes can be formed from an alkoxysilane represented by the following formula (4), and represented by the following formula (5) for introducing a polymerization inhibiting function described later. And / or alkoxysilanes represented by the following formula (7).
R ³ Si (OR ⁴ ) ₃ (4)
R ^a Si (OR ^b ) ₃ (5)
(R ¹³ ) _n2 Si (OR ¹⁴ ) _4-n (7)
(R ³ , R ⁴ , R ^a , R ^b , R ¹³ , and R ¹⁴ are as defined above.)

R ³ in the above formula (4) is an alkyl group in which a hydrogen atom is substituted with an acryl group, an acryloxy group, a methacryl group, a methacryloxy group, or a styryl group. The number of substituted hydrogen atoms is one or more, preferably one. The alkyl group preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and still more preferably 1 to 10 carbon atoms.
R ⁴ in Formula (4) is an alkyl group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, and more preferably 1 to 2 carbon atoms.

Specific examples of the alkoxysilane represented by the above formula (4) are given. For example, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, methacryloxymethyltrimethoxysilane, methacryloxymethyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxy Silane, acryloxyethyltrimethoxysilane, acryloxyethyltriethoxysilane, styrylethyltrimethoxysilane, styrylethyltriethoxysilane, and 3- (N-styrylmethyl-2-aminoethylamino) propyltrimethoxysilane. However, it is not limited to these.

The alkoxysilane represented by the above formula (4) is preferably 5 to 80 mol%, more preferably 10 to 70 mol% in the raw material alkoxysilane used to obtain the polysiloxane (A). Two or more types of alkoxysilanes represented by formula (4) can be used.

The alkoxysilane represented by the following formula (5) used for obtaining the polysiloxane (A) is an alkoxysilane having a polymerization inhibiting function. When the raw material alkoxysilane containing the alkoxysilane of the formula (5) is used, a polysiloxane (A) having a polymerization inhibiting component as a constituent part can be produced.
R ^a Si (OR ^b ) ₃ (5)

R ^a in the formula (5) represents a group having a polymerization inhibiting function, that is, a group having a polymerization inhibitor skeleton similar to a known polymerization inhibitor. R ^b represents an alkyl group having 1 to 5 carbon atoms. Preferred examples of ^Ra include hindered phenols and hydroquinone.

The alkoxysilane represented by the formula (5) is preferably 1 to 20 mol%, more preferably 2 to 15 mol% in the raw material alkoxysilane used for obtaining the polysiloxane (A).

Preferred examples of the alkoxysilane represented by the formula (5) include the following compounds.

In addition, the alkoxysilane represented by the following formula (7) used for obtaining the polysiloxane (A) is improved in adhesion to the substrate of the liquid crystal alignment film of the present invention and affinity for liquid crystal. For the purpose of, it is contained in the raw material alkoxysilane.
Since the alkoxysilane represented by the formula (7) can impart various properties to the polysiloxane, one or more types can be selected and used.
The alkoxysilane represented by the following formula (7) is preferably 1 to 20 mol% in the raw material alkoxysilane used for obtaining the polysiloxane (A).
(R ¹³ ) _n2 Si (OR ¹⁴ ) _4-n (7)

R ¹³ in the above formula (7) is a hydrogen atom or an organic group having 1 to 10 carbon atoms. Examples of R ¹³ include ring structures such as aliphatic hydrocarbons, aliphatic rings, aromatic rings or heterocyclic rings having 1 to 10 carbon atoms, and these include unsaturated bonds, oxygen atoms, nitrogen It may contain heteroatoms such as atoms and sulfur atoms, and may be linear or branched. The number of carbon atoms is preferably 1-6. The hydrogen atom of the hydrocarbon 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.
R ¹⁴ in the formula (7) is an alkyl group having 1 to 5, preferably 1 to 3 carbon atoms, and n2 represents an integer of 0 to 3, preferably 0 to 2.

Specific examples of the alkoxysilane represented by the above formula (7) are given below. For example, 3- (2-aminoethylaminopropyl) trimethoxysilane, 3- (2-aminoethylaminopropyl) triethoxysilane, 2-aminoethylaminomethyltrimethoxysilane, 2- (2-aminoethylthioethyl) Triethoxysilane, 3-mercaptopropyltriethoxysilane, mercaptomethyltrimethoxysilane, vinyltriethoxysilane, 3-isocyanatopropyltriethoxysilane, trifluoropropyltrimethoxysilane, chloropropyltriethoxysilane, bromopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, diethyldiethoxysilane, diethyldimethoxysilane, diphenyldimethoxysilane, diphenyl Diethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyldimethylethoxysilane, trimethylethoxysilane, trimethylmethoxysilane, γ-ureidopropyltriethoxysilane, γ-ureidopropyltrimethoxysilane, γ-ureidopropyltri And propoxysilane. However, it is not limited to these.

In the alkoxysilane represented by the formula (7), the alkoxysilane in which n2 is 0 is tetraalkoxysilane. Tetraalkoxysilane is preferable for obtaining polysiloxane (A) because it easily undergoes a polycondensation reaction with the alkoxysilane represented by the above formula (1), formula (3), formula (4) and formula (5). .

In the formula (7), the alkoxysilane having n2 of 0 is more preferably tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane or tetrabutoxysilane, and particularly preferably tetramethoxysilane or tetraethoxysilane.

In the formula (7), n2 is 1 to 3, and the alkoxysilane represented by the formula (7) is preferably 1 to 20 mol% in the raw material alkoxysilane used for obtaining the polysiloxane (A). Particularly preferred is 1 to 10 mol%. Further, the alkoxysilane represented by the formula (7) in which n2 is 0 is preferably 1 to 50 mol% in the raw material alkoxysilane used for obtaining the polysiloxane (A), and preferably 5 to 40 mol%. More preferred.

<Polymerization inhibition component (B)>
The liquid crystal aligning agent of this invention contains the polymerization prohibition component (B) for suppressing the thermal reaction of the photoreactive side chain of a polysiloxane component (A). The polymerization inhibiting component (B) can introduce a polymerization inhibiting function into the liquid crystal alignment film formed from the liquid crystal aligning agent of the present invention. The polymerization inhibiting component (B) is a compound that retards or inhibits polymerization, and in the present invention, it is a substance that delays or inhibits the thermal reaction of the photoreactive side chain contained in the liquid crystal alignment film. .
As described above, the polymerization inhibiting component (B) can be contained in the liquid crystal aligning agent as a constituent part of the polysiloxane component (A). That is, the polymerization-inhibiting component (B) is used in combination with the alkoxysilane of the above formula (5) for imparting a polymerization-inhibiting function when forming the polysiloxane component (A). To be included.

In the present invention, the polymerization inhibiting component (B) is a component different from the polysiloxane component (A), that is, a liquid crystal aligning agent as a polymerization inhibitor which is a substance different from the polysiloxane component (A). It can be contained in the inside.
As long as such a polymerization inhibitor has the above-described polymerization inhibition function, the molecular structure thereof is not particularly limited.

When the reaction of the photoreactive side chain contained in the liquid crystal alignment film is a radical reaction (?), The polymerization inhibitor should be phenol, catechol, benzoquinone, hydroquinone, their esters, etherified products or alkylated compounds Hindered phenols, phenothiazines, hindered amines, hydroxyamines such as TEMPO (2,2,6,6-tetramethylpiperidine-oxyl), and nitrosamines.
Preferable examples of the polymerization inhibitor include the following compounds.

Further, as the polymerization inhibitor, the alkoxysilane of the formula (5) having the above-described polymerization inhibition function is used as a monomer in the liquid crystal aligning agent or of the formula (5) containing the alkoxysilane of the formula (5). It can be contained as a polysiloxane obtained from alkoxysilane. In this case, the alkoxysilane of the formula (5) functions in the same manner as the polymerization inhibitor described above, or other than, for example, polysiloxane (A) by heating and baking after forming the coating film of the liquid crystal aligning agent. It causes a polymerization reaction with the polysiloxane component, and can impart a polymerization inhibition function to the liquid crystal alignment film.

In the present invention, the content of the polymerization inhibitor in the liquid crystal aligning agent is preferably 0.01 to 20 mol% based on the polysiloxane component (A), including the case where it is derived from the alkoxysilane of the formula (5). 2 to 10 mol% is more preferable.

<Polysiloxane component (C)>
The liquid crystal aligning agent of this invention contains the other polysiloxane component (C) (henceforth also called polysiloxane (C)) other than a polysiloxane component (A) and a polymerization inhibition component (B). Also good.
Examples of the polysiloxane (C) include polysiloxane obtained by reacting a raw material alkoxysilane containing an alkoxysilane represented by the following formula (6).
The polysiloxane that is the raw material of the polysiloxane (C) preferably contains 20 to 100 mol%, more preferably 50 to 100%, of the alkoxysilane represented by the formula (6).
Si (OR ¹⁵ ) ₄ (6)
However, in the above formula (6), R ¹⁵ represents an alkyl group having 1 to 5 carbon atoms.

As the alkoxysilane represented by the above formula (6), tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane or tetrabutoxysilane is preferable, and tetramethoxysilane or tetraethoxysilane is particularly preferable.

The polysiloxane (C) is a polysiloxane obtained by reacting an alkoxysilane containing the alkoxysilane represented by the formula (8) in addition to the alkoxysilane represented by the formula (6). Also good.
A liquid crystal aligning agent containing a polysiloxane (C) obtained by reacting an alkoxysilane containing an alkoxysilane represented by the formula (8) is preferable because a liquid crystal alignment film having a particularly high vertical alignment force can be formed.
R ¹⁶ Si (OR ¹⁷ ) ₃ (8)
R ¹⁶ in the above formula (8) is an alkyl group having 1 to 5 carbon atoms. The alkyl group preferably has 1 to 4 carbon atoms, more preferably 1 to 3 carbon atoms.

R ¹⁷ in the formula (8) is an alkyl group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, and particularly preferably 1 to 2 carbon atoms.
Specific examples of the alkoxysilane represented by the formula (8) include methyltriethoxysilane, methyltrimethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane and the like. However, it is not limited to these.

The polysiloxane (C) is a polysiloxane obtained by reacting an alkoxysilane containing the alkoxysilane represented by the formula (4) in addition to the alkoxysilane represented by the formula (6). There may be.

In the polysiloxane (C), the content of the alkoxysilane represented by the formula (4) realizes the vertical alignment state of the liquid crystal desired by the liquid crystal alignment film of the present invention and further improves the response speed of the liquid crystal. A suitable amount is preferred. That is, the content of the alkoxysilane represented by the formula (4) is preferably 10 mol% or more, more preferably 20 mol% or more, particularly preferably 30 mol% or more in the raw material alkoxysilane of the polysiloxane (C). It is. Moreover, in order to fully harden the liquid crystal aligning film formed, 75 mol% or less is preferable.

The polysiloxane (C) is a polysiloxane obtained by reacting an alkoxysilane containing the alkoxysilane represented by the formula (5) in addition to the alkoxysilane represented by the formula (6). Also good.
Further, the polysiloxane (C) is further expressed by the above formula (7) unless the effects of the present invention are impaired for the purpose of imparting various properties such as adhesion to the substrate and improvement in affinity with the liquid crystal. Polysiloxane obtained by reacting the alkoxysilane represented may be used.

The content of the alkoxysilane represented by the formula (7) is preferably 1 to 20 mol%, more preferably 1 to 10 mol% in the raw material alkoxysilane of the polysiloxane (C). When used as a raw material for the polysiloxane (C), the alkoxysilanes represented by the above formula (4), formula (5), formula (6), formula (7), and formula (8) are all two types. That's all.

The blending ratio of the polysiloxane in the liquid crystal aligning agent containing the polysiloxane component (A) and other polysiloxane such as the polysiloxane component (C) is not particularly limited, but the total amount of polysiloxane contained in the liquid crystal aligning agent is not limited. On the other hand, the polysiloxane component (A) is preferably 10% by mass or more, and more preferably 50 to 90% by mass. The polysiloxane component (C) and the like are preferably in a mass ratio of polysiloxane component (A): polysiloxane component (C) = 10: 90 to 50:50, and 50:50 to 90:10. More preferred.

<Method for producing polysiloxane>
The method for obtaining the polysiloxane component (A) and the polymerization inhibiting component (C) as the components of the liquid crystal aligning agent of the present invention is not particularly limited, and alkoxysilane may be reacted.
For example, in the production of the polysiloxane component (A), an alkoxysilane containing the alkoxysilane represented by the above formula (1) and the alkoxysilane represented by the above formula (3) is reacted (heavy) in an organic solvent. (Condensation reaction). Usually, polysiloxane is obtained as a solution obtained by polycondensation of such alkoxysilanes and uniformly dissolved in an organic solvent.

Moreover, as an alkoxysilane used for formation of polysiloxane (A), together with the alkoxysilane represented by the above formula (1) and the above formula (3), for example, the alkoxysilane represented by the above formula (4), the above When producing the polysiloxane (A) using the alkoxysilane represented by (5) and / or the alkoxysilane represented by (7), the alkoxysilane can be reacted in the same manner as described above. .

As a specific method for polycondensation of alkoxysilane to obtain polysiloxane such as polysiloxane (A), for example, a method of hydrolyzing and condensing contained alkoxysilane in a solvent such as alcohol or glycol can be mentioned. . 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-mentioned reaction can be appropriately selected as desired, but it is usually 0.5 to 2.5 times mol of all alkoxy groups in the alkoxysilane contained in the alkoxysilane. It is preferably 0.5 to 2 moles.

In addition, for the purpose of promoting hydrolysis / condensation reaction of alkoxysilane, acid such as hydrochloric acid, sulfuric acid, nitric acid, acetic acid, formic acid, succinic acid, maleic acid, fumaric acid, ammonia, methylamine, ethylamine, ethanolamine, triethylamine, etc. Catalysts such as alkali, hydrochloric acid, sulfuric acid, nitric acid and other metal salts can be used. 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, in addition to the method of heating and stirring at 50 ° C. for 24 hours, the method of heating and stirring for 1 hour under reflux can be mentioned.

Furthermore, 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 this case, the amount of succinic acid used is preferably 0.2 to 2 mol, more preferably 0.5 to 2 mol, based on 1 mol of all alkoxy groups contained in the alkoxysilane contained in the alkoxysilane. Heating in this method can be performed at a liquid temperature of 50 ° C. to 180 ° C. A method of heating for several tens of minutes to several tens of hours under reflux is preferred so that evaporation or volatilization of volatile components such as solvents does not occur.

In the present invention, when the polysiloxane is obtained, a plurality of alkoxysilanes are used as the raw material alkoxysilane. However, each alkoxysilane may be mixed in advance as a mixture, or a plurality of alkoxysilanes may be sequentially added. You may mix. That is, there is no limitation on the order of reacting alkoxysilane, for example, alkoxysilane may be reacted at once,

Further, after reacting some alkoxysilanes, other alkoxysilanes may be added and reacted. Specifically, for example, in order to form polysiloxane (A), the alkoxysilane represented by the above formula (1), the alkoxysilane represented by the above formula (3), and the above formula (4) are represented. May be mixed with each other to cause a polycondensation reaction. The alkoxysilane represented by the above formula (1) and the alkoxysilane represented by the above formula (4) may be subjected to a polycondensation reaction. You may make it react by adding the alkoxysilane represented by (3).

Similarly, for example, in order to form polysiloxane (A), alkoxysilane represented by the above formula (1), alkoxysilane represented by the above formula (3), and alkoxy represented by the above formula (5) Silane may be mixed and subjected to a polycondensation reaction. After a polycondensation reaction between the alkoxysilane represented by the above formula (1) and the alkoxysilane represented by the above formula (5), the above formula (3 ) May be added and reacted.

The solvent used for polycondensation of the raw material alkoxysilane (hereinafter also referred to as polymerization solvent) is not particularly limited as long as it dissolves the alkoxysilane. Moreover, even when alkoxysilane does not melt | dissolve, what melt | dissolves as the polycondensation reaction of alkoxysilane progresses is sufficient. 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, 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 obtained by the above method (hereinafter also referred to as polymerization solution) is a concentration obtained by converting silicon atoms of all raw material alkoxysilanes charged as raw materials into SiO ₂ (hereinafter referred to as SiO ₂ conversion concentration). .) Is preferably 20% by mass or less, 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.

<Other ingredients>
In the liquid crystal aligning agent of the present invention, in addition to the polysiloxane component (A) and the polymerization inhibiting component (B), other components, for example, inorganic fine particles, metalloxane oligomers, metalloxanes, as long as the effects of the present invention are not impaired. Components such as a polymer, a leveling agent and a surfactant may be contained.

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 liquid crystal aligning agent of this invention, it becomes possible to provide the surface shape of the cured film (liquid crystal aligning film) formed, and other functions by containing inorganic fine particles.
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 inorganic fine particles include water and organic solvents. As the colloidal solution, it is preferable that the pH or pKa is adjusted to 1 to 10 from the viewpoint of the stability of the coating solution 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. Among these, alcohols and ketones are preferable. These organic solvents can be used alone or in combination of two or more as a dispersion medium.

As the metalloxane oligomer and metalloxane polymer that can be used as other optional components, 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 commercial 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 siloxane polymers and titanoxane oligomers such as titanium-n-butoxide tetramer manufactured by Kanto Chemical Co., Inc. You may use these individually or in mixture of 2 or more types.

As other optional components, known leveling agents, surfactants, and the like can be used, and commercially available products are particularly preferable because they are easily available.
Moreover, in the liquid crystal aligning agent of this invention, the method of adding the other arbitrary component mentioned above may be simultaneous with polysiloxane (A), or after that, and is not specifically limited.

<Preparation of liquid crystal aligning agent>
The liquid crystal aligning agent of this invention is a liquid containing a polysiloxane component (C) and other components as needed in addition to the above-mentioned polysiloxane component (A) and polymerization inhibiting component (B). In the liquid crystal aligning agent of this invention, it is preferable that each said component is mixed uniformly.

For example, a polymerization inhibitor may be added to a reaction solution such as a polysiloxane polymerization solution obtained by the above method to form a liquid crystal aligning agent, or a reaction solution such as a polysiloxane polymerization solution obtained by the above method may be used. If necessary, it may be concentrated, diluted by adding a solvent, or substituted with another solvent, and a polymerization inhibitor may be added thereto to form a liquid crystal aligning agent. In this case, as the solvent, a solvent selected from the group consisting of the above-mentioned polysiloxane polymerization solvent and additive solvent can be used.

The solvent in the liquid crystal aligning agent is not particularly limited as long as the polysiloxane component (A) and the polymerization inhibiting component (B) are preferably uniformly dissolved, and one or a plurality of types can be arbitrarily selected and used. .
Specific examples of such a solvent include ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, and esters such as methyl acetate, ethyl acetate, and ethyl lactate. 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.

The content of polysiloxane including polysiloxane (A) 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 concentration. In the case of 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 easily obtained.
Moreover, content of polysiloxane in a liquid crystal aligning agent can be adjusted by using the solvent chosen from the group which consists of the polymerization solvent of the polysiloxane mentioned above, and the solvent to add.

<Liquid crystal alignment film>
Since the liquid crystal aligning agent of this invention contains the polysiloxane component (A) and polymerization inhibition component (B) which were mentioned above, the liquid crystal aligning film obtained suppresses the reaction before the light irradiation of the side chain to contain, light The decrease in reactivity can be suppressed, and the alignment control of liquid crystal by light and the improvement of response speed can be realized.

In the present invention, for example, after the liquid crystal aligning agent of the present invention is applied to a substrate to form a coating film, the cured film obtained by drying, if necessary, heating and baking is then used. It can also be used as a liquid crystal alignment film.
In addition, the cured film can be used by orientation treatment, specifically, rubbing, irradiation with polarized light or light having a specific wavelength, treatment with an ion beam, or the like.
Further, in the liquid crystal display element after filling with liquid crystal, for example, UV or other light is irradiated in a state where a voltage is applied to the liquid crystal layer sandwiched between the liquid crystal alignment films, thereby realizing desired alignment control of the liquid crystal.

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. And a plastic plate such as triacetyl cellulose, diacetyl cellulose, and acetate butyrate cellulose, and a substrate on which a transparent electrode is formed.

Examples of the method for applying the liquid crystal aligning agent include spin coating, printing, ink jet, spraying, roll coating, and the like. From the viewpoint of productivity, the transfer printing method is widely used industrially. The present invention is also preferably used.

The step of drying the coating film 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 it is not baked immediately after coating, it is dried. It is preferable to include a process. 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 to 150 ° C., preferably 60 to 100 ° C. for 0.5 to 30 minutes, preferably 1 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 calcination temperature is usually 100 to 350 ° C., preferably 140 to 300 ° C., more preferably 150 to 230 ° C., and further preferably 160 to 220 ° C. The firing time is usually 5 to 240 minutes. The time is preferably 10 to 90 minutes, more preferably 20 to 80 minutes. The heating can be usually performed using a known method, for example, a hot plate, a hot air circulation oven, an IR oven, a belt furnace or the like.

The polysiloxane derived from the polysiloxane component (A) or the like in the liquid crystal alignment film usually undergoes further polycondensation in the heating and firing steps. However, in the present invention, it is not necessary to realize complete polycondensation unless the effects of the present invention are impaired. However, for example, firing is performed at a temperature higher by 10 ° C. or more than the curing temperature of the sealing agent so as not to be affected by heating in a heat treatment process such as curing of the sealing agent required in the manufacturing process of the liquid crystal display element. It is preferable.

The thickness of the liquid crystal alignment film obtained as the cured film can be selected as necessary, but is preferably 5 nm or more, more preferably 10 nm or more. When the film thickness is 10 μm or more, it is preferable because the reliability of the liquid crystal display element can be easily obtained. The thickness of the liquid crystal alignment film is preferably 300 nm or less, more preferably 150 nm or less. A film thickness of 150 nm or less is preferable because 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 has a pair of liquid crystal alignment films of the present invention and a liquid crystal layer sandwiched between the liquid crystal alignment films. In the present invention, the liquid crystal alignment film is preferably formed by being irradiated with light while a voltage is applied to the liquid crystal layer.

The liquid crystal display element of the present invention can be produced by appropriately using a known method after forming a liquid crystal alignment film on a substrate by the method described above.
As an example of a method for manufacturing a liquid crystal display element, a method in which a pair of substrates on which a liquid crystal alignment film of the present invention is formed is fixed with a sealant with a spacer interposed therebetween, and liquid crystal is injected and sealed is preferable. In this case, the size of the spacer to be used is usually 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 the liquid crystal after reducing the pressure inside the manufactured liquid crystal cell, and a dropping method for sealing after dropping the liquid crystal.
After obtaining a liquid crystal display element in which the liquid crystal is introduced and the liquid crystal layer is sandwiched between the pair of liquid crystal alignment films, the liquid crystal display element is irradiated with, for example, UV light. This light irradiation is performed in a state where a voltage is applied between the electrodes on both side substrates sandwiching the liquid crystal layer, that is, in a state where the liquid crystal is inclined and oriented in a uniform direction.

In the production of the liquid crystal display element of the present invention, a photoreaction having, for example, an acryl group or a methacryl group in the liquid crystal alignment film by irradiating UV with a voltage applied between the electrodes on both substrates. For example, a polymerization reaction is carried out in a state where the hydrophilic side chain is in contact with the tilted liquid crystal. By such side chain polymerization, the liquid crystal alignment film is partially cross-linked while interacting with the liquid crystal in the vicinity. As a result, in the liquid crystal display element, the liquid crystal forms a pretilt angle in a predetermined direction and is substantially vertically aligned. The desired liquid crystal alignment state is formed.
In the liquid crystal display element of the present invention, a desired very small pretilt angle is formed in a part of the liquid crystal layer, and the response speed of the liquid crystal is improved.

Here, the voltage applied between the electrodes is 5 to 50 V _pp , but preferably 5 to 30 V _pp . When UV is used for light, the amount of light irradiation is 1 to 60 J, preferably 40 J or less. A smaller amount of light irradiation can suppress a decrease in reliability due to light deterioration of the members constituting the liquid crystal display and can reduce a light irradiation time, so that a manufacturing tact can be improved.

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. Specifically, it is the same as the substrate described above. In this invention, it is also possible to use the board | substrate with which electrode patterns and protrusion patterns, such as conventionally well-known PVA and MVA, were formed.
In addition, the liquid crystal display element of the present invention has a structure in which a line / slit electrode pattern of 1 to 10 μm is formed on one side substrate, and a slit pattern or a projection pattern is not formed on the opposite substrate, like the PSA type liquid crystal display. This simple structure can simplify the manufacturing process and obtain a high transmittance.

In a high-performance liquid crystal display element such as an active matrix liquid crystal display element, a transistor element (thin film transistor (TFT)) 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 light-transmitting substrate as described above. However, in a reflective liquid crystal display element, such as aluminum that reflects light only on one substrate. A material can also be used, and an opaque substrate such as a silicon wafer can also be used.
The liquid crystal display element having the liquid crystal alignment film of the present invention is excellent in response characteristics and display quality, and can be suitably used for a large-screen liquid crystal television or the like.

Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not construed as being limited to these. The main compounds used in the synthesis examples, examples, and the abbreviations thereof are as follows.

(Raw material alkoxysilane)
TEOS: Tetraethoxysilane MPMS: 3-Methacryloxypropyltrimethoxysilane VTMS: Trimethoxyvinylsilane GPS: γ-Glycidoxypropyltrimethoxysilane
UPS: 3-ureidopropyltriethoxysilane SMA: compound represented by the following formula

(Polymerization inhibitor)
SMB: Compound represented by the following formula

3BHT: 2,4,6-tris (3′5′-di-t-butyl-4′-hydroxybenzyl) mesitylene

(solvent)
HG: 2-methyl-2,4-pentanediol (also known as hexylene glycol)
BCS: 2-Butoxyethanol PB: Propylene glycol monobutyl ether

(Synthesis of Compound 2)
A 300 ml four-necked flask equipped with a magnetic stirrer was charged with compound 1 (11.86 g) and toluene (118.60 g), and thionyl chloride (11.27 g) was added with stirring at 50 ° C. for 3 hours. did. Next, toluene and thionyl chloride were distilled off from the reaction solution by concentration under reduced pressure, hexane (20.08 g) was added at room temperature, and the mixture was stirred for 1 hour. Subsequently, the precipitated crystals were subjected to suction filtration under reduced pressure, and then dried under reduced pressure to obtain Compound 2 (8.98 g) (yield: 71%, property: pale yellow solid).
¹ H-NMR (400 MHz) in CDCl ₃ : 1.47 ppm (s, 18H), 5.97 ppm (s, 1H), 7.98 ppm (s, 2H)

(Synthesis of Compound 3)
A 100 ml four-necked flask equipped with a magnetic stirrer was charged with compound 2 (3.00 g) and toluene (30.00 g), and stirred in an ice bath (5 ° C.) with aminopropyltrimethoxysilane (2.21 g). ) Was added dropwise in toluene (12.00 g). Further, triethylamine (1.24 g) was added dropwise and stirred for 3 hours. Next, after adding ethyl acetate (120 g) into the reaction solution, the organic phase was washed three times with pure water (120 g). Further, the organic phase was dehydrated with sodium sulfate and then concentrated and dried to obtain Compound 3 (3.97 g) (yield: 87%, property: yellow oil).
¹ H-NMR (400 MHz) in CDCl ₃ : 0.70-0.75 ppm (m, 2H), 1.46 ppm (s, 18H), 1.71-1.77 ppm (m, 2H), 3.44 ppm (q, J = 6.4 Hz, 2H ), 3.57ppm (s, 9H), 5.53ppm (s, 1H), 6.23-6.32ppm (m, 1H), 7.60ppm (s, 2H)

(Synthesis of Compound 5)
Compound 4 (31.64 g) and toluene (316.4 g) were charged into a 500 ml four-necked flask equipped with a magnetic stirrer, and thionyl chloride (31.85 g) was added with stirring at 60 ° C. for 2 hours. did. Next, toluene and thionyl chloride were distilled off from the reaction solution by concentration under reduced pressure to obtain Compound 5 (34.09 g) (yield: 100%, property: orange oil).
¹ H-NMR (400 MHz) in CDCl ₃ : 1.44 ppm (s, 18H), 4.56 ppm (s, 2H), 5.29 ppm (s, 1H), 7.19 ppm (s, 2H)

(Synthesis of Compound 6)
Compound 5 (34.09 g) and acetonitrile (204.54 g) were charged into a 500 ml four-necked flask equipped with a magnetic stirrer, and mercaptopropyltrimethoxysilane (26.27 g) was stirred in an ice bath (5 ° C.). ) Was added dropwise. Further, triethylamine (14.22 g) was added dropwise and stirred for 2 hours. Next, the salt precipitated in the reaction solution was suction filtered under reduced pressure, ethyl acetate (200 g) was added to the filtrate, and then the organic phase was washed three times with pure water (200 g). Further, the organic phase was dehydrated with sodium sulfate and then concentrated and dried to obtain a crude product (55.43 g) of compound 6 (crude yield: 100%, property: red oil). Subsequently, this crude product (15.06 g) was charged into a Kugelrohr and distilled under reduced pressure at an external temperature of 215 to 240 ° C. and a pressure of 0.6 torr to obtain Compound 6 (6.11 g) ( Yield: 41%, property: yellow oil).
¹ H-NMR (400 MHz) in CDCl ₃ : 0.71-0.76 ppm (m, 2H), 1.43 ppm (s, 18H), 1.65-1.74 ppm (m, 2H), 2.46-2.51 ppm (m, 2H), 3.56 ppm (s, 9H), 3.65ppm (s, 2H), 5.13ppm (s, 1H), 7.09ppm (s, 2H)

<Synthesis Example 1>
In a 100 mL four-necked reaction flask equipped with a thermometer and reflux tube, 8.10 g of HG, 2.70 g of BCS, 5.21 g of TEOS, 3.75 g of SMA, 1.24 g of VTMS and MPMS Was mixed to prepare a raw material alkoxysilane monomer solution. A solution prepared by previously mixing 4.05 g of HG, 1.35 g of BCS, 4.5 g of water, and 0.6 g of oxalic acid as a catalyst was added dropwise to this solution over 30 minutes at room temperature, and further 30 at room temperature. Stir for minutes. Then, after heating using an oil bath and refluxing for 30 minutes, a mixed solution of 0.24 g of a methanol solution having a UPS content of 92% by mass, 0.14 g of HG, and 0.05 g of BCS was added in advance. . Further, the mixture was refluxed for 30 minutes and then allowed to cool to obtain a polysiloxane solution having a SiO ₂ equivalent concentration of 12% by weight.
41.7 g of the obtained polysiloxane solution, 25.12 g of HG, 14.58 g of BCS, and 18.63 g of PB were mixed to obtain a liquid crystal aligning agent [S1] having a SiO ₂ equivalent concentration of 5% by weight. It was.

In 20 g of the obtained liquid crystal aligning agent [S1], 0.31 g of 3BHT (5 mol% with respect to MPMS) was dissolved to obtain a liquid crystal aligning agent [S2]. Incidentally, 3BHT is a polymerization inhibitor component added to the liquid crystal aligning agent [S2] as a polymerization inhibitor. In addition to 3BHT, no polymerization inhibiting component is added to the liquid crystal aligning agent [S1].
Next, in a 50 mL four-necked reaction flask equipped with a thermometer and a reflux tube, 17 g of the liquid crystal aligning agent [S1], 0.34 g of SMB in advance, 0.33 g of HG, and 0. A solution of 17 g and 0.17 g of PB dissolved in 0.38 g (5 mol% with respect to MPMS) was mixed, heated to 60 ° C. in an oil bath and stirred for 15 minutes, then allowed to cool, and SiO 2 A liquid crystal aligning agent [S3] having a ₂ equivalent concentration of 5% by weight was obtained. The SMB used here is a polymerization inhibiting component added to the liquid crystal aligning agent [S3] as a polymerization inhibitor.

<Synthesis Example 2>
In a 100 mL four-necked reaction flask equipped with a thermometer and reflux tube, 8.10 g of HG, 2.70 g of BCS, 5.21 g of TEOS, 3.75 g of SMA, 1.24 g of VTMS and MPMS Was mixed to prepare a raw material alkoxysilane monomer solution. A solution prepared by previously mixing 4.05 g of HG, 1.35 g of BCS, 4.5 g of water, and 0.6 g of oxalic acid as a catalyst was added dropwise to this solution over 30 minutes at room temperature, and further 30 at room temperature. Stir for minutes. Then, after heating using an oil bath and refluxing for 30 minutes, a mixed solution of 0.24 g of a methanol solution having a UPS content of 92% by mass, 0.14 g of HG, and 0.05 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.

41.7 g of the obtained polysiloxane solution, 25.12 g of HG, 14.58 g of BCS, and 18.63 g of PB were mixed to obtain a liquid crystal aligning agent [S4] having a SiO ₂ equivalent concentration of 5 wt%. It was.
In 10.80 g of the obtained liquid crystal aligning agent [S4], 0.16 g of 3BHT (5 mol% with respect to MPMS) was dissolved to obtain a liquid crystal aligning agent [S5].

Next, in a 50 mL four-necked reaction flask equipped with a thermometer and a reflux tube, 17 g of the liquid crystal aligning agent [S4], 0.34 g of SMB in advance, 0.33 g of HG, and 0. A solution of 17 g and 0.17 g of PB dissolved in 0.38 g (5 mol% with respect to MPMS) was mixed, heated to 60 ° C. in an oil bath, stirred for 15 minutes, then allowed to cool, A liquid crystal aligning agent [S6] having a SiO ₂ equivalent concentration of 5% by weight was obtained.

Next, in a 100 mL four-necked reaction flask equipped with a thermometer and a reflux tube, 9.67 g of HG, 3.22 g of BCS, 16.84 g of TEOS, and 0.68 g of SMA were mixed. A solution of raw material alkoxysilane monomer was prepared. To this solution, a solution prepared by previously mixing 4.83 g of HG, 1.61 g of BCS, 4.5 g of water, and 0.08 g of oxalic acid as a catalyst was added dropwise over 30 minutes at room temperature. Stir for minutes. Then, after heating using an oil bath and refluxing for 30 minutes, a mixed solution of 0.24 g of a methanol solution having a UPS content of 92% by mass, 0.14 g of HG, and 0.05 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.

41.7 g of the obtained polysiloxane solution, 24.33 g of HG, 14.58 g of BCS, and 19.42 g of PB were mixed to obtain a liquid crystal aligning agent [U1] having a SiO ₂ equivalent concentration of 5% by weight. It was.

Next, in a 100 mL four-necked reaction flask equipped with a thermometer and a reflux tube, 90 g of the liquid crystal aligning agent [U1], 19.69 g of GPS in advance, 40.15 g of HG, and 20.15 in BCS. 10 g of a solution dissolved in 08 g and 20.08 g of PB (10 mol% based on the total SiO ₂ concentration) was heated to 60 ° C. in an oil bath, stirred for 15 minutes, and then allowed to cool. Thus, a liquid crystal aligning agent [U2] having a SiO ₂ equivalent concentration of 5% by weight was obtained.

Next, 3.24 g of the liquid crystal aligning agent [S4] as the first component, 7.56 g of the liquid crystal aligning agent [U2] as the second component, 3.2 g of HG, 1.07 g of BCS, and 4.B of PB. The liquid crystal aligning agent [L1] was obtained by mixing 93g.
Further, the liquid crystal aligning agent [S5] is 3.24 g as the first component, the liquid crystal aligning agent [U2] is 7.56 g as the second component, HG is 3.2 g, BCS is 1.07 g, and PB is 4.93 g. The liquid crystal aligning agent [L2] was obtained by mixing.

The liquid crystal aligning agent [S6] is 3.24 g as the first component, the liquid crystal aligning agent [U2] is 7.56 g as the second component, HG is 3.2 g, BCS is 1.07 g, and PB is 4.4 g. The liquid crystal aligning agent [L3] was obtained by mixing 93g. The liquid crystal aligning agent [L3] is a liquid crystal aligning agent containing SMB as a polymerization inhibiting component separately from other polysiloxane components.

<Synthesis Example 3>
In a 100 mL four-necked reaction flask equipped with a thermometer and a reflux tube, 8.03 g of HG, 2.68 g of BCS, 5.48 g of TEOS, 4.09 g of SMA, 1.24 g of VTMS, MPMS Was mixed with 9.32 g of SMB and 0.15 g of SMB (1 mol% with respect to MPMS) to prepare a raw material alkoxysilane monomer solution. To this solution, a solution in which 4.01 g of HG, 1.34 g of BCS, 4.5 g of water, and 0.6 g of oxalic acid as a catalyst were added dropwise over 30 minutes at room temperature, and further 30 minutes at room temperature. Stir for minutes. Then, after heating using an oil bath and refluxing for 30 minutes, a mixed solution of 0.24 g of a methanol solution having a UPS content of 92% by mass, 0.14 g of HG, and 0.05 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.

Note that SMB is an alkoxysilane monomer added to form a polymerization-inhibiting component as a part of polysiloxane constituting the liquid crystal alignment film. The polysiloxane in the obtained polysiloxane solution is formed by copolymerization of SMB with another alkoxysilane monomer.
41.7 g of the obtained polysiloxane solution, 25.15 g of HG, 14.58 g of BCS, and 18.6 g of PB were mixed to obtain a liquid crystal aligning agent [S7] having a SiO ₂ equivalent concentration of 5% by weight. .

Next, 3.24 g of the obtained liquid crystal aligning agent [S7] as the first component, 7.56 g of the liquid crystal aligning agent [U2] as the second component, 3.2 g of HG, 1.07 g of BCS, and PB Was mixed to obtain a liquid crystal aligning agent [L4].

<Example 1>
The liquid crystal aligning agent [S2] obtained in Synthesis Example 1 was spin-coated at 1500 rpm on a Cr substrate having a size of 30 mm × 30 mm, temporarily dried on an 80 ° C. hot plate for 90 seconds, and then heated at 200 ° C. in a hot air circulation oven The main baking was performed for 30 minutes to form a liquid crystal alignment film. IR (ATR (attenuated total reflection)) measurement is performed on the obtained liquid crystal alignment film, and the residual ratio of C = C bonds in the liquid crystal alignment film (hereinafter referred to as C = C residual ratio) is obtained from the obtained spectrum. Calculated. The results are shown in Table 1.
The C = C residual ratio was calculated by the following method.

[Calculation of C = C residual ratio]
Resolution 4.0, than the IR spectrum at scan number 64 times the conditions, based on the peak intensity derived from Ph (phenyl group) in the vicinity of 1511cm ^-1, a peak intensity derived from the C = C bond at around 1633 cm ^-1 The ratio (C = C peak intensity ratio) was calculated. The C = C peak intensity ratio (denoted as “after provisional drying” in Table 1 to be described later) of the coating film that was only temporarily dried was 100, and the residual ratio of C = C in the liquid crystal alignment film after the main baking. (In Table 1 to be described later, it is described as “after main firing”).

<Example 2>
Except that the liquid crystal aligning agent [S2] is changed to the liquid crystal aligning agent [S3], a liquid crystal aligning film is prepared in the same manner as in Example 1, ATR measurement is performed, and the residual ratio of C = C is calculated. It is shown in Table 1.

<Comparative Example 1>
Except that the liquid crystal aligning agent [S2] is changed to the liquid crystal aligning agent [S1], a liquid crystal aligning film is prepared in the same manner as in Example 1, ATR measurement is performed, and the residual ratio of C = C is calculated. It is shown in Table 1.

As shown in Table 1, in the liquid crystal alignment film of Comparative Example 1 in which no polymerization inhibiting component was introduced, the residual ratio of C = C after the main baking was 25%, and there was very little C = C in the liquid crystal alignment film. It can be seen that only the C bond remains. On the other hand, in the liquid crystal alignment films of Example 1 and Example 2 in which the polymerization inhibiting component was introduced, the residual ratio of C = C after the main baking was 80% or more, and a large amount of C = C remained in the liquid crystal alignment film. is doing. Therefore, it was found that by introducing a polymerization-inhibiting component into the liquid crystal aligning agent, polymerization (disappearance) of the C═C bond of the liquid crystal alignment film during firing can be suppressed.

<Example 3>
Using the liquid crystal aligning agent [L2] obtained in Synthesis Example 2, spin coating was performed 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. Next, after temporary drying for 90 seconds on a hot plate at 80 ° C., main baking was performed for 30 minutes in a hot air circulation oven at 200 ° C. to form a liquid crystal alignment film having a thickness of 100 nm.

Next, using the liquid crystal aligning agent [L2] obtained in Synthesis Example 2, spin coating was performed on the ITO surface of the ITO electrode substrate having a solid ITO electrode on which no electrode pattern was formed. Next, after temporarily drying on an 80 ° C. hot plate for 90 seconds, as in the case of the ITO electrode substrate on which the ITO electrode pattern is formed, main baking is performed for 30 minutes in a hot air circulation oven at 200 ° C. A 100 nm liquid crystal alignment film was formed. Using these two substrates, 4 μm bead spacers were dispersed on the liquid crystal alignment film surface of one of the substrates, and then a sealant was printed thereon. Next, the liquid crystal alignment film surface of the other substrate was placed inside and bonded together, and then the sealing agent (manufactured by Mitsui Chemicals) was cured to produce an empty cell. Next, liquid crystal MLC-6608 (manufactured by Merck & Co., Inc.) was injected into the produced empty cell by a reduced pressure injection method to produce a liquid crystal cell. The obtained liquid crystal cell was annealed in a circulation oven at 110 ° C. for 15 minutes.

Next, an AC voltage of 30 V _pp was applied to the annealed liquid crystal cell, and 5 J of UV (wavelength: 365 nm) was irradiated from the outside of the liquid crystal cell while the AC voltage was applied.
After that, using a liquid crystal cell irradiated with UV, it was sandwiched between a pair of polarizing plates arranged in a crossed Nicol state and observed under a microscope, and the occurrence of domains, which was a disorder in the alignment of liquid crystals, was observed. Also in the examples, there was very little occurrence of domains, and good orientation was shown. In addition, a VA mode liquid crystal display element was manufactured by using a liquid crystal cell irradiated with UV and sandwiching it between a pair of polarizing plates arranged in crossed Nicols. Using the liquid crystal display element, the response speed of the liquid crystal was measured. Next, the voltage holding ratio of the liquid crystal display element was measured. These evaluation results are summarized in Table 2.

Table 2 shows the type of the liquid crystal aligning agent used in this example as [L2], and also shows the type of the liquid crystal aligning agent of the first component used for the preparation of the liquid crystal aligning agent [L2]. [S5] is shown, and the type of the liquid crystal aligning agent of the second component is shown as [U2]. Furthermore, the polymerization inhibiting component contained in the used liquid crystal aligning agent [L2] was shown, and the main baking temperature and baking time for forming the liquid crystal alignment film were also shown.

The response speed was measured by the following method.
[Response speed measurement]
A 10 V AC voltage and a rectangular wave with a frequency of 1 kHz were applied to the liquid crystal display element, and the time change of the luminance of the liquid crystal display element at that time was captured with an oscilloscope. When the voltage was not applied, the luminance was 0%, a voltage of 10 V was applied, the saturated luminance value was 100%, and the time for the luminance to change from 10% to 90% was evaluated as the rising response speed.

<Example 4>
A liquid crystal cell was produced in the same manner as in Example 3 except that the liquid crystal aligning agent [L2] was changed to the liquid crystal aligning agent [L3], and a VA mode liquid crystal display element was produced.

<Example 5>
A liquid crystal cell was produced in the same manner as in Example 3 except that the liquid crystal aligning agent [L2] was changed to the liquid crystal aligning agent [L4], and a VA mode liquid crystal display element was produced.

<Comparative Example 2>
A liquid crystal cell was produced in the same manner as in Example 3 except that the liquid crystal aligning agent [L2] was changed to the liquid crystal aligning agent [L1], and a VA mode liquid crystal display device was produced.

<Example 6>
A liquid crystal cell was produced in the same manner as in Example 3 except that the conditions for the main firing were changed from 200 ° C. for 30 minutes to 200 ° C. for 40 minutes, and a VA mode liquid crystal display device was produced.

<Example 7>
A liquid crystal cell was prepared in the same manner as in Example 3 except that the liquid crystal aligning agent [L2] was changed to the liquid crystal aligning agent [L3] and the conditions for the main firing were changed from 200 ° C. for 30 minutes to 200 ° C. for 40 minutes. A VA mode liquid crystal display element was manufactured.

<Comparative Example 3>
A liquid crystal cell was prepared in the same manner as in Example 3 except that the liquid crystal aligning agent [L2] was changed to the liquid crystal aligning agent [L1] and the conditions for the main firing were changed from 200 ° C. for 30 minutes to 200 ° C. for 40 minutes. A VA mode liquid crystal display element was manufactured.

<Example 8>
A liquid crystal cell was produced in the same manner as in Example 3 except that the conditions for the main firing were changed from 200 ° C. for 30 minutes to 230 ° C. for 30 minutes, and a VA mode liquid crystal display device was produced.

<Example 9>
A liquid crystal cell was prepared in the same manner as in Example 3 except that the liquid crystal aligning agent [L2] was changed to the liquid crystal aligning agent [L3] and the conditions for the main firing were changed from 200 ° C. for 30 minutes to 230 ° C. for 30 minutes. A VA mode liquid crystal display element was manufactured.

<Comparative example 4>
A liquid crystal cell was prepared in the same manner as in Example 3 except that the liquid crystal aligning agent [L2] was changed to the liquid crystal aligning agent [L1] and the conditions for the main firing were changed from 200 ° C. for 30 minutes to 230 ° C. for 30 minutes. A VA mode liquid crystal display element was manufactured.

As shown in Table 2, in the liquid crystal display elements of Examples 3 to 5 in which the polymerization inhibiting component was introduced, the response speed was improved by the liquid crystal alignment film as compared with Comparative Example 2 in which the polymerization inhibiting component was not introduced.
In Examples 3 to 5, in the liquid crystal aligning agent [L4] of Example 5, SMB is added to form a polymerization inhibiting component as a part of polysiloxane constituting the liquid crystal alignment film. Furthermore, the polysiloxane contained is formed by copolymerizing SMB with other alkoxysilane monomers.

Next, when paying attention to the firing time of the liquid crystal alignment film, in the liquid crystal display element of Comparative Example 3 in which no polymerization inhibiting component was introduced, since the firing time was lengthened, a comparison in which no polymerization inhibitor was introduced in the same manner The response speed was significantly lower than in Example 2. This is considered to be because by increasing the baking time, the polymerization reaction of C═C bonds in the liquid crystal alignment film progresses during baking, and the amount of reactive C═C bonds decreases.

On the other hand, the liquid crystal display elements of Examples 6 and 7 into which the polymerization inhibiting component was introduced exhibited the same response speed as the corresponding liquid crystal display elements of Examples 3 and 4 even when the firing time was increased.
In the liquid crystal display elements of Examples 6 and 7 in which the polymerization inhibiting component was introduced, the firing time of the liquid crystal alignment film was the same, and the response speed was improved as compared with Comparative Example 3 in which the polymerization inhibiting component was not introduced.

Next, when paying attention to the firing temperature of the liquid crystal alignment film, in the liquid crystal display element of Comparative Example 4 in which no polymerization inhibiting component was introduced, since the firing temperature was increased, a comparison in which no polymerization inhibitor was introduced in the same manner The response speed was significantly lower than in Example 2. This is considered to be because by increasing the baking temperature, the polymerization reaction of C═C bonds in the liquid crystal alignment film progresses during baking, and the amount of reactive C═C bonds decreases.

On the other hand, the liquid crystal display elements of Examples 8 and 9 into which the polymerization inhibiting component was introduced exhibited a response speed equivalent to that of the corresponding liquid crystal display elements of Examples 3 and 4 even when the firing temperature was increased.
In addition, in the liquid crystal display elements of Examples 8 and 9 in which the polymerization inhibiting component was introduced, the response speed was improved as compared with Comparative Example 4 in which the polymerization inhibiting component was not introduced even when the firing temperature of the liquid crystal alignment film was the same.

From the liquid crystal aligning agent of the present invention, it is possible to form a vertical alignment liquid crystal alignment film capable of photo-alignment processing and enabling high-speed response of the liquid crystal display element, and has high productivity and excellent display quality. A VA mode liquid crystal display element can be manufactured. The liquid crystal display element constitutes a VA mode liquid crystal display element of high display quality, and can be suitably used for a portable information terminal such as a large-sized liquid crystal TV or a smartphone displaying a high-definition image.

The entire contents of the specification, claims and abstract of Japanese Patent Application No. 2012-244547 filed on November 6, 2012 are incorporated herein as the disclosure of the specification of the present invention. Is.

Claims

It contains a polysiloxane component (A) formed from a raw material alkoxysilane containing an alkoxysilane represented by the following formula (1) and an alkoxysilane represented by the following formula (3), and a polymerization inhibiting component (B). The liquid crystal aligning agent, wherein the polymerization inhibiting component (B) is contained as a constituent part of the polysiloxane component (A) or as a substance different from the polysiloxane component (A).
R 1 Si (OR 2 ) 3 (1)
(R 1 is a group represented by the following formula (2), and R 2 is an alkyl group having 1 to 5 carbon atoms.)

(Y 1 is a single bond, — (CH 2 ) a — (a is an integer of 1 to 15), —O—, —CH 2 O—, —COO— or —OCO—.
Y 2 is a straight or branched hydrocarbon group having 3 to 8 carbon atoms containing a single bond or a double bond, or — (CR 17 R 18 ) b — (b is an integer of 1 to 15 , R 17 and R 18 each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
Y 3 is a single bond, — (CH 2 ) c — (c is an integer of 1 to 15), —O—, —CH 2 O—, —COO— or —OCO—.
Y 4 is a divalent cyclic group selected from a single bond, a benzene ring, a cyclohexyl ring, and a heterocyclic ring, or a divalent organic group having 12 to 25 carbon atoms and having a steroid skeleton, on the cyclic group Arbitrary hydrogen atoms are substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom May be.
Y 5 is a divalent cyclic group selected from the group consisting of a benzene ring, a cyclohexyl ring and a heterocyclic ring, and an arbitrary hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, carbon It may be substituted with an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom.
n1 is an integer of 0-4.
Y 6 is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxyl group having 1 to 18 carbon atoms, or a fluorine-containing alkoxyl group having 1 to 18 carbon atoms. )

(R 21 , R 22 and R 23 are each independently —OCH 3 , —OC 2 H 5 , —OCH (CH 3 ) 2 , —OC (CH 3 ) 3 , —CH 3 , —Ph (phenyl group) ), —Cl, —OCOCH 3 , —OH, or
R 24 is a hydrogen atom or a methyl group.
Y 21 is a straight or branched hydrocarbon group having 1 to 8 carbon atoms which may contain a single bond or a double bond.
Y 22 represents a single bond, —O—, —CO—, —COO—, —OCO—, —NH—, —N (CH 3 ) —, —NPh—, —NHCO—, —N (CH 3 ) CO—. , -NPhCO -, - NHSO 2 - , - N (CH 3) SO 2 -, - NPhSO 2 -, - S -, - SO 2 -, - NHCONH, -N (CH 3) CONH -, - NPhCONH-, The bonding group is selected from —NHCOO— and —OCONH—.
Y 23 is a single bond or a linear or branched hydrocarbon group having 1 to 8 carbon atoms.
Y 24 is a single bond or a linear or branched hydrocarbon group having 1 to 8 carbon atoms.
Y 25 represents a single bond, —O—, or —NZ 2 —, and Z 2 represents a hydrogen atom, a linear or branched hydrocarbon group having 1 to 18 carbon atoms, an aromatic ring group, or an aliphatic ring. It is a group.
Cy is a divalent cyclic group selected from the following and bonded at an arbitrary substitution position. An arbitrary hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, or 1 to 3 carbon atoms. May be substituted with an alkoxy group, a cyano group, a fluorine atom, or a chlorine atom. )

(Z 1 is a linear or branched divalent hydrocarbon group having 1 to 18 carbon atoms which may contain an aromatic ring group or an aliphatic ring group.)
The raw material alkoxysilane further contains an alkoxysilane represented by the following formula (5) having a group having a polymerization inhibiting function, and the polymerization inhibiting component (B) is a constituent part of the resulting polysiloxane component (A). The liquid crystal aligning agent of Claim 1 contained.
R a Si (OR b ) 3 (5)
(R a is a group having a polymerization inhibiting function, and R b is an alkyl group having 1 to 5 carbon atoms.)
A polysiloxane formed from an alkoxysilane represented by the following formula (5) having a group having a polymerization inhibiting function or a polysiloxane containing an alkoxysilane represented by the following formula (5) is the polysiloxane component (A The liquid crystal aligning agent of Claim 1 contained as another substance.
R a Si (OR b ) 3 (5)
(R a is a group having a polymerization inhibiting function, and R b is an alkyl group having 1 to 5 carbon atoms.)
The liquid crystal aligning agent according to claim 2 or 3, wherein the alkoxysilane represented by the formula (5) is the following compound.
The polymerization inhibiting component (B) contained as a substance different from the polysiloxane component (A),
The liquid crystal aligning agent according to claim 1, which is phenol, catechol, benzoquinone, hydroquinone, or an ester, etherified product or alkylated hindered phenol, phenothiazine, hindered amine, hydroxyamine or nitrosamine.
6. The liquid crystal aligning agent according to claim 1, wherein the polymerization-inhibiting component (B) is contained in an amount of 0.01 to 20 mol% with respect to the polysiloxane component (A).
In the raw material alkoxysilane, the alkoxysilane represented by the formula (1) is contained in an amount of 2 to 30 mol%, and the alkoxysilane represented by the formula (3) is contained in the raw material alkoxysilane in an amount of 5 to 70 mol%. The liquid crystal aligning agent according to any one of claims 1 to 6.
The liquid crystal aligning agent according to any one of claims 1 to 7, wherein the raw material alkoxysilane further contains an alkoxysilane represented by the following formula (4).
R 3 Si (OR 4 ) 3 (4)
(R 3 is an alkyl group having 1 to 30 carbon atoms in which a hydrogen atom is substituted with an acrylic group, acryloxy group, methacryl group, methacryloxy group or styryl group. R 4 is an alkyl group having 1 to 5 carbon atoms. is there.)
The liquid crystal aligning agent according to any one of claims 1 to 7, comprising a polysiloxane (C) formed from an alkoxysilane represented by the following formula (6).
Si (OR 15 ) 4 (6)
(R 15 is an alkyl group having 1 to 5 carbon atoms.)
At least one of the polysiloxane component (A) and the polysiloxane (C) is a polysiloxane obtained by reacting an alkoxysilane further containing an alkoxysilane represented by the following formula (7): The liquid crystal aligning agent of any one of these.
(R 13 ) n2 Si (OR 14 ) 4-n (7)
(R 13 represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms in which the hydrogen atom 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.
R 14 is an alkyl group having 1 to 5 carbon atoms, and n2 represents an integer of 0 to 3. )
A liquid crystal alignment film obtained by using the liquid crystal aligning agent according to any one of claims 1 to 10.
A liquid crystal display element having the liquid crystal alignment film according to claim 11.
A pair of liquid crystal alignment films according to claim 11 and a liquid crystal layer sandwiched between the liquid crystal alignment films, wherein the liquid crystal alignment film is irradiated with light in a state where a voltage is applied to the liquid crystal layer. A VA mode liquid crystal display element formed by the above method.